Aspheric mirror, projection-type image displaying apparatus and method of producing projection-type image displaying apparatus
View Patent ↗An aspheric mirror has an aspheric reflective surface symmetrical with respect to an optical axis that goes through the reflective surface and a reference plane provided in the reflective surface. The optical axis may go through the reflective surface at a non-center position on the reflective surface. The reference plane may be perpendicular to the optical axis. The reference plane may be flat enough for a beam to be reflected from the reference plane in almost specular reflection when emitted to the reference plane.
1. An aspheric mirror comprising:
an aspheric reflective first surface having a first optical axis along which a first beam is to be emitted to the reflective first surface; and
an aspheric second surface that is formed continuous with the reflective first surface to constitute an aspheric surface and that is symmetrical with respect to a second optical axis that goes through a center of the second surface and that is not parallel with the first optical axis, the second surface being connected to a section that extends to a bottom surface,
wherein the bottom surface acts as a reference plane with respect to a second beam to be emitted along the second optical axis to the second surface.
2. The aspheric mirror according to claim 1 wherein the second optical axis goes through the aspheric surface constituted by the first and second surfaces at a non-center position on the aspheric surface constituted by the first and second surfaces.
3. The aspheric mirror according to claim 1 wherein the bottom surface is perpendicular to the second optical axis.
4. The aspheric mirror according to claim 1 wherein the bottom surface is flat enough for a beam to be reflected from the bottom surface in almost specular reflection when emitted to the bottom surface.
5. A projection-type image displaying apparatus comprising:
an optical block to emit a first beam carrying an image through optical modulation;
an aspheric mirror having an aspheric reflective surface having a first optical axis along which the first beam is emitted to the reflective first surface; and
an aspheric second surface that is formed continuous with the reflective first surface to constitute an aspheric surface and that is symmetrical with respect to a second optical axis that goes through the second surface and that is not parallel with the first optical axis, the second surface being connected to a section that extends to a bottom surface,
wherein the bottom surface acts as a reference plane with respect to a second beam to be emitted along the second optical axis to the second surface, the optical block and the mirror being arranged for the first beam to be emitted to and reflected from the reflective first surface; and
a screen to display the image carried by the beam reflected from the reflective first surface.
6. The apparatus according to claim 5 wherein the second optical axis goes through the aspheric surface constituted by the first and second surfaces at a non-center position on the aspheric surface constituted by the first and second surfaces.
7. The aspheric mirror according to claim 5 wherein the bottom surface is perpendicular to the second optical axis.
8. The aspheric mirror according to claim 5 wherein the bottom surface is flat enough for a beam to be reflected from the bottom surface in almost specular reflection when emitted to the bottom surface.