Disclosure of Invention
The invention aims to provide a method, a system and a driving circuit for displaying of an analog and digital hybrid driving display unit, which can reduce power consumption, reduce the design requirement of a driving chip, obviously improve the gray scale and color level expression capability of an image and realize high-contrast and high-dynamic range display.
In order to solve the technical problems, the invention adopts the following technical scheme.
A method of displaying by an analog and digital hybrid driven display unit, the display unit being a sub-pixel, a row of pixels, a display area made up of any number of pixels, or all pixels of an active matrix light emitting display device or apparatus, the method comprising:
simulating the driving quantity to control the light-emitting brightness of the display unit;
under the light emission luminance, the digital driving amount controls the light emission time of the display unit.
Before the analog driving quantity and the digital driving quantity control the display unit to emit light, the method further comprises the following steps:
determining the combination mode of the analog driving quantity and the digital driving quantity for controlling the display unit to emit light.
The determining a combination of the analog driving amount and the digital driving amount for controlling the display unit to emit light includes:
analyzing and obtaining the brightness characteristics of all display units in one frame of image through an image analysis algorithm;
determining at least one brightness threshold of the display unit according to the designed or tested light emitting characteristics of the display unit;
determining a combination of the analog driving amount and the digital driving amount for controlling the display unit to emit light based on the obtained luminance characteristic and the determined luminance threshold.
The luminance characteristic is one of an average luminance characteristic, a maximum luminance characteristic, a minimum luminance characteristic, or a luminance distribution characteristic.
The specific method for determining the combination manner of the analog driving quantity and the digital driving quantity for controlling the display unit to emit light according to the obtained brightness characteristic and the determined brightness threshold value is as follows:
when the brightness characteristic of the display unit is larger than the brightness threshold value of the display unit, increasing the analog driving quantity for controlling the display unit to emit light, and reducing the switching times and/or time for controlling the digital driving quantity for controlling the display unit to emit light, or reducing the analog driving quantity for controlling the display unit to emit light, and increasing the switching times and/or time for controlling the digital driving quantity for controlling the display unit to emit light;
or, when the luminance characteristic of the display unit is less than or equal to the luminance threshold value of the display unit, the analog driving amount for controlling the light emission of the display unit is decreased, and the number of switching times and/or time for controlling the digital driving amount for the light emission of the display unit is increased, or the analog driving amount for controlling the light emission of the display unit is increased, and the number of switching times and/or time for controlling the digital driving amount for the light emission of the display unit is decreased.
A display system for an analog and digital hybrid driving display unit, the display unit being a sub-pixel, a row of pixels, a display area made up of any number of pixels, or all pixels of an active light emitting display device or apparatus, the system comprising:
an analog driving unit for outputting an analog driving quantity for controlling the light emission luminance of the display unit;
and the digital driving unit is used for outputting digital driving quantity for controlling the light-emitting time of the display unit under the light-emitting brightness.
The display device further comprises an image data analysis processing unit which is used for determining the combination mode of the analog driving quantity and the digital driving quantity for controlling the display unit to emit light before the analog driving unit and the digital driving unit control the display unit to emit light.
The determining a combination of the analog driving amount and the digital driving amount for controlling the display unit to emit light includes:
analyzing and obtaining the brightness characteristics of all display units in one frame of image through an image analysis algorithm;
determining at least one brightness threshold of the display unit according to the designed or tested light emitting characteristics of the display unit;
determining a combination of the analog driving amount and the digital driving amount for controlling the display unit to emit light based on the obtained luminance characteristic and the determined luminance threshold.
The luminance characteristic is one of an average luminance characteristic, a maximum luminance characteristic, a minimum luminance characteristic, or a luminance distribution characteristic.
