A laser triangulation ranging device and system

Abstract

This utility model discloses a laser triangulation ranging device and system; relating to the field of laser ranging technology; including a laser for emitting laser light towards the object being measured; a light-receiving lens assembly for receiving the reflected laser light from the object being measured and correcting and focusing the reflected laser light spot; the light-receiving lens assembly includes a focusing lens and multiple correction elements; the light spot of the reflected laser light from each correction element is corrected in different properties and falls onto the light-receiving element; this solution improves the structure of the traditional laser triangulation ranging optical path by correcting the light spot of the reflected laser light spot in different properties through the light-receiving lens assembly, ensuring measurement accuracy, reducing costs, and effectively accelerating assembly efficiency; by increasing the light spot size in the laser transmission direction at the position of the light-receiving element through the light-receiving lens assembly, the center of the light spot does not need to be aligned with the center of the light-receiving element to be detected, reducing the structural accuracy of the laser triangulation ranging device and improving assembly efficiency.

Description

Technical Field

[0001] This utility model relates to the field of laser ranging technology, specifically to a laser triangulation ranging device and system. Background Technology

[0002] Laser triangulation, a non-contact, high-precision ranging method, has been widely applied in industrial inspection, robot navigation, and 3D scanning. Its basic principle involves projecting a laser beam from a laser emitter onto the object being measured. After reflection from the object's surface, the reflected light forms a spot on the photosensitive chip of a CCD (charge-coupled device) or CMOS image sensor. The distance to the object is then calculated based on the positional offset of this spot on the chip.

[0003] However, the optical path design of existing laser triangulation systems has significant limitations. First, due to the focusing characteristics of the laser beam and the aberrations of the lens components in the optical path, the actual imaging size of the light spot on the photosensitive chip is often larger than the geometric size of a single pixel unit (typically on the order of micrometers). This phenomenon causes the light spot to cover multiple adjacent pixels, reducing the accuracy of the light spot center positioning and thus affecting the accuracy of the ranging results. Second, stray light that is difficult to completely eliminate in the optical path (such as reflections from lens edges and ambient light interference) will superimpose with the effective signal light, further interfering with the shape and grayscale distribution of the light spot and increasing the complexity of the signal extraction algorithm. In addition, during system assembly, it is necessary to ensure that the light spot falls precisely on the preset pixel area of ​​the photosensitive chip. However, since the size of the light spot and the pixel unit are both on the order of micrometers, and there is edge blurring caused by stray light, the position and angle of the optical components need to be repeatedly adjusted during assembly, which places extremely high demands on the stability of the mechanical structure and the precision of the assembly process. This process is not only time-consuming and labor-intensive, but may also damage the device due to repeated calibrations, seriously restricting production efficiency and product yield.

[0004] Existing improvement solutions mostly focus on optimizing lens group design or improving the robustness of image algorithms, but they do not fundamentally solve the negative impact of spot size and pixel mismatch and stray light interference on assembly accuracy. Therefore, there is an urgent need for an innovative optical path design or structural optimization scheme to reduce spot size, suppress stray light, and reduce the difficulty of system assembly and adjustment, thereby improving ranging accuracy and production efficiency. Utility Model Content

[0005] The technical problem this invention aims to solve is that the light spot generated by the traditional laser triangulation optical path is larger than the pixel of the photosensitive chip and also contains stray light. Furthermore, the light spot needs to fall on the pixel of the photosensitive chip, but both the light spot and the pixel of the photosensitive chip are at the micrometer level, resulting in a difficult and inefficient assembly process. The purpose of this invention is to provide a laser triangulation ranging device and system that improves the structure of the traditional laser triangulation optical path by correcting the reflected laser spot for different properties through a light-receiving lens assembly, thereby improving measurement accuracy, reducing costs, and effectively accelerating assembly efficiency.

[0006] This utility model is achieved through the following technical solution:

[0007] This solution provides a laser triangulation ranging device, including:

[0008] A laser is used to emit laser light towards a test object, and the laser light is reflected after reaching the test object.

[0009] A light-receiving lens assembly is used to receive reflected laser light and correct and focus the reflected laser light spot; the light-receiving lens assembly includes a focusing lens and multiple correction elements; each correction element corrects different properties of the reflected laser light spot.

