JPH11120283A - Optical information reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adequately read optical information at various depth (distance between a read opening and an object to be read) by a large-depth optical information reader which can accurately read out optical information larger than the diameter of the read opening. SOLUTION: The light receiving element 26a and 26d of an optical sensor 36 which correspond to the peripheral part can accumulate light a time T1-T2 longer than light receiving elements 26b and 26c corresponding to the center part under such control that two red light emitting diodes 26b and 26c for emitting the control part of a bar card 8 are turned on for a specific illumination time T2 in the exposure time T1 of the light receiving elements of the optical sensor 36 and then turned off, so an illuminance distribution along the width of the read opening can be made proper by adjusting the illumination time T2. Consequently, the amplitude of waveform data inputted after the illumination point T2 is set is analyzed to find and set an illumination time T2 with which proper waveform is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of irradiating an object to be read such as a bar code with light and reading an image of the object to be read from its reflected light. It relates to a possible optical information reader.

[0002]

2. Description of the Related Art A reflected light of light emitted from a light emitting means such as a light emitting diode onto a bar code attached to a product or the like is imaged on a light receiving means in which light receiving elements are arranged. 2. Description of the Related Art An optical information reading device that reads an image of a barcode is known.

Usually, such an optical information reading apparatus transmits light from a light emitting means through a reading port while a reading port provided in a case of the optical information reading apparatus is almost in contact with the bar code. , And the light reflected from the bar code is guided into the case of the optical information reading device from the same reading port, and forms an image on the light receiving means.

In such an optical information reading apparatus, it is necessary to bring the optical information reading apparatus to a product to which a bar code is attached, so that there is a problem that the reading operation is troublesome. In order to solve this problem, not only a bar code existing near the reading opening of the optical information reading device but also a bar code distant from the vicinity of the reading opening by several tens cm (for example, 30 to 50 cm) to the light receiving means. By imaging and reading, without having to perform the operation of bringing the optical information reading device closer to the product for each reading,
A so-called large-depth optical information reader that can efficiently read a barcode is conceivable.

However, a bar code irradiating lens is set so that the light emitted from the light emitting means used in a normal bar code is radiated from the entire reading opening. This is because when reading a bar code almost in contact with the reading port, the case of the optical information reading device becomes a blind spot and the bar code becomes difficult to see. This is to ensure that the light beam strikes the bar code even if it is slightly displaced. But,
When the barcode irradiating lens is set so as to spread the irradiation light so as to irradiate from the entire reading opening in this manner, only a very weak light reaches the position of the barcode far from the reading opening, and the barcode is not illuminated. It is not clear whether the reading port is directed to the bar code to be read or not, and there is a risk that reading may be mistaken.

Accordingly, as disclosed in, for example, Japanese Patent Application Laid-Open No. 6-236452, the intensity of reflected light incident on the image pickup means is detected, and the exposure time of the image pickup means is controlled based on the detection result. It has been conceived to always stabilize the amount of reflected light for the imaging means to convert video information into electrical signals. With this configuration, the optical information can be read without bringing the reading opening into contact with the reading target, and the readable range of the optical information can be increased as the reading opening is separated from the reading target. In addition, a wide range of optical information can be read without being limited by the diameter of the reading port.

[0007]

The causes of the deterioration of the reading performance when the reading port is separated from the reading object include not only the decrease in the intensity of the reflected light but also the problem of the illuminance distribution. That is, as shown in FIG.
No matter how flat the illuminance distribution of the irradiation light from the light emitting means is, when the reflected light is imaged on the light receiving element through the imaging lens, the amplitude of the reflected light waveform decreases as it goes to the periphery. Become. This is due to the COS ⁴ law and MTF characteristics of the imaging lens.

In this regard, conventionally, for example, the light emitting means has been designed so that the illuminance distribution of the irradiation light is brighter in the periphery than in the center. For example, assuming that four light emitting diodes are arranged as light emitting means, the both ends of the reading port are made denser than the central part, or the irradiation direction of the four light emitting diodes is inclined to both ends of the reading port. Accordingly, a device for increasing the luminance of the peripheral portion of the reading target has been considered.

[0009] However, these can only cope with a case where a bar code to be read exists at a certain specific position. That is, the degree to which the amplitude of the reflected light waveform decreases as it goes to the periphery changes according to the change in the distance between the reading port and the barcode. Therefore, even if the arrangement and the light amount of the light emitting diodes are adjusted so as to obtain an appropriate illuminance distribution in a state where the distance between the reading port and the barcode is L1, the distance between the reading port and the barcode is actually increased when reading. If it changes to L2, there is a possibility that the illuminance distribution may not be appropriate in that state.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and a large-depth optical information reading apparatus capable of accurately reading optical information having a diameter equal to or larger than the diameter of a reading port has various depths (from the reading port to the object to be read). It is an object of the present invention to provide an optical information reading apparatus capable of appropriately reading optical information at a distance).

[0011]

In order to achieve the above object, the optical information reading apparatus according to the first aspect of the present invention is directed to an optical information reading apparatus, which irradiates light emitted from a light emitting means through a reading opening of the case. By irradiating the object to be read outside the case from, the reflected light from the object to be read forms an image on the light receiving means inside the case through the reading port, and the light receiving means reads the image of the object to be read. A determination unit for determining whether an image forming state of the light receiving unit is appropriate in terms of an illuminance distribution and a received light amount in a width direction of the reading opening, and being inappropriate in terms of the illuminance distribution. In this case, the light amount control for the light emitting unit is performed so as to approach a predetermined ideal illuminance distribution, and when the light receiving amount is small and inappropriate, the exposure time of the light receiving unit is increased. Characterized by comprising a correction means for performing a process of increasing the amount of light received.

The case where the image forming state of the light receiving means has an ideal illuminance distribution is a state in which the illuminance distribution in the width direction of the reading opening is uniform (the amplitude of the reflected light waveform is uniform). As described above, no matter how flat the illuminance distribution of the irradiation light from the light emitting unit is, when the reflected light passes through the imaging lens and forms an image on the light receiving element, the COS ⁴ law of the imaging lens and the MTF Due to the characteristics and the like, the amplitude of the reflected light waveform decreases as it goes closer to the periphery. Therefore, in order to make the illuminance distribution uniform at the time of image formation on the light receiving means, roughly speaking, when viewed in the width direction of the reading opening, the illuminance of the illuminating light becomes brighter at the periphery than at the center when viewed in the width direction of the reading opening. It is necessary to control the light emitting means so as to obtain a distribution.

