Kowa K9L48B, Service Manual, Page: 7 / 60

GG-09001 Edition 1.3
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Optical principals of fundus photography
(See the figure “Principals of Fundus Photography” on Page 7)
Lighting system
①
Observation lamp
⇒
Ring slit
＜
Non-mydriatic photography
＞
Illumination light goes through the infrared permeable filter and filtered infrared light
passes through the non-mydriatic ring slit.
＜
Mydriatic photography
＞
Illumination light goes directly through the mydriatic ring slit.
＜
FA
＞
Illumination light goes through the FA exciter and the excited light with the FA
compatible wavelength passes through the mydriatic ring slit.
②
Ring slit
⇒
Patient’s eye
In all photography modes, illumination light becomes ring-shaped after it passes
through a ring slit and reflected by the perforated mirror. Then the reflected light is
condensed by the objective lens and directed to the fundus.
Observation/Photography system (Patient’s eye
⇒
Finder or Camera)
③
Patient’s eye
⇒
Variable angle lens
Illuminated fundus image is captured by the objective lens and directed though the
perforated mirror, the focusing lens, and the variable angle lens.
※
When using a vision corrective lens or a FA barrier filter, the fundus image passes
through such a lens or filter before it reaches to the focusing lens.
④
Variable angle lens
⇒
Finder or CCD Camera
＜
Non-mydriatic photography
＞
Fundus image directed through the variable angle lens is reflected by a mirror and
captured by a CCD camera for non-mydriatic. Captured fundus image is displayed on
the LCD monitor.
＜
Mydriatic photography
＞
Fundus image directed through the variable angle lens is reflected by the mirror towards
the finder that allows you to observe the image.
＜
FA
＞
Fundus image directed through the variable angle lens is reflected by the mirror towards
the finder that allows you to observe the image. However, when using a barrier filter,
you may observe the part of fundus image that is excited by the filtered illumination
light.
⑤
Photographic Modes and Cameras
＜
Mydriatic/Non-mydriatic/FA
＞
- Selecting “35-mm film” -
When pushing the shatter switch illuminates the flashlight, the lower return mirror
pops up and a 35-mm film captures the image. At the same time, the image is
captured into the data card.
- Selecting “Electronic Image” -
When pushing the shatter switch illuminates the flashlight, the upper return mirror
moves aside and a camera connected to the video adapter captures the image.