JPS61239375A - Bar code scanner - Google Patents

Abstract

PURPOSE:To improve the light utilizing efficiency of a bar code scanner, by providing a lighting light source outside of an image forming luminous flux path on the image side of an image forming lens and a mirror which reflects a luminous flux obliquely passing through the lens toward a bar code reading area. CONSTITUTION:A lighting light source 1 is provided outside the optical path of an image forming luminous flux on a photodetecting element 4 of an image forming lens 2. The light of the light source 1 is obliquely passed through the image forming lens 2 and reflected by a mirror 12, and then, condensed to the reading area 9 of a bar code tag 8 after coming out from the front end opening of a scanner housing 10. The reflecting luminous flux from the reading area 9 of the bar code tag 8 is passed through an aperture 3 and forms an image on the photodetecting element 4 after passing through the lens 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes an illumination light source, an imaging lens, and a light receiving element provided at the imaging position, and is moved relative to a barcode to illuminate the barcode. The present invention relates to a barcode scanner that scans and reads barcodes with a light receiving element.

Recently, barcodes have become widely used as a means of product management, such as product sales and inventory.

To read barcodes, a pen-shaped scanner is manually moved over the barcode of a product that is placed still, and a light source installed in the scanner scans the barcode, and the reflected light is reflected by an imaging lens installed in the scanner. There are methods to read barcodes by forming an image on a light-receiving element, and methods to read barcodes by moving the product relative to a fixed scanner, but both methods involve moving the scanner and barcode relative to each other to read and scan them. They are the same in terms of what they do.

A typical configuration of a conventional barcode scanner is shown in Figure 2 (
), an optical system housing 11 having an imaging lens 2 is provided in a pen-shaped scanner housing 10,
The scanner housing To and the optical system housing 11 have open ends, and a light emitting element 1 such as an LED provided outside the optical system housing opening illuminates a part of the barcode tag 8 through the scanner housing opening. The reflected light passes through the opening of the scanner housing 10 and the opening of the optical system housing 11, is converged by the imaging lens 2, is emitted from the aperture 3 provided at the opposite end of the optical system housing 11, and is sent to the light receiving element. The image is formed on 4, scanned by moving a scanner, and converted into an electric signal by an electric circuit 7, which is then read. In this case, the range of the barcode to be imaged on the light receiving element 4 at a certain point, that is, the reading area is the range 9 in the barcode tag 8, as shown in FIG. It is necessary to irradiate with high illuminance. However, in the scanner shown in FIG. 2(a), the light emitted from one light emitting element l spreads over a much wider range than the solid angle θ required to illuminate the reading area 9, and the light utilization efficiency is extremely low. In other words, it was necessary to extremely increase the amount of light from the light emitting element.

In order to improve this point, as shown in FIG. 2(C), the light emitting element 1 is provided at a position shifted from the optical axis on the vernied side of the imaging lens 2, with the lens facing toward the lens, and the emitted light beam is After passing through the imaging lens 2, the light is reflected by a mirror 5 with a hole 5a in the center, passes through the imaging lens 2 again, and is focused on the reading area 9 of the barcode tag 8, and the reflected light is A scanner has been proposed in which an image is formed by passing through a lens 2, passing through a hole 5a of a mirror 5, and forming an image on a light receiving element 4. This configuration considerably improves the light usage efficiency of one light emitting element compared to the previous one, but since the area of the imaging lens is divided between the illumination side and the imaging side, the illumination light passing through the center of the lens cannot be read. Since the light is not used for illuminating the area, and the light reflected from the barcode passing through the lens periphery is not received by the light receiving element, the overall light utilization efficiency is also low.

OBJECT The present invention aims to provide a barcode scanner that eliminates the above-mentioned drawbacks of conventional barcode scanners and has high light utilization efficiency.

Structure In order to achieve the above-mentioned object, the present invention provides an illumination light source on the image side of the imaging lens outside the optical path of the imaging light beam, and directs the light beam emitted from the illumination light source and obliquely transmitted through the imaging lens into the barcode reading area. The feature is that a mirror is provided to reflect the light toward.

