In-plane switching liquid crystal display

• US 10,180,598 B2
• Filed: 10/26/2016
• Issued: 01/15/2019
• Est. Priority Date: 10/26/2016
• Status: Active Grant

• Current Assignee: A.U. Vista Inc. (AUO Corp.)
• Original Assignee: A.U. Vista Inc. (AUO Corp.)
• Inventors: Lan, Yi-Fen
• Primary Examiner(s): Glick, Edward
• Assistant Examiner(s): Liu, Shan
• Application Number:
  US15/334,460
• Publication Number:
  US 20180113362A1
• Time in Patent Office: 811 Days
• Field of Search: 349139-148, 349129
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133531 characterised by the arrangement of polariser or analyser axes
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/137 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
• CPC Class Codes: G02F 1/13793 Blue phases
• CPC Class Codes: G02F 2201/124 interdigital

Abstract

An in-plane switching liquid crystal display having a plurality of protrude electrodes of a special shape is disclosed. Each of the protrusion electrodes has a protrusion body with a surface coated with an electrically conductive material. The protrusion body has flat side located on the lower substrate of the liquid crystal display, defining the basewidth of the protrusion electrodes. The protrusion body has a top portion with a round head and a bottom portion with a waist portion, smaller than the basewidth. It has been found that, the round head of the top portion and the waist portion of the bottom portion can improve the efficiency of the optical transmissivity of the liquid crystal layer as well the contrast between the bright state and the dark state of the display.

Claims

1. A liquid crystal display comprising:

a first substrate;

a second substrate;

a liquid crystal layer disposed between the first substrate and the second substrate,

a plurality of first protrusion electrodes and a plurality of second protrusion electrodes alternately arranged on the second substrate such that each of the plurality of first protrusion electrodes is adjacent to but spaced from at least one of the plurality of second protrusion electrodes, wherein each of the plurality of first protrusion electrodes and the plurality of second protrusion electrodes comprises a protrusion body, the protrusion body having a cross-sectional area comprising a flat side adjacent to the second substrate, a round side opposing the flat side, and a body section between the flat side and the round side, such that the body section is bound by the round side, the flat side, a first area side and a second area side, the flat side having a basewidth, wherein the first area side and the second area side are separated by a varied distance, the varied distance having a shortest distance defining a waist of the body section, the waist smaller than the basewidth; and

a voltage source electrically coupled to the plurality of first protrusion electrodes and the plurality of second protrusion electrodes, the voltage source arranged to provide a voltage potential between a first protrusion electrode and an adjacent second protrusion electrode, such that

the liquid crystal layer is configured in a first optical state in a case the voltage potential is provided between the first protrusion electrodes and the second protrusion electrodes, and the liquid crystal layer is configured in a second optical state in a case the first protrusion electrodes are electrically coupled to the second protrusion electrodes, wherein the body section comprises a top portion and a bottom portion adjoining the top portion, the top portion having the round side, the bottom portion having the flat side, the first area side and the second area side, and wherein

the top portion has an arcuate edge and a flat edge adjoining the arcuate edge, the flat edge having a flat edge length, and

the bottom portion is bound by an upper edge, a lower edge, a first side edge and a second side edge, the first side edge defining the first area side, the second side edge defining the second area side, the upper edge parallel to the lower edge, the upper edge having an upper edge length equal to the flat edge length, the lower edge having a lower edge length equal to the basewidth of the flat side, and wherein the waist is also smaller than the upper edge length, wherein

the arcuate edge and the flat edge of the top portion define a first angle at a joining point of the arcuate edge and the flat edge, and

the upper edge and the first side edge of the bottom portion define a second angle at a joining point of the upper edge and the first side edge, a sum of the first angle and the second angle having an angle range between 90 and 180 degrees, and wherein the bottom portion has a portion height separating the upper edge and the lower edge, and the bottom portion comprises a first trapezoid and a second trapezoid adjoining the first trapezoid, wherein

the first trapezoid is bound by a first side, a second side, a third side and a fourth side, the first side parallel to and separated by a first height from the second side, the first side having a first side length equal to the basewidth, the second side having a second side length equal to the waist of the body section, and

the second trapezoid is bound by a fifth side, a sixth side, a seventh side and an eighth side, the fifth side parallel to and separated by a second height from the sixth side, the fifth side having a fifth side length equal to the second side length of the first trapezoid, the sixth side having a sixth side length equal to the upper edge length of the bottom portion, and wherein

the third side and the seventh side define the first side edge of the bottom portion;

the fourth side and the eighth side define the second side edge of the bottom portion;

the second angle is defined at a joining point of the sixth side and the seventh side of the second trapezoid; and

a sum of the first height and the second height is equal to the portion height, and wherein

the sixth side length is smaller than, equal to, or greater than the first side length, and

the first height is smaller than, equal to, or greater than the second height.

