CN113219622A - Objective lens focusing method, device and system for panel defect detection - Google Patents
Objective lens focusing method, device and system for panel defect detection Download PDFInfo
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- 241001156002 Anthonomus pomorum Species 0.000 claims description 5
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- 238000004590 computer program Methods 0.000 claims description 3
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- 239000004973 liquid crystal related substance Substances 0.000 description 1
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/28—Systems for automatic generation of focusing signals
- G02B7/36—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/956—Inspecting patterns on the surface of objects
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B13/00—Viewfinders; Focusing aids for cameras; Means for focusing for cameras; Autofocus systems for cameras
- G03B13/32—Means for focusing
- G03B13/34—Power focusing
- G03B13/36—Autofocus systems
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N2021/9513—Liquid crystal panels
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/956—Inspecting patterns on the surface of objects
- G01N2021/95638—Inspecting patterns on the surface of objects for PCB's
Abstract
The invention provides an objective lens focusing method, device and system for panel defect detection, and relates to the technical field of panel detection. The invention discloses an objective lens focusing method for detecting panel defects, which comprises the following steps: determining a focusing layer of a camera objective lens according to the reference panel; moving the camera objective lens to the focusing layer, and acquiring an image of the panel to be detected through a camera; adjusting the distance between the camera objective lens and the panel to be detected so that the camera collects a plurality of images of the panel to be detected; and comparing the definition of the plurality of images, determining the image with the highest definition, and determining the focusing position of the camera objective lens according to the position corresponding to the image with the highest definition. According to the technical scheme, the focusing position of the panel to be detected is determined according to the focusing layer determined by the reference panel, the clear imaging of the mu-level defects is guaranteed, and the defects are correctly classified so as to meet the requirement of panel defect detection.
Description
Technical Field
The invention relates to the technical field of panel detection, in particular to an objective lens focusing method, device and system for panel defect detection.
Background
In the existing panel product detection process, the requirements on the circuit production process inside the panel are strict, and any defects such as short circuit, open circuit, pollution doping, internal circuit structure damage and the like in the circuit are not allowed.
With the development of panel modernization, although the size of products in the fields such as liquid crystal panels is larger and larger, the spacing area between internal circuits is smaller and smaller, so that the difficulty of defect detection on the internal circuits is high. In order to solve the internal tiny defect imaging and simultaneously to solve the defect imaging of different sizes, a plurality of objective lenses with different magnifications are generally adopted as core components of panel optical detection, the depth of field of the objective lenses is smaller when the multiple of the objective lenses is higher, and the depth of field of the objective lenses with 20 times is generally within a range of +/-3 mu, so that the existing manual focusing mode cannot meet the requirement of panel defect detection.
Disclosure of Invention
The invention solves the problem of how to realize the automatic focusing of the objective lens so as to meet the requirement of detecting the defects of the panel.
In order to solve the above problems, the present invention provides an objective focusing method for panel defect detection, comprising: determining a focusing layer of a camera objective lens according to the reference panel; moving the camera objective lens to the focusing layer, and acquiring an image of the panel to be detected through a camera; adjusting the distance between the camera objective lens and the panel to be detected so that the camera collects a plurality of images of the panel to be detected; and comparing the definition of the plurality of images, determining the image with the highest definition, and determining the focusing position of the camera objective lens according to the position corresponding to the image with the highest definition.
The objective lens focusing method for detecting the panel defects determines the focusing position of the panel to be detected according to the focusing layer determined by the reference panel, improves the acquisition coverage rate of the panel to be detected by adjusting the distance between the camera objective lens and the panel to be detected, ensures that mu-level defects can be imaged clearly, and further realizes correct classification of the defects so as to meet the requirements of panel defect detection.
Optionally, the determining the focusing layer of the camera objective lens according to the reference panel comprises: adjusting the position of the camera objective lens to enable the camera to collect a plurality of images of the reference panel; determining an image with the highest definition evaluation score in a plurality of images through an evaluation algorithm; and determining a corresponding focusing position through the image with the highest definition evaluation score so as to determine the focusing layer according to the focusing position.
The objective lens focusing method for detecting the panel defects adopts an image definition evaluation algorithm to determine the clearest position of an image, so that the focusing layer of the camera objective lens is determined according to the reference panel, the focusing position of the panel to be detected is determined according to the focusing layer, the clear imaging of mu-level defects is ensured, and the defects are correctly classified to meet the requirements of panel defect detection.
Optionally, the determining, by an evaluation algorithm, an image with a highest sharpness evaluation score in the plurality of images includes: and determining the image with the highest definition evaluation score by any one evaluation algorithm of a variance method, a Laplace energy evaluation method, an energy gradient evaluation method, a Brenner function evaluation method and a Tenegrad function evaluation method.
According to the objective lens focusing method for detecting the panel defects, disclosed by the invention, the image definition is evaluated through a plurality of definition evaluation algorithms, the algorithm adaptability is enhanced, the image definition judgment accuracy is improved, and thus the focusing position is accurately determined.
Optionally, the adjusting the distance between the camera objective and the panel to be detected includes: moving the camera objective equally spaced from the in-focus layer to cause the camera to capture the images at different positions that are equally spaced.
According to the objective lens focusing method for detecting the panel defects, the camera objective lenses are moved from the focusing layer at equal intervals, so that the camera collects images at different positions at equal intervals, the sampling rate of the images is improved, and the accuracy of the focusing position is improved.
Optionally, said moving said camera objective lens equidistantly from said focal layer comprises: moving the camera objective a preset distance from the in-focus layer to a first position; if the definition of the image at the first position is larger than that of the image at the focusing layer, continuing to move the camera objective lens for the preset distance in the same direction until the definition of the image is smaller than or equal to that of the previous position, and stopping moving the camera objective lens; if the definition of the image at the first position is smaller than the definition of the image at the focusing layer, moving the camera objective lens from the focusing layer to the opposite direction for the preset distance until the definition of the image is smaller than or equal to the definition of the previous position, and stopping moving the camera objective lens.
According to the objective lens focusing method for detecting the panel defects, the images are collected at preset intervals, so that the sampling rate of the images is improved, and the accuracy of focusing position judgment is improved.
Optionally, the objective focusing method for panel defect detection further includes: and determining the type of the camera objective lens selected according to the defect position and the defect area.
The objective lens focusing method for detecting the panel defects determines the types of the selected camera objective lenses according to the defect positions and the defect areas, improves the definition of images and further improves the accuracy of focusing position judgment.
Optionally, the objective focusing method for panel defect detection further includes: and the camera objective lens is automatically switched to be selected through the electronic conversion table.
According to the objective lens focusing method for detecting the panel defects, the electronic conversion table is automatically switched to the selected camera objective lens, so that multi-objective lens automatic focusing is realized without generating virtual images, only one stepping motor is needed during switching, the number of cameras and motors is reduced, and the cost is greatly reduced.
The present invention also provides an objective focusing device for panel defect detection, comprising: the reference module is used for determining a focusing layer of the camera objective lens according to the reference panel; the acquisition module is used for moving the camera objective lens to the focusing layer and acquiring an image of the panel to be detected through the camera; the adjusting module is used for adjusting the distance between the camera objective lens and the panel to be detected so as to enable the camera to collect a plurality of images of the panel to be detected; and the focusing module is used for comparing the definition of the images and determining the image with the highest definition so as to determine the focusing position of the camera objective lens according to the position corresponding to the image with the highest definition. The objective lens focusing device for detecting the panel defects and the objective lens focusing method for detecting the panel defects have the same advantages compared with the prior art, and are not repeated herein.
