JPH06124361A - Method for light projection of bar code reader - Google Patents

Abstract

PURPOSE:To effectively preclude a defect in reading and a failure in reading due to regular reflection. CONSTITUTION:A couple of left and right (upper and lower) light sources 11 and 12 which slant to each other are provided at a projection opening 4A, and only the left (Lower) or right (upper) light source 11 is turned on; and the information is securely read in one excellent lighting state. Consequently, the defect in reading due to regular reflection can be evaded even for, for example, a bar code symbol positioned in the regular reflection area of the bar code reader.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code reader for optically reading bar code symbols, and in particular, an unreadable area is generated due to excessive intensity of light projected from a light source. The present invention relates to a method of projecting a bar code reader for preventing it.

[0002]

2. Description of the Related Art A bar code reader for optically reading a bar code symbol written on a bar code label has been developed and used. Usually, this bar code reader is equipped with a light projecting section using a light emitting diode (LED) or the like,
The reading light is projected toward the barcode label.

[0003]

Usually, the reading light emitted from the light projecting portion is set in a fixed direction, and for example, as shown in FIG. 4, the reading light α emitted from the light projecting portion (not shown).
Light β that is specularly reflected and returned by the barcode label 100
In addition, the light intensity of the light in the vicinity thereof may be too high. As a result, there is a case where the difference in black and white contrast disappears and the image becomes unreadable, which is a serious problem especially in a stationary bar code reader. Therefore, in view of the above circumstances, an object of the present invention is to provide a method for projecting a bar code reader capable of effectively preventing the occurrence of troubles such as reading failure and unreadableness due to regular reflection. .

[0004]

That is, according to the present invention, in a bar code reader in which a pair of light sources are provided in a tilted manner in the vicinity of a light projecting port, the light sources are turned on one by one.

[0005]

According to the present invention, the pair of left and right light sources provided in the light projecting port are turned on one by one, that is, only the left side or the right side is turned on independently, and whichever is the better lighting state. This makes it possible to read the information reliably. As a result, it becomes possible to avoid reading information that may cause a reading error due to specular reflection even for a bar code symbol in the specular reflection area, for example.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an optical system of a bar code reader to which the light projecting method of the present invention is applied.
This optical system includes a light projecting unit 1 including a pair of left and right light sources 11 and 12, and a light receiving unit 2 using a CCD (charge coupled device) 21.
It consists of and. In the figure, reference numeral 3 indicates a bar code label. The light sources 11 and 12 are three LEDs each.
(LED assembly) is used, and it is provided in the housing 4 in the vicinity of the light projecting port 4A at symmetrical positions inclined in the opposite directions by the same angle.

Next, a light projecting method using the optical system of the bar code reader according to this embodiment will be described. In this embodiment, a stationary type bar code reader will be described as shown in FIG. 2, but a handy type bar code reader that can be operated with one hand is also applicable. In the light projecting method according to this embodiment, for example, in FIG. 2, the packaging box 6 to which the barcode label 3 is attached is conveyed by the conveyor belt 7. And optical sensor 5A
When it is detected that the packaging box 6 has been transported, the left and right light sources 11 and 12 are simultaneously turned on by a signal output from a control unit (not shown) → the right (left) light source 11 (1
Only 2) → the left (right) light source 12 (11) only is lit, and three types of flash lighting operations are sequentially repeated. Then, when the light receiving section 2 accurately reads the bar code symbol, the control signal from the control section stops outputting, whereby the reading operation for the bar code label is completed. When the bar code label cannot be accurately read due to stains or the like, the lighting operation is stopped by detecting that the packaging box 6 has passed the optical sensor 5B.

Therefore, according to this embodiment, for example, FIG.
In the above, when the barcode label 3 is in the posture of the solid line position, the reading failure due to specular reflection can be prevented by performing the lighting operation of only one of the left and right light sources 11 and 12. Further, at the position of the broken line, no reading failure due to specular reflection occurs when the light source 11 is turned on,
Accurate and reliable information reading can be performed. In this embodiment, a pair of left and right light sources are provided in the housing, but light sources 11 'and 12' may be provided above and below in the housing 4'as shown in FIG.

[0009]

As described above, according to the present invention, since the pair of right and left light sources which are inclined with respect to each other are turned on one by one, reliable reading of information can be ensured depending on which lighting condition is better. In other words, it is possible to read information by using the reading light that does not cause specular reflection on either the left or right side, which makes it possible to reliably read information and improve reliability. Greatly improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an optical system to which the present invention is applied.

FIG. 2 is a perspective view illustrating a projection method of the present invention.

FIG. 3 is a schematic configuration diagram showing a modified example.

FIG. 4 is an explanatory view showing a conventional defect.

[Explanation of symbols]

 1 Light emitting unit 2 Light receiving unit 3 Bar code label 4 (Bar code reader) housing 11, 12 Light source

Claims (1)

[Claims] 1. A bar code reader in which a pair of light sources are provided in a tilted manner in the vicinity of a light projecting port, wherein the light sources are turned on one by one.