Optical coupling structure and manufacturing method thereof

Abstract

The invention provides an optical coupling structure and a manufacturing method thereof. The optical coupling structure comprises a first circuit board, at least one light-emitting element, a second circuit board and at least one light-receiving element. Wherein at least one light-emitting element is arranged on and electrically connected to the first circuit board, and at least one light-receiving element is arranged on and electrically connected to the second circuit board. The at least one light-emitting element is opposite to the at least one light-receiving element, the light-emitting element can form a light signal according to an input signal, and the light signal can be absorbed by the light-receiving element and then converted into an output signal.

Description

Technical Field

[0001] This invention relates to an optical coupling structure and its manufacturing method, and particularly to an optical coupling structure and its manufacturing method that simultaneously has a light-emitting element and a light-receiving element on a single element. Background Technology

[0002] An optocoupler is an electronic component that uses light to transmit electrical signals. It typically contains two chips with different functions: a light-emitting diode (LED) and a photodiode (PDD). For example... Figure 1 As shown, traditional optocouplers 1 can generally be divided into left-right arrangement packaging structures and top-bottom arrangement packaging structures. For a left-right arrangement packaging structure, the light-emitting diode 10 and the photodiode 20 are arranged in opposite left-right positions inside the optocoupler 1. Conversely, for a top-bottom arrangement packaging structure, the light-emitting diode 10 and the photodiode 20 are arranged in opposite top-bottom positions inside the optocoupler 1. However, regardless of whether the optocoupler 1 is left-right or top-bottom arranged, after the light-emitting diode 10 and the photodiode 20 are each separately mounted onto the lead frame 30, a mold must be fabricated to encapsulate the light-emitting diode 10, the photodiode 20, and the lead frame 30 into a final component structure. The resulting optocoupler typically contains only one light-emitting diode 10 and one corresponding photodiode 20, resulting in an overly simplistic circuit structure that cannot adapt to different circuit requirements. Furthermore, the lead frame and molded packaging structure in this type of traditional optocoupler often results in a considerable size, which is detrimental to the miniaturization requirements of electronic components. Therefore, the aforementioned traditional optocouplers are characterized by limited functionality and large size, which hinders the diversification and miniaturization requirements of circuit applications and is a problem that the industry urgently needs to address. Summary of the Invention

[0003] The main objective of this invention is to provide an innovative optical coupling structure and its manufacturing method. The integrated array scheme can not only meet the needs of various combinations of optical coupling elements in circuit design, but also the improved packaging method can meet the development trend of element miniaturization, which is conducive to increasing production speed and reducing costs.

[0004] To achieve the above objectives, the present invention provides an optical coupling structure comprising a first circuit board, at least one light-emitting element, a second circuit board, and at least one light-receiving element. The at least one light-emitting element is disposed on and electrically connected to the first circuit board, and the at least one light-receiving element is disposed on and electrically connected to the second circuit board. The at least one light-emitting element and the at least one light-receiving element are opposite to each other. The light-emitting element can generate an optical signal in response to an input signal, and the optical signal can be absorbed by the light-receiving element and then converted into an output signal.

[0005] In one embodiment of the optical coupling structure of the present invention, a transparent colloid is further included, which is filled between the first circuit board and the second circuit board and covers the at least one light-emitting element and the at least one light-receiving element.

[0006] In one embodiment of the optical coupling structure of the present invention, the transparent colloid is selected from one of the groups consisting of epoxy resin, silicone, polyurethane (PU), and polyimide (PI).

[0007] In one embodiment of the optical coupling structure of the present invention, at least one electronic functional element is disposed and electrically connected to one of the first circuit board or the second circuit board.

[0008] In one embodiment of the optical coupling structure of the present invention, an isolation sheet is further included, disposed between the first circuit board and the second circuit board, such that the at least one light-emitting element and the at least one light-receiving element are disposed on two opposite sides of the isolation sheet.

[0009] In one embodiment of the optical coupling structure of the present invention, the insulating sheet is selected from one of the groups consisting of quartz, acrylic, glass, polycarbonate, and polyether ether ketone (PEEK).

[0010] In one embodiment of the optical coupling structure of the present invention, the at least one light-receiving element is a flip-chip photodiode.

[0011] In one embodiment of the optical coupling structure of the present invention, the at least one light-emitting element is a flip-chip light-emitting diode.

[0012] In one embodiment of the optical coupling structure of the present invention, the first circuit board and the second circuit board each have a printed circuit.

[0013] In one embodiment of the optical coupling structure of the present invention, the first circuit board and the second circuit board are one of a ceramic substrate, a metal substrate, and a polyimide substrate.

