Backlighting apparatus for uniformly illuminating a display panel
First Claim
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1. An apparatus, comprising:
- a display panel having a rear surface and a front surface, said display panel being at least partially transmissive such that at least a portion of illumination on said rear surface is transmitted to said front surface;
a light source for backlighting said display panel, said light source comprising;
a light bulb;
a housing having diffusive reflective interior surfaces forming a fluid-containing cavity, said cavity having a depth, said bulb mounted in said cavity with said interior surfaces of said cavity spaced therefrom, said housing having an aperture which opens into said cavity, said aperture juxtaposed with said rear surface of said display panel to illuminate said rear surface, said cavity having a diffusive reflective surface area and said aperture having an area, the ratio of said area of said aperture to the sum of (i) said area of said aperture and (ii) said surface area of said cavity being at least 0.05, said aperture having a bisector dimension, the ratio of said depth to said bisector dimension being at least 0.1;
a diffuser at said aperture, said diffuser positioned to diffuse illumination which passes through said aperture from said cavity toward said display panel;
a brightness enhancing material disposed between said diffuser and said display panel, said material providing illumination within a maximal viewing angle and reflecting illumination outside said maximal viewing angle.
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Abstract
A light source having a light bulb disposed within a cavity having diffusely reflecting walls and an aperture for backlighting a display is disclosed. The ratio of aperture area to cavity surface area is maximized. A diffuser and brightness enhancing film are situated at the opening of the aperture between the aperture and the display to be backlit. A color filter may also be employed to whiten the light emerging from the light source.
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Citations
21 Claims
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1. An apparatus, comprising:
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a display panel having a rear surface and a front surface, said display panel being at least partially transmissive such that at least a portion of illumination on said rear surface is transmitted to said front surface; a light source for backlighting said display panel, said light source comprising; a light bulb; a housing having diffusive reflective interior surfaces forming a fluid-containing cavity, said cavity having a depth, said bulb mounted in said cavity with said interior surfaces of said cavity spaced therefrom, said housing having an aperture which opens into said cavity, said aperture juxtaposed with said rear surface of said display panel to illuminate said rear surface, said cavity having a diffusive reflective surface area and said aperture having an area, the ratio of said area of said aperture to the sum of (i) said area of said aperture and (ii) said surface area of said cavity being at least 0.05, said aperture having a bisector dimension, the ratio of said depth to said bisector dimension being at least 0.1; a diffuser at said aperture, said diffuser positioned to diffuse illumination which passes through said aperture from said cavity toward said display panel; a brightness enhancing material disposed between said diffuser and said display panel, said material providing illumination within a maximal viewing angle and reflecting illumination outside said maximal viewing angle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus, comprising:
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a display panel; a lamp; a housing having a cavity containing said lamp and having diffusely reflective interior surfaces, said housing having an aperture juxtaposed with said display panel, said lamp and said cavity cooperating to provide a substantially lambertian light source; a diffuser placed at said aperture to increase the uniformity of the illumination emitted through said aperture; and a brightness enhancing material disposed between said diffuser and said display panel, said brightness enhancing material emitting light propagating through said aperture along a path within a viewing angle, said brightness enhancing material concentrating the illumination of said substantially lambertian source within said viewing angle to increase the brightness of said display panel. - View Dependent Claims (15, 16, 17, 18)
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19. An apparatus, comprising:
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a display panel having a rear surface and a front surface, said display panel being at least partially transmissive such that at least a portion of illumination on said rear surface is transmitted to said front surface; a light source for backlighting said display panel, said light source comprising; a device that emits light; a housing having diffusive reflective interior surfaces forming a cavity, said cavity having a depth, said light emitting device mounted in said cavity, said housing having an aperture which opens into said cavity, said aperture juxtaposed with said rear surface of said display panel to illuminate said rear surface, said cavity having a diffusive reflective surface area and said aperture having an area, the ratio of said area of said aperture to the sum of (i) said area of said aperture and (ii) said surface area of said cavity being at least 0.05, said aperture having a bisector dimension, the ratio of said depth to said bisector dimension being at least 0.1; a diffuser at said aperture, said diffuser positioned to diffuse illumination which passes through said aperture from said cavity toward said display panel; a brightness enhancing material disposed between said diffuser and said display panel, said material concentrating illumination within a viewing angle so as to enhance the brightness of the display panel. - View Dependent Claims (20, 21)
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Specification