TWM493128U - Pixel units and driving circuits - Google Patents

Abstract

A pixel unit is provided, comprising a light emitting element and a driving circuit. The driving circuit comprises a first transistor, a first switch, a first capacitor and a control module. The first switch has a first terminal applied to receive a data voltage, a second terminal coupled to a gate of the first transistor and a gate applied to receive a first control signal. The first capacitor coupled to the gate of the first transistor. The control module coupled to a second terminal of the first transistor, the first capacitor and the light emitting element, and the control module is received a first control signal. In addition, the control module determines whether or not to make the voltage of the second terminal of the first transistor equal to the difference between the data voltage and the threshold voltage of the first transistor according to at least the first control signal. The control module further determines whether or not to make the first transistor generate a driving current, which is related to the data voltage, according to the voltage between the gate and the second terminal of the first transistor.

Description

Pixel unit and drive circuit

The present invention relates to a display system, and more particularly to a pixel unit and a driving circuit in a display system.

Nowadays, the use of light-emitting elements such as light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs) as light sources has become a fairly common application. The brightness of the light-emitting element is determined according to the driving current flowing therethrough. Therefore, for a driving circuit for driving the light-emitting element, the characteristics of the transistor and the power supply voltage for generating the driving current are It often has the greatest influence on the luminescent properties of the luminescent element.

For the transistor that generates the driving current, because of the uniformity problem in the process, a panel composed of a plurality of light-emitting elements and corresponding driving circuits, wherein each of the transistors for generating a driving current has a criticality The voltages are different, resulting in a difference in drive current. In addition, with long-term operation and use, each of the transistors for generating the driving current has different degrees of deterioration, and the degree of offset of the threshold voltage is also inconsistent, which also causes a difference in driving current. These will result in unequal drive currents under the same data registration, so that the panels composed of these light-emitting elements and corresponding drive circuits exhibit uneven brightness or imprinting.

On the other hand, for the power supply voltage that generates the drive current, In a panel composed of a plurality of light-emitting elements and corresponding driving circuits, a plurality of signal lines providing the power supply voltage have wire resistances, so that the power supply voltage of each driving circuit has a different degree of attenuation effect (IR-drop), As a result, the driving currents of the driving circuits are reduced to different degrees, and the panel composed of the light-emitting elements and the corresponding driving circuits also exhibits uneven brightness.

The purpose of the present invention is to provide a pixel unit and a driving circuit that are not affected by the threshold voltage of the transistor that generates the driving current and the power supply voltage attenuation effect.

The present pixel unit includes a driving circuit and a light emitting element having a first end and a second end. The driving circuit includes a first transistor, a first switch, a first capacitor, and a control module.

The first transistor includes a first end, a second end, and a control end. The first switch includes a first end receiving a data voltage, a second end electrically connected to the control end of the first transistor, and a control end receiving a first control signal, and determining according to the control of the first control signal Whether to output the data voltage to the control terminal of the first transistor. The first capacitor includes a first end electrically connected to the control end of the first transistor, and a second end.

The control module is electrically connected between the second end of the first transistor, the second end of the first capacitor, and the first end of the light emitting element, and receives the first control signal, and the control module controls according to the first control signal, Determining whether the voltage change of the control terminal of the first transistor follows the voltage change of the second terminal of the first transistor, so that the first transistor generates a driving current related to the data voltage according to the voltage across the control terminal and the second terminal.

The creation is generated by the control module based on at least the first control signal The driving current of the data voltage is not affected by the threshold voltage of the first transistor and the first power source voltage and the second power source voltage.

71~75‧‧‧ drive circuit

81~85‧‧‧Control Module

91~95‧‧‧Lighting elements

C1‧‧‧First Capacitor

C2‧‧‧second capacitor

DATA‧‧‧ data voltage

P1‧‧‧Reset phase

P2‧‧‧ Compensation phase

P3‧‧‧ planning stage

P4‧‧‧Lighting stage

S1‧‧‧ first control signal

S2‧‧‧ second control signal

S3‧‧‧ third control signal

SW1‧‧‧ first switch

SW2‧‧‧second switch

SW3‧‧‧ third switch

SW4‧‧‧fourth switch

T1‧‧‧first transistor

VSS‧‧‧First supply voltage

VDD‧‧‧second supply voltage

V _GL ‧‧‧ reference potential

Vo‧‧‧ first voltage value

Vdata‧‧‧second voltage value

1 is a circuit diagram illustrating a first preferred embodiment of the present pixel unit.

Figure 2 is a timing diagram, and Figure 1 illustrates the first preferred embodiment.

Figure 3 is a circuit diagram showing the aspect of the first preferred embodiment in a reset phase.

Figure 4 is a circuit diagram showing the aspect of the first preferred embodiment in a compensation phase.

