JP2001067432A - Optical information reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize an irradiation with read light enabling a proper read and an irradiation with guide light capable of displaying a proper guide function. SOLUTION: A bar code reader uses a light emitting diode 26 which is an incoherent light emitting element as a light source for read light and also uses a laser diode 30 which is a laser light emitting element as a light source for guide light showing a readable range. The light emitting diode 26 is used as the light source for read light, so no noise is generated when laser light is used as the read light. The laser diode 30 is used as the guide light source, so the directivity is relatively high and even when a bar code, etc., entered into a read object placed at a distance is read, the guide light showing the readable range is easily viewed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information reading apparatus for reading optical information from a reading object on which optical information such as a bar code is written, and more particularly to an optical apparatus capable of reading a bar code at a position distant from a reading port. The present invention relates to an information reading device.

[0002]

2. Description of the Related Art For example, a bar code attached to a product or the like is irradiated with reading light using a light emitting element such as a light emitting diode (LED) as a light source, and the reflected light is coupled to an optical sensor in which light receiving elements are arranged. 2. Description of the Related Art A bar code reader that reads an image of a bar code by imaging the bar code is known. Usually, such a bar code reader irradiates a bar code with a reading light in a state where a reading port provided in a case of the bar code reading device is almost in contact with the bar code, and the light reflected from the bar code is emitted. Is guided from the same reading port into the case of the bar code reader, and forms an image on the optical sensor.

[0003] In such a barcode reader, the barcode reader must be brought to a bar-coded product, and there is a problem that the reading operation is troublesome. In order to solve this problem, not only the bar code existing near the reading opening of the bar code reading device but also several tens cm from the vicinity of the reading opening.
(For example, 30 to 50 cm)
A so-called large-depth barcode reader that can read barcodes efficiently by forming an image on the light receiving means and reading the barcode without performing an operation of bringing the barcode reader closer to the product every time reading is considered. When reading a bar code located at such a distance, it is considered to irradiate guide light indicating a readable range.

Conventionally, LEDs have been used as light sources for reading light and guide light. However, in this case, there is a problem that the LED light, which has high illuminance around, becomes invisible, and does not function as guide light. One of the causes is that the directivity is low when an LED is used. Therefore, it is conceivable to use a laser beam having high directivity (see, for example, JP-A-62-6117).
In this case, even if the surrounding illuminance is high, the guide light by the laser light can be easily seen.

[0005]

However, the technique described in this publication has the following problems because the reading light and the guide light are realized by laser light. That is, laser light causes interference because of high coherence. When the laser light scatters on the rough surface, a random pattern (bright and dark) is formed by interference. This is called speckle, and this speckle causes a rough surface (for example, a surface on which a bar code exists) on the optical sensor.
Irrespective of the black and white, light and dark due to interference are converted into electrical signals, resulting in noise. For this reason, when laser light is used as the reading light,
The S / N ratio of the electric signal corresponding to the bar code output from the optical sensor decreases, and the reading performance decreases.

In order to prevent such inconvenience, a configuration may be adopted assuming that a non-coherent light emitting element such as an LED which does not generate such noise is used as a light source of reading light. Therefore, the present invention uses a non-coherent light emitting element as a light source of the reading light, and a laser light emitting element such as a laser diode as a light source of the guide light, thereby realizing appropriate reading and realizing the effective light as the guide light. It is an object of the present invention to provide an optical information reading device capable of ensuring the performance.

[0007]

According to the first aspect of the present invention, there is provided an optical information reading apparatus comprising: a non-coherent light emitting element as a light source; Is irradiated with reading light. Then, when the reflected light from the object to be read is imaged on the light receiving surface by the imaging optical system, the optical sensor converts the intensity of the reflected light into an electric signal and outputs the electric signal. on the other hand,
A guide light irradiating unit using a laser light emitting element as a light source irradiates a target to be read with guide light indicating a readable range of the apparatus.

[0008] Here, the non-coherent light emitting element is, for example, an LED or the like, and has the purpose of excluding a coherent laser light emitting element. Examples of the laser light emitting element include a laser diode and a gas laser.
On the other hand, examples of the optical sensor include a CCD image sensor and a CMOS image sensor.

As the guide light, for example, two laser light emitting elements may be used to irradiate both ends of the readable range in the form of spots, respectively. By irradiating the irradiation light from the lens with a guide light irradiation lens in a line shape in the longitudinal direction of the light receiving surface to generate the guide light, an appropriate guide light can be obtained with one laser light emitting element.

As described above, in the optical information reading apparatus of the present invention, since a non-coherent light emitting element such as an LED is used as a light source of reading light, noise when the above-described laser light is used as reading light is reduced. Does not occur. On the other hand, since a laser light emitting element such as a laser diode is used as the light source of the guide light, the directivity is relatively high, and it can be read even when reading optical information written on a distant reading target. It becomes easy to visually recognize the guide light indicating the appropriate range. That is, when an LED is used as a guide light source as in the conventional case, the size of the light source has a finite value (for example, several hundred μm), and when an image is formed by an optical system such as a lens or a mirror, the optical system The light source is magnified by the magnification, and cannot be condensed below a certain size. On the other hand, when a laser light emitting element is used as the light source, the size of the light source is theoretically infinitely small (point light source), so that it is small regardless of the magnification of the imaging optical system (although it is affected by diffraction). It can be focused on a spot. Also, even when the lens is expanded in a line shape by the guide light irradiation lens, a thin and clear line can be realized. Therefore, in the case of the guide light by the LED, the guide light that the surrounding illuminance is high was not seen. However, by using the laser light emitting element as the light source, such inconvenience is eliminated, and it is possible to suitably function as the guide light. it can.

By the way, if the optical axis (sensor optical axis) when the reflected light from the object to be read forms an image on the light receiving surface of the optical sensor coincides with the optical axis of the guide light, the range indicated by the guide light Can completely match the readable range. However, in practice, it is necessary to prevent the reflected light from the object to be read from blocking the optical path until it forms an image on the light receiving surface of the optical sensor. Therefore, it is important how to reduce the deviation.

In view of this, it is conceivable to employ the guide light irradiating means described in claim 4. That is, the laser light emitting elements are arranged so as not to block the optical path until the reflected light from the reading target forms an image on the light receiving surface of the optical sensor. At the same time, a guide light path changing member for changing the light path of the irradiation light from the laser light emitting element to be the guide light is provided so that the optical axis of the optical sensor and the optical axis of the guide light are as close as possible.

When such a guide light path changing member is not used, the laser light emitting element must be arranged so as not to block the optical axis of the sensor. Depending on the physical size of the constituent members, there may be cases where the two optical axes cannot be brought close enough. Therefore, by eliminating the influence of the physical size of the laser light emitting element using the optical path changing member for guide light, both optical axes can be made as close as possible.

It is conceivable that the guide light path changing member is a plane mirror. When a non-planar mirror (for example, a concave mirror or an aspherical miter) is used, it is preferable to use a plane mirror because the generated guide light is curved and does not become straight.

Further, in the case of the configuration including the guide light irradiating lens and the guide light optical path changing member as described above, at least the guide light irradiating lens and the guide light optical path changing member are provided. One of them may be configured to be movable. By moving at least one of these members, the intersection angle between the two optical axes can be adjusted. Although there is a desired value for the intersection angle between the two optical axes, it is necessary to create and assemble components with high precision in order to realize the desired value. Therefore, by providing a mechanism that can be adjusted later, it is not necessary to strictly request the production and assembly of highly accurate parts.

Although the adjusting function can be exerted by moving either one of the members individually, there is a case where it is desired to move both members while maintaining the relationship between the two members. Therefore,
As described in claim 7, the guide light irradiation lens and the guide light optical path changing member are assembled on the same holding member,
By operating the holding member, both may be configured to be integrally movable in the direction of the optical axis of the optical sensor.

On the other hand, regarding the arrangement of the optical axis of the guide light,
According to an eighth aspect of the present invention, it is conceivable to arrange the optical sensor so that the optical axis of the guide light exists on a plane including the optical axis of the optical sensor and in the lateral direction of the light receiving surface. The guide light is emitted in the width direction of the readable range. In the case of the above-described linear guide light, the width of the readable range is indicated by the length of the line. In this case, if the two optical axes are not arranged in the same plane as the short side direction of the light receiving surface, the guide light is changed when the relationship between the range indicated by the guide light and the readable range changes depending on the reading position. It becomes inconvenient when the user searches for a readable range by relying on. In other words, for example, if the range indicated by the guide light is set to be equal to or smaller than the readable range, even if the two optical axes are shifted, even if the specific positional relationship is appropriate, At positions other than the above, there is a high possibility that one end of the range indicated by the guide light will be out of the readable range.

