JP3456255B2 - Optical detector and bar code reader - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical detecting device and a bar code reading device. Specifically, the optical sensing device such as an optical sensor or bar code reader <br/> Ri apparatus using a resonant optical scanner, and more particularly to a bar code reader.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional bar code reading apparatus A using a polygon scanner 1. The polygon scanner 1 is configured such that the polygon mirror 2 having a regular polygon shape is rotated at a constant speed by a servomotor or the like, and the light beam r emitted from the light source 3 and collimated by the collimator lens 4 is used. When reflected by, the light beam r is scanned in one direction due to the rotation of the polygon mirror 2. When the light beam r is scanned on the bar code 5, the diffused light r reflected on the bar code 5 is received by the light receiving element 6 for reading the bar code, and the light receiving element 6 is received.
2 to the signal processing circuit 7, the bar code signal p as shown in FIG. 2B corresponding to the bar and the space of the bar code 5 is output. Further, a light receiving element 8 for a light beam monitor is provided at the scanning start end of the scanning area of the light beam r,
When the light beam r is emitted to the scanning start end, the light receiving element 8 detects the light beam r and generates an electric signal, and from the start signal s generation circuit 9 to the signal processing circuit 7, it is performed every optical scanning. The start signal s as shown in FIG. 2A is output. Therefore, the bar code signal p between the start signal s and the start signal s becomes the bar code signal p for one scan, and the signal processing circuit 7 starts the decoding process from the start signal s and decodes until the next start signal s. The bar code 5 is read after processing. This makes it easier for the signal processing circuit 7 to identify the bar code signal p, and simplifies the signal processing.

However, in the bar code reading apparatus A using the polygon scanner 1, if the polygon mirror 2 is made smaller, the scanning range of the light beam r becomes narrower, and it is difficult to make the polygon mirror 2 and the servomotor smaller. However, there is a drawback that the bar code reading device A becomes large.

Therefore, as a small bar code reader B, for example, a resonance type optical scanner 1 as shown in FIG.
A bar code reading device B using 1 is proposed. The resonance type optical scanner 11 shown in FIG. 5 is composed of a thin plate 12 and a driving source 13. The plate 12 has a movable portion having a vibration input portion 15 at one end of an elastic deformation portion 14 and a mirror portion 16 at the other end. 17 is formed, and the plate 12 is supported by joining the vibration input section 15 to the drive source 13 such as a piezoelectric element. A weight portion 18 is provided on one of the sleeves of the movable portion 17. Reference numeral 19 denotes a frequency-adjustable drive power supply for causing the drive source 13 to vibrate slightly at a desired frequency.

The elastic deformation section 14 has two elastic deformation modes, a torsional deformation mode and a bending deformation mode, and the driving source 13 receives an AC signal having a frequency equal to the resonance frequency f _T of the torsional deformation mode of the elastic deformation section 14. When the drive source 13 is vibrated by applying the voltage to the elastic deformation part 14, the elastic deformation part 14 resonates and vibrates in the torsional deformation mode, and the movable part 17 rotates around the P axis as shown in FIG. 6A. Therefore, the mirror unit 1 of the movable unit 17
When 6 is irradiated with the light beam r, the light beam r is one-dimensionally scanned in the θ _T direction. Further, the driving source 13 has a frequency equal to the resonance frequency f _B of the bending deformation mode of the elastic deformation portion 14.
Is vibrated, the elastic deformation portion 14 resonates and vibrates in the bending deformation mode along the P axis, and the movable portion 17 rotates about the Q axis as shown in FIG. 6B. Therefore, this movable part 17
When the light beam r is applied to the mirror section 16 of, the light beam r is one-dimensionally scanned in the θ _B direction. Also, the drive power source 1
9 to the vibration source 13 the resonance frequency f _T of the torsional deformation mode
When the signal of _{B and} the signal of the resonance frequency f _B of the bending deformation mode are superimposed and applied, the elastic deformation portion 14 simultaneously performs the resonance vibration of the bending deformation mode and the torsion deformation mode, and the movable portion 17 rotates around the P axis and Q. The light beam r
Are two-dimensionally scanned. Also, the scanning width around the P axis and Q
The scan width around the axis is adjusted by adjusting the voltage of the signal component output from the drive power source 19 having the frequency equal to the resonance frequency f _T of the torsion deformation mode and the voltage of the signal component having the frequency equal to the resonance frequency f _B of the bending deformation mode. Controlled by.

