KR20160043216A - Display device including fingerprinting device - Google Patents

Abstract

The present invention relates to a liquid crystal display apparatus including a fingerprinting device. The liquid crystal display apparatus includes: multiple gate lines and multiple data lines intersecting each other; and a display pixel or a sensing pixel disposed at an intersection of the gate line and the data line. Each sensing pixel can be connected to neighboring first and second gate lines and neighboring first and second data lines, thereby simplifying a structure, improving an aperture ratio, and reducing manufacturing costs.

Description

DISPLAY DEVICE INCLUDING FINGERPRINTING DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to a display device including a fingerprint recognition device.

On the other hand, in recent display devices, various functions are added in addition to the function of displaying images, and as a part thereof, researches on display devices including fingerprint recognition devices are being actively conducted.

In general, a display device having a fingerprint recognition device recognizes a fingerprint by an optical sensing method or a capacitive method. For example, as shown in FIG. 1, a liquid crystal display device that recognizes a fingerprint using an optical sensing method includes a photo sensor 120 as a fingerprint sensor in the liquid crystal panel 110. The photosensor 120 senses the light emitted from the backlight unit 100 and reflected by the finger 120 to recognize the fingerprint.

However, the conventional display device including the fingerprint recognition device has the following problems.

First, since the display device drives the fingerprint sensor and separate lines are configured to read the sensed information from the fingerprint sensor, the structure of the display panel becomes complicated and the aperture ratio of the display pixel is reduced.

Second, as shown in FIG. 2, the above-mentioned display device has a case in which a fingerprint recognition device is disposed externally in a non-display area. However, recent display devices are in a trend of reducing the area of a non-display area, There is a large space constraint to place.

Thirdly, even if a space for disposing the external type fingerprint recognition device is secured in the display device, the price of the external type fingerprint recognition device increases in proportion to the fingerprint recognition area, which increases the manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been devised to solve the above-described problems, and it is an object of the present invention to provide a display device including a fingerprint recognition device that simplifies the structure, increases the aperture ratio, and reduces manufacturing cost by eliminating separate lines for fingerprint sensing To be a technical challenge.

Other features and advantages of the invention will be set forth in the description which follows, or may be obvious to those skilled in the art from the description and the claims.

According to an aspect of the present invention, there is provided a display device including a fingerprint recognition device, the display device including first and second gate lines adjacent to each other and sensing pixels connected to neighboring first and second data lines, have.

According to the solution of the above-mentioned problems, the present invention has the following effects.

That is, the present invention drives a sensing pixel using first and second gate lines, reads fingerprint information sensed from a sensing pixel using first and second data lines, Out lines for reading information from the signal supply line and the sensing pixel can be deleted.

Therefore, the present invention can simplify the structure, improve the aperture ratio, and reduce manufacturing cost.

In addition to the effects of the present invention mentioned above, other features and advantages of the present invention will be described below, or may be apparent to those skilled in the art from the description and the description.

1 is a view illustrating a general liquid crystal display device for recognizing a fingerprint by an optical sensing method.
2 is a diagram illustrating an external fingerprint recognition device.
3 is a configuration diagram of a liquid crystal display device according to an embodiment of the present invention.
FIG. 4 is an exemplary view showing the pixel region shown in FIG. 3 in detail.
5 is an equivalent circuit diagram of the display pixel shown in Fig.
6 is an equivalent circuit diagram of the sensing pixel shown in FIG.
7 is a driving waveform diagram of the sensing pixel shown in Fig.
8A to 8C are views for explaining the arrangement of sensing pixels according to the first embodiment of the present invention.
9A and 9B are views for explaining the arrangement of sensing pixels according to the second embodiment of the present invention.
10 is a view for explaining a fingerprint recognition method of the present invention.

The meaning of the terms described herein should be understood as follows. The word " first, "" second," and the like, used to distinguish one element from another, are to be understood to include plural representations unless the context clearly dictates otherwise. The scope of the right should not be limited by these terms. It should be understood that the terms "comprises" or "having" does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. It should be understood that the term "at least one" includes all possible combinations from one or more related items. For example, the meaning of "at least one of the first item, the second item and the third item" means not only the first item, the second item or the third item, but also the second item and the second item among the first item, Means any combination of items that can be presented from more than one. The term "on" means not only when a configuration is formed directly on top of another configuration, but also when a third configuration is interposed between these configurations.

Hereinafter, preferred embodiments of a display device including a fingerprint recognition device according to the present invention will be described in detail with reference to the accompanying drawings.

