We removed the light engine module of the DLP4500EVM and exposed the DMD to the optical platform. The collimated beam generated by the 808nm laser is irradiated perpendicular to the DMD plane, resulting in a reflection projection at an angle of 24 degrees according to the manual. But we have observed that in addition to a desired projection, there is also the generation of diffraction images, as shown in the figure. What is the reason for this, please? How should it be eliminated?