A light-emitting element compensation circuit, a driving circuit and an LED display device

Abstract

The present invention provides a light-emitting element compensation circuit, a driving circuit, and an LED display device. In the compensation circuit, a first compensation switch device is provided between a first pixel unit and a second pixel unit, and a second compensation switch device is provided between the second pixel unit and a third pixel unit. When the first switch device is turned on, the first pixel unit is electrically connected to the second pixel unit and provides a compensation current to the second pixel unit; when the second switch device is turned on, the third pixel unit is electrically connected to the second pixel unit and provides a compensation current to the second pixel unit. Through the above-mentioned compensation circuit, it is possible to ensure that the second pixel unit has a larger operating current range and emits a higher luminous intensity. When the compensation switch element is turned on, the variable resistors (i.e., switch elements) between the pixel units are connected in parallel, thereby reducing the effective resistance value of the pixel unit, thereby reducing the power consumption of the switch element.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor device display, and particularly to a light-emitting element compensation circuit, a driving circuit and an LED display device. Background Art

[0002] Both the LCD / OLED display backplane and the current Micro LED element display panel adopt thin-film TFT elements as switching devices to change the voltage / current of the light-emitting devices, control the light-emitting intensity of the light-emitting devices, form the three primary colors of light sources visible to the human eye, and then compose different colors of light and images of various display screens. The TFT element determines the value of the input current by adjusting the size of the channel for electron flow in the semiconductor material within the TFT. When the light-emitting element is connected in series with the TFT element, the magnitude of the input current of the light-emitting element can be defined by the TFT element.

[0003] In Micro LED elements, the starting voltages of RGB chips are usually VR < VB = VG, that is, the starting voltage of the R chip is less than the starting voltages of the B and G chips. When the R, G, and B chips are electrically connected in parallel, when an external voltage / current is applied, the current will only pass through the R chip, causing the R chip to light up, while the B and G chips are in a state where they cannot be driven and thus cannot light up. Summary of the Invention

[0004] In view of the defects in the driving of LED chips in the prior art, the present invention provides a light-emitting element compensation circuit, a driving circuit and an LED display device. In the compensation circuit of the present invention, a first compensation switching device is provided between the first pixel unit and the second pixel unit, and a second compensation switching device is provided between the second pixel unit and the third pixel unit. When the first switching device is turned on, the first pixel unit and the second pixel unit are electrically connected to provide a compensation current to the second pixel unit; when the second switching device is turned on, the third pixel unit and the second pixel unit are electrically connected to provide a compensation current to the second pixel unit. Through the above compensation circuit, it is possible to ensure that the second pixel unit has a larger current range and emits a higher light-emitting intensity. And it can reduce the effective resistance value of the pixel unit, thereby reducing the power consumption of the switching element.

[0005] According to an embodiment of the present invention, a light-emitting element compensation circuit is provided, and the light-emitting element compensation circuit includes:

[0006] A first pixel unit, a second pixel unit and a third pixel unit;

[0007] A first compensation switching device, provided between the first pixel unit and the second pixel unit, and when the first switching device is turned on, electrically connecting the first pixel unit and the second pixel unit;

[0008] The second compensation switch device is disposed between the second pixel unit and the third pixel unit. When the second switch device is turned on, the third pixel unit is electrically connected to the second pixel unit.

[0009] Optionally, the first pixel unit includes a first light-emitting element and a first switch element connected in series, the second pixel unit includes a second light-emitting element and a second switch element connected in series, and the third pixel unit includes a third light-emitting element and a third switch element connected in series.

[0010] Optionally, one end of the first compensation switching device is connected between the first light-emitting element and the first switching element, and the other end is connected between the second light-emitting element and the second switching element.

[0011] Optionally, one end of the second compensation switching device is connected between the second light-emitting element and the second switching element, and the other end is connected between the third light-emitting element and the third switching element.

[0012] Optionally, the light emitting element compensation circuit further includes a timing control circuit, and the timing control circuit controls the first compensation switch device and the second compensation switch device to turn on or off.

[0013] Optionally, the timing control circuit controls the on or off of the first compensation switch element and the second switch element in a pulse width modulation mode.

[0014] Optionally, when the second pixel unit needs to be lit, the timing control circuit controls the first compensation switch element and the second compensation switch element to be turned on alternately to provide a compensation current to the second pixel unit.

[0015] Optionally, the first compensation switching device and the second compensation switching device are TFT elements.

[0016] According to another embodiment of the present invention, there is provided a light emitting element driving circuit, comprising:

[0017] A driving chip, used to drive the light-emitting element to emit light; and

[0018] The compensation circuit is the compensation circuit described in the present invention.

[0019] Optionally, the timing control circuit of the compensation circuit is connected to the driving chip and the first compensation switch device and the second compensation switch device of the compensation circuit.

[0020] According to another embodiment of the present invention, an LED display device is provided, comprising: a circuit substrate and a light-emitting element arranged on the circuit substrate, wherein a driving circuit is arranged on the circuit substrate, and the driving circuit is the light-emitting element driving circuit described in the present invention.

[0021] Optionally, the LED display device further includes a power supply module, which is connected to the driving circuit to supply power to a driving chip and a compensation circuit in the driving circuit.

[0022] As described above, the light emitting element compensation circuit, driving circuit, and LED display device of the present invention have the following beneficial effects:

[0023] In the compensation circuit provided by the present invention, a first compensation switch device is provided between the first pixel unit and the second pixel unit, and a second compensation switch device is provided between the second pixel unit and the third pixel unit. When the first switch device is turned on, the first pixel unit is electrically connected to the second pixel unit and provides a compensation current to the second pixel unit; when the second switch device is turned on, the third pixel unit is electrically connected to the second pixel unit and provides a compensation current to the second pixel unit. The above-mentioned compensation circuit can ensure that the second pixel unit has a larger operating current range and emits a higher luminous intensity. The driving circuit with this compensation circuit can ensure that the light-emitting element emits stable light and has a better luminous effect.

[0024] When the first compensation switch is on, the variable resistors (i.e., switches) of the first and second pixel units are connected in parallel. When the second compensation switch is on, the variable resistors (i.e., switches) of the second and third pixel units are connected in parallel. This reduces the effective resistance of the pixel units and reduces power consumption of the switches.

[0025] The display device driving circuit of the present invention includes the compensation circuit described above, which enables the light-emitting element to emit light stably and with higher light intensity, thereby improving the display effect of the display device. Furthermore, since the compensation circuit can reduce the power consumption of the switching element, the power consumption of the entire display device can also be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Shown is a schematic structural diagram of a pixel unit in a display module in the prior art.

[0027] Figure 2 Shown is a schematic diagram of an equivalent circuit of a pixel unit in a light-emitting element compensation circuit provided in the first embodiment of the present invention.

[0028] Figure 3 Shown is a schematic diagram of a light-emitting element compensation circuit provided in the first embodiment of the present invention.

[0029] Figure 4 Shown is a schematic diagram of a current pulse applied to a pixel cell.

[0030] Figure 5 Shown is a schematic diagram of a driving circuit provided in the second embodiment.

[0031] Figure 6 Shown is a structural schematic diagram of the LED display device provided in Example 3.

[0032] Component number description

[0033] 001 Switching element 102-2 Second light-emitting element

[0034] 100 pixel unit 102-3 second compensation switch device

[0035] 100-1 variable resistor 103 third pixel unit

[0036] 100-2 Fixed resistor 103-1 Third switch element

[0037] 101 first pixel unit 103-2 third light emitting element

[0038] 101-1 First switching element 103-3 Third compensation switching device

[0039] 101-2 First light emitting element 104 First current pulse

[0040] 101-3 First compensation switch device 204 Second current pulse

[0041] 102 Second pixel unit 304 Third current pulse

[0042] 102-1 Second switch element 205 Compensation current

[0043] 400 Display device 403 Light-emitting element

[0044] 401 mask 404 bottom shell

[0045] 402 circuit board DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0047] In a Micro LED display panel, the TFT element is connected in series with the light-emitting element as a switching element, and the magnitude of the input current of the light-emitting element can be defined by the TFT element. As Figure 1 shown, generally speaking, the electron flow channel of the switching element 001 can be adjusted by the voltages Vgate, Vdata, and Vcomplementrary input to the TFT element, and V DD is a two-terminal voltage with a variable voltage value input from the outside to the TFT element. In a Micro LED element, the starting voltages of the RGB chips are usually VR < VB = VG, that is, the starting voltage of the R (red) chip is less than that of the B (blue) chip and the G (green) chip. When the R, G, and B chips are electrically connected in parallel, when a voltage / current is applied from the outside, the current will only pass through the R chip, causing the R chip to light up, while the B and G chips are in a state where they cannot be driven and cannot light up. Therefore, within the same adjustable current range of the switching element, there will be a problem of insufficient brightness of the red light chip. At the same time, in the series-connected current, the resistance value of individual switching elements is relatively large, resulting in an increase in the power consumption of the device.

