Wavelength conversion element, wavelength conversion system, light source apparatus, and projector
A wavelength conversion element includes a phosphor layer that emits fluorescence when excitation light is incident on the phosphor layer, a base having a reflection layer, and a filter provided on a side of the phosphor layer that is the side opposite the reflection layer. The filter is so configured that the reflectance of light that belongs to a wavelength region from the wavelength of the excitation light to the wavelength of the fluorescence and is incident on the filter at right angles is minimized at a first wavelength, and the first wavelength is located between the peak wavelength of the excitation light and the peak wavelength of the fluorescence.
1. A wavelength conversion element comprising:
a phosphor layer that emits fluorescence when excitation light is incident on the phosphor layer;
a base having a reflection layer; and
a filter provided on a side of the phosphor layer that is a side opposite the reflection layer,
wherein the filter is so configured that reflectance of light that belongs to a wavelength region from a wavelength of the excitation light to a wavelength of the fluorescence and is incident on the filter at a zero-degree incident angle is minimized at a first wavelength, and, while the reflectance is minimized at the first wavelength, the reflectance is larger than the minimized reflectance at a second wavelength that is smaller than the first wavelength and at a third wavelength that is larger than the first wavelength, and
the first wavelength is located between a peak wavelength of the excitation light and a peak wavelength of the fluorescence.
2. A wavelength conversion element according to claim 1 ,
wherein the filter is so configured that the reflectance of light that belongs to the wavelength region and is incident at a first angle of incidence is minimized at the peak wavelength of the excitation light.
3. A wavelength conversion system comprising:
the wavelength conversion element according to claim 2 ; and
a pickup system on which the fluorescence emitted from the wavelength conversion element is incident.
4. A light source apparatus comprising:
a light emitter that outputs excitation light; and
the wavelength conversion element according to claim 2 .
5. A projector comprising:
the light source apparatus according to claim 4 ;
a light modulator that modulates light outputted from the light source apparatus; and
a projection optical apparatus that projects the light modulated by the light modulator.
6. A wavelength conversion system comprising:
the wavelength conversion element according to claim 1 ; and
a pickup system on which the fluorescence emitted from the wavelength conversion element is incident.
7. A light source apparatus comprising:
a light emitter that outputs excitation light; and
the wavelength conversion element according to claim 1 .
8. A projector comprising:
the light source apparatus according to claim 7 ;
a light modulator that modulates light outputted from the light source apparatus; and
a projection optical apparatus that projects the light modulated by the light modulator.
9. A wavelength conversion element comprising:
a phosphor layer that emits fluorescence when excitation light is incident on the phosphor layer;
a base having a reflection layer; and
a filter provided on a side of the phosphor layer that is a side opposite the reflection layer,
wherein the filter transmits excitation light incident on the filter at right angles out of the excitation light and fluorescence incident on the filter at right angles out of the fluorescence and reflects fluorescence incident on the filter at a second angle of incidence out of the fluorescence in such a way that optical intensity of the reflected fluorescence is higher than optical intensity of transmitted fluorescence.
10. The wavelength conversion element according to claim 9 ,
wherein the fluorescence is light containing green light and highly visible red light, and
the filter reflects at least part of red light incident on the filter at right angles and less visible than the highly visible red light.
11. A wavelength conversion system comprising:
the wavelength conversion element according to claim 10 ; and
a pickup system on which the fluorescence emitted from the wavelength conversion element is incident.
12. A light source apparatus comprising:
a light emitter that outputs excitation light; and
the wavelength conversion element according to claim 10 .
13. A projector comprising:
the light source apparatus according to claim 12 ;
a light modulator that modulates light outputted from the light source apparatus; and
a projection optical apparatus that projects the light modulated by the light modulator.
14. A wavelength conversion system comprising:
the wavelength conversion element according to claim 9 ; and
a pickup system on which the fluorescence emitted from the wavelength conversion element is incident.
15. A light source apparatus comprising:
a light emitter that outputs excitation light; and
the wavelength conversion element according to claim 9 .
16. A projector comprising:
the light source apparatus according to claim 15 ;
a light modulator that modulates light outputted from the light source apparatus; and
a projection optical apparatus that projects the light modulated by the light modulator.
17. A wavelength conversion element comprising:
a phosphor layer that emits fluorescence when excitation light is incident on the phosphor layer;
a first filter provided on a side of the phosphor layer that is a side on which the excitation light is incident;
a second filter provided on a side of the phosphor layer that is a side opposite the first filter; and
a base on which the phosphor layer on which the first filter and the second filter are provided is provided and which transmits the fluorescence,
wherein the first filter transmits excitation light incident on the first filter at right angles out of the excitation light, reflects excitation light incident on the first filter at a third angle of incidence out of the excitation light in such a way that optical intensity of the reflected excitation light is higher than optical intensity of transmitted excitation light, and reflects fluorescence incident on the first filter at right angles out of the fluorescence, and
the second filter transmits fluorescence incident on the second filter at right angles out of the fluorescence, reflects the fluorescence incident on the second filter at a fourth angle of incidence in such a way that optical intensity of the reflected fluorescence is higher than optical intensity of transmitted fluorescence, and reflects excitation light incident on the second filter at right angles out of the excitation light.
18. A wavelength conversion system comprising:
the wavelength conversion element according to claim 17 ; and
a pickup system on which the fluorescence emitted from the wavelength conversion element is incident.
19. A light source apparatus comprising:
a light emitter that outputs excitation light; and
the wavelength conversion element according to claim 17 .
20. A projector comprising:
the light source apparatus according to claim 19 ;
a light modulator that modulates light outputted from the light source apparatus; and
a projection optical apparatus that projects the light modulated by the light modulator.