Display device
By working in concert with the timing controller and the scaling factor provider, the problem of current mismatch caused by process and temperature variations in pixel luminous efficiency was solved, enabling high-quality image display under different conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SAMSUNG DISPLAY CO LTD
- Filing Date
- 2021-08-25
- Publication Date
- 2026-05-15
AI Technical Summary
The luminous efficiency of pixels in a display device varies due to variations in manufacturing processes and ambient temperature, which can lead to incorrect current supply and affect image quality.
Through the coordinated operation of a timing controller, a data driver, and a scaling factor provider, the current value is calculated and adjusted to adapt to changes in pixel luminous efficiency and temperature. This includes a temperature sensor sensing the ambient temperature, a load weight calculator calculating the load weight, and a scaling factor provider generating appropriate scaling factors and current values.
This technology enables the application of appropriate current to pixels under different process and temperature conditions, thereby improving the quality of image display.
Smart Images
Figure CN114299850B_ABST
Abstract
Description
[0001] This application claims priority and benefit to Korean Patent Application No. 10-2020-0128206, filed on October 5, 2020, with the Korean Intellectual Property Office, which is incorporated herein by reference. Technical Field
[0002] The technical field relates to a display device and a method for driving the display device. Background Technology
[0003] Display devices typically consist of pixels. Image frames displayed by pixels can have different load values. For example, image frames corresponding to bright images can have large load values, and image frames corresponding to dark images can have small load values.
[0004] The amount of current required by a pixel can vary depending on the load value. To display the correct brightness, an appropriate amount of current needs to be supplied to the pixels corresponding to the load value of the image frame. However, the luminous efficiency of a pixel varies for different display areas due to variations in pixel manufacturing processes, and it also changes with ambient temperature.
[0005] If the wrong amount of current is supplied to the pixels, the quality of the image displayed by the display device will be unsatisfactory. Summary of the Invention
[0006] One object of the present invention is to provide a display device capable of providing appropriate current to pixels in response to variations in pixel manufacturing process and ambient temperature.
[0007] The embodiment may relate to a display device. The display device may include pixel devices, a timing controller, a data driver, and a scaling factor provider. The pixel devices may include pixels. Pixels may be divided into pixel groups. The timing controller may be electrically connected to the pixel devices, and may calculate a first load value corresponding to an image frame of input image data, and may generate image data by scaling the grayscale values of the input image data using a scaling factor. The data driver may be electrically connected to at least one of the pixel devices and the timing controller, and may generate a data signal corresponding to the image data, and may supply the data signal to the pixel devices. The scaling factor provider may calculate one or more second load values based on the first load value and temperature data corresponding to the temperature of the pixel devices, and may generate a scaling factor based on the one or more second load values and a common current value flowing through the pixels.
[0008] The scaling factor provider may include a unit target current value generator that generates a unit target current value based on the common current value corresponding to a reference pixel group within the pixel group.
[0009] The scaling factor provider may also include a scaling factor generator that generates a target current value based on a unit target current value and the one or more second load values, and generates a scaling factor based on the target current value and the common current value.
[0010] The timing controller can calculate the first load value corresponding to each pixel in the pixel group.
[0011] The scaling factor provider may also include a temperature calculator that calculates a predicted temperature data set for a group of pixels based on temperature data and a first load value.
[0012] The scaling factor provider may also include a load weight calculator that calculates load weights based on a predicted temperature dataset, a first weight dataset, and a second weight dataset.
[0013] Each element in the first weighted data set corresponds to the luminous efficiency value of a corresponding pixel group within a pixel group. Each element in the second weighted data set corresponds to the luminous efficiency of a pixel within a related pixel group, based on the temperature of the pixel device.
[0014] The load weight calculator calculates the load weight by multiplying the value from the corresponding second weight data set by the value from the corresponding first weight data set. The value from the corresponding second weight data set can correspond to the temperature of the pixel device based on the corresponding predicted temperature data set.
[0015] A pixel group may include a first pixel group and a second pixel group. The luminous efficiency for the first pixel group may be higher than that for the second pixel group. The value of the first weighted data set for the first pixel group may be lower than the value of the first weighted data set for the second pixel group.
[0016] The first temperature of the pixel device can be lower than the second temperature of the pixel device. The value of the second weighted data set for the first temperature of the pixel device can be greater than the value of the second weighted data set for the second temperature of the pixel device.
[0017] A pixel may include a first pixel containing a first light-emitting diode, a second pixel containing a second light-emitting diode, and a third pixel containing a third light-emitting diode. A load weight calculator can calculate a second weight data set for the first light-emitting diode, a second weight data set for the second light-emitting diode, and a second weight data set for the third light-emitting diode. The second weight data sets for the first light-emitting diode, the second weight data set for the second light-emitting diode, and the second weight data set for the third light-emitting diode may be unequal depending on the temperature of the pixel device.
