A method of manufacturing an optoelectronic coupler

Abstract

The application discloses a manufacturing method of an optoelectronic coupler. The manufacturing method comprises: independently packaging an infrared light-emitting chip and a photosensitive receiving chip respectively to form infrared light-emitting devices and photosensitive receiving devices with independent pads; welding the infrared light-emitting devices and the photosensitive receiving devices to the same plane substrate in a surface mounting manner; physically bending the plane substrate to convert the infrared light-emitting devices and the photosensitive receiving devices from a plane layout to a three-dimensional layout, and to make a light-emitting surface and a light-receiving surface optically aligned with each other; filling a transparent light-conducting adhesive between the light-emitting surface of the infrared light-emitting device and the light-receiving surface of the photosensitive receiving device; and coating a light-shielding packaging adhesive outside the three-dimensional structure, and only exposing pins for external connection. Through the above method, the manufacturing method of the optoelectronic coupler has a simple process flow, greatly reduces the manufacturing cost, significantly improves the overall yield, and greatly saves the material cost.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a method for manufacturing an optocoupler. Background Technology

[0002] An optocoupler is an electro-optical-electrical conversion device that transmits electrical signals using light as a medium. It is widely used in electrical isolation, signal transmission, and logic circuits, and is an indispensable key component in power electronics, communications, and industrial control. However, as electronic devices develop towards miniaturization, thinner designs, and higher integration, extremely high challenges are posed to the packaging size, manufacturing cost, and production yield of optocouplers.

[0003] Existing technologies for achieving three-dimensional optical path coupling in optocouplers mainly face the following bottlenecks: On the one hand, in pursuit of miniaturization and high performance, bare chips are often directly stacked within a single package (such as over / under structures). This not only places extremely high precision requirements on the packaging equipment, but also makes the bare chips highly susceptible to damage during three-dimensional assembly, leading to a decrease in yield. Furthermore, the use of dual-support or multi-layer substrates significantly increases material costs. On the other hand, while light guide solutions used to simplify assembly avoid bare chip stacking, the light guides themselves are high-value consumables, resulting in high overall costs and hindering widespread adoption in general-purpose applications. In addition, traditional packaging processes are limited by the vertical operation mode of the equipment, making it difficult to utilize mature planar mounting technologies and restricting further improvements in production efficiency.

[0004] Therefore, existing technologies lack a manufacturing solution that can efficiently construct highly reliable three-dimensional optical paths using low-cost planar processes. Summary of the Invention

[0005] This application provides a method for manufacturing an optocoupler to solve the problems of high manufacturing cost, complex process, limited miniaturization, and low yield of current optocouplers.

[0006] To solve the above-mentioned technical problems, this application adopts a technical solution as follows: a method for manufacturing an optocoupler. The method includes: Step S1: independently packaging an infrared light-emitting chip and a photosensitive receiving chip to form an infrared light-emitting device and a photosensitive receiving device with independent pads; Step S2: soldering the infrared light-emitting device and the photosensitive receiving device onto the same planar substrate in a planar mounting manner, wherein the light-emitting surface and the light-receiving surface of both devices face the same side of the planar substrate; Step S3: physically bending the planar substrate to transform the planar layout of the infrared light-emitting device and the photosensitive receiving device from a planar layout to a three-dimensional layout, and optically aligning the light-emitting surface and the light-receiving surface with each other; Step S4: filling the space between the light-emitting surface of the infrared light-emitting device and the light-receiving surface of the photosensitive receiving device with a transparent light-guiding colloid; Step S5: covering the three-dimensional structure formed in Step S3 with a light-shielding encapsulating colloid, exposing only the pins for external connection.

[0007] In some embodiments, in step S2, the step of soldering the infrared light-emitting device and the photosensitive receiving device onto the same planar substrate in a planar mounting manner includes: Using a reflow soldering process, the bottom pads of the infrared light-emitting device and the photosensitive receiving device are respectively soldered to the corresponding pre-set pads on the planar substrate using solder paste.

