CN109767725A

CN109767725A - A kind of pixel-driving circuit and its driving method, display device

Info

Publication number: CN109767725A
Application number: CN201910207648.9A
Authority: CN
Inventors: 卢俊宏; 徐波; 沈灿; 古涛; 高超; 曹江; 李海燕
Original assignee: BOE Technology Group Co Ltd; Chongqing BOE Optoelectronics Technology Co Ltd
Current assignee: BOE Technology Group Co Ltd; Chongqing BOE Optoelectronics Technology Co Ltd
Priority date: 2019-03-19
Filing date: 2019-03-19
Publication date: 2019-05-17

Abstract

The present invention discloses a kind of pixel-driving circuit and its driving method, display device, it is related to field of display technology, to solve the light-emitting component aging due to including in display device, so that the light emission luminance of light-emitting component reduces, it is uneven so as to cause the display brightness of display device, the problem of influencing the display effect of display device.The pixel-driving circuit includes: the transparent light-sensitive element with light-emitting component stacking setting；The drive sub-circuits being connected to the light emitting element；The control sub-circuit being connect respectively with drive sub-circuits and transparent light-sensitive element, for according to the feedback signal fed back by transparent light-sensitive element, it treats and inputs to the original data signals of drive sub-circuits and be adjusted, and target data signal adjusted is exported to drive sub-circuits；Drive sub-circuits are used to drive light-emitting component to shine according to target data signal.Pixel-driving circuit provided by the invention is for driving light-emitting component to shine.

Description

Pixel driving circuit, driving method thereof and display device

Technical Field

The invention relates to the technical field of display, in particular to a pixel driving circuit, a driving method thereof and a display device.

Background

The Organic Light-Emitting Diode (OLED) display technology is different from the conventional liquid crystal display technology, and an OLED display device manufactured by the OLED display technology does not need liquid crystal molecules and a backlight source, and has the advantages of high contrast, wide color gamut, and the like. However, as the OLED display device is used for a long time, the organic light emitting material in the light emitting element included therein is easily aged, so that the light emitting luminance of the light emitting element is reduced, thereby causing the display luminance of the display device to be uneven, and affecting the display effect of the display device.

Disclosure of Invention

The invention aims to provide a pixel driving circuit, a driving method thereof and a display device, which are used for solving the problems that the display effect of the display device is influenced due to the uneven display brightness of the display device caused by the reduction of the luminance of a light-emitting element due to the aging of the light-emitting element included in the display device.

In order to achieve the above purpose, the invention provides the following technical scheme:

a first aspect of the present invention provides a pixel driving circuit for driving a light emitting element to emit light, comprising:

a transparent photosensor disposed in a stacked manner with the light emitting element, the resistance value of the transparent photosensor being variable with a change in luminance of the light emitting element;

a driving sub-circuit connected to the light emitting element;

the control sub-circuit is respectively connected with the driving sub-circuit and the transparent photosensitive element and is used for adjusting an original data signal to be input to the driving sub-circuit according to a feedback signal fed back by the transparent photosensitive element and outputting an adjusted target data signal to the driving sub-circuit;

the driving sub-circuit is used for driving the light-emitting element to emit light according to the target data signal.

Optionally, the control sub-circuit includes: the first control unit and the second control unit are connected; wherein,

the first control unit is respectively connected with the driving sub-circuit and the transparent photosensitive element and used for comparing the received feedback signal with a preset reference signal to determine a difference signal, and when the difference signal is not equal to 0, the difference signal is transmitted to the second control unit;

the second control unit is used for determining a compensation data signal according to the difference signal and transmitting the compensation data signal back to the first control unit;

the first control unit is further configured to obtain the target data signal according to the original data signal and the compensation data signal, and output the target data signal to the driving sub-circuit.

Optionally, the second control unit further includes a storage subunit, and the storage subunit is configured to store a corresponding relationship between the difference signal and the compensation data signal.

Optionally, the transparent photosensitive element includes a transparent photosensitive adhesive pattern, and the transparent photosensitive adhesive pattern is doped with a photoresistance material.

Optionally, the light emitting element includes a first electrode and a second electrode disposed opposite to each other, and a light emitting layer disposed between the first electrode and the second electrode, and an orthographic projection of the transparent photosensor on the light emitting element coincides with the light emitting layer.

Optionally, the driving sub-circuit includes:

a drive unit for driving the motor to rotate,

the first end of the storage unit is connected with the control end of the driving unit, and the second end of the storage unit is connected with the power supply signal input end;

the power supply control unit is respectively connected with a power supply control end, the power supply signal input end and the input end of the driving unit and is used for controlling connection or disconnection between the power supply signal input end and the input end of the driving unit under the control of the power supply control end;

the signal input unit is respectively connected with an input control end, the control sub-circuit and the input end of the driving unit and is used for controlling connection or disconnection between the control sub-circuit and the input end of the driving unit under the control of the input control end;

the compensation unit is respectively connected with a compensation control end, a control end of the driving unit and an output end of the driving unit and is used for controlling connection or disconnection between the control end of the driving unit and the output end of the driving unit under the control of the compensation control end;

the first reset unit is respectively connected with the first reset control end, the control end of the driving unit and the reference signal input end and is used for controlling connection or disconnection between the control end of the driving unit and the reference signal input end under the control of the first reset control end;

the light-emitting control unit is respectively connected with a light-emitting control end, the output end of the driving unit and the first end of the light-emitting element and is used for controlling the connection between the output end of the driving unit and the first end of the light-emitting element to be switched on or off under the control of the light-emitting control end;

and the second reset unit is respectively connected with a second reset control end, the reference signal input end and the first end of the light-emitting element and is used for controlling the connection between the reference signal input end and the first end of the light-emitting element to be switched on or switched off under the control of the second reset control end.

