KR100983519B1 - Liquid display device having touch screen - Google Patents

Abstract

A liquid crystal display device having a touch screen for improving the transmittance is disclosed. The first substrate of the liquid crystal display device with a touch screen includes a video display area and a video image display area adjacent to the video display area in a pixel for displaying an image, and includes a position sensing area for detecting a position of a contacted object. Is formed on the first substrate, and includes a color filter having a color pixel corresponding to the image display area, the liquid crystal is interposed between the first substrate and the second substrate, and the backlight assembly is formed below the first substrate. Light is provided to the first substrate and the second substrate. Therefore, since a separate transparent substrate for a touch screen is unnecessary as compared with the conventional one, transparency is improved and manufacturing cost is reduced.

Description

Liquid crystal display with built-in touch screen {LIQUID DISPLAY DEVICE HAVING TOUCH SCREEN}

1 is a schematic configuration diagram of a liquid crystal display device to which a touch screen is adhered according to an exemplary embodiment.

2 is a schematic configuration diagram of a liquid crystal display device to which a touch screen is adhered according to another exemplary embodiment.

3 is a schematic cross-sectional view of a liquid crystal display with a touch screen according to an embodiment of the present invention.

FIG. 4 is a layout diagram of unit pixels of the TFT substrate illustrated in FIG. 3.

5 is a cross-sectional view taken along line AA ′ of FIG. 4.

FIG. 6 is a cross-sectional view taken along line BB ′ of FIG. 4.

FIG. 7 is a layout diagram of the color filter substrate illustrated in FIG. 3.

FIG. 8 is a cross-sectional view taken along the line CC ′ of FIG. 7.

9 is a layout diagram of a TFT substrate according to another embodiment of the present invention.

10 is a layout diagram of a color filter substrate according to another exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

310: liquid crystal display panel 320: backlight assembly                 

330 TFT substrate 340 color filter substrate

350: liquid crystal 400: unit pixel

410: display area 420: location detection area

412,414,416: R, G, B subpixel 422: Sensor subpixel

450: liquid crystal drive TFT 470: sensor TFT

480: storage capacitor 490: switch TFT

The present invention relates to a liquid crystal display device with a built-in touch screen, and more particularly, to a liquid crystal display device with a touch screen for improving transmittance.

The touch screen is a state-of-the-art input device that replaces a keyboard and a mouse, and is a device in which a user touches a monitor using a hand or a touch pen to perform a desired task by mounting the touch screen on a monitor. Therefore, the touch screen is an ideal device capable of performing intuitive tasks under a GUI (Graphic User Interface) environment (Windows operating system). Accordingly, the touch screen can be widely used in computer-based training, simulation applications, office automation applications, education applications, and game applications.

Such a touch screen generates a photo current according to light reflected by an object to be contacted, for example, a finger or a touch pen, charges the generated charge and outputs a voltage according to the charged charge. As a result, the position of the contacted object is detected.

In general, since the touch screen is configured in the form of a thin film, it is used as it is mounted on the liquid crystal display panel.

As shown in FIG. 1, first, the touch screen 100 in the form of a thin film is bonded onto the transparent substrate 110. Thereafter, the transparent substrate 110 to which the touch screen 100 is adhered is adhered to the upper portion of the liquid crystal display panel 120. That is, the touch screen 100 is mounted on the liquid crystal display panel 120 as the transparent substrate 110 is adhered to the upper polarizing plate 130 of the liquid crystal display panel 120. Here, the lower polarizer 140 is formed under the liquid crystal display panel 120.

Meanwhile, as shown in FIG. 2, the touch screen 200 is attached to the liquid crystal display panel 210 as the touch screen 200 is adhered to the polarizing film 220 formed on the liquid crystal display panel 210. Here, the lower polarizer 230 is formed below the liquid crystal display panel 210, and the upper polarizer is not formed above.

As described above, since the touch screen according to the related art is adhered to a separate transparent substrate before being mounted on the liquid crystal display panel, the transmittance is reduced by the transparent substrate.

In addition, when the touch screen according to the related art is attached to the liquid crystal display panel in a form of being bonded to a polarizing film, the touch screen is also a thin film, and the polarizing film is a thin film, and thus the film is warped or bent. This causes ripple defects.

