A method of encapsulating an optical window

Abstract

The application discloses a packaging method of an optical window, comprising the following steps: (1) focusing a laser beam on the upper surface of a metal window seat after the laser beam passes through a transparent optical window sheet, so that the metal window seat absorbs laser energy and is heated and gasified; (2) adjusting the laser energy, so that the laser energy is greater than the breakdown threshold of the metal window seat, at this time, the metal window seat will be broken down, avalanche ionization is generated, and high-temperature and high-pressure plasma is formed; (3) continuously causing local explosion of the plasma based on the laser energy, and forming an upward floating plasma plume, the plasma plume deposits or etches the lower surface of the transparent optical window sheet, leading to transient absorption enhancement of the lower surface material, and the plasma of the lower surface of the transparent optical window sheet forms a molten metal due to temperature reduction; the transparent optical window sheet continues to absorb laser energy to cause thermal ablation, and then forms a chemical metallurgical bond with the surface of the broken-down metal window seat in step (2), and then the welding packaging of the transparent optical window sheet and the metal window seat is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to a packaging process, more particularly to a laser-induced plasma welding packaging process for an optical window. BACKGROUND

[0002] An optical window is a transparent window used in an optical system or device to transmit light and information and prevent the external environment from affecting the interior of the optical system or device. At present, the optical window has been widely used in various industries as a very important device, such as biomedical, microelectronics, aviation and navigation fields. The optical window often needs to work in a harsh environment (high temperature and high pressure), and the packaging quality is directly related to the service life of the device. To ensure that the device containing the optical window can fully function, the packaging reliability of the optical window becomes the primary task, and the selection of a suitable packaging process becomes the most critical and difficult problem in the manufacturing technology of the optical window. The sealing and packaging method of the optical window in the prior art is to use a sealing oil ring, glue joint and brazing packaging method. However, the optical window sealed by pressure is easily deformed under long-term stress, which reduces the sealing effect. Other processing methods of the optical window, such as electroplating of heating wires on the surface of the optical glass or blowing hot air to the surface of the optical glass outside the high and low temperature chamber, operating test under low temperature conditions, heating the surface of the optical glass to prevent frosting, and similar processing methods will cause the shape precision of the surface of the optical glass to not meet the requirements, thereby causing the optical test under low temperature conditions to not be able to proceed normally. SUMMARY

[0003] In view of the above problems, the packaging method of the optical window provided by the present application avoids the situation that the sealing effect deteriorates over time caused by the pressure packaging in the prior art, and also avoids the problem that the precision of the optical window does not meet the requirements under extreme temperature conditions.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a packaging method of an optical window, comprising the following steps:

[0005] (1) focusing a laser beam on the upper surface of a metal window seat after the laser beam passes through a transparent optical window piece, so that the metal window seat absorbs laser energy and heats up and vaporizes;

[0006] (2) adjusting the laser energy so that the laser energy is greater than the breakdown threshold of the metal window seat, at which time the metal window seat will be broken down, avalanche ionization will occur, and a high-temperature, high-pressure plasma will be formed;

[0007] (3) continuously cause local explosion based on the plasma laser energy, and form an upward floating plasma plume, which deposits or etches the lower surface of the transparent optical window piece, resulting in transient absorption enhancement of the lower surface material, and the plasma of the lower surface of the transparent optical window piece forms a molten metal due to temperature reduction;

[0008] (4) the transparent optical window piece continues to absorb laser energy to cause thermal ablation, and further forms a chemical and metallurgical bond with the broken-through metal window seat surface in step (2), thereby achieving welding packaging of the transparent optical window piece and the metal window seat.

[0009] Preferably, the laser is controlled by a computer control system to generate a laser beam that is focused on the upper surface of the metal window seat through the transparent optical window piece and scanned to achieve welding packaging of the transparent optical window piece and the metal window seat.

[0010] Preferably, the contact distance between the transparent optical window piece and the metal window seat in step (4) is less than 1 mm.

