Image display apparatus

• US 6,490,086 B2
• Filed: 11/26/1997
• Issued: 12/03/2002
• Est. Priority Date: 12/09/1996
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Morishima, Hideki
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): LEROUX, ETIENNE PIERRE
• Application Number:
  US08/979,329
• Publication Number:
  US 20020001127A1
• Time in Patent Office: 1,833 Days
• Field of Search: 345/7, 345/8, 345/9, 348/115, 353/7, 359/630, 359/631, 359/632, 359/633, 359/13, 359/19
• US Class Current: 359/443
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G03B 21/56 Projection screens

Abstract

An image display apparatus includes an image generator for displaying an image on a display surface constituted by a plurality of pixels, an illuminator for illuminating the image, and an optical system for guiding a light beam outgoing from the illuminated image to the pupil of the obesever. This causes the observer to observe a virtual image formed by the light beam image. In addition, a angle converter sets a first direction and a second direction substantially perpendicular thereto on the plane of formation of the virtual image and causes the light beam outgoing from each pixel to be incident on the optical system making diverging angles in the first and second directions different.

Claims

1. An image display apparatus comprising:

a display for displaying an image on a display surface having a plurality of pixels;

a light source for illuminating said display;

a microlens array having a plurality of microlenses, each of which corresponds to one of said plurality of pixels of said display, said microlens array being disposed at a light source side or a side opposite to the light source with respect to said display, each of said plurality of microlenses having focal lengths differing in a vertical direction and a horizontal direction; and

an optical system for guiding the image displayed on said display toward an eye of an observer, said optical system being common to all of said pixels of said display, with said optical system providing an exit pupil having different widths in vertical and horizontal directions formed substantially at a position where the pupil of the observer is present due to difference in focal lengths in the vertical and horizontal directions in each of said microlenses of said microlens array.

2. An apparatus according to claim 1, wherein the focal length of each of said plurality of microlenses in the vertical direction is longer than the focal length of each of said plurality of microlenses in the horizontal direction.

3. An apparatus according to claim 2, wherein a light beam emerging from each pixel of said display is adapted to pass through said corresponding microlens, and the light beams from all pixels of said display are guided through said optical system to a position where the pupil of the observer is positioned.

4. An apparatus according to claim 2, wherein a light beam from said light source is adapted to be converged by each microlens of said microlens array, and the light beam from each microlens is incident on the corresponding pixel of said display, and the light beams from all pixels of said display are guided through said optical system to a position where the pupil of the observer is positioned.

5. An apparatus according to claim 2, wherein each microlens has an anamorphic form.

6. An apparatus according to claim 2, wherein each microlens has a cylindrical form.

7. An apparatus according to claim 2, wherein two pairs of peripheral rays, respectively in the vertical and horizontal directions, of the light beam perpendicularly emitted from said light source, converged by said microlens and incident on each pixel of said display are converted into two pairs of peripheral rays having different divergent angles in the vertical direction and the horizontal direction by the action of said microlens to illuminate the image, and a distance q_H between the pair of peripheral rays in the horizontal direction and a distance q_V between the pair of peripheral rays in the vertical direction at the exit pupil of said optical system after passing through said optical system satisfy the following conditions:

8. An apparatus according to claim 2, wherein two pairs of peripheral rays, respectively in the vertical and horizontal directions, of the light beam emerging from each pixel of said display are converted into two pairs of peripheral rays having different divergent angles in the vertical direction and the horizontal direction by the action of said microlens, and a distance q_H between the pair of peripheral rays in the horizontal direction and a distance q_V between the pair of peripheral rays in the vertical direction at the exit pupil of said optical system after passing through said optical system satisfy the following conditions:

9. An apparatus according to claim 1, wherein said microlens array is disposed at the side opposite to the light source with respect to said display, and light from each pixel of said display is guided to said optical system through a corresponding microlens.

10. An image observing apparatus comprising:

a display having a plurality of pixels;

an optical system for guiding image information displayed on said display toward an eye of an observer; and

an optical member for differentiating a diverging angle of a light beam outgoing from said display in a first direction from a diverging angle in a second direction substantially perpendicular to said first direction, wherein

an exit pupil of said optical system has different widths in said first and second directions.

11. An image observing apparatus comprising:

a display;

a light source for illuminating said display;

an optical system for guiding image information displayed on said display toward an eye of an observer; and

an optical member for differentiating a diverging angle of a light beam outgoing from said display in a first direction from a diverging angle in a second direction substantially perpendicular to said first direction, said optical member being disposed on a side of said light source with respect to said display, wherein

an exit pupil of said optical system has different widths in said first and second directions.