CN113746996A

CN113746996A - Contact Image Sensor

Info

Publication number: CN113746996A
Application number: CN202110984635.XA
Authority: CN
Inventors: 王虎岩; 席伟腾; 王凤秀; 曹慧俐; 王家重; 王彭通
Original assignee: Weihai Hualing Opto Electronics Co Ltd
Current assignee: Weihai Hualing Opto Electronics Co Ltd
Priority date: 2021-08-25
Filing date: 2021-08-25
Publication date: 2021-12-03
Anticipated expiration: 2041-08-25
Also published as: CN113746996B

Abstract

The present invention provides a contact image sensor. The contact image sensor includes: a frame, including a support frame for forming an accommodating cavity; a light source assembly, at least part of the light source assembly is located in the accommodating cavity, the light source assembly includes a light source for emitting a detection beam; a light diffusing structure is arranged in the accommodating cavity , and the diffuse light structure is located on one side of the light source, and the diffuse light structure has a diffuse reflection surface for diffuse reflection. Based on the principle of diffuse reflection, at least part of the detection beam is diffusely reflected by the diffuse reflection surface to enter the to-be-scanned at different incident angles. Scanning light of the object; the light receiving part includes a lens located in the accommodating cavity and used for converging light. Based on the reflection principle, at least part of the scanning light is reflected by the object to be scanned and then enters the lens. The technical solution of the present invention solves the problem that the contact image sensor in the prior art is prone to uneven image brightness and darkness when scanning the object to be scanned with a bright surface and/or an uneven surface.

Description

Contact image sensor

Technical Field

The invention relates to the technical field of image detection, in particular to a contact type image sensor.

Background

In the field of industrial detection, two methods are mainly adopted, one is an area-array camera (CCD) and various light sources, and the other is a contact type image sensor. The contact type image sensor is linear scanning, and has the advantages of wide breadth, compact structure, space saving, 1:1 imaging, no distortion and the like. However, due to the structural characteristics of the contact image sensor, its application in certain specific places is limited, such as surface detection of bright metal, glass products, vacuum packaging bags, and the like.

In the prior art, when a contact image sensor scans a bright and wrinkled surface of a vacuum packaging bag, because the surface of the vacuum packaging bag has a high reflectivity and light emitted by a light source is emitted from a small light emitting area, that is, light beams directly emitted by the light source have strong directivity, when the light beams emitted by the light source irradiate two different positions of the vacuum packaging bag, since the wrinkles of the surface of the vacuum packaging bag cause unevenness and different curvature radii may occur at the different positions, light rays irradiating the two positions may generate mirror reflection in different directions, light reflected by the mirror surface at one of the two positions may not enter a lens, light rays entering the lens through diffuse reflection are few, and light reflected by the mirror surface at the other of the two positions can enter the lens, and because the vacuum packaging bag surface is more smooth, the major part light ray can reflect to lens with specular reflection's mode in, like this, can appear the condition of comparatively dark after the position scans, and the condition that another position can be comparatively bright, consequently, can cause the uneven problem of image light and shade to influence subsequent data processing.

Disclosure of Invention

The invention mainly aims to provide a contact image sensor to solve the problem that the contact image sensor in the prior art is easy to have uneven brightness of an image when scanning an object to be scanned with bright surface and/or uneven surface.

In order to achieve the above object, the present invention provides a contact image sensor comprising: a frame including a support frame for forming a receiving cavity; the light source assembly is at least partially positioned in the accommodating cavity and comprises a light source for emitting a detection light beam; the diffuse light structure is arranged in the accommodating cavity and is positioned on one side of the light source, the diffuse light structure is provided with a diffuse reflection surface for diffuse reflection, and at least part of detection light beams form scanning light rays which are emitted into an object to be scanned at different incident angles after being diffusely reflected by the diffuse reflection surface based on the diffuse reflection principle; and the light receiving part comprises a lens which is positioned in the accommodating cavity and is used for converging light rays, and at least part of scanning light rays are reflected by the object to be scanned and then enter the lens based on the reflection principle.

