Surface lighting device and liquid crystal display device using the same

• US 20040218388A1
• Filed: 03/30/2004
• Published: 11/04/2004
• Est. Priority Date: 03/31/2003
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Fujitsu Display Technologies Corporation (Fujitsu Limited)
• Inventors: Suzuki, Toshihiro
• Granted Patent: US 7,281,816 B2
• Time in Patent Office: Days
• US Class Current: 362/231
• CPC Class Codes: F21Y 2107/50 on planar substrates or supports, but arranged in different planes or with differing orientation, e.g. on plate-shaped supports with steps on which light-generating elements are mounted
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G02F 1/133613 characterized by the sequence of light sources
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

The present invention relates to a surface lighting device, in which plural light-emitting elements corresponding to plural colors including at least red, green and blue, that is, LEDs (Light Emitting Diodes) capable of emitting light of primary colors are arranged to form a surface light source, and a liquid crystal display device which attains high luminance even on a large display area by including the surface lighting device. The surface lighting device is characterized by at least including: a surface light source consisting of light-emitting elements corresponding to plural colors at least including three primary colors of light; a reflection plate which is set among the light-emitting elements; a substrate on which the light-emitting elements and the reflection plate are set; and a diffusion plate which is located above the light-emitting elements and the reflection plate, and in that the light-emitting elements are arranged with a cover rate of the substrate by the reflection plates improved or an irradiation angle, at which an amount of light of the light-emitting elements corresponding to at least one color is maximized, is set according to an interval between the diffusion plate and the substrate.

Claims

1. A surface lighting device comprising:

a surface light source in which linear light sources having light-emitting elements, which corresponds to respective colors among combinations of plural colors at least including three primary colors of light, arranged in series are arranged in a predetermined order;

a reflection plate which is laid so as to fill spaces among the light-emitting elements constituting the linear light sources;

a substrate on which the surface light source and the reflection plate are set; and

a diffusion plate which is located above the surface light source and the reflection plate,

wherein non-light-emitting portions of the light emitting elements are covered by the reflection plate.

8. A liquid crystal display device comprising:

a surface lighting device according to claim 1;

and

a liquid crystal display panel.

2. A surface lighting device comprising:

a surface light source in which linear light sources having light-emitting elements, which corresponds to respective colors among combinations of plural colors at least including three primary colors of light, arranged in series are arranged in a predetermined order and at a fixed interval;

a first reflection plate which is laid so as to fill spaces among the light-emitting elements constituting the linear light sources;

a second reflection plate having through-holes in which light-emitting portions of the light-emitting elements can be fit;

a substrate on which the surface light source, the first reflection plate and the second reflection plate are set; and

a diffusion plate which is located above the surface light source, the first reflection plate and the second reflection plate,

wherein non-light-emitting portions of the light-emitting elements are covered by the second reflection plate.

3. A surface lighting device comprising:

a surface light source in which linear light sources having light-emitting elements, which corresponds to respective colors among combinations of plural colors including at least three primary colors of light, arranged in series are arranged in a predetermined order;

a reflection plate which is laid so as to fill spaces among the light-emitting elements constituting the linear light sources;

a substrate which has linear projected portions arranged at a fixed interval and on which the surface light source and the reflection plate are set; and

a diffusion plate which is located above the surface light source and the reflection plate,

wherein the linear light sources are arranged on slopes or sides of the linear projected portions arranged at the fixed interval on the substrate, and

an irradiation angle, at which an amount of light of the light-emitting elements corresponding to at least one color among the plural colors is maximized according to the interval of the linear projected portions and an interval between the diffusion plate and the substrate, is set according to an angle of the slopes or the sides of the linear projected portions.

5. A surface lighting device according to claim 3,

wherein, in the case in which it is assumed that the interval for setting the linear light sources corresponding to one color is a fixed value L and an interval between the diffusion plate and a plane on which the liner light sources are set is a fixed value H, the irradiation angle, at which an amount of light of the linear light sources is maximized, is set such that a relation of L≦

2×

H×

tan (irradiation angle at which an amount of light of the linear light sources is maximized) is satisfied.

4. A surface lighting device comprising:

a surface light source in which linear light sources having light-emitting elements, which corresponds to respective colors among combinations of plural colors at least including three primary colors of light, arranged in series are arranged in a predetermined order and at a fixed interval;

light irradiation angle correcting means in light-emitting portions or on the light emitting portions of the light-emitting elements;

a reflection plate which is laid so as to fill spaces among the light-emitting elements constituting the linear light sources;

a substrate on which the linear light sources and the reflection plate are set; and

a diffusion plate which is located above the linear light sources and the reflection plate,

wherein an irradiation angle, at which an amount of light is maximized, is set by the light irradiation angle correcting means on the light-emitting portion of the linear light sources corresponding to at least one color among the plural colors according to the interval of the linear light sources and an interval between the diffusion plate and the substrate.

6. A surface lighting device comprising:

a surface light source in which light-emitting element groups having three light-emitting elements, which correspond to three primary colors of light, arranged to be contiguous with vertexes of a triangle are arranged in a matrix shape;

a substrate on which the light-emitting element groups are arranged; and

a diffusion plate which is located above the surface light source,

wherein the light-emitting element groups are arranged to be deviated every other column or row such that a positional relation among the light-emitting element groups is a delta shape, and

a row interval, a column interval, and an arrangement angle of the light-emitting element groups are adjusted such that, when it is assumed that an average sum of amounts of light calculated from a sum of amounts of light of the single color light-emitting elements is 100%, a sum of amounts of light of the respective single color light-emitting elements at a center of gravity of the delta shape and a center of gravity of a diamond shape formed by two delta shapes is between 75% and 125%.

7. A surface lighting device comprising:

linear light sources in which light-emitting element groups having three light-emitting elements, which correspond to three primary colors of light, are arranged in series to be contiguous with each other;

light irradiation angle correcting means in light-emitting portions or on the light emitting portions of the light-emitting elements;

a substrate on which the light-emitting element groups are arranged; and

a diffusion plate which is located above the surface light source,

wherein the linear light sources are arranged in plural columns to form a surface light source, and

a maximum irradiation angle of the light-emitting elements is corrected such that a point where a maximum irradiation direction of the light-emitting elements, which is corrected by the light irradiation angle correcting means in the light-emitting portions or on the light-emitting portions of the light-emitting elements constituting the linear light source of attention, and the diffusion plate cross with each other goes beyond a middle point of the linear light source adjacent to the linear light source of attention.