[0011] Preferably, the welding packaging strength of the transparent optical window piece and the metal window seat is adjusted by adjusting the line width and spacing of the laser scanning and the laser parameters.

[0012] The present application has the following beneficial effects: the present application changes the existing commonly used optical window gluing and brazing packaging process into a laser-induced plasma welding packaging process, solves the problems of poor packaging quality, low high temperature and high pressure resistance of the optical window, and the like. The packaging process of the present application has good sealing effect, reliable packaging, high temperature and high pressure resistance of the optical window after packaging, simple and ingenious technology, and is easy to implement. It is suitable for the fields of biomedicine, microelectronics, aviation and navigation, etc. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For the first skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0014] Figure 1 is a flowchart of the laser-induced plasma welding packaging process.

[0015] Figure 2 is a welding principle diagram of the laser-induced plasma welding packaging process.

[0016] Figure 3 is a welding strength test (pushing and shearing experiment) diagram of the optical window welding packaging sample.

[0017] Figure 4 is a graph of the results of the weld strength test (push-off experiment) of the laser window weld package samples.

[0018] In the figure: 101 - computer control system; 102 - laser; 103 - laser beam; 104 - transparent optical window sheet; 105 - metal window seat; 201 - high pressure plasma; 202 - plasma plume; 301 - optical window after weld packaging; 302 - V-shaped clamp; 303 - push-off tool head; 304 - computer system of push-off equipment; 401 - weld strength curve of transparent optical window sheet and metal window seat welded by ordinary brazing technology; 402 - weld strength curve of transparent window sheet and metal window seat welded by laser-induced plasma weld packaging process. DETAILED DESCRIPTION

[0019] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work under the premise of fall within the scope of protection of the present application. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work under the premise of fall within the scope of protection of the present application.

[0020] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0021] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited.

[0022] In the present application, unless specifically defined and limited otherwise, the terms "mounting", "connected", "connecting", "fixed", and the like, should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements. For the first skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] In the present application, unless specifically defined and limited otherwise, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0024] Embodiment

[0025] The following is only a preferred embodiment of the present application, and the protection scope of the present application is not limited to the following examples. Any technical solution that belongs to the idea of the present application falls within the protection scope of the present application.

[0026] Reference Description Figures 1-2 A packaging method of an optical window, comprising the following steps:

[0027] (1) Focus the laser beam on the upper surface of the metal window seat after transmitting through the transparent optical window piece, so that the metal window seat absorbs the laser energy and is heated and gasified;

[0028] (2) Adjust the laser energy so that the laser energy is greater than the breakdown threshold of the metal window seat, at which time the metal window seat will be broken down, avalanche ionization will occur, and high-temperature, high-pressure plasma will be formed;

[0029] (3) Continuously cause local explosion of the plasma based on the laser energy, and form an upwardly floating plasma plume, which deposits or etches the lower surface of the transparent optical window piece, resulting in transient absorption enhancement of the lower surface material, and the plasma of the lower surface of the transparent optical window piece forms a molten metal due to temperature reduction;

[0030] (4) The transparent optical window continues to absorb laser energy to cause thermal ablation, and then forms a chemical metallurgical bond with the surface of the broken-down metal window seat in step (2), thereby achieving the welding packaging of the transparent optical window and the metal window seat. The contact distance between the transparent optical window and the metal window seat in step (4) is less than 1 mm.

