micro LED diffuser eliminates the screen door effect
Like standard LEDs, micro LEDs are discrete light sources that require diffusion. However, because mLEDs are smaller than a pixel, diffusion is even more critical due to what’s known as the screen door effect or fine black lines that appear between the pixels.
If you’re 10 or 20 feet away from the display, you’ll likely not notice the lines; however, less than a foot away (e.g., glancing at a smart watch or tablet), the screen door effect can be quite noticeable.
Adding a diffuser film can eliminate the screen door effect, but the diffuser material must be mounted extremely close to the mLEDs in order to avoid internal reflection.
For a diffuser to be effective, however, there needs to be enough distance between the film and the LEDs in order for the light to spread out before the diffuser and after the diffuser. If the screen door is 10 microns wide, you’ll need a 10 micron gap. Because standard bulk diffusers use a random scattering pattern with high back scatter, there will be some light loss; therefore, eliminating the screen door effect will come at the expense of resolution, brightness, and efficiency.
A 100° Micro LED diffuser
Luminit’s 100° Micro LED diffuser (MLD) is based on the principle of surface scatter instead of volume or random scatter. Luminit’s Light Shaping Diffusers (LSDs) are invisible to the naked eye, they consist of holographically recorded LSD microstructures embedded on polyester or polycarbonate film. When applied to a light source, the film conceals and controls the output of an LED light source and spreads the light depending on the angle of distribution (e.g., 100° circular).
These high transmission structures are non-scattering in nature and utilize light that would otherwise be wasted, they have a much higher transmission efficiency (~92%) than conventional diffusers because surface relief scatter is much more efficient. The light hits the diffuser once, resulting in no significant loss of light or display resolution because internal reflection is eliminated.
MLD incorporates a 100° angle FWHM-the widest beam spread available on the market and the closest to a lambertian pattern possible. Even the tiniest point of light will be optimally spread for more even and uniform coverage. Luminit’s MLD also enables designers to build thinner profile displays, which is another critical factor in hand-held or wearables displays where product designers and engineers covet even 10 microns worth of space.
Luminit – www.luminitco.com
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