The specific method for determining the combination manner of the analog driving quantity and the digital driving quantity for controlling the display unit to emit light according to the obtained brightness characteristic and the determined brightness threshold value is as follows:
when the brightness characteristic of the display unit is larger than the brightness threshold value of the display unit, increasing the analog driving quantity for controlling the display unit to emit light, and reducing the switching times and/or time for controlling the digital driving quantity for controlling the display unit to emit light, or reducing the analog driving quantity for controlling the display unit to emit light, and increasing the switching times and/or time for controlling the digital driving quantity for controlling the display unit to emit light;
or, when the luminance characteristic of the display unit is less than or equal to the luminance threshold value of the display unit, the analog driving amount for controlling the light emission of the display unit is decreased, and the number of switching times and/or time for controlling the digital driving amount for the light emission of the display unit is increased, or the analog driving amount for controlling the light emission of the display unit is increased, and the number of switching times and/or time for controlling the digital driving amount for the light emission of the display unit is decreased.
A driving circuit for analog and digital hybrid driving, comprising:
a driving transistor having a gate for inputting a digital driving amount, a drain electrically connected to an anode of the display unit, and a cathode electrically connected to a common voltage;
a first switch unit, a first end of which is used for inputting analog driving quantity and a second end of which is used for inputting scanning signals;
a second switching unit, a first end of which is electrically connected with the source electrode of the driving transistor, a second end of which is electrically connected with a third end of the first switching unit, and a third end of which is electrically connected with a working voltage anode;
the second end of the first switch unit controls the connection or disconnection of the first end and the third end of the first switch unit; the second end of the second switch unit controls the connection or disconnection of the first end and the third end of the second switch unit.
And the capacitor is bridged between the third end of the first switch unit and the common ground.
The present invention has the following advantageous technical effects.
The invention utilizes the analog driving quantity to control the luminous brightness of the display unit; meanwhile, at this light emission luminance, the light emission time of the display unit is controlled by the digital driving amount. The display unit is controlled to emit light through the combination of the light-emitting brightness and the light-emitting time, richer gray scales and colors are realized, the problem of trailing of a high-frequency digital driving mode is solved, the limitation of DAC performance on high-resolution analog driving is also solved, the gray scale and color scale expression capability of an image is remarkably improved, high-contrast and high-dynamic-range display is realized, and meanwhile, the system power consumption and the design requirement of a driving chip are reduced.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The embodiments and features of the embodiments of the present invention may be arbitrarily combined with each other without conflict. Also, while a logical order is shown in the flow diagrams, in some cases, the steps shown or described may be performed in an order different than here.
Unless specifically stated otherwise, the terms "first," "second," and "third" herein do not denote any order or importance, nor do they denote any order or importance.
In addition, the term "and/or" herein is only one kind of association relationship describing an associated object, and means that there may be three kinds of relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone.
The invention can be applied to active light-emitting display devices or equipment such as LED, OLED, QLED, Micro-LED and Micro-OLED.
In the present invention, an active light emitting display device or apparatus such as an OLED is composed of a plurality of pixels, each of which includes a plurality of sub-pixels. The active light emitting display device or apparatus may be classified into an RGB system and an RGBW system according to the class of sub-pixels, each pixel of the RGB system including 1 red sub-pixel, 1 green sub-pixel, and 1 blue sub-pixel. Recent RGBW systems include 1 red subpixel, 1 green subpixel, 1 blue subpixel, and 1 white subpixel.
For example, the OLED is an organic electroluminescent display device, the driving circuit inputs a specific voltage or current to the OLED sub-pixel, and after passing through the compensation circuit of the OLED sub-pixel, the current flows through the light-emitting material, and the OLED sub-pixel is lit to start emitting light, as shown in fig. 1, which is an OLED driving circuit with a typical 2T1C structure. The conventional OLED display driving method is to apply an analog excitation signal of voltage or current to the OLED sub-pixels, as in S101 of fig. 1. The control of the light emitting brightness of the OLED sub-pixel is achieved by controlling the intensity of the voltage or current analog signal input to the sub-pixel, as in S201 of fig. 2. In the conventional analog signal driving method, the lighting time of each OLED sub-pixel is the same, as in S301 of fig. 3.
