KR100995571B1 - Display device and display system - Google Patents

Abstract

A liquid crystal display device and a liquid crystal display system are disclosed. The liquid crystal display includes a light sensing element that recognizes the sensing light provided by the user and generates a position signal according to the position of the sensing light. The position signal generated by the light sensing element is provided to the information processing device connected to the liquid crystal display. When the sensing light is supplied to an optical sensing element built into the liquid crystal display panel, the liquid crystal display is not opened by opening a part of the color filter facing the photosensitive element or forming a color filter where the photosensitive element faces the photosensitive element. In addition to improving the luminance of the generated image, the optical recognition rate of the photosensitive device is greatly improved, thereby improving both the performance and the display quality of the liquid crystal display.

Description

Display and Display System {DISPLAY DEVICE AND DISPLAY SYSTEM}

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

FIG. 2 is a plan view conceptually illustrating a portion of the first substrate illustrated in FIG. 1.

3 is a cross-sectional view taken along the line A ₁ -A ₂ of FIG. ₂ .

4 is a plan view conceptually illustrating a second substrate illustrated in FIG. 1.

5 is an enlarged plan view illustrating the light sensing device of FIG. 4.

6 is a cross-sectional view conceptually illustrating a first electrode and a second electrode of the liquid crystal display according to the present invention.

7 is a plan view conceptually showing another embodiment of a liquid crystal display according to the present invention.

8 is a cross-sectional view conceptually showing another embodiment of a liquid crystal display according to the present invention.

9 is a conceptual diagram illustrating a liquid crystal display system according to an embodiment of the present invention.

10 is a conceptual diagram of a liquid crystal display system according to another embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device and a display system, and more particularly, to a display device and a display system in which the display quality is improved by greatly improving the optical recognition rate of a photosensitive device disposed between pixels.

In general, a display device converts an electrical signal applied from an information processing device into an image. Conventional display apparatuses and information processing apparatuses are only capable of one-way communication. Therefore, in order to display a new image from the display apparatus, a data input apparatus for inputting information into the information processing apparatus, for example, a keyboard, a keypad, a mouse, or the like is required.

Some of the recently developed display apparatuses have a function of reconstructing an image by directly inputting the image on a screen on which an image is displayed and outputting information to the information processing apparatus. In other words, this means that the bidirectional communication between the display device and the information processing device is enabled.

The conventional display device further includes a touch screen panel for bidirectional communication between the display device and the information processing device. The touch screen panel changes the pressure applied by the operator's hand or a touch pen into position data and outputs the position data to the information processing apparatus. The information processing apparatus processes the position data input from the display apparatus to output a new image signal to the display apparatus, and the display apparatus displays the new image corresponding to the image signal.

However, due to the touch panel, the display device has a problem in that thickness and weight are increased. In addition, a display device using a touch panel has a problem that is unsuitable for expressing precise characters or pictures.

Recently, a light sensing liquid crystal display device that detects light input by an operator to output a location information signal and communicates bidirectionally with an information processing device has been developed. Such a photosensitive liquid crystal display has a built-in photosensitive sensor that detects light and outputs a signal having position information together with pixels displaying an image.

The light sensor detects the light input by the operator and outputs a signal that can be recognized by the information processing device, and the output signal is transmitted to the information processing device. The information processing apparatus outputs a new image signal to the photosensitive liquid crystal display in response to the signal input from the photosensitive liquid crystal display, and the photosensitive liquid crystal display displays the new image by the image signal.

On the other hand, a light pen is required to apply light to a liquid crystal display having a pixel and a light sensing sensor. The light pen has a light source for generating high brightness light. A red light emitting diode having a high optical recognition rate is used as a light source of the light pen, and the light emitting diode is disposed at one end of the light pen facing the liquid crystal display.

However, in the conventional photosensitive liquid crystal display device, a considerable amount of light emitted from the light pen is lost while passing through the color filter and the organic layer protecting the pixels and the photosensitive sensors, and enter the photosensitive sensor. The amount of light entering is reduced. As a result, there is a problem in that the sensing sensitivity of the photosensitive sensors is lowered and the photosensitive liquid crystal display is malfunctioning.

In addition, since parts such as a light emitting diode and a power supply unit are built in the light pen for applying light to the light sensing unit, the production cost is increased, and the light pen has a weight and a volume. In addition, since the power supply unit for supplying power to the light emitting diode is a consumable part, there is a need to frequently replace the power supply unit.

