Color filter using surface plasmon, liquid crystal display device and method for fabricating the same

• US 8,330,904 B2
• Filed: 09/20/2010
• Issued: 12/11/2012
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Yoon, Min-Sung
• Primary Examiner(s): Vu, Phu
• Application Number:
  US12/886,317
• Publication Number:
  US 20110149214A1
• Time in Patent Office: 813 Days
• Field of Search: 349/106, 349/107
• US Class Current: 349/106
• CPC Class Codes: G02B 5/008 Surface plasmon devices diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553
• CPC Class Codes: G02B 5/201 in the form of arrays
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G02F 2201/121 common or background
• CPC Class Codes: G02F 2203/055 wavelength filtering
• CPC Class Codes: G02F 2203/10 plasmon
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters

Abstract

A color filter using a surface plasmon includes a metal layer; and a transmissive pattern formed in the metal layer, the transmissive pattern comprising a plurality of sub-wavelength holes having a period, wherein a desired color of light is output by selectively transmitting light of a specific wavelength by using the surface plasmon, and the plurality of sub-wavelength holes are arranged in a triangular lattice having a predetermined number of nearest neighboring holes with respect to a central hole.

Claims

1. A color filter using a surface plasmon, the color filter comprising:

a metal layer; and

a transmissive pattern formed in the metal layer, the transmissive pattern comprising a plurality of sub-wavelength holes having a period,

wherein a desired color of light is output by selectively transmitting light of a specific wavelength by using the surface plasmon, and

the plurality of sub-wavelength holes are arranged in a triangular lattice having a predetermined number of nearest neighboring holes with respect to a central hole.

2. The color filter of claim 1, wherein the central hole includes six neighboring holes having the same distance from the central hole of the transmissive pattern.

3. The color filter of claim 1, wherein a distance from the central hole of the transmissive pattern to a nearest neighboring hole is equal to a period, and a distance from the central hole to a next-nearest neighboring hole is about 1.732 times the period.

4. The color filter of claim 1, wherein a horizontal sectional surface of each of the plurality of sub-wavelength holes of the transmissive pattern has one of a circular shape, a quadrangular shape, a triangular shape, an oval shape, and a slit shape having an aspect ratio more than one.

5. The color filter of claim 1, wherein the metal layer is formed of a conductive material comprising at least one of aluminum (Al), gold (Au), silver (Ag), platinum (Pt), copper (Cu), nickel (Ni), palladium (Pd), zinc (Zn), iron (Fe), chrome (Cr), molybdenum (Mo), a doped semiconductor device, carbon nanotube, fullerene, conductive plastic, and electrical conductive composite material, or a mixture thereof.

6. The color filter of claim 1, wherein each of the plurality of sub-wavelength holes of the transmissive pattern has a size of about 50 nm to 10 μ

m.

7. The color filter of claim 1, wherein each of the plurality of sub-wavelength holes of the transmissive pattern has a period of about 50 nm to 500 nm.

8. The color filter of claim 1, wherein the transmissive pattern is divided into a plurality of regions having different periods.

9. A liquid crystal display (LCD) device, comprising:

a first substrate;

a second substrate;

a thin film transistor (TFT) formed on the first substrate, the TFT including a gate electrode, a semiconductor layer, a source electrode, and a drain electrode;

a pixel electrode connected to the drain electrode on the first substrate;

a common electrode formed on one of the first substrate and the second substrate; and

a color filter formed on one of the first substrate and the second substrate, and having a transmissive pattern formed in a metal layer, the transmissive pattern comprising a plurality of sub-wavelength holes having a period, wherein a desired color of light is output by selectively transmitting light of a specific wavelength by using a surface plasmon, and the plurality of sub-wavelength holes are arranged in a triangular lattice having a predetermined number of nearest neighboring holes with respect to a central hole.

10. The LCD device of claim 9, wherein the color filter is formed on the first substrate.

11. The LCD device, of claim 9, wherein the color filter is formed on the second substrate.

12. The LCD device of claim 9, further comprising:

an alignment layer on at least one of the first substrate and the second substrate; and

liquid crystal and a spacer between the first substrate and the second substrate.

13. The LCD device of claim 9, wherein the central hole includes six neighboring holes having the same distance from the central hole of the transmissive pattern.

14. The LCD device of claim 9, wherein a distance from the central hole of the transmissive pattern to a nearest neighboring hole is equal to a period, and a distance from the central hole to a next-nearest neighboring hole is about 1.732 times the period.

15. The LCD device of claim 9, wherein a horizontal sectional surface of each of the plurality of sub-wavelength holes of the transmissive pattern has one of a circular shape, a quadrangular shape, a triangular shape, an oval shape, and a slit shape having an aspect ratio more than one.

16. The LCD device of claim 9, wherein the metal layer is formed of a conductive material comprising at least one of aluminum (Al), gold (Au), silver (Ag), platinum (Pt), copper (Cu), nickel (Ni), palladium (Pd), zinc (Zn), iron (Fe), chrome (Cr), molybdenum (Mo), a doped semiconductor device, carbon nanotube, fullerene, conductive plastic, and electrical conductive composite material, or a mixture thereof.

17. The LCD device of claim 9, wherein each of the plurality of sub-wavelength holes of the transmissive pattern has a size of about 50 nm to 10 μ

m.

18. The LCD device of claim 9, wherein each of the plurality of sub-wavelength holes of the transmissive pattern has a period of about 50 nm to 500 nm.

19. The LCD device of claim 9, wherein the transmissive pattern is divided into a plurality of regions having different periods.

20. A liquid crystal display (LCD) device, comprising:

a first substrate;

a second substrate;

a thin film transistor (TFT) formed on the first substrate, the TFT including a gate electrode, a semiconductor layer, a source electrode, and a drain electrode;

a pixel electrode connected to the drain electrode on the first substrate;

a color filter formed on the second substrate, and having a transmissive pattern formed in a metal layer, the transmissive pattern comprising a plurality of sub-wavelength holes having a period, wherein a desired color of light is output by selectively transmitting light of a specific wavelength by using a surface plasmon, and the plurality of sub-wavelength holes are arranged in a triangular lattice having a predetermined number of nearest neighboring holes with respect to a central hole; and

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

wherein an electric field is generated between the pixel electrode on the first substrate and the color filter on the second substrate to drive the liquid crystal.

21. The LCD device of claim 20, wherein the color filter further functions as a common electrode to drive the liquid crystal with the pixel electrode.

22. The LCD device of claim 20, further comprising:

an alignment layer on at least one of the first substrate and the second substrate; and

liquid crystal and a spacer between the first substrate and the second substrate.

23. The LCD device of claim 20, wherein the central hole includes six neighboring holes having the same distance from the central hole of the transmissive pattern.

24. The LCD device of claim 20, wherein a distance from the central hole of the transmissive pattern to a nearest neighboring hole is equal to a period, and a distance from the central hole to a next-nearest neighboring hole is about 1.732 times the period.

25. A method for fabricating a liquid crystal display (LCD) device, the method comprising:

providing a first substrate and second substrate;

forming a thin film transistor (TFT) on the first substrate, the TFT including a gate electrode, a semiconductor layer, a source electrode, and a drain electrode;

forming a pixel electrode connected to the drain electrode on the first substrate;

forming a common electrode on one of the first substrate and the second substrate;

forming a color filter on one of the first substrate and the second substrate, the color filter having a transmissive pattern formed in a metal layer, the transmissive pattern comprising a plurality of sub-wavelength holes having a period, wherein a desired color of light is output by selectively transmitting light of a specific wavelength by using surface plasmon, and the plurality of sub-wavelength holes are arranged in a triangular lattice having a predetermined number of nearest neighboring holes with respect to a central hole; and

bonding the first and second substrates to each other.

26. The method of claim 25, wherein the color filter is formed on the first substrate.

27. The method claim 25, wherein the color filter is formed on the second substrate.

28. The method claim 25, further comprising:

forming an alignment layer on at least one of the first substrate and the second substrate; and

providing liquid crystal and a spacer between the first substrate and the second substrate.

29. The method of claim 25, wherein the central hole includes six neighboring holes having the same distance from the central hole of the transmissive pattern.

30. The method claim 25, wherein a distance from the central hole of the transmissive pattern to a nearest neighboring hole is equal to a period, and a distance from the central hole to a next-nearest neighboring hole is about 1.732 times the period.

31. The method of claim 25, wherein a horizontal sectional surface of each of the plurality of sub-wavelength holes of the transmissive pattern has one of a circular shape, a quadrangular shape, a triangular shape, an oval shape, and a slit shape having an aspect ratio more than one.

32. The method of claim 25, wherein the metal layer is formed of a conductive material including at least one of aluminum (Al), gold (Au), silver (Ag), platinum (Pt), copper (Cu), nickel (Ni), palladium (Pd), zinc (Zn), iron (Fe), chrome (Cr), molybdenum (Mo), a doped semiconductor device, carbon nanotube, fullerene, conductive plastic, and electrical conductive composite material, or a mixture thereof.

33. The method of claim 25, wherein each of the plurality of sub-wavelength holes of the transmissive pattern has a size of about 50 nm to 10 μ

m.

34. The method of claim 25, wherein each of the plurality of sub-wavelength holes of the transmissive pattern has a period of about 50 nm to 500 nm.

35. The method of claim 25, wherein the transmissive pattern is divided into a plurality of regions having different periods.

36. A method for fabricating a liquid crystal display (LCD) device, the method comprising:

providing a first substrate and a second substrate;

forming a thin film transistor (TFT) on the first substrate, the TFT including a gate electrode, a semiconductor layer, a source electrode, and a drain electrode;

forming a pixel electrode connected to the drain electrode on the first substrate;

forming a color filter on the second substrate, the color filter having a transmissive pattern formed in a metal layer, the transmissive pattern comprising a plurality of sub-wavelength holes having a period, wherein a desired color of light is output by selectively transmitting light of a specific wavelength by using the surface plasmon, and the plurality of sub-wavelength holes are arranged in a triangular lattice having a predetermined number of nearest neighboring holes with respect to a central hole;

forming an alignment layer and a spacer on at least one of the first substrate and the second substrate; and

providing a liquid crystal,

wherein an electric field is generated between the pixel electrode on the first substrate and the color filter on the second substrate to drive the liquid crystal.

37. The method of claim 36, wherein the color filter further functions as a common electrode to drive the liquid crystal with the pixel electrode.

38. The method of claim 36, wherein the central hole includes six neighboring holes having the same distance from the central hole of the transmissive pattern.

39. The method claim 36, wherein a distance from the central hole of the transmissive pattern to a nearest neighboring hole is equal to a period, and a distance from the central hole to a next-nearest neighboring hole is about 1.732 times the period.