JPS6358588A - Bar code reader - Google Patents

Abstract

PURPOSE:To visually recognize a scan range while a laser beam is scanning by forming a means passing through only a part with a high light intensity distribution in visible light between a light emitting diode and a display image forming means. CONSTITUTION:A cylindrical lens 13 receives the visible light 9 whose magnitude is controlled by a pin hole plate 10 from the light emitting diode 8. As a result a flat, long visible light projection area 23 corresponding to the scan range is formed on a scan surface 6 in the scanning direction of the laser beam 2. Since the laser beam 2 is a near infrared laser from a semiconductor laser 1, it cannot be visually recognized while it is scanning. However, with the pin hole plate 10 provided just before the light emitting diode 8, only the part with a high light intensity distribution in the center is passed through, and an image can be reduced without cutting down the size of a light source for the diode 8. Consequently the size of an image in a the area 23 in a direction X is made smaller, and the scan area can be recognized easily and visually through the area 23.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention scans a laser beam from a semiconductor laser on a scanning surface on which a bar code is applied, and uses reflected light from the scanning surface. The present invention relates to a barcode reading device that reads barcodes based on the following information.

(Prior Art) As is well known, barcode reading devices using laser light include a fixed scanner type as described in Japanese Utility Model Application No. 58-105648, and a fixed scanner type as described in Japanese Utility Model Application Publication No. 59-155653. As shown, hold the laser beam transmitter/receiver in your hand and scan the barcoded scanning surface with a wand ski.
There is also a one-sided type.

On the other hand, laser light sources include H8-No laser and semiconductor laser. He-Ne laser is 632.8
Since it oscillates at a wavelength in the visible range of nm, it is possible to confirm with the naked eye the scanning area that is actually being optically scanned on the barcoded scanning surface. However, this He-
Ne laser requires a high-voltage power source, has a large volume, and has a short lifespan of about 10,000 hours.

On the other hand, a semiconductor laser has advantages such as its extremely small volume, long life, and no need for a high-voltage power source.

(Problems to be Solved by the Invention) However, when this semiconductor laser is used as a light source for a barcode reader in order to downsize the device, the light wavelength of this semiconductor laser is 750 nm to 850 nll, which is in the near-infrared region. Therefore, when a stationary spot is irradiated, it can be seen with the naked eye, but if this spot is scanned at high speed, it becomes invisible to the naked eye.

For this reason, it is impossible to confirm with the naked eye the scan area that is actually being scanned on the scan plane. Additionally, since they have no vision, they may direct the laser beam directly into their mouths, which is extremely dangerous.

In view of this drawback, Japanese Patent Laid-Open Publication No. 59-172081 discloses an example in which a semiconductor laser is used but a scanning area on a scanning surface is illuminated with visible light.

However, since this device uses an incandescent lamp as the visible light emitting source, a new power supply is required, and
Because it is necessary to add a heat insulating structure between the incandescent lamp and part of the semiconductor laser to stabilize the characteristics of the semiconductor element, the advantage of small size, which is the most important feature of using semiconductor lasers, is lost. There is a risk of being exposed. In addition, since the visible light irradiation area is formed by irradiating visible light from an incandescent lamp onto the scanning area through a barcode pattern guide plate, the visible light irradiation area becomes unclear due to diffracted light from the incandescent lamp. There are also problems.

On the other hand, a configuration has also been considered in which two light emitting diodes are used instead of the incandescent lamp to irradiate both ends of the scanning area with light in the form of a spot.

However, even in this configuration, since two light emitting diodes are used, the electrical configuration may become complicated.

In addition, a recently emitted light emitting diode is used as a light source, and a visible light irradiation area in a flat and elongated shape is formed at a predetermined position on the scanning surface at a predetermined position on the scanning surface according to the scanning range of the laser beam by receiving visible light from the light emitting diode. a display imaging means for forming an image;
For example, a configuration including a cylindrical lens has been attempted. This arrangement is quite good when the distance between the display imaging means and the scanning area is short, but when the distance is long, the distance between the light source and the display coupling means is increased and the display Unless the focal length of the image forming means is long, a clear visible light irradiation area cannot be obtained, and the size of the display device becomes large.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a barcode reading device that can visually check the scanning range while scanning with laser light from a semiconductor laser, and that can simplify and downsize the device as a whole. It is on offer.