Furthermore, the diffuse light structure is connected with the supporting frame, the diffuse reflection surface is an arc surface, and the circle center of the arc surface and the lens are located on two sides of the arc surface.

Further, the center of the arc surface coincides with the focal point of the lens.

Further, the light diffusing structure comprises a diffuser plate or a diffuse reflective coating, the surface of the light diffusing structure facing the light source forming an arc-shaped surface.

Further, the contact image sensor further comprises a support member for supporting the light diffusing structure, and the support member and the support frame are integrally formed or separately arranged.

Further, light source subassembly still includes the PCB board, and at least partial PCB board is located and holds the intracavity, has mounting angle A between the optical axis of PCB board and lens, and wherein, mounting angle A satisfies: a is more than 0 and less than 90 degrees; the light source is positioned on one side of the PCB board facing the light diffusing structure.

Furthermore, the frame also comprises a mounting groove arranged on the supporting frame, the mounting groove is communicated with the accommodating cavity, and part of the PCB is positioned in the mounting groove; or, the light source comprises a plurality of LED chips which are linearly arranged on the PCB.

Further, the light source assembly comprises a PCB arranged on the frame along the horizontal direction, the light source comprises a plurality of LED chips linearly arranged on the PCB, an included angle B is formed between a boundary light beam emitted by the light source and an optical axis of the lens, and the included angle B is larger than an opening angle of the lens.

Further, the light source assembly is positioned on at least one side of the optical axis of the lens, and the contact image sensor comprises two light diffusing structures which are positioned on two opposite sides of the optical axis of the lens.

Furthermore, the frame also comprises a light-transmitting plate which is connected with the supporting frame and is used for scanning light to pass through, the supporting frame and the light-transmitting plate enclose a containing cavity, and the light-transmitting plate, the light source component, the light diffusing structure and the lens are sequentially arranged along the optical axis direction of the lens; or, the light receiving part also comprises a substrate and a photosensitive piece for sensing the scanning light converged by the lens, and the photosensitive piece is arranged on the substrate.

By applying the technical scheme of the invention, a diffuse structure with a diffuse reflection surface is arranged on one side of a light source, so that a detection light beam with certain directivity emitted by the light source can be reflected to all directions by the diffuse reflection surface, namely, the positions irradiated by the detection light beam on the diffuse reflection surface can be subjected to diffuse reflection, each position subjected to diffuse reflection can reflect the detection light beam to all directions, and thus, part of light reflected by the positions can be incident on an object to be scanned to form scanning light, so that the scanned part of the object to be scanned can receive incident light with various angles, namely, the scanning light can be incident on the object to be scanned with different incident angles, and thus, when the object to be scanned moves along a sub-scanning direction, even if the object to be scanned has a bright surface and/or an uneven surface, the scanning light with different angles can be irradiated on the scanned part of the object to be scanned, and scanning light rays with different incidence angles are subjected to diffuse reflection by an object to be scanned, and then a part of light rays enter the lens, so that the problem of uneven brightness of an image can be solved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic structural diagram of a contact image sensor according to a first embodiment of the present invention; and

fig. 2 is a schematic structural diagram of a contact image sensor according to a second embodiment of the present invention.

Wherein the figures include the following reference numerals:

1. a light source assembly; 101. a PCB board; 102. a light source; 3. a frame; 301. an accommodating chamber; 3011. a first bore section; 3013. a third bore section; 3014. a fourth bore section; 31. a support frame; 32. mounting grooves; 4. a light-transmitting plate; 5. a photosensitive member; 6. a substrate; 7. a lens; 8. an object to be scanned; 901. a light diffusing structure; 902. and a support member.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

It should be noted that, in the embodiment of the present invention, the light diffusing structure 901 has a diffuse reflection surface that can diffuse a light beam, so that the light beam can be diffusely reflected, that is, incident light having a certain angle or incident light that are parallel to each other can be emitted at different emission angles after being diffusely reflected by the diffuse reflection surface, so as to be emitted in various directions.

It should be noted that the contact image sensor according to the embodiment of the present invention can be applied to surface detection of objects with good surface reflectivity, such as bright metal, glass products, and vacuum packaging bags.

