JPS62237586A - Optical symbol reader - Google Patents

Abstract

PURPOSE:To provide the titled device with semipermanent life with very high speed response by using an acoustooptical element as a high speed deflecting element. CONSTITUTION:A laser beam projected from a laser tube 1 is deflected by the acoustooptical polarizing element 2 to be controlled by an output signal 3 generated from a range finding means 16 and passed through any one of lenses 4-K in a lens group 4 setting up its focus near the position of a bar code symbol 9 of an article carried on a conveyer 15. The laser beam projected from the lens 4-K is converted at its direction by direction converting mirrors 5, 6, and deflected by a polygon mirror 7 through a perforated mirror 16, and converted at its direction by a fixed mirror 8 to scan the bar code symbol 9. The reflected light from the symbol 9 is run in the reverse course, converted at its direction by the mirror 16, converged by a condenser lens 10, and transduced into an electric signal by a photoelectric transducer 12 through a filter 11 and the electric signal is amplified by an amplifier 13.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical symbol reading device for reading barcode symbols affixed or printed on articles, and in particular an automatic focusing system that has a fast response and a semi-permanent lifespan. This invention relates to an optical symbol reading device adopted in

[Prior Art] As an automatic focus adjustment method of a conventional optical symbol reading device, the beam focus 21! is mechanically adjusted. There is a method of moving the JwJ lens. This method is also used in autofocus cameras and the like.

FIG. 2(a) is a schematic configuration diagram of a conventional optical reading device, and FIG. 2(b) is an external perspective view thereof.

In the figure, 37 is the main body of the device, and 39 is a distance measuring means.

The main body 37 of the device includes a laser tube 21. Auto focus fIji [
Dan? ? , direction conversion mirror 25.26, polygon mirror 2
7, fixed mirror 28.1/lens 30° filter 31, photoelectric conversion cable-f-32, video amplifier 33, decoder 34,
It is composed of a perforated mirror 36.

Here, the automatic focusing fmF□ stage 22 is configured to mechanically change the position of the lens to adjust the focus, and the distance measuring "stage 3"
The output value from 9 is controlled by 23, and a focus is set near the position of barcode symbol 29 of article 38 conveyed by compare 35. The laser beam from the laser tube 1 is transmitted through an autofocus m-node r single stage 22, direction conversion mirrors 25, 26, . The 17-C direction is converted through a polygon mirror 27 or the like, and the barcode symbol 29 is scanned. Then, the reflected light from the barcode symbol 29 is 4
4: Converted to a signal and recognized by the decoder 34.

[Problems to be Solved] In the conventional optical symbol reading device described above, the first stage of automatic focus adjustment has a structure in which the focus is adjusted by mechanically moving the lens, so the reading response speed is 8. , and also had shortcomings such as short lifespan and lack of reliability.

[Solving the Problems Step F] The optical reader of the present invention solves the above-mentioned conventional problems. The reading device includes a scanning light-receiving optical system that scans a barcode symbol with a scanning beam and receives reflected light; an amplifier that converts a signal into an electrical signal and amplifies it; a recognition section that receives and decodes the output of the video amplifier; a distance measurement section that measures the distance to the barcode symbol; and an output signal of the distance measurement section. In an optical symbol reading device, the beam focus adjusting section is configured to focus the beam at a predetermined focal position with a blind optical modulator, respectively. It consists of multiple lenses installed in a similar manner.

[Example] Hereinafter, ruled lines will be explained with reference to drawings showing a preferred example of the unreleased item 1.

FIG. 1(a) is an optical symbol 1 according to an embodiment of the unreleased Yu1.
A schematic configuration diagram of the reading device, FIG. 1(b) is a perspective view of its appearance. The optical symbol reading device of this embodiment is shown in FIG.
) The device consists of a main body 17 and a distance measuring means 16 shown in FIG. The device main body 17 includes a laser tube 1. Acousto-optic deflection element J-2
, a lens group 4. consisting of a plurality of lenses 4-1 to 4-n. Direction changing mirror 5.6. Polygon Mi)-7, fixed mirror 8
, condensing lens 10, filter 11. photoelectric exchange element 12,
Video amplifier 13. Decoding unit 14. In this embodiment, which is composed of a five-hole mirror 16, instead of an automatic focusing means that mechanically moves the lens to adjust the focus as in the past, it focuses on a predetermined focal position. A lens group 4 consisting of a plurality of lenses 4-1 to 4-n is provided, and any lens 1- of this lens group 4 is
k is selected by the acousto-optic deflection element 7-2 to adjust the focus.

The laser light emitted from the laser tube 1 enters the ff 2F optical deflection element f-2, which is controlled by the output signal 3 from the distance measuring means 16, and is deflected by the conveyor 15. h is conveyed 6 goods 1
Any lens 4-k in lens group 4 that sets the focus on barcode symbol 9'ell +J-M of 8
pass through. The direction of the laser beam exiting the lens 4-k is changed by direction conversion mirrors 5 and 6.

It passes through a perforated mirror 16, is deflected by a polygon mirror 7, and is changed in direction by a fixed mirror 8 to scan a barcode symbol 9.

The reflected light from the barcode symbol 9 follows a reverse path, is direction-changed by a perforated mirror 16, is condensed by a condenser lens, passes through a filter 11, and is converted into a light beam by a mirror 16: 7-1
2, it is converted into an electrical signal, and the video amplification 'A1
3 and is amplified and shaped and recognized by the decoding unit 14.

[Effects of the Invention] As explained above, the present invention uses an acousto-optic element as a high-speed deflection element, and in combination with a lens group each set to focus on a predetermined focal position, it is possible to achieve an electric T. Since the focus position can be switched, it is possible to realize an automatic focus adjustment system with ultra-high-speed response and a semi-permanent lifespan.

Note that similar effects can be obtained by using an electro-optic element instead of the acousto-optic element.

[Brief explanation of drawings]

FIG. 1(a) is a schematic configuration diagram of an optical symbol reading device according to an embodiment of the present invention, and FIG. 1(b) is an external side view of the optical symbol reading bag shown in FIG. 1(a). FIG. 2(a) is a schematic configuration diagram of a conventional optical symbol reading device. FIG. 2(b) is a perspective view of the external appearance. 1: Laser tube 2: Acousto-optic deflection element 4: Lens group 7: Polygon mirror 9: Barcode symbol 12: Photoelectric conversion element 14: Decoding section 16: Distance measuring section

Claims (2)

[Claims] (1) A scanning light-receiving optical system that scans a barcode symbol with a scanning beam and receives the reflected light, a video amplifier that converts the received light signal into an electrical signal and amplifies it, and a recognition system that receives and decodes the output of the video amplifier. an optical symbol reading device comprising: a distance measuring section that measures a distance to a barcode symbol; and a beam focus adjustment section that adjusts a focal position of a scanning beam using an output signal of the distance measuring section; What is claimed is: 1. An optical symbol reading device, characterized in that the focus adjustment section is composed of an acousto-optic modulation element and a plurality of lenses installed so as to each focus on a predetermined focal position. (2) The beam focus adjusting section is comprised of an electro-optic modulation element and a plurality of lenses each installed to focus at a predetermined focal position.
Optical symbol reading device as described in paragraph.