Optionally, the driving unit includes a driving transistor;

the storage unit comprises a storage capacitor, a first end of the storage capacitor is connected with the grid electrode of the driving transistor, and a second end of the storage capacitor is connected with the power supply signal input end;

the power supply control unit comprises a first transistor, the grid electrode of the first transistor is connected with the power supply control end, the first pole of the first transistor is connected with the power supply signal input end, and the second pole of the first transistor is connected with the first pole of the driving transistor;

the signal input unit comprises a second transistor, the grid electrode of the second transistor is connected with the input control end, the first pole of the second transistor is connected with the control sub-circuit, and the second pole of the second transistor is connected with the first pole of the driving transistor;

the compensation unit comprises a third transistor, wherein the grid electrode of the third transistor is connected with the compensation control end, the first pole of the third transistor is connected with the second pole of the driving transistor, the first pole of the third transistor is connected with the grid electrode of the driving transistor, and the second pole of the third transistor is connected with the second pole of the driving transistor;

the first reset unit comprises a fourth transistor, a grid electrode of the fourth transistor is connected with the first reset control end, a first pole of the fourth transistor is connected with the reference signal input end, and a second pole of the fourth transistor is connected with the grid electrode of the driving transistor;

the light-emitting control unit comprises a fifth transistor, wherein the grid electrode of the fifth transistor is connected with the light-emitting control end, the first pole of the fifth transistor is connected with the second pole of the driving transistor, and the second pole of the fifth transistor is connected with the first end of the light-emitting element;

the second reset unit includes a sixth transistor, a gate of the sixth transistor is connected to the second reset control terminal, a first pole of the sixth transistor is connected to the reference signal input terminal, and a second pole of the sixth transistor is connected to the first end of the light emitting element.

Based on the technical solution of the pixel driving circuit, a second aspect of the present invention provides a display device, which includes a source driving chip, a central control chip, and a plurality of pixel driving circuits, wherein the transparent photosensitive elements and the driving sub-circuits included in the plurality of pixel driving circuits are distributed in an array;

the source electrode driving chip comprises a plurality of first control units, the driving sub-circuits positioned in the same column multiplex one first control unit, and the driving sub-circuits positioned in the same column are connected with the corresponding first control units through the same data signal transmission line; one end of the transparent photosensitive elements positioned in the same column is connected with the corresponding first control unit through the same first feedback signal transmission line, and the other end of the transparent photosensitive elements positioned in the same column is connected with the corresponding first control unit through the same second feedback signal transmission line;

the central control chip comprises a second control unit, and the plurality of first control units multiplex the second control unit.

Based on the technical solution of the pixel driving circuit, a third aspect of the present invention provides a driving method of a pixel driving circuit, which is applied to the pixel driving circuit, and the driving method includes:

a transparent photosensitive element in the pixel driving circuit senses the change of the luminance of the light-emitting element and feeds back a feedback signal to the control sub-circuit;

the control sub-circuit adjusts an original data signal to be input to the driving sub-circuit according to the feedback signal and outputs an adjusted target data signal to the driving sub-circuit;

the driving sub-circuit drives the light-emitting element to emit light according to the target data signal.

Optionally, when the control sub-circuit includes: when the first control unit and the second control unit are connected, the step of adjusting the original data signal to be input to the driving sub-circuit by the control sub-circuit according to the feedback signal and outputting the adjusted target data signal to the driving sub-circuit specifically comprises:

the first control unit compares the feedback signal with a preset reference signal, determines a difference signal, and transmits the difference signal to the second control unit when the difference signal is not equal to 0;

the second control unit determines a compensation data signal according to the difference signal and transmits the compensation data signal back to the first control unit;

the first control unit obtains the target data signal according to the original data signal and the compensation data signal, and outputs the target data signal to the driving sub-circuit.

In the technical scheme provided by the invention, the pixel driving circuit comprises a transparent photosensitive element, a driving sub-circuit and a control sub-circuit, the transparent photosensitive element and the light-emitting element are arranged in a stacked manner, the transparent photosensitive element can sense the change of the light-emitting brightness of the light-emitting element and transmit a corresponding feedback signal to the control sub-circuit, the control sub-circuit can compensate an original data signal according to the feedback signal to obtain a target data signal and transmit the target data signal to the driving sub-circuit, and the driving sub-circuit drives the light-emitting element to emit light according to the target data signal so as to compensate the light-emitting brightness of the light-emitting element, so that the aged light-emitting element can also emit light with normal brightness. Therefore, in the technical scheme provided by the invention, the detection and compensation of the luminous efficiency of the luminous element are realized through the transparent photosensitive element and the control sub-circuit, so that the luminous efficiency is reduced, and the luminous element with reduced luminous brightness can also emit light rays meeting the preset required brightness, so that when the pixel driving circuit is applied to a display device, the display brightness of the display device can be uniform, and the display effect of the display device is well ensured.

In addition, in the technical scheme provided by the invention, the transparent photosensitive element and the light-emitting element are arranged in a laminated manner, so that the transparent photosensitive element does not occupy the space around the light-emitting element, and when the pixel driving circuit is applied to a display device, the arranged transparent photosensitive element does not influence the pixel aperture ratio of the display device, the pixel aperture ratio of the display device can be maximized, and the display device has higher brightness under the same driving signal, thereby achieving the effect of low power consumption. Further, since the aperture ratio is maximized, a lower current is required in achieving a target luminance as compared with other display devices, and the reduction of the current is advantageous in extending the life of the light emitting element, thereby extending the life of the light emitting element.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic diagram of a first structure of a pixel driving circuit according to an embodiment of the invention;

fig. 2 is a schematic diagram of a second structure of a pixel driving circuit according to an embodiment of the invention;

fig. 3 is a schematic diagram of a third structure of a pixel driving circuit according to an embodiment of the invention;

FIG. 4 is a schematic cross-sectional view of a transparent photosensitive element and a light emitting element provided by an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a display device according to an embodiment of the present invention.

