CN114429749A

CN114429749A - Active light-emitting element detection and reverse compensation circuit

Info

Publication number: CN114429749A
Application number: CN202210125846.2A
Authority: CN
Inventors: 黄浩; 马毅; 刘家朝
Original assignee: Xi'an Xinyuan Micro Technology Co ltd
Current assignee: Xi'an Xinyuan Micro Technology Co ltd
Priority date: 2022-02-10
Filing date: 2022-02-10
Publication date: 2022-05-03
Anticipated expiration: 2042-02-10
Also published as: CN114429749B

Abstract

The invention provides an active light-emitting element detection and reverse compensation circuit, which belongs to the field of light-emitting element compensation circuits and comprises an external compensation unit, an external detection data collection unit, an external driving unit and P × S multiple detection compensation driving units. The invention aims at the initial T0 of the light-emitting element to perform brightness compensation among light-emitting element modules, and the brightness of the light-emitting element is compensated by a voltage compensation mode. Compensating the brightness of the light-emitting element by a voltage compensation mode aiming at the influence of the aging of the light-emitting element along with the time; finally, compensation can be performed for each light-emitting element module. The influence of the Vth shift of the element on the brightness of the light-emitting unit (light-emitting element) is reduced by the characteristics of different driving unit switching and Vth reverse compensation.

Description

Active light-emitting element detection and reverse compensation circuit

Technical Field

The invention belongs to the field of a light-emitting element compensation circuit, and particularly relates to an active light-emitting element detection and reverse compensation circuit.

Background

Micro/Mini LED and OLED technologies are one of the display technologies that manufacturers of liquid crystal display panels are actively developing in recent years. The biggest difference from the traditional LED backlight technology is that more and smaller (micron grade) LED wafers are used in the backlight design, and a TFT Liquid Crystal Display (LCD) panel matched with the Micro or Mini LED backlight technology has the advantages of high dynamic contrast (HDR), thinness, high brightness and the like, so that the TFT Liquid Crystal Display (LCD) panel has the display image quality close to that of an organic light emitting diode display (OLED) and is lower in price than that of the OLED display.

The Micro LED technology is the same as the OLED technology, each pixel display is driven by an independent Micro LED to emit light, taking UD (3840X 2160) resolution products of common RGB display as an example, the total pixel is 2488.32 ten thousand pixels, which means that the Micro LED backlight also has the same number of LED chips to correspond to each pixel, so how to realize the mass transfer of LEDs to the backlight design is a big subject of the technology.

Since Micro LED process technology has not yet developed, the concept of Mini LED backlight design has also been proposed. Compared with Micro LED technology, the backlight design uses fewer LED chips, and for UD resolution products, the Micro LED needs 2488.32 ten thousand LED chips, but the Mini LED only needs thousands to several tens of thousands of LED chips for backlight design, and although the performance of HDR, brightness, etc. is inferior to that of the Micro LED, the technical difficulty is low, and the image quality of the LCD liquid crystal display can be improved, which has become one of the key development technologies of liquid crystal display panel manufacturers.

The current-driven light-emitting element generally has two driving modes: passive drive (PM) and Active drive (AM). In the design of Active Matrix (AM) driving circuit, each light emitting device has its own independent driving circuit, the driving current is provided by the driving device, at least two devices are used in each pixel circuit to control the output current, and T1 is the driving device to control the on or off of the pixel circuit. T2 is a control element, which is connected to a voltage source to provide a steady current to the light emitting element. However, the circuit design is affected by the aging problem of the device, which causes the brightness decay problem of the circuit driving and the light emitting device, and cannot achieve a long enough service life.

The first problem is that the luminance of the light emitting element itself is also deteriorated with time, and the current-corresponding voltage value on the light emitting element is also changed with time while the luminance of the light emitting element is changed.

The other is that, for each liquid crystal display panel manufacturer, it is most desirable to design a driving circuit of a light emitting element on a glass substrate and drive the light emitting element by a thin film element (TFT) on the substrate. Currently, most panel manufacturers still use amorphous silicon (a-Si) as the thin film device (TFT) semiconductor active layer, and if the light emitting device driving circuit is driven by using a-Si TFT devices, the threshold voltage (Vth) of the TFT devices shifts by Δ Vth under long-time high-voltage operation, which causes variation in the driving current of the light emitting device, and further affects the light emitting efficiency of the light emitting device.

I_LED∝(VGS-Vth)²

In the latest design, no matter the OLED technology or the Micro and Mini LED technology, the light emitting device needs to be driven by the active device on the glass substrate, wherein the circuit design of the active device is very critical, and how to maintain the brightness of the light emitting device to be uniform and the problem that the brightness of the light emitting device is not greatly attenuated after aging is urgently needed to be solved. To address this problem, the present invention provides an active light emitting device detection and reverse compensation circuit.

Disclosure of Invention

In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides an active light emitting device detection and reverse compensation circuit.

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

a detection and reverse compensation circuit for active light-emitting device comprises an external compensation unit, an external detection data collection unit, an external driving unit, and P S detection compensation driving units; the detection compensation driving units are arranged in a matrix, P is the number of matrix columns, and S is the number of matrix rows;

the external detection data collection unit sends the Vsense (the Vsense detection signal is obtained from the detection abnormal drive unit and is output to the external compensation unit for recording and storing) data to the external compensation unit to record the Vsense voltage value;

the external compensation unit calculates a voltage value and transmits the voltage value to the external driving unit;

the external driving unit provides circuit signals for the light-emitting element back plate according to the received pressure value.

The P S detection compensation driving units are switching element circuits for providing driving voltage and current for the light emitting elements.

Preferably, the external compensation unit includes a VdataT0 compensation table, a Vdata/Vsense voltage correspondence table DVV, a VsenseTn measurement table, a VsenseTn +1 measurement table, and a light-emitting device current-voltage correspondence table.

Preferably, the circuit signals supplied by the external driving unit to the light emitting device backplane include VDD, Vdata, Vcomp and Vc signals.

