JPS5938932A - Digital laser recording method - Google Patents

Abstract

PURPOSE:To eliminate the track matching in a reproduction mode and to simplify the constitution of a device, by contriving the recording method when the digital recording is carried out by means of the laser light. CONSTITUTION:A recording medium 9 is shifted toward an arrow B along the surface of the medium 9 while vibrating a scanning mirror 4 in the direction of an arrow A with a fixed amplitude and a fixed cycle. As a result, a wave- shaped record pattern 10 is obtained. In this case, the feeding speed of the medium 9 is controlled together with the deflecting width and its cycle of the light beam due to the driving of the mirror 4, and the laser light given from a laser light source 1 is turned on and off in response to the information signal. Thus a rectangular record pattern is obtained. Such a record pattern is formed, and the beam amplitude is increased to some extent in a record mode. As a result, the track matching is not required in a reproduction mode. This simplifies the constitution of a device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for recording digital information such as calculated data, personal identification signals, audio signals, etc. onto a recording medium using a laser beam. be.

Conventional Structures and Problems Conventionally, there are optical discs, optical cards, optical films, etc. that record using laser light.

The method for recording information on an optical disc is to record information in the form of dots by turning the light on and off while rotating the disc. An optical card has been proposed as a recording member using a similar optical recording material, but the recording method on this optical card is to turn the recording light beam on and off while moving the card along a plane, thereby recording dots. It was recorded in the form.

These dot-shaped signals are recorded in microns, so when reproducing the signals, an extremely high-precision positioning technique is required between the reproduction light beam and the recorded dot-shaped signals. Therefore, a servo device for focusing the light beam and a servo device for track alignment are required, which makes the reproducing device complicated.

On the other hand, when recording on film, the laser beam is scanned with an optical polarization of 18[T] while the film is running, and the strength of the signal corresponds to the width of the scan, or the intensity of the laser beam is adjusted to a constant value during scanning. It is necessary to adjust the strength of the signal to the full extent.

However, these are all analog recordings,
This is essentially the same as analog recording using a conventional Lang light source, and the reproduction method is also read as analog information.

Purpose of the Invention The purpose of the present invention is to provide a digital laser recording method that eliminates the need for track alignment during playback and simplifies the device by improving the recording method for digital recording using laser light. There is a particular thing.

Structure of the Invention The digital laser recording method of the present invention is configured to converge a light beam from a laser light source onto a recording medium and automatically connect points on the surface of the recording medium, and The optical head configured to scan the optical beam in a uniaxial direction on the surface of the whale medium or the recording medium is moved in parallel in a direction orthogonal to the scanning direction of the optical beam, and the optical beam is scanned once. By performing the above scanning and blinking the light beam from the laser light source in accordance with the digital information to be recorded, a rectangular signal is recorded.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows an embodiment of the present invention, in which an optical head includes a laser light source 1. Collimator lens 2.
Polarizing beam splitter 3, scanning mirror 4, 3
Wave plate 6. Objective lens 6° Focus error signal detector 7
and an objective lens driving magnet 8.

A linearly polarized light beam emitted from a laser light source 1 is converted into a parallel beam by a collimator lens 2, and most of the light is transmitted by a polarizing beam splitter 3. The light beam is further reflected by a scanning mirror 4.

% wave plate 5 to circularly polarized light, and then an objective lens 6.
The light is then focused on the surface of the recording medium 9 as a spot.

The light reflected by the recording medium 9 passes through the acoustic wave plate 6 through the completely opposite path, and then becomes DC polarized light rotated by 90 degrees from the time of incidence, and is reflected by the polarizing beam splitter 3. A focus error signal detector 7 detects the focal position from this reflected light.

By feeding it back, the magnet 8 for driving the objective lens i is actuated. The recording operation at this time is as shown in FIG. 2, when the recording medium 9 is moved in the direction of the arrow along the medium surface while the scanning mirror 4 is vibrated in the direction of the arrow with a constant amplitude and a constant circumference. , a wave-shaped recording pattern 10 is obtained. At this time, by adjusting the feeding speed of the recording medium, the deflection width of the light beam by driving the scanning mirror 4, and its period, and turning the laser beam on and off in accordance with the information signal, recording as shown in Fig. 3 is achieved. A pattern is obtained. When reproducing this, it was necessary to perform track alignment on the submicron order on the dot recording platform as in the past, but according to this embodiment,
By widening the amplitude of the beam during recording to some extent, track alignment is not required at all and the apparatus can be simplified.

In the above description, in order to efficiently detect the focus error signal, a combination of the polarizing beam splitter 3 and the acoustic wave plate 5 is shown, but it is also possible to use a shear half mirror instead of these. It was a cabinet.

Although a scanning mirror has been shown as an optical polarizer for scanning light, it is also effective to use an acousto-optic optical deflector or the like.

Specifically, the laser light source 1 has an output of 16 mW.

A live conductor laser with a wavelength of s3omm was used. after that.

Numerical aperture 0.28. Effective visual field yノ' 1, 4 +IImφ
1 working distance 4.5 It is made into a parallel beam with 6 long axes and 4 short axes through a brain collimator lens 2, and after passing through a polarizing beam sinter 3, a scanning mirror with a tracking frequency of 200 Hz and a maximum deflection angle of 2° 4 makes the optical axis f 90'
Rotate 830% to wavelength of 65% through wave plate 5, 65. Valid! ? O,e iml+, 1.3p with the objective lens 6 with a working distance of 1.3 mm
A beam sporatra of m×2 pm was obtained. At this time, the transmission efficiency of the entire optical system was 32%, and the transmission efficiency was 5 m on the medium surface.
An output of W was obtained. Furthermore, the width of the beam on the medium surface by driving the scanning mirror 4 is at most 0.
．． It was 8 sore throat. 'On the other hand, the recording medium is 86rrrIn×
A 64 mm thick card-shaped plastic plate having a thickness of IM and a mixture of nitrocellulose and a metal complex salt in a ratio of 1:1 (weight ratio) was used.

Using these recording media and optical systems, recording medium feeding speed i'f-o, 7"/SeC + scanning mirror frequency 100 Hz, scanning [1] 0.6 rtr
As a result of recording at m, the recorded C turn shown in FIG. 4 was obtained.

At this time, the signals used were F2F modulated signals of 1, 0, 1, 0.1.0, . . . .

The signal recorded in this way was set to the laser output of the recording optical head of f 2 m V/, the scanning mirror was rotated without any particular track alignment, and the recording medium feeding speed was set to Q, 4 m/Sec. As a result of detecting the focus error signal and feeding it, and also detecting the information signal, amplifying it and converting it to TTL level,
A waveform shown in FIG. 6 was obtained.

Effects of the Invention As is clear from the above embodiments, if the recording method according to the present invention is used, there is no need for trunk alignment during playback, which has the advantage of simplifying the playback optical head and circuit system. death.

It is particularly effective in fields that require a large number of playback devices in addition to recorders, such as automatic ticket gates and person verification at terminal devices.

[Brief explanation of the drawing]

FIG. 1 is an explanatory block diagram of an optical system to which the present invention is applied, and FIG. 2 is an explanatory diagram of its operation during recording. 3 and 4 are recording pattern diagrams, and FIG. 5 is a reproduction output waveform diagram thereof. 1... Laser light source, 2... Collimator lens. 3...Polarized beam sinter 14...
・Scanning mirror, 5...K wavelength plate, 6...
...Objective lens. 7...Focus error signal detector, 8...
...Objective lens driver @ magnet, 9...Recording medium. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] The light beam from the laser light source is configured to be focused on the recording medium and automatically focused on the surface of the recording medium, and the light beam is scanned in a uniaxial direction on the surface of the recording medium. The configured optical head or recording medium is moved in parallel along the surface of the recording medium in a direction orthogonal to the scanning direction of the light beam, and at the same time, the light beam is scanned one or more times to form a single piece of information to be recorded. A digital laser recording method characterized by recording by blinking a laser beam according to digital information.