In order to realize image display with high gray scale, high contrast and high dynamic range, the conventional driving method requires that the driving chip must be cut into 256-level or even higher display gray scales by a high-precision digital-to-analog converter within a smaller driving voltage or driving current range. This puts high demands on the driving chip, the manufacturing process and the material, and also directly affects the yield of the product. Meanwhile, in a conventional analog driving mode using voltage driving or current driving, for example, the OLED subpixels are driven to emit light, the light emitting time of each OLED subpixel is the same, and even the OLED subpixels with lower gray scales need to maintain the light emitting time of almost one frame, which greatly increases the difficulty of gray scale control of low gray scale images and also causes waste of power consumption, and is not favorable for power consumption control of active light emitting display devices or equipment such as OLEDs, QLEDs, Micro-OLEDs, and the like.
In the invention, the display unit can be a sub-pixel, a row of pixels, a display area composed of any plurality of pixels or all pixels of an active light emitting display device or equipment such as an LED, an OLED, a QLED, a Micro-LED and a Micro-OLED. For example, the display unit may be an LED sub-pixel, an OLED sub-pixel, a QLED sub-pixel, or a Micro-OLED sub-pixel, or the display unit may also be a row of LED sub-pixels, a row of OLED pixels, a row of QLED pixels, or a row of Micro-OLED pixels, and so on.
In order to overcome the defects of the traditional driving mode, the invention provides the following technical scheme.
The invention provides a method for displaying by an analog and digital hybrid driving display unit, which comprises the following steps: simulating the driving quantity to control the light-emitting brightness of the display unit; under the light emission luminance, the digital driving amount controls the light emission time of the display unit.
The conventional driving methods for active light emitting display devices or devices such as LEDs, OLEDs, QLEDs, Micro-LEDs, and Micro-OLEDs use analog driving methods, such as voltage driving or current driving, and control the luminance of the display unit by controlling the intensity of analog driving quantities such as voltage or current, so as to realize different display gray scales and colors, as shown in fig. 2. In this driving manner, each display unit of the active light emitting display device or apparatus such as LED, OLED, QLED, Micro-OLED, etc. has the same lighting time, as shown by S301 in fig. 3. On the basis of the structure and the driving mode of the existing display unit, the digital driving mode is introduced, as shown in fig. 4, under the condition of the luminous brightness of the display unit L controlled by the analog driving quantity, the luminous time of the display unit is controlled by the digital driving quantity, so that the display unit can display more gray scales, and the design difficulty of an analog driving IC is reduced. Therefore, the invention realizes richer gray scale and color through the combination of the luminous brightness and the luminous time, and simultaneously reduces the system power consumption and the design difficulty of the analog drive IC.
The principle of the digital driving mode is that the integral effect of the radiation intensity of the same light radiation intensity on the retina of human eyes and the action time t enables the human eyes to generate brightness difference to form different gray scales and colors.
In the formula (1), Ψ (t) represents the instantaneous light emission luminance.
The digital driving method is realized by controlling the lighting time of each display unit, such as each OLED sub-pixel or each row of OLED sub-pixels, under the condition of a certain analog driving quantity, and realizing the display gray scale between different display units under the same analog driving quantity through the integral effect of the radiation intensity of the same light radiation intensity on the retina of human eyes and the action time t. At this time, the instant light emitting brightness of each display unit is the same, because the lighting time is different, and the brightness difference is generated to realize the display gray scale, as shown in S302, S303, S304 in fig. 3.
