JPH04328342A - Light disk master disk recorder - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a gear mark when information is optically recorded in the glass master disk of CD through the use of a laser beam. CONSTITUTION:A moving mechanism consisting of a ser laser beam source 2, at optical part 3 which shapes and controls the laser beam injected from the laser beam source 2, a turntable 4 which is rotated by a brushless-motor, a static pressure air guide 5 and a linear motor 6 disposed at the bottom of the static pressure air guide 5 is provided on a surface plate 1. The moving mechanism sends a moving optical part 7 including a condenser lens toward the radial direction of the turntable 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc master recording apparatus (hereinafter also referred to as a "cutting machine") that optically records information on a recording medium such as a glass master coated with a resist or the like using a laser beam.

0002

BACKGROUND OF THE INVENTION In order to manufacture compact discs (CDs), which have become popular as music media, a master disc with pits as information signals is created in advance. The cutting machine used is used.

[0003] The optical system of a general cutting machine is
As shown in FIG. 8, the laser beam 103 emitted from the light source 101 is focused onto the master disc 107 on the turntable 106 via the reflecting mirrors 104a, 104b, 104c and the condenser lens 105. Cutting a predetermined information signal. In this case, master 1
To record signals spirally or concentrically on 07,
A feeding mechanism is required to move either the turntable 106 or the condensing lens 105 in the radial direction of the master 107 with high precision.

[0004] Conventionally, therefore, a screw feeding mechanism has been used. This screw feeding mechanism, as shown in FIG. The output shaft 110a is connected to the threaded portion 112a of the screw/nut feeding mechanism 112 via the clutch 111a to constitute a steady feeding mechanism. Also, a timing belt 11 is provided between the pulley of the clutch 111a and the pulley of the other clutch 111b.
3 is tensioned, and a motor 114 is connected to the clutch 111b to constitute a fast-forwarding mechanism.

Furthermore, surface wobbling occurs in the master 107 rotated by the turntable 106 during cutting, and the distance H to the condenser lens 105 changes. A focusing mechanism is required to displace the beam 103 in the optical axis direction of the beam 103 to always focus the beam 103 on the master 107, and there are many variations in the thickness of the master 107, so it is necessary to absorb this.

[0006] Conventionally, therefore, a lens up-and-down mechanism to cope with the thickness of the master, a lens focusing mechanism to cope with surface wobbling, and a focusing optical system to control these are provided. The former generally includes a combination of a 1-axis linear guide mechanism (for example, a roller guide mechanism or dovetail mechanism) with a motor and a screw feed mechanism, a coil in the movable part of the lens supported by a spring, and a coil in the fixed part. A so-called moving coil drive mechanism consisting of a magnet and a yoke is used. The latter generally includes a light source section such as a helium neon (HeNe) laser and a focus detection optical system (eg, skew method method or astigmatism method).

For example, as shown in FIG. 10, in a conventional focusing mechanism and optical system, a laser beam emitted from a laser light source 115 is transmitted through a mirror (not shown), etc.
05, is reflected by the glass master disk 107, passes through the condenser lens 105 again, enters the focus detection optical system 116, and detects a focal shift. In addition, the lens barrel 117 of the condenser lens 105
This lens barrel 117 is movably supported by a spring 125.
A coil 118 is provided on the upper part of the lens, and a magnet 119 and a yoke 120 sandwiching the coil 118 constitute a so-called voice coil lens drive mechanism 121, and a current is applied to correct the focus error signal of the focus detection optical system 116. This absorbs the surface runout of the master 107. Furthermore, the lens drive mechanism 121 is entirely connected to the condenser lens 10.
In order to move the master 107 several mm in the direction of the optical axis of the master 107, a uniaxial movement mechanism 124 using a screw/nut mechanism 123 is provided between the fixed part 122 and the lens drive mechanism 121.
This corrects for variations in thickness.

[0008]

[Problems to be Solved by the Invention] However, in the conventional optical disk master recording device as described above, the turntable is fed by a screw/nut feeding mechanism, so the higher the feeding accuracy is, the more the feed screw becomes The characteristic thread precision of each pitch appears in the cutting, and this is the cause of the so-called gear marks that appear on the final molded disc. In addition, if a method is adopted in which a lens drive mechanism is installed in this feeding mechanism,
The moving load had to be made as light as possible and as rigid as possible.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention uses a feeding mechanism incorporating a static air guide and a linear motor to feed the condenser lens in the radial direction of the turntable.

