Key system

Abstract

To achieve high key performance. [Solution] The lock system according to the embodiment comprises a light source, a spectral pattern generation unit, a sensor, and an unlocking determination unit. The light source generates light. The spectral pattern generation unit generates incident light of a spectral pattern defined for a spectral pattern based on one spectral pattern selected from a plurality of spectral pattern generation patterns, based on the light generated from the light source. The sensor has one structural pattern selected from a plurality of structural patterns, and when incident light of the spectral pattern is incident on it, it outputs a different current value according to the selected one structural pattern. The unlocking determination unit determines, based on the output of the sensor when the incident light is incident, whether the combination of the one spectral pattern generation pattern and the one structural pattern of the sensor is an expected combination.

Description

[Technical Field]

[0001] This invention relates to a key system. [Background technology]

[0002] Currently available keys on the market include physical keys used in homes (rotary disc cylinder locks, dimple cylinder locks), smart keys used in cars, fingerprint and facial recognition used in digital devices, and IC card keys used in ID cards and hotel rooms.

[0003] However, physical keys, smart keys, and IC card keys carry the risk of being illegally unlocked through picking, relay attacks, and skimming. Furthermore, fingerprint and facial recognition systems have the potential for similar fingerprints or facial features in some individuals, and there are concerns about unlocking through impersonation. Additionally, fully digital keys such as smart keys and IC card keys may see a dramatic decrease in performance as quantum computers develop.

[0004] Therefore, it is desirable to develop a highly secure key system. From this perspective, a key system using optical sensors is a possibility.

[0005] Patent Document 1 describes an electromechanical surface plasmon resonance sensor in which an electrode, a silicon semiconductor film, and a plasmon resonance electrode are arranged in this order, and a prism is placed on top of them to measure current or voltage.

[0006] Furthermore, Patent Document 2 describes a spectroscopic sensor that utilizes surface plasmon resonance generated by a diffraction grating structure. In a spectroscopic sensor that utilizes surface plasmon resonance generated by a diffraction grating structure, for example, a diffraction grating structure (uneven structure) is included on the silicon surface, and a plasmon resonance material such as a thin film of gold is placed on top of it. When light of a specific wavelength is incident at a specific angle, plasmon resonance occurs, and the current generated at this time is detected. Here, in a diffraction grating type plasmon resonance sensor, the relationship between the angle of incident light and the wavelength at which plasmon resonance occurs is derived from a predetermined relational equation and is known. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 7313607 [Patent Document 2] Patent No. 7084020 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, there is no simple relationship between the intensity of the incident light and the output current of the plasmon resonance sensor, making it difficult to easily predict the output of the plasmon resonance sensor from the intensity of the incident light. Furthermore, unlike general spectroscopic sensors, which have no dependence on the sensor structure with respect to wavelength, the output of a diffraction grating type plasmon resonance sensor depends on the diffraction grating structure. This property could be used to create a key system.

[0009] The present invention has been made in view of the above, and provides a key system that achieves high key performance. [Means for solving the problem]

[0010] To solve the above-mentioned problems and achieve the objective, the key system of the embodiment comprises a light source, a spectral pattern generation unit, a sensor, and an unlocking determination unit. The light source generates light. The spectral pattern generation unit generates incident light of a spectral pattern defined for a spectral pattern based on one spectral pattern selected from among a plurality of spectral pattern generation patterns, based on the light generated from the light source. The sensor has one structural pattern selected from among a plurality of structural patterns, and when light of a specific wavelength is incident on it, it outputs a different current value according to the selected structural pattern. The unlocking determination unit determines, based on the output of the sensor when the incident light is incident, whether the combination of the one spectral pattern generation pattern and the one structural pattern of the sensor is the expected combination. [Effects of the Invention]

[0011] The key system according to the present invention can achieve high key performance. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a diagram showing an example of the configuration of a key system according to an embodiment. [Figure 2] Figure 2 is a diagram showing an example of the arrangement of each component of the key system according to the embodiment. [Figure 3] Figure 3 shows an example of the structure of a plasmon resonance sensor in a key system according to this embodiment. [Figure 4] Figure 4 illustrates the operating principle of the plasmon resonance sensor in the key system according to this embodiment. [Figure 5] Figure 5 illustrates the conversion of wavelength-intensity data and angle-current value data in a plasmon resonance sensor. [Figure 6] Figure 6 shows an example of a different diffraction grating structure for a plasmon resonance sensor in a key system according to the embodiment. [Figure 7]FIG. 7 is a diagram for explaining unlocking determination processing in the key system according to the embodiment. [Figure 8] FIG. 8 is a diagram for explaining unlocking determination processing in the key system according to the embodiment. [Figure 9] FIG. 9 is a flowchart for explaining the flow of processing performed by the key system according to the embodiment. [Figure 10] FIG. 10 is a diagram for explaining the theoretical key difference number of the key system according to the embodiment. [Figure 11] FIG. 11 is a diagram comparing the advantages and disadvantages of a plurality of key systems including the key system according to the embodiment.

Mode for Carrying Out the Invention

[0013] (Embodiment) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] First, an outline of the key system according to the embodiment will be described.

