Radiant energy – Invisible radiant energy responsive electric signalling – Infrared responsive
Reexamination Certificate
2000-01-07
2002-08-20
Hannaher, Constantine (Department: 2878)
Radiant energy
Invisible radiant energy responsive electric signalling
Infrared responsive
C250S341700, C356S370000
Reexamination Certificate
active
06437333
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a holding apparatus of r holding an object such as an electric component (e.g., an electronic component), a transferring apparatus including the holding apparatus, and an image taking system and an image taking method each for taking an image of an object held by a holding device, and relates particularly to the art of lighting an object.
2. Related Art Statement
The above-indicated holding apparatus , a transferring apparatus, an image taking system, and an image taking method are employed by, e.g. , an electric-component mounting system which mounts an electric component on a printed circuit board (“PCB”). In the electric-component mounting system, the holding apparatus receives an electric component from an electric-component supplying device and mounts the component at a predetermined position on the PCB. Even if the current X-direction and Y-direction positions of the component held by the holding apparatus are deviated from respective reference positions, the component can be accurately mounted at the predetermined position on the PCB, by moving the holding apparatus to a corrected or modified position deviated from the predetermined position by respective distances between the X-direction and Y-direction positions of the component and the corresponding reference positions. To this end, it is needed to measure the respective distances between the X-direction and Y-direction positions of the component held by the holding apparatus and the corresponding reference positions. In addition, in some cases, it is needed to read characters and/or a bar code affixed to the component and judge of what sort the component is based on the read characters and/or bar code. To these ends, it is widely practiced that an image taking device takes an image of the component. Depending upon respective shapes of different sorts of electric components and/or different purposes of image taking, a silhouette image of each component is preferably needed in some cases, and a front-surface image of each component is preferably needed in other cases. To take a silhouette image of an electric component held by the holding apparatus, it is needed to light a back surface of the component that is held by the holding apparatus. To take a front-surface image of the component held by the holding apparatus, it is needed to light a front surface of the component that is opposed to the image taking device.
There is a holding apparatus which includes a suction nozzle for sucking and holding an electric component; a front-surface lighting device which lights a front surface of the component held by the nozzle; and a back-surface lighting device which lights a back surface of the component. With this holding apparatus, an image taking device can selectively take a silhouette image or a front-surface image of the component. Thus, the holding apparatus can be widely used. However, the light emitting surface of the back-surface lighting device is considerably light and, if the image taking device takes a front-surface image of the component in the background defined by the light emitting surface while the front-surface lighting device lights the front surface of the component, the image taking device takes, in addition to the front-surface image of the component, a light image of the background. In this case, it is difficult to extract accurately the image of the object from the background, and incorrect results may be obtained by the processing of the extracted image of the object. This problem might be solved by moving the back-surface lighting device away from the object when the front-surface image of the object is taken. In the latter case, however, the holding apparatus needs a more complicated structure, which leads to another problem that the production cost of the holding apparatus increases. In a particular case where the taking of front-surface image and the taking of silhouette image are frequently switched with each other, it needs a long time to switch them, which leads to lowering the operating efficiency of the holding apparatus.
In addition, it has widely been practiced that the suction nozzle and a main portion of the back-surface lighting device are constructed as an integral unit. For example, a light emitting plate including a plurality of point light sources, such as light emitting diodes, and a diffusing layer for diffusing the lights emitted by the point light sources and thereby emitting a substantially uniform light, is fixed to the suction nozzle, or alternatively a light emitting plate which absorbs infrared rays externally incident thereto and emits a visible light, a reflecting plate which reflects a light externally incident thereto, or a diffusing block which diffuses a light externally incident thereto and emits a light toward the suction nozzle, is fixed to the suction nozzle.
However, if the main portion of the back-surface lighting device is provided as the integral portion of the suction nozzle, the suction nozzle costs high. Generally, the suction nozzle includes a suction pipe, which may be bent to be not usable or whose suction surface (i.e., free end surface) may be worn to be not usable. If the main portion of the back-surface lighting device is provided as the integral portion of the suction nozzle, the suction nozzle as a whole including the main portion of the back-surface lighting device must be replaced with another suction nozzle including a main portion of another back-surface lighting device. This manner leads to increasing the running cost of the electric-component mounting system. Meanwhile, in the case where a plurality of sorts of suction nozzles are exchanged with one another corresponding to a plurality of sorts of electric components to be held, the number of suction nozzles employed increases. If each of those suction nozzles includes a main portion of a back-surface lighting device, the running cost costs very high. Moreover, in the case where the main portion of each back-surface lighting device includes a light emitting source, the light emitting source must be supplied with electric power. In the last case, when the suction nozzles are repetitively exchanged with one another, the contact of an electric-power supply circuit which supplies the electric power to the light emitting source may be worn or damaged, or an electric noise may be produced from the contact.
While the foregoing explanation relates to the holding apparatus, the transferring apparatus, the image taking device, etc. which are for use with electric components, objects to be held by the holding apparatus are not limited to the electric components. The above-explained problems may commonly occur to all holding apparatuses, all transferring apparatuses, all image taking devices, etc. that are for use with objects whose images need to be taken to recognize each object by image processing or to determine X-direction, Y-direction, and rotation positions of each object, measure one or more dimensions of each object, etc.
SUMMARY OF THE INVENTION
The present invention provides a holding apparatus, a transferring apparatus, an image taking system, and an image taking method that have one or more of the technical features that are described below in respective paragraphs given parenthesized sequential numbers (1) to (15). Any technical feature which includes another technical feature shall do so by referring, at the beginning, to the parenthesized sequential number given to that technical feature. Thus, two or more of the following technical features may be combined, if appropriate. Each technical feature may be accompanied by a supplemental explanation, as needed. However, the following technical features and the combinations thereof are just examples to which the present invention is by no means limited.
(1) According to a first feature of the present invention, there is provided a holding apparatus comprising a suction nozzle which applies a negative pressure to a back surface of an object and thereby holds t
Iwaki Noriaki
Katsumi Hiroshi
Kodama Jiro
Suhara Shinsuke
Fuji Machine Mfg. Co. Ltd.
Gagliardi Albert
Hannaher Constantine
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