JPH02118894A - information reading device - Google Patents

Abstract

PURPOSE:To separately install a motor for a hologram disk and a light receiving element and to improve an S/N without the influence of induction and a radiation noise by freely connecting an information signal reading part and an information signal processing part with an optical fiber. CONSTITUTION:A laser beam to exit from a semiconductor laser 11 irradiates a hologram disk 12, becomes a scanning state, and scans a bar code 24 stuck on an object 23. Reflected light beams obtained by the scanning are diffracted by the disk 12, converged by a lens 14, and guided to one edge (a) of an optical fiber 15. The bar code reflected light beam is detected by a light receiving element 17 provided for the other edge (b) of the fiber 15, converted into an electric signal, and sent to a signal processing circuit 18'. Next, the electric signal is amplified and sent to an encoding circuit and a comparator, and while the signal is encoding-processed, and the information of the bar code 24 is read in the encoding circuit, the signal is sent to a motor driving circuit as a sector signal in the comparator. This sector signal is sent through the fiber 15 to the disk 12, and the disk 12 is rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an information reading device that scans an information carrier such as a bar code with a light beam to read information on its reading surface.

2. Prior Art A conventional reading device is disclosed in Japanese Patent Publication No. 59-22992. That is, as shown in FIG. 6, the laser beam emitted from the laser beam rAL is irradiated via the lens 2 onto a sector of the hologram disk 3 which is rotated by a motor (not shown). The laser beam irradiated to this sector was scanned and attached to the object 6 through the transparent window 5 provided in the housing 4)<-
Scan the reading surface of the code label 7. By scanning the surface of this code label 7, reflected light is generated.
This reflected light is detected by a light receiving element 9 via a filter 8. By being detected by this light-receiving element 9, the information from the barcode label 7 is converted from light into an electrical signal.
This allows the barcode information to be read.

Problems to be Solved by the Invention In the conventional device as described above, a laser light source 1;
Hologram disc 3. A motor (not shown) for rotating the hologram disk 3, a light receiving element 9, etc. are housed in the same housing 4. Therefore, induced noise, radiation noise, etc. from the motor may enter the light receiving element 9, and furthermore, disturbance light may enter through the transparent window 5, resulting in S/N
There is a problem that the ratio deteriorates. Furthermore, the casing 4 itself is large and heavy, making it inconvenient to carry the device.Furthermore, since the device is being read while being carried around, there is a problem in that it cannot be used if the object itself is large or heavy.

Means for Solving the Problems In order to solve these problems, the present invention provides a laser light source and a laser light emitted from the laser light source that scans and irradiates the reading surface of an information carrier. A hologram disk that collects reflected light from the reading surface, a motor that drives the hologram disk, and one end of an optical fiber through which the light collected by the hologram disk is guided via a condenser lens are housed in the same housing. An information signal reading section housed in the information signal reading section is provided, and the other end of the optical fiber drawn out from the information signal reading section, a light receiving element disposed close to this other end side, and information detected by the light receiving element are provided. An information signal processing section is provided in which a signal processing circuit for processing a signal is housed in the same housing, and the information signal processing section and the information signal reading section are freely connected by the optical fiber. The read information is transmitted from the signal reading section to the information signal processing section.

Further, a reflection plate was attached to the surface of the hologram disk, and an optical system was provided in the information signal reading section to guide the laser beam reflected by the reflection plate to one end of the optical fiber via a condenser lens.

Therefore, by using an optical fiber, the motor that rotates the hologram disk and the light-receiving element can be separated and submerged, thereby making it possible to further downsize the information signal reading section. Since the information signal reading section can be easily carried, it becomes possible to easily read labels attached to large or heavy objects. In addition, since the light-receiving element is provided on the information signal processing side, which is not affected by motors, etc., it is not affected by induced noise or radiation noise, thereby improving the S/N ratio of the light-receiving element. Barcode data can be read stably.

In addition, since a reflector was attached to the surface of the hologram disk, the light reflected by the reflector was strong! ) The rotation of the motor can be accurately and easily controlled by guiding one light to the information signal processing section through the optical system and the optical fiber and using it as a motor control signal.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 3. The information signal reading section 10 includes a semiconductor laser 11 as a laser light source, a hologram disk 12 having a function of scanning and condensing light, and this hologram disk 12.
a motor 13 that rotates a motor 13, a condensing lens 14, and one end a of an optical fiber 15 disposed close to the condensing lens 14.
Therefore, they are housed in the same housing.

Further, the information signal processing unit 16 includes a light receiving cable 17 at the other end of the optical fiber 15 and a signal processing circuit 18 for processing the information signal detected by the light receiving element 17, and these are the same. It is housed inside the casing. The signal processing circuit 18 includes an amplifier 19, an encoding circuit 20, a comparator 21, and a motor drive circuit 22. As a result, the information signal 1BL extracting section 10 and the information signal processing section 16 are connected to each other in a free manner (herein, it means that they are separated from each other and can be used independently) by the optical fiber 15. It has become.

In such a configuration, a method for reading information on the reading surface of the barcode 24 as an information carrier affixed to the surface of the object 23 will be described. The laser beam emitted from the semiconductor laser 11 is irradiated onto the surface of the hologram disk 12, so that the laser beam is scanned, passes through a transparent window (not shown) of the housing, and is affixed to the surface of the object 23. The scanning surface of the barcode 24 that has been read is scanned. The reflected light generated by this scanning passes through the transparent window of the housing again, enters the interior, is diffracted by the hologram disk 12, and then condensed by the condensing lens 14 to the optical fiber 15.
is guided to one end a. Thereafter, the reflected light containing the barcode information is detected by the light receiving element 17 provided at the other end of the optical fiber 15 and converted into an electrical signal (hereinafter referred to as barcode information signal BS), and then sent to the signal processing circuit. Sent to 18th.

The barcode information signal BS amplified by the amplifier 19 in the signal processing circuit 18 is sent to the encoding circuit 2O and the comparator 2.
1 and 1, respectively. The encoding circuit 20 encodes the barcode information signal BS and reads the information of the barcode 24, while the comparator 21 obtains the motor drive signal MS by sending it to the motor drive circuit 22 as a sector signal C8. There is.

In this way, the information of the barcode 24 affixed to the object 23 is read. In this case, the information signal reading section 1o
and the information signal processing section 16 are connected to each other via an optical fiber 15 while being separated from each other, and since the light receiving element 17 is housed in a housing completely separate from the motor 13, the rotation of the motor 13 causes The light-receiving probe 17 no longer detects the generated induced noise or radiation noise, thereby increasing the S/N ratio and further improving the detection accuracy. Furthermore, by performing the reading operation and the analysis processing operation of the barcode information signal BS separately, the structure of the reading part can be made more compact than before, which makes it easier to carry and handle large or heavy objects. can also be easily read. Furthermore, the amount of attenuation of transmitted light within the optical fiber 15 is approximately 0.5 dB/km.

For example, when used in a campus, the barcode information signal BS can be easily read even when the information signal reading section 10 and the information signal processing section 16 are separated by about several hundred meters.

In addition, Figure 2 shows an outline of the overall configuration.
By transmitting the barcode information signal BS, which is a minute signal, using the optical fiber 15 that is separated from the power line 25 for power supply (two parallel lines, etc.), the power line 25
It is possible to prevent deterioration due to noise from

Note that the numerical aperture (N, A,) of the incident light beam that can be transmitted by the optical fiber 15 in this embodiment is the same as that of the hologram disk 1.
N, A, of the luminous flux condensed by 2. Therefore, in order to efficiently make the reflected light beams with large numbers N and A enter the optical fiber 15, a concave condensing lens 14 is used in the present invention. This allows barcode 1
24 can be efficiently transmitted to the optical fiber 15 and guided to the light receiving element 17.

Next, a modification of the above-described embodiment will be explained based on FIGS. 4 and 5. A half mirror 26 and a condensing lens 27 are included in the information signal reading section lo.

An optical system 29 including a total reflection mirror 28 is provided. Further, a total reflection mirror 31 serving as a reflection plate is attached between each sector 30 of the hologram disk 12.

