Photoelectric coupling device

Abstract

The invention discloses a photoelectric coupling device which comprises a substrate, a plastic packaging layer, a light-emitting chip arranged on the substrate and a light-sensing chip correspondingly overlapped on the light-emitting surface of the light-emitting chip. And the light-emitting chip and the light-sensitive chip are completely accommodated in the plastic packaging layer. The light-emitting chip and the light-sensing chip which are arranged opposite to the solid crystal are arranged on the substrate and are packaged by the plastic packaging layer, so that the arrangement distance between the light-emitting chip and the light-sensing chip can be reduced, the arrangement space of the light-emitting chip and the light-sensing chip is optimized, the light transmission distance of the light-emitting chip and the light transmission distance of the light-sensing chip are shortened, and the light transmission efficiency is improved. Therefore, the structural packaging stability and the working reliability of the photoelectric coupling device are improved, a multi-layer colloid plastic packaging structure is reduced, the packaging cost is reduced, and low-cost and high-reliability photoelectric coupling device packaging is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric coupling devices, and particularly relates to a photoelectric coupling device. BACKGROUND

[0002] The photoelectric coupling device is packaged and coated in the same package by packaging the light-emitting chip and the photosensitive chip, and the internal structure of the package is arranged as a contrast type or a reflective photosensitive arrangement structure. The light-emitting chip and the photosensitive chip need to be arranged with corresponding metal frame structures, and the electrical connection structure is formed by connecting the welding wires. Finally, the insulation distance requirement is met by the multi-layer insulation glue plastic packaging method. Since the existing photoelectric coupling device needs to be filled with insulation glue at the input end and the output end, the device needs to be twice plasticized and twice glued, and double-layer supports and double-layer glue are used, which leads to complex device packaging process, size limitation, and high cost. SUMMARY

[0003] The present application provides a photoelectric coupling device, which shortens the light transmission distance of the light-emitting chip and the photosensitive chip by arranging the light-emitting chip and the photosensitive chip opposite to the die bonding arrangement on the substrate. The single-layer glue packaging of the plastic sealing layer can meet the plastic packaging requirements of the photoelectric coupling device, reduce the packaging cost, and realize the low-cost and high-reliability packaging of the photoelectric coupling device.

[0004] The present application provides a photoelectric coupling device, which shortens the light transmission distance of the light-emitting chip and the photosensitive chip by arranging the light-emitting chip and the photosensitive chip opposite to the die bonding arrangement on the substrate. The single-layer glue packaging of the plastic sealing layer can meet the plastic packaging requirements of the photoelectric coupling device, reduce the packaging cost, and realize the low-cost and high-reliability packaging of the photoelectric coupling device. The light-emitting chip and the photosensitive chip are completely contained in the plastic sealing layer.

[0005] Further, the photosensitive surface of the photosensitive chip is arranged opposite to the light-emitting surface of the light-emitting chip, forming a butt joint type photoelectric coupling device structure.

[0006] Further, the photosensitive surface of the photosensitive chip is arranged opposite to the light-emitting surface of the light-emitting chip, forming a butt joint type photoelectric coupling device structure.

[0007] Further, the photoelectric coupling device further comprises a light-transmitting layer. The light-emitting surface of the light-emitting chip and the photosensitive chip are completely contained in the light-transmitting layer.

[0008] Further, the photoelectric coupling device further comprises a reflective layer, and the reflective layer is arranged between the light-transmitting layer and the plastic sealing layer. The refractive index of the reflective layer is alpha, and the value range of alpha is 1.43<=alpha<=1.63.

[0009] Furthermore, the light-emitting chip is one of the following: upright chip structure, flip chip structure, and vertical chip structure.

[0010] The photosensitive chip is one of the following: upright chip structure, flip chip structure, and vertical chip structure.

[0011] Furthermore, the wavelength of the light emitted by the light-emitting chip is Ω, and the value range of Ω is: 300nm≤Ω≤1100nm.

[0012] Furthermore, the substrate is one of BT board, EMC board, SMC board, FR4 board, PPA board, PCT board, ceramic insulating substrate, or Cu alloy or Fe alloy metal frame.

[0013] Furthermore, the thickness of the substrate is h1, and the value of h1 ranges from 0.15mm to h1 to 2mm.

[0014] Furthermore, the substrate thickness of the light-emitting chip is h2, and the value range of h2 is: 30μm≤h2≤500μm.

