An illumination device and an image acquisition system with adjustable illumination area

Abstract

The application provides a lighting device with adjustable lighting area, which can switch between two light spot shapes by moving a light diaphragm, adapt to different lighting requirements, be applicable to long-distance uniform lighting, increase the use of the lighting device, save space for on-site equipment, and improve the stability of lighting during light spot switching without light axis inclination and uneven light intensity distribution. Furthermore, the light diaphragm hole is rectangular, and the light exit hole is circular, which provides matched lighting for linear array cameras and area array cameras. Furthermore, an image acquisition system using the lighting device is provided to provide a solution for exerting the efficiency of the lighting device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of light spot shaping, in particular to the field of light spot shaping using diaphragms. BACKGROUND

[0002] In the field of defect high-precision measurement and detection in semiconductor pre-process, post-process or other industries, different forms of illumination are often required for different detection requirements of the measured objects and different specifications of cameras.

[0003] Patent CN 206539983 U proposes that both the plano-convex lens and the optical accessory can change the distance from the light source by moving the focusing barrel, and the light spot size and shape can be adjusted according to the shape of the illuminated object. When it is necessary to adjust the corresponding light spot shape according to different illuminated objects, the corresponding optical accessory is replaced. This technical solution changes the distance between the center of the variable focus lens and the light emitting object to change the light shape of the light beam output to meet different lighting needs, and occupies a considerable market share in the current industry application. However, this technical solution has a major defect: during the adjustment of the lens, the light axis is inclined and the illumination distribution is uneven due to assembly deviation or frequent movement, increasing the difficulty of image recognition and judgment in defect detection.

[0004] Patent CN 114839785 A proposes that by changing a plurality of thin cylinders, i.e. changing the shape of the diaphragm aperture, the light spot shaping is realized. When adjusting the light spot shape, the patent sets multiple cylinders, and the measurement value of the optical power measurement assembly is fed back to the machine to adjust the position of the cylinder, and this process is repeated and iterated until the target light spot is adjusted. This technical solution also has a major defect: although the shape of the light output can be arbitrarily changed, the process is relatively cumbersome, and the number and size of the cylinders determine that the patent is limited in application to the illumination area, and is not suitable for long-distance uniform illumination.

[0005] There are also some existing technical solutions that change the light spot shape by replacing the diaphragm, and the disadvantage is that it is more troublesome to disassemble and install when replacing, and it must be stopped for replacement, affecting production efficiency.

[0006] In summary, in the current defect detection technology field, although the demand for light spot shaping has always been strong, the technical solutions so far have major defects and cannot achieve good results. SUMMARY

[0007] The present application aims to provide a lighting device with adjustable lighting area, which can switch between two light spot shapes by moving a diaphragm, adapt to different lighting needs, and be applicable to long-distance uniform lighting, increase the use of the lighting device, and save space for on-site equipment. In addition, for the method of changing the focal length of a variable focus lens, there is no problem of optical axis tilt and uneven illumination distribution because the lens is not moved, which improves the stability of the lighting during light spot switching.

[0008] In a first aspect, the present application provides a lighting device with adjustable lighting area, which comprises:

[0009] a housing 1, a light source assembly 2, and a diaphragm 3.

[0010] The housing 1 is the shell of the device.

[0011] The light source assembly 2 is installed at one end of the housing 1 and is used to emit a lighting beam with a desired divergence angle.

[0012] The diaphragm 3 is located in front of the light source assembly 2. The diaphragm 3 has a diaphragm hole.

[0013] The other end of the housing 1 has an exit hole 4. The shape of the exit hole 4 is different from that of the diaphragm hole. The exit hole 4 is larger than the diaphragm hole.

[0014] The diaphragm 3 can move between the light source assembly 2 and the exit hole 4,

[0015] When the diaphragm 3 is at point M, part of the lighting beam cannot pass through the diaphragm hole, but all of the lighting beam can pass through the exit hole 4 after passing through the diaphragm hole. The light spot shape output by the lighting beam is the same as the shape of the diaphragm hole.