The inventor knows that a contact image sensor, especially a large-scale contact image sensor, generally uses an LED array light source as a light source, and knows that the LED chips have a certain distance therebetween, and the larger the distance is, the more easily the problem of uneven brightness of the light source is caused, so that a scanned image has bright and dark stripes, and the brighter the object on the surface, the more obvious the bright and dark stripes are. Of course, in the prior art, the light-diffusing film is generally added between the light source and the object to be scanned to solve the above problems, but the application process is increased, and sometimes multiple layers of light-diffusing films are needed to meet the requirement, which increases the process difficulty, and especially for an ultra-long contact image sensor, the application is more difficult, and further, because the light-transmitting effect of the light-diffusing film is poor, the great light source brightness loss is caused, and the use requirement may not be met. Accordingly, embodiments of the present invention provide a contact image sensor capable of solving the above-described problems.

Example one

As shown in fig. 1, a first embodiment of the present invention provides a contact image sensor. The contact image sensor includes a frame 3, a light source assembly 1, and a light diffusing structure 901. Wherein the frame 3 comprises a supporting frame 31 for forming the accommodation cavity 301; at least part of the light source assembly 1 is located in the accommodating cavity 301, and the light source assembly 1 comprises a light source 102 for emitting a detection light beam; the diffuse light structure 901 is arranged in the accommodating cavity 301, the diffuse light structure 901 is positioned on one side of the light source 102, the diffuse light structure 901 is provided with a diffuse reflection surface for diffuse reflection, and based on the diffuse reflection principle, at least part of detection light beams form scanning light rays which are emitted into the object to be scanned 8 at different incident angles after being diffusely reflected by the diffuse reflection surface; the light receiving part comprises a lens 7 which is positioned in the accommodating cavity 301 and used for converging light, and at least part of scanning light is reflected by the object to be scanned 8 and then enters the lens 7 based on the reflection principle.

In the above technical solution, the diffuse structure 901 having the diffuse reflection surface is disposed on one side of the light source 102, so that the probe light beam emitted by the light source 102 and having a certain directivity is reflected by the diffuse reflection surface to all directions, that is, the positions irradiated by the probe light beam on the diffuse reflection surface are all diffusely reflected, and each position where diffuse reflection occurs reflects the probe light beam to all directions, so that a part of the light beam reflected by the position is incident on the object 8 to be scanned to form a scanning light beam, so that the scanned part of the object 8 to be scanned receives incident light beams of various angles, that is, the scanning light beams are incident on the object 8 to be scanned at different incident angles, so that when the object 8 to be scanned moves along the sub-scanning direction, even if the object 8 to be scanned has a bright surface and/or an uneven surface, the scanning light beams of different angles can be irradiated on the scanned part of the object 8 to be scanned, and scanning light rays with different incidence angles are subjected to diffuse reflection by the object to be scanned 8, and then a part of light rays enter the lens 7, so that the problem of uneven brightness of an image can be solved.

Further, the contact image sensor according to the first embodiment of the present invention can be applied to an object to be scanned having a concave-convex surface, an object to be scanned having a bright surface, an object to be scanned having both a bright surface and a concave-convex surface, and a conventional object to be scanned, and thus, the application range of the contact image sensor can be increased. The rugged object to be scanned generally means that the object to be scanned has a wrinkled surface.

Specifically, in the first embodiment of the present invention, the light diffusing structure 901 is located between the lens 7 and the object 8 to be scanned, so that most of the scanning light is incident on the object 8 to be scanned, and the utilization rate of the scanning light is improved.

As shown in fig. 1, in the first embodiment of the present invention, the light diffusing structure 901 is connected to the supporting frame 31, the light diffusing surface is an arc surface, and the center of the arc surface and the lens 7 are located on two sides of the arc surface.

Through the above arrangement, the light diffusing structure 901 with the arc-shaped surface can diffuse most of the detection light beams to the position of the object 8 to be scanned, so that the detection light beams can be prevented from diverging in the left and right directions in fig. 1 after being diffused, and the utilization rate of the detection light beams can be increased, so that more scanning light beams can be emitted to the object 8 to be scanned.

