CN104021755B - A kind of image element circuit, its driving method and display device - Google Patents
A kind of image element circuit, its driving method and display device Download PDFInfo
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- CN104021755B CN104021755B CN201410219292.8A CN201410219292A CN104021755B CN 104021755 B CN104021755 B CN 104021755B CN 201410219292 A CN201410219292 A CN 201410219292A CN 104021755 B CN104021755 B CN 104021755B
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- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000005070 sampling Methods 0.000 claims abstract description 94
- 230000008859 change Effects 0.000 claims abstract description 22
- 239000010409 thin film Substances 0.000 claims description 59
- 238000006243 chemical reaction Methods 0.000 claims description 25
- 239000000872 buffer Substances 0.000 claims description 15
- 239000003990 capacitor Substances 0.000 claims description 9
- 230000003139 buffering effect Effects 0.000 claims description 2
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- 238000007599 discharging Methods 0.000 description 1
- 238000005401 electroluminescence Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
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Abstract
nullThe invention discloses a kind of image element circuit、Its driving method and display device，In the image element circuit that the embodiment of the present invention provides，When driving module to provide driving voltage for luminescent device，This driving voltage is sampled by sampling module，The driving voltage that processing module samples according to sampling module processes，And the luminosity of the luminescent device prestored is along with the corresponding relation of change and the driving voltage of the time of use，Obtain the compensation voltage corresponding with this driving voltage，The compensation voltage that processing module is determined by compensating module is input to the luminescent device of correspondence，Achieve and use the difference of time that the driving voltage of luminescent device is carried out different compensation functions according to luminescent device，Avoid due to luminescent device along with the brightness increasing the luminescent device using identical driving voltage to occur when driving luminescent device of the time of use can reduce，And the problem that the display brightness of the display floater caused is uneven，Improve the uniformity of display floater display brightness.
Description
Technical Field
The invention relates to the technical field of display, in particular to a pixel circuit, a driving method thereof and a display device.
Background
Currently, in an existing Organic Light emitting display device (OLED), the Light emitting brightness of the OLED device is in direct proportion to the driving current and has an exponential relationship with the driving voltage; in the state of low gray scale display, the driving voltage of the OLED device has a very significant influence on the variation of the light emission luminance thereof. The electrical performance of the OLED device is attenuated with the increase of the use time, and the voltage drop of the OLED device is increased in the use process, that is, with the increase of the use time, the luminance of the OLED device is reduced when the OLED device is driven by the same driving voltage, so that the display luminance is not uniform, and the display effect of the whole image is affected. And the OLED device belongs to current driving, and needs stable current to control light emission, due to process and device aging,the threshold voltage V of the drive transistor of the pixel circuit is reducedthThe non-uniformity exists, so that the display brightness is not uniform due to the change of the current flowing through each pixel point OLED, and the display effect of the whole image is also affected.
Therefore, when designing a pixel circuit, a corresponding internal compensation technique is generally introduced, and a pixel circuit with an internal compensation function, as shown in fig. 1, includes: the driving transistor T1, the switching transistor T2, the input control circuit module, the capacitor C and the OLED device; when the pixel circuit works, the internal compensation circuit is adopted, so that the driving voltage for driving the light-emitting device to emit light is only related to the data signal voltage input at the data signal end and is not related to the threshold voltage of the driving transistor, and the influence of the threshold voltage on the light-emitting device can be avoided.
Therefore, how to alleviate the problem that the electrical performance of the OLED device is degraded with the increase of the usage time and the display effect of the whole image is affected is a problem that needs to be solved by those skilled in the art.
Disclosure of Invention
The embodiment of the invention provides a pixel circuit, a driving method thereof and a display device, which are used for solving the problem of uneven display brightness of a display panel caused by the fact that the brightness of a light-emitting device is reduced along with the increase of the service time.
The embodiment of the invention provides a pixel circuit, which comprises a light-emitting device and a driving module used for providing driving voltage for the light-emitting device, and further comprises: the device comprises a sampling module, a compensation module and a processing module; wherein,
the input end of the sampling module is connected with the output end of the driving module, and the sampling module is used for sampling the driving voltage provided by the driving module;
the input end of the processing module is connected with the output end of the sampling module, and the processing module is used for determining compensation voltage corresponding to the driving voltage according to the driving voltage sampled by the sampling module and the pre-stored corresponding relation between the change of the luminous brightness of the light-emitting device along with the use time and the driving voltage;
the input end of the compensation module is connected with the output end of the processing module, and the compensation module is used for inputting the compensation voltage determined by the processing module to the light-emitting device.
