JPH01268251A - Information reader - Google Patents

Abstract

PURPOSE:To make scanning lines easily visible by making the number of reflecting surfaces of a polygon mirror for scanning larger than that of the reflecting mirror of a polygon mirror for light reception and, at the same time, by coaxially arranging both of the polygon mirrors so that part of the reflecting surfaces of one polygon mirror can be in the same plane or parallel with part of the reflecting surfaces of the other polygon mirror. CONSTITUTION:The number of the reflecting surfaces S1, S2... of a rotating polygon mirror 10 for scanning is made larger than that of the reflecting surfaces T1-T4 of a rotating polygon mirror 15 for light reception. The polygon mirrors 10 and 15 are arranged on the same axis so that at least part of the reflecting surfaces of the polygon mirror 10 can be in the same plane or parallel with part of the reflecting surfaces of the polygon mirror 15. Since the number of the reflecting surface of the rotating polygon mirror 10 for scanning is increased, the scanning number of times of the polygon mirror in the used range is increased by the increased number of the reflecting surfaces and scanning lines can be made more easily visible. On the other hand, since the polygon mirror 10 for scanning and polygon mirror 15 for light reception are separate provided in such way, the reflecting surfaces of the polygon mirror for light reception can be increased so as to improve the reading accuracy.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an information reading device, more specifically, an information reading device that reads information on a subject by receiving light from the subject scanned by visible light 6. Regarding.

[Prior Art] Conventionally, such information reading devices are known as, for example, image scanners and barcode readers. For example, barcode readers read barcode information by scanning a barcode label with scanning light. That's what I do.

Conventional barcode readers use an infrared semiconductor laser (λ = 780 nm) as a light source. Scanning is performed using a mirror). The infrared rays reflected from the subject are received via the same rotating polygon mirror, then received by a light-receiving element such as a photodiode, converted into an electrical signal, and the information is deciphered. In order to make the entire reading device compact, such rotating polygon mirrors are usually tetrahedral mirrors, and in order to increase the amount of light received, each reflective surface is configured to have a certain area. ing.

[Problems to be Solved by the Invention] Such conventional reading devices use infrared light as a light source, so when the object, that is, the barcode, is scanned, the scanning line cannot be seen, so A visible light emitter (such as a light emitting diode) is used to aim it at the barcode through an optical system coaxial with the scanning system to form a scanning line and make it visible. Therefore, an optical system for aiming is required, which poses a problem of complicating the optical system and increasing costs.

On the other hand, semiconductor lasers that can emit visible laser light (λ = 680 nm) have recently been developed, and if information can be read by using this visible light instead of infrared light, the need for an optical system for aiming can be eliminated. can do. However, in this case, there is a problem that the number of times of scanning is reduced due to the small number of reflective surfaces of the rotating polygon mirror, making it difficult to see the scanning lines.

SUMMARY OF THE INVENTION Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a compact information reading device that scans a subject using a visible light source and allows the scanning line to be reliably seen without aiming. With the goal.

[Means for Solving the Problems] In order to solve such problems, the present invention provides a first rotating polygon that scans an object with visible light, and a second rotating polygon that receives light from the object. A mirror is provided, the number of reflective surfaces of the first polygon mirror is greater than the number of reflective surfaces of the second polygon mirror, and the reflective surface of the first polygon mirror and the reflective surface of the second polygon mirror are the same. The first and second polygon mirrors are arranged coaxially so that planes or parallel planes are formed, and the same or parallel planes of the first polygon mirror are used for reading information, and the other planes are used for reading information. A configuration was adopted in which the image was used to form scanning lines.

[Function] With this configuration, the number of reflective surfaces of the rotating polygon mirror for scanning can be increased, so the number of scans within the commonly used range increases, and the scanning line can be more easily seen. .

On the other hand, by separating the scanning polygon mirror and the light-receiving polygon mirror, the reflective surface of the light-receiving polygon mirror can be made larger and the reading accuracy can be improved. Scanning lines can be reliably formed without requiring an optical system for reading, and reading can be performed easily and with improved accuracy.

