JP2001043302A - Information recording symbol reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To visually recognize the position of an information recording symbol from just above. SOLUTION: An information recording symbol reader 7 has an image sensor 21 which optically reads the information recording symbol 4 of a prescribed area, which is printed on a printed matter and the like, from a data reading port 15 and a decoding means converting the information recording symbol 4 into corresponding prescribed data based on picture data which is read by the image sensor 21. A transparent prism 14 in an almost triangle prism is installed in the data reading part 15 so that the oblique line face 14a turns upward. The image sensor 21 is arranged on an optical path which is made incident from the lower face 14b of the transparent prism 14 and is totally reflected by the oblique face 14a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for optically capturing an information recording symbol such as a two-dimensional bar code such as a bar code, particularly a data code, into an image sensor and converting the information recording symbol into a predetermined electric signal corresponding to the information recording symbol. The present invention relates to an information recording symbol reading device that reads data recorded in an information recording symbol after conversion.

[0002]

2. Description of the Related Art Barcodes have been mainly used as information recording symbols on which product information such as product numbers and price data are recorded, but recently, more product information can be recorded. Etc. are being adopted.

As such an information recording symbol reading device, a handy terminal or the like having an image pickup device such as a CCD, which is an image sensor, is usually used, and an information recording symbol reading port formed in these handy terminals is used. The information recording symbol is taken in through an optical system such as a lens and converted into an image signal by the CCD, and based on the image signal, a predetermined electric signal corresponding to each data recorded in the read information recording symbol. The signal is reproduced, and the product data or the like is stored or output to the outside.

[0004] Unless the entire information recording symbol such as a two-dimensional bar code is read from the reading port, it is not converted into predetermined data and a reading error occurs. It is necessary to arrange a handy terminal or the like so that the entire information recording symbol falls within a predetermined range, and if the alignment between the handy terminal and the information recording symbol is not properly performed, the reading must be repeatedly performed many times. There were times when I had to.

[0005] Therefore, as a method of solving these alignment problems, a mirror shutter or the like is provided in a path of light incident on the CCD, which is the image sensor, and the alignment is performed like a camera. There has been proposed a method in which a mirror shutter is closed to guide incident light to a CCD for reading, and a method in which image data converted by the CCD is displayed on a display device or the like to perform alignment.

[0006] However, although the above-mentioned methods can surely perform the positioning, when the mirror shutter or the like is provided, the optical system becomes complicated due to the mechanical operation, and the size of the obtained handy terminal is increased. In addition, there is a problem that the cost is high, and the method of performing the alignment by displaying the image on the display device or the like increases the cost because a high-resolution display device is provided, and consumes less power. There were problems such as an increase.

For this reason, the present inventors have previously disclosed in Japanese Patent Laid-Open No.
As described in Japanese Patent No. 7566, in order to facilitate the alignment between the handy terminal and the information recording symbol with a simple structure, the reading port is formed of a transparent member such as glass. There has been proposed a reading device that performs reading while visually confirming information recording symbols.

The fact that these reading openings are made of a transparent material such as glass so that the position of the information recording symbol to be read from the outside can be confirmed is a simple structure for positioning as described above. However, since it is necessary to dispose the CCD and the mirror above the information recording symbol to be read in the vertical direction, the position of the information recording symbol to be read is shifted obliquely through the transparent member such as glass. In some cases, it is difficult to confirm the position of the lens, and when the CCD or the like is disposed above the information recording symbol to be read in the vertical direction as described above, the focal length of the lens may be reduced. Since it is necessary to take it in the vertical direction, the handy terminal may become bulky and may not be suitable for the external shape of the product. Stability of the handy terminal at the time of Align is a problem of lowered.

[0009]

Therefore, by providing a transparent prism in the reading opening, the information recording symbol can be visually confirmed from above the transparent prism and easily positioned, and the transparent prism can be easily aligned. To partially reflect the image light of the information recording symbol
However, in this method, the total reflection surface of the transparent prism is touched by a finger or the like in the operation of the reading device, so that water or grease easily adheres to the total reflection surface, If such water or oil adheres, there is a problem that the above-mentioned total reflection is not performed well, the reflected light becomes uneven, and reading by the CCD may not be performed accurately.

Therefore, the present invention has been made in view of such a problem, and an information recording symbol reading apparatus capable of preventing occurrence of a reading error caused by adhesion of water or oil and fat to a total reflection surface. It is intended to provide.

[0011]

In order to solve the above-mentioned problem, an information recording symbol reading apparatus according to the present invention comprises an image recording symbol having a predetermined area printed on a printed material or the like optically read from a data reading port. An information recording symbol reading device, comprising: a sensor; and decoding means for converting the information recording symbol into corresponding predetermined data based on image data read by the image sensor. A transparent prism that totally reflects at least a part of the image light of the information recording symbol incident from the data reading port, and the total reflection surface of the transparent prism has a refractive index X of the transparent prism equal to one square root of 2; A low-refractive-index layer having a refractive index equal to or less than a value obtained by multiplying (1 / √2) is provided, and a low-refractive-index layer is provided on the optical path of the totally reflected image light. It is characterized in that a image sensor. According to this feature, the transparent prism has a refractive index on the total reflection surface that is 1/1 / of the refractive index X of the transparent prism.
Since the low-refractive-index layer having a thickness of 以下 2 or less has water and fats and oils attached to the surface of the low-refractive-index layer, even if these waters and fats and oils adhere, they are affected by these waters and fats and oils. Without this, uniform total reflection occurs at the interface between the low refractive index layer and the transparent prism, so that a reading error in the image sensor caused by the adhesion of water or oil can be prevented.

An information recording symbol reading device according to the present invention comprises:
It is preferable that the low refractive index layer is formed in a gap with a transparent member provided so as to cover the total reflection surface.
With this configuration, the refractive index of air with respect to a transparent glass material or a transparent resin generally used as a transparent prism is 1 / √2 or less of the refractive index X of the transparent prism, so that the low refractive index layer can be easily formed. Can be formed.

[0013] The information recording symbol reading device of the present invention comprises:
The transparent prism has a cross-sectional shape of a substantially right-angled isosceles triangle, and the transparent prism is arranged at an angle of 45 degrees with respect to the printed matter such that the total reflection surface is the hypotenuse surface. Is preferred. With this configuration, image light that is incident at the highest intensity from the lower surface of the transparent prism facing the data reading port and is vertical to the lower surface is totally reflected by the hypotenuse surface of the transparent prism. As a result, the reading sensitivity of the information recording symbol can be maximized.

The information recording symbol reading device of the present invention comprises:
A primary filter capable of transmitting other visible light without substantially transmitting predetermined wavelength light is provided on the external light incident surface of the transparent prism, and in an optical path to the image sensor,
Irradiating means for irradiating the information recording symbol by outputting light having a wavelength not transmitted by at least the primary filter;
It is preferable to provide a secondary filter that allows light of a wavelength not transmitted by the secondary filter to be transmitted preferentially and that transmits light of other wavelengths substantially untransmitted. In this way, disturbance light is prevented from entering the image sensor, and among the stable lights radiated from the irradiation unit, only light having a predetermined wavelength comes to enter the image sensor. The occurrence of a reading error or the like due to disturbance light can be prevented.

An information recording symbol reading device according to the present invention comprises:
It is preferable that the transparent member also serves as the primary filter. With this configuration, it is not necessary to provide the primary filter independently, and the structure can be simplified and the cost can be reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment) FIG. 1 shows an article ordering sheet 1 for catalog sales used in an embodiment of the present invention. A plurality of rectangular frames sectioned into a certain size include an area 2 for article display and an article 2 It is divided into an area 3 for displaying names, prices, and the like, and an area 5 for displaying a two-dimensional data symbol (data code) 4 as an information recording symbol.

A two-dimensional data symbol (hereinafter abbreviated as a data symbol) 4 forms a square, and merchandise information data such as a merchandise code, a merchandise name, an internal capacity, and a price corresponding to the data symbol 4 is previously converted and recorded. ing.

As shown in FIG. 1, the data symbol 4 printed on each of these areas 5 is read by disposing a handy terminal 7 as a reading device at a predetermined position on the upper surface thereof.