[0016] When the diaphragm 3 is at point N, part of the lighting beam can pass through the exit hole 4 after passing through the diaphragm hole. The light spot shape output by the lighting beam is the same as the shape of the exit hole 4.

[0017] In some embodiments, the present application provides a lighting device with adjustable lighting area, which comprises:

[0018] The diaphragm hole is rectangular, and the exit hole 4 is circular.

[0019] The distance from the light source assembly 2 to the exit hole 4 is L. The diameter of the exit hole 4 is D. The diameter of the circumscribed circle of the diaphragm hole is 2R. The distance between N and M is l. Then 2R<D<0.66*L and l<2.83*(D-2R).

[0020] In some embodiments, the present application provides a lighting device with adjustable lighting area, comprising:

[0021] The inner wall of the shell 1 is coated with a reflective coating.

[0022] In some embodiments, the present application provides a lighting device with adjustable lighting area, further comprising:

[0023] A lead screw 5 is mounted on the shell 1 for driving the diaphragm 3 to move between the light source assembly 2 and the light exit hole 4.

[0024] In some embodiments, the present application provides a lighting device with adjustable lighting area, further comprising:

[0025] A light homogenizing member 6 is mounted in front of the diaphragm 3 for homogenizing the lighting beam when output.

[0026] In the second aspect, the present application provides an image acquisition system using the lighting device 7 as described in the first aspect, further comprising:

[0027] A camera 8 and a stage 9.

[0028] The camera 8 is located on one side of the stage 9 and aims at the surface of the object under test on the stage 9 from a high position.

[0029] The lighting device 7 is located on the other side of the stage 9 and is at an angle or directly above the stage 9, and aims at the surface of the object under test on the stage 9 from a high position.

[0030] The lighting beam emitted by the lighting device 7 is reflected by the surface of the object under test on the stage 9 and projects an image onto the camera 8 on the side.

[0031] In the third aspect, the present application provides an image acquisition system using the lighting device 7 as described in the first aspect, further comprising:

[0032] A camera 8, a stage 9 and a beam splitter 10.

[0033] The camera 8 is located above the stage 9 and aims at the surface of the object under test.

[0034] The beam splitter 10 is located between the camera 8 and the surface of the object under test.

[0035] The lighting device 7 is located on the side of the stage 9 and at the same height as the beam splitter 10.

[0036] The lighting beam emitted by the lighting device 7 enters the beam splitter 10 from a horizontal direction, is reflected by the beam splitter 10 and then illuminates the surface of the object under test in a vertical direction, and the image is projected onto the camera 8 in a vertical direction through the half mirror after being reflected by the surface of the object under test.

[0037] The beneficial effects of the present application are:

[0038] 1) By moving only one light barrier 3, the switching of two spot shapes is cleverly achieved, adapting to different lighting needs.

[0039] 2) It can be applied to long-distance uniform illumination, such as achieving good lighting effect when the working distance is 1000mm.

[0040] 3) It increases the use of the lighting device 7, and saves space for on-site equipment.

[0041] 4) For the current application of changing the focal length of the variable focus lens, there is no problem of optical axis tilt and uneven illumination because it does not involve the movement of the lens, which improves the stability of the lighting during the spot switching process.

[0042] 5) The convenience of the spot switching method lays the foundation for the automation of the spot switching of the lighting device 7.

[0043] 6) The light homogenizing member 6 is added in front of the light barrier 3, which improves the uniformity of the illumination beam.

[0044] 7) The image acquisition system using the lighting device 7 is proposed, which provides a solution to the performance of the lighting device 7. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. However, those skilled in the art should understand that the drawings described below are only some examples of the present application, and do not limit its scope.

[0046] Figure 1a And Figure 1b is a structural schematic diagram of a specific embodiment of a lighting device with adjustable lighting area of the present application. Among them, Figure 1a is an assembly drawing, Figure 1b is an exploded view.

[0047] Figure 2 is a principle schematic diagram of a specific embodiment of a lighting device with adjustable lighting area of the present application.

[0048] Figure 3 is an effect schematic diagram of a specific embodiment of a lighting device with adjustable lighting area of the present application.

[0049] Figure 4A structure diagram of a specific embodiment of an image acquisition system applying the lighting device according to the first aspect.

[0050] Figure 5 A structure diagram of a specific embodiment of an image acquisition system applying the lighting device according to the first aspect. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be understood by those skilled in the art that the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, those skilled in the art can make any appropriate modifications or variations to obtain all other embodiments.

[0052] In a first aspect, the embodiments of the present application provide a lighting device with adjustable lighting area, which comprises:

[0053] A housing 1, a light source assembly 2 and a diaphragm 3.

[0054] The housing 1 is the shell of the device.

[0055] The light source assembly 2 is installed at one end of the housing 1, and is used to emit a lighting beam with a desired divergence angle.

[0056] The diaphragm 3 is located in front of the light source assembly 2. The diaphragm 3 has a diaphragm hole.

[0057] The other end of the housing 1 has a light exit hole 4. The shape of the light exit hole 4 is different from the shape of the diaphragm hole. The light exit hole 4 is larger than the diaphragm hole.

[0058] The diaphragm 3 can move between the light source assembly 2 and the light exit hole 4,

[0059] When the diaphragm 3 is located at point M, part of the lighting beam cannot pass through the diaphragm hole, but all the lighting beam can pass through the light exit hole 4 after passing through the diaphragm hole. The spot shape output by the lighting beam is the same as the shape of the diaphragm hole.

[0060] When the diaphragm 3 is located at point N, part of the lighting beam can pass through the light exit hole 4 after passing through the diaphragm hole. The spot shape output by the lighting beam is the same as the shape of the light exit hole 4.

[0061] In the present embodiment, as shown in Figure 1a and Figure 1b The lighting device comprises the housing 1, the light source assembly 2 and the diaphragm 3. Figure 1a An assembly drawing, Figure 1bThe shell 1, shape and no special requirements, round, square, multi-edge, etc., are possible. The light source assembly 2, can emit the expected divergence angle of the light beam. The light source assembly 2, light source can use LED or point light fiber bundle. In front of the light source set light optical components, can be a certain degree of convergence of the light source emitted divergent light rays, convergence shaping, so that it meets the requirements of the expected divergence angle. The light optical components, in most cases can use aspheric lens. Of course, not all aspheric lens has light collection function, need to select the appropriate surface according to the prior art parameters. Choose other ways to collect light, such as setting a reflector behind the light source, or set a circle of mirrors, can achieve the same effect, need to be designed according to the use requirements, in order to meet the requirements of the expected divergence angle in this embodiment. The expected divergence angle, according to the on-site use requirements of the lighting device 7: can not be too small, otherwise the spot area is too small, can not cover the surface of the measured object needs to be detected, will lead to incomplete detection; also can not be too large, otherwise the spot area is too large, may lead to light intensity is not enough, thus affecting the detection effect. The specific value, because of many influencing factors, it is difficult to give a unified standard, but can be obtained by calculation, simulation, or a limited number of field tests. The light source assembly 2 close to the shell 1, one end of the installation, convenient for external power supply. The front of the light source assembly 2, is the diaphragm 3. The diaphragm 3 on the opening of the diaphragm hole, the shape of the diaphragm hole and no special requirements, depending on the shape of the spot required by the scene. The other end of the shell 1 of the light hole 4, itself on the shape is not required, mainly depending on the shape of the spot required by the scene. Only, because the technical effect of the lighting device is adjustable illumination area, that is, the shape of the spot is variable, so, if the shape of the light hole 4 and the shape of the diaphragm hole is consistent, then the adjustable illumination area function is partially lost significance, only for the same shape of the spot adjustment area size. The effect of adjustable illumination area, from the diaphragm 3 can move between the light source assembly 2 and the light hole 4. This is an important innovation of the present application.The existing spot light adjustment mainly has the following ways: 1) through changing the distance between the variable focus lens center and the light emitting object, but the disadvantage is that in the process of adjusting the lens, the light axis is inclined and the light intensity distribution is uneven due to assembly deviation or frequent movement, which increases the difficulty of image recognition and judgment in defect detection; 2) some patents set multiple cylinders, and the position of the cylinder is adjusted by the feedback of the measurement value of the optical power measurement component, and this process is repeated until the target spot is adjusted, and this technical solution also has its major defects, although it can change the shape of the light output arbitrarily, but the process is relatively complicated, and the number and size of the cylinders determine that the technical solution is limited to the illumination area, and is not suitable for long distance uniform illumination; 3) through replacing the diaphragm to realize the switching of the spot shape, the disadvantage is that it is more troublesome to disassemble and install when replacing, and it must be stopped for replacement, which affects the production efficiency. The present application, by moving one of the diaphragms 3, cleverly realizes the switching of two spot shapes, adapts to different lighting needs, and can be applied to long distance uniform illumination, increases the use of the lighting device, and saves space for on-site equipment; In addition, for the way of changing the focal length of the variable focus lens which is more commonly used at present, there is no problem of light axis inclination and uneven light intensity distribution because it does not involve the movement of the lens, which improves the stability of the lighting in the spot switching.

