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US-12619115-B2 - Optical element

US12619115B2US 12619115 B2US12619115 B2US 12619115B2US-12619115-B2

Abstract

An optical element includes at least two liquid crystal cells. The at least two liquid crystal cells include a first substrate on which a first transparent electrode and a second transparent electrode are alternately and repeatedly arranged in a first direction, a second substrate on which a third transparent electrode and a fourth transparent electrode are alternately and repeatedly arranged in a second direction intersecting the first direction, and a liquid crystal layer between the first substrate and the second substrate. The second transparent electrode comprises a first bent portion bent in the first direction. The fourth transparent electrode comprises a second bent portion bent in the second direction.

Inventors

  • Tae Kurokawa
  • Takeo Koito
  • Kojiro Ikeda

Assignees

  • JAPAN DISPLAY INC.

Dates

Publication Date
20260505
Application Date
20240611
Priority Date
20210218

Claims (18)

  1. 1 . An optical element comprising: at least two liquid crystal cells comprising: a first substrate on which a first transparent electrode and a second transparent electrode are alternately and repeatedly arranged in a first direction; a second substrate on which a third transparent electrode and a fourth transparent electrode are alternately and repeatedly arranged in a second direction intersecting the first direction; and a liquid crystal layer between the first substrate and the second substrate, wherein each of the first transparent electrode and the third transparent electrode has a linear shape, the second transparent electrode comprises a first bent portion bent in the first direction, the fourth transparent electrode comprises a second bent portion bent in the second direction, and a pair of second transparent electrodes adjacent to each other through the first transparent electrode are provided line-symmetrically with respect to an extending direction of the first transparent electrode.
  2. 2 . The optical element according to claim 1 , wherein an inter-substrate distance d between the first substrate and the second substrate and a first maximum pitch p 1 between the first transparent electrode and the second transparent electrode satisfy d/p 1 ≥1.
  3. 3 . The optical element according to claim 2 , wherein d/p 1 ≥2 is satisfied.
  4. 4 . The optical element according to claim 2 , wherein the first maximum pitch p 1 and an inter-electrode distance b1 between the first transparent electrode and the second transparent electrode satisfy p 1 /2≤b1.
  5. 5 . The optical element according to claim 2 , wherein the inter-substrate distance d and a second maximum pitch p 2 between the third transparent electrode and the fourth transparent electrode satisfy d/p 2 ≥1.
  6. 6 . The optical element according to claim 5 , wherein d/p 2 ≥2 is satisfied.
  7. 7 . The optical element according to claim 5 , wherein the second maximum pitch p 2 and a second maximum inter-electrode distance b2 between the third transparent electrode and the fourth transparent electrode satisfy p 2 /2≤b2.
  8. 8 . The optical element according to claim 1 , wherein the at least two liquid crystal cells comprise a first liquid crystal cell and a second liquid crystal cell, the first bent portion of the first liquid crystal cell does not overlap the first bent portion of the second liquid crystal cell, and the second bent portion of the first liquid crystal cell does not overlap the second bent portion of the second liquid crystal cell.
  9. 9 . The optical element according to claim 1 , wherein the at least two liquid crystal cells comprise a first liquid crystal cell and a second liquid crystal cell, and an angle α between an extending direction of the first transparent electrode of the first liquid crystal cell and an extending direction of the first transparent electrode of the second liquid crystal cell is greater than 0 degrees and less than or equal to 4 degrees.
  10. 10 . An optical element, comprising: at least two liquid crystal cells comprising: a first substrate on which a first transparent electrode and a second transparent electrode are alternately and repeatedly arranged in a first direction; a second substrate on which a third transparent electrode and a fourth transparent electrode are alternately and repeatedly arranged in a second direction intersecting the first direction; and a liquid crystal layer between the first substrate and the second substrate, wherein each of the first transparent electrode and the third transparent electrode has a linear shape, the second transparent electrode comprises a first bent portion bent in the first direction, the fourth transparent electrode comprises a second bent portion bent in the second direction, and a pair of second transparent electrodes adjacent to each other through the first transparent electrode have different numbers of the first bent portions.
  11. 11 . The optical element according to claim 10 , wherein an inter-substrate distance d between the first substrate and the second substrate and a first maximum pitch p 1 between the first transparent electrode and the second transparent electrode satisfy d/p 1 ≥1.
  12. 12 . The optical element according to claim 11 , wherein d/p 1 ≥2 is satisfied.
  13. 13 . The optical element according to claim 11 , wherein the first maximum pitch p 1 and an inter-electrode distance b1 between the first transparent electrode and the second transparent electrode satisfy p 1 /2≤b1.
  14. 14 . The optical element according to claim 11 , wherein the inter-substrate distance d and a second maximum pitch p 2 between the third transparent electrode and the fourth transparent electrode satisfy d/p 2 ≥1.