[0018] The load weight calculator can calculate the load weight corresponding to each pixel group.
[0019] The scaling factor provider may include a load determiner that calculates one or more second load values based on a first load value and a load weight corresponding to a pixel group, respectively.
[0020] The load determiner can calculate one or more second load values for each pixel in a pixel group by multiplying the corresponding first load value by the corresponding load weight to produce a multiplied value and by adding the multiplied values.
[0021] The display device also includes a current sensor connected to the first power line and generating a common current value by sensing the current transmitted through the first power line.
[0022] The display device may include a temperature sensor that generates temperature data by sensing the temperature of the pixel device.
[0023] The embodiments may relate to a method of operating a display device. The display device may include a pixel device comprising pixels. Pixels may be divided into pixel groups. The method may include the following steps: calculating one or more first load values corresponding to image frames of input image data; calculating one or more second load values based on the one or more first load values and temperature data corresponding to the temperature of the pixel device; generating one or more scaling factors based on the one or more second load values and a common current value flowing through the pixels; generating image data by scaling the grayscale values of the input image data using the one or more scaling factors; generating a data signal corresponding to the image data; and supplying the data signal to the pixels to cause the pixels to emit light according to the data signal.
[0024] Generating a scaling factor may include the following steps: generating a unit target current value based on a common current value corresponding to a reference pixel group within the pixel group; generating a target current value based on the unit target current value and the one or more second load values; and generating the one or more scaling factors based on the target current value and the common current value.
[0025] Calculating the one or more second load values may include the following steps: calculating a predicted temperature data set for a pixel group based on temperature data and the one or more first load values; calculating a load weight based on the predicted temperature data set, a first weight data set, and a second weight data set; and calculating the one or more second load values based on the one or more first load values and the load weight.
[0026] Each element in the first weighted data set can correspond to the luminous efficiency value of a corresponding pixel group within the pixel group. Each element in the second weighted data set can correspond to the luminous efficiency of a pixel within its associated pixel group, based on the temperature of the pixel device.
[0027] According to an embodiment, the display device can perform global current control operation taking into account the luminous efficiency of pixels in a pixel group and the luminous efficiency of pixels according to ambient temperature. Therefore, appropriate current can be supplied to the pixels. Advantageously, satisfactory image display quality can be obtained. Attached Figure Description
[0028] Figure 1 This is a block diagram illustrating a display device according to an embodiment.
[0029] Figure 2 It is shown that, according to the embodiments, it includes Figure 1 The circuit diagram of the pixels in the display device.
[0030] Figure 3 This is a block diagram illustrating the scaling factor provider according to an embodiment.
[0031] Figure 4 It is shown that, according to the embodiments, it includes Figure 1 A diagram of the display panel in a display device.
[0032] Figure 5 This illustrates an embodiment in Figure 4 The diagram of the reference block set on the display panel.
[0033] Figure 6 It is a graph used to illustrate the luminous efficiency of a pixel according to (ambient) temperature according to an embodiment.
[0034] Figure 7A , Figure 7B and Figure 7C Each of these is a graph illustrating the load weight applied to a pixel based on (ambient) temperature according to an embodiment. Detailed Implementation
[0035] Example embodiments are described with reference to the accompanying drawings. Various modifications may be made to the described embodiments.
[0036] In the accompanying drawings, similar reference numerals may be used for similar elements, and the dimensions may be enlarged for clarity.
[0037] Terms such as "first" and "second" can be used to describe different elements, but elements should not be limited by the terms. These terms are used to distinguish one element from another. For example, a first component can be referred to as a second component, and / or a second component can be referred to as a first component. Describing an element as a "first" element does not require or imply the existence of a second or other element. The terms "first," "second," etc., can be used to distinguish different categories or sets of elements. For the sake of brevity, the terms "first," "second," etc., can respectively represent "first category (or first set)," "second category (or second set)," etc.
[0038] Unless the context clearly indicates otherwise, a singular expression may represent a plural expression.
[0039] The term "connection" can mean "electrical connection" or "electrical connection without an intermediate transistor." The term "insulation" can mean "electrical insulation" or "electrical isolation." The term "conduction" can mean "electrical conduction." The term "drive" can mean "operation" or "control." The expression "image frame" can refer to the data of an image frame.
[0040] Figure 1 This is a block diagram illustrating a display device according to an embodiment.
[0041] Reference Figure 1 The display device 1000 may include a display panel 100, a timing controller 200, a scan driver 300, a data driver 400, a current sensor 500, a temperature sensor 600, and a scaling factor provider 700.