However, simply setting the light-emitting means in a fixed manner so that the illuminance distribution of the illuminating light becomes brighter at the periphery than at the center only when the bar code to be read exists at a specific position. I can not cope. That is, the degree to which the amplitude of the reflected light waveform decreases as it goes to the periphery changes according to the change in the distance between the reading port and the barcode. This is due to the characteristics of the optical system (such as the degree of diffraction and image blur) and the surrounding environment. Therefore, even if the arrangement and the light amount of the light emitting diodes are adjusted so as to obtain an appropriate illuminance distribution in a state where the distance between the reading port and the barcode is L1, the distance between the reading port and the barcode is actually increased when reading. If it changes to L2, there is a possibility that the illuminance distribution may not be appropriate in that state.

Also, if the light receiving amount in the light receiving means does not have a certain level, accurate reading of optical information cannot be performed. The amount of received light also changes as the distance between the reading port and the bar code changes. Therefore, according to the present optical information reading apparatus, the determining means determines whether or not the imaging state of the light receiving means is appropriate in terms of the illuminance distribution and the amount of received light in the width direction of the reading opening. That is, it is determined whether or not the imaging state of the light receiving unit under the actual reading state reflecting the distance to the reading target and the surrounding environment (particularly, the surrounding illuminance) is appropriate. For example, the light amount control is performed on the light emitting means so as to approach the ideal illuminance distribution. If the light receiving amount is inappropriate because the light receiving amount is small, the exposure time of the light receiving means is lengthened to increase the light receiving amount.

By doing so, it is possible to appropriately read optical information at an arbitrary depth (the distance from the reading port to the reading object). As the light emitting means, for example, a point light source in which three or more light emitting diodes are arranged can be cited. If the number is three, it is conceivable to arrange one at the center and near both ends in the width direction of the reading port, and the light amount of the light emitting diodes near both ends is larger than that at the center. Then, as described above, as the distance to the object to be read changes, the degree of increasing the light amount of the light emitting diodes near both ends as compared with the central light emitting diode also changes.

The light amount control by the correction means includes:
The control may be performed by controlling the energy supplied to the light emitting means, or by increasing the light emitting time of the light emitting means within a time zone in which the light receiving means can receive light. Regarding the process of increasing the exposure time of the light receiving means by the correction means, if the exposure time of the light receiving means is limited by the shutter, the exposure time may be increased by increasing the time for opening the shutter. it can.

When the determination means determines whether or not the illuminance distribution is appropriate, the output waveform from the light receiving means corresponds to the amplitude corresponding to the central portion in the width direction of the reading port and the end portion. It is conceivable to carry out based on the ratio with the amplitude. Further, the optical information reading device according to claim 7 irradiates the light from the light emitting means to the object to be read outside the case from the inside of the case through the reading opening of the case, thereby reading the reflected light from the object to be read. An optical information reading device that forms an image on a light receiving unit inside a case through an opening and reads an image to be read by the light receiving unit, and forms an image with the light receiving unit when a reading target for sampling is used. A control in which a light amount control value for the light emitting unit when the image state has an appropriate illuminance distribution in the width direction of the reading port is stored in correspondence with a plurality of sampling positions at which the distance from the reading port is sequentially changed. Value storage means, a distance sensor that measures a distance from the reading port to the reading target,
Control means for reading the light quantity control value corresponding to the distance to the object to be read measured by the distance sensor from the control value storage means, and performing light quantity control on the light emitting means based on the light quantity control value. It is characterized by.

According to the optical information reading apparatus of the present invention, the control value storage means is provided so that the image forming state of the light receiving means when the reading object for sampling is used has an appropriate illuminance distribution in the width direction of the reading opening. Light amount control value for the light emitting means,
It is stored corresponding to a plurality of sampling positions where the distance from the reading port is sequentially changed. As described above, the light emitting means is set so that the illuminance distribution of the irradiation light is brighter in the peripheral portion than in the central portion in the width direction of the reading opening.
The degree to which the amplitude of the reflected light waveform decreases as it goes to the periphery changes according to the change in the distance between the reading port and the barcode. Therefore, the light amount control value for the light emitting unit when the image forming state of the light receiving unit is appropriate in the width direction of the reading opening when the reading opening has a reading target for sampling, and the light amount control value of the distance L1 (> 0) from the reading opening. The distance from the reading port, such as the light quantity control value when there is a sampling reading target at the position, the light quantity control value when the sampling reading target is at a distance L2 (> L1) from the reading port, and so on. Light amount control values are stored in correspondence with the plurality of sampling positions that are sequentially changed.

During the actual reading operation, the distance sensor measures the distance from the reading opening to the object to be read, and the control means controls the light amount control value corresponding to the measured distance to the object to be read by the control value. The light quantity is read from the storage means, and the light quantity control for the light emitting means is performed based on the light quantity control value. In the actual reading operation, it is assumed that the distance h from the reading port to the reading target is not exactly L1 or L2, but for example, 0 <h ≦ L
In the case of 1, the light amount control value at L1 is used, and L1 <h ≦ L
In the case of 2, the light amount control value at L2 may be used. Further, the light amount control values at other distances may be obtained by interpolation using the light amount control values at distances 0, L1, and L2.

In the optical information reading device according to the present invention (also referred to as a second optical information reading device), it is possible to appropriately read optical information at various depths (distances from a reading opening to a reading target). However, when compared with the above-described optical information reading device according to claim 1 (also referred to as a first optical information reading device), there are the following advantages and disadvantages, respectively. In the case of the first optical information reading device, it is determined whether or not it is appropriate in terms of the illuminance distribution and the amount of received light. If the control is performed and the amount of light received is small, and it is inappropriate, feedback control is performed to increase the amount of light received by increasing the exposure time of the light receiving means. It causes a reduction in speed. On the other hand, in the case of the second optical information reading device, since it can be uniquely controlled based on the detected distance, the reading speed is expected to be improved as compared with the first optical information reading device using feedback control. it can. Conversely, the first optical information reading device does not require a distance sensor, and the second optical information reading device requires a “light amount corresponding to a plurality of sampling positions where the distance from the reading port is sequentially changed. The process of “storing the control value” is unnecessary. Further, since the first optical information reading apparatus performs control based on the image forming state at the time of reading, it can cope with factors other than the distance, and more appropriate control can be realized. In other words, even at the same distance, for example, the bar width when the object to be read is a barcode, the ambient illuminance (when only half of the object to be read is exposed to disturbance light, etc.), or the diffraction or best focus The imaging state changes due to blur or the like based on the deviation. Even in such a situation, since the first optical information reading device controls based on the imaging state at the time of reading, appropriate control can be realized.

