JP3829743B2 - Optical information recording medium and optical information reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical information recording medium on which information is recorded in an optically readable form, and an optical information reading apparatus for optically reading information recorded on such a medium.
[0002]
[Problems to be solved by the invention]
For example, in Japanese Patent No. 3223730, a mark such as a barcode is printed with an infrared absorbing ink (invisible ink), and the same mark is printed with a process ink (visible ink), and the mark is infraredly printed. A method of authenticating authenticity is disclosed in which, when irradiated with light and visible light, the infrared light is absorbed and the visible light is reflected, whereby the authenticity is determined.
[0003]
Japanese Patent Application Laid-Open No. 2000-295418 discloses a technique for increasing the amount of information recorded on a medium by printing a barcode using a phosphor that emits infrared light.
These conventional techniques are intended to increase the confidentiality of information or to improve the amount of information recorded.
[0004]
However, these conventional techniques have the following problems. First, since printing is performed using fluorescent ink that cannot be viewed with visible light, special components such as a light source or infrared sensor that emits infrared rays or ultraviolet rays are required, and the reading apparatus becomes expensive. Second, just invisible printing of the code as in Japanese Patent No. 3223730 does not know the position where the code is printed on the medium, and is not suitable for the case where the user manually reads the code.
[0005]
Thirdly, as in Japanese Patent Application Laid-Open No. 2000-295418, when performing invisible printing and visible printing in an overlapping manner, a reading device having both optical systems necessary for reading each of them is required. Therefore, there is a problem that the apparatus becomes large and expensive.
[0006]
The present invention has been made in view of the above circumstances, and its purpose is to enable reading of information by a reading apparatus having an inexpensive configuration, to improve the confidentiality of information, and to obtain an effect of preventing forgery. It is an object of the present invention to provide an optical information recording medium capable of recording information and an optical information reader for optically reading information recorded on such a medium.
[0007]
[Means for Solving the Problems]
According to the optical information recording medium of claim 1, the transparent code region comprising a transparent display unit comprising a transparent reflective layer that has substantial transparency to visible light and that regularly reflects visible light. And a visible code region configured to include a visible display unit that has optical characteristics different from those of the transparent display unit and is visually recognizable. “Specular reflection” refers to reflection performed in a state where the reflection angle is equal to the incident angle.
[0008]
That is, since the transparent reflection layer is transparent to visible light and regularly reflects visible light, if the invisible information is recorded by the transparent display unit, the reading device reflects the light regularly reflected by the transparent reflection layer. The information can be read by receiving light. In addition, it is possible to arrange information that can be read by visible light below the transparent reflective layer. Therefore, the transparent code area and the visible code area may be partially or entirely overlapped. it can.
Therefore, it is possible to ensure the confidentiality of information by recording invisible information, and it is also possible to increase the amount of information by overlappingly recording information that can be read by visible light. In addition, since the position of the transparent code area can be easily estimated based on the position of the visible code area, the user can easily read.
[0009]
According to the optical information recording medium of claim 2, the outer shape of the transparent reflective layer is configured to be smaller than the outer shape of the transparent display unit included in the transparent code area, and the transparent reflective layer is included in the transparent display unit. The reflectance of visible light in the transparent display unit is adjusted according to the proportion occupied.
[0010]
In other words, if the reflectance of regular reflection in the transparent display unit becomes too high, there is a risk that it may be difficult to discriminate between light and dark in the visible code area where the amount of reflected light is lower than that of regular reflection. Therefore, if comprised as mentioned above, it can adjust so that the contrast of a transparent display unit and the visible display area in a visible code area | region may become appropriate.
[0011]
According to the optical information recording medium of the third aspect, the size and interval of the transparent reflection layer imaged on the light receiving sensor of the reading device is made smaller than the resolution of the reading device that reads information. When the reading device receives the reflected light, the reflected light from the transparent display unit is captured in a plane. Therefore, the reflected light can be received stably.
[0012]
According to the optical information recording medium of the fourth aspect, in the transparent code area, the bright display unit and the dark display unit are configured by the relative difference in the area of the transparent reflective layer. That is, since a difference can be given to the reflectance of the transparent display unit depending on the area ratio of the transparent reflection layer, it is possible to give a difference to information read accordingly. Therefore, the amount of information to be recorded can be further increased.
[0013]
According to the optical information recording medium of the fifth aspect, the bright display unit and the dark display unit are configured in the visible code area by the relative difference of the irregular reflectance with respect to the visible light. Therefore, similarly to the fourth aspect, it is possible to give a difference to the information read according to the difference in the diffuse reflectance, so that the amount of information to be recorded can be further increased.
[0014]
According to the optical information recording medium of the sixth aspect, since the transparent code area and the visible code area are arranged adjacent to each other, the information recorded in each area can be collectively read by the reading device. Becomes easy.
[0015]
According to the optical information recording medium of claim 7, since the transparent code area and the visible code area are arranged so that one of the geometric centers is located inside the other area, Both areas can be read more easily.
[0016]
According to the optical information recording medium of the eighth aspect, one of the transparent code area and the visible code area is arranged so as to surround the outer peripheral side of the other area. If comprised in this way, arrangement | positioning of two area | regions can be performed efficiently and the reading which a reader will perform becomes easy.
[0017]
Furthermore, according to the optical information recording medium of the ninth aspect, since the transparent code area and the visible code area are arranged concentrically, both areas can be arranged more efficiently, and the space of the medium Can be used effectively.
[0018]
In addition, according to the optical information recording medium of claim 10, since the transparent code area is arranged outside the visible code area, it is arranged so as to make the visible code area small (compact). Can do. Therefore, the optical information recording medium can be made as inconspicuous as possible.
[0019]
According to the optical information recording medium of claim 11, when the information recorded in at least one of the transparent code area and the visible code area is read, the information is correct or incorrect. Place a check code for inspection (error check). For example, if each check code is arranged in each area, the reading apparatus can individually read information recorded in each area and perform an error check. Also, if both check codes are arranged in one area, the error check results in an error when the reading apparatus reads only the area including the check code. Therefore, information security can be improved for a reading apparatus that does not have the function of reading both areas simultaneously.
[0020]
According to the optical information reader of claim 12, the illumination light source includes reflected light in which the light emitted from the illumination light source is regularly reflected by the information recording surface of the optical information recording medium, and reflected light that is irregularly reflected. It arrange | positions so that it may receive with a light reception sensor. The decoder refers to the image signal output by the light receiving sensor, determines the brightness of the visible display unit arranged in the visible code area based on the first threshold value, and transmits the transparent code based on the second threshold value. The brightness of the transparent display unit arranged in the area is discriminated, and the information recorded in each area is decoded.
[0021]
That is, by configuring the optical information reader in this way, the information recorded in the visible code area and the information recorded in the transparent code area of the optical information recording medium both reflect visible light. By doing so, it becomes possible to read by a common optical system. Therefore, reading of an optical information recording medium on which more information is recorded or an optical information recording medium having a higher security level can be performed with a configuration that is less expensive than the conventional one.
[0022]
According to the optical information reading device of the thirteenth aspect, the optical axis of the illumination light source is set at a position symmetrical to the optical axis of the light receiving sensor with respect to the normal line standing on the information recording surface of the optical information recording medium. Therefore, the light regularly reflected on the information recording surface is surely received by the light receiving sensor. Accordingly, since the entire area of the light receiving sensor can be set as the regular reflection area, the degree of freedom in creating the code is further increased.
[0023]
According to the optical information reading device of the fourteenth aspect, the illumination light source receives the reflected light obtained by irregularly reflecting and specularly reflecting the light emitted from the illumination light source by the information recording surface of the optical information recording medium. The decoder determines the brightness of the visible display unit arranged in the visible code area based on the first threshold value, and determines the brightness of the transparent display unit arranged in the transparent code area based on the second threshold value. Discriminate between light and dark. Then, the information recorded in each area is decoded.
[0024]
That is, by configuring the optical information reader in this way, the information recorded in the visible code area and the information recorded in the transparent code area of the optical information recording medium both reflect visible light. By doing so, it becomes possible to read each. Therefore, similarly to the twelfth aspect, reading of an optical information recording medium on which more information is recorded or an optical information recording medium having a higher security level can be performed with a structure that is less expensive than the conventional one. it can.
[0025]
According to the optical information reading device of the fifteenth aspect, the first illumination light source receives only the reflected light, which is the light emitted from itself, which is irregularly reflected by the information recording surface of the optical information recording medium, by the light receiving sensor. The second illuminating light source is arranged such that the light emitted from itself is diffusely reflected and regularly reflected by the information recording surface by the light receiving sensor.
[0026]
The light receiving sensor outputs to the decoder an image signal corresponding to the amount of reflected light that has received the irregularly reflected light and the regular reflected light, and the decoder refers to the image signal so that the visible code region is based on the first threshold value. Discriminating the light and darkness of the visible display units arranged in the image, and discriminating the light and darkness of the transparent display units arranged in the transparent code area based on the second threshold value, and decoding the information recorded in the respective areas. .
That is, by dividing the illumination light source into the first and second light sources, adjustment is made so that irregular reflection light and regular reflection light generated on the information recording surface of the optical information recording medium are optimally received by the light receiving sensor. can do.
[0027]
According to the optical information reading device of the sixteenth aspect, the first illumination light source is configured such that the light received by the light receiving sensor is reflected by the light emitted from the first illumination light source that is irregularly reflected by the information recording surface of the optical information recording medium. The second illumination light source is arranged such that the light received by the light receiving sensor is reflected by the light emitted from the second illumination light source that is regularly reflected by the information recording surface.
[0028]
The light receiving sensor outputs the first and second image signals to the decoder according to the received irregularly reflected light amount and the regular reflected light amount, respectively, and the decoder refers to the first image signal and outputs the first threshold value. The light and darkness of the visible display unit arranged in the visible code area is determined based on the image quality, and the light and darkness of the transparent display unit arranged in the transparent code area is determined based on the second threshold with reference to the second image signal. Then, the information recorded in each area is decoded.
[0029]
That is, by configuring the optical information reader in this way, the information recorded in the visible code area and the information recorded in the transparent code area of the optical information recording medium both reflect visible light. This makes it possible to read based on the first and second image signals. And it becomes easy to handle the information regarding each area | region independently.
[0030]
According to the optical information reading device of the seventeenth aspect, the decoder detects an overlapping portion as an overlapping code region based on the positions of the visible code region and the transparent code region, and based on the overlapping code region. The information recorded in either the visible code area or the transparent code area is modulated and decoded.
[0031]
That is, the transparent code area having the transparent reflective layer can be arranged so as to overlap the visible code area. If the arrangement relationship between the visible code area and the transparent code area is known, these two areas are It is possible to detect an overlappingly set portion (overlapping code area). If the overlapping code area can be detected, the decoder modulates the information recorded in the visible code area and the transparent code area based on the overlapping (that is, the information originally recorded as an independent area). Can change the meaning). Therefore, when an overlapping code area is set on the optical information recording medium, decoding can be performed based on the information recorded in the area.
[0032]
According to the optical information reader of claim 18, when the decoder determines the brightness of the second image signal based on the first threshold, the brightness of the visible display unit arranged in the visible code area is determined. An overlapping code area is detected based on the inverted part. Based on the detected overlapping code area, information recorded in either the visible code area or the transparent code area is modulated and decoded.
[0033]
That is, when the brightness of the second image signal obtained by receiving the specularly reflected light is discriminated by the first threshold, the portion where the visible display unit and the transparent display unit overlap is discriminated by the second threshold. In contrast, the lightness and darkness are reversed. Therefore, the overlapping code area can be detected also by such a method, and when the overlapping code area is set on the optical information recording medium, the information recorded in the area can be detected. Can be decoded based on
[0034]
The optical information reader according to claim 19, wherein the first illumination light source is configured such that the reflected light obtained by specular reflection of the light emitted by the light source is reflected by the information recording surface of the optical information recording medium. It arranges so that it may not be received by. With this configuration, it is possible to accurately read information recorded in the visible code area and information recorded in the transparent code area by one light receiving sensor.
[0035]
According to the optical information reader of claim 20, when the read information includes a check code for checking the correctness of the information, the decoder reads the information read based on the check code. Since correctness is determined, it is possible to prevent information from being read in an incorrect state.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
1 to 8, a micro QR code (registered trademark, hereinafter simply referred to as a QR code) as a visible code area is used as a first embodiment of the present invention. explain. In this embodiment, the QR code is printed on a sheet as usual. Along with the QR code, different information is recorded depending on the presence or absence of a portion printed with transparent ink.
