Pixel driving circuit, method and display panel

Abstract

The application discloses a pixel driving circuit, a method and a display panel. The pixel driving circuit comprises a light emitting unit, a first transistor, a second transistor, a driving transistor and a bistable flip-flop. The drain of the first transistor, the source of the second transistor and the gate of the driving transistor are all connected with the bistable flip-flop. The source of the driving transistor is connected with a first voltage, and the drain is connected with the light emitting unit. The bistable flip-flop is also connected with a second voltage, and the second voltage is loaded to the driving transistor based on a light emitting data signal when the first transistor is turned on, so that the driving transistor generates a driving current and drives the light emitting unit to emit light. The first voltage and the second voltage both correspond to the color of the light emitting unit. The application can separately process the gray scale and the color of the display. The light emitting units of different colors provide the driving current corresponding to the color, so that all the gray scales of various colors can be displayed, and the white balance can also be considered, which can greatly improve the color display effect.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a pixel driving circuit, method and display panel. Background Art

[0002] Currently, digital drive is the main method used to drive monochrome array displays of light-emitting diodes (LEDs). This involves dividing the scanning time of each display frame into subfields of varying sizes. Each subfield is then individually controlled for light emission, and the combined light emission durations of the subfields are combined to control the total light emission duration within the frame. This controls the lighting duration of each light-emitting unit in the display panel, achieving the effect of different grayscales for each light-emitting unit.

[0003] In a full-color array of light-emitting diodes, white light (W) is generated by summing the three primary colors of red (R), green (G), and blue (B). To achieve full-color RGB display, if the existing digital drive method is used, that is, the drive current of each color pixel remains unchanged and only the light-emitting duration of each color pixel is controlled separately, the number of grayscale levels of red and blue pixels will be small, or white balance will not be achieved, thus failing to achieve a good color display effect. Summary of the Invention

[0004] The embodiments of the present application provide a pixel driving circuit, method and display panel to solve the technical problem that the existing driving method cannot achieve a good color display effect.

[0005] In order to solve the above technical problems, the embodiments of the present application disclose the following technical solutions:

[0006] In a first aspect, a pixel driving circuit is provided, which is applied to a display panel and includes:

[0007] Light-emitting unit;

[0008] a first transistor, wherein a source of the first transistor is connected to a light emitting data signal, a gate of the first transistor is connected to a row scanning signal, and a drain of the first transistor is electrically connected to a bistable trigger;

[0009] a second transistor, wherein a source of the second transistor is electrically connected to the bistable trigger, a gate of the second transistor is connected to a row clear signal, and a drain of the second transistor is electrically connected to a drain of the first transistor;

[0010] a driving transistor; a gate of the driving transistor being electrically connected to the bistable trigger, a source of the driving transistor being connected to a first voltage, and a drain of the driving transistor being electrically connected to the anode of the light-emitting unit;

[0011] In which, the bistable trigger is also connected to a second voltage, and based on the row scan signal and the light-emitting data signal, when the second voltage is loaded to the gate of the driving transistor, the driving transistor generates a driving current according to the first voltage and the second voltage and drives the light-emitting unit to emit light, and the first voltage and the second voltage both correspond to the color of the light-emitting unit.

[0012] In combination with the first aspect, the color of the light emitting unit is any one of red, green and blue;

[0013] The driving current generated by the driving transistor connected to the red light-emitting unit, the driving current generated by the driving transistor connected to the green light-emitting unit, and the driving current generated by the driving transistor connected to the blue light-emitting unit have a ratio of a:b:c, satisfying: a:b:c is equal to the ratio between the red luminous flux, green luminous flux and blue luminous flux corresponding to white light under the color coordinates corresponding to the display panel.

[0014] In combination with the first aspect, the bistable trigger includes a third transistor, a fourth transistor, a fifth transistor and a sixth transistor;

[0015] The source of the third transistor and the source of the fifth transistor are both electrically connected to a first input port, the first input port is connected to a third voltage, the drain of the third transistor and the drain of the fourth transistor are both electrically connected to the drain of the first transistor, the gate of the third transistor is electrically connected to the gate of the fourth transistor, a first node is provided on a connection line between the gate of the third transistor and the gate of the fourth transistor, the source of the fourth transistor and the source of the sixth transistor are both electrically connected to a second input port, the second input port is connected to the second voltage, and the source of the fourth transistor is also electrically connected to the source of the second transistor;

[0016] The gate of the fifth transistor and the gate of the sixth transistor are both electrically connected to the drain of the first transistor, the drain of the fifth transistor is electrically connected to the drain of the sixth transistor, a second node is provided on the connecting line between the drain of the fifth transistor and the drain of the sixth transistor, the first node is electrically connected to the second node, the second node is electrically connected to the output port, and the output port is electrically connected to the gate of the driving transistor.

[0017] In combination with the first aspect, the third transistor, the fifth transistor and the driving transistor are P-type transistors, and the first transistor, the second transistor, the fourth transistor and the sixth transistor are N-type transistors.

[0018] In combination with the first aspect, the source of the driving transistor is electrically connected to a third input port, the third input port is configured to be electrically connected to a first power supply module via a first signal line, and the first power supply module is configured to provide the first voltage corresponding to the color of the light-emitting unit;

[0019] The second input port is configured to be electrically connected to a second power supply module via a second signal line, and the second power supply module is configured to provide the second voltage corresponding to the color of the light-emitting unit;

[0020] In which, the first signal line corresponding to the red light-emitting unit, the first signal line corresponding to the green light-emitting unit, and the first signal line corresponding to the blue light-emitting unit are arranged in different layers of the display panel; and / or, the second signal line corresponding to the red light-emitting unit, the second signal line corresponding to the green light-emitting unit, and the second signal line corresponding to the blue light-emitting unit are arranged in different layers of the display panel.

