Backlight module and display device IV

Abstract

A display device (100) includes a display panel (110), a first light source (E), and a second light source (F). The first and second light sources (E, F) are aligned with the first light spot (5) and the second light spot (6), respectively, in a direction perpendicular to the substrate (310). The first light source (E) irradiates the first light spot (5) and the third light spot (M) with a brightness of a first value, and irradiates the second light spot (6) with a brightness of a second value. The first light source (E) irradiates an intermediate spot (N) between the first spot and the second spot with a brightness value half the sum of the first value and the second value.

Description

Technical Field

[0001] The present invention relates to backlight modules and display devices including backlight modules, and more particularly, to backlight modules that use lenses to improve brightness uniformity. Background Technology

[0002] Liquid crystal display (LCD) devices are widely used in industry and daily life. An LCD device consists of an LCD panel and a backlight module. The LCD panel receives light from the backlight module and displays images by adjusting the transmittance of pixels made of liquid crystal elements. Backlight modules are available in direct-type and edge-type. In a direct-type backlight module, the light source is positioned facing the rear surface of the LCD panel, directly illuminating the LCD panel. In an edge-type backlight module, the light source is positioned on one side of the LCD panel, and a light guide plate is positioned adjacent to the rear surface of the LCD panel to guide the light to illuminate the LCD panel. The following description describes a direct-type backlight module.

[0003] In direct-light backlight modules, an array of light-emitting diodes (LEDs) is typically used as the light source. Because the area above the LEDs receives strong illumination while the area between the LEDs receives weak illumination, uneven brightness becomes a problem, especially as LCD devices become increasingly thinner. Consequently, more LEDs are needed to improve brightness uniformity, leading to increased manufacturing costs. This invention addresses these problems. Summary of the Invention

[0004] This invention discloses a method and apparatus for a backlight module and a display device including backlight units. In one aspect, the display device includes a display panel, a substrate disposed near the display panel, and a plurality of LED light sources disposed on the substrate along a grid pattern to form a plurality of rectangular illumination units. Each illumination unit includes four LED light sources, respectively disposed at the four corners of the illumination unit, with a length L along a first direction X and a width W along a second direction Y, and corresponding rectangular areas illuminating the interface of the display device having the same length L and width W. Each LED light source includes an LED and a corresponding lens disposed above the LED, the corresponding lens guiding the light emitted from the LED to...

[0005] (1) The first corner of the corresponding rectangular area on the interface of the display device, the first corner having a first brightness value E1.

[0006] (2) The second corner of the corresponding rectangular area, the brightness of the second corner is the second brightness value E2, where the distance between the first corner and the second corner along the X direction is L.

[0007] (3) A first position (x,0) having a brightness value E(x,0), which is determined based on the change in brightness value from a first brightness value E1 at a first light spot to a second brightness value at a second light spot, wherein the first position, the first light spot, and the second light spot are located on a first boundary line between a first angle and a second angle, and x is the distance along the X direction between the first position (x,0) and the first angle.

[0008] (4) The third corner of the corresponding rectangular area, wherein the brightness of the third corner is the second brightness value, and the distance between the first corner and the third corner along the Y direction is W.

[0009] (5) A second position (0, y) having a brightness value E(0, y), which is determined based on the change in brightness value from a first brightness value E1 at the third light spot to a second brightness value at the fourth light spot, wherein the second position, the third light spot, and the fourth light spot are located on a second boundary line between the first angle and the third angle, and y is the distance along the Y direction between the second position (0, y) and the first angle.

[0010] (6) The third position (x,y) of the corresponding rectangular area has a brightness value of E(x,y), which is the product of E(x,0) and E(0,y).

[0011] On the other hand, a backlight module includes a substrate; a first light source disposed on the substrate; a second light source disposed on the substrate and close to the first light source; a first lens; and a second lens. The first light source, the first lens, and a first light spot are aligned along a direction perpendicular to the substrate, and the second light source, the second lens, and the second light spot are aligned along the same direction. Light emitted from the first light source passes through the first lens and illuminates the first and third light spots with a first value of brightness, illuminates the second light spot with a second value of brightness, and illuminates an intermediate light spot with a value that is half or substantially close to half the sum of the first and second values. The intermediate light spot is located between the first and second light spots. Attached Figure Description

[0012] The subject matter considered to be the invention is specifically pointed out and explicitly claimed in the claims. The subject matter and other features and advantages of the invention will be described in detail below with reference to the accompanying drawings. Furthermore, the graphic representation of the first appearance of the leftmost numeral is indicated by...

[0013] Figure 1 is a perspective view of an LCD device in the prior art.

[0014] Figure 2A A cross-sectional view of a display device according to an embodiment of the present invention is shown schematically.

[0015] Figure 2B and 2CThe following is a schematic illustration of an embodiment of the present invention. Figure 2A The diagram shows a cross-sectional view and a top view of the backlight module of the display device.

[0016] Figure 3A The light source of the backlight module is schematically shown in a top view according to an embodiment of the present invention.

[0017] Figure 3B and 3C The illustration schematically shows the relationship between the present invention and... Figure 3A The cross-sectional view corresponding to the backlight module shown. Figure 3D The following is a schematic illustration of an embodiment of the present invention. Figure 3A Some points on the light source interface shown.

[0018] Figure 3E and 3F Two brightness curves that represent linear changes in brightness are schematically shown.

[0019] Figure 3G The following is a schematic illustration of an embodiment of the present invention. Figure 3A Some areas on the light source interface shown.

[0020] Figure 3H It schematically shows the relationship with Figure 3B The optical path diagram corresponding to the configuration shown is shown.

[0021] Figure 3I and Figure 3J It schematically shows the relationship with Figures 3A-3D The relationship between the intensity and angle of light emitted by the light source of the relevant backlight module.

[0022] Figure 4 A schematic diagram of light passing through a concave lens is shown.

[0023] Figure 5 A schematic diagram is shown showing light shining onto a surface through a lens.

[0024] Figure 6 and Figure 7 The illustrations schematically depict light sources arranged in different configurations according to embodiments of the present invention.

[0025] Figure 8 A flowchart illustrating a lens designed for a backlight module according to an embodiment of the present invention is shown.

[0026] Figure 9 A flowchart illustrating the assembly of a backlight module and a display device according to an embodiment of the present invention is shown.

[0027] Figure 10 A structural diagram of a display device according to an embodiment of the present invention is shown. Specific Implementation

[0028] The following detailed description of the present invention, in conjunction with the accompanying drawings and embodiments, further clarifies the objectives, technical solutions, and advantages of the invention. It should be noted that the illustrative embodiments discussed in this invention are for illustrative purposes only. The invention is not limited to the disclosed embodiments.

