Light source, lighting device and detection system
By combining light guide elements and diffusion elements, the problem of insufficient uniformity of detection light is solved, and uniform distribution of detection light on the surface of the object being measured is achieved, which improves detection accuracy and efficiency and is suitable for the detection of minute defects in industries such as semiconductor processing and metal processing.
Patent Information
- Application Number
- CN202520018570.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-03
- Publication Date
- 2026-03-03
- Estimated Expiration
- 2035-01-03
AI Technical Summary
In existing machine vision inspection systems, the uniformity of the detection light is insufficient, making it difficult to meet the inspection needs of industries such as semiconductor processing and metal processing for minute defects on the product surface.
A combination of light guide and diffuser elements is used. The light guide element performs initial homogenization of the detection light, and the diffuser element performs secondary homogenization of the detection light emitted through the light guide element, thereby improving the uniformity of the detection light.
It achieves uniform distribution of detection light on the surface of the object being tested, improving detection accuracy and efficiency, and is especially suitable for detecting minute defects in industries such as semiconductor processing and metal processing.
Smart Images
Figure CN223966443U_ABST
Abstract
Description
[Technical Field]
[0001] This utility model relates to the field of machine vision inspection, and in particular to light sources, lighting devices and inspection systems used in machine vision inspection. [Background Technology]
[0002] Machine vision inspection is widely used in the inspection of industrial products. By displaying the object under test in images, it has the advantage of being faster and more accurate than traditional visual inspection methods.
[0003] The machine vision inspection system includes an illumination device and an image detection device. The illumination device is used to project illumination light onto the object being measured. The illumination light is reflected or scattered by the object being measured and captured by the image detection device, displaying an image of the surface of the object being measured. The object being measured is then detected based on the obtained image.
[0004] Industries such as semiconductor processing, metal processing, and plastic molding have high requirements for the uniformity of detection light to detect minute defects such as micro-cracks and scratches on the product surface. [Utility Model Content]
[0005] The purpose of this invention is to provide a light source, an illumination device, and a detection system that can detect the uniformity of light incident on the surface of the object being tested.
[0006] In a first aspect, this utility model provides a light source, comprising:
[0007] Light-emitting element, used to emit detection light;
[0008] A light guide element includes a light guide portion having an input end and an output end. The input end is used to couple the detection light into the light guide portion, the light guide portion is used to conduct and homogenize the detection light, and the output end is used to couple out the homogenized detection light.
[0009] A diffusion element is disposed on the light-emitting side of the light guide element to diffuse the detection light emitted by the light guide element.
[0010] In some possible implementations, the diffusion element is disposed on the end face of the output end of the light guide element and is in contact with the end face of the output end of the light guide element.
[0011] In some possible implementations, the diffusion element covers the end face of the output end of the light guide element.
[0012] In some possible implementations, the light-emitting element comprises one or more LED chips; or,
[0013] The light-emitting element includes at least two LED chips, and the detection light emitted by the at least two LED chips has different peak wavelengths; or,
[0014] The light-emitting element includes a laser chip and a wavelength conversion element. The laser chip is used to emit excitation light, and the wavelength conversion element is used to convert at least a portion of the excitation light into laser light with different wavelength ranges.
[0015] In some possible implementations, the light guide portion includes a light guide rod.
[0016] In some possible implementations, a coupling element is also included, disposed between the light-emitting element and the light-guiding element, for coupling the detection light into the light-guiding element.
[0017] In some possible implementations, the coupling element includes:
[0018] A collecting lens is used to collect the detection light emitted by the light-emitting element;
[0019] A converging lens is used to converge the detection light into a focused beam.
[0020] In some possible implementations, a telecentric lens is also included, disposed on the light-emitting side of the diffusion element, for guiding the detection light from the diffusion element to the object under test and guiding the detection light returning via the object under test.
[0021] Secondly, this utility model also provides a lighting device, including the light source described above.
[0022] Thirdly, this utility model also provides a detection system, including
[0023] An illumination device for projecting detection light onto a test object, wherein the illumination device includes a light source as described above; and
[0024] The detection device receives detection light returned from the object under test and acquires image information of the object under test based on the detection light.
[0025] The beneficial effects of this utility model are:
[0026] The light source of this invention uses a light guide element to initially homogenize the detection light emitted by the light-emitting element, and then uses a diffusion element to homogenize the detection light emitted through the light guide element again, thereby improving the uniformity of the detection light projected onto the object being measured. [Attached Image Description]
[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:
[0028] Figure 1 This is a schematic illustration of the detection system according to an embodiment of this application.
[0029] Explanation of reference numerals in the attached figures:
[0030] 10. Light-emitting elements;
[0031] 20. Light guide element; 200. Light guide section; 201. Input end; 202. Output end;
[0032] 30. Diffuser element;
[0033] 40. Coupling element; 400. Collecting lens; 401. Converging lens;
[0034] 50. Telecentric lens;
[0035] 60. Image acquisition device;
[0036] 70. The object being measured.
Detailed Implementation Methods
[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.
[0038] Figure 1 A schematic illustration of the detection system according to an embodiment of this application is shown. For example... Figure 1 As shown, the detection system of this application embodiment includes an illumination device and a detection device. The illumination device is used to project detection light onto the object under test 70. At least part of the detection light is incident on the surface of the object under test 70 and is reflected or scattered after passing through the surface of the object under test 70. The detection device is used to acquire the detection light reflected or scattered by the object under test 70, and then acquire image information of the object under test 70 for the purpose of detecting defects in the object under test 70.
[0039] The lighting device includes at least a light source and a carrier (not shown in the figure). The light source is used to generate detection light for detecting the object 70 being measured, and the carrier is used to support and / or seal and / or thermally balance and / or protect the light source. The following section will first combine... Figure 1 The light source described in the embodiments of this application.
[0040] like Figure 1 This application provides a light source, including a light-emitting element 10, a light-guiding element 20, and a diffusion element 30.
[0041] The light-emitting element 10 is used to emit detection light. The detection light is projected onto the object under test 70, and at least part of the detection light is reflected or scattered back by the surface of the object under test 70, thereby being acquired by the detection device to obtain image information of the object under test 70.
[0042] In some embodiments, the light-emitting element 10 can be selected as an LED chip. LED chips have low energy consumption, which helps reduce the operating cost of the system. They have a long service life, generally up to tens of thousands of hours, reducing the number of times the light source needs to be replaced. Furthermore, the light intensity of an LED chip can be adjusted by regulating the current, making it easy to adapt to the lighting requirements of different scenarios. The light-emitting element 10 may include one LED chip or a combination of two or more LED chips. Optionally, the light-emitting element 10 includes at least two LED chips, which may have at least two detection lights with different peak wavelengths. For example, at least two LED chips may emit blue and red detection lights. The blue light has a shorter wavelength, which is suitable for illuminating targets against a silver background and is more effective in detecting defects such as scratches. The red light has a longer wavelength and stronger penetration, which can penetrate relatively dark objects and can be used to detect substances below the surface of an object. It can also highlight the features of the object being tested 70 based on different methods such as color absorption. Of course, in some embodiments, combinations of other wavelength detection lights or combinations of three or more wavelength detection lights may also be used. When the detection light emitted by at least two LED chips has different peak wavelengths, it is also possible to achieve a spectral combination of multiple peak wavelength detection lights, so that the overall detection light appears white.
[0043] In some embodiments, the light-emitting element 10 includes an excitation source and a wavelength conversion element (not shown). The excitation source emits excitation light, which is incident on the wavelength conversion element. The wavelength conversion element has a wavelength conversion material, which converts at least a portion of the incident excitation light into a wavelength range of light. For example, the excitation source emits blue excitation light, and the wavelength conversion element has a yellow fluorescent material. The blue excitation light is incident on the yellow fluorescent material, which converts at least a portion of the blue excitation light into a yellow light. Alternatively, the excitation source can be a laser diode, which emits laser light. Laser light has high energy density and high collimation. The wavelength conversion element converts at least a portion of the laser light into a wavelength range of light, resulting in high brightness and good contrast when illuminating the object 70.
[0044] The light guide element 20 is configured to be made of a transparent or translucent medium such as glass or plastic, having a refractive index greater than that of air. The light guide element 20 can conduct detection light, wherein, as the detection light is conducted within the medium of the light guide element 20, multiple internal reflections occur on the inner wall of the periphery of the light guide element 20, thereby homogenizing the light distribution of the detection light. In some embodiments, the light guide element 20 includes a light guide portion 200 having an input end 201 and an output end 202. The input end 201 is used to couple the detection light into the light guide portion 200, the light guide portion 200 is used to conduct and homogenize the detection light, and the output end 202 is used to couple out the homogenized detection light.
[0045] In some embodiments, the light guide portion 200 includes a light guide rod. The light guide rod is made of a light-transmitting medium, such as glass or plastic, with a refractive index greater than that of air. The detection light emitted by the light-emitting element 10 is coupled into the light guide rod and can propagate within it. On the peripheral side of the light guide rod, the difference in refractive index between the light guide rod and the external air allows for total internal reflection of the detection light during propagation, thereby improving the uniformity of the detection light. The peripheral side of the light guide rod can be made smooth through surface treatment processes such as polishing to suppress the scattering of the detection light caused by minute uneven structures on the peripheral side, reducing leakage of the detection light towards the peripheral side. The light guide rod has an incident surface and an exit surface, which can be made smooth surfaces, for example, obtained through polishing. Smooth incident and exit surfaces can suppress the scattering of the detection light when it enters the light guide rod through the incident surface and exits through the exit surface, thereby improving the utilization efficiency of the detection light. In some optional examples, the light guide can be a cylindrical light guide, and in other optional examples, the light guide can be a square light guide, which can be a square bar, a pentagonal bar, or a similar polygonal bar.
[0046] The diffuser element 30 is disposed on the light-emitting side of the light guide element 20 and is used to diffuse the detection beam emitted through the light guide element 20. The diffuser element 30 is used to homogenize the detection light in a secondary manner, so that the brightness distribution of the light spot on the light-emitting surface of the diffuser element 30 is uniform. Therefore, the detection light can form a relatively uniform light spot when it is projected onto the object under test 70.
[0047] In some embodiments, the diffuser element 30 is disposed on the end face of the output end 202 of the light guide 200 and contacts the end face of the output end 202 of the light guide 200. The diffuser element 30 may be in close contact with the end face of the output end 202 of the light guide 200, so the diffuser element 30 can directly receive the detection light emitted from the output end 202 of the light guide 200. The diffuser element 30 may be configured to cover the end face of the output end 202 of the light guide 200. The shape and size of the diffuser element 30 may be set to be greater than or equal to the shape or size of the output end 202 of the light guide 200. It is understood that the diffuser element 30 covers the end face of the output end 202 of the light guide 200 so that the projection formed on the diffuser element 30 along the light emission direction of the output end of the light guide 200 is located within the area defined by the body of the diffuser element 30, so that the detection light emitted through the output end 202 of the light guide 200 can be received by the diffuser element 30 as much as possible. In some examples, the diffusion element 30 is selected as an angle diffuser, which can be configured to have different diffusion angles for different types of light-emitting elements 10. For example, when the light-emitting element 10 is a monochromatic LED, an angle diffuser with a smaller diffusion angle can be selected, while when the light-emitting element 10 is a white LED, an angle diffuser with a relatively large diffusion angle can be selected. The smaller diffusion angle is selected, for example, from 1 to 5 degrees, and the larger diffusion angle is selected, for example, from 5 to 10 degrees, but this application is not limited thereto.
[0048] The working principle of the lighting device according to the embodiments of this application is described in detail below. During operation, the light-emitting element 10 emits detection light, the light guide element 20 receives the detection light and couples at least a portion of the detection light into the light guide element 20. The light guide element 20 can conduct the detection light, and during the conduction process, the detection light is homogenized by multiple reflections. The diffusion element 30 then homogenizes the detection light after it has been homogenized by the light guide element 20, thereby making the light spot brightness distribution on the light-emitting surface of the diffusion element 30 uniform. When this light spot is projected onto the object 70 being measured, a bright and uniform light spot can be formed.
