JPH053660B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is provided in a reading device for reading data from an optical recording medium having a data recording area divided by a strip-shaped reference line having a constant width. The present invention relates to a reference line detection device that detects the reference line from read data.

〓Conventional technology〓 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. There are two types of devices of this kind: disk-type disks having spiral tracks, and card- or sheet-type disks having a rectangular or band-shaped optical recording area with a large number of data tracks.

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 formats that are not suitable for writing and reading data by rotating the medium, such as card-shaped optical recording media in which data tracks are arranged linearly. has problems, 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 using a sensor, a complex and highly accurate detection mechanism and control mechanism are required. this is,
Although it is technically possible, the device becomes expensive and becomes an obstacle to widespread use of reading devices.

The present invention has been made to solve these problems, and in response to providing a reference line for positioning on the optical recording medium side, a reference line detection means is provided on the reading device side, and a predetermined positioning reference line is provided on the reading device side. Data can be accurately read by a reading sensor without problems with range positional or angular deviation, and the reading device can be configured at low cost without the need for a complex and highly accurate detection mechanism and control mechanism. An object of the present invention is to provide a reference line detection device for an optical recording medium that can be used.

<Means for Solving the Problems> The present invention provides a method for reading data from an optical recording medium in which a data recording area is partitioned by strip-shaped reference lines having a constant width. A reference line detection device is provided in a reading device that reads data with the data recording area and a reference line sandwiching the area in view, and detects the reference line from the read data, and solves the problem. The means is characterized by having the following configuration requirements.

First, a signal level discriminator is provided for extracting a signal at a level corresponding to the optical properties of the reference line from among the output signals from the reading sensor.

Second, a duration measuring means is provided for measuring the duration of the extracted signal.

Thirdly, the apparatus includes determining means for comparing whether or not the duration measured by the duration measuring means reaches a preset reference value, and outputting a reference line detection signal when the duration reaches the reference value.

〓Operation〓 The reading device to which the present invention is applied is equipped with a linear or planar sensor such as a CCD linear sensor, and can read data of one or several tracks at once. At that time, the reference line is also read using a linear or planar sensor such as a CCD linear sensor.

The read data is sent to the signal level discrimination means, which is the first component. Here, a signal at a level (for example, low level) corresponding to the optical properties of the reference line is extracted from the data.
Signal extraction is gate-controlled by a clock signal synchronized with the output signal from the reading sensor using an AND gate circuit, for example, to discriminate between signals at a level corresponding to the optical properties of the reference line and other levels. Do by doing.

The second component is the duration measurement means.
The time period during which the level of the extracted signal continues is measured. This measurement is performed, for example, by using a counter or the like to count an appropriate clock signal using the extracted signal as an enable signal.

The determining means, which is the third component, compares the measured value measured by the duration measuring means with a preset reference value, and when the measured value reaches the reference value, outputs a reference line detection signal. Output.

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

The following examples are based on a card-type optical recording medium that uses a difference in reflectance as a change in optical properties.
This is provided in a reading device that reads data based on the level of reflectance. Therefore, prior to explaining the structure of the embodiment, the structure of the optical recording medium will be explained with reference to the drawings.

<Structure of Optical Recording Medium> The optical recording medium shown in FIG. 2 has, for example, an optical recording area 2 provided on a plastic substrate 1 about the size of a business card. , a plurality of reference lines 5 are provided at constant intervals.

The optical recording area 2 can be formed by locally changing optical properties such as reflectance (reflectance in this embodiment) by, for example, 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.

Each reference line 5 is formed into a band shape with a constant width, and the width and interval are determined as described below.
It is formed by holding it at a preset value. Also,
In this embodiment, they are formed continuously in the longitudinal direction.

The reference line 5 may be formed at the same time as the data is written, or may be formed in advance separately from the 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 6 that constitute the minimum unit of a bright and dark pattern. Data is recorded by this recording cell 6.

In the simplest case, one recording cell represents one bit, but in this embodiment, since the data is binary encoded using the FM encoding method, continuous recording is performed using the recording cell 6. The configuration is such that two cells represent one bit of data. That is, as shown on the right side of the waveform in 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 width L that is sufficiently longer than the length of 1 bit of data, and as shown in FIGS. 3 and 4, the reflectance pattern in the width direction is distinct from the reflectance pattern of the data. It has a structure that can be easily identified. That is, both sides 5a and 5c in the width direction have a width corresponding to one bit of a recording cell used for recording data, and are set to have a high reflectance.
On the other hand, the widthwise intermediate portion 5b is set to have a bit width several times the number of recording cells (2 bits in this embodiment) required to represent one digital bit of data, and to have a low reflectance.

