Microdisplay viewer

• US 6,452,577 B1
• Filed: 11/05/1999
• Issued: 09/17/2002
• Est. Priority Date: 11/06/1998
• Status: Expired due to Term

• Current Assignee: Kopin Corporation, Massachusetts Institute of Technology
• Original Assignee: Kopin Corporation
• Inventors: Swanson, Gary J., Gale, Ronald P.
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Kovalick, Vincent E.
• Application Number:
  US09/434,726
• Time in Patent Office: 1,047 Days
• Field of Search: 345/7, 345/8, 345/84, 345/87, 345/100, 345/102, 345/905, 349/58, 349/61, 349/62, 349/64, 349/67, 359/630, 359/631
• US Class Current: 345/87
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: H04M 1/72409 by interfacing with external accessories hands-free H04M1/60
• CPC Class Codes: H04N 9/3141 Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: Y10S 345/905 Display device with housing structure

Abstract

A display viewer has an electronic display including an array of pixel electrodes having an area of less than 400 mm². A light source can be used to illuminate the array of pixel electrodes of a liquid crystal display in a preferred embodiment. The viewer has a lens system that enlarges an image on the display and can also include a mirror that reflects the enlarged image from the lens. A display viewer in a preferred embodiment has a planar mirror and a viewing screen. The viewing screen has a diffuser and a Fresnel lens through which the image is viewed.

Claims

1. A display viewer comprising:

an electronic display having an array of pixel electrodes having an area of less than 400 mm²;

a lens that enlarges an image on the display; and

a curved mirror that reflects the enlarged image from the lens, the curved mirror having an optical axis and a principal focal surface intersecting the optical axis at a focal point.

2. The display viewer of claim 1 wherein the electronic display is an active matrix display and further comprising a light source that illuminates the array of pixel electrodes.

3. The display viewer of claim 2 wherein the microdisplay further comprises a light pipe between the light source and the liquid crystal display.

4. The display viewer of claim 3 wherein the microdisplay further comprises a condenser lens between the light pipe and the liquid crystal display.

5. The display viewer of claim 2 wherein the light source comprises at least one light emitting diode.

6. The display viewer of claim 2 wherein the light source further comprises at least one dichroic filter.

7. The display viewer of claim 1 further comprising a screen for displaying the image projected from the mirror.

8. The display viewer of claim 7 wherein the screen comprises a diffuser and Fresnel lens.

9. The display viewer of claim 7 further comprising a housing:

the housing carrying the liquid crystal display, the mirror and the screen;

the screen pivotably carried by the housing for moving between an open viewing position and a closed stored position; and

a backlight that illuminates the array of pixel electrodes.

10. The display viewer of claim 9 wherein the mirror is positioned in a range of between 40 millimeters and 50 millimeters from the microdisplay and the mirror is located between 22 millimeters and 30 millimeters from the screen when in an open viewing position.

11. The display viewer of claim 10 wherein the screen for displaying the image is greater than 28 millimeters by 38 millimeters.

12. A display viewer comprising:

an electronic display including an array of pixel electrodes;

a lens that enlarges an image on the electronic display; and

a curved mirror that reflects the enlarged image from the lens, the curved mirror having an optical axis and a principal focal surface intersecting the optical axis at a focal point.

13. A microdisplay viewer comprising:

a display having an array of at least 35,000 pixel electrodes having an active area of less than 400 mm₂;

a lens that gathers and enlarges the image on the microdisplay; and

a curved mirror that reflects the enlarged image from the lens, the curved mirror having an optical axis and a principal focal surface intersecting the optical axis at a focal point.

14. The microdisplay viewer of claim 13 wherein the display is an active matrix liquid crystal display and further comprising a light source that illuminates the array of pixel electrodes.

15. The microdisplay viewer of claim 14 wherein the display has an array of at least 75,000 pixel electrodes having an active area of less than 200 mm².

16. The microdisplay viewer of claim 15 wherein the microdisplay further comprises a light pipe between the light source and the liquid crystal display.

17. The microdisplay viewer of claim 16 wherein the microdisplay further comprises a condenser lens between the light pipe and the liquid crystal display.

18. The microdisplay viewer of claim 14 wherein the light source comprises at least one light emitting diode.

19. The microdisplay viewer of claim 14 wherein the light source further comprises at least one dichroic filter.

20. The microdisplay viewer of claim 14 further comprising a screen for displaying the image projected from the mirror.

21. The microdisplay viewer of claim 20 wherein the screen comprises a diffuser and Fresnel lens.

22. The microdisplay viewer of claim 20 further comprising:

a housing, the housing carrying the liquid crystal display, the mirror and the screen;

the screen pivotably carried by the housing for moving between an open viewing position and a closed stored position; and

where the light source is a backlight that illuminates the array of pixel electrodes.

