Light source device, lighting device and detection system

Abstract

The utility model discloses a light source device, a lighting device and a detection system, and belongs to the technical field of machine vision detection. The light source device is used for projecting illumination light towards a measured object, and comprises a light-emitting element used for emitting a first light beam; the light uniformizing element receives the first light beam and uniformizes the first light beam into a second light beam; and the light gathering element is used for gathering the second light beam at a preset light gathering point, and the light gathering point is located in front of the measured object. The light source device provided by the utility model can improve the size of the light spot projected on the measured object.

Description

Technical field

[0001] The utility model relates to the field of machine vision detection, in particular to a light source device, a lighting device and a detection system for machine vision detection. [Background Technology]

[0002] Machine vision inspection is widely used in the inspection of industrial products. By displaying the objects being inspected in images, it has the advantage of quickly and accurately inspecting the objects being inspected compared to previous 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 to be measured. The illumination light is reflected or scattered by the object to be measured and captured by the image detection device, displaying an image of the surface of the object to be measured, and then the object to be measured is detected based on the obtained image.

[0004] For objects of different sizes, there are different requirements for the size of the light spot projected onto the object. Generally speaking, the size of the light spot projected onto the object can be changed by adjusting the distance of the light source relative to the object. However, considering the volume of the detection system, this distance adjustment is generally limited. [Utility Model Content]

[0005] The purpose of the utility model is to provide a light source device, an illumination device and a detection system, which can increase the size of a light spot projected onto an object to be detected.

[0006] In a first aspect, the present invention provides a light source device for projecting illumination light toward an object to be measured, comprising:

[0007] a light-emitting element, configured to emit a first light beam;

[0008] a light homogenizing element, receiving the first light beam and homogenizing the first light beam into a second light beam; and

[0009] A focusing element is used to focus the second light beam on a preset focusing point, wherein the preset focusing point is located in front of the object to be measured.

[0010] In some possible implementations, the distance from the center point of the focusing element to the preset focusing point is smaller than the distance from the measured object to the preset focusing point.

[0011] In some possible implementations, the light homogenizing element includes:

[0012] A light homogenizing portion having a light incident surface and a light exiting surface, the light incident surface being used to receive the first light beam, the light homogenizing portion being used to homogenize the first light beam into the second light beam, and the light exiting surface being used to emit the second light beam, wherein the second light beam has a preset light spot on the light exiting surface.

[0013] In some possible implementations, an imaging element is further included, which is disposed between the preset focal point and the object to be measured, and is used to guide the second light beam to the object to be measured and image the preset light spot on the object to be measured.

[0014] In some possible implementations, the light homogenizing unit includes a light guide rod, which is configured to propagate the first light beam and internally reflect the first light beam multiple times in a traveling direction of the first light beam.

[0015] In some possible implementations, a coupling element is further included, configured to couple the first light beam to the light incident surface.

[0016] In some possible implementations, the coupling element includes:

[0017] a collecting lens, configured to collect the first light beam and reduce a divergence angle of the first light beam;

[0018] The converging lens receives the first light beam from the collecting lens and converges the first light beam.

[0019] In some possible implementations, the divergence angle of the first light beam collected by the collecting lens is not less than 120 degrees; and / or,

[0020] The converging angle of the first light beam after being converged by the converging lens is less than 50 degrees.

[0021] In some possible embodiments, the light-emitting element includes an LED chip; and / or, the light-emitting element includes a laser chip and a wavelength conversion element, wherein the laser chip is used to emit excitation light, and the wavelength conversion element receives the excitation light and converts at least part of the excitation light into an excited light having a wavelength range different from that of the excitation light.

[0022] In some possible implementations, there are at least two light-emitting elements, wherein the at least two light-emitting elements are used to emit the first light beams with different wavelengths.

[0023] In a second aspect, the present invention provides a lighting device comprising the light source device as described above.

[0024] In a third aspect, the present invention provides a detection system, comprising:

[0025] an illumination device for projecting illumination light onto the object to be measured, wherein the illumination device comprises the light source device as described above; and

[0026] The detection device receives illumination light from the object to be detected and obtains image information of the object to be detected based on the illumination light.

[0027] Beneficial effects of the utility model:

[0028] The light source device of the present invention focuses the homogenized second light beam to a preset focal point through a focusing element, and then the second light beam continues to travel as a divergent light beam, utilizing the expansion of the second light beam in space to increase the size of the light spot projected onto the object to be measured.

Brief Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. Among them:

[0030] Figure 1 This is a schematic diagram of a detection system according to an embodiment of the present application.

[0031] Description of reference numerals:

[0032] 10. Light source device; 20. Object to be measured; 30. Image acquisition device;

[0033] 101, light emitting element; 102, light homogenizing element; 103, light focusing element; 104, imaging element; 105, coupling element;

[0034] 1010, first light beam; 1011, second light beam;

[0035] 1020, light uniforming portion; 1021, light incident surface; 1022, light exit surface;

[0036] 3000, field of view. [Specific implementation method]

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] Figure 1An exemplary diagram of a detection system according to an embodiment of the present application is shown. The detection system according to an embodiment of the present application includes an illumination device and a detection device. The illumination device is used to project illumination light toward an object 20 to be detected. At least a portion of the illumination light is reflected or scattered after being incident on the surface of the object 20. The detection device is used to obtain the illumination light reflected or scattered by the object 20 to obtain image information of the object 20 for use in detecting the object 20.

[0039] The lighting device at least includes a light source device 10 and a carrier (not shown in the figure), the light source device 10 is used to generate illumination light for detecting the object 20 to be detected, and the carrier is used to carry the light source device 10, including but not limited to fixing, positioning, and adjusting the light source device 10. Figure 1 The light source device 10 according to the embodiment of the present application is described.

[0040] like Figure 1 As shown, the light source device 10 of an embodiment of the present application is used to project illumination light toward the object to be measured 20, and the light source device 10 includes a light-emitting element 101, a light-homogenizing element 102, and a light-converging element 103. The light-emitting element 101 is used to emit a first light beam 1010. The light-homogenizing element 102 is used to receive the first light beam 1010 and homogenize the first light beam 1010 into a second light beam 1011. The light-converging element 103 is used to converge the second light beam at a preset focal point, wherein the preset focal point is located in front of the object to be measured 20. The front in the application refers to a position forward in the direction of travel of the light beam, for example, the object to be measured 20 is located behind the preset focal point, that is, the direction in which the second light beam 1011 continues to travel after passing the preset focal point. It can be understood that the preset focal point is, for example, the focus of the light-converging element 103. The homogenized second light beam 1011 is converged to a preset focal point by the focusing element 103. After passing the preset focal point as a convergent beam, the second light beam 1011 continues to travel as a divergent beam. As the second light beam 1011 travels, the spot size of the second light beam 1011 gradually increases. Depending on the position of the object 20 to be measured and the preset focal point, the size of the spot of the second light beam 1011 projected onto the object 20 to be measured is different. For example, the closer the distance of the object 20 to be measured is to the preset focal point, the smaller the spot of the second light beam 1011 projected onto the object 20 to be measured, and vice versa. It should be noted that the distance of the object 20 to be measured relative to the preset focal point is the distance between the object 20 to be measured and the preset focal point along the travel path of the second light beam 1011.

[0041] In some embodiments of the present application, the distance from the center point of the focusing element 103 to the preset focusing point is shorter than the distance from the object under test 20 to the preset focusing point. Therefore, after the second light beam 1011 is focused by the focusing element 103, the light spot ultimately projected onto the object under test 20 is amplified, i.e., a larger light spot is projected onto the object under test 20. This helps expand the illuminated area of the object under test 20. More advantageously, the size of the light spot projected onto the object under test 20 can be adjusted within a limited volume.

[0042] The focusing element 103 can be selected as a focusing lens, which focuses the received second light beam 1011 to the preset focusing point; the focusing element 103 can also be selected as two or more cascaded lenses, which first collect the second light beam 1011 and then focus the collected second light beam 1011 to the preset focusing point.

