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EP-4318108-B1 - LIQUID CRYSTAL LIGHT CONTROL DEVICE

EP4318108B1EP 4318108 B1EP4318108 B1EP 4318108B1EP-4318108-B1

Inventors

  • IKEDA, KOJIRO
  • KOITO, TAKEO
  • KUROKAWA, TAE

Dates

Publication Date
20260506
Application Date
20220308

Claims (10)

  1. A liquid crystal light control device (100), comprising: a first liquid crystal cell (10); a second liquid crystal cell (20) overlapping the first liquid crystal cell (10); a third liquid crystal cell (30) overlapping the second liquid crystal cell (20); and a fourth liquid crystal cell (40) overlapping the third liquid crystal cell (30), each of the first liquid crystal cell (10), the second liquid crystal cell (20), the third liquid crystal cell (30), and the fourth liquid crystal cell (40) includes: a first substrate (S11, S12, S13, S14) including a first alignment film (AL11); a second substrate (S21, S22, S23, S24) including an electrode having a strip pattern and a second alignment film (AL12); and a liquid crystal layer between the first substrate (S11, S12, S13, S14) and the second substrate (S21, S22, S23, S24), wherein an alignment direction of the first alignment film (AL11) and an alignment direction of the second alignment film (AL12) are aligned to intersect each other, and wherein a longitudinal direction of the strip pattern of the electrode having the strip pattern is arranged to intersect an alignment direction of the second alignment film (AL12), and the electrode having the strip pattern is configured such that when the electrode is driven, a transverse electric field is generated in the same direction as the alignment direction of the second alignment film (AL12).
  2. The liquid crystal light control device (100) according to claim 1, wherein: a longitudinal direction of the strip pattern of the electrodes having the strip pattern is arranged in a first direction in each of the first liquid crystal cell (10) and the second liquid crystal cell (20); and a longitudinal direction of the strip pattern of the electrodes having the strip pattern is arranged in a second direction intersecting the first direction in each of the third liquid crystal cell (30) and the fourth liquid crystal cell (40), wherein the first direction intersects an alignment direction of the first alignment film (AL11), and the second direction intersects the alignment direction of the second alignment film (AL12).
  3. The liquid crystal light control device (100) according to claim 1, wherein the electrode having the strip pattern includes at least one first strip electrode having the strip pattern and at least one second strip electrode having the strip pattern, wherein the at least one first strip electrode and the at least one second strip electrode are arranged alternately at a distance.
  4. The liquid crystal light control device (100) according to claim 3, wherein the first strip electrode and the second strip electrode are configured to generate a transverse electric field when driven.
  5. The liquid crystal light control device (100) according to claim 1, wherein the liquid crystal layer is a twisted nematic liquid crystal.
  6. The liquid crystal light control device (100) according to claim 1, wherein the first substrate (S11, S12, S13, S14) is arranged with a flat plate electrode.
  7. A liquid crystal light control device (100), comprising: a first liquid crystal cell (10); a second liquid crystal cell (20) overlapping the first liquid crystal cell (10); a third liquid crystal cell (30) overlapping the second liquid crystal cell (20); and a fourth liquid crystal cell (40) overlapping the third liquid crystal cell (30), the first liquid crystal cell (10), the second liquid crystal cell (20), the third liquid crystal cell (30), and the fourth liquid crystal cell (40) are arranged in this order, each of the first liquid crystal cell (10), the second liquid crystal cell (20), the third liquid crystal cell (30), and the fourth liquid crystal cell (40) includes: a first substrate (S11, S12, S13, S14) including a first electrode (E11, E21, E31, E41) having a strip pattern and a first alignment film (AL11); a second substrate (S21, S22, S23, S24) including a second electrode (E12, E22, E32, E42) having a strip pattern and a second alignment film (AL12); and a liquid crystal layer between the first substrate (S11, S12, S13, S14) and the second substrate (S21, S22, S23, S24), wherein: an alignment direction of the first alignment film (AL11) and an alignment direction of the second alignment film (AL12) are arranged to intersect each other; a longitudinal direction of the strip pattern of the first electrode (E11, E21, E31, E41) and a longitudinal direction of the strip pattern of the second electrode (E12, E22, E32, E42) are arranged to intersect each other; and the longitudinal direction of the strip pattern of the second electrode (E12, E22, E32, E42) is arranged to intersect the alignment direction of the second alignment film (AL12), wherein: the second electrodes (E12, E22, E32, E42) of the first liquid crystal cell (10) and the third liquid crystal cell (30) are configured to generate a transverse electric field in the same direction as the alignment direction of the second alignment film (AL12) when driven, and the first electrodes (E11, E21, E31, E41) of the second liquid crystal cell (20) and the fourth liquid crystal cell (40) are configured to generate a transverse electric field in the same direction as the alignment direction of the first alignment film (AL11) when driven.
  8. The liquid crystal light control device (100) according to claim 7, wherein: the alignment direction of the second alignment film (AL12) of the first liquid crystal cell (10) intersects the alignment direction of the second alignment film (AL12) of the third liquid crystal cell (30); and the alignment direction of the first alignment film (AL11) of the second liquid crystal cell (20) intersects the alignment direction of the first alignment film (AL11) of the fourth liquid crystal cell (40).
  9. The liquid crystal light control device (100) according to claim 7 or 8, wherein: the first electrode (E11, E21, E31, E41) includes at least one first strip electrode having the strip pattern and at least one second strip electrode having the strip pattern, the at least one first strip electrode and the at least one second strip electrode arranged apart and alternating; and the second electrode (E12, E22, E32, E42) includes at least one third strip electrode having the strip pattern and at least one fourth strip electrode having the strip pattern, and the at least one third strip electrode and the at least one fourth strip electrode are arranged apart and alternately.
  10. The liquid crystal light control device (100) according to claim 7, wherein the liquid crystal layer is a twisted nematic liquid crystal.