[0021] In combination with the first aspect, when the driving transistor operates in a saturation region, the first voltage, the second voltage, and the driving current satisfy the following corresponding relationship:

[0022]

[0023] Among them, I ds is the driving current, μ is the mobility of the driving transistor, C ox is the unit area capacitance of the gate oxide layer of the driving transistor, W is the channel width of the driving transistor, L is the channel length of the driving transistor, V gs is the difference between the first voltage and the second voltage, V h is the threshold voltage of the driving transistor.

[0024] In a second aspect, a pixel driving method is provided for driving the pixel driving circuit according to any one of the first aspects, the method comprising:

[0025] Based on the input row scan signal, the first transistor transmits the received light emitting data signal to the bistable trigger when it is turned on;

[0026] Based on the light-emitting data signal, the bistable trigger applies the received second voltage to the gate of the driving transistor according to a set timing, so as to turn on the driving transistor;

[0027] The driving transistor generates a driving current according to a first voltage received by the source and a second voltage received by the gate, wherein the first voltage and the second voltage both correspond to the color of the light-emitting unit;

[0028] The light emitting unit is driven to emit light based on the driving current and the on-time of the driving transistor.

[0029] In combination with the second aspect, the color of the light emitting unit is any one of red, green and blue;

[0030] The driving current received by the red light-emitting unit, the driving current received by the green light-emitting unit and the driving current received by the blue light-emitting unit have a ratio of a:b:c, satisfying: a:b:c is equal to the ratio between the red luminous flux, green luminous flux and blue luminous flux corresponding to the white light under the color coordinates corresponding to the display panel.

[0031] In combination with the second aspect, when the driving transistor operates in a saturation region, the first voltage, the second voltage, and the driving current satisfy the following corresponding relationship:

[0032]

[0033] Among them, I ds is the driving current, μ is the mobility of the driving transistor, C ox is the unit area capacitance of the gate oxide layer of the driving transistor, W is the channel width of the driving transistor, L is the channel length of the driving transistor, V gs is the difference between the first voltage and the second voltage, V h is the threshold voltage of the driving transistor.

[0034] In a third aspect, a display panel is provided, comprising a pixel driving circuit as described in any one of the first aspects.

[0035] One of the above technical solutions has the following advantages or beneficial effects:

[0036] Compared with the prior art, the present invention provides a pixel driving circuit, comprising a light-emitting unit, a first transistor, a second transistor, a driving transistor, and a bistable trigger. The source of the first transistor is connected to a light-emitting data signal, the gate is connected to a row scan signal, and the drain is connected to the bistable trigger. The source of the second transistor is connected to the bistable trigger, the gate is connected to a row clear signal, the drain is connected to the drain of the first transistor, the gate of the driving transistor is connected to the bistable trigger, the source is connected to a first voltage, the drain is connected to the light-emitting unit, and the bistable trigger is also connected to a second voltage. Based on the row scan signal and the light-emitting data signal, the second voltage is applied to the driving transistor to generate a driving current and drive the light-emitting unit to emit light, wherein the first voltage and the second voltage both correspond to the color of the light-emitting unit. The pixel driving circuit provided by the present invention can process the grayscale and color displayed by the light-emitting unit separately, and light-emitting units of different colors provide driving currents corresponding to the colors, so that light-emitting units of various colors can display all grayscales while also taking into account white balance, which can greatly improve the color display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 A schematic diagram illustrating an example of a traditional color display effect of a display panel;

[0039] Figure 2 A schematic diagram of the specific structure of the display panel according to an embodiment of the present application;

[0040] Figure 3 Schematic diagram of the overall structure of the pixel driving circuit according to an embodiment of the present application;

[0041] Figure 4 This is a structural diagram of the first power module in an embodiment of the present application;

[0042] Figure 5 This is a schematic structural diagram of the second power supply module in an embodiment of the present application;

[0043] Figure 6 A schematic diagram of a sub-field processing method for data to be displayed according to an embodiment of the present application;

[0044] Figure 7 A schematic diagram of a sub-field scanning timing sequence according to an embodiment of the present application;

[0045] Figure 8Schematic diagram of the structure of a column scanning circuit in a display panel according to an embodiment of the present application;

[0046] Figure 9 This is a schematic diagram illustrating an example of the color display effect of the display panel according to an embodiment of the present application;

[0047] Figure 10 Schematic diagram of the overall process of a pixel driving method according to an embodiment of the present application.

[0048] Reference numerals:

[0049] 100-light-emitting unit; 200-pixel driving circuit; 201 first input port; 202-second input port; 203-third input port; 210-first transistor; 220-second transistor; 230-driving transistor; 240-bistable trigger; 241-output port; 300-power supply module; 310-first power supply module; 311-first power supply submodule; 320-second power supply module; 321-second power supply submodule; 3211-voltage adjustable circuit; 3212-level converter; 330-third power supply module; 301-first signal line; 302-second signal line; 400-timing controller; 500-data processor; 600-column scanning circuit; 610-data line; 700-row scanning circuit; 710-scan line. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0051] In this application, the display panel may be, but is not limited to, a color silicon-based micro LED (Micro Light Emitting Diode) display panel, a color silicon-based OLED (Organic Light-Emitting Diode) display panel, an automotive color micro LED display panel, a mini LED (Mini Light Emitting Diode) display panel, an LED (Light-Emitting Diode) display panel, etc. Different types of display panels include corresponding types of light-emitting unit arrays.

