Display device

Patent metadata

Field	Value
Publication number	US-10078173-B2
Application number	US-201715691142-A
Country	US
Kind code	B2
Filing date	Aug 30, 2017
Priority date	Sep 19, 2016
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

A display device includes a backlight unit and a display panel disposed on the backlight unit. The backlight unit includes a light guide plate including a plurality of charged particles, a light source unit disposed at a side of the light guide plate and providing light to the light guide plate, and a transparent electrode disposed under the light guide plate. Each of the plurality of charged particles includes first and second charged portions which have charge values of which polarities are different from each other. The first charged portion reflects the light received from the light source unit, and the second charged portion absorbs the light received from the light source unit. Positions of the first and second charged portions of each of the plurality of charged particles are controlled based on a voltage applied to the transparent electrode.

First claim

What is claimed is:

1. A display device comprising:
a backlight unit; and
a display panel disposed on the backlight unit,
wherein the backlight unit comprises:
a light guide plate including a plurality of charged particles;
a light source unit disposed at a side of the light guide plate and which provides light to the light guide plate; and
a transparent electrode disposed under the light guide plate,

wherein each of the plurality of charged particles comprises a first charged portion and a second charged portion which have charge values of which polarities are different from each other,
wherein the first charged portion reflects the light received from the light source unit,
wherein the second charged portion absorbs the light received from the light source unit, and
wherein positions of the first and second charged portions of each of the plurality of charged particles are controlled based on a voltage applied to the transparent electrode.

2. The display device of claim 1 , wherein the first charged portion has a positive charge value, and
wherein the second charged portion has a negative charge value.

3. The display device of claim 1 ,
wherein the backlight unit further comprises a reflection sheet disposed under the light guide plate,
wherein the light guide plate includes a plurality of areas,
wherein each of the plurality of areas operates in a first mode where the charged particles in the area reflects the light received from the light source unit or in a second mode where the charged particles in the area absorbs the light received from the light source unit,
wherein, in the first mode, the first charged portion of the charged particles in the area faces the display panel and the second charged portion of the charged particles in the area faces the reflection sheet, and
wherein, in the second mode, the second charged portion of the charged particles in the area faces the display panel and the first charged portion of the charged particles in the area faces the reflection sheet.

4. The display device of claim 1 , wherein the light guide plate comprises:
a light incident surface on which the light is incident;
an opposite surface opposite to the light incident surface;
a light exit surface which connects the light incident surface and the opposite surface; and
a rear surface opposite to the light exit surface,
wherein the plurality of charged particles is disposed to be adjacent to the rear surface.

5. The display device of claim 1 , wherein a surface of each of the plurality of charged particles is divided into a white surface and a black surface,
wherein the first charged portion includes the white surface, and
wherein the second charged portion includes the black surface.

6. The display device of claim 1 , wherein the first charged portion includes a white pigment, and
wherein the second charged portion includes a black pigment.

7. The display device of claim 1 , further comprising:
a protective layer which surrounds each of the plurality of charged particles.

8. The display device of claim 1 , wherein the light source unit comprises:
a printed circuit board; and
a plurality of light sources spaced apart from each other on the printed circuit board,
wherein the plurality of light sources is driven independently of each other.

9. The display device of claim 1 , wherein the transparent electrode comprises a plurality of sub-transparent electrodes spaced apart from each other, and
wherein the plurality of sub-transparent electrodes is controlled independently of each other.

10. The display device of claim 9 , wherein each of the plurality of sub-transparent electrodes has a rod shape when viewed in a plan view.

11. The display device of claim 9 , wherein each of the plurality of sub-transparent electrodes has a square shape when viewed in a plan view.

12. The display device of claim 1 ,
wherein the backlight unit further comprises a reflection sheet disposed under the light guide plate, and
wherein the transparent electrode is disposed on a top surface of the reflection sheet.

13. The display device of claim 1 ,
wherein the backlight unit further comprises a reflection sheet disposed under the light guide plate, and
wherein the transparent electrode is disposed on a bottom surface of the reflection sheet.

14. The display device of claim 13 , further comprising:
a sealing layer disposed on the bottom surface of the reflection sheet and which covers the transparent electrode.

15. The display device of claim 4 , wherein a distribution density of the plurality of charged particles progressively increases from the light incident surface toward the opposite surface.

Assignees

• Samsung Display Co Ltd

Inventors

• You Junwoo
• Lee Taeho
• Oh Sunhee

Classifications

• G02B6/0081

  Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging · CPC title

• G02B6/0055 Primary

  Reflecting element, sheet or layer · CPC title

• G02B6/0035

  provided on the surface of the light guide or in the bulk of it · CPC title

• G02B6/357

  Electrostatic force (electrostatic forces controlling reflecting elements in general G02B26/0841) · CPC title

• G02B6/3512

  the optical element being reflective, e.g. mirror · CPC title