CN107421647A - Common-path transmitting and receiving device for thermopile detector - Google Patents

Abstract

The invention discloses a common optical path transmitting and receiving device for a thermopile detector, comprising a laser emitting unit, a light concentrating receiving unit, a rotating base (11), and supporting arms (12). The light concentrating receiving unit includes Fresnel lens (1), multi-level reflector (2), homogenization rod (3), the laser emitting unit includes a first angler (4), a beam limiting diaphragm (5), a second angler (6), the laser (7) and the thermopile detector (8) are respectively installed in the emitting chamber (9) and the receiving chamber (10) and can be disassembled, and each of the components is assembled through the packaging shell and the corresponding supporting parts made. The present invention adopts a catadioptric-reflective secondary concentrating system composed of a Fresnel lens and a multi-stage reflector to increase the optical receiving efficiency of the echo light, and adopts a common optical path structure in which light beam emission and reception are integrated, which greatly reduces the The complexity of the system is reduced, the structure is simple and compact, and the manufacturing cost is low.

Description

Common optical path transmitting and receiving device for thermopile detector

technical field

The invention relates to the fields of optical design and infrared detection, in particular to a common optical path transmitting and receiving device for thermopile detectors.

Background technique

With the rapid development of the pipeline transportation industry, more and more attention has been paid to the safety of long-distance gas transmission pipelines. Pipeline leak detection technology is an important guarantee for the safe and stable operation of pipelines. Compared with traditional detection methods, the laser detection method based on near-infrared semiconductor absorption spectroscopy has the advantages of high sensitivity, fast response time, and strong selectivity, and can be combined with vehicle or airborne, and is increasingly used in long-distance gas transmission Remote sensing detection of pipeline leaks.

At present, the optical receiving system of most laser detectors regards the echo from the distant reflection target as a light parallel to the optical axis of the condenser lens. The facets are arranged in the focal plane of the condenser lens. However, in the actual detection process, due to the complex surface reflection of ground objects or pipelines and the influence of atmospheric turbulence on the laser echo, the reflected light will inevitably have a certain angle with the optical axis of the lens. If the refraction focusing lens is used alone as the light-collecting receiving device, the focus will shift due to the incident light deviation angle, which will affect the receiving efficiency of the photosensitive surface of the detector, resulting in a decrease in the detection sensitivity of the system.

Thermopile infrared detector is a kind of laser detection device commonly used in laser detection system. Its response to echo is only related to the received laser power and has nothing to do with the measured wavelength. Therefore, it has the advantage of wide response band. By installing different The optical filter can realize the laser detection of different wavelengths, and at the same time, it can work at room temperature without refrigeration. However, the diameter of the photosensitive surface of ordinary thermopile infrared detectors is usually only 10mm, and there is a lack of corresponding optical receiving system. The echo receiving efficiency of thermopile infrared detectors used in infrared detection systems is extremely low, and it cannot work normally in the process of trace gas detection. run.

Contents of the invention

In order to realize the integration of laser emission and reception, the present invention provides a common optical path transmitting and receiving device for thermopile detectors, the common optical path transmitting and receiving device for thermopile detectors adopts Fresnel lens and multi-stage The catadioptric-reflective secondary concentrating system composed of reflectors increases the optical reception efficiency of the echo light, and adopts a common optical path structure that integrates beam emission and reception, which greatly reduces the complexity of the system and makes the structure simple and compact. Manufacturing costs are low.

The technical solution adopted by the present invention to solve the technical problem is: a common optical path transmitting and receiving device for thermopile detectors, including a light collecting and receiving unit and a laser emitting unit; Fresnel lens, multi-stage reflector, homogenization rod and thermopile detector arranged in sequence in the direction, the multi-stage reflector and homogenization rod are cylindrical structures with open ends, the inner surface of the multi-stage The inner surface of the light rod is a reflective surface, and the optical axis of the Fresnel lens, the axis of the multi-level reflector and the axis of the uniform light rod are all coincident with the main optical axis; the laser emitting unit can emit light that coincides with the main optical axis. The laser beam is emitted in the negative direction of the principal optical axis.

The Fresnel lens is located in the entrance end of the multi-stage reflector, the focus of the Fresnel lens is located in the exit end of the multi-stage reflector, and the entrance end of the uniform light rod is correspondingly connected with the exit end of the multi-stage reflector.

The inner diameter of the inlet end of the multi-stage reflector is larger than the inner diameter of the outlet end of the multi-stage reflector. Along the positive direction of the main optical axis, the multi-stage reflector contains the first section, the second section, the third section, the fourth section, Fifth, sixth, seventh, eighth and ninth paragraphs.

The inner surface of the first section has a cylindrical structure, and the inner surfaces of the second, third, fourth, fifth, sixth, seventh, and eighth sections have a cylindrical truncated structure. The inner diameters of the outlet ends of the third section, the fourth section, the fifth section, the sixth section, the seventh section and the eighth section decrease successively.

The ninth segment is the surface of revolution formed by the parabola rotating with the main optical axis as the axis; the equation corresponding to the parabola is: f(X)=-0.009496X ² -0.0331X+11.41; in this equation, X∈[0, twenty four].

The inner surface of the homogenization rod is a regular hexagonal prism, the axis of the regular hexagonal prism coincides with the main optical axis, the outlet end of the homogenization rod is connected with the light-sensitive surface of the thermopile detector, and there is a receiver in the outlet end of the homogenization rod room divider.

The laser emitting unit contains a laser emitter, a first angler, a beam limiting aperture and a second angler arranged in sequence, the second angler is located at the center of the Fresnel lens, and the first angler and the second angler can The laser beam emitted by the laser emitter is transformed into said laser beam coincident with the main optical axis.

The laser emitter and the first angler are located outside the multi-level reflector, the second angler is located inside the multi-level reflector, the beam limiting diaphragm is located on the side wall of the multi-level reflector, and the entrance of the first angler faces the laser emitter , the outlet end of the first corner is toward the inlet of the second corner, the outlet of the second corner is toward the negative direction of the main optical axis, the center of the Fresnel lens is provided with a central hole, and the outlet of the second corner is Located within the central bore, a beam limiting diaphragm is located between the exit end of the first cornerizer and the inlet end of the second cornerizer.

The common optical path transmitting and receiving device for thermopile detectors also includes a transmitting chamber and a receiving chamber, the receiving chamber is a cylindrical structure with at least one end open, the light concentrating receiving unit is arranged in the receiving chamber, the Fresnel lens and the receiving chamber Corresponding to the open end of , the main optical axis is in a horizontal state, the emitting chamber is fixed outside the upper part of the receiving chamber, and the laser emitter and the first angler are located in the emitting chamber.

The common optical path transmitting and receiving device for thermopile detectors also includes a rotating base and supporting arms. Connected by the damping knob, the receiving room can be rotated in the horizontal and vertical directions. The launching room is divided into front and rear parts, and a baffle is arranged between the front and rear parts. The rear part of the launch chamber.

The beneficial effects of the present invention are:

1. The plane reflectors of the first corner unit and the second corner unit are arranged coplanar up and down, and are at an angle of 45° to the optical axis. The laser light is emitted after secondary reflection and coincides with the optical axis of the receiving device, realizing the common transmission and reception. The optical path design improves the detection accuracy and makes the structure compact and small in size.

2. The optical reception adopts the combination of refraction-reflection secondary concentrating Fresnel lens and multi-level reflector, the effective reception angle is 5°, and the light transmittance is 70%, which improves the optical reception rate of echo light , thereby increasing the sensitivity of the infrared detection system.

3. The received light passes through the total reflection of the homogenizing rod, which makes the light spot on the photosensitive surface of the detector more uniform, effectively weakens the maximum irradiance intensity of the photosensitive surface, and reduces the loss of the photosensitive surface.

4. The laser and thermopile detectors can be disassembled, which is convenient for daily maintenance and repair.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention.

FIG. 1 is a schematic structural view of a common optical path transmitting and receiving device for a thermopile detector according to the present invention.

Fig. 2 is a schematic structural diagram of a multi-stage reflector.

Fig. 3 is a structural schematic diagram of a dodging rod.

