TWI406162B - Photosensitive element and liquid crystal display with the same, readout pixel of liquid crystal display - Google Patents

Abstract

A photosensitive element includes a first conductive line, a second conductive line, a third conductive line, a read switch, a charging switch and a light sensing element. A control terminal of the read switch is electrically connected to the first conductive line, and a second terminal of the read switch is electrically connected to the third conductive line. A control terminal of the charging switch is electrically connected to the first conductive line, and a first terminal of the charging switch is electrically connected to the second conductive line. The light sensing element is electrically connected between a first terminal of the read switch and a second terminal of the charging switch; wherein when the first conductive line turns on the read switch and the charging switch, the light sensing element generates a photocurrent to the third conductive line through the read switch according to a voltage of the second conductive line and a light intensity incident to the light sensing element. The present invention further provides a liquid crystal display.

Description

Light sensing element and liquid crystal display comprising the same, liquid crystal display read pixel

The present invention relates to a touch device, and more particularly to a light sensing device and a liquid crystal display including the same.

Liquid crystal displays are currently widely used display devices. With the maturity of touch screen technology, various mobile electronic devices, such as multimedia players, mobile phones, and personal digital assistants (PDAs), are equipped with touch-screen LCD screens. The convenience of use is increased; wherein the optical touch screen detects the touch position by detecting changes in light intensity.

Referring to FIG. 1 , a light sensing component 9 of a conventional optical touch panel is shown, which includes a data line 91 , a scan line 92 , a read line 93 , a common line 94 , and a read . The transistor 95 and a photo transistor 96 are taken. The photosensitive transistor 96 has different photocurrent outputs according to the received light intensity. When the scanning line 92 receives a scanning signal and turns on the reading transistor 95, the photocurrent flows to the reading line 93. A processing unit (not depicted) can determine the location of the touch based on the photocurrent. However, since the photosensitive transistor 96 in Fig. 1 continues to be subjected to the common voltage of the common line 91, the photocurrent is attenuated under long-time operation.

In view of this, it is necessary to propose a light sensing element that does not suffer from the length of operation and affects the operational efficiency.

The present invention provides a light sensing element in which the photosensitive unit can be prevented from being inferior in performance under long-term operation because the photosensitive unit does not continue to be subjected to a voltage for a long period of time.

The invention further provides a liquid crystal display and a read pixel thereof, which can be combined with a pressing sensing structure to increase the change of the touch signal during the operation of the insufficient light, thereby improving the operation sensitivity.

The invention provides a light sensing component, comprising a first wire, a second wire, a third wire, a reading switch, a charging switch and a photosensitive unit. The read switch includes a control end, a first end and a second end; the control end of the read switch is electrically connected to the first wire, and the second end of the read switch is electrically connected to the The third wire. The charging switch includes a control end, a first end and a second end; the control end of the charging switch is electrically connected to the first wire, and the first end of the charging switch is electrically connected to the second wire . The photosensitive unit is electrically connected between the first end of the reading switch and the second end of the charging switch; wherein when the first wire turns on the reading switch and the charging switch, the photosensitive unit is according to the second wire The potential and the intensity of the light incident on the photosensitive unit generate a photocurrent through the read switch to the third conductor.

The present invention further provides a read pixel for a liquid crystal display, comprising a pixel transistor and a light sensing element simultaneously formed on an array substrate included in the liquid crystal display. The light sensing component further includes a first wire, a second wire, a third wire, a read switch, a charging switch and a photosensitive unit. The read switch includes a control end, a first end and a second end; the control end of the read switch is electrically connected to the first wire, and the second end of the read switch is electrically connected to the The third wire. The charging switch includes a control end, a first end and a second end; the control end of the charging switch is electrically connected to the first wire, and the first end of the charging switch is electrically connected to the second wire . The photosensitive unit is electrically connected between the first end of the reading switch and the second end of the charging switch; wherein when the first wire turns on the reading switch and the charging switch, the photosensitive unit is according to the second wire The potential and the intensity of the light incident on the photosensitive unit generate a photocurrent through the read switch to the third conductor.

The present invention further provides a liquid crystal display comprising a plurality of read pixels, an array substrate and a plurality of gate lines, a plurality of data lines, a plurality of common lines, and a plurality of third lines formed on the array substrate. Each read pixel further includes a pixel transistor and a light sensing element. The light sensing component further includes a read switch, a charging switch and a photosensitive unit. The read switch includes a control end, a first end and a second end; the control end of the read switch is electrically connected to one of the gate lines, and the second end of the read switch is electrically Sexually connected to one of the third wires. The charging switch includes a control end, a first end and a second end; the control end of the charging switch and the control end of the read switch are electrically connected to the gate line, and the first end of the charging switch is Electrically connected to one of the common lines. The photosensitive unit is electrically connected between the first end of the reading switch and the second end of the charging switch; wherein the gate line electrically connected to the charging switch and the control end of the reading switch is turned on a reading switch and the charging switch, the photosensitive unit generates a photocurrent according to the potential of the common line electrically connected to the first end of the charging switch and the light intensity incident on the photosensitive unit, and the photocurrent is passed through the reading switch to the first The third wire electrically connected to the two ends.

In the light sensing element, the read pixel and the liquid crystal display of the present invention, the charge can be accumulated in the photosensitive unit by adding a discharge switch, and a sensing structure can be matched to increase the sensing sensitivity when the light is insufficient. The pressing sensing structure is formed on the opposite substrate of the charging switch and facing the charging switch, and the conduction state of the charging switch can be changed by changing the distance between the charging switch and the pressing sensing structure. And thereby changing the photocurrent value generated by the photosensitive unit. The press sensing structure may be formed by a stack of at least one layer of spacers or color resists and an electrode layer of the surface of the protruding structure.

The above and other objects, features, and advantages of the present invention will become more apparent from the accompanying drawings. In the description of the present invention, the same components are denoted by the same reference numerals and will be described in the foregoing.

Moreover, only some of the components are shown in the various figures of the invention and components that are not directly related to the description of the invention are omitted.

Referring to Fig. 2, there is shown a circuit diagram of a photo sensing element according to a first embodiment of the present invention. The light sensing component 10 includes a first wire 111, a second wire 112, a third wire 113, a read switch 121, a photosensitive unit 122, and a charging switch 123. The reading switch 121 and the charging device The switch 113 can be, for example, a thin film transistor. The photosensitive unit 122 can be, for example, a thin film transistor, a photo diode, or a light sensitive resistor. The first wire 111 is used to control the opening and closing of the reading switch 121 and the charging switch 123. The second wire 112 is configured to provide a potential for driving the photosensitive unit 122, and the third wire 113 is used for reading a light. The current Ic is transmitted through the read switch 121 and the third wire 113 to a processing unit 8 for analysis. The photocurrent Ic is generated according to the potential of the second wire 112 and the intensity of light incident on the photosensitive unit 122. The present invention reduces the performance and reduces the generated photocurrent Ic by increasing the charging switch 123 to prevent the photosensitive unit 122 from being continuously subjected to the potential connected to the second wire 112.

The read switch 121 includes a control end 121a, a first end 121b and a second end 121c. The control end 121a is electrically connected to the first wire 111, and the second end 121c is electrically connected to the first end 121c. The three wires 113, wherein the first end 121b and the second end 121c are divided into other drains and sources. The charging switch 123 includes a control end 123a, a first end 123b and a second end 123c. The control end 123a is electrically connected to the first wire 111, and the first end 123b is electrically connected to the second end. The wire 112, wherein the first end 123b and the second end 123c can be divided into other drains and sources. The photosensitive unit 122 is coupled between the first end 121b of the read switch 121 and the second end 123c of the charging switch 123. For example, when the photosensitive unit 122 is a thin film transistor (TFT), it includes a control end. The first end 122b and the second end 122c are electrically connected to the first end 122b and electrically connected to the second end 123c of the charging switch 123. The second end 122c is electrically connected. The first end 121b and the second end 122c can be divided into other drains and sources. It can be understood that the above description assumes that the photosensitive unit 122 is a thin film transistor to illustrate the light sensing element 10 of the present invention; when the photosensitive unit 122 is a photodiode or a photoresistor, it may not have three connections. end.

