KR20100130057A - Input device - Google Patents

Abstract

PURPOSE: An input device receives an input of a signal from the external side by using the green light, thereby improving touch sensitivity. CONSTITUTION: An input unit includes a light source(11) and a display panel(20). The light source generates light. The display panel receives the light. The display panel displays an image. The display panel comprises a color filter(120) and a sensing element(230). The color filter converts the light into green light. The sensing element senses the green light.

Description

Input device {INPUT DEVICE}

An embodiment relates to an input device.

BACKGROUND With the development and popularization of graphical user interface (GUI) systems, the use of touchscreens with simple inputs has become commonplace.

In addition, with the development of information processing technology, display devices such as LCD, PDP and AMOLED are widely used. In particular, an optical touch integrated LCD including an optical sensor in an LCD panel is used.

Embodiments provide an input device having an improved touch sensitivity and minimizing an error caused by external noise.

An input device according to one embodiment includes a light source for generating light; And a display panel configured to receive the light and display an image, the display panel comprising: a color filter converting the light into green light; And a sensing device for sensing the green light.

An input device according to one embodiment includes a light source for generating green light; And a display panel configured to receive the green light and display an image, wherein the display panel includes a sensing element that senses the green light.

The input device according to the embodiment may sense a signal such as a touch input from the outside using green light.

In this case, the input device according to the embodiment may include a sensing element including amorphous silicon, and the sensing element including amorphous silicon has excellent sensing sensitivity with respect to green light. That is, amorphous silicon has a light absorption ratio with respect to linear wavelength change with respect to light of a green wavelength.

Therefore, since the input device according to the embodiment receives a signal from the outside by using green light, it has an improved touch sensitivity and can easily distinguish external noise.

In the description of the embodiments, each substrate, element, member, panel, electrode, pattern, or layer is placed on or under the "on" of each substrate, element, member, panel, electrode, pattern, or layer. And " under " include both " directly " or " indirectly " through other components. . In addition, the upper or lower reference of each component is described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 is a cross-sectional view illustrating a cross section of a liquid crystal display according to an embodiment. 2 is a circuit diagram illustrating a green pixel of a liquid crystal display according to an exemplary embodiment. 3 is a cross-sectional view showing a cross section of the photo TFT. 4 is a diagram illustrating a process of sensing an external signal by the liquid crystal display according to the exemplary embodiment. 5 and 6 are waveform diagrams showing signals applied to the first line and the second line.

1 to 6, the liquid crystal display includes a backlight unit 10 and a liquid crystal panel 20.

The backlight unit 10 generates light and emits the light toward the liquid crystal panel 20. For example, the backlight unit 10 generates white light and emits the light evenly on the rear surface of the liquid crystal panel 20.

The backlight unit 10 is interposed between a light guide plate disposed below the liquid crystal panel 20, a light emitting diode 11 generating light to inject light into a side surface of the light guide plate, and the light guide plate and the liquid crystal panel 20. It may include an optical sheet or the like.

In addition, the backlight unit 10 may include a reflective sheet disposed under the light guide plate, the light guide plate, the light emitting diode 11, the optical sheet, and a frame accommodating the reflective sheet.

The liquid crystal panel 20 receives light emitted from the backlight unit 10 and displays an image. In more detail, the liquid crystal panel 20 receives light generated from the light emitting diodes 11 and displays an image by adjusting the intensity of light transmitted in each pixel unit.

As shown in FIG. 1, the liquid crystal panel 20 includes an upper substrate 100, a lower substrate 200, and a liquid crystal layer 300.

The upper substrate 100 is opposite to the lower substrate 200. The upper substrate 100 includes a first transparent substrate 110, a color filter layer 120, and a common electrode layer 130.

The first transparent substrate 110 is a transparent, insulating substrate. The first transparent substrate 110 may be, for example, a glass substrate, a plastic substrate, or a quartz substrate. The first transparent substrate 110 supports the color filter layer 120 and the common electrode layer 130.

The color filter layer 120 filters the light passing through the liquid crystal layer 300 and converts the light into color light. The color filter layer 120 includes a black matrix pattern 121, a red color filter 122, a green color filter 123, and a blue color filter 124 that block light passing therethrough.

The red color filter 122 filters the white light passing through and converts the white light into red light. The green color filter 123 filters the white light passing through and converts the white light into green light. For example, the green color filter 123 filters the white light passing through and converts the white light into light of about 500 nm to about 600 nm.

The blue color filter 124 filters white light passing through and converts the white light into blue light.

