JPH06162242A - Bar-code reader - Google Patents

Abstract

PURPOSE:To provide the bar-code reader which can eliminate adverse influence of a disturbance light caused by a three-wavelength type high frequency fluorescent lamp, etc., exerted on read of a bar-code label executed by the bar-code reader by only adding simple constitution parts. CONSTITUTION:In the bar-code reader 1 having a laser scanner for scanning a bar-code label 4 at high speed, and a decoder for photodetecting a reflected light 3 from the bar-code label 4, amplifying a converted video signal and decoding the signal, the laser scanner is provided with auxiliary light sources 6-1-6-2 having an irradiation light of high light energy of the same wavelength band as a scanning laser light, in addition to a laser tube for emitting the scanning laser light 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code reader, and more particularly to JAN, U printed on merchandise in the retail industry.
A POS system that automatically reads barcode labels on PCs, or ITF (Interle) used for logistics.
The present invention relates to a barcode reader for automatically reading barcode labels such as aved 2 out of 5).

[0002]

2. Description of the Related Art As a conventional bar code reader,
For example, the device shown in FIG. 7.113 on page 239 of Hajime Hattori, "Utilization of Optoelectronics" (Taiga Publishing, December 1984) is known. In this device, only the laser beam irradiates the bar code label, and there is no idea that other auxiliary light sources are used. Also,
In the "checkout device" disclosed in Japanese Patent Laid-Open No. 4-105184, the height of the bar code scanner is made variable so as to reduce the reading failure rate. However, the auxiliary light source is also used here. I can not see the idea.

[0003]

Generally, a He-Ne laser having an output of 5 mW or less is used as a laser beam for scanning a bar code label from the viewpoint of safety. For this reason,
The illuminance in the vicinity of the bar code reader of the indoor lighting device that becomes the ambient light is about 3000 Lx or less, and the signal level of the scattered light obtained by scanning the barcode with the laser light is smaller than the direct noise level of the ambient light. I try not to become. However, the illuminance is shown in FIG.
A conventional continuous-wavelength fluorescent lamp (general white or general daylight color) and a three-wavelength fluorescent lamp characterized by brightness and color, an example of which is shown in FIGS. 2 (a) to 2 (c). This is an average value even if and have the same value,
In the 630 nm band, which is the wavelength of the He-Ne laser light that is generally used in the conventional bar code reader (see FIG. 3), the energy of the lamp in FIG. 2 (c) increases by one digit or more. Therefore, when a light bulb color three-wavelength fluorescent lamp as shown in Fig. 2 (c) is used for indoor lighting, the noise of wavelength 630nm incident on the light receiving part of the bar code reader is emitted from the continuous wavelength lamp. It increases by one digit or more as compared with noise, reduces the S / N ratio with the reflected signal from the barcode label, and induces a malfunction.

On the other hand, recently, in order to prevent the flicker of the fluorescent lamp, a high frequency lighting type fluorescent lamp is often used. FIGS. 4 (a) and 4 (b) show the influence of fluorescent lamp irradiation on the bar code reader in an illumination environment using the incandescent color three-wavelength high-frequency fluorescent lamp as shown in FIG. 2 (c). First, FIG. 4A shows three wavelengths which are incident in an angle range (shaded range in the figure) corresponding to the emission direction of the laser beam from the bar code reader and the incident direction of the reflected light from the bar code label. The irradiation light of the high-frequency fluorescent lamp
It shows that it adversely affects the reading of the barcode label by the barcode reading device. The angle range that is adversely affected in this case has a certain width depending on the specifications of the bar code reader, but is generally within a range of 30 to 70 degrees from the horizontal plane. In addition, FIG. 4 (b) shows the 3 shown in the above example.
Lighting frequency of wavelength type high frequency fluorescent lamp (30-50KH
It is shown that the noise component of 10 times component (300 to 500 KHz) of z) is superimposed on 300 KHz to 1 MHz which is the barcode signal sampling frequency of the laser light (wavelength 630 nm band).

That is, since the well component of the irradiation light of the three-wavelength type high frequency fluorescent lamp which is incident in the angle range as shown in FIG. This adversely affects the reading of the barcode label. As a measure for improving the S / N, a method of increasing the light energy of the laser light can be considered,
This is because it cannot be adopted from the viewpoint of protecting the visual function of the operator and others. The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the above-described problems in the conventional technique and to add a barcode label by a barcode reading device only by adding simple components. An object of the present invention is to provide a bar code reader capable of eliminating the adverse effect of ambient light such as a three-wavelength high-frequency fluorescent lamp on reading.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser scanner which scans a barcode label at high speed, and a decoder which receives reflected light from the barcode label and amplifies the converted video signal and decodes the signal. In the bar code reader having the above, the laser scanner is provided with an auxiliary light source having irradiation light with high light energy in the same wavelength band as the scanning laser light, in addition to the laser tube for emitting the scanning laser light. It is achieved by a bar code reader characterized in that

