JPS6244339A - Device for precisely centering and cutting stamper - Google Patents

Abstract

PURPOSE:To enable mass production of high quality optical disk by holding the high concentricity between a stamper and the rotary axis of a cutting device and cutting sequentially precisely a bore and outer diameter without degrading the concentricity. CONSTITUTION:A stamper P having the inner and outer diameters m, n to be cut is mounted on a flat plat 11 to be covered with an outer fastening plate 12 and fastened by a screw 13. Then, a layout mark m on the central portion of thee stamper can be observed from the frond face side of a holding body 10. While the stamper holding body 10 is rotated, it is observed by a microscope installed on a device and the deflection of the layout mark m is fine adjusted by a plurality of fine adjusting screws 7 to accomplish precisely the concentricity and cut precisely the stamper set to the mark m. Next, an inner fastening plate 14 is applied to a formed inner hole M and fastened by a screw 15 to hold the stamper P, remove the outer fastening plate and similarly cut the outer diameter n. Thus, the stamper P can be precisely worked with high concentricity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides stampers that form the backbone of discs such as video discs and compact discs (digital audio discs) with inner and outer diameters with precise concentricity. This relates to a precision centering cutting VC machine for cutting.

[Conventional technology and its problems]

Optical discs such as video discs and audio discs have signal bits that record information at high density formed as a large number of fine circular grooves. When trying to manufacture such an optical disc (laser disc) by injection molding of plastic, it is necessary to
You must prepare a stamper that matches two sizes, one large and one 7yl. Stampers are usually made of hard, sticky and difficult-to-cut materials such as Ni/Kel alloys.
In order to accurately set this stamp hole in the injection molding machine and produce a high-precision optical disc, a large number of signal bit grooves and a precisely corresponding inner hole are cut in the center of the stamper. It is necessary.

The stamper is indicated by a mark of a corresponding circle that was previously marked on the stamper when recording the position of the inner hole to be cut and the position of the outer diameter. Conventionally, it was extremely difficult to set the #plate precisely in line with the center axis.

Normally, the concentricity required for compact disc stampers was acceptable as long as it had an accuracy of about 10 to 20 microns, but even this was difficult with conventional technology, and it was therefore difficult to record high-density information. Some expensive stampers were often ruined during the cutting process.

Furthermore, if possible, the concentricity of the stamper inner hole should be 1μ.
It is desirable to improve the accuracy to the order of 100 mm, but with conventional technology, such centering is almost impossible, and even if it were possible, it would be difficult to maintain the accuracy of the stamper, which is a difficult-to-cut material. It was completely impossible to cut a precise concentric inner hole and also cut the outer diameter of the stamper accordingly.

[Purpose of the invention]

The present invention has been made in order to solve the problems of the prior art as described above. To provide a device that can hold the hole firmly with precise concentricity with the axis line, first accurately cut the inner hole without disturbing the centrality during this process, and then cut the outer diameter with precise concentricity with purpose.

[Summary of the invention]

The precision centering cutting device of the present invention is a stamper whose inner diameter and outer diameter are to be cut (hereinafter referred to as a stamper to be cut).
is set with high precision concentricity on the rotation center thin line of the cutting device, firstly, the outer periphery is strongly held so that the inner diameter of the inner hole can be cut with precision concentricity, and then the circumference of the inner hole is set with high precision concentricity. The first feature is that it has a stamper holder that holds it firmly and allows it to cut the outer diameter. When this stamper holder is gripped by a chuck at the tip of a hollow spindle shaft that can rotate on the rotation center axis with an accuracy of approximately 1μ, the concentricity is further finely adjusted to the order of 1μ. W machine gun with magnification (for example, about 200 to 400 times) (
A measuring section consisting of a stereoscopic microscope) is provided close to the tip of the spindle shaft, and this measuring section measures the concentricity of the stamper to be cut with respect to the rotation center axis.
In addition, the approach of the cutting edge of the cutting tool to the marking mark on the workpiece stamper set to precise concentricity is observed, and precise cutting is made possible with the cutting edge matching the exact position.