The common electrode layer 130 is disposed under the color filter layer 120. The common electrode layer 130 includes a common electrode for applying an electric field to the liquid crystal layer 300.

The lower substrate 200 is opposite to the upper substrate 100. The lower substrate 200 includes a second transparent substrate 210 and a TFT layer 220.

The second transparent substrate 210 is transparent and is an insulating substrate. The second transparent substrate 210 may be, for example, a glass substrate, a plastic substrate, or a quartz substrate. The second transparent substrate 210 supports the TFT layer 220.

The TFT layer 220 is disposed on the second transparent substrate 210. The TFT layer 220 applies an electric field to the liquid crystal layer 300. The TFT layer 220 includes a plurality of wires, a plurality of switching elements, a plurality of electrodes, and a plurality of sensing elements 230.

The TFT layer 220 includes a plurality of gate wires 221 extending in a first direction and a plurality of data wires 222 extending in a second direction crossing the gate wires 221.

In addition, a plurality of pixels are defined by the gate lines 221 and the data lines 222. In this case, the pixels are divided into a red pixel PX1, a green pixel PX2, and a blue pixel PX3 by the color filters 122, 123, and 124.

That is, the red pixel PX1 corresponds to the red color filter 122 and displays a red image. The green pixel PX2 corresponds to the green color filter 123 and displays a green image. Similarly, the blue pixel PX3 corresponds to the blue color filter 124 and displays a blue image.

In addition, the TFT layer 220 is disposed on each pixel and the first thin film transistor 223 disposed in an area where the gate line 221 and the data line 222 intersect, and the first thin film transistor ( 223 includes a pixel electrode 224 selectively connected to the data line 222. That is, the first thin film transistor 223 is a switching unit for selectively connecting the pixel electrode 224 and the data line 222.

The pixel electrode 224 forms an electric field with the common electrode by a data signal applied through the data line 222, and the liquid crystal is formed by an electric field formed between the common electrode and the pixel electrode 224. Layer 300 is driven such that the optical properties are changed.

As shown in FIGS. 1 and 2, the TFT layer 220 includes a sensing element 230, a lead-out wiring 226, and first and second driving voltage wirings 227 disposed on the green pixel PX2. 228, a second thin film transistor 229.

The sensing element 230 is disposed corresponding to the green color filter 123. The sensing element 230 may be disposed corresponding to the through hole 125 formed in the green color filter 123. The sensing element 230 senses light input from the outside.

As shown in FIG. 3, the sensing element 230 is, for example, a photo TFT 230 that senses light input from the outside.

The photo TFT 230 includes a gate electrode 231, a gate insulating layer 232, an active layer 233, a source electrode 234, a drain electrode 235, and a passivation layer 237.

The gate electrode 231 is disposed on the second transparent substrate 210 and is connected to the second driving voltage line 228.

The gate insulating layer 232 covers the gate electrode 231 and insulates the active layer 233 from the gate insulating layer 232. The gate insulating layer 232 covers the gate wiring 221.

The active layer 233 is disposed on the gate insulating layer 232. The active layer 233 receives light incident from the outside. That is, the active layer 233 may receive external light and adjust the intensity of the current flowing between the source electrode 234 and the drain electrode 235 according to the intensity of the external light.

The active layer 233 includes amorphous silicon. In more detail, the active layer 233 is made of amorphous silicon.

The source electrode 234 and the drain electrode 235 are connected to the active layer 233 and spaced apart from each other. In more detail, the source electrode 234 and the drain electrode 235 are in contact with the active layer 233 through the ohmic contact layer 236.

The source electrode 234 is connected to the first driving voltage line 227, and the drain electrode 235 is connected to the second thin film transistor 229.

The passivation layer 237 covers the source electrode 234 and the drain electrode 235.

The photo TFT 230 senses light input from the outside. That is, the photo TFT 230 adjusts the intensity of the current flowing between the source electrode 234 and the drain electrode 235 according to the intensity of light input from the outside. Accordingly, the intensity of light input to the photo TFT 230 may be measured through the intensity of the current passing through the photo TFT 230.

As the sensing element 230, a photo diode including amorphous silicon as well as the photo TFT may be used.

The lead-out wire 226 transmits an electric signal formed by converting the intensity of the current sensed from the photo TFT 230, that is, the intensity of light, to the driver. The driving unit reads an input electrical signal to determine a position where a signal such as a touch is input.