Reference numerals:

1-a drive sub-circuit, 10-a drive unit,

11-a storage unit, 12-a power control unit,

13-a signal input unit, 14-a compensation unit,

15-a first reset unit, 16-a light emission control unit,

17-a second reset unit, 2-a control sub-circuit,

20-a first control unit, 21-a second control unit,

3-a central control chip, 4-a source driving chip,

5-a data signal transmission line, 6-a first feedback signal transmission line,

7-a light-emitting element, 8-a substrate,

DTFT-drive transistor, Cst-storage capacitor,

t1-first transistor, T2-second transistor,

t3-third transistor, T4-fourth transistor,

t5-fifth transistor, T6-sixth transistor,

a DM-power supply control terminal, a VDD-power supply signal input terminal,

gate 1-input control terminal, Gate 2-compensation control terminal,

reset (n) -a first reset control terminal, Init-reference signal input terminal,

EM-emission control terminal, Reset (N +1) -second Reset control terminal,

RL-transparent photosensitive element.

Detailed Description

In order to further explain the pixel driving circuit, the driving method thereof and the display device provided by the embodiment of the invention, the following detailed description is made with reference to the accompanying drawings.

In the related art, the light emitting elements in the OLED display device are generally made of organic light emitting materials, and the organic light emitting materials are prone to aging due to factors such as too long use time or invasion of water and oxygen, and when currents of the same magnitude flow through the same light emitting elements before and after aging, the luminance of the light emitting elements is different, so that the display luminance of the display device is uneven, and the display effect of the display device is affected.

Based on the above problems, the inventor of the present invention has found that when the same light emitting element before and after aging flows the same current, the light emitting brightness of the light emitting element after aging is reduced, so that a device capable of sensing the light emitting brightness of the light emitting element is disposed around the light emitting element, and the light emitting brightness of the light emitting element is fed back by the device to determine whether the light emitting element is aged, and when the light emitting element is aged, a compensation signal can be input into the light emitting element to enable the aged light emitting element to emit the light with normal brightness, thereby ensuring the good display effect of the display device.

Specifically, referring to fig. 1 and fig. 4, an embodiment of the present invention provides a pixel driving circuit for driving a light emitting element 7 to emit light, the pixel driving circuit including: a transparent photosensitive element RL, a drive sub-circuit 1 and a control sub-circuit 2; the transparent photosensitive element RL and the light-emitting element 7 are arranged in a stacked mode, and the resistance value of the transparent photosensitive element RL can change along with the change of the luminance of the light-emitting element 7; the driving sub-circuit 1 is connected to the light emitting element 7; the control sub-circuit 2 is respectively connected with the driving sub-circuit 1 and the transparent photosensitive element RL, and is used for adjusting an original data signal to be input to the driving sub-circuit 1 according to a feedback signal fed back by the transparent photosensitive element RL and outputting an adjusted target data signal to the driving sub-circuit 1; the driving sub-circuit 1 is used for driving the light emitting element 7 to emit light according to a target data signal.

In more detail, the position of the transparent photosensitive element RL can be set according to actual needs, and only needs to be irradiated by the light emitted by the light emitting element 7, and exemplarily, the transparent photosensitive element RL can be arranged at the periphery of the light emitting element 7 or stacked with the light emitting element 7; when the light emitting element 7 emits light, the resistance value of the transparent photosensitive element RL can change along with the change of the light emitting brightness of the light emitting element 7, so that the current of a circuit where the transparent photosensitive element RL is located is changed, and the feedback function is realized. More specifically, after the light emitting element 7 ages, the light emitting efficiency is reduced, and the light emitting brightness is reduced, so that the resistance of the transparent photosensitive element RL is increased, and the current of the circuit in which the transparent photosensitive element RL is located is reduced.

The driving sub-circuit 1 is connected to the light emitting element 7, and configured to drive the light emitting element 7 to emit light according to the received data signal, specifically, output an original driving signal to the light emitting element 7 according to an original data signal, so as to drive the light emitting element 7 to emit light; a target driving signal may be output to the light emitting element 7 according to the target data signal to drive the light emitting element 7 to emit light.

The control sub-circuit 2 is respectively connected with the driving sub-circuit 1 and the transparent photosensitive element RL, on one hand, the control sub-circuit 2 can receive a feedback signal fed back by the transparent photosensitive element RL, and the feedback signal can be a current signal specifically; on the other hand, the control sub-circuit 2 can adjust the original data signal to be input to the driving sub-circuit 1 according to the feedback signal, and output the adjusted target data signal to the driving sub-circuit 1. It is noted that the original data signal refers to: when the light emitting element 7 is not aged, and the driving sub-circuit 1 drives the light emitting element 7 to emit light according to the original data signal, the light emitting element 7 can emit light with brightness meeting the preset requirement. The target data signal is: after the light emitting element 7 is aged, when the driving sub-circuit 1 drives the light emitting element 7 to emit light according to the target data signal, the light emitting element 7 can emit light with brightness meeting the preset requirement.

When the pixel driving circuit provided by the embodiment of the invention is actually applied, the control sub-circuit 2 outputs an original data signal to the driving sub-circuit 1; the driving sub-circuit 1 outputs an original driving signal to the light emitting element 7 according to the original data signal to drive the light emitting element 7 to emit light; the transparent photosensitive element RL senses the change of the luminance of the light-emitting element 7 and feeds back a feedback signal to the control sub-circuit 2; when the feedback signal shows that the light-emitting element 7 has attenuation, the control sub-circuit 2 adjusts the original data signal input to the driving sub-circuit 1 according to the feedback signal to obtain a target data signal, and outputs the target data signal to the driving sub-circuit 1; the driving sub-circuit 1 outputs a target driving signal to the light emitting element 7 according to the target data signal to drive the light emitting element 7 to emit light.

