LIGHT EMITTING DEVICE AND METHOD FOR MANUFACTURING SAME

• US 20110001156A1
• Filed: 06/30/2010
• Published: 01/06/2011
• Est. Priority Date: 07/01/2009
• Status: Active Grant

• Current Assignee: Heavy Duty Lighting LLC (Ni, Wang & Massand, PLLC)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Hata, Toshio, Uemura, Toyonori, Matsuda, Makoto
• Granted Patent: US 8,399,899 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• 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 2224/49113 the connectors connecting different bonding areas on the semiconductor or solid-state body to a common bonding area outside the body, e.g. converging wires
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/00012 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 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A light emitting device includes: a substrate; an LED chip provided on a main surface of the substrate; and a printed resistor element connected in parallel with the LED chip, the printed resistor element being provided in at least one of regions (i) on the main surface of the substrate, (ii) on a back surface of the substrate, and (iii) inside the substrate. According to the arrangement, it is possible to provide: a light emitting device which can emit light having preferable luminance without a reduction in optical output by suppressing light shielding and light absorption of light emitted from the LED toward the outside; and a method for manufacturing the light emitting device.

Claims

1. A light emitting device comprising:

a substrate;

a semiconductor light emitting element provided on a main surface of the substrate; and

a protective element connected in parallel with the semiconductor light emitting element,

the protective element being a printed resistor provided in at least one of regions (i) on the main surface of the substrate, (ii) on a back surface of the substrate, and (iii) inside the substrate.

2. The light emitting device as set forth in claim 1, wherein:

the semiconductor light emitting element is covered with a fluorescent material-containing resin layer or a transmissive resin layer, each provided on the main surface of the substrate, the fluorescent material-containing resin layer being made of a resin containing a fluorescent material, the transmissive resin layer being made of a transmissive resin; and

the protective element is provided on the main surface and outside the fluorescent material-containing resin layer or the transmissive resin layer.

3. The light emitting device as set forth in claim 2, wherein:

the fluorescent material-containing resin layer or the transmissive resin layer has a dome shape.

4. The light emitting device as set forth in claim 2, wherein:

the protective element is provided in a corner of the main surface of the substrate.

5. The semiconductor light emitting element as set forth in claim 1, wherein:

the semiconductor light emitting element is covered with, via a fluorescent material-containing resin layer made of a resin containing a fluorescent material, a transmissive resin layer made of a transmissive resin, the fluorescent material-containing resin layer and the transmissive resin layer being provided on the main surface of the substrate; and

the protective element is provided on the main surface of the substrate and outside the transmissive resin layer.

6. The light emitting device as set forth in claim 5, wherein:

the transmissive resin layer has a dome shape.

7. The light emitting device as set forth in claim 5, wherein:

the protective element is provided in a corner of the main surface of the substrate.

8. The light emitting device as set forth in claim 1, wherein:

the substrate is made of ceramics; and

a wiring pattern is provided on the substrate,

the wiring pattern including;

cathode and anode electrodes electrically connected to the semiconductor light emitting element; and

cathode and anode electrodes electrically connected to the protective element.

9. The light emitting device as set forth in claim 8, wherein:

a glass layer is provided on a part of the wiring pattern other than at least the cathode and anode electrodes electrically connected to the semiconductor light emitting element, the wiring pattern being provided on the main surface; and

the protective element is covered with the glass layer, in a case where the protective element is provided on the main surface of the substrate.

10. The light emitting device as set forth in claim 8, wherein:

the semiconductor light emitting element is provided between the cathode and anode electrodes electrically connected to the semiconductor light emitting element on the main surface of the substrate; and

the protective element is provided on the cathode and anode electrodes electrically connected to the protective element so as to bridge between the cathode and anode electrodes electrically connected to the protective element.

11. The light emitting device as set forth in claim 9, wherein:

the glass layer is made of at least one selected from the group consisting of a borosilicate glass, a silica glass, a soda-lime glass, an aluminoborosilicate glass, a zinc borosilicate glass, an aluminosilicate glass, and a phosphate glass.

12. The light emitting device as set forth in claim 9, wherein:

the glass layer has a reflectivity in a range of 70% to 80%.

13. The light emitting device as set forth in claim 11, wherein:

the glass layer contains at least one selected from the group consisting of;

an inorganic dye made from argil, a titanium oxide, a barium oxide, talc, a barium sulfate, an aluminum hydroxide, silica, mica, a calcium carbonate, a calcium sulfate, or clay; and

an organic dye made from polymer beads.

14. The light emitting device as set forth in claim 1, wherein:

the protective element is covered with a glass layer or a solder resist.

15. The light emitting device as set forth in claim 14, wherein:

either the glass layer or the solder resist is milky white in color.

16. The light emitting device as set forth in claim 1, wherein:

the protective element has a resistance in a range of 1MΩ

to 10 GΩ

.

17. The light emitting device as set forth in claim 1, wherein:

the protective element is partially provided on the main surface of the substrate.

18. The light emitting device as set forth in claim 1, wherein:

the protective element is provided on the back surface of the substrate.

19. The light emitting device as set forth in claim 1, wherein:

the semiconductor light emitting element is covered with a fluorescent material-containing resin layer or a transmissive resin layer, each provided on the main surface of the substrate, the fluorescent material-containing resin layer being made of a resin containing a fluorescent material, the transmissive resin layer being made of a transmissive resin;

a white resin ring member is provided around the semiconductor light emitting element so as to dam the fluorescent material-containing resin layer or the transmissive resin layer; and

the protective element is provided on the main surface of the substrate and below the white resin ring member.

20. A method for manufacturing a light emitting device, the light emitting device including:

a substrate;

a semiconductor light emitting element provided on a main surface of the substrate; and

a protective element connected in parallel with the semiconductor light emitting element,

said method comprising the step of;

providing a printed resistor, as the protective element, in at least one of regions (i) on the main surface of the substrate, (ii) on a back surface of the substrate, and (iii) inside the substrate.