JPS58161153A - Information handling unit - 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 The present invention relates to an information recording device, and more specifically
The present invention relates to an apparatus for recording information using a light beam of suitable intensity to define a photoresponsive thin film on an optically readable disc.

The carriage carrying the objective lens is movable radially with respect to the disk. The path section of the beam is parallel to the direction of movement of the carriage.

Various schemes have been developed for recording signals at video frequencies on disk tape or other media. These methods have utilized optical recording on photosensitive media, electron beam recording on thermoplastic surfaces, and other methods for reproducible recording of video information, among others.

Prior art techniques utilize photographic surfaces, electron beam sensitive surfaces, magnetic recording techniques, and techniques similar to the present invention in which radiant energy beams produce irreversible changes to the surface and thereby :Write 1 piece of information and enter.”
However, this method (two human bodies can be classified).

The photographic system is described in U.S. Pat. 2, which teaches photographic recording of video information.
No. 3,361,873, owned by Earl Johnson.

U.S. Patent No. 328 owned by W.C. Hughes et al.
No. 3310 describes the recording of information on a thermoplastic film surface-1, which is similar to U.S. Pat.
Using an electron beam writing device as disclosed in No. 0991 1. ing.

The method of sealing and ponding is also a special record! One such method is disclosed in US Pat. No. 33 SOS 03, owned by TB Bulletin Corporation, for recording information on the medium 4-. Ike's scheme, which utilizes an electron beam to a photosensitive medium Y such as photographic film, is taught in US Pat. No. 3,444,317, owned by R.F. Teuppe et al.

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

These methods are described in the magazine ``Electronics (Ele
ctronics) J March 8, 1969 Issue No. 1
It is discussed in detail on page 10. Additionally, the "Laser Thermal Microimage" is described in some detail by C.O. Carlson and H.D. Ives in i! '368 WESCON Meeting (Western Elect, Roni
c 5hou+and Convention), and this paper was published by WESCOHTpch
nical Papers) Volume 12, 1968 (published on page 1 of Section 1G/1).

This author was published on December 23, 1966 in "5science", Volume 54, No. 3756, No. 1.
S 5 (1-1551 negative, 1 ri (56 years) All Noyoi/G combination.

- all join;
CoInputer Conference')
Proceedings
) No. 71], pages -716, and “
Bell Systems' Technical Nyanar (Be1
l 5ystelIls Technicat
Journal) No. 385, page 405.

These publications disclose a recording technique that utilizes a very thin metal film on a substrate (62), which is heated and rapidly melts and recorded within a nano-bond (6). This creates a small spherule.The altitude of the laser beam is two-fold focused, and the bond burns by giving 7 minutes of heat in 1-minute of time. The modulated laser beam can produce a pattern of holes in the metal surface, allowing the recorded information to be reproduced during read-back.

As pointed out in the Carlson and Ives article cited above, the size of the recorded hole F or aperture can be as much as 61 minutes smaller than the diameter of the imaging laser beam. It depends on the appropriate selection of metal film material, film thickness, laser dieper diem and spot power, and the design of an appropriate scheme for recording video frequencies at high resolution.

In accordance with the present invention, the Carlson and Ives laser thermal microimage recording method is used in conjunction with prior art disk recording to create a new and useful arrangement and method for recording video information.

The present invention provides an information recording device for storing information, such as video information, in the form of convergent optically readable indicia.

The writing device of the present invention includes a laser light source that provides a collimated beam of sufficient intensity to rotate the disk uniformly and interact with the responsive coating of the disk. 6- The two optical path portions that limit the optical path to 1111 with the responsive coating are parallel to the disk surface. 11j The thin coating has an objective lens to focus the optical beam. A light intensity modulator or an optical path in the optical path 1) and responsive to the information signal to intensity modulate the light beam.

The objective lens is mounted on a carriage that is movable radially with respect to the disk. The direction of carriage movement is
parallel to the optical path portion that is parallel to the disk surface. This ensures that the laser source is held rigidly and at the same time allows the beam path to move radially across the disk without disturbing the critical alignment between the laser beam source and the objective lens. It is something that makes you.

A drive is provided for controllably moving the carriage relative to the disk during the recording process.

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 guard region of 1 μm between spots on adjacent tracks.

The write head 4 in a preferred embodiment is an air bearing.
A microscope objective lens that floats at a constant height above the disk of the microscope. 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 micron beat 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. In accordance with the invention, a "read-after-write" capability is provided to monitor write operations. A second, helium-neon (l]e-N (heat) readout laser is provided, which directs a lower power beam into the write beam path or The beam is oriented at a slight angle to the beam.
The read beam is selected to illuminate an area on the written trunk that is approximately 2 μm below the write or bond.

The second read beam is reflected from the disk surface back through the write path and the dichroic wave (clichr.ic 1nirr) is generated by inserting the subsequent beam into the write path.
The optical path is returned to ar>.