Of course, in an alternative embodiment not shown in the drawings, the diffuse reflection surface may be a plane, or the diffuse reflection surface may be an arc surface protruding in the upper direction in fig. 1, that is, the center of the arc surface is located at one side of the lens.

As shown in fig. 1, in the first embodiment of the present invention, the center of the arc surface coincides with the focal point of the lens 7.

In the above technical solution, the center of the arc surface coincides with the focus of the lens 7, so that a part of light at each position on the diffuse reflection surface is diffusely reflected to the focus position (i.e. the center of the arc surface), that is, the focus position receives incident light at various angles, thus, the part of the object 8 to be scanned at the focal position receives the scanning light beams incident at various angles, and diffusely reflects at least part of the scanning light beams into the lens 7, as the object 8 to be scanned moves in the sub-scanning direction, each position on the object 8 receives scanning light rays incident at various angles, and each position diffusely reflects at least part of the scanning light rays into the lens 7, therefore, the lens 7 can receive the light reflected by each position of the object 8 to be scanned, and clear imaging can be realized, so that the problem of uneven brightness of the image is solved.

It should be noted that, in the first embodiment of the present invention, the center of the arc surface coincides with the focal point, which means that at least a portion of the center of the arc surface overlaps with the focal point.

As shown in fig. 1, in the first embodiment of the present invention, the light diffusing structure 901 includes a diffusion plate or a diffuse reflection coating, and a surface of the light diffusing structure 901 facing the light source 102 forms an arc-shaped surface.

Through the above arrangement, the detection light beam emitted by the light source 102 can enter the diffuse reflection surface of the diffuse reflection structure 901, and when the detection light beam irradiates on the diffuse reflection surface, because the diffuse reflection coating or the diffuse reflection plate has excellent diffuse reflection performance, the detection light beam can be diffusely reflected to all directions, so that scanning light beams which are incident to the object to be scanned 8 at various angles can be formed, and then the scanning light beams which can enter the object to be scanned 8 can also be diffusely reflected to the lens 7, so that the problem that the image scanned by the contact image sensor has uneven brightness can be solved.

Preferably, in the first embodiment of the present invention, the light diffusing structure 901 is a diffuse reflection coating. The diffuse reflection coating capable of generating diffuse reflection is sprayed on the side of the support frame 31 facing the light source 102, which facilitates the processing.

Preferably, in the first embodiment of the present invention, the diffusion plate is a Micro-foamed reflective plate (Micro Cellular PET). The micro-foaming reflector has excellent diffuse reflection performance, so that the detection light beams can be subjected to diffuse reflection to form scanning light beams which are incident to the object 8 to be scanned at various angles.

As shown in fig. 1, in the first embodiment of the present invention, the contact image sensor further includes a support 902 for supporting the light diffusing structure 901, and the support 902 is disposed separately from the support frame 31.

Through the above arrangement, the supporting member 902 can support the diffuse light structure 901, so that the diffuse light structure 901 is mounted on the supporting frame 31, compared with the case that an arc-shaped surface is directly processed on the inner wall surface of the supporting frame 31 where the accommodating cavity 301 is arranged, the manner of processing the supporting member 902 first and processing the arc-shaped surface on the supporting member 902 is simpler, and then the supporting member 902 on which the diffuse light structure 901 is mounted is connected with the supporting frame 31.

Of course, in an alternative embodiment, the supporting member 902 may be integrally formed with the supporting frame 31, that is, an arc-shaped structure with the same curvature as the light diffusing structure 901 is machined on the supporting frame 31.

Preferably, in the first embodiment of the present invention, the supporting member 902 has a circular arc structure, that is, a circular arc structure with an arc surface is separately made, and then the supporting member 902 is connected to the supporting frame 31.

As shown in fig. 1, in a first embodiment of the present invention, the light source assembly 1 further includes a PCB 101, at least a portion of the PCB 101 is located in the accommodating cavity, and a mounting angle a is formed between the PCB 101 and an optical axis of the lens 7, where the mounting angle a satisfies: a is more than 0 and less than 90 degrees; the light source 102 is located on a side of the PCB board 101 facing the light diffusing structure 901.

