BOX light source packaging structure and method based on parabolic concave reflection collimation laser

Abstract

The invention discloses a BOX light source packaging structure and method based on parabolic concave reflection collimation laser, the packaging structure comprises a BOX shell, a TEC, a heat dissipation block gasket, a COC chip, a parabolic concave reflector and a light-transmitting inclined window, the TEC is arranged on the inner wall of a base of the BOX shell, the COC chip is packaged on the surface of the cold end of the TEC through the heat dissipation block gasket, and the COC chip is arranged on the inner wall of the base of the BOX shell. The parabolic concave reflector is located in front of the transmitting end of the COC chip, the collimation direction of the parabolic concave reflector and the light emitting direction of a light source of the COC chip form a 90-degree angle, and the focus of the parabolic concave reflector coincides with a light outlet of the COC chip; a divergent beam emitted from a light outlet of the COC chip is emitted from the focus of the parabolic concave reflector, and is reflected by the parabolic concave reflector surface to form a collimated beam. Interference noise caused by reflection of the guide lens is effectively avoided, the sensitivity level of gas detection is improved, and large-scale production can be realized by using an existing production line.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of laser gas concentration detection, and particularly relates to a BOX light source packaging structure and method based on parabolic concave reflection collimation laser. BACKGROUND

[0002] In the fields of smart mines, city safety, gas leakage, chemical safety and the like, a large number of laser gas sensors with higher safety and sensitivity are needed; in the gas safety market, whether industrial or civil, high-precision, non-calibration and low-cost laser sensors are needed; in the fields of medical diagnosis, smart home and scientific research, laser gas sensors with higher sensitivity, faster response speed and wider applicability are needed.

[0003] The traditional gas detection methods on the market include semiconductor type, electrochemical type, catalytic combustion type and the like, and have problems such as low sensitivity, great influence of environmental factors, poor reliability and short service life. Based on the TDLAS laser sensing gas detection, the method has the advantages of small environmental factor interference, high reliability and long service life, and will gradually become the mainstream in the market in the future. All the laser light sources on the market with collimated light beams are coupled with ball lenses or aspheric lenses to collimate the light beams emitted by the laser chips. When the light beams must pass through the lenses for collimation, reflection is inevitably generated on the front and rear surfaces of the lenses. If the reflected light beams enter the laser resonant cavity, when the wavelength of the laser is tuned by the driving current, the output light beams of the laser will produce certain interference noise. For the TDLAS laser sensing technology, the interference noise reduces the signal-to-noise ratio of the received signals, seriously affects the measurement accuracy of the concentration of the absorbed gas, and thus makes it difficult to identify the detection signal when the concentration of the measured gas is low, thereby affecting the accuracy of the gas detection. Therefore, how to reduce the interference ripple of the light source and improve the accuracy of the laser gas sensor becomes a key technical problem to be solved.

[0004] In view of the technical challenge, the applicant adopts a rotary parabolic concave mirror to collimate the light beams in the Chinese patent application for packaging structure and packaging method and application of lensless coaxial TO-CAN collimation laser with the publication number CN119496036A, the light beams form parallel light beams after reflection, thereby avoiding the interference noise caused by the reflection of the lens surface and significantly improving the accuracy of the gas detection.

[0005] The above structure adopts the following packaging steps: first, fix the TO-CAN base and determine the light source reference surface; then install the TEC temperature controller, coupling heat sink gasket and laser chip, and ensure that the TEC temperature controller and the laser chip are powered on; then adjust the position of the parabolic concave mirror through the 6-dimensional adjustment frame, ensure that the focal point of the parabolic concave mirror is aligned with the light emitting point of the laser chip, then fix the parabolic concave mirror, and adjust the optical path to ensure the accuracy of the optical path.

[0006] In the above prior art, optical path calibration is a key step. The calibration process needs to manually adjust the position of the parabolic concave mirror through the 6-dimensional adjustment frame to ensure that the focal point of the parabolic concave mirror is aligned with the light emitting point of the laser chip. This process has the following problems in implementation:

[0007] 1. Lack of standardized reference

[0008] In the prior art, due to the lack of fixed reference surface and standardized alignment structure, there is no unified reference. Therefore, in the optical path calibration process, only the side of the concave mirror can be clamped by the clamp, and the focal point on the arc surface of the concave mirror can be adjusted and ensured to correspond to the light emitting point of the chip. Currently, only fine adjustment can be achieved by the adjustment frame, and a reusable mechanical positioning reference cannot be formed. This makes it necessary to manually calibrate each assembly, and the operation process relies on experience, making it difficult to ensure accuracy and consistency.

[0009] 2. Dependence on manual adjustment

[0010] The TO-can optical path calibration of the prior art completely depends on manual adjustment, which requires manual adjustment through special equipment (6-dimensional adjustment frame). The operator needs to observe the light emitting effect and adjust the mirror position multiple times. Although this method can achieve high-precision optical path matching, the calibration process is complex, time-consuming, and requires high personnel experience.

[0011] 3. Cannot realize large-scale automated production

[0012] Due to the above defects of lack of standardized reference and complete dependence on manual adjustment, it is difficult to adapt to traditional automated assembly processes, and the positioning of the mirror and the alignment of the optical path cannot be completed by automatic equipment such as mechanical hands and suction cups, making it difficult to realize large-scale automated production. At the same time, manual calibration inevitably accumulates deviations, and the optical path alignment accuracy of different batches of products has slight differences, affecting the overall light emitting consistency and the batch stability control of product performance.

[0013] 4. Complex packaging process, large space occupation, and limited miniaturization design.

[0014] 5. Poor heat dissipation effect, which affects the stability and long-term reliability under high-power working conditions due to heat accumulation.

[0015] Therefore, how to design a laser package structure without relying on manual adjustment, adapting to automatic assembly process and greatly reducing the package size under the premise of ensuring laser collimation effect and optical path stability has become a technical problem to be solved in the field. SUMMARY

[0016] To solve the technical problems existing in the prior art, the purpose of the present application is to provide a BOX light source packaging structure and method based on parabolic concave reflection collimated laser, which is based on the TDLAS laser gas sensing principle, and provides a small laser gas detection collimated light source packaging structure and technology based on the BOX parabolic concave mirror structure. On the basis of not using optical lenses, according to the first physical principle that the divergent light beam of the laser is emitted from the focus of the parabola and reflected by the parabolic concave mirror, a collimated light beam is formed. The developed parabolic concave mirror packaged collimated laser effectively avoids the interference noise caused by lens reflection, greatly improves the sensitivity level of gas detection, and solves the problem of insufficient gas detection sensitivity caused by lens interference.

[0017] The purpose of the present application is achieved by the following technical scheme: a BOX light source packaging structure based on parabolic concave reflection collimated laser, comprising a BOX shell, a TEC, a heat sink gasket, a COC chip, a parabolic concave mirror and a protective light-transmitting inclined window, the cavity of the BOX shell accommodating the TEC, the heat sink gasket, the COC chip and the parabolic concave mirror; the TEC is arranged on the inner wall of the base of the BOX shell, the COC chip is packaged on the cold end surface of the TEC through the heat sink gasket, the parabolic concave mirror is located in front of the emission end of the COC chip, the collimation direction of the parabolic concave mirror is 90° to the light source light emitting direction of the COC chip, and the focal point of the parabolic concave mirror coincides with the light outlet of the COC chip; the divergent light beam emitted from the light outlet of the COC chip is emitted from the focal point of the parabolic concave mirror, reflected by the surface of the parabolic concave mirror, and forms a collimated light beam, the optical axis of the collimated light beam coincides with the optical path center of the BOX light outlet window, the BOX light outlet window is arranged on the front wall of the BOX shell, and the BOX light outlet window is provided with the light-transmitting inclined window.

[0018] Further, the light outlet of the COC chip is arranged at the focal point of the parabolic concave mirror, the central optical axis of the laser beam forms a 90° angle with the optical axis of the parabolic concave mirror, so that the laser beam with a certain divergence angle emitted by the COC chip is reflected and converged by the parabolic concave mirror and then output in the form of a collimated light beam, the optical axis of the parabolic concave mirror is parallel to the optical axis of the output collimated light beam and the central optical axis of the BOX shell.

[0019] Specifically, the parabolic concave mirror is an off-axis parabolic concave mirror formed by rotating a parabola around the principal axis of the parabola by a certain angle with the principal axis as the central axis; the parabolic concave mirror is formed by stamping a mirror surface steel or by injection molding and then forming a parabolic concave mirror by plating a light reflecting film.