Figure 4 is a schematic diagram of the installation of a thermopile detector.

Fig. 5 is a schematic structural diagram of a laser emitting unit.

Fig. 6 is a schematic diagram of the supporting structure of the transmitting chamber and the receiving chamber.

1. Fresnel lens; 2. Multi-level reflector; 3. Uniform rod; 4. First corner device; 5. Beam limiting diaphragm; 6. Second corner device; 7. Laser emitter; 8. Thermoelectric Stack detector; 9. Launching room; 10. Receiving room; 11. Rotating base; 12. Supporting arms; 13. Damping knob; 14. Main optical axis; 15. Partition of receiving room;

21. First paragraph; 22. Second paragraph; 23. Third paragraph; 24. Fourth paragraph; 25. Fifth paragraph; 26. Sixth paragraph; 27. Seventh paragraph; 28. Eighth paragraph; 29. ninth paragraph.

detailed description

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and examples.

A common optical path transmitting and receiving device for thermopile detectors, including a light-condensing receiving unit and a laser emitting unit; the light-condensing receiving unit contains Fresnel lenses 1, multi-stage, and sequentially arranged along the positive direction of the main optical axis 14 The reflector 2, the homogenization rod 3 and the thermopile detector 8, the multi-stage reflector 2 and the homogenization rod 3 are all cylindrical structures with open ends, the inner surface of the multi-stage reflector 2 and the inner surface of the homogenization rod 3 The surfaces are reflective surfaces, and the optical axis of the Fresnel lens 1, the axis of the multi-stage reflector 2 and the axis of the uniform light rod 3 are all coincident with the main optical axis 14; For the overlapping laser beams, the emission direction of the laser beams is the negative direction of the principal optical axis 14, as shown in FIG. 1 .

In this embodiment, the Fresnel lens 1 is located in the entrance port of the multi-stage reflector 2, the focus of the Fresnel lens 1 is located in the exit port of the multi-stage reflector 2, and the entrance port of the homogenizing rod 3 is connected with the multi-stage reflector. Corresponding connection to the outlet port of device 2. The entrance end of the multilevel reflector 2 and the entrance end of the homogenization rod 3 are all located on the left side of Fig. 1, and the outlet end of the multilevel reflector 2 and the exit end of the homogenization rod 3 are all located on the right side of Fig. 1, wherein the The Fresnel lens 1 is made of ppmm material, has a diameter of 80 mm, and a focal length of 150 mm. The Fresnel lens 1 is embedded in the entrance end of the multi-stage reflector 2 . The center of the Fresnel lens 1 is perforated for inlaying the second angler 6 .

In this embodiment, the inner diameter of the inlet end of the multi-stage reflector 2 is greater than the inner diameter of the outlet end of the multi-stage reflector 2. Along the positive direction of the main optical axis 14, the multi-stage reflector 2 contains nine sections connected in sequence, and the nine sections are respectively First paragraph 21 , second paragraph 22 , third paragraph 23 , fourth paragraph 24 , fifth paragraph 25 , sixth paragraph 26 , seventh paragraph 27 , eighth paragraph 28 and ninth paragraph 29 . The inner surface of the first section 21 has a cylindrical structure, and the inner surfaces of the second section 22, the third section 23, the fourth section 24, the fifth section 25, the sixth section 26, the seventh section 27 and the eighth section 28 have a cylindrical structure. Cylindrical frustum-shaped structure, the inner diameters of the outlet ends of the second section 22, the third section 23, the fourth section 24, the fifth section 25, the sixth section 26, the seventh section 27 and the eighth section 28 are successively reduced, and the multi-stage reflector The specific parameters of the inner surface of 2 are shown in Table 1.

Table 1

The ninth paragraph 29 is a surface of revolution formed by the parabola taking the main optical axis 14 as an axis; the equation corresponding to the parabola is: f(X)=-0.009496X ² -0.0331X+11.41; in this equation, X∈[ 0, 24], the unit is mm. The structure of the multi-stage reflector 2 is shown in FIG. 2 .

