JPS63231687A - Bar code detector - Google Patents

Abstract

PURPOSE:To turn on irreducible necessary light sources when lighting is necessary by providing an illumination control means which turn on all of the light sources of an illumination means only when a bar code is in the visual field of an image sensor. CONSTITUTION:The partial illumination signal 20 and full illumination signal 21 of a microcomputer 10 are made different from each other to control the illumination of LEDs. In a non-illumination state, the partial illumination signal 20 and full illumination signal 21 are held at L to turn off the light sources. In a partial illumination state, on the other hand, only the partial illumination signal 20 is held at H and then only LEDs 23 and 25 corresponding to OR circuits 28 and 29 connected to the partial illumination signal 20 illuminate. In the full illumination state, the partial illumination signal 20 and full illumination signal 21 are held at H to turn on all of the LEDs. Further, while an image sensor 6 outputs a detection signal to a digitizing means 8, the non-illumination state is entered and then the power consumption is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a barcode detection device (hereinafter referred to as a "barcode reader") used in POS, logistics, production management, etc.

BACKGROUND OF THE INVENTION Conventional barcode readers using image sensors employ a method in which the illumination means is constantly lit.

Problems to be Solved by the Invention However, since the light is always on, power consumption is large, and portable type battery-powered barcode readers have limitations on the usage time. In addition, the power consumption of the lighting means is much larger than other circuit parts (the circuit part can be reduced in power consumption by making it 0MO8, etc.), causing the problem of large power supply circuits 2 heat generation, and barcode It was difficult to make the reader smaller and lighter. Furthermore, the constant lighting system has problems with the lifespan and reliability of the projecting light source.

Means for Solving the Problems In order to solve the above problems, the present invention provides an illumination means comprising a plurality of light sources for illuminating a barcode, and an image that receives reflected light from the barcode via an optical system. 2. Digitizing the sensor and the detection signal of the image sensor.
a digitization circuit, a microcomputer that inputs the output data of the binarization circuit and performs the barcode reading process, and a part or all of the light sources of the illumination means that is intermittently turned on to perform the reading process. and a lighting control means that receives an output signal from the microcomputer and turns on all the light sources of the illumination means only while the barcode is within the field of view of the image sensor. It is.

Function: With the above-described configuration, the present invention can turn on the minimum necessary light sources when illumination is required.

Example FIG. 1 shows an embodiment of the present invention.

The barcode 3 is illuminated by the beam 2 emitted from the illumination means 1, which is composed of ten red LEDs with a wavelength λ=660 nm. The light reflected by this barcode 3 is 1oIII
II + × 40 and reflected by reflection mirror 4 with a reflectance of 90,
A one-dimensional COD image of 2048 pixels is imaged onto a sensor 6 through a condensing means 5 composed of a combination of three lenses. The light reception signal 7 outputted from the image sensor 6 is converted into a binary signal 9 via a binarization circuit 8, which is a digitization means, and is input to a microcomputer 1o, which is a reading processing means. The microcomputer 10 counts the pulse width of the binary signal 8 using an internal counter, stores it in an internal memory, and performs decoding according to the decoding algorithm of the barcode 3 based on this data.

11 is a lighting control circuit that controls lighting of the LED. Reference numeral 12 denotes a wand that covers these circuit groups, and a starting switch 13 is located in the handheld portion of the wand 12 (when a person holds it in their hand, a signal of "H" is output, and when they are not held by a person, a signal of "L" is outputted). ) is installed.

Hereinafter, the LED lighting control operation will be explained using FIGS. 2 to 4.

First, the position of the mark in Fig. 2 indicates that the power is on. Immediately after the power is turned on, all LEDs are off (lighting level C). When the start switch is turned to H at position ■ in the figure, the 10 LEDs turn on as shown by the partial lights in Figure 4.
Turn on four of them (lighting level B). and,
This partial light is turned on intermittently for 0.5 seconds and turned off for 0.5 seconds.

During this time, the microcomputer 10 counts how many black and white data strings there are during one scan of the image sensor, and if the counted value is less than 10, it turns on the intermittent lighting again. If the count is 10 or more, it is determined that the barcode is within the field of view (position marked ■ in Figure 2), and in order to input the barcode data, as shown in Figure 4.
All the LEDs are turned on at lighting level a), and when it is determined that there is no barcode within the field of view of the image sensor (position marked ■ in FIG. 2), the lights are turned off.

FIG. 6 shows an example of an LED lighting control circuit.

The cando sides of the LEDs 22, 23, 24, 25, 26, and 270 are connected to a positive power supply via a resistor, and the anode sides are connected to the output of a TTL inverter, and the LEDs light up when the input of the inverter is H.

OR circuits 2B and 29 are connected to the input of the inverter for the LEDs 23 and 25, and each OR circuit 2
8. If at least one of the inputs in 29 becomes H, the LED lights up. Therefore, by changing the levels of the partial lighting signal 20 and the full lighting signal 21 of the microcomputer 100, the lighting of the LED can be controlled.

First, in the light-off state, the partial light signal 2o and the full light signal 21 are set to L to turn off the light.

Next, in the partial lighting state, when only the partial lighting signal 2o is set to H, only the LEDs 23.26 corresponding to the OR circuits 28 and 29 connected to the partial lighting signal 20 are lit.

In addition, in the all-on state, the partial lighting signal 20° and the full lighting signal 21 are set to H to turn on all the LEDs.

Further, as shown in FIG. 3, while the image sensor is outputting a detection signal to the digitizing means, it is effective to keep the light off in order to save upstream power.

Effects of the Invention As described above, according to the present invention, it is possible to significantly reduce power consumption, extend the life of the projecting light source, and increase reliability, and the power supply circuit of the barcode reader can be made smaller.

It is lightweight and low cost, and has great industrial effects.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a barcode detection device according to an embodiment of the present invention, Figs. 2 to 4 are explanatory diagrams showing the operating state of the embodiment, and Fig. 5 is a lighting control according to the embodiment. It is a circuit diagram. 1...Lighting means, 3...Barcode,
4...Reflecting mirror, 6... Focusing means,
6... Image sensor, 8... Binarization circuit, 1o... Microcomputer, 11.
...Lighting control circuit. Name of agent: Patent attorney Toshio Nakatashi and one other person
4 School Figure 5

Claims (2)

[Claims] (1) An illumination device consisting of a plurality of light sources that illuminates the barcode, an image sensor that receives reflected light from the barcode via an optical system, and a binarization circuit that digitizes the detection signal of the image sensor. a microcomputer that inputs the output data of the binarization circuit and performs the barcode reading process; and a microcomputer that intermittently turns on some or all of the light sources of the illumination means to start the reading process. A barcode detection device comprising: a starting means; and a lighting control means that receives an output signal from the microcomputer and turns on all light sources of the illumination means only while the barcode is within the field of view of an image sensor. (2) Barcode detection according to claim 1, wherein the lighting control means is configured to turn off the light source of the illumination means while the image sensor is transmitting the detection signal to the binarization circuit. Device.