Backlight module and manufacturing method thereof
By using blue and green light-emitting diode chips combined with a red phosphor layer in the backlight module, the problems of low color purity and limited color gamut were solved, achieving a white light display effect with high color gamut and high brightness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BOE HUACAN OPTOELECTRONICS (GUANGDONG) CO LTD
- Filing Date
- 2026-03-13
- Publication Date
- 2026-06-05
AI Technical Summary
Existing backlight modules use blue light to excite yellow phosphors to convert them into white light, resulting in low color purity and limited color gamut coverage, making it difficult to meet the requirements of high-definition displays.
By using light-emitting units including blue and green light-emitting diode chips, combined with a red phosphor layer, three independent and separate narrow spectral peaks of blue, green and red light are constructed to replace yellow phosphor to form white light.
It significantly improves color purity, expands the color gamut coverage, achieves more than 100% NTSC color gamut coverage, can present richer and more realistic colors, and the brightness of the three colors is balanced to synthesize pure white light.
Smart Images
Figure CN122151405A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of display technology, and in particular to a backlight module and its manufacturing method. Background Technology
[0002] A backlight module is a device that provides a light source in a display device.
[0003] Related technology provides a backlight module including a circuit board and multiple light-emitting units. The multiple light-emitting units are arranged at intervals on the circuit board and are all electrically connected to the circuit board. Each light-emitting unit includes a blue light-emitting diode chip and phosphor covering the blue light-emitting diode chip, thereby emitting white light.
[0004] According to related technologies, the aforementioned backlight module converts yellow phosphors into white light by exciting them with blue light. However, the white light spectrum converted by this method has low energy and low color purity in the red and green light spectra, resulting in a limited color gamut coverage. This makes it difficult to meet the requirements of high-definition display and affects the display effect. Summary of the Invention
[0005] This disclosure provides a backlight module and its manufacturing method, which can improve the color gamut and enhance the display effect. The technical solution is as follows: On one hand, a backlight module is provided, the backlight module comprising: A circuit board and multiple light-emitting units, wherein the multiple light-emitting units are arranged at intervals on the circuit board and are all electrically connected to the circuit board; Each of the light-emitting units includes a plurality of light-emitting diode chips spaced apart and a fluorescent layer covering the plurality of light-emitting diode chips. The plurality of light-emitting diode chips includes at least one blue light-emitting diode chip and at least one green light-emitting diode chip, and the number of blue light-emitting diode chips is greater than or equal to the number of green light-emitting diode chips. The fluorescent layer is a red fluorescent layer.
[0006] Optionally, the light-emitting unit includes two blue light-emitting diode chips and one green light-emitting diode chip, with the green light-emitting diode chip disposed between the two blue light-emitting diode chips.
[0007] Optionally, the blue light-emitting diode chip has an emission wavelength of 457.5~462.5nm, and the green light-emitting diode chip has an emission wavelength of 520~526nm.
[0008] Optionally, the fluorescent layer is a mixture of phosphor and adhesive, wherein the phosphor is KSF red phosphor with an emission wavelength of 630~650nm.
[0009] Optionally, the spacing between two adjacent light-emitting units is 30~50mm.
[0010] Optionally, the driving current ratio of the blue light-emitting diode chip to the green light-emitting diode chip is 10:9.
[0011] Optionally, the circuit board includes a plurality of sub-circuit boards and an adapter board, the sub-circuit boards are arranged in an array, the sub-circuit boards extend along the row direction, and the adapter board extends along the column direction; The sub-circuit board includes an integrated circuit, and the integrated circuits of the plurality of sub-circuit boards are electrically connected to the adapter board respectively.
[0012] Optionally, the light-emitting unit further includes a positive electrode pin and two control pins. The positive electrode pin is electrically connected to the positive electrode of one of the blue light-emitting diode chips and the positive electrode of the green light-emitting diode chip, respectively. One of the control pins is electrically connected to the negative electrode of one of the blue light-emitting diode chips, the negative electrode of the green light-emitting diode chip, and the positive electrode of another blue light-emitting diode chip, respectively. The other control pin is electrically connected to the negative electrode of another blue light-emitting diode chip. The positive pin is electrically connected to the adapter board, and the two control pins are electrically connected to the integrated circuit.
[0013] Optionally, the adapter board includes a connector and multiple connection interfaces, the connector being electrically connected to the multiple connection interfaces and the power board respectively, and the multiple connection interfaces being electrically connected to the integrated circuits of the multiple sub-circuit boards respectively.
[0014] On the other hand, a method for manufacturing a backlight module is provided, the method comprising: Multiple light-emitting units are fabricated. Each light-emitting unit includes multiple light-emitting diode chips spaced apart and a fluorescent layer covering the multiple light-emitting diode chips. The multiple light-emitting diode chips include at least one blue light-emitting diode chip and at least one green light-emitting diode chip, and the number of blue light-emitting diode chips is greater than or equal to the number of green light-emitting diode chips. The fluorescent layer is a red fluorescent layer. The plurality of light-emitting units are mounted on a circuit board, and the plurality of light-emitting units are evenly spaced on the circuit board.
