Reflecting lens and gas sensor

Abstract

The utility model belongs to the technical field of gas sensors, and relates to a reflecting lens and a gas sensor, the reflecting lens comprises an optical lens base material, the optical lens base material is provided with a first surface, a second surface and an extinction surface, the first surface is divided into a first optical surface and a first mounting surface, and the second surface is divided into a second optical surface and a second mounting surface; the first optical surface and the second optical surface are inclined surfaces formed by performing wedge angle cutting on the optical lens base material from the first surface and the second surface respectively; the second optical surface and the first optical surface both have refraction and reflection functions and are parallel to the first optical surface. The delustering surface is formed after the optical lens base material is subjected to wedge angle cutting from the first surface and the second surface and the remaining uncut part of the side wall of the optical lens base material is subjected to delustering treatment; by designing the proportional relation of the extinction length h, the diameter d and the cutting reserved length K of the reflection lens, light interference can be eliminated, and normal transmission of incident light and overall stable installation can be guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of gas sensors, in particular to a reflective lens and a gas sensor. Background Art

[0002] In the field of gas detector technology, laser gas sensors typically use tunable diode laser absorption spectroscopy (TDLAS) technology. For example, based on the current tuning principle of a tunable diode laser, by changing the driving current of the gas sensor, the wavelength of the light passing through can be made relatively stable, and the wavelength of this light can be precisely locked to the specific absorption peak of the gas to be measured. In this way, when the laser beam passes through the gas to be measured, due to the selective absorption characteristics of the gas molecules for infrared light, the laser energy will be attenuated to a certain extent. By measuring the magnitude of this attenuation, the concentration of the gas to be measured can be accurately calculated. To ensure the high measurement accuracy of laser gas sensors, laser gas sensors are usually designed to have a semi-transparent and semi-reflective mirror inside the laser gas sensor. In this way, after the laser light is emitted from the TDLAS laser and incident on the semi-transparent and semi-reflective mirror, a portion of the laser beam can be emitted from the sensor for external gas detection, and the other portion of the laser beam is reflected back into the laser through the semi-transparent and semi-reflective mirror to realize the self-test function. Understandably, laser gas sensors need to use semi-transmission and semi-reflection to refract and reflect the laser beam.

[0003] However, in practical applications, when the incident laser beam passes through the semi-transparent and semi-reflective mirror, light interference will occur, affecting the detection results. Although there are some methods on the market to eliminate light interference, such as basically cutting the lens into a wedge angle, the semi-transparent and semi-reflective mirror processed by this method will have at least the following problems during use:

[0004] Either the optical interference of the reflected light can be eliminated, but it is difficult to ensure its stable installation; or it is difficult to simultaneously ensure that there is no interference after the self-test light is output and the refracted laser signal is output normally for gas detection. Utility Model Content

[0005] The embodiments of the present invention aim to solve at least one of the technical problems existing in the prior art. One purpose of the embodiments of the present invention is to provide a reflective lens that can simultaneously eliminate the interference of reflected light, ensure the normal output of refracted light, and ensure overall stable installation.

[0006] In order to solve the above technical problems, the embodiment of the present utility model provides a reflective lens, which adopts the following technical solution:

[0007] The reflective lens comprises:

[0008] An optical lens substrate is cylindrical and has a first surface, a second surface, and a matte surface; the first surface is located on a side close to incident light and opposite to the second surface;

[0009] The first side is divided into:

[0010] a first optical surface having refraction and reflection functions; the first optical surface is an inclined surface formed by cutting the optical lens substrate at a wedge angle from the first surface; and

[0011] A first mounting surface is used for mounting in contact with the outside; the first mounting surface is formed by the uncut portion of the optical lens substrate on the first surface when the first optical surface is formed;

[0012] The second side is divided into:

[0013] a second optical surface having refractive and reflective functions and parallel to the first optical surface; the second optical surface is an inclined surface formed by cutting the optical lens substrate at a wedge angle from the second surface; and

[0014] A second mounting surface is used for mounting in contact with the outside; the second mounting surface is formed by the uncut portion of the optical lens substrate on the second surface when the second optical surface is formed;

[0015] The matte surface is formed by the uncut portion of the side wall of the optical lens substrate after the optical lens substrate is wedge-cut from both the first surface and the second surface and subjected to matte treatment;

[0016] When incident light is incident on the first optical surface, a portion of the incident light is reflected from the optical lens substrate by the first optical surface to form a first reflected light, and another portion of the incident light is refracted into the optical lens substrate and incident on the second optical surface to form a first refracted light;

[0017] A portion of the first refracted light is reflected from the second optical surface, within the optical lens substrate, toward the direction of the first reflected light, to the matte surface to form second reflected light, and is absorbed by the matte surface;

[0018] Another portion of the first refracted light is refracted out of the optical lens substrate through the second optical surface to form a second refracted light.

[0019] In some embodiments of the present invention, the maximum uncut length of the optical lens substrate on the first mounting surface is defined as a cutting reserved length K; the maximum height of the matte surface close to the first mounting surface is defined as a matte length h;

[0020] The extinction length h is greater than a first preset multiple of the cutting reserved length K, so that the first refracted light can be refracted from the optical lens substrate to produce the second refracted light;

[0021] The diameter d of the reflective lens is smaller than a second preset multiple of the reserved cutting length K, so that the second reflected light is incident on the matte surface and absorbed by the matte surface;

[0022] The reserved cutting length K is the maximum vertical distance from the intersection of the first optical surface and the first mounting surface to the nearest matte surface;

[0023] The extinction length h is the minimum height difference between the first mounting surface and the second optical surface;

[0024] The diameter d of the reflective lens is the maximum vertical distance from the intersection line of the first optical surface and the matte surface on one side to the matte surface on the other side.

[0025] In some embodiments of the present invention, the refraction angle θ2 of the first refracted light satisfies the following formula 1:

[0026] θ2=arcsin(n1*sinθ1 / n2)

[0027] Wherein, n1 is the refractive index of air, n2 is the refractive index of the material of the optical lens substrate; the incident light is incident on the first optical surface perpendicular to the first surface, so that the incident angle θ1 of the incident light is 45°;

[0028] When the second refracted light exits the second optical surface parallel to the incident light, the extinction length h satisfies the following formula 2:

[0029] h>K*tan(θ2+θ4)

[0030] The first preset multiple is equal to tan(θ2+θ4); the first surface is cut at a wedge angle of 45° to form the first optical surface, so that the reflection angle θ4 of the first reflected light is 45°.

[0031] In some embodiments of the present invention, the refractive index of air is n1=1; when the optical lens substrate is made of glass, n2=1.5;

[0032] According to Formula 1, the refraction angle of the first refracted light is

[0033] According to Formula 2, and the values ​​of the refraction angle θ2 of the first refracted light and the reflection angle θ4 of the first reflected light, the extinction length h is greater than 3.29 times the reserved cutting length K.

[0034] In some embodiments of the present invention, when the refraction angle of the first refracted light is equal to the incident angle of the first refracted light, a portion of the second refracted light is emitted toward the first reflected light to the extinction surface, and a portion is emitted parallel to the incident light and exits the second optical surface, the diameter d of the reflective lens satisfies the following formula 3:

[0035] d <t*sin(θ3+θ5+θ7)

[0036] Wherein, in the formula 3, θ3=θ2, θ2=arcsin(n1*sinθ1 / n2), n1 is the refractive index of air, n2 is the refractive index of the material of the optical lens substrate, and the incident angle θ1 of the incident light is 45°;

[0037] The reflection angle of the second reflected light is θ5=θ3; at the intersection of the second optical surface and the matte surface, the angle between the first refracted light and the matte surface is θ7=90°-θ2-θ4, and the reflection angle of the first reflected light is θ4=θ1=45°;

[0038] The limit length t of the second reflected light is the length of the second reflected light from the intersection of the second optical surface and the matte surface to the intersection of the first optical surface and the matte surface, and t satisfies the following formula 4:

[0039] t=K*((cos(θ3+θ5)+sin(θ3+θ5)*tanθ6) / cos(θ4+θ2))

[0040] In Formula 4, the angle between the incident point of the incident light at the intersection of the first optical surface and the first surface and the perpendicular line of the second reflected light and the first optical surface is θ6, and θ6=θ3+θ5-θ2.

[0041] In some embodiments of the present invention, the refractive index of air is n1=1; when the material of the optical lens substrate is glass, n2=1.5, and the refractive angle of the first refracted light is

[0042] According to Formula 3 and Formula 4, the diameter d of the reflective lens is less than 3.52 times the reserved cutting length K.

[0043] In some embodiments of the present invention, the matte surface is a frosted surface;

[0044] Alternatively, a matte layer is provided on the peripheral wall of the optical lens substrate to form the matte surface.

[0045] In some embodiments of the present invention, the optical lens substrate is a cylinder; the first surface and the second surface are the top surface and the bottom surface of the optical lens substrate, respectively.

[0046] In some embodiments of the present invention, the first reflected light is reflected by the incident light from the first optical surface perpendicularly to the incident light;

[0047] The second refracted light is refracted by the incident light from the second optical surface parallel to the incident light;

[0048] And / or, the first reflected light and the first refracted light account for 4% and 96% of the energy of the incident light respectively.

[0049] To solve the above technical problems, the present invention further provides a gas sensor, which adopts the following technical solution:

[0050] The gas sensor comprises:

[0051] A main body, having a mounting cavity formed therein;

[0052] The above-mentioned reflective lens is installed in the installation cavity;

[0053] a reflector, installed in the installation cavity;

[0054] a laser, disposed on the body, for emitting incident light toward the first optical surface of the reflective lens;

[0055] A self-test detector is provided on the main body;

[0056] Part of the incident light is reflected by the first optical surface of the reflecting lens to the reflecting mirror, and then reflected by the reflecting mirror to the self-detection detector; another part of the incident light is refracted by the first optical surface and the second optical surface of the reflecting lens in turn, out of the reflecting lens, and passes through the body to the external detector for gas detection.

[0057] Compared with the prior art, the reflective lens and gas sensor provided by the embodiment of the present invention have the following beneficial effects:

[0058] The reflective lens is formed by dividing the first surface of the cylindrical optical lens substrate into a first optical surface and a first mounting surface through wedge cutting, and dividing the second surface into a second optical surface and a second mounting surface through wedge cutting. The second optical surface is parallel to the first optical surface, and ensures that the incident light from the first optical surface is refracted into the optical lens substrate and then reflected to the extinction surface through the second optical surface to be absorbed by the extinction surface. This helps to further ensure that the light within the optical lens substrate will not be refracted out of the optical lens substrate, thereby eliminating the light interference problem of the first reflected light and improving the accuracy of the detection results. At the same time, it ensures that another part of the first refracted light can be refracted out of the optical lens substrate through the second optical surface to form the second refracted light, and by reserving sufficient first mounting surface and second mounting surface to adapt to external parts, the stable installation of the reflective lens is ensured. Therefore, the reflective lens can not only avoid light interference, but also ensure that the optical lens substrate normally refracts the second refracted light, and also ensures stable installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the solutions in the present invention, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention or corresponding prior art. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work. Among them:

[0060] Figure 1 This is a schematic diagram of the three-dimensional structure of the reflective lens in an example of the present utility model from one viewing angle;

[0061] Figure 2 This is a schematic diagram of the three-dimensional structure of the reflective lens in another perspective of the present utility model;

[0062] Figure 3 is a three-dimensional cutaway view of a reflective lens in an example of the present utility model;

[0063] Figure 4 is a top view of the reflective lens in an example of the present utility model;

[0064] Figure 5 This is a light path diagram of the reflective lens in an example of the present invention when the incident light is incident at a special position and undergoes refraction and reflection; wherein the special position is the intersection between the first optical surface and the first mounting surface, and the first refracted light is incident at the intersection between the second optical surface and the matte surface, and the second reflected light is incident at the intersection between the first optical surface and the matte surface;

[0065] Figure 6 This is a light path diagram of the incident light of the reflective lens in the example of the present utility model when it is incident on the first optical surface and undergoes refraction and reflection;

[0066] Figure 7 This is a simplified structural diagram of the gas sensor in the example of the present utility model.

[0067] The reference numerals in the accompanying drawings are as follows:

[0068] 1000, gas sensor; 100, body; 200, reflecting lens; 300, reflecting mirror; 400, laser; 410, incident light; 411, first reflected light; 412, first refracted light; 4121, second reflected light; 41211, interference light; 4122, second refracted light; 500, self-test detector; 2000, external detector;

[0069] 1. Optical lens substrate; 11. First surface; 111. First optical surface; 112. First mounting surface; 12. Second surface; 121. Second optical surface; 122. Second mounting surface; 13. Matt surface. DETAILED DESCRIPTION

[0070] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this invention pertains; the terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this invention; for example, terms such as “length,” “width,” “up,” “down,” “left,” “right,” “front,” “back,” “vertical,” “horizontal,” “top,” “bottom,” “inside,” and “outside” indicate directions or positions based on those shown in the accompanying drawings, which are for ease of description only and are not to be construed as limiting this technical solution.

[0071] The terms "including," "having," and any variations thereof in the specification and claims of this utility model and the accompanying drawings are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the specification and claims of this utility model and the accompanying drawings are used to distinguish between different items, not to describe a particular order. "Multiple" means two or more, unless otherwise expressly specified.

[0072] In the specification and claims of this utility model and the above-mentioned description of the drawings, when an element is referred to as being “fixed to”, “mounted on”, “disposed on” or “connected to” another element, it may be directly or indirectly located on the other element. For example, when an element is referred to as being “connected to” another element, it may be directly or indirectly connected to the other element.

[0073] Furthermore, references to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0074] The embodiment of the present invention provides a reflective lens 200, which can be applied to the gas sensor 1000. For example, in a laser gas sensor, the reflective lens 200 can refract the laser beam emitted by the laser 400 to the external detector 2000 to achieve non-contact gas concentration detection.

[0075] Of course, the reflective lens 200 can also be applied to other suitable products, and is not particularly limited here. It only needs to ensure that the reflective lens 200 has both reflective and refracting functions and is suitable for corresponding scenarios that require reflection and refraction of light beams.

[0076] like Figures 1 to 3 As shown, the reflective lens 200 includes a cylindrical optical lens substrate 1 having a first surface 11, a second surface 12, and a matte surface 13. The first surface 11 is located on the side closer to the incident light 410 and opposite to the second surface 12. For example, to simplify the structure of the reflective lens 200, the optical lens substrate 1 is a cylinder, the first surface 11 is the top surface of the optical lens substrate 1, and the second surface 12 is the bottom surface of the optical lens substrate 1.

[0077] In the embodiment of the present utility model, Figure 3 and Figure 5 As shown, the first surface 11 is divided into a first optical surface 111 and a first mounting surface 112. Correspondingly, the second surface 12 is divided into a second optical surface 121 and a second mounting surface 122. The first optical surface 111 and the second optical surface 121 both have refractive and reflective functions, and the second optical surface 121 is parallel to the first optical surface 111 to eliminate the effects of light interference. To prevent interference of the reflected light reflected from the optical lens substrate 1, the first optical surface 111 is an inclined surface formed by cutting the optical lens substrate 1 at a wedge angle from the first surface 11. Correspondingly, the second optical surface 121 is an inclined surface formed by cutting the optical lens substrate 1 at a wedge angle from the second surface 12.

[0078] Furthermore, to facilitate installation of the reflective lens 200, the first mounting surface 112 is formed by the uncut portion of the optical lens substrate 1 on the first surface 11 when the first optical surface 111 is formed. Similarly, the second mounting surface 122 is formed by the uncut portion of the optical lens substrate 1 on the second surface 12 when the second optical surface 121 is formed. Both the first mounting surface 112 and the second mounting surface 122 are used for external contact installation. Thus, components used to connect and secure the reflective lens 200 can achieve secure installation of the reflective lens 200 by contacting the first mounting surface 112 and the second mounting surface 122.

[0079] Exemplarily, the component for connecting and fixing the reflective lens 200 may be a cylindrical hollow groove device, and a mating surface (not shown) that is compatible with the first mounting surface 112 and the second mounting surface 122 is provided in the cylindrical hollow groove device. By the contact between the mating surface and the corresponding first mounting surface 112 and the second mounting surface 122, the contact area between the reflective lens 200 and the cylindrical hollow groove device can be increased as much as possible, which is conducive to increasing the fitting force between the two, thereby improving the stability of the installation of the reflective lens 200.

[0080] In the embodiment of the present utility model, as Figures 1 to 3 As shown, the matte surface 13 is formed by the uncut portion of the side wall of the optical lens substrate 1 after the optical lens substrate 1 is wedge-cut from both the first surface 11 and the second surface 12 and subjected to matte treatment.

[0081] For example, when the optical lens substrate 1 is cylindrical, wedge-angle cutting can be performed obliquely from the top surface of the optical lens substrate 1, wherein the cutting starting position of the cutter is located inside the top surface of the optical lens substrate 1, and the cutting depth is less than the height of the optical lens substrate 1. In this way, the cutting surface formed by the cutter on the optical lens substrate 1 is the first optical surface 111, and the surface formed by the uncut portion of the top surface of the optical lens substrate 1 is the first mounting surface 112.

[0082] Similarly, the cutter's starting point for cutting is within the bottom surface of the optical lens substrate 1, and the cutting depth is less than the height of the optical lens substrate 1. Thus, the cut surface formed by the cutter on the optical lens substrate 1 is the second optical surface 121, and the surface formed by the uncut portion of the bottom surface of the optical lens substrate 1 is the second mounting surface 122. It is understood that the remaining uncut portion of the arcuate peripheral wall of the optical lens substrate 1 can be the matte surface 13.

[0083] It should be noted that, specifically in this embodiment, to achieve the matte surface 13's light-absorbing matte function, the matte surface 13 is a frosted surface, or a matte layer is provided on the peripheral wall of the optical lens substrate 1 to form the matte surface 13. Of course, in other embodiments, the peripheral wall of the optical lens substrate 1 may also be formed with the matte surface 13 using new or existing methods, which will not be specifically described here.

[0084] In the embodiment of the present utility model, as Figure 5 and Figure 6 As shown, when the incident light 410 (see Figure 5 or Figure 6 When a portion of the incident light 410 is incident on the first optical surface 111 and reflected from the optical lens substrate 1 by the first optical surface 111, the first reflected light 411 is formed (see FIG. Figure 5 or Figure 6 The other part of the incident light 410 is refracted into the optical lens substrate 1 and incident on the second optical surface 121 to form the first refracted light 412 (see Figure 5 or Figure 6 Yellow light separated from the blue light).

[0085] Since the second optical surface 121 has the functions of reflection and refraction, when the second optical surface 121 is set on the first refracted light 412, a portion of the first refracted light 412 can be reflected from the second optical surface 121, inside the optical lens substrate 1, toward the direction of the first reflected light 411, to the extinction surface 13 to form the second reflected light 4121 (see FIG. Figure 5 or Figure 6 Correspondingly, another portion of the first refracted light 412 can be refracted out of the optical lens substrate 1 through the second optical surface 121 to form a second refracted light 4122 (see Figure 5 or Figure 6 The yellow light is separated from the first reflected light 411).

[0086] It is understandable that, since the extinction surface 13 has the function of absorbing light, when the second reflected light 4121 hits the extinction surface 13, the second reflected light 4121 can be absorbed by the extinction surface 13. In this way, the reflective lens 200 does not generate interference light 41211 on the side where the first reflected light 411 is emitted (see FIG. Figure 5 The first reflected light 411 is prevented from being affected by the interference light 41211 refracted from the reflective lens 200 by the second reflected light 4121.

[0087] In summary, compared with the prior art, the reflective lens 200 has at least the following beneficial effects:

[0088] The reflective lens 200 is formed by dividing the first surface 11 of the cylindrical optical lens substrate 1 into a first optical surface 111 and a first mounting surface 112 through wedge cutting, and dividing the second surface 12 into a second optical surface 121 and a second mounting surface 122 through wedge cutting. The second optical surface 121 is parallel to the first optical surface 111, and ensures that the incident light 410 from the first optical surface 111 is refracted into the optical lens substrate 1 and then reflected by the second optical surface 121 to the extinction surface 13, so as to be absorbed by the extinction surface 13. This further ensures that the light within the optical lens substrate 1 does not refract out of the optical lens substrate 1, thereby eliminating the optical interference problem of the first reflected light 411 and improving the accuracy of the detection results. At the same time, it ensures that another portion of the first refracted light 412 can be refracted out of the optical lens substrate 1 through the second optical surface 121 to form the second refracted light 4122. By reserving sufficient first mounting surface 112 and second mounting surface 122 to adapt to external parts, the reflective lens 200 is securely installed. Therefore, the reflective lens 200 can not only avoid light interference, but also ensure that the optical lens substrate 1 normally refracts the second refracted light 4122 and can also ensure stable installation.

[0089] In order to make the technical personnel in this field better understand the present invention, the following Figures 1 to 6 , clearly and completely describe the technical solutions in the embodiments of the present utility model.

[0090] In some embodiments of the present invention, Figure 5 and Figure 6 As shown, the maximum uncut length of the optical lens substrate 1 on the first mounting surface 112 is defined as the cutting reserve length K. Figure 4 As shown, the reserved cutting length K is the maximum vertical distance from the intersection of the first optical surface 111 and the first mounting surface 112 to the nearest matte surface 13 .