The invention also provides an objective lens focusing system for detecting panel defects, which comprises a voice coil motor, a first distance measuring sensor, a position encoder and a controller, wherein the voice coil motor, the first distance measuring sensor and the position encoder are respectively and electrically connected with the controller, the distance measuring sensor is used for monitoring the spacing distance between a camera objective lens and a panel to be detected and feeding back the spacing distance to the controller, the position encoder is used for monitoring the position information of the camera objective lens and feeding back the position information to the controller, the voice coil motor is used for driving the camera objective lens to move, and the controller is used for realizing the objective lens focusing method for detecting panel defects. Compared with the prior art, the objective lens focusing system for panel defect detection and the objective lens focusing method for panel defect detection have the same advantages, and are not described herein again.
The present invention also provides a computer-readable storage medium storing a computer program which, when read and executed by a processor, implements the objective lens focusing method for panel defect detection as described above. The computer-readable storage medium has the same advantages as the objective lens focusing method for detecting the panel defects compared with the prior art, and is not described herein again.
Drawings
FIG. 1 is a schematic diagram of an objective lens focusing method for panel defect detection according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a prism reflection according to an embodiment of the present invention;
FIG. 3 illustrates various position sharpness evaluation scores according to an embodiment of the present invention;
FIG. 4 is a block diagram of an objective focusing system for panel defect detection according to an embodiment of the present invention;
FIG. 5 is a bottom view of an objective focusing system for panel defect detection according to an embodiment of the present invention;
FIG. 6 is a side view of an objective focusing system for panel defect detection according to an embodiment of the present invention.
Description of reference numerals:
the detection device comprises a voice coil motor 1, a first distance measuring sensor 2, a position encoder 3, a bottom plate 4, a movable plate 5, a gravity compensation mechanism 6, a guide mechanism 7, a guide movable piece 71, a guide fixed piece 72, a camera objective lens 8 and a panel to be detected 9.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
As shown in fig. 1, an embodiment of the present invention provides an objective focusing method for detecting a panel defect, including: determining a focusing layer of a camera objective lens according to the reference panel; moving the camera objective lens to the focusing layer, and acquiring an image of the panel to be detected through a camera; adjusting the distance between the camera objective lens and the panel to be detected so that the camera collects a plurality of images of the panel to be detected; and comparing the definition of the plurality of images, determining the image with the highest definition, and determining the focusing position of the camera objective lens according to the position corresponding to the image with the highest definition.
Specifically, in the present embodiment, the objective lens focusing method for panel defect detection includes: determining a focusing layer of a camera objective according to a reference panel, generally keeping the horizontal plane of a camera still, selecting a reference panel sample, freely moving the camera up and down, keeping the camera vertical to the horizontal plane of the panel, continuously collecting panel imaging images at different positions, and determining the focusing layer according to the definition of the images; when a camera is focused on a panel to be detected, the camera objective lens is moved to a focusing layer, an image of the panel to be detected is collected through the camera, then the distance between the camera objective lens and the panel to be detected is adjusted, so that the camera collects multiple images of the panel to be detected, the definition of the image collected each time is recorded, the image with the highest definition is determined by comparing the definition of each image, and the position corresponding to the image with the highest definition can be used as the focusing position of the camera objective lens. The reference panel is a focusing standard part, before the panel to be detected is focused, the reference panel is placed near the detection position of the panel to be detected to determine a focusing layer, the focusing layer can be accurately determined through the reference panel, the focusing position of the panel to be detected is determined according to the focusing layer determined by the reference panel, and the camera objective lens can be moved upwards or downwards at certain intervals (for example 1 mu) from the focusing layer by adjusting the distance between the camera objective lens and the panel to be detected, so that the acquisition coverage rate of the panel to be detected is improved, the mu-level defects can be clearly imaged, and the defects can be correctly classified to meet the requirement of detecting the defects of the panel.
