JPS5922292B2 - Kogaku Tekikiki Rokusai Seisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording and reproducing apparatus that reproduces recorded information by irradiating a light beam onto a photosensitive recording medium capable of recording information by irradiating it with a light beam. This is intended to prevent the medium from being erroneously recorded or erased due to the operating state of the device.

In general, recording materials that can be recorded by irradiation with a light beam of intensity above a certain level include those that use thermal flexibility such as plastic thermistors, and those that use phase transition such as amorphous semiconductors.

Information can be recorded, reproduced, and erased on these materials by controlling the intensity of light energy applied to them. FIG. 1 shows a general configuration of an apparatus for recording and reproducing information on a disc-shaped recording medium using these materials. In FIG. 1, 1 is a light source such as a laser, and 2 is an optical modulator, which modulates incident light a based on a signal input from a terminal 3 to generate output light b. 4 is a projection lens that magnifies the incident light b and
The image is projected onto an objective lens T, which will be described later.

5 is a total reflection mirror that changes the direction of the optical path.

6 is a beam splitter.

Reference numeral 7 comprises an objective lens of a microscope, etc., which narrows the incident light b to a small size and irradiates it onto the recording disk 8.

This recording disc 8 is a disc-shaped base material coated with the photosensitive recording material. Reference numeral 9 indicates a motor that rotates the recording disk 8.

Light c represents light reflected from the surface of the recording disk 8, and is used for reading information, controlling the focus of the objective lens 7, or controlling the tracking of information tracks. When recording, reproducing, and erasing information with the configuration shown in FIG. 1, it is necessary to supply optical energy to the recording disk with an intensity that matches the properties of the recording material according to each mode.

That is, it is necessary to select the irradiation energy in consideration of the light energy during reproduction, the light energy during recording, the light energy during erasing, the light energy that may damage the recording material due to evaporation, etc. That is, reproducing recorded information using light having recording energy must be avoided because it involves deterioration of the recording material. Generally, the following relationships exist between the above energies. Reproduction energy〈recording energy〈erase energy〈damage energy.

Furthermore, the energy absorbed by the recording material depends not only on the irradiated light energy but also on the rotational speed of the recording disk 8, that is, the speed at which the irradiated light traverses.

That is, the energy absorbed by a point on the recording material is related to the intensity of the irradiating light, the speed at which the point passes under the irradiating light, and the speed at which the point dissipates the absorbed energy. Therefore, even when the information reproducing light having the weakest optical energy is irradiated, if the disk 8 is stationary, the irradiated area may absorb energy exceeding the damage energy and cause local destruction. be. The above indicates that erroneous recording due to reproduction light and erroneous erasure due to reproduction light may occur.

It also shows that erroneous erasure or destruction due to recording light may occur. Furthermore, even when the disc 8 is in a rotating state, a mistake in the irradiation energy may cause the above-mentioned malfunction, which may prevent the recording disc 8 from operating normally. This can be a decisive flaw in ensuring reliability when the above recording material is used as a storage device.

The present invention aims to prevent the occurrence of unintended malfunctions in the recording/reproducing apparatus as described above.

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 2, the same components as in FIG. 1 are given the same numbers. In FIG. 2, a shutter 10 is inserted into the optical path from the light source 1 to the recording disk 8 to block the recording disk 8 from being irradiated with light.

Sl, S2, and S are switches for specifying the operating mode of the recording/reproducing apparatus. S1 specifies reproduction of recorded information, S specifies new recording of information, and S3 specifies deletion of information. Reference numerals 11, 12, and 13 are circuits that generate DC voltages according to the operations of the corresponding switches S, S2, and S3.

DC voltages from these circuits 11, 12, 13 are applied to the optical modulator 2. For example, in an ultrasonic modulator using glass, the acoustic power is controlled using the DC voltage, and the intensity of the output zero-order light is controlled by known means. That is, a light beam b having a required intensity is obtained according to each operation mode of reproduction, recording, and erasing. In addition, as a method of obtaining light beams with different intensities as described above, it is also possible to change the transmittance of a filter inserted in the optical path by operating each of the above switches or by changing the voltage and current corresponding to the operation of each switch. Can be implemented.

Reference numeral 14 denotes a device for measuring the intensity of the light beam b/ that is reflected by one surface of the beam splitter 6, and is composed of, for example, a solar cell and an amplifier.

An electrical signal corresponding to the intensity of the light b/ is obtained from the output line of the measuring device 14. A first comparator 15 compares the electrical output signal of the measuring device 14 with a reference value A1 and generates an output on the output line when the electrical output signal is smaller than the reference value A1;
is a second comparator which compares the output signal of the measuring device 14 with the reference value A2, A, and generates an output on the output line if it is larger than the reference value A2 or smaller than the reference value A2, and 1r is the comparator. 16, the output signal of the measuring device 14 is set to the reference value A4,
a third comparator 18 which generates an output on the output line if it is greater than the reference value A4 and smaller than the reference value A;
19 and 20 are AND gate circuits.

The AND gate circuit 18 generates an output on the output line when the reproduction command switch S, is turned on and the intensity of the light beam b' is smaller than the reference value A1. Similarly, the AND gate circuit 19 has the recording command switch S, turned on,
- Moreover, when the intensity of the light beam b' is greater than the reference value A2 and smaller than the reference value A, an output is generated on the output line m.
The AND gate circuit 20 generates an output on the output line n when the erase command switch S is pressed and the light beam b' is greater than the reference value A and smaller than the reference value A.
That is, the comparators 15, 16, 17 and the AND gate circuits 18, 19, 20 check whether the necessary optical energy is supplied to each of them depending on the operation mode of the recording/reproducing apparatus. Reference numeral 21 denotes an OR (0R) gate circuit which generates an output on output line 0 when an output exists on any of the output lines 1, m, and n of the AND gate circuits 18-20.

A circuit 23 detects the rotation of the motor 9, that is, the rotation of the disc-shaped recording medium 8, and generates an output upon detecting that the motor 9 is rotating at a speed within a normal range.

This detection circuit 23 detects that when the disk-shaped recording medium 8 coated with a photosensitive recording material is not rotating at the normal speed, light may be irradiated by mistake and excessive light may cause the recording material to malfunction. It is intended to prevent 22 is an AND gate circuit, which generates an output when an output exists in each of the 0R gate circuit 21 and the rotation detection circuit 23, drives the shutter drive circuit 24, removes the shutter 10 from the optical path,
The disc-shaped recording medium 8 is irradiated with light having an intensity corresponding to the operating mode, and the recording/reproducing apparatus is operated.

By controlling and confirming the intensity of the irradiated light as described above, recording, reproducing, and erasing of information can be performed reliably without error. Although 10 is described as a shutter in FIG. 2, a disk-shaped recording medium 8 coated with a recording material
It may also be a filter means that passes a weak amount of safe light that does not cause any change in the recording material in a stationary state. In this case, the position of the irradiation light on the recording material can be searched using the weak light, or the position of the disc-shaped recording medium 8 and the objective lens 7 can be searched.
It can also be used to measure whether the distance to the object is within the depth of focus of the optical system. As described above, according to the present invention, for example, during reproduction, the light beam intensity does not increase for some reason and the recorded information is not damaged due to a recording state, and the rotational speed of the recording disk decreases. Similarly, recorded information will not be damaged.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional optical recording and reproducing apparatus, and FIG. 2 is a block diagram of an optical recording and reproducing apparatus according to an embodiment of the present invention. 1... Light source such as a laser, 2... Light modulation element, 4... Projection lens, 5... Total reflection mirror, 6...・Beam splitter, 7...
...Objective lens, 8... Recording disc, 9...
...Motor, 10... Uyatsuta 11, 12, 1
3...DC voltage generation circuit, 14...Light intensity measuring device, 15, 16, 17...Comparison circuit, 18, 19, 20, 22...・AND circuit, 2
1...0R circuit, 23...Motor operation detection circuit, 24...Uyatsuta drive circuit, S1
...Reproduction command switch, S2 ... Recording command switch, S3 ... Erase finger ◆ switch.

Claims (1)

[Claims] 1 Record information by irradiating a recording disc with a light beam with an intensity of more than the predetermined value onto a recording disk capable of recording information by irradiating the light beam with an intensity of more than the predetermined value, and record the information with a light beam with an intensity of less than the predetermined value. In an optical recording and reproducing apparatus that reproduces recorded information by irradiating a light beam, means for selectively changing the intensity of a light beam to a beam intensity within a predetermined range according to a selected operation mode; a first detection means for detecting the intensity of the beam, and detecting whether the intensity of the detected light beam is within the predetermined beam intensity range and indicating that it is outside the range; a second detection means that outputs a second detection signal; and a third detection means that detects the rotational speed of the recording disk and outputs a third detection signal when the rotational speed is less than or equal to a predetermined rotational speed. , an optical recording/reproducing apparatus comprising: means for obtaining a logical sum signal of the second and third detection outputs; and means for blocking or attenuating the light beam irradiated onto the recording disk based on the logical sum output.