Thin hollow backlights with beneficial design characteristics
First Claim
1. An edge-lit backlight, comprising:
- a front and back reflector forming a hollow light recycling cavity having a cavity depth H and an output region of area Aout; and
one or more light sources disposed proximate a periphery of the backlight to emit light into the light recycling cavity, the light sources having an average plan view source separation of SEP and collectively having an active emitting area Aemit;
wherein a first parameter equals Aemit/Aout;
wherein a second parameter equals SEP/H;
wherein the backlight is characterized by the first parameter being in a range from 0.0001 to 0.1, and by the second parameter being in a range from 3 to 10; and
wherein the front reflector has a hemispherical reflectivity for unpolarized visible light of Rfhemi, and the back reflector has a hemispherical reflectivity for unpolarized visible light of Rbhemi, and (1−
Rfhemi)/(1−
Rbhemi) is at least 10.
1 Assignment
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Accused Products
Abstract
A front and back reflector are arranged to form a hollow light recycling cavity having an output region, and one or more light sources (e.g. LEDs) are disposed to emit light into the cavity. In one aspect, the back reflector has a design characterized by a first and second parameter. The first design parameter is a ratio of the collective emitting area of the light sources Aemit to the area of the output region Aout, and Aemit/Aout is preferably from 0.0001 to 0.1. The second design parameter is SEP/H, where H is the depth of the recycling cavity, and SEP is an average plan view source separation associated with the light sources. Other aspects of the disclosed extended area light sources are also described.
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Citations
17 Claims
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1. An edge-lit backlight, comprising:
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a front and back reflector forming a hollow light recycling cavity having a cavity depth H and an output region of area Aout; and one or more light sources disposed proximate a periphery of the backlight to emit light into the light recycling cavity, the light sources having an average plan view source separation of SEP and collectively having an active emitting area Aemit; wherein a first parameter equals Aemit/Aout; wherein a second parameter equals SEP/H; wherein the backlight is characterized by the first parameter being in a range from 0.0001 to 0.1, and by the second parameter being in a range from 3 to 10; and
wherein the front reflector has a hemispherical reflectivity for unpolarized visible light of Rfhemi, and the back reflector has a hemispherical reflectivity for unpolarized visible light of Rbhemi, and (1−
Rfhemi)/(1−
Rbhemi) is at least 10. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A backlight, comprising:
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a front and back reflector forming a hollow light recycling cavity having an output region; and a number N of light sources disposed to emit light into the light recycling cavity, the N light sources including a subset of M light sources that are adjacent to each other, where M is at least 10% of N, or is at least 2, or both; wherein the backlight exhibits a VESA brightness uniformity value over its output region of at least 50% both when all N light sources are energized and when all of the M light sources are selectively turned off;
wherein the front reflector has a hemispherical reflectivity for unpolarized visible light of Rfhemi, and the back reflector has a hemispherical reflectivity for unpolarized visible light of Rbhemi, and (1−
Rfhemi)/(1−
Rbhemi) is at least 10. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification