Projection image display device
View Patent ↗A projection image display device of the present disclosure includes a light source, an image forming element that forms an image, a color separating and combining unit that separates first illumination light and second illumination light, and combines first projection light and second projection light reflected by the image forming element, and a notch filter that is disposed between the light source and the color separating and combining unit. A first dichroic filter reflects the first illumination light and the first projection light. A first incident angle of the first illumination light with respect to the first dichroic filter is different from a second incident angle of the first projection light with respect to the first dichroic filter. The notch filter attenuates light in a first wavelength band including a boundary between a wavelength band of the first illumination light and a wavelength band of the second illumination light.
1. A projection image display device, comprising:
a light source that illuminates light;
a light intensity distribution uniformizing unit that is disposed at a position where the light emitted from the light source is incident;
an image forming element that includes a first image forming element that forms a first image, and a second image forming element that forms a second image;
a color separating and combining unit that includes a first dichroic filter that separates the light from the light source into first illumination light and second illumination light having a wavelength band different from a wavelength band of the first illumination light, the color separating and combining unit emitting the first illumination light to the first image forming element, emitting the second illumination light to the second image forming element, and combining first projection light reflected by the first image forming element and second projection light reflected by the second image forming element; and
a notch filter that is disposed between the light intensity distribution uniformizing unit and the color separating and combining unit, wherein
the first dichroic filter reflects the first illumination light and the first projection light,
a first incident angle of the first illumination light with respect to the first dichroic filter is different from a second incident angle of the first projection light with respect to the first dichroic filter, and
the notch filter attenuates light in a first wavelength band including a boundary between the wavelength band of the first illumination light and the wavelength band of the second illumination light.
2. The projection image display device according to claim 1 , wherein
the wavelength band of the first illumination light is a red wavelength band, and
the wavelength band of the second illumination light is a green wavelength band.
3. The projection image display device according to claim 2 , wherein
the color separating and combining unit further includes
a first prism that faces the first image forming element, and
a second prism that faces the second image forming element, wherein the first dichroic filter is disposed between the first prism and the second prism.
4. The projection image display device according to claim 1 , wherein
when λ DM1 is smaller than λ DM2 , the notch filter satisfies λ DM3 >λ NF2 and λ DM1 +λ DM3 /4≤λ NF1 ≤λ DM2 −λ DM3 /4,
when λ DM1 is larger than λ DM2 , the notch filter satisfies λ DM3 >λ NF2 and λ DM2 +λ DM3 /4≤λ NF1 ≤λ DM1 −λ DM3 /4,
λ DM1 is a wavelength at which a transmittance of the first dichroic filter with respect to light incident on the first dichroic filter at the first incident angle is 50%,
λ DM2 is a wavelength at which a transmittance of the first dichroic filter with respect to light incident on the first dichroic filter at the second incident angle is 50%,
λ DM3 is a wavelength width between λ DM1 and λ DM2 ,
λ NF1 is a center wavelength of the first wavelength band of the notch filter, and
λ NF2 is a full width at half maximum (FWHM) of the first wavelength band of the notch filter.
5. The projection image display device according to claim 4 , wherein the notch filter attenuates light of the center wavelength of the first wavelength band by 20% or more.
6. The projection image display device according to claim 1 , wherein
the image forming element further includes a third image forming element that forms a third image,
the color separating and combining unit further includes a second dichroic filter,
the first dichroic filter and the second dichroic filter separate the light from the light source into the first illumination light, the second illumination light, and third illumination light having a wavelength band different from the wavelength band of the first illumination light and the wavelength band of the second illumination light,
the color separating and combining unit emits the first illumination light to the first image forming element, emits the second illumination light to the second image forming element, emits the third illumination light to the third image forming element, and combines the first projection light reflected by the first image forming element, the second projection light reflected by the second image forming element, and third projection light reflected by the third image forming element,
the second dichroic filter reflects the third illumination light and the third projection light,
a third incident angle of the second illumination light with respect to the second dichroic filter is different from a fourth incident angle of the second projection light with respect to the second dichroic filter, and
the notch filter attenuates at least one of the light in the first wavelength band and light in a second wavelength band including a boundary between the wavelength band of the second illumination light and the wavelength band of the third illumination light.
7. The projection image display device according to claim 6 , wherein
the wavelength band of the first illumination light is a red wavelength band,
the wavelength band of the second illumination light is a green wavelength band, and
the wavelength band of the third illumination light is a blue wavelength band.