In this embodiment, the inner surface of the homogenization rod 3 is a regular hexagonal prism, the axis of the regular hexagonal prism coincides with the main optical axis 14, and the outlet end of the homogenization rod 3 is connected to the photosensitive surface of the thermopile detector 8, The outlet end of the dodging rod 3 is provided with a receiving chamber partition 15 . The outer surface of the homogenizing rod 3 is cylindrical, and the regular hexagonal prism is inscribed with the cylindrical shape, as shown in Figure 3, that is, the homogenizing rod 3 is a hollow cylindrical structure inscribed with a regular hexagon, and the multi-stage reflection The inner surfaces of the diffuser 2 and the dodging rod 3 are reflective mirror surfaces, and the reflective mirror surface is coated with a high-reflection film. diameter is the same as the outer diameter of the outlet end of the multi-stage reflector 2, and the outlet end of the receiving chamber partition 15 matches the uniform light rod 3, and the photosensitive surface of the thermopile detector 8 cannot be matched with the receiving chamber partition 15. The exit port of the homogenization rod 3 is in direct contact, and its rear end can only be located on the front side of the photosensitive surface of the thermopile detector 8 to avoid abrasion of the photosensitive surface, as shown in FIG. 4 .

In this embodiment, the laser emitting unit contains a laser emitter 7, a first angler 4, a beam limiting diaphragm 5 and a second angler 6 arranged in sequence, and the second angler 6 is located at the center of the Fresnel lens 1 , the first angler 4 and the second angler 6 can convert the laser beam emitted by the laser emitter 7 into the laser beam coincident with the main optical axis 14 . The laser emitter 7 is used to emit a laser beam, and the first angler 4 and the second angler 6 are used to change the angle of the laser beam emitted by the laser emitter 7 .

In this embodiment, the laser emitter 7 and the first corner 4 are located outside the multi-stage reflector 2, the second corner 6 is located inside the multi-stage reflector 2, and the beam limiting aperture 5 is located at the end of the multi-stage reflector 2. Side wall, the entrance end of the first angler 4 faces the emission port of the laser emitter 7, the outlet end of the first angler 4 faces the inlet end of the second angler 6, and the outlet end of the second angler 6 faces the main optical axis In the negative direction of 14, the center of the Fresnel lens 1 is provided with a central hole, the exit end of the second corner 6 is located in the center hole, and the beam limiting diaphragm 5 is located at the exit end of the first corner 4 and the second corner 4. Between the inlet ends of 6, the second angler 6 is located directly below the first angler 4.

Among them, the first corner 4 and the second corner 5 are both cylindrical structures with a diameter of 6 mm to 7 mm and a length of 10 mm. Plano-convex lenses and high reflection mirrors are installed inside, as shown in FIG. 5 . The first corner 4 is installed inside the launch chamber 9 , and the second corner 6 is embedded in the center of the Fresnel lens 1 . The plano-convex lens of the first angler 4 is positioned at one side near the laser emitter 7, and its main optical axis coincides with the center of the emitted laser beam. The high reflection mirror and the plano-convex lens main optical axis are at a 45° angle. A clear hole is set vertically below with a diameter of 5mm. The plano-convex lens of the second angler 6 is positioned at one side close to the Fresnel lens 1, and its main optical axis coincides with the main optical axis of the Fresnel lens. The reflector of 6 is provided with a light hole vertically above, with a diameter of 5mm. The beam limiting aperture 5 has a diameter of 5 mm and is installed at the opening of the receiving chamber 10 and the multi-stage reflector 2 directly below the light passage hole of the first corner 4 .

The horizontal laser beam emitted by the laser emitter 7 passes through the 90° reflection of the first angler 4, and the optical path changes to be vertically downward, passes through the beam limiting diaphragm 5, and passes through the 90° reflection of the second angler 6 again, and the optical path changes again. for horizontal rays. When the outgoing laser meets the object to be measured, it is diffusely reflected, after passing through the Fresnel lens 1 and the multi-level reflector 2, after the refraction-reflection secondary concentration, and then through the total reflection of the homogenizer 3, finally in the thermopile A uniform light spot is formed on the photosensitive surface of the detector 8 .