In the pixel circuit provided in the embodiment of the present invention, when the driving module provides the driving voltage for the light emitting device, the sampling module samples the driving voltage, the processing module processes the driving voltage according to the driving voltage sampled by the sampling module, and the pre-stored correspondence between the change of the luminance of the light emitting device along with the use time and the driving voltage obtains the compensation voltage corresponding to the driving voltage, the compensation module inputs the compensation voltage determined by the processing module to the corresponding light emitting device, so as to implement different compensation functions on the driving voltage of the light emitting device according to the difference of the use time of the light emitting device, and avoid the problem of uneven display luminance of the display panel due to the fact that the luminance of the light emitting device is reduced when the light emitting device is driven by the same driving voltage along with the increase of the use time, the uniformity of the display brightness of the display panel is improved.
In a possible implementation manner, in the pixel circuit provided in an embodiment of the present invention, the sampling module includes: a first thin film transistor and a second thin film transistor; wherein,
the grid electrode of the first thin film transistor is electrically connected with a sampling signal control end, and the sampling signal control end is used for controlling the sampling module to be in a conducting state in a sampling time period;
the drain electrode of the first thin film transistor is electrically connected with the source electrode of the second thin film transistor and the output end of the driving module respectively;
the source electrode of the first thin film transistor is electrically connected with the grid electrode of the second thin film transistor;
and the drain electrode of the second thin film transistor is electrically connected with the input end of the processing module.
In a possible implementation manner, in the pixel circuit provided in an embodiment of the present invention, the compensation module includes: third and fourth thin film transistors: wherein,
the grid electrode of the third thin film transistor is electrically connected with a compensation signal control end, and the compensation signal control end is used for controlling the compensation module to be in a conducting state in a compensation time period;
the drain electrode of the third thin film transistor is electrically connected with the source electrode of the fourth thin film transistor and the output end of the processing module respectively;
the source electrode of the third thin film transistor is electrically connected with the grid electrode of the fourth thin film transistor;
and the drain electrode of the fourth thin film transistor is electrically connected with the input end of the light-emitting device.
In a possible implementation manner, in the pixel circuit provided in the embodiment of the present invention, an input end and an output end of the processing module are the same port; and the sampling signal control end or the compensation signal control end drives the corresponding sampling module or compensation module to be in a conducting state in a time-sharing mode.
In a possible implementation manner, the pixel circuit provided in an embodiment of the present invention further includes: the buffer module is connected between the output end of the sampling module and the input end of the processing module and between the input end of the compensation module and the output end of the processing module; the buffer module is used for buffering the driving voltage signal sampled by the sampling module or the compensation voltage signal determined by the processing module.
In a possible implementation manner, in the pixel circuit provided in this embodiment of the present invention, the buffer module includes a capacitor, one end of the capacitor is grounded, and the other end of the capacitor is connected between the output end of the sampling module and the input end of the processing module, and is connected between the input end of the compensation module and the output end of the processing module.
In a possible implementation manner, in the pixel circuit provided in an embodiment of the present invention, the processing module includes:
the analog-to-digital conversion unit is used for converting the analog signal of the driving voltage sampled by the sampling module into a corresponding digital signal;
the storage unit is used for storing the pre-established corresponding relation between the change of the luminous brightness of the luminous device along with the use time and the driving voltage;
the determining unit is used for determining a digital signal of compensation voltage corresponding to the driving voltage according to the digital signal converted by the analog-to-digital conversion unit and a pre-stored corresponding relation between the change of the luminous brightness of the light-emitting device along with the use time and the driving voltage;
and the digital-to-analog conversion unit is used for converting the digital signal of the compensation voltage determined by the determination unit into a corresponding analog signal.
An embodiment of the present invention provides a display device, including any one of the pixel circuits provided in the embodiments of the present invention.
The embodiment of the invention provides a driving method of a pixel circuit, which comprises the following steps:
when the driving module inputs driving voltage to the light-emitting device, the sampling module samples the driving voltage and inputs the sampled driving voltage to the processing module under the control of the sampling signal control end;
the processing module determines a compensation voltage corresponding to the driving voltage according to the driving voltage sampled by the sampling module and a pre-stored corresponding relation between the change of the luminous brightness of the light-emitting device along with the use time and the driving voltage, and inputs the compensation voltage to the compensation module;
and the compensation module inputs the compensation voltage determined by the processing module into the light-emitting device under the control of a compensation signal control end.
