JPS62192881A - Bar code reading device - Google Patents

Abstract

PURPOSE:To prevent suppression of the readable range of a distance between a bar code reading device and a bar code can be read by making a laser light into the parallel light having a small light flux with a concave mirror and a convex mirror, and making the parallel light into a scanning light. CONSTITUTION:The laser light generated by a laser light generating device 11 is reflected and converged by a concave mirror 12. At the position where the light flux diameter of the reflecting light of the concave mirror 12, a convex mirror 13 is placed. The curvature of the concave mirror 12 and the convex mirror 13 is set so that the reflecting light of the convex mirror 13 goes to a parallel light. The reflecting light of the convex mirror 13 comes to be the scanning light and deflected by plane mirrors 14 and 15 and scans a bar code label 21. The disturbance light from the bar code level 21 is converted to an electric signal by a photosensitive device 16 and bar code data are outputted from a bar code decoding part 17.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a barcode reading device, and more particularly to a barcode reading device that uses a laser beam as a scanning light. [Prior Art] A laser beam has a small beam diameter. It is often used as a light source for scanning light in bar code reading devices.

FIG. 2 is an optical path diagram showing scanning light of an example of a conventional barcode reading device.

The conventional barcode reading device shown in FIG.
The light was converged to form scanning light 105. The scanning light 105 is deflected by a scanning optical system (fc, omitted in FIG. 2) to completely scan the barcode (omitted in FIG. 2) near the focal point F. The barcode reflects diffusely and the intensity of the scattered light changes depending on the blackness and whiteness of the barcode. This intensity change sound and light sensor converts the intensity change into an electrical signal, and the barcode is read based on this electrical signal.

The beam diameter of the scanning light 105 is minimum at the position of the focal point F, and increases as it moves away from this position.0 As the beam diameter of the scanning beam 105 increases, the resolution decreases, so the minimum line of the barcode Required resolution corresponding to width? In order to obtain this, the beam diameter of the scanning light 105 needs to be less than or equal to a required value corresponding to the minimum line width of the Nokuichi code. For this reason, in conventional barcode reading devices, it was necessary to place the barcode within a range where the beam diameter of the scanning light 105 was less than or equal to a required value.[Problem to be Solved by the Invention 3] Traditional barcode reading devices are
Laser light [1-Since scanning light is obtained by converging it with a lens, barcodes can only be read near the focus of the scanning light,
There is a drawback that the readable range of the distance between the barcode reading device and the barcode is limited.

SUMMARY OF THE INVENTION An object of the present invention is to provide an entire barcode reading device that overcomes all of the above-mentioned drawbacks and has no restrictions on the readable range.

[Means for solving problems]

The barcode reading device of the present invention scans the entire barcode attached to an object by optically manipulating a laser beam, and detects the intensity of the scattered light of the scanning light that is diffusely reflected by the barcode. Converts the strength of the electrical signal using a device,
In a barcode reading device that reads the barcode based on this electrical signal, a concave mirror that reflects and converges the laser beam, and a concave mirror placed at a position where the beam diameter of the reflected light of the concave mirror becomes small, are used to detect the reflected light. [Example] The following is carried out! The invention will be described in detail with reference to the drawings shown in l'(r).

FIG. 1 is a block diagram showing an embodiment of the inventive barcode reading device.

In FIG. 1, reference numeral 1 indicates a barcode reading device according to an embodiment of the present invention, and 2 indicates an object to which a barcode label 21 on which a barcode to be read is printed is attached. 0 Barcode reading device #1・Laser beam generator 11
, a concave mirror 12 , a convex mirror 13 , a plane mirror 14 for horizontal scanning, a plane mirror 15 for vertical scanning, a photodetector 16 , and a barcode decoder 17 .

FIG. 3 is an optical path diagram of a portion surrounded by a broken line in FIG. 1.

As shown in Fig. 3, a laser beam generated by a laser beam generator 11 is reflected by a concave mirror 12 and converged. A convex mirror 3 is placed at a position where the beam diameter of the reflected light from the concave mirror 12 becomes small. The curvatures of the concave mirror 12 and the convex mirror 13 are set so that the reflected light from the convex surfaces # and 13 becomes parallel rays. With this setting, the scanning light 101 that is the reflected light from the convex mirror 130 becomes a parallel light beam with a small luminous flux diameter.

The plane mirror 14 makes an oscillating motion to deflect the scanning light 101 in the horizontal direction, and the plane mirror 15 makes an oscillating motion to deflect the scanning light 101 in the vertical direction. The scanning light 101 is thus deflected by the plane mirrors 14 and 15 and scans the barcode label 21'.

The intensity of the scattered light 102 diffusely reflected by the barcode label 21 changes depending on the blackness and whiteness of the barcode. The photodetector 16 converts changes in the intensity of the scattered light 102 into changes in the intensity of a signal 103, which is an electrical quantity. The barcode decoding unit 17 receives the signal 1030
The barcode label 104 is output by decoding all the strength changes.

Since the scanning light 101 is a parallel light beam, the beam diameter of the scanning light 101 on the surface of the barcode label 21 remains small regardless of the distance between the object 2 and the barcode reading device 1. Therefore, object 2 and barcode reader It
Even if the distance to 1 changes, the resolution will not drop and the barcode will not be readable.

[Effects of the Invention] As explained in detail above, the barcode reading device i of the present invention uses a concave mirror and a convex mirror to convert a laser beam into a parallel beam with a small beam diameter, and converts this parallel beam into a scanning beam. Therefore, even if the distance to the barcode changes, the beam diameter of the scanning light remains small, and the resolution does not decrease, resulting in the effect that the range of barcode reading 5J is restricted.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the barcode reading device of the present invention, FIG. 2 is an optical path diagram showing scanning light of an example of a conventional barcode reading device, and FIG. 3 is the same as that shown in FIG. FIG. 2 is an optical path diagram of a portion surrounded by broken lines in FIG. 1... Barcode reading castle V binding, 11...
...Laser beam generator, 12...Concave mirror, 13
...Convex glare, 16... Former sensor, 17
...Barcode decoding section, 21...Pal code label.・De-

Claims (1)

[Scope of Claims] A barcode attached to an object is scanned with scanning light obtained by optically manipulating a laser beam, and the intensity of the scattered light of the scanning light, which is diffusely reflected by the barcode, is detected as an electrical signal by a photodetector. A barcode reading device that reads the barcode based on this electrical signal includes a concave mirror that reflects and converges the laser beam, and a position where the beam diameter of the reflected light of this concave mirror becomes small. A barcode reading device, comprising: a convex mirror placed on the mirror to reflect the reflected light into the scanning light, which is a parallel light beam having a small luminous flux diameter.