JPH09237314A - Symbol reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a symbol reader facilitating the positioning of a reading object and reducing reading errors. SOLUTION: Illuminating light with the wave length of red light is originated to the reading object within a reading opening part 30 from a light source 50. A part of light reflected by he reading object is reflected by a half mirror 40 and is guided to an image pickup element 81 through an image pickup optical system 70, and the remaining part passes through the half mirror 40 and is guided to a visualizing window 20. External light entered from the visualizing window 20 passes through the half mirror 40, is reflected by the reading object and is guided to the visualizing window through the half mirror 40. An operator confirms whether the reading object is perfectly housed or not in the reading opening part 30 from the visualizing window 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a symbol reading device for reading a data symbol such as a two-dimensional bar code reader.

[0002]

2. Description of the Related Art POS (Point of Sale)
s) A bar code reader used in a system or the like irradiates an object to be read with illumination light and processes the reflected light with an imaging optical system. The object to be read is a character or symbol written on paper or a container. In order to accurately read those two-dimensional data symbols, the operator should make sure that the character or symbol fits within the reading area of the barcode reader. The reader must be positioned.

[0003]

However, the conventional bar code reader has no means for confirming the state of the reading area, causing a reading error and requiring a skill in operation of the bar code reader.

As a means for solving such a problem, it is known that an opening for confirming the state of the reading area is provided in the bar code reader main body, but the opening is formed on a surface vertical to the reading area. Since the section is provided, there is a problem in that a part of the reading area is blocked by the barcode reader main body depending on the position of the operator's viewpoint, and there is a problem in operability.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a symbol reading device which can accurately confirm the position of a reading target in a reading area and can easily position the reading target and does not induce a reading error. And

[0006]

According to the present invention, an image pickup device for reading a symbol is provided, and a reading opening having a size large enough to cover the symbol and a viewing window for viewing the symbol are formed. And a split optical system that is provided between the reading opening and the viewing window and guides part of the light incident from the reading opening to the image sensor and guides other light to the viewing window. To do.

The splitting optical system guides a part of the light in the vicinity of the specific wavelength band to the image pickup element and a part of the light in the vicinity of the specific wavelength band to the visual window so that the light other than the light in the vicinity of the specific wavelength band is emitted. It may be a half mirror as it leads to the viewing window.

Further, a spectroscopic optical system may be arranged between the image pickup optical system and the splitting optical system to transmit light in the vicinity of a part of the wavelength band and not transmit light in the vicinity of the other wavelength band.

The spectroscopic optical system may be a filter that transmits only light in the vicinity of a specific wavelength band.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a symbol reading device according to an embodiment of the present invention when viewed from the side, and FIG. 2 is an overhead view when viewed from the side of a viewing window.

When the operator half-presses the trigger 92 (see FIG. 2), the light source 50 (see FIG. 1) is lit with low brightness.
The light source 50 is, for example, an LED that emits red light of 660 nm (nanometer), and the illumination light emitted from the light source 50 is diffused through the diffusion plate 51 and is positioned in the reading opening 30 provided in the housing 10. In addition, it is irradiated on the bar code written on the paper or the container to be read.

The half mirror (splitting optical system) 40 includes 66
Almost all light in the wavelength band of ± 30 nm centering on 0 nm is reflected, and almost all light in the other wavelength bands is transmitted. Therefore, 660 nm reflected by the barcode
Almost all the light in the near wavelength band is reflected by the half mirror 40 and guided to the prism 60. The half mirror 40 is specifically ± 30 with a center of 660 nm.
It is more preferable to use a half mirror that reflects about 90% or more of light in the wavelength band of nm range and transmits about 90% or more of light of other wavelength bands.

The viewing window 20 is fitted with a transparent member such as glass or acrylic. External light entering the reading device through the viewing window 20 passes through the half mirror 40 and is guided to the reading opening 30. In this external light, almost all the light in the wavelength band near 660 nm is reflected by the half mirror 40 and guided to the prism 60 in the light reflected by the bar code, and almost all the light in the other wavelength bands is in the half mirror. The light passes through 40 and is guided to the viewing window 20.

Since the operator can confirm the entire area of the reading opening 30 by the light guided to the viewing window 20 as described above, the object to be read is completely contained in the reading opening 30. It is possible to easily visually confirm whether or not there is.

That is, the reading opening 30 is viewed through the viewing window 20 and the reading target is the reading opening 30.
If it is not completely accommodated inside, the housing 10 or the reading target is moved while checking through the visual window, and the reading target is positioned within the reading opening 30. After confirming that the object to be read is completely contained in the reading opening 30 through the above operation, the trigger 92 is fully pressed.