The light quantity control value stored in the control value storage means may be stored as a control value of the energy supplied to the light emitting means, or may be a time period during which the light receiving means can receive light. It may be stored as a control value of the light emitting time of the light emitting means within the band.

In the case where the exposure time control for the light receiving means is performed in addition to the light quantity control, the control value storage means may appropriately control the image forming state of the light receiving means when using a reading object for sampling. Exposure time control values for the light receiving means in the case of realizing a large amount of received light may be stored corresponding to a plurality of sampling positions. This way,
The control unit reads a light amount control value and an exposure time control value corresponding to the distance to the reading target from the control value storage unit,
The light amount control for the light emitting means can be performed based on the light amount control value, and the exposure time control can be performed based on the exposure time control value.

When the exposure time of the light receiving means is limited by the shutter, the control value of the shutter opening time may be stored in the control value storage means as the exposure time control value. On the other hand, in the optical information reading apparatus according to the twelfth aspect, the reflected light from the reading target is read by irradiating the irradiation light from the light emitting means from the inside of the case to the reading target outside the case through the reading port of the case. An optical information reading device that forms an image on a light receiving unit inside a case through an opening and reads an image to be read by the light receiving unit, wherein the amplification unit amplifies an output waveform of the light receiving unit at a predetermined amplification factor. Means, a light amount control value for the light emitting means when the imaging state of the light receiving means when using a reading object for sampling is an appropriate illuminance distribution in the width direction of the reading opening, An exposure time control value for the light receiving means when the imaging state is realized with an appropriate amount of received light, and the amplification factor when the amplified output from the amplifying means is realized at an appropriate level A control value storage means storing a set corresponding to a plurality of sampling states in which the distance from the reading port and the surrounding illuminance are sequentially changed; and reading and reading one set of control values from the control value storage means. Controlling the light amount of the light emitting unit based on the light amount control value, controlling the exposure time of the light receiving unit based on the read exposure time control value, and controlling the amplifying unit to be the read amplification factor. If the image to be read cannot be read normally after the control, a control means for reading another set of control values and performing the same control is provided.

According to the present optical information reading apparatus, the control value storage means is provided for controlling the case where the image formation state of the light receiving means when the reading object for sampling is used has an appropriate illuminance distribution in the width direction of the reading opening. The light amount control value for the light emitting unit, the exposure time control value for the light receiving unit when the imaging state of the light receiving unit is realized with an appropriate light receiving amount, and the amplified output from the amplifying unit are realized at appropriate levels. The amplification factor in the case is stored as a set corresponding to a plurality of sampling states in which the distance from the reading port and the surrounding illuminance are sequentially changed. The control means reads one set of control values from the control value storage means, performs light amount control on the light emitting means based on the read light amount control value, and performs exposure time control on the light receiving means based on the read exposure time control value. Control is performed to control the amplification means so that the read amplification factor is obtained. If the image to be read cannot be read normally after the control, another control value for another set is read and similar control is executed. I do.

In the present optical information reading apparatus (also referred to as a third optical information reading apparatus), as in the case of the second optical information reading apparatus, a plurality of samplings in which the distance from the reading port and the ambient illuminance are sequentially changed. The control values are stored according to the state, and the light amount control value, the exposure time control value, and the amplification factor are stored as a set. In the actual reading operation, the second optical information reading device reads the corresponding control value based on the distance measured by the distance sensor. However, in the case of the third optical information reading device, Does not measure distance. That is, the control value for one set is read to control the light amount, the exposure time, and the amplification factor for the amplifying means. If the image to be read cannot be read normally after the control, another set of control values is read. Is performed, and the same control is executed and the feedback control is performed.

In the case of the third optical information reading device,
Although there is an advantage that the distance sensor is unnecessary, the reading target is limited to some extent. For example, in the case of reading objects of the same standard, such as a bar code attached to a mail, the size and color contrast are almost the same, and matching between sampling and actual reading can be obtained. If any one set of control values (light amount control value, exposure time control value, and amplification factor) is used, the image to be read can be read normally.

The light amount control value stored in the control value storage means may be stored as a control value of the energy supplied to the light emitting means, or may be a time period during which the light receiving means can receive light. It may be stored as a control value of the light emitting time of the light emitting means within the band. When the exposure time of the light receiving means is limited by the shutter,
The control value of the shutter opening time may be stored as the exposure time control value in the control value storage means.

The object to be read by the above-described optical information reading apparatus may be, for example, a bar code, but is not limited thereto, and may be, for example, a two-dimensional code.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] FIG. 1 is a schematic configuration diagram of an optical information reading apparatus 4 as a first embodiment to which the above-described invention is applied.

In the present embodiment, the optical information reading device 4 is configured as a so-called bar code reader handy terminal. FIG. 1 is a schematic sectional view of the optical information reading device 4, and FIG. 2 is a block diagram of a control system thereof. The optical information reading device 4 includes a case 12, a reading unit 14, a data processing output unit 16, and a power supply unit 18.

A reading unit 14 is provided inside the front part of the case 12.
Are arranged, and a rear portion of the case 12 forms a grip portion 20 for an operator to grip with a hand. In the lower part of the front part of the case 12, a reading port 22 which is long in the left and right (in the direction perpendicular to the paper surface in FIG. 1), that is, is long in the width direction, is provided. , The reading port 22 is closed. As a result, the dust is
2 to prevent it from entering the inside of the case 12. Further, the dustproof plate 24 can pass at least red light as reading light described below.

The reading section 14 includes an illumination red light emitting diode 26 (corresponding to a light emitting means), a light emission driving circuit 28, a bar code irradiation lens 30, a reflecting mirror 32, an imaging lens section 34, and an optical sensor 36 (light receiving means). Applicable). When the illumination red light emitting diode 26 emits light by the light emission drive circuit 28, the red light passes through the dustproof plate 24 and irradiates the bar code 8 outside the case 12. In FIG. 1, the bar arrangement direction of the bar code 8 and the width direction of the reading port 22 are aligned, and the bar code 8 is almost in contact with the reading port 22 as shown by a solid line in FIG. The case where the bar code 8 is irradiated is shown. Of course, as shown by the broken line in FIG. 1, the reading may be performed with the reading opening separated from the barcode 8.

