Laser ignition tube with sealed structure

Abstract

The present invention discloses a sealed laser ignition tube, comprising: an ignition tube housing, a lens assembly, and an O-ring; the lens assembly is mounted on the ignition tube housing and secured by laser welding; the O-ring is disposed in the gap between the lens assembly and the ignition tube housing; the lens assembly comprises a lens holder, a metallized self-focusing lens, and brazing material; the metallized self-focusing lens is brazed within the lens holder, and the lens holder is secured within the ignition tube housing by laser welding; the metallized self-focusing lens comprises an anti-reflection film, a selective reflection film, a metal film, and a self-focusing lens; the self-focusing lens has an anti-reflection film coated on its upper end surface, a selective reflection film coated on its lower end surface, and a metal film evaporated on its cylindrical end surface. The sealed laser ignition tube of the present invention has a simple structure, good sealing performance, and can maintain the structural integrity of the laser ignition tube before and after ignition.

Description

Technical Field

[0001] The invention belongs to the technical field of pyrotechnic devices, and in particular relates to a laser ignition tube with a sealed structure. Background Art

[0002] Laser pyrotechnic systems use optical fibers instead of wires to isolate energetic materials from electrical systems, which can fundamentally solve the safety issues of pyrotechnics caused by electromagnetic interference. It is a new type of high-safety pyrotechnic technology. At present, the sealing structure for non-contact laser coupling in laser pyrotechnic systems mainly uses high-temperature sealing of sealing glass powder to weld the self-focusing lens inside the shell to achieve sealing. This sealing structure is relatively complex, and the sealing temperature is too high. Under this sealing temperature condition, it is necessary to first weld the self-focusing lens to the shell through sealing glass to form a sealing body, and then evaporate the functional film on the end face of the sealing body to achieve the transmission of laser energy. This method has a complex structure and cannot guarantee the film effect, which has become a weak link affecting the reliability of laser pyrotechnics. Summary of the Invention

[0003] The technology of the present invention solves the problem: overcomes the deficiencies of the prior art and provides a laser ignition tube with a sealed structure, which has a simple structure, good sealing performance, and can fully realize the structural integrity of the laser ignition tube before and after ignition.

[0004] In order to solve the above technical problems, the present invention discloses a laser ignition tube with a sealed structure, comprising: an ignition tube housing, a lens assembly and an O-ring;

[0005] The lens assembly is mounted on the squib housing and fixed by laser welding;

[0006] An O-ring is disposed in a positional gap between the lens assembly and the squib housing.

[0007] In the laser ignition tube of the above-mentioned sealed structure, the lens assembly includes: a lens seat, a metallized self-focusing lens and a brazing material;

[0008] The metallized self-focusing lens is soldered in the lens holder by solder;

[0009] The lens holder is fixed in the squib housing by laser welding.

[0010] In the laser ignition tube with the above-mentioned sealed structure,

[0011] The clearance between the lens seat and the ignition tube housing is not greater than 0.05mm;

[0012] The metallized self-focusing lens and the lens seat are matched with each other in a clearance not exceeding 0.05 mm.

[0013] In the laser ignition tube with the above-mentioned sealed structure,

[0014] The axis positioning of the metallized self-focusing lens is achieved through the clearance fit between the lens seat and the ignition tube shell;

[0015] The center positioning of the metallized self-focusing lens is achieved through the clearance fit between the metallized self-focusing lens and the lens seat.

[0016] In the laser ignition tube with the above-mentioned sealed structure,

[0017] The material of the lens holder is 30CrMnSiA;

[0018] The solder is SnPb solder.

[0019] In the laser ignition tube with the above-mentioned sealed structure, a groove is formed on the lens seat; wherein the groove is coaxial with the metallized self-focusing lens and is located at the front end of the metallized self-focusing lens, and the groove is filled with a photosensitive agent.

[0020] In the laser ignition tube with the above-mentioned sealed structure, the diameter of the metallized self-focusing lens is any one of the following sizes: 1.0 mm, 1.8 mm, 2.5 mm and 3.0 mm; wherein, when the diameter of the metallized self-focusing lens is 1.0 mm, the intercept of the metallized self-focusing lens is 0.75P; when the diameter of the metallized self-focusing lens is 1.8 mm, or 2.5 mm, or 3.0 mm, the intercept of the metallized self-focusing lens is 0.25P.

[0021] In the laser ignition tube with the above-mentioned sealed structure, the metallized self-focusing lens includes: an anti-reflection film, a selective reflection film, a metal film and a self-focusing lens; wherein the upper end surface of the self-focusing lens is plated with an anti-reflection film, the lower end surface is plated with a selective reflection film, and the cylindrical end surface is evaporated with a metal film.

[0022] In the laser ignition tube with the above-mentioned sealed structure,

[0023] The reflectivity of the antireflection film to lasers with wavelengths of (980±50)nm and (1310±50)nm is not greater than 0.25%, so as to reduce the loss of the ignition laser with a wavelength of (980±50)nm and the detection laser with a wavelength of (1310±50)nm at the upper end face of the metallized self-focusing lens;

[0024] The reflectivity of the selective reflection film to the laser with a wavelength of (1310±50) nm is not less than 95%, and the transmittance is not less than 99%, so as to reduce the loss of the ignition laser with a wavelength of (980±50) nm at the lower end surface of the metallized self-focusing lens, and at the same time ensure that the detection laser with a wavelength of (1310±50) nm returns along the original optical path at the lower end surface of the metallized self-focusing lens;

[0025] The metal film is an Au film with a thickness less than 1 μm, and is used to achieve compatibility between the metallized self-focusing lens and the solder.

[0026] In the laser ignition tube with the above-mentioned sealed structure, the ignition tube housing is used to connect with the optical fiber ST plug to receive laser energy from the laser system.

[0027] The present invention has the following advantages:

[0028] (1) The present invention discloses a laser ignition tube with a sealed structure, which adopts three sealing methods: O-ring sealing + laser welding sealing + brazing sealing to achieve the sealing of the laser ignition tube structure. This sealing combination method can perfectly achieve the structural integrity of the laser ignition tube before and after ignition, and has good sealing performance, and is suitable for various laser igniters and laser detonators.

[0029] (2) The present invention discloses a laser ignition tube with a sealed structure, which uses a commonly used ST interface for optical fibers. It has a high degree of universality and can be effectively applied to optical fiber connections on the market, and has wide applicability.

[0030] (3) The present invention discloses a laser ignition tube with a sealed structure. A gap is designed between the plug and the end face of the metallized self-focusing lens in the sealed structure. The non-contact design can effectively avoid damage to the contact surface due to friction and collision, thereby improving the reliability of the optical coupling link of the laser ignition tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of a laser ignition tube with a sealed structure according to an embodiment of the present invention;

[0032] Figure 2 is a schematic structural diagram of a lens assembly according to an embodiment of the present invention;

[0033] Figure 3 It is a structural schematic diagram of a metallized self-focusing lens in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0035] like Figure 1 In this embodiment, the sealed laser ignition tube comprises: an ignition tube housing 1, a lens assembly 2, and an O-ring 6. The lens assembly 2 is mounted on the ignition tube housing 1 and secured by laser welding; the O-ring 6 is disposed in the gap between the lens assembly 2 and the ignition tube housing 1.

[0036] In this embodiment, if Figure 2The lens assembly 2 may specifically include: a lens holder 3, a metallized self-focusing lens 4 and a brazing material 5. The metallized self-focusing lens 4 is welded to the lens holder 3 by the brazing material 5; and the lens holder 3 is fixed to the squib housing 1 by laser welding.

[0037] Preferably, the lens holder 3 and the squib housing 1 have a clearance fit of no more than 0.05 mm; the metallized self-focusing lens 4 has a clearance fit of no more than 0.05 mm. The clearance fit between the lens holder 3 and the squib housing 1 allows the axis of the metallized self-focusing lens 4 to be positioned; the clearance fit between the metallized self-focusing lens 4 and the lens holder 3 allows the center of the metallized self-focusing lens 4 to be positioned.

[0038] Preferably, the lens holder 3 may be made of a material with low Cr content, preferably 30CrMnSiA. The solder 5 may be made of a material with a melting point not exceeding 250° C., preferably SnPb solder.

[0039] Preferably, Figure 2 The lens seat 3 is provided with a groove 7. The groove 7 is coaxial with the metallized self-focusing lens 4 and is located at the front end of the metallized self-focusing lens 4. The groove 7 is filled with a photosensitive agent 8.

[0040] Preferably, the diameter of the metallized self-focusing lens 4 is any one of the following sizes: 1.0 mm, 1.8 mm, 2.5 mm, and 3.0 mm. Among them, the intercept of the metallized self-focusing lens 4 with a diameter of 1.0 mm is preferably 0.75P, and the intercept of the metallized self-focusing lens 4 with a diameter of 1.8 mm, 2.5 mm, or 3.0 mm is preferably 0.25P. Under the corresponding intercept conditions, it can be ensured that the length of the metallized self-focusing lens 4 can meet the sealing and positioning requirements.

[0041] In this embodiment, if Figure 3 The metallized self-focusing lens 4 may specifically include: an anti-reflection film 401, a selective reflection film 402, a metal film 403, and a self-focusing lens 404. The self-focusing lens 404 has an anti-reflection film 401 coated on its upper end surface, a selective reflection film 402 coated on its lower end surface, and a metal film 403 evaporated on its cylindrical end surface.

[0042] Preferably, the antireflection film 401 has a reflectivity of no more than 0.25% for lasers with wavelengths of (980±50) nm and (1310±50) nm, thereby reducing the energy loss of the (980±50) nm ignition laser and (1310±50) nm detection laser at the upper end face of the metallized self-focusing lens 4. The selective reflection film 402 has a reflectivity of no less than 95% and a transmittance of no less than 99% for lasers with a wavelength of (1310±50) nm, thereby reducing the energy loss of the (980±50) nm ignition laser at the lower end face of the metallized self-focusing lens 4 and ensuring that the (1310±50) nm detection laser returns along the original optical path at the lower end face of the metallized self-focusing lens 4. The metal film 403 is an Au film with a thickness of less than 1 μm, and is used to achieve compatibility between the metallized self-focusing lens 4 and the solder 5.