[0007]

In the bar code reading apparatus according to the present invention, the bar code label to be read is irradiated by the auxiliary light source additionally provided which has irradiation light with high optical energy in the same wavelength band as the scanning laser light. By doing
The level of the signal reflected from the bar code label can be relatively improved compared to the disturbance noise due to indoor lighting, and the S / N ratio can be improved.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a state in which a bar code reader according to an embodiment of the present invention is used under indoor lighting. In the figure, 1 is a bar code reader, 2
Is a laser beam emitted from a laser light source provided in the bar code reading apparatus 1, and 3 is a reflected light when the laser beam 2 irradiates a bar code level 4 attached to an article to be read ( Reflected signal). Auxiliary light sources 6-1 and 6-2 are provided on the upper surface of the bar code reader 1 according to the present embodiment, and the auxiliary light sources 6-1 and 6-2 are provided.
From the above, the auxiliary lights 6-1-1 and 6-2-1 are configured to irradiate the above-mentioned bar code label 4.

In the bar code reading apparatus 1 according to this embodiment constructed as described above, the auxiliary lights 6-1-1 and 6-2-1 emitted from the auxiliary light sources 6-1 and 6-2 are bar-coded. By irradiating the code label 4, the signal level of the reflected light (reflected signal) 3 from the bar code level 4 is increased, and S / for the ambient light 5-1 incident on the bar code reading device 1 from the indoor lighting 5 This produces the effect of improving the N ratio. The auxiliary light sources 6-1 and 6-2 are the bar code labels 4
Is installed so as to emit light in the same direction as the scanning laser light emitted from the laser light source provided in the barcode reading device 1 in the direction in which the laser light source provided in the barcode reading device 1 is effective. There is. As a result, the irradiation light 5-2 from the indoor lighting 5 cannot be irradiated, and the irradiation light amount of the bar code irradiated with the reflected light 5-4 of the irradiation light 5-3 from the indoor lighting 5 is insufficient. Auxiliary light 6-1 emitted from 1, 6-2
-1, 6-2-1 makes up for it.

In the above embodiment, since the bar code label 4 is illuminated by the auxiliary light source in addition to the scanning laser beam, the level of the reflected signal from the bar code label 4 can be increased, and The S / N ratio can be improved as compared with the noise of the ambient light due to the illumination. As the auxiliary light sources 6-1 and 6-2 described above, by using the bulb color three-wavelength high frequency fluorescent lamp having the spectrum shown in FIG. 2C, the laser light shown in FIG. However, the present invention is not limited to this. Further, as shown in FIG. 5, the auxiliary light sources 6-1 and 6-2 may be installed on the scanner base 7 instead of being installed on the barcode reading device 1. Further, an optical filter 8 as shown in FIG. 5 is provided between the shopper's eyes 9-1, the operator's eyes 9-2 and the above-mentioned auxiliary light sources 6-1 and 6-2 to provide the auxiliary light source 6-. Auxiliary lights 6-1-1 and 6-2-1 emitted from 1 and 6-2 are attenuated to give glare to shoppers and operators as light beams 6-1-2 and 6-2-2. It is also possible not to.

[0011]

As described above in detail, according to the present invention, the disturbance caused by the three-wavelength high-frequency fluorescent lamp or the like exerts on the reading of the bar code label by the bar code reading device only by adding simple components. This is a remarkable effect that a bar code reader capable of eliminating the adverse effect of light can be realized.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a barcode reader according to an embodiment of the present invention is used under indoor lighting.

FIG. 2 is a wavelength-light energy emission distribution map of a commonly used fluorescent lamp.

FIG. 3 is a wavelength-optical energy emission distribution map of laser light.

FIG. 4 is a diagram for explaining the influence of a high frequency fluorescent lamp.

FIG. 5 is a perspective view showing a state in which a barcode reading device according to another embodiment of the present invention is used under indoor lighting.

[Explanation of symbols]

1: Bar code reader, 2: Laser beam, 3: Reflected light (reflected signal), 4: Bar code level, 5: Indoor lighting device, 5-1: Ambient light, 6-1 and 6-2: Auxiliary light source , 6-1-1, 6
-2-1: Auxiliary light.

Claims (1)

[Claims] 1. A laser scanner that scans a barcode label at high speed, and receives reflected light from the barcode label,
In a bar code reader having a decoder for amplifying the converted video signal and decoding the signal, in the laser scanner, in addition to a laser tube for emitting a laser beam for scanning, a light in the same wavelength band as the laser beam for scanning is added. A bar code reading device comprising an auxiliary light source having irradiation light with high energy.