Projection apparatus

• US 5,890,786 A
• Filed: 09/17/1997
• Issued: 04/06/1999
• Est. Priority Date: 04/22/1994
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kurematsu, Katsumi
• Primary Examiner(s): Dowling, William
• Application Number:
  US08/932,348
• Time in Patent Office: 566 Days
• Field of Search: 353/20, 353/34, 353/37, 353/38, 353/84, 353/102, 353/69, 359/40, 359/41, 359/48, 359/49, 349/5, 349/9
• US Class Current: 353/20
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells

Abstract

The present invention relates to a projection apparatus in which a beam of light from light source means is separated into beams of two polarized components by a polarization separator, and the direction of polarization of one of the separated beams of two polarized components is caused to coincide with the direction of polarization of the other beam of light through polarizing rotatable means, whereafter the two beams of light are condensed by a condenser of which the refractive power differs between two directions orthogonal to each other, a projected image is irradiated with the beam of light passed through the condenser and the projected image is projected onto a predetermined surface by a projector.

Claims

1. An apparatus comprising:

information forming means for forming information;

illuminating means for illuminating said information forming means, said illuminating means including a polarization beam splitter disposed in an optical path in said illuminating means and leading to said information forming means; and

optical means disposed near said information forming means for receiving a beam of light output by said illuminating means, said optical means having refracting powers which are different in mutually perpendicular planes for rendering said beam of light output by said illuminating means to have equal expanses in said mutually perpendicular planes, thereby enhancing illumination of the information forming means.

2. An apparatus comprising:

information forming means for forming information;

illuminating means for illuminating said information forming means, said illuminating means including;

a polarization beam splitter disposed in an optical path in said illuminating means and leading to said information forming means; and

a mirror for reflecting light passed through said polarizing beam splitter into said optical path; and

optical means disposed near said information forming means for receiving a beam of light output by said illuminating means, said optical means having refracting powers which are different in mutually perpendicular planes for rendering said beam of light output by said illuminating means to have equal expanses in said mutually perpendicular planes, thereby enhancing illumination of the information forming means.

3. An apparatus comprising:

information forming means for forming information;

illuminating means for illuminating said information forming means, said illuminating means including;

a polarization beam splitter disposed in an optical path in said illuminating means and leading to said information forming means; and

an optical member for varying the polarized state of light reflected by said polarizing beam splitter and for reflecting polarization state-varied light into said optical path; and

optical means disposed near said information forming means for receiving a beam of light output by said illuminating means, said optical means having refracting powers which are different in mutually perpendicular planes for rendering said beam of light output by said illuminating means to have equal expanses in said mutually perpendicular planes, thereby enhancing illumination of the information forming means.

4. An apparatus comprising:

information forming means for forming information; and

illuminating means for illuminating said information forming means, said illuminating means comprising

a) light generating means for generating a light beam having a uniform state of polarization, and

b) optical means for receiving said light beam and modifying an expanse of said light beam perpendicular to a polarizing conversion plane of said light generating means in order to equalize expanses of the beam in mutually perpendicular directions.

5. An apparatus according to claim 4, wherein said light generating means includes a polarization beam splitter disposed in an optical path in said illuminating means and leading to said information forming means.

6. An apparatus according to claim 5, wherein said light generating means includes a mirror for reflecting light passed through said polarizing beam splitter into said optical path.

7. An apparatus according to claim 5, wherein said light generating means includes an optical member for varying the polarized state of light reflected by said polarizing beam splitter and for reflecting polarization state-varied light into said optical path.

8. An apparatus according to claim 4, further comprising a projection lens for projecting the information of said illuminated information forming means.

9. An apparatus according to claim 4, wherein said optical means defines first and second surfaces, both of which are cylindrical surfaces.

10. An apparatus comprising:

information forming means for forming information;

illuminating means for illuminating said information forming means including a polarization beam splitter disposed in an optical path in said illuminating means and leading to said information forming means; and

optical means disposed near said information forming means for rendering a beam of light output by said illuminating means to have equal expanses in mutually perpendicular planes.

11. An apparatus comprising:

information forming means for forming information;

illuminating means for illuminating said information forming means including a polarization beam splitter disposed in an optical path in said illuminating means and leading to said information forming means; and

optical means disposed near said information forming means for relaying illuminating light of said illuminating means toward said information forming means wherein refracting powers of said optical means in mutually perpendicular planes are different for rendering said illuminating light to have equal expanses in mutually perpendicular directions, thereby enhancing illumination of the information forming means.

12. An apparatus according to claim 11, wherein said illuminating means includes a polarization beam splitter disposed in an optical path in said illuminating means and leading to said information forming means.

13. An apparatus according to claim 12, wherein said illuminating means includes a mirror for reflecting light passed through said polarizing beam splitter into said optical path.

14. An apparatus according to claim 12, wherein said illuminating means includes an optical member for varying the polarized state of light reflected by said polarizing beam splitter and for reflecting polarization state-varied light into said optical path.

15. An apparatus comprising:

information forming means for forming information;

illuminating means for illuminating said information forming means and including a polarization beam splitter disposed in an optical path in said illuminating means and leading to said information forming means; and

optical means disposed near said information forming means for receiving a beam of light output by said illuminating means, said optical means having refracting powers which are different in mutually perpendicular planes for rendering said beam of light output by said illuminating means to have equal expanses in said mutually perpendicular planes, thereby enhancing illumination of the information forming means.