[0037]
First, the principle will be described with reference to FIG. FIG. 2 is a cross-sectional view of a portion of paper 1 on which black cells (dark cells) 2 used for QR codes are printed, a portion on which printing is not performed, and a portion on which black ink 2 is printed with transparent ink. It is. A transparent reflective layer 3 having substantial transparency with respect to visible light is formed in a portion where the transparent ink is printed, and the black cells 2 under the transparent ink layer are in a state that can be visually recognized.
[0038]
FIG. 2A shows the state of reflection that occurs on the surface of each part when light (visible light) incident perpendicularly on these parts is irradiated. At this time, in the portion (W) where the black cell 2 is not printed (that is, the white portion which is the ground color of the paper 1), the light is largely diffusely reflected, but in the portion (B) where the black cell 2 is printed, Is absorbed, so the reflection is small. That is, the QR code reading device recognizes the presence or absence of the black cell 2 and reads the QR code by the difference in the reflection state.
[0039]
In the portion (T) where the transparent reflective layer 3 is formed on the black cell 2, visible light is almost transmitted through the transparent reflective layer 3, so that reflection substantially occurs on the surface of the lower black cell 2. Is called. That is, the reflection of light is small. Therefore, when the vertically incident light is irradiated in this way, the QR code can be read as usual regardless of the presence or absence of the transparent reflective layer 3.
[0040]
FIG. 2B shows the state of reflection that occurs on the surface of each part when the part is irradiated with light having an incident angle of 45 degrees. At this time, similarly to (a), the portion (W) where the black cell 2 is not printed is highly irregularly reflected (the amount of reflected light is large), and the portion (B) where the black cell 2 is printed is slightly irregularly reflected ( Less reflected light).
[0041]
And in the part (T) in which the transparent reflective layer 3 is formed on the black cell 2, most of the light having an incident angle of 45 degrees is specularly reflected on the surface of the transparent reflective layer 3, and only a part of the incident light is reflected. The light passes through the transparent reflective layer 3 and is diffusely reflected by the surface of the black cell 2.
[0042]
That is, when the reflected light amounts of these three portions (W), (B), and (T) with respect to light having an incident angle of 45 degrees are compared, the relationship is (T)>(W)> (B) (see FIG. 3). ). Therefore, if light having an incident angle of 45 degrees is irradiated and the reflected light is received, it is possible to detect the portion where the transparent reflective layer 3 is formed (of course, the incident angle is limited to 45 degrees). It can be set to an arbitrary angle at which a sufficient amount of received light can be obtained by regular reflection). Specifically, the presence or absence of regular reflection can be determined by the threshold value H shown in FIG. 3, the position where the transparent reflective layer 3 is disposed can be detected, and the level of the irregular reflection level can be determined by the threshold value L. The position where the black cell 2 is arranged can be detected.
[0043]
The transparent ink for forming the transparent reflective layer 3 may be one obtained by dissolving a commonly used polymer material in water or an organic solvent (without adding a pigment or dye). Examples of the polymer material include polyvinyl alcohol, methyl cellulose, ethyl cellulose, cellulose acetate, polystyrene, polyvinyl chloride, a methacrylic resin alone or a copolymer, acrylic, styrene, silicon, polyisobutyl, and the like. There are polymers.
[0044]
For example, it is better to print a thick transparent ink on a surface with relatively large irregularities such as paper 1, and for a relatively flat surface such as a plastic sheet or film. For example, a thin transparent ink may be printed.
[0045]
FIG. 1 shows a configuration example of an information code 5 in which a transparent code region 7 having a transparent reflective layer 3 is added to a QR code 4. The information code 5 has a QR code 4 printed and arranged at the center thereof to form a visible code area. A transparent cell (transparent display unit) 6 formed by the peripheral transparent reflection layer 3 is the same size as the black cell 2. The transparent code area 7 is formed by printing. In FIG. 1, the transparent cell 6 is shown by hatching.
[0046]
In the information code 5, the geometric center of the QR code 4 and the geometric center of the transparent code area 7 are matched, that is, they are arranged in a concentric positional relationship.
[0047]
The QR code 4 is a combination of two-dimensionally combining a black cell 2 and a bright cell (visible display unit) 8 that is a white square as a portion where the black cell 2 does not exist, thereby expressing numbers, English letters, kanji, kana. , Symbols and the like are encoded and formed into a rectangular shape. Although details will be described later, the QR code 4 is optically read and decoded by the code reading device having a CCD camera or the like, which is composed of the black cell 2 and the bright cell 8. ing.
The specific pattern 4S of the QR code 4 indicates a reference position when the QR code 4 is read, and indicates the size of unit data (data cell) of the QR code 4.
[0048]
In the transparent code area 7, information is encoded in the same format as the QR code 4 or in a unique format depending on the presence or absence of the transparent cell 6. That is, the transparent code area 7 also forms a two-dimensional code.
[0049]
Then, in order to read the QR code 4 of the information code 5, it is only necessary to determine the presence or absence of the black cell 2 using the first threshold value for the amount of diffusely reflected light. To read out the transparent code area 7, What is necessary is just to discriminate | determine the presence or absence of the transparent cell 6 using a 2nd threshold value. In addition, what printed the information code 5 on the paper 1 comprises the optical information recording medium 100. FIG.
[0050]
Next, the procedure for generating the information code 5 will be described with reference to FIG. First, data to be recorded in the visible code area, that is, data to be recorded as QR code 4 is prepared (step A1), and the code size of the visible code area is determined based on the standard (QR code) (step A2). Subsequently, data to be recorded in the transparent code area 7 is prepared (step A3), and the code size of the transparent code area 7 is determined based on the standard (step A4). Then, a print pattern for each of the visible code area and the transparent code area 7 is created based on the data of steps A1 and A3 (step A5), and the print pattern is output to the printing apparatus for printing (step A6).
[0051]
FIG. 5 is a functional block diagram showing an electrical configuration of a code reader (optical information reader) 11 for reading the information code 5. The LEDs (illumination light sources) 13 to 18 of the light projecting / receiving unit 12 are used to irradiate the recording surface of the information code 5 with illumination light. FIG. 6 shows the configuration of an optical system centered on the light projecting / receiving unit 12. When the light projected by the LEDs 13 to 18 is reflected by the recording surface of the information code 5, the light is received by the light receiving sensor 20 including, for example, a CCD (Charge Coupled Device) area sensor via the light receiving lens 19. ing. The light receiving sensor 20 outputs the captured two-dimensional image as a horizontal scanning line signal to the comparison circuit 22 and the A / D conversion circuit 23 via the amplifier circuit 21.