Preferably, the P × S detection compensation driving units include more than 1 detection compensation driving unit group of real-time detection compensation circuits, wherein the multi-stage real-time detection compensation circuits are connected in parallel.

Preferably, the active light emitting element and the real-time detection compensation circuit of the real-time detection compensation circuit are matched with a signal compensation mode, and a single set of detection compensation driving unit comprises four subunits, namely, a first subunit and a second subunit;

a first subunit comprising a first drive unit and a second drive unit: the light source is used for supplying current to the light-emitting element and controlling the brightness of the light-emitting element;

the second subunit is a detection unit: when the circuit is used, the voltage value on the light-emitting element can be fed back in real time to confirm whether the brightness of the light-emitting element is aged or not;

the third sub-unit, the inverse compensation unit: the problem that a switching element in the circuit is aged due to the shift of time Vth is compensated reversely, so that the current of a light-emitting element is prevented from being reduced;

fourth subunit test unit: the method is used for testing the voltage and current data corresponding to the brightness of the light-emitting element before delivery.

Preferably, the first subunit is a driving unit including M groups of driving elements and N light emitting elements, and the first subunit includes T1L/R, T2L/R, a capacitor CL/R element and a light emitting element; four groups of signals Vc1, Vc2, Vdata1 and Vdata2 control four elements T1L/R and T2L/R, and a VDD signal provides light-emitting current source voltage of the light-emitting element for the T2L/R;

wherein M is more than or equal to 4 and more than or equal to 2, and N is more than or equal to 6 and more than or equal to 1.

Preferably, the second subunit is a T4L/R-containing element; the gate switch of the T4L/R device is controlled by Vc5 and Vc6 to transmit the detection signals of Vsense1 and Vsense2 to the external detection data collection unit.

Preferably, said third subunit comprises a T3L/R element; the gate switch of the T3L/R element is controlled by Vc3 and Vc4, and the compensation voltage of Vcomp1 and Vcomp2 is transmitted to T2L/R for reverse compensation.

Preferably, the fourth subunit is configured to test voltage and current data corresponding to the brightness of the light emitting element before leaving a factory; the fourth subunit comprises a T5 element; the gate switch of the T5 device is controlled by the SC signal.

Preferably, the detection compensation driving unit comprises two groups of driving switches T2L/T2R and four groups of control switches T1L/T1R/T3L/T3R;

a. wherein, only one group of driving switch gate stage is driven by the input gray scale voltage Vdata at the same time, and the other group of driving switch gate stage is compensated by the input reverse compensation voltage Vcomp; the driving time ratio of the two groups of driving switches is 1: (1 +/-10%);

b. each group of driving switches is matched with two groups of control switches T1/T3, one group of control gray scale voltage Vdata is input to a gate of the driving switch, the other group of control reverse compensation voltage Vcomp is input to the gate of the driving switch, only one group of control switches is turned on at the scanning time of the stage, and the non-scanning time is that the two groups of control switches are both in a closed state.

Preferably, the detection compensation driving unit includes two sets of detection switches T4L/T4R, wherein when one set of driving switches is turned on to be in a driving state, a corresponding set of detection switches T4L/T4R is turned on, and outputs the detection signal Vsense to the external detection data collection unit.

Preferably, the external detection data collecting unit includes a plurality of receiving switches SWrx and reset switches SWrst and Crx devices and Vsense signals;

wherein, in the single-stage detection time, the reset switch SWrs is turned on, the receiving switch is turned off, and the read data is turned off, so as to discharge Crx; then turning on the receiving switch, turning off the reset switch and turning off the read data, and receiving the Vsense signal; then, the Crx voltage data is read, and the reset switch and the receiving switch are turned off.

Preferably, the external detection data collection unit is disposed on the glass back plate.

Preferably, the source input and the gate of the detection switch have the same voltage at the non-detection time Vc5/Vc 6.

Preferably, the external detection data collection unit is reduced to P/i level; wherein i is the Vsense data collection of the external detection circuit set responsible for several columns of detection compensation driving units;

wherein, within the single-stage detection time, there are i cycles, each cycle includes a reset switch, a receiving switch and a read data.

Preferably, the operation characteristics of the measuring method of the light emitting device voltage current mapping table of the test unit are as follows:

the signals Vc5 or Vc6 and SC are High, the ls current source outputs current, the other signals are low, and the components T4L or T4R and T5 are turned on;

b. controlling the output current of the ls current source, and simultaneously measuring the brightness of the light-emitting component by the outside to adjust the Vdata voltage to ensure that the overall brightness Is equal, and simultaneously receiving a voltage value from the Vsense1 or Vsense2 end of T4L or T4R to obtain the voltage current corresponding to the Vsense/IS light-emitting component.

Preferably, the Vsense/Vdata voltage mapping table measuring method of the test unit has the following operation characteristics:

vc1 or Vc2 is High, and the switch of T1L or T1R is opened and the voltage of Vdata1 or Vdata2 is used for controlling T2L or T2R to determine the current value of the light-emitting component;

b. when the output current of the T2L or T2R current source is controlled, the Vsense1 or Vsense2 end of the T4L or T4R can receive a voltage value at the same time, and a Vsense1/Vdata1 or Vsense2/Vdata2 voltage corresponding table is obtained.

Preferably, the Vsense/Vdata voltage mapping table is measured by adopting K gray scales for interpolation to calculate the brightness, and K times of cyclic detection are required;

one gray level detection is performed for one detection cycle, which is to measure the Vsense data of the S column; the K gray level detections are performed for K detection cycles.

Preferably, the measuring method of the Vsense/Vdata voltage corresponding table starts a measuring and comparing cycle of the Vsense Tn measuring table and the Vsense Tn +1 measuring table at each startup; when the computer is not turned on again for a long time, the measurement cycle of the Vsense detection table is forced to be executed, and the measurement method 2 is adopted to perform the measurement cycle.