Description

TECHNICAL FIELD An embodiment of the present invention relates to a device that controls the light distribution of light emitted from a light source using the electrooptical effect of liquid crystals. BACKGROUND ART There is known technology to control the light distribution of light emitted from a light source by using a liquid crystal element. For example, a lighting device that controls the spread of light emitted from a light source by using a liquid crystal cell with concentric circular electrodes is disclosed (refer to Patent Literature 1 and 2). Patent Literature 3 generally discloses liquid crystal light beam control devices and their manufacture. Beneficial aspects of beam broadening devices employed for controlled illumination and architectural purposes are presented including improving beam divergence control, improving beam broadening dynamic range control, beam divergence preconditioning, improving projected beam intensity uniformity and reducing color separation in the projected beam. Both beam control devices having in-plane and homeotropic ground state liquid crystal alignment are presented. CITATION LIST PATENT LITERATURE Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2010-230887Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2005-317879Patent Literature 3: US 2019/025657 A1 SUMMARY OF INVENTION TECHNICAL PROBLEM A liquid crystal element using nematic liquid crystals can rotate the direction of polarized components of an incident light (such phenomenon is also referred to as optical rotation). It is also possible to diffuse incident light by generating a refractive index distribution in the liquid crystal layer. In such a liquid crystal element, when the incident light is diffused by the liquid crystal layer and then rotated, the loss of the rotated light may be large, and the shape of the light distribution pattern may be distorted. One of the purposes of an embodiment of the present invention is to provide a liquid crystal light control device in which the loss of light is prevented, and the disturbance of the light distribution pattern is suppressed. SOLUTION TO PROBLEM The present invention provides liquid crystal light control devices, having the features of respective independent claims. The dependent claims relate to preferred embodiments. A liquid crystal light control device in an embodiment according to the present invention includes a first liquid crystal cell, a second liquid crystal cell overlapping the first liquid crystal cell, a third liquid crystal cell overlapping the second liquid crystal cell, and a fourth liquid crystal cell overlapping the third liquid crystal cell. Each of the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, and the fourth liquid crystal cell includes a first substrate including a first alignment film, a second substrate including an electrode having a strip pattern and a second alignment film, a liquid crystal layer between the first substrate and the second substrate, and an alignment direction of the first alignment film and an alignment direction of the second alignment film are aligned to intersect each other. A longitudinal direction of the strip pattern of the electrode having the strip pattern is arranged to intersect an alignment direction of the second alignment film, and a transverse electric field is generated in the same direction as the alignment direction of the second alignment film. A liquid crystal light control device in an embodiment according to the present invention includes a first liquid crystal cell, a second liquid crystal cell overlapping the first liquid crystal cell, a third liquid crystal cell overlapping the second liquid crystal cell, and a fourth liquid crystal cell overlapping the third liquid crystal cell. Each of the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, and the fourth liquid crystal cell includes a first substrate including a first electrode having a strip pattern and a first alignment film, a second substrate including a second electrode having a strip pattern and a second alignment film, a liquid crystal layer between the first substrate and the second substrate, an alignment direction of the first alignment film and an alignment direction of the second alignment film are arranged to intersect each other, a longitudinal direction of the strip pattern of the first electrode and a longitudinal direction of the strip pattern of the second electrode are arranged to intersect each other, and the longitudinal direction of the strip pattern of the second electrode is arranged to intersect the alignment direction of the second alignment film. The second electrodes of the first liquid crystal cell and the third liquid crystal cell generate a transverse electric field in the same direction as the alignment direction of the second alignment film, and the first electrodes of th