JP2599352B2 - Optical information recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical information for optically writing information on a disk-shaped recording medium (hereinafter, referred to as a "disk") represented by a video disk or a compact disk. It relates to a recording device.

2. Description of the Related Art A conventional information recording apparatus for writing information on a disc, such as a video disc, will be described with reference to FIG. The disk 1 is like a glass disk. A photosensitive agent such as a resist 2 is applied on the disk 1, and the disk 1 is driven to rotate by a motor 3. Recording laser 4 (for example, Ar ⁺
The light beam A emitted from the laser) is the light modulator 5, the lens
6, slit 7, lens 8, beam splitter 9, mirror 10,11
Then, the light is incident on the objective lens 12, and the objective lens 12 irradiates the point a on the disk 1 with the focal light. However, the distance between the objective lens 12 and the disk 1 changes due to the inclination and warpage of the disk 1 and the unevenness of the disk surface, and the focus is not always located on the disk surface a.

Therefore, an automatic focus control device is required. Laser 13
The light beam B emitted from (for example, a He-Ne laser) is a lens 14, a polarizing beam splitter 15, a λ / 4 plate 16, and a mirror 11.
And enters the objective lens 12. At this time, the light beam B emitted from the laser 13 does not expose the resist 2. The mirror 11 has a characteristic of transmitting the light beam A but reflecting the light beam B. The light beam B reflected at the point a on the disk 1 has an objective lens 12, a mirror 11, a λ / 4 plate
16, 2 split detector 1 through polarizing beam splitter 15
It is incident on 7. The movement of the light beam B 'incident on the two-segment light detector 17 is in the direction of the arrow shown in FIG. The output of the split optical detector 17 is applied to a differential amplifier 18. The output of the differential amplifier 18 is a control circuit
Applied to the linear motor 20 through 19. The linear motor 20 vibrates the objective lens 12 up and down, and as a result, focuses on the disk surface. The light beam A ′ split by the beam splitter 9 is projected through a lens 21 onto an image sensor 22 such as a CCD camera. The output of the CCD camera 22 is applied to a monitor TV 23, and the size, location, and luminance distribution of the recording light beam can be visually observed. This monitor
FIG. 10 shows the light beam A 'seen on the TV 23. At this time, the light beam A '
Is an elliptical beam.

However, in the conventional recording apparatus, when the light beam emitted from the recording laser 4 fluctuates, it does not pass through the center of the slit 7 and the light beam entering the objective lens 12 There is a disadvantage that the intensity of A is reduced and optical information recording cannot be performed so as to have an appropriate pit shape. FIG. 11 shows the intensity distribution at the point a of the disk 1 when the light beam A fluctuates. FIG. 11a shows the normal state, FIG.
FIGS. B and c show the case where the beam position is shifted.

The present invention has been made in view of this point, and it is an object of the present invention to provide an optical information recording device that can always have an appropriate intensity distribution on a disc and optically record information so as to have an appropriate pit shape. It is the purpose.

Means for Solving the Problems The present invention solves the above problems by providing an imaging device for observing a light beam split by a beam splitter, receiving a video signal from the imaging device, A beam position detection device that detects a position change in a direction perpendicular to the optical axis of a recording light beam from a change in a luminance signal in a video signal before and after a predetermined set time from a horizontal synchronization signal therein, and is driven by an output of the beam position detection device. Actuator
The beam position is controlled by moving the lens on the entrance side of the slit in the first optical system in the direction orthogonal to the optical axis of the light beam passing through the lens by the output of the actuator.

That is, in the present invention, an error signal is generated by observing the movement of the light beam A using a CCD camera, an actuator such as a motor is driven by the error signal, and a lens connected to the actuator is moved. Beam A
Is corrected so that the light beam A always passes through the center of the slit.

Operation The present invention detects the position fluctuation of the light beam A in the direction perpendicular to the optical axis, and moves the lens in the direction perpendicular to the optical axis of the light beam. Can be controlled so that the light beam has an appropriate beam intensity distribution at a point a on the disk.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration diagram of an optical information recording apparatus according to a first embodiment of the present invention. The same components as those of the conventional example shown in FIG. The light beam A 'split by the beam splitter 9 enters the CCD camera 22. At this time, as shown in FIG. 2, the adjustment is performed so that the longitudinal direction of the light beam A 'is located in a direction perpendicular to the horizontal scanning line of the monitor TV23. The output A of the CCD camera 22 is also applied to a sync separation circuit 24 and a clamp circuit 25. Sync separation circuit
24 is a horizontal simultaneous signal (H-
syn) is taken out and applied to the first monomultivibrator 26 as a trigger pulse. The output C of the mono-multivibrator 26 is applied to the second mono-multivibrator 27 as a trigger pulse and also to the analog switch 28 as a gate input. Further, the output d of the second monomultivibrator 27 is applied to another analog switch 29 as a gate input. The video signal E having the pedestal fixed by the clamp circuit 25 is input to the analog switches 28 and 29. Analog switch 2
The outputs 8 and 29 are applied to a differential amplifier 32 through low-pass filters 30 and 31. The output of the differential amplifier 32 is applied to a motor 34 via a control circuit 33. Motor 34 and lens 6
Are mechanically connected, and the lens 6 is moved up and down by the motor 34 to adjust the position of the light beam A.

FIG. 3 shows the output waveform of each part of the first embodiment, and FIG. 4 shows the waveform when the beam position is shifted. 4a and 4c show the case where the beam position is shifted, and FIG. 4b shows the case where the beam position is normal.

FIG. 5 is a block diagram of a second embodiment of the present invention. The light beam A 'passes through the beam splitter 35, the mirror 36, and the lens 21.
Enters the CCD camera 22. The reflected light A "of the light beam A from the disk 1 enters the CCD camera 22 through the objective lens 12, mirrors 11, 10, beam splitter 35, and lens 21. The light beams A ', A" focus on the same position. The beam splitter 35 has a wedge shape so as not to be connected. At this time, a screen appearing on the monitor TV 23 is shown in FIG. The output of the CCD camera 22 is applied to a vertical sync separation circuit 37. The V-syn separated by the vertical sync separation circuit 37 is applied to a third mono-multi vibrator 38. Therefore, a gate signal corresponding to the light beam A 'is generated and applied to the gate 39. As a result, the trigger pulse of the mono-multivibrator 26 is not emitted from a position corresponding to the light beam A ", and the influence of the reflected beam A" from the disk surface is eliminated. FIG. 7 shows the waveform of each part at this time.

Effect of the Invention As described above, by using the present invention, the position fluctuation of the recording laser beam can be suppressed and the beam position fluctuation can be detected from the video signal of the CCD camera observing the beam shape. In particular, there is no need for a new mechanism or light-receiving element for detecting position fluctuations, and it has the advantage of being able to electrically detect beam position deviations from video signals output by CCD cameras conventionally provided for visual observation. .

[Brief description of the drawings]

FIG. 1 is a block diagram of an optical information recording apparatus according to a first embodiment of the present invention, and FIG.
FIG. 3 is a schematic diagram showing the upper light beam A ', FIG. 3 is an output waveform diagram of each unit in the device, FIG. 4 is a waveform diagram of an error signal when the beam is shifted in the device, and FIG. FIG. 12 is a block diagram of an optical information recording apparatus according to a second embodiment,
The figure shows the light beams A 'and A "on the monitor TV in the same device.
FIG. 7 is an output waveform diagram of each unit in the device, FIG. 8 is a block diagram of a conventional optical information recording device,
FIG. 9 is a schematic diagram showing the movement of a light beam B on the optical detector of the device, FIG. 10 is a schematic diagram showing a light beam A 'on a monitor TV of the device, and FIG. FIG. 4 is a waveform diagram showing an intensity distribution of a light beam incident on the light source. 4 ... Recording laser, 5 ... Optical modulator, 6,8,12,14 ...
Lens, 7 Slit, 9 Beam splitter, 22
… CCD camera, 24… Sync separation circuit, 25… Clamp circuit, 26, 27… Mono multivibrator, 28, 29… Analog switch, 30, 31… Low-pass filter, 32…
Differential amplifier, 33 control circuit, 34 motor, 35 beam splitter, 36 mirror, 37 vertical sync separation circuit, 38 mono multivibrator, 39 gate circuit.

Claims (2)

(57) [Claims] 1. A radiation source, a light modulator for intensity-modulating a light beam emitted from the radiation source, a first optical system including a lens and a slit for shaping the light beam intensity-modulated by the light modulator. A lens for converging and irradiating the light beam shaped by the first optical system onto the disc-shaped record carrier, a second optical system including a mirror, and a rotation drive device for driving the disc-shaped record carrier to rotate; An automatic focus control device for always focusing the light beam on the disc-shaped record carrier, a beam splitter for splitting the light beam emitted from the first optical system, and a beam splitter for splitting the light beam. An imaging device for observing the reflected light beam, a video signal from the imaging device, and a luminance signal in a video signal around a predetermined set time from a horizontal synchronization signal in the video signal. A beam position detecting device for detecting a position change of the recording light beam in a direction perpendicular to the optical axis from the change, and an actuator driven by an output of the beam position detecting device, wherein a slit in the first optical system is output by the actuator. An optical information recording apparatus, wherein a beam position is controlled by moving a lens on an incident side of the light beam in a direction orthogonal to an optical axis of the light beam passing through the lens. 2. A beam position detecting device comprising: a horizontal synchronizing separation circuit and a clamp circuit for receiving a video signal from an imaging device; a first monomultivibrator for receiving a horizontal synchronizing signal output from the horizontal synchronizing and separating circuit; A second monomultivibrator receiving an output of the first monomultivibrator, a first analog switch receiving an output of the clamp circuit and receiving an output of the first monomultivibrator as a gate input; A second analog switch receiving the output and receiving a second monomultivibrator output as a gate input; first and second low-pass filters receiving the outputs of the first and second analog switches; 2. The method according to claim 1, wherein the differential amplifier receives an output from the first and second low-pass filters. The optical information recording apparatus as set forth in claim 1, wherein.