What is AOI system automatic integration technology?

Source:我的网站      Tiem:2020-12-04 18:32:00

AOI system integration technology involves key components, system design, machine integration, software development, etc. The indispensable key components in the AOI system are image sensor (camera), lens, light source, acquisition and preprocessing card, computer (industrial computer, server), etc. Image sensors are commonly used in various models of CMOS/CCD cameras. The combination of image sensor, lens and light source constitutes the sensing unit in most automatic optical inspection systems. The selection and configuration of components need to be designed and selected according to the inspection requirements. .


The selection of the light source (color, wavelength, power, lighting method, etc.), in addition to distinguishing and enhancing features, also needs to consider the sensitivity range of the image sensor to the light source spectrum. The selection of the lens needs to consider the field of view, depth of field, resolution and other optical parameters. The optical resolution of the lens must match the spatial resolution of the image sensor in order to achieve the price-performance ratio. Generally, the optical resolution of the lens is slightly higher than the spatial resolution of the image sensor, and black-and-white cameras are used as much as possible to improve imaging resolution. The image sensor (camera) adopts area array or linear array to be determined according to the specific situation. The factors that need to be considered when selecting the type are imaging field of view, spatial resolution, small exposure time, frame rate, data bandwidth, etc.


For the detection of moving objects, it is necessary to consider the adverse effects of image motion blur, accurately calculate the small exposure time that causes motion blur, and determine the model of the image sensor. The exposure time of the image sensor should be less than the small exposure time that causes motion blur. The global shutter mode is appropriate for fast exposure. Rolling shutter exposure mode is not easy to use under high-speed conditions; in order to obtain the signal-to-noise ratio, the gain of the image sensor should be as high as possible 1. The improvement of image brightness should be compensated by the energy (power) of the light source as much as possible, or the aperture stop of the lens should be increased without affecting the available imaging depth.


In system integration, the support method, precision transmission and positioning device of the DUT must also be carefully designed. This involves precision mechanical design technology, which is important for the automation of precision manufacturing and assembly industries such as flat panel displays, silicon wafers, semiconductors, and MEMS. The optical inspection system is very important. In these fields, the manufacturing process is usually carried out in an ultra-clean room, requiring the automatic optical inspection system to have a high self-cleaning ability. The material selection of the system components, the selection of pneumatic and automatic devices, the design of the motion guide and the selection of the components are all required. There are strict requirements and cannot bring secondary pollution to the production environment, especially the tested workpiece itself.


Especially the AOI system used for surface defect detection cannot bring defects (such as dust, scratches, static electricity, etc.) to the surface of the tested part during the inspection process. Therefore, for online inspection of large parts (such as high-generation liquid crystal glass substrates, silicon wafers, etc.), it is often necessary to adopt air floating support, positioning and transmission mechanisms, moving parts (such as bearings, etc.) to use self-lubricating devices, and to use FFU fans The filter unit purifies the environment of the detection system, and adopts an antistatic device to treat the workpiece with anti-static treatment.



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