Backlight module, driving method thereof and display module

Abstract

The application provides a backlight module and a driving method thereof and a display module, and relates to the technical field of display, which can improve the chromaticity deviation problem of the display module. The backlight module comprises a backlight source and a backlight driving unit. The backlight source comprises a white light source and a compensation light source. The backlight driving unit comprises a main driving module and a compensation driving module. The main driving module is electrically connected with the white light source and the compensation driving module, and is configured to: in a compensation period, select a compensation driving function corresponding to a current environment temperature according to the current environment temperature; provide a compensation control signal to the compensation driving module according to the selected compensation driving function; the compensation driving module is configured to: acquire the compensation control signal and provide a driving signal to the compensation light source according to the compensation control signal; and the compensation light source is configured to: acquire the driving signal and emit light under the driving of the driving signal, so that the change value of the white point color coordinate of the display module in the compensation period is within a preset range.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a backlight module and its driving method, and a display module. Background Technology

[0002] Professional LCD display modules used in medical, film and television production, and electronic signage typically feature high brightness and a wide color gamut. Due to the high color gamut, the color filter is thicker, resulting in lower panel transmittance. Therefore, the LCD module needs to increase backlight brightness to meet these requirements. Increasing backlight brightness necessitates increasing the number of LEDs (Light Emitting Diodes) and the LED drive current, inevitably leading to heat generation issues. Display modules typically require 30-60 minutes to reach temperature stability at room temperature. During this temperature rise, color shifts occur (primarily affecting white areas), degrading display quality. Summary of the Invention

[0003] The embodiments of this application adopt the following technical solutions:

[0004] On one hand, a backlight module is provided for use in a display module; the backlight module includes: a backlight source and a backlight driving unit; the backlight source includes: a white light source and a compensation light source, the white light source has an emission wavelength range of a first wavelength range, and the compensation light source has an emission wavelength range of a second wavelength range, the second wavelength range being located within the first wavelength range; the backlight driving unit includes: a main driving module and a compensation driving module;

[0005] The main driving module is electrically connected to both the white light source and the compensation driving module, and is configured to: during the compensation period, select a compensation driving function corresponding to the current ambient temperature, wherein the compensation period refers to the time from the initial startup of the display module to the thermal equilibrium time, and the compensation driving function includes the correspondence between the driving current of the compensation light source and the ambient temperature; and provide a compensation control signal to the compensation driving module according to the selected compensation driving function.

[0006] The compensation driving module is configured to: acquire and provide a driving signal to the compensation light source according to the compensation control signal;

[0007] The compensation light source is configured to: acquire the driving signal and emit light under the drive of the driving signal, so that the change value of the white point color coordinate of the display module during the compensation period is within a preset range.

[0008] Optionally, the working efficiency η of the compensation light source satisfies:

[0009]

[0010] Where t represents time. The thermal equilibrium time of the display module is given by , and A is the module influence factor.

[0011] Optionally, the compensation light source includes a blue light source;

[0012] Alternatively, the compensation light source may include a blue light source and a red light source;

[0013] Alternatively, the compensation light source may include a red light source, a green light source, and a blue light source.

[0014] Optionally, the compensation light source includes a blue light source;

[0015] The white point color coordinates (x, y) of the display module when the white light source and the compensation light source are activated during the compensation period, and the white point color coordinates (x0, y0) of the display module when the white light source is activated but the compensation light source is not activated during the compensation period, satisfy the following:

[0016]

[0017] in, The intensity ratio of the blue light source to the white light source is given. The influence factor of blue light on the x-color coordinate. The influence factor of blue light on the y-coordinate.

[0018] Optional, 0≤ ≤10%; -0.08≤ ≤-0.01; -0.2≤ ≤-0.07.

[0019] Optionally, the compensation light source includes a blue light source and a red light source;

[0020] The white point color coordinates (x, y) of the display module when the white light source and the compensation light source are activated during the compensation period, and the white point color coordinates (x0, y0) of the display module when the white light source is activated but the compensation light source is not activated during the compensation period, satisfy the following:

[0021]

[0022] in, , These are the intensity ratios of the red light source and the blue light source relative to the white light source, respectively. , These are the influence factors of red light and blue light on the x-color coordinate, respectively. , These are the influence factors of red light and blue light on the y-coordinate, respectively.

[0023] Optional, 0≤ ≤10%, 0≤ ≤10%;

[0024] -0.08≤ ≤-0.01, 0.07≤ ≤0.2;

[0025] -0.2≤ ≤-0.07, -0.012≤ ≤-0.005.

[0026] Optionally, the compensation light source includes a red light source, a green light source, and a blue light source;

[0027] The white point color coordinates (x, y) of the display module when the white light source and the compensation light source are activated during the compensation period, and the white point color coordinates (x0, y0) of the display module when the white light source is activated but the compensation light source is not activated during the compensation period, satisfy the following:

[0028]

[0029] in, , 、 These are the intensity ratios of the red light source, the green light source, and the blue light source relative to the white light source, respectively. 、 、 These are the influence factors of red, green, and blue light on the x-color coordinate, respectively. 、 、 These are the influence factors of red light, green light, and blue light on the y-coordinate, respectively.

[0030] Optional, 0≤ ≤10%, 0≤ ≤10%, 0≤ ≤10%;

[0031] 0.07≤ ≤0.2, -0.2≤ ≤0.2、-0.08≤ ≤-0.01;

[0032] -0.012≤ ≤-0.005, 0.15≤ ≤0.3、-0.2≤ ≤-0.07.

[0033] Optionally, the backlight module further includes a light guide plate, with the white light source and the compensation light source positioned on opposite sides of the light guide plate.

[0034] Optionally, the backlight module further includes a diffuser plate and a reflector, with the white light source and the compensation light source disposed between the diffuser plate and the reflector, and the compensation light source disposed around the white light source.

[0035] Optionally, the white light source includes multiple white light emitting units, and the compensation light source includes multiple compensation emitting units, wherein the number of compensation emitting units is less than the number of white light emitting units.

[0036] Optionally, the backlight module further includes a temperature monitoring unit, which is electrically connected to the main drive module;

[0037] The temperature monitoring unit is configured to: collect the ambient temperature and transmit the ambient temperature information to the main drive module during the compensation period; the main drive module is also configured to: acquire the ambient temperature information.

[0038] Optionally, the backlight module further includes a heat dissipation unit, which is electrically connected to the main drive module;

[0039] The main drive module is further configured to transmit a first control signal to the heat dissipation unit when the ambient temperature is higher than a first set temperature; the first set temperature is lower than the thermal equilibrium temperature of the display module.

[0040] The heat dissipation unit is configured to activate or increase its heat dissipation power according to the first control signal transmitted by the main drive module.

[0041] Optionally, the main drive module is further configured to: transmit a second control signal to the heat dissipation unit when the ambient temperature is lower than the second set temperature; the second set temperature is lower than the first set temperature;

[0042] The heat dissipation unit is configured to shut down or reduce its heat dissipation power according to the second control signal transmitted by the main drive module.

[0043] Optionally, the preset range is -0.002 to +0.002.

[0044] Optionally, the main drive module is further configured to: preset multiple compensation drive functions, each compensation drive function corresponding to a different ambient temperature.

[0045] Optionally, the ambient temperatures corresponding to the multiple compensation driving functions are sorted in ascending order, and the absolute value range of the difference between adjacent ambient temperatures is 3 to 7°C.

[0046] On the other hand, a display module is provided, including: a display panel and the aforementioned backlight module, wherein the backlight module is disposed on the backlight side of the display panel.

[0047] In another aspect, a driving method for a backlight module is provided, wherein the backlight module is applied to a display module, and the driving method includes:

[0048] During the compensation period, the main drive module selects a compensation drive function corresponding to the current ambient temperature based on the current ambient temperature. The compensation period refers to the time from the initial startup time to the thermal equilibrium time of the display module, and the compensation drive function includes the correspondence between the driving current of the compensation light source and the ambient temperature.

[0049] The main drive module provides a compensation control signal to the compensation drive module according to the selected compensation drive function;

[0050] The compensation driving module acquires and provides a driving signal to the compensation light source according to the compensation control signal;

[0051] The compensation light source acquires the driving signal and emits light under the drive of the driving signal, so that the change value of the white point color coordinate of the display module during the compensation period is within a preset range.

[0052] Optionally, before the main drive module selects the compensation drive function corresponding to the current ambient temperature during the compensation period, the method further includes:

[0053] The main drive module presets multiple compensation drive functions, each of which corresponds to a different ambient temperature.

[0054] Optionally, the main driving module presets multiple compensation driving functions, including:

[0055] Establish multiple compensation driving functions;

[0056] Multiple compensation driving functions are built into the main driving module.

[0057] Optionally, establishing the compensation driving function includes:

[0058] The temperature change of the display module over time was simulated under room temperature conditions, and the temperature rise curve of the display module under room temperature conditions was obtained.

[0059] By simulating the chromaticity values ​​of the display module at different temperatures, a first relationship curve between the temperature and chromaticity values ​​of the display module is obtained.

[0060] The type and driving method of the compensation light source are determined based on the maximum chromaticity change value, and a second relationship curve between the chromaticity value of the display module and the current of the compensation light source is obtained.

[0061] Determine the pre-correction compensation driving function based on the first relationship curve and the second relationship curve;

[0062] The compensation driving function before correction is modified based on the measured data to obtain the compensation driving function corresponding to the room temperature environment.

[0063] Optionally, the backlight module further includes a temperature monitoring unit;

[0064] Before the main drive module selects the compensation drive function corresponding to the current ambient temperature during the compensation period, the method further includes:

[0065] During the compensation period, the temperature monitoring unit collects the ambient temperature and transmits the ambient temperature information to the main drive module.

[0066] The main drive module acquires the ambient temperature information.

[0067] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0068] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0069] Figure 1 and Figure 2 The VT curves of two liquid crystal displays are shown schematically.

[0070] Figure 3 A schematic diagram of a backlight module structure is shown.

[0071] Figure 4 The diagram schematically illustrates the simulated chromaticity changes of a red light source, a green light source, and a blue light source superimposed on the original backlight source.

[0072] Figure 5 The temperature rise curves of a light-emitting diode under different driving currents are schematically shown.

[0073] Figure 6 The diagram illustrates the chromaticity variation over time of a white point with chromatic coordinates (x, y) driven at 80 mA.

[0074] Figure 7 The normalized spectrum of a primary backlight is schematically shown.

[0075] Figure 8 The normalized spectrum of an R, G, B monochrome LED as a compensation light source is schematically shown.

[0076] Figure 9 A schematic diagram illustrates the chromaticity variation over time with adjusted chromaticity coordinates x and y when driven at 80 mA.

[0077] Figure 10-11 The schematic diagrams of two backlight modules are shown.

[0078] Figure 12 A schematic diagram illustrating the distribution of a white light source and a compensation light source is shown.

[0079] Figure 13 A schematic diagram of a driving method for a backlight module is shown.

[0080] Figure 14 A schematic diagram of the structure of a display module is shown.

[0081] Figure 15 A schematic diagram of another backlight module driving method is shown.

[0082] Figure 16 A flowchart illustrating the establishment of a compensation driving function is shown schematically. Specific Implementation

[0084] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0085] In the embodiments of this application, the terms "first," "second," etc., are used to distinguish identical or similar items with substantially the same function and effect, solely for the purpose of clearly describing the technical solutions of the embodiments of this application, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Furthermore, "multiple" means two or more, unless otherwise explicitly defined.

[0086] Color shifts caused by temperature changes mainly originate from two sources: the backlight module and the panel itself. After the backlight is turned on, the LED strips, as the primary heat source, begin to generate heat, and the ambient temperature around the LEDs gradually rises. Due to the characteristics of LEDs, their color performance varies under different ambient temperatures. The panel itself generates limited heat after being lit, resulting in no significant temperature rise. However, with a well-dissipated backlight module, the temperature rise of the backlight will eventually lead to a rise in the panel's temperature; that is, the panel surface temperature will increase as the backlight temperature rises. Simultaneously, the heat generated by components on the PCB (Printed Circuit Board) will further increase the panel's temperature rise through heat conduction. LEDs, as heat sources, heat up extremely quickly, reaching near-thermal equilibrium temperatures in a short time. Therefore, their impact on the overall process is relatively small, and their color performance can be considered relatively stable. Taking an 18.4-inch display as an example, when powered on at room temperature (25℃), the temperature of the back panel LED strip side is approximately 49~50℃ after the temperature stabilizes, and the surface temperature of the panel center is approximately 45℃. There is a significant difference in the optical performance of the liquid crystal during the initial power-on and after the temperature rise. Specifically, the white point color coordinates are (0.3265, 0.3135) at 1 minute, while after 60 minutes the white point color coordinates change to (0.3216, 0.3049), corresponding to a change in the module color temperature from 5816K to 6140K, indicating white point drift.

[0087] Regardless of whether it is a VA (Vertical Alignment) type or an ADS (Advanced Super Dimension Switch) type display, the optical properties of its liquid crystal will change at different temperatures. That is, the VT curve and Vop will have different performance at different temperatures, which will affect optical brightness and color. Figure 1 The diagram shows three VT curves representing the relationship between light transmittance (Tran) and voltage (Voltage) for a VA-type display. Curves B1, B2, and B3 correspond to 25℃, 40℃, and 50℃, respectively. Figure 2This is a simulation of three VT curves representing the relationship between light transmittance (Tran) and voltage (Voltage) for an ADS-type display. Curves C1, C2, and C3 correspond to 25℃, 40℃, and 50℃, respectively. (Refer to the reference figure.) Figure 2 As shown, the light transmittance of a liquid crystal display varies at different temperatures. Because the transmittance of light varies for different wavelengths, the proportions of R (red), G (green), and B (blue) components in white light change at different temperatures, thus causing a change in color temperature.

[0088] In high-brightness products, due to severe heat generation, the entire body will experience a relatively high temperature rise from initial power-on to stable operation. Before thermal equilibrium is reached, the color temperature of the image under white screen will change significantly, resulting in color shift.

[0089] Based on the above, embodiments of this application provide a backlight module applied to a display module; see reference. Figure 3 As shown, the backlight module 100 includes: a backlight source 1 and a backlight driving unit 2; the backlight source 1 includes: a white light source 11 and a compensation light source 12, the light emission wavelength range of the white light source is a first wavelength range, the light emission wavelength range of the compensation light source is a second wavelength range, and the second wavelength range is located within the first wavelength range; the backlight driving unit 2 includes: a main driving module 21 and a compensation driving module 22.

[0090] The main drive module is electrically connected to both the white light source and the compensation drive module, and is configured to: during the compensation period, select a compensation drive function corresponding to the current ambient temperature, where the compensation period refers to the time from the initial startup of the display module to the thermal equilibrium time, and the compensation drive function includes the correspondence between the drive current of the compensation light source and the ambient temperature; and provide a compensation control signal to the compensation drive module according to the selected compensation drive function.

[0091] The compensation drive module is configured to acquire and provide a drive signal to the compensation light source based on the compensation control signal.

[0092] The compensation light source is configured to acquire a driving signal and emit light under the drive of the driving signal, so that the change value of the white point color coordinate of the display module during the compensation period is within a preset range.

[0093] The aforementioned backlight module can be either side-lit or direct-lit, without limitation. The side-lit backlight module further includes a light guide plate, with the backlight source positioned on one side of the light guide plate. In this case, the white light source and the compensation light source can be positioned on opposite sides of the light guide plate; alternatively, the white light source and the compensation light source can be positioned on the same side of the light guide plate; other configurations are also possible, without limitation. The direct-lit backlight module further includes a diffuser plate and a reflector, with the backlight source positioned between the diffuser plate and the reflector. In this case, the white light source and the compensation light source are positioned between the diffuser plate and the reflector, with the compensation light source positioned around the periphery of the white light source.

[0094] The aforementioned compensation light source may include a monochromatic light source, such as a blue light source, a red light source, a green light source, or a yellow light source, etc.; or, the aforementioned compensation light source may also include a dual-color light source, such as a blue light source and a red light source, or of course, other two colors of light source; or, the aforementioned compensation light source may also include a tri-color light source, such as a blue light source, a red light source, and a green light source, without limitation, and the specific determination depends on the actual product.

[0095] The specific structure of the main drive module and the compensation drive module is not limited. For example, the main drive module may include a SOC (System on Chip), and the compensation drive module may include a compensation drive chip. The type of the compensation drive chip may include a microcontroller, an ARM (Advanced RISC Machines) chip, or an FPGA (Field Programmable Gate Array) chip, etc. The specific type can be determined according to the actual design requirements.

[0096] The aforementioned main drive module can also be configured to control the white light source to emit light; during the compensation period, both the compensation light source and the white light source emit light, and the compensation light source can play a role in color temperature compensation, thereby greatly improving the color shift problem of the display module during the period from the initial startup time to the thermal equilibrium time.

[0097] The specific form of the aforementioned compensation drive function is not limited, as long as it includes the correspondence between the drive current of the compensation light source and the ambient temperature. This compensation drive function can be preset in the main drive module.

[0098] The aforementioned compensation period refers to the time from the initial startup moment to the thermal equilibrium moment of the display module. The initial startup moment includes the power-on moment of the display module, and the thermal equilibrium moment refers to the moment when the display module reaches thermal equilibrium. Thermal equilibrium refers to the state where the internal temperature of an object in contact with the outside world is uniform and equal to the external temperature. At thermal equilibrium, there is no heat exchange between the parts of the object or between the object and its external environment.

[0099] According to the principles of colorimetry, in the CIE1931 XYZ and CIE1964 XYZ standard colorimetric systems, the XYZ tristimulus values ​​of a light source can be obtained by integrating the intensity of the light source with the spectral tristimulus values ​​across the entire spectrum. In colorimetry, the same color temperature can correspond to multiple color coordinates, and the color temperature calculated from the same color coordinate is fixed. Therefore, the color temperature of the white screen can be kept stable by ensuring the stability of the white point color coordinates. The change in the white point color coordinates (x, y) of the above display module during the compensation period refers to the change in x and y. The preset range can be preset according to actual needs. Within this preset range, the change in the white point color coordinates is within an acceptable range, and the color temperature of the white screen is stable. The specific formula for calculating the color temperature (CCT) using the white point color coordinates (x, y) is as follows:

[0100]

[0101] In related technologies, display modules experience color temperature changes in the white screen during the period from power-on to stable operation (i.e., thermal equilibrium). These color temperature or chromaticity changes in the white screen are due to variations in the proportions of different colors of light transmitted. In this application, by setting a compensation light source to compensate for the corresponding chromaticity of light in the white light source, the change in the proportion of corresponding chromaticity light caused by temperature variations is significantly reduced. This ensures that the proportions of different colors of light remain stable, greatly improving the chromaticity shift problem of the display module, enhancing product quality, and facilitating performance optimization for high-brightness products.

[0102] Since the white point color coordinates of the display module change over time during the compensation period, the efficiency (or luminous intensity) of the compensation light source also changes over time. Optionally, the efficiency η of the compensation light source satisfies:

[0103]

[0104] Where t represents time. To display the thermal equilibrium time of the module, A is the module influence factor.

[0105] The above Similar to the compensation period, the function of the working efficiency η of the above-mentioned compensation light source can also be other functions, depending on the corresponding structure.

[0106] The aforementioned module influence factor A is a function related to time t, and the specific functional relationship varies depending on the structural design. The aforementioned compensation light source operates at 100% maximum efficiency when the display module is initially started, and gradually decreases over time. When thermal equilibrium is reached, the compensation light source stops working.

[0107] Optionally, for ease of implementation, the compensation light source may include a blue light source; or, the compensation light source may include a blue light source and a red light source; or, the compensation light source may include a red light source, a green light source, and a blue light source; the specific choice can be made according to actual needs. Figure 4 To simulate the chromaticity changes of red, green, and blue light sources respectively, the original backlight source's luminous intensity is superimposed onto it. The original backlight source's luminous intensity is set at 100% as a baseline. 1%B, 1%R, and 1%G represent 1% luminous intensity of the blue, red, and green light sources, respectively. The meanings of the other values ​​are as described above and will not be repeated here. (Reference) Figure 4 As shown, a blue light source can decrease the x-coordinate and y-coordinate, a red light source can increase the x-coordinate and decrease the y-coordinate, and a green light source can decrease the x-coordinate and increase the y-coordinate.

[0108] In one or more embodiments, the compensation light source includes a blue light source, and compensation is performed using a monochromatic light source. This structure is simple and low-cost. The white point color coordinates (x, y) of the display module when both the white light source and the compensation light source are activated during the compensation period, and the white point color coordinates (x0, y0) of the display module when the white light source is activated but the compensation light source is not activated during the compensation period, satisfy the following:

[0109]

[0110] in, The intensity ratio of the blue light source to the white light source is given. The influence factor of blue light on the x-color coordinate. The influence factor of blue light on the y-coordinate.

[0111] To further ensure the compensation effect, through extensive simulations and field measurements, it was found that: 0≤ ≤10%; -0.08≤ ≤-0.01; -0.2≤ ≤-0.07.

[0112] In one or more embodiments, the compensation light source includes a blue light source and a red light source; using a dual-color light source for compensation provides greater flexibility and wider applicability. The white point color coordinates (x, y) of the display module when both the white light source and the compensation light source are activated during the compensation period, and the white point color coordinates (x0, y0) of the display module when the white light source is activated but the compensation light source is not activated during the compensation period, satisfy the following:

[0113]

[0114] in, , These are the intensity ratios of the red light source and the blue light source relative to the white light source, respectively. , These are the influence factors of red light and blue light on the x-color coordinate, respectively. , These are the influence factors of red light and blue light on the y-coordinate, respectively.

[0115] To further ensure the compensation effect, extensive simulations and field measurements were conducted, and the following results were obtained:

[0116] 0≤ ≤10%, 0≤ ≤10%; -0.08≤ ≤-0.01, 0.07≤ ≤0.2; -0.2≤ ≤-0.07, -0.012≤ ≤-0.005.

[0117] In one or more embodiments, the compensation light source includes a red light source, a green light source, and a blue light source; compensation is performed using a three-color light source. The white point color coordinates (x, y) of the display module when both the white light source and the compensation light source are activated during the compensation period, and the white point color coordinates (x0, y0) of the display module when the white light source is activated but the compensation light source is not activated during the compensation period, satisfy the following:

[0118]

[0119] in, 、 、 These are the intensity ratios of the red light source, the green light source, and the blue light source relative to the white light source, respectively. 、 、 These are the influence factors of red, green, and blue light on the x-color coordinate, respectively. , , These are the influence factors of red light, green light, and blue light on the y-coordinate, respectively.

[0120] To further ensure the compensation effect, extensive simulations and field measurements were conducted, and the following results were obtained:

[0121] 0≤ ≤10%, 0≤ ≤10%, 0≤ ≤10%; 0.07≤ ≤0.2, -0.2≤ ≤0.2、-0.08≤ ≤-0.01; -0.012≤ ≤-0.005, 0.15≤ ≤0.3、-0.2≤ ≤-0.07.

[0122] The compensation effect is illustrated using an 18.4-inch broadcast product as an example. The temperature rise curves of the LED under different drive currents are shown below. Figure 5 As shown, the chromaticity change curve of the white point at chromatic coordinates (x, y) over time when driven by 80mA is as follows: Figure 6 As shown, without compensation, refer to Figure 6 As shown, the white point color coordinates are (0.3265, 0.3135) at startup, corresponding to a color temperature of 5816K; when thermal equilibrium is reached, the white point color coordinates are (0.3209, 0.3039), corresponding to a color temperature of 6191K. That is, when the color temperature decreases from 5816K to 6191K, a color shift phenomenon occurs. Figure 5 The diagram shows four temperature rise curves. Curves A1, A2, A3, and A4 represent the temperature rise curves under drive currents of 80mA, 75mA, 70mA, 80mA, and 65mA, respectively. The horizontal axis represents time in minutes, and the vertical axis represents temperature in degrees Celsius. Figure 6 In the diagram, the chromaticity curves of x and y coordinates under 80mA drive are labeled Wx1 and Wy1, respectively. The horizontal axis represents time in minutes, and the vertical axis represents the chromaticity coordinates without units.

[0123] The normalized spectrum of the original backlight of this product is as follows: Figure 7 As shown, R, G, and B monochromatic LEDs are used as compensation light sources, and their normalized spectra are as follows. Figure 8 As shown. Figure 7 and Figure 8 In the graph, the horizontal axis represents wavelength in nanometers; the vertical axis represents normalized relative light intensity, which is dimensionless. Figure 4 It is known that blue light sources can decrease both the x and y color coordinates, red light sources can increase the x color coordinate and decrease the y color coordinate, and green light sources can decrease the x color coordinate and increase the y color coordinate. Therefore, 6-7% blue LEDs can be used for compensation. Alternatively, red and blue LEDs can be used for color temperature adjustment, as described above. Figure 9 As shown, after compensation, the initial white point color coordinates are (0.3188, 0.3031), corresponding to a color temperature of 6331K; upon reaching thermal equilibrium, the white point color coordinates are (0.3201, 0.3039), corresponding to a color temperature of 6242K. Throughout the compensation phase, the x and y color coordinate variations are within ±0.002, consistent with the variation range of conventional LCD modules, indicating the effectiveness of this control method. Figure 9In the diagram, the chromaticity curves of the adjusted chromaticity coordinates x and y under 80mA drive are labeled Wx1 and Wy1, respectively. The horizontal axis represents time in minutes, and the vertical axis represents the chromaticity coordinates without a unit.

[0124] To reduce size and facilitate weight reduction, the aforementioned backlight module can be configured as a side-lit backlight module; alternatively, refer to... Figure 10 As shown, the backlight module also includes a light guide plate 13, with a white light source 11 and a compensation light source 12 positioned on opposite sides of the light guide plate 13. The white light source and the compensation light source may each include multiple light-emitting diodes; the number is not limited and can be selected according to actual needs.

[0125] To improve the light emission effect and maximize the brightness of the backlight, the aforementioned backlight module can be configured as a direct-lit backlight module; alternatively, refer to... Figure 11 and Figure 12 As shown, the backlight module also includes a diffuser plate 14 and a reflector 15. A white light source 11 and a compensation light source 12 are disposed between the diffuser plate 14 and the reflector 15, and the compensation light source 12 is disposed around the white light source 11. Figure 12 The illustration uses an example of a compensating light source orbiting a white light source. Of course, the compensating light source can also be positioned to one or both sides of the white light source; this is not a limitation. Furthermore, the number of orbits the compensating light source makes around the white light source is not limited. Figure 12 The illustration is based on two circles.

[0126] Optionally, the white light source includes multiple white light emitting units, and the compensation light source includes multiple compensation emitting units. The number of compensation emitting units is less than the number of white light emitting units, thereby saving the number of emitting units and reducing costs.

[0127] The white light emitting unit can be a white light emitting diode, and the compensation emitting unit can be a compensation emitting diode. For example, when the compensation light source includes a blue light source, the compensation emitting unit can include a blue light emitting diode; when the compensation light source includes both a blue light source and a red light source, the compensation emitting unit can include both a blue light emitting diode and a red light emitting diode; when the compensation light source includes a red light source, a green light source, and a blue light source, the compensation emitting unit can include a blue light emitting diode, a red light emitting diode, and a green light emitting diode.

[0128] Optional, see reference Figure 3 As shown, the backlight module also includes a temperature monitoring unit 3, which is electrically connected to the main drive module 21.

[0129] The temperature monitoring unit is configured to collect the ambient temperature during the compensation period and transmit the ambient temperature information to the main drive module; the main drive module is also configured to acquire the ambient temperature information.

[0130] This application uses a temperature monitoring unit to collect ambient temperature, which is easy to implement and has a simple structure. The aforementioned temperature monitoring unit may include a temperature sensor, but it can also be other temperature detection devices, which are not limited here.

[0131] The temperature of the entire product will increase after prolonged operation, especially in high-brightness products. To ensure the reliability of the entire product and the stability of display color, temperature control is necessary. Optional, refer to... Figure 3 As shown, the backlight module also includes a heat dissipation unit 4, which is electrically connected to the main drive module 21.

[0132] The main drive module is also configured to transmit a first control signal to the heat dissipation unit when the ambient temperature is higher than a first set temperature; the first set temperature is lower than the thermal equilibrium temperature of the display module.

[0133] The heat dissipation unit is configured to either activate or increase its heat dissipation power based on the first control signal transmitted from the main drive module.

[0134] The specific value of the first set temperature needs to be determined based on the actual product. For example, if the thermal equilibrium temperature of the display module at room temperature (25°C) is 50°C, then the first set temperature can be set to 48°C to ensure reliable operation under different ambient temperatures.

[0135] It should be noted that the above-mentioned heat dissipation unit can run continuously and increase the heat dissipation power under the control of the first control signal. If the heat dissipation unit includes a fan, the fan speed can be increased to increase the heat dissipation power. Alternatively, the heat dissipation unit can be turned on under the control of the first control signal, that is, it will only be turned on when the ambient temperature is higher than the first set temperature, so as to save the power of the whole machine.

[0136] To reduce the overall operating power, the main drive module is optionally configured to transmit a second control signal to the heat dissipation unit when the ambient temperature is lower than the second set temperature; the second set temperature is lower than the first set temperature.

[0137] The heat dissipation unit is configured to shut down or reduce its heat dissipation power based on a second control signal transmitted from the main drive module.

[0138] The specific value of the second set temperature needs to be determined based on the actual product. For example, if the thermal equilibrium temperature of the display module at room temperature (25°C) is 50°C, then the first set temperature can be set to 48°C, and the second set temperature can be set to 45°C.

[0139] Under the control of the first control signal, the aforementioned heat dissipation unit can reduce its heat dissipation power. If the heat dissipation unit includes a fan, its speed can be reduced to increase its heat dissipation power. Alternatively, the heat dissipation unit can be shut down under the control of the second control signal, i.e., it will stop operating when the ambient temperature is lower than a second set temperature, thereby saving overall power consumption.

[0140] Taking a heat dissipation unit (including a fan), a temperature monitoring unit (including a temperature sensor), and a main drive module (including a System on Chip) as an example, the driving relationship is explained. (Reference) Figure 13 As shown, the temperature sensor collects the ambient temperature and sends the ambient temperature information to the SOC; the SOC receives the ambient temperature information and makes a judgment and comparison; when the ambient temperature exceeds the first set temperature, it sends a first control signal to the fan; after receiving the first control signal, the fan turns on or increases its speed; when the ambient temperature is lower than the second set temperature, it sends a second control signal to the fan; after receiving the second control signal, the fan turns off or decreases its speed.

[0141] Optionally, the preset range is -0.002 to +0.002. The change value of the white point color coordinate of the display module during the compensation period is within this preset range, which is consistent with the change range of conventional LCD display modules, ensuring the stability of color and picture effect from the moment of power-on to stable operation.

[0142] Optionally, to broaden the product's applicability, the main drive module is also configured to: preset multiple compensation drive functions, each corresponding to a different ambient temperature.

[0143] Since the temperature rise performance varies under different ambient temperatures, different compensation driving functions need to be designed for different ambient temperatures to ensure that the backlight module can achieve color compensation under different ambient temperatures.

[0144] Optionally, the ambient temperatures corresponding to multiple compensation drive functions can be sorted in ascending order, with the absolute value of the difference between adjacent ambient temperatures ranging from 3 to 7°C. For example, a measurement can be performed every 5°C. It should be noted that if the actual ambient temperature differs from the temperature corresponding to the preset compensation drive function—for example, if the actual ambient temperature is 34°C, but the temperatures corresponding to multiple compensation drive functions are 25°C, 30°C, 35°C, etc.—then the compensation drive function corresponding to 35°C, which is closest to 34°C, will be used for compensation.

[0145] An embodiment of this application also provides a display module, see reference. Figure 14 As shown, the display module includes a display panel 5 and the aforementioned backlight module 100, with the backlight module 100 disposed on the backlight side of the display panel 5.

[0146] The aforementioned backlight module is configured to provide backlight to the display panel. Figure 5 The image shows an edge-lit backlight module for illustration purposes; however, edge-lit backlight modules can also include other structures. Figure 5 The white light source 11, the compensation light source 12, and the light guide plate 13 are only schematically illustrated. The specific structure of the display panel is not limited; please refer to [reference needed]. Figure 5 As shown, the display panel may include an array substrate 51 and a color filter substrate 52 arranged opposite to each other. Of course, it may also include other structures, which will not be described in detail here. For details, please refer to the relevant technology.

[0147] The type of the aforementioned display module is not limited. It can be a TN (Twisted Nematic) type, VA (Vertical Alignment) type, IPS (In-Plane Switching) type, or ADS (Advanced Super Dimension Switch) type liquid crystal display device, as well as any product or component with display function, such as televisions, digital cameras, mobile phones, and tablet computers, which include these display devices.

[0148] Embodiments of this application also provide a driving method for a backlight module as described above, wherein the backlight module is applied to a display module, and the driving method includes:

[0149] S1. During the compensation period, the main drive module selects a compensation drive function corresponding to the current ambient temperature. The compensation period refers to the time from the initial startup of the display module to the thermal equilibrium time. The compensation drive function includes the correspondence between the drive current of the compensation light source and the ambient temperature.

[0150] S2. The main drive module provides compensation control signals to the compensation drive module according to the selected compensation drive function.

[0151] S3. The compensation drive module acquires and provides a drive signal to the compensation light source based on the compensation control signal.

[0152] S4. The compensation light source obtains the driving signal and emits light under the drive of the driving signal, so that the change value of the white point color coordinate of the display module during the compensation period is within the preset range.

[0153] The relevant descriptions of each component in the above steps can be found in the aforementioned embodiments, and will not be repeated here.

[0154] By performing steps S1-S4 above, the corresponding chromaticity of light in the white light source can be compensated by the compensation light source during the compensation stage. This significantly reduces the change in the proportion of light of the corresponding chromaticity caused by temperature variations, thereby ensuring that the proportion of different colors of light remains stable. This greatly improves the chromaticity shift problem of the display module, enhances product quality, and is beneficial for optimizing the performance of high-brightness products. This method is simple to implement and highly operable.

[0155] Taking a compensation light source including a compensation LED, a temperature monitoring unit that may include a temperature sensor, a main driving module that includes a System on Chip (SOC), and a compensation driving module that includes an LED driver as an example, the driving method is explained. (Reference) Figure 15 As shown, the driving method includes:

[0156] S100, power on and start.

[0157] S101, Temperature sensor acquires ambient temperature.

[0158] S102 and SOC select a specific compensation driving function based on the ambient temperature.

[0159] S103, LED Driver drives the LED according to the compensation drive function.

[0160] S104, red, green, and blue compensated LED light emission.

[0161] Optionally, before the main drive module selects the compensation drive function corresponding to the current ambient temperature during the compensation period in S1, the above driving method further includes:

[0162] S10. The main drive module has multiple preset compensation drive functions, each corresponding to a different ambient temperature.

[0163] It should be noted that step S10 is executed before the product leaves the factory, and multiple compensation drive functions are pre-set in the products.

[0164] Further optionally, S10 and the main drive module pre-set several compensation drive functions, including:

[0165] S101. Establish multiple compensation driving functions.

[0166] S102. Integrate multiple compensation drive functions into the main drive module.

[0167] Further optional, S101, establishing the compensation driving function includes:

[0168] S1011. Simulate the temperature change of the display module over time under room temperature conditions to obtain the temperature rise curve of the display module under room temperature conditions.

[0169] In step S1011, the time required for the temperature to rise from the initial start-up to thermal equilibrium (i.e., the thermal equilibrium time) can be obtained. ).

[0170] S1012. Simulate the chromaticity values ​​of the display module at different temperatures to obtain the first relationship curve between the temperature and chromaticity values ​​of the display module.

[0171] S1013. Determine the type and driving method of the compensation light source based on the maximum chromaticity change value, and obtain the second relationship curve between the chromaticity value of the display module and the current of the compensation light source.

[0172] The aforementioned maximum chromaticity change value refers to the difference between the maximum and minimum values ​​of the white point chromaticity coordinate x during the period from initial startup to thermal equilibrium, and the difference between the maximum and minimum values ​​of the chromaticity coordinate y during the period from initial startup to thermal equilibrium.

[0173] The type of compensation light source may include a monochromatic light source, such as a blue light source, a red light source, or a green light source; or, the compensation light source may also include a dual-color light source, such as a blue light source and a red light source; or, the compensation light source may also include a tri-color light source, such as a blue light source, a red light source, and a green light source.

[0174] The driving method described above can be either PWM or DC driving; there is no specific limitation here. PWM driving controls the screen to blink alternately at a certain frequency, utilizing the persistence of vision to achieve a continuous display effect. Simply put, PWM dimming involves a continuous alternation of on / off cycles, changing the LED brightness by varying the alternation time. DC driving controls the LED display brightness by adjusting the LED voltage or current, i.e., by changing the power.

[0175] S1014. Determine the compensation driving function before correction based on the first relationship curve and the second relationship curve.

[0176] The specific methods for determining this can be found in relevant technologies, and will not be elaborated here.

[0177] S1015. Based on the measured data, the compensation driving function before correction is corrected to obtain the compensation driving function corresponding to the room temperature environment.

[0178] It should be noted that after executing steps S1011-S1015, only the compensation driving function corresponding to the room temperature environment can be obtained; the steps for establishing the compensation driving function corresponding to other ambient temperatures can be referred to steps S1011-S1015, and will not be elaborated here. Figure 16For a simplified flowchart of the complete setup steps of step S101 above, refer to... Figure 16 As shown, by executing steps S200-S204, multiple compensation drive functions can be placed in the main drive module's board.

[0179] In one or more embodiments, the backlight module further includes a temperature monitoring unit.

[0180] Before the main drive module selects the compensation drive function corresponding to the current ambient temperature during the compensation period in S1, this method also includes:

[0181] S5. During the compensation period, the temperature monitoring unit collects the ambient temperature and transmits the ambient temperature information to the main drive module.

[0182] The aforementioned temperature monitoring unit may include a temperature sensor. It should be noted that, when the display module includes a heat dissipation unit, the temperature monitoring unit can continue to collect ambient temperature data outside the compensation period, so that the main drive module can control the heat dissipation power of the heat dissipation unit. The method and frequency of temperature monitoring unit data collection outside the compensation period are not limited; for example, it can collect data in real time or at regular intervals, depending on the specific circumstances.

[0183] S6. The main drive module obtains ambient temperature information.

[0184] By executing steps S5-S6, the main drive module can obtain the current ambient temperature.

[0185] The terms "an embodiment," "embodiment," or "one or more embodiments" as used herein mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this application. Furthermore, please note that the examples of the phrase "in one embodiment" do not necessarily all refer to the same embodiment.

[0186] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A backlight module, wherein, Applied to display modules; The backlight module includes: a backlight source and a backlight driving unit; the backlight source includes: a white light source and a compensation light source, the white light source has an emission wavelength range of a first wavelength range, and the compensation light source has an emission wavelength range of a second wavelength range, the second wavelength range being located within the first wavelength range; the backlight driving unit includes: a main driving module and a compensation driving module; The main driving module is electrically connected to both the white light source and the compensation driving module, and is configured to: during the compensation period, select a compensation driving function corresponding to the current ambient temperature, wherein the compensation period refers to the time from the initial startup of the display module to the thermal equilibrium time, and the compensation driving function includes the correspondence between the driving current of the compensation light source and the ambient temperature; and provide a compensation control signal to the compensation driving module according to the selected compensation driving function. The compensation driving module is configured to: acquire and provide a driving signal to the compensation light source according to the compensation control signal; The compensation light source is configured to: acquire the driving signal and emit light under the drive of the driving signal, so that the change value of the white point color coordinate of the display module during the compensation period is within a preset range; Wherein, the working efficiency η of the compensation light source satisfies: Where t represents time. The thermal equilibrium time of the display module is given by , and A is the module influence factor.

2. The backlight module according to claim 1, wherein, The compensation light source includes a blue light source; Alternatively, the compensation light source may include a blue light source and a red light source; Alternatively, the compensation light source may include a red light source, a green light source, and a blue light source.

3. The backlight module according to claim 1, wherein, The compensation light source includes a blue light source; The white point color coordinates (x, y) of the display module when the white light source and the compensation light source are activated during the compensation period, and the white point color coordinates (x0, y0) of the display module when the white light source is activated but the compensation light source is not activated during the compensation period, satisfy the following: in, The intensity ratio of the blue light source to the white light source is given. The influence factor of blue light on the x-color coordinate. The influence factor of blue light on the y-coordinate.