Preferably, the Vdata _ Cn compensation method measured by the Vsense/Vdata voltage correspondence table is as follows:

a. at Tn, Vdata _ Cn and Vsense _ Tn values are obtained after the Vsense/Vdata voltage mapping table measurement mode is completed;

b. performing external detection data collection and reverse compensation tracking at the startup and shutdown time of the backlight module, and recording the latest 3-5 sets of data of the Vsense _ Tn time point in the memory, wherein n is the startup and shutdown times;

c. comparing the Vsense _ T0 and Vsense _ Tn voltage values, it takes a larger Vdata _ Cn value to adjust the Vsense _ Tn value back to Vsense _ T0 (1 ± 10%) for the Vth shift curve T2L/R cell voltage with the same current value to be right.

Preferably, the driving process of the driving unit in the detection compensation driving unit is:

when the light-emitting unit works for TL time by the first driving unit and enters TR time, the second driving unit is switched to continue to drive the light-emitting unit, and the first driving unit enters a Vth compensation mode; on the contrary, when the first driving unit is switched to work, the second driving unit is switched to enter a compensation mode;

the voltages Vcomp1 and Vcomp2 must keep the T2L/R device in an off state during the compensation mode; wherein the states of the T2L and the T2R elements are opposite, but the ratio of the switching time of the elements is 1: (1. + -. 10%).

Preferably, for the driving unit in the detection compensation driving unit, if the working voltage Vdata is a positive value, the compensation voltage Vcomp is a negative value at T0; the compensation voltage Vcomp is-VdataX (1 ± 10%).

Preferably, for the driving unit in the detection compensation driving unit, when the scanning period is Tf, the working time of a single driving unit is Td, and the compensation time is Tcomp, wherein Tcomp is less than or equal to Tf-Td; the compensation time Tcomp is characterized as follows:

a. if Tcomp increases when Vsense _ T (n) is greater than last Vsense _ T (n-1), but Tcomp is less than or equal to 1/(T S);

b. tcomp is shortened when the next Vsense _ T (n) < last Vsense _ T (n-1).

Preferably, the Vcomp voltage reverse compensation method is as follows:

a. if the Vsense _ T (n) is greater than the previous Vsense _ T (n-1), the Vcomp is decreased, and the reverse compensation value is increased;

b. vcomp increases when Vsense _ T (n) is present for the next time < Vsense _ T (n-1) last time, but Vcomp voltage < Vth, which is the switching element opening voltage.

The active light-emitting element detection and reverse compensation circuit provided by the invention has the following beneficial effects:

the brightness compensation among the light emitting element modules is performed for the light emitting element initial T0, and the brightness of the light emitting element is compensated by a voltage compensation mode.

Compensating the brightness of the light-emitting element by a voltage compensation mode aiming at the influence of the aging of the light-emitting element along with the time; the final solution can be made to compensate for each light emitting element module.

The influence of the Vth shift of the element on the luminance of the light emitting unit (light emitting element) is reduced by the characteristics of switching of different driving units and Vth reverse compensation.

When the light emitting element is driven and detected by the Nth-stage driving unit, the working voltage is P (positive or negative), and the rest driving units enter a Vth reverse compensation mode, wherein the compensation voltage is N (if the working voltage is positive, N is negative voltage, and if the working voltage is negative, N is positive voltage).

When the Nth-stage driving unit has large Vth deviation in working time, the luminance compensation of the light-emitting element can be carried out by combining with a reverse compensation circuit.

Drawings

In order to more clearly illustrate the embodiments of the present invention and the design thereof, the drawings required for the embodiments will be briefly described below. The drawings in the following description are only some embodiments of the invention and it will be clear to a person skilled in the art that other drawings can be derived from them without inventive effort.

Fig. 1 is a schematic structural diagram of an active light emitting device detection and reverse compensation circuit according to embodiment 1 of the present invention;

FIG. 2 is a diagram of a detection compensation driving circuit;

FIG. 3 is a diagram of the relationship between the external detection data collection unit and the back plate of the light emitting device;

FIG. 4 is a schematic diagram illustrating the external detection voltage reading the voltage data through the external detection data collecting unit;

FIG. 5 is a timing diagram of external detection;

FIG. 6 is a diagram illustrating a luminance compensation scheme of a light emitting device;

FIG. 7 is a first timing diagram illustrating the measurement operation of the light-emitting device before leaving the factory;

FIG. 8 is a second timing diagram illustrating the measurement operation of the light emitting device before it leaves the factory;

FIG. 9 is a timing diagram of reverse compensation when the light emitting device is turned on;

FIG. 10 is a timing diagram illustrating the T2L/R device inverter compensation at T0;

FIG. 11 is a compensation timing diagram of the T2L/R device inverter circuit at Tn;

FIG. 12 is a schematic circuit diagram of the driving circuit, the detecting circuit and the reverse compensation circuit.

Detailed Description

In order that those skilled in the art will better understand the technical solutions of the present invention and can practice the same, the present invention will be described in detail with reference to the accompanying drawings and specific examples. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

Example 1

To improve the long-term operation of the TFT device, the Vth shift affects the driving current of the light emitting device, resulting in unstable brightness of the light emitting device. The present embodiment provides an active light emitting device detecting and reverse compensating circuit, as shown in fig. 1 to 12, including an external compensating unit, an external detecting data collecting unit, an external driving unit, and a plurality of detecting compensating driving units of P × S; the detection compensation driving units are arranged in a matrix, P is the number of matrix rows, and S is the number of matrix rows.

The external detection data collection unit sends the Vsense (the Vsense detection signal is obtained from the detection abnormal driving unit and is output to the external compensation unit for recording and storing) data to the external compensation unit to record the Vsense voltage value; the external compensation unit calculates a voltage value and transmits the voltage value to the external driving unit; the external driving unit provides circuit signals for the light-emitting element back plate according to the received pressure value. The P S detection compensation driving units are switching element circuits for providing driving voltage and current for the light emitting elements.

In the present embodiment, the external compensation unit includes a VdataT0 compensation table, a Vdata/Vsense voltage correspondence table DVV, a VsenseTn measurement table, a VsenseTn +1 measurement table, and a light-emitting element current voltage correspondence table.