As can be seen from the specific structure and practical application manner of the pixel driving circuit, the pixel driving circuit according to the embodiment of the present invention includes the transparent photosensitive element RL, the driving sub-circuit 1, and the control sub-circuit 2, the transparent photosensitive element RL and the light emitting element 7 are stacked, the transparent photosensitive element RL can sense the change of the light emitting luminance of the light emitting element 7, and transmit the corresponding feedback signal to the control sub-circuit 2, the control sub-circuit 2 can compensate the original data signal according to the feedback signal to obtain the target data signal, and transmit the target data signal to the driving sub-circuit 1, and the driving sub-circuit 1 drives the light emitting element 7 to emit light according to the target data signal, so that the light emitting luminance of the light emitting element 7 is compensated, and the aged light emitting element 7 can also emit light with normal luminance. Therefore, in the pixel driving circuit provided by the embodiment of the invention, the detection and compensation of the luminous efficiency of the luminous element 7 are realized through the transparent photosensitive element RL and the control sub-circuit 2, so that the luminous efficiency is reduced, and the luminous element 7 with reduced luminous brightness can also emit light rays meeting the preset required brightness, so that when the pixel driving circuit is applied to a display device, the display brightness of the display device can be uniform, and the display effect of the display device is well ensured.

In addition, in the pixel driving circuit provided by the embodiment of the invention, the transparent photosensitive element RL and the light emitting element 7 are stacked, so that the transparent photosensitive element RL does not occupy the space around the light emitting element 7, and thus when the pixel driving circuit is applied to a display device, the provided transparent photosensitive element RL does not affect the pixel aperture ratio of the display device, and the pixel aperture ratio of the display device can be maximized, so that the display device has higher brightness under the same driving signal, and the effect of low power consumption is achieved. Further, since the aperture ratio is maximized, a lower current is required in achieving the target luminance than in other display devices, and the reduction of the current also contributes to the extension of the life of the light emitting element 7, thereby extending the use time of the light emitting element 7.

The specific structure of the control sub-circuit 2 provided in the foregoing embodiments is various, and as shown in fig. 2, in some embodiments, the control sub-circuit 2 provided in the foregoing embodiments includes: a first control unit 20 and a second control unit 21 connected; the first control unit 20 is connected to the driving sub-circuit 1 and the transparent photosensitive element RL, and configured to compare the received feedback signal with a preset reference signal, determine a difference signal, and transmit the difference signal to the second control unit 21 when the difference signal is not equal to 0; the second control unit 21 is configured to determine a compensation data signal according to the difference signal, and transmit the compensation data signal back to the first control unit 20; the first control unit 20 is further configured to obtain a target data signal according to the original data signal and the compensation data signal, and output the target data signal to the driving sub-circuit 1.

Specifically, the transparent photosensitive element RL is equivalent to a variable resistor, and the first control unit 20 may be connected to a first end and a second end of the transparent photosensitive element RL respectively, so as to connect the transparent photosensitive element RL to a circuit loop in the first control unit 20, thereby detecting a current signal of a circuit where the transparent photosensitive element RL is located, and obtaining a feedback signal fed back by the transparent photosensitive element RL.

After obtaining the feedback signal, the first control unit 20 may subtract the feedback signal from the preset reference signal to determine a difference signal, where when the feedback signal is the same as the preset reference signal, the difference signal is 0, when the feedback signal is different from the preset reference signal, the difference signal is not 0, and when the difference signal is not 0, the first control unit 20 transmits the difference signal to the second control unit 21, and the second control unit 21 determines the compensation data signal according to the difference signal and transmits the compensation data signal back to the first control unit 20.

It should be noted that the feedback signal may be selected as a feedback current signal, the preset reference signal may be selected as a reference current signal, and the difference signal is a difference between the feedback current signal and the reference current signal; the compensation data signal is a compensation voltage signal, the original data signal is an original voltage signal, the first control unit 20 can sum the original voltage signal and the compensation voltage signal after obtaining the compensation voltage signal to obtain a target data signal, i.e. a target voltage signal, and then the target data signal is transmitted to the driving sub-circuit 1, and the driving sub-circuit 1 drives the light-emitting element 7 to emit light according to the target data signal.

After the driving sub-circuit 1 drives the light-emitting element 7 to emit light according to the target data signal, the light-emitting brightness of the light-emitting element 7 is increased, and the target brightness meeting the requirement can be achieved, at this time, after the transparent photosensitive element RL senses the target brightness again, the feedback signal correspondingly fed back is the same as the preset reference signal, and the difference signal correspondingly obtained by the first control unit 20 is 0, so that the first control unit 20 does not need to transmit the difference signal to the second control unit 21.

In some embodiments, the second control unit 21 provided in the above embodiments further comprises a storage subunit, which is configured to store a correspondence between the difference signal and the compensation data signal.

Specifically, the correspondence between the difference signal and the compensation data signal can be obtained in various ways, for example, after the display panel is manufactured, a burn-in test and a Gamma test can be performed on the display panel, when the burn-in test is performed, a maximum display luminance or a specific gray scale can be fixed in advance, that is, a preset data voltage signal is input to the display panel to control the display panel to display the maximum display luminance or the specific gray scale, the luminous efficiency of the light emitting element 7, the relationship between the current signal fed back by the transparent photosensitive element and the luminous luminance of the light emitting element 7 in the display panel can be monitored as the service time increases, and L ═ I · η can be obtained by monitoring the luminous efficiency of the light emitting element 7 in the display panel, wherein L represents the luminous luminance, I represents the current signal fed back by the transparent photosensitive element RL, and η represents the luminous efficiency of the light emitting element 7, and when the Gamma test is performed, the voltage value of the data signal required for the light emitting element 7 can be obtained by performing the corresponding relationship between the luminous efficiency of the light emitting element 7 and the corresponding voltage signal RL, that is different from the corresponding data voltage value of the luminous element and the corresponding data signal obtained when the burn-in and Gamma test and the Gamma test.

Therefore, as the service life of the display panel is prolonged, the luminous efficiency of the light-emitting element 7 is attenuated, the luminous brightness is reduced, the current intensity required to be increased when the brightness is required to be increased is obtained according to the attenuation value of the luminous brightness, and the corresponding compensation data signal can be obtained according to the current intensity required to be increased.

After receiving the difference signal, the second control unit 21 may query the correspondence between the difference signal and the compensation data signal stored in the storage subunit according to the difference signal, so as to obtain a compensation data signal corresponding to the difference signal, and transmit the compensation data signal back to the first control unit 20.

The transparent photosensitive element RL provided by the above embodiment has various types, as long as the transparent photosensitive element RL can be illuminated under different brightness, and the corresponding resistance values are different, for example, the transparent photosensitive element RL may be configured to include a transparent photosensitive adhesive pattern, and the transparent photosensitive adhesive pattern is doped with a photosensitive resistance material.

Specifically, a photo-resistance material such as sulfide, selenide and/or telluride may be added to the transparent photosensitive paste to form a mixed material, and the mixed material is used to form a transparent photosensitive paste film, then, the transparent photosensitive adhesive film is exposed by using a mask plate to form a transparent photosensitive adhesive film retaining area and a transparent photosensitive adhesive film removing area, wherein the transparent photosensitive adhesive film retention area corresponds to the area where the transparent photosensitive adhesive pattern is located, the transparent photosensitive adhesive film removal area corresponds to other areas except the area where the transparent photosensitive adhesive pattern is located, and developing the exposed transparent photosensitive adhesive film by using a developing solution to remove the transparent photosensitive adhesive film in the transparent photosensitive adhesive film removal area, and finally curing the transparent photosensitive adhesive film in the transparent photosensitive adhesive film retention area to form a transparent photosensitive adhesive pattern.

The transparent photosensitive glue pattern provided by the embodiment still has a photosensitive function after being formed, namely the resistance value of the transparent photosensitive glue pattern can be changed along with the change of the illumination intensity.

In some embodiments, as shown in fig. 4, the light emitting element 7 provided in the above embodiments includes a first electrode and a second electrode disposed oppositely, and a light emitting layer disposed between the first electrode and the second electrode, and an orthographic projection of the transparent photosensitive element RL on the light emitting element 7 coincides with the light emitting layer. Reference numeral 8 in fig. 4 denotes a substrate.

Specifically, the light emitting element 7 may include a first electrode and a second electrode disposed oppositely, and a light emitting layer disposed between the first electrode and the second electrode, wherein the first electrode may be connected to the driving sub-circuit 1 as an anode of the light emitting element 7, and the second electrode may be connected to a negative electrode of the power supply as a cathode of the light emitting element 7, and in practical applications, the driving sub-circuit 1 obtains a corresponding driving signal according to the original data signal or the target data signal and outputs the driving signal to the first electrode of the light emitting element 7, so that an electric field is generated between the first electrode and the second electrode to drive the light emitting layer disposed between the first electrode and the second electrode to emit light.

The size of the transparent photosensitive element RL can be set according to actual needs, exemplarily, the size of the transparent photosensitive element RL can be set to be larger than, equal to or smaller than the size of the light-emitting layer in the light-emitting element 7, when the size of the transparent photosensitive element RL is set to be equal to the size of the light-emitting layer in the light-emitting element 7, namely when the orthographic projection of the transparent photosensitive element RL on the light-emitting element 7 is overlapped with the light-emitting layer, the transparent photosensitive element RL and the light-emitting layer can be manufactured by using the same mask plate, so that the additional provision of mask plates with other sizes for manufacturing the transparent photosensitive element RL is avoided, resources are better saved, and the production cost is reduced. In addition, the orthographic projection of the transparent photosensitive element RL on the light-emitting element 7 is overlapped with the light-emitting layer, so that the transparent photosensitive element RL can receive light emitted by the light-emitting element 7 in a large area, and the accuracy of feedback signals fed back by the transparent photosensitive element RL is guaranteed.

In addition, when the transparent photosensitive element RL is manufactured, the transparent photosensitive element RL may be manufactured on a surface of the anode of the light emitting element 7 facing away from the light emitting layer or on a surface of the cathode of the light emitting element 7 facing away from the light emitting layer, and more preferably, the transparent photosensitive element RL is arranged on the light emitting side of the light emitting element 7, which is more beneficial to the accuracy of the feedback signal of the transparent photosensitive element RL.

The above-mentioned embodiment provides various structures of the driving sub-circuit 1, and exemplarily, as shown in fig. 3, the driving sub-circuit 1 includes: a driving unit 10, a storage unit 11, a power supply control unit 12, a signal input unit 13, a compensation unit 14, a first reset unit 15, a light emission control unit 16, and a second reset unit 17; the first end of the storage unit 11 is connected with the control end of the driving unit 10, and the second end of the storage unit 11 is connected with the power supply signal input end VDD; the power control unit 12 is respectively connected to the power control terminal DM, the power signal input terminal VDD, and the input terminal of the driving unit 10, and is configured to control to turn on or off the connection between the power signal input terminal VDD and the input terminal of the driving unit 10 under the control of the power control terminal DM; the signal input unit 13 is respectively connected with the input control terminal Gate1, the control sub-circuit 2 and the input end of the driving unit 10, and is used for controlling the connection between the control sub-circuit 2 and the input end of the driving unit 10 to be switched on or off under the control of the input control terminal Gate 1; the compensation unit 14 is respectively connected with the input control terminal Gate2, the control terminal of the driving unit 10 and the output terminal of the driving unit 10, and is used for controlling to switch on or off the connection between the control terminal of the driving unit 10 and the output terminal of the driving unit 10 under the control of the input control terminal Gate 2; the first reset unit 15 is respectively connected to the first reset control terminal reset (n), the control terminal of the driving unit 10 and the reference signal input terminal Init, and is configured to control to turn on or off the connection between the control terminal of the driving unit 10 and the reference signal input terminal Init under the control of the first reset control terminal reset (n); the light-emitting control unit 16 is respectively connected with the light-emitting control terminal EM, the output terminal of the driving unit 10 and the first terminal of the light-emitting element 7, and is configured to control to switch on or off the connection between the output terminal of the driving unit 10 and the first terminal of the light-emitting element 7 under the control of the light-emitting control terminal EM; the second Reset unit 17 is respectively connected to the second Reset control terminal Reset (N +1), the reference signal input terminal Init, and the first terminal of the light emitting element 7, and is configured to control to turn on or off the connection between the reference signal input terminal Init and the first terminal of the light emitting element 7 under the control of the second Reset control terminal Reset (N + 1).