It can be seen that the present invention controls the light emission of the display unit in a hybrid manner of analog driving and digital driving, i.e., controls the brightness of the display unit by an analog driving amount, such as current driving or voltage driving, and controls the lighting time of the display unit by a digital driving amount, such as a PWM signal. For example, one OLED sub-pixel (e.g., S401 in fig. 6), one OLED pixel (e.g., S501 in fig. 7), one row of OLED pixels (e.g., S601 in fig. 8), a display region composed of any number of OLED pixels (e.g., S701 in fig. 9), or all OLED pixels (e.g., S801 in fig. 10) are driven in a manner of mixing analog driving and digital driving, so that gray scales and colors of one sub-pixel, one row of pixels, a display region composed of any number of pixels, or all pixels in one frame of image are precisely controlled, thereby realizing high contrast and high dynamic range display.
For example, in the analog driving method, n gradations, a (0), a (1), and a (2) … … a (n) are defined. In the digital driving method, m gradations are defined, and D (0), D (1), and D (2) … … D (m), respectively. Then theoretically the color level G of each display element is:
g ═ a (x) × D (y), x ≦ 0 ≦ N, y ≦ 0 ≦ m, and x, y ∈ N;
considering the repeated gray scale, the total gray scale number that can be covered by the analog driving and the digital drivingWherein,indicating the number of permutations.
For prime number gray scale, the direct analog driving and one-time digital driving can not be realized, and the digital driving can be realized by two times or even multiple times. For example, the implementation of the 59 gray level (denoted as G59) can be as follows: g59 ═ G58+ G1 or G59 ═ G56+ G3. First, the gray scale of 58 is realized at the first lighting, and then the gray scale of 1 is realized at the second lighting, and the luminance equivalent to the gray scale of 59 is realized by the human eye integration effect, as shown by S304 in fig. 3.
In a display system of mixed analog and digital driving, the selection of the analog driving amount and the digital driving amount is important. In practical applications, for example, a dedicated image data analysis processing unit may be designed to perform analysis processing on the image data, as shown in fig. 5. For example, before the analog driving amount and the digital driving amount control the display unit to emit light, a combination manner of the analog driving amount and the digital driving amount that control the display unit to emit light is determined.
Determining a combination of an analog driving amount and a digital driving amount for controlling light emission of the display unit includes: the brightness characteristics of all display units in one frame of image are obtained through image analysis algorithm analysis. The display unit may be, for example, one sub-pixel, one pixel unit, one row of pixels, a display area composed of any number of pixels, or all pixels in the frame image. And determining at least one brightness threshold of the display unit according to the designed or tested light emitting characteristics of the display unit. And then determining a combination mode of the analog driving quantity and the digital driving quantity for controlling the display unit to emit light according to the obtained brightness characteristic and the determined brightness threshold value so as to realize better display effect.
In the present invention, the luminance characteristic is one of an average luminance characteristic, a maximum luminance characteristic, a minimum luminance characteristic, and a luminance distribution characteristic.
The following description will be made of how to determine the combination of the analog driving amount and the digital driving amount for controlling the light emission of the display unit, taking the luminance characteristic as the average luminance characteristic as an example.
Average brightness statistics is firstly carried out on the brightness of all display units in each frame of image,
APL is the average luminance, N is the total number of rows of video, the total number of columns of video, Pi,jThe display units in the ith row and the jth column in the image are, for example, the aforementioned OLED sub-pixels.
And then determining one or more average brightness thresholds according to different values of the APL and the luminous characteristics of the display unit obtained by design or test, and selecting different combination modes of analog driving quantity and digital driving quantity. Regarding the combination of the digital driving amount and the analog driving amount, different combinations may be adopted for each frame image for better display effect. The basis for the different combinations is the statistical APL of the average luminance of the display elements in the frame of image.
The APLth is an average brightness threshold, which is determined by factors such as an image processing algorithm and a light emitting display device or equipment, such as an OLED production process, in practice, the value of the APLth needs to be confirmed according to a sample test result, and the APLth may be one or more. For example, one or more average brightness thresholds may be determined according to the physical characteristics of the display screen (each screen/no batch of screens may be different), and when the average brightness of the frame image obtained by statistics falls within different average brightness threshold intervals, a combination of corresponding digital driving quantity and analog driving quantity may be adopted. In different display screens, the value of APLth can be one or more, and corresponds to a combination mode of two or more analog driving and digital driving.