In a possible implementation manner, in the above pixel circuit driving method according to an embodiment of the present invention, the determining, by the processing module, a compensation voltage corresponding to the driving voltage according to the driving voltage sampled by the sampling module and a pre-stored correspondence between a change of an emission brightness of the light emitting device with use time and the driving voltage includes:
an analog-to-digital conversion unit in the processing module converts the analog signal of the driving voltage sampled by the sampling module into a corresponding digital signal;
the determining unit in the processing module determines a digital signal of compensation voltage for compensating the light-emitting device according to the digital signal converted by the analog-to-digital conversion unit and a pre-stored corresponding relation between the change of the light-emitting brightness of the light-emitting device along with the use time and the driving voltage;
and a digital-to-analog conversion unit in the processing module converts the digital signal of the compensation voltage determined by the determination unit into a corresponding analog signal.
Drawings
FIG. 1 is a schematic diagram of a pixel circuit using internal compensation in the prior art;
fig. 2 is a schematic structural diagram of a pixel circuit according to an embodiment of the invention;
fig. 3 is a schematic structural diagram of a pixel circuit according to an embodiment of the present invention;
fig. 4 is a timing diagram illustrating operation of a sampling signal control terminal and a compensation signal control terminal in a pixel circuit according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of an analog-to-digital conversion circuit according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a digital-to-analog conversion circuit according to an embodiment of the present invention;
fig. 7 is a graph showing a relationship between the luminance of the light emitting device and the driving voltage according to the embodiment of the present invention;
fig. 8 is a flowchart of a driving method of a pixel circuit according to an embodiment of the invention.
Detailed Description
The following describes in detail specific embodiments of a pixel circuit, a driving method thereof, and a display device according to embodiments of the present invention with reference to the accompanying drawings.
As shown in fig. 2, a pixel circuit provided in an embodiment of the present invention includes a light emitting device 01 and a driving module 02 for providing a driving voltage to the light emitting device, and further includes: the device comprises a sampling module 03, a compensation module 04 and a processing module 05; wherein,
the input end of the sampling module 03 is connected with the output end of the driving module 02, and the sampling module 03 is used for sampling the driving voltage provided by the driving module 02;
the input end of the processing module 05 is connected with the output end of the sampling module 03, and the processing module 05 is used for determining compensation voltage corresponding to the driving voltage according to the driving voltage sampled by the sampling module 03 and the prestored corresponding relation between the light-emitting brightness of the light-emitting device 01 and the driving voltage;
the input end of the compensation module 04 is connected to the output end of the processing module 05, and the compensation module 04 is configured to input the compensation voltage determined by the processing module 05 to the light emitting device.
In specific implementation, in the pixel circuit provided in the embodiment of the present invention, the driving module 02 provides a driving voltage for the light emitting device 01, and when the driving module 02 inputs the driving voltage to the light emitting device 01, the sampling module 03 samples the driving voltage and outputs the sampled driving voltage to the processing module 05; the processing module 05 processes the sampled voltage, determines a compensation voltage corresponding to the driving voltage, and outputs the compensation voltage to the compensation module 04; the compensation module 04 inputs the compensation voltage determined by the processing module 05 to the light emitting device 01.
In the pixel circuit provided in the embodiment of the present invention, when the driving module 02 provides the driving voltage for the light emitting device 01, the sampling module 03 samples the driving voltage, the processing module 05 processes the driving voltage according to the sampling module 03, and the pre-stored correspondence between the change of the light emitting luminance of the light emitting device 01 along with the use time and the driving voltage obtains the compensation voltage corresponding to the driving voltage, and the compensation module 04 inputs the compensation voltage determined by the processing module 05 to the corresponding light emitting device 01, so as to implement different compensation functions for the driving voltage of the light emitting device 01 according to the difference of the use time of the light emitting device 01, thereby avoiding the problem of uneven display luminance of the display panel caused by the fact that the luminance of the light emitting device 01 is reduced when the light emitting device 01 is driven by the same driving voltage along with the increase of the use time, the uniformity of the display brightness of the display panel is improved.
Further, in the pixel circuit provided in the embodiment of the present invention, as shown in fig. 3, the driving module 02 may be the same as the driving module in the prior art, and an internal compensation circuit is adopted, which specifically includes: an input control module, a capacitor Cst, a driving transistor DTFT, and a switching transistor STFT. When the pixel circuit works, the driving module 02 and the compensation module 04 jointly provide a compensated driving voltage for the light emitting device 01 through the node N1; among them, the driving current input to the light emitting device 01 is:
wherein, VSupplement deviceThe compensation voltage output by the compensation module 04. Therefore, through the working process of the pixel circuit, the driving voltage of the light-emitting device 01 is compensated, the problem that the display brightness of the display panel is not uniform due to the fact that the brightness of the light-emitting device 01 is reduced when the light-emitting device 01 is driven by the same driving voltage along with the increase of the service time is solved, and the uniformity of the display brightness of the display panel is improved.
