Optical code, method of producing optical code, method of authenticating optical code, device for reading optical code, and reading assist device

A method of producing an optical code in which data to be decoded is recorded, the code comprising:

• a pattern of a plurality of light-color modules having high visible light reflectance;
• a plurality of dark-color modules having visible light reflectance lower than the visible light reflectance of the light-color modules, the data being expressed by the light-color and dark-color modules;
• and
• a fixed region in which the light-color modules and the dark-color modules are positionally fixedly arranged in advance, the light-color and dark-color modules in the fixed region providing a pattern assisting optical reading of the optical code,
• wherein:
• at least either the light-color modules or the dark-color modules include a first module and a second module having reflectances different from each other for invisible light of a predetermined wavelength;
• the light-color modules and the dark-color modules are recorded as a module pattern that is different between when irradiated with the visible light and when irradiated with the invisible light having the predetermined wavelength;
• and
• at least either the light-color modules or the dark-color modules included in the fixed region consist of the first module and the second module, the first module and the second module being positionally fixed in advance in the fixed region,
• the method comprising:
• a first step of deciding a pattern of the light-color modules and the dark-color modules of the optical code used for recording the data;
• a second step of deciding either a first module having high reflectance for invisible light of a predetermined wavelength or a second module having low reflectance for the invisible light of a predetermined wavelength, for each of the dark-color modules decided in the first step;
• and
• a third step of forming the first module on a front surface of a light-color base layer having high reflectance for the visible light and the invisible light of a predetermined wavelength by providing a first dark-color layer that transmits the invisible light of a predetermined wavelength, and forming the second module on the front surface of the light-color base layer by providing a second dark-color layer that absorbs the invisible light of the predetermined wavelength.

A method of authenticating an optical code, in which data to be decoded is recorded, the code comprising:

• a pattern of a plurality of light-color modules having high visible light reflectance;
• a plurality of dark-color modules having visible light reflectance lower than the visible light reflectance of the light-color modules, the data being expressed by the light-color and dark-color modules;
• and
• a fixed region in which the light-color modules and the dark-color modules are positionally fixedly arranged in advance, the light-color and dark-color modules in the fixed region providing a pattern assisting optical reading of the optical code,
• wherein:
• at least either the light-color modules or the dark-color modules include a first module and a second module having reflectances different from each other, other for invisible light of a predetermined wavelength;
• the light-color modules and the dark-color modules are recorded as a module pattern that is different between when irradiated with the visible light and when irradiated with the invisible light having the predetermined wavelength;
• and
• at least either the light-color modules or the dark-color modules included in the fixed region consist of the first module and the second module, the first module and the second module being positionally fixed in advance in the fixed region;
• the method comprising:
• a visible light imaging step of capturing an image of the optical code in the visible light;
• an invisible light imaging step of capturing an image of the optical code with the invisible light of a predetermined wavelength;
• a visible light discriminating step of discriminating between the light-color modules and the dark-color modules, for at least part of modules included in the optical code, based on an image captured in the visible light imaging step;
• an invisible light discriminating step of discriminating between a module having high reflectance for the invisible light of a predetermined wavelength and a module having low reflectance for the invisible light of a predetermined wavelength, for at least part of modules included in the optical code, based on an image captured in the invisible light imaging step;
• an invisible light module discriminating step of discriminating between the first module and the second module, for at least part of modules, based on results of the visible light discriminating step and the invisible light discriminating step;
• and
• an authenticating step of authenticating the optical code, based on a pattern of the first module and the second module, the pattern being discriminated at least in the invisible light module discriminating step.

A reading device for an optical code in which data to be decoded is recorded, the code comprising:

• a pattern of a plurality of light-color modules having high visible light reflectance;
• a plurality of dark-color modules having visible light reflectance lower than the visible light reflectance of the light-color modules, the data being expressed by the light-color and dark-color modules;
• and
• a fixed region in which the light-color modules and the dark-color modules are positionally fixedly arranged in advance, the light-color and dark-color modules in the fixed region providing a pattern assisting optical reading of the optical code,
• wherein:
• at least either the light-color modules or the dark-color modules being include a first module and a second module having reflectances different from each other for invisible light of a predetermined wavelength;
• the light-color modules and the dark-color modules are recorded as a module pattern that is different between when irradiated with the visible light and when irradiated with the invisible light having the predetermined wavelength;
• and
• at least either the light-color modules or the dark-color modules included in the fixed region consist of the first module and the second module, the first module and the second module being positionally fixed in advance in the fixed region,
• the reading device comprising:
• an irradiation unit that applies the visible light and the invisible light of a predetermined wavelength to the optical code;
• and
• an imaging unit capable of capturing an image in reflected light which is a reflection of the light applied to the optical code from the irradiation unit, wherein
• the imaging unit includes
• a visible light recorded data reader reading the data, based on a pattern of modules obtained from an image captured in reflected light that is a reflection of the visible light;
• and
• an invisible light recorded data reader reading the data, based on a pattern of modules obtained from an image captured in reflected light that is a reflection of the invisible light of a predetermined wavelength.

A reading device for an optical code in which data to be decoded is recorded, the code comprising:

• a pattern of a plurality of light-color modules having high visible light reflectance;
• a plurality of dark-color modules having visible light reflectance lower than the visible light reflectance of the light-color modules, the data being expressed by the light-color and dark-color modules;
• and
• a fixed region in which the light-color modules and the dark-color modules are positionally fixedly arranged in advance, the light-color and dark-color modules in the fixed region providing a pattern assisting optical reading of the optical code,
• wherein:
• at least either the light-color modules or the dark-color modules include a first module and a second module having reflectances different from each other for invisible light of a predetermined wavelength;
• the light-color modules and the dark-color modules are recorded as a module pattern that is different between when irradiated with the visible light and when irradiated with the invisible light having the predetermined wavelength;
• and
• at least either the light-color modules or the dark-color modules included in the fixed region consist of the first module and the second module, the first module and the second module being positionally fixed in advance in the fixed region,
• the reading device comprising:
• an imaging unit that is provided with an imaging device capable of capturing an image in the visible light and invisible light;
• an invisible light filter that shields the visible light and transmits the invisible light of a predetermined wavelength;
• a visible light filter that shields the invisible light of a predetermined wavelength and transmits the visible light;
• a mount/demount mechanism that is capable of selectively mounting/demounting the visible light filter and the invisible light filter to/from a light path;
• and
• an irradiation unit that is capable of emitting at least the invisible light of a predetermined wavelength, wherein the reading device is configured to execute:
• a visible light imaging process of capturing an image of the optical code, with the invisible light filter being demounted from the light path and the visible light filter being mounted to the light path;
• an invisible light imaging process of capturing an image of the optical code imaged in the visible light imaging process, with the visible light filter being demounted from the light path and the invisible light filter being mounted to the light path;
• a visible light recording data reading process of reading the data, based on an image captured in the visible light imaging process;
• and
• an authenticating process of authenticating the optical code, at least based on an image captured in the visible light imaging process.

A reading assist device that allows a smartphone to read a pattern of the modules readable when visible light is applied to an optical code, and a pattern of the modules readable when the invisible light of a predetermined wavelength is applied to the optical code, data to be decoded is recorded in the optical code, the optical code comprising:

• a pattern of a plurality of light-color modules having high visible light reflectance;
• a plurality of dark-color modules having visible light reflectance lower than the visible light reflectance of the light-color modules, the data being expressed by the light-color and dark-color modules;
• and
• a fixed region in which the light-color modules and the dark-color modules are positionally fixedly arranged in advance, the light-color and dark-color modules in the fixed region providing a pattern assisting optical reading of the optical code,
• wherein:
• at least either the light-color modules or the dark-color modules include a first module and a second module having reflectances different from each other for invisible light of a predetermined wavelength;
• the light-color modules and the dark-color modules are recorded as a module pattern that is different between when irradiated with the visible light and when irradiated with the invisible light having the predetermined wavelength;
• and
• at least either the light-color modules or the dark-color modules included in the fixed region consist of the first module and the second module, the first module and the second module being positionally fixed in advance in the fixed region,
• the assist device comprising:
• a housing that has at least a top plate and side walls and is configured to arrange the optical code at a bottom portion;
• an irradiation unit that is disposed inside the housing to apply the invisible light of a predetermined wavelength to the bottom portion of the housing;
• and
• a control unit that controls application of the invisible light of a predetermined wavelength by the irradiation unit, wherein:
• the top plate of the housing is provided with a camera opening enabling passage of at least visible light and the invisible light of a predetermined wavelength, with an illumination opening enabling passage of at least visible light being formed near the camera opening;
• the reading assist device further includes a light-receiving sensor inside the housing to detect light passing through the illumination opening;
• and
• the control unit allows the irradiation unit to apply the invisible light of a predetermined wavelength under conditions that no light passing through the illumination opening is being detected by the light-receiving sensor, and does not allow the irradiation unit to apply the invisible light of a predetermined wavelength when light passing through the illumination opening is at least being detected by the light-receiving sensor.