An optical fiber sensor

Abstract

The utility model belongs to sensor technical field discloses a kind of optical fiber sensors, including shell, reflector cup, focusing lens and optical fiber being arranged in shell;Reflector cup includes cup mouth, cup bottom and the cup wall being connected cup mouth and cup bottom, cup mouth is towards focusing lens setting, cup bottom is provided with light source;Reflector cup, light source, focusing lens and optical fiber are sequentially arranged along optical axis direction;Light source is used to produce light, light is reflected by reflector cup and forms parallel light;Focusing lens converges parallel light to the end surface of optical fiber.The utility model's optical fiber sensor, by the cup wall and cup bottom of reflector cup form closed reflection space, cup mouth is directly opposite focusing lens, so that light emitted by light source can be reflected and constrained as parallel light by cup wall regardless of how big divergence angle, avoid the problem that large-angle light is lost due to exceeding lens receiving range in traditional single-lens design, realize the maximization collection of light source energy, significantly improve coupling efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of sensor technology and relates to an optical fiber sensor. Background Technology

[0002] Fiber optic sensors are photoelectric sensors that use optical fibers to transmit light signals for detection. They offer advantages such as small size, flexibility, and resistance to electromagnetic interference, and are widely used in industrial automation, precision testing, and monitoring in confined spaces. Their basic working principle is as follows: light emitted from a light source is transmitted to the detection area via optical fiber. After being reflected or directly transmitted by the object being measured, the light signal is then transmitted back to the photoelectric conversion component via the receiving optical fiber, thereby determining the presence, position, or state of the target object.

[0003] The detection performance of fiber optic sensors is closely related to the fiber coupling efficiency, which directly determines the sensor's detection distance. Currently, commercially available fiber optic sensors typically use LEDs as the light source and employ lenses to refract the scattered light emitted by the LEDs onto the fiber end face to achieve optical signal coupling and transmission. However, LED light sources inherently exhibit large-angle divergence. Under existing technologies, because the lenses cannot fully collect the large-angle radiated light from the LEDs, a significant amount of light energy is wasted, resulting in a substantial reduction in the coupling efficiency between the LED and the fiber. This insufficient optical coupling efficiency directly limits the sensor's detection distance and signal response capability.

[0004] Therefore, there is an urgent need in this field for a fiber optic sensor to solve the above-mentioned technical problems. Utility Model Content

[0005] In view of this, the purpose of this utility model is to solve the problem that the insufficient optical coupling efficiency in the prior art limits the detection distance and signal response capability of the sensor.

[0006] This utility model provides an optical fiber sensor, including a housing, a reflector cup, a focusing lens and an optical fiber disposed within the housing; The reflective cup includes a cup mouth, a cup bottom, and a cup wall connecting the cup mouth and the cup bottom. The cup mouth is positioned facing the focusing lens, and a light source is provided at the cup bottom. The reflector cup, the light source, the focusing lens, and the optical fiber are arranged sequentially along the optical axis. The light source is used to generate light, which is reflected by the reflector cup to form parallel light; the focusing lens converges the parallel light to the end face of the optical fiber.

[0007] As a further improvement of this utility model, the cup wall is a parabola, and the bottom of the cup is connected to the focal plane of the parabola.

[0008] As a further improvement of this utility model, the parabolic equation of the cup wall is: ρ=2f / (1+cosα), where ρ is the polar radius, f is the focal length, and α is the angle between the parabola and the axis of symmetry.

[0009] As a further improvement of this utility model, the focusing lens includes an input surface and an output surface, wherein the input surface is a plane and the output surface is a convex surface.

[0010] As a further improvement of this utility model, the diameter of the cup opening is equal to the diameter of the light-incoming surface.

[0011] As a further improvement of this utility model, the end face of the optical fiber is located on the focal plane of the focusing lens.

[0012] As a further improvement of this utility model, the light source is located at the center of the bottom of the cup.

[0013] As a further improvement of this utility model, the light source is disposed on the bottom of the cup in a surface-mount or plug-in manner.

[0014] As a further improvement of this utility model, the light source is an LED light source.

[0015] As a further improvement of this utility model, the reflector cup is provided with an aluminum plating layer.