Figure 5 is a circuit diagram illustrating the aspect of the first preferred embodiment in a planning phase.

Figure 6 is a circuit diagram showing the aspect of the first preferred embodiment in a lighting phase.

Figure 7 is a circuit diagram showing a second preferred embodiment of the present pixel unit.

Figure 8 is a timing diagram, and Figure 7 illustrates the second preferred embodiment.

Figure 9 is a circuit diagram showing a third preferred embodiment of the present pixel unit.

Fig. 10 is a timing chart, and Fig. 9 illustrates the third preferred embodiment.

Figure 11 is a circuit diagram showing a fourth preferred embodiment of the present pixel unit.

Fig. 12 is a timing chart, and Fig. 11 illustrates the fourth preferred embodiment.

Figure 13 is a circuit diagram showing a fifth preferred embodiment of the present pixel unit.

Fig. 14 is a timing chart, and Fig. 13 illustrates the fifth preferred embodiment.

Referring to FIG. 1, a first preferred embodiment of the present pixel unit includes a light-emitting element 91 and a driving circuit 71. The light-emitting element 91 has a first end and a second end, and the driving circuit 71 includes a first The transistor T1, a first switch SW1, a first capacitor C1, and a control mode Group 81, and a fourth switch SW4.

The first transistor T1 includes a first end, a second end, and a control end. The first switch SW1 includes a first end receiving a data voltage DATA, a second end electrically connected to the control end of the first transistor T1, and a control end receiving a first control signal S1, and according to the first control signal The control of S1 determines whether to output the data voltage DATA to the control terminal of the first transistor T1. The first capacitor C1 includes a first end electrically connected to the control end of the first transistor T1, and a second end.

The control module 81 is electrically connected between the second end of the first transistor T1, the second end of the first capacitor C1, and the first end of the light-emitting element 91, and receives the first control signal S1, and the control module 81 is based at least according to The control of the first control signal S1 determines whether the voltage change at the control terminal of the first transistor T1 follows the voltage change of the second terminal of the first transistor T1, so that the first transistor T1 is based on the control terminal of the first transistor T1. The voltage across the second end produces a drive current associated with the data voltage DATA.

The control module 81 includes a second capacitor C2, a second switch SW2, and a third switch SW3. The second capacitor C2 has a first end electrically connected to the second end of the first capacitor C1 and a second end electrically connected to the second end of the first transistor T1. The second switch SW2 has a first end electrically connected to the second end of the first capacitor C1, a second end receiving the first power supply voltage VSS, and a control end receiving the first control signal S1, and according to the first control The control of signal S1 switches between conduction and non-conduction. The third switch SW3 has a first end electrically connected to the second end of the first transistor T1, a second end electrically connected to the first end of the light emitting element 91, and a control end receiving the second control signal S2, and according to The control of the second control signal S2 switches between conduction and non-conduction.

The fourth switch SW4 includes a first end receiving a second power voltage VDD, A second end of the first end of the first transistor T1 is electrically connected to the second end of the first transistor T1, and a control terminal of the third control signal S3 is received, and is switched between conducting and non-conducting according to the control of the third control signal S3.

The control terminal of the first transistor T1 is defined as point A, the second end of the first capacitor C1 is point B, and the second end of the first transistor is point C.

In this embodiment, the light-emitting element 91 is an organic light-emitting diode, and the first transistor T1, the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 can be any N-type transistor ( NMOS) to achieve.

Referring to Figure 2, there is a timing diagram, and Figure 1 illustrates the first preferred embodiment. The pixel unit operates according to the first control signal S1, the second control signal S2, and the third control signal S3 in a reset phase P1, a compensation phase P2, a planning phase P3, and an illumination phase P4, and is convenient for description. In the following illustration, the fork symbol is used to indicate that the switch is not conducting.

Figure 3 is a circuit diagram showing the aspect of the first preferred embodiment in a reset phase P1. Referring to FIG. 2 and FIG. 3, in the reset phase P1, the first control signal S1 is at a high potential, the first switch SW1 and the second switch SW2 are turned on, the second control signal S2 is at a high potential, and the third switch SW3 is turned on. The third control signal S3 is at a low potential, so that the fourth switch SW4 is not turned on. The data voltage DATA is output to the control terminal of the first transistor T1 via the first switch SW1, and the voltage value is a first voltage value Vo, so that the voltage V _A at point _A is Vo, and the voltage V _B at point _B is VSS, C. The voltage of the point V _C is close to VSS.

