GB2151066A - Optical recording on cylinders - Google Patents
Optical recording on cylinders Download PDFInfo
- Publication number
- GB2151066A GB2151066A GB8334474A GB8334474A GB2151066A GB 2151066 A GB2151066 A GB 2151066A GB 8334474 A GB8334474 A GB 8334474A GB 8334474 A GB8334474 A GB 8334474A GB 2151066 A GB2151066 A GB 2151066A
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- Prior art keywords
- recording
- laser
- cylinders
- incidence
- cylinder
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
- G11B7/0065—Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B25/00—Apparatus characterised by the shape of record carrier employed but not specific to the method of recording or reproducing, e.g. dictating apparatus; Combinations of such apparatus
- G11B25/02—Apparatus characterised by the shape of record carrier employed but not specific to the method of recording or reproducing, e.g. dictating apparatus; Combinations of such apparatus using cylindrical record carriers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/002—Recording, reproducing or erasing systems characterised by the shape or form of the carrier
- G11B7/0025—Recording, reproducing or erasing systems characterised by the shape or form of the carrier with cylinders or cylinder-like carriers or cylindrical sections or flat carriers loaded onto a cylindrical surface, e.g. truncated cones
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
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- Optical Recording Or Reproduction (AREA)
Abstract
Optical memory cylinders and a system for recording thereon high density digital information by means of information modulated lasers, said lasers, normally in pairs, being co-operable, variably controllable as to intensity and angle of incidence and focussed to strike from opposing angles of incidence any recording position on a recording medium capable of physical change in reflective properties in response to predetermined levels of suitably matched laser radiation. Variation of the angle of incidence of the recording lasers permits recording and recovery of holographic data and cylinders may be operated in single cylinder versions or in multiple carousel versions in conjunction with more than one pair of recording lasers. Both erasable and non erasable methods of recording may be used and the system, enclosed in a suitable housing with appropriate window apertures may be used as a holographic camera. <IMAGE>
Description
SPECIFICATION
Optical memory cylinders and recording system
This invention relates to optical memory cylinders and a system for recording high density digital and or video information on curved and flat recording surfaces by means of information modulated lasers. Permanent records and records which are freely erasable and permit immediate re-writing are both within the scope of this invention.
In the context of this invention "cylinder" is to be taken to refer to whole closed cylinders, open strip cylinders and any curved surface derived from a sphere or cone. Lasers, in accordance with this invention, may be of fixed or variable intensity and may be provided as a single beam or, as is prefered, in one or more pairs of co-operable beams focussed to a common surface spot from opposing angles of incidence with means being provided for variably controlling the angle of incidence of the cylinder striking laser beam relative to either the radial or longitudinal plane of the cylinder. The dual beam recording method proposed herein is not however confined to recording on cylinders but may equally well be adapted for use in conjunction with spheres, domes, flat discs and records of multi-faceted geometry such as cubes.
Optical memory records in the form of flat discs are well known, the state of the art having advanced from discs that once recorded upon cannot be erased, to discs that can be recorded upon and erased repeatedly, the immediacy with which such discs can be erased and re-recorded upon depending on the type of recording medium used.
The operation of all such discs and recording systems relies essentially on one or more lasers of different wavelength, or alternatively, levels of pulsed laser radiation intensities impinging at a perpendicular angle of incidence upon the disc surface, causing a localised change in the optical properties and reflective qualities of the disc recording material surface so as to cause information modulated binary light levels which can be detected and thus read by suitable photoelectric transducing means.
In the case of non-erasable discs the general method is to cause a pattern of permanent micro-miniature deformations or punctures in either a light reflective or light absorb- tive layer of material forming the disc recording medium which surface or strata is normally a thin flim of metal.In the case of erasable discs the essential requirement is that the recording medium be of such a composition as to be capable of undergoing a reversible physical change in response to one of two contrasting pre-determined threshold levels of laser radiation intensity, one level corresponding to a writing level of intensiy, the other to an erasure level of intensity and both states being capable of being read nondestructively by a further level of radiation intensity which usually, but not exclusively, is a weaker level of radiation of pre-determined coherent light the wavelenghts of the respective laser lights being suitably matched to the recording material to make that material opaque and transparent to the respective laser beams.These latter desirable effects can be achieved through thermal melting of pigment doped thermoplastic, wax or resin based recording layers which may be used in conjunction with contrast intensifying means; through the stimulation of colour changes in photochromic crystal materials; through interference enhanced alterations in reflected light levels from optically sensitive thin films and through the exposure of photographic emulsions on a recording plate. Transmissive recording materials are also known.
An advantage of storing information on discs, be they magnetic or optical, is that their flatness enables removable discs of uniform size to be conveniently stored away together when not in use. This convenience is shared by cylinders in the form of open strip cylinders of uniform size. Also, discs readily lend themselves to being stack mounted in platters on a common spindle though this is less practical with optical discs. Open strip cylinders albeit of non-uniform size can, however, be nested within one another by standing on interlocking rings on top of turntables.
Discs do have, however, a number of major disadvantages. Firstly, by being circular the information tracks recorded thereon progressively diminish in size from the perimeter of the disc to the centre and thus the data tracks cannot store equal quantities of data. This makes complex programmed logic controls a necessity for formatting data storage. Secondly, for each point on the disc surface there is only one recording position relative to a fixed angle laser beam. Thirdly, the orientation of the disc surface relative to a fixed angle laser beam cannot be altered.
An object of this invention is to overcome the above mentioned disadvantages of recording on discs and to provide a flexible, multiple mode, high density and fast access information recording and playing system for use in varied data processing activities including: artificial intelligence applications in which paral lel as well as serial access to data is desirable; high resolution graphics and video; music synthesis; and holography applications.
The first mentioned disadvantage of discs is immediately overcome by the use of a cylinder as the support for the recording medium since information may be recorded linearly in tracks around the circumference or along the longitudinal length of the cylinder thereby ensuring uniformity in track storage capacities and greatly simplifying access logic controls to an X-Y format. The second mentioned disadvantage is overcome by the curvature of the cylinder surface which provides a multiplicity of recording positions for any given point on the surface when used in holographic applications. Thirdly, as will be seen later in this description, the orientation of a cylinder relative to a fixed angle of incidence laser beam does not present any problem.A variable angle of incidence laser beam relative to a fixed orientated cylinder is as achievable with a cylinder as it is with a disc, the important difference being that with a cylinder both variation in the cylinder orientation relative to the impinging laser beam and the angle of incidence of the laser beam relative to the cylinder are possible simultaneously by rotating the cylinder in a turntabled orbit about an adjustable laser radiating source.
Most of the known useful recording thin film material compositions and the respective laser writing, reading and erasing techniques used in conjunction with optical discs are suitable for use in accordance with the present invention.
Examples of suitable recording materials and their respective recording methods include the amorphous thermally deformed material disclosed in U.S. Patent 862069 (European Application 0,003,262) which comprises a thermoplastic binder incorporating an energy absorbing dye; the layer of 4-phenylazo-1-napthylamine disclosed in U.S. Patent 4,023,185; the Apiezon W wax or iodine doped cured epoxy resin coatings disclosed in
U.K. Patent Application 2,044,980 and the light absorbing sub-oxide of metal or semimetal consisting principally of Teo., (O. X 2.0) and sensitised by PbOx3 (O X3 1.0) disclosed in U.S. Patent 3,971,874, to mention a few. Also, the recording medium may be a photographic emulsion deposited on a metal or plastic plate cylinder for use in holography applications.A recording and playback method disclosed in Japanese Patent
Application 118468/78 (European Application 0,014,227) which makes changes of refractive index and absorbtion of light in a laser irradiated optically sensitive thin film disclosed in U.S. Patent 2,044,980 and which for playback employs a second focussed light to make interference between lights reflected by both incident surface and the inside face of the opposite surface of the thin film is also particularly suitable.
The practice of the present invention is not confined, however, to any one of the aforementioned material or recording techniques but may use any one suitable means alone or in combination with others according to the task to be accomplished. For example, a nonerasable record which may be a holographic record, used in conjunction with an erasable record is highly desirable in accounting systems where a permanent audit trail is required. In applying such materials and lasing techniques to a cylinder system considerable advantages are gained due to the curvature of the recording surface and the manner in which cylinders may be organised in relation to the laser focussing means. These include a high signal to noise ratio and the ability to controllably vary the angle of incidence of the impinging laser beams which is essential for best results in holography applications.Such recording means are also greatly improved by the use of a duality of co-operable writing/erasing/reading laser beams focussed to a common sport from opposing angles of incidence rather than a perpendicular angle of incidence although the latter is also useable. A third variable angle of incidence laser beam may usefully be employed as a reading beam in accordance with this invention.
According to thr present invention there is provided one or more demountable optical memory cylinders having a suitable recording material disposed upon at least one major surface of said cylinder and covered by a suitable protective layer as appropriate to the material used and such recording material being optically responsive to pre-determined threshold levels of information modulated laser impinging thereon; means for relasably securing one or more of said cylinders upon a system of one or more bi-directional motorised turntables or drum drive means for rotating the recording cylinders adjacent to and or orbitally about information modulated laser means comprising one or more pairs of cooperable, variably controllable angle of incidence variable intensity laser beams with means for directing and focussing said laser beams from opposing angles of incidence to strike any selected common surface spot upon the recording surface and recording thereon high density digital or video information which information is retrievable by suitable photoelectric transducing means provided in association with laser modulating means, the whole system being enclosed within a protective light tight housing.
The organisation of cylinder record relative to laser recording/playback means may take various forms in accordance with this invention. In a simple embodiment there may be provided a single closed whole cylinder operable in conjuncion with a single laser directing and focussing means on a one to one basis and be constructed within a housing of compact size comparable to currently available video discs systems. In this embodiment the cylinder may rotate on a motorised turntable or drum drive positioned adjacent to a variable angle of incidence laser read/write head which head is movable under servo motor control along a supportive arm so as to traverse the length of the cylinder and is also rotable upon a pivotal mounting to thereby vary the angle of incidence of the impinging laser beams.The recording material surface may be disposed on the interior surface of the cylinder or on the interior surface in addition to the exterior surface by means of a sandwich construction and the laser means may be so arranged as to access either one or both of said recording surfaces. The whole closed cylinder refered to may be split inti two halves to form a pair of open strip cylinders which may be saddle mounted on a drum drive and thus operable as a whole closed cylinder which is easy to store away when not in use.