When the first wire 111 simultaneously turns on the read switch 121 and the charge switch 123, the potential connected to the second wire 112 drives the photosensitive unit 122 to generate the photocurrent Ic according to the light intensity, and by The read switch 121 transmits the photocurrent Ic to the third wire 113.

When the light sensing component 10 is applied to a read pixel of a liquid crystal display, each component of the light sensing component 10 is formed on a TFT array substrate included in the liquid crystal display. The first wire 111 is, for example, a gate line on the array substrate or a wire controlled by a separate device, and the second wire 112 can be, for example, a common line on the array substrate. The third wire 113 can be, for example, a data line or a separately disposed wire on the array substrate.

Referring to FIG. 3, it is shown that the light sensing element 10 of the first embodiment of the present invention is applied to a layout of a liquid crystal display when reading pixels, and the components of the light sensing element 10 are formed on On the array substrate 30, the read pixel may further include a light shielding element 13 shielded over the first wire 111 and the third wire 113 to shield the light leakage from the edge of the pixel. In the present invention, in order to avoid affecting the aperture ratio of the read pixel, the read switch 121 and the charging switch 123 are preferably formed on the array substrate 30 by overlapping the first conductive line 111. It can be understood that some of the components are omitted in the read pixel in FIG. 3, for example, the data line and the pixel transistor coupled to the pixel electrode are omitted.

Referring to Figures 4A and 4B, there is shown a circuit diagram of a readout pixel of a liquid crystal display. An in-cell optical touch liquid crystal display comprising a plurality of general pixels (ie, pixels that do not include light sensing elements) and an array of read pixels (ie, pixels containing light sensing elements) formed in an array of liquid crystal displays On the array substrate, the read pixel can be formed on the array substrate in a ratio of a general pixel, and the higher the ratio of the read pixels, the higher the sensing resolution; wherein, the general pixel The structure is a conventional technique and will not be described here.

In Figure 4A, the present invention is to read one pixel 20 comprises a first gate line G _n, a second gate line G _{n + 1,} a data line D _n, a pixel transistor 21 and a light The sensing element 10 is formed on an array substrate. In this embodiment, the pixel transistor 21 is electrically connected to the light sensing element 10 to different gate lines. The pixel transistor 21 includes a control terminal 21a, 21b a first end and a second end 21c, the end 21a of the control system is electrically connected to the first gate line G _n, a first end of the line 21b is electrically connected to the data lines D _n, the second end 21c is electrically connected to a line of the liquid crystal capacitor C _LC and a storage capacitor C _ST. The light sensing device 10 is electrically connected between the second gate line G _n+1 , the second wire 112 and the third wire 113 , wherein the second wire 112 can be a plurality of common lines included in the array substrate In one of the plurality, the third wire 113 can be one of a plurality of data lines included in the array substrate (for example, but not limited to, one data line adjacent to the data line D _n ) or a plurality of separate readings One of the lines. The components of the photo-sensing element 10 are connected to the second gate line G _n+1 , the second wire 112 and the third wire 113 in a manner similar to that shown in FIG. 2 (ie, replacing the first wire 111 with the second wire The gate line G _n+1 ), so it will not be described here.

