Lighting device and display device provided with the same

• US 7,821,188 B2
• Filed: 01/30/2008
• Issued: 10/26/2010
• Est. Priority Date: 01/31/2007
• Status: Expired due to Fees

• Current Assignee: Dawncrest IP LLC (IP Edge LLC)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Kurihara, Makoto, Ono, Masashi
• Primary Examiner(s): Patel, Ashok
• Application Number:
  US12/011,974
• Publication Number:
  US 20080231162A1
• Time in Patent Office: 1,000 Days
• Field of Search: None
• US Class Current: 313/484
• CPC Class Codes: F21V 14/08 by movement of the screens or filters
• CPC Class Codes: F21V 9/32 characterised by the arrangement of the photoluminescent material
• CPC Class Codes: F21V 9/38 Combination of two or more photoluminescent elements of different materials
• CPC Class Codes: F21V 9/45 by adjustment of photoluminescent elements
• CPC Class Codes: F21W 2131/406 for theatres, stages or film studios
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/133624 characterised by their spectral emissions
• CPC Class Codes: G02F 2203/62 Switchable arrangements whereby the element being usually not switchable

Abstract

To provide a lighting device capable of a substantial color adjustment and unlimited control of spectral components, a lighting device of the present invention puts a first transparent plate in which a phosphor layer dispersed with a first phosphor is formed in places and a second transparent plate in which a phosphor layer dispersed with a second phosphor is formed in places in a path of light from a light source, and stacks the first transparent plate and the second transparent plate on top of each other. The second phosphor differs from the first phosphor. How much in terms of area the phosphor layers overlap with each other is made variable, and the color tone of the lighting device can thus be controlled. The lighting device uses a blue light source as its light source, a green phosphor as the first phosphor, and a red phosphor as the second phosphor. An intended chromaticity can be obtained by varying how much in terms of area the green phosphor layer and the red phosphor layer overlap with each other and thereby adjusting the green light absorption amount of the red phosphor.

Claims

1. A lighting device, comprising:

a first member having a region where a first phosphor is present and a region where the first phosphor is absent; and

a second member having a region where a second phosphor is present and a region where the second phosphor is absent,

wherein the first member and the second member are put in a path of light emitted by a light emitting element, and are arranged in a manner that allows the region where the first phosphor is present and the region where the second phosphor is present to overlap with each other in a varying amount which is measured by area.

2. A lighting device according to claim 1, wherein the region where the first phosphor is present is shaped like a matrix in which rectangular unit regions are arranged into a matrix pattern.

3. A lighting device according to claim 2, wherein longer sides of the rectangular unit regions are set parallel to a moving direction of the second member.

4. A lighting device according to claim 2, wherein the rectangular unit regions are in contact with adjacent unit regions.

5. A lighting device according to claim 1, wherein the first member and the second member are circular members, and the first phosphor and the second phosphor are put in some places of the circular members.

6. A lighting device according to claim 5,

wherein the circular members are partially rotated, and

wherein light emission by the light emitting element is timed with a change in how much in terms of area the region where the first phosphor is present and the region where the second phosphor is present overlap with each other.

7. A lighting device according to claim 1, further comprising a third member in which a color filter layer is formed in places and which is placed nearer to a light exit side than the first member and the second member.

8. A lighting device according to claim 1, wherein the first phosphor is a green phosphor and the second phosphor is a red phosphor.

9. A lighting device according to claim 8, wherein the green phosphor contains at least one of strontium thiogallate activated with a rare earth element, barium strontium silicate activated with a rare earth element, and Ca₃Sc₂Si₃O₁₂:

Ce.

10. A lighting device according to claim 8, wherein the red phosphor contains at least one of phosphors that are obtained by doping each of CaS, SrS, (Ca, Sr)₂Si₅N₈, CaSiN₂, and CaAlSiN₃O₁₂ with a rare earth dopant.

11. A display comprising:

a lighting device; and

a non-self-luminous display element provided on an irradiating surface side of the lighting device,

wherein the lighting device places a first member having a region where a first phosphor is present and a region where the first phosphor is absent and a second member having a region where a second phosphor is present and a region where the second phosphor is absent in a path of light emitted by a light emitting element, and

wherein the first member and the second member are arranged in a manner that allows the region where the first phosphor is present and the region where the second phosphor is present to overlap with each other in a varying amount which is measured by area.