Through the arrangement, at least part of the detection light beam emitted by the light source 102 can irradiate the light diffusing structure 901, so that the detection light beam is subjected to diffuse reflection on the light diffusing structure 901 to form scanning light rays which are emitted into the object to be scanned 8 in various directions, and the scanning light rays are reflected to the lens 7, and thus the problem that an image scanned by the contact type image sensor is uneven in brightness can be solved.

Specifically, in the first embodiment of the present invention, the light intensity and the uniformity of the scanning light reflected by the light diffusing structure 901 can be adjusted by changing the position and the installation angle a of the light source 102.

As shown in fig. 1, in the first embodiment of the present invention, the frame 3 further includes a mounting groove 32 disposed on the supporting frame 31, the mounting groove 32 is communicated with the accommodating cavity 301, and a portion of the PCB 101 is located in the mounting groove 32.

In the above technical solution, by providing the mounting groove 32, the PCB can be better fixed on the supporting frame 31, so that the light source 102 can be more stably fixed in the accommodating cavity 301.

Specifically, in the first embodiment of the present invention, the mounting groove 32 has an inclined surface, the included angle between the inclined surface and the optical axis of the lens 7 is the same as the mounting angle, and the PCB 101 is connected to the inclined surface, so that the PCB 101 can be mounted on the supporting frame 31 at the mounting angle a.

As shown in fig. 1, in a first embodiment of the present invention, a light source 102 includes a plurality of LED chips, and the plurality of LED chips are linearly arranged on a PCB board 101.

Through the arrangement, the light source 102 can emit a plurality of detection light beams, so that the brightness of the light source 102 can be improved, the light intensity of the light source 102 can be increased, and the scanned image has enough brightness to meet the use requirement.

Preferably, in the first embodiment of the present invention, the LED chip can emit light in any wavelength band.

Preferably, in the first embodiment of the present invention, the plurality of LED chips are linearly arranged along the length direction and/or the width direction of the PCB board 101, respectively, to form an LED chip array. That is, the plurality of LED chips are linearly arranged along the length direction of the PCB 101, and may be a single row or a plurality of rows.

As shown in fig. 1, in a first embodiment of the present invention, a light source assembly 1 is located on at least one side of an optical axis of a lens 7, and a contact image sensor includes two light diffusing structures 901, where the two light diffusing structures 901 are located on opposite sides of the optical axis of the lens 7.

In the above technical solution, by arranging the two light diffusing structures 901, and respectively positioning the two light diffusing structures 901 on two opposite sides of the optical axis of the lens 7, the detection light beams diffusely reflected on the light diffusing surfaces of the two light diffusing structures 901 can enter the object to be scanned 8 from two opposite sides of the lens 7, so as to form scanning light rays entering the object to be scanned 8 at different angles.

Preferably, in the first embodiment of the present invention, the number of the light source assemblies 1 is two, and the two light source assemblies 1 are respectively located at two opposite sides of the optical axis of the lens 7, so that the diffuse reflection surfaces of the two diffuse reflection structures 901 have incident detection light beams, and thus the scanning light beams are incident on the object to be scanned 8 from various directions, so as to solve the problem of uneven brightness of the image scanned by the contact image sensor.

As shown in fig. 1, in a first embodiment of the present invention, the frame 3 further includes a light-transmitting plate 4 connected to the supporting frame 31 and used for passing through scanning light, the supporting frame 31 and the light-transmitting plate 4 enclose an accommodating cavity 301, and the light-transmitting plate 4, the light source assembly 1, the light-diffusing structure 901 and the lens 7 are sequentially arranged along an optical axis direction of the lens 7.

Through the arrangement, the light-transmitting plate 4 and the supporting frame 31 enclose the accommodating cavity 301, so that dust or moisture can be prevented from being attached to the light source 102, and the image quality of a scanned image can be improved.

Preferably, in the first embodiment of the present invention, the supporting frame 31 is made of plastic or metal.

Preferably, in the first embodiment of the present invention, the light-transmitting plate 4 may be made of glass or transparent plastic.