[0091] like Figure 5 As shown, the maximum height of the extinction surface 13 close to the first mounting surface 112 is defined as the extinction length h. The extinction length h is the minimum height difference between the first mounting surface 112 and the second optical surface 121.

[0092] like Figure 5 As shown, when the optical lens substrate 1 is cylindrical, the diameter d of the reflective lens 200 (see Figure 4 ) is the maximum vertical distance from the intersection of the first optical surface 111 and the matte surface 13 on one side (eg, the left side) to the matte surface 13 on the other side (eg, the right side).

[0093] When designing the reflective lens 200, by ensuring that the extinction length h is greater than a first predetermined multiple of the reserved cutting length K, the first refracted light 412 can be refracted from the optical lens substrate 1 to produce the second refracted light 4122. Furthermore, by ensuring that the diameter d of the reflective lens 200 is less than a second predetermined multiple of the reserved cutting length K, the second reflected light 4121 can be directed to the extinction surface 13 and absorbed by the extinction surface 13.

[0094] It should be noted that, when parameters such as the incident angle of the incident light 410 and the reflection angle of the first reflected light 411 are determined, the value of the first preset multiplier is a fixed value; when parameters such as the refraction angle of the incident light 410, the reflection angle of the first reflected light 411, the incident angle of the first refracted light 412, and the reflection angle of the second reflected light 4121 are determined, the value of the second preset multiplier is a fixed value.

[0095] Understandably, when the reflective lens 200 is wedge-cut, by appropriately designing the ratio between the extinction length h and the reserved cutting length K, it is possible to quickly ensure that the incident light 410, upon entering the reflective lens 200, will refract to produce the second refracted light 4122. Furthermore, by appropriately designing the ratio between the diameter d of the reflective lens 200 and the reserved cutting length K, it is possible to quickly ensure that the incident light 410, upon entering the reflective lens 200, will not generate interference light 41211 that interferes with the first reflected light 411. Thus, while ensuring a sufficient reserved cutting length K to enhance the installation stability of the reflective lens 200, by adjusting the extinction length and / or the diameter d of the reflective lens 200 according to the aforementioned ratio, the reflective lens 200 can achieve both reflective and refractive functions and eliminate light interference. Furthermore, by reducing the diameter d of the reflective lens 200 according to the aforementioned ratio, the reflective lens 200 can be easily installed within a suitable installation space. In general, the reflective lens 200 can eliminate light interference, ensure normal transmission of the incident light 410 and ensure overall stable installation, which is conducive to improving the installation convenience, high fault tolerance and anti-falling performance of the reflective lens 200.

[0096] On the other hand, since the ratio between the diameter d, extinction length h and cutting reserved length K of the reflective lens 200 is generally fixed, the above ratio can be directly applied to design the reflective lens 200 according to different size requirements of different laser gas sensors 1000, which is conducive to simplifying the design and use process of the reflective lens 200 in different scenarios and facilitating the mass production of laser gas sensors 1000.

[0097] In some embodiments of the present invention, for example, to simplify the overall structure and facilitate the construction of the optical path, the first surface 11 may be cut at a 45° wedge angle to form the first optical surface 111, and the incident light 410 may be incident on the first optical surface 111 perpendicular to the first surface 11. In this case, the incident angle θ1 of the incident light 410 is 45°, and the reflection angle θ4 of the first reflected light 411 is 45°, so that the first reflected light 411 is emitted parallel to the first surface 11. That is,

[0098] like Figure 5 or Figure 6 As shown, according to the law of refraction, the following relationship exists between the incident angle θ1 of the incident light 410 and the refraction angle θ2 of the first refracted light 412: n1×sin(θ1)=n2×sin(θ2). Where n1 is the refractive index of air, and n2 is the refractive index of the material of the optical lens substrate 1. Therefore, it can be seen that the refraction angle θ2 of the first refracted light 412 satisfies the following formula 1:

[0099] θ2=arcsin(n1*sinθ1 / n2)………………………………Formula 1

[0100] Alternatively, in formula 1, θ1=45°, the refractive index of air n1=1, and when the material of the optical lens substrate 1 is glass, n2=1.5. Therefore, the refractive angle of the first refracted light 412 is That is, θ2 may be approximately equal to 28.13°.

[0101] Of course, in other examples, the incident angle θ1 of the incident light 410 may also adopt other values. The material of the optical lens substrate 1 is not limited to glass. Correspondingly, the refraction angle θ2 of the first refracted light 412 will be adaptively adjusted accordingly, which will not be elaborated here.

[0102] Also exemplarily, in order to facilitate the design of the first preset multiple between the extinction length h and the cutting reserved length K and to simplify the optical path construction of the gas sensor 1000, when the second refracted light 4122 can be normally transmitted, as shown in FIG. Figure 5As shown, the second refracted light 4122 can be designed to exit the second optical surface 121 parallel to the incident light 410. The second refracted light 4122 can exit from the intersection of the second optical surface 121 and the extinction surface 13. In other words, the first refracted light 412 enters the second optical surface 121 at the intersection of the second optical surface 121 and the extinction surface 13. Furthermore, the second reflected light 4121 can exit from the intersection of the second optical surface 121 and the extinction surface 13 to the intersection of the first optical surface 111 and the extinction surface 13. At the intersection of the first optical surface 111 and the extinction surface 13, the second reflected light 4121 can also be refracted by the first optical surface 111 to produce a dry light parallel to the first reflected light 411. For ease of calculation, the extinction length h in this case is set to the limit extinction length h1, and the diameter d of the reflective lens 200 is set to the limit diameter d1 of the reflective lens 200.