[0052]
The comparison circuit 22 compares the input scanning line signal with the threshold value and outputs the binarized data to the memory 24 and the specific ratio detection circuit 25. The specific ratio detection circuit 25 detects a predetermined frequency component included in the code encoding pattern from the binarized scanning line signal data, and outputs the detection result to the memory 24. . The A / D conversion circuit 23 converts an analog scanning line signal supplied via the amplifier circuit 21 into digital data and outputs the digital data to the memory 24.
[0053]
The CPU (decoder) 26 controls the driving of the LEDs 13 to 18, the amplification factor of the amplification circuit 21, the threshold level applied to the comparison circuit 22, and the control of the A / D conversion circuit 23 and the specific ratio detection circuit 25. Is supposed to do. Further, the CPU 26 outputs a clock signal to the synchronization signal generation circuit 27. When the synchronization signal generation circuit 27 generates a synchronization signal based on the clock signal supplied from the CPU 26, the synchronization signal generation circuit 27 outputs the synchronization signal to the light receiving sensor 20, the specific ratio detection circuit 25, and the address generation circuit 28. The address generation circuit 28 generates a write address of the memory 24 by counting the synchronization signal and outputs it to the memory 24.
[0054]
Further, the CPU 26 is provided with an operation signal of the switch 29 for the user to perform an operation input, and the CPU 26 is configured to output a display signal to the liquid crystal display 30 and through the communication interface 31. Thus, communication with a host (not shown) can be performed, and processing such as transmission of data stored in the memory 24 is performed. The battery 32 supplies power to each part of the code reader 11.
[0055]
In FIG. 6, LEDs 13 and 14 are arranged on both sides of the light receiving lens 19, LEDs 15 and 16 are arranged on the left side of the LED 13, and LEDs 17 and 18 are arranged on the right side of the LED 14, respectively. The LEDs 15 and 16 and the LEDs 17 and 18 project light through diffusion plates 33 and 34 disposed below them, and are configured as diffusion light sources. Note that a larger number of illumination LEDs are actually arranged around the light-receiving lens 19, and the LEDs 13 to 18 show some of them.
[0056]
When the light source takes such an arrangement, on the plane where the information code 5 is read, the region corresponding to the central portion of the optical system is a region where irregular reflection occurs mainly due to the illumination light emitted from the LEDs 13 and 14 ( That is, the region (X) where regular reflection does not occur, and the region (Y) around the region (X) is mainly a regular reflection of illumination light emitted from the LEDs 15 and 16 and the LEDs 17 and 18, and the light receiving lens. 19 is an area incident on the light.
[0057]
Further, the LEDs 13 and 14 are arranged in such a positional relationship that the reflected light obtained by regular reflection of the light emitted by the LEDs 13 and 14 is not received by the light receiving sensor 20 as indicated by a broken line in FIG. . In addition, when the image of sufficient brightness is obtained with the illumination light by LED15-18, LED13,14 may be abbreviate | omitted.
[0058]
Next, the procedure in which the code reader 11 reads the information code 5 will be described with reference to FIG. FIG. 7 is a flowchart showing the control contents mainly performed by the CPU 26 of the code reader 11.
[0059]
First, the CPU 26 drives the LEDs 13 to 18 to perform light projection. Then, since the light reflected by the information recording surface of the information code 5 is received by the light receiving sensor 20, the image data of the gray value (grayscale image) is stored in the memory 24 (step B1).
[0060]
Subsequently, the CPU 26 discriminates the brightness of the image data stored in the memory 24 from the threshold value L (first threshold value) of the visible code area, converts it into binary image data, and stores it in a predetermined area of the memory 24 ( Step B2). Then, it is determined whether or not the specific pattern 4S indicating the reading reference position included in the QR code 4 exists in the binary image data (step B3). When the specific pattern 4S does not exist (step B4, “NO”), the process returns to step B1 to retry reading the information code 5.
[0061]
When the specific pattern 4S exists (step B4, "YES"), the CPU 26 determines the position of the data cell (black cell 2, bright cell 8) of the QR code 4 based on the position of the specific pattern 4S (step S4). B5) An array of binary data is determined from the light and dark states of the data cells (step B6). Then, the data (information) recorded in the QR code 4 is decoded (step B7).
[0062]
Next, the CPU 26 discriminates the brightness and darkness of the gray value image data stored in the memory 24 in step B1 based on the threshold value H (second threshold value) of the transparent code area 7, and converts it into binary image data. Is stored in a predetermined area of the memory 24 (step B8). Then, based on the position of the specific pattern 4S determined in step B3, the position of the transparent code area 7 is determined (step B9), and the array of binary data is determined from the light / dark state depending on the presence / absence of the transparent cell 6 (step B9). B10). Then, the data (information) recorded in the transparent code area 7 is decoded (step B11).
[0063]
By the way, in the information code 5 shown in FIG. 1, the transparent code area 7 is arranged adjacent to the outer periphery of the QR code 4 which is the visible code area. When the device 11 tries to read, it is necessary to make the boundary between the two areas coincide with the boundary between the reading areas (X) and (Y). Therefore, it is necessary to accurately align the two. That is, if the illumination light for irregular reflection for reading the QR code 4 is irradiated to the transparent code area 7, strong regular reflection is caused by the illumination, and accurate light reception is prevented.
[0064]
Therefore, as shown in FIG. 8, if a slight margin is provided between the visible code area 35 and the transparent code area 36, reading can be performed even if the alignment at the time of reading is performed to some extent. Is possible.
[0065]
As described above, according to the present embodiment, the optical information recording medium 100 includes an optical code different from the transparent cell 6 and the transparent code region 7 including the transparent cell 6 including the transparent reflective layer 3. A QR code 4 (visible code region) including the black cell 2 and the bright cell 8 having characteristics and visually recognizable is provided. Therefore, the confidentiality of the information can be ensured by recording invisible information in the transparent code area 7. In addition, since information that can be read by visible light can be recorded in the transparent code area 7 in an overlapping manner, the amount of information can be increased.
