Illumination Device and Display Device Using Illumination Device

• US 20080002100A1
• Filed: 06/26/2007
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kaneko, Hiroki, Tanaka, Toshiaki, Akiba, Yutaka
• Application Number:
  US11/768,218
• Publication Number:
  US 20080002100A1
• Time in Patent Office: Days
• US Class Current: 349/65
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00011 Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H05K 3/202 using self-supporting metal foil pattern

Abstract

An illumination device includes trains of lead frames and a plurality of light-emitting diodes provided in series on the lead frames. The trains of the lead frames are juxtaposed, and the light-emitting diodes are sealed with a reflecting resin and a transparent resin over a substrate. Gaps are provided between the lead frames and the substrate. The illumination device is employed as a backlight source in a display device.

Claims

1. An illumination device including:

a substrate;

a plurality of lead frames provided on said substrate;

a plurality of light-emitting diodes connected in series by said plurality of lead frames; and

transparent resin blocks placed on said lead frames and sealing said light-emitting diodes,

in which gaps are provided between said lead frames and said substrate.

2. An illumination device according to claim 1, wherein a reflecting resin block is provided to surround each of said light-emitting diodes on said lead frames so that the transparent resin blocks are placed on each reflecting resin block thereby to seal said light-emitting diodes.

3. An illumination device according to claim 2, wherein each of said lead frames has clinched portions so that said each lead frame is partly not in contact with said substrate.

4. An illumination device according to claim 3, wherein said clinched portion of each lead frame has a rising part standing off from said substrate.

5. An illumination device according to claim 3, wherein said clinched portion is provided at a region where said lead frame is in contact with said reflecting resin block or with said transparent resin block.

6. An illumination device according to claim 2, wherein said substrate has recesses on one surface on which said lead frames are provided so that said gaps are formed between said substrate and said lead frames at said recesses.

7. An illumination device according to claim 2, wherein a silver layer is provided between each of said light-emitting diodes and its associated lead frame.

8. An illumination device according to claim 2, wherein an adhesive layer is provided on one surface of said substrate on which said lead frames are placed.

9. An illumination device according to claim 2, wherein at least those of said lead frames which are adjacent to each other have areas contacted to their associated reflecting resin blocks or to their associated transparent resin blocks at different positions from each other.

10. An illumination device according to claim 2, wherein at least those of said lead frames which are adjacent to each other are exposed from their associated reflecting resin blocks or from their associated transparent resin blocks at positions different from each other as viewed in a direction transverse to the series-connected light emitting diodes.

11. An illumination device according to claim 10, wherein said reflecting resin blocks or said transparent resin blocks have depressed portions or protruding portions in a plane parallel with said substrate, said lead frames being exposed from said depressed or protruding portions of said reflecting resin blocks or of said transparent resin blocks.

12. An illumination device according to claim 2, wherein said light-emitting diodes include those capable of emitting light in a red wavelength region, those capable of emitting light in a green wavelength region and those capable of emitting light in a blue wavelength region, and those emitting light of the same colors are connected in series through said respective lead frames.

13. An illumination device according to claim 11, wherein the number of the lead frames series-connecting light-emitting diodes capable of emitting light in a red wavelength region, that of the lead frames series-connecting light-emitting diodes capable of emitting light in a green wavelength region and that of the lead frames series-connecting light-emitting diodes capable of emitting light in a blue wavelength region are in a ratio of 1:

2;

1.

14. An illumination device according to claim 12, wherein two trains of lead frames series-connecting light-emitting diodes which emit light in a green wavelength retion are arranged to be adjacent to each other.

15. An illumination device according to claim 2, wherein said light-emitting diodes include those capable of emitting light in a blue wavelength region or in a purple wavelength region, and a fluorescent material is provided on said reflecting resin blocks, the fluorescent material being excitable with light in the blue wavelength region or in the purple wavelength region for emission of light.

16. A liquid crystal display device comprising:

a backlight source including at least one illumination device each having a substrate, a plurality of lead frames provided on said substrate, a plurality of light-emitting diodes connected in series by said plurality of lead frames, and transparent resin blocks placed on said lead frames and sealing said light-emitting diodes;

a liquid crystal display panel to be supplied with light from said backlight source; and

an assembly of optical elements arranged between said backlight source and said liquid crystal display panel for controlling uniformity and directivity of light from said backlight source, in which gaps are provided between said lead frames and said substrate.

17. A liquid crystal display device according to claim 16, wherein a reflecting resin block is provided to surround each of said light-emitting diodes on said lead frames so that said transparent resin blocks are placed one on each reflecting resin block thereby to seal said light-emitting diodes.

18. A liquid crystal display device according to claim 17, said backlight source includes said illumination device arranged on the side surface of said liquid crystal display panel and includes a light guiding plate for letting in light from said illumination device to said liquid crystal display panel.

19. A liquid crystal display device according to claim 16, wherein said backlight source has plural sets of an illumination device and a light guiding plate, said light guiding plate in each set letting in light from its associated illumination device to said liquid crystal display panel, said plural sets being arranged in rows and columns.