[0015] The beneficial effects of the technical solutions provided in this disclosure are: In this embodiment, multiple light-emitting units are arranged on a circuit board as a backlight module. Each light-emitting unit includes a blue light-emitting diode chip and a green light-emitting diode chip. The blue light-emitting diode chip emits blue light, and the green light-emitting diode chip emits green light. Both blue and green light pass through a red phosphor layer and finally emit white light. Compared with the related technology that uses a blue light-emitting diode chip and a yellow phosphor layer to form white light, the above structure adds a green light-emitting diode chip and replaces the yellow phosphor with a red phosphor, so that the light-emitting unit constructs three independent and separate narrow spectral peaks of blue, green, and red light. This three-primary-color narrow-band light source structure significantly improves the color purity of each primary color compared with the continuous broadband mixed light in the related technology, greatly expanding the color gamut of the backlight module. It can achieve a color gamut coverage of more than 100% of the National Television System Committee (NTSC) color broadcasting standard, and can present richer and more realistic colors, meeting the high requirements for color display in various complex scenarios. In addition, the number of blue light-emitting diode chips is greater than or equal to the number of green light-emitting diode chips. In addition to emitting blue light, blue light also excites red phosphors to produce red light. Therefore, having more or more blue light-emitting diode chips than green light-emitting diode chips can make the brightness of the three colors more balanced and synthesize pure white light. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the structure of a backlight module provided in an embodiment of this disclosure; Figure 2 This is a schematic diagram of the structure of a light-emitting unit provided in an embodiment of this disclosure; Figure 3 This is a top view of a light-emitting unit provided in an embodiment of this disclosure; Figure 4 This is a circuit diagram of a light-emitting unit provided in an embodiment of this disclosure; Figure 5 This is a circuit diagram of an integrated circuit provided in an embodiment of this disclosure; Figure 6 This is a circuit diagram of a connection interface group of an adapter board provided in an embodiment of this disclosure; Figure 7 This is a circuit diagram of a connector provided in an embodiment of this disclosure; Figure 8 This is a top view of another light-emitting unit provided in an embodiment of this disclosure; Figure 9 This is a top view of the structure of a direct-lit backlight module provided in an embodiment of this disclosure; Figure 10 This is a schematic diagram of a display panel provided in an embodiment of this disclosure; Figure 11 This is a flowchart of a backlight module manufacturing method provided in an embodiment of the present disclosure; Figure 12 This is a flowchart of another backlight module manufacturing method provided in this embodiment.
[0018] The attached figures are labeled as follows: 101: Circuit board; 102: Light-emitting unit; 103: Diffuser plate; 104: Reflective layer; 201: Support; 202: Support pin; 203: LED chip; 204: Wire; 205: Phosphor layer; 206: Lens; 1001: Sub-circuit board; 1002: Adapter board; 2031: Blue LED chip; 2032: Green LED chip; 2010: Stand-up bowl and cup; 10: Backlight module; 20: Optical film; 30: LCD panel. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.
[0020] Figure 1 This is a schematic diagram of the structure of a backlight module provided in an embodiment of this disclosure. See also... Figure 1 The backlight module includes a circuit board 101 and multiple light-emitting units 102. The multiple light-emitting units 102 are arranged at intervals on the circuit board 101 and are all electrically connected to the circuit board 101.
[0021] Figure 2 This is a schematic diagram of the structure of a light-emitting unit provided in an embodiment of this disclosure. Figure 3 This is a top view of a light-emitting unit provided in an embodiment of this disclosure. Figure 2 yes Figure 3 The cross-section at point A-A'. See also Figure 2 and Figure 3Each light-emitting unit 102 includes a plurality of light-emitting diode chips 203 spaced apart and a fluorescent layer 205 covering the plurality of light-emitting diode chips 203. The plurality of light-emitting diode chips 203 include at least one blue light-emitting diode chip 2031 and at least one green light-emitting diode chip 2032, and the number of blue light-emitting diode chips 2031 is greater than or equal to the number of green light-emitting diode chips 2032. The fluorescent layer 205 is a red fluorescent layer.
[0022] In this embodiment, multiple light-emitting units are arranged on a circuit board as a backlight module. Each light-emitting unit includes a blue light-emitting diode chip and a green light-emitting diode chip. The blue light-emitting diode chip emits blue light, and the green light-emitting diode chip emits green light. Both blue and green light pass through a red phosphor layer and finally emit white light. Compared with the related technology that uses a blue light-emitting diode chip and a yellow phosphor layer to form white light, the above structure adds a green light-emitting diode chip and replaces the yellow phosphor with a red phosphor, so that the light-emitting unit constructs three independent and separate narrow spectral peaks of blue, green, and red light. This three-primary-color narrow-band light source structure significantly improves the color purity of each primary color compared with the continuous broadband mixed light in the related technology, greatly expanding the color gamut of the backlight module. It can achieve a color gamut coverage of over 100% NTSC, presenting richer and more realistic colors, and meeting the high requirements for color display in various complex scenarios. In addition, the number of blue light-emitting diode chips is greater than or equal to the number of green light-emitting diode chips. In addition to emitting blue light, blue light also excites red phosphors to produce red light. Therefore, having more or more blue light-emitting diode chips than green light-emitting diode chips can make the brightness of the three colors more balanced and synthesize pure white light.
[0023] In this embodiment of the disclosure, the light-emitting unit 102 may include two blue light-emitting diode chips 2031 and one green light-emitting diode chip 2032, with the green light-emitting diode chip 2032 disposed between the two blue light-emitting diode chips 2031.