  15. 15 . The optical element according to claim 14 , wherein d/p 2 ≥2 is satisfied.
  16. 16 . The optical element according to claim 14 , wherein the second maximum pitch p 2 and a second maximum inter-electrode distance b2 between the third transparent electrode and the fourth transparent electrode satisfy p 2 /2≤b2.
  17. 17 . The optical element according to claim 10 , wherein the at least two liquid crystal cells comprise a first liquid crystal cell and a second liquid crystal cell, the first bent portion of the first liquid crystal cell does not overlap the first bent portion of the second liquid crystal cell, and the second bent portion of the first liquid crystal cell does not overlap the second bent portion of the second liquid crystal cell.
  18. 18 . The optical element according to claim 10 , wherein the at least two liquid crystal cells comprise a first liquid crystal cell and a second liquid crystal cell, and an angle α between an extending direction of the first transparent electrode of the first liquid crystal cell and an extending direction of the first transparent electrode of the second liquid crystal cell is greater than 0 degrees and less than or equal to 4 degrees.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 18/222,154, filed on Jul. 14, 2023, which application is a continuation of International Patent Application No. PCT/JP2021/046386, filed on Dec. 15, 2021, which claims the benefit of priority to Japanese Patent Application No. 2021-024714, filed on Feb. 18, 2021, the entire contents of which are incorporated herein by reference. FIELD An embodiment of the present invention relates to an optical element using a liquid crystal. BACKGROUND An optical element which is a so-called liquid crystal lens has been conventionally known in which a change in the refractive index of a liquid crystal is utilized by adjusting a voltage applied to the liquid crystal. Further, a lighting device using a light source and a liquid crystal lens has been developed (for example, see Japanese laid-open patent publication No. 2005-317879, 2010-230887, or 2014-160277). SUMMARY An optical element includes at least two liquid crystal cells. The at least two liquid crystal cells include a first substrate on which a first transparent electrode and a second transparent electrode are alternately and repeatedly arranged in a first direction, a second substrate on which a third transparent electrode and a fourth transparent electrode are alternately and repeatedly arranged in a second direction intersecting the first direction, and a liquid crystal layer between the first substrate and the second substrate. The second transparent electrode comprises a first bent portion bent in the first direction. The fourth transparent electrode comprises a second bent portion bent in the second direction. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic perspective view of an optical element according to an embodiment of the present invention. FIG. 2A is a schematic cross-sectional view of an optical element according to an embodiment of the present invention. FIG. 2B is a schematic cross-sectional view of an optical element according to an embodiment of the present invention. FIG. 3A is a schematic cross-sectional view showing an alignment of liquid crystal molecules in a liquid crystal layer in an optical element according to an embodiment of the present invention. FIG. 3B is a schematic cross-sectional view showing an alignment of liquid crystal molecules in a liquid crystal layer in an optical element according to an embodiment of the present invention. FIG. 4A is a schematic cross-sectional view showing an alignment of liquid crystal molecules in a liquid crystal layer when potentials are applied in an optical element according to an embodiment of the present invention. FIG. 4B is a schematic cross-sectional view showing an alignment of liquid crystal molecules in a liquid crystal layer when potentials are applied in an optical element according to an embodiment of the present invention. FIG. 5A is a schematic cross-sectional view illustrating control of a light distribution by an optical element according to an embodiment of the present invention. FIG. 5B is a schematic cross-sectional view illustrating control of a light distribution by an optical element according to an embodiment of the present invention. FIG. 6 is a timing chart showing potentials applied to each transparent electrode included in an optical element according to an embodiment of the present invention. FIG. 7 is a graph showing front relative luminance versus d/p in a liquid crystal cell of an optical element according to an embodiment of the present invention. FIG. 8 is a schematic diagram illustrating a shape and arrangement of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present invention. FIG. 9 is a schematic diagram illustrating a shape and arrangement of a first transparent electrode, a second transparent electrode, a third transparent electrode, and a fourth transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present invention. FIG. 10 is a schematic diagram illustrating a shape and arrangement of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present invention. FIG. 11 is a schematic diagram illustrating a shape and arrangement of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present invention. FIG. 12 is a schematic diagram illustrating a shape and a layout of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present invention. FIG. 13 is a schematic diagram illustrating a shape and a layout of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an opt