JPS61192038A - Optical information recorder - Google Patents

Abstract

PURPOSE:To always secure a proper intensity distribution and a proper bit form on a disk by observing the movement of a light beam A through a CCD camera for production of an error signal and moving a lens with said error signal for correction of the movement of the beam A to make the beam A pass the center of a slit at all times. CONSTITUTION:The output (a) of a CCD camera 22 is supplied to a synchronizing separator 24 and a clamp circuit 25. The circuit 24 extracts the horizontal synchronizing signal H-syn (b) excluding a vertical blanking period and applies it to the 1st monostable multivibrator 26 as a trigger pulse. The video signal (e) whose pedestal is fixed by the circuit 25 is supplied to analog switches 28 and 29. The outputs (f) and (g) of switches 28 and 29 are applied to a differential amplifier 32 via LPF 30 and 31. While the output (h) of a differential amplifier 32 is applied to a motor 34 via a control circuit 33. The motor 34 is coupled mechanically to a lens 6 and therefore the lens 6 is moved up and down by the motor 34. Thus the position of a light beam A is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to disc-shaped recording media (hereinafter referred to as "disc") such as video discs and compact discs.
This article relates to an optical information recording device that optically writes information to a computer.

BACKGROUND OF THE INVENTION A conventional information recording device for a video disc or the like that writes information on a disc will be described with reference to FIG. The disk 1 is like a glass disk, and a photosensitive agent such as a resist 2 is applied onto the disk 1, and the disk 1 is rotated by a motor 3.

A light beam emitted from a recording laser 4 (for example a laser) is connected to a light modulator 5. Lens 6, slit 7, lens 8. Beam splitter9. The light enters the objective lens 12 through the mirror 10.11, and is focused by the objective lens 12 onto a point a on the disk 1. However, the inclination and warpage of the disk 1.

Due to the unevenness of the disk surface, the objective lens 12 and the disk 1
The distance between them changes, and the focal point is not always located on the disk surface a.

For this reason, an automatic focus control device is required. Laser 13
The light beam B emitted from the lens 14 (for example, a He-No laser). Polarizing beam splitter is, 7'4 plate 16. The light passes through the mirror 11 and enters the objective lens 12 . At this time, the light beam B emitted from the laser 13 is applied to the resist 2.
The mirror 11 has a characteristic of not exposing the light beam B to light, and allowing the light beam B to pass through the mirror 11, but reflecting the light beam B. The light beam B reflected at point a on the disk 1 passes through the objective lens 12. Mirror 11, /4 plate 16. The light passes through the polarizing beam splitter 16 and enters the two-split detector 17 . The movement of the light beam B' incident on the two-split optical detector 17 is in the direction of the arrow shown in FIG. 9 as the disk surface moves up and down. The output of the two-split photodetector 17 is applied to a differential amplifier 18. The output of the differential amplifier 18 is the control circuit 1
9 to the linear motor 20. This linear motor 2° causes the objective lens 12 to vibrate up and down, and as a result, it comes to focus on the disk surface. The light beam 5' split by the beam splitter 9 passes through a lens 21 and is projected onto an image pickup device 22 such as a COD camera. The output of the CCD camera 22 is applied to a monitor TV 23, so that the size, location, and brightness distribution of the recording light beam can be visually observed. The light beam seen on this monitor TV23 is 5'
is shown in FIG. 10. At this time, the light beam 5' becomes a circular beam due to the effect of cutting a part of the beam 5 at the end of the slit.

Problems to be Solved by the Invention However, in conventional recording apparatuses, when the light beam emitted from the recording laser 4 fluctuates, it does not pass through the center of the slit and enters the objective lens 12. . The disadvantage is that the intensity of the light beam decreases, making it impossible to optically record information with an appropriate bit shape.

FIG. 11 shows the intensity distribution at point a of the disk 1 when the light beam sways. FIG. 11a shows a normal state, and FIGS. 11a and 11c show a case where the beam position is shifted.

The present invention has been made in view of this point, and an object of the present invention is to provide an optical information recording device that can record optical information so that the disk always has an appropriate intensity distribution and an appropriate bit shape. That is.

Means for Solving the Problems In order to solve the above problems, the present invention provides a beam position detection circuit that detects a change in the position of a light beam person from the output of an image sensor such as a COD camera, and a beam position detection circuit that detects a change in the position of a light beam person. The beam position is controlled by moving the lens vertically according to the output of the beam position detection circuit. It was designed to do so.

One! B. The present invention uses a COD camera to observe the movement of a person with a light beam and generates an error signal, and this error signal drives an actuator such as a motor to move a lens connected to this actuator. The feature is that the movement of the beam person is corrected so that the light beam person always passes through the center of the slit.

Operation The present invention has the above-mentioned configuration, so that even if the position of the light beam person changes, the change in the position of the light beam person is detected, and by moving the lens, the light beam person always passes through the center of the slit, and the position of the light beam person is constantly passed through the center of the slit. The light beam can be controlled to have an appropriate beam intensity distribution at point a.

EXAMPLES Hereinafter, examples of the present invention will be described based on the drawings.

FIG. 1 shows a configuration diagram of an optical information recording apparatus according to a first embodiment of the present invention, and the same components as those in the conventional example shown in FIG. 8 are given the same numbers and their explanations will be omitted. The light beam split by the beam splitter 9 is connected to the CCD camera 22.
incident on . At this time.

Adjustment is made so that the longitudinal direction of the light beam ' is located in the horizontal scanning line direction of the monitor TV 23 as shown in FIG.

The output of the CCD camera 22 is also applied to a synchronization separation circuit 24 and a clamp circuit 26. The synchronization separation circuit 24 receives the horizontal synchronization signal (H-5yn) excluding the vertical blanking period.
The mouth is removed and applied as a trigger pulse to the first mono-multivibrator 26. The output of the mono-multivibrator 2e is applied as a trigger pulse to the second mono-multivibrator 27, and also as a gate input to the analog switch 29. The video signal H whose pedestal is fixed by the clamp circuit 26 is input to analog switches 28 and 29. The outputs of analog switches 28, 29 and E are low pass filters 30.
31 and is applied to the differential amplifier 32. Differential amplifier 3
The output of No. 2 is applied to the motor 34 via the control circuit 33. The motor 34 and the lens 6 are mechanically connected, and the motor 3
4 moves the lens 6 up and down to adjust the position of the light beam person.

FIG. 3 shows the output waveforms of each part of the first embodiment, and FIG. 4 shows the waveforms when the beam position is shifted.

FIGS. 4 & C show a case where the beam position is shifted, and FIG. 4 shows a normal state.

FIG. 5 is a block diagram of a second embodiment of the present invention.

Beam splitter 35. Mirror 36. The light beam A' passes through the lens 21 and enters the CCD camera 22 .

The light beam A reflected from the disk 1 enters the CCD camera 22 through the objective lens 12, mirror 11, 10, beam splitter 36, and lens 21.
The beam splitter 36 is wedge-shaped so that the beams ' and A' are not focused on the same position. At this time, the monitor T
The output of the 3CCD camera 22, whose screen appears on V23 is shown in FIG. 6, is applied to a vertical synchronization separation circuit 37. The "i-syn" separated by the vertical synchronization separation circuit 37 is applied to a third mono-multivibrator 38. There, a gate signal corresponding to the light beam signal is generated and applied to the gate 39. The trigger pulse of the mono-multivibrator 26 is not emitted from the part corresponding to the beam λ'', and the influence of the reflected beam 5'' from the disk surface is eliminated.The waveforms of each part at this time are
As shown in the figure.

Inventive effect By using the present invention as described above.

In addition to suppressing positional fluctuations of the recording laser beam.

This is because the beam position fluctuations are detected from the video signal of the CGD camera that observes the beam shape.

In particular, it has the advantage that a mechanism and a light receiving element for detecting positional fluctuations are not required.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an optical information recording device according to a first embodiment of the present invention, and FIG. 2 is a block diagram of a monitor T in the same device.
A schematic diagram showing the light beam A' on V, FIG. 3 is an output waveform diagram of each part in the same device, FIG. 4 is a waveform diagram of an error signal when the beam is shifted in the same device, and FIG. 5 is a diagram of the present invention. the second of
FIG. 6 is a schematic diagram showing the optical beam beams on a monitor TV in the same device, FIG. 7 is an output waveform diagram of each part in the same device, and FIG. The figure is a block diagram of a conventional optical information recording device, FIG. 9 is a schematic diagram showing the movement of the light beam B on the optical detector of the same device, and FIG. 10 is a schematic diagram showing the movement of the light beam B on the monitor TV of the same device. FIG. 4 is a waveform diagram showing the intensity distribution of the light beam incident on the 111 iri′ point and the COD. 4. Recording laser, 5. Optical modulator, 6.B. 12.14...Lens, 7...Slit, 9...Beam splitter%22-...
・GCD camera, 24... Synchronization separation circuit, 26
... Clamp circuit, 26゜27 ... Mono multivibrator, 28, 29 ... Analog switch, 30, 31 ... Low pass filter, 32. ... Differential amplifier, 33 ... Control circuit, 34 ... Motor, 36 ... Beam splitter. 3e...Mirror, 37...Vertical synchronization separation circuit. 38... Mono multivibrator, 39...
...Gate circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Fig.
Anzu J2 hydraulic power Figure 8 Figure 9 Figure 11

Claims (3)

[Claims] (1) a first optical system comprising a radiation source, an optical modulator that modulates the intensity of the light beam emitted from the radiation source, a lens and a slit that shapes the light beam intensity-modulated by the optical modulator; a second optical system comprising a lens and a mirror for focusing the light beam shaped by the first optical system onto the disk-shaped recording medium; and a rotation control device for rotationally driving the disk-shaped recording medium. , an automatic focus control device for always focusing the light beam on the disc-shaped recording medium; a beam splitter for splitting the light beam emitted from the first optical system; an imaging device for observing the divided light beam; a beam position detection device that receives a video signal from the imaging device and detects positional fluctuations of the recording light beam; and is driven by the output of the beam position detection device. 1. An optical information recording device comprising an actuator, and configured to control a beam position by moving a lens on an incident side of a slit in the first optical system using an output of the actuator. (2) The beam position detection device includes a horizontal synchronization separation circuit and a clamp circuit that receive a video signal from an imaging device, a first mono-multivibrator that receives a horizontal synchronization signal output from the horizontal synchronization separation circuit, and a first mono-multivibrator that receives a horizontal synchronization signal output from the horizontal synchronization separation circuit. a second mono multivibrator receiving the output of the first mono multivibrator; and a first mono multivibrator receiving the output of the clamp circuit and receiving the output of the first mono multivibrator as a gate input.
a second analog switch that receives the output of the clamp circuit and receives the output of the second mono multivibrator as a gate input;
Claims characterized by comprising: first and second low-pass filters that receive the outputs of the analog switches; and a differential amplifier that receives the outputs from the first and second low-pass filters. The optical information recording device according to item 1. (3) The beam position detection device includes a horizontal synchronization separation circuit, a clamp circuit, a vertical synchronization separation circuit that receives the video signal from the imaging device, and a third component that receives the vertical synchronization signal output from the vertical synchronization separation circuit. 3. The optical information recording apparatus according to claim 2, comprising a multivibrator and a gate circuit receiving an output from the third mono-multivibrator and a horizontal synchronization separation signal.