KR100608890B1 - Liquid Crystal Display Panel And Liquid Crystal Display Device Including the same - Google Patents

Abstract

The present invention relates to a liquid crystal display panel and a liquid crystal display device having the same.

According to an exemplary embodiment of the present invention, a liquid crystal display panel includes: the first substrate; A selective reflection film formed to have a different thickness on the first substrate to selectively transmit only light having a specific wavelength among light emitted from the outside, and to reflect light having a different wavelength; A second substrate, liquid crystal injected between the first and second substrates, and a black matrix partially formed on the second substrate; A thin film transistor is formed on any one of the first and second substrates.

Description

Liquid crystal display panel and liquid crystal display device having the same {Liquid Crystal Display Panel And Liquid Crystal Display Device Including the same}             

1 is a view showing a conventional liquid crystal display device.

2 is a view showing a conventional liquid crystal display panel in detail.

3 is a diagram illustrating a liquid crystal display according to a first embodiment of the present invention.

4 is a view illustrating in detail the liquid crystal display panel of FIG. 3.

5 is a view showing transmittance for each wavelength.

6 is a diagram illustrating each color transmittance for each thickness.

7 is a diagram illustrating a liquid crystal display according to a second exemplary embodiment of the present invention.

8 is a diagram illustrating a liquid crystal display according to a third exemplary embodiment of the present invention.

FIG. 9 is a cross-sectional view taken along line VII-VII ′ of FIG. 8.

10 is a view showing a liquid crystal display according to a fourth embodiment of the present invention.

11A and 11B illustrate examples of a backlight unit according to various embodiments of the present disclosure.

<Description of Symbols for Main Parts of Drawings>

2, 102, 202, 302, 402: liquid crystal display panels 8, 18: polarizing sheet

150, 250, 350, 450: selective reflection film

101, 201, 301, 401: backlight unit

The present invention relates to a liquid crystal display panel and a liquid crystal display device having the same, and more particularly, to a liquid crystal display panel capable of realizing high luminance and a liquid crystal display device having the same.

In general, liquid crystal displays (hereinafter referred to as "LCDs") have tended to be increasingly wider in application due to features such as light weight, thinness, and low power consumption. According to this trend, LCDs are used for office automation equipment, audio / video equipment, and the like. On the other hand, the LCD is controlled to display the desired image on the screen by adjusting the transmission amount of the light beam according to the image signal applied to the plurality of control switches arranged in a matrix form.

Since the LCD is not a self-luminous display device, a light source such as a back light is required. Such LCD backlight has a direct type and an edge type. In the edge type system, a lamp is installed outside the flat plate, and light is incident from the lamp onto the entire surface of the liquid crystal display panel using a transparent light guide plate. The direct type places several lamps on the plane. A diffusion plate is provided between the lamp and the liquid crystal display panel to maintain a constant space between the liquid crystal display panel and the lamp. Cold Cathode Fluorescent Lamp ("CCFL") method that supplies power by inserting electrodes at both ends of the glass tube of the lamp, and external electrode that supplies power to the electrode part that surrounds both ends of the glass tube of the lamp with metal material Fluorescent lamp (External Electrode Fluorescent Lighting: "EEFL") is a method.

1 and 2 show a conventional LCD.

1 and 2, a conventional LCD includes a liquid crystal display panel 2 for displaying an image and a backlight unit 1 for irradiating uniform light onto the liquid crystal display panel 2.

In the liquid crystal display panel 2, liquid crystal cells are arranged in an active matrix between upper and lower substrates, and pixel electrodes and a common electrode for applying an electric field to each of the liquid crystal cells are provided. Each of these pixel electrodes is connected to a thin film transistor used as a switch element. The pixel electrode drives the liquid crystal cell along with the common electrode according to the data signal supplied through the thin film transistor to display an image corresponding to the video signal. Polarizing plates 8 and 18 having different polarization directions are disposed on the front and rear surfaces of the liquid crystal display panel 2.

The backlight unit 1 includes a case, a reflective sheet stacked on the front of the case, a plurality of lamps positioned on the reflective sheet, a diffuser plate and an optical sheet disposed on the plurality of lamps.