Accordingly, the present invention has been made in view of such a conventional problem, and a first object of the present invention is to provide a display device in which malfunction is prevented by increasing the recognition rate of light inputted on the display panel by light.

It is a second object of the present invention to provide a display system for converting image light generated in the display device into sensing light using a light pen to input information into a liquid crystal display device.

In order to realize the first object of the present invention, the present invention includes a first light transmission region for filtering white light and emitting red, green and blue light, respectively, and a second light transmission region for transmitting white light. An optical sensing device disposed on the first substrate, the first pixel region formed corresponding to the first light transmission region, the second pixel region formed corresponding to the second light transmission region, and the second pixel region to output a sensing signal by sensing light; A second substrate including an element, a liquid crystal layer interposed between the first substrate and the second substrate, a first electrode and an electric field disposed in the first and second pixel regions to control the liquid crystal contained in the liquid crystal layer To provide a display device including a second electrode spaced apart from the first electrode.

In addition, in order to realize the second object of the present invention, the present invention includes a first light transmission region for filtering white light and emitting red, green and blue light, respectively, and a second light transmission region for transmitting white light. An optical sensing device disposed on the first substrate, the first pixel region formed corresponding to the first light transmission region, the second pixel region formed corresponding to the second light transmission region, and the second pixel region to output a sensing signal by sensing light; A second substrate including an element, a liquid crystal layer interposed between the first substrate and the second substrate, a first electrode and an electric field disposed in the first and second pixel regions to control the liquid crystal contained in the liquid crystal layer The liquid crystal display device includes a second electrode spaced apart from the first electrode, and a light including a light converter configured to convert red, green, blue light and white light emitted from the first substrate into sensing light. It provides a display system comprising a.

According to the present invention, the optical recognition rate of the optical sensing element which is embedded in the display device and transmits the information input by the user to the information processing device is further improved to improve the quality of the display device.

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

Display

1 is a partial cutaway perspective view of a liquid crystal display according to an exemplary embodiment of the present invention. FIG. 2 is a plan view conceptually illustrating a portion of the first substrate illustrated in FIG. 1. 3 is a cross-sectional view taken along the line A ₁ -A ₂ of FIG. ₂ .

Referring to FIG. 1, the liquid crystal display device 800 includes a first substrate 100, a second substrate 200, a liquid crystal layer 300, and first and second electrodes (not shown).

Referring to FIG. 2, the first substrate 100 includes a transparent glass substrate. The first substrate 100 includes a first effective display area 110 and a first non-effective display area 120. The first invalid display area 120 surrounds the first effective display area 110.

A black matrix 130 is disposed in the first effective display area 110. The black matrix 130 has a lattice shape. The black matrix 130 is formed by patterning a chromium thin film, a chromium oxide film, a black organic film, or the like formed on the first substrate 100.

2 and 3, in order to display a full-color image, the red light RL, the green light GL, and the blue light filtered from the openings of the black matrix 130 are filtered from the white light WL. BL) is emitted.

To implement this, a red color filter 142, a green color filter 144, and a blue color filter 146 are disposed in the opening of the black matrix 130. Hereinafter, a region through which the red color filter 142, the green color filter 144, and the blue color filter 146 pass will be referred to as a first light transmission region 150.                     

Meanwhile, the transparent pattern 148 is disposed in the opening of the black matrix 130 to improve the brightness of the image emitted from the first effective display area 110. The transparent pattern 148 passes white light WL as it is. Hereinafter, the region through which the transparent pattern 148 passes will be referred to as a second light transmission region 160.

The first and second light transmitting regions 150 and 160 are disposed in a matrix form on the first effective display region 110. The first light transmission region 150 displays a color image, and the second light transmission region 160 increases the luminance of the color image.

4 is a plan view conceptually illustrating a second substrate illustrated in FIG. 1.

Referring to FIG. 4, the second substrate 200 includes a transparent glass substrate. The second substrate 200 includes a second effective display area 210 and a second non-effective display area 220. The second invalid display area 220 surrounds the second effective display area 210.

The second substrate 200 is disposed to face the first substrate 100. In the present embodiment, the first effective display area 110 faces the second effective display area 210 and the second invalid display area 120 faces the second invalid display area 220.

The second effective display area 210 of the second substrate 200 includes a first pixel region 250 and a second pixel region 260. The first pixel region 250 faces the first light transmission region 150, and the second pixel region 260 faces the second light transmission region 160.                     

