JPH0685219B2 - Optical digital data read control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical digital data read control method, and more particularly to an optical digital data read control method using an optical read head having a plurality of one-dimensionally arranged read elements. Regarding

[Technical background of the invention and its problems]

At present, magnetic cards such as cash cards and credit cards are widely used, but in recent years, optical data recording cards for optically recording information have been proposed in order to improve recording density and ensure recording reliability. . FIG. 3 shows an example of a conventionally proposed optical data recording card. Recording card 1
A data recording section 2 is provided on the upper side, and a plurality of data recording areas 3 are formed in a stripe shape on the data recording section 2. FIG. 3A shows an example in which the data recording area 3 is formed vertically, and FIG. 3B shows an example in which the data recording area 3 is formed horizontally. Data is optically recorded and read in each data recording area.

To read data, a CCD line sensor or the like is generally used as a read head and is scanned on each data recording area. For example, in the card shown in FIG. 3 (a), the reading head is vertically scanned along one data recording area 3 to perform reading, and in the card shown in FIG. 3 (b), scanning is similarly performed left and right. Will be read. Therefore, if the read head is tilted during the read scan, accurate reading cannot be performed. In particular, since the optical data recording card has a higher recording density than the magnetic card, it is necessary to control the inclination of the reading head with high accuracy in order to perform accurate reading. However, in the conventional data recording method, since no information about the tilt of the read head can be obtained from the read data, the tilt of the read head cannot be controlled with high accuracy.

[Object of the Invention]

Therefore, it is an object of the present invention to provide a method for controlling the reading of optical digital data, which can control the tilt of the reading head with high accuracy.

[Outline of Invention]

A feature of the present invention is that data is recorded in pits by scanning an optical read head having a plurality of read elements arranged one-dimensionally in the X direction in the Y direction perpendicular to the X direction. In a control method for reading optical digital data from a card-shaped optical recording medium, the recording medium comprises:
A plurality of bars having different lengths and elongated in the Y direction,
At least two auxiliary marks, which are arranged in the X direction in the order of their length, are provided in the X direction.
The inclination of the read head with respect to the recording medium in the Y direction is detected based on the difference in the number of peaks in the read signals for the two auxiliary marks, and the attitude of the read head with respect to the recording medium is corrected based on the detection result. In this way, the tilt of the read head can be controlled with high accuracy.

Example of Invention

The present invention will be described below based on the embodiments shown in FIGS. 1 and 2. FIG. 1 is an explanatory view showing a state in which data is recorded in the data recording area 3 of the card shown in FIG. 3 (a) by the method according to the present invention. Each area surrounded by a broken line in this figure represents one data recording area. The dashed line in the figure shows the position of the optical read head 4. For the read head 4, for example, a CCD line sensor or the like is used. The left and right positioning of the reading head 4 is performed by reading the positions of the two bars P provided on the left side of each area. That is, the position control is performed so that the two bars P are always at the left end of the read head 4. The two bars P are formed as a continuous line from the top to the bottom in one area (the central portion is partially omitted in the figure), and the read head 4 is arranged along the bar P from the top to the bottom. One area will be scanned. The position of the read head 4 shown in FIG. 1 is the position when the area 3-1 is read, but a part of the right side portion of the read head 4 lies in the adjacent area 3-2.

The actual data is recorded in the area Q adjacent to the right of the bar P. In the case of this embodiment, the area Q is further divided into A, B, C, B ',
It is classified into five areas of A '. Here, address data indicating the address of each data recording area is recorded in the areas A and A ', and auxiliary marks used for tilt correction of the read head 4, which is a feature of the present invention, are recorded in the areas B and B'. Area C
The original data to be recorded is recorded in (partially omitted in the figure).

The read head 4 has a plurality of read elements arranged one-dimensionally in the X direction in the figure. In the area C, data to be recorded is arranged in pits. The pits are elongated in the Y direction (length 1), and one row arranged in the X direction is one unit, and a plurality of these rows are arranged in the Y direction. The reading head 4 reads the pits in a row unit. Therefore, as pointed out in the above-mentioned problem, when the read head 4 is tilted while being deviated from the X direction, when the tilt angle exceeds a certain value, 2
The pits will be read over two rows, making accurate reading impossible.

In order to correct this inclination, as shown in FIG.
An auxiliary mark is provided on B '. FIG. 2 is an explanatory diagram of this auxiliary mark.

The reading head 4 is scanned in the Y direction of the drawing using the bar P as a guide to read the auxiliary mark. The auxiliary mark is composed of four bars of different lengths a, b, c and d. Each bar is elongated in the Y direction and arranged in the X direction in the order of length. The difference in length between adjacent bars is preferably equal to the length 1 in the Y direction of the data pits arranged in the area C in FIG. An auxiliary mark composed of such four bars a, b, c, d is provided for each data recording area, and the read head 4
The auxiliary marks in the two data recording areas adjacent to each other are read at the same time. That is, in FIG. 2, auxiliary marks M1 and M2
Although they belong to different data recording areas, they are read simultaneously. In this embodiment, such a pair of auxiliary marks are arranged in two stages. That is, the auxiliary marks M1, M2
And a pair of auxiliary marks M1 'and M2'. The two stages are provided in order to ensure the reading, and the number of stages may be one, or more stages may be provided.

In FIG. 2, line segments S, R, and L respectively indicate reading lines when the read head 4 is normally scanned, tilted to the right, and tilted to the left. When the reading head 4 passes over the auxiliary mark during normal scanning, the read signal becomes, for example, the signal SS. The letter attached to each peak indicates the corresponding bar when read. The number of peaks of the read signal is equal on the left and right, and it can be determined that normal scanning is performed. When the read head 4 is tilted to the right, that is, when the auxiliary mark is read at the position indicated by the line segment R, the read signal becomes the signal RS. The number of peaks of the read signal is greater on the right side than on the left side, and it can be determined that the read signal is tilted to the right. Therefore, the reading head 4 can be corrected by performing an operation of tilting it to the left. Conversely, when the read head 4 is tilted to the left, that is, when the auxiliary mark is read at the position indicated by the line segment L, the read signal is a signal.
It becomes like LS. The number of peaks of the read signal is larger on the left than on the right, and it can be determined that the read signal is tilted to the left. Therefore, the read head 4 can be corrected by performing an operation of tilting it to the right.

In this way, by detecting the read signal when the read head 4 scans the auxiliary mark, the tilt of the read head 4 can be known, and control to eliminate this tilt becomes possible. Although two auxiliary marks provided in adjacent data recording areas are used as a pair in this embodiment, a pair of auxiliary marks may be provided in the same data recording area and used. However, it is preferable to keep the distance between both auxiliary marks as wide as possible in order to ensure a certain degree of accuracy.

〔The invention's effect〕

As described above, according to the present invention, in recording optical digital data, at least two auxiliary marks composed of a plurality of bars having different lengths are provided to detect the tilt of the read head. It can be controlled with high precision.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a data recording state of a recording card used in the optical digital data reading control method according to the present invention, FIG. 2 is an explanatory diagram of an auxiliary mark used in the present invention, and FIG. It is a figure which shows an example of the recording card of typical optical data. 1 ... Recording card, 2 ... Data recording area, 3 ... Data recording area, 4 ... Read head, P ... Positioning bar, Q ... Data area, A, A '... Address data area, B , B '... tilt correction area, C ... data area to be originally recorded, M1, M2, M1', M2 '... auxiliary mark, S, R, L ...
… Read head position, SS, RS, LS… Read signal.

Claims (2)

[Claims] 1. A card in which data is recorded in pits by scanning an optical read head having a plurality of read elements arranged one-dimensionally in the X direction in a Y direction perpendicular to the X direction. In a method for controlling reading of optical digital data from a linear optical recording medium, an auxiliary mark formed by arranging a plurality of bars having different lengths and elongated in the Y direction in the X direction is arranged on the recording medium. , At least two in the X direction are provided, and the inclination of the read head with respect to the recording medium in the Y direction is detected based on the difference in the number of peaks in the read signals for the at least two auxiliary marks. An optical digital data read control method comprising: correcting the attitude of the read head with respect to the recording medium based on the above. 2. An auxiliary mark having a length difference between adjacent bars of a plurality of bars equal to the length of a pit for recording data in the Y direction is used. A method for controlling reading of optical digital data according to item 1.