Radiant energy – Photocells; circuits and apparatus – Housings
Reexamination Certificate
2000-01-07
2002-04-30
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Housings
C250S208100
Reexamination Certificate
active
06380537
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a holding head for holding an object such as an electric component (e.g., an electronic component) and particularly to such a holding head which includes a suction nozzle for applying a negative pressure to a back surface of an object and thereby holding the object and a back-surface lighting device for lighting the back surface of the object held by the suction nozzle.
2. Related Art Statement
The above-indicated holding head is employed by, e.g., an electric-component mounting device which mounts an electric component on a printed circuit board (“PCB”). In the electric-component mounting device, the holding head 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 head are deviated from respective reference positions, the component can be accurately mounted at the predetermined position on the PCB, by moving the holding head 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 head and the corresponding reference positions, and to measure them, it is widely practiced that an image taking device takes a silhouette image of the component. To take a silhouette image of the component held by the holding head, it is needed to light the back surface of the component that is held by the holding head. To this end, 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 device. 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 head which is for holding electric components, objects to be held by the holding head are not limited to the electric components. The above-explained problems may commonly occur to all objects that can be held by suction nozzles and 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 head and a transferring apparatus that has one or more of the technical features that are described below in respective paragraphs given parenthesized sequential numbers (1) to (9). 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 head comprising a support portion; a suction nozzle which applies a negative pressure to a back surface of an object and thereby holds the object, the suction nozzle being detachably attached to the support portion; and a back-surface lighting device which lights the back surface of the object held by the suction nozzle and which includes a main portion which is separate from the suction nozzle and is supported by the support portion such that when the suction nozzle is detached from the support portion, the main portion remains supported by the support portion. In the present holding head, the suction nozzle can be detached from the support portion, while the main portion of the back-surface lighting device remains supported by the support portion. For example, in the case where the free end surface of a suction pipe of the suction nozzle is so worn as to be not usable or the suction pipe is so bent as to be not usable, the suction nozzle including the suction pipe can be removed from the support portion and be replaced with a new suction nozzle, while the main portion of the back-surface lighting device still remains on the support portion for further use with the new suction nozzle. This feature contributes to decreasing the running cost of the holding head. In the case where a plurality of sorts of suction nozzles are exchanged with one another corresponding to a plurality of sorts of objects to be held, the main portion of the single back-surface lighting device may be commonly used with each selected one of the different sorts of suction nozzles. This feature also contributes to decreasing the running cost of the holding head. Moreover, even in the case where the main portion of the back-surface lighting device includes a light emitting source, the main portion need not be detached from the support portion when the different sorts of suction nozzles are exchanged with one another. This feature solves the problems that the contact of an electric-power supply circuit is worn or damaged and an electric noise is produced from the contact. According to the present invention, a portion of the back-surface lighting device may be provided as an integral portion of the suction nozzle or each of the different sorts of suction nozzles. In this case, the suction nozzle, or each suction nozzle, including the portion of back-surface lighting device is attached to, and detached from, the support portion of the holding head. Alternatively, the entirety of the back-surface lighting device may be directly supported by the support portion of the holding head. In the last case, when the suction nozzle is detached from the support portion, no portion of the
Iwaki Noriaki
Katsumi Hiroshi
Kodama Jiro
Suhara Shinsuke
Fuji Machine Mfg. Co., LTD
Le Que T.
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