Many of today’s televisions, smart phones, and tablets use LCD or OLED devices that are limited to displaying 35% or less of the visible color spectrum. For consumers, this translates into a viewing experience significantly different to what they experience in the real world. Using a customized phosphor-based optical enhancement film (ROEF) along with a blue LED, OLED or microLED display, it becomes possible to achieve a wider color gamut. This constitutes a major improvement to most current portable devices. These phosphor films can be economically produced using roll-to-roll manufacturing compatible with solid state lighting and large area flexible displays.
The figures below show some typical spectra achieved using red/green ROEF enhancement films coupled to a blue LED. Only two phosphors were used in these films, a green phosphor and a red phosphor. For microLED displays, such red and green phosphors can also be used to enable full-color RGB devices and generally have superior properties (brightness and stability) compared to quantum dots (QDs). Unlike conventional QDs, these phosphors are environmentally-friendly and do not contain any heavy metals.
Phosphor Technology for microLED, OLED, and LCD displays
When combined with standard LCD color filters, the phosphor-based ROEF can deliver a color gamut equivalent to more than 100% of NTSC under the 1976 u’,v’ color space.The color saturation achieved by phosphor-based ROEF can be significantly better compared to the color space of the sRGB primaries achieved by higher end display products utilizing conventional white LEDs. The color gamut can be further improved and optimized by using different LEDs, phosphors, and color filters in order to deliver even more saturated colors. A similar level of performance is also possible for microLED display technology. Particle size can be made small enough to enable a wide range of micro printing, depending on the required display resolution.
High Color Gamut microLED and LCD Displays are Possible using Phosphors (154% of sRGB)
NTSC and sRGB comparison with Phosphor Enhancement Film