Liquid crystal display device backlit by LED's coupled to printed circuit board

• US 5,453,855 A
• Filed: 12/09/1993
• Issued: 09/26/1995
• Est. Priority Date: 12/15/1992
• Status: Expired due to Fees

• Current Assignee: Koito Manufacturing Company Limited
• Original Assignee: Koito Manufacturing Company Limited
• Inventors: Nakamura, Yasuo, Furuya, Etsuo
• Primary Examiner(s): Gross, Anita Pellman
• Assistant Examiner(s): Abraham, Fetsum
• Application Number:
  US08/164,373
• Time in Patent Office: 656 Days
• Field of Search: 359/42, 359/48, 359/49, 359/83, 362/31, 362/26, 362/800
• US Class Current: 349/58
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133608 including particular frames or supporting means
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/133626 providing two modes of illumination, e.g. day-night
• CPC Class Codes: G09F 2013/1827 Prismatic window
• CPC Class Codes: G09F 2013/1831 using more than one light source

Abstract

A liquid crystal display device with an illuminator installed in the back of a liquid crystal display panel. The illuminator is made of a shallow box-form holder having a reflective inner surface, a plurality of LED'"'"'s installed in at least one side wall of the holder, a light-diffusing plate installed between the liquid crystal display panel and the holder, and a printed circuit board mounted on the outer surface of the bottom of the holder. The LED'"'"'s are of different light directional angles and inclined toward the bottom surface of the holder so that the light from the LED'"'"'s can be reflected by the reflective bottom surface towards the display panel.

Claims

1. A liquid crystal display device comprising a holder with a front surface thereof open, a liquid crystal display panel installed in said front-surface opening of said holder with a light-diffusing plate interposed between said holder and said display panel, a printed circuit board, and a plurality of LED'"'"'s coupled to said printed circuit board so as to back-illuminate said liquid crystal display panel from behind said light-diffusing plate, said holder further comprising:

holding parts for holding said LED'"'"'s;

a reflective surface formed on an inside bottom surface of said holder; and

wherein said light-diffusing plate is back-illuminated by a direct light emitted from said LED'"'"'s and a light reflected by said reflective surface, and said LED'"'"'s are at least two types of LED'"'"'s having different light directional angles.

2. A liquid crystal display device according to claim 1, wherein said LED'"'"'s are at least two types of LED'"'"'s which emit different colors of light.

3. A liquid crystal display device according to claim 2, wherein said holding parts which hold said LED'"'"'s includes a plurality of through-holes which are formed through at least one side wall of said holder so that respective axial lines of said through-holes are inclined toward said light-diffusing plate or toward said reflective surface.

4. A liquid crystal display device according to claim 2, wherein a hill-shaped raised portion which has said reflective surface is provided in a center of said inside bottom surface of said holder.

5. A liquid crystal display device according to claim 1, wherein said holding parts which hold said LED'"'"'s include a plurality of through-holes which are formed through at least one side wall of said holder so that respective axial lines of said through-holes are inclined toward said light-diffusing plate or toward said reflective surface.

6. A liquid crystal display device according to claim 5, wherein a hill-shaped raised portion which has said reflective surface is provided in a center of said inside bottom surface of said holder.

7. A liquid crystal display device according to claim 1, wherein a hill-shaped raised portion which has said reflective surface is provided in a center of said inside bottom surface of said holder.

8. A liquid crystal display device comprising a holder with a front-surface thereof open, a liquid crystal display panel installed in said front-surface opening of said holder with a light-diffusing plate interposed between said holder and said display panel, a printed circuit board, a plurality of LED'"'"'s coupled to said printed circuit board so as to back illuminate said liquid crystal display panel from behind said light-diffusing plate, said holder further comprising:

holding parts for holding said LED'"'"'s;

a reflective surface formed on an inside bottom surface of said holder;

a hill-shaped raised portion which has said reflective surface provided at a center of said inside bottom surface of said holder; and

wherein said-light-diffusing plate is back illuminated by a direct light emitted from said LED'"'"'s and a light reflective by said reflected surface, and said LED'"'"'s are at least two types of LED'"'"'s which emit different colors of light.

9. A liquid crystal display device comprising a holder with a front-surface thereof open, a liquid crystal display panel installed in said front-surface opening of said holder with a light-diffusing plate interposed between said holder and said display panel, a printed circuit board, a plurality of LED'"'"'s coupled to said printed circuit board so as to back illuminate said liquid crystal display panel from behind said light diffusing plate, said holder further comprising:

holder parts for holding said LED'"'"'s;

a reflective surface formed on an inside bottom surface of said holder;

a hill-shaped raised portion which has said reflective surfaces provided in a center of said inside bottom surface of said holder; and

wherein said light-diffusing plate is back illuminated by a direct light emitted from said LED'"'"'s and a light reflected by said reflective surface, and said holder parts which hold said LED'"'"'s include a plurality of through holes which are formed at least in one side wall of said holder so that respective axial lines of said through holes are inclined toward said light-diffusing plate or toward said reflective surface.

10. A liquid crystal display device comprising a holder with a front surface thereof open, a liquid crystal display panel installed in said front-surface opening of said holder with a light-diffusing plate interposed between said holder and said display panel, a printed circuit board, a plurality of LED'"'"'s coupled to said printed circuit board so as to back illuminate said liquid crystal display panel from behind said light diffusing plate, said holder further comprising:

holder parts for holding said LED'"'"'s;

a reflective surface formed on an inside bottom surface of said holder;

a hill-shaped raised portion which has said reflective surfaces provided in a center of said inside bottom surface of said holder; and

wherein said light-diffusing plate is back illuminated by a direct light emitted from said LED'"'"'s and a light reflected by said reflective surface.