Light-emitting device, backlight module and display panel

Abstract

The invention provides a light-emitting device, a backlight module and a display panel. The light-emitting device comprises a circuit board, a plurality of first light-emitting units and a plurality of second light-emitting units, wherein the first light-emitting units and the second light-emitting units are located on the circuit board; the first light-emitting unit comprises at least one purple light-emitting diode chip; the second light-emitting unit comprises at least two light-emitting diode chips and a fluorescent layer covering the at least two light-emitting diode chips, the at least two light-emitting diode chips comprise a blue light-emitting diode chip and a purple light-emitting diode chip, and the second light-emitting unit emits white light.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a light-emitting device, a backlight module and a display panel. Background Art

[0002] The backlight module is a device that provides light source in a display device.

[0003] The related art provides a backlight module, which includes a circuit board and a plurality of light-emitting units, and the plurality of light-emitting units are electrically connected to the circuit board. The light-emitting units include a blue light-emitting diode chip and phosphor, thereby emitting white light.

[0004] Related technology: The blue light spectrum in the light emitted by the above-mentioned backlight module has a relatively large energy, which can cause photochemical damage to the retina, accelerate oxidative damage to macular cells, and cause damage to the user's vision. Summary of the invention

[0005] The embodiments of the present disclosure provide a light emitting device, a backlight module and a display panel, which can reduce the spectral energy of blue light and play a role in eye protection. The technical solution is as follows:

[0006] In one aspect, a light emitting device is provided, the light emitting device comprising:

[0007] The light emitting device comprises: a circuit board, a plurality of first light emitting units and a plurality of second light emitting units, wherein the plurality of first light emitting units and the plurality of second light emitting units are both located on the circuit board;

[0008] The first light emitting unit comprises at least one purple light emitting diode chip;

[0009] The second light emitting unit includes at least two light emitting diode chips and a fluorescent layer covering the at least two light emitting diode chips, the at least two light emitting diode chips include a blue light emitting diode chip and a purple light emitting diode chip, and the second light emitting unit emits white light.

[0010] Optionally, the peak light emission wavelength of the purple light emitting diode chip of the first light emitting unit is in the range of 400-410 nm.

[0011] Optionally, the peak ranges of the emission wavelengths of the purple light emitting diode chip and the blue light emitting diode chip of the second light emitting unit are 400-410 nm and 457.5-465 nm respectively.

[0012] Optionally, the plurality of first light emitting units and the plurality of second light emitting units are arranged in a row on the circuit board, and the first light emitting units and the second light emitting units are arranged alternately.

[0013] Optionally, the first light-emitting unit includes two purple light-emitting diode chips, and the two purple light-emitting diode chips are connected in series.

[0014] Optionally, the second light-emitting unit includes one blue light-emitting diode chip and one purple light-emitting diode chip, and the blue light-emitting diode chip and the purple light-emitting diode chip are connected in series.

[0015] Optionally, the light emitting spectrum of the light emitting device has a first wavelength peak and a second wavelength peak, the first wavelength peak has a wavelength range of 390 to 420 nm, the second wavelength peak has a wavelength range of 435 to 475 nm, and the ratio of the relative value of the first wavelength peak to the relative value of the second wavelength peak is 4:1 to 6:1.

[0016] Optionally, the fluorescent layer is a mixture of fluorescent powder and glue, the fluorescent powder includes yellow fluorescent powder and red fluorescent powder, the yellow fluorescent powder is yellow powder with an emission wavelength of 545-555nm, and the red fluorescent powder is red powder with an emission wavelength of 620-640nm.

[0017] On the other hand, a backlight module is provided, which includes a light-emitting device and a current controller, wherein the light-emitting device is the above-mentioned light-emitting device, and the current controller is used to control the current of at least one first light-emitting unit according to the current of at least one second light-emitting unit, or to control the current of at least one second light-emitting unit according to the current of at least one first light-emitting unit.

[0018] In another aspect, a display panel is provided, the display panel comprising:

[0019] A backlight module and a liquid crystal panel; the liquid crystal panel is located on the light emitting surface of the backlight module.

[0020] The technical solution provided by the embodiments of the present disclosure brings the following beneficial effects:

[0021] In the disclosed embodiment, a plurality of first light-emitting units and a plurality of second light-emitting units are arranged on the circuit board as a backlight module. The second light-emitting unit includes at least two light-emitting diode chips, and the at least two light-emitting diode chips include a purple light-emitting diode chip and a blue light-emitting diode chip, and the two colors of chips emit white light. Compared with the related art that uses a blue light-emitting diode chip plus a fluorescent layer to form white light, the above-mentioned second light-emitting unit weakens the blue light spectrum energy in the emitted white light by adding a purple light-emitting diode chip. Moreover, the purple light spectrum energy of the second light-emitting unit is a certain multiple of the blue light under a certain current, thereby minimizing the blue light damage. However, since current fluctuations can easily make it difficult for the spectral energy of purple light to reach a certain multiple of blue light, a first light-emitting unit that only includes a purple light emitting diode chip is provided. By controlling the current of the first light-emitting unit, the spectral energy of purple light emitted by the first light-emitting unit is controlled, and the spectral energy of purple light of the second light-emitting unit is compensated, so that the spectral energy of purple light can reach a certain multiple of blue light again, which effectively reduces the photochemical damage to the retina caused by blue light and the oxidative damage to macular cells, reduces damage to the user's vision, and makes the backlight module and display device using the light-emitting device have an eye protection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 is a structural schematic diagram of a light-emitting device provided by an embodiment of the present disclosure;

[0024] Figure 2 is a schematic structural diagram of a first light-emitting unit provided in an embodiment of the present disclosure;

[0025] Figure 3 is a schematic structural diagram of a second light-emitting unit provided in an embodiment of the present disclosure;

[0026] Figure 4 is a structural schematic diagram of a backlight module provided by an embodiment of the present disclosure;

[0027] Figure 5 is a top view of the structure of an edge-type backlight module provided by an embodiment of the present disclosure;

[0028] Figure 6 is a top view of the structure of a direct-type backlight module provided by an embodiment of the present disclosure;

[0029] Figure 7is a schematic diagram of a display panel provided by an embodiment of the present disclosure;

[0030] Figure 8 is a flow chart of a method for preparing a light-emitting device provided by an embodiment of the present disclosure;

[0031] Fig. 9 is a flow chart of a method for preparing a backlight module provided by an embodiment of the present disclosure;

[0032] Fig.10 is a structural schematic diagram of a first light-emitting unit in a process of manufacturing a backlight module provided by an embodiment of the present disclosure;

[0033] Fig.11 is a schematic structural diagram of a second light-emitting unit in a process of manufacturing a backlight module provided by an embodiment of the present disclosure;

[0034] Fig.12 is a schematic diagram of a backlight module circuit provided by an embodiment of the present disclosure;

[0035] Fig.13 is a spectrum diagram of a light-emitting unit after passing through a light guide plate provided by an embodiment of the present disclosure;

[0036] Fig.14 It is a spectrum diagram of a light emitting unit light after passing through a light guide plate, a diffusion plate and a liquid crystal panel provided by an embodiment of the present disclosure;

[0037] Fig.15 It is a spectrum diagram of a light-emitting unit provided by the related technology after ordinary blue light source plus phosphor light passes through the light guide plate, diffuser plate and liquid crystal panel;

[0038] Fig.16 It is a spectrum diagram of the blue light and purple light bands under different currents provided by the embodiments of the present disclosure.

[0039] The reference numerals are as follows:

[0040] 100: back plate 101: circuit board; 102: first light emitting unit; 103: second light emitting unit; 104: current controller; 105: light guide plate; 106: diffusion plate; 107: reflection layer;

[0041] 201: bracket; 202: bracket pin; 203: light emitting diode chip; 204: wire; 205: fluorescent layer; 206: silicone layer;

[0042] 1031: the first TVS tube; 1032: the second TVS tube;

[0043] 2031: purple light emitting diode chip; 2032: blue light emitting diode chip;

[0044] 1: anode of the first light-emitting unit; 2: cathode of the first light-emitting unit; 3: anode of the second light-emitting unit; 4: cathode of the second light-emitting unit;

[0045] 10: backlight module; 20: LCD panel. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0047] In the related art, a conventional structured LED is used which uses a blue light chip with a wavelength of 447.5 to 455 nm and phosphor to excite the blue light to form white light. The blue light with a wavelength of 447.5 to 455 nm is very harmful to the human eye.

[0048] Figure 1 is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Figure 1 The light emitting device includes: a circuit board 101, a plurality of first light emitting units 102 and a plurality of second light emitting units 103, wherein the plurality of first light emitting units 102 and the plurality of second light emitting units 103 are both located on the circuit board 101.

[0049] Figure 2 is a schematic diagram of the structure of the first light-emitting unit provided in the embodiment of the present disclosure. Figure 2 , the first light emitting unit 102 includes at least one purple light emitting diode chip 2031 .

[0050] Figure 3 is a schematic diagram of the structure of the second light-emitting unit provided in the embodiment of the present disclosure. Figure 3 The second light-emitting unit 103 includes at least two light-emitting diode chips 203 and a fluorescent layer 205 covering the at least two light-emitting diode chips 203, the at least two light-emitting diode chips 203 include a blue light-emitting diode chip 2032 and a purple light-emitting diode chip 2031, and the second light-emitting unit 103 emits white light.

[0051] In the disclosed embodiment, a plurality of first light-emitting units and a plurality of second light-emitting units are arranged on the circuit board as a backlight module. The second light-emitting unit includes at least two light-emitting diode chips, and the at least two light-emitting diode chips include a purple light-emitting diode chip and a blue light-emitting diode chip, and the two colors of chips emit white light. Compared with the related art that uses a blue light-emitting diode chip plus a fluorescent layer to form white light, the above-mentioned second light-emitting unit weakens the blue light spectrum energy in the emitted white light by adding a purple light-emitting diode chip. Moreover, the purple light spectrum energy of the second light-emitting unit is a certain multiple of the blue light under a certain current, thereby minimizing the blue light damage. However, since current fluctuations can easily make it difficult for the spectral energy of purple light to reach a certain multiple of blue light, a first light-emitting unit that only includes a purple light emitting diode chip is provided. By controlling the current of the first light-emitting unit, the spectral energy of purple light emitted by the first light-emitting unit is controlled, and the spectral energy of purple light of the second light-emitting unit is compensated, so that the spectral energy of purple light can reach a certain multiple of blue light again, which effectively reduces the photochemical damage to the retina caused by blue light and the oxidative damage to macular cells, reduces damage to the user's vision, and makes the backlight module and display device using the light-emitting device have an eye protection effect.

[0052] In the embodiment of the present disclosure, the peak wavelength range of the light emission of the purple light emitting diode chip 2031 of the first light emitting unit 102 is 400-410 nm.

[0053] In the embodiment of the present disclosure, the peak ranges of the emission wavelengths of the purple light emitting diode chip 2031 and the blue light emitting diode chip 2032 of the second light emitting unit 103 are 400-410 nm and 457.5-465 nm, respectively.

[0054] In the disclosed embodiment, the blue light emitting diode chip with the above wavelength can excite the phosphor with the purple light emitting diode chip to form white light, and the spectral energy of the blue light is weakened, which plays a role in protecting the eyes. In addition, compared with the 447.5-455nm blue light in the related art, the 457.5-465nm blue light reduces the blue light hazard.

[0055] In the embodiment of the present disclosure, the light spectrum of the light emitting device assembled with the first light emitting unit 102 and the second light emitting unit 103 has a first wavelength peak and a second wavelength peak, the first wavelength peak wavelength ranges from 390 to 420 nm, the second wavelength peak wavelength ranges from 435 to 475 nm, and the ratio of the first wavelength peak relative value to the second wavelength peak relative value is 4: 1 to 6: 1. The blue light of the backlight module using the above ratio is mostly absorbed and weakened to less than one-fifth of the spectrum, which plays a role in eye protection.

[0056] Exemplarily, the ratio of the first wavelength peak relative value to the second wavelength peak relative value is 5:1.

[0057] See again Figure 1 , a plurality of first light emitting units 102 and a plurality of second light emitting units 103 are arranged in a row on the circuit board 101, and this arrangement of the backlight module is suitable for an edge-entry backlight source. The first light emitting units 102 and the second light emitting units 103 are arranged alternately. Alternating the first light emitting units and the second light emitting units can make the purple light in the first light emitting unit better compensate for the blue light spectrum energy in the second light emitting unit, ensure that the energy ratio of the blue-purple light is maintained at the required multiple, and make the light output of the backlight module more uniform.

[0058] In other implementations, the plurality of first light-emitting units 102 and the plurality of second light-emitting units 103 may also be arranged in a plurality of rows, which is suitable for a direct-type backlight source.

[0059] like Figure 1 As shown, the light emitting device further includes: a first transient voltage suppressor diode (Transient Voltage Suppressor, TVS) 1031 and a second TVS diode 1032;

[0060] The first TVS tube 1031 is connected in parallel with the plurality of first light-emitting units 102 , and the second TVS tube 1032 is connected in parallel with the plurality of second light-emitting units 103 .

[0061] In the disclosed embodiment, the light-emitting unit can protect the circuit from large current shocks by being connected in parallel with the TVS tube, thereby improving the stability of the backlight module.

[0062] In the disclosed embodiment, the first light emitting unit 102 includes two purple light emitting diode chips 2031, which are connected in series. The two purple light emitting diodes can make the first light emitting unit emit purple light to compensate for the purple light spectrum energy in the second light emitting unit, ensuring that the energy ratio of blue-purple light is maintained at the required multiple without requiring too many LED chips to increase the cost.

[0063] In other embodiments, the first light emitting unit 102 includes at least three purple LED chips 2031 .

[0064] In the disclosed embodiment, the second light emitting unit 103 includes a blue light emitting diode chip 2032 and a purple light emitting diode chip 2031, and the blue light emitting diode chip 2032 and the purple light emitting diode chip 2031 are connected in series. The blue light emitting diode chip and the purple light emitting diode chip can emit white light to reduce the blue light spectrum energy, and only one blue light emitting diode chip 2032 and one purple light emitting diode chip 2031 are provided, and the cost is sufficiently low.

[0065] In other embodiments, the second light emitting unit 103 includes at least two blue light emitting diode chips 2032 and at least two purple light emitting diode chips 2031 .

[0066] In the disclosed embodiment, the first light-emitting unit 102 further includes a silicone layer 206, which covers at least one purple LED chip 2031. The silicone layer can protect the purple LED chip and will not affect the purple light spectrum energy emitted by the purple LED chip.

[0067] In the disclosed embodiment, the fluorescent layer 205 in the second light-emitting unit 103 is a mixture of fluorescent powder and glue, and the fluorescent powder includes yellow fluorescent powder and red fluorescent powder. The yellow fluorescent powder is a yellow powder with an emission wavelength of 545 to 555 nm, and the red fluorescent powder is a red powder with an emission wavelength of 620 to 640 nm. The use of yellow fluorescent powder and red fluorescent powder of the above wavelengths can achieve white light output of the second light-emitting unit, and reduce the blue light spectrum energy to meet the requirements of eye protection.

[0068] In the embodiment of the present disclosure, the phosphor layer 205 in the second light emitting unit 103 has a phosphor content of 15-30%. The phosphor content in the above ratio can ensure normal backlight brightness and purer white light.

[0069] Exemplarily, the phosphor accounts for 20%.

[0070] In the embodiment of the present disclosure, the circuit board 101 may be a flexible printed circuit (FPC).

[0071] In the embodiment of the present disclosure, the first light emitting unit 102 and the second light emitting unit 103 further include a bracket 201, a bracket pin 202 and a wire 204;

[0072] The LED chips 203 are electrically connected to the bracket pins 202 on the bracket pins 202 , the LED chips 203 are electrically connected to each other through the wires 204 , and the LED chips 203 on both sides are electrically connected to the bracket pins 202 through the wires 204 .

[0073] In this implementation, the light-emitting unit can arrange multiple light-emitting diode chips together through a bracket and protect the light-emitting diodes; electrical connections are made through pins and wires to form good electrical conduction.

[0074] In the disclosed embodiment, the material of the bracket 201 can be made of composite polymer materials such as polyphthalamide (PPA), polycyclohexylenedimethylene terephthalate (PCT), epoxy molding compound (EMC) and sheet molding compound (SMC).

[0075] Exemplarily, the material of the bracket 201 is PPA.

[0076] In the disclosed embodiment, the shape of the bracket 201 is a circular bowl.

[0077] In the disclosed embodiment, the diameter of the bowl of the bracket 201 may be 0.5-0.7 mm.

[0078] Exemplarily, the diameter of the bowl of the support 201 is 0.6 mm.

[0079] In the disclosed embodiment, the material of the bracket pin 202 can be made of a metal such as iron, copper, steel, etc., and then electroplated with a layer of nickel, silver, gold, etc.

[0080] Exemplarily, the material of the bracket pin 202 can be made of a copper metal surface and then electroplated with a layer of nickel material.

[0081] In the disclosed embodiment, the wire 204 may be a metal wire such as silver, gold, copper or alloy.

[0082] Exemplarily, the wire 204 is a copper metal wire.

[0083] In the embodiment of the present disclosure, the wire 204 connecting the two LED chips 203 is an M-shaped arc. The M-shaped arc can effectively improve the anti-fracture capability of the wire between the two LED chips and improve the yield of the LED.

[0084] In the embodiment of the present disclosure, the wire 204 connecting the LED chip 203 and the bracket pin 202 is a T-shaped arc. The T-shaped arc can effectively improve the anti-fracture ability of the wire between the LED chip and the bracket pin, and improve the yield of the LED.

[0085] Optionally, the T-shaped arc is welded to the bracket pin by the wire tail touching the ground, that is, the welding area between the T-shaped arc and the bracket pin is increased. The wire tail touching the ground connection method can increase the contact area between the wire and the bracket pin and improve the stability of the light-emitting diode.

[0086] Exemplarily, the diameter of the welding point between the T-shaped arc and the bracket pin is 30-100 mm, for example, 55 mm.

[0087] In the embodiment of the present disclosure, the emission wavelength of the purple light emitting diode chip 2031 may be 400-410 nm. The purple light emitting diode chip with the above wavelength can weaken the spectrum energy of the blue light emitted by the blue light emitting diode chip, thus playing a role in protecting the eyes.

[0088] Figure 4 Schematic diagram of the structure of a backlight module provided by an embodiment of the present disclosure. Figure 4 The backlight module also includes: a current controller 104, which is used to obtain the detected current of the second light-emitting unit 103; based on the corresponding relationship between the current of the second light-emitting unit 103 and the current of the first light-emitting unit 102, determine the current of the first light-emitting unit 102 corresponding to the current of the second light-emitting unit 103; and use the determined current of the first light-emitting unit 102 to control the first light-emitting unit 102.

[0089] In this implementation, by acquiring the detected current of the second light-emitting unit, which can reflect the multiple relationship between the purple light spectrum energy and the blue light spectrum energy in the light currently emitted by the second light-emitting unit, and controlling the current of the first light-emitting unit to perform purple light compensation based on the current correspondence, the multiple relationship between the purple light spectrum energy and the blue light spectrum energy emitted by the first light-emitting unit and the second light-emitting unit can be better controlled in different current environments, thereby achieving an eye protection effect.

[0090] Exemplarily, the current controller 104 may include a current detection unit, a calculation unit, and a current control unit. The current detection unit is used to detect the current of the second light-emitting unit 103; the calculation unit is used to determine the current of the first light-emitting unit 102 corresponding to the current of the second light-emitting unit 103; and the current control unit is used to control the current of the first light-emitting unit 102.

[0091] The current controller 104 may be implemented using an integrated circuit or a chip.

[0092] Figure 5 is a top view of the structure of an edge-lit backlight module provided by an embodiment of the present disclosure. Figure 5 The backlight module may further include a light guide plate 105 and a diffuser plate 106 ; the light emitting surfaces of the plurality of first light emitting units 102 and the plurality of second light emitting units 103 face the light incident surface of the light guide plate 105 , and the diffuser plate 106 is located on the light emitting surface of the light guide plate 105 .

[0093] In this implementation, the side-entry backlight source is realized by a light guide plate. The side-entry structured light is emitted from the side, which can reduce the thickness of the backlight module and can be applied to tablets, mobile phones, learning machines, educational machines, displays and other fields.

[0094] In the embodiment of the present disclosure, the material of the light guide plate 105 can be a light guide plate made of polymethyl methacrylate, polycarbonate or polystyrene.

[0095] Exemplarily, the light guide plate 105 may be a light guide plate made of polymethyl methacrylate.

[0096] In the embodiment of the present disclosure, the second light-emitting unit 103 composed of the purple light-emitting diode chip 2031 and the blue light-emitting diode chip 2032 in the second light-emitting unit 103 emits light with an energy ratio of 2 to 4: 1. The blue light of the second light-emitting unit with the above ratio is mostly absorbed and weakened, which plays a role in protecting the eyes.

[0097] When the current of the second light emitting unit 103 makes the energy ratio of the purple light spectrum to the blue light spectrum 4:1, there is no need to compensate through the first light emitting unit 102, and the current of the first light emitting unit 102 can be controlled to be 0 at this time.

[0098] When the current of the second light emitting unit 103 makes the energy ratio of the purple light spectrum to the blue light spectrum smaller, the current of the first light emitting unit 102 is controlled to be larger, thereby compensating the energy of the purple light spectrum to the blue light spectrum to 4-5:1.

[0099] In the embodiment of the present disclosure, the current of the second light emitting unit 103 is controlled to be 0-300 mA, the current of the first light emitting unit 102 is controlled to be 0-500 mA, and the current is adjustable within the range.

[0100] For example, when the current of the second light-emitting unit 103 is A, the corresponding relationship determines that the current of the first light-emitting unit 102 needs to be controlled to be B, then at this time, the sum of the spectral energy of the purple light emitted by the second light-emitting unit 103 and the purple light emitted by the first light-emitting unit 102 and the spectral energy ratio of the blue light emitted by the second light-emitting unit 103 meet the requirements. A is selected within 0 to 300 mA, and B is selected within 0 to 500 mA.

[0101] Figure 6 is a top view of the structure of a direct-type backlight module provided by an embodiment of the present disclosure. Figure 6 The backlight module may further include a diffusion plate 106 .

[0102] The plurality of first light emitting units 102 and the plurality of second light emitting units 103 are located between the diffusion plate 106 and the circuit board 101 .

[0103] The direct-down structure described above is adopted, because the direct-down structure does not have a light guide plate, thereby reducing energy loss in the light refraction process.

[0104] In the embodiment of the present disclosure, the material of the diffusion plate 106 can be a diffusion plate made of silicone, epoxy resin, acrylic material, etc.

[0105] Exemplarily, the material of the diffusion plate 106 is silica gel.

[0106] See again Figure 6 The backlight module may further include a back plate 100 and a reflective layer 107 , the circuit board 101 is on the back plate 100 , and the reflective layer 107 covers the back plate 100 and the circuit board 101 .

[0107] In the embodiment of the present disclosure, the back plate 100 may be a metal back plate, for example, a metal back plate that can be stamped by a punching die.

[0108] Figure 7 is a schematic diagram of a display panel provided by an embodiment of the present disclosure. Figure 7 The display panel includes: a backlight module 10 and a liquid crystal panel 20; the liquid crystal panel 20 is located on the light emitting surface of the backlight module 10. The backlight module 10 can be Figures 4 to 6 The backlight module 10 shown in any one of the figures.

[0109] Figure 8 is a flow chart of a method for preparing a light emitting device provided by an embodiment of the present disclosure. Figure 8 The method steps include:

[0110] S11, manufacturing a plurality of first light-emitting units and a plurality of second light-emitting units.

[0111] S12. Install multiple light-emitting units on a circuit board, and connect multiple first light-emitting units in series, and multiple second light-emitting units in series, the first light-emitting unit includes at least one purple light-emitting diode chip, the second light-emitting unit includes at least two light-emitting diode chips, the at least two light-emitting diode chips include a blue light-emitting diode chip and a purple light-emitting diode chip, and the second light-emitting unit emits white light.

[0112] In the disclosed embodiment, a plurality of first light-emitting units and a plurality of second light-emitting units are arranged on the circuit board as a backlight module. The second light-emitting unit includes at least two light-emitting diode chips, and the at least two light-emitting diode chips include a purple light-emitting diode chip and a blue light-emitting diode chip, and the two colors of chips emit white light. Compared with the related art that uses a blue light-emitting diode chip plus a fluorescent layer to form white light, the above-mentioned second light-emitting unit weakens the blue light spectrum energy in the emitted white light by adding a purple light-emitting diode chip. Moreover, the purple light spectrum energy of the second light-emitting unit is a certain multiple of the blue light under a certain current, thereby minimizing the blue light damage. However, since current fluctuations can easily make it difficult for the spectral energy of purple light to reach a certain multiple of blue light, a first light-emitting unit that only includes a purple light emitting diode chip is provided. By controlling the current of the first light-emitting unit, the spectral energy of purple light emitted by the first light-emitting unit is controlled, and the spectral energy of purple light of the second light-emitting unit is compensated, so that the spectral energy of purple light can reach a certain multiple of blue light again, which effectively reduces the photochemical damage to the retina caused by blue light and the oxidative damage to macular cells, reduces damage to the user's vision, and makes the display device using the light-emitting device and backlight module have an eye protection effect.

[0113] Fig. 9 is a flow chart of a method for preparing a backlight module provided by an embodiment of the present disclosure. Fig. 9 The method steps include:

[0114] S21. Provide a bracket.

[0115] In the disclosed embodiment, the material of the bracket can be made of composite polymer materials such as PPA, PCT, EMC and SMC.

[0116] Exemplarily, the material of the bracket is PPA.

[0117] In the disclosed embodiment, the bracket is shaped like a circular bowl.

[0118] In the disclosed embodiment, the diameter of the bracket bowl may be 0.5 to 0.7 mm.

[0119] Exemplarily, the diameter of the support cup is 0.6 mm.

[0120] In the disclosed embodiment, the bracket is grooved on the carrier material by laser to obtain a circular bowl-shaped structure.

[0121] S22. Make bracket pins on the bracket.

[0122] In the disclosed embodiment, the material of the bracket pin can be made of a metal such as iron, copper, steel, etc., and then electroplated with a layer of nickel, silver, gold, etc.

[0123] Exemplarily, the material of the bracket pin can be made of a copper metal surface electroplated with a layer of nickel material.

[0124] S23, installing a light-emitting diode chip, and electrically connecting the light-emitting diode chip to the bracket pins.

[0125] Fig.10 FIG. 1 is a schematic diagram of the structure of the first light-emitting unit in the process of manufacturing the backlight module provided by the embodiment of the present disclosure. Fig.10 The purple light emitting diode chip 2031 is electrically connected to the support pin 202 on the support pin 202 .

[0126] Fig.11 FIG. 1 is a schematic diagram of the structure of the second light-emitting unit in the backlight module manufacturing process provided by the embodiment of the present disclosure. Fig.11 The LED chip 203 includes a purple LED chip 2031 and a blue LED chip 2032 , and the LED chip 203 is electrically connected to the bracket pin 202 on the bracket pin 202 .

[0127] In the embodiment of the present disclosure, the peak light emission wavelength range of the purple light emitting diode chip of the first light emitting unit is 400-410 nm.

[0128] In the embodiment of the present disclosure, the peak ranges of the emission wavelengths of the purple light emitting diode chip and the blue light emitting diode chip of the second light emitting unit are 400-410 nm and 457.5-465 nm, respectively.

[0129] In the disclosed embodiment, the blue light emitting diode chip with the above wavelength can excite the phosphor with the purple light emitting diode chip to form white light, and the spectral energy of the blue light is weakened, which plays a role in protecting the eyes. In addition, compared with the 447.5-455nm blue light in the related art, the 457.5-465nm blue light reduces the blue light hazard.

[0130] In the disclosed embodiment, the light spectrum of the light emitting device assembled with the first light emitting unit and the second light emitting unit has a first wavelength peak and a second wavelength peak, the first wavelength peak wavelength ranges from 390 to 420 nm, the second wavelength peak wavelength ranges from 435 to 475 nm, and the ratio of the first wavelength peak relative value to the second wavelength peak relative value is 4:1 to 6:1. The blue light of the backlight module using the above ratio is mostly absorbed and weakened to less than one-fifth of the spectrum, which plays a role in eye protection.

[0131] Exemplarily, the ratio of the first wavelength peak relative value to the second wavelength peak relative value is 5:1.

[0132] In the embodiment of the present disclosure, the second light-emitting unit composed of the purple light-emitting diode chip and the blue light-emitting diode chip emits light with an energy ratio of 2 to 4: 1. The blue light of the second light-emitting unit with the above ratio is mostly absorbed and weakened, which plays a role in eye protection.

[0133] When the current of the second light emitting unit makes the energy ratio of the purple light spectrum to the blue light spectrum be 4:1, there is no need to compensate by the first light emitting unit, and the current of the first light emitting unit 102 can be controlled to be 0 at this time.

[0134] When the current of the second light emitting unit makes the energy ratio of the purple light spectrum to the blue light spectrum smaller, the current of the first light emitting unit is controlled to be larger, thereby compensating the energy of the purple light spectrum to the blue light spectrum to 4:1 to 6:1.

[0135] In the embodiment of the present disclosure, the current of the second light emitting unit is controlled to be 0-300 mA, the current of the first light emitting unit is controlled to be 0-500 mA, and the current is adjustable within the range.

[0136] For example, when the current of the second light-emitting unit is A, the corresponding relationship determines that the current of the first light-emitting unit needs to be controlled to be B. At this time, the spectral energy ratio of the sum of the spectral energy of the purple light emitted by the second light-emitting unit and the purple light emitted by the first light-emitting unit to the spectral energy ratio of the blue light emitted by the second light-emitting unit meets the requirements. A is selected within 0 to 300 mA, and B is selected within 0 to 500 mA.

[0137] Exemplarily, the light-emitting diode chip tube is fixed to the bracket pin by a spot flux eutectic method.

[0138] S24, making wires, the light-emitting diode chips are electrically connected to each other through the wires, and the light-emitting diode chips on both sides are electrically connected to the bracket pins through the wires.

[0139] In the disclosed embodiment, a wire bonding machine is used to bond metal wires to chip electrodes and brackets under the action of temperature, pressure, and ultrasound.

[0140] In the embodiment of the present disclosure, the conductive wire may be a metal wire such as silver, gold, copper or an alloy.

[0141] Exemplarily, the conductive wire is a copper metal wire.

[0142] In the embodiment of the present disclosure, the wire connecting the two LED chips is an M-shaped arc. The M-shaped arc can effectively improve the anti-fracture capability of the wire between the two LED chips and improve the yield rate of the LED.

[0143] In the embodiment of the present disclosure, the wire connecting the LED chip and the bracket pin is a T-shaped arc. The T-shaped arc can effectively improve the fracture resistance of the LED chip and the bracket pin wire and improve the yield of the LED.

[0144] Optionally, the T-shaped arc is welded to the bracket pin by the wire tail touching the ground, that is, the welding area between the T-shaped arc and the bracket pin is increased. The wire tail touching the ground connection method can increase the contact area between the wire and the bracket pin and improve the stability of the light-emitting diode.

[0145] Exemplarily, the diameter of the welding point between the T-shaped arc and the bracket pin is 30-100 mm, for example, 55 mm.

[0146] S25, manufacturing a colloidal layer in the first light-emitting unit and a fluorescent layer in the second light-emitting unit, wherein the colloidal layer and the fluorescent layer are located in the bracket and cover the light-emitting diode chip.

[0147] In the embodiment of the present disclosure, the colloidal layer in the first light-emitting unit is a methyl silica gel layer, and the fluorescent layer in the second light-emitting unit is a mixture layer of yellow fluorescent powder, red fluorescent powder and glue.

[0148] In the embodiment of the present disclosure, the phosphor layer in the second light-emitting unit has a phosphor content of 15-30%. The phosphor content in the above ratio can ensure normal backlight brightness and purer white light.

[0149] Exemplarily, the phosphor accounts for 20%.

[0150] In the disclosed embodiment, the fluorescent layer in the second light-emitting unit is a mixture of fluorescent powder and glue, the fluorescent powder includes yellow fluorescent powder and red fluorescent powder, the yellow fluorescent powder is yellow powder with an emission wavelength of 545 to 555 nm, and the red fluorescent powder is red powder with an emission wavelength of 620 to 640 nm. The yellow fluorescent powder and red fluorescent powder of the above wavelengths can achieve white light output and reduce the blue light spectrum energy to meet the requirements of eye protection.

[0151] S26, connecting the first light emitting unit and the second light emitting unit to the circuit board to form an electrical path.

[0152] The circuit board also has a first TVS tube and a second TVS tube. After the first light-emitting unit and the second light-emitting unit are arranged, the first light-emitting unit is connected in parallel with the first TVS tube, and the second light-emitting unit is connected in parallel with the second TVS tube.

[0153] In the embodiment of the present disclosure, the light-emitting unit can protect the circuit from large current shocks by being connected in parallel with the TVS tube, thereby improving the stability of the light-emitting diode.

[0154] Exemplarily, step S26 may include:

[0155] The first step is to place an appropriate amount of conductive material onto the pins of the circuit board.

[0156] In the embodiment of the present disclosure, the conductive material may be silver glue, solder paste, etc.

[0157] Exemplarily, the conductive material may be solder paste.

[0158] In the disclosed embodiment, a suitable amount of conductive material is placed at the mounting position of the circuit board by printing or spraying the dispensing valve body.

[0159] Exemplarily, a suitable amount of conductive material is placed at the mounting position of the circuit board by printing.

[0160] In the second step, high temperature curing forms an electrical path.

[0161] In the embodiment of the present disclosure, the first light emitting unit and the second light emitting unit are fixed to the mounting position of the circuit board by a chip mounter or a die bonder.

[0162] Exemplarily, the first light-emitting unit and the second light-emitting unit are fixed to the mounting position of the circuit board by a placement machine.

[0163] In other embodiments, the light emitting unit may also be formed on a circuit board by means of Chips on Board packaging.

[0164] In the disclosed embodiment, a plurality of first light-emitting units and a plurality of second light-emitting units are arranged in a row on a circuit board, and such a backlight module is suitable for an edge-entry backlight source. The first light-emitting units and the second light-emitting units are arranged alternately. Alternating the first light-emitting units and the second light-emitting units can make the purple light in the first light-emitting units better compensate for the blue light spectrum energy in the second light-emitting units, ensure that the energy ratio of the blue-purple light is maintained at a required multiple, and make the light output of the backlight module more uniform.

[0165] In the disclosed embodiment, the first light-emitting unit includes two purple light-emitting diode chips, which are connected in series. The two purple light-emitting diodes can make the first light-emitting unit emit purple light to compensate for the purple light spectrum energy in the second light-emitting unit, ensuring that the energy ratio of blue-purple light is maintained at the required multiple without requiring too many LED chips to increase costs.

[0166] In other embodiments, the first light emitting unit includes at least three purple light emitting diode chips.

[0167] In the disclosed embodiment, the second light emitting unit includes a blue light emitting diode chip and a purple light emitting diode chip, which are connected in series. The blue light emitting diode chip and the purple light emitting diode chip can emit white light to reduce the blue light spectrum energy, and only one blue light emitting diode chip and one purple light emitting diode chip are provided, so the cost is sufficiently low.

[0168] In other embodiments, the second light emitting unit includes at least two blue light emitting diode chips and at least two purple light emitting diode chips.

[0169] The third step is to perform reflow soldering.

[0170] In the embodiment of the present disclosure, the mounted first light-emitting unit and the second light-emitting unit are fixed to the circuit board by soldering with solder paste.

[0171] S27. Electrically connect the circuit board to the current controller.

[0172] In the embodiment of the present disclosure, the current controller may be integrated on a circuit board.

[0173] In other embodiments, the current controller may also be provided separately and then connected to the circuit board.

[0174] In the embodiment of the present disclosure, the current controller is used to obtain the detected current of the second light-emitting unit; based on the corresponding relationship between the current of the second light-emitting unit and the current of the first light-emitting unit, determine the current of the first light-emitting unit corresponding to the current of the second light-emitting unit; and use the determined current of the first light-emitting unit to control the first light-emitting unit.

[0175] In this implementation, by acquiring the detected current of the second light-emitting unit, which can reflect the multiple relationship between the purple light spectrum energy and the blue light spectrum energy in the light currently emitted by the second light-emitting unit, and controlling the current of the first light-emitting unit to perform purple light compensation based on the current correspondence, the multiple relationship between the purple light spectrum energy and the blue light spectrum energy emitted by the first light-emitting unit and the second light-emitting unit can be better controlled in different current environments, thereby achieving an eye protection effect.

[0176] Exemplarily, the current controller may include a current detection unit, a calculation unit, and a current control unit. The current detection unit is used to detect the current of the second light-emitting unit; the calculation unit is used to determine the current of the first light-emitting unit corresponding to the current of the second light-emitting unit; and the current control unit is used to control the current of the first light-emitting unit.

[0177] The current controller can be implemented using an integrated circuit or a chip.

[0178] Fig.12 Schematic diagram of the backlight module circuit provided by the embodiment of the present disclosure. Fig.12 shown.

[0179] Multiple first light-emitting units 102 are connected in series, and current flows out from the anode 1 of the first light-emitting unit 102 , passes through the first light-emitting unit 102 , and flows to the cathode 2 of the first light-emitting unit. A first TVS tube 1031 is connected in parallel at both ends of the multiple first light-emitting units 102 .

[0180] Multiple second light-emitting units 103 are connected in series, and current flows out from the anode 3 of the second light-emitting unit 103 , passes through the second light-emitting unit 103 , and flows to the cathode 4 of the second light-emitting unit 103 . A second TVS tube 1032 is connected in parallel at both ends of the multiple second light-emitting units 103 .

[0181] S28, assembling the light guide plate and the diffusion plate.

[0182] Wherein, a plurality of first light-emitting units, a plurality of second light-emitting units and a TVS tube are located on the side surface of the light guide plate, and a diffusion plate is located on the light emitting surface of the light guide plate.

[0183] In the embodiment of the present disclosure, the material of the light guide plate may be a light guide plate made of polymethyl methacrylate, polycarbonate or polystyrene.

[0184] Exemplarily, the light guide plate may be a light guide plate made of polymethyl methacrylate.

[0185] In the disclosed embodiment, the material of the diffuser plate can be a diffuser plate made of silicone, epoxy resin, acrylic material, etc. The silicone diffuser plate has excellent weather resistance and flexibility; the epoxy resin diffuser plate has good mechanical strength and electrical insulation; the acrylic diffuser plate has high light transmittance and easy processing characteristics, and can be adjusted according to the uniformity of light emission.

[0186] Exemplarily, the material of the diffusion plate is silica gel.

[0187] Fig.13 is a spectrum diagram of a light-emitting unit after passing through a light guide plate provided by an embodiment of the present disclosure; Fig.14 It is a spectrum diagram of a light emitting unit light after passing through a light guide plate, a diffusion plate and a liquid crystal panel provided by an embodiment of the present disclosure; Fig.15 It is a spectrum diagram of a light-emitting unit provided by related technology, which is a common blue light source plus phosphor light after passing through a light guide plate, a diffusion plate and a liquid crystal panel.

[0188] refer to Figures 13-15, the horizontal axis is wavelength, in nanometers; the vertical axis is spectral visual efficiency. It can be clearly seen that compared with the backlight module provided by the related art, the blue light spectral visual efficiency of the backlight module provided by the embodiment of the present disclosure is significantly reduced after passing through the light guide plate, the diffuser plate and the liquid crystal panel, which can weaken the spectral energy of the blue light, effectively reduce the photochemical damage caused by the blue light to the retina and the oxidative damage to the macular cells, and reduce the damage to the user's vision.

[0189] The display device of the backlight module has an eye protection effect and can be applied to devices such as a tablet (Tablet Personal Computer, Tablet), a notebook computer (Notebook, NB), a monitor (Monitor, MNT) and a television (Television, TV).

[0190] Fig.16 : is a spectrum diagram of the blue light and purple light bands provided by the embodiment of the present disclosure under different currents. Fig.16 The horizontal axis is wavelength in nanometers, and the vertical axis is spectral apparent efficiency. The lines from bottom to top correspond to 5mA, 10mA, 15mA, 20mA, 25mA, 30mA, 35mA, 40mA, 45mA, 50mA, 55mA and 60mA currents. From left to right, the first peak is the violet band, and the second peak is the blue band. It can be clearly seen that the spectral apparent efficiency of the violet band is greatly affected by the current.

[0191] It should be noted that Fig.16 Only the influence of different currents on the spectral energy of blue light and purple light is shown. Usually, the current used to control the light-emitting unit is several hundred milliamperes, at which time the spectral energy of purple light is higher than that of blue light.

[0192] The above description is only an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A light emitting device, characterized in that: The light-emitting device comprises: a circuit board (101), a plurality of first light-emitting units (102) and a plurality of second light-emitting units (103), wherein the plurality of first light-emitting units (102) and the plurality of second light-emitting units (103) are both located on the circuit board (101); The first light-emitting unit (102) comprises at least one purple light-emitting diode chip (2031); The second light-emitting unit (103) comprises at least two light-emitting diode chips (203) and a fluorescent layer (205) covering the at least two light-emitting diode chips (203), the at least two light-emitting diode chips (203) comprising a blue light-emitting diode chip (2032) and a purple light-emitting diode chip (2031), and the second light-emitting unit (103) emits white light.

2. The light emitting device according to claim 1, characterized in that: The peak light emission wavelength of the purple light emitting diode chip (2031) of the first light emitting unit (102) is in the range of 400 to 410 nm.

3. The light emitting device according to claim 2, characterized in that: The peak ranges of the emission wavelengths of the purple light emitting diode chip (2031) and the blue light emitting diode chip (2032) of the second light emitting unit (103) are 400-410 nm and 457.5-465 nm respectively.

4. The light emitting device according to claim 1, characterized in that: The plurality of first light-emitting units (102) and the plurality of second light-emitting units (103) are arranged in a row on the circuit board (101), and the first light-emitting units (102) and the second light-emitting units (103) are arranged alternately.

5. The light emitting device according to claim 4, characterized in that: The first light-emitting unit (102) comprises two purple light-emitting diode chips (2031), and the two purple light-emitting diode chips (2031) are connected in series.

6. The light emitting device according to claim 4, characterized in that: The second light-emitting unit (103) comprises a blue light-emitting diode chip (2032) and a purple light-emitting diode chip (2031), and the blue light-emitting diode chip (2032) and the purple light-emitting diode chip (2031) are connected in series.

7. The light emitting device according to any one of claims 1 to 6, characterized in that: The light emitting spectrum of the light emitting device has a first wavelength peak and a second wavelength peak, the first wavelength peak wavelength range is 390 to 420 nm, the second wavelength peak wavelength range is 435 to 475 nm, and the ratio of the relative value of the first wavelength peak to the relative value of the second wavelength peak is 4:1 to 6:

1.

8. The light emitting device according to claim 7, characterized in that: The fluorescent layer (205) is a mixture of fluorescent powder and glue, the fluorescent powder includes yellow fluorescent powder and red fluorescent powder, the yellow fluorescent powder is yellow powder with an emission wavelength of 545-555 nm, and the red fluorescent powder is red powder with an emission wavelength of 620-640 nm.

9. A backlight module, characterized in that: The backlight module comprises a light-emitting device and a current controller (104), wherein the light-emitting device is the light-emitting device according to any one of claims 1 to 8, and the current controller (104) is used to control the current of at least one first light-emitting unit (102) according to the current of at least one second light-emitting unit (103), or to control the current of at least one second light-emitting unit (103) according to the current of at least one first light-emitting unit (102).

10. A display panel, characterized in that: The display panel comprises: a backlight module (10) and a liquid crystal panel (20); the liquid crystal panel (20) is located on the light emitting surface of the backlight module (10); The backlight module (10) is the backlight module according to claim 9.

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