[0052] The applicant noted that the current pixel driving circuit mainly includes two driving modes, analog driving and digital driving, in terms of grayscale realization. Analog driving is to adjust the luminous brightness of the light-emitting unit by adjusting the driving current flowing through the light-emitting unit, and digital driving is to adjust the luminous brightness of the light-emitting unit by adjusting the luminous time of the light-emitting unit. Compared with analog driving, each grayscale corresponds to a data voltage, that is, one data voltage corresponds to a luminous brightness of the light-emitting unit. The working state of the light-emitting unit in the digital driving circuit only includes bright state and dark state, wherein the working timing of the digital driving circuit includes "1" state timing and "0" state timing, "1" state corresponds to the bright state of the light-emitting unit, and "0" state corresponds to the dark state of the light-emitting unit. Digital driving realizes grayscale control by controlling the length of the light-emitting time of the light-emitting unit (that is, the length of the bright state and the length of the dark state).

[0053] Since the wavelength of the R (red) / G (green) / B (blue) LED will change according to the size of the driving current, and when the LED is driven by a small current, the brightness difference between each LED will be large, which will cause serious uneven display. This phenomenon is more serious when the LED is of a tiny size. Therefore, at present, digital driving is still mostly used for driving micro LEDs to avoid the above display problems. Digital driving mainly divides the scanning time of each frame of display screen into sub-fields of different sizes, and controls the light emission of each sub-field separately. The light emission time of each sub-field is combined to achieve the control of the total light emission time in this frame, thereby controlling the lighting time of each light-emitting unit in the display panel to achieve the effect of different grayscales for each light-emitting unit.

[0054] However, with the increasing requirements for resolution, frame rate, and display grayscale, the clock frequency requirements of this driving scheme have reached a peak level even for monochrome array displays. If a full-color RGB array display is implemented based on this scheme, the corresponding R / G / B full grayscale requirements will be difficult to achieve. This is because in a full-color display, white light (W) is obtained by adding the three primary colors of red (R), green (G), and blue (B). In order to achieve white balance, the luminous flux ratio of R / G / B is fixed under fixed color coordinate specifications.

[0055] See also Figure 1 , Figure 1 This example illustrates a traditional color display effect of a display panel. For example, under the color coordinate specifications of W (0.300, 0.315), R (0.682, 0.317), G (0.250, 0.710), and B (0.138, 0.051), the R / G / B luminous flux ratio ΦR:ΦG:ΦB = 3.18:9.27:1. To achieve a white screen with an L255 grayscale and a brightness of 1000 nits (brightness unit), the required R / G / B luminances are 236 nits, 689 nits, and 74 nits, respectively. Green has the highest luminous flux requirement, while blue has the lowest. At L255 grayscale, if the driving current of R / G / B light-emitting units is the same, due to the different luminous efficiency of each color, the luminous flux required for each color combination under white balance is also different. Assuming that the green light-emitting unit requires the longest luminous time and the red / blue light-emitting unit requires a shorter luminous time, then the following will appear under white balance. Figure 1 As shown, the green light-emitting unit (G LED) L255's corresponding lighting duration fully covers the effective lighting time of each sub-field within a frame. The red light-emitting unit (R LED) and the blue light-emitting unit (B LED) L255's corresponding lighting duration are shorter. Therefore, using existing digital driving methods, it is difficult to divide these smaller sub-fields into 256 grayscales. As a result, the number of grayscales for the red and blue light-emitting units is limited, failing to meet the 256 grayscale requirement. Alternatively, white balance may be impossible to achieve, and thus, poor color display quality may be achieved.

[0056] In view of this, an embodiment of the present application provides a pixel driving circuit for a display panel. By separately processing the grayscale and color displayed by the light-emitting unit, a driving current corresponding to the color is provided to the light-emitting units of different colors. In this way, the light-emitting duration required for the light-emitting units of the three colors of RGB at the same grayscale is consistent. By controlling the corresponding light-emitting duration, each color can achieve the display effect of all grayscales.

[0057] See also Figure 2 , Figure 2The specific structure of the display panel of an embodiment of the present application is illustrated. The display panel generally includes a timing controller 400, a data processor 500, a column scanning circuit 600, a row scanning circuit 700, and a plurality of pixel driving circuits 200 located in the display area and arranged in an array. The timing controller 400 is configured to generate various timing signals. The data processor 500 is connected to the timing controller 400, and is configured to receive data to be displayed and corresponding timing signals, and to generate a first data signal data (0 / 1) based on the data to be displayed and the timing signal. The column scanning circuit 600 is respectively connected to the data processor 500 and the plurality of pixel driving circuits 200, and is configured to generate a second data signal Data (0 / 1), that is, a light-emitting data signal, based on the received first data signal data (0 / 1), and transmit the light-emitting data signal to the corresponding pixel driving circuit 200 through the data line 610. The row scanning circuit 700 is connected to the timing controller 400 and the plurality of pixel driving circuits 200, and is configured to generate a row scanning signal Scan and a row clear signal Clear based on the scanning signal, and transmit the row scanning signal and the row clear signal to the corresponding pixel driving circuit 200 through the scanning line 710. Each pixel driving circuit 200 may be disposed in a space formed by the intersection of the scanning line 710 and the data line 610.