The display device of the present invention may be applied to a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an organic light emitting display , OLED), electrophoresis (EPD), and the like. In the following embodiments, a liquid crystal display device will be described as an example of a flat panel display device, but it should be noted that the display device of the present invention is not limited to a liquid crystal display device.

3 is a configuration diagram of a liquid crystal display device according to an embodiment of the present invention. FIG. 4 is an exemplary view showing the pixel region PA shown in FIG. 3 in detail. 5 is an equivalent circuit diagram of the display pixel DP shown in Fig. 6 is an equivalent circuit diagram of the sensing pixel SP shown in FIG. 7 is a driving waveform diagram of the sensing pixel SP shown in Fig.

3, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel 10, a backlight unit 70, a timing controller 50, a gate driver 30, a data driver 40, (20), and a host (60).

The liquid crystal panel 10 includes an upper substrate and a lower substrate, an upper polarizer disposed on the upper substrate, a lower polarizer disposed below the lower substrate, and a liquid crystal layer between the upper substrate and the lower substrate. And a liquid crystal layer. The upper substrate may include a color filter, a common electrode, a black matrix, and the like. The common electrode may be provided on a lower substrate according to a liquid crystal driving method of the liquid crystal panel 10. [ The lower substrate 24 includes a plurality of gate lines GL and a plurality of data lines DL and a pixel region PA at intersections of the gate lines GL and the data lines DL. The liquid crystal panel 10 is divided into a display area AA for displaying an image and a non-display area NA defined for the outer area of the display area AA.

A display pixel DP or a sensing pixel SP is disposed at an intersection of the gate line GL and the data line DL, that is, the pixel region PA. For example, as shown in FIG. 4, the liquid crystal panel 10 may have mxn pixel regions PA defined by intersecting a plurality of gate lines GL and a plurality of data lines DL, A display pixel DP or a sensing pixel SP is arranged in each pixel region PA.

The display pixel DP includes a switching TFT Tl, a liquid crystal cell Clc, and a storage capacitor Cst, as shown in Fig.

The switching TFT Tl is turned on according to a scan signal supplied from the gate line GL to supply a data voltage supplied from the data line DL to the pixel electrode of the liquid crystal cell Clc.

The liquid crystal cell Clc includes a pixel electrode connected to the switching TFT Tl, a common electrode to which a common voltage is applied, and a liquid crystal layer.

The storage capacitor Cst charges the difference voltage between the data voltage applied to the pixel electrode and the common voltage applied to the common electrode to maintain the voltage of the liquid crystal cell Clc constant.

6, the sensing pixel SP includes a sensing TFT T2, a sensing capacitor SC, and a photodiode PD, and is connected between the first and second data lines DL1 and DL2. And is disposed between the second and third gate lines GL2 and GL3.

The sensing TFT T2 has a gate terminal connected to the set node N1 and disposed between the first and second data lines DL1 and DL2. The sensing TFT T2 connects the first and second data lines DL1 and DL2 to each other according to a voltage state of the set node N1. The sensing TFT T2 allows the voltage of the lead-out node N2 connected to the second data line DL2 to follow the voltage charged in the set node N1 in the source follow-up form in the fingerprint sensing mode .

On the other hand, the threshold voltage of the sensing TFT T2 may be set to be larger than the threshold voltage of the switching TFT T1 provided in the display pixel DP. This is to prevent the sensing TFT T2 from turning on and connecting the first and second data lines DL1 and DL2 to each other in the display mode. If the threshold voltage of the sensing TFT T2 is designed to be larger than the threshold voltage of the switching TFT T1 provided in the display pixel DP, a separate channel doping process is required, which may increase the process cost. Therefore, the present invention sets the threshold voltage of the photodiode PD higher than the threshold voltage of a general photodiode PD, and turns on the first and second data lines DL1 and DL2 when the sensing TFT T2 is turned on, May be prevented from connecting to each other.

The sensing capacitor SC is disposed between the first gate line GL1 and the set node N1 to form a capacitance. In the fingerprint sensing mode, the sensing capacitor SC increases the voltage charged in the set node N1 according to the first scan signal supplied from the first gate line GL1.

The photodiode PD is connected to the second gate line GL2 and the set node N1, respectively. The photodiode PD converts the light emitted from the backlight unit 70 and reflected through the fingerprint of the user into a reverse optical current and supplies the light to the set node N1. At this time, the amount of the photocurrent generated from the photodiode PD varies depending on whether the object reflecting the light is a ridge or a valley of the fingerprint. Here, the first photocurrent generated by the light reflected from the valley is larger than the second photocurrent generated by the light reflected from the ridge.