[0048] Embodiment 1

[0049] In view of the above defects in the prior art, this embodiment provides a light-emitting element compensation circuit. In basic circuit theory, the element composed of the TFT element can be assumed to be a variable resistor. For a light-emitting element, such as a light-emitting element with fast time-domain response of a Micro LED chip, when a current / voltage is applied to the Micro LED chip, the Micro LED chip can be regarded as an element similar to a fixed resistor. Accordingly, as Figure 2 shown, the light-emitting element and the switching element connected in series in the display device can be regarded as a variable resistor 100-1 and a fixed resistor 100-串联。一个发光元件与一个可变电阻即形成一个显示屏上的像素单元100。每个发光器件只能借由一组开关元件来提供电流,使得发光元件的发光强度与开关元件提供的电流强度相关。

[0050] 如 Figure 3In this embodiment, the light-emitting element compensation circuit includes a first pixel unit 101, a second pixel unit 102, and a third pixel unit 103, as well as a first compensation switch device 101-3 and a second compensation switch device 102-3. The first pixel unit 101 includes a first switch element 101-1 and a first light-emitting element 101-2 connected in series, the second pixel unit 102 includes a second switch element 102-1 and a second light-emitting element 102-2 connected in series, and the third pixel unit 103 includes a third switch element 103-1 and a third light-emitting element 103-2 connected in series. The first switch element 101-1, the second switch element 102-1, and the third switch element 103-1 are TFT elements. The first light-emitting element 101-2, the second light-emitting element 102-2, and the third light-emitting element 103-2 are all LED chips, preferably Micro LED chips. In an optional embodiment, the first light-emitting element 101 - 2 is a green LED chip, the second light-emitting element 102 - 2 is a red LED chip, and the third light-emitting element 103 - 2 is a blue LED chip.

[0051] Also refer to Figure 3 The first compensation switch device 101-3 is disposed between the first pixel unit 101 and the second pixel unit 102. Specifically, one end of the first compensation switch device 101-3 is connected between the first switching element 101-1 and the first light-emitting element 101-2 of the first pixel unit 101, and the other end of the first compensation switch device 101-3 is connected between the second switching element 102-1 and the second light-emitting element 102-2 of the second pixel unit 102. When the first compensation switch device 101-3 is turned on, the first pixel unit 101 and the second pixel unit 102 are electrically connected. At this time, when current / voltage is supplied to the pixel units, the first pixel unit 101 can supply current to the second pixel unit 102 via the first compensation switch device 101-3, causing the second light-emitting element 102-2 of the second pixel unit 102 to have a higher luminous intensity and a brighter brightness.

[0052] Also refer to Figure 3The second compensation switch device 102-3 is disposed between the second pixel unit 102 and the third pixel unit 103. Specifically, one end of the second compensation switch device 102-3 is connected between the second switching element 102-1 and the second light-emitting element 102-2 of the second pixel unit 102, and the other end of the second compensation switch device 102-3 is connected between the third switching element 103-1 and the third light-emitting element 103-2 of the third pixel unit 103. When the second compensation switch device 102-3 is turned on, the second pixel unit 102 and the third pixel unit 103 are electrically connected. At this time, when current / voltage is supplied to the pixel unit, the third pixel unit 103 can supply current to the second pixel unit 102 via the second compensation switch device 102-3, resulting in a higher luminous intensity and brightness for the second light-emitting element 102-2 of the second pixel unit 102. When the first compensation switch device 101-3 and the second compensation switch device 102-3 are turned off, the second pixel unit 102 displays normally at the original current / voltage.

[0053] As described above, by providing the first compensation switch device and the second compensation switch device, the light emitting element of the second pixel unit can have a larger operating current range, so that it can emit higher luminous intensity and emit light of different intensities, especially in the current compensation device, which can emit brighter brightness. In addition, if Figure 3 As shown, when the first compensation switching device and / or the second compensation switching device is turned on, the variable resistors of the first pixel and the second pixel (i.e., the first switching element and the second switching element) are connected in parallel, or the variable resistors of the second pixel and the third pixel (i.e., the second switching element and the third switching element) are connected in parallel. The parallel connection of the resistors reduces the effective resistance value of the pixel unit, thereby reducing the power consumption of the switching element during the period when the compensation switching device is turned on.

