JPH06195495A - Optical information reader - Google Patents

Abstract

PURPOSE:To make it possible to definitely read optical information by extremely uniformizing illuminance distribution irradiated from a light source on optical information. CONSTITUTION:Grain pattern coating is provided on the surfaces of the tip parts 12a, 12b of a lens member 1 having a lens for illumination collecting light from an illuminating light source 2 and irradiating a bar code 4 with it. Because light attenuates and reflects due to the pattern form on the surfaces of these tip parts even if the light from the illuminating light source 2 reaches these tip parts 12a, 12b by these tip parts 12a, 12b, light does not reflect on the lens for illumination and the contents of the bar code 4 can be read.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information reader.

[0002]

2. Description of the Related Art Conventionally, in a bar code reader for reading a bar code which is a kind of optical information, a light source device for irradiating light to the bar code is a light emitting LE as shown in FIG.
A light source 20 in which a plurality of D20a are arranged, a transparent lens member 21 having an illuminating lens for uniformly irradiating light from the light source 20 to the barcode, and a fixing for fixing the lens member 21 to the case 22. And the member 23. Then, the light emitted from the light source 20 is condensed by the illumination lens of the lens member 21 and emitted to the barcode.

[0003]

However, in the conventional device described above, as shown in FIG. 4, a part of the light emitted from the light emitting LED 20a is, for example, the end 21a of the lens member 21 other than the illumination lens. To the end 21a
May be reflected by the bar code and be radiated to the bar code through the illumination lens. In such a case, as shown in FIG. 6A, the reflected light from the end 21a of the lens member 21 becomes scattered light and is superimposed on the original illuminance distribution of the light source 20.

As a result, as shown in FIGS. 6B to 6D, the image information due to the reflected light from the obtained bar code is also affected by the scattered light X, and accurate image information can be obtained. There is a problem that there is no. 6 (a) is a distribution diagram showing the illuminance distribution of the light source in the conventional device, FIG. 6 (b) is a waveform diagram showing the reflected light obtained as a result of the illuminance distribution shown in FIG. 6 (a), and FIG. FIG. 6C is a partially enlarged view of FIG.
6D is a waveform diagram showing a binarized signal waveform of the signal waveform shown in FIG. 6C.

Therefore, the present invention has been made in view of the above-mentioned problems, and the optical information capable of accurately reading the optical information by making the illuminance distribution irradiated from the light source to the optical information as uniform as possible. It is intended to provide a reader.

[0006]

Therefore, the present invention is directed to a casing, a light source for irradiating the casing with the light, and an illumination optical system for condensing the light from the light source and emitting it as optical information. And a fixing member for fixing the illumination optical system to the casing, wherein the fixing member has a light beam that reaches the illumination optical system from the light source via the fixing member. The optical information reading device is characterized in that it is provided with a light attenuating member for attenuating the light intensity.

[0007]

With the above structure, the fixing member is provided with the light attenuating member for attenuating the light intensity of the light reaching the illumination optical system from the light source through the fixing member. Even if the light from the light arrives, the light intensity of the light is attenuated by the light attenuating member provided in this fixing member, and almost no noise light is incident on the illumination optical system, and the light source There is an excellent effect that the illuminance distribution irradiated from the optical information to the optical information can be made uniform as much as possible, and the optical information can be read accurately.

[0008]

The present invention will be described below based on the embodiments shown in the drawings. In this embodiment, a case where the device of the present invention is applied to a handy type bar code reader will be described.

FIG. 1 is an internal configuration diagram of a bar code reader showing an embodiment of the present invention. In FIG. 1, a bar code reader A has a case 8 formed of an electrically insulating resin, an illumination light source 2 including a plurality of red light emitting diodes, and a light from the illumination light source 2 that is condensed. A lens member 1 having an illuminating lens that emits light to a bar code 4, which is optical information, a fixing member 12 that fixes the lens member 1 to a case 8, and a one-dimensional type in which a large number of photo elements are linearly arranged. The image sensor 7 and an imaging lens 6 for forming an image of the reflected light from the barcode 4 on the image sensor 7.
And a plane reflecting mirror 5 for changing the traveling direction of the reflected light from the bar code 4 to the imaging lens 6, and a control circuit 10 for electrically processing the electric signal from the image sensor 7.

As shown in FIG. 2, the fixing member 12 for fixing the lens member 1 to the case 8 prevents light from the light source 2 from being emitted to the illumination lens through the surfaces of the end portions 12a and 12b of the lens member 1. In addition, the surface (hatched portion) is subjected to embossed coating (a method of pattern-painting the coated surface in a grain pattern). The end portions 12a, 1 of the lens member 1 are
The embossed coating applied to the surface of 2b constitutes a light attenuation member.

The image sensor 7 has a peak region of spectral sensitivity in the vicinity of the emission spectrum of the illumination light source 2, and the image sensor 7 outputs an electric signal according to the intensity of the received light.

The control circuit 10 mainly comprises a drive circuit for driving the illumination light source 2 and the image sensor 7, and a signal processing circuit for electrically processing (binarizing or the like) an electric signal output from the image sensor 7. And have.

Next, the operation of the above configuration will be described. In FIG. 1, when light is emitted from the illumination light source 2, the illumination lens of the lens member 1 collects this light and emits it to the barcode 4 printed on the label 3. Then, this light is reflected on the surface of the barcode 4.

The light reflected on the surface of the bar code 4 is changed in its traveling direction by the plane reflecting mirror 5. The reflected light whose traveling direction is changed is the condenser lens 6
Then, the image of the barcode 4 is formed on the image sensor 7 by being condensed.

Then, in the control circuit 10, the electrical signal output from the image sensor 7 is subjected to electrical processing (binarization or the like), and the electrical signal passed through the control circuit 10 is not shown via the cable 11. It is input to the host system, and the information of the barcode 4 is read by this host system.

Here, the end portions 12a, 12 of the lens member 1 are
Since the surface of b is textured, even if the light from the illumination light source 2 reaches the ends 12a and 12b, the surface of the ends 12a and 12b has a light pattern due to its pattern shape. Since the light intensity is attenuated, almost no light is reflected by the illumination lens.

As a result, as shown in FIG. 5A, the reflected light from the end portions 12a and 12b of the lens member 1 is not superimposed on the original illuminance distribution of the light source 20, and as a result, as shown in FIG.
As shown in (b) to (d), the image information obtained by the reflected light from the obtained barcode is also accurate. Note that FIG.
5A is a distribution diagram showing the illuminance distribution of the light source in the barcode reader A, FIG. 5B is a waveform diagram showing the reflected light obtained as a result of the illuminance distribution shown in FIG. 5A, and FIG. 5D is a partially enlarged view of FIG. 5B, and FIG. 5D is a waveform diagram showing a binarized signal waveform of the signal waveform shown in FIG. 5C.

As described above, in the above embodiment,
Ends 12a, 1 of a lens member 12 having an illuminating lens
Since the surface treatment of the surface 2b is performed on the surface 2b, even if the light from the illumination light source 2 reaches the ends 12a, 12b, the surface of the ends 12a, 12b has a pattern of light depending on its pattern shape. Since the intensity is attenuated and reflected, almost no noise light is incident on the illumination lens, and an accurate barcode image can be obtained.

In the above embodiment, the surface of the end portions 12a and 12b of the lens member 1 is textured, but in addition to this, the fixing member 12 for fixing the lens member 1 to the case 8 is used. The fitting portion may also be subjected to surface treatment by grain coating. By doing so, the noise component of the light incident on the illumination lens is further reduced, and the barcode image can be obtained more accurately. In this case, the wrinkle coating applied to the surface of the fitting portion of the fixing member 12 also serves as the light attenuating member.

[Brief description of drawings]

FIG. 1 is a bar code reader A showing an embodiment of the present invention.
FIG.

FIG. 2 is an enlarged view of a light source portion in the barcode reader A.

FIG. 3 is an enlarged view of a light source portion in a conventional barcode reader.

FIG. 4 is an explanatory diagram for explaining a problem of a light source portion in the conventional barcode reader.

FIG. 5 is a waveform diagram showing various signal waveforms in the conventional barcode reader.

6 is a waveform diagram showing various signal waveforms in the barcode reader A. FIG.

[Explanation of symbols]

 1 lens member 2 illumination light source 12 fixing members 12a, 12b end portions

Claims (2)

[Claims] 1. A casing, a light source for irradiating light, which is built in the casing, an illuminating optical system for condensing light from the light source and emitting it as optical information, and the illuminating optical system described above. An optical information reading device having a fixing member fixed to a casing, wherein the fixing member attenuates the light intensity of the light reaching the illumination optical system from the light source via the fixing member. An optical information reader characterized in that the optical information reader is provided. 2. The optical information reading device according to claim 1, wherein the light attenuating member is embossed on the surface of the fixing member.