KR20080072976A - Dual display apparatus - Google Patents

Abstract

A dual display device is provided to improve the transmittance by applying an RGBW pixel structure to a transflective display panel, thereby improving the brightness of the display device. A display panel comprises an array substrate having color filters, a counter substrate facing the array substrate, and a liquid crystal layer interposed between the array substrate and the counter substrate. The array substrate includes a plurality of gat lines(GL), a plurality of data lines(DL), thin film transistors(TFT), pixel electrodes, and color filters, which are formed above a first base substrate. The color filters are formed in pixels(P) defined by the gate lines and the data lines, corresponding to respective sub-pixels of each of the pixels. Red, green, blue, and white sub-pixels include red, green, blue, white color filters, respectively. The counter substrate includes a common electrode formed above a second base substrate.

Description

Interactive display {DUAL DISPLAY APPARATUS}

1 is an exploded perspective view illustrating a bidirectional display device according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II ′ of FIG. 1.

3 is a plan view illustrating a portion of the display panel of FIG. 1.

4 is a cross-sectional view taken along line II-II ′ of FIG. 3.

5 is a cross-sectional view illustrating another embodiment of FIG. 4.

FIG. 6 is a cross-sectional view taken along line III-III ′ of FIG. 3.

7 is a cross-sectional view illustrating another embodiment of FIG. 6.

8A is a plan view schematically illustrating a pixel portion of a display panel according to a comparative example of the present invention.

8B is a plan view schematically illustrating a pixel portion of a display panel according to an exemplary embodiment of the present invention.

8C is a plan view illustrating another embodiment of FIG. 8B.

FIG. 8D is a plan view illustrating another embodiment of FIG. 8B.

FIG. 8E is a plan view showing another embodiment of FIG. 8B.

<Description of the symbols for the main parts of the drawings>

100: array substrate 200: counter substrate

400: display panel 500: light unit

700: bidirectional display

TE: Transmissive electrode RE: Reflective electrode

RP: Red subpixel GP: Green subpixel

BP: blue subpixel WP: white subpixel

The present invention relates to a bidirectional display device, and more particularly, to a bidirectional display device for improving brightness.

In general, the liquid crystal display is a flat panel display that displays an image by using the light transmittance of the liquid crystal, and is thinner and lighter than other display devices, and has a low driving voltage and low power consumption. Is being used.

The liquid crystal display may include a light unit having a light emitting diode for generating light and a light guide plate for guiding and emitting light from the light emitting diode, and a display panel for displaying an RGB color image by using light from the light unit. . Recently, in order to realize high brightness of the liquid crystal display, the light emission efficiency from the light unit may be improved by optimizing the light guide plate design and further combining the optical sheet.

On the other hand, liquid crystal displays generally display images in only one direction, but recently, two-way liquid crystal displays have been developed that display the same or different images in both directions, instead of displaying images in only one direction. It has been.

The bidirectional liquid crystal display device has a twin type including two light units and two display panels, a two way type including one light unit and two display panels, and one light unit and transmission There is a transflective type including a display panel divided into an area and a reflective area.

In this case, the transflective type bidirectional display device needs to display an image in both directions using light from one light unit, and thus may be weak in terms of luminance. In particular, since the light emitted from the light unit is absorbed while passing through the liquid crystal, the polarizing plate, the color filter of the display panel, and the like, the bidirectional liquid crystal display has a limitation in realizing a high brightness image.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a bidirectional display device capable of improving the brightness by changing the structure of the display panel.

In order to realize the above object of the present invention, a bidirectional display device according to an exemplary embodiment is divided into a transmission area and a reflection area to display an image in both directions, and includes a red subpixel, a green subpixel, a blue subpixel, and a white subpixel. And a light unit disposed on one side of the display panel to supply light to the display panel.

According to such a bidirectional display device, the brightness of the bidirectional display device can be improved by adding a white subpixel to the RGB unit pixels of the transflective display panel.

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

1 is an exploded perspective view illustrating a bidirectional display device according to an exemplary embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II ′ of FIG. 1.

