Reflective optical system, tracking system and holographic projection system and method

• US 8,120,828 B2
• Filed: 02/06/2007
• Issued: 02/21/2012
• Est. Priority Date: 05/12/2006
• Status: Active Grant

• Current Assignee: SeeReal Technologies S.A.
• Original Assignee: SeeReal Technologies S.A.
• Inventors: Schwerdtner, Armin
• Primary Examiner(s): Chang, Audrey Y
• Application Number:
  US12/300,476
• Publication Number:
  US 20090310197A1
• Time in Patent Office: 1,841 Days
• Field of Search: 359/9, 359/13, 359/15, 359/22, 359/32, 345/32
• US Class Current: 359/15
• CPC Class Codes: G02B 27/0037 with diffracting elements G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876
• CPC Class Codes: G02B 27/0068 having means for controlling the degree of correction, e.g. using phase modulators, movable elements controlling the phase of light using moving or deformable elements G02B26/06
• CPC Class Codes: G02B 27/4211 correcting chromatic aberrations G02B27/0056, G02B27/4222, G02B27/4227 take precedence
• CPC Class Codes: G02B 27/4294 in multispectral systems, e.g. UV and visible
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G02F 1/1354 having a particular photoconducting structure or material
• CPC Class Codes: G02F 2203/01 transmissive
• CPC Class Codes: G02F 2203/12 spatial light modulator
• CPC Class Codes: G02F 2203/50 Phase-only modulation
• 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 1/2205 using downstream optical component
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator

Abstract

The invention relates to an optical reflection system with a reflection element for reflecting reconstruction light waves, an entry-side focal point, from which the reconstruction light waves come when they hit the reflection element, and an exit-side focal point, to which the reconstruction light waves propagate after being reflected from the reflection element. The invention further relates to a tracking system and a holographic projection system with such optical reflection system, and a corresponding holographic projection method. In order to achieve with such an optical reflection system an aberration correction and a tracking of the visibility region and a reconstruction larger than with prior art devices, the optical reflection system according to this invention comprises a deflection element with optically controllable deflection properties and a deflection control means for optically controlling the deflection properties of the deflection element which controls the position of at least the exit-side focal point of the optical reflection system.

Claims

1. Holographic projection system for projecting a holographically reconstructed scene, comprising

Reconstruction light source means for generating reconstruction light waves,

At least one holographic reconstruction means in the form of a spatial light modulator for modulating the reconstruction light waves and for emitting modulated reconstruction light waves towards a pupil, which is disposed in a Fourier plane of the spatial light modulator for filtering the modulated reconstruction light waves, and further comprising

An optical reflection system with

A reflection element for reflecting the modulated reconstruction light waves which are filtered by the pupil, said reflection element having an elliptically curved reflecting surface with an entry-side focal point disposed in the pupil, from which the reconstruction light waves come when they hit the reflection element, and an exit-side focal point, to which the reconstruction light waves propagate after being reflected from the reflection element, and in front of which the scene is holographically reconstructed,

A deflection element with optically controllable deflection properties, and

A deflection control means for optically controlling the deflection properties of the deflection element for controlling the position of the exit-side focal point to a position of observer eyes as detected by an eye position detection means.

2. Holographic projection system according to claim 1, where the deflection control means is provided for optically controlling the deflection properties of the deflection element for controlling the position of the entry-side focal point.

3. Holographic projection system according to claim 1, where the deflection control means is provided for optically controlling the deflection properties of the deflection element for correcting aberrations.

4. Holographic projection system according to claim 1, where the reflection element is at least partly transparent.

5. Holographic projection system according to claim 1, where the reflection element is integrated into the deflection element.

6. Holographic projection system according to claim 1, where the deflection element has an optically controllable diffractive or refractive structure or where the deflection element has an optically controllable diffractive and refractive structure.

7. Holographic projection system according to claim 1, where the deflection element is an optically addressable spatial light modulator.

8. Holographic projection system according to claim 7, where the optically addressable spatial light modulator comprises

A first glass plate with a transparent electrode,

An LC layer which comprises LC (liquid crystal) molecules whose orientation can be changed by way of optical control,

A photosensitive semiconductor layer, and

A second glass plate.

9. Holographic projection system according to claim 8, where the photosensitive semiconductor layer is at least partly transparent.

10. Holographic projection system according to claim 8, where the semiconductor layer exhibits a band structure which is affectable by the deflection control means.

11. Holographic projection system according to claim 1, where the deflection control means for controlling the deflection properties of the deflection element is disposed in the entry-side focal point and facing away from the exit-side focal point.

12. Holographic projection system according to claim 1, where the deflection control means comprises two interfering coherent light sources, where for controlling the deflection properties of the deflection element the two interfering coherent light sources are disposed in the entry-side focal point and in the exit-side focal point, and whose interference pattern controls the deflection properties of the deflection element.

13. Holographic projection system according to claim 1, where the deflection control means is designed in the form of an electronically addressable spatial light modulator for projecting writing light onto the deflection element, the deflection element being designed in the form of an optically addressable spatial light modulator and the deflection properties of the deflection element being controlled by the writing light.

14. Holographic projection system according to claim 1, where the deflection control means is a scanning laser beam which is intensity-controlled, for scanning the deflection element.

15. Holographic projection system according to claim 1, where the optical reflection system comprises a dichroic layer or where the reflection element exhibits dichroic properties, where the reconstruction light waves and the writing light provided by the deflection control means differ in wavelength and where the deflection properties of the deflection element are controlled by the writing light.

16. Holographic projection system according to claim 1, where the optical reflection system comprises a reflective polarisation filter or where the reflection element exhibits the properties of a polarisation filter, where the reconstruction light waves and the writing light provided by the deflection control means differ in polarisation and where the deflection properties of the deflection element are controlled by the writing light.

17. Holographic projection system according to claim 1, where the deflection control means for controlling the deflection properties of the deflection element provides writing light in a wavelength range which is invisible for the human eye.

18. Holographic projection system according to claim 1, comprising a position control means for controlling the position of the pupil or of an identical image of the pupil to the entry-side focal point of the optical reflection system.

19. Holographic projection method for projecting holographically reconstructed scenes, comprising the steps of

Generation of modulated reconstruction light waves by a holographic reconstruction means in the form of a spatial light modulator,

Positioning of an entry-side focal point of an elliptically curved reflecting surface of an optical reflection system and a pupil disposed in a Fourier plane of the spatial light modulator in relation to each other,

Filtering the modulated reconstruction light waves towards the optical reflection system with the help of the pupil,

Reflection of the filtered, modulated reconstruction light waves from the elliptically curved reflecting surface of the optical reflection system and generation of a holographic reconstruction of a scene in front of an exit-side focal point of the elliptically curved reflecting surface of the optical reflection system,

Optical control of the deflection properties of a deflection element of the optical reflection system for controlling the position of the exit-side focal point of the elliptically curved reflecting surface of the optical reflection system to a position of observer eyes as detected by an eye position detection means.