[0042] The display panel 100 (pixel device) may include pixels PX. Each pixel PX may be connected to a corresponding data line and a corresponding scan line. Pixel PXij (where i and j are natural numbers) may represent a pixel whose scan transistor is connected to the i-th scan line SL1 and the j-th data line DLj, pixel PXi(j+1) may represent a pixel whose scan transistor is connected to the i-th scan line SL1 and the (j+1)-th data line DL(j+1), and pixel PX(i+1)j may represent a pixel whose scan transistor is connected to the (i+1)-th scan line SL(i+1) and the j-th data line DLj.
[0043] Pixel PX can be connected to a first power line VDDL and a second power line VSSL. Pixel PX can receive the voltage of a first power supply through the first power line VDDL and the voltage of a second power supply through the second power line VSSL. The voltages of the first and second power supplies can drive pixel PX, and the voltage level of the first power supply can be higher than the voltage level of the second power supply. For example, the voltage of the first power supply can be a positive voltage, and the voltage of the second power supply can be a negative voltage.
[0044] Pixels (PX) can share a common first power line (VDDL). Pixels (PX) can share a common second power line (VSSL). Pixels (PX) can be connected to different second power lines. Pixels (PX) can be connected to different first power lines.
[0045] The display panel 100 is divided into pixel groups including pixel groups BLKa and BLKb. Each of the pixel groups BLKa and BLKb may include at least one pixel. For example, the first pixel group BLKa may include pixels PXij and PX(i+1)j, and the second pixel group BLKb may include pixel PXi(j+1).
[0046] The timing controller 200 can receive input image data IDATA and control signals CS from an external source. The control signal CS may include a synchronization signal, a clock signal, etc. The input image data IDATA may include at least one image frame (data of at least one image frame).
[0047] The timing controller 200 can generate a first control signal SCS (scan control signal) and a second control signal DCS (data control signal) based on the control signal CS. The timing controller 200 can supply the first control signal SCS to the scan driver 300 and the second control signal DCS to the data driver 400.
[0048] The first control signal SCS may include a scan start signal, a clock signal, etc. The scan start signal controls the timing of the scan signals. The clock signal included in the first control signal SCS can be used to shift the scan start signal.
[0049] The second control signal DCS may include a source start signal, a clock signal, etc. The source start signal controls the starting point of data sampling. The clock signal included in the second control signal DCS controls the sampling operation.
[0050] The timing controller 200 can calculate the frame load value FL1 (first load value) corresponding to each image frame of the input image data IDATA. The frame load value FL1 can correspond to the grayscale value of the image frame. For example, as the sum of the grayscale values of the image frames increases, the frame load value FL1 of the corresponding image frame can increase.
[0051] For example, the frame load value FL1 can be 100 in a pure white image frame, and FL1 can be 0 in a pure black image frame. A pure white image frame can represent an emitting image frame with maximum brightness, in which all pixels PX of the display panel 100 are set to maximum grayscale (white grayscale) to emit light. A pure black image frame can represent a non-emitting image frame, in which all pixels PX of the display panel 100 are set to minimum grayscale (black grayscale). The frame load value FL1 can be in the range of 0 to 100.
[0052] The timing controller 200 can calculate a frame load value FL1 for each pixel group in the display panel 100. The frame load value FL1 can include a frame load value corresponding to each of the pixel groups BLKa and BLKb.
[0053] The timing controller 200 can provide the calculated frame payload value FL1 to the scaling factor provider 700, and can use the scaling factor SF received from the scaling factor provider 700 to scale the grayscale values of the input image data IDATA. The scaling factor SF can be applied collectively to all pixels PX of the display panel 100. The grayscale values of the input image data IDATA can be scaled by the same ratio based on the scaling factor SF.
[0054] The timing controller 200 can generate image data DATA by rearranging the input image data IDATA obtained by scaling grayscale values, and can provide the generated image data DATA to the data driver 400.
[0055] The scan driver 300 can receive a first control signal SCS from the timing controller 200 and can provide scan signals to scan lines SL1, SL2, SL3 to SLn (where n is a natural number) based on the first control signal SCS. For example, the scan driver 300 can provide scan signals sequentially to scan lines SL1 to SLn. If the scan signals are provided sequentially, pixels PX are selected on a horizontal line basis (or on a pixel row basis), and data signals can be supplied to the selected pixels PX. The scan signals can be set to a gate on-voltage (low voltage or high voltage) such that the transistor included in each of the pixels PX and receiving the scan signal is turned on.
[0056] The data driver 400 can receive image data DATA and a second control signal DCS from the timing controller 200, and can supply data signals (data voltages) corresponding to the image data DATA to data lines DL1, DL2, DL3 to DLm (where m is a natural number) in response to the second control signal DCS. The data signals supplied to data lines DL1 to DLm can be supplied to pixels PX selected by the scan lines. The data driver 400 can supply data signals to data lines DL1 to DLm synchronously with the scan signal.
[0057] Since the image data DATA is generated based on the input image data IDATA obtained by scaling the grayscale values with a scaling factor SF, the data driver 400 can supply data signals corresponding to the scaled grayscale values to data lines DL1 to DLm. For example, the data driver 400 can apply a data signal corresponding to the scaled grayscale value of pixel PXij to the j-th data line DLj, and can apply a data signal corresponding to the scaled grayscale value of pixel PXi(j+1) to the (j+1)-th data line DL(j+1).
[0058] The current sensor 500 can be connected to a first power line VDDL that is commonly connected to the pixel PX. The current sensor 500 can supply a global current value GC (common current value) to the scaling factor provider 700 by sensing the current through the first power line VDDL. The global current value GC can correspond to the current commonly supplied to all pixels PX through the first power line VDDL. The current sensor 500 can also sense the current through the second power line VSSL that is commonly connected to the pixel PX.
[0059] The display device 1000 emits light from a pixel group designated as a reference pixel group. The current sensor 500 senses the current passing through the first power line VDDL, generates a global current value GC, and supplies the generated global current value GC to the scaling factor provider 700. The scaling factor provider 700 can store a unit target current value corresponding to the global current value GC in a memory.
[0060] The storage operation of the unit target current value can be performed once when the display device 1000 is started. The timing and number of times the unit target current value is stored can be set according to the embodiment.
[0061] The scaling factor provider 700 can generate a target current value based on a unit target current value and a frame load value FL1, and can generate a scaling factor SF by comparing the global current value GC provided from the current sensor 500 with the target current value. For example, the scaling factor provider 700 can determine the ratio between the target current value and the global current value GC as the scaling factor SF. For example, the scaling factor provider 700 can determine the scaling factor SF such that if the global current value GC is greater than the target current value, the grayscale value of pixel PX is scaled smaller. As another example, the scaling factor provider 700 can determine the scaling factor SF such that if the global current value GC is less than the target current value, the grayscale value of pixel PX is scaled larger. The above driving process can be referred to as Global Current Management (GCM).
[0062] The luminous efficiency level of a pixel (PX) can vary due to variations in its manufacturing process. For example, the luminous efficiency levels of the light-emitting diodes (LEDs) included in the pixel (e.g., LEDs emitting red light, LEDs emitting green light, LEDs emitting blue light, etc.) can differ. The luminous efficiency level of a pixel (PX) can also vary depending on the ambient temperature of the display device 1000. For example, the LEDs included in the pixel (PX) can have different luminous efficiency levels depending on the ambient temperature. The luminous efficiency level of a pixel (PX) can represent its luminous brightness in relation to the current supplied to it. When the display device 1000 (scale factor provider 700) performs global current control operation regardless of the different luminous efficiency levels of the pixel (PX), the current supplied to the pixel (PX) may not be optimal, causing the pixel (PX) to emit light with a brightness different from the target brightness.
[0063] To compensate for variations in the luminous efficiency level of pixel PX, the display device 1000 (and / or the scaling factor provider 700) may take into account variations in the luminous efficiency level of pixel PX to determine the scaling factor SF.
[0064] Temperature sensor 600 can generate temperature data TD by sensing the ambient temperature of display device 1000 (and / or display panel 100). Temperature sensor 600 can provide temperature data TD to scaling factor provider 700.
[0065] The scaling factor provider 700 can calculate the correction load value (second load value) by using temperature data TD from temperature sensor 600 and applying weights to the frame load value FL1 based on the luminous efficiency level for each in the pixel group and the temperature-dependent luminous efficiency level of pixel PX stored in memory / .
[0066] The scaling factor provider 700 can generate a target current value based on the corrected load value and a unit target current value. For example, the scaling factor provider 700 can generate a target current value by multiplying the corrected load value by the unit target current value. The scaling factor provider 700 can also generate a scaling factor SF based on the target current value and the global current value GC provided from the current sensor 500.
[0067] The display device 1000 (and / or the scaling factor provider 700) can perform global current control operations by taking into account the luminous efficiency level of each pixel group and the luminous efficiency level of the pixel PX according to the ambient temperature. Advantageously, by taking into account process variations of the pixel PX and variations in ambient temperature, an appropriate current can be supplied to the pixel PX.
[0068] The scaling factor provider 700 can be implemented in a separate integrated circuit (IC) different from the timing controller 200. All or part of the scaling factor provider 700 can be integrated into the same IC as the timing controller 200. All or part of the scaling factor provider 700 can be implemented in software within the timing controller 200.