In this embodiment, the common optical path transmitting and receiving device for thermopile detectors also includes a transmitting chamber 9 and a receiving chamber 10, the receiving chamber 10 is a cylindrical structure with at least one end open, and the concentrating and receiving unit is arranged on the receiving chamber. In the chamber 10, the Fresnel lens 1 corresponds to the open end of the receiving chamber 10, that is, the Fresnel lens 1 of the light collecting and receiving unit is located in the left end of the receiving chamber 10 in Fig. 6, and the thermopile of the light collecting and receiving unit The detector 8 is located in the right end of the receiving chamber 10 in FIG. 6 . The main optical axis 14 is in a horizontal state, the emitting chamber 9 is fixed outside the upper part of the receiving chamber 10 , and the laser emitter 7 and the first angler 4 are located in the emitting chamber 9 .

The firing chamber 9 is divided into front and rear two parts, a baffle is arranged between the front and rear two parts, the first angler 4 is located in the front part of the firing chamber 9, and the laser emitter 7 is located in the rear part of the firing chamber 9. The baffle defines a light hole on the optical axis between the laser emitter 7 and the first corner 4 . The upper surface of the rear part of the emission chamber 9 can be opened or closed, so that the laser emitter 7 can be installed. The rear end of the receiving chamber 10 can be opened or closed for installing the thermopile detector 8 .

In this embodiment, the common optical path transmitting and receiving device for thermopile detectors also includes a rotating base 11 and supporting arms 12, the receiving chamber 10 is located above the rotating base 11, and between the receiving chamber 10 and the rotating base 11 Connected by the supporting arms 12, the supporting arms 12 are connected with the receiving chamber 10 through the damping knob 13, the receiving chamber 10 can rotate in the horizontal and vertical directions, and the receiving chamber 10 can take the straight line in the horizontal direction and the straight line in the vertical direction as axes turn.

Specifically, the rotating base 11 includes an inner circular plate and an outer square plate, and the lower ends of the supporting arms 12 are connected and fixed with the inner circular plate, and the receiving chamber 10 can rotate around the axis of the inner circular plate. The axis of the damping knob 13 is the shaft rotation. In this way, the up and down rotation of the transmitting and receiving device is realized by adjusting the damping knob 13, and at the same time, the supporting arms 12 are fixed on the turntable base 11, and the plane 360° adjustment can also be performed.

The above is only a specific embodiment of the present invention, and cannot limit the scope of the invention, so the replacement of its equivalent components, or the equivalent changes and modifications made according to the patent protection scope of the present invention, should still fall within the scope of this patent. category. In addition, the technical features and technical features, technical features and technical solutions, and technical solutions and technical solutions in the present invention can be used in free combination.

Claims (10)

1. a kind of common light path sending and receiving apparatus for thermopile detector, it is characterised in that the thermoelectric pile that is used for detects The common light path sending and receiving apparatus of device includes optically focused receiving unit and laser emission element；

The optically focused receiving unit contains the Fresnel Lenses (1) being arranged in order along the positive direction of primary optical axis (14), multiple levels of reflectors (2), optical tunnel (3) and thermopile detector (8), multiple levels of reflectors (2) and optical tunnel (3) are the tubular knot of both ends open Structure, the inner surface of multiple levels of reflectors (2) and the inner surface of optical tunnel (3) are reflecting surface, the optical axis of Fresnel Lenses (1), more The axis of level reflector (2) and the axis of optical tunnel (3) overlap with the primary optical axis (14)；

The laser emission element can launch the laser beam overlapped with primary optical axis (14), and the direction of the launch of the laser beam is key light The negative direction of axle (14).

2. the common light path sending and receiving apparatus according to claim 1 for thermopile detector, it is characterised in that Fei Nie You are located in the arrival end of multiple levels of reflectors (2) lens (1), and the focus of Fresnel Lenses (1) is located at going out for multiple levels of reflectors (2) Mouth end, the arrival end connection corresponding with the port of export of multiple levels of reflectors (2) of optical tunnel (3).

