Optical system and device for high-precision detection

Abstract

The invention provides an optical system and device for high-precision detection, the lens design has telecentric optical path design, the influence of large near and small far and blind area caused by the field angle of the traditional microscope lens is avoided, the detection problem of lens depth-of-field adaptation is improved by the design of the variable aperture, and the variable spectrum design of the point light and the combined ring light can improve the detection accuracy of the lens depth-of-field adaptation. The system has R / G / B / W waveband switching, can be compatible with main application requirements of current high-precision visible light detection, has bright field, dark field and backlight design in a light source irradiation scheme, has irradiation capability of different angles and wavebands of high, middle, low and bottom, and can be compatible with most defect detection scenes. The independent automatic focusing device supports switching of different products to achieve the rapid focusing capacity, namely, real-time automatic focusing is achieved through the line laser triangulation method, the problem of product warping or poor platform flatness is effectively solved, and the optical system is compact in overall design and suitable for ultra-high-speed and high-precision detection scenes which cannot be compatible with a traditional detection system.

Description

Technical Field

[0001] The present invention relates to the technical field of optical systems, and in particular to an optical system and device for high-precision detection. Background Art

[0002] The current traditional high-precision detection solution is mainly to shoot through a microscope device combined with bright and dark field light sources, but this solution has technical limitations. The reason is that the microscope is small in size and cannot support the size of the camera photosensitive chip with a large target surface. Therefore, the detection efficiency cannot be effectively improved. In addition, the microscope has a field of view problem and cannot avoid the image problem of near large and far small caused by the field of view and the field of view blind spot problem with height difference. In addition, bright and dark field lighting can solve the defects on the surface of the object being measured, but the detection effect for transparent objects or edge chipping is not as good as backlit images, so there will be missed detection problems. Summary of the invention

[0003] In view of the defects in the prior art, an object of the present invention is to provide an optical system and device for high-precision detection.

[0004] The optical system for high-precision detection provided by the present invention comprises: a camera, a lens, a variable point light source, a first fixing member, a second fixing member, an aperture adjustment device, a laser receiving camera, a laser transmitter, a variable combination light group, an object to be tested and a bottom backlight source;

[0005] The camera and lens are connected using threads;

[0006] The variable point light source is fixed on the lens through a first fixing member;

[0007] The lens is designed with a variable aperture, and the aperture is changed through the aperture adjustment device. After the adjustment is completed, it is fixed and locked by the second fixing part;

[0008] The laser transmitter and laser receiving camera are installed below the lens and above the variable combination light group, and are installed symmetrically to each other; when different detection products are switched, the laser transmitter emits laser, which is received by the laser receiving camera to calculate the height position of the product;

[0009] The object to be tested is placed on the testing platform, and the bottom backlight is embedded inside the platform, moving with the platform for shooting.

[0010] Preferably, the variable point light source realizes R / G / B / W four-color switching to provide bright field illumination for the imaging system;

[0011] The variable combination light group can realize R / G / B / W four-color switching to provide dark field illumination for the imaging system;

[0012] The bottom backlight source provides backlight illumination for the imaging system;

[0013] Combining variable point light sources, variable combination light groups and bottom backlight sources, full coverage of high, medium, low and bottom illumination angles is achieved.

[0014] Preferably, heat is dissipated for the variable point light source by a heat dissipation device;

[0015] The heat dissipation device is arranged just above the lamp bead of the variable point light source and close to the position of the lamp bead for heat conduction and heat dissipation, and the air flow through the gap in the middle of the heat dissipation device takes away the heat.

[0016] Preferably, the variable point light source comprises a plurality of sub-variable point light sources;

[0017] The light from each sub-variable point light source is totally reflected by the corresponding third beam splitter, and then collimated and focused by multiple lenses before being irradiated onto the object to be tested;

[0018] The sub-variable point light source is designed with variable bands, including red light sources, green light sources, blue light sources and white light sources. The R / G / B / W illumination requirements are achieved by switching four types of lamp beads.

[0019] Preferably, the variable combination lamp group is a four-layer ring light combination, which is installed directly below the lens. The four-layer ring light combination increases in size and irradiation angle layer by layer from top to bottom. Each layer is connected by a light source shell with an outer mold, and each layer of lamp beads is adhered to the shell through a PCB board;

[0020] The variable combination lamp group includes a red lamp group, a green lamp group, a blue lamp group and a white lamp group. Each group of lamp beads selects lamp beads with different emitting angles according to needs, and the irradiation angle is 0°~90°. The R / G / B / W irradiation needs are achieved through different levels of selection and switching.

[0021] Preferably, a CCD photosensitive chip is provided on the camera to convert the light signal into a digital signal and output the captured image.

[0022] Preferably, the lens comprises three parts;

[0023] The first part includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens. Each layer of lenses is installed layer by layer from bottom to top. Each layer of lenses is connected and fixed to the lens outer shell by glue. The inner part of the lens outer shell is processed to reserve the lens installation position;

[0024] The second part includes a variable aperture and a first beam splitter and a second beam splitter, which are fixed inside the housing by glue, wherein the first beam splitter and the second beam splitter are installed correspondingly on the left and right, and the housing is fixed by screws;

[0025] The third part includes the sixth lens, the seventh lens, the eighth lens and the ninth lens, each layer of lenses is installed layer by layer from top to bottom, and each layer of lenses is connected and fixed to the outer shell of the lens by glue;

[0026] The first part, the second part and the third part of the lens are connected and fixed by a thread structure;

[0027] The first beam splitter is a 1 / 2 beam splitting design, which shares the light from the side and the upper and lower directions; the second beam splitter is a full-reflection mirror, which reflects the point light through the lens to reach the object to be measured.

[0028] Preferably, the variable iris realizes the change of different apertures to adapt to the depth of field requirements in different detection scenes. The depth of field corresponding to different apertures is:

[0029]

[0030]

[0031]

[0032] Among them, δ is the diameter of the circle of confusion; f is the focal length of the lens; F is the lens aperture; L is the focus distance; ΔL1 is the front depth of field; ΔL2 is the back depth of field; ΔL is the depth of field;

[0033] When the focal length f of the lens, the diameter of the circle of confusion δ, and the focusing distance L are constant, the depth of field is approximately inversely proportional to the aperture, that is, the larger the aperture, the smaller the depth of field.

[0034] Preferably, an automatic focusing device is added to the optical system to achieve automatic focusing when adapting to different products or switching materials. The automatic focusing device uses an oblique laser triangulation method to ensure that the image plane receives more contour feature information;

[0035] The expression of the measured object is:

[0036]

[0037]

[0038]

[0039] Among them, θ is the angle between the lens optical axis and the normal line of the object being measured; is the angle between the incident laser axis and the normal line of the object being measured; l is the object distance; α is the angle between the emitted light path due to the height change of the object being measured; β is the angle between the center line of the imaging optical axis and the CCD photosensitive chip; x is the displacement change of the image point of the object being measured; h is the height of the object being measured; the angle between the lens optical axis and the normal line of the object being measured, θ, is equal to the angle between the incident laser axis and the normal line of the object being measured

[0040] Object distance l, focal length f, angle θ, β, When all are quantitative, the height h is obtained by the value of the image point displacement change x, so the lens automatically adjusts the focus based on the measured h value.

[0041] The device for high-precision detection provided by the present invention comprises the optical system for high-precision detection.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) The optical system is designed with a telecentric optical path, which is mainly designed to support large-target cameras. It can support up to 150 million pixel array or 16K linear array cameras, solving the pain point that the current traditional microscope optical system only supports small-target 2500W array or 4K linear array cameras with low detection efficiency. Therefore, the detection efficiency of this optical system can be improved by about 3-4 times compared with the traditional microscope detection system;

[0044] (2) By adopting a telecentric lens design, the parallax problem of traditional lenses is corrected. It can keep the image magnification unchanged within a certain object distance range, solving the problem of other lenses with a field of view that images are larger near and smaller far away, as well as the blind spot problem caused by the field of view. At the same time, the variable aperture design can also solve the pain point that the depth of field of the microscope cannot be changed.

