# US 10,310,164 B2 · Display backlight having lightguide with variable density light extraction elements

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- Number: US 10,310,164 B2
- Document ID: US10310164B2
- Status: Granted
- Kind: B2
- Application number: 15/533,946
- Filed: 2015-12-03
- Published: 2017-12-21
- Granted: 2019-06-04
- Earliest claimed: 2014-12-10
- Assignees: Sharp Kabushiki Kaisha
- Applicants: Sharp Kabushiki Kaisha
- Inventors: Yoshinobu Hirayama; Takao Imaoku; Shugo Yagi
- Web page: https://patentgrep.com/patent/US10310164B2

## CPC

- G02B 6/0055: {Reflecting element, sheet or layer}
- G02B 6/0036: {2-D arrangement of prisms, protrusions, indentations or roughened surfaces}
- G02B 6/0053: {Prismatic sheet or layer; Brightness enhancement element, sheet or layer}
- G02B 6/0061: {to provide homogeneous light output intensity}
- G02B 6/0085: {Means for removing heat created by the light source from the package}
- G02B 6/0091: {of the light source relative to the light guide (G02B6/0021 takes precedence)}
- G02F 1/133308: {Support structures for LCD panels, e.g. frames or bezels}
- G02F 1/13338: {Input devices, e.g. touch panels}
- G02F 1/133502: {Antiglare, refractive index matching layers}
- G02F 1/133514: {Colour filters}
- G02F 1/136286: {Wiring, e.g. gate line, drain line}
- G02F 1/1368: in which the switching element is a three-electrode device {(G02F1/136277 takes precedence)}
- G02B 6/0038: {Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide}
- G02B 6/0088: {of the light guide or other optical sheets in the package}
- G02B 6/009: {of the light source in the package (G02B6/0021 takes precedence)}
- G02F 1/133302: {Rigid substrates, e.g. inorganic substrates}
- G02F 1/133331: {Cover glasses}
- G02F 1/133512: {Light shielding layers, e.g. black matrix (G02F1/136209 takes precedence)}
- G02F 1/133528: {Polarisers}
- G02F 1/1337: Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F 1/13629: {Multilayer wirings}
- G02F 2201/123: pixel
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

A lighting device includes a light guide plate, a plurality of LEDs positioned to project light into a first side surface of the light guide plate, a reflection sheet facing a bottom surface of the light guide plate, a plurality of reflective elements on a light exit surface of the light guide plate opposite the bottom surface and extending in a direction parallel to the first side surface, and a plurality of convex elements on the bottom surface of the light guide plate. The density of the convex elements increases with increasing distance from the light source.

## Claims

### Claim 1

A lighting device comprising:
a light source;
a rectangular light guide plate having a top surface, a bottom surface, and a plurality of peripheral edge surfaces, the light source arranged to project light into a first of the peripheral edge surfaces;
a reflecting member arranged proximate the bottom surface of the light guide plate, and configured to reflect back to the bottom surface light exiting from such bottom surface;
a plurality of reflecting elements disposed on the top surface of the light guide plate, each of the reflecting elements extending in a first direction parallel to the first peripheral edge surfaces of the light guide plate, the plurality of reflecting elements arranged at intervals in a second direction orthogonal to the first peripheral edge surface, the reflecting elements configured to help cause light travelling within the light guide plate to exit through the top surface of the light guide plate;
a plurality of cylindrical lenses formed on the bottom surface of the light guide plate and arranged in the first direction and extending in the second direction, a first density of the plurality of cylindrical lenses on the bottom surface being lower near the first peripheral edge surface than distal from the first peripheral edge surface; and
a plurality of flat portions formed on the bottom surface of the light guide plate, each flat portion proximate to at least one of the plurality of cylindrical lenses, a second density of the plurality of flat portions on the bottom surface being higher near the first peripheral edge surface than distal from the first peripheral edge surface.

### Claim 2 (depends on 1)

The lighting device according to claim 1, wherein
the plurality of cylindrical lenses include a plurality of single and continuous cylindrical lenses,
the flat portions are disposed between the single and continuous cylindrical lenses along the first direction, and
the single and continuous cylindrical lenses are arranged continuously to each other in the first direction and have different height dimensions.

### Claim 3 (depends on 1)

The lighting device according to claim 1, further comprising a plurality of light exit side light collecting portions disposed on the light exit side, the plurality of light exit side light collecting portions extending in the second direction and arranged in the first direction.

### Claim 4 (depends on 1)

A display device comprising:
the lighting device according to claim 1; and
a display panel configured to display images using light from the lighting device.

### Claim 5 (depends on 1)

The lighting device according to claim 1, wherein
the first density is continuously and gradually increased as is farther away from the first peripheral edge surface along the second direction, and the second density is continuously and gradually decreased as is farther away from the first peripheral edge surface along the second direction.

### Claim 6 (depends on 5)

The lighting device according to claim 5, wherein
the cylindrical lenses and the flat portions extend along an entire area of the bottom surface in the second direction.

### Claim 7 (depends on 5)

The lighting device according to claim 5, wherein
the first density is about 60% in a portion of the light guide plate closest to the first peripheral edge surface, and about 90% in a portion of the light guide plate farthest from the first peripheral edge surface, and
the second density is about 40% in a portion of the light guide plate closest to the first peripheral edge surface, and about 10% in a portion of the light guide plate farthest from the first peripheral edge surface.

### Claim 8 (depends on 5)

The lighting device according to claim 5, wherein
the first density is continuously and gradually increased and the second density is continuously and gradually decreased, from the first peripheral edge surface to an opposite second peripheral edge surface side with respect to the second direction.

### Claim 9 (depends on 1)

The lighting device according to claim 1, further comprising a plurality of top surface side light collecting portions disposed on the top surface side of the light guide plate, the light plurality of top surface side light collecting portions extending in the second direction and arranged in the first direction.

### Claim 10 (depends on 9)

The lighting device according to claim 9, wherein the plurality of top surface side collecting portions include prisms each having an apex angle of 100°.

### Claim 11 (depends on 9)

The lighting device according to claim 9, wherein the plurality of reflecting elements include separated reflecting elements arranged at intervals in the first direction.

### Claim 12 (depends on 11)

The lighting device according to claim 11, wherein the plurality of reflecting elements are formed by cutting off a part of a top portion of each of the light collecting portions.

### Claim 13 (depends on 9)

The lighting device according to claim 9, wherein the plurality of top surface side light collecting portions the light exit include prisms each having an apex angle within a range from 135° to 155°.

### Claim 14 (depends on 13)

The lighting device according to claim 13, wherein the prisms each having an apex angle of 150°.