[0069] Figure 2 It is shown that, according to the embodiments, it includes Figure 1 The circuit diagram of the pixels in the display device.
[0070] Reference Figure 2 The pixel PXij includes transistors T1 and T2, a storage capacitor Cst, and a light-emitting diode LD.
[0071] The circuit may include an N-type transistor. The circuit may include a P-type transistor. The circuit may include at least one P-type transistor and at least one N-type transistor. For a P-type transistor, the amount of current conducted can increase when the voltage difference between the gate and source electrodes increases in the negative direction. For an N-type transistor, the amount of current conducted can increase when the voltage difference between the gate and source electrodes increases in the positive direction. The transistor can be a thin-film transistor (TFT), a field-effect transistor (FET), or a bipolar junction transistor (BJT).
[0072] A first transistor T1 can be connected between a first power line VDDL and a light-emitting diode LD, and its gate electrode can be connected to a first node N1. The first transistor T1 can control the amount of current flowing from the first power line VDDL to the second power line VSSL via the light-emitting diode LD in response to the voltage at the first node N1. The first transistor T1 can be referred to as a driving transistor.
[0073] The second transistor T2 can be connected between the data line DLj and the first node N1, and its gate electrode can be connected to the scan line SLi. When a scan signal is supplied to the scan line SLi, the second transistor T2 is turned on, allowing the data line DLj and the first node N1 to be electrically connected to each other. Therefore, the data signal can be transmitted to the first node N1. The second transistor T2 can be referred to as the scan transistor.
[0074] The storage capacitor Cst can be connected between the first node N1 corresponding to the gate electrode of the first transistor T1 and the second electrode of the first transistor T1. The storage capacitor Cst can store the voltage corresponding to the voltage difference between the gate electrode and the second electrode of the first transistor T1.
[0075] The first electrode (anode or cathode) of the light-emitting diode (LED) can be connected to the second electrode of the first transistor T1, and the second electrode (cathode or anode) of the LED can be connected to the second power supply line VSSL. The LED can generate light with a predetermined brightness in response to the amount of current (drive current) supplied from the first transistor T1.
[0076] Light-emitting diodes (LDs) can be organic light-emitting diodes. LDs can also be inorganic light-emitting diodes, such as micro LEDs or quantum dot LEDs. LDs can comprise both organic and inorganic materials. Figure 2 In this context, pixel PXij comprises a single light-emitting diode (LD). Pixel PXij may include multiple light-emitting diodes, and these diodes may be connected in series, in parallel, or in a series-parallel connection.
[0077] The voltage of the first power supply can be supplied to the first power supply line VDDL, and the voltage of the second power supply can be applied to the second power supply line VSSL. The voltage of the first power supply can be greater than the voltage of the second power supply.
[0078] If a scan signal with a conduction level (e.g., a logic high level) is applied through the scan line SL1, the second transistor T2 is turned on. At this time, the voltage corresponding to the data signal applied to the data line DLj can be stored in the first node N1 (the first electrode of the storage capacitor Cst).
[0079] The drive current corresponding to the voltage difference between the first and second electrodes of the storage capacitor Cst can flow between the first and second electrodes of the first transistor T1. Therefore, the light-emitting diode LD can emit light with a brightness level corresponding to the data signal.
[0080] Depend on Figure 1The global current value GC provided by the current sensor 500 can be obtained by summing the drive current values of all pixels PX flowing through the display panel 100. This is because... Figure 1 The scaling factor SF generated by the scaling factor provider 700 scales the grayscale value accordingly to adjust the size of the data signal, thus allowing adjustment of the drive current value of the pixel PX.
[0081] Figure 2 The structure of pixel PXij can be applied to other pixels of display panel 100. Pixel PXij may also include a transistor that electrically connects the second electrode of the first transistor T1 and the first electrode of the light-emitting diode LD, and / or the first electrode of the first transistor T1 and the first power line VDDL, when turned on by a control signal. Pixel PXij may also include a sensing transistor that senses the voltage or current applied to the second electrode of the first transistor T1 or the first electrode of the light-emitting diode LD and transmits the sensed current to the sensing line when turned on by a sensing signal supplied through a separate sensing line.
[0082] Figure 3 This is a block diagram illustrating the scaling factor provider according to an embodiment. Figure 4 It is shown that, according to the embodiments, it includes Figure 1 A diagram of the display panel in a display device. Figure 5 It is used to illustrate the embodiments. Figure 4 The image of the reference pixel group in the display panel. Figure 6 It is a graph used to illustrate the luminous efficiency level of pixels according to temperature values according to the embodiment. Figure 7A , Figure 7B and Figure 7C Each of these is a graph illustrating the load weight value applied to a pixel based on the temperature value.
[0083] The display device 1000 (and / or the scaling factor provider 700) can set at least one pixel group among the pixel groups as a reference pixel group to perform a unit target current value UTC storage operation.
[0084] Reference Figure 4 The pixels PX of the display panel 100 can be divided into multiple pixel groups BLK11, BLK12, BLK13, BLK14, BLK15, BLK21, BLK22, BLK23, BLK24, BLK25, BLK31, BLK32, BLK33, BLK34, and BLK35. Each of the pixel groups BLK11 to BLK35 may include at least one pixel. The total number of pixel groups BLK11 to BLK35 may be equal to or less than the total number of pixels of the display panel 100.
[0085] By dividing the display panel 100 into pixel groups BLK11 to BLK35 of the same size, each pixel group BLK11 to BLK35 may include the same number of pixels. In an embodiment, all or some of the pixel groups BLK11 to BLK35 may share one or more pixels, and / or some of the pixel groups BLK11 to BLK35 may include more pixels than other pixel groups.
[0086] Figure 4 The display panel 100 is shown to be divided into 15 pixel groups BLK11 to BLK35. The display panel 100 may be divided into fewer or more pixel groups, such as 100 pixel groups.
[0087] Return to reference Figure 3 , Figure 4 and Figure 5 When the display device 1000 is activated, it can emit light from a reference pixel group RBLK among pixel groups BLK11 to BLK35. The reference pixel group RBLK may correspond to pixel group BLK23 located at the center of the display panel 100. The reference pixel group RBLK may be located at other locations. For example, the reference pixel group may be a pixel group located outside the display panel 100. As another example, two or more pixel groups among pixel groups BLK11 to BLK35 may be designated as the reference pixel group.
[0088] Pixels included in the reference pixel group RBLK can emit light at the highest gray level (e.g., white gray level), and the remaining pixel group can remain silent (e.g., remain at the black gray level).
[0089] At this time, the current sensor 500 can generate a global current value GC by sensing the current flowing through the first power line VDDL, and can provide the global current value GC to the unit target current value generator 760 of the scaling factor provider 700.
[0090] The unit target current value generator 760 can generate a unit target current value UTC corresponding to the global current value GC of the reference pixel group RBLK. For example, the unit target current value generator 760 can store the global current value GC corresponding to the reference pixel group RBLK as the unit target current value UTC on / in the second memory 770. Figure 4 and Figure 5As shown, one of the 15 pixel groups BLK11 to BLK35 (e.g., pixel group BLK23) is designated as the reference pixel group RBLK. When the display device 1000 is powered on, the pixels included in the reference pixel group RBLK can emit light with the highest grayscale, while the remaining pixel groups do not emit light. Therefore, the unit target current value UTC can be equal to the global current value GC, which corresponds to approximately 6.67% or 1 / 15 of the current value of a full-white image frame. When the display panel 100 is divided into 100 pixel groups, one of the 100 pixel groups designated as the reference pixel group can emit light with the highest grayscale, while the remaining pixel groups do not emit light. Therefore, the unit target current value UTC can be equal to the global current value GC, which corresponds to approximately 1% or 1 / 100 of the current value of a full-white image frame.
[0091] In this embodiment, the unit target current value UTC can be generated when the display device 1000 is started, can be stored on / in the second memory 770 of the scaling factor provider 700, and can be used during the display period of the image frame of the display device 1000 thereafter.
[0092] The scaling factor provider 700 can generate a scaling factor SF by taking into account the variation in the luminous efficiency level of pixel PX for a pixel group and the variation in the luminous efficiency level of pixel PX according to ambient temperature.
[0093] The scaling factor provider 700 may include a temperature calculator 710, a load weight calculator 720, a first memory 730, a load determiner 740, a scaling factor generator 750, a unit target current value generator 760, and a second memory 770. The unit target current value generator 760 can generate a unit target current value UTC corresponding to the global current value GC corresponding to the reference pixel group RBLK, and the second memory 770 can store the unit target current value UTC.
[0094] The temperature calculator 710 can receive temperature data TD from the temperature sensor 600 and can receive frame load value FL1 from the timing controller 200. The timing controller 200 can calculate the frame load value FL1 for each of the pixel groups BLK11 to BLK35.
[0095] The temperature calculator 710 can calculate predicted temperature data BTD for each of the pixel groups BLK11 to BLK35 based on temperature data TD and the frame load value FL1 calculated for the corresponding pixel group in pixel groups BLK11 to BLK35. The temperature of the pixel groups BLK11 to BLK35 of the display panel 100 can vary depending on the frame load value FL1. For example, the temperature of a pixel group with a high frame load value FL1 can be higher than the temperature of a pixel group with a low frame load value FL1.
