DMD Chip

Wayne,

A belated Welcome to the DLP section of the TI E2E Community.

I am very sorry that your question appears to have gotten overlooked until now.

Please look at the attached document.  It should answer quite a few of your questions.  If you still have questions after reading it please post back.

Dear Sir,

thanks for your reply. I have a question about 0.55''.

I think it means 0.55 inch in diagonal line. And it is a 4:3 rectangle.

So that makes the size of the dmd, length= 0.55 * 25.4(mm)*(4/5)=11.176 mm       height= 0.55 * 25.4(mm)*(3/5)=8.382 mm

Also I know the gap between the pixels is 1 um, and the pitch between the pixels is 10.8 um

But what's the length of one pixel??  And are these pixels square?

thanks

Wayne,

If you are refering to the 0.55" XGA (1024x768) DMD, here are the dimensions. The DMD is 0.55 inches across diagonally. The mirrors are 10.8um in width and they are squared. The width of the active mirror array is 11.059mm and the height of active mirror array is 8.294mm.

Hello Wayne,

WYA is correct the mirrors are square.  The pixel pitch is 10.8 um and the gap is approximately 1 um.  This makes the actual mirrors approximately 10.8 um minus ~1 um.

I hope that helps.

Fizix. 

Thanks for your help.

But I still have a question. When DMD is not activated, are these micro mirror set flat (not tilt +/- 12 degree)??? If this is the case, it should be  convenient to measure the pixel size and the gap. 

Besides, as you mentioned, the gap is approximately 1 um. How is  this size measured (measured when set flat or tilt)?? 

Hello Wayne. 

The gap references when the mirrors are nominally flat. 

When the mirrors are powered they are actually landed to the surface at + or - 12 degrees.  When no power is applied the mirrors return to their rest position which is approximately flat.  However the flat state cannot be "set".  When the device is powered there are only two states available + and - 12 degrees.

Fizix

Hi, Fizix

One thing that I wanna make sure is that what is the width of one pixel of the DMD?

Is it 10.8 um or 9.8 um (10.8-1)? Because these two is very differnt.

WYA replied by "The mirrors are 10.8um in width. The width of the active mirror array is 11.059mm"

But you replied by "pixel pitch is 10.8"

thanks

Wayne,

The "pixel pitch" refers to the distance from the center of one mirror to the center of an adjacent mirror.  This value is 10.8 um. 

The size of the individual mirror is approximately 9.8 microns on each edge.  The gap size can have some variation.   This is why I said the gap is approximately 1 um. 

I hope this information helps.

hello  Fizix

I    have   a  question,  is   the    0.7''XGA    DMD    the   same   as    0.55''?   The "pixel pitch" refers to the distance from the center of one mirror to the center of an adjacent mirror,   so  the  "pixel pitch"  is   13.68   um?     Or    it    is   14um?     Because  in   my   experiment   "14um"  is  appropriate.

THANKS

Hello Xiaofeng,

Welcome to the DLP section of the TI E2E community.

These device have the same number of pixels (XGA - 1024 x 768) but the "pixel pitch" is not the same.  The 0.7" XGA DMD is a 13.68 um pixel pitch device and the 0.55" XGA DMD is a 10.8 um pixel pitch device.

I hope this helps.

Fizix

Dear Sir

thank you for your reply for my question,it helps.

i have another question now.Recently,i am on my experience of DMD diffraction pattern.But to my surprise,for the same model 10.8um,12° switch angle DMD,it has two different diffraction patterns,one ,the energy concentrate on the middle point, which means there is only one point very bright . the other, the energe is distributed by the middle two points,which means there are two points very bright.  I can not  find  the  reasons,is there any other  parameters decide the diffraction pattern besides 'pixel pitch' and 'switch angle'?

ps:i use 405nm wavelength laser

thank you

Hello Xiaofeng,

Would it be possible to attach an image of what you are seeing.  It sounds like you may be seeing reflections from the window of the intial incident beam, but I would like to see an image of it to better understand.

Fizix.

hello sir

as you see,for the same conditions the diffraction pattern is different,why?   

ps:the same conditions includes:incident wavelength(405nm),incident angle(24°),pixel pitch(10.8um),switch angle(12°)

Hello Xiaofeng,

First, excellent pictures!  That is exactly what I was wanting to see

Now let me ask a couple of questions:

1. Where are these two patterns located relative to the normal of the DMD surface?
2. What pattern is being displayed on the DMD for each of these patterns?

Hello Fizix,

first, let me answer your two questions:

1.    the two patterns are parallel to the DMD surface.

2.    all the mirrors of DMD are on the "ON" state.

then let me show you my experiment schematic diagram:

Hello Xiaofeng,

Could you tell me the separation (in angle) between the center of the one pattern and the center of the other pattern?

Also would it be possible to get a picture that shows both patterns in one picture, so that I can see their spatial relationship to each other?

Last, how much of the DMD surface are you illuminating? 

Thank you,

Fizix

hello Fizix

the two patterns are independent, they are made by two experiences.(the same experience system, only the DMD changed)

The DMD illuminating surface is  the same as laser beam surface.

thank you

Hello,

Please, I need the dimentions (height and width)of the DMD used on all the Digital Projector 2K and 4K, where can I get it?

Best Regards

Hello Jesus,

Information shared in this forum is primarily for TI DMD chip sets listed on www.ti.com/mems and is typically for applications other than standard projectors.  The mechanical specifications are provided in the data sheet for each DMD listed on www.ti.com/mems.  Perhaps that will provide you some useful information.

http://www.ti.com/product/dlp5500

http://www.ti.com/product/dlp3000

http://www.ti.com/product/dlp9500

http://www.ti.com/product/dlp7000

Why do you need the height and width of DMDs used in all 2K and 4K digital projectors?

Thanks,

Eric

Hello Eric,

I need the height and width to calculate the correct lens to order.

Best Regards

Jesus Ruibal

Hello Jesus,

I understand.  It does not look like the information I provided will be of much use and the DMD information you requested is not publicly available.  Perhaps the respective projector manufacturer can provide you information regarding the lens itself?

Best Regards,

Eric