Specifically, the operation of the driving sub-circuit 1 with the above-described structure is as follows:

in the reset phase, the reference signal input terminal Init inputs a reference voltage, and under the control of the first reset control terminal reset (n), the first reset control unit controls to turn on the connection between the control terminal of the driving unit 10 and the reference signal input terminal Init, so that the potential of the control terminal of the driving unit 10 becomes the reference voltage; under the control of the power control terminal DM, the power control unit 12 controls to disconnect the connection between the power signal input terminal VDD and the input terminal of the driving unit 10.

In the data writing stage, the driving unit 10 is in a working state under the control of the reference voltage; under the control of the first reset control terminal reset (n), the first reset control unit controls to disconnect the connection between the control terminal of the driving unit 10 and the reference signal input terminal Init; under the control of the power control terminal DM, the power control unit 12 continues to control to disconnect the connection between the power signal input terminal VDD and the input terminal of the driving unit 10; the control sub-circuit 2 outputs a data voltage Vdata (original data voltage or target data voltage), and the signal input unit 13 turns on the connection between the control sub-circuit 2 and the input terminal of the driving unit 10 under the control of the input control terminal Gate1, and writes the data voltage Vdata into the input terminal of the driving unit 10; meanwhile, under the control of the input control terminal Gate2, the compensation unit 14 controls to turn on the connection between the control terminal of the driving unit 10 and the output terminal of the driving unit 10, so that the data voltage Vdata is written to the control terminal of the driving unit 10 through the driving unit 10 and the compensation unit 14 in sequence until the control terminal of the driving unit 10 becomes Vdata + Vth, where Vth is the threshold voltage of the driving unit 10, and Vdata + Vth is stored in the storage unit 11.

In the light emitting phase, under the control of the input control terminal Gate1, the signal input unit 13 controls to disconnect the connection between the control sub-circuit 2 and the input terminal of the driving unit 10; under the control of the input control terminal Gate2, the compensation unit 14 controls to disconnect the connection between the control terminal of the drive unit 10 and the output terminal of the drive unit 10; under the control of the power control terminal DM, the power control unit 12 controls to turn on the connection between the power signal input terminal VDD and the input terminal of the driving unit 10, and transmits the power signal input from the power signal input terminal VDD to the input terminal of the driving unit 10, and under the combined action of the power signal and Vdata + Vth, the driving unit 10 is in a working state, so as to drive the light emitting element 7 to emit light.

In addition, in the reset phase and the data writing phase, under the control of the light-emitting control terminal EM, the light-emitting control unit 16 controls to disconnect the connection between the output terminal of the driving unit 10 and the first terminal of the light-emitting element 7 (for example: the first terminal of the light-emitting element 7 may be an anode of an OLED, the second terminal of the light-emitting element 7 may be a cathode of the OLED, and the cathode is connected to the negative power supply terminal VSS); in the light emission phase, the light emission control unit 16 controls to turn on the connection between the output terminal of the driving unit 10 and the first terminal of the light emitting element 7 under the control of the light emission control terminal EM.

The second Reset unit 17 controls to disconnect the connection between the reference signal input terminal Init and the first terminal of the light emitting element 7 under the control of the second Reset control terminal Reset (N +1) in the Reset phase and the light emitting phase, and the second Reset unit 17 controls to turn on the connection between the reference signal input terminal Init and the first terminal of the light emitting element 7 under the control of the second Reset control terminal Reset (N +1) in the data write phase.

Further, the specific structure of the driving sub-circuit 1 is as follows:

the driving unit 10 includes a driving transistor DTFT; the storage unit 11 includes a storage capacitor Cst, a first end of the storage capacitor Cst is connected to the gate of the driving transistor DTFT, and a second end of the storage capacitor Cst is connected to the power signal input terminal VDD; the power control unit 12 includes a first transistor T1, a gate of the first transistor T1 is connected to the power control terminal DM, a first pole of the first transistor T1 is connected to the power signal input terminal VDD, and a second pole of the first transistor T1 is connected to the first pole of the driving transistor DTFT; the signal input unit 13 includes a second transistor T2, a Gate of the second transistor T2 is connected to the input control terminal Gate1, a first pole of the second transistor T2 is connected to the control sub-circuit 2, and a second pole of the second transistor T2 is connected to the first pole of the driving transistor DTFT; the compensation unit 14 includes a third transistor T3, a Gate of the third transistor T3 is connected to the input control terminal Gate2, a first pole of the third transistor T3 is connected to the second pole of the driving transistor DTFT, a first pole of the third transistor T3 is connected to the Gate of the driving transistor DTFT, and a second pole of the third transistor T3 is connected to the second pole of the driving transistor DTFT; the first reset unit 15 includes a fourth transistor T4, a gate of the fourth transistor T4 is connected to the first reset control terminal reset (n), a first pole of the fourth transistor T4 is connected to the reference signal input terminal Init, and a second pole of the fourth transistor T4 is connected to the gate of the driving transistor DTFT; the light emission control unit 16 includes a fifth transistor T5, a gate of the fifth transistor T5 is connected to the light emission control terminal EM, a first pole of the fifth transistor T5 is connected to the second pole of the driving transistor DTFT, and a second pole of the fifth transistor T5 is connected to the first terminal of the light emitting element 7; the second Reset unit 17 includes a sixth transistor T6, a gate of the sixth transistor T6 is connected to the second Reset control terminal Reset (N +1), a first pole of the sixth transistor T6 is connected to the reference signal input terminal Init, and a second pole of the sixth transistor T6 is connected to the first terminal of the light emitting element 7.