The microscopic imaging module between the camera objective lens and the camera is used for imaging, and as shown in fig. 2, the microscopic imaging module can be replaced by a closed prism reflection device (including a light source, a parallel flat plate and a sleeve lens), and the prism reflection scheme is that the light emitted by the flat plate to be measured is emitted for multiple times, and the light source is transmitted to the camera for imaging. Light generated by the light source is reflected by the parallel flat plate, forms radiant light at the measured flat plate, is transmitted to the sleeve lens through the parallel flat plate again, and is collected by the CCD to realize imaging.
In the embodiment, the focusing position of the panel to be detected is determined according to the focusing layer determined by the reference panel, the acquisition coverage rate of the panel to be detected is improved by adjusting the distance between the camera objective and the panel to be detected, the mu-level defect can be clearly imaged, and the defect can be correctly classified to meet the requirement of detecting the panel defect.
Optionally, the determining the focusing layer of the camera objective lens according to the reference panel comprises: adjusting the position of the camera objective lens to enable the camera to collect a plurality of images of the reference panel; determining an image with the highest definition evaluation score in a plurality of images through an evaluation algorithm; and determining a corresponding focusing position through the image with the highest definition evaluation score so as to determine the focusing layer according to the focusing position.
Specifically, in the present embodiment, determining the in-focus layer of the camera objective lens from the reference panel includes: adjusting the position of the camera objective lens to enable the camera to collect a plurality of images of the reference panel, namely continuously collecting panel imaging images at different positions; determining the image with the highest sharpness evaluation score in the plurality of images through an evaluation algorithm, so that the image at which position is the clearest can be determined according to the image with the highest sharpness evaluation score; the corresponding focusing position is determined through the image with the highest definition evaluation score, so that the focusing layer is determined according to the focusing position, the focusing layer of the camera objective lens can be determined according to the reference panel, namely the position of the image with the highest definition evaluation score is collected as the focusing position corresponding to the image, the position is the focusing layer based on the reference panel, the focusing position of the panel to be detected is determined according to the focusing layer, the clear imaging of the mu-level defect is ensured, and the defect is correctly classified to meet the requirement of panel defect detection.
The focusing layer can also be determined by transmitting light waves or radiation waves to the reference panel and then receiving reflected waves of the reference panel to measure the object distance until the object distance is close to the focal length of the objective lens to finish automatic focusing.
In the embodiment, the position with the clearest image is determined by using an image definition evaluation algorithm, so that the focusing layer of the camera objective lens is determined according to the reference panel, the focusing position of the panel to be detected is determined according to the focusing layer, the clear imaging of the mu-level defects is ensured, and the defects are correctly classified to meet the requirement of panel defect detection.
Optionally, the determining, by an evaluation algorithm, an image with a highest sharpness evaluation score in the plurality of images includes: and determining the image with the highest definition evaluation score by any one evaluation algorithm of a variance method, a Laplace energy evaluation method, an energy gradient evaluation method, a Brenner function evaluation method and a Tenegrad function evaluation method.
Specifically, in this embodiment, the determining, by the evaluation algorithm, the image with the highest sharpness evaluation score among the plurality of images includes: and determining the image with the highest definition evaluation score by any one evaluation algorithm of a variance method, a Laplace energy evaluation method, an energy gradient evaluation method, a Brenner function evaluation method and a Tenegrad function evaluation method. The image definition is evaluated through various definition evaluation algorithms, algorithm adaptability is enhanced, and image definition judgment accuracy is improved, so that a focusing position is accurately determined.
Among them, since a sharply focused image has a larger gray difference than a blurred image, a variance function can be used as an evaluation function. The image with clear focus has larger gray difference between its data compared with the image with fuzzy focus, i.e. the variance of the gray data of the image is larger, and the image definition can be measured by the variance of the gray data of the image, and the larger the variance is, the better the definition is.
The method comprises the steps of performing template convolution on an image by utilizing a Laplacian operator to obtain a high-frequency component of the image, then summing the high-frequency components of the image, and using the sum of the high-frequency components as a definition evaluation standard of the image.