Specifically, the driving transistor DTFT of the driving module 02 may be a P-type transistor or an N-type transistor, which is not limited herein.
Specifically, the light emitting device 01 is generally referred to as an Organic Light Emitting Diode (OLED), but may be other electroluminescent devices, and is not limited thereto.
Further, in an embodiment of the pixel circuit provided in the present invention, in a specific implementation, the sampling module 03 in the pixel circuit, as shown in fig. 3, may specifically include: a first thin film transistor T1 and a second thin film transistor T2; wherein,
the gate of the first thin film transistor T1 is electrically connected to the sampling signal control terminal SW1, and the sampling signal control terminal SW1 is configured to control the sampling module 03 to be in a conducting state during a sampling period;
the drain of the first thin film transistor T1 is electrically connected to the source of the second thin film transistor T2 and the output terminal of the driving module 02, respectively;
the source of the first thin film transistor T1 is electrically connected to the gate of the second thin film transistor T2;
the drain of the second thin film transistor T2 is electrically connected to the input of the processing module 05.
In a specific implementation, in the pixel circuit provided in the embodiment of the present invention, the first thin film transistor T1 and the second thin film transistor T2 of the sampling module 03 may be both N-type transistors or P-type transistors, which is not limited herein. In the following description, taking the first thin film transistor T1 and the second thin film transistor T2 as P-type transistors as an example, when the sampling module 03 provided in the embodiment of the present invention receives a low level signal at the sampling signal control terminal SW1, the first thin film transistor T1 and the second thin film transistor T2 are in a conducting state, and a unidirectional signal path from the output terminal of the driving module 02 to the input terminal of the processing module 05 is formed, that is, the driving voltage output by the driving module 02 is sampled under the control of the sampling signal control terminal SW 1. As can be seen from the connection relationship between the first thin film transistor T1 and the second thin film transistor T2, the signal transmission direction in the sampling module 03 is only unidirectional from the output terminal of the driving module 02 to the input terminal of the processing module 05, and is reversed.
Further, in an embodiment of the pixel circuit provided in the present invention, in a specific implementation, the compensation module 04 of the pixel circuit, as shown in fig. 3, may specifically include: a third thin film transistor T3 and a fourth thin film transistor T4; wherein,
the gate of the third thin film transistor T3 is electrically connected to the compensation signal control terminal SW2, and the compensation signal control terminal SW2 is configured to control the compensation module 04 to be in a conducting state during the compensation period;
the drain of the third thin film transistor T3 is electrically connected to the source of the fourth thin film transistor T4 and the output terminal of the processing module 05, respectively;
the source of the third thin film transistor T3 is electrically connected to the gate of the fourth thin film transistor T4;
the drain of the fourth thin film transistor T4 is electrically connected to the input terminal of the light emitting device.
In a specific implementation, in the pixel circuit provided in the embodiment of the invention, the third thin film transistor T3 and the fourth thin film transistor T4 of the compensation module 04 may be both N-type transistors or P-type transistors, which is not limited herein. In the following, taking the third tft T3 and the fourth tft T4 as P-type transistors as an example, when the compensation signal control terminal SW2 receives a low-level signal, the compensation module 04 provided in the embodiment of the present invention turns on the third tft T3 and the fourth tft T4 to form a unidirectional signal path from the output terminal of the processing module 05 to the input terminal of the light emitting device 01, that is, the compensation voltage output by the processing module 05 is input to the input terminal of the light emitting device 01 under the control of the compensation signal control terminal SW 2. As can be seen from the connection relationship between the third thin film transistor T3 and the fourth thin film transistor T4, the compensation module 04 is only turned on in one direction from the output terminal of the processing module 05 to the input terminal of the light emitting device 01, and is turned off in the opposite direction.