In addition, conventionally, there is a problem in that the parts cost increases as the liquid crystal display panel and the touch screen are separately manufactured, and the manufactured liquid crystal display panel and the touch screen panel are bonded together.

Accordingly, an object of the present invention is to provide a liquid crystal display device incorporating a touch screen for improving the transmittance.

The first substrate of the liquid crystal display device with a touch screen according to the present invention for achieving the above object is provided with a plurality of pixels for displaying an image, the plurality of pixels is formed in a matrix form, the image display in each pixel And a position sensing region formed adjacent to the region and the image display region and sensing a position of the contacted object, wherein the second substrate is formed on the first substrate and has a color pixel corresponding to the image display region. And a filter, wherein the liquid crystal is interposed between the first substrate and the second substrate, and the backlight assembly is formed under the first substrate to provide light to the first substrate and the second substrate.

Here, the image display area is formed corresponding to the color pixels of the color filter, and includes first to third image sub-pixels for driving the liquid crystal, and the position sensing area is formed in an area proximate the color filter and is in contact with the object. It includes a sensor sub-pixel for detecting the position of.                     

Therefore, the transmittance of the liquid crystal display device can be improved.

Hereinafter, a liquid crystal display device having a touch screen according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic cross-sectional view of a liquid crystal display with a touch screen according to an embodiment of the present invention.

As shown in FIG. 3, the liquid crystal display device 300 having a touch screen according to an embodiment of the present invention displays an image and detects a position of an object in contact with the liquid crystal display panel 310. And a backlight assembly 320 that provides light to the panel 310.

The liquid crystal display panel 310 includes a TFT substrate 330, a color filter substrate 340 provided to face the TFT substrate 330, and a liquid crystal 350 interposed between the two substrates.

The TFT substrate 330 will be described in more detail as follows.

4 is a layout diagram of unit pixels of the TFT substrate illustrated in FIG. 3, FIG. 5 is a cross-sectional view taken along line AA ′ of FIG. 4, and FIG. 6 is a cross-sectional view taken along line BB ′ of FIG. 4.

As shown in FIG. 4, the TFT substrate 330 includes a plurality of unit pixels 400 configured in a matrix form. Here, the unit pixel 400 is a display area 410 for displaying an image as colors are implemented in the liquid crystal display panel 310, and a position sensing area for detecting a position of an object in contact with the liquid crystal display panel 310 ( 420.

An R sub pixel 412, a G sub pixel 414, and a B sub pixel 416 are formed in the display area 410, and a sensor sub pixel is formed in the position sensing area 420. 422 is formed. That is, in the liquid crystal display device 300 according to the present invention, the unit pixel includes three image subpixels R, G, and B subpixels 412, 414, 416 for image display and one sensor subpixel 422 for position detection. Include.

Here, the R, G, and B subpixels 412, 414, 416 extend in the first direction and are arranged in the second direction with the plurality of data lines 430 spaced apart from each other to have a predetermined interval in a second direction perpendicular to the first direction. The plurality of gate lines 415 and 440 that extend and are spaced apart from each other to be spaced apart from each other in the first direction are formed at the intersection points. In this case, the R, G, and B subpixels 412, 414, 416 are sequentially arranged adjacent to each other.

In addition, the R, G, and B sub pixels 412, 414, 416 each include a liquid crystal driving TFT 450 for driving liquid crystal and a pixel electrode 460 connected to the liquid crystal driving TFT 450, respectively.

As shown in FIG. 4 and FIG. 5, the liquid crystal driving TFT 450 is a switching element for driving the liquid crystal 350, and includes a gate electrode 502 and a source electrode 503 formed on the first transparent substrate 501. ) And a drain electrode 504. In this case, the gate electrode 502 is insulated from the source electrode 503 and the drain electrode 504 through the gate insulating film 505. As power is applied to the gate electrode 502 on the gate insulating layer 505, an active pattern 506 for applying power to the drain electrode 504 from the source electrode 503 is formed, and a source is formed over the active pattern 506. Electrode 503 A drain electrode 504 is formed.

The organic insulating layer 508 is formed on the entire surface of the first transparent substrate 501 including the liquid crystal driving TFT 450, and partially exposes the drain electrode 504 of the liquid crystal driving TFT 450 on the organic insulating layer 508. The contact hole 509 is formed.

In addition, the pixel electrode 460 is formed to have a uniform thickness on the organic insulating layer 508 and is electrically connected to the drain electrode 504 through the contact hole 509.

Meanwhile, as shown in FIGS. 4 and 6, the sensor subpixel 422 is adjacent to the R, G, and B subpixels 412, 414, 416 and is defined by two adjacent data lines among the plurality of data lines. Is formed.

In addition, the sensor subpixels 412, 414, and 416 may include a sensor TFT 470 for generating photo current according to reflected light of an object in contact with the liquid crystal display panel 310, a storage capacitor 480 for charging electric charges according to the generated photo current, and And a switch TFT 490 for outputting a voltage according to the charge charged in the storage capacitor 480. At this time, since the data line 500 to which the switch TFT 490 is connected is used as a sensor signal output line (Readout) for outputting the sensed position detection signal to the outside, it will be referred to as a sensor signal output line hereinafter.

The gate electrode 472 of the sensor TFT 470 is connected to the gate line of the previous stage. That is, when the gate electrode 472 of the sensor TFT 470 is connected to the gate electrode 472 of the liquid crystal driving TFT 450 of the R, G, and B subpixels 412, 414, 416, the N-th gate line, It is connected to the N-1 th gate line 415.

Further, the drain electrode 474 of the sensor TFT 470 is connected to the gate electrode 472, and the source electrode 476 of the sensor TFT 470 and the source electrode 492 of the switch TFT 490 are the first electrode. And electrically connected via 480a. The drain electrode 494 of the switch TFT 490 is connected to the sensor signal output line 500.

The second electrode 480b is positioned with the first electrode 480a and the insulating layer 485 interposed therebetween, and the first electrode 480a and the second electrode 480b serve as a storage capacitor Cst 480. do. At this time, the storage capacitor 480 charges a charge in proportion to the amount of light input to the sensor TFT 470.

A first active pattern 478 made of amorphous silicon (a-Si) is formed between the source electrode 476 and the drain electrode 474 of the sensor TFT 470, and the source electrode 492 of the switch TFT 490 is formed. A second active pattern 496 made of amorphous silicon is formed between the drain electrode and the drain electrode 494. Here, when a predetermined amount or more of light is received by the first active pattern 478, the source electrode 476 and the drain electrode 474 of the sensor TFT 470 are electrically connected to each other.

Further, a gate insulating film 600 is formed on the gate electrode 472 of the sensor TFT 470 and the gate electrode 498 of the switch TFT 490 to insulate the source electrodes 476 and 492 and the drain electrodes 474 and 494 from each other. . A first black matrix 610 is formed on the drain electrode 494 and the source electrode 492 of the switch TFT 490 as a light shielding layer to prevent light from being received.

FIG. 7 is a layout view of the color filter substrate illustrated in FIG. 3, and FIG. 8 is a cross-sectional view taken along the line CC ′ of FIG. 7.

As shown in FIG. 7, the color filter substrate 340 is formed in a region corresponding to the R, G, and B sub-pixels 412, 414, 416 of the TFT substrate 330, and R where a predetermined color is expressed as light passes through. A color filter 740 formed of transparent pixels 730 adjacent to the G, B color pixels 700, 710 and 720, and the R, G and B color pixels 700, 710 and 720, and formed in an area corresponding to the sensor sub-pixel 422, A second black matrix 750 and a common electrode (not shown) are included to prevent light leakage between the pixels. At this time, the R, G, B color pixels 700, 710, 720 have the same arrangement structure as the R, G, B subpixels 412, 414, 416 of the TFT substrate 330, and are sequentially arranged adjacent to each other.

Here, the transparent pixels 730 of the color filter 740 are regions where R, G, and B color pixels are not formed. That is, as illustrated in FIG. 8, R, G, and B color pixels 700, 710, and 720 are respectively formed in the area A corresponding to the R, G, and B subpixels 412, 414, and 416, respectively. R, G, and B pixels 700, 710, and 720 are not formed in the corresponding region B, and only transparent common electrodes are formed. As such, since only the transparent common electrode is formed in the area corresponding to the sensor subpixel 422, the transmittance for detecting the position of the contacted object is almost 100%.