The energy gradient function takes the square sum of the difference between the gray values of the adjacent pixels in the x direction and the y direction as the gradient value of each pixel point, and the gradient values of all the pixels are accumulated to be used as a definition evaluation function value.
Among them, the Brenner gradient function is the simplest gradient evaluation function, and the sharpness is evaluated by calculating the square of the gray difference between two adjacent pixels.
The Tenegrad function is a commonly used image definition evaluation function and is a function based on gradient. In image processing, it is generally believed that the in-focus image has sharper edges and therefore larger gradient function values.
In the embodiment, the image definition is evaluated through a plurality of definition evaluation algorithms, so that the algorithm adaptability is enhanced, the image definition judgment accuracy is improved, and the focusing position is accurately determined.
Optionally, the adjusting the distance between the camera objective and the panel to be detected includes: and fixing the panel to be detected and adjusting the position of the camera objective lens.
Specifically, in this embodiment, adjusting the distance between the camera objective lens and the panel to be detected includes: fixing the panel to be detected and adjusting the position of the camera objective. Fixing the panel to be detected, adjusting the position of the camera objective lens, and realizing the determination of the focusing position by moving the camera objective lens. The distance between the camera objective lens and the panel to be detected is adjusted by adjusting the position of the camera objective lens, and images at different positions are collected, so that the image with the highest definition can be determined.
In this embodiment, the distance between the camera objective lens and the panel to be detected is adjusted by adjusting the position of the camera objective lens, and images at different positions are collected, so that an image with the highest definition can be determined.
Optionally, the fixing the panel to be detected, and the adjusting the position of the camera objective lens includes: moving the camera objective equally spaced from the in-focus layer to cause the camera to capture the images at different positions that are equally spaced.
Specifically, in this embodiment, fixing the panel to be detected, and adjusting the position of the camera objective lens includes: the camera objective lens is moved equidistant from the in-focus layer so that the camera captures images at different positions that are equidistant. The camera objective lens can be moved generally upward or downward from the focal layer at regular intervals (e.g., 1 μ) so that the camera captures images at different positions at equal intervals, thereby increasing the sampling rate of the images and thus the accuracy of the focal position.
In the embodiment, the objective lens of the camera is moved at equal intervals from the focusing layer, so that the camera collects images at different positions at equal intervals, thereby improving the sampling rate of the images and further improving the accuracy of the focusing position.
Optionally, said moving said camera objective lens equidistantly from said focal layer comprises: moving the camera objective a preset distance from the in-focus layer to a first position; if the definition of the image at the first position is larger than that of the image at the focusing layer, continuing to move the camera objective lens for the preset distance in the same direction until the definition of the image is smaller than or equal to that of the previous position, and stopping moving the camera objective lens; if the definition of the image at the first position is smaller than the definition of the image at the focusing layer, moving the camera objective lens from the focusing layer to the opposite direction for the preset distance until the definition of the image is smaller than or equal to the definition of the previous position, and stopping moving the camera objective lens.
Specifically, in the present embodiment, moving the camera objective lens equidistantly from the focusing layer includes: moving a camera objective lens from a focusing layer by a preset distance to a first position; if the definition of the image at the first position is larger than that of the image at the focusing layer, continuously moving the camera objective lens for a preset distance in the same direction until the definition of the image is smaller than or equal to that of the previous position, and stopping moving the camera objective lens; and if the definition of the image at the first position is smaller than that of the image at the focusing layer, moving the camera objective lens from the focusing layer to the opposite direction for a preset distance until the definition of the image is smaller than or equal to that of the previous position, and stopping moving the camera objective lens. The images are collected at preset intervals, so that the sampling rate of the images is improved, and the accuracy of the focusing position is improved.