Figure 4 is a circuit diagram showing the aspect of the first preferred embodiment in a compensation phase P2. Referring to FIG. 2 and FIG. 4, in the compensation phase P2, the first control signal S1 is at a high potential, the first switch SW1 and the second switch SW2 are turned on, and the second control signal S2 is at a low potential, so that the third switch SW3 is not turned on. The third control signal S3 is at a high potential to turn on the fourth switch SW4. The data voltage DATA is output to the control terminal of the first transistor T1 via the first switch SW1, and the voltage value is the first voltage value Vo, and the fourth switch SW4 inputs the second power voltage VDD to the first end of the first transistor T1. And the first transistor T1 charges the second end of the first transistor T1 to a difference between the first voltage value Vo and the threshold voltage V _TH,1 of the first transistor T1 according to the first voltage value Vo, so that the first transistor A transistor T1 is thus turned off, and the voltage V _A at point _A is Vo, the voltage V _B at point _B is VSS, and the voltage V _C at point _C is Vo-V _TH,1 .

Figure 5 is a circuit diagram showing the aspect of the first preferred embodiment in a planning phase P3. Referring to FIG. 2 and FIG. 5, in the planning phase P3, the first control signal S1 is high, the first switch SW1 and the second switch SW2 are turned on, and the second control signal S2 is low, so that the third switch SW3 is not turned on. The third control signal S3 is at a low potential, so that the fourth switch SW4 is not turned on. The magnitude of the data voltage DATA outputted to the control terminal of the first transistor T1 is a second voltage value Vdata such that the voltage V _A at point _A is Vdata. Since the second switch SW2 is turned on and the second terminal thereof receives the first power supply voltage VSS, the voltage V _B at point _B is VSS. Since the fourth switch SW4 is not turned on, even if the voltage difference between the control terminal and the second terminal of the first transistor T1 is greater than the threshold voltage V _TH,1 , the C point cannot be charged, and because the second switch SW2 is turned on, the first capacitor C1 and the second capacitor C2 do not have a coupling effect, so that the voltage at point C can be kept the same as the compensation state P2, that is, V _C is Vo-V _TH,1 . The voltage across the first capacitor C1 and the second capacitor C2 at the planning stage P3 is V _A - V _B = Vdata - VSS, V _B - V _C = VSS - (Vo - V _{TH, 1} ), respectively.

Figure 6 is a circuit diagram showing the aspect of the first preferred embodiment in an illumination phase P4. Referring to FIG. 2 and FIG. 6, in the light-emitting phase P4, the first control signal S1 is at a low potential, so that the first switch SW1 and the second switch SW2 are not turned on, and the second control signal S2 is at a high potential, so that the third switch SW3 is turned on. The third control signal S3 is at a high potential to turn on the fourth switch SW4. The driving current flowing to the light-emitting element 91 via the fourth power supply voltage VDD through the fourth switch SW4, the first transistor T1, and the third switch SW3 causes the voltage V _C at the point _{C to} be the first power supply voltage VSS and the light-emitting element 91 to be turned on. The voltage across the time, that is, V _C is VSS+V _OLED , and the V _OLED is the voltage across when the light-emitting element 91 is turned on. Since the first switch SW1 and the second switch SW2 are not turned on, the voltage across the first capacitor C1 and the second capacitor C2 in the light-emitting phase is kept the same as the planning phase P3, that is, the voltage across the first capacitor C1 is V _A - V _B = Vdata - VSS, and the voltage across the second capacitor C2 is V _B - V _C = VSS - (Vo - V _{TH, 1} ). From the voltage across the C point, the first capacitor C1 and the second capacitor C2, the voltage V _B at point _B is VSS+(VSS+V _OLED )-(Vo-V _TH,1 ), and the voltage V _A at point _A is V _data + (VSS + V _OLED ) - (Vo - V _{TH, 1} ).

The first transistor T1 of the light-emitting phase P4 generates a driving current of K ( V _{GS , 1} - V _{TH , 1} ) ² = K ( V ) according to the voltages of the control terminal and the second terminal, that is, the voltages at points A and C. _A - V _C - V _{TH ,1} ) ² = K (( Vdata +( VSS + V _OLED )-( V _O - V _{TH ,1} ))-( VSS + V _OLED )- V _{TH ,1} ) ² = K ( Vdata - V _O ) ² ---Formula 1 where K is the transistor constant.

It can be seen from Equation 1 that the driving current is related to the difference between the second voltage value Vdata of the data voltage DATA and the first voltage value Vo. Compared with the prior art, in the panel composed of the plurality of light-emitting elements 91 and the corresponding driving circuit 71, the driving current of the present invention is independent of the threshold voltage V _{TH,1 of the} first transistor T1, and thus will not Because the process uniformity of the first transistor T1 is different or the degree of degradation is different, the threshold voltage V _TH,1 of the first transistor T1 of different pixel units is different, so that the driving current is not at the same data voltage DATA. Equal phenomenon. In addition, each driving current is not related to the first power voltage VSS and the second power voltage VDD, that is, even if a plurality of signal lines providing the first power voltage VSS and the second power voltage VDD have wire resistance, each The first power supply voltage VSS and the second power supply voltage VDD of the drive circuit 71 have different attenuation effects, and the drive current of each drive circuit 71 does not decrease to a different extent. In other words, the driving current of the pixel unit of the present invention is not affected by the threshold voltage V _TH,1 of the first transistor T1, the first power voltage VSS, and the second power voltage VDD, so that the pixel is The panel formed by the unit has a significant improvement in the problem of uneven brightness or branding.

