Viewing device

• US 5,719,588 A
• Filed: 06/28/1996
• Issued: 02/17/1998
• Est. Priority Date: 03/08/1991
• Status: Expired due to Fees

• Current Assignee: Microsharp Corporation Limited
• Original Assignee: NASHUA CORPORATION (Cenveo Incorporated), Nashua Photo Limited
• Inventors: Johnson, William Nevil Heaton
• Primary Examiner(s): Saras, Steven
• Application Number:
  US08/671,008
• Time in Patent Office: 599 Days
• Field of Search: 345/7, 345/8, 345/9, 345/84, 348/51-54, 351/158, 359/629, 359/630, 430/321, 349/11, 349/57
• US Class Current: 345/8
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: H04N 13/189 Recording image signals; Reproducing recorded image signals
• CPC Class Codes: H04N 13/194 Transmission of image signals
• CPC Class Codes: H04N 13/204 using stereoscopic image cameras stereoscopic photography G03B35/00
• CPC Class Codes: H04N 13/286 having separate monoscopic and stereoscopic modes
• CPC Class Codes: H04N 13/324 Colour aspects
• CPC Class Codes: H04N 13/344 with head-mounted left-right displays
• CPC Class Codes: H04N 13/361 Reproducing mixed stereoscopic images; Reproducing mixed monoscopic and stereoscopic images, e.g. a stereoscopic image overlay window on a monoscopic image background
• CPC Class Codes: H04N 13/363 using image projection screens volumetric display H04N13/388
• CPC Class Codes: H04N 5/72 Modifying the appearance of television pictures by optical filters or diffusing screens
• CPC Class Codes: H04N 5/7491 of head mounted projectors

Abstract

A viewing device for receiving video signals and generating corresponding images for viewing comprising a frame or support, adapted to be worn on the user'"'"'s head, for example, a frame similar to a spectacle frame. The frame supports a pixelated LCD screen in front of each of the wearer'"'"'s eyes. Respective optical systems located between the user'"'"'s eyes and the screens allow the user to view the images generated as if they were at infinity. A light-transmitting microlens screen may be located in front of each LCD screen to produce an improved subjective viewing impression by "de-pixelating" the image.

Claims

1. A viewing device comprising a frame or support adapted to be worn on the user'"'"'s head and supporting, so as to be in front of each of the user'"'"'s eyes, a respective video display screen, driving circuitry driving said displays, a respective optical system, supported by said frame or support, interposed between each eye and the respective screen and a respective diffusing or randomising screen interposed between the respective display screen and the respective optical system, such that the light diffusing screen acts as a spatial filter removing the high spatial frequency image detail which is due to pixelation leaving only the lower spatial frequencies corresponding to actual picture content, whereby the pixels are rendered imperceptible, each said video display screen comprising an LCD-pixelated screen, each said diffusing or randomising screen comprising a sheet of light-transmitting material in or on which is formed an array of closely packed microlenses, said microlenses being substantially smaller than the pixels of said LCD-pixelated screen.

2. A display device comprising a video display screen comprising a plurality of individual pixels, and a light diffusing or randomising screen placed in front of the display screen and exposed to direct view in such a way that the diffusing or randomising screen is interposed between the display screen and the viewer, such that the light diffusing or randomising screen acts as a spatial filter removing the high spatial frequency image detail which is due to the pixelation leaving only the lower spatial frequencies corresponding to actual picture content, whereby the pixels are rendered imperceptible, each said video display screen comprising an LCD-pixelated screen, each said diffusing or randomising screen comprising a sheet of light-transmitting material in or on which is formed an array of closely packed microlenses, said microlenses being substantially smaller than the pixels of said LCD-pixelated screen.

3. A viewing device comprising a frame or support adapted to be worn on the user'"'"'s head and supporting, so as to be in front of each of the user'"'"'s eyes, a respective video display screen, driving circuitry driving said displays, a respective optical system, supported by said frame or support, interposed between each eye, and the respective screen and a respective diffusing or randomising screen interposed between the respective display screen and the respective optical system, such that the light diffusing screen acts as a spatial filter removing the high spatial frequency image detail which is due to pixelation leaving only the lower spatial frequencies corresponding to actual picture content, whereby the pixels are rendered imperceptible, wherein the light diffusing or randomising screen comprises a sheet of light transmitting material in or on which is formed, an array of closely packed microlenses having a diameter of between 5 and 1 microns.

4. A viewing device according to claim 3 wherein each said video display screen comprises an LCD pixelated screen.

5. A viewing device according to claim 3 wherein each said diffusing or randomising screen comprises a sheet of light transmitting material in which said lenses are formed by localised variations in the refractive index of the sheet material whereby the lenses are of the graded refractive index type.

6. A viewing device according to claim 3 wherein the diameter of each microlens is between 5 and 2 microns.

7. A viewing device according to claim 3 wherein each said video display screen comprises an LCD screen arranged to be back-lit by ambient light or by a diffuse light source and wherein a further diffusing screen is located behind each LCD screen to improve uniformity of backlighting.

8. A viewing device according to claim 3 including respective energising circuitry for each said video display screen whereby said screens may be arranged to display, in each of a succession of display periods, a respective image of a stereoscopic image pair.

9. A viewing device according to claim 3 wherein said driving circuitry includes means for energising the two video display screens to display during each of a succession of frame periods, respective images of a respective stereoscopic image pair, whereby the user can perceive video programme material stereoscopically.

10. A method of removing visually obtrusive detail of the pixelation of a pixilated video display comprising disposing in front of the display, between the display and the viewer, a light diffusing or randomising screen such that the light diffusing screen acts as a spatial filter removing the high spatial frequency image detail which is due to pixelation leaving only the lower spatial frequencies corresponding to actual picture content, whereby the pixels are rendered imperceptible, wherein the light diffusing or randomising screen comprises an array of closely packed microlenses having a diameter between 5 and 1 microns.

11. A display device comprising a video display screen comprising a plurality of individual pixels, and a light diffusing or randomising screen placed in front of the display screen and exposed to direct view in such a way that the diffusing or randomising screen is interposed between the display screen and the viewer, such that the light diffusing or randomising screen acts as a spatial filter removing the high spatial frequency image detail which is due to the pixelation leaving only the lower spatial frequencies corresponding to actual picture content, whereby the pixels are rendered imperceptible, wherein the light diffusing or randomising screen comprises an array of closely packed microlenses having a diameter of between 5 and 1 microns.

12. A display device according to claim 11 wherein the video display screen comprises an LCD screen arranged to be backlit by ambient light or by a diffuse light source and wherein a further diffusing or randomising screen is located behind each LCD screen to improve uniformity of backlighting.

13. A device according to claim 11 wherein said further diffusing or randomising screen located behind the LCD screen comprises a light transmitting sheet incorporating an array of closely packed microlenses.