1.) did u make any modificatoins to the light?
2.) are you sending it a signal from the computer when u are testing it? are u seeing ur desktop?  Sometimes the light wont turn on unless a proper signal is being sent to the monitor

nima - 04 May 2008 02:16 AM

1.) did u make any modificatoins to the light?
2.) are you sending it a signal from the computer when u are testing it? are u seeing ur desktop?  Sometimes the light wont turn on unless a proper signal is being sent to the monitor

i think the backlight is toast, its only lighting on 1 bulb per side, im going to replace it with LEDs or try another backlight I have well see how it goes.

How did you break the bulb?

You should be careful when disposing of the CCFL (any CCFL lightbulbs for that matter).  They need to be recycled because they contain minute volume of mercury vapor that shouldnt leak into the eco-system.

If the bulb actually broke (glass shattered) and the white powder spilled out, you should sweep it up with a brush and dustpan (no vacuum) and put the contents inside a ziplock bag, and then recycle it.

nima - 05 May 2008 02:11 PM

How did you break the bulb?

You should be careful when disposing of the CCFL (any CCFL lightbulbs for that matter).  They need to be recycled because they contain minute volume of mercury vapor that shouldnt leak into the eco-system.

If the bulb actually broke (glass shattered) and the white powder spilled out, you should sweep it up with a brush and dustpan (no vacuum) and put the contents inside a ziplock bag, and then recycle it.

Its only lighting from the right side, no shattering or anything it just isnt working properly heh. I ordered some LEDs to replace so ill be waitin on those.

Dear friends.
LED array back-light will emit a lot of heat , will it significiently reduce the life of Lens and light sensor? have you considered this heat issue?
besides, I want to know if someone think of replace the common used full-color based CMOS sensor to a mono-color sensor, like National Semiconductor LM9617.

Besides, Nima , you said you bought some film cover the CCFL to block IR emit , Could you tell me where can I find those films ? or give me some pics about the cover please?

What issue will heat incur, exactly?

I think his plan is to make two rails of white-LED’s and shine them inside the acrylic light block.  The metal bezel of the LCD can serve as a heatsink, and an additional layer on top will be fine.  The CCFL produce heat as well. 

As for camera’s, I am not using a CMOS chipset based camera.  I’m using a unibrain fire-i with b+w monochrome 1/3” CCD imaging sensor.  But I do agree that a B+W image sensor will provide sharper blobs because they are using a different subpixel matrix.  I wouldnt know which camera would use that specific chipset exactly.

jiang - 05 May 2008 11:45 PM

Dear friends.
LED array back-light will emit a lot of heat , will it significiently reduce the life of Lens and light sensor? have you considered this heat issue?
besides, I want to know if someone think of replace the common used full-color based CMOS sensor to a mono-color sensor, like National Semiconductor LM9617.[/quote

Unless, of course, you are referring to LCD monitors that are bigger than 21” which use a light-grill directly behind the panel.  Then you will need a lot more LED’s to illuminate the screen and the LED’s will make more heat.

jiang - 06 May 2008 12:19 AM

Besides, Nima , you said you bought some film cover the CCFL to block IR emit , Could you tell me where can I find those films ? or give me some pics about the cover please?

From any hardware or home supply store (Home Depot).  It is the standard film ppl here use to block IR.  It’s made to line windows to help with heat management

Thanks Nima， What I want to build a PCB and surface mount the light sensor with the LED-grills, my setup is about 37 inches, and My hardware friend told me the LED-Matrix emit considerable light. and I am also thinking of how to solve the lens problem (short focus and wide angle)…

jiang - 05 May 2008 11:45 PM

Dear friends.
LED array back-light will emit a lot of heat , will it significiently reduce the life of Lens and light sensor? have you considered this heat issue?
besides, I want to know if someone think of replace the common used full-color based CMOS sensor to a mono-color sensor, like National Semiconductor LM9617.

The CFL backlight got extremely hot to the touch, I cant imagine it was that much cooler than the leds will be. I have fans inside the box to vent, I dont anticipate any problems with heat…

jiang - 06 May 2008 12:30 AM

Thanks Nima， What I want to build a PCB and surface mount the light sensor with the LED-grills, my setup is about 37 inches, and My hardware friend told me the LED-Matrix emit considerable light. and I am also thinking of how to solve the lens problem (short focus and wide angle)…

LED’s are more expensive than CCFL but will do the job.

As for wide-angle lense, how high is your table?

Mine is 23 inches (same height as MS Surface and I have a 37” screen.  I’m using a wide-angle lense f2.1mm, 71 degree)

What LED matrix are you going to use?

I was thinking of buying a strip of high-power white LED’s to compensate for some light loss as a result of the CCFL being displaced.

But I got finger tracking going on the 37” so I’m at the stage that I want to improve certain aspects of the design.

i bought a set of rails off ebay using high power white leds from hong kong, waiting for them to arrive...hoping they are brighter because i too had lost light from the CCFLs some escaping downward into the box. What model 37” lcd are you using? any issues taking it apart?

I’m using a 37” LCD HDTV I bought from CostCo.  It’s an OEM using LG.Phillips chipset and other OEM components.

There is a big difference between LCD’s that are for computers and televisions.  Basically, once you go over around 21”, they using a different backlighting system.

15-19” LCD monitors use reflected light from a light-guide as the backlight, while big screens use rails of CCFL (around 11-12) direcly behind the screen.

Tear-down of 37” was, of course, much more difficult than the 19” I took apart.