TWI767353B - OLED pixel compensation circuit, OLED display and information processing device - Google Patents

Abstract

The present invention mainly discloses an OLED pixel compensation circuit, which is applied in an OLED display panel and includes N signal transmission lines and N voltage adjustment units. During a capacitor charging time interval, the voltage adjustment unit provides a grounding voltage to the second end of a voltage maintaining capacitor of a pixel circuit through the signal transmission line, so that the voltage maintaining capacitor is maintained at a voltage level through a display data signal. After charging, its first terminal has a capacitor terminal voltage. And, in a voltage maintenance time interval, the voltage adjustment unit provides an adjustment voltage to the second end of the voltage maintenance capacitor through the signal transmission line, so as to use the adjustment voltage to maintain the voltage at the capacitor end of the capacitor The voltage is adjusted to a driving voltage. By changing the way of adjusting the voltage, the leakage current of the pixel circuit and the voltage maintaining capacitor can be removed, so as to ensure that the OLED display panel will not cause the phenomenon of picture flicker during the process of displaying the image picture.

Description

OLED pixel compensation circuit, OLED display and information processing device

The present invention relates to the technical field of OLED displays, and more particularly, to an OLED pixel compensation circuit, which utilizes the technology of dynamically adjusting the driving voltage to remove the leakage current of the pixel circuit and the voltage maintaining capacitor, thereby ensuring that the OLED display panel is not able to display an image during the display. There will be no screen flickering during the process.

It is known that Organic Light-Emitting Diode (OLED) has the advantages of self-luminescence, high brightness, high contrast, wide viewing angle, power consumption, and high reaction rate, so it has been widely used in self-luminescence. The manufacture of display panels includes active OLED (ie, AMOLED) display panels and active OLED (ie, PMOLED) display panels.

FIG. 1 shows a block diagram of a conventional OLED display. As shown in FIG. 1, the OLED display 1a mainly includes: an OLED display panel 11a, a gate (column) driving circuit 12a, a source (row) driving circuit 13a, and a display controller 14a. The OLED display panel 11a includes N×M OLED sub-pixels 111a, N×M pixel circuits 112a, M source driving lines 11Sa, and N gate driving lines 11Ga. Moreover, each gate driving line 11Ga is coupled to M pixel circuits 112a along the column direction, and each source driving line 11Sa is coupled to N pixel circuits 112a along the row direction. FIG. 2 shows a block diagram of N pixel circuits in the i-th row of the OLED display panel of FIG. 1 . In the design of the conventional OLED display panel 11a, each of the OLED sub-pixels 111a is coupled to one of the pixel circuits 112a, wherein the pixel circuit 112a includes a driving current generating unit 1121a and at least one voltage maintaining capacitor 1122a .

3a, 3b and 3c show schematic diagrams of circuit operation of a conventional pixel circuit. As shown in FIG. 3a, in a capacitor charging time interval, the voltage maintaining capacitor 1122a is charged to the first voltage V1 through the display data signal V _DATA transmitted by the source driving line 11Sa. Further, as shown in FIG. 3b, in a voltage maintaining time interval, the voltage maintaining capacitor 1122a will maintain its terminal voltage at the first voltage V1; in this case, the first voltage V1 is used as a drive The voltage V _G is transmitted to the driving current generating unit 1121a, so that the driving current generating unit 1121a generates a driving current according to the driving voltage V _G to drive the OLED sub-pixel 111a to emit light.

It should be noted that the conventional driving current generating unit 1121a is composed of a plurality of thin film transistor (TFT) elements, and the process error often causes the threshold voltage values of the plurality of thin film transistor elements to be inconsistent. At the same time, the variation or drift of the threshold voltage caused by the process error will also cause the different two driving current generating units 1121a to have different I _OFF currents, and also cause the different two voltage maintaining capacitors 1122 to have different capacitance leakages. Therefore, as shown in FIG. 3c, in the voltage maintaining time interval, the terminal voltage of the voltage maintaining capacitor 1122a will be maintained at the first voltage V1 originally, but the leakage current of the voltage maintaining capacitor 1122 itself and the driving force The I _OFF current of the current generating unit 1121a causes the terminal voltage of the voltage maintaining capacitor 1122a to become V1+/-ΔV. Among them, △V=(I _OFF *T)/Cs. It should be understood that Cs is the capacitance value of the voltage maintaining capacitor 1122a, I _OFF is the leakage current of the voltage maintaining capacitor 1122 itself and/or the I _OFF current of the driving current generating unit 1121a, and T is the voltage maintaining capacitor 1122a at the voltage maintaining A voltage maintaining time elapsed in the time interval, and ΔV is the capacitance voltage variation of the voltage maintaining capacitor 1122a.