[0020] Specifically, the upper cover is further included, which covers the upper opening of the BOX shell to form a sealed cavity, and the surface of the BOX shell relative to the upper cover is the inner wall of the base; the COC chip includes a laser chip and a COC, the laser chip is bonded on the COC, the COC is arranged on the heat sink gasket, the heat sink gasket is packaged on the cold end surface of the TEC, and the parabolic concave mirror for collimating the light beam is also arranged on the cold end surface of the TEC, and the hot end surface of the TEC is arranged on the inner wall of the base.

[0021] Further, the planes on both sides of the parabolic concave mirror are respectively parallel to the plane formed by the central optical axis of the laser beam and the optical axis of the parabolic concave mirror, so that the parabolic concave mirror can be arranged on the cold end surface of the TEC.

[0022] Specifically, the light-transmitting inclined window is made of an optical material capable of passing near-infrared and mid-infrared light beams and is coated with an anti-reflection film, and the angle between the normal line of the light-transmitting inclined window and the optical axis of the collimated light beam is greater than 8°.

[0023] Further, the circuit pins are arranged on both sides of the light path of the BOX light-emitting window, one side being the positive and negative electrodes of the TEC circuit and the other side being the positive and negative electrodes of the NTC resistor and the COC chip.

[0024] The application provides another technical solution to the technical problem: a BOX light source packaging method based on parabolic concave reflection collimated laser, and the steps are as follows:

[0025] Step 1: using the inner wall of the base of the BOX shell as an optical bonding collimating surface, and presetting a positioning area of a COC chip on the inner wall of the base, and sequentially stacking a TEC, a heat sink gasket and a COC chip on the positioning area of the inner wall of the base in a predetermined order, so that the COC chip is packaged on the cold end surface of the TEC through the heat sink gasket;

[0026] Step 2: sucking one side plane of a parabolic concave mirror, and bonding the other side plane of the parabolic concave mirror to a designated assembly position on the TEC with UV glue to realize the preliminary positioning of the parabolic concave mirror;

[0027] Step 3, before the UV glue is cured and after the parabolic concave mirror is initially positioned, the parabolic concave mirror is fine-tuned so that the light emitting point of the COC chip coincides with the focal point of the parabolic concave mirror.

[0028] Step 4, when the light emitting point of the COC chip coincides with the focal point of the parabolic concave mirror and the reflected parallel light beam forms a parallel light beam in the predetermined direction, the parabolic concave mirror is fixed.

[0029] Step 5, the circuit lead connection of the TEC and the COC chip is completed, the electrical integrity test is performed, the outer cover with a light-transmitting inclined window is assembled, the cover is sealed, the air tightness / dustproof measures are taken, and the packaging is completed.

[0030] Specifically, the parabolic concave mirror is adsorbed and fine-tuned by a mechanical hand; the fine-tuning operation means includes translation and rotation.

[0031] Further, Step 3 is to verify the collimation degree of the light beam through spot detection, power monitoring or light path stability to ensure that the output light beam meets the design optical performance requirements; Step 4 uses an automatic dispensing mechanism to apply positioning or structural glue between the base of the parabolic concave mirror and the heat dissipation block gasket, or uses a mechanical buckle / screw combined with adhesive to fix the parabolic concave mirror.

[0032] Compared with the prior art, the present application has at least the following beneficial effects:

[0033] 1. The parabolic concave mirror is used as the collimation of the light path of the light source, avoiding the use of near-infrared or mid-infrared focusing lenses in the light path, eliminating the light path interference caused by the reflection of the lens surface, greatly improving the sensitivity of gas detection, and solving the technical problem of low gas detection accuracy caused by lens surface interference.

[0034] 2. A small BOX packaging is used. In this BOX packaging, the 90° light path change of the parabolic concave mirror is used to make the collimation direction of the light path perpendicular to the BOX lead direction, and the positive and negative electrodes of the TEC are on different sides from the positive and negative electrode leads of the chip. In this way, all the placement spaces for setting various elements in the BOX are greatly utilized, and the entire BOX packaging structure is miniaturized.

[0035] 3. The light path collimation of the parabolic concave mirror makes this packaging design suitable for different wavelength detection light sources, unlike the lens packaging structure on the market today, which needs to match lenses of different materials due to different light source wavelengths.

