JPS58161159A - Information processor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Various schemes have been developed for recording signals at video frequencies on disk, tape or other media. These systems have utilized optical recording on photosensitive media, electron beam recording on thermoplastic surfaces, and other systems that provide reproducible recording of video information, among others.

Prior art techniques utilize photographic surfaces, electron beam sensing surfaces, magnetic recording techniques, and methods similar to those in the second invention in which a beam of radiant energy causes irreversible changes to the surface, thereby imparting information thereon. It can be roughly classified into ``writing'' methods.

Photographic systems are disclosed in U.S. Pat. No. 3,361,873, owned by W.R. Nlanson, which teaches the photographic recording of video information to a computer.

U.S. Patent No. 328 owned by W.C. Hughes et al.
No. 3310 describes the recording of information on thermoplastic film surfaces, which is similar to U.S. Pat.
An electron beam writing device such as that disclosed in No. 91 is utilized.

Note that other systems have also used electron beams to record information on special storage media. One such approach is disclosed in US Pat. No. 3,350,503 owned by TB Bullet. Another approach using an electron beam to a photosensitive medium such as photographic film is disclosed in U.S. Pat. No. 34, owned by R.F.
No. 44,317.

In recent years, other methods for high-density recording have been disclosed, based on removal of forest material by laser beam bombardment, or vapor deposition of material.

These methods are described in the magazine [Electroninox (Ele
ctronics) 4 March 8, 1969 Issue No. 11
It is discussed in detail on page 0. In addition, the ``Luther's Feverish Microimage Huda'' is described in some detail by C.O.
Carlson and H.D.
HoWa Convention) (One of the papers distributed at this event was explained, and this paper was
cal Papers) Volume 12 in 1968,
Published in section 16/1, page 1. This author was born on December 23, 1966.
ence) J Vol. 10-4-54, No. 3756, pp. 1550-1551, 1966
4 Fall Joint Compute
rConference) Proceedings No. 11-'716
Page, and [Bell Systems', March 1961'.
Technical Competition Journal (Be1l Systems
Technical Journal) No. 3
85. Also refers to the paper on page 405.

These publications disclose recording techniques that utilize very thin metal films on a substrate. The second thin metal film is heated and melts rapidly, creating small spherules within the recorded spot. A highly concentrated spot of laser light can impart enough heat in a short enough time that a suitably modulated laser beam impinging on a moving surface produces a pattern of holes in the metal surface. In addition, you can play back the recorded information when "reading back".

As pointed out in the Carlson and Ives article cited above, the size of the recorded spot or hole is much smaller than the diameter of the imaging laser beam. By appropriate selection of metal film material, film thickness, laser divergence and spot power, a suitable scheme for recording video frequencies at high resolution can be designed.

According to the present invention - the Carlson and Ives laser thermal micro-image recording method is used in conjunction with prior art disk recording to provide a new and useful arrangement and method for recording video information.

The present invention relates to an apparatus for processing information on a video disc.

The arrangement of the invention includes a spindle that rotates the disk in a precise circle, and a lead screw that translates the head at a very constant speed along the radius of the rotating disk.

The apparatus of the invention also includes a first light source that provides a light beam of sufficient intensity to interact with the coating of the record carrier as it rotates uniformly. The first optical device includes an objective lens for defining the optical path between the first light source and the coating of the record and focusing the light beam onto the coating. The apparatus of the invention further includes a second light source and a second optical device between the light source and the record carrier for focusing the reading beam onto the photoresponsive coating. The second optical device shares an objective lens with the first optical device.

As can be seen, it is desirable to synchronize or otherwise cooperate the drive of the disk with the translational drive to create a helical trajectory of a predetermined pitch. In a preferred embodiment, the spacing between adjacent turns of the helix is 2 μm from center to center.

If the spot diameter is 1 μm, there is a 1 μm wide area between the spots of adjacent tracks.