[0045] (3) The multi-band spot light and combined light group design further improves the compatibility with different product inspection requirements. By combining high, medium, and low angles and bottom illumination, more images can be obtained, and inspections are more accurate. This also solves the pain point of missed inspections of transparent products in traditional inspection solutions when only bright and dark field lighting is used for image taking.

[0046] (4) By adding an automatic focusing device, a faster focusing adjustment method is provided for product switching or production change. This solution solves the common problems of high lens design cost and poor lens resolution in traditional coaxial focusing solutions through the oblique axis design of the laser triangulation method. In addition, this solution can also have higher focusing accuracy, which is very suitable for scenarios where focusing is difficult due to product tilting or uneven platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0048] Figure 1 It is the detection flow chart;

[0049] Figure 2 Specific shooting flow chart for optics;

[0050] Figure 3 It is the overall optical system structure diagram;

[0051] Figure 4a and Figure 4b A specific design scheme for a variable point light source;

[0052] Figure 5 The specific design of the variable combination lamp group;

[0053] Figure 6 Designed for telecentric lenses;

[0054] Figure 7a Schematic diagram of the depth of field corresponding to different apertures; Figure 7b is the schematic diagram;

[0055] Figure 8 This is the principle diagram of the automatic focusing device;

[0056] In the figure:

[0057] 101- camera 201- CCD photosensitive chip 300- heat dissipation device

[0058] 102-lens 202-first lens 301-third beam splitter

[0059] 103-variable point light source 203-second lens 302-sub-variable point light source

[0060] 104-first fixing member 204-third lens 302R-red light source

[0061] 105- second fixing member 205- fourth lens 302G- green light source

[0062] 106-aperture adjustment device 206-fifth lens 302B-blue light source

[0063] 107-Laser receiving camera 207-Variable aperture 302W-White light source

[0064] 108-laser transmitter 208-first beam splitter 303-tenth lens

[0065] 109- variable combination lamp group 209- sixth lens 304- eleventh lens

[0066] 109R- red light group 210- seventh lens 305- twelfth lens

[0067] 109G- green light group 211- eighth lens

[0068] 109B- blue light group 212- ninth lens

[0069] 109W-white light group 213-second beam splitter

[0070] 110-Test object

[0071] 111-Bottom backlight DETAILED DESCRIPTION

[0072] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0073] Example

[0074] The present invention provides an optical system design for high-precision detection, and the specific scheme is as follows:

[0075] Testing process such as Figure 1 As shown;

[0076] Step 1: After the product is loaded onto the testing platform, the product is sucked flat;

[0077] Step 2: The laser distance measuring device measures the product and guides the detection system to focus;

[0078] Step 3: The detection system scans and takes pictures according to the material shooting points;

[0079] Step 4: The image is transmitted to the software system for processing, and the detection results of each shooting point are output;

[0080] Step 5: Comprehensively analyze the inspection results of all inspection points of the material and output the overall inspection Map data.

[0081] The specific optical shooting process is as follows Figure 2 As shown;

[0082] Step 1, obtaining the first point light image, which is a detection image under bright field illumination;

[0083] Step 2: Identify surface defects based on the point light image and record the defect location and type;

[0084] Step 3, obtaining a second ring light image, which is a detection image under dark field illumination;

[0085] Step 4: Identify surface foreign matter and record defect location and type based on the ring light image;

[0086] Step 5, obtaining a third backlit image, which is a bottom-lit image;

[0087] Step six: Identify defects such as cracks, breakage, and edge chipping of the material based on the backlight image, and record the location and type of the defect.

[0088] The overall optical system Figure 3 As shown, the large target area camera 101 and the coaxial telecentric lens 102 are connected by threads, and the variable point light source 103 is fixed on the telecentric lens 102 through the first fixing member 104 to provide bright field illumination for the imaging system, wherein the point light source 103 can realize R / G / B / W four-color switching. The telecentric lens 102 is designed with a variable aperture, and the aperture is changed by the aperture adjustment device 106. After the adjustment is completed, it can be fixed and locked by the second fixing member 105. Therefore, the second fixing member 105 is a locking screw on the lens, and 106 is an aperture adjustment device. The F value of the aperture is adjusted by rotation, that is, the aperture is adjusted to control the optimal light transmission. When switching for different inspection products, the optical system also adds an automatic focusing device design, that is, the laser is emitted by the laser transmitter 108, and the laser receiving camera 107 receives and calculates the product height position. Therefore, the laser transmitter 108 and the laser receiving camera 107 are installed below the lens 102 and above the variable combination light group 109, and are installed symmetrically with each other. The laser emission and reception are symmetrical angles, that is, the corresponding center normal angles are consistent. The automatic focusing device guides the telecentric lens 102 to focus quickly. The variable combination light group 109 is installed directly below the lens and the automatic focusing device, and is installed with the same axis as the lens and the automatic focusing device. It mainly provides dark field illumination for the imaging system, and the combination light group 109 can also realize R / G / B / W four-color switching to be compatible with the detection requirements of different products. The object to be tested 110 is mainly a product for high-precision detection. The backlight is a bottom backlight source 111, which provides a backlight illumination image for the imaging system. Therefore, the object to be tested 110 is set up on the detection platform, and the backlight source is embedded in the platform, and moves with the platform to shoot. This solution combines the variable point light source 103, the variable combination light group 109 and the bottom backlight source 111 to achieve full coverage of high, medium, low and bottom illumination angles.

[0089] The specific design scheme of the variable point light source 103 is as follows: Figure 4a and Figure 4bAs shown, after the brightness of the point light source is increased, the luminous power is relatively large, wherein the heat sink 300 is used to dissipate heat for the point light source, wherein the heat sink is directly above the lamp bead and close to the position of the lamp bead for heat conduction and heat dissipation, and the air flow through the gap in the heat sink takes away the heat, and each lamp bead is in a flashing light mode, and the heat is not high. The light of each sub-variable point light source 302 is fully reflected by the corresponding third beam splitter 301, and after being collimated and focused by the tenth lens 303, the eleventh lens 304 and the twelfth lens 305, it is irradiated to the object to be measured. The point light is designed as a variable band design, 302R is a red light source, 302G is a green light source, 302B is a blue light source, and 302W is a white light source. The irradiation requirements of R / G / B / W are achieved by switching the four lamp beads.

[0090] The specific design of the variable combination lamp group 109 is as follows Figure 5 As shown, the light source is designed as a four-layer ring light combination, which is installed just below the telecentric lens. The four layers of light sources increase in size and irradiation angle from top to bottom. Each layer is connected by a light source shell with an outer mold, and no reinforcement device is required, that is, it can be molded in an integrated manner. Each layer of lamp beads is adhered to the shell through a PCB board. 109R is a red light group, 109G is a green light group, 109B is a blue light group, and 109W is a white light group. Each group of lamp beads can choose lamp beads with different luminous angles according to needs, and the irradiation angle is between 0° and 90°. The light source also realizes the irradiation requirements of R / G / B / W by switching at different levels. Since the variable combination lamp group 109 itself has a large heat dissipation space, there is no need to design a heat dissipation device separately.

[0091] The telecentric lens 102 is designed as follows Figure 6As shown, the CCD photosensitive chip 201 receives the light signal, converts the light signal into a digital signal and outputs the captured image, and the overall optical path is composed of the first lens 202, the second lens 203, the third lens 204, the fourth lens 205, the fifth lens 206, the variable aperture 207, the first beam splitter 208, the sixth lens 209, the seventh lens 210, the eighth lens 211, the ninth lens 212 and the second beam splitter 213. Among them, 201 is a CCD photosensitive chip, which is on the camera, and the camera is connected to the lens 102 by a threaded structure. The lenses between the first part 202 to 206 of the lens are installed layer by layer from bottom to top, and each layer of lenses is connected and fixed to the outer shell of the lens by glue, and the inner shell of the outer shell of the lens is processed to reserve the lens installation position; the second part is composed of the variable aperture 207 and the first beam splitter 208 and the second beam splitter 213, which are also fixed inside the shell by glue, wherein the first beam splitter 208 and the second beam splitter 213 are installed in left and right correspondence, and the shell is fixed by screws. The third part is composed of lenses 209-212. Each layer of lenses is installed layer by layer from top to bottom, and each layer of lenses is connected and fixed to the outer shell of the lens with glue. The first part, the second part and the third part of the lens are connected and fixed by a threaded structure. The first beam splitter 208 is a 1 / 2 beam splitting design, which mainly shares the light from the side and the upper and lower directions; the second beam splitter 213 is a full-reflection mirror, which mainly reflects point light through the lens to reach the object to be measured; because the lens is composed of multiple lenses, the optical center of each lens must be on the same straight line, so that the image can be clearer and sharper. The variable aperture 207 can achieve different aperture changes. This design is to adapt to the depth of field requirements in different detection scenarios; such as Figure 7a As shown, the depth of field corresponding to different apertures is also different. The specific principle is as follows Figure 7b As shown, according to the depth of field formula:

[0092]

[0093]

[0094]

[0095] Among them, δ is the diameter of the circle of confusion; f is the focal length of the lens; F is the lens aperture; L is the focus distance; ΔL1 is the front depth of field; ΔL2 is the back depth of field; ΔL is the depth of field;

[0096] In summary, when the focal length f, the diameter of the circle of confusion δ, and the focusing distance L of the lens are constant, the depth of field is approximately inversely proportional to the aperture, that is, the larger the aperture, the smaller the depth of field (the larger the aperture, the smaller the F value, the more light enters, the larger the effective aperture, and the smaller the depth of field).

[0097] An automatic focusing device is added to the optical system, which is mainly designed to achieve automatic focusing when adapting to different products or switching materials. The device uses oblique laser triangulation method, such as Figure 8 As shown in the figure, in order to ensure that the image plane receives more contour feature information, a symmetrical design is made, that is, the angle θ between the lens optical axis and the normal line of the object being measured is equal to the angle between the laser incident optical axis and the normal line of the object being measured. From the sine theorem of △AOB and △COD, we know that:

[0098]

[0099]

[0100]

[0101] Among them, θ is the angle between the lens optical axis and the normal line of the object being measured; is the angle between the incident laser axis and the normal line of the object being measured; l is the object distance; α is the angle between the emission light path when the height of the object being measured changes; β is the angle between the center line of the imaging optical axis and the CCD photosensitive chip; x is the displacement change of the image point of the object being measured; and h is the height of the object being measured.

[0102] In summary, the oblique-injection and oblique-receiving laser triangulation distance measurement method has the following advantages: object distance l, focal length f, angles θ, β, When both are quantitative, the height h can be obtained by the value of the image point displacement change x. Therefore, the lens can adjust the automatic focus according to the measured h value.

[0103] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0104] Those skilled in the art know that, in addition to implementing the system, device and its various modules provided by the present invention in a purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, the system, device and its various modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing the method and structures within the hardware component.

[0105] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. An optical system for high-precision detection, characterized in that: include: A camera (101), a lens (102), a variable point light source (103), a first fixing member (104), a second fixing member (105), an aperture adjustment device (106), a laser receiving camera (107), a laser transmitter (108), a variable combination light group (109), an object to be measured (110), and a bottom backlight source (111); The camera (101) and the lens (102) are connected by threads; The variable point light source (103) is fixed on the lens (102) via a first fixing member (104); The lens (102) is designed with a variable aperture, and the aperture is changed by an aperture adjustment device (106), and is fixed and locked by a second fixing member (105) after the adjustment is completed; The laser transmitter (108) and the laser receiving camera (107) are installed below the lens (102) and above the variable combination light group (109), and are installed symmetrically to each other; when different detection products are switched, the laser transmitter (108) emits laser light, which is received by the laser receiving camera (107) to calculate the height position of the product; The object to be tested (110) is set up on a testing platform, and a bottom backlight source (111) is embedded inside the platform and moves along with the platform for shooting.

2. The optical system for high-precision detection according to claim 1, characterized in that: The variable point light source can realize R / G / B / W four-color switching, providing bright field illumination for the imaging system; The variable combination light group can realize R / G / B / W four-color switching to provide dark field illumination for the imaging system; The bottom backlight source provides backlight illumination for the imaging system; Combining variable point light sources, variable combination light groups and bottom backlight sources, full coverage of high, medium, low and bottom illumination angles is achieved.

3. The optical system for high-precision detection according to claim 1, characterized in that: Dissipate heat for the variable point light source through a heat dissipation device; The heat dissipation device is arranged just above the lamp bead of the variable point light source and close to the position of the lamp bead for heat conduction and heat dissipation, and the air flow through the gap in the middle of the heat dissipation device takes away the heat.

4. The optical system for high-precision detection according to claim 1, characterized in that: The variable point light source includes a plurality of sub-variable point light sources; The light from each sub-variable point light source is totally reflected by the corresponding third beam splitter, and then collimated and focused by multiple lenses before being irradiated onto the object to be tested; The sub-variable point light source is designed with variable bands, including red light sources, green light sources, blue light sources and white light sources. The R / G / B / W illumination requirements are achieved by switching four types of lamp beads.

5. The optical system for high-precision detection according to claim 1, characterized in that: The variable combination lamp group is a four-layer ring light combination, which is installed directly below the lens. The four-layer ring light combination increases in size and irradiation angle from top to bottom. Each layer is connected by a light source shell with an outer mold, and each layer of lamp beads is adhered to the shell through a PCB board; The variable combination lamp group includes a red lamp group, a green lamp group, a blue lamp group and a white lamp group. Each group of lamp beads selects lamp beads with different emitting angles according to needs, and the irradiation angle is 0°~90°. The R / G / B / W irradiation needs are achieved through different levels of selection and switching.

6. The optical system for high-precision detection according to claim 1, characterized in that: A CCD photosensitive chip is set on the camera to convert the light signal into a digital signal and output the captured image.

7. The optical system for high-precision detection according to claim 1, characterized in that: The lens consists of three parts; The first part includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens. Each layer of lenses is installed layer by layer from bottom to top. Each layer of lenses is connected and fixed to the lens outer shell by glue. The inner part of the lens outer shell is processed to reserve the lens installation position; The second part includes a variable aperture and a first beam splitter and a second beam splitter, which are fixed inside the housing by glue, wherein the first beam splitter and the second beam splitter are installed correspondingly on the left and right, and the housing is fixed by screws; The third part includes the sixth lens, the seventh lens, the eighth lens and the ninth lens, each layer of lenses is installed layer by layer from top to bottom, and each layer of lenses is connected and fixed to the outer shell of the lens by glue; The first part, the second part and the third part of the lens are connected and fixed by a thread structure; The first beam splitter is a 1 / 2 beam splitting design, which shares the light from the side and the upper and lower directions; the second beam splitter is a full-reflection mirror, which reflects the point light through the lens to reach the object to be measured.

8. The optical system for high-precision detection according to claim 7, characterized in that: The variable aperture can achieve different aperture changes to adapt to the depth of field requirements in different detection scenarios. The corresponding depth of field under different apertures is: Among them, δ is the diameter of the circle of confusion; f is the focal length of the lens; F is the lens aperture; L is the focus distance; ΔL1 is the front depth of field; ΔL2 is the back depth of field; ΔL is the depth of field; When the focal length f of the lens, the diameter of the circle of confusion δ, and the focusing distance L are constant, the depth of field is approximately inversely proportional to the aperture, that is, the larger the aperture, the smaller the depth of field.

9. The optical system for high-precision detection according to claim 1, characterized in that: An automatic focusing device is added to the optical system to achieve automatic focusing when adapting to different products or switching materials. The automatic focusing device uses oblique laser triangulation to ensure that the image plane receives more contour feature information; The expression of the measured object is: Among them, θ is the angle between the lens optical axis and the normal line of the object being measured; is the angle between the incident laser axis and the normal line of the object being measured; l is the object distance; α is the angle between the emitted light path due to the height change of the object being measured; β is the angle between the center line of the imaging optical axis and the CCD photosensitive chip; x is the displacement change of the image point of the object being measured; h is the height of the object being measured; the angle between the lens optical axis and the normal line of the object being measured, θ, is equal to the angle between the incident laser axis and the normal line of the object being measured Object distance l, focal length f, angle θ, β, When all are quantitative, the height h is obtained by the value of the image point displacement change x, so the lens automatically adjusts the focus based on the measured h value.

10. A device for high-precision detection, characterized in that: An optical system for high-precision detection comprising any one of claims 1 to 9.

Images