[0015] Furthermore, an insulating block is provided between the light-emitting chip and the photosensitive chip; When the optocoupler is a docking optocoupler structure, the insulating block is made of a light-transmitting material.

[0016] Furthermore, the substrate is provided with a plurality of base islands, and the base islands are made of metal. The chip electrodes of the photosensitive chip are electrically connected to the base island via bonding wires.

[0017] Furthermore, the chip electrodes of the light-emitting chip are electrically connected to the base island via bonding wires, and / or the chip electrodes of the light-emitting chip are directly die-bonded to the base island.

[0018] Furthermore, when the photosensitive chip is a vertical chip, a connecting electrode is provided at the top of the photosensitive chip, and the connecting electrode is electrically connected to the bottom electrode of the photosensitive chip.

[0019] Furthermore, the ratio of the projected area of ​​the light-emitting chip to the projected area of ​​the photosensitive chip is a, and the value of a ranges from 1 to a ≤ 2.

[0020] This invention provides an optocoupler that, by placing a light-emitting chip and a photosensitive chip facing each other on a substrate and encapsulating them with a molding compound, reduces the spacing between the light-emitting and photosensitive chips, optimizes their arrangement space, and shortens the light transmission distance between them. This improves the structural packaging stability and operational reliability of the optocoupler, reduces the need for multi-layer encapsulation, lowers packaging costs, and achieves low-cost, high-reliability optocoupler packaging. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the optocoupler structure of the docking type optocoupler in this embodiment of the invention; Figure 2 This is a top view of the optocoupler structure in an embodiment of the present invention; Figure 3 This is a top view of the optocoupler device with a positively mounted chip structure in an embodiment of the present invention; Figure 4 This is an appendix to the embodiments of the present invention. Figure 3 Enlarged schematic diagram of the structure at point A; Figure 5 This is a top view of the optocoupler device with a vertical chip structure for light-emitting chips in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the optocoupler device with a parallel optical coupling device structure in an embodiment of the present invention; Figure 7 This is a schematic diagram of another structural state of the optocoupler device with a parallel optocoupler structure in an embodiment of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: Figure 1This invention illustrates a schematic diagram of the optocoupler structure of a docking type optocoupler in an embodiment of the present invention. Figure 2 A top view of the structure of an optocoupler in an embodiment of the present invention is shown. The optocoupler includes: a substrate 1, a molding compound 5, a light-emitting chip 2 disposed on the substrate 1, and a photosensitive chip 3 correspondingly stacked on the light-emitting surface of the light-emitting chip 2. The light-emitting chip 2 and the photosensitive chip 3 are completely contained within the molding compound 5. By stacking the light-emitting chip 2 and the photosensitive chip 3, the packaging operation of the optocoupler can be simplified and the packaging size of the optocoupler can be reduced.

[0025] Specifically, in this embodiment, the photosensitive surface of the photosensitive chip 3 and the light-emitting surface of the light-emitting chip 2 are arranged facing each other, forming a mating optical coupler structure. This allows the photosensitive surface of the photosensitive chip 3 to be directly bonded to the light-emitting surface of the light-emitting chip 2 using transparent adhesive, and the light emitted from the light-emitting chip 2 can be directly transmitted to the photosensitive surface of the photosensitive chip 3 through the transparent adhesive, thereby improving the light transmission and sensing effect between the light-emitting chip 2 and the photosensitive chip 3.

[0026] Furthermore, when the photosensitive chip 3 is a front-mounted chip structure, and the dual electrode pads of the photosensitive chip 3 are on the same side as the photosensitive surface, the photosensitive surface of the photosensitive chip 3 faces upward, that is, the optocoupler is a parallel packaging structure. When the photosensitive chip 3 is a flip-chip structure, and the dual electrode pads of the photosensitive chip 3 and the photosensitive surface are located on different sides of the chip, the photosensitive surface of the photosensitive chip 3 faces downward, that is, the optocoupler is a mating package structure.

