DLP4710EVM-LC: The areas in the projection that are supposed to be black are too bright.

Hello,

Welcome to TI E2E forums and thanks for showing interest in the DLP Technology.

Can you please confirm that you are displaying the patterns using external pattern mode only? If yes, kindly share the screenshot of your pattern configuration details.

Regards,

Mayank

Hello,

as far as I can tell, I am not using any patterns. To display the image I set the projector as a second monitor and make the image full screen there, if that information helps. I am attaching screenshots of the tabs under light control. Hope that helps.

Hello,

Do you have similar issues with contrast when using an internal pattern (a black/whie checkerboard test pattern for example)?

Kindly,

Austin

Hello,

the same issue persists with the internal patterns as well. I could not photograph the checkerboard well with my camera, but I have attached the image when I choose "solid color, black" pattern.

Regards,

Ege

Hello Ege,

Kindly let us know the firmware that you are currently using. We will try to reproduce the issue at our end.

Regards,

Mayank

Hello,

You can find the photo of the information page below. Sorry about the delayed response, I didn't have access to the device for a while.

Regards,

Ege

Hello Ege,

Thank you for the information above. We are investigating this issue.

Would you be able to measure the light output of the solid, black pattern with an oscilloscope and photo-detector? We would be interested in seeing these plots if possible.

Kindly,

Austin

Ege, 

In addition to what Austin mentioned, I would encourage you to move over to the latest firmware version (v8.1.0) that is available on ti.com and check you are still the same behavior or not.

Regards,

Mayank

Hello,

I don't have the necessary equipment but I will ask around to see if the other labs do. I will keep you updated.

Regards,

Ege

Ege,

Yes, before that kindly switch over to the latest firmware version and check out the behavior.

Regards,

Mayank

Hello,

I have updated the firmware to the latest version, the same behavior persists.

Regards,

Ege

Hello, 

Unfortunately I cannot provide these plots as we do not have the equipment.

I have updated the firmware as well and the behavior persists.

Regards,

Ege

Ege,

Did you change any default settings in the firmware. Were you seeing such behavior from the start itself, or is it something that was seen after making certain changes?

Also, can you display a solid black Test Pattern using the Test Pattern Generator mode and let us know if the behavior still persists or not.

Regards,

Mayank 

Hello,

I haven't made any changes to the firmware. It was like this from the start, I have only just realized the severity, trying to photograph the propagation of the light inside the resin.

The behavior persists with the solid black test pattern as well.

Regards,

Ege

Hello Ege,

Thank  you for your patience. It is holiday time holiday time for some of our team members. We will get back middle of next week on this subject.

regards,

Vivek

Ege,

Per Mayank's comments above, you should try to project a solid black test pattern (with LEDs enabled) to determine whether the issue you are seeing is due to optical light leakage or a problem with the dynamic range of your video feed. 

Using the Solid black test pattern will let you isolate the LED output from your video source. Meanwhile, you should try alternative video sources to see if you are outputting full dynamic range.

In addition to this, I also recommend that you ensure CCA (Color Coordinate Adjustment) is disabled (command 0x86W, 0x87R)) and disable it if it is.

I hope this helps.
Regards,

Philippe Dollo

Hello Philippe,

I have the same issue with the solid test pattern, the surface is still lit up.

I have made sure that CCA was disabled as well.

What will I be looking at to test whether I am outputting full dynamic range?

Thank you.

Regards,

Ege

Hello,

I unfortunately do not have a means of measuring the light output.

Regards,

Ege