CN215985709U

CN215985709U - Optical lens surface defect detection device based on dark field microscopic imaging principle

Info

Publication number: CN215985709U
Application number: CN202122351306.XU
Authority: CN
Inventors: 于伟; 马倩; 洪学海; 陈鑫
Original assignee: Institute Of Big Data Cloud Computing Center Of Chinese Academy Shangrao
Current assignee: Institute Of Big Data Cloud Computing Center Of Chinese Academy Shangrao
Priority date: 2021-09-27
Filing date: 2021-09-27
Publication date: 2022-03-08
Anticipated expiration: 2031-09-27

Abstract

The utility model discloses an optical lens surface defect detection device based on a dark field microscopic imaging principle, which is used for optical lens surface defect detection and comprises a machine cabinet with a shielding effect, a reflection light source module and a transmission light source module which are arranged in the machine cabinet and can automatically adjust the height, an industrial camera for collecting optical lens defect images, a light source control module for controlling the two light source modules, a lens clamp for supporting a lens to be detected, a transmission module for transmitting the lens clamp to a lens detection station, and a master control module for overall control and pattern analysis; the transmission detection and the reflection detection of the lens are realized, the detection is more comprehensive, the consistency of analysis results of images of acquired defects of the industrial camera is good, the reliability is high, the height of the light source module can be automatically adjusted, the halo can be removed, and the detection accuracy is improved; the product has high overall automation degree and good reliability, reduces manual participation, effectively reduces the detection cost and greatly improves the detection efficiency.

Description

Optical lens surface defect detection device based on dark field microscopic imaging principle

Technical Field

The utility model relates to optical lens surface defect detection equipment, in particular to an optical lens surface defect detection device based on a dark field microscopic imaging principle.

Background

Optical lenses are indispensable key devices in optical systems. The optical lens can be preliminarily molded only by the cold processing links such as cutting, coarse grinding, polishing, core taking and the like in the processing process. In the process, the surface defects such as scratches, pocks, broken edges and the like are easily formed on the surface of the lens under the influence of external vibration, power grid fluctuation, human interference, cutting edge passivation, uneven grinding and polishing particle size, unclean cleaning and the like. These surface defects can affect the optical performance of the lens and, in turn, the performance of the entire optical system. Therefore, optical lens manufacturers need to detect the surface defects of the lenses after finishing a plurality of processing links of the lenses.

At present, the surface defects of the lenses are mainly detected by adopting a traditional manual detection mode. According to the method, in a dark field environment, detection personnel select a proper transmission or reflection polishing mode according to the detection standard of the surface defects, observe the surface defect condition of a detected area by naked eyes through an optical magnifier of 5-10 times, and judge the type and the grade of the defects according to experience or standard comparison patterns. The method has certain subjectivity, is influenced by factors such as experience, attention and eye fatigue degree of detection personnel, and the stability and reliability of a detection result are difficult to guarantee.

The applicant filed a patent application on 28 th 6 th 2021 with the name: patent application No. 202110716475.0 discloses a method and apparatus for removing halo effect in the detection of surface defects of large curvature optical lens. The patent implements partial automation, but the degree of automation is limited.

SUMMERY OF THE UTILITY MODEL

The utility model provides an optical lens surface defect detection device based on a dark field microscopic imaging principle, which can improve the detection efficiency and reduce the manual participation.

In order to solve the technical problems, the utility model provides an optical lens surface defect detection device based on a dark field microscopic imaging principle, which comprises a machine cabinet with a shielding effect, a transmission light source module and a reflection light source module, wherein the transmission light source module and the reflection light source module are arranged in the machine cabinet, the height of the transmission light source module and the height of the reflection light source module can be automatically adjusted, an industrial camera used for collecting optical lens defect images, a light source control module used for controlling the two light source modules, a lens clamp used for supporting a lens to be detected, a transmission module used for transmitting the lens clamp to a lens detection station, and a master control module used for overall control and pattern analysis.

During implementation, in a detection state, the industrial camera is positioned right above the lens to be detected on the lens clamp, the light source of the transmission light source module is positioned right below the lens to be detected, and the light source of the reflection light source module is positioned right above the lens to be detected.