Since such a resonance type optical scanner 11 can be made extremely small, the barcode reader B can be made smaller than that using the polygon scanner 1 by using it. However, the resonance type optical scanner 11 is simply placed at the position of the polygon scanner 1.
However, the configuration is the same as that of the barcode reading apparatus A as shown in FIG. 1 using the polygon mirror 2 as shown in FIG. 3 except that the optical scanner 11 is different.

However, in the polygon scanner 1, the scanning direction of the light beam r is only one, whereas in the resonance type optical scanner 11, the movable portion 17 reciprocally oscillates, so that the light beam r is also reciprocally scanned. Become. Therefore, if the light receiving element 8 for monitoring is provided only at one end of the scanning area as in the conventional case, the start signal s is output only once in the reciprocating scanning (two scanning) in the start signal generating circuit 9. As shown in 4, the start signal s and the start signal s
There will be two bar code signals p between and. Therefore, it is necessary to separate or identify the two bar code signals p between the start signals s and perform the decoding process.
There is a problem that the signal processing in the signal processing circuit 7 becomes complicated and the processing becomes difficult.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide an optical system in which a scanning light beam r is reciprocally scanned by a resonance type scanner. It is to be able to obtain a processing start signal once per scanning in a detection device, particularly a bar code reading device.

[0009]

The optical detection device of the present invention is an optical detection device which reciprocally scans a light beam using a resonant optical scanner, wherein the light beam is scanned at either end of the scanning area. and a signal generating means for generating a scanning end detection signal when the said signal generating means, the both ends of the optical scanning area
It is characterized in that it has a light receiving element provided .

Another optical sensing device of the present invention is a resonant optical device.
An optical detector that scans a light beam back and forth using a scanner
Position, the light beam is scanned at either end of the scan area.
Equipped with signal generating means to generate scanning edge detection signal
The signal generating means is provided at one end of the light beam scanning area.
Light receiving element and when the light receiving element receives the light beam
Means for generating a first signal and a first signal from the first signal
1/2 cycle of signal of 1 or scanning cycle of light beam
To generate the second signal with a delay of 1/2 cycle
It is characterized by having steps.

Yet another optical sensing device of the present invention is
Optical system that scans a light beam back and forth using a vibrating optical scanner
At the detector, a light beam is placed at either end of the scan area.
Signal generating means for generating a scanning end detection signal when scanned
And the signal generating means is provided in the resonant optical scanner.
A comparison means for comparing the drive voltage with the reference voltage and the comparison means.
Signal from rising and falling of output voltage from the stage
And a means for generating.

[0012]

[0013]

[0014]

Further, the optical detection device is implemented as a bar code reading device for irradiating a bar code with a light beam, receiving the light reflected by the bar code, and processing the light reception signal to read the bar code. can do.

[0016]

According to the present invention, an optical system using a resonant scanner is used.
-Type detector equipped with light-receiving elements at both ends of the light beam scanning area
By doing so, the light beam is scanned to both ends of the scanning area.
The scanning end detection signals output from both light receiving elements are processed and opened
Since signal processing for one scan can be performed as the start signal, signal processing
It makes sense.

[0017]

[0018]

Further, a light receiving element is provided at one end of the light beam scanning area to generate a first signal when the light receiving element receives light,
The second signal is delayed from the first signal by 1/2 cycle of the cycle of the first signal or 1/2 cycle of the light beam scanning cycle.
If the signal is generated, the second signal can be made to substantially coincide with the timing at which the other end of the light beam scanning area is scanned by the light beam. Therefore, the scanning signal is generated by the first signal and the second signal. Scan end detection signals corresponding to both ends can be created.

Alternatively, if the drive voltage of the resonance type optical scanner is compared with a reference voltage and a signal is generated by rising and falling of the output voltage from the comparing means, the rising signal and the rising edge are generated due to the characteristics of the resonance type scanner. Since the falling signal corresponds to the maximum rotation angle of the optical scanner, it can be used as the scanning end detection signal corresponding to both ends of the scanning area of the light beam.