For example, the panel to be detected is focused, for example, by using a 5X objective lens, the objective lens is moved to the focusing layer a, a picture is taken, and the resolution X at this position is calculated. And then moving the objective lens forward (i.e. in the direction of the panel to be detected) for 1 mu, calculating the definition y of the position again, comparing the definition y with the definition x, if y is larger than x, continuing to move the objective lens forward and recording the definition at intervals of 1 mu until the definition is smaller than the definition recorded last time, and at the moment, the definition position recorded last time is the focusing position. And if x is larger than y, moving every 1 mu backward to record the definition of the position until the definition of every 1 mu backward starts to be smaller than the definition recorded last time, and then, the last definition position is a focusing position. As shown in fig. 3, the horizontal axis represents the number of times of acquisition, and the vertical axis represents the sharpness score, and the image acquired at the 6 th time can be regarded as the image with the highest sharpness.
In the embodiment, the images are collected at preset intervals, so that the sampling rate of the images is improved, and the accuracy of the focusing position judgment is improved.
Optionally, the objective focusing method for panel defect detection further includes: and determining the type of the camera objective lens selected according to the defect position and the defect area.
Specifically, in this embodiment, the objective lens focusing method for panel defect detection further includes: and determining the type of the selected camera objective lens according to the defect position and the defect area. The camera objective comprises 5X, 10X and 20X objectives arranged on the electronic conversion table, automatic focusing can be realized by automatically switching the objectives through the electronic conversion table according to actual needs without generating virtual images, only one stepping motor is needed during switching, the number of cameras and motors is reduced, and the cost is greatly reduced; generally, a 5X objective is used for large defects, and a 20X objective is used for small defects.
The high-power objective lens is used, the imaging depth of field of the camera is small due to the limitation of the high-power objective lens, the target to be detected is imaged clearly after the small depth of field is focused automatically, the non-detection area can be imaged in a blurring mode, and the influence of the non-defect area on detection is reduced.
When each objective lens takes a picture, the objective lens, the automatic conversion table and the camera are kept on the same axis, and the repeated positioning precision of the electronic conversion table is within 0.02 degrees each time.
In the embodiment, the type of the selected camera objective lens is determined according to the defect position and the defect area, so that the definition of an image is improved, and the accuracy of the judgment of the focusing position is further improved.
Another embodiment of the present invention provides an objective focusing apparatus for panel defect detection, including: the reference module is used for determining a focusing layer of the camera objective lens according to the reference panel; the acquisition module is used for moving the camera objective lens to the focusing layer and acquiring an image of the panel to be detected through the camera; the adjusting module is used for adjusting the distance between the camera objective lens and the panel to be detected so as to enable the camera to collect a plurality of images of the panel to be detected; and the focusing module is used for comparing the definition of the images and determining the image with the highest definition so as to determine the focusing position of the camera objective lens according to the position corresponding to the image with the highest definition.
Another embodiment of the present invention provides an objective focusing system for panel defect detection, and referring to fig. 4-6 (the Z axis direction indicates "up"), the objective focusing system includes a voice coil motor 1, a first distance measuring sensor 2, a position encoder 3 and a controller, the voice coil motor 1, the first distance measuring sensor 2 and the position encoder 3 are respectively electrically connected to the controller, the distance measuring sensor is configured to monitor a distance between a camera objective 8 and a panel 9 to be detected and feed back the distance to the controller, the position encoder 3 is configured to monitor position information of the camera objective 8 and feed back the position information to the controller, the voice coil motor 1 is configured to drive the camera objective 8 to move, and the controller is configured to implement the objective focusing method for panel defect detection according to the above embodiments.
Optionally, as shown in fig. 4, the objective focusing system for panel defect detection further includes a bottom plate 4 and a movable plate 5, a stator of the voice coil motor 1 is disposed on the bottom plate 4, a mover of the voice coil motor 1 is connected to the movable plate 5, the movable plate 5 is adapted to move relative to the bottom plate 4, and the movable plate 5 is adapted to be disposed with the camera objective 8.
