Backlight Control Circuit

Abstract

The present invention provides a backlight control circuit for driving a surface emitting device. The backlight control circuit includes a drive circuit. The drive circuit generates a plurality of drive currents to drive the surface emitting device such that a plurality of backlight blocks of the surface emitting device generate a plurality of luminance values. Each backlight block includes at least one light source for emitting a light beam. The surface emitting device is divided into at least a first backlight area and a second backlight area. The second backlight area is closer to an edge of the surface emitting device than the first backlight area. A first drive current of the plurality of drive currents drives a light source of the first backlight area. A second drive current of the plurality of drive currents drives a light source of the second backlight area. The second drive current is greater than the first drive current.

Description

[Technical Field]

[0001] The present invention relates to a backlight control circuit, and more particularly to a backlight control circuit that can improve display uniformity. [Background technology]

[0002] With the development of science and technology and industrial progress, various electronic products equipped with liquid crystal displays (LCDs), such as laptops, tablet computers, mobile phones, and televisions, have become an indispensable part of users' lives. Electronic products display images on their displays, allowing users to view them. Because display panels themselves do not emit light, backlight devices are typically used to provide the backlighting required for the display panel to display images. Light-emitting diodes (LEDs), for example, are widely used in backlight devices due to their advantages of low power consumption, long component life, mercury-free operation, a wide color gamut, no lamp warm-up time, and fast response time. However, current backlight devices often suffer from uneven brightness, resulting in dark bands in the corners or edges of the display, and insufficient uniformity. Furthermore, as display devices become larger, the power consumption of backlight devices also increases. One currently common solution is to modify the light source arrangement, for example, by changing the spacing of the light source array to improve uniformity. Another approach is to use light source sorting (binning) technology to arrange light sources at different levels. However, the conventional approach still has the drawback of high input costs for light source assembly and high manufacturing man-hours. Therefore, how to effectively solve the above problems has become an important issue in this technical field. Summary of the Invention

[0003] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a backlight control circuit that can improve the uniformity of the display.

[0004] The present invention provides a backlight control circuit for driving a surface-emitting device, which generates a plurality of drive currents to drive the surface-emitting device, thereby causing a plurality of backlight blocks of the surface-emitting device to generate a plurality of brightness values, each backlight block including at least one light source and equipped with a drive circuit that emits light rays, the surface-emitting device being divided into at least a first backlight area and a second backlight area, the second backlight area being closer to an edge of the surface-emitting device than the first backlight area, a first drive current of the plurality of drive currents being used to drive a light source of a backlight block of the first backlight area, a second drive current of the plurality of drive currents being used to drive a light source of a backlight block of the second backlight area, and the second drive current being greater than the first drive current. [Brief explanation of the drawings]

[0005] [Figure 1] 1 is a schematic diagram of a display device according to an embodiment of the present invention; [Figure 2] 1 is a schematic diagram of a surface emitting device according to an embodiment of the present invention. [Figure 3] FIG. 1 is a schematic diagram of a flow according to an embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram of the uniformity of a backlight block according to an embodiment of the present invention; [Figure 5] FIG. 4 is a schematic diagram of a target uniformity of a backlight block according to an embodiment of the present invention; [Figure 6] 5A and 5B are schematic diagrams illustrating target brightness value calculation according to an embodiment of the present invention. [Figure 7] 10 is a schematic diagram of a curve used in a curve fitting calculation of a surface emitting device having an aspect ratio according to an embodiment of the present invention. [Figure 8] FIG. 4 is a schematic diagram of the adjusted driving current of the backlight block according to the embodiment of the present invention; [Figure 9] FIG. 4 is a schematic diagram of the adjusted driving current of the backlight block according to the embodiment of the present invention; [Figure 10] FIG. 4 is a schematic diagram of the adjusted driving current of the backlight block according to the embodiment of the present invention; [Figure 11] FIG. 4 is a schematic diagram of the adjusted driving current of the backlight block according to the embodiment of the present invention; [Figure 12] FIG. 10 is a schematic diagram of another flow according to an embodiment of the present invention. [Figure 13] 10 is a schematic diagram of another example of a surface emitting device according to an embodiment of the present invention. FIG. [Figure 14] FIG. 4 is a schematic diagram showing the correspondence relationship between backlight blocks and light-emitting blocks according to an embodiment of the present invention. [Figure 15] FIG. 10 is a schematic diagram of yet another flow according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0006] FIG. 1 is a schematic diagram of a display device 1 according to an embodiment of the present invention. The display device 1 includes a display panel 10, a surface-emitting device 20, and a backlight control circuit 30. The display panel 10 may be, but is not limited to, a liquid crystal display (LCD) panel. The display panel 10 is disposed above the surface-emitting device 20. The surface-emitting device 20 provides necessary backlight for the display panel 10. For example, FIG. 2 is a schematic diagram of an embodiment of a surface-emitting device 20 according to the present invention. The surface-emitting device 20 can be divided into a plurality of backlight blocks B. The plurality of backlight blocks of the light-emitting device 20 correspond to the display area of the display panel 10 and provide necessary backlight for the display area of the display panel 10. The backlight blocks arranged along a direction D1 (first direction) may be defined as a block column and may be referred to as a first group. The backlight blocks arranged along a direction D2 (second direction) may be defined as a block row and may be referred to as a second group. The direction D1 and the direction D2 are non-parallel. Each block column and block row includes at least one backlight block. As shown in FIG. 2, the surface light emitting device 20 includes block columns BR1 to BRn and block rows BC1 to BCm. Each block column includes m backlight blocks, and each block row includes n backlight blocks. Each backlight block includes at least one light source for emitting light rays. When the light source is turned on, the emitted light rays are irradiated onto the display panel 10.

[0007] The backlight control circuit 30 is coupled to the surface light-emitting device 20 and drives the surface light-emitting device 20 to provide uniform backlight to the display panel 10. The backlight control circuit 30 includes a processing circuit 302, a measurement circuit 304, and a drive circuit 306. The measurement circuit 304 measures the luminance value of the backlight block of the surface light-emitting device 20. The measurement circuit 304 includes an image sensor (not shown), which may include, but is not limited to, a charge-coupled device (CCD) image sensor or a complementary metal-oxide semiconductor (CMOS) image sensor. The drive circuit 306 generates multiple drive currents, multiple pre-drive currents, or multiple adjusted drive currents to drive the light sources of the backlight block of the surface light-emitting device 20. The drive circuit 306 may be a pulse width modulation circuit. The processing circuit 302 is coupled to the measurement circuit 304 and the drive circuit 306. The processing circuit 302 generates adjustment values corresponding to the plurality of backlight blocks so that the drive circuit 306 generates a plurality of adjusted drive currents based on the adjustment values and the drive currents to drive the plurality of backlight blocks. The display device 1 further includes a display drive circuit (not shown) for controlling the image display operation of the display panel 10.

[0008] 3, the operation method of the display device 1 can be summarized as Flow 3, which is a schematic diagram of Flow 3 according to an embodiment of the present invention. Flow 3 includes the following steps:

[0009] Step S300: Start.

[0010] Step S302: Generate a plurality of driving currents to drive the surface light emitting device, so that a plurality of backlight blocks generate a plurality of luminance values.

[0011] Step S304: Measure multiple luminance values of multiple backlight blocks.

[0012] Step S306: Calculate a plurality of uniformities of the plurality of backlight blocks according to the plurality of brightness values, and set a plurality of target uniformities.

[0013] Step S308: Generate a plurality of adjustment values according to the plurality of uniformities, the plurality of target uniformities, and a plurality of adjustment coefficients corresponding to the plurality of backlight blocks.

[0014] Step S310: Generate a plurality of adjusted driving currents based on the adjustment value and the plurality of driving currents to drive the plurality of backlight blocks.

[0015] Step S312: End.

[0016] According to Flow 3, in step S302, the drive circuit 306 generates multiple drive currents to drive the surface light emitting device 10 so that the multiple backlight blocks of the surface light emitting device 10 generate multiple luminance values. In step S304, the measurement circuit 304 measures multiple luminance values of the multiple backlight blocks of the surface light emitting device 10. For example, the measurement circuit 304 measures a corresponding luminance value for each backlight block. Each backlight block has a corresponding luminance value.

[0017] In step S306, the processing circuit 302 calculates multiple uniformities for the multiple backlight blocks of the surface emitting device 10 from the multiple brightness values and sets multiple target uniformities. The processing circuit 302 calculates the uniformity for each backlight block based on the multiple brightness values corresponding to the multiple backlight blocks measured by the measurement circuit 304. For example, the processing circuit 302 sets a target brightness value for each backlight block and calculates the ratio of the brightness value of each backlight block to the maximum brightness value among the multiple target brightness values to obtain the uniformity for each backlight block. As shown in FIG. 4, taking the surface emitting device 20 having 5×5 backlight blocks as an example, the surface emitting device 20 includes block columns BR1 to BR5 and block rows BC1 to BC5. The processing circuit 302 calculates the uniformity for each backlight block. As shown in FIG. 4, the numbers for each backlight block indicate the uniformity of the backlight block. Here, a partial uniformity greater than 1 means that the brightness value of the backlight block is greater than the maximum brightness value among the multiple target brightness values.

[0018] Further, in step S306, in some embodiments, the processing circuit 302 references a target brightness value table to find the target brightness value corresponding to each backlight block. The target brightness value table may be stored in a storage device (not shown) of the display device 1 in the form of a lookup table. The processing circuit 302 can reference the target brightness value table stored in the storage device to find the target brightness value corresponding to each backlight block. After the target brightness value of each backlight block is set, the processing circuit 302 calculates the target uniformity of each backlight block from the target brightness values corresponding to the multiple backlight blocks. For example, the processing circuit 30 determines the maximum target brightness value among the multiple target brightness values of the multiple backlight blocks of the surface emitting device 10. For each backlight block, the processing circuit 302 calculates the ratio of the target brightness value of each backlight block to the maximum target brightness value among the multiple target brightness values, thereby determining the target uniformity of each backlight block. As shown in FIG. 5, the processing circuit 302 sets and calculates the target uniformity of each backlight block. The number in each backlight block indicates the target uniformity of the backlight block, where the uniformity in the center is equal to 1 and all other uniformities are less than 1, which means that the backlight block is designed to have maximum brightness in the center according to needs, with the brightness gradually decreasing toward the periphery.

[0019] In another embodiment, the processing circuit 302 first determines a target uniformity for a central backlight block of the surface emitting device 20. The central backlight block may be a backlight block located at or near the center of the surface emitting device 20 and located at the boundary between a block column and a block row. The processing circuit 302 determines a target uniformity for backlight blocks located on both edges of a block column including the central backlight block among a plurality of block columns, and calculates and obtains a target luminance value for each backlight block in the block column based on an equation. Next, the processing circuit 302 determines a target uniformity for backlight blocks located on both edges of a block row including the central backlight block among a plurality of block rows, and calculates and obtains a target luminance value for each backlight block in the block row based on the target uniformity of the central backlight block.

[0020] For example, referring to FIG. 6, FIG. 6 is a schematic diagram of target brightness value calculation according to an embodiment of the present invention. Taking a surface emitting device 20 having 5×5 backlight blocks as an example, backlight block B33 is the central backlight block as shown in FIG. 6. Backlight block B33 is located at the boundary between block column BR3 and block row BC3 of the surface emitting device 20. First, the processing circuit 302 obtains the target uniformity of backlight block B33 (the central backlight block) and the target uniformity of backlight blocks (backlight blocks B31 and B35) corresponding to both edges of block column BR3 of backlight block B33. For example, the processing circuit 302 can calculate the target brightness values of backlight blocks B33, B31, and B35 using the target brightness value calculation method based on default target brightness values of backlight blocks B33, B31, and B35. This default target brightness value may be preset. For example, the target uniformity of backlight blocks B33, B31, and B35 may be preset or obtained using a lookup table. The processing circuit 302 may obtain the target uniformity of each backlight block in block row BR3 by performing calculations based on formula F1 and the target uniformity of backlight blocks B33, B31, and B35. For example, the processing circuit 302 may perform curve fitting on the target uniformity of backlight blocks B33, B31, and B35 based on formula F1 to obtain the target uniformity of backlight blocks B32 and B34. As shown in FIG. 6, curve C1 represents the curve of formula F1. In this embodiment, curve C1 is used as the curve of normal distribution formula F1, but is not limited thereto.