Figure 4B, the present invention is to read one pixel 20 'also includes a first gate line G _n, a second gate line G _{n + 1,} a data line D _n, a pixel transistor 21 and A photo sensing element 10 is formed on an array substrate. In this embodiment, the pixel transistor 21 is electrically connected to the photo sensing element 10 to the same gate line, for example, the gate line G _{n .} In addition, the connection manner of other components is similar to that of FIG. 4A, and thus will not be described herein. It can be understood that the array substrate of the liquid crystal display includes a plurality of gate lines and data lines alternately formed on the array substrate, and the gate lines G _n and G _n+1 are two of the gate lines. The data line D _{n is} one of the data lines.

Referring to Figures 5A and 5B, there is shown a light sensing element of a second embodiment of the present invention. The photo sensing element 10 ′ further includes a fourth wire 114 and a discharge switch 124 for discharging the photosensitive unit 122 to avoid accumulation of electric charges. A wire 111, a second conductive wire 112, a third wire 113, a read switch 121, a photosensitive unit 122, and a charging switch 123 are connected in the same manner as the first embodiment, and thus will not be described again. The discharge switch 124 can be a thin film transistor, and includes a control end 124a, a first end 124b and a second end 124c. The first end 124b and the second end 124c can be divided into other bungee The control terminal 124a is electrically connected to the fourth wire 114. The first end 124b is electrically connected to the control end 122a and the first end 122b of the photosensitive unit 122. The second end 124c is electrically connected. Connected to the first wire 111. When the light sensing element 10 ' is applied to a read pixel of a liquid crystal display, the components of the light sensing element 10 ' are formed on an array substrate.

FIG. 5A is a schematic diagram showing the first wire 111 simultaneously opening the reading switch 121 and the charging switch 123. The third wire 113 reads out a photocurrent Ic generated by the photosensitive unit 122 from the light intensity. At this time, the fourth wire 114 does not turn on the discharge switch 124, so the discharge switch 124 does not function at this time.

FIG. 5B shows a schematic diagram of the fourth wire 114 opening the discharge switch 124. At this time, the first wire 111 has a low potential, for example, -7 volts, and the read switch 121 and the charge switch 123 are turned off, and the charge accumulated in the photosensitive unit 122 can be discharged to the first wire during this period. 111.

It can be understood that the optical sensing component 10 ' of the second embodiment of the present invention can also be applied to a read pixel of a liquid crystal display, as shown in FIGS. 4A and 4B, at this time, the first wire 111 and The fourth wires 114 can be two gate lines, for example, two adjacent gate lines G _n , G _n+1 .

According to another embodiment of the present invention, in order to increase the sensing sensitivity of the light sensing element 10 or 10 ' at low light intensity, a pressing sensing structure may be further disposed above the charging switch 123. For example, when the light sensing element 10 or 10 ' is formed on one of the array substrates 30 of a liquid crystal display, the pressing sensing structure is formed on one of the opposite substrates of the array substrate 30.

Referring to FIGS. 6A and 6B, a cross-sectional view taken along line 6-6 ' in FIG. 3 includes an array substrate 30 and a pair of substrates 40. The charging switch 123 is formed on the array substrate 30. The pressing sensing structure 41 is formed on the opposite substrate 40 with respect to the charging switch 123. In one embodiment, the charging switch 123 includes a gate layer G, a gate insulating layer 1231, a channel layer 1232, a doped layer 1233, a source layer S, a drain layer D, and a protective layer. 1234 is formed on the array substrate 30, wherein the materials and formation manner of each layer are conventional techniques, and thus will not be described herein. The pressing sensing structure 41 may be formed by stacking a plurality of layers of photoresist or forming a spacer and an electrode layer 411. For example, in the 6A and 6B drawings, the pressing sensing structure 41 is formed by stacking three layers of color resists R, G, and B, and an electrode layer 411 is further formed on the surface of the pressing sensing structure 41.

