Light modulator for a display for displaying two-dimensional and/or three-dimensional image contents

Patent metadata

Field	Value
Publication number	US-10509364-B2
Application number	US-201013499113-A
Country	US
Kind code	B2
Filing date	Sep 29, 2010
Priority date	Sep 29, 2009
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

A light modulator, for a display for the presentation of two- and/or three-dimensional image contents or image sequences, includes two opposing substrates and electrodes. At least one liquid crystal layer is provided between the two substrates. An alignment means is provided on the substrate which faces the liquid crystal layer to set a predeterminable initial alignment of the liquid crystals. The orientation of the liquid crystals can be controlled in a given range through an electric field generated by the electrodes. The alignment means is controllable and can be controlled to modify the initial alignment of the liquid crystals. The alignment can be controlled such the orientation of the liquid crystals can be oriented outside the given range or so that the initial alignment of the liquid crystals can be set specifically for certain positions.

First claim

The invention claimed is:

1. A light modulator for a display for the presentation of two- and/or three-dimensional image contents, comprising:
two opposing substrates and electrodes,
at least one liquid crystal layer is provided between the two substrates,
an alignment means provided on the surface of the substrate which faces the liquid crystal layer to set a predeterminable initial alignment of the liquid crystals, where the orientation of the liquid crystals can be controlled in a predeterminable range through an electric field which is generated by the electrodes,
the alignment means is of a controllable type and is controllable during the operation of the light modulator such that the initial alignment of the liquid crystals is changeable, and
if the initial alignment of the liquid crystals is modified then the alignment of the liquid crystals in an electric field can be controlled such that the orientation of the liquid crystals is orientable outside the given range or such that the initial alignment of the liquid crystals is settable in a predeterminable way in dependency of a predetermined location.

2. Light modulator according to claim 1 , wherein the alignment means can be controlled such that the liquid crystals can rotate in a deterministic way.

3. Light modulator according to claim 1 , further comprising regularly arranged pixels, where the pixels are made such to modulate the phase of the light which interacts with the light modulator, where a pixel preferably modulates the light which interacts with the pixel substantially in the same way across the entire surface of the pixel.

4. Light modulator according to claim 3 , further comprising a reflective working principle, where the liquid crystal layer realises the function of a variable λ/2 plate, where circular polarised light to be modulated passes through the liquid crystals and a λ/4 plate which is disposed downstream of the liquid crystal layer and is reflected by a reflective layer and passes through the λ/4 plate and through the liquid crystal layer again.

5. Light modulator according to claim 3 , further comprising a reflective working principle, where the liquid crystal layer realises the function of a variable λ/4 plate, where circular polarised light to be modulated passes through the liquid crystals and is reflected by a reflective layer and passes through the liquid crystal layer again.

6. Light modulator according to claim 3 , wherein the light which interacts with the light modulator is changeable with a substantially constant phase value substantially across the entire cross section of a pixel of the light modulator.

7. Light modulator according to claim 1 , wherein substantially linear electrodes and/or a planar electrode are provided on at least one substrate.

8. Light modulator according to claim 1 , wherein the surface orientation is set such that the liquid crystals are substantially aligned with a first predeterminable initial alignment in a first local region of the light modulator, in that in a second local region of the light modulator the liquid crystals are aligned by the alignment means with a second predeterminable initial alignment, which is turned by a first angle in relation to the first initial alignment, and in that in a third local region of the light modulator the liquid crystals are aligned by the alignment means with a third predeterminable initial alignment, which is turned in relation to the first initial alignment by a second angle which has substantially the same absolute value as the first angle but which is turned in the opposite direction.

9. Light modulator according to claim 8 , wherein the first predeterminable initial alignment of the liquid crystals is substantially parallel or perpendicular to the surface normal of a substrate.

10. Light modulator according to claim 8 , wherein the first predeterminable initial alignment of the liquid crystals is substantially parallel or perpendicular to the longitudinal axis of substantially linear shaped electrodes.

11. Light modulator according to claim 1 , wherein by applying electric fields of locally different strength and/or direction the liquid crystals can be oriented in a predeterminable way such that a continuous angular distribution of the liquid crystals between 0 and 360 degrees is achieved in relation to the initial alignment with a variably controllable grating period.

12. Light modulator according to claim 1 , wherein at least one temperature sensor is provided for measuring the current temperature of the light modulator in order to take the measured current temperature into account when controlling the light modulator.

13. Light modulator according to claim 1 , further comprising a UV filter for preventing the entry of UV light into the light modulator and thus to slow down chemical ageing of the materials of the light modulator.

14. Light modulator according to claim 1 , wherein FLC molecules or CNTs are directly bonded chemically with a polyimide alignment means—for example via a functional group.

15. A display, in particular to a stereoscopic or holographic display, further comprising a light modulator according to claim 1 .

16. A method for operating a light modulator according to claim 1 , comprising the following process steps:
a) Setting of at least one predeterminable orientation of the liquid crystals and, as the case may be, setting of at least one predeterminable initial alignment of the liquid crystals with the help of the alignment means
b) Setting of an orientation that differs from the predeterminable orientation of the liquid crystals
c) If the orientation that differs from the predeterminable orientation of the liquid crystals lies outside the given range of liquid crystal orientations, setting of a predeterminable initial alignment of the liquid crystals with the help of the alignment means such that the orientation that differs from the predeterminable orientation of the liquid crystals is settable.

Assignees

• Kroll Bo
• Leister Norbert
• Reichelt Stephan
• Futterer Gerald
• Seereal Tech S A

Inventors

• Kroll Bo
• Leister Norbert
• Reichelt Stephan
• Futterer Gerald

Classifications

• G02F1/13363

  Birefringent elements, e.g. for optical compensation · CPC title

• G03H1/2294

  Addressing the hologram to an active spatial light modulator · CPC title

• H04N13/359

  Switching between monoscopic and stereoscopic modes · CPC title

• G03H2001/0224

  Active addressable light modulator, i.e. Spatial Light Modulator [SLM] · CPC title

• G03H1/02 Primary

  Details {of features involved during the holographic process; Replication of holograms without interference recording} · CPC title