For example, when an APLth is taken, the combination of the analog driving quantity and the digital driving quantity is:
wherein,indicating that the analog drive function for each display cell is driven with a smaller analog drive current or voltage when the average brightness is less than or equal to APLth.
ρ0(Pi,j) It is shown that when the average brightness is less than or equal to APLth, the number of times and/or time of digital driving is increased for the digital driving function of each display unit, so that a low gray scale image can be better represented.
Indicating that the analog drive function for each display cell is driven with a larger analog drive current or voltage when the average brightness is greater than APLth.
ρ1(Pi,j) Indicating that the digital drive function for each display cell reduces the number of switching times and/or the time of the digital drive when the average brightness is greater than APLth.
For example, when the average luminance of the display unit is greater than APLth of the display unit, the analog driving amount controlling the light emission of the display unit is increased and the number of times and/or time of switching of the digital driving amount controlling the light emission of the display unit is decreased, or the analog driving amount controlling the light emission of the display unit is decreased and the number of times and/or time of switching of the digital driving amount controlling the light emission of the display unit is increased. When the average brightness of the display unit is less than or equal to APLth of the display unit, the analog driving quantity for controlling the light emission of the display unit is reduced, and the number of times and/or time of switching the digital driving quantity for controlling the light emission of the display unit is increased, or the analog driving quantity for controlling the light emission of the display unit is increased, and the number of times and/or time of switching the digital driving quantity for controlling the light emission of the display unit is reduced. The difference between the number of switching times and/or time for decreasing the analog driving amount and increasing the digital driving amount and the number of switching times and/or time for increasing the analog driving amount and decreasing the digital driving amount is that the specific gravity is different in the combination of the digital driving amount and the analog driving amount. For example, to achieve a display luminance of 100, combination 1: analog 30, digital 70; and (3) combination 2: analog 70, digital 30. The core of the invention is to change the existing single digital drive or analog drive into the combination of digital drive and analog drive, thus overcoming various disadvantages of the single drive mode.
According to the method, the gray scales and colors of one sub-pixel, one line of pixels, a display area consisting of any plurality of pixels or all pixels of the active light emitting display devices or equipment such as the LED, the OLED, the QLED, the Micro-LED and the Micro-OLED are accurately controlled, and the display effects of low power consumption, high contrast and high dynamic range are realized while the analog driving circuits of the active light emitting display devices or equipment such as the LED, the OLED, the QLED, the Micro-OLED are simplified.
FIG. 5 is a schematic diagram of a system architecture for display of an analog and digital hybrid driving display unit according to the present invention. The system for displaying by the analog and digital mixed driving display unit comprises an image data analysis processing unit 1, an analog driving unit 2 and a digital driving unit 3.
The analog driving unit 2 is used to output an analog driving amount for controlling the light emission luminance of the display unit.
The digital driving unit 3 is used to output a digital driving amount for controlling the light emitting time of the display unit at the light emitting luminance.
The image data analysis processing unit 1 is for determining the combination of the analog driving amount and the digital driving amount for controlling the display unit to emit light before the analog driving unit 2 and the digital driving unit 3 control the display unit to emit light.
In some embodiments, determining a combination of the analog driving amount and the digital driving amount to control the light emission of the display unit includes:
determining the combination mode of the analog driving quantity and the digital driving quantity for controlling the display unit to emit light.
In some embodiments, determining the combination of the analog driving amount and the digital driving amount to control the light emission of the display unit comprises:
analyzing and obtaining the brightness characteristics of all display units in one frame of image through an image analysis algorithm;
determining at least one brightness threshold of the display unit according to the designed or tested light emitting characteristics of the display unit;
determining a combination of the analog driving amount and the digital driving amount for controlling the display unit to emit light based on the obtained luminance characteristic and the determined luminance threshold.