The operation of the liquid crystal display according to the present invention configured as described above is as follows.

First, a touch screen operation for recognizing a position of an object in contact with the liquid crystal display panel will be described.

When a user touches a finger or a touch pen to the color filter substrate 340 of the liquid crystal display panel 310, light generated from the backlight assembly 320 positioned under the TFT substrate 330 is transferred to the TFT substrate 330 and the liquid crystal. After passing through the 350, the light is incident on the color filter substrate 340. In this case, since the transparent pixel 730 in the region corresponding to the sensor subpixel 422 is not formed with the R, G, and B color pixels, the light incident on the color filter substrate 340 is applied to the finger or the touch pen. After being reflected, it is received by the first active pattern 478 of the sensor TFT 470.

As a result, the sensor TFT 490 becomes conductive so that the storage capacitor 480 is charged with a charge proportional to the amount of light input. The switch TFT 490 reads the amount of charge charged according to the light input to the storage capacitor 480, and outputs a voltage according to the read amount of charge, that is, a position sensing signal to the outside through the sensor signal output line 500.

In general, since the liquid crystal display device 300 has a low gate voltage for operating the liquid crystal driving TFT 450 most of the time, the sensor TFT 470 of the sensor subpixel 422 is reflected light during this period. Generates a photo current, the storage capacitor 480 charges the charge according to the photo current, and the switch TFT 490 as a high signal is applied to the gate line to which the gate electrode 498 of the switch TFT 490 is connected. Outputs a voltage according to the charge charged in the storage capacitor 480 through the sensor signal output line 500.

Next, during the display operation, as the liquid crystal driving TFT 450 of the R, G, and B subpixels 412, 414, 416 is operated, between the pixel electrode 460 of the TFT substrate 330 and the common electrode of the color filter substrate 340. As the electric field difference is generated and the liquid crystal 350 is tilted according to the generated electric field difference, the amount of light generated from the backlight assembly 320 and incident on the color filter substrate 340 is adjusted.

Therefore, the color filter 740 of the color filter substrate 340 expresses the R, G, and B colors by the R, G, and B color pixels 700, 710, and 720 according to the amount of incident light, and the expressed R, G, B colors. The predetermined color is displayed as the colors are mixed.

9 is a layout diagram of a TFT substrate according to another embodiment of the present invention, and FIG. 10 is a layout diagram of a color filter substrate according to another embodiment of the present invention.

First, a liquid crystal display device having a TFT substrate and a color filter substrate according to another embodiment of the present invention has the same structure as that of FIG. 3.

Referring to FIG. 9, a TFT substrate according to another embodiment of the present invention includes a plurality of unit pixels 900 configured in a matrix form. Here, the unit pixel 900 is a display area in which R, G, and B subpixels 910, 920, and 930 are formed to display an image as colors are implemented in the liquid crystal display panel, and detects a position of an object in contact with the liquid crystal display panel. The sensor subpixel 940 is formed of a position sensing region.

Here, two subpixels of the R, G, and B subpixels 910, 920, and 930 and the sensor subpixels 940 are arranged in the first column so as to be adjacent to each other, and the remaining two subpixels are arranged in the second column so as to be adjacent to each other. That is, the B subpixel 930 and the sensor subpixel 940 are arranged in the first column so as to be adjacent to each other, and the G subpixel 920 and the R subpixel 910 are arranged in the second column so as to be adjacent to each other.

The R, G, and B subpixels 910, 920, and 930 each include a liquid crystal driving TFT 950 and a pixel electrode 960. The liquid crystal driving TFT 950 and the pixel electrode 960 are the same as in the exemplary embodiment of the present invention. Since the structure, a detailed description thereof will be omitted.

In addition, the sensor subpixel 940 includes a sensor TFT 970, a storage capacitor 980, and a switch TFT 990. The sensor TFT 970, the storage capacitor 980, and the switch TFT 990 include the present invention. Since the embodiment has the same structure, a detailed description thereof will be omitted.