[0027] Specifically, in this embodiment, the optocoupler is a mating optocoupler structure. The optocoupler also includes a molding compound 5, in which the light-emitting chip 2 and the photosensitive chip 3 are completely contained. The molding compound 5 uses an opaque molding compound, preferably a black compound, so that the molding compound 5 can provide molding protection for the light-emitting chip 2 and the photosensitive chip 3. Since the light-emitting surface of the light-emitting chip 2 and the photosensitive surface of the photosensitive chip 3 are directly connected, the molding compound 5 provides molding protection for the light-emitting chip 2 and the photosensitive chip 3. By setting the molding compound 5 with black compound, on the one hand, it can absorb the light emitted from the light-emitting surface of the light-emitting chip 2, preventing light leakage from the optocoupler. On the other hand, the molding compound 5 can isolate the light from the external environment, preventing the external ambient light from interfering with the light transmission between the light-emitting chip 2 and the photosensitive chip 3 of the optocoupler, thereby improving the working reliability of the optocoupler.

[0028] Furthermore, the molding layer 5 can be made of epoxy resin, with carbon powder doped into it to form a black colloid, thus meeting the molding protection requirements for the light-emitting chip 2 and the photosensitive chip 3. By replacing the traditional two-stage encapsulation process with a single-layer molding process, and using a black colloid to protect the light-emitting chip 2 and the photosensitive chip 3, interference from external ambient light can be isolated from the optocoupler, ensuring its structural stability and operational reliability. Compared to traditional multi-layer encapsulation structures, the optocoupler proposed in this embodiment uses a single-layer epoxy resin molding protection. The molding layer 5 has a small coefficient of thermal expansion and small internal stress difference, effectively improving the reliability of the device encapsulation and giving the optocoupler good hermeticity.

[0029] Specifically, the substrate 1 can be made of BT board (Bismaleimide Triazine, resin-based copper clad), EMC (Epoxy Molding Compound), SMC board (Sheet Molding Compound), FR4 (Flame Retardant 4), PPA (Polyphthalamide), PCT (Poly1,4-cyclohexylene dimethylene terephthalate), ceramic insulating substrate, or Cu alloy or Fe alloy metal frame.

[0030] Furthermore, BT resin board is a high-performance thermosetting resin synthesized from bismaleimide and triazine resins, which is combined with glass fiber cloth to form a copper-clad laminate, serving as a conventional chip device packaging substrate 1.

[0031] Furthermore, the thickness of the substrate 1 is h1, and the value of h1 is in the range of 0.15mm≤h1≤2mm, which has good support performance and can meet the die bonding and encapsulation requirements of the light-emitting chip 2 and the photosensitive chip 3.

[0032] Furthermore, the wavelength of the light emitted by the light-emitting chip 2 is Ω, and the value range of Ω is: 300nm≤Ω≤1100nm. The light-emitting chip 2 can be composed of binary chips such as gallium nitride (GaN) / gallium arsenide (GaAs) / gallium phosphide (GaP) / indium phosphide (InP), ternary chips such as aluminum gallium arsenide (AlGaAs) / indium gallium nitride (InGaN) / aluminum gallium nitride (AlGaN), and quaternary chip materials such as aluminum gallium indium phosphide (AlGaInP) to meet the light emission requirements of the light-emitting chip 2.

[0033] Specifically, an insulating block can be provided between the light-emitting chip 2 and the photosensitive chip 3 to increase the insulation distance between the light-emitting chip 2 and the photosensitive chip 3, so that the arrangement of the light-emitting chip 2 and the photosensitive chip 3 meets the safety standard insulation spacing requirements.

[0034] Furthermore, the insulating block is made of a light-transmitting material, allowing the light emitted by the light-emitting chip 2 to pass through the insulating block and be transmitted to the photosensitive surface of the photosensitive chip 3.

[0035] Specifically, Figure 3 A top view of the optocoupler device with a positively mounted chip structure is shown in an embodiment of the present invention. Figure 4 An embodiment of the present invention is shown. Figure 3 Enlarged schematic diagram of the structure at point A; Figure 5 This diagram shows a top view of an optocoupler device with a vertically oriented chip structure according to an embodiment of the present invention. The substrate 1 has several base islands, which are made of metal and can be a metal frame structure. The chip electrodes of the photosensitive chip 3 are electrically connected to the corresponding base islands via bonding wires 7. The substrate 1 is divided into at least four base islands, including a first base island 11, a second base island 12, a third base island 13, and a fourth base island 14. The photosensitive chip 3 has a first electrode 31 and a second electrode 32. The first electrode 31 of the photosensitive chip 3 is... The first bonding wire 71 is electrically connected to the first base island 11, and the second electrode 32 of the photosensitive chip 3 is electrically connected to the second base island 12 based on the second bonding wire 72. The photosensitive chip 3 is configured as a flip chip, and the photosensitive surface of the photosensitive chip 3 is bonded to the light-emitting surface of the light-emitting chip 2. The electrical electrodes of the photosensitive chip 3 are connected by bonding wires, so that the photosensitive chip 3 is electrically connected to the base island of the substrate 1, so that the electrical pins of the optocoupler extending from the base island of the substrate 1 are electrically connected to the external working circuit board.

[0036] Specifically, the chip electrodes of the light-emitting chip 2 are electrically connected to the base island based on the bonding wire 7, and / or the chip electrodes of the light-emitting chip 2 are directly die-bonded to the base island. An appropriate electrical connection method can be selected according to the chip structure of the light-emitting chip 2.

[0037] Furthermore, the light-emitting chip 2 can be one of a conventional chip structure, a flip-chip structure, or a vertical chip structure. The photosensitive chip 3 can be one of a conventional chip structure, a flip-chip structure, or a vertical chip structure. The light-emitting chip 2 is provided with a third electrode 21 and a fourth electrode 22. The third electrode 21 of the light-emitting chip 2 is electrically connected to the third base island 13, and the fourth electrode 22 of the light-emitting chip 2 is electrically connected to the fourth base island 14.

[0038] When the light-emitting chip 2 has a flip-chip structure, the third electrode 21 of the light-emitting chip 2 is directly die-bonded to the third base island 13 via soldering, and the fourth electrode 22 of the light-emitting chip 2 is directly die-bonded to the fourth base island 14 via soldering. By adopting a flip-chip structure, the light-emitting chip 2 can be directly die-bonded to the third base island 13 and the fourth base island 14, thereby reducing the wire bonding operations inside the optocoupler and improving the ease of installation of the light-emitting chip 2. By reducing the wire bonding structure, the wire bonding operations inside the optocoupler can be simplified, thereby improving the packaging efficiency of the optocoupler.

[0039] Furthermore, when the light-emitting chip 2 is a flip-chip structure, the light-emitting chip 2 of the flip-chip structure adopts a light-transmitting substrate structure, preferably a sapphire substrate. The sapphire substrate has good light transmittance, so that the light emitted by the light-emitting chip 2 can pass through the sapphire substrate to the photosensitive surface of the photosensitive chip 3, thereby ensuring the accuracy of light transmission between the light-emitting chip 2 and the photosensitive chip 3.

[0040] Furthermore, when preparing the light-emitting chip 2, semiconductor materials can be grown on a substrate with poor light transmittance (such as silicon, silicon carbide, gallium nitride, gallium arsenide, etc.) to provide a good growth environment for the semiconductor chip structure. After the structure of the light-emitting chip 2 is prepared, the original substrate is peeled off and the light-emitting chip 2 is directly transferred to a light-transmitting substrate (such as a sapphire substrate) to give the light-emitting chip 2 good light emission efficiency.

[0041] Furthermore, when the light-emitting chip 2 has a flip-chip structure, the chip electrode of the light-emitting chip 2 is located at the bottom of the chip structure, and the substrate of the light-emitting chip 2 is located at the top. The top surface of the substrate is set as the light-emitting surface of the light-emitting chip 2, so that the light emitted by the light-emitting chip 2 can be directly transmitted to the photosensitive surface of the photosensitive chip 3 through the substrate, thereby meeting the optocoupler requirements between the light-emitting chip 2 and the photosensitive chip 3. The thickness of the light-transmitting substrate is h2, and the value of h2 is in the range of 30μm≤h2≤500μm, so that the substrate of the light-emitting chip 2 has sufficient thickness to maintain the insulation distance between the light-emitting chip 2 and the photosensitive chip 3. This ensures that the insulation distance between the light-emitting chip 2 and the photosensitive chip 3 meets the safety insulation distance requirements of the optocoupler. By adjusting the insulation distance at the chip end, the die-bonding of the light-emitting chip 2 and the photosensitive chip 3 meets the insulation withstand voltage requirements, improving the convenience and reliability of the packaging and mating of the light-emitting chip 2 and the photosensitive chip 3.

[0042] Specifically, the photosensitive chip 3 can also be a vertical chip structure, with a connecting electrode added to the top surface of the photosensitive chip 3, and the connecting electrode having the same electrical properties as the bottom electrode of the photosensitive chip 3, so that the electrodes of the photosensitive chip 3 can be concentrated at the top surface of the photosensitive chip 3, so that the photosensitive chip 3 can be connected to the base island of the substrate 1 by wire bonding.

[0043] Specifically, the ratio of the projected area of ​​the light-emitting chip 2 to the projected area of ​​the photosensitive chip 3 is 'a', where 'a' ranges from 1 to 2. When the projected area of ​​the photosensitive chip 3 is smaller than that of the light-emitting chip 2, making the photosensitive surface of the photosensitive chip 3 smaller than the light-emitting surface of the light-emitting chip 2, when the photosensitive chip 3 and the light-emitting chip 2 are stacked and bonded, the photosensitive surface of the photosensitive chip 3 can be completely located within the light-emitting surface of the light-emitting chip 2, thereby ensuring the accuracy and stability of the photosensitive chip 3 in receiving the light emitted from the light-emitting chip 2.

[0044] Specifically, the optocoupler provided in this embodiment of the invention uses a stacked, face-to-face bonding of a light-emitting chip 2 and a photosensitive chip 3. Because the light-emitting chip 2 and the photosensitive chip 3 are die-bonded face-to-face, the mounting accuracy of the light-emitting chip 2 and the photosensitive chip 3 is controllable, effectively improving the die-bonding accuracy of the light-emitting chip 2 and the photosensitive chip 3. By arranging the light-emitting surface of the light-emitting chip 2 and the photosensitive surface of the photosensitive chip 3 face-to-face, the optocoupler can be encapsulated with an outer layer of epoxy resin. This single encapsulation protection can meet the encapsulation requirements of the optocoupler, simplifying the packaging process and reducing manufacturing costs.

[0045] Example 2: Figure 6 The diagram shows a schematic of the structure of a photoelectric coupling device with a parallel optical coupling device structure in an embodiment of the present invention. The device includes a substrate 1, a light-emitting chip 2 disposed on the substrate 1, and a photosensitive chip 3 correspondingly stacked on the light-emitting surface of the light-emitting chip 2. The structures of the substrate 1, the light-emitting chip 2, and the photosensitive chip 3 are the same as those in the first embodiment described above, and will not be described in detail here.

[0046] In this embodiment, the optocoupler is a parallel optocoupler structure. The photosensitive chip 3 and the light-emitting chip 2 are stacked together, with the photosensitive surface of the photosensitive chip 3 facing upwards and the light-emitting surface of the light-emitting chip 2 facing upwards, so that the photosensitive surface of the photosensitive chip 3 and the light-emitting surface of the light-emitting chip 2 can form two parallel surfaces. The optocoupler also includes a light-transmitting layer 4 and a molding layer 5. The light-emitting surface of the light-emitting chip 2 and the photosensitive chip 3 are completely contained within the light-transmitting layer 4. The light-transmitting layer 4 constructs a light transmission carrier between the light-emitting surface of the light-emitting chip 2 and the photosensitive surface of the photosensitive chip 3, which can ensure the stability and accuracy of light transmission between the light-emitting chip 2 and the photosensitive chip 3.

[0047] The molding layer 5 covers the outside of the light-transmitting layer 4. The molding layer 5 is made of opaque molding compound, preferably black colloid, so that the molding layer 5 can provide molding protection for the light-emitting chip 2 and the photosensitive chip 3. The molding layer 5 can absorb the light emitted by the light-emitting chip 2 through the light-transmitting layer 4, and at the same time absorb the light from the external environment, thereby preventing the light from the light-transmitting layer 4 from leaking outward and preventing the external ambient light from affecting the operation of the optocoupler device.

[0048] Furthermore, the molding layer 5 can be made of epoxy resin, with carbon powder doped into it, so that the epoxy resin can form a black colloid. This can meet the molding protection requirements for the light-emitting chip 2 and the photosensitive chip 3. By molding and protecting the light-emitting chip 2 and the photosensitive chip 3 with the black colloid, interference from external ambient light to the optocoupler can be isolated, ensuring the structural stability and operational reliability of the optocoupler.

[0049] Furthermore, the light-transmitting layer 4 is made of materials such as silicone, silicone resin, or epoxy resin. If high-purity silicone is used, the light-transmitting layer 4 covering the light-emitting chip 2 and the photosensitive chip 3 is formed through dispensing, molding, or injection molding processes. The light transmittance of epoxy resin can be controlled between 80% and 99%. For example, modified epoxy resin can be used, and the light-transmitting layer 4 is formed through a curing process, which can meet the light transmittance requirements of the light-emitting chip 2. The high mechanical strength of epoxy resin can enhance the impact resistance of the encapsulation structure, and its interfacial bonding with the molding layer 5 can improve the overall sealing performance.