The red light reflected by the bar code 8 is
Again, the dust enters the case 12 from the dust-proof plate 24, is reflected by the reflecting mirror 32, and incorporates a vertically elongated aperture 34a shown in the enlarged perspective view of FIG. 3A and the enlarged sectional side view of FIG. 3B. The image of the bar code 8 is incident on the image lens unit 34, and passes through the vertically long aperture 34 a and the imaging lenses 34 b and 34 c, and the image of the bar code 8 is applied to the optical sensor 36 in which the light receiving elements are linearly arranged in a line. An image is formed in the same direction in which the light receiving elements of the optical sensor 36 are arranged. An optical sensor 36 that reads the image of the barcode 8 by photoelectric conversion.
Is output to the data processing output unit 16 as an electric signal representing an image pattern.

The longitudinal aperture 34a built in the imaging lens unit 34 is disposed closer to the reading port 22 than the imaging lenses 34b and 34c, and its longitudinal direction is the same as the longitudinal direction of the bar of the bar code 8. The barcode 8 is set to be read in a state where the barcodes match. The image forming system including the reflecting mirror 32 and the image forming lens unit 34 includes at least the position of the reading opening 22 and the bar code 8 extending from the position of the reading opening 22 to a position several tens of cm (for example, 30 to 50 cm) away. Is configured as an imaging system with a large depth so that the image can be read.

The optical sensor 36 uses an image sensor for reading a document of a facsimile apparatus in which light receiving elements are arranged in a line and each light receiving element has an aspect ratio of approximately "1". Data processing output unit 1 inside case 12
6 includes an amplification circuit 41 (corresponding to amplification means), a memory 42 (corresponding to control value storage means), a binarization circuit 43, and a microcomputer 44 (corresponding to judgment means, correction means and control means) on a substrate 38. ), A peak hold circuit 45, and an output circuit 46 to a main unit such as a register or a host computer. The data processing output unit 16
When read data of the bar code 8 is input from the reading unit 14 via the amplifier circuit 41 and the binarization circuit 43, the data is decoded (decoded) by the processing of the microcomputer 44, and the bar code 8 is displayed. Information is obtained, and the information is temporarily stored in the memory 42. Next, the information stored in the memory 42 is output by the output circuit 46.
It is transmitted to the main unit as a serial signal. In this embodiment, wired communication is used, but wireless communication using light or radio waves may be used.

In the portion where the reading section 14 is stored,
A buzzer device 48 is provided at a position not affecting the optical path,
When the microcomputer 44 succeeds in decoding the bar code 8, the buzzer device 48 sounds. In the power supply section 18, a battery 18a is housed as a power supply.

The microcomputer 44 has a well-known CP.
U, ROM, RAM, I / O, and the like are provided to execute necessary processing as the data processing output unit 16 described above. Here, the optical arrangement state is schematically shown in FIG. The illumination red light emitting diode 26 described in FIG. 1 is actually composed of four illumination red light emitting diodes 26a, 26b, 26c, 26d as shown in FIG.
Irradiation light from these is passed through the condenser lens 30 to the reading port 2.
From 2, the bar code 8 existing outside the case 12 is irradiated.

The red light emitting diodes 26a, 26 for illumination
Although b, 26c and 26d are arranged side by side in the width direction of the reading opening, both end sides of the reading opening 22 are made denser than the central portion. This is because the illumination light from the illumination red light emitting diodes 26a, 26b, 26c, 26d makes the illuminance at the peripheral portion larger than at the central portion on the bar code 8 to be read. In addition, as shown in FIG. 4B, the red light emitting diodes 26a, 26b, 26 for illumination are used.
It is also conceivable to incline the irradiation directions of c and 26d toward both ends of the reading port 22 so as to increase the illuminance in the peripheral portion of the reading target.

As described above, the red light emitting diode 2 for illumination
The reason that the illuminance of the irradiation light from 6a, 26b, 26c, and 26d on the bar code 8 to be read is higher in the peripheral portion than in the center portion is that the reflected light is no matter how flat the illuminance distribution of the irradiation light is. Is formed on the optical sensor 36 through the imaging lens unit 34, the imaging lens unit 3
This is to cope with the fact that the amplitude of the reflected light waveform decreases toward the periphery as shown in FIG. 5A due to the COS ⁴ law, MTF characteristics, etc.

However, these methods can only cope with a case where a bar code to be read exists at a specific position. That is, the degree to which the amplitude of the reflected light waveform decreases as it goes to the periphery changes according to the change in the distance between the reading port 22 and the barcode 8. Therefore, for example, as shown by a solid line in FIG.
Even if the adjustment is made based on the case where the bar code 8 is irradiated in a state where the reading port 22 is almost in contact with the reading port 22, it is inappropriate when the reading port 22 is separated from the bar code 8 as shown by a broken line in FIG. Becomes Therefore, when the reading port 22 is separated from the barcode 8, the illumination intensity distribution of the illumination light must be appropriately adjusted according to the distance.

In view of this point, in the present embodiment, the light emission drive circuit 28 is configured so as to be able to control the light amount of each of the illumination red light emitting diodes 26a, 26b, 26c, 26d. This light emission drive circuit 28 is, for example, as shown in FIG.
(26b, 26c, 26d) and a power supply Vcc, a limiting resistor R is provided, and a red light emitting diode 26a (2
6b, 26c, 26d), the transistor T
R is connected. The limiting resistor R and the transistor TR correspond to the light emission drive circuit 28. When the illumination red light emitting diode 26a (26b, 26c, 26d) emits light, the microcomputer 44 outputs an emission signal P to the transistor TR, so that the current is supplied to the illumination red light emitting diode 26a (26b, 26c, 26d). Flows to emit light.

It is necessary to finally determine whether or not the illuminance distribution of the illumination light is appropriate based on the output from the optical sensor 36. In order to do this, in the present embodiment, the peak of the waveform is found by the peak hold circuit 45 to determine what the output waveform from the optical sensor 36 is, and the microcomputer 44 compares the amplitude of the output waveform. ing.

Here, the peak hold circuit 45 will be described with reference to FIG. A predetermined reference voltage is applied to the non-inverting input of the OP amplifier 45a, and the output from the amplifying circuit 41 is applied to the inverting input via a capacitor C1 and a resistor R1 arranged in series. Is a microcomputer 44 via a diode D1.
Is input to A diode D2 is connected in parallel between the capacitor C1 and the resistor R1 and the output of the OP amplifier 45a, while the diode D2 is connected between the diode D1 and the microcomputer 44 and the inverted input of the OP amplifier 45a. Is connected in parallel with a resistor R2. In addition,
A reference voltage is applied between the diode D1 and the microcomputer 44 via a capacitor C2.

The optical information reading apparatus 4 of the present embodiment having the above-described configuration analyzes the output waveform from the optical sensor 36, and as shown in FIG. Output V1 of the peripheral part in the region D to be imaged
When the ratio between the output and the output V2 at the central portion is large, the light amount of the red LED 26 for illumination is controlled so that the output V3 at the peripheral portion is almost equal to the output V4 at the central portion as shown in FIG. Try to be about the same. This is the optical sensor 3
Exposure time of the light receiving element at 6 is shown by T in FIG.
If it is 1, for example, 2 for illuminating the central portion of the bar code 8 in FIG.
10 red light emitting diodes 26b and 26c
After turning on the light for the lighting time T2 shown in FIG. In this manner, in the light receiving element of the optical sensor 36, the light receiving element corresponding to the peripheral portion can store light longer than the light receiving element corresponding to the central portion by the time T1−T2, so that the lighting time T2 Is adjusted, it is possible to make the output V3 in the peripheral portion substantially the same as the output V4 in the central portion as shown in FIG. 5B.

If the output from the optical sensor 36 is too small, the binarization circuit 43 does not properly binarize the data. As a result, the information of the bar code 8 cannot be read properly. Exposure time T1 in sensor 36
Is controlled to be longer. When the exposure time T1 is lengthened, the light receiving time of the light receiving element of the optical sensor 36 is lengthened, and the amount of accumulated charge is increased accordingly, so that the output level from the optical sensor 36 is increased as a whole. As described above, within the predetermined exposure time T1, the two illumination red light emitting diodes 26b and 26c for illuminating the central portion of the barcode 8 are turned on for the lighting time T2 shown in FIG. 10B. Therefore, if the exposure time T1 is increased, the lighting time T2 is also increased at the same rate.

These controls are performed by the microcomputer 44
Is executed, so that processing will be described with reference to the flowchart of FIG. When the process is started, data acquisition is first performed (S110). This data capturing process is performed by the two illumination red light emitting diodes 26 for illuminating the central portion of the bar code 8 with the above-described exposure time T1.
The lighting operation is performed with the initial values set for the lighting times T2 of the b and 26c, and the optical sensor 36 based on the reflected light is used.
Is amplified by an amplifier circuit 41, the amplified signal is binarized by a binarization circuit 43, and the binarized signal is decoded by a microcomputer 44.

If decoding is possible (S120: Y
ES), this process is terminated as it is, but if decoding was not possible (S120: NO), S130 to S18
At 0, the lighting time T2 and the exposure time T1 are controlled. First, in S130, amplitude data is fetched. As described above, as described above, the peak of the output waveform (the output waveform from the amplifier 41) is found by the peak hold circuit 45, and the peak value is taken in as amplitude data. Then, in S140, the amplitude of the waveform data is analyzed. That is, the amplitude data of the output waveform for one barcode 8 is fetched, and the amplitude V1 of the peripheral portion and the amplitude V2 of the central portion shown in FIG. 5A are compared, and their ratio (V2 / V1) is obtained. Determine if it is in the proper range. For example, when the amplitude ratio (V2 / V1) is a value of 2 or 3, the amplitude of the peripheral portion is considerably smaller than that of the central portion, and the illuminance distribution is poor. Therefore, it is considered that this poor illuminance distribution is one of the reasons why decoding could not be performed, so that the LED lighting control is executed in S150. As described above, this control is performed by the two illumination red light emitting diodes 26b and 26c for illuminating the central portion of the bar code 8 within the exposure time T1 of the light receiving element in the optical sensor 36 as shown in FIG. Is turned on after turning on for the lighting time T2 shown in FIG. With this control, in the light receiving element of the optical sensor 36, the light receiving element corresponding to the peripheral portion can store light longer than the light receiving element corresponding to the central portion by the time T1-T2, so that the lighting time T2 is adjusted. Then, as shown in FIG. 5 (b), it is possible to make the output V3 at the peripheral portion substantially the same as the output V4 at the central portion.

The amplitude analysis is also performed on the waveform data acquired after the lighting control in S150, and it is determined whether or not the waveform is appropriate (S160). In this determination, as described in S140, the amplitude data of the output waveform is fetched, and the ratio (V2 / V1) of the amplitude V1 of the peripheral portion and the amplitude V2 of the central portion shown in FIG. It depends on whether there is. If the waveform is not appropriate, the LED lighting control is performed again in S150. Specifically, in this LED lighting control, it is conceivable that the lighting time T2 is sequentially shortened from the initial value.

As described above, the lighting time T2 is changed and controlled, and when the output waveform is in an appropriate state (S16
0: YES), and proceeds to S170 to determine whether the minimum value of the amplitude is greater than or equal to a predetermined determination value. This is because if the entire output waveform is too small, the binarization circuit 43 appropriately selects
Since the information is not converted to a value and the information of the barcode 8 cannot be appropriately read as a result, it is determined whether or not the information is equal to or larger than a determination value for properly reading.

If a negative determination is made in S170, that is, if the minimum value of the amplitude is smaller than the predetermined determination value, exposure time control is performed in S180. This is, as described above, a control for increasing the exposure time T1 in the optical sensor 36. If the exposure time T1 is increased, the lighting time T2 is increased at the same rate.
Also lengthen. In this exposure time control, specifically, it is conceivable that the exposure time T1 is increased by a predetermined value from the initial value, and accordingly, the lighting time T2 is also increased at the same rate.

The amplitude analysis is also performed on the waveform data acquired after the exposure time control in S180, and it is determined whether or not the minimum value is equal to or larger than the determination value (S17).
0). If an affirmative determination is made (S170: YE
S), and return to S120. As described above, according to the optical information reading device 4 of the present embodiment, it is determined whether or not the imaging state of the optical sensor 36 is appropriate in terms of the illuminance distribution and the amount of received light in the width direction of the reading port 22 ( S160, S1
70) two illuminations for illuminating the central portion of the bar code 8 within the exposure time T1 of the light receiving element in the optical sensor 36 so as to approach the ideal illuminance distribution if the illuminance distribution is inappropriate. Red light emitting diodes 26b, 26c
(S150), and if the received light amount is small and inappropriate, the exposure time T1 is lengthened to increase the received light amount.

