Illuminating device, electro-optical device, and electronic apparatus

• US 20050141065A1
• Filed: 12/21/2004
• Published: 06/30/2005
• Est. Priority Date: 12/22/2003
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Masamoto, Taketoshi
• Granted Patent: US 7,234,854 B2
• Time in Patent Office: Days
• US Class Current: 359/15
• 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 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0063 for extracting light out both the major surfaces of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

An illuminating device is provided for use as a backlight of a liquid crystal display, and has a plurality of light sources and a light guiding plate emitting lights from the light sources outward. At least one of the light sources is configured to be lighted independently from the rest of the light sources. This illuminating device is applied to equipment such as a two surface display type cellular phone and is disposed between a main panel and a sub-panel to illuminate both panels. All light sources may be used to illuminate the main panel when the main panel is used, and some of the light sources may be used to illuminate only an area of the sub-panel when the sub-panel is used so that effective illumination may be implemented. Accordingly, light sources need not to be unnecessarily lighted when the sub-panel is used, which leads to low power consumption.

Claims

1. An electro-optical device comprising:

an illuminating device including;

a light guiding plate;

a plurality of light sources that illuminate the light guiding plate with light; and

a control unit that controls at least one light source among the plurality of the light sources to illuminate independently from the rest of the light sources;

a first display panel disposed on one surface of the illuminating device; and

a second display panel disposed on the other surface of the illuminating device.

2. The electro-optical device according to claim 1, wherein the illuminating device has a control unit which controls all the light sources to illuminate in a first mode and fewer of the light sources to illuminate in a second mode than in the first mode.

3. The electro-optical device according to claim 1, wherein the illuminating device has a first mode and a second mode for illuminating an area smaller than that in the first mode, and lights a light source selected from the light sources to selectively illuminate a portion to be illuminated in the second mode.

4. The electro-optical device according to claim 1, wherein the illuminating device has a first mode and a second mode having a brightness lower than that in the first mode, and lights a light source selected from the light sources in the second mode.

5. The electro-optical device according to claim 2, wherein the light sources are disposed along one side of the light guiding plate, the illuminating device also has an auxiliary light source disposed at a side opposing the one side of the light guiding plate, and the control unit lights the at least one light source and the auxiliary light source in the second mode.

6. The electro-optical device according to claim 2, wherein the light sources are disposed along one side of the light guiding plate, the illuminating device also has an auxiliary light source disposed at a side opposing the one side of the light guiding plate, and the control unit further has a third mode for lighting the at least one light source and the auxiliary light source.

7. The electro-optical device according to claim 2,

wherein a display area of the second display panel is smaller than that of the first display panel.

8. The electro-optical device according to claim 7,

wherein the control unit performs lighting control in the first mode when the first display panel is illuminated, and performs lighting control in the second mode when the second display panel is illuminated.

9. The electro-optical device according to claim 1, further comprising:

a transflective sheet disposed between the illuminating device and the second display panel,

wherein the transflective sheet reflects a portion of light components emitted from the illuminating device toward the first display panel while transmitting the rest of the light components toward the second display panel.

10. The electro-optical device according to claim 2, wherein the control unit controls an amount of electric current supplied to the selected light source in the second mode to be different from that in each of the light sources in the first mode.

11. The electro-optical device according to claim 10, wherein the control unit controls an amount of electric current supplied in the second mode to be larger than that in the first mode.

12. The electro-optical device according to claim 11,

wherein the control unit determines an amount of electric current in each mode based on the brightness of the illuminating device in each of the first and second modes and the panel transmittance of the display panel illuminated by the illuminating device in each mode.

16. An electronic apparatus comprising:

an electro-optical device according to claim 1 in a display unit,

wherein a first display panel is mounted on one surface of the display unit and a second display panel is mounted on the other surface of the display unit.

13. An illuminating device used for an electro-optical device, comprising:

a light guiding plate;

a plurality of light sources that illuminate the light guiding plate with light; and

a control unit that controls all the light sources to illuminate in a first mode and fewer of the light sources to illuminate in a second mode than in the first mode.

14. The illuminating device according to claim 13,

wherein the illuminating device has a first mode and a second mode for illuminating an area smaller than that in the first mode, and lights a light source selected from the light sources to selectively illuminate a portion to be illuminated in the second mode.

15. The illuminating device according to claim 13,

wherein the illuminating device has a first mode and a second mode having a brightness lower than that in the first mode, and lights a light source selected from the light sources in the second mode.