[0016] The technical advantages of this invention are as follows: Compared with existing technologies, the fiber optic sensor provided by this invention forms a closed reflection space through the cup wall and bottom of the reflector, with the cup opening facing the focusing lens. This structure ensures that light emitted from the light source, regardless of its divergence angle, can be reflected and constrained into parallel light by the cup wall, avoiding the problem of large-angle light loss due to exceeding the lens's receiving range in traditional single-lens designs, thus maximizing the collection of light source energy. The parallel light, after passing through the focusing lens, can be fully converged at the fiber end face, significantly improving coupling efficiency. High coupling efficiency significantly enhances the intensity of the optical signal transmitted through the fiber, supporting signal transmission over longer distances under the same attenuation conditions, solving the problem of limited detection distance caused by insufficient light energy in traditional sensors. The reflector, focusing lens, and optical fiber are integrated into the same housing, with the reflector and focusing lens coaxially arranged, eliminating the need for additional installation space. Compared to the traditional solution of increasing lens size to improve light-gathering capability, this structure maintains the sensor's miniaturization while improving performance, making it suitable for installation in confined spaces. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model, not all embodiments. For those skilled in the art, other drawings obtained from these drawings without creative effort are all within the protection scope of this utility model.

[0018] Figure 1 This is a perspective view of an optical fiber sensor provided in an embodiment of the present utility model; Figure 2 This is another perspective view of an optical fiber sensor provided in an embodiment of the present invention; Figure 3 This is a perspective view of the reflective cup provided in an embodiment of the present utility model; Figure 4 This is an optical path diagram of an optical fiber sensor provided in an embodiment of the present invention.

[0019] in, 10 is the reflector cup, 11 is the cup mouth, 12 is the cup bottom, 121 is the light source, 13 is the cup wall, 20 is the focusing lens, 21 is the light-entry surface, 22 is the light-exit surface, and 30 is the optical fiber. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0021] To make the description of this disclosure more detailed and complete, illustrative descriptions of the embodiments and specific examples of this utility model are provided below; however, this is not the only form of implementing or using the specific embodiments of this utility model. The embodiments cover the features of multiple specific embodiments and the methods, steps, and sequences for constructing and operating these specific embodiments. However, other specific embodiments can also be used to achieve the same or equivalent functions and sequence of steps. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0023] It should be understood that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this utility model described herein can be implemented in sequences other than those illustrated or described herein.

[0024] In the description of this utility model, the terms "front", "rear", "top", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0025] Please refer to Figures 1-4 One embodiment of this utility model provides an optical fiber sensor to solve the problem that insufficient optical coupling efficiency in the prior art limits the sensor's detection distance and signal response capability.

[0026] Specifically, please refer to Figure 1 A perspective view of an optical fiber sensor provided in an embodiment of this utility model. Figure 2 This is another perspective view of an optical fiber sensor provided by an embodiment of the present invention. The optical fiber sensor includes a housing (not shown), a reflector 10, a focusing lens 20, and an optical fiber 30 disposed within the housing. The reflector 10 includes a cup mouth 11, a cup bottom 12, and a cup wall 13 connecting the cup mouth 11 and the cup bottom 12. The cup mouth 11 is disposed facing the focusing lens 20. Please refer to [link to relevant documentation]. Figure 3 The bottom 12 of the cup is provided with a light source 121; the reflector cup 10, the light source 121, the focusing lens 20, and the optical fiber 30 are arranged sequentially along the optical axis. The core structure of the sensor is integrated into a housing, with the reflector cup 10, the light source 121, the focusing lens 20, and the optical fiber 30 arranged sequentially along the optical axis inside. All components are coaxially arranged to ensure optical path stability. Among them, the reflector cup 10, as a key optical element, is composed of a cup mouth 11, a cup bottom 12, and a cup wall 13 connecting the two. The cup mouth 11 faces the focusing lens 20, and the light source 121 is fixed in the center of the cup bottom 12, forming a coaxial layout of the light source 121, the reflector cup 10, the focusing lens 20, and the optical fiber 30.

[0027] In the fiber optic sensor provided in this embodiment of the present invention, the preferred assembly method is as follows: First, the reflector cup 10 and the focusing lens 20 are pre-aligned on the outside of the housing and packaged into an independent and stable optical module. Then, the integrated module is positioned and installed inside the sensor housing, while the light source 121 is fixed at the center of the bottom 12 of the reflector cup. The optical fiber 30 is independently fixed and positioned by the structure of the housing itself. This design ensures the coaxiality and long-term stability of the optical axis of the light source, reflector cup, and lens through modular packaging, and simplifies the assembly process by using the separate installation of the optical fiber, thereby improving production consistency and maintenance convenience.

