Television – Special applications – Manufacturing
Reexamination Certificate
1999-01-25
2003-05-13
Lee, Young (Department: 2613)
Television
Special applications
Manufacturing
C348S095000
Reexamination Certificate
active
06563530
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a camera position-correcting method and system for compensating for displacement between the coordinate system of a component-sensing camera and that of a board-sensing camera used e.g. in an electronic component-mounting apparatus, as well as a dummy component for use in correction of camera positions.
2. Prior Art
Conventionally, in an electronic component-mounting apparatus, a board-sensing camera installed therein takes an image of a mark on a circuit board introduced into a main part of the apparatus, thereby sensing a position of the circuit board, while a component-sensing camera also installed in the apparatus takes an image of an electronic component to be mounted on the circuit board, thereby sensing a position of the electronic component. The electronic component is mounted on the circuit board after the position of the component is corrected, based on results of the sensing of the position of the circuit board and that of the component. In this case, however, unless coordinate systems of the two cameras quite agree with each other in both X and Y-directions as well as angle &thgr; (hereinafter, “&thgr;” is represented as “z”), the electronic component cannot be mounted accurately on the circuit board even if the correction of the position of the component is carried out.
For this reason, in the conventional electronic component-mounting apparatus, a displacement between the coordinate system of the component-sensing camera and that of the board-sensing camera is compensated for when the apparatus is installed, or periodically (e.g. when the apparatus is in operation) in view of changes in temperature or the like. More specifically, after a real electronic component is mounted on a dummy board introduced into the main part of the apparatus, following the steps described above, the amount of deviation between a design mounting position on the dummy board and an actual mounting position on the same is measured by the use of a measuring device additionally provided, and then a result of the measurement is inputted into the electronic component-mounting apparatus, whereby the displacement between the coordinate system of the component-sensing camera and that of the board-sensing camera is compensated for (displacements of the respective coordinate systems of the two cameras with respect to an absolute reference coordinate system of the apparatus body are also compensated for at the same time).
As described above, in the conventional electronic component-mounting apparatus, the measuring device is needed for correction of the coordinate systems of the two cameras, and at the same time, correction operations including the transfer of the dummy board and the measurement are troublesome and time-consuming. In addition, since a real electronic component is used for the correction, it is required to consider manufacturing tolerances of the electronic component, and hence the mounting and measurement described above is required to be carried out a plurality of times by using a plurality of electronic components, to thereby obtain an average value of the amounts of deviation.
SUMMARY OF THE INVENTION
It is a first object of the invention to provide a camera position-correcting method and device which makes it possible to accurately compensate for a displacement between a coordinate system peculiar to a component-sensing camera and a coordinate system peculiar to a board-sensing camera, with ease and rapidity.
It is a second object of the invention to provide a dummy component for use in accurately compensating for a displacement between a coordinate system peculiar to a component-sensing camera and a coordinate system peculiar to a board-sensing camera, with ease and rapidity.
To attain the first object, according to a first aspect of the invention, there is provided a method of correcting a camera position by compensating for a displacement between a first coordinate system peculiar to a board-sensing camera for sensing a position of a circuit board, and a second coordinate system peculiar to a component-sensing camera for sensing a position of an electronic component to be mounted on the circuit board.
This method is characterized by comprising the steps of:
causing the board-sensing camera to take an image of a dummy component in an attitude-fixed state in the first coordinate system;
causing the component-sensing camera to take an image of the dummy component in an attitude-fixed state in the second coordinate system;
calculating an amount of deviation of a center of the dummy component from a sensing center of the board-sensing camera and an amount of deviation of the center of the dummy component from a sensing center of the component-sensing camera, from a result of the taking of the image of the dummy component by the board-sensing camera and a result of the taking of the image of the dummy component by the component-sensing camera; and
correcting at least one of the first coordinate system and the second coordinate system based on the calculated amounts of deviation of the center of the dummy component.
According to this method, in the first place, by taking images of the dummy component by the board-sensing camera and the component-sensing camera in the first and second coordinate systems peculiar to the respective cameras, amounts of deviation of the sensing centers of the cameras from the center of the component sensed in the coordinate systems peculiar to the respective cameras are sensed. The taking of the images is carried out with the dummy component in the respective attitude-fixed states, and hence the two cameras each sense the dummy component in basically identical conditions. As a result, a total sum of deviations of the sensing center of the board-sensing camera and the sensing center of the component-sensing camera from the center of the dummy component form a displacement between the two cameras. Correction of the first coordinate system peculiar to the board-sensing camera and/or the second coordinate system peculiar to the component-sensing camera based on the deviations makes the two coordinate systems agree with each other. That is, the displacement between the two existing coordinate systems caused by the deviations of at least one of the coordinate systems from its or their design coordinate systems can be compensated for through the sensing of the dummy component by the respective cameras. It should be noted that although a real electronic component may be used as the dummy component, the use of a dedicated one made for this purpose is preferred from the viewpoint of accuracy.
To attain the first object, according to a second aspect of the invention, there is provided a camera position-correcting system, comprising:
a dummy component;
a board-sensing camera normally used for taking an image of a circuit board, the board-sensing camera having a first coordinate system peculiar thereto;
a component-sensing camera normally used for taking an image of an electronic component to be mounted on the circuit board, the component-sensing camera having a second coordinate system peculiar thereto;
image-taking operation control means for causing the board-sensing camera to take an image of the dummy component in an attitude-fixed state in the first coordinate system and the component-sensing camera to take an image of the dummy component in an attitude-fixed state in the second coordinate system;
deviation-calculating means for calculating an amount of deviation of a center of the dummy component form a sensing center of the board-sensing camera and an amount of deviation of the center of the dummy component from a sensing center of the component-sensing camera, from a result of the taking of the image of the dummy component by the board-sensing camera and a result of the taking of the image of the dummy component by the component-sensing camera; and
correction means for correcting at least one of the first coordinate system and the second coordinate system based on the calculate
Mohara Masayuki
Oyama Kazuyoshi
LandOfFree
Camera position-correcting method and system and dummy... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Camera position-correcting method and system and dummy..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Camera position-correcting method and system and dummy... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3031317