Therefore, if the optical axis of the optical sensor and the optical axis of the guide light are arranged on the same plane in the lateral direction of the light receiving surface,
Such disadvantages are eliminated. For example, considering a line-shaped guide light, even if both optical axes are shifted in the short direction of the light receiving surface, it is because the line pointing near the center of the readable range at a specific position is orthogonal to the longitudinal direction of the line. This is because they only move in the direction in which they do.

Further, if the range indicated by the guide light is equal to or smaller than the visual field of the optical sensor by a predetermined amount, reading cannot be performed even at the portion pointed to by the guide light. Can be prevented.
By the way, as an example to improve the effectiveness of the guide light,
It is conceivable that the guide light irradiation means is configured as shown in claim 10. That is, the irradiation light from the laser light emitting element is spread in a line shape, and guide light is generated near both ends of the line, which is brighter than the other range. With this configuration, since both ends of the guide light, that is, both ends of the readable range, can be accurately grasped, the user operates the optical information reading apparatus such that the optical information described in the reading target is positioned within both ends of the guide light. It is easy to operate because you only need to bring it.

Further, not at both ends of the guide light,
As shown in FIG. 1, guide light near the center of the line may be brighter than other ranges. In this case, since the center of the readable range can be accurately grasped, the user only needs to bring the optical information reading device so that the center of the guide light is positioned at the center of the optical information described in the reading target. Easier to remove.

As a matter of course, as in the twelfth aspect, guide light may be generated in which the vicinity of both ends and the center of the line is brighter than other ranges. And these claim 1
As described in Nos. 0 to 12, when realizing a guide light irradiating unit that makes a part of the guide light brighter than the others, it is conceivable to make it as in claim 13. That is, a guide light irradiating lens for generating guide light by spreading the irradiation light from the laser light emitting element in a line shape is used, and the guide light irradiating lens is used for a portion that is brighter than the other range in the guide light. Can be realized by making the degree of spread when the irradiation light from the laser light emitting element is spread linearly smaller than in other ranges. By doing so, the light flux becomes relatively dense in a portion where the degree of spread of the irradiation light is small, and becomes brighter than other portions. Alternatively, it is possible to reduce the illuminance by, for example, partially filtering, but in this case, the overall illuminance decreases,
It can be said that it is preferable to use the above-described guide light irradiation lens.

By the way, various shapes can be adopted as the overall shape of the optical information reading apparatus, but in the case of portability, that is, in the case of a so-called bend structure, the main parts are stored in the main body, and A reading port is provided at the tip of the neck extending obliquely downward. Therefore, in this case, it is necessary to change the optical path of the reflected light from the object to be read and to make it incident on the imaging optical system. Also, besides that,
The optical paths of the reading light and the guide light also need to be changed. On the premise of such a configuration, claim 14
As shown in (1), an optical path changing member for changing the optical path of the reflected light from the reading target and entering the image forming optical system is provided, and the optical path changing member also changes the optical paths of the reading light and the guide light. It is conceivable to configure so as to change it. In this case, since one optical path changing member can be used, it is effective to simplify the configuration.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. It is needless to say that the embodiments of the present invention are not limited to the following examples, and can take various forms as long as they belong to the technical scope of the present invention.

FIG. 1 is a schematic explanatory view showing an internal structure of a head portion of a bar code reader 1 as an embodiment, and FIG. 1A is a partially omitted view seen from above.
(B) is the figure seen from the side. FIG. 2 is a block diagram of the control system. Various components for reading (hereinafter, appropriately referred to as a “reading unit”) are disposed in a front portion of the case 12 provided in the barcode reading device 1, and an operator is provided in a rear portion of the case 12. A grip (not shown) for gripping with a hand is formed. A reading port 22 that is long in the left and right directions (in the direction perpendicular to the paper surface in FIG. 1B), that is, long in the width direction, is provided in the lower front part of the case 12. In addition, a dustproof plate (not shown) is disposed behind the reading port 22 to close the reading port 22. As a result, dust is transferred from the reading port 22 to the case 12.
Prevents intrusion into the inside. Further, the dustproof plate can pass at least the reading light and the guide light described below.

