KR820001631B1 - Video disc players - Google Patents

Abstract

In the dise player, the light soyrce(3) generates radiative interpretation ray-flux (4 which collides against the surface(7) of disc(5), the optical system(2) comprised of a pair of mirror(26,28) makes the ray-flux go straight, and a detector receives modulated radiative ray-flux from information track.

Description

Video disc player

1 is a general group diagram of a video disc player.

2 is a schematic diagram of the optical system illustrated in FIG.

2 is an enlarged view of the surface of the disk illustrated in FIG.

3 is a partial weak side view of a reproducing apparatus showing another example of the present invention.

4 is a partial weak side view of a read head.

5 is a schematic of a radial tracking system.

FIG. 6A is a schematic of a spindle servo system. FIG.

6b is a schematic of a tangential servo system.

6C is a schematic of a carriage servo system.

7 is a perspective view of a cam and camcorder follower for adjusting read beam focus on an information track in the video disc element illustrated in FIG.

FIG. 8 is an enlarged side view of the optical head and air bearing device used in the video disc player illustrated in FIG.

9 is a detailed view of the signal recovery circuit and the mirror reflection control circuit illustrated in FIG.

FIG. 10 is a schematic diagram illustrating a pair of mirrors formed on a converging surface used for the player illustrated in FIG.

The present invention continuously configures the reflection and sub-reflection ranges on a plurality of information tracks formed on a video disc, reads frequency modulated video signals accumulated therein, and directs the read flux to collide with the information track. The present invention relates to a video disc player having an optical system capable of condensing a reflected signal modulated by a reflection and an antireflection range.

A frequency-modulated signal is recovered from the signal modulated by the reflected light and sent to the signal processing portion for application to a standard television receiver or monitor. A signal modulated by the recovered light is sent to a plurality of servo systems to generate a control signal. The control signal is used to adjust the lens to an appropriate focal position with respect to the information recording surface of the video disc and simultaneously adjust the focus of the beam. By keeping it in place, the focused light spots collide with the center of the information track.

Accordingly, the present invention relates to a video disc player operable to recover a frequency modulated video signal from an information recording surface of a video disc, wherein the frequency modulated video information is accumulated in a plurality of concentric circles formed in the information recording portion of the video disc surface.

The frequency modulated video signal is represented by a display element in which track shapes on the information recording surface portion of the video disc are arranged in one place. The display element is constructed by continuously arranging the specular reflection and specular antireflection ranges on the information track.

A laser is used as a light beam source and an optical system is used to adjust the focus of the beam at a point having a diameter almost equal to the width of the information display element located on the information track. Microscope objectives are used to control the focus of the readout beam at the point and also to concentrate the reflected light at points that collide with the continuously arranged light reflection and light nonreflection ranges.

By applying the output of the microscope lens to the signal recovery system, it is used primarily as an information recording light element of the reflected beam, and at the same time, as a control signal source for generating a radial tracking secondary signal and a focus error signal. do.

The information recording portion of the recovered frequency modulated video signal is sent to a frequency modulation processing system to be operated before being delivered to a receiver or TV monitor of a standard TV.

The control part of the recovered frequency-modulated video signal is applied to a number of servo subsystems to control the position on the read line speed at the center of the information track and to collect the maximum reflected light when the lens is in the proper focus position. To control. The tangential servo subsystem is used to control the time-base error introduced in the reading process due to the mechanical operation of the reading system. This time axis error appears as a phase error in the recovered frequency modulated video signal. By applying the phase error to the mirror moving in the tangential direction, it adjusts the position where the focused focus impacts the information track. The tangential mirror moves the light spot along the information track back and forth to make the same correction of the detected phase error.

Broadly speaking, a tangential mirror is a device used to correct the time axis error by adjusting the time axis for a signal read from a video disk element.

Radial Tracking Servo subsystems are used to keep track of the point of focus on the information track radially, which responds by controlling the signal portion of the recovered frequency modulated signal, from the center of the track position to the actual position. Generate an error signal indicating the residual deviation.

This tracking error is used to control the movement of the radial tracking mirror so that the light spot returns to the center of the track position.

The carriage servo subsystem uses a closed loop operation to move the carriage to a specific location on the current generator side. This subsystem corrects irregular radial tracking of information tracks by controlling the relative movement of video disks and the speed of the readout at constant speed. The current generator is a device for continuously supplying bias current to move the carriage device at a constant speed in a constant direction.

The carriage tachometer current generator is mechanically connected to the carriage motor to generate a current representing the instantaneous speed of the carriage motor. The current coming from the carriage tachometer can be compared with the current generated from the power supply of the additive operation.

The addition operation circuit detects the difference between the current generated by the current generator and the current generated by the carriage tachometer and applies a differential signal to the power amplifier to move the carriage device under the control of the current generator.

The spindle type servo circuit rotates the spindle and the video disc elements mounted on the spindle at a constant rotational speed. A feedback loop is used to ensure that the rotation speed does not deviate from the highly accurate reference frequency.

In the embodiment of the present invention to provide a plurality of reflection warnings by using a pedestrian mirror in conjunction with the secondary mirror. A small amount of mirror movement may be required to shift the collision point of the radiant light point against the disc by reflecting a large number of reading beams from a highly precise laser light source. In addition, when the reflection occurs a lot, the optical path becomes longer, so that a lens having a long focal length can be used, and the light spot can be directed to the disk, and the focus of the image of the reflected light spot can be adjusted to the photosensitive transmitter.

In addition, another feature of the present invention is that the illumination radiation can be directed to a specific point, and can also convey information from the illuminated light spot to the detection device. Thus, for example, a primary photosensitive pickup can be used as an input to a differential amplifier and fed from the fixed bias source to the differential input. When illuminated by the reflected light spot at the periphery of the track, i.e. the center of the information track, the bias can be adjusted to balance the input of the photodetector. When the radiation intensity to the detector increases in a system where the track is darker than the band between the tracks, a servo signal is generated to drive the mirror in the primary direction so that the light spot moves toward the track and center. Similarly, as the radiation decreases, the bias becomes relatively large, generating an error signal that moves the mirror and light spots in opposite directions, both in the direction away from the track and toward the track's periphery.

A secondary Confucian mirror is constructed to rotate in a secondary direction perpendicular to the radial tracking direction of the image.

This tracking makes it possible to eliminate time-base errors introduced in the tangential direction and introduced by the difference between the timing and synchronization of the recorded information with respect to the time frequency generated in the reproduction circuit.

As is known, TV circuits, especially color TV circuits, require extremely accurate time synchronization to maintain color fidelity and to correct horizontal synchronization. Therefore, the error intervening in the concurrency of the time information recorded on the disc and the local oscillation period of the playback apparatus can be eliminated by moving the mirror in the tangential direction or the secondary direction.

Another improved example is that the bias force required to maintain an air bearing supporting an objective lens at a distance from the disk surface is varied as a function of the surface speed of the disk. Since there is a direct relationship between the relative radial position of the air bearing and the surface velocity, a simple mechanical cam device is used to modify the biasing force acting on the air bearing as a function of the radial position of the regeneration device.

It is therefore an object of the present invention to improve the improved playback apparatus and method, to optically adjust the radiation flux for video discs on which video information is recorded, and to use a pedestrian mirror and a pair of fixed mirrors.

It is also possible to configure a video disc player device so that information recorded on an information track formed on the reflective surface of the video disc element can be read. In the formation of a line-oriented system that propagates the generated reading flux to the information track along the flux path, the reading flux is modulated by the information display and the reading flux is emitted from the information track to form a track. Try to reproject parts. The signal retrieval and detection circuit receives the reflected radiation flux.