At least five data recording tables are required in the external compensation unit, which correspond to a VdaT 0 compensation table, a Vdata/Vsense voltage correspondence table (DVV), a VsenseTn measurement table, a VsenseTn +1 measurement table, and a light-emitting device voltage current correspondence table.

VdaT 0 compensation table: inputting initial Vdata voltage for T0 time, and corresponding to Vdata _ C0 value after P S level compensation after brightness adjustment; vdata _ C0 ═ LUT1(Vdata, P, S, T0).

And a Vdata/Vsense voltage corresponding table (DVV) for comparing Vdata difference values DeltaV corresponding to different Vsense detection values corresponding to the Vsense values detected corresponding to P × S levels after initial Vdata _ T0 voltage is input at T0 time.

VsenseTn measurement table: detecting a Vsense _ Tn-1 value for the Tn time P × S stage, and correspondingly outputting a Vdata _ Cn compensation value; vsense _ Tn-1 ═ LUT2(Vdata _ Cn, P, S).

VsenseTn +1 measurement table: detecting a Vsense _ Tn value for the Tn time P × S stage, and correspondingly outputting a Vdata _ Cn +1 compensation value; vsense _ Tn ═ LUT3(Vdata _ Cn +1, P, S).

5. The voltage current corresponding table of the light emitting device, which is measured at T0 and how to measure the related data is described in detail later, and the compensation data after aging of the light emitting device is also included in the table.

Wherein, the three groups of tables comprise D groups of gray scale recording tables, and each table comprises P S levels; but the subdivision can increase the table stock removal amount, so the table size can be simplified into D groups, the resolution is reduced to p s level, wherein the three groups of tables all contain D groups of gray scale recording tables, and each table contains PXS level; however, the subdivision increases the amount of tables to be sorted, so the table size can be reduced to d groups, and the resolution is reduced to PXS level.

1. Light-emitting element voltage current correspondence table: the voltage current mapping table of the PXS-grade illuminator measured at T0 is described in detail later.

Vsense/Vdata voltage correspondence table: the table for measuring the voltage mapping table of the Vsense/Vdata of the PXS-grade illuminant at T0 is described in detail later.

3. The light-emitting element measurement current integral corresponds to the aging brightness table: and measuring and recording by using a single light-emitting element in a laboratory.

4. Luminance degradation of light emitting element corresponding to compensation voltage: and measuring and recording by using a single light-emitting element in a laboratory.

In this embodiment, the circuit signals provided by the external driving unit to the back plate of the light emitting device include VDD, Vdata, Vcomp, and Vc signals.

In this embodiment, the P × S detection compensation driving units include more than 1 detection compensation driving unit, wherein the multi-stage real-time detection compensation circuit is a parallel connection structure.

In this embodiment, the active light emitting device and the real-time detection compensation circuit of the real-time detection compensation circuit are matched with a signal compensation method, and a single set of detection compensation driving unit includes four sub-units, respectively;

In this embodiment, the first sub-unit is a driving unit including M groups of driving elements and N light emitting elements, and includes T1L/R, T2L/R, a capacitor CL/R element and a light emitting element; four groups of signals Vc1, Vc2, Vdata1 and Vdata2 control four elements T1L/R and T2L/R, and a VDD signal provides light-emitting current source voltage of the light-emitting element for the T2L/R;

In this embodiment, the second subunit comprises a T4L/R element; the gate switch of the T4L/R device is controlled by Vc5 and Vc6 to transmit the detection signals of Vsense1 and Vsense2 to the external detection data collection unit.

In this embodiment, the third subunit includes a T3L/R element; the gate switch of the T3L/R element is controlled by Vc3 and Vc4, and the compensation voltage of Vcomp1 and Vcomp2 is transmitted to T2L/R for reverse compensation.

In this embodiment, the fourth subunit is configured to test voltage and current data corresponding to the brightness of the light emitting element before leaving a factory; the fourth subunit comprises a T5 element; the gate switch of the T5 device is controlled by the SC signal.

In this embodiment, the detection compensation driving unit includes two sets of driving switches T2L/T2R and four sets of control switches T1L/T1R/T3L/T3R;

In this embodiment, the detection compensation driving unit includes two sets of detection switches T4L/T4R, wherein when one set of driving switches is turned on to be in a driving state, a corresponding set of detection switches T4L/T4R is turned on, and outputs a detection signal Vsense to the external detection data collection unit.

In this embodiment, the external detection data collection unit includes not more than P receiving switches SWrx, reset switches SWrst and Crx devices, and Vsense signals;

In this embodiment, the external detection data collection unit is disposed on the glass back plate.

In this embodiment, the source input and the gate of the non-detection time detection switch Vc5/Vc6 have the same voltage.

In this embodiment, the external detection data collection unit is reduced to P/i level; wherein i is the Vsense data collection of the external detection circuit set responsible for several columns of detection compensation driving units;

In this embodiment, the operation characteristics of the measurement method of the voltage-current mapping table of the light emitting device of the test unit are as follows:

In this embodiment, the Vsense/Vdata voltage mapping table measuring method of the test unit has the following operation characteristics:

vc1 or Vc2 is High, and the switch of T1L or T1R is turned on and Vdata1 or Vdata2 is used for controlling the switch of T2L or T2R to determine the current value of the light-emitting component

In the embodiment, the Vsense/Vdata voltage corresponding table is used for measuring the brightness by adopting K gray scales for interpolation calculation, and K times of cyclic detection are required;

one gray level detection is performed in one detection cycle, and one detection cycle is used for measuring Vsense data of S columns; the K gray level detections are performed for K detection cycles.

In this embodiment, the Vsense/Vdata voltage mapping table measurement method starts a measurement comparison cycle of the VsenseTn measurement table and the VsenseTn +1 measurement table at each startup; when the computer is not turned on again for a long time, the measurement cycle of the Vsense detection table is forced to be executed, and the measurement method 2 is adopted to perform the measurement cycle.

In this embodiment, the compensation method of Vdata _ Cn measured by the Vsense/Vdata voltage mapping table is as follows:

c. comparing the voltage values of Vsense _ T0 and Vsense _ Tn, the same current value for the shifted Vth shift curve T2L/R device voltage requires a larger value of Vdata _ Cn to adjust the Vsense _ Tn back to Vsense _ T0 (1 + -10%).

