Light modulation device

Patent metadata

Field	Value
Publication number	US-12298635-B2
Application number	US-201917268698-A
Country	US
Kind code	B2
Filing date	Jul 1, 2019
Priority date	Aug 16, 2018
Publication date	May 13, 2025
Grant date	May 13, 2025

Abstract

The invention relates to a light modulation device for a complex-valued modulation of linearly polarized incident light, comprising a first light modulator, a subsequently arranged second light modulator and at least one polarizer, where the first light modulator and the second light modulator are configured as phase modulators, where a modulation axis of the first light modulator is aligned at an angle to the modulation axis of the second light modulator, and where the polarization direction of the light incident on the first light modulator and the polarization direction of the polarizer are respectively aligned at predetermined non-90° angles with respect to the modulation axis of the first light modulator and the modulation axis of the second light modulator.

First claim

The invention claimed is:

1. A light modulation device for a complex-valued modulation of linearly polarized incident light, comprising a first light modulator, a subsequently arranged second light modulator and at least one polarizer, where the first light modulator and the second light modulator are configured as phase modulators, where a modulation axis of the first light modulator is aligned at an angle to a modulation axis of the second light modulator, where a polarization direction of the light incident on the first light modulator and a polarization direction of the polarizer are respectively aligned at predetermined non-90° angles with respect to the modulation axis of the first light modulator and the modulation axis of the second light modulator, and where a phase shift is respectively adjustable over a range of at least 2π for the first light modulator and for the second light modulator.

2. The light modulation device as claimed in claim 1 , wherein the angle between the modulation axes of the first light modulator and of the second light modulator is between 60° and 120°.

3. The light modulation device as claimed in claim 1 , wherein the polarization direction of the polarizer is aligned at an angle of between 80° and 100° with respect to the polarization direction of the light incident on the first light modulator, or in that the polarization direction of the polarizer is aligned at an angle of between −10° and +10° with respect to the polarization direction of the light incident on the first light modulator.

4. The light modulation device as claimed in claim 1 , wherein the predetermined angle between the polarization direction of the light incident on the first light modulator and the modulation axis of the first light modulator is between 30° and 60°.

5. The light modulation device as claimed in claim 1 , wherein a further polarizer is arranged before the first light modulator in the light propagation direction.

6. The light modulation device as claimed in claim 1 , wherein the first light modulator and the second light modulator are respectively configured as a controllable birefringent liquid-crystal layer.

7. The light modulation device as claimed in claim 1 , wherein the first light modulator and the second light modulator are directly connected to one another.

8. The light modulation device as claimed in claim 1 , wherein the first light modulator and the second light modulator have at least one common substrate.

9. A display device, in particular a holographic display device, for the representation of at least one of two-dimensional and three-dimensional scenes, where the display device comprises a light modulation device as claimed in claim 1 .

10. The display device as claimed in claim 9 , wherein an illumination device is assigned to the display device, and in that the illumination device emits coherent or linearly polarized coherent light.

11. A method for a complex-valued modulation of linearly polarized light comprising a first light modulator, a subsequently arranged second light modulator and at least one polarizer, where a light component, oscillating in a direction of a modulation axis of the first light modulator, of the light is adjustably retarded in its phase by the first light modulator, where a light component, oscillating in a direction of a modulation axis of the second light modulator, of the light is adjustably retarded in its phase by the second light modulator, where the modulation axis of the first light modulator is aligned transversely, in particular perpendicularly, with respect to the modulation axis of the second light modulator, where the light emerging from the second light modulator is linearly polarized by the polarizer aligned at a non-90° angle with respect to the modulation axes, and where a phase shift is respectively adjustable over a range of at least 2π for the first light modulator and for the second light modulator.

12. The method as claimed in claim 11 , wherein a phase of the light emerging from the polarizer, for an equal amplitude, is modified in that phase retardations of the light component modulated by the first light modulator and of the light component modulated by the second light modulator are modified by an equal value.

13. The method as claimed in claim 11 , wherein an amplitude of the light emerging from the polarizer, for an equal phase, is modified in that phase retardations of the light component modulated by the first light modulator and of the light component modulated by the second light modulator are modified oppositely by the same magnitude.

Assignees

• Seereal Technolgies S A
• Seereal Tech S A

Inventors

• Leister Norbert

Classifications

• G02F1/1393

  the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells (G02F1/1396, G02F1/141 take precedence) · CPC title

• G02F1/13471 Primary

  in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells (G02F1/13475 takes precedence) · CPC title