A conventional liquid crystal display having such a structure realizes an image by activating the color filter layer using the white light W irradiated from the backlight unit 1. Specifically, as illustrated in FIG. 2, the white light W irradiated from the backlight unit 1 is formed of the three-color color filters R, G, and R formed on the upper substrate through the lower substrate of the liquid crystal display panel 2. B) is reached. At this time, each of the color filters R, G, and B expresses a color by absorbing all the remaining colors except for one of its own colors, that is, R, G, and B. Accordingly, the efficiency of the light used to express the color of the white light (W) irradiated from the backlight unit (1) can only stay at about 1/3, causing a problem that the light efficiency is greatly reduced. Efforts have been made to provide a backlight unit having a high brightness in order to improve such light efficiency, in particular, light transmittance, but this is a burden on power consumption and other LCD module configurations.

Accordingly, it is an object of the present invention to provide a liquid crystal display panel capable of achieving high luminance and a liquid crystal display device having the same.

In order to achieve the above object, the liquid crystal display device according to an embodiment of the present invention and the first substrate; A selective reflection film formed to have a different thickness on the first substrate to selectively transmit only light having a specific wavelength among the light irradiated from the outside, and to reflect light having a different wavelength, and a second material disposed to face the first substrate; A second substrate, liquid crystal injected between the first and second substrates, and a black matrix partially formed on the second substrate; A thin film transistor is formed on any one of the first and second substrates.

The selective reflection film is a first semi-transmissive film formed on the substrate; And a medium formed on the first semi-permeable membrane to cause multiple interference of light, and a second semi-permeable membrane formed on the medium.

The intensity of incident light is I ₀ , the refractive index of the medium is n, R is the reflectance of the transflective film, the intensity of transmitted light is I, the angle of incident light is θ, T is the transmittance of the transflective film, and λ ₀ is the wavelength of light in vacuum. , F value is the half-width value of the incident wavelength, the thickness d of the medium

to be.

The refractive index of the medium is formed to be 1.8 or more.

The selective reflection film has a thickness ratio of the red pixel area, the green pixel area, and the blue pixel area in a range of 6.6 to 7.5: 5.6 to 6.5: 4.6 to 5.5.

A color filter is formed on the second substrate.

According to an exemplary embodiment of the present invention, a liquid crystal display panel includes: the first substrate; A selective reflection film formed to have a different thickness on the first substrate to selectively transmit only light having a specific wavelength among light emitted from the outside, and to reflect light having a different wavelength; A second substrate, liquid crystal injected between the first and second substrates, and a black matrix partially formed on the second substrate; A thin film transistor and a color filter formed on the second substrate are provided.

A common electrode is formed on any one of the first substrate and the selective reflection film.

According to an exemplary embodiment of the present invention, a liquid crystal display panel includes: the first substrate; A selective reflection film formed on the first substrate with a different thickness to selectively transmit only light having a specific wavelength among the light irradiated from the outside, and reflecting light having a different wavelength; any one of the first substrate and the selective reflection film; A black matrix formed on one, a color filter formed on the black matrix, a second substrate disposed to face the first substrate, a liquid crystal injected between the first and second substrates, and the second And a thin film transistor formed on the substrate.

A common electrode is formed on the first substrate.

The liquid crystal display according to the embodiment of the present invention is a liquid crystal display panel having a selective reflection film which is formed to have a different thickness to transmit only a specific color wavelength in the light irradiated from the outside and reflects the other color wavelengths, and the reflection from the selective reflection film And a backlight unit for irradiating light to the liquid crystal display panel while reflecting back the color wavelength.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

2 is a diagram illustrating a liquid crystal display according to a first embodiment of the present invention.

Referring to FIG. 2, the liquid crystal display according to the first exemplary embodiment of the present invention includes a backlight unit 101 for generating light and a liquid crystal display panel 102 for irradiating light from the backlight unit 101. do.

The backlight unit 101 receives power from an external power source and irradiates light onto the liquid crystal display panel 102, a case accommodating the lamp, and is installed between the lamp and the case to prevent leakage of light generated from the lamp. In addition, a reflecting plate to be diffused, and an optical member for advancing the light generated from the lamp toward the liquid crystal display panel 102 and improving the efficiency of light to irradiate the liquid crystal display panel 102.

The liquid crystal display panel 102 includes a color filter array substrate 81 and a thin film transistor array substrate 91 bonded together with a liquid crystal 86 interposed therebetween.

