Backlight unit including array of hyperbolically-shaped micro lenses

Patent metadata

Field	Value
Publication number	US-9581735-B2
Application number	US-201214359032-A
Country	US
Kind code	B2
Filing date	Jan 13, 2012
Priority date	Jan 13, 2012
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

A backlight unit includes a light source and a two-dimensional micro lens array (MLA) sheet including a plurality of lens unit each having a conic lens shape with a cross-section, taken through the lens axis, having a shape defined by the equation:

y
=

x
2

/
r

1
+

1
-

(

1
+
k

)

⁢

(

1
/
r

)

2

⁢

x
2

where k is a constant with a value of less than or equal to −1, and r is the radius of curvature at the peak of the lens unit.

First claim

The invention claimed is:

1. A backlight unit comprising:
a light source; and
a micro lens array (MLA) sheet comprising a plurality of lens units two-dimensionally arranged thereon,
wherein the light source has the micro lens array (MLA) sheet, a prism sheet, and a reflective polarizing film, sequentially stacked thereon or,
wherein the light source has a prism sheet, the micro lens array (MLA) sheet, and a reflective polarizing film, sequentially stacked thereon,
wherein each lens unit has a conic lens shape of which a vertical cross-section taken in a lens center is represented by the following Expression 1:

y
=

x
2

/
r

1
+

1
-

(

1
+
k

)

⁢

(

1
/
r

)

2

⁢

x
2

[

Expression
⁢

⁢
1

]

where k is a conic constant, and r is a radius of curvature at a peak of the lens unit, wherein, k≦−1.

2. The backlight unit of claim 1 , wherein the conic constant k is −3 to −1.

3. The backlight unit of claim 1 , wherein the lens unit has a hyperbolic or parabolic vertical cross-section.

4. The backlight unit of claim 1 , wherein a pitch between the lens units is 10 to 500 μm.

5. The backlight unit of claim 1 , wherein a bottom diameter of the lens unit is 90 to 116% of a pitch between the lens units.

6. The backlight unit of claim 1 , wherein a radius of curvature at a peak of the lens unit is 0.2 to 26% of a pitch between the lens units.

7. The backlight unit of claim 1 , wherein the plurality of lens units are arranged in a honeycomb structure.

8. The backlight unit of claim 1 , wherein the micro lens array (MLA) sheet includes two micro lens array (MLA) sheets.

9. The backlight unit of claim 1 , further comprising at least one selected from a group consisting of a prism sheet, a lenticular lens sheet, a diffusion sheet, and a reflective polarizing film.

10. The backlight unit of claim 1 , wherein the light source has a diffusion sheet and the micro lens array (MLA) sheet, sequentially stacked thereon.

11. The backlight unit of claim 1 , wherein the light source has a diffusion sheet and two layers of the micro lens array (MLA) sheet, sequentially stacked thereon.

12. The backlight unit of claim 1 , wherein the light source has a diffusion sheet, a prism sheet, and the micro lens array (MLA) sheet, sequentially stacked thereon.

13. The backlight unit of claim 1 , wherein the light source has a diffusion sheet, a lenticular sheet, and the micro lens array (MLA) sheet, sequentially stacked thereon.

14. The backlight unit of claim 1 , wherein the light source has a lenticular sheet, a prism sheet, and the micro lens array (MLA) sheet, sequentially stacked thereon.

Assignees

• Kim Byoung-Mook
• Park Kwang-Seung
• Park Byung-Su
• Kim Yune-Hyoun
• Han Sang-Choll
• Kim Jin-Hyun
• Lg Chemical Ltd

Inventors

• Kim Byoung-Mook
• Park Kwang-Seung
• Park Byung-Su
• Kim Yune-Hyoun
• Han Sang-Choll
• Kim Jin-Hyun

Classifications

• G02F2001/133607

  Physics · mapped topic

• G02B3/005 Primary

  arranged along a single direction only, e.g. lenticular sheets (G02B3/0043 takes precedence) · CPC title

• G02B3/0056 Primary

  arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses (G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085) · CPC title

• G02B5/045

  Prism arrays · CPC title

• G02F1/133607

  the light controlling member including light directing or refracting elements, e.g. prisms or lenses · CPC title