As shown in FIG. 2, the handy terminal 7 serving as an information symbol reader has a horizontally long appearance in which one end is inclined upward, and a function key is provided on the upper surface of the handy terminal 7. An input unit 10 including a numeric keypad and the like for inputting the number of products and the number of products is provided, and a liquid crystal display unit 13 capable of appropriately displaying input information and read information is formed. An illuminating button 11 for illuminating the data symbol 4 when aligning the data symbol 4 and a read button 12 for reading operation are provided on the side surface.

The handy terminal 7 is composed of a lower housing 8 and an upper housing 9. A lower end of the handy terminal 7 has a slightly larger reading than the data symbol 4 for reading the data symbol 4. An opening 15 is formed, and the lower surface of a substantially triangular prism-shaped transparent prism 14 is arranged in the reading opening 15 so as to face the reading opening 15 as shown in a cross section in FIG. Between the lower housing 8 and the upper housing 9 such that the window 6 provided on the inclined surface of the upper housing 9 is located immediately above the hypotenuse surface 14 a which is the total reflection surface of the prism 14. It is pinched.

The transparent prism 14 used in this embodiment
As shown in FIG. 4, the side surface 14c and the lower surface 14c
b is a right angle, and the angle between the hypotenuse surface 14a, the side surface 14c, and the lower surface 14b is 45 degrees, which is a right angle 2
In this embodiment, it is an isosceles triangle, and in this embodiment, it is a substantially right-angled isosceles triangle in which a vertex formed by the hypotenuse surface 14a and the lower surface 14b is cut out from the viewpoint of mounting and the like, and the hypotenuse surface 14a is used for ordering. The lower surface 14b is disposed so as to be parallel to the lower surface of the handy terminal 7 that contacts the ordering sheet 1 so that the angle is 45 degrees with respect to the sheet 1.

As described above, by disposing the transparent prism 14 in a shape of a substantially right-angled isosceles triangle so that the oblique surface 14a is at 45 degrees to the ordering sheet 1, the lower surface 14b The image light of the data symbol 4 having the highest intensity incident at right angles to the data symbol 4 is totally reflected by the oblique surface 14a and is incident on the image sensor 21 provided inside the handy terminal 7. However, the present invention is not limited to this, and the shape and arrangement method of the transparent prism 14 may be appropriately determined depending on the design of the optical system, the shape of the housing, and the like. Changes are optional. Further, it is optional to cut off the apex of the transparent prism 14 for the purpose of attachment or the like as in the present embodiment.

Further, as shown in FIG.
Red cut filter 2 as a primary filter that reflects red light and infrared light having a wavelength of about 660 nm or more and transmits visible light having a wavelength of less than about 660 nm.
4 is the hypotenuse surface (total reflection surface) 14 of the transparent prism 14
a so as to form a gap 25 as a low refractive index layer between the red cut filter 2 and the red cut filter 2.
4, red light having a wavelength of about 660 nm or more is excluded from external light incident from the hypotenuse surface 14a, and only visible light having a wavelength of less than about 660 nm is transmitted through the transparent prism 1.
4 is incident on the inside.

The refractive index of these low-refractive-index layers is determined to be a total refraction at the oblique surface (total reflection surface) 14 a of the transparent prism 14, and in particular, an appropriate refraction in which image light vertically incident on the lower surface is totally reflected. It is preferable that the refractive index be equal to or less than 1 / √2 of the refractive index X of the transparent prism 14 under the condition of total reflection as shown in FIG.

In this embodiment, the low-refractive-index layer is formed with a gap as described above. This is because the low-refractive-index layer is formed of a glass material or a transparent resin material which is usually used as the transparent prism 14. Since air has a low refractive index of X / √2 or less required for total reflection of X (mostly about 1.5), these low refractive index layers can be easily formed. Although preferred, the present invention is not limited to this. As shown in FIG. 6A, a material layer having a refractive index of 1 / √2 or less of the refractive index X of these transparent prisms 14 is formed on the hypotenuse surface. (Total reflection surface) 14a may be directly formed on the transparent prism, or as shown in FIG. 6B, a transparent prism may be formed by providing a gap 25 near the hypotenuse surface (total reflection surface) 14a. It may be a prism 14 ',
Further, as shown in FIG. 6 (c), a transparent prism provided with a transparent cover 26 which is a transparent member mounted so as to have an appropriate gap between the hypotenuse surface (total reflection surface) 14a. 14 ".

The size of the gap 25 is not particularly limited, but may be set to a minimum necessary gap, for example, several millimeters or less from the viewpoint of miniaturization of the apparatus.

In this embodiment, the transparent prism 1
4 is made of glass, and both end surfaces thereof are made of a rubbed glass having low transparency, and light is transmitted from the both end surfaces to the transparent prism 14.
Although it is designed to suppress leakage to the outside, in order to prevent such light leakage, it is also possible to use a mirror whose both end surfaces are formed by aluminum evaporation.

The above-mentioned red cut filter 24 may be any filter that blocks red and efficiently transmits visible light other than red. If there is no problem in practical use, a green color filter or a blue color filter that also blocks light of colors other than red and red can be used.

The present invention also relates to the red cut filter 2 described above.
The filter is not limited to 4, but is formed by thinly applying a paint containing a dye or the like that preferentially reflects the 660 nm red light to a transparent glass plate or the like, other than the red cut filter. You can do it,
A device that selectively transmits or reflects light of another wavelength may be used.

The main structure inside the handy terminal 7 will be described with reference to FIG. 3. An optical path 16 is formed inside the handy terminal 7 so as to be connected to the side surface 14c of the transparent prism 14 in the lateral direction. An illuminating device 18 which is an illuminating means composed of a red LED having an emission center wavelength of 660 nm for illuminating the data symbol 4 is provided at a position around the optical path. Lens 2 for guiding the red light from the illuminating device 18, which is reflected by the transparent prism 14 and whose course is changed by the transparent prism 14, to the image sensor 21 to form an image.
0 and an image sensor 21 for converting an image of the data symbol 4 into a predetermined electric signal sequence are stored.
A red transmission filter 19 as a secondary filter which transmits red light having a center wavelength of 660 nm from the illuminating device 18 and light having a wavelength in the vicinity thereof preferentially, and hardly transmits light of other wavelengths. Is arranged.

Although the red transmission filter 19 is used alone in this embodiment, the present invention is not limited to this. The red transmission filter 19 is directly attached to the image sensor 21. By using the function of the red transmission filter 19 or adding the function of the red transmission filter 19 to the lens 20, the number of components in the optical path may be reduced to reduce the cost.

Further, in this embodiment, the illuminating device 18 as the illuminating means is formed of a red LED as described above. The use of an LED, particularly a red LED, as described above, has a high luminous efficiency and is necessary. Since it is possible to reduce the power consumed with respect to the amount of light to be used, in the case of the portable terminal 7 which is driven by the built-in battery 22 and is portable as in this embodiment, However, the present invention is not limited to this, and it is preferable to use another light source such as a cold cathode tube or an EL light emitting element. You may do it.

The red light illuminated by the illuminating device 18 is reflected by the data symbol 4 as described above, passes through the reading port 15 which is the reflected light of the data symbol 4, and passes under the transparent prism 14. As shown in FIG. 3, the image light that is incident perpendicular to the direction is redirected by the hypotenuse surface 14 a of the transparent prism 14 and the red transmission filter 1 is turned on.
9, passes through the red transmission filter 19, forms an image on the image sensor 21 by the lens 20, and is converted into predetermined image data by the image sensor 21.

Of the red light illuminated by the illuminating device 18, of the image light not vertically incident on the lower surface of the transparent prism 14, the visible light having a wavelength of less than about 660 nm and the hypotenuse The visible light having a wavelength of less than about 660 nanometers incident on the surface 14a and reflected by the data symbol 4 exits from the hypotenuse surface 14a to the outside as shown in FIG. 4 and FIG. The position of the data symbol 4 can be visually confirmed above the hypotenuse surface 14a.

At this time, as shown in FIG.
4a, red light having a wavelength of about 660 nm or more is reflected and eliminated by the red cut filter 24, leaving only visible light having a wavelength of less than about 660 nanometers. Since the incident visible light having a wavelength of less than about 660 nm cannot pass through the red transmission filter 19, it passes through the red transmission filter 19 and
Since the light imaged on the image sensor 21 by 0 is only the red light illuminated by the illumination device 18,
With the configuration as in the above-described embodiment, it is possible to prevent the external light from adversely affecting reading in the image sensor 21.

