Backlight module and display device

Abstract

This application relates to the field of backlight module technology, specifically disclosing a backlight module and display device. This application addresses image quality issues caused by low local brightness in traditional direct-lit backlight modules, such as dark corners and dark bezels, as well as data-related optical problems such as low brightness uniformity and insufficient center brightness. By doping or coating red or blue dyes into the optical components in the corresponding problem areas, and simultaneously increasing the proportion of green phosphor in the LEDs, the application improves LED excitation efficiency and local brightness, thereby optimizing subjective issues such as dark corners, dark bezels, and brightness uniformity. Utilizing these principles, solutions can be tailored to meet specific needs, achieving improved backlight module brightness and realizing a cost-effective design.

Description

Technical Field

[0001] This application relates to the field of backlight module technology, and more particularly to backlight modules and display devices. Background Technology

[0002] Currently, the TV market mainly features two structural forms: direct-lit and edge-lit. The main technical difference lies in the LED placement method. In a direct-lit backlight module, the LED strip is placed on the bottom plane of the back panel cavity. Optical lenses diffuse the LED light energy to an emission angle of about 150°. Therefore, compared to edge-lit modules, direct-lit modules use fewer LEDs, do not require light guide plates, and better achieve local dimming, thus holding a dominant advantage.

[0003] As technology advances, the market demands increasingly higher levels of brightness, uniformity, and image quality from TV products. Traditional lenses, while opening the LED emission angle, struggle to precisely control the light pattern and brightness uniformity. This leads to subjective image quality issues such as vignetting and dark frames, as well as data-related optical problems like low brightness uniformity and insufficient center brightness. Traditional direct-lit backlight modules typically address these issues by increasing the number of LEDs, using high-value diffusers, and optical films. However, these design improvements significantly increase costs, hindering product competitiveness. Utility Model Content

[0004] This application provides a backlight module designed to optimize traditional direct-lit backlight modules in terms of issues such as dark corners, dark bezels, brightness uniformity, and center brightness without significantly increasing costs.

[0005] Another object of this application is to provide a display device based on the backlight module described in this application.

[0006] In order to solve the above-mentioned technical problems or at least partially solve the above-mentioned technical problems, as a first aspect of this application, a backlight module is provided, including a first light-emitting diode, a second light-emitting diode and an optical component, wherein the second light-emitting diode is arranged in an array, the first light-emitting diode is disposed around or at the center of the second light-emitting diode, and the optical component is disposed on the light-emitting side of the first light-emitting diode and the second light-emitting diode;

[0007] The first light-emitting diode includes a blue light chip, a support with a cavity, and a phosphor adhesive filler. The blue light chip is located in the cavity and disposed at the bottom of the cavity. The phosphor adhesive filler includes a first pigment and a second pigment. The excitation efficiency of the first pigment is higher than that of the second pigment. The phosphor adhesive filler covers the blue light chip.

[0008] The optical component has a third pigment in the corresponding area of ​​the first light-emitting diode.

[0009] Optionally, the first pigment is a green phosphor, the second pigment is a yellow phosphor, and the third pigment is a blue dye. Further optionally, the phosphor adhesive filler further includes silicone, the mass ratio of the silicone to the total mass of the phosphor is 10:1-20:1, and the mass ratio of the yellow phosphor to the green phosphor is 3:1-20:1.

[0010] Optionally, the first pigment is a green phosphor, the second pigment is a red phosphor, and the third pigment is a red dye. Further optionally, the phosphor adhesive filler further includes silicone, the mass ratio of the silicone to the total mass of the phosphor is 1:1 to 5:1, and the mass ratio of the red phosphor to the green phosphor is 1:1 to 5:1.

[0011] Optionally, the optical component includes a first lens and a second lens, the first lens being disposed on the light-emitting side of the first light-emitting diode, the second lens being disposed on the light-emitting side of the second light-emitting diode, and the first lens having the third pigment. Further optionally, the third pigment accounts for 1%-5% of the mass of the first lens.

[0012] Optionally, the optical component includes a diffuser plate, wherein the third pigment is disposed in a corresponding region of the first light-emitting diode.

[0013] Optionally, the third pigment is doped into the optical component and / or coated on the light-emitting surface of the optical component.

[0014] As a second aspect of this application, a display device is provided, including a liquid crystal panel and the backlight module described in this application.

