GB2221563A - Method of detecting the position of an optical head - Google Patents
Method of detecting the position of an optical head Download PDFInfo
- Publication number
- GB2221563A GB2221563A GB8922654A GB8922654A GB2221563A GB 2221563 A GB2221563 A GB 2221563A GB 8922654 A GB8922654 A GB 8922654A GB 8922654 A GB8922654 A GB 8922654A GB 2221563 A GB2221563 A GB 2221563A
- Authority
- GB
- United Kingdom
- Prior art keywords
- optical
- optical card
- track
- card
- optical head
- 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.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/01—Details
- G06K7/015—Aligning or centering of the sensing device with respect to the record carrier
-
- 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
- G11B7/0033—Recording, reproducing or erasing systems characterised by the shape or form of the carrier with cards or other card-like flat carriers, e.g. flat sheets of optical film
-
- 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
- G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
- G11B7/08505—Methods for track change, selection or preliminary positioning by moving the head
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L49/00—Packet switching elements
- H04L49/10—Packet switching elements characterised by the switching fabric construction
- H04L49/104—Asynchronous transfer mode [ATM] switching fabrics
- H04L49/105—ATM switching elements
- H04L49/106—ATM switching elements using space switching, e.g. crossbar or matrix
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Artificial Intelligence (AREA)
- Computer Vision & Pattern Recognition (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
In the method according to the present invention, before data are recorded on an optical card or the data recorded on the card are reproduced, an optical head for applying a light beam to the optical card and the optical card are displaced relative to each other in the direction of track of the optical card and a track number written on the optical card is read to thereby detect the position of the optical head relative to the optical card. The card includes a track 11 for tracking and a data track 12 with data track number for identifying the data tracks at both ends of each track 12. <IMAGE>
Description
TITLE OF THE INVENTION
Method of Detecting the Position of an Optical
Head
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to a method of detecting the position of an optical head in a recording-reproducing apparatus for recording or reproducing data on a card-like recording medium (hereinafter referred to as the optical card) by the use of a light beam, that is, detecting the relative positional relation of the optical head to the optical card before recording or reproduction of data is effected. The recordingreproducing apparatus referred to herein means an apparatus for effecting only one or both of recording and reproduction.
Related Background Art
In recent years, along with the advance of the informational age, attention has been paid to optical cards as information storing means. The main features of the optical cards are that as compared with optical discs and optical tapes, they are of a card-like shape which is easy to carry and handle and that as compared with magnetic cards and IC cards, they have a great storage capacity.
Now, in recording reproducing data through a storing medium such as an optical card, the relative positional relation between the optical card and the optical head in the initial state need be apparent before the recording or reproducing operation is started.
For example, generally, most recording-reproducing apparatus are in such a form that before said operation is started, the information of the area of contents which is provided in the optical card and in which the data situation or the like in the optical card is written is read and the operation is performed on the basis of that information. Accordingly, to shorten the time required for the recording or reproduction of data, it is necessary that after the optical card has been inserted into the apparatus or when the recording or reproducing operation once interrupted is to be resumed, the relative position of the optical head and the optical card be quickly moved to bring about a state in which the information of said area of contents can be reproduced.
Herein, the position in which the optical head is positioned in such a state relative to the optical card is called the home position of the optical head.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide a method of quickly detecting the position of an optical head to enable the optical head to quickly stand by at a predetermined position.
In the method according to the present invention, before data are recorded on an optical card or the data recorded on the card are reproduced, an optical head for applying a light beam to the optical card and the optical card are displaced relative to each other in the direction of track of the optical card and a track number written on the optical card is read to thereby detect the position of the optical head relative to the optical card.
The invention will hereinafter be described in detail.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows an embodiment of the optical card.
Figures 2 and 3 illustrate the detecting method according to the present invention.
Figure 4 shows an embodiment of the optical card recording-reproducing apparatus using the detecting method according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 is a schematic view showing an embodiment of the optical card. Reference numereal 1 designates the optical card, reference numeral 2 denotes an area in which data are recorded, and reference characters 3a, 3b and 3c represent track units. The track unit herein referred to means a combination of minimum necessary various tracks including, in addition to a data track on which data are written, a track for tracking for effecting thereon reliable writing and reading of data and a track for clock.