In this embodiment, the driving process of the driving unit in the detection compensation driving unit is as follows:

In this embodiment, for the driving unit in the detection compensation driving unit, if the working voltage Vdata is a positive value, the compensation voltage Vcomp is a negative value at T0; the compensation voltage Vcomp is-VdataX (1 ± 10%).

In this embodiment, for the driving unit in the detection compensation driving unit, when the scanning period is Tf, the working time of the single driving unit is Td, and the compensation time is Tcomp, where Tcomp is less than or equal to Tf-Td; the compensation time Tcomp is characterized as follows:

b. tcomp is shortened when the next Vsense _ T (n) < last Vsense _ T (n-1).

In this embodiment, the Vcomp voltage reverse compensation method is as follows:

Specifically, in the design of the light-emitting backplane, the present invention provides a plurality of P × S detection compensation driving units, wherein the plurality of detection compensation driving units includes more than 1 detection compensation driving unit, and provides an embodiment of a real-time detection compensation circuit of 9T2C, as shown in fig. 2. The circuit consists of two groups of detection compensation driving units and an LED light-emitting unit, wherein each circuit consists of 9 TFT components and 2 capacitor C components; it is within the scope of the present invention to use three, four, or five sets of … … or more circuit designs.

The detection compensation driving unit has the following working modes:

1. the whole circuit can be divided into two groups of L/R, each group comprises a 4T1C circuit, the two groups of circuits are matched with six groups of signals of Vc1.Vc2.Vc3.Vc4.Vc5 and Vc6 for control, wherein Vc4.Vc5 can be equal to Vc1, and Vc3.Vc6 can be equal to Vc2 and can also be controlled in a time-sharing manner; two sets of signals Vc1/Vc4.Vc2/Vc3 and Vc5/Vc6 need to be reverse signals, only one set of circuit drives the LED at the same time L/R, and the other set of circuit carries out reverse compensation.

At TL time, when Vc1/Vc4/Vc5 is high and Vc2/Vc3/Vc6 is low, the L group of circuits operate in a driving detection mode, and the R group operates in a reverse compensation mode; at TR time, when Vc1/Vc4/Vc5 is low and Vc2/Vc3/Vc6 is high, the L group of circuits operates in the reverse compensation mode, and the R group operates in the drive detection mode.

3. The signals of detecting pull-out Vsense1 and Vsense2 in the circuit can be connected with each other or separated from each other, the signal of Vsense1 needs to be the same as the signal of Vc5 when the signal is not detected, and the signal of Vsense2 needs to be the same as the signal of Vc6 when the signal is not detected; the design can reduce the Vth shift problem of the T4LT4R switching element and improve the detection accuracy of Vsense1 and Vsense 2.

The detection voltage reading method comprises the following steps:

as shown in fig. 3 and 5, the external detection voltage is required to read the voltage data through the external detection data collection unit.

1. The light-emitting component back plate is provided with a P-level external detection data collection circuit unit, and the external detection data collection circuit unit can be designed on the glass back plate, the circuit chip or the PCB control circuit board.

2. After all the Vsense1 and Vsense2 signals of the light emitting cells in the same column are connected to each other, the detection data collecting circuit unit includes a reset switch SWrst, a receiving switch SWrx, a read switch SWread, a Vc voltage switch SWvc and a Cfb storage capacitor.

3. During the single-stage detection time (scanning time), the reset switch (simultaneously turning off the receiving switch, turning off the reading switch and the Vc voltage switch) is turned on to discharge Crx, the receiving switch (simultaneously turning off the reset switch, turning off the reading switch and the Vc voltage switch) is turned on to receive the Vsense signal, and the Crx voltage data (simultaneously turning off the reset switch, turning off the receiving switch and the Vc voltage switch) is read.

4. The external IC read data is connected out from the read switch, and the voltage data is correspondingly looked up; the external detection data reading time is executed at the time of starting up.

5. If the detection read time is performed between power-on and power-off, the turn-on time of the single-row detection Vfb signal is 1/(fXS) seconds.

6. Wherein f is the scanning frequency of the light emitting element backplane, S is the number of stages of a single row of the light emitting element backplane, and P is the number of stages of a single row of the light emitting element backplane.

The voltage of the Vsense can be maintained to be the same as that of Vc5 or Vc6 during the Vsense non-detection time, or the Vsense non-detection time is not connected with the signal.

The external time-sharing detection reading method comprises the following steps:

1. the circuit in the external detection data collection unit can be reduced to P/i level.

P is the number of stages of a single column of the light emitting device backplane, i is a group of external detection circuits responsible for several columns

3. When the backplane has 200 rows of drivers, every 4 drivers share one external detection circuit, and one has 200/4-50 external driving circuits.

4. The external detection circuit connection method is the same as the previous page description, the external IC read data is connected out from Tfb drain, and the corresponding table look-up voltage data is obtained; the external detection data reading time is executed at the time of starting up.

5. The signal of Vc5 or Vc6 in each light emitting unit is used for time-sharing control to transmit the Vsense signal in each light emitting unit to the external detection data collection unit.

6. If the detection read time is performed between power-on and power-off, the single-row detection Vfb signal is turned on for i/(fXS) seconds.

7. Wherein f is the scanning frequency of the light emitting element backplane, S is the number of stages of a single row of the light emitting element backplane, and P is the number of stages of a single row of the light emitting element backplane.

The voltage of the Vsense is not detected, and the voltage can be maintained to be the same as that of Vc5 or Vc6, or the voltage is not connected.

9. Wherein f is the scanning frequency of the light-emitting element backboard, S is the stage number of a single row of the light-emitting element backboard, and P is the stage number of a single row of the light-emitting element backboard; i is a set of several columns responsible for the external detection circuit.

At T0, the brightness current and voltage current corresponding table measures:

1. measurement method 1:

only the Vc5 and SC signals need to be High, the ls current source outputs current, the other signals are low, and the T4L and T5 elements are turned on.