[0028] The light source 121 generates light, which is reflected by the reflector cup 10 to form parallel light. The focusing lens 20 converges the parallel light to the end face of the optical fiber 30. The diverging light generated by the light source 121 first strikes the inner wall of the reflector cup 10, where the cup wall 13 converts the large-angle scattered light into a parallel beam. The parallel light then enters the focusing lens 20, where it is precisely converged by refraction and finally all incident on the end face of the optical fiber 30, completing the coupling and transmission of the optical signal.

[0029] This invention provides a fiber optic sensor in which the cup wall 13 and the cup bottom 12 of a reflector cup 10 form a closed reflective space, with the cup opening 11 facing the focusing lens 20. This structure ensures that light emitted from the light source 121, regardless of its divergence angle, can be reflected and constrained into parallel light by the cup wall 13, avoiding the problem of large-angle light loss due to exceeding the lens's receiving range in traditional single-lens designs, thus maximizing the energy collection of the light source 121. The parallel light, after passing through the focusing lens 20, is fully focused on the end face of the optical fiber 30, significantly improving coupling efficiency. This high coupling efficiency significantly enhances the intensity of the optical signal transmitted through the optical fiber 30, supporting signal transmission over longer distances under the same attenuation conditions, solving the problem of limited detection distance caused by insufficient light energy in traditional sensors. The reflector cup 10, focusing lens 20, and optical fiber 30 are integrated into the same housing, with the reflector cup 10 and focusing lens 20 arranged coaxially, eliminating the need for additional installation space. Compared to the traditional approach of increasing lens size to improve focusing ability, this structure maintains the sensor's miniaturization while improving performance, making it suitable for installation in confined spaces.

[0030] As a further improvement of this utility model, the cup wall 13 is a parabola, and the cup bottom 12 is connected to the focal plane of the parabola. By designing the cup wall 13 of the reflective cup 10 as a parabola and precisely connecting the cup bottom 12 to the focal plane of the parabola, a more optically targeted light path guiding structure is formed. The cup wall 13 adopts a parabola shape, and its curved contour conforms to the optical characteristics of a parabola. All light rays parallel to the axis of the parabola will converge precisely at the focal point of the parabola after reflection. Conversely, if the light source 121 is located at the focal point, any light rays emitted from it at any angle can be converted into beams parallel to the axis after reflection by the parabola. Since the cup bottom 12 is connected to the focal plane of the parabola, and the light source 121 is fixed to the cup bottom 12, the light source 121 can be precisely placed at the focal position of the parabola. When the light source 121 generates large-angle diverging light, any point on the parabolic cup wall 13 will be reflected by the parabolic surface and emitted in a direction parallel to the sensor's optical axis, forming a highly regular parallel beam. This lays the foundation for the efficient focusing of the subsequent focusing lens 20. Compared to the non-parabolic cup wall 13, the parabolic surface has a precise optical correspondence between the focal point and the parallel light, and the fixed connection between the cup bottom 12 and the focal plane ensures that the light source 121 is always in the optimal reflection position, avoiding divergence of reflected light caused by the offset of the light source 121. The parallel light formed by parabolic reflection has a beam direction strictly parallel to the optical axis, without additional deflection or scattering; and the cross-sectional size of the parallel light beam is consistent with the size of the cup opening 11, enabling precise matching with the focusing lens 20.

[0031] As a further improvement of this utility model, the parabolic equation of the parabolic surface of the cup wall 13 is: ρ=2f / (1+cosα), where ρ is the polar radius, f is the focal length, and α is the angle between the parabola and the axis of symmetry. Preferably, the focal length f=0.8mm. The parabolic cup wall 13 designed with this equation reflects parallel light with extremely low angular deviation, and the beam parallelism is much higher than that of non-standard parabolic structures. When this high-quality parallel light is incident on the focusing lens 20, the influence of lens aberrations can be minimized, resulting in a smaller focused spot and more concentrated energy, further improving the optical signal coupling density at the end face of the optical fiber 30. Through mathematical equation constraints, the errors in surface accuracy and focal length parameters of the reflective cup 10 produced in different batches can be controlled within the micrometer level, avoiding individual differences caused by manual grinding or experience-based molds. This consistency ensures that the mass-produced sensors maintain stability in key indicators such as coupling efficiency and detection distance, reducing the application risks caused by product performance fluctuations.

