Optical system and display that converts a flat image to a non-flat image

• US 8,493,520 B2
• Filed: 05/30/2008
• Issued: 07/23/2013
• Est. Priority Date: 06/01/2007
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Gay, Gregory, Walton, Harry Garth
• Primary Examiner(s): NGO, HUYEN LE
• Application Number:
  US12/602,335
• Publication Number:
  US 20100177113A1
• Time in Patent Office: 1,880 Days
• Field of Search: 349/15, 349113-114
• US Class Current: 349/15
• CPC Class Codes: G02B 3/005 arranged along a single direction only, e.g. lenticular sheets G02B3/0043 takes precedence
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 30/27 involving lenticular arrays

Abstract

An optical system is provided for use with a display device to convert a flat image from the display device to a non-flat image. The optical system comprises first and second spaced-apart partial reflectors, at least one of which is non-flat. The reflectors, together with polarization optics, provide a light path such that light from the display is at least partially transmitted by the first reflector, partially reflected by the second reflector, partially reflected by the first reflector and partially transmitted by the second reflector so that a viewer perceives a non-flat, for example curved, image. Light which does not follow the light path is prevented from leaving the optical system.

Claims

1. An optical system for converting a flat image to a non-flat image, the optical system comprising first and second spaced-apart partial reflectors, at least one of which is non-flat, and providing a first light path for a first light incident on the first reflector, the first light path comprising at least partial transmission through the first reflector towards the second reflector, at least partial reflection from the second reflector towards the first reflector, at least partial reflection from the first reflector towards the second reflector, and at least partial transmission through the second reflector, the optical system being arranged substantially to prevent emission from the second reflector of the first light not reflected during reflection by the first and second reflectors, wherein light incident on the second partial reflector for the first time does not leave the optical system.

2. A system as claimed in claim 1, in which the optical system is arranged to change the polarisation of the first light during passage along the first path.

3. A system as claimed in claim 2, in which the optical system is arranged to change the polarisation of the first light during passage along the first path between incidence on the second reflector and reflection from the first reflector.

4. A system as claimed in claim 1, in which the optical system is switchable to a flat image mode to provide a second light path different from the first path.

5. A system as claimed in claim 4, in which the second light path comprises at least partial transmission through the first reflector towards the second reflector and at least partial transmission through the second reflector.

6. A system claimed in claim 5, in which the optical system is arranged substantially to prevent emission from the second reflector of a second light not transmitted by the second reflector in the flat image mode.

7. A system as claimed in any one of the preceding claims claim 1, including a lens arrangement for at least partially correcting for image distortion by the or each non-flat one of the first and second reflectors.

8. A system as claimed in claim 1, in which the at least one of the first and second reflectors is continuously curved in at least one direction for producing a concave or convex image.

9. A system as claimed in claim 1, in which the at least one of the first and second reflectors comprises a plurality of flat segments, adjacent ones of which abut each other along an edge and subtend an angle greater than 0°

and less than 180°

.

10. A system as claimed in claim 1, in which the at least one of the first and second reflectors has a serpentine cross-section.

11. A system as claimed in claim 1, in which both of the first and second reflectors are non-flat.

12. A system as claimed in claim 11, in which the first and second reflectors have mirror-image shapes.

13. A system as claimed in claim 1, comprising at least one quarter wave plate.

14. A system as claimed in claim 13, in which the quarter wave plate or a second of the quarter wave plates is disposed between the first and second reflectors.

15. A system as claimed in claim 13, in which the quarter wave plate or a first of the quarter wave plates is disposed on a side of the first reflector opposite the second reflector.

16. A system as claimed in claim 1, in which the first reflector comprises a first partial mirror.

17. A system as claimed in claim 16, in which the first partial mirror comprises a patterned mirror associated with an array of converging lenses.

18. A system as claimed in claim 1, in which the first reflector comprises a first reflective polariser.

19. A system as claimed in claim 1, in which the second reflector comprises a second reflective polariser.

20. A system as claimed in claim 19, in which the second reflective polariser comprises a cholesteric reflector.

21. A system as claimed in claim 20, in which the cholesteric reflector is disablable.

22. A system as claimed in claim 19, in which the second reflective polariser is non-flat and in which the system comprises a first prism arranged to redirect light from the first partial reflector to be incident substantially normally on the second reflective polariser.

23. A system as claimed in claim 22, comprising a second prism film arranged to redirect light from the second reflective polariser to the direction of light incident on the first prism film.

24. A system as claimed in claim 1, in which the second reflector comprises a second partial mirror.

25. A system as claimed in claim 1, comprising a half wave plate.

26. A system as claimed in claim 25, in which the half wave plate is disablable.

27. A system as claimed in claim 25, in which the half wave plate is a directional half wave plate.

28. A system as claimed in claim 1, comprising a Faraday rotator.

29. A system as claimed in claim 28, in which the Faraday rotator is arranged to provide 45°

of polarisation rotation.

30. A system as claimed in claim 1, in which the at least one of the first and second reflectors is of controllable variable shape.

31. A system as claimed in claim 1, comprising an input linear polariser.

32. A system as claimed in claim 1, comprising an output linear polariser.