Huvitz HLM-1, Service Manual

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8
AUTO
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LE
NSMETE
R
 Signal Receiving Part
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Hartmann plate : divide the signal into 81 points. Prevent the other light except the
signal
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2-dimentional CMOS sensor : converts signals into digital value.
1.6.
Measurement Principle
Basic Principle
When there is no lens (0D state), parallel light that has transmitted the collimator lens
passes the pinhole and makes image on CCD. In case of convex lens (lens with plus
diopter), parallel light that has transmitted the collimator lens converges through the
measuring lens, passes the pinhole and then makes image on CCD. On the other hand, in
case of concave lens (lens with minus diopter), parallel light that has transmitted the
collimator lens diverges through the measuring lens and then passes the pinholes and at
last makes image on CCD.
2.
Initial State
Concave Lens
Convex Lens