JP2009076016A - Optical information reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical information reader capable of suppressing the increase of a manufacturing cost by identifying an optical information reading range without using an exclusive device for irradiating marker light. <P>SOLUTION: The optical path R side ends of first and second lighting lenses 20, 30 include first and second refracting parts 22, 32 refracting a part of light emitted from first and second light sources 50, 51, to travel along the boundaries R1, R2 of an optical path R located on the side of the first and second lighting lenses 20, 30. Consequently, since both ends of a reading range E of a bar code C1 are brighter in illuminance than a portion other than both ends, the reading range E can be identified without an exclusive marker light irradiation device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical information reading apparatus that reads optical information represented by a one-dimensional code such as a bar code or a two-dimensional code such as a QR code.

  Conventionally, as this type of optical information reading apparatus, one described in Japanese Patent Application Laid-Open No. 2005-85214 (Patent Document 1) is known. This comprises a marker light irradiating means for irradiating a marker light for indicating a reading range for optical information and a light projecting lens arranged in front of the marker light irradiating marker light composed of spot light. It is supposed to be.

Japanese Patent Laying-Open No. 2005-85214 (13th paragraph, FIG. 4)

  However, the conventional device requires a dedicated device for irradiating the marker light, which causes an increase in manufacturing cost of the optical information reading device.

  The present invention has been made in order to solve the above-described problems, and enables manufacturing cost to be identified by enabling the optical information reading range to be identified without using a dedicated device for irradiating marker light. It is an object of the present invention to realize an optical information reading apparatus that can suppress the rise.

  In order to achieve the above object, according to the first aspect of the present invention, in the first aspect of the present invention, an imaging lens (40) for imaging the reflected light reflected by the recording surface on which the optical information (C1) is recorded; First and second illumination lenses (20, 30) arranged with the optical path (R1, R2) of the imaging lens interposed therebetween, and a first light source for emitting light to the first illumination lens (20) (50, 50) and a second light source (51, 51) for emitting light to the second illumination lens (30), wherein the first illumination lens is from the first light source. The emitted light (L1) is diffused to illuminate the optical information, and the second illumination lens diffuses the light (L2) emitted from the second light source to illuminate the optical information. An optical information reading device (10) configured as described above, wherein the first illumination lens That is, at the end on the optical path side, a part of the light emitted from the first light source within the range of the emission angle of the first light source is a boundary of the optical path located on the first illumination lens side. A first refracting portion (22) that refracts so as to travel along the optical path is provided, and an end portion on the optical path side of the second illumination lens is within an emission angle range of the second light source. A second refracting portion (32) is provided that refracts part of the light emitted from the second light source so as to travel along the boundary of the optical path located on the second illumination lens side. The technical means is used.

  According to a second aspect of the present invention, in the optical information reading device (10) according to the first aspect, an emission angle (β) of light emitted from the first and second refracting portions (22, 32) is The technical means that each of them is ½ of the angle of view (α) of the imaging lens is used.

  According to a third aspect of the present invention, in the optical information reading device (10) according to the first or second aspect, between the first light source (50) and the first refracting portion (29). Is provided with a first guide member (27) for guiding a part of the light emitted from the first light source to the first refracting portion, and the second light source (51) and the first light source A technique in which a second guide member (37) for guiding a part of light emitted from the second light source to the second refracting part is provided between the second refracting part (39) and the second refracting part (39). Use appropriate means.

  In addition, the code | symbol in the said parenthesis respond | corresponds with the code | symbol described in embodiment of the invention mentioned later.

(Operation of the Invention of Claim 1)
The light emitted from the first light source is diffused by the first illumination lens to illuminate the reading range of the optical information, and the light emitted from the second light source is diffused by the second illumination lens and optically Illuminates the reading range of information.
In addition, a part of the light emitted from the first light source within the range of the emission angle of the first light source is a first refraction provided at the end of the first illumination lens on the optical path side of the imaging lens. The light is refracted at the part and travels along the boundary of the optical path located on the first illumination lens side. Then, the light traveling along the boundary is irradiated to the end of the reading range located on the first illumination lens side. As a result, the end of the reading range located on the first illumination lens side is irradiated with the light refracted by the first refracting unit in addition to the light diffused and irradiated by the first illumination lens. Therefore, the illuminance at the end of the reading range located on the first illumination lens side is higher than the illuminance at the portion other than the end. That is, since the illuminance at the end of the reading range located on the first illumination lens side becomes brighter than the portion other than the end, the position of the end can be identified.