[0032] As a further improvement of this utility model, the focusing lens 20 includes an entrance surface 21 and an exit surface 22. The entrance surface 21 is a plane, and the exit surface 22 is a convex surface. After parallel light is emitted from the reflector cup 10, it first enters the plane entrance surface 21 of the focusing lens 20 perpendicularly. According to the law of refraction, when the light is perpendicular to the incident plane, both the angle of refraction and the angle of incidence are 0°, and the light can enter the lens without deflection, avoiding light deviation caused by changes in the angle of incidence. This design ensures that all parallel light output from the reflector cup 10 can enter the lens in a regular posture, providing a stable incident basis for subsequent focusing. When the parallel light entering the lens reaches the convex exit surface 22, due to the curvature characteristics of the convex surface, the light will be refracted in the direction of the lens optical axis. The convex surface allows parallel light incident at different positions to converge precisely at the focal point of the lens after refraction, thereby achieving efficient conversion from parallel light to converging light. The planar light-inlet surface 21 eliminates the deflection loss when light is incident, while the convex light-outlet surface 22 achieves precise convergence of light across the entire aperture through curvature optimization.

[0033] Compared to traditional designs such as double-convex or flat concave surfaces, planar light intake avoids edge light escape problems caused by oblique light incidence, allowing as much parallel light output from the reflector cup 10 as possible to enter the effective optical path of the lens. Convex light output, through refraction control of a single curved surface, reduces reflection loss that may occur in multi-curved designs, improves lens transmission efficiency, and enhances the intensity of the optical signal received by the fiber optic cable 30. The asymmetric surface type can specifically correct spherical aberration, planar light intake reduces differences in the angle of light incidence, and convex light output compensates for refraction deviations of light at different heights through curvature design. The planar light intake surface 21 can serve as a reference surface for optical alignment, and its parallelism with the cup opening 11 of the reflector cup 10 is easily ensured through machining. During assembly, only ensuring the parallelism between the planar light intake surface 21 and the cup opening 11 of the reflector cup 10 is required to guarantee optical path coaxiality, significantly reducing assembly precision requirements. At the same time, the planar structure is more resistant to mechanical shock than curved surfaces, and is less prone to optical path deviation due to deformation in vibration environments, improving the long-term working stability of the sensor in industrial scenarios.

[0034] As a further improvement of this utility model, the diameter of the cup opening 11 is equal to the diameter of the light-receiving surface 21. Preferably, the diameter of the cup opening 11 is 2R = 3.8 mm, and the ratio of the radius of the cup opening 11 to the depth of the reflector cup 10 is R / H = 0.67. The cup opening 11 of the reflector cup 10 is the output port of parallel light, and its diameter determines the size of the beam cross-section of the parallel light. The light-receiving surface 21 of the focusing lens 20 is the receiving port of parallel light, and its diameter determines the maximum range of light that the lens can receive. When the diameters of the two are equal, the cross-section of the parallel light beam output by the reflector cup 10 can be perfectly matched with the light-receiving surface 21, and the parallel light can cover the entire effective receiving area of ​​the light-receiving surface 21 without overflow or gaps, avoiding optical path interruption caused by size mismatch. During assembly, equal diameters can serve as a visual reference for mechanical alignment. By calibrating the overlap between the edge of the cup 11 and the edge of the light-entry surface 21, it is possible to quickly confirm whether the reflector cup 10 and the focusing lens 20 are strictly aligned along the optical axis, reducing the deflection or loss of parallel light caused by component offset, and providing structural support for a stable optical path.