0010

[Operation] Equipped with a feeding mechanism that uses static air guide and a linear motor to send the condensing lens in the radial direction of the turntable, minimizing frictional resistance when moving the lens drive mechanism by a minute distance or when starting it. It can be made smaller and does not generate gear marks like when a screw/nut feeding mechanism is used.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a plan view of an optical disk master recording device to which the present invention is applied, FIG. 2 is a front view of the device, FIG. 3 is a perspective view of the lens drive mechanism attached to the feeding mechanism of the device, and FIG. A perspective view of another attachment state of the lens drive mechanism to the feed mechanism of the same device, FIG. 5 is a plan view of the lens movable part of the same device, FIG. 6 is a half-sectional view of the lens movable part, and FIG. It is a diagram showing the amount of displacement of the part.

On the stone surface plate 1 with a high-performance compact anti-vibration table, there is a helium cadmium laser (HeCd laser) light source 2 that serves as a laser light source, and an optical section that shapes and controls the laser light emitted from the laser light source 2. 3, a turntable 4 supported by a static air bearing (not shown) and rotated by a brushless motor, a static air guide 5, and a linear motor 6 disposed at the bottom of the static air guide 5. A moving optical section 7 including a condensing lens is sent in the radial direction of the turntable 4 by means of a static air guide 5 and a linear motor 6 that constitute this moving mechanism.

[0013] As described above, by using a helium cadmium laser as a recording laser light source, the entire apparatus can be downsized. Furthermore, by using the static pressure air guide 5 and the linear motor 6 as the feeding mechanism for the moving optical section 7,
There is no so-called gear mark that occurs when a screw/nut feeding mechanism is used.

Furthermore, the focusing mechanism of the movable optical unit 7 must move along the radial direction of the turntable 4, and should protrude in a direction perpendicular to the moving direction of the guide 5a of the static air guide 5. is attached to the slider 5b. Furthermore, the moving optical section 7 includes a lens drive mechanism 8.
has been established. By providing this lens drive mechanism 8 on the side surface of the slider 5b in the moving direction as shown in FIG. is supported by the force obtained from all directions of the blown air flow (arrow),
A moment M that causes the lens drive mechanism 8 to fall forward in the movement direction is not generated due to the weight of the lens drive mechanism 8, and there is no catch when starting movement, allowing stable and highly rigid feeding.

As shown in FIGS. 5 and 6, the lens drive mechanism 8 includes a coil 1 at the top of the lens barrel 11 of the condenser lens 10.
3, and the magnet 14 and yoke 15 sandwiching this coil 13 constitute a so-called voice coil,
These entire movable parts 16 are supported by a spiral spring 12 (gimbal spring). spiral spring 12
As shown in Fig. 7, by using the lens, the movable range of the lens is widened, it is possible to absorb variations in the thickness of the master disc D placed on the turntable 4, and no other parts are required. The weight of the optical section 7 can be reduced. Furthermore, by using a semiconductor laser as the light source of the focusing optical system, both the weight and volume can be significantly reduced compared to the case where a conventional helium-neon laser is used, making it possible to further reduce the weight.

[0016]

[Effects of the Invention] As explained above, according to the present invention,
A feeding mechanism is provided to send the condensing lens in the radial direction of the turntable using a static air guide and a linear motor, so the optical section can be moved extremely smoothly, and there is no gear mark like when using a screw nut feeding mechanism. will no longer occur.

[Brief explanation of drawings]

[Fig. 1] A plan view of an optical disc master recording device to which the present invention is applied.

[Figure 2] Front view of the device

[Figure 3] A perspective view of the lens drive mechanism attached to the feed mechanism of the device

[Fig. 4] A perspective view of another state in which the lens drive mechanism is attached to the feed mechanism of the device.

[Figure 5] Plan view of the lens movable part of the device

[Figure 6] Half-sectional view of the lens movable part

[Figure 7] Diagram showing the amount of displacement of the lens movable part

[Figure 8] Configuration diagram showing the optical system of a general cutting machine

[Fig. 9] Schematic plan view of a conventional feeding mechanism

[Fig. 10] Schematic front view of a conventional lens drive mechanism

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Stone surface plate, 2... Helium cadmium laser, 3... Optical section, 4... Turntable, 5... Static pressure air guide, 6... Linear motor, 7... Moving optical section, 8... Lens drive mechanism, 1
2...Spiral spring.

Claims (3)

[Claims] Claim 1: An optical disk master recording device that forms a laser beam and then focuses it and records a signal in a spiral or concentric manner on a rotating recording master, and this recording device uses a static air guide and a linear motor. An optical disc master recording device comprising a feeding mechanism that moves a lens drive mechanism in a radial direction of a turntable. 2. The optical disk master recording device according to claim 1, further comprising a lens drive mechanism provided on a side surface of the feed mechanism in the traveling direction. 3. The optical disk master recording device according to claim 1, wherein the movable part of the lens drive mechanism including the condensing lens is supported by the main body of the lens drive mechanism by a spiral spring.