[0024] In this implementation, a green light chip is located between two blue light chips, forming a BGB symmetrical structure. The green light can be uniformly mixed with the blue light on both sides, eliminating the blue-green light intensity ratio drift caused by changes in viewing angle. This suppresses the white light color temperature shift, improves the color temperature consistency of white light synthesis, and is conducive to achieving a more uniform light intensity distribution and color mixing.
[0025] In other embodiments, the light-emitting unit 102 may also include other numbers of blue light-emitting diode chips 2031 and green light-emitting diode chips 2032, such as four blue light-emitting diode chips 2031 and two green light-emitting diode chips 2032.
[0026] In other embodiments, the blue LED chip 2031 and the green LED chip 2032 can also be arranged in other ways. For example, the green LED chip 2032, the blue LED chip 2031, and the blue LED chip 2032 can be arranged sequentially in a straight line. Another example is that two blue LED chips 2031 and one green LED chip 2032 can be arranged in a triangle.
[0027] In this embodiment of the disclosure, the green light-emitting diode chip 2032 and the two blue light-emitting diode chips 2031 on both sides are equally spaced.
[0028] In other embodiments, the spacing between the green light-emitting diode chip 2032 and the two blue light-emitting diode chips 2031 on both sides is not equal.
[0029] In this embodiment of the disclosure, the circuit board 101 includes a plurality of sub-circuit boards 1001, which are distributed in an array.
[0030] For example, circuit board 101 includes 36 sub-circuit boards 1001, each sub-circuit board 1001 having 16 light-emitting units 102, forming 576 partitions.
[0031] In other embodiments, the backlight module may employ a different number of sub-circuit boards 1001 and light-emitting units 102.
[0032] In this embodiment of the disclosure, a plurality of sub-circuit boards 1001 are divided into two columns, each column including 18 sub-circuit boards 1001.
[0033] In other embodiments, the plurality of sub-circuit boards 1001 are arranged in a column, each column including 36 sub-circuit boards 1001.
[0034] In this embodiment of the disclosure, multiple sub-circuit boards 1001 are electrically connected in parallel.
[0035] like Figure 1 As shown, each sub-circuit board 1001 extends along the row direction, and the adapter board 1002 extends along the column direction. Multiple sub-circuit boards 1001 are electrically connected through the adapter board 1002 arranged vertically.
[0036] The sub-circuit board 1001 includes an integrated circuit, and the integrated circuits of the multiple sub-circuit boards 1001 are electrically connected to the adapter board 1002 respectively.
[0037] In this implementation, multiple sub-circuit boards arranged along the row direction and an adapter board extending along the column direction divide multiple light-emitting unit chips into multiple zones, realizing zoned display of light-emitting diode chips.
[0038] In other embodiments, the sub-circuit board 1001 may also be electrically connected in series.
[0039] In this embodiment of the disclosure, the circuit board 101 may be a printed circuit board (PCB).
[0040] In other embodiments, circuit board 101 may also be other circuit boards, such as flexible printed circuits (FPCs).
[0041] In this embodiment of the disclosure, each sub-circuit board 1001 includes, in addition to connection lines, electronic devices such as capacitors, resistors, integrated circuits (ICs) and transient voltage suppressor diodes (TVS diodes).
[0042] Among them, capacitors and resistors are used to achieve functions such as filtering and current limiting.
[0043] The IC is used to receive external control commands, analyze signals, and output precise drive signals. Since the backlight module is controlled by the IC, each lamp can be turned on or off as needed, resulting in high contrast. Furthermore, the dark areas are less prone to cross-contamination because the lamps are turned off. Additionally, the backlight module can independently control the blue and green LED chips, resulting in high color purity and vibrant colors.
[0044] TVS diodes are used to absorb sudden voltage surges in circuits (such as instantaneous high voltages caused by power plugging / unplugging or lightning strikes).
[0045] Figure 4 This is a circuit diagram of a light-emitting unit provided in an embodiment of this disclosure. See also... Figure 4 The light-emitting unit 102 also includes a positive electrode pin and two control pins. The positive electrode pin is electrically connected to the positive electrode of a blue light-emitting diode chip 2031 and the positive electrode of a green light-emitting diode chip 2032, respectively. The control pin is electrically connected to the negative electrode of a blue light-emitting diode chip 2031, the negative electrode of a green light-emitting diode chip 2032, and the positive electrode of another blue light-emitting diode chip 2031, respectively. The other control pin is electrically connected to the negative electrode of another blue light-emitting diode chip 2031. The positive pin is electrically connected to the adapter board 1002, and the two control pins are electrically connected to the integrated circuit.
[0046] In this implementation, the positive pin is electrically connected to the adapter board and provides the operating voltage for the light-emitting unit. The two control pins are electrically connected to the integrated circuit. After the current passes through the blue light-emitting diode chip and the green light-emitting diode chip, it flows out through the control pin. The positive pin is electrically connected to the adapter board, thereby realizing independent control of the brightness of the light-emitting unit in the corresponding zone.
[0047] VLED+ represents the positive terminal of the light-emitting unit, providing the operating voltage. VLED+ is electrically connected to the positive terminals of one blue LED chip and one green LED chip, respectively. U1-CH2 and U1-CH1 are two control pins. U1-CH2 is electrically connected to the negative terminals of one blue LED chip, one green LED chip, and one blue LED chip, respectively, while U1-CH1 is electrically connected to the negative terminal of another blue LED chip.
[0048] B represents a blue LED chip, and G represents a green LED chip.
[0049] Ux-CHy represents the y-th control channel of the x-th drive unit, which is used to independently control the brightness of the light-emitting units in the corresponding partition.