[0021]

FIG. 7 is a schematic block diagram showing a bar code reading apparatus C according to an embodiment of the present invention. In this bar code reading apparatus C, the light projecting system includes a light source 3 such as a light emitting diode or a semiconductor laser element, and a collimating lens 4.
And a resonance type optical scanner 11. The resonant optical scanner 11 has a structure similar to that described with reference to FIGS. 5 and 6A and 6B. However, as the drive source 13, an electromagnet or the like may be used instead of the piezoelectric element, but the barcode reader C can be downsized by using a small solid element such as a piezoelectric element. The bar code reading light receiving system includes a light receiving element 6 such as a photodiode or a phototransistor and a signal processing circuit 7. Then, after the light beam r emitted from the light source 3 is collimated by the collimator lens 4, the light beam r is made incident on the optical scanner 11 and is reflected by the mirror section 16, and the reflected light beam r is left and right. It is reciprocally scanned in both directions. If the bar code 5 exists in the scanning direction of the light beam r, the bar code 5
The diffused light r reflected by is received by the light-receiving element 6 for reading the bar code, and the light-receiving element 6 transfers from the light-receiving element 6 to the signal processing circuit 7 according to the bar and space of the bar code 5 in FIG.
A bar code signal p such as is output.

The light receiving system for the scanning end monitor is composed of two light receiving elements 20a and 20b respectively arranged at both ends of the light beam scanning area, and a start signal generating circuit 21. When any of the light receiving elements 20a and 20b is scanned by any one of the ends of the scanning area, the start signal generation circuit 21 outputs a start signal s (scan end detection signal) to the signal processing circuit 7. FIG. 8 is a block diagram showing a configuration example of the start signal generation circuit 21, and when the light beam r is scanned to one end of the scanning area and the light receiving element 20a at that position receives the light beam, as shown in FIG. 9A. A pulse generator 22a that generates a pulse signal a and a light beam r is scanned to the other end of the scanning area and the light receiving element 20b at that position receives a pulse signal b as shown in FIG. 9B. Pulse generator 22b and double pulse generator 2
2a and 22b are combined to generate a start signal s as shown in FIG. 9 (c) by combining the pulse signals a and b and output to the signal processing circuit 7.

Therefore, in the signal processing circuit 7, the light beam r
Receives a start signal s as shown in FIG. 9C in synchronism with the timing at which scanning is performed to the left and right ends of the scanning area and the scanning is started, and one scan is provided between the start signal s and the start signal s. The bar code signal p is received. And
At the same time as receiving the start signal s, the decoding process of the bar code signal p is started, and the decoding process is ended by the next start signal s. At the same time, the decoding process of the next bar code signal p is started by the start signal s. In this way, in the signal processing circuit 7, the bar code signal p for each one scan divided by the start signal s can be decoded, so that the signal processing in the signal processing circuit 7 can be simplified. .

Since the light receiving elements 20a and 20b for monitoring are provided on both sides of the scanning area, the light receiving element 2 is provided at the end of the scanning area.
If it is made to fluctuate within the light receiving surface of 0a, 20b,
The change in the scanning width of the light beam r can be easily monitored from the change in the pulse width of the start signal s (or the pulse signals a and b). Therefore, by monitoring the pulse width of the start signal s, it is possible to check the amplitude fluctuation at the time of abnormality due to deterioration of the optical scanner 11 and to notify the replacement time of the optical scanner 11. Although photodiodes can be used as the light receiving elements 20a and 20b, if a position detecting element (PSD) is used, it is possible to more accurately monitor the fluctuation of the scanning area and the amplitude change of the optical scanner 11.

FIG. 10 is a schematic block diagram showing a bar code reading device D according to another embodiment of the present invention. In this embodiment, the light receiving system for the scanning end monitor is composed of two mirrors 24a and 24b, one light receiving element 20, and a start signal generating circuit 21. Each mirror 2
4a and 24b are light beams r by the resonance type optical scanner 11.
Are arranged at both ends of the scanning area of each of the mirrors 24a, 2a.
4b has its direction adjusted so that the scanning light beam r reflected at the end of the scanning area enters the light receiving element 20. In this embodiment, since the light beams r scanned to the left and right ends of the scanning area are optically combined, the start signal generating circuit 21 can be simplified. That is, the start signal generating circuit 21 is composed only of the pulse generating section 25, and the pulse generating section 25 has the light beam r reflected by the light receiving element 20 by the mirrors 24a and 24b as shown in FIGS. Every time the light is received, that is, every scan, a start signal s is output, and each bar code signal p for one scan is divided by the start signal s.