[0035] If the diameter of the cup opening 11 is larger than the diameter of the light-receiving surface 21, some of the parallel light output from the reflector cup 10 will not be received because it exceeds the range of the light-receiving surface 21, causing edge light to escape. If the diameter of the cup opening 11 is smaller than the diameter of the light-receiving surface 21, there will be blank areas on the light-receiving surface 21 that are not covered by parallel light, wasting the effective receiving area of ​​the lens, both of which will lead to light energy loss. When the diameters of the cup opening 11 and the light-receiving surface 21 are equal, all the parallel light output from the reflector cup 10 can be completely incident on the light-receiving surface 21 of the focusing lens 20, without any edge light leakage or wasted area of ​​the light-receiving surface 21, thus improving the light energy receiving efficiency and directly providing an energy basis for optimizing the coupling efficiency of the fiber optic 30. When the diameters of the cup opening 11 and the light-receiving surface 21 do not match, if there is a slight assembly deviation, the center of the parallel light will be misaligned with the center of the light-receiving surface 21, causing the light to enter the lens edge at an angle, triggering additional refraction and deflection, and destroying the concentration of the focused spot. When the diameters are equal, the matching between the beam cross section and the light-receiving surface 21 is stronger, and even if there is a slight deviation, it can ensure that most of the light enters the effective area of ​​the lens perpendicularly.

[0036] As a further improvement of this utility model, the end face of the optical fiber 30 is located on the focal plane of the focusing lens 20. According to the principles of geometric optics, the focusing lens 20 has a converging effect on incident light parallel to the optical axis. All parallel incident light rays, after refraction by the lens, will converge precisely at the focal point of the lens. The focal plane is the core reference plane for the optical performance of the lens, and its position is determined by the focal length of the lens. Setting the end face of the optical fiber 30 on the focal plane means that the end face of the optical fiber 30 completely coincides with the convergence point of parallel light of the focusing lens 20. When the parallel light output from the reflector cup 10 enters the focusing lens 20, the converged light formed by the lens refraction will be focused entirely on the end face of the optical fiber 30, avoiding the focus point shift caused by the end face deviating from the focal plane, and ensuring that the light energy is accurately injected into the optical fiber 30. The position of the focal plane is determined by the inherent parameters of the focusing lens 20, eliminating the need to repeatedly adjust the position of the optical fiber 30 to find the optimal receiving point; during assembly, it is only necessary to determine the position of the focal plane according to the focal length of the lens and fix the end face of the optical fiber 30 in that position, reducing the trial-and-error process that relies on real-time detection by an optical power meter.

[0037] As a further improvement of this utility model, the light source 121 is located at the center of the cup bottom 12. The center of the cup bottom 12 coincides exactly with the optical axis. Placing the light source 121 at the center of the cup bottom 12 ensures that the light source 121 falls precisely at the focal point of the parabola, ensuring that the light emitted by the light source 121 is symmetrically distributed along the optical axis and forms a regular parallel beam after reflection by the cup wall 13. Inside the sensor, the reflector cup 10, focusing lens 20, and optical fiber 30 are arranged sequentially along the optical axis, and the center of the cup bottom 12 is the only reference point of the optical axis at the end of the reflector cup 10. Fixing the light source 121 at this position ensures that the initial emission direction of the light is symmetrical about the optical axis, avoiding the reflected light from being deflected to one side due to the offset of the light source 121, and providing a coaxial optical path basis for the subsequent parallel light to enter the focusing lens 20 and finally converge at the end face of the optical fiber 30. The distance from the center of the cup bottom 12 to all points on the cup wall 13 is equal. When the light source 121 is placed at this location, the emitted light can cover the entire area of ​​the cup wall 13 with the same incident angle. If the light source 121 is off-center, the cup wall 13 on the side closer to the light source 121 will receive too much light, while the side farther away will form a reflection dead angle due to the small incident angle, resulting in some areas of the cup wall 13 not participating in light reflection. The center of the cup bottom 12 can be machined to form a clear positioning reference, such as a circular groove or a center scale. During assembly, it is only necessary to align the center of the light source 121 with the center reference of the cup bottom 12 to complete the precise fixation, without the need for repeated adjustments of the position of the light source 121 through optical detection.

