JPH04256501A - Cutting device for minute cutting - Google Patents

Abstract

PURPOSE:To make machining of a guide groove and a preformat pit possible at the same time at a fixed track pitch by mounting both a tool for guide groove cutting and a tool for format pitch machining on a tool mounting part, and making the distance fixed between both. CONSTITUTION:Both a preformat pit machining tool 3 and a guide groove cutting tool 4 are mounted on a tool mounting part 11 at a fixed interval. Further, to cause this preformat pit machining tool 3 to perform particular displacement action, a vibrator 2 is interposed between the tool mounting part 11 and the preformat pit machining tool 3.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro-incision cutting device used for machining preformat pits and guide grooves in optical disk molds.

0002

[Prior Art/Problems to be Solved by the Invention] Optical discs require spiral guide grooves with a constant depth and preformat pits formed between these guide grooves. Previously, each required a separate process. As a cutting device that can perform these processes, the device disclosed in Japanese Patent Application Laid-open No. 1-281848 is known, but since this device cannot obtain a sufficiently high resonance frequency, it is not suitable for processing preformatted pits. This required a huge amount of processing time. Furthermore, since the guide grooves and the preformat pits are processed in separate processes, it is extremely difficult to match their positions (track pitch) in the radial direction of the optical disc.

The cutting device disclosed in the above-mentioned publication will be briefly explained below with reference to FIGS. 2 and 3. The microgrooving tool T shown in FIG. 2 has a blade part 21 and a shank 2.
A groove 23 is formed between the groove 2 and the piezoelectric element 26. The blade part 21 has a slit S
It has a parallel plate spring structure 25 configured by a combination of a square hole A and a square hole A, and is configured to be displaced in the incision direction as the piezoelectric element 26 expands and contracts. 2 in the diagram
4 is a cutting edge.

The tool T is attached to the cutting device shown in FIG. 3, and cuts a spiral microgroove into a rotating workpiece W. In the figure, numeral 38 is a displacement meter fixed to the shank 22, which measures surface run-out due to rotation of the workpiece W. Based on the detected value of the displacement meter 38, the piezoelectric element 2
The voltage applied to 6 is controlled. In the figure, 30 is an air damper for vibration isolation, 31 is a base, 32 is an air spindle for mounting and fixing the workpiece W, and 33 is its motor. 34 is an air slide that slides the air spindles 32 in parallel and simultaneously. 35 is a gate-shaped frame, 36 is a pillar part thereof, and 37 is a beam part.

The present invention has been devised in view of the above-mentioned conventional technical problems and to effectively solve them. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a micro-incision cutting device capable of simultaneously machining guide grooves and preformat pits at a constant track pitch in machining an optical disc mold.

[0006]

[Means for Solving the Problems] A cutting device for making minute cuts according to the present invention has a tool mounting portion whose movement in the cutting direction is driven by a first piezoelectric element in order to compensate for surface runout of a rotating workpiece. a cutting tool for cutting a guide groove fixed to the tool mounting part, a cutting tool for machining a preformat pit mounted to the tool mounting part at a predetermined distance from the cutting tool for cutting the guide groove, and the tool mounting part. and a vibrator that is interposed between the part and the preformat pit machining tool and vibrates in response to a preformat pit signal.

[0007] Furthermore, in the micro-incision cutting device according to the present invention, the distance between the guide groove cutting tool and the preformat pit processing tool is changed between the tool mounting portion and the vibrator. Adjustment means may also be provided.

[0008]

[Operation and Effects of the Invention] In the micro-cutting cutting device according to the present invention, the guide groove cutting tool and the preformat pit processing tool are both attached to the tool mounting part, so the distance between them is constant. By setting this to an integral multiple of half the track pitch of the optical disc, the guide groove and preformat pit can be processed simultaneously at a constant track pitch. Since the tool mounting portion is driven by a piezoelectric element to compensate for surface runout of the workpiece, both the guide groove and the preformat pit are simultaneously cut to a constant depth.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A micro-incision cutting device according to an embodiment of the present invention will be described below with reference to FIG. As shown in FIG. 1, in this embodiment, a tool mounting part 11 at the tip of the tool stand 1 has a preformat pit machining tool 3.
and a grooving tool 4 are attached to the workpiece 7 so as to be spaced apart from each other in the radial direction of the workpiece 7 by a distance approximately half the track pitch of the optical disk. Since the track pitch of an optical disc is 1.6 μm, half of the track pitch is 0.8 μm. The tool stand 1 is provided with a driving piezoelectric element 10 between the shank and the tool mounting part 11, and although it is omitted in FIG.
The tool attachment part 11 is given elasticity by employing a parallel spring structure, and is movable by expansion and contraction of the piezoelectric element 10.

