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US 8,998,423 B2Granted
Image Projection apparatus
AssigneeKonica Minolta CPTO, Inc.
InventorYasumasa Sawai
Life of this patent
Estimating the term…
Abstract
Assuming that a normal line of an image display surface of a DMD is a normal line Ax of the image display surface, that a direction in which a light beam specularly reflected by a mirror is outputted is a specular reflection direction R, and that an angle that the specular reflection direction R forms with respect to the normal line Ax of the image display surface is denoted by γ, an image projection apparatus satisfies the following conditional expression: β(2·k−1)≧2·γ−β(2·k)≧β(2·k+1), where β(2·k−1) and β(2·k+1) represent a diffraction angle of an odd-order diffracted light, and β(2·k) represents a diffraction angle of an even-order diffracted light.
Claims7
An image projection apparatus, comprising:
- a light source formed with a discharge lamp;
- a display device which displays blue, green, and red images by modulating illumination light from the light source at pixels;
- and
- a projection lens which projects the blue, green, and red images which are displayed at the display device,
- wherein
- the display device is formed with a digital micromirror device which reflects the illumination light with mirrors functioning as the pixels such that, as ON-light, light representing the image is directed to the projection lens, and, as OFF-light, light not representing the image is directed to an outside of the projection lens;
- and
- the following conditional expression is satisfied:
- β(2·k−1)≧2·γ−β(2·k)≧β(2·k+1),
- where
- β(m) denotes a diffraction angle of an mth-order diffracted light beam resulting from diffraction that occurs when the illumination light is incident on an image display surface of the display device, β(m) satisfying the following equation:
- β(m)=sin−1 {sin α−m·λ/√2·d)};
- γ denotes an angle that is, when a beam of the illumination light incident on the display device is specularly reflected by the mirrors of the display device which output the ON-light, formed between a direction in which the specularly reflected beam of the illumination light is outputted and a normal line of the image display surface, γ satisfying the following equation:
- γ=α−2·θ;
- d denotes a pixel pitch of the display device;
- α denotes an incidence angle of a beam of the illumination light incident on the display device with respect to the normal line of the image display surface;
- θ denotes a tilt angle of a normal line of the mirrors of the display device which output the ON-light with respect to the normal line of the image display surface;
- λ denotes a wavelength, the wavelength being 480 nm in a case of blue image display, 550 nm in a case of green image display, and 620 nm in a case of red image display;
- m denotes a positive integer;
- and
- k denotes a negative integer.
18 more elements
An image projection apparatus, comprising:
- a laser light source which emits blue, green, and red laser light;
- a display device which displays blue, green, and red images by modulating illumination light from the laser light source at pixels;
- and
- a projection lens which projects the blue, green, and red images which are displayed at the display device,
- wherein
- the display device is formed with a digital micromirror device which reflects the illumination light with mirrors functioning as the pixels such that, as ON-light, light representing the image is directed to the projection lens, and, as OFF-light, light not representing the image is directed to an outside of the projection lens;
- and
- the following conditional expression is satisfied:
- β(2·k−1)≧2·γ−β(2·k)≧β(2·k+1),
- where
- β(m) denotes a diffraction angle of an mth-order diffracted light beam resulting from diffraction that occurs when the illumination light is incident on an image display surface of the display device, β(m) satisfying the following equation:
- β(m)=sin−1 {sin α−m·λ(√2·d)};
- γ denotes an angle that is, when a beam of the illumination light incident on the display device is specularly reflected by the mirrors of the display device which output the ON-light, formed between a direction in which the specularly reflected beam of the illumination light is outputted and a normal line of the image display surface, γ satisfying the following equation:
- γ=α−2·θ;
- d denotes a pixel pitch of the display device;
- α denotes an incidence angle of a beam of the illumination light incident on the display device with respect to the normal line of the image display surface;
- θ denotes a tilt angle of a normal line of the mirrors of the display device which output the ON-light with respect to the normal line of the image display surface;
- λ denotes a wavelength, the wavelength being a wavelength of blue laser light emitted from the laser light source in a case of blue image display, a wavelength of green laser light emitted from the laser light source in a case of green image display, and a wavelength of red laser light emitted from the laser light source in a case of red image display;
- m denotes a positive integer;
- and
- k denotes a negative integer.
18 more elements
Dependencies are inferred from the claim text.