[0066]
Since the transparent code area 7 is arranged so as to surround the outer periphery side of the QR code 4 and adjacent to each other so as to be concentric, the two areas can be arranged efficiently. And the space of the recording medium 100 can be used effectively. Further, the code reader 11 can easily read the information stored in each area. Furthermore, since the visible code area is reduced by arranging the QR code 4 on the inner side, the recording medium 100 can be made as inconspicuous as possible.
[0067]
Further, according to the present embodiment, in the code reader 11, the LEDs 13 and 14 are arranged so that the reflected light irregularly reflected by the information recording surface of the recording medium 100 is received by the light receiving sensor 20, and the LEDs 15 to 18 are arranged. The light reflected by the information recording surface is reflected by the light receiving sensor 20. The light receiving sensor 20 outputs an image signal corresponding to the amount of reflected light received from each of the LEDs 13 to 18 to the CPU 26, and the CPU 26 is recorded in each of the QR code 4 and the transparent code area 7 based on the image signal. Configured to decode information.
[0068]
Therefore, since the optical information recording medium 100 having the transparent code region 7 can be read using only visible light, the code reader 11 can be configured at a lower cost than the conventional one.
[0069]
Further, the LEDs 13 and 14 are arranged in such a positional relationship that the light emitted from the LEDs 13 and 14 is regularly reflected by the information recording surface of the optical information recording medium 100 so that the light receiving sensor 20 does not receive the reflected light. The recorded information and the information recorded in the transparent code area 7 can be accurately read by one light receiving sensor 20, respectively.
[0070]
(Second embodiment)
9 to 12 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted, and only different parts will be described below. The information code 41 in the second embodiment is basically the same as in the first embodiment, but the transparent code area 42 is formed by printing and arranging the transparent cells 6 by the transparent transparent layer 3 around the QR code 4. However, as shown in FIG. 9A, a part of the transparent code area 42 is arranged so as to overlap the QR code 4.
[0071]
That is, as shown in FIG. 9 (b), when the hatching direction illustrating the transparent cell 6 is opposite to that shown in FIG. It shows what is printed and arranged in an overlapping manner. In addition, there is a part where the transparent cell 6 is also arranged with respect to the bright cell 8 in the QR code 4 region. The information code 41 printed on the paper 1 constitutes the optical information recording medium 101.
[0072]
Next, a method for reading the information code 41 will be described with reference to FIG. In the information code 41, a part of the transparent code area 42 is overlapped with the QR code 4. Of course, the black cell 2 and the bright cell 8 are visible for the overlapped portion. Therefore, the information of the QR code 4 similar to that of the first embodiment can be read by irradiating incident light substantially perpendicular to the information code 41 and receiving diffusely reflected light (see FIG. 10A). ).
[0073]
Then, if light obliquely incident on the information code 41 is irradiated, regular reflection is strongly generated in the transparent cell 6. In this case, the portion where the black cell 2 and the transparent cell 6 overlap is defined as the transparent cell 6. Recognized (see FIG. 10B). Therefore, if the gray value image data received at this time is binarized by the threshold value H, the position of the transparent cell 6 can be determined. Therefore, when the transparent cell 6 is expressed as “white”, as shown in FIG. become. That is, in this case, information recorded in the transparent code area 42 can be read.
[0074]
Further, when the light reception data of regular reflection is binarized by the threshold value L, the result is as shown in FIG. At this time, since the portion where the black cell 2 and the transparent cell 6 overlap (overlapping code) is recognized as the transparent cell 6, a form in which a part of the read data is modulated as shown in FIG. Can be read as
Therefore, in this case, data can be read in the three modes shown in FIGS. 10 (a), 10 (c), and 10 (d).
[0075]
FIG. 11 shows a procedure for generating the information code 41. Steps C1 to C5 are exactly the same as steps A1 to A5 in the first embodiment. In the subsequent step C6, first, the print pattern of the visible code area (QR code 4) is output to the printing apparatus for printing, and in the subsequent step C7, the print pattern of the transparent code area 42 is output to the printing apparatus for printing. Let
[0076]
The information code 41 can be read by the procedure shown in FIG. 7 using the code reader 11 in the first embodiment, but can also be read by the procedure shown in FIG. 12 using the same device 11. .
[0077]
That is, first, only the illumination light source (LEDs 13 and 14) for irregular reflection is turned on (step B0), and steps B1 to B7 are executed, so that only the information of the QR code 4 portion is read and decoded. In this case, the data stored in the memory 24 in step B1 corresponds to the first image signal.
[0078]
Next, only the illumination light sources (LEDs 15 to 18) for regular reflection are turned on (step B12), the information of the transparent code area 42 is read (step B13), and steps B8 to B11 are executed and decoded. In this case, the data stored in the memory 24 in step B13 corresponds to the second image signal.
[0079]
Up to this point, as in the first embodiment, this corresponds to the process of reading the information stored in the QR code 4 and the information stored in the transparent code area 42, respectively. That is, the information shown in FIGS. 10A and 10C is read out, and the processing related to the information reading shown in FIG.
[0080]
The CPU 26 performs the same processing as that in step B2 on the second image signal stored in the memory 24 in step B13, discriminates light and dark according to the threshold value L (first threshold value) of the visible code area, and converts it into binary image data. The data is converted and stored in a predetermined area of the memory 24. Then, in the same way as in step B6, light and dark are determined from the binarized data, and the code arrangement is determined. Here, the code is determined as shown in FIG.
[0081]
Then, an overlapping code area is detected based on the result of step B6 (step B14). Here, the “overlapping code area” is an area where an overlapping code in which the black cell 2 and the transparent cell 6 overlap is arranged. Next, decoding is performed based on the detected duplicate code area (step B15).
[0082]
For example, as shown in FIG. 10 (d), the decoding in step B15 is such that the black cell 2 that is a duplicate code of the part of the data of the QR code 4 decoded in step B7 is regarded as the bright cell 8. If decoding is performed, the information originally recorded as the QR code 4 is modulated and decoded.
[0083]
Alternatively, since the position of the transparent code area 42 is clear, if the transparent cell 6 that is the overlapping code is decoded as a non-transparent cell (that is, a dark cell), it is originally recorded as the transparent code area 42. Information is modulated and decoded. Any of these may be performed.
[0084]
As described above, according to the second embodiment, since the optical information recording medium 101 is arranged so that a part of the transparent code area 42 overlaps with the QR code 4, additional information is also provided in the overlapping part. Can be recorded. Therefore, the information recording density can be further improved.
