Summary of the invention
The invention provides a kind of touch driving circuit and driving method thereof, in order to solve the threshold voltage shift of existing driving transistors and the even thus problem causing whole screen display uneven of the current unevenness causing flowing through different Organic Light Emitting Diode when receiving identical data voltage, also solve current consumption electronic product simultaneously and require that screen volume is less, thickness is thinner, the problem that weight is lighter.
In order to solve the problem, the invention provides a kind of touch driving circuit, comprising:
Data-signal input block, for receiving data-signal, and sends data voltage;
Touch signal generation unit, for producing touch signal in touch signal reconnaissance phase;
Luminescence unit, for carrying out luminescence display;
Luminous controling unit, is connected to luminescence unit, for the luminescence display at pixel driver display stage control luminescence unit;
Driver element, is connected to touch signal generation unit and luminous controling unit respectively, for amplifying the touch signal that described touch signal generation unit produces in touch signal reconnaissance phase, drives described luminous controling unit in the pixel driver display stage;
Touch detection unit, is connected to driver element, for detecting the touch signal amplified through driver element in touch signal reconnaissance phase; And
Threshold compensation unit, be connected to data-signal input block and driver element respectively, for in the touch signal reconnaissance phase stage, the grid voltage of described driver element is made to equal the threshold voltage of described driver element, and receive the data voltage that data-signal input block sends, make the grid voltage of described driver element equal described data voltage and described threshold voltage sum; And in the pixel driver display stage, make the constant current hold flowing through described driver element.
Preferably, described luminescence unit comprises the Organic Light Emitting Diode for luminescence.
Preferably, described luminous controling unit comprises the first transistor, and the grid of described the first transistor is connected with luminous signal (EM) line, and the first pole is connected with described driver element, and the second pole is connected with luminescence unit.
Preferably, described touch detection unit comprises transistor seconds, and the grid of described transistor seconds is connected with selection signal wire, and the first pole is connected with described driver element, and the second pole is connected with touch detecting sensor.
Preferably, described driver element comprises third transistor and the 4th transistor, and the grid of described third transistor is connected with described threshold compensation unit, and the first pole is connected with the second pole of the 4th transistor, and the second pole is connected with the first pole of described transistor seconds; The grid of described 4th transistor is connected with the second scan signal line, and the first pole is connected with high voltage end (VDD), and the second pole is connected with described threshold compensation unit.
Preferably, described threshold compensation unit comprises the 5th transistor, the 6th transistor and the first capacitor, the grid of described 5th transistor is connected with the 3rd scan signal line, and the first pole is connected with described touch signal generation unit, and the second pole is connected with the first pole of described third transistor; The first end of described first capacitor is connected with data-signal input block, and the second end is connected with the first end of described 5th transistor; The grid of described 6th transistor is connected with described second scan signal line, and the first pole is connected with data-signal input block, and the second pole is connected with the second pole of described third transistor.
Preferably, described touch signal generation unit comprises the 7th transistor and photodiode, and the grid of described 7th transistor is connected with selection signal wire, and the first pole is connected with the second end of the first capacitor, and the second pole is connected with the first end of photodiode; Second end of described photodiode is connected with low-voltage end.
Preferably, described data-signal input block comprises the 8th transistor, and the grid of described 8th transistor is connected with the first scan signal line, and the first pole is connected with data signal line, and the second end is connected with the first end of described first capacitor.
Preferably, described the first transistor, transistor seconds, third transistor, the 4th transistor, the 5th transistor, the 7th transistor and the 8th transistor are N-type TFT, and described 6th transistor is P-type TFT.
Present invention also offers a kind of driving method being applied to above-mentioned touch driving circuit, comprising:
Touch signal detecting step, the touch signal for producing touch unit detects and determines the coordinate of touch location; And
Pixel driver step display, the grid voltage being provided for driver element equals the data voltage of data-signal input block output and the threshold voltage sum of described driver element, thus makes the constant current hold flowing through driver element.