T)。因此，在沒有對I_OFF電流及/或電壓維持電容1122的漏電流進行適當補償的情況下，會導致OLED顯示面板11a在顯示影像畫面的過程中發生出現畫面閃爍(flicker)的現象。 FIG. 4 is a graph showing the voltage sustaining time of the voltage sustaining capacitor 1122a and the variation of the capacitor voltage. After completing the fabrication of a pixel circuit 112a including a driving current generating unit 1121a and at least one voltage maintaining capacitor 1122a by a semiconductor process, the I _OFF current of the driving current generating unit 1121 and the leakage current of the voltage maintaining capacitor 1122 are generally is the fixed value. Therefore, as shown in FIG. 4 , in the voltage maintaining time interval, the capacitance voltage change ΔV of the voltage maintaining capacitor 1122a is proportional to the elapsed voltage maintaining time (ΔV

T). Therefore, without proper compensation for the I _OFF current and/or the leakage current of the voltage sustaining capacitor 1122 , the OLED display panel 11a may cause a flicker phenomenon during the process of displaying an image.

It can be seen from the above description that there is an urgent need in the art for a new type of OLED pixel compensation circuit integrated in an OLED panel.

The main purpose of the present invention is to provide an OLED pixel compensation circuit, which is applied in an OLED display panel. In a capacitor charging time interval, the OLED pixel compensation of the present invention The circuit provides a ground voltage to the second end of a voltage maintaining capacitor of a pixel circuit, so that the first end of the voltage maintaining capacitor has a capacitor terminal voltage after being charged by a display data signal. And, in a voltage maintaining time interval, the OLED pixel compensation circuit of the present invention provides an adjustment voltage to the second end of the voltage maintaining capacitor, so as to use the adjustment voltage to adjust the voltage of the capacitor terminal of the voltage maintaining capacitor to a driving voltage. By changing the way of adjusting the voltage, the leakage current of the pixel circuit and the voltage maintaining capacitor can be removed, so as to ensure that the OLED display panel will not cause the phenomenon of picture flicker during the process of displaying the image picture.

In order to achieve the above object, the present invention proposes a first embodiment of the OLED pixel compensation circuit, which is applied to an OLED display including at least one display driver chip and an OLED display panel; wherein the OLED display panel includes N×M OLED sub-pixels and N×M pixel circuits, and each pixel circuit includes a driving current generating unit and a voltage maintaining capacitor coupled to the driving current generating unit with a first end thereof; The OLED pixel compensation circuit includes: N signal transmission lines, wherein each of the signal transmission lines is coupled to a second end of the M voltage maintaining capacitors in the same row; and N voltage adjustment units, wherein each The voltage adjustment unit has a first electrical terminal, a second electrical terminal and a third electrical terminal, the first electrical terminal is coupled to the signal transmission line, and the second electrical terminal is coupled to a ground terminal, and the third electrical terminal is coupled to a working voltage; wherein, in a capacitor charging time interval, the voltage adjustment unit provides a ground voltage to the second terminal of the voltage maintaining capacitor through the signal transmission line , after the voltage maintaining capacitor is charged by a display data signal, the first terminal of the capacitor has a capacitor terminal voltage; wherein, in a voltage maintaining time interval, the voltage adjustment unit provides a voltage through the signal transmission line The voltage is adjusted to the second end of the voltage maintaining capacitor, so that the voltage of the capacitor terminal of the voltage maintaining capacitor is adjusted to a driving voltage by using the adjustment voltage.

In one embodiment, each of the voltage adjustment units includes: a current source unit having a first end and a second end coupled to the working voltage; a current sink unit having a first end and a second end coupled to the working voltage; a second end of the ground terminal; a first switch, having a first electrical terminal coupled to the first terminal of the current source unit, a second electrical terminal, and a control terminal coupled to a first control signal; a second switch, having a first electrical terminal coupled to the first terminal of the current tank unit, a second electrical terminal, and a control terminal coupled to a second control signal, and the second electrical terminal of the first switch The electrical terminal and the second electrical terminal of the second switch are coupled to a common contact; and a resistor, a first end of which is coupled to the common contact, and a second end of which is coupled to the ground terminal .

In a possible embodiment, in the voltage maintaining time interval, the second switch is turned on according to the control of the second control signal and the first switch is turned off according to the control of the first control signal, so that the current source is The unit provides a first current flowing through the resistor, so that the first end of the resistor has a resistor terminal voltage as the adjustment voltage.