As shown in fig. 5, an embodiment of the present invention further provides a display device, which includes a source driver chip 4, a central controller chip 3, and a plurality of pixel driving circuits provided in the above embodiments, wherein transparent photosensitive elements RL and driving sub-circuits 1 included in the plurality of pixel driving circuits are distributed in an array; the source driving chip 4 comprises a plurality of first control units 20, the driving sub-circuits 1 in the same column multiplex one first control unit 20, and the driving sub-circuits 1 in the same column are connected with the corresponding first control units 20 through the same data signal transmission line 5; one end of the transparent photosensitive elements RL positioned in the same column is connected with the corresponding first control unit 20 through the same first feedback signal transmission line 6, and the other end of the transparent photosensitive elements RL positioned in the same column is connected with the corresponding first control unit 20 through the same second feedback signal transmission line; the central control chip 3 comprises a second control unit 21, and a plurality of first control units 20 multiplex the second control unit 21.

Specifically, in the display device, the source driver chip 4 and the central controller chip 3 may be bound to an edge region of the display device, the display region in the display device includes a plurality of light emitting elements 7 distributed in an array, and the light emitting elements 7 are in one-to-one correspondence with the driving sub-circuits 1 in the pixel driving circuit and in one-to-one correspondence with the transparent photosensitive elements RL in the pixel driving circuit. It should be noted that the central control chip 3 may be embodied as a Timing Controller (TCON), but is not limited thereto.

The driving sub-circuits 1 distributed in an array can be divided into a plurality of rows and a plurality of columns, the driving sub-circuits 1 positioned in the same column multiplex one first control unit 20, and the driving sub-circuits 1 positioned in the same column are connected with the corresponding first control units 20 through the same data signal transmission line 5; the transparent photosensitive elements RL distributed in an array can be divided into a plurality of rows and a plurality of columns, one end of the transparent photosensitive elements RL positioned in the same column is connected with the corresponding first control unit 20 through the same first feedback signal transmission line 6, and the other end of the transparent photosensitive elements RL positioned in the same column is connected with the corresponding first control unit 20 through the same second feedback signal transmission line.

It should be noted that, when displaying, the display device adopts a progressive scanning driving mode, so that the light emitting elements 7 in the same column are all driven line by line, and the data signal transmission lines 5 are not utilized at the same time, and the transparent photosensitive elements RL only feed back the corresponding feedback signals when the corresponding light emitting elements 7 emit light, so that the transparent photosensitive elements RL in the same column also feed back the feedback signals line by line, and therefore, the transparent photosensitive elements RL in the same column do not generate the feedback error problem because the same first feedback signal line and the same second feedback signal line are multiplexed. In addition, a digital-to-analog conversion unit may be integrated into the central control chip 3 to facilitate the conversion process of the feedback signal and the compensation data signal by the second control unit 21.

In addition, when the display device is actually used, the source driving chip 4 and the central control chip 3 can control the transparent photosensitive element RL to monitor the luminance of the light-emitting element 7 in real time, or monitor the luminance at a certain specified time, so as to realize real-time compensation of the luminance of the light-emitting element 7, or perform one-time compensation at a certain specified time.

In the pixel driving circuit provided by the embodiment, the detection and compensation of the luminous efficiency of the luminous element 7 are realized through the transparent photosensitive element RL and the control sub-circuit 2, so that the luminous efficiency is reduced, and the luminous element 7 with reduced luminous brightness can also emit light rays meeting preset required brightness.

In addition, in the pixel driving circuit provided by the embodiment, the transparent photosensitive element RL and the light emitting element 7 are stacked, so that the transparent photosensitive element RL does not occupy the space around the light emitting element 7, and therefore, when the display device provided by the embodiment of the invention comprises the pixel driving circuit, the transparent photosensitive element RL does not affect the pixel aperture ratio of the display device, the pixel aperture ratio of the display device can be maximized, and the display device has higher brightness under the same driving signal, thereby achieving the effect of low power consumption. Moreover, since the aperture ratio is maximized, a lower current is required in achieving the target luminance than in other display devices, and the reduction of the current also contributes to the extension of the life of the light emitting element 7, thereby extending the life of the display device.

In addition, in the display device provided in the embodiment of the present invention, a plurality of first control units 20 are integrated in the source driver chip 4, a plurality of second control units 21 are integrated in the central controller chip 3, and the driving sub-circuits 1 located in the same column are configured to multiplex one first control unit 20, and the driving sub-circuits 1 located in the same column are connected to the corresponding first control unit 20 through the same data signal transmission line 5; one end of the transparent photosensitive elements RL positioned in the same column is connected with the corresponding first control unit 20 through the same first feedback signal transmission line 6, and the other end of the transparent photosensitive elements RL positioned in the same column is connected with the corresponding first control unit 20 through the same second feedback signal transmission line; and a plurality of first control units 20 multiplexing a second control unit 21; the display device has a simple structure while ensuring the normal display function and the brightness compensation adjustment function, thereby being more beneficial to the pixel aperture ratio of the display device and simplifying the manufacturing process of the display device.

The display device may be: any product or component with a display function, such as a television, a display, a digital photo frame, a mobile phone, a tablet computer, etc., wherein the display device may further include a flexible circuit board, a printed circuit board, a back panel, etc.

The embodiment of the present invention further provides a driving method of a pixel driving circuit, which is applied to the pixel driving circuit provided in the above embodiment, and the driving method includes:

a transparent photosensitive element RL in the pixel driving circuit senses the change of the luminous brightness of the luminous element 7 and feeds back a feedback signal to the control sub-circuit 2;

the control sub-circuit 2 adjusts the original data signal to be input to the driving sub-circuit 1 according to the feedback signal, and outputs the adjusted target data signal to the driving sub-circuit 1;

the driving sub-circuit 1 drives the light emitting element 7 to emit light according to the target data signal.