[0054] In an optional embodiment, the compensation circuit further includes a timing control circuit, which controls the on and off timing of the first compensation switch device and the second compensation switch device according to a certain timing control mode. Optionally, the timing control circuit controls the on and off timing of the first compensation switch device and the second compensation switch device in a pulse width modulation mode. Figure 4, shows the current pulses applied to different pixel units in an optional embodiment of this embodiment. The first current pulse 104 is a current pulse applied to the first pixel unit 101, the second current pulse 204 is a current pulse applied to the second pixel unit 102, and the third current pulse 304 is a current pulse of the third pixel unit 103. During the time periods T1 and T2, the second compensation switch element 102-3 is turned on, and at this time the third current pulse 304 provides a compensation current to the second pixel unit 102; during the time periods T3 and T4, the first compensation switch element 101-3 is turned on, and at this time the first current pulse 104 provides a compensation current to the second pixel unit 102. Finally, the second pixel unit 102 obtains Figure 4 The compensation current 205 is superimposed on the second current pulse, so that the second light-emitting element 102-2 of the second pixel unit 102 has a stronger current intensity during the time periods T1, T2, T3 and T4, and thus can have a stronger luminous intensity and brighter brightness.

[0055] Example 2

[0056] This embodiment provides a light emitting element driving circuit, which includes a driving chip and a compensation circuit. Figure 5 As shown, the timing control circuit of the compensation circuit is connected to the driver chip and the first compensation switch device and the second compensation switch device of the compensation circuit to realize the connection between the compensation circuit and the driver chip. When current / voltage is applied to the pixel unit, the driver chip receives the signal and drives the light-emitting element in the pixel unit to emit light. The timing control circuit is based on Figure 4 The timing mode shown controls the opening and closing of the first compensation switch device and the second compensation switch device, thereby achieving current compensation for the second pixel unit, so that the second pixel unit emits stronger light.

[0057] In the driver circuit of this embodiment, the same control voltage is applied to the control terminals of the first, second, and third switching elements. For example, the control terminals of the first, second, and third switching elements are connected together, and controlled by a sensing control line SG. Each pixel unit is connected to a driver chip, which is configured to drive the light-emitting element to emit light based on a data voltage. Taking the first, second, and third pixel units described above as an example, the first pixel unit includes a first driver chip connected to the first light-emitting element; the second pixel unit includes a second driver chip connected to the second light-emitting element; and the third pixel unit includes a third driver chip connected to the third light-emitting element. Furthermore, the first switching element is connected in series with the output terminals of the first and second driver chips, while the second switching element is connected in series with the output terminals of the second and third driver chips. The output terminal of the third driver chip is connected to the sensing line SL of the driver circuit via the third switching element. The first, second, and third driver chips are connected to a data line DL and generate a driving current based on the data voltage on the data line, driving the first, second, and third light-emitting elements to emit light. The sensing line SL is used to sense the output of the driver chip and obtain the driving current value based on the change in the voltage on the sensing line within a predetermined time. The timing control circuit in the compensation circuit obtains the value of the driving current and controls the opening and closing of the first compensation switching device and the second compensation switching device in a pulse width control mode according to the determined current value.

[0058] Also combined Figure 4 In the time period T1 to T4, it is detected that the current flowing through the second pixel unit is small, and the second pixel unit needs to be current compensated. In the time period T1 and T2, the timing control circuit controls the second compensation switch element 102-3 to turn on, and the third current pulse 304 provides a compensation current to the second pixel unit 102, so that the brightness of the second light-emitting element 102-2 is improved; in the time period T3 and T4, the first compensation switch element 101-3 is turned on, and the first current pulse 104 provides a compensation current to the second pixel unit 102, so that the brightness of the second light-emitting element 102-2 is improved. Finally, the second pixel unit 102 obtains Figure 4 The compensation current 205 shown is superimposed on the second current pulse, so that the second light-emitting element 102-2 of the second pixel unit 102 has a stronger current intensity during time periods T1, T2, T3, and T4, thereby achieving a stronger luminous intensity and brighter brightness. The second light-emitting element also has a wider current adjustment range, which can meet different brightness requirements.

[0059] Example 3

[0060] This embodiment provides an LED display device, such as Figure 6As shown, the display device 400 includes a face mask 401 and a bottom housing 404. The face mask 401 and the bottom housing 404 can be fixed to each other using buckles, positioning bolts, and positioning holes, so as to form a cavity between the face mask 401 and the bottom housing 404. The cavity can accommodate a circuit board 402 and a light-emitting element 403 located above the circuit board.