During implementation, the lens clamp is in a suspended state (namely, a certain distance is reserved between the lens clamp and a dark background) at the lens detection station, the dark background is arranged below the inner side of the cabinet, and the dark background is located outside the field depth range of the industrial camera. Therefore, the patterns shot by the industrial camera are ensured to have no other objects except the lens to be detected and the lens clamp, and the scattered light emitted from the defect part is more obvious. The dark background is positioned outside the field depth range of the industrial camera, so that the dust, reflection and the like on the dark background can be prevented from being imaged on the industrial camera, and the defect identification is prevented from being interfered.

When the system is implemented, the master control module is a computer, and the light source control module is a single chip microcomputer, an embedded system, a PLC (programmable logic controller) or integrated in the computer.

When the reflection light source module is implemented, the reflection light source module comprises a linear motion module with a fixed position, the linear motion module comprises a sliding block capable of vertically moving, and one reflection light source is fixed on the sliding block through a support.

When the light source is implemented, the reflection light source is a diffuse reflection annular light source, and the central line of the diffuse reflection annular light source is superposed with the visual axis of the industrial camera.

When the transmission light source module is implemented, the transmission light source module comprises a linear motion module with a fixed position, the linear motion module comprises a sliding block capable of vertically moving, and one transmission light source is fixed on the sliding block through a support.

In practice, the transmission light source is a diffuse reflection light source.

When the lens clamp is implemented, the lens clamp is of a flat plate structure, and one or more bearing holes matched with the size of the lens to be detected are formed in the main plane of the lens clamp.

In practice, the transfer module includes a limiting portion (a portion or a device for limiting) adapted to the lens holder, and the transfer module has a moving mechanism at least in the horizontal front-back and left-right directions, so that the lens holder can be transferred into or out of the cabinet during transfer.

In practice, the transfer module is a robot arm with gripper fingers for gripping the lens holder.

When the device is implemented, the transmission module further comprises a visual guide mechanism.

In practice, the robotic arm is at least a three-axis robotic arm.

When the conveying module is implemented, the conveying module comprises a base, an upright post fixed on the base, a first connecting block extending out of the side part of the upright post, a first deflection arm with one end rotatably connected to the lower part of the first connecting block, a second deflection arm rotatably connected to the other end of the lower part of the first deflection arm, a mechanical claw rotatably connected to the lower end part of the second deflection arm, and two claw arms which can be folded or unfolded and are arranged at the driving end of the mechanical claw.

The utility model has the beneficial effects that: an optical lens surface defect detection device based on a dark field microscopic imaging principle comprises a machine cabinet, a reflection light source module and a transmission light source module which are arranged in the machine cabinet and can automatically adjust the height, an industrial camera for collecting optical lens defect images, a light source control module for controlling the two light source modules, a lens clamp for supporting a lens to be detected, a transmission module for transmitting the lens clamp to a lens detection station, and a master control module for overall control and pattern analysis, wherein the lens clamp is arranged on the machine cabinet; the automatic lens conveying can be realized through the conveying module, the irradiation switching or the combination of the transmission light source module and the reflection light source module realize the transmission detection and the reflection detection or the combination detection of the lens, the detection is more comprehensive, the consistency of the analysis results of the acquired defect images of the industrial camera is good, the reliability is high, the height of the light source module can be automatically adjusted, the removal of the halation can be realized, and the detection accuracy is improved. The product has high integral automation degree and good reliability, reduces manual participation, reduces the detection cost and improves the detection efficiency in industrial application.

Drawings

In order to more clearly illustrate the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also use the drawings to obtain other drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a reflective light source module according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a transmission light source module according to an embodiment of the present invention;

FIG. 4 is a schematic view of a lens holder and a transfer module according to an embodiment of the utility model;

FIG. 5 is a flow chart of the detection according to an embodiment of the present invention;

fig. 6 is a flow chart showing the current lens analysis of fig. 5 inspection (single lens inspection).

Detailed Description

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, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The utility model discloses an optical lens surface defect detection device based on a dark field microscopic imaging principle, which is shown by referring to fig. 1-6, and the device comprises a machine cabinet 5 with a shielding effect, a reflection light source module 2 and a transmission light source module 1 which are arranged in the machine cabinet 5 and can automatically adjust the height, an industrial camera 3 for collecting optical lens defect images, a light source control module 8 for controlling the two light source modules, a lens clamp 7 for supporting a lens to be detected, a transmission module 4 for transmitting the lens clamp 7 to a lens detection station, and a master control module for overall control and pattern analysis. Can realize the automatic conveying of lens through conveying module 4, the illumination of transmission light source module 1 and reflection light source module 2 switches or combines, realizes that the transmission of lens detects, reflection detection or passes/reflect to combine to detect, detects more comprehensively, and the uniformity of industry camera acquisition defect image analysis result is good, the reliability is high, but light source module automatically regulated height can realize that the halo gets rid of, improves the detection accuracy. The product has high integral automation degree and good reliability, reduces manual participation, reduces the detection cost and improves the detection efficiency in industrial application.

In one embodiment, the industrial camera 3 is located on the lens clamp 7 directly above the lens to be detected, the light source of the transmission light source module 1 is located directly below the lens to be detected, and the light source of the reflection light source module 2 is located directly above the lens to be detected. The light source and the lens are coaxial through the position arrangement, so that the influence of halation is avoided to the maximum extent, the detection accuracy is improved, and the halation removing treatment is easy to carry out when the halation occurs; and provides camera imaging quality.

In one embodiment, during inspection, the lens holder 7 at the lens inspection station is in a suspended state (i.e. spaced from the dark background), and the dark background 6 is disposed inside and below the cabinet 5, and the dark background 6 is located outside the depth of field range of the industrial camera 3. Therefore, the patterns shot by the industrial camera 3 are ensured to have no other objects except the lens to be measured and the lens clamp 7, and the scattered light emitted from the defect part of the lens is more obvious. The dark background 6 is located outside the field depth range of the industrial camera 3, so that dust and reflected light on the dark background 6 can be prevented from imaging on the industrial camera 3, and the interference of defect identification is avoided.

In an embodiment, the general control module may be a computer 9, the computer may implement control, analysis, data processing, imaging, and the like through various software and hardware, and the light source control module 8 is a single chip, an embedded system, a PLC, or integrated in the computer 9 to further reduce the cost. Certainly, the situation of changing the quality is not eliminated, the computer 9 is replaced by a display output module, such as a display screen, etc., the lens defects are identified by manually observing the photos, or the functions of the master control module are integrated into the light source control module 8, and the functions of the master control module and the light source control module 8 are re-divided.

In one embodiment, referring to fig. 2, the reflective light source module 2 includes a fixed linear motion module 2-1, the linear motion module 2-1 includes a vertically movable slider, and a reflective light source 2-2 is fixed on the slider through a bracket 2-3. Preferably, the reflective light source 2-2 is a diffuse reflective annular light source, and the central line of the diffuse reflective annular light source is coincident with the visual axis of the industrial camera 3. This simple structure, height-adjustable realizes keeping suitable interval with the lens, and to big curvature lens, is convenient for shoot at two heights and carries out the halo processing (refer later on, or 202110716475.0 patent). The diffuse reflection annular light source enables the lens to obtain more sufficient and more-angle illumination and improves the reflectivity of the flaw part. And the annular shape avoids forming halo on the lens as much as possible.

In one embodiment, referring to fig. 3, the transmission light source module 1 includes a fixed linear motion module 1-1, the linear motion module 1-1 includes a vertically movable slider, and a transmission light source 1-2 is fixed on the slider through a bracket 1-3. Preferably, the transmission light source 1-2 is a diffuse reflection light source. The structure is simple, the height is adjustable, and the proper distance between the lens and the lens can be kept. The annular light source is subjected to diffuse reflection, so that the lens can obtain more sufficient and more-angle illumination, and the presenting degree of a flaw part is improved.

In one embodiment, the lens holder 7 is a flat plate structure, and one or more supporting holes matched with the size of the lens to be detected are arranged on the main plane of the lens holder. The positioning of one or more lenses can be realized through the structure, the lenses are convenient to circulate in the processing and detecting process, and the safety of the lenses is protected. Especially when a plurality of lenses, improve circulation efficiency.

In one embodiment, the transfer module 4 comprises a position-limiting part (a part or a component for limiting the lens holder 7) adapted to the lens holder 7, and the transfer module 4 is provided with a moving mechanism at least in horizontal front-back and left-right directions, so that the lens holder 7 can be moved into or out of the cabinet 5 during the transfer process. For example, a similar conveying belt mechanism is adopted, and besides the conveying direction, a moving mechanism can be arranged at the transverse position, so that the parallel lenses can be conveniently switched and detected. For example, a double-lead screw slider mechanism movable in the direction X, Y is used. In extreme cases of deterioration, the transfer module 4 may have only one degree of freedom of movement mechanism for serially transferring individual lenses into/out of the cabinet 5 for inspection, but this case does not allow parallel lens transfer and reduces the lens holder 7 load. And the lens holder 7 may even be integral with the transfer module 4, reducing costs, but negatively impacting lens cleaning maintenance and ease of circulation.

In one embodiment, the transfer module 4 is a robot arm with gripper fingers for holding the lens holder 7. The mechanical arm technology is mature and responds quickly, and the applicability and the adjustability are good according to different detection requirements and equipment design adjustment requirements.

In one embodiment, the transport module 4 further comprises a visual guide mechanism. Through the cooperation of the vision guide mechanism, the automatic picking of the lens/lens clamp 7 outside the cabinet 5 can be realized, the input equipment is used for detecting, and the output equipment is used for placing at a proper position after the detection is finished, so that the automation degree is improved.

In one embodiment, the robotic arm is at least a tri-axial robotic arm. Thereby enabling at least automatic lens/lens holder 7 pick up, transfer into/out of the cabinet 5, and position adjustment in one direction.

Referring to fig. 1, an embodiment of the present invention, an optical lens surface defect detecting apparatus based on dark field microscopic imaging principle, mainly includes a cabinet 5, wherein an industrial camera 3, a reflective light source module 2, a transmissive light source module 1, a lens clamp 7, a transmission module 4, a light source control module 8, and a computer 9 are arranged in the cabinet.

Wherein, rack 5: the device is mainly used for shielding external stray light, realizing the observation environment of a dark field, avoiding the interference of other indoor light sources, and fixing equipment.

Wherein, the industrial camera 3: an industrial camera with a microscope lens can be used for collecting optical lens defect images, and the industrial camera 3 is fixed inside the cabinet 5 by a camera support. The bottom of the camera bracket is fixedly connected with the cabinet 5; the inner wall of the cabinet in the field range of the camera is black, namely the observation background of the measured lens is black (a dark background 6 is arranged), so that the interference of stray light is avoided.

Wherein, lens anchor clamps 7 and transmission module 4: the lens detected in the utility model is fixed by using a lens clamp 7, the material of the lens clamp is plastic or metal, and the clamp is provided with a hole matched with the size of the lens, so that one or more lenses can be fixed (the lens clamp 7 can be manufactured according to the situation, and the existing clamps of other lens processing procedures can also be used). The lens holder 7 is transported to the inspection position by the transport module 4. The transfer module 4 is composed of a multi-degree-of-freedom mechanical arm with mechanical claws 4-6 and a driving mechanism thereof. The conveying module 4 can grab the lens clamp 7, control the posture of the clamp and move the clamp to the depth of field range of the industrial camera 3 according to a preset path, so that the lenses 10 in the lens clamp 7 are sequentially imaged on the target surface of the camera, and the lens clamp 7 is placed at a specified position after detection is finished. Certainly, when the conveying module 4 is implemented, other conveying structures such as a conveyor belt with a hollow-out embedding station and the like can also be adopted.

As shown in fig. 2, the reflective light source module 2: in the detection process, the main plane of the detected lens is used as a reference plane and is positioned at the same side of the industrial camera 3, and the movable light source module for reflecting light is provided. According to the utility model, the optimal scheme of the reflection light source 2-2 is a diffuse reflection annular light source, and the central line of the annular light source is coincident with the visual axis of the camera. The light source is fixed on a sliding block of the linear motion module 2-1 through a bracket 2-3, and a base of the linear motion module 2-1 is fixedly connected with the cabinet 5 (or indirectly connected with the cabinet 5 after being connected through a main body of the transmission light source module 1). In the observation process, the relative position of the light source and the measured lens 10 is controlled by controlling the position of the sliding block, and the irradiation angle of the light source is further controlled.