In such a configuration, the laser light emitted from the semiconductor laser 11 passes through the half mirror 26 of the optical system 29 and is irradiated onto the hologram disk 12 . At this time, the laser beam that has entered the sector 3o follows the path described above and performs the normal barcode 24 reading operation.
On the other hand, the laser beam is reflected by the total reflection mirror 31 on the surface of the hologram disk 12 and then guided to the optical system 29 again. In this optical system 29, the half mirror 2
6 changes its optical path, the light is focused by a condenser lens 27, and reflected by a total reflection mirror 28. after that,
The light follows a normal path and is focused by the condenser lens 14, guided to one end a of the optical fiber 15, and further detected by the light receiving element 17 at the other end and converted into an electrical signal. This signal has a much stronger light intensity than the normal barcode information signal BS. Therefore, by using this signal with strong light intensity as the sector signal C8 and sending it to the motor drive circuit 22, the rotational state of the hologram 11 disk 12 can be detected, and thereby the rotation of the motor 13 can be accurately and easily controlled. It becomes possible to do so.

Effects of the Invention The present invention provides a laser light source, a hologram disk that scans and irradiates the reading surface of an information carrier with laser light emitted from the laser light source, and condenses reflected light from the reading surface, and the hologram disk. An information signal reading section is provided in which a driving motor and one end of an optical fiber through which light focused by the hologram disk is guided via a condensing lens are housed in the same housing, and the information signal reading section is led out from the information signal reading section. The other end of the optical fiber, a light-receiving element disposed close to the other end, and a signal processing circuit for processing the information signal detected by the light-receiving element are housed in the same housing. A signal processing section is provided, and the information signal processing section and the information signal reading section are freely connected through the optical fiber to transmit the read information from the information signal reading section side to the information signal processing section side. So I did it.

The motor that rotates the hologram disk and the light-receiving element can be provided separately, which allows the information signal reading section to be further downsized.Moreover, the information signal reading section can be easily carried, so it can be installed in a large size. This makes it possible to easily read barcode labels affixed to large objects or heavy objects.

In addition, the photodetector receives information that is not affected by motors, etc. (,7
Since it is installed on the barcode processing side, it is not affected by induced noise or radiation noise, which improves the S/N ratio of the light receiving element and enables stable reading of barcode data. It is.

In addition, a reflector is attached to the surface of the hologram disk, and an optical system is installed in the information signal reading unit to guide the laser beam reflected by the reflector to one end of the optical fiber via a condenser lens. By sequentially guiding the reflected light with high intensity to the information signal processing unit via the optical system and optical fiber, and using it as a motor control signal,
The rotation of the motor can be accurately and easily controlled.

No. processing unit, 17... Light receiving element, 18... Signal processing circuit, 24... Information carrier, 29... Optical system, 31...
·a reflector.

a... One end of the optical fiber, b... The other end of the optical fiber Applicant Rico Co., Ltd.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention, Fig. 2: A is an explanatory diagram showing the overall appearance, Fig. 3 is a block diagram of the information signal processing section, and Fig. 4 is an explanatory diagram showing the overall appearance of the invention. FIG. 5 is a plan view showing the case where one reflector is inserted between the sectors of the hologram 11 disk, and FIG. 6 is a schematic longitudinal sectional side view showing a conventional example. . 10... Information signal reading section, 11... Laser light source. [2 hologram disk, 1; 3... motor, 14...
Condensing lens, 15... Optical fiber, 16... Information transmission - Figure 3 is a diagram

Claims (1)

[Claims] 1. A laser light source, a hologram disk that scans the laser light emitted from the laser light source, irradiates it onto a reading surface of an information carrier, and collects reflected light from the reading surface, and the hologram disk. an information signal reading unit provided in the same housing with a motor that drives the hologram disk and one end of an optical fiber through which the light focused by the hologram disk is guided through a condensing lens; The other end of the optical fiber, a light-receiving element disposed close to the other end, and a signal processing circuit for processing the information signal detected by the light-receiving element are provided in the same housing. The information signal processing section and the information signal reading section are freely connected through the optical fiber to transmit read information from the information signal reading section side to the information signal processing section side. An information reading device characterized by: 2. A claim characterized in that a reflecting plate is attached to the surface of the hologram disk, and an optical system is provided in the information signal reading section to guide the laser beam reflected by the reflecting plate to one end of an optical fiber via a condensing lens. Item 1. Information reading device according to item 1.