[0036] 4、The technology is developed based on the first physical principle without using optical lens, and a small reflective packaged collimating BOX laser is developed, which greatly improves the sensitivity level of gas detection and realizes the detection precision from 4ppm to 0.1ppm level.

[0037] 5、The BOX packaging inner wall design forms a basic collimating surface, which facilitates the rapid positioning and installation of the chip. Further, the side wall plane design of the parabolic concave mirror is utilized to realize the calibration of the existing mass production line mechanism, so that the light emitting point of the COC chip and the focal point of the parabolic concave mirror can be automatically aligned without manual optical alignment, thereby ensuring the collimating precision and stability of the light beam. The parabolic concave mirror is used to turn the light beam by 90° and output it. The COC chip and the parabolic concave mirror are attached to the TEC cold end plane, and the TEC hot end plane is attached to the inner wall of the BOX packaging. The entire packaging layout is compact, realizing miniaturized packaging and maximizing the installation space.

[0038] During installation and calibration, the manipulator can quickly complete positioning and fine adjustment operations by adsorbing the parabolic concave mirror plane, without the need for special calibration tools, avoiding errors in manual calibration, greatly simplifying the operation process and improving work efficiency. Therefore, the scheme can be directly applied to the existing automatic production line to realize efficient mass production.

[0039] At the same time, the two side planes of the parabolic concave mirror are parallel to the plane where the central optical axis of the laser beam and the plane where the optical axis of the mirror itself are located, ensuring the precise alignment between the optical axis of the mirror and the laser light source, forming a clear geometric reference, making the light path calibration more accurate and efficient. On the other hand, through the parallel plane design, the light path alignment process is standardized, not only avoiding the slight deviation of the mirror during adjustment, but also ensuring the consistency of the optical performance of each packaging structure. The scheme is suitable for high-density, multi-wavelength and miniaturized laser products, taking into account the optical performance and production convenience, and has significant industrial application value.

[0040] 6、The BOX packaging shell side wall and the inclined window glass light outlet center serve as the optical reference of the outgoing light, so that the light emitting point of the COC chip and the focal point of the parabolic concave mirror are automatically aligned during assembly, and the manipulator adsorbs the parabolic concave mirror plane for rapid positioning and fine adjustment. Not only does it retain the advantages of parabolic concave mirror collimation in terms of optical performance, but it also realizes repeatable reference, automatic grabbing and placing, online closed-loop fine adjustment and rapid curing and fixing from a technological point of view, significantly improving the production efficiency and batch consistency of the packaging, meeting the needs of smart mines, city safety, gas leakage and chemical safety fields for high-sensitivity, low-noise and mass-produced laser gas sensors. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 Structure diagram of the package structure of the present application.

[0042] Figure 2 Structure diagram of the package structure of the present application with the upper cover removed.

[0043] Figure 3 Front view of the package structure of the present application with the upper cover removed.

[0044] Figure 4 Structure diagram of the TEC, heat sink gasket and COC chip of the package structure of the present application.

[0045] Figure 5 Sectional view of the package structure of the present application.

[0046] In the drawings:

[0047] 10 - BOX housing; 13 - base inner wall; 15 - light exit side wall; 17 - circuit pin wall; 19 - light exit window; 20 - TEC; 21 - TEC cold end surface; 22 - TEC hot end surface; 30 - heat sink gasket; 40 - COC chip, 41 - chip; 42 - COC; 50 - parabolic concave mirror; 60 - light-transmitting inclined window; 70 - circuit pin; 80 - upper cover. DETAILED DESCRIPTION

[0048] In order to facilitate the understanding of the present application, the technical solutions and advantages of the present application are further described in detail below in combination with the drawings and examples. The mechanisms or methods not described in the present application can refer to the prior art. The specific structure and features of the present application are described below by way of example, which should not constitute any limitation on the present application. At the same time, any one of the technical features mentioned below (including implied or disclosed), as well as any one of the technical features directly shown or implied in the drawings, can continue to be combined or deleted between these technical features, thereby forming more other embodiments that can not be directly or indirectly mentioned in the present application. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0049] As shown in Figures 1-5 the parabolic concave mirror-based collimated laser BOX light source package structure of the present embodiment includes a BOX housing 10, a chip temperature-controlled TEC 20, a heat sink gasket 30, a COC chip 40, a parabolic concave mirror 50, a protected light-transmitting inclined window 60, a circuit pin 70 and an upper cover 80.

[0050] Specifically, the BOX housing 10 is a container with an upper opening, which has a cavity, the TEC 20, the heat sink pad 30, the COC chip 40 and the parabolic concave mirror 50 are all arranged in the cavity. The upper cover 80 covers the upper opening of the BOX housing 10, the surface of the BOX housing 10 relative to the upper cover 80 is the base inner wall 13, and the four side walls of the BOX housing 10 are arranged around the base inner wall 13, one of which is the light-emitting side wall 15 with the light-emitting window 19, and the light-emitting window 19 is provided with the light-transmitting inclined window 60; the other pair of opposite side walls is the circuit pin wall 17.

[0051] The TEC 20 is arranged in the cavity of the BOX housing 10, and the TEC hot end surface 22 is attached to the base inner wall 13 of the BOX housing 10. The COC chip 40 is packaged on the TEC cold end surface 21 through the heat sink pad 30, the parabolic concave mirror 50 is located in front of the emitting end of the COC chip 40, and the collimation direction of the parabolic concave mirror 50 is at a 90° angle with the light-emitting direction of the light source of the COC chip 40. The focal point of the parabolic concave mirror 50 coincides with the light outlet of the COC chip 40, so that the divergent light beam emitted from the light outlet of the COC chip 40 is emitted from the focal point of the parabolic concave mirror 50, and after being reflected by the surface of the parabolic concave mirror 50, a collimated light beam is formed, and the optical axis of the collimated light beam is parallel to the base inner wall 13 of the BOX housing 10 and the two circuit pin walls 17, and is emitted from the protected light-transmitting inclined window 60 of the light-emitting window 19.

[0052] Specifically, the parabolic concave mirror 50 is an off-axis parabolic concave mirror formed by rotating a parabola around the major axis of the parabola at a certain angle with the major axis as the central axis. The parabolic concave mirror 50 is made of mirror steel punched into shape, or made by injection molding, and then coated with a reflective film to form the parabolic concave mirror 50. The COC chip 40 includes a laser chip 41 and a COC 42, the laser chip 41 is bonded on the COC 42, the COC 42 is arranged on the heat sink pad 30, and then packaged on the TEC cold end surface 21. The parabolic concave mirror 50 for collimating the light beam is also arranged on the TEC cold end surface 21, and the TEC hot end surface 22 is arranged on the inner wall 13 of the base of the BOX shell 10. The planes on both sides of the parabolic concave mirror 50 are parallel to the planes formed by the central optical axis of the laser beam and the optical axis of the parabolic concave mirror 50, respectively, so that the parabolic concave mirror 50 can be arranged on the TEC cold end surface 21. By designing in this way, the optical axis of the mirror and the laser light source are accurately aligned by using the parallel planes of the two sides of the parabolic concave mirror and the planes where the central optical axis of the laser beam and the optical axis of the mirror are located, forming a clear geometric reference, which makes the light path calibration more accurate and efficient.

[0053] Further, the stable output of the light beam can be ensured, and the problems of light beam scattering or focal point inaccuracy can be avoided, thereby ensuring reliable signal output and gas detection sensitivity. On the other hand, through the parallel plane design, the light path alignment process is standardized, not only avoiding the slight deviation of the mirror in the adjustment process, but also ensuring the consistency of the optical performance of each device, thereby improving the stability and quality control level of the products in batch production.

[0054] In addition, the light-transmitting inclined window 60 is made of an optical material that can pass near-infrared and mid-infrared light beams, such as sapphire and other materials, and is coated with an antireflection film. The angle between the normal line of the light-transmitting inclined window 60 and the optical axis of the collimated light beam is greater than 8 degrees.

[0055] Since the emission source of the COC chip 40 is located at the focal point of the parabolic concave mirror 50, the laser light source forms a collimated light beam through reflection of the parabolic concave mirror 50. The parabolic concave mirror 50 reflects the light beam with a certain divergence angle emitted by the light source into a collimated light beam with an optical axis of 90°. Moreover, the optical axis of the parabolic concave mirror 50 is parallel to the optical axis of the output collimated light beam and the inner wall 13 of the base of the BOX shell 10 and the two circuit pin side walls 17.

[0056] The circuit pin 70 is arranged on both sides of the light path of the light exit window 19, that is, the two end walls 17 of the BOX shell 10, one side being the positive and negative electrodes of the TEC circuit, and the other side being the positive and negative electrodes of the NTC resistor and the COC chip. In the embodiment, the working temperature of the COC chip 40 is controlled by the TEC 20, so that the light-emitting COC chip 40 is in a stable working temperature environment; at the same time, the parabolic concave mirror 50 is placed in the form of being attached to the inner wall 13 of the base, which not only facilitates packaging, but also makes the light path rotate by 90° and collimate output, so that the entire laser can be miniaturized and packaged.

[0057] In the working process of the BOX laser light source collimation packaging design product, the COC chip 40 is driven to emit light by connecting the external driving current through the circuit pin 70. The light source with a certain divergence angle is emitted on the parabolic concave mirror 50, and the light path is rotated by 90° by the reflection and convergence of the parabolic concave mirror 50, and at the same time, the light source with an emission angle becomes parallel light after passing through the parabolic concave mirror 50 and is output through the light-transmitting inclined window 60 on the BOX. The light source output collimated light in this packaging design is received by the detector, and since there is no lens interference, the light intensity of the feedback light can be accurately and stably fed back, so as to improve the detection accuracy of the gas.

[0058] In the embodiment, the parabolic concave mirror is used instead of the lens to serve as a collimation element and the BOX is used for packaging. The entire light path does not have any lens, which fundamentally solves the problem of noise interference caused by lens interference and improves the detection accuracy. At the same time, in the lens collimation laser on the market, different collimation lenses with different transmittance materials and curvature radii need to be selected for laser light sources with different wavelengths. This feature not only increases the material cost, but also increases the difficulty of selecting the collimation lens. When the parabolic concave mirror is used for collimation of the laser, the parabolic concave mirror only collimates and outputs the light beam and can collimate the light beam of any laser wavelength, that is, the parabolic concave mirror will not affect its reflection and collimation function with different laser wavelengths. Therefore, the light path design of the embodiment is suitable for all different wavelength laser chips, so that one packaging structure can be used to detect multiple gases.

[0059] The packaging steps of the embodiment are as follows:

[0060] Step 1: Positioning and installation of the COC chip 40;

[0061] The inner wall 13 of the base of the BOX shell 10 is used as an optical attachment collimation surface, and a positioning area of the COC chip 40 is preset on the inner wall 13 of the base. The temperature-controlled TEC 20, the heat sink gasket 30 and the COC chip 40 are sequentially stacked and installed in the positioning area in a predetermined order, so as to ensure that the light exit point of the COC chip 40 forms a structured reference and realizes accurate positioning and installation of the COC chip 40.

[0062] Step 2: Parabolic concave mirror 50 preliminary positioning;

[0063] The mechanical hand with suction cups sucks one side of the parabolic concave mirror 50, and the other side of the parabolic concave mirror 50 is adhered to the designated assembly position on the TEC cold end surface with UV glue, realizing the preliminary positioning of the parabolic concave mirror 50. Since the BOX shell 10 and the parabolic concave mirror 50 are pre-designed to match the geometric structure, the parabolic concave mirror 50 is placed in position to make its focal point and the light emitting point of the COC chip 40 preliminarily coincide, thereby completing the structural alignment.

[0064] Step 3: Optical path calibration adjustment;

[0065] Before the UV glue is cured and after the preliminary positioning of the parabolic concave mirror 50 is completed, the mechanical hand continues to maintain the adsorption of the parabolic concave mirror 50, and through translation, rotation and other fine adjustment operations, the light emitting point of the COC chip and the focal point position of the parabolic concave mirror are overlapped. In this process, the degree of beam collimation can be verified by spot detection, power monitoring or optical path stability to ensure that the output beam meets the design optical performance requirements.

[0066] Step 4: Fixing and curing;

[0067] When the light emitting point of the COC chip 40 and the focal point position of the parabolic concave mirror 50 are confirmed to be overlapped and the criterion beam is parallel to the base inner wall 13 and the two circuit pin side walls 17, an automatic dispensing mechanism is used to apply positioning or structural glue between the base of the parabolic concave mirror 50 and the TEC cold end surface 21, or a mechanical buckle / screw combined with glue is used to fix the parabolic concave mirror 50.