Optionally, the objective focusing system for panel defect detection further includes a gravity compensation mechanism 6, the gravity compensation mechanism 6 is connected to the movable plate 5, and the gravity compensation mechanism 6 is configured to output a constant force opposite to the gravity direction of the camera objective 8.
Optionally, the objective focusing system for panel defect detection further comprises a guiding mechanism 7, wherein the guiding mechanism 7 is used for limiting the moving direction of the movable plate 5 relative to the bottom plate 4.
Since the panel 9 to be detected is up and down fluctuated on the air floating platform, the camera objective 8 should move up and down along with the panel in order to ensure the imaging effect of the camera objective 8, and in order to limit the motion track of the camera objective 8 relative to the bottom plate 4, a guide mechanism needs to be arranged on the bottom plate 4, and the moving direction of the movable plate 5 relative to the bottom plate 4 is limited by the guide mechanism 7, so as to limit the moving direction of the camera objective 8 arranged on the movable plate 5.
Optionally, the guiding mechanism 7 includes a guiding movable member 71 and a guiding fixed member 72, the guiding fixed member 72 is disposed on the bottom plate 4, the guiding movable member 71 is connected to the movable plate 5, and the guiding movable member 71 is adapted to move along an extending direction of the guiding fixed member 72 relative to the guiding fixed member 72.
The extending direction of the guide fixing member 72 is the vertical direction.
Specifically, the guide fixing member 72 is slidably connected to the guide moving member 71, and the guide moving member 71 can only move up and down by the restriction of the guide fixing member 72, so that the guide moving member 71 is connected to the movable plate 5 by disposing the guide fixing member 72 on the bottom plate 4, so that the movable direction of the movable plate 5 with respect to the bottom plate 4 is an up-down direction, thereby defining the movable direction of the camera objective lens 8 as an up-down direction.
Optionally, the guiding fixing member 72 includes two guide rails, the two guide rails are parallel and spaced apart from each other, and the gravity compensation mechanism 6 is disposed between the two guide rails.
Specifically, the gravity compensation mechanism 6 is arranged between the two guide rails, so that the compactness of the whole structure of the automatic focusing device is improved, and the size of the objective lens focusing system for detecting the panel defects is convenient to reduce.
Wherein the guide rail may be an air-floating guide rail as described below.
Optionally, the guide fixing member 72 includes an air-float guide rail, an air film gap is formed between the guide moving member 71 and the air-float guide rail, and the air-float guide rail is disposed on the bottom plate 4.
Specifically, because an air film gap is formed between the guide moving member 71 and the air-floating guide rail, the friction force between the air-floating guide rail and the guide moving member 71 is low, and compared with a traditional contact type transmission mode adopting a linear guide rail, the friction and wear are reduced, and the service life is prolonged; on the other hand, the conventional linear guide has inconsistent deflection deformation at each positioning position, which results in inconsistent positioning accuracy of the movable guide when the movable guide is positioned at a short distance or a long distance, making it difficult to accurately move the camera objective lens 8 to an optimal imaging position. The air-float guide rail has the function of error homogenization, and can realize consistent positioning precision of the movable guide piece when the movable guide piece is positioned at a short distance or a long distance, thereby improving the accuracy of the focusing process of the camera objective lens 8.
Optionally, the guide movable member 71 includes an air bearing, an air film gap is formed between the air bearing and the guide fixed member 72, and the air bearing is connected to the movable plate 5. The same effects as those of the above embodiment can be achieved by this embodiment.
Another embodiment of the present invention provides a computer-readable storage medium storing a computer program, which when read and executed by a processor, implements the objective lens focusing method for panel defect detection as described above.
Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to be within the scope of the present disclosure.
Claims (10)
1. An objective focusing method for detecting a panel defect, comprising:
determining a focusing layer of a camera objective lens according to the reference panel;
moving the camera objective lens to the focusing layer, and acquiring an image of the panel to be detected through a camera;
adjusting the distance between the camera objective lens and the panel to be detected so that the camera collects a plurality of images of the panel to be detected;
and comparing the definition of the plurality of images, determining the image with the highest definition, and determining the focusing position of the camera objective lens according to the position corresponding to the image with the highest definition.