[0014] To achieve the above objectives, the present invention provides a method for manufacturing an optical coupling structure, comprising the following steps: First, providing at least one light-emitting element disposed on and electrically connected to a first circuit board. Second, providing at least one light-receiving element disposed on and electrically connected to a second circuit board. Next, inverting either the first circuit board or the second circuit board so that the at least one light-emitting element and the at least one light-receiving element are opposite to each other. Next, providing a transparent colloid, filling the space between the first and second circuit boards to cover the at least one light-emitting element and the at least one light-receiving element. Finally, cutting the first and second circuit boards to form at least one optical coupling unit, wherein the at least one optical coupling unit includes the at least one light-emitting element and the at least one light-receiving element.

[0015] In one embodiment of the optical coupling structure manufacturing method of the present invention, it further includes providing at least one electronic functional element disposed on and electrically connected to one of the first circuit board or the second circuit board.

[0016] In one embodiment of the optical coupling structure manufacturing method of the present invention, a separator is provided and disposed between the first circuit board and the second circuit board, such that the at least one light-emitting element and the at least one light-receiving element are disposed on two opposite sides of the separator.

[0017] Other objects of the present invention, as well as the technical means and implementation methods of the present invention, will be understood by those skilled in the art upon referring to the accompanying drawings and the embodiments described below. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of two traditional optical coupling elements;

[0019] Figures 2 to 4 A cross-sectional schematic diagram of the optical coupling structure in one embodiment of the present invention;

[0020] Figure 5 This is a cross-sectional schematic diagram of the optical coupling structure in one embodiment of the present invention;

[0021] Figure 6 This is a cross-sectional schematic diagram of the optical coupling structure in one embodiment of the present invention;

[0022] Figure 7 This is a cross-sectional schematic diagram of the optical coupling structure in one embodiment of the present invention;

[0023] Figures 8 to 9 A cross-sectional schematic diagram of the optical coupling structure in another embodiment of the present invention;

[0024] Figure 10 This is a cross-sectional schematic diagram of the optical coupling structure in another embodiment of the present invention; and

[0025] Figure 11 This is a schematic diagram of the process steps for the optical coupling structure in one embodiment of the present invention.

[0026] Explanation of reference numerals in the attached figures

[0027] 1 Optical coupling element

[0028] 10 Light Emitting Diodes

[0029] 20 Photodiode

[0030] 30 Conductor frame

[0031] 100 Optical Coupler Unit

[0032] 110 First Circuit Board

[0033] 112 electrode

[0034] 114 electrodes

[0035] 120 Second Circuit Board

[0036] 122 electrode

[0037] 124 electrodes

[0038] 126 Glue Dispensing Hole

[0039] 128 Exhaust port

[0040] 210 Light-emitting element

[0041] 220 light-receiving element

[0042] 230 Electronic functional components

[0043] 310 Transparent Colloid

[0044] 320 isolation sheet. Detailed Implementation

[0045] The following embodiments will explain the content of this invention. These embodiments are not intended to limit the implementation of this invention to any specific environment, application, or special method described in the embodiments. Therefore, the descriptions of the embodiments are merely illustrative of the invention and not intended to limit it. It should be noted that in the following embodiments and drawings, elements not directly related to this invention have been omitted and are not shown, and the dimensional relationships between the elements in the drawings are for ease of understanding only and are not intended to limit the actual scale.

[0046] This invention discloses an optical coupling structure and its manufacturing method. Please refer to [link / reference]. Figure 2First, a first circuit board 110 and a plurality of light-emitting elements 210 are provided, with each light-emitting element 210 disposed on and electrically connected to the first circuit board 110. Next, a second circuit board 120 and a plurality of light-receiving elements 220 are provided, with each light-receiving element 220 disposed on and electrically connected to the second circuit board 120. In specific embodiments, the first circuit board 110 and the second circuit board 120 can be, for example, a ceramic substrate, a metal substrate, a polyimide substrate, etc., but are not limited thereto. In addition to having printed circuits (not shown) with copper foil conductive patterns on their surfaces, allowing for the design of corresponding printed circuit patterns to meet different circuit requirements, the first circuit board 110 and the second circuit board 120 also possess a certain structural strength, and can be directly used as supports for the light-emitting elements 210 and the light-receiving elements 220 in the optical coupling structure of this invention, replacing the metal lead frame in traditional optical coupling elements and achieving the requirement of element miniaturization.

[0047] On the other hand, the light-emitting element 210 can be, for example, a light-emitting diode (LED), whose emission band can be adjusted according to specific implementation requirements. For example, it can be an infrared LED with an emission band of 800–950 nanometers (nm). The light-receiving element 220 can be, for example, a photodiode or phototransistor based on silicon, which uses the base current of the light-input transistor to sense a range of 400–1100 nanometers (nm). It should be noted that, in the preferred embodiment of the present invention, to meet the requirements of element miniaturization, the light-emitting element 210 is a flip-chip LED, and the light-receiving element 220 is a flip-chip photodiode.

[0048] Please see Figure 3 The display shows that after either the first circuit board 110 or the second circuit board 120 is reversed, the relative positions between the two circuit boards are adjusted and fixed by setting an appropriate clamping fixture, so that the light-emitting element 210 on the first circuit board 110 and the light-receiving element 220 on the second circuit board 120 are in a relative position to each other. The relative position of the light-emitting element 210 and the light-receiving element 220 allows the light signal emitted by the light-emitting element 210 in response to an input signal to be smoothly received by the light-receiving element 220, converted into an output signal, and then output to the outside.

[0049] It should be noted that, to facilitate subsequent packaging processes, this invention specifically provides several through holes of different diameters on either the first circuit board 110 or the second circuit board 120, serving as potting holes and venting holes respectively. For details, please refer to... Figure 4In the embodiment shown in the figure, the first circuit board 110 is disposed below the two circuit boards, and the second circuit board 120 is disposed above the two circuit boards. Therefore, in this embodiment, the second circuit board 120 is provided with several potting holes 126 and venting holes 128 penetrating the upper and lower surfaces of the circuit board. In other embodiments, the first circuit board can be disposed above the second circuit board, so that the aforementioned potting holes and venting holes are disposed on the first circuit board in the upper position. In addition, the potting holes 126 are used to fill the glue, so the hole diameter is relatively large, while the venting holes 128 are used for venting during glue filling and for observing the filling status, so the hole diameter is relatively small. Figure 4 As shown, transparent adhesive 310 is filled between the first circuit board 110 and the second circuit board 120 through the potting hole 126, and the vent hole 128 is used to confirm whether the transparent adhesive 310 has been completely filled and fully covers the light-emitting element 210 and the light-receiving element 220. Specifically, the transparent adhesive 310 can be selected from one of the groups composed of epoxy resin, silicone resin, polyurethane (PU), and polyimide (PI).

[0050] Next, please refer to both. Figure 4 and Figure 5 The transparent colloid filling process is followed by a thermosetting process. The structure is then baked and hardened before cutting. When cutting the first circuit board 110 and the second circuit board 120, the cutting path can be along the potting holes 126 and vent holes 128 on the circuit boards. Figure 4 The direction shown by the dashed lines is used to form multiple optically coupled units 100. For example... Figure 5 As shown, after cutting, each optical coupling unit 100 includes at least one light-emitting element 210 and at least one light-receiving element 220. Furthermore, using electrodes 112, 114, 122, and 124 arranged on the surfaces of the original first circuit board 110 and second circuit board 120, functional testing of individual optical coupling units 100 can be performed in a horizontal or vertical manner by clamping electrodes to confirm whether the light-emitting element 210 and light-receiving element 220 in each individual optical coupling unit can operate normally. In a specific embodiment, an opaque adhesive (not shown) can be covered on the exposed transparent adhesive side of the cut optical coupling unit 100 to prevent external light from interfering with the operation of the optical coupling unit and to prevent light generated by the internal light-emitting element of the optical coupling unit from leaking out.

[0051] Figure 5One difference between the optical coupling unit 100 of the present invention and conventional optical coupling elements is that the present invention uses a printed circuit board with supporting strength to replace the metal lead frame of conventional optical coupling elements. Therefore, the optical coupling unit of the present invention has a smaller and more miniaturized size after packaging. In addition, the present invention can utilize different circuit designs of the printed circuit board to create diverse optical coupling structures. That is, the present invention can increase or decrease the number of light-emitting elements and light-receiving elements in individual optical coupling units according to the design requirements of actual optical coupling products, such as... Figure 6 The illustrated optical coupling unit 100 has two light-emitting elements 210 paired with one light-receiving element 220. Similarly, different variations can be made in other embodiments. For example, various optical coupling structures, such as several light-emitting elements paired with one light-receiving element, one light-emitting element paired with several light-receiving elements, and several light-emitting elements paired with several light-receiving elements, are all within the scope of the specific application of this invention and will not be elaborated here.

[0052] like Figure 7 As shown, the present invention can also, according to the actual application requirements of the optical coupling product, provide one or more other electronic functional components 230 on the first circuit board and / or the second circuit board, and electrically connect them to the light-emitting element or light-receiving element of the first circuit board or the second circuit board. For example, this electronic functional component can be a driver chip or a control chip, etc., so that one or more electronic functional components 230 together with the light-emitting element 210 and the light-receiving element 220 form a micro-circuit module, which can make the function of the optical coupling unit 100 of the present invention more diversified and further achieve the requirement of miniaturization of the overall component size.

[0053] Please refer to both together. Figures 8 to 10 In another embodiment of the present invention, to enhance the high voltage resistance and noise interference immunity of the optical coupling element, an isolation plate 320 can be provided between the first circuit board 110 and the second circuit board 120 in the optical coupling unit 100, so that the light-emitting element 210 and the light-receiving element 220 are respectively disposed on two opposite sides of the isolation plate 320. Specifically, the isolation plate can be selected from one of the group consisting of quartz, acrylic, glass, polycarbonate, and polyether ether ketone (PEEK).

[0054] Please see Figure 11The diagram illustrates the steps of manufacturing the optical coupling structure of the present invention. First, in step S01, at least one light-emitting element is provided and disposed on and electrically connected to a first circuit board. Next, in step S02, at least one light-receiving element is provided and disposed on and electrically connected to the second circuit board. Then, in step S03, either the first or second circuit board is reversed so that the light-emitting element and the light-receiving element are facing each other. In step S04, a transparent colloid is provided and filled between the first and second circuit boards to cover the light-emitting element and the light-receiving element. Finally, in step S05, the first and second circuit boards are cut to form at least one optical coupling unit, wherein the optical coupling unit includes at least one light-emitting element and at least one light-receiving element. Detailed descriptions of the above units can be found in the foregoing description and will not be repeated here.

[0055] The above embodiments are merely illustrative of implementation schemes of the present invention and to explain the technical features of the present invention, and are not intended to limit the scope of protection of the present invention. Any changes or equivalent arrangements that can be easily made by those skilled in the art are within the scope of the present invention, and the scope of protection of the present invention should be determined by the claims.

Claims

1. An optical coupling structure, comprising: First circuit board; At least one light-emitting element is disposed on and electrically connected to the first circuit board; A second circuit board; and At least one light-receiving element is disposed and electrically connected to the second circuit board; in, The at least one light-emitting element and the at least one light-receiving element are opposite to each other. The at least one light-emitting element can generate an optical signal in response to an input signal. The optical signal can be absorbed by the at least one light-receiving element and then converted into an output signal.

2. The optical coupling structure as described in claim 1 further comprises a transparent colloid, which fills the space between the first circuit board and the second circuit board and covers the at least one light-emitting element and the at least one light-receiving element.

3. The optical coupling structure as described in claim 2, wherein the transparent colloid is selected from one of the groups consisting of epoxy resin, silicone resin, polyurethane, and polyimide.

4. The optical coupling structure as claimed in claim 1 further includes at least one electronic functional element disposed and electrically connected to one of the first circuit board or the second circuit board.

5. The optical coupling structure as described in claim 1 further includes an isolation sheet disposed between the first circuit board and the second circuit board, such that the at least one light-emitting element and the at least one light-receiving element are disposed on two opposite sides of the isolation sheet.

6. The optical coupling structure as claimed in claim 5, wherein the isolator is selected from one of the group consisting of quartz, acrylic, glass, polycarbonate, and polyetheretherketone.

7. The optical coupling structure as claimed in claim 1, wherein the at least one light-receiving element is a flip-chip photodiode.

8. The optical coupling structure as claimed in claim 1, wherein the at least one light-emitting element is a flip-chip light-emitting diode.

9. The optical coupling structure as claimed in claim 1, wherein the first circuit board and the second circuit board each have a printed circuit.

10. The optical coupling structure as claimed in claim 1, wherein the first circuit board and the second circuit board are one of a ceramic substrate, a metal substrate, and a polyimide substrate.

11. A method for manufacturing an optical coupling structure, comprising: At least one light-emitting element is provided and disposed on and electrically connected to a first circuit board; At least one light-receiving element is provided and disposed on and electrically connected to a second circuit board; Reverse either the first circuit board or the second circuit board so that the at least one light-emitting element and the at least one light-receiving element are facing each other; A transparent colloid is provided to fill the space between the first circuit board and the second circuit board to cover the at least one light-emitting element and the at least one light-receiving element; and The first circuit board and the second circuit board are cut to form at least one optical coupling unit, wherein the at least one optical coupling unit includes the at least one light-emitting element and the at least one light-receiving element.

12. The manufacturing method of claim 11 further comprises providing at least one electronic functional element disposed on and electrically connected to one of the first circuit board or the second circuit board.

13. The manufacturing method of claim 11 further includes providing an isolation sheet disposed between the first circuit board and the second circuit board, such that the at least one light-emitting element and the at least one light-receiving element are disposed on two opposite sides of the isolation sheet.

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