As shown in fig. 3, the transmission light source module 1: in the detection process, the main plane of the lens to be detected is used as a reference plane and is positioned at the opposite side of the industrial camera 3, and a movable light source module for transmitting light is provided. The optimal scheme of the transmission light source 1-2 adopts a diffuse reflection light source. The light source is fixed on a sliding block of the linear motion module 1-1 through a support 1-3, and a base of the linear motion module 1-1 is fixedly connected with the cabinet 5. In the observation process, the relative position of the light source and the measured lens 10 is controlled by controlling the position of the sliding block, and the irradiation angle of the light source is further controlled.

Light source control module 8: is a device for controlling the coordination work of the reflection light source module 2 and the transmission light source module 1. The core control device of the light source control module 8 can be implemented by, but is not limited to, the following types of devices: single chip computer, embedded system, PLC, personal computer, industrial control computer. The main functions of the light source control module 8 include: and switching the light source module according to the type of the lens, controlling the light source to move to a specified height, sending the state of the light source to an upper computer (computer) and the like.

The computer 9: the device is mainly responsible for sending instructions to the industrial camera 3, the transmission module 4 and the light source control module 8, ensuring the coordinated work of all components in the device, and simultaneously analyzing the lens surface image collected by the industrial camera 3 and identifying defects in the image.

As shown in the embodiments of fig. 1, 2, 3, 4, 5 and 6. A dark field microscopic imaging principle-based optical lens surface defect detection device comprises a cabinet 5, an industrial camera 3, a lens clamp 7, a transmission module 4, a reflection light source module 2, a transmission light source module 1, a light source control module 8 and a computer 9.

Firstly, an aluminum profile cabinet 5 with the overall dimension of 1m multiplied by 1m is built, the surface of the cabinet 5 is made of opaque materials to shield stray light, the interference of other indoor light sources is avoided, and meanwhile, the dark field observation environment is realized by combining a black dark background 6 arranged at the bottom in the cabinet 5.

In the present embodiment, the industrial camera 3 lens is a microscope lens. The camera is fixed inside the cabinet by adopting a bracket. The bracket base adopts a die-casting aluminum plate, and black sand blasting is carried out on the surface, so that the interference of reflected light to the lens defect detection environment is avoided. The support base upwards connects the stainless steel screwed pipe, and screwed pipe external diameter 25mm, internal diameter 20mm, wall thickness 4mm, height are 600mm, use solid chromium plating stick to connect camera clamping device on the stainless steel screwed pipe, are convenient for adjust camera reach. The camera clamping device is positioned at the upper half part of the stainless steel threaded pipe and provided with a knob, the height of the camera is convenient to finely adjust, the camera clamping device clamps the camera at a distance of 20-85mm, and the camera is protected by PU materials. The transmission light source module 1 and the reflection light source module 2 are composed of linear motion modules 1-1 and 2-1, supports 1-3 and 2-3 and annular light sources. Bases of the two linear motion modules 1-1 and 2-1 are fixedly connected with the bottom of the cabinet 5 relatively, namely the bases are fixed relative to the cabinet 5, and the annular light source is fixedly connected to sliding blocks of the linear motion modules 1-1 and 2-1 through supports 1-3 and 2-3. The annular light sources are all 24v power supply annular light sources. In order to ensure that the light rays are uniformly transmitted on the measured lens, the central axis of the annular light source is coincided with the visual axis of the industrial camera 3.

In this embodiment, the lens 10 is fixed by the lens holder 7, and the outer contour of the holder is a square with a side length of 8.14cm, and the material of the holder is metal or plastic. The lens holder 7 has holes matching the size of the lens 10, and each holder has 25 holes in 5 rows and 5 columns, which can hold 25 lenses (the number of holes can be individually customized for each holder according to the size of the lens).

In this embodiment, the transfer module 4 employs a five-degree-of-freedom robot and a robot gripper 4-6 for holding the lens holder 7 and transferring the lens holder 7 to the detection position. The transfer module 4 can be modified from a SCARA-configuration table-top robot, with the addition of a fifth axis rotation device, a gripper arm 4-7, and a gripper 4-6 with opening/clamping functions. The shape of the gripper arms 4-7 of the gripper fingers 4-6 is arranged according to the shape of the lens holder 7. (the structure of the transmission module 4 is that a base 4-1, an upright post 4-2 fixed on the base 4-1, a first connecting block 4-3 extending from the side of the upright post 4-2, a first deflection arm 4-4 with one end rotatably connected to the lower part of the first connecting block 4-3, a second deflection arm 4-5 rotatably connected to the other end of the first deflection arm 4-4, a mechanical claw 4-6 rotatably connected to the lower end of the second deflection arm 4-5, and two claw arms 4-7 capable of being folded or unfolded are arranged at the driving end of the mechanical claw 4-6).