  In addition, a part of the light emitted from the second light source within the range of the emission angle of the second light source is a second refraction provided at the end of the second illumination lens on the optical path side of the imaging lens. The light is refracted in the part and travels along the boundary of the optical path located on the second illumination lens side. Then, the light traveling along the boundary is irradiated to the end of the reading range located on the second illumination lens side. As a result, the end of the reading range located on the second illumination lens side is irradiated with the light refracted by the second refracting unit in addition to the light diffused and irradiated by the second illumination lens. Therefore, the illuminance at the end of the reading range located on the second illumination lens side is higher than the illuminance at the portion other than the end. That is, since the illuminance at the end of the reading range located on the second illumination lens side becomes brighter than the portion other than the end, the position of the end can be identified.

(Effect of the invention according to claim 1)
Since both end portions of the optical information reading range can be illuminated brighter than portions other than the both end portions, the reading range can be identified.
Therefore, since the reading range of the optical information can be identified without using a dedicated device for irradiating the marker light, an increase in manufacturing cost of the optical information reading device can be suppressed.

(Operation of the Invention of Claim 2)
The first and second illumination lenses are arranged with the optical path of the imaging lens interposed therebetween, and the emission angles of the light emitted from the first and second refracting parts are respectively the same as the angle of view of the imaging lens. 1/2.
For this reason, the light emitted from the first and second refracting sections travels along the boundary of the optical path of the imaging lens, and is irradiated to the end of the reading range.

(Effect of the invention according to claim 2)
By designing the first and second refracting portions so that the emission angle of the light emitted from the first and second refracting portions is ½ of the angle of view of the imaging lens, respectively. The light emitted from the second refracting portion can be irradiated to the end of the reading range, respectively, and the illumination at both ends of the reading range can be brightened.

(Operation of the Invention of Claim 3)
Part of the light emitted from the first light source is guided to the first refracting portion by the first guide member, refracted by the first refracting portion, and irradiated to one end of the reading range. A part of the light emitted from the second light source is guided to the second refracting portion by the second guide member, refracted by the second refracting portion, and irradiated to the other end of the reading range. .

(Effect of the invention according to claim 3)
Since part of the light emitted from the first and second light sources is guided to the corresponding refracting part by the first and second guide members, respectively, part of the light emitted from the light source is efficiently supplied to the refracting part. I can guide you.
Accordingly, both ends of the optical information reading range can be illuminated more brightly, so that the readability of the reading range can be improved.

<First Embodiment>
Embodiments according to the present invention will be described with reference to the drawings.
In the following embodiments, a barcode reader that reads a barcode as optical information will be described as a representative example of the optical information reader according to the present invention. The bar code means a one-dimensional code such as EAN / UPC, interleaved 2 of 5, coder bar, code 39/128, standard 2 of 5, RSS.

[Main configuration]
The main configuration of the barcode reader according to this embodiment will be described with reference to the drawings. FIG. 1 is an explanatory view showing a partial internal structure of the barcode reader according to this embodiment, and FIG. 2 is a plan view showing a partial internal structure of the barcode reader shown in FIG.

  The barcode reader 10 is a gun type and includes a housing 11 and a grip 12 attached to the lower portion of the housing 11. The grip 12 is formed in a size and shape that can be grasped by a person with one hand, and a trigger switch 13 is provided on the front surface of the grip 12 for instructing the start of barcode reading. The trigger switch 13 is disposed at a position where an operation of pulling with the index finger mainly of the hand holding the grip 12 can be performed. When the trigger switch 13 is pulled, a reading start switch (not shown) disposed inside the grip 12 is turned on, and barcode reading is started.

  A reading port 11 a is formed in the front surface of the housing 11. Illumination light for illuminating the barcode is emitted from the reading port 11a, and reflected light reflected by the recording surface of the barcode is further incident. A camera module 15 and a circuit board 14 are provided inside the housing 11.

