JPS61166683A - Optical card reader - Google Patents

Abstract

PURPOSE:To read stably the correct recording information by scanning a photodetecting element by plural times per track to detect that the output of said element is higher than a prescribed level and extracting the output just for a scan period exceeding the prescribed level. CONSTITUTION:A photodetecting element 10 contains plural detection elements arrayed linearly, and the width of the scan period of a scan circuit 31 is controlled together with the card driving speed so that a single piece of tracks of an optical card is scanned several times. The analog signal given from an LPF34 is supplied to a peak holding circuit 41. The signal A is supplied to a 1-scan period delay circuit 43 via a comparator 42 for level detection together with the signal B. The delay signal C is supplied to a pulse generating circuit 44, and the output pulse D is supplied to gate 45. This gate 45 is opened just for a single scan period following the scan where the signal A reaches a man value. Then the data reproduced with stability by a data reproducing circuit 37 is supplied to a data processing circuit 38. In such a way, the correct recording information can be read with high stability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to each track of an optical card in which information signals are recorded on each of a plurality of parallel tracks so as to be optically readable by an array of optical recording traces. The present invention relates to an optical card reading device that optically reads information signals from a card.

[Conventional technology]

As a so-called memory card or software card, as shown in FIG. 4, a rectangular card (1) has a plurality of mutually parallel tracks T perpendicular to its reference end surface (1a), each of which As shown in FIG. 5, each track T has an information signal recorded thereon so as to be optically readable by an optical recording trace, for example, an array of pits P.

An optical card reading device that reads information signals recorded on each track T from such a card (1) is as follows:
As shown in Figs. 6 and 7, the card (11) inserted into the device is sent by the card feeding roller (2) in the direction of the arrow (3) along the reference end surface (1a) of the card (1). The light (5) from the illumination light source (4) such as a light emitting diode enters the trunk T of the card (1) via the condenser lens (6), and the reflected light from the truck T, i.e., the light from the truck T. The reading light (7) passes through the imaging lens (8
) is projected onto the photodetecting element aω held on the holding plate (9) and detected by the element αQ. The photodetection element α [is a CCD (charge-coupled device) line sensor in which a plurality of detection elements (10a) are arranged in a straight line, and the image projected thereon is read by electrical scanning. As shown in FIG. 8, the longitudinal direction of the track images coincides with the arrangement direction of the detection elements (10a) on the element α, and the images P of all the pits of one track are aligned.
' are simultaneously imaged on the element αω, and the information signals for one track are read out at once.

The electrical configuration of a conventional optical card reading device is, for example, as shown in FIG. Corresponding transfer elements (10t) are arranged with gates (Log) in between.

First, the gate (10g) is closed for a certain period (accumulation period), and charges generated by light are accumulated in each light receiving element (10r). Next, the gate (10g) was opened momentarily,
This accumulated charge corresponds to each transfer element (10
t), and the light receiving element (10r) starts to accumulate charges again. Each transfer element (10t)
The charges transferred to the scanning signal (31) from the scanning circuit (31)
readout clock) and read out as a serial signal during a fixed period (scanning period).

Note that since the accumulation period and the scanning period are the same time and timing, the term scanning period (scanning) will be used in the following description.

The readout signal, which is the output of the photodetection element (1G), is a discrete analog signal for each detection element (10a), and after being amplified to a predetermined level by the amplifier (32), it is sent to the sample hold circuit (33) and the low Range filter (34)
The signal is converted into a continuous analog signal and supplied to a comparator (35). The input signal to the comparator (35) is binarized by comparing whether the voltage is lower than the reference voltage, and the binarized read signal is P
The signal is supplied to the LL (36) and the data reproduction circuit (37).

In the PLL (36), a clock signal is extracted and recirculated, and this clock signal is supplied to a data reproducing circuit (37) to reproduce binary data. The reproduced binary data is supplied to the data processing circuit (38), and P L L (
-36) is processed as appropriate using the clock signal from.

[Problem that the invention seeks to solve]

As mentioned above, during reading, the optical card is fed in a direction perpendicular to the tracks, and the images of each track projected on the photodetecting elements are read out by electrical scanning.