[0050] Furthermore, the transmittance of the light-transmitting layer 4 is β, and the value of β is in the range of 80%≤β≤99%. The insulating and light-transmitting material of the light-transmitting layer 4 can be silicone with a transmittance of 90-99%; the insulating and light-transmitting material of the light-transmitting layer 4 can also be epoxy resin with a transmittance of 80-90%. Silicone and epoxy resin have excellent light transmission performance, which can meet the light transmission requirements between the light-emitting chip 2 and the photosensitive chip 3, and reduce the light loss of the light-transmitting layer 4 between the light-emitting chip 2 and the photosensitive chip 3, thereby ensuring the photosensitive operation between the light-emitting chip 2 and the photosensitive chip 3.

[0051] Specifically, Figure 7 This diagram illustrates another structural state of the optocoupler device with a parallel optocoupler structure according to an embodiment of the present invention. The optocoupler device is further provided with a reflective layer 6, which is disposed between the light-transmitting layer 4 and the encapsulation layer 5. The reflective layer 6 completely covers the surface of the light-transmitting layer 4. The reflective layer 6 can reflect the light emitted outward from the light-transmitting layer 4, so that the light inside the light-transmitting layer 4 can be retained in the light-transmitting layer 4 after being reflected by the reflective layer 6. This can reduce the absorption of the light emitted by the light-transmitting layer 4 by the encapsulation layer 5, that is, reduce the light loss of the light-emitting chip 2, thereby improving the photosensitivity of the optocoupler device.

[0052] Furthermore, the reflective layer 6 is an organic composite resin layer, and the reflective effect of the organic composite resin layer is suitable for light wavelengths of γ, wherein the value of γ is 300nm≤γ≤1100nm. The reflective layer 6 is prepared by a spraying process, with at least three alternating layers. The bottom layer of the multilayer structure is a layer with a higher refractive index, so that the reflective wavelength of the reflective layer 6 covers the range of 300-1100nm. The wavelength of the light emitted by the light-emitting chip 2 is Ω, wherein the value of Ω is 300nm≤Ω≤1100nm. The reflective layer 6 can meet the wavelength range of the light emitted by the light-emitting chip 2, and can effectively reflect the light emitted by the light-emitting chip 2, reducing light loss.

[0053] Specifically, the refractive index of the reflective layer 6 is α, and the value of α ranges from 1.43 to 1.63. The reflective layer 6 is composed of alternating layers with higher and lower refractive indices. The higher refractive index layers have a refractive index range between 1.53 and 1.63 and are formed by mixing titanium dioxide (TiO2) powder, phenyl silicone resin, and isomeric alkane organic solvent in a ratio of 0.02-0.2:1:1-3. The lower refractive index layers have a refractive index range between 1.42 and 1.53 and are formed by mixing titanium dioxide (TiO2) powder, phenyl silicone resin, and isomeric alkane organic solvent in a ratio of 0.02-0.2:1:1-3. Titanium oxide (TiO2) powder, methyl silica gel, and isoparaffin organic solvent are mixed in a ratio of 0.02-0.2:1:1-3 to form a reflective layer 6. The reflective layer 6 is used to reflect the light in the light-transmitting layer 4, so that the light in the light-transmitting layer 4 can be reflected onto the photosensitive surface of the photosensitive chip 3, thereby avoiding the absorption of the light in the light-transmitting layer 4 by the encapsulation layer 5, reducing the loss of light in the light-transmitting layer 4, and thus improving the photocoupler photosensitivity and photoelectric conversion efficiency between the light-emitting chip 2 and the photosensitive chip 3.

[0054] Specifically, the light-emitting chip 2 can be one of a conventional chip structure, a flip-chip structure, or a vertical chip structure. The photosensitive chip 3 can be one of a conventional chip structure, a flip-chip structure, or a vertical chip structure.

[0055] The substrate 1 is provided with a plurality of base islands, and the base islands are made of metal. The photosensitive chip 3 is connected to the corresponding base islands on the substrate 1 by wire bonding to realize the electrical connection of the photosensitive chip 3. When the photosensitive chip 3 is a vertical chip, a connection electrode is provided on the top of the photosensitive chip 3. The connection electrode is electrically connected to the bottom electrode of the photosensitive chip 3, so that the connection electrode on the top of the photosensitive chip 3 and the bottom electrode are electrically identical. By concentrating the electrodes of the photosensitive chip 3 at the top position, the top wire bonding connection of the photosensitive chip 3 can be performed.