3. the common light path sending and receiving apparatus according to claim 1 for thermopile detector, it is characterised in that multistage The internal diameter of the arrival end of reflector (2) is more than the internal diameter of the port of export of multiple levels of reflectors (2), along the positive direction of primary optical axis (14), Multiple levels of reflectors (2) contain be sequentially connected first paragraph (21), second segment (22), the 3rd section (23), the 4th section (24), the 5th section (25), the 6th section (26), the 7th section (27), the 8th section (28) and the 9th section (29).

4. the common light path sending and receiving apparatus according to claim 3 for thermopile detector, it is characterised in that first The inner surface of section (21) is in cylindrical structural, second segment (22), the 3rd section (23), the 4th section (24), the 5th section (25), the 6th section (26), the inner surface of the 7th section (27) and the 8th section (28) is in cylindrical machine shape structure, second segment (22), the 3rd section of (23), the 4th The internal diameter of the port of export of section (24), the 5th section (25), the 6th section (26), the 7th section (27) and the 8th section (28) is sequentially reduced.

5. the common light path sending and receiving apparatus according to claim 3 for thermopile detector, it is characterised in that the 9th Section (29) is that parabola with primary optical axis (14) is that axle rotates the surface of revolution to be formed；

Equation corresponding to the parabola is：F (X)=- 0.009496X²-0.0331X+11.41；

In the equation, X ∈ [0,24].

6. the common light path sending and receiving apparatus according to claim 1 for thermopile detector, it is characterised in that even light The inner surface of rod (3) is positive six prismsby shape, and the axis of the positive six prismsby shape overlaps with primary optical axis (14), the outlet of optical tunnel (3) End is connected with the light sensation face of thermopile detector (8), and receiving chamber dividing plate (15) is provided with the port of export of optical tunnel (3).

7. the common light path sending and receiving apparatus according to claim 1 for thermopile detector, it is characterised in that this swashs Optical Transmit Unit contains the generating laser (7) set gradually, the first gyrator (4), beam-defining jaw (5) and the second gyrator (6), the second gyrator (6) is located at the center of Fresnel Lenses (1), and the first gyrator (4) and the second gyrator (6) will can swash The laser beam that optical transmitting set (7) is launched is changed into the laser beam overlapped with primary optical axis (14).

8. the common light path sending and receiving apparatus according to claim 7 for thermopile detector, it is characterised in that laser Transmitter (7) and the first gyrator (4) are located at multiple levels of reflectors (2) outside, and the second gyrator (6) is located in multiple levels of reflectors (2), Beam-defining jaw (5) is located at the side wall of multiple levels of reflectors (2), and the arrival end of the first gyrator (4) is towards generating laser (7), and The port of export of one gyrator (4) is towards the arrival end of the second gyrator (6), and the port of export of the second gyrator (6) is towards primary optical axis (14) negative direction, the center of Fresnel Lenses (1) are provided with centre bore, and the port of export of the second gyrator (6) is located at the centre bore Interior, beam-defining jaw (5) is located between the port of export of the first gyrator (4) and the arrival end of the second gyrator (6).

9. the common light path sending and receiving apparatus according to claim 7 for thermopile detector, it is characterised in that described Common light path sending and receiving apparatus for thermopile detector also includes bay (9) and receiving chamber (10), and receiving chamber (10) is At least tubular structure of one end open, the optically focused receiving unit are arranged in receiving chamber (10), Fresnel Lenses (1) and receiving chamber (10) open end is corresponding, and primary optical axis (14) is horizontal, and bay (9) is fixed on outside the top of receiving chamber (10), swashs Optical transmitting set (7) and the first gyrator (4) are located in bay (9).

10. the common light path sending and receiving apparatus according to claim 9 for thermopile detector, it is characterised in that institute State also includes rotating base (11) and support both arms (12), receiving chamber for the common light path sending and receiving apparatus of thermopile detector (10) it is located at the top of rotating base (11), by supporting both arms (12) to be connected between receiving chamber (10) and rotating base (11), Support both arms (12) are connected with receiving chamber (10) by damping knob (13), and receiving chamber (10) can turn in horizontally and vertically direction It is dynamic, it is divided into front and rear two parts in bay (9), baffle plate is provided between the front and rear two parts, the first gyrator (4) is located at bay (9) forward part, generating laser (7) are located at the rear part of bay (9).