LED backlight and liquid crystal display device using thereof
First Claim
1. A backlight comprising:
- a light guide plate;
a light diffusing optical waveguide disposed adjacent said light guide plate;
a plurality of white LEDs disposed on said light diffusing optical waveguide such that said light diffusing optical waveguide is sandwiched between said plurality of white LEDs and said light guide plate, said plurality of white LEDs emitting a white light that propagates through the light diffusing optical wave guide toward a side of said light guide plate;
a single color LED disposed on a different side of said light diffusing optical waveguide than a side of said light diffusing optical waveguide on which said plurality of white LEDs are disposed, said single color LED emitting a single color light that propagates through said light diffusing optical waveguide to said light guide plate; and
a light diffusing portion disposed on a portion of said light diffusing optical waveguide where the plurality of white LEDs are not disposed for diffusing the single color light as the single color light propagates through said light diffusing optical waveguide,wherein the single color light from the single color LED is directed to turn into the light guide plate at the light diffusing portion disposed on said light diffusing optical waveguide,wherein the portion of said light diffusing optical waveguide on which said light diffusing portion is disposed does not oppose the side of said light diffusing optical waveguide on which the white LEDs are disposed, andwherein said light diffusing optical waveguide has grooves formed in a side thereof facing said light guide plate, said grooves being spaced more closely at a center portion of said light diffusing optical waveguide than at the side on which the single color LED is disposed.
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Abstract
An object of the present invention is to improve the color reproduction capability of a liquid crystal display backlight using white LEDs.
A backlight of the present invention includes: a light guide plate 6; a light diffusing optical waveguide 3 disposed adjacent the light guide plate 6; a plurality of white LEDs 1 disposed on the light diffusing optical waveguide 3; and single color LEDs (red LEDs) 2 disposed on respective opposite sides of the light diffusing optical waveguide 3; wherein light from the white LEDs 1 passes through the light diffusing optical waveguide 3 and enters the light guide plate 6 through a side thereof, whereas light from the single color LEDs 2 is diffused by the light diffusing optical waveguide 3 before entering the light guide plate 6 through the same side thereof. Thus, the light diffusing optical waveguide 3 mixes light from the white LEDs 1 and single color LEDs 2, resulting in improved color reproduction capability of the backlight.
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Citations
15 Claims
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1. A backlight comprising:
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a light guide plate; a light diffusing optical waveguide disposed adjacent said light guide plate; a plurality of white LEDs disposed on said light diffusing optical waveguide such that said light diffusing optical waveguide is sandwiched between said plurality of white LEDs and said light guide plate, said plurality of white LEDs emitting a white light that propagates through the light diffusing optical wave guide toward a side of said light guide plate; a single color LED disposed on a different side of said light diffusing optical waveguide than a side of said light diffusing optical waveguide on which said plurality of white LEDs are disposed, said single color LED emitting a single color light that propagates through said light diffusing optical waveguide to said light guide plate; and a light diffusing portion disposed on a portion of said light diffusing optical waveguide where the plurality of white LEDs are not disposed for diffusing the single color light as the single color light propagates through said light diffusing optical waveguide, wherein the single color light from the single color LED is directed to turn into the light guide plate at the light diffusing portion disposed on said light diffusing optical waveguide, wherein the portion of said light diffusing optical waveguide on which said light diffusing portion is disposed does not oppose the side of said light diffusing optical waveguide on which the white LEDs are disposed, and wherein said light diffusing optical waveguide has grooves formed in a side thereof facing said light guide plate, said grooves being spaced more closely at a center portion of said light diffusing optical waveguide than at the side on which the single color LED is disposed. - View Dependent Claims (2, 3, 4, 5)
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6. A liquid crystal display device comprising:
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a white LED backlight; and a display panel for controlling light from said backlight to display an image; wherein said backlight comprises; a light guide plate; a light diffusing optical waveguide disposed adjacent said light guide plate; a plurality of white LEDs disposed on said light diffusing optical waveguide such that said light diffusing optical waveguide is sandwiched between said plurality of white LEDs and said light guide plate, said plurality of white LEDs emitting a white light that propagates through the light diffusing optical wave guide toward a side of said light guide plate; a single color LED disposed on a different side of said light diffusing optical waveguide than a side of said light diffusing optical waveguide on which said plurality of white LEDs are disposed, said single color LED emitting a single color light that propagates through said light diffusing optical waveguide to said light guide plate; and a light diffusing portion disposed on a portion of said light diffusing optical waveguide where the plurality of white LEDs are not disposed for diffusing the single color light as the single color light propagates through said light diffusing optical waveguide, wherein the single color light from the single color LED is directed to turn into the light guide plate at the light diffusing portion disposed on said light diffusing optical waveguide, wherein the portion of said light diffusing optical waveguide on which said light diffusing portion is disposed does not oppose the side of said light diffusing optical waveguide on which the white LEDs are disposed, and wherein said light diffusing optical waveguide has grooves formed in a side thereof facing said light guide plate, said grooves being spaced more closely at a center portion of said light diffusing optical waveguide than at the side on which the single color LED is disposed. - View Dependent Claims (7, 8, 9)
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10. A backlight comprising:
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a light guide plate; a light diffusing optical waveguide disposed adjacent said light guide plate; a plurality of white LEDs disposed on said light diffusing optical waveguide such that said light diffusing optical waveguide is sandwiched between said plurality of white LEDs and said light guide plate, said plurality of white LEDs emitting a white light that propagates through the light diffusing optical wave guide toward a side of said light guide plate; a single color LED disposed on a different side of said light diffusing optical waveguide than a side of said light diffusing optical waveguide on which said plurality of white LEDs are disposed, said single color LED emitting a single color light that propagates through said light diffusing optical waveguide to said light guide plate; and a metal substrate having reflective properties; wherein said light diffusing optical waveguide, said plurality of white LEDs, and said single color LED are formed on said reflective metal substrate, and wherein a light diffusing portion is disposed on a portion of said light diffusing optical waveguide where the plurality of white LEDs are not disposed for diffusing the single color light as the single color light propagates through said light diffusing optical waveguide, wherein the single color light from the single color LED is directed to turn into the light guide plate at the light diffusing portion disposed on said light diffusing optical waveguide, wherein the portion of said light diffusing optical waveguide on which said light diffusing portion is disposed does not oppose the side of said light diffusing optical waveguide on which the white LEDs are disposed, and wherein said light diffusing optical waveguide has grooves formed in a side thereof facing said light guide plate, said grooves being spaced more closely at a center portion of said light diffusing optical waveguide than at the side on which the single color LED is disposed. - View Dependent Claims (11, 12)
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13. A liquid crystal display device comprising:
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a white LED backlight; and a display panel for controlling light from said backlight to display an image; wherein said backlight comprises; a light guide plate; a light diffusing optical waveguide disposed adjacent said light guide plate; a plurality of white LEDs disposed on said light diffusing optical waveguide such that said light diffusing optical waveguide is sandwiched between said plurality of white LEDs and said light guide plate, said plurality of white LEDs emitting a white light that propagates through the light diffusing optical wave guide toward a side of said light guide plate; a single color LED disposed on a different side of said light diffusing optical waveguide than a side of said light diffusing optical waveguide on which said plurality of white LEDs are disposed, said single color LED emitting a single color light that propagates through said light diffusing optical waveguide to said light guide plate; and a metal substrate having reflective properties; wherein said light diffusing optical waveguide, said plurality of white LEDs, and said single color LED are formed on said reflective metal substrate, wherein a light diffusing portion is disposed on a portion of said light diffusing optical waveguide where the plurality of white LEDs are not disposed for diffusing the single color light as the single color light propagates through said light diffusing optical waveguide, wherein the single color light from the single color LED is directed to turn into the light guide plate at the light diffusing portion disposed on said light diffusing optical waveguide, and wherein the portion of said light diffusing optical waveguide on which said light diffusing portion is disposed does not oppose the side of said light diffusing optical waveguide on which the white LEDs are disposed, and wherein said light diffusing optical waveguide has grooves formed in a side thereof facing said light guide plate, said grooves being spaced more closely at a center portion of said light diffusing optical waveguide than at the side on which the single color LED is disposed. - View Dependent Claims (14, 15)
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Specification