Specifically, the driving sub-circuit 1 is connected to the light emitting element 7, and configured to drive the light emitting element 7 to emit light according to the received data signal, and specifically, may output an original driving signal to the light emitting element 7 according to an original data signal, so as to drive the light emitting element 7 to emit light; a target driving signal may be output to the light emitting element 7 according to the target data signal to drive the light emitting element 7 to emit light. The control sub-circuit 2 is respectively connected with the driving sub-circuit 1 and the transparent photosensitive element RL, on one hand, the control sub-circuit 2 can receive a feedback signal fed back by the transparent photosensitive element RL, and the feedback signal can be a current signal specifically; on the other hand, the control sub-circuit 2 can adjust the original data signal to be input to the driving sub-circuit 1 according to the feedback signal, and output the adjusted target data signal to the driving sub-circuit 1.

When the pixel driving circuit is driven by adopting the driving method provided by the embodiment of the invention, the control sub-circuit 2 outputs an original data signal to the driving sub-circuit 1; the driving sub-circuit 1 outputs an original driving signal to the light emitting element 7 according to the original data signal to drive the light emitting element 7 to emit light; the transparent photosensitive element RL senses the change of the luminance of the light-emitting element 7 and feeds back a feedback signal to the control sub-circuit 2; when the feedback signal shows that the light-emitting element 7 has attenuation, the control sub-circuit 2 adjusts the original data signal input to the driving sub-circuit 1 according to the feedback signal to obtain a target data signal, and outputs the target data signal to the driving sub-circuit 1; the driving sub-circuit 1 outputs a target driving signal to the light emitting element 7 according to the target data signal to drive the light emitting element 7 to emit light.

Therefore, when the pixel driving circuit is driven by the driving method provided by the embodiment of the invention, the detection and compensation of the luminous efficiency of the luminous element 7 are realized through the transparent photosensitive element RL and the control sub-circuit 2, so that the luminous efficiency is reduced, and the luminous element 7 with reduced luminous brightness can also emit light rays meeting the preset required brightness.

In some embodiments, when the control sub-circuit 2 comprises: when the first control unit 20 and the second control unit 21 are connected, the step of adjusting the original data signal to be input to the driving sub-circuit 1 by the control sub-circuit 2 according to the feedback signal, and outputting the adjusted target data signal to the driving sub-circuit 1 specifically includes:

the first control unit 20 compares the feedback signal with a preset reference signal, determines a difference signal, and transmits the difference signal to the second control unit 21 when the difference signal is not equal to 0;

the second control unit 21 determines a compensation data signal according to the difference signal and transmits the compensation data signal back to the first control unit 20;

the first control unit 20 obtains a target data signal from the original data signal and the compensation data signal, and outputs the target data signal to the driving sub-circuit 1.

Specifically, after obtaining the feedback signal, the first control unit 20 may subtract the feedback signal from a preset reference signal to determine a difference signal, where when the feedback signal is the same as the preset reference signal, the difference signal is 0, when the feedback signal is different from the preset reference signal, the difference signal is not 0, and in case that the difference signal is not 0, the first control unit 20 transmits the difference signal to the second control unit 21, and the second control unit 21 determines a compensation data signal according to the difference signal and transmits the compensation data signal back to the first control unit 20; the first control unit 20 may sum the original voltage signal and the compensation voltage signal after obtaining the compensation voltage signal to obtain a target data signal, i.e. a target voltage signal, and then transmit the target data signal to the driving sub-circuit 1, and the driving sub-circuit 1 drives the light emitting element 7 to emit light according to the target data signal.

It should be noted that, in the present specification, all the embodiments are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, as for the method embodiments, since they are substantially similar to the product embodiments, they are described simply, and reference may be made to the partial description of the product embodiments for relevant points.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, it can be "directly on" or "under" the other element or intervening elements may be present.

In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A pixel driving circuit for driving a light emitting element to emit light, comprising:

a driving sub-circuit connected to the light emitting element;

2. The pixel driving circuit according to claim 1, wherein the control sub-circuit comprises: the first control unit and the second control unit are connected; wherein,

3. The pixel driving circuit according to claim 2, wherein the second control unit further comprises a storage subunit configured to store a correspondence between the difference signal and the compensation data signal.

4. The pixel driving circuit according to claim 1, wherein the transparent photosensitive element comprises a transparent photosensitive glue pattern, and the transparent photosensitive glue pattern is doped with a photoresistive material.

5. The pixel driving circuit according to claim 1, wherein the light emitting element comprises a first electrode and a second electrode disposed opposite to each other, and a light emitting layer disposed between the first electrode and the second electrode, and an orthographic projection of the transparent photosensitive element on the light emitting element coincides with the light emitting layer.

6. The pixel driving circuit according to any one of claims 1 to 5, wherein the driving sub-circuit comprises:

a drive unit for driving the motor to rotate,

7. The pixel driving circuit according to claim 6,

the driving unit includes a driving transistor;

8. A display device, comprising a source driver chip, a central controller chip, and a plurality of pixel driving circuits according to any one of claims 1 to 7, wherein the transparent photosensitive elements and the driving sub-circuits included in the plurality of pixel driving circuits are distributed in an array;

9. A driving method of a pixel driving circuit, applied to the pixel driving circuit according to any one of claims 1 to 7, the driving method comprising:

10. The driving method of the pixel driving circuit according to claim 9, wherein when the control sub-circuit comprises: when the first control unit and the second control unit are connected, the step of adjusting the original data signal to be input to the driving sub-circuit by the control sub-circuit according to the feedback signal and outputting the adjusted target data signal to the driving sub-circuit specifically comprises: