Lighting device and display device provided with the same
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.
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 Ca 3 Sc 2 Si 3 O 12 :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) 2 Si 5 N 8 , CaSiN 2 , and CaAlSiN 3 O 12 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.