[0031] Referring to the accompanying drawings Figure 1 In the laser-induced plasma welding packaging process of the present application, the computer control system 101 controls the laser 102 to generate a laser beam 103 through signal transmission, the laser beam 103 is focused on the upper surface of the metal window seat 105 through the transparent optical window 104 and is scanned, thereby achieving the welding packaging of the transparent optical window 104 and the metal window seat 105. Referring to the accompanying drawings Figure 2 The laser beam 103 is focused on the upper surface of the metal window seat 105 through the transparent optical window 104, and the metal window seat 105 absorbs laser energy to heat and vaporize. When the laser energy is greater than the breakdown threshold of the metal window seat 105, the metal window seat 105 will be broken down, avalanche ionization will occur, and a high-temperature, high-pressure plasma 201 will be formed. The plasma 201 continues to absorb laser energy to cause local explosion, forming an upwardly floating plasma plume 202, depositing or etching the lower surface of the transparent optical window 104, causing transient absorption enhancement of the lower surface material, and the deposited plasma 201 forms a molten metal due to temperature reduction. The modified transparent optical window 104 continues to absorb laser energy to cause thermal ablation of the transparent optical window 104, and then forms a chemical metallurgical bond with the high-surface-activity molten metal window seat 105 surface, thereby achieving the welding packaging of the transparent optical window 104 and the metal window seat 105.

[0032] Referring to the accompanying drawings Figure 3 The welded and packaged optical window 301 is fixed on the shearing equipment through a V-shaped clamp 302, the V-shaped clamp 302 only acts on the metal window seat 105 and does not generate any force on the transparent optical window 104. The transparent optical window 104 is located directly below the push shear cutter head 303, and the right side surface of the transparent optical window 104 is ensured to be in the same vertical plane as the right side surface of the push shear cutter head 303. The computer system 304 of the push shear equipment controls the push shear cutter head 303 to move vertically downward to act on the upper side surface of the transparent optical window 104 until the transparent optical window 104 is separated from the metal window seat 105, and the relationship between the stroke of the push shear cutter head and the size of the applied load force is recorded.

[0033] Referring to the accompanying drawings Figure 4The abscissa of the welding strength test result is stroke / mm, and the ordinate is load / N. The welding strength curve 401 of the transparent light window piece and the metal window seat welded by using the ordinary brazing technology and the welding strength curve 402 of the transparent window piece and the metal window seat welded by using the laser-induced plasma welding packaging process are shown. By observing and comparing the welding strength curves of the two welding methods, it can be seen that the welding strength of the transparent light window piece and the metal window seat welded by using the laser-induced plasma welding packaging process is higher, and the welding effect is better. By adjusting the line width and interval of scanning and the laser parameters, the welding strength can be further improved and optimized.

[0034] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A method of encapsulating an optical window, characterized by, Comprising the following steps: (4) Focus the laser beam through the transparent optical window piece on the upper surface of the metal window seat, so that the metal window seat absorbs laser energy and warms up and gasifies; (5) Adjust the laser energy so that the laser energy is greater than the breakdown threshold of the metal window seat, at which time the metal window seat will be broken down, avalanche ionization will be generated, and high-temperature, high-pressure plasma will be formed; (6) Continue to cause local explosion of the plasma based on the laser energy, and form an upwardly floating plasma plume, which deposits or etches the lower surface of the transparent optical window piece, causing transient absorption enhancement of the lower surface material, and the plasma of the lower surface of the transparent optical window piece forms a molten metal due to temperature reduction; (7) The transparent optical window piece continues to absorb laser energy to cause thermal ablation, and then forms a chemical and metallurgical bond with the broken-down surface of the metal window seat in step (2), thereby achieving welding and packaging of the transparent optical window piece and the metal window seat.

2. The method of encapsulating an optical window of claim 1, wherein, The computer control system controls the laser to generate a laser beam, which is focused on the upper surface of the metal window seat through the transparent optical window piece and scanned to achieve welding and packaging of the transparent optical window piece and the metal window seat.

3. The method of encapsulating an optical window of claim 1, wherein, The contact distance between the transparent optical window piece and the metal window seat in step (4) is less than 1mm.

4. The method of encapsulating an optical window of claim 2, wherein, By adjusting the line width and spacing of the laser scanning and the laser parameters, the welding and packaging strength of the transparent optical window piece and the metal window seat is adjusted.

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