  As shown in FIG. 2, the camera module 15 includes a first light source 50 and a second light source 51 for illuminating the recording surface of the barcode C1 (FIG. 2), and light emitted from the first light source 50. And the first illumination lens 20 for illuminating the recording surface of the barcode C1 and the first illumination lens 20 for diffusing the light emitted from the second light source 51 to illuminate the recording surface of the barcode C1. Two illumination lenses 30 and an imaging lens 40 are provided.

  Further, as shown in FIG. 1, the camera module 15 is provided with an optical sensor 60 disposed behind the imaging lens 40. The imaging lens 40 images the reflected light reflected by the recording surface of the barcode C1 on the light receiving portion of the optical sensor 60. The optical sensor 60 electrically detects an image formed on the light receiving unit as a one-dimensional or two-dimensional captured image. The optical sensor 60 is, for example, a CCD image sensor in which CCDs (Charge Coupled Devices) are arranged in two dimensions (vertical and horizontal), or a C-MOS (Complementary Metal Oxide Semiconductor) in two dimensions (vertical and horizontal). And a two-dimensional image sensor such as a C-MOS image sensor.

  Although not shown, an A / D conversion circuit that converts an analog signal output from the optical sensor 60 into a binary signal corresponding to light and dark is output from the A / D conversion circuit to the circuit board 14. A circuit or the like that counts the binarized signal to calculate a light / dark width value and reads barcode information based on the sequence of the calculated width value is mounted.

As shown in FIG. 2, the first illumination lens 20 and the second illumination lens 30 are arranged with the optical path R of the imaging lens 40 therebetween. The first illumination lens 20 is disposed outside the left boundary R1 of the optical path R, and the second illumination lens 30 is disposed outside the right boundary R2 of the optical path R.
The first light source 50 is disposed behind the first illumination lens 20, and the second light source 51 is disposed behind the second illumination lens 30. In this embodiment, each of the first and second light sources is composed of a set of two LEDs, and the arrangement direction of each LED is perpendicular to the optical axis H1 of the imaging lens 40. . In addition, an LED that emits one of the emission colors such as white, red, and blue is selected and used. In this embodiment, the red LED that emits red light is used as the first and second light sources 50 and 51. Use.

[Structure of illumination lens]
Here, the structure of the 1st illumination lens 20 and the 2nd illumination lens 30 is demonstrated with reference to FIG. 3A and 3B are explanatory views showing the structure of the first illumination lens, in which FIG. 3A is a plan view of the first illumination lens viewed from above, FIG. 3B is a left side view of FIG. FIG. 4 is a right side view of (a).
Since the first and second illumination lenses have the same shape, the first illumination lens will be described as a representative here.

  The first illumination lens 20 uses a lenticular plate, and in this embodiment, is formed in a horizontally long plate shape. In the first illumination lens 20, the front surface 23 is formed as a convex lens, and the rear surface 21 is formed with a lenticular lens for making the illuminance distribution of the illumination light emitted from the front surface 23 uniform. In addition, since the unevenness | corrugation which comprises a lenticular lens is minute, it is not illustrated.

The right side surface 25 of the first illumination lens 20, that is, the end of the imaging lens 40 on the optical path R side, includes the illumination light L 1 emitted from the first light source 50 within the range of the emission angle of the first light source 50. A first refracting portion 22 is formed that refracts a part so as to proceed along the boundary R1 of the optical path R located on the first illumination lens 20 side. In this embodiment, a prism is formed by chamfering the upper and lower corners on the optical path R side of the first illumination lens 20, and the prism is used as the first refracting portion 22.
Similarly, as shown in FIG. 2, the second illumination lens 30 also forms a prism by chamfering the upper and lower corners on the optical path R side, and the prism is used as the second refracting portion 32. The first and second illumination lenses 20 and 30 are formed in a line-symmetric shape with the optical axis H1 of the imaging lens 40 as the center.