Controlling the output current of the ls current source, and simultaneously measuring the brightness of the light-emitting element and adjusting the voltage Vdata by the external part to ensure that the overall brightness Is equal, and simultaneously receiving the voltage value at the Vsense1 end of T4L to obtain a Vsense/Is light-emitting element voltage current corresponding table.

2. The measurement method 2:

the value of the current to the light emitting element is determined by turning on T1L with Vc1 and controlling the switching of T2L with Vdata1 voltage.

When the output current of the T2L current source is controlled, the Vsense1 end of the T4L can receive a voltage value at the same time, and a Vsense1/Vdata1 voltage corresponding table is obtained.

The measurement of the above-mentioned method 1 and method 2 can be done or the measurement of the method 2 can be done only.

The method of compensating the luminance of the light emitting element is shown in fig. 6.

At T0, the light-emitting element luminance matching compensation method:

1. when the L-side circuit is operated normally, the Vc1, Vdata1 and VDD signals are High, the T1L/T2L/T4L element is turned on, and the voltage value is pulled out by Vsense to confirm the brightness of the light-emitting element.

2. The luminance of the light-emitting element at each level Is calculated by two tables of the luminance of the light-emitting element corresponding to the Is current and the voltage of the Is current corresponding to the Vsense, and finally, the difference of the luminance of each light-emitting element on the backboard Is adjusted to be minimum by calculating the luminance improvement Vdata1 voltage compensation.

And 3, correcting the T0Vdata1 (the corrected voltage of the LED brightness at T0 is Vdata _ C0).

T0, the luminance-corrected voltage of the light-emitting element is Vdata _ C0.

The Vdata _ C0 voltage corresponds to the light-emitting element luminance as the target luminance X (1 ± 10%).

6. The target brightness is the brightness with higher flatness of the image brightness.

7. Wherein, the voltage compensation mode Vdata2 is Vdata 1.

8. Meanwhile, the external detection circuit records Vdata _ C0 and Vsense _ T0 values.

With the measurement method 1+ the measurement method 2, the measurement action sequence is shown in fig. 7:

1. after the Vsense data of all the light-emitting devices are measured before the factory, the brightness matching value Vdata _ C0 of the light-emitting devices and the corresponding Vsense _ T0 can be obtained when T0 is obtained.

2. When K gray levels are used for interpolation to calculate the brightness, K times of cyclic detection are required.

Only by using the measurement method 2, the measurement time before factory shipment can be reduced, and the measurement action sequence is shown in fig. 8:

Reverse compensation acts during startup:

1. the voltage measurement comparison of Vsense _ Tn and Vdata _ Cn of method 2 can be repeated once again during startup.

2. The above-obtained Vsense _ Tn and Vsense _ T (n-1) are compared with each other for a pressure difference.

3. The obtained differential pressure value is compensated to Vcomp _ Cn through calculation.

When the power is not turned on or off again for a long time, the reverse compensation detection operation can be executed, and the operation timing is shown in fig. 9:

as shown in FIG. 10, at T0, the T2L/R element reverse circuit compensation method:

1. when the driving unit operates in the driving mode, the gate of the T2L or T2R device is a positive voltage signal (Vdata1), such as 10V driving, and after a long time operation, the device threshold voltage Vth will have a rightward shift phenomenon.

ILED∝(VGS-Vth)2

2. When the T2L device driving the LED is operated for a period of time, it is switched to another T2R device driving the light emitting device unit, and the gate of T2L is given a negative voltage signal (Vcomp1), such as-10V, to compensate the Vth of T2L to the left.

3. If the working voltage Vdata1/Vdata 2 is positive, T0Vcomp1/Vcomp2 is negative voltage;

Vcomp1＝-Vdata1X(1±10％)

Vcomp2＝-Vdata2X(1±10％)

4. the states of the T2L and the T2R elements are opposite to each other when the elements are switched on and off, but the ratio of the switching time of the elements is 1: (1. + -. 10%).

As shown in fig. 11, at Tn, T2L/R element reverse circuit compensation method, Vdata1, Cn compensation method:

1. at the time of shipment, T0 has Vdata _ C0 and Vsense _ T0 values.

2, Tn, Vdata1 and Vsense voltage offset will have Vdata _ Cn and Vsense _ Tn values.

3. External detection data collection and reverse compensation tracking are performed during the power-on and power-off time of the backlight module, and the latest 3-5 sets of data of Vsense _ Tn time points are recorded in the memory, wherein n is the number of power-on and power-off times.

4. Comparing the voltage values of Vsense _ T0 and Vsense _ Tn, the same current value for the shifted Vth shift curve T2L/R cell voltage requires a larger value of Vdata _ Cn to adjust the Vsense _ Tn back to Vsense _ T0x (1 + -10%).

Vcomp1/Vcomp2 reverse compensation method:

when the scanning period is Tf, the working time Td of the single driving unit and the compensation time Tcomp are both equal to or less than Tf-Td; the compensation time Tcomp is characterized as follows:

1. tcomp is increased if the current Vsense _ T (n) > last Vsense _ T (n-1), but Tcomp is ≦ 1/(T S).

2. Tcomp is shortened if when Vsense _ T (n) is present < last Vsense _ T (n-1).

3. If Vcomp is decreased when Vsense _ T (n) is greater than the previous Vsense _ T (n-1), the reverse compensation value is increased.

4. Vcomp increases if Vsense _ T (n) is present at the time of Vsense _ T (n) < last Vsense _ T (n-1), but Vcomp voltage < Vth, which is the switching element opening voltage.

Vdata1T0 compensation table and VsenseTn measurement table example: 480X270 resolution of the back plate, and 1024 gray levels of brightness.

When the brightness is divided into 1024(D) levels, it can be reduced to 256(D) gray scale record tables, and other gray scale values are calculated by interpolation.

When the number of backpanel stages (PXS stage) is 480X270, the table is reduced to 240(p) X135(s) by using 4 sets of circuits as one recording point.

The size of the whole recording table is reduced to 240(p), X135(s), X256(d), and the recording data is reduced by 16 times.

The real-time detection compensation circuit driving embodiment of 9T 2C:

signals Vc1/Vc4/Vc5 are high, signals Vc2/Vc3/Vc6 are low:

the L-side circuit drives the light emitting element: when three elements of T1L, T2L and a capacitor CL are actuated, Vc1 is high, and Vc3 is low, T1L is turned on to transmit Vdata1 voltage to T2L gate control T2L to provide current for a light-emitting element to achieve control of brightness, and the L-side circuit is in a driving detection mode at the moment.

An L-side detection circuit: when Vc5 is high, T4L is turned on, after T4L is turned on, the voltage of the light-emitting element can be transmitted from Vsense1, a table look-up mode corresponds to a time table of the current integration aging voltage measured by the light-emitting element, and then Vdata1 voltage is controlled to be compensated by T2L for the current of the light-emitting element.

R side reverse compensation circuit: the gate of T3R is turned on for high from Vc4, and Vcomp2 voltage is transmitted to the gate of T2R to control T2R to enter a reverse compensation state, and the R-side circuit is in a reverse compensation mode.

The next timing is when the Vc1/Vc4/Vc5 signal is low and the Vc2/Vc3/Vc6 signal is high, the circuit switching operation mode on both sides of L/R.

The Vc5 signal can be the same as or separate from Vc1, and the Vsense1 and Vsense2 signals can be connected with each other or separated; at this time, the T4R device is not activated, and the Vsense2 signal is the same as Vc6, thereby avoiding the Vth shift aging problem of the T4R device.

When Vc1 is high, Vc3 must be low; when Vc2 is high, Vc4 must be low.

The state of Vc4 is high, and T2L element needs to be in the state of driving light-emitting element, and T2R element needs to be in the off state.

The Vcomp1 and Vcomp2 voltages are necessary to turn the T2L/R device off.

Wherein the states of the T2L and the T2R elements are opposite, but the ratio of the switching time of the elements is 1: (1. + -. 10%).

Signals Vc1/Vc4/Vc5 are low, signals Vc2/Vc3/Vc6 are high:

the R-side circuit drives the light emitting element: when three elements of T1R, T2R and a capacitor CR are actuated, Vc2 is high, and Vc4 is low, T1R is turned on, the Vdata2 voltage is transmitted to T2R gate to control T2R to supply current to the light-emitting element to achieve the control of brightness, and the R-side circuit is in a driving detection mode at the moment.

R side detection circuit: when Vc6 is high, T4R is turned on, after T4R is turned on, the voltage of the light-emitting element can be transmitted from Vsense2, a table look-up mode corresponds to a time table of the current integration aging voltage measured by the light-emitting element, and then Vdata2 voltage is controlled to be compensated by T2R for the current of the light-emitting element.

L side reverse compensation circuit: the gate of T3L is turned on for high from Vc3, and Vcomp1 voltage is transmitted to the gate of T2L to control T2L to enter a reverse compensation state, and the L-side circuit is in a reverse compensation mode.

The next timing returns to the circuit switching operation mode at both sides of L/R when the signals Vc1/Vc4/Vc5 are high and the signals Vc2/Vc3/Vc6 are low.

The Vc6 signal can be the same as or separate from Vc2, and the Vsense1 and Vsense2 signals can be connected with each other or separated; at this time, the T4L device is not activated, and the Vsense1 signal is the same as Vc5, thereby avoiding the Vth shift aging problem of the T4R device.

When Vc1 is high, Vc3 must be low; when Vc2 is high, Vc4 must be low;

the Vc3 state is high, the T2R element needs to be in the state of driving the light-emitting element, and the T2L element needs to be in the off state;

the Vcomp1 and Vcomp2 voltages are necessary to turn the T2L/R device off;

The above-mentioned embodiments are only preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, and any simple modifications or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims

1. A detection and reverse compensation circuit for active light-emitting device comprises an external compensation unit, an external detection data collection unit, an external driving unit, and P S detection compensation driving units; p is S is a matrix arrangement of the plural detecting compensating drive units, wherein P is a matrix row number, and S is a matrix row number;

the external detection data collection unit sends the Vsense data to the external compensation unit to record the Vsense voltage value;

the external driving unit provides a circuit signal for the light-emitting element back plate according to the received pressure value;

2. The active light-emitting device detection and inversion compensation circuit of claim 1, wherein the external compensation unit comprises a VdaT 0 compensation table, a Vdata/Vsense voltage corresponding table DVV, a VsenseTn measurement table, a VsenseTn +1 measurement table, and a light-emitting device current-voltage corresponding table.

3. The active light-emitting device detecting and reverse compensating circuit of claim 1, wherein the circuit signals provided by the external driving unit to the light-emitting device backplane include VDD, Vdata, Vcomp and Vc signals.

4. The active light emitting device detecting and reverse compensating circuit of claim 3, wherein the P x S plurality of detecting and compensating driver units comprise more than 1 set of detecting and compensating driver units of real-time detecting and compensating circuit, wherein the multi-stage real-time detecting and compensating circuit is connected in parallel.

5. The active light-emitting device detecting and reverse compensating circuit of claim 4, wherein the active light-emitting device and the real-time detecting and compensating circuit of the real-time detecting and compensating circuit are matched with a signal compensating method, and a single set of detecting and compensating driving unit comprises four sub-units;

a first subunit comprising a first drive unit and a second drive unit: the light source is used for providing current for the light-emitting element and controlling the brightness of the light-emitting element;

the second subunit is a detection unit: feeding back the voltage value of the light-emitting element in real time when the circuit is used to confirm whether the brightness of the light-emitting element is aged or not;

the third sub-unit, the inverse compensation unit: reverse compensation is carried out on the aging problem of the switching element in the circuit due to the shift of time Vth, so that the current of the light-emitting element is prevented from being reduced;

6. The active light-emitting device detection and reverse compensation circuit of claim 5, wherein the first sub-unit is a driving unit comprising M sets of driving devices and N light-emitting devices, the first sub-unit comprises a gate switch T1L/R, T2L/R device, a capacitor CL/R device and a light-emitting device; T1L/R and T2L/R elements are controlled by four groups of signals Vc1, Vc2, Vdata1 and Vdata2, and a VDD signal provides a light-emitting current source level voltage of the light-emitting element for a gate switch T2L/R;

7. The active light emitting device detection and inversion compensation circuit of claim 5, wherein the second sub-unit comprises a gate switch T4L/R; the gate switch of the T4L/R device is controlled by Vc5 and Vc6 to transmit the detection signals of Vsense1 and Vsense2 to the external detection data collection unit.

8. The active light emitting device detection and inversion compensation circuit of claim 5, wherein the third sub-unit comprises a gate switch T3L/R; the gate switch T3L/R is controlled by Vc3 and Vc4, and the compensation voltage of Vcomp1 and Vcomp2 is transmitted to T2L/R for reverse compensation.

9. The active light-emitting device detecting and reverse compensating circuit of claim 5, wherein the fourth sub-unit is configured to test voltage-current data corresponding to the brightness of the light-emitting device before leaving a factory; the fourth subunit includes a control switch T5; the gate switch of the T5 device is controlled by the SC signal.

10. The active light-emitting device detecting and reverse compensating circuit of any one of claims 3 to 8, wherein the detecting and compensating driving unit comprises two sets of driving switches T2L/T2R and four sets of control switches T1L/T1R/T3L/T3R;

a. wherein, only one group of driving switch gate-level is input with gray scale voltage Vdata as a driving state, and the other group of driving switch gate-level is input with reverse compensation voltage Vcomp as a compensation state at the same time; the driving time ratio of the two groups of driving switches is 1: (1 +/-10%);

11. The active light emitting device detection and inversion compensation circuit of claim 10, wherein the detection compensation driving unit comprises two sets of detection switches T4L/T4R, wherein when a set of driving switches is turned on to be in a driving state, a corresponding set of detection switches T4L/T4R is turned on, outputting a detection signal Vsense to the external detection data collecting unit.

12. The active light emitting device detection and inversion compensation circuit of claim 1, wherein the external detection data collection unit comprises a plurality of receiving switches SWrx and reset switches SWrst, Crx devices and Vsense signals;

13. The active light emitting device detection and inversion compensation circuit of claim 1, wherein the external detection data collection unit is disposed on the glass backplane.

14. The active light-emitting device detecting and reverse compensating circuit of claim 11, wherein the source input and the gate of the detecting switch have the same voltage at non-detecting time as Vc5/Vc 6.

15. The active light emitting device detection and inversion compensation circuit of claim 1, wherein the external detection data collection unit is reduced to P/i level; wherein i is the Vsense data collection of the external detection circuit set responsible for several columns of detection compensation driving units;

16. The active light-emitting device detection and reverse compensation circuit of claim 9, wherein the behavior of the light-emitting device voltage current mapping table of the test unit is characterized by:

vc5 or Vc6 and SC signal is High, ls current source outputs current, T4L or T4R and T5 element are turned on;

b. controlling the output current of the ls current source, and simultaneously measuring the brightness of the light-emitting component by the outside to adjust the Vdata voltage to ensure that the overall brightness Is equal, and simultaneously receiving a voltage value from the Vsense1 or Vsense2 end of T4L or T4R to obtain a Vsense/Is light-emitting component voltage current corresponding table.

17. The active light-emitting device detecting and reverse compensating circuit of claim 9, wherein the Vsense/Vdata voltage mapping table of the test unit is characterized by:

18. The active light-emitting device detecting and reverse compensating circuit of claim 16 or 17, wherein the Vsense/Vdata voltage mapping table is measured by interpolating with K gray levels to calculate brightness for K cycles;

19. The active light-emitting device detecting and reverse compensating circuit of claim 16, wherein the Vsense/Vdata voltage mapping table measuring method starts a measurement comparison cycle of the VsenseTn measuring table and the VsenseTn +1 measuring table at each power-on; when the computer is not restarted for a long time, the measurement cycle of the Vsense detection table is forced to be executed.

20. The active light-emitting device detecting and reverse compensating circuit as claimed in claim 17 or 19, wherein the Vdata _ Cn compensation method measured by the Vsense/Vdata voltage mapping table is as follows:

a. at Tn, after the Vsense/Vdata voltage corresponding table measuring mode is completed, Vdata _ Cn and Vsense _ Tn values are obtained;

c. comparing the voltage values of Vsense _ T0 and Vsense _ Tn, the larger value of Vdata _ Cn required for the same current value for the right Vth shift curve T2L/R cell voltage will adjust the value of Vsense _ Tn back to Vsense _ T0 (1 ± 10%).

21. The active light emitting device detecting and reverse compensating circuit of claim 6, wherein the driving process of the driving unit of the detecting and compensating driving unit is:

the voltages Vcomp1 and Vcomp2 cause the T2L/R element to be in an off state during the compensation mode; wherein the states of the T2L and the T2R elements are opposite to each other, the ratio of the switching time of the elements is 1: (1. + -. 10%).

22. The active light-emitting device detecting and reverse compensating circuit of claim 21, wherein for the driving unit of the detecting and compensating driving unit, if the working voltage Vdata is positive, the compensation voltage Vcomp at T0 is negative; the compensation voltage Vcomp is-VdataX (1 ± 10%).

23. The active light emitting device detecting and reverse compensating circuit of claim 22, wherein for a driving unit in the detecting and compensating driving unit, when the scan period is Tf, the operating time of a single driving unit is Td and the compensation time is Tcomp, wherein Tcomp is smaller than or equal to Tf-Td; the compensation time Tcomp is characterized as follows:

b. tcomp is shortened when the next Vsense _ T (n) < last Vsense _ T (n-1).

24. The active light emitting device detecting and reverse compensating circuit of claim 21, wherein the Vcomp voltage reverse compensating method is as follows:

b. vcomp increases if Vsense _ T (n) is present at the time of Vsense _ T (n) < last Vsense _ T (n-1), but Vcomp voltage < Vth, which is the switching element opening voltage.