[0015] This application addresses image quality issues such as low local brightness (e.g., dark corners, dark frames) and data-related optical problems (e.g., low brightness uniformity, insufficient center brightness) in traditional direct-lit backlight modules. It involves doping or coating the optical components in the affected areas with red or blue dyes, while simultaneously increasing the proportion of green phosphor in the LEDs. This improves LED excitation efficiency and local brightness, thereby optimizing subjective issues such as dark corners, dark frames, and brightness uniformity. Based on these principles, solutions can be tailored to specific needs to achieve enhanced backlight module brightness and realize a cost-effective design. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The image shows the LED emission curve and the LED superimposed lens emission curve in a traditional direct-lit backlight module.

[0019] Figure 2 The diagram shows the structure of the first light-emitting diode (A) and the second light-emitting diode (B, i.e., a conventional white LED);

[0020] Figure 3 The diagram shows the structure of the first light-emitting diode (A) and the second light-emitting diode (B, i.e., a conventional high color gamut white LED);

[0021] Figure 4 The image shows the optical spectrum of a conventional backlight module and a backlight module with blue dye as described in this application.

[0022] Figure 5 The diagram shows the CIE1931 color gamut coordinate system; A is the CIE1931 color gamut coordinate system diagram of a backlight module with blue dye in the optical components; B is the CIE1931 color gamut coordinate system diagram of a backlight module with blue dye in the optical components and green phosphor doped into the yellow phosphor of the LED.

[0023] Figure 6 The image shows the optical spectrum of a conventional backlight module and a backlight module with red dye as described in this application.

[0024] Figure 7 The diagram shows the CIE1931 color gamut coordinate system; A is the CIE1931 color gamut coordinate system diagram of a backlight module with red dye in the optical components; B is the CIE1931 color gamut coordinate system diagram of a backlight module with red dye in the optical components and the ratio of red phosphor to green phosphor in the LED adjusted.

[0025] Figure 8 The image shows the optical spectrum of a conventional backlight module and a backlight module with an adjusted ratio of red phosphor to green phosphor in the LED, as described in this application.

[0026] Figure 9 The diagram shows the relative positions of the first and second LEDs; A represents the first LED located at one of the four corners of the second LED; B represents the first LED located at one of the four edges of the second LED; C represents the first LED located at the center of the second LED.

[0027] Figure 10 The diagram shows the structure and relative position of the first and second lenses of this application;

[0028] Figure 11 The figure shows the L50 values ​​of LED lamp life under different mass ratios of red phosphor and green phosphor.

[0029] Figure 12 The figure shows the excitation efficiency of LED lamps with different mass ratios of red phosphor and green phosphor.

[0030] Figure 13 The diagram shown is a structural schematic of the direct-lit backlight module / display device of this application; wherein, the first pigment is a green phosphor, the second pigment is a red phosphor, and the third pigment is a red dye;

[0031] Figure 14 The diagram shown is a structural schematic of the direct-lit backlight module / display device of this application; wherein, the first pigment is green phosphor, the second pigment is yellow phosphor, and the third pigment is blue dye.

[0032] Explanation of icon numbers:

[0033] Table 1

[0034] label name label name 1 case 4 reflector 101 light outlet 401 clearance hole 102 Bending section 5 lens 2 circuit board 501 First lens 3 LED 502 Second lens 301 First LED 6 Diffuser plate 302 Second LED 7 Optical films 3011 / 3021 Blue light chip 8 LCD panel 3012 / 3022 Support with storage compartment 9 Adhesive 3013 / 3023 Fluorescent glue filler Detailed Implementation

[0035] This application discloses a backlight module and display device. Those skilled in the art can refer to the content of this document and appropriately improve the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this application. The product described in this application has been described through preferred embodiments. Those skilled in the art can obviously make modifications or appropriate changes and combinations to the product described herein without departing from the content, spirit, and scope of this application to implement and apply the technology of this application. Obviously, the described embodiments are only some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0036] It should be noted that in the description of this utility model, the terms "lateral", "longitudinal", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the road structure referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0037] In this document, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are feasible to those skilled in the art. If a combination of technical solutions contradicts each other or cannot be implemented, it should be considered that such a combination does not exist and is not within the scope of protection claimed in this application. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0039] The following provides a further description of a backlight module and display device provided in this application.

[0040] Traditional direct-lit backlight modules use LEDs whose emitted light energy is mainly concentrated within a forward angle of approximately 120°. However, by adding optical lenses to the LEDs for secondary light distribution, the light energy can be extended to approximately 150°. But traditional optical lenses struggle to precisely control the light pattern and uniformity, leading to subjective image quality issues such as vignetting and dark edges. Furthermore, traditional direct-lit backlight modules often suffer from low brightness uniformity (<55%) and low center brightness. (See...) Figure 1 Traditional direct-lit backlight modules typically increase the number of LEDs and add optical films, which significantly increases costs.