FIG. 4 is an explanatory diagram showing the relationship between the angle of view of the imaging lens 40 and the exit angle of illumination light that is refracted by the first refracting unit 22 and exits from the front surface 23 of the first illumination lens 20.
If the angle of view of the imaging lens 40 is α and the exit angle of the illumination light refracted by the first refracting unit 22 and emitted from the front surface 23 of the first illumination lens 20 is β, the exit angle β is equal to the angle of view α. (1/2) is set.
That is, the illumination light emitted from the first light source 50 and refracted by entering the first refracting portion 22 of the first illumination lens 20 is further refracted at the front surface 23 and emitted at the emission angle β, and the optical path Proceed along the boundary R1 on the left side of R.

  FIG. 5 is an explanatory diagram showing an incident angle and a refraction angle in the prism. When the incident angle is i, the refraction angle is r, the absolute refractive index of the material on the incident light side is ni, and the absolute refractive index of the material on the refracted light side is nr, the refraction angle with respect to the incident angle in the prism is ni · sin (i ) = Nr · sin (r). That is, the first refracting portion 22 is formed so that the emission angle β of the illumination light that passes through the first refracting portion 22 using the prism and is emitted from the front surface 23 is (½) of the angle of view α. The material to be selected is selected, and the angle of the cut surface (surface indicated by reference numeral 22) of the prism is calculated. The same applies to the second illumination lens 30. In addition, the first and second illumination lenses can be made of synthetic resin or glass, respectively, and the first and second refracting parts can be made of the same material. The refractive part may be manufactured separately from the illumination lens and joined to the illumination lens by a known joining means (for example, an adhesive). Furthermore, the refractive part may be formed of a material different from that of the illumination lens.

[Function of illumination lens]
A part of the illumination light L1 emitted from the first light source 50 enters the rear surface 21 of the first illumination lens 20 and is diffused by the lenticular lens formed on the rear surface 21. The diffused light is changed to illumination light having a height in the vertical direction, that is, the height of the reading range of the barcode C1, by the convex lens formed on the front surface 23, and mainly on the left side of the reading range of the barcode C1. Irradiated.
In addition, a part of the illumination light L1 emitted from the first light source 50 is incident on the first refracting portion 22 formed at the right end of the first illuminating lens 20, and forms a first refracting portion 22. And exits from the front surface 23 at an exit angle β.

  Then, the emitted light travels along the left boundary R1 of the optical path R of the imaging lens 40, and becomes the guide light G1 and irradiates the left end of the reading range of the barcode C1. As a result, the left end of the reading range E of the barcode C1 is also irradiated with the illumination light refracted by the first refracting unit 22 in addition to the illumination light diffused and irradiated by the first illumination lens 20. Therefore, the illuminance at the left end portion of the reading range E of the barcode C1 is higher than the illuminance at portions other than both end portions.

Part of the illumination light L <b> 2 emitted from the second light source 51 is incident from the rear surface 31 of the second illumination lens 30 and is diffused by the lenticular lens formed on the rear surface 31. The diffused light is changed to illumination light having a height in the vertical direction, that is, the height of the reading range of the barcode C1, by the convex lens formed on the front surface 33, and mainly on the right side of the reading range of the barcode C1. Irradiated.
In addition, a part of the illumination light L2 emitted from the second light source 51 is incident on the second refracting portion 32 formed at the left end of the second illumination lens 20, and forms a second refracting portion 32. And exits from the front surface 33 at an exit angle β.

  Then, the emitted light travels along the right boundary R2 of the optical path R of the imaging lens 40, and becomes the guide light G2, and irradiates the right end of the reading range of the barcode C1. Accordingly, the right end of the reading range E of the barcode C1 is irradiated with the illumination light refracted by the second refracting unit 32 in addition to the illumination light diffused and irradiated by the second illumination lens 30. Therefore, the illuminance at the right end of the reading range E of the barcode C1 is higher than the illuminance at the portion other than both ends.

[Effect of the first embodiment]
(1) As described above, if the barcode reader 10 of the first embodiment is used, the illuminance at both ends of the reading range E of the barcode C1 can be made brighter than the portions other than both ends. Range E can be identified.
Therefore, since the reading range of the optical information can be identified without using a dedicated device for irradiating the marker light, an increase in manufacturing cost of the optical information reading device can be suppressed.