[0021] Referring now to FIG. 6 , the processing circuit 302 obtains the target uniformity of the backlight blocks (backlight blocks B13 and B53) corresponding to both edges of the block row BC3 of the backlight block B33, as well as the target uniformity of the backlight block B33 (the central backlight block) obtained in the previous paragraph. For example, the processing circuit 302 performs a curve fitting operation on the target uniformity of the backlight blocks B33, B13, and B53 based on formula F2 to obtain the target uniformity of the backlight blocks B23 and B43. As shown in FIG. 6 , curve C2 represents the curve of formula F2. In this embodiment, curve C2 is used as the curve of the normal distribution formula F2, but is not limited thereto. In this manner, the processing circuit 302 can set the target uniformity of the backlight blocks in the block column BR3 and block row BC3 corresponding to the central backlight block (backlight block B33). Similarly, the processing circuit 302 can set the target uniformity of the backlight blocks in each block column and block row of the surface emitting device 20. Furthermore, the target uniformity of the central backlight block located at the boundary between block column BR3 and block row BC3 can be the same on curve C1 or curve C2. This backlight block can be designed to have the maximum brightness in the middle according to needs, ensuring that the brightness in the surrounding direction has a taper effect according to formulas F1 and F2. If formulas F1 and F2 are normal distributions, the taper effect can be smoothed and not drop sharply.

[0022] When applied to a surface-emitting device 20 having an aspect ratio, a backlight block located at or near the center of the surface-emitting device 20 and at the boundary between a block column and a block row is defined as a central backlight block. The maximum distance between the backlight block closest to an edge of the multiple block columns of the surface-emitting device 20 and the central backlight block is greater than the maximum distance between the backlight block closest to an edge of the multiple block rows of the surface-emitting device 20 and the central backlight block, and the adjustment value corresponding to the backlight block closest to an edge of the multiple block columns is greater than the adjustment value corresponding to the backlight block closest to an edge of the multiple block rows. In other words, the block columns are arranged along the minor axis direction, and the block rows are arranged along the major axis direction. Referring to FIG. 7, FIG. 7 is a schematic diagram of curves C1 and C2 used for curve fitting calculation when an embodiment of the present invention is applied to a surface-emitting device having an aspect ratio. Here, because the number of block rows is greater than the number of block columns, as shown in Figure 7, curve C1 can span a large number of block rows, and the distance between the edge backlight blocks and the central backlight block is long, so there is no need to quickly increase from the low brightness of the edge backlight blocks to the high brightness of the central backlight blocks, and curve C1 can rise from the edge backlight blocks to the central backlight block along a curve with a small curvature (gentle). As shown in Figure 7, curve C2 spans a small number of block columns, and the distance between the edge backlight blocks and the central backlight block is relatively short, so there is a need to quickly increase from the low brightness of the edge backlight blocks to the high brightness of the central backlight block, and curve C2 must rise from the edge backlight blocks to the central backlight block along a curve with a large curvature (steep).

[0023] Therefore, for the surface emitting device 20 having an aspect ratio, first, based on the uniformity of the center backlight block and the edge backlight block in the same block row, a curve C1 with a small curvature (gentle curvature) and a corresponding formula F1 are used to determine the uniformity of the backlight blocks at other positions in the same block row. Next, a curve fitting operation is performed based on the uniformity of the center backlight block and the edge backlight blocks in the same block row to determine the uniformity of the backlight blocks at other positions in the same block row. The result of the curve fitting is a curve C2 with a large curvature (steep curvature). With this design, when the surface emitting device 20 is designed with an aspect ratio of 16:9 or 16:10, the user will experience a relatively gradual change in uniformity in the horizontal major axis direction, making it suitable for applications with a relatively large viewing angle, such as televisions, screens, laptops, and automotive products.

[0024] In step S308, the processing circuit 302 generates a plurality of adjustment values based on the plurality of uniformities, the plurality of target uniformities, and a plurality of adjustment coefficients corresponding to the plurality of backlight blocks. For example, the backlight blocks in each block row correspond to corresponding adjustment coefficients. The plurality of adjustment coefficients may be different. The processing circuit 302 can calculate a plurality of adjustment values corresponding to the plurality of backlight blocks of the surface emitting device 20 based on Equation (1).

number

[0025] Here, Ai,k indicates the adjustment value of the i-th backlight block in the k-th block column (BRk), UTi,k indicates the target uniformity of the i-th backlight block in the k-th block column (BRk), Ui,k indicates the uniformity of the i-th backlight block in the k-th block column (BRk), and Gk indicates the adjustment coefficient corresponding to the k-th block column (BRk), where i = 1 to m, k = 1 to n, and Gk is a real number.

[0026] 4 and 5, adjustment coefficients G1 to G5 correspond to block rows BR1 to BR5. The processing circuit 302 can divide the target uniformity of the backlight blocks in each block row by the uniformity of the backlight blocks to generate a uniformity ratio, and then use the corresponding adjustment coefficient as an index to perform an exponential operation on the uniformity ratio to generate an adjustment value corresponding to the backlight blocks in the block row. For example, taking block row BR1 as an example, the processing circuit 302 can calculate the adjustment value of each backlight block in block row BR1 based on equation (2):

number

[0027] Here, Ai,1 indicates the adjustment value of the i-th backlight block in block row BR1, UTi,1 indicates the target uniformity of the i-th backlight block in block row BR1, Ui,1 indicates the uniformity of the i-th backlight block in block row BR1, and G1 indicates the adjustment coefficient corresponding to block row BR1, where i=1 to m.

[0028] The method by which the backlight blocks in the other block rows BR2 to BR5 generate adjustment values is the same as that for the block row BR1, and therefore will not be described here. In this way, the processing circuit 302 can calculate adjustment values corresponding to all backlight blocks of the surface emitting device 20. Furthermore, because the adjustment coefficient is an exponential, the change in response to the adjustment value is an exponential increase rather than a simple linear increase, and when the uniformity ratio of the backlight block is greater than 1, the adjustment value is increased more drastically, improving the current value of the backlight block and reinforcing areas where brightness is insufficient.

