implementation of the laser scanning system used for dermatological treatments
DESCRIPTION
This thesis discusses the implementation of laser scanning system used for dermatological treatments. To obtain the designated therapeutic area this system uses a photographic device and then transfers the image position to a driver device. Selecting the boundaries of the designated treatment area is done either manually or automatically. After calculating the chosen area, the system divides the area into many therapeutic “points” (the actual number of points depending on the laser spot size). In the meantime, the system also determines the coordinates of every therapeutic point. The brand-new method directs the laser beam to every designated point to perform the treatment process. The operator does not need to operate manually at all. Consequently, the flaws inherent with manual operations can be avoided, and the therapeutic area can be controlled with greater precision. Moreover, by utilizing the image-orientated control system, the energy of laser is distributed over the skin steadily and evenly. Another advantage of this system is that it avoids laser exposure to the operator’s eyes.TRANSCRIPT
國立彰化師範大學國立彰化師範大學國立彰化師範大學國立彰化師範大學機電工程學系機電工程學系機電工程學系機電工程學系
碩士論文碩士論文碩士論文碩士論文
雷射掃瞄皮膚治療系統之研製
Implementation Of The Laser Scanning System Used
For Dermatological Treatments
研 究 生：郭 奕 谷 撰
指導教授：陳 明 飛 教授
A Thesis Submitted to the Department of Mechatronics Engineering
National Changhua University of Education
in Partial Fulfillment of the Requirements
For the Degree of Master of Science
中 華 民 國 九 十 六 年 七 月
July, 2007
ii
摘要摘要摘要摘要
本論文研發雷射光掃瞄系統來做皮膚方面的治療。此系統使用影像擷
取裝置來取得所欲治療範圍後，再轉換至驅動裝置定位。可以用手動或自
動方式來選擇治療區域的範圍。所選擇區域經過計算後，系統會將其分割
成許多的“點”(視雷射光點大小)；並在此同時，系統亦決定每個治療點
的座標位置。此全新的治療方式將雷射光導引至每個被選擇的點來進行治
療。使用者完全不必用手操作治療病人；因此，在此文章內所提的手動治
療失誤將可以避免，治療區域也因此可以控制的更準確。此外，利用影像
導引控制系統，雷射能量可以穩定，平均地分配在皮膚上。另外一個好處
是使用者的眼睛可以避免曝露在雷射光之下。
iii
Abstract
This thesis discusses the implementation of laser scanning system used
for dermatological treatments. To obtain the designated therapeutic area this
system uses a photographic device and then transfers the image position to a
driver device. Selecting the boundaries of the designated treatment area is
done either manually or automatically. After calculating the chosen area, the
system divides the area into many therapeutic “points” (the actual number of
points depending on the laser spot size). In the meantime, the system also
determines the coordinates of every therapeutic point. The brand-new method
directs the laser beam to every designated point to perform the treatment process.
The operator does not need to operate manually at all. Consequently, the flaws
inherent with manual operations can be avoided, and the therapeutic area can be
controlled with greater precision. Moreover, by utilizing the image-orientated
control system, the energy of laser is distributed over the skin steadily and
evenly. Another advantage of this system is that it avoids laser exposure to the
operator’s eyes.
iv
CONTENTS
Abstract (Chinese) .............................................................................................. ii
Abstract (English) ............................................................................................. iii
Contents............................................................................................................. iv
List of Tables ....................................................................................................... vi
List of Illustrations ........................................................................................... vii
Chapter 1 Introduction .................................................................................. 1
1.1 Preface ................................................................................................ 1
1.2 Background ......................................................................................... 6
1.3 Patent review ........................................................................................ 8
1.4 Purpose of this study .......................................................................... 9
1.5 Structure of this study ....................................................................... 11
Chapter 2 The Laser System ....................................................................... 12
2.1 Laser source ...................................................................................... 12
2.2 Image system .................................................................................... 14
2.3 Optical compensation system ........................................................... 16
2.4 Scanning system ............................................................................... 22
Chapter 3 Galvo Scanner and Beam Alignment ........................................... 26
3.1 Galvanometer ................................................................................... 26
3.2 The mirrors ....................................................................................... 27
3.3 The driver board ............................................................................... 29
3.4 Alignment procedure ........................................................................ 29
Chapter 4 Assembly and Verification ......................................................... 33
4.1 Assembly concept ............................................................................. 33
4.2 Assembly procedure ......................................................................... 35
4.3 Verification ......................................................................................... 36
4.4 Target area control .............................................................................. 41
Chapter 5 Conclusion .................................................................................. 48
5.1 Feature of this device ........................................................................ 48
5.2 Future development .......................................................................... 49
v
Appendix A Other dermatology laser patent analysis list ........................... 52
Appendix B Wavelight laser technology patents ........................................ 55
Appendix C InPro Innovations patents ....................................................... 57
References ...................................................................................................... 61
vi
LIST OF TABLES
Table Page
1.1 Reference list of market product ............................................................ 2
1.2 Types of human skin .............................................................................. 5
3.1 Mirror manufacturer ............................................................................. 28
4.1 Parts description ................................................................................... 37
vii
LIST OF ILLUSTRATIONS
Figures Page
1.1 Skin structure ........................................................................................... 4
1. 2 Wavelength absorption ............................................................................ 4
2.1 Optics compensation & scanning system .............................................. 18
2.2 The astigmatic aberration waist ties the position and the circular......... 21
2.3 Gauss light beam relations after lens function ..................................... 22
3.1 Beam alignment ................................................................................... 32
4.1 The 3-D structure of this new invention .............................................. 38
4.2 The 3-D structure of another direction ................................................ 39
4.3 The top view of movement situation 1 ................................................ 40
4.4 The top view of movement situation 2 ................................................ 40
4.5 The system schematic diagrams .......................................................... 41
4.6 Flow chart ............................................................................................ 42
Pictures Page
1.1 Treatment cabinet ................................................................................... 6
1.2 Lighting boxes ....................................................................................... 6
1.3 Hand probe ............................................................................................. 7
1.4 Mechanical arm ...................................................................................... 7
4.1 Auto-control scanning system – view 1 ............................................... 33
4.2 Auto-control scanning system – view 2 ............................................... 34
4.3 Small circle calibration ........................................................................ 43
4.4 Large circle calibration ........................................................................ 43
4.5 Cross calibration .................................................................................. 44
4.6 Treatment area calibration ................................................................... 44
4.7 Operation demo .................................................................................... 45
4.8 Colorful psoriasis – test 1 ...................................................................... 46
4.9 Colorful psoriasis – test 2 .................................................................... 46
1
Chapter 1 Introduction
1.1 Preface
Lasers have been used in dermatology for decades since the 1960’s, and are
one of the benefits of high technology, but they still frighten many people.
This fear is mainly due to a lack of understanding of lasers, especially the
principles of laser treatment. Basically there are four interactions between light
energy and skin tissue: they are photoablation, thermal, electromechanical, and
photochemical [1]. Specifically, the treatment of psoriasis [2] mainly employs
photochemical interaction theory. It involves a biological effect that is directly
proportional to the exposure of the total energy dose over a specific area of skin,
no matter whether continuous or fractionated, and it’s light-induced reactions
are sensitive to wavelength.
In fact, a laser emits one kind of light energy. By lighting the skin surface,
the skin is affected by the reflection, scattering, penetration, and absorption of
that energy [3, 4]. By using a specific wavelength of light, a laser reaches the
designated tissue depth. Then the thermal energy, which is absorbed and also
transformed by the cells, destroys and activates the tissue to regrow and rebuild
the treated area. In this way, some level of therapy can be achieved.
Lasers have been used for medical dermatology applications such as the
removal of port wine stains, acne scars, tattoos, dark spots, and other blemishes
for over ten years. Lasers are also used for a growing number of cosmetic
procedures including teeth whitening, hair removal, and the treatment of
wrinkles.
2
In order to present a clear picture of laser therapy, and to get some idea of
its possible applications, it is helpful to mention products that are easily obtained
from the laser market. A reference list of marketed laser products is shown in
Table 1.1 with the manufacturer, the product name, specifications, a photo of the
product, product function, classification, and price provided.
Some parts of the skin’s structure (see Figure 1.1) can absorb the high
energy from the stable wavelength of a laser (see Figure 1.2) [5] and react in the
twinkling of an eye, so the designated treatment result can be obtained due to the
destruction of one specific element in the skin.
Table 1.1 Reference list of market products
Manufacturer Healiohealth LazrPulsr ETrans
Product name LTU 1000 LazrPulsr 4X Softlaser
Specification 670nm, 1mW 635nm, 20mW 670nm, 6mW
Photo
Function Pain healing Wounded recovering Rejuvenating
Classification Class II Class II Class II
Price(USD) 690 4,995 129
3
Table 1.1 - Continued
Manufacturer Beauty Beauty Beauty
Product name SI-808 L-Dr.890 HFL850
Specification 808nm 890nm 850nm/LD,
660nm/LED
Photo
Function Hair removing Whitening Rejuvenating
Classification Class III R Class III R Class II
Price(USD) 200 210 --
Manufacturer Omega Beurer Win/Health
Product name Visible red probe SL30, VSL40 HairMax
Specification 660nm, 50mW 635-675nm, 6mW 655nm, 4mW
Photo
Function Hair removing Whitening Hair growing
Classification Class III B Class III A Class III R
Price(USD) -- 159 346
4
Figure 1.1 Skin structure
Figure 1.2 Wavelength absorption
The laser lighting time is quite short; thus, the energy will not be spread to
5
the surrounding tissue, protecting harmless skin tissue from destruction.
However, different skin colors have different results from the same energy.
Traditionally, for laser treatment reference, all human skins are classified into
six types (see Table 1.2) [6] from light to dark in color. The doctor chooses the
proper laser energy level or energy dose based on the patient’s skin type to
prevent over lighting or over lasing the skin.
Table 1.2 Fitzpatrick Classification Scale
Types Interaction with Sun burn Skin Eyes Hair
TYPE
I
Always burns in the sun. Never
gets tan.
Extremely
fair skin
Blue/green
eyes
Usually blonde
or red hair
TYPE
II
Sometimes burns, but it will
turn into a tan. Most
Caucasians
Fair skin Green/brown
eyes
Light brown to
brown hair
TYPE
III Usually tans, rarely burns.
Medium
skin Brown eyes
Light brown to
brown hair
TYPE
IV
Seldom burns.
Possibly Mediterranean, Asian,
or Hispanic descent.
Olive skin Black eyes Brown or black
Hair
TYPE
V
Almost never burns.
Possibly Mediterranean,
Hispanic, light skin
African-American, or other
descent.
Dark
brown skin Black eyes Black Hair
TYPE
VI
Never burns.
Possibly Indian, West Indian
descent, or African-American.
Black skin Black eyes Black Hair
6
For psoriasis lesions, traditional treatment methods is using 311~313nm
wavelength lamps installed in one cabinet (in Picture 1.1) [7] or lighting boxes
(in Picture 1.2) [8]. Patients step into the cabinet exposing the psoriasis lesions
to the light [9, 10, 11, 12] after taking vitamin A acid, Retinoid; or wiping the
steroid Anthralin, Tar oil, on their skin [13]. However, most of the traditional
treatments have side effects and require about 25 to 30 procedures per treatment.
The worst part is that these treatment methods have to be changed after two or
three months in case the human body builds up an immunity to the medication
Picture 1.1 Treatment cabinet Picture 1.2 Lighting boxes
1.2 Background
While dermatologists are professionally trained, it is noted that current
308nm excimer laser skin therapeutic devices all need to use manual probes
(in Picture 1.3) [14] or mechanical arms (in Picture 1.4) [15]. The steps of a
manual probe or mechanical arm operation are the same. First, both the
7
designated treatment area and its on-screen target area are determined by the
doctor’s naked eyes; second, the designated treatment area is covered by moving
the laser projecting probe by hand; and, finally, the doctor manually controls
when the laser is projected to perform the treatment process.
Based on these steps, it is easy to find that a lengthy, continuous surgery
would probably result in some inaccuracies and side effects from the doctor; for
example, torpor of hand movement, improper control of muscles, eye fatigue,
etc. These flaws might do unexpected harm on the healthy tissues and cells
around the desired treatment area. Moreover, re-treatment of the same area due
to unavoidable human forgetfulness, or miscalculation of laser projection times,
would both affect the treatment result.
Picture 1.3 Hand probe Picture 1.4 Mechanical Arm
Because manual probes and mechanical arm operations are not convenient
8
or user friendly, and because operation times are too long for mild or medium
psoriasis lesions, these treatment methods are not efficient for either doctor or
patient. Therefore, an auto-controlled scanning method was created. X, Y
axes galvanometers with coated mirrors were installed to precisely position the
laser light. A CCD camera and touch screen panel are used by the doctor to
monitor the operation. A footswitch controls when the light is projected on the
psoriasis lesions. This method shortens operation time and also solves
problems due to human flaws from both the doctor and the patient’s skin.
1.3 Patent review
Because the auto-controlled laser scanning system is claimed as a
dermatology laser product invention, a patent review can be discussed from two
main competitors: Wavelight and PhotoMedex. It is noted the company InPro
Innovations is inactive in the medical device field.
There are 2,985 dermatology-related patents worldwide, including 33 cases
of dermatological laser devices and treatment methods (See Appendix A).
Most of the dermatology laser treatment device patents for psoriasis on the
market are from PhotoMedex and Wavelight, and a very small percentage are
from Inpro Innovations. Hence, this patent review focuses it’s analysis on
these three companies with the results presented below.
1. Wavelight Laser Technology has 22 patents (see Appendix B), but only
two relevant patents to dermatology devices: (1) a lamp used in the treatment of
skin (DE), and (2) a laser device for the treatment of patient skin and other
dermatological processes (DE). These patents are not relevant to the
9
auto-controlled scanning system.
2. PhotoMedex has only two patents and seems focused on handheld optical
fibers to control laser energy: (1) controlled delivery doses of ultraviolet light
for treating skin disorders (WO02055149-2002-07-18), a patent that claims the
scope of using handheld fibers to control the treatment doses, and (2) rare
gas-halogen excimer lasers with baffles (EP1564851-2005-08-17). These
patents are not related to the auto-controlled scanning system.
3. InPro Innovations GmbH is in the laser welding industry and has no
patents concerning the auto-controlled scanning system (See Appendix C).
1.4 Purpose of this study
Psoriasis has been treated successfully with narrow-band UVB radiation
for twenty years [16, 17]. Now, with the excimer laser system, it is possible
to selectively apply ultraviolet radiation at a wavelength of 308nm [18]. This
concept of selectivity allows only the diseased skin to be exposed to the
radiation while protecting the healthy skin from contact, making it possible to
work with higher laser treatment doses at one time. As a result, it is possible
to achieve effective clearing of psoriasis with long periods of remission [19].
In comparison to conventional forms of treatment, the new method, using the
auto-controlled scanning system rather than a handheld optical fiber, offers
better results and requires fewer treatment sessions.
There is no real alternative to excimer laser therapy for the treatment of
Vitiligo dermatitis. Given its extensive nature, conventional forms of
10
treatment demand an unusual amount of forbearance and discipline on the part
of patients. Often, treatments end with unsatisfactory results. On the other
hand, the excimer laser system gives the patient the opportunity to drastically
reduce the number of required treatment sessions. Re-pigmentation is
achieved via stimulation of the melanocytes with relatively high doses of
lasing energy. Here, the selective application made possible by the new
design system is a decided advantage.
Therefore, based on the area designated for destruction and the choice of
proper laser type and proper energy, the operator could destroy the target at will
without damaging other harmless or healthy tissues. That is to say, treatment
with a laser is quite sophisticated and safe under such conditions. Using the
selective excimer laser wavelength of 308nm is the ultimate treatment for
Psoriasis and Vitiligo dermatitis. However, 308nm excimer laser market
products use optical fibers to deliver laser energy onto the designated skin
lesions by either a handheld device or mechanical arm. The operator has some
inconvenience and the patient also suffers the risk of having the same area
unintentionally re-treated, or laser projection times that are too long. The
auto-controlled scanning system provides the best solution to these problems
and reduces human flaws to minimize the risk of excessive laser exposure.
The purpose of this thesis is to show how to build the auto-controlled
scanning system, and to analyze and explain the concepts behind the system.
11
1.5 Structure of this study
The information needed to show how to build the auto-controlled scanning
system, and to analyze and explain the concepts behind the system, are
presented in the following chapters.
Chapter 2 discusses the laser device used for the auto-controlled scanning
system. The structure of different components and explanations of each
function are given that: the laser source control and the laser power monitoring
system, the image system technology, the optical compensation system, and
the scanning system. Chapter 3 explains the galvo based scanner and
introduces its key components. The procedures and techniques of beam
alignment are then shown there after. In Chapter 4, the assembly and
verification methods used to prove that the auto-controlled scanning system is
constructed and performs according to the original design are provided.
Chapter 5 discusses the unique features of the auto-controlled laser
scanning system and possible future development trends, discussing improved
function and effectiveness from hardware and software upgrades. In the
mean time, the scanning system can also be used in other industries or for
other purposes.
12
Chapter 2 The Laser Device
The laser system used in this thesis contains laser source control and a
laser power monitoring system, a laser spot scanning and optics compensation
system, a skin image identification and skin color information database
construction, a position mark to establish a correlation technology control
system, and a clinical experimental and treatment parameter construction. An
explanation of the research technique follows.
2.1 Laser source
Traditional dermatologists treated skin conditions like psoriasis and
Vitiligo dermatitis with medicines like tazarotene, calcipotriene, and so on.
The treatment effects, however, were not remarkable and there were obvious
side effects. Therefore, in modern times a method of treatment using UV
lamp lighting was developed. The principle was similar to treatment by
radioactive rays. Because the light illumination method was dependant on
the wavelength, the intensity, and the target area, control was not easy;
therefore, the treatment effect was not entirely positive. The treatment course
was excessively long and the reoccurrence probability was high.
Nearly a decade of research and development resulted in recognizing the
positive effects that UVB wave band 311 nanometer ultraviolet rays have in
the treatment of skin diseases such as psoriasis, particularly by enclosing the
target area. However, the delivery of the illumination was still too broad for
13
precisely controlled treatments, and it was easy to harm the healthy
surrounding tissues. The 308nm excimer laser was found to have the single
wavelength with the most direct effect on skin tissue; therefore, starting from
1998, the United States focused its efforts on researching this wavelength and
developing 308nm laser treatment devices. Germany followed the research
and developed devices after the US results were published.
By directly and selectively destroying unhealthy tissues, the 308nm
excimer laser greatly improves the treatment course and the curative effect
over conventional UV lamp lighting technology, and by avoiding the UV
lamp’s large illumination area the probability of damaging healthy skin is
reduced [20]. Gradually, this laser has entered the mainstream for treating
skin psoriasis.
The development of the 308nm excimer laser for skin treatment is now a
priority project for several countries. Because this thesis utilizes an optical
delivery system, the laser needs a lower power than other kinds of laser market
products. Since the excimer laser has short-term stability, the laser power
monitoring system is used to maintain the laser power and test the laser power
stability. In this thesis, we use the feed-forward control concept. By using a
power meter to gauge laser power, the design makes it possible to control laser
power through an attenuator mirror, allowing the power to be maintained at a
set value. In addition to the power stabilizing control, this thesis will focus
on the amount of laser power adjustments needed for each kind of skin disease
to establish laser power reference values that help the doctor set up the
treatment parameters.
14
The laser beam output delivery is of the pulse wave type. Generally
speaking, the shorter the laser pulse time, the more centralized the energy.
Therefore, for the same laser beam energy, a shorter pulse time means its
power is higher. This thesis will use a laser with a short pulse duration of
10ns (nanoseconds) to serve the function of selectively treating only the target
area.
In addition, part of this system develops a database of laser power
parameters for skin treatment. In this part, people of various skin types are
asked to accept a designed laser energy test, called the minimal erythema dose
(MED). The MED tests for the appearance of erythematous skin. The test
results will provide the doctor with a reference on which to base adjustments
of the laser dosage.
2.2 Image system
This thesis intends to develop a treatment method that picks up the image
of the skin disorder, recognizes the area of the disorder, and uses a localized
luminous spot with a base matrix to determine image position. This
information is then combined with a scanning system to precisely deliver laser
energy on the designated location. This part of the thesis will establish the
target acquisition technology, the conformity of the image with disorder shape
identification, the treatment zone scanning coordinate transformation and the
control system, establish the different skin color identification information
database, and so on.
1. The target acquisition technology maintains alignment between the
15
laser’s scanning coordinates and the image coordinates from the treatment area.
The thesis’s proposed direction of development will use a standard grid with
the scanning treatment scope to align the central point of the treatment area
with a laser scanning reference point for precision alignment of the laser beam
with the target.
2. The conformity of the image of the skin with the disorder shape
identification and the image scanning coordinate transformation system
primarily establish the image center and the laser spot scanning system
reference point to a zero point localization. The image is strengthened by
using a filter, automatic binaryzation and disorder region edge detection.
Then the image scanning coordinates values are transformed to the laser beam
scanning system coordinate values in order to continue with the skin treatment.
Because the pick up image size is bigger than the laser treatment scope, a
working space is designed in the software to treat a square of the region.
When actual treatment starts, the region of disorder must be present in the
square to be identified. In addition, the doctor may also directly touch the
screen to revise the image detected region or use a mouse to select the
treatment.
For the laser scanning field depth position and the focusing image to
determine the position, this thesis plans to install an infrared range detection
sensor to measure the designated treatment region within the CCD distance.
This may further confirm the field depth position, to help achieve automation
and precise treatments.
16
3. With regard to the different skin colors, it might be necessary to
establish a skin treatment image identification information database. This
thesis will obtain image parameter settings by collecting information about
different skin colors and pictures of the different skin diseases. A basic
parameter information database will be constructed to provide a reference to
the doctor for the laser treatment.
4. Most skin diseases are often distributed over disperse regions, and are
also distributed over three-dimensions. With regards to this aspect of
treatment, two kinds of techniques will be adopted. The first technique has
the doctor to mark a symbol on the center of the therapy region, and use the
image servo-control technology to move the platform to scan the image’s
central point until it matches the symbol alignment before the treatment starts.
The second technique divides the region of the skin disorder, using
medical-use asphalt wiped on the skin to make sections for alignment. This
might enhance skin disorder identification and might distinguish clearly the
treatment regions from the non-treatment regions. This sectional treatment
technique might also help avoid the spot from becoming elliptical in shape due
to slope deviations. which might cause healthy skin to be treated.
2.3 Optics compensation system
A diagram of the optics compensation part of the system is shown in
Figure 2.1. Laser light is sent by the laser source module to the optics
compensation system to maintain the spot shape and size after adjustments by
the power control system feedback. The laser light then enters the scanning
17
system on its way to perform treatments on skin.
The design of the optics compensation system takes into consideration
scan speed, spot shape, size, power density, the two-dimensional scanning
mirror and the compensating mirror module, to handle a small spot with high
power density, and a large field depth illumination window (100mm x 100mm).
The purpose of two-dimensional scanning and the optics mirror module is to
eliminate aberrations.
18
Figure 2.1 Optics compensation & scanning system
This thesis’s pulse wave excimer laser uses XeCl premix gas as the active
medium to generate a wavelength of 308nm. Based on this laser’s special
resonant cavity optical design, the laser output has a beam with an astigmatic
aberration. The divergence angle is 1mrad x 0.5mrad. The light beam spot is
an ellipse out of the pupil aperture. The beam sizes for the long and short
axis are 6mm x 3mm, and may be expressed as:
Image System
Laser source and
Laser power monitor
Optics
Compensation
System Scanning System
Projecting windows
19
−×
×
++−×
−×
−×
×=
−−
2
0
1
2
0
1
22
2
2
2
221
00
0
2
1
2
1
22
yx
yX
yx
/
yx
W
)az(tanjexp
W
ztanjexp
R
y
R
xzjkexp
)z(W
yexp
)z(W
xexp
)z(W
W
)z(W
WE)z,y,x(E
πλ
πλ
+=
22
01z
WzR x
x λπ
; ( )( )
−+−=
22
01
az
WazR
y
y λ
π;
( )
+=
2
2
0
2
0
2 1x
xxW
zwzw
πλ
; ( ) ( )
−+=
2
2
0
2
0
2 1y
yyW
azwzw
πλ
;
x
xw0πλ
θ = , y
yw 0πλ
θ =
in which λ is the wavelength, w0x and w0y are the waist spot radii, θx and θy are
the x direction and y direction divergence angles, α is the astigmatic aberration
distance, corresponding in the x-z plane beam to the y-z plane beam distance.
Traditionally, the astigmatism ellipse will be reshaped to a circular or
square shape by using one pair of anamorphic prism lenses, collimation optics,
and a cylinder mirror set of lens combinations. Moreover, to find the suitable
position to join the astigmatic aberration compensation part and the
collimation mirror set might also create a parallel light effect. Because of the
astigmatic aberration, the light beam in some position should be circular,
( ) ( )zwzwyx
=
20
By substituting these in the above Gaussian light beam equation, it should
be possibly to get position z,
( )
−+±
−=
22
0
2
02
2
2
00
2
02
0
2
0
21
1yxyxx
yx
,wwawwaw
wwz
λπ
The above equation represents the two positions of the beam spot as
circular, the position of long and short axis is reciprocal, but the divergence
angle is invariable. Inserting a suitable astigmatic aberration optics part in
this position should make it possible to shape the light beam as shown in
Figure 2.2, transforming an elliptical Gaussian light beam into a full circle,
symmetrical Gaussian beam.
The excimer laser divergence angle of 1mrad x 2mrad is approximately in
parallel. It is possible to enhance the parallelism, but the price must then be
paid in optical width, and this is not really worth doing. But the field depth
length corresponds to the optics mirror group equivalent to the focal size;
therefore, the optical design must be within the field depth and between the
choice illumination spot sizes. The field depth ∆Ζ computation may be
decided by light beam radius wx and the Z relations.
Accordingly, the Gaussian light beam and the lens relationship may result
in the equation below by the ABCD matrix representation:
21
W0x
W0y
z1z2
Figure 2.2 The astigmatic aberration waist ties the position and the circular
symmetry Gauss light beam position
( )
2 2
2 0 1
20 2 2
0 1
1
x x
x
x
x x
f WW
Wf z
πλ
=
− +
;
( )
22
2 0
1 0 1
22 2
0 1
1
x
x x x x
x
x
x x
Wf z W f
zW
f z
πλ
πλ
−
=
− +
As shown in Figure 2.3, this may estimate image point position Z2x and
the equivalent focal lens ƒχ, according to the above equation. It will be
slightly complex if this is directly by the Gaussian light beam and the ABCD
matrix transformation method. Not only is it not possible to design the optics
mirror set directly, but, also, there is no off-the-shelf analysis software
available.
If the light beam divergence angle is not too big, it may be thought of as
the near axis optics. Therefore, to design the optics compensation system it is
possible to use the available principal ray and marginal ray to solve the
problem. In this thesis, a conventional method of light tracing is used to
design the optics system. Generally speaking, using geometrical optics
software, and in view of three types of optics parts, it is possible to design and
optimize the performance within a short period of time.
22
Z1x Z2x
W0x1 W0x2
Figure 2.3 Gauss light beam relations after lens function
2.4 Scanning system
At present the market laser products for the treatment of psoriasis lesions
primarily use optical fibers. Because the optical fiber projecting area and the
optical fiber delivery port is numerical aperture related, it has a bigger
divergence angle; therefore, the projecting spot size is large. In fact, human
error is unavoidable since the doctor must use manual methods, and the
operation stability, precision, response time and the projecting spot size choice
is determined completely by doctor's skill and experience. In order to
improve the operation stability, and the precision of the projecting spot size,
Germany's Wavelight Corporation used a method that combined mirror
projecting and a mechanical arm to treat the patient. It improved stability, but
the flexibility was poor, it still used optical fiber delivery, and the cost of the
system was high.
In addition, the optical fiber method has two important issues: one is the
insertion loss, another is the optical fiber loss. Because optical fiber delivery
uses one kind of multi-mold optical fiber, leakage is big. Besides, the optical
23
fiber twists and curves during the operation resulting in massive energy loss.
Simultaneously, it changes the exposure intensity, causing the degree of
illumination to be very difficult to maintain constantly.
Normally, a glass optical fiber has a low absorption band around 1.3µm
and 1.5µm, but a 0.308µm or 308nm wavelength has a high absorption rate.
In order to revise these shortcomings, it is necessary to enhance laser power to
make up for the losses. But high power laser energy has a bad impact on the
plasma tube and the electrode, shortening the life of the laser. Therefore, the
cost is high. Furthermore, it is not easy to control in a fixed spot size when
delivering laser energy through an optical fiber, and during the operation the
optical fiber curves and sways, and is easily and frequently damaged. The
fiber becomes a kind of expensively consumable material.
Therefore, in this thesis, image processing and scanning technology are
unified by utilizing the auto-controlled treatment method. A linear scanning
spot delivered by one pair of stepping motors to actuate the lens angle change.
The two motors are actuated by using the controller to control the scanning
spot frequency at a level and upright position. In order to enable the scanning
precision to achieve a functional size (7mm x 7mm) of 100%, it is estimated
the stepping motor scanning angle with a working distance of 600mm needs to
be approximately 0.069∘. Because of the rotation angle θ of the stepping
motor, the spot will move at an angle of 2θ. Therefore the motor moves each
step approximately 0.035∘.
In order to guide the laser energy into the selected treatment region, that
region must first be recognized. The image has to be transformed into motor
24
coordinates. The scanning optics coordinates are transformed from the image
coordinates to become geometrical positioning data. Then the geometrical
coordinates are sent to the motor to start or stop the direction of rotation. For
this fast treatment method, the X direction motor performs the back and forth
scanning, and the Y direction motor then performs the up and down scanning.
This combination of scanning enables the laser beam to be projected precisely
on the skin.
It is extremely important that the skin treatment is related to laser energy
control. This thesis uses the biggest average density (Fluence) of laser pulse
energy at less than 16mJ/cm², the repetition rate is 225Hz, the spot size is
designed to be 0.49cm² (7mm x 7mm); therefore, the maximum single pulse of
a laser energy dose treating the skin is 8mJ. The National Cheng Kung
University dermatology department provides the reference for treating skin
disease by using an UVB311 ultraviolet ray. The biggest treatment energy at
present is 2.5J/cm². By using UVB311 ultraviolet power, it must take about
five minutes at least to achieve the desired treatment, and the illumination
energy and the treatment area are also not easy to control. This thesis uses an
auto-controlled scanning system that may control the scanning region, and
control the motor scanning frequency and the scanning time. The fine,
accurate control treatment energy needed to reach 2.5J/cm² is only needed for
one second.
This thesis uses an excimer laser system. This is a gas laser that uses
specifically premixed XeCl gas to generate 308 nm light, an ultraviolet
wavelength used to perform skin surgery treatment. After careful data
25
collection, analysis, and study, it was determined that the 308nm wavelength
can be effectively absorbed by the skin to control psoriasis. Also, from an
American Medical Association report, it is found this 308nm excimer laser
emission light can control psoriasis for a one year period [19] which is a great
improvement over the traditional Light Box treatment or various medicinal
treatments involving steroids and antibiotics. The 308nm wavelength has
also been approved by the FDA (Food and Drug Administration, U.S.
Department of Health and Human Services) as a safe and efficient method to
work on human skin and to improve the treatment of some dermatological
lesions over traditional treatments. This information provided the main
motivation to develop this psoriasis treatment device.
26
Chapter 3 Galvo Scanner and Beam Alignment
This chapter focuses on the selection of the galvo scanner components in
order to build the scanner system and to perform the laser beam delivery job
through beam alignment. To make a galvanometer (shortened to “galvo”)
scanner function, three main components are needed: they are the galvo, the
mirror, and the driver board. To achieve the galvo scanning system’s ultimate
performance, it is extremely important in the design phase to properly select
the galvo type and the mirror size [21].
3.1 Galvanometer
When doing this research, the first concerns about the galvo emphasized
speed, accuracy, size and cost. As mentioned above, optical fiber has to be
operated manually and causes some inconveniences during the operation.
Therefore, avoiding the defects of the current laser products becomes a key
point, and the galvo scanner based auto-controlled system is the one that can
solve the problems. This system also offers improved features such as
flexibility of angle, high speed, accuracy, compact size and lower cost.
There are a few companies that offer different galvo selections on the
market such as General Scanning Inc., USA; Cambridge Technology Inc.,
USA; and one from Europe called LM. To choose an appropriate galvo for the
auto-controlled system, a list of specification requirements for the system was
made as listed below [22].
27
Wavelength: 308nm Process Time: minimum 5 minute
Field Size: 10x10cm² Focused Spot Size: 0.49 cm²
Working Distance: 60 cm Accuracy: ±0.1cm
Lifetime: at least 1 year
After comparing different types of galvos, the General Scanning, Inc., the
G120D galvo was selected for the scanning system.
3.2 Mirrors
A mirror must be chosen based on several factors such as cost, stiffness,
weight, thickness, density and material. In order to match the galvo scanner
based system, the mirror must be very thin and light weight, speed and
accuracy in the layer image are also concerned to evaluate overall system
performance [22, 23]. The list for mirror selection specifications are as
follows:
Wavelength: 308nm
Thickness: 1mm
Material: fused silicon
Weight: as light as possible
A lightweight substrate of mirror-grade fused silicon is the best material
for repositioning the mirrors in fractions of a millisecond. Galvo mirrors can
be coated with a variety of metal/dielectric coatings to offer high reflectivity at
different wavelengths and increased laser power throughput. Most laser
28
systems use coaxial HeNe lasers or visible laser diodes to aid with the setup
and alignment of the optical system. It is important to specify mirrors with
good reflection properties at both the primary wavelength and at that of the
alignment laser. This system is using a 308nm ultraviolet wavelength
excimer laser to treat the skin disorder; so the mirror coating selection is
limited. Because of this special requirement for the system, it is very difficult
to find the desired performance mirrors in off-the-shelf markets.
We have to search for companies that can make special design or
custom-made mirrors to fulfill system performance. There are few
companies can manufacture the thickness of the thin mirror, most of them need
to be custom designed. Table 3.1 provides a list of the companies searched.
Table 3.1 Mirror manufacturer
Online Catalog Company Headquarters
Online
Quote
Custom
Order
Custom Plasma Ireland Inc. (Manufacturer)
Ireland
Custom Axsys Technologies (Manuf., Distrib., Sole
Distrib. & Service)
Rochester
Hills, MI
Custom OPCO Laboratory, Inc. (Manuf. & Service)
Fitchburg, MA
Custom Qioptiq Polymer (Manuf. & Service)
La Verne, CA
Custom Tower Optical
Corporation (Manufacturer)
Boynton
Beach, FL
Each one of them has ability to design and manufacture the desired
29
mirrors ; therefore, cost became the last factor used to select the company.
Plasma Ireland, Inc. willingly reduced costs and so became the current supplier
of mirrors for the system.
3.3 Driver board
This system is specially designed for dermatology treatments; but an
attempt was made to search for available driver boards on the market. Most
driver boards use some kind of combination of detected position, galvo drive
current, and velocity of angular and integral-of-error signals to make a
closed-loop system to be controlled at the desired positioning speed and
accuracy. Since the GSI galvo scanner has an available driver board call
“mini sax”, the best selection is their product in order to maintain consistency.
It isn’t necessary to worry about the driver board because the closed-loop
galvo offers the speed, accuracy, and low cost the system needs.
Although the galvo scanner system components are selected, there are still
many choices that can be substituted for the chosen components, and that may
have better or outstanding functions in comparison with them. If better
alternatives are found during the assembly process, they may be chosen to
improve system performance. At this point, it is important to focus on the
chosen parts in order to find out how well or not the system works performing
the following steps. To prove the system is at least currently functional, the
beam alignment techniques are done to build up the basic structures needed by
the system.
3-4 Alignment procedure
There are many kinds of beam alignment techniques. Some techniques
30
use very simple methods to deliver the laser beam and others use high-tech
equipment to achieve the purpose of beam alignment. One of the easiest
alignment techniques, manual alignment, is used to align the auto-controlled
scanning system. No matter how simple a technique is used, the goal is to
deliver the beam precisely to the target and to match the design performance.
Before any alignment begins, the factors that affect laser alignment while
performing the alignment steps are summarized.
1. The laser beam must be parallel to each travel axis to achieve its maximum
accuracy.
2. The alignment should begin from the laser head and move out one
component at a time until the last component on an axis is aligned with the
laser beam target aperture.
3. The angle of laser beam can be aligned by moving the laser head or
adjusting the beam plane level.
4. The reflected laser beam can be aligned by adjusting a beam splitter.
5. The angular direction of the beam transmitted straight through a beam
splitter will not be changed by adjusting that component.
6. The retroreflector does not change the angular direction of the beam. The
laser beam remains parallel to its original path.
7. On two-dimensional X-Y coordinates, the first axis is the one that needs its
angular direction adjusted to receive the beam from laser head. When the
first axis and laser head are aligned, the rest of angular adjustment required
by the other axis is accomplished by rotating an optical component.
8. The laser beam path should be kept horizontal or vertical for ease of optical
layout and alignment.
31
9. Make sure all components are set up on the plane and their direction is
parallel or perpendicular to the stage plane.
10. Before installing the optics, make sure all beam paths bend in an optical
square.
The principle of alignment is simple: it delivers a laser beam to a specific
point. The laser beam is one specific visible color or wavelength. Typically,
a red or green colored laser diode is used as the reference beam.
In this case, a manual method is used to perform the laser beam delivery
alignment, because the simplest is the best. Besides, while the
auto-controlled scanning system needs care concerning the galvo scanners, its
optics delivery method is not complicated; therefore, using a simple method
can make the system cost less. Figure 3.1 demonstates the simple way of beam
alignment [24].
32
Figure 3.1 Beam alignment
33
Chapter 4 Assembly and Verification
4-1 Assembly concept
In order to complete the auto-controlled scanning system (in Pictures 4.1
and 4.2), the final assembly steps are described. This system should at least
include an initial mirror to provide an entrance for the laser beam, a final mirror
which conducts and projects the laser beam onto the desired treatment area, and
a set of adjusting optics which are set between the first mirror and the final
mirror. Also, the adjusting mirror set could also make the first and final
mirrors adjust different angles, and correspond with each other from start to end.
Picture 4.1 Auto-controlled scanning system – view 1
34
Picture 4.2 Auto-controlled scanning system – view 2
Between the initial mirror and the adjusting set, there are also the
attenuation lens and the distributing lens. Furthermore, a reflecting mirror is
set between the initial mirror and the adjusting set, to reflect the laser beam to
the dynamometer. In the corresponding route from where the laser beam
reflects from the final mirror, there’s a camera placed to photograph the desired
treatment area. Thus, through this brand-new system, when the first and final
mirrors adjust different angles and finally correspond with each other from start
to end, the laser beam can pass through the optical components, and finally be
conducted and projected precisely on the desired treatment area. That is to say,
the defects from manually controlled surgeries are avoidable and the goal of
automatically controlling the therapy is attainable.
Through the computer, a camera can not only provide the operator with a
convenient way to examine and choose the desired treatment area, but it can also
35
transfer the image to the computer to get the coordinates of the treatment area.
This provides the controlling data for first and final mirrors to make angle
adjustments. The auto-controlled laser system can be more fully understood
through the following examples tied in with the attached figures.
4-2 Assembly procedure
This section starts the step by step process used to construct the designed
system. Please compare the steps with Figure 4.1 and Figure 4.2, which show
the positions of all components described below. The initial reflecting mirror 1
is set on the plate. Set in the path of the reflected route from the initial
reflecting mirror 1, the components are set up in the following order.
First is a pin hole 60, and its stand 6, through which the laser beam passes.
Second, behind pin hole 6, attenuator 4 is set up on a fixed head 42 and is driven
and rotated by a stepping motor 41. Third, the reflecting mirror 5 is fixed on
stand 51 and is rotated by motor 52. Fourth, a divergence lens 7 is set up
behind reflecting mirror 5, followed closely by another stand 6 with a pin hole
60. Fifth, an adjusting mirror set 3 is set right behind the second pin hole set;
this adjusting mirror set 3 is composed of two corresponding mirrors which are
mirror 31 and mirror 32, in that order. Mirror 31 and mirror 32 are
individually driven by galvo 33, and rotate to different angles. Sixth, and last,
a final reflecting mirror 2 is set up on the light reflecting route of second mirror
32; simultaneously, a camera 8 is set up on the reflecting route of the final
reflecting mirror 2; hence, camera 8 can photograph the object along the route of
reflecting mirror 2. Although not mentioned earlier, a power meter 9 is also set
on the reflecting route of reflecting mirror 5.
36
4-3 Verification
After explaining the general construction of the device, its function is
analyzed below (in Figures 4.2 and 4.3, and Table 4.1). First, the system turns
attenuator 4 and reflecting mirror 5 from vertical to horizontal. The laser beam
passes through initial reflecting mirror 1 and into pin hole 60. Second, the
beam then passes through attenuator 4 where the beam’s luminous intensity is
adjusted. The beam then hits reflecting mirror 5 and is reflected to power
meter 9 (see movement situation 1 in Figure 4.3), where its intensity is once
again adjusted after being measured by power meter 9. Third, after the
intensity is properly adjusted, mirror 5 is rotated back to its normal position so
that the beam projects onto distributing lens 7 (as Figure 4.2 and Figure 4.4,
movement situation 2 show), so the beam can be changed from centralizing to
distributing. Finally, after being distributed, the beam passes through another
pin hole 60 to start a series of reflections, from mirror 31, to mirror 32, to final
mirror 2, until finally the laser beam is projected onto the intended treatment
area [25].
In short, this new system calculates the size of the intended treatment region,
and sections the region into many coordinates for the entire therapy when it
receives the image photographed by camera 8. Then, it conveys the
coordinates to the drive units, and drives mirror 31 and mirror 32 to adjust
angles based on the calculated coordinates; thus, the beam can be projected on
every coordinate. The whole treatment is controlled automatically.
It’s not only safe, fast, and highly efficient, but also avoids lapses due to
manual operation; at the same time, the eye-damage caused by strong laser
luminosity could be minimized since the operator no longer has to look at the
37
treatment area directly.
Description of the Drawings:
Figure 4.1: the 3-D structure of this new invention.
Figure 4.2: the 3-D structure of another direction.
Figure 4.3: the top view of movement situation one.
Figure 4.4: the top view of movement situation two.
Table 4.1 Parts description
Description of the Preferred Embodiment:
1. Initial reflecting
mirror
3. The set of adjusting
mirrors
31. First mirror
32. Second mirror 33. Galvo 4. Attenuator
41. Stepping motor 42. Fixed head 5. Reflecting mirror
51. Shutter stand 52. Motor 6. Pinhole stand
60. Pin hole 7. Divergence lens 8. Camera
9. Power meter 2. Final reflecting mirror none
38
Figure 4.1 The 3-D structure of this new invention
39
Figure 4.2 The 3-D structure from another direction
40
Figure 4.3 The top view of movement situation 1
Figure 4.4 The top view of movement situation 2
41
4-4 Target area control
After showing the system construction, we now take a look at how the
whole system works and the flow chart of the image selection. There are two
industrial uses PCs (IPC) in the system: one is a DOS based system; the other
is a Windows system. The DOS IPC is used to control the galvo scanner
system driver broad and communicate with the Windows IPC. The Windows
IPC is mainly used to control the laser source and the touch screen panel
monitor used to select and process the camera-grabbed image data. The two
IPCs work together to simultaneously operate the laser trigger and the driver
motions. The schematic diagram of the system is showing in Figure 4.5 for
reference.
Communication
Laser Head
Frame
Grabber
Touch
Panel
Driver
Laser
beam
Camera
Scanner
IPC IPC
Figure 4.5 Schematic diagram of the system
42
The flow chart in Figure 4.6 shows the procedure as the camera grabs the
image and displays it on the screen. The user or operator selects the surgery
regions so that the computer can calculate its scanning area and treatment time.
The scanner performs the actual operation only while the operator is pushing
the surgery footswitch.
Grab/Display Image
Select Surgery Regions
Compute Scanner Locations
Control Scanner
Start Surgery
Figure 4.6 Flow chart
Before starting the treatment, the user calibrates the galvo position by the
small circle, in Picture 4.3, and large circle, in Picture 4.4; then test the center
cross calibration, in Picture 4.5, and each point of the treatment area
calibration, in Picture 4.6, to make sure the galvo is recognized and saved by
computer.
43
Picture 4.3 Small circle calibration
Picture 4.4 Large circle calibration
44
Picture 4.5 Cross calibration
Picture 4.6 Treatment area calibration
45
A basic example is provided to illustrate how the concept works. The
letter “A” is input to the screen. The operator selects the “A” shape as the
surgical region. The computer calculates the area of the “A” shape and
determines the time needed to complete the surgery. The operator presses the
footswitch until the system automatically finishes the job and the letter “A”
appears on the target, as seen in Picture 4.7.
Picture 4.7 Operation demonstration
Following that example, a patient’s colorful psoriasis picture is placed in
46
front of the working device. The image system is then used to manually
select the lesions to test its function. Pictures 4.8 and 4.9 present the results of
such tests.
Picture 4.8 Colorful psoriasis – test 1
Picture 4.9 Colorful psoriasis – test 2
47
Chapter 5 Conclusion
5-1 Features
This auto-controlled laser scanning system for dermatology treatments has
already been completed, yet the whole system for human skin applications still
needs clinical studies to prove its value.
It is distinguishing the industrial purposes from the medical purposes of
the system. Once the system is permitted to perform surgeries, it will
perform features that the other competitors do not have, which are:
1. Delivers the laser energy specifically to the lesion site via a scanning spot
laser beam delivery system for automatic treatment.
2. The tiny laser spot size (0.49cm²) allows for precise and selective
treatment.
3. The treatment area image recognition system plus the flying spot laser
beam delivery system provide incomparably precise and selective
treatments.
4. MED tests and Doses options are installed in the system for effective
treatments.
Hopefully the system can assist doctors and patients for better solution.
Although the auto-controlled laser scanning system was originally designed
for dermatology purposes, the applications of the system are not supposed to
be limited in this medical field.
48
5-2 Future development
In the future development of the system, there are some ideas that could
make the whole device more convenient or user friendly. These can be
discussed from both software and hardware viewpoints, and from the potential
applications based on the image system.
1. For the software part, combining the two IPCs (DOS and Windows) into
one computer with more efficient upgrades, could save on cost. It is possible
to replace the DOS by the Windows IPC, however, during the software test,
the DOS system triggered the laser with no time delay, but the Windows
system had a time delay. This would cause problems during real time
treatment when the laser beam delivery to the target could be delayed by a
couple of seconds. The auto-controlled scanner system is combined with the
image system which currently uses a touch panel screen with the user painting
and drawing the skin area.
The possibility of an automatic, computer-controlled system used to
isolate the treatment area by identifying the unhealthy lesions is being studied.
Unhealthy lesions can be identified as different from healthy skin tissue by
identifying changes in the skin color or skin texture. In other words, the
doctor’s only job in the future would be to provide confirmation from the
monitor screen after the computer selected the treatment region for one or
more lesions, select the energy level and doses, and then push the footswitch to
complete the treatment.
49
2. For the hardware part, the auto-controlled laser scanning device is
installed and fixed in one place without moving the plane and controlling the
scanner angle to target. Although the device can only lift up and down so far,
but there is a possibility of letting the device shift right to left in front of the
target, so the patient can stand still or lie down and wait for treatment until
finish. Again, the problem faced is that the laser cannot move around.
The typical excimer laser is heavy and needs a gas tank to supply the gas
into the laser. The laser needs to cooperate with the scanner without using an
optical fiber which would diminish the energy, and it needs calibration
whenever the laser is moved.
The second thought is to replace a galvo with a stepping motor, because
the galvo rotation speed is higher than the system requires and the stepping
motor can handle a bigger mirror. The treatment area, therefore, may become
bigger and save more time during the surgery.
3. The potential applications of the image system obtain image
identification of license plates, human face recognition, traffic condition
real-time feedback for driving safety, and the replacement of the laser source
from 308nm to various wavelengths for applications requiring different kinds
of laser treatment.
The monitor and CCD camera uses for crime tracking usually have a
problem with identifying license plates. If the image system can modify the
gray level image from 0 to 255 and find an easy way to identify the license
plate number, there might be a chance to catch the criminal quickly and
50
prevent the next incident. This can also be applied to human face
identification for criminals or searching for missing people.
Driving safety is one of the major issues for human life with thousands of
people dying in car accidents every year. Some luxury sedans, like
Mercedes-Benz, Lexus, and BMW, have systems to prevent car crashes from
the rear, but the system function is limited to use during cruise mode, not all
the time.
The image system has an aiming beam sensor to detect the working
distance, and to make sure the laser power density and dosage can be precisely
delivered to the target. It can also detect if the distance is within safety limits
and feedback this information to the computer to make the decision whether to
trigger the laser or not. The image system has the potential to be modified as
a safety guard to prevent major car crashes.
For the medical laser device, the most interesting thing to do is change the
laser wavelength for applications involving different diseases or procedures.
Basically, the whole auto-controlled scanning system can be considered as
separate modules, as the system schematic diagram in Figure 4.5 shows. All
that needs to be done is put in a different laser source and adapt the optics to
the new wavelength. By doing it this way, a lot of research and development
time can be reduced and more useful laser treatment devices can be created.
51
Appendix A
Other dermatology laser patent analysis list
Number Patent name Patent
number and
date
Patent scope
1 Multibeam laser for skin
treatment
US200608
4953
2006-04-20
For skin beauty,
not relevant
2 Improved hand-held laser
device for skin treatment.
MXPA0400
1537-
2004-10-27
Portable beauty
laser, not
relevant
3 Methods for treatment of human
skin damaged by laser treatment
or chemical peelings and
compositions useful in such
methods
US200510
0592 -
2005-05-12
Not relevant
4 A topical agent containing niacin
for application to the skin prior to
luminous treatment
WO20040
87093 -
2004-10-14
Not relevant
5 Laser therapy device for the
treatment of skin diseases
US200418
1267 -
2004-09-16
Optical fiber
treatment, no
infringement
6 Method and apparatus for skin
treatment using near infrared
laser radiation
US200501
5077 -
2005-01-20
Skin removal,
not relevant
7 Hand-held apparatus for skin
treatment with intensive light
WO20040
10884 -
2004-02-05
Portable beauty
laser, not
relevant
8 Combined device for cooling the
skin and suction removal of
smoke and ejected skin particles
generated during laser treatment
of the skin, has an open conical
design that ensures that both
functions are reliably fulfilled
DE103072
60 -
2003-08-21
Not relevant
9 Skin treatment device JP200421
5837 -
2004-08-05
Low
temperature
skin treatment,
no infringement
52
Number Patent name Patent
number and
date
Patent scope
10 Skin diagnosis system, electronic
treatment apparatus
JP200414
1259 -
2004-05-20
Skin diagnosis,
not relevant
11 Methods for treatment of human
skin damaged by laser treatment
or chemical peelings and
compositions useful in such
methods
US200301
2762 -
2003-01-16
Not relevant
12 Laser skin treatment device with
control means dependent on a
sensed property of the skin to be
treated
GB238175
2 -
2003-05-14
Not relevant
13 Treatment of acne vulgaris skin
condition by irradiation with light
of specific wavelengths to target
specific chromophores &
stimulate collagen production
GB236802
0 -
2002-04-24
LED skin
treatment，not
relevant
14 Composite beauty skin treatment
device
JP200211
3116 -
2002-04-16
Not relevant
15 Probe for skin high frequency
treatment
US649770
2 -
2002-1
2-24
Not relevant
16 Automatic firing apparatus and
methods for laser skin treatment
over large areas
WO01265
73 -
2001-04-19
Not relevant
17 Laser skin treatment apparatus EP105745
4 -
2000-12-06
Optical fiber
treatment, it can
measure skin
temperature
18 Laser optics positioning element
for skin treatment
EP102387
4 -
2000-08-02
Not relevant
53
Number Patent name Patent
number and
date
Patent scope
19 Device for hand and foot
treatment and care has a medical
laser for removal of skin or nail