[0103] like Figure 5 As shown, assuming the length of the first refracted light 412 is z, according to the Pythagorean theorem: K 2 +h1 2 ＝ z 2 Wherein, h1 = K*tan(θ2+θ4). It can be understood that, while ensuring that the bonding surface between the reflective lens 200 and the outside is increased, that is, ensuring that there is a sufficient cutting reserve length K, if the incident light 410 is incident from any position on the first optical surface 111, the reflective lens 200 can refract the second refracted light 4122 parallel to the incident light 410, and the extinction length h satisfies the following formula 2:

[0104] h>K*tan(θ2+θ4)…………………………Formula 2

[0105] It can also be understood that the first predetermined multiple of the extinction length h and the reserved cutting length K is equal to tan(θ2+θ4) according to Formula 2. According to Formula 2, and the values ​​of the refraction angle θ2 of the first refracted light 412 and the reflection angle θ4 of the first reflected light 411, the extinction length h is greater than 3.29 times the reserved cutting length K.

[0106] For example, in Formula 2, as described above, the refraction angle of the first refracted light 412 is The reflection angle θ4 of the first reflected light 411 is 45°, so the value of the first preset multiple tan(θ2+θ4)=tan(28.13°+45°)=3.29, that is, h1=3.29K.

[0107] So it can be seen that when h>3.29K, for example, Figure 5 and Figure 6As shown, when the actual extinction length h2 of the extinction surface 13 is greater than the limit extinction length h1, that is, h2 > 3.29K, it can be ensured that when the incident light 410 is incident at any position on the first optical surface 111, there is always light refracted out of the reflecting lens 200 and will not enter the nearby extinction surface 13 and be absorbed.

[0108] Exemplarily, as Figure 5 shown, when the diameter d of the reflecting lens 200 is the limit diameter d1 of the reflecting lens 200, the length of the second reflected light 4121 at the limit position is set as the first limit length t, where the first limit length t is the length of the second reflected light 4121 from the intersection line of the second optical surface 121 and the extinction surface 13 to the intersection line of the first optical surface 111 and the extinction surface 13. The length of the first refracted light 412 at the limit position is set as the second limit length z, where the second limit length z is the length of the first refracted light 412 from the intersection line of the first optical surface 111 and the first mounting surface 112 to the intersection line of the second optical surface 121 and the extinction surface 13.

[0109] Again, as Figure 5 shown, the incident angle of the first refracted light 412 is θ3, and the reflection angle of the second reflected light 4121 is θ5; at the intersection line of the second optical surface 121 and the extinction surface 13, the angle between the first refracted light 412 and the extinction surface 13 is set as θ7. According to the Pythagorean theorem, the limit diameter d1 of the reflecting lens 200 = t * sin(θ3 + θ5 + θ7). It can be understood that when ensuring to increase the fitting surface between the reflecting lens 200 and the outside, that is, ensuring that there is enough cutting reserve length K, if the incident light 410 is incident from any position on the first optical surface 111, and part of the second refracted light 4122 can be directed towards the first reflected light 411 and absorbed by the extinction surface 13, and part is parallel to the incident light 410 and exits the second optical surface 121, the diameter d of the reflecting lens 200 satisfies the following formula 3:

[0110] d < t * sin(θ3 + θ5 + θ7) ………………………… formula 3

[0111] In formula 3, the first limit length t satisfies the following formula 4:

[0112] t = K * ((cos(θ3 + θ5) + sin(θ3 + θ5) * tanθ6) / cos(θ4 + θ2)) ……………… formula 4

[0113] As Figure 5 shown, according to the Pythagorean theorem, the second limit length z of the first refracted light 412 = k / cos(θ 2+ θ4), and the first limit length t of the second reflected light 4121 = cos(θ3 + θ5) * z +

[0114] sin(θ3 + θ5) * z * tanθ6, where, according to Formula 3 and Formula 4, the second preset multiple between the diameter d of the reflecting lens 200 and the cutting reserved length K satisfies the following Formula 5:

[0115] d < K * ((cos(θ3 + θ5) + sin(θ3 + θ5) * tanθ6) / cos(θ4 + θ2)) * sin(θ3 + θ5 + θ7)… Formula 5

[0116] It can be understood that from Formula 5, the value of the second preset multiple is as follows:

[0117] ((cos(θ3 + θ5) + sin(θ3 + θ5) * tanθ6) / cos(θ4 + θ2)) * sin(θ3 + θ5 + θ7)

[0118] where, according to the values of the respective angles, the diameter d of the reflecting lens 200 is greater than 3.52 times the cutting reserved length K. Of course, in other examples, the second preset multiple can also be other values, which will not be elaborated here specially.

[0119] Exemplarily, in Formula 3, the refraction angle θ2 of the first refracted light 412 is equal to the incident angle θ3 of the first refracted light 412, that is, θ3 = θ2, where θ2 = arcsin(n1 * sinθ1 / n2), n1 is the refractive index of air, n2 is the refractive index of the material of the optical lens substrate 1, and the incident angle θ1 of the incident light 410 = 45°.

[0120] Optionally, the refractive index n1 of air = 1, and when the material of the optical lens substrate 1 is glass, that is, n2 = 1.5, the refraction angle of the first refracted light 412 Also, since the reflection angle θ5 of the second reflected light 4121 = θ3, so, θ5 = θ3 = θ2 ≈ 28.13°.

