TWI794696B - Optical sensing device - Google Patents

Abstract

An optical sensing device for biological identification includes a light-emitting module, a light-receiving module, and an identification module. The light-emitting module includes a first light-emitting element that can emit a first light and a second light-emitting element that can emit a second light. The first light and the second light have different wavelengths. The light-receiving module is used for receiving the first light and the second light. The two lights respectively output the first signal and the second signal. The identification module is used to receive the first signal and the second signal and determine whether to output a driving signal.

Description

Optical Sensing Device

An optical sensing device for biometric identification.

In recent years, biosignal detection technology has developed rapidly, including heartbeat detection, blood oxygen detection, face recognition, voice recognition, iris recognition, retina recognition, fingerprint recognition, etc. Among them, face recognition, voice recognition, iris recognition, retina recognition and fingerprint recognition have been widely used in biometric unlocking devices for information and communication products. However, if the biometric unlocking device cannot distinguish the authenticity of the identification object, such as the difference between a real finger and a simulated finger (silicone material), or the difference between a real person's iris and an iris picture, it will cause the biometric unlocking device to fail. function as it should. In view of this, the present invention proposes the following solutions.

An optical sensing device for biometric identification includes a light emitting module, a light receiving module and an identification module. Wherein, the light-emitting module includes a first light-emitting element capable of emitting a first light and a second light-emitting element capable of emitting a second light, the wavelengths of the first light and the second light are different; the light-receiving module is used to receive the first light and the second light The two light beams respectively output the first signal and the second signal; the identification module is used for receiving the first signal and the second signal and judging whether to output a driving signal.

FIG. 1 shows a schematic diagram of the connection between an optical sensing switch device 1 and a sensing device 2 according to an embodiment of the present invention. Please refer to Figure 1, there is a signal channel 13a connected between the optical sensing switch device 1 and the sensing device 2, the optical sensing switch device 1 includes a light emitting module 11, a light receiving module 12, and an identification module 13 and a signal channel 12a to connect the light receiving module 12 and the identification module 13. The light emitting module 11 includes at least a first light emitting element 11a and a second light emitting element 11b. The first light emitting element 11a can emit a first light L1, and the second light emitting element 11b can emit a second light L2. The first light L1 and the second light L2 have different wavelengths and have fixed or variable energy. After irradiating the object 4 to be tested, a first reflected light L1' and a second reflected light L2' are respectively formed. Wherein, in one embodiment, both the first light emitting element 11a and the second light emitting element 11b are directional light sources, so the first light L1, the second light L2, the first reflected light L1' and the second reflected light L2' are all It is in the form of a beam, so as to facilitate the optical design of the optical sensing switch device 1 . After the first reflected light L1' and the second reflected light L2' enter the light-receiving module 12, they are converted into a first signal and a second signal by the light-receiving module 12, and are respectively transmitted to the identification module through the signal channel 12a 13. The identification module 13 then determines whether the object 4 to be detected is a preset biological tissue to determine whether to drive the sensing device 2 .

FIG. 2 shows a judgment flow chart of the identification module 13 disclosed according to an embodiment of the present application. Referring to Figures 1 and 2, first, the identification module 13 receives the first signal and the second signal; then, divides the power of the first signal and the second signal to obtain an energy ratio; judges whether the energy ratio falls into the preset If the energy ratio falls within the preset value range, the identification module 13 outputs a drive signal to drive the sensing device 2; if the energy ratio does not fall within the preset value range, the identification module 13 does not output the drive signal signal.

In one embodiment, when the object 4 to be measured is a biological tissue, such as the skin of the finger 4a shown in Figure 3 and the iris of the eye 4b shown in Figure 4, if the first light L1 and the second light L2 uses UV light with strong energy, which will cause damage to biological tissues; therefore, the first light L1 and the second light L2 are preferably light with a peak wavelength (W _p ) greater than 420nm; in one embodiment, the second light L1 An infrared light with a wavelength between 1000nm and 1100nm can be selected for the first light L1, and an infrared light with a wavelength between 1400nm and 1600nm can be selected for the second light L2.

Figure 5 shows the changes in the light absorption rate of various human subcutaneous tissue components in Figure 3. Light with a wavelength between 500nm and 1800nm is effective for glucose (Glucose), water (H2O), protein (Protein), lipid (Lipid), oxygenated hemoglobin (Oxydative Hemoglobin, HbO ₂ ) and heme ( Hemoglobin, Hb), which have different absorption ratios in different wavelength ranges. Taking human skin as an example, the proportions of water (H2O), protein (Protein), lipid (Lipid), oxydative hemoglobin (HbO ₂ ) and hemoglobin (Hb) are roughly fixed, so the wavelength The different first light L1 and second light L2 will be absorbed by the skin according to a certain proportion after being incident on the skin to generate the first reflected light L1' and the second reflected light L2'. By dividing the power value of the first reflected light L1' and the power value of the second reflected light L2', a specific energy ratio range belonging to the skin can be obtained. Since the composition of the iris is different from that of the skin, the range of energy ratios belonging to the iris will be different from that of the skin.

In one embodiment, the light receiving module 12 includes a photodiode, which can convert the first reflected light L1' and the second reflected light L2' into electrical energy, so the first signal and the second signal are in the form of Including electric energy; through the signal channel 12a, the first signal and the second signal are respectively transmitted to the identification module 13, and the identification module 13 calculates the power value (Watt) of the first signal and the second signal, and the first signal and the second signal The power value of the second signal is divided to obtain the energy ratio; then, the identification module 13 compares the energy ratio with the preset value range to determine whether to output a drive signal; when the energy ratio falls within the preset value range , the identification module 13 will output a driving signal through the signal channel 13a to drive the sensing device 2 to make the sensing device 2 actuate; when the energy ratio does not fall within the numerical range, the identification module 13 will not output the driving signal , the sensing device 2 will not act at this time. In this embodiment, the signal channel 12a and the signal channel 13a include wired or wireless forms. In another embodiment, when the optical sensing switch device 1 and the sensing device 2 are installed in a smart electronic device, such as a mobile phone, a smart watch, an access control device, etc., the smart electronic device can actively drive the identification module 13 to send out a signal to drive the light-emitting module 11 through the signal channel 12 to carry out the above identification procedure.

In one embodiment, the optical sensing switch device 1 is used to determine whether the object under test is skin. The first light-emitting element 11a and the second light-emitting element 11b are infrared light elements capable of emitting peak wavelengths (Peak Wavelength; W _p ) of 1150nm and 1400nm respectively, providing specific energy to the first light-emitting element 11a and the second light-emitting element 11b respectively, For example, 10mW and 4mW; then, the first light-emitting element 11a and the second light-emitting element 11b emit the first light L1 and the second light L2 of the beam pattern and enter the human skin tissue (the object 4 to be tested), and then reflect and emit the beam pattern The first reflected light L1 ′ and the second reflected light L2 ′, and then, the first reflected light L1 ′ and the second reflected light L2 ′ are absorbed by the light receiving module 12 and converted into a first signal and a second signal. Since human skin tissue contains water, glucose, protein, hemoglobin and other components, the first signal and the second signal are then transmitted to the identification module 13, and the power value of the first signal measured by the identification module 13 is 3.26mW and The power value of the second signal is 0.5mW; the preset value range of the identification module 13 is between 6.4 and 6.7, corresponding to the human skin tissue and the fixed electric energy input to the first light-emitting element 11a and the second light-emitting element 11b, 10mW and 4mW; the identification module 13 calculates the power value of the first signal and the power value of the second signal (3.26mW /0.5mW), and obtains an energy ratio of 6.54, which falls within the built-in value range of 6.4~6.7 Therefore, the recognition module 13 judges that the object 4 to be detected is human skin tissue, and then sends a driving signal to the sensing device 2 to drive the sensing device 2 . In this embodiment, if the object 4 to be measured is a material with a reflectivity greater than 50% for the first light L1 and the second light L2, such as metal, reflective plastic, etc., the first light L1 and the second light L2 are emitted After entering the metal surface, the power values of the first signal and the second signal are 5mW and 2mW respectively. After calculation, the energy ratio (5mW/2mW) is 2.5, which does not fall within the value range of 6.4~6.7 built in the identification module 13. Therefore, the recognition module 13 judges that the object 4 to be tested is not a human skin tissue, and does not send a driving signal to the sensing device 2, and the sensing device 2 does not act at this time.

In the above embodiments, the light emitting module 11 includes the first light emitting element 11a and the second light emitting element 11b is only an example, in other embodiments, the light emitting module 11 includes more than two light emitting elements that emit light of different wavelengths, for example, two light emitting elements Pole (Light Emitting Diode, LED); the light receiving module 12 includes a photodiode (Photodiode), a photoelectric conversion element that can convert light into a current or voltage signal; the first light emitting element 11a, the second light emitting element 11b And the light-receiving module 12 is arranged on a circuit board 14, wherein the circuit board 14 includes a printed circuit board (Printing Circuit Board, PCB); a protective cover 15 covers the light-emitting module 11 and the light-receiving module 12, and the protective cover 15 includes a lens 161, a lens 162, and a lens 163 respectively corresponding to the first light emitting element 11a, the second light emitting element 11b, and the light receiving module 12, wherein the lens 161 and the lens 162 respectively allow the first light L1 and the second light L2 to pass through, and the lens 163 allows the first reflected light L1' and the second reflected light L2' to pass through. Among them, the lens 161, the lens 162 and the lens 163 can be used to protect the first light-emitting element 11a, the second light-emitting element 11b and the light-receiving module 12; in another embodiment, the lens 161, the lens 162 and the lens 163 can also adjust the first The traveling directions of light beams such as the first light L1, the second light L2, the first reflected light L1' and the second reflected light L2' are to ensure that the receiving module 12 receives the maximum amount of light without being disturbed by noise. Except for the lens 161, the lens 162 and the lens 163, the rest of the protective cover 15 is made of opaque materials, such as metal, black plastic, wood, etc., so as to prevent external light from entering the light-receiving module 12 and causing noise, so that The identification module 13 misjudged.

The identification module 13 includes an Application Specific Integrated Circuit (ASIC), which can receive the first signal and the second signal transmitted by the light receiving module 12, and measure the power value of the first signal and the second signal , calculating the energy ratio, judging whether the energy ratio falls within a built-in value range, and determining whether to output a driving signal.

1: Optical sensing switch device 11: Lighting module 11a: the first light emitting element 11b: the second light-emitting element 12: Light receiving module 12a: Signal channel 13: Identification module 13a: Signal channel 14: Circuit board 15: Protective cover 161: lens 162: lens 163: lens 2: Sensing device 3: Changes in light absorption rate of biological tissue components 4: Object to be measured 4a: Finger 4b: eyes L1: first ray L2: second ray L1': the first reflected light L2': second reflected light

Figure 1 shows a schematic diagram of an optical sensing switch device and a sensing device;

Fig. 2 shows the judgment flow chart of the identification module;

Figure 3 shows an optical sensing switch device and an object to be measured according to an embodiment;

Figure 4 shows an optical sensing switch device and an object to be measured according to an embodiment;

Fig. 5 shows the change graph of the light absorptivity of various biological tissue components.

1: Optical sensing switch device

11: Lighting module

11a: the first light emitting element

11b: the second light-emitting element

12: Light receiving module

12a: Signal channel

13: Identification module

13a: Signal channel

14: Circuit board

15: Protective cover

161: lens

162: lens

163: lens

2: Sensing device

L1: first ray

L2: second ray

L1': the first reflected light

L2': second reflected light

Claims (8)

A biometric identification device, comprising: a light-emitting module, including a first light-emitting element capable of emitting a first light and a second light-emitting element capable of emitting a second light, wherein the wavelength of the first light is the same as that of the second light different; a light-receiving module, used to receive the first light and the second light, respectively output a first signal and a second signal; and an identification module, to receive the first signal and the second signal; Wherein, the identification module judges whether an object to be tested is a preset biological tissue by the first signal and the second signal to determine to output a driving signal; wherein, the first signal and the second signal have an energy Ratio, the identification module judges whether the energy ratio falls within a preset value range to determine whether to output the drive signal, wherein the first light-emitting element and the second light-emitting element are directional light sources, the first Both the light and the second light are beam types. The device according to claim 1, wherein the identification module comprises an application specific integrated circuit (ASIC). The device according to claim 1, wherein the first light emitting element or the second light emitting element comprises a light emitting diode (LED). The device according to claim 1, wherein the first light or the second light comprises infrared light. The device according to claim 1, wherein the light receiving module includes a photodiode. The device according to claim 1 further includes a circuit board, and the light emitting module, the light receiving module and the identification module are arranged on the circuit board. The device according to claim 1 further includes a protective cover covering the light-emitting module and the light-receiving module, wherein the protective cover includes a plurality of holes respectively corresponding to the light-emitting module and the light-receiving module. The device according to claim 1, wherein the recognition module includes a fingerprint recognition module, a face recognition module or a blood oxygen detector.

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