JP2779846B2 - Barcode reader - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a barcode reader that irradiates a barcode label with light, receives reflected light from the barcode label, and reads barcode information.

(Conventional technology) A bar code reader that reads bar code information includes a light emitting unit that irradiates light onto the bar code, a light receiving unit that receives light reflected from the bar code, and a signal that converts a light receiving signal into an electric signal. It comprises a conversion circuit and a microprocessor which receives the output of the conversion unit and decodes barcode information. FIG. 6 shows an example of the configuration. Reference numeral 1 denotes a light projecting unit which includes a light projecting light source 11 and a light projecting light source driving circuit 12. 2 is a bar code label, 3 is a light receiving unit, a light receiving lens 31 for forming an image of the bar code label 2 on the image sensor 32, and an image sensor 32 for electrically converting the image of the bar code label 2 into a light receiving signal. Consists of Reference numeral 4 denotes a signal conversion circuit, which includes a variable gain amplifier 41 for amplifying the signal output of the image sensor 32 to a predetermined amplitude in accordance with a command from the microprocessor 5, and a filter 42 for removing a high frequency noise component of the variable gain amplifier output.
And a floating binarization circuit 43 for converting the filter output into a binary level signal corresponding to the bar width of the bar code label 2. Reference numeral 5 denotes a microprocessor which receives the output of the floating binarization circuit from the input port 51 and decodes the barcode information of the barcode label. 53 is the image sensor 32
Output port for outputting a clock for driving
Is a timing generation circuit that generates a pulse for driving the image sensor 32 by a clock.

(Problem to be Solved by the Invention) In the configuration example shown in FIG.
ht Emitting Diodes, semiconductor laser diodes, and the like. However, the brightness of these light-emitting elements drops to less than half of the initial brightness in thousands to tens of thousands of hours. Therefore, the conventional bar code reader has a problem in that the bar code reading deteriorates due to a decrease in the light receiving unit signal level due to a decrease in the light emitting unit luminance during long use.

(Means for Solving the Problems) In order to solve these problems, a first aspect of the present invention is to provide a light emitting unit that irradiates light onto a bar code, a light receiving unit that receives light reflected from the bar code, A signal conversion circuit for converting the output of the light receiving unit into an electric signal corresponding to the bar width of the bar code;
A light amount detection circuit that detects the amount of light received by the light receiving unit from the light receiving unit output, a microprocessor that inputs the output of the signal conversion circuit and the output of the light amount detection circuit and decodes barcode information, and displays the data according to a command from the microprocessor. And a bar code label for adjustment with a known light reflectance.

A second aspect of the present invention is a light emitting unit including a light emitting source for emitting light onto a bar code and a light amount adjusting unit for adjusting the amount of light emitted from the light emitting source in response to an instruction from the outside, A light receiving unit for receiving the reflected light, a signal conversion circuit for converting the output of the light receiving unit into an electric signal corresponding to the bar width of the bar code, and a light amount detection circuit for detecting the light receiving amount of the light receiving unit from the output of the light receiving unit A microprocessor that inputs the output of the signal conversion circuit and the output of the light amount detection circuit, decodes bar code information and controls the irradiation light amount of the light projecting unit, and display means for performing display according to instructions from the microprocessor. And an adjustment barcode label having a known light reflectance.

(Operation) In the first configuration of the present invention, first, it is determined whether or not the read barcode is of an adjustment barcode label, and if not, the read data is transmitted. I do. Conversely, when the adjustment barcode label is read based on the reflected light from the adjustment barcode label having a predetermined reflectance, the amount of light received at the time of reading is detected, and the amount of light emitted from the projection light source is detected. Determine the decrease. When the irradiation light quantity is decreasing, the operator is warned of the decrease in the light quantity via the display means, so that it is possible to easily detect the decrease in the luminance of the projection light source.

Further, in the second configuration of the present invention, similarly to the first configuration, first, it is determined whether or not the read barcode is of the barcode label for adjustment. Transmits the read data. vice versa,
If it is determined that the label is for an adjustment barcode label, and if the irradiation light amount has decreased, the irradiation light amount of the light emitting unit is increased until the light reception amount reaches a predetermined light reception amount in accordance with a command from the microprocessor. If the amount of received light does not reach the predetermined amount of light even when the amount of light emitted from the light emitting unit is maximized, the operator is warned via the display means of a decrease in the amount of light. Therefore, in the present invention, while improving the reduction in reading performance due to the reduction in luminance,
This makes it possible to easily detect a decrease in the brightness of the light projecting light source.

Further, according to the first and second configurations of the present invention, the adjustment barcode label is read in the same state as when reading the actual barcode label. Deterioration of the amount of light finally input to the light receiving unit is determined by dirt on the optical path inside the code reader, for example, dirt or scratches on the light receiving lens surface.
Deterioration of the function of the entire bar code reader can be determined.