4. The backlight module according to claim 3, wherein, 0≤ ≤10%；-0.08≤ ≤-0.01；-0.2≤ ≤-0.07。 5. The backlight module according to claim 1, wherein, The compensation light source includes a blue light source and a red light source; The white point color coordinates (x, y) of the display module when the white light source and the compensation light source are activated during the compensation period, and the white point color coordinates (x0, y0) of the display module when the white light source is activated but the compensation light source is not activated during the compensation period, satisfy the following: in, , These are the intensity ratios of the red light source and the blue light source relative to the white light source, respectively. , These are the influence factors of red light and blue light on the x-color coordinate, respectively. , These are the influence factors of red light and blue light on the y-coordinate, respectively.

6. The backlight module according to claim 5, wherein, 0≤ ≤10%、0≤ ≤10%； -0.08≤ ≤-0.01、0.07≤ ≤0.2； -0.2≤ ≤-0.07、-0.012≤ ≤-0.005。 7. The backlight module according to claim 1, wherein, The compensation light source includes a red light source, a green light source, and a blue light source; The white point color coordinates (x, y) of the display module when the white light source and the compensation light source are activated during the compensation period, and the white point color coordinates (x0, y0) of the display module when the white light source is activated but the compensation light source is not activated during the compensation period, satisfy the following: in, , , These are the intensity ratios of the red light source, the green light source, and the blue light source relative to the white light source, respectively. , , These are the influence factors of red, green, and blue light on the x-color coordinate, respectively. , , These are the influence factors of red light, green light, and blue light on the y-coordinate, respectively.

8. The backlight module according to claim 7, wherein, 0≤ ≤10%、0≤ ≤10%、0≤ ≤10%； 0.07≤ ≤0.2、-0.2≤ ≤0.2、-0.08≤ ≤-0.01； -0.012≤ ≤-0.005、0.15≤ ≤0.3、-0.2≤ ≤-0.07。 9. The backlight module according to claim 1, wherein, The backlight module also includes a light guide plate, with the white light source and the compensation light source positioned on opposite sides of the light guide plate.

10. The backlight module according to claim 1, wherein, The backlight module also includes a diffuser plate and a reflector sheet. The white light source and the compensation light source are disposed between the diffuser plate and the reflector sheet, and the compensation light source is disposed around the white light source.

11. The backlight module according to claim 1, wherein, The white light source includes multiple white light emitting units, and the compensation light source includes multiple compensation emitting units, wherein the number of compensation emitting units is less than the number of white light emitting units.

12. The backlight module according to claim 1, wherein, The backlight module also includes a temperature monitoring unit, which is electrically connected to the main drive module. The temperature monitoring unit is configured to: collect the ambient temperature and transmit the ambient temperature information to the main drive module during the compensation period; the main drive module is also configured to: acquire the ambient temperature information.

13. The backlight module according to claim 12, wherein, The backlight module also includes a heat dissipation unit, which is electrically connected to the main drive module. The main drive module is further configured to transmit a first control signal to the heat dissipation unit when the ambient temperature is higher than a first set temperature; the first set temperature is lower than the thermal equilibrium temperature of the display module. The heat dissipation unit is configured to activate or increase its heat dissipation power according to the first control signal transmitted by the main drive module.

14. The backlight module according to claim 13, wherein, The main drive module is further configured to transmit a second control signal to the heat dissipation unit when the ambient temperature is lower than a second set temperature; the second set temperature is lower than the first set temperature. The heat dissipation unit is configured to shut down or reduce its heat dissipation power according to the second control signal transmitted by the main drive module.

15. The backlight module according to claim 1, wherein, The preset range is -0.002 to +0.

002.

16. The backlight module according to claim 1, wherein, The main drive module is also configured to: preset multiple compensation drive functions, each of which corresponds to a different ambient temperature.

17. The backlight module according to claim 16, wherein, The ambient temperatures corresponding to the multiple compensation driving functions are sorted in ascending order, and the absolute value range of the difference between adjacent ambient temperatures is 3 to 7°C.

18. A display module, wherein, include: The display panel and the backlight module according to any one of claims 1-17, wherein the backlight module is disposed on the backlight side of the display panel.

19. A driving method for a backlight module as described in any one of claims 1-17, wherein, The backlight module is applied to the display module, and the driving method includes: During the compensation period, the main drive module selects a compensation drive function corresponding to the current ambient temperature based on the current ambient temperature. The compensation period refers to the time from the initial startup time to the thermal equilibrium time of the display module, and the compensation drive function includes the correspondence between the driving current of the compensation light source and the ambient temperature. The main drive module provides a compensation control signal to the compensation drive module according to the selected compensation drive function; The compensation driving module acquires and provides a driving signal to the compensation light source according to the compensation control signal; The compensation light source acquires the driving signal and emits light under the drive of the driving signal, so that the change value of the white point color coordinate of the display module during the compensation period is within a preset range.

20. The method according to claim 19, wherein, Before the main drive module selects the compensation drive function corresponding to the current ambient temperature during the compensation period, the method further includes: The main drive module presets multiple compensation drive functions, each of which corresponds to a different ambient temperature.

21. The method according to claim 20, wherein, The main driving module pre-sets multiple compensation driving functions, including: Establish multiple compensation driving functions; Multiple compensation driving functions are built into the main driving module.

22. The method according to claim 21, wherein, Establishing the compensation driving function includes: The temperature change of the display module over time was simulated under room temperature conditions, and the temperature rise curve of the display module under room temperature conditions was obtained. By simulating the chromaticity values ​​of the display module at different temperatures, a first relationship curve between the temperature and chromaticity values ​​of the display module is obtained. The type and driving method of the compensation light source are determined based on the maximum chromaticity change value, and a second relationship curve between the chromaticity value of the display module and the current of the compensation light source is obtained. Determine the pre-correction compensation driving function based on the first relationship curve and the second relationship curve; The compensation driving function before correction is modified based on the measured data to obtain the compensation driving function corresponding to the room temperature environment.

23. The method according to claim 19, wherein, The backlight module also includes a temperature monitoring unit; Before the main drive module selects the compensation drive function corresponding to the current ambient temperature during the compensation period, the method further includes: During the compensation period, the temperature monitoring unit collects the ambient temperature and transmits the ambient temperature information to the main drive module. The main drive module acquires the ambient temperature information.

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