Integrated tube cap with protruding lens

Abstract

This utility model belongs to the field of optical component technology, specifically relating to an integrated cap with a protruding lens. It includes a metal cap substrate, an optical lens, and glass solder. The metal cap substrate has a central through-hole at its top. The optical lens is integrally sealed to the metal cap substrate by the glass solder. The central through-hole is a stepped through-hole, composed of a large upper hole and a small lower hole arranged coaxially. The optical lens includes an upper optical protrusion and a lower positioning step. The diameter of the positioning step matches the inner diameter of the large upper hole. The positioning step is embedded in the large upper hole, and its lower end face fits against the step surface of the stepped through-hole. The glass solder fills the space between the inner wall of the large upper hole and the side wall of the positioning step, with the upper part of the glass solder extending to the outer periphery of the root of the optical protrusion. This device can improve the positioning accuracy and assembly stability of the lens, while enhancing sealing reliability and environmental adaptability.

Description

Technical Field

[0001] This utility model belongs to the field of optical element technology, specifically relating to an integrated tube cap with a protruding lens. Background Technology

[0002] With the rapid development of 5G communication, laser ranging, automotive LiDAR, and industrial automation technologies, the market demand for high-performance optoelectronic devices is experiencing explosive growth. TO packaging, as one of the most mainstream packaging forms for optoelectronic devices, offers advantages such as small size, low cost, and good compatibility. The TO cap is the core component of TO packaging, undertaking two crucial functions: first, providing long-term reliable hermetic protection for the internal optoelectronic chip, preventing moisture, dust, and harmful gases from intruding and causing chip failure; second, serving as an optical interface to achieve efficient coupling and transmission of optical signals. Therefore, the structural design, sealing reliability, and optical performance of the TO cap directly determine the overall performance, lifespan, and application scenarios of the optoelectronic device. Existing TO caps are mainly divided into two categories: flat-window caps and lens-equipped caps. Flat-window caps use flat optical glass as the window, offering a simple structure and low cost, but they inherently suffer from extremely low optical coupling efficiency. This typically requires the addition of a collimating or focusing lens outside the cap, leading to an increase in the overall size of the optical module, increased assembly complexity, and higher costs. To address the coupling efficiency issue of flat window caps, the industry has developed integrated TO caps with lenses, which directly integrate optical lenses onto the metal cap, eliminating the need for external lens assembly.

[0003] Chinese patent CN112925071A discloses a TO cap for optoelectronic devices and its manufacturing method. It employs a complete spherical glass lens, which is clamped to the upper edge of the through-hole by an interference fit where the spherical diameter is larger than the diameter of the central through-hole in the tube shell, and then sealed with glass solder. While this solution improves coupling efficiency to some extent, it still suffers from the following inherent defects in actual production and application. First, positioning reliability is poor. The spherical lens and the metal tube shell are only supported and positioned through the annular contact between the spherical surface and the orifice, lacking any rigid constraints on axial, radial, and rotational degrees of freedom. The lens is prone to tilting, displacement, and rotation, severely affecting the optical path alignment accuracy. Furthermore, during the soldering process, when the solder melts, the spherical lens may sink and shift due to gravity or gas flow in the furnace, leading to optical path inaccuracy and a significant reduction in yield. Second, sealing performance is insufficient. The solder only fills the triangular gap between the spherical lens and the outer surface of the housing, resulting in an extremely narrow annular contact band and a small sealing area. Furthermore, all stress is concentrated at the contact line, leading to extremely weak impact resistance and making it unsuitable for applications in environments with severe vibrations or harsh conditions. Thirdly, there are limitations to its optical performance. A perfectly spherical lens possesses inherent spherical aberration that cannot be eliminated, resulting in poor beam quality. This makes it unsuitable for the transmission requirements of high-speed optical modules above 10G and also for long-distance optical systems, severely restricting its application scenarios. Utility Model Content

[0004] The purpose of this invention is to provide an integrated tube cap with a protruding lens, which can effectively improve the positioning accuracy and assembly stability of the lens, while enhancing the sealing reliability and environmental adaptability.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows:

[0006] An integrated cap with a protruding lens includes a metal cap substrate, an optical lens, and glass solder. The metal cap substrate has a central through hole at its top. The optical lens is integrally sealed to the metal cap substrate by the glass solder. The central through hole is a stepped through hole, consisting of an upper large hole and a lower small hole arranged coaxially. The optical lens includes an upper optical protrusion and a lower positioning step. The diameter of the positioning step matches the inner diameter of the upper large hole. The positioning step is embedded in the upper large hole, and the lower end face of the positioning step fits against the step surface of the stepped through hole. The glass solder fills the space between the inner wall of the upper large hole and the side wall of the positioning step. The upper part of the glass solder extends to the outer periphery of the root of the optical protrusion, forming a continuous annular sealing structure.

[0007] Furthermore, the optical protrusion has a hemispherical structure, and the optical protrusion and the positioning step are integrally formed.

[0008] Furthermore, the bottom of the metal cap base is provided with an outwardly horizontally extending annular sealing protrusion.

[0009] Furthermore, the lower surface of the annular sealing protrusion is provided with an annular groove for positioning with the TO tube seat.

[0010] Furthermore, the lower section of the stepped through hole is a light-transmitting hole, and the diameter of the lower section of the small hole is smaller than the diameter of the positioning step.

[0011] Furthermore, the sidewall of the positioning step and the inner wall of the upper large hole are in a radial clearance fit.

[0012] Furthermore, the optical protrusion extends completely beyond the outer surface of the metal cap substrate.

[0013] Furthermore, the optical lens is made of borosilicate optical glass.

[0014] Furthermore, the metal cap substrate is made of Kovar alloy.

[0015] The beneficial effects of this utility model are as follows:

[0016] This invention solves the problem of poor lens positioning reliability in the prior art by designing the central through hole as a stepped through hole composed of a large upper hole and a small lower hole arranged coaxially. This through hole cooperates with the positioning step at the bottom of the optical lens, allowing the positioning step to be embedded in the large upper hole. This enables highly stable optical path alignment. The glass solder fills the space between the inner wall of the large upper hole and the side wall of the positioning step, and extends to the outer periphery of the root of the optical protrusion, forming a double sealing structure that combines the main sealing and the reinforced sealing. The optical protrusion protrudes completely from the outer surface of the metal cap substrate, effectively improving the beam focusing accuracy and beam quality, and significantly reducing optical transmission loss. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the structure of this utility model with the optical lens and glass solder removed;

[0019] Figure 3 This is a partial structural diagram of the present invention with the annular sealing protrusion and annular groove removed;

[0020] Figure 4 for Figure 3 Enlarged view of point A in the middle;

[0021] Figure 5 This is a partial structural diagram of the metal cap base, the annular sealing protrusion, and the annular groove in this utility model;

[0022] In the picture:

[0023] 1. Metal cap base; 2. Optical lens; 201. Optical protrusion; 202. Positioning step; 3. Glass solder; 4. Annular sealing protrusion; 5. Annular groove; 6. Central through hole; 601. Upper section large hole; 602. Lower section small hole. Detailed Implementation

[0024] The present invention will now be described and illustrated in detail with reference to the embodiments.

[0025] Example 1

[0026] like Figure 1-5As shown, the integrated cap with a protruding lens includes a metal cap base 1, an optical lens 2, and glass solder 3. The top of the metal cap base 1 has a central through hole 6. The optical lens 2 is sealed to the metal cap base 1 by the glass solder 3. The central through hole 6 is a stepped through hole, which consists of an upper large hole 601 and a lower small hole 602 arranged coaxially. The optical lens 2 includes an upper optical protrusion 201 and a lower positioning step 202. The diameter of the positioning step 202 is adapted to the inner diameter of the upper large hole 601. The positioning step 202 is embedded in the upper large hole 601, and the lower end face of the positioning step 202 is in contact with the step surface of the stepped through hole. The glass solder 3 fills the space between the inner wall of the upper large hole 601 and the side wall of the positioning step 202. The upper part of the glass solder 3 extends to the outer periphery of the root of the optical protrusion 201, forming a continuous annular sealing structure.

[0027] The optical protrusion 201 has a hemispherical structure, and the optical protrusion 201 and the positioning step 202 are integrally formed. The integral formation of the optical protrusion 201 and the positioning step 202 avoids the assembly errors of the split lens, and improves the optical path alignment accuracy and the overall structural stability.

[0028] The bottom of the metal cap base 1 is provided with an outwardly extending horizontally annular sealing protrusion 4. The annular sealing protrusion 4 increases the welding contact area between the cap and the TO pipe seat, ensuring the connection strength between the cap and the TO pipe seat.

[0029] The lower surface of the annular sealing protrusion 4 is provided with an annular groove 5 for positioning with the TO tube seat. The annular groove 5 can form a precise fitting and positioning with the corresponding protrusion on the TO tube seat, preventing displacement during the welding process of the tube cap and the tube seat, and further improving the coaxiality of the overall package.

[0030] The lower section of the stepped through hole, 602, is a light-transmitting hole, and the diameter of the lower section of the small hole 602 is smaller than the diameter of the positioning step 202.

[0031] The sidewall of the positioning step 202 and the inner wall of the upper large hole 601 are in radial clearance fit.

[0032] The optical protrusion 201 protrudes completely from the outer surface of the metal cap substrate 1.

[0033] Optical lens 2 is made of borosilicate optical glass.

[0034] The metal cap substrate 1 is made of Kovar alloy.

[0035] Made of borosilicate optical glass, it features high light transmittance, good chemical stability, and low coefficient of thermal expansion. Furthermore, the coefficient of thermal expansion of the borosilicate optical glass matches that of the glass solder 3 and Kovar alloy. During the sealing and cooling process, the metal cap substrate 1, optical lens 2, and glass solder 3 contract synchronously, which can effectively prevent cracking at the sealing joint due to uneven thermal stress and improve sealing reliability.

[0036] Working principle and process:

[0037] I. Assembly and Sealing

[0038] Align the positioning step 202 of the optical lens 2 with the upper section of the large hole 601 of the metal cap base 1 and embed it vertically, so that the lower end face of the positioning step 202 is completely in contact with the step surface of the central through hole 6, thereby achieving the positioning of the optical lens 2 and ensuring its coaxiality with the central through hole 6.

[0039] Glass solder 3 is filled into the annular gap between the inner wall of the upper large hole 601 and the side wall of the positioning step 202. After high-temperature sintering, the glass solder 3 melts and fully wets the mating surface. Its upper part naturally extends to the outer periphery of the root of the optical protrusion 201. After cooling, it forms a 360° continuous annular sealing structure, permanently sealing the optical lens 2 and the metal cap substrate 1 into one piece.

[0040] Align the sealed cap with the TO tube seat via the bottom annular sealing protrusion 4, and use the annular groove 5 on the lower surface of the annular sealing protrusion 4 to fit and position it with the corresponding protrusion on the TO tube seat. Then, weld the annular sealing protrusion 4 to the TO tube seat by laser welding or soldering to complete the overall encapsulation.

[0041] II. Optical Transmission and Protection

[0042] The optical signal emitted by the optoelectronic device chip on the TO socket first enters the bottom plane of the optical lens 2 through the small hole 602 at the bottom of the metal cap substrate 1. After being refracted inside the optical lens 2, it is focused by the upper hemispherical optical protrusion 201 and then emitted into the external optical fiber or optical system. Since the optical protrusion 201 protrudes completely from the outer surface of the metal cap substrate 1, the optical distance with the internal chip is shortened, effectively reducing the optical transmission loss.

[0043] The double-ring sealing structure formed between the metal cap substrate 1 and the optical lens 2 by the glass solder 3, and the welding seal between the metal cap substrate 1 and the TO tube seat together constitute a complete airtight cavity, which isolates external moisture, dust and harmful gases from intrusion, provides a long-term reliable working environment for the internal optoelectronic device chip, and ensures the service life and stability of the device.

Claims

1. An integrated tube cap with a protruding lens, comprising a metal tube cap substrate (1), an optical lens (2), and glass solder (3), wherein the top of the metal tube cap substrate (1) has a central through hole (6), and the optical lens (2) is integrally sealed to the metal tube cap substrate (1) by the glass solder (3), characterized in that, The central through hole (6) is a stepped through hole, which is composed of an upper large hole (601) and a lower small hole (602) arranged coaxially. The optical lens (2) includes an upper optical protrusion (201) and a lower positioning step (202). The diameter of the positioning step (202) is adapted to the inner diameter of the upper large hole (601). The positioning step (202) is embedded in the upper large hole (601), and the lower end face of the positioning step (202) is in contact with the step surface of the stepped through hole. The glass solder (3) is filled between the inner wall of the upper large hole (601) and the side wall of the positioning step (202). The upper part of the glass solder (3) extends to the outer periphery of the root of the optical protrusion (201) to form a continuous annular sealing structure.

2. The integrated tube cap with a protruding lens according to claim 1, characterized in that, The optical protrusion (201) is a hemispherical structure, and the optical protrusion (201) and the positioning step (202) are integrally formed.

3. The integrated tube cap with a protruding lens according to claim 1, characterized in that, The bottom of the metal cap base (1) is provided with an outwardly horizontally extending annular sealing protrusion (4).

4. The integrated tube cap with a protruding lens according to claim 3, characterized in that, The lower surface of the annular sealing protrusion (4) is provided with an annular groove (5) for positioning with the TO tube seat.

5. The integrated tube cap with a protruding lens according to claim 1, characterized in that, The lower section of the stepped through hole (602) is a light-transmitting hole, and the diameter of the lower section of the small hole (602) is smaller than the diameter of the positioning step (202).

6. The integrated tube cap with a protruding lens according to claim 1, characterized in that, The sidewall of the positioning step (202) and the inner wall of the upper large hole (601) are in radial clearance fit.

7. The integrated tube cap with a protruding lens according to claim 1, characterized in that, The optical protrusion (201) protrudes completely from the outer surface of the metal cap substrate (1).

8. The integrated tube cap with a protruding lens according to claim 1, characterized in that, The optical lens (2) is made of borosilicate optical glass.

9. The integrated tube cap with a protruding lens according to claim 1, characterized in that, The metal cap substrate (1) is made of Kovar alloy.

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