[0015] Among spectroscopic sensors, there is a spectroscopic sensor called a diffraction grating structured plasmon resonance sensor. In a diffraction grating type plasmon resonance sensor, typically, a diffraction grating structure (concavo-convex structure) is included on the silicon surface, and a plasmon resonance material film such as a thin gold film is disposed thereon. When light of a specific wavelength is incident at a specific angle, plasmon resonance occurs, and energy is transferred to electrons inside the atoms constituting the plasmon resonance material. A current generated by this energy exceeding the Schottky barrier between silicon and the atoms (for example, gold) constituting the plasmon resonance material is detected as a current.

[0016] There is a certain relationship between the wavelength at which surface plasmon resonance occurs and the angle of incidence of the incident light. Therefore, by irradiating a sensor with an incident angle of incident light changed by vibration, measuring the current value with respect to the angle, and converting the measured current value into wavelength and the intensity of incident light at that wavelength, spectroscopic analysis can be performed. Specifically, wavelength-incident light intensity data can be obtained by applying the inverse matrix of a matrix called the device characteristic matrix to the angle-current value data obtained during measurement. Here, the device characteristic matrix is ​​data created from the wavelength of the incident light, the incident light intensity, the angle, and the current value measured in advance, and is device-specific data.

[0017] In diffraction grating type plasmon resonance sensors, the relationship between the angle of incident light and the wavelength at which plasmon resonance occurs is derived from a predetermined relation and is known. However, there is no simple relation between the intensity of incident light and the output current of the plasmon resonance sensor, making it difficult to easily predict the output of the plasmon resonance sensor from the intensity of incident light.

[0018] In addition, unlike general spectroscopic sensors, which have no dependence on the sensor structure with respect to wavelength, the output of a diffraction grating type plasmon resonance sensor can vary greatly depending on the pitch of the unevenness of the sensor's diffraction structure, the ratio of the width of the unevenness, the height of the protrusions, and the thickness of the gold film.

[0019] The key system according to this embodiment utilizes this property of a diffraction grating type plasmon resonance sensor to create a key system with high key performance.

[0020] More specifically, in the key system according to the embodiment, one spectral generation pattern is selected from among a plurality of spectral generation patterns, and the incident light of the spectral pattern generated by the selected spectral generation pattern is input to the plasmon resonance sensor. Here, spectral pattern generation is performed using, for example, dyes. As an example, spectral pattern generation is performed by generating incident light of a spectral pattern defined for a mixed pattern based on a mixed pattern selected from a plurality of dye mixed patterns. As a result, different spectral patterns of incident light to the plasmon resonance sensor are generated by different mixed patterns of multiple dyes.

[0021] On the other hand, the plasmon resonance sensor itself has a single structural pattern selected from among several structural patterns. In other words, various plasmon resonance sensors with different diffraction structures are available.

[0022] Furthermore, the key system according to the embodiment includes an unlocking determination unit, which determines whether the combination of the selected spectral generation pattern (dye mixing pattern) and the diffraction structure pattern is the expected combination based on the output of the plasmon resonance sensor when the incident light of the generated spectral pattern is incident on the plasmon resonance sensor, and performs an unlocking determination.

[0023] In such a key system, the spectral generation pattern (dye mixing pattern) is 10 5 The number of theoretical key differences is approximately 10. Also, the number of diffraction structures in a plasmon resonance sensor is 10. 3 The theoretical number of key differences is approximately 10 types, and as a result, the entire key system has 10 16 It is possible to achieve a theoretical number of key differences of a certain degree.

[0024] Furthermore, considering the security of the key system, and considering the spectral generation pattern (dye mixing pattern), even if the spectrum after dye mixing is known, it is difficult to accurately calculate the mixing ratio of the dyes unless the spectra of each mixed dye are known. Also, even if the generated spectral pattern is known, it is difficult to actually reproduce that spectral pattern with a light source. Moreover, considering the diffraction structure of the plasmon resonance sensor, the structure of the plasmon resonance sensor is not visible to the naked eye, and expensive equipment such as an electron microscope is required to confirm the structure, and destructive testing is also required. Furthermore, even if the structure is known, expensive machinery such as semiconductor manufacturing equipment is required to manufacture the structure, making key duplication practically difficult.Therefore, the key system according to this embodiment can achieve high key performance.

[0025] Next, the structure of the key system 300 according to the embodiment will be described in detail using Figures 1 and 2. Figure 1 is a diagram showing an example of the structure of the key system 300 according to the embodiment, and Figure 2 is a diagram showing an example of the arrangement of each element of the key system 300.

[0026] As shown in Figure 1, the lock system 300 comprises a lock 100 and a key 200. The lock 100 comprises a battery 4, a light source 3a, a spectral pattern generation unit 2a, a sensor 1a, a control unit 5a, a power supply and communication port 6a, an electromagnetic shutter 7a, and an unlocking determination unit 8. The key 200 comprises a light source 3b, a spectral pattern generation unit 2b, a sensor 1b, a control unit 5b, a power supply and communication port 6b, and an electromagnetic shutter 7b.