The measuring section is configured to be movable between the observation position and the non-observation position, and can be moved to the non-observation position when the stamper holder is attached to and removed from the hollow spindle shaft. A plurality of fine adjustment screws are provided at the tip of the spindle shaft to finely adjust the stamper holder in the radial direction in order to correct the misalignment in microns observed by the microscope. After the desired concentricity is confirmed by the measuring section, a cutter is provided that can approach the front surface of the stamper holder in order to cut the inner diameter and outer diameter of the stamper being observed by the measuring section. A tool post is provided in front of the tip of the spindle shaft.

According to the present invention, the stamper to be cut is first fastened and fixed onto the stamper holder with a certain degree of concentricity, and the stamper is
After attaching the holder to the tip of the hollow spindle shaft that rotates during cutting, fine adjustments are made with even higher precision. This makes it possible to easily and reliably cut the inner diameter with high accuracy (on the order of 1 μm) while confirming precise alignment between the key mark and the cutting edge.
Since the center part is firmly held in the holder and the outer diameter is cut in the same way, centering with the desired precision and cutting of the corresponding circle can both be achieved easily and with extremely high precision, and the cutting step can be performed in the same manner as in the conventional method. It is possible to reliably prevent the stamper from becoming useless (making it a defective product).

[Embodiments of the invention]

Embodiments of the present invention will be described with reference to the drawings. The entire stamper precision centering cutting device according to the present invention is
As shown in the figure.

A hollow spindle shaft 3 is rotatably supported horizontally through a headstock body 2 supported on a machine housing 1. The hollow spindle shaft 3 can be rotated with precise concentricity on its central axis. Although the hollow spindle shaft 3 is only slightly visible near its front end in FIG. 1, it passes through the inside of the headstock body 2.
The drive unit 4 receives rotational input from a power source within the housing 1. 1a on the side wall of the housing is a speed change switch that changes the rotation speed of the spindle shaft 3;
Ro and R2 are switch buttons that change the rotation direction between forward and reverse.
S is a power switch. The configuration of the hollow spindle shaft 3 that rotates with high precision and its drive unit 4, as well as the chuck 5 and its operation 8+1 structure described below are related to other patents and utility models owned by the present applicant, and are therefore outside the scope of the present invention itself. Therefore, the details will be omitted.

The vicinity of the front end of the hollow spindle shaft 3 is shown in the enlarged sectional view of FIG. By operating the lever 5a (FIG. 1) left and right AB, it can slide in the axial direction as shown by arrows A and B in FIG. f52. The front end of the chuck 5 forms a gripping hole 5b (Fig. 2), and by inserting a shaft portion 11a of a stamper holder 10 (described later) into the gripping hole 5b and pulling the chuck 5 in the direction indicated by the arrow I) The part 11a is gripped tightly and can be rotated together with the hollow spindle sleeve 3. As is clear from FIG. 2, a screw holder 6 is fixed to the front end of the hollow spindle pongee 3, and the through center hole 6a is fixed to the front end of the hollow spindle pongee 3.
has a diameter that allows the shaft portion 11a to be inserted loosely.

A plurality of fine adjustment screws 7 are provided on the outer periphery of the screw holder 6, the tips of which are exposed into the through-center hole 6a. Preferably, fine 3
! 11 It is preferable to provide three or more setting screws 7, for example, four or six set screws 7 at equal intervals. In FIG. 1, three fine adjustment screws 7 are shown.

A stamper holder 10 according to the present invention is attached to the front end chimney 5 and screw holder 6 of such a hollow spindle pongee 3, as shown in FIG. 1, FIG. 2, or FIG. 3.

The state in which the stamper holder 10 is attached is as shown in Fig. 2 or 3, and the disassembled parts are shown in Fig. 4 (7).
5 (outer tightening plate) and FIG. 6 (inner tightening plate). Figure 7 shows the stamper on the workpiece.
FIG.

The first component constituting the stamper holder 10 is a flat plate 11. A shaft portion 11a is located at the center of the back surface of the flat plate 11.
is installed protrudingly. The diameter of the shaft portion 11a is made smaller than the inner diameter of the through center hole 6a of the screw holder 6, as described above. The front surface of the flat plate 11 is disc-shaped, and a stepped portion 111 is formed on the periphery.
] is formed. A tapped hole 11c is formed in the center of the front surface of the flat plate 11, and is used for fixing an inner tightening plate 14, which will be described later. An outer annular groove lid and an inner annular groove llc are formed on the front surface of the flat plate 11 in accordance with the outer diameter and inner diameter of the stamper to be cut.

The second component of the stamper holder 10 is the outer clamping plate 12. As shown in FIG. 2, an annular protrusion 12a is formed on the outer peripheral edge of the rear surface, and a stepped portion 11b on the outer peripheral edge of the runt plate 11.
engage with. The main part of the outer clamping plate 12 is constituted by a plurality of presser tongue pieces 12b extending radially inward from the annular main part. In the example shown in FIG. 5, the depletion tongues 12b are formed as four tapered tongues. There is a space between the tongue pieces 12b. A screw hole 12c is drilled near the outer periphery of the outer clamping plate 12, and a screw 13 is inserted into the corresponding screw hole (shown by a broken line in FIG. 4) near the outer periphery of the flat plate 11 and this screw hole 12c as shown in FIG. PttJ2. The outer fastening plate 12 and the flat plate 11 can be fixed by screwing them together. At this time, the stamper P to be cut is held between the flat plate 11 and the outer clamping plate 12 with its central region open and held under pressure mainly near the outer periphery (FIG. 2).

The stamper P to be cut is as shown in the plan view in Fig. 7, and the inner diameter to be cut is marked in the center area.
Similarly, the outer diameter is indicated with a marking mark of 0.

The next component of the stamper holder 10 is the inner clamping plate 14. As shown in Fig. 6, the planar shape of the inner clamping plate 14 has four presser tabs 14a extending radially outward from the center, and a screw hole 14b in the thick center (see Fig. m3). is bored, and the fastening screw 15 is screwed into this threaded hole 141] and the threaded hole 11c at the center of the flat plate 11, and the inner fastening plate 14 is fastened to the flat plate 11 as shown in FIG. be done. As can be seen from FIG. 5 and FIG.
It has a size that fits within the space formed between 2t+ so as not to interfere with the tongue piece 12b, and a shape that can contact the stamper P with as wide an area as possible and press the stamper.

Next to the stamper holder 10, another important feature of the present invention is the measuring section 16 shown in FIG. Measuring part 1
6 is a distal end portion 1 of an arm 18 that is supported on the upper part of the headstock body 2 and is attached to the body 17 so as to be able to pivot vertically.
9, a microscope consisting of a lens barrel 20, an objective lens 21, and an eyepiece 22 is attached. A stereoscopic microscope can also be used instead of the illustrated microscope. To adjust the focus of the microscope, the mounting body 17 can be slid back and forth by turning a screw 17a. A rack may be used instead of screws. Since the lens barrel 20 is configured to be able to swing in a vertical plane parallel to the front surface of the stamper holder 10 about a pivot 23 extending from the arm 18, the objective lens 21
is movable to both positions on the stamper holder 10 to observe the inner diameter m and outer diameter n (FIG. 7) of the stamper P. 2
4 and 25 (FIG. 1) are fixing screws, respectively. In Figure 1, the microscopes (20, 21, 22) are at the observation position, and at this position, the microscope observes whether the inner diameter m and outer diameter n of the stamper to be cut are precisely aligned with the spindle rotation center axis. If it is possible to make centering adjustment possible, and to continuously observe whether the blade (28) described below is accurately aligned with the designated cutting position before the start of cutting and during the progress of cutting, Close. Also, the microscope is
When the stamper holder 10 is attached to and detached from the spindle pongee 3, a part of the arm 18 is flipped up to a non-observation position as shown by the yI line in Fig. fjrJ1.