<Configuration of Embodiment> The configuration of an embodiment of the reference line detection device of the present invention will be described with reference to FIG. The reference line detection device of this embodiment shown in the figure is configured as a part of a reading device that reads data recorded on an optical recording medium.

The optical recording medium reading device shown in FIG. 3 includes a reading sensor 10 that reads data by following the track 4 in the data recording area 3 shown in FIG. A binarization circuit 20, a buffer 30 for temporarily storing the binarized signal Bs, a reference line detection means 40 for detecting the reference line 5 from the binarized signal Bs, and a synchronization signal generation circuit 50. It is prepared and configured as the main part. In addition to the main parts mentioned above, the optical recording medium reading device includes a movement control device, a light source, an output data processing device, etc. (none of which are shown), but these are not directly related to the configuration and operation of this embodiment. Therefore, the explanation will be omitted.

The reading sensor 10 is composed of, for example, a CCD linear sensor, and has a detection photodetector arranged in a range longer than the width of the data recording area 3 of the optical recording medium. This photodetector has two times as many elements as the number of cells, for example, 1024 elements in this embodiment, arranged at intervals corresponding to each recording cell 6 of one track.

Reading by the reading sensor 10 is performed by serially outputting charges accumulated in proportion to the amount of light received by each photodetector in accordance with a synchronizing signal R. Its output becomes a video signal Vd for each track.

The binarization circuit 20 is a comparator that compares the video signal Vd with a certain threshold, sets a part of the waveform larger than the threshold to a high level, sets a part smaller than the threshold to a low level, converts it into a binarized signal Bs, and outputs it. It is composed of:

The buffer 30 includes an input/output control gate and a register, and is configured to receive a reference line detection signal, which will be described later.
The control gates on the input side and the output side are alternately opened and closed according to the input of Ls, and the binary signal Bs is stored and the stored binary signal Bs is output.

The reference line detection means 40 includes the binarization circuit 2
An AND gate circuit 41 for sampling the high level portion of the binary signal Bs outputted from 0 in synchronization with the synchronizing signal 〓R is provided as a signal level discrimination means, and is reset by the output of the AND gate circuit 41 and , a counter 42 for counting the synchronization signal 〓R is provided as a duration measuring means,
Further, the comparator 43 is provided as a determination means, which compares the counted value output from the counter 42 with a preset time width and outputs a reference line detection signal Ls when the counted value is larger than the set time width. be done.

This set time width value is set by converting the width of the reference line to be detected into the number of synchronization signals R, which corresponds to the time required for reading by the reading sensor 10. In this embodiment, pulse 4 of the synchronization signal 〓R
It is set to 0. This value is set almost fixedly.

The synchronizing signal generating circuit 50 is composed of an oscillator, a frequency divider, etc., and supplies a synchronizing signal 〓R to the reading sensor 10, the AND gate circuit 41, and the counter 42.

<Operation of the embodiment> The operation of the embodiment in the reading device configured as described above will be explained.

First, in order to read data from an optical recording medium, a movement control device (not shown) causes the reading sensor 10 to face the track of the data recording area 3 from which data is to be read. At this position, the reading operation of the reading sensor 10 is started. Reading sensor 10
The charge accumulated in each photodetector is serially transferred by the synchronization signal R sent from the synchronization signal generation circuit 50, and outputted as a video signal Vd as shown in FIG. 5a. This video signal Vd is sent to a binarization circuit 20 and binarized.

After reading the data of one track in this way, the reading sensor 10 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 10 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 10 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.

Binarized signal output from the binarization circuit 20
Bs is the buffer 30 and the AND gate circuit 41
sent to.

The buffer 30 uses a reference line detection signal, which will be described later.
Ls causes the binarized signal Bs to be stored when the gate is open, and is prevented from being stored when the gate is closed.

On the other hand, in the AND gate circuit 41, the binary signal
A synchronizing signal 〓R is also input together with Bs. Therefore,
The AND gate circuit 41 outputs a pulse synchronized with the synchronizing signal R when the binary signal Bs is at a high level.