[0027] Furthermore, Figure 2 shows an example of the arrangement of each component shown in Figure 1. As shown in Figure 2, the lock 100 includes, for example, a light source 3a, a spectral pattern generation unit 2a, an electromagnetic shutter 7a, a sensor 1a, a control unit 5a, an unlocking determination unit 8, a battery 4, and a power supply & communication port 6a, while the key 200 includes, for example, a light source 3b, a spectral pattern generation unit 2b, an electromagnetic shutter 7b, a sensor 1b, a control unit 5b, and a power supply & communication port 6b. Here, the incident light of the spectral pattern generated by the spectral pattern generation unit 2a on the lock 100 side based on the light source 3a passes through the electromagnetic shutter 7a and is incident on the sensor 1b on the key 200 side, and the control unit 5b acquires the current value output by the sensor 1b. That is, when the lock 100 and the key 200 are connected, the light source 3a, spectral pattern generation unit 2a, and electromagnetic shutter 7a of the lock 100, and the sensor 1b and control unit 5b of the key 200, generate a single optical system. Similarly, the incident light of the spectral pattern generated by the spectral pattern generation unit 2b on the key 200 side based on the light source 3b passes through the electromagnetic shutter 7b and is incident on the sensor 1a on the lock 100 side, and the control unit 5a acquires the current value output by the sensor 1a. In other words, when the lock 100 and the key 200 are connected, the light source 3b, spectral pattern generation unit 2b, and electromagnetic shutter 7b of the key 200, the sensor 1a of the lock 100, and the control unit 5a form a single optical system. In Figure 2, the incident light generated by the spectral pattern generation unit 2a or 2b is shown as being incident on the sensor 1a or 1b from the horizontal direction, but in reality, the incident light is incident on the sensor 1a or 1b from a perpendicular or oblique direction. Also, the specific shape details of the lock 100 and key 200 are omitted in Figure 2, but in reality, the lock 100 and key 200 have a structure in which the protrusion of the key 200 can be inserted into the recess of the lock 100.

[0028] Returning to Figure 1, light sources 3a and 3b are light sources that generate light. When the power and communication ports 6a and 6b, described later, are connected, the electromagnetic shutters 7a and 7b open, and light sources 3a and 3b light up. Since sensors 1a and 1b, described later, are sensors that mainly detect light in the near-infrared (NIR) region using plasmon resonance, light sources suitable for this purpose are selected as light sources 3a and 3b.

[0029] The spectral pattern generation unit generates incident light with a spectral pattern defined for a spectral pattern, based on a light source, based on one spectral pattern selected from among multiple spectral pattern generation patterns. For example, spectral pattern generation unit 2a generates incident light with a pattern defined for a spectral pattern, based on light emitted from light source 3a, based on one spectral pattern selected from among multiple spectral pattern generation patterns. Similarly, spectral pattern generation unit 2b generates incident light with a pattern defined for a spectral pattern, based on light emitted from light source 3b, based on one spectral pattern selected from among multiple spectral pattern generation patterns.

[0030] Here, when incident light with a defined spectral pattern is generated based on a mixed pattern selected from multiple dye mixed patterns, the mixed pattern selected from the multiple dye mixed patterns becomes an example of the spectral pattern generation unit 2a or 2b.

[0031] For example, let's say there are five types of pigments, "A," "B," "C," "D," and "E," and the amount of each pigment can be divided into four levels: "0," "1," "2," and "3." Here, for example, if the amount is "0," the amount of pigment is 0. If the amount of pigment when the amount is "3" is x (mol), then when the amount is "1," the amount of pigment is 1 / 3 × x (mol), and when the amount is "2," the amount of pigment is 2 / 3 × x (mol). If one of the amounts from 0 to 3 is selected for pigment A, one of the amounts from 0 to 3 is selected for pigment B, one of the amounts from 0 to 3 is selected for pigment C, one of the amounts from 0 to 3 is selected for pigment D, and one of the amounts from 0 to 3 is selected for pigment E, the resulting mixture pattern will be the mixed pattern selected from the multiple pigment mixed patterns. In this case, the mixed pattern selected from the multiple pigment mixed patterns is 4 5 This results in a mixing pattern of different combinations of pigments. Note that the number of pigments and the number of pigment concentration levels are not limited to the above example; for example, there may be 5 types of pigments and approximately 10 concentration levels. In this case, the number of mixing pattern combinations is 10 5 It becomes a type.

[0032] Thus, the spectral pattern generation unit 2a generates incident light of a spectral pattern defined for a spectral pattern based on a spectral pattern selected from among multiple spectral pattern generation patterns, using light generated from the light source 3a. Similarly, the spectral pattern generation unit 2b generates incident light of a spectral pattern defined for a spectral pattern based on a spectral pattern selected from among multiple spectral pattern generation patterns, using light generated from the light source 3b. For example, if the spectral pattern generation units 2a and 2b are mixed patterns selected from mixed patterns of multiple dyes, the spectral pattern generation units 2a and 2b irradiate the mixed pattern of multiple dyes with light generated from the light sources 3a and 3b, and acquire the transmitted or reflected light as the incident light of a spectral pattern defined for the mixed pattern.

[0033] Although the embodiments described above describe a case in which the functions of the spectral pattern generation units 2a and 2b are realized by a mixed pattern selected from a plurality of dye mixed patterns, the embodiments are not limited to these examples. That is, it is sufficient that incident light with a defined spectral pattern is generated at the stage when it is incident on the sensor 1a or 1b, and for example, the spectral pattern generation units 2a and 2b may be realized by a bandpass filter (BPF) that transmits light in a predetermined wavelength range. In this case, the transmitted wavelength range is selected from a plurality of options, and the spectral pattern generation units 2a and 2b generate incident light with a defined spectral pattern based on the light generated from the light sources 3a and 3b by transmitting light in the selected wavelength range.