[0029] Figure 1 shows a perspective view of a prior art display device 100. The display device 100 includes an LCD panel 110, a portion 111 comprising a filter unit and a diffuser, a spacer layer 112, and a portion 113 comprising a mini-LED array. The filter unit includes color filter elements that convert incident light into light of different wavelengths. The diffuser includes a diffuser material layer that diffuses light passing through it and improves brightness uniformity by reducing the brightness of the bright portions of the light. Layer 112 may be made of a light-transparent adhesive material (such as resin).

[0030] During operation of the display device 100, light emitted from the mini-LED array in section 113 diffuses and passes through layer 112 before illuminating section 111 or the diffuser. Because layer 112 is arranged very thinly in the thin display device 100, the lower surface of section 111 may have uneven brightness. For example, areas adjacent to mini-LEDs may appear bright, while areas between mini-LEDs may appear dark. To improve brightness uniformity, more mini-LEDs are added to the array, which increases assembly and material costs. Furthermore, even with the addition of more mini-LEDs to the mini-LED array, a diffuser is still needed to provide uniform brightness for the LCD panel.

[0031] Figure 2A A schematic cross-sectional view of a display device 200 according to an embodiment of the present invention is shown. The cross-sectional view is shown in the XZ plane. The display device 200 may include a display panel 210, a wavelength conversion unit 211, a backlight module 212, and a diffuser 213. The wavelength conversion unit 212 is adjacent to the display panel 210 and disposed between the display panel 210 and the diffuser 213. The backlight module 212 is disposed close to the display panel 210 and separated from the display module 210 by the wavelength conversion unit 211, the diffuser 213, and a region 214. The region 214 may be configured between the diffuser 214 and the backlight module 212. Optionally, the region 214 may be arranged within the backlight module 212. In some other cases, a portion of the wavelength conversion unit 211, the diffuser 213, and the region 214 may be configured inside the display panel 210. As used herein, the terms “unit,” “module,” or “component” have the same or similar meanings and may be used interchangeably.

[0032] Display panel 210 includes a pixel matrix, forming an image by controlling the transmission of light through the pixels. The light used herein can also be referred to as a ray. Since display panel 210 itself does not generate light, a backlight is required, for example, a backlight module 212. The backlight module 212 emits light to illuminate the pixels of display panel 210 to create an image. In some embodiments, display panel 210 may be an LCD panel. In this case, display panel 210 may include a liquid crystal layer, a first polarizing layer, and a second polarizing layer disposed between an upper substrate and a lower substrate. The term "layer" as used herein may also refer to an element. The liquid crystal layer is formed of liquid crystal molecules. Transparent electrodes are disposed on the upper and lower substrates. Each pixel of the LCD panel consists of a portion of liquid crystal molecules arranged between the upper and lower transparent electrodes. By applying a voltage to the pixel via the electrodes, the arrangement of the liquid crystal molecules in the pixel is changed, and a certain amount of light passes through the pixel, causing the pixel to display a specific grayscale level.

[0033] In some cases, the wavelength conversion unit 211 may comprise a color filter matrix deposited on a plate or substrate aligned with the pixels of the LCD panel. Since each pixel may have three sub-pixels corresponding to red, green, and blue respectively, three color filters are arranged for each pixel. The color filters may consist of coloring materials such as pigments or dyes, in which only light within a specific wavelength range is transmitted.

[0034] In some other cases, wavelength conversion unit 211 may comprise a matrix of wavelength conversion elements deposited on a plate or substrate. The wavelength conversion elements can absorb shorter wavelengths of light (e.g., near-ultraviolet light) and then emit longer wavelengths of light, such as red, green, or blue light. Therefore, the matrix of wavelength conversion elements can operate in a manner similar to the matrix of the color filters described above.

[0035] The diffuser 213 may include a diffuse layer made of a diffuser material and is used to provide brightness uniformity. The display panel 210, wavelength conversion unit 211, and diffuser 213 may be manufactured separately and then combined later. Optionally, the diffuser 213 and wavelength conversion unit 211 may be sequentially deposited on a plate or substrate, and the display panel 210 may subsequently be manufactured using the wavelength conversion unit 212 as a substrate. Optionally, the display panel 210 may be manufactured first, and the wavelength conversion unit 211 and diffuser 213 may be sequentially deposited on the bottom or lower surface of the display panel 210. In this case, the diffuser 214 may serve as the bottom of the display panel 210. Optionally, the display panel 210 and wavelength conversion unit 212 may be integrated together. For example, a layer containing a color filter matrix or a wavelength conversion element matrix may be configured between two layers of the display panel 210, for example, between a liquid crystal layer and a first polarizing layer (or a second polarizing layer). The wavelength conversion unit 211 may then be manufactured between the steps of depositing the liquid crystal and the first polarizing layer.

[0036] The backlight module 212 includes a plurality of light-emitting elements disposed on a substrate. The light-emitting elements form a matrix or array with a predetermined grid pattern to illuminate the display panel 210. The light-emitting elements may be referred to as light sources and include lasers, LEDs, micro-LEDs, mini-LEDs, and other small light-emitting devices. LEDs may also be referred to as LED chips. Micro-LED chips may have a size of less than 100 micrometers. Mini-LED chips may have a size of 100 to 200 micrometers or 100 to 300 micrometers. In the following description, as an example, the backlight (e.g., backlight module 212) includes mini-LEDs. Alternatively, the light source may include light-emitting elements and lenses configured for the light-emitting elements. That is, the light-emitting elements and the corresponding lenses together may be referred to as a light source.

[0037] Region 214 may include the space between the backlight module 212 and the diffuser 213, or between the mini-LED and the diffuser 213. The diffuser 213 and the space (or region 214) are configured between the wavelength conversion unit 212 (or the display panel 210) and the backlight module 212. When the wavelength conversion unit is part of the display panel 210, the wavelength conversion unit 211 may be disposed above the mini-LED and between a component of the display panel 210 and the substrate of the mini-LED. The space in region 214 may be a vacuum or filled with air or an inert gas. In some cases, the space may also be filled with a transparent adhesive material (e.g., transparent resin). Because mini-LEDs are small, they can be positioned closer to the diffuser 213 than conventional LEDs, making region 214 thinner, which can make the display device 200 thinner.