[0008] In some embodiments, the planar substrate is a metal lead frame, and the metal lead frame is thinned in a predetermined bending area by a semi-etching process to form a hinge structure with extensibility.

[0009] In some embodiments, in step S3, a fixture is used to apply mechanical force to the metal lead frame along the hinge structure, and the area where the infrared light-emitting device and the photosensitive receiving device are mounted is rotated by a specific angle along the bending line.

[0010] In some embodiments, in step S3, the specific angle is 90 degrees, and the bending angle is controlled within 90 degrees ± 1 degree by monitoring real-time force feedback, so that the light emitting surface and the light receiving surface form a face-to-face direct beam arrangement.

[0011] In some embodiments, the planar substrate is provided with a reflective surface; In step S3, the planar substrate is physically bent so that the infrared light-emitting device and the photosensitive receiving device are tilted at a specific angle, so that the light emitted by the infrared light-emitting device shines on the reflective surface and is reflected by the reflective surface to the light-receiving surface of the photosensitive receiving device.

[0012] In some embodiments, the reflective surface is a high-reflectivity coating formed on the planar substrate in step S1 or step S2, or a miniature reflector mounted on the planar substrate.

[0013] In some embodiments, in step S4, the refractive index of the transparent light guide colloid is between 1.4 and 1.6 to match the refractive index of the window material of the infrared light-emitting device and the photosensitive receiving device, thereby reducing Fresnel reflection loss.

[0014] In some embodiments, in step S4, the transparent light guide colloid is injected through a dispensing process. The transparent light guide colloid fills the gaps in the optical path under capillary action and is cured by heating or ultraviolet irradiation to form a solid light transmission medium.

[0015] In some embodiments, in step S5, the light-shielding encapsulating colloid is an epoxy resin filled with carbon black, which is applied to the periphery of the three-dimensional structure by molding or coating processes, covering all light-transmitting areas except for the pins.

[0016] The beneficial effects of this application are as follows: Unlike existing technologies, this application discloses a method for manufacturing a discretely packaged optocoupler. In this application, the infrared light-emitting device and the photosensitive receiving device are pre-packaged discretely, then soldered onto the same substrate using planar mounting technology, and finally aligned in three dimensions through physical bending. First, by using discrete device packaging and standard SMT mounting, mature industry chain resources are utilized, significantly reducing manufacturing costs. Furthermore, discrete devices can be screened before mounting, significantly improving overall yield. Second, physical bending transforms the planar layout into a three-dimensional layout, eliminating the need for traditional complex dual-support stacking molds or expensive light guide sheets; a miniaturized structure can be achieved with only a single substrate, greatly saving material costs. Finally, the combination of optical colloid filling and light-shielding sealing ensures the optoelectronic performance and reliability of the device. This method has a simple process flow, is suitable for large-scale automated production, and effectively solves the problems of low yield and complex processes caused by the use of bare chip three-dimensional stacking, as well as high costs and limited miniaturization caused by the use of expensive structures in existing technologies. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a schematic flowchart of an embodiment of the manufacturing method of the optocoupler provided in this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] The terms "first," "second," and "third" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] To address the problems of high packaging cost, complex processes, limited miniaturization, and low yield in existing optocoupler technologies, this application provides an optocoupler manufacturing solution based on discrete packaging and physical bending. This solution involves packaging discrete components into standard LED chips, then mounting them planar using SMT (Surface Mount Technology). Subsequently, a physical bending process transforms the planar arrangement into a three-dimensional through-beam layout. Finally, refractive index-matched colloid filling and light-shielding sealing are used to form a high-performance, miniaturized optocoupler. This process requires only conventional LED packaging lines, SMT equipment, and bending equipment, eliminating the need for expensive dual-support stacking molds or light guides, significantly reducing equipment investment and operating costs.

[0022] Example 1 Specifically, this application provides a method for manufacturing an optocoupler, see reference. Figure 1 , Figure 1This is a schematic flowchart of an embodiment of the manufacturing method of the optocoupler provided in this application. The manufacturing method includes: Step S1: Separately package the infrared light-emitting chip and the photosensitive receiving chip to form an infrared light-emitting device and a photosensitive receiving device with independent pads.

