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US 7,605,978 B2Granted
Transparent screen and projection display unit
AssigneeMitsubishi Electric Corporation
InventorsTakao Endo, Akihisa Miyata, Takeshi Utakoji, Yuzo Nakano
Life of this patent
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Abstract
A transparent screen and a projection display unit capable of reducing the speckle with maintaining the brightness of the image light. A wavefront-dividing phase-modulating component 21, which divides the wavefront of the image light emitted from a Fresnel lens screen 7 and modulates the phases of the wavefronts divided, is disposed before an optical diffusing component 10. Alternatively, a spatial frequency modulating component 22, which modulates the spatial frequency of the image light diffused by the optical diffusing component 10, is disposed on the light-output side (observer side) of the optical diffusing component 10.
Claims17
A transparent screen comprising:
- a Fresnel optical component for receiving image light radiated from a light-emitting component, and for emitting the image light in a prescribed direction;
- a wavefront-dividing phase-modulating component for dividing a wavefront of the image light emitted from said Fresnel optical component, and for modulating phases of wavefronts divided;
- and
- an optical diffusing component for diffusing the image light, the phases of the wavefronts of which are modulated by said wavefront-dividing phase-modulating component,
- wherein said wavefront-dividing phase-modulating component has curved surfaces or flat surfaces having a unit period equal to or less than particle diameters of optical diffusion beads constituting said optical diffusing component.
2 more elements
A transparent screen comprising:
- a Fresnel optical component for receiving image light radiated from a light-emitting component, and for emitting the image light in a prescribed direction;
- an optical diffusing component for diffusing the image light emitted from said Fresnel optical component;
- and
- a spatial frequency modulating component for modulating a spatial frequency of the image light diffused by said optical diffusing component,
- wherein said Fresnel optical component has prisms formed on an incidence plane side on which the image light radiated from the light-emitting component is incident.
2 more elements
A transparent screen comprising:
- a Fresnel optical component for receiving image light radiated from a light-emitting component, and for emitting the image light in a prescribed direction;
- a wavefront-dividing phase-modulating component for dividing a wavefront of the image light emitted from said Fresnel optical component, and for modulating phases of wavefronts divided;
- and
- an optical diffusing component for diffusing the image light, the phases of the wavefronts of which are modulated by said wavefront-dividing phase-modulating component,
- wherein said Fresnel optical component has prisms formed on an incidence plane side on which the image light radiated from the light-emitting component is incident.
2 more elements
A projection display unit comprising:
- a light-emitting component for radiating image light;
- a Fresnel optical component for receiving the image light radiated from the light-emitting component, and for emitting the image light in a prescribed direction;
- a wavefront-dividing phase-modulating component for dividing a wavefront of the image light emitted from said Fresnel optical component, and for modulating phases of wavefronts divided;
- and
- an optical diffusing component for diffusing the image light, the phases of the wavefronts of which are modulated by said wavefront-dividing phase-modulating components,
- wherein said wavefront-dividing phase-modulating component has curved surfaces or flat surfaces having a unit period equal to or less than particle diameters of optical diffusion beads constituting said optical diffusing component.
3 more elements
A projection display unit comprising:
- a light-emitting component for radiating image light;
- a Fresnel optical component for receiving the image light radiated from the light-emitting component, and for emitting the image light in a prescribed direction;
- an optical diffusing component for diffusing the image light emitted from said Fresnel optical component;
- and
- a spatial frequency modulating component for modulating a spatial frequency of the image light diffused by said optical diffusing components,
- wherein said Fresnel optical component has prisms formed on an incidence plane side on which the image light radiated from the light-emitting component is incident.
3 more elements
A projection display unit comprising:
- a light-emitting component for radiating image light;
- a Fresnel optical component for receiving the image light radiated from the light-emitting component, and for emitting the image light in a prescribed direction;
- a wavefront-dividing phase-modulating component for dividing a wavefront of the image light emitted from said Fresnel optical component, and for modulating phases of wavefronts divided;
- and
- an optical diffusing component for diffusing the image light, the phases of the wavefronts of which are modulated by said wavefront-dividing phase-modulating component,
- wherein said Fresnel optical component has prisms formed on an incidence plane side on which the image light radiated from the light-emitting component is incident.
3 more elements
An image display method employing a transparent screen, the method comprising:
- receiving at a Fresnel optical component of the transparent screen, image light radiated from a light-emitting component, and for emitting the image light in a prescribed direction;
- dividing a wavefront of the image light at a wavefront-dividing phase-modulating component from said Fresnel optical component, and for modulating phases of wavefronts divided;
- and
- diffusing the image light at an optical diffusing component, the phases of the wavefronts of which are modulated by said wavefront-dividing phase-modulating component,
- wherein said wavefront-dividing phase-modulating component has curved surfaces or flat surfaces having a unit period equal to or less than particle diameters of optical diffusion beads constituting said optical diffusing component.
2 more elements
An image display method employing a transparent screen, the method comprising:
- receiving at a Fresnel optical component of the transparent screen, image light radiated from a light-emitting component, and for emitting the image light in a prescribed direction;
- dividing a wavefront of the image light at a wavefront-dividing phase-modulating component from said Fresnel optical component, and for modulating phases of wavefronts divided;
- and
- diffusing the image light at an optical diffusing component, the phases of the wavefronts of which are modulated by said wavefront-dividing phase-modulating component,
- wherein said Fresnel optical component has prisms formed on an incidence plane side on which the image light radiated from the light-emitting component is incident.
2 more elements
An image display method employing a transparent screen, the method comprising:
- receiving at a Fresnel optical component of the transparent screen, image light radiated from a light-emitting component, and for emitting the image light in a prescribed direction;
- diffusing the image light at an optical diffusing component emitted from said Fresnel optical component;
- and
- modulating a spatial frequency component for modulating a spatial frequency of the image light diffused by said optical diffusing component,
- wherein said Fresnel optical component has prisms formed on an incidence plane side on which the image light radiated from the light-emitting component is incident.
2 more elements
Dependencies are inferred from the claim text.