JPS61133034A - Optical information device - Google Patents

Abstract

PURPOSE:To erase a signal satisfactorily with a high reliability by a small-sized device available at a low cost by pre-heating the device when the signal recorded on an optical disk is erased. CONSTITUTION:The disk 13 is heated near to a temperature T2 by a heater 18 constituted of a halogen lamp, etc., after which a recorded signal erase beam 15 is made incident. Accordingly its heat energy power is small. By making a light beam 25 incident on the disk 19, it can be heated near to the temperature T2.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention optically records, reproduces, and erases information [Background of the Invention] As described in Japanese Patent Application Laid-Open No. 54-83404, a conventional device When recording on an optical disk, there were devices that preheated the disk by irradiating it with laser light or the like, but there was no device that preheated the disk during erasing.

[Purpose of the invention]

The present invention is based on signals recorded on optical discs.

[Summary of the invention]

In order to erase the signal recorded on an optical disk, it is necessary to raise the temperature of the optical disk near the signal to a critical point, but it is not easy to raise the temperature from room temperature to the critical temperature. Therefore, before erasing, it is preheated to near the critical temperature to reduce the amount of radiation necessary to erase the signal and facilitate erasing.

[Embodiments of the invention]

There are fees etc. The above-mentioned recording material reversibly undergoes a metal-to-metal transition from a β phase to a γ phase by thermal energy, resulting in a change in light reflectance. For this purpose, a disk (hereinafter referred to as a disk) on which an intermetallic transition material is attached by irradiation with light such as a laser
It is possible to record, play back, and erase signals. In this case, generally a considerably large energy of the light source is required, and assuming a He--Ne laser, a large one is required, which poses practical difficulties. Furthermore, when using a semiconductor laser, it is difficult to focus the beam and the wavelength is longer than that of a gas laser, so this is an example of a high-density recording device. In FIG. 3, 1 is a disk, 2 is a turntable for rotating the disk 1, and the disk 1 is transferred as indicated by an arrow 3 by a transfer device (not shown). At this time, a light beam 5 is generated by a light source 4 such as a laser. light beam 5
is modulated by a light modulator 6 that controls the light intensity according to a signal input to a terminal A, and enters a lens 10 through a lens 7, a beam splitter 8, and a mirror 9. V trash 1
0 converges a light beam 5 into a minute spot and irradiates it onto the disc 1.The energy of the light beam 5 changes the light on the disc 1, and information is recorded thereon. For reproduction, as in recording, the disc 1 is rotated by the turntable 2, and the light beam 5 is passed through the optical system (lens 7, beam splitter 11-8, mirror 9, lens 1G) without modulation to record the disc 1. Focus on the pattern. The light beam reflected by disk 1 passes through the same path as the going path and passes through the beam splitter.
The light enters the photodetector 12 at 8.

At this time, the light beam 6 is modulated by the recording pattern and converted into an electrical signal by the photodetector 12.

When erasing a signal, the light beam 5 generated from the light source 4 is transmitted through the optical modulator 6, the lens 7, and the beam splinter 8, as in the case of recording.
, passes through mirror 9 and enters lens 10. lens 10
The optical beam 5 is focused on a minute spot and irradiated onto the disk 1 on which the signal has been recorded. At this time, the light source 4 is adjusted to have an intensity suitable for erasing, and the light beam 5 is modulated by inputting a signal corresponding to the erasing pattern to the input terminal of the optical modulator 6. Note that this type of apparatus requires focus control for focusing the light beam 6 on the disk 1 and tracking control for causing the light beam 6 to follow the recording pattern, but these are omitted.

FIG. 2 shows the dependence of the reflectance on the heating and cooling temperature when the intermetallic transition material after recording is heated and slowly cooled.

By heating and rapidly cooling the intermetallic transition material, the reflectance becomes high <RL
become. Next, when it is heated and slowly cooled, the reflectance changes depending on the temperature. When the heating and cooling temperature is between T2 and T3, the reflectance decreases to R2 and the recorded signal is erased.