In another possible embodiment, in the voltage maintaining time interval, the first switch is turned on according to the control of the first control signal and the second switch is turned off according to the control of the second control signal, so that the current The tank unit provides a second current flowing through the resistor, so that the first end of the resistor has a resistor terminal voltage as the adjustment voltage.

In order to achieve the above object, the present invention proposes a second embodiment of the OLED pixel compensation circuit, which is applied to an OLED display including at least one display driver chip and an OLED display panel; wherein the OLED display panel includes N×M OLED sub-pixels and N×M pixel circuits, and each pixel circuit includes a driving current generating unit and a voltage maintaining capacitor coupled to the driving current generating unit with a first end thereof; The OLED pixel compensation circuit includes: N×M voltage adjustment units, wherein each of the voltage adjustment units has a first electrical terminal, a second electrical terminal and a third electrical terminal, the first electrical terminal The electrical terminal is coupled to a second terminal of the voltage maintaining capacitor, the second electrical terminal is coupled to a ground terminal, and the third electrical terminal is coupled to a working voltage; wherein, in a capacitor charging time interval, The voltage adjustment unit provides a ground voltage to the second end of the voltage maintaining capacitor, so that the first end of the voltage maintaining capacitor has a capacitor terminal voltage after being charged by a display data signal; Wherein, in a voltage maintenance time interval, the voltage adjustment unit provides an adjustment voltage to the second end of the voltage maintenance capacitor, so as to use the adjustment voltage to adjust the voltage of the capacitor terminal of the voltage maintenance capacitor to a drive Voltage.

In one embodiment, each of the voltage adjustment units includes: a current source unit having a first end and a second end coupled to the working voltage; a current sink unit having a first end and a second end coupled to the working voltage; a second terminal of the ground terminal; a first switch having a first electrical terminal coupled to the first terminal of the current source unit, a second electrical terminal, and a control coupled to a first control signal terminal; a second switch having a first electrical terminal coupled to the first terminal of the current tank unit, a second electrical terminal, and a control terminal coupled to a second control signal, and the first electrical terminal The second electrical terminal of a switch and the second electrical terminal of the second switch are coupled to a common contact; and a resistor, a first end of which is coupled to the common contact, and a second The terminal is coupled to the ground terminal.

In a possible embodiment, in the voltage maintaining time interval, the second switch is turned on according to the control of the second control signal and the first switch is turned off according to the control of the first control signal, so that the current source is The unit provides a first current flowing through the resistor, so that the first end of the resistor has a resistor terminal voltage as the adjustment voltage.

In another possible embodiment, in the voltage maintaining time interval, the first switch is turned on according to the control of the first control signal and the second switch is turned off according to the control of the second control signal, so that the current The tank unit provides a second current flowing through the resistor, so that the first end of the resistor has a resistor terminal voltage as the adjustment voltage.

The present invention also provides an OLED display, which includes at least one display driver chip and an OLED display panel, wherein the OLED display panel includes the first embodiment of the OLED pixel compensation circuit of the present invention as described above.

In addition, the present invention further provides an information processing device, which has an OLED display, and the OLED display includes the first embodiment of the OLED pixel compensation circuit of the present invention as described above.

The present invention also provides another OLED display, which includes at least one display driver chip and an OLED display panel, wherein the OLED display panel includes the second embodiment of the OLED pixel compensation circuit of the present invention as described above.

In addition, the present invention provides another information processing device, which has an OLED display, and the OLED display includes the second embodiment of the OLED pixel compensation circuit of the present invention as described above.

In a feasible embodiment, the aforementioned information processing device is an electronic device selected from the group consisting of smart phones, smart watches, smart bracelets, tablet computers, notebook computers, all-in-one computers, and access control devices device.