[0010] The light-receiving element is used to collect the reflected laser light after correction and focusing.

[0011] A further optimization scheme is that the correction element includes a spot size correction element and a spot length correction element; the spot size correction element is used to adjust the spot size of the reflected laser; the spot length correction element is used to adjust the size of the reflected laser along the height direction of the light-receiving element.

[0012] A further optimization is that the focusing lens is positioned between the spot size correction element and the spot length correction element, and the spot size correction element receives the reflected laser first.

[0013] A further optimization is that the spot size correction element includes an eccentric aperture stop.

[0014] A further optimization is that the light-receiving element is a photosensitive chip.

[0015] A further optimization scheme is that the eccentric direction of the eccentric aperture stop is determined by the length direction of the photosensitive chip; the eccentric distance of the eccentric aperture stop is determined by the size of the light spot on the photosensitive chip.

[0016] A further optimization is that the spot length correction element includes a cylindrical lens.

[0017] A further optimization scheme is that the radius of curvature of the cylindrical lens is determined by the intensity of the reflected laser spot, the pixel size of the photosensitive chip, and the photosensitivity, and the diameter of the cylindrical lens is determined by the field of view of the light-receiving element with respect to the reflected laser.

[0018] A further optimization scheme includes an output lens, which is disposed on the light-emitting side of the laser.

[0019] This solution also provides a laser triangulation ranging system, including the laser triangulation ranging device described above.

[0020] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0021] 1. The purpose of this utility model is to provide a laser triangulation ranging device and system. Based on the traditional laser triangulation ranging optical path, structural improvements are made. By using a light-receiving lens assembly to correct the light spot of the reflected laser in different properties, the measurement accuracy is improved, the cost is reduced, and the assembly efficiency is effectively accelerated.

[0022] 2. The purpose of this utility model is to provide a laser triangulation ranging device and system. By using a light-receiving lens assembly, the size of the light spot in the length direction on the photosensitive chip surface is reduced, thereby improving the measurement accuracy. At the same time, the size of the light spot in the height direction on the photosensitive chip surface is effectively preserved, ensuring sufficient light energy for subsequent extension of the light spot. The size of the light spot in the height direction of the photosensitive chip at the position of the light-receiving element is increased, so that the center of the light spot does not need to be aligned with the center of the light-receiving element to be detected. This greatly reduces the accuracy requirements of the laser triangulation ranging device structure, reduces costs, and speeds up assembly efficiency.

[0023] 3. The purpose of this utility model is to provide a laser triangulation ranging device and system. By reducing the spot size of the reflected laser along the length of the photosensitive chip through an eccentric aperture, the measurement accuracy is improved. At the same time, the spot size in the height direction on the photosensitive chip surface is effectively preserved, ensuring sufficient light energy for subsequent cylindrical lens extension of the spot. By increasing the spot size of the reflected laser in the laser transmission direction at the position of the light-receiving element through the cylindrical lens, the center of the spot can be detected without being aligned with the center of the light-receiving element. This greatly reduces the structural accuracy of the laser triangulation ranging device, reduces costs, and speeds up assembly efficiency. Attached Figure Description

[0024] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0025] Figure 1 This is a schematic diagram of a laser triangulation ranging device.

[0026] Figure 2 This is a schematic diagram of the principle of a laser triangulation rangefinder.

[0027] Figure 3 A schematic diagram of a laser triangulation rangefinder without an eccentric aperture stop and cylindrical lens.

[0028] Figure 4 A schematic diagram of the light-receiving lens assembly without an eccentric aperture stop;

[0029] Figure 5 A schematic diagram illustrating the light-receiving lens assembly with an added off-center aperture stop and cylindrical lens;

[0030] Figure 6 A schematic diagram illustrating the effect of adding an off-center aperture stop and cylindrical lens to the light-receiving lens assembly on the light-receiving element;

[0031] Figure 7 Schematic diagrams of the light spots without an eccentric aperture stop under different fields of view;

[0032] Figure 8 Schematic diagram of the light spot when adding an off-center aperture stop under different fields of view;

[0033] Figure 9 This is a schematic diagram of the photosensitive chip assembly.

[0034] The attached diagram shows the markings and corresponding component names:

[0035] 1-Laser, 2-Outgoing lens, 3-Near-end test object, 4-Far-end test object, 5-Receiving lens assembly, 51-Window, 52-Focusing lens, 53-Filter, 6-Receiving element, 7-Laser, 8-Eccentric aperture stop, 9-Cylindrical lens. Detailed Implementation

[0036] 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 embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0037] The light spot generated by the traditional laser triangulation optical path is larger than the pixel of the photosensitive chip and also contains stray light. Furthermore, the light spot needs to fall on the pixel of the photosensitive chip, but both the light spot and the pixel of the photosensitive chip are at the micrometer level, which makes the assembly process difficult and inefficient. In view of this, this solution provides the following embodiments to solve the above technical problems.

[0038] Example 1

[0039] This embodiment provides a laser triangulation ranging device, such as... Figure 1 and Figure 2As shown, it includes:

[0040] Laser 1 is used to emit laser 7 towards the test objects (near-end test object 3 and far-end test object 4), and the laser 7 is reflected after reaching the test objects (near-end test object 3 and far-end test object 4).

[0041] The light-receiving lens assembly 5 is used to receive the reflected laser and correct and focus the reflected laser beam; such as Figure 3 and Figure 4 As shown, the light-receiving lens group includes a focusing lens 52 and multiple correction elements; each correction element corrects the light spot of the reflected laser in different aspects.

[0042] The light-receiving element 6 is used to collect the reflected laser light after correction and focusing. The light-receiving element is a photosensitive chip, and the assembly diagram of the photosensitive chip is shown below. Figure 9 As shown.

[0043] The correction element includes a spot size correction element and a spot length correction element; the spot size correction element is used to adjust the spot size of the reflected laser; the spot length correction element is used to adjust the size of the reflected laser along the height direction of the light-receiving element.

[0044] The focusing lens is positioned between the spot size correction element and the spot length correction element, and the spot size correction element receives the reflected laser first.

[0045] The structural diagram of the light-receiving lens assembly 5 without the light spot size correction element and the light spot length correction element is as follows: Figures 3-4 As shown in the figure; on both sides of the focusing lens 52 are the filter 53 and the window 51, and the reflected laser light passes through the window 51, the focusing lens 52 and the filter 53 in sequence before reaching the light receiving element 6;

[0046] Optimized, the spot size correction element includes an eccentric aperture stop 8, such as... Figure 4-6 As shown, the light-receiving lens assembly 5 includes an eccentric aperture stop 8.

[0047] The eccentricity of the eccentric aperture stop is determined by the length direction of the photosensitive chip, and the eccentricity of the eccentric aperture stop is consistent with the length direction of the photosensitive chip; the eccentricity distance of the eccentric aperture stop is determined by the size of the light spot on the photosensitive chip.

[0048] The spot length correction element includes a cylindrical lens 9. Figure 4 The light-receiving lens assembly also includes a cylindrical lens 9, and its light-receiving effect diagram is shown below. Figure 5 As shown in the diagram. Without the cylindrical lens 9, the effect of the light spot on the light-receiving element is illustrated in the diagram. Figure 6As shown in the upper part, the size of the light spot and the height of the light-receiving element are both in the micrometer range. Therefore, accurate alignment presents challenges in terms of structural precision and subsequent assembly and debugging, affecting the final yield and efficiency. A schematic diagram showing the effect of the light spot on the light-receiving element when the cylindrical lens 9 is added is shown below. Figure 6 As shown in the lower part; after changing the optical structure, the size of the light spot in the length direction of the light-receiving element remains unchanged (to ensure measurement accuracy), while the size of the light spot in the height direction of the light-receiving element is increased. In this way, the center of the light spot does not need to be aligned with the center of the light-receiving element to be detected. This greatly reduces the accuracy requirements of the structure, reduces costs, speeds up assembly efficiency, and increases the final yield.