[0058] In addition, the pixel driving circuit 200 may also be connected to a power supply module 300, which is used to provide the required voltage for the pixel driving circuit 200. The power supply module 300 may include a first power supply module 310, a second power supply module 320, and a third power supply module 330. The first power supply module 310 may be configured to provide a first voltage V LED , the second power supply module 320 can be configured to provide a second voltage V GL , the third power supply module 330 can be configured to provide a third voltage V GH In addition, the power supply module 300 may further include a reference power supply module and a ground power supply module to respectively provide a reference voltage V to the corresponding pixel driving circuit 200. ref and ground voltage VSS. It is understood that the power module 300 may also be an integral device having multiple interfaces, each of which may be electrically connected to a corresponding pixel driving circuit 200 to output different voltages through different interfaces. As long as the function of providing different output voltages can be achieved, this embodiment of the present application does not specifically limit this.

[0059] The pixel driving circuit 200 according to an embodiment of the present application is described below.

[0060] See also Figure 3 , Figure 3The overall structure of the pixel driving circuit of an embodiment of the present application is illustrated. The pixel driving circuit 200 includes a light-emitting unit 100, a first transistor 210, a second transistor 220, a driving transistor 230, and a bistable trigger 240. The source of the first transistor 210 is connected to the light-emitting data signal, the gate of the first transistor 210 is connected to the row scan signal, and the drain of the first transistor 210 is electrically connected to the bistable trigger 240. The source of the second transistor 220 is electrically connected to the bistable trigger 240, the gate of the second transistor 220 is connected to the row clear signal, and the drain of the second transistor 220 is electrically connected to the drain of the first transistor 210. The gate of the driving transistor 230 is electrically connected to the bistable trigger 240, and the source of the driving transistor 230 is connected to the first voltage V LED The drain of the driving transistor 230 is electrically connected to the anode of the light emitting unit 100. The bistable trigger 240 is also connected to the second voltage V GL , and based on the row scan signal and the light emitting data signal, the second voltage V GL When the gate of the driving transistor 230 is loaded, the driving transistor 230 is driven according to the first voltage V LED and the second voltage V GL Generates a driving current and drives the light emitting unit 100 to emit light. The first voltage V LED and the second voltage V GL Both correspond to the colors of the light emitting unit 100 .

[0061] Specifically, the first transistor 210 is turned on when the row scan signal Scan addresses the pixel driving circuit 200 row by row, and stores the light emitting data signal on the flip-flop 240. The second transistor 220 clears the data on the flip-flop 240 when the row clear signal Clear addresses the pixel driving circuit 200 row by row. The driving transistor 230 switches the anode of the corresponding light emitting unit 100 to the first voltage V according to the data level on the flip-flop 240. LED , all the light emitting units 100 have a common cathode connected to the ground voltage VSS to control the lighting and extinguishing of the light emitting units 100 .

[0062] In some examples, the color of the light emitting unit 100 is any one of red, green and blue. The driving current I generated by the driving transistor 230 connected to the red light emitting unit 100 is dsR , the driving current I generated by the driving transistor 230 connected to the green light emitting unit 100 dsG The driving current I generated by the driving transistor 230 connected to the blue light emitting unit 100 dsB There is a ratio a:b:c between them, satisfying: a:b:c is equal to the ratio between the red luminous flux, green luminous flux and blue luminous flux corresponding to the white light under the color coordinates corresponding to the display panel.

[0063] For example, under the color coordinate specifications of W (0.300, 0.315), R (0.682, 0.317), G (0.250, 0.710), and B (0.138, 0.051), the luminous flux ratio of R / G / B is ΦR:ΦG:ΦB=3.18:9.27:1, so the driving currents corresponding to the three colors are I dsR , I dsG and I dsB The ratio between them is a:b:c=3.18:9.27:1.

[0064] Specifically, luminous flux is the integral of luminous intensity (instantaneous) and luminous duration. Luminous intensity (instantaneous) is proportional to the driving current and is the product of the driving current and the luminous efficiency of the light-emitting unit. The luminous efficiency is fixed under a fixed driving current. Therefore, first, the luminous flux of each color can be determined based on the maximum display brightness of the display panel and the luminous flux ratio of R / G / B under the corresponding color coordinate specification. Then, the luminous intensity (instantaneous) of each color can be determined based on the luminous flux of each color and the maximum luminous duration. Finally, the driving current corresponding to each color can be determined based on the luminous intensity (instantaneous) and luminous efficiency of each color. Specifically, the parameters can be calculated based on the conversion relationship of the relevant technology, which will not be described in detail in the embodiments of this application.

[0065] In this way, different driving currents are provided to the light-emitting units 100 of different colors, and the fixed ratio of the driving currents of different colors satisfies the color ratio of white light under the color coordinates corresponding to the display panel, so that the light-emitting units of the three colors of red, green and blue can all display all gray levels and take into account white balance, which can greatly improve the color display effect.

[0066] Please continue reading Figure 2 In some embodiments, the bistable flip-flop 240 may include a third transistor T1, a fourth transistor T2, a fifth transistor T3, and a sixth transistor T4. The third transistor T1, the fourth transistor T2, the fifth transistor T3, and the sixth transistor T4 form two inverters that are cross-coupled to form the bistable flip-flop 240.

[0067] Specifically, the source of the third transistor T1 and the source of the fifth transistor T3 are both electrically connected to the first input port 201, and the first input port 201 is configured to receive the third voltage V GHThe drain of the third transistor T1 and the drain of the fourth transistor T2 are both electrically connected to the drain of the first transistor 210, the gate of the third transistor T1 is electrically connected to the gate of the fourth transistor T2, a first node A is provided on the connection line between the gate of the third transistor T1 and the gate of the fourth transistor T2, the source of the fourth transistor T2 and the source of the sixth transistor T4 are both electrically connected to the second input port 202, and the second input port 202 is configured to receive the second voltage V GL , the source of the fourth transistor T2 is also electrically connected to the source of the second transistor 220 .

[0068] The gate of the fifth transistor T3 and the gate of the sixth transistor T4 are both electrically connected to the drain of the first transistor 210, the drain of the fifth transistor T3 is electrically connected to the drain of the sixth transistor T4, a second node B is provided on the connecting line between the drain of the fifth transistor T3 and the drain of the sixth transistor T4, the first node A is electrically connected to the second node B, the second node B is electrically connected to the output port 241, and the output port 241 is electrically connected to the gate of the driving transistor 230.

[0069] Exemplarily, the third transistor T1 , the fifth transistor T3 , and the driving transistor 230 are P-type transistors, and the first transistor 210 , the second transistor 220 , the fourth transistor T2 , and the sixth transistor T4 are N-type transistors.

[0070] Specifically, the working process of the bistable trigger 240 is as follows: the light emitting data signal is first loaded onto the Data line and transmitted to the source of the first transistor 210. When the row scan signal becomes a valid signal, the first transistor 210 is turned on, and the light emitting data signal is loaded onto the bistable trigger 240, which plays the role of holding the signal. When the light emitting data signal Data is "1", the sixth transistor T4 is turned on, and the second voltage V GL When the light emitting data signal Data is "0", the fifth transistor T3 is turned on, and the third voltage V GH The voltage is loaded to the gate of the driving transistor 230 . At this time, the driving transistor 230 is turned off and the light-emitting unit 100 does not emit light.

[0071] In some examples, the driving transistor 230 can be designed to operate in the saturation region, that is, |V gs -V th |<|V ds |, where V gs The second voltage V GL With the first voltage V LED The difference, V th is the threshold voltage of the driving transistor 230, V dsis the voltage difference between the drain and source of the driving transistor 230. Then the driving current received by the corresponding light emitting unit 100 is equal to the first voltage V LED and the second voltage V GL The following corresponding relationship is satisfied:

[0072]

[0073] Among them, I ds is the driving current, μ is the mobility of the driving transistor 230, C ox is the unit area capacitance of the gate oxide layer of the driving transistor 230, W is the channel width of the driving transistor 230, L is the channel length of the driving transistor 230, V gs The second voltage V GL With the first voltage V LED The difference, V gs =V GL -V LED ; V th is the threshold voltage of the driving transistor 230 .

[0074] Through the above example, the driving current I ds The magnitude of the second voltage V GL Or the first voltage V LED To make adjustments, the adjustment is relatively simple and easy to implement.

[0075] In other examples, the driving transistor 230 may be designed to operate in the mid-linear region, i.e., |V gs -V th |>|V ds |, where V gs The second voltage V GL With the first voltage V LED The difference, V th is the threshold voltage of the driving transistor 230, V ds is the voltage difference between the drain and source of the driving transistor 230. Then the driving current received by the corresponding light emitting unit 100 is equal to the first voltage V LED and the second voltage V GL The following corresponding relationship is satisfied:

[0076]

[0077] Among them, I ds is the driving current, μ is the mobility of the driving transistor 230, C ox is the unit area capacitance of the gate oxide layer of the driving transistor 230, W is the channel width of the driving transistor 230, L is the channel length of the driving transistor 230, V gs The second voltage V GLWith the first voltage V LED The difference, V gs =V GL -V LED ; V th is the threshold voltage of the driving transistor 230, V ds is the voltage difference between the drain and source of the driving transistor 230 .

[0078] Please also refer to Figure 2 and Figure 3 In some embodiments, the source of the driving transistor 230 is electrically connected to the third input port 203. The third input port 203 is configured to be electrically connected to the first power module 310 via the first signal line 301. The first power module 310 is configured to provide a first voltage corresponding to the color of the light-emitting unit 100. The second input port 202 is configured to be electrically connected to the second power module 320 via the second signal line 302. The second power module 320 is configured to provide a second voltage corresponding to the color of the light-emitting unit 100.

[0079] The first signal line 301 corresponding to the red light-emitting unit 100, the first signal line 301 corresponding to the green light-emitting unit 100, and the first signal line 301 corresponding to the blue light-emitting unit 100 are arranged on different layers of the display panel. And / or, the second signal line 302 corresponding to the red light-emitting unit 100, the second signal line 302 corresponding to the green light-emitting unit 100, and the second signal line 302 corresponding to the blue light-emitting unit 100 are arranged on different layers of the display panel. This not only facilitates wiring but also prevents interference between signals corresponding to different colors, thereby improving signal transmission quality.

[0080] It should be noted that, in order to better reflect the first signal line 301 and the second signal line 302 corresponding to the light emitting units 100 of different colors, Figure 2 In the figure, different line types are used to distinguish the first signal line 301 and the second signal line 302 corresponding to the light emitting units 100 of different colors.

[0081] In some examples, the first signal line 301 may include a first sub-signal line and a second sub-signal line intersecting each other, wherein the first sub-signal line extends along a first direction X of the display panel, and the second sub-signal line extends along a second direction Y of the display panel. The second signal line 302 may include a third sub-signal line and a fourth sub-signal line intersecting each other, wherein the third sub-signal line extends along the first direction X of the display panel, and the fourth sub-signal line extends along the second direction Y of the display panel.

[0082] Please also refer to Figure 4 and Figure 5 , Figure 4The structure of the first power module in the embodiment of the present application is illustrated. Figure 5 The structure of the second power supply module in the embodiment of the present application is illustrated. In some examples, the first power supply module 310 may include three first power supply submodules 311, each of which may be connected to the third input port 203 in the pixel driving circuit 200 that drives the light-emitting unit 100 of the corresponding color to provide a first voltage V corresponding to the color of the light-emitting unit 100. LED The second power supply module 320 may include three second power supply submodules 321, each of which may be connected to the second input port 202 in the pixel driving circuit 200 that drives the light emitting unit 100 of the corresponding color, so as to provide a second voltage V corresponding to the color of the light emitting unit 100. GL . In this way, the power supply module 300 can provide corresponding input voltages according to the driving current required by the connected light-emitting unit 100, thereby meeting the current proportionality requirement and being relatively simple to implement. It is understandable that the power supply module 300 can also be an integral device and have multiple interfaces, each of which can be electrically connected to the corresponding pixel driving circuit 200 to output different voltages through different interfaces. As long as the function of providing different input voltages to light-emitting units 100 of different colors can be achieved, the embodiments of the present application do not specifically limit this.

[0083] Illustratively, each second power submodule 321 may include a voltage adjustable circuit 3211 and a level converter 3212 connected to the voltage adjustable circuit 3211. The level converter 3212 is connected to the second input port 202 of the pixel driving circuit 200. In this way, the level converter 3212 can flexibly adjust the voltage output by the voltage adjustable circuit 3211 as needed, thereby reducing the difficulty of voltage regulation.

[0084] Please also refer to Figure 6 and Figure 7 , Figure 6 A sub-field processing method of data to be displayed in an embodiment of the present application is illustrated. Figure 7 A subfield scanning timing diagram of an embodiment of the present application is illustrated. The data to be displayed corresponding to each light-emitting unit can constitute a data stream to be displayed. After the data stream to be displayed enters the data processor 500, the data processor 500 extracts the grayscale information of each RGB color in the data stream to be displayed, and then processes it into data information for each subfield. Then, according to the subfield scanning timing provided by the row scanning circuit 700, each subfield is scanned and the data signal is written. Among them, the signal provided to the column scanning circuit 600 after data processing is a digital signal with only the state of "0" or "1".

[0085] For example, taking the grayscale accuracy of 8 bits as an example, the period of one frame can be divided into 8 subfields, namely SF1 to SF8. Taking four light-emitting units as an example, the corresponding grayscales are 128, 64, 0 and 200 respectively. Then, after each grayscale is represented in binary form, the grayscale values ​​of the four pixels corresponding to each subfield are extracted in parallel and converted into a serial manner. The data corresponding to SF1 is 0000, the data corresponding to SF2 is 0000, the data corresponding to SF3 is 0000, the data corresponding to SF4 is 0001, the data corresponding to SF5 is 0000, the data corresponding to SF6 is 0000, the data corresponding to SF7 is 0101, and the data corresponding to SF8 is 1001. Finally, according to Figure 6 The sub-field scanning timing shown is used to perform sub-field scanning and write data signals respectively. Figure 6 In the embodiment, Gate1 to GateN are row scan signals of each row, CLR1 to CLRN are row clear signals of each row, N is the total number of rows or columns of light-emitting units provided in the display panel array, DATA(0), DATA(4), and DATA(128) are data signals corresponding to grayscales, and DATA is the first data signal of each subfield.

[0086] The duration of the luminous phase of each subfield is different, that is, the lighting duration of the luminous unit is different. The setting method can be a standard binary weighted value increment or a non-standard binary weighted value increment. In the standard binary weighted value increment method, the ratio of the duration of the luminous phase of each subfield is 1(2 0 ):2(2 1 ):4(2 2 ):8(2 3 ):16(2 4 ):32(2 5 ):64(2 6 ):128(2 7 ). In this way, one frame of display data is the superposition of the display grayscale of each subfield, so that it can be displayed in 255 grayscale. It should be noted that in the embodiment of the present application, in order to improve the luminous brightness of the light-emitting unit L255 grayscale, when the scanning signal scans each row of light-emitting units, the light-emitting units in each row can emit light immediately after the addressing scanning time, and each light-emitting unit can continue to emit light during the driving time of the entire frame of the display image.

[0087] For example, to achieve 256 levels of grayscale adjustment for a single green Micro-LED array with a display frequency of 60Hz and a resolution of 1280x1024, eight subfields (denoted as subfields 1 to 8) constitute a single frame. The ratio of the luminous area width (i.e., the duration of the luminous phase) of the eight subfields is set to 1:2:4:8:16:32:64:128, and the data input to the eight subfields is denoted as d1 to d8. The grayscale of the displayed image is calculated as follows: Gray = 1 × d1 + 2 × d2 + 4 × d3 + 8 × d4 + 16 × d5 + 32 × d6 + 64 × d7 + 128 × d8. When the data input to subfield m is high, dm = 1; when the data input to subfield m is low, dm = 0. When the Data input to all subfields is at a high level, d1 to d8 are all 1, and Gray=256; when the Data input to all subfields is at a low level, d1 to d8 are all 0, and Gray=0.

[0088] See also Figure 8 , Figure 8 The structure of the column scanning circuit in the display panel of an embodiment of the present application is illustrated. The column scanning circuit 600 of the embodiment of the present application includes a shift register (shift), a latch (latch), and a level converter (levelshift) connected in sequence. The number of paths formed by the shift register (shift), the latch (latch), and the level converter (levelshift) is the same as the number of columns of the light-emitting unit array in the display panel. The shift register (shift) receives a reset signal (Reset), a clock signal (sclk), and a first data signal (data (0 / 1)), respectively. The latch (latch) also receives a clock signal (lclk). The shift register (shift) and the latch (latch) can perform serial-to-parallel conversion of data. The level converter (levelshift) can convert the potential corresponding to the "0" or "1" state into two potentials, one for turning off the light-emitting unit driver tube and the other for turning on the light-emitting unit driver tube.

