JP6043044B2 - Active matrix display and method thereof - Google Patents

Description

  The present invention relates to an active matrix display and a method for driving a display.

  An active matrix display includes a large number of light emitting units called pixels. Each pixel includes electronic circuitry that controls the light emitting diode. Pixels are arranged in an array of rows and columns to form a display. In operation, each pixel of the array is sequentially programmed with updated data values that are converted to light levels.

  In a typical 2-TFT pixel, the data value that determines the light intensity is supplied externally in the form of a voltage. The voltage is converted to a current by the pixel circuit, which is directed towards an organic light emitting diode (OLED). The amount of current determines the amount of light emitted by the diode. When the OLED is programmed, the thin film transistor (TFT) transmits a data value voltage from the program line to the gate of another transistor that controls the current flowing from the power source to the OLED.

  The current flowing through the current control transistor varies with the voltage at its gate. Factors such as transistor material characteristics directly affect the current through the transistor. As transistor material properties change (mismatch), the current flowing in two different pixels may be different, even at the same program voltage level. This also leads to a difference in light output. In order to deal with this problem, various pixel designs with an increased number of transistors and control lines have been proposed. However, these designs have a complicated structure, and yield and aperture ratio are reduced.

  There is a need for an active matrix display that includes a pixel driver that uses a minimum number of transistors, avoids complex pixel circuitry, enables rapid programming, and improves output uniformity.

  The invention provides an active matrix display with display driver control circuitry that provides a high level of uniformity without increasing the complexity of the display pixels.

  The invention comprises at least one circuit comprising: a plurality of pixels and a data line; a selection line and a current line for the pixel; at least two thin film transistors, a capacitor and a light emitting diode. It can be described as a display that includes a pixel and a circuit that is external to the plurality of pixels and adjusts the voltage of the data line according to the current drawn from the power supply signal to the display.

  In one embodiment, the invention relates to at least one data driver circuit including a column data line and a column current line, and connected to both the column data line and the column current line to connect the column data line voltage. A plurality of pixels including at least one pixel that drives a pixel current to at least one pixel in response to the pixel data line and the head of the column current line and external to the plurality of pixels, the driving pixel current Is an active matrix display that includes a loopback circuit that senses the voltage of and adjusts the column data line voltage to program the adjusted pixel current voltage to match the external reference current.

  In another embodiment, a method for driving an active matrix display senses a differential voltage between a voltage of current drawn by a programmed pixel and a voltage of a first power supply current to the active matrix display. And adjusting the data programming voltage to the pixel of the display according to the difference, the sensing and controlling step being a loopback control at the beginning of the column of pixels containing the pixel and external to the pixels of the column Executed by the circuit.

  In another embodiment, an active matrix display includes a plurality of AMOLED pixels arranged in matrix columns and rows, each column of pixels being connected to a common current line and a common data voltage source. And each row of pixels is connected to a common selection line. Also, at least one pixel is connected to a current drive transistor having a source / drain connected to the drain / source, gate and column current lines, and to a source / drain and column data line connected to the gate of the drive transistor. The plurality of AMOLED pixels includes an address transistor having a drain / source, a select line connected to the gate of the address transistor, and an OLED connected to the drain / source of the current drive transistor. To sense the voltage of the driven pixel current and adjust the column data line voltage to match the adjusted pixel current voltage to the external reference current outside the plurality of pixels in the column. Connected to the loopback control circuit to program .

  In yet another embodiment, the invention is a data driver circuit comprising at least one column data line, at least one parallel column current line, at least one column data line and a corresponding parallel column. A plurality of pixels including at least one pixel connected in series to both of the current lines and driving a pixel current to the at least one pixel in response to the column data line; and a column of the data line and the current line The differential voltage between the voltage of the first input data current and the voltage of the current drawn by the load on the current line is detected at the head and outside the plurality of pixels in the column, and the input data current is adjusted according to the difference. A loopback control circuit.