Finally, a guide surface 2 supported on the upper surface of the machine housing 1
6 is provided with a tool rest 27 that is movable parallel to the axis of the hollow spindle pongee 3 and in the transverse direction.
Byte) 28 is fixed. To move the cutter 28 in the axial direction, the tool rest 27 is moved forward and backward relative to the spindle sleeve 3 by means of the lever 27a and the screw handle 27b. The tool rest 27 is also moved transversely to the spindle sleeve 3 by a lever 27c or a screw handle 27d, and these movements cause the cutting edge of the tool 28 to precisely match the marking marks 1n and n of the stamper P on the workpiece. can be positioned. Note that the configuration of the tool rest 27 itself is outside the scope of the present invention, so details will be omitted.

Next, the operation of the apparatus of the present invention having the above configuration will be explained. First, the flat plate 11 is supported so that its front surface is as horizontal as possible, and a stamper P to be cut with an inner diameter m and an outer diameter n is attached thereon. Although the center part (m) of the stamper P has not yet been hollowed out, place it so that the center ○ coincides with the center of the flat plate as much as possible using the outer annular groove lid or other appropriate landmark on the flat plate 11. Cover the outer tightening plate 12 from above and tighten the screws 13 to 7.
It is fastened to the lasotho board 11. Before tightening the screw 13, visually measure the distance between the inner end of the presser tongue piece 12b and the marking mark W,
It is best to slightly adjust the stamper P so that the center 0 is aligned with the center of the stamp plate 72 as much as possible. In this way, the stamper
A stamper holding plate 10 consisting of an outer clamping plate 12 and a flat plate 11 to which P is clamped and fixed is attached to the tip of the spindle shaft as shown in FIG. Shaft portion 11 of holding body 10
Although the rear end of a is firmly gripped by the chuck 5, there is a gap between it and the through center hole 6a of the screw holder 6, so there is room for fine adjustment. Since the stamper P is only clamped by the outer clamping plate 12 and the inner clamping plate 14 is not attached yet, the marking mark 1o at the center of the stamper can be observed from the front side of the holder 10.

Here, the microscope of the measuring section 16 is lowered to the position shown in FIG. 1, the objective lens 21 is adjusted to a position where the marking mark 1n is observed, and the focus is adjusted.

@Microscope is, for example, 100 times or more, preferably 200 to 40 times
It is preferable to use a high magnification of 0 times, and it is preferable that the eyepiece lens 22 has a scale of about 0.1 to 0.5 m+n. While the stamper holder 10 is rotated by the hollow spindle 3, the deviation of the key mark m is observed.

The plurality of fine adjustment screws 7 are alternately finely adjusted depending on the degree of wobbling so that the locus of the marking mark Ifi passes through the same point on the eyepiece 22.

As a result of fine adjustment, a high precision concentricity of 1 μm or less can be obtained. The position of the objective lens 21 at this time is
When projected onto the stamper to be cut in the figure, the position will be as shown by the chain line 21.

Next, the tool post 27 is moved to align the cutting edge of the knife 28 with the marking mark m, and the stamper inner diameter is cut by rotating the spindle sleeve 3-holder 10. During actual operation, while looking through the microscope,
Slowly rotate the blade 28 to bring it slightly closer to the workpiece stamper P, and at the same time slightly move the other screw handle 27d so that the cutting edge hits a little inside the 7' mark (spindle axis) and perform trial cutting. 3 is rotating).