[0085]
Further, according to the second embodiment, when the CPU 26 of the code reader 11 discriminates the brightness of the second image signal based on the threshold value L, the brightness of the black cell 2 arranged in the QR code 4 is inverted. Based on the detected portion, an overlapping code area is detected, and information recorded in either the QR code 4 or the transparent code area 42 is modulated and decoded based on the detected overlapping code area. Therefore, when the optical information recording medium 101 is configured to include an overlapping code area, decoding can be performed based on information recorded in the overlapping code area.
[0086]
(Third embodiment)
13 and 14 show a third embodiment of the present invention. In the third embodiment, the code reading device 44 is configured by replacing the light projecting / receiving unit 12 in the code reading device 11 with a light projecting / receiving unit 43. FIG. 13 shows only the portion of the light projecting / receiving unit 43.
[0087]
The LEDs 13 to 18 and the light receiving sensor 20 constituting the light projecting / receiving unit 12 in the code reader 11 are arranged in parallel so as to be vertically above the information code 5A. On the other hand, in the code reader / projector 44, the light projector 43T and the light receiver 43R are separated.
[0088]
The LEDs 45 and the diffuser plate 46 constituting the light projecting unit 43T are arranged in an inclined state on the upper left side in FIG. 13 of the information code 5A, and the light receiving sensor 47 constituting the light receiving unit 43R is arranged on the upper right side. In an inclined state. Further, the optical axis of the light projecting unit 43T and the optical axis of the light receiving unit 43R are arranged in a positional relationship that is symmetric with respect to the normal line standing on the information recording surface of the information code 5A.
[0089]
Accordingly, the light projected by the LED 45 is diffused by the diffusion plate 46 to become a surface light source, and is incident on the information code 5A from an oblique direction, so that the light receiving sensor 47 receives strong regular reflection light. The above constitutes the code reading device 44.
[0090]
In this case, the light receiving image of the light receiving sensor 47 of the information code 5A is distorted and formed because the light projecting / receiving axis is inclined. Therefore, in order to cope with this, the information code 5A is printed in a shape corrected in advance (see FIG. 14A). If comprised in this way, the light reception image in the light reception sensor 47 will become the same as what was seen from the front (refer FIG.14 (b)).
[0091]
As described above, according to the third embodiment, the LED 45 (and the diffusing plate 46) constituting the code reader 48 reflects the light emitted by itself by regular reflection by the information recording surface of the optical information recording medium 100A. Since the light and the irregularly reflected light are arranged so as to be received by the light receiving sensor 47, both the information recorded in the QR code 4 and the information recorded in the transparent code area 7 are visible light. Can be read by a common optical system.
[0092]
Therefore, when the optical information recording medium 100A is read, the information recorded in each area can be compared with the code reading device 11 in the first embodiment without performing alignment at the time of reading. all Visible Since it can be read by light, the user can easily read. In addition, the degree of freedom in creating the information code is increased.
[0093]
Further, since the optical axis of the illumination light source is arranged at a position symmetrical to the optical axis of the light receiving sensor 47 with respect to the normal line standing on the information recording surface of the optical information recording medium 100A, it is regularly reflected on the information recording surface. The received light is surely received by the light receiving sensor 47.
[0094]
(Fourth embodiment)
15 and 16 show a fourth embodiment of the present invention. In the fourth embodiment, the reflectance of the transparent cell is adjusted when a pattern or the like is printed on the paper 48 on which the information code is printed and there are ground colors (in this case, colors other than white and black). That is, in FIG. 15A, the portion where the transparent cell (transparent display unit) 49 is printed is shown by hatching.
[0095]
In FIG. 15B, the ground color of the paper 48 is represented by arranging circles hatched in three different directions in correspondence with the dots of the three primary colors of RGB. In FIG. 15B, a frame surrounded by a solid line is the transparent cell 49.
[0096]
On the other hand, the transparent cell (transparent display unit) 50 shown in FIG. 16 has 16 small circular transparent reflective layers 51 arranged in a matrix in the cell 50 (see (b)), and the outline frame size is Since it is made to be the same as that of the transparent cell 49, the reflectance of the transparent cell 50 is smaller than that of the transparent cell 49. In this way, the average reflectance of the transparent cell 50 can be set to a desired value. FIG. 16A conceptually shows the arrangement of the transparent reflection layer 51, not the actual reflection.
[0097]
That is, if the reflectance of the transparent cell is too high, a phenomenon similar to halation in a photograph may occur, and it may be considered that the reading of the QR code 4 using irregular reflection having a smaller reflected light amount than regular reflection may be hindered. is there.
[0098]
In this case, since the dot diameter of the transparent reflective layer 51 can be reduced to about 0.01 to 0.05 mm, the dot diameter and the interval between the dots are set larger than the resolution of the code reader 11 (or 44). It should be small enough. With such a configuration, the code reader 11 side does not recognize the transparent reflective layer 51 individually, and thus the reflected light of the transparent cell 50 is captured as a surface light source.
[0099]
As described above, according to the fourth embodiment, the outer diameter and interval of the transparent reflecting layer 51 are made smaller than the outer diameter of the transparent cell 50, and the transparent reflecting layer 51 occupies a transparent ratio in the transparent cell 50. Since the average reflectance of the cell 50 is adjusted, the contrast between the transparent cell 50 and the QR code 4 can be adjusted to be appropriate, and the QR code 4 can be read satisfactorily. .
[0100]
And since the dimension and space | interval of the transparent reflection layer 51 are made smaller than the resolution | decomposability of the code reader 11, the code reader 11 comes to catch the reflective surface of the transparent cell 50 in plane, and reflection of the transparent cell 50 is carried out. Light can be received stably.
Even if the background color of the paper is white, the reflectance of the transparent cell 50 can be adjusted similarly.
[0101]
(5th Example)
FIG. 17 shows a fifth embodiment of the present invention. The fifth embodiment is characterized by the arrangement of error check codes accompanying information codes. FIG. 17 conceptually shows an arrangement of check codes, in which error check codes 52E and 53E are arranged in a visible code area 52 and a transparent code area 53 such as QR code 4, respectively. is there. The check code used in the QR code 4 is a Reed-Solomon code that can be corrected. Moreover, FIG. 17 does not represent an actual arrangement form, but conceptually shows the arrangement form.