[0050] by Figure 1 Taking the sub-circuit board in the upper left corner as an example, this sub-circuit board includes 16 light-emitting diode chips, numbered D1 to D16. The control channels for D1 are U1-CH1 and U1-CH2; for D2, U1-CH3 and U1-CH4; for D3, U1-CH5 and U1-CH6; for D4, U1-CH7 and U1-CH8; for D5, U2-CH1 and U2-CH2; for D6, U2-CH3 and U2-CH4; for D7, U2-CH5 and U2-CH6; and for D8, the control channels are... The control channels for D9 are U2-CH7 and U2-CH8, U3-CH1 and U3-CH2, U3-CH3 and U3-CH4 for D10, U3-CH5 and U3-CH6 for D11, U3-CH7 and U3-CH8 for D12, U4-CH1 and U4-CH2 for D13, U4-CH3 and U4-CH4 for D14, U4-CH5 and U4-CH6 for D15, and U4-CH7 and U4-CH8 for D16.
[0051] Figure 5 This is a circuit diagram of an integrated circuit provided in an embodiment of this disclosure. See also... Figure 5The integrated circuit comprises four interconnected BX7D891-8N1QFN14 chips from the chip manufacturer, Foundry Technology. The output pins (OUT) of the first chip U1 are U1-CH1 to U1-CH8; the output pins of the second chip U2 are U2-CH1 to U2-CH8; the output pins of the third chip U3 are U3-CH1 to U3-CH8; and the output pins of the fourth chip U4 are U4-CH1 to U4-CH8.
[0052] The output pins of the four chips are respectively connected to the control channels D1~D16 mentioned above, thereby controlling the on / off state of D1~D16.
[0053] The other pins in this circuit diagram (such as VCC, VDD, GND, etc.) are common chip pins and will not be described in detail here.
[0054] In this embodiment of the disclosure, the adapter board 1002 includes a connector and a plurality of connection interfaces. The connector is electrically connected to the plurality of connection interfaces and the power board, respectively. The plurality of connection interfaces are electrically connected to the integrated circuits of the plurality of sub-circuit boards 1001, respectively.
[0055] In this implementation, the connector provides positive current, and the control current flows through the electrode pins to the connection interface group, and then through multiple connection interfaces to the integrated circuits of multiple sub-circuit boards, thereby realizing the control of the light-emitting unit.
[0056] The multiple connection interfaces can be divided into multiple connection interface groups, and each connection interface group includes 3 connection interfaces.
[0057] Figure 6 This is a circuit diagram of a connection interface group for an adapter board provided in an embodiment of this disclosure. See also... Figure 6 The adapter board's connection interface group includes 36 interconnected connection interfaces (CNTs) (only 3 are shown in the figure as an example), which are electrically connected to the integrated circuits of the aforementioned 36 sub-circuit boards 1001. There are actually 12. Figure 6 The structure has pins with the same pin number from D1N1 to D1N12, which are D1N1 (IC signal).
[0058] Among them, pins D1N1~D1N12 are connected to Figure 5 VLED+ is connected to the same pin in the circuit. Figure 4 The same pins are used in this circuit diagram. Other pins (such as VCC, VDD, GND, etc.) are common pins of the chip and will not be described in detail here.
[0059] Figure 7 This is a circuit diagram of a connector provided in an embodiment of this disclosure. See also... Figure 7This connector is used on the adapter board to connect to the power board. The connector is a Changtong Technology F05039-60P-H model connector, and the connector is electrically connected to the connection interface group.
[0060] The adapter board includes two connectors, one of which, as shown in Figure CNT1, has pins D1N1 to D1N6; and the other, not shown, is CNT2, which has pins D1N7 to D1N12.
[0061] The connector is provided by VLED+. Figure 7 D1N1-D1N12 and Figure 6 The D1N1-D1N12 connectors correspond to electrical connections and function as signal input / output channels for integrated circuits, used to transmit digital signals or data. Connector control current flows through the electrode pins to the connection interface group, and then through the electrode pins of the connection interface group to the light-emitting unit, thereby controlling the light-emitting unit.
[0062] In summary, the adapter board, through CNT1 and CNT2, connects to 12 groups such as... Figure 6 The connection interface group provides signals, thereby enabling 36 connection interfaces to receive signals. The 36 connection interfaces provide signals to the integrated circuits on 36 sub-circuit boards, and the integrated circuits on each sub-circuit board provide signals to 16 light-emitting units.
[0063] See you again Figure 2 The light-emitting unit 102 also includes a bracket 201, bracket pins 202 and wires 204.
[0064] The bracket 201 includes a bracket cup 2010, wherein the bracket cup 2010 has a bowl-shaped structure. The bracket cup 210 is disposed on the circuit board 101, and the bottom of the bracket cup 210 is embedded with a bracket pin 202, which is electrically connected to the circuit board 101.
[0065] The light-emitting diode chip 203 is located on the bracket 201. The light-emitting diode chip 203 is electrically connected to the bracket pin 202 through the wire 204. The fluorescent layer 205 is located inside the bracket cup 2010 and covers the light-emitting diode chip 203.
[0066] In this implementation, multiple LED chips can be arranged together within the bracket cup. The phosphor layer, located within the bracket cup and covering the LED chips, protects them. Electrical connections are established via pins and wires to ensure good electrical conductivity.
[0067] In this embodiment of the disclosure, the material of the scaffold 201 may be a composite polymer material such as epoxy molding compound (EMC) or sheet molding compound (SMC).
[0068] For example, the material of the bracket 201 is EMC.
[0069] See you again Figure 3 The projection of the support bowl cup 2010 onto the circuit board 101 can be rectangular.
[0070] Figure 8 This is a top view of another light-emitting unit provided in an embodiment of this disclosure. See also... Figure 8 The projection of the support bowl cup 2010 onto the circuit board 101 can also be circular.
[0071] In this embodiment, the support pin 202 can be made of metal such as iron, copper, or steel, with a layer of nickel, silver, or gold plated on the surface.
[0072] For example, the support pin 202 can be made of copper metal with a layer of nickel plated on it.
[0073] In this embodiment, the emission wavelength of the blue light-emitting diode chip 2031 can be 457.5~462.5nm. Using a blue light-emitting diode chip with the above wavelength can excite phosphors with a green light-emitting diode chip to form white light, greatly expanding the color gamut of the backlight module and improving its overall color gamut.
[0074] In this embodiment of the disclosure, the blue light-emitting diode chip 2031 can be a 12V light-emitting diode chip.
[0075] In this embodiment, the green light-emitting diode chip 2032 can emit light at a wavelength of 520~526nm. Using a green light-emitting diode chip with the aforementioned wavelength can excite phosphors with a blue light-emitting diode chip to form white light, greatly expanding the color gamut of the backlight module and improving its overall color gamut.
[0076] In this embodiment of the disclosure, the green light-emitting diode chip 2032 can be a 24V light-emitting diode chip.
[0077] In this embodiment, the fluorescent layer 205 is a mixture of phosphor and adhesive, and the phosphor is KSF red phosphor with an emission wavelength of 630-650 nm. Using KSF red phosphor can ensure normal backlight brightness on the one hand, and improve the color gamut of emitted white light on the other hand.
[0078] For example, the phosphor is a KSF red phosphor with an emission wavelength of 631 nm.
[0079] In this embodiment, the height of the fluorescent layer 205 in the direction perpendicular to the circuit board 101 is 45~55μm less than the height of the support 201 in the direction perpendicular to the circuit board 101.
[0080] For example, the height of the fluorescent layer 205 in the direction perpendicular to the circuit board 101 is less than the height of the support 201 in the direction perpendicular to the circuit board 101 by 50 μm.
[0081] In other embodiments, the height of the fluorescent layer 205 in the direction perpendicular to the circuit board 101 may also be greater than or equal to the height of the support 201 in the direction perpendicular to the circuit board 101.
[0082] In this embodiment of the disclosure, the driving current ratio of the blue light-emitting diode chip 2031 and the green light-emitting diode chip 2032 is 10:9.
[0083] In this implementation, the driving current ratio of the blue LED chip to the green LED chip is 10:9, resulting in low driving current and low power consumption. This allows the backlight module to be widely used in high-end TVs, monitor modules, and other fields.
[0084] For example, the driving current of the blue light-emitting diode chip 2031 is 40mA, and the driving current of the green light-emitting diode chip 2032 is 36mA.
[0085] In this embodiment of the disclosure, the conductor 204 can be a metal conductor such as silver, gold, copper or an alloy.
[0086] For example, conductor 204 is a copper metal conductor.
[0087] In this embodiment, the conductor 204 is a T-shaped arc with a tail. The T-shaped arc can effectively improve the conductor's resistance to breakage and increase the yield of the light-emitting diode. The connection method of the tail touching the ground can increase the contact area between the conductor and the bracket pin, thereby improving the stability of the light-emitting diode.
[0088] In this embodiment of the disclosure, the height of the T-shaped arc perpendicular to the direction of the circuit board is 110~135μm.
[0089] For example, the height of the T-shaped arc perpendicular to the circuit board direction is 120 μm.
[0090] In this embodiment of the disclosure, the length of the line tail can be 50~100μm.
[0091] For example, the length of the line tail can be 80 μm.
[0092] In other embodiments, the conductor 204 can also be other types of arcs. For example, an M-shaped arc.
[0093] In this embodiment of the disclosure, the light-emitting unit 102 further includes a lens 206.
[0094] Lens 206 covers LED chip 203.
[0095] In this embodiment of the disclosure, lens 206 can be a refractive lens with a diameter of 15-19 mm.
[0096] For example, lens 206 is a refractive lens with a diameter of 17 mm.
[0097] Figure 9 This is a top view of the structure of a direct-lit backlight module provided in an embodiment of this disclosure. See also... Figure 9 The backlight module may also include a diffuser plate 103.
[0098] The diffuser plate 103 and the circuit board 101 are spaced apart and located on one side of the light-emitting surface of the multiple light-emitting units 102.
[0099] By adopting the above-mentioned direct-lit structure, since there is no light guide plate, the energy loss during the light refraction process is reduced.
[0100] In this embodiment of the disclosure, the spacing between two adjacent light-emitting units 102 is 30~50mm.
[0101] In this implementation, the light-emitting units are arranged at a small distance, and with the addition of a lens, the module thickness can be made as thin as 10~15mm.
[0102] For example, the spacing between two adjacent light-emitting units 102 is 40 mm.
[0103] In this embodiment, the diffuser plate 103 may be made of materials such as silicone, epoxy resin, or acrylic.
[0104] For example, the material of the diffuser plate 103 is silicone.
