DE3804752C1 - Digital optical read-only memory and method of tracking control in such an optical read-only memory - Google Patents

Digital optical read-only memory and method of tracking control in such an optical read-only memory

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Publication number
DE3804752C1
DE3804752C1 DE19883804752 DE3804752A DE3804752C1 DE 3804752 C1 DE3804752 C1 DE 3804752C1 DE 19883804752 DE19883804752 DE 19883804752 DE 3804752 A DE3804752 A DE 3804752A DE 3804752 C1 DE3804752 C1 DE 3804752C1
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Germany
Prior art keywords
memory
electromagnetic radiation
track
read
information
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
DE19883804752
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German (de)
Inventor
Norbert Dipl.-Phys. Dr. 8011 Egmating De Kniffler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Airbus Defence and Space GmbH
Original Assignee
Messerschmitt Bolkow Blohm AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Messerschmitt Bolkow Blohm AG filed Critical Messerschmitt Bolkow Blohm AG
Priority to DE19883804752 priority Critical patent/DE3804752C1/en
Application granted granted Critical
Publication of DE3804752C1 publication Critical patent/DE3804752C1/en
Expired legal-status Critical Current

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Classifications

    • 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
    • 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
    • G11B7/0045—Recording
    • G11B7/00452—Recording involving bubble or bump forming
    • 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
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • 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
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
    • 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
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
    • G11B2007/24302—Metals or metalloids
    • G11B2007/24312—Metals or metalloids group 14 elements (e.g. Si, Ge, Sn)
    • 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
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
    • G11B7/2531—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising glass
    • 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
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
    • G11B7/2532—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising metals

Landscapes

  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

The invention relates to a use of a digital read-only memory as a mass storage means based on amorphous silicon, the read-only memory being designed in the form of an electrooptical bubble memory which has a guide track which is degraded by means of electromagnetic radiation and does not accept any information.

Description

Die Erfindung betrifft einen digitalen optischen Festwertspeicher, mit einem Substrat und mit einer auf dem Substrat angebrachten, aus hydro­ genisiertem amorphem Silizium (a-Si : H) bestehenden Aufzeichnungsschicht (nach M.A. Bosch, Appl. Phys. Lett., Vol 40, No. 1, Jan. 1982, S. 8-10) nach dem Oberbegriff des Anspruchs 1 und Verfahren zur Spurführung bei einem solchen optischen Festwertspeicher.The invention relates to a digital optical read-only memory, with a substrate and with one attached to the substrate, made of hydro Genized amorphous silicon (a-Si: H) existing recording layer (after M.A. Bosch, Appl. Phys. Lett., Vol 40, No. 1, Jan. 1982, pp. 8-10) according to the preamble of claim 1 and method for tracking in such an optical read-only memory.

Nach der angegebenen Literatur wird das amorphe Material (z. B. Silizium) auf Glas abgeschieden. Durch die Einwirkung eines scharf gebündelten Laserstrahls wird ein definierter Bereich stark erwärmt, so daß es zu einer Wasserstoffeffusion kommt, die durch Blasenbildung, Porosität oder Ablösung des a-Si-Filmes zu einer Reflexionsverminderung eines ähnlich fokussierten Laserstrahls führt.According to the given literature, the amorphous material (e.g. silicon) deposited on glass. By the action of a sharply focused A defined area is strongly heated by the laser beam, causing it to a hydrogen effusion that comes from blistering, porosity or Detachment of the a-Si film to reduce reflection similar focused laser beam.

Aus der Zeitschrift "Online-adl-Nachrichten", Heft 12, Seiten 946 u. 947 (Bild 3) und der DE 37 24 622 A1 ist es bekannt, bei optischen Datenspeichern Führungsspuren zu verwenden, wobei diese Führungsspuren Informationen enthalten oder informationslos sein können. Zum Einschrei­ ben wird elektromagnetische Strahlung in der o. .a Zeitschrift als Mög­ lichkeit benannt.From the magazine "Online-adl-Nachrichten", issue 12, pages 946 u. 947 (Figure 3) and DE 37 24 622 A1 it is known for optical Use data storage guide tracks, these guide tracks Contain or may be informationless. To scream ben is electromagnetic radiation in the above-mentioned magazine as Mög named named.

Aufgabe der Erfindung ist es einen digitalen optischen Festwertspeicher mit erleichterter Blasenbildung zu schaffen.The object of the invention is a digital optical read-only memory create with easier blistering.

Die Erfindung bezieht sich auf die Lösung gemäß Anspruch 1. In den An­ sprüchen 2 und 3 sind einfache Verfahren zur Spurführung bei einem Speicher nach Anspruch 1 enthalten. Verwendet man im Gegensatz zum Glas das Metall Titan als Unterlage, so ist der Einbau von Wasserstoff ins­ besondere in der Grenzschicht Titan/a-Si begünstigt, da Titan ein Was­ serstoffgetter ist. Dies wird durch Fig. 1 demonstriert. Es handelt sich hier um eine a-Si-Solarzelle mit Ti-Unterlage, die bei 250°C präpariert wurde. Man erkennt deutlich die Blasenbildung, die durch die Wasser­ stoffeffusion verursacht wird. Durch eine Präparation bei niedrigeren Substrattemperaturen kann die Effusion verhindert werden, die jedoch dann bei Laserbestrahlung einsetzt. Es erfolgt dadurch eine Blasenbil­ dung bei kleineren Laserleistungen bzw. bei größeren Fokussen. The invention relates to the solution according to claim 1. In claims 2 and 3, simple methods for tracking in a memory according to claim 1 are included. If, in contrast to glass, the metal titanium is used as a base, the incorporation of hydrogen is particularly favored in the titanium / a-Si boundary layer, since titanium is a getter of hydrogen. This is demonstrated by Fig. 1. This is an a-Si solar cell with a Ti base, which was prepared at 250 ° C. One can clearly see the blistering caused by the hydrogen effusion. The effusion can be prevented by preparation at lower substrate temperatures, but this then begins with laser irradiation. This results in a bubble formation with smaller laser powers or with larger foci.

Ein weiterer Vorteil ist die Ausnutzung der Vielstrahlinterferenz zur Reflexionserhöhung im unbestrahlten Gebiet, siehe Fig. 2, durch eine ge­ eignete Lichtwellenlänge und a-Si:H-Schichtdicke.Another advantage is the use of multi-beam interference to increase reflection in the unirradiated area, see FIG. 2, by a suitable light wavelength and a-Si: H layer thickness.

Weitere Vorteile solcher Speicherarten sind:Other advantages of such storage types are:

  • 1. Auswechselbare Platten, da Licht als Abtastmedium verwendet wird (Bildplatte, Kompakt-Disk);1. Interchangeable plates because light is used as the scanning medium (Optical disc, compact disc);
  • 2. die hohen Speicherdichten für digitale Werte (digitale Speicherung von Musik → Kompakt-Disk).2. the high storage densities for digital values (digital storage from Music → Compact Disc).

Bei der Anwendung als digitaler Festwertspeicher (z. B. Kompakt-Disk) wäre ein Aufbau sinnvoll, der eine einfache Steuerung und Führung des Lichtabtastkopfes erlaubt. Dazu wäre der Vorschlag nach Fig. 3 anwend­ bar, bei dem anstelle des einfachen a-Si:H-Belages eine Solarzelle ver­ wendet wird, die ein Steuersignal für den Lasertastkopf liefert. Trifft der abtastende Laserstrahl nämlich eine Wölbung (die Solarzelle ist vom Kontakt abgelöst), liefert die Disk kein Signal, was in diesem Fall heißt, da der Laserstrahl in Spur läuft. Wenn ein Signal von der Disk kommt, steuert man den Lesekopf nach.When used as a digital read-only memory (e.g. compact disk), it would make sense to set up a structure that allows easy control and guidance of the light scanning head. For this purpose, the proposal would be to Figure 3 Applic bar in which, instead of a simple a-Si:. A solar cell is spent H-ver coating, which provides a control signal for the Lasertastkopf. If the scanning laser beam hits a bulge (the solar cell is detached from the contact), the disc does not provide any signal, which in this case means that the laser beam is on track. If a signal comes from the disc, you readjust the read head.

Zusätzlich zu der verringerten Wirksamkeit der Solarzelle durch die Wöl­ bung trifft noch ein Degradationseffekt beim Schreiben einer solchen Blase auf. Dies ist für die Nachlaufsteuerung von Vorteil.In addition to the reduced effectiveness of the solar cell due to the cloud exercise still has a degradation effect when writing one Bloat. This is advantageous for the follow-up control.

In der Zeichnung werden folgende Figuren dargestellt. Es zeigtThe following figures are shown in the drawing. It shows

Fig. 1 a-Si : H-Solarzelle mit Titan-Substrat (rechte Hälfte), auf der linken Hälfte befindet sich keine Titanunterlage. Die sichtbaren Kuppeln sind Wasserstoffblasen. Die Kringel mit den scharfen Außenkonturen sind Blasen, die während des Herstellungsprozesses entstanden sind und platzten, so daß bei der weiteren Abschei­ dung eine Vertiefung zurückblieb; Fig. 1 a-Si: H solar cell with titanium substrate (right half), there is no titanium base on the left half. The visible domes are hydrogen bubbles. The squiggles with the sharp outer contours are bubbles that have arisen and burst during the manufacturing process, so that a recess remained in the further deposition;

Fig. 2 zur Justierung der Vielstrahlinterferenzbedingung kann die Lichtwellenlänge des Leselasers und die Schichtdicke variiert werden. Die Wellenlänge des Schreiblasers zeigen für a-Si eine hohe Absorption; Fig. 2 for adjusting the multiple-beam interference condition, the optical wavelength of the reading laser and the layer thickness can be varied. The wavelength of the writing laser shows a high absorption for a-Si;

Fig. 3 Aufbau für ein Nachlaufsteuersignal, das direkt von der Disk kommt und nicht aus dem Informationssignal gewonnen werden muß. Wird die obige Anordnung am Ort (a) durch die Lichtquelle be­ leuchtet, so kann ein Stromsignal abgeleitet werden, da die Zelle auf dem Substrat aufliegt. Am Ort (b) muß der Strom über den dunkel gefärbten p-Zonenbereich abfließen, weshalb nur ein sehr kleiner Photostrom fließen kann. Der Widerstand der p-Zone kann durch die Dotierung beeinflußt werden. Eine Lesekopfnach­ laufsteuerung würde also automatisch zum Halten kommen, da der mittlere Photostrom einer rotierenden Disk auf einer Rille kleiner ist als außerhalb (für die Nachlaufsteuerung ist nur eine Steuerrichtung nötig, also braucht man kein Vorzeichen des Steuersignals). Da die Lichtquelle moduliert werden kann, ist eine kapazitive Signalauskopplung des Steuersignals für den Nachlauf möglich. Durch den zusätzlichen Lichtdegradationseffekt kann man so Degradationsspurrillen schaffen, die von der Nach­ laufsteuerung erkannt werden, aber keine Informationssignale liefern. Fig. 3 structure for a tracking control signal that comes directly from the disc and does not have to be obtained from the information signal. If the above arrangement at location (a) is illuminated by the light source, a current signal can be derived since the cell rests on the substrate. At location (b) , the current must flow out over the darkly colored p -zone area, which is why only a very small photocurrent can flow. The resistance of the p zone can be influenced by the doping. A read head after run control would come to a stop automatically, since the average photocurrent of a rotating disk on a groove is smaller than outside (only one control direction is required for the run control, so you do not need a sign of the control signal). Since the light source can be modulated, a capacitive decoupling of the control signal for the overrun is possible. Due to the additional light degradation effect, degradation tracks can be created that are recognized by the post-run control, but do not provide any information signals.

Claims (3)

1. Digitaler optischer Festwertspeicher, mit einem Substrat und mit einer auf dem Substrat angebrachten, aus hydrogenisiertem amorphem Silizium (a-Si : H) bestehenden Aufzeichnungsschicht, bei dem die Infor­ mation in Form von Blasen längs Spuren mit elektromagnetischer Strah­ lung, insbesondere mit der von einem Laser emittierten Strahlung, einer bestimmten Wellenlänge, aufgezeichnet wird, dadurch gekennzeichnet, daß das Substrat aus einem Titanwerkstoff besteht, welcher die Blasen­ bildung in der hydrogenisierten amorphen Siliziumschicht (a-Si : H) durch die Wasserstoffgetterung des Titanwerkstoffes bereits bei relativ gerin­ gen Intensitäten der elektromagnetischen Strahlung ermöglicht.1. Digital optical read-only memory, with a substrate and with an attached to the substrate, made of hydrogenated amorphous silicon (a-Si: H) existing recording layer, in which the information in the form of bubbles along traces with electromagnetic radiation, in particular with the radiation emitted by a laser, of a certain wavelength, is recorded, characterized in that the substrate consists of a titanium material which forms bubbles in the hydrogenated amorphous silicon layer (a-Si: H) by hydrogenation of the titanium material at relatively low temperatures Allows intensities of electromagnetic radiation. 2. Verfahren zur Spurführung bei einem digitalen optischen Fest­ wertspeicher nach dem Anspruch 1, dadurch gekennzeichnet,
  • - daß entweder eine mittels elektromagnetischer Strahlung geschrie­ bene, informationslose Spur oder eine bereits Informationen in Form von Blasen längs einer Spur enthaltende Informationsspur als Füh­ rungsspur verwendet wird,
  • - daß eine auf die Oberfläche der Aufzeichnungsschicht des Festwert­ speichers fokussierte elektromagnetische Strahlung eingestrahlt wird, wobei die lokal bestrahlten Bereiche des Festwertspeichers als Solarzelle wirken, und
  • - daß dem Festwertspeicher insgesamt ein Photostrom oder ein gemittel­ ter Photostrom entnommen wird, dessen Wert ein Maß dafür ist, ob der Fokus der elektromagnetischen Strahlung auf die Führungsspur einge­ stellt ist.
2. A method for tracking in a digital optical fixed value memory according to claim 1, characterized in that
  • - That either an information-free track written by means of electromagnetic radiation or an information track already containing information in the form of bubbles along a track is used as a guide track,
  • - That an electromagnetic radiation focused on the surface of the recording layer of the read-only memory is irradiated, the locally irradiated areas of the read-only memory acting as a solar cell, and
  • - That a total of a photocurrent or a mean ter photocurrent is taken from the read-only memory, the value of which is a measure of whether the focus of the electromagnetic radiation is on the guide track.
3. Verfahren zur Spurführung bei einem digitalen optischen Festwert­ speicher nach dem Anspruch 1, dadurch gekennzeichnet,
  • - daß entweder eine mittels elektromagnetischer Strahlung geschrie­ bene, informationslose Spur oder eine bereits Informationen in Form von Blasen längs einer Spur enthaltene Informationsspur als Füh­ rungsspur verwendet wird,
  • - daß eine auf die Oberfläche der Aufzeichnungsschicht des Festwert­ speichers fokussierte elektromagnetische Strahlung eingestrahlt wird, und
  • - daß diese Strahlung zwischen der der Aufzeichnungsschicht des Sub­ strats zugewandten Oberfläche des Substrats und der äußeren Ober­ fläche der Aufzeichnungsschicht mehrfach reflektiert wird, wobei die entstehenden Teilbündel der Strahlung miteinander interferieren und daß die Einstellung auf die Führungsspur aus der Intensität der vom Festwertspeicher reflektierten Strahlung ermittelt wird.
3. Method for tracking in a digital optical fixed value memory according to claim 1, characterized in that
  • - That either an information-free track written by means of electromagnetic radiation or an information track already contained in the form of bubbles along a track is used as a guide track,
  • - That a focused electromagnetic radiation is radiated onto the surface of the recording layer of the fixed value memory, and
  • - That this radiation between the recording layer of the sub strate facing surface of the substrate and the outer upper surface of the recording layer is reflected several times, the resulting sub-bundles of radiation interfering with each other and that the setting on the guide track is determined from the intensity of the radiation reflected from the read-only memory becomes.
DE19883804752 1988-02-16 1988-02-16 Digital optical read-only memory and method of tracking control in such an optical read-only memory Expired DE3804752C1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19883804752 DE3804752C1 (en) 1988-02-16 1988-02-16 Digital optical read-only memory and method of tracking control in such an optical read-only memory

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19883804752 DE3804752C1 (en) 1988-02-16 1988-02-16 Digital optical read-only memory and method of tracking control in such an optical read-only memory

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DE3804752C1 true DE3804752C1 (en) 1989-07-13

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3306538A1 (en) * 1982-02-24 1983-09-15 Pioneer Video Corp., Nakakoma, Yamanashi OPTICAL DATA RECORDING PLATE
DE3724622A1 (en) * 1986-07-25 1988-01-28 Ricoh Kk Optical information storage medium

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3306538A1 (en) * 1982-02-24 1983-09-15 Pioneer Video Corp., Nakakoma, Yamanashi OPTICAL DATA RECORDING PLATE
DE3724622A1 (en) * 1986-07-25 1988-01-28 Ricoh Kk Optical information storage medium

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Applied ,Physics Letters, Bd. 40, Nr.1, Januar 1982, S. 8-10 *
Online-adl-nachrichten, Heft 12, 1978, S. 946 u. 947 *

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