The counter 42 is reset by the output pulse from the AND gate circuit 41. This counter 42 counts the synchronizing signal R, and each time it is reset, it counts again. Therefore, in this counter 42, when the output of the binary signal Bs continues to be in a low level state,
The count value is cumulatively added, and in other cases,
It is reset in a short period of time and is not cumulatively added over a long period of time.

The comparator 43 compares the count value of the counter 42 with a preset time width. Now, if the count value reaches this time width setting value, the comparator 4
3 outputs the reference line detection signal Ls at that point. As shown in FIG. 5b, the reference line detection signal Ls falls at the time when the video signal Vd rises from a continuous low level region to a high level region.

This reference line detection signal Ls is the buffer 30
sent to. In the buffer 30, the first reference line detection signal Ls opens the input gate and closes the output gate.

Thereafter, as shown in FIG. 5a, in a region where high and low patterns alternately appear at short time intervals, the counter 42 is constantly reset, so that the counted value does not reach the time width setting value.

Then, when the second low level continuation region is reached, the count value of the counter 42 reaches the time width setting value, and the reference line detection signal Ls is output, as described above.

This reference line detection signal Ls is the buffer 30
sent to. In the buffer 30, the input gate is closed and the output gate is opened by this second reference line detection signal Ls.

This allows only data from the track to be read from the output of the reading sensor 10, which includes two reference lines, data on tracks sandwiched between them, and part of data on tracks outside the two reference lines. can be taken out. Therefore, even if the field of view F of the reading sensor 10 is slightly shifted vertically (in the track direction),
Data can be read accurately without making minute and complicated positional corrections.

Further, in order to correct a large positional deviation that is out of the field of view of the reading sensor 10, a highly accurate and complicated detection mechanism or control mechanism is not required.

Furthermore, it is also possible to detect positional deviation and angular displacement of the reading head based on the time width from the start of reading the video signal to the position of the reference line.

<Modification of Example> In the above example, the case where the width direction reflectance pattern of the reference line is configured as "100...001" is shown, but it is not limited to this, and other patterns may be used. . For example, it may be "011...110". In this case, the AND gate circuit 41 may be configured to invert the phase of the video signal and input it.

Further, in the above embodiment, the signal level discrimination means,
Although the duration measuring means and the determining means are constituted by an AND gate circuit, a counter, and a comparator, these are merely examples, and they may be constituted by other circuits having similar functions.

<Effects of the Invention> As explained above, in accordance with the provision of a positioning reference line on the optical recording medium side, the present invention provides the reference line detection means on the reading device side to detect the field of view of the reading sensor. A complex and highly accurate detection mechanism and control mechanism that allows the reading sensor to accurately read data without having to worry about minute positional or angular deviations within the range and without making minute and complicated positional corrections. This has the advantage that the reading device can be constructed at low cost without the need for special components.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an example of a reading device equipped with an embodiment of the reference line detection device of the present invention, and FIG. 2 is a plan view showing an example of an optical recording medium to be read by applying the present invention. Fig. 3 is an enlarged plan view of the main part, Fig. 4 is a waveform diagram showing the reference line and data reflectance pattern of the optical recording medium, and Fig. 5 is a waveform diagram showing the reference line of the optical recording medium and the data reflectance pattern. A waveform diagram showing the relationship, and FIG. 6 is an explanatory diagram showing the relationship 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,
6...recording cell, 10...reading sensor, 20...
Binarization circuit, 30... buffer, 40... reference line detection means, 41... and gate circuit, 42...
Counter, 43... comparator, 50... synchronous signal generation circuit.

Claims (1)

[Scope of Claims] 1. When reading data from an optical recording medium in which a data recording area is provided by dividing it by a strip-shaped reference line having a constant width, a reference that sandwiches the data recording area and the area in the field of view of a reading sensor. The reference line detection device is provided with a reading device that reads data in anticipation of the reference line, and detects the reference line from the read data, a signal level discrimination means for extracting a signal of a level corresponding to the property; a duration measuring means for measuring the duration of the extracted signal; and a duration measuring means for measuring the duration of the extracted signal; and a preset reference value for the duration measured by the duration measuring means. 1. A reference line detection device for an optical recording medium, comprising: determination means for comparing whether or not a reference value is reached, and outputting a reference line detection signal when the reference value is reached.