One half of such a cylinder may hold a non erasable record and the other half may be freely erasable.
In an alternative embodiment of the invention there may be provided a multiplicity of dual laser focussing means mounted on a common or independent servo controlled arm and operable with a single whole closed cylinder or with one or more open strip cylinders as described above such that each of said laser means traverses an equal but different portion of the cylinder, for example a quarter.
The angle of incidence of the laser focussing and directing means is preferably controllably variable through 180 degrees radially to the cylinder. Open strip cylinders may be saddle mounted on a drum drive or may be nested within one another through insertion in individual interlocking mounting rings which may be selectively engageable to withdrawn from and return such cylinders to a non-recording or playing nested position, though in this case such cylinders have to be non-uniform in size.
The orientation of all such cylinders may be in a vertical, horizontal or any other suitable orientation. A horizontal orientation is useful when the recording material is an amorphous meltable substance such as wax and in this mode it is advantageous to arrange the laser focussing means to record upon the cylinder from beneath the cylinder and to erase from above or vice versa according to the material used so that gravity may help accentuate the recorded deformation into a diametrically positioned bump or crater and to flatten such bump or crater on erasure. As with closed cylinders and within the limitations of the recording material, open strip cylinders may have the recording medium disposed on both the convex and concave surfaces which are easily accessible to one or more laser focussing means.Other recording geometries may also be used in place of cylinders, for example a sphere or dome with little modification.
In another and no less preferred embodiment of the invention there is provided a multiplicity of cylinder supporting and rotatable turntables or drum drives integral to a major base turntable which is revolvable about a central hub, said hub supporting an arrangement of one or more fixed or variable angle of incidence dual laser focussing and directing means such that, in the manner of a carousel, the position of any recording cylinder may, by controlled rotation through 360 degrees of the major base turntable be controllably altered bi-directionally relative to the hub and thereby radially varying the angle of incidence of said laser beams relative to said cylinders, the supporting turntables for which may have common motor drive connected to them by means of a universal friction ring wheel mounted beneath the major base turntable or, as is prefered, by means of individual motors incorporated within each cylinder turntable or drum drive, the active elements of such system being under programmed microprocessor control. The variations mentioned in connection with the previous example embodiments may also be applied in this embodiment. It may be noted that when a drum drive is used in place of turntables the drive motors and associated electronics may be located within the drum interior thereby conserving space and helping to produce a compact size systerm.
The recording cylinders need not be unduly large in size and thus may have a surface area comparable to that of standard video discs or they may be smaller or larger as best suits a particular application. Open strip cylinders may be any suitable proportion of a whole closed cylinder, for example a third, half or a quarter.
The substrate forming the cylinder wall preferably comprises an optically homogenous material the curved surfaces of which have an equal radius so that any point on the curved surface and the recording material disposed thereon may be regarded as a parallel sided plate. It is known that such plates do not deviate light rays impinging thereon but do displace them laterally. By use of two cooperable laser beams impinging from opposing angles of incidence such displacement and associated interference pattern can be made reversible, that is can be switched from side to side or end to end according to the relative orientation of the cylinder to the laser beams.The co-operable laser beams are cooperable in the sense that not only are they focussed to impinge on a common spot but also that they may be pulsed independently of one another or pulsed simultaneously according to whether data is being written to, read or erased from the cylinder, and further may also be operated divergently as well as convergently.
The turntables or drum drives on which the cylinders are mounted preferably have cylinder securing means conforming in shape to the end shape of the cylinders in the case of turntables, and to the internal curvature of the cylinders in the case of drum drives. Thus strip cylinders may be placed in line within a recess in one continous or outer ring to create a virtual closed cylinder or they may be bank nested inside each other by inserting their rims into a groved recess in concentrically placed rings and which rings, being mounted upon a turntable, are preferably selectably moveable ingto and out of the nested position and thereby into and out of exposure range of the laser focussing and directing means when engaged with a suitable drive mechanism.
Optionally, the securing rings may be removable so that they may be inverted to reverse their curvature and therby reverse the curvature of the exposed recording surface relative to the laser directing means.
When the present invention is practised with the use of turntables to support the recording cylinders it is preferable to provide a header or capping turntable system corresponding to the base turntables for lowering onto the upper ends of the recording cylinders to ensure stable, wobble free rotation, the capping being anchored to suitable rigid guide and supporting rods or pillars included within the system housing.
The housing in which cylinders and recording system are contained may be any suitable shape, for example cylindrical or box shape but preferably having at least two flat surfaces at right angles so that said housing may stand in a vertical or horizontal orientation. Preferably, the housing has a removable lid or service hatch to enable the insertion and removal of cylinders as well as periodic maintenance, and is light tight when such hatch is closed. A window apperture facing and corresponding to an adjacent cylinder recording surface is preferably disposed in a portion of the housing panelling and is covered by a light tight door; alternatively the window may comprise a fixed or movable slit, a pinhole or a camera lens and shutter so that the recording system may be operated as a holographic camera.
Since holographically recorded information may be overlaid or layered on a photographic plate by merely varying the angle of incidence of the recording laser and may be retrieved by similar variation of the angle of incidence of a reading beam, the present invention may both store and retrieve vast quantities of such data.
Such information may be stored in the form of pictures or text and may for example be an image of a page of a book. Preferably, such pages are first microfilmed to produce a microdot and said microdot is then holigraphically recorded upon the cylinder. It may even be possible to record holographic images on recording materials that are not a photographic emulsion, for example the light absorbing sub-oxide of metal or semi-metal disclosed in
U.S. Patent 3,971,874.
The essential features and further optional features of this invention will now be described by way of example and with reference to the accompanying drawings. Although the description is not complete it is believed to be in sufficient detail to enable any person knowledgeable or skilled in the art to construct a working example of this invention
Figure 1 is a side view of a single cylinder system useable in conjunction with one or more lasers in accordance with this invention;
Figure 2 is a side view of a system housing with window appertures for use in holographic recordings;
Figure 3 is a plan view of a multiple cylinder arrangement of orbital turntables surrounding a central hub;
Figure 4 shows in end section three variations of open strip cylinders;
Figure 5 is a plan view of a turntable supporting nested strip cylinders;;
Figure 6 shows a cross section of a strip of cylinder and thin film recording medium showing parallel sided plates and lateral displacement of reflected lights;
Figure 7 illustrates a side view of a cylindrical light shield with a spiral slit for use of the invention in conjunction with holographic recording;
Figure 8 represents a cross section of a strip of cylinder having an amorphous recording layer and showing displacement of material at a recording area in accordance with the invention.
Refering to Fig. 1 two strip cylinders 1 Et 2 are saddle mounted on drive drum 3 having drive shaft ends 4 8 5 for connection to a drive motor (not shown), said shaft ends being mounted within a base plate 4 and header plate 5 which may be secured within a housing by means of fastening holes 14, 15, 16, 8 1 7. Swivel mounted arms 8 s 9 are connected to base plate 4 and header plate 5 by means of securing pins 10, 11, 12, 8 13 respectively which pass through mounting holes 18, 19, 20 8 21 and support, in addition to laser emitting sources (not shown), beam focussing and directing means 22 (shown in block form), for directing one or more laser beams 24 onto the surface of recording cylinders 1 8 2 whereby at one level of radiation intensity a track of data 25 may be recorded on the cylinder surface, at another level of radiation intensity the data track may be erased and at a third nondestructive level of radiation intensity the data may be read photoelectrically either by means of variable intensity dual co-operable lasers 24 or by an additional laser or pair of laser beams 29 directed from photoelectric transducer means 28 arranged to monitor the difference in reflected light intensities from the recording surface 1 s 2.
The laser directing means 22 s 28 includes the necessary controllably moveable lenses, mirrors and prisms means 23 for varying the angle of incidence of the impinging laser beams which are normally focussed to overlap at a common spot on the recording surface relative to the longitudinal plane of the cylinder, variation in the angle of incidence relative to a radial plane of the cylinder being controlled by a swivelled movement of supporting arms 8 8 9 through up to 180 degrees of arc and along which arms said laser directing means may traverse under servo control.Slots 30 8 31 are provided in arms 8 8 9 to facilitate connection of a drive belt or steel band (not shown) having sprocket holes engageable with the teeth of a sproket drive wheel (not shown) to thereby apply controlled motor drive to the supporting arms, such belt or band being either continous loop or having ends terminating in a cassette arrangement in the manner of a spring loaded steel rule measure, and this mode of transport may also be used to traverse the laser directing means along its respective supporting arm.
Optical guide stripes 26 8 27 are preferably provided down the length of whole cylinders and at cylinder join edges in the case of strip cylinders to indicate the start and end of a data track and to facilitate the alignment of laser beams to a specific track position. The operational processes of the system are under microprocessor control and accordingly each variation in the angle of incidence of impinging laser beams may be caused to occur once every revolution of the cylinder or once every complete traverse of the cylinder length by the laser directing means or in any desired combination or sequence.
In Fig. 2 is shown a housing 32 having a lid 33 mounted on hinge 34 and within which housing the recording system is enclosed.
There may be disposed in the housing wall a recessed window apperture 37 or alternatively a slit 38, or a cemera lens and shutter or pinhole 39 moveable relative to the longitudinal axis of the cylinder, and coverable by means of light tigth door 35 mounted on sprung hinge 36 thereby permitting the use of the system as a holographic camera.Preferably, for this mode of operation the system is adapted to include the cylindrical light shield 99 of Fig. 7 which has a spiral slit 100, said shield being interposed between the recording cylinder and the housing wall, rotated by suitable drive means such that the window apperture 38 of Fig. 2 may be caused to move in a descending or ascending cycle according to the direction of rotation and in synchronism with internal recording cylinder and the external laser source illuminating the object or information to be recorded, thereby enabling information to be recorded sequentially over the surface of a cylinder with a photographic emulsion as the recording material.The small apperture provided by the shield thus serves to prevent the holographic image from spreading over a larg e area of the exposed cylinder and enables information to be densely packed, as each exposed image may be superposed by changing the direction of the reference recording beam by turntabled rotation of the recording cylinder. The external and internal laser beams are chosen to be of similar wavelength so that once the recording cylinder has been developed the sotored information may be retrieved by the internal laser system focussed at the appropriate angle of incidence, Moving holographic images may also be recorded by this method.
Fig. 3 illustrates a schematic plan view of an expanded version of the present invention and comprising multiple turntables 42, 43, 44 and 45 integral to a major base turntable 40 orbitally rotatable about a central hub 41 the multiple turntables supporting by means of drum drive 46 either a whole closed cylinder 48 or paired strip saddle mounted cylinders 52 or by means of recessed mounting rings 47 s 49 whole or strip cylinders 50 s 51, and the central hub supporting by means of guide arms or posts 53, 54, 55 s 56 an arrangement of fixed or variable angle of incidence laser directing means of the kind described with reference to Fig. 1 such that by progressive increments of rotation of base turntable 40 the laser beams impinging on selected and individually rotatingrcylinders the angle of incidence may be be controllably varied, said angle of incidence being believed to be useful up to 50 degress of arc.
Although four orbital turntables are shown in Fig. 3 the number is not confined to four but may be eight or as many as the size of an optimised system is arranged to accommodate, and they may be accessed sequentially or simultaneously as may be desired. The surface of the cylinders may be apportioned for storage of data or different cylinders may store different kinds of data, for example one cylinder may hold operational programs, another video information, another graphic information or holographic images or any combination of information mixed between cylinders as required.
As shown in Fig. 4 open strip cylinders may have the recording medium disposed on the internal or exterior surface, and a sandwich construction would permit a cylinder with two recording surfaces. In the drawing, the variations A, B s C have a substrate 60, 61 or 62 on which is disposed a layer of thin film recording material such as an amorphous wax medium 65 or light absorbing sub-oxide of metal semi-metal 63 and 64 respectively a protective coating 66 8 67 being provided in the case of the sub-oxide material 63 or 64, as has been described previously herein.
The plan view of Fig. 5 shows an option useable in accordance with this invention in conjunction with nested strip cylinders of nonuniform size 73, 74, 75 8 76 inserted in recessed rings and which may be moved into operating positions of said rings 69, 70, 71 and 72 on turntable 68.
Fig. 6 illustrates the principle of parallel sided flat plates within the curved surface of a cylinder 77 comprising a substrate of optically homogeonous material 78 coated with a layer of thin film recording material 79 having a protective coating 80, and the lateral displace- ment or phase shift of reflected lights 90, 91, 92 and 93 at the thin film boundaries 81, 83, 85, s 87 corresponding to flat plates 82, 84, 86 a 88 tangential to said boundaries, of incident light beam 89 impinging thereon and the reverse shifted reflected lights 95, 96, 97 s 98 of the opposing angle of incidence incident light beam 94, and which reflected lights interfere with each other.Provided that the incident beams 89 8 94 are equal in intensity as well as equal in angle of incidence then the reflected lights are also equal in intensity and amplitude and opposite phase. If one of the incident beams is increased in intensity to the recording threshold level of intensity for the recording medium then the medium undergoes a physical change depend- ing on the nature of the recording material.
With a light absorbing material some light energy is absorbed and redistributed, the transmissivity of the material is thus reduced and the reflectance of the material is increased and a determinable difference in reflectivity between recorded part and unrecorded part is thereby produced. The physical change may, by suitable selection of material, film thickness and laser wavelength, be confined to the co-efficient of light and refractive index as in the case of the sub-oxide of metal or semkmetal, or may include in addition a displacement in the density and specific volume of the medium such as amorphous wax materials resulting in the formation of ridged craters or pits such as is shown in Fig. 8, wherein cylinder 101 comprises a substrate 103 supporting an amorphous layer 102 with pits 104 s 105 with ridges 106 s 107 recorded thereon forming a close equivalent to the displaced reflection lights of Fig, 6.
Contrast intensifying means such as a highly reflective backing layer of aluminium (not shown) may be included behind the thin film recording material.
If both incident beams 89 s 94 are made equal and used to scan the cylinder surface a difference signal representing the recorded data bit may be extracted by suitable photoelectric transducing means of known type and amplified for reproduction. Alternatively, the difference in reflectivity of recorded and unrecorded parts may be used to modulate a single reading laser beam all such respective reading beams being operable at a non-destructive or zero physical change level of intensity.
Erasure of recorded information is achieved by the method most appropriate to the recording medium used on the cylinder substrates.