Further, in specific implementation, in the pixel circuit provided in the embodiment of the present invention, the sampling module 03 and the compensation module 04, the driving module 02 and the light emitting device 01 are generally disposed in a display region of the display panel, the processing module 05 is disposed in a non-display region, in order to transmit the sampled and compensated signals to the non-display region, it is necessary to separately dispose outgoing lines, and in order to save the number of wires, an input end and an output end of the processing module 05 may also be disposed as the same port, that is, the output end of the sampling module 03 and the input end of the compensation module 04 are commonly connected to one port of the processing module 05. On the basis of this connection relationship, in order to avoid mutual interference between the sampling module 03 and the compensation module 04, only one of the modules is allowed to be in an operating state at the same time, so that the sampling signal control terminal SW1 or the compensation signal control terminal SW2 is required to drive the corresponding sampling module 03 or compensation module 04 to be in a conducting state in a time-sharing manner, and the operating timings of the sampling signal control terminal SW1 and the compensation signal control terminal SW2 are shown in fig. 4. Therefore, the unidirectional signal flow is ensured, and the sampling process and the compensation process are not interfered by external signals.
In a specific implementation, the pixel circuit provided in the embodiment of the present invention may further include a buffer module 06 connected between the output terminal of the sampling module 03 and the input terminal of the processing module 05, and connected between the input terminal of the compensation module 04 and the output terminal of the processing module 05, as shown in fig. 3, the buffer module 06 may buffer the driving voltage signal sampled by the sampling module 03 or the compensation voltage signal determined by the processing module 05. In this way, the buffer module 06 is adopted to buffer the sampling voltage signal or the compensation voltage signal, on one hand, the signal conversion from current to voltage can be performed, and on the other hand, the buffer module cooperates with the working time sequence of the corresponding sampling signal control end SW1 or the corresponding compensation signal control end SW2 to reduce the refresh frequency of the real-time data read-write for realizing external compensation, thereby reducing the power consumption.
In a specific implementation, as shown in fig. 3, the buffer module 06 in the pixel circuit provided in the embodiment of the present invention may be a capacitor C1, one end a of the capacitor C1 is connected between the output terminal of the sampling module 03 and the input terminal of the processing module 05, and is connected between the input terminal of the compensation module 04 and the output terminal of the processing module 05, and the other end b is grounded. Thus, through the process of charging and discharging the capacitor, the sampling voltage or the compensation voltage is buffered and released, and the driving voltage of the light emitting device 01 can be preferably sampled or compensated, so that the attenuation of the electrical performance of the light emitting device 01 is compensated, and the uniformity of the display brightness of the display system is ensured.
In specific implementation, the processing module 05 in the pixel circuit provided in the embodiment of the present invention, as shown in fig. 3, specifically includes:
the analog-to-digital conversion unit 051 is used for converting the analog signal of the driving voltage sampled by the sampling module 03 into a corresponding digital signal;
a storage unit 052 for storing a correspondence relationship between a change of emission luminance of the light emitting device 01 with use time and a driving voltage, which is established in advance;
a determining unit 053, configured to determine a digital signal of the compensation voltage corresponding to the driving voltage according to the digital signal converted by the analog-to-digital conversion unit 051 and a pre-stored correspondence relationship between a change of the light-emitting luminance of the light-emitting device with the use time and the driving voltage;
a digital-to-analog conversion unit 054, for converting the digital signal of the compensation voltage determined by the determination unit 053 into a corresponding analog signal.
Fig. 5 and fig. 6 respectively show circuit schematic diagrams of the analog-to-digital conversion unit and the digital-to-analog conversion unit, and since the working principle of the analog-to-digital conversion circuit and the digital-to-analog conversion circuit is the same as that of the prior art, repeated description is omitted here.
In practical implementation, the correspondence relationship between the light-emitting luminance of the light-emitting device 01 and the driving voltage, which is stored in the storage unit in the processing module 05 in the pixel circuit according to the embodiment of the present invention, is a corresponding lookup table, which is established according to the VL curve of the light-emitting device 01, that is, the correspondence relationship between the light-emitting luminance of the monochrome of the light-emitting device 01 and the driving voltage over time, as shown in fig. 7, and is stored in the storage unit 052 in advance. The processing module 05 determines a compensation voltage corresponding to the driving voltage according to a lookup table of a correspondence relationship between the variation of the luminance of the light emitting device 01 with the use time and the driving voltage, which is pre-stored in the storage unit 052, and outputs the compensation voltage to the compensation module 04, and the compensation module 04 outputs the compensation voltage to the light emitting device 01 to compensate the driving voltage of the light emitting device 01, so that the attenuation of the electrical performance of the light emitting device is compensated, the problem of uneven display luminance of the display panel caused by the decrease of the luminance when the light emitting device 01 drives the light emitting device 01 with the same driving voltage with the increase of the use time is avoided, and the uniformity of the display luminance of the display panel is improved, thereby ensuring the uniformity of the display luminance of the display system.