[0041] Based on the aforementioned technical problems of traditional direct-lit backlight modules, in one aspect of this application, a backlight module is provided, including a first light-emitting diode, a second light-emitting diode, and an optical component. The second light-emitting diode is arranged in an array, the first light-emitting diode is disposed around or at the center of the second light-emitting diode, and the optical component is disposed on the light-emitting side of the first light-emitting diode and the second light-emitting diode.

[0042] The first light-emitting diode includes a blue light chip, a support with a cavity, and a phosphor adhesive filler. The blue light chip is located in the cavity and disposed at the bottom of the cavity. The phosphor adhesive filler includes a first pigment and a second pigment. The excitation efficiency of the first pigment is higher than that of the second pigment. The phosphor adhesive filler covers the blue light chip.

[0043] The optical component has a third pigment in the corresponding area of ​​the first light-emitting diode.

[0044] See, for example Figure 2 and Figure 3 The light-emitting diode 3 of this application includes a first light-emitting diode 301 and a second light-emitting diode 302; wherein, the blue light chip 3011 in the first light-emitting diode 301 is located in the support 3012 with the storage cavity and is disposed at the bottom of the storage cavity, and the phosphor adhesive filler 3013 covers the blue light chip 3011; in some embodiments of this application, the support 3012 with the storage cavity is shaped like a bowl, and the phosphor adhesive filler 3013 covers the blue light chip 3011 and fills the entire storage cavity.

[0045] The second LED 302 is a traditional direct-lit backlight module LED, with the same structure as the first LED 301, the difference being the phosphor adhesive filler. The second LED 302 typically comes in two types depending on the phosphor adhesive filler 3023: one is a standard white LED, where the main components of the phosphor adhesive filler 3023 are silicone and yellow phosphor. When excited by blue light, the yellow phosphor generates yellow light, which then mixes with the system's blue light to become white light. The other type is a high color gamut white LED, where the main components of the phosphor adhesive filler 3023 are silicone, red phosphor, and green phosphor. The mass ratio of red phosphor to green phosphor is 5:1 to 10:1, with a higher proportion of red phosphor. When excited by blue light, the red phosphor generates red light, and the green phosphor generates green light, which then mixes with the system's blue light to become white light.

[0046] See details Figure 2When the second light-emitting diode 302 is a conventional white LED, in the first light-emitting diode 301 of this application, green phosphor is doped into the phosphor adhesive filler 3013. On the one hand, the excitation efficiency of green phosphor is much higher than that of yellow phosphor in conventional light-emitting diodes. Therefore, the doping of green phosphor into the first light-emitting diode 301 of this application can significantly increase the light intensity of the green band of the screen, thereby improving the brightness. Replacing conventional white LEDs with green phosphor can solve the defects of direct-lit backlight modules such as dark corners, dark frames, and insufficient center brightness. On the other hand, in this application, a third pigment—blue dye—can be correspondingly set in the corresponding area of ​​the optical components in the backlight module, resulting in an overabundance of blue light. The doping of a certain proportion of green phosphor into the phosphor adhesive filler 3013 of this application can correct the screen color point and ensure the standard white field color point.

[0047] See details Figure 3 When the second light-emitting diode 302 is a traditional high color gamut white LED, in the first light-emitting diode 301 of this application, the mass ratio of red phosphor to green phosphor in the phosphor adhesive filler 3013 is no higher than 5:1. Compared with the mass ratio of red phosphor to green phosphor of 5:1 to 10:1 in traditional high color gamut LEDs, this application increases the proportion of green phosphor in the first light-emitting diode 301 and reduces the proportion of red phosphor. Since green phosphor has a higher excitation efficiency than red phosphor, the heat dissipation of LED beads is reduced, which can not only improve the overall reliability of LED, but also increase the driving current, thereby improving brightness, simplifying the optical film configuration, and reducing module cost. Replacing traditional high color gamut white LEDs with it can solve the defects of direct-lit backlight modules such as dark corners, dark frames, and insufficient center brightness. On the other hand, the corresponding area of ​​the optical component in the backlight module can be provided with a third pigment - red dye, which makes the proportion of red light too high. The proportion of green phosphor in the phosphor glue filler 3013 of this application is increased to produce more green light, which can correct the screen color point and ensure the white field standard color point.

[0048] The optical components in the backlight module of this application include any components capable of controlling the transmission and processing of light, such as lenses, reflective sheets, diffusers, optical films, etc. Among them, optical films include, but are not limited to, diffuser films, brightness enhancement films, diffuser-prism composite films (DOP), microlens-prism composite films (MOP), prism-prism composite films (POP), reflective polarizing brightness enhancement composite films (COP), etc.

[0049] Since the second light-emitting diode 302 is a conventional white LED, when the area of ​​the optical component corresponding to the first light-emitting diode 301 is set with blue dye, the proportion of blue light in the light output spectrum of the backlight module can be directly increased, such as... Figure 4As shown, the blue light peak at approximately 450nm wavelength exhibits enhancement; using the CIE 1931 color coordinate system as a reference, the (x, y) color coordinates of the pure white field of the screen will drift towards the blue region (0.14, 0.08), thus deviating from the standard white field color point (0.28, 0.29), as... Figure 5 -A is shown; and because a certain proportion of green phosphor is doped in the phosphor adhesive filler 3013 of the first light-emitting diode 301 of this application to correct the color point of the screen, it can shift the (x, y) color coordinates of the display screen towards the green region (0.21, 0.71), as shown. Figure 5 As shown in -B, this achieves the standard white point color of (0.28, 0.29). It should be noted that, under normal circumstances, (0.28, 0.29) is the standard pure white point color in the CIE1931 coordinate system, which is suitable for most display products. However, different needs may have special pure white point color requirements, such as (0.27, 0.28), (0.28, 0.31), etc. This application uses the standard pure white point color of (0.28, 0.29) as an example to illustrate the technical principle.

[0050] Since the second light-emitting diode 302 is a traditional high color gamut white LED, the optical components of this application, when incorporating red dye, can directly increase the proportion of red light in the light output spectrum of the backlight module, such as... Figure 6 As shown, the red light peak at approximately 610nm wavelength exhibits enhancement; using the CIE 1931 color coordinate system as a reference, the (x, y) color coordinates of the pure white field of the screen will drift towards the red region (0.67, 0.33), thus deviating from the standard white field color point (0.28, 0.29), as... Figure 7 -A is shown; and because this application adjusts the ratio of phosphor adhesive filler 3013 in the first light-emitting diode 301, that is, reduces the proportion of red phosphor and increases the proportion of green phosphor, the (x, y) color coordinates of the display screen are shifted towards the green region (0.21, 0.71), as shown. Figure 7 As shown in -B, this achieves the standard white point color of (0.28, 0.29) for the screen.

[0051] When the backlight module of this application is working, the blue light chip 3011 emits blue light. The phosphor adhesive filler 3013, including the first pigment and the second pigment, is excited by the blue light and generates light of the corresponding color. Compared with the second light-emitting diode 302, i.e., a conventional LED, the proportion of green phosphor in the first light-emitting diode 301 is significantly increased, and the intensity of green light in the emitted light spectrum is also increased accordingly. The corresponding backlight module spectrum diagram is shown below. Figure 8As shown, a significant improvement is clearly visible at the green light peak of approximately 530nm. When the system's blue light and the corresponding generated light pass through the optical component equipped with the third pigment, the redshift or blueshift phenomena caused by the addition of the first and second pigments can be corrected, thereby mixing into a standard pure white field color point.

[0052] The excitation efficiency of green phosphors is much higher than that of red and yellow phosphors. Therefore, increasing the proportion of green phosphors in LEDs can significantly increase the light intensity of the green band of the screen, thereby improving the overall brightness. Based on this principle, the proportion of green phosphors in LEDs can be appropriately increased, and the proportion of the corresponding third pigment in the optical components can be increased simultaneously. While achieving the standard white field color point, the brightness of the corresponding area of ​​the screen can also be increased as needed.

[0053] In another aspect of this application, the first light-emitting diode 301 is disposed around the second light-emitting diode 302. In this application, "around" can refer to either the four corners or the four sides of the second light-emitting diode 302; see example. Figure 9 -A, the first light-emitting diode 301 and the second light-emitting diode 302 are both arranged in an array and disposed on the circuit board 2 on which the reflective sheet 4 is laid, wherein the first light-emitting diode 301 is located at the four corners of the second light-emitting diode 302. This array layout can solve the dark corner defect existing in traditional direct-lit backlight modules; see example. Figure 9 -B, the first light-emitting diode 301 and the second light-emitting diode 302 are both arranged in an array and disposed on the circuit board 2 on which the reflective sheet 4 is laid. The first light-emitting diode 301 is located on the four sides of the second light-emitting diode 302. This array layout can solve the dark frame defect in the traditional direct-lit backlight module.

[0054] In some embodiments of this application, the first light-emitting diode 301 is disposed at the center of the second light-emitting diode 302, see example. Figure 9 -C, the first light-emitting diode 301 and the second light-emitting diode 302 are arranged in an array and disposed on the circuit board 2 on which the reflective sheet 4 is laid, wherein the first light-emitting diode 301 is located in the center area of ​​the second light-emitting diode 302. This array layout can solve the defect of insufficient center brightness in traditional direct-lit backlight modules.

[0055] In another aspect of this application, the blue light-emitting diode 3 includes, but is not limited to, a gallium nitride blue light-emitting chip; the phosphor adhesive filler also includes silicone, and to ensure reliability, the ratio of silicone mass to total phosphor mass is 1:1-20:1, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1. 19:1, 20:1, etc.; when the first pigment is green phosphor and the second pigment is red phosphor, the mass ratio of silica gel to the total mass of green phosphor and red phosphor is 1:1-5:1; when the first pigment is green phosphor and the second pigment is yellow phosphor, the mass ratio of silica gel to the total mass of green phosphor and yellow phosphor is 10:1-20:1; in some embodiments of this application, the red phosphor includes fluoride red phosphor, such as fluoride KSF (K2SiF). 6+ Red phosphors, etc.; green phosphors include nitride green phosphors, such as nitride β-sialon green phosphors, etc.; yellow phosphors include, but are not limited to, YAG (yttrium aluminum garnet), etc. In some other embodiments of this application, the mass ratio of red phosphor to green phosphor is 1:1 ≤ mass ratio ≤ 5:1, or 1:1 ≤ mass ratio < 5:1, and more preferably 1:1-5:1, such as 1:1, 2:1, 3:1, 4:1, 4.9:1, 5:1, etc. In some other embodiments of this application, the mass ratio of yellow phosphor to green phosphor is not higher than 20:1, or is 3:1 ≤ mass ratio ≤ 20:1, such as 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, etc.

[0056] In another aspect of this application, a third pigment is uniformly doped into the optical component and / or uniformly coated on the light-emitting surface of the optical component. The more distant the optical component is from the liquid crystal panel, the better the light mixing effect and the better the effect achieved. Examples include lenses and diffusers in direct-lit backlight modules.

[0057] In some embodiments of this application, see, as an example Figure 10 The optical components include a first lens 501 and a second lens 502. The first lens 501 is located on the light-emitting side of the first light-emitting diode 301, and the second lens 502 is located on the light-emitting side of the second light-emitting diode 302. The first lens 501 has a third pigment, which is either a red dye or a blue dye. Compared with the first lens 501, the second lens 502 does not have any pigment and is mainly used on the light-emitting side of a conventional LED.

[0058] In other embodiments of this application, the optical component includes a diffuser plate 6, with a third pigment, which is a red or blue dye, disposed in the corresponding area of ​​the first light-emitting diode 301. No pigment is disposed in the diffuser plate 6 areas not corresponding to the first light-emitting diode 301.

[0059] In some embodiments of this application, the third pigment accounts for 1%-5% of the mass of the optical component, such as 1%, 2%, 3%, 4%, 5%, etc. Below 1%, a noticeable color shift effect cannot be achieved, while above 5%, the color shift will be excessive, making it impossible to correct by adjusting the phosphor ratio of the light-emitting diode. In other embodiments of this application, the red dye includes carmine red and phthalocyanine red (tetrahydroquinoline diacrylinone C). 20 H 12 One or more of N2O2 and iron oxide red; blue dyes include cobalt blue, cobalt chromium blue, ultramarine, and phthalocyanine blue (C). 32 H 16 One or more of CuN8.

[0060] In some embodiments of this application, coating the third pigment onto the light-emitting surface of the optical component can be achieved by uniformly coating the light-emitting surface with a liquid material prepared from the second pigment, while doping the third pigment into the interior of the optical component can be achieved by mixing the third pigment with the raw material of the optical component, granulating it, and then preparing it into an optical component.

[0061] In other embodiments of this application, optical components uniformly doped with a third pigment are obtained by referring to the following method:

[0062] The raw materials for preparing the optical component and the third pigment are mixed and melted uniformly. The melting temperature is between the melting point of the optical component raw materials and the melting point of the third pigment. This facilitates the uniform distribution of the third pigment in the molten optical component raw materials. Granulation is then performed first, followed by mixing with the optical component raw materials (a foaming agent can be added simultaneously if a bubble structure is required). The processes of feeding, melting, cooling and molding, thickness monitoring, and defect monitoring are repeated to obtain an optical component with the third pigment. This process of granulation before optical component preparation ensures the uniform distribution of the third pigment in the optical component, avoiding uneven distribution phenomena such as agglomeration that could lead to subjective defects and optical data deviations.

[0063] In other embodiments of this application, the application further illustrates the use of a third pigment, such as the red dye phthalocyanine red and the blue dye phthalocyanine blue, disposed within the lens:

[0064] To ensure the uniform distribution of phthalocyanine red or phthalocyanine blue, the raw materials need to be granulated first: polymethyl methacrylate (PMMA, the raw material for light guide plates) and phthalocyanine red or phthalocyanine blue raw materials are mixed evenly and then melted in the screw section at about 180℃-200℃. During this process, the PMMA material melts, while the melting points of phthalocyanine red and phthalocyanine blue are about 400℃ and 600℃ respectively, so they are not affected. The phthalocyanine red or phthalocyanine blue will be evenly distributed in the molten PMMA. Then, it is extruded, cooled, and cut into particles at the micron to millimeter level. By using the above PMMA & phthalocyanine red (phthalocyanine blue) raw materials, and then mixing them with pure PMMA particles, and repeatedly going through the processes of feeding, melting, cooling and molding, thickness monitoring, and defect monitoring, red / blue dye lenses can be obtained. The fabrication processes for other optical components such as optical films and diffusers are similar. For example, after completing the fabrication of the diffuser, a layer of red or blue dye is uniformly coated on its light-emitting surface. When fabricating optical films, red / blue dyes can be mixed with organic plastic particles. Finally, depending on the need, organic plastic can be added or not added, and the processes of feeding, melting, cooling and molding, thickness monitoring, and defect monitoring can be repeated to obtain the corresponding optical films and diffusers doped with red / blue dyes.

[0065] In comparison, the aforementioned process of incorporating a third pigment into the optical components offers better cost-effectiveness than coating processes, and the process is also relatively simple. Furthermore, given that optical components such as optical films, diffusers, and lenses are made of organic plastics such as polystyrene (PS), polymethyl methacrylate (PMMA), styrene-methyl methacrylate copolymer (MS), and polycarbonate (PC), phthalocyanine red and phthalocyanine blue are preferred third pigments due to their superior stability.

[0066] In some embodiments of this application, the light decay of LEDs under different ratios of red and green phosphors is tested by setting different mass ratios. The normal maximum current value If of a traditional high color gamut white LED is also measured. MAX It is generally set at 650mA, while the normal maximum current value of traditional ordinary color gamut white LEDs is If MAX However, the current can be set between 850mA and 1A. The reason for the difference is that the KSF red phosphor ratio is relatively high, but the excitation efficiency is low and the heat dissipation is large. If driven by a large current, it is easy to cause abnormal heat dissipation and stress cracking failure of the phosphor. The backlight module provided in this application fully optimizes the ratio of KSF red phosphor to β-sialon green phosphor. Appropriately reducing the ratio of KSF red phosphor can significantly improve the heat dissipation of LED beads, thereby increasing the current drive value. Figure 5As shown in Table 2, with a fixed forward current of 800mA, light decay tests were conducted on high color gamut LEDs with different ratios under the traditional experimental conditions of 85℃ / 85%RH. The time value when the brightness decayed to 50% was recorded and defined as the LED lifetime value, L50. The data is shown in Table 2 below. The industry standard for LED lifetime is L50 / 30000H (Typ.), which means that the brightness decays to 50% of the initial value after 30000H.

[0067] Table 2

[0068] KSF: β-sialon If / mA Test temperature / °C Test humidity / RH% 50% light decay time / H 10:1 800 85 85％ 19000 8:1 800 85 85％ 24600 5:1 800 85 85％ 31200 3:1 800 85 85％ 33500 1:1 800 85 85％ 39000

[0069] Combination Figure 11 As can be clearly seen from the results in Table 2, as the proportion of red phosphor decreases, the light decay of LEDs slows down and the reliability is improved accordingly.

[0070] In some embodiments of this application, the excitation efficiency of LEDs with different red and green phosphor mass ratios was tested, and the results are shown in [the table below]. Figure 12 ;according to Figure 12 It is clear that the excitation light intensity of the LED varies significantly under the same current when the ratio of KSF red phosphor to β-sialon green phosphor is different. As the proportion of KSF red phosphor decreases and the proportion of β-sialon green phosphor increases, the excitation light intensity of the LED increases accordingly. Furthermore, it can be observed that when the ratio of KSF red phosphor is dominant (e.g., 5:1-10:1), the LED reaches its peak excitation efficiency at 500-600mA current; further increasing the current does not significantly improve brightness, and more electrical energy is converted into heat, affecting reliability. When the ratio of KSF red phosphor to β-sialon green phosphor is roughly equal, the LED still exhibits improved excitation efficiency at 800mA.

[0071] Therefore, appropriately reducing the proportion of KSF red phosphor in high color gamut LEDs is beneficial to improving the reliability and excitation efficiency of the LED chips. When this technology is applied to backlight modules, it can highlight a very obvious brightness improvement effect, thereby reducing the number of LED chips and the configuration of films, thus achieving efficiency improvement and cost reduction.

[0072] In other embodiments of this application, the same backlight module testing platform was used to sequentially test the optical data of a traditional backlight module, a backlight module with different proportions of phthalocyanine blue pigment added to the diffuser plate, and a backlight module with different proportions of β-sialon phosphor added to the LED, as shown in Table 3 below:

[0073] Table 3

[0074]

[0075]

[0076] The brightness of backlight modules typically needs to reach above 320 nits. As can be clearly seen from the results in Table 3, the excitation efficiency of β-sialon green phosphor is much higher than that of YAG yellow phosphor. Therefore, compared with the traditional backlight module of Scheme 1, the doping of green phosphor in LEDs in Schemes 3, 5, and 7 can significantly increase the light intensity of the green band of the screen, thereby improving the overall brightness, and the standard field color point is also corrected. Under the premise that the overall mass of the phosphor adhesive and the mass ratio of silicone to phosphor remain unchanged, each additional 1% of green phosphor can increase the brightness by about 5%.

[0077] Schemes 2, 4, and 6 only involve adding blue dye to the diffuser plate without adjusting the proportion of phosphor in the LED. As a result, the overall brightness decreases and the standard difference color point deviates.

[0078] In another aspect of this application, the backlight module is a direct-lit backlight module, and the optical components include a lens disposed on the light-emitting side of the light-emitting diode. Furthermore, the optical components also include one or more of a diffusion film, a diffusion plate, and a reflective sheet.

[0079] See, for example Figure 13 and Figure 14 The direct-lit backlight module includes:

[0080] The housing 1 is surrounded by a cavity, and the cavity has a light outlet 101.

[0081] Circuit board 2 is disposed on the bottom of the accommodating cavity;

[0082] The reflector 4 is disposed on the side of the circuit board 2 away from the bottom of the accommodating cavity and extends along the side wall of the accommodating cavity to the side wall of the light outlet 101; the reflector 4 on the circuit board 2 has a clearance hole 401.

[0083] Light-emitting diode 3 is disposed in clearance hole 401 and mounted on circuit board 2. Light-emitting diode 3 includes a first light-emitting diode 301 and a second light-emitting diode 302. The first light-emitting diode 301 includes a blue LED chip 3011, a support 3012 with a storage cavity, and a phosphor adhesive filler 3013. The blue LED chip 3011 is located inside the storage cavity and at the bottom of the cavity. The phosphor adhesive filler 3013 covers the blue LED chip 3011. The second light-emitting diode has the same structure except for the phosphor adhesive filler. See the structural diagram. Figure 2 and Figure 3The fluorescent powder adhesive filler 3013 includes red fluorescent powder and green fluorescent powder, with a mass ratio of red fluorescent powder to green fluorescent powder not exceeding 5:1; or the fluorescent powder adhesive filler 3013 includes yellow fluorescent powder and green fluorescent powder; while the fluorescent powder adhesive filler 3023 includes red fluorescent powder and green fluorescent powder, with a mass ratio of red fluorescent powder to green fluorescent powder of 5:1 to 10:1; or the fluorescent powder adhesive filler 3023 includes only yellow fluorescent powder.

[0084] Lens 5 includes a first lens 501 and a second lens 502. The first lens 501 is doped with red / blue dye and is disposed around the first light-emitting diode 301; the second lens 502, which is not doped with dye, is disposed around the second light-emitting diode 302.

[0085] A diffuser plate 6 is placed over the light outlet 101 of the accommodating cavity, and a light-emitting diode 3 is positioned perpendicular to the diffuser plate 6.

[0086] Optical film 7 is disposed on the side of diffuser plate 6 away from housing 1 and abuts against it.

[0087] In some embodiments of this application, the edge of the housing 1 is bent toward the diffuser plate 6 to form a bend 102.

[0088] In the above-mentioned direct-lit backlight module, the housing 1 is arranged to form a cavity, and a light outlet 101 communicating with the cavity is opened on the housing 1 at the position corresponding to the cavity. The backlight composed of the light-emitting diode 3 and the lens 5 is set at the bottom of the cavity, specifically on the circuit board 2 in the clearance hole 401. The light-emitting diode 3 is set perpendicular to the diffuser plate 6 in order to achieve the best light emission effect.

[0089] During operation, circuit board 2 provides power to LED 3, which emits blue light. The phosphor adhesive filler 3013 in the first LED 301 increases the proportion of green phosphor and reduces the proportions of red and yellow phosphor. The resulting light includes system blue light, green light excited by blue light, and red or yellow light. Lens 5 then expands the collimated LED light energy to a divergence angle of approximately 150°. The first lens 501 is doped with a third pigment for correction. The various colors of light are mixed to achieve a standard white field color point, significantly improving screen brightness. Further brightness gain and diffusion effects from reflector 4, diffuser 6, and optical film 7 provide a uniform surface light source for the LCD panel 8. Utilizing this principle, without changing the number of LEDs or the backlight module architecture, increasing the LED driving current significantly improves the backlight module brightness without incurring additional costs, facilitating a cost-effective module solution. This is highly advantageous for designs requiring high brightness and high energy efficiency in backlight modules.

[0090] In another aspect of this application, a display device is provided, including a liquid crystal panel 8 and any of the backlight modules provided in this application.

[0091] In other embodiments of this application, the display device includes a display panel 8 and the aforementioned direct-lit backlight module, as shown in the schematic diagram. Figure 13 and Figure 14 Based on the aforementioned direct-lit backlight module, the LCD panel 8 is disposed over the light outlet 101 and abuts against the bent portion 102. The abutment method includes, but is not limited to, using an adhesive 9 (such as a rubber strip) for connection.

[0092] Based on the technical principles of the present application, it is understood that the present application sets a third pigment in the corresponding area of ​​the optical components of the backlight module, causing a red shift or blue shift, which can improve the color gamut of the display device. At the same time, in order to correct the (x, y) color coordinates to the standard pure white field color point (e.g., x = 0.28, y = 0.29), the phosphor ratio of the LED beads is adjusted, that is, the proportion of the original red or yellow phosphor is reduced and the proportion of green phosphor is increased, which will shift the (x, y) color coordinates of the display device towards the green area. Meanwhile, under the same blue light chip excitation, green phosphor has a higher excitation efficiency than red and yellow phosphor. As the proportion of green phosphor in the LED increases, the brightness level of the LED can be increased simultaneously. Thus, the optical components and light-emitting diodes can be set according to the number and position of the dark corners, dark frames and areas that need to be optimized and whose brightness needs to be increased on the display device. This can be a partial setting or a complete setting, so as to make up for the defects of the traditional direct-lit backlight module at a lower cost without increasing the number of LEDs, high-value diffuser plates and optical gain films. Moreover, the reduced heat dissipation of LED beads not only improves the overall reliability of LEDs, but also increases the driving current, thereby improving brightness, simplifying optical film configuration, and reducing module costs.

[0093] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0094] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A backlight module, characterized in that, It includes a first light-emitting diode, a second light-emitting diode, and an optical component. The second light-emitting diode is arranged in an array, and the first light-emitting diode is disposed around or in the center of the second light-emitting diode. The optical component is disposed on the light-emitting side of the first light-emitting diode and the second light-emitting diode. The first light-emitting diode includes a blue light chip, a support with a cavity, and a phosphor adhesive filler. The blue light chip is located in the cavity and disposed at the bottom of the cavity. The phosphor adhesive filler includes a first pigment and a second pigment. The excitation efficiency of the first pigment is higher than that of the second pigment. The phosphor adhesive filler covers the blue light chip. The optical component has a third pigment in the corresponding area of ​​the first light-emitting diode.

2. The backlight module of claim 1, wherein, The first pigment is a green phosphor, the second pigment is a yellow phosphor, and the third pigment is a blue dye.

3. The backlight module of claim 1, wherein, The first pigment is a green phosphor, the second pigment is a red phosphor, and the third pigment is a red dye.

4. The backlight module of claim 1, wherein, The optical component includes a first lens and a second lens. The first lens is disposed on the light-emitting side of the first light-emitting diode, and the second lens is disposed on the light-emitting side of the second light-emitting diode. The first lens is provided with the third pigment.

5. The backlight module of claim 1, wherein, The optical component includes a diffuser plate, wherein the third pigment is disposed on the diffuser plate in a corresponding area of ​​the first light-emitting diode.

6. The backlight module according to any one of claims 1-5, wherein, The third pigment is doped into the optical component and / or coated on the light-emitting surface of the optical component.

7. A display device, characterized by comprising: It includes a liquid crystal panel and a backlight module as described in any one of claims 1-6.

Images