Display device and mobile terminal

Patent metadata

Field	Value
Publication number	US-2016266302-A1
Application number	US-201514808868-A
Country	US
Kind code	A1
Filing date	Jul 24, 2015
Priority date	Mar 12, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

A display device including a liquid crystal panel configured to selectively transmit light for each pixel of the liquid crystal panel; a light guide plate provided behind the liquid crystal panel; a light source array including a plurality of LEDs arranged in a row at first lateral side of the light guide plate, and configured to emit light to the first lateral side of the light guide plate; and a mirror provided in a second lateral side of the light guide plate and configured to reflect the light having reached the second lateral side back along the light guide plate. Further, a rear surface of the light guide plate includes a stepped unevenness having first surfaces configured to reflect light toward the liquid crystal panel and second surfaces configured to reflect light toward the mirror, and a thickness of the light guide plate increases in a first direction from the first lateral side to the second lateral side such that the second lateral side of the light guide plate is thicker than the first lateral side of the light guide plate.

First claim

What is claimed is:

1 . A display device comprising:
a liquid crystal panel configured to selectively transmit light for each pixel of the liquid crystal panel; a light guide plate provided behind the liquid crystal panel; a light source array including a plurality of LEDs arranged in a row at a first lateral side of the light guide plate, and configured to emit light to the first lateral side of the light guide plate; and a mirror provided in a second lateral side of the light guide plate and configured to reflect the light having reached the second lateral side back along the light guide plate, wherein a rear surface of the light guide plate includes a stepped unevenness having first surfaces configured to reflect light toward the liquid crystal panel and second surfaces configured to reflect light toward the mirror, and wherein a thickness of the light guide plate increases in a first direction from the first lateral side to the second lateral side such that the second lateral side of the light guide plate is thicker than the first lateral side of the light guide plate.

2 . The display device of claim 1 , wherein the first surfaces have a first angle and the second surfaces correspondingly adjacent to the first surfaces have a second angle different than the first angle, and
wherein the first and second surfaces are formed in a curved band concaving toward the first lateral side in a top view of the light guide plate.

3 . The display device of claim 1 , wherein the mirror includes a plurality of inclined surfaces having an inclined angle in bilateral symmetry in a second direction vertical to the first direction.

4 . The display device of claim 3 , wherein the mirror is formed in a Fresnel shape with a same distance from a first LED arranged in a center of the first lateral side of the light guide plate to the mirror.

5 . The display device of claim 2 , wherein the first surfaces inclined at the first angle and the second surfaces inclined at the second angle are alternatively arranged in the stepped unevenness formed in the rear surface of the light guide plate.

6 . The display device of claim 1 , further comprising:
a reflector disposed behind the light guide plate and configured to reflect light passing through the light guide plate back through the light guide plate.

7 . The display device of claim 6 , wherein the reflector includes a plurality of inclined surfaces inclined toward the mirror.

8 . The display device of claim 7 , wherein the light having reached the inclined surfaces of the reflector is incident on the rear surface of the light guide plate at an angle smaller than a critical angle of the light guide plate and the light travels toward the liquid crystal panel after passing through the light guide plate.

9 . The display device of claim 7 , wherein the plurality of the inclined surfaces are formed in a band shape concavely curved toward the first lateral side of the light guide plate.

10 . The display device of claim 1 , further comprising:
a diffusion film disposed between the light guide plate and the liquid crystal panel.

11 . A mobile terminal comprising:
a case; a display device provided in a front surface of the case; and a wireless communication unit configured to provide wireless communication; and a controller configured to control a light source of a backlight unit of the display device, wherein the display device includes: a liquid crystal panel configured to selectively transmit light for each pixel of the liquid crystal panel; a light guide plate provided behind the liquid crystal panel; a light source array including a plurality of LEDs arranged in a row at a first lateral side of the light guide plate, and configured to emit light to the first lateral side of the light guide plate; and a mirror provided in a second lateral side of the light guide plate and configured to reflect the light having reached the second lateral side back along the light guide plate, wherein a rear surface of the light guide plate includes a stepped unevenness having first surfaces configured to reflect light toward the liquid crystal panel and second surfaces configured to reflect light toward the mirror, and wherein a thickness of the light guide plate increases in a first direction from the first lateral side to the second lateral side such that the second lateral side of the light guide plate is thicker than the first lateral side of the light guide plate.

12 . The mobile terminal of claim 11 , wherein the first surfaces have a first angle and the second surfaces correspondingly adjacent to the first surfaces have a second angle different than the first angle, and
wherein the first and second surfaces are formed in a curved band concaving toward the first lateral side in a top view of the light guide plate.

13 . The mobile terminal of claim 11 , wherein the mirror includes a plurality of inclined surfaces having an inclined angle in bilateral symmetry in a second direction vertical to the first direction.

14 . The mobile terminal of claim 13 , wherein the mirror is formed in a Fresnel shape with a same distance from a first LED arranged in a center of the first lateral side of the light guide plate to the mirror.

15 . The mobile terminal of claim 12 , wherein the first surfaces inclined at the first angle and the second surfaces inclined at the second angle are alternatively arranged in the stepped unevenness formed in the rear surface of the light guide plate.

16 . The mobile terminal of claim 11 , wherein the display unit further comprises:
a reflector disposed behind the light guide plate and configured to reflect light passing through the light guide plate back through the light guide plate.

17 . The mobile terminal of claim 16 , wherein the reflector includes a plurality of inclined surfaces inclined toward the mirror.

18 . The mobile terminal of claim 17 , wherein the light having reached the inclined surfaces of the reflector is incident on the rear surface of the light guide plate at an angle smaller than a critical angle of the light guide plate and the light travels toward the liquid crystal panel after passing through the light guide plate.

19 . The mobile terminal of claim 11 , wherein the light source array comprises:
a first LED arranged in a center of the portion of the light guide plate; and a second LED arranged on right and left sides of the first LED, and wherein the controller is further configured to: turn on only the first LED in a first mode; turn on the first LED and the second LED in a second mode; and turn on all of the LEDs arranged in the light source array in a third mode.

20 . The mobile terminal of claim 19 , wherein the first mode is a secret display mode in which an image is seen only when a view angle is in a preset range of angles,
wherein the second mode is a power save mode in which an image is seen dark when the view angle is out of the preset range of the angles, and wherein the third mode is a wide view mode in which an image is seen at the same brightness regardless of the view angle.

Assignees

• Lg Electronics Inc

Inventors

• Seen Seungmin
• Sohn Joonsung
• Kim Misook

Classifications

• G02B6/0055

  Reflecting element, sheet or layer · CPC title

• G02B6/0051

  Diffusing sheet or layer · CPC title

• G02B6/0046

  Tapered light guide, e.g. wedge-shaped light guide · CPC title

• G02B6/0068 Primary

  Arrangements of plural sources, e.g. multi-colour light sources · CPC title

• G02B6/0073

  Light emitting diode [LED] · CPC title