In this manner, optical information at an arbitrary depth (the distance from the reading port 22 to the bar code 8 to be read) can be appropriately read. Further, in the case of the present embodiment, since the control is performed based on the image formation state of the optical sensor 36 at the time of actual reading, it is possible to cope with factors other than the depth as a result, and more appropriate control is performed. Can be realized. That is, even if the depth is the same, for example, the blur based on the width of the bar of the bar code 8, the ambient illuminance (for example, when only half of the bar code 8 is disturbed), or the deviation from the diffraction or the best focus. The imaging state changes depending on the conditions. Even in such a situation, the optical information reading device 4 performs control based on the image forming state at the time of reading, so that appropriate control can be realized.

Further, other ripple effects include the following. For example, as the control of the lighting time T2, in the above description, it has been described that the two illumination red light emitting diodes 26b and 26c for illuminating the central portion of the barcode 8 are turned on for the lighting time T2 and then turned off. That is, two red light emitting diodes 26b and 26 for illumination for illuminating the central portion.
The lighting time of c is T2, and the lighting time of the remaining two illumination red light emitting diodes 26a and 26d for illuminating the peripheral portion is T2, which is the same as the exposure time.
And two peripheral times. However, four red light emitting diodes 26a, 26b,
The lighting time for 26c and 26d may be individually controlled. In this way, even if, for example, there is a hardware variation in luminance among the four red light emitting diodes for illumination 26a, 26b, 26c, 26d, the influence of the variation can be absorbed.

The effect of specular reflection can be reduced. For example, after the specular reflection is detected by the peak hold circuit 45 described above, the illumination red light emitting diodes 26a, 26b,
If reading using the surrounding brightness is performed by extending the time during which the lights 26c and 26d are turned off or by performing dimming control, reading cannot be performed due to specular reflection in a normal reading operation. Reading is possible even in the situation.

In the first embodiment, steps S160 and S170 in the flowchart of FIG. 9 correspond to the processing as the determination means, and steps S150 and S170
180 corresponds to the processing as the correction means. [Embodiment 2] In the case of the optical information reading apparatus 4 according to Embodiment 1, since the feedback control based on the imaging state at the time of reading is performed, the control time becomes relatively long and the reading is performed. Tends to reduce speed. Thus, an optical information reading apparatus according to the second embodiment, which particularly emphasizes the reading speed, will be described.

The optical information reading apparatus according to the second embodiment
A configuration in which a distance sensor 150 (see FIG. 10) is added to the configuration provided in the optical information reading device 4 according to the first embodiment described above. As the distance sensor 150, for example, an active triangulation or a pyroelectric infrared sensor may be used. For example, as a distance sensor using a triangulation method, an LED for light emission and a plurality of photodiodes for light reception are arranged side by side, and the intensity of light reflected from the LED by light emitted from the LED is reflected by a plurality of light emitting diodes. It is known that the distance is measured by detecting with a photodiode. That is,
When the distance is relatively close, the reflection angle is large,
The output of the photodiode on the side farther from the LED increases, and the output of the photodiode on the side closer to the LED increases because the reflection angle is small when the photodiode is relatively far away. Distance measurement is performed based on this principle. Of course, the bar code 8 to be read is not limited to these.
Any other method may be used as long as it can measure the distance to it.

The remaining structure is basically the same as the structure of the optical information reading device 4 of the first embodiment.
It will not be described in detail. The optical information reading apparatus according to the second embodiment emits red light for illumination when the imaging state of the optical sensor 36 when the sampling barcode is used has an appropriate illuminance distribution in the width direction of the reading port 22. Light amount control values (the lighting time T2 in this case) for the diodes 26a, 26b, 26c, and 26d are stored in the memory 42 corresponding to a plurality of sampling positions where the distance L from the reading port 22 is sequentially changed. At the time of the actual reading operation, the distance sensor 150 measures the distance from the reading port 22 to the barcode 8, reads the lighting time T2 corresponding to the measured distance from the barcode 8 from the memory 42, and controls the lighting time T2. The control based on the value is performed.

First, a process for storing the lighting time T2 as a control value will be described. It is conceivable that this control value storage processing is performed, for example, at the time of factory shipment. Since this is executed by the microcomputer 44, its processing will be described with reference to the flowchart of FIG.

When the process is started, it is determined whether or not a sampling label is arranged at a predetermined sampling position (S210). For example, it is conceivable that the operator performing the initial setting gives an instruction by pressing an operation button (not shown). In this case, the setting is completed when the operation button is pressed (S210: YES), and S2 is performed.
Move to 20.

In S220, the distance sensor 150 acquires the distance to the sampling label at the sampling position described above. This distance is measured as the distance from the reading port 22 to the sampling label. S2
After acquiring the distance to the sampling position at 20,
The process proceeds to S230 to control the lighting time T2. Specifically, each of the illumination red light emitting diodes 26a, 26b,
A number of lighting time T2 candidates are prepared for 26c and 26d, and a combination of these is finally set.

Since it is necessary to determine whether or not this setting is appropriate, it is determined in S240 whether or not the waveform is appropriate. In this determination, the peak of the output waveform (the output waveform from the amplification circuit 41 in this case) is found by the peak hold circuit 45, and the peak value is taken in as amplitude data. Then, the amplitude V1 of the peripheral portion shown in FIG.
The determination is made based on whether or not the ratio (V2 / V1) of the amplitude V2 at the center portion is within an appropriate range. If the waveform is not appropriate (S240: NO), another lighting time T is set again in S230.
2 is set. On the other hand, if the waveform is appropriate (S24
0: YES), at S250, the distance to the sampling position and the corresponding red LED 26a,
Each control value of the lighting time T2 for 26b, 26c, 26d is stored in the memory 42.

Then, in the following S250, it is determined whether or not the storage of the control values corresponding to all the sampling positions has been completed. If the storage has not been completed (S250: NO), S21 is executed.
Returning to 0, the control value storage processing at another sampling position (S220 to S240) is executed. In the present embodiment, as shown in FIG. 12A, control values are stored at four sampling positions whose distance from the reading port 22 is 0, a, b, and c. The magnitude relation of these four distances 0, a, b, and c is 0 <a <b <c.

When the setting of the control values at all four sampling positions is completed (S250: YES), the control value table of FIG. 12B corresponds to the distances 0, a, b, and c of the four sampling positions. The processing is terminated. Next, the processing in the actual reading operation will be described with reference to FIG.
This will be described with reference to the flowchart of FIG.

First, in the first step S310, the distance sensor 150 acquires the distance h to the barcode 8 to be actually read. And S3
In step 20, the distance h is determined, and any one of steps S330 to S360 is performed based on the determination result.

First, when h = 0, the lighting time T2 corresponding to the distance 0 is obtained from the control value table shown in FIG.
Is read. When 0 <h ≦ a, FIG.
The lighting time T2 corresponding to the distance a is read from the control value table shown in FIG.

