DLP660TE contrast error

Hello Shurong Zhang,

The contrast of your image is going to be directly dependent on your optical system as well as video input. I have to check with some experts about what the expected settings are for the different power modes as well as projection modes.

If you are trying to look at an image you are displaying from an external source the projection mode should be set to 'external.' Again, I need details on what the other modes are doing, typically I test without an optical engine while in the lab.

Your second question will also need to be addressed as well. Thank you for your patience!

Best,

Aaron

Our basic locking contrast issue is related to the firmware configuration of the DLP4422,

We use the same optical lens and two TI's 4422 EVM circuit boards. The hardware of these two circuit boards is the same, but the firmware programs are different. There is a projection effect for Picture 3 (using the firmware officially provided by TI), and the other one can project the effect of Picture 2. We suspect that another piece has modified some configurations of DLPC4422 by using Ti's composer, and we also want to achieve the same effect.

We want to use it in 3D printing. We use the light source of LD, and only the contrast effect of Picture 2 can meet our needs. We suspect that the internal image processing algorithm in DLPC4422 has resulted in an increase in brightness and a decrease in contrast of black images.The project is currently very urgent, and I hope TI can provide support.

Hello Shurong Zhang,

I understand you are working with an engineer already and we have a conversation through e-mail. If you would like, we can discuss your setup in detail through this e-mail instead of on a public forum.

Could you check that you are connecting to illumination control on both boards through identical J39, J34, J14 and J3 jumper settings?

Please advise what is different about the firmware programs and what is meant by:

shurong zhang78 said:

We use the light source of LD

Best,

Aaron

Hi， Aaron,

We did not have any mail communication with the engineers in the United States, we only had email communication with TI FAE in China. The FAE responsible for TI China stated that the 660TE only supports visible light bands and he cannot support applications that are not in the visible light band. But we are using it in the field of 3D printing. Our wavelength is 405nm LD, only blue light, and the light source is processed by ourselves. For our 3D printing project, we need technical assistance from TI's original factory. May I have your email? I hope you can also participate in the discussion through email.

We did not use J39, J34, or J14 to control the light source. The light source control is driven by our own software, and we keep the LD emitting light at a certain power. During the operation of 4422 EVM, the LD will not be adjusted. Additionally, the two EVM boards you mentioned have identical light source controls.

We suspect that the firmware difference of 4422 results in different light output effects for all black images. For two EVM circuit boards, we set the LD to always emit the same power and project a black image in blank curtain mode. The effect is different. The brightness of a black image projected by one firmware is strong, while the brightness of a black image projected by another firmware is weak.

blankcurtain mode   black image (firmware 1)

blankcurtain mode  black image  (firmware 2) 

I think if I cast a black image on Blankcurtain, shouldn't DMD micromirror remain in the off state? Why do different firmware have different projection effects on black images? We measured the test point of 660TE with an oscilloscope, MBRST0->MBRST15, and did not detect any changes in the level. What is the internal timing of DLPC4422 controlling DLP660 when casting black images?

In addition, the above tests all use the same lens. The above test lens is fixed, and we can exclude the lens factor.