JPS60103491A - Optical reader - Google Patents

Abstract

PURPOSE:To know previously the deterioration of a light source by using a means which controls the light emission of the light source in response to the difference between the output signal of a photoelectric transducer and a fixed level and delivering an alarm when said controlled variable of the light emission exceeds a fixed level. CONSTITUTION:The quantity of light emission of lamps 2 and 3 are controlled to always keep the output of a photoelectric transducer 5 at a fixed level by a deviation amplifying circuit 7 and a deviation detecting circuit 6 which obtains the difference between the output signal of the transducer 5 and the target value alpha. While the manipulated variable beta given from the circuit 7 is compared with a fixed value gamma through a comparator 11. If the positive correlation is obtained between the light quantity and the variable beta, the variable beta is smaller than the value gamma within an application range for control of light quantity. Then the variable beta increases gradually for optimum control as a light source is deteriorated and the light quantity becomes short. Finally the variable beta becomes larger than the value gamma. Thus an alarm device 13 like a buzzer, etc. is actuated by an alarm actuating circuit 12.

Description

[Detailed Description of the Invention] B) Technical field This invention is applicable to handwriting, barcode processing, and barcode processing.
This relates to an optical reading device that optically reads characters, etc., and in particular, an optical reading device C that is equipped with an alarm means that detects and issues an alarm when its light source has deteriorated. .

(b) Products (11
2. Description of the Related Art Hand scanners that optically read barcodes or characters written on bills, etc. have come into widespread use.

Hands like this 4.1'7'C1 lamp,
A light source such as LEI) is used. However, these light sources are consumables, and the amount of light decreases as the usage time increases, and even if the light is reflected from the same object, the amount of light m received by the photoelectric conversion element decreases, and its output decreases.

A decrease in the output of the photoelectric conversion element will result in malfunction or an unreadable state! It is desirable to take some measures.

If the output fluctuations of the photoelectric conversion element (including changes in the amount of light due to qualitative changes in the target paper, changes in the output of the photoelectric conversion element, etc.) are not so noticeable, the output change 1PIJφ is fed back to the light source drive circuit. In particular, devices for adjusting the output to an optimal value have already been proposed.

Figure 1 shows the above-mentioned conventional device.
A pair of lamps 2.3 as a light source are provided in the case 1 of the pump, and a circuit 6.7 is built in as a means for adjusting the amount of light emitted from the lamps 2.3 by the output of a lens 4 and a photoelectric conversion element 5. are doing.

Is that means light? 11) There is a means for increasing or decreasing the emitted light (6) of the lamp 2.3 in order to keep the output of the light emitting device 5 constant at all times.
It consists of a deviation detection circuit 6 that calculates the difference between d and &i difference amplification circuit 7.
When the applied voltage or the current flowing through the lamps 2 and 3 is smaller than Llow IIr+d, the voltage or current is increased, and when the voltage or current is high, it is decreased. Ru.

Further, the output signal of the photoelectric conversion element 5 is connected via a cable 8 to a terminal t'A+ 9 for recognition of human characters, notes, etc.

It should be noted that the figure shows the object of reading old price tags, etc.

However, in the above-mentioned device, if the light source deteriorates further, a sufficient amount of light cannot be obtained even with feedback, making it impossible to optimize the output. This is a limitation of the device described above.

(c) Purpose of the Invention This invention was made in order to solve the problems of conventional optical reading devices, such as the high cost. It is an object of the present invention to provide an optical reader having means for issuing a warning.

That is, the present invention transmits the output signal of a photoelectric conversion element of an optical reading device such as a hand scan One stage of f is provided, and the control value of the light emission amount control means is compared with a constant value (independent of the constant value), and when the control value of the control unit exceeds the constant value, the lamp,
The present invention is characterized by providing a means for warning that the capacity of the C light source is decreasing by means of a warning means such as a buzzer.

(d) Examples The details of this invention will be explained below with reference to FIG.

This figure is a3 and C figure 1 is the same! l What is the part that says rli? 411 (13-none cargo number is fq and 1-state light is omitted.

In the case of the present invention, the manipulated variable β is taken out from the difference amplifier circuit 7 and compared to a constant value γ in the comparison circuit 11. This γ defines one limit of the operation ω. If the amount of light and the amount of operation β have a positive (b) correlation, β is smaller (larger) than γ within the applicable range of the light fQ iJJ adjustment.

However, as the light source deteriorates and the light weight becomes insufficient, the operation Mβ must be gradually increased (decreased) for optimal adjustment. Become.

At this moment, the alarm activation circuit 12 is activated. )
, a lamp, a buzzer, etc. are activated to warn the user that the light source has reached the end of its life and that the light source needs to be replaced.

(E) Effects of the Invention This invention has the effects listed in 1., since it has a structure that overcomes the effects described in 2.

You can know when to replace the light source, which cannot be seen with the naked eye.

If a reading error occurs, you can tell whether the cause of the error is due to deterioration of the light source.

A more correct way to use it is to strictly set a constant value γ, especially when high reading accuracy is required, to prevent reading errors caused by Jζ due to light source deterioration.

Furthermore, by setting γ between 11 and 6 for other platforms, the C light source can be used up to its maximum usable limit.

[Brief explanation of the drawing]

FIG. 1 shows an example of a conventional optical reading device, and FIG. 2 shows an example of the optical reading device of the present invention.
Fig. 079.

Claims (1)

[Claims] The light source, lens J3 and photoelectric conversion element are included! In an optical reading device with a 4M configuration, it is possible to read characters and symbols by operating the hand ski.
Means is provided for transmitting the force signal of the photoelectric photoelectric conversion element jq to the recognition section, and for determining the difference from a constant value, and controlling the light emission of the light source based on this difference, and for the light emission amount control means ( The operating amount of the light source is compared with a fixed value (independent of the above-mentioned fixed value), and if the operating amount exceeds the fixed value, the lens, lens, etc. are driven, and the light source performance deteriorates. An optical reading device characterized by providing a means to warn of the possibility of failure.￥1ffn1.
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