[0038] As a further improvement of this utility model, the light source 121 is disposed on the cup bottom 12 in either a surface mount package or a through-hole package. In a surface mount package, the light source 121 chip is directly soldered onto a pre-set metal pad on the cup bottom 12 using solder paste. This results in a thinner package structure, and the light-emitting center of the light source 121 chip can be precisely aligned with the center of the cup bottom 12. Utilizing the high-precision positioning characteristics of surface mount technology, optical alignment between the light source 121 and the reflector cup 10 is achieved, while simultaneously meeting the space requirements for sensor miniaturization. In a through-hole package, the light source 121 pins are inserted into pre-set pin holes on the cup bottom 12 and fixed by soldering to form a mechanical and electrical connection. This package structure has strong vibration resistance, and the pins can serve as heat dissipation pathways to assist in heat dissipation of the light source 121. The principle is to ensure that the relative position of the light source 121 with the focal point of the reflector cup 10 remains stable even under harsh operating conditions, while also considering heat dissipation and ease of assembly. Surface mount packaging is compatible with automated production lines, enabling high-speed, high-precision batch mounting of the 121 light source using a pick-and-place machine, suitable for large-scale mass production. Through-hole packaging is compatible with traditional through-hole processes, eliminating the need for complex surface mount equipment, and is suitable for small-batch customization or manual assembly scenarios. Both packaging methods cover the entire production process from large-scale mass production to small-batch customization. With surface mount packaging, a single production line can achieve higher daily capacity; with through-hole packaging, production can be started without modifying existing through-hole equipment, reducing equipment investment costs and meeting the needs of different production scales.

[0039] As a further improvement of this utility model, the light source 121 is an LED light source 121. LEDs are semiconductor light-emitting devices, with a typical emission angle between 60° and 180°, exhibiting a large-angle divergence characteristic, which perfectly matches the design requirement of the reflector cup 10 to gather large-angle light. When the LED is working, the divergent light emitted can fully cover the cup wall 13 area of ​​the reflector cup 10, and after parabolic reflection, it is converted into parallel light, perfectly matching the optical path structure of the reflector cup 10 and the focusing lens 20. LEDs have high electro-optical conversion efficiency, producing stronger light output under the same electrical power, and their emission wavelength is stable, which can match the low-loss window of the optical fiber 30, reducing the attenuation of the optical signal during transmission in the optical fiber 30.

[0040] As a further improvement of this utility model, the reflector cup 10 is provided with an aluminum-plated layer. The aluminum-plated layer on the inner wall of the reflector cup 10 utilizes the high reflectivity and stable chemical properties of aluminum to enhance light reflection efficiency and ensure long-term stability. Aluminum has a high reflectivity in the visible to near-infrared band. When light emitted from the light source 121 strikes the aluminum-plated layer, most of the light is reflected, maximizing the retention of light energy and ensuring the efficient conversion of divergent light to parallel light by the reflector cup 10. Preferably, a protective film, such as an oxide film or organic coating, is superimposed on the aluminum-plated layer to prevent oxidation and corrosion of the aluminum layer by oxygen and moisture in the air, while also preventing dust adhesion from affecting the reflection effect and ensuring that the reflectivity does not significantly decrease during long-term use.

[0041] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0042] The above embodiments only illustrate preferred implementations of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. An optical fiber sensor, characterized in that, Includes a housing, a reflecting cup, a focusing lens, and an optical fiber disposed within the housing; The reflective cup includes a cup mouth, a cup bottom, and a cup wall connecting the cup mouth and the cup bottom. The cup mouth is positioned facing the focusing lens, and a light source is provided at the cup bottom. The reflector cup, the light source, the focusing lens, and the optical fiber are arranged sequentially along the optical axis. The light source is used to generate light, which is reflected by the reflector cup to form parallel light; the focusing lens converges the parallel light to the end face of the optical fiber.

2. The fiber optic sensor according to claim 1, characterized in that, The cup wall is a parabola, and the bottom of the cup is connected to the focal plane of the parabola.

3. The fiber optic sensor according to claim 2, characterized in that, The equation of the parabola of the cup wall is: ρ=2f / (1+cosα), where ρ is the polar radius, f is the focal length, and α is the angle between the parabola and the axis of symmetry.

4. The fiber optic sensor according to claim 1, characterized in that, The focusing lens includes an input surface and an output surface, wherein the input surface is a plane and the output surface is a convex surface.

5. The fiber optic sensor according to claim 4, characterized in that, The diameter of the cup opening is equal to the diameter of the light-gathering surface.

6. The fiber optic sensor according to claim 1, characterized in that, The end face of the optical fiber is located on the focal plane of the focusing lens.

7. The fiber optic sensor according to claim 1, characterized in that, The light source is located at the center of the bottom of the cup.

8. The fiber optic sensor according to claim 7, characterized in that, The light source is mounted on the bottom of the cup using either a surface-mount or plug-in packaging method.

9. The fiber optic sensor according to claim 1, characterized in that, The light source is an LED light source.

10. The fiber optic sensor according to claim 1, characterized in that, The reflector cup has an aluminum plating layer inside.

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