JPH051530B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention sets a large number of data tracks in an optical recording area, and changes optical properties corresponding to digital information to be written on the tracks. The present invention relates to an optical recording medium in which data is written by forming a pattern.

[Prior Art] In recent years, as an alternative to conventional magnetic recording media,
2. Description of the Related Art Optical recording media in which data is written by forming a pattern of changes in optical properties corresponding to digital information to be written, for example, a pattern of brightness and darkness, are being developed. This optical recording medium is characterized by being capable of high-density, large-capacity recording. If high-density, large-capacity information becomes possible, information that was conventionally stored on magnetic tapes, magnetic disks, etc., can be stored on a recording medium as large as a conventional magnetic disk card.

By the way, in the development of recording media, it is necessary to popularize them, so it is necessary that writing/reading devices, especially reading devices, be constructed at low cost.

Conventionally, practical optical recording medium reading devices have already been developed for disk-type media. For example, a light beam such as a laser beam follows a spiral track similar to the track on a record, and the reflected light from the track is detected by a reading sensor to read the written data. There is something.

However, this method cannot be applied to media that is not suitable for writing and reading data by rotating the media, such as card-shaped optical recording media in which data tracks are arranged linearly. There are problems with this, and its practical application has been delayed.

That is, in a non-rotating recording medium such as a card-shaped optical recording medium, data is recorded by setting a large number of data tracks in a rectangular recording area, and recording digital information to be written on the tracks. This is done by forming an optical bright and dark pattern corresponding to the data and writing the data. Therefore, when writing or reading data, the writing/reading head is
Must be controlled to move in the direction. Therefore, 1
Writing and reading data using a spot light beam requires the writing/reading head to be constantly moved in the X-Y directions, which poses a problem in that the moving mechanism and control mechanism for this purpose become complex.

On the other hand, it is conceivable to use a linear or planar reading element such as a CCD linear sensor. According to this type of linear sensor, data from one to several tracks can be read at one time over a certain range. Therefore, less mechanical movement of the sensor is required. However, this has the following problems.

[Problems to be Solved by the Invention] When reading data from a high-density, large-capacity recording medium using a CCD linear sensor, even a slight positional shift or angular displacement causes a reading error. Therefore, the reading device needs to detect the positional shift or angular shift, stop reading the data, and automatically correct the card position based on an instruction to reinstall the card or a detection signal.

However, in order to detect and correct this slight positional deviation, angular shift, etc. using a sensor, a complex and highly accurate detection mechanism and control mechanism are required. Although this is technically possible, the device becomes expensive and becomes an obstacle to popularizing the reading device.

The present invention was made to solve these problems, and it is possible to provide a positioning standard on the recording medium itself, and to detect positional and angular deviations using the reading sensor of the reading device. It is an object of the present invention to provide an optical recording medium that does not require a special detection mechanism and whose reading device can be constructed at low cost.

[Means for Solving the Problems] The present invention sets a large number of data tracks in an optical recording area, and forms a pattern of changes in optical properties on the tracks corresponding to digital information to be recorded. It is applied to an optical recording medium in which data is written using a method, and is characterized by having the following structural requirements as a means for solving the problem.

First, a strip-shaped reference line is provided in the optical recording area, and the area sandwiched between the reference lines is defined as a data recording area, and a large number of data lines perpendicular to the reference line are provided in the data recording area. Set track.

Second, a basic pattern is formed in which the width of the reference line is sequentially changed along the longitudinal direction from widening to narrowing or from narrow to wide at a certain period. to form.

Next, the above configuration requirements will be explained in more detail.

The optical recording area is an area in the optical recording medium where recording is actually performed, and is made of a material that can record data by forming a pattern of changes in optical properties by various means. For example, data may be recorded by physically or chemically changing the surface condition and changing the reflectance to form a bright and dark pattern.

The reference line is not a line segment in a geometric sense, but a band-shaped region having a width.

This reference line is formed by stringing together a basic pattern whose width sequentially changes in one direction along the longitudinal direction in the form of a band. Examples of basic patterns include an isosceles trapezoid, an isosceles triangle, and a right triangle. Of course, the pattern is not limited to a linear change, but may be a curved pattern.

An example of the form of the reference line formed by connecting these basic patterns is one in which the sides change in a sawtooth shape.

The pitch of the reference line can be set as appropriate depending on the length of the data track.

The distribution of changes in optical point properties in the width direction of the reference line is
The pattern of change in optical properties is made different from that used for recording the above data. Therefore, when using, for example, optical brightness and darkness as a change in optical properties, when bright and dark states in the data appear at a constant rate regardless of their contents, the reference line Any state of darkness is
What is necessary is just to form it so that it may be continuous with a certain width.

[Function] In the above configuration, by providing a band-shaped reference line in the optical recording area and defining the area between the reference lines as the data recording area, the data area can be easily distinguished from other areas. In addition, the reference line can be used as a guideline for movement of a linear or planar sensor such as a CCD linear sensor.

Furthermore, by setting a large number of data tracks in the data recording area in a direction perpendicular to the center line of the reference line, one or several tracks can be recorded using a linear or planar sensor such as a CCD linear sensor. data can be read at once. At this time, by also reading the reference line with a linear or planar sensor such as a CCD linear sensor, it is possible to easily detect a positional deviation or angular deviation between the sensor and the recording area.

In other words, data is read using a reading sensor such as a CCD linear sensor, with the two reference lines and the data track between them in view, and the positions of the two reference lines are read from the read data. ,
By treating the data in between as the data to be read, even if the reading sensor is misaligned in the track direction, the data can be read easily and accurately without making difficult mechanical position corrections.

On the other hand, the reference line is formed by arranging basic patterns in which the width is sequentially changed from wide to narrow or from narrow to wide at a constant cycle along the longitudinal direction. Therefore, by utilizing this property, it is possible to detect whether or not there is an inclination between the reading sensor and the track.

That is, as mentioned above, from the read data,
When the positions of the two reference lines are read, the inclination can be detected by comparing their widths. If there is no inclination between the reading sensor and the track, the widths of the reference lines that sandwich the track are equal, and on the other hand,
If there is a slope, the width of the reference line will vary. In this case, since the width of the basic pattern changes in one direction, from wide to narrow or from narrow to wide, the angle and direction of the inclination can be detected based on the magnitude of the difference and the sign of the difference. I can do it.

As described above, according to the present invention, when reading data from one data recording area, there is no need to move the reading head in the track direction. All you have to do is move in parallel along the line. Therefore, the head moving mechanism can be easily constructed, and a special sensor for positioning is not required. Furthermore, the inclination can be easily and accurately detected using a reading sensor without requiring a special sensor.

[Example] An example of the present invention will be described with reference to the drawings.

The following example is applied to a card-type optical recording medium. In particular, this is an example of an optical recording medium in which a difference in reflectance is adopted as a change in optical properties, and data is read based on the high or low reflectance. be.

<Configuration of Example> The optical recording medium of the example shown in FIG. 1 has, for example,
On a plastic board 1 about the size of a business card,
An optical recording area 2 is provided, and this optical recording area 2
It is constructed by providing a plurality of reference lines 5 at regular intervals in the longitudinal direction.

The optical recording area 2 can be formed by locally changing optical properties such as reflectance (in this example, reflectance) by irradiating a light beam such as a laser beam or by using photographic technology. It is made of a material on which binary coded information can be written as a light and dark pattern. Examples include a material that is locally melted by a light beam to change its reflectance, a photosensitive material, and the like.
This optical recording area 2 may be formed directly on the substrate 1, or may be formed in the form of a film and may be attached.