In this embodiment, the configuration of the signal processing circuit 7 can be simplified as described above, and the light receiving element is
Since the number can be reduced, the cost can be reduced. Further, if the mirrors 24a and 24b are appropriately arranged, the scanning width variation and the optical scanner 1 can be changed similarly to the above-described embodiment.
It is also possible to monitor the vibration amplitude of 1.

FIG. 13 is a schematic block diagram showing a bar code reading apparatus E according to still another embodiment of the present invention. In this embodiment, the light receiving system for the scanning end monitor is 1
It is composed of one mirror 24, one light receiving element 20, and a start signal generating circuit 21. The mirror 24 is arranged at one end of the light beam scanning area, and the light receiving element 20 is arranged at the other end of the light beam r scanning area.
4 is adjusted in direction so that the light beam r reflected at the scanning end is incident on the light receiving element 20, and the light receiving element 20 is reflected by the mirror 24 and the light beam r scanned from the optical scanner 11 to the scanning end. The light beam r is directed so that it can be received. In this embodiment, since the number of mirrors can be reduced, the configuration can be simplified and the cost can be reduced.

FIG. 14 is a schematic block diagram showing a bar code reader F according to still another embodiment of the present invention, and FIG. 15 is a block diagram showing a start signal generating circuit 21 thereof. In this bar code reader F, the light receiving element 2 for monitoring is provided only at one end of the scanning area of the light beam r.
0 is set. As shown in FIG. 15, the start signal generation circuit 21 includes a pulse generation unit 26 that generates a first pulse signal a when the light receiving element 20 receives light, and a pulse generation unit 26.
Generates a first pulse signal a, the scanning period (reciprocating scanning time) 2T of the light beam r from the first pulse signal is 1 /
The delay unit 27 delays the time T of 2 and outputs the signal c.
And a pulse generator 28 that generates a second pulse signal b when the delay signal c is output from the delay unit 27, and a first pulse signal a and a second pulse signal b from the pulse generators 26 and 28. And a pulse synthesizing unit 29 for synthesizing and outputting as a start signal s.

FIG. 16 is a diagram showing a specific circuit of the start signal generating circuit 21 performing the above operation, and FIG. 17 is a waveform diagram of each part in the start signal generating circuit 21. The pulse generator 26 includes a transistor 30, an operational amplifier 31, and a diode 32. The light receiving element 20 is connected between the base and collector of the transistor 30, and the collector voltage of the transistor 30 is connected to the inverting input terminal of the operational amplifier 31. Output is diode 3
The signal is output as an output signal of the pulse generation unit 26 through 2. Then, when the light receiving element 20 receives light and generates a photoelectromotive force, the output of the pulse generation unit 26 decreases, so that when a light beam is incident on the light receiving element 20 arranged at the end of the light beam scanning area, a pulse is generated. The section 26 outputs a first pulse signal a as shown in FIG. The output of the pulse generator 26 is input to the multivibrator 33 that constitutes the delay unit 27 and the AND element 34 that constitutes the pulse synthesizer 29. As shown in FIG. 17B, the multivibrator 33 that constitutes the delay unit 27 is inverted to the L level by the input signal (that is, the pulse signal a output from the pulse generation unit 26) and is preset. When the delay time T elapses, the operation returns to the H level. In addition, the pulse generator 28 also includes the multivibrator 3
The multi-vibrator 35 is configured by the second pulse signal b by the rising operation (delay signal c) of the input signal (that is, the output of the delay unit 27), as shown in FIG. 17C. Is output. The output of the pulse generator 28 is also the AND element 3 of the pulse synthesizer 29.
It is entered in 4. Therefore, as shown in FIG. 17D, the pulse synthesizing unit 29 synthesizes the first pulse signal a and the second pulse signal b and outputs them as the start signal s. Here, since the scanning period 2T of the optical scanner 11 is known in advance, the delay time of the multivibrator 33 is set to be equal to the one-side scanning time T thereof.

