Plain light source device

• US 5,195,822 A
• Filed: 04/24/1991
• Issued: 03/23/1993
• Est. Priority Date: 04/24/1990
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Oyama, Hisashi, Takahashi, Nobuyuki
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): LEE, Y MY QUACH
• Application Number:
  US07/690,578
• Time in Patent Office: 699 Days
• Field of Search: 362/296, 362/299, 362/307, 362/311, 362/341, 362/800, 362/29, 181/211, 181/289, 359/48, 359/49, 359/70, 359/83, 359/50, 313/493
• US Class Current: 362/296.04
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors

Abstract

In a plain light source device used for backlighting a light transmission type liquid crystal display, a reflector for reflecting the light from the light source toward the liquid crystal panel is provided which is formed from a conductive resin (plastic) consisting of a resinous (plastic) material with a metal fiber mixed therein. The thus formed reflector is an insulator at its surfaces and a conductor inside. A board on which the light source is supported is electrically and mechanically connected to the reflector for grounding. The reflector thereby serves as a shield against the noise generated by the light source. Further, a transparent conductive sheet is disposed on the front side (on the display panel side) of the light source. The conductive sheet is electrically connected to the board for grounding. As a result, the light source is surrounded by the reflector and the tranparent conductive sheet, both grounded, thus providing further reliable shielding.

Claims

1. A plain light source device comprising a light source disposed on a rear side of a display panel and a reflector for reflecting the light from the light source toward the display panel, the reflector being formed from a conductive resin to prevent noise generated by the light source from causing external interference, the conductive resin having a metal fiber mixed therein, a board for holding the light source, wherein the reflector is electrically connected to the board for grounding.

2. The plain light source device as set forth in claim 1, wherein the reflector surrounds the light source except for an open top which faces the display panel.

3. The plain light source device as set forth in claim 2, wherein the reflector has a white reflecting surface.

4. The plain light source device as set forth in claim 2, wherein a transparent conductive sheet is disposed on the rear side of the display panel facing side of the light source.

5. The plain light source device as set forth in claim 3, wherein the transparent conductive sheet is electrically connected to the board for grounding.

6. The plain light source device as set forth in claim 3, wherein the transparent conductive sheet is formed from a transparent film with a thin metal of ITO evaporated on a surface of the transparent film.

7. The plain light source device as set forth in claim 1, wherein the conductive resin is made from a resin and the metal fiber, and the resin and the metal fiber are combined to form a single, one-piece reflector such that an additional shielding member overlying the reflector is avoided.

8. A plain light source device comprising:

a light source disposed on a rear side of a display panel and a reflector for reflecting light from a light source toward a display panel, wherein, the reflector is made of a conductive resin to prevent noise generated by the light source from causing external interference, the conductive resin having a metal fiber mixed therein, two side-by-side tubes being provided as the light source, a board being provided on one side of the reflector for holding the two side-by-side tubes and the reflector being electrically connected to the board by a single screw, the reflector and board enclosing the two side-by-side tubes while tops of the two side-by-side tubes are exposed to the display panel.