8. The projection image display device according to claim 7 , wherein
the color separating and combining unit further includes
a first prism that faces the first image forming element,
a second prism that faces the second image forming element, and
a third prism that faces the third image forming element,
the first dichroic filter is disposed between the first prism and the second prism, and
the second dichroic filter is disposed between the first prism and the third prism.
9. The projection image display device according to claim 6 , wherein
when λ DM4 is smaller than λ DM5 , the notch filter satisfies λ DM6 >λ NF4 and λ DM4 +λ DM6 /4≤λ NF3 ≤λ DM5 −λ DM6 /4,
when λ DM4 is larger than λ DM5 , the notch filter satisfies λ DM6 >λ NF4 and λ DM5 +λ DM6 /4≤λ NF3 ≤λ DM4 −λ DM6 /4,
λ DM4 is a wavelength at which a transmittance of the second dichroic filter with respect to light incident on the second dichroic filter at the third incident angle is 50%,
λ DM5 is a wavelength at which a transmittance of the second dichroic filter with respect to light incident on the second dichroic filter at the fourth incident angle is 50%,
λ DM6 is a wavelength width between λ DM4 and λ DM5 ,
λ NF3 is a center wavelength of the second wavelength band of the notch filter, and
λ NF4 is a full width at half maximum (FWHM) of the second wavelength band of the notch filter.
10. The projection image display device according to claim 9 , wherein the notch filter attenuates light of a center wavelength of the first wavelength band by 20% or more, and attenuates light of a center wavelength of the second wavelength band by 20% or more.
11. The projection image display device according to claim 10 , wherein
the notch filter includes
a first notch filter that attenuates the light of the center wavelength of the first wavelength band by 20% or more, and
a second notch filter that attenuates the light of the center wavelength of the second wavelength band by 20% or more.
12. The projection image display device according to claim 11 , wherein
a full width at half maximum of the first notch filter is less than or equal to 25 nm, and
a full width at half maximum of the second notch filter is less than or equal to 25 nm.
13. The projection image display device according to claim 1 , wherein
the color separating and combining unit has an incident surface on which the light from the light source is incident, and
the notch filter is disposed on the incident surface of the color separating and combining unit.
14. The projection image display device according to claim 1 , wherein the image forming element is a digital micromirror device (DMD).
15. The projection image display device according to claim 1 , wherein
the light source illuminates visible light, and
the visible light has continuous spectral characteristics.
16. The projection image display device according to claim 1 , wherein
the light intensity distribution uniformizing unit is a rod integrator.
17. A projection image display device, comprising:
a light source that illuminates light;
an image forming element that includes a first image forming element that forms a first image, and a second image forming element that forms a second image;
a color separating and combining unit that includes a first dichroic filter that separates the light from the light source into first illumination light and second illumination light having a wavelength band different from a wavelength band of the first illumination light, the color separating and combining unit emitting the first illumination light to the first image forming element, emitting the second illumination light to the second image forming element, and combining first projection light reflected by the first image forming element and second projection light reflected by the second image forming element; and
a notch filter that is disposed between the light source and the color separating and combining unit, wherein
the first dichroic filter reflects the first illumination light and the first projection light,
a first incident angle of the first illumination light with respect to the first dichroic filter is different from a second incident angle of the first projection light with respect to the first dichroic filter,
the notch filter attenuates light in a first wavelength band including a boundary between the wavelength band of the first illumination light and the wavelength band of the second illumination light,
when λ DM1 is smaller than λ DM2 , the notch filter satisfies λ DM3 >λ NF2 and λ DM1 +λ DM3 /4≤λ NF1 ≤λ DM2 −λ DM3 /4,
when λ DM1 iS larger than λ DM2 , the notch filter satisfies λ DM3 >λ NF2 and λ DM2 +λ DM3 /4≤λ NF1 ≤λ DM1 −λ DM3 /4,
λ DM1 is a wavelength at which a transmittance of the first dichroic filter with respect to light incident on the first dichroic filter at the first incident angle is 50%,
λ DM2 is a wavelength at which a transmittance of the first dichroic filter with respect to light incident on the first dichroic filter at the second incident angle is 50%,
λ DM3 is a wavelength width between λ DM1 and λ DM2 ,
λ NF1 is a center wavelength of the first wavelength band of the notch filter, and
λ NF2 is a full width at half maximum (FWHM) of the first wavelength band of the notch filter.