Preferably, described touch signal detecting step comprises:
Initialization step, in described initialization step, the grid voltage controlling described driver element equals the voltage of high voltage end, and controls described luminescence unit by described luminous controling unit and be in off working state;
Voltage compensation step, in described voltage compensation step, the grid voltage controlling described driver element equals the threshold voltage of described driver element;
Data write step, in described data write step, input data voltage by described data-signal input block to described threshold compensation unit, and make the grid voltage of described driver element equal the data voltage of described data-signal input block output and described threshold voltage sum; And
Touch detecting step, in described touch detecting step, produce touch signal by described touch signal generation unit and amplify via described driver element, and being detected the touch signal amplified through described driver element by exterior I C.
Preferably, described initialization step comprises: control described third transistor, described 4th transistor, described 5th transistor and described 8th transistor turns, controls described the first transistor, described transistor seconds, the 6th transistor and described 7th transistor cutoff.
Preferably, described voltage compensation step comprises: control described third transistor, described 5th transistor, described 6th transistor and described 8th transistor turns, controls described the first transistor, described transistor seconds, described 4th transistor and described 7th transistor cutoff.
Preferably, described data write step comprises: control described third transistor, described 4th transistor and described 8th transistor turns, controls described the first transistor, described transistor seconds, described 5th transistor, described 6th transistor and described 7th transistor cutoff.
Preferably, described touch detecting step comprises: control described transistor seconds, described third transistor, described 4th transistor and described 7th transistor turns, control described the first transistor, described 5th transistor, described 6th transistor and described 8th transistor cutoff.
Preferably, in described pixel driver step display, control described transistor seconds and described 7th transistor cutoff, and described pixel driver step display comprises:
Initialization step, in described initialization step, the grid voltage controlling described driver element equals the voltage of high voltage end, and controls described luminescence unit by described luminous controling unit and be in off working state;
Voltage compensation step, in described voltage compensation step, the grid voltage controlling described driver element equals the threshold voltage of described driver element;
Data write step, in described data write step, input data voltage by described data-signal input block to described threshold compensation unit, and make the grid voltage of described driver element equal the data voltage of described data-signal input block output and described threshold voltage sum; And
Light-emission display step, in described light-emission display step, control the voltage constant at described first capacitor two ends, thus flow through the constant current hold of described driver element, and make described luminescence unit be in duty by luminous controling unit described in described drive unit drives.
Preferably, described initialization step comprises: control described third transistor, described 4th transistor, described 5th transistor and described 8th transistor turns, controls described the first transistor and described 6th transistor cutoff.
Preferably, described voltage compensation step comprises: control described third transistor, described 5th transistor, described 6th transistor and described 8th transistor turns, controls described the first transistor, described 4th transistor cutoff.
Preferably, described data write step comprises: control described third transistor, described 4th transistor and described 8th transistor turns, controls described the first transistor, described 5th transistor and described 6th transistor cutoff.
Preferably, described light-emission display step comprises: control described the first transistor, described third transistor and described 4th transistor turns, controls described 5th transistor, described 6th transistor and described 8th transistor cutoff.
Optical touch circuit of the present invention had both had built-in fixed point touch function, having again can the driving Presentation Function of compensating threshold voltage, thus achieve the integration of internally-arranged type touch function and AMOLED pixel driver Presentation Function, be conducive to doing thinner by display screen, lighter, and then reduce production cost.Additionally by employing timesharing drive principle, namely, first carry out the detecting of optical touch signal, and then carry out the display of AMOLED pixel driver, thus threshold voltage compensation is carried out after determining touch position coordinates, namely by being in saturated diode, threshold voltage being write capacitor to provide driving tube gate source voltage, the cut-in voltage of the drive current of driving tube and the threshold voltage of driving tube and OLED being had nothing to do, thus reaches the consistent of electric current.And then achieve brightness uniformity and the reliability of display screen.
Embodiment
Touch-screen can be divided into externally positioned type (external) and internally-arranged type (in-cell) two class.Externally positioned type touch-screen as the term suggests be exactly on a display panel face place a touching device again.And In-cell touch screen is owing to being incorporated in display panel, the volume of consumer electronics product therefore can be made less, and thickness is thinner, and weight is lighter.Optical touch circuit in the embodiment of the present invention is the hybrid circuit with internally-arranged type optical touch function and AMOLED pixel driver Presentation Function.
Below in conjunction with drawings and Examples, specific implementation of the present invention is described in detail.
With reference to the structured flowchart that Fig. 1, Fig. 1 are the optical touch circuit 100 according to the embodiment of the present invention.Optical touch circuit 100 comprises: luminescence unit 101, luminous controling unit 102, touch signal generation unit 103, driver element 104, touch detection unit 105, data-signal input block 106 and threshold compensation unit 107.
Luminescence unit 101 is connected to luminous controling unit 102 and low-voltage end (VSS) respectively, comprises the Organic Light Emitting Diode for luminescence, and for carrying out luminescence display in the pixel driver display stage.
Luminous controling unit 102 is connected to luminescence unit 101, driver element 104 and touch detection unit 105 respectively, for driving the luminescence display of display stage control luminescence unit 101 in luminescence.
Touch signal generation unit 103 is connected to driver element 104 and low-voltage end (VSS) respectively, for producing touch signal in touch signal reconnaissance phase.
Driver element 104 is connected to touch signal generation unit 103, threshold compensation unit 107, high voltage end (VDD) and touch detection unit 105 and luminous controling unit 102 respectively, for amplifying the touch signal that touch signal generation unit 103 produces in touch signal reconnaissance phase, drive luminous controling unit 102 in the pixel driver display stage.
Touch detection unit 105 is connected to driver element 104, threshold compensation unit 107 and luminous controling unit 102 respectively, for detecting the touch signal amplified through driver element 104 in touch signal reconnaissance phase.
Data-signal input block 106 is connected to threshold compensation unit 107, for receiving data-signal, and exports data voltage (Vdata) to threshold compensation unit 107.
Threshold compensation unit 107 is connected to data-signal input block 106, driver element 104, touch detection unit 105 and luminous controling unit 102 respectively, for in touch signal reconnaissance phase, the grid voltage of driver element 104 is made to equal the threshold voltage of described driver element 104, and receive the data voltage that data-signal input block 106 sends, make the grid voltage of driver element 104 equal described data voltage and described threshold voltage sum; And in the pixel driver display stage, make the constant current hold flowing through driver element 104.
Wherein, the voltage that high voltage end (VDD) exports is greater than the voltage that low-voltage end (VSS) exports.
The optical touch circuit that the present embodiment provides both had had internally-arranged type fixed point touch function, having again can the driving Presentation Function of compensating threshold voltage, thus achieve the integration of internally-arranged type touch function and AMOLED pixel driver Presentation Function, be conducive to doing thinner by display screen, lighter, and then reduce production cost.Prior art owing to adopting two circuit be provided separately (for detecting touch, another is for driving), thus causes complex circuit designs, and easily produces interference between the signal of two circuit.In addition, by being in saturated diode, threshold voltage being write capacitor to provide driving tube gate source voltage, the cut-in voltage of the drive current of driving tube and the threshold voltage of driving tube and OLED being had nothing to do, thus reaches the consistent of electric current.And then achieve brightness uniformity and the reliability of display screen.
Be the process flow diagram of the driving method of optical touch circuit according to the embodiment of the present invention with reference to Fig. 2, Fig. 2, this driving method comprises the following steps:
Touch signal detecting step 201, the touch signal for producing touch signal generation unit detects and determines the coordinate of touch location; And
Pixel driver step display 202, the grid voltage being provided for driver element equals the data voltage of data-signal input block output and the threshold voltage sum of described driver element, thus makes the constant current hold flowing through driver element.
During touch signal detecting step 201, obtain photodiode and point the differentiation signal that the reflection of backlight is produced when experiencing illumination and under the shade of finger or half-light, these differentiation signals are detected, and determines the coordinate of touch location.Thus realize fixed point touch function.
During pixel driver step display 202, by being in saturated diode, threshold voltage is write capacitor, the gate source voltage of driving transistors is provided, the cut-in voltage of the drive current of driving transistors and the threshold voltage of driving transistors and Organic Light Emitting Diode is had nothing to do, thus keep electric current consistent, improve homogeneity and the reliability of display screen.
With reference to the structured flowchart that Fig. 3, Fig. 3 are optical touch circuit 100 according to another embodiment of the present invention.Optical touch circuit 100 comprises: luminescence unit 101, luminous controling unit 102, touch signal generation unit 103, driver element 104, touch detection unit 105, data-signal input block 106 and threshold compensation unit 107.