With some materials such as sub-oxide of metal as mentioned previously herein the recorded part is irradiated with a laser of energy level slightly lower than that used for recording and higher than that used for reproduction, whereas other materials such as the amorphous kind require to be raised above the recording threshold level of intensity so that, therefore, the material is re-melted and allowed to infill its previous cavity. With the present invention utilising co-operable variable intensity and variable angle of incidence laser beams all such methods are possible provided the laser wavelength and material sensitivity is properly matched.Additional variations, however, include raising the unrecorded parts to the same level as a recorded part and, more preferably, switching the accentuated position of a recorded part by reversing the angle of incidence of the impinging laser to reverse the direction of lateral displacement of reflected lights and therefore phase relative to one or more reading beams. A forward phase shift may thus represent a binary high, a reverse phase shift may represent a binary low.
Whether viewed as a change of angular direction relative to a norm or a change in phase, amplitude or intensity of light reflection a reversible switching state is apparent.
Thus has been described a flexible and highly versatile multiple mode optical recording and playback system together with the necessary optical memory records in the form of optical memory cylinders which greatly extend the useful ways of exploiting both erasable and non-erasable data as well as holograms.
Claims (11)
1. Multiple mode optical memory cylinders and a system for recording high density digital or video information on one or more.
curved or flat surfaces by means of one or more laser beams or pairs of co-operable, variably controllable angle of incidence variable intensity laser beams, directed and focussed to strike from opposing angles of incidence any selected common surface spot upon the recording surface and recording thereon, by means of information modulation of the laser beams, high density digital or video signals on a cylinder surface optically responsive to predetermined levels of information modulated laser radiation impinging thereon, and which information is retrievable by suitable photoelectric transducing means.
2. Recording meams as in Claim 1 in which the recording medium disposed on the the recording surface of the recording cylinders is capable of undergoing a reversible physical change in response to predetermined threshold levels of laser radiation impinging thereon to thereby provide a recording surface on which stored information may be erased and re-recorded at will
3. Recording means as in Claim 1 s 2 in which the recording medium once recorded upon by information modulated lasers is incapable of undergoing any reversible change and thereby provides a permanent record only.
4. Recording means as in Claim 1 combining the erasable and non erasable recording states refered to in Claims 2 s 3.
5. Recording cylinders as in Claim 1 in which the recording surface medium may be of any suitable or well known type such as thermally alterable pigment doped thermoplastic films, wax or resin based coatings, thin films of photocromic crystals or sub-oxide of metals and photographic emulsions said materials being selected in relation to the type and wavelength of the laser means employed and to the type of recording it is desired to perform, and which materials provide a suitable optically readable interference enhanced alterations in the level of reflected light from a scanning laser, either through phase changes in the refractive index and absorption of light of the material, through localised physical deformation of the material or through changes in the polarization of suitable sensitisers incorporated as the dopent agent.
6. Optical memory cylinders as in Claim 1 having a substrate comprising and optically homogenous material the curved surfaces of which have an equal radius thereby creating between opposite sides a parallel sided plate with the property of laterally displacing light rays impinging thereon such that by use of two co-operable laser beams impinging from opposing angles of incidence said lateral displacement and associated interference pattern can be made reversible and switched from side to side or end to end according to the relative orientation of the cylinder to the laser beams and to the thin film recording material disposed thereon.
7. Recording cylinders as in Claims 6 formed as whole closed cylinders or open strip cylinders of any suitable proportion.
8. Recording means as in any previous claim in which recording cylinders are demountable and may be arranged relative to one or more pairs of co-operable variable angle of incidence variable intensity lasers as a single entity mounted on a motorised turntable or drum drive enclosed within a suitable housing.
9. Recording means as in Claim 8 in which a multiplicity of recording cylinders are supported on individual rotatable turntables with an integral major base turntable revolvable about a central laser means supporting hub such that the position of any recording cylinder within the carousel may, by controlled rotation through 360 degrees of the major base turntable be controllably altered bidirectionally relative to the hub and thereby radially varying the angle of incidence of the laser beams to the cylinder surface.
10. Recording means as in Claims 8 8 9 in which the controlled variation in the angle of incidence of the impinging laser or lasers to a common surface spot permits the recording of and retrieval of holographical information recorded in overlaid layers on a recording medium comprised of photographic emulsion.
11. An optical cylinder memory recording system substantially as herein described and with reference to the accompanying drawings.
11. Cylinders and laser recording means as in any previous claim enclosed within a suitable light housing which housing incorporates a window apperture or light tight door or other closable opening such as a pinhole, movable slit or camera lens or lenses and mirrors so that the recording means may be adapted to include a cylindrical light shield with a spiral slit for interposing between recording cylinder and external laser image so that the recording means may be operated as a holographic camera.
12. Recording means as in any previous claim having laser directing and focussing means including moveable lenses, mirrors and prisms mounted on supporting arms moveable under microprocessor controll servo motor control to vary the position, angle of incidence and direction of the recording and retrieving laser beams relative to the cylinder surface which surface has optical guide stripes to facilitate the alignment of laser beams to specific useable recording tracks.
13. Recording means as aforementioned in which retrieval of recorded data is by means of a difference signal caused by lateral displacement of reflected lights, phase or polarity of recorded portions of the recording surface or by interference patterns relative to unrecorded portions and to one of more reading laser beams.
14. An optical cylinder memory and recording system substantially as herein described and with reference to the accompanying drawings.
CLAIMS
Amendments to the claims have been filed, and have the following effect:
Claims 1, 5, 6, 7, 12, and 14 above have been deleted or textually amended.
New or textually amended claims have been filed as follows:
Claims 8,9,1011, 13 above have been re-numbered as 5, 6, 7, 8 and 10 and their appendancies corrected.
1. A system for recording high density digital or video information on one or more curved or flat surfaces by means of one or more laser beams or pairs of co-operable, variably controllable variably controllable angle of incidence variable intensity laser beams, directed and focussed to strike from opposing angles of incidence any selected common surface spot upon the recording surface and recording thereon, by means of information modulation of the laser beams, high density digital or video signals on a cylinder surface optically responsive to predetermined levels of information modulated laser radiation impinging thereon and which information is retrievable by suitable photoelectric transducing means.
9. Recording means as in any previous claim having laser directing and focussing means including moveable lenses, mirrors and prisms mounted on supporting arms moveable under microprocessor controlled stepper motor control to vary the position, angle of incidence and direction of the recording and retrieving laser beams relative to the cylinder surface which surface has optical guide stripes to facilitate the alignment of laser beams to specific useable recording tracks.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8334474A GB2151066A (en) | 1983-12-23 | 1983-12-23 | Optical recording on cylinders |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8334474A GB2151066A (en) | 1983-12-23 | 1983-12-23 | Optical recording on cylinders |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8334474D0 GB8334474D0 (en) | 1984-02-01 |
| GB2151066A true GB2151066A (en) | 1985-07-10 |
Family
ID=10553846
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8334474A Withdrawn GB2151066A (en) | 1983-12-23 | 1983-12-23 | Optical recording on cylinders |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2151066A (en) |
Cited By (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0254749A1 (en) * | 1986-02-07 | 1988-02-03 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical memorizing device |
| EP0258459A1 (en) * | 1986-02-07 | 1988-03-09 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical information medium |
| EP0258461A1 (en) * | 1986-02-07 | 1988-03-09 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical information carrier and method for erasing the information of the same |
| EP0260327A1 (en) * | 1986-02-07 | 1988-03-23 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical memorization device |
| EP0292578A1 (en) * | 1986-12-15 | 1988-11-30 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Information storage device |
| EP0293494A1 (en) * | 1986-12-15 | 1988-12-07 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Memorizing device with moving information carriers |
| EP0293493A1 (en) * | 1986-12-15 | 1988-12-07 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical-mechanical memorizing device |
| EP0325838A2 (en) * | 1988-01-22 | 1989-08-02 | Energy Conversion Devices, Inc. | Optical data storage drum, drive, and method |
| EP0354028A1 (en) * | 1988-08-05 | 1990-02-07 | Crosfield Electronics Limited | Radiation scanning apparatus |
| GR880100345A (en) * | 1988-05-24 | 1990-03-12 | Inst Modelirovania | Optical storage device |
| EP0360144A2 (en) * | 1988-09-19 | 1990-03-28 | Hitachi, Ltd. | Optical memory device and information processing apparatus |
| EP0512852A1 (en) * | 1991-05-08 | 1992-11-11 | Gold Star Co. Ltd | Cylindrical optical record medium and driving apparatus thereof |
| US5504620A (en) * | 1991-08-28 | 1996-04-02 | Linotype-Hell Ag | Device for dividing an optical beam |
| EP0750308A1 (en) * | 1995-06-23 | 1996-12-27 | Toshinobu Futagawa | High speed information read/write system |
| GB2335288A (en) * | 1998-02-10 | 1999-09-15 | Pennsylvania Pulp And Paper Co | Producing holographic patterns |
| US6388780B1 (en) | 2000-05-11 | 2002-05-14 | Illinois Tool Works Inc. | Hologram production technique |
| US6608800B2 (en) * | 1998-09-30 | 2003-08-19 | Howard Hong-Dough Lee | Optical data-storage apparatus employing optical media with three-dimensional data pattern |
| WO2006061361A1 (en) * | 2004-12-06 | 2006-06-15 | Tesa Ag | Method for producing cylindrical optical data memories |
| WO2006112284A1 (en) | 2005-04-13 | 2006-10-26 | Alps Electric Co., Ltd. | Recording medium and drive for the recording reproducing medium |
-
1983
- 1983-12-23 GB GB8334474A patent/GB2151066A/en not_active Withdrawn
Cited By (37)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0254749A4 (en) * | 1986-02-07 | 1988-09-28 | Akad Nauk Sssr | Optical memorizing device. |
| EP0254749A1 (en) * | 1986-02-07 | 1988-02-03 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical memorizing device |
| EP0258461A1 (en) * | 1986-02-07 | 1988-03-09 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical information carrier and method for erasing the information of the same |
| EP0260327A1 (en) * | 1986-02-07 | 1988-03-23 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical memorization device |
| EP0260327A4 (en) * | 1986-02-07 | 1988-09-07 | Akad Nauk Sssr | Optical memorization device. |
| EP0258461A4 (en) * | 1986-02-07 | 1988-09-07 | Akad Nauk Sssr | Optical information carrier and method for erasing the information of the same. |
| EP0258459A1 (en) * | 1986-02-07 | 1988-03-09 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical information medium |
| EP0258459A4 (en) * | 1986-02-07 | 1988-12-12 | Akad Nauk Sssr | Optical information medium. |
| EP0292578A1 (en) * | 1986-12-15 | 1988-11-30 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Information storage device |
| EP0293493A1 (en) * | 1986-12-15 | 1988-12-07 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Optical-mechanical memorizing device |
| EP0293494A1 (en) * | 1986-12-15 | 1988-12-07 | Institut Problem Modelirovania V Energetike Akademii Nauk Ukrainskoi Ssr | Memorizing device with moving information carriers |
| EP0292578A4 (en) * | 1986-12-15 | 1988-12-12 | Akad Nauk Sssr | Information storage device. |
| EP0293493A4 (en) * | 1986-12-15 | 1989-02-07 | Akad Nauk Sssr | Optical-mechanical memorizing device. |
| EP0293494A4 (en) * | 1986-12-15 | 1989-02-23 | Akad Nauk Sssr | Memorizing device with moving information carriers. |
| EP0325838A3 (en) * | 1988-01-22 | 1990-07-25 | Energy Conversion Devices, Inc. | Optical data storage drum, drive, and method |
| EP0325838A2 (en) * | 1988-01-22 | 1989-08-02 | Energy Conversion Devices, Inc. | Optical data storage drum, drive, and method |
| GR880100345A (en) * | 1988-05-24 | 1990-03-12 | Inst Modelirovania | Optical storage device |
| EP0354028A1 (en) * | 1988-08-05 | 1990-02-07 | Crosfield Electronics Limited | Radiation scanning apparatus |
| US5011245A (en) * | 1988-08-05 | 1991-04-30 | Crosfield Electronics Limited | Radiation scanning apparatus |
| EP0360144A2 (en) * | 1988-09-19 | 1990-03-28 | Hitachi, Ltd. | Optical memory device and information processing apparatus |
| EP0360144A3 (en) * | 1988-09-19 | 1992-04-22 | Hitachi, Ltd. | Optical memory device and information processing apparatus |
| US5109374A (en) * | 1988-09-19 | 1992-04-28 | Hitachi, Ltd. | Small-sized optical memory device and information processing apparatus utilizing cylindrically shaped information recording medium |
| EP0512852A1 (en) * | 1991-05-08 | 1992-11-11 | Gold Star Co. Ltd | Cylindrical optical record medium and driving apparatus thereof |
| US5504620A (en) * | 1991-08-28 | 1996-04-02 | Linotype-Hell Ag | Device for dividing an optical beam |
| US5754517A (en) * | 1995-06-23 | 1998-05-19 | Futagawa; Toshinobu | High speed information read/write system |
| EP0750308A1 (en) * | 1995-06-23 | 1996-12-27 | Toshinobu Futagawa | High speed information read/write system |
| GB2335288A (en) * | 1998-02-10 | 1999-09-15 | Pennsylvania Pulp And Paper Co | Producing holographic patterns |
| GB2335288B (en) * | 1998-02-10 | 2002-03-13 | Pennsylvania Pulp And Paper Co | Holography apparatus, method and product |
| US6549309B1 (en) | 1998-02-10 | 2003-04-15 | Illinois Tool Works Inc. | Holography apparatus, method and product |
| US6608800B2 (en) * | 1998-09-30 | 2003-08-19 | Howard Hong-Dough Lee | Optical data-storage apparatus employing optical media with three-dimensional data pattern |
| WO2003091991A1 (en) * | 1998-09-30 | 2003-11-06 | Howard Hong-Dough Lee | Optical data-storage apparatus employing optical media with three-dimensional data pattern |
| US6388780B1 (en) | 2000-05-11 | 2002-05-14 | Illinois Tool Works Inc. | Hologram production technique |
| US6567193B2 (en) | 2000-05-11 | 2003-05-20 | Illinois Tool Works, Inc. | Hologram production technique |
| WO2006061361A1 (en) * | 2004-12-06 | 2006-06-15 | Tesa Ag | Method for producing cylindrical optical data memories |
| WO2006112284A1 (en) | 2005-04-13 | 2006-10-26 | Alps Electric Co., Ltd. | Recording medium and drive for the recording reproducing medium |
| EP1879184A1 (en) * | 2005-04-13 | 2008-01-16 | Alps Electric Co., Ltd. | Recording medium and drive for the recording reproducing medium |
| EP1879184A4 (en) * | 2005-04-13 | 2008-12-24 | Alps Electric Co Ltd | Recording medium and drive for the recording reproducing medium |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8334474D0 (en) | 1984-02-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |