DLP7000UV: Prism, light angle to DMD

Hello Taka,

Q1)
Why use this prism?
Is it to efficiently input and output light to the DMD?

This is to make the design more compact, otherwise the illumination source mast be placed much further from the DMD and the projection lens further away to allow the illumination bundle to be unobstructed.

Q2)
Will using this prism be a way to suppress DMD diffracted light?

Unfortunately the answer is no.  Diffraction is a fundamental interaction between the coherency of the laser and the periodic spacing of the micro-mirrors.

Q3)
Is ±12deg a necessary condition for the light diffusion angle incident on the DMD?

This is because the nominal tilt is around 12 degrees.  The tilt can be anywhere between 11 - 13 degrees even in one device.  That is why illumination is typically centered around 2*12 degrees = 24 degrees from the DMD normal.

Or should it be less than that?  See above.

If the light source is a laser, is it okay to use less than ±1°deg?  

Yes.  Since you will have discreet orders you may end up moving the illumination a little to center the order of interest on the normal of the DMD. 

If your are going to work in collimated space after the DMD then you may have a challenge with the energy distribution in the orders nearby.

If you are re-imaging the surface of the DMD on a production surface, if possible collect the nearest 4 to 5 orders.  They should reconverge to a correct image.

Fizxi

I understand the role of prism.
I felt that I needed to understand the optical system of DMD.
Please continue to ask about these questions in the other question "DLP7000UV: Diffraction light."

Thank you very much.