LIGHT GUIDE BODY, LIGHTING DEVICE HAVING LIGHT GUIDE BODY, AND DISPLAY DEVICE

• US 20130242610A1
• Filed: 11/25/2011
• Published: 09/19/2013
• Est. Priority Date: 11/29/2010
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: OCHI, Takashi, SHIBASAKI, Masakazu, AOYAMA, Iori, IYAMA, Yuichi, KIKUCHI, Katsuhiro
• Granted Patent: US 9,128,220 B2
• Time in Patent Office: Days
• US Class Current: 362/611
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G02B 6/0011 the light guides being planar or of plate-like form
• CPC Class Codes: G02B 6/0033 Means for improving the coupling-out of light from the light guide
• CPC Class Codes: 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
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A light guiding element has a first principal surface, a second principal surface which opposes the first principal surface, a first lateral surface which intersects with the first principal surface and the second principal surface, and a second lateral surface which opposes the first lateral surface. The light guiding element allows light incoming from the first lateral surface to propagate between the first principal surface and the second principal surface. The light guiding element includes a portion in which a refractive index varies substantially continuously from the first principal surface toward the second principal surface.

Claims

1. A light guiding element having a first principal surface, a second principal surface which opposes the first principal surface, a first lateral surface which intersects with the first principal surface and the second principal surface, and a second lateral surface which opposes the first lateral surface, the light guiding element being capable of allowing light incoming from the first lateral surface to propagate between the first principal surface and the second principal surface,

wherein the light guiding element includes a portion in which a refractive index varies substantially continuously from the first principal surface toward the second principal surface.

2. The light guiding element of claim 1, wherein the light guiding element has a plurality of raised portions which are two-dimensionally arranged between the first principal surface and the second principal surface.

3. The light guiding element of claim 2, wherein a two-dimensional size of the plurality of raised portions is not less than 10 nm and not more than 500 nm, and a distance between adjacent ones of the plurality of raised portions is not less than 10 nm and not more than 500 nm.

4. The light guiding element of claim 2, wherein the plurality of raised portions are protruding from the second principal surface toward the first principal surface.

5. The light guiding element of claim 2, wherein gaps between adjacent raised portions are filled with a material whose refractive index is lower than that of a material of the plurality of raised portions.

6. The light guiding element of claim 2, wherein gaps between plural ones of the plurality of raised portions which are provided on a side that is closest to the first principal surface are filled with air.

7. The light guiding element of claim 2, comprising a plurality of light guiding layers between the first principal surface and the second principal surface, the plurality of light guiding layers including a first light guiding layer and a second light guiding layer which is provided on a second principal surface side of the first light guiding layer,

wherein each of the first and second light guiding layers has the plurality of raised portions, and a refractive index n1 of the raised portions of the first light guiding layer is smaller than a refractive index n2 of the raised portions of the second light guiding layer.

8. The light guiding element of claim 2, wherein a volume proportion of the plurality of raised portions is greater on the second lateral surface side than on the first lateral surface side.

9. The light guiding element of claim 8, wherein a height of the plurality of raised portions is greater on the second lateral surface side than on the first lateral surface side.

10. The light guiding element of claim 8, wherein a number of the plurality of raised portions is greater on the second lateral surface side than on the first lateral surface side.

11. A lighting device, comprising:

the light guiding element as set forth in claim 1; and

a light source which is provided so as to emit light toward the first lateral surface of the light guiding element.

12. A display device, comprising:

the lighting device as set forth in claim 11; and

a display panel.

13. The display device of claim 12, wherein the lighting device is provided on a viewer side of the display panel.