(Example) Hereinafter, an Example is described in detail with reference to drawings. First
FIG. 1 shows a first embodiment of the present invention, wherein 1 is a light projecting unit, which is composed of a light projecting light source 11 composed of an LED and a light projecting light source driving circuit 12 for causing the LED to emit light. Reference numeral 2 denotes an adjustment barcode label, and reference numeral 3 denotes a light receiving unit. The light receiving lens 31 forms an image of the barcode label 2 on the image sensor 32 and the image sensor 32 converts an image of the barcode label into an electric light reception signal. It is configured. Reference numeral 4 denotes a signal conversion circuit, which is a variable gain amplifier 41 that amplifies the signal output of the image sensor 32 to a predetermined amplitude in accordance with a command from the microprocessor 5, and a filter that removes high frequency noise components from the output of the variable gain amplifier 41.
And a floating binarization circuit 43 for converting the filter output into a binary level signal corresponding to the bar width of the bar code label. Reference numeral 5 denotes a microprocessor which receives the output of the floating binarization circuit 43 from the input port 51 and decodes the bar code information of the bar code label. Reference numeral 6 denotes a timing generation circuit for generating an operation clock for the image sensor 32 and the received light amount detection circuit 8 from a clock output from the microprocessor output port 53. Reference numeral 7 denotes a command from the output port 55 of the microprocessor 5 to the operator. A light receiving light detecting circuit 8 for integrating the light receiving light output for one scan of the image sensor with the clock of the timing generating circuit 6; And a A / D conversion circuit 83 that converts the output of the hold circuit 82 into a digital signal. The output of the A / D conversion circuit 83 is input to the microprocessor 5 from the input port 54.

FIG. 3 shows a specific circuit example of the received light amount detection circuit 8. An operational amplifier is used for the AMPs 1 and 2, and an 8-bit A / D converter is used for the A / D conversion circuit 83.

FIG. 2 shows a processing flow of the microprocessor 5. Hereinafter, specific processing of the barcode reader of the present embodiment will be described with reference to FIG.

After the start of the reading process, the output of the output port 52 sets the gain of the variable gain amplifier 41 (process a). Next, the bar width data of the bar code is fetched from the input port 51 (process A). The fetched data is decoded (process c), and in the case of a decoding error, the process returns to process A again, and the same process is repeated with the gain of the variable gain amplifier 41 changed. If the decoding is OK, it is determined whether or not the read code is an adjustment barcode label (processing d and e). If the barcode label is not an adjustment barcode label, the reading data is transmitted to complete the reading process (process F). In the case of an adjustment bar code label, the bar code data is fetched again (processing key), the output of the received light amount detection circuit 8 at the time of bar code fetching is input from the input port 54, and the received light amount is detected (processing).
As a result of the processing, if the amount of received light is larger than a predetermined value,
Alarm circuit 7 for receiving light quantity OK alarm from output port 55
Is output through (processing key, co). If the received light amount is smaller than the predetermined value, the received light amount error alarm is output from the output port 55 via the alarm circuit 7, and the processing is terminated (processing step S).

As described above, in the bar code reader of the present embodiment, the operator can read the adjustment bar code label, thereby easily detecting a decrease in the brightness of the light emitting light source 11.

FIG. 4 shows a second embodiment of the present invention, wherein 1 is a light projecting unit, which is a light projecting light source (LED) 11, a light projecting light source driving circuit 12 for emitting light from the LED, and a microprocessor 5 The light amount adjusting circuit 13 controls the irradiation light amount of the light projecting light source 11 by changing the output of the light projecting light source driving circuit 12 in accordance with the output of the output port 56 in accordance with the instruction. Reference numeral 2 denotes a bar code label for adjustment, and the following 3 to 8 are the same as those in the first embodiment shown in FIG.

FIG. 5 shows a processing flow of the microprocessor 5 in the present embodiment, and specific processing of the barcode reader of the present embodiment will be described below with reference to FIG.

After the start of the reading process, the output of the output port 52 sets the gain of the variable gain amplifier 41 (process a). Next, the bar width data of the bar code is fetched from the input port 51 (process A). The fetched data is decoded (process C), and in the case of a decoding error, the process returns to process A, and the same process is repeated with the gain of the variable gain amplifier 41 changed. If the decoding is OK, it is determined whether or not the read code is an adjustment barcode label (processing d and e). If the barcode label is not an adjustment barcode label, read data is transmitted, and the reading process is completed (processing f). In the case of an adjustment bar code label, the bar code data is fetched again (processing key), the output of the received light amount detection circuit 8 at the time of bar code fetching is input from the input port 54, and the received light amount is detected (processing). As a result of the processing, if the received light amount is larger than the predetermined value, a received light amount OK alarm is output from the output port 55 via the alarm circuit 7 (processing part (k)). If the received light amount is smaller than the predetermined value, it is checked whether or not the irradiation light amount of the light projecting light source 11 at the time of reading the adjustment barcode label is the maximum (process S). If the irradiation light amount is the maximum, the received light amount error alarm is output from the output port 55 via the alarm circuit 7 and the processing is terminated (processing step). When the irradiation light amount is not the maximum, the light amount adjustment circuit 13 is output from the output port 56.
To increase the irradiation light amount of the light projecting light source 11 via the light projecting light source driving circuit 12, and thereafter perform the processing keys, c, c, c, c, and c until the received light amount reaches a predetermined light amount (processing co). Alternatively, the process is repeated until the irradiation light amount becomes the maximum and the received light amount error occurs (processing step).

As described above, in the barcode reader of the present embodiment, the operator adjusts the irradiation light amount of the light emitting light source 11 by reading the adjustment barcode label, thereby improving the deterioration of the reading performance due to the decrease in luminance. This makes it possible to easily detect a decrease in luminance.

(Effect of the Invention) As described above, the barcode reader of the present invention automatically performs the normal processing when the read barcode is not from the adjustment barcode label by the same operation as the normal barcode reading. Can be performed, and even when reading from the adjustment bar code label, the judgment does not confuse with the normal reading process and cause erroneous recognition. It can be easily detected.

(2) It is possible to improve the deterioration of the reading performance due to the lowering of the brightness of the light emitting source of the light emitting section.

(3) It is possible to determine not only a decrease in the brightness of the light projection light source but also a decrease in the function of the entire barcode reader due to dirt on the optical path.

It has excellent effects.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention, and FIG.
FIG. 3 is a specific circuit diagram of a light-receiving amount detection circuit, FIG. 4 is a block diagram of a second embodiment of the present invention, FIG. 5 is a flowchart of the same embodiment, FIG. FIG. 6 is a configuration diagram of a conventional example. DESCRIPTION OF SYMBOLS 1 ... Light transmission part, 2 ... Bar code label, 3 ... Light receiving part, 4 ... Signal conversion circuit, 5 ... Microprocessor, 6 ... Timing generation circuit, 7 ... Alarm circuit, 8 ... Light reception Light amount detection circuit, 13 ... Light amount adjustment circuit.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-19094 (JP, A) JP-A-60-163180 (JP, A) JP-A-3-14190 (JP, A) JP-A-2- 113121 (JP, A) Japanese Utility Model Showa 64-57551 (JP, U) Japanese Utility Model Showa 62-93266 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G06K 7/00

Claims (2)

(57) [Claims] 1. A light projecting unit for irradiating light onto a bar code, a light receiving unit for receiving reflected light from the bar code, and converting an output of the light receiving unit into an electric signal corresponding to the bar width of the bar code. A signal converting circuit, a light amount detecting circuit for detecting a light receiving amount of the light receiving unit from an output of the light receiving unit, and an output of the signal converting circuit and an output of the light amount detecting circuit, and decode the barcode information. A microprocessor comprising: a microprocessor; a reader unit having display means for performing display according to instructions from the microprocessor; and an adjustment barcode label having a known light reflectance, wherein the read barcode is the adjustment barcode label. If the read bar code is not the adjustment bar code label, the read data is transmitted, and the reader unit controls the adjustment bar code. When reading the adjustment bar code label based on the reflected light from the label, if the light amount detection value of the light amount detection circuit connected to the light receiving section is smaller than a predetermined value, display is performed by the display means. A bar code reader, characterized in that: 2. A light projecting unit comprising: a light projecting light source for irradiating light onto a bar code; and a light amount adjusting means for adjusting an irradiation light amount of the light projecting light source according to an external command. A light receiving unit for receiving light, a signal conversion circuit for converting an output of the light receiving unit into an electric signal corresponding to a bar width of the bar code, a light amount detection circuit for detecting a light receiving amount of the light receiving unit from an output of the light receiving unit, A microprocessor that receives the output of the signal conversion circuit and the output of the light quantity detection circuit, decodes the bar code information, and controls the irradiation light quantity of the light projecting unit; A reading unit comprising a reader unit having a means and a barcode label for adjustment whose light reflectance is known, and determining whether or not the read barcode is the barcode label for adjustment. If the read bar code is not the adjustment bar code label, the read data is transmitted, and the reader unit reads the adjustment bar code label based on the reflected light from the adjustment bar code label. Controlling the irradiation light amount of the light projecting unit so that the light amount detection value of the light amount detection circuit connected to the light receiving unit falls within a predetermined range, and when the control cannot be performed, the display is performed by the display means. A bar code reader, characterized in that: