2
FIELD OF THE INVENTION
[0001]The present invention relates generally to an illumination control system,
and more particularly to an illumination control device for an endoscopic
light source.
BACKGROUND OF THE INVENTION
[0002]Minimally invasive procedures or surgeries (MIP or MIS), including
endoscopic, laparoscopic, endoscopically-assisted, or laparoscopically-
assisted procedures, are known and offer benefits to a patient such as
Imited incisional trauma, decreased pain, limited scars, decreased
hospitalization, and earlier return to a normal functional state. To perform
such procedures, typically an external light source coupled to an optic
fiber and endoscope is used to illuminate the operative space. Typically, a
control over the illumination intensity is desired to improve and adjust the
visualization of the site as per the needs of the surgeon, operator and/or
the practitioner.
[0003]Several techniques and devices have been employed to control the
illumination intensity such as controlling the feeding current/voltage
magnitude or phase to the light source, rotatable shutters, optical
attenuator/absorptive devices, optical diaphragms, and slit controls, and
the like. There are drawbacks, however, associated with these techniques,
such as change in color temperature, ringing, uneven distribution of light,

3
limited range of illumination control, grainier control of the illumination
intensity, and change in angle of entrance of the light beam.
[0004]To overcome most of the above-mentioned drawbacks, various medical
devices are being developed for controlling the illumination intensity of the
endoscopic light sources. One such control device establishes the use of a
circular disc with varying aperture/opening. The aperture is located
between the light source and the entrance plane of the fiber optic cable.
Rotation of the disc varies the aperture, thereby controlling the
illumination zone at the entrance plane of the fiber optic cable. Another
device employs a rotating disc with two concentrically placed bands,
wherein the first band comprises an open portion and second band
comprising slots whose width and spacing successively change such that
with rotation of the disc, the light transmitted by the second band
gradually increases, being additive to the light transmitted by the open
portion of the first band. Other devices provide multiple discs
arrangements for controlling the illumination intensity.
[0005]The above-mentioned devices, however, have certain drawbacks that
need to be overcome. Firstly, these devices may results in ringing or
uneven distribution of illumination intensity. Further, most of these control
devices provide a limited level of control over the illumination intensity.
[0006]In the light of the above discussion, Applicant's have recognized the
desirability of an illumination control device that overcomes one or more
of the limitations of the devices mentioned above, while keeping one or

4
more of their advantages. Hence, the control device should be simple in
design and should provide finer control of illumination intensity. Furthe.,
the device should be easier to operate and should not cause uneven
distribution of illumination intensity.
OBJECTS OF THE INVENTION
[0007]It is therefore an object of the invention to propose an illumination control
device in an endoscopic imaging system, which eliminates disadvantages
of the prior art.
[0008]Another object of the invention is to propose an illumination control device
in an endoscopic imaging system, which eliminates the problem of uneven
distribution of illumination intensity by the device.
[0009]A further object of the invention is to propose an illumination control
device in an endoscopic imaging system, which is capable of providing
finer control on the illumination intensity.
[0010]A still further object of the invention is to propose an illumination control
device in an endoscopic imaging system, which is simple, easy to operate
and cost-effective.

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SUMMARY OF INVENTION
[0011]Accordingly there is provided an illumination control device in an
endoscopic imaging system, the system comprising a light source
subassembly having at least one light source and a reflector, the reflector
transforming the light originated from the light source into a focused
beam of light; a power supply module to provide power to the light source
including several other modules of the system; the illumination control
device disposed between the light source and an optic port, and controls
the intensity of the focused beam of light and allows the controlled beam
of light to pass though the optic port; a fibre optical cable transmitting the
light beam from the optic port to an endoscope and illuminates the
examination site; a camera unit receiving the light reflected from the site
via the endoscope and converting the reflected light to video/image
signals; and an electronic subassembly for modulating and processing the
video signals received via a camera connector and allows display of the
video via a display unit, the device comprising; a control member
connected to a motion transmission means; a driving means connecting
the motion transmission means govern the movement of the control
member; an elongated limiting member to limit the movement of the
driving means which in turn limits the movement of the control member,
wherein, the control member comprises; an aperture formed in a carrying
or bearing member, the movement of the aperture corresponding to a
movement of the control member thereby controlling the illumination
intensity at the examination site; and a grating, with varying opacity along

6
the guiding curve, coupled to the aperture wherein the aperture vary in size
along the guiding curve up to a predefined length.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0012]FIG. 1 illustrates a functional block diagram of an imaging system wherein
the embodiments of the present invention can be practiced;
[0013]FIG. 2 illustrates an exploded view of the illumination control device, in
accordance with an embodiment of the present invention;
[0014]FIG. 3 illustrates the engagement of a limiting member and a driving
means of the illumination control device, in accordance with an
embodiment of the present invention;
[0015]FIG. 4 illustrates the control member of the illumination control device, in
accordance with an embodiment of the present invention; and
[0016]FIG. 5 illustrates the control curve of the illumination control device, in
accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0017]Although the present invention will be described in conjunction with some
embodiments as depicted in the figures, a person skilled in the art will

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easily recognize that numerous additional embodiments will be well within the
scope of the present invention, wherein the scope is defined by the claims
provided. Hence, the detailed description that follows is intended merely to
illustrate the present invention, and is not intended to limit the scope and spirit
of the claimed invention in any way. In this regard, certain definitions for the
terms used in the claims are appropriate to ensure that the reader will not think
to limit the scope of these terms to the specified preferred embodiments
described in this detailed description. These definitions are given by way of
example only, without limitation.
[0018]lhe terms "fiber optics" and "fiber optic cable" as used herein are
intended to typically refer to flexible optical conductors comprising a
multiplicity of light conductive fibers, e.g. glass fibers, in the form of a
bundle or strand; generally, the bundle includes an adhesive, matrix or
the like for interconnection of the fibers, and a sheath, sleeve or the like is
arranged around the fiber bundle; the bundle ends are arranged in
planes, generally by grinding vertically to the axes of the fibers; when
used for illumination of a cavity, one of the planes is arranged near a light
source and referred to as "entrance plane" while the other plane is placed
near the site that is to be illuminated and is referred to as the "exit plane."
[0019]The term "light source" as used herein refers to light source producing
light or a light beam. The light source can be a cold light source, wherein,
the light or the light beam contains only a negligible amount of he?t
radiation, that is, only very little radiation in the infrared range of the
spectrum, if any. The light sources may also be chosen from other kinds

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of light sources. Various light sources are known to those skilled in the art, such
as a halogen light source, xenon light source, metal halide bulb, LED, tungsten
filament bulb, arc light source and the like. Further, the light source may
sometimes include an integrated reflector for providing a focused beam of light.
[0020]Once the scope of some of the critical terms has been defined, to get a
more complete understanding of the present invention, a detailed
description of the various embodiments of the present invention in
conjunction with the illustrations, is provided below.
[0021] Referring to FIG. 1, an illustration of an endoscopic imaging system 100
wherein the application of an embodiment of the present invention is
illustrated. The imaging system 100 typically includes a light source
subassembly 110, a cooling module 120, a power supply module 130, an
electronic subassembly 140, a camera unit 150, an optic port 160, a fiber
optic cable 170, a camera connector 180, an endoscope 190, and an
illumination control device 200. The light source subassembly 110 includes
a light source 112, a reflector 114, a light source mounting 116, and a
heat sink 118. The light source 112 and the reflector 114 are attached to
the light source mounting 116. The heat sink 118 is coupled to the light
source mounting 116. The heat sink 118 is provided to enhance the
cooling effect of the cooling module 120. The light source is powered by
the power supply 130. The power supply module 130 may also supply
electrical power to other modules of the system 100 such as the cooling
module 130, camera unit 150, and the electronic subassembly 140.

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[0022]The imaging system 100 functionally comprises two essential flows, the
first being the flow of light for illuminating from the light source (112) to
the site to be examined/manipulated/operated. The second being the flow
of the video signals/images from the examination site to the display. The
following paragraphs explain these flows and associated system modules.
[0023]The light originating from the light source 112 is transformed into a
focused beam of light by the reflector 114. The focused beam of light
passes through the illumination control device 200, which is located
between the light sourcell2 and the optic port 160. The illumination
control device 200 controls the intensity of light beam that passes through
the optic port 160. The illumination control device 200 is the focus of the
present invention, and is described in details in conjunction with Figure2.
The light beam is thereafter, transmitted through the fiber optic cable 170
to the endoscope 190. The light beam passes through the endoscope
190, and illuminates the site to be examined/manipulated/operated.
[0024]Once the site is illuminated, the reflected light passes through the
objective lens of the endoscope 190 and is transmitted to the camera unit
150. The camera unit 150 converts the reflected light to video/image
signal. Thereafter, the video signals are passed to the electronic
subassembly 140 through the camera connector 180. The video signals
are modulated and processed by the electronic subassembly 140. The
electronic subassembly 140 also includes output ports where a video
display can be connected to view the video images from the examination
site.

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[0025]Referring now to FIG.2, an exploded view of the illumination control
device is illustrated. The illumination control device 200 includes a control
member 210, a mounting block 220, a motion transmission means 230, a
driving means 240, an elongated limiting member 250, and at least two
coupling members 260 and 270. The second coupling member 270
couples the control member 210 to the mounting block 220. The second
coupling member 270 also connects the motion transmission means 230
to the control member 210. The motion transmission means 230 is
further, coupled to the mounting block 220 by the first coupling member
260. The first coupling member 260 also connects the driving means 240
to the motion transmission means 230. In various embodiments of the
present invention, the first and second coupling members 260 and 270
are moveably or rotatbly coupled to the mounting block 220 and the other
components are attached to the first and second coupling members 260
and 270 using screws, keyway-pin arrangement, hole-pin arrangements,
glue, and the like. Hence, the movement of the driving means 240
governs the movement of the control member 210. However, the
elongated limiting member 250 is provided to limit the movement of the
driving means 240. As shown in the figure 2, the elongated limiting
member 250 is attached to the mounting block 220. Further, the
elongated limiting member (250) engages with one or more planar
members (not shown in Figure 2) to limit the movement of the driving
means 240, as explained in conjunction with FIG. 3.

11
[0026]In an embodiment of the present invention, as illustrated in Fig. 2, the
control member 210 is in form of a circular disc. The disc is centrally
attached to the second coupling member 270 by means of screw. In
various embodiments of the present invention, other means of attaching
the control member 210 to the second coupling member 270 can be used,
such as welding, glue, rivet, nut and bolt arrangement, keyway-pin
arrangement, hole-pin arrangement, non-circular shaft and hub, spline
shaft and hub arrangement, and the like.
[0027]The second coupling member 270 is in form of a shaft rotatably coupled
to the mounting block 220 by means of bearings, bushings, clips and the
like. The second coupling member 270 is also coupled to the motion
transmission means 230. In an embodiment of the present invention, the
motion transmission means 230 is a belt drive, as illustrated in Fig. 2. The
belt drive includes a set of toothed gears and a driving belt connecting the
gears. One of the toothed gears is attached to the second coupling
member 270. The other toothed gear is attached to the first coupling
member 260. The embodiment of the present invention illustrates the use
of a belt drive for motion transmission, however, numerous other motion
transmission mechanism and their variations may occur to those skilled in
the art, such as, rack and pinion arrangement, a gear drive, a belt-pulley
arrangement, frictional drives, pneumatic transmission system, hydraulic
transmission system magnetic transmission systems and the like.

12
[0028]The first coupling member 260, as shown in Figure 2, is a shaft rotatably
coupled to the mounting block 220 by means of a bearing, bushing, dips
and the like. As mentioned above, the motion transmission means 230 is
also attached to the first coupling member 260. Further, the driving
means 240 is also attached to the first coupling member 260. In an
embodiment of the present invention, the driving means 240 is a manually
actuated knob, wherein the knob is fixed to the coupling member by
means of screws, nut and bolt arrangement, welding, gluing, riveting,
keyway-pin arrangement, hole-pin arrangement, non-circular shaft and
hub, spline shaft and hub arrangement, and the like. In another
embodiment of the present invention, the driving means 240 is an electric
stepper motor combined with a switch to control the motion. Various
other embodiments of the driving means 240 are known to those skilled in
the art, for example, pneumatic, hydraulic, magnetic, and the like.
[0029] Figure 3a and 3b illustrate the engagement of the elongated limiting
member 250 with planar members 302 and 304, respectively. The planar
members 302 and 304 are attached to the driving means 240, therefore,
the engagement of the elongated limiting member 250 with the planar
members 302 and 304, limits the movement of the driving means 240.
Limiting the movement of the driving means 240 limits the movement of
the control member 210. Thus, setting up the range of control of the
illumination intensity. In an embodiment of the present invention, as
illustrated in Fig. 3, the planar members 302 and 304 are placed at 180
degrees with each other. The said placement of the planar members 302
and 304 causes the movement of the driving means 240 to get limited by

13
180 degrees. Hence, the range of movement of the control member 210 is
limited. The range of movement of the control member 210 and the components
of the control member 210 defines the control a user/operator would have over
the illumination intensity. The components of the control member 210 are
described in detail, in conjunction with Figure 4.
[0030]Referring now to FIG. 4, the control member 210 and its components are
illustrated. The control member 210 includes a carrying/bearing member
402, an aperture 404, a grating 406, a centre bore 408, at least two holes
410 and 412. In an embodiment of the present invention, the
carrying/bearing member 402 is shaped like a circular disc. The
carrying/bearing member 402 can be made of composites, metal, alloy,
heat resistant plastic, glass, ceramic, and the like.
[0031]The aperture 404 is a variable slit/opening in the carrying/bearing
member 402, the slit/opening substantially symmetrical about a guiding
curve 414. The aperture 404 is placed between the optic port 160 and
light source 112. Further, as the driving means 240 moves the control
member 210, the aperture 404 moves across the optic port 160. Thus, the
aperture 404 controls the area of the optic port 160 receiving the light
from the light source 112. As the light passing through the optic port 160
is transmitted to the endoscope 190, the movement of the aperture 404
affects illumination intensity at the site of examination. Further, the center
of the optic port 160 follows the guide curve 414 as the control member
210 is moved. In addition, the aperture 404 is equally distributed about
the guiding curve 414. This results in a substantially symmetrical

14
distribution of light across the optic port 160. In an embodiment of the present
invention, as illustrated in Fig. 4, the aperture 404 is in form of a sickle. The
sickle shape provides a substantially symmetrical distribution of the light intensity
across at the optic port 160. The width of the aperture 404 increases until a first
point 416, and thereafter becomes constant. The width at the first point 416 can
be greater than, or equal to the diameter of the optic port 160. As shown in the
FIG. 4, the width of the aperture 404 is equal to the diameter of optic port 160
at a second point 418. The second point 418 comes before the first point 416
moving clockwise along the guiding curve 414. In an embodiment of the present
invention, the first point 416 and second point 418 may coincide. Since, the
limiting dimension is the diameter of the optic port 160, the illumination intensity
is independent on the aperture 404 as the width of aperture increase beyond the
width at the second point 418.
[0032]In various embodiment of the present invention, the aperture 404 can
have different shapes within the scope of the invention. In addition,
different shapes of the aperture 404 may be desired corresponding to
various embodiments of the control member 210. For example, in an
embodiment of the present invention, wherein the control member 210 is
a rectangular plate, the aperture 404 can be an isosceles triangle.
[0033]The control member 210 also includes grating 406, which occupies the
aperture 404. The opacity of the grating 406 varies along the guiding
curve 414. In an embodiment of the present invention as illustrated in Fig.
4, the grating 406 is a metal plate with circular holes. The pattern of the
holes is varied across the guiding curve 414 to vary the opacity of the

15
grating 406. In various embodiments of the present invention, the opacity of the
grating 406 is varied by varying the spacing between the holes, varying the size
of the hole, changing the shape of the hole, or a combination thereof. The
variation in the opacity of the grating 406 is substantially gradual. However, in
various embodiments of the present invention, the opacity of the grating 406
may be desired to change in an stepwise manner, or a combination of stepwise
and gradual change, and the like. Further, in various embodiment of the present
invention, the circular holes in the grating 406 as illustrated in Fig. 4, may be
replaced by different shapes such as oval, square, rectangular, slit-shape,
triangle, star, cross, and the like.
[0034]Although the Fig. 4 illustrates the grating 406 as a metal plate with holes,
various other embodiments of the grating 406 may be known to those
skilled in the art. For example, the grating 406 may be made up of mesh
wire, glass, plastic, and the like. Also, various other ways of varying
opacity may be known to those skilled in the art, such as etching the glass
or plastic to vary its transparency, and the like.
[0035]In addition, in an embodiment of the present invention, the grating 406
can be combined with filters to vary the characteristics of the light
entering the optic port 160. For example, the filter can be a thermal filter,
an Ultraviolet filter, an Infrared filter, Chromatic filter, or a combination
thereof.

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[0036]In the light of the above description, the illumination intensity control is
dependent on the width of the aperture 404 and the opacity of the grating
406. Referring to the Fig. 4, as we move in a clockwise direction the width
of aperture 404 increases, increasing the illuminated area of the optic port
160. The illuminated area of the optic port 160 continues to increase until
the width of the aperture 404 equals the diameter of the optic port 160,
that is, until the second point 418. Beyond the second point 418, moving
clockwise, the illumination intensity is independent of the width of
aperture 404. The illumination intensity is however still dependent on the
opacity of the grating 406. Hence, before the second point 418,
illumination intensity is controlled by the opacity of grating 406 and width
of aperture 404, but after the second point 418, illumination intensity is
just the function of the opacity of the grating 406. Thus, resulting in a
finer control of the illumination intensity at the lower intensities. In
addition, since the illumination intensity is dependent on more than one
variable, various desired control curves can be realized. The control curve
is the illumination intensity versus the angle of rotation of the driving
means 240. For example, the control curve 500 for the control member
illustrated in FIG. 4 is shown in FIG. 5.
[0037]Hence, the control member 210 has the various advantages over the
above background arts. Firstly, a finer and gradual control of illumination
intensity at lower light intensities and desired control of illumination
intensity at higher intensities. Secondly, a substantially symmetrical
distribution of the light across the optic port and thereby across the fiber
optic bundle. And lastly, an integrated design for analog/stepped control.

17
[0038]While the present invention has been illustrated by description of several
embodiments, it is not the intention of the applicant to restrict or limit the
scope of the appended claims to such detail. Numerous other variations,
changes, and substitutions will occur to those skilled in the art without
departing from the scope of the invention.

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WE CLAIM
1. An illumination control device (200) in an endoscopic imaging
system (100), the system (100) comprising a light source
subassembly (110) having at least one light source (112) and a
reflector (114), the reflector (114) transforming the light originated
from the light source (112) into a focused beam of light; a power
supply module (130) to provide power to the light source (112)
including several other modules of the system (100); the
illumination control device (200) disposed between the light source
(112) and an optic port (160), and controls the intensity of the
focused bean of light and allows the controlled beam of light to
pass though the optic port (160); a fibre optical cable (170)
transmitting the light beam from the optic port (160) to an
endoscope (190) and illuminates the examination site; a camera
unit (190) receiving the light reflected from the site via the
endoscope (190) and converting the reflected light to video/image
signals; and a electronic subassembly (140) for modulating and
processing the video signals received via a camera connector (180)
and allows display of the video via a display unit, the device
comprising;
- a control member (210) connected to a motion
transmission means (230);

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- a driving means (240) connecting the motion
transmission means (230) to govern the movement of
the control member (210);
- an elongated limiting member (250) to limit the
movement of the driving means (240) which in turn limits
the movement of the control member (210),
wherein, the control member comprises;
- an aperture (404) formed in a carrying or bearing
member (402), the movement of the aperture (404)
corresponds to a movement of the control member (210)
thereby controlling the illumination intensity at the
examination site; and
- a grating (406) with varying opacity along the guiding
(416) curve, coupled to the aperture (404); wherein the
aperture (404) vary in size along the guiding curve (416)
up to a predefined length.
2. The device as claimed in claim 1, wherein the motion transmission
means (230) is connected to a mounting block (220) via a first
coupling member (260) and wherein the control member (210) is
coupled to the mounting block (220) via a second coupling member
(270).
3. The device as claimed in claim 1, wherein the driving means (240)
comprising at least two planer members (302, 304).