The first pixel region 250 and the second pixel region 260 of the second substrate 200 may include a first driving signal line 233 for driving the first thin film transistor 230 and the first thin film transistor 230; The second driving signal line 235 is included.

The first thin film transistor 230 includes a first gate electrode G1, a first source electrode S1, a first channel layer C1, and a first drain electrode D1. The first gate electrode G1 is insulated from the first channel layer C1 and changes the electrical characteristics of the first channel layer C1 from a nonconductor to a conductor. The first source electrode S1 and the first drain electrode D1 are electrically connected to the first channel layer C1.

The first driving signal line 233 is connected to the first gate electrode G1, and the second driving signal line 235 is connected to the first source electrode S1. The first driving signal line 233 applies a first driving voltage to the first gate electrode G1. The second driving signal line 235 applies a second driving voltage to the first source electrode S1.

In operation, the second driving voltage is applied to the first source electrode S1 through the second driving signal line 235. Subsequently, a first driving voltage is applied to the first gate electrode G1 through the first driving signal line 233, so that electrical characteristics of the first channel layer C1 are changed from a non-conductor to a conductor. Therefore, the second driving voltage is output to the first drain electrode D1 through the first channel layer C1.

5 is an enlarged plan view illustrating the light sensing device of FIG. 4.

4 and 5, the second pixel region 260 facing the transparent pattern 148 of the first substrate 100 of the second substrate 200 includes a photosensitive device 270. The light sensing element 270 recognizes light, for example, red light RL, green light GL, blue light BL, or white light WL, and outputs a light sensing signal including position data.

The photosensitive device 270 includes a second thin film transistor 272, a third thin film transistor 273, a first signal line 275, and a second signal line 277.

The first signal line 275 is disposed in parallel with the first driving signal line 233, and the second signal line 277 is disposed in parallel with the second driving signal line 235.

The second thin film transistor 272 and the third thin film transistor 273 are disposed in an area surrounded by the first signal line 275, the first driving signal line 233, the second signal line 277, and the second driving signal line 235. Is placed.

The second thin film transistor 272 includes a second gate electrode G2, a second source electrode S2, a second channel layer C2, and a second drain electrode D2. The second gate electrode G2 is insulated from the second channel layer C2. The second source electrode S2 and the second drain electrode D2 are electrically connected to the second channel layer C2. The second gate electrode G2 is electrically connected to the first signal line 275, and the second source electrode S2 is electrically connected to the second driving signal line 235. At this time, the second channel layer C2 is changed from the non-conductor to the conductor by light.

The third thin film transistor 273 includes a third gate electrode G3, a third source electrode S3, a third channel layer C3, and a third drain electrode D3. The third gate electrode G3 is insulated from the third channel layer C3 and changes the electrical characteristics of the third channel layer C3 from a nonconductor to a conductor. The third source electrode S3 and the third drain electrode D3 are electrically connected to the third channel layer C3. The third gate electrode G3 is electrically connected to the first driving signal line 233, the third source electrode S3 is electrically connected to the second drain electrode D2, and the third drain electrode D3 is It is electrically connected to the second signal line 277.

One photosensitive device 270 having such a configuration is formed for each of the plurality of second pixel regions 260. 2 and 4, the photosensitive device 270 may be formed in the second pixel area 260 facing the transparent pattern 148 of the first substrate 100 by a worker. This is to prevent the light applied to the photosensitive device 270 from being lost before being applied to the photosensitive device 270 to greatly improve the optical recognition rate of the photosensitive device 270.

The photosensitive signal is output to the second signal line 277 of the photosensitive device 270. The light detection signal is input to a detection signal processing module (not shown) that processes the light detection signal, and the detection signal processing module generates an image control signal. The image control signal is again applied to an information processing device (not shown) connected to the liquid crystal display, and the information processing device applies new image data to the liquid crystal display according to the image control signal.

Referring back to FIG. 1, the first substrate 100 and the second substrate 200 having such a configuration are coupled to each other, and a liquid crystal layer is provided between the first substrate 100 and the second substrate 200. crystal layer; 300 is interposed. The liquid crystal layer 300 is not an active device that generates light by itself, but a light receiving device that receives light. The arrangement of the liquid crystal layer 300 is changed by an electric field formed by a voltage difference, and the light transmittance is changed by the arrangement. Therefore, in order to change the transmittance of light from the liquid crystal layer 300, a first electrode and a second electrode are required.

6 is a cross-sectional view conceptually illustrating a first electrode and a second electrode of the liquid crystal display according to the present invention.

4 and 6, the first electrode 190 is disposed on the first substrate 100. The first electrode 190 is disposed on an upper surface of the red color filter 142, the green color filter 144, the blue color filter 146, and the transparent pattern 148. The first electrode 190 is formed by patterning a transparent and conductive tin indium oxide thin film (ITO film) or indium zinc oxide film (IZO film).

The second electrode 290 is disposed on the second substrate 200. The second electrode 290 is disposed in the first pixel region 250 and the second pixel region 260 of the second substrate 200, respectively. The second electrode 290 is connected to the first drain electrode D1 of the first thin film transistor 230 formed in each of the first pixel region 250 and the second pixel region 260. The second electrode 290 is formed by patterning a transparent and conductive tin indium oxide thin film (ITO film) or indium zinc oxide film (IZO film).

TN mode liquid crystal (Twist Nematic liquid crystal) or VA mode liquid crystal (Vertical Alignment mode liquid crystal) may be used for the liquid crystal layer 300 interposed between the first electrode 190 and the second electrode 290.

7 is a plan view conceptually showing another embodiment of a liquid crystal display according to the present invention. The first thin film transistor, the first and second driving signal lines of the liquid crystal display according to the present embodiment are the same as in the above-described embodiment. Therefore, the same members will be denoted by the same reference numerals as in the above-described embodiment, and redundant description thereof will be omitted.                     

Referring to FIG. 7, both the first electrode 192 and the second electrode 292 are disposed on the second substrate 200. The first electrode 192 is connected to the first drain electrode D1 of the first thin film transistor 230. As illustrated in FIG. 7, the first electrode 192 has a branch shape divided into a plurality of branches. The second electrode 292 is formed on the same layer as the first electrode 192. The second electrode 292 has a plurality of branched branches, and the second electrode 292 is disposed between the first electrodes 192. Therefore, the first electrode 192 and the second electrode 292 are alternately arranged.

As the liquid crystal layer 300 interposed between the first electrode 192 and the second electrode 292, VA mode liquid crystal or IPS mode liquid crystal is used. The first electrode 192 and the second electrode 292 are arranged horizontally on the second substrate 200, so that the liquid crystal layer 300 is disposed under the influence of the horizontal electric field, thereby viewing the viewing angle of the liquid crystal display device. Can be extended.

8 is a cross-sectional view conceptually showing another embodiment of a liquid crystal display according to the present invention.

Referring to FIG. 8, an organic film 299 having a thickness of several μm is interposed between the first thin film transistor 230 and the second electrode 294 of the second substrate 200. The organic film 299 is fabricated by patterning a thin film made of a photoresist material. The organic layer 299 increases the distance between the first driving signal line and the second driving signal line connected to the first thin film transistor 230 and the second electrode 294. As a result, the parasitic capacitance between the first driving signal line and the second driving signal line and the second electrode 294 is greatly reduced, and the aperture ratio of the liquid crystal display device is greatly improved, thereby increasing the luminance.                     

The second electrode 294 includes a metal electrode 294b formed by patterning a metal thin film. Alternatively, the second electrode 294 may use the transparent electrode 294a and the metal electrode 294b disposed on the upper surface of the transparent electrode 294a. In this case, the metal electrode 294b may be manufactured in a honeycomb form, or only a part of the metal electrode 294b may be opened.

In the above-described embodiments, a transparent pattern is formed on the first substrate 100 of the liquid crystal display device 800 in addition to the red color filter, the green color filter, and the blue color filter so that the sensing light is supplied to the photosensitive device 270 and the liquid crystal is provided. Although the luminance of the display device is improved, an opening suitable for passing sensing light is formed in a portion of the red, green, and blue color filters formed on the first substrate 100, and the second substrate 200 is formed. The same effect can be obtained even by forming an optical sensing element for outputting a sensing signal by the sensing light incident through the opening.

LCD display system

9 is a conceptual diagram illustrating a liquid crystal display system according to an embodiment of the present invention. The liquid crystal display device of the liquid crystal display system according to the present embodiment is the same as the embodiment described above. Therefore, the same members will be denoted by the same reference numerals as in the above-described embodiment, and redundant description thereof will be omitted.

Referring to FIG. 9, the liquid crystal display system includes a liquid crystal display device 800 and a light pen 900. The light pen 900 includes a body 910 and a light converter 920. The light converter 920 is disposed at the end of the body 910. In the present exemplary embodiment, the light converter 920 converts the red light RL, the green light GL, the blue light BL, or the white light WL emitted to the first substrate 100 into the sensing light SL. Convert In detail, in the present exemplary embodiment, the light converter 920 reflects the red light RL, the green light GL, the blue light BL, or the white light WL emitted to the first substrate 100. The sensing light SL reflected by the light converter 920 is directed toward the first substrate 100, and a part of the sensing light SL passes through the transparent pattern 148 and the liquid crystal layer 300 to sense the light. Device 270 is reached. Thus, the information processing device connected to the liquid crystal display device 800 controls the screen of the liquid crystal display device 800 by accurately recognizing the position of the light incident on the liquid crystal display device 800.

10 is a conceptual diagram of a liquid crystal display system according to another embodiment of the present invention. The liquid crystal display device of the liquid crystal display system according to the present embodiment is the same as the embodiment described above. Therefore, the same members will be denoted by the same reference numerals as in the above-described embodiment, and redundant description thereof will be omitted.

Referring to FIG. 10, the liquid crystal display system 900 includes a liquid crystal display device 800 and a light pen 950.

The light pen 950 includes a body 960, a light converter 970, a light generating module 980, and a detector 990.

The body 960 includes an empty space therein, and an opening is formed in a portion of the body 960 facing the light generating module 980.

The light converter 970 is disposed in the body 960. The light converter 970 converts a part of the red light RL, the green light GL, the blue light BL, or the white light WL into the first sensing light SL1. The light converter 970 has a through hole formed at a portion corresponding to the opening formed in the body 960.

The light generating module 980 and the detector 990 are disposed in an empty space formed inside the body 960.

The light generating module 980 includes a light source 982, a control unit 984, a power supply 986, and a switch 988. In this embodiment, the light source 982 is a light emitting diode (LED) having a small size and high luminance. The second sensing light SL2 is emitted from the light source 982. The power supply 986 provides a power source for generating the second sensing light SL2 to the light source 982. The control unit 984 controls the lighting and turning off of the light source 982.

The detector 990 is disposed in an inner empty space of the body 960 and is connected to the control unit 984 to transmit a detecting signal to the control unit 984. The detector 990 converts an analog signal such as red light RL, green light GL, blue light BL, or white light WL into a digital signal. In the present embodiment, the detector 990 uses a photo transistor or a photo diode.

The detector 990 periodically detects the amounts of the red light RL, the green light GL, the blue light BL, and the white light WL emitted to the first substrate 100 to control the detection signal. Output to (984). The detecting signal includes information related to the amount of light of the red light RL, the green light GL, the blue light BL, and the white light WL.

The control unit 984 compares the detecting signal of the detector 990 with a preset reference signal. The control unit 984 supplies power from the power supply 986 to the light source 982 when the light amount of the red light RL, the green light GL, the blue light BL, and the white light WL is lower than the designated light amount. Is applied to generate the second sensing light SL2 directed from the light source 982 toward the first substrate 100. The second sensing light SL2 is emitted toward the light sensing element 270 of the liquid crystal display device 800.

As such, generating the second sensing light SL2 in response to the light amounts of the red light, the green light, the blue light, and the white light is generated by the light conversion unit 970 when the light amount of the red light, the green light, the blue light, and the white light is small. This is because the amount of light of the first sensing light SL1 is also small.

According to the present exemplary embodiment, when the amount of red light, green light, blue light and white light is insufficient and the amount of light of the first sensing light SL1 is insufficient, the first substrate from the inside of the body 960 of the light pen 950. The second sensing light SL2 is generated through the light source 100 toward the photosensitive device 270 so that the light pen 950 normally uses, for example, a vertical alignment mode liquid crystal. Black mode (normally black mode) It is possible to operate smoothly even in a liquid crystal display.

As described in detail above, the optical recognition rate of the photosensitive device incorporated in the liquid crystal display device is greatly improved, thereby preventing malfunction of the photosensitive device and greatly improving the display quality of the liquid crystal display device.

Although embodiments of the present invention have all been described to perform a sensing operation by reflecting light generated from an external light source, alternatively, the present invention may be applied to a shadow method that forms a shadow by blocking a part of the light generated by the external light source. .

In the detailed description of the present invention described above with reference to a preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge of the present invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the spirit and scope of the art.

Claims (22)

A first substrate including a first light transmission region for filtering white light and emitting red, green and blue light, respectively, and a second light transmission region for transmitting the white light; An optical sensing element disposed in the first pixel region corresponding to the first light transmitting region, the second pixel region corresponding to the second light transmitting region, and the second pixel region to output a sensing signal by sensing light; A second substrate comprising a; A liquid crystal layer interposed between the first substrate and the second substrate; A first electrode disposed in the first and second pixel areas to control the liquid crystal included in the liquid crystal layer; And And a second electrode spaced apart from the first electrode to generate an electric field. The display device of claim 1, wherein the first light transmitting area comprises a red color filter, a green color filter, and a blue color filter. The display device of claim 1, wherein the second light transmission region comprises a transparent pattern through which the white light is transmitted. The display device of claim 1, wherein the first and second light transmitting regions are arranged in a matrix form. The display device of claim 1, wherein a first thin film transistor including a first gate electrode, a first source electrode, and a first drain electrode is disposed in the first and second pixel regions, respectively, and the first gate electrode is driven by a first driving electrode. And a first source electrode connected to a second driving signal line. The display device of claim 5, wherein the photosensitive device comprises: a first signal line disposed in parallel with the first driving signal line; A second thin film transistor including a second gate electrode connected to the first signal line, a second source electrode connected to the second driving signal line, a second drain electrode, and a second channel layer to which the sensing light is incident; A second signal line arranged in parallel with the second driving signal line; And a third thin film transistor including a third source electrode connected to the second drain electrode, a third gate electrode connected to the first driving signal line, a third drain electrode connected to the second signal line, and a channel layer. Display. The display device of claim 6, wherein the sensing light comprises the red, green, blue, and white lights. The display device of claim 1, wherein the first electrode is disposed on the first substrate, and the second electrode is disposed on the second substrate. The display device of claim 8, wherein the liquid crystal is a twisted nematic liquid crystal. The method of claim 1, wherein the first and second electrodes are disposed on the second substrate, the first electrode is divided into a plurality of parts, and the second electrode is interposed between the branched first electrodes. Display device characterized in that. The display device of claim 10, wherein the liquid crystal is a vertical alignment mode liquid crystal. The display device of claim 1, wherein the first electrode is a transparent and conductive indium tin oxide film or an indium zinc oxide film. The display device of claim 1, wherein the second electrode comprises a transparent and conductive indium tin oxide film or an indium zinc oxide film. The display device of claim 1, wherein the first electrode is disposed on the first substrate, and an organic layer is interposed between the first electrode and the first substrate. The display device of claim 14, wherein the first electrode comprises a reflective electrode. The display device of claim 14, wherein the first electrode comprises a transparent electrode and a reflective electrode disposed on an upper surface of the transparent electrode. The display device of claim 16, wherein the reflective electrode has a plurality of transmission windows. A color filter including an opening for filtering white light to emit red, green, and blue light, and receiving sensing light, and a transparent pattern disposed in the opening for receiving sensing light and passing the sensing light without loss. A first substrate; A second substrate disposed at a position at which the sensing light passing through the transparent pattern reaches and including an optical sensing device outputting a sensing signal by the sensing light; A liquid crystal layer interposed between the first substrate and the second substrate; First electrodes disposed in the first and second pixel areas of the second substrate to control the liquid crystal contained in the liquid crystal layer; And And a second electrode spaced apart from the first electrode to generate an electric field.  A first substrate including a first light transmission region for filtering white light and emitting red, green, and blue light, respectively, a first substrate including a second light transmission region for transmitting white light, and a first formed to correspond to the first light transmission region A second substrate comprising a first pixel region, a second pixel region formed corresponding to the second light transmitting region, and an optical sensing element disposed in the second pixel region to output a sensing signal by sensing light; And a liquid crystal layer interposed between the second substrate, a first electrode disposed in the first and second pixel regions to control the liquid crystal contained in the liquid crystal layer, and spaced apart from the first electrode to generate an electric field. A display device including a second electrode; And And a light pen including a light converter configured to convert the red, green, blue light and white light emitted from the first substrate into the sensing light. The display system of claim 19, wherein the light conversion unit comprises a light reflection unit for reflecting the red, green, blue light, and white light. 20. The method of claim 19, wherein the light pen is a body having a hollow, disposed inside the body to detect the light amount of the red, green, blue light and white light to output a detection signal when the light amount is less than a predetermined light amount And a light source for outputting light to the photosensitive device by the detector and the detecting signal. The display system of claim 21, wherein the light source is a light emitting diode.

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