This is because when the temperature is between T2 and T3, the metal transitions from the γ phase to the β phase and its optical properties change. Note that if the metal material is heated too much, the metal material will evaporate, the surface properties will deteriorate, and the reflectance will drop, so there is a limit to the heating temperature. ! When signal erasure is performed using the apparatus shown in FIG. 3, the irradiation time per unit area of the disk becomes shorter at 600 rP or more.

For this reason, it is necessary to increase the irradiation energy by using a high-power laser. However, as V-zar He-Ne
When a laser is used, it is very large, expensive, and has poor reliability, making it difficult to use in practice.

In addition, high-output semiconductor lasers have recently attracted attention, but it is difficult to narrow down the laser beam, making it difficult to obtain the necessary irradiation amount.

The present invention eliminates the drawbacks of the above-mentioned conventional examples. The details of the present invention will be described below with reference to drawings showing embodiments. In FIG. 1, 13 is a disk, and 14 is a turntable for rotating the disk 13, which rotates in the direction of the arrow. 15 is a recording signal erasing beam from a laser, 16 is a tracking mirror, and 17 is a lens, which irradiates the recording signal erasing beam onto the disk. Reference numeral 18 denotes a heater for heating the disk, which is composed of a halogen lamp or the like. Heater 18
The disk 13 is heated near T2 temperature in FIG. 2, and then the recording signal erasing beam 15 is irradiated thereon. Therefore, the thermal energy power of the recording signal erasing beam 15 is less than that of the conventional device.

Further, a configuration as shown in FIG. 4 is conceivable. 19 is a disk, and 20 is a tar/table for rotating the disk 19, which rotates in the direction of the arrow. 21 is a recording signal erasing beam from a laser, 22 is a tracking mirror, and 23 is a lens that irradiates the recording signal erasing beam onto the disk. 24 is a semiconductor laser, 25 is a light beam, and 26 is a condenser lens that focuses the light beam 25 on the disk 19. light beam 2
5 onto the disk 19, the disk temperature is heated to around T2 in FIG. Semiconductor lasers are suitable as rounding heating sources because they are small and can produce high output.

As another example, in the configuration shown in FIG. 3, the output of the light beam 5 from the laser 4 is set as shown in FIG. In this case, the movement of the turntable 2 is stopped and the signals are recorded concentrically on the disk. In FIG. 5, the disk is irradiated with laser power at the maximum output WL at time ttt. At this time, the rotation of the disk and the time 1. For example, irradiation is performed at laser power W1 during one rotation of the disk.

And the disc i degree is T! When the temperature is raised to around 8I, V-
The laser beam 5 is modulated by a modulator 6 and irradiated onto the disk, erasing the signal according to the erasing pattern.

〔Effect of the invention〕

As described above, the following effects can be obtained by the configuration of the present invention. That is, since the disk is heated in advance, the erasing power can be reduced, the laser can be kept small, the device can be made small and inexpensive, and the reliability can be increased. In addition, when recording signals concentrically on a disk, the heating source and signal source laser can be the same, so the device is simple, and the heating track and signal track are on the same surface, so there is no uneven heating. Can be erased.

[Brief explanation of the drawing]

FIG. 2 is a schematic diagram of the main parts, FIG. 4 is a schematic diagram of an embodiment of the pond of the present invention, and FIG. 5 is a diagram of erasing butter/signal waveforms in different embodiments of the present invention. be. 13...disc, 14...turntable, 15
. . . Recording signal erasing beam, 16. Tracking mirror, 17. Lens, 18. Heater.躬 1 fig. 3 fig. 2.

Claims (1)

[Claims] 1. Recording is performed by heating the disc to a temperature close to the change in optical properties of a material whose optical properties change with thermal energy, and irradiating the heated portion with a laser beam. An optical information device characterized by erasing a signal. 2. An optical information device according to claim 1, characterized in that a first laser is used as the heating means, and a second laser beam modulated by an erasing signal is irradiated as the erasing means. 3. In the statement of claim 1, the signal recorded on the disk is erased, and one laser first irradiates unmodulated laser light to heat the disk, and then erases the erased signal. An optical information device characterized by erasing signals recorded on a heating disk by irradiating laser light modulated by