Luminescence unit 101 is for carrying out luminescence display in the pixel driver display stage.
Luminous controling unit 102 is for driving the luminescence display of display stage control luminescence unit 101 in luminescence.
Touch signal generation unit 103 is for producing touch signal in touch signal reconnaissance phase.
The touch signal that driver element 104 produces for amplifying touch signal generation unit 103 in touch signal reconnaissance phase, drives luminous controling unit 102 in the pixel driver display stage.
Touch detection unit 105 is for detecting the touch signal amplified through driver element 104 in touch signal reconnaissance phase.
Data-signal input block 106 for receiving data-signal, and exports data voltage (Vdata) to threshold compensation unit 107.
Threshold compensation unit 107 is in touch signal reconnaissance phase, the grid voltage of driver element 104 is made to equal the threshold voltage of described driver element 104, and receive the data voltage that data-signal input block 106 exports, make the grid voltage of driver element 104 equal described data voltage and described threshold voltage sum; And in the pixel driver display stage, make the constant current hold flowing through driver element 104.
Below the concrete structure of above-mentioned unit is described.
Luminescence unit 101 comprises the Organic Light Emitting Diode (OLED) for luminescence.Luminous controling unit 102 comprises the first transistor T1.Touch detection unit 105 comprises transistor seconds T2.Driver element 104 comprises third transistor T3 and the 4th transistor T4.Threshold compensation unit 107 comprises the 5th transistor T5, the 6th transistor T6 and the first capacitor Cst.Touch signal generation unit 103 comprises the 7th transistor T7 and photodiode PD.Data-signal input block 106 comprises the 8th transistor T8.
Particularly, the grid of the first transistor T1 is connected with luminous signal (EM) line, and the first pole is connected with second pole of third transistor T3, and the second pole is connected with OLED.
The grid of transistor seconds T2 is connected with selection signal (Select) line, and the first pole is connected with the second pole of the 6th transistor, and the second pole is connected with touch detecting sensor (Sensor).
The grid of third transistor T3 is connected with the first end of capacitor Cst, and the first pole is connected with second pole of the 4th transistor T4, and the second pole is connected with first pole of transistor seconds T2.
The grid of the 4th transistor T4 is connected with the second sweep signal (Vscan2) line, and the first pole is connected with high voltage end VDD, and the second pole is connected with second pole of the 5th transistor T5.
The grid of the 5th transistor T5 is connected with the 3rd sweep signal (Vscan3) line, and the first pole is connected with first pole of the 7th transistor T7, and the second pole is connected with first pole of third transistor T3.
The first end of the first capacitor Cst is connected with second pole of the 8th transistor T8, and the second end is connected with first pole of the 5th transistor T5.
The grid of the 6th transistor is connected with described second sweep signal (Vscan2) line, and the first pole is connected with second pole of the 8th transistor T8, and the second pole is connected with second pole of third transistor T3.
The grid of the 7th transistor T7 is connected with selection signal (Select) line, and the first pole is connected with second end of the first capacitor Cst, and the second pole is connected with the first end of photodiode PD.
Second end of photodiode PD is connected with low-voltage end VSS.
The grid of the 8th transistor T8 is connected with the first sweep signal (Vscan1) line, and the first pole is connected with data-signal (Vdata) line, and the second end is connected with the first end of the first capacitor Cst.
In the present embodiment, the voltage that high voltage end VDD exports is greater than the voltage that low-voltage end VSS exports.The optical touch circuit of the present embodiment adopts timesharing to drive, and namely first carries out the detecting of built-in touch screen signal, then carries out luminescence and drives display.During built-in touch screen signal detection, the first transistor T1, transistor seconds T2, the 5th transistor T5, the 6th transistor T6, the 7th transistor T7 and the 8th transistor T8 are control tube, and third transistor T3 is driving tube.During luminescence drives display, the first transistor T1, the 4th transistor T4, the 5th transistor T5, the 6th transistor T6 and the 8th transistor T8 are switching tube, third transistor T3 is driving tube, and select signal (Select) to be low level, transistor seconds T2 and the 7th transistor T7 is in cut-off state.
Preferably, in the present embodiment, the first transistor T1, transistor seconds T2, third transistor T3, the 4th transistor T4, the 5th transistor T5, the 7th transistor T7 and the 8th transistor T8 can be N-type TFT, and the 6th transistor T6 can be P-type TFT.But this instructions is not limited the type of above-mentioned transistor.
With reference to the process flow diagram that Fig. 4, Fig. 4 are the driving methods of optical touch circuit according to another embodiment of the present invention.This driving method adopts timesharing to drive, and namely first performs touch signal detecting step 401, then performs pixel driver step display 402.
Fig. 5 is the sequential chart of the optical touch circuit according to illustrated embodiments of the invention.
The sequential chart of composition graphs 5, is first described touch signal detecting step 401.At initialization step 4011, control photodiode PD and be in off working state.Particularly, during this step, first sweep signal (Vscan1), the second sweep signal (Vscan2), the 3rd sweep signal (Vscan3) are set to high level, by data-signal (Vdata), select signal (Select) and luminous signal (EM) to be set to low level.Like this, transistor T4, T5, T3, T6 and T8 conducting, transistor T1, T2, T6 and T7 end.Via transistor T8, data-signal Vdata is write node A as shown in Figure 3, the voltage at node A place is low level.High voltage VDD writes Node B as shown in Figure 3 by transistor T4 and T5, and the voltage at Node B place is VDD.Because transistor T7 is in cut-off state, therefore photodiode PD is in off working state.
At voltage compensation step 4012 place, the grid voltage controlling driver element 104 equals the threshold voltage vt h of driver element 104.Particularly, during this step, first sweep signal (Vscan1) and the 3rd sweep signal (Vscan3) are set to high level, by the second sweep signal (Vscan2), data-signal (Vdata), select signal (Select) and luminous signal (EM) to be set to low level.Like this, transistor T1, T2, T4 and T7 end, transistor T3, T5, T6 and T8 conducting.The voltage at Node B place is by transistor T5, T3 and T6 electric discharge, and transistor T3 is saturated, thus the tension discharge at Node B place is to threshold voltage vt h.
At data write step 4013 place, control data signal input unit 106 inputs data voltage Vdata to threshold compensation unit 107, and the grid voltage controlling driver element 104 equals data voltage Vdata and the threshold voltage vt h sum of data-signal input block 106 output.Particularly, during this step, first sweep signal (Vscan1), the second sweep signal (Vscan2) and data-signal (Vdata) are set to high level, by the 3rd sweep signal (Vscan3), select signal (Select) and luminous signal (EM) to be set to low level.Like this, transistor T1, T2, T5, T6 and T7 end, transistor T3, T4 and T8 conducting.Data-signal (Vdata) writes node A via transistor T8, and now node B voltage is Vdata+Vth.Transistor T3 is still in on-state, but photodiode PD does not still work.
In touch detecting step 4014, driver element amplifies the touch signal that touch signal generation unit produces, and is detected the touch signal amplified through described driver element by exterior I C.Particularly, during this step, second sweep signal (Vscan2) and selection signal (Select) are set to high level, the first sweep signal (Vscan1), the 3rd sweep signal (Vscan3), data-signal (Vdata) and luminous signal (EM) are set to low level.Like this, transistor T2, T3, T4 and T7 conducting, transistor T1, T5, T6 and T8 end.Due to transistor T7 conducting, under photodiode PD is in illumination, photodiode PD under light illumination (no touch) is different with leakage current when (having touch) under shade, and under illumination, the leakage current of photodiode PD is larger than leakage current during unglazed photograph.The leakage current that electric charge on first capacitor Cst produces by illumination due to photodiode PD and significantly reducing.Thus the voltage causing Node B place declines to a great extent.The decline of Node B place voltage can cause the electric current flowing through transistor T3 to reduce.The electric current of this reduction flows through transistor T2 and is sent to IC.The size of this reduction electric current is relevant to light intensity, and the electric current of the larger generation of light intensity is larger.Touch signal generation unit, based on the leakage current variable quantity of photodiode PD in no touch and when having touch, produces touch signal.This touch signal causes the change of B point voltage, and the change of B point voltage is sent to IC by sensor signal lines after transistor T3 amplification and carries out detecting parsing, to determine whether respective pixel position has touch.
Hereinafter, pixel driver step display 402 is described.In the present embodiment, adopt mode luminous on Organic Light Emitting Diode, compared with lower illumination mode, there is higher aperture opening ratio.During this step, signal (Select) will be selected to be set to low level, and transistor T2 and T7 is in cut-off state.
At initialization step 4021, control described photodiode PD and be in off working state.Particularly, during this step, first sweep signal (Vscan1), the second sweep signal (Vscan2), the 3rd sweep signal (Vscan3) are set to high level, data-signal (Vdata), luminous signal (EM) are set to low level.Like this, transistor T3, T4, T5 and T8 conducting, transistor T1 and T6 ends.Via transistor T8, data-signal Vdata is write node A as shown in Figure 3, the voltage at node A place is low level.High voltage VDD writes Node B as shown in Figure 3 by transistor T4 and T5, and the voltage at Node B place is VDD.Because transistor T7 is in cut-off state, therefore photodiode PD is in off working state.
In voltage compensation step 4022, the grid voltage controlling driver element 104 equals the threshold voltage vt h of driver element 104.Particularly, during this step, first sweep signal (Vscan1) and the 3rd sweep signal (Vscan3) are set to high level, the second sweep signal (Vscan2), data-signal (Vdata) and luminous signal (EM) are set to low level.Like this, transistor T1 and T4 ends, transistor T3, T5, T6 and T8 conducting.The voltage at Node B place is by transistor T5, T3 and T6 electric discharge, and transistor T3 is saturated, thus the tension discharge at Node B place is to threshold voltage vt h.
In data write step 4023, control data signal input unit 106 inputs data voltage Vdata to threshold compensation unit 107, and makes the grid voltage of driver element 104 equal data voltage Vdata and the threshold voltage vt h sum of the output of described data-signal input block 106.Particularly, during this step, first sweep signal (Vscan1), the second sweep signal (Vscan2) and data-signal (Vdata) are set to high level, the 3rd sweep signal (Vscan3), luminous signal (EM) are set to low level.Like this, transistor T1, T5 and T6 end, transistor T3, T4 and T8 conducting.Data-signal (Vdata) writes node A via transistor T8, and now node B voltage is Vdata+Vth.
At light-emission display step 4024, control the voltage constant at the first capacitor Cst two ends, thus flow through the constant current hold of driver element 104.Particularly, during this step, second sweep signal (Vscan2) and luminous signal (EM) are set to high level, the first sweep signal (Vscan1), the 3rd sweep signal (Vscan3), data-signal (Vdata) are set to low level.Like this, transistor T1, T3 and T4 conducting, transistor T5, T6 and T8 end.The voltage of the left end A Nodes of the first capacitor Cst is ground voltage VSS.Now, the right-hand member (that is, the grid voltage of transistor T3) of the first capacitor Cst, due to unsettled and saltus step occurs, make the voltages keep constant at the first capacitor Cst two ends, namely keeps the voltage VB=Vdata+Vth at Node B place.Now the electric current of transistor T3 is:
I＝k(Vgs-vth)^2＝k(Vdata+Vth-Vth)^2＝k(Vdata)^2
Which eliminate the impact of the threshold voltage vt h of transistor T3.Thus improve the homogeneity of the electric current flowing through transistor T3, achieve the uniform object of oled luminance.
The driving method optical touch circuit of the present invention of the present embodiment had both had in-cell fixed point touch function, having again can the driving Presentation Function of compensating threshold voltage, thus achieves the integration of in-cell touch function and AMOLED pixel driver Presentation Function.Prior art owing to adopting two circuit be provided separately (for detecting touch, another is for driving), thus causes complex circuit designs, and easily produces interference between the signal of two circuit.Additionally by employing timesharing drive principle, after determining touch position coordinates, carry out threshold voltage compensation, the cut-in voltage of the drive current of driving tube and the threshold voltage of driving tube and OLED is had nothing to do, thus reaches the consistent of electric current.And then achieve brightness uniformity and the reliability of display screen
Obviously, those skilled in the art can make various changes and modifications embodiments of the invention under the premise without departing from the spirit and scope of the present invention.Scope of the present invention is limited by claims and equivalent thereof.