According to this configuration, the conduction state of the channel layer 1232 is affected by the interaction of the voltage of the gate layer G and the electrode layer 411. 6A is a cross-sectional view showing the opposite substrate 40 when it is not pressed by an external force, wherein the distance between the electrode layer 411 and the charging switch 123 is, for example, d1; and FIG. 6B shows that the opposite substrate 40 is pressed by an external force. A cross-sectional view of the time in which the distance between the electrode layer 411 and the charging switch 123 becomes, for example, d2. At this time, the electric field of the electrode layer 411 will lower the conduction state of the channel layer 1232. Therefore, when a finger or a stylus presses the light sensing element 10 or 10 ′ , the light intensity detected by the photosensitive unit 122 is lowered to reduce the generated photocurrent Ic, and the electrode layer 411 and the electrode layer 411 The distance of the charging switch 123 is shortened to further reduce the conduction state of the charging switch 123 to lower the driving voltage to the photosensitive unit 122, and further reduce the generated photocurrent Ic. In this embodiment, the multiplication of the two effects can make the change of the touch signal generated when the light sensing component 10 or 10 ' is touched more obvious, so as to increase the touch sensitivity of the liquid crystal display. It can be understood that the touch signal can be a current or voltage signal converted according to the photocurrent Ic, or is the photo current Ic. In addition, the detailed implementation of the press sensing structure 41 can be referred to the content disclosed in the applicant's Republic of China Patent Publication No. 200910168.

As described above, since one of the photosensitive sensing structures in the conventional light sensing structure is continuously subjected to a voltage during operation, the photocurrent generated by the photosensitive unit is attenuated due to a long-time operation, resulting in a touch event. The change in photocurrent is less pronounced, thus reducing operational sensitivity. The present invention avoids the problem that the photosensitive unit (such as Figures 2, 5A and 5B) continues to be subjected to voltage by adding a charging switch. In addition, the present invention can also prevent charge accumulation in the photosensitive unit by adding a discharge switch (such as Figures 5A and 5B); and can cooperate with a pressing sensing structure (such as Figures 6A and 6B) to increase the light deficiency. Sensing sensitivity.

The present invention has been disclosed in the foregoing embodiments, and is not intended to limit the present invention. Any of the ordinary skill in the art to which the invention pertains can be modified and modified without departing from the spirit and scope of the invention. . Therefore, the scope of the invention is defined by the scope of the appended claims.

10,10 ' . . . Light sensing component

111. . . First wire

112. . . Second wire

113. . . Third wire

114. . . Fourth wire

121. . . Read switch

121a. . . Read switch control terminal

121b. . . Read the first end of the switch

121c. . . Read the second end of the switch

122. . . Photosensitive unit

122a. . . Control terminal of the photosensitive unit

122b. . . First end of the photosensitive unit

122c. . . Second end of the photosensitive unit

123. . . Charging switch

123a. . . Control terminal of the charging switch

123b. . . First end of the charging switch

123c. . . Second end of the charging switch

1231. . . Gate insulation

1232. . . Channel layer

1233. . . Doped layer

1234. . . The protective layer

124. . . Discharge switch

13. . . Shading element

20, 20 ' . . . Reading pixels

twenty one. . . Pixel crystal

30. . . Array substrate

40. . . Counter substrate

41. . . Press sensing structure

411. . . Electrode layer

8. . . Processing unit

G _n , G _n+1 . . . Gate line

D _n . . . Data line

C _LC . . . Liquid crystal capacitor

C _ST . . . Storage capacitor

Ic. . . Photocurrent

R, G, B. . . Photoresist

9. . . Light sensing component

91. . . Data line

92. . . Scanning line

93. . . Read line

94. . . Common line

95. . . Reading transistor

96. . . Photoelectric crystal

Figure 1 shows a circuit diagram of a conventional light sensing element.

Fig. 2 is a view showing the light sensing element of the first embodiment of the present invention.

Fig. 3 is a view showing the layout of components of the light sensing element of Fig. 2.