[0034] As another example, the spectrum of the light source itself may be selected from multiple options, in which case the light source also functions as a spectral pattern generator. In this case, the light source corresponding to the selected spectral pattern generates incident light with a predetermined spectral pattern.

[0035] The electromagnetic shutters 7a and 7b open and close their blades by electromagnetic drive to control the exposure of the light source. For example, when the electromagnetic shutter 7a is open, the incident light of the spectral pattern generated by the spectral pattern generation unit 2a based on the light source 3a is incident on the sensor 1b. Similarly, when the electromagnetic shutter 7b is open, the incident light of the spectral pattern generated by the spectral pattern generation unit 2b based on the light source 3b is incident on the sensor 1a.

[0036] Sensor 1a has one structural pattern selected from among multiple structural patterns, and when incident light of the spectral pattern generated by the spectral pattern generation unit 2b is incident on it, it outputs a different current value depending on the selected structural pattern. Similarly, sensor 1b has one structural pattern selected from among multiple structural patterns, and when incident light of the spectral pattern generated by the spectral pattern generation unit 2a is incident on it, it outputs a different current value depending on the selected structural pattern.

[0037] Here, sensors 1a and 1b are plasmon resonance sensors that generate plasmon resonance when light of a specific wavelength is incident on them, and the multiple structural patterns are, for example, multiple diffraction structural patterns. The multiple diffraction structural patterns referred to here mean diffraction structural patterns in which at least one of the parameters such as the pitch of the irregularities in the plasmon resonance sensor, the ratio of the width of the irregularities, the height of the protrusions, or the thickness of the metal thin film in the plasmon resonance sensor is different.

[0038] The structures of sensors 1a and 1b in the key system 300 according to this embodiment will be described using Figures 3 to 6. Figure 3 shows an example of the structure of a plasmon resonance sensor 1. The plasmon resonance sensor 1 in Figure 3 is an example of sensor 1a in the lock 100 and sensor 1b in the key 200.

[0039] The plasmon resonance sensor 1, for example, consists of a diffraction grating structure 22 including continuous convex and concave portions, a metal thin film 10 formed on the surface of the diffraction grating structure 22, and a semiconductor layer 11 having the diffraction grating structure 22. It is connected to a control unit 5 that detects the current generated by surface plasmon resonance generated by the metal thin film 10. The plasmon resonance sensor 1 also includes a MEMS (Micro Electro Mechanical Systems) mechanism (not shown) for changing the angle of the sensor with respect to incident light.

[0040] The metal thin film 10 is formed on the surface of the diffraction grating structure 22 and is made of a metal that can excite surface plasmon resonance when infrared light is incident at a specific incident angle. Typically, gold (Au) is selected as the metal thin film 10, but the embodiment is not limited to this, and silver (Ag), aluminum (Al), copper (Cu), platinum (Pt), palladium (Pd), zinc (Zn), sodium (Na), etc. may also be used. In addition to metals, other materials for the metal thin film 10 include metal nitrides such as titanium nitride (TiN), and metal oxides such as ITO (Indium tin oxide) and FTO (Fluorine-doped tin oxide). The thickness 24 of the metal thin film is, for example, 50 nm.

[0041] The semiconductor layer 11 is formed of a semiconductor such as silicon. When sufficient energy is transferred to the electrons of the metal thin film 10 through surface plasmon resonance to overcome the Schottky barrier between the metal thin film 10 and the semiconductor layer 11, the electrons from the metal thin film 10 move to the semiconductor layer 11, generating an electric current. This current is detected by the ammeter 13 of the control unit 5.

[0042] The diffraction grating structure 22 includes continuous convex and concave portions, and diffraction occurs in the reflected light according to the diffraction grating structure. As a result, interference occurs in the reflected light, and the intensity of the reflected light varies depending on the angle. Here, if the direction of the intensity variation of the reflected light caused by incident light incident at a specific angle is the surface direction of the diffraction grating structure 22, i.e., the horizontal direction in Figure 3, then surface plasmon resonance occurs depending on the type of atoms constituting the metal thin film 10. Surface plasmon resonance occurs at a specific incident angle θ with respect to the wavelength λ of the incident light. Parameters of the diffraction grating structure 22 that affect the spectral characteristics of the plasmon resonance sensor 1 include the pitch 21 (d2) of the uneven structure, the width 20 (d1) of the convex portions, the ratio of the widths of the uneven structure (d2 / d1), the height 23 of the convex portions, and the thickness 24 of the metal thin film.

[0043] The control unit 5 is composed of, for example, a metal layer and a sensor 13 such as a current sensor or potential sensor connected thereto, and detects electrons that have moved from the metal thin film 10 to the semiconductor layer 11 due to energy exceeding the Schottky barrier being provided by surface plasmon resonance.