[0105] See you again Figure 9 The backlight module may also include a reflective layer 104, which is located on the side of the circuit board 101 away from the light-emitting unit 102.
[0106] Figure 10 This is a schematic diagram of a display panel provided in an embodiment of this disclosure. See also... Figure 10 The display panel includes a backlight module 10, an optical thin film 20, and a liquid crystal panel 30; the optical thin film 20 is located on the light-emitting surface of the backlight module 10, and the liquid crystal panel 30 is located on the optical thin film 20. The backlight module 10 can be... Figure 9 The backlight module 10 shown.
[0107] Figure 11 This is a flowchart illustrating a backlight module manufacturing method according to an embodiment of this disclosure. See also... Figure 11 The method includes the following steps: S11. Fabricate multiple light-emitting units, each light-emitting unit comprising multiple light-emitting diode chips spaced apart and a fluorescent layer covering the multiple light-emitting diode chips. The multiple light-emitting diode chips include at least one blue light-emitting diode chip and at least one green light-emitting diode chip, and the number of blue light-emitting diode chips is greater than or equal to the number of green light-emitting diode chips. The fluorescent layer is a red fluorescent layer.
[0108] S12. The plurality of light-emitting units are mounted on the circuit board, and the plurality of light-emitting units are evenly spaced on the circuit board.
[0109] In this embodiment, multiple light-emitting units are arranged on a circuit board as a backlight module. Each light-emitting unit includes a blue light-emitting diode chip and a green light-emitting diode chip. The blue light-emitting diode chip emits blue light, and the green light-emitting diode chip emits green light. Both blue and green light pass through a red phosphor layer and finally emit white light. Compared with the related technology that uses a blue light-emitting diode chip and a yellow phosphor layer to form white light, the above structure adds a green light-emitting diode chip and replaces the yellow phosphor with a red phosphor, so that the light-emitting unit constructs three independent and separate narrow spectral peaks of blue, green, and red light. This three-primary-color narrow-band light source structure significantly improves the color purity of each primary color compared with the continuous broadband mixed light in the related technology, greatly expanding the color gamut of the backlight module. It can achieve a color gamut coverage of over 100% NTSC, presenting richer and more realistic colors, and meeting the high requirements for color display in various complex scenarios. In addition, the number of blue light-emitting diode chips is greater than or equal to the number of green light-emitting diode chips. In addition to emitting blue light, blue light also excites red phosphors to produce red light. Therefore, having more or more blue light-emitting diode chips than green light-emitting diode chips can make the brightness of the three colors more balanced and synthesize pure white light.
[0110] Figure 12 This is a flowchart illustrating another backlight module manufacturing method provided in this disclosure. See also... Figure 12 The method includes the following steps: S21. Make multiple light-emitting units.
[0111] For example, step S21 may include: The first step is to provide a support, which includes a support cup and support pins. The support cup has a bowl-shaped structure. A reflective layer is electroplated on the bottom of the support cup.
[0112] In this embodiment of the disclosure, the bottom of the support bowl is embedded with support pins.
[0113] In this embodiment of the disclosure, the support may be made of composite polymer materials such as epoxy molding compound (EMC) or sheet molding compound (SMC).
[0114] For example, the support is made of EMC.
[0115] In this embodiment of the disclosure, the projection of the support bowl cup onto the circuit board can be circular or rectangular.
[0116] For example, the projection of the support bowl / cup onto the circuit board is circular.
[0117] In this embodiment, the support pins can be made of metals such as iron, copper, and steel, with a layer of nickel, silver, or gold plated on the surface.
[0118] For example, the support pins can be made of copper metal with a layer of nickel plated on the surface.
[0119] The second step is to fix the LED chip onto the bracket.
[0120] In this embodiment of the disclosure, the light-emitting unit includes two blue light-emitting diode chips and one green light-emitting diode chip, with the green light-emitting diode chip disposed between the two blue light-emitting diode chips.
[0121] In this implementation, a green light chip is located between two blue light chips, forming a BGB symmetrical structure. The green light can be uniformly mixed with the blue light on both sides, eliminating the blue-green light intensity ratio drift caused by changes in viewing angle. This suppresses the white light color temperature shift, improves the color temperature consistency of white light synthesis, and is conducive to achieving a more uniform light intensity distribution and color mixing.
[0122] In other embodiments, the light-emitting unit includes other numbers of blue light-emitting diode chips and green light-emitting diode chips, such as four blue light-emitting diode chips and two green light-emitting diode chips.
[0123] In other embodiments, other arrangements may be used, such as arranging a green LED chip, a blue LED chip, and a blue LED chip in sequence.
[0124] In this embodiment of the disclosure, the spacing between the two blue light-emitting diode chips and the one green light-emitting diode chip is equal.
[0125] In other embodiments, the spacing between the two blue LED chips and the green LED chip may also be unequal.
[0126] In this embodiment, the emission wavelength of the blue light-emitting diode chip can be 457.5~462.5nm. Using a blue light-emitting diode chip with the above wavelength can excite phosphors with a green light-emitting diode chip to form white light, greatly expanding the color gamut of the backlight module and improving its overall color gamut.
[0127] In this embodiment, the emission wavelength of the green light-emitting diode chip can be 520~526nm. Using a green light-emitting diode chip with the above wavelength can excite phosphors with a blue light-emitting diode chip to form white light, greatly expanding the color gamut of the backlight module and improving its overall color gamut.
[0128] In this embodiment of the disclosure, the driving current ratio of the blue light-emitting diode chip and the green light-emitting diode chip is 10:9.
[0129] In this implementation, the driving current ratio of the blue LED chip to the green LED chip is 10:9, resulting in low driving current and low power consumption. This allows the backlight module to be widely used in high-end TVs, monitor modules, and other fields.
[0130] For example, the driving current of the blue light-emitting diode chip is 40mA, and the driving current of the green light-emitting diode chip is 36mA.
[0131] The third step is to electrically connect the LED chip to the bracket pins using wires.
[0132] In this embodiment of the disclosure, the wire can be a metal wire such as silver, gold, copper or alloy.
[0133] For example, the wire is a copper metal wire.
[0134] In this embodiment, the conductor is a T-shaped arc with a tail. The T-shaped arc can effectively improve the conductor's resistance to breakage and increase the yield of the light-emitting diode. The connection method with the tail close to the ground can increase the contact area between the conductor and the bracket pin, thereby improving the stability of the light-emitting diode.
[0135] In this embodiment of the disclosure, the height of the T-shaped arc perpendicular to the direction of the circuit board is 110~135μm.
[0136] For example, the height of the T-shaped arc perpendicular to the circuit board direction is 120 μm.
[0137] In this embodiment of the disclosure, the length of the line tail can be 50~100μm.
[0138] For example, the length of the line tail can be 80 μm.
[0139] In other embodiments, the conductor may also be other types of arcs. For example, an M-shaped arc.
[0140] The fourth step is to apply fluorescent adhesive to the inside of the support bowl.
[0141] In this embodiment, the phosphor is a KSF red phosphor with an emission wavelength of 630-650 nm. Using KSF red phosphor ensures normal backlight brightness and improves the color gamut of the emitted white light.
[0142] For example, the phosphor is a KSF red phosphor with an emission wavelength of 631 nm.
[0143] In this embodiment, the height of the fluorescent layer in the direction perpendicular to the circuit board is 45~55μm less than the height of the support in the direction perpendicular to the circuit board.
[0144] For example, the height of the fluorescent layer in the direction perpendicular to the circuit board is less than the height of the support in the direction perpendicular to the circuit board by 50 μm.
[0145] In other embodiments, the height of the fluorescent layer in the direction perpendicular to the circuit board may also be greater than or equal to the height of the support in the direction perpendicular to the circuit board.
[0146] The fifth step involves gradient baking and curing of the mixture of phosphor and adhesive to form a fluorescent layer.
[0147] In this embodiment of the present disclosure, the product is first baked at a temperature of 55-65°C for 0.4-0.6 hours, then baked at a temperature of 95-105°C for 0.9-1.1 hours, and finally baked at a temperature of 145-155°C for 2.9-3.1 hours.
[0148] For example, the product is first baked at 60°C for 0.5 hours, then at 100°C for 1 hour, and finally at 150°C for 3 hours.
[0149] S22. The light-emitting unit is placed on the circuit board, and the light-emitting unit is electrically connected to the circuit board through a conductive material.
[0150] For example, step S22 may include: The first step is to place an appropriate amount of die bond adhesive on the circuit board.
[0151] In this embodiment of the disclosure, the die bond adhesive can be a milky white silicone resin.
[0152] In this embodiment of the disclosure, an appropriate amount of die bond adhesive is placed on the mounting position of the circuit board by means of printing or dispensing / spraying the valve body.
[0153] For example, an appropriate amount of die bond adhesive is applied to the mounting position on the circuit board by printing.
[0154] The second step is to place the light-emitting unit on the circuit board.
[0155] In this embodiment of the disclosure, the light-emitting unit is placed on the circuit board by a pick-and-place machine or a die bonder.
[0156] For example, the light-emitting unit is precisely placed on the circuit board using a pick-and-place machine.
[0157] The third step involves high-temperature curing to form an electrical pathway.
[0158] In this embodiment, the fixed light-emitting unit and circuit board are subjected to high-temperature curing treatment, so that the conductive material is cured at high temperature to form electrical conductivity, providing a stable foundation for subsequent reflow soldering.
[0159] The fourth step is to perform reflow soldering.
[0160] S23. Fix the capacitor, resistor, IC, and TVS diode onto the circuit board.
[0161] In this embodiment of the disclosure, capacitors, resistors, ICs, and TVS diodes are fixed on the circuit board using surface mount technology (SMT).
[0162] Capacitors, resistors, ICs, and TVS diodes are all electrically connected to the sub-circuit board.
[0163] Capacitors, resistors, ICs, and TVS diodes are located in the middle of two rows of sub-circuit boards.
[0164] Among them, capacitors are used to filter out high-frequency interference signals in the circuit, stabilize power supply voltage fluctuations, and store instantaneous electrical energy.
[0165] Resistors are used to limit the current in a circuit and to adjust the voltage division of a signal.
[0166] The IC is used to receive external control commands, analyze signals, and output precise drive signals. Since the backlight module is controlled by the IC, each lamp can be turned on or off as needed, resulting in high contrast. Furthermore, the dark areas are less prone to cross-contamination because the lamps are turned off. Additionally, the backlight module can independently control the blue and green LED chips, resulting in high color purity and vibrant colors.
[0167] TVS diodes are used to absorb sudden voltage surges in circuits (such as instantaneous high voltages caused by power plugging / unplugging or lightning strikes).
[0168] S24. Mount the lens, with the lens covering the LED chip.
[0169] In this embodiment of the disclosure, a lens is attached to the light-emitting diode chip using a lens attaching machine.
[0170] S25. Attach the LED chip to the backplate and assemble the reflective layer, diffuser plate and optical film in sequence.
[0171] In this embodiment, the diffuser plate can be made of silicone, epoxy resin, acrylic, or other materials. Silicone diffuser plates have excellent weather resistance and flexibility; epoxy resin diffuser plates have good mechanical strength and electrical insulation; acrylic diffuser plates have high light transmittance and are easy to process, and can be adjusted according to the uniformity of light emission.
[0172] For example, the diffuser plate is made of silicone.
[0173] In other embodiments, the liquid crystal panel can be assembled after step S25 to form a display panel.
[0174] This backlight module provides eye protection for display devices and can be used in devices such as tablets, laptops, monitors, and televisions.
[0175] Table 1 below shows the color gamut coverage of backlight modules provided by related technologies. In this table, R represents a red LED chip; G represents a green LED chip; and B represents a blue LED chip.
[0176] Table 1
[0177] As can be seen from Table 1, the color saturation and color gamut coverage of the backlight modules provided by the relevant technologies are relatively low.
[0178] Table 2 below shows the color gamut coverage of the backlight module provided in the embodiments of this disclosure. Wherein, R represents a red light-emitting diode chip; G represents a green light-emitting diode chip; and B represents a blue light-emitting diode chip.
[0179] Table 2
[0180] As can be seen from Table 2, the backlight module provided in this embodiment has high color saturation and color gamut coverage.
[0181] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.
Claims
1. A backlight module, characterized in that, The backlight module includes: a circuit board (101) and a plurality of light-emitting units (102), wherein the plurality of light-emitting units (102) are arranged at intervals on the circuit board (101) and are all electrically connected to the circuit board (101); Each of the light-emitting units (102) includes a plurality of light-emitting diode chips (203) spaced apart and a fluorescent layer (205) covering the plurality of light-emitting diode chips (203). The plurality of light-emitting diode chips (203) includes at least one blue light-emitting diode chip (2031) and at least one green light-emitting diode chip (2032), and the number of blue light-emitting diode chips (2031) is greater than or equal to the number of green light-emitting diode chips (2032). The fluorescent layer (205) is a red fluorescent layer.
2. The backlight module according to claim 1, characterized in that, The light-emitting unit (102) includes two blue light-emitting diode chips (2031) and one green light-emitting diode chip (2032), with the green light-emitting diode chip (2032) disposed between the two blue light-emitting diode chips (2031).
3. The backlight module according to claim 1 or 2, characterized in that, The blue light-emitting diode chip (2031) has an emission wavelength of 457.5~462.5nm, and the green light-emitting diode chip (2032) has an emission wavelength of 520~526nm.
4. The backlight module according to claim 1 or 2, characterized in that, The fluorescent layer (205) is a mixture of phosphor and adhesive, and the phosphor is KSF red phosphor with an emission wavelength of 630~650nm.
5. The backlight module according to claim 1 or 2, characterized in that, The spacing between two adjacent light-emitting units (102) is 30~50mm.
6. The backlight module according to claim 1 or 2, characterized in that, The driving current ratio of the blue light-emitting diode chip (2031) and the green light-emitting diode chip (2032) is 10:
9.
7. The backlight module according to claim 1 or 2, characterized in that, The circuit board (101) includes a plurality of sub-circuit boards (1001) and an adapter board (1002). The sub-circuit boards (1001) are arranged in an array, the sub-circuit boards (1001) extend along the row direction, and the adapter board (1002) extends along the column direction. The sub-circuit board (1001) includes an integrated circuit, and the integrated circuits of the plurality of sub-circuit boards (1001) are electrically connected to the adapter board (1002) respectively.
8. The backlight module according to claim 7, characterized in that, The light-emitting unit (102) further includes a positive electrode pin and two control pins. The positive electrode pin is electrically connected to the positive electrode of one of the blue light-emitting diode chips (2031) and the positive electrode of the green light-emitting diode chip (2032), respectively. One of the control pins is electrically connected to the negative electrode of one of the blue light-emitting diode chips (2031), the negative electrode of the green light-emitting diode chip (2032), and the positive electrode of another blue light-emitting diode chip (2031), respectively. The other control pin is electrically connected to the negative electrode of another blue light-emitting diode chip (2031). The positive pin is electrically connected to the adapter board (1002), and the two control pins are electrically connected to the integrated circuit.
9. The backlight module according to claim 8, characterized in that, The adapter board (1002) includes a connector and multiple connection interfaces. The connector is electrically connected to the multiple connection interfaces and the power board, respectively. The multiple connection interfaces are electrically connected to the integrated circuits of the multiple sub-circuit boards (1001).
10. A method for manufacturing a backlight module, characterized in that, The method includes: Multiple light-emitting units are fabricated. Each light-emitting unit includes multiple light-emitting diode chips spaced apart and a fluorescent layer covering the multiple light-emitting diode chips. The multiple light-emitting diode chips include at least one blue light-emitting diode chip and at least one green light-emitting diode chip, and the number of blue light-emitting diode chips is greater than or equal to the number of green light-emitting diode chips. The fluorescent layer is a red fluorescent layer. The plurality of light-emitting units are mounted on a circuit board, and the plurality of light-emitting units are evenly spaced on the circuit board.