Tongue-free coaxial TO laser and packaging method thereof

Abstract

The invention provides a tube tongue-free coaxial TO laser and a packaging method thereof, and relates to the technical field of lasers. The tube tongue-free coaxial TO laser comprises a tube base, a COS structure is arranged on the tube base, and the COS structure comprises a heat sink and a chip arranged on the heat sink. The tube seat is provided with a reflecting mirror, the reflecting mirror comprises a reflecting surface, the reflecting surface of the reflecting mirror directly faces a light emitting point of the chip, and an included angle alpha between the reflecting surface and the tube seat is 45 degrees. When the chip of the COS structure emits light, the incidence point of the light on the reflecting surface is on the axis of the tube socket. According to the tube-tongue-free coaxial TO laser and the packaging method thereof provided by the invention, the overall height of the tube socket can be effectively reduced, and convenience is provided for product miniaturization.

Description

Technical Field

[0001] The invention relates to the technical field of lasers, in particular to a tongue-free coaxial TO laser and a packaging method thereof. Background Art

[0002] Coaxial packaging is the main packaging form of semiconductor lasers in low-power red laser applications. According to the differences in chip structure, the mainstream products include surface-emitting VCSEL and end-emitting EEL. EEL end-emitting lasers are highly mature and widely used in long-distance signal transmission. Although surface-emitting VCSELs have multiple advantages, such as good beam quality, no cavity surface catastrophe, and small temperature drift, their main application is short-distance signal transmission. Due to the maturity of chip technology, many products are prone to form black spots in the center of the light spot in the far field. Therefore, end-emitting EEL is still the mainstream technology for signal transmission applications.

[0003] like Figure 8 As shown in the figure, the current end-emitting EEL technology adopts a tube tongue structure, and then the chip is mounted on the tube tongue, so that the end beam is coaxial with the TO tube socket. According to the current conventional technical parameters, the tube tongue height is generally 1.49mm. In order to protect the laser structure, conventional technology requires encapsulation of a tube cap with a glass window. Therefore, the overall height of the tube socket is generally greater than 2.7mm, which directly affects the thickness of the downstream complete product. Summary of the invention

[0004] In view of the above problems, the present application provides a tongue-free coaxial TO laser and a packaging method thereof, which can effectively reduce the overall height of the tube holder.

[0005] The technical solution adopted by the present invention to solve the technical problem is:

[0006] A tongue-free coaxial TO laser comprises a tube base, a COS structure is arranged on the tube base, and the COS structure comprises a heat sink and a chip arranged on the heat sink;

[0007] A reflector is arranged on the tube holder, the reflector comprises a reflective surface, the reflective surface of the reflector faces the light emitting point of the chip, and the angle α between the reflective surface and the tube holder is 45°;

[0008] When the chip with the COS structure emits light, the incident point of the light on the reflection surface is on the axis of the tube seat.

[0009] Furthermore, the reflective surface of the reflector is optically coated.

[0010] Furthermore, a limiting ring is provided on the outer coaxial sleeve of the tube base, and the upper end surface of the limiting ring is located above the upper side surface of the tube base, and the limiting ring is filled with LED high-transmittance sealant.

[0011] Furthermore, the limiting ring is made of ABS resin, and the lower end surface of the limiting ring is flush with the bottom surface of the tube seat.

[0012] Furthermore, the LED high light transmittance sealant is epoxy glue.

[0013] Furthermore, the cross section of the reflector is an isosceles right triangle, one right-angled side is a reflective surface, and the other right-angled side is a rough surface.

[0014] Furthermore, the slope length L of the reflecting surface of the reflector is 700umm.

[0015] Furthermore, the distance from the light-emitting point of the chip to the axis of the tube base is 300um.

[0016] A packaging method for a tongue-free coaxial TO laser comprises the following steps:

[0017] S1, install the COS structure on the tube base;

[0018] S2, installing a reflector in the central area of ​​the tube holder, wherein the reflective surface of the reflector is directly opposite to the light-emitting point of the chip, and when the chip of the COS structure emits light, the incident point of the light on the reflective surface is on the axis of the tube holder;

[0019] S3, installing a restriction ring on the outside of the tube seat;

[0020] S4, injecting LED high light transmittance sealant into the confinement ring;

[0021] S5, placing the laser obtained in step S4 into a device for baking, so that the LED high light transmittance sealant injected into the confinement ring is solidified.

[0022] Furthermore, the COS structure and the reflector are assembled using a silver glue die-bonding process.

[0023] The beneficial effects of the present invention are:

[0024] The embodiments of the present application provide a tongue-free coaxial TO laser and a packaging method thereof. By adopting a 45-degree reflector to change the optical path, the end light beam emitted by the COS chip can be coaxial with the axis of the tube holder without the need for a tongue. In addition, since the traditional tongue is removed, the height of the entire tube holder is effectively reduced, which facilitates the miniaturization of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the three-dimensional structure of a tongue-free coaxial TO laser provided in Example 1 of the present application;

[0026] Figure 2 A top view of a tongue-free coaxial TO laser provided in Example 1 of the present application;

[0027] Figure 3 for Figure 2 AA section view in;

[0028] Figure 4 for Figure 3 A schematic diagram of the enlarged structure of part A;

[0029] Figure 5 Schematic diagram of the preparation process of the reflector;

[0030] Figure 6 A schematic diagram of the three-dimensional structure of a tongue-free coaxial TO laser provided in Example 2 of the present application;

[0031] Figure 7 A schematic diagram of the three-dimensional structure of a tongue-free coaxial TO laser provided in Example 3 of the present application;

[0032] Figure 8 This is an exploded view of a traditional tube-tongue structure laser.

[0033] In the figure: 1, tube socket; 11, negative tube leg; 12, axis;

[0034] 21. Heat sink; 22. Chip;

[0035] 3. Welding wire;

[0036] 4. Reflector; 41. Reflecting surface; 42. Rough surface; 43. Inclined surface;

[0037] 5. Restriction ring. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described in detail below in conjunction with the drawings in the embodiments of the present application, and the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by those skilled in the art without creative work on the basis of the embodiments of the present application shall belong to the protection scope of the present application.

[0039] Embodiment 1

[0040] like Figure 1 , Figure 2 and Figure 3As shown, a tongue-free coaxial TO laser includes a tube base 1, on which a COS structure is arranged. The COS structure includes a heat sink 21 and a chip 22 arranged on the heat sink 21. The chip 22 is connected to the negative tube leg 11 of the tube base 1 through a welding wire 3.

[0041] A reflector 4 is disposed in the middle of the tube seat 1, and the reflector 4 includes a reflective surface 41, which is a smooth surface of the crystal axis. The reflective surface 41 of the reflector 4 faces the light emitting point of the chip 22, and the angle α between the reflective surface 41 and the tube seat 1 is 45°.

[0042] like Figure 4 As shown, when the COS structure chip 22 emits light, the incident point A of the light on the reflection surface 41 is on the axis 12 of the tube seat 1. This ensures that the reflected light spot is perpendicular to the tube seat 1 and coaxial with the tube seat 1.

[0043] As a specific implementation, in this embodiment, the slope length L of the reflection surface 41 of the reflector 4 is 700um, and the distance from the light emitting point of the chip 22 to the axis 12 of the stem 1 is 300um.

[0044] Furthermore, the reflective surface 41 of the reflector 4 is optically coated, and the film system is a high-reflective film system corresponding to the laser wavelength.

[0045] Furthermore, the reflector 4 is processed by wire cutting, and the cross section of the reflector 4 is an isosceles right triangle, one right-angled side of which is a reflective surface 41, and the other right-angled side is a rough surface 42, and the rough surface 42 is perpendicular to the crystal axis direction.

[0046] As a specific implementation, this embodiment provides a method for preparing a reflector 4. Figure 5 As shown, the silicon crystal is first cut along the crystal axis direction (solid line direction) and the direction perpendicular to the crystal axis (dashed line direction) and cut into 700um square semi-finished products, and then the semi-finished products are fixed on the substrate plate and cut diagonally at a 45 degree angle by wire cutting. The surface cut along the crystal axis direction forms the reflecting surface 41 of the reflector 4.

[0047] Furthermore, if Figure 1 and Figure 3 As shown, the outer coaxial sleeve of the tube base 1 is provided with a limiting ring 5, and the upper end surface of the limiting ring 5 is located above the upper side surface of the tube base 1. The limiting ring 5 is filled with LED high light transmittance sealant (not shown in the figure), and the upper end surface of the LED high light transmittance sealant is flush with the upper end surface of the limiting ring 5.

[0048] As a specific implementation manner, the limiting ring 5 described in this embodiment is made of ABS resin, with a thickness of 0.5 mm and a height of 2 mm, and the lower end surface of the limiting ring 5 is flush with the bottom surface of the tube seat 1 .

[0049] As a specific implementation, the restriction ring 5 described in this embodiment is fixedly connected to the tube seat 1 by tensioning.

[0050] As a specific implementation, the LED high-transmittance sealant described in this embodiment adopts epoxy glue with the highest transmittance in the industry of 98%.

[0051] The aperture of conventional glass window caps is generally less than 1mm, and the light beam emitted by the EEL end is slightly blocked in the fast axis direction, which will affect the beam quality and optical power. In addition, in the prior art, window caps are usually made of metal, glass and other materials, which have certain limitations in terms of weather resistance and corrosion resistance. When metal caps are exposed to outdoor environments for a long time, the seal will fail due to corrosion. Since LED high-light-transmittance sealants have many advantages over window caps in terms of air tightness. It can provide excellent sealing performance, good weather resistance, strong adaptability and easy construction. Therefore, this application uses LED high-light-transmittance sealants for packaging, which can not only effectively ensure air tightness, avoid damage to metal caps in high-humidity and high-corrosion environments, and is easy to implement, but also can avoid the problem of light beams being blocked in the fast axis direction. In addition, since the use of LED high-light-transmittance sealants for packaging does not require a nitrogen atmosphere, the window cap packaging method has advantages in heat dissipation and stability compared to the traditional nitrogen atmosphere.

[0052] A method for packaging a tongue-free coaxial TO laser comprises the following steps:

[0053] S1, using the existing technical equipment in the industry, the COS structure is installed on the tube holder 1, and the distance from the light-emitting point of the chip 22 of the COS structure to the center of the tube holder 1 is 300um.

[0054] S2, install the reflector 4 in the central area of ​​the tube holder 1, the reflective surface 41 of the reflector 4 is opposite to the light-emitting point of the chip 22, and the light-emitting point of the COS chip 22 presented by the reflective surface 41 of the reflector 4 is located in the center of the tube holder 1, ensuring that the reflected light spot is perpendicular to the tube holder 1 and coaxial with the tube holder 1.

[0055] S3, installing the limiting ring 5 on the outside of the tube base 1.

[0056] S4, injecting LED high light transmittance sealant into the limiting ring 5 until the liquid level of the LED high light transmittance sealant is flush with the upper edge of the limiting ring 5.

[0057] S5, placing the laser obtained in step S4 into the equipment for baking, so that the LED high light transmittance sealant injected into the confinement ring 5 is solidified.

[0058] As a specific implementation, the assembly of the COS structure and the reflector 4 described in this embodiment adopts a silver glue die-bonding process. During installation, the positions of the COS structure and the reflector 4 are first adjusted, and then baked and cured after adjusting to the appropriate positions.

[0059] Embodiment 2

[0060] like Figure 6 As shown, the cross section of the reflector 4 is a parallelogram structure. The rest of the structure is the same as that of the first embodiment.

[0061] Embodiment 3

[0062] like Figure 7 As shown, the cross section of the reflector 4 is an isosceles trapezoidal structure. The rest of the structure is the same as that of the first embodiment.

[0063] Embodiment 4

[0064] A tongue-free coaxial TO laser structure is as described in the first embodiment, except that it is not packaged by glue filling, but by a low-height window cap. The packaging method of the window cap is prior art and will not be described in detail here.

[0065] Other embodiments obtained by those skilled in the art by combining, splitting, reorganizing, etc. the embodiments of the present application on the basis of the embodiments provided in the present application do not exceed the protection scope of the present application.

[0066] The above specific implementation methods have detailed the purpose, technical solutions and beneficial effects of the embodiments of the present application. The above are only specific implementation methods of the embodiments of the present application and are not used to limit the protection scope of the embodiments of the present application. That is, any modifications, equivalent substitutions, improvements, etc. made on the basis of the embodiments of the present application should be included in the protection scope of the embodiments of the present application.

Claims

1. A tongue-free coaxial TO laser, characterized in that: It comprises a tube base (1), the tube base (1) being provided with a COS structure, the COS structure comprising a heat sink (21) and a chip (22) arranged on the heat sink (21); A reflector (4) is arranged on the tube seat (1), the reflector (4) comprises a reflective surface (41), the reflective surface (41) of the reflector (4) faces the light exit point of the chip (22), and an angle α between the reflective surface (41) and the tube seat (1) is 45°; When the chip (22) with a COS structure emits light, the incident point of the light on the reflection surface (41) is on the axis (12) of the tube seat (1).

2. The tongue-free coaxial TO laser according to claim 1, characterized in that: The reflective surface (41) of the reflector (4) is optically coated.

3. The tongue-free coaxial TO laser according to claim 1, characterized in that: A limiting ring (5) is provided on the outer coaxial sleeve of the tube base (1), and the upper end surface of the limiting ring (5) is located above the upper side surface of the tube base (1), and the limiting ring (5) is filled with LED high-transmittance sealant.

4. The tongue-free coaxial TO laser according to claim 3, characterized in that: The limiting ring (5) is made of ABS resin, and the lower end surface of the limiting ring (5) is flush with the bottom surface of the tube seat (1).

5. The tongue-free coaxial TO laser according to claim 3, characterized in that: The LED high light transmittance sealant is epoxy glue.

6. The tongue-free coaxial TO laser according to claim 1, characterized in that: The cross section of the reflector (4) is an isosceles right triangle, one right-angled side is a reflective surface (41), and the other right-angled side is a rough surface (42).

7. The tongue-free coaxial TO laser according to claim 1, characterized in that: The slope length L of the reflecting surface (41) of the reflecting mirror (4) is 700umm.

8. The tongue-free coaxial TO laser according to claim 1, characterized in that: The distance from the light-emitting point of the chip (22) to the axis (12) of the tube base (1) is 300 um.

9. A packaging method for a tongue-free coaxial TO laser according to claim 3, characterized in that: The following steps are included: S1, installing the COS structure on the tube holder (1); S2, installing a reflector (4) in the central area of ​​the tube holder (1), wherein the reflective surface (41) of the reflector (4) is directly opposite to the light-emitting point of the chip (22), and when the chip (22) with the COS structure emits light, the incident point of the light on the reflective surface (41) is on the axis (12) of the tube holder (1); S3, installing a restriction ring (5) on the outside of the tube seat (1); S4, injecting LED high light transmittance sealant into the confinement ring (5); S5, placing the laser obtained in step S4 into a device for baking, so that the LED high light transmittance sealant injected into the confinement ring (5) is solidified.

10. The packaging method of a tongue-free coaxial TO laser according to claim 9, characterized in that: The COS structure and the reflector (4) are both assembled using a silver glue die-cement process.

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