In the case of a <h ≦ b, FIG.
The lighting time T2 corresponding to the distance b is read from the control value table shown in FIG. When b <h, FIG.
The lighting time T2 corresponding to the distance c is read from the control value table shown in FIG.

After reading the lighting time T2 in any one of S330 to S360, the process proceeds to S370 to control the exposure time T1. As described in the first embodiment, this is a control for increasing the exposure time T1 in the optical sensor 36, and the exposure time T1
, The lighting time T2 is also lengthened at the same rate.

After performing the exposure time control in S370, it is determined in S380 whether or not the data is fetched and decoded (S390). If the decoding has failed (S390: NO), S37
Returning to 0, the exposure time control is repeated. In this exposure time control, specifically, it is conceivable that the exposure time T1 is increased by a predetermined value from the initial value, and accordingly, the lighting time T2 is also increased at the same rate. On the other hand, if the decoding has been successful (S390: YES), this processing ends.

As described above, in the second embodiment,
Illuminating red light emitting diodes 26a, 26b, 26c in a case where the imaging state of the optical sensor 36 when the sampling barcode is arranged at a predetermined sampling position in advance has an appropriate illuminance distribution in the width direction of the reading port 22. , 2
Light amount control value for 6d (lighting time T2 in this case)
Is stored as a control value table shown in FIG. 12B as control values corresponding to a plurality of sampling positions where the distance from the reading port 22 is sequentially changed. At the time of the actual reading operation, a control value corresponding to the distance h from the reading port 22 to the barcode 8 measured by the distance sensor 150 is read from the control value table, and based on the control value, the lighting time T2 is determined. Perform control.

In the second embodiment, as in the first embodiment, optical information at various depths (distances from the reading port 22 to the barcode 8) can be appropriately read. However, the optical information reading device 4 of the first embodiment
Compared to, each has the following advantages and disadvantages. In the case of the optical information reading device 4 according to the first embodiment, since the feedback control is performed by actually detecting whether or not the light intensity is appropriate in terms of the illuminance distribution and the amount of received light, the control time becomes relatively long, and the reading time becomes longer. It causes a reduction in speed. On the other hand, in the case of the optical information reading device of the second embodiment,
Since the control can be performed uniquely based on the detected distance h, an improvement in the reading speed can be expected as compared with the case of the first embodiment using the feedback control. Conversely, a distance sensor 150 that is unnecessary in the optical information reading device 4 of the first embodiment is required. Further, in the case of the first embodiment, since the control is performed based on the image forming state at the time of reading, factors other than the distance can be dealt with, and more appropriate control can be realized. In such a case, it is basically possible to deal only with the factor based on the distance. Therefore, assuming use in a situation where the influence of factors other than the distance is small, the advantage of improving the reading speed is particularly effectively exhibited. [Third Embodiment] In the second embodiment, control values corresponding to a plurality of sampling states in which the distance from the reading port 22 and the surrounding illuminance are sequentially changed are stored in advance, and the distance sensor 150 is stored in the distance sensor 150 during actual reading. Although the control value corresponding to the measured distance is read out and used for control, it is also possible to perform control without using the distance sensor 150. That is, in the third embodiment, the control value is stored in correspondence with a plurality of sampling states in which the distance from the reading port 22 and the surrounding illuminance are sequentially changed. However, the distance itself is not stored, and the control value shown in FIG. As shown in the value table, the lighting time T2, the exposure time T1, and the amplification factor in the amplifier circuit 41 for the above-described illumination red light emitting diodes 26a, 26b, 26c, and 26d are stored as a set, and the data of each set includes N
O. 1 to N are attached. Then, in the actual reading operation, instead of reading out the corresponding control value based on the measured distance as in the above-described second embodiment, FIG.
Read out a set of control values from the control value table of
Red light emitting diodes 26a, 26b, 26c, 2 for illumination
The control of the lighting time T2 for 6d, the control of the exposure time T1 for the optical sensor 36, and the setting control of the amplification factor in the amplifier circuit 41 are performed, and after the control, it is determined whether or not the decoding was successful. If decoding is not properly performed, feedback control is performed to read another set of control values and execute the same control.

The optical information reading apparatus according to the third embodiment has an advantage that the distance sensor is unnecessary, but the object to be read is limited to some extent. For example, in the case of reading objects of the same standard, such as a bar code attached to a mail, the size and color contrast are almost the same, and matching between sampling and actual reading can be obtained. Any one set of control values (lighting time T
2, the exposure time T1 and the amplification factor), the image to be read can be read normally. [Others] In the above-described first to third embodiments, as a means for increasing the amount of light received by the optical sensor 36, the exposure time T
1 was increased, but as shown in the front view of FIG. 15A and the side view of FIG. 15B, two sheets were formed in the longitudinal direction of the longitudinal stop 34a of the imaging lens unit 34. A shutter 50 for raising and lowering the shielding plates 50a and 50b is provided.
The opening time of the shutter 50 is determined by the microcomputer 44.
May be controlled to increase the amount of received light. That is, instead of the exposure time T1, the shutter 50
By using the open time, the same processing can be performed.

Further, in each of the embodiments described above, the reader for the bar code 8 has been described. However, a two-dimensional code can be similarly configured, and the same effect can be obtained. In each of the above-described embodiments, the reading port 22 is provided as an opening in the front part of the case 12. However, the part along the bar code 8 is the case 1
If there is an opening 2 in addition to the opening, that portion corresponds to the actual reading opening 22 portion.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an optical information reading device according to a first embodiment.

FIG. 2 is a block diagram of a control system according to the first embodiment.

FIG. 3 is an explanatory diagram illustrating a configuration of an imaging lens unit according to the first embodiment;

FIG. 4 is an explanatory diagram showing an arrangement of a red light emitting diode for illumination as the first embodiment;

FIG. 5 is an explanatory diagram of a reflected light waveform formed on an optical sensor.

FIG. 6 is a circuit diagram showing a luminance adjustment mechanism of the red light emitting diode for illumination as the first embodiment;

FIG. 7 is a circuit diagram showing a peak hold circuit according to the first embodiment;

FIG. 8 is a time chart showing an exposure time T1 and a lighting time T2 of the illumination red light emitting diode in the optical sensor according to the first embodiment.

FIG. 9 is a flowchart illustrating control processing during reading including lighting time control and exposure time control according to the first embodiment.

FIG. 10 is a block diagram of a control system according to a second embodiment.

FIG. 11 is a flowchart illustrating a process of storing a control value according to the second embodiment.

FIG. 12 is an explanatory diagram of a sampling position and a control value table according to the second embodiment.

FIG. 13 is a flowchart illustrating control processing during reading according to the second embodiment.

FIG. 14 is an explanatory diagram of a control value table according to the third embodiment.

FIG. 15 is a diagram illustrating a configuration of a shutter according to another embodiment.

[Explanation of symbols]

4: Optical information reading device 8: Bar code 1
2 Case 14 Reading part 16 Data processing output part
18 power supply unit 18a battery 20 grip unit
Reference numeral 22: Reading port 24: Dust-proof plate 26 (26a, 26b, 26c, 26d): Red light emitting diode for illumination 28: Light emission drive circuit 30: Bar code irradiation lens 32: Reflecting mirror 34: Imaging lens unit 34
a: Vertical aperture 34b, 34c: Imaging lens 36: Optical sensor 38: Substrate 41: Amplifier circuit 4
DESCRIPTION OF SYMBOLS 2 ... Memory 43 ... Binarization circuit 44 ... Microcomputer 45 ... Peak hold circuit 46 ... Output circuit 4
8 buzzer device 50 shutter 50a, 50b shielding plate 15
0: Distance sensor

Claims (17)

[Claims] An illumination light from a light emitting means is irradiated from the inside of the case to a reading object outside the case through a reading port of the case, so that reflected light from the reading object is received inside the case through the reading port. An optical information reading device that forms an image on a unit and reads an image to be read by the light receiving unit, wherein an image forming state of the light receiving unit is appropriate in terms of an illuminance distribution and a received light amount in a width direction of the reading opening. Determination means for determining whether or not the light intensity distribution is unsuitable. If the light intensity distribution is inappropriate, light amount control is performed on the light emitting means so as to approach a predetermined ideal illumination distribution, and the light reception amount is small. An optical information reading apparatus, comprising: a correction unit that performs a process of increasing the amount of received light by increasing the exposure time of the light receiving unit if appropriate. 2. An optical information reading apparatus according to claim 1, wherein said correction means controls said light amount by controlling energy supplied to said light emitting means. 3. The method according to claim 1, wherein the correcting means performs a process of increasing the light quantity control by extending a light emitting time of the light emitting means within a time zone in which the light receiving means is in a light receiving state. The optical information reading device according to claim 1. 4. An exposure time of said light receiving means is limited by a shutter, and said correction means performs a process of increasing an exposure time by increasing a time for opening said shutter. 2. The optical information reading device according to 1. 5. The illuminance distribution is determined based on a ratio of an amplitude corresponding to a center portion in a width direction of the reading port and an amplitude corresponding to an end portion of an output waveform from the light receiving unit. The optical information reading device according to claim 1, wherein it is determined whether the optical information is appropriate. 6. A method according to claim 1, wherein said judging means judges whether the amount of received light is appropriate by comparing the minimum amplitude in the output waveform from said light receiving means with a predetermined judging amplitude. The optical information reading device according to claim 1. 7. Irradiation light from the light emitting means is radiated from the inside of the case to the object to be read outside through the reading opening of the case, so that reflected light from the object to be read is received inside the case through the reading opening. An optical information reading apparatus that forms an image on a unit and reads an image to be read by the light receiving unit, wherein an imaging state of the light receiving unit when a reading target for sampling is used is a width of the reading opening. Control value storage means for storing a light amount control value for the light emitting means in the case of an appropriate illuminance distribution in a direction corresponding to a plurality of sampling positions in which the distance from the reading port is sequentially changed; A distance sensor for measuring a distance from the object to the read object; and the control value storage means for storing the light amount control value corresponding to the distance to the read object measured by the distance sensor. From reading the optical information reading apparatus characterized by and a control means for performing light quantity control for said light emitting means based on the light amount control value. 8. The optical information reading apparatus according to claim 7, wherein the light quantity control value stored in the control value storage means is a control value of energy supplied to the light emitting means. 9. The light amount control value stored in the control value storage means is a control value of a light emission time of the light emitting means in a time zone in which the light receiving means can receive light. The optical information reading device according to claim 7, wherein: 10. An exposure time control for said light receiving means when said imaging value of said light receiving means is realized with an appropriate amount of received light when said reading object for sampling is used. The control unit also reads the exposure time control value corresponding to the measured distance to the read object from the control value storage unit, and stores the exposure time control value. 10. The optical information reading apparatus according to claim 7, wherein an exposure time control for the light receiving unit is performed based on a time control value. 11. An exposure time of said light receiving means is limited by a shutter, and said exposure time control value stored in said control value storage means is a control value of a time for opening said shutter. The optical information reading device according to claim 10, wherein 12. Irradiation light from the light emitting means is radiated from the inside of the case to a reading object outside the case through a reading port of the case, whereby reflected light from the reading object is received inside the case through the reading port. An optical information reading device that forms an image on a unit and reads an image to be read by the light receiving unit, wherein the amplification unit amplifies an output waveform of the light receiving unit at a predetermined amplification factor; The light amount control value for the light emitting unit when the image forming state of the light receiving unit is an appropriate illuminance distribution in the width direction of the reading port when using the light receiving unit. The exposure time control value for the light receiving means in the case where it is realized in, and the amplification factor in the case where the amplified output from the amplifying means is realized at an appropriate level. A control value storage unit storing a set of control values corresponding to a plurality of sampling states in which the ambient illuminance is sequentially changed; and a control value for one set is read from the control value storage unit, based on the read light amount control value. The light amount control is performed on the light emitting unit, the exposure time control is performed on the light receiving unit based on the read exposure time control value, and the amplifying unit is controlled to have the read amplification factor. An optical information reading apparatus comprising: a control unit that reads out another set of control values and executes the same control when an image cannot be read normally. 13. The optical information reading apparatus according to claim 12, wherein the light quantity control value stored in the control value storage means is a control value of energy supplied to the light emitting means. 14. The light amount control value stored in the control value storage means is a control value of a light emission time of the light emitting means in a time zone in which the light receiving means is capable of receiving light. The optical information reading device according to claim 12, wherein: 15. An exposure time of the light receiving means is limited by a shutter, and the exposure time control value stored in the control value storage means is a control value of a time for opening the shutter. The optical information reading device according to claim 14, wherein: 16. A light source according to claim 1, wherein said light emitting means is a point light source in which three or more light emitting diodes are arranged.
16. The optical information reading device according to any one of 15. 17. The optical information reading apparatus according to claim 1, wherein the object to be read is a barcode.