[Structure of the Invention] (Means for Solving the Problems) The barcode reading device of the present invention includes a light emitting diode and a display image forming means for receiving visible light from the light emitting diode, and a bar code reading device of the present invention includes a light emitting diode and a display image forming means that receives visible light from the light emitting diode. Equipped with display imaging means for forming an image of a flat and elongated visible light irradiation area along the scanning direction of the laser light from the semiconductor laser and corresponding to the scanning range at a predetermined position on the scanning surface on which the code is applied. However, means is formed between the light emitting diode and the display imaging means to allow only a portion of visible light having a strong light intensity distribution to pass through.

(Function) With this structure, the visible light from the light emitting diode passes through a means that only passes through the parts where the light intensity distribution is strong, and the size of the light source of the light emitting diode can be reduced by almost all the light intensity. This reduces the size of the X-direction image of the visible light irradiation area.

(Example) Hereinafter, a first example of the present invention will be described with reference to FIGS. 1 to 3.

First, in FIG. 2, reference numeral 1 denotes a semiconductor laser, and a laser beam 2 emitted from the semiconductor laser is focused into a spot having a desired diameter by a focusing lens means 3 consisting of a plurality of lenses.

Reference numeral 4 denotes a scanning reflecting means consisting of a rotating mirror such as a polygon mirror, which is rotatably provided in six directions of arrows and reflects the laser beam 2 from the semiconductor laser 1 to reflect the reflected light for scanning. A laser beam 2a is configured to scan a scanning surface 6 on which a barcode 5 is applied. In addition, in Figures 1 and 2 - 7 indicated by the dotted chain line.
is a scanning line, which indicates a scanning locus drawn on the scanning surface 6 by the scanning laser beam 2a when the scanning surface 6 moves in a direction along the scanning direction of the scanning laser beam 2a.

Now, in FIGS. 1 and 2, 8 is one or a plurality of light emitting diodes arranged in parallel in the Y direction,
Reference numeral 10 denotes a pinhole plate which is a means for passing only a portion of the visible light 9 having a strong light intensity distribution. and light emitting diode 8
The visible light 9 emitted from the light beam 9 is limited in size by a pinhole plate 10, and then focused into a visible light beam 12 having a circular cross section by a focusing lens means 11 consisting of one or more lenses. Reference numeral 13 denotes a cylindrical lens, which is a display image forming means, for example, and has a semicircular semicircular cross section as shown in FIG. 2, and has a convex curvature in the It is formed so as not to have any curvature in any direction. The cylindrical lens 13 receives a visible light beam 12 in the Z-axis direction from the focusing lens means 11 on its flat surface 13a, and outputs a visible light beam 14 for display from its curved surface 13b. Here, since the cylindrical lens 13 has a convex curvature in the X-axis direction and no curvature in the Y-axis direction, the visible light beam 14 for display is transmitted along its X-axis as shown in FIG. The directional component is focused at a predetermined focal point B (see FIG. 3(b)), and the Y
The axial component passes through and is sequentially diffused (see FIG. 3(a)). As a result, the visible light beam 12 and the visible light beam 14 for display are transferred to the cylindrical lens 1.
3, the intermediate position 16 between the cylindrical lens 13 and its focal point B, the position 17 of the focal point B, and the focal point B.
When cut along the X-Y plane at each of the far positions 18, beam cross sections 19 to 22 are presented at each of the positions 15 to 18, respectively, as shown in FIG. 3(C). Therefore, by positioning the focal point B of the cylindrical lens 13 on the scanning plane 6, a flat and elongated visible light irradiation region 23 is imaged on the scanning plane 6. Visible light beam ii here! 23 has its flat long direction along the scanning line 7 which is the scanning direction of the scanning laser beam 2a, and its dimension in the flat long direction is set to a size corresponding to the scanning range of the scanning laser beam 2a. .

Next, the function of the pinhole plate 10 will be explained.

The display imaging means 13 that receives the visible light from the light emitting diode 8 forms a visible light irradiation area 23 in a flat and elongated shape along the scanning direction of the laser beam at a predetermined position on the scanning surface 6 and corresponding to the scanning range. image.

In this case, the size of the image in the X direction of the visible light irradiation area 23 is determined by the size of the light source (light emitting diode 8) being Ha, as shown in FIG. The distance to La1 visible light irradiation area 1tL23
The size of the image in the direction is Hb.

If the distance from the display image forming means 13 to the visible light irradiation area 23 is Lb, and the focal length of the display image forming means 13 in the X direction is f, then the relationships shown in equations (1) and (2) can be obtained. It will be done.

Upper-+ Upper--1 (1) al-bf kL= -! -! ! -<2> Ha Hb Here, l, a, l-b, and f are determined by the specifications of the display imaging means 13. Therefore, X in the visible light irradiation area 23
In order to reduce the directional size Hb, it is necessary to reduce the size of the light emitting diode 8 that is the light source. On the other hand, the light emitting characteristics of the light emitting diode 8 are strong at the center and weak at the periphery, as shown in FIG. Therefore, by providing a pinhole plate 10 of a size that allows only the central portion where the light intensity distribution is strong to pass through immediately in front of the light emitting diode 8, the size Ha of the light source (light emitting diode 8) can be reduced.
can be reduced with almost no reduction in light intensity, and the size Hb of the image in the X direction of the visible light irradiation 'aVL23 can be reduced.

As a result, the scanning range of the laser beam can be clearly seen with a simple and compact configuration using a semiconductor laser and a light emitting diode.

According to this embodiment having such a configuration, the light emitting diode 8
Upon receiving the visible light 9 whose size is controlled by the pinhole plate 10, the cylindrical lens 13 emits visible light in a flat and elongated shape along the scanning direction of the laser beam 2 and corresponding to the scanning range on the scanning surface 6. Since the irradiation area 23 is configured to form an image, even if the laser beam 2 is a near-infrared laser emitted from the semiconductor laser 1, the scanning range cannot be visually recognized in the scanning state. By using the pinhole plate 10 disposed just before the light emitting diode 8, the size of the light source of the light emitting diode 8 can be reduced without substantially reducing the light intensity through only the central part where the light intensity distribution is strong. X of light irradiation area 123
The size of the directional image becomes small, and the scanning area can be easily recognized by the visible light irradiation area [23]. Furthermore, since the configuration uses the semiconductor laser 1, the entire device can be simplified and downsized. Furthermore, the configuration can be simplified compared to the conventional display system that includes two optical systems. In addition, the display visible light beam 14 is transmitted through a cylindrical lens 1.
Beam cross section 20.21 depending on the position before and after the focal point B of 3.
．． 22, the distance between the cylindrical lens 13, that is, the barcode reading device, and the scanning surface 6 can be easily set while visually checking them.

FIG. 6 shows a second embodiment of the present invention, which differs from the first embodiment in that a so-called toroidal lens 24 is used as a display imaging means instead of a cylindrical lens 13.
It is in a configuration using . As shown in FIG. 6, this toroidal lens 24 has a convex curvature in the X-axis direction and a concave curvature in the Y-axis direction. Therefore,
Although the same effects as in the first embodiment can be obtained in this second embodiment, in particular, the toroidal lens 2
4 has a concave curvature in the Y-axis direction, Y-
Components along the Z plane are more diffused. As a result, each beam cross section 26, 27, 28 of the display visible light beam 25
is formed into a more flat and elongated shape as shown in FIG. 6(c), so that a more flat and elongated visible light irradiation region can be imaged on the scanning surface 6.

FIG. 7 shows an embodiment of the present invention shown in FIG. 3. The difference from the first embodiment is that a display visible light irradiation device 29 consisting of a light emitting diode 8, a focusing lens means 11 and a cylindrical lens 13 is used. The point is that a plurality of them, for example three, are provided. In this third embodiment, the same effects as in the first embodiment can be obtained, but in particular, since three display visible light beams @ 29 are provided, each visible light irradiation area 30 is continuous. By doing so, the length of the visible light irradiation area 31 in the flat longitudinal direction can be freely set.

FIG. 8 shows a fourth embodiment of the present invention, which differs from the first embodiment in that instead of using a focusing lens means 11 and a cylindrical lens 13, an aspheric lens having both functions is used. The point is that it is configured to use a toroidal lens 32. Although the same effects as in the first embodiment can be obtained in this fourth embodiment, since the toroidal lens 32 having the functions of both the focusing lens means 11 and the cylindrical lens 13 is used, the structure can be made smaller. can be converted into

FIG. 9 shows a fifth embodiment of the present invention. The difference from the first embodiment is that a scanning laser beam 2a from a semiconductor laser 1 is scanned on a scanning surface 6, and The sharp cut filter 34 is provided in front of the light receiving element 33 that receives the reflected light 2b.

Here, the sharp cut filter 34 is configured to transmit light with a wavelength of 750 nm or more, which is the wavelength of the laser beam 2, and to block light with a wavelength shorter than 750 nm. In this fifth embodiment, the same effects as in the first embodiment can be obtained, but since a sharp cut filter 34 is provided in front of the light receiving element 33, visible light 9 from the light emitting diode 8 is received. It is possible to prevent light from being received by the element 33, and the S/N ratio of the light-receiving signal of the light-receiving element 33 can be improved accordingly.