[0043] The light-emitting element 101 is, for example, a point light source, i.e., the light emitted by the light-emitting element 101 can be equivalent to being emitted from a single point and gradually expanding as the light beam propagates. In one example, the first light beam 1010 emitted by the light-emitting element 101 has a divergence angle of not less than 120 degrees. The divergence angle of the first light beam 1010 emitted by the light-emitting element 101 is, for example, less than 180 degrees. In some examples, the divergence angle of the first light beam 1010 emitted by the light-emitting element 101 is, for example, less than 150 degrees.

[0044] In some embodiments of the present application, the light-emitting element 101 includes an LED chip. The light emitted by the LED chip has a Lambertian distribution, and thus the first light beam 1010 emitted by the LED chip has a predetermined divergence angle. The light-emitting element 101 may include at least two LED chips, and the light beams emitted by the at least two LED chips are mixed to form the first light beam 1010. The at least two LED chips may be arranged in an array or in another predetermined arrangement. The at least two LED chips may be configured to emit light beams of the same wavelength. Therefore, the combination of the at least two LED chips can increase the light intensity of the first light beam 1010, thereby increasing the brightness of the illumination light projected onto the object 20 under test. The at least two LED chips may also be configured to emit at least two different wavelengths. Based on the different material properties of the object 20 under test, illumination light of different wavelengths can produce different effects. For example, blue light has a short wavelength and weak penetration, making it more effective in detecting defects such as scratches. Infrared light has a long wavelength and strong penetration, and can be used to penetrate the surface of an object to detect materials beneath it. Therefore, when the at least two LED chips emit light beams of at least two different wavelengths, the ability to detect different material properties of the object 20 can be improved. In addition, in some examples, a drive control device can be provided to drive the at least two LED chips to partially or fully turn on or off the at least two LED chips.

[0045] In some embodiments of the present application, the light-emitting element 101 includes a laser chip and a wavelength conversion element (not shown). The laser chip is configured to emit excitation light, which is incident on the wavelength conversion element. The wavelength conversion element comprises a wavelength conversion material that converts at least a portion of the incident excitation light into converted light having a different wavelength range. For example, the laser chip emits blue excitation light, and the wavelength conversion element comprises a yellow fluorescent material. When the blue excitation light is incident on the yellow fluorescent material, the yellow fluorescent material converts at least a portion of the blue excitation light into converted light having a yellow wavelength range.

[0046] The light homogenizing element 102 includes a light homogenizing portion 1020, which is configured to be made of, for example, glass or resin material. The light homogenizing portion 1020 has a light incident surface 1021 and a light exit surface 1022. The first light beam 1010 from the light-emitting element 101 is coupled into the light homogenizing portion 1020 via the light incident surface 1021 and continues to propagate inside the light homogenizing portion 1020. While propagating the first light beam 1010, the light homogenizing portion 1020 homogenizes the first light beam 1010 to homogenize the first light beam 1010 into a second light beam 1011 with a uniform light distribution. The second light beam 1011 is emitted via the light exit surface 1022. The second light beam 1011 forms a preset light spot at the light-emitting surface 1022 of the light-evening portion 102, which has a shape matching that of the light-emitting surface 1022. The preset light spot has a uniform light distribution due to the homogenizing effect of the light-evening portion 102. Therefore, after the preset light spot is imaged onto the object to be measured 20 via the imaging element 104, it can evenly illuminate the object to be measured 20.

[0047] In some embodiments of the present application, the light homogenizer 1020 is configured as an elongated structure that propagates the first light beam 1010 along its length. During the propagation of the first light beam 1010, the light homogenizer 1020 utilizes its inner walls to internally reflect the first light beam 1010 multiple times, thereby changing the light distribution of the first light beam 1010 and homogenizing the first light beam 1010. In some examples, the light homogenizer 1020 is configured as a light guide rod. The light guide rod can be made of an optical medium such as glass or resin, which has a refractive index greater than that of air. During the propagation of the first light beam 1010 within the light guide rod, light incident on the light homogenizer 1020 at a large angle undergoes total internal reflection on the inner walls of the light guide rod, thereby homogenizing the first light beam 1010 through multiple total internal reflections. The light guide rod can be configured as a cylindrical structure, for example, with a circular or polygonal cross-sectional shape. The length of the light guide rod can be set to be no less than 10 mm to fully homogenize the first light beam 1010. Considering factors such as increased light loss, size, and cost due to excessive length of the light guide rod, the length of the light guide rod may be selected to be no more than 100 mm, or no more than 50 mm.

[0048] The side of the light guide rod is configured as a polished surface, obtained, for example, through a polishing process. If the side of the light guide rod has a certain degree of roughness, the interface between the light guide rod and the air will have many microstructures. These microstructures allow light rays with a radius greater than the critical angle for total internal reflection to pass through the microstructures and be transmitted from the side of the light guide rod. By polishing the side of the light guide rod, the smoothness of the side of the light guide rod is improved, the presence of microstructures is effectively reduced, and the utilization rate and uniformity of light are improved.

[0049] The light-entry surface of the light guide rod and / or the light-exiting surface of the light guide rod are also set as polished surfaces. When the light-entry surface of the light guide rod and / or the light-exiting surface of the light guide rod have a certain degree of roughness, the light-entry surface and / or the light-exiting surface have many microstructures. Since the light guide rod and air are optical media with different refractive indices, the presence of these microstructures will change the angular distribution of the first light beam 1010 incident on the interior of the light guide rod and / or the second light beam 1011 emitted through the light-exiting surface of the light guide rod, resulting in a decrease in the uniformity of the second light beam 1011 emitted through the light-exiting surface of the light guide rod. Therefore, by setting the light-entry surface and / or the light-exiting surface of the light guide rod as polished surfaces, the uniformity of the second light beam 1011 emitted through the light-exiting surface of the light guide rod can be improved.

[0050] In some embodiments of the present application, the light source device further includes an imaging element 104, which is disposed between the preset focal point and the object to be measured 20, and is configured to guide the second light beam 1011 onto the object to be measured 20, and image the preset light spot onto the object to be measured 20. The imaging element 104 can be configured to image the preset light spot onto the object to be measured 20 at a predetermined magnification. For example, the preset magnification can be set to one, that is, the preset light spot is imaged onto the object to be measured 20 at the same ratio. The preset magnification can also be greater than one or less than one, so that the light spot imaged onto the object to be measured 20 is enlarged or reduced relative to the light spot of the second light beam 1011 received by the imaging element 104. In some instances, the imaging element 104 is, for example, selected as an imaging lens, such as a telecentric lens.

[0051] In some embodiments of the present application, the imaging element 104 can change the traveling direction of the second light beam 1011 to Figure 1 For example, Figure 1 In the embodiment, the second light beam 1011 from the uniform light element 102 is focused by the focusing element 103 and then incident on the imaging element 104 in a horizontal direction. The imaging element 104 changes the direction of the second light beam 1011 so that it is incident downward on the object 20 to be measured below. This can make rational use of space and reduce the overall size. It should be noted that in different scenarios, the direction of the second light beam 1011 incident on the imaging element 104 and the direction of the second light beam 1011 after being guided by the imaging element 104 are not necessarily limited to Figure 1 The example given in .

[0052] According to the light source device 10 of an embodiment of the present application, the first light beam 1010 emitted by the light-emitting element 101 is homogenized by the light-homogenizing element 102 and outputs a uniform second light beam 1011 with a preset light spot. The second light beam 1011 is focused by the focusing element 103 and projected onto the object to be measured 20, thereby forming a uniform and enlarged light spot on the object to be measured 20.

[0053] In some embodiments of the present application, the light source device 10 further includes a coupling element 105 for coupling the first light beam 1010 into the light homogenizing element 102 to improve the utilization rate of the first light beam 1010 .

[0054] The coupling element 105 may include a collecting lens 1050 and a converging lens 1051, wherein the collecting lens 1050 and the converging lens 1051 are sequentially arranged on the optical path of the first light beam 1010. The collecting lens 1050 is used to collect the first light beam 1010 and reduce the divergence angle of the first light beam 1010, and the converging lens 1051 is used to receive the first light beam 1010 from the collecting lens 1050 and converge the first light beam 1010. The collecting lens 1050 can collect the first light beam 1010 emitted by the light-emitting element 101 as much as possible, and the converging lens 1051 can couple the collected first light beam 1010 to the light homogenizing element 102 as much as possible, thereby improving the utilization rate of the first light beam 1010, so that the illumination light ultimately projected onto the object under test 20 has a higher luminous flux, thereby improving the brightness of the illumination light.

[0055] Taking the light homogenizer 1020 having a light incident surface 1021 and a light exit surface 1022 as an example, the converging lens 1051 converges the first light beam 1010 onto the light incident surface of the light homogenizer 1020, thereby improving the coupling efficiency of the first light beam 1010. Specifically, the light incident surface of the light homogenizer 1020 can be set at or near the focus of the converging lens 1051. In an optional embodiment, after being converged by the converging lens 1050, the converging angle of the first light beam 1010 is no greater than 60 degrees, 50 degrees, or 40 degrees. For example, the converging angle of the first light beam 1010 can be selected to be 25 degrees, 30 degrees, or 35 degrees. Of course, the embodiments of the present application are not limited to this.

[0056] The light source device 10 of an embodiment of the present application is described in detail above. It can be understood that by efficiently collecting and coupling the first light beam 1010, homogenizing the first light beam 1010 to form a homogenized preset light spot, and amplifying the second light beam 1011 with the preset light spot, the light spot finally projected onto the object to be measured 20 has the advantages of being more uniform, brighter and having a larger light spot, which is conducive to improving the quality of obtaining image information of the object to be measured 20.

[0057] Continue to refer to Figure 1 , the embodiment of the present application also provides a lighting device, such as Figure 1 The lighting device is used to project illumination light onto the object to be measured 20. The illumination light illuminates the surface of the object to be measured 20 and is reflected or scattered from the surface of the object to be measured 20. By collecting the illumination light reflected or scattered by the surface of the object to be measured 20, image information of the object to be measured 20 is obtained, thereby realizing detection of the object to be measured 20.

[0058] In some embodiments, the lighting device includes the light source device 10 described above, which serves as the optical core of the lighting device, for example, and is configured to emit a second light beam 1011 having a preset light spot to form a uniform, bright, and large light spot on the object under test 20. It will be appreciated that the second light beam 1011 herein can serve as the illumination light for the lighting device. The lighting device also includes a carrier (not shown in the figure) that is used, for example, to secure, adjust, and support the light source device so that the light source device can be installed in a specific space and stably perform the function of projecting the second light beam 1011.

[0059] The embodiment of the present application also provides a detection system, which is used for machine vision detection, for example, to detect defects, labels, appearance, etc. of the object 20 to be detected. Figure 1 The detection device of the embodiment of the present application includes an illumination device and a detection device, wherein the illumination device includes the light source device 10 as described above, and the light source device 10 projects a second light beam 1011 onto the object to be measured 20 as illumination light, and realizes a uniform, bright, and large light spot on the object to be measured 20. The second light beam 1011 returning from the object to be measured 20 is collected by the detection device, thereby obtaining image information of the object to be measured 20 based on the second light beam 1011, and the image information includes, for example, defect information, label information, appearance information, etc. of the object to be measured 20. In the embodiment of the present application, because the light spot formed on the object to be measured 20 by the illumination light projected by the illumination device has good uniformity, brightness, and coverage, the image information of the object to be measured 20 that can be collected has better contrast, thereby improving detection accuracy and efficiency.

[0060] In some embodiments of the present application, the detection device includes an image acquisition device 30, and the image acquisition device 30 is used to collect the second light beam 1011 returned by the object to be detected 20. Figure 1As shown, in some examples, the image acquisition device 30 and the object under test 20 are respectively disposed on either side of the imaging element 104. The imaging element 104 receives the second light beam 1011 and directs the second light beam 1011 toward the object under test 20 on one side of the imaging element 104. The second light beam 1011, which is returned from the object under test 20, is then captured by the image acquisition device 30 through the imaging element 104. The imaging element 104 can, for example, be configured as an optical element having a predetermined transmission / reflection ratio for the second light beam 1011, thereby transmitting a portion of the second light beam 1011 and reflecting a portion of the second light beam 1011. The image acquisition device 30 can, for example, be configured as a CCD camera having a field of view 3000 that at least partially covers the object under test 20 and the returned second light beam 1011. It should be noted that, in different embodiments, the positions of the image acquisition device 30, the object to be measured 20 and the imaging element 104 can be changed. For example, at least two of the three can be arranged in a manner with a relative tilt angle. For another example, the imaging element 104 and the image acquisition device 30 can be arranged on both sides of the object to be measured 20, respectively. In this case, after the second light beam 1011 guided by the imaging element 104 is irradiated onto the object to be measured 20, at least part of the second light beam 1011 can be incident on the image acquisition device 30 on the other side of the object to be measured 20 from the surrounding of the object to be measured 20 or through the object to be measured 20.

[0061] The above is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements are all within the scope of protection of the present invention.

Claims

1. A light source device for projecting illumination light toward an object to be measured, characterized in that: include: a light-emitting element, configured to emit a first light beam; a light homogenizing element, receiving the first light beam and homogenizing the first light beam into a second light beam; as well as a focusing element, configured to focus the second light beam on a preset focusing point, wherein the preset focusing point is located in front of the object to be measured; The second light beam passes through the preset focal point as a converging light beam and then continues to travel as a diverging light beam. As the second light beam travels, the light spot of the second light beam gradually increases.

2. The light source device according to claim 1, wherein The distance from the center point of the focusing element to the preset focusing point is smaller than the distance from the measured object to the preset focusing point.

3. The light source device according to claim 1, wherein The light homogenizing element includes: A light homogenizing portion having a light incident surface and a light exiting surface, the light incident surface being used to receive the first light beam, the light homogenizing portion being used to homogenize the first light beam into the second light beam, and the light exiting surface being used to emit the second light beam, wherein the second light beam has a preset light spot on the light exiting surface.

4. The light source device according to claim 3, wherein It also includes an imaging element, which is arranged between the preset focal point and the object to be measured and is used to guide the second light beam to the object to be measured and image the preset light spot on the object to be measured.

5. The light source device according to claim 3, wherein The light homogenizing unit includes a light guide rod, which is used to propagate the first light beam and internally reflect the first light beam multiple times in a traveling direction of the first light beam.

6. The light source device according to claim 3, wherein: It also includes a coupling element for coupling the first light beam to the light incident surface.

7. The light source device according to claim 6, wherein: The coupling element comprises: a collecting lens, configured to collect the first light beam and reduce a divergence angle of the first light beam; The converging lens receives the first light beam from the collecting lens and converges the first light beam.

8. The light source device according to claim 7, wherein: The divergence angle of the first light beam collected by the collecting lens is not less than 120 degrees; and / or, The converging angle of the first light beam after being converged by the converging lens is less than 50 degrees.

9. The light source device according to claim 1, wherein The light-emitting element includes an LED chip; and / or, the light-emitting element includes a laser chip and a wavelength conversion element, wherein the laser chip is used to emit excitation light, and the wavelength conversion element receives the excitation light and converts at least part of the excitation light into an excited light having a wavelength range different from that of the excitation light.

10. The light source device according to claim 1, wherein There are at least two light-emitting elements, wherein the at least two light-emitting elements are used to emit the first light beams with different wavelengths.

11. A lighting device, characterized in that: The light source device comprises the light source device according to any one of claims 1 to 10.

12. A detection system, characterized in that: include: An illumination device for projecting illumination light onto the object to be measured, wherein the illumination device comprises the light source device according to any one of claims 1 to 10; as well as The detection device receives illumination light from the object to be detected and obtains image information of the object to be detected based on the illumination light.

Images