Liquid crystal display with microlenses between interdigital electrodes and method

• US 5,844,644 A
• Filed: 07/22/1997
• Issued: 12/01/1998
• Est. Priority Date: 10/09/1996
• Status: Expired due to Term

• Current Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Oh, Young-Jin, Lim, Kyoung-Nam, Kim, Jeong-Hyun, Gu, Dong-Hyo
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Parker, Kenneth
• Application Number:
  US08/898,579
• Time in Patent Office: 497 Days
• Field of Search: 349/95, 349/44, 349/110, 349/111, 349/141
• US Class Current: 349/95
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/133565 inside the LC elements, i.e. between the cell substrates
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]

Abstract

A liquid crystal display with in-plane switching mode for improving its light transmittance, includes a first substrate that forms light transmissive portions and light untransmissive portions, a second substrate, and liquid crystal injected between the first and second substrates. The second substrate includes a black matrix, a color filter layer, an overcoat layer and an alignment film. The overcoat layer is patterned to form micro-lenses for refracting the incident light to pass through the light transmissive portions without being blocked by the light untransmissive portions. Various patterning methods can be selected to form the micro-lenses.

Claims

1. A liquid crystal display device comprising:

a first substrate including pixel electrodes, counter electodes, and regions between the pixel electrodes, and counter electrodes, the pixel and counter electrodes including light transmissive portions, the regions including light transmissive portions;

a second substrate;

a liquid crystal between the first and second substrates and

a focusing layer formed on the second substrate for focusing a light passing through the focusing layer onto said light transmissive portions and away from said light untransmissive portions.

2. A device as claimed in claim 1, wherein the index of refraction of the focusing layer is not less than 1.4.

3. A device as claimed in claim 1, wherein the focusing layer includes micro-lenses which are convex towards the first substrate.

4. A device as claimed in claim 1, wherein the focusing layer includes micro-lenses which are concave towards the first substrate.

5. A device as claimed in claim 1, wherein the light directed to said light untransmissive portions of the first substrate is refracted and passes through said light transmissive portions of the first substrate.

6. A device as claimed in claim 1, wherein device has an in-plane switching mode.

7. A device as claimed in claim 1, wherein the focusing layer includes micro-lenses formed on the second substrate.

8. A device as claimed in claim 7, wherein the micro-lenses are connected to each other.

9. A device as claimed in claim 7, further comprising:

an alignment layer formed on the micro-lenses.

10. A device as claimed in claim 9, wherein the refractive index of the focusing layer is greater than that of the alignment layer.

11. A device as claimed in claim 10, wherein the micro-lenses are convex towards the first substrate.

12. A device as claimed in claim 9, wherein the refractive index of the focusing layer is less than that of the alignment layer.

13. A device as claimed in claim 12, wherein the micro-lenses are concave towards the first substrate.

14. A device as claimed in claim 9, further comprising:

a black matrix formed on the second substrate; and

a color filter layer formed between the micro-lenses and the second substrate.

15. A device as claimed claim 9, further comprising:

an insulation film formed on the counter electrodes and under the pixel electrodes;

source bus lines formed on the insulation film; and

another alignment film formed on the insulation film.

23. A device as claimed in claim 7, wherein at least one of the pixel electrodes and counter electrodes corresponds to portions of two of the micro-lenses.

24. A device as claimed in claim 7, wherein at least one of the micro-lenses corresponds to at least one light transmissive portion, a portion of one pixel electrode, and a portion of one counter electrode.

16. A method of operating a liquid crystal display device including a first substrate having pixel electrodes, counter electrodes, and regions between the pixel electrodes and counter electrodes;

a second substrate; and

a liquid crystal between the first and second substrates, wherein the pixel and counter electrodes include light untransmissive portions and the regions include light transmissive portions, the method comprising the steps of;

generating a light using a light source set behind the second substrate; and

focusing the light passing tough the second substrate onto said light transmissive portions of the first substrate and away from said light untransmissive portions.

17. A method as claimed in claim 16, wherein said focusing step includes the step of:

passing the light through micro-lenses on the second substrate.

18. A method as claimed in claim 17, wherein in said passing steps, the refractive index of the micro-lenses is greater than that of the alignment layer.

19. A method as claimed in claim 17, wherein in said passing step, the micro-lenses are convex towards the first substrate.

20. A method as claimed in claim 17, wherein in said passing steps, the refractive index of the micro-lenses is less than that of the alignment layer.

21. A method as claimed in claim 17, wherein in said passing step, the micro-lenses are concave towards the first substrate.

22. A method as claimed in claim 16, wherein said focusing step includes the step of:

refracting the light approaching said light untransmissive portions of the first substrate so that the refracted light passes through said light transmissive portions of the first substrate.

25. A method as claimed in claim 17, wherein in said passing step, at least one of the pixel electrodes and counter electrodes corresponds to portions of two of the micro-lenses.

26. A method as claimed in claim 17, wherein in said passing step, at least one of the micro-lenses corresponds to at least one light transmissive portion, a portion of one pixel electrode, and a portion of one counter electrode.

27. A method as claimed in claim 17, wherein said focusing step further includes the step of:

passing the light through an alignment layer formed on the micro-lenses.