Metal working – Method of mechanical manufacture – With testing or indicating
Reexamination Certificate
1999-09-01
2001-03-27
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
With testing or indicating
C029S701000, C029S720000, C029S834000, C700S059000, C700S194000, C700S259000, C348S087000
Reexamination Certificate
active
06205636
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an automatic assembly apparatus which places a component to the right location based on results of a recognition operation made by an image recognition unit. The invention relates also to a method of automatic assembly.
BACKGROUND OF THE INVENTION
In the assembly of electronic components and other such parts on a substrate, where high accuracy in the location alignment is required, an image recognition method has often been employed for detecting the location. Many of the automatic assembly apparatus for electronic components have a built-in image recognition unit for aligning components to a correct location for assembly based on the results of recognition made by the image recognition unit. The image recognition unit comprises an optical system for obtaining an image of the recognition object. Information on location of a recognition object expressed in terms of an optical coordinates system detected by the optical system needs to be converted into information of a mechanical coordinates system maintaining a strict correspondence with the optical information. For conducting a conversion process, offset data representing a relative relationship in the location between the two coordinate systems and a pixel rate, which is a dimensional conversion coefficient between the pixel counts in term of optical coordinates and the actual dimensions in term of mechanical coordinates, are set and registered at the initial stage. In an image recognition unit having a fixed optical system, the initial registration is made at the time when an image recognition unit is incorporated in an automatic assembly apparatus, and does not require any modification in the contents of registration thereafter, unless the optical system is replaced.
In some automatic assembly apparatuses that handle objects different dimensions, for example a die bonder, an image recognition unit often employs a zoom lens system. An appropriate magnification index is determined for the zoom lens system in accordance with the size of a recognition object. In the conventional automatic assembly apparatus, the magnification index is decided by an operator; who determines it watching an object on a monitor screen based on his, or her, intuition and past experience. When the zoom magnification index is changed, the consequence of which is identical to the change of an optical system, the registration of the offset data and the pixel rate and other relevant data has to be renewed at each time. Setting and registration of the magnification index, offset data, and pixel rate, etc., require quite an expertise and work hours. Namely, it has been quite a burden for a line operator, and an improvement in that respect has been looked for.
The present invention addresses the above described problems, and intends to offer an automatic assembly apparatus and the method with which the burden of line operators is alleviated and the quality of operation is improved.
SUMMARY OF THE INVENTION
An automatic assembly apparatus in accordance with the present invention comprises a memory section for storing and maintaining a linkage to respective magnification indices of a zoom lens of zoom optical system, a plurality of recognition offset data that specify a relationship in the relative location between the optical coordinates system of an image recognition unit and the mechanical coordinates system of an automatic assembly apparatus incorporating the image recognition unit, a selection section for selecting in accordance with the zoom magnification index one datum among the plurality of recognition offset data stored in the memory section, a recognition process section for recognizing the image of an object of recognition pictured through a camera and outputting the results of recognition in the form of at least a location information in terms of an optical coordinates system, a coordinates conversion section for converting the location information into a location information in terms of mechanical coordinates system using a recognition offset datum selected, and a control section for controlling an automatic assembly apparatus in accordance with the converted location information.
A method of automatic assembly in accordance with the present invention comprises storing and maintaining a linkage to respective magnification indices of a zoom lens of zoom optical system, a plurality of recognition offset data that specify a relative location between the optical coordinates system of an image recognition unit and the mechanical coordinates system of an automatic assembly apparatus incorporating the image recognition unit, selecting in accordance with the zoom magnification index one datum among the plurality of recognition offset data stored in the memory section, recognizing the image of an object of recognition pictured through a camera in a recognition process section and outputting the results of recognition in the form of at least a location information in terms of optical coordinates system, converting the location information into a location information in terms of mechanical coordinates system using a recognition offset datum selected, and controlling an automatic assembly apparatus in accordance with the converted location information.
In an automatic assembly apparatus in accordance with the present invention, the recognition offset data that specify a relationship in the relative location between the optical coordinates system of an image recognition unit and the mechanical coordinates system of an automatic assembly apparatus incorporating the image recognition unit have been stored in a memory maintaining a linkage to the magnification index of a zoom optical system. Location information obtained through a camera is converted into information in terms of a mechanical coordinates system based on a recognition offset datum selected in accordance with a magnification index at which the camera pictured the image. As a result, when a zoom magnification index is changed to another magnification index that fits the size of a recognition object, the data registration operations accompanied by the change are conducted automatically to an improved operational efficiency. This also eliminates the dispersion by individual operators, which dispersion was inevitable when registration of such data was renewed by the hand of operators at their own discretion. Thus, the results of an image recognition are provided in a stable and reliable manner.
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Abe Toshiki
Ariyoshi Hiroshi
Eguchi Norifumi
Compton Eric
Hughes S. Thomas
Matsushita Electric - Industrial Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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