[0102]
With such a configuration, since the visible code area 52 and the transparent code area 53 can be read independently, even a conventional reader that does not support reading of the transparent code area 53 in the present invention can be used. Only the visible code area 52 can be read out.
[0103]
(Sixth embodiment)
FIG. 18 shows a sixth embodiment of the present invention. The sixth embodiment is slightly different from the fifth embodiment, in which check code codes 52E and 53E in both the visible code area 52 and the transparent code area 53 are collectively arranged on the visible code area 52 side.
[0104]
With this configuration, if only the visible code area 52 is read by a conventional reading apparatus that does not support reading of the transparent code area 53, a read error occurs due to the check code 53E, and thus reading is performed. It is not possible. Therefore, information security can be improved.
Of course, the check code may be arranged only in the transparent code area.
[0105]
(Seventh embodiment)
FIG. 19 shows a seventh embodiment of the present invention. The seventh embodiment shows an example in which a code other than the QR code 4 is used as the visible code area. That is, FIG. 19A shows an example using a data matrix 54, FIG. 19B shows a barcode (JAN) 55, and FIG. 19C shows PDF 417 and 56 as visible code areas. Then, outside these visible code areas, transparent code areas 57, 58 and 59 are added to form information codes 60, 61 and 62, respectively.
Needless to say, these may be arranged so that the visible code area and the transparent code area partially overlap as in the second embodiment.
[0106]
The present invention is not limited to the embodiments described above and shown in the drawings, and the following modifications or expansions are possible.
The format of the information recorded in the visible code area is not limited to the micro QR code 4, and any other optically readable information such as QR code, Maxicode, and stacked barcode two-dimensional code may be used.
The specific pattern may be arranged in the transparent code area.
The arrangement form of the visible code area and the transparent code area is other than that, for example, as in the first embodiment, the QR code 4 and the transparent code area 7 are concentric (the geometric center of both is Do not have to be arranged).
[0107]
Further, the arrangement may be such that both are arranged vertically or horizontally. At this time, as shown in the first embodiment, the two regions may be arranged adjacent to each other or may be arranged so as to have a predetermined interval.
As for the method of detecting the overlapping code area, the decoder may be configured so that the overlapping part is detected as the overlapping code area based on the positions of the visible code area and the transparent code area. That is, if the arrangement relationship between the visible code area and the transparent code area is known, a portion where these two areas are set in an overlapping manner can be detected as an overlapping code area.
In the fourth embodiment, a transparent cell (bright display unit, dark display unit) having a relative difference in the area of the transparent reflective layer 51 may be provided in the transparent code region. That is, since the difference in the reflectance of the transparent cell can be given depending on the area ratio of the transparent reflective layer 51, it is possible to give a difference to the information read accordingly. Therefore, the amount of information to be recorded can be further increased.
[0108]
The code readers 11 and 44 may be configured to read and decode the error check codes 52E and 53E in the fifth or sixth embodiment to detect or correct information reading errors.
Only the error check code relating to either the visible code area or the transparent code area may be arranged.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of an information code according to a first embodiment of the present invention, in which a transparent code area is added to a QR code.
FIG. 2A is a reflection state when visible light incident perpendicularly to an information recording surface of a recording medium is irradiated, and FIG. 2B is incident with an inclination of about 45 degrees with respect to the information recording surface. The figure which shows the reflection state when it irradiates visible light
FIG. 3 is a diagram showing light reception levels of light reflected on each part of the recording medium.
FIG. 4 is a diagram for explaining an information code generation procedure;
FIG. 5 is a functional block diagram showing an electrical configuration of a code reader for reading an information code.
FIG. 6 is a diagram showing a configuration of an optical system centered on a light projecting / receiving unit.
FIG. 7 is a flowchart showing the contents of control performed mainly by the CPU of the code reader.
FIG. 8 is a view showing a state where a slight margin is provided between a region where a visible code is actually printed and a transparent code region;
FIG. 9 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.
FIGS. 10A and 10B show a reading state of an information code, where FIG. 10A shows a reflection state when incident light that is substantially perpendicular to the information code is irradiated, and FIG. (C) is a state in which the image signal received for (b) is binarized by a threshold value H, and (d) is a diagram showing a state in which the image signal received for (b) is binarized by a threshold value L.
11 is equivalent to FIG.
FIG. 12 is a view corresponding to FIG.
FIG. 13 is a view corresponding to FIG. 6 showing a third embodiment of the present invention.
14 (b) shows an information code whose shape has been corrected, and FIG. 14 (a) shows an image of the information code formed on the light receiving sensor of the code reader.
FIG. 15 is a fourth embodiment of the present invention, and shows a state in which transparent cells similar to those of the first embodiment are printed on a sheet having a ground color, and FIG. 15B is a partially enlarged view of FIG. Figure shown
FIG. 16 is a view corresponding to FIG. 15 showing a case where a transparent cell is configured by printing a small transparent reflective layer in a matrix on a paper having a background color by printing or the like.
FIG. 17 is a diagram showing an arrangement of error check codes accompanying information codes according to the fifth embodiment of the present invention.
18 is a diagram corresponding to FIG. 17 and showing a sixth embodiment of the present invention.
FIG. 19 shows a seventh embodiment of the present invention, in which (a) is a data matrix, (b) is a bar code, and (c) is a PDF417 as a visible code area.
[Explanation of symbols]
2 is a black cell (visible display unit), 3 is a transparent reflective layer, 4 is a QR code (visible code region), 4S is a specific pattern, 5 is an information code, 6 is a transparent cell (transparent display unit), and 7 is a transparent code. Area, 8 is a bright cell (visible display unit), 13 to 18 are LEDs (light source for illumination), 20 is a light receiving sensor, 26 is a CPU (decoder), 41 is an information code, 42 is a transparent code area, 44 is a code reading Device, 45 LED (illumination light source), 47 light receiving sensor, 49 and 50 transparent cells (transparent display units), 51 a transparent reflective layer, 52 a visible code region, 53 a transparent code region, and 52E and 53E Error check code, 54 is a data matrix (visible code area), 55 is a barcode (visible code area), 56 is PDF417 (visible code area), 57 to 59 are transparent code areas, 60 62 information code, 100, 100A, 101 denotes an optical information recording medium.