  In another embodiment, a method of driving an active matrix display includes: (A) sampling an initial current representing a first program data value from a power supply to the active matrix display; and (B). Storing the same first program voltage data value in the second capacitor circuit and supplying the first program voltage data value to the selected pixel circuit; and (C) applied as a result of a change in pixel characteristics. Extracting current according to the next voltage data value subtracted from the first program voltage data value, and (D) detecting the voltage of the extracted current and comparing it with the voltage of the sampled initial current signal And (E) according to the result of the comparison, the first program voltage data value is set to a new program voltage data value in the second capacitor. And (F) supplying a new program voltage data value to the selected pixel; and (G) the stored program voltage data value to be compared is the same as the voltage of the sampled initial current. Steps (B) to (F) are repeated until.

The schematic diagram of a display circuit. Diagram of the display circuit. The schematic diagram of a display circuit. A graph of pixel current and driver current. A graph of pixel current and driver current. The graph which shows the relationship between an electric current and data. A graph showing the percentage of current mismatch shown as a function of data. The graph which shows the relationship between an electric current and data. A graph showing the percentage of current mismatch shown as a function of data.

  The brightness of an AMOLED display depends in part on the current flowing through the OLED element. Each pixel current of one AMOLED element was configured differently for a voltage programmed pixel by applying a voltage to a circuit transistor or for a current programmed pixel. It is programmed to drive a predetermined current by applying a current to the circuit transistor.

  In voltage-programmed displays, voltage-to-current conversion is based on the large signal transconductance of the transistor, which is a quantity representing the ratio of current output to voltage input. The OLED element current varies with the transconductance of the pixel circuit transistor. Transconductance depends on factors such as transistor mobility, which can fluctuate within the display, thereby causing non-uniformity within one display and between displays. Furthermore, voltage programmed pixels are sensitive to transistor threshold voltages, which also vary within the display or between displays.

  The invention relates to a data driver circuit that reduces the complexity of an active matrix backplane and improves AMOLED performance compared to more complex uniform correction mechanisms. The driver is an instruction sequence or programming circuit that controls the display. In one embodiment, the invention provides a data driver for 2-TFT pixels that achieves a high level of uniformity without having to increase the number of pixel transistors or control lines. The data driver operates within a feedback loop formed by data lines and current lines for each column or for multiple columns. The switching circuit discriminates individual pixel currents from the rest of the column currents in the current line. The current sensing circuit then controls the feedback loop to charge the data line until the pixel current reaches the desired level.

  The features of the invention will become apparent from the drawings and the following detailed discussion. These describe preferred embodiments of the invention by way of example only, without limitation. In the drawings, similar structures are denoted by the same reference numerals.

  FIG. 1 is a schematic diagram of a proposed AMOLED display circuit 10. The circuit 10 includes a plurality of pixels 12 arranged in a matrix array. Although FIG. 1 shows a 3 × 3 matrix, this is just one example of an AMOLED and can be formed to include thousands of light emitting pixels 12. The 3x3 matrix is shown as including columns A, B and C and rows R, S and T. Each pixel 12 is located between the intersection of one pixel select line 26 and a pair of column data line 16 and column current line 18. Each of the pixels 12 includes electronic circuitry that controls the light emitting diodes 14.

  Each column includes a data line 16 and a current line 18, and each pixel circuit includes a transistor M 1 20, a transistor M 2 22 and a storage capacitor 24. Transistors 20 and 22 are three terminal (gate, drain and source) devices and behave in two ways. One operates as a switch that allows the passage of information in the form of a voltage, and the other operates as a variable valve that controls the amount of current flowing. In each pixel 12, the transistor M 1 20 is a current driving transistor, and has a drain / source connected to the column current line 18, a source / drain connected to the diode 14, and a gate connected to the source of the transistor M 2 22. . Address transistor M2 22 has its source / drain connected to the gate of drive transistor M1 20 and its drain / source connected to column data line 16. Address transistor M2 22 functions as a switch. When the switch is ON, its drain voltage is sent to the source, and when the switch is OFF, no voltage transmission is allowed. Transistor M1 20 functions as a control valve that can control the flow of current depending on the state of its gate. In principle, the amount of voltage on the gate of transistor M120 determines the current that flows through the device (to or from the drain).

