Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-05-24
2003-01-21
Huson, Gregory (Department: 3751)
Metal working
Method of mechanical manufacture
Electrical device making
C029S721000, C029S743000, C029S740000
Reexamination Certificate
active
06507997
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electric-component (EC) mounting method, an EC treating method, and an EC mounting apparatus, and particularly to the art of controlling the mounting or treating of electric components (ECs), in particular, electronic components.
2. Discussion of Related Art
It has been practiced to take, before an EC is mounted on a printed wiring board (PWB), an image of the EC sucked and held by a suction nozzle, as seen in a direction perpendicular to an axial direction of the nozzle parallel to an axis line thereof. Based on image data representing the thus taken image, it is judged whether the EC held by the nozzle is taking a lying-on-its-side posture, that is, whether the EC is taking an incorrect rotation position deviated by 90 degrees from a correct rotation position thereof about an axis line perpendicular to the axis line of the nozzle. If it is judged that the EC is taking the lying-on-its-side posture, the EC is not mounted on the PWB to prevent the production of a defective printed circuit board (PCB) on which the EC having the incorrect posture is mounted.
However, even the above-described method cannot prevent the production of all defective PCBs. For example, even in the case where a suction nozzle holds an EC such that the EC is not taking a lying-on-its-side posture, if the nozzle has a dimensional error with respect to its axial-direction dimension, then the distance between the EC and the PWB is adversely influenced by the dimensional error, so that the amount of access of the EC to the PWB may be excessive and accordingly the EC may be subjected to an excessive load and even be damaged, or that the amount of access of the EC to the PWB may be short and accordingly the EC may not be mounted at a correct EC-mount place on the PWB.
The above-explained problems mean that it is difficult to control appropriately the access of a suction nozzle to some member. Similar problems are experienced when a suction nozzle receives an EC from an EC supplying device. For example, if a suction nozzle has an error with respect to its axial-direction dimension and the distance between the nozzle and the EC is adversely influenced by the dimensional error, the amount of access of the nozzle to the EC may be excessive and accordingly the EC may be subjected to an excessive load and even be damaged, or the amount of access of the nozzle to the EC may be short and accordingly the nozzle may fail to suck or hold the EC.
SUMMARY OF THE INVENTION
The present invention provides an EC mounting method, an EC treating method, an EC mounting apparatus, and an EC treating apparatus which have the following features. Those features are described, like claims, in respective paragraphs which are given respective numbers. Any feature that includes another feature shall do so by referring to the number given to the latter feature. However, the following features and the appropriate combinations thereof are just examples to which the technical features, and the combinations thereof, described in the specification are by no means limited. In addition, in the case where one feature recites a plurality of items, it is not essentially required that all of those items be simultaneously employed in the one feature. That is, it is possible to select and employ only a portion (one, two, . . . , but not all) of those items.
(1) According to a first feature of the present invention, there is provided a method of mounting an electric component on a circuit substrate, the method comprising the steps of moving at least one of a suction nozzle and an electric-component supplying device toward the other of the suction nozzle and the electric-component supplying device, so that the nozzle applies a suction to the electric component supplied by the supplying device and thereby receives the component, moving at least one of the suction nozzle and the circuit substrate toward the other of the nozzle and the substrate, so that the nozzle mounts the electric component on the substrate, taking an image of at least a portion of the electric component sucked and held by the suction nozzle, as seen in a direction perpendicular to an axial direction of the nozzle, in a state in which the nozzle takes a known position in the axial direction, determining, based on image data representing the taken image, a position of at least a mounted surface of the electric component that is opposite to a sucked surface of the component sucked by the suction nozzle, and controlling, based on the determined position, a movement of at least one of the suction nozzle and at least one of the electric-component supplying device and the circuit substrate, toward the other of the nozzle and the at least one of the supplying device and the substrate.
The taking step may include taking an image of the electric component only, and the determining step may include determining a position of the mounted surface of the component only. Alternatively, the taking step may additionally include taking an image of an end portion of the suction nozzle that applies the suction, and the determining step may additionally include determining a position of a sucking end surface of the nozzle that applies the suction.
The direction of movement of at least one of the suction nozzle and at least one of the electric-component supplying device and the circuit substrate toward the other of the nozzle and the at least one of the supplying device and the substrate may be a vertical direction, or a direction inclined relative to the vertical direction.
The known position taken by the suction nozzle in the axial direction thereof is defined as that taken by a portion of the nozzle that is held by, e.g., a nozzle holder, a position of that portion relative to the nozzle holder in the axial direction being not changed by, e.g., a manufacturing error of the nozzle or wearing of the sucking end surface of the nozzle. Therefore, the position of the suction nozzle is equivalent to that of the nozzle holder. In the case where the suction nozzle is held by the nozzle holder such that the nozzle is not movable in the axial direction thereof relative to the holder, the position of the portion of the nozzle held by the holder does not change relative to the holder. Thus, if the position of the holder is known, then the position of the nozzle is also known. On the other hand, in the case where the nozzle is held by the holder such that the nozzle is movable in the axial direction relative to the holder, the position of the nozzle may not be known even if the position of the holder may be known. In the latter case, therefore, the position of the nozzle must be discussed in the state in which the nozzle takes a prescribed position relative to the holder, e.g., an advancement-end position relative to the holder.
The state in which the suction nozzle takes the known position in the axial direction may be, in the literal sense of the words, a state in which an absolute position taken by the nozzle in the axial direction is known, or may be a state in which a position taken by the nozzle in the axial direction when an image taking operation is performed is constant. In the present embodiment, it is at least needed to detect an error of the actual position of the mounted surface of the electric component from an ideal (i.e., target or correct) position, and it is not essentially needed to detect an absolute position of the mounted surface.
The known position taken by the suction nozzle may be a designed position or a measured position. The designed position means a position to be taken by the suction nozzle in a state in which an electric-component (EC) mounting system has been assembled and the fine adjustment of each element of the system has been completed. If an image taking operation is performed in a state in which the nozzle takes a prescribed position in the axial direction, the designed position can be used as the known position. On the other hand, if the nozzle does not take a prescribed position in the
Kawai Takayoshi
Suhara Shinsuke
Tsuchiya Yusuke
Fuji Machine Mfg. Co. Ltd.
Huson Gregory
Le Huyen
Oliff & Berridg,e PLC
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