[0023] The infrared light-emitting device employs standard LED packaging technology. Specifically, an infrared LED chip is selected and bonded to an LED bracket cup with two independent pads using die-attach adhesive. The anode and cathode on the chip surface are connected to the corresponding bracket pads via gold wire bonding. Then, an encapsulating epoxy resin is injected and thermo-cured to form an independent infrared light-emitting bead. Its light-emitting surface is located at the top or side of the device. It is mass-produced using a standard LED production line, resulting in extremely low cost.

[0024] For the photosensitive receiving device, this embodiment adopts a core three-electrode vertical structure. The three-electrode vertical structure includes: a first electrode located at the bottom of the chip, which is connected to the main pad at the bottom of the device via conductive silver paste; a second electrode located at the top of the chip, which is connected to another independent pad at the bottom of the device via bonding wires; and a light-receiving surface located at the top of the chip, which serves as a functional third electrode and is aligned with the light-transmitting window at the top of the device.

[0025] Traditional photosensitive chips typically have a two-electrode structure, making direct electrical connection via the bottom pad difficult and often requiring complex side metallization processes or special lead frames. This embodiment employs a three-electrode vertical structure design, with the bottom electrode designed as either a collector or cathode. Conductive silver paste directly connects the bottom electrode to the device's bottom pad, achieving a large-area electrical and physical connection. This not only reduces thermal resistance and electrical resistance, but more importantly, this bottom-conductive characteristic allows the photosensitive receiver to be directly mounted using standard SMT reflow soldering processes in the subsequent planar mounting step S2, without the need for additional side metallization or complex lead frame bending. The top surface emitter is led out using conventional gold wire ball bonding, while the light-receiving surface naturally aligns with the light-transmitting window on the top of the device. This design cleverly transforms a three-dimensional electrode lead-out problem into a two-dimensional problem that can be perfectly solved in planar packaging, enabling the photosensitive receiver to be manufactured and mounted efficiently and cost-effectively, just like a standard LED chip. Furthermore, the bottom first electrode and the top second electrode are physically and electrically isolated through a PN junction, ensuring the device's electrical performance.

[0026] Step S2: The infrared light-emitting device and the photosensitive receiving device are soldered onto the same planar substrate in a planar mounting manner, at which time the light emitting surface and the light receiving surface of both face the same side of the planar substrate.

[0027] Specifically, the planar substrate can be made of a metal lead frame, such as an iron-nickel alloy or a copper alloy. The planar substrate has pads for mounting devices and input / output pins for final connection to external circuitry.

[0028] The metal lead frame is typically made of high-precision copper alloy or iron-nickel alloy strip with a thickness of 0.1mm to 0.3mm. Before mounting, the metal lead frame undergoes a precision etching or stamping process to form a specific pattern. In particular, to enable subsequent physical bending, the metal lead frame has its material thickness reduced in the pre-defined bending area using a semi-etching process, forming a flexible hinge structure.

[0029] The specific process of the semi-etching process is as follows: A photosensitive dry film is applied to the surface of the metal lead frame. The pattern of the bending area is revealed through exposure and development. Then, a chemical etching solution is used to etch this area on one side. By controlling the etching time, the thickness of the bending area is reduced to 30%-50% of its original thickness, for example, from 0.2 mm to 0.08 mm. This thinned area not only maintains the ductility of the metal but also becomes a natural guide line for stress concentration, ensuring that cracks or deformations during bending occur only at this location and do not affect the area where the mounted device is located.

[0030] Using a reflow soldering process, the bottom pads of the infrared light-emitting device and the photosensitive receiver are soldered onto the corresponding pre-set pads on the planar substrate using solder paste.