As shown in FIG. 2, each reference line 5 is formed into a band shape by periodically connecting a predetermined basic pattern 5a whose width changes sequentially. In this embodiment, an isosceles trapezoid is used as the basic pattern 5a. Although other forms are possible, an isosceles trapezoid has a constant width even at its narrowest point, making it easier to distinguish it from data on a track, as well as the amount of change when detecting inclination. has the advantage of being larger.

The reference line 5 in this embodiment includes a large number of basic patterns 5.
a are aligned in the same direction (in this example, the width on the left side is wide and the width on the right side is narrow), and by overlapping their parallel sides, they are connected linearly to form a band shape. be. That is, both sides 5b and 5c of each reference line 5 form a periodic change like a sawtooth wave.

Further, each of the reference lines 5 is arranged so as to be symmetrical with respect to the center line of the data recording area sandwiched therebetween. Further, the arrangement pitch of each reference line 5 is appropriately set according to the width of the data recording area, but in this embodiment, it is set equally.

This reference line 5 may be formed at the same time as data writing, or may be formed in advance, separately from data writing. The formation can be performed by various methods depending on the material of the optical recording area 2, etc. For example, when forming the optical recording area 2, it can be formed together with data or alone using photographic technology, printing technology, etc. It is also possible to irradiate the optical recording area 2 with a laser beam to write in a band shape.

The area between each reference line 5 becomes the data recording area 3. In this data recording area 3, a large number of data tracks 4 are set in a direction perpendicular to the reference line 5. This data track 4 consists of a large number of recording cells (not shown) that constitute the minimum unit of a bright/dark pattern. Data is recorded by this recording cell.

In the simplest way, one recording cell represents one bit, but in this embodiment, since the data is binary encoded using the FM encoding method, consecutive recording cells Two bits represent one bit of data. That is, as shown in the waveform diagram of FIG. 3, when two consecutive recording cells are "0, 0" or "1, 1", it represents data "0".
On the other hand, when two consecutive recording cells are "0, 1" or "1, 0", it represents data "1".

Each reference line 5 has a structure in which the width L of the narrowest part is sufficiently longer than the length of one bit of data, and the reflectance pattern in the width direction can be clearly distinguished from the reflectance pattern of the data. It's summery.

<Operation of the embodiment> The operation of the embodiment configured as described above will be explained, focusing on the operation of reading data written in the recording area.

In this embodiment, the reading sensor is, for example,
Uses a CCD linear sensor. This reading sensor is
A field of view is a range longer than the width of the data recording area of the optical recording medium, and a photodetector for detection is arranged facing the field of view. This photodetector is 1
The number of elements, which is twice the number of cells, for example, 1024 elements in this embodiment, are arranged at intervals corresponding to each recording cell of the track.

First, in order to read data from an optical recording medium, a movement control device (not shown) causes a reading sensor to face a track in the data recording area 3 from which data is to be read. At this position, the reading sensor starts the reading operation. The reading sensor serially transfers the charges accumulated in each photodetector in response to a synchronization signal sent from a synchronization signal generation circuit (not shown) and outputs it as a video signal.

After reading the data of one track in this way, the reading sensor is sent to the next track by the movement control device and reads the data by the same operation as described above.

The reading sensor moves along the data recording area 3 on the optical recording medium 2 and reads data one band at a time. The range of the field of view F that the reading sensor can capture at one time is approximately the width of two data recording areas 3, as shown in FIG. In this case, it is standard that the two reference lines 5 are always placed within the field of view F.

By the way, in order for a reading sensor to read data correctly, the sensor must be accurately facing the data track to be read. In this embodiment, data on both the upper and lower reference lines are extracted from the data read by the reading sensor, and by comparing their widths, it is detected whether the sensor is accurately facing the data track to be read. can do.

For example, the reading trajectory indicated by the arrow in FIG. 5 is a case where the reading sensor is exactly facing the data track to be read. In this case, the widths of the upper and lower reference lines 5 are equal. Therefore,
The data widths of both the upper and lower reference lines read by the reading sensor become equal.