[0096] The temperature calculator 710 may include a lookup table storing values of predicted temperature data BTD corresponding to a predetermined frame load value FL1. Therefore, the temperature calculator 710 can use the lookup table to calculate the predicted temperature data BTD corresponding to the frame load value FL1 for each of the pixel groups BLK11 to BLK35.
[0097] The load weight calculator 720 can use the predicted temperature data BTD from the temperature calculator 710 and the first weight data BLW and the second weight data TLW from the first memory 730 to calculate the load weight LW.
[0098] The first weighted data BLW can correspond to the luminous efficiency of each of pixel groups BLK11 to BLK35. The luminous efficiency level for pixel groups BLK11 to BLK35 can vary due to process variations. The luminous efficiency level of the light-emitting diodes (LEDs) included in pixel PX (e.g., LEDs emitting red light, LEDs emitting green light, LEDs emitting blue light, etc.) can be different for pixel groups BLK11 to BLK35. Corresponding to pixel groups BLK11 to BLK35, the first weighted data BLW can include weighted data BLW1 based on the luminous efficiency for red grayscale, weighted data BLW2 based on the luminous efficiency for green grayscale, and weighted data BLW3 based on the luminous efficiency for blue grayscale. When the luminous efficiency is high for the same supply current, pixel PX can emit light with high brightness. Therefore, for each of pixel groups BLK11 to BLK35, when the luminous efficiency of each of the red grayscale, green grayscale, and blue grayscale is high, the weighted data BLW1, weighted data BLW2, and weighted data BLW3 can be small. The first weight data BLW corresponding to the pixel group with the minimum luminous efficiency for each of the red, green, and blue grayscale levels can have a value of 1. The first weight data BLW corresponding to the remaining pixel groups can have values corresponding to the luminous efficiency level of the pixel group with the minimum luminous efficiency. As an example, when the pixel group with the minimum luminous efficiency has 6 cd / A for red grayscale, the weight data BLW1 corresponding to the pixel group with the minimum luminous efficiency can have a value of 1, and the weight data BLW1 corresponding to the pixel group with 6.6 cd / A can have a value of approximately 0.91 or 6 / 6.6.
[0099] A test current corresponding to the input image data IDATA for each of the red, green, and blue grayscale values is applied to each of the pre-shipment pixel groups BLK11 to BLK35 of the display panel 100. At this time, the luminous efficiency of the red, green, and blue grayscale values corresponding to each of the pixel groups BLK11 to BLK35 can be measured based on the measured luminous intensity. The first weighted data BLW can be stored in the first memory 730 in the form of a lookup table.
[0100] The second weighted data TLW can correspond to the luminous efficiency of a pixel based on ambient temperature. The luminous efficiency of a first pixel including a first light-emitting diode emitting red light, the luminous efficiency of a second pixel including a second light-emitting diode emitting green light, and the luminous efficiency of a third pixel including a third light-emitting diode emitting blue light can vary depending on the ambient temperature. The second weighted data TLW can be stored in the first memory 730 in the form of a lookup table.
[0101] Reference Figure 6 The diagram shows the luminous efficiency levels (in cd / A) of light-emitting diodes based on ambient temperature (temperature unit: °C). The diagram also shows the luminous efficiency levels of a first light-emitting diode emitting red light, a second light-emitting diode emitting green light, and a third light-emitting diode emitting blue light.
[0102] like Figure 6 As shown, at 0°C, the luminous efficiency corresponding to the second LED is 10 cd / A, the first LED is 7 cd / A, and the third LED is 5 cd / A. As the temperature increases, the luminous efficiency of each LED decreases. For example, at 100°C, the luminous efficiency corresponding to the second LED is 7.5 cd / A, the first LED is 6 cd / A, and the third LED is 4.5 cd / A. Because the materials included in the LEDs differ, the degree to which the luminous efficiency decreases with increasing temperature can vary for each LED.
[0103] The second weighted data TLW may include weighted data TLW1 corresponding to the first LED, weighted data TLW2 corresponding to the second LED, and weighted data TLW3 corresponding to the third LED. The weighting rate of the second weighted data TLW based on temperature may be different for different LEDs.
[0104] Reference Figure 7A , Figure 7B and Figure 7CAt 100°C, all of the weighted data TLW1, TLW2, and TLW3 can have a value of 1; at 0°C, weighted data TLW1 can have a value of 0.7, weighted data TLW2 can have a value of 0.6, and weighted data TLW3 can have a value of 0.9. For each of the light-emitting diodes, at the temperature corresponding to the minimum luminous efficiency (e.g., 100°C), the second weighted data TLW can have a value of 1; below the temperature of minimum luminous efficiency, the second weighted data TLW can be determined by applying different weight change rates to different light-emitting diodes.
