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Wide-Gamut monitor with 5050 RGB LED mod.

Increase the Color Gamut, Primary color purity and make stunning vivid and accurate LCD monitor with RGB LEDs. Inspired from Dolby PRM-4220.

thomas-chanon-wangtriratThomas Chanon Wangtrirat
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Hi! I'm Thomas. I'm cinematographer and mostly I will do color by myself and sometime have to have trusted monitor that shows true color from the camera.
I have Dell 2408WFP which used WCG-CCFL (Wide color gamut CCFL). This kind of lamp tend to aged with warmer color and massive green tint. Even though it's better than normal sRGB display. It can't show you the TRUE color of the scene, kind of blueish or greenish bias to white color.
More confident on Color grading that will master the look as your decision.
For most users? This mod will blown your mind of how vibrant this mod will change your monitor.

Inspired from Dolby PRM-4220 reference monitor which used 1536 OSRAM Ceramos MultiLEDs to light up stunning 42" LCD grade 1 display.

This method has been used in Flagship LED LCD TV like XBR-8 from Sony.

This mod will not going to make your monitor brighter because poor co-efficient of RGB LED.
But make your monitor to show more saturated color.

How Wider gamut make more beautiful picture?

The Sony TRIMASTER BVM-L Series employed RGB LED Backlight for there master grade 1 reference monitor. Lower one PVM all used WCG-CCFL. That's how extraordinary the RGB LED Backlight!!!

I took of the BLU (Backlight Unit) from LCD Panel in this case is Samsung LTM240CS S-PVA which exhibit really deep black point due to it's contrast ratio.

It have 7 u-type CCFLs. Removed it and take care in case you want to go back.

I placed several 5050 RGB LED Strips and connecting it in parallel. Distributed the power from several point of total LEDs to not put too much power load on copper conductor on PCB. Connect to Mosfet to drive it with PWM control on Arduino RGB code. Set white point with DSLR camera or Calibrator via adjusting on arduino. Power requirement is nearly 100w but trade-off to have pure color.

Here's how it achieve my goal.

I calibrated the RGB portion to match 6500K white point with my i1 colorimeter which have tool to test the white point.

Adjust the RGB portion from arduino with your own technique.

Drive it at more than 5000Hz because if too slow it will cause eye-strain.

Now, monitor can achieve stunning >120% of Color gamut from 110% of Dell 2408WFP. White is so pure that I can spot different in bias of white in the scene. Skintone and other tonality is more accurately represents.

Disadvantage :

- You have to calibrate after assembled the monitor and wait for at least 30 mins to stabilised the color of RGB LED especially Red LED which prone to shift when temperature get higher. Most RGB LED and GB-r backlight at present feature Color sensor which sense the primary color of backlight and adjusted on the fly to correct color temperature of backlight unit. If you have arduino code and method to achieve that please posting it to me.

- Panel gets warm on operation. Need some fan to blow it.

- Uniformity of panel is not good because of optic of LED it self. it required more deep BLU to diffused multi LED array to lit up panel Or Try to put more dense array configuration.

Here is sample which graded on DaVinci Resolve with this monitor. Warm tone on graded is my look I attend to it .

  • 10 × 5050 RGB LED Strip 60LEDs / m
  • 1 × Arduino Just any arduino that can output pwm signal 3 channels
  • 1 × PSU to power 12v with power of 100w 8A 12v will be fine.
  • 3 × Power Mosfet to drive 3 LED channel of R G B LED. pick one you like.

  • The LED chips keep randomly crash

    Thomas Chanon Wangtrirat • 02/16/2017 at 01:04 • 0 comments

    It keep failed at chip so another one in chain get ruined until you change out LED to fix it.

    Maybe cause from thermal different when it's in operation and when completely off.

    I don't have any solution right now to solve it. So I kept it lower brightness but always on to not make it fail.

  • Switch to WS2812b RGB Digital Addressed LED

    Thomas Chanon Wangtrirat • 01/09/2017 at 20:24 • 0 comments

    At Last log I made was the 5050RGB LED which post serious problems on Temperature from reduction of voltage by using passive circuit in means of used of resistors.

    I have made new one accommodate with HP LP2475W which is Backlit CCFL IPS Display.

    BTW, Bulb life go as long as 7700hrs which tend to give yellowish white and less color purity.

    RGB LED known to be the best of color display known to me. So I bought WS2812b RGB LED Strip for 20M.

    This is how it get working perfectly, Color different was gone!!!!

    BUT Heat issue still remain. 5V need very very huge current to drive. nearly ~1000 LEDs lit all RGB at portion. Controlled with Arduino Micro.

    I cooled it with some Notebook CPU Fan. Fits in display's enclosure snuggled.