In some embodiments, the luminance characteristic is one of an average luminance characteristic, a highest luminance characteristic, a lowest luminance characteristic, or a luminance distribution characteristic.
In some embodiments, the specific method for determining the combination of the analog driving quantity and the digital driving quantity for controlling the display unit to emit light according to the obtained luminance characteristic and the determined luminance threshold value is as follows:
when the brightness characteristic of the display unit is larger than the brightness threshold value of the display unit, increasing the analog driving quantity for controlling the display unit to emit light, and reducing the switching times and/or time for controlling the digital driving quantity for controlling the display unit to emit light, or reducing the analog driving quantity for controlling the display unit to emit light, and increasing the switching times and/or time for controlling the digital driving quantity for controlling the display unit to emit light;
or, when the luminance characteristic of the display unit is less than or equal to the luminance threshold value of the display unit, the analog driving amount for controlling the light emission of the display unit is decreased, and the number of switching times and/or time for controlling the digital driving amount for the light emission of the display unit is increased, or the analog driving amount for controlling the light emission of the display unit is increased, and the number of switching times and/or time for controlling the digital driving amount for the light emission of the display unit is decreased.
The display unit may be one sub-pixel, one row of pixels, a display area composed of any number of pixels, or all pixels of an active light emitting display device or apparatus.
Fig. 4 is a schematic diagram of a structure of a driving circuit for analog and digital hybrid driving according to the present invention. The invention relates to a drive circuit for analog and digital mixed drive, which comprises a drive transistor T3, a first switch unit 4 and a second switch unit 5.
The gate of the driving transistor T3 is used to input a digital driving amount, and its drain is electrically connected to the anode of the display cell L whose cathode is electrically connected to the common voltage Vcom.
The first switch unit 4 has a first terminal 41 for inputting an analog driving amount and a second terminal 42 for inputting a Scan signal Scan.
The second switching unit 5 has a first terminal 51 electrically connected to the source of the driving transistor T3, a second terminal 52 electrically connected to the third terminal 43 of the first switching unit 4, and a third terminal 53 electrically connected to the positive operating voltage Vdd.
Wherein, the second end 42 of the first switch unit 4 controls the connection or disconnection of the first and third ends 41, 43 of the first switch unit 4; the second terminal 52 of the second switch unit 5 controls the first and third terminals 51, 53 of the second switch unit 5 to be connected or disconnected.
The first switch unit 4 includes an N-channel MOS transistor T1, wherein a first terminal 41 is a drain of the N-channel MOS transistor, a second terminal 42 is a gate of the N-channel MOS transistor, and a third terminal is a source of the N-channel MOS transistor.
The second switching unit 5 includes a P-channel MOS transistor T2, wherein a first end 51 thereof is a drain of the P-channel MOS transistor, a second end 52 thereof is a gate of the P-channel MOS transistor, and a third end thereof is a source of the P-channel MOS transistor.
The driving transistor T3 is a P-channel MOS transistor.
In a possible embodiment, the analog and digital hybrid driving circuit of the present invention further comprises a capacitor C connected across the third terminal 43 of the first switching unit 4 and the common ground GND.
Therefore, regarding the functions that can be realized by each functional unit in the analog and digital hybrid driving display unit display system, reference may be made to the corresponding description in the embodiment of the method of the present invention, and details are not repeated.
In the embodiments provided by the present invention, it should be understood that the disclosed system and method can be implemented in other ways. For example, the above-described system embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, systems or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, i.e. may be located in one place, or may be distributed over a plurality of network elements. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor (processor) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium/unit includes: various media capable of storing program codes, such as a Universal Serial Bus flash disk (usb flash disk), a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, and an optical disk.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.