1 and 2, the bidirectional display apparatus 700 according to an exemplary embodiment of the present invention displays a light unit 500 for supplying light and a display for displaying an image using light from the light unit 500. It includes a panel assembly.

The light unit 500 is disposed on one side of the display panel assembly to supply light to the display panel assembly. As in the exemplary embodiment of the present invention, the bidirectional display apparatus 700 may be formed in the front light unit 500 structure in which the light unit 500 is disposed above the display panel assembly. The light unit 500 may include a point light source 510 for generating light, and a light guide plate 520 disposed at one side of the point light source 510 to guide and emit light from the point light source 510. For example, the point light source 510 may be disposed in plurality on one side of the light guide plate 520 and may be a light emitting diode (LED) for generating white light.

In addition, the light unit 500 of the present embodiment may further include an optical sheet for improving light utilization efficiency. The optical sheet may include a diffusion sheet or a prism sheet for diffusing light emitted from the display panel assembly.

The display panel assembly includes a display panel 400 displaying images in both directions, a lower polarizing film 610 disposed below the display panel 400, and an upper polarizing film 620 disposed above the display panel 400. It includes.

The display panel 400 is disposed under the light unit 500 to display an image in both directions using light supplied from the light unit 500. As in the present exemplary embodiment, the display panel 400 is divided into a transmission area TA and a reflection area RA, and uses the light TL supplied from the light unit 500 and transmitted in the transmission area TA. The first image is displayed, and the second image is displayed using the light RL supplied from the light unit 500 and reflected from the reflection area RA.

The display panel 400 includes an array substrate 100, an opposing substrate 200 that opposes and couples the array substrate 100, and a liquid crystal layer 300 interposed between the array substrate 100 and the opposing substrate 200. Include. In the front light structure as in the present embodiment, one surface of the opposite substrate 200 faces the array substrate 100, and the other surface opposite to the one surface of the opposite substrate 200 faces the light unit 500. Can be.

In the array substrate 100, a signal line for dividing a plurality of pixel parts divided into a transmission area TA and a reflection area RA, a thin film transistor and a pixel electrode connected to the signal line, are formed, and on the opposite substrate 200, The common electrode is formed. As the arrangement of liquid crystal molecules of the liquid crystal layer 300 is changed by the electric field formed between the pixel electrode and the common electrode, and the light transmittance from the light unit 500 is changed, the display panel 400 displays an image of a desired gray scale. Can be displayed. A detailed description thereof will be described later with reference to FIG. 3.

The lower polarizing film 610 is disposed under the display panel 400. The lower polarizing film 610 includes a light transmission axis in a first direction to polarize the light TL transmitted from the display panel 400 in the first direction. The upper polarizing film 620 is disposed above the display panel 400 and the light unit 500. The upper polarizing film 620 includes a light transmission axis in a second direction to polarize the light RL reflected from the display panel 400 in the second direction. For example, the light transmission axis of the lower polarizing film 610 and the light transmission axis of the upper polarizing film 620 may be disposed perpendicular to each other.

The display panel 400 further includes a driving chip 410 for driving the display panel 400. The driving chip 410 generates a driving signal for driving the display panel 400 in response to various control signals applied from the outside. For example, the driving chip 410 may be mounted on the array substrate 100 through a chip on glass (COG) process.

3 is a plan view illustrating a portion of the display panel of FIG. 1. 4 is a cross-sectional view taken along line II-II ′ of FIG. 3. 5 is a cross-sectional view illustrating another embodiment of FIG. 4.

3 and 4, the display panel 400 includes an array substrate 100, a counter substrate 200, and a liquid crystal layer 300 interposed between the array substrate 100 and the counter substrate 200. .

In detail, the array substrate 100 includes a transparent first base substrate 110, a plurality of gate lines GL, a plurality of data lines DL, and a thin film transistor formed on the first base substrate 110. TFT) and pixel electrode 150.