The preformat pit machining tool 3 is attached to a guide 6 attached to the tip 11 of the tool stand 1 via a piezoelectric type vibrator 2, and this guide 6 is also connected to the tool attachment part 11. Elasticity is provided by employing a similar parallel spring structure. A positioning piezoelectric element 5 is fixed to the side surface of the guide 6 for determining the position of the preformat pit machining tool 3 with respect to the grooving tool 4. By expanding and contracting the vibrator 2, the height of the cutting tool 3 with respect to the cutting tool 4 is made equal, and the piezoelectric element 5
The distance of bite 3 from bite 4 is adjusted by expanding and contracting. The voltage applied to the vibrator 2 and the piezoelectric element 5 is controlled by the first amplifier 14 based on a control signal from the first CPU 13.
is output from.

A displacement gauge 12 for measuring the displacement of the workpiece 7 is fixed to the side surface of the tool mounting portion 11 of the tool stand 1 in order to compensate for surface runout caused by rotation of the workpiece 7. The displacement signal measured by the displacement meter 12 is input to the second CPU 8, and the CPU 8 causes the second amplifier 9 to output a voltage for compensating for surface runout to the piezoelectric element 10 in accordance with this displacement signal.
A control signal is output from the second amplifier 9 to the second amplifier 9. As a result, the tool mounting portion 11 follows the surface runout. In Figure 1, 1
5 is a displacement meter amplifier that amplifies and linearizes the displacement signal of the displacement meter 12.

A voltage based on a preformat signal from the first CPU 13 is applied to the vibrator 2 from the first amplifier 14, and the preformat machining tool 3 cuts a preformat pit. At this time, since the tool mounting portion 11 of the tool stand 1 follows the surface runout of the workpiece 7, the depth of the machined pit remains constant. Further, since the distance between the grooving tool 4 and the preformat pit machining tool 3 is also fixed, the guide grooves and preformat pits are formed at a constant track pitch.

[0013] In the above embodiment, the distance between both cutting tools was set to 0.8 μm, but if n in the following equation is an integer, (0.8 +
It is also possible to set it as 1.6n) μm.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a schematic configuration of a micro-incision cutting device according to the present invention.

FIG. 2 is a front view showing a tool used in a micro-incision cutting device in the prior art.

3 is a perspective view showing a prior art micro-incision cutting device in which the tool of FIG. 2 is used; FIG.

[Explanation of symbols]

2 Vibrator 3 Preformat pit machining tool 4 Grooving tool 5 as guide groove cutting tool Positioning piezoelectric element 6 as adjustment means Guide 7 as adjustment means Workpiece 10 Piezoelectric element 11 Tool attachment part

Claims (2)

[Claims] Claim 1: In order to compensate for the surface runout of the rotating workpiece (7), the first piezoelectric element (10) moves in the cutting direction.
a tool mounting part (11) driven by the tool mounting part (11); a guide groove cutting tool (4) fixed to the tool mounting part (11);
The tool mounting part (11) is equipped with the guide groove cutting tool (
4), a preformat pit machining tool (3) installed at a predetermined distance from the tool mounting part (11) and a preformat pit machining tool (
3) and a vibrator (2) that vibrates in response to a preformat pit signal. 2. The distance between the tool attachment part (11) and the vibrator (2), and the distance between the guide groove cutting tool (4) and the preformat pit processing tool (3) is changed. 2. The micro-incision cutting device according to claim 1, further comprising adjusting means (5, 6) for adjusting the cutting angle.