Slim optical projection system and image display apparatus employing the same

• US 20060066760A1
• Filed: 09/22/2005
• Published: 03/30/2006
• Est. Priority Date: 09/24/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Inventors: Cho, Kun-ho, Sokolov, Kirill, Borodouline, Alexei
• Granted Patent: US 7,448,756 B2
• Time in Patent Office: Days
• US Class Current: 348/744
• CPC Class Codes: G02B 17/08 Catadioptric systems used in non-imaging applications G02B19/00
• CPC Class Codes: G02B 17/0852 having a field corrector only
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G03B 21/10 Projectors with built-in or built-on screen
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• CPC Class Codes: H04N 9/3141 Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14

Abstract

A slim optical projection system and an image display apparatus employing the same. The optical projection system includes: a relay lens group to produce an intermediate image from an image created by a display and to generate a first distortion in the intermediate image, a projection lens group to enlarge and project the intermediate image that passes through the relay lens group and to generate a second distortion in the projected image, and a reflector to reflect the image enlarged by the projection lens group to a screen at a wide viewing angle. The first and second distortions are used to compensate for a third distortion caused by the reflector

Claims

1. An optical projection system, comprising:

a relay lens group to produce an intermediate image from an image created by a display and to generate a first distortion in the intermediate image;

a projection lens group to enlarge and project the intermediate image that passes through the relay lens group and to generate a second distortion in the projected image; and

a reflector to reflect the image enlarged by the projection lens group onto a screen at a wide viewing angle,

wherein the first and second distortions compensate for a third distortion caused by the reflector.

2. The optical projection system of claim 1, wherein the reflector comprises an aspherical mirror.

3. The optical projection system of claim 1, wherein the reflector has a negative refractive power.

4. The optical projection system of claim 1, further comprising:

first and second optical path changers to change optical paths between the relay lens group and the projection lens group and between the projection lens group and the reflector, respectively.

5. The optical projection system of claim 4, further comprising:

a third optical path changer disposed within the relay lens group.

6. The optical projection system of claim 4, wherein the first, second, and third optical path changers comprise one of a mirror and a total reflection prism.

7. The optical projection system of claim 1, wherein an optical axis of the display is coaxial with optical axes of the relay lens group and the projection lens group.

8. The optical projection system of claim 7, wherein an optical axis of the reflector is offset from the optical axis of the display.

9. The optical projection system of claim 1, wherein the first and second distortions are spool distortions, and the third distortion caused by the reflector is a barrel distortion.

10. An optical projection system usable with an image display apparatus, comprising:

a preliminary distortion unit to receive an image created by an image creation unit and to induce a preliminary distortion in the received image; and

an image enlarging unit to receive the preliminary distorted image, to enlarge the received-image while inducing a distortion in the received image, and to project the enlarged image onto a screen,

wherein the preliminary distortion compensates for the distortion.

11. The optical projection system of claim 10, wherein the preliminary distortion part comprises at least one of a relay lens group, a projection lens group, and a refractive optical system.

12. The optical projection system of claim 11, wherein the image enlarging unit comprises a reflective optical system.

13. The optical projection system of claim 10, wherein the preliminary distortion unit receives the created image in an opposite direction from the screen and provides the preliminary distorted image toward a rear direction of the image display apparatus, and the image enlarging unit reflects the enlarged image back toward a forward direction of the image display apparatus onto the screen.

14. The optical projection system of claim 10, wherein the preliminary distortion comprises a spool distortion and the distortion comprises barrel distortion.

15. The optical projection system of claim 10, wherein the preliminary distortion unit comprises:

a relay lens group to produce an intermediate image from the image created by the image creation unit and to generate a first distortion in the intermediate image; and

a projection lens group to enlarge and project the intermediate image that passes through the relay lens group to the image enlarging unit and to generate a second distortion in the projected image.

16. The optical projection system of claim 15, wherein the image enlarging unit comprises a reflector to reflect the image enlarged by the projection lens group onto the screen at a wide viewing angle such that the first and second distortions generated in the image compensate for distortion generated when the image is reflected at the wide viewing angle onto the screen.

17. An optical projection system, comprising:

a refractive optical system to enlarge and transmit an image produced by a display;

a reflective optical system to reflect the image transmitted by the refractive optical system at a wide viewing angle; and

a relay lens group disposed between the display and the reflective optical system to preliminarily induce a first distortion to compensate for a third distortion caused by the reflective optical system,

wherein the refractive optical system preliminarily induces a second distortion that is used in combination with the first distortion to compensate for the third distortion caused by the reflective optical system.

18. The optical projection system of claim 17, wherein the reflective optical system comprises an aspherical mirror.

19. The optical projection system of claim 17, wherein the reflective optical system has a negative refractive power.

20. The optical projection system of claim 17, further comprising:

first and second optical path changers to change optical paths between the relay lens group and the refractive optical system and between the refractive optical system and the reflective optical system, respectively.

21. The optical projection system of claim 20, further comprising:

a third optical path changer disposed within the relay lens group.

22. The optical projection system of claim 20, wherein the first, second, and third optical path changers comprise one of a mirror and a total reflection prism.