[Example] Hereinafter, the present invention will be described in detail according to an example shown in the drawings.

In the embodiment shown below, the information reading device will be described as a portable barcode reader. FIG. 1 schematically shows the external appearance of a device according to the present invention, and the reference numeral 1 denotes an information reading device, that is, a barcode reader, and the whole is compactly formed to be portable. A visible light beam emitted from a barcode reader 1 is directed toward an object, that is, a barcode label 2, and is scanned in a direction perpendicular to the barcode. The reflected light from the barcode label 2 is reflected into the barcode reader 1, converted into an electrical signal and decoded, and the information is manually input to a computer 3 or the like.

FIG. 2 shows a detailed configuration of the optical system within the barcode reader 1. As shown in FIG. The reference numeral 10 in FIG. 2 is a polygon mirror having a plurality of reflective surfaces on its circumferential surface, 12 reflective surfaces in this embodiment. 11. This barcode reader has, for example, approximately 68
Semiconductor laser diodes 1 to 12 that emit a visible light wavelength of 0 nm are provided, and the visible laser beam emitted from this light source is reflected by each reflective surface of the rotating polygon mirror 10 via a lens 13. It is directed toward the barcode label 2 to be read, and as the rotating polygon mirror rotates, the barcode label is scanned in the X direction via each reflective surface.

On the other hand, another rotating polygon mirror 1 is fixed coaxially with this rotating polygon mirror 10 and is also driven synchronously by a motor 11.
5 is provided, and this rotating polygon mirror 15 has, for example, 4
It has a reflective surface. The laser beam reflected from the barcode label 2 is received by each surface of the rotating polygon mirror 15 and reflected in the direction of the light receiving optical system. The light receiving optical system includes a bandpass filter 16 that passes only the wavelength of the semiconductor laser, a condensing lens 17, and a photodiode 18.

The reflective surfaces of each rotating polygon mirror 10.15 are arranged as shown in FIG. That is, a rotating polygon mirror 1 for scanning.
The number of reflective surfaces SL, S2, etc. of 0 is made larger than the number of reflective surfaces T1 to T4 of the rotating polygon mirror 15 for light reception. That is, in the case of this embodiment, the rotating polygon mirror 15 has four reflecting surfaces, and the reflecting surfaces of the rotating polygon mirror 10 are configured to have 12 reflecting surfaces, which is a multiple of four. In this case, the rotating polygon mirrors are arranged coaxially so that at least a portion where the reflecting surface of the rotating polygon mirror 10 and the reflecting surface of the rotating polygon mirror 15 are the same or parallel surfaces is formed. In the case of this embodiment, the reflective surface S
l, TI, and S2. T2, S3. T3, S4. T4
are arranged so that they are on the same surface.

In such a configuration, the semiconductor laser diode 1
The visible laser beam emitted from the barcode label 2 is applied to the reflective surface of the rotating polygon mirror 10 via the condensing lens 13.
A beam waist is formed near the area. Rotating polygon mirror 1
A scanning line X is formed by rotating 0 in the R direction, and the barcode label 2 is inserted into the scanning line to start reading.

By rotating the rotating polygon mirror 10, a scanning line is formed and reading is started. This situation is illustrated in FIG. Assuming that the rotating polygon mirror is in the position shown in FIG. When the direction of the rotating polygon mirror 10 rotates in the R direction, the reflecting surface S1
As the barcode label 2 rotates, the laser beam scans the barcode label 2 in the X direction. The reflected light M from the barcode label 2 is reflected by the reflective surface T1 of the rotating polygon mirror 15, passes through the filter 16, is focused by the lens 17, enters the photodiode 18, and is photoelectrically converted.

Subsequently, the rotating polygon mirror further rotates, and scanning is started by the reflecting surface 31'. Since this reflective surface Sl' is not the same surface or parallel to the reflective surface T1 of the rotating polygon mirror 15 for light reception, the reflected light obtained by scanning at that time is not used for reading, but is simply scanned. Used for forming lines.