Referring to FIG. 7, a schematic circuit diagram illustrating a second preferred embodiment of the present pixel unit is substantially similar to the first preferred embodiment. The difference is that the driving circuit 72 includes a fourth switch SW4. The fourth switch SW4 includes a first end receiving the third control signal S3, a second end electrically connected to the first end of the first transistor T1, and a control end receiving the second control signal S2, and according to the The control of the second control signal S2 switches between conduction and non-conduction.

The control module 82 omits the third switch SW3 (see FIG. 1), and the second capacitor C2 has a first end electrically connected to the second end of the first capacitor C1, and electrically connected to the second end of the first transistor T1, respectively. A second end of the first end of the light emitting element 92.

Figure 8 is a timing diagram, and Figure 7 illustrates the second preferred embodiment. Referring to FIG. 7 and FIG. 8, in the reset phase P1, the second control signal S2 is at a high potential, the fourth switch SW4 is turned on, and the third control signal S3 is a reference potential V _GL , so that the charge at the C point can pass through the first A transistor T1 and a fourth switch SW4 flow out to reach the reference potential V _GL faster. At this time, the voltages of points A and B are the same as in the first preferred embodiment, that is, V _A is Vo and V _B is VSS.

During the compensation phase P2, the second control signal S2 is at a high potential, causing the fourth switch SW4 to be turned on, and the voltage across the second end of the first transistor T1 and the second end of the light-emitting element 92 is less than the turn-on voltage of the light-emitting element 92. At this time, the voltages of points A, B, and C are the same as in the first preferred embodiment, that is, V _A is Vo, V _B is VSS, and V _C is Vo-V _TH,1 .

In the planning phase P3, the second control signal S2 is at a low potential, so that the fourth switch SW4 is not turned on, and the third control signal S3 is at a high potential. Since the states of the first switch SW1, the second switch SW2, and the fourth switch SW4 are the same as the planning phase P3 of the first preferred embodiment, the voltage across the first capacitor C1 and the second capacitor C2 is also preferably the first. The planning phase P3 of the embodiment is the same, respectively V _A - V _B = Vdata - VSS, V _B - V _C = VSS - (Vo - V _{TH, 1} ), and the voltage at point C is also the same as the first preferred embodiment. The same, that is, V _C is Vo-V _TH,1 .

In the light-emitting phase P4, the second control signal S2 is at a high potential, the fourth switch SW4 is turned on, and the third control signal S3 is at a high potential. Similar to the first preferred embodiment, the driving current flows from the third control signal S3 to the light-emitting element 92 via the fourth switch SW4 and the first transistor T1, so that the voltage V _C at the point _C is the first power supply voltage VSS plus the light emission. The voltage across the element 92 when it is turned on, that is, V _C is VSS+V _OLED , and the V _OLED is the voltage across when the light-emitting element 92 is turned on. As in the first preferred embodiment, since the first switch SW1 and the second switch SW2 are not turned on, the voltage across the first capacitor C1 and the second capacitor C2 of the light-emitting phase P4 is maintained the same as the planning phase P3, that is, the first The voltage across a capacitor C1 is V _A - V _B = Vdata - VSS, and the voltage across the second capacitor C2 is V _B - V _C = VSS - (Vo - V _{TH, 1} ). From the voltage across the C point, the first capacitor C1 and the second capacitor C2, the voltage V _B at point _B is VSS+(VSS+V _OLED )-(Vo-V _TH,1 ), and the voltage V _A at point _A is _{vdata + (VSS + V OLED)} - (Vo-V TH, 1).

The voltage of the first transistor T1 of the light-emitting phase P4 is the same as that of the first preferred embodiment according to the voltages of the control terminal and the second terminal, that is, the voltages of the A and C points. Therefore, the generated driving current is also the same, that is, The same advantages as the first preferred embodiment.

Referring to FIG. 9, a schematic circuit diagram illustrating a third preferred embodiment of the present pixel unit is substantially similar to the second preferred embodiment. The difference is that the driving power is The path 73 omits the fourth switch SW4 (see FIG. 7) and the third control signal S3 (see FIG. 7), and the first end of the first transistor T1 receives the second control signal S2.

Fig. 10 is a timing chart, and Fig. 9 illustrates the third preferred embodiment. Referring to FIG. 9 and FIG. 10, in the reset phase P1, the second control signal S2 is the reference potential V _GL , so that the charge of the C point can flow out through the first transistor T1 to reach the reference potential V _GL faster. At this time, the voltages of points A and B are the same as in the second preferred embodiment, that is, V _A is Vo and V _B is VSS.