Fig. 4A is a circuit diagram showing a read pixel including one of the photo sensing elements of the first embodiment of the present invention.

Fig. 4B is a diagram showing another circuit diagram for reading a pixel including one of the photo sensing elements of the first embodiment of the present invention.

Figure 5A is a diagram showing a light sensing element of a second embodiment of the present invention, wherein the light sensing element operates in a read mode.

Figure 5B shows another schematic view of a light sensing element in accordance with a second embodiment of the present invention, wherein the light sensing element operates in a discharge mode.

Fig. 6A is a cross-sectional view taken along line 6-6 ' of Fig. 3, wherein a pressing sensing structure is formed on the pair of substrates facing the charging switch.

Fig. 6B shows another cross-sectional view taken along line 6-6 ' in Fig. 3, in which the opposite substrate is pressed by an external force.

10. . . Light sensing component

111. . . First wire

112. . . Second wire

113. . . Third wire

121. . . Read switch

121a. . . Read switch control terminal

121b. . . Read the first end of the switch

121c. . . Read the second end of the switch

122. . . Photosensitive unit

122a. . . Control terminal of the photosensitive unit

122b. . . First end of the photosensitive unit

122c. . . Second end of the photosensitive unit

123. . . Charging switch

123a. . . Control terminal of the charging switch

123b. . . First end of the charging switch

123c. . . Second end of the charging switch

Ic. . . Photocurrent

8. . . Processing unit

Claims (11)