In this embodiment, S2. T2, S3. T3, S4. T
4 are on the same surface, reading is performed when this portion is scanned, and when scanning other surfaces, no reading is performed and the result is simply the formation of scanning lines.

FIG. 4 shows the configuration of the electric circuit, and the motor 1
1 is driven by a drive circuit 20 , and the visible light laser diode 12 is driven by a drive circuit 21 .

Further, the barcode information received by the photodiode 18 is converted into an electric signal by the current-voltage conversion circuit 22, amplified by the amplifier circuit 23, converted to binary information by the binarization circuit 24, and then converted to binary information by the decoder 25. The barcode is decoded. In this case, power is supplied from the power supply 26 to each circuit.

In the circuit shown in FIG. 5, the decoder 25 or other circuits are activated in synchronization with the signal from the motor drive circuit 20 in order to electrically prohibit reading when the reflective surfaces of the polygon mirrors are not the same or parallel. Reading processing can be prohibited. This state is illustrated by the dashed line in FIG.

In the embodiments described above, the number or shape of the reflective surfaces of each polyhedron is not limited to the above example,
What is required is that the reflective surface of the rotating polygon mirror for scanning and the reflective surface of the polygon mirror for light reception be configured to have at least a portion that is the same or parallel surface, and the reading can be performed on the same or parallel surface. In other aspects, only scanning lines are formed. Therefore, the rotating polygon mirror 10 does not necessarily have to be a regular polygon, for example, S1 to S4.
Other surfaces can also be made flat.

Furthermore, it goes without saying that both rotating polygon mirrors 10 and 15 may be constructed as one body instead of separate bodies.

Furthermore, in the above-mentioned embodiment, reading of a barcode reader was explained as an example, but the invention is not limited to this.
It can also be used to read various information other than barcodes, such as image information.

[Effects of the Invention] As is clear from the above description, according to the present invention, the number of reflective surfaces of the scanning polygon mirror is greater than the number of reflective surfaces of the light receiving polygon mirror, and the number of reflective surfaces of both polygon mirrors is increased. Arrange coaxially so that the surfaces are the same or parallel,
The same or parallel surfaces of the scanning polygon mirror are used to read information, and the other surfaces are used to form scanning lines, making it easier to see the scanning lines and reducing the need for the aiming optical system. This makes the reading operation easier and improves the reading accuracy.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the external appearance of the device of the present invention, Fig. 2 is a perspective view illustrating the reading optical system in more detail, Fig. 3 is an explanatory diagram showing the relationship between scanning and reading, and Fig. 4 is an electric circuit. FIG. 2 is a block diagram showing the configuration of FIG. 2...Barcode label 10.15...Rotating polygon mirror 12...Visible light laser diode 18...Photodiode Fig. 4

Claims (1)

[Claims] 1) An information reading device that reads information about a subject by receiving light from the subject scanned by visible light, the information reading device having a plurality of reflective surfaces on the circumference and transmitting visible light through the reflective surfaces. a first rotating polygon mirror that scans the subject with visible light by rotating each reflecting surface in the direction of the subject; and a peripheral surface that is fixed coaxially with the first rotating polygon mirror and receives light from the subject. a second rotating polygon mirror having a plurality of reflective surfaces; the number of reflective surfaces of the first polygon mirror is greater than the number of reflective surfaces of the second polygon mirror; The first and second polygon mirrors are arranged coaxially so that a portion where the reflective surface of the first polygon mirror and the reflective surface of the second polygon mirror are the same plane or parallel surfaces is formed, An information reading device characterized in that one or more parallel surfaces are used for reading information, and the other surfaces are used for forming scanning lines. 2) The information reading device according to claim 1, wherein the number of reflective surfaces of the first polygon mirror is a number corresponding to an integral multiple of the number of reflective surfaces of the second polygon mirror.