  • Maintenance the LEDs.

    Thomas Chanon Wangtrirat • 05/01/2016 at 03:35 • 0 comments

    Sometime huge array of LED that has been assembled by hand, sure that it will have fault by heat or loose connections sometime. So I maintaining it after being use as Mastering monitor for 5 months.

  • Comparing WCG-CCFL vs RGB-LED

    Thomas Chanon Wangtrirat • 11/24/2015 at 05:41 • 0 comments

    Left : Dell Ultrasharp 2408WFP with WCG-CCFL Backlight


    Right : Dell Ultrasharp 2408WFP with RGB-LED Backlight


  • Uniformity problem mostly solved

    Thomas Chanon Wangtrirat • 11/21/2015 at 03:03 • 0 comments

    I purchased 7 rolls of RGB 5050 24v 5m per roll.

    Seller managed to send me same batch but the problem remained. It's mixed new and old LED chip in line of ribbon. So I have to cut and connect with same batch. About 10% of all 4 rolls that I used have different colour.

    After manage it to almost same batch. The colour uniformity is absolutely amazing as in the picture.

  • Another one get assembled

    Thomas Chanon Wangtrirat • 11/19/2015 at 23:20 • 0 comments

    Last time I got badly differrent batch of LEDs. And so I alternated between 4 rolls of them.

  • Color Uniformity Correction

    Thomas Chanon Wangtrirat • 11/02/2015 at 12:08 • 0 comments

    After assembled the backlight unit. I stuck with the color problems. Because this monitor used so much of 5050 strip. I used all 4 rolls of 5m RGB LEDs 5050 and found that last roll has differ color compare to Roll 1-3 which led me to do some passive corrections.

    I found that problematic roll have sightly lower in blue output so I bypass the resistor of blue channel in every strip on 4th roll and bypass green and blue channel on Roll 1-3. So the color will be nearly match. This is not perfect solution but it help me do better than nothing. Absolutely time consuming and frustration.

    In the photo you may see some banding because I just test drive it with cheap RGB IR remote. PWM driven.

    Real assembly will be use with Arduino drive at 5000Hz+ to produce Flicker-Free BLU.

    It may seem to have no problem at all with color after corrections, If I bring down exposure it should be easier for you to spot. But I just shot this exposure right away to get rid of PWM banding. Easy for your eyes folk!

    I suggest to double check the batch of these kind of LED before begin to assemble the strip on BLU panel.

    For who don't to be hassle with this kind of problem. I think WS2812b Digital LED which drive at pixel level of each LED will do much better job but with more budget to spend on strip. 5050 WS2812b RGB with 144LEDs per meter will do great job on brightness level and uniformity, But It's to much to be something to dream of, that cost much as buying a good sRGB monitor. Nevertheless, in the future I may doing it. It will be fantastic to imagine with each pixel being control individually. Yes, Local dimming RGB backlit display. That's my wish for next project.

    Absolutely hard to QC this backlight. This shows me completely of why the RGB-LED backlit monitor is so expensive.

  • Light up! 1026 RGB LEDs BLU

    Thomas Chanon Wangtrirat • 11/01/2015 at 23:59 • 0 comments

  • RGB 5050 24v strips arrived.

    Thomas Chanon Wangtrirat • 10/31/2015 at 06:15 • 0 comments

    I have assembled another 2408WFP backlight unit with 10m+ of 5050 RGB LEDs. Very dense array.

    Total LEDs : 1026 LED

    Used checkerboard pattern and vertical layout to spread the light from LED chip even more to improve Uniformity.

    24v will use less current than 12v. So, less energy wasted in copper conductor underneath pcb.

    Stay tunes.

  • Bought some more 5050 RGB strip.

    Thomas Chanon Wangtrirat • 10/20/2015 at 23:59 • 0 comments

    Try to make denser array to fix uniformity problem.

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Theo wrote 11/21/2015 at 16:10 • point

Nice project, I think I might give this a go on my panel as the warm LEDs I am using are pretty awful. Perhaps you could mount a color sensor such as the TCS34725 in the center of your LEDs and measure the color reflected back off the diffuser. 

  Are you sure? yes | no

Thomas Chanon Wangtrirat wrote 11/22/2015 at 05:02 • point

I have looked at several OSRAM white paper about colour control. They have proprietary chip to do it but I don't get hand-on yet.

LED are really really hard to qualify on this kind of off-shelved product. I have to purchased 7 rolls to make 4 rolls usable batch and have to tell seller to get same batch before sending. 

Maybe WS2812b Digital LED 60 LEDs/m will do the same job as this and do better!

I kind of looking for edge-lit mod right now. It's more consistent and cheaper to do.

  Are you sure? yes | no

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