The first and second driving voltage wires 227 and 228 apply a driving voltage to the photo TFT 230. As described above, the first driving voltage line 227 is connected to the source electrode 234 and the second driving voltage line 228 is connected to the gate electrode 231.

The second thin film transistor 229 selectively transmits an electrical signal sensed from the photo TFT 230 to the readout wiring 226. That is, the second thin film transistor 229 selectively connects the photo TFT 230 and the lead-out wiring 226. That is, the second thin film transistor 229 is a switching unit for selectively connecting the photo TFT 230 and the lead-out wiring 226.

In addition, the second thin film transistor 229 is connected to the gate line 221 and is driven by a signal applied through the gate line 221.

Unlike the illustrated in FIG. 2, the second thin film transistor 229 may be driven by a driving signal applied through a different wiring from the gate wiring 221.

The TFT layer 220 temporarily stores a signal generated from the first storage capacitor Cst1 and the photo TFT 230 temporarily storing a data signal applied to the pixel electrode 224. It may further include (Cst2).

The liquid crystal layer 300 is interposed between the upper substrate 100 and the lower substrate 200. The liquid crystal layer 300 is driven by an electric field formed between the pixel electrode 224 and the common electrode.

The lower substrate 200 and the upper substrate 100 may further include an alignment layer adjacent to the liquid crystal layer 300.

In addition, the liquid crystal panel 20 may include a polarizing sheet disposed below the lower substrate 200 and on the upper substrate 100.

As shown in FIG. 4, the liquid crystal display according to the exemplary embodiment senses a signal such as a touch by using green light.

As illustrated in FIG. 5, a first gate signal GS1 for displaying an image on the gate line of the first line and emitting light for sensing an external touch is applied.

The first gate signal GS1 includes a first period PD1 for displaying an image and a second period PD2 for emitting green light.

During the first period PD1, signals DS1, DS2, DS3..., For displaying an image are applied to the entire data line 222. During the second period PD2, the green pixel PX2 is applied. The constant signal DS2 is applied only to the data line corresponding to the.

Similarly, as shown in FIG. 6, the second gate signal GS2 is applied to display an image on the gate line of the second line and to emit light for sensing an external touch.

The second gate signal GS2 includes a third period PD3 for displaying an image and a fourth period PD4 for emitting green light.

During the third period PD3, signals DS1, DS2, DS3..., For displaying an image are applied to the entire data line 222, and the green pixel PX2 is applied during the fourth period PD4. The constant signal DS2 is applied only to the data line corresponding to the.

In the same manner, gate signals are applied to the gate lines 221 of the entire line.

Accordingly, during the second period PD2 and the fourth period PD4, green light having a predetermined size and wavelength is emitted through the green pixels PX2, and part of the emitted green light is reflected by a finger or the like. And enters again.

The length of the second period PD2 and the fourth period PD4 may be about 1 ms or less.

In this case, the incident green light is sensed by the sensing element 230, and a position of a finger or the like is input by the sensing element 230 and the driver.

Since the sensing device 230 includes amorphous silicon, the sensing device 230 generates an electrical signal having a different size according to the green light reflected by the finger and the green light input from the outside.

At this time, the amorphous silicon has a light absorption ratio with respect to the linear wavelength change with respect to the light of the green wavelength. Accordingly, the sensing element 230 generates an electrical signal whose intensity varies linearly according to the difference in the wavelength of the green light.

Therefore, the driver can easily determine the electrical signal input from the sensing element 230, it can easily determine the position of the finger.

Accordingly, the liquid crystal display according to the embodiment is an input device having an improved touch sensitivity and minimizing an error caused by external noise.

7 is a diagram illustrating a liquid crystal display according to another exemplary embodiment. 8 is a diagram illustrating a process of sensing a position of a finger by a liquid crystal display according to another exemplary embodiment. 9 is a waveform diagram illustrating a signal applied to a first line. In the present embodiment, with reference to the above-described embodiment, the backlight unit, the color filter layer, and the like will be further described. In the description of the present embodiment, the description of the foregoing embodiment may be fundamentally combined.

7 to 9, the backlight unit 30 includes a red light source 31, a green light source 32, and a blue light source 33. For example, the backlight unit 30 includes a red light emitting diode 31, a green light emitting diode 32, and a blue light emitting diode 33.

The backlight unit 30 sequentially emits red light, green light, and blue light to the liquid crystal panel 40. In detail, the backlight unit 30 uniformly emits red light generated from the red light source 31 to the rear surface of the liquid crystal panel 40, and then outputs the green light generated from the green light source 32. The liquid crystal panel 40 is uniformly emitted to the rear surface.