[0105] The load weight calculator 720 can calculate the load weight LW corresponding to each of the pixel groups BLK11 to BLK35 based on the predicted temperature data BTD, the first weight data BLW, and the second weight data TLW.
[0106] The load weight calculator 720 calculates the weight for each of the red, green, and blue grayscale values of a pixel group by multiplying a corresponding weight data TLW1, TLW2, and TLW3 based on the temperature of the pixel group with a corresponding weight data BLW1, BLW2, and BLW3 for that pixel group. The temperature corresponds to the predicted temperature data BTD for one of the pixel groups BLK11 to BLK35. The load weight LW for the pixel group can be calculated by multiplying the weights for red, green, and blue grayscale values. The load weight calculator 720 can also calculate the load weight LW for each of the pixel groups BLK11 to BLK35 by applying the luminous efficiency variation for pixel groups BLK11 to BLK35 and the luminous efficiency variation of the light-emitting diodes according to ambient temperature.
[0107] Reference Figure 3 The load determiner 740 can determine the load value FL1 for each received frame in pixel groups BLK11 to BLK35 from the timing controller 200, and the load weight calculator 720 can determine the received load weight LW for each received frame in pixel groups BLK11 to BLK35.
[0108] The load determiner 740 can calculate the corrected load value FL2 based on the frame load value FL1 and the load weight LW. For example, the load determiner 740 can calculate the corrected load value FL2 for each of the pixel groups BLK11 to BLK35 by multiplying the frame load value FL1 by the load weight LW and summing all the multiplied values.
[0109] The scaling factor generator 750 can determine the target current value based on the unit target current value UTC received from the unit target current value generator 760 and the corrected load value FL2 received from the load determiner 740. For example, the scaling factor generator 750 can determine the target current value by multiplying the unit target current value UTC by the corrected load value FL2. The scaling factor generator 750 can generate a scaling factor SF by comparing the target current value with the global current value GC received from the current sensor 500. For example, the scaling factor generator 750 can determine the scaling factor SF as the ratio between the target current value and the global current value GC.
[0110] The display device 1000 (and / or the scaling factor provider 700) can perform global current control operations taking into account the luminous efficiency variations of pixel groups BLK11 to BLK35 and the luminous efficiency variations of pixel PX based on ambient temperature. Therefore, an appropriate current can be supplied to pixel PX. Advantageously, the display device 1000 can display images with satisfactory quality.
[0111] The above embodiments are illustrative. Actual embodiments can be implemented in various combinations, changes, environments, and / or modifications within the scope defined by the appended claims.
Claims
1. A display device, the display device comprising: A pixel device, comprising pixels connected to a first power line, the pixels being divided into pixel groups; A timing controller, electrically connected to the pixel device, calculates a first load value corresponding to an image frame of the input image data, and generates image data by scaling the grayscale value of the input image data using a scaling factor. A data driver, electrically connected to at least one of the pixel device and the timing controller, generates a data signal corresponding to the image data and supplies the data signal to the pixel device; A scaling factor provider calculates one or more second load values based on the first load value and temperature data corresponding to the temperature of the pixel device, and generates the scaling factor based on the one or more second load values and the common current value flowing through the pixel; as well as A current sensor is connected to the first power line and generates a common current value by sensing the current transmitted through the first power line. The scaling factor provider includes: A unit target current value generator generates a unit target current value based on a common current value corresponding to a reference pixel group within the pixel group; and A scaling factor generator generates a target current value based on the unit target current value and the one or more second load values, and generates the scaling factor based on the target current value and the common current value flowing through the pixel.
2. The display device according to claim 1, wherein, The timing controller calculates a first load value corresponding to each of the pixel groups.
3. The display device according to claim 2, wherein, The scaling factor provider also includes a temperature calculator that calculates a predicted temperature data set for the pixel group based on the temperature data and the first load value corresponding to each of the pixel groups.
4. The display device according to claim 3, wherein, The scaling factor provider also includes a load weight calculator, which calculates the load weight based on the predicted temperature data set, the first weight data set, and the second weight data set.
5. The display device according to claim 4, wherein, Each element in the first weighted data set corresponds to the luminous efficiency value of a corresponding pixel group within the pixel group, and Each of the second weighted data sets corresponds to the luminous efficiency of a pixel in a related pixel group according to the temperature of the pixel device.
6. The display device according to claim 5, wherein, The load weight calculator calculates the load weight by multiplying the value from the corresponding second weight data set by the value from the corresponding first weight data set. The value from the corresponding second weighted data set corresponds to the temperature of the pixel device based on the corresponding predicted temperature data set.
7. The display device according to claim 1, further comprising: A temperature sensor that generates the temperature data by sensing the temperature of the pixel device.