[0038] When mini-LEDs are positioned near the diffuser 213 and the display panel 210, the mini-LEDs may illuminate the diffuser 214 with uneven brightness, resulting in uneven illumination on the display panel 210. While more mini-LEDs could be added to the backlight module 212 to reduce the uneven brightness present in existing systems or devices, this would increase manufacturing costs. As described below, the present invention achieves uniform brightness without increasing the number of mini-LEDs.

[0039] Figure 2B and 2C The following is a schematic illustration of an embodiment of the present invention. Figure 2A The diagram shows a cross-sectional view 212A and a top view 212B of the backlight module 212. Cross-sectional view 212A is in the XZ plane, while top view 212B is in the XY plane. Figure 2B-2C As shown, the backlight module 212 includes mini-LEDs 221, lenses 222, and a substrate 215, on which the mini-LEDs 221 are disposed. The lenses 222 are positioned above the mini-LEDs 221 and aligned with them in the Z direction. Please note that the drawings or illustrations of components / elements (including lenses) in this invention are for illustrative purposes only and do not necessarily represent the actual shape or size of the components / elements. In some embodiments, the mini-LEDs 221 form a light source matrix or array with a predetermined grid pattern, and the lenses 222 form a lens matrix or array with the same grid pattern (e.g., as shown in the figure). Figure 2C (As shown). Figure 2B and 2C The number, size, shape, and arrangement of mini-LEDs and lenses shown in other figures of the present invention are exemplary and for illustrative purposes. Any suitable number, size, shape, and configuration may be used in the inventive backlight module and display device according to various embodiments of the present invention.

[0040] In the backlight module 212, each lens 222 is aligned with the mini-LED 221 along the Z-direction or in a direction approximately perpendicular to the substrate 215. In some cases, the lenses 222 can be manufactured individually and then bonded to the mini-LEDs 222 separately during assembly. In some other embodiments, an array of lenses 222 can be formed by molding. For example, an optical unit or optical component comprising an array of lenses 222 having a predetermined pattern can be molded. The optical unit can be disposed on the substrate 215 such that the lenses 222 are aligned with the mini-LEDs 221 respectively. Furthermore, the optical unit can be bonded to the substrate 215 after alignment has been performed.

[0041] The mini-LEDs 221 and lens 222 are configured such that when light is emitted from the mini-LEDs, the lens guides the light at different angles or changes the propagation direction of the light from each mini-LED. When the intensity of the light generated from each mini-LED is changed differently by the lens 222 at different angles, the light from the mini-LED array can be combined and illuminate the diffuser 213 with relatively uniform brightness. In one aspect, the backlight module 212 may require fewer mini-LEDs 221, thus reducing manufacturing costs. Since the backlight module 212 can produce relatively uniform brightness, the diffuser 213 can have higher transmittance compared to diffusers used in conventional display devices. Therefore, the efficiency of the display device 200 can be improved. Furthermore, when the brightness uniformity provided by the backlight module 212 exceeds a certain level, the diffuser 213 may not be necessary. That is, in some cases, the display device 200 may not include a diffuser (e.g., diffuser 213), which can further reduce manufacturing costs.

[0042] In the following description, the lens (e.g., lens 222) is designed to achieve uniform brightness based on a light source array such as a mini-LED array. In some aspects, a mini-LED can be considered a Lambert light source emitting light in a Lambert mode. Alternatively, a mini-LED can be an approximate Lambert light source. In the following description, a mini-LED is exemplarily used as a Lambert light source. Thus, when there is no lens, the light from the mini-LED is dispersed according to Lambert's emission law. When a lens is combined with a mini-LED, the light emitted by the mini-LED is dispersed according to the function of the lens. The lens used herein can refer to a lens system comprising one or more lenses. Lenses can guide light differently at different angles. Since the lens array and the mini-LED array are used to produce uniform brightness, the lens can be designed based on certain values ​​of brightness uniformity on the Lambert light source array and on a surface or interface. The term "interface" used herein refers to the boundary between two spatial regions occupied by different materials. A surface can refer to the interface between air (or a vacuum or gaseous environment) and a solid substance.

[0043] In some embodiments, when the Lambertian light source illuminates the interface via a lens and the luminance value at each point on the interface is known, the light intensity distribution in angular coordinates can be calculated. Based on the light intensity distribution in angular coordinates and the radiation pattern of the Lambertian light source, lens data can be calculated using, for example, certain methods or lens design software. Further details regarding lens design are shown below. The term "point" as used herein refers to a very small area or range surrounding a point on the interface.

[0044] Figure 3AA top view 300A of a backlight module 300 of a display device (not shown) according to an embodiment of the present invention is schematically shown. The backlight module 300 includes an array of mini-LEDs 311 with a specific pattern disposed on a substrate 310, while Figure 3A The corresponding lenses (or corresponding lens arrays with the same pattern) are omitted. The array can exemplarily comprise mini-LEDs A to I. The distance between the centers of adjacent mini-LEDs 311 along the X direction is 'a', and the distance between the centers of adjacent mini-LEDs 311 along the Y direction is 'b'. In some cases, for example, the values ​​of a and b can be in the range of 3 to 9 mm respectively. Let X2-X1 = a, X3-X2 = a, Y2-Y1 = b, and Y3-Y2 = b. In some cases, the values ​​of a and b may be different. Alternatively, in some other cases, the values ​​of a and b can be the same.

[0045] Figure 3B and 3C This illustration schematically shows the inclusion of, according to an embodiment of the invention. Figure 3A Cross-sectional views 300B and 300C show the structure of the backlight module 300. This structure may include the backlight module 300 and a diffuser 321 located above the lens 312, mini-LED 311, and backlight module 300. This structure may be part of a display device and disposed below the display panel (not shown) of the display device. The diffuser 321 has a lower surface or lower interface 322 facing the lens 312, mini-LED 311, and substrate 310. In some cases, it is assumed that the space between the diffuser 321 and the backlight module 300 is filled with air. Then, the lower interface 322 is the interface between the air and the bottom layer or base of the diffuser 321.

[0046] Figure 3D Figure 300D shows points 1 to 9 in the lower interface 322. Figure 300D shows a view taken against the Z direction (i.e., the direction facing the backlight module 300). Points 1-9 are located directly above mini-LED AI, respectively. For example, the lenses of light points 5, mini-LED E, and mini-LED E are aligned along the Z direction or approximately perpendicular to the substrate 310. Therefore, light points 1-9 form an array with the same pattern as the array formed by mini-LEDs 311. Thus, the centers of light points 1-9 are spaced a apart in the X direction and b apart in the Y direction.

[0047] like Figures 3A-3DAs shown, the mini-LED 311 emits light through the lens 312 to the diffuser 321. Without the lens, the mini-LED directly illuminates the interface, and light spots 1-9 may be brightly illuminated, while areas far from light spots 1-9 may be dimly illuminated. Therefore, the brightness of the lower interface 322 is uneven. If a regular concave lens is used to further diffuse the light from the mini-LED, light spots 1-9 may become less bright, but the interface may still have uneven brightness, with bright and dark areas. Therefore, additional mini-LEDs and diffusers are needed to make the brightness more uniform.

[0048] In this invention, the light emitted by the mini-LED 311 is processed by the lens 312. The configuration of the mini-LED array and the function of the lens 312 are set such that, during operation, when all mini-LEDs 311 are emitting light, the brightness uniformity in the area surrounded by the mini-LED AD and FI is higher than a certain value. Therefore, fewer mini-LEDs are used compared to conventional methods.

[0049] Figure 3E and 3F The diagram schematically illustrates the brightness variations along the X and Y directions when lens 312 is combined with mini-LED E. Figure 3E In the middle, the curve reflects relative to Figure 3D The brightness variation of line L1 along the X direction passing through points 4, 5, and 6. Line 1 also passes through points M′, M, N, and N′. The distances between points 4 and M′, 5 and M, 5 and N, and 6 and N′ are all e. e is less than a / 2. In some cases, e may be zero. When e equals zero, points M′, M′, N′, and N′ merge with points 4, 5, and 6, respectively. In this case, points 4 and M′, points 5, M and N, and points 6 and N′ are located at the same positions on the lower interface 322. Figure 3F In the middle, the curve reflects relative to Figure 3D The brightness variation of line L2 along the Y direction passing through points 8, 5, and 2. Line 2 also passes through points T′, T, S, and S′. The distances between points 2 and S′, 5 and S, 5 and T, and 8 and T′ are all f. The value of f is less than b / 2. In some cases, f may be zero. When f equals zero, points S′, S′, T′, and T′ merge with points 2, 5, and 8, respectively. In this case, points 2 and S′, points 5, S and T, and points 8 and T′ are located at the same positions on the lower interface 322.

[0050] like Figure 3E-3FAs shown, when the mini-LED E is powered on, the brightness along line L1 is at its maximum between light spots M and N (inclusive), and at its minimum between light spots 4 and M′, and light spots N′ and 6 (inclusive) (e.g., substantially close to zero or below a predetermined dimness). In some embodiments, the sum of the maximum and minimum values ​​along line L1 is equal to or substantially close to a predetermined value. Optionally, the brightness along line L1 is substantially close to the maximum value between light spots M and N (inclusive), and substantially close to the minimum value between light spots 4 and M′, and light spots N′ and 6 (inclusive) (e.g., substantially close to zero or below a predetermined dimness). Simultaneously, the brightness along line L2 is at its maximum between light spots T and S (inclusive), and at its minimum between light spots 8 and T′, and light spots S′ and 2 (inclusive) (e.g., substantially close to zero or below a predetermined dimness). In some embodiments, the sum of the maximum and minimum values ​​along line L2 is equal to or substantially close to a predetermined value. Optionally, the brightness along line L2 is substantially close to the maximum value between light spots T and S (including light spots T and S), and substantially close to the minimum value between light spots 8 and T' and light spots S' and 2 (including point lights 2, 8, T' and S').

[0051] The brightness along line L1 varies from a minimum to a maximum between light spots M′ and M, and between light spots N′ and N based on the formula shown below. The brightness along line L2 also varies from a maximum between light spots T′ and T, and between light spots S′ and S based on some formula. Figure 3E The curves shown follow formulas 1A to 1D.

[0052]

[0053]

[0054]

[0055]

[0056] In formulas 1A-1D and other formulas in this invention, k is a predetermined coefficient. For the purposes of the following description, k is generally negative. Formula 1A, representing the minimum value, applies when x is in the range of X1 to X1+e and X3-e to X3; formula 1B, representing the maximum value, applies when x is in the range of X2-e to X2+e; formula 1C applies when x is in the range of X1+e to X2-e; and formula 1D applies when x is in the range of X2+e to X3-e. The sum of formulas 1A and 1B equals any number 1. That is, the sum of the maximum and minimum values ​​equals a predetermined value.

[0057] Similarly, Figure 3FThe curve shown follows formula 2A-2D.

[0058]

[0059]

[0060]

[0061]

[0062] Formula 2A, representing the minimum value, applies when y is in the range of Y1 to Y1+f and Y3-f to Y3. Formula 2B, representing the maximum value, applies when y is in the range of Y2-f to Y2+f. Formula 2C applies when y is in the range of Y1+f to Y2-f, and Formula 2D applies when y is in the range of Y2+f to Y3-f. Similar to formulas 1A and 1B, the sum of formulas 2A and 2B equals any number 1.

[0063] Equations 1C-1D and 2C-2D describe linear variations where the brightness at the midpoint between two corresponding light points (e.g., between light points 4 and 5, between light points M' and M, between light points 2 and 5, or between light points S and S') is half (or substantially close to half) the sum of the maximum and minimum values. The midpoint represents a point equidistant from the two corresponding light points (e.g., light points M' and M).

[0064] Although formulas 1A, 1B, 2A, and 2B are based on the light spot 5 associated with mini-LED E, these formulas can be adjusted to suit other light spots in the lower interface 322. For illumination from mini-LED D and the range X1 to X2, the brightness along line L1 follows formula 3. Although formulas 1A-1D and 2A-2D are arranged based on the light spot 5 associated with mini-LED E, these formulas can be adjusted to suit the brightness on the lower interface 322 produced by illumination from other mini-LEDs, provided that each mini-LED AI has the same or substantially similar characteristics. For example, mini-LEDs can generate substantially similar maximum brightness values ​​on the lower interface 322. For example, for illumination from mini-LED D and the range X1 to X2, the brightness along line L1 follows formulas 3A-3C.

[0065]

[0066]

[0067]

[0068] Formula 3A, representing the minimum value, applies when x is in the range from X2-e to X2; formula 3B, representing the maximum value, applies when x is in the range from X1 to X1+e; and formula 3C, representing the maximum value, applies when x is in the range from X1+e to X2-e.

[0069] Assume that mini-LEDs D and E are both powered. When combining formulas 1A and 3B, 1B and 3A, and 1C and 3C respectively, the total brightness is always 1, which is a constant and an arbitrary number. That is, the brightness along line L1 from light spot 4 to light spot 5 (or X1 to X2) is always 1, which is a constant. Similarly, when mini-LEDs G and H are powered, the brightness on the line connecting light spots 7 and 8 is also always 1. When mini-LEDs C and F are powered, the brightness on the line connecting light spots 3 and 6 is also always 1. Constant brightness applies to other lines on the lower interface 322 that connect adjacent points 1-9 along the X or Y direction.

[0070] Figure 3G A schematic diagram 300E shows certain areas on an interface 322 according to an embodiment of the present invention. For example... Figure 3G As shown, lines L3, L5, and L7 are parallel to line L1 or the X-axis, and lines L4, L6, and L8 are parallel to line L2 or the Y-axis, respectively. Line L7 connects light points 1 and 2, and line L8 connects light points 1 and 4. Lines L3 and L5 pass through light points S and S', respectively, and lines L4 and L6 pass through light points M and M', respectively. Lines L1, L2, L7, and L8 form a rectangle (or square), with light points 1-2 and 4-5 located at the corners of the rectangle (or square). Light points 1-2 and 4-5 correspond to mini-LEDs AB and DE, which can form lighting units in some embodiments. Lines L3-L6 divide the rectangle (or square) into nine regions R1-R9.

[0071] Mini-LEDs AB and DE are energized to illuminate regions R1-R9. For each mini-LED, the brightness of any point of light is E(x)*E(y). In region R9, the brightness is controlled by the maximum and minimum values ​​of the mini-LEDs. Specifically, E(x) and E(y) for each mini-LED can be obtained based on formulas 1A-1B and 2A-2B, respectively. According to formulas 1A-1B and 2A-2B, the sum of the brightness produced by the four mini-LEDs at any point of light in region R9 is always 1. The brightness in region R8 can be obtained based on formulas 1C, 2A-2B, and 3C. According to these formulas, the sum of the brightness produced by the four mini-LEDs at any point of light in region R8 is always 1. Similarly, the brightness in region R6 can be obtained based on formulas 1A-1B and 2C-2D. According to these formulas, the sum of the brightness produced by the four mini-LEDs at any point of light in region R6 is always 1.

[0072] The brightness in region R5 is controlled by mini-LEDs AB and DE. For mini-LED E, the brightness of any point in region R5 follows Equation 4 based on Equations 1C and 2D.

[0073]

[0074] Similarly, for mini-LEDs A, B, and D, we have the following formulas to represent the brightness produced at any point in region R5. These formulas are based on formulas 1C-1D and 2C-2D.

[0075]

[0076]

[0077]

[0078] When E1(x,y), E2(x,x), E3(x,y), and E4(x,y) are added together, the total brightness is 1. Therefore, when mini-LEDs AB and DE are turned on, the brightness of any point in region R5 is 1.

[0079] Similarly, the brightness at any point in regions R1-R4 and R7 can be determined. When mini-LEDs AB and DE are turned on, the brightness at any point in regions R1-R4 and R7 is 1. Therefore, in this case, the brightness at any point in regions R1 to R9 is 1, a constant.

[0080] The above method can be used to represent the expected brightness of regions R1-R9 and other regions on the lower interface 322 of the mini-LED. For example, based on formulas 1A-1D, 2A-2D, and 4, the expected brightness of the mini-LED E on the lower interface 322 can be calculated when x ranges from X1 to X3 and y ranges from Y1 to Y3. When x or y is outside the above range, the brightness on the lower interface 3222 of the mini-LED E is set to zero.

[0081] In some embodiments, such as Figure 3A As shown, the array of mini-LEDs 311 can be considered as an array containing a predetermined grid pattern of rectangular lighting units. Each lighting unit includes four light sources arranged at its four corners. Each light source contains one mini-LED 311. Optionally, the light source may also contain one mini-LED 311 and a lens 312. Figure 3AAs shown, it may include multiple lighting units. For example, one lighting unit includes mini-LEDs A, B, D, and E at the four corners, while another lighting unit includes mini-LEDs B, C, E, and F at the four corners. The length of the lighting unit along the X direction is 'a', and the width along the Y direction is 'b'.

[0082] The lighting units illuminate the corresponding rectangular areas on the lower interface 322 using the same grid pattern (e.g., the same length a and width b). For example, as... Figure 3D As shown, the corresponding rectangular area contains light points 1, 2, 4, and 5 at its four corners. When e is equal to zero in some cases, points M' and M merge with light points 4 and 5, respectively. That is, light points M' and M are located at the corners. The line connecting the two light points at the corners of the corresponding rectangular area along the X or Y direction can be called the boundary line. The brightness in the corresponding rectangular area can be set using some adjustments using the formula described above. When the lighting unit (i.e., the four mini-LEDs) is powered on, it illuminates the corresponding rectangular area uniformly with a brightness higher than a certain value. For example, the brightness of the corresponding rectangular areas including the four boundary lines can have the same brightness value or substantially the same brightness value. Furthermore, when a mini-LED is powered on, it illuminates the corresponding rectangular area in the same way as described above. For example, when mini-LED E is powered on, it illuminates the corresponding rectangular area with a brightness higher than a certain value. Figure 3F The brightness shown illuminates the boundary line connecting points 2 and 5. The brightness can be maintained at a minimum value, change linearly from the minimum value to the maximum value, and remain at the maximum value at different segments of the boundary line.

[0083] Figure 3H The image shown is related to Figure 3B The optical path of the mini-LED E corresponding to the configuration shown is illustrated. Assume that the mini-LED E emits light rays that propagate along the optical path and illuminate point Q in the lower interface 322. The distance between the mini-LED E and the lower interface 322 is h. For example, in some cases, the value of h can be in the range of 3 to 6 mm. θ is the angle between the optical path and the interface normal (i.e., opposite to the Z direction). The distance between the mini-LED E and the light point Q is d. Let E be the luminance, and I be the luminous intensity (or luminous strength) at the light point Q. The luminance and luminous intensity follow Equation 8.

[0084] E = (I / s) 2 )*cosθ (8)

[0085] As mentioned above, since the value of brightness E in the lower interface 322 is known, the light intensity at each light spot on the interface 322 can be calculated using Formula 8.

[0086] Figure 3I and 3J The image shown is related to Figures 3A-3DThe corresponding luminous intensity emitted by the mini-LED E. Arbitrary units are used in these figures. The luminous intensity of the light spot along line L1 from X2 to X3 can be calculated using formulas 1A, 1B, 1D, and 8. For each light spot on line L1, the angle θ can also be calculated. The intensity-angle curve along line L1 from X2 to X3 is shown below. Figure 3I As shown, k has an exemplary value of -8. Similarly, the intensity versus angle curve along line L2 from Y2 to Y3 is shown below. Figure 3J As shown and calculated.

