Collimating optical member for real world simulation

• US 6,853,491 B1
• Filed: 11/26/2003
• Issued: 02/08/2005
• Est. Priority Date: 11/26/2003
• Status: Active Grant

• Current Assignee: eMagin Corporation (Samsung Electronics Co. Ltd.)
• Original Assignee: Ruhle Companies, Inc.
• Inventors: Weissman, Paul, Ruhle, Frank
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Dinh, Jack
• Application Number:
  US10/723,395
• Time in Patent Office: 440 Days
• Field of Search: 359/618, 359/626, 359629-631, 359/633, 359485-487, 349/11, 349/13, 349/98, 349/115
• US Class Current: 359/630
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528

Abstract

A collimating image-forming apparatus comprising a first linear polarizer is disclosed. A first quarter-wave plate is disposed adjacent the first polarizer and has its fast and slow axes at substantially 45° to the plane of polarization of the first polarizer. The apparatus further comprises a beam-splitting curved mirror having a convex surface adjacent the first polarizer and facing towards the first quarter-wave plate, a second quarter-wave plate adjacent the concave side of the curved mirror, the second quarter-wave plate having its having its fast and slow axes oriented with respect to the corresponding axes of the first quarter-wave plate at angles substantially equal to a first integral multiple of 90°, and a reflective-transmissive polarizing member adjacent the second quarter-wave plate. A second linear polarizer is adjacent the reflective-transmissive polarizing member, the second linear polarizer having its plane of polarization oriented with respect to the plane of polarization of the first linear polarizer at an angle substantially equal to a second integral multiple of 90°, both of the multiples being even or both being odd.

Claims

1. An optical system for presenting virtual optical images of an image source outputting light in a forward direction at a desired apparent distance comprising:

(a) a first linear polarizing element oriented to receive light from said image source and output first linearly polarized light having an orientation in a first direction, said first linear polarizing element being oriented in said first direction;

(b) a first elliptical polarizing member oriented in a second direction and positioned to receive said first linearly polarized light and output first elliptically polarized light, said first elliptically polarized light being oriented in a first elliptical direction;

(c) a partially transparent and partially reflective focusing member positioned to receive said first elliptically polarized light and transmit a portion of said first elliptically polarized light;

(d) a second elliptical polarizing member positioned to receive said portion of said first elliptically polarized light from said focusing member and transmit said portion of said first elliptically polarized light as second linearly polarized light, said second linearly polarized light being oriented in said first direction; and

(e) a reflective-transmissive polarizer configured and positioned to reflect light having a linear polarization in said first direction and transmit light having a linear polarization in a direction transverse to said first direction, said second elliptical polarizing member being configured and positioned to convert linearly polarized light reflected in a rearward direction by said reflective-transmissive polarizer into second elliptically polarized light with said second elliptically polarized light being polarized in said first elliptical direction, said concave mirror being positioned to reflect in a forward direction said second elliptically polarized light as third elliptically polarized light, said third elliptically polarized light having a second elliptical direction different from said first elliptical direction, and said second elliptical polarizing member being positioned to convert said third elliptically polarized light into third linearly polarized light, transmitting said third linearly polarized light in a forward direction, said third linearly polarized light being oriented in a second direction transverse to said first direction, whereby said reflective-transmissive polarizer transmits said third linearly polarized light in a forward direction.

2. An optical system as in claim 1, further comprising:

(f) a second linear polarizing element oriented to receive light from said reflective-transmissive polarizer, said second linear polarizing element being configured and positioned to transmit light having a linear polarization in said second direction.

3. An optical system as in claim 1, wherein said elliptical polarizing members are circular polarizing members.

4. An optical system as in claim 3, wherein said circular polarizing members are quarter wave plates.

5. An optical system as in claim 1, wherein said elliptical polarizing members are manufactured using a coating process.

6. An optical system as in claim 1, wherein said reflective-transmissive polarizer is formed of a liquid crystal material.

7. An optical system as in claim 1, wherein said elliptical polarizing members are coated onto opposite sides of said partially transparent and partially reflective concave mirror.

8. An optical system as in claim 1, wherein said elliptical polarizing members are circular polarizing members and said circular polarizing members are quarter wave plates.

9. An optical system as in claim 1, wherein said reflective-transmissive polarizer comprises a wire grid.

10. An optical system as in claim 1, wherein said first and second elliptical polarizing members are one quarter wave retarders comprising liquid crystal materials configured to incorporate characteristics tailored to correct darkened corner phenomenon.

11. An optical system as in claim 1, wherein said first and second elliptical polarizing members are configured to incorporate characteristics tailored to correct darkened corner phenomenon.

12. An optical system as in claim 1, further comprising an image source comprising a polarized projector and a screen fabricated with liquid crystal materials that largely maintain the linear polarization of said projector.

13. An optical system as in claim 1, wherein said reflective-transmissive polarizer comprises a liquid crystal member.