Based on the same inventive concept, an embodiment of the present invention further provides a display device, including any one of the pixel circuits provided in the embodiments of the present invention. Because the principle of the display device for solving the problems is similar to that of the pixel circuit, the implementation of the display device can refer to the implementation of the pixel circuit, and repeated details are not repeated.
In a specific implementation, the display device provided in the embodiments of the present invention may be applied to a liquid crystal display panel, and may also be applied to an organic electroluminescence display panel, which is not limited herein. The display device may be a display, a mobile phone, a television, a notebook, an all-in-one machine, etc., and other essential components of the display device are understood by those skilled in the art, and are not described herein nor should they be taken as limitations of the present invention.
Based on the same inventive concept, an embodiment of the present invention further provides a driving method of a pixel circuit, as shown in fig. 8, including the following steps:
s101, when the driving module inputs driving voltage to the light-emitting device, the sampling module samples the driving voltage and inputs the sampled driving voltage to the processing module under the control of the sampling signal control end;
in specific implementation, the sampling module may sample the driving voltage between each frame of the driving voltage input to the light emitting device by the driving module, or may sample the driving voltage within a time of each frame, which is not limited herein;
s102, determining a compensation voltage corresponding to the driving voltage by the processing module according to the driving voltage sampled by the sampling module and a pre-stored corresponding relation between the change of the luminous brightness of the luminous device along with the use time and the driving voltage, and inputting the compensation voltage to the compensation module;
and S103, the compensation module inputs the compensation voltage determined by the processing module to the light-emitting device under the control of the compensation signal control end.
In the driving method of the pixel circuit provided in the embodiment of the present invention, when the driving module provides the driving voltage for the light emitting device, the sampling module samples the driving voltage, the processing module processes the driving voltage according to the sampling module, and obtains the compensation voltage corresponding to the driving voltage according to the pre-stored correspondence between the change of the luminance of the light emitting device along with the use time and the driving voltage, and the compensation module inputs the compensation voltage determined by the processing module to the corresponding light emitting device, so as to implement different compensation functions on the driving voltage of the light emitting device according to the difference of the use time of the light emitting device, and avoid the problem of uneven display luminance of the display panel due to the fact that the luminance of the light emitting device is reduced when the light emitting device is driven by the same driving voltage along with the increase of the use time, the uniformity of the display brightness of the display panel is improved.
In specific implementation, in the above driving method for a pixel circuit provided by the embodiment of the present invention, the processing module determines the compensation voltage corresponding to the driving voltage according to the driving voltage sampled by the sampling module and the pre-stored correspondence between the variation of the light emitting brightness of the light emitting device with the use time and the driving voltage, and may be implemented by:
firstly, an analog-to-digital conversion unit in a processing module converts an analog signal of a driving voltage sampled by a sampling module into a corresponding digital signal;
then, the determining unit in the processing module determines a digital signal of compensation voltage for compensating the light-emitting device according to the digital signal converted by the analog-to-digital conversion unit and the corresponding relation between the change of the light-emitting brightness of the light-emitting device along with the use time and the driving voltage, which are stored in the storage unit in advance;
and finally, a digital-to-analog conversion unit in the processing module converts the digital signal of the compensation voltage determined by the determination unit into a corresponding analog signal.
In the pixel circuit provided by the embodiment of the invention, when the driving module provides the driving voltage for the light-emitting device, the sampling module samples the driving voltage, the processing module processes the driving voltage sampled by the sampling module and the prestored corresponding relation between the change of the luminous brightness of the light-emitting device along with the use time and the driving voltage to obtain the compensation voltage corresponding to the driving voltage, the compensation module inputs the compensation voltage determined by the processing module to the corresponding light-emitting device, so that different compensation functions of the driving voltage of the light-emitting device according to the difference of the use time of the light-emitting device are realized, the reduction of the brightness of the light-emitting device when the light-emitting device is driven by the same driving voltage along with the increase of the use time is avoided, the problem of uneven display brightness of the display panel is caused, and the uniformity of the display brightness of the display panel is improved.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (9)
1. A pixel circuit comprising a light emitting device and a driving module for supplying a driving voltage to the light emitting device, further comprising: the device comprises a sampling module, a compensation module and a processing module; wherein,
the input end of the sampling module is connected with the output end of the driving module, and the sampling module is used for sampling the driving voltage provided by the driving module;
the input end of the processing module is connected with the output end of the sampling module, and the processing module is used for determining compensation voltage corresponding to the driving voltage according to the driving voltage sampled by the sampling module and the pre-stored corresponding relation between the change of the luminous brightness of the light-emitting device along with the use time and the driving voltage;
the input end of the compensation module is connected with the output end of the processing module, and the compensation module is used for inputting the compensation voltage determined by the processing module to the light-emitting device; the light emitting device is an organic light emitting diode;
further comprising: the buffer module is connected between the output end of the sampling module and the input end of the processing module and between the input end of the compensation module and the output end of the processing module;
the buffer module is used for buffering the driving voltage signal sampled by the sampling module or the compensation voltage signal determined by the processing module.