  When updating a column of pixels A, B, or C with new information, the data line 16 provides a data value in the form of a voltage. This is done for one row at a time, and each pixel in the row is supplied with a corresponding data value at the same time. The voltage is converted to a current by transistor M 120 and supplied by current line 18. The current is sent in the direction of the light emitting diode, and the amount of current determines the amount of light emitted. Data to the AMOLED is written to the pixels one row at a time, but the diode operates essentially with a 100% duty cycle. This is accomplished by providing a memory circuit for each pixel supplied through the combination of transistor 22 and capacitor 24.

  In operation, one pixel 12 is selected by pulsing the select line 26. Transistor M2 22 is driven by a pulse on select line 26 and is turned on to the ON position (as shown in FIG. 3). In conventional displays, a new current I is drawn from the column current line 18 while the selected pixel is charged to a stable voltage through the program line 16. Since all other pixels 12 are unselected, a new current I flows through the selected pixel.

  The current flowing through the transistor depends on its gate voltage. However, the material properties of the transistors that make up the array of pixels can vary across the display area. These factors produce uneven brightness levels. Thus, even at the same programmed level, the light output can be different for two different pixels. As a result of pixel characteristic variations, discrepancies occur across the device display.

  The invention provides an external control circuit for a display. This control produces a high level of uniformity without increasing the pixel complexity of the display. The invention achieves a display with higher aperture ratio (brighter display), lower OLED operating voltage, lower power consumption, higher yield and lower production cost. The inventive driver can be incorporated into a standard IC or integrated into the same panel as the active backplane, thereby further reducing display costs.

  FIG. 2 shows diagrammatically the inventive external control circuit 28 provided in combination with the internal pixel 12. The internal circuit of the pixel 12 includes transistors 20 and 22 and a light emitting diode 14. The external control circuit 28 operates in a feedback loop constituted by a data line 16 and a current line 18 at the head of each display circuit, eg, A. 2 and 3, the external control circuit 28 includes a current source / current sensing module 30 combined with a data programming module 32.

  In operation, current source / current sensing module 30 is programmed to discriminate individual pixel currents from the remaining column currents in current line 18 and control an internal feedback loop to achieve a target pixel current level. Control the module 32 Since current sensing and control is performed at the head of the driver train and not within the pixel 12, the mismatch in the material properties of the transistor 20,22 of the pixel is not a disadvantageous factor. In addition, by using the same external control circuit 28 to program all the pixels in a given column, pixel current variations are minimized.

  FIG. 3 is a schematic circuit diagram including the external control circuit 28 of one display according to the invention. Within this application, an “external control circuit” means a control circuit that is connected to or associated with the outside of a pixel of an array. For example, the external control circuit can be located at the beginning of the pixel column within the display circuit. In one array, each pixel column can be associated with its separate external control circuit. In FIG. 3, the current source / current sensing module 30 includes a transistor MSSource 34, a transistor MSsense 36, and an amplifier Amp 1 38. The transistor MSSource 34 is a transistor that supplies current at a low voltage. The transistor MSsense 36 is a transistor that detects a small change in current. The amplifier Amp1 38 controls both the transistors 34 and 36. FIG. 3 shows a single current source / current sensing module 30 with a data programming module 32 combined with a single display row. However, as pointed out above, the combination of current source / current sensing module 30 and data programming module 32 is associated at the head of each of the columns of the display matrix.

  The current source / current sensing module 30 of FIG. 3 provides a control mechanism using an amplifier Amp1 38, transistors MSsense 36 and MSSource 34. Amplifier Amp1 38 has three terminals, two voltage input terminals 46, 48 labeled "+" and "-", and an output terminal 50 that controls the gates of transistor MSsense 36 and transistor MSSource 34. The input terminal 46 is connected to a constant external supply voltage Vcol. The input terminal 48 is connected to the node nc44. Node nc44 remains at a constant voltage Vcol, except for small variations during programming. When switch MS1 40 is ON, the gate voltages of transistor MSsense 36 and transistor MSSource 34 are established by the current flowing through transistors MSsense 36 and MSSource 34 in response to current line 18. As line 18 begins to draw more current, the voltage at node nc44 and input terminal 48 changes accordingly. Thus, in response to a voltage change at any node nc44, the amplifier Amp1 38 controls the gate voltage of the MSsense transistor 36 and the MSSource transistor 34 to control the current voltage through the transistors MSsense 36 and MSSource 34. As a result, the voltage change generated at the output terminal 50 changes the gates of both transistors until the currents supplied by the transistors MSsense 36 and MSSource 34 match the current drawn.

  The change in the gate voltage of the transistor MSsense 36 is directly related to the size of the transistor. Larger transistors can produce larger currents for small gate voltage changes. On the other hand, a small transistor can more precisely control its output current while requiring a larger change in its gate voltage (for a given small current change).

  In FIG. 3, the size of the current source / current sensing module 30, the large transistor MSSource 34, and the small transistor MSsense 36 can be tailored to specific display requirements. These are connected via a switch MS1 40 and controlled by an amplifier Amp1 38. The letter “A” represents one display column. When operation begins, switch MS1 40 is turned on and most of the column current flows through large transistor MSSource 34 (at this point there is no current through the selected pixel). When the switch MS1 40 is turned off, the gate voltage of the large transistor MSSource 34 remains constant by the capacitor CS1 42, and thus the current supplied by the large transistor MSSource 34 also remains constant. This operation is called column current sampling by the transistor MSSource34.

  In FIG. 3, the data programming module 32 is connected to a current source / current sensing module 30. Data programming module 32 includes an amplifier Amp2 52 and a series of switches. Amplifier Amp2 52 has one input 54 connected to capacitor CS2 60 and another input 56 connected to the gate of MSsense transistor MS1 36. Another output terminal 58 is connected to the data line 16 of column A. During the second sampling period, switch transistor MS2 62 samples the gate voltage of small MSsense transistor 36 and stores it in capacitor CS2 60 (which sets the base level indicating the column current and later Used in the comparison process). At this stage, the current source / current detection module 30 is in the standby / detection mode, and the MSsense 36 detects a change in the column current flowing into the node nc44. Amplifier Amp2 52 can control the gate voltage of MSsense transistor 36 accordingly.

  During the programming period, data line 16 is connected to the gate of transistor M1 20 through transistor M2 22. The transistor M1 20 is always connected to the node nc44. This configuration includes a current source / current sensing module 30, a data programming module 32, and a pixel transistor M120, and provides a feedback loop from node nc44 through current line 18 and data line 16. When the external data current Idata64 is injected into the node nc44, the following mechanism is operated in the feedback loop. (I) The gate voltage of the MSsense 36 is changed by the Amp1 38 so as to correspond to the current drawn by the node nc44 (detected current). (Ii) The negative input voltage of Amp2 52 changes to increase the voltage at the output terminal 58 of Amp2 with respect to the positive input 54 (the injected current is compared with the current flowing through transistor M1 20). (This was initially zero), (iii) The output from Amp2 (connected to data line 16) changes the gate voltage of transistor M1 20 (data line 16 is the comparison difference) And (iv) accordingly, the current drawn by transistor M120 through node nc44 increases. The mechanisms (i) to (iv) are repeated until the current drawn through the node nc44 by the transistor M120 is equal to the injected data current Idata64 (the difference is no longer detected in the comparison step (ii)). The current drawn by M1 20 matches the injected current and the two terminals 56, 54 of Amp2 52 are made equal. At this time, the gate voltage of MSsense 36 has returned to the original value. The feedback loop reaches equilibrium and provides the correct value for the pixel current.

The following examples are illustrative and should not be construed as limiting the scope of the claims, unless specifically stated in terms of limitations.
(Example)

  For the purposes of this application, transistor mobility is one device characteristic that defines the amount of current that a transistor of a particular size can supply. In other words, for a given gate voltage, the amount of current that flows is (among other things) a function of its mobility. For example, if the same voltage is applied to the gates of two transistors of the same size and one of the mobility is 20% higher, the transistor with the higher mobility will supply a current that is 20% higher (other factors). Are all the same). Mobility is a function of material properties and device manufacturing, and for display manufacturing technology it can vary across the display area.

For all purposes of this application, the threshold voltage of a transistor is the minimum transistor gate voltage required for current to flow. The threshold voltage is a function of material properties and device manufacturing, and thus the threshold voltage can vary across the display area.
(Example 1)

  Circuit simulations were performed using PSPICE® computer software. PSPICE® is computer software for analog and mixed analog / digital circuit simulation, 14692, Rochester, NY, PO Box 23325, 95134 through EMA Design Automation, Inc., San Jose, CA Provided by ORCAD at 2655 Sealy Avenue. PSPICE® software can accept user-created circuit diagrams and transistor models and addressing information and generate simulated responses.

  The circuit diagram simulated by PSPICE® is essentially consistent with the circuits of FIGS. The signals shown in FIG. 4 are control signals that drive different switches in the display driver, and in particular are voltage signals for controlling MS1, MS2 and transistor M2 in the pixel being programmed. The output graph of FIG. 5 represents the current through the programmed pixel as a function of time, while simultaneously representing the data current (Idata 64 sent to the display driver node nc) as a function of time.

  Simulated system variables include the following: (1) The total column current, which is the sum of all pixel currents in a given column, was varied from 150 μA to 3500 μA, (2) the pixel data current was varied from 0.3 μA to 20 μA, (3 ) Pixel transistor M1 was resized to emulate a mobility change of up to 25%. (4) The pixel transistor threshold voltage would simulate a change of up to 50% of the threshold voltage. The voltage source was connected to the gate of M1.

  The plot of FIG. 5 shows how the pixel current matches the data current. This simulation was performed under several system conditions to show that the display driver performs the required operation over a range of conditions.

FIG. 5 shows that the proposed display driver programs the desired level of current for the intended pixel in all of the system variables mentioned above. Simulation results demonstrate that the circuit can perform pixel addressing with the current mismatch correction as intended at the required operating speed and current requirements.
(Example 2)

  The following example was set up to compare the programming of data current in a display pixel that includes a drive transistor M1 with different properties and to demonstrate this functionality at different column current levels.

  The display driver for the display column was fabricated in a single crystal silicon integrated circuit (IC). The column contains test pixel circuits incorporated in the same IC. The test pixel circuit was made to have the same characteristics except for the size of the M1 transistor. The two pixels were made with a difference that the width of M1 was 20% different so as to emulate a 20% mobility difference. An external v voltage source was connected to the pixel to emulate threshold voltage changes. This voltage source represents a 25% change in the threshold of transistor M1.

  In this process, LabVIEW® computer software was used to provide the circuit voltage. LabVIEW® computer software is used to control and emulate scientific and engineering instruments and instrument systems and to perform instrument functions. In the first procedure, a voltage level was established on the program line of each of the two pixels. This was then converted to a current by M1. In order to demonstrate the performance, the conditions were changed as follows. (1) Total column current was varied from 150 μA to 3000 μA, (2) Pixel data current was varied from 0.5 μA to 15 μA, (3) Mobility of pixel transistor M1 was to change size (4) The threshold voltage of the pixel transistor M1 was changed to 25% by introducing a voltage source.

  FIG. 6 shows the current through two pixels (Pix1 and Pix2) when programmed in a typical conventional manner. FIG. 6 shows the threshold voltage (Pix1) increased by 25% and the mobility (Pix2) increased by 20%. For example, at low data levels, Pix1 supplied approximately 2.5 μA. However, at the same data level, Pix2 supplied approximately 4 μA. This difference appears as a difference in display brightness, even though both pixels intend to have the same intensity level (as intended at the same data level).

  The plot of FIG. 7 shows the normalized rate of change between two pixels as a function of data voltage.

  6 and 7 show the degree of current change due to the change in the M1 characteristic.

  FIG. 8 shows the current through two identical pixels programmed with the display driver of FIG. FIG. 8 shows that the two currents perfectly match even though the transistor M1 has changing characteristics. The normalized percentage plot in FIG. 9 shows only the measurement tolerance variation between the two pixel currents.

  Experimental data demonstrate that non-uniformity has been reduced from 70% to less than 3% for two pixels, standard drive and inventive driver control, respectively. This level of non-uniformity is improved to an order of magnitude over the entire data range. In addition, simulations have demonstrated that programming time can be reduced below that required by typical prior art current copy pixels.

  The inventive data driver can be built into a standard IC or into the same panel as the active backplane. Polycrystalline silicon TFTs provide a good compromise between performance and cost for the proposed driver.

  The inventive circuit reduces the complexity of the active matrix backplane by providing a level of uniformity with a lower complexity than that of typical prior art modification techniques for a two-transistor TFT pixel. In addition, the performance requirements for the transistors on the backplane are reduced, so lower cost technology can be used for large area arrays.

  While preferred embodiments of the invention have been described, the invention is susceptible to variations and modifications and should therefore not be limited to the exact details of the examples. The invention encompasses changes and modifications that fall within the scope of the following claims.

Claims (10)

A display,
A plurality of pixels, each of which is operatively connected to a data line, a select line and a current line , wherein each of the plurality of pixels light-emitting diode, the capacitor and two thin film transistors, i.e., an address transistor and the driving transistor has each of the transistors is three terminals, namely a source, a drain, and a gate,
Here, one of the drain or source of the address transistor is connected to the data line, the other is connected to the gate of the driving transistor, and one of the drain or source of the driving transistor is connected to the light emitting diode. And the gate of the address transistor is connected to a select line, and one pixel is addressed when the select line is maintained at a voltage that activates the address transistor in the one pixel;
A circuit external to the plurality of pixels, wherein the driving of the addressed pixel supplied from the current line by adjusting the voltage value of the data line until the current value is set to a required value. A circuit configured to dynamically control a current value flowing through a transistor , wherein each of the required pixel currents is set by an external data signal independent of other pixel current values;
Including
Circuits external to the plurality of pixels may include the address of the addressed pixel within a time period equal to or less than a time period during which the select line is held at a voltage value that activates the address transistor of the addressed pixel. Set the required current value in the drive transistor,
Thereby, the external circuit of the plurality of pixels does not store or process the external data signal values of other pixels in order to set the required current value in the drive transistor of the addressed pixel,
A circuit external to the plurality of pixels sets a required current value in the drive transistor of the addressed pixel, while the current line is turned on by the other connected to the same current line. A display characterized by supplying current to a pixel at the same time .
The display according to claim 1,
Circuitry external to the plurality of pixels is connected to the data line and the current line;
The plurality of pixels are connected to both the same data line and the same current line, and at least one of the addresses that sets a desired pixel current value for the addressed pixel in response to the data line Included pixels ,
An external circuit of the plurality of pixels, by sampling a current value of the current line, detects a current value drawn by the addressed pixel, the current value drawn by the addressed pixel from the outside When the data line voltage value is controlled according to the difference compared with the set data current value, and the current value drawn by the addressed pixel is compared with the externally set data current value And the loop back circuit operation is repeated until no difference is detected.
The display according to claim 1,
Circuitry external to the plurality of pixels has a plurality of loopback circuits each connected to the data line and the current line;
The plurality of pixels connected to both the same data line and the same current line are at least one of the addressed to set a required pixel current value to the addressed pixel in response to the data line voltage. It comprises pixels,
For each loopback circuit connected to the same current line as the same data line of the plurality of pixels, the loopback circuit causes the data line to draw a desired current value from the current line. the voltage value of each connected pixel to sequentially control, set,
The loopback circuit determines each pixel current value and the column data line voltage to program the adjusted pixel voltage value until the adjusted pixel current value matches an external reference current value. Configured to adjust the value ,
Said display.
The display according to claim 3 ,
At least one of the loopback circuits samples a current value of the current line, detects a current value drawn by a driving transistor of an addressed pixel, and compares the current value with an externally set data current value and, wherein the adjusting the column data line voltage value is the address value of the current drawn by the drive transistor of an addressed pixel from the current line to change the current value drawn by the drive transistor in accordance with the difference The display is characterized in that the loop back circuit operation is repeated until no difference is detected when compared with the externally set data current value for the pixel .
