CN218298724U - Multiple illumination optical system applied to appearance detection - Google Patents

Abstract

The application provides a plurality of illumination optical systems applied to appearance detection, which comprise an imaging module, a lens module and an integrated coaxial light source module; the imaging module, the lens module and the integrated coaxial light source module are sequentially arranged, the imaging module and the lens module are coaxial, and a first central axis of the integrated coaxial light source module is vertical to a central axis of the lens module; the integrated coaxial light source module comprises a first light source, a first lens, a second lens and a third lens which are sequentially arranged in the first axial direction; the integrated coaxial light source module further comprises a second light source and a fourth lens which are sequentially arranged in the second axial direction, the fourth lens is positioned on one side, close to the plane of the third lens, of the second lens, and the second lens is also positioned in the second axial direction; multiple illumination modes are applied to the same optical system through the integrated design of the optical system, and the function of detecting multiple appearance defects at high speed by using a single imaging system is realized.

Description

Multiple illumination optical system applied to appearance detection

Technical Field

The embodiment of the utility model provides a relate to the lighting technology field, especially relate to a be applied to multiple illumination optical system that outward appearance detected.

Background

The electronic product shell can generate some bad appearances in the production process, such as defects of collision, scratch, pressure injury, dirt, broken filaments, watermarks, gaps, sand lines, demoulding, wrinkles, unevenness and the like.

Since the appearance defects are small and the variety is large, most of the appearance defects are detected by human eyes at present, and the detection efficiency is low. In the conventional automatic detection equipment, in the face of complicated appearance defects, because the limitation of application scenes can only use different optical systems to image part of defects, the automatic detection equipment is provided with a plurality of different optical systems. Therefore, the cost, the occupied area and the detection time of the equipment are improved.

SUMMERY OF THE UTILITY MODEL

In view of this, the embodiment of the utility model provides a be applied to multiple illumination optical system that outward appearance detected, through optical system's integrated design with multiple illumination mode be applied to in the same set of optical system to use high-speed camera to shoot, realized the function that single imaging system detected multiple appearance defect at a high speed.

In a first aspect, an embodiment of the present invention provides a multiple illumination optical system applied to appearance detection, including an imaging module, a lens module, and an integrated coaxial light source module;

the imaging module, the lens module and the integrated coaxial light source module are sequentially arranged, the imaging module is coaxial with the lens module, and a first central axis of the integrated coaxial light source module is vertical to a central axis of the lens module;

the integrated coaxial light source module comprises a first light source, a first lens, a second lens and a third lens which are sequentially arranged in a first axial direction, wherein the first lens, the second lens and the third lens are planar lenses; the integrated coaxial light source module further comprises a second light source and a fourth lens which are sequentially arranged in the direction of a second axis, and the second lens is also arranged in the direction of the second axis; the fourth lens is positioned on one side of the second lens close to the third lens, and the second light source is positioned on one side of the fourth lens away from the second lens; illuminating light emitted by the first light source sequentially penetrates through the first lens and the second lens and then is reflected by the third lens to irradiate the surface of an object to be measured to form a first path of illuminating light; the illumination light emitted by the second light source penetrates through the fourth lens, is reflected by the second lens and then is reflected by the third lens to irradiate the surface of the object to be measured, so that a second path of illumination light is formed; and the illumination light reaching the surface of the object to be measured is reflected by the object to be measured and then sequentially penetrates through the third lens and the lens module to enter the imaging module.

Optionally, the first light source includes a plurality of light sources, and the second light source includes a light source; the light source comprises a light emitting diode, and the size of the light emitting diode is C, wherein C is more than 0 and less than or equal to 3mm multiplied by 3mm.