Furthermore, the mechanical claw 4-6 can drive the claw arm 4-7 to rotate according to the requirement so as to adjust the included angle between the lens clamp 7 and the light source.

Furthermore, although the light sources of the reflective light source module 2 and the transmissive light source module 1 have the height adjusting function, the height adjusting mechanism in the vertical direction may be included on the transmission module 4/the mechanical arm as required, so as to facilitate the height adjustment of the lens holder 7.

In the detection process, the clamping device ensures that the measured lens is suspended, and no lens or object except the clamp exists in the depth of field range of the industrial camera 3. There are no other objects within the depth of field, including the background. Otherwise, dust and light reflection on the background can affect the observation effect.

In this embodiment, the light source control module 8 is used for controlling the transmission light source module 1 and the reflection light source module 2 and uploading the light source state, and the computer 9 is responsible for coordinating the light source control module 8, the transmission module 4, the lens clamp 7 and the industrial camera 3 to work in coordination and analyzing the collected images of the lens 10.

When this patent is implemented, as shown in fig. 5, the detection flow is:

1. the operator selects the lens type, the gripper type in the human-machine interface of the computer 9 application software.

2. The computer 9 sends an instruction to the light source control module 8, the transmission light source module 1 or the reflection light source module 2 is opened according to the type selection of the lens, the light source is moved to the corresponding height, and the relevant parameters of the lens clamp 7 are loaded;

3. placing the lens clamp 7 on a platform to be detected, moving the mechanical arm of the conveying module 4 to a corresponding position, and automatically grabbing the lens clamp 7 by the claw arm 4-7 of the mechanical claw 4-6;

4. after grabbing the lens clamp 7, the lens clamp 7 is moved to the position to be measured in front of the industrial camera 3 through a preset path, so that the first lens is imaged at the center of the target surface of the camera.

5. The computer 9 analyzes the lens images collected by the industrial camera 3, identifies surface defects therein according to the detection standard, stores the defect information and displays the defect information in the human-computer interaction interface.

6. And after the first lens is detected, moving the mechanical arm according to the information of the lens clamp 7, sequentially moving other lenses in the clamp to the position to be detected, and repeating the step 5 to detect the defects. After all the lens inspection is completed, the conveying device 4 moves the inspected lens clamp 7 out of the inspection position and places the inspected lens clamp in a designated position. (judge whether last lens on the anchor clamps, if move next lens to the position of awaiting measuring, if move anchor clamps out.)

In the step 5, when the lens to be measured is a large-curvature lens, under the irradiation of the reflective light source 2-2, the defect surface has a halo, and the reflective light source 2-2 needs to be placed at different heights to take two pictures, and then the halo is eliminated by using an image processing method. This step can be divided into the following 10 sub-steps, detailed in the single lens analysis sub-flow shown in fig. 6:

(1) turning on the transmission light source 1-2, and moving the transmission light source to a preset observation position;

(2) the industrial camera 3 shoots an image of the surface of the lens under the irradiation of the transmission light source 1-2 to obtain a picture P1;

(3) the computer 9 analyses the picture P1 to identify surface defects therein;

(4) turning off the transmission light source 1-2 and moving it to the starting position;

(5) turning on the reflection light source 2-2 and moving it to the irradiation position A;

(6) taking an image of the lens surface to obtain a picture P2;

(7) moving the reflective light source 2-2 to the irradiation position B;

(8) taking an image of the lens surface to obtain a picture P3;

(9) merging and analyzing the pictures P2 and P3, eliminating the influence of halation and identifying surface defects;

(10) and (5) integrating the analysis results of the step (3) and the step (9), and recording and displaying.