[0031] The mature SMT reflow soldering process is used for planar mounting, leveraging the patterning precision of the pads to ensure the relative positional accuracy of the two devices on the plane. Compared to traditional methods that manually align chips in three-dimensional space using high-precision fixtures, the SMT process offers higher precision and consistency and is suitable for large-scale automated production. At this point, the light emitted by the infrared emitting device is perpendicular to the planar substrate and pointing upwards, while the light-receiving surface of the photosensitive receiving device also faces upwards towards the planar substrate. Both are on the same horizontal plane and have not yet formed an effective optical path.

[0032] Step S3: Physically bend the planar substrate to transform the infrared light-emitting device and the photosensitive receiver from a planar layout to a three-dimensional layout, and optically align the light-emitting surface and the light-receiving surface with each other.

[0033] The planar substrate is a metal lead frame, and the material thickness is reduced in the predetermined bending area through a semi-etching process to form a hinge structure with ductility. A precision fixture is used to apply mechanical force to the metal lead frame along the hinge structure, and the area where the device is mounted is rotated by a specific angle along the bending line.

[0034] The hinge structure, formed using a semi-etching process, makes this area a stress concentration and release point, ensuring that the bending process occurs at a predetermined position and preventing unexpected substrate breakage. The precision fixture, in conjunction with the hinge structure, enables a controllable transition from planar to three-dimensional shape, guaranteeing the stability of the device during bending.

[0035] In some embodiments, the specific angle is 90 degrees, and the bending angle is controlled within 90 degrees ± 1 degree by monitoring real-time force feedback, so that the light emitting surface and the light receiving surface form a direct facing arrangement.

[0036] The face-to-face direct-beam arrangement formed by a 90-degree bend represents the most efficient path for light transmission. Extensive experimental verification has shown that excessive angular deviation leads to optical axis misalignment, significantly reducing photoelectric coupling efficiency (CTR). By monitoring force feedback and precisely controlling the angular tolerance (±1 degree), the optical axes of the infrared emitting device and the photosensitive receiving device are ensured to be highly aligned, thereby guaranteeing high consistency in photoelectric coupling efficiency during mass production. This step transforms the originally parallel, upward-facing devices into a precisely face-to-face, three-dimensional spatial arrangement.

[0037] As another optical path implementation, the planar substrate 30 is provided with a reflective surface 32. In step S3, the planar substrate is physically bent so that the infrared light-emitting device 10 and the photosensitive receiving device 20 are tilted at a specific angle, so that the light emitted by the infrared light-emitting device 10 illuminates the reflective surface 32 and is reflected by the reflective surface to the light-receiving surface of the photosensitive receiving device 20. The reflective surface 32 can be a high-reflectivity coating or a micro-mirror.

[0038] This solution offers a reflective coupling mode, increasing design flexibility. By adjusting the bending angle and the position of the reflective surface, optical coupling can be achieved without direct on-beam contact, making it suitable for applications requiring greater creepage distances or with specific height limitations. Furthermore, the reflective surface is fabricated during the planarization stage, without increasing process complexity. A high-reflectivity coating minimizes light loss, ensuring efficient signal transmission in the reflective coupling mode.

[0039] Step S4: Fill the space between the light emitting surface of the infrared light-emitting device and the light receiving surface of the photosensitive receiver with a transparent light guide colloid.

[0040] After step S3, although the infrared light-emitting device and the photosensitive receiver have formed a face-to-face three-dimensional arrangement in space, a physical gap still exists between them. If this gap is filled with air, it will lead to severe light loss. This is because when light enters the air (refractive index 1.0) from the encapsulating resin (refractive index approximately 1.5) of the light-emitting device, total internal reflection occurs, preventing a large amount of light from escaping; similarly, when light enters the encapsulating resin of the receiver from the air, interface reflection also occurs. This Fresnel reflection loss significantly reduces the current transfer ratio (CTR) of the optocoupler.

[0041] To address this issue, this embodiment employs a dispensing process to inject transparent light-guiding adhesive. Specifically, a high-precision dispensing machine is selected, and the needle is controlled to move above the gap between the infrared light-emitting device and the photosensitive receiving device, slowly and quantitatively injecting liquid transparent light-guiding adhesive.

