Ricoh PJ LW3000ST, Field Service Manual

Page: 127 / 130

It is divided into 4 segments comprised of green, blue (diffuser), red, and yellow (transparent).
Laser bank
Each laser bank is comprised of 24 laser diodes (4, 5, 5, 5 and 4) and is cooled by the heat pipe.
Projection Light
Blue laser light turns into a diffused light in its optical path and then its coherence is lowered as it passes
through the filter wheel and other parts, so the projection light is not dangerous.
* What’s coherence?
Coherence refers to the characteristic of waves, indicating the degree of interference (clarity of the
interference fringes). Natural light and lamp light have diverse light wavelength and direction of
radiation. Thus, they have low coherence.
On the other hand, laser has the same light wave length and direction of radiation. Thus, it has high
coherence.
Laser
125