[0087] After obtaining the light intensity value through calculation, the data of the target lens can be obtained using specific software, such as lens design software. Lens data includes, for example, the shape and size of the incident and exit surfaces, the distance between the incident and exit surfaces, the lens material, and the refractive index of the lens material.

[0088] Figure 4 A schematic diagram of light passing through an exemplary concave lens 410 is shown. Lens 410 has two surfaces 412 and 413 on opposite sides. Surface 412 faces the light source 414 and can be referred to as the light incident surface. Surface 413 faces away from the light source 414 and can be referred to as the light exiting surface. Light rays strike the incident surface 412 and change their propagation direction due to refraction after passing through the incident surface 412. When exiting the lens 411 due to refraction, the light rays change their propagation direction again after passing through the exiting surface.

[0089] Designing a lens involves determining its incident and exit surfaces. In some cases, the incident surface can be determined first at the start of the lens design process to reduce computational burden. The predetermined incident surface can include, for example, a flat surface or a curved surface (e.g., a convex surface, a concave surface, an aspherical surface, or a freeform surface). The term "freeform surface" as used herein refers to a surface that has no rotational symmetry or translation around the optical axis. Since both the incident and exit surfaces are used to change the direction of light propagation, it is possible to arrange for the change in the direction of propagation of one surface to be greater than that of the other. For example, in some cases, approximately 50-70% of the change in the direction of propagation can be caused by the exit surface.

[0090] Figure 5 This is a schematic diagram illustrating the lens design process, showing how light passes through a lens and illuminates a surface. Assume a light source 511 is positioned below the lens. The lens has an incident surface 512 and an exit surface 513. The light source 511 generates light that passes through the lens and illuminates a flat surface 514 (e.g., the bottom surface of a diffuser). Assuming surface 514 receives all the light emitted from the light source 511, Equation 9 is obtained based on the law of conservation of energy.

[0091] ∫∫I(u,v)dudv=∫∫E(x,y)dxdy (9)

[0092] I(u, v) represents the light intensity emitted by light source 511 in the angular coordinate system (u, v). E(x, y) represents the brightness received on surface 514 in the Cartesian coordinate system (or orthogonal coordinate system) (x, y). Equations 10 and 11 are derived from Equation 9.

[0093] ∫∫I0 cos u*cos 2 v dudv=∫∫E(x,y)dxdy (10)

[0094] I0 cos u*cos 2 v dudv=E(x,y)dxdy (11)

[0095] I0 is a fixed value determined by pre-set conditions. Equation 11 expresses the conservation of energy in differential form, that is, the brightness received in a small region at (x, y) on surface 514 corresponds to the light intensity of a small region of light at (u, v).

[0096] When light passes sequentially through the incident surface 512 and the exit surface 513, it is refracted twice. The angle of refraction follows Snell's law of refraction. Therefore, Snell's law can be used to calculate the light path of each ray from the light source 511 through the lens to the surface 514.

[0097] When the radiation pattern of the light source 511 (e.g., light intensity at different angles) and the desired brightness value on surface 514 are known, the shapes and other data of the incident and exit surfaces 512 and 513 of the lens can be calculated. As shown above, the desired brightness value on surface 514 can be obtained by some adjustments using formulas 1A-1D, 2A-2D, and 4. The desired brightness value can also be referred to as the preset brightness value. In some cases, the incident surface 512 can be predetermined, i.e., a known surface with fixed data. The exit surface 513 is a free-form surface and can have certain predetermined initial data. For example, the exit surface 513 can have an initial shape that will be adjusted or modified multiple times during the lens design process.

[0098] Since the radiation pattern of the light source 511 and the data of the incident surface 512 are known, after the light passes through the incident surface 512, a calculation process can be performed to determine the light path or trajectory within the lens as a result of diffraction. The light can be segmented, and the trajectory of each segment within the lens can be calculated. The exit surface 513 can be divided into small regions. Each segment of the light can be incident on one or more small regions of the exit surface 513. The surface 514 can be divided into small regions. Since the trajectory of each segment of the light can be calculated after the light leaves the lens, and each trajectory passes through one or more small regions of the surface 514, the position of a corresponding small region or multiple small regions of the surface 514 can be obtained. Subsequently, when the light shines on the surface 514, the brightness in the corresponding one or more small regions can be calculated using Formula 11.

[0099] The calculated brightness value on surface 514 is compared with the expected brightness value, and the difference between them is used to adjust the data of the emitting surface 513. For example, if the brightness value in a small region of surface 514 is too large, one or more corresponding small regions of the emitting surface 513 can be identified. Subsequently, one or more corresponding small regions of the emitting surface 513 can be adjusted to redirect a portion of one or more corresponding small portions of light away from one or more corresponding small regions of surface 514, and the above steps can be repeated multiple times until the difference between the calculated brightness value and the expected brightness value on surface 514 is below a certain level. Then, the finally identified small regions of the emitting surface 513 are integrated to form the emitting surface 513.

[0100] Figure 6 and Figure 7 Light source configurations 600 and 700 according to embodiments of the present disclosure are schematically illustrated. As described above, the light source (e.g., mini-LED) can be arranged on a substrate based on lighting units. The lighting units can have a rectangular or square shape. In the following description, a rectangular shape is used exemplary. Reference Figure 6 In configuration 600, in some embodiments, the illumination unit depicted by dashed lines may include four light sources arranged at the four corners of the illumination unit. The illumination unit may have a length c along the X direction and a width d along the Y direction. Optionally, a rectangular region (not shown) may be arranged on the interface and aligned with the illumination unit along a direction perpendicular to the light source substrate. The rectangular region may have the same dimensions as the illumination unit on the interface (e.g., the same length c and width d), and the illumination unit is configured to illuminate the corresponding rectangular region with uniform brightness. In this case, the total area of ​​the rectangular region is equal to the total area of ​​the illumination unit of configuration 600.

[0101] refer to Figure 7In configuration 700, and in some other embodiments, configuration 600 (depicted in dashed lines), the lighting units may each have a light source arranged centrally. Therefore, configuration 700 has four lighting units compared to nine in configuration 600, thus significantly reducing the number of light sources required for the lighting panel (in exchange for sacrificing a small area along the panel edges). It should be noted that configurations 600 and 700 are for illustrative purposes only. In actual devices, the number of lighting units and the number of light sources (e.g., LEDs) are significantly higher.

