JPH08315062A - Two-dimensional symbol reader - Google Patents

Abstract

PURPOSE: To prevent the halation of light and to accurately read out a two-dimensional (2D) symbol by preventing a printing medium from being irregularly irradiated with illuminating light. CONSTITUTION: This 2D symbol reader is provided with a diffusion plate 15 inserted into a direct optical path from a light source unit 3 to an aperture 13 and an irregular reflection face 16 formed on the inner side face of a reading cover 12 to irregularly reflect illuminating light deviated from the direct optical path from the unit 3 to the aperture 13 and the center axis of illuminating light from the unit 3 is deviated from the optical path to the plate 15 so as to arrive at the face 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional symbol reading device for reading a two-dimensional symbol on a print medium.

[0002]

2. Description of the Related Art As a handy type two-dimensional symbol reading apparatus, as shown in FIG. 4, a reading port 101 is set so that a two-dimensional symbol on a print medium is accommodated, and a trigger switch (not shown) is used. A two-dimensional symbol reading operation is started by turning ON the.

Inside the reading port 101, a light source 102 for illuminating the two-dimensional symbol with illumination light is arranged. Reflected light from the two-dimensional symbol is reflected to the inside of the apparatus by a folding mirror 103. An image is formed at the position of the area sensor 105 via the optical mechanism 104 composed of a lens and the like. This area sensor 105 is, for example, a CCD
It is configured by arranging (charge coupled device) elements in a matrix, and outputs an electric signal according to the amount of received light.

In such a conventional two-dimensional symbol reading apparatus, the illumination light from the light source 102 is directly applied to the two-dimensional symbol, and the reflected light is imaged at the position of the area sensor 105.

[0005]

By the way, the light source 102
Generally, the illumination light from the light source (for example, the light emitting diode) 102 has unevenness, and the intensity is strong at the central portion of the irradiation. This central part may be strongly reflected. In particular, when a print medium that is easily reflected is used, or even in a portion printed in black, the reflectance may be abnormally higher than the reflectance of the blank space of a normal non-printed portion.

For example, as shown in FIG. 5, when the central axis of the illumination light from the light source 102 is indicated by a broken line, the two-dimensional symbol 1
The position where the broken line on 06 hits is a strong reflection position. Further, also in the two-dimensional symbol 106 of the cylindrical print medium as shown in FIG. 6, similarly, there is a strong reflection portion due to the relationship between the incident angle and the reflection angle.

In such a case, which is called light halation, an originally black part is read as a white part, and an image in which a part of the two-dimensional symbol is missing is read, and the two-dimensional symbol is accurately read. There was a problem that I could not do it.

Therefore, according to the present invention, it is possible to prevent uneven irradiation of illumination light on the print medium to prevent light halation, and to accurately read a two-dimensional symbol.
An object is to provide a dimensional symbol reader.

[0009]

The invention according to claim 1 is
In a two-dimensional symbol reading device for reading a two-dimensional symbol on a print medium, a light source for irradiating illumination light and a diffusing member for diffusing the illumination light on a straight optical path from the light source to the two-dimensional symbol on the print medium are provided. It is a thing.

According to a second aspect of the invention, in the first aspect of the invention, an irregular reflection member is provided for irregularly reflecting the illumination light from the light source to the two-dimensional symbol on the print medium.

In the invention according to claim 3, in the invention according to claim 2, the light source is arranged such that the irradiation central axis of the illumination light hits the diffuse reflection member while avoiding the diffusion member.

[0012]

According to the first aspect of the invention, the direct illumination light from the light source to the two-dimensional symbol is diffused by the diffusing member provided on the straight optical path from the light source to the two-dimensional symbol on the print medium. Therefore, the reflected light from the two-dimensional symbol has no convergence and no deviation, and the uniformity is high.

In the invention corresponding to claim 2, claim 1
In addition to the operation of the invention described above, the irregular reflection plate diffuses the illumination light from the light source to the two-dimensional symbol, so that the illumination light that illuminates the two-dimensional symbol is reinforced with high uniformity.

In the invention corresponding to claim 3, claim 2
In addition to the action of the invention described, the irradiation center axis of the illumination light from the light source is arranged so as to hit the diffuse reflection member while avoiding the diffusion member, and the irradiation center portion with the highest light intensity of the illumination light is diffused by the diffuse reflection member. Since the light is diffusely reflected, the uniformity of the illumination light transmitted through the diffusing member can be guaranteed, and the intensity of the illumination light that illuminates the two-dimensional symbol becomes high.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a schematic internal configuration of a handy type two-dimensional symbol reader 1 to which the present invention is applied.

The two-dimensional symbol reader 1 includes a light source unit 3 for irradiating a two-dimensional code with light, a reflecting mirror 4, a lens mechanism 5, a CCD (ch
an image sensor 6 formed by arranging a large coupled device) in a matrix, a circuit board 7 composed of a signal processing circuit (not shown), a binarization circuit, an identification circuit, a decoding circuit, a communication circuit, etc. The light source 8 is provided.

This circuit board 7 is further electrically connected to a trigger switch (not shown) provided on the frame 2 and a display lamp 9 composed of an LED.