2. The objective focusing method for panel defect detection according to claim 1, wherein said determining a focusing layer of a camera objective according to a reference panel comprises:
adjusting the position of the camera objective lens to enable the camera to collect a plurality of images of the reference panel;
determining an image with the highest definition evaluation score in a plurality of images through an evaluation algorithm;
and determining a corresponding focusing position through the image with the highest definition evaluation score so as to determine the focusing layer according to the focusing position.
3. The objective focusing method for panel defect detection according to claim 2, wherein the determining the image with the highest sharpness evaluation score in the plurality of images by the evaluation algorithm comprises:
and determining the image with the highest definition evaluation score by any one evaluation algorithm of a variance method, a Laplace energy evaluation method, an energy gradient evaluation method, a Brenner function evaluation method and a Tenegrad function evaluation method.
4. The objective focusing method for panel defect inspection according to claim 1, wherein the adjusting the distance between the camera objective and the panel to be inspected comprises:
moving the camera objective equally spaced from the in-focus layer to cause the camera to capture the images at different positions that are equally spaced.
5. The objective focusing method for panel defect detection according to claim 4, wherein said moving the camera objective equidistant from the focusing layer comprises:
moving the camera objective a preset distance from the in-focus layer to a first position;
if the definition of the image at the first position is larger than that of the image at the focusing layer, continuing to move the camera objective lens for the preset distance in the same direction until the definition of the image is smaller than or equal to that of the previous position, and stopping moving the camera objective lens;
if the definition of the image at the first position is smaller than the definition of the image at the focusing layer, moving the camera objective lens from the focusing layer to the opposite direction for the preset distance until the definition of the image is smaller than or equal to the definition of the previous position, and stopping moving the camera objective lens.
6. The objective focusing method for panel defect inspection according to any one of claims 1 to 5, further comprising: and determining the type of the camera objective lens selected according to the defect position and the defect area.
7. The objective focusing method for panel defect inspection according to claim 6, further comprising: and the camera objective lens is automatically switched to be selected through the electronic conversion table.
8. An objective focusing device for panel defect detection, comprising:
the reference module is used for determining a focusing layer of the camera objective lens according to the reference panel;
the acquisition module is used for moving the camera objective lens to the focusing layer and acquiring an image of the panel to be detected through the camera;
the adjusting module is used for adjusting the distance between the camera objective lens and the panel to be detected so as to enable the camera to collect a plurality of images of the panel to be detected;
and the focusing module is used for comparing the definition of the images and determining the image with the highest definition so as to determine the focusing position of the camera objective lens according to the position corresponding to the image with the highest definition.
9. An objective lens focusing system for detecting panel defects is characterized by comprising a voice coil motor (1), a first distance measuring sensor (2), a position encoder (3) and a controller, the voice coil motor (1), the first distance measuring sensor (2) and the position encoder (3) are respectively electrically connected with the controller, the distance measuring sensor is used for monitoring the spacing distance between the camera objective lens (8) and the panel (9) to be detected and feeding back the spacing distance to the controller, the position encoder (3) is used for monitoring the position information of the camera objective lens (8) and feeding back the position information to the controller, the voice coil motor (1) is used for driving the camera objective lens (8) to move, the controller is used for realizing the objective focusing method for panel defect detection as claimed in any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that it stores a computer program which, when read and executed by a processor, implements the objective lens focusing method for panel defect detection according to any one of claims 1 to 7.
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| CN202110294748.7A CN113219622A (en) | 2021-03-19 | 2021-03-19 | Objective lens focusing method, device and system for panel defect detection |
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| WO2023109466A1 (en) * | 2021-12-16 | 2023-06-22 | 苏州镁伽科技有限公司 | Automatic focusing apparatus, panel detection device and method thereof |
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