FIG. 10 shows a sixth embodiment of the present invention, which differs from the first embodiment in that a focusing lens means 11 is provided between a light emitting diode 8 and a cylindrical lens 13.
The reason is that it is constructed by omitting the .

In this sixth embodiment, since the focusing lens means 11 is omitted, the shape of the visible light irradiation area 36 formed on the scanning surface 6 by the displaying visible light beam 35 transmitted through the cylindrical lens 13 is slightly unclear. Although it lacks, the first
It is possible to obtain substantially the same effects as in the embodiment described above, and furthermore, the structure can be made simpler and at a lower cost.

FIG. 11 shows a seventh embodiment of the present invention, which differs from the first embodiment in that a reflecting means 37 made of a mirror or prism is provided between the focusing lens means 11 and the cylindrical lens 13. The point is that it is configured like this.

In this seventh embodiment as well, the same effects as in the first embodiment can be obtained, but in addition, the optical path of the visible light beam 12 focused by the reflecting means 37 via the focusing lens means 11 is Since it is made to enter the synchronic lens 13 after being bent, it can be effectively used when a sufficient space in the Z-axis direction cannot be secured.

FIG. 12 shows an eighth embodiment of the present invention, which differs from the first embodiment in that a pinhole plate 10 is used instead of a pinhole plate 10, which is a means for passing a portion where the light intensity distribution of visible light is strong. , the surface of the light emitting diode 8 is coated with a paint that does not transmit light except for the top part 38, and the structure is simple and there is no need to align the optical axis of the light emitting diode 8 and the pinhole plate 10. be.

In each of the above embodiments, a polygon mirror is used as the scanning reflecting means 4, but the present invention is not limited to this, and a vibrating mirror such as a galvanometer mirror may be used.

[Effects of the Invention] As is clear from the above description, the present invention includes a display imaging means that receives visible light from a light emitting diode that passes through a means for passing a portion where the light intensity distribution of visible light is strong. A flat and elongated visible light irradiation area is formed along the scanning direction of the laser beam from the semiconductor laser at a predetermined position on the scanning surface on which the barcode is applied by the image forming means, and according to the scanning range. Because of this structure, while scanning with laser light from a semiconductor laser, the scanning range can be clearly seen with almost no reduction in the light intensity due to the size of the light source, and the device as a whole is easy to configure. This has an excellent effect in that it can be made smaller and smaller.

[Brief explanation of drawings]

1 to 5 show a first embodiment of the present invention. FIG. 1 is a perspective view of the main part, FIG. 2 is a perspective view, and FIG. 3 is a visible light beam and a A diagram showing the state of the visible light beam for display, Figure 4 is a diagram showing the relationship between the size of the light source in the optical system, the size of the image, and the distance from each lens, and Figure 5 is the diagram showing the light intensity distribution of the light emitting diode. It is a figure showing the relationship of dimensions. 6 is a diagram corresponding to FIG. 3 showing a second embodiment of the present invention, and FIGS. 7 to 10 are diagrams corresponding to FIG. 2 and 11 showing third to sixth embodiments of the present invention, respectively. This figure is a diagram corresponding to FIG. 1 showing a seventh embodiment of the present invention. Further, FIG. 12 is a diagram corresponding to FIG. 1 showing an eighth embodiment of the present invention. In the drawing, 1 is a semiconductor laser, 2 is a laser beam (laser light), 5 is a bar code, 6 is a scanning surface, 8 is a light emitting diode, 9 is visible light, and 10 is a pinhole plate (for controlling the light intensity distribution of visible light). 12 is a visible light beam, and 13 is a cylindrical lens (for display purposes).
m means), 14.35 is a visible light beam for display, 23.3
0, 31.36 indicates a visible light irradiation area, and 24.32 indicates a toroidal lens (imaging means for display). Agent: Patent Attorney: Nori Chika, Yudo, Hirofumi Mimata, 34 years old, 7 years old? Go 31 shi 5th (3 ba 71″″′. l Fig. 8 9! Σ

Claims (1)

[Claims] A barcode reading device that scans a scanning surface on which a barcode is applied with laser light from a semiconductor laser and reads the barcode based on the reflected light from the scanning surface includes a light emitting diode and a light emitting diode. For display, which receives visible light from a diode through a focusing lens and forms a flat and elongated visible light irradiation area at a predetermined position on the scanning surface along the scanning direction of the laser beam and corresponding to the scanning range. 1. A barcode reading device comprising an imaging means, and means for allowing only a portion of visible light having a strong light intensity distribution to pass between the light emitting diode and the focusing lens.