When the trigger 92 is fully pressed, the light source 50 is turned on with a high-intensity pulse, and at the same time, the reading operation including the shutter operation in the image pickup optical system 70 is started. The illumination light of the high-intensity pulse emitted from the light source 50 is emitted to the bar code positioned in the reading opening 30 and reflected by the bar code 66, as in the half-pressing of the trigger.
Almost all light in the wavelength band near 0 nm is the half mirror 40.
Is reflected by and is guided to the prism 60. As shown in FIG. 3, the pulse width of the high brightness pulse is set so that the brightness stable section A excluding the brightness rise and fall times is at least longer than the shutter time B.

The light guided to the prism 60 is transmitted to the prism 60.
The light is focused on the image pickup optical system 70 via the lens and is focused on the image pickup element 81 by the lens group including the image pickup lens 71. Pixel signals corresponding to the optical image formed on the image sensor 81 are subjected to predetermined processing such as binarization by a processing circuit such as the imaging substrate 90 and the decoding substrate 91, and output to the control circuit.

The control circuit judges whether or not the reading is successful based on the binarized data of the pixel signal, and outputs the result to the display circuit. In the display circuit, the reading display lamp 93 is driven according to the input result from the control circuit.

The operator confirms whether or not the bar code has been correctly read based on the state of the reading display lamp 93. When the reading display lamp 93 indicates that the reading has failed, the operations from the confirmation of the bar code position through the viewing window 20 to the full pressing of the trigger are repeated.

Further, in the present embodiment, the image pickup optical system 7
A cut filter (spectroscopic optical system) that transmits only light in the wavelength band near 660 nm may be arranged between 0 and the prism 60. As a result, even when external light entering through the viewing window 20 enters the imaging optical system, light other than light in the wavelength band near 660 nm, that is, light that matches the wavelength of the light emitted from the light source 50 is blocked. It is possible to prevent adverse effects on the processing circuit.

Further, since the half mirror that reflects a part of the light matching the wavelength band of the illumination light of the light source 50 and guides it to the image pickup optical system is used, the accuracy of the reading process is high.

In the second embodiment, the half mirror 40 has about 50% of the light in the wavelength band near 660 nm.
It is also possible to use a light source that reflects light and transmits about 50%, and transmits almost all light in other wavelength bands. Other configurations are similar to those of the first embodiment. According to this embodiment, 66
Since a part of the light in the wavelength band near 0 nm can be used for visual observation, it is economical if the light source 50 is turned on with a low-intensity pulse when the trigger is half pressed.

As described above, according to both embodiments, the position of the object to be read such as the barcode in the reading opening 30 can be confirmed through the viewing window 20, so that the barcode can be accurately placed in the reading opening. It is easy to locate and does not induce read errors.

In both of the embodiments, the light source that emits red light having a wavelength band near 660 nm is used, but the light source is not limited to this, and light having another wavelength band may be emitted.

In both of the embodiments, a lamp that appeals to the operator's visual sense is used as a means for notifying the operator of the reading result, but the present invention is not limited to this, and the operator is notified of the reading result by voice. May be.

[0026]

As described above, according to the present invention, the object to be read can be easily positioned in the reading opening,
It is possible to obtain a symbol reading device with less reading error.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a symbol reading device according to a first embodiment of the present invention when viewed from the side.

FIG. 2 is a bird's-eye view of the symbol reading device as viewed from the viewing window side.

FIG. 3 is an illumination time chart.

[Explanation of symbols]

 10 Case 20 Visual Window 30 Reading Aperture 40 Half Mirror 50 Light Source 51 Diffuser 60 Prism 71 Imaging Lens 81 Imaging Device 92 Trigger 93 Reading Indicator Lamp

Claims (5)

[Claims] 1. A housing provided with an image sensor for reading a symbol, having a reading opening having a size large enough to cover the symbol, and a visual window for visually observing the symbol, And a splitting optical system that is provided between the reading opening and the viewing window and guides a part of the light incident from the reading opening to the image sensor and the other light to the viewing window. Symbol reader. 2. The splitting optical system guides a part of light in the vicinity of a specific wavelength band to the image sensor, and guides a part of light in the vicinity of the specific wavelength band to the visual window, The symbol reading device according to claim 1, wherein light other than light in the vicinity is guided to the viewing window. 3. The symbol reading device according to claim 2, wherein the split optical system is a half mirror. 4. A spectroscopic optical system is provided between the image pickup optical system and the splitting optical system so that light in the vicinity of a part of the wavelength band is transmitted and light in the vicinity of the other wavelength band is not transmitted. The symbol reading device according to claim 2, wherein: 5. The symbol reading device according to claim 4, wherein the spectroscopic optical system is a filter that transmits only light in the vicinity of the specific wavelength band.