[0089] In conjunction with the above description, the overall workflow of the display panel according to the embodiment of the present application is as follows: the data stream to be displayed enters the data processor 500, the timing controller 400 generates corresponding timing signals according to the set scanning algorithm to supply to the row scanning circuit 700, and generates corresponding timing signals to provide the timing required for data processing for the data processor 500. Then, the data processor 500 generates a first data signal based on the data stream to be displayed and the timing signal and transmits it to the column scanning circuit 600. At the same time, two sets of signals can be generated by the row scanning circuit 700, corresponding to the row scanning signal Scan and the row clear signal Clear, which are respectively connected to the gates of the first transistor 210 and the second transistor 220. The light-emitting data signal output by the column scanning circuit 600 is connected to the source of the first transistor 210.

[0090] See also Figure 9 , Figure 9 This illustrates an example of the color display effect of a display panel according to an embodiment of the present application. Using the drive system according to an embodiment of the present application to drive the display panel, the ratios a:b:c of the driving currents for the three colors B / R / G satisfy the luminous flux ratios of the B / R / G colors that make up white light W under fixed W / R / G / B color coordinate specifications. The light-emitting units of each color require consistent luminous duration at each grayscale, enabling full grayscale display by simply adjusting the luminous duration.

[0091] It can be understood that the pixel driving circuit provided in the embodiment of the present application can control the color and grayscale separately, adopt the digital sub-field scanning method to control the display grayscale of the light-emitting unit, and match the current of the light-emitting units of different colors in a fixed ratio to make the luminous flux ratio of different colors just meet the ratio of white light. As a result, the digital driving part only needs to complete the full grayscale of the number of monochrome resolution columns × 3 to achieve the full grayscale effect of full-screen color RGB. Not only is the digital driving architecture logic relatively simple and easy to implement, but it can also achieve better color display effects.

[0092] See accordingly Figure 10 , Figure 10 The overall process of a pixel driving method according to an embodiment of the present application is illustrated. The pixel driving method provided in the embodiment of the present application is used to drive a pixel driving circuit. Specifically, the method includes the following steps:

[0093] 1001: Based on the input row scan signal, the first transistor transmits the received light-emitting data signal to the bistable trigger when it is turned on.

[0094] 1002: Based on the light-emitting data signal, the bistable trigger applies the received second voltage to the gate of the driving transistor according to a set timing, so as to turn on the driving transistor.

[0095] 1003 : The driving transistor generates a driving current according to a first voltage received by the source and a second voltage received by the gate.

[0096] The first voltage and the second voltage both correspond to the color of the light-emitting unit.

[0097] In some examples, the color of the light-emitting unit is any one of red, green, and blue. The driving current received by the red light-emitting unit, the driving current received by the green light-emitting unit, and the driving current received by the blue light-emitting unit have a ratio a:b:c, satisfying: a:b:c is equal to the ratio of the red luminous flux, the green luminous flux, and the blue luminous flux corresponding to white light at the color coordinates corresponding to the display panel.

[0098] In some examples, when the driving transistor operates in a saturation region, the first voltage, the second voltage, and the driving current satisfy the following corresponding relationship:

[0099]

[0100] Among them, I ds is the driving current, μ is the mobility of the driving transistor, C ox is the unit area capacitance of the gate oxide layer of the driving transistor, W is the channel width of the driving transistor, L is the channel length of the driving transistor, V gs is the difference between the first voltage and the second voltage, V h is the threshold voltage of the driving transistor.

[0101] 1004: Based on the driving current and the on-time of the driving transistor, drive the light-emitting unit to emit light.

[0102] It can be understood that the pixel driving method of the embodiment of the present application can process the grayscale and color displayed by the light-emitting unit separately, and light-emitting units of different colors provide different driving currents, so that the fixed ratio of the driving currents of different colors can meet the color ratio of white light under the color coordinates corresponding to the display panel, thereby enabling the light-emitting units of the three colors of red, green and blue to realize the display of all grayscales, and also take into account the white balance, which can greatly improve the color display effect.

[0103] Correspondingly, an embodiment of the present application further provides a display panel, which includes the pixel driving circuit as described in the above embodiment.

[0104] It can be understood that the display panel of the embodiment of the present application can process the grayscale and color displayed by the light-emitting unit separately, and light-emitting units of different colors provide different driving currents, so that the fixed ratio of the driving currents of different colors can meet the color ratio of white light under the color coordinates corresponding to the display panel, so that the light-emitting units of the three colors of red, green and blue can all realize the display of all grayscales, and can also take into account white balance, which can greatly improve the color display effect.

[0105] The above is a detailed introduction to a pixel driving circuit, method and display panel provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A pixel driving circuit, applied to a display panel, characterized in that: include: a light emitting unit (100); a first transistor (210), wherein a source of the first transistor (210) is connected to a light emitting data signal, a gate of the first transistor (210) is connected to a row scanning signal, and a drain of the first transistor (210) is electrically connected to a bistable trigger (240); a second transistor (220), wherein the source of the second transistor (220) is electrically connected to the bistable trigger (240), the gate of the second transistor (220) is connected to a row clear signal, and the drain of the second transistor (220) is electrically connected to the drain of the first transistor (210); A driving transistor (230); the gate of the driving transistor (230) is electrically connected to the bistable trigger (240), the source of the driving transistor (230) is connected to a first voltage, and the drain of the driving transistor (230) is electrically connected to the anode of the light-emitting unit (100); The bistable trigger (240) is further connected to a second voltage, and when the second voltage is loaded onto the gate of the driving transistor (230) based on the row scan signal and the light-emitting data signal, the driving transistor (230) generates a driving current according to the first voltage and the second voltage and drives the light-emitting unit (100) to emit light, and the first voltage and the second voltage both correspond to the color of the light-emitting unit (100).