[0042] Since the spacing between the devices after bending in step S3 is typically small, for example, 0.2mm to 0.5mm, and the surfaces of the two devices may have slight unevenness, direct filling can easily generate air bubbles. This embodiment utilizes the capillary action of liquids; the transparent light-guiding colloid is designed to have moderate viscosity and excellent wettability. When the colloid comes into contact with the edge of the device, it automatically penetrates deep along the bonding surfaces of the two devices. The capillary force not only drives the colloid to fill the narrow gap but also automatically removes air from the gap, forming a bubble-free light transmission channel.

[0043] In this embodiment, the refractive index of the transparent light guide colloid is between 1.4 and 1.6 to match the refractive index of the window material of the infrared light-emitting device and the photosensitive receiving device.

[0044] The external encapsulation of infrared light-emitting devices and photosensitive receiving devices is usually made of epoxy resin or silicone, with a refractive index generally between 1.50 and 1.53. If the refractive index of the filling colloid differs too much from the refractive index of the device encapsulation material, light will still be refracted and reflected during transmission. For example, in this embodiment, a transparent light guide colloid with a refractive index of 1.5 is selected.

[0045] When the refractive index of the filling colloid is exactly the same as that of the device encapsulation material, light travels as if in the same medium, virtually eliminating reflection loss at the interface. The light signal is emitted from the light-emitting chip, passes through the encapsulation resin and light-guiding colloid, and reaches the surface of the receiving chip directly, minimizing end-to-end optical loss. This "refractive index matching" design is one of the key technologies for improving the CTR value of optocouplers. Furthermore, the colloid must also possess good light transmittance, high-temperature resistance, and excellent insulation properties.

[0046] A transparent light-guiding colloid is injected through a dispensing process. The colloid fills the gaps in the light path under capillary action and is then cured by heating or ultraviolet irradiation to form a solid light transmission medium.

[0047] Light undergoes Fresnel reflection when propagating through interfaces between different media. This solution eliminates air gaps by filling the interface with a transparent light-guiding colloid whose refractive index matches the device window material, significantly reducing reflection loss and thus greatly improving the overall efficiency of optical signal transmission. The cured solid medium not only guides light but also serves to fix the three-dimensional structure and enhance mechanical strength.

[0048] Step S5: Cover the outside of the three-dimensional structure formed in step S3 with a light-shielding encapsulating colloid, exposing only the pins for external connection.

[0049] Although the transparent light guide colloid ensures unobstructed internal light path, external ambient light (such as sunlight, lamps, equipment indicator lights, etc.) will still enter the photosensitive receiving device if not blocked, resulting in false signals and damaging the isolation characteristics of the optocoupler.

[0050] In this embodiment, the light-shielding encapsulating colloid is an epoxy resin filled with carbon black, which is coated around the three-dimensional structure by molding or coating process, covering all light-transmitting areas except for the pins.

[0051] Carbon black epoxy resin has excellent light-shielding properties, which can completely isolate the interference of external ambient light, ensuring that the optocoupler only transmits internal optical signals, thus guaranteeing the device's high isolation and anti-interference capabilities.

[0052] Thanks to the unique "planar mounting + physical bending" process of this embodiment, the physical dimensions of the final product are extremely compressed. Traditional through-beam packaging requires maintaining a certain structural strength between two vertical supports and accommodating the flow channels of the packaging mold. Its thickness is typically between 2.5mm and 4.0mm, and its width is limited by the side-by-side arrangement of the two supports, usually above 3.0mm. However, the optocoupler manufactured in this embodiment can have a very compact bending area, and the single lead frame does not require additional support structures. Its thickness can be easily controlled to less than or equal to 1.8mm, and even less than 1.0mm in some ultra-thin models. Its width is mainly determined by the width of the discrete device itself. With the precise lead frame design, miniature optocouplers with a width of less than or equal to 1mm are entirely achievable.

