LIGHT SOURCE DEVICE

• US 20110050111A1
• Filed: 08/26/2010
• Published: 03/03/2011
• Est. Priority Date: 08/27/2009
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ohnishi, Mitsuhisa, Onozaki, Manabu, Yamada, Akihisa, Tanaka, Takayoshi, TANAKA, Hiroshi
• Granted Patent: US 8,497,638 B2
• Time in Patent Office: Days
• US Class Current: 315/185.R
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133612 Electrical details
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

A light source device which is used as the backlight device and does not generate sound is provided. One or more flat substrates each having a light emitting element on its surface side are supported by a chassis having a conductive flat plate surface so that back surfaces of the substrates are opposed to the flat plate surface. The substrate comprises first wiring conductive thin films on a surface side of an insulation substrate, and one or more second radiating or wiring conductive thin films on a back surface side of the insulation substrate. Two terminals of the light emitting element are connected to the two adjacent first conductive thin films. A potential of at least one of the second conductive thin films is fixed to have a constant potential difference or preferably fixed to the same potential with respect to that of the flat plate surface of the chassis.

Claims

1. A light source device comprising

one or more flat substrates each having a light emitting element on its surface side, the substrates being supported by a chassis having a conductive flat plate surface so that back surfaces of the substrates are opposed to the flat plate surface of the chassis, wherein

each of the substrates is provided with a plurality of first conductive thin films for wiring formed on a surface side of an insulation substrate, and one or more second conductive thin films for radiating or wiring formed on a back surface side of the insulation substrate,

two terminals of the light emitting element are connected to the two adjacent first conductive thin films, respectively and

a potential of at least one of the second conductive thin films is fixed to have a constant potential difference with respect to a potential of the flat plate surface of the chassis.

2. The light source device according to claim 1, wherein

the potential of at least one of the second conductive thin films is fixed to the same potential as the potential of the flat plate surface of the chassis.

3. The light source device according to claim 1, wherein

at last one of the second conductive thin films is a radiating conductive thin film, and not electrically connected to the terminals of the light emitting element.

4. The light source device according to claim 3, wherein

a potential of the radiating conductive thin film is fixed to the same potential as the potential of the flat plate surface of the chassis.

5. The light source device according to claim 1, wherein

the plurality of light emitting elements are mounted on the one or more substrates, and at least two of the plurality of light emitting elements are connected in series to form a series circuit, and

brightness of the plurality of light emitting elements of the series circuit is controlled by supplying a fixed potential from one side end of the series circuit and driving a current flowing in the series circuit from the other side end of the series circuit.

6. The light source device according to claim 1, comprising

a connection terminal at an end side of each of the substrates or in a vicinity of the end side, electrically connected to the first conductive thin film formed in the vicinity of the end side, and used to electrically connect to an external circuit or the other substrate, wherein

a series circuit is formed of the light emitting elements mounted on the plurality of substrates by connecting the connection terminal of the one substrate to the connection terminal of the other substrate to connect the plurality of substrates, and

brightness of the plurality of light emitting elements of the series circuit is controlled by supplying a fixed potential from one side end of the series circuit and driving a current flowing in the series circuit from the other side end of the series circuit.

7. The light source device according to claim 6, wherein

a potential of the second conductive thin films is fixed to have a predetermined potential difference with respect to the potential of the flat plate surface of the chassis in at least one of the plurality of substrates, provided with the light emitting element having a maximum potential fluctuation at a terminal of the light emitting element due to drive of the current flowing in the series circuit.

8. The light source device according to claim 5, wherein

the current flowing in the series circuit is driven by pulse width modulation.

9. The light source device according to claim 6, wherein

the current flowing in the series circuit is driven by pulse width modulation.

10. The light source device according to claim 1, wherein

the potential of at least one of the second conductive thin films is fixed to the same potential as the potential of the flat plate surface of the chassis, by a conductive member to mount the substrates on the chassis.

11. The light source device according to claim 1, wherein

the potential of at least one of the second conductive thin films is fixed to the same potential as the potential of the flat plate surface of the chassis by opening a part of an insulation film covering the second conductive thin films provided on the back surface side of the substrates, and bringing the second conductive thin film exposed from the opening part of the insulation film into contact with the flat plate surface of the chassis directly or through a conductive connection member.

12. The light source device according to claim 1, comprising

a second connection terminal provided at an end side of each of the substrates or in a vicinity of the end side, electrically connected to the second conductive thin films formed in the vicinity of the end side, and used to electrically connect to an external circuit or the other substrate, wherein

the potential of at least one of the second conductive thin films is fixed to the same potential as the potential of the flat plate surface of the chassis by electrically connecting the second connection terminal to the flat plate surface of the chassis.