\, as shown in Fig. 10, three pits P1. P2. Regarding P3, the amount of light incident on a specific photodetecting element corresponding to pits P1 to P3 changes periodically as shown in FIG. 11 in accordance with the feeding of the card. That is, the amount of incident light is the pit Px, P2
and time tct when the center of the projected image of P3 coincides with the center of the photodetection element.

It reaches its maximum at tG2 and tC3, and the middle part of each focus is projected onto the light detection element, in other words, the time t
ax and tc2, intermediate time tmi and time tC2 and tc3
The minimum value is reached at an intermediate point in time tIL2.

However, the scanning period of the trunk to which pit P2 belongs is
From time tm1 to tT112, which is the time between time tc2 when the photodetection output is the maximum and time tm1 when the photodetection output is the minimum, the readout signal obtained from the photodetection element includes a projection of the intermediate part between the adjacent track. There is a problem in that an invalid component due to the image is included, and the mantle trust of the pit-corresponding signal due to the projected image of the pit is degraded. In addition, the scanning timing may be shifted for some reason, and the scanning period may vary from tci to tC2.
Or when it becomes like tC2 to tc3, the information recorded on two tracks will be read out at the same time.
This is equivalent to a situation in which two trunks overlap, and there is a problem in that correct recorded information cannot be read out.

In view of the above, an object of the present invention is to provide an optical card reading device that can improve the contrast of a focus signal and stably read correct recorded information.

[Means for solving problems]

The present invention uses an optical card (1) on which an information signal is recorded in a plurality of parallel trunks T so as to be optically readable by an array of optical recording traces P, and a plurality of detection elements (10a) are arranged. The optical card (11) is arranged in a straight line and includes a photodetector element aω for detecting the reading light of the trunk T, and a scanning means (31) for electrically scanning the photodetector element a to obtain an output signal. In the optical card reading device, the scanning means (31) reads one of the tracks T.
A level detecting means (42) for setting the scanning period of the scanning means (31) so as to perform scanning multiple times, and detecting that the level of the output signal of the photodetecting element 0ω is equal to or higher than a predetermined value; a delay means (43) for delaying the output of the level detection means (42) by at least l scanning period of the scanning means (31) within the range of multiple scans in which the level of the output signal of the photodetection element aω exceeds a predetermined value; This delay means (
Extracting means (44) for extracting the output signal of the photodetecting element aah or a signal based thereon for one scanning period of the scanning means (31) based on the output of the photodetecting element aah (43).

(45) This is an optical card reading device characterized by providing the following.

[Effect]

According to the present invention, the information signal of the track is read during the scanning period in which the level detection means (42) obtains a signal exceeding a predetermined level.

〔Example〕

Hereinafter, an embodiment of the optical card reading device according to the present invention will be described with reference to Section 1 and FIGS. 1 to 3.

*QI! 11(7)-'lj"I(04188% l
tDol-, C(7) I In Fig. 1, No. 9
Portions corresponding to those in the figures are designated by the same reference numerals and redundant explanation will be omitted.

In FIG. 1, a peak hold circuit (41) is supplied with a continuous analog signal from a low pass filter (34). The output of the peak hold circuit (41) is supplied to a level detection comparator (42). comparator(
The output of 42) is supplied to a pulse generation circuit (44) via a one-scanning period delay circuit (43). In the case of FIG. 2, the delay amount of the delay circuit (43) may be two or three scanning periods. The output pulses of the pulse generation circuit (44) are supplied to a gate (45) interposed between the data reproduction circuit (37) and the data processing circuit (38).

The operation of this embodiment is as follows. In this example, since recent photodetecting elements and optical systems have been improved and their resolution has improved, the photodetecting element is configured so that several photodetecting elements correspond to one focal point. There is. The length of the scanning period by the scanning circuit (31) and the card feeding speed by the roller (2) are determined so that one track is scanned several times according to this resolution.

As a result, 1 11! in each scan period! i+ pin)
The relative position of P2 and the corresponding one photodetection element S moves as shown by So''Sv in FIG.

