JPS6226059B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a barcode reading device that uses a semiconductor laser as a light source.

Conventional Structures and Problems There are known barcode reading devices including stationary scanners with a fixed reading section and hand scanners in which the reading section is operated by a person.

Conventional stationary scanners use He-Ne lasers as light sources. He−Ne laser is 6328Å
It oscillates at wavelengths in the visible region ^of This was both difficult and inconvenient in practical terms.

Recently, a semiconductor laser has been realized in place of a He-Ne laser as the light source. Semiconductor lasers are small, do not require a high-voltage power supply, and have a long lifespan, but their oscillation wavelength is in the near-infrared region of 7,600 Å to 8,500 Å, so visibility is poor, and even when scanning with a semiconductor laser as a light source, the scanning light The trajectory of the barcode could not be seen, and the range in which the barcode could be read was unclear. Also, He−Ne
With a laser, it was possible to limit the orientation of the barcode and read it in order to miniaturize the device because the trajectory of the scanning light could be seen, but with a semiconductor laser, the trajectory cannot be seen, so the laser output is limited. There was a problem with integrity because there was a possibility that the user would continue to stare at the object even though the user was using the computer.

OBJECTS OF THE INVENTION The present invention aims to eliminate the above-mentioned conventional problems and to enable the safe use of a semiconductor laser as a light source for a barcode reading device.

Structure of the Invention In order to achieve the above object, the present invention uses a semiconductor laser as a light source and at the same time uses a visible light source so that the position and size of the scanning light pattern of the semiconductor laser can be confirmed. This has the effect of recognizing the scanning light pattern and enabling barcode reading operations.

DESCRIPTION OF EMBODIMENTS The structure of an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of the optical system of this device, in which 1 is a semiconductor laser light source, 2 is a projection lens, 3 is a reflection mirror, 4 is a rotating mirror,
5 is a reflective mirror for forming a barcode pattern, 6 is a barcode reading surface, 7 is a visually perceivable light source, 8 is a barcode pattern guide plate (slit plate), and 9 is a visible light projected onto the reading surface 6. No barcode pattern, 10 is barcode reading window, 1
1 is a mirror with a hole, 12 is a condenser lens, 13 is an optical filter that passes only the spectrum of the semiconductor laser, and 14 is a photoelectric conversion element.

FIG. 2 shows a spectral curve A of a visually perceptible light source, for example tungsten light, and a spectral curve B of a semiconductor laser light.

Next, the operation of the above embodiment will be explained. 1st
In the figure, light emitted from a semiconductor laser light source 1 is focused by a projection lens 2 onto a reading surface 6 to a spot size (spot diameter) that is less than the resolution of a barcode pattern. The focused light passes through the hole of the perforated mirror 11, hits the reflection mirror 3, and is turned into scanning light by the rotating mirror 4. In this case, similar results can be obtained by using a vibrating mirror instead of the rotating mirror 4. The scanning light hits the pattern-forming reflection mirror 5 and passes through the reading window 10 to form a barcode scanning pattern 9 on the reading surface 6.

However, in this state it cannot be visually detected. With a visually perceivable light source 7,
By illuminating the pattern guide 8 and projecting its silhouette onto the reading surface 6, the pattern guide plate 8 presents a guide image similar to the scanning pattern 9 on the reading surface 6. Similarly, the shadow of the pattern guide of the barcode forming reflective mirror 5 irradiated by the light source 7 becomes the same as the barcode scanning pattern 9 and can be visually detected, and the shadow on the reading surface 6 by the light source 7 is the same as the barcode scanning pattern 9. Since the light emitting direction is the same as the scanning light by the semiconductor laser, the same effect can be obtained even if the light passes over the reading surface 6 when reading the barcode.

FIG. 3 shows the structure of an embodiment of the pattern guide plate 8, in which 301 is a material that does not allow the light from the light source 7 to pass through, 302 is a material that allows the light to pass through, or a slit portion, so that it is visible on the reading surface 6. Capturing possible scanning patterns. Conversely, 301 is the light source 7
If the material 302 is made of a material that allows light to pass therethrough, and the material 302 is made of a material that does not allow light to pass through, the surroundings will be visible on the reading surface 6 and the scanning pattern will be dark. An image similar to the scanning pattern 9 can be obtained no matter which pattern guide plate is used. A signal obtained by scanning the barcode can be obtained along the optical path.
That is, the light passes through the reflecting mirror 5, the rotating mirror 4, the reflecting mirror 3, is reflected by the perforated mirror 11, is focused by the condensing lens 12, and after passing through the optical filter 13, is converted into electricity by the photoelectric conversion element 14. converted into a signal. There is no problem if the wavelength spectrum of the semiconductor laser and the wavelength spectrum of the light source 7 are completely separated, but if the wavelength spectra overlap, the pattern guide plate 8 must be provided with an optical system that does not allow the wavelength spectrum of the semiconductor laser to pass through. This can be easily achieved by inserting a filter.

Effects of the Invention The present invention has the above-described configuration, and provides the following effects.

(1) By configuring a light source in the visible light range that can be visually detected, the position and size of the scanning light pattern of a semiconductor laser, which was previously impossible, can be realized by creating a barcode with the scanning pattern in mind. Read operation becomes possible.

(2) By providing a pattern guide in the same direction as the scanning light from the reading surface, a substantially similar scanning pattern can be obtained above the reading surface.

(3) By separating the wavelength spectra of the scanning light and the light source for irradiating the guide plate, or by providing an optical filter on the guide plate, there is no adverse effect on the S/N ratio of the reception of the scanning light.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an optical system in an embodiment of the present invention, FIG. 2 is a wavelength spectrum diagram of a light source, and FIG. 3 is an enlarged plan view of a pattern guide plate in an embodiment of the present invention. 1... Semiconductor laser light source, 4... Rotating mirror,
5...Reflection mirror for barcode pattern formation, 6
...Barcode reading surface, 7...Visually perceivable light source, 8...Barcode pattern guide plate, 1
4...Photoelectric conversion element.

Claims (1)

[Scope of Claims] 1. A semiconductor laser, an optical system that projects the light of this semiconductor laser onto a reading surface, an optical scanning converter that converts the semiconductor laser light that has passed through this optical system into scanning light, and an optical scanning system including a reflective mirror that projects a scanning pattern onto a reading surface; a visible light source; and a guide plate that projects an image illuminated by the light source that matches the position and shape of the scanning pattern onto the reading surface. A barcode reading device comprising: the guide plate and the visible light source provided substantially on an extension line in the direction of a reading surface on which the scanning pattern is projected. 2. The barcode reading device according to claim 1, wherein the guide plate is made of a member that removes the wavelength spectrum of the semiconductor laser.