The image data converted by the image sensor 21 is output to a decoding unit (not shown) mounted on the internal substrate 17 for reproducing data recorded in the data symbol 4 based on the image data. The reproduced data such as product information is stored in a storage means (not shown) such as a memory mounted on the internal substrate 17 of the handy terminal 7, and can be displayed on the liquid crystal display unit 13 or continuously to an external computer or the like. In FIG. 3, reference numeral 23 denotes an LCD mounted on an internal substrate 17 for displaying the liquid crystal display unit 13.
Module.

The operation of the handy terminal 7 of the present embodiment will be described below. First, as shown in FIG. 2, the handy terminal 7 is arranged on the product ordering sheet 1 and the desired data symbol 4 is entirely placed in the window. It is moved to the approximate center in the section 6 to perform positioning.

At this time, if the data symbol 4 is difficult to see due to little light from the outside world and the alignment is difficult,
By operating the illuminating button 11, the data symbol 4 is illuminated by the illuminating device 18. Of the image light, visible light having a wavelength of less than about 660 nm is visible through the hypotenuse surface 14 a of the transparent prism 14. It will be easier.

When the positioning is completed and the data symbol 4 is to be read, the reading button 12 is pressed instead of the illuminating button 11 so that the illuminating device 1 is pressed.
8, the red light of the predetermined wavelength is emitted, and the red light reflected by the data symbol 4 and light incident from the outside enter the red transmission filter 19.

The light incident on the red transmission filter 19 is first separated by the red transmission filter 19 into red light having a central wavelength of 660 nm in the light, light having a wavelength in the vicinity thereof, and other light. , Only the red light and light having a wavelength near the red light are preferentially transmitted to the lens 20.
To form an image on the image sensor 21.

The image of the data symbol 4 formed on the image sensor 21 is converted into image data as described above, and then the predetermined data recorded on the data symbol 4 is reproduced by the decoding unit. Is done.

As described above, as in the present embodiment, the transparent prism 14
By forming a low-refractive-index layer including the gaps 25 and the like so as to cover the hypotenuse surface (total reflection surface) 14a, water, oil, and the like adhere to the hypotenuse surface (total reflection surface) 14a by finger touch or the like. And the total reflection is made uniform, so that a reading error in the image sensor 21 can be prevented.

Although the embodiments of the present invention have been described with reference to the drawings, the present invention is not limited to these embodiments. Even if there are changes and additions without departing from the gist of the present invention, the present invention will be described. include.

For example, in the above-described embodiment, the red cut filter 24 is used as a transparent member. This is preferable because the structure can be simplified and the cost can be reduced by reducing the number of parts. The present invention is not limited to this, and the red cut filter and the transparent member may be provided separately.

In the above embodiment, the illuminating device 18 emits red light of 660 nm, and the transparent member is a red cut filter so as to correspond to the red light. However, the present invention is not limited to this. Instead, the wavelengths of these lights may be appropriately selected. For example, the illumination device emits green light of 570 nanometers, and the transparent member serves as a green cut filter, or emits near-infrared light from the illumination device. The transparent member that emits light may be used as an infrared cut filter.

In the above embodiment, two-dimensional data symbols are used as information recording symbols. However, the present invention is not limited to this. Needless to say, these information recording symbols may be one-dimensional bar codes. No.

[0047]

The present invention has the following effects.

(A) According to the first aspect of the present invention, since the transparent prism has a low refractive index layer on the total reflection surface, the refractive index of which is 1 / √2 or less of the refractive index X of the transparent prism. In addition, since water and oils and fats adhere to the surface of the low refractive index layer, even if these waters and oils and fats adhere, the low refractive index layer and the transparent prism are not affected by these waters and oils and fats. Since uniform total reflection occurs at the interface, it is possible to prevent a reading error in the image sensor caused by the adhesion of the water or the fat or oil.