The output of the photodetecting element S is determined by the relative position with respect to the pit P2, as shown in FIG. The average value is obtained at 82 and S6. The same applies to other tracks.

Since the peak value of the readout signal obtained from the photodetector in each scanning period is nothing but the level shown in FIG. 3A,
The read signal is sent from the amplifier (32) to the low-pass filter (34)
The output signal of the peak hold circuit (41) supplied via the peak hold circuit (41) is the same as that shown in FIG. 3A. If the reference voltage of the comparator (42) is made to match the average value of this output signal (corresponding to 82 and S6 in FIG. 2), the output signal (■) of the comparator (42) will be
As shown in , the output signal (O) of the peak hold circuit (41) becomes "H" during the period when it is greater than the average value, and becomes "Lo" during the period when it is less than the average value.
42) is delayed by one scanning period by a one scanning period delay circuit (43), as shown in FIG. 3C, and is supplied as a trigger to a pulse generating circuit (44).

The pulse generation circuit (44) generates a gate pulse ■ whose pulse width is equal to one scanning period as shown in the third diagram (
45).

Therefore, the gate (45) is the peak hold circuit (41)
is opened for one scan period (corresponding to 83 in FIG. 2) following the scan (corresponding to 82 in FIG. 2) in which the output signal ■ has reached its average value, as is clear from FIG. Thus, accurate data stably reproduced by the data reproducing circuit (37) from the high contrast readout signal is transferred to the data processing circuit (38), and reliable data processing is performed.

Furthermore, as is clear from FIG. 3A, if the level of the output signal of the photodetector element is in the range of scans 33 to S5 exceeding its average value, a readout signal with the recommended contrast can be obtained as described above. The delay time of the delay circuit (43) may be two or three scanning periods.

Historically, in this embodiment, each trunk is scanned multiple times, so even if the timing of scanning is shifted, the information on two tracks will not be read out at the same time as in the prior art.

It should be noted that the present invention is not limited to the above-described embodiments, and those skilled in the art will easily understand that various modifications can be made.

〔Effect of the invention〕

As described in detail above, according to the present invention, a photodetecting element is scanned multiple times per track, and when it is detected that the output of the photodetecting element has exceeded a predetermined level, one scan that exceeds the predetermined level is performed. Since the data is read out during the period, the contrast of the bit-corresponding signals is improved, and two adjacent tracks are not read at the same time, making it possible to stably read correct recorded information.

[Brief explanation of the drawing]

FIG. 1 shows an optical card scanning device according to the present invention.
, , : Block diagram showing one embodiment, FIGS. 2 and 3
The figures are diagrams and time charts for explaining the present invention, FIGS. 4 and 5 are plan views of the optical card and enlarged views of essential parts thereof, and FIGS. 6, 7, and 9 are for explaining the present invention. 1 is a side view, a perspective view, and a block diagram showing a configuration example of a conventional optical card reading device, and FIGS. 8, 10, and 11 are diagrams for explaining the conventional device. (1) is an optical card, αω is a photodetection element, (31) is a scanning means, (42) is a comparator, (43) is a one-scanning period delay circuit, (44) is one-scanning period pulse generation circuit, (
45) is a gate, and T is a track. Figure 4 5th

Claims (1)

[Claims] An optical card is used in which information signals are recorded in a plurality of parallel tracks so as to be optically readable by an array of optical recording traces, and a plurality of detection elements are arranged in a straight line, and a plurality of detection elements are arranged in a linear manner, In the optical card reading device, the optical card reading device includes a photodetecting element for detecting the reading light of the track, and a scanning means for electrically scanning the photodetecting element to obtain an output signal. a level detection means for detecting that the level of the output signal of the photodetection element is equal to or higher than a predetermined value; a delay means for delaying at least one scanning period of the scanning means within the range of the plurality of scans in which the level of the output signal of the element exceeds the predetermined value; and a delay means for delaying the output of the photodetecting element based on the output of the delay means. 1. An optical card reading device comprising: extraction means for extracting a signal or a signal based on the signal for only one scanning period of the scanning means.