The reading unit corresponds to a "non-coherent light emitting element", and includes a light emitting diode (LED) 26 for irradiating reading light, a reading light irradiating lens 27, an LE
D light emission drive circuit 28 (see FIG. 2), laser diode 30 corresponding to “laser light emitting element”, laser diode light emission drive circuit 31 (see FIG. 2), and reflection mirror 32 corresponding to “optical path changing member” , An imaging lens 34,
A sensor mirror 35, an optical sensor 36 corresponding to an "optical sensor", a guide light irradiation lens 50 corresponding to a "guide light irradiation lens", and a laser corresponding to a "guide light path changing member" And a diode mirror 52. In this embodiment, an LED group composed of four LEDs 26 is arranged on both sides of the imaging lens 34, and a reading light irradiation lens 27 is provided corresponding to each LED group. .

Each of these elements is basically an optical holder 60
It is assembled on the basis of. For example, the optical sensor 36 is mounted on a main board 58 mounted on the optical holder 60. Also, as shown in FIG.
The guide light irradiation lens 50 and the laser diode mirror 52 are mounted on a sub-holder 54 corresponding to a “holding member”, and the sub-holder 54 itself is mounted on the optical holder 60 as shown in FIG. ing.
The sub holder 54 has a long hole 55 as shown in FIG.
And is screwed into the optical holder 60 by using the long hole 55, so that it can be moved back and forth by the length of the long hole 55. The front-back direction is the direction of the optical axis of the optical sensor 36 (sensor optical axis). Therefore, the guide light irradiation lens 50 and the laser diode mirror 52 assembled to the sub holder 54 can be integrally moved in the sensor optical axis direction.

The LED 26 is driven by the LED emission driving circuit 28.
Is emitted, the light reflected by the reflection mirror 32 passes through the dustproof plate, and the bar code 8 outside the case 12 is
Is irradiated. The light reflected by the bar code 8 enters the case 12 again from the dust-proof plate, is reflected by the reflection mirror 32, and is incident on an imaging lens 34 provided with a stop (not shown) on the front surface. Via 34,
Further, the light is reflected by the sensor mirror 35 and is imaged by the optical sensor 36. In the optical sensor 36, the light receiving elements are linearly arranged in one line, and an image of the bar code 8 is arranged on the light receiving element, and the arrangement direction of each bar (the length direction of the bar code 8) and the arrangement of the light receiving elements. The image is formed in the same direction. The optical sensor 36 receives the reflected light from the bar code 8 and outputs it to the data processing output unit as an electric signal indicating the intensity of the light. The configuration of this data processing output unit will be described later.

The image forming optical system including the reflecting mirror 32, the image forming lens 34, and the sensor mirror 35 has at least the position of the reading port 22 and the number 1 from the position of the reading port 22.
It is configured as a deep imaging system so that it can read the bar code 8 up to a position separated by 0 cm (for example, 30 to 50 cm).

Next, the configuration of the data processing output unit will be described. Main board 58 inside case 12 (see FIG. 1)
On the top, as shown in FIG.
2, a microcomputer 44, and an output circuit 46 to a main unit such as a register and a host computer. When the read data of the bar code 8 is input from the reading unit via the waveform shaping unit 40, the data processing output unit decodes (decodes) the data by the processing of the microcomputer 44 and outputs the information represented by the bar code 8. And the information is temporarily stored in the memory 42. Next, the information stored in the memory 42 is transmitted to the main unit by the output circuit 46 at a predetermined timing by wireless communication using light or radio waves or by wire.

A buzzer device 48 is provided at a position where the reading unit is housed and does not affect the optical path. When the microcomputer 44 succeeds in decoding the bar code 8, the buzzer device 48 sounds. Like that. Although not shown, a battery as a power supply is also housed in the case 12. The microcomputer 44 includes a CPU, a ROM, a RAM, an I / O, and the like, and executes necessary processing as the above-described data processing output unit.

Next, the guide light irradiation lens 50 will be described. The guide light irradiation lens 50 irradiates the laser light from the laser diode 30 to the laser diode mirror 52.
This is a lens for spreading the laser light reflected by the fan-like shape and irradiating the bar code 8 with linear guide light indicating the readable range. This guide light irradiation lens 50
Is a resin lens integrally formed of a transparent resin, and has an elongated shape in the left-right direction of the case 12, as shown in FIGS.