2. The pixel circuit of claim 1, wherein the sampling module comprises: a first thin film transistor and a second thin film transistor; wherein,
the grid electrode of the first thin film transistor is electrically connected with a sampling signal control end, and the sampling signal control end is used for controlling the sampling module to be in a conducting state in a sampling time period;
the drain electrode of the first thin film transistor is electrically connected with the source electrode of the second thin film transistor and the output end of the driving module respectively;
the source electrode of the first thin film transistor is electrically connected with the grid electrode of the second thin film transistor;
and the drain electrode of the second thin film transistor is electrically connected with the input end of the processing module.
3. The pixel circuit of claim 2, wherein the compensation module comprises: a third thin film transistor and a fourth thin film transistor; wherein,
the grid electrode of the third thin film transistor is electrically connected with a compensation signal control end, and the compensation signal control end is used for controlling the compensation module to be in a conducting state in a compensation time period;
the drain electrode of the third thin film transistor is electrically connected with the source electrode of the fourth thin film transistor and the output end of the processing module respectively;
the source electrode of the third thin film transistor is electrically connected with the grid electrode of the fourth thin film transistor;
and the drain electrode of the fourth thin film transistor is electrically connected with the input end of the light-emitting device.
4. The pixel circuit of claim 3, wherein the input and output of the processing module are the same port;
the sampling signal control end and the compensation signal control end drive the corresponding sampling module and the corresponding compensation module to be in a conducting state in a time-sharing mode.
5. The pixel circuit according to claim 1, wherein the buffer module comprises a capacitor having one end connected to ground and the other end connected between the output of the sampling module and the input of the processing module and between the input of the compensation module and the output of the processing module.
6. The pixel circuit according to any of claims 1-5, wherein the processing module comprises:
the analog-to-digital conversion unit is used for converting the analog signal of the driving voltage sampled by the sampling module into a corresponding digital signal;
the storage unit is used for storing the pre-established corresponding relation between the change of the luminous brightness of the luminous device along with the use time and the driving voltage;
the determining unit is used for determining a digital signal of compensation voltage corresponding to the driving voltage according to the digital signal converted by the analog-to-digital conversion unit and a pre-stored corresponding relation between the change of the luminous brightness of the light-emitting device along with the use time and the driving voltage;
and the digital-to-analog conversion unit is used for converting the digital signal of the compensation voltage determined by the determination unit into a corresponding analog signal.
7. A display device comprising the pixel circuit according to any one of claims 1 to 6.
8. A method of driving a pixel circuit according to any one of claims 1 to 6, comprising:
when the driving module inputs driving voltage to the light-emitting device, the sampling module samples the driving voltage and inputs the sampled driving voltage to the processing module under the control of the sampling signal control end;
after the sampling module samples the driving voltage, a cache module caches the driving voltage signal sampled by the sampling module;
the processing module determines a compensation voltage corresponding to the driving voltage according to the driving voltage sampled by the sampling module and a pre-stored corresponding relation between the change of the luminous brightness of the light-emitting device along with the use time and the driving voltage, and inputs the compensation voltage to the compensation module;
after the processing module determines the compensation voltage corresponding to the driving voltage, the buffer module buffers the compensation voltage signal determined by the processing module;
and the compensation module inputs the compensation voltage determined by the processing module into the light-emitting device under the control of a compensation signal control end.