The approximate position of the cutter 28 at this time is projected by a chain line 28 in FIG. Then, while looking through the microscope, move the handle 27d slightly to mark the cutting edge.
, and then carefully and precisely align the cutting edge with the marking mark m to perform the main cutting. In this way, the microscope is always
Since the cutting is carried out while observing the accuracy, the formed inner hole M (shown in the center area of the stamper P in FIG. 3) can achieve highly accurate concentricity.

Next, the inner clamping plate 14 is applied to the formed inner hole M and fastened to the flat plate 11 with screws 15 (FIG. 3).

The presser tongue piece 14a of the inner clamp @ 14 presses down the stamper P from the center to the outer periphery of the stamper P in place of the outer clamp plate 12, so now remove the outer clamp plate 12 and remove the stamper P from the outside. Cut the diameter n. At this time, first place the cutting edge of the knife 28 slightly outside the outer diameter n (dashed line 28' in Fig. 7).
position), gradually mark the cutting edge while looking through the microscope m < chain line 21')! getting closer to 1. In this way, a stamper is completed, which has an inner hole M and an outer diameter that achieve the desired highly accurate concentricity.

The present invention further includes a temporary centering device that facilitates the initial mounting of the workpiece stamper on the flat plate.

This temporary centering device is as shown in No. 8. The upper surface constitutes a plane on which the flat plate 11 is placed, and an id hole 31 is formed near one end of the id block 3o to rotatably receive the seven runt plate shaft portion 11a, and a microscope is mounted near the other end. A hole 32 is formed in the hole 32 . Mounting is through hole 32
An arm 34 is supported by a mounting shaft 33 rotatably inserted into the arm 34, and a microscope 35 is attached to the tip of the arm 34. 35
A is an objective lens, and 35b is an eyepiece lens closer to the mouth.

This Wt micromachine gun with a magnification of about 50 to 100 times is sufficient.

To use this device, place the flat plate 11 on the upper surface, insert its shaft portion 11a into the id hole 31 as shown in the figure, place the stamper P′I: on the upper surface of the flat plate 11, While closing the outer clamping plate 12, the flat plate 11 is slowly rotated and the marking mark m on the stamper P is observed with a microscope. Adjust the stamper slightly with your fingertips so that the rotating part does not move around in the key mark m, and then tighten the screw 13. The stamper P, whose concentricity with the 7-rat plate 11 has been set in this way, is subjected to more precise centering adjustment at the tip of the spindle shaft shown in FIG. 12, as described above, and then subjected to cutting. If a temporary centering device as shown in FIG. 8 is used, the fine adjustment 1 after attachment to the spindle shaft will be extremely small, and the work can be done quickly and accurately.

This provisional centering device may be mounted on the mechanical housing 1 shown in FIG.

Note that the device shown in Figure tjS1 is a horizontal type, that is, a type in which the axis of rotation is arranged horizontally, but the present invention is a vertical type,
In other words, it can also be applied to a type in which the axis of rotation is vertically arranged.

In that case, the cutting tool can be placed above the rotating part, but it is preferable to place the cutting tool below the rotating part in order to protect the stamper from chips.