The display according to claim 3 ,
Wherein at least one loop-back circuit further reference current value of the pixels stored as the value of the current drawn to the activities at the current drawn by the drive transistor of the address from the connected current lines to the Pixel a comparator for comparing the bets, including an adjuster for adjusting the voltage value of the column data lines according to a comparison between the voltage value associated with the reference current value,
Said display.
The display according to claim 3 ,
The at least one loopback circuit comprises:
A current source;
And a detection module having an amplifier having an input terminal connected to a constant voltage source, an input terminal connected to the source transistor, and an output terminal connected to the gate of the source transistor and the detection transistor so as to be switched to the input terminal. And
When the switch is ON, the amplifier operates the source transistor to sample the column current value, and when the switch is OFF, the amplifier according to the difference between the current value of the detection transistor and the reference data current value set from the outside. The display characterized by adjusting a voltage value of the detection transistor.
The display according to claim 3 ,
The at least one loopback circuit includes an amplifier connected between a detection transistor and a stored pixel current value, and the column data is responsive to a difference between the detection transistor voltage value and the stored pixel current value. Said display comprising a data programming module for adjusting the line voltage value;
4. The display of claim 3 , wherein the at least one loopback circuit is
A current source;
A detection module having an amplifier having an input terminal connected to a constant voltage source, an input terminal connected to a source transistor, and an output terminal connected to the gate of a switchable source transistor or detection transistor; When the switch is ON, the amplifier activates the source transistor to sample the column current value. When the switch is OFF, the amplifier responds to the difference between the current value of the detection transistor and the reference data current value set from the outside. To adjust the voltage value of the detection transistor,
An amplifier having an amplifier connected between the detection transistor and a stored pixel current value and adjusting the column data line voltage in response to a difference between the detection transistor voltage value and the stored pixel current value And said data programming module.
4. The display of claim 3 , wherein the at least one loopback circuit is
A current source;
A detection module having an amplifier having an input terminal connected to a constant voltage source, an input terminal connected to a source transistor, and an output terminal connected to the gate of a switchable source transistor or detection transistor; When the switch is ON, the amplifier activates the source transistor to sample the column current value, and when the switch is OFF, the difference between the current value of the detection transistor and the current value drawn by the load of the column current line In response, adjust the voltage value of the detection transistor,
An amplifier connected between the source transistor and the detection transistor for adjusting a column data line voltage value in response to a difference between a voltage value of the detection transistor and a voltage value related to a stored pixel current value; said display, characterized in that it comprises a data programming module having.
A display,
And data lines, each one of the plurality of pixels, said plurality of pixels are connected to the select line and the current line,
Here, each pixel has a light emitting diode, a capacitor, and two pixel transistors, a first pixel transistor and a second pixel transistor, each transistor having a source, a drain, and a gate,
Here, one of the drain or source of the first pixel transistor is connected to the data line, the other is connected to the gate of the second pixel transistor, and the drain or source of the second pixel transistor is connected. One is connected to the light emitting diode, and the gate of the first pixel transistor is connected to the selection line, and one pixel activates the first pixel transistor in the pixel to which the selection line is addressed. Addressed when kept at voltage,
An external circuit of a plurality of pixels, as required current value is set so as to be drawn from the current line connected to the pixel by the second pixel transistors, said to be connected to the pixels A circuit configured to dynamically control a current value drawn by the second pixel transistor in the addressed pixel from a current line connected to the pixel by adjusting a voltage value of the data line;
Here, each required pixel current is set by an external data signal independent of other pixel current values,
Including
An external circuit of the plurality of pixels is the address in the selected line is the addressed shorter than or equal to the period to be held at a voltage value to start the first pixel transistor in the pixel the second pixel transistors of the pixel draw sets the required value of the current,
Thereby, the external circuit of the plurality of pixels stores the external data signal values of other pixels in order to dynamically control and set the required value of the current drawn by the drive transistor of the addressed pixel. Or do not process
A circuit external to the plurality of pixels sets a current value drawn from the current line by the second pixel transistor of the addressed pixel, while the current lines are simultaneously connected to the same current line. Said display, characterized in that it supplies current to other lit pixels.

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