[0053] By utilizing a physical bending process, this solution breaks through the size limitations of traditional dual-support stacked packaging. A thickness of 1.8mm and a width of 1mm achieve extreme miniaturization, far superior to existing products with thicknesses exceeding 2.0mm and widths exceeding 3.0mm, meeting the space-sensitive application requirements of wearable devices, ultra-thin laptops, and other applications.

[0054] Example 2 This embodiment provides an alternative optical path layout for the optocoupler and its manufacturing method, namely, a reflective coupling. Unlike the direct-orbiting design in Embodiment 1, this embodiment utilizes the principle of reflection to guide the optical path. This is suitable for some special packaging structure designs, such as scenarios where it is necessary to further reduce the thickness or increase the optical path length to improve anti-interference capabilities.

[0055] The main difference between the manufacturing method of this embodiment and that of Embodiment 1 lies in step S3 and the pretreatment of the substrate. The remaining steps S1, S2, S4 and S5 are basically the same as those of Embodiment 1, and will not be repeated here. The focus is on explaining the differences.

[0056] Pretreatment of the substrate: In step S1 or step S2, a reflective surface is formed on the planar substrate.

[0057] Method 1: High-reflectivity coating. A high-reflectivity metal layer, such as silver, aluminum, or gold, is deposited on the area of ​​the planar substrate intended to serve as the reflective surface through electroplating or sputtering. To prevent oxidation, a transparent protective layer is usually applied over this metal layer. This reflective surface is located on the substrate body.

[0058] Method 2: Miniature Reflector. In the planar mounting stage of step S2, in addition to mounting the infrared light-emitting device and the photosensitive receiving device, a pre-prepared miniature reflector can also be mounted between them. This miniature reflector can be a 45-degree angle prism or a reflector attached to the base.

[0059] In step S3, the planar substrate is physically bent so that the infrared light-emitting device and the photosensitive receiver are tilted at a specific angle, so that the light emitted by the infrared light-emitting device shines on the reflective surface and is reflected by the reflective surface to the light-receiving surface of the photosensitive receiver.

[0060] For example, an infrared light-emitting device is mounted on a first region of a planar substrate, a photosensitive receiving device is mounted on a second region of the substrate, and a reflective surface is disposed between the first and second regions. Using a physical bending fixture, the first region is bent upwards at a 45-degree angle, and the second region is also bent upwards at a 45-degree angle, or one region is kept horizontal while the other is bent at a 90-degree angle and deflected.

[0061] In this way, the light emitted by the infrared light-emitting device is no longer directed vertically upwards, but is emitted at a 45-degree angle and projected onto the reflective surface on the intermediate substrate. After the reflective surface reflects the light 90 degrees, it enters the receiving surface of the photosensitive receiving device, which is also tilted at 45 degrees.

[0062] Reflective structures allow light paths to be deflected, which makes the arrangement of light-emitting and receiving devices on the substrate more flexible, no longer limited to the vertical stacking pattern; in some flat packaging designs, reflective structures can help to further compress the Z-axis height because the reflective surface can be designed to be parallel to the substrate plane.

[0063] By introducing reflection, the path length of light traveling inside the device can be increased without increasing the package size. This is particularly valuable in applications that require filtering out interference of specific wavelengths or utilizing the attenuation effect of light in a medium.

[0064] Although the optical path has become reflective, the core process still involves using physical bending to change the device angle. By utilizing a semi-etched hinge structure, the precision of 45 degrees or other specific reflection angles can still be accurately controlled, ensuring the accuracy of optical path alignment.

[0065] Compared to embedding complex glass prisms within the package, using the substrate's own metal plating or attaching simple reflectors is extremely low-cost and does not require additional processing steps, thus maintaining the high cost-effectiveness advantage of this application.