1a: OLED display

11a: OLED display panel

111a: OLED sub-pixel

112a: Pixel Circuits

1121a: drive current generation unit

1122a: Voltage maintenance capacitor

11Sa: source drive line

11Ga: gate drive line

12a: Gate drive circuit

13a: Source driver circuit

14a: Display Controller

1: OLED display

11: OLED display panel

111: OLED sub-pixel

112: Pixel circuit

1121: drive current generation unit

1122: Voltage maintenance capacitor

1123: Mode switch

11S: source drive line

11G: Gate drive line

12: Gate drive circuit

13: Source driver circuit

14: Display Controller

20: Signal transmission line

21: Voltage adjustment unit

211: Current source unit

212: Current sink unit

213: The first switch

214: Second switch

215: Common contact

216: Resistor

1 is a block diagram of a conventional OLED display; FIG. 2 is a block diagram of N pixel circuits in the i-th row of the OLED display panel of FIG. 1 ; FIGS. 3 a , 3 b and 3 c are conventional pixel circuits Schematic diagram of circuit operation of the circuit; FIG. 4 is a graph of the voltage maintaining time of a conventional voltage maintaining capacitor and the amount of voltage change of the capacitor; FIG. 5 is a block diagram of an OLED display integrated with an OLED pixel compensation circuit of the present invention; 6a is a block diagram showing M pixel circuits in the jth column of the OLED display panel of FIG. 5; FIG. 6b is a block diagram showing M pixel circuits in the jth column of the OLED display panel of FIG. 5; FIG. 6c It is a block diagram showing M pixel circuits in the jth row of the OLED display panel of FIG. 5; FIG. 7 is the voltage maintaining time of the voltage maintaining capacitor and the variation of the capacitor voltage and the adjustment voltage of the OLED pixel compensation circuit of the present invention. Graph; Fig. 8 is a block diagram of an OLED display integrated with an OLED pixel compensation circuit of the present invention; Fig. 9a is a block diagram of N pixel circuits in the i-th row of the OLED display panel of Fig. 8; Fig. 9b FIG. 8 is a block diagram of N pixel circuits in the i-th row of the OLED display panel of FIG. 8 ; and FIG. 9c is a block diagram of N pixel circuits in the i-th row of the OLED display panel of FIG. 8 .

In order to enable your examiners to further understand the structure, features, objectives, and advantages of the present invention, drawings and detailed descriptions of preferred embodiments are attached as follows.

first embodiment

The present invention mainly discloses an OLED pixel compensation circuit, which is applied in an OLED display panel to generate an adjustment voltage, so as to use the adjustment voltage to adjust a driving voltage transmitted to a plurality of pixel circuits, so that the A driving current generating unit of the selected at least one pixel circuit can generate a driving current according to the driving voltage without being affected by the I _OFF current and/or the leakage current of the voltage maintaining capacitor 2 . In other words, by changing the way of adjusting the voltage, the I _OFF current of the pixel circuit and the leakage current of the voltage maintaining capacitor can be removed, so as to ensure that the OLED display panel will not appear flicker during the process of displaying the image. Phenomenon.

FIG. 5 shows a block diagram of an OLED display integrated with an OLED pixel compensation circuit of the present invention. As shown in FIG. 5 , the OLED display 1 mainly includes: an OLED display panel 11 , a gate (column) driving circuit 12 , a source (row) driving circuit 13 , and a display controller 14 . The OLED display panel 11 includes N×M OLED sub-pixels 111 , N×M pixel circuits 112 , M source driving lines 11S, and N gate driving lines 11G. Moreover, each gate driving line 11G is coupled to M pixel circuits 112 along the column direction, and each source driving line 11S is coupled to N pixel circuits 112 along the row direction.

6a , 6b and 6c all show block diagrams of M pixel circuits in the jth column of the OLED display panel of FIG. 5 . As shown in FIG. 5 , each of the OLED sub-pixels 111 is coupled to one of the pixel circuits 112 , wherein the pixel circuit 112 includes: a driving current generating unit 1121 , a voltage maintaining capacitor 1122 , and a mode switching switch 1123. In the first embodiment, the OLED pixel compensation circuit of the present invention includes N signal transmission lines 20 and N voltage adjustment units 21 . As shown in FIG. 6 a , each of the signal transmission lines 20 is coupled to a second end of the M voltage maintaining capacitors 1122 in the same row, and the N voltage adjustment units 21 are respectively coupled to the N signal transmission lines 20 . . Wherein, each of the voltage adjustment units 21 has a first electrical terminal, a second electrical terminal and a third electrical terminal, the first electrical terminal is coupled to the signal transmission line 20, the second electrical terminal The terminal is coupled to a ground terminal GND, and the third electrical terminal is coupled to a working voltage V _DD .

In more detail, each of the voltage adjustment units 21 includes: a current source unit 211 , a current sink unit 212 , a first switch 213 , a second switch 214 , and a resistor 216 . It can be seen from FIG. 6a that the current source unit 211 has a first terminal and a second terminal coupled to the working voltage V _DD , and the current sink unit 212 has a first terminal and a first terminal coupled to the ground terminal GND. two ends. On the other hand, the first switch 213 has a first electrical terminal coupled to the first terminal of the current source unit 211 , a second electrical terminal, and a control terminal coupled to a first control signal S1 , and the second switch 214 has a first electrical terminal coupled to the first terminal of the current tank unit 212, a second electrical terminal, and a control terminal coupled to a second control signal S2, and The second electrical terminal of the first switch 213 and the second electrical terminal of the second switch 214 are coupled to a common contact 215 . Moreover, a first end of the resistor 216 is coupled to the common contact 215, and a second end of the resistor 216 is coupled to the ground terminal GND.