The purpose of the present invention is to provide a method for optically scanning a video disk in a folded beam path and a tracking circuit, and also by using an optical path having an incident beam and a reflection beam part. It is another object of the present invention to improve a scanning apparatus and method capable of reproducing information accumulated on a disk.

In further detail, an object of the present invention is to improve a confucian mirror device and method to enable a schematic and fine radial automatic relay control in a video reader in an optical path between a video disk surface and a light source. It is also an object of the present invention to configure the optical path so that the mirror makes the movement small so that the position of the point of radiant energy sheared on the disk surface can be varied widely and the conveyed radiant energy can be transmitted to the detector system.

Also, by configuring the video disc player, it is possible to project the copy point on the surface of the disc and to project the carrier copy to the photosensitive detector and to detect the carrier copy from the surface of the disc, as the rotating disc rotates with respect to the reader. It is also an object of the present invention to identify an apparatus and method for enabling the continuous control of light rays on an information track of a video disc.

It is still another object of the present invention to develop a video disc reading device so that the fluid bearing adjuster is configured to adjust a variable bias force on the read head facing the disc so that the gap between the read head and the disc is made constant regardless of the head radial position. In addition, information tracks formed on discs are identified by generating differential error tracking signals that identify the position of the colliding beams relative to the center of the information track and generate a control signal to move the reading beam speed toward the center of the information track. It is also an object of the present invention to provide an apparatus and method for enabling effective radial tracing of the present invention.

In addition to the apparatus and method for radially tracking the information track formed on the video disc by responding to the position of the reading line incident to the peripheral part of the information track, the phase difference between the signal recovered from the information track and the reference signal It is also an object of the present invention to provide an apparatus and method for tangentially tracking an information track formed on a video disc by detecting a.

Finally, an object of the present invention that can be presented is a video disc player having a fusiform servo system capable of controlling the speed at which the player rotates the disc element with respect to the read light flux, and an information track of the read flux and the video disc element. It is in developing a video disc player with a carriage servo system that can move relative to each other.

As described above, the objects and features of the present invention will be described in detail with reference to the accompanying drawings.

The video disc player system 1 illustrated in FIG. 1 is an apparatus capable of optically reading information recorded on the surface of a video disc element, in which an optical system 2 is constructed, which is further illustrated in FIG. 2a. Is illustrated.

Referring to FIG. 2A, there is an optical system 2, which is a read laser 3 which generates a read flux 4 which can read an encoded signal of frequency modulation accumulated in the video disc 5; have. The reading flux 4 is polarized in a predetermined direction and travels toward the video disk 5 by the optical system 2.

An additional function of the optical system 2 is to project an image of the light beam at a point 6 at the point of impact on the video disk 5.

2B shows an enlarged portion of the information recording surface 7 of the video disc 5, each of which is generally indicated by a line 9. This line 9 is indicated in the drawing in which a plurality of specular light reflecting elements 10 and heavy light reflecting elements 11 are arranged in succession.

An example of heavy light reflection is light scattering of the same type that appears when a focused beam of light 4 collides with a dish-like element 11 formed on a disk 5 that is rotating on the highway.

The direction of rotation of the disk 5 under the stationary read point 6 is indicated by the head above the arrow 12.

The reading flux 4 has two degrees of movement, the first of which is indicated by the arrow 13 in the radial direction and the second of which is indicated by the arrow 14 in the tangential direction. The arrow head direction of each arrow 13, 14 indicates that the reading point 6 can move in the radial and tangential direction.

The optical system 2 is constituted by a lens 15 used to form a line speed 4 capable of sufficiently capturing the inlet 16 of the microscope objective lens 17.

The objective lens is used to form the light spot 6 at the collision point of the ranges 10 and 11 in the information track 9. Filling the inlet 16 with the reading flux 4 results in much better results because the luminous intensity at the light spot 6 is maximized.

After the beam 4 is properly formed in the lens 5, it passes through the beam splitting prism 20.

The axis of the prism 20 causes some residual deviation from the path of the flux 4, for the purpose of influencing the operation of the optical system 2 when the prism is related to the reflected flux 4 '.

The transmitted portion of the flux (4) from the prism (20) passes through a quarterwave plate (22), which is circular to the incident light forming the flux (4). Impart polarization of.

The read flux 4 then impinges on the fixed mirror 24 and the mirror 24 directs the read flux 4 again to the primary pedestrian mirror 26 and the secondary mirror 28.

The function of the secondary Confucian mirror 28 is to move the beam of light in a tangential first motion to the surface 7 of the video disk 5 so that the read flux (4) due to the eccentricity formed at the time of manufacturing the disk 5 This is to correct the timebase error introduced in. The tangential direction is the front-rear direction along the information track 9 of the video disc 5, as indicated by arrow 14.

The primary Confucian mirror 26 directs the beam of light to the secondary Confucian mirror 28. The primary Confucian mirror 26 is used as a radial tracking mirror. The function of the tracking mirror 26 allows a single information track by controlling the collision point 6 of the reading flux 4 in response to a complex tracking error signal by slightly changing the physical position relative to the reading flux 4. According to (9), the information elements 10 and 11 are radially tracked.

The primary Confucian mirror 26 is in a one-degree movement, thus moving the beam of rays in a radial direction on the disk 5 surface in the direction indicated by the arrow 13. In this case, as described above, the reading flux 4 collides with the inlet 16 and focuses on the point 17 on the information track 9 of the video disk 5 with the lens 17.

The information track 9 is circular in shape or threaded.

The surface 7 is covered with a highly reflective film which results in greater mirror and antireflection, respectively, in the ranges 10 and 11.

In other words, the player 1 is an apparatus for optically reading information recorded on the surface of the video disk 5, which generates a radiation reading flux 4 impinging on the surface 7 of the disk 5; There is a light source.

The optical system 2 is used to straighten the read flux from the light source 3 to the disk surface 7 along a constant optical path. A pair of mirrors 26, 28 form part of this optical path, with the mirror 26 positioned opposite to the mirror 28 so that the read flux 4 is at least 1 in each mirror 26, 28. To reflect light. At least one of the mirrors 26 and 28 is made flexible so as to precisely adjust the read flux on the surface of the disk 5.

In the normal method of operation, the focused beam of light 4 impinges on the continuously arranged mirror light reflecting range 10 and the heavy light reflecting element 11 to display the dominant wave modulation information. The heavy reflective element 11 is a light scattering element possessed by the video disk 5. The reflected light beam 4 'is light that is a modulated light beam and corresponds to a frequency modulated signal represented by mirror light reflection and heavy light reflection elements 10 and 11 formed on the track 9.

When the modulated light beam is reflected from the elements 10, 11 continuously formed on the video disk 5, it is focused using the microscope objective lens 17.

The reflected read flux 4 'is projected along the same path as in the case of collided read flux 4. This path is continuously reflected through the secondary pedestrian mirror 28, the secondary pedestrian mirror 26, and the fixed mirror 24. The common path formed in the read optical system 2 uses two types of the incident light beam 4 and the reflected light flux 4 '. When the reading flux 4 'is reflected, it passes through the quarter wave plate 22, which changes the circularly polarized reading flux into a linear flux with a total polarization of 90 °.

Reflected reading flux 4 'coming from wave plate 22 in the opposite direction of reading flux 4 passes through beam split prism 20, which has a phase shift of 90 [deg.]. The reflected read flux 4 'is classified and diverged so as to collide with the tracking error signal recovery circuit 30. The prism 20 optically separates the reflected beam 4 'from the read flux 4.

The circuit 30 generates a radial tracking error signal.

One function of the flux splitting prism is to prevent all of the reflected reading flux 4 'from being fed back into the laser 3. Returning the reading flux 4 'back to the laser 3 disrupts the mechanism by which the laser operates in a constant operating manner, so the beam split prism 20 causes the laser to return to the reflected reading flux 4' Redirect most of the reflected read flux (4 ') to prevent feedback from being affected by (3).

In the case of a solid state laser, it is hardly affected by the feedback of the reflected light beam 4 ', in which case the beam splitting prism 20 does not need to be used. The solid state laser 3 serves as a light detector of a signal recovery sub-system.

In the video disc player 1 illustrated in FIG. 1, the normal operation of the signal recovery subsystem 30 is to send a plurality of signals to the residual circuits forming part of the player 1.

The primary one of these signals is an information signal representing accumulated information. The secondary one is a control signal derived from the information signal for controlling the Confucian mirrors 26 and 28. The information signal is a frequency modulated signal representing information accumulated in the video disk 5.

This information signal is sent on the line 34 to the frequency modulation processing system indicated by (32). The focus servo subsystem is illustrated at 36 and the mirror control signal generated by the signal recovery subsystem 30 is applied to the mirror control subsystem as illustrated at 40 on lines 41 and 42. This is a control signal.

When the player 1 is operated, the primary function of the video disc player 1 is to operate the laser 3 (FIG. 2) and the spindle motor 48 to operate the collectively installed spindle. (49) and the video disk element (5) installed therein are rotated.

The rotational speed of the spindle 49 in the spindle motor 48 is controlled by the spindle type servo system 50.

A spindle tachometer (not illustrated) is provided with respect to the spindle 49 to generate an electrical signal indicative of the current rotational speed of the spindle 49. The tachometer consists of two pick-up elements, which are installed at an angle of 180 ° with respect to the spindle 49.

Each tachometer generates an output pulse. They are installed with a weft of 180 ° for each, eliminating the drawbacks in installing the tachometer wheels.

The line 51 has a continuous pulse generated by the primary tachometer connected to the spindle type servo subsystem 50, and the line 52 has a secondary tachometer connected to the spindle type servo subsystem 50 It has a tachometer pulse.

The spindle type servo system 50 has a constant rotational speed, ie 1799. 1 r. p. When the m. is reached, a line 54 generates a player operation signal.

When the rotation speed is exactly 1799.1, the TV information screen will appear on the standard TV set.

The secondary function of the video disc player 1 is to operate the carriage servo subsystem. As described above, in order to read the frequency-modulated encoded information from the video disk 5, a collision is caused by focusing the read flux 4 at the light reflection range 10 and the light reflection range 11 of the video disc 5. Just do it.

In order to obtain the proper result, the read flux (4) must impinge at right angles to the plane with the encoded information. In order to establish such a geometric position, it is necessary to provide relative anisotropy between the connected optical system 2 and the video disk 5.

Either the video disk 5 moves under a fixed laser readout flux 4 or the optical system 2 can move relative to the fixed video disk 5.

To do this, the optical system 2 is fixed and the video disk 5 is moved under the reading flux 4.

The carriage servo subsystem controls the relative movement between the video disk 5 and the optical system 2.

The carriage servo subsystem 55 provides 1 ° flexibility to the overall function of the video disc player 1 by instructing relative anomalies in various different modes of operation as described above.

In the primary mode of operation, the carriage servo subsystem 55 moves the carriage device 56 perpendicular to the information recording surface of the video disc 5 in response to player actuation signals applied to the player on the line 54. The reading fluxes 4 collide in the direction.

At the same time, it is important to use a carriage device to identify the structural elements on the video disk.

It also consists of a spindle motor 48, a spindle 49, a spindle tachometer (not illustrated in the figure), a carriage motor 57 and a carriage tachometer drive 58.

The carriage device has not been specifically illustrated in order to avoid the complexity of the group diagram illustrated in FIG. A summary of the video disc's operation is that the carriage servo subsystem's ability to move the carriage to its initial position at the beginning of the rest of the player's functions continues.

The carriage motor 57 generates a driving force for moving the carriage device 56.

The carriage tachometer drive device 58 is a power source that generates a current that indicates the moving direction and the instantaneous speed of the carriage device.

When the spindle type servo system makes the spindle speed up to the operating speed of 1799. 1 rpm, a player operating signal is displayed on the line 54 to control the relative movement between the carriage device 56 and the optical system 2. It is delivered to the carriage servo subsystem.

After operation, the focus servo subsystem 36 controls the lens 7 to act on the video disk 5. The focus sub system is illustrated specifically in FIG. 7. This focused servo 36 is used to apply various outputs to the readhead in the normal direction of the disk 5 to maintain a constant distance between the readhead and the disk 5 regardless of the radial position of the head. do.

The function of the focus servo subsystem 36 is to maintain the distance between the lens 7 and the video disk 5 properly so that the light reflecting range 10 and the light reflecting range which are continuously reflected from the video disk 5 are installed. Allow the lens 17 to connect the maximum amount of light modulated at 11.

The tangential servo subsystem 60 receives the primary pressure signal from the frequency modulation processing system 32 on the line 62.

The input signal on the line 62 is a frequency modulated signal detected by the lens 17 from the surface of the video disk 5 and amplified by the signal recovery sub-system 30 by the line 34 to generate a frequency modulation processing system ( 32).

The function of the tangential time base error correction subsystem 60 is to adjust the signal detected from the video disc 5, i.e. the tangential error caused by the eccentricity of the information track 9 on the disc 5 And other errors introduced in the detected signals due to the physical defects of the video disc 5 and mechanical errors in the player.

The tangential time axis error correction subsystem 60 also has the function of comparing the signal read out from the disk 5 with the locally generated signal.

The difference between these two signals represents an instantaneous error in the signal read by the player 1. In particular, the signal read out from the disk 5 is a signal that is carefully applied to the disk with a phase to other recorded signals.

The frequency modulated signal of the color TV is the color divider part of the video signal.

The locally generated signal is a crystal controlled oscillator operating at 3.579545 MHz of color subcarriers.

The tangential time axis error correction sub-system 60 detects the phase difference between the color branch signal and the color carrier oscillation frequency and then adjusts the phase of the residual part of the frequency modulation information series included in the color branch signal.

The phase difference for each series is generated according to a method of continuously tangential time axis error correction of a signal read from the disk.

In an accumulation information signal having no part where the color-branching signal can be compared, a signal having a phase with respect to the residual signal of the disk 5 can be periodically added to the information when recording on the disk 5. In operation, the recorded information is selected and compared with a locally generated signal that can be compared with a color carrier oscillator.

In this way, the received time-base error correction can be performed on the signal recorded in the video disk element.

When comparing the signal read out from the video disk 5 with the frequency of the color carrier carrier oscillator generated internally, the detected error signal is sent to the secondary Confucian mirror 28 on the lines 78 and 80.

The signals on lines 78 and 80 are actuated to move the secondary Confucian mirror 28 so as to go straight back and forth to the reading flux 14 along the information track in the direction of the arrow 14 to produce the video disc 5 or It is necessary to correct the injected time axis error due to the defect that appears during reading.

Another output signal from the tangential sub-system is the motor reference frequency applied to the fuzzy servo bushing system 50 on line 72. It is convenient that the motor reference frequency is generated in the tangential sub-system 60 because the frequency of the color carrier carrier oscillator used in the comparison operation as described above exists. The frequency of the color carrier oscillator is a signal that is accurately generated. It is separated by the motor reference frequency used to control the fuzzy servo speed. As the frequency for controlling the speed of the spindle is effectively limited to the color carrier frequency, the spindle is rotated in the correct image frequency range necessary to show the maximum display fidelity of the information detected from the video disk 5 of the TV receiver 76.

The output signal from the radial tracking mirror control subsystem 40 includes a primary radial mirror tracking signal generated at line 68 and a secondary radial mirror control signal generated at line 70. Mirror control signals on lines 68 and 70 all enter primary pedestrian mirrors 26, which are used for radial tracking purposes.

The control signal on lines 68 and 70 moves the primary Confucian mirror 26 so that the reading fluxes 4 impinging on it move in the radial direction so that the information tracks are illuminated by the focused light spot 6. (9) will be centered.

The output from the spindle type servo subsystem 50 is directed to a spindle type motor 48 on line 82.

The output generated from the carriage servo 55 driving the carriage motor 57 is sent directly to the line 84.

The current generated by the carriage tachometer drive device 58 applied to the carriage servo subsystem 55 is sent to the carriage servo subsystem 55 on the line 86 as indicating the direction and instantaneous speed of the carriage.

The primary output signal from the frequency modulation processor 32 enters the audio processing subsystem 88 on line 90. The signal of the line 90 is a frequency modulated video signal from the frequency modulation processor 32.

In addition, the output signal additionally generated from the frequency modulation processing subsystem 32 enters the radio frequency modulator on the line 94. Line 94 has a video output signal generated from the frequency modulation detector portion of frequency modulation processor 32.

The audio processing system 88 supplies an output signal that is applied to the radio frequency modulator 92 on the line 96.

The signal applied to the radio frequency modulator 92 on the line 96 is a 4.5 MHz carrier frequency modulated by the audio information, which is also a channel having a center frequency selected for use as one channel of the TV receiver. Modulate the frequency oscillator. This modulated channel frequency oscillator enters the standard TV receiver 96, and the internal circuitry of the TV receiver demodulates the audio contained in the channel frequency signal modulated in the secondary operation.

The output of the audio processing system 88 modulates a 3/4 channel frequency oscillator before being applied to the TV receiver 76 of the standard specification. Meanwhile, after selecting 3/4 channel for this purpose, the vibration frequency of the channel frequency oscillator is used for the channel of the TV receiver 76. The output of the radio frequency modulator 92 is fed to a TV receiver 96 on the line 98.

The optical system 2 illustrated in FIG. 3 is mounted on a movable arm 100, which also has a readhead 102. The arm 100 is supported as a rotating element 104 which moves the readhead 102 in the radial direction with respect to the disc 7. The turn table 106 supports the disk 5.

In operation, the laser 3 causes the reading light beam 4 to enter the surface 7 of the disk 5 straight through the optical system 2. The information recorded on the disk interacts with the incident light flux and generates a reflected light flux containing the recorded information. The reflected light flux is conveyed to the signal recovery circuit 30 through the optical system 2. The circuit 30 analyzes the information of the reflected light flux 4 so that the light flux 4 properly tracks the information track 9, It is determined whether there is.

If it is determined that the laser light spot 6 does not go directly to the predetermined portion of the information channel 9, when applied to the readhead 34, it will induce an appropriate servo signal to radiate or tangentially collide the collision point of the laser beam 4. Direction so as to be aligned with the track 9 to be read.

As another method, the drive of the rotating element 104 relative to the reproducing apparatus 1 is controlled by a servo signal to move the position of the laser light spot 6. In another method, the motor is connected to the turntable so that the radial motion increases at a constant speed with each turn of the turntable 106.

In either case, the reproduction head 102 tracks the information channel recorded on the disc 5 while making coarse adjustments to the drive mechanism of the rotating element 104 and making fine adjustments to the Confucian mirror. That is, the cam and the cam ball 108 (which will be described in detail with respect to FIG. 7) are installed on the rotating element 104 to be in contact with the arm 100 via the flexible cable 110.

As illustrated in FIG. 4, the laser 3 is used as a light source for generating a read flux for light radiation. The optical circuit 2 is used as a beam flux linear circuit to optically advance the read flux from the laser 3 to the information track 9 along the flux path 4. The flux path 4 consists of the primary part 4a to which the reading flux 4 moves.

The secondary portion 4b is a portion through which the incident read line flux passes through the disk 5 and the reflected read line flux passes from the disk 5 to the flux directing circuit 111. The reflection beam 4 'from the common path portion 4b is allowed to proceed to the tertiary portion 4c.

The tertiary portion 4c extends from the prism 20 to the photosensitive element 112 that senses the reflected flux 4 '.

When the reading flux 4 collides with the information track 9, the flux 4 is modulated by the information displays 10 and 11.

The reflected modulated flux 4 'will at least retrace the portion 4b of the read path 4.

The beam splitting circuit 111 includes a beam splitting prism 20 and a quarter wave plate 22 disposed between the prism 20 and the disk 5. The path 4 is formed as an optical circuit 2 along the folded U-shaped optical path and connected to the disk 5. The common path portion 4b forms at least part of the U-shaped path.

3 and 4, the path 4 is formed along the primary and tertiary path portions parallel to the disk surface of the optical circuit 2. The secondary path part connects the primary path and the tertiary path. The fourth path portion connects the information track (9) with the other end of the third path portion.

The other end of the primary path portion is connected with the laser light source 3. Therefore, it can be seen that the primary path portion is parallel to the tertiary path portion, the fourth path portion is perpendicular to the tertiary path and primary path portion, and is also perpendicular to the disk surface 7.

As can be seen in FIG. 2, the fourth path portion starts from a fixed mirror 24 and has movable mirrors 26 and 28 and a lens 17. The primary moving mirror 26 is used to change the path of the reading flux 4 to the track 6 with the disc surface 7 so that the reading flux 4 is tangential along the information track 9. To be moved.

The lens is an objective lens for a microscope. The lens 17 is mounted on the readhead 102 to be adjusted along the fourth path portion, thereby adjusting the focus of the reading flux 4 at a portion of the information track 9. In addition, the reflective flux passes through the common path portion 4b to the sensing circuit 112.

Fixed mirrors 114 and 116 are used to allow the flux portion 4a to advance to the lens 15.

The readhead 102, illustrated specifically in FIG. 4, has a fluid bearing element 118, which is adjacent to support the microscope objective lens 17. 4 also illustrates a movable radial tracking mirror 28 that is coupled to a secondary fixed mirror 120 and a tertiary fixed mirror 24. At least one flux is reflected from the Confucian mirror 28 before the read flux 4 enters the objective lens 17.

4 illustrates the reflection of the ship speed twice. Similarly the primary fixed mirror 24 leading to the photosensitive element 112 as representing the path of the beam reflected from the radial tracer mirror 28 by the reflected beam 4 ′ conveyed from the surface 7 of the disk 5. It illustrates that the reflection from the fixed mirror 120 twice before entering the optical path (4 ') comprising a.

Confucian mirror 28 is installed on the center point 22 to be positioned at the center with respect to the mirror 28.

The mirror 28 has a long oval shape having a long side in the plane of the drawing and a short axis orthogonal to the plane of the drawing. A mirror drive device 124 is provided at one end of the mirror 28 to allow movement around the center point 122 which moves the ship speed 4 in the tangential direction as shown by the arrow 14 illustrated in FIG.

If the drive device 124 rotates the mirror 28 clockwise as illustrated in FIG. 4, the impulse point of the read flux 4 moves upwards. This indicates that the line speed is deflected along the arrow 14 in the first tangential direction. If the drive 124 rotates the mirror 28 in the counterclockwise direction, the collision point of the transmitted ship speed 4 moves downward as shown in FIG. 2B or along the arrow 14 to the secondary. It moves in the opposite tangential direction.

The refracted flux 4 'and the incident reading flux 4 travel along the same path between the surface 7 of the disk 5 and the flux splitter 20. The mirror 28 serves to read only the illuminated portion by adjusting the reading point to the desired position. The modulated readout flux 4 is refracted back to the signal recovery device 30.

In addition, by adjusting the mirror 28 and the stationary mirror 42 again, the position is re-adjusted, and a plurality of mirrors between each of the two mirrors 28 and 120 before the swift 4 enters or exits the disc surface 7. Will be reflected. This arrangement can further reduce the size of the mirror refraction needed to properly adjust the reading point. Therefore, the drive device 124 may be moved only slightly to the Confucian mirror 28.

As shown in FIG. 2a, the secondary guiding mirror 28 is mounted on the center point element 122 to drive around the axis orthogonal to the plane of FIG. 2a, and the mirror 28 and the primary drive at the end of the long axis. 124 is combined to allow rotation clockwise and clockwise.

The secondary drive 126 is connected to one end of the primary mirror 26 to cause the mirror 26 to rotate about the long axis 128 in the plane of FIG. 2.

In actual operation, the secondary drive device 126 drives the read flux 4 in a radial direction to enable fine tracking of the information channel.

The primary drive unit 124 is used to move the ship speed in the circumferential direction along the direction indicated by the arrow 14 in Fig. 2b, so that the tangential direction can be tracked, thereby improving time synchronization and compensating eccentricity. Make this possible.

Mirrors can be used in many different ways for different purposes. In the use of the fixed mirror 120 in combination with the Confucian mirror 28, only when the radial adjustment is necessary.

Selective control of the mirror 28 allows the read line flux 4 to be adjusted to the correct position on the surface 7 of the disc 5.

In the use of the primary Confucian mirror (26) in combination with the secondary Confucian mirror (28) is used when both radial control and tangential control are required.

In the arrangement as described above, each mirror is positioned opposite to each other. In the primary arrangement, the mirror pairs 26, 28 and 120, 28 are arranged such that each of the incident light beam 4 and the reflected light beam 4 'is reflected once from each mirror in the incident light path and the reflected light path. .

In the secondary arrangement, the mirror pairs 26, 28 and 128, 28 are arranged so that a plurality of reflections occur on the incident path to the reading flux 4 and the reflection path to the flux 4 '.

Each of the mirrors 26, 28, and 120 has a reflecting plane which, when combined, is present in a plane parallel to the plane in the other plane of the combined secondary mirror in the case of the combination.

In the separate arrangement illustrated in FIG. 10, the reflection plane is present at the converging plane for each coupled mirror. The convergence angle between the reflecting surfaces is such that the read line flux 4 reflects a plurality of reflections in the direction opposite to the convergence direction and then reflects the plurality of reflections in the convergence direction.

Referring to FIG. 5, there is a radial mirror control device 40 where the reflected flux 4 'impinges on the photosensitive element 112.

When the information track 9 is appropriately tracked at the external intermediate point 6 of the information track 9, an output signal of a certain magnitude is generated. The output of the photosensitive element 112 is supplied to the addition operation element 130 on the line 132.

Also, an adjustable bias signal is supplied from the bias source 134 on the line 136 to the other input of the add operation element 130.

The bias source 134 is adjusted to provide a zero output signal when the output signal of line 132 is at a constant maximum level.

The error signal output from the addition operation element 130 on the line 138 is sent to the phase and amplitude compensation element 140, and the compensated output is supplied to the radial tracking mirror driving device 124 to adjust the line speed 4 Track 9 is tracked.

However, if the track 99 is not properly tracked, a state develops in which the energy impinging on the photosensitive element 112 is different from the bias supplied by the bias circuit 134. Therefore, by correcting the position of the light spot 6 with respect to the information track 9 by sending an error signal for the appropriate polarity, the output of the compensation element 140 is supplied to the mirror drive device 124, if the bias signal If is large, the function is exerted to move the light spot toward the periphery of the disk.

If the received signal is large, the light spot is moved to the center of the disk. If the light spot 6 tracks the threaded track 9 properly, the differential output will be zero. For example, the drive unit 124 causes the ship 4 to exit in the radial direction at a constant speed. The output of the compensator 140 corrects the speed moving to the center of the ship speed 4 by supplying a correction signal. If the bias signal becomes large and moves the light spot 6 toward the center of the disk 5, the light spot 6 will track the track at its inner circumference.

On the other hand, when a large bias signal moves light spot 6 to the periphery, light spot 6 tracks the outer periphery of track 9. In either case, correcting the error signal imparts an appropriate function to the drive device 48 to track the track 9 in general.

Radial tracking circuits associated with FIGS. 5 and 9 include electrical circuit elements responsive to the position of the colliding beams relative to a constant periphery of the information track 9 so that the primary polarity will not occur if the beams do not impinge on the aforementioned constant perimeters. If we collide with a lot more at a certain periphery, we generate an electrical output variable with secondary polarity.

The circuit element described above includes an add operation amplifier and a bias source. The addition element has a pair of inputs and one output. The output of the bias source is used as one of the inputs of the add operation elements. The photosensitive element is used as the secondary pressure of the additive operation element to which the reflected flux 4 'travels. The output of the additive operation element represents the difference between the input from the photosensitive element and the input from the bias source.

The photosensitive element supplies a voltage output proportional to the light received from the information track 9 '. The bias source is an adjustable bias voltage source. The output from the additive operation element is a voltage proportional to the difference between the photosensitive element and each output from the bias source.

When the bias circle is adjusted when the reflected light beam 4 'impinges on a constant periphery, and becomes zero, the known amount of reflected light 4' is detected by the photosensitive element.

The output of the additive operation element is supplied to the compensator circuit to generate an output signal to the radial drive device 48 that controls the tracking mirror 28 to enable relative radial movement of the light spot 6 on the information track 9.

FIG. 6a is a generalization of the collective diagram of the spindle type sub subsystem 50. One of the functions of the subsystem 50 is that the spindle motor 48 has a constant rotational speed, that is, 1799. 1 r.pm. The rotation speed of 49 is maintained. Obviously this number was chosen to be bonded to the scan frequency of a standard TV set. A standard TV receiver receives 30 images per second and records the information on a video disc so that one complete image of the VT information contains one thread or track.

If the time demand of the TV set or TV monitor is different from this standard, the function of the fusible servo subsystem is to maintain the rotational speed in the new standard.

A start pulse activates the spindle motor 48. As the motor rotates, the input signal pulse train of the primary tachometer is applied by a schmidt trigger on the line 51. The input signal pulse train of the secondary tachometer is applied toward the secondary limit trigger 152 on the line 52.

A 9.33 KHz motor reference frequency is applied to the tertiary limit trigger 154 from the tangential servo subsystem 60 on line 72.

The output of the trigger trigger 150 is applied to the edge generator 160 and the output of the trigger trigger 154 is applied to the edge generator circuit 164.

Definition of the signal applied to each using each edge generator (156, 160, 154). It generates a pulse corresponding to the sub-directed edge.

Using the output of the edge generator 154 as a reference phase signal, the primary phase and frequency detectors operate to show the phase or frequency difference between the input signal and the motor reference frequency in the rotational speed. In addition to the phase and frequency detector 167, it is also applied to the secondary phase detector 168. Phase detector 167 has an output coming from edge generator 156 as a secondary input signal. Phase and frequency detector 168 has the output of edge generator 160 as an error input signal. The output of phase and frequency detector 167 is sent to add operation circuit 169 and the output of phase and frequency detector 168 is also applied as a secondary input to add operation circuit 169.

The output of the addition operation circuit 169 is applied to the lock detector 170 and the power amplifier 171.

The function of the lock detector 170 is to indicate the time when the speed of the spindle reaches a constant rotational speed, which is possible by sensing the output signal of the addition operation circuit 169.

The rotational speed of the spindle motor must reach a predetermined speed before the carriage unit can operate.

When the video disk reaches a relatively high rotational speed, the disk is placed in an air cushion and rises slightly perpendicular to gravity.

Therefore, the centrifugal force of the video discs makes the video discs somewhat flat. The vertical movement against gravity caused by the disc in the air cushion and the vertical synergy caused by the centrifugal force both move the video disc from its original position to a stable position, with the internally fixed guitar in the video disc player box It will be in the intended position with respect to the element. By calculating the dynamics of a rotating disk rotating at 1799.1 rpm with a constant weight and specific gravity, it is necessary to confirm that the disk maintains a constant distance to all internal elements and does not make any unnecessary contact. Contact between the disc and the player vehicle causes friction and damages the video disc.

The lock detector 170 is installed to become a phase lock so that the player operating pulse is generated on the line 54 when the spindle speed is completely 1799.rpm.

While the video disc player 1 is operating normally, the input signal of the tachometer is continuously applied to the shim triggers 150, 152 on the lines 51, 52, respectively. The input signals of these actual tachometers are compared with the motor reference signal on the line 72 to detect whether there is a deviation in the computation addition circuit 169 applied to the power amplifier 171. The power amplifier 171 applies a driving force to the spindle motor 48 so that the rotational speed of the spindle 49 on the line 82 maintains the required speed.

The primary input signal in the tangential servo subsystem 60 illustrated in FIG. 6B is applied from the frequency modulation processor 32 on the line 62. The signal on line 62 is the video signal from the video distribution amplifier in frequency modulation processing system 32.

The video signal on line 62 is sent to color separation filter 173 on line 174 and the video signal on line 62 is also sent to branch gate generator circuit 175 on line 176.

The function of the color separation filter 173 is to separate the color portion from all the video signals received from the frequency modulation processing circuit 32. The output signal of the color separation filter 173 is applied to the phase detector circuit 177 on the line 178, which has a secondary pressure signal generated from the color subcarrier oscillator circuit 179 on the line 180. . The purpose of the phase detector circuit 177 is to compare the instantaneous phase of the color signal with the signal of the color subcarrier oscillator generated extremely accurately at the vibrator 179. The phase difference detected by the phase detection circuit 177 is output to the specimen support circuit 181 on the line 182. The function of the circuit 181 is to provide a full line of video information used to generate a phase difference including a color signal. It is to accumulate a voltage corresponding to the branch phase difference detected by the phase detector circuit 177 during the time when the line is read from the disk 5.

A branch gate generator 175 generates an operation signal indicating the time during which the color branch portion of the video waveform is received from the frequency modulation processor 32. When the output signal of the branch gate generator 175 is applied to the specimen support circuit 1 81 of the line 183, the actuating signal on the line 183 transmits the input from the phase detector 177 to the epoch in the chromatic part of the video signal. The gate is made into the support circuit 181.

The color carrier carrier oscillator circuit 179 sends the color carrier to the division circuit 184 on the line 185 and divides the frequency of the color carrier into 384 to generate a motor reference frequency. The motor reference frequency signal is sent to the spindle type servo system 50 on the line 172.

The output of the sample support circuit 181 is sent to the automatic gain control amplifier circuit 186 on the line 187.

The auto gain control amplifier 186 has a secondary input signal from a carriage position potentiometer. The function of the signal on line 188 is to change these of the amplifiers 186 as the reading line flux moves radially from the outer track to the inner track.

The necessity of adjusting the change due to the radial positional change is necessary to form the reflection range 10 and the sub-reflection range 11 having various different dimensions from the outer track to the inner track.

The spindle motor 48 is to maintain a constant rotation speed is to send 36 information images to the TV receiver 76 by rotating the disk to make almost 30 revolutions per second.

The track at the outermost periphery is much longer than the track at the innermost perimeter. Since the same amount of information should be accumulated in one rotation range at the inner and outer circumferences, the size of the reflection range 10 and the non-reflection range 11 is adjusted from the inner radius to the outer radius, respectively. Therefore, in making such a change in size, a certain amount of adjustment must be made as an appropriate operation when processing the detected signal read out from the video disk 5.

One such adjustment is to adjust the timebase error as the read point changes radially from the inside to the outer periphery by adjusting the gain of the amplifier 186. Carriage position potentiometers (not illustrated in the figure) generate sufficient accurate reference voltages indicating the radial position of the point of impact of read line flux 4 with respect to video disk 5. The output of amplifier 186 is sent to phase and amplitude correction circuit 188 on line 189. The correction circuit 188 is used to stabilize the servo system. The output of the correction circuit 188 is sent to the tangential mirror driving circuit 190 on the line 191, which is to be compared with the radial mirror driving circuit described above with respect to FIG. Circuit 190 consists of a pair of push-pull amplifiers (not illustrated) that direct the output of the amplifier to the tangential mirror 26 on line 68 and to a secondary push-pull. The output of the amplifier (not illustrated in the figure) is directed to the tangential mirror on line 70.

The frequency modulated video signal recovered from the surface of the video disk 5 is corrected for the time axis error introduced during the reading of the tangential servo subsystem 60.

The time base error is introduced in the reading process due to the inadequate defect of the video disc 5.

The time base error introduces a slight phase change in the recovered video signal. A typical timebase error correction system contains a highly precise oscillator that generates the signal used as the phase reference for the comparison process. Precision vibrators are designed to vibrate conveniently at the color carrier frequency. The output of the highly controlled oscillator is compared with the chrominance signal of the color video signal. In the reading process, this frequency is compared to the player's oscillator and senses the phase difference between the two signals.

The color splitter signal forms part of the recovered video signal. The color splitter signal is repeated in each of the color TV video information lines of the recovered video signal. The presence of phase error is detected by comparing each part of the color splitter signal with an accurate subcarrier oscillator.

In making these comparisons, random comparisons are made from time to time, rather than during the use of each color splitter signal. If the recorded information is not highly sensitive to phase error, the comparison is carried out with a larger scene interval. In general, the phase difference of the recovered signal is adjusted by repeatedly detecting the phase difference between the recorded signal and the locally generated signal at a predetermined interval on the surface to be recorded.

The repetitive detection of the phase difference is performed on each line of the video signal.

To detect the detected phase error for a certain time, the phase error is used to correct the phase error with respect to the collision point of the video disc by adjusting the reading position of the read line flux.

The incremental portion of the video signal recovered during the sampling period is adjusted by repeatedly comparing the recorded signal with the locally generated highly accurate frequency.

The phase error also changes with the radial tracking through the information recording surface of the read flux video disk 5. In order to adjust the phase error according to the instantaneous position of the information recording portion of the video disc 5, an additional signal is required to adjust the phase error based on the instantaneous position of the read line. This additional signal is due to the change in the physical size of the information display implied on the video disk as the radial tracking position changes from inside to outside. Compared to the information display in the outer radius, the marking should be smaller on the inner radius side.

외부 반경에서 동일할 경우 이러한 추가적인 신호는 순간적인 방사형 위치를 조정하는데 필요로 하지 않는다. 이러한 것은 정보를 비데오 디스크 요소와 동일 크기로 하여 디스크형 보다는 스트립(strip)형으로 비데오 디스크의 요소를 만들 경우에는 작동이 가능하다.The size of the display is my

These additional signals are not needed to adjust the momentary radial position if they are the same at the outer radius. This works if the information is made the same size as the video disk element and the video disk element is made in a strip rather than a disk type.

The tangential mirror 26 serves to correct the time axis error introduced by the mechanical action of the reading system.

These mirrors are electronically controlled and change the time base for reading signals from the disk.

Depending on the amount of phase error, the degree of position change is determined, and thus the time to read the information is also determined.

If no phase error is detected in the time-base correction system, the collision point of the reading flux to the surface of the video disk 5 is not moved. When the phase error is detected in the comparison process, it generates a signal to change the collision point, and is used to process the information recovered from the video disk before and after the comparison process. This may change the spatial position of the point where the surface of the video disk 5 and the reading line flux intersect.

The tangential servo circuit 60 is effective for correcting phase errors associated with time axis errors for the circular and threaded information tracks 9. The basic function of the tangential servo circuit 60 is to identify and detect the position at which the reading flux 4 collides with the surface 7 of the disk 5.

This function compensates for phase errors associated with time axis errors by operating against radial tracking errors to make circumferential adjustments at the position of the ship 4 to accurately relocate the ship 4 at the point of impact on the information track 9. Can be processed electronically. This circumferential adjustment can be made using a tangential mirror 26.

The electronic output of the tangential servo circuit 60 is an input to the tangential device that adjusts the collision read flux 4 circumferentially along the track 9 on the disc 5 and rotates the mirror 26. use.

6C shows the surface of the disk 5 and the readhead using a power source 200 in a carriage servo system suitable for directing the relative motion between the surface 7 of the disk 5 and the readhead 102. It generates a constant current necessary to control the relative movement between the 102 at a constant speed so that the focus is adjusted to continue to the center of the information track 9 of the disk on which the light spot 6 is rotating.

As described above, the information track 9 is a continuous thread type and the one illustrated in FIG. 1 uses the movable carriage 56 and the stationary laser 3. The distance between the centers of adjacent threads of an information track is typically 2 microns. Thus, sufficient current is generated by the power supply 200 to move the carriage device 56 two microns laterally in a time when the disk 5 is completely rotated. This power supply roughly controls the relative motion between the readhead 34 and the information track 9. To fine tune the carriage speed it is measured as a voltage valve from the tracking servo.

The output of the power supply 200 is sent to the addition operation circuit 202 on the line 204, and the output of this circuit 22 is sent to the power amplifier 206 on the line 208. The output from the power amplifier 206 is sent to a carriage motor 57 of a pair of wires 84 and the dashed line 212 between the carriage motor 57 and the carriage tachometer 58 is a mechanical connection of these devices. Indicates that it is The output from the carriage tachometer 58 is sent to the addition calculation circuit 202 by a line 86.

When a start signal is sent to the power source 202 on the line 214, the power source 202 flows a constant current to move the carriage device 56 from the initial position to the starting point for the track position. As described above, the carriage device 56 and the optical system 2 are moved relative to each other. In moving the optical system 2 and the carriage device 56 in the standard operating mode, the reading fluxes 4 from the laser 3 collide with the recorded information starting point. Therefore, the power supply 200 generates a current applied to the addition operation circuit 202. The function of the addition operation circuit 202 senses the amplitude of the current generated by the power supply 200 and the amplitude of the current supplied from the carriage tachometer system 58 on the line 86 to the addition calculation circuit 202. To compare.

As described above, the current generated in the carriage tachometer 58 represents the instantaneous speed of the carriage device 56. This current on the line 86 and the current of the power supply 200 are compared to the power amplifier 206 on the line 208 which generates the power required to move the carriage motor 57 to the desired position. send. This power supply 200 generates a positive bias current capable of sufficiently moving the carriage device 56 at a distance of 2.0 microns each time the disk is rotated. In addition to this bias current, a current that can be finely adjusted from the tracking servo is added to the addition operation circuit 202 to give a constant current input signal to the power amplifier to move the carriage motor 57 at a constant distance every time. Let it be.

This positive input bias current from the power supply 200 is identified as the primary fixed bias control signal for the carriage motor 57.

In operation, the carriage servo system acts as a device that reads the readhead 102 to the disk 5, which readout becomes constant when using a threaded information track. When forming the information track 9 using multiple concentric circles, the readout circuit allows a constant incremental movement between the readhead 102 and the surface 7 of the disc 5.

The carriage servo system is to roughly control the relative movement between the readhead 102 and the disc 5, if both the readhead 102 and the optical system 5 remain the arms 102, this is the read flux (4). ) Shows the result of roughly adjusting the disk 5. Line speed 4 with respect to disc 5 by adjusting the path of line speed 4 with respect to readhead 102 using radial mirror stir servo 40, radial tracking mirror 28 and drive 124. You can make fine adjustments.

In the signal recovery subsystem 30 illustrated in FIG. 9, this is a secondary example showing the radial mirror control circuit 40. Reflected light beam 4 ′ impinges on photosensitive element 112, which includes portions 216 and 218 and directs the output of photosensitive element 216 to a primary tracking preamplifier on line 222. Sent to 220. The output of the secondary tracking photosensitive element 218 is sent to a secondary tracking preamplifier on line 2 26 and the output of the primary photosensitive element 216 is also sent to the addition operation arc path 228 on lines 22 2, 230. The output of the secondary photosensitive element 218 is sent to the addition operation circuit 228 on line 226 and secondary line 232.

The output of the primary tracking preamplifier 220 is applied as the input of the differential amplifier 234 on the line 112 and the output of the secondary tracking preamplifier 224 is also applied to the differential amplifier 234 on the line 238. Applied as difference input signal. Push-pull radial tracking applied to mirror drive 126 by sending output signal from amplifier 234 on front 240 and line 242 to phase- and amplitude-corrector and then to push-pull amplifier circuit 244 Generate an error voltage.

The output of the addition operation circuit 228 is amplified by the wideband amplifier 246 before being applied to the frequency modulation processing circuit 32 on the line 34.

In the radial tracking circuit illustrated in connection with FIG. 5 and FIG. 9, the information track 9 in FIG. 2B is constituted by a simple threaded information track. Due to the relatively small size of the information displays 10 and 11, the portion of the information track 9 illustrated in FIG. 2B is linear rather than circular. Each track 9 in FIG. 2b is a respective loop formed in a threaded track.

Another track forming method is to form a plurality of concentric circles, in which a movable mirror 28 is arranged to adjust the read flux 4 between adjacent circles.

Mirror components 120, 28 or 26, 28 are used to adjust the read flux 4 radially through the surface 7 of the disk 5, respectively. The position of the light spot 6 relative to the information track 9 is as shown in FIG. 2B. That is, in FIG. 2B, the light spot 6 is positioned at one point on the track 9 as the disk 5 moves in the direction of the arrow 12. The radial tracking circuit 40 illustrated in FIG. 5 maintains the light spot 6 on one side of the track 9. The radial tracking circuit 40 of FIG. 10 allows the light spot 6 to be maintained at the center of the track, with the radial direction indicated by the arrow 13.

The radial tracking circuit is designed to maintain the focus of the light spot on the crack 9 by detecting the position of the read flux 4 relative to the surface of the disk 5 with respect to the track 9.

When the light spot 6 moves in the track 9 'or (9 ″) direction, the error tracking signals 68, 70 selectively control the movement of the mirror 28 so that the beam speed 4 causes the disk 5 to move. Return to the selected track 9 for radial adjustment.

The radial servo circuits illustrated in FIGS. 5 and 9 detect the position of the beam 4 when the reading flux 4 collides with the surface 7 of the disk 5 to selectively select the pedestrian mirror 26. By generating an error tracking signal that enters the mirror 26 by the drive device 126 to control the control unit 126, the ship speed 4 is radially adjusted to the selected track of the disk 5.

In FIG. 8, the lens and the air bearing device 255 are enlarged, and the reproducing device 102 is included.

The air bearing device 255 has a function as a path control element of the lens 17, that is, the relative position of the lens 17 by focusing the line speed 4 as the light spot 9 on the information track 9. To adjust.

The device 255 also focuses the reflected light flux 4 'by adjusting the relative position of the lens 17, and also passes the reflected light 4' along the common path portion 4b to the sensing element 112. Let's do it. The reproduction head 102 is a primary vertical element 256 having a horizontal element 257 at one end.

The horizontal element 258 moves the lens 17.

The secondary vertical arm 258 is secured to the arm 100 using a bracket 259. The elements 258 of the arm 100 are connected to the elements 256 of the playhead 102 via a pair of parallel leaf springs 260, 262. The spring force of the leaf springs 260 and 262 must be sufficient to keep the spring in a horizontal position with the regeneration head 102 not supported by the fluid bearings coming from the rotating disk 7. Included as part of the readhead 102 are the fluid bearing element 118 and the microscopic objective lens 17. The fixed Confucian mirrors 26, 120, 28 are used to straighten the beam of light from the light source 3 onto the disk 5 via the lens 17 and as a arm 100 with respect to the inlet 16 of the lens 17. Stop at the contact. The support element 264 extends towards the readhead 102 towards the inner end of the arm 100.

A bias spring 266 is installed in this support element 264, which secures one end of the spring to the lever 268 as shown in FIG. The lever 268 is connected to the arm 100 via a flexible cable 110 and a cam and a cam ball connect the device 104.

Likewise included here is an interlock solenoid device, which is used when the arm 100 is separated from the disk 5 by using the cam and the cam ball properly connected to the disk 5 and the read head 102. This prevents contact and prevents damage to the disk 5 during tracking of the readhead 102.

The bias spring 266 acts to cause the lever 268 to move the readhead 102 upwards and away from the disc 5. Alternatively, the lever 268 rotates in the opposite direction while relieving the pressure of the spring 266 when the readhead 102 is positioned over the disc.

Under normal conditions, the weight of the readhead 102 is supported by the fluid bearing element 118 formed on the disc so that the leaf springs 260, 262 are horizontal when they are fairly parallel.

According to the present invention, a bias spring 266 is used to add a bias so that there is always a constant separation between the readhead 102 and the fluid bearing element 118 and the surface 7 of the disk 5. As the movable arm 100 progresses towards the center of the disk, it changes at relative surface speeds, with the fluid bearing gradually unable to support the readhead. Therefore, the lever 268 is initially rotated downward to extend to the spring 266 to give the downward force applied to the support arm 264 to bias the fluid bearing 118 when the fluid pressure is maximum. To be increased.

As the arm 100 moves inward of the disk 5 and the surface speed decreases, the cam ball arrangement gradually reduces the tension of the spring 266 while rotating the lever 268 in the upward direction while simultaneously reading head 102. Reduce the bias applied to

Properly contouring the cam allows the bias applied to the fluid bearing 118 to be maintained at an appropriate level so that the surface velocity of the disk is constant at any radial position.

An air bearing device 225 is used to allow relative motion between the readhead 102 and the turntable 106 supporting the disk 5. The mirror systems 26 and 28 and 120 and 28, respectively, to which the servo systems 40 and 60 and the mirror drives 124 and 126 correspond to the paths of ship 4 in relation to the readhead 102. Has the function of the circuit to adjust. In particular, the movable mirror 26 or 28 passes through the head 102 along a central axis that changes the line speed 4 as it reflects the read line speed 4 tangentially and laterally along the track 9, respectively. do.

In FIG. 7 there is a cam and a cam hole device 108 which drives the lever 268 through a flexible cable 110 (also illustrated in FIG. 3), which cuts the cam 270 to the arm. In the outermost position of the 100, the cam ball 272 is positioned at the high position projection so that the head 102 is directed upward and not in contact with the periphery of the rotating disk 5.

As the arm 100 proceeds inward along the track, the cam ball 272 immediately proceeds toward the innermost point on the surface of the cam 2 70, with maximum bias on the readhead 102.

As the arm travels inward in the radial direction, the cam ball 272 also moves outward from the center of the cam 270, reducing the force exerted on the readhead 102.

The video disc reproducing apparatus illustrated in FIG. 8 arranges the read head 102 in an operating relationship with the turntable 106 supporting the video disc 5. The readhead 102 is supported by the read arm device 100 and is mounted on the vertical support arm 255 secured to the device 110 using the bracket 259. At this time, it is fixed using the leaf spring (260, 262). In this way, the lens 17 can be kept close to the surface 7 of the video disk 5. The fluid bearing support element 118 is actuated by securing it to the vertical element 256 of the readhead 102 so that the disc 5 and the fluid bearing support element 118 as the disc 5 rotates over the turntable 106. The fluid bearing is generated between The spring 266, arm 268 and cam and cam hole device 108 are provided with an adjustable bias arrangement to vary the force exerted on the readhead 102 in the normal direction relative to the disc, thus providing the head 102. The distance between the disk 5 and the head 102 is kept constant regardless of its radial position.

Elastic elements 260 and 262 are used to install the read heads 102 relative to the vertical head support elements 258 and allow them to fully support the weight of the read heads 102.

The cam and the cam ball incorporate a portion of the device 108 into the adjustable bias element to function as a bias control circuit. These cams and cam holes connect the device 108 between the readhead 102 and the vertical head support element 256 so that they act in response to the radial position of the readhead 102 and are applied to the readhead 102. The bearing forces are varied to compensate for the different bearing forces distributed by the fluid bearings 118 due to the different surface velocities that appear as the radii of the discs are each different.

The readhead 102 is firmly connected to the fluid bearing support element 118 so that a constant gap is formed between the readhead 10 2 and the disc 5, which is the fluid bearing support element 118 and the disc 5. It is used to create a fluid bearing in between.

The cam and cam hole device 108 has a function to increase the bearing force on the head 102 as the head 102 moves radially toward the inside of the disk.

In the bias control circuit there is a cable 110 that connects the cam and the cam hole to the device 108 and the bias spring 266. The bias spring 266 is a compression spring and the function of the bias regeneration circuit selectively compresses the bias spring 266 such that the cam and the cam hole allow the device 108 to directly track the readhead.

As illustrated in FIG. 8, mechanical connection is provided to give a focus control function so that the lens 17 continues focusing on the information displays 10 and 11. The function of this connection is to move the objective lens relative to the surface 7 of the disc 5 along the portion 4c of the path of the beam of light 4 which impinges the objective lens so that the rotating disc 5 reads the head 102. It is to keep the focus of the ship speed (4) on the information track (9) as it moves laterally with respect to.

10 illustrates the installation of the Confucian mirror device in the readhead 102. The fixed mirror 120 and the Confucian mirror are disposed at the converging surface. The light beams incident in the horizontal direction impinge on the guiding mirror 28 and are rotated by 90 ° through a plurality of reflections between the guiding mirror and the fixed mirror 120 to be downward in the reading apparatus.

Similarly, the conveyed ship speeds follow the same path. The mirror 28 is a Confucian mirror that rotates around an axis inside the plane of the drawing to deflect the flux transmitted perpendicular to the plane of the drawing.

By controlling the angle of incidence of the mirror 120 and the angle of convergence between the mirrors 120 and 28, the incident flux is reflected by the two mirrors before entering the disc.

In addition, the pair of mirrors can be folded to give a light path and to rotate the beam at 90 °, thereby omitting a 45 ° mirror to increase the intensity of the available light applied to the disk. This, of course, ensures that at least extraordinary reflections occur between the mirror pairs without compromising the quality of the beam of light.

The same number of reflections can be obtained as in Figure 2, in which case there is no loss of light in the mirror as much as possible.

Claims (1)

In reading the information recorded in the information track on the surface of the disc, the light source device generating the reading flux for light radiation and the reading flux from the light source device along the U-folded optical path are directed to reach the information track. A video disc player, characterized by a linearity straightening device for modulating a reading flux on an information track and a sensing device for receiving modulated radiation flux from the information track.

Images