[0061] In the display device 400, the light-emitting elements may include light-emitting elements capable of emitting light of different colors. For example, they may include the green LED chip as the first light-emitting element 101-2, the red LED chip as the second light-emitting element 102-2, and the blue LED chip as the third light-emitting element 103-2, as described in Example 1. A circuit layer is provided within the circuit board 402, which may be a TFT substrate or a PCB substrate. For example, the TFT substrate includes a switching element connected in series with each light-emitting element. One switching element and one light-emitting element constitute a pixel unit of the display device 400. The TFT substrate also includes a first compensation switching device connected between the first pixel unit and the second pixel unit, and a second compensation switching device connected between the second pixel unit and the third pixel unit. The TFT substrate also includes a circuit layer connecting the pixel units and the first and second compensation switching devices. This circuit layer connects the pixel units and the first and second compensation switching devices to external voltage / current. The display device is also provided with a power module, to which the above-mentioned circuit layer is connected. At the same time, the power module has a terminal that can be connected to an external power source, and the electrical connection between the circuit board's circuit layer and the external power source is achieved through the power module.

[0062] In addition, the circuit board 402 also includes a driver chip arranged thereon, and the driver chip is connected to the pixel unit to drive the light-emitting element in the pixel unit to emit light. Correspondingly, the circuit layer of the circuit board also includes a driving circuit connected to the driver chip, and the driving circuit realizes the connection between the driver chip and the external driving signal. In addition, the circuit layer of the circuit board 402 also includes a timing control circuit, and the timing control circuit connects the driver chip and the first compensation switch device and the second compensation switch device of the compensation circuit to realize the connection between the compensation circuit and the driver chip. When current / voltage is applied to the pixel unit, the driver chip receives a signal and drives the light-emitting element in the pixel unit to emit light. The timing control circuit is based on Figure 4 The timing mode shown controls the opening and closing of the first compensation switching device and the second compensation switching device, thereby performing current compensation on the second pixel unit during the compensation period, so that the second pixel unit emits stronger light.

[0063] As described above, the display device of this embodiment includes the compensation circuit and driving circuit described in Example 1 and Example 2, so that the red light LED chip therein has a larger operating current space and can emit brightness of different intensities as needed to meet different display requirements and achieve better display effects.

[0064] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A light emitting element compensation circuit, characterized in that: include: a first pixel unit, a second pixel unit, and a third pixel unit; a first compensation switch device, disposed between the first pixel unit and the second pixel unit, and electrically connecting the first pixel unit and the second pixel unit when the first compensation switch device is turned on; A second compensation switching device is arranged between the second pixel unit and the third pixel unit. When the second compensation switching device is turned on, the third pixel unit is electrically connected to the second pixel unit. The first compensation switching device and the second compensation switching device are alternately turned on. When the second pixel unit needs to be lit, the first compensation switching device and the second compensation switching device are controlled to be alternately turned on to provide a compensation current to the second pixel unit.

2. The compensation circuit according to claim 1, wherein: The first pixel unit includes a first light-emitting element and a first switch element connected in series, the second pixel unit includes a second light-emitting element and a second switch element connected in series, and the third pixel unit includes a third light-emitting element and a third switch element connected in series.

3. The compensation circuit according to claim 2, wherein: One end of the first compensation switching device is connected between the first light emitting element and the first switching element, and the other end is connected between the second light emitting element and the second switching element.

4. The compensation circuit according to claim 2, wherein: One end of the second compensation switching device is connected between the second light emitting element and the second switching element, and the other end is connected between the third light emitting element and the third switching element.

5. The compensation circuit according to claim 1, wherein: It also includes a timing control circuit, which controls the first compensation switching device and the second compensation switching device to turn on or off.

6. The compensation circuit according to claim 5, characterized in that: The timing control circuit controls the turning on or off of the first compensation switching device and the second compensation switching device in a pulse width modulation mode.

7. The compensation circuit according to claim 1, wherein: The first compensation switching device and the second compensation switching device are TFT elements.

8. A light emitting element driving circuit, characterized in that: include: A driver chip, used for driving the light-emitting element to emit light; as well as The compensation circuit is the compensation circuit according to any one of claims 1 to 7.

9. The light emitting element driving circuit according to claim 8, wherein: The timing control circuit of the compensation circuit is connected to the driving chip and the first compensation switch device and the second compensation switch device of the compensation circuit.

10. An LED display device, characterized in that: include: A circuit substrate and a light-emitting element provided on the circuit substrate, wherein a driving circuit is provided on the circuit substrate, and the driving circuit is the light-emitting element driving circuit according to claim 8 or 9.

11. The LED display device according to claim 10, characterized in that: It also includes a power supply module, which is connected to the driving circuit to supply power to the driving chip and the compensation circuit in the driving circuit.

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