In the implementation, the method of combining and analyzing the pictures P2 and P3 in the step (9) is further expanded, which can refer to a method and a device for removing the influence of halo in the surface defect detection of a large-curvature optical lens with application number 202110716475.0, and the method flow is as follows:

step one, on the basis of a dark field scattering microscopic imaging method, selecting two different heights for an illumination light source to ensure that when the light source is illuminated at the two heights, halos on the surface of a lens can be staggered;

step two, respectively shooting pictures P2 and P3 of the tested lens when the light source is at the two heights;

and step three, eliminating the halo part in a covering mode to obtain a lens surface image without the influence of the halo, namely a picture P4.

Preferably, the dark field scattering microscopic imaging method is that the optical lens to be measured is placed below the imaging system in a dark field environment, and the light beam emitted by the illumination system irradiates the surface of the optical lens to be measured; if the surface of the lens has no defects, the illuminating beam is emitted from the other side and does not enter an upper imaging system; when defects exist on the surface of the optical element, due to local microstructures of the defects, the incident light beam generates a large-range scattering, and part of scattered light enters an imaging system, so that a defect bright image under a dark background is obtained.

Preferably, between the second step and the third step, the image needs to be preprocessed to realize the image noise reduction and the position alignment.

Preferably, the third step is specifically: respectively searching for a halo position in two pictures P2 and P3, and then constructing a mask according to the halo shape; meanwhile, the merged picture S is obtained by two different merging methods_maxAnd S_minWherein the picture S_maxTaking the one with the largest gray value in the corresponding pixel in P2 and picture P3 as: s_max(i, j) ═ max (a (i, j), B (i, j)), picture S_minEach pixel in P2 and the one in picture P3 with the smallest gray value among the corresponding pixels: s_min(i, j) ═ min (a (i, j), B (i, j)); using masks and merged picture S_maxAnd S_minCalculating to cover the halation to obtain a picture P4 without the halation; the defect image is extracted from the image P4 by using an image processing method such as edge detection and threshold segmentation, or an artificial intelligence method.

Preferably, the image S is obtained by using a mask and combining_maxAnd S_minCalculating to cover the halation to obtain a picture P4 without the halation; the specific method comprises the following steps: c (i, j) ═ S at halo_min(i, j), other positions C (i, j) ═ S_max(i,j)。

Corresponding to an optical lens surface defect detection device based on a dark field microscopic imaging principle, a light source control module 8 of the device comprises a height control module which is used for adjusting a light source in a reflection light source group 2 to two different heights to take pictures respectively (an industrial camera 3) when the reflection light of a large-curvature optical lens is tested, and the master control module further comprises a halo removing module which is used for combining the pictures taken at the two different heights to remove halos.

The utility model uses the lens clamp to fix the measured lens and uses the mechanical claw clamp to ensure that the measured lens is suspended in the air in the detection process, no other object exists in the depth of field range of the camera, and the background is black, so that the scattered light emitted from the defect part is more obvious. Compared with the prior art that the lens is placed on a non-transparent solid, a glass slide and other carriers, the interference of factors such as uneven surface of the carrier, dust on the surface of the carrier and the like can be avoided.

The movable transmission light source and the movable reflection light source are adopted for polishing, the polishing mode and the polishing angle can be switched, the flexibility is higher for different application scenes, and the better observation effect can be obtained. Defects such as scratches and the like are suitable for combined observation of reflected light and transmitted light; the large-curvature lens can generate halo under the irradiation of reflected light, the observation effect can be influenced, the reflected light source needs to be irradiated twice at different heights, and the influence of the halo is eliminated by an image processing method; the defects such as color spots and the like have better observation effect under the irradiation of reflected light.

The utility model adopts the multi-degree-of-freedom mechanical arm and the mechanical claw to clamp the lens clamp, can adjust the posture of the lens and is convenient for obtaining a better observation angle. In the detection, the scratch has a better observation effect under the irradiation condition of combining the transmitted light and the reflected light, and the color spot has a better observation effect under the observation of the reflected light. This patent has controllable adjustable transmission light source and reflection light source concurrently, can realize automatic optimum detection under light source control module group 8 and total accuse module amount control.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the method, the apparatus and the unit described above may refer to corresponding processes in the foregoing method embodiments, and are not described herein again. Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the examples described in connection with the embodiments disclosed herein may be embodied in electronic hardware, computer software, or combinations of both, and that the components and steps of the examples have been described in a functional general in the foregoing description for the purpose of illustrating clearly the interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

While the utility model has been described with reference to specific embodiments, the utility model is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the utility model. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. The optical lens surface defect detection device based on the dark field microscopic imaging principle is characterized by comprising a shielding cabinet (5), a reflection light source module (2) and a transmission light source module (1) which are arranged in the cabinet (5) and can automatically adjust the height, an industrial camera (3) used for collecting optical lens defect images, a light source control module (8) used for controlling the two light source modules, a lens clamp (7) used for supporting a lens to be detected, a transmission module (4) used for transmitting the lens clamp (7) to a lens detection station, and a master control module used for overall control and pattern analysis.