23. The microdisplay viewer of claim 22 wherein the mirror is positioned in a range of between 40 millimeters and 50 millimeters from the microdisplay and the mirror is located between 22 millimeters and 30 millimeters from the screen when in an open viewing position.

24. The microdisplay viewer of claim 23 wherein the screen for displaying the image is greater than 28 millimeters by 38 millimeters.

25. A microdisplay viewer comprising:

a display having an array of at least 35,000 pixel electrodes having an active area of less than 400 mm²;

a lens that gathers and enlarges the image on the microdisplay;

a screen that displays the enlarged image from the lens; and

a folding mirror interposed between the lens and the screen to reflect the enlarged image from the lens to the screen.

26. The microdisplay viewer of claim 25 wherein the screen is a Fresnel lens.

27. The microdisplay viewer of claim 25 wherein the screen is a combination Fresnel lens and a diffuser.

28. A microdisplay viewer comprising:

an active matrix liquid crystal display including an array of at least 75,000 pixel electrodes, the array of pixel electrodes having an active area of less than 200 mm²;

a light source that illuminates the array of pixel electrodes;

a lens that enlarges an image on the microdisplay; and

a curved mirror that reflects the enlarged image from the lens, the curved mirror having an optical axis and a principal focal surface intersecting the optical axis at a focal point.

29. The microdisplay viewer of claim 28 wherein the active matrix liquid crystal display is a color sequential display.

30. The microdisplay viewer of claim 29 wherein the array of pixel electrodes has an active area of less than 158 mm².

31. The microdisplay viewer of claim 28 wherein the microdisplay further comprises a light pipe between the light source and the liquid crystal display.

32. The microdisplay viewer of claim 31 wherein the microdisplay further comprises a condenser lens between the light pipe and the liquid crystal display.

33. The microdisplay viewer of claim 28 wherein the light source comprises a light emitting diode.

34. The microdisplay viewer of claim 28 wherein the light source further comprises at least one dichroic filter.

35. The microdisplay viewer of claim 28 wherein the plane of the microdisplay is maintained at a non-perpendicular angle to the optical axis of the concave mirror.

36. The microdisplay viewer of claim 28 wherein the concave mirror is a parabolic mirror so that the focal surface and the corresponding surface are both planes perpendicular to the optic axis.

37. The microdisplay viewer of claim 28 further comprising a digital camera.

38. The microdisplay viewer of claim 28 wherein the viewer further comprises a wired link for connecting to a cellular telephone having:

a telephone housing having a plurality of control elements;

an active matrix liquid crystal display within the housing and including an array of at least 75,000 pixel electrodes, the array of pixel electrodes having an active area of less than 158 mm²;

a light emitting diode device that illuminates the array of pixel electrodes; and

a lens positioned to receive an image formed on the active matrix liquid crystal display and that magnifies the image.

39. The microdisplay viewer of claim 28 wherein the viewer further comprises a wired link for connecting to a wireless pager having:

a housing having a plurality of control elements;

a wireless receiver within the housing that receives data from a source;

a display circuit connected to the wireless receiver;

a matrix display mounted to the housing and that displays an image from the circuit, the matrix display having at least 75,000 pixel electrodes defining an active area of less that 160 mm²; and

the housing comprises a first display port for the matrix display and a second display port for viewing an alphanumeric display.

40. A cellular telephone comprising:

a telephone housing having a plurality of control elements;

an active matrix liquid crystal display within the housing and including an array of at least 75,000 pixel electrodes, the array of pixel electrodes having an active area of less than 158 mm²;

a light emitting diode device that illuminates the array of pixel electrodes;

a lens positioned to receive an image formed on the active matrix liquid crystal display and magnify the image; and

a curved mirror that reflects the magnified image from the lens, the curved mirror having an optical axis and a principal focal surface intersecting the optical axis at a focal point.

41. A wireless pager comprising:

a housing having a plurality of control elements;

a wireless receiver within the housing that receives data from a source;

a display circuit connected to the wireless receiver;

a matrix display mounted to the housing and that displays an image from the circuit,

the matrix display having at least 75,000 pixel electrodes defining an active area of less than 160 mm²;

a light emitting diode device that illuminates the array of pixel electrodes;

a lens that gathers and enlarges the image on the microdisplay; and

a curved mirror that reflects the enlarged image from the lens, the curved mirror having an optical axis and a principal focal surface intersecting the optical axis at a focal point,

the housing having a first display port for the matrix display and a second display port for viewing an alphanumeric display.