Common-mode interference resistant optocoupler packaging structure based on condenser lens integration

Abstract

The invention relates to the technical field of optocouplers, in particular to a common-mode interference resistant optocoupler packaging structure based on condenser integration. The projection of the MYLAR collecting lens on a virtual plane completely covers elements on an IR pin and a PT pin base island, 120-degree divergent light of an IR chip is focused to a light spot with the diameter being 0.15 mm, the energy density reaches 230 mW / mm, 8mA driving current can output 18.2 V, a Faraday cage is formed by means of an aluminum plating layer on the surface of the MYLAR collecting lens, stray capacitance is reduced to 0.5 pF under the distance being 0.3 mm, + / -80 V common-mode pulse interference can be resisted, and the requirement for high-power LED light sources is met. The light-transmitting positioning column is arranged along the optical axis of the MYLAR collecting lens, so that the position of a light spot is more accurate and concentrated in a photosensitive area of the PVG, and stable light energy input is provided for the PVG; the technical problems that an existing ternary LED is insufficient in light intensity, the optical axis temperature electric leakage of a quaternary LED is large, and the small size and the anti-interference requirement repel each other are solved.

Description

Technical Field

[0001] This invention relates to the field of optocoupler technology, and in particular to an optocoupler packaging structure based on integrated condenser lens to resist common-mode interference. Background Art

[0002] In the field of automotive-grade Photo MOS Relay optical coupler packaging, there is a fundamental contradiction between the selection of infrared LED chips and the suppression of spatial interference: Quaternary LED chips, while possessing a light power greater than 13mW along the optical axis at a 20mA drive current, have a leakage current greater than 2μA at 85℃ / 5V bias, increasing the risk of failure in 150℃ environments. Ternary LED chips, although having a leakage current less than 500nA, have a light power of only 1mW / 20mA, making it difficult to drive the PVG along the optical axis. Furthermore, in traditional 4-chip opposed packaging, when the LED-PVG spacing is less than 0.8mm, parasitic capacitive coupling results in a common-mode interference tolerance of less than 20dB, leading to failure with ±45V pulses and reflection. The cup-shaped light-concentrating structure suffers from light loss of more than 60% due to multiple reflections in the light path, resulting in a measured light transmission efficiency of less than 35%. This forces the driving current to be above 15mA. In existing solutions, using quaternary LEDs requires adding a heat dissipation structure, which increases the volume by about 40%. Adding an electromagnetic shielding layer reduces the light transmittance by about 50%, and reducing the spacing further worsens capacitive coupling. Therefore, the industry has long faced three technical bottlenecks: insufficient light intensity of ternary LEDs, large leakage current at the optical axis of quaternary LEDs, and the conflict between small size and anti-interference requirements. It is difficult to simultaneously meet the requirements of automotive-grade optical axis temperature reliability, 6600V system driving capability (PVG≥25V), and ±80V common-mode interference suppression. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an optocoupler packaging structure based on integrated condenser lens to resist common-mode interference, which solves the technical problems of insufficient light intensity of existing ternary LEDs, large leakage current at the optical axis of quaternary LEDs, and the conflict between small size and anti-interference requirements.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an optical coupler packaging structure based on a condenser lens integration to resist common-mode interference, comprising a package body, wherein a plurality of IR pins and PT pins are disposed within the package body, an IR chip for emitting light is disposed on the base island of one IR pin, and a PVG for receiving optical signals and converting them into electrical signals is mounted on the base island of one PT pin, the PVG being provided with a photosensitive area for receiving optical signals, and further comprising: A MYLAR condenser lens is placed between the IR chip and the PVG to focus the light emitted by the IR chip onto the photosensitive area of ​​the PVG. A virtual plane parallel to both the plane where the base island of the IR pin is located and the plane where the base island of the PT pin is located, the projections of each component on the base island of the IR pin and the PT pin on the virtual plane are located within the projection of the MYLAR condenser lens on the virtual plane.

[0005] Preferably, the package body is further provided with a positioning component for positioning the MYLAR condenser lens package position according to a preset position.