Optionally, the refractive index of the first lens is n1, and the abbe number of the first lens is V1; the refractive index of the second lens is n1, and the Abbe number of the second lens is V1; the refractive index of the third lens is n3, and the Abbe number of the third lens is V3; the refractive index of the fourth lens is n4, and the Abbe number of the fourth lens is V4;

wherein n1 is more than 1.461 and less than 1.650, and V1 is more than 40 and less than 70; n2 is more than 1.461 and less than 1.650, V2 is more than 40 and less than 70; n3 is more than 1.461 and less than 1.650, and V3 is more than 40 and less than 70; n4 is more than 1.461 and less than 1.650, and V4 is more than 40 and less than 70.

Optionally, the first lens includes a diffusion plate, and the transmittance of the diffusion plate is T, where T is greater than or equal to 70%.

Optionally, the surface of the second lens is plated with a first light splitting film, and the light splitting wavelength of the first light splitting film is 400nm to 700nm; the surface of the third lens is plated with a second light splitting film, and the light splitting wavelength of the second light splitting film is 400-700 nm;

the ratio of the transmittance to the reflectivity of the first light splitting film and the ratio of the transmittance to the reflectivity of the second light splitting film are adjustable.

Optionally, the ratio of the transmittance to the reflectance of the first light splitting film is 7; the transmittance and reflectance ratio of the second dichroic film is 5.

Optionally, the fourth lens includes a fresnel lens, and a distance between the fresnel lens and the fourth lens is adjustable.

Optionally, a distance between the end surface of the third lens close to the object to be measured and the surface of the object to be measured is 55 ± 2mm.

Optionally, the lens module includes a 0.3-time telecentric lens, and a distance between the end face of the 0.3-time telecentric lens close to the object to be measured and the surface of the object to be measured is 100 ± 2mm.

Optionally, the multiple illumination optical systems further include a light control module, where the light control module is electrically connected to the first light source and the second light source, respectively, and controls the first light source and the second light source to alternately emit light.

The embodiment of the utility model provides a be applied to multiple illumination optical system that outward appearance detected through illuminating source's among the rational design optical system structure and position, is applied to same set of optical system with multiple lighting methods to use high-speed camera to shoot, realized single imaging system high-speed multiple appearance defect's of detection function, reduced check out test set's cost, area, improved detection efficiency.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

fig. 1 is a schematic diagram of various illumination optical systems applied to appearance inspection according to the present application;

FIG. 2 is a schematic diagram of an application of the optical system provided in FIG. 1;

fig. 3 is a schematic structural diagram of an integrated coaxial light source module provided in the present application;

FIG. 4 is a graph of the light illumination energy distribution of the integrated coaxial light source module provided in FIG. 3;

FIG. 5 is an actual view of a metameric defect obtained using various illumination optical systems provided herein;

FIG. 6 is a schematic diagram illustrating image stitching effects after the first path of illumination light is used for illuminating and image taking in FIG. 3;

fig. 7 is a schematic diagram of image stitching effect after the second path of illumination light is used for illuminating and image taking in fig. 3.

Detailed Description

To make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described completely through the detailed description with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work based on the embodiments of the present invention all fall into the protection scope of the present invention.