23. The optical projection system of claim 17, wherein an optical axis of the display is coaxial with optical axes of the relay lens group and the refractive optical system.

24. The optical projection system of claim 23, wherein an optical axis of the reflective optical system is offset from the optical axis of the display.

25. The optical projection system of claim 17, wherein the first and second distortions are spool distortions, and the third distortion caused by the reflective optical system is a barrel distortion.

26. An image display apparatus including a display to receive a beam emitted by a light source and to produce an image by processing the received beam according to an input image signal and an optical projection system to enlarge and project the produced image onto a screen, and the optical projection system comprises:

a relay lens group to produce an intermediate image from the image created by the display and to generate a first distortion in the intermediate image;

a projection lens group to enlarge and project the intermediate image that passes through the relay lens group and to generate a second distortion in the projected image; and

a reflector to reflect the image enlarged by the projection lens group onto the screen at a wide viewing angle,

wherein the first and second distortions are used to compensate for a third distortion caused by the reflector.

27. The apparatus of claim 26, wherein the reflector comprises an aspherical mirror.

28. The apparatus of claim 26, wherein the reflector has a negative refractive power.

29. The apparatus of claim 26, wherein the optical projection system further comprises first and second optical path changers to change optical paths between the relay lens group and the projection lens group and between the projection lens group and the reflector, respectively.

30. The apparatus of claim 29, wherein the optical projection system further comprises a third optical path changer disposed within the relay lens group.

31. The apparatus of claim 29, wherein the first, second, and third optical path changers comprise one of a mirror and a total reflection prism.

32. The apparatus of claim 26, wherein an optical axis of the display is coaxial with optical axes of the relay lens group and the projection lens group.

33. The apparatus of claim 32, wherein an optical axis of the reflector is offset from the optical axis of the display.

34. The apparatus of claim 26, wherein the first and second distortions are spool distortions, and the third distortion caused by the reflector is a barrel distortion.

35. An image display apparatus including a display to receive a beam emitted by a light source and to produce an image by processing the received beam according to an input image signal and an optical projection system to enlarge and project the produced image onto a screen, and the optical projection system comprises:

a refractive optical system to enlarge and transmit the image produced by the display;

a reflective optical system to reflect the image transmitted by the refractive optical system at a wide viewing angle; and

a relay lens group disposed between the display and the reflective optical system to preliminarily induce a first distortion to compensate for a third distortion caused by the reflective optical system,

wherein the refractive optical system preliminarily induces a second distortion that is used in combination with the first distortion to compensate for the third distortion caused by the reflective optical system.

36. The apparatus of claim 35, wherein the reflective optical system comprises an aspherical mirror.

37. The apparatus of claim 35, wherein the reflective optical system has a negative refractive power.

38. The apparatus of claim 35, wherein the optical projection system further comprises first and second optical path changers to change optical paths between the relay lens group and the refractive optical system and between the refractive optical system and the reflective optical system, respectively.

39. An image display apparatus to display an image on a screen, comprising:

an image creation unit to create an image; and

an optical projection system, comprising;

a preliminary distortion unit to receive the image created by an image creation unit and to induce a preliminary distortion in the received image; and

an image enlarging unit to receive the preliminary distorted image, to enlarge the received image while inducing a distortion in the received image, and to project the enlarged image onto a screen,

wherein the preliminary distortion compensates for the distortion.

40. An optical projection system, comprising:

a display to generate an image;

a first lens group to generate a first intermediate image having a first distortion from the image;

a second lens group to generate a second intermediate image having a second distortion from the first intermediate image;

a reflector to introduce a third distortion into the second intermediate image to compensate for the first and second distortions, and to generate a third intermediate image; and

a screen to display the third intermediate image without the first and second distortions.

41. The system of claim 40, wherein the first and second intermediate images have a pincushion shape, and the reflector generates the third intermediate image to have a rectangular shape by introducing the third distortion having a barrel shape.

42. The system of claim 40, wherein the third intermediate image is enlarged from the second intermediate image.

43. An image display apparatus, comprising:

a screen disposed at a front side of the image display apparatus;

an imager creator disposed under the screen at the front side of the image display apparatus to create an image having a plurality of light beams and to transmit the plurality of light beams in a rear direction;

a refractive optical system to receive the plurality of light beams from the image creator and to relay the plurality of light beams along the rear direction while enlarging an angle along which the plurality of light beams propagate and while introducing a predetermined distortion in the image; and

a reflective optical system disposed at a rear side of the image display apparatus to receive the plurality of light beams from the refractive optical system and to reflect the plurality of light beams onto the screen while enlarging the image and introducing another distortion in the image.

44. A method of forming an image in an optical projection system, the method comprising:

receiving an image created by an image creation unit;

creating a predistortion in the received image and providing the predistorted image to a reflector; and

reflecting the predistorted image toward a screen while introducing a distortion that is compensated for by the predistortion.

45. The method of claim 44, wherein the predistoration comprises one or more spool distortions and the distortion comprises a barrel distortion.

46. The method of claim 44, wherein:

creating the predistortion in the received image comprises performing a first enlarging operation using a projection lens group; and

reflecting of the predistorted image toward the screen comprises performing a second enlarging operation using the reflector.