2. The pixel driving circuit according to claim 1, wherein: The color of the light-emitting unit (100) is any one of red, green and blue; The driving current generated by the driving transistor (230) connected to the red light-emitting unit (100), the driving current generated by the driving transistor (230) connected to the green light-emitting unit (100), and the driving current generated by the driving transistor (230) connected to the blue light-emitting unit (100) have a ratio a:b:c, satisfying that a:b:c is equal to the ratio between the red luminous flux, the green luminous flux, and the blue luminous flux corresponding to white light at the color coordinates corresponding to the display panel.

3. The pixel driving circuit according to claim 2, wherein: The bistable trigger (240) includes a third transistor (T1), a fourth transistor (T2), a fifth transistor (T3) and a sixth transistor (T4); The source of the third transistor (T1) and the source of the fifth transistor (T3) are both electrically connected to a first input port (201), the first input port (201) is connected to a third voltage, the drain of the third transistor (T1) and the drain of the fourth transistor (T2) are both electrically connected to the drain of the first transistor (210), the gate of the third transistor (T1) is electrically connected to the gate of the fourth transistor (T2), a first node (A) is provided on a connection line between the gate of the third transistor (T1) and the gate of the fourth transistor (T2), the source of the fourth transistor (T2) and the source of the sixth transistor (T4) are both electrically connected to a second input port (202), the second input port (202) is connected to the second voltage, and the source of the fourth transistor (T2) is also electrically connected to the source of the second transistor (220); The gate of the fifth transistor (T3) and the gate of the sixth transistor (T4) are both electrically connected to the drain of the first transistor (210), the drain of the fifth transistor (T3) is electrically connected to the drain of the sixth transistor (T4), a second node (B) is provided on the connection line between the drain of the fifth transistor (T3) and the drain of the sixth transistor (T4), the first node (A) is electrically connected to the second node (B), the second node (B) is electrically connected to an output port (241), and the output port (241) is electrically connected to the gate of the driving transistor (230).

4. The pixel driving circuit according to claim 3, wherein: The third transistor (T1), the fifth transistor (T3) and the driving transistor (230) are P-type transistors, and the first transistor (210), the second transistor (220), the fourth transistor (T2) and the sixth transistor (T4) are N-type transistors.

5. The pixel driving circuit according to claim 3, wherein: The source of the driving transistor (230) is electrically connected to a third input port (203), the third input port (203) is configured to be electrically connected to a first power supply module (310) via a first signal line (301), the first power supply module (310) is configured to provide the first voltage corresponding to the color of the light-emitting unit (100); The second input port (202) is configured to be electrically connected to a second power supply module (320) via a second signal line (302), and the second power supply module (320) is configured to provide the second voltage corresponding to the color of the light-emitting unit (100); The first signal line (301) corresponding to the red light-emitting unit (100), the first signal line (301) corresponding to the green light-emitting unit (100), and the first signal line (301) corresponding to the blue light-emitting unit (100) are arranged in different layers of the display panel; and / or the second signal line (302) corresponding to the red light-emitting unit (100), the second signal line (302) corresponding to the green light-emitting unit (100), and the second signal line (302) corresponding to the blue light-emitting unit (100) are arranged in different layers of the display panel.

6. The pixel driving circuit according to claim 1, wherein: When the driving transistor (230) operates in a saturation region, the first voltage, the second voltage, and the driving current satisfy the following corresponding relationship: Among them, I ds is the driving current, μ is the mobility of the driving transistor (230), C ox is the unit area capacitance of the gate oxide layer of the driving transistor (230), W is the channel width of the driving transistor (230), L is the channel length of the driving transistor (230), V gs is the difference between the first voltage and the second voltage, V th is the threshold voltage of the driving transistor (230).

7. A pixel driving method, characterized in that: For driving the pixel driving circuit according to any one of claims 1 to 6, the method comprising: Based on the input row scanning signal, the first transistor (210) transmits the received light emitting data signal to the bistable trigger (240) when it is turned on; Based on the light emitting data signal, the bistable trigger (240) loads the received second voltage to the gate of the driving transistor (230) according to a set timing, so as to turn on the driving transistor (230); The driving transistor (230) generates a driving current according to a first voltage received by the source and a second voltage received by the gate, wherein the first voltage and the second voltage both correspond to the color of the light-emitting unit (100); Based on the driving current and the conduction time of the driving transistor (230), the light emitting unit (100) is driven to emit light.

8. The pixel driving method according to claim 7, wherein: The color of the light-emitting unit (100) is any one of red, green and blue; The driving current received by the red light-emitting unit (100), the driving current received by the green light-emitting unit (100), and the driving current received by the blue light-emitting unit (100) have a ratio a:b:c, satisfying that a:b:c is equal to the ratio between the red luminous flux, the green luminous flux, and the blue luminous flux corresponding to white light under the color coordinates corresponding to the display panel.

9. The pixel driving method according to claim 7, wherein: When the driving transistor (230) operates in a saturation region, the first voltage, the second voltage, and the driving current satisfy the following corresponding relationship: Among them, I ds is the driving current, μ is the mobility of the driving transistor (230), C ox is the unit area capacitance of the gate oxide layer of the driving transistor (230), W is the channel width of the driving transistor (230), L is the channel length of the driving transistor (230), V gs is the difference between the first voltage and the second voltage, V th is the threshold voltage of the driving transistor (230).

10. A display panel, characterized in that: The device comprises a pixel driving circuit as claimed in any one of claims 1 to 6.

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