9. The method according to claim 8, wherein the processing module determines the compensation voltage corresponding to the driving voltage according to the driving voltage sampled by the sampling module and a pre-stored correspondence between a change in emission brightness of the light emitting device with use time and the driving voltage, and specifically comprises:
an analog-to-digital conversion unit in the processing module converts the analog signal of the driving voltage sampled by the sampling module into a corresponding digital signal;
the determining unit in the processing module determines a digital signal of compensation voltage for compensating the light-emitting device according to the digital signal converted by the analog-to-digital conversion unit and a pre-stored corresponding relation between the change of the light-emitting brightness of the light-emitting device along with the use time and the driving voltage;
and a digital-to-analog conversion unit in the processing module converts the digital signal of the compensation voltage determined by the determination unit into a corresponding analog signal.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410219292.8A CN104021755B (en) | 2014-05-22 | 2014-05-22 | A kind of image element circuit, its driving method and display device |
| PCT/CN2014/086311 WO2015176420A1 (en) | 2014-05-22 | 2014-09-11 | Pixel circuit, driving method thereof and display device thereof |
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| CN201410219292.8A CN104021755B (en) | 2014-05-22 | 2014-05-22 | A kind of image element circuit, its driving method and display device |
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| CN104021755B true CN104021755B (en) | 2016-09-07 |
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| CN104021755B (en) * | 2014-05-22 | 2016-09-07 | 京东方科技集团股份有限公司 | A kind of image element circuit, its driving method and display device |
| CN107331346A (en) * | 2017-08-18 | 2017-11-07 | 深圳市华星光电半导体显示技术有限公司 | Brightness regulating apparatus and brightness adjusting method, the display device of display device |
| CN111727471B (en) * | 2018-02-23 | 2022-06-03 | 索尼半导体解决方案公司 | Display device, driving method of display device, and electronic apparatus |
| KR102546312B1 (en) * | 2018-09-28 | 2023-06-22 | 엘지디스플레이 주식회사 | Current Sensing Device And Organic Light Emitting Display Device Including The Same |
| CN109147674B (en) | 2018-10-25 | 2020-11-03 | 深圳创维－Rgb电子有限公司 | AMOLED display ghost eliminating method, display terminal and storage medium |
| CN110730534A (en) * | 2019-10-30 | 2020-01-24 | 广东晟合技术有限公司 | OLED product brightness compensation method |
| CN113077750A (en) * | 2019-12-17 | 2021-07-06 | 咸阳彩虹光电科技有限公司 | Method for maintaining brightness of LED, driving circuit and display device |
| CN114038397A (en) * | 2021-08-18 | 2022-02-11 | 重庆康佳光电技术研究院有限公司 | Drive compensation circuit, display device, and method for driving display unit |
| CN114005405A (en) * | 2021-10-19 | 2022-02-01 | 惠州华星光电显示有限公司 | Display panel and brightness compensation method thereof |
| CN115268329B (en) * | 2022-07-29 | 2024-08-23 | 青岛海信宽带多媒体技术有限公司 | Optical module and power supply voltage monitoring compensation method thereof |
| CN116246575B (en) * | 2022-12-23 | 2024-08-06 | 惠科股份有限公司 | Pixel driving circuit, display panel and display device |
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| SG120888A1 (en) * | 2001-09-28 | 2006-04-26 | Semiconductor Energy Lab | A light emitting device and electronic apparatus using the same |
| KR100703500B1 (en) * | 2005-08-01 | 2007-04-03 | 삼성에스디아이 주식회사 | Data driving circuit, light emitting display device and driving method thereof |
| US20070146253A1 (en) * | 2005-12-22 | 2007-06-28 | Au Optronics Corporation | Method and device for brightness stabilization in AMOLED display |
| KR100893482B1 (en) * | 2007-08-23 | 2009-04-17 | 삼성모바일디스플레이주식회사 | Organic light emitting display device and driving method thereof |
| KR100902219B1 (en) * | 2007-12-05 | 2009-06-11 | 삼성모바일디스플레이주식회사 | Organic light emitting display |
| US8299983B2 (en) * | 2008-10-25 | 2012-10-30 | Global Oled Technology Llc | Electroluminescent display with initial nonuniformity compensation |
| CA2688870A1 (en) * | 2009-11-30 | 2011-05-30 | Ignis Innovation Inc. | Methode and techniques for improving display uniformity |
| CN103400545A (en) * | 2011-08-08 | 2013-11-20 | 东莞万士达液晶显示器有限公司 | Pixel circuit |
| CN103280188B (en) * | 2013-06-14 | 2015-09-02 | 电子科技大学 | OLED compensation of ageing system and method |
| CN103578428B (en) * | 2013-10-25 | 2015-12-02 | 华南理工大学 | A kind of driving method of image element circuit of active organic electroluminescent display |
| CN203825990U (en) * | 2014-05-22 | 2014-09-10 | 京东方科技集团股份有限公司 | Pixel circuit and display apparatus |
| CN104021755B (en) * | 2014-05-22 | 2016-09-07 | 京东方科技集团股份有限公司 | A kind of image element circuit, its driving method and display device |
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| CN104021755A (en) | 2014-09-03 |
| WO2015176420A1 (en) | 2015-11-26 |
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