The gate lines GL extend in a first direction, and the data lines DL extend in a second direction crossing the gate lines GL. A unit area defined by the gate lines GL and the data lines DL is partitioned on the array substrate 100. A pixel portion P having a plurality of subpixels is formed in the unit region, and each subpixel includes a thin film transistor TFT and a pixel electrode 150.

The thin film transistor TFT includes a gate electrode G, an active pattern (not shown), a source electrode S, and a drain electrode D. The thin film transistor TFT is applied to the gate lines GL and the data lines DL. It serves as a switching element for supplying an electrical signal to the pixel electrode 150.

The pixel electrode 150 includes a transmission electrode TE that transmits light and a reflection electrode RE that reflects light. For example, the transmissive electrode TE may be formed in the entire area of the subpixel so as to be connected to the thin film transistor TFT through the contact hole CNT. For example, the reflective electrode RE may be formed in a portion of the subpixel to be connected to the thin film transistor TFT through the contact hole CNT. As such, as the pixel electrode 150 includes the transmission electrode TE and the reflection electrode RE, each subpixel may be divided into a transmission area TA and a reflection area RA.

On the other hand, referring to Figure 4, as in an embodiment of the present invention, the counter substrate 200 is a transparent second base substrate 210, the light shielding pattern (BM) formed on the second base substrate 210, The color filter CF and the common electrode 220 may be included.

The light blocking pattern BM is formed corresponding to the gate lines GL, the data lines DL, and the thin film transistor TFT, and blocks light. The light blocking pattern BM may be formed of, for example, a black organic film material.

The color filter CF is partially overlapped with the light blocking pattern BM in a region defined by the light blocking pattern BM. That is, the color filter CF is formed to correspond to the pixel electrode 150 of each subpixel. As in this embodiment, the red subpixel RP includes a red color filter R_CF, the green subpixel GP includes a green color filter G_CF, and the blue subpixel BP is a blue color. The filter B_CF may be included, and the white subpixel WP may include a white color filter W_CF. Accordingly, each pixel unit P may implement a color to be expressed by mixing color light passing through the red, green, blue, and white color filters R_CF, G_CF, B_CF, and W_CF.

The common electrode 220 is formed on the color filter CF and the light blocking pattern BM to face the pixel electrode 150. The common electrode 220 is made of a transparent conductive material that can transmit light. For example, the common electrode 220 may be formed of indium zinc oxide (IZO) or indium tin oxide (ITO).

3 and 5, as in another embodiment of the present invention, the display panel 400 is coupled to face the array substrate 100 and the array substrate 100 on which the color filters CF are formed. The counter substrate 200 may include a liquid crystal layer 300 interposed between the array substrate 100 and the counter substrate 200.

Specifically, the array substrate 100 according to the present embodiment includes a first base substrate 110, a plurality of gate lines GL, a plurality of data lines DL, and a thin film formed on the first base substrate 110. The transistor TFT includes a pixel electrode 150 and a color filter CF. In the present embodiment, the rest of the components except for the arrangement of the color filter CF are the same as the above-described embodiment, and thus the detailed description thereof is omitted.

The color filter CF is formed in the pixel portion P region defined by the gate lines GL and the data lines DL. That is, the color filter CF is formed to correspond to each subpixel of the pixel portion P. FIG. As in this embodiment, the red subpixel RP includes a red color filter R_CF, the green subpixel GP includes a green color filter G_CF, and the blue subpixel BP is a blue color. The filter B_CF may be included, and the white subpixel WP may include a white color filter W_CF.

In this case, the counter substrate 200 may include a second base substrate 210 and a common electrode 220 formed on the second base substrate 210. As described above, as the color filter CF is formed on the array substrate 100, the light blocking pattern BM for forming the color filter CF corresponding to each sub-pixel is formed on the opposing substrate 200. It becomes unnecessary.

FIG. 6 is a cross-sectional view taken along line III-III ′ of FIG. 3. 7 is a cross-sectional view illustrating another embodiment of FIG. 6.

3 and 6, the display panel 400 includes an array substrate 100, an opposite substrate 200, and a liquid crystal layer 300. For reference, the display panel 400 according to the present exemplary embodiment has a color filter on array (COA) structure in which the color filter CF is formed on the array substrate 100. The array substrate 100 is formed on the first base substrate 110, the plurality of gate and data lines GL and DL, and a thin film transistor formed on the first base substrate 110 to define the pixel portion P. (TFT), pixel electrode 150 and color filter CF.

As in this embodiment, each pixel portion P includes red, green, blue, and white subpixels RP, GP, BP, WP, and each of the red, green, blue, and white subpixels RP. , GP, BP, and WP may include a transmission electrode TE and a reflection electrode RE. As a result, the display panel 400 transmits or reflects light for each subpixel to display an image in both directions.

6, specifically, each subpixel includes an array layer, a passivation layer 140, an organic pattern 142, a reflective electrode RE, a color filter CF, and a transmission electrode TE. The array layer forms a thin film transistor TFT and includes a gate electrode G, a gate insulating layer 120, an active pattern 130, a source electrode S, and a drain electrode D.

The gate electrode G extends from the gate line GL and constitutes a gate terminal of the thin film transistor TFT formed in each pixel portion P. As shown in FIG. For example, the gate electrode G may be formed of a single metal such as aluminum (AL), molybdenum (Mo), neodymium (Nd), or an alloy thereof.

The gate insulating layer 120 is formed on the first base substrate 110 on which the gate line GL is formed. The gate insulating layer 120 protects the gate line GL and insulates the gate line GL and the data line DL from each other. For example, the gate insulating layer 120 may be formed of silicon nitride (SiNx) and silicon oxide (SiOx).

The active pattern 130 is formed on the gate insulating layer 120 to overlap with the gate electrode G. The active pattern 130 includes an active layer 132 formed of amorphous silicon (a-Si) and an ohmic contact layer 134 formed of amorphous silicon (n + a-Si) doped with a high concentration of n + ions.

The source electrode S and the drain electrode D are formed on the gate insulating film 120. The source electrode S extends from the data line DL to form a source terminal of the thin film transistor TFT. The drain electrode D is formed to be spaced apart from the source electrode S to form a drain terminal of the thin film transistor TFT. The source electrode S and the drain electrode D are formed to be spaced apart from each other on the active pattern 130 to form a channel of the thin film transistor TFT. For example, the source electrode S and the drain electrode D may be formed of a single metal such as aluminum (AL), molybdenum (Mo), neodymium (Nd), or an alloy thereof.

The passivation layer 140 is formed on the first base substrate 110 on which the thin film transistor TFT is formed. The passivation layer 140 protects the thin film transistor TFT and insulates the thin film transistor TFT and the pixel electrode 150 from each other. The passivation layer 140 includes a first hole exposing one end of the drain electrode D of the thin film transistor TFT. For example, the passivation layer 140 may be formed of silicon nitride (SiNx) or silicon oxide (SiOx).

The organic pattern 142 is formed on the passivation layer 140 corresponding to the reflective region RA of each subpixel. The surface of the organic pattern 142 may have an uneven shape, for example, in order to increase the reflection efficiency of the reflective electrode RE. The organic pattern 142 may include a second hole exposing one end of the drain electrode D of the thin film transistor TFT to correspond to the first hole of the passivation layer 140. For example, the organic pattern 142 may be formed of a photosensitive organic material.

The reflective electrode RE is formed on the organic pattern 142 corresponding to the reflective region RA which is a part of the subpixel. The reflective electrode RE is in contact with one end of the drain electrode D exposed through the first hole of the passivation layer 140 and the second hole of the organic pattern 142 to be electrically connected to the thin film transistor TFT. Connected. The surface of the reflective electrode RE may have an uneven shape to increase reflection efficiency. The reflective electrode RE may be formed of a metal having good reflectivity, for example, silver (Ag), silver-molybdenum (Ag-Mo: AMO), or the like.

The reflective electrode RE may be directly formed on the passivation layer 140 of the reflective region RA. Alternatively, as in the present exemplary embodiment, a separate organic pattern 142 may be formed corresponding to the reflective region RA, and the reflective electrode RE may be formed on the organic pattern 142.

Because the bidirectional display device 700 according to the present invention displays an image in both directions using one light unit 500, it is difficult to implement a high brightness image in both directions. Accordingly, in the bidirectional display apparatus 700 having the front light structure in which the light unit 500 is disposed above the display panel 400, the organic pattern 142 is formed in the reflective region RA to form the reflective electrode RE. By forming a closer to the light unit 500, it is possible to improve the reflection efficiency of the reflected light.

The color filter CF is formed on the passivation film 140 corresponding to the reflective area RA and the transmission area TA. In detail, the color filter CF may be formed on the reflective electrode RE of the reflective region RA and may be formed on the passivation layer 140 of the transmissive region TA. The color filter CF may include a third hole exposing one end of the drain electrode D to correspond to the first and second holes.

As in an exemplary embodiment, the pixel portion P of the display panel 400 may include a red subpixel RP including a red color filter R_CF and a green subpixel including a green color filter G_CF. (GP), a blue subpixel BP including the blue color filter B_CF, and a white subpixel WP including the white color filter W_CF. For example, the white color filter (W_CF) may be formed of an organic film or a transparent photoresist material.

On the other hand, in the COA structure as in the present embodiment, the color filter CF of the reflective region RA may be formed between the reflective electrode RE and the liquid crystal layer 300. That is, the array substrate 100 has a structure in which the color filter CF is formed on the reflective electrode RE. Accordingly, the light RL reflected by the reflective electrode RE in the reflective region may pass through the liquid crystal layer 300 to implement a color image.

The transmissive electrode TE is formed on the color filter CF to correspond to the entire region of the subpixel including the reflective region RA and the transmissive region TA. The transmissive electrode TE is in contact with one end of the reflective electrode RE and the drain electrode D through the first, second and third holes, and is electrically connected to the thin film transistor TFT. The transmissive electrode TE is made of a transparent conductive material that can transmit light. For example, the transmissive electrode TE may be made of indium zinc oxide (IZO) or indium tin oxide (ITO).

3 and 7, the display panel of the bidirectional display device according to another embodiment of the present invention has the same configuration as that of the display panel of the bidirectional display device of the above-described embodiment except for the white subpixel. The description will be omitted, and the same reference numerals and names are used for the same components.

For example, the pixel portion P may include a red subpixel RP having a red color filter R_CF, a green subpixel GP having a green color filter G_CF, and a blue subpixel having a blue color filter B_CF. The pixel BP may be included, and the white subpixel WP may not include a separate color filter.

In detail, the white subpixel WP may include the array layer, the passivation layer 140, the reflective electrode RE, and the transparent electrode TE, which form the thin film transistor TFT. That is, since the white subpixel WP does not include a separate color filter CF, the reflective electrode RE and the transmissive electrode TE of the white subpixel WP are directly on the passivation layer 140. Can be formed in contact. Accordingly, the white subpixel WP may form a step vertically with other subpixels including the color filter CF.

This is because, in order to emit red, green and blue light using the white light generated from the light unit 500, the red subpixel RP is a red color filter R_CF, and the green subpixel GP is a green color filter G_CF. ), The blue sub-pixel BP needs to include an intermediate material called a blue color filter B_CF. On the contrary, in order to emit white light by using the white light generated from the light unit 500, the white subpixel WP includes a white color filter W_CF or, as in the present embodiment, separate intermediate materials are used. May not be included.

As such, the pixel portion P including the reflective area RA and the transmissive area TA of the transflective display panel 400 includes not only the red, green, and blue subpixels RP, GP, and BP, but also the white subpixel. By further including (WP), the luminance of the image displayed in both directions can be improved. Specifically, the light transmittance of the red, green, and blue subpixels (RP, GP, BP) is about 30%, and the light transmittance of the white subpixel (WP) is almost 100%. This is because the main components of the color filter CF are a photopolymerizable photosensitive composition and an RGB organic pigment, because predetermined light is absorbed from the organic pigment. Accordingly, as in the present invention, when the pixel portion P includes the RGB + W subpixel, the luminance may be improved by about 50% to 70% compared with the case where the pixel portion P includes the RGB subpixel.

8A is a plan view schematically illustrating a pixel portion of a display panel according to a comparative example of the present invention. 8B is a plan view schematically illustrating a pixel portion of a display panel according to an exemplary embodiment of the present invention.

For reference, embodiments in which the single pixel unit includes red, green, and blue subpixels are compared with embodiments of the present invention. In this case, the total area of the pixel portion including the red, green, and blue subpixels is the same as the total area of the pixel portion including the red, green, blue, and white subpixels.

8A and 8B, as in this embodiment, a single pixel portion of the display panel 400 includes one red, green, blue, and white subpixels RP, GP, BP, and WP, and is white. The area of the subpixel WP may be the same as the area of the red, green, and blue subpixels RP, GP, and BP. In addition, the red, green, blue, and white sub-pixels RP, GP, BP, and WP constituting the single pixel unit may be arranged in a row, that is, sequentially. For example, the pixel unit may have a long rectangular shape in the direction of the data lines DL.

In detail, the white subpixel WP may be formed on one side of the remaining subpixels in the direction of the data lines DL. In order to drive each sub-pixel in such a structure, the number of data lines DL is increased by 4/3 from 6 to 8, and the number of gate lines GL is maintained the same.

As in the present embodiment, as the number of data lines DL increases, the area occupied by the data lines DL in the pixel portion area becomes wider, and the area of each subpixel becomes smaller. Accordingly, although the overall aperture ratio of the pixel portion is reduced, the luminance of the display image can be improved as the pixel portion includes the white subpixel WP.

8C is a plan view illustrating another embodiment of FIG. 8B.

8A and 8C, for example, a single pixel portion includes a plurality of red, green, blue, and white subpixels RP, GP, BP, and WP, and the area of the white subpixel WP is red. It may be formed smaller than the area of the green and blue subpixels RP, GP, and BP. For example, an area of each of the red and green subpixels RP and GP may be formed to be equal to the sum of the area of the blue subpixel BP and the area of the white subpixel WP.

Specifically, the red subpixel RP is formed to face in the first diagonal direction in the pixel portion region, and the green subpixel GP is in the second diagonal direction crossing the first diagonal direction in the pixel portion region. The blue and white subpixels BP and WP may be formed to face each other, and may be formed between the red subpixel RP and the green subpixel GP. In order to drive each sub-pixel in such a structure, the number of data lines DL is reduced from 6 to 3 1/2, and the number of gate lines GL is maintained the same.

As in the present embodiment, as the number of data lines DL is reduced, the area occupied by the data lines DL in the pixel portion area becomes narrower, and the area of each subpixel becomes larger. As a result, the overall aperture ratio of the pixel portion is increased. In addition, as the pixel unit includes the white subpixel WP, the luminance of the display image may be improved.

FIG. 8D is a plan view illustrating another embodiment of FIG. 8B.

8A and 8D, for example, a single pixel portion includes red, green, blue and white subpixels RP, GP, BP, and WP, and the area of the white subpixel WP is red and green. And the same area as that of the blue subpixels RP, GP, and BP. For example, the subpixels may be arranged in two columns in the pixel portion region, and the pixel portion may have a long rectangular shape in the direction of the gate lines GL.

In detail, the red, green, blue, and white subpixels RP, GP, BP, and WP may be disposed in a clockwise direction within the pixel area. In order to drive each sub-pixel in such a structure, the number of data lines DL is reduced by 2/3 from 3 to 2, and the number of gate lines GL is doubled from 1 to 2. do.

As in this embodiment, the number of data lines DL is reduced, but as the number of gate lines GL is increased, the sum of the respective subpixels remains the same. Accordingly, the overall aperture ratio of the pixel portion remains the same, but as the pixel portion includes the white subpixel WP, the luminance of the display image may be further improved.