2. The liquid crystal display according to claim 1, wherein the arcuate edge of the top portion is a section of a circle defined by a radius of curvature, the arcuate edge having a first length and the flat edge of the top portion having a second length, and wherein

a ratio of the first length to the radius of curvature is greater than 0 but smaller than or equal to 2π

, and

a ratio of the second length to the radius of curvature is greater than 0 but smaller than or equal to 2.

3. The liquid crystal display according to claim 1, wherein the arcuate edge of the top portion is a section of a parabolic arc.

4. The liquid crystal display according to claim 1, wherein the protrusion body has a surface and an electrically conductive layer provided on at least part of the surface, and wherein the voltage source is electrically coupled to the electrically conductive layer to provide the voltage potential.

5. The liquid crystal display according to claim 1, wherein the plurality of first protrusion electrodes and the plurality of second protrusion electrodes are made of an electrically conductive material.

6. A liquid crystal display comprising:

a first substrate;

a second substrate;

a liquid crystal layer disposed between the first substrate and the second substrate,

a plurality of first protrusion electrodes and a plurality of second protrusion electrodes alternately arranged on the second substrate such that each of the plurality of first protrusion electrodes is adjacent to but spaced from at least one of the plurality of second protrusion electrodes, wherein each of the plurality of first protrusion electrodes and each of the plurality of second protrusion electrodes have an elongated body, the elongated body having a round top, a flat bottom located on the second substrate; and

a voltage source electrically coupled to the plurality of first protrusion electrodes and the plurality of second protrusion electrodes, the voltage source arranged to provide a voltage potential between a first protrusion electrode and an adjacent second protrusion electrode, such that

the liquid crystal layer is configured in a first optical state in a case the voltage potential is provided between the first protrusion electrodes and the second protrusion electrodes, and the liquid crystal layer is configured in a second optical state in a case the first protrusion electrodes are electrically coupled to the second protrusion electrodes, wherein the round top comprises an elongated curved edge and the elongated body comprises a protrusion body with a varied width located between the elongated curved edge and the flat bottom, the protrusion body having a cross-sectional area comprising a flat side adjacent to the second substrate, a round side opposing the flat side, and a body section between the flat side and the round side, such that the body section is bound by the round side, the flat side, a first area side and a second area side, the flat side having a basewidth, wherein the first area side and the second area side are separated by a varied distance, the varied distance having a shortest distance defining a waist of the body section, the waist smaller than the basewidth, and wherein the body section comprises a top portion and a bottom portion adjoining the top portion, the top portion has an arcuate edge and a flat edge adjoining the arcuate edge, the flat edge having a flat edge length, and the bottom portion is bound by an upper edge, a lower edge, a first side edge and a second side edge, the first side edge defining the first area side, the second side edge defining the second area side, the upper edge parallel to the lower edge, the upper edge having an upper edge length equal to the flat edge length, the lower edge having a lower edge length equal to the basewidth of the flat side, and wherein the waist is also smaller than the upper edge length, wherein

the arcuate edge and the flat edge of the top portion define a first angle at a joining point of the arcuate edge and the flat edge, and

the upper edge and the first side edge of the bottom portion define a second angle at a joining point of the upper edge and the first side edge, a sum of the first angle and the second angle having an angle range between 90 and 180 degrees, and wherein the bottom portion has a portion height separating the upper edge and the lower edge, and the bottom portion comprises a first trapezoid and a second trapezoid adjoining the first trapezoid, wherein

the first trapezoid is bound by a first side, a second side, a third side and a fourth side, the first side parallel to and separated by a first height from the second side, the first side having a first side length equal to the basewidth, the second side having a second side length equal to the waist of the body section, and

the second trapezoid is bound by a fifth side, a sixth side, a seventh side and an eighth side, the fifth side parallel to and separated by a second height from the sixth side, the fifth side having a fifth side length equal to the second side length of the first trapezoid, the sixth side having a sixth side length equal to the upper edge length of the bottom portion, and wherein

the third side and the seventh side define the first side edge of the bottom portion;

the fourth side and the eighth side define the second side edge of the bottom portion;

the second angle is defined at a joining point of the sixth side and the seventh side of the second trapezoid; and

a sum of the first height and the second height is equal to the portion height, and wherein

the sixth side length is smaller than, equal to, or greater than the first side length, and

the first height is smaller than, equal to, or greater than the second height.

7. The liquid crystal display according to claim 6, wherein the first end of the protrusion body and the elongated curved edge define an angle at the joining line, the angle having an angle range between 90 and 180 degrees.

8. The liquid crystal display according to claim 6, wherein the elongated body has a surface and an electrically conductive layer provided on at least part of the surface, and wherein the voltage source is electrically coupled to the electrically conductive layer to provide the voltage potential.

9. The liquid crystal display according to claim 6, wherein the elongated body is made of an electrically conductive material.