The liquid crystal 86 is rotated in response to an electric field applied to the liquid crystal 86 to adjust the amount of light transmitted through the thin film transistor array substrate 91.

The color filter array substrate 81 includes a black matrix 96, a color filter 82, and a common electrode 84 formed on the rear surface of the upper substrate 80a. The black matrix 96 is formed of an opaque material and absorbs light incident from adjacent cells, thereby preventing a decrease in contrast. In the color filter 82, color filter layers of red 82R, green 82G, and blue 82B colors are arranged in a stripe shape to transmit light of a specific wavelength band, thereby enabling color display.

The thin film transistor array substrate 91 is formed such that the data line 98 and the gate line 94 cross each other on the front surface of the lower substrate 80b, and a thin film transistor 90 is formed at the intersection thereof. do. The thin film transistor 90 includes a gate electrode connected to the gate line 94, a source electrode connected to the data line 98, and a drain electrode facing the source electrode with a channel interposed therebetween. The thin film transistor 90 is connected to the pixel electrode 92 through a contact hole penetrating through the drain electrode. The thin film transistor 90 selectively supplies the data signal from the data line 98 to the pixel electrode 92 in response to the gate signal from the gate line 94. In addition, the selective reflection film 150 that transmits only a specific wavelength is formed on the thin film transistor array substrate 91. Here, the selective reflection film 150 will be described in detail later with reference to FIG. 4.

The pixel electrode 92 is formed in a cell region divided by the data line 98 and the gate line 94 and is made of a transparent conductive material having high light transmittance. The pixel electrode 92 generates a potential difference from the common electrode 84 formed on the upper substrate 80a by the data signal supplied via the drain electrode. Due to this potential difference, the liquid crystal 86 located between the lower substrate 80b and the upper substrate 80a is rotated by dielectric anisotropy. Accordingly, the light supplied from the light source via the pixel electrode 92 is transmitted toward the upper substrate 80a.

Referring to FIG. 4, each of the color filters 82a, 82b, respectively formed on the upper color filter array substrate 81 of the lower thin film transistor array substrate 91 of the liquid crystal display panel 102 according to the first embodiment of the present invention; The selective reflection film 150 having a different thickness is formed in a region corresponding to 82c).

The selective reflection film 150 includes a plurality of first and second semi-transmissive films 152 and 156 that reflect a part of light irradiated from the outside using a metal such as Al or a dielectric material, and partially transmit the light. A medium 154 having a specific thickness and refractive index is provided between the first and second transflective films 152 and 156. The medium 154 having such a structure causes incident light to cause multiple interference. In addition, only light having a selected wavelength is transmitted by different thicknesses of the medium 154 disposed between the first and second transflective films 152 and 156, and light other than the light having the selected wavelength is transmitted to the backlight unit 101. ) To reflect and reuse. At this time, the intensity I of transmitted light satisfies Equation 1.

,

,

Where I ₀ is the intensity of the incident light, n is the refractive index of the medium, d is the thickness of the medium, R is the reflectance of the semi-transmissive film, θ is the angle of incident light (the advancing angle of light from the vertical), and λ ₀ is the vacuum The wavelength of light, T is the transmittance of the semi-transmissive layer, F is the full-width half-maximum (FWHM) value, which is the half-width of the incident wavelength, and determines the reflectance of the first and second semi-transmissive layers 152 and 156. .

The intensity of the transmitted light is represented as a graph of transmittance for each wavelength as shown in FIG. 5 according to the angle θ and the F value of the incident light. In this case, since the angle in the medium 154 needs to be small in order to reduce the angle θ dependency, it is preferable to increase the refractive index n of the medium 154, so that the refractive index of the medium 154 is 1.8. It is formed as above. Using Equation 1, if the thickness d of the medium 154 is designed to be a wavelength peak for each color by adjusting the thickness d of the medium 154, a result as shown in FIG. 6 is obtained. Can be. Referring to FIG. 6, the condition for each color is n = 2.3 when F = 8 (R = 0.5), and the thinning of the liquid crystal display panel 102 and each color have the longest red wavelength and the blue wavelength. In consideration of the characteristics of the shortest visible light, the thickness ratio of the medium 154 that transmits red: green: blue light is 6.6-7.5: 5.6-6.5: 4.5-5.5, preferably 7: 6. It is formed so that ratio of: 5. In addition, the reflectance of the semitransmissive film is preferably about 0.4 to 0.9.