The switching unit T3 switches the precharge signal PRE to the second data line DL2 in the fingerprint sensing mode at the end of the second data line DL2. The switching unit T3 includes a precharging TFT T3 for supplying a precharging signal PRE to the second data line DL2 in response to a sensing mode signal SS provided from the host 60 . Here, the precharge signal PRE sequentially charges the lead-out nodes N2 of the sensing pixels SP connected to the second data line DL2 in the fingerprint sensing mode. The precharge signal PRE initializes the voltage of the readout node N2 after the readout period in which the voltage of the readout node N2 of each sensing pixel SP is read. To this end, the pre-charging signal PRE has a form of an AC signal smaller in width than a scan signal.

Hereinafter, a driving method of the sensing pixel SP will be described with reference to FIGS. 6 and 7. FIG.

First, as a second scan signal is applied to the second gate line GL2, a forward bias is applied to the photodiode PD. Thus, the voltage of the set node N1 is raised to the reset voltage. At this time, the reset voltage is set to be higher than the threshold voltage of the sensing TFT T2, and the threshold voltage of the photodiode PD can be set higher than the threshold voltage of the general grape diode PD.

Then, the set node N1 raised to the reset voltage is discharged until the first scan signal is applied to the first gate line GL1. Specifically, when the voltage of the set node N1 rises to the reset voltage, the photodiode PD becomes a reverse bias state. Accordingly, the photodiode PD causes a reverse current to flow in accordance with the light emitted from the backlight unit 70 and reflected through the fingerprint of the user, and the voltage of the set node N1 is discharged. At this time, the voltage of the set node N1 is discharged more when the object touching the liquid crystal panel 10 is the target, as compared with the case where the object touching the liquid crystal panel 10 is ridged.

Then, when the first scan signal is applied to the first gate line GL1, the voltage of the set node N1 is raised by the coupling phenomenon of the sensing capacitor SC. Thus, the sensing TFT T2 is turned on. Since the first data line DL1 maintains the high potential VDD, the voltage of the lead-out node N2 connected to the second data line DL2 is the gate voltage of the sensing TFT T2, That is, the voltage charged in the set node N1, in the form of a source follow. At this time, the voltage charged in the lead-out node N2 is outputted to the lead-out circuit 20 as fingerprint information of the user.

The period during which the sensing pixel SP outputs the sensing information to the lead-out circuit 20 as the first scan signal is applied to the first gate line GL1 is divided into a precharge period, a lead-out period, .

During the precharge period, the switching unit T3 applies a precharging signal PRE to the second data line DL2. Then, the lead-out node N2 is precharged to a specific voltage level.

During the readout period, the voltage of the lead-out node N2 is raised following the voltage of the set node N1 in accordance with the turn-on of the sensing TFT T2 and outputted to the lead-out circuit 20.

During the reset period, the voltage of the lead-out node N2 is initialized as the precharging signal PRE is polled.

As described above, each sensing pixel SP is connected to the first and second gate lines GL1 and GL2 adjacent to each other and the first and second data lines DL1 and DL2 adjacent to each other. The driving method of the present invention drives the sensing pixels SP using the first and second gate lines GL1 and GL2 and drives the sensing pixels SP using the first and second data lines DL1 and DL2. The driving signal supply line for driving the sensing pixels SP and the lead-out lines for reading information from the sensing pixels SP can be deleted.

The backlight unit 70 is disposed on the back side of the liquid crystal panel 10. The backlight unit 70 includes a plurality of light sources that are turned on and off by the backlight driver and emits light uniformly to the liquid crystal panel 10. The backlight unit 70 may be implemented as a direct type backlight unit 70 or an edge type backlight unit 70. [ The light source of the backlight unit 70 may include any one or two or more kinds of light sources such as HCFL (Cold Cathode Fluorescent Lamp), CCFL (Cold Cathode Fluorescent Lamp), EEFL (External Electrode Fluorescent Lamp) have.

The timing controller 50 operates in a display mode or a fingerprint sensing mode in response to a mode signal MODE provided from the host 60. [

In the display mode, the timing controller 50 receives digital video data of an input image from the host 60 via an interface such as a Low Voltage Differential Signaling (LVDS) interface or a TMDS (Transition Minimized Differential Signaling) And transmits it to the data driver 40. The timing controller 50 receives the synchronization signal SYNC from the host 60 and outputs a gate control signal and a data control signal for controlling the driving timings of the gate driver 30 and the data driver 40. Here, the synchronization signal SYNC includes a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE, and a main clock MCLK.

In the fingerprint sensing mode, the timing controller 50 controls the data driver 40 to apply the high potential voltage VDD to the first data lines DL1 connected to the sensing pixels SP.

The gate driver 30 sequentially generates a scan signal according to the gate control signal GCS provided from the timing controller 50 and shifts the swing voltage of the output to the gate on voltage and the gate off voltage. The scan signal output from the gate driver 30 is sequentially supplied to the gate lines GL in synchronization with the data voltage output from the data driver 40. [ Here, the gate-on voltage is a voltage equal to or higher than the threshold voltage of the switching TFT (T1) provided in the display pixel (DP), and the gate-off voltage is lower than the threshold voltage of the switching TFT (T1). The gate driver 30 is integrated in the form of an integrated circuit (IC), connected to the gate lines GL through a TAB (Tape Automated Bonding) process, or connected to a non-display region (NA) and connected to the gate lines (GL).

The data driver 40 samples and latches the digital video data RGB provided from the timing controller 50 in accordance with the data control signal provided from the timing controller 50. The data driver 40 converts the digital video data RGB to a positive or negative gamma compensation voltage to generate a data voltage. The data driver 40 supplies the converted data voltage to the data lines DL in synchronization with the scan signal output from the gate driver 30. [ The data driver 40 may be integrated in an integrated circuit (IC) form and connected to the data lines DL by a COG (Chip On Glass) process or a TAB process. In addition, the data driver 40 may be integrated into the timing controller 50 and implemented with a timing controller 50 and a single IC.

The data driver 40 applies the high potential voltage VDD to the first data lines DL1 connected to the sensing pixels SP in the fingerprint sensing mode.

The readout circuit 20 is activated in the fingerprint sensing mode and generates signals SDATA by reading the signals output from the sensing pixels SP of the liquid crystal panel 10 and supplies the sensed data SDATA to the host 60 do. To this end, the lead-out circuit 20 is electrically connected to each of the second data lines DL2 connected to the sensing pixel SP, and the current or voltage value output from the second data line DL2 is digital Into the signal inception data (SDATA), and supplies it to the host (60).

The host 60 transmits the digital video data RGB of the input video and the synchronization signals SYNC to the timing controller 50 via the interfaces such as the LVDS interface and the TMDS interface. Further, the host 60 transmits a display mode and a mode signal (MODE) indicating the fingerprint sensing mode to the timing controller 50. Further, the host 60 analyzes the sensing data (SDATA) provided from the lead-out circuit 20 according to a preset fingerprint sensing algorithm to calculate fingerprint information.

Meanwhile, in the liquid crystal display device according to the present invention, the sensing pixels SP may be disposed in the display area AA or in the non-display area NA.

In the liquid crystal display device according to the first embodiment of the present invention, the sensing pixels SP are provided in the display area AA, and the sensing pixels SP may be arranged as follows.

First, as shown in FIG. 8A, the sensing pixels SP may be disposed between the display pixels DP arranged adjacent to each other at specific intervals in the gate line GL direction. In this case, the display pixels DP and the sensing pixels SP are grouped in units of columns and arranged in the pixel area PA of the liquid crystal panel 10. [ For example, when m x n pixel regions PA are arranged in a matrix form, the display pixels DP may be arranged in odd-numbered columns, and the sensing pixels SP may be arranged in even-numbered columns.

Second, as shown in FIG. 8B, the sensing pixels SP may be disposed between the display pixels DP arranged adjacent to each other at specific intervals in the data line DL direction. In this case, the display pixels DP and the sensing pixels SP are grouped on a row-by-row basis and arranged in the pixel area PA of the liquid crystal panel 10. [ For example, when m x n pixel regions PA are arranged in a matrix form, the display pixels DP may be arranged in odd-numbered rows, and the sensing pixels SP may be arranged in even-numbered rows.

Third, as shown in FIG. 7C, the sensing pixels SP may be disposed between the display pixels DP which are adjacent to each other at specific intervals in the gate line GL direction and the data line DL direction. For example, when mxn pixel areas PA are arranged in a matrix form, the display pixels DP are arranged in odd-numbered columns and even-numbered rows, and the sensing pixels SP are arranged in an odd-numbered row and an even- As shown in Fig.

By arranging the sensing pixels SP in the display area AA, the first embodiment of the present invention can implement the fingerprint recognition function while balancing the trend of reducing the area of the non-display area NA. In addition, since separate lines for driving the sensing pixels SP are not provided in the display area AA, the aperture ratio can be improved.

