JP2021012119A - Infra-red ray measurement device, and infra-red ray measurement method - Google Patents

Abstract

To provide an infra-red ray measurement device and an infra-red measurement method that, when measuring infra-red reflection light by a proximity measurement, prevent ambient light from being included as noise by a relatively simple measurement and can suppress wrong actions.SOLUTION: An infrared ray measurement device 100 comprises: an infrared light emitting diode 420; a proximity measurement unit 50 that serves as a measurement unit; a PS control logic 18; and a micro control unit (MCU) 44. The PS control logic 18 is configured to control a drive of the infrared light emitting diode 420 and proximity measurement unit 50 at a prescribed timing based on a fluctuation cycle measured by the proximity measurement unit 50. The proximity measurement unit 50 is configured to output a first measurement value measuring infrared reflection light in which an infrared ray is reflected upon a proximity object at the prescribed timing, a second measurement value and a third measurement value measured at a time before and after a measurement time of the first measurement value in a state where the infrared light emitting diode 420 does not emit light. The MCU 44 is configured to subtract an average of the second measurement value and the third measurement value from the first measurement time, and calculate infrared reflection light illuminance.SELECTED DRAWING: Figure 1

Description

The present invention relates to an infrared measuring device capable of measuring infrared rays irradiated to a nearby object, and a measuring method thereof.

Devices provided with a display device that employs a touch panel method (for example, mobile phones, smartphones, PDAs (Personal Digital Assistants), etc.) may malfunction when a part of the human body comes into contact with the touch panel. In particular, with smartphones, it is necessary to bring the ears, face, etc. into contact with the touch panel when making a telephone call, and in order to prevent malfunctions due to the touch panel due to contact with the ears, face, etc., the display on the display device is turned off. It is necessary to disable the operation on the touch panel.

In order to invalidate the operation on the touch panel, an infrared measuring device is adopted as a measuring device for detecting that an ear, a face, or the like approaches the touch panel. The infrared measuring device is an optical proximity sensor (hereinafter, also simply referred to as a proximity sensor) that detects that an object (for example, an ear, a face, etc.) has approached a device by measuring infrared rays radiated to a nearby object. Is.

The proximity sensor detects a proximity object by emitting a pulse of an infrared LED and measuring the reflected light from the object using a photodiode having a sensitivity peak in the infrared region. However, when measuring a nearby object with a proximity sensor, an error may occur in the measurement due to the influence of ambient light including infrared components such as sunlight, incandescent lamp, and halogen light. Therefore, when measuring a proximity object with a proximity sensor, a proximity sensor capable of suppressing the influence of ambient light has been developed (Patent Document 1).

Japanese Unexamined Patent Publication No. 2010-185851

Since the proximity sensor shown in Patent Document 1 measures and calculates the change time of the photodiode and compares it with the threshold value, measurement data of ambient light is required. However, when an incandescent lamp, a halogen lamp, a fluorescent lamp, an LED light source, or the like is used as ambient light, the brightness of the ambient light fluctuates (flickers) at a frequency of 50/60 Hz of a commercial power source.

When the ambient light fluctuates, the proximity sensor changes the brightness of the ambient light depending on the timing of measuring the ambient light and the timing of measuring the reflected light from the object, so the change in the brightness of the ambient light is the noise. Measured as. Therefore, in the proximity sensor, the change in ambient light is added as noise, and the reflected light from the object cannot be measured accurately.

The present invention was devised to solve the above-mentioned problems, and when infrared reflected light is measured by proximity measurement, it is possible to prevent ambient light from being included as noise by a relatively simple measurement. It is an object of the present invention to provide an infrared measuring device capable of suppressing malfunction, and a measuring method thereof.

According to a certain embodiment, an infrared light emitting element that irradiates a nearby object with infrared rays, an infrared reflected light reflected by the nearby object while the infrared light emitting element is emitting light, or a state in which the infrared light emitting element is non-emission From the measuring unit that measures the ambient light in, the infrared light emitting element at a predetermined timing based on the fluctuation cycle of the ambient light measured by the measuring unit, the control unit that controls the drive of the measuring unit, and the measuring unit. The first measurement is provided with an arithmetic processing unit having a