EMBODIMENT OF THE INVENTION Below, this invention is demonstrated in detail based on the drawing which shows the Example.

FIG. 1 is a diagram showing an embodiment of the present invention, in which an illumination light source 1
is provided in a position with respect to the imaging lens 2 that does not overlap the optical path of the imaging light beam (dotted area in the figure) on the side of the light receiving element 4, with its light emitting surface facing the lens, and is emitted from this light source 1. The light beam that has passed obliquely through the imaging lens 2 is sent to the scanner housing 10.
A mirror 12 is provided so that the light exits from the opening at the tip and focuses on a predetermined reading area 9 of the barcode tag 8. The reflected light beam from the reading area 9 of the barcode tag 8 exits from the aperture 3 at the rear end of the optical system housing 11 by the lens 2, forms an image on the light receiving element 4, is converted into an electric signal by an electric circuit, and is read. The points are the same as before.

Since the barcode scanner is configured as described above, among the light beams emitted from the illumination light source 1, the light source in the range of the solid angle α that is incident on the imaging lens 2 is the light source that is incident on the imaging lens 2. mirror 1
2 to illuminate the reading area 9 on the barcode tag 8,
All of the reflected light flux from the reading area that enters the imaging lens 2 forms an image on the light-receiving element 4, so the light utilization efficiency is the second
This is much improved compared to those shown in Figures (a) and (C), and conversely, it is possible to reduce the amount of light from the light source and the aperture of the lens, making it more compact.

As shown in FIG. 3 (,a''), when the illumination light source 1 is moved away from the lens 2, its image formation position approaches the scanner tip, and conversely, when the illumination light source 1 is brought closer to the imaging lens 2, its image formation position The position moves away from the tip of the scanner. Also, by changing the position of the mirror 12 and its angle with respect to the optical axis, the position of the irradiation area on the barcode tag can be changed. position,
If the angle with respect to the optical axis can be changed arbitrarily using a slider or the like provided on the outside of the scanner housing 10, the operator can illuminate the barcode tag with the scanner, move the slider while looking at the light spot, and read the barcode. The desired position on the tag can be easily modified to the desired optical spot diameter. In this case, it goes without saying that the illuminance of the reading area on the barcode surface should not fall below the required absolute illuminance, and that the depth of focus of the imaging lens necessary for reading should be sufficient.

As described above, according to the present invention, much of the light emitted from the illumination light source can be efficiently irradiated onto the reading area of the barcode tag surface, and the required light amount of the light source and the aperture of the lens can be reduced. This is effective in reducing the size and cost of the scanner.

Note that the present invention can be applied not only to a type of barcode scanner in which the scanner is moved, but also to a type of barcode scanner in which the scanner is fixed and an article with a barcode tag attached thereto is moved and scanned. .

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2(a) is a sectional view showing an example of a conventional scanner, and FIG. 2(b) is a perspective view illustrating how the light source from the illumination light source is used. (C) is a sectional view showing another example of a conventional scanner; FIG. 3(a);
(b) is a sectional view showing another embodiment of the present invention. 1... Light emitting element (illumination light source) 2... Imaging lens 4... Light receiving element 8... Barcode 9... Barcode reading area 12... Mirror Fig. 2 (a) (b) ) Figure 2 (C) Figure 3 (b)

Claims (1)

[Claims] It has an illumination light source, an imaging lens that forms an image of the barcode reading area illuminated by the illumination light source, and a light receiving element provided at the imaging position. In a barcode scanner that scans the code with illumination and reads the barcode with a light-receiving element, the above-mentioned illumination light source is provided on the image side of the above-mentioned imaging lens outside the optical path of the imaging light beam, and the light is emitted from the illumination light source, and the above-mentioned A barcode scanner comprising a mirror that reflects a beam of light obliquely transmitted through an image lens toward a barcode reading area.