In the liquid crystal display device according to the second embodiment of the present invention, the sensing pixels SP are provided in the non-display area NA, and the sensing pixels SP may be arranged as follows.

First, as shown in FIG. 9A, the sensing pixel SP may be a first sensing pixel SP disposed at an intersection of the data line DL and the dummy gate line DGL. Here, the dummy gate line DGL is provided in the non-display area NA separately from the gate lines GL provided in the display area AA. This dummy gate line DGL may be driven by the integrated gate driver 30, but is preferably driven by a separate dummy gate driver 35 as shown. This is for reducing unnecessary gate lines, that is, dummy gate lines (DGL) in the display mode, thereby reducing power consumption. To this end, the gate driver 30 and the dummy gate driver 35 receive the same clock signal, and start driving in response to different start pulses Vst1 and Vst2. The first sensing pixel SP may be disposed at a portion or an entirety selected from intersections of the data line DL and the dummy gate line DGL.

Second, as shown in FIG. 9B, the sensing pixel SP may be a second sensing pixel SP disposed at an intersection of the gate line GL and the dummy data line DDL. Here, the dummy data line DDL is provided in the non-display area NA separately from the data lines DL provided in the display area AA. This dummy data line DDL may be driven by the integrated data driver 40 as shown, but may also be driven by a separate data driver 40. Meanwhile, the second sensing pixels SP may be disposed at some or all of the intersections of the gate lines GL and the dummy data lines DDL.

The second embodiment of the present invention has a structure in which only the dummy gate line DGL or the dummy data line DDL is provided for driving the sensing pixel SP while the sensing pixel SP is disposed in the non-display area NA The structure is simpler than a general liquid crystal display device in which a plurality of lines are separately required for bar and fingerprint sensing. Therefore, the second embodiment can reduce the area of the non-display area.

The resolution of the sensing pixels SP according to the first and second embodiments may be varied as needed. That is, the spacing in which the sensing pixels SP are arranged in the gate line GL direction or the data line DL direction can be variously modified. However, it is preferable that the interval between the sensing pixels SP is set to be 0.4 mm or less in consideration of the widths of the ridges and valleys of the fingerprint.

On the other hand, as in the second embodiment, when the sensing pixels SP of the present invention are arranged in the non-display area NA, The fingerprint can be recognized by sliding the finger on the display area NA. At this time, the present invention can expand the arrangement area of the sensing pixels SP provided in the non-display area NA to simultaneously recognize two fingerprints as well as one fingerprint.

As described above, in the present invention, each sensing pixel SP is connected to the first and second gate lines GL1 and GL2 adjacent to each other and the first and second data lines DL1 and DL2 neighboring to each other. The driving method of the present invention drives the sensing pixels SP using the first and second gate lines GL1 and GL2 and drives the sensing pixels SP using the first and second data lines DL1 and DL2. The driving signal supply line for driving the sensing pixels SP and the lead-out lines for reading information from the sensing pixels SP can be deleted.

Therefore, the present invention can simplify the structure, improve the aperture ratio, and reduce manufacturing cost.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of. Therefore, the scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention.

10: liquid crystal panel 20: lead-out circuit
30: gate driver 40: data driver
50: timing controller 60: host
70: Backlight unit DP: Display pixel
SP: sensing pixel

Claims (6)

A display pixel or a sensing pixel is disposed at an intersection of the gate line and the data line,
Wherein the display pixels are connected to the gate lines and the data lines intersecting with each other,
Wherein the sensing pixel is connected to neighboring first and second gate lines and to neighboring first and second data lines. The method according to claim 1,
The sensing pixel
A sensing TFT having a gate terminal connected to the set node and disposed between the first and second data lines;
A sensing capacitor disposed between the first gate line and the set node; And
And a photodiode disposed between the second gate line and the set node. 3. The method of claim 2,
And a switching unit connected to an end of the second data line and supplying a precharging signal to the second data line in response to a sensing mode signal input to the gate terminal. The method according to claim 1,
The sensing pixel
And are disposed within the display region and between the display pixels neighboring each other at specific intervals in the gate line direction or the data line direction. The method according to claim 1,
Each of the sensing pixels
A first sensing pixel provided in a non-display area and disposed at an intersection of the data line and a dummy gate line provided in the non-display area,
And a second sensing pixel disposed at an intersection of the gate line and the dummy data line provided in the non-display area. 6. The method of claim 5,
Wherein the first sensing pixels are disposed at a portion or an entirety selected from intersections of the data line and the dummy gate line,
And the second sensing pixels are disposed in a part or all of the intersections of the gate line and the dummy data line.

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