Illuminating device and display device including the same

• US 7,476,016 B2
• Filed: 05/24/2006
• Issued: 01/13/2009
• Est. Priority Date: 06/28/2005
• Status: Active Grant

• Current Assignee: Hickory IP LLC (IP Edge LLC)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Kurihara, Makoto
• Primary Examiner(s): Husar, Stephen F
• Application Number:
  US11/439,901
• Publication Number:
  US 20060289880A1
• Time in Patent Office: 965 Days
• Field of Search: 362/231, 362/251, 362/276, 362/295, 362/394, 362/555.561, 362/612, 362/613, 362/631
• US Class Current: 362/612
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• 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 2924/00014 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 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/40 Details of LED load circuits

Abstract

Provided is a display device including: a light guide member for mixing light from a blue LED element coated with a translucent resin mixed with phosphor particles which converts blue light into green light with light from a red LED element to make white light exit from a light exit surface; and a non-self light emission display element provided on an irradiating surface side of the light guide member. Therefore, the display element is irradiated with white light whose sufficient wavelength region is 600 nm or more and whose intensity efficiency is high. When the display device further includes a circuit for separately controlling light emission intensities of the red LED element and a blue LED element, chromatic balance can be adjusted even after manufacturing and an intensity of the display device and color reproducibility thereof can be easily set in an optimum range even after assembly.

Claims

1. A display device comprising:

a red light emitting diode package including a red LED element that emits a red light;

a blue LED element that emits a blue light;

phosphor particles for converting the blue light into a green light having a peak wavelength in a green spectral region;

a blue-green light emitting diode package including the blue LED element potted in a resin in which the phosphor particles are dispersed;

a display element of a non-self light emission type having a color filter, the display element being illuminated by the blue light, the green light and the red light; and

a circuit for controlling light emission intensities of the red LED element and the blue LED element so that the display device exhibits a preferable color balance.

2. A display device according to claim 1;

wherein the blue LED element is made of material of one of InGaN and GaN;

the red LED element is made of a material selected from the group consisting of GaP, GaAlAs, and AlGaInP; and

the phosphor particles are selected from the group consisting of at least one of SrGa₂S₄;

Eu, Ca₃Sc₂Si₃O₁₂;

Ce, and Sr-SION;

Eu.

3. A display device according to claim 2;

wherein the resin is a non-permeable material.

4. A display device according to claim 3;

wherein the non-permeable material comprises at least one selected from the group consisting of silicon resin, cycloolefin resin, fluorine resin, and epoxy resin.

5. A display device according to claim 1;

wherein the circuit comprises a driver circuit for the red LED element and a driver circuit for the blue LED element; and

the driver circuit for the red LED element includes a temperature-sensitive resistor.

6. A display device according to claim 1 wherein the circuit comprises a driver circuit for the red LED element and a driver circuit for the blue LED element;

and the driver circuit for the blue LED element includes a current detecting resistor.

7. An illumination device comprising:

a blue LED element that emits a blue light;

phosphor particles for converting the blue light into a green light having a peak wavelength in a green spectral region;

a blue-green light emitting diode package including the blue LED element potted in a resin in which the phosphor particles are dispersed;

a red light emitting diode package including a red LED element that emits a red light; and

a circuit for controlling light emission intensities of the red LED element and the blue LED element so that the illumination device provides illuminating light that has a preferable color balance.

8. An illumination device according to claim 7;

wherein the blue LED element is made of a material of one of InGaN and GaN.

9. An illumination device according to claim 7;

wherein the phosphor particles are selected from the group consisting of at least one of SrGa₂S₄;

Eu, Ca₃Sc₂Si₃O₁₂;

Ce, and Sr-SION;

Eu.

10. An illumination device according to claim 7;

wherein the red LED element is made of a material selected from the group consisting of GaP, GaAlAs, and AlGaInP.

11. An illumination device according to claim 7;

wherein the resin comprises a non-permeable material.

12. An illumination device according to claim 7;

wherein the non-permeable material comprises at least one selected from the group consisting of silicon resin, cycloolefin resin, fluorine resin, and epoxy resin.

13. An illumination device according to claim 7;

wherein the circuit comprises a driver circuit for the red LED element and a driver circuit for the blue LED element; and

the driver circuit for the red LED element includes a temperature-sensitive resistor.

14. An illumination device according to claim 7;

wherein the circuit comprises a driver circuit for the red LED element and a driver circuit for the blue LED element; and

the driver circuit for the blue LED element includes a current detecting resistor.

15. An illumination device comprising:

a red light-emitting diode package having a red LED element that emits red light;

a blue-green light-emitting diode package having a blue LED element that emits blue light and that is encapsulated in a resin in which are dispersed particles that transform the blue light into green light having a peak wavelength in a green spectral region;

a light guide member that receives and mixes the red light, the blue light and the green light to obtain white light which exits from a light exit surface of the light guide member as illuminating light; and

a circuit that controls the light emission intensities of the packaged red LED element and the packaged blue LED element to thereby control the color balance of the illuminating light.

16. An illuminating device according to claim 15;

wherein the circuit comprises a driver circuit that drives the red LED element and that includes a temperature-sensitive resistor, and a drive circuit that drives the blue LED element.

17. An illuminating device according to claim 16;

wherein the driver circuit that drives the blue LED element includes a current detecting resistor.

18. An illuminating device according to claim 15;

wherein the circuit comprises a driver circuit that drives the red LED element, and a driver circuit that drives the blue LED element and that includes a current detecting resistor.

19. An illuminating device according to claim 15;

wherein the circuit includes a current detecting element that detects the current flowing through the blue LED element and controls the current flowing through the red LED element based on the detected current value.

20. An illuminating device according to claim 15;

wherein the circuit includes means for selectively adjusting the current value ratio of the current flowing through the blue LED element to the current flowing through the red LED element.