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4. The device as claimed in claim 1, wherein the aperture (404) is
disposed between the optical port (160) and the light source (112).
5. The device as claimed in claim 1 or 4, wherein the grating (404)
comprises at least two holes (410, 412).
6. The device as claimed in claim 1, wherein the first and second
coupling members (260, 270) are movably or rotatably coupled to
the mounting block (220).
7. The device as claimed in claim 1, wherein the control member
(210) can be configured as a circular disk centrally attachable to
the second coupling member (270), and wherein the second
coupling member (270) can be formed as a shaft rotatably coupled
at a first end to the mounting block (220), and to the motion
transmission means (230) at a second end.
8. The device as claimed in claim 1, wherein the first coupling means
(260) can be formed as rotatable shaft coupled to the mounting
block (220) at a first end, the second end being attached to said
motion transmission means (230).
9. The device as claimed in any of the preceding claims, wherein the
motion transmission means (230) is a belt-drive having at least two
sets of gears, one each set of gear being respectively engageable
to the first and second coupling members (260, 270).

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10.The device as claimed in claim 1, wherein the driving means (240)
can be selected as an electric stepper motor including a switch to
control its motion, and wherein the driving means 9240) is attached
to the first coupling member (260).
11.The device as claimed in claim 1, wherein the planar members
(302, 304) are disposed at 180° apart from each other which
delimits the movement of the driving means (240) to 180°.
12.The device as claimed in claim 1, wherein the carrying or bearing
member (402) can be made of composites metal, alloy, heat-
resistant plastic, glass, ceramic, and the like, and shaped as a
circular disc.
13.The device as claimed in claim 1, wherein the aperture (404) is
equally distributed along the guiding curve (414) so as to achieve a
symmetrical distribution of the light intensity across the optic port
(160).
14.The device as claimed in any of the preceding claims , wherein the
apeture (404) is formed as a sickle, and wherein the width of the
aperture (404) increases until the first point (416), and becomes
constant thereafter.

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15.The device as claimed in claim 1, wherein the grating (406)
comprises one of a metal plate, mesh-wire, glass, plastic, and
wherein the grating (406) can be provided with filters for example
thermal filters, U.V. filters, IR filters, chromatic filters, or a
combination thereof which vary the characteristics of the light
entering the optic port (160).
16. An illumination control device in an endoscopic imaging system as
substantially described and illustrated herein with reference to the
accompanying drawings.

This invention relates to an illumination control device (200) in an endoscopic
imaging system (100), the system (100) comprising a light source subassembly
(110) having at least one light source (112) and a reflector (114), the reflector (114) transforming the light originated from the light source (112) into a focused beam of light; a power supply module (130) to provide power to the light source (112) including several other modules of the system (100); the illumination
control device (200) disposed between the light source (112) and an optic port (160), and controls the intensity of the focused bean of light and allows the controlled beam of light to pass though the optic port (160); a fibre optical cable (170) transmitting the light beam from the optic port (160) to an endoscope
(190) and illuminates the examination site; a camera unit (190) receiving the light reflected from the site via the endoscope (190) and converting the reflected light to video/image signals; and a electronic subassembly (140) for modulating and processing the video signals received via a camera connector (180) and
allows display of the video via a display unit, the device comprising; a control member (210) connected to a motion transmission means (230); a driving means (240) connecting the motion transmission means (230) to govern the
movement of the control member (210); an elongated limiting member (250) to limit the movement of the driving means (240) which in turn limits the movement of the control member (210), wherein, the control member comprises; an aperture (404) formed in a carrying or bearing member (402), the movement of the aperture (404) corresponds to a movement of the control
member (210) thereby controlling the illumination intensity at the examination
site; and a grating (406) with varying opacity along the guiding curve (416), coupled to the aperture (404); wherein the aperture (404) vary in size along the guiding curve (416) up to a predefined length.