Light-emitting device and manufacturing method thereof

• US 20030230751A1
• Filed: 04/03/2003
• Published: 12/18/2003
• Est. Priority Date: 05/31/2002
• Status: Active Grant

• Current Assignee: Stanley Electric Company Limited
• Original Assignee: Stanley Electric Company Limited
• Inventors: Harada, Mitsunori
• Granted Patent: US 6,809,342 B2
• Time in Patent Office: Days
• US Class Current: 257/80
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

In the light-emitting device provided with the conventional wavelength converter, colors became irregular, and light radiated to a side of the semiconductor light-emitting element from the wavelength converter could not be used as radiation light, thus lowered the conversion efficiency. The present invention improves the availability of the light from the wavelength converter 5 and resolves the problems by realizing a composition of an LED lamp, wherein a light-radiation-direction-limiter 4a and reflector 4b around it are mounted on a substrate 4, a wavelength converter 5 is mounted on a proper position to cover a part of the light-radiation-direction-limiter 4a and the reflector 4b, and among the light whose wavelength gets converted from fundamental wavelength-light into wavelength-converted light at the wavelength converter 5, both the wavelength-converted light transmitted through the aforementioned wavelength converter 5 and radiated to the front face as direct light, and the wavelength-converted light radiated to the inner face of the wavelength converter 5, by reflecting towards the radiation direction of this light-emitting 1 by the reflector 4b, can be taken out as output light.

Claims

1. A light-emitting device, comprising a substrate, a semiconductor light-emitting element mounted on the substrate, and a wavelength converter for absorbing a fundamental wavelength-light radiated from the semiconductor light-emitting element and converting it into a wavelength-converted light having a wavelength longer than the same, characterizing in being composed to allow the front-transmitted-wavelength-converted light transmitted to the front of said wavelength converter, back-reflected-wavelength-converted light converted in wavelength in said wavelength converter and reflected to the back, and back-reflected-fundamental-wavelength light not converted in wavelength in said wavelength converter and reflected to the back, among lights having attained said wavelength converter.

2. The light-emitting device of claim 1, comprising a light irradiation direction limiter for irradiating light from said semiconductor light-emitting element arranged with a proper interval on said wavelength converter by converging it into said wavelength converter, and a light reflector for reflecting said back-reflected-wavelength-converted light and said back-reflected-fundamental-wavelength light in the radiation direction of said light-emitting device.

12. The light-emitting device of any of claims 1 to 11, wherein:

an optical thin film for reflecting selectively ultraviolet light is formed on a transparent aperture plate member for sealing the interior of said substrate.

13. The light-emitting device of any of claims 1 to 11, wherein:

said wavelength converter directs a face to a main irradiation axis of said light-emitting device to said semiconductor light-emitting element at an angle.

14. A manufacturing method of the light-emitting device of any of claims 1 to 11, comprising steps of:

forming a substrate;

obtaining an electrical contact between an electrode and a semiconductor light-emitting element;

sealing an interior of the substrate with a transparent seal member; and

forming a wavelength converter.

15. The manufacturing method of the light-emitting device of claim 12, wherein:

the step of forming said wavelength converter includes a step of forming a phosphor layer of a predetermined thickness by potting or silk-screen printing of a resin containing phosphor on a transparent aperture plate.

16. The manufacturing method of the light-emitting device of claim 12, wherein:

the step of forming said wavelength converter is a step of forming it on the transparent seal member for sealing the interior of the substrate in the transparent seal member.

17. The manufacturing method of the light-emitting device of claim 12, comprising a step of forming a reflective coating on said inner wall of said reflector and/or a light-radiation-direction-limiter.

18. The manufacturing method of the light-emitting device of claim 12, comprising a step of forming a second wavelength converter in said reflector.

3. A light-emitting device, comprising a substrate, a semiconductor light-emitting element mounted on the substrate and a wavelength converter by a phosphor for releasing a wavelength-converted light having a wavelength different from the fundamental wavelength-light radiated from said semiconductor light-emitting element, wherein:

said substrate is provided with a light-radiation-direction-limiter in the shape of a horn having an inner wall open upward on a substantially central portion having a function to limit the light-radiation-direction from said semiconductor light-emitting element and a reflector around said light-radiation-direction-limiter, said wavelength converter is arranged to cover an opening of said light-radiation-direction-limiter and not to come into contact with a limiter edge, and both of wavelength-converted light transmitted through said wavelength converter and radiated in the irradiation direction of said light-emitting element, fundamental-wavelength light reflected to the inner face of said wavelength converter, among lights having attained said wavelength converter, and/or light reflecting wavelength-converted light to the radiation direction of said light-emitting by said reflector can be taken out as output light.

4. The light-emitting device of claim 3, wherein:

said wavelength converter is provided with an interval not more than 10 mm from a surface of said semiconductor light-emitting element disposed at a bottom face of the light-radiation-direction-limiter arranged substantially at the central portion of said substrate, and at the same time, disposed to cover said light-radiation-direction-limiter.

5. The light-emitting device of claim 3 or 4, wherein:

a reflection film coated with material comprising one or more of aluminum, silver, barium sulfate and magnesium oxide is formed on said inner wall of said light-radiation-direction-limiter.

6. The light-emitting device of any of claim 3 to 5, wherein:

said inner wall of said light irradiation direction limiter is open in a range of 10 to 45 in respect to the main irradiation axis of said light-emitting device.

7. The light-emitting device of any of claims 3 to 6, wherein:

a reflection film coated with material comprising one or more of aluminum, silver, barium sulfate and magnesium oxide on a surface thereof is formed on said reflector.

8. The light-emitting device of any of claims 3 to 6, wherein:

said reflector has its surface coated with the wavelength converter.

9. The light-emitting device of any of claims 3 to 8, wherein:

said wavelength converter is a fluorescent agent activated by the light radiated from said semiconductor light-emitting element to emit light.

10. The light-emitting device of any of claims 3 to 9, wherein:

said wavelength converter installed in from of said semiconductor light-emitting element is formed in a ratio of 25 to 75% of the opening area composed by said light-radiation-direction-limiter and reflector arranged on said substrate.

11. The light-emitting device of any of claims 3 to 10, wherein:

said semiconductor light-emitting element is a compound 30 semiconductor radiating light of 370 nm to 420 nm in light-emitting wavelength.