YouTuber Matthew Perks, AKA DIY Perks, showcased his DIY dual-layer LCD monitor earlier this week. It is a homespun answer to the problem of LCD dimming and an attempt to gain increased contrast through deeper blacks on an LCD display. It utilizes a pair of LCD panels from off-the-shelf monitors.
There are a few current popular computer monitor technologies available today. Firstly there are LCD monitors which employ a full white backlight covering the full screen. In this type of monitor colors and black are generated by liquid crystals letting the backlight through unaffected (white) coloring or attempting to block the light (black). LCD IPS monitors usually have a definite dark grey appearance at their darkest points, while LCD VA monitors are a bit better in this regard. Also, LCDs can sometimes suffer from backlight bleed due to the full and intense white light behind the pixels. More modern LCDs may employ dimming zones where the backlight can be turned off for better contrast, with more zones working with the monitor firmware for more refined local dimming. There are also screens with much more granular backlighting tech called mini LED and micro LED displays. We don’t need to get into those here, but will also mention OLED, where each screen pixel is its own light source – so there is no backlight required.
The first idea DIY Perks tried, in the quest for a more OLED-like display on a budget, was to get two identical monitors and place one panel in front of the other to have a black-deepening effect. One monitor was left intact and the other stripped down to its very thin and delicate display panel (with no backlight).
Unfortunately, the first attempt showed that the two-panel darkening effect was so strong that no image was visible at all! Undeterred, DIY Perks analyzed the issue and found it was due to superimposed polarization layer There are depolarization films available, but they are prohibitively expensive, said the intrepid YouTuber. As a make-do solution, he found placing tracing paper between the panels did very much the same job. With this hurdle behind him, the resulting image quality was judged to be dim all over, not just in the black areas.
To tackle the dimness problem, the obvious next step was to give the monitor backlighting a boost. The source monitors only used backlighting from the edges, so Perks decided to create a much more intense backlight by filling the whole background with a matrix of LEDs. To avoid visible light peaks and troughs, tracing paper was used again, but for the best diffuse effect it had to be a little distance above the lighting array.
To get the new system to work, the remaining monitor needed to have its LCD extracted and placed on top of the other display (separated by tracing paper). With this done, the YouTuber did an admirable job of assembling the experimental dual-monitor with power, controller boards and plenty of cooling in a thick but serviceable case.
DIY Perks was very clear about the successes of his project, as well as the limitations. The result is a mix of successes and drawbacks.
Upon first boot, the image contrast was said to be impressive, but as windows were opened and text / UI elements were shown on screen a “weird softness” was observed. Softer text was attributed to the dual monitor featuring dual tracing paper layers and was described as a little like a subtle drop shadow effect.
Moving onto gaming, one of the key purposes that this monitor was designed for, Perks was much more happy with the results. He praised the powerful contrast and vivid color. It is hard to catch this kind of effect on camera, and then show it via a medium like YouTube (and screenshots) but the pictures helps show off how the project worked out.
DIY Perks admits a major drawback of the dual-layer design is power consumption. Apparently, the backlight array in the example used 250W. Additionally, the peak brightness of the resulting monitor was somewhat dimmer than a single unmodified sample.
If you want to make one of these DIY dual-layer LCD monitors you can check out some official DIY Perks forum guidance, and there are even suggestions on how to make it better than the video example. One of the most interesting suggestions could lead to elimating at least one of the tracing paper layers.