DLP3010EVM-LC: Product Recommendation for Fast Field Sequential Display of Static Images

Nick,

Welcome to the E2E forums, and thanks for your interest in our DLP technology.

The HDMI interface adapter has a 150MHz pixel clock limit, limiting the framerate that can be input from external sources. What you are asking to do may not be possible if you intend to feed the images through an HDMI source.

For high framerate pattern display, we recommend using the internal pattern streaming modes. What sort of application are you looking to use the EVM for?

Regards,
Philippe Dollo

Hi Philippe,
Thanks for the reply.
Tell me more about the internal pattern streaming mode. If I can store the images internally, that would be fine. I don't need to use HDMI. Can the EVM handle cycling through color images in rapid succession at 360Hz (I'm hoping to get 6 images at 60 Hz each)? I'm sending the light to some optics that will sync with the EVM using the trigger features.

I'm certainly open to other products if you think something would work better.

Thanks!

Hi Nick,

If you haven't seen it already this FAQ on the light control platform may be helpful. Internal patterns mode can only be used for 1D patterns (see FAQ definition for this). Are you looking to use 1D patterns? If not you will have to use external streaming.

Also, can you describe your desired images? Are they 1-bit depth or 8-bit depth? Could you give an example of the projection order and desireable characteristics? My understanding is you want the following:

Image Number	Image 1	Image 2	Image 3	Image 4	Image 5	Image 6
Illumination	RGB	RGB	RGB	RGB	RGB	RGB
Exposure Period	1/60s	1/60s	1/60s	1/60s	1/60s	1/60s
Bit Depth	8-bits?	8-bits?	8-bits?	8-bits?	8-bits?	8-bits?

Please let us know.

Thanks,

Kyle

Hi Kyle,
You have everything correct except the exposure period. The exposure period for each image should be 1/360s. The total period for the full cycle of images should be 1/60s. If that's asking too much, I can probably get by with only 4 images for now, which would reduce the frame rate to 240Hz.

Thanks for the help!

Nick

I'm still looking for a product recommendation. If anything you have will work with my application, please let me know.

Thanks!

Nick

Hello Nick,

I'm sorry for the delay. Unfortunately you will not be able to achieve an exposure period of 1/360 = 2,778us for an 8-bit image with RGB illuminators. I would also like to clarify that RGB means the entire image will be illuminated with a red LED, followed by green, then blue. In other words, your resulting image will be all white. Is this okay?

If so, the fastest exposure periods you will be able to obtain are as follows:

• 8-bit, 1 illuminator, internal: 1,677us (also requires 171us pre-exposure dark time plus 31us post-exposure dark time for effective frame rate of ~532Hz)
• 8-bit, 1 illuminator, external: 2,555us (also requires 171us pre-exposure dark time plus 31us post-exposure dark time for effective frame rate of ~363Hz)
• 8-bit, 3 illuminators (RGB), internal and external: 10,912us (also requires 171us pre-exposure dark time plus 31us post-exposure dark time for effective frame rate of ~90Hz)

If you only need 1-bit images you will be able to achieve a much faster rate. Please let me know if any of those options work for you? 

Thanks,

Kyle

Hi Kyle,

Now I'm more confused. I apologize. I think I misunderstood your nomenclature. Let's start over.

I want to display 2D color images in fast sequence. For example, image #1 might be a photo of an apple, image #2 might be a photo of a banana... I need each image to display 60 times per second. If there are only two images in the sequence, then each image would alternate on the screen. The total period would be 16,667us and in this period both images would need to be displayed. Each image would have a period of 8,333us. If we add more images, the total period of 16,667us stays the same but the individual period for each image would decrease because we're displaying more images during the same 16,667us.

I understand that each image would be made of 3 sub-images in sequence, each illuminated with the colors RGB. I assumed that 8-bit was how you achieved gray scale with these illuminators. Please correct me if I'm wrong. A totally white image is not useful. I thought I could achieve faster rates by loading the images into the controller rather than streaming them through the HDMI. Again, correct me if I'm wrong.

Based on your responses, it doesn't sound like this product can even display 2 images at that rate if 90Hz is the fastest it can go. When the datasheet claims that it can accept 120Hz framerates, what does that mean? Do you have any other products that you can recommend?

Thanks!

Nick

Hello Nick,

Sorry for the confusion. Do your color images need to be 24-bit (i.e. 8-bits each for red, green, and blue)? If so your requested framerate would be 360Hz. Unfortunately this is not something we support on the DLPC3478. Additionally, the DLPC3478 cannot rapidly switch between colors on a per-image basis.

You may be interested in the DLPLCR4500EVM which can create custom bitplanes (i.e. rapidly switch between colors on a per image basis). However, you are limited to 120Hz 8-bit patterns.The DLPLCR6500EVM can achieve similar functionality at 360Hz.

However, I would like to better understand your application for this fast rate of projection. In general, these fast rates are for applications such as structured light. In these cases 8-bit patterns and monochromatic illumination are usually used. If your application is different perhaps I can better direct you to the proper product or resources. Is this for a display application or some other usecase?

Thanks,
Kyle

Hi Kyle,

This is for a display application. I'm using it to test some downstream optics that will sync with the DMD and separate the images. Originally, I hoped to get 6 images in the sequence with 24-bit color. It sounds like this might be asking too much. So, now I want to know what the options are. If I keep the 24-bit color, how many images in the sequence can I get? If I reduce to one illuminator (e.g., white light?) at 8-bits, how many images can I get? (I assume the options are 1-bit or 8-bit for each illuminator? There isn't something in between?)

You mentioned 360Hz for the 6500 above. I assume this is for a single illuminator? If we go to RGB, then the effective frame rate would be 120Hz?

You can probably tell that I know very little about DMDs. Do you guys have a phone number? It would be way faster than communicating via the forums.

Thanks!

Nick