Whatever pattern is used, the writing beam from the first light source and the reading beam from the second light source are both radially directed with respect to the record carrier by moving the carriage carrying the first optical means and the second optical means. Moved.

The first optical beam directing means includes a first optical lens, a first optical beam directing means, and an objective lens. The second optical means includes a second
an optical lens, a second light beam direction is an apparatus, a third light beam is passed by the first light beam and is disposed between the first optical lens, the first light beam direction is the apparatus, and an objective lens; The direction includes a device.

The "writing spade" in the preferred embodiment is a microscope objective suspended at a constant height above a disk on an air bearing. This constant height is necessary because the depth of focus of the objective lens is shallow.

A 40X dry microscope objective was found to be satisfactory in focusing the energy of the laser beam and allowing the writing of a 1 μm spot at the disk surface.

A portion of the write beam is sensed by a novel Pockels cell stabilization circuit that helps maintain the average power of the beam for a given level modulation.

An argon ion laser is used as the writing beam. A Pockels cell and Glan prism combination modulates the laser beam with video information. According to the invention, a read-after-write capability is provided to monitor the write operation.
) A "readout" laser is provided, which directs a lower power beam into the write beam path, but at a slight angle to the write beam once it enters the write head. This angle is selected such that the read beam illuminates an area on the written track that is approximately 2 μm below the write spot.

This read beam is reflected from the disk surface back through the write head and passes through a dichroic mirror (m1rror) that has inserted the read beam into the write path.
) and then retraces its optical path.

The read beam is then directed to a beam splinter and further through a bandpass filter that blocks any write beam that follows the same path. The read beam then impinges on a photodetector 7 to produce a video information signal 10-. The characteristics of this signal are displayed on an oscilloscope or television monitor to "record" the peak values.
Indicates whether power, average recording power and focus are accurate.

[Read After Write] information can also be used in error checking schemes, especially when digital type information is being written. The input video information is delayed by a time equal to the time difference between the write spot and the read spot. The returned information is then compared for "identity" with the delayed input information. If there are too many discrepancies, recheck and realign the device or eliminate the disk.

The configuration of the invention includes a precision lathe that rotates the disk in a perfect circle and translates the recording head at a constant speed along the radius of the rotating disk. As can be seen, it is required that the two drives be synchronized or otherwise cooperate in order to be able to create a helical track of a given pitch. If desired, concentric circles can be created by alternating translation and writing.

In a preferred embodiment using a spiral, the spacing between the open turns of adjacent spirals is 2 μm from center to center.

If the spot diameter is 1 μm, there is a guard region of ] μm between spots in adjacent tracks.

The novel features believed to be characteristic of the invention, both as to its mechanism and method of operation, together with further objects and advantages thereof, are set forth in the appendix in which preferred embodiments of the invention are set forth by way of example. It will be better understood by considering the following description in conjunction with the drawings. It should be specifically understood, however, that the drawings are for purposes of illustration and description only and are not intended to limit the scope of the invention.

Referring first to FIG. 1, the writing device includes a writing head 12, which in this embodiment is a dry microscope objective 1 mounted on an air bearing support member 16.
It is 4. A 40X lens has been found to be satisfactory. Disc 18 is specially prepared,
This can be constructed according to the teachings of the prior art, in which the substrate is coated with a very thin film of a metal with a very low melting point and high surface tension.

A crystal oscillator 20 controls the driving elements. The disk 18 is rotated by a first rotary drive element 22 which is connected to a spindle 24 .

Second translational drive element 26 controls the position of write head 12 .

A translation carriage 28, which is driven by a translation drive element 26 through a lead screw and a translation nut, moves the write head 12 in a radial direction of the rotating disk 18. Carriage 28 is equipped with suitable mirrors and lenses so that the remainder of the optical and electronic systems necessary for the writing device are permanently mounted.