According to this design, in a capacitor charging time interval, the pixel circuit 112 receives a display data signal V _DATA through the source driving line 11S, and the voltage adjusting unit 21 provides a ground voltage through the signal transmission line 20 to The second end of the voltage maintaining capacitor 1122 enables the voltage maintaining capacitor to be charged to have a capacitance value Cs after receiving the display data signal V _DATA . At this time, the first terminal of the voltage maintaining capacitor has a capacitor terminal voltage V1=Cs.

It should be known that the driving current generating unit 1121 is composed of a plurality of thin film transistor (TFT) elements, and the process error often causes the threshold voltage values of the plurality of thin film transistor elements to be inconsistent. At the same time, the variation or drift of the threshold voltage caused by the process error will also cause the different two driving current generating units 1121 to have different I _OFF currents, and also cause the different two voltage maintaining capacitors 1122 to have different capacitance leakages. Therefore, as shown in FIG. 6b, in a voltage maintaining time interval, the terminal voltage of the voltage maintaining capacitor 1122 will be maintained at V1 originally, but an I _OFF current of the driving current generating unit 1121 causes the terminal voltage of the voltage maintaining capacitor 1122 to be maintained. It becomes V1+△V. Among them, △V=(I _OFF *T)/Cs. Therefore, according to the design of the present invention, in the voltage maintenance time interval, the voltage adjustment unit 21 provides an adjustment voltage _VB to the second end of the voltage maintenance capacitor 1122 through the signal transmission line 20, so as to utilize The adjustment voltage V _B adjusts the capacitor terminal voltage of the voltage maintaining capacitor 1122 to a driving voltage V _G .

In more detail, if the pixel circuit 112 only has the leakage current of the voltage maintaining capacitor 1122 itself, the OLED pixel compensation circuit of the present invention will make the second switch 214 control the second switch 214 within the voltage maintaining time interval. The control of the signal S2 is turned on (ie, a closed circuit is formed internally) and the first switch 213 is turned off according to the control of the first control signal S1 (ie, an open circuit is formed internally), so that the current sink unit 212 A first current I1 is provided to flow through the resistor 216 , so that the first end of the resistor 216 has a resistor terminal voltage -ΔV as the adjustment voltage V _B . In this case, a driving voltage V _G transmitted to the driving current generating unit 1121 is V _G =V1+ΔV+ _VB , and the driving current generating unit 1121 generates a driving current according to the driving voltage V _G so as to The OLED sub-pixel 111 is driven to emit light. For example, V1 is 5V, a voltage maintaining time T elapsed by the voltage maintaining capacitor 1122 in the voltage maintaining time interval is, the capacitor voltage variation ΔV caused by the leakage current of the capacitor is 0.5V, and the resistance 216 is 0.1 MΩ. At this time, as long as the first current I1 provided by the current source unit 211 and flowing through the resistor 216 is 5 μA, the driving voltage V _G is 5V+0.5V−0.5V=5V. It can be seen from this that the OLED pixel compensation circuit of the present invention can remove the bad influence on the driving voltage V _G caused by the leakage of the voltage maintaining capacitor 1122 , thereby maintaining the stability of the driving voltage V _G .

On the other hand, as shown in FIG. 6c, if the pixel circuit 112 only has the I _OFF current of the driving current generating unit 1121, the OLED pixel compensation circuit of the present invention will make the first The switch 213 is turned on according to the control of the first control signal S1 and the second switch 214 is turned off according to the control of the second control signal S2 , so that the current source unit 211 provides a second current flowing through the resistor 216 I2, so that the first terminal of the resistor 216 has a resistor terminal voltage +ΔV as the adjustment voltage V _B . In this case, a driving voltage V _G transmitted to the driving current generating unit 1121 is V _G =V1-ΔV+ _VB , and the driving current generating unit 1121 generates a driving current according to the driving voltage V _G Thus, the OLED sub-pixel 111 is driven to emit light. For example, V1 is 5V, the capacitance voltage change ΔV due to the I _OFF current is -0.5V, and the resistor 216 is 0.1MΩ. At this time, as long as the second current I2 provided by the current tank unit 212 and flowing through the resistor 216 is 5 μA, the driving voltage V _G is 5V−0.5V+0.5V=5V. It can be seen that the OLED pixel compensation circuit of the present invention can remove the adverse effect of the I _OFF current of the dynamic current generating unit 1121 of the pixel circuit 112 on the driving voltage V _G , thereby maintaining the stability of the driving voltage V _G.

T)，如此才可以完全、有效地去除電壓維持電容1122的漏電對驅動電壓V_G所造成的不良影響，從而維持驅動電壓V_G的穩定。 FIG. 7 is a graph showing the voltage maintaining time of the voltage maintaining capacitor 1122 , the capacitance voltage variation ΔV, and the adjustment voltage _VB . As shown in FIGS. 6a , 6b and 7 , the voltage adjustment unit 21 determines whether the adjustment voltage _VB provided to the second end of the voltage maintaining capacitor 1122 is a positive voltage or a negative voltage according to the direction of the leakage current. For example, the voltage maintaining capacitor 1122 has a leakage current, and the leakage current causes the capacitor voltage Cs to drop by ΔV (ie, the capacitor voltage variation). At this time, the voltage adjustment unit 21 of the OLED pixel compensation circuit of the present invention provides a positive adjustment voltage _VB to the second terminal of the voltage maintaining capacitor 1122, so that the capacitor terminal voltage of the second terminal is V1-ΔV+V _B. It is worth noting that since the capacitance voltage variation is caused by the leakage of the voltage maintaining capacitor 1122 itself, as shown in FIG. 7 , the adjustment voltage _VB must be proportional to the elapsed voltage maintaining time (V _B

T), in this way, the adverse effect of the leakage of the voltage maintaining capacitor 1122 on the driving voltage V _G can be completely and effectively removed, thereby maintaining the stability of the driving voltage V _G.

Second Embodiment

FIG. 8 shows a block diagram of an OLED display integrated with an OLED pixel compensation circuit of the present invention. 9a, 9b and 9c all show block diagrams of N pixel circuits in the i-th row of the OLED display panel of FIG. 8 . As shown in FIG. 8 and FIG. 9 a , in the second embodiment, the OLED pixel compensation circuit of the present invention includes N×M voltage adjustment units 21 . The voltage adjustment unit 21 has a first electrical terminal, a second electrical terminal and a third electrical terminal, and the first electrical terminal is coupled to a second terminal of the voltage maintaining capacitor 1122 , The second electrical terminal is coupled to a ground terminal GND, and the third electrical terminal is coupled to a working voltage V _DD .

In more detail, each of the voltage adjustment units 21 includes: a current source unit 211 , a current sink unit 212 , a first switch 213 , a second switch 214 , and a resistor 216 . It can be seen from FIG. 9a that the current source unit 211 has a first terminal and a second terminal coupled to the working voltage V _DD , and the current sink unit 212 has a first terminal and a first terminal coupled to the ground terminal GND. two ends. On the other hand, the first switch 213 has a first electrical terminal coupled to the first terminal of the current source unit 211 , a second electrical terminal, and a control terminal coupled to a first control signal S1 , and the second switch 214 has a first electrical terminal coupled to the first terminal of the current tank unit 212, a second electrical terminal, and a control terminal coupled to a second control signal S2, and The second electrical terminal of the first switch 213 and the second electrical terminal of the second switch 214 are coupled to a common contact 215 . Moreover, a first end of the resistor 216 is coupled to the common contact 215, and a second end of the resistor 216 is coupled to the ground terminal GND.

According to this design, in a capacitor charging time interval, the pixel circuit 112 receives a display data signal V _DATA through the source driving line 11S, and the voltage adjusting unit 21 provides a ground voltage through the signal transmission line 20 to The second end of the voltage maintaining capacitor 1122 enables the voltage maintaining capacitor to be charged to have a capacitance value Cs after receiving the display data signal V _DATA . At this time, the first terminal of the voltage maintaining capacitor has a capacitor terminal voltage V1=Cs.

In more detail, as shown in FIG. 9b, if the pixel circuit 112 only has the leakage current of the voltage maintaining capacitor 1122 itself, the OLED pixel compensation circuit of the present invention will make the second switch within the voltage maintaining time interval. 214 is turned on according to the control of the second control signal S2 and the first switch 213 is turned off according to the control of the first control signal S1, so that the current source unit 212 provides a first current I1 flowing through the resistor 216. A current I1 causes the first terminal of the resistor 216 to have a resistor terminal voltage as the adjustment voltage V _B . In this case, a driving voltage V _G transmitted to the driving current generating unit 1121 is V _G =V1-ΔV+V _B . Therefore, as long as V _B =ΔV, the adverse effect of removing the leakage of the voltage maintaining capacitor 1122 on the driving voltage V _G can be eliminated, thereby maintaining the stability of the driving voltage V _G.

