A polarization-tunable plastic-encapsulated semiconductor laser and its packaging method

Abstract

This invention relates to a polarization-tunable plastic-encapsulated semiconductor laser and its packaging method, belonging to the field of optoelectronic lasers. The laser includes a lead frame, a laser chip, a transition heat sink, gold wires, a polarizer, a half-wave plate, and a quarter-wave plate. The lead frame includes a substrate, a plastic-encapsulated frame, leads, and bonding electrodes. The substrate and bonding electrodes are respectively connected to the leads. A slot is provided at the upper end of the substrate for placing the polarizer, half-wave plate, and quarter-wave plate. The plastic-encapsulated frame passes through the leads and wraps around the substrate and bonding electrodes. From top to bottom, the substrate sequentially includes a quarter-wave plate, a half-wave plate, a polarizer, the laser chip, and a transition heat sink. The laser chip is connected to the bonding electrodes via gold wires. This invention achieves interconnection of multiple devices on a single lead frame, enabling arbitrary polarization output.

Description

Technical Field

[0001] This invention relates to a polarization-tunable plastic-encapsulated semiconductor laser and its packaging method, belonging to the fields of optoelectronics and laser technology. Background Technology

[0002] Since their inception, semiconductor lasers have experienced rapid technological development. Compared to other forms of lasers such as solid-state, gas, and liquid lasers, they have gradually emerged in various fields, including manufacturing, communication, sensing, and consumer entertainment, thanks to their advantages such as small size, high efficiency, simple structure, and high reliability, and are increasingly becoming a part of people's daily lives. In practical applications, the polarization state control of the emitted laser is one of the important considerations. The propagation of polarized light and its interaction with matter have been widely applied in optical detection, optical measurement, display technology, data storage, optical communication, materials science, astronomy, and biological research.

[0003] Purposefully controlling the spatial distribution of light polarization can produce new effects and phenomena, thereby expanding and enhancing the functionality of optical systems. A light wave can have different polarization states, and in work and daily life, light with a specific polarization state is often needed. Therefore, we need to use certain methods to change the polarization state of the light wave to obtain the desired specific polarization state. Changing the cavity structure and readjusting the cavity parameters to obtain another polarized light is not only complex but also severely affects the efficiency of the device. Since the polarization state of a light wave is determined by the amplitude ratio and phase difference of its two mutually perpendicular linearly polarized beams, changing the amplitude ratio and phase difference can change the polarization state of the light wave. Based on the above considerations, this invention proposes a design and fabrication method for a polarization-tunable plastic-encapsulated semiconductor laser. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a plastic-encapsulated semiconductor laser with tunable polarization state. Multiple devices are interconnected on a single lead frame. The laser beam is emitted from the laser and incident perpendicularly onto a polarizer. The polarizer modulates the incident light into linearly polarized light. The modulated linearly polarized light is then incident onto a half-wave plate, causing its polarization direction to deflect. The light exiting the half-wave plate is then incident onto a quarter-wave plate. When the polarization direction of the quarter-wave plate aligns with that of the incident linearly polarized light, the exiting light is linearly polarized, and the half-wave plate can be used to adjust the polarization direction. When the fast axis direction does not align with the polarization direction, the exiting light is elliptically or circularly polarized, and the quarter-wave plate can be used to adjust the ellipticity and rotation. This combination allows for arbitrary polarization state output.

[0005] The present invention also provides a packaging method for the above-mentioned polarization-tunable encapsulated semiconductor laser.

[0006] The technical solution of the present invention is as follows:

[0007] A polarization-tunable plastic-encapsulated semiconductor laser includes a lead frame, a laser chip, a transition heat sink, gold wires, a polarizer, a half-wave plate, and a quarter-wave plate. The lead frame includes a substrate, a plastic-encapsulated frame, leads, and bonding electrodes. The substrate and bonding electrodes are respectively connected to the leads. A slot is provided at the upper end of the substrate for placing the polarizer, half-wave plate, and quarter-wave plate. The plastic-encapsulated frame passes through the leads and wraps around the substrate and bonding electrodes. The substrate is arranged with a quarter-wave plate, a half-wave plate, and a polarizer from top to bottom. A transition heat sink is provided on the substrate below the polarizer, and the laser chip is provided on the transition heat sink. The laser chip is connected to the bonding electrodes through gold wires.

[0008] Preferably, the substrate has two rectangular openings at the bottom, and the rectangular openings contain wire bonding electrodes. Three leads are provided on one side of the rectangular openings. The molding frame wraps the substrate and the wire bonding electrodes. The injection molding opening has the same width as the rectangular opening, so that the leads are insulated from the substrate. The molding frame also reinforces the leads.

[0009] Preferably, the laser chip is placed within the area enclosed by the plastic encapsulation frame, and the height of the laser chip is lower than that of the half-wave plate, quarter-wave plate, and polarizer to prevent accidental damage to the laser during production or use.

[0010] Preferably, the half-wave plate, quarter-wave plate, and polarizer include a frame, and each frame is provided with an adjusting rod and a screw, the screw being used to lock the adjusting rod.

[0011] Preferably, circular through holes are provided on both sides of the substrate to grip the laser and prevent it from falling during the gripping process.

[0012] A packaging method for a polarization-tunable plastic-encapsulated semiconductor laser, comprising the following steps:

[0013] (1) Prepare multiple lead frames, arrange the leads in a double-row array, with the substrate openings all facing outwards, and fix the leads between adjacent substrates and the two sides of the lead array with central ribs. Then form the frame through single injection molding, thus forming a whole frame, which serves as the raw material for laser packaging.

[0014] (2) Die bonding: Use an automatic die bonding machine to place the laser chip onto the transition heat sink after indium evaporation;

[0015] (3) Mounting: Use an automatic mounting machine to attach the COS to the substrate of the lead frame with silver paste;

[0016] (4) Wire bonding: Use an automatic wire bonding machine to bond the gold wires to connect the laser chip and the wire bonding electrodes, forming a wire bonding semi-finished product that exists as a whole piece.

[0017] (5) Cutting the ribs: Cut the ribs on the leads connected to the substrate to form a semi-finished product after cutting the ribs, so that each laser's positive electrode can be energized independently, the negative electrode is the common electrode, the positive electrode is the electrode where the leads connected to the substrate are located, and the negative electrode is the electrode where the bonding wire electrode is located.

[0018] (6) Test: Use a slide rail to move the product after the rib is cut. Set one integrating ball on each side of the end of the slide rail. Use probes to contact the independent positive pole and common negative pole of the laser respectively. After the test is completed, cut the middle rib on the wire bonding electrode connection lead.

[0019] (7) Aging: After aging at room temperature for 3 hours in an aging cabinet, defective products are removed to obtain semi-finished lasers.

[0020] (8) Loading: Using an automatic loading machine, the polarizer, half-wave plate and quarter-wave plate are placed sequentially from the inside to the outside at the opening at the top of the lead frame substrate. After calibration, the finished laser is obtained.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. This invention enables the interconnection of multiple devices on a single lead frame, allowing for arbitrary polarization output. Furthermore, adjustment rods and screws are provided on the frames of the 1 / 2 wave plate, 1 / 4 wave plate, and polarizer, which helps to improve adjustment efficiency.

[0023] 2. The laser chip of this invention is placed within the area surrounded by a waveplate, a polarizer, and a plastic encapsulation frame to prevent accidental damage to the laser during production or use.

[0024] 3. During the testing process, this invention can test two rows of lasers simultaneously, which helps to improve production efficiency and reduce costs. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the finished laser structure of the present invention;

[0026] Figure 2a This is a front view of the lead frame of the present invention;

[0027] Figure 2b This is a side view of the lead frame of the present invention;

[0028] Figure 2c This is a rear view of the lead frame of the present invention;

[0029] Figure 3 This is a schematic diagram of the substrate structure of the present invention;

[0030] Figure 4a This is a schematic front view of the entire frame of the present invention;

[0031] Figure 4bThis is a rear view schematic diagram of the entire frame of the present invention;

[0032] The components are: 1. Lead frame; 2. Laser chip; 3. Gold wire; 4. Lead; 5. Molded frame; 6. Substrate; 7. Bonding electrode; 8. Circular through hole; 9. Transition heat sink; 10. Polarizer; 11. Center rib; 12. Full frame; 13. Half-wave plate; 14. Quarter-wave plate; 15. Slot; 16. Frame; 17. Adjusting rod; 18. Screw; 19. Lead electrode. Detailed Implementation

[0033] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto.

[0034] Example 1:

[0035] like Figure 1-3 As shown, this embodiment provides a polarization-tunable encapsulated semiconductor laser, including a lead frame 1, a laser chip 2, a transition heat sink 9, gold wires 3, a polarizer 10, a half-wave plate 13, and a quarter-wave plate 14. The lead frame 1 includes a substrate 6, an encapsulation frame 5, leads 4, and bonding electrodes 7. The substrate 6 and bonding electrodes 7 are respectively connected to the leads 4. A slot 15 is provided at the upper end of the substrate to accommodate the polarizer 10, the half-wave plate 13, and the quarter-wave plate 14. The encapsulation frame 5 passes through the leads 4 and wraps around the substrate 6 and the bonding electrodes 7. The substrate 6 is provided with the quarter-wave plate 14, the half-wave plate 13, and the polarizer 10 from top to bottom. A transition heat sink 9 is provided on the substrate below the polarizer, and the laser chip 2 is provided on the transition heat sink 9. The laser chip 2 is connected to the bonding electrodes 7 through the gold wires 3.

[0036] The substrate 6 has two rectangular openings at its lower end. The rectangular openings contain wire bonding electrodes. Three leads 4 are provided on one side of each rectangular opening. The molding frame 5 encapsulates the substrate 6 and the wire bonding electrodes 7. The injection molding opening has the same width as the rectangular opening, which insulates the leads 4 from the substrate 6. The molding frame 5 also reinforces the leads.

[0037] The laser chip 2 is placed within the area surrounded by the half-wave plate 13, the quarter-wave plate 14, the polarizer 10, and the plastic encapsulation frame 5, and its height is all below the height of these components to prevent accidental damage to the laser during production or use.

[0038] The frames 16 of the half-wave plate 13, the quarter-wave plate 14 and the polarizer 10 are all equipped with adjusting rods 17 and screws 18. The screws 18 are used to lock the adjusting rods 17 to adjust the position.

[0039] Example 2:

[0040] A polarization-tunable encapsulated semiconductor laser has the structure described in Example 1, except that circular through holes 8 are provided on both sides of the substrate 6 to grip the laser and prevent it from falling during gripping.

[0041] Example 3:

[0042] A packaging method for a plastic-encapsulated semiconductor laser with tunable polarization state as described in Example 2 includes the following steps:

[0043] (1) Arrange the leads in a double-row array, with all substrate openings facing outwards, such as... Figure 4a , Figure 4b As shown, the lead wires are arranged facing inwards, and the leads of adjacent substrates and the two sides of the lead wire array are fixedly connected by the central rib 11. Then, a plastic encapsulation frame is formed by single injection molding, thus forming a whole frame 12, which serves as the raw material for laser packaging.

[0044] (2) Die bonding: Use an automatic die bonding machine to place the laser chip 2 onto the indium-evaporated transition heat sink 9;

[0045] (3) Mounting: Use an automatic mounting machine to attach the COS to the lead frame 1 with silver glue;

[0046] (4) Wire bonding: Use an automatic wire bonding machine to bond the gold wire 3 to connect the laser chip 2 and the wire bonding electrode 7, forming a wire bonding semi-finished product in the form of a whole piece.

[0047] (5) Cutting the ribs: Cut the ribs on the leads connected to the substrate to form a semi-finished product after cutting the ribs, so that each laser positive electrode (i.e., the electrode 19 where the leads connected to the substrate are located) can be energized independently, and the negative electrode (i.e., the electrode where the bonding electrode 7 is located) is the common electrode.

[0048] (6) Test: Use a slide rail to move the product after cutting the reinforcing bar. An integrating ball is set at the end of the slide rail. Use probes to contact the independent positive pole and common negative pole of the laser respectively. After the test is completed, cut the middle reinforcing bar on the wire bonding electrode connection lead.

[0049] (7) Aging: After aging at room temperature for 3 hours in an aging cabinet, defective products are removed to obtain semi-finished lasers.

[0050] (8) Loading: Using an automatic loading machine, the polarizer 10, half-wave plate 13 and quarter-wave plate 14 are placed sequentially from the inside to the outside at the opening of the lead frame substrate. After calibration, the finished laser is obtained.

Claims

1. A polarization state tunable plastic encapsulated semiconductor laser, characterized by, The system includes a lead frame, a laser chip, a transition heat sink, gold wires, a polarizer, a half-wave plate, and a quarter-wave plate. The lead frame comprises a substrate, a molding compound, leads, and bonding electrodes. Leads are connected to the substrate and bonding electrodes. A slot is provided at the top of the substrate to accommodate the polarizer, half-wave plate, and quarter-wave plate. The molding compound passes through the leads and wraps around the substrate and bonding electrodes. The substrate, from top to bottom, contains the quarter-wave plate, half-wave plate, and polarizer. A transition heat sink is located on the substrate below the polarizer, and the laser chip is mounted on the transition heat sink. The laser chip is connected to the bonding electrodes via gold wires. The half-wave plate, quarter-wave plate, and polarizer each include a frame. Each frame has an adjustment rod and a screw for locking the adjustment rod. The laser chip is placed within the area enclosed by the molding compound, and the height of the laser chip is lower than that of the half-wave plate, quarter-wave plate, and polarizer.

2. The polarization-tunable, plastic-packaged semiconductor laser of claim 1, wherein, The substrate has two rectangular openings at the bottom, with wire bonding electrodes inside the rectangular openings. Three leads are provided on one side of each rectangular opening. The molding frame encapsulates the substrate and the wire bonding electrodes. The injection molding opening has the same width as the rectangular opening.

3. The polarization-tunable encapsulated semiconductor laser according to claim 1, characterized in that, Circular through holes are provided on both sides of the substrate.

4. A packaging method for a plastic-encapsulated semiconductor laser with tunable polarization state as described in any one of claims 1-3, characterized in that, The steps are as follows: (1) Prepare multiple lead frames, arrange the leads in a double-row array, with the substrate openings all facing outwards, and connect the leads between adjacent substrates and the two sides of the lead array through a central rib. Then, form the frame through a single injection molding process, thus forming a complete frame, which serves as the raw material for laser packaging. (2) Die bonding: Use an automatic die bonding machine to place the laser chip onto the transition heat sink after indium evaporation; (3) Mounting: Use an automatic mounting machine to attach the COS to the substrate of the lead frame with silver paste; (4) Wire bonding: Use an automatic wire bonding machine to bond the gold wires to connect the laser chip and the wire bonding electrodes, forming a wire bonding semi-finished product in the form of a whole piece; (5) Cutting the ribs: Cut the ribs on the leads connected to the substrate to form a semi-finished product after cutting the ribs, so that each laser positive electrode can be energized independently, the negative electrode is the common electrode, the positive electrode is the electrode where the leads connected to the substrate are located, and the negative electrode is the electrode where the bonding wire electrode is located. (6) Test: Use a slide rail to move the product after the ribs are cut. Set one integrating ball on each side of the end of the slide rail. Use probes to contact the independent positive pole and common negative pole of the laser respectively. After the test is completed, cut the middle rib on the wire bonding electrode connection lead. (7) Aging: After aging at room temperature for 3 hours in an aging cabinet, defective products are removed to obtain semi-finished lasers. (8) Loading: Using an automatic loading machine, the polarizer, half-wave plate and quarter-wave plate are placed sequentially from the inside to the outside at the opening at the top of the lead frame substrate. After calibration, the finished laser is obtained.

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