The liquid crystal display panel 102 according to the first exemplary embodiment of the present invention having the structure as described above uses the selective reflection film 150 having the medium 154 having different thicknesses for the white light emitted from the backlight unit 101. After the light is separated by wavelength band of each color, only the light of a specific wavelength is transmitted and the light of the remaining wavelength is reflected and reused, thereby improving the light transmittance by about 3 times compared to the conventional light transmittance.

7 is a diagram illustrating a liquid crystal display according to a second exemplary embodiment of the present invention.

Referring to FIG. 7, a liquid crystal display according to a second exemplary embodiment of the present invention includes a liquid crystal display panel 202 from which a color filter for implementing an image is removed, and a backlight unit for irradiating light to the liquid crystal display panel 202. 201). Here, since the backlight unit 201 according to the second embodiment of the present invention has the same configuration and operation as the backlight unit 101 according to the first embodiment of the present invention, description thereof will be omitted.

The liquid crystal display panel 202 includes an upper array substrate 281 and a thin film transistor array substrate 291 bonded to each other with a liquid crystal 286 interposed therebetween. The thin film transistor array substrate 291 includes a thin film transistor 290 formed on the lower substrate 280b and a selective reflection film 250 formed on the thin film transistor 290. The selective reflection film 250 includes a first semi-transmissive film 252, a medium 254 having a different thickness d for each pixel region, and a second semi-transmissive film 256 formed on the medium 254. . Here, since the thin film transistor array substrate 291 according to the second embodiment of the present invention has the same configuration as the thin film transistor array substrate 191 according to the first embodiment of the present invention, description thereof will be omitted.

The upper array substrate 281 includes a black matrix 296 and a common electrode 284 formed on the rear surface of the upper substrate 280a. The black matrix 296 is formed of an opaque material and absorbs light incident from adjacent cells, thereby preventing a decrease in contrast. The common electrode 284 activates the liquid crystal 286 by applying a common voltage to form a data voltage and an electric field applied to a data line formed on the thin film transistor substrate.

In the liquid crystal display according to the second exemplary embodiment of the present invention having the structure as described above, three colors (RGB) are formed by using the selective reflection film 250 formed on the thin film transistor array substrate 291 to radiate the light emitted from the backlight unit 201. After dividing by), the upper array substrate 281 is irradiated to implement a color image. Specifically, the selective reflection film 250 formed on the thin film transistor array substrate 291 may transmit only light having a color wavelength corresponding to each subpixel RGB in a region corresponding to each subpixel RGB. Designed to realize the color without the provision of a separate color filter.

Meanwhile, the liquid crystal display panels 102 and 202 according to the first and second embodiments of the present invention form the selective reflection films 150 and 250 on the thin film transistors 90 and 190, and thus the thin film transistors 90 and 190. ) Defects may occur. Accordingly, the liquid crystal display according to the third exemplary embodiment of the present invention proposes a structure in which the thin film transistor and the selective reflection film are formed on different layers.

8 is a diagram illustrating a portion of a liquid crystal display panel according to a third exemplary embodiment of the present invention.

FIG. 9 is a cross-sectional view taken along the line VII-VII ′ of FIG. 8.

8 and 9, a liquid crystal display according to a third exemplary embodiment of the present invention includes a liquid crystal display panel 302 for implementing an image and a backlight unit 301 for irradiating light to the liquid crystal display panel 302. ). Here, the backlight unit 301 according to the third embodiment of the present invention has the same configuration and operation as the backlight unit 101 according to the first embodiment of the present invention, and description thereof will be omitted.

The liquid crystal display panel 302 includes a color filter on thin film transistor (COT) substrate 381 and a lower plate 391 opposing the COT substrate 381. Herein, the liquid crystal display according to the third exemplary embodiment may implement an image in the same manner as the COT not only in the COT structure but also in the thin film transistor on color filter (TOC) structure.

The COT substrate 381 includes a thin film transistor array including a gate line 302 and a data line 304, a thin film transistor 330, and a protective film 318 formed on the upper substrate 380a; Pixel electrodes (R, G, B) 334 and the black matrix 332 formed on the thin film transistor array, and pixel electrodes overlapping the color filters (R, G, B) with the planarization layer 352 interposed therebetween ( 322).