A light sensing component comprising: a first wire; a second wire; a third wire; a fourth wire; a read switch comprising a control end, a first end and a second end, the reading The control terminal of the switch is electrically connected to the first wire, and the second end of the read switch is electrically connected to the third wire; a charging switch includes a control end, a first end and a second The control end of the charging switch is electrically connected to the first wire, the first end of the charging switch is electrically connected to the second wire; and the discharging switch comprises a control end, a first end and a a second end, wherein the control end of the discharge switch is electrically connected to the fourth wire, the first end of the discharge switch is electrically connected to the second end of the charging switch, and the second end of the discharge switch is electrically connected Connected to the first wire; wherein the first wire and the fourth wire are two gate lines; and a photosensitive unit electrically connected to the first end of the read switch and the second end of the charging switch Wherein the first wire turns on the read switch and the charging switch, The light unit generates a current flows through the reading light switch according to the third conductor wire of the second electric potential and the intensity of the light incident on the photosensitive unit. The photo sensing element according to claim 1, wherein the photosensitive unit is a thin film transistor, a photodiode or a photoresistor; The first wire is a gate line; the second wire is a common line; the third wire is a data line; the read switch and the charging switch are a thin film transistor. The light sensing device of claim 1, wherein the charging switch is formed on an array substrate, the array substrate faces a pair of substrates, and a protruding structure is formed on the opposite substrate from the opposite substrate. The charging switch extends and an electrode layer is formed on the surface of the protruding structure, wherein the photocurrent value generated by the photosensitive unit is changed by changing a distance between the charging switch and the electrode layer to change an on state of the charging switch; The protruding structure is formed by spacers or color resists. A read pixel of a liquid crystal display, comprising: a pixel transistor formed on an array substrate included in the liquid crystal display; and a light sensing component formed on the array substrate, the light sensing component The method comprises: a first wire; a second wire; a third wire; a fourth wire; a data line; a read switch comprising a control end, a first end and a second end, the read switch The control end is electrically connected to the first guide a second end of the read switch is electrically connected to the third wire; a charging switch includes a control end, a first end and a second end, and the control end of the charging switch is electrically connected to a first wire, the first end of the charging switch is electrically connected to the second wire; a discharge switch includes a control end, a first end and a second end, wherein the control end of the discharge switch is electrically The first end of the discharge switch is electrically connected to the second end of the charging switch, and the second end of the discharge switch is electrically connected to the first wire; the first wire and the first wire The fourth wire is a two-gate line of the array substrate; the pixel electro-crystal system is electrically connected between the first wire and the data line or electrically connected between the fourth wire and the data line; The photosensitive unit is electrically connected between the first end of the reading switch and the second end of the charging switch; wherein when the first wire turns on the reading switch and the charging switch, the photosensitive unit is according to the second wire The potential and the intensity of light incident on the photosensitive unit produce a photoelectric Through the wire to the third read switch. The reading pixel according to item 4 of the patent application, wherein the photosensitive unit is a thin film transistor, a photodiode or a photoresistor; the first wire is a gate line on the array substrate; the second The wire is a common line on the array substrate; the read switch, the charging switch and the pixel transistor are a thin film transistor. According to the reading pixel of the fourth aspect of the patent application, the method further comprises: a pair of facing substrates facing the array substrate, wherein the protruding substrate forms a protruding structure extending from the opposite substrate toward the charging switch and an electrode layer is formed on the pixel The surface of the protruding structure, wherein the photocurrent value generated by the photosensitive unit is changed by changing a distance between the charging switch and the electrode layer to change a conduction state of the charging switch; wherein the protruding structure is formed by a spacer or a color resistor Formed. According to the reading pixel of the fourth aspect of the patent application, wherein the read switch and the charging open relationship are formed on the array substrate overlapping the first wire; the read pixel further comprises a light blocking component formed on Above the first wire. A liquid crystal display comprising: an array substrate; a plurality of gate lines formed on the array substrate; a plurality of data lines formed on the array substrate across the gate lines; and a plurality of common lines formed on the array substrate; a plurality of third wires formed on the substrate; and a plurality of read pixels, each of the read pixels further comprising: a pixel transistor; and a light sensing component, the light sensing component further comprising: a reading The switch includes a control end, a first end and a second end, and the control end of the read switch is electrically connected to the control end One of the gate lines, the second end of the read switch is electrically connected to one of the third wires; a charging switch includes a control end, a first end and a second end, The control terminal of the charging switch is electrically connected to the gate line electrically connected to the control end of the read switch, and the first end of the charging switch is electrically connected to one of the common lines; a discharge switch a control terminal, a first terminal, and a second terminal, wherein the control terminal of the discharge switch is electrically connected to another gate line, which is electrically connected to the control terminal of the read switch a gate line, the first end of the discharge switch is electrically connected to the second end of the charging switch, and the second end of the discharge switch is electrically connected to the gate electrically connected to the control end of the read switch a pole line; the pixel transistor is electrically connected between the gate line electrically connected to the control end of the read switch and the data line, or is electrically connected to the control end of the read switch One of the gate lines is adjacent to the data line and the data line; and a photosensitive unit is electrically charged Connecting between the first end of the read switch and the second end of the charging switch; wherein the gate switch electrically connected to the charging switch and the control end of the read switch turns on the read switch and the charging a switch, the photosensitive unit generates a potential according to the common line electrically connected to the first end of the charging switch and a light intensity incident on the photosensitive unit A photocurrent is passed through the read switch to the third wire electrically connected to the second end of the read switch. The liquid crystal display according to claim 8 , wherein the photosensitive unit is a thin film transistor, a photodiode or a photoresistor; the read switch, the charging switch and the pixel transistor are a thin film transistor. The liquid crystal display according to claim 8 , further comprising a pair of facing substrates facing the array substrate, wherein the opposite substrate forms a protruding structure extending from the opposite substrate toward the charging switch and an electrode layer is formed on the protruding layer a surface of the structure, wherein the photocurrent value generated by the photosensitive unit is changed by changing a distance between the charging switch and the electrode layer to change an on state of the charging switch; wherein the protruding structure is formed by a spacer or a color resist . The liquid crystal display of claim 8, wherein the read switch and the charge-on relationship are formed on the array substrate in a manner overlapping with the gate lines.