[0044] The operating principle of the plasmon resonance sensor 1 will be explained using Figure 4. First, consider the case where the plasmon resonance sensor 1 is incident on with monochromatic light of a wavelength that causes surface plasmon resonance at a given incident light angle θ. For example, when incident light 40a of monochromatic light of a wavelength that causes the greatest intensity of surface plasmon resonance at an incident light angle θ1 is incident, the sensor output when the incident light angle θ is changed will have the shape shown by curve 40b. Similarly, for example, when incident light 41a and 42a of monochromatic light of wavelengths that cause the greatest intensity of surface plasmon resonance at incident light angles θ2 and θ3, respectively, the sensor output when the incident light angle θ is changed will have the shapes shown by curves 41b and 42b, respectively.

[0045] In actual measurements, the incident light 43 input to the plasmon resonance sensor 1 is typically white light, not monochromatic light. When there is no object to be measured 45, the sensor output when the incident light angle θ is changed takes the shape shown, for example, by curve 44a. When there is an object to be measured 45, a portion of the spectrum of the incident light 43 is absorbed by the object 45, so the sensor output when the incident light angle θ is changed takes the shape shown, for example, by curve 44b. By taking the difference between curve 44a and curve 44b, spectroscopy can be performed with respect to the object to be measured 45.

[0046] Here, when light consisting of a superposition of multiple wavelengths is incident, the angle-current value data I is expressed by the following equation (1), using the device characteristic matrix R and wavelength-intensity data P.

[0047]

number

[0048] Here θ SPRi θ represents the i-th incident angle, and λ represents the i-th incident angle. j 'j' represents the j-th wavelength. Equation (1) shows that applying the device characteristic matrix R to the wavelength-intensity data P yields angle-current value data I. That is, for example, as shown in Figure 5, applying the device characteristic matrix R to data 50, which is the wavelength-intensity data P, yields data 51, which is the angle-current value data I. Conversely, applying the inverse of the device characteristic matrix R to data 51, which is the angle-current value data I, yields data 50, which is the wavelength-intensity data P. In other words, the plasmon resonance sensor 1 can obtain data 50, which is the wavelength-intensity data P of the incident light, by applying the inverse of the device characteristic matrix R to data 51, which is the angle-current value data I obtained from the data obtained from the current detection unit 30, and perform spectroscopy.

[0049] To explain the significance of using the plasmon resonance sensor 1 in the key system 300, the plasmon resonance sensor 1 converts incident light data with a specific spectrum, given by wavelength-intensity data P, into angle-current value data I through a structure-dependent transformation of the sensor. Here, the relationship between the angle of the incident light and the wavelength that causes plasmon resonance can be easily determined by a known relationship, but there is no simple relationship between intensity and current value, making it difficult to calculate one data from the other. In other words, unlike general sensors such as prism-dispersive sensors where the input is equal to the output, or Fourier transform type or Fabry-Perot type sensors where the output can be easily calculated from the input using Fourier transform, the plasmon resonance sensor 1 converts the input signal into an output signal in a way that cannot be easily calculated on the sensor. Therefore, the security is improved when used in a key system.

[0050] As mentioned earlier, sensors 1a and 1b have one diffraction structure pattern selected from among multiple diffraction structure patterns. Figure 6 shows examples of multiple possible diffraction structure patterns. For example, by changing the pitch 21 (d2) of the uneven structure shown in Figure 6(a), the ratio of the widths of the uneven structure (d2 / d1) shown in Figure 6(b), the height 23 of the protrusions shown in Figure 6(c), and the thickness 24 of the metal thin film shown in Figure 6(d), sensors with different spectral characteristics can be obtained. Sensors 1a and 1b are plasmon resonance sensors 1 that correspond to one diffraction structure pattern selected from among multiple diffraction structure patterns with different spectral characteristics.

[0051] Returning to Figure 1, the control units 5a and 5b are a control unit 5 that includes, for example, an ammeter 13, and acquires the current values ​​output from the sensors 1a and 1b.

[0052] Furthermore, power and communication ports 6a and 6b are power and communication ports that supply power from the lock 100 to the key 200, transmit current value data acquired by the control unit 5b of the key 200 from the key 200 to the lock 100, and enable communication between the lock 100 and the key 200. When power and communication ports 6a and 6b are connected, power is supplied from the lock 100 to the key 200. Also, data acquired by the control unit 5b of the key 200 is transmitted from the key 200 to the unlocking determination unit 8 of the lock 100.

[0053] Battery 4 is a power supply installed on the lock 100 side. Battery 4 is, for example, a dry cell battery. Alternatively, instead of battery 4, an AC adapter connected to an external power supply may be provided on the lock 100 to supply the necessary power to the light sources 3a, 3b, sensors 1a, 1b, and unlocking determination unit 8, etc.

[0054] The unlocking determination unit 8 is a processing unit that determines whether the combination of a selected spectrum generation pattern, a spectrum generation pattern generated by the spectrum pattern generation units 2a and 2b, and the structural patterns of the selected sensors 1a and 1b is an expected combination, based on the outputs of sensors 1a and 1b acquired by the control units 5a and 5b. The unlocking determination unit 8 is implemented by a processor (processing circuit) such as a CPU (Central Processing Unit), GPU (Graphic Processing Unit), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field Programmable Gate Array), etc., which reads a program from memory and executes it to realize the function corresponding to each program.

