Photodiode PR5020/21

Application Notes

CHANNEL SEPARATION

The crossover of a light beam between photo-

diodes is illustrated. Increments of 10 µm were

performed using red light and a diameter of

50 µm. The position of 0 µm corresponds to the

center of the die. The photocurrent was mea-

sured with zero applied voltage.

Considering a gap between the photodiodes of

27 µm, the observed behaviour is consistent

with a sharp channel separation.

POSITION DETECTION

By shining light on aperture, the passing light

can be detected. As given in the schematics

above, three different segments can be

resolved using PR5020/21. Due to the geometry

of the photodiodes, the position of the aperture

can be detected as given in the diagram.

Of course, the principle can be transferred to

encoder discs to obtain angular resolution:

© PREMA Semiconductor GmbH 2018 I rev. 5119

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