FIG. 8E is a plan view showing another embodiment of FIG. 8B.

8D and 8E, for example, the single pixel portion includes red, green, blue and white subpixels RP, GP, BP, and WP, and the area of the white subpixel WP is red and green. And smaller than the area of the blue subpixels RP, GP, and BP. For example, the subpixels may be arranged in two columns in the pixel portion region, and the pixel portion may have a square shape.

In detail, the red, green, blue, and white sub-pixels RP, GP, BP, and WP are disposed in a clockwise direction within the pixel portion area, and the arrangement order thereof may be changed. For example, the blue and red subpixels BP and RP may be formed in the vertical direction on the left side of the pixel portion, and the green and white subpixels GP and WP may be formed in the vertical direction on the right side of the pixel portion. In this case, the pixel portion is accurately divided into left and right directions so that the entire area of the blue and red subpixels BP and RP is the same as the entire area of the green and white subpixels GP and WP.

As in this embodiment, in one pixel portion including four sub-pixels, by adjusting the width between the data and the gate lines DL and GL, by adjusting the horizontal and vertical spacing of each sub-pixel, The area of the white subpixel WP may be smaller than the area of the remaining subpixels.

For example, an area of the red subpixel RP may be equal to an area of the blue subpixel BP, and an area of the white subpixel WP may be larger than that of the blue subpixel BP. That is, the area of each subpixel of the pixel portion may be formed to have a correlation of green subpixel GP> red subpixel RP = blue subpixel BP> white subpixel WP. In contrast, the areas of the red, green, and blue subpixels RP, GP, and BP are substantially the same, and the white subpixel WP may be formed to have an area of about 25% or less of the entire pixel portion. As described above, since the white subpixel WP is formed to have a smaller area than the red, green, and blue subpixels RP, GP, and BP, it is possible to prevent deterioration of the pure color of the color image.

As described above, in the bidirectional display device using one light unit and one transflective display panel, an RGBW pixel structure is applied to the transflective display panel to transmit 100% of the light to the added white subpixel. have. Accordingly, the overall light transmission efficiency of the transflective display panel can be improved by about 50% to 70% compared to the RGB pixel structure, and the brightness of the bidirectional display device can be improved.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (10)

A display panel divided into a transmissive region and a reflective region to display an image in both directions, and including a pixel unit having a red subpixel, a green subpixel, a blue subpixel, and a white subpixel; And And a light unit disposed on one side of the display panel to supply light to the display panel. The display panel of claim 1, wherein the display panel A base substrate, gate wirings formed in one direction on the base substrate, data wirings defining unit regions crossing the gate wirings, a thin film transistor connected to the gate and the data wirings, and the thin film transistor; An array substrate having connected pixel electrodes; An opposite substrate coupled to the array substrate and having a common electrode formed on one surface of the array substrate facing the pixel electrode; And And a liquid crystal layer interposed between the array substrate and the opposing substrate. The bidirectional display device of claim 2, wherein the red, green, blue, and white subpixels are formed in each unit region. 4. The bidirectional display device of claim 3, wherein the red, green, and blue subpixels comprise red, green, and blue color filters, respectively. The bidirectional display device according to claim 4, wherein the white subpixel comprises a white color filter. The bidirectional display device of claim 5, wherein the white color filter comprises an organic film or a transparent photoresist. 6. The bidirectional display device according to claim 5, wherein the red, green, blue, and white color filters are formed on the array substrate corresponding to the red, green, blue, and white subpixels. 6. The bidirectional display device according to claim 5, wherein the red, green, blue, and white color filters are formed on the counter substrate corresponding to the red, green, blue, and white subpixels. The bidirectional display device of claim 1, wherein an area ratio of the red, green, blue, and white subpixels is 1: 1: 1: 1. The bidirectional display device of claim 1, wherein an area of the white subpixel is smaller than an area of the red, green, and blue subpixels.

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