[0049] The radius of curvature of the cylindrical lens 9 is determined by the intensity of the reflected laser spot, the pixel size of the photosensitive chip, and the photosensitive capability, while the diameter of the cylindrical lens is determined by the field of view of the reflected laser on the light-receiving element 6.

[0050] It also includes an output lens 2, which is disposed on the light-emitting side of the laser 1.

[0051] The light-receiving element 6 is a photosensitive chip.

[0052] This embodiment simulates the laser triangulation rangefinder under 1-9 different fields of view. Figure 7 This is a schematic diagram of the laser triangulation rangefinder without an eccentric aperture stop; the spot radii are 17.395μm, 12.417μm, 11.027μm, 10.925μm, 11.513μm, 11.476μm, 12.245μm, 12.086μm and 12.542μm respectively. Figure 8 A schematic diagram of the laser triangulation rangefinder with an eccentric aperture stop is shown, where the spot radii are 11.198μm, 11.3617μm, 7.166μm, 9.588μm, 7.657μm, 10.038μm, 8.666μm, 10.401μm, and 10.122μm, respectively. It can be seen that by using an eccentric aperture stop to correct the spot shape, the spot size along the length direction on the photosensitive chip surface is reduced, thereby improving measurement accuracy. Simultaneously, the spot size along the height direction on the photosensitive chip surface is effectively preserved, ensuring sufficient light energy for subsequent spot extension.

[0053] This invention improves the structure of the traditional laser triangulation optical path by using an eccentric aperture to reduce the spot size of the reflected laser along the length of the photosensitive chip, thereby improving measurement accuracy. Simultaneously, it effectively preserves the spot size in the height direction on the photosensitive chip surface, ensuring sufficient light energy for subsequent cylindrical lens extension of the spot. Furthermore, by using a cylindrical lens to increase the spot size of the reflected laser in the laser transmission direction at the light-receiving element, the center of the spot can be detected even without aligning with the center of the light-receiving element. This significantly reduces the accuracy requirements of the laser triangulation device structure, lowers costs, and accelerates assembly efficiency.

[0054] Example 2

[0055] This embodiment provides a laser triangulation ranging system, including the laser triangulation ranging device described in Embodiment 1.

[0056] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A laser triangulation device, characterized in that include: A laser is used to emit laser light towards a test object, and the laser light is reflected after reaching the test object. A light-receiving lens assembly is used to receive reflected laser light and correct and focus the reflected laser light spot; the light-receiving lens assembly includes a focusing lens and multiple correction elements; each correction element corrects different properties of the reflected laser light spot. The light-receiving element is used to collect the reflected laser light after correction and focusing.

2. The laser triangulation distance measuring device according to claim 1, characterized in that The correction element includes a spot size correction element and a spot length correction element; the spot size correction element is used to adjust the spot size of the reflected laser; the spot length correction element is used to adjust the size of the reflected laser along the height direction of the light-receiving element.

3. The laser triangulation distance measuring device according to claim 2, characterized in that The focusing lens is positioned between the spot size correction element and the spot length correction element, and the spot size correction element receives the reflected laser first.

4. The laser triangulation distance measuring device according to claim 2, wherein, The spot size correction element includes an eccentric aperture stop.

5. The laser triangulation distance measuring device according to claim 4, characterized in that The light-receiving element is a photosensitive chip.

6. The laser triangulation distance measuring device according to claim 5, characterized in that The eccentric direction of the eccentric aperture stop is determined by the length direction of the photosensitive chip; the eccentric distance of the eccentric aperture stop is determined by the size of the light spot on the photosensitive chip.

7. A laser triangulation ranging device according to claim 6, characterized in that, The spot length correction element includes a cylindrical lens.

8. A laser triangulation ranging device according to claim 7, characterized in that, The radius of curvature of the cylindrical lens is determined by the intensity of the reflected laser spot, the pixel size of the photosensitive chip, and the photosensitivity. The diameter of the cylindrical lens is determined by the field of view of the light-receiving element with respect to the reflected laser.

9. A laser triangulation ranging device according to claim 1, characterized in that, It also includes an exit lens, which is disposed on the light-emitting side of the laser.

10. A laser triangulation ranging system, characterized in that, The invention includes a laser triangulation ranging device as described in any one of claims 1-9.

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