On the other hand, as shown in FIG. 9c, if the pixel circuit 112 only has the I _OFF current of the driving current generating unit 1121, the OLED pixel compensation circuit of the present invention will make the first The switch 213 is turned on according to the control of the first control signal S1 and the second switch 214 is turned off according to the control of the second control signal S2 , so that the current sink unit 212 provides a second current I2 flowing through the resistor 216 , so that the first terminal of the resistor 216 has a resistor terminal voltage as the adjustment voltage V _B . In this case, a driving voltage V _G transmitted to the driving current generating unit 1121 is V _G =V1+ _ΔVVB . It should be understood that as long as V _B =ΔV, the adverse effect of removing the leakage of the voltage maintaining capacitor 1122 on the driving voltage V _G can be eliminated, thereby maintaining the stability of the driving voltage V _G.

In this way, the above has completely and clearly explained the OLED pixel compensation circuit of the present invention; and, through the above, it can be known that the present invention has the following advantages:

(1) The present invention discloses an OLED pixel compensation circuit, which is applied in an OLED display panel and includes N signal transmission lines and N voltage adjustment units. During a capacitor charging time interval, the voltage adjustment unit provides a grounding voltage to the second end of a voltage maintaining capacitor of a pixel circuit through the signal transmission line, so that the voltage maintaining capacitor is maintained at a voltage level through a display data signal. After charging, its first terminal has a capacitor terminal voltage. And, in a voltage maintenance time interval, the voltage adjustment unit provides an adjustment voltage to the second end of the voltage maintenance capacitor through the signal transmission line, so as to use the adjustment voltage to maintain the voltage at the capacitor end of the capacitor The voltage is adjusted to a driving voltage. By changing the way of adjusting the voltage, the leakage current of the pixel circuit and the voltage maintaining capacitor can be removed, so as to ensure that the OLED display panel will not cause the phenomenon of picture flicker during the process of displaying the image picture.

(2) The present invention also provides an OLED display, which includes at least one display driver chip and an OLED display panel, and the OLED display panel includes the OLED pixel compensation circuit of the present invention as described above.

(3) The present invention also provides an information processing device having an OLED display including at least one display driver chip and an OLED display panel, and the OLED display panel includes the OLED pixel compensation circuit of the present invention as described above. Moreover, the aforementioned information processing device is an electronic device selected from the group consisting of smart phones, smart watches, smart bracelets, tablet computers, notebook computers, all-in-one computers, and access control devices.

It must be emphasized that the above-mentioned disclosure in this case is a preferred embodiment, and any partial changes or modifications originating from the technical ideas of this case and easily inferred by those who are familiar with the art are within the scope of the patent of this case. category of rights.

To sum up, regardless of the purpose, means and effect of this case, it shows that it is completely different from the conventional technology, and its first invention is suitable for practical use, and indeed meets the patent requirements of the invention. Society is to pray for the best.

111: OLED sub-pixel

112: Pixel circuit

1121: drive current generation unit

1122: Voltage maintenance capacitor

1123: Mode switch

11S: source drive line

20: Signal transmission line

21: Voltage adjustment unit

211: Current source unit

212: Current sink unit

213: The first switch

214: Second switch

215: Common contact

216: Resistor

Claims (9)

An OLED pixel compensation circuit is applied in an OLED display including at least one display driver chip and an OLED display panel; wherein, the OLED display panel includes N×M OLED sub-pixels and N×M pixels circuit, and each pixel circuit includes a driving current generating unit and a voltage maintaining capacitor coupled to the driving current generating unit with a first end thereof; the OLED pixel compensation circuit includes: N signal transmission lines, wherein , each of the signal transmission lines is coupled with a second end of the M voltage maintenance capacitors in the same row; and N voltage adjustment units, wherein each of the voltage adjustment units has a first electrical terminal, a first electrical terminal Two electrical terminals and a third electrical terminal, the first electrical terminal is coupled to a signal transmission line, the second electrical terminal is coupled to a ground terminal, and the third electrical terminal is coupled to a working voltage ; wherein, in a capacitor charging time interval, the voltage adjustment unit provides a ground voltage to the second end of the voltage maintenance capacitor through the signal transmission line, so that the voltage maintenance capacitor is charged by a display data signal Then, the first terminal has a capacitor terminal voltage; and wherein, each of the voltage adjustment units includes: a current source unit with a first terminal and a second terminal coupled to the working voltage; a current sink The unit has a first terminal and a second terminal coupled to the ground terminal; a first switch has a first electrical terminal coupled to the first terminal of the current source unit, a second electrical terminal, and a control terminal coupled to a first control signal; a second switch having a first electrical terminal coupled to the first terminal of the current sink unit, a second electrical terminal, and a first electrical terminal coupled to A control terminal of two control signals, and the second electrical terminal of the first switch and the second electrical terminal of the second switch are coupled to a common contact; and a resistor, a first terminal of which is coupled to the common point, and a second end thereof is coupled to the ground end. The OLED pixel compensation circuit of claim 1, wherein, in a voltage maintaining time interval, the voltage adjusting unit provides an adjustment voltage to the second end of the voltage maintaining capacitor through the signal transmission line, thereby The capacitor terminal voltage of the voltage maintaining capacitor is adjusted to a driving voltage by using the adjustment voltage. The OLED pixel compensation circuit of claim 1, wherein, in the voltage maintaining time interval, the second switch is turned on according to the control of the second control signal, and the first switch is turned on according to the control of the first control signal The current source unit is controlled to be turned off, so that the current source unit provides a first current flowing through the resistor, so that the first end of the resistor has a resistor terminal voltage as the adjustment voltage. The OLED pixel compensation circuit of claim 1, wherein, in the voltage maintaining time interval, the first switch is turned on according to the control of the first control signal, and the second switch is turned on according to the control of the second control signal It is controlled to be turned off, so that the current sink unit provides a second current flowing through the resistor, so that the first end of the resistor has a resistor terminal voltage as the adjustment voltage. An OLED pixel compensation circuit is applied in an OLED display including at least one display driver chip and an OLED display panel 11; wherein, the OLED display panel includes N×M OLED sub-pixels and N×M picture elements pixel circuit, and each pixel circuit includes a driving current generating unit and a voltage maintaining capacitor coupled to the driving current generating unit with a first end thereof; the OLED pixel compensation circuit includes: N×M voltages an adjustment unit, wherein each of the voltage adjustment units has a first electrical terminal, a second electrical terminal and a third electrical terminal, and the first electrical terminal is coupled to a second terminal of the voltage maintaining capacitor , the second electrical terminal is coupled to a ground terminal, and the third electrical terminal is coupled to a working voltage; wherein, in a capacitor charging time interval, the voltage adjustment unit provides a ground voltage to maintain the voltage The second end of the capacitor enables the first end of the voltage maintaining capacitor to have a capacitor terminal voltage after being charged by a display data signal; and wherein each of the voltage adjustment units includes: a current source unit, has a first end and a second end coupled to the working voltage; a current sink unit has a first end and a second end coupled to the ground end; a first switch has a current source unit coupled to a first electrical terminal of the first terminal, a second electrical terminal, and a control terminal coupled to a first control signal; a second switch has the first terminal coupled to the current tank unit a first electrical terminal, a second electrical terminal, and a control terminal coupled to a second control signal; wherein, the second electrical terminal of the first switch and the second electrical terminal of the second switch The electrical terminal is coupled to a common point; and a resistor has a first terminal coupled to the common terminal and a second terminal coupled to the ground terminal. The OLED pixel compensation circuit of claim 5, wherein, within a voltage maintenance time interval, the voltage adjustment unit provides an adjustment voltage to the second end of the voltage maintenance capacitor, so that the adjustment voltage is used to The capacitor terminal voltage of the voltage maintaining capacitor is adjusted to a driving voltage. The OLED pixel compensation circuit according to claim 5, wherein, in the voltage maintaining time interval, the second switch is turned on according to the control of the second control signal, and the first switch is turned on according to the control of the first control signal It is controlled to be turned off, so that the current source unit provides a first current flowing through the resistor, so that the first end of the resistor has a resistor terminal voltage as the adjustment voltage. The OLED pixel compensation circuit of claim 5, wherein in the voltage maintaining time interval, the first switch is turned on according to the control of the first control signal, and the second switch is turned on according to the control of the second control signal It is controlled to be turned off, so that the current sink unit provides a second current flowing through the resistor, so that the first end of the resistor has a resistor terminal voltage as the adjustment voltage. An information processing device has an OLED display, wherein the OLED display includes the OLED pixel compensation circuit according to any one of claim 1 to claim 8.

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