(2) The first and second refracting portions are designed so that the emission angle β of the light emitted from the first and second refracting portions is ½ of the angle of view α of the imaging lens 40, respectively. Thus, the light emitted from the first and second refracting portions can be irradiated to the end portions of the reading range E, and the illumination at both ends of the reading range E can be brightened.

<Example of change>
Next, a modified example of the first embodiment will be described with reference to FIGS. 6 is a plan view corresponding to FIG. 2, and FIG. 7 is a plan view corresponding to FIG.
This modification is characterized in that a prism is formed in front of the first and second illumination lenses. Since this modified example has the same configuration as the barcode reader 10 of the first embodiment except for the structure of each illumination lens, the description of the same configuration is omitted.

  As shown in FIG. 7, at the right side surface 25 of the first illumination lens 20, that is, at the end of the imaging lens 40 on the optical path R side, the first light source 50 within the range of the emission angle of the first light source 50. A first refracting portion 26 is formed that refracts a part of the illumination light L1 emitted from the light so as to travel along the boundary R1 of the optical path R located on the first illumination lens 20 side. In this embodiment, a prism is formed by chamfering the upper and lower corners on the optical path R side of the first illumination lens 20, and the prism is used as the first refracting portion 26.

Similarly, as shown in FIG. 6, the second illumination lens 30 also forms a prism by chamfering the front upper and lower corners on the optical path R side, and the prism is used as the second refracting portion 36.
Further, the emission angle β of the illumination light emitted from the first refracting unit 26 and the second refracting unit 36 is (1/2) of the field angle α of the imaging lens. The second illumination lens 30 is formed in a line-symmetric shape with the first illumination lens 20 with the optical axis H1 of the imaging lens 40 as the center.
As described above, the barcode reader according to this modified example is the same as the barcode reader of the first embodiment except that the formation positions of the first and second refracting portions in the first and second illumination lenses are different. Since it has a structure and performs the same operation, the same effect as the first embodiment can be obtained.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIGS. 8 is an explanatory diagram corresponding to FIG. 2, and FIG. 9 is an explanatory diagram corresponding to FIG.
This embodiment is characterized in that a guide member for guiding the illumination light emitted from the first and second illumination lenses to the corresponding refracting portion is provided. In addition, since this embodiment is the same structure as the barcode reader 10 of 1st Embodiment except having provided the guide member, description is abbreviate | omitted about the same structure.

  As shown in FIG. 8, between the first light source 50 and the first refracting unit 29, a first part of the illumination light emitted from the first light source 50 is guided to the first refracting unit 29. A guide member 27 is provided, and between the second light source 51 and the second refracting portion 39, part of the illumination light emitted from the second light source 51 is guided to the second refracting portion 39. A second guide member 37 is provided. The guide members 27 and 37 can be formed of the same material as the illumination lenses 20 and 30 or a different material.

  As shown in FIG. 9, the first guide member 27 is formed in a wedge shape and is formed integrally with the first refracting portion 29. Of the first guide member 27, an illumination light capturing portion 28 for capturing a part of the illumination light emitted from the first light source 50 is formed at the thinnest rear end. The illumination light capturing unit 28 is disposed within the emission angle range of the first light source 50 in order to capture a part of the illumination light emitted from the first light source 50.

  In addition, the distance between the side walls 27a and 27b facing each other in the first guide member 27, the extent of the distance between the side walls between the illumination light capturing part 28 and the first refracting part 29, and the first guide. The arrangement angle of the member 27 with respect to the first light source 50 is such that the illumination light taken in from the illumination light take-in portion 28 is totally reflected on the opposite side walls 27a and 27b, and the amount of light leaking outward from the side walls is reduced. Designed to be That is, each guide member 27, 37 plays a role like a waveguide.

  A part of the illumination light emitted from the first light source 50 is taken into the illumination light take-in portion 28 of the first guide member 27, and a part of the taken illumination light is taken as the first guide member. 27 is incident on the first refracting portion 29 while being totally reflected by the opposing side walls 27a and 27b. That is, a part of the illumination light taken into the illumination light take-in portion 28 is efficiently guided to the first refracting portion 29 without almost leaking from the side wall of the first guide member 27.