[0102] Figure 8 A flowchart 800 illustrating a lens designed for a backlight module according to an embodiment of the present invention is shown. In step 811, data for the light source array is obtained. The array data may include the spacing of the array along the X and Y directions, which determines the distance between adjacent light sources along the X and Y directions. The light sources are arranged at grid points of the array.

[0103] In step 812, the distance between the substrate and the illumination interface is obtained. The distance and data of the light source array are the initial conditions for designing the lens. The light source is disposed on the substrate, and the illumination interface can be the bottom surface of a diffuser located at a predetermined distance from the substrate. In some cases, when the diffuser is located inside or integrated with the display panel, the illumination interface can be disposed inside the display panel. That is, the illumination interface can be configured between a layer (or component) of the substrate and the display panel.

[0104] In step 813, as part of the initial conditions, the luminance value of the illumination interface is calculated and used as the expected luminance value. The distances between adjacent light sources along the X and Y directions, as well as the distance between the substrate and the illumination interface, are used in the calculation. In some cases, formulas 1A-1D, 2A-2D, and 4 can be used to obtain the expected luminance value.

[0105] In step 814, the luminance value in the illumination interface is calculated based on the method described above. In the calculation, for example, Equation 11, Snell's law, predetermined data for the lens including incident surface data, and temporary data for the lens's exit surface can be used.

[0106] In step 815, the calculated luminance value in the illumination interface is compared with the expected luminance value. The emitting surface can be divided into small regions. Based on the comparison results, each small region of the emitting surface is adjusted separately. Subsequently, steps 814 and 815 can be repeated to calculate the luminance value in the illumination interface based on the adjustment data of the emitting surface, and the calculated luminance value is compared with the expected luminance value. When the difference between the calculated luminance value and the expected luminance value is below a certain level, the data for the emitting surface or the lens is finally determined in step 816.

[0107] Lens data can include information about the incident and exit surfaces, lens dimensions, the refractive index of the lens material, and other properties. Without a lens, a light source emits light according to its original radiation pattern. For example, a mini-LED can emit light in an approximate Lambertian pattern. When a lens is coupled to a light source, it guides the light from the source to illuminate the illumination interface. The light intensity changes from the original radiation pattern to a modified pattern. In addition to the methods described above, certain lens design software (which has been used in this field for some time) can be used to design lenses with initial conditions. In some cases, the original radiation pattern of the light source can be measured and analyzed first. In some cases, as mentioned above, the incident surface of the lens can be predetermined as an initial condition to simplify the calculation process. Alternatively, the incident and exit surfaces of the lens can be calculated, adjusted, and ultimately determined simultaneously.

[0108] Steps 811-816 describe a method for designing a lens that can be used to improve the brightness uniformity of a display device. The display device may include a mini-LED array, a lens array, and a display panel. The mini-LED array and lens array are combined to illuminate the display panel with uniform brightness. Furthermore, the mini-LED array and lens array can be scaled using the same grid pattern. For example, more mini-LEDs 311 and lenses 312 can be added. Figures 3A-3C The array shown is used to expand the array. Therefore, mini-LED arrays and lens arrays can be conveniently used in both small and large display devices. Furthermore, mini-LED arrays and lens arrays can also be used in other devices or other applications requiring uniform brightness.

[0109] Following the lens design process, lens data is recorded and transmitted to manufacturing equipment. Multiple lenses can be fabricated to construct a lens array. Optionally, lenses can be manufactured in the form of a lens array. That is, a lens array for a backlight module or display device can be prefabricated using, for example, molding methods before the assembly process.

[0110] Figure 9 A flowchart 900 illustrating the manufacture of a backlight module and a display device according to an embodiment of the present invention is shown. In step 911, a substrate for assembling the backlight module is provided. The substrate may be a semiconductor substrate comprising semiconductor materials, or an insulating substrate comprising non-conductive materials such as glass, plastic, or ceramic. Optionally, the substrate may also be a printed circuit board (PCB).

[0111] In step 912, a light source (e.g., a mini-LED) is mounted on the substrate to form a light source array having a predetermined pattern (e.g., a predetermined spacing value along the X and Y directions). In some embodiments, after performing the alignment step, the light source is bonded to the substrate with an adhesive material.

[0112] In step 913, lenses designed for the backlight module are provided. Each lens is positioned above and aligned with a light source on the substrate, and then bonded in place using an adhesive method (e.g., using an adhesive material) and lens clamps (optionally). In some embodiments, the lens array is prefabricated. The lens array can be placed on and aligned with the light source array in a direction generally perpendicular to the substrate, and then bonded using an adhesive material and lens array fixing device (optionally). In some embodiments, a housing unit can be provided for the backlight module. The housing unit can accommodate the substrate, the light source array, and the lens array. Optionally, the substrate can be placed in the housing unit before the light source is installed.

[0113] In step 914, the diffuser and wavelength conversion unit are sequentially disposed on the lens array or backlight module. The diffuser can be placed at a predetermined distance from the light source array or substrate, aligned with the lens array or light source array in a direction approximately perpendicular to the substrate, and then bonded using adhesive material. In some cases, the diffuser is fixed to the housing unit. Alternatively, the wavelength conversion unit can be placed above the diffuser, aligned with the lens array or light source array in a direction approximately perpendicular to the substrate, and then bonded using adhesive material. In some cases, the wavelength conversion unit is fixed to the housing unit.

[0114] In step 915, the display panel is placed on the wavelength conversion unit, aligned with the wavelength conversion unit in a direction approximately perpendicular to the substrate, and connected thereto. Optionally, the display panel can also be aligned with the substrate during assembly. For example, certain markings can be made on the substrate for alignment purposes. In some cases, the display panel can be fixed to a housing unit. In some embodiments, the housing unit can be designed to house and protect all components of the display device, including the backlight module and the display panel.

[0115] Steps 911-913 describe the methods and processes for manufacturing the backlight module. In some cases, the backlight module can be manufactured separately at one device and then sent to another device for assembly into a display device. Alternatively, the display device can be manufactured through a series of steps (e.g., steps 911-912) starting with mounting a light source on a substrate. These steps also include setting a lens array on the light source array, setting a diffuser on the lens array, setting a wavelength conversion unit on the diffuser, and setting a display panel on the wavelength conversion unit.

[0116] Optionally, the display panel may include a diffuser and a wavelength conversion unit. In this case, the steps of setting the diffuser and wavelength conversion unit on the backlight module as described above can be omitted. The backlight module and the display panel can be aligned and combined to directly form a display device.