Examples

Fig. 1 is a schematic diagram of various illumination optical systems applied to appearance inspection according to the present application; FIG. 2 is a schematic diagram of an application of the optical system provided in FIG. 1; fig. 3 is a schematic structural diagram of an integrated coaxial light source module provided in the present application; FIG. 4 is a light illumination energy distribution diagram of the integrated coaxial light source module provided in FIG. 3; fig. 5 is an actual view of a metameric defect obtained using various illumination optical systems provided herein. As shown in fig. 1 to 5, the present application provides various illumination optical systems applied to appearance inspection, where the optical system includes an imaging module 1, a lens module 2, and an integrated coaxial light source module 3; the imaging module 1, the lens module 2 and the integrated coaxial light source module 3 are sequentially arranged, the imaging module 1 and the lens module 2 are coaxial, and a first central axis L1 of the integrated coaxial light source module 3 is vertical to the central axis of the lens module 2; the integrated coaxial light source module 3 comprises a first light source 31, a first lens 32, a second lens 33 and a third lens 34 which are sequentially arranged in the direction of a first central axis L1, wherein the first lens 32, the second lens 33 and the third lens 34 are all planar lenses; the integrated coaxial light source module 3 further includes a second light source 35 and a fourth lens 36 sequentially arranged in the second axial direction L3, the second lens 32 is further arranged in the second axial direction L3, the fourth lens 36 is arranged on one side of the second lens 32 close to the third lens 34, and the second light source 35 is arranged on one side of the fourth lens 36 departing from the second lens 35; the first axial direction L2 and the second axial direction L3 intersect; illuminating light emitted by the first light source 31 sequentially passes through the first lens 32 and the second lens 33 and then is reflected by the third lens 34 to irradiate the surface of the object 4 to be measured, so that a first path of illuminating light is formed; the illumination light emitted by the second light source 35 passes through the fourth lens 36, is reflected by the second lens 33, is reflected by the third lens 34, and irradiates the surface of the object 4 to be measured to form a second path of illumination light; the illumination light reaching the surface of the object 4 to be measured is reflected by the object 4 to be measured and then sequentially enters the imaging module 1 through the third lens 34 and the lens module 2.

Specifically, as shown in fig. 1 and fig. 2, an imaging module 1 and a lens module 2 which are coaxially arranged are adopted, and the imaging module 1 can adopt a high-speed camera to acquire an image of the surface of an object to be measured 4; the lens module 2 can adopt a Telecentric lens, the Telecentric lens (Telecentric) is mainly designed for correcting the parallax of the traditional industrial lens, and the obtained image magnification ratio can not be changed in a certain object distance range, so that the lens module is very important to be applied to the condition that a measured object is not on the same object plane; telecentric lenses have been favored for machine vision applications where lens distortion requirements are high due to their unique parallel light path design.

Specifically, as shown in fig. 3, the first light source 31, the first lens 32, the second lens 33, and the third lens 34 are sequentially disposed along a first central axis L1 direction of the integrated coaxial light source module 3, where the first lens 32, the second lens 33, and the third lens 34 are all planar lenses, and if the plane of the first lens 32 is perpendicular to the first axis direction L1, an included angle between the plane of the second lens 33 close to the third lens 34 and the first axis direction is 45 °, an included angle between the plane of the third lens 34 close to the second lens 33 and the first axis direction is 45 °, the first path of illumination light is implemented, and the first path of illumination light is divergent coaxial light. Fig. 3 is a schematic structural diagram of the integrated coaxial light source module in the direction of the imaging module shooting the surface of the object to be measured in a downward direction. Referring to fig. 3 and (a) in fig. 4, when the first path of illumination light is used for illumination, the illumination light sequentially passes through the first lens 32 and the second lens 33 and then is reflected by the third lens 34 to form divergent coaxial light which is irradiated on the surface of the object to be measured 4, the divergent coaxial light sequentially passes through the third lens 34 and the lens module 2 after being reflected by the surface of the object to be measured 4 and then enters the imaging module 1, and the imaging module 1 generates image information of the surface of the object to be measured 4.

Continuing with fig. 3, along the second axial direction L3, a second light source 35 and a fourth lens 36 are disposed on one side of the plane of the second lens 33 close to the third lens 34, for example, an included angle between the plane of the fourth lens 36 close to the second lens 33 and the plane of the second lens 33 is 45 °, so as to implement a second path of illumination light, where the second path of illumination light is parallel coaxial light. Preferably, the first axial direction L2 and the second axial direction L3 are orthogonal. Referring to fig. 3 and (b) in fig. 4, when the second path of illumination light is used for illumination, the second light source 31 on one side of the fourth lens 36 is started for illumination, the illumination light emitted by the light source of the second light source 31 passes through the fourth lens 36, is reflected by the second lens 33, is reflected by the third lens 34, forms parallel coaxial light, and is irradiated on the surface of the object to be measured 4, the parallel coaxial light is reflected by the surface of the object to be measured 4, and then enters the imaging module 1 through the third lens 34 and the lens module 2, and the imaging module 1 generates image information of the surface of the object to be measured 4.

The object 4 to be measured is an electronic product housing, and the image acquisition and detection of the surfaces of other materials are not shown here.

In conclusion, the multiple illumination optical systems provided by the application apply multiple illumination modes to the same set of optical system by reasonably designing the structure and the position of the illumination light source in the optical system, and take pictures by using the high-speed camera, so that the function of detecting multiple appearance defects by using a single imaging system at a high speed is realized, the cost and the occupied area of detection equipment are reduced, and the detection efficiency is improved.

In one possible embodiment, referring to fig. 3, the first light source 31 includes a plurality of light sources, and the second light source 35 includes a light source; the light source comprises a light emitting diode, the size of the light emitting diode is C, and C is more than 0 and less than or equal to 3mm multiplied by 3mm. Specifically, in the first path of illumination light, the first light source 31 employs a plurality of light emitting diodes (LED sources), and the plurality of light emitting diodes may be arranged in an array to form a surface light source, or arranged linearly to form a linear light source; in the second path of illumination light, the second light source 35 adopts a light emitting diode, and the size of the light emitting diode is less than or equal to 3mm × 3mm, so that uniform illumination is provided, and the imaging effect of the heterochromatic defect on the surface of the object to be measured is improved.

In one possible embodiment, as shown in fig. 1 to 4, the refractive index of the first lens 32 is n1, and the abbe number of the first lens 32 is V1; the refractive index of the second lens 33 is n1, and the abbe number of the second lens 33 is V1; the refractive index of the third lens 34 is n3, and the abbe number of the third lens 34 is V3; the refractive index of the fourth lens 36 is n4, and the abbe number of the fourth lens 36 is V4; wherein n1 is more than 1.461 and less than 1.650, and V1 is more than 40 and less than 70; n2 is more than 1.461 and less than 1.650, and V2 is more than 40 and less than 70; n3 is more than 1.461 and less than 1.650, V3 is more than 40 and less than 70; n4 is more than 1.461 and less than 1.650, and V4 is more than 40 and less than 70.

Specifically, the refractive index is the ratio of the propagation speed of light in vacuum to the propagation speed of light in the medium, and is mainly used to describe the refractive power of materials to light, and the refractive indices of different materials are different. The larger the refractive index is, the stronger the refractive power of the material to light is; conversely, the smaller the refractive index, the weaker the refractive power of the material to light. The abbe number is an index to express the dispersion ability of the transparent medium; the smaller the Abbe number is, the more severe the dielectric dispersion is; conversely, the larger the Abbe number, the more slight the dispersion of the medium.

Specifically, by reasonably selecting the refractive indexes of the first lens 32, the second lens 33, the third lens 34 and the fourth lens 36, when the first path of illumination light is used for illumination, the illumination light emitted by the first light source 31 sequentially passes through the first lens 2 and the second lens 33 and then is reflected to the surface of the object 4 to be measured by the third lens 34, so that the utilization efficiency of the illumination light can be improved; when the second path of illumination light is used for illumination, the illumination light emitted by the second light source 35 passes through the fourth lens 35, is reflected by the second lens 33, and is reflected to the surface of the object 4 to be measured by the third lens 34, so that the light utilization efficiency of the illumination light is improved. The abbe numbers of the first lens 32 and the second lens 33 are reasonably selected, so that the dispersion of the first lens 2, the second lens 33, the third lens 34 and the fourth lens 35 to the illumination light can be reduced in the illumination light transmission process, the single imaging background of the heterochromatic defect is ensured, and the imaging effect of the surface of the object to be measured is improved.

In one possible embodiment, as shown in FIG. 3, the first lens 32 includes a diffuser plate having a transmittance T, T ≧ 70%. The first lens 32 is a planar diffusion plate, which can also be called a diffusion plate, and the first lens 32 has a light diffusion (diffusing) function, so that the illumination light can be uniformly diffused; meanwhile, the transmittance T of the first lens 32 is set to be greater than or equal to 70%, so that the emergent efficiency of the illumination light is ensured, and the imaging effect of the surface of the object to be measured is improved.

In a possible embodiment, as shown in fig. 3, the second lens 33 is coated with a first light splitting film, and the light splitting wavelength of the first light splitting film is 400nm to 700nm; the surface of the third lens 34 is plated with a second light splitting film, and the light splitting wavelength of the second light splitting film is 400 nm-700 nm; the ratio of the transmittance to the reflectivity of the first light splitting film and the ratio of the transmittance to the reflectivity of the second light splitting film are adjustable.

Specifically, as shown in fig. 3, a first light splitting film with a light splitting wavelength range of 400nm to 700nm is additionally coated on the surface of the second lens 33, so that the illumination light emitted from the first light source 31 can be transmitted to the third lens 34, and the illumination light emitted from the second light source 35 can be reflected to the third lens 34, thereby realizing two-path coaxial light source illumination; meanwhile, a second light splitting film with the light splitting wavelength range of 400 nm-700 nm is additionally plated on the surface of the third lens 34, so that the illuminating light reaching the surface of the third lens 34 can be reflected to reach the surface of the object to be measured 4, and the light reflected by the surface of the object to be measured 4 can be transmitted to enable the light to reach the imaging module 1 through the lens module 2. The ratio of the transmittance and the reflectivity of the first light splitting film to the illuminating light and the ratio of the transmittance and the reflectivity of the second light splitting film to the illuminating light and the surface reflection light of the object to be measured 4 can be adjusted according to practical application.

In addition to the above embodiments, the ratio of transmittance to reflectance of the first dichroic film is 7; the transmittance and reflectance ratio of the second dichroic film is 5. The ratio of the transmittance and the reflectivity of the first light splitting film on the surface of the second lens 33 to the illumination light is set to be 7, and the ratio of the transmittance and the reflectivity of the second light splitting film on the surface of the third lens 34 to the illumination light and the light reflected by the surface of the object 4 is set to be 5.

In one possible embodiment, as shown in fig. 3 and 4, the fourth lens 36 includes a Fresnel lens (Fresnel lens), and the distance between the Fresnel lens and the fourth lens 36 is adjustable.

Specifically, the fourth lens 36 adopts a fresnel lens to collimate and focus the illumination light emitted from the second light source 45, and has a cone coefficient of-1, a 2-order term coefficient of-9.187E-004, and a 4-order term coefficient of-1.400E-006. wherein-9.187E-004 indicates that the 2 nd order coefficient of the Fresnel lens sphere is-9.187 x 10 ^-4 And so on. The collimation degree of the illumination light is adjusted by adjusting the distance between the Fresnel lens and the fourth lens 36, so that parallel coaxial light paths shown in (b) in fig. 5 are formed, and the imaging quality of the surface of the object to be measured is improved.

In one possible embodiment, as shown in FIG. 1 and FIG. 2, the imaging module 1 comprises a camera (camera), the pixel size of the camera is A, the frame rate of the camera is B, A is less than or equal to 3.45um × 3.45um, and B is greater than or equal to 23fps.

Specifically, a 500-thousand high-speed camera is selected, the maximum pixel size A is 3.45um multiplied by 3.45um, the frame rate B is more than or equal to 23fps, and the detection accuracy and the detection efficiency of the micro defects on the surface of the object to be detected can be improved. Among them, the common terminology in the field of cameras, frame rate (rate) is the frequency (rate) at which bit images in units of Frames appear continuously on a display, and Frame Per Second (FPS) is also understood as the so-called "refresh rate (in Hz), which is the same term as applied to film and video cameras, computer graphics, and motion capture systems.

In one possible embodiment, as shown in fig. 1 and fig. 2, the distance between the end surface of the third lens 34 close to the object to be measured and the surface of the object to be measured is 55 ± 2mm.

In a possible implementation manner, as shown in fig. 1 and fig. 2, the lens module 2 includes a 0.3-time telecentric lens, and a distance between an end surface of the 0.3-time telecentric lens close to the object to be measured and a surface of the object to be measured is 100 ± 2mm.

Specifically, as shown in fig. 1 and fig. 2, a 500-thousand high-speed camera and a 0.3-time telecentric lens 2 are assembled together, a first central axis L1 of an integrated coaxial light source module 3 is perpendicular to a central axis L2 of the 0.3-time telecentric lens, a distance D1 between an end surface of a third lens 34 close to an object to be measured and a surface of the object to be measured is 55 ± 2mm, a distance D2 between an end surface of the 0.3-time telecentric lens 2 close to the object to be measured and the metal surface is 110 ± 2mm, and the camera has the best imaging effect when light path illumination is performed by respectively adopting the first path of illumination light illumination and the second path of illumination light illumination.

On the basis of the above embodiments, as shown in fig. 1 and fig. 2, the multiple illumination optical systems further include a light control module 5, where the light control module 5 is electrically connected to the first light source 31 and the second light source 35 respectively, and controls the first light source 31 and the second light source 35 to alternately emit light.

Specifically, the light control module 5 includes a light source controller, which is electrically connected to the light sources in the first light source 31 and the second light source 35, and controls the light source in the first light source 31 to emit light when the first path of illumination light is used for illumination; when the second path of illumination light is used for illumination, the light source in the second light source 35 is controlled to emit light.

A specific example is listed below, and as shown in fig. 2-fig. 5 and tables 1 and 2, in the optical system provided in the embodiment of the present application, a 500 ten thousand high-speed camera 1 and a 0.3-time telecentric lens 2 are adopted to be assembled together, a distance between an end surface of the third lens 34 close to the object to be measured and a surface of the object to be measured is 55 ± 2mm, and a distance between an end surface of the 0.3-time telecentric lens close to the object to be measured and the surface of the object to be measured is 100 ± 2mm. When the first path of illumination light is used for illumination, the light source controller controls the light source in the first light source 31 to emit light, and controls the light source in the second light source 35 to be turned off.

Table 1 shows the optical physical parameters of the elements illuminated by the first illumination beam

Number of noodles	Radius of curvature/R	thickness/T	Refractive index/nd	Abbe number/V
					Light source/LED source	Infinty	10.000
1/32/Diffuser	Infinty	2.000	1.517	64.167
					2	Infinty	28.000
3/33	Infinty	2.000	1.517	64.167
					4	Infinty	60.000
5/34	Infinty	2.000	1.517	64.167
					6	Infinty	55.000
IMA	Infinty	0.000

In table 1, surface numbers are numbered according to the surface sequence of each lens, where surface number 1 represents a surface of the first lens 32 close to the first light source 31, surface number 2 represents a surface of the first lens 32 close to the second lens 33, surface number 3 represents a surface of the second lens 33 close to the first lens 32, surface number 4 represents a surface of the second lens 33 close to the third lens 34, surface number 5 represents a surface of the third lens 34 close to the second lens 33, and surface number 6 represents that the third lens 34 is close to the surface of the object, where surface number 5 and surface number 6 are the same surface of the third lens 34; r is curvature radius representing the bending degree of the surface of the lens, a positive value represents that the surface is bent to one side of an image surface, a negative value represents that the surface is bent to one side of an object surface, and Infinity is infinity, namely a plane; t is thickness, which represents the distance from the current surface to the central axis of the next surface, and the unit of curvature radius and thickness is millimeter (mm); n is a refractive index, a blank space represents that the current position is air, and the refractive index is 1; v is the Abbe number, a blank space represents that the current position is air, and the Abbe number is 0; IMA is the image plane. In table 1, parameters of the camera, the lens, and the light source may be adjusted according to actual conditions, and are not limited to the above.

When the second path of illumination light is used for illumination, the light source controller controls the light source in the second light source 35 to emit light, and controls the light source in the first light source 31 to be turned off.

Table 2 shows the optical physical parameters of each element illuminated with the second illumination beam

Noodle sequence number	Radius of curvature/R	thickness/T	Refractive index/nd	Abbe number/V
					Light source/LED source	Infinty	35.000
1/36	Infinty	1.500	1.517	64.167
					2	-19	28.000
3/33	Infinty	2.000	1.517	64.167
					4	Infinty	60.000
5/34	Infinty	2.000	1.517	64.167
					6	Infinty	55.000
IMA	Infinty	0.000

In table 1, surface numbers are numbered according to the surface sequence of the lenses, where surface number 1 represents a surface of the fourth lens 36 close to the second light source 35, surface number 2 represents a surface number 3 represents a surface of the fourth lens 36 close to the second lens 33, surface number 3 represents a surface of the second lens 33 close to the fourth lens 36, and surface number 4 represents a surface of the second lens 33 close to the third lens 34, where surface number 3 and surface number 4 are the same surface of the second lens 34; the surface number 5 represents a surface of the third lens 34 close to the second lens 33, and the surface number 6 represents that the third lens 34 is close to the surface of the object, where the surface number 5 and the surface number 6 are the same surface of the third lens 34.

Fig. 5 (a) is a diagram of a divergent coaxial light-shot watermark picture obtained by a first path of illumination light; fig. 5 (b) is a diagram of a pit picture photographed by parallel coaxial light obtained by the second path of illumination light, and as shown in fig. 2-fig. 5, table 1 and table 2, the working distance of the whole optical system is 110mm, the visual field is 23.5mm × 28.2mm, and a motion photograph is performed at a speed of 200mm/s, so that light emission of divergent coaxial light and parallel coaxial light in a light emission time sequence alternation is realized.

FIG. 6 is a schematic diagram illustrating image stitching effects after the first path of illumination light is used for illuminating and image taking in FIG. 3; fig. 7 is a schematic diagram of image stitching effect after the second path of illumination light is used for illuminating and image taking in fig. 3. Referring to fig. 2 to 7, specifically, after the product to be measured runs to a photographing position and photographs, the camera is triggered to acquire a first frame of image, and meanwhile, the light source controller controls the first light source 31 to be turned on, the second light source 35 to be turned off, and the first path of illuminating light is started to perform divergent coaxial illumination; after the image acquisition is finished, when the product to be detected runs 1/2 image visual field physical displacement, the camera is triggered to take a second frame image for photographing, meanwhile, the light source controller controls the second light source 35 to be turned on, the first light source 31 is turned off, and a second path of illuminating light is started to perform parallel coaxial light illumination; when the product to be detected moves by 1 image physical displacement, triggering the camera again to obtain a third frame of image, controlling the first light source 31 to be turned on and the second light source 35 to be turned off by the light source controller, and starting the first path of illuminating light to perform divergent coaxial light illumination; when the product runs for 3/2 image physical displacement, triggering the camera again to take a fourth frame image, simultaneously controlling the second light source 35 to be started by the light source controller, closing the first light source 31, starting a second path of illuminating light to perform parallel coaxial light illumination, and alternately controlling the first light source 31 and the second light source 35 to be started by the light source controller according to the logic until the image information of the product to be detected is shot, splicing the odd frame images to form an image shown in the figure 6, wherein the figure 6 is the image after the image is taken by adopting divergent coaxial light illumination; the even frame images are stitched to form the image shown in fig. 7, wherein fig. 7 is the image after the image is taken by using parallel coaxial light illumination.

The parameters of the camera, the lens and the light source may be adjusted according to actual conditions, and are not limited to the above.

Furthermore, as can be seen from the diagrams (a) and (b) in fig. 5, different image effects are presented to the same object to be detected by adopting the coaxial light source illumination of the multi-light path combination and the alternate shooting imaging mode of the combination of the telecentric lens and the high-speed camera, the image on the surface of the object to be detected is clear, and the application requirements for detecting different appearance defects are met.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, but that the features of the various embodiments of the invention may be partially or fully coupled to each other or combined and may cooperate with each other and be technically driven in various ways. Numerous obvious variations, rearrangements, combinations, and substitutions will now occur to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims (10)

1. A multi-illumination optical system applied to appearance detection is characterized by comprising an imaging module, a lens module and an integrated coaxial light source module;

the imaging module, the lens module and the integrated coaxial light source module are sequentially arranged, the imaging module is coaxial with the lens module, and a first central axis of the integrated coaxial light source module is vertical to a central axis of the lens module;

the integrated coaxial light source module comprises a first light source, a first lens, a second lens and a third lens which are sequentially arranged in a first axial direction, wherein the first lens, the second lens and the third lens are planar lenses; the integrated coaxial light source module further comprises a second light source and a fourth lens which are sequentially arranged in the direction of a second axis, and the second lens is also arranged in the direction of the second axis; the fourth lens is positioned on one side of the second lens close to the third lens, and the second light source is positioned on one side of the fourth lens away from the second lens; the first axial direction and the second axial direction intersect;

illuminating light rays emitted by the first light source sequentially penetrate through the first lens and the second lens and then are reflected by the third lens to irradiate the surface of an object to be measured to form a first path of illuminating light rays; the illumination light emitted by the second light source penetrates through the fourth lens, is reflected by the second lens and then is reflected by the third lens to irradiate the surface of the object to be measured, so that a second path of illumination light is formed; and the illumination light reaching the surface of the object to be measured is reflected by the object to be measured and then sequentially penetrates through the third lens and the lens module to enter the imaging module.

2. The illumination-diverse optical system according to claim 1, wherein the first light source includes a plurality of light sources, and the second light source includes a light source;

the light source comprises a light emitting diode, and the size of the light emitting diode is C, wherein C is more than 0 and less than or equal to 3mm multiplied by 3mm.

3. The illumination optical system according to claim 1, wherein the refractive index of the first lens is n1, and the abbe number of the first lens is V1; the refractive index of the second lens is n1, and the Abbe number of the second lens is V1; the refractive index of the third lens is n3, and the Abbe number of the third lens is V3; the refractive index of the fourth lens is n4, and the Abbe number of the fourth lens is V4;

wherein n1 is more than 1.461 and less than 1.650, and V1 is more than 40 and less than 70; n2 is more than 1.461 and less than 1.650, V2 is more than 40 and less than 70; n3 is more than 1.461 and less than 1.650, and V3 is more than 40 and less than 70; n4 is more than 1.461 and less than 1.650, and V4 is more than 40 and less than 70.

4. The illumination optical system according to claim 1, wherein the first lens includes a diffuser plate having a transmittance T of 70% or more.

5. The multi-illumination optical system according to claim 1, wherein the second lens is coated with a first light splitting film having a light splitting wavelength of 400nm to 700nm; the surface of the third lens is plated with a second light splitting film, and the light splitting wavelength of the second light splitting film is 400-700 nm;

the ratio of the transmittance to the reflectivity of the first light splitting film and the ratio of the transmittance to the reflectivity of the second light splitting film are adjustable.

6. The illumination optical systems according to claim 5, wherein the first dichroic film has a transmittance-to-reflectance ratio of 7; the transmittance-reflectance ratio of the second dichroic film is 5.

7. The illumination optical system according to claim 1, wherein the fourth lens includes a fresnel lens, and a distance between the fresnel lens and the fourth lens is adjustable.

8. The illumination optical systems as claimed in claim 1, wherein the distance between the end surface of the third lens close to the object and the surface of the object is 55 ± 2mm.

9. The illumination optical system according to claim 1, wherein the lens module comprises a 0.3-time telecentric lens, and a distance between an end surface of the 0.3-time telecentric lens close to the object and a surface of the object is 100 ± 2mm.

10. The illumination optical systems according to claim 1, further comprising a light control module electrically connected to the first light source and the second light source, respectively, for controlling the first light source and the second light source to alternately emit light.

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