FIG. 4A shows a guide light irradiating lens 50 shaped so as to transfer the light intensity distribution of the laser diode 30 as a light source as guide light on the bar code 8 as it is. In other words, the linear guide light is emitted onto the bar code 8, but as illustrated in FIG.
The guide light has a light intensity distribution substantially equal to the intensity distribution of the laser diode on the line. In addition,
The line width in FIG. 5 indicates the degree of coarse density of the light beam, and the denser the light, the higher the light intensity.

On the other hand, the guide light irradiation lens 50 shown in FIGS. 4B to 4D can be obtained by changing a part of the shape of the guide light irradiation lens 50 shown in FIG.
The light intensity distribution of the guide light on the bar code 8 is changed. This will be specifically described. First, the guide light irradiation lens 50 shown in FIG. 4B realizes a distribution in which the end portions are brighter than other portions. In the case shown in FIG. 4A, the side on which the laser beam from the laser diode 30 is incident is formed in a concave shape. In FIG. It is formed in a convex shape as indicated by α. Note that the convex shape is not an essential requirement, and the curvature may be smaller (that is, the radius of curvature is larger) than that in FIG. By forming in this way, as illustrated in FIG. 6, the guide light for irradiating the end portion has a denser light flux than the guide light for irradiating other portions, and as a result, is brighter than the other portions.

The guide light irradiating lens 50 shown in FIG. 4 (c) realizes a distribution in which the central portion is made brighter than the other portions. It is formed in a convex shape as shown by β. FIG. 4 (b)
In this case, as in the case of FIG.
May be made smaller (that is, the radius of curvature is made larger) than that of the above. Thereby, as exemplified in FIG.
The guide light illuminating the central portion has a denser luminous flux than the guide light illuminating other portions, and as a result, is brighter than the other portions.

The guide light irradiating lens 50 shown in FIG. 4D realizes a distribution in which the end portion and the center portion are brighter than other portions, and is indicated by arrows α and β in the drawing. As described above, the portions that irradiate the ends and the center are formed in a convex shape. Of course, also in this case, the curvature may be smaller (that is, the radius of curvature is larger) than that of FIG. That is, it is the sum of the shapes of FIGS. 4B and 4C, and as illustrated in FIG. 8, the guide light for irradiating the end and the center is more than the guide light for irradiating the other parts. The denser luminous flux results in a brighter than other parts.

The guide light irradiating lens 50 having any shape shown in FIGS. 4A to 4D may be used.
If both ends and / or the center of the guide light are made brighter than other portions, there is an advantage that the readable range can be grasped by using the light as a mark. That is, if the user can accurately grasp both ends of the readable range, the user only needs to bring the barcode reader 1 so that the optical information described in the object to be read is located within both ends of the guide light. If the center of the readable range can be accurately grasped, the user can bring the barcode reader 1 so that the center of the guide light is located at the center of the optical information described in the reading target. After all operation becomes easy.

In any of the cases where the guide light irradiation lens 50 is used, as shown in FIG. 9, the range H1 indicated by the linear guide light formed by the lens 50 is optical. It is set to be shorter than the field of view of the target sensor 36, that is, the width H2 of the readable range by a predetermined amount. This is to prevent the inconvenience that reading cannot be performed even at the portion pointed by the guide light. The range H1 indicated by the guide light may be equal to the width H2 of the readable range. The "predetermined amount" to be shorter than the width H2 of the readable range may be set as appropriate. However, if the "predetermined amount" is too large, a portion that can be actually read but is not indicated as the guide light increases. preferable.

By the way, if the optical axis (sensor optical axis) when the reflected light from the bar code 8 forms an image on the light receiving surface of the optical sensor 36 coincides with the guide optical axis, the guide light indicates. The range can be made to exactly match the readable range. However, in practice, it is necessary to prevent the reflected light from the bar code 8 from blocking the optical path until it forms an image on the light receiving surface of the optical sensor 36, so that a deviation between both optical axes can be avoided. Absent. Therefore, it is important how to reduce the deviation.

Therefore, in the present embodiment, the deviation between the two optical axes is minimized by using the above-described laser diode mirror 52. That is, as shown in FIG. 6A, the laser diode 30 is arranged so as not to block the optical path until the reflected light from the bar code 8 forms an image on the light receiving surface of the optical sensor 36, and the sensor optical axis The optical path of the irradiation light from the laser diode 30 is reflected by the laser diode mirror 52 so that the laser light and the guide optical axis are brought as close as possible. When the laser diode mirror 52 is not used, as shown in FIG.
b must be disposed, and the physical size of the laser diode 30b prevents the sensor optical axis from coming close enough to the guide optical axis (when no mirror is used). Therefore, by using the laser diode mirror 52 to eliminate the influence of the physical size of the laser diode 30, the two optical axes can be made as close as possible.

The effect of bringing the two optical axes closer to each other will be briefly described. For example, consider a case where there is a rectangular readable range S as shown in FIG. 10B and linear guide light is emitted in the longitudinal direction of the readable range S. At the position where the sensor optical axis and the guide optical axis intersect, the linear guide light G1 is applied to the central portion in the lateral direction of the readable range S. If the position is farther than the position where both optical axes intersect, the linear guide light G2 is shifted upward in the short direction of the readable range S in FIG. If the position is closer than the position where
Speaking in (b), it is shifted downward in the short direction of the readable range S. If the sensor optical axis and the guide optical axis are brought as close as possible using the laser diode mirror 52, the degree of deviation shown in FIG. 10B is reduced, and the function as the guide light indicating the readable range S is exhibited. The range that can be expanded.

In this embodiment, a flat mirror is used as the laser diode mirror 52. However, when a non-planar mirror (for example, a concave mirror or an aspherical miter) is used, the generated guide light is curved. Have done
This is because it does not become a straight line. Further, as described with reference to FIG. 3, the guide light irradiation lens 50 and the laser diode mirror 52 are assembled to the sub holder 54, and the guide light is moved by moving the sub holder 54 in the sensor optical axis direction. The irradiation lens 50 and the laser diode mirror 52 can be integrally moved. With this movement, the intersection angle between the sensor optical axis and the guide optical axis can be adjusted. Although there is a desired value for the intersection angle between the two optical axes, it is necessary to create and assemble components with high precision in order to realize the desired value. Therefore, in the present embodiment, by providing a mechanism that can be adjusted later, it is not necessary to strictly require the production and assembly of highly accurate components.

In this embodiment, the guide light irradiating lens 50 and the laser diode mirror 52 are integrally moved, but they may be individually movable. By moving at least one of these members, the intersection angle between the two optical axes can be adjusted.

Further, in the present embodiment, the following contrivances have been made regarding the arrangement of the guide optical axis. That is, as can be seen from FIG. 1 and the like, the laser diode 30 and the guide light irradiation are performed such that the guide light optical axis exists on the plane in the short direction of the light receiving surface of the optical sensor 36, including the sensor optical axis. Lens 50 and a laser diode mirror 52 are arranged.

The effect of the arrangement of the guide light optical axes will be briefly described. As described in FIG. 6, the guide light is transmitted in the longitudinal direction (width direction) of the readable range S.
, And the length of this line indicates the width of the readable range S. In this case, as shown in FIG. 11 (a), unless the sensor optical axis and the guide optical axis are arranged in the same plane as the short side direction of the light receiving surface of the optical sensor 36, the optical sensor 36 is viewed in the longitudinal direction of the light receiving surface. If the relationship between the range indicated by the guide light and the readable range S changes depending on the reading position due to the deviation of both optical axes, the user can set the readable range S by relying on the guide light. It is inconvenient when searching. For example, if the range indicated by the guide light is set to be equal to the readable range S, the two optical axes are shifted, so that the guide light G11 is at a specific position as shown in FIGS. Even if the readable range S is properly indicated, as shown in FIGS. 11A, 11B and 11D, the guide light G12, G13
Is more likely to deviate from the readable range S.

Therefore, if the optical axis of the sensor and the optical axis of the guide are arranged on the same plane in the lateral direction of the light receiving surface of the optical sensor 36 as in the present embodiment, such inconvenience is eliminated. That is, as shown with reference to FIG. 10, even if both optical axes are shifted in the short direction of the light receiving surface, the line indicating the vicinity of the center of the readable range S at a specific position is the line of the line. This is because it only moves in the direction orthogonal to the longitudinal direction.

In this embodiment, since the so-called neck bending structure is employed as the overall shape of the bar code reading device 1, the light path of the reflected light from the bar code 8 is changed to be incident on the imaging lens 34. Need to be done. In addition, it is necessary to similarly change the optical path of the reading light emitted from the LED 26 and the guide light emitted from the laser diode 30. Therefore, one reflection mirror 32
Thus, the optical paths of these three lights are changed. This is effective for simplifying the configuration.

Further, in the bar code reader 1 of this embodiment, since the LED 26 which is a non-coherent light emitting element is used as a light source of the reading light, no noise is generated when the laser light is used as the reading light. . On the other hand, since the laser diode 30 which is a laser light emitting element is used as the light source of the guide light, the directivity is relatively high, and even when reading the barcode 8 described on the reading object at a distant place, It becomes easy to visually recognize the guide light indicating the readable range. That is, when an LED is used as a light source for guide light as in the related art, the size of the light source has a finite value (for example, several hundred μm), and when an image is formed by an optical system such as a lens or a mirror, The light source is magnified by the magnification, and cannot be condensed below a certain size. On the other hand, when the laser diode 30 is used as the light source, the size of the light source is theoretically infinitely small (point light source), so that it is small regardless of the magnification of the imaging optical system (although it is affected by diffraction). It can be focused on a spot. And even when it is expanded in a line shape by the guide light irradiation lens 50, a thin and clear line can be realized. Therefore, the conventional LE
In the case of the guide light by D, this guide light that the surrounding illuminance is high was invisible.
By using 0 as the light source, such inconveniences are eliminated, and the light source can function suitably as the guide light.

[Others] (1) In the above embodiment, the guide light irradiation lens 50 is used to make a part of the linear guide light brighter than the others.
With respect to a portion brighter than the other range in the guide light, it was realized by making the degree of spread when the irradiation light from the laser diode 30 is spread linearly smaller than the other range, Other techniques may be employed. For example, as shown in FIG. 12, it is also possible to realize by reducing the illuminance partially by applying a filter having different light transmittance depending on a part. In the case of FIG. 12, since the transmittance at the center is lower than that at the ends, the illuminance at the ends is relatively high. In FIG. 13, the illuminance may be partially reduced by using a diaphragm having a different light transmission area depending on the part. In the case of FIG. 13, the illuminance at the end is relatively high because the transmission area at the center is smaller than that at the end.
However, when a filter or an aperture is used as shown in FIGS. 12 and 13, the overall illuminance is reduced because the method is a method of partially suppressing light transmission. Therefore, it can be said that it is preferable to use the above-described guide light irradiation lens 50.

It should be noted that if we add to the guide light,
Not limited to the line shape, for example, both ends and the center portion or both of the readable range may be irradiated in a spot manner. (2) In the above embodiment, four LEDs arranged in one row
26 are arranged on the left and right sides of the case 12, respectively.
26 may be one as long as it has a sufficient amount of light for reading, and if necessary, five or more LEDs 26 may form one LED.
A group may be formed.

(3) In the above embodiment, the description has been given of the case where the present invention is realized as the barcode reading device 1. However, the present invention can be realized as a device for reading a two-dimensional code.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an internal structure of a head portion of a barcode reader as one embodiment.

FIG. 2 is a block diagram of a control system of the bar code reader.

FIG. 3 is an explanatory diagram showing a state in which a guide light irradiation lens and a laser diode mirror of the bar code reader are assembled to a sub holder.

FIG. 4 is a diagram illustrating the shape of a guide light irradiation lens as one embodiment.

FIG. 5 shows the transfer of the light intensity distribution of the light source as it is.
It is explanatory drawing which illustrates irradiation light by the lens of (a).

FIG. 6 (b) for realizing a distribution for brightening an end portion
It is explanatory drawing which illustrates irradiation light by the lens of FIG.

FIG. 7 is a diagram for realizing a distribution for brightening the central part.
It is explanatory drawing which illustrates irradiation light by the lens of (c).

FIG. 8 is an explanatory diagram exemplifying irradiation light by the lens in FIG. 4D realizing a distribution for brightening an end portion and a central portion.

FIG. 9 is an explanatory diagram showing the relationship between the range (H1) indicated by the linear guide light and the width (H2) of the readable range.

FIG. 10 is an explanatory diagram showing a comparison with a case where the effect of using the laser diode mirror of the embodiment is not used.

FIG. 11 is an explanatory diagram of an effect provided by arrangement of a guide light optical axis.

FIG. 12 is an explanatory diagram in the case where the intensity distribution of guide light is made variable using a filter.

FIG. 13 is an explanatory diagram in the case where the intensity distribution of the guide light is made variable using a stop.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bar code reader 8 ... Bar code 12 ... Case 22 ... Reading port 26 ... Light emitting diode (LED) 27 ... Reading light irradiation lens 28 ... LED light emission drive circuit 30 ... Laser diode (LD) 31 ... Laser diode light emission drive Circuit 32 ... Reflection mirror 34 ... Imaging lens 35 ... Sensor mirror 36 ... Optical sensor 40 ... Waveform shaping unit 42 ... Memory 44 ... Microcomputer 46 ... Output circuit 48 ... Buzzer device 50 ... Guide light irradiation lens 52 ... Laser Diode mirror 54 ... Sub holder 55 ... Elongated hole 58 ... Main board 60 ... Optical holder G1 to G3, G11 to G13 ... Guide light H1 ... Guide light irradiation range H2 ... Readable range width S ... Readable range

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Noro 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Hiroshi Hayami 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Denso Corporation F-term (reference) 5B072 CC24 DD01 LL12 LL13 MM00

Claims (14)

[Claims] 1. A reading light irradiating means for irradiating a reading target on which optical information is written with a non-coherent light emitting element as a light source and a laser light emitting element as a light source and a guide indicating a readable range of the apparatus. Guide light irradiating means for irradiating the reading target with light; and when reflected light from the reading target is imaged on a light receiving surface by an imaging optical system, the reflected light is converted into an electric signal and output. An optical information reading device, comprising: 2. The optical information reading device according to claim 1, wherein said non-coherent light emitting element is a light emitting diode, and said laser light emitting element is a laser diode. 3. The optical information reading device according to claim 1, wherein the guide light irradiating means spreads the irradiation light from the laser light emitting element in a line shape in a longitudinal direction of the light receiving surface to guide the guide light. An optical information reading device comprising a guide light irradiating lens for generating. 4. The optical information reading device according to claim 3, wherein the guide light irradiating means does not block an optical path until reflected light from the object to be read forms an image on a light receiving surface of the optical sensor. The laser light emitting element is arranged, and the optical path of the irradiation light from the laser light emitting element is changed to guide light so that the optical axis of the optical sensor and the optical axis of the guide light are as close as possible. An optical information reading device comprising a guide light optical path changing member. 5. The optical information reading device according to claim 4, wherein the guide light optical path changing member is a plane mirror. 6. The optical information reading device according to claim 4, wherein at least one of the guide light irradiating lens and the guide light optical path changing member is configured to be movable. Information reading device. 7. The optical information reading device according to claim 6, wherein the guide light irradiating lens and the guide light optical path changing member are assembled to the same holding member, and by operating the holding member, An optical information reading apparatus characterized in that both are movable. 8. The optical information reading device according to claim 1, further comprising an optical axis of said optical sensor, and an optical axis of said guide light on a plane in a lateral direction of said light receiving surface. An optical information reading device characterized by the presence of: 9. The optical information reading apparatus according to claim 1, wherein a range indicated by said guide light is equal to or smaller than a field of view of said optical sensor by a predetermined amount. Optical information reader. 10. The optical information reading device according to claim 1, wherein said guide light irradiating means spreads the irradiation light from said laser light emitting element in a line shape, and the other ends near the both ends of the line are other than the above. An optical information reading device that generates guide light that is brighter than the range. 11. The optical information reading apparatus according to claim 1, wherein said guide light irradiating means expands the irradiation light from said laser light emitting element in a line shape, and a portion near the center of the line is other than the above. An optical information reading device that generates guide light that is brighter than the range. 12. The optical information reading device according to claim 1, wherein said guide light irradiating means expands the irradiation light from said laser light emitting element in a line shape, and near both ends and a center of the line. An optical information reading apparatus that generates a guide light that is brighter than the other range. 13. The optical information reading device according to claim 10, wherein said guide light irradiating means expands the irradiation light from said laser light emitting element in a line shape to generate guide light. A light irradiation lens is provided, and the guide light irradiation lens, for a portion brighter than the other range in the guide light, adjusts the degree of spreading when the irradiation light from the laser light emitting element is spread linearly. An optical information reading device having a shape smaller than other ranges. 14. The optical information reading apparatus according to claim 1, further comprising an optical path changing member for changing an optical path of the reflected light from the object to be read and causing the reflected light to enter the imaging optical system. And an optical path changing member configured to change the optical paths of the reading light and the guide light.