(B) According to the second aspect of the invention, the refractive index of air with respect to a transparent glass material or a transparent resin usually used as a transparent prism is 1 / √2 or less of the refractive index X of the transparent prism. Thus, the low refractive index layer can be formed easily.

(C) According to the third aspect of the present invention, light perpendicular to the lower surface, which is image light incident at the highest intensity from the lower surface of the transparent prism facing the data reading port, is: Since the light is totally reflected by the oblique surface of the transparent prism and enters the image sensor, the reading sensitivity of the information recording symbol can be maximized.

(D) According to the fourth aspect of the present invention, disturbance light is prevented from entering the image sensor, and only light of a predetermined wavelength out of the stable light radiated from the irradiating means is provided. Is incident on the image sensor, so that occurrence of a reading error or the like due to disturbance light can be prevented.

(E) According to the fifth aspect of the present invention, it is not necessary to provide the primary filter independently, so that the structure can be simplified and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a product ordering sheet used in an embodiment of the present invention.

FIG. 2 is an external perspective view showing a handy terminal according to the embodiment of the present invention.

FIG. 3 is a sectional view A of the handy terminal according to the embodiment of the present invention.
It is sectional drawing in -A.

FIG. 4 is an enlarged sectional view showing a transparent prism used in an embodiment of the present invention and an optical path inside the transparent prism.

FIG. 5 is an enlarged sectional view showing a transparent prism used in an embodiment of the present invention and an optical path inside the transparent prism.

FIG. 6A is a cross-sectional view showing a transparent prism according to another embodiment of the present invention. (B) is sectional drawing which shows the transparent prism of other form of this invention. (C) is a sectional view showing a transparent prism of another embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between total reflection and a refractive index of a transparent prism used in an example of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Order sheet (printed matter) 2, 3, 5 Area 4 Two-dimensional data symbol (information recording symbol) 6 Window 7 Handy terminal (information recording symbol reader) 8 Lower housing 9 Upper housing 10 Input unit 11 Illumination Button 12 Read button 13 Liquid crystal display unit 14 Transparent prism 14 'Transparent prism 14 "Transparent prism 14a Oblique side 14b Lower surface 14c Side surface 15 Reading port 16 Optical path 17 Substrate 18 Illumination device 19 Red transmission filter (secondary filter) 20 Lens DESCRIPTION OF SYMBOLS 21 Image sensor 22 Battery 23 LCD module 24 Red cut filter (primary filter) 25 Gap 25 'Low refractive index layer 26 Transparent cover

Claims (5)

[Claims] An image sensor for optically reading an information recording symbol of a predetermined area printed on a printed material or the like from a data reading port, and a predetermined corresponding information recording symbol based on image data read by the image sensor. Decoding means for converting data into data, wherein the data reading port has a transparent prism that totally reflects at least a part of the image light of the information recording symbol incident from the data reading port. A low-refractive-index layer having a refractive index equal to or less than a value obtained by multiplying the refractive index X of the transparent prism by one-square root of two (1 / √2) on the total reflection surface of the transparent prism; ,
An information recording symbol reading device, wherein the image sensor is disposed on an optical path of the totally reflected image light. 2. The information recording symbol reader according to claim 1, wherein the low refractive index layer is formed in a gap with a transparent member provided so as to cover the total reflection surface. 3. The cross-sectional shape of the transparent prism is a substantially right-angled isosceles triangle, and the transparent prism is oriented at an angle of 45 degrees with respect to the printed matter so that the total reflection surface is the oblique surface. The information recording symbol reading device according to claim 1 or 2, wherein the information recording symbol reading device is arranged in the information recording symbol reading device. 4. A primary filter capable of transmitting other visible light while substantially not transmitting light of a predetermined wavelength is provided on an external light incident surface of the transparent prism, and at least an optical path to the image sensor is provided in a primary path. An irradiating means for outputting light having a wavelength not transmitted by the primary filter to illuminate the information recording symbol, and a secondary light having a wavelength which is not transmitted by the primary filter can be transmitted preferentially, and a light having a second wavelength substantially not transmitted by the primary filter. The information recording symbol reading device according to claim 1, further comprising a filter. 5. The information recording symbol reading device according to claim 4, wherein the transparent member also serves as the primary filter.