Virtual screen display device

• US 6,545,803 B1
• Filed: 05/07/2001
• Issued: 04/08/2003
• Est. Priority Date: 08/25/1997
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Sakuma, Nobuo, Momose, Akira, Obu, Makoto
• Primary Examiner(s): CHANG, AUDREY Y
• Application Number:
  US09/850,120
• Time in Patent Office: 701 Days
• Field of Search: 359/462, 359/472, 359/464, 359/649, 359/630, 359/631, 345/7, 345/8, 345/9, 348/51-52
• US Class Current: 359/472
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• CPC Class Codes: G02B 2027/0136 with a single image source for both eyes
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00

Abstract

A virtual screen display apparatus includes a display arranged to generate display information and having an effective diagonal length DLC and an optical projecting element arranged to receive the display information from the display and to project and form an image, the optical projecting element having an effective F number which is defined by Fe=S1/PuD wherein S1 is a distance between the display and a principal point of the optical projecting element and PuD is a diameter of an exit pupil of the optical projecting element. A field optical element arranged to form an in-space image in a position of a virtual screen and to direct a divergent light flux from the virtual screen to a view region where the image is viewable to an observer. A diameter of a range in which the image is viewable to the observer in the view region is ERD and a diagonal length of the virtual screen is VSD and a distance between the virtual screen and the view region is VSP, and the following equation is satisfied:

VSD/VSP=DLC/(ERD×Fe).

Claims

1. A virtual screen stereoscopic display apparatus, comprising:

at least two displays arranged to display characters and image information;

at least two optical projection elements arranged to enlarge, project and form real images of object images displayed by the at least two displays in a display space, the real images formed by the at least two optical projection elements being projected in-space images; and

at least one optical focusing system arranged to position light fluxes received from the two projected in-space images at two predetermined view regions, respectively;

wherein centers of said two view regions are spaced apart from each other in a transverse direction,

wherein said at least two displays have an effective diagonal length DLC;

said at least two optical projection elements have an effective F number which is defined by Fe=S1/PuD wherein S1 is a distance between the display and a principal point of the two optical projection elements and PuD is a diameter of an exit pupil of the two optical projection elements; and

wherein a diameter of a range in which the image is viewable to the observer in the view region is ERD and a diagonal length of the virtual screen is VSD and a distance between the virtual screen and the view region is VSP, and the following equation is satisfied;

2. The virtual screen stereoscopic display apparatus according to claim 1, wherein the centers of said two view regions are spaced from each other by an approximate distance of about 60 mm to 70 mm.

3. The virtual screen stereoscopic display apparatus according to claim 1, wherein said two view regions are overlapped by about 7 mm or less.

4. The virtual screen stereoscopic display apparatus according to claim 1, wherein each of said two displays comprises at least one of a cathode ray tube, a liquid crystal display, a digital mirror device and a display means which can display an output from a computer, a television or display generating device.

5. The virtual screen stereoscopic display apparatus according to claim 1, wherein said two displays are arranged to display right-eye image information on a left side and left-eye image information on a right side when a person is opposed to the two displays.

6. The virtual screen stereoscopic display apparatus according to claim 1, wherein said optical focusing system comprises at least one of a concave mirror, a reflective image forming element, a positive lens, a transmission type image forming element, a Fresnel optical element, a hologram and an optical diffraction element.

7. A virtual screen stereoscopic display apparatus, comprising:

at least two display means for displaying characters and image information;

at least two optical projection means for enlarging, projecting and forming real images of object images displayed by the at least two displays in a display space, the real images formed by the at least two optical projection means being projected in-space images; and

at least one optical focusing means for positioning light fluxes received from the two projected in-space images at two predetermined view regions, respectively;

wherein centers of said two view regions are spaced apart from each other in a transverse direction,

wherein said at least two display means have an effective diagonal length DLC;

said at least two optical projection means have an effective F number which is defined by Fe=S1/PuD wherein S1 is a distance between the display and a principal point of the two optical projection means and PuD is a diameter of an exit pupil of the two optical projection means; and

wherein a diameter of a range in which the image is viewable to the observer in the view region is ERD and a diagonal length of the virtual screen is VSD and a distance between the virtual screen and the view region is VSP, and the following equation is satisfied;

8. The virtual screen stereoscopic display apparatus according to claim 7, wherein the centers of said two view regions are spaced from each other by an approximate distance of about 60 mm to 70 mm.

9. The virtual screen stereoscopic display apparatus according to claim 7, wherein said two view regions are overlapped by about 7 mm or less.

10. The virtual screen stereoscopic display apparatus according to claim 7, wherein each of said two display means comprises at least one of a cathode ray tube, a liquid crystal display, a digital mirror device and a display means which can display an output from a computer, a television or display generating device.

11. The virtual screen stereoscopic display apparatus according to claim 7, wherein said two display means are arranged to display right-eye image information on a left side and left-eye image information on a right side when a person is opposed to the two display means.

12. The virtual screen stereoscopic display apparatus according to claim 7, wherein said optical focusing means comprises at least one of a concave mirror, a reflective image forming element, a positive lens, a transmission type image forming element, a Fresnel optical element, a hologram and an optical diffraction element.