material with such treatment
resulting in very little generation
of dust from skin or nail parts
and therefore being much more
hygienic
DE199520
45 -
2001-08-23
Not relevant
20 Laser for skin treatment WO00710
45 -
2000-11-30
Auto focus
laser, no
infringement
21 Skin treatment process using laser US603668
4 -
2000-03-14
Skin removal
laser, no
infringement
22 Method for non-invasive wrinkle
removal and skin treatment
US607729
4 -
2000-06-20
Not relevant
23 Enhanced laser skin treatment
mechanism
US598051
2 -
1999-11-09
Not relevant
24 Laser treatment/ablation of skin
tissue
US608658
0 -
2000-07-11
Not relevant
25 Laser dermal implants for the
treatment of facial skin
depressions
US581709
0 -
1998-10-06
Not relevant
26 Device for cooling skin during
laser treatment
EP082771
6 -
1998-03-11
Skin removal
laser, no
infringement
27 Laser application device for skin
treatment
JP110471
46 -
1999-02-23
Skin removal
laser, no
infringement
28 Skin treatment process using laser WO96415
79 -
1996-12-27
Not relevant
29 Method of treatment of skin
lymphomas
RU212853
3 -
1999-04-10
Not relevant
54
Number Patent name Patent
number and
date
Patent scope
30 Skin treatment process using laser US581708
9 -
1998-10-06
Not relevant
31 Laser treatment method for
removing pigment containing
lesions from the skin of a living
human
US529027
3 -
1994-03-01
Optical fiber,
no infringement
32 Device for treatment of undesired
skin disfigurements
US532061
8 -
1994-06-14
Not relevant
33 Laser treatment method for
removing pigmentations, lesions,
and abnormalities from the skin
of a living human
US521745
5 -
1993-06-08
Not relevant, no
infringement
55
Appendix B
Wavelight laser technology patents
Number Patent name Patent number and date
1 Fiber laser arrangement EP1650839 - 200
6-04-26
2 Laser system with soild laser heads WO2006034783
- 2006-04-06
3 Device for producing a white light ES2248534T - 20
06-03-16
4 Rapid wavefront measurement WO2006024504
- 2006-03-09
5 Device for ophthalmologically
treating the eye using a fixation light
beam
ES2245684T - 20
06-01-16
6 Laser system for corneal grafting ES2245384T - 20
06-01-01
7 Method of generating a control
program for a device for
photorefractive corneal surgery of
the eye
US2005187540 -
2005-08-25
8 Method for the minimal-to
non-invasive optical treatment of
tissues of the eye and for diagnosis
thereof and device for carrying out
said method
WO02076355 - 2
002-10-03
9 Method for producing a control
program for a device used for
performing corneal eye surgery
US2003105457 -
2003-06-05
10 Device for medical treatment of the
eye using laser radiation US6755817 - 20
04-06-29
11 Device used for the photorefractive
keratectomy of the eye using a
centering method
US2002128634 -
2002-09-12
12 Device for photorefractive cornea
surgery in higher-order visual
disorders
US6530917 - 20
03-03-11
13 Dispositivo para un treatmento
medico del ojo con radiacion laser. ES2231210T - 20
05-05-16
56
Number Patent name Patent number and date
14 Device for treating bodily substances US6328732 - 20
01-12-11
15 Device for medical treatment with a
light source WO9962442 - 19
99-12-09
16 Surgical vitrectomy instrument has
aspiration duct containing radiation
conductor, chamber with at least
three openings
DE19842799 - 2
000-03-23
17 Device and method for the removal
of body substances US6027493 - 20
00-02-22
18 Laser device for treatment of patient
skin and other dermatological
processes
DE19811627 - 1
999-09-23
19 Arrangement for treating bodily
substances DE19734732 - 1
998-06-18
20 Surgery system for vitreous humour
of eye DE19720660 - 1
998-11-19
21 Intra-ocular cataract surgery device DE19702353 - 1
998-04-16
22 Material processing arrangement
with pulsed laser e.g. for eye surgery DE19702335 - 1
998-08-27
57
Appendix C
InPro Innovations patents
Number Patent name Patent number and
date
1 Process for interior coating of hollow
bodies DE59912989D -
2006-02-02
2 Method for connecting pieces
accessible only from one side and
assembly of such pieces
DE50302005D -
2006-01-26
3 Method and device for determining
the resistance of sheet metal to
alternating bending loads
EP1577659 - 20
05-09-21
4 Method and device for forming of
undercuttings when joining
superimposed work pieces, in
particular coated and/or varnished
metal sheets
EP1249286 - 20
02-10-16
5 Process for welding thermoplastic
joining parts using laser diode
radiation
EP1238781 - 20
02-09-11
6 Teach-in generation of programs for
component 3-dimensional solid state
laser processing involves converting
laser diode radiation incidence point
image to bitmap with frame grabber
card
DE19961625 - 2
001-07-05
7 Device for plasma polymerizing
batches of hollow work pieces in
plural pieces processing
EP1054432 - 20
00-11-22
8 Process for making multifunctional
plasma polymerized layers on plastic
parts
EP1018532 - 20
00-07-12
9 Docking process for welded sheet
plates being deformed by internal
high pressure
DE19812884 - 1
999-09-23
10 Process for geometry recognition and
tracking during thermal treatment of
elements by means of laser beam
EP0904886 - 19
99-03-31
58
Number Patent name Patent number and
date
11 Pump lamp exchange device for solid
laser DE19709660 - 1
998-09-24
12 Impermeable layer on inside wall of
vessel especially plastic fuel tank DE19700426 - 1
998-07-16
13 Method and arrangement for surface
treatment with temperature control,
particularly for superficial hardening
with laser radiation
EP0836905 - 19
98-04-22
14 Method of hardening the surface of a
work piece using a beam, particularly
a laser beam and device for executing
this method
EP0822027 - 19
98-02-04
15 Process for welding tinned metal
sheets, using a solid state laser EP0800888 - 19
97-10-15
16 Laser beam welding seam depth
control DE19605888 - 1
997-08-21
17 Joining motor vehicle body
components DE19604081 - 1
997-08-07
18 Monitoring protective glass of laser
welding optics DE19605018 - 1
997-08-07
19 Method for quality testing of
semi-products, modules and
components with ultrasounds
EP0770867 - 19
97-05-02
20 Process for plasma coating a plastic
object with multifunctional layers EP0739655 - 19
96-10-30
21 Method for creating low ohmic
contact areas on thermoplastic
articles filled with long steel fibers
EP0728571 - 19
96-08-28
22 Method for producing thermoplastic
objects with plasma-suitable surfaces EP0722823 - 19
96-07-24
23 Method for the decomposition and
separation of recyclable
three-material composite components
by type
EP1036596 - 20
00-09-20
24 Process and device for welding sheet
metal construction elements, in
particular tinned sheet metal elements
by means of laser beams
EP0687519 - 19
95-12-20
59
Number Patent name Patent number and
date
25 Process for pre- or post-treatment of
components welding seam to be
executed resp. executed
EP0688627 - 19
95-12-27
26 Method and device for coating
electrostatically and/or pneumatically
a conductive substrate with a liquid
coating product
EP0695582 - 19
96-02-07
27 Method of manufacturing objects or
preforms using polymers as raw
materials, especially for plastic fuel
tanks.
EP0677366 - 19
95-10-18
28 Process and device for monitoring the
welding depth in work pieces during
laser beam welding.
EP0674965 - 19
95-10-04
29 Method of regulating the force
applied to sheet during deep drawing DE4339153 - 19
95-05-24
30 Method for determining reference
variables for process systems,
especially for a process controller
DE4303561 - 19
94-08-11
31 Method for making products by force
or pressure influenced drawing
processes.
EP0589066 - 19
94-03-30
32 Process and device for positioning and
controlling a high energy source, in
particular a laser relative to a work
piece.
EP0531558 - 19
93-03-17
33 Method of correcting regulation
parameters in a process control
system, especially to maintain the
dynamic range (regulating range) of
the process control system during the
course of the process and device for
implementing the process.
EP0489130 - 19
92-06-10
34 Process and device for automatic
determination of parameters for
process control systems with unknown
transfer behavior, in particular for
process control systems for resistance
spot welding.
EP0452440 - 19
91-10-23
60
Number Patent name Patent number and
date
35 Cruciform planar specimen for
biaxial materials testing DE3914966 - 19
90-07-12
61
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