[0029] As for how the value of the adjustment coefficient is determined, as will be described later, with reference to Fig. 6, the adjustment coefficient G3 is based on the curve C1, for example, the adjustment coefficient G3 is the curvature of the curve C1, and for block rows BC1 to BC5, the adjustment coefficient for block row BC3 is the curvature of the curve C2. When the surface light emitting device is rectangular as shown in Fig. 6, the curvatures of the curves C1 and C2 are the same, and when the surface light emitting device is rectangular as shown in Fig. 7, the curvature of the curve C1 on the major axis is small and the curvature of the curve C2 on the minor axis is large.

[0030] The backlight blocks in each block column correspond to corresponding adjustment coefficients. The adjustment coefficients are real numbers. The adjustment coefficients may be different from each other. For example, adjustment coefficient G1 is different from adjustment coefficient G2. A backlight block located at or near the center of the surface light-emitting device 20 and at the boundary between a block column and a block row may be defined as a central backlight block. For example, still referring to FIG. 6, backlight block B33 may be the central backlight block. In this case, when the minimum distance between a backlight block in a first block column among the plurality of block columns of the surface light-emitting device 20 and the central backlight block is smaller than the minimum distance between a backlight block in a second block column among the plurality of block columns of the surface light-emitting device 20 and the central backlight block, the adjustment coefficient of the backlight block corresponding to the first block column among the plurality of block columns is larger than the adjustment coefficient of the backlight block corresponding to the second block column among the plurality of block columns.

[0031] For example, continuing to refer to Figures 4 to 6, an example will be described in which backlight block B33 is the central backlight block, and the minimum distance L1 from block row BR1 to backlight block B33 (i.e., the vertical distance from block row BR1 to backlight block B33) is two backlight blocks. The minimum distance L2 from block row BR2 to backlight block B33 (i.e., the vertical distance from block row BR2 to backlight block B33) is one backlight block. In this case, the adjustment coefficient G2 of the backlight block corresponding to block row BR2 is greater than the adjustment coefficient G1 of the backlight block corresponding to block row BR1.

[0032] 13 is a schematic diagram of another embodiment of a surface emitting device 20 according to the present invention. The surface emitting device 20 includes a light source module 202 and a backlight module 204. The light source module 202 includes a substrate 206 and a plurality of light sources 208 arranged on the substrate 206. The backlight module 204 includes a diffuser 210 and an optical film 212. The light source 208 emits light. For example, the light source 208 may be realized by a light-emitting diode (LED), a miniLED, or any other device capable of emitting light. When the light source 208 is turned on, the emitted light is irradiated onto the display panel 10. Further referring to FIG. 14, the light source module 202 defines a plurality of light-emitting blocks L, each of which includes at least one light source 208. The number of the light-emitting blocks L is equal to or greater than the number of the backlight blocks B. The light source module may be disposed below the backlight module 204. The main purpose of this embodiment of the present invention is to use a smaller adjustment coefficient for light sources 208 closer to the edge, as they have a smaller influence on brightness (the closer the dashed triangular area in FIG. 13 is to the edge, the fewer rays there are), and therefore a slower response, and conversely, to use a larger adjustment coefficient for light sources 208 closer to the center, as they have a larger influence on brightness (the dashed triangular area in FIG. 13 has some overlapping rays in the central region). In this way, the uniformity or brightness of backlight blocks at different positions can be locally fine-tuned based on the actual brightness representation, effectively optimizing the brightness distribution representation of the surface emitting device 20 and significantly improving the problem of brightness unevenness.

[0033] In step S310, the driving circuit 306 generates a plurality of adjusted driving currents based on the plurality of adjustment values and the plurality of driving currents to drive the plurality of backlight blocks. The processing circuit 302 calculates the magnitudes of the plurality of adjusted driving currents based on the adjustment values obtained in step S308 and the plurality of driving currents used in step S302, and causes the driving circuit 306 to generate the plurality of adjusted driving currents to drive the plurality of backlight blocks of the surface emitting device 20. For each backlight block, the driving circuit 306 generates a corresponding adjusted driving current. The adjusted driving current of each backlight block may be the product of the adjustment value corresponding to the backlight block and the driving current corresponding to the backlight block. For example, the adjusted driving current I′ of each backlight block can be expressed as follows:

number

[0034] Here, I′i,k denotes the adjusted driving current of the i-th backlight block in the k-th block column (BRk), Ai,k denotes the adjusted value of the i-th backlight block in the k-th block column (BRk), and Ii,k denotes the original driving current (e.g., the driving current used in step S302) of the i-th backlight block in the k-th block column (BRk), where i=1 to m and k=1 to n.

[0035] As shown in FIG. 13 , the dashed lines represent light ray paths. However, due to the light ray emission angles of the light sources 208 themselves, the closer the backlight blocks are to the interior of the surface-emitting device 20, the more likely the light rays are to overlap, resulting in high brightness. The closer the backlight blocks are to the periphery of the surface-emitting device 20, the more likely the light rays are to be biased to one side, resulting in low brightness. Backlight blocks at the four corners of the surface-emitting device 20 lack the reinforcement of the light rays from adjacent backlight blocks, resulting in the lowest brightness. Therefore, the processing circuit 302 calculates an adjusted driving current corresponding to each backlight block. The driving circuit 306 generates an adjusted driving current corresponding to each backlight block to drive the backlight block of the surface-emitting device 20. As shown in FIG. 8 , the number next to each backlight block indicates the adjusted driving current corresponding to the backlight block, measured in milliamperes. In short, the embodiment of the present invention uses the corresponding adjustment coefficients and adjustment values to generate the adjusted driving current, and performs numerical compensation on the driving current, especially for the backlight blocks closer to the peripheral edges of the surface-emitting device 20 and for the backlight blocks at the four corners of the surface-emitting device 20, thereby improving the display uniformity, achieving brightness compensation in dark areas and the appearance compensation of the entire light-emitting surface, effectively optimizing the brightness distribution expression of the surface-emitting device 20, solving the problem of brightness unevenness, making the adjusted driving current curve smoother, and effectively reducing the overall power consumption.

[0036] 8, the backlight blocks of the surface-emitting device 20 are driven by the adjusted driving currents mainly generated by the processing circuit 302 and the driving circuit 306. The closer the backlight block is to the peripheral edge of the surface-emitting device 20, the larger the corresponding adjusted driving current. The closer the backlight block is to the interior of the surface-emitting device 20, the smaller the corresponding adjusted driving current. In this way, the adjusted driving currents generated by the backlight control circuit 30 effectively optimize the luminance distribution of the surface-emitting device 20 and significantly improve the problem of uneven luminance. For example, the surface-emitting device 20 may be divided into multiple backlight regions. Each backlight region includes at least one backlight block. The peripheral backlight region is closer to the edge of the surface-emitting device 20 than the inner backlight region, or the inner backlight region is closer to the center of the surface-emitting device 20 than the peripheral backlight region. The drive circuit 306 generates an adjusted drive current for the peripheral backlight region (e.g., 32.049 mA at the boundary between BC5 and BR3), which is larger than the adjusted drive current generated by the drive circuit 306 for the internal backlight region (e.g., 26.359 mA at the boundary between BC3 and BR3, or 25.44 mA at the boundary between BC4 and BR3). In this way, to address the problem of dark peripheral edges and low contrast that always occurs in display devices employing conventional backlight control circuits that dim with a constant current, the backlight blocks closer to the peripheral edges of the surface-emitting device 20 have larger adjusted drive currents, and the backlight blocks closer to the interior of the surface-emitting device 20 have smaller adjusted drive currents, the luminance distribution at the edges of the surface-emitting device 20 can be effectively optimized, and the problem of uneven luminance can be significantly improved. In addition, the current for driving the backlight block of the surface emitting device 20 is called a driving current, and in the embodiments of the present invention, it is referred to by different names such as driving current, preliminary driving current, original driving current, and adjusted driving current. These names are used to distinguish between different situations, and the scope of the present invention should not be limited so that the so-called driving current can only be interpreted as any one of the above.

[0037] In some embodiments, as shown in FIG. 9 , the surface emitting device 20 is divided into backlight areas 902, 904, and 906. Of these three backlight areas 902, 904, and 906, the backlight area 902 may be an internal backlight area (which may be referred to as a first backlight area), and the backlight areas 904 and 906 may be peripheral backlight areas (which may both be referred to as a second backlight area). The backlight area 904 surrounds the backlight area 902, and the backlight area 906 surrounds the backlight area 904. Similarly, of the two backlight areas 904 and 906, the backlight area 904 may be an internal backlight area (which may be referred to as a second backlight area), and the backlight area 906 may be a peripheral backlight area (which may be referred to as a third backlight area). Therefore, the backlight area 904 may be identified as an internal backlight area or a peripheral backlight area depending on its location. More specifically, the backlight region 902 includes a backlight block B33. The backlight region 904 includes backlight blocks B22 to B24, B32, B34, and B42 to B44. The backlight region 906 includes backlight blocks B11 to B15, B21, B25, B31, B35, B41, B45, and B51 to B55. The drive circuit 306 generates an adjusted drive current I1 to drive the light sources of the backlight blocks in the backlight region 902. The drive circuit 306 generates an adjusted drive current I2 to drive the light sources of the backlight blocks in the backlight region 904. The drive circuit 306 generates an adjusted drive current I3 to drive the light sources of the backlight blocks in the backlight region 906. The adjusted drive current I2 is greater than the adjusted drive current I1. The adjusted drive current I3 is greater than the adjusted drive currents I1 and I2. For example, but not limited to, the adjusted drive current I1 is 1 mA, the adjusted drive current I2 is 2 mA, and the adjusted drive current I3 is 3 mA. The backlight area located inside may include a central backlight block of the surface emitting device 20. The backlight area 902 includes, for example, a backlight block B33 (central backlight block).The peripheral backlight area may include at least one peripheral edge backlight block. For example, the backlight area 906 includes the peripheral edge backlight block. As shown in FIG. 9 , the backlight area 906 includes the backlight blocks in the first and last columns and the backlight blocks in the first and last rows of the surface emitting device 20.

[0038] In some embodiments, the light sources of the backlight blocks of the surface emitting device 20 are driven by the adjusted driving currents calculated and generated by the processing circuit 302 and the driving circuit 306. The closer the backlight block is to the peripheral edge of the surface emitting device 20, the larger the corresponding adjusted driving current. The closer the backlight block is to the interior of the surface emitting device 20, the smaller the corresponding adjusted driving current. At least one corner backlight block has the largest adjusted driving current. The corner backlight blocks are disposed at the corners (which may be referred to as third backlight areas) of the surface emitting device 20. For example, as shown in FIG. 10 , the surface emitting device 20 is rectangular, and the corner backlight blocks are disposed at the four corners of the surface emitting device 20. More specifically, the surface emitting device 20 is divided into backlight areas 1002, 1004, and 1006. The backlight area 1002 may be an internal backlight area, and the backlight area 1004 may be a peripheral backlight area. The backlight area 1004 surrounds the backlight area 1002. The backlight region 1002 includes backlight blocks B22 to B24, B32 to B34, and B42 to B44. The backlight region 1004 includes backlight blocks B12 to B14, B21, B25, B31, B35, B41, B45, and B52 to B54. The backlight region 1006 includes backlight blocks B11, B15, B51, and B55. The drive circuit 306 generates an adjusted drive current I1 to drive the light sources of the backlight blocks in the backlight region 1002. The drive circuit 306 generates an adjusted drive current I2 to drive the light sources of the backlight blocks in the backlight region 1004. The drive circuit 306 generates an adjusted drive current I3 to drive the light sources of the backlight blocks in the backlight region 1006. The adjusted drive current I2 is greater than the adjusted drive current I1. The adjusted driving current I3 is greater than the adjusted driving currents I1 and I2. As shown in Fig. 10, the adjusted driving current for driving the corner backlight blocks of the surface light emitting device 20 is greater than the adjusted driving current for driving the other backlight blocks.For example, the adjusted driving current I1 is 1 mA, the adjusted driving current I2 is 2 mA, and the adjusted driving current I3 is 3 mA, but is not limited thereto. The corner backlight blocks can use multiple light sources 208 connected in parallel, resulting in a high total current for the corner backlight blocks, while the other backlight blocks (not in the corners) can use a single light source 208, resulting in a low total current for the corner backlight blocks. This allows for greater current compensation for the four corners of the surface emitting device 20, where the brightness is most insufficient, thereby effectively alleviating the problem of brightness unevenness. In short, the embodiment of the present invention generates adjusted driving currents using corresponding adjustment coefficients and adjustment values to drive the light emitting device 20, thereby effectively optimizing the brightness distribution of the surface emitting device 20 and significantly alleviating the problem of brightness unevenness.

[0039] In some embodiments, as shown in FIG. 11 , the surface emitting device 20 is divided into backlight areas 1102, 1104, and 1106. Among the backlight areas 1102, 1104, and 1106, the backlight area 1102 may be an internal backlight area (which may be referred to as a first backlight area), and the backlight areas 1104 and 1106 may be peripheral backlight areas (which may be referred to as a second backlight area and a third backlight area, respectively). The backlight area 1104 surrounds the backlight area 1102, and the backlight area 1106 at least partially surrounds the backlight area 1104. The backlight areas 1102 and 1104 are both rectangular. The adjusted drive current for driving the backlight blocks in the backlight area 1106 is greater than the adjusted drive current for driving the backlight blocks in the backlight area 1104. The adjusted drive current for driving the backlight blocks in backlight area 1104 is greater than the adjusted drive current for driving the backlight blocks in backlight area 1102. For example, backlight area 1104 includes backlight blocks B1 and B2. Backlight area 1106 includes backlight blocks B3 and B4. The drive circuit 306 generates an adjusted drive current I1 to drive the light source in backlight block B1 of backlight area 1104. The drive circuit 306 generates an adjusted drive current I2 to drive the light source in backlight block B2 of backlight area 1104. The drive circuit 306 generates an adjusted drive current I3 to drive the light source in backlight block B3 of backlight area 1106. The drive circuit 306 generates an adjusted drive current I4 to drive the light source in backlight block B4 of backlight area 1106. The relationship between the adjusted driving currents I1 to I4 is I4>I3>I1>I2. That is, the adjusted driving currents (e.g., I3 and I4) for driving the backlight blocks in the backlight area 1106 are greater than the adjusted driving currents (e.g., I1 and I2) for driving the backlight blocks in the backlight area 1104.

[0040] Meanwhile, as shown in FIG. 11 , the surface emitting device 20 further includes an outer frame 1100. The outer frame 1100 is surrounded by the outside of the backlight blocks of the surface emitting device 20. Among the light emitting blocks located below the backlight blocks on the same edge, the driving current for driving the light emitting diodes farther from the outer frame 1100 is larger than the driving current for driving the light emitting diodes closer to the outer frame 1100. For example, as shown in FIG. 11 , backlight blocks B1 and B2 in the backlight region 1104 are located on the same edge, and the distance between the light emitting diode LS1 of the backlight block B1 and the outer frame 1100 is larger than the distance between the light emitting diode LS2 of the backlight block B2 and the outer frame 1100. That is, the light emitting diode LS1 of the backlight block B1 is farther from the outer frame 1100, and the light emitting diode LS2 of the backlight block B2 is closer to the outer frame 1100. Thus, the adjusted driving current I1 for driving the light-emitting diode LS1 in the backlight block B1 is greater than the adjusted driving current I2 for driving the light-emitting diode LS2 in the backlight block B2. The backlight blocks B3 and B4 in the backlight area 1106 are located on the same edge, and the distance between the light-emitting diode LS4 in the backlight block B4 and the outer frame 1100 is greater than the distance between the light-emitting diode LS3 in the backlight block B3 and the outer frame 1100. That is, the light-emitting diode LS4 in the backlight block B4 is farther from the outer frame 1100, and the light-emitting diode LS3 in the backlight block B3 is closer to the outer frame 1100. In this case, the adjusted driving current I4 for driving the light-emitting diode LS4 in the backlight block B4 is greater than the adjusted driving current I3 for driving the light-emitting diode LS3 in the backlight block B3.

[0041] In another embodiment, reference is made to FIG. 12, which is a schematic diagram of flow 12 according to an embodiment of the present invention. Steps with the same step numbers in the flows of FIG. 3 and FIG. 12 have similar operation methods and functions, and therefore, for the sake of brevity, detailed descriptions thereof will be omitted and the description will not be repeated. As shown in FIG. 12, after step S308, step S1202 is executed. In step S1202, the processing circuit 302 may further determine whether the uniformity of each backlight block is greater than its target uniformity. If the uniformity of the backlight block is greater than the target uniformity, i.e., if the uniformity ratio is less than 1, step S310 is not executed, and the driving circuit 306 does not execute the step of generating a plurality of adjusted driving currents for the backlight block. This means that the backlight block has sufficient brightness and does not need to reduce the current value of the backlight block to reduce its brightness. For example, if the uniformity of the backlight block is greater than the target uniformity, step S1204 is performed, and the driving circuit 306 generates a driving current to drive the backlight block. Step S1204 is similar to step S302. That is, for a backlight block whose uniformity is greater than the target uniformity, the driving circuit 306 generates the original driving current to drive the backlight block without adjustment. However, if the uniformity of other backlight blocks is still less than the target uniformity, i.e., if the uniformity ratio is greater than 1, the driving circuit 306 still generates multiple adjusted driving currents for the other backlight blocks, i.e., step S310. Furthermore, because the adjustment coefficient is an exponential, the change in response to the adjustment value is exponential rather than a simple linear increase. Therefore, if the uniformity ratio of the backlight block is greater than 1, the adjustment value is more strongly increased to improve the current value of the backlight block and compensate for areas with insufficient brightness.

[0042] Flow 3 shown in Figure 3 is designed on the premise that the light source module 202 emits light uniformly. If the light source module 202 itself has a defect that causes it to emit light unevenly, the light source module 202 must first be corrected to emit light uniformly. See Figure 15 for how to generate a light source module 202 with uniform light emission characteristics after correction. Figure 15 is a schematic diagram of Flow 15 according to an embodiment of the present invention. Flow 15 includes the following steps:

[0043] Step S1500: Start.

[0044] Step S1502: Generate a plurality of pre-driving currents to drive the surface light emitting device so that a plurality of light-emitting blocks generate a plurality of luminance values.

[0045] Step S1504: Measure a plurality of luminance values of a plurality of light emission blocks.

[0046] Step S1506: Calculate the average value of a plurality of luminance values from a plurality of light-emitting blocks of the light source module, and calculate the standard deviation of the plurality of luminance values from the average value of the plurality of luminance values.

