JP2767412B2 - Code reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a code (one-dimensional bar code, two-dimensional code) reading apparatus, and more particularly to reading a code displayed on a material which is hardly diffusely reflected, such as a transparent wrapping paper or a mirror material. The present invention relates to a code reader.

[0002]

2. Description of the Related Art Codes (one-dimensional codes (bar codes) and two-dimensional codes) are displayed on various products, and the codes are read through a known code reading device shown in FIG. Managing. In the code reading device 30, the light source 31 directly irradiates the code 32, and the reflected light is received by a camera (CCD sensor or the like) 35 through a light entrance stop mechanism 33 and a lens 34 to decode the code information. It is carried out.

[0003]

The above-mentioned conventional code reading apparatus can read a code printed on a paper or the like which is irregularly reflected, but reads a code displayed on a transparent wrapping paper which is hardly diffusely reflected with halation. Is difficult.
Further, it is difficult for a conventional code reader to read information of a one-dimensional code or a two-dimensional code (mirror code) marked on a mirror material such as a medical instrument, a semiconductor wafer, or a metal tool due to specular reflection. Therefore, the present invention
It is an object of the present invention to provide a code reading device capable of reading both information of a code displayed and a code of a mirror surface on a material having irregular reflection such as paper.

[0004]

According to a first aspect of the present invention, a code reader irradiates a code with a light source installed in a reading case.
The reflected light of the code is read by a camera via a lens, and the code can be radiated through at least one of a diaphragm mechanism surface or an inner peripheral surface of a reading case capable of irregularly reflecting irradiation light of a light source body, and reading is performed. The normal of the mouth is formed to be inclined with respect to the optical axis of the camera. This code reading device can indirectly irradiate a code, and the normal of the reading surface is formed to be inclined with respect to the optical axis of the camera, so that the image of the light entrance hole of the light entrance diaphragm mechanism is not mapped on the camera. In this case, information can be read even with a mirror-finished code in addition to a code that does not cause irregular reflection.

According to a second aspect of the present invention, a code reader irradiates a code with a light source provided in a reading case, and reads a reflected light of the code by a camera through a lens having a light entrance diaphragm mechanism. A translucent mirror plate is provided between the lens and the reading port surface in an inclined manner, the light source body is a plane luminous body that emits diffused light, and the plane luminous body is attached so as to be able to irradiate the translucent mirror plate. . Through this translucent mirror plate, information can be read even with a mirror code displayed on a mirror-reflective material. According to a third aspect of the present invention, there is provided a code reading device, wherein a light absorbing plate is provided at a position opposite to the plane light emitter with respect to the translucent mirror plate. Code information can be read.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) In this embodiment, in addition to a code (one-dimensional code (bar code), two-dimensional code) displayed on a material that irregularly reflects, a primary code displayed on a mirror surface code (a mirror material that reflects specularly) is used. This is a code reader that can read the original code or the two-dimensional code). FIG. 1A is a cross-sectional view of a main part showing the concept of the code reader 1, and shows a case body 1a.
And an extended reading case 5 are integrally formed, and a camera (CCD sensor, imaging tube, etc.) 4 is provided in the case body 1a.
And one lens 3 are arranged, and the reading opening surface 5a of the lens 3
On the side, a light entrance stop mechanism (slit) 7 that forms a light entrance hole 7b is formed so that the readable range corresponds to the reading opening surface 5a. Note that the lens 3 is desirably disposed close to the light entrance stop mechanism 7 so as not to be affected by the image of the light entrance hole 7b.

Both the aperture mechanism surface 7a except the light entrance hole 7b of the light entrance aperture mechanism 7 and the inner peripheral surface 5b of the reading case 5 are scattered bright colors such as white or bright colors containing a fluorescent dye. It has been given. A light source 2 (2a, 2b) is installed in the reading case 5 at the end of the case body. The light source body 2 (2a, 2b) is provided on the stop mechanism surface 7a of the light input stop mechanism 7 and the inner peripheral surface 5b of the reading case 5. The reading port surface 5a is illuminated indirectly by reflected light from the aperture mechanism surface 7a and the inner peripheral surface 5b by the light source body 2 to illuminate the code 32. The light source body 2 has a plurality of LEDs arranged in a bar shape with a row of light sources or the like. The code 32 may be configured so as not to be directly illuminated by the light sources 2a and 2b. Therefore, at least one of the aperture mechanism surface 7a and the inner peripheral surface 5b of the reading case 5 can be irregularly reflected to illuminate the reading opening surface 5a. do it.
The normal line of the reading port surface 5a is formed to be inclined (angle α) with respect to the optical axis of the camera 4;
3 ゜ is desirable. Further, it is desirable that the shape of the light entrance hole 7b be a rectangle rather than a circle because the amount of incident light increases even if the inclination angle α is small.

FIG. 1B shows another code reader, which differs from FIG. 1A in that the light sources 2a and 2b irradiate the aperture mechanism surface 7a of the light entrance aperture mechanism at right angles. There is
The code is illuminated in the same manner as in FIG.

FIG. 1C shows another code reading device. The difference from FIG. 1A is that a flat light emitting body 11 for emitting diffused light is attached to the reading opening surface 5a adjacent to the lens 3. The point is that the reading port surface 5a is irradiated, and a light entrance hole 11a is formed at the center of the planar light emitting body 11. That is, this is a point in which the plane light emitter 11 is attached instead of the light source body 2, and the code is directly irradiated by the plane light emitter 11. In addition, as the plane light-emitting body 11, diffused light is obtained by electroluminescence,
Liquid crystal is illuminated by a backlight to obtain diffused light, LED
It is possible to irradiate the reading port surface 5a with the diffused light, such as to obtain the diffused light through the frosted glass.

Next, a description will be given of the reading device for each code having the above-described structure and the inclined shape of the reading opening surface 5a, particularly reading of information of a mirror code (one-dimensional code, two-dimensional code).

(A) Reading device for each code (FIG. 1A)
1 (C)), the reading port surface 5a is formed so as to be inclined with respect to the optical axis of the camera 4. First, in the code reading device (FIGS. 1 (A) to 1 (C)), reading is performed. The case where the normal line of the mouth surface 5a is formed horizontally with respect to the optical axis of the camera (sensor or the like) 4 will be described. When the horizontal reading opening surface 5a of the code reading device is applied to the code 32 displayed on a material such as paper which does not reflect specular reflection, the code 32 is indirectly irradiated by the light sources 2a and 2b, and the light input hole of the light input stop mechanism is provided. The image 3 'of the lens by the lens 7b (or the light entrance hole 11a) is mapped on the camera 4, but since the image 3' is low enough not to affect the decoding of the code, it is not possible to read the information of the mirror surface code. it can. However, specular code (specularly reflective code)
, The lens image 3 ′ (black image) due to the light entrance hole 7 b (or the light entrance hole 11 a) affects, so that “white” is interpreted as “black” and the mirror surface code information is misread. (Fig. 2
(A)).

(B) In order to prevent the lens image 3 ′ caused by the light entrance hole 7 b (or the light entrance hole 11 a) from affecting the mirror surface code, FIGS. As shown, the normal line of the reading port surface 5a is formed in an inclined shape (inclination angle α) with respect to the optical axis of the camera 4. With this configuration, the light entrance hole 7b (or the light entrance hole 11a) mapped to the camera 4 is formed.
Is mapped to a position that does not affect the mirror code image, and can be read accurately without affecting the mirror code information (FIG. 2B). As described above, the code reading device shown in FIGS. 1A to 1C can read a mirror code, but it is needless to say that a code displayed on a paper or the like that reflects irregularly can also be read. .

(Second Embodiment) In this embodiment, the lens image 3 'formed by the light entrance hole 7b (or the light entrance hole 11a) does not affect the mirror code image. This is another configuration. FIG. 3 shows a cross section of a main part of the code reader 1 of the present embodiment. A camera (CCD sensor, image pickup tube, etc.) 4 and one lens 3 are arranged in a case main body 1a. A light entrance hole 7b is provided on the mouth surface 5a side.
The light entrance diaphragm mechanism (slit) 7 is formed on the inner periphery so that the readable range corresponds to the reading surface 5a.
Since the lens 3 does not affect the image of the light entrance 7b, it is not necessary to arrange the lens 3 close to the light entrance stop mechanism 7. The translucent mirror plate 20 is provided so that the reading aperture surface 5a is inclined and closed so as to block the light entrance aperture mechanism 7 and prevent dust from entering the lens 3. The inclination angle is desirably 45 °.
The transmittance is most preferably 50%. In addition, this translucent mirror plate 2
Although there are various methods for forming 0, one example is described in which a metal such as silver is vapor-deposited on a transparent glass plate.

A flat illuminant 21 having a uniform illumination light intensity density is mounted in the reading opening surface 5a so as to irradiate the translucent mirror plate 20. In addition, as this plane light-emitting body 21, a diffused light is obtained by electroluminescence, a diffused light is obtained by irradiating a liquid crystal with a backlight, a diffused light is obtained by illuminating an LED through frosted glass, or the like. The translucent mirror plate 20 can be irradiated with diffused light. The surface of the planar light emitting body 21 is formed so as to be capable of irregular reflection. On the other hand, the light absorbing plate 2
It is desirable, but not absolutely necessary, to attach 2 to the translucent mirror plate 20 at a position opposite to the plane light-emitting body 21 because it absorbs light passing through the translucent mirror plate 20 and prevents the influence of reflected light.

Next, the operation of the code reader having the above structure will be described. The light amount from the plane light emitter 21 enters the translucent mirror plate 20, and half of the light amount is reflected to irradiate the mirror code, and the light amount is reflected. Is absorbed by the light absorbing plate 22 to eliminate the influence of the reflected light. The light illuminating the mirror surface code 32 becomes reflected light having code information and enters the translucent mirror plate 20, and half of the incident light amount reaches the camera 4 through the lens 3, The remaining light amount reaches the plane light emitter 21. As a result, the amount of light reaching the camera 4 is １ ／ or less of the amount of light from the plane light emitter 21. Therefore, when the code reading device reads the mirror code 32, the lens image 3 ′ by the light entrance hole 7b (or the light entrance hole 11a) can be read to such an extent that the information of the mirror code is not affected. As described above, it is needless to say that this code reading device can read a mirror code, and can also read a code displayed on a paper or the like that reflects irregularly.

The reflected light having the code information reaches the plane light-emitting body 21 via the translucent mirror plate 20, but since the plane of the plane light-emitting body 21 is formed as an irregular reflection surface, the plane light-emitting body 9 In this case, it is preferable that the surface of the planar light-emitting body 21 is formed as a diffuse reflection surface, since the uniformity of the illumination light density is not disturbed. Further, it is preferable to provide the light absorbing plate 22 because the influence of the reflected light can be eliminated.

[0017]

According to the code reading device of the first aspect of the present invention, the reading surface is formed to be inclined with respect to the optical axis of the camera and has a simple structure in addition to the code displayed on paper or the like. You can also read the code information. According to the code reading device of the second and third aspects, by reducing the amount of light entering the camera via the translucent mirror plate, it is possible to read not only the code displayed on the paper but also the information of the mirror code. .

[Brief description of the drawings]

FIG. 1 is a main part sectional view showing the concept of a code reading device according to a first embodiment.

FIG. 2 is a diagram illustrating the operation of the code reading device.

FIG. 3 is a main part sectional view showing the concept of a code reading device according to a second embodiment.

FIG. 4 is a main part sectional view showing the concept of a conventional code reader.

[Explanation of symbols]

 2a, 2b Light source body 3 Lens 4 Camera (CCD sensor, etc.) 5a Reading opening surface 5b Inner peripheral surface of reading opening 7 Light entrance stop mechanism 7a Stopping mechanism surface 7b, 11a Light entrance hole 20 Translucent mirror plate 21 Flat light emitter 22 Light Absorbing plate

Claims (3)

(57) [Claims] 1. A code reader for irradiating a code with a light source body installed in a reading case and reading a reflected light of the code with a camera via a light entrance diaphragm mechanism and a lens, wherein the irradiation light of the light source body is provided. The code can be radiated through at least one of the diaphragm mechanism surface or the inner peripheral surface of the reading case capable of irregular reflection, and the normal of the reading opening surface is formed to be inclined with respect to the camera optical axis. Code reader. 2. A code reader for irradiating a code with a light source installed in a reading case and reading a reflected light of the code with a camera through a light entrance diaphragm mechanism and a lens, wherein the lens and the reading surface are read. And a translucent mirror plate is provided in an inclined manner between the light source and the light source body, and the light source body is a plane luminous body that emits diffused light. . 3. The code reader according to claim 2, wherein a light absorbing plate is provided at a position opposite to the plane light emitter with respect to the translucent mirror plate.