[0049] The light-emitting element 10 can be configured as a light-emitting unit consisting of at least two LED units, laser units, or laser fluorescence units. It can selectively switch some of the light-emitting units in the at least two light-emitting units to adjust the brightness of the detection light. Alternatively, the at least two light-emitting units can be configured to have different wavelengths to selectively provide one or more wavelengths of detection light.
[0050] Please continue to refer to Figure 1 The lighting device in this embodiment further includes a coupling element 40, which is disposed between the light-emitting element 10 and the light-guiding element 20, and is used to couple the detection light emitted by the light-emitting element 10 into the light-guiding element 20. The coupling element 40 may be configured to include one or more optical lenses for converging the detection light emitted by the light-emitting element 10 into the light-guiding element 20.
[0051] In some embodiments, the coupling element 40 includes a collecting lens 400 and a converging lens 401. The collecting lens 400 is used to collect the detection light emitted by the light-emitting element 10, and the converging lens 401 is used to converge the detection light into a converging light. Figure 1 The collecting lens 400 and the converging lens 401 can be sequentially arranged in the optical path of the detection light emitted by the light-emitting element 10. The collecting lens 400 collects the detection light emitted by the light-emitting element 10 and reduces the divergence angle of the detection light, so that the originally divergent detection light is collimated or nearly collimated. The converging lens 401 is used to converge the detection light into a converging light. The focal point of the converging light in the direction of travel is located at or near the end face of the input end 201 of the light guide 200, for example, slightly in front of or slightly behind the end face, so as to improve the coupling efficiency of the detection light. For example, the detection light emitted by the light-emitting element 10 can have a divergence angle greater than 120 degrees. After being shaped by the collecting lens 400 and the converging lens 401 in sequence, the detection light emitted by the converging lens 401 is shaped into a converging light, and its convergence angle can be less than 50 degrees. Optionally, the convergence angle is, for example, 30 degrees.
[0052] like Figure 1 The lighting device in this application embodiment may further include a telecentric lens 50. The telecentric lens 50 is disposed in the optical path of the detection light emitted from the diffuser element 30, and the telecentric lens 50 is used to guide the detection light from the diffuser element 30 onto the object under test 70.
[0053] In some embodiments, the telecentric lens 50 can be configured to change the direction of travel of the detection light, so that the detection light emitted by the object under test 70 and the self-emissive element 10 has different directions. For example... Figure 1 As shown, the detection light from the diffusion element 30 is... Figure 1 The light is incident on the telecentric lens 50 in a horizontal direction, and the telecentric lens 50 is set to face... Figure 1 The detection light is reflected from below the telecentric lens 50, and the object being measured 70 is positioned below the telecentric lens 50. The telecentric lens 50 can be configured to be tilted relative to the optical axis of the detection light from the diffuser element 30; for example, the telecentric lens 50 can have a 45-degree tilt angle relative to the detection light from the diffuser element 30, reflecting the light from... Figure 1 The detection light in the middle horizontal direction is reflected towards Figure 1 The telecentric lens 50 is positioned on the object 70 being measured, located in the lower center. Of course, the telecentric lens 50 can also be set at other angles, including but not limited to 30 degrees, 60 degrees, etc. Optionally, the telecentric lens 50 can be configured to transmit the detection light reflected or scattered back from the object 70 being measured. The telecentric lens 50 can guide the detection light reflected or scattered back from the object 70 being measured to the detection device to obtain image information of the object 70 being measured. In some other embodiments, the telecentric lens 50 can also be configured to transmit the detection light from the diffusion element 30 and reflect the detection light from the object 70 being measured.
[0054] The embodiments of the light source of this application have been described in detail above. Based on the above embodiments and combinations thereof, this application also provides an illumination device, including the light source as described above. The illumination device is used to project detection light toward the object under test 70. Based on the light source described above, the illumination device of this application embodiment can make the detection light projected onto the object under test 70 form a more uniform light spot.
[0055] Please continue to refer to Figure 1 This application also provides a detection device, including an illumination device and a detection device as described above. The illumination device includes a light source as described above, which projects detection light toward the object under test 70. The detection device receives the detection light returned via the object under test 70 and acquires image information of the object under test 70 based on the detection light. The image information includes, for example, defect information, label information, and appearance information of the object under test 70. In this application embodiment, because the light spot formed on the object under test 70 by the illumination light projected by the illumination device has good uniformity, brightness, and coverage, the image information of the object under test 70 that can be acquired has better contrast, thus improving detection accuracy and efficiency.
[0056] In some embodiments, the detection apparatus includes an image acquisition device 60, which is used to acquire detection light reflected by the object under test 70. For example... Figure 1As shown, in some examples, the image acquisition device 60 and the object under test 70 are respectively positioned on opposite sides of the telecentric lens 50. The telecentric lens 50 receives the detection light emitted from the diffuser element 30 and guides the detection light onto the object under test 70 to form a uniform light spot. The detection light reflected or scattered by the object under test 70 returns to the telecentric lens 50 and is transmitted through the telecentric lens 50 to the image acquisition device. The telecentric lens 50 is, for example, an optical element with a preset transmittance-reflection ratio for the detection light, thus transmitting and reflecting part of the detection light. The image acquisition device 60 can be, for example, a CCD camera having a field of view 60 that at least partially covers the object under test 70 and the returned detection light. It should be noted that in different embodiments, the positions of the image acquisition device 60, the object under test 70, and the telecentric lens 50 can be changed. For example, at least two of the three can be arranged at a relative tilt angle. Or, the telecentric lens 50 and the image acquisition device 60 can be arranged on both sides of the object under test 70 respectively. In this case, after the detection light guided by the telecentric lens 50 is projected onto the object under test 70, at least part of the detection light can pass through the area around the object under test 70 or through the object under test 70 and be incident on the image acquisition device 60 on the other side of the object under test 70.
[0057] The above description is merely an embodiment of this utility model. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this utility model, but these improvements all fall within the protection scope of this utility model.
Claims
1. A light source, characterized by The light source comprises: a light emitting element for emitting detection light; a light guide element comprising a light guide portion having an input end and an output end, the input end being configured to couple the detection light into the light guide portion, the light guide portion being configured to conduct and homogenize the detection light, and the output end being configured to couple out the homogenized detection light; and a diffusion element disposed on an emission side of the light guide element and configured to diffuse the detection light emitted by the light guide element. The diffusion element is disposed on and in contact with an end surface of the output end of the light guide element.
2. The light source of claim 1, wherein The diffusion element covers the end surface of the output end of the light guide element.
3. The light source of claim 1, wherein 4. The light source according to claim 1, wherein: the light emitting element comprises one or more LED chips; or the light emitting element comprises at least two LED chips, the at least two LED chips emitting detection light having different peak wavelengths; or the light emitting element comprises a laser chip configured to emit excitation light and a wavelength conversion element configured to convert at least part of the excitation light into excitation light having a different wavelength range. The light guide portion comprises a light guide rod.
5. The light source of claim 1, wherein The light source further comprises a coupling element disposed between the light emitting element and the light guide element and configured to couple the detection light into the light guide element.
6. The light source of claim 1, wherein The coupling element comprises:
7. A light source as claimed in claim 6, characterized in that a collection lens configured to collect the detection light emitted by the light emitting element; and a converging lens configured to converge the detection light into converging light. The light source further comprises a telecentric lens disposed on an emission side of the diffusion element and configured to direct the detection light from the diffusion element to a measured object and to direct detection light returned via the measured object.
8. The light source of claim 1, wherein, The light source comprises any one of claims 1-8.
9. An illumination device, characterized by The illumination device comprises:
10. A detection system characterized by, a light source according to any one of claims 1-8; and a detection device configured to receive the detection light returned via the measured object and to obtain image information of the measured object based on the detection light. The detection device comprises: a light source according to any one of claims 1-8; and a detection device configured to receive the detection light returned via the measured object and to obtain image information of the measured object based on the detection light.