Figure 2 is a view for illustrating the method according to the present invention by the use of an optical card having a certain track unit. This certain track unit, as shown in Figure 2, consists of a track 11 for tracking and a data track 12. At the opposite ends of a data track 12, there are data track identification areas 13 in which data track numbers for identifying the data tracks are recorded.
Considering the initial state before writing or reading of data is effected, a beam spot 14a for scanning the track for data and a beam spot 15a for scanning the track for tracking lie generally at any positions on the optical card. In subsequence to this state, the optical head of an apparatus, not shown, is moved in the left to right direction as viewed in Figure 2 (the direction of movement of the track) and the autofocusing function and the auto-tracking function of a recording-reproducing apparatus are made to act by the reflected light from the beam spot 15a, whereby the light spot 14a for data and the light spot 15a for tracking are positioned on the nearest data track 12a and the track lla for tracking, respectively.The light spots 14a and 15a showing this state are designated by reference characters 14b and 15b, respectively.
Further, the light spots move and pass the data track identification area and as a result, the data track number 13a is read and thus, it becomes possible to know the relative positional relation between the optical head and the optical card at the current point of time.
Accordingly, after the above-described operation, the optical head can be moved to a desired track Mnit to thereby accomplish writing or reading of data easily.
For example, it becomes possible to read the data track number and known the relative positional relation between the optical head and the optical card. Accordingly, after the above-described operation, the optical head can be moved to a desired track unit to thereby accomplish writing or reading of data easily. For example, the data track number is read and the relative positional relation between the optical head and the optical card is recognized, whereafter the mutual positional relation is modified so that the optical head comes to the area of contents, and in this home position, a further command is had.
Means for giving a command for starting the relative movement in the track direction to know the positional relation between the optical card and the optical head may be for example, a signal from a sensor for confirming that the optical card has entered a predetermined position, or a manual signal given by the operator. As shown in Figure 2, data track identification areas are provided at the opposite sides of the data track, whereby it is conveniently possible to read the data track number by the movement of the optical head relative to the optical card either from right to left or from left to right.
As can be seen from the foregoing description, according to the present invention, access of the optical head can be accomplished by a simple system. Further, the present invention can cope with plural types of optical cards in which the shapes of the track units are the same but which differ from one another in the position and size of the data area 2 shown in Figure 1.
Figure 3 is a view for illustrating the method according to the present invention by the use of an optical card having the track units shown in Figure 2.
In Figure 3, elements functionally similar to those in Figure 2 are given similar reference characters.
The difference of the present embodiment from the embodiment shown in Figure 2 is that there are a plurality of light spots 14a for data Again in Figure 3, in the initial state, the two light spots 14a for data and the light spot 15a for tracking are at any positions on the optical card, but by the same operation as that previously described, the light spots 14a for data can be positioned on the nearest data tracks 12a and 12b, respectively, and the light spot 15a for tracking can be positioned on the track 15 for tracking and as a result, both of the data track numbers 13a and 13b can be read at a time. Accordingly, in addition to the aforementioned advantage that by the read data track.
numbers 13a and 13b being compared, the then position of the optical head can be judged, it becomes possible to know also the direction in which the track unit to be accessed in the next state is present. This gives rise to a practically very useful effect that the optical card shown in Figure 1 may be inserted into the optical recording-reproducing apparatus with either the
A side or the B side of the optical card as the leading side.
Altough the foregoing description has been made with respect to the type in which the optical head is moved, the optical card may of course be moved in the direction of movement of the track. Also, as regards the specific means for realizing the autofocusing and the auto-tracking function, the critical angle method, the knife edge method, the astigmatism method, etc. are known for the former and the 3-beam method, the push-pull method, the beterodyne method, etc. are known for the latter, and any of these methods is applicable. Furthermore, although the foregoing description has been made by the use of the data track numbers, it is also possible to set a tracking track number corresponding to the track for tracking and utilize it to detect the position of the optical head.
Figure 4 is a schematic diagram showing an embodiment of the optical card recording-reproducing apparatus using the detecting method according to the present invention.
In Figure 4, reference numeral 21 designates a sensor for mechanically or electrically detecting the insertion of the optical card 1 into the apparatus, reference numeral 22 denotes a DC motor driver, reference numeral 23 designates a DC motor for moving a table (not shown) supporting the optical card 1 thereon in the track directions of the card ( the directions of bilateral arrow), and reference numeral 24 denotes an optical head for applying three light beams to the optical card at a time as shown in
Figure 3. The construction of this optical head is similar to that of the optical head used with the conventional optical disc with the exception that a diffraction grating for separating the light beam from a light source into three light beams is provided, and the detailed construction thereof need not be described herein.Reference numeral 25 designates a circuit for reproducing the information recorded on the tracks from a signal read by the optical head as described in convention with Figures 2 and 3, reference numeral 26 denotes a comparator, reference numeral 27 designates a pulse operating circuit, reference numeral 28 denotes a setting circuit for setting to what position the optical head is to be subsequently moved relative to the optical card, reference numeral 29 designates a pulse motor driver, and reference numeral 30 denotes a pulse motor for moving the optical head 24 relative to the optical card 1.
When it detects the insertion of the optical card 1, the sensor 21 gives a detection signal to the
DC motor driver 22 and on the basis of this signal, the
DC motor driver 22 drives the DC motor 23 to move the optical card 1 in the direction of movement of the track. Simultaneously therewith, on the basis of a further detection signal from the sensor 21, the optical head 24 reads the information on two tracks on the optical card 1 at a time while performing the auto focusing and the auto-tracking function. From this reproduction signal, the reproducing circuit 25 indentifies the track number of each track and the information thereof is supplied to the comparator 26.
When it receives the result of comparison from the comparator 26, the pulse operating circuit 27 supplies the pulse motor driver 29 with a signal of the next track to be accessed by the optical head, with the value set by the setting circuit 28 as a reference, and the pulse motor driver 29 drives the pulse motor 30 to access the optical head 24 to a predetermined track.
By the above-described construction, it is possible to realize the method according to the present invention. In the description made with reference to Figure 4, an example in which the insertion of the optical card into the apparatus is detected to thereby start a series of operations has been shown, whereas this is not always restrictive. That is, the present method is of course applicable also to a case where with the optical card already inserted in the apparatus, recording or reproduction of data is done and the operation is once interrupted, whereafter recording or reproduction is again started.
The details and effect of the present invention have been described above with reference to the drawings. According to the present invention, before data are written into or read from the optical card, the optical card and the optical head are moved relative to each other in the direction of movement of the data track and the then relative positional relation between the two is known to thereby make it possible to quickly shift to the next operation.
Claims (6)
1. A method of detecting the position of an optical head for recording information on an optical card or reproducing the information recorded on the optical card, comprising the steps of:
instructing the optical head to record or reproduce; and
displacing the optical head relative to the optical card in the direction of track of the optical card on the basis of said instruction and reading the position information written on the optical card.
2. A method of detecting the position of an optical head for recording information on an optical card or reproducing the information recorded on the optical card, comprising the steps of:
detecting the recording or the reproduction being effected;
causing a light beam from the optical head to be accurately applied onto a track on the optical card;
moving the optical head and the optical card relative to each other in the direction of track of the optical card and reading the position information written on the optical card.
3. A method according to Claim 2, further comprising the step of moving said optical head to its home position on the basis of the read position information.
4. An apparatus capable of detecting the position of an optical head and effecting optical recording or reproduction, comprising:
means for instructing the optical head to record or reproduce; and
means for moving the optical head and an optical card relative to each other in the direction of track of the optical card on the basis of a signal from said instructing means.
Amendments to the claims have been filed as follows 1. An optical card bearing a plurality of linear tracks, comprising a tracking track and a data track, the data track or the tracking track having position information stored solely at each end of it.
2. An optical card according to claim 1, in which the position information is indicative of the position of the track relative to a target position.
3. An optical card according to claim 1 or claim 2, having a clock track.
4. An optical card according to any one of the preceding claims, in which the data track has position information stored at each end of it.
5. An optical card according to any one of claims 1 to 3, in which the tracking track has position information stored at each end of it.
6. An optical card substantially as described herein with reference to the accompanying drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60072042A JP2556465B2 (en) | 1985-04-05 | 1985-04-05 | Optical head access method for recording / reproducing apparatus |
| GB8608345A GB2174531B (en) | 1985-04-05 | 1986-04-04 | Moving an optical head |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8922654D0 GB8922654D0 (en) | 1989-11-22 |
| GB2221563A true GB2221563A (en) | 1990-02-07 |
| GB2221563B GB2221563B (en) | 1990-06-20 |
Family
ID=26290597
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8922654A Expired - Lifetime GB2221563B (en) | 1985-04-05 | 1989-10-09 | Optical head |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2221563B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0640932A1 (en) * | 1993-08-25 | 1995-03-01 | Canon Kabushiki Kaisha | Information recording and/or reproducing apparatus and optical recording medium |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1073875A (en) * | 1964-12-16 | 1967-06-28 | Ibm | A system for cyclically generating a control signal for controlling the operation of a positionable mechanism |
| GB1573563A (en) * | 1976-03-25 | 1980-08-28 | Blazevic M | Means for rocording and reproducing sounds and displaying an associated written test |
| GB2055503A (en) * | 1979-07-30 | 1981-03-04 | Atlantic Richfield Co | Information carrier |
| GB2092791A (en) * | 1981-02-02 | 1982-08-18 | Smiths Industries Plc | Record carriers |
| EP0077641A2 (en) * | 1981-10-15 | 1983-04-27 | BURROUGHS CORPORATION (a Delaware corporation) | Method for improved focusing control in an optical memory system |
| WO1984002221A1 (en) * | 1982-11-30 | 1984-06-07 | George Saint | Data storage devices |
| WO1984004990A1 (en) * | 1983-06-07 | 1984-12-20 | Storage Technology Partners | A system and method for organizing and managing data stored on an informational disk |
| WO1985001818A1 (en) * | 1983-10-12 | 1985-04-25 | Drexler Technology Corporation | Quad density optical data system |
| GB2161632A (en) * | 1984-07-09 | 1986-01-15 | Drexler Tech | Scanning optical card reader |
| GB2171551A (en) * | 1984-12-31 | 1986-08-28 | Canon Kk | Reversing transducer or record movement in recording/reproducing apparatus |
| GB2174530A (en) * | 1985-03-29 | 1986-11-05 | Canon Kk | Optical record medium (card) recording/reproduction |
-
1989
- 1989-10-09 GB GB8922654A patent/GB2221563B/en not_active Expired - Lifetime
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1073875A (en) * | 1964-12-16 | 1967-06-28 | Ibm | A system for cyclically generating a control signal for controlling the operation of a positionable mechanism |
| GB1573563A (en) * | 1976-03-25 | 1980-08-28 | Blazevic M | Means for rocording and reproducing sounds and displaying an associated written test |
| GB2055503A (en) * | 1979-07-30 | 1981-03-04 | Atlantic Richfield Co | Information carrier |
| GB2092791A (en) * | 1981-02-02 | 1982-08-18 | Smiths Industries Plc | Record carriers |
| EP0077641A2 (en) * | 1981-10-15 | 1983-04-27 | BURROUGHS CORPORATION (a Delaware corporation) | Method for improved focusing control in an optical memory system |
| WO1984002221A1 (en) * | 1982-11-30 | 1984-06-07 | George Saint | Data storage devices |
| WO1984004990A1 (en) * | 1983-06-07 | 1984-12-20 | Storage Technology Partners | A system and method for organizing and managing data stored on an informational disk |
| WO1985001818A1 (en) * | 1983-10-12 | 1985-04-25 | Drexler Technology Corporation | Quad density optical data system |
| GB2161632A (en) * | 1984-07-09 | 1986-01-15 | Drexler Tech | Scanning optical card reader |
| GB2171551A (en) * | 1984-12-31 | 1986-08-28 | Canon Kk | Reversing transducer or record movement in recording/reproducing apparatus |
| GB2174530A (en) * | 1985-03-29 | 1986-11-05 | Canon Kk | Optical record medium (card) recording/reproduction |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0640932A1 (en) * | 1993-08-25 | 1995-03-01 | Canon Kabushiki Kaisha | Information recording and/or reproducing apparatus and optical recording medium |
| US5638345A (en) * | 1993-08-25 | 1997-06-10 | Canon Kabushiki Kaisha | Information recording and/or reproducing apparatus and method for use with a multi-track optical recording medium |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8922654D0 (en) | 1989-11-22 |
| GB2221563B (en) | 1990-06-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Effective date: 20060403 |