[0043] In this embodiment, the ignition tube housing 1 is used to connect to the optical fiber ST plug to receive laser energy from the laser system.

[0044] In summary, the present invention discloses a laser ignition tube with a sealed structure, which adopts three sealing methods to achieve the sealing of the structure, namely O-ring sealing + laser welding sealing + brazing sealing. The O-ring sealing adopts a universal O-ring to achieve the sealing between the light input end of the ignition tube and the lens assembly; the laser welding sealing fixes the lens assembly to the ignition tube shell by laser welding to achieve the sealing between the output end of the lens assembly and the ignition tube shell; the brazing sealing brazes the metallized self-focusing lens directly to the lens seat by brazing material to achieve the sealing of the structure. At the same time, the present invention adopts the commonly used ST interface to achieve the universal design of the interface with wide applicability; in addition, the laser energy can be transmitted by non-contact technology, which can effectively prevent the problem of optical fiber end face collision caused by the plug-in and separation process and vibration impact stress, thereby improving the optical coupling reliability of the laser ignition tube.

[0045] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

[0046] The contents not described in detail in the specification of the present invention belong to the common knowledge of professionals in this field.

Claims

1. A laser ignition tube with a sealed structure, characterized in that: include: Squib housing (1), lens assembly (2) and O-ring (6); The lens assembly (2) is mounted on the squib housing (1) and fixed by laser welding; an O-ring (6) is arranged in a position gap between the lens assembly (2) and the squib housing (1); The lens assembly (2) comprises: a lens seat (3), a metallized self-focusing lens (4) and a brazing material (5); wherein the metallized self-focusing lens (4) is welded in the lens seat (3) by the brazing material (5); the metallized self-focusing lens (4) and the lens seat (3) are clearance-matched, the clearance is not greater than 0.05 mm, and the center positioning of the metallized self-focusing lens (4) is achieved by the clearance matching between the metallized self-focusing lens (4) and the lens seat (3); the lens seat (3) is fixed in the ignition tube housing (1) by laser welding; the lens seat (3) and the ignition tube housing (1) are clearance-matched, the clearance is not greater than 0.05 mm, and the axis positioning of the metallized self-focusing lens (4) is achieved by the clearance matching between the lens seat (3) and the ignition tube housing (1); a groove (7) is formed on the lens seat (3); the groove (7) is coaxial with the metallized self-focusing lens (4) and is located at the front end of the metallized self-focusing lens (4); the groove (7) is filled with a photosensitizing agent (8); The metallized self-focusing lens (4) comprises an anti-reflection film (401), a selective reflection film (402), a metal film (403) and a self-focusing lens (404); wherein the upper end surface of the self-focusing lens (404) is plated with the anti-reflection film (401), the lower end surface is plated with the selective reflection film (402), and the cylindrical end surface is evaporated with the metal film (403); the reflectivity of the anti-reflection film (401) to lasers with wavelengths of (980±50)nm and (1310±50)nm is not greater than 0.25%, so as to reduce the reflection of the ignition laser with a wavelength of (980±50)nm and the detection laser with a wavelength of (1310±50)nm. Energy loss at the upper end face of the metallized self-focusing lens (4); the reflectivity of the selective reflection film (402) to the laser with a wavelength of (1310±50) nm is not less than 95%, and the transmittance is not less than 99%, so as to reduce the loss of the ignition laser with a wavelength of (980±50) nm at the lower end face of the metallized self-focusing lens (4), while ensuring that the detection laser with a wavelength of (1310±50) nm returns along the original optical path at the lower end face of the metallized self-focusing lens (4); the metal film (403) is an Au film with a film thickness of less than 1 μm, and is used to achieve compatibility between the metallized self-focusing lens (4) and the solder (5).

2. The laser ignition tube with a sealed structure according to claim 1, characterized in that: The material of the lens holder (3) is 30CrMnSiA; The solder (5) is SnPb solder.

3. The laser ignition tube with a sealed structure according to claim 1, characterized in that: The diameter of the metallized self-focusing lens (4) is any one of the following sizes: 1.0 mm, 1.8 mm, 2.5 mm, and 3.0 mm; wherein, when the diameter of the metallized self-focusing lens (4) is 1.0 mm, the intercept of the metallized self-focusing lens (4) is 0.75P; and when the diameter of the metallized self-focusing lens (4) is 1.8 mm, or 2.5 mm, or 3.0 mm, the intercept of the metallized self-focusing lens (4) is 0.25P.

4. The laser ignition tube with a sealed structure according to claim 1, characterized in that: The ignition tube housing (1) is used to be connected to the optical fiber ST plug to receive laser energy from the laser system.

Images