As shown in fig. 1, in the first embodiment of the present invention, the light receiving portion further includes a substrate 6 and a photosensitive element 5 for sensing the scanning light converged by the lens 7, and the photosensitive element 5 is disposed on the substrate 6.

With the above arrangement, the probe beam condensed by the lens 7 can be directly irradiated on the photosensitive member 5, so that an optical signal reflected by the object 8 to be scanned is converted into an electronic signal to form a scanned image.

Specifically, in the first embodiment of the present invention, the light receiving portion includes a plurality of photosensitive members 5, and the plurality of photosensitive members 5 are linearly arranged on the substrate 6. The photosensitive member 5 is a photoelectric conversion chip, and the substrate 6 may be a PCB. In this way, an optical signal reflected by the object 8 to be scanned can be converted into an electronic signal, and a scanned image can be formed.

Specifically, as shown in fig. 1, in the first embodiment of the present invention, the accommodating cavity 301 includes a first hole section 3011, a second hole section and a third hole section 3013 that are sequentially connected and sequentially arranged along the vertical direction, where diameters of the first hole section 3011 and the third hole section 3013 are larger than that of the second hole section, the mounting groove 32 is communicated with the first hole section 3011, the light diffusing structure 901 is located in the first hole section 3011, the lens 7 is located in the second hole section, and the substrate 6 and the light sensing piece 5 are located in the third hole section 3013, so that the light source 102, the light diffusing structure 901, the lens 7, the light sensing piece 5 and the substrate 6 can be sequentially arranged along the vertical direction.

Specifically, in the first embodiment of the present invention, the third hole section 3013 is a stepped hole section, so that the photosensitive member 5 and the substrate 6 can be assembled more easily.

Specifically, in the first embodiment of the present invention, the accommodating chamber 301 further includes a fourth hole section 3014 located between the second hole section and the third hole section 3013, and the diameter of the fourth hole section 3014 is smaller than that of the second hole section, so that a step surface can be formed between the second hole section and the fourth hole section 3014, and the lens 7 is disposed on the step surface. In this way, the lens 7 is easily mounted.

Example two

As shown in fig. 2, in the second embodiment of the present invention, the difference between the second embodiment of the present invention and the first embodiment is that the PCB board 101 of the light source assembly 1 is mounted on the light-transmitting plate 4, and the mounting groove 32 is not formed on the supporting frame 31. The light source assembly 1 includes a PCB 101 disposed on the frame 3 along a horizontal direction, the light source 102 includes a plurality of LED chips linearly disposed on the PCB 101, an included angle B is formed between a boundary light beam emitted from the light source 102 and an optical axis of the lens 7, and the included angle B is greater than an opening angle of the lens.

Through the above arrangement, the utilization rate of the detection beam can be increased, so that most of the detection beam can be incident into the diffuse reflection surface of the diffuse light structure 901 and is reflected to the object to be scanned 8 through the diffuse reflection surface, and thus, the scanning light incident into the object to be scanned 8 can be increased, and the scanned image is clearer.

Specifically, in the second embodiment of the present invention, the intensity and uniformity of the reflected light of the light diffusing structure 901 can be adjusted by adjusting the left and right positions of the light source 102 in fig. 2.

Preferably, in the second embodiment of the present invention, the included angle B > 12 °. In this way, the probe beam emitted by the light source 102 is prevented from directly entering the lens 7, thereby preventing the effect of scanning the image from being affected.

Other structures of the contact image sensor in the second embodiment of the present invention are the same as those in the first embodiment, and are not described herein again.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects: a diffuse light structure with a diffuse reflection surface is arranged on one side of a light source, so that a detection light beam with certain directivity emitted by the light source can be reflected to all directions by the diffuse reflection surface, namely the positions irradiated by the detection light beam on the diffuse reflection surface can be subjected to diffuse reflection, each position subjected to diffuse reflection can reflect the detection light beam to all directions, and thus, part of light reflected by the positions is incident on an object to be scanned to form scanning light rays, so that the scanned part of the object to be scanned can receive incident light with various angles, namely the scanning light rays can be incident on the object to be scanned at different incident angles, therefore, when the object to be scanned moves along a sub-scanning direction, even if the object to be scanned has a bright surface and/or a concave-convex surface, the scanning light rays with different angles can be irradiated on the scanned part of the object to be scanned, and part of the scanning light rays with different incident angles enter a lens after being subjected to diffuse reflection by the object to be scanned, therefore, the problem of uneven brightness of the image can be solved.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A contact image sensor, comprising:

a frame (3) comprising a support frame (31) for forming a housing cavity (301);

a light source assembly (1), at least part of the light source assembly (1) being located within the receiving cavity (301), the light source assembly (1) comprising a light source (102) for emitting a probe light beam;

the diffuse light structure (901) is arranged in the accommodating cavity (301), the diffuse light structure (901) is positioned on one side of the light source (102), the diffuse light structure (901) is provided with a diffuse reflection surface for diffuse reflection, and at least part of the detection light beams form scanning light rays which are emitted into an object to be scanned (8) at different incident angles after being diffusely reflected by the diffuse reflection surface based on the diffuse reflection principle;

the light receiving part comprises a lens (7) which is positioned in the accommodating cavity (301) and used for converging light, and at least part of scanning light is reflected by the object to be scanned (8) and then enters the lens (7) based on the reflection principle.

2. The contact image sensor according to claim 1, wherein the light diffusing structure (901) is connected to the support frame (31), the light diffusing surface is an arc-shaped surface, and the center of the arc-shaped surface and the lens (7) are located on two sides of the arc-shaped surface.

3. A contact image sensor according to claim 2, characterized in that the centre of the arc-shaped surface coincides with the focal point of the lens (7).

4. A contact image sensor according to claim 2, characterized in that the light diffusing structure (901) comprises a diffuser plate or a diffuse reflective coating, the surface of the light diffusing structure (901) facing the light source (102) forming the curved surface.

5. The contact image sensor according to claim 2, further comprising a support (902) for supporting the light diffusing structure (901), wherein the support (902) is integrally formed with or separate from the support frame (31).

6. The contact image sensor according to any one of claims 1 to 5, wherein the light source assembly (1) further comprises a PCB (101), at least a portion of the PCB (101) being located within the receiving cavity (301), the PCB (101) having a mounting angle A with an optical axis of the lens (7), wherein the mounting angle A satisfies: a is more than 0 and less than 90 degrees;

the light source (102) is located on a side of the PCB board (101) facing the light diffusing structure (901).

7. The contact image sensor according to claim 6, wherein the frame (3) further comprises a mounting groove (32) provided to the support frame (31), the mounting groove (32) communicating with the receiving cavity (301), a portion of the PCB board (101) being located in the mounting groove (32); alternatively, the light source (102) comprises a plurality of LED chips arranged linearly on the PCB board (101).

8. The contact image sensor according to any one of claims 1 to 5, wherein the light source assembly (1) comprises a PCB (101) disposed on the frame (3) along a horizontal direction, the light source (102) comprises a plurality of LED chips linearly arranged on the PCB (101), and an angle B is formed between a boundary light beam emitted by the light source (102) and an optical axis of the lens (7), and the angle B is larger than an opening angle of the lens.

9. A contact image sensor according to any of claims 1 to 5, characterized in that the light source assembly (1) is located on at least one side of the optical axis of the lens (7), the contact image sensor comprising two of said light diffusing structures (901), the two light diffusing structures (901) being located on opposite sides of the optical axis of the lens (7).

10. The contact image sensor according to any one of claims 1 to 5, wherein the frame (3) further comprises a light-transmitting plate (4) connected to the supporting frame (31) and used for passing the scanning light, the supporting frame (31) and the light-transmitting plate (4) enclose the accommodating cavity (301), and the light-transmitting plate (4), the light source assembly (1), the light-diffusing structure (901) and the lens (7) are sequentially arranged along an optical axis direction of the lens (7); or, the light receiving part further comprises a substrate (6) and a photosensitive piece (5) for sensing the scanning light converged by the lens (7), and the photosensitive piece (5) is arranged on the substrate (6).