The read beam is then directed through a beam splinter and then through a mirror or filter which blocks any write beam that may have followed the same path. The readout beam then impinges on a photodetector to generate a video information signal. The characteristics of this signal are displayed on an oscilloscope or television monitor to indicate peak recording power, average recording power, and whether focus is accurate.

10- [Read After Write] information can also be utilized in an error checking scheme, especially when dental 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, check 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 "henod" at a constant speed along the radius of the rotating disk. As can be seen, it is required that the drives of 2-) be synchronized or otherwise cooperated so that a helical track of a predetermined pinch can be created. If desired, concentric circles can also be created by alternating northing and writing.

In a preferred embodiment using a spiral, the spacing between adjacent spiral turns is −10=2 μm from center to center. If the spot diameter is 1 μIn, there is a guard region of 1 μIn between spots in adjacent ranks.

The novel features believed to be characteristic of the invention, together with further objects and advantages thereof, with respect to the mechanism and method of operation, are set forth in the appendix herein by way of preferred embodiments or examples of the invention. 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.

First, if you look at the first item, the writing device is used, 181
2), which means that in this example ′ζ is
This is a dry microscope lens 14 with an air bearing support member 16 attached. It has been found that a 4()× lens is satisfactory. A disk 18 is specifically provided, which may be constructed according to the teachings of the prior art, in which the substrate is coated with a very thin film of a metal having a very low melting point and high surface tension. There is.

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 transfer nut, moves the write head 12 in the radial direction of the rotating disk 18+2ttl. The carriage 28 is provided with suitable mirrors and lenses on which the remainder of the necessary optical and electronic systems are permanently mounted.

In the second embodiment of the invention, a polarization splitting laser; (0,
The beam (which is an argon ion laser) passes through a Pockels cell 32 which is driven by a Pockels cell driver 34 . FM modulator 36 receives the video signal to be recorded and provides an overload control signal to Pockels cell driver 34. As is well known,
Pockels cell 32 responds to an applied signal voltage by rotating the plane of polarization of the light beam. Since the +fn line polarizer transmits light only in a predetermined plane of polarization, a polarizer such as the Glan prism 38 in the embodiment is inserted into the writing beam path to generate the modulated writing beam 40. give.

A modulated write beam 40 emerging from the Bonkel base cell 32 and Glan 7' rhythm 38 combination directs the write beam 40 to a first translating carriage 28.
It is applied to the mirror 12. The second mirror 42 maintains the energy level of the writing beam in response to the average intensity of the writing beam.

A portion of the writing beam 4 (1) is transmitted to the cell stabilization circuit 44.

A lens 46 is inserted into the path of the writing beam 40 and widened to fill the entrance hole of the objective lens 1, so as to diverge a substantially parallel beam and provide optimum resolution. All of the dichromatic mirror 48 or writing beam 40 is inserted into the arthroscope 50 of the second arthroscope 50 in a passageway oriented to be substantially transparent. A mirror 50 such as that shown in FIG.

Objective lens 14 and associated air bearing 16
effectively floats a portion of the air cushion at a substantially constant distance from the surface of disk 18. This distance 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 that can resolve a 1 μm spot is also 1 μm.
This certain amount of space is required because it is a unit of .

A second relatively low power laser 52 directs the monitor beam 5
Give 4. In an embodiment, readout laser 52 is a helium-neon device in which readout beam S4 is wavelength-excluded from the write beam. The polarizing beam splitting cube 5G transmits the readout beam 54 to a mirror 58 which directs the beam 14--through a second diverging lens 60 which spreads 4 into the readout beam and passes it through the objective lens 1.1. entry 1
] Make sure to fill the holes.

- A half-wave plate 62 is placed in the optical path in association with the plane polarizing beam splitter 5G, so that the light reflected from the disk 18 re-enters the laser 52 and mixes its oscillation modes. 4. 1/1 wavelength plate 6
2 rotates through the polarization plane of the beam every 45 degrees, so that the reflected beam is rotated 00 degrees relative to the polarizing beam splitter 56 and therefore does not pass through it.

A second mirror 64 in the readout beam 74 path transforms the beam into a dichroic m1rror' 48
The write and read beams are directed inward and impact the disk 18j:l2 downstream from the outgoing beam "spont" or "write beam beam" as described in further detail below. The passages of the passages are substantially the same (with limited adjustment).

A filter 6G, which is opaque to the argon ion beam, is inserted into the path beyond which it is reflected from the beam splitter S6. The 1-1e-Ne read beam 54 returned from the disk surface is 1. It can pass through filter 66 and lens 68 to photodetector 70.

The output of the photodetector 70 is sufficient for subsequent use 17)
The signal with amplitude and signal strength is applied to a preamplifier 72 where the signal is measured. A video discriminator 74 then provides a video output signal, which can be utilized in a variety of ways, two of which are shown by way of example only.

In the first application, the video output is the television monitor 7
6 and added to the onjiros hoop 78. tv set·
A monitor 76 indicates the video fidelity of the recording and an onjiro hoop 78 indicates the signal-to-noise ratio and canting quality of the recording.
Indicates whether it is light or heavy. Although not shown, an appropriate feed bank is used to ensure sufficient discrimination between the area of ``hole 4, i.e., ``black'' and ``white 4'', ie, ``white 4'' on disk 1-.・It is necessary to provide a loop.

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 write method and the v! of writing information. A delay equal to the time that elapses between # and the time required to reach the incremental region of the disk or the readout point must be imparted to the input video signal.

Ideally, the video output signal of discriminator 74 would be identical in all respects to the video input signal after an appropriate delay. The differences you see are defects on the surface of the disc,
Alternatively, it represents an error caused by the sensitization effect of the write circuit.

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

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

Illuminate write head assembly 12 onto rotating disk 18 7
Any known technique can be used to provide the radial translation. In the first example, the rotational and binary drives 20, 22 are shown independently, or they are synchronized by a common crystal oscillator 20 for each revolution of the disk 18. Write assembly 12 by predetermined increments
You can do one thing to make it translate.

Turning now to FIG. 2, the beam 40 from the write laser 30 and the read laser '52 are shown in somewhat exaggerated form.
A slightly different optical path of beam 54 from . The writing beam 40 is coincident with the optical axis of the microscope objective 4. The reading beam 54, in contrast, is at an angle a with the optical axis, so that the beam is aligned with the writing beam 4.
0 "downstream" from where it "cuts" to the =18- focus of the objective by a distance @X equal to 0 times the μ distance. The resulting delay between reading and writing causes the molten metal to solidify, whereupon the record is read in its final state.

If it is read out so quickly that the metal is still melted,
Not being given adequate information to adjust 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 on the optical axis of objective lens 14. In the direction of movement of the medium, away from point A, as indicated by the arrow,
There is a readout point B at an angle a from the axis of the microscope objective 4. A distance of 2 μm between points A and B provides satisfactory monitoring of write operations.

Turning finally to FIG. 4, an idealized diagram of the Pockels cell stabilization circuit 44 for use in the apparatus of FIG. 1 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 similar to a Grand prism).
The light is passed through a plane polarizer.

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

Depending on the individual Pockels cell, a voltage change of approximately 100 volts causes the cell to rotate the plane of polarization 360 degrees. h, the migration characteristics of individual cells are ±5 +')pol)
It can be changed arbitrarily according to the voltage change of
A feedback loop is desired to maintain the cell within a useful, reasonably linear operating range.

Stabilization circuit 44 includes a photosensitive silicon diode 82 positioned to receive a portion of write beam 40 reflected from 142 in FIG. This silicon diode 82 acts in much the same manner as a solar cell, providing a source of electrical energy when illuminated by incident 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 the voltage of a differential amplifier 86. Silicon cell 82 is shunted by a load 88 allowing a linear response mode.

The 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.
It is possible to set two.

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. Note 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 produces a differential voltage -2l= at the input to differential amplifier 86. Initially, the partial pressure gauge 90 is adjusted to produce a predetermined average level of strength. A correction voltage is then generated in differential amplifier 86 as the average level of intensity impinging on silicon cell 82 increases or decreases. The correction voltage applied to Pockels cell 32 is of sufficient polarity and magnitude to restore the average level intensity to a 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 sufficient 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, but
It is brought to the surface of the disk at a distance of -22=y [downstream] from the point of writing.

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

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

[Brief explanation of drawings]

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 Bonkels cell stabilization circuit. 18... Disc, 22... Rotation driving element, 1
2...Writing head, 20...Translational drive element,
30...Polarization splitting laser, 40...Writing beam,
32 Bonkers cell, 38-9 Grand Prism, 46... Objective lens, 16... Bearing,
50...Arthroscope, 52...Reading laser. ? 2B21

Claims (1)

[Claims] 1) an optical screen comprising means for generating an information signal to be recorded, a substrate covered with a photoresponsive thin film so as to carry an indicia of said information signal, and an optical screen of sufficient intensity to act on said thin film. a laser source for producing a parallel beam of light; and optical means for directing said beam onto said thin film of said disk of paragraph 11j, said beam being directed along an optical path that is partially parallel to the surface of said disk. an objective lens for focusing the beam onto the thin film; means for rotating the disk relative to the beam; and an open positioning of the laser source and the thin film of the disk. 11j; a light intensity modulating means for modulating the intensity of the light beam having information to be recorded; and a conveyor supporting at least the objective lens and moving relative to the laser source and the light intensity modulating means. and drive means for moving the transport means along said portion of said optical path and across said disk.