The gate line 302 and the data line 304 are formed on the substrate 381 so as to intersect with the gate insulating layer 312 therebetween to define the pixel area.

The thin film transistor 330 includes a gate electrode 306 connected to the gate line 302, a source electrode 308 connected to the data line 304, and a drain electrode 310 facing the source electrode 308. . The thin film transistor 330 is overlapped with the gate electrode 306 and the gate insulating layer 312 interposed therebetween to form an active layer 314, which forms a channel between the source electrode 308 and the drain electrode 310, and an active layer thereof. 314 and an ohmic contact layer 316 to reduce contact resistance between the source and drain electrodes 308 and 310.

The passivation layer 318 is formed on the gate insulating layer 312 to cover the thin film transistor 330 and the data line 304.

The R, G, and B color filters 334 are formed on the passivation layer 318 in a dot shape so as to be divided into pixel areas. In this case, the color filters 334 are formed to be spaced apart or partially overlapped so as not to overlap the gate line 302 and the data line 304.

The black matrix 332 is formed on the passivation layer 318 on which the color filter 334 is formed so as to span the adjacent color filter 334 along the gate line 302 and the data line 304, and the thin film transistor 330. It is formed to overlap. The black matrix 332 prevents light leakage between the color filters 334, external light reflection, and light leakage current due to exposure of the channel portion of the thin film transistor 330 to external light.

A planarization layer 352 made of an organic insulator is formed on the color filter 334 and the black matrix 332. The planarization layer 352 compensates the level difference between the color filter 334 and the black matrix 332 to provide a flat surface, and prevents impurities from the color filter 334 and the black matrix 332 from entering the liquid crystal. do.

The pixel electrode 322 is formed independently in each pixel area so as to overlap the color filter 334 on the planarization layer 352. The pixel electrode 322 is connected to the drain electrode 310 exposed through the contact hole 320 penetrating through the planarization layer 352, the color filter 334, and the passivation layer 318.

The lower plate 391 has a common electrode 384 formed on the entire lower substrate 380b, and a selective reflection film 350 is formed on the common electrode 384. Since the selective reflection film 350 formed on the lower substrate 380a has the same structure and shape as the selective reflection film 350 according to the first and second embodiments of the present invention, description thereof will be omitted. The common electrode 384 may be formed on the selective reflection film 350.

In the liquid crystal display panel 302 according to the third embodiment of the present invention having the structure as described above, the thin film transistor 330 and the selective reflection film 350 are formed on different layers to minimize defects of the thin film transistor 330. In addition, since the occurrence of off-current due to collision between the light irradiated from the backlight unit 301 and the thin film transistor 330 may be prevented, a stable image may be realized. In addition, the liquid crystal display panel 302 according to the third exemplary embodiment of the present invention uses the selective reflection film 350 having a medium 354 having a different thickness from the white light W emitted from the backlight unit 301. After separation by wavelength band of each color, only the light of a specific wavelength is transmitted, and the light of the remaining wavelength is reflected by the backlight unit 301 and reused so that the light transmittance can be improved by about 3 times compared to the conventional light transmittance. do.

10 is a view showing a liquid crystal display according to a fourth embodiment of the present invention.

Referring to FIG. 10, a liquid crystal display according to a fourth exemplary embodiment of the present invention includes a liquid crystal display panel 202 having a color filter for realizing an image, and a selective reflection film that partially transmits black matrix and white light formed on the same substrate. And a backlight unit 201 for irradiating light to the liquid crystal display panel 202. Here, since the backlight unit 401 according to the fourth embodiment of the present invention has the same configuration and operation as the backlight unit 101 according to the first embodiment of the present invention, description thereof will be omitted.

The liquid crystal display panel 202 includes an upper plate 481 and a lower plate 491 for bonding the liquid crystal 486 therebetween.

The selective reflection film 450 formed on the lower substrate 480b, the black matrix 496 formed on the selection substrate 450 or between the lower substrate 480b and the selective reflection film 450, and the color filter RGB. And a lower plate 491 provided with a thin film transistor 490 formed thereon. The selective reflection film 450 includes a first transflective film 452, a medium 454 having a thickness d different for each pixel region, and a second transflective film 456 formed on the medium 454. . Here, the selective reflection film 450 has the same structure as the selective reflection film according to another embodiment of the present invention, and description thereof will be omitted. The color filter RGB may be formed in a color region according to each thickness on the selective reflection film 450, and a common electrode to which a common voltage is applied may be formed on the lower substrate 480b. Here, the black matrix 496 may be formed between the lower substrate 480b and the selective reflection film 450.

The upper plate 481 is formed with a thin film transistor 490 and a signal line for applying a signal to the thin film transistor 490. Since the thin film transistor 490 and the signal line have the same structure as the thin film transistor 490 according to another embodiment of the present invention, description thereof will be omitted.

In the liquid crystal display panel 401 according to the fourth embodiment of the present invention having the structure as described above, the thin film transistor 490 is formed on the upper plate 481, thereby preventing malfunction of the thin film transistor 490 from incident light. In addition, since only the thin film transistor 490 is formed on the top plate 481, defects of the thin film transistor 490 can be prevented.

11A and 11B are diagrams illustrating a backlight unit according to each embodiment of the present invention. FIG. 11A illustrates a structure of a direct type backlight unit, and FIG. 11B illustrates a structure of an edge type backlight unit. By using the backlight unit, the light efficiency is improved by re-reflecting the light selectively reflected from the selective reflection film. Here, the liquid crystal display according to each exemplary embodiment of the present invention is not limited by the configuration of the backlight unit, and may include various types of backlight units capable of generating and supplying light. In addition, the liquid crystal display panel according to each embodiment of the present invention may further include a polarizing plate on the top and bottom.

As described above, the liquid crystal display panel and the liquid crystal display device having the same according to the embodiment of the present invention divides the light irradiated from the backlight unit into respective color wavelengths by using a selective reflection film to correspond to each color wavelength. Light efficiency can be improved by irradiating a filter. Accordingly, the liquid crystal display according to the exemplary embodiment of the present invention can achieve high luminance and reduce power consumption.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (11)

The first substrate; A selective reflection film formed on the first substrate with different thicknesses to selectively transmit only light having a specific wavelength among light emitted from the outside, and reflect light having a different wavelength; A second substrate disposed to face the first substrate, A liquid crystal injected between the first and second substrates, A black matrix partially formed on the second substrate; And a thin film transistor formed on one of the first and second substrates. The method of claim 1, The selective reflection film is A first transflective film formed on the substrate; A medium formed on the first semi-permeable membrane and causing multiple interference of light; And a second transflective film formed on the medium. The method of claim 2, The intensity of incident light is I ₀ , the refractive index of the medium is n, the reflectance of the transflective film is R, the intensity of transmitted light is I, the angle of incident light is θ, the transmittance of the transflective film is T, and the wavelength of light in vacuum is λ _0. If the half-width value of the incident wavelength is F, the thickness d of the medium

The liquid crystal display panel characterized in that. The method of claim 2, And a refractive index of the medium is about 1.8 or more. The method of claim 1, The selective reflection film is A liquid crystal display panel, wherein the thickness ratio of the red pixel area, the green pixel area, and the blue pixel area is in the range of 6.6 to 7.5: 5.6 to 6.5: 4.6 to 5.5. The method of claim 1, And a color filter formed on the second substrate. The first substrate; A selective reflection film formed on the first substrate with different thicknesses to selectively transmit only light having a specific wavelength among light emitted from the outside, and reflect light having a different wavelength; A second substrate disposed to face the first substrate, A liquid crystal injected between the first and second substrates, A black matrix partially formed on the second substrate; And a thin film transistor and a color filter formed on the second substrate. The method of claim 7, wherein And a common electrode formed on any one of the first substrate and the selective reflection film. The first substrate; A selective reflection film formed on the first substrate with different thicknesses to selectively transmit only light having a specific wavelength among light emitted from the outside, and reflect light having a different wavelength; A black matrix formed on any one of the first substrate and the selective reflection film; A color filter formed on the black matrix, A second substrate disposed to face the first substrate, A liquid crystal injected between the first and second substrates, And a thin film transistor formed on the second substrate. The method of claim 9, The liquid crystal display panel further comprises a common electrode formed on the first substrate. A liquid crystal display panel having a selective reflection film formed at different thicknesses to transmit only a specific color wavelength in light emitted from the outside and reflecting the other color wavelengths; And a backlight unit for reflecting back the color wavelength reflected from the selective reflection film and irradiating light to the liquid crystal display panel.

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