Optical device, light source device, and projector

1. An optical device comprising:

a light-emitting layer structure constituted of a first light-emitting layer and a second light-emitting layer; and a wavelength selection unit, wherein

the wavelength selection unit is disposed on one side of the light-emitting layer structure,

the first light-emitting layer emits light having a first wavelength region,

the second light-emitting layer emits light having a second wavelength region based on light emitted from the first light-emitting layer, and

the wavelength selection unit allows a part of light having the first wavelength region emitted from the light-emitting layer structure to pass through, returns the remaining light to the light-emitting layer structure, and allows light having the second wavelength region to pass through.

2. The optical device according to claim 1 , wherein

the wavelength selection unit allows light in a first wavelength band and a second wavelength band to pass through, out of the first wavelength region from the light-emitting layer structure, and

the second wavelength region and the second wavelength band at least partially overlap.

3. The optical device according to claim 1 , wherein

the second light-emitting layer further emits light having the second wavelength region based on the remaining light in the first wavelength region returned to the light-emitting layer structure by the wavelength selection unit.

4. The optical device according to claim 1 , wherein

the first light-emitting layer does not absorb the remaining light in the first wavelength region returned to the light-emitting layer structure by the wavelength selection unit.

5. The optical device according to claim 1 , wherein

a lens system is disposed between one side of the light-emitting layer structure and the wavelength selection unit, and

light that passes through the lens system and propagates to the wavelength selection unit is converted into collimated light by the lens system.

6. The optical device according to claim 1 , wherein

the first light-emitting layer emits light having the first wavelength region based on energy supplied from an energy generation unit.

7. The optical device according to claim 6 , wherein

the energy generation unit is constituted of a light-emitting element.

8. The optical device according to claim 7 , wherein

the energy supplied from the energy generation unit to the first light-emitting layer is light having a third wavelength region.

9. The optical device according to claim 8 , wherein

a light reflection unit is disposed on another side of the light-emitting layer structure, and

light from the energy generation unit enters the light-emitting layer structure from the one side of the light-emitting layer structure.

10. The optical device according to claim 9 , further comprising

a light transmission/reflection unit, wherein

light from the energy generation unit is reflected by the light transmission/reflection unit, passes through the wavelength selection unit, and enters the light-emitting layer structure, and

light emitted from the light-emitting layer structure and passed through the wavelength selection unit passes through the light transmission/reflection unit.

11. The optical device according to claim 10 , further comprising:

a phase difference plate that controls light from the energy generation unit to be a first polarization state and a second polarization state; and a second light reflection unit, wherein

the phase difference plate is disposed between the energy generation unit and the light transmission/reflection unit, and

in the first polarization state, light which passed through the phase difference plate and entered the wavelength selection unit is reflected by the light transmission/reflection unit, passes through the wavelength selection unit, and enters the light-emitting layer structure, and in the second polarization state, light passes through the light transmission/reflection unit, is reflected by the second light reflection unit, reenters the light transmission/reflection unit, and is reflected by the light transmission/reflection unit.

12. The optical device according to claim 10 , wherein

a phase difference plate is disposed between the light transmission/reflection unit and the wavelength selection unit,

a second light transmission/reflection unit is disposed between the phase difference plate and the wavelength selection unit,

light which was reflected by the light transmission/reflection unit and passed through the phase difference plate is partially reflected by the second light transmission/reflection unit, reenters the phase difference plate, and passes through the phase difference plate and the light transmission/reflection unit, and

light which passed through the phase difference plate and the second light transmission/reflection unit passes through the wavelength selection unit and enters the light-emitting layer structure.

13. The optical device according to claim 8 , wherein

a light transmission/reflection unit is disposed on another side of the light-emitting layer structure,

light from the energy generation unit passes through the light transmission/reflection unit and enters the light-emitting layer structure from another side of the light-emitting layer structure, and

light emitted from the light-emitting layer structure is reflected by the light transmission/reflection unit.

14. A light source device comprising:

an optical device which includes a light-emitting layer structure constituted of a first light-emitting layer and a second light-emitting layer, and a wavelength selection unit; and

an energy generation unit, wherein

the wavelength selection unit is disposed on one side of the light-emitting layer structure,

the first light-emitting layer emits light having a first wavelength region,

the second light-emitting layer emits light having a second wavelength region based on light emitted from the first light-emitting layer, and

the wavelength selection unit allows a part of light having the first wavelength region emitted from the light-emitting layer structure to pass through, returns the remaining light to the light-emitting layer structure, and allows light having the second wavelength region to pass through.

15. A projector comprising:

a light source device equipped with an optical device which includes a light-emitting layer structure constituted of a first light-emitting layer and a second light-emitting layer and a wavelength selection unit, and an energy generation unit;

an illumination optical system;

an image forming unit; and

a projection optical system, wherein

the wavelength selection unit is disposed on one side of the light-emitting layer structure,

the first light-emitting layer emits light having a first wavelength region,

the second light-emitting layer emits light having a second wavelength region based on light emitted from the first light-emitting layer,

the wavelength selection unit allows a part of the light having the first wavelength region emitted from the light-emitting layer structure to pass through, returns the remaining light to the light-emitting layer structure, and allows light having the second wavelength region to pass through,

an image is formed by the image forming unit using light passed through the wavelength selection unit, and

the image formed by the image forming unit is sent to the projection optical system.