In the compensation phase P2, the voltages of points A, B, and C are the same as in the second preferred embodiment, that is, V _A is Vo, V _B is VSS, and V _C is Vo-V _TH,1 .

In the planning phase P3, the second control signal S2 is at a high potential, and the charge at the C point can flow in through the first transistor T1, so that the voltage V _C at the point _C is Vo-V _{TH, 1} + dv, and dv is the charge inflow C During the process of the dot, a variable that increases with time increases, and dv is related to the mobility of the first transistor T1. The voltage across the first capacitor C1 and the second capacitor C2 at the planning stage P3 is V _A - V _B = Vdata - VSS, V _B - V _C = VSS - (Vo - V _{TH, 1} + dv), and The voltage across the second end of the transistor T1 and the second end of the light-emitting element 93 is smaller than the turn-on voltage of the light-emitting element 93.

In the illuminating phase P4, the second control signal S2 is at a high potential. Similarly to the second preferred embodiment, the driving current flows from the second control signal S2 to the illuminating element 93 via the first transistor T1, so that the voltage V at the point C is _C is the first power supply voltage VSS plus the voltage across when the light-emitting element 93 is turned on, that is, V _C is VSS+V _OLED , and V _OLED is the voltage across when the light-emitting element 93 is turned on. As in the second preferred embodiment, since the first switch SW1 and the second switch SW2 are not turned on, the voltage across the first capacitor C1 and the second capacitor C2 in the light-emitting phase is kept the same as the planning phase P3, that is, the first The voltage across the capacitor C1 is V _A - V _B = Vdata - VSS, and the voltage across the second capacitor C2 is V _B - V _C = VSS - (Vo - V _{TH, 1} + dv). From the voltage at point C, the voltage across the first capacitor C1 and the second capacitor C2, the voltage V _B at point _B is VSS+(VSS+V _OLED )-(Vo-V _TH,1 +dv), the voltage at point A. V _A is Vdata+(VSS+V _OLED )-(Vo-V _{TH, 1} +dv).

The first transistor T1 of the light-emitting phase P4 generates a driving current of K ( V _{GS , 1} - V _{TH , 1} ) ² = K ( V ) according to the voltages of the control terminal and the second terminal, that is, the voltages at points A and C. _A - V _C - V _{TH , 1} ) ² = K (( Vdata + ( VSS + V _OLED ) - ( V _O - V _{TH , 1} + dv )) - ( VSS + V _OLED ) - V _{TH , 1} ) ² _{= K (Vdata - V O -} dv) 2 --- seen from formula 2 formula 2, the driving current of the pixel units is not present in addition to the creation of a first transistor T1, the threshold voltage V _{TH, 1,} the first power supply The influence of the voltage VSS and the second power supply voltage VDD can also compensate for the difference in mobility of the first transistor T1. When the mobility of the first transistor T1 is larger, dv will be smaller. Conversely, as the mobility of the first transistor T1 is smaller, dv will be larger.

Referring to FIG. 11, which is a circuit diagram, illustrates a fourth preferred embodiment of the present pixel unit, which is substantially similar to the first preferred embodiment, except that the driving circuit 74 omits the fourth switch SW4 ( Referring to FIG. 1), the first end of the first transistor T1 receives the second control signal S2. The control terminal of the third switch SW3 of the control module 84 does not receive the second control signal S2, but receives the third control signal S3, and switches between conduction and non-conduction according to the control of the third control signal S3.

Fig. 12 is a timing chart, and Fig. 11 illustrates the fourth preferred embodiment. Referring to FIG. 11 and FIG. 12, in the reset phase P1, the second control signal S2 is a reference potential V _GL , and the third control signal S3 is low, so that the third switch S3 is not turned on, and the charge at the C point can be The first transistor T1 flows out to reach the reference potential V _GL . At this time, the voltages of points A and B are the same as in the first preferred embodiment, that is, V _A is Vo and V _B is VSS.

In the compensation phase P2, the second control signal S2 is at a high potential, and the third control signal S3 is at a low potential, so that the third switch S3 is not turned on. At this time, the voltages of points A, B, and C are the same as in the first preferred embodiment, that is, _VA is Vo, V _B is VSS, and V _C is Vo-V _TH,1 .

In the planning phase P3, the second control signal S2 is at a high potential, the third control signal S3 is at a low potential, so that the third switch S3 is not turned on, and the charge at the C point can flow in through the first transistor T1, so that the voltage at the point C is V _C is Vo-V _{TH, 1} + dv, and dv is a variable that increases as time passes through the point C, and dv is related to the mobility of the first transistor T1. The voltage across the first capacitor C1 and the second capacitor C2 at the planning stage P3 is V _A - V _B = Vdata - VSS, V _B - V _C = VSS - (Vo - V _{TH, 1} + dv), respectively.

In the illuminating phase P4, the second control signal S2 is at a high potential, and the third control signal S3 is at a high potential, causing the third switch S3 to be turned on. Similar to the first preferred embodiment, the driving current is controlled by the second control signal S2. A transistor T1 and a third switch SW3 flow to the light-emitting element 94 such that the voltage V _C at the point _C is the first power supply voltage VSS plus the voltage across when the light-emitting element 94 is turned on, that is, V _C is VSS+V _OLED , V _OLED It is the voltage across when the light-emitting element 94 is turned on. As in the first preferred embodiment, since the first switch SW1 and the second switch SW2 are not turned on, the voltage across the first capacitor C1 and the second capacitor C2 of the light-emitting phase P4 is maintained the same as the planning phase P3, that is, the first The voltage across a capacitor C1 is V _A - V _B = Vdata - VSS, and the voltage across the second capacitor C2 is V _B - V _C = VSS - (Vo - V _{TH, 1} + dv). From the voltage at point C, the voltage across the first capacitor C1 and the second capacitor C2, the voltage V _B at point _B is VSS+(VSS+V _OLED )-(Vo-V _TH,1 +dv), the voltage at point A. V _A is Vdata+(VSS+V _OLED )-(Vo-V _{TH, 1} +dv).

The first transistor T1 of the light-emitting phase P4 generates a driving current of K ( V _{GS , 1} - V _{TH , 1} ) ² = K ( V ) according to the voltages of the control terminal and the second terminal, that is, the voltages at points A and C. _A - V _C - V _{TH , 1} ) ² = K (( Vdata + ( VSS + V _OLED ) - ( V _O - V _{TH , 1} + dv )) - ( VSS + V _OLED ) - V _{TH , 1} ) ² = K ( Vdata - V _O - dv ) ² --- Equation 3 It can be known from Equation 3 that the driving current of the pixel unit of the present invention is not affected by the threshold voltage V _{TH of the} first transistor T1 _, and the first power source The influence of the voltage VSS and the second power supply voltage VDD can also compensate for the difference in mobility of the first transistor T1. When the mobility of the first transistor T1 is larger, dv will be smaller. Conversely, as the mobility of the first transistor T1 is smaller, dv will be larger.

Referring to Figure 13, there is shown a circuit diagram illustrating a fifth preferred embodiment of the present pixel unit, substantially similar to the fourth preferred embodiment, with the following differences:

The third switch SW3 of the control module 85 is a P-type transistor (PMOS), and the control terminal of the third switch SW3 does not receive the third control signal S3, but receives the first control signal S1 according to the first control signal S1. Control, switching between conduction and non-conduction.

Fig. 14 is a timing chart, and Fig. 13 illustrates the fifth preferred embodiment. Referring to FIG. 13 and FIG. 14, in the reset phase P1, the compensation phase P2, and the planning phase P3, the first control signal S1 is at a high potential, so that the third switch S3 is not turned on. In the light-emitting phase P4, the first control signal S1 is at a low potential, and the third switch S3 is turned on. The voltages at points A, B, and C of the reset, compensation, planning, and illumination stages P1 to P4 are the same as those of the fourth preferred embodiment, and therefore, the drive current generated by the first transistor T1 is also There are advantages of the fourth preferred embodiment.

It can be seen from the above embodiments that the driving current related to the data voltage DATA can be generated by the control module according to at least the first control signal S1, without being affected by the threshold voltage V _TH,1 of the first transistor T1 and the first power voltage. The effect of VSS and the second supply voltage VDD. That is, there is no difference in the threshold voltage of the driving transistor of the different pixel units due to the uniformity of the process of driving the transistor (the first transistor T1 in the above embodiment), and the influence of the power supply voltage attenuation effect. As a result, when the same data voltage is given, there is a phenomenon that the corresponding driving currents are not equal, thereby improving the uneven brightness or branding of the panel composed of the pixel units.

71‧‧‧Drive circuit

81‧‧‧Control Module

91‧‧‧Lighting elements

C1‧‧‧First Capacitor

C2‧‧‧second capacitor

DATA‧‧‧ data voltage

S1‧‧‧ first control signal

S2‧‧‧ second control signal

S3‧‧‧ third control signal

SW1‧‧‧ first switch

SW2‧‧‧second switch

SW3‧‧‧ third switch

SW4‧‧‧fourth switch

T1‧‧‧first transistor

VSS‧‧‧First supply voltage

VDD‧‧‧second supply voltage

Claims (11)

A pixel unit includes a light-emitting element having a first end and a second end, wherein the pixel unit further comprises: a driving circuit, comprising: a first transistor, including a first end a second end and a control end; a first switch comprising a first end receiving a data voltage, a second end electrically connected to the control end of the first transistor, and a first receiving a first control signal a control terminal, and determining, according to the control of the first control signal, whether to output the data voltage to the control end of the first transistor; a first capacitor comprising a first end electrically connected to the control end of the first transistor, And a second terminal; and a control module electrically connected between the second end of the first transistor, the second end of the first capacitor, and the first end of the light emitting element, and receiving the first control a signal, the control module determining, according to the control of the first control signal, whether to cause a voltage change of the control terminal of the first transistor to follow a voltage change of the second end of the first transistor, so that the first transistor is configured according to the voltage First transistor Voltage across the control terminal and the second terminal, generating a driving current related to the voltage data. According to the pixel unit of claim 1, wherein the control module comprises: a second capacitor having a first end electrically connected to the second end of the first capacitor and a second end electrically connected to the second end of the first transistor; a second switch having an electrical connection to the first capacitor a first end of the second end, a second end receiving a first power supply voltage, and a control end receiving the first control signal, and switching between conducting and non-conducting according to the control of the first control signal And a third switch having a first end electrically connected to the second end of the first transistor, a second end electrically connected to the first end of the light emitting element, and a control end receiving the second control signal And switching between conduction and non-conduction according to the control of the second control signal. The pixel unit of claim 2, wherein the driving circuit further comprises a fourth switch, the fourth switch comprising a first end receiving a second power voltage, and electrically connecting the first transistor a second end of one end, and a control end receiving a third control signal, and switching between conducting and non-conducting according to the control of the third control signal, the pixel unit according to the first control signal, The second control signal and the third control signal are operated in a reset phase, a compensation phase, a planning phase, and an illumination phase: during the reset phase, the first control signal causes the first switch and the second switch Turning on, the second control signal turns on the third switch, the third control signal makes the fourth switch non-conductive, and the data voltage is passed through the first The switch is output to the control end of the first transistor, and the voltage value is a first voltage value; during the compensation phase, the first control signal turns on the first switch and the second switch, and the second control signal enables The third switch is not turned on, the third control signal turns on the fourth switch, the fourth switch inputs the second power voltage to the first end of the first transistor, and the first transistor is according to the first a voltage value charging the second end of the first transistor to a difference between the first voltage value and a threshold voltage of the first transistor; during the planning phase, the first control signal causes the first switch to The second switch is turned on, the second control signal makes the third switch non-conducting, the third control signal makes the fourth switch non-conducting, and the data voltage is output to the control end of the first transistor is a second voltage And the first control signal causes the first switch and the second switch to be non-conducting, and the second control signal turns on the third switch, the third control signal turns on the fourth switch, The first transistor generates the phase The difference between the driving current of the first voltage value and the second voltage value. The pixel unit of claim 1, wherein the control module comprises: a second capacitor having a first end electrically connected to the second end of the first capacitor, and electrically connecting the first transistor respectively a second end and a second end of the first end of the light emitting element; a second switch having a first end electrically connected to the second end of the first capacitor, a second end receiving a first power supply voltage, and a control end receiving the first control signal, and according to the first The control of the control signal switches between conduction and non-conduction. The pixel unit of claim 4, wherein the driving circuit further comprises a fourth switch, the fourth switch comprising a first end receiving a third control signal, and electrically connecting the first transistor a second end of one end, and a control end receiving a second control signal, and switching between conducting and non-conducting according to the control of the second control signal, the pixel unit according to the first control signal, The second control signal and the third control signal are operated in a reset phase, a compensation phase, a planning phase, and an illumination phase: during the reset phase, the first control signal causes the first switch and the second switch Turning on, the second control signal turns on the fourth switch, the third control signal is low, so that the data voltage is output to the control end of the first transistor via the first switch, and the voltage value of the data voltage Is a first voltage value; in the compensation phase, the first control signal turns on the first switch and the second switch, and the second control signal turns on the fourth switch, the third control signal is high, And The first transistor charges the second end of the first transistor to a difference between the first voltage value and a threshold voltage of the first transistor according to the first voltage value; During the planning phase, the first control signal turns on the first switch and the second switch, the second control signal disables the fourth switch, the third control signal is high, and the data voltage is output to the The size of the control end of the first transistor T1 is a second voltage value; and during the lighting phase, the first control signal causes the first switch and the second switch to be non-conducting, and the second control signal causes the fourth switch Turning on, the third control signal is high, and the first transistor generates the driving current related to the difference between the first voltage value and the second voltage value. The pixel unit of claim 4, wherein the first end of the first transistor of the driving circuit receives a second control signal, and the pixel unit is based on the first control signal and the second control signal. a reset phase, a compensation phase, a planning phase, and an illumination phase operation: during the reset phase, the first control signal turns on the first switch and the second switch, and the second control signal is low The data voltage is output to the control end of the first transistor via the first switch, and the voltage value of the data voltage is a first voltage value; during the compensation phase, the first control signal makes the first The switch is electrically connected to the second switch, the second control signal is high, and the first transistor charges the second end of the first transistor to the first voltage value and the first power according to the first voltage value The difference in the threshold voltage of the crystal; In the planning phase, the first control signal turns on the first switch and the second switch, the second control signal is high, and the data voltage is output to the control end of the first transistor is a second voltage And the first control signal causes the first switch and the second switch to be non-conducting, and the second control signal is high, the first transistor generating the correlation with the first voltage value and The drive current of the difference in the second voltage value. The pixel unit of claim 1, wherein the first end of the first transistor of the driving circuit receives a second control signal, the control module includes: a second capacitor having an electrical connection a first end of the second end of the capacitor, and a second end electrically connected to the second end of the first transistor; a second switch having a first end electrically connected to the second end of the first capacitor, receiving a first end a second end of the first power supply voltage, and a control end receiving the first control signal, and switching between conducting and non-conducting according to the control of the first control signal; and a third switch having an electrical connection a first end of the second end of the first transistor, a second end electrically connected to the first end of the light emitting element, and a control end receiving a third control signal, and according to the control of the third control signal, Switch between conduction and non-conduction. The pixel unit of claim 7, wherein the first control signal, the second control signal, and the third control signal are operated in a reset phase, a compensation phase, a planning phase, and an illumination phase During the reset phase, the first control signal turns on the first switch and the second switch, the third control signal disables the third switch, and the second control signal is low, so that the data voltage Outputting to the control end of the first transistor via the first switch, and the voltage value of the data voltage is a first voltage value; during the compensation phase, the first control signal causes the first switch and the second switch Turning on, the third control signal makes the third switch non-conductive, the second control signal is high, and the first transistor charges the second end of the first transistor to the first according to the first voltage value a difference between a voltage value and a threshold voltage of the first transistor; during the planning phase, the first control signal turns on the first switch and the second switch, and the third control signal disables the third switch The second The control signal is high, and the size of the data voltage outputted to the control end of the first transistor is a second voltage value; and in the light emitting phase, the first control signal makes the first switch and the second switch non-conductive The third control signal turns on the third switch, the second control signal is high, and the first transistor generates the driving current related to the difference between the first voltage value and the second voltage value. The pixel unit of claim 1, wherein the first end of the first transistor of the driving circuit receives a second control signal, the control module includes: a second capacitor having an electrical connection a first end of the second end of the capacitor, and a second end electrically connected to the second end of the first transistor; a second switch having a first end electrically connected to the second end of the first capacitor, receiving a first end a second end of the first power supply voltage, and a control end receiving the first control signal, and switching between conducting and non-conducting according to the control of the first control signal; and a third switch having an electrical connection a first end of the second end of the first transistor, a second end electrically connected to the first end of the light emitting element, and a control end receiving a third control signal, and according to the control of the first control signal, Switch between conduction and non-conduction. According to the pixel unit of claim 9, wherein, according to the first control signal and the second control signal, operating in a reset phase, a compensation phase, a planning phase, and an illumination phase: in the reset In the phase, the first control signal turns on the first switch and the second switch, and the third switch is not turned on, and the second control signal is low, so that the data voltage is output to the first via the first switch a control end of the transistor, and the voltage value of the data voltage is a first voltage value; During the compensation phase, the first control signal turns on the first switch and the second switch, and makes the third switch non-conductive, the second control signal is high, and the first transistor is according to the first The voltage value charges the second end of the first transistor to a difference between the first voltage value and a threshold voltage of the first transistor; during the planning phase, the first control signal causes the first switch to The second switch is turned on, and the third switch is not turned on, the second control signal is high, and the size of the data voltage outputted to the control end of the first transistor is a second voltage value; and during the light emitting phase, The first control signal causes the first switch and the second switch to be non-conducting, and the third switch is turned on, the second control signal is high, and the first transistor generates the first voltage value and the first The drive current of the difference between the two voltage values. A driving circuit, comprising: a first transistor, comprising a first end, a second end, and a control end; a first switch comprising a first end receiving a data voltage, the electric Connecting a second end of the control end of the first transistor, and receiving a control end of the first control signal, and determining, according to the control of the first control signal, whether to output the data voltage to the control of the first transistor a first capacitor, comprising a first end electrically connected to the control end of the first transistor, and a second end; a control module electrically connected between the second end of the first transistor and the second end of the first capacitor, and receiving the first control signal, the control module is controlled according to the first control signal, Determining whether the voltage change of the control terminal of the first transistor follows the voltage change of the second terminal thereof, so that the first transistor generates a driving current related to the data voltage according to the voltage across the control terminal and the second terminal.