[0006] Preferably, the positioning component includes a light-transmitting positioning post disposed on the straight line of the optical axis of the MYLAR condenser lens. One end of the positioning post extends towards the IR chip, and the other end extends towards the PVG photosensitive area. The distance between the ends of the positioning posts on both sides of the MYLAR condenser lens and the IR chip and the PVG photosensitive area is less than the gap threshold.

[0007] Preferably, the positioning posts on both sides of the MYLAR condenser lens are pluggable and can be detachably mounted on its surface.

[0008] Preferably, the MYLAR condenser lens has a stepped plane on its curved surface that is perpendicular to the line connecting the IR chip and the PVG photosensitive area, and several positioning blocks are fixed on the stepped plane. The positioning component includes a plurality of connecting rods fixed on at least one of the IR pin and the PT pin. The ends of the plurality of connecting rods are provided with positioning planes located on the same plane. The ends of the connecting rods are fitted with corresponding positioning blocks, and the positioning planes are in contact with the step planes.

[0009] Preferably, the arc lengths of at least three adjacent positioning blocks along the direction of extension of the step plane are not equal.

[0010] Preferably, the connecting rods are all located at the edge of the MYLAR condenser lens.

[0011] By employing the above technical solution, the present invention provides an optical coupling packaging structure based on condenser lens integration to resist common-mode interference, which has at least the following beneficial effects: 1. This invention utilizes a MYLAR focusing lens to completely cover the components on the IR and PT pin islands via virtual plane projection. Optically, it focuses the 120° diverging light of the IR chip onto a Φ0.15mm spot, achieving an energy density of 230mW / mm². This allows an 8mA drive current to output 18.2V, effectively improving the luminous intensity of the ternary LED. The electromagnetic shielding layer utilizes an aluminum plating layer with a thickness of approximately 1μm on the surface of the MYLAR focusing lens to form a continuous Faraday cage, reducing the parasitic capacitance to 0.5pF with a 0.3mm spacing, while also withstanding ±80V common-mode pulse interference.

[0012] 2. This invention sets the light-transmitting positioning post along the optical axis of the MYLAR condenser lens, so that the verticality deviation of the optical path is less than 1°, making the position of the light spot more accurate and concentrated in the photosensitive area of ​​the PVG. The positioning post is made of light-transmitting material, which can greatly reduce the occlusion loss of the optical path and provide a stable light energy input for the PVG.

[0013] 3. This invention achieves a unique assembly angle by using asymmetrically distributed positioning blocks on the stepped plane, eliminating the risk of rotational misalignment of the MYLAR condenser lens during mass production. It also places the connecting rod in the non-optical area at the edge of the condenser lens, allowing the molding resin to shrink and shift to a certain extent without affecting the optical center. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the internal structure of the optocoupler packaging structure of the present invention; Figure 2 This is a side view of the optocoupler packaging structure of the present invention; Figure 3 This is an optical path diagram of the optocoupler packaging structure of the present invention; Figure 4 This is a schematic diagram of the positioning post of the present invention; Figure 5 This is a first schematic diagram of the positioning component of the present invention; Figure 6 This is a second schematic diagram of the positioning component of the present invention; Figure 7 This is a schematic diagram of the stepped plane of the present invention; Figure 8 This is a schematic diagram of the positioning plane of the present invention.

[0015] In the diagram: 1. Package; 2. IR pin; 3. PT pin; 4. IR chip; 5. PVG; 6. MYLAR condenser lens; 7. Positioning assembly; 71. Positioning post; 72. Connecting rod; 73. Positioning plane; 8. Stepped plane; 9. Positioning block. Detailed Implementation

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] To address the technical problems of insufficient luminous intensity in existing ternary LEDs, large leakage current at optical axis temperature in quaternary LEDs, and the conflict between small size and anti-interference requirements, this invention provides an anti-common-mode interference optocoupler packaging structure based on integrated condenser lenses, such as... Figures 1-8 As shown, the package 1 contains several IR pins 2 and PT pins 3. An IR chip 4 for emitting light is mounted on the base island of one of the IR pins 2. A PVG5 for receiving optical signals and converting them into electrical signals is mounted on the base island of one of the PT pins 3. The PVG5 has a photosensitive area for receiving optical signals. The package also includes: A MYLAR condenser lens 6, positioned between IR chip 4 and PVG5, focuses the light emitted from IR chip 4 onto the photosensitive area of ​​PVG5. This focuses the light from IR chip 4, with a divergence angle of 120°, onto a Φ0.15mm spot. Without the MYLAR condenser lens 6, the spot diameter is typically around 0.5mm, increasing the energy density to 230mW / mm². This allows for an output of 18.2V with an 8mA drive current, addressing the issue of insufficient light intensity in ternary LEDs. A virtual plane, parallel to both the plane containing the base islands of IR pin 2 and PT pin 3, projects the components on the base islands of IR pin 2 and PT pin 3 onto this virtual plane. The MYLAR condenser lens 6 is located on... Within the projection on the virtual plane, a continuous shielding layer is formed. MYLAR is a polyester substrate, and the electromagnetic shielding effect is achieved by forming a Faraday cage through the conductive aluminum plating layer on its surface. This ensures that the MYLAR condenser lens 6 can simultaneously perform the dual functions of optical focusing and electromagnetic shielding. With an ultra-small pitch of 0.3mm, the parasitic capacitance is reduced to 0.5pF, compared to 3.2pF before the improvement. It can withstand ±80V common-mode pulse interference. This addresses the technical problem of the conflict between small size and anti-interference requirements. At the same time, ternary LEDs can be used to avoid the risk of quaternary materials having an optical axis temperature leakage greater than 2μA. This effectively solves the existing technical problems of insufficient light intensity of ternary LEDs, large optical axis temperature leakage of quaternary LEDs, and the conflict between small size and anti-interference requirements.

[0018] Figure 2 The image shows a packaging method for this optocoupler. The area enclosed by the blue lines, below the gold lines, is the first packaging; the area enclosed by the blue lines, above the gold lines, is the second packaging; and the purple lines represent the third packaging area, thus completing the entire packaging process.

[0019] Since the MYLAR condenser lens 6 is packaged inside the package body 1, its position needs to be positioned before packaging. The package body 1 is also provided with a positioning component 7 for positioning the MYLAR condenser lens 6 according to the preset position. For the projection of each component on the base island of IR pin 2 and PT pin 3 onto the virtual plane, depending on the distribution of the projection points and the limitations of the package boundary, the MYLAR condenser lens 6 may be spherical, elliptical, or even irregularly shaped. The following discussion will classify the MYLAR condenser lens 6 into two cases: spherical and non-spherical, and discuss the structure of the positioning component 7.

[0020] First, when the MYLAR condenser lens 6 is spherical, the positioning component 7 includes a light-transmitting positioning post 71 positioned along the optical axis of the MYLAR condenser lens 6. This post, for example, can be made of quartz. One end of the positioning post 71 extends towards the IR chip 4, and the other end faces the PVG5 photosensitive area, thus achieving the positioning of the optical axis of the MYLAR condenser lens 6 and constraining the optical path. However, the MYLAR condenser lens 6 still lacks constraint along the optical axis. Therefore, the distance between the ends of the positioning posts 71 on both sides of the MYLAR condenser lens 6 and the IR chip 4 and the PVG5 photosensitive area is made less than the gap threshold, thereby achieving the desired optical path. 6. Positioning on the optical axis ensures that a reasonable spot size is focused onto the PVG5 photosensitive area, thereby improving light efficiency. At this time, the positioning post 71 can be made of a light-transmitting material to reduce light efficiency loss. To further reduce the light efficiency loss caused by the positioning post 71, the positioning posts 71 on both sides of the MYLAR condenser lens 6 can be plugged into its surface. Thus, during packaging, tools such as suction cups or clamps can be used to locate the position of the MYLAR condenser lens 6 through the positioning post 71, and then the positioning post 71 can be removed from the MYLAR condenser lens 6, saving light energy loss and facilitating subsequent continuous use, thus saving costs.

[0021] When the MYLAR condenser lens 6 is non-spherical, if it is positioned using the previous method, there is a lack of constraint on its rotational direction along the optical axis. Therefore, another method is used to fix the MYLAR condenser lens 6. A stepped plane 8 perpendicular to the line connecting the photosensitive areas of the IR chip 4 and PVG5 is provided on the curved surface of the MYLAR condenser lens 6. Several positioning blocks 9 are fixed on the stepped plane 8. The positioning assembly 7 includes several connecting rods 72 fixed to at least one of the IR pin 2 and PT pin 3. That is, the connecting rods 72 can be selectively fixed to either the IR pin 2 or the PT pin 3. The ends of the connecting rods 72 are all provided with positioning planes 73 located on the same plane. The end of the connecting rod 72 engages with the corresponding positioning block 9, and the positioning plane 73 fits against the step plane 8. The fit between the two limits the mounting plane of the MYLAR condenser lens 6. The end of the connecting rod 72 engages with the corresponding positioning block 9 to limit the rotation and movement of the MYLAR condenser lens 6 along the mounting plane. To further achieve mechanical error prevention, the arc lengths of at least three adjacent positioning blocks 9 along the extension direction of the step plane 8 are not equal. At the same time, the material of the MYLAR condenser lens 6 has a certain amount of elastic deformation. By setting the connecting rods 72 at the edges of the MYLAR condenser lens 6, the deformation and displacement of the MYLAR condenser lens 6 caused by the shrinkage of the resin due to the molding stress after encapsulation are prevented, thus protecting the optical center area of ​​the MYLAR condenser lens 6 from deformation.

[0022] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0023] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A common-mode interference-resistant optical coupler packaging structure based on a condenser lens integration, comprising a package (1), wherein a plurality of IR pins (2) and PT pins (3) are disposed within the package (1), wherein an IR chip (4) for emitting light is disposed on the base island of one of the IR pins (2), and a PVG (5) for receiving optical signals and converting them into electrical signals is mounted on the base island of one of the PT pins (3), wherein a photosensitive area for receiving optical signals is disposed on the PVG (5), characterized in that, Also includes: A MYLAR condenser lens (6) is placed between the IR chip (4) and the PVG (5) to focus the light emitted by the IR chip (4) onto the photosensitive area of ​​the PVG (5). A virtual plane parallel to both the plane where the base island of the IR pin (2) and the plane where the base island of the PT pin (3) is located, the projection of each component on the base island of the IR pin (2) and the PT pin (3) on the virtual plane is located within the projection of the MYLAR condenser lens (6) on the virtual plane.

2. The optocoupler packaging structure according to claim 1, characterized in that, The encapsulation body (1) is also provided with a positioning component (7) for positioning the MYLAR condenser lens (6) encapsulation position according to a preset position.

3. The optocoupler packaging structure according to claim 2, characterized in that, The positioning component (7) includes a light-transmitting positioning post (71) set on the straight line of the optical axis of the MYLAR condenser lens (6). One end of the positioning post (71) extends towards the IR chip (4), and the other end extends towards the photosensitive area of ​​the PVG (5). The distance between the ends of the positioning posts (71) on both sides of the MYLAR condenser lens (6) and the photosensitive areas of the IR chip (4) and the PVG (5) is less than the gap threshold.

4. The optocoupler packaging structure according to claim 3, characterized in that, The positioning posts (71) on both sides of the MYLAR condenser lens (6) can be plugged into its surface.

5. The optocoupler packaging structure according to claim 2, characterized in that, The MYLAR condenser lens (6) has a stepped plane (8) perpendicular to the line connecting the photosensitive areas of the IR chip (4) and the PVG (5) on its curved surface, and several positioning blocks (9) are fixed on the stepped plane (8). The positioning component (7) includes a plurality of connecting rods (72) fixed on at least one of the IR pin (2) and the PT pin (3). The ends of the plurality of connecting rods (72) are provided with positioning planes (73) located on the same plane. The ends of the connecting rods (72) are fitted with the corresponding positioning blocks (9), and the positioning planes (73) are in contact with the step planes (8).

6. The optocoupler packaging structure according to claim 5, characterized in that, At least three adjacent positioning blocks (9) have unequal arc lengths along the direction of extension of the step plane (8).

7. The optocoupler packaging structure according to claim 5, characterized in that, The connecting rods (72) are all located at the edge of the MYLAR condenser lens (6).

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