Claims (20)

A transparent code area configured to include a transparent display unit having a transparent reflection layer that has substantial transparency to visible light and regularly reflects visible light, and in which optically readable information is recorded;
A visible code area having optical characteristics different from the transparent display unit, including a visible display unit that can be visually recognized, and in which optically readable information is recorded;
An optical information recording medium, which is arranged in at least one of the transparent code area and the visible code area and comprises a reading reference position and a specific pattern indicating the size of the display unit. The outer shape of the transparent reflective layer is configured to be smaller than the outer shape of the transparent display unit included in the transparent code region,
The optical information recording medium according to claim 1, wherein the transparent display unit has a visible light reflectance adjusted by a ratio of an area occupied by the transparent reflective layer in the region. The size and interval of the transparent reflecting layer constituting the transparent pattern formed on the light receiving sensor of the reading device for reading information is configured to be smaller than the resolution of the reading device. The optical information recording medium according to claim 2. The transparent code area is
A bright display unit having a relatively large area of the transparent reflective layer;
4. The optical information recording medium according to claim 2, wherein the transparent reflective layer is composed of a dark display unit having a relatively small area. The visible code region is
A bright display unit with a relatively large diffuse reflectance,
5. The optical information recording medium according to claim 1, wherein the optical information recording medium is composed of a dark display unit having a relatively low irregular reflectance. 6. The optical information recording medium according to claim 1, wherein the transparent code area and the visible code area are arranged adjacent to each other. 7. The optical information recording according to claim 6, wherein the transparent code area and the visible code area are arranged such that one of the geometric centers is located inside the other area. Medium. 8. The optical information recording medium according to claim 7, wherein one of the transparent code area and the visible code area is arranged so as to surround the outer peripheral side of the other area. 9. The optical information recording medium according to claim 8, wherein the transparent code area and the visible code area are arranged concentrically. The optical information recording medium according to claim 9, wherein the transparent code area is disposed outside the visible code area. When at least one of the transparent code area and the visible code area, information recorded in at least one area is read, a check code for checking the correctness of the information is disposed. The optical information recording medium according to claim 1, wherein: An optical information reader that optically reads information recorded on an optical information recording medium according to any one of claims 1 to 11, comprising an illumination light source, a light receiving sensor, and a decoder.
The illumination light source receives light reflected by the information recording surface of the optical information recording medium and reflected light irregularly reflected by the information recording surface by the light receiving sensor. Arranged as
The light receiving sensor outputs an image signal corresponding to the amount of reflected light received to the decoder,
The decoder refers to the image signal to determine the brightness of the visible display unit arranged in the visible code area based on a first threshold value for determining the brightness of the diffusely reflected light, and to determine the brightness of the regular reflected light. An optical information reading apparatus characterized by discriminating the brightness of a transparent display unit arranged in the transparent code area based on a second threshold value to be discriminated, and decoding information recorded in each area. The optical axis of the illumination light source is disposed at a position symmetrical to the optical axis of the light receiving sensor with respect to a normal line standing on an information recording surface of the optical information recording medium. 12. The optical information reader according to 12. An optical information reader that optically reads information recorded on an optical information recording medium according to any one of claims 1 to 11, comprising an illumination light source, a light receiving sensor, and a decoder.
The illumination light source is arranged so that the light emitted from itself is diffusely reflected and regularly reflected by the information recording surface of the optical information recording medium, and received by the light receiving sensor.
The decoder discriminates the brightness of a visible display unit arranged in the visible code area based on a first threshold for discriminating the brightness of diffusely reflected light, and based on a second threshold for discriminating the brightness of regular reflected light. An optical information reader configured to discriminate light and dark of a transparent display unit arranged in the transparent code area and to decode information recorded in each area. The illumination light source is
1st illumination arrange | positioned so that only the irregularly reflected light may be received by the said light receiving sensor among the reflected light in which the light which self emitted was irregularly reflected and specularly reflected by the information recording surface of the said optical information recording medium A light source for
The second light source for illumination is arranged such that the light emitted from itself is diffusely reflected and regularly reflected by the information recording surface of the optical information recording medium. ,
The light receiving sensor is configured to receive the irregularly reflected light and specularly reflected light and output an image signal corresponding to the received reflected light amount to the decoder;
The decoder refers to the image signal to determine the brightness of the visible display unit arranged in the visible code area based on a first threshold value for determining the brightness of the diffusely reflected light.
By referring to the image signal, the brightness of the transparent display unit arranged in the transparent code area is discriminated based on the second threshold value for discriminating the brightness of the regular reflection light, and recorded in the respective areas. 15. The optical information reader according to claim 14, wherein the optical information reader is configured to decode information. The illumination light source is
A first illuminating light source arranged so that the light emitted from itself is reflected by the information sensor surface of the optical information recording medium.
A second illumination light source arranged so that the light emitted from itself is regularly reflected by the information recording surface of the optical information recording medium is received by the light receiving sensor;
The light receiving sensor receives the irregularly reflected light, outputs a first image signal corresponding to the received reflected light amount to the decoder, receives the regular reflected light, and receives a first reflected light amount corresponding to the received reflected light amount. 2 image signals are output to the decoder;
The decoder
By referring to the first image signal, based on a first threshold value for determining the brightness of the diffusely reflected light, determine the brightness of the visible display unit arranged in the visible code area,
By referring to the second image signal, the brightness of the transparent display unit arranged in the transparent code area is discriminated based on the second threshold value for discriminating the brightness of the regular reflection light, and recorded in each area. 15. The optical information reading device according to claim 14, wherein the optical information reading device is configured to decode the recorded information. The decoder detects, as an overlapping code area, a portion where both overlap based on the positions of the visible code area and the transparent code area, and based on the overlapping code area, the visible code area or the transparent code area 17. The optical information reader according to claim 12, wherein the information recorded in any of the above is modulated and decoded. When the decoder determines brightness of the second image signal based on the first threshold value, an overlapping code area is based on a portion where the brightness of a visible display unit arranged in the visible code area is inverted The information recorded in either the said visible code area | region or the said transparent code area | region is modulated and decoded based on the said duplication code area | region, It is comprised so that it may decode. An optical information reading apparatus. The first illumination light source is arranged such that the light emitted from itself is regularly reflected by the information recording surface of the optical information recording medium so that the reflected light is not received by the light receiving sensor. The optical information reading device according to claim 16. The decoder has a function of determining whether the read information is correct based on the check code when the read information includes a check code for checking the correctness of the information. An optical information reading device according to any one of claims 12 to 19.

Images