In an embodiment of the invention, a polarization splitting laser 30, (
The beam (this is an argon ion laser) passes through the Pockels cell 32 to be driven 13-1 to a Pockels cell driver 34.
FM modulator 36 receives the video signal to be recorded;
Appropriate control signals are provided to Pockels cell driver 34. As is well known, the signal type 11- applied to the Pockels cell 32 by rotating the plane of polarization of the light beam is
respond to. A linear polarizer is a Glan prism in an embodiment in which light is transmitted only in a predetermined plane of polarization.
A polarizer, such as , is placed in the writing beam path to provide a modulated writing beam 40.

A modulated writing beam 44.0 emerging from the Pockels cell 32 and Glan prism 38 combination is directed onto a first mirror 42 which directs the second writing beam 40 onto the translation carriage 28. This first fi 42 transmits a portion of the writing beam 40 to a Pockels cell stabilization circuit 44 that maintains the energy level of the beam in response to the average intensity of the writing beam.

A C lens 46 is inserted into the path of the writing beam 40 to diverge a substantially parallel beam that fills and expands the entry hole of the objective lens 14 to provide optimal resolution 14-. .Dichroic fIt48 is the writing beam 4
0 into a passageway directed to be substantially transparent to the second arthroscope 50. The various mirrors shown in Eliot's earlier patent application are also used in this invention. This joint 1!50 then directs the beam to the lens 14
The point of impact of the beam 40 can be changed at the surface F of the disk 18 by directing the beam 40 through the disk 18.

Objective lens 14 and associated air bearing 16
effectively floats on a cushion of air at a substantially constant distance from the surface of disk 18. This distance is
It is determined by the geometry of the bearing 16, the linear speed of the disk 18, and the force used to load the head against the disk 18. The focal tolerance of a lens capable of resolving a 1 μm spot is also in the unit of 1/jb, which reduces the need for this certain amount of space.

A second relatively low power laser 52 directs the monitor beam 5
4 is miserable. In an embodiment, readout laser 52 is a helium-on-wood device in which readout beam 54 can be erased from the write beam by wavelength. Polarizing beam splitting cube 56 transmits readout beam 54 to mirror 58 which directs beam 54 through a second diverging lens 60 which spreads readout beam 54 to fill the entrance aperture of objective lens 14. do.

A quarter-wave plate 62 is placed in the optical path in conjunction with the plane polarizing beam splitter 56 to prevent light reflected from the disk 18 from re-entering the laser 52 and perturbing its oscillation modes. To prevent. The quarter-wave plate 62 rotates the polarization plane of the beam by 45 degrees each time it passes;
The reflected beam is then directed to the polarizing beam splitter 56 at a 90° angle.
Rotate the plane and therefore do not pass through it.

A second mirror 64 in the readout beam 54 path makes the beam dichroic 1j (dichrc, ic a+1rror)
48, the writing and reading beams impinge on the disk 18, except that the reading beam "spot" impinges on the disk 18 downstream from the writing beam spot, as further described in detail below. Limited adjustments can be made so that the passages of the two are substantially the same.

A filter 66 opaque to the argon ion beam is inserted into the path of the light reflected from beam splitter 56 . The 1-(e-Ne readout beam 54 returned from the disk surface directs the filtration and lens 68 to aZヱ,
It can be passed onto a photodetector 70.

The output of photodetector 70 is applied to a preamplifier 72 which provides a signal with sufficient amplitude and signal strength for comparison and use. A video discriminator 74 then provides a video output signal which may be utilized in a variety of ways, two of which are shown by way of example only. Video output is applied to a television monitor 76 and an oscilloscope 78. The television monitor 7G shows the video quality of the recording1, and the oscilloscope 78 shows the signal-to-noise ratio of the recording and the quality of the cutting2. Indicates whether it is light or heavy. Although not shown, the openings between the "holes" or black 117- and the no-hole 4, or white areas are appropriate to ensure that there is sufficient discrimination on the disk. A feedback loop can be provided.

As an alternative use, the video output of discriminator 74 is applied to comparator 80. The other input of comparator 80 is taken from the video input signal, which is directed through delay line 81. The accumulated delay of the writing method and the delay equal to the time elapsed between the moment of writing the information and the opening of the time required for the incremental area of the disk to reach the reading point must be added to the input video signal and No.

Ideally, the video output signal of discriminator 74 should be identical in all respects to the video input signal after an appropriate delay. Differences to note are defects on the surface of the disc,
Alternatively, it represents an error caused by the adverse effects of the write circuit.

This application is important when writing digital information, but less critical when other information is recorded.

18- The output of the comparator circuit 80 can be quantified and counted so that an acceptable number of errors can be established for any disc. When the counted error exceeds the standard,
The write operation can be completed. If necessary, you can burn a new disc. Discs with excessive errors can then be reprocessed and serve as "new 4-discs" for subsequent recordings.

Well known techniques are available for radially translating write hand assembly 12 relative to rotating disk 18. In FIG. 1, a rotational and translational drive 20
．． 22 are shown independently, these drives are synchronized by a common crystal oscillator 20 to drive the disk 18.
The writing assembly 12 may be translated by a predetermined increment for each rotation of the writing assembly 12 .

Turning now to FIG. 2, the slightly different optical paths of beam 40 from write laser 30 and beam 54 from read laser 52 are shown, some exaggerated. The writing beam 40 coincides with the optical axis of the microscope objective 14. The subsequent beam 54, in contrast, makes an angle α with the optical axis, where the beam is displaced "downstream" from the writing beam 40 by a distance X equal to 0 times the focal length of the objective lens. . As a result, any delay between reading and writing causes the molten metal to solidify, whereupon the record is read in its final state.

If the metal is read out so quickly that it is mostly melted, it will not give adequate information to adjust the recording parameters.

This is best illustrated in Figure 3, where two points on the same information channel are shown offset.

Point A, which is the point of impact of writing beam 40, is shown to be at the optical axis of objective lens 14. Away from point A, in the direction of media movement, is a readout point B at an angle α from the axis of the wI microscope objective 14, as indicated by the arrow. A distance of 2 μm between points A and B provides satisfactory monitoring of write operations.

Turning finally to FIG. 4, a Pockels cell stabilization circuit 4 suitable for use in the apparatus of FIG.
An idealized 7-gram of 4 is shown. As is well known, a Pockels cell rotates the plane of polarization of applied light as a function of applied voltage.

Therefore, a Pockels cell is used to rotate a plane-polarized beam of light, and the rotated light is passed through a plane polarizer, such as a Grand prism.

The light emerging from the polarizer is amplitude modulated by the applied voltage.

Depending on the individual Pockels cell, approximately +00
A voltage change in volts causes the cell to rotate the plane of polarization 360 degrees. However, the transfer characteristics of an individual cell can be arbitrarily varied in response to voltage changes of ±50 volts, so a feedback loop is desirable to maintain the cell within a useful, reasonably linear operating range. It will be done.

Stabilization circuit 44 includes a photosensitive silicon diode 82 positioned to receive a portion of write beam 40 reflected from mirror 42 of FIG. This silicon diode 82 operates in much the same manner as a solar type 21-cell, providing a source of electrical energy when illuminated by an incident beam of light.

One terminal of the silicon diode 82 is connected to a common reference potential 84, represented by a conventional ground signal, and the other terminal is connected to one power source of a differential amplifier 86.

Silicon cell 82 is shunted by a load 88 allowing a linear response mode.

The other input of differential amplifier 86 is connected to common reference 84 through a suitable voltage divider 90. A power supply 92 is coupled to a voltage divider 90, which is coupled to a differential amplifier 86 to establish the average light level delivered by Pockels cell 32.
can be set.

A pair of output terminals of differential amplifier 86 are then connected to input terminals of Pockels cell 32 of FIG. 1 through resistive elements 94 and 96, respectively. It is noted that Pockels cell driver 34 is AC coupled to Pockels cell 32, while differential amplifier 86 is DC coupled to Pockels cell 32.

In operation, this scheme is activated. Light from the writing beam impinging on silicon diode 82 generates a differential voltage at the input to differential amplifier 86. at first,
The partial pressure meter 90 is adjusted to produce light at a predetermined average level of intensity. A correction voltage is then generated in differential amplifier 86 as the average level of intensity impinging on silicon cell 82 increases or decreases. pockels cell 3
The correction voltage applied to 2 is of sufficient polarity and magnitude to restore the average level strength to the predetermined level.

An improved video disc recording assembly has thus been demonstrated. A microscope objective mounted on an air bearing "floats" at a predetermined distance from the surface of the metallized disk. The metallized coating is such that the laser beam, under appropriate modulation, can emit enough energy to melt localized areas of its surface.

Under surface tension, the molten metal contracts leaving a distinct area approximately 1 micron in diameter.

A second low energy laser utilizing substantially the same optical path is directed through the same microscope objective;
It is brought to the surface of the disk a short distance "downstream" from the point of writing.

The read beam is returned through a suitable optical scheme that rejects the reflected energy of the write beam, allowing analysis of the information written on the disk.

The reproduction information, among other things, controls the intensity of the writing beam to ensure a proper "recording level" and determines whether an unacceptable number of errors are introduced in the recording process.

[Brief explanation of the drawing]

FIG. 1 is a schematic drawing of the device of the invention. FIG. 2 is a diagram of the optical path through the objective of FIG. 1; FIG. 3 is a diagram illustrating the relative spacing between the points of impact of the write beam and the read beam. FIG. 4 is a diagram of the novel Pockels cell stabilization circuit. 18... Disc, 22... Rotation drive element, 1
2...Writing head, 20...Translational drive element, 3
0...Polarization splitting laser, 40...Writing beam,
32 Pockels cell, 38Φ...Grand prism, 46...Objective lens, 16...Bearing, 5
0...Arthroscope, 52...Reading laser. 25-3C

Claims (1)

Claims: 1) a record carrier comprising a substrate having a surface covered with a responsive coating; a first light source for emitting a light beam; means for imparting a relative rotation of the light beam on said record carrier; a first light path between the first light source and the record carrier comprising a coating; a first optical device for focusing a light beam onto the coating by an objective lens; and a first optical device arranged in the optical path between the first light source and the recording carrier and modulating the intensity of the light beam carrying the information to be recorded. a second light source that generates a second light beam; an optical path is configured between the second light source and the recording carrier to generate the first light beam in the direction of movement of the substrate surface; The second light beam is focused by the objective lens on the coating -1- at a position remote from the point of incidence of the substrate, and the second light beam reflected by the surface of the substrate is collected. An information processing device comprising a second optical device that also has a second optical device and a sensing device that generates a corresponding electrical signal in response to reflected light, the information processing device being provided with a moving device;
In the information processing apparatus, the light beam incident on the substrate surface is moved together in the transverse direction with respect to the moving direction of the second substrate surface, wherein the first optical means or the first optical lens 46 and the first beam directing device 50 and the objective lens 14, the second optical means or the second optical lens 60, the second beam directing device 64, and the first beam directing device 50 and the objective lens 14; 1), the first optical lens 46 and the first beam direction device 50
The third beam director disposed between them includes a third beam director device 48, the first beam director device 50, and an objective lens 14; and further provided with a drive element for displacing the carrier in a radial direction with respect to the rotating recording carrier, the first optical lens and the first beam director being arranged in an optical path located at an angle to the apparatus. and a second optical lens and a second beam direction are such that the optical path portions located at the end of the device are approximately parallel to each other and to the movement produced by the carrier displacement device, and a third beam direction is such that the portions of the beam path are located in aperture with the device and are substantially parallel to each other and to the movement produced by the carrier displacement device. An information processing device characterized in that an optical path portion located opposite to an objective lens is provided so as to substantially cooperate with both light beams.