2. The optical lens surface defect detecting device based on the dark field microscopic imaging principle as claimed in claim 1, wherein in the detecting state, the industrial camera (3) is located on the lens clamp (7) right above the lens to be detected, the light source of the transmission light source module (1) is located right below the lens to be detected, and the light source of the reflection light source module (2) is located right above the lens to be detected.

3. Optical lens surface defect detection device based on dark field microscopic imaging principle according to claim 1 characterized in that said lens holder (7) is in suspended state at said lens detection station, a dark background (6) is provided in said cabinet (5) below, said dark background (6) is located outside the depth of field range of said industrial camera (3).

4. The optical lens surface defect detecting device based on dark field microscopic imaging principle as claimed in any one of claims 1, 2 or 3, characterized in that the general control module is a computer (9), and the light source control module (8) is a single chip microcomputer, an embedded system, a PLC, or integrated in the computer (9).

5. The optical lens surface defect detecting device based on dark field microscopic imaging principle according to any claim 1, 2 or 3, characterized in that the reflective light source module (2) comprises a fixed reflective light source module linear motion module (2-1), the reflective light source module linear motion module (2-1) comprises a vertically movable slide block, and a reflective light source (2-2) is fixed on the slide block through a reflective light source module bracket (2-3); the reflection light source (2-2) is a diffuse reflection annular light source, and the central line of the diffuse reflection annular light source is superposed with the visual axis of the industrial camera (3).

6. The device for detecting surface defects of optical lenses based on the dark field microscopic imaging principle according to any one of claims 1, 2 or 3, wherein the transmission light source module (1) comprises a fixed transmission light source module linear motion module (1-1), the transmission light source module linear motion module (1-1) comprises a vertically movable slide block, and one transmission light source (1-2) is fixed on the slide block through a transmission light source module bracket (1-3); the transmission light source (1-2) adopts a diffuse reflection light source.

7. Optical lens surface defect detection device based on dark field microscopic imaging principle according to any of claims 1, 2 or 3 characterized in that the lens holder (7) is a flat plate structure with one or more bearing holes on its main plane matching the size of the lens to be detected.

8. Optical lens surface defect detection device based on dark field microscopic imaging principle according to any of claims 1, 2 or 3 characterized in that the transfer module (4) comprises a limit part adapted to the lens holder (7) and the transfer module (4) is provided with a moving mechanism at least in horizontal front-back and left-right directions for moving the lens holder (7) into or out of the cabinet (5) during the transfer.

9. The optical lens surface defect detecting device based on dark field microscopic imaging principle according to claim 8, characterized in that the transferring module (4) is a robot arm with a gripper for holding the lens holder (7).

10. The optical lens surface defect detecting device based on dark field microscopic imaging principle as claimed in claim 8, characterized in that said conveying module (4) further comprises a visual guiding mechanism.

11. The apparatus for detecting defects on the surface of an optical lens based on the dark field microscopic imaging principle as claimed in claim 9, wherein said robot is at least a three-axis robot.

12. The dark field microscopic imaging principle-based optical lens surface defect detecting device according to claim 11, wherein the conveying module (4) comprises a base (4-1), a column (4-2) fixed on the base (4-1), a first connecting block (4-3) extending from the side of the column (4-2), a first deflecting arm (4-4) with one end rotatably connected to the lower part of the first connecting block (4-3), a second deflecting arm (4-5) rotatably connected to the lower end of the first deflecting arm (4-4), a mechanical claw (4-6) rotatably connected to the lower end of the second deflecting arm (4-5), and two foldable or unfoldable claw arms (4-7) arranged at the driving end of the mechanical claw (4-6).