[0047] Step S1508: If the standard deviation is greater than or equal to the threshold, generate multiple compensation values, and generate multiple compensation driving currents based on the generated compensation values to drive multiple light-emitting blocks; if the standard deviation is less than the threshold, stop generating the multiple compensation values, and use the multiple compensation driving currents as multiple driving currents to drive the surface emitting device.

[0048] Step S1510: End.

[0049] According to Flow 15, in step S1502, the driving circuit 306 generates a plurality of pre-driving currents to drive the surface light-emitting device 10 so that the plurality of backlight blocks of the surface light-emitting device 10 generate a plurality of luminance values. In step S1504, the measurement circuit 304 measures a plurality of luminance values of the plurality of backlight blocks of the surface light-emitting device 10. In step S1506, the processing circuit 302 calculates an average value of the plurality of luminance values generated by the plurality of light-emitting blocks of the light source module 202 and calculates a standard deviation of the plurality of luminance values from the average value of the plurality of luminance values. In step S1508, if the standard deviation is greater than or equal to a threshold, the processing circuit 302 generates a plurality of compensation values and combines the plurality of pre-driving currents with the plurality of compensation values to convert them into a plurality of compensation driving currents. The driving circuit 306 generates the plurality of compensation driving currents to drive the plurality of light-emitting blocks of the surface light-emitting device 10. This confirms whether the bright and dark areas are within the standard range, thereby solving the problem of the bright area being too bright and the dark area being too dark. If the standard deviation is smaller than the threshold, the processing circuit 302 stops generating the compensation values and sets the compensation driving currents as the driving currents generated in step S302 of flow 3. Flow 15 can be applied before the execution of flow 3 to obtain the driving currents, thus achieving the brightness uniformity requirement more quickly and effectively.

[0050] Those skilled in the art may combine, modify, or change the above embodiments within the spirit of the present invention, but are not limited to this. All of the above descriptions, steps, and / or flows (including suggested steps) can be realized in the form of hardware, software, firmware (i.e., a combination of hardware devices and computer instructions, where data in a hardware device is read-only software data), electronic systems, or combinations of the above devices. Hardware may include analog, digital, and hybrid circuits (i.e., microcircuits, microchips, or silicon chips). Electronic systems may include systems on chips (SoCs), systems in packages (SiPs), computer modules (CoMs), and display devices. The procedures and embodiments of the present invention may exist in the form of program code or instructions and be stored in a storage device. The storage device may be a computer-readable storage medium, which may include, but is not limited to, a read-only memory (ROM), a flash memory, a random-access memory (RAM), a subscriber identity module (SIM), a hard disk, a floppy disk, or an optical disk read-only memory (CD-ROM / DVD-ROM / BD-ROM). The above flows and embodiments may be compiled into program codes or instructions and stored in the storage device. The processing circuit 302 realizes all of the above steps and functions by reading and executing the program codes or instructions stored in the storage device.The processing circuitry 302 may be, but is not limited to, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a programmable controller, a graphic processing unit (GPU), a programmable logic device (PLD), or other similar device, or a combination thereof.

[0051] In summary, display devices using conventional backlight control circuits that use constant current dimming always suffer from problems such as uneven brightness (e.g., obvious grid lines), dark surroundings, and low contrast. By contrast, driving the surface emitting device 20 with the adjusted driving current provided by the backlight control circuit according to an embodiment of the present invention improves display uniformity, compensates for the brightness of dark areas, and compensates for the appearance of the entire light-emitting surface, effectively optimizing the brightness distribution of the surface emitting device 20, significantly improving the problem of uneven brightness, effectively improving contrast, and effectively reducing power consumption.

[0052] The above is merely a preferred embodiment of the present invention, and any equivalent changes and modifications according to the claims of the present invention are within the scope of protection of the present invention. [Explanation of symbols]

[0053] 1: Display device 10: Display panel 20: Surface emitting device 202: Light source module 204: Backlight module 206: Circuit board 208: Light source 210: Diffuser 212: Optical film 3, 12, 15: Flow 30: Backlight control circuit 302: Processing circuit 304: Measurement circuit 306: Drive circuit 902, 904, 906, 1002, 1004, 1006, 1102, 1104, 1106: Backlight area 1100: Outer frame B, B1, B11~B15, B2, B21~B25, B3, B31~B35, B4, B41~B45, B51~B55: Backlight block BC1~BC5, BCm: Block row BR1~BR5, BRn: Block row C1, C2: Curve D1, D2: Direction G1~G5: Adjustment coefficient I1, I2, I3, I4: Adjusted drive current L: Light-emitting block LS1, LS2, LS3, LS4: Light-emitting diodes S300, S302, S304, S306, S308, S310, S312, S1202, S1204, S1500, S1502, S1504, S1506, S1508, S1510: Step

Claims

1. A backlight control circuit for driving a surface light emitting device, a plurality of drive currents are generated to drive the surface light emitting device, thereby causing a plurality of backlight blocks of the surface light emitting device to generate a plurality of luminance values, each backlight block including at least one light source and including a drive circuit for emitting light beams; the surface emitting device is divided into at least a first backlight area and a second backlight area, the second backlight area is closer to an edge of the surface emitting device than the first backlight area, a first driving current among the plurality of driving currents is used to drive a light source of a backlight block of the first backlight area, a second driving current among the plurality of driving currents is used to drive a light source of a backlight block of the second backlight area, the second driving current being larger than the first driving current; the surface emitting device includes a plurality of first groups and a plurality of second groups, each group including at least one backlight block, the backlight blocks arranged along a first direction are defined as the first group, and the backlight blocks arranged along a second direction are defined as the second group, and the first direction and the second direction are non-parallel; The backlight control circuit includes: a measurement circuit for measuring the plurality of luminance values of the plurality of backlight blocks; a processing circuit that calculates a plurality of uniformities of the plurality of backlight blocks based on the plurality of brightness values, sets a plurality of target uniformities, and generates a plurality of adjustment values based on the plurality of uniformities, the plurality of target uniformities, and a plurality of adjustment coefficients corresponding to the plurality of backlight blocks, and the driving circuit generates a plurality of adjusted driving currents based on the adjustment values and the plurality of driving currents to drive the plurality of backlight blocks.

2. 2. The backlight control circuit of claim 1, wherein the second backlight area includes at least one backlight block at a most peripheral edge, the surface emitting device further includes a third backlight area, the third backlight area includes at least one corner backlight block, and the second backlight area includes at least one backlight block at a most peripheral edge other than the at least one corner backlight block of the third backlight area, a third drive current among the plurality of drive currents is used to drive the backlight blocks of the third backlight area, and the third drive current is greater than the first drive current and the second drive current.

3. 2. The backlight control circuit of claim 1, wherein the surface emitting device further includes a third backlight area at least partially surrounding the second backlight area, and a third drive current among the plurality of drive currents is used to drive a backlight block of the third backlight area, and the third drive current is greater than the first drive current and the second drive current.

4. 2. The backlight control circuit according to claim 1, wherein the first backlight area and the second backlight area are both formed in a rectangular shape, the surface emitting device further includes a third backlight area at least partially surrounding the second backlight area, and a third drive current among the plurality of drive currents is used to drive a backlight block of the third backlight area, and the third drive current is greater than the first drive current and the second drive current.

5. 2. The backlight control circuit according to claim 1, wherein the surface emitting device includes a light source module, the light source module including a substrate and a plurality of light emitting diodes arranged on the substrate, the light source module being capable of defining a plurality of light emitting blocks located below the plurality of backlight blocks, at least one light emitting diode being provided within each of the light emitting blocks, the surface emitting device further having an outer frame surrounding the outside of the plurality of backlight blocks, and in the light emitting blocks below the backlight blocks on the same edge, the current for driving the light emitting diodes farther from the outer frame to emit light is greater than the current for driving the light emitting diodes closer to the outer frame to emit light.

6. 6. The backlight control circuit according to claim 5, wherein the driving circuit generates a plurality of pre-driving currents to drive the surface light-emitting device so that the plurality of light-emitting blocks generate a plurality of brightness values; a measuring circuit measures the plurality of brightness values of the plurality of light-emitting blocks; a processing circuit calculates an average value of the plurality of brightness values generated by the plurality of light-emitting blocks of the light source module and calculates a standard deviation of the plurality of brightness values based on the average value of the plurality of brightness values; if the standard deviation is equal to or greater than a threshold, the processing circuit generates a plurality of compensation values to combine the plurality of pre-driving currents and a plurality of compensation values to convert them into a plurality of compensation drive currents; the driving circuit generates the plurality of compensation drive currents to drive the plurality of light-emitting blocks; if the standard deviation is less than the threshold, the processing circuit stops generating the plurality of compensation values and drives the surface light-emitting device using the plurality of compensation drive currents as the plurality of drive currents.

7. 2. The backlight control circuit according to claim 1, wherein the processing circuit obtains a target uniformity of a central backlight block located at or near the center of the surface emitting device and on a boundary between one of the first groups and one of the second groups, and obtains target uniformities of backlight blocks located on both edges of the first group including the central backlight block among the plurality of first groups, and calculates based on a first equation to obtain a target luminance value of each backlight block in the first group, and the processing circuit obtains a target uniformity of backlight blocks located on both edges of the second group including the central backlight block among the plurality of second groups, matches the target uniformity of the central backlight block, and calculates based on a second equation to obtain a target luminance value of each backlight block in the second group, wherein the curve formed by the first equation has a first curvature, the curve formed by the second equation has a second curvature, and the first curvature is less than or equal to the second curvature.

8. a first adjustment factor of the plurality of adjustment factors corresponds to a backlight block of a first first group of the plurality of first groups, a second adjustment factor of the plurality of adjustment factors corresponds to a backlight block of a second first group of the plurality of first groups, and the first adjustment factor is different from the second adjustment factor, wherein, for each backlight block of the first first group of the plurality of first groups, the processing circuit divides a target uniformity of the backlight block of the first first group by a uniformity of the backlight block of the first first group to generate a first uniformity ratio, and uses the first adjustment factor as an index 2. The backlight control circuit of claim 1, wherein the processing circuit performs a first exponential operation on the first uniformity ratio using the second adjustment coefficient as an index to generate an adjustment value corresponding to the backlight blocks of the first first group; and for each backlight block of the second first group among the plurality of first groups, the processing circuit divides the target uniformity of the backlight block of the second first group by the uniformity of the backlight block of the second first group to generate a second uniformity ratio, and performs a second exponential operation on the second uniformity ratio using the second adjustment coefficient as an index to generate an adjustment value corresponding to the backlight blocks of the second first group.

9. 2. The backlight control circuit of claim 1, wherein a first adjustment coefficient of the plurality of adjustment coefficients corresponds to the backlight block of a first first group in the plurality of first groups, a second adjustment coefficient of the plurality of adjustment coefficients corresponds to the backlight block of a second first group in the plurality of first groups, and the first adjustment coefficient is different from the second adjustment coefficient, wherein a backlight block located at or near the center of the surface-emitting device and on the boundary between one of the first groups and one of the second groups is defined as a central backlight block, and wherein a minimum distance between the backlight block of the first first group in the plurality of first groups and the central backlight block is smaller than a minimum distance between the backlight block of the second first group in the plurality of first groups and the central backlight block, and the first adjustment coefficient corresponding to the backlight block of the first first group in the plurality of first groups is larger than the second adjustment coefficient corresponding to the backlight block of the second first group in the plurality of first groups.

10. 10. The backlight control circuit of claim 1, wherein for each backlight block, the drive circuit generates an adjusted drive current corresponding to the backlight block, wherein the adjusted drive current of the backlight block is the product of the adjustment value corresponding to the backlight block and the drive current corresponding to the backlight block.

11. 10. The backlight control circuit of claim 1, wherein for each backlight block, the processing circuit determines whether the uniformity of the backlight block is greater than a target uniformity of the backlight block; if the processing circuit determines that the uniformity of the backlight block is greater than the target uniformity of the backlight block, the driving circuit generates a driving current corresponding to the backlight block to drive the backlight block; and if the processing circuit determines that the uniformity of the backlight block is equal to or less than the target uniformity of the backlight block, the driving circuit generates an adjusted driving current corresponding to the backlight block to drive the backlight block, wherein the adjusted driving current corresponding to the backlight block is a product of an adjustment value corresponding to the backlight block and a driving current corresponding to the backlight block.

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