〔Effect of the invention〕

As explained above, according to the present invention, an inner hole having a precision concentricity of 1 μm can be easily and reliably formed in a stamper, which is a difficult-to-cut material, and the outer diameter can also be cut with the same precision. Based on this, high-quality optical (laser) discs can be mass-produced. In particular, according to the present invention, the stamper can be cut while carefully and carefully achieving the desired concentricity and checking it before starting the cutting operation, which eliminates the need for expensive work. The cutting stamper is not ruined during the cutting process, and the problems encountered in conventional stamper production can be completely resolved. Furthermore, according to the present invention, it is possible to precisely inspect whether or not the cutting was performed with the desired concentricity immediately after cutting the inner and outer diameters, and to check the highly accurate concentricity of the completed stamper. can be guaranteed.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the stamper precision centering cutting device according to the present invention, and Fig. 2 shows a stamper holder according to the present invention with an outer clamping plate and a 7
An enlarged cross-sectional view showing the stamper to be cut is tightened and fixed by the rat F plate and attached to the tip of the hollow spindle shaft. Figure 3 shows the stamper in which the stamper to be cut is tightened and fixed by the inner tightening plate and the flat plate. Figure 4 is a side view of the flat plate of the stamper holder, Figure 5 is a plan view of the outer clamping plate of the stamper holder, and Figure 6 is the inside of the stamper holder. The top view of the tightening plate, @Figure 7 is the top view of the stamper to be cut, ! @Figure 8 is a partially sectional side view of a temporary centering device used in combination with the device of FIG. 1. [Main symbols] 3...Hollow spindle shaft, 5...Chuck, 5b.
... Gripping hole, 6... Screw holder, 6a... Penetrating center hole, 7... Fine adjustment screw, 10... Stamper holder, 11... Platform plate, lla... Shaft part , 12・
...Outer tightening plate, 12b...Presser tongue piece, 13...Screw, 14...Inner tightening plate, 14a...Presser tongue piece, 15.
...screw, 16...measuring section, 21...objective lens,
22... Eyepiece, 27... Turret, 28...
Cutting tool, 30... Id block, 31... Id hole, 35... Microscope, P... Work stamper 1M...
・Inner hole.

Claims (1)

[Claims] 1. (a) A chuck having a gripping hole is inserted into the inside of a rotatable hollow spindle shaft, and a plurality of chucks having a gripping hole are provided at the tip of the spindle shaft, the tip of which can protrude from the outer periphery to the center through hole. (b) a flat plate having a shaft portion with a smaller diameter than the center through hole and gripped by the gripping hole; and a flat plate removably fastened to the flat plate. An outer clamping plate clamps and fixes a stamper to be cut placed on the plate surface with a plurality of presser tabs extending radially inward leaving the center area of the stamper, and a stamper with an inner hole of desired concentricity formed therein. a stamper holder comprising an inner clamping plate that is tightened and fixed to the flat plate in the central region, and is combinable with the chuck and screw holder; (c) the stamper holder is fixed to the stamper holder combined with the chuck and screw holder; A measuring part capable of measuring the concentricity of the inner diameter and outer diameter to be cut on the stamper to be cut in microns is provided so as to be movable between an observation position and a non-observation position; (d) while being observed by the measuring part; A precision centering cutting device for a stamper, comprising a tool rest supporting a cutter so as to be movable to a position for cutting the inner diameter and outer diameter of a stamper to be cut on a certain stamper holder. 2. (a) A chuck having a gripping hole is inserted into the interior of a rotatable hollow spindle shaft, and a plurality of fine adjustment screws are provided at the tip of the spindle shaft to allow the tip to protrude from the outer periphery to the center through hole. (b) a flat plate having a shaft portion with a smaller diameter than the central through hole and a diameter that can be gripped by the gripping hole; and a flat plate that is removably fastened to the flat plate and placed on the surface of the flat plate. An outer clamping plate that tightens and fixes the stamper to be cut with a plurality of presser tongues extending radially inward leaving the center area of the stamper, and a stamper with an inner hole of desired concentricity formed in the flat plate in the center area. (c) before assembling the stamper holder to the chuck and screw holder, the stamper holder is provided with an inner clamping plate for tightening and fixing; The stamper has a flat part that is rotatably placed on the flat plate in a horizontal plane, and is equipped with a microscope for pre-measuring the concentricity of the inner hole to be cut in the stamper placed on the flat plate and performing temporary centering. (d) After the temporary centering, the concentricity of the inner diameter and outer diameter to be cut is measured in microns on the workpiece stamper fixed to the stamper holder combined with the chuck and screw holder. (e) cutting the inner diameter and outer diameter of the stamper on the stamper holder that is being observed by the measuring section; A precision centering cutting device for a stamper, which is equipped with a tool post that supports a cutter so that it can be moved to a desired position.