[0121] In addition, according to the optical principle and geometric relationship, the reflection angle θ4 of the first reflected light 411 = θ1 = 45°, and the angle θ7 between the first refracted light 412 and the extinction surface 13 = 90° - θ2 - θ4 = 90° - 28.13° - 45° = 16.87°.

[0122] In Formula 4, set the perpendicular line from the incident point of the incident light 410 at the intersection line of the first optical surface 111 and the first surface 11 to the second reflected light 4121, and the angle between it and the first optical surface 111 is θ6, where θ6 = θ3 + θ5 - θ2 = 28.13°. Therefore, the second limit length z of the first refracted light 412 = k / cos(θ 2+θ4) = 3.45K, and the first limit length of the second reflected light 4121 is t = cos(θ3+θ5)*z+sin(θ3+θ5)*z*tanθ6≈3.68K. Therefore, d1 = t*sin(θ3+θ5+θ7)≈3.52K. Therefore, when d < 3.52K, the reflective lens 200 can eliminate the effects of optical interference when the incident light 410 is incident perpendicular to the first surface 11 at any position on the first optical surface 111, ensuring that a portion of the second refracted light 4122 is directed toward the first reflected light 411 and is absorbed by the extinction surface 13.

[0123] In some embodiments of the present invention, to simplify the optical path construction, the first reflected light 411 is reflected from the first optical surface 111 perpendicular to the incident light 410 by the incident light 410 , and the second refracted light 4122 is refracted from the second optical surface 121 parallel to the incident light 410 by the incident light 410 .

[0124] And / or, to meet the gas concentration detection requirements of gas sensor 1000 and ensure detection results, the energy proportions of first reflected light 411 and first refracted light 412 relative to the energy of incident light 410 are 4% and 96%, respectively. Of course, in actual applications, the energy proportions of first reflected light 411 and first refracted light 412 relative to the energy of incident light 410 can be determined based on actual needs and are not particularly limited herein.

[0125] Based on the above-mentioned reflective lens 200, as Figure 7 As shown, an embodiment of the present invention further provides a gas sensor 1000, which includes a body 100, the above-mentioned reflective lens 200, a reflective mirror 300, a laser 400, and a self-testing detector 500. A mounting cavity is formed inside the body 100, the above-mentioned reflective lens 200 and the reflective mirror 300 are both mounted in the mounting cavity, and the laser 400 and the self-testing detector 500 are both disposed in the body 100. The laser 400 can be used to emit incident light 410 toward the first optical surface 111 of the reflective lens 200, and the reflective mirror 300 can be used to reflect the first reflected light 411 reflected by the reflective lens 200 to the self-testing detector 500.

[0126] For example Figure 7 As shown, a portion of the incident light 410 is reflected by the first optical surface 111 of the reflecting lens 200 to the reflecting mirror 300, and is reflected by the reflecting mirror 300 to the self-detection detector 500; another portion of the incident light 410 is refracted out of the reflecting lens 200 by the first optical surface 111 and the second optical surface 121 of the reflecting lens 200, and passes through the main body 100 to the external detector 2000 for gas detection.

[0127] In summary, compared with the prior art, the gas sensor 1000 has at least the following beneficial effects: by adopting the above-mentioned reflecting lens 200, the gas sensor 1000 can not only reflect the first reflected light 411 through the reflecting lens 200 for the self-test detector 500 to perform real-time self-test, but also refract the second refracted light 4122 through the reflecting lens 200 for the external detector 2000 to perform gas detection, that is, the basic detection and self-test functions of the gas sensor 1000 can be realized; it can also well eliminate the optical interference of the first reflected light 411, which is not only conducive to ensuring the signal-to-noise ratio of the gas sensor 1000 signal, but also on the basis of strengthening the stable installation of the reflecting lens 200 in the main body 100, it can also reduce the diameter of the reflecting lens 200 according to the proportional relationship between the diameter of the reflecting lens 200 and the cutting reserved length K in the reflecting lens 200, which is conducive to the rapid installation of the reflecting lens 200 in a suitable space. In general, the gas sensor 1000 has high self-test accuracy, is easy to install, has a stable and reliable structure, and is easy to adapt the corresponding reflective lens 200 according to different sensor requirements, which is conducive to mass production.

[0128] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of the claims of the present invention.

Claims

1. A reflective lens, characterized in that: The reflective lens comprises: An optical lens substrate is cylindrical and has a first surface, a second surface, and a matte surface; the first surface is located on a side close to incident light and opposite to the second surface; The first side is divided into: a first optical surface having refraction and reflection functions; the first optical surface is an inclined surface formed by cutting the optical lens substrate at a wedge angle from the first surface; and A first mounting surface is used for mounting in contact with the outside; the first mounting surface is formed by the uncut portion of the optical lens substrate on the first surface when the first optical surface is formed; The second side is divided into: a second optical surface having refractive and reflective functions and parallel to the first optical surface; the second optical surface is an inclined surface formed by cutting the optical lens substrate at a wedge angle from the second surface; and A second mounting surface is used for mounting in contact with the outside; the second mounting surface is formed by the uncut portion of the optical lens substrate on the second surface when the second optical surface is formed; The matte surface is formed by the uncut portion of the side wall of the optical lens substrate after the optical lens substrate is wedge-cut from both the first surface and the second surface and subjected to matte treatment; When incident light is incident on the first optical surface, a portion of the incident light is reflected from the optical lens substrate by the first optical surface to form a first reflected light, and another portion of the incident light is refracted into the optical lens substrate and incident on the second optical surface to form a first refracted light; A portion of the first refracted light is reflected from the second optical surface, within the optical lens substrate, toward the direction of the first reflected light, to the matte surface to form second reflected light, and is absorbed by the matte surface; Another portion of the first refracted light is refracted out of the optical lens substrate through the second optical surface to form a second refracted light.

