JPS5823292B2 - Koteisukiyanasouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a fixed scanner that recognizes barcode information by scanning a light beam onto the barcode label and detecting the reflected light while moving the product to which the barcode label is attached. This device is designed to be able to read even barcode labels attached to deep recesses.

FIG. 1 shows a principle diagram of a conventional fixed focus type fixed scanner device.

1 is a transparent glass plate for determining the scanning position of the product, 2 is a laser beam oscillation device, and the oscillated laser source 2
The person is focused by a lens system 3, vibrated by a vibrating mirror 4, and focused near the glass plate 1.

5 indicates the product, and 5a indicates the Tahar code label affixed to the product.

An example of the barcode label 5a is shown in FIG. 2a.

Product 5 is moved as shown by arrow 5A, and laser beam 2A
is assumed to be scanned in a direction perpendicular to the arrow.

6 is a photomultiplier that detects the light reflected by the barcode label.

Note that the spot at the focal point of the laser beam is configured to be smaller than at least the minimum width of the barcode.

The figure shows the output when the barcode label 5a is scanned in the direction of the laser beam 2A shown in FIG. 2a.

In FIG. 2, the solid line shows the case where the product 5 is moved so that the barcode label is scanned at the focal point of the laser beam, and the dotted line shows the case where it is scanned at a position shifted from the focal point.

That is, if a barcode label is read at an out-of-focus position, the resolution will be poor.

Therefore, when the output of the photomultiplier 6 is used to discriminate between black and white bars on a barcode label, discrimination becomes impossible if the focus is shifted further than the connecting position.

That is, when a barcode label is attached to the recessed part of the product 5, there is a drawback that it becomes difficult to read the barcode label.

The present invention aims to improve this drawback, and one embodiment thereof is shown in FIG.

1 to 6 are the same as the above-mentioned components, and 7 moves the lens system 3 that focuses the laser beam 2A at a constant period in the optical axis direction to change the position of the focal point connected to the glass plate 1. This is a drive device that does this.

Here, if the vibration speed of the vibrating mirror 4 is made sufficiently faster than the moving speed of the product 5, the barcode label 5a will be exposed to the laser beam 2A several to several dozen times for one scan of the product 5.
will be scanned.

However, even if scanned several dozen times at out-of-focus positions (positions with poor resolution), it is impossible to distinguish between black and white barcodes.

Therefore, in this embodiment, the lens system 3 is moved so that the depth of focus is changed during these several dozen scans so that the scan is performed at least once at or near the focused position.

Next, an example will be given and explained. FIG. 4 shows the position of the focal point with respect to time, and shows the time interval at which the barcode label 5a is scanned Δt1 to Δt7, and the figure shows that the barcode label 5a is scanned seven times.

hl indicates the position of the focal point from the initial glass surface scanned at Δt1, and indicates that it changes to h2 at the end of Δt1.

Thereafter, the lens system 3 is driven by the driving device 7, and the focal point position is changed from h2 to h3 within one scan. h3～゛h4...
...and the smell changes as Δti (however, i is 1≦i≦
Even if the diameter of the spot changes due to a shift in focus within the range (an integer of 7), the change in diameter will be within the width of the barcode and the barcode can be identified. There is.

With this configuration, the reading condition is satisfied at any one of Δt1 to Δt7, and information read at an appropriate Δt (where j is an integer of 1≦j≦7) is extracted from the seven scans. , performs barcode discrimination.

That is, if the reading depth when the lens system 3 is fixed is δ in the figure, it becomes α in the figure in the present invention, and the apparent reading depth becomes large.

As described above, the present invention is configured to scan a light beam onto the barcode label while moving the product to which the barcode label is attached, detect the reflected light, and recognize the information on the barcode label. By configuring the focus of the light beam that scans the barcode label to change at a constant cycle within a range where the amount of movement of the focus within the scan does not affect the identification of the barcode label, it is possible to Even when the label is attached, the information on the label can be completely read, and the effect is unique.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional fixed scanner device, Figure 2a,
b is an explanatory diagram of its operation, FIG. 3 is a block diagram of a fixed scanner device in an embodiment of the present invention, and FIG. 4 is an explanatory diagram of its operation. 2...Laser beam oscillation device, 3...Lens system, 4...-Vibration mirror, 5-...Product, 5
a... - Barcode label, 6... Photomultiplier, 7... A - Drive device.

Claims (1)

[Scope of Claims] 1. A light beam is scanned onto the barcode label while the product to which the barcode label is attached is moved, and the reflected light is detected to recognize the information on the barcode label. , the amount of movement of the focus of the light beam that scans the barcode label within one scan is the barcode. A fixed scanner device characterized in that it changes at a constant cycle within a range that does not affect label discrimination.