This bar code reading device F
In the above, the light beam r incident on the light receiving element 20 at the right end of the light beam scanning region generates the start signal a at the right end in the pulse generator 26. The start signal a at the right end is input to the delay unit 27, and the delay unit 27 and the pulse generation unit 28 generate a start signal b on the left side delayed from the start signal a at the right end by the one-side scanning time T. In this way, the right start signal a and the left start signal b are combined by the pulse combiner 29 and output to the signal processing circuit 7 as left and right start signals s. Thereby, FIG. 17 (d) (e)
As shown in FIG. 5, the start signal s and the barcode signal p for one scan are alternately input to the signal processing circuit 7, which facilitates signal processing.

In this embodiment, the mechanical structure and arrangement of the light receiving element 20 and the like are the same as in the conventional example, and only the start signal generating circuit 21 can be replaced. Also in this embodiment, the fluctuation of the scanning width and the vibration amplitude of the optical scanner 11 can be monitored.

FIG. 18 is a schematic diagram showing another bar code reading device G of the present invention. In this embodiment, the start signal s is generated without using a light receiving element for monitoring or a mirror. In the start signal generation circuit 21 of this embodiment, the drive voltage (drive waveform) applied to the drive source 13 of the resonant optical scanner 11 is monitored, and the start signal s corresponding to both ends of the scanning area is thereby monitored. Is generating. Figure 1
9 is a block diagram showing the configuration of the start signal generating circuit 21, and FIG. 20 is a specific circuit diagram thereof. The input stage of the start signal generation circuit 21 is composed of a comparator 36. Specifically, as shown in FIG. 20, the average voltage of the drive voltage V of the optical scanner 11 (drive voltage It is composed of an operational amplifier 40 and a diode 41 to which a reference voltage of a value equal to the DC component) V _DD is applied and the drive voltage V of the optical scanner 11 as shown in FIG. Therefore, in the comparator 36, the reference voltage V _DD is compared with the drive voltage V, and from the comparator 36, as shown in FIG. 21 (b), a cycle of ½ of the cycle of the drive voltage V (= one direction of the light beam). The comparison signal d that is inverted every scanning time T) is output. The comparison signal d output from the comparator 36 is a pulse generator 37 including a multivibrator 42 that outputs a pulse signal a in response to a falling operation of the input signal.
And a pulse generator 38 including a multivibrator 43 that outputs a pulse signal b in response to a rising operation of the input signal. Therefore, both pulse generators 3
The pulse signals a and b are alternately output from the drive signals 7 and 38 at the cross points of the drive voltage V of the optical scanner 11 and the average voltage V _DD, and both pulse signals a and b are output to the pulse synthesizing unit 39.
By synthesizing with the (AND element 44), the pulse synthesizing unit 39 outputs the start signal s every time a half scanning period (T / 2) shifts from the upper and lower peak values of the drive voltage V of the optical scanner 11. Since it is known that the vibration direction of the optical scanner 11 and the phase of the drive voltage V are deviated by 90 degrees, the start signal s thus obtained corresponds to both ends of the scanning region of the light beam r. Figure 2
As shown in 1 (e) and (f), the start signal s and the barcode signal p for one scan are alternately input to the signal processing circuit 7, which facilitates signal processing. Further, since the light receiving element and the mirror are not used, the cost can be reduced and the barcode reading device G can be downsized.

In each of the above-mentioned embodiments, the case where it is implemented as a bar code reading device has been described, but the present invention can also be implemented in an optical detecting device other than the bar code reading device. For example, it can also be used as an optical sensor using a resonant optical scanner for detecting the presence or absence of an object in a certain area, its position, shape, and the like.

[0034]

In the optical detecting device and the bar code reading device of the present invention, there is provided the signal generating means for generating the scanning end detection signal when the light beam is scanned at either end of the scanning area. Therefore, in the signal processing circuit, the bar code signal input from the light receiving element for reading the bar code can be discriminated for each scanning by using the scanning end detection signal as a mark. Therefore, the signal processing circuit can perform the signal processing for each scanning by using the scanning end detection signal as the processing start signal, and the signal processing in the signal processing circuit portion can be easily and easily performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a conventional bar code reading device.

2A and 2B are waveform diagrams showing a start signal and a bar code signal of the above.

FIG. 3 is a schematic configuration diagram showing another conventional barcode reading device.

4A and 4B are waveform diagrams showing a start signal and a bar code signal of the above.

FIG. 5 is a perspective view showing the structure of a resonant optical scanner.

6 (a) and 6 (b) are operation explanatory views of the above.

FIG. 7 is a schematic configuration diagram showing a barcode reading apparatus according to an embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a start signal generating circuit of the above.

9 (a), (b), (c) and (d) are diagrams showing signal waveforms of respective parts of the same.

FIG. 10 is a schematic configuration diagram showing a barcode reading device according to another embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of a start signal generating circuit of the above.

12 (a) and 12 (b) are diagrams showing signal waveforms of respective parts of the same.

FIG. 13 is a schematic configuration diagram showing a barcode reading device according to another embodiment of the present invention.

FIG. 14 is a schematic configuration diagram showing a barcode reading device according to another embodiment of the present invention.

FIG. 15 is a block diagram showing a configuration of a start signal generating circuit of the above.

FIG. 16 is a specific circuit diagram of the start signal generating circuit of the above.

17 (a), (b), (c), (d) and (e) are diagrams showing signal waveforms of respective portions of the same.

FIG. 18 is a schematic configuration diagram showing a barcode reading device according to another embodiment of the present invention.

FIG. 19 is a block diagram showing a configuration of a start signal generating circuit of the above.

FIG. 20 is a specific circuit diagram of the start signal generating circuit of the above.

21 (a), (b), (c), (d), (e), and (f) are diagrams showing signal waveforms of respective parts of the same.

[Explanation of symbols]

3 light sources 5 barcode 7 Signal processing circuit 11 Resonant optical scanner 20, 20a, 20b Light receiving element 21 Start signal generation circuit 24, 24a, 24b mirror r light beam s Start signal p bar code signal

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hidenobu Umeda, 10th Hanazono Todocho, Ukyo-ku, Kyoto Prefecture, Kyoto Omron Co., Ltd. (72) Inventor Masahiro Yoneda 10th Hanazonotodo-cho, Ukyo-ku, Kyoto City, Kyoto Omron Corporation (72) Inventor Atsushi Irie 10 Hanazono Todo-cho, Ukyo-ku, Kyoto Prefecture Omron Co., Ltd. (72) Inventor Kiyotoshi Okura 10 Hanazono-Tudo-cho, Ukyo-ku, Kyoto City, Kyoto (72) Inventor Masateru Ikeda 10 Ouron Co., Ltd., Hanazono Todo-cho, Ukyo-ku, Kyoto, Japan (72) Inventor Hiromi Toya 10 Oenron Co., Ltd., Hanazono-Tudo-cho, Ukyo-ku, Kyoto, Kyoto (56) Reference JP-A 63-133281 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B 26/10 G06K ⁷ /10-7/14

Claims (4)

(57) [Claims] 1. An optical detection device for reciprocally scanning a light beam using a resonance type optical scanner, comprising signal generating means for generating a scanning end detection signal when the light beam is scanned at either end of a scanning region. And the signal generating means includes optical scanning
An optical detection device having light-receiving elements provided at both ends of the region . 2. A light beam is forwarded using a resonant optical scanner.
In the optical detector that scans backward, the light beam is scanned
Generates scan edge detection signal when scanned at either edge of
And a signal generating means for said signal generating means includes a light receiving element provided to one end of the optical beam scanning range, the light receiving element is light
Means for generating a first signal when a beam is received; and a second signal delayed from the first signal by 1/2 cycle of the cycle of the first signal or 1/2 cycle of the scanning cycle of the light beam. optical sensing apparatus characterized in that it has a means for generating a signal. 3. A light beam is forwarded using a resonant optical scanner.
In the optical detector that scans backward, the light beam is scanned
Generates scan edge detection signal when scanned at either edge of
And a signal generating means for said signal generating means, comparing means and the signal at the rising and falling of the output voltage from the comparison means for comparing the driving voltage of the co <br/> vibration type optical scanner and a reference voltage optical sensing apparatus characterized in that it has a means for generating a. Wherein a light beam is irradiated on the bar code, and receiving the light reflected by the bar code, the bar code reader reading a bar code by processing signals received light signals, according to claim 1, 2 or 3 A bar code reading device using the optical detection device described in 1.