Thereafter, the green light generated from the blue light source 33 is uniformly emitted to the rear surface of the liquid crystal panel 40.

The liquid crystal panel 40 does not include a color filter. That is, the liquid crystal panel 40 displays an image having a color by using the red light, the green light, and the blue light.

As illustrated in FIG. 8, the liquid crystal display according to the present exemplary embodiment uses green light to sense a signal such as a position of a finger, that is, a touch.

Referring to FIG. 9, the liquid crystal display according to the exemplary embodiment sequentially turns on the red light source 31, the green light source 32, and the blue light source 33 to display an image, and then displays the green light source. Turn on 32 to generate green light for sensing the position of the finger or the like.

In this case, the green light source 32 may emit green light for sensing a signal such as a touch for a very short time, for example, about 10 μs to about 16 μs.

The green light emitted from the green light source 32 is reflected by a finger or the like, and the sensing element 430 included in the liquid crystal panel 40 senses the light reflected by the finger or the like.

Since the sensing element 430 includes amorphous silicon, the wavelength of the green light emitted from the green light source 32 and the wavelength of the green light input from the outside can be easily identified.

Therefore, the liquid crystal display according to the present exemplary embodiment is an input device having an improved touch sensitivity and minimizing an error caused by external noise.

10 is a circuit diagram illustrating a green pixel according to another exemplary embodiment. In the description of the present embodiment, except for the modified part, the above-described embodiment may be essentially combined.

Referring to FIG. 10, the TFT layer includes a third storage capacitor Cst3 and a third driving voltage line Vdd.

The third storage capacitor Cst3 is connected to the pixel electrode 224 and stores charge for driving a photo TFT. In addition, the third storage capacitor Cst3 is connected to the gate of the photo TFT.

The third driving voltage line Vdd is disposed in parallel with the data line Data (m). The third driving voltage line Vdd supplies a driving voltage to the source of the photo TFT.

According to the intensity of light irradiated onto the photo TFT, a difference in photo leakage current generated by the photo TFT occurs. That is, the intensity of the light leakage current of the photo TFT touched by a finger or the like may be greater or smaller than the intensity of the light leakage current of another photo TFT.

As described above, electric charges are stored in the second storage capacitor Cst2 by the light leakage current generated by the photo TFT.

The charge stored in the second storage capacitor Cst2 is transferred to the driver as an analog signal through the readout wiring RO by the operation of the second TFT. In this case, the driver converts the analog signal transmitted through the lead-out wire RO into a digital signal.

In this case, the driving unit calculates the touched position as coordinates based on the digital signal.

As described above, the liquid crystal display according to the present exemplary embodiment may sense the input touch signal by storing charge in the storage capacitor.

Although the above description has been made based on the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains may not have been exemplified above without departing from the essential characteristics of the present embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is a cross-sectional view illustrating a cross section of a liquid crystal display according to an embodiment.

2 is a circuit diagram illustrating a green pixel of a liquid crystal display according to an exemplary embodiment.

3 is a cross-sectional view showing a cross section of the photo TFT.

4 is a diagram illustrating a process of sensing an external signal by the liquid crystal display according to the exemplary embodiment.

5 and 6 are waveform diagrams showing signals applied to the first line and the second line.

7 is a diagram illustrating a liquid crystal display according to another exemplary embodiment.

8 is a diagram illustrating a process of sensing a position of a finger by a liquid crystal display according to another exemplary embodiment.

9 is a waveform diagram illustrating a signal applied to a first line.

Claims (7)

A light source for generating light; And And a display panel which receives the light and displays an image. The display panel A color filter converting the light into green light; And And an sensing device for sensing the green light. A light source for generating green light; And And a display panel which receives the green light and displays an image. The display panel includes a sensing element for sensing the green light. The input device according to claim 1 or 2, wherein the green light has a wavelength of 500 nm to 600 nm. The method of claim 1, The display panel A gate wiring extending in the first direction; A data line crossing the gate line; A pixel electrode facing the color filter; A first switching unit selectively connecting the data line and the pixel electrode; A driver configured to receive an electrical sensing signal formed by converting the green light from the sensing element; And And a second switching unit selectively connecting the driving unit and the sensing element. The input device of claim 4, wherein the first switching unit and the second switching unit are driven by a driving signal applied through the gate wiring. The input device of claim 1 or 2, wherein the sensing element comprises amorphous silicon. The input device of claim 1, wherein the sensing element is disposed corresponding to the color filter.

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