[0056] Specifically, the optocoupler provided in this embodiment of the invention uses a stacked and bonded light-emitting chip 2 and a photosensitive chip 3. Since the light-emitting chip 2 and the photosensitive chip 3 are die-bonded facing each other, the mounting accuracy of the light-emitting chip 2 and the photosensitive chip 3 is controllable, effectively improving the die-bonding accuracy of the light-emitting chip 2 and the photosensitive chip 3. By arranging the light-emitting surface of the light-emitting chip 2 and the photosensitive surface of the photosensitive chip 3 in parallel, the light-emitting chip 2 and the photosensitive chip 3 can be fixed by welding or adhesive, improving the connection stability between the light-emitting chip 2 and the photosensitive chip 3, simplifying the packaging process of the optocoupler, and reducing manufacturing costs.

[0057] Furthermore, the optocoupler provided in the embodiments of the present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An optocoupler, characterized in that, The optocoupler includes: a substrate, a molding layer, a light-emitting chip disposed on the substrate, and a photosensitive chip correspondingly stacked on the light-emitting surface of the light-emitting chip; The light-emitting chip and the photosensitive chip are completely encapsulated within the molding layer.

2. The optocoupler as described in claim 1, characterized in that, The photosensitive surface of the photosensitive chip and the light-emitting surface of the light-emitting chip are arranged facing each other to form a docking optical coupler structure.

3. The optocoupler as described in claim 1, characterized in that, The photosensitive surface of the photosensitive chip and the light-emitting surface of the light-emitting chip face the same direction, forming a parallel optical coupler structure.

4. The optocoupler as described in claim 3, characterized in that, The optocoupler further includes a light-transmitting layer; The light-emitting surface of the light-emitting chip and the photosensitive chip are completely housed within the light-transmitting layer.

5. The optocoupler as described in claim 3, characterized in that, The optocoupler further includes a reflective layer, which is disposed between the light-transmitting layer and the encapsulation layer; The refractive index of the reflective layer is α, and the value of α is in the range of 1.43≤α≤1.

63.

6. The optocoupler as described in claim 1, characterized in that, The light-emitting chip is one of the following: upright chip structure, flip chip structure, and vertical chip structure; The photosensitive chip is one of the following: upright chip structure, flip chip structure, and vertical chip structure.

7. The optocoupler as described in claim 1, characterized in that, The wavelength of the light emitted by the light-emitting chip is Ω, and the value range of Ω is: 300nm≤Ω≤1100nm.

8. The optocoupler as described in claim 1, characterized in that, The substrate is one of the following: BT board, EMC board, SMC board, FR4 board, PPA board, PCT board, ceramic insulating substrate, or Cu alloy or Fe alloy metal frame.

9. The optocoupler as described in claim 1, characterized in that, The thickness of the substrate is h1, and the value of h1 is in the range of 0.15mm≤h1≤2mm.

10. The optocoupler as described in claim 1, characterized in that, The substrate thickness of the light-emitting chip is h2, and the value of h2 is in the range of 30μm≤h2≤500μm.

11. The optocoupler as described in claim 2 or 3, characterized in that, An insulating block is provided between the light-emitting chip and the photosensitive chip; When the optocoupler is a docking optocoupler structure, the insulating block is made of a light-transmitting material.

12. The optocoupler as described in claim 1, characterized in that, The substrate is provided with a plurality of base islands, and the base islands are made of metal. The chip electrodes of the photosensitive chip are electrically connected to the base island via bonding wires.

13. The optocoupler as described in claim 12, characterized in that, The chip electrodes of the light-emitting chip are electrically connected to the base island via bonding wires, and / or the chip electrodes of the light-emitting chip are directly die-bonded to the base island.

14. The optocoupler as described in claim 12, characterized in that, When the photosensitive chip is a vertical chip, a connecting electrode is provided on the top of the photosensitive chip, and the connecting electrode is electrically connected to the bottom electrode of the photosensitive chip.

15. The optocoupler as described in claim 1, characterized in that, The ratio of the projected area of ​​the light-emitting chip to the projected area of ​​the photosensitive chip is a, and the value of a ranges from 1 to a ≤ 2.

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