Injection mold and production method for an optical fiber receiving device

Abstract

The application provides a production method of an optical fiber receiving device, which comprises the following steps: initially preheating a solid epoxy resin; heating an injection mold; placing a frame with a chip into a mold cavity of the heated injection mold, and performing mold closing; adding the preheated epoxy resin cake, pressing the epoxy resin cake into the mold cavity through a pressing rod of an injection machine, discharging air in the mold cavity through an exhaust passage, and performing high-temperature curing for a period of time; stopping air discharge, obtaining the optical fiber receiving device, and placing the optical fiber receiving device at room temperature for cooling; performing post-curing treatment, filling a protective gas in a high-temperature oven; performing high-low temperature cycle treatment, and screening out unqualified optical fiber receiving devices. The application solves the problems of low qualification rate and reliability of the device produced by the traditional packaging process, and reduces the requirement for the consistency of raw materials, improves the qualification rate of products, and reduces the cost effect.

Description

Technical Field

[0001] This invention relates to the field of optical fiber receiver manufacturing technology, and in particular to a method for manufacturing an optical fiber receiver. Background Technology

[0002] Currently, fiber optic receivers have the following problems: the epoxy resin material used for packaging is expensive; the yield and reliability of devices produced under traditional packaging processes are poor; the key processes in the packaging of fiber optic receivers include molding and post-curing. In the traditional molding process, air bubbles are easily generated in the device. When air bubbles exist in the transmitting and detecting areas of the fiber optic receiver, they will affect the transmission characteristics of the optical signal during operation. In the subsequent soldering process, air bubbles are prone to expansion or rupture due to heat, which can damage the circuitry in the chip. They are also prone to corrosion in the later stages, leading to early failure. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an injection mold and production method for an optical fiber receiver, which solves the problems of low yield and reliability in existing technologies.

[0004] like Figure 1 As shown, according to an embodiment of the present invention, a method for manufacturing an optical fiber receiver includes the following steps:

[0005] Step 1: Place the solid epoxy resin cake into a high-frequency preheater for preheating to obtain a preheated epoxy resin cake.

[0006] Heating the injection mold of the optical fiber receiver;

[0007] The chip-containing frame is placed into the cavity of the injection mold, and the upper and lower molds of the injection mold are closed.

[0008] Add the preheated epoxy resin cake into the heating port of the injection mold, press the epoxy resin cake into the mold cavity through the pressure bar of the injection molding machine, and expel the air in the mold cavity through the venting channel for high-temperature curing for a period of time.

[0009] Stop venting, open the injection mold to obtain the encapsulated fiber optic receiver, and place it at room temperature for cooling to obtain the cooled fiber optic receiver.

[0010] After cooling, the optical fiber receiving device is placed in a high-temperature oven for post-curing treatment, and the high-temperature oven is filled with protective gas.

[0011] The post-curing fiber optic receiver is placed in a temperature cycling test chamber for high and low temperature cycling treatment. After the treatment is completed, the finished product is obtained.

[0012] Preferably, in the step of placing the solid epoxy resin cake into a high-frequency preheater for preheating to obtain a preheated epoxy resin cake, the preheating temperature is 60~80℃ and the preheating time is 10~30 seconds.

[0013] Preferably, in the step of heating the injection mold of the optical fiber receiver, the heating temperature is 140~160℃.

[0014] Preferably, in the step of placing the chip-bearing frame into the mold cavity of the injection mold and closing the upper and lower molds of the injection mold, the emitting or probing spherical surface of the chip-bearing frame is kept facing the lower mold of the injection mold.

[0015] Preferably, in the step of adding preheated epoxy resin cake from the injection hole of the injection mold, pressing the epoxy resin cake into the mold cavity through the pressure bar of the injection molding machine, venting the air in the mold cavity through the venting channel, and performing high-temperature curing for a period of time, the high-temperature curing temperature is 140~160℃ and the curing time is 2~4 minutes.

[0016] Preferably, in the step of placing the cooled optical fiber receiving device into a high-temperature oven for post-curing treatment, and filling the high-temperature oven with a protective gas, the protective gas is nitrogen. During the post-curing treatment, the temperature is increased by 1°C per minute until it reaches between 120°C and 140°C. The pre-treatment lasts for 2 to 3 hours, and then the temperature is increased to 140°C to 150°C for curing for 5 to 6 hours. After that, the temperature is decreased by 1°C per minute until it reaches room temperature.

[0017] Preferably, in the step of placing the post-cured optical fiber receiver into a temperature cycling test chamber for high and low temperature cycling treatment, and obtaining the finished product after the treatment, the high temperature of the high and low temperature cycling treatment is set to 85°C, the low temperature of the high and low temperature cycling treatment is set to -40°C, the cycle time of the high and low temperature cycling treatment is 1 to 4 hours per cycle, and the optical fiber receiver is stopped after 3 to 5 cycles.

[0018] An injection mold for an optical fiber receiver includes an upper mold and a lower mold. When the upper mold and the lower mold are closed, they form a mold cavity. The mold cavity is used to hold a chip frame to be injected. The upper mold has a through-hole for ventilation. The ventilation channel is connected to a vacuum exhaust pipe. The upper mold also has an injection hole.

[0019] Preferably, at least two venting channels are provided, which are evenly distributed around the injection hole.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. This invention utilizes a high-frequency preheating machine to preheat the epoxy resin cake, initially softening the epoxy resin and ensuring uniform heating during subsequent curing. The preheated epoxy resin cake has a certain fluidity, easily expelling air bubbles from the epoxy resin, and curing synchronously and uniformly during the polymerization reaction. When using an injection molding machine, the transmitting or detecting spherical surface of the optical fiber receiver is oriented towards the lower mold of the injection mold. Since air flows upward during heating, air bubbles will rise to the upper part, thus avoiding the formation of air bubbles in the transmitting or detecting spherical surface area, which would affect the photoelectric transmission characteristics. This reduces the requirements for raw material consistency, improving product qualification rate while reducing costs.

[0022] 2. During the post-curing process, a protective gas is used to prevent the optical fiber receiving device from oxidizing with oxygen in the air during the curing process. In the post-curing step, a temperature control method of slow cooling and slow heating is adopted to prevent the epoxy resin from expanding rapidly.

[0023] 3. By adding high and low temperature cycling treatment, we can screen out fiber optic receiver devices whose circuits are prone to failure in early chips, improve the reliability of fiber optic receiver devices, avoid premature failure during later use by customers, and enhance product quality and customer reputation.

[0024] 4. An venting channel is opened in the upper mold of the injection mold. The venting channel is connected to a vacuum tube. During molding, the venting channel is opened and the air in the mold cavity is removed through the vacuum tube. This prevents excessive air in the mold cavity from generating bubbles inside the device when the epoxy resin cures. This increases the pass rate of the fiber optic receiver device from about 60% to over 90%, significantly improving the pass rate and indirectly reducing production costs. Attached Figure Description

[0025] Figure 1 This is a flowchart of the production method according to an embodiment of the present invention.

[0026] Figure 2 This is a cross-sectional view of an injection mold according to another embodiment of the present invention.

[0027] In the above attached diagram: 1. Upper mold; 2. Lower mold; 3. Mold cavity; 4. Venting channel; 5. Vacuum vent pipe; 6. Injection hole. Detailed Implementation

[0028] To make the technical problem to be solved, the technical solution, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0029] On one hand, the present invention provides a method for manufacturing an optical fiber receiver, comprising the following steps:

[0030] Step 1: Place the solid epoxy resin cake into a high-frequency preheater for preheating to obtain a preheated epoxy resin cake.

[0031] Step 2: Heat the injection mold of the optical fiber receiver;

[0032] Step 3: Place the frame with the chip into the cavity 3 of the injection mold, and close the upper mold 1 and lower mold 2 of the injection mold.

[0033] Step 4: Add the preheated epoxy resin cake into the injection hole 6 of the injection mold, press the epoxy resin cake into the mold cavity 3 through the pressure bar of the injection molding machine, and expel the air in the mold cavity 3 through the venting channel 4, and perform high-temperature curing for a period of time.

[0034] Step 5: Stop venting, open the injection mold to obtain the encapsulated fiber optic receiver, and place it at room temperature for cooling to obtain the cooled fiber optic receiver.

[0035] Step 6: Place the cooled optical fiber receiver into a high-temperature oven for post-curing treatment. The high-temperature oven is filled with protective gas.

[0036] Step 7: Place the post-cured fiber optic receiver into a temperature cycling test chamber for high and low temperature cycling treatment. The finished product is obtained after this process. Step 1 uses a high-frequency preheater to preheat the epoxy resin cake, initially softening it. This ensures uniform heating during subsequent curing. The preheated epoxy resin cake has a certain fluidity, easily expelling air bubbles and allowing for simultaneous and uniform curing during the polymerization reaction. Step 3: During injection molding, the transmitting or detecting spherical surface of the fiber optic receiver is positioned towards the lower mold 2. Since air flows upwards during heating, air bubbles rise to the top, preventing them from affecting the photoelectric transmission characteristics. This reduces the requirement for raw material consistency and significantly lowers production costs. Step 6: During post-curing, a protective gas is filled to prevent oxidation of the fiber optic receiver with oxygen in the air during curing. Slow cooling and slow heating are used in the post-curing step. The temperature control method avoids rapid expansion of epoxy resin; step seven adds high and low temperature cycling treatment to screen out early-stage fiber optic receiver devices whose circuits are prone to failure, improving the reliability of fiber optic receiver devices and preventing premature failure during later use by customers, thus improving product quality and customer reputation. When epoxy resin is used as raw material, the pass rate of the produced fiber optic receiver devices is monitored at around 60%. The pass rate of the fiber optic receiver devices produced by the production method provided by this invention reaches over 90%, significantly improving the pass rate of fiber optic receiver devices. Furthermore, after high and low temperature screening, the failure rate of the optical front receiver devices obtained during welding at a high temperature of around 400℃ is reduced from about 10% to 0.01%, improving the reliability of fiber optic receiver devices.

[0037] In step one, the preheating temperature is 60~80℃, and the preheating time is 10~30 seconds. Preheating softens the epoxy resin cake, making it easier to add to the injection mold later. The softened epoxy resin cake also has a certain degree of fluidity, allowing for uniform and synchronous curing during the subsequent high-temperature curing, thus improving the quality of the optical fiber receiving device.

[0038] In step two, the heating temperature is 140~160℃. Preheating the injection mold facilitates the addition of epoxy resin cake, preventing it from solidifying inside the mold.

[0039] In step three, the emitting or probing surface of the chip-embedded frame is kept facing the lower mold 2 of the injection mold. The chip and frame are pre-welded together. The frame is used to conduct electrical signals to the chip. The emitting or probing surface of the chip-embedded frame facing the lower mold 2 of the injection mold makes it easier for air bubbles to form in the area of ​​the emitting or probing surface, affecting the photoelectric transmission characteristics and thus the quality of the optical fiber receiving device.

[0040] In step four, the high-temperature curing temperature is 140~160℃, and the curing time is 2~4 minutes. High-temperature curing allows the epoxy resin to encapsulate the chip on the frame, thus encapsulating the chip within the epoxy resin. By evacuating the exhaust channel 4, air in the molding cavity and epoxy resin is eliminated as much as possible, improving the molding success rate of the device.

[0041] In step six, the protective gas is nitrogen. During the post-curing process, the temperature is increased by 1°C per minute until it reaches 120°C~140°C. Pre-treatment lasts 2~3 hours, followed by curing at 140°C~150°C for 5~6 hours. Then, the temperature is decreased by 1°C per minute until room temperature. Nitrogen is preferred as the protective gas because it is chemically stable and does not readily react. The use of the protective gas prevents oxidation reactions between air and the fiber optic receiver, thus reducing its lifespan. During the post-curing process, the heating and cooling stages are performed slowly. Since the epoxy resin cured at high temperature in step four is not fully cured, rapid temperature increases and decreases during post-curing can cause rapid expansion of the epoxy resin, damaging the chip. Slow heating and cooling prevent this rapid expansion.

[0042] In step seven, the high-low temperature cycling treatment is set to 85℃ and the low-temperature treatment to -40℃. The cycle time is 1-4 hours per cycle, and the fiber optic receiver undergoes 3-5 cycles before stopping. Increasing the high-low temperature cycling process helps identify fiber optic receivers that are prone to premature failure due to heat-induced expansion or rupture of air bubbles during subsequent soldering, which could damage the chip's circuitry and lead to corrosion. This improves device reliability and prevents premature failure during later use. After high-low temperature cycling, the failure rate of the fiber optic receiver during soldering at approximately 400℃ decreased from about 10% to 0.01%.

[0043] On the other hand, the present invention also provides an injection mold for an optical fiber receiving device, such as... Figure 2 As shown, the device includes an upper mold 1 and a lower mold 2. When the upper mold 1 and lower mold 2 are closed, they form a mold cavity 3. The mold cavity 3 is used to hold the chip frame to be injection molded. An exhaust channel 4 is provided through the upper mold 1 and communicates with the mold cavity 3. The exhaust channel 4 is connected to a vacuum exhaust pipe 5. The upper mold 1 also has an injection hole 6. The exhaust channel 4 is used to remove air from the mold cavity 3 during curing, preventing air bubbles from forming in the fiber optic receiver during the curing process and improving the molding yield of the fiber optic receiver.

[0044] Furthermore, at least two venting channels 4 are provided, evenly distributed around the injection hole 6. The even distribution of venting channels 3 reduces the air in the epoxy resin and allows air bubbles to be discharged evenly.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for manufacturing an optical fiber receiver, characterized in that, Includes the following steps: The solid epoxy resin cake is placed in a high-frequency preheater for preheating to obtain a preheated epoxy resin cake. Heating the injection mold of the optical fiber receiver; The frame with the chip is placed into the cavity of the heated injection mold, and the upper and lower molds of the injection mold are closed. Add preheated epoxy resin cake into the injection hole of the injection mold, press the epoxy resin cake into the mold cavity through the pressure bar of the injection molding machine, and expel the air in the mold cavity through the venting channel for high temperature curing for a period of time; Stop venting, open the injection mold to obtain the encapsulated fiber optic receiver, and place it at room temperature for cooling to obtain the cooled fiber optic receiver. After cooling, the optical fiber receiving device is placed in a high-temperature oven for post-curing treatment, and the high-temperature oven is filled with protective gas. After post-curing, the optical fiber receiving device is placed in a temperature cycling test chamber for high and low temperature cycling treatment. After the treatment is completed, the finished product is obtained. In the step of placing the chip-bearing frame into the cavity of the injection mold and closing the upper and lower molds of the injection mold, the emitting or probing spherical surface of the chip-bearing frame is kept facing the lower mold of the injection mold.

2. The method for manufacturing the optical fiber receiver as described in claim 1, characterized in that, The solid epoxy resin cake is placed in a high-frequency preheater for preheating to obtain a preheated epoxy resin cake. The preheating temperature is 60~80℃ and the preheating time is 10~30 seconds.

3. The method for manufacturing the optical fiber receiver as described in claim 1, characterized in that, In the step of heating the injection mold of the optical fiber receiving device, the heating temperature is 140~160℃.

4. The method for manufacturing the optical fiber receiver as described in claim 1, characterized in that, In the step of adding preheated epoxy resin cake into the injection hole of the injection mold, pressing the epoxy resin cake into the mold cavity through the pressure bar of the injection molding machine, venting the air in the mold cavity through the venting channel, and curing at high temperature for a period of time, the high temperature curing temperature is 140~160℃ and the curing time is 2~4 minutes.

5. The method for manufacturing the optical fiber receiver as described in claim 1, characterized in that, In the step of placing the cooled optical fiber receiving device into a high-temperature oven for post-curing treatment, and filling the high-temperature oven with a protective gas, the protective gas is nitrogen. During the post-curing treatment, the temperature is increased by 1°C per minute until it reaches between 120°C and 140°C. The pre-treatment lasts for 2 to 3 hours, and then the temperature is increased to 140°C to 150°C for curing for 5 to 6 hours. After that, the temperature is decreased by 1°C per minute until it reaches room temperature.

6. The method for manufacturing the optical fiber receiver as described in claim 1, characterized in that, The post-curing fiber optic receiver is placed in a temperature cycling test chamber for high and low temperature cycling treatment. In the step of obtaining the finished product after the treatment, the high temperature of the high and low temperature cycling treatment is set to 85°C, the low temperature of the high and low temperature cycling treatment is set to -40°C, the cycle time of the high and low temperature cycling treatment is 1 to 4 hours per cycle, and the fiber optic receiver is stopped after 3 to 5 cycles.

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