KR20110037195A - Liquid crystal display - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to increase optical conversion efficiency by equipping a blue light source and to increase contrast ratio by controlling white balance. CONSTITUTION: A light source(250) supplies blue light. A first substrate(210) includes a thin film transistor and is located on the light source. A second substrate includes a red color conversion layer, a green color conversion layer, and a blue color conversion layer. A liquid crystal layer(230) is arranged between the first substrate and the second substrate. The red color conversion layer, the green color conversion layer, and the blue color conversion layer are included in the first substrate.

Description

Liquid Crystal Display

The present invention relates to a liquid crystal display device, and to a liquid crystal display device including a blue light source and a color conversion layer.

Recently, with the development of various portable electronic devices such as mobile phones, PDAs, and notebook computers, the demand for light and thin flat panel display devices can be gradually increased. Liquid crystal display (LCD), plasma display panel (PDP), organic light emitting diode (OLED), etc. are being actively researched as such flat panel display devices. BACKGROUND ART Liquid crystal display devices, which are easy to drive and easily implement high image quality, have been in the spotlight.

The liquid crystal display device includes a first substrate including a light source, a thin film transistor, and a pixel electrode connected to the thin film transistor, a second substrate facing the first substrate, and a second substrate including a red, green, and blue color filter; It may be composed of a liquid crystal layer positioned between the two substrates.

Accordingly, the liquid crystal arrangement of the liquid crystal layer changes according to the on / off operation of the thin film transistor, and light emitted from the light source passes through the liquid crystal layer to display red, green, and blue colors through a color filter, thereby realizing full color.

However, conventionally, since white light supplied from a light source implements color through a color filter having a low transmittance, there is a problem of many light losses. In order to solve this problem, the color conversion layer that can replace the color filter has been introduced to improve the efficiency of white light, but there are still limitations in providing a liquid crystal display device having excellent color reproduction and light efficiency.

Accordingly, the present invention provides a liquid crystal display device capable of improving color gamut and light efficiency.

In order to achieve the above object, a liquid crystal display device according to an embodiment of the present invention is a light source for supplying blue light, positioned on the light source, facing the first substrate including a thin film transistor and the first substrate The second substrate may include a red color conversion layer, a green color conversion layer, and a blue transmission layer.

A liquid crystal layer may be further included between the first substrate and the second substrate.

The light source may be an LED or an OLED.

Blue light may be emitted through the blue transmission layer.

At least one of the red color conversion layer, the green color conversion layer, and the blue transmission layer may have a larger area than the other.

In addition, a liquid crystal display according to an exemplary embodiment of the present invention may include a light source for supplying blue light, a first substrate positioned on the light source, and including a thin film transistor, opposing the first substrate, and a red color filter layer and green. The second substrate including the color filter layer and the blue color filter layer, and the first substrate or the second substrate may include a red color conversion layer, a green color conversion layer, and a blue color conversion layer.

The red color conversion layer, the green color conversion layer, and the blue color conversion layer may be located in the red color filter layer, the green color filter layer, and the blue color filter layer, respectively.

The red color conversion layer, the green color conversion layer and the blue color conversion layer are located on one surface of the first substrate facing the light source, and correspond to the red color filter layer, the green color filter layer, and the blue color filter layer, respectively. Can be located.

The light source may be an LED or an OLED.

As described above, the liquid crystal display of the present invention includes the blue light source and the color conversion layer, thereby improving the light conversion efficiency and reducing power consumption. In addition, due to the high color purity of the color conversion layer, there is an advantage that can implement a high quality image. In addition, by simultaneously providing the color conversion layer and the color filter, there is an advantage that the light conversion efficiency can be improved and the contrast ratio can be improved. In addition, there is an advantage that it is easy to adjust the white balance by varying the area of the color conversion layer, respectively.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a liquid crystal display device according to an exemplary embodiment of the present invention, FIG. 2 is a view showing a first substrate of FIG. 1, and FIGS. 3 and 4 are plan views showing a second substrate.

First, referring to FIG. 1, a liquid crystal display according to an exemplary embodiment of the present invention includes a first substrate 110 including a thin film transistor, a second substrate 120 facing the first substrate 110, and a gap between the first and second substrates 110. The liquid crystal panel 140 may include a liquid crystal layer 130, and a light source 150 disposed on the rear surface of the liquid crystal panel 140.

In the liquid crystal panel 140, the first substrate 110 is arranged so that the plurality of gate lines 112 and the plurality of data lines 114 cross each other, and the unit pixel region P is defined by the crossing. The defined pixel region P is formed in a matrix form. The pixel electrode 118 is formed in each pixel region P, and the thin film transistor 116 is formed at a point where each gate line 112 and the data line 114 cross each other.

The thin film transistor 116 is a switching element and transmits a data signal applied to the data line 114 to the pixel electrode 118 in response to the gate signal of the gate line 112.