[0062] Specifically, the principle of switching the spot shape by moving one of the diaphragms 3 is as follows: Figure 2As shown. The illumination beam emitted by the light source assembly 2, conforming to the expected divergence angle, shines forward along a straight line, and the outermost rays of the illumination beam all conform to the expected divergence angle. Taking the luminous edge point O′ on one side of the light source assembly 2 as an example. When the aperture 3 is located at point M, the light propagating along the straight line O′A is blocked by the light shield of the aperture 3 and cannot continue to propagate. The angle of the light emitted from point O′ gradually decreases. When the divergence angle decreases to the point where it is emitted forward along the straight line O′B, because point B is exactly located at the intersection of the light shield of the aperture 3 and the aperture aperture, the light passes directly through the aperture aperture and forms the light spot on the surface of the object under test. At this time, whether the illumination beam can illuminate the surface of the object under test is limited by the aperture aperture. Therefore, the shape of the light spot projected onto the surface of the object under test is the same as the shape of the aperture aperture. When the aperture 3 is located at point N, the light rays propagating along the straight line O′C are not restricted by the aperture 3 and pass directly through the aperture, but ultimately project onto the outer casing without passing through the light exit hole 4. When the divergence angle is slightly smaller, the light rays propagating along the straight line O′A, as they propagate forward, pass directly through the light exit hole 4 because point A is located at the edge of the light exit hole 4, forming a light spot on the surface of the object under test. At this time, whether the illumination beam can illuminate the surface of the object under test is limited by the light exit hole 4; therefore, the shape of the light spot projected onto the surface of the object under test is the same as the shape of the light exit hole 4. In short, when the aperture 3 is located at point M, a portion of the illumination beam cannot pass through the aperture, but the portion of the illumination beam that passes through the aperture can pass through the light outlet 4. That is, whether the illumination beam can illuminate the surface of the object under test is limited by the aperture 3. Therefore, the shape of the light spot output by the illumination beam is the same as the shape of the aperture. When the aperture 3 is located at point N, all of the illumination beam may pass through the aperture, or only a portion of the illumination beam may pass through the aperture. However, ultimately, after passing through the aperture, a portion of the illumination beam is still blocked by the housing 1, and only a portion can pass through the light outlet 4. That is, whether the illumination beam can illuminate the surface of the object under test is ultimately limited by the housing 1. Therefore, the shape of the light spot output by the illumination beam is the same as the shape of the light outlet 4.

[0063] The movement of the aperture 3 can be achieved in various ways. For example, a lead screw 5, a built-in slide rail, a telescopic sleeve, or other methods capable of linear motion can all be applied to this embodiment after simple design.

[0064] The following points need further explanation: 1) Although Figure 1a and Figure 1b The shape of the light-emitting hole 4 is the same as the cross-sectional dimension of the housing 1, but the light-emitting hole 4 can be smaller than the cross-sectional dimension, simply by adding a baffle to the end face. 2) As Figure 2The light-emitting hole 4 is larger than the diaphragm hole, and the degree of the light-emitting hole 4 being larger than the diaphragm hole needs to be determined according to specific needs on the spot, mainly needs to meet the switching condition of the shape of the light spot, that is, under a certain divergence angle, meets the requirement that the illumination beam is limited by the diaphragm 3 at the M point and is ultimately limited by the light-emitting hole 4 at the N point, and also meets the requirements of the size and intensity of the light spot on the spot, which needs to be considered comprehensively. Figure 3 As shown in FIG. 8, it is the illumination effect when the working distance (the distance from the edge of the light-emitting hole 4 to the surface of the object to be measured) is 1000 mm.

[0065] In some embodiments, the present application provides an illumination device with adjustable illumination area:

[0066] The diaphragm hole is rectangular, and the light-emitting hole 4 is circular.

[0067] The distance from the light source assembly 2 to the light-emitting hole 4 is L. The diameter of the light-emitting hole 4 is D. The diameter of the circumscribed circle of the diaphragm hole is 2R. The distance between the N and M is l. Then 2R < D < 0.66 * L and l < 2.83 * (D-2R).

[0068] In this embodiment, it is recommended to use a rectangular diaphragm hole and a circular light-emitting hole 4. This is because: 1) the rectangular light spot is suitable for a linear array camera 8, and the circular light spot is suitable for a planar array camera 8, so these two shapes of light spots are most commonly used in defect detection. 2) As mentioned earlier, when the shape of the light spot and the shape of the diaphragm hole are the same, more illumination beams are lost, and when the shape of the light spot and the shape of the light-emitting hole 4 are the same, fewer illumination beams are lost. The light-emitting hole 4 should be larger than the diaphragm hole. Accordingly, a rectangle is always a little smaller relative to its circumscribed circle; therefore, using a circular light-emitting hole 4 and then shrinking it to a rectangular diaphragm hole required by the diaphragm 3 has a higher utilization rate of the illumination beam. Conversely, a rectangle itself needs to lose more illumination beams to obtain, and the loss of illumination beams to obtain a smaller circle than a rectangle is more. In summary, the setting of the rectangular diaphragm hole and the circular light-emitting hole 4 can not only meet the conventional requirements of defect detection for the shape of the light spot, but also more effectively utilize the illumination beam provided by the light source assembly 2. When the size of the diaphragm hole and the light-emitting hole 4 meets the formula given, the embodiment can be realized, and the effect is as shown in FIG. 8. Figure 3 As shown in FIG. 8, a is the light spot of a rectangle consistent with the shape of the diaphragm hole, and b is the light spot of a circle consistent with the shape of the light-emitting hole 4.

[0069] In some embodiments, the present application provides an illumination device with adjustable illumination area:

[0070] The inner wall of the shell 1 is coated with a reflective coating.

[0071] In the embodiment, in order to make more effective use of the illumination beam, the inner wall of the shell 1 is coated with the reflective coating. As mentioned above, in the illumination beam emitted by the light source assembly 2, a considerable part is blocked by the diaphragm 3 or the shell 1 and then reflected again in the shell 1. After being coated with the reflective coating, the reflective efficiency is improved, so that the blocked light rays can reach the surface of the object to be detected after multiple reflections to the greatest extent, the intensity of the light spot is enhanced, and the utilization rate of the illumination beam is improved.

[0072] In some embodiments, the application provides an illumination device with adjustable illumination area, which further comprises:

[0073] A lead screw 5 is installed on the shell 1 and used to drive the diaphragm 3 to move between the light source assembly 2 and the light exit hole 4.

[0074] In the embodiment, as shown in Figure 1a and Figure 1b , the diaphragm 3 is driven to move linearly back and forth by the rotation of the lead screw 5 between the M point and the N point, so as to realize the shape switching of the light spot and adjust the illumination area. The use of the lead screw 5 also lays a foundation for further improving the automation degree of the illumination device 7.

[0075] In some embodiments, the application provides an illumination device with adjustable illumination area, which further comprises:

[0076] A light homogenizing member 6 is installed in front of the diaphragm 3 and used for homogenization processing of the illumination beam when it is output.

[0077] In the embodiment, as shown in Figure 1b , the illumination beam is homogenized by the light homogenizing member 6. The light homogenizing member 6 can use microlens array (MLA), diffuser and other elements that have existed in the optical system or will appear in the future to play the role of light homogenization. The role of the light homogenizing member 6 is the expected light homogenization of the light homogenizing member 6 itself. The better the light homogenization effect of the light homogenizing member 6, the more difficult the processing is, and a balance between the on-site demand and the cost should be made when selecting. If the position of the light homogenizing member 6 is between the light source assembly 2 and the diaphragm hole, the edge light of the illumination beam will increase, which reduces the utilization rate of the illumination beam. After the illumination beam passes through the diaphragm hole, the homogenization processing is performed, which can avoid the reduction of the utilization rate of the illumination beam while improving the uniformity of the light spot to obtain a better quality image for image recognition processing.

[0078] In the second aspect, the embodiment of the application provides an image acquisition system applying the illumination device 7 as described in the first aspect, which further comprises:

[0079] Camera 8 and carrier 9.

[0080] The camera 8 is on one side of the carrier 9, and is directed from above to the surface of the object under test on the carrier 9.

[0081] The lighting device 7 is on the other side of the carrier 9, and is directed from above to the surface of the object under test on the carrier 9.

[0082] The lighting beam emitted by the lighting device 7 is reflected by the surface of the object under test on the carrier 9, and projects an image onto the camera 8 on the side.

[0083] In the embodiment, as shown in Figure 4 the lighting device 7 is used to form the image acquisition system. The system also includes the camera 8 and the carrier 9. The camera 8 should be able to work in coordination with the shape of the light spot of the lighting device 7. The camera 8 is directed from the side to the surface of the object under test, and obtains the image projected by the reflection of the surface of the object under test. The lighting device 7 is installed in a position directly above the surface of the object under test, or is tilted in a direction different from the position of the camera 8, and is directed from the side to the surface of the object under test. The specific installation position should be adjusted in coordination with the camera 8, and should ensure that the lighting beam emitted by the lighting device 7 can be received by the camera 8. The propagation path of the lighting beam is: from the lighting device 7 to the surface of the object under test, and after reflection, the image is projected to the camera 8. Figure 4 The dotted line part in the figure indicates the position of the light spot on the surface of the object under test.

[0084] In a third aspect, an embodiment of the present application provides an image acquisition system using the lighting device 7 as described in the first aspect. The system also includes:

[0085] Camera 8, carrier 9 and beam splitter 10.

[0086] The camera 8 is above the carrier 9, and is directed to the surface of the object under test.

[0087] The beam splitter 10 is between the camera 8 and the surface of the object under test.

[0088] The lighting device 7 is on the side of the carrier 9, and is at the same height as the beam splitter 10.

[0089] The lighting beam emitted by the lighting device 7 enters the beam splitter 10 from the horizontal direction, is reflected by the beam splitter 10, and is directed to the surface of the object under test in the vertical direction, and then the image is projected to the camera 8 in the vertical direction through the half mirror.

[0090] In the embodiment, the image acquisition system is constructed by using the illumination device 7 as shown in the figure. The system further comprises the camera 8, the carrier 9 and the beam splitter 10. As mentioned above, the camera 8 should be able to work in coordination with the shape of the light spot of the illumination device 7. In the image acquisition system, the illumination device 7 becomes a coaxial light source of the camera 8. Specifically, the camera 8 is vertically opposite to the surface of the object to be measured. The beam splitter 10 is between the camera 8 and the surface of the object to be measured and is opposite to the camera 8 and the surface of the object to be measured in the vertical direction. The illumination device 7 is beside the carrier 9 and is at the same height as the beam splitter 10, i.e. at the same horizontal plane. The working principle of the image acquisition system is that the illumination light beam emitted by the illumination device 7 enters the beam splitter 10 from the horizontal direction, changes direction after being reflected by the beam splitter 10, and is illuminated to the surface of the object to be measured along the vertical direction, and then the image is projected to the camera 8 along the vertical direction through the half mirror after being reflected by the surface of the object to be measured.

[0091] The preferred embodiments of the present application are described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations without creative labor based on the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the concept of the present application and the prior art should be within the protection scope defined by the claims.

Claims

1. A lighting device with adjustable lighting area, characterized in that, The lighting device includes: a housing (1), a light source assembly (2), and an aperture diaphragm (3); The housing (1) is the outer shell of the device; The light source assembly (2) is installed at one end of the housing (1) and is used to emit a lighting beam with an expected divergence angle; The aperture diaphragm (3) is located in front of the light source assembly (2); an aperture hole is provided on the aperture diaphragm (3); Another end of the housing (1) is provided with a light output hole (4); the shape of the light output hole (4) is different from that of the aperture hole; the light output hole (4) is larger than the aperture hole; The aperture diaphragm (3) can move between the light source assembly (2) and the light output hole (4), When the aperture diaphragm (3) is at point M, part of the lighting beam cannot pass through the aperture hole, but all the lighting beams can pass through the light output hole (4) after passing through the aperture hole, and the shape of the light spot output by the lighting beam is the same as that of the aperture hole; When the aperture diaphragm (3) is at point N, part of the lighting beam can pass through the light output hole (4) after passing through the aperture hole, and the shape of the light spot output by the lighting beam is the same as that of the light output hole (4).

2. The lighting device according to claim 1, wherein: The aperture hole is rectangular, and the light output hole (4) is circular; Taking the distance from the light source assembly (2) to the light output hole (4) as L; taking the diameter of the light output hole (4) as D; taking the diameter of the circumscribed circle of the aperture hole as 2R; taking the distance between N and M as l; then: 2R < D < 0.66 * L and l < 2.83 * (D - 2R).

3. The lighting device according to claim 1, wherein: The inner wall of the housing (1) is coated with a reflective coating.

4. The lighting device according to any one of claims 1-3, characterized in that, The lighting device further includes: a lead screw (5) installed on the housing (1) and used to drive the aperture diaphragm (3) to move between the light source assembly (2) and the light output hole (4).

5. The lighting device according to claim 4, characterized in that, The lighting device further includes: a light homogenizing member (6) installed in front of the aperture diaphragm (3) and used for homogenizing the lighting beam during output.

6. An image acquisition system employing the lighting device (7) as described in claim 1, characterized in that, The system further includes: a camera (8) and a stage (9); The camera (8) is on one side of the stage (9) and is aligned from above with the surface of the object to be measured on the stage (9); The lighting device (7) is on the other side and at a certain angle or directly above the stage (9) and shines from above onto the surface of the object to be measured on the stage (9); The lighting beam emitted by the lighting device (7) is reflected by the surface of the object to be measured on the stage (9) and projects an image onto the camera (8) on the side.

7. An image acquisition system employing the lighting device (7) as described in claim 1, characterized in that, The system further includes: a camera (8), a stage (9), and a beam splitter (10); The camera (8) is above the stage (9) and is directly facing the surface of the object to be measured; The beam splitter (10) is between the camera (8) and the surface of the object to be measured; The lighting device (7) is on the side of the stage (9) and is at the same height as the beam splitter (10); The illumination beam emitted by the illumination device (7) enters the beam splitter (10) from the horizontal direction, and after being reflected by the beam splitter (10), it shines on the surface of the object to be measured in the vertical direction. After being reflected by the surface of the object to be measured, the image is projected onto the camera (8) in the vertical direction through the beam splitter.

Images