The circuit board 7 is electrically connected to a connection cable 10 connected to an external data processing unit (not shown). The connection cable 10 is fixed to the frame 2 via a protective member 11.

An opening is formed on the opposite side of the frame 2 to which the connection cable 10 is fixed, and a cylindrical reading cover 12 is integrally removably provided on the frame 2. . However, this reading cover 1
The item 2 is usually not attached and removed frequently, and is attached and detached only for inspection and repair, for example, and is fitted and fixed so as not to come off easily during normal use. The opening 13 on the opposite side of the fitting portion of the reading cover 12 to the frame 2 serves as a reading port.

The inside of the reading cover 12 has the opening 1
3 is closed by a dustproof cover 14 formed of a transparent plastic material or the like which prevents the pride and moisture from entering the circuit board 7 inside.
4 is provided with a diffuser plate 15 as a diffusing member for diffusing the direct light from the light source unit 3 to the opening 13, and a diffused reflecting member having a white surface treatment is provided on an inner side surface of the reading cover 12. The irregular reflection surface 16 is formed. The diffusing plate 15 may be a transparent member that has been subjected to a surface treatment (coating) to make the surface of the transparent member have a minute unevenness, or a sticker having a minute unevenness formed on the surface thereof may be attached to the reading cover 12. Then, a part of the reading cover 12 may be used as a diffusion plate.

FIG. 2 is a sectional view showing the reading cover 12 portion of the two-dimensional symbol reading apparatus 1.

The central axis of the irradiation light emitted from the light source unit 3 deviates from the optical path to the diffusion plate 15 and reaches the irregular reflection surface 16 directly, as shown by the alternate long and short dash line in the figure. ing.

In the present embodiment having such a structure, as shown in FIG. 3, the diffusion plate 15 is inserted so as to cover the entire surface of the direct optical path from the light source unit 3 to the opening 13, and the light source is provided. The direct illumination light from the unit 3 to the opening 13 is
All are transmitted through this diffusion plate 15 and diffused.

Further, all the illumination light deviated from the optical path from the light source unit 3 to the opening 13 is irradiated to the irregular reflection surface 16 formed on the inner side surface of the reading cover 12 and irregularly reflected,
The opening 13 is irradiated.

Further, the central axis of the illumination light from the light source unit 3 deviates from the optical path to the diffusion plate 15, and the diffuse reflection surface 1 is directly reflected.
Since it reaches 6, the strongest illumination light is diffusely reflected by the irregular reflection surface 16.

Therefore, the two-dimensional symbol of the print medium set in the opening 13 is made to overlap the illumination light transmitted through the diffusion plate 15 and diffused with the illumination light diffusely reflected by the irregular reflection surface 16. The two-dimensional symbol is not irradiated with the illumination light directly emitted from the light source unit 3.

The light from the auxiliary light source 8 is spot light for indicating the center of the reading field of the two-dimensional symbol reading device 1 on the print medium close to the opening 13 and is turned off during image reading.

As described above, according to this embodiment, the diffusion plate 1 inserted in the direct optical path from the light source unit 3 to the opening 13 is provided.
5 and the irregular reflection surface 16 formed on the inner side surface of the reading cover 12 that irregularly reflects the illumination light deviated from the direct light path from the light source unit 3 to the opening 13, and the central axis of the illumination light from the light source unit 3 is provided. By arriving at the irregular reflection surface 16 by removing it from the optical path to the diffusion plate 15, it is possible to prevent uneven irradiation of the illumination light on the print medium and prevent halation of light. As a result, the two-dimensional symbol can be read accurately.

[0029]

As described above in detail, according to the present invention,
It is possible to provide a two-dimensional symbol reading device capable of preventing uneven irradiation of illumination light on a print medium to prevent light halation and reading a two-dimensional symbol accurately.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic internal structure of a two-dimensional symbol reading device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a reading cover portion of the two-dimensional symbol reading device according to the embodiment.

FIG. 3 is a diagram showing an optical path from a light source unit of the two-dimensional symbol reading apparatus of the embodiment.

FIG. 4 is a diagram showing a conventional two-dimensional symbol reading device.

FIG. 5 is a diagram showing an example of an optical path from a light source unit of a conventional two-dimensional symbol reading device.

FIG. 6 is a diagram showing another example of an optical path from a light source unit of a conventional two-dimensional symbol reading device.

[Explanation of symbols]

 3 ... Light source unit, 12 ... Reading cover, 15 ... Diffusion plate, 16 ... Diffuse reflection surface.

Claims (3)

[Claims] 1. A method for reading a two-dimensional symbol on a print medium 2
A two-dimensional symbol reading apparatus, wherein a two-dimensional symbol reader comprises a light source for irradiating illumination light and a diffusing member for diffusing the illumination light on a straight optical path from the light source to the two-dimensional symbol on the print medium. Reader. 2. The two-dimensional symbol reading device according to claim 1, further comprising: a diffuse reflection member that diffuses illumination light from the light source into a two-dimensional symbol on the print medium. apparatus. 3. The two-dimensional image reading apparatus according to claim 2, wherein the light source is arranged so that a central axis of irradiation of the illumination light hits the irregular reflection member while avoiding the diffusion member. Dimensional symbol reader.