The pixel electrode 118 may be made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), and may generate an electric field by switching the thin film transistor 116 to align the liquid crystal layer 130. Will be adjusted.

The liquid crystal layer 130 varies the alignment of liquid crystal molecules according to a vertical electric field between the first substrate 110 and the second substrate 120, or a horizontal electric field inside the first substrate 110. Various image information is displayed by changing the amount of light transmitted.

The liquid crystal layer 130 may operate by a twisted nemastic (TN) method, a vertical alignment (VA) method, an in-plane switching (IPS or Fringe Field Switching (FFS) method, etc.). have.

As illustrated, the second substrate 120 is formed to maintain a predetermined gap while facing the first substrate 110 with the liquid crystal layer 130 therebetween.

The light source 150 may be positioned on the rear surface of the first substrate 110. The light source 150 supplies light to the liquid crystal panel 140, and may be a light emitting diode (LED) or an organic light emitting diode (OLED), and may emit white or blue, but may be blue. have.

The light source 150 using such an LED or OLED is much more advantageous in color reproducibility and lifespan than CCFL. In particular, since it is possible to instantaneously turn on, there is an advantage in that it is possible to flash in synchronization with the scanning time of the liquid crystal display device.

Referring to FIG. 2, in the liquid crystal display according to the first exemplary embodiment, a red matrix R formed in a space between the black matrix 122 and the black matrix 122 in which the second substrate 120 is formed in a matrix form. The color conversion layer 123a, the green (G) color conversion layer 123b, and the blue (B) transmission layer 123c are included. In addition, an overcoat layer 124 may be further included on the red (R) color conversion layer 123a, the green (G) color conversion layer 123b, and the blue (B) transmissive layer 123c.

The black matrix 122 is formed at a designated position through an exposure process so as to selectively block an optical signal having a high possibility of distortion among optical signals transmitted through the first substrate 110.

The red (R) color conversion layer 123a, the green (G) color conversion layer 123b, and the blue (B) transmission layer 123c are disposed in the space between the black matrices 122 formed in a matrix form. The red (R) color conversion layer 123a, the green (G) color conversion layer 123b, and the blue (B) transmissive layer 123c or the other red (R) color conversion layer 123a and green ( G) The boundary region between the color conversion layer 123b and the blue (B) transmission layer 123c is formed to partially overlap the black matrix 122.

In this case, the red (R) color conversion layer 123a and the green (G) color conversion layer 123b may include phosphors for converting wavelengths of light incident from the light source, and may include a binder resin as necessary.

Here, the red (R) color conversion layer 123a for converting the blue light supplied from the light source into red is 4-dimethylaminomethylene-2-methyl-6- (p-dimethylaminostylyl) -4H-pyran. Cyanine-based dyes such as (DCM), Pyridine-based dyes such as 1-ethyl-2- (4- (p-dimethylaminophenyl) -1,3-butadienyl) -pyridinium perchlorate (pyridine), and rhoda Rhodamine-based pigments such as Min B, Rhodamine 6G, Basic Biored 11, or oxadine-based dyes.

In addition, the green (G) color conversion layer 123b for converting the blue light supplied from the light source into green has 2,3,5,6-1H, 4H-tetrahydro-8-tripromethylmethylinoridino (9, 9a, 1-gh) Coumarin (coumarin 153), 3- (2'-benzothiazolyl) -7-diethylaminocoumarin (coumarin 6), 3- (2'-benzimidazolyl) -7-N Coumarin pigments such as N-diethylaminocoumarin (coumarin 7), naphthalimide pigments such as basic yellow-51, solvent yellow-11, and solvent yellow-116, which are other coumarin pigment-based dyes.

The blue (B) transparent layer 123c is a transparent transparent layer without any color, and is formed of a colorless transparent resin or does not form any material.

The blue (B) transmission layer 123c may transmit blue light passing through the first substrate 110 and the liquid crystal layer 130 from the back side without loss, thereby increasing the luminance of blue. In addition, when no material is formed in the blue (B) transmissive layer 123c, a separate manufacturing process for forming the blue (B) transmissive layer 123c does not need to be performed, and thus the production process is simplified and manufactured. There is an advantage that can reduce the unit cost.

The overcoat layer 124 covers the red (R) color conversion layer 123a, the green (G) color conversion layer 123b, and the blue (B) transmissive layer 123c and serves to planarize these steps. The overcoat layer 124 is made of a transparent resin material or the like.

If the blue (B) transparent layer 123c is formed of a transparent resin, the blue (B) transparent layer 123c may be formed of the same material as the overcoat layer 124 through a single process. That is, the red (R) and green (G) color conversion layers 123a and 123b are formed, and then the blue (B) transmission layer 123c and the overcoat layer 124 using the constituent materials of the overcoat layer 124. To form a batch.

In addition, even if the blue (B) transparent layer 123c is formed of a separate transparent resin material different from the overcoat layer 124 or formed of the same transparent material as the overcoat layer 124, it is formed through a separate process. It can be natural.

In the red (R) color conversion layer 123a, the green (G) color conversion layer 123b, and the blue (B) transmissive layer 123c configured as described above, the red (R) color conversion layer 123a, The green (G) color conversion layer 123b and the blue (B) transmissive layer 123c form a subpixel, and each of the red (R) color conversion layer 123a, green (G) color conversion layer 123b, and blue (B) As shown in FIG. 3, the transmissive layer 123c forms one unit pixel Pb to display an image.

Meanwhile, referring to FIG. 4, among the red (R) color conversion layer 123a, the green (G) color conversion layer 123b, and the blue (B) transmission layer 123c formed on the second substrate 120, respectively. At least one may form an area wider than the other.

For example, if it is necessary to reduce the amount of light of red (R), the area of the red (R) color conversion layer 123a can be formed narrow, otherwise, if it is necessary to reduce the amount of light of green (G) green (G) The area of the color conversion layer 123b can be narrowly formed. On the other hand, if it is necessary to reduce the amount of light of blue (B), it is possible to form a narrow area of the blue (B) transparent layer 123c.

Therefore, there is an advantage that it is easy to adjust the white balance implemented in red (R), green (G) and blue (B).

As described above, the liquid crystal display according to the first exemplary embodiment of the present invention may include a blue light source and a color conversion layer having excellent light conversion efficiency, thereby improving light conversion efficiency compared to a white light source. In addition, there is an advantage that it is easy to adjust the white balance by adjusting the area of the color conversion layer or the transmission layer.

5 and 6 illustrate a liquid crystal display according to a second exemplary embodiment of the present invention. In the following, the description of the same configuration as in the first embodiment will be omitted.

Referring to FIG. 5, the liquid crystal display according to the second exemplary embodiment of the present invention includes a light source 250 for supplying blue light, a first substrate 210 positioned on the light source 250, and including a thin film transistor; A second substrate 220 and a second substrate 220 facing the first substrate 210 and including a red (R) color filter layer 223a, a green (G) color filter layer 223b, and a blue (B) color filter layer 224c. The first substrate 210 or the second substrate 220 may include a red (R) color conversion layer 224a, a green (G) color conversion layer 224b, and a blue (B) color conversion layer 224c. .

The first substrate 210 may include a thin film transistor and may include a pixel electrode connected to the thin film transistor as in the first embodiment.

The liquid crystal layer 230 varies the alignment of liquid crystal molecules according to a vertical electric field between the first substrate 210 and the second substrate 220, or a horizontal electric field inside the first substrate 210. Various image information is displayed by changing the amount of light transmitted.

As illustrated, the second substrate 220 is formed to maintain a predetermined gap while facing the first substrate 210 with the liquid crystal layer 230 therebetween.

The light source 250 may be positioned on the rear surface of the first substrate 210. The light source 250 is a liquid crystal panel 140 that supplies light, and may be a light emitting diode (LED) or an organic light emitting diode (OLED), and may emit white or blue, but may be blue. have.

Light sources using such LEDs or OLEDs are much more advantageous in terms of color reproduction and lifespan than CCFLs. In particular, since it is possible to instantaneously turn on, there is an advantage in that it is possible to flash in synchronization with the scanning time of the liquid crystal display device.

Unlike the first embodiment described above, the liquid crystal display according to the second exemplary embodiment of the present invention has a red (R) color filter layer 223a, a green (G) color filter layer 223b, and a second substrate 220. It may further include a blue (B) color filter layer 223c.

In more detail, the black matrix 222 formed in a matrix form, the red (R) color filter layer 223a, the green (G) color filter layer 223b, and the blue (B) color filter layer formed in the space between the black matrix 222. 223c.

The black matrix 222 is formed at a designated position through an exposure process so as to selectively block an optical signal having a high possibility of distortion among optical signals transmitted through the first substrate 210.

The red (R) color filter layer 223a, the green (G) color filter layer 223b, and the blue (B) color filter layer 223c are disposed in a space between the black matrices 222 formed in a matrix form. The red (R) color filter layer 223a, the green (G) color filter layer 223b, and the blue (B) color filter layer 223c or the other red (R) color filter layer 223a and the green (G) color. The boundary region between the filter layer 223b and the blue (B) color filter layers 223c is formed to partially overlap the black matrix 222.

In this case, the red (R) color filter layer 223a, the green (G) color filter layer 223b, and the blue (B) color filter layer 223c absorb part of the wavelength of light incident from the light source and transmit part of the light. An organic pigment or organic dye may be included and a binder resin may be included as needed.

Here, as the organic pigment or organic dye used for the red (R) color filter layer 223a, diketopyrrolopyrrole-based, anthraquinone-based, quinacridone-based, perylene-based, azo-based, benzimidazolone-based and the like can be used. have. An organic pigment or organic dye used for the green (G) color filter layer 223b may be a copper phthalocyanine halide, an anthraquinone series, or the like, and an organic pigment or a blue (B) color filter layer 223c. As the organic dye, copper phthalocyanine-based or indanthrone-based or the like can be used.

Meanwhile, the second substrate 220 is formed on the second substrate 220 on which the red (R) color filter layer 223a, the green (G) color filter layer 223b, and the blue (B) color filter layer 223c are formed. G) A color conversion layer 224a, a green (G) color conversion layer 224b and a blue (B) color conversion layer 224c may be further included.

More specifically, the red (G) color conversion layer 224a is located on the red (R) color filter layer 223a and the green (G) color conversion layer 224b is the green (G) color filter layer 223b. The blue (B) color conversion layer 224c may be correspondingly disposed on the blue (B) color filter layer 223c.

The red (G) color conversion layer 224a and the green (G) color conversion layer 224b may use the same material as the first embodiment described above. In addition, the blue (B) color conversion layer 224c is a stylbene type such as 1,4-bis (2-methylstyryl) benzene (Bis-MBS), trans-4,4'-diphenyl stylebene (DPS), and the like. Dye, coumarin type pigments, such as 7-hydroxy-4- methyl coumarin (coumarin 4), etc. can be used.

An overcoat layer 224 may be positioned on the red (G) color conversion layer 224a, the green (G) color conversion layer 224b, and the blue (B) color conversion layer 224c. The overcoat layer 224 covers the red (G) color conversion layer 224a, the green (G) color conversion layer 224b, and the blue (B) color conversion layer 224c, and serves to planarize their steps. The overcoat layer 224 is made of a transparent resin material or the like.

Meanwhile, referring to FIG. 6, the red (G) color conversion layer 224a, the green (G) color conversion layer 224b, and the blue (B) color conversion layer 224c may be formed on the first substrate 210. It may be located on one side.

More specifically, a red (R) color filter layer 223a, a green (G) color filter layer 223b, and a blue (B) color filter layer 223c on one surface of the first substrate 210 facing the light source 250. The red (G) color conversion layer 224a, the green (G) color conversion layer 224b, and the blue (B) color conversion layer 224c may correspond to each other.

Accordingly, in the liquid crystal display according to the second exemplary embodiment of the present invention, blue light emitted from the light source is converted into red light, green light and blue light through the color conversion layer, and the converted light is passed through the color filter layer. There is an advantage that the contrast ratio can be improved.

As described above, the liquid crystal display according to the exemplary embodiments of the present invention has a blue light source and a color conversion layer, thereby improving the light conversion efficiency and reducing power consumption. In addition, due to the high color purity of the color conversion layer, there is an advantage that can implement a high quality image. In addition, by simultaneously providing the color conversion layer and the color filter, there is an advantage that the light conversion efficiency can be improved and the contrast ratio can be improved. In addition, there is an advantage that it is easy to adjust the white balance by varying the area of the color conversion layer, respectively.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

1 is a view showing a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a view showing a first substrate of a liquid crystal display according to a first embodiment of the present invention.

3 and 4 are plan views illustrating a second substrate of the liquid crystal display according to the first embodiment of the present invention.

5 and 6 illustrate a liquid crystal display according to a second exemplary embodiment of the present invention.

Claims (9)

A light source for supplying blue light; A first substrate positioned on the light source and including a thin film transistor; And And a second substrate facing the first substrate, the second substrate including a red color conversion layer, a green color conversion layer, and a blue transmission layer. The method of claim 1, And a liquid crystal layer between the first substrate and the second substrate. The method of claim 1, The light source is a liquid crystal display device of LED or OLED. The method of claim 1, And a blue light emitted through the blue transparent layer. The method of claim 1, And at least one of the red color conversion layer, the green color conversion layer, and the blue transmission layer has a larger area than the other. A light source for supplying blue light; A first substrate positioned on the light source and including a thin film transistor; A second substrate facing the first substrate and including a red color filter layer, a green color filter layer, and a blue color filter layer; And And a red color conversion layer, a green color conversion layer, and a blue color conversion layer on the first substrate or the second substrate. The method of claim 6, And the red color conversion layer, the green color conversion layer, and the blue color conversion layer are located in the red color filter layer, the green color filter layer, and the blue color filter layer, respectively. The method of claim 6, The red color conversion layer, the green color conversion layer and the blue color conversion layer are located on one surface of the first substrate facing the light source, and correspond to the red color filter layer, the green color filter layer, and the blue color filter layer, respectively. Liquid crystal display device positioned so that. The method of claim 6, The light source is a liquid crystal display device of LED or OLED.

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