Further, the reading locus indicated by the arrow in the same figure is a case where the reading sensor is not accurately facing the data track to be read. In these cases, the widths of the upper and lower reference lines 5 are different. That is,
In the case of an arrow, it is wide at the top and narrow at the bottom. On the other hand, in the case of an arrow, the opposite is true.

This aspect is uniquely determined within this range because the width of the reference line sequentially changes in one direction from wide to narrow from left to right in the longitudinal direction within the basic pattern of the reference line.

Note that there is a possibility that the connection portion of the basic pattern is not uniquely defined. However, since this is about a fraction of the number of readings for one basic pattern, for example, the results of comparing the widths of the reference lines obtained from multiple readings for the basic pattern can be temporarily saved, and from these results, majority decisions etc. can be made. By selecting according to the means, the aspect of inclination can be detected without error.

The distinction between the reading trajectories indicated by the arrows in the figure can be detected by determining the difference in width between the data of the upper and lower reference lines read by the reading sensor. In other words, by using the data of either the upper or lower reference line as a reference and subtracting the data of the other reference line, the magnitude of the difference determines the degree of inclination, and the sign determines the direction of inclination. .

On the other hand, the relative shift in the vertical direction of the field of view of the reading sensor with respect to the data recording area can be detected by reading the position of at least one of the two reference lines in the field of view of the reading sensor from among the read data. becomes possible. As long as the two reference lines are included in the field of view, it is sufficient to extract the read data between the two reference lines as normal data, and there is no need to correct the relative deviation in the vertical direction.

Therefore, even if the field of view F of the reading sensor is slightly shifted up or down (in the track direction), it is possible to read the data accurately without making minute and complicated positional corrections.

<Modifications of Embodiments> In the above embodiments, an isosceles trapezoid is used as the basic pattern, but other shapes may also be used. For example, it may be an isosceles triangle, a right triangle, a trapezoid in which one side is at a right angle to two parallel sides, or the like. Furthermore, the portion where the width changes from wide to narrow may not be linear, but may be a curved line such as an S-shaped curve.

Further, in the above embodiments, an example of a card-type optical recording medium is shown, but the present invention is not limited to this, and the medium may be in a sheet-like or tape-like form.

Furthermore, in the above embodiments, data is recorded based on the difference in reflectance, but the invention is not limited to this, and changes in optical properties such as transmittance, polarization, etc. can also be used.

[Effects of the Invention] As explained above, the present invention provides a positioning standard on the recording medium itself, and can detect positional and angular deviations using the reading sensor of the reading device, and has a specially designed complex and highly accurate detection mechanism. There is an effect that the reading device can be constructed at low cost without the need for this.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the optical recording medium of the present invention, FIG. 2 is an enlarged plan view of the main part thereof, FIG. 3 is a waveform diagram showing the reflectance pattern of data in the above embodiment, and FIG. 4 5 is an explanatory diagram showing the relationship between the field of view of the reading sensor and the data recording area, and FIG. 5 is an explanatory diagram showing the aspect of the inclination between the field of view of the reading sensor and the data recording area. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Optical recording area, 3... Data recording area, 4... Track, 5... Reference line,
5a...Basic pattern.

Claims (1)

[Claims] 1. A format in which a large number of data tracks are set in an optical recording area, and data is written on the tracks by forming a pattern of changes in optical properties corresponding to digital information to be recorded. In the optical recording medium, strip-shaped reference lines are provided in the optical recording area, and an area between the reference lines is defined as a data recording area, and a large number of strip-shaped reference lines are provided in the data recording area perpendicular to the reference lines. A basic pattern in which a data track is set, and the width of the reference line is sequentially changed from wide to narrow or from narrow to wide at a constant cycle along the longitudinal direction. An optical storage medium characterized in that it is formed by arranging .