Hologram reconstructing apparatus

• US 5,986,780 A
• Filed: 02/10/1997
• Issued: 11/16/1999
• Est. Priority Date: 09/01/1993
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hasegawa, Eiji, Sudo, Toshiyuki
• Primary Examiner(s): HENRY, JON W
• Application Number:
  US08/797,850
• Time in Patent Office: 1,009 Days
• Field of Search: 359/9, 359/10, 359/11, 359/21, 359/22, 359/24, 359/25, 359/32, 359/33, 359/630, 359/462
• US Class Current: 359/22
• CPC Class Codes: G03H 1/08 Synthesising holograms, i.e. holograms synthesized from objects or objects from hologramsusing electric digital computers G06F; G06T
• CPC Class Codes: G03H 1/22 Processes or apparatus for obtaining an optical image from holograms G03H1/26 - G03H1/34 take precedence
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator

Abstract

This specification discloses a hologram reconstructing apparatus having interference fringe forming means for forming optical interference fringes in conformity with an input signal, information input means for successively inputting different bits of interference fringe information to the interference fringe forming means, and illuminating means for illuminating the interference fringe forming means with a plurality of beams of light differing in wavefront from one another.

Claims

1. A hologram reconstructing apparatus comprising:

a spatial light modulator for changing a light transmission or reflection area thereof so as to display fringe patterns on a single same area whenever the apparatus reconstructs images, said light modulator being controlled in accordance with an input signal;

drive means for driving said spatial light modulator by supplying the input signal to the spatial light modulator, wherein said drive means changes said fringe patterns displayed, and said drive means selectively changes over a plurality of different interference fringes to be displayed on a position of the same single area of said spatial light modulator; and

illuminating means for illuminating each of said fringe patterns on the same single area of said spatial light modulator with a beam of light corresponding to each of said fringe patterns wherein each of the plurality of beams of light illuminates each of said fringe patterns with a mutually different illumination condition, so that hologram images based on each of said plurality of beams are reconstructed in a reconstructing area,

wherein said drive means selects only one pattern of interference fringe to be displayed on said spatial light modulator at a time with respect to said illumination condition and displays the selected pattern of interference fringes on said spatial light modulator.

2. The apparatus according to claim 1, wherein the reconstruction areas of hologram images based on each of said fringe patterns differ from one another.

3. The apparatus according to Claim 1, wherein said illuminating means illuminates said fringe patterns with said beams of light differing in wave front from one another in synchonism with said input signal.

4. The apparatus according to claim 2, wherein the hologram images of which said reconstruction areas differ from one another form a continuous three dimensional image.

5. The apparatus according to claim 2, wherein said drive means changes said fringe patterns displayed within 1/60 second.

6. An apparatus according to claim 2, wherein said illuminating means makes light beams whose wavefronts are mutually different simultaneously incident on said fringe patterns.

7. An apparatus according to claim 2, wherein said illuminating means makes light beams whose wavefronts are mutually different incident on said fringe patterns.

8. An apparatus according to claim 1, wherein a single combination of said interference fringe patterns and illumination conditions is so selected from among a plurality of combinations thereof by said drive means as to minimize the maximum value of spatial frequency of said interference fringe pattern.

9. An apparatus according to claim 2, wherein a single combination of said reconstructing area and illumination conditions at a time is so selected from among a plurality of combinations thereof by said drive means as to minimize the maximum value of spatial frequency of said interference fringe pattern.