Liquid crystal display including dielectric mirror for recycling light
An electronic display comprises a backlight unit and a liquid crystal (LC) layer, where the backlight combines and directs light from a plurality of light sources towards the LC layer, which controls an amount of light to be displayed. The LC layer is controlled by a plurality of thin-film transistors (TFT) disposed on a TFT layer. To prevent light from the backlight from being absorbed by the TFTs, a dielectric mirror is disposed between the transistors and the backlight unit to reflect light from the backlight unit that is projectors towards the transistors back towards the backlight unit. Hence, light can be recycled and travel through an aperture between the dielectric mirrors, thereby improving luminance.
1. An electronic display device comprising:
a backlight unit configured to project light;
a liquid crystal layer configured to receive light from the backlight unit and to control an amount of light from the backlight unit that passes through the liquid crystal layer;
a thin film transistor (TFT) layer disposed between the backlight unit and the liquid crystal layer, the TFT layer comprising one or more TFTs each configured to cause a portion of the liquid crystal layer to control an amount of light that passes through the respective portion of the liquid crystal layer; and
one or more dielectric mirrors each facing the backlight unit and disposed on a surface of one of the TFTs, and configured to reflect light from the backlight unit projected towards the TFTs back towards the backlight unit.
2. The electronic display device of claim 1 , wherein the TFT layer further comprises a transparent TFT substrate disposed between the one or more TFTs and the backlight unit, and wherein each of the one or more dielectric mirrors is formed between the TFT substrate and its respective TFT.
3. The electronic display device of claim 1 , wherein each dielectric mirror has a width larger than that of its corresponding TFT.
4. The electronic display device of claim 1 , further comprising a color filter layer comprising one or more color filters each corresponding to a subpixel of the display and configured to pass through a portion of the light of the backlight unit of a particular color.
5. The electronic display device of claim 4 , further comprising one or more black matrix sections comprising a light-absorbent material, wherein the one or more black matrix sections are positioned based upon locations of the one or more TFTs of the TFT layer.
6. The electronic display device of claim 4 , wherein the one or more color filters are positioned based upon apertures corresponding to spaces of the TFT layer not covered by the one or more dielectric mirrors.
7. The electronic display device of claim 1 , further comprising a polarizing layer configured to polarize light projected by the backlight unit.
8. The electronic display device of claim 1 , wherein the one or more dielectric mirrors comprises a single dielectric mirror covering the TFT layer, the single dielectric mirror having a plurality of openings corresponding to subpixels of the electronic display, each subpixel located in an area between the one or more TFTs of the TFT layer.
9. The electronic display device of claim 1 , wherein the one or more dielectric mirrors comprise a material having substantially no metallic property.
10. The electronic display device of claim 1 , wherein the one or more dielectric mirrors comprise a plurality of stacked layers.
11. The electronic display device of claim 10 , wherein the plurality of stacked layers comprises alternating silicon oxide and silicon nitride layers.
12. The electronic display device of claim 1 , wherein the one or more dielectric mirrors comprise a silicon oxide, silicon nitride, or titanium oxide material.
13. The electronic display device of claim 1 , wherein the one or more dielectric mirrors have a uniform height based upon a target wavelength of light from the backlight unit.