  The illumination light incident on the first refracting portion 29 exits the first refracting portion 29 at an emission angle β that is (½) of the field angle α of the imaging lens 40, and the optical path of the imaging lens 40. Proceeding along the boundary R1 of R, the left end portion of the reading range E of the barcode C1 is illuminated with an illuminance brighter than the portions other than both end portions. The second guide member 37 is formed in a line-symmetric shape with the first guide member 27 with the optical axis H1 of the imaging lens 40 as the center.

[Effects of Second Embodiment]
(1) As described above, when the barcode reader according to the second embodiment is used, part of the illumination light emitted from the first and second light sources 50 and 51 is the first and second guides, respectively. Since the members 27 and 37 are guided to the corresponding refracting portions 29 and 39, a part of the illumination light emitted from the light source can be efficiently guided to the refracting portions 29 and 39.
Therefore, both ends of the reading range E of the barcode C1 can be illuminated more brightly, so that the distinguishability of the reading range E can be improved.

(2) Moreover, since it has the same configuration as the barcode reader of the first embodiment except that the first and second guide members 27 and 37 are provided, the same effect as the first embodiment can be obtained. Can do.

<Other embodiments>
(1) In each of the above-described embodiments and modified examples, only one corner portion on the optical path side of the illumination lens is chamfered to form a refracting portion. A prism structure having a reflecting surface may be used. A prism structure having three or more reflecting surfaces may also be used.
(2) The present invention can be applied to reading various optical information in addition to a barcode reader, a two-dimensional code such as QR code, PDF417, data matrix, maxi code, and RSS composite.

It is explanatory drawing which shows the partial internal structure of the barcode reader which concerns on 1st Embodiment. It is a top view which shows the partial internal structure of the barcode reader shown in FIG. It is explanatory drawing which shows the structure of a 1st illumination lens, (a) is the top view which looked at the 1st illumination lens from upper direction, (b) is the left view of (a), (c) is (a). FIG. 3 is an explanatory diagram showing a relationship between an angle of view of an imaging lens 40 and an emission angle of illumination light that is refracted by a first refracting unit 22 and is emitted from the front surface 23 of the first illumination lens 20. FIG. It is explanatory drawing which shows the incident angle and refraction angle in a prism. It is a top view corresponding to Drawing 2 in the example of a change of a 1st embodiment. FIG. 4 is a plan view corresponding to FIG. 3. It is a top view corresponding to Drawing 2 in a 2nd embodiment. FIG. 4 is a plan view corresponding to FIG. 3.

Explanation of symbols

10..Bar code reader, 20..First illumination lens, 22..First refraction section,
27 .. First guide member, 30... Second illumination lens, 32..
37 .. Second guide member 40.. Imaging lens 50.. First light source
51 .. Second light source, .alpha .. angle of view, .beta.

Claims (3)

An imaging lens for imaging the reflected light reflected by the recording surface on which the optical information is recorded;
First and second illumination lenses arranged with the optical path of the imaging lens interposed therebetween;
A first light source that emits light to the first illumination lens;
A second light source that emits light to the second illumination lens, and the first illumination lens diffuses the light emitted from the first light source to illuminate the optical information. The optical information reader is configured to illuminate the optical information by diffusing the light emitted from the second light source by the second illumination lens,
At the end of the first illumination lens on the optical path side, a part of the light emitted from the first light source within the range of the emission angle of the first light source is transferred to the first illumination lens side. A first refracting section is provided that refracts along the boundary of the optical path located at
At the end of the second illumination lens on the optical path side, a part of the light emitted from the second light source within the range of the emission angle of the second light source is transferred to the second illumination lens side. An optical information reader comprising a second refracting section that refracts so as to proceed along the boundary of the optical path located at the position.   2. The optical information reader according to claim 1, wherein an emission angle of light emitted from the first and second refracting portions is ½ of an angle of view of the imaging lens. Between the 1st light source and the 1st refracting part, the 1st guide member which guides a part of light emitted from the 1st light source to the 1st refracting part is provided. ,
A second guide member is provided between the second light source and the second refracting portion to guide part of the light emitted from the second light source to the second refracting portion. 3. The optical information reading apparatus according to claim 1, wherein the optical information reading apparatus is an optical information reading apparatus.

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