[0068] Step 5: Wiring and capping;

[0069] After completing the connection of the TEC 20, the COC chip 40 and other circuit leads 70, and doing electrical integrity test, assembling the outer cover with inclined window 60 or light-transmitting inclined window 60, and capping the cover 80, the air tightness / dustproof measures are taken, and the packaging is completed.

[0070] The application is based on tunable diode laser absorption spectroscopy (TDLAS) and uses laser light source collimation packaging with parabolic concave mirror structure, fully utilizes the outstanding advantages of the technology, and realizes the technical purposes of high sensitivity, miniaturization and simultaneous use for multiple gas measurement. Since the application uses BOX packaging collimation of parabolic concave mirror, the packaging can be suitable for light source selection of different kinds of gas detection wavelengths. That is, the same packaging design can be used for methane, ethane, acetylene and other gases, and can also be used for CO, CO2 and other gas detection. Therefore, the applicability of the design is greatly improved. At the same time, the parabolic concave mirror turns the light path by 90°, which can greatly miniaturize the packaging structure.

[0071] The application overcomes the technical problems that the laser with ball lens collimation packaging as a gas detection light source cannot eliminate the influence of lens on the light source from the root, and thus cannot detect the gas with high sensitivity. A BOX parabolic concave mirror structure packaging technology is proposed, which uses light emitted from the focal point of the parabolic concave mirror, collimates and outputs after reflecting the circular arc surface without penetrating the parabolic concave mirror, to avoid the interference of the mirror to the emitted light.

[0072] The application realizes three important innovations: first, the parabolic concave mirror designed by the parabolic concave mirror is used as the collimation of the light path of the light source, which avoids using the focusing lens suitable for near-infrared and mid-infrared, eliminates the light path interference caused by the reflection of the lens surface, and greatly improves the sensitivity of gas detection; second, the miniaturized BOX packaging is used, in which the 90-degree light path change of the parabolic concave mirror is used to make the collimation direction of the light path perpendicular to the lead direction of the BOX, and the positive and negative electrodes of the TEC are different from the positive and negative electrode leads of the chip, so that the placement space of all components is greatly utilized, and the miniaturization of the entire packaging structure is possible. Third, the light path collimation of the parabolic concave mirror makes the packaging design suitable for different wavelength detection light sources, instead of using the lens packaging structure on the market which needs to match different lenses due to different light source wavelengths.

[0073] The above embodiments are only preferred embodiments of the application, and cannot be used to limit the scope of protection of the application. For those skilled in the art, it can be understood that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the application, and the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A BOX light source package structure for collimating laser light based on a parabolic concave reflection, characterized by, The application relates to a BOX shell, a TEC, a heat dissipation block gasket, a COC chip, a parabolic concave mirror and a protected light-transmitting inclined window, wherein the cavity of the BOX shell contains the TEC, the heat dissipation block gasket, the COC chip and the parabolic concave mirror; the TEC is arranged on the inner wall of the base of the BOX shell; the COC chip is packaged on the cold end surface of the TEC through the heat dissipation block gasket; the parabolic concave mirror is located in front of the emitting end of the COC chip; the collimation direction of the parabolic concave mirror is 90 DEG to the light emitting direction of the light source of the COC chip; the focal point of the parabolic concave mirror is coincident with the light outlet of the COC chip; the divergent light beam emitted from the light outlet of the COC chip is emitted from the focal point of the parabolic concave mirror, is reflected by the surface of the parabolic concave mirror and forms a collimated light beam; the optical axis of the collimated light beam is coincident with the light path center of the light outlet window; the light outlet window is arranged on the front wall of the BOX shell; and the light outlet window is provided with the light-transmitting inclined window.

2. The BOX light source package structure based on parabolic concave reflection collimating laser according to claim 1, wherein, The light outlet of the COC chip is arranged at the focal point of the parabolic concave mirror; the central optical axis of the laser beam is 90 DEG to the optical axis of the parabolic concave mirror; the laser beam with a certain divergence angle emitted by the COC chip is reflected and converged by the parabolic concave mirror, is converted by 90 DEG and is output in the form of a collimated light beam, the optical axis of the parabolic concave mirror is parallel to the optical axis of the output collimated light beam and the central optical axis of the BOX shell.

3. The BOX light source package structure based on parabolic concave reflection collimating laser according to claim 1, wherein, the parabolic concave reflection collimating laser is arranged on the bottom of the BOX, and the BOX is arranged on the top of the parabolic concave reflection collimating laser. The parabolic concave mirror is an off-axis parabolic concave mirror formed by rotating a parabolic line around the main axis of the parabolic line by a certain angle; the parabolic concave mirror is formed by punching a mirror steel or by injection molding and then by plating a reflective film.

4. The BOX light source package structure based on parabolic concave reflection collimating laser according to claim 1, wherein, The application further comprises an upper cover which covers the upper opening of the BOX shell to form a closed cavity; the surface of the BOX shell relative to the upper cover is the inner wall of the base; the COC chip comprises a laser chip and a COC; the laser chip is bonded on the COC; the COC is arranged on the heat dissipation block gasket; the heat dissipation block gasket is packaged on the cold end surface of the TEC; the parabolic concave mirror for collimating the light beam is also arranged on the cold end surface of the TEC; and the hot end surface of the TEC is arranged on the inner wall of the base.

5. The BOX light source packaging structure based on parabolic concave surface reflection collimated laser as described in claim 4, characterized in that, The planes on both sides of the parabolic concave mirror are parallel to the plane formed by the central optical axis of the laser beam and the optical axis of the parabolic concave mirror, so that the parabolic concave mirror can be arranged on the cold end surface of the TEC.

6. The BOX light source package structure based on parabolic concave reflection collimating laser according to claim 1, wherein, The light-transmitting inclined window is made of optical material which can pass near-infrared and medium-infrared light beams and is coated with an antireflection film; the angle between the normal line of the light-transmitting inclined window and the optical axis of the collimated light beam is greater than 8 DEG.

7. The BOX light source package structure based on parabolic concave reflection collimating laser according to claim 1, wherein, The application further comprises circuit pins which are arranged on both sides of the light path of the light outlet window; one side is the positive and negative poles of the TEC circuit; and the other side is the positive and negative poles of the NTC resistance and the COC chip.

8. A BOX light source packaging method for collimating laser light based on a parabolic concave reflection, characterized by, The steps are as follows: Step 1, using the inner wall of the base of the BOX housing as an optical attachment collimating surface, and presetting the positioning area of the COC chip on the inner wall of the base, the TEC, the heat sink pad and the COC chip are stacked and installed in the predetermined order to the positioning area of the inner wall of the base, so that the COC chip is packaged on the cold end surface of the TEC through the heat sink pad; Step 2, absorbing one side of the parabolic concave mirror, and attaching the other side of the parabolic concave mirror to the designated assembly position on the TEC with UV glue to achieve the preliminary positioning of the parabolic concave mirror; Step 3, before the UV glue is cured and after the preliminary positioning of the parabolic concave mirror is completed, fine-tune the parabolic concave mirror so that the light emitting point of the COC chip coincides with the focal point of the parabolic concave mirror; Step 4, when the light emitting point of the COC chip coincides with the focal point of the parabolic concave mirror, and the reflected parallel light beam forms a parallel light beam in the predetermined direction, fix the parabolic concave mirror; Step 5, complete the circuit lead connection of the TEC and the COC chip and do the electrical integrity test, assemble the outer cover with the light-transmitting inclined window, and seal the cover, and take the air tightness / dustproof measures, complete the packaging.

9. The BOX light source packaging method based on parabolic concave reflection collimating laser according to claim 8, wherein, The adsorption and fine-tuning of the parabolic concave mirror are completed by a mechanical hand; the fine-tuning operation means includes translation and rotation.

10. The BOX light source packaging method based on parabolic concave reflection collimated laser light according to claim 8, wherein, Step 3 is to verify the collimation degree of the light beam through spot detection, power monitoring or light path stability to ensure that the output light beam meets the design optical performance requirements; Step 4 uses an automatic dispensing mechanism to apply positioning or structural glue between the base of the parabolic concave mirror and the heat sink pad, or uses mechanical buckles / screws combined with adhesive to fix the parabolic concave mirror.

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