[0117] In some other embodiments, the display device may not include a diffuser. Therefore, the above method can omit the step of installing the diffuser (e.g., aligning and fixing the diffuser). The wavelength conversion unit can be directly disposed on the lens array. That is, the wavelength conversion unit can be directly positioned on and aligned with the lens array during the assembly of the display device.

[0118] Figure 10 This is an exemplary structural diagram 1000 of a display device. The display device may include a display panel 1011, a wavelength conversion unit (not shown), a backlight module 1012, and a controller 1013. The display panel 1012 may be an LCD panel. The backlight module 1012 may include a mini-LED array and provide uniform brightness to the wavelength conversion unit via a lens array. The controller 1013 may include a first control circuit that sends control signals to a gate driving circuit (not shown) and a data driving circuit (not shown). The gate driving circuit and the data driving circuit are used to drive the display panel 1011 during operation of the display device 800. For example, the gate driving circuit may output a scan signal, and the data driving circuit may output a data voltage. The controller 1013 may also include a second control circuit that controls the backlight module 1012. The controller 1013 may be mounted on a PCB attached to a housing unit of the display device 1000. The display device 1000 may also include a power supply circuit (not shown) that provides and controls various voltages or currents to the display panel 1011, first and second control circuits, a gate drive circuit, a data drive circuit, and a backlight module (e.g., mini-LED).

[0119] While specific embodiments of the invention have been disclosed, those skilled in the art will understand that modifications can be made to the specific embodiments without departing from the spirit and scope of the invention. Therefore, the scope of the invention is not limited to the specific embodiments. Furthermore, it is intended that the appended claims cover any and all such applications, modifications, and embodiments within the scope of the invention.

Claims

1. A backlight module for a display device, comprising: a substrate and a plurality of LED light sources arranged on the substrate along a grid pattern to form a plurality of rectangular illumination units, characterized in that each illumination unit comprises four LED light sources respectively disposed at four corners of the illumination unit, has a length L along a first direction X and a width W along a second direction Y, and illuminates a corresponding rectangular area on an interface of the display device having the same length L and width W, wherein each LED light source comprises an LED and a corresponding lens disposed above the LED, the corresponding lens directs light rays emitted from the LED to (1) a first corner of the corresponding rectangular area on the interface of the display device, the first corner having a first luminance value E1, (2) a second corner of the corresponding rectangular area, the second corner having a second luminance value E2, wherein a distance between the first corner and the second corner along the X direction is L, (3) a first position (x, 0) having a luminance value E(x, 0) determined based on a variation of the luminance value from the first luminance value E1 at a first light point to the second luminance value at a second light point, wherein the first position, the first light point and the second light point are located on a first boundary line between the first corner and the second corner, x is a distance between the first position (x, 0) and the first corner along the X direction, (4) a third corner of the corresponding rectangular area, the third corner having the second luminance value, wherein a distance between the first corner and the third corner along the Y direction is W, (5) a second position (0, y) having a luminance value E(0, y) determined based on a variation of the luminance value from the first luminance value E1 at a third light point to the second luminance value at a fourth light point, wherein the second position, the third light point and the fourth light point are located on a second boundary line between the first corner and the third corner, y is a distance between the second position (0, y) and the first corner along the Y direction, and (6) a third position (x, y) of the corresponding rectangular area, the third position (x, y) having a luminance value E(x, y) which is a product of E(x, 0) and E(0, y).

2. The backlight module of claim 1, wherein, The corresponding lens directs the light rays to the first light point and the third light point respectively having luminance substantially close to the first luminance value E1, and the second light point and the fourth light point respectively having luminance substantially close to the second luminance value.

3. The backlight module of claim 1, wherein, The distance between the first corner and the first light point greater than zero is equal to the distance between the second corner and the second light point.

4. The backlight module of claim 1, wherein, When the four LED light sources at the four corners of the illumination unit illuminate the corresponding rectangular area, the luminance uniformity in the corresponding rectangular area on the interface of the display device exceeds a predetermined value.

5. The backlight module of claim 1, wherein, The first light point is located at the first corner of the corresponding rectangular area, and the second light point is located at the second corner of the corresponding rectangular area.

6. The backlight module of claim 1, wherein, The display device has a liquid crystal display (LCD) panel.

7. The backlight module of claim 1, wherein, The corresponding lenses of the plurality of LED light sources form a lens array having the grid pattern.

8. The backlight module of claim 7, wherein, The lens array is formed by molding.

9. The backlight module of claim 1, wherein, The length L and the width W are less than 9 millimeters respectively.

10. The backlight module of claim 1, wherein, A distance between the interface and the substrate is less than 6 millimeters.

11. A backlight module, comprising: a substrate; a first light source arranged on the substrate; a second light source arranged on the substrate and close to the first light source; a first lens; and a second lens, characterized in that the first light source, the first lens and the first light spot are aligned along a direction perpendicular to the substrate, the second light source, the second lens and the second light spot are aligned along the direction, light emitted from the first light source illuminates the first light spot and the third light spot with a first value of brightness through the first lens, illuminates the second light spot with a second value of brightness, and illuminates the intermediate light spot with a value that is half of the sum of the first value and the second value or substantially close to half of the sum of the first value and the second value, the intermediate light spot being located between the first light spot and the second light spot.

12. The backlight module of claim 11, wherein, Light emitted from the second light source illuminates the second light spot and the fourth light spot with a third value of brightness through the second lens, illuminates the third light spot with a fourth value of brightness, and illuminates the intermediate light spot with a value that is half of the sum of the third value and the fourth value or substantially close to half of the sum of the third value and the fourth value.

13. The backlight module of claim 12, wherein, The first value and the third value are substantially close to a sum and / or the second value and the fourth value are substantially close to a sum.

14. The backlight module of claim 11, wherein, The intermediate light spot is located at a midpoint between the first light spot and the second light spot.

15. The backlight module of claim 11, wherein, The third light spot is located between the first light spot and the second light spot.

16. The backlight module of claim 11, wherein, The sum of the first value and the second value is substantially close to a predetermined value.

17. The backlight module of claim 11, wherein, The first light source and the second light source comprise mini-LEDs.

18. The backlight module of claim 11, wherein, The first light source, the second light source and an additional light source form a light source array of a predetermined grid pattern, and the first lens, the second lens and an additional lens form a lens array of a predetermined grid pattern.

19. The backlight module of claim 11, wherein, The brightness changes from the third point to the intermediate point according to a predetermined function.

20. The backlight module of claim 11, wherein, The first light spot and the third light spot are located at the same position on the interface.

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