[0066] Unlike existing technologies, this application discloses a discretely packaged optocoupler and its manufacturing method. The embodiments of this application achieve low-cost manufacturing and pre-screening of devices simultaneously through discrete device packaging. Precise three-dimensional optical path construction is achieved using planar mounting and physical bending, resulting in a simple and efficient process. Low-loss light transmission and structural fixation are achieved through filling with a transparent light-guiding colloid with matching refractive index. Finally, light-shielding packaging ensures high isolation. This solution completely abandons traditional double-support stacking, light guide sheets, or complex adhesive mechanical peeling methods, avoiding adhesive residue, tedious debonding, and fragmentation problems caused by mechanical stress. It also greatly simplifies the process flow and significantly improves peeling yield and production efficiency. This manufacturing method only requires conventional LED packaging production lines, SMT equipment, and bending equipment, eliminating the need for expensive multi-type lasers working together, significantly reducing equipment investment and operating costs.

[0067] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for manufacturing an optocoupler, characterized in that, include: Step S1: Separately package the infrared light-emitting chip and the photosensitive receiving chip to form an infrared light-emitting device and a photosensitive receiving device with independent pads; Step S2: The infrared light-emitting device and the photosensitive receiving device are soldered onto the same planar substrate in a planar mounting manner, at which time the light emitting surface and the light receiving surface of both face the same side of the planar substrate; Step S3: Physically bend the planar substrate to transform the infrared light-emitting device and the photosensitive receiving device from a planar layout to a three-dimensional layout, and optically align the light emitting surface and the light receiving surface with each other; Step S4: Fill the space between the light emitting surface of the infrared light-emitting device and the light receiving surface of the photosensitive receiving device with a transparent light-guiding colloid; Step S5: Cover the outside of the three-dimensional structure formed in step S3 with a light-shielding encapsulating colloid, exposing only the pins for external connection.

2. The manufacturing method according to claim 1, characterized in that, In step S2, the step of soldering the infrared light-emitting device and the photosensitive receiving device onto the same planar substrate in a planar mounting manner includes: Using a reflow soldering process, the bottom pads of the infrared light-emitting device and the photosensitive receiving device are respectively soldered to the corresponding pre-set pads on the planar substrate using solder paste.

3. The manufacturing method according to claim 1, characterized in that, The planar substrate is a metal lead frame. The metal lead frame has its material thickness reduced by a semi-etching process in a preset bending area to form a hinge structure with extensibility.

4. The manufacturing method according to claim 3, characterized in that, In step S3, a fixture is used to apply mechanical force to the metal lead frame along the hinge structure, and the area where the infrared light-emitting device and the photosensitive receiving device are mounted is rotated by a specific angle along the bending line.

5. The manufacturing method according to claim 4, characterized in that, In step S3, the specific angle is 90 degrees. By monitoring real-time force feedback, the bending angle is controlled within 90 degrees ± 1 degree, so that the light emitting surface and the light receiving surface form a direct facing arrangement.

6. The manufacturing method according to claim 1, characterized in that, The planar substrate is provided with a reflective surface; In step S3, the planar substrate is physically bent so that the infrared light-emitting device and the photosensitive receiving device are tilted at a specific angle, so that the light emitted by the infrared light-emitting device shines on the reflective surface and is reflected by the reflective surface to the light-receiving surface of the photosensitive receiving device.

7. The manufacturing method according to claim 6, characterized in that, The reflective surface is a high-reflectivity coating formed on the planar substrate in step S1 or step S2, or a miniature reflector mounted on the planar substrate.

8. The manufacturing method according to claim 1, characterized in that, In step S4, the refractive index of the transparent light guide colloid is between 1.4 and 1.6 to match the refractive index of the window material of the infrared light-emitting device and the photosensitive receiving device, thereby reducing Fresnel reflection loss.

9. The manufacturing method according to claim 1, characterized in that, In step S4, the transparent light guide colloid is injected through a dispensing process. The transparent light guide colloid fills the gap in the optical path under capillary action and is cured by heating or ultraviolet irradiation to form a solid light transmission medium.

10. The manufacturing method according to claim 1, characterized in that, In step S5, the light-shielding encapsulating colloid is an epoxy resin filled with carbon black, which is coated around the three-dimensional structure by molding or coating process, covering all light-transmitting areas except the pins.

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