JPS58181532A - Vacuum chucking device - Google Patents

Abstract

PURPOSE:To make a work possible to be sucked and grasped without any deformation on the work with the same surface smoothness kept up, through which a highly accurate quality is secured, by installing more than two annular rings disposed at a suction part and an attraction mechanism capable of attracting a closed space part made up of a sucked member by means of vacuum attractiveness. CONSTITUTION:A chuck body 10 consists of each of first and second members 10a and 10b, and a first small diameter annular ring 11 and a second large diameter annular ring 12 in accord with curvature of the backside of a work W to be ground are disposed on the member 10a at a narrow interval. In order to make a vacuum chamber 13 attractable in a way of vacuum, two attractive holes 14 are formed up between rings 11 and 12. These attractive holes 14 are interconnected to an attractive chamber 15 and further interconnected to an attractive hole 16 piercing through the member 10b. The vacuum chamber 13 is attracted by vacuum via those of attractive hole 16, attractive chamber 15 and attractive hole 14 whereby the work W is sucked to the body 10 while an air chamber 18 at the central part is led to the open air through an air hole 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum chuck device that can hold a workpiece without deforming it during processing or measurement of, for example, an optical lens.

Conventionally, in this type of vacuum chuck device, as shown in FIG. 1, a ring-shaped workpiece holder has a surface L on the periphery, and an outer guide ring 4 is attached around a chuck body 3 having a cavity 2 inside. The air in the cavity 2 of the main body 3 is drawn out through the suction hole 5. For example, after placing the workpiece W to be polished on the workpiece support surface 1 and the outer guide ring 4, the cavity 2 is evacuated and the workpiece W is fixed. Since there is no support of any kind, if you draw it to an extreme, the work W
will cause deformation. Work W in this condition
Even if the workpiece W is machined to have the correct radius of curvature, when the workpiece W is released, the workpiece W returns to its original shape, which is different from the radius of curvature or surface shape at the time of processing.

On the other hand, as a method of holding the workpiece, it is often done to use adhesive to stick the workpiece to a plate or a plate, but even in this case, the workpiece is distorted by pasting, so if the workpiece is peeled off after processing, the processed surface will be damaged. There is a high possibility that curls may occur or different radii of curvature may occur. Therefore, when a workpiece is required to have a highly accurate finished state, the conventional vacuum chuck or pasting methods both have many problems and have the disadvantage that it is extremely difficult to guarantee accuracy.

An object of the present invention is to eliminate the drawbacks of the conventional examples described above and to provide a vacuum chuck device that can suction and fix a workpiece without giving it strain or deformation. A holding device characterized by having two or more annular rings arranged in the suction part of the chuck body, and provided with a suction mechanism that evacuates the sealed space formed by these annular rings and the attracted member. That is.

The present invention will be explained in detail based on the embodiment shown in FIG. 3 and below.

FIG. 3 is a plan view of an embodiment of the vacuum chuck device according to the present invention, and FIG. 4 is a sectional view showing a state in which a workpiece W is attached. The chuck body 10 has two members 1, a first and a second member.
0a and 10b, and the first member 10a has a first small-diameter annular ring 11 and a second large-diameter annular ring 1 that match the curvature of the back surface of the workpiece W to be polished, approximately in the middle of the first member 10a.
2 are arranged concentrically at narrow intervals. When the workpiece W is placed, the first and second annular rings 11.
For example, two suction holes 14 are bored between the first and second annular rings 11 and 12 so that a vacuum chamber 13 surrounded by the ring 12 and the workpiece W can be evacuated. This suction hole 14 is connected to a suction chamber 15 provided on the bottom surface of the first member 10a and surrounded by the second member 10b, and further this suction chamber 15 is penetrated by the second member 10b. It communicates with the suction hole 16. In addition, the first member 10a
In the center part is 1. An air hole 17 communicating with the outside is bored, and an air chamber 18 surrounded by the first annular ring 11, the first member 10a, and the work W has the same pressure as the outside air. Note that 19 is an outer guide ring that is constructed around the chuck body 10, connects the first and second members 10a and 10b of the body 10, and presses the periphery of the workpiece W.

Since this embodiment has the above-described configuration, the vacuum chamber 13 surrounded by the first and second annular rings 11 and 12 has the suction hole 16.
A vacuum is drawn through the suction chamber 15 and the suction hole 14, and the workpiece W is attracted to the chuck body 10. However, the central air chamber 18 communicates with the outside air through the air hole 17, and the outer space of the second annular ring 12 is also at atmospheric pressure.
The workpiece W is attracted only by the suction force acting on the vacuum chamber 13 above. Therefore, the work W will not be distorted or deformed due to the pull of the center of the work W as in the conventional example, and the radius of curvature or surface shape of the work W will hardly change between the suction state and the open state. do not have.

In addition, in the above embodiment, the first and second annular rings 11.1
The contact surface with the work W of No. 2 may have an edge shape instead of having the same radius of curvature as the back surface of the work W. Further, there is no problem even if there are two or more annular rings surrounding the vacuum chamber 13; for example, the number of annular rings may be four, and the number of vacuum chambers may be two.
/X. In the embodiment, the chuck body 10 is separated into two members 10a and 10b for convenience of processing, but it may be made into one piece or may be divided into three or more pieces. Furthermore, the outer guide link 19 may be integrated with the chuck main body lO, and there is no particular problem even if it is omitted. It goes without saying that the workpiece W can be fixed in the same manner even if it is a flat surface such as a mirror, a prism, or another aspherical surface.

As explained above, the vacuum chuck device according to the present invention has
The following effects are produced by the structure in which the part of the vacuum chamber surrounded by two or more annular rings that is in contact with the workpiece has a small area to attract the workpiece, and the other parts are kept at atmospheric pressure.

(1) It is possible to attract and hold the workpiece without deforming it.

(2) The surface accuracy of the workpiece machined in the suction state and the workpiece after release is exactly the same, ensuring high-precision quality.

(3) For example, it is possible to measure the wall thickness of a workpiece while the workpiece is being sucked, and high measurement accuracy can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional vacuum chuck, Fig. 2 is a sectional view showing the deformed state when the vacuum chuck is used for suction, and Figs. 3 and 4 are an embodiment of the vacuum chuck device according to the present invention. 3 is a plan view thereof, and FIG. 4 is a sectional view thereof. Reference numeral 10 is a chuck body, 10a, 10b are members, 11
．． 12 is a first and second annular ring; 13 is a vacuum chamber; 14
．． 16 is a suction hole, 15 is a suction chamber, 17 is an air hole, 18 is an air chamber, 19 is an outer guide ring, and W is a workpiece. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] 1. A device that holds a member to be attracted by vacuum suction, in which two or more annular rings are arranged in the adsorption part of the chuck body, and a sealed space formed by these annular rings and the member to be attracted is evacuated. A vacuum chuck device characterized in that it is equipped with a suction mechanism.