On the other hand, the color filter substrate according to another embodiment of the present invention is formed in the region corresponding to the R, G, B sub-pixels (910, 920, 930), as shown in Figure 10, a predetermined color is expressed as light passes Transparent pixels 1030 adjacent to the R, G, B color pixels 1000, 1010, 1020, and R, G, B color pixels 1000, 1010, 1020, and formed in an area corresponding to the sensor sub-pixel 940. ) Includes a color filter 1040, a black matrix 1050 to prevent light leakage between pixels, and a common electrode (not shown).

Here, the transparent pixel 1030 of the color filter 1040 is formed in a region corresponding to the sensor subpixel 940, and R, G, and B color pixels 1000, 1010, and 1020 are not generated, and the transparent common electrode is formed. Only is formed.

At this time, the R, G, B color pixels 1000, 1010, 1020 have the same arrangement structure as the R, G, B subpixels 910, 920, 930 of the TFT substrate, and the two color pixels are arranged in the first column so as to be adjacent to each other. The remaining color pixels are arranged in the second column, and a transparent region in which only the common electrode is formed is adjacent to the color pixels arranged in the second column.

The liquid crystal display according to another exemplary embodiment of the present invention configured as described above has the same operation as the exemplary embodiment of the present invention, and thus a detailed description thereof will be omitted.

As described above, the liquid crystal display device having the touch screen according to the present invention includes a display area for displaying an image in one pixel and a position detection area for detecting the position of an object to be contacted. Here, three image subpixels R, G, and B subpixels are formed in the display area, and one sensor subpixel is formed in the position sensing area.

Therefore, the present invention can reduce the manufacturing cost compared to the conventional manufacturing of the touch screen and the liquid crystal display panel separately by forming a sensor sub-pixel for detecting the position of the object in contact with the pixel when manufacturing the liquid crystal display panel for displaying an image. It can be effective.

In addition, since the present invention does not have a separate transparent substrate for the touch screen, since the light from the backlight assembly passes only through the liquid crystal display panel, there is an effect of improving the transmittance as compared to the conventional.

Although the present invention has been described with reference to the embodiments, those skilled in the art may variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. You will understand.

Claims (7)

A plurality of pixels for displaying an image, wherein the plurality of pixels are formed in a matrix form, each pixel is formed adjacent to the image display area and the image display area, the position detection for sensing the position of the contacted object A first substrate comprising a region; A second substrate formed on the first substrate; A liquid crystal interposed between the first substrate and the second substrate; And A backlight assembly formed under the first substrate to provide light to the first substrate and the second substrate, And the second substrate includes a transparent pixel that transmits light of the backlight assembly in response to a position sensing region of the first substrate. The display apparatus of claim 1, wherein the image display area is formed corresponding to a color pixel of a color filter, and includes first to third image subpixels for driving the liquid crystal, and the position sensing area is adjacent to the color filter. And a sensor sub-pixel formed in an area and sensing a position of the object to be contacted. The liquid crystal display device with a built-in touch screen of claim 2, wherein the first to third image subpixels and the sensor subpixels are sequentially arranged in a line to be adjacent to each other. 3. The method of claim 2, wherein two of the first to third image subpixels and the sensor subpixel are arranged in a first column to be adjacent to each other, and the remaining two subpixels are arranged in a second column to be adjacent to each other. A liquid crystal display device with a built-in touch screen. The touch screen of claim 2, wherein the first to third image subpixels each include a liquid crystal driving switching element for driving the liquid crystal and a pixel electrode electrically connected to the liquid crystal driving switching element. One liquid crystal display. The method of claim 2, wherein the sensor sub-pixel A sensor switching element for generating a photo current according to the reflected light from the contacted object; A storage capacitor charging a charge according to the generated photocurrent; And And an output switching device for outputting a position sensing signal according to the charged charge to the outside. 7. The plurality of gate lines of claim 6, wherein the sensor subpixels extend in a first direction and are spaced apart from each other in a second direction perpendicular to the first direction to be spaced apart from each other. And are formed in an area defined by two adjacent gate lines and data lines among the plurality of data lines arranged to be spaced apart from each other in the first direction at predetermined intervals. The output switching element is connected to an i-th gate line of the two adjacent gate lines, and the sensor switching element is connected to an i-1 th gate line, The output switching element is connected to any one of the two adjacent data lines, the data line connected to the output switching element is a liquid crystal display with a touch screen, characterized in that the output line for outputting the sensed position signal Device.

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