[0055] The unlocking determination process of the unlocking determination unit 8 will be explained using Figures 7 and 8. The unlocking determination unit 8 determines whether the combination of the spectral generation pattern generated by the spectral pattern generation units 2a and 2b and the structural pattern of the sensors 1b and 1a is the expected combination, based on the output of the sensors 1b and 1a when incident light of the spectral pattern generated by the spectral pattern generation units 2a and 2b is incident on them.

[0056] As shown in the upper part of Figure 7, even if the same set of dyes is used for the spectral pattern generation units 2a and 2b, if the mixing ratio of the dyes is different, the spectral patterns generated by the spectral pattern generation units 2a and 2b will be different. For example, as shown in the upper part of Figure 7, if the mixing patterns 60a, 60b, and 60c are patterns with different dye mixing ratios, the spectral pattern 61a generated by mixing pattern 60a, the spectral pattern 61b generated by mixing pattern 60b, and the spectral pattern 61c generated by mixing pattern 60c will be different.

[0057] Furthermore, as shown in the lower part of Figure 7, if the diffraction grating structures of sensors 1a and 1b are different, the current value patterns output by sensors 1a and 1b will also be different. Here, "different diffraction grating structures" means, as mentioned earlier, that at least one of the following is different in the plasmon resonance sensor 1: the pitch 21 (d2) of the irregularities, the ratio of the width of the irregularities (d2 / d1), the height 23 of the protrusions, or the thickness 24 of the metal thin film in the plasmon resonance sensor 1. As shown in the lower part of Figure 7, if the diffraction grating structures 62a, 62b, and 62c have different diffraction structure patterns, the incident light-current pattern 63a output by the plasmon resonance sensor 1 having diffraction grating structure 62a, the incident light-current pattern 63b output by the plasmon resonance sensor 1 having diffraction grating structure 62b, and the incident light-current pattern 63c output by the plasmon resonance sensor 1 having diffraction grating structure 62c will be different. Therefore, the incident light-current pattern output from the plasmon resonance sensor 1 will be as expected only when both the spectral pattern generation unit (dye mixing pattern) and the plasmon resonance sensor 1 are correct. The unlocking determination unit 8 uses this to determine if the lock is unlocked.

[0058] Figure 8 shows the method of unlocking determination performed by the unlocking determination unit 8 in the lock system 300 according to the embodiment. The upper part of Figure 8 shows an example in which both the spectral pattern generation unit (dye mixing pattern) and the diffraction grating structure of the plasmon resonance sensor 1 are correct.

[0059] As previously mentioned, the key system 300 consists of a lock 100 and a key 200 that is detachable from the lock 100 and portable. The lock 100 and the key 200 each have a spectral pattern generating unit and a sensor. Specifically, the lock 100 includes a spectral pattern generating unit 2a realized by a dye in a predetermined mixing ratio and a sensor 1a. The key 200 also includes a spectral pattern generating unit 2b and a sensor 1b. Here, the spectral pattern generating unit 2b is realized by a dye in the same mixing ratio as the spectral pattern generating unit 2a and is identical to the spectral pattern generating unit 2a. The sensor 1b has the same diffraction grating structure as the sensor 1a.

[0060] Here, the unlocking determination unit 8 compares the output result 80a, obtained when the incident light of the spectral pattern generated by the spectral pattern generation unit 2a of the lock 100 is incident on the sensor 1b of the key 200, with the output result 80b, obtained when the incident light of the spectral pattern generated by the spectral pattern generation unit 2b of the key 200 is incident on the sensor 1a of the lock 100, to determine whether the combination of the lock 100 and the key 200 is the expected combination. For example, the unlocking determination unit 8 determines that the combination of the lock 100 and the key 200 is the expected combination if the RSS (root sum of squares) between output result 80a and output result 80b falls below a certain threshold. As another example, the unlocking determination unit 8 determines that the combination of the lock 100 and the key 200 is the expected combination if the RSS between output result 80a and output result 80b falls below a certain threshold. 2 If the coefficient of determination is sufficiently close to 1, it is determined that the combination of lock 100 and key 200 is the expected combination.

[0061] The middle section of Figure 8 shows an example where dyes with different mixing ratios are used in the key 200a. In this case, the unlocking determination unit 8 compares the output result 81a when the incident light of the spectral pattern generated by the spectral pattern generation unit 2a of the lock 100 is incident on the sensor 1b of the key 200a with the output result 81b when the incident light of the spectral pattern generated by the spectral pattern generation unit 70, which is realized with dyes with different mixing ratios, is incident on the sensor 1a of the lock 100 to determine whether the combination of lock 100 and key 200a is the expected combination. Here, since the spectral pattern generation unit 70 of key 200a is realized with dyes with different mixing ratios, the output result 81a is different from the output result 81b. Therefore, the unlocking determination unit 8 determines that the combination of lock 100 and key 200a is not the expected combination.

[0062] The lower part of Figure 8 shows an example where a different diffraction grating structure is used for the key 200b. In this case, the unlocking determination unit 8 compares the output result 82a when the incident light of the spectral pattern generated by the spectral pattern generation unit 2a of the lock 100 is incident on a sensor 71 with a different diffraction grating structure with the output result 82b when the incident light of the spectral pattern generated by the spectral pattern generation unit 2b is incident on the sensor 1a of the lock 100 to determine whether the combination of lock 100 and key 200b is the expected combination. Here, since the sensor 71 of key 200b does not have the expected diffraction grating structure, output result 82a is different from output result 82b. Therefore, the unlocking determination unit 8 determines that the combination of lock 100 and key 200b is not the expected combination.

[0063] The components of the key system 300 according to this embodiment have been described above. Next, the procedure for determining whether the key system 300 is unlocked according to this embodiment will be described using Figure 9.

[0064] First, when the user inserts the key 200 into the lock 100, the power and communication ports 6a and 6b are connected. When a processing circuit (not shown) provided in the lock 100 or key 200 confirms contact with the power and communication ports 6a and 6b (step S100 Yes), the process proceeds to step S200, where power is supplied from the battery 4 to the lock 100 and key 200 through the power and communication ports 6a and 6b, and the electromagnetic shutters 7a and 7b open (step S200). Subsequently, the light sources 3a and 3b light up, sensors 1a and 1b are driven, and a MEMS mechanism (not shown) changes the incident angle to start measuring the current (step S300). Subsequently, the control unit 5a of the lock 100 and the control unit 5b of the key 200 acquire spectral data (step S400). Next, the data acquired by the control unit 5b of the key 200 is transmitted to the unlocking determination unit 8 on the lock 100 side via the power and communication ports 6a and 6b (step S500). Subsequently, the unlocking determination unit 8 determines whether the combination of the spectral generation pattern and the structural pattern of the sensor is the expected combination based on the outputs of sensors 1a and 1b (step S600). As an example, the unlocking determination unit 8 determines whether the combination of the lock 100 and the key 200 is the expected combination by comparing the output result when the incident light of the spectral pattern generated by the spectral pattern generation unit 2b of the lock 100 is incident on the sensor 1b of the key 200 with the output result when the incident light of the spectral pattern generated by the spectral pattern generation unit 2b of the key 200 is incident on the sensor 1a of the lock 100.

[0065] Next, the security performance of the key system 300 according to the embodiment will be described.

[0066] The key system 300 according to this embodiment is a sensor that uses a plasmon resonance sensor 1, which is a near-infrared (NIR) sensor that utilizes the fact that plasmon resonance occurs when light of a specific wavelength is incident on it. In the plasmon resonance sensor 1, there is no simple relationship between the intensity of the incident light and the output current of the plasmon resonance sensor, and the output of the plasmon resonance sensor cannot be easily predicted from the intensity of the incident light, making it difficult to illegally duplicate the key.

[0067] Furthermore, the detailed structure of the diffraction grating structure 22 of the plasmon resonance sensor 1 is difficult to observe with the naked eye. Confirming the detailed diffraction grating structure 22 of the plasmon resonance sensor 1 would require expensive equipment such as an electron microscope, as well as destructive testing. Moreover, even if the diffraction grating structure 22 were known, its fabrication would require expensive machinery such as semiconductor manufacturing equipment, making key duplication practically difficult. Therefore, illegally duplicating the key would be difficult.

[0068] Furthermore, unlike general spectroscopic sensors that do not depend on the sensor structure with respect to wavelength, the output of the diffraction grating type plasmon resonance sensor 1 depends on the pitch of the unevenness of the sensor's diffraction structure, the ratio of the width of the unevenness, the height of the protrusions, the thickness of the gold film, etc. By preparing a large number of these diffraction grating structure patterns, a large number of keys can be prepared.

[0069] On the one hand, the spectrum pattern generation units 2a and 2b in the key system 300 according to the embodiment can easily generate a large number of different spectrum patterns by generating incident light of the spectrum pattern defined for the mixing pattern based on, for example, the mixing pattern selected from the mixing patterns of a plurality of dyes. Considering the spectrum generation pattern (dye mixing pattern) of the key system 300, even if the spectrum after dye mixing is known, it is difficult to accurately calculate the mixing ratio of the dyes unless the spectra of each of the mixed dyes are known. Also, even if the generated spectrum pattern is known, it is considered difficult to actually reproduce that spectrum pattern with a light source, and it can be seen that the key system 300 also has a certain level of security strength on the spectrum pattern generation unit side.

[0070] FIG. 10 shows the theoretical key differences in each element of the key system 300 according to the embodiment. As possible patterns of the diffraction grating structures of the sensors 1a and 1b, there are approximately 10 3 types of patterns for each. Also, as possible spectrum generation patterns of the spectrum pattern generation units 2a and 2b, for example, when using 5 dyes and changing the mixing amount of each dye in about 10 steps, there are approximately 10 5 different patterns for each. Therefore, for the key system 300, the overall theoretical key difference is 10 5 ×10 3 ×10 5 ×10 3 =10 16 (about 1 trillion combinations). For example, considering that the number of key differences of a dimple cylinder lock is about 2.2 trillion combinations, it can be seen that the key system 300 according to the embodiment can ensure a sufficient number of theoretical key differences. Not only the types of the sensors 1a and 1b, but also if the number of dyes used in the dye mixing pattern in the spectrum pattern generation unit increases or the height resolution can be improved, the theoretical key difference will be further improved.

[0071] Furthermore, in the key system 300 according to the embodiment, the lock 100 and key 200 each have a spectral pattern generation unit and a sensor, respectively. The unlocking determination unit 8 determines whether the combination of lock 100 and key 200 is the expected combination by comparing the output result when the incident light of the spectral pattern generated by the spectral pattern generation unit 2a of lock 100 is incident on the sensor 1b of key 200 with the output result when the incident light of the spectral pattern generated by the spectral pattern generation unit 2b of key 200 is incident on the sensor 1a of lock 100. By using this method for unlocking determination, it is not necessary to pre-store information about the correct output data in the processing circuit inside lock 100 or key 200. Unlocking determination can be performed simply by comparing the output results of the sensor 1a of lock 100 and the sensor 1b of key 200, simplifying the design of the unlocking determination unit.

[0072] One possible application of the key system 300 according to this embodiment is a car steering wheel lock. While convenient smart keys are preferred as keys for the car itself, a steering wheel lock could be used to further enhance the car's security, especially in luxury cars. Other applications requiring high security include safe deposit boxes. Furthermore, since the key system 300 according to this embodiment uses electricity to convert analog objects such as dyes and sensor structures into digital objects by generating current, it is a technology well-suited for the security of digital devices such as laptop computers and digital storage devices. Therefore, it can be used in these applications.

[0073] Figure 11 shows the advantages and disadvantages of the key system 300 (NIR Spectrum Lock) according to the embodiment, compared with various types of key systems. The key system 300 (NIR Spectrum Lock) according to the embodiment achieves overwhelmingly high security performance compared to rotary disc cylinder locks, dimple cylinder locks, etc. Smart keys for cars have the advantage of being able to be unlocked without contact, and fingerprint authentication and facial recognition have the convenience of not needing to carry a key, but their security performance is lower compared to the key system 300 according to the embodiment. Furthermore, when quantum computers become practical, the security performance of completely digital locks may dramatically decrease, but since the key system 300 according to the embodiment has an analog structure as a component of the key system 300, it is thought to have a certain level of security resistance even when quantum computers become practical.

[0074] As described above, the key system according to this embodiment can achieve high key performance.

[0075] (Modified version of the embodiment) The embodiments are not limited to the examples described above. As an example of the key system 300 according to the embodiment, the case in which the lock 100 and key 200 have power and communication ports 6a and 6b, respectively, has been described. However, in order to reduce the risk of hacking in the power and communication ports 6a and 6b, the key system 300 according to the embodiment may not have power and communication ports 6a and 6b. In this case, for example, instead of the control unit 5b provided on the key 200 side acquiring the output of the sensor 1b in the key 200, the output of the sensor 1b in the key 200 may be acquired by a new control unit (not shown) provided on the lock 200 side. In this case, for example, reflected light generated as a result of plasmon resonance of light with a predetermined spectral pattern incident on the sensor 1b is guided back to the lock 100 side using a mirror. The reflected light of the sensor 1b guided back to the lock 100 side is measured by an optical sensor (not shown) or further incident on the sensor 1a on the key 200 side. The unlocking determination unit 8 makes an unlocking determination based on the outputs of these sensors.

[0076] Furthermore, although the case in the key system 300 according to the embodiment has been described in which the battery 4 is located only on the lock 100 side, the embodiment is not limited to this, and the battery may also be located on the key 200 side. Also, the unlocking determination unit 8 may be located on the key 200 side instead of the lock 100 side. [Explanation of Symbols]

[0077] 1a...Sensor, 1b...Sensor, 2a...Spectrum pattern generation unit, 2b...Spectrum pattern generation unit, 3a...Light source, 3b...Light source, 8...Unlocking determination unit, 100...Lock, 200...Key

Claims

1. A light source that generates light, A spectral pattern generation unit generates incident light of a spectral pattern defined for a spectral pattern based on a spectral pattern selected from among multiple spectral generation patterns, based on light generated from the light source. A sensor having one structural pattern selected from multiple structural patterns, and which outputs different current values ​​depending on the selected structural pattern when incident light of the spectral pattern is incident on it, An unlocking determination unit determines, based on the output of the sensor when the incident light is incident, whether the combination of the one spectral generation pattern and the one structural pattern of the sensor is an expected combination. A key system equipped with the following features.

2. The key system according to claim 1, wherein the spectral pattern generation unit generates incident light of a spectral pattern defined for a mixed pattern based on a mixed pattern selected from a plurality of dye mixed patterns.

3. The key system according to claim 1, wherein the sensor is a plasmon resonance sensor that generates plasmon resonance when light of a specific wavelength is incident on it, and the plurality of structural patterns are structural patterns in which at least one of the pitch of the irregularities in the plasmon resonance sensor, the ratio of the width of the irregularities, the height of the protrusions, or the thickness of the metal thin film in the plasmon resonance sensor is different.

4. The locking system comprises a lock and a key that is separate from the lock and portable. The lock and the key each have the spectral pattern generation unit and the sensor, The locking determination unit determines whether the combination of the lock and the key is the expected combination by comparing the output result when the incident light of the spectral pattern generated by the spectral pattern generation unit of the lock is incident on the sensor of the key with the output result when the incident light of the spectral pattern generated by the spectral pattern generation unit of the key is incident on the sensor of the lock. The locking determination unit according to claim 1.

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