2. The reflective lens according to claim 1, wherein The maximum uncut length of the optical lens substrate on the first mounting surface is defined as the reserved cutting length K; the maximum height of the matte surface close to the first mounting surface is defined as the matte length h; The extinction length h is greater than a first preset multiple of the cutting reserved length K, so that the first refracted light can be refracted from the optical lens substrate to produce the second refracted light; The diameter d of the reflective lens is smaller than a second preset multiple of the reserved cutting length K, so that the second reflected light is incident on the matte surface and absorbed by the matte surface; The reserved cutting length K is the maximum vertical distance from the intersection of the first optical surface and the first mounting surface to the nearest matte surface; The extinction length h is the minimum height difference between the first mounting surface and the second optical surface; The diameter d of the reflective lens is the maximum vertical distance from the intersection line of the first optical surface and the matte surface on one side to the matte surface on the other side.

3. The reflective lens according to claim 2, wherein: The refraction angle θ2 of the first refracted light satisfies the following formula 1: θ2=arcsin(n1*sinθ1 / n2) Wherein, n1 is the refractive index of air, n2 is the refractive index of the material of the optical lens substrate; the incident light is incident on the first optical surface perpendicular to the first surface, so that the incident angle θ1 of the incident light is 45°; When the second refracted light exits the second optical surface parallel to the incident light, the extinction length h satisfies the following formula 2: h>K*tan(θ2+θ4) The first preset multiple is equal to tan(θ2+θ4); the first surface is cut at a wedge angle of 45° to form the first optical surface, so that the reflection angle θ4 of the first reflected light is 45°.

4. The reflective lens according to claim 3, wherein: The refractive index of air is n1=1; when the optical lens substrate is made of glass, n2=1.5; According to Formula 1, the refraction angle of the first refracted light is According to Formula 2, and the values ​​of the refraction angle θ2 of the first refracted light and the reflection angle θ4 of the first reflected light, the extinction length h is greater than 3.29 times the reserved cutting length K.

5. The reflective lens according to claim 2, wherein: When the refraction angle of the first refracted light is equal to the incident angle of the first refracted light, a portion of the second refracted light is emitted toward the first reflected light to the extinction surface, and a portion is emitted parallel to the incident light and exits the second optical surface, the diameter d of the reflective lens satisfies the following formula 3: d <t*sin(θ3+θ5+θ7) Wherein, in the formula 3, θ3=θ2, θ2=arcsin(n1*sinθ1 / n2), n1 is the refractive index of air, n2 is the refractive index of the material of the optical lens substrate, and the incident angle θ1 of the incident light is 45°; The reflection angle of the second reflected light is θ5=θ3; at the intersection of the second optical surface and the matte surface, the angle between the first refracted light and the matte surface is θ7=90°-θ2-θ4, and the reflection angle of the first reflected light is θ4=θ1=45°; The limit length t of the second reflected light is the length of the second reflected light from the intersection of the second optical surface and the matte surface to the intersection of the first optical surface and the matte surface, and t satisfies the following formula 4: t=K*((cos(θ3+θ5)+sin(θ3+θ5)*tanθ6) / cos(θ4+θ2)) In Formula 4, the angle between the incident point of the incident light at the intersection of the first optical surface and the first surface and the perpendicular line of the second reflected light and the first optical surface is θ6, and θ6=θ3+θ5-θ2.

6. The reflective lens according to claim 5, wherein: The refractive index of the air is n1=1; when the material of the optical lens substrate is glass, n2=1.5, and the refractive angle of the first refracted light is According to Formula 3 and Formula 4, the diameter d of the reflective lens is less than 3.52 times the reserved cutting length K.

7. The reflective lens according to claim 1, wherein: The matte surface is a frosted surface; Alternatively, a matte layer is provided on the peripheral wall of the optical lens substrate to form the matte surface.

8. The reflective lens according to claim 1, wherein The optical lens substrate is a cylinder; the first surface and the second surface are the top surface and the bottom surface of the optical lens substrate respectively.

9. The reflective lens according to claim 1, wherein: The first reflected light is reflected by the incident light from the first optical surface perpendicular to the incident light; The second refracted light is refracted by the incident light from the second optical surface parallel to the incident light; And / or, the first reflected light and the first refracted light account for 4% and 96% of the energy of the incident light respectively.

10. A gas sensor, characterized in that: The gas sensor comprises: A main body, having a mounting cavity formed therein; The reflective lens according to any one of claims 1 to 9, mounted in the mounting cavity; a reflector, installed in the installation cavity; a laser, disposed on the body, for emitting incident light toward the first optical surface of the reflective lens; A self-test detector is provided on the main body; Part of the incident light is reflected by the first optical surface of the reflecting lens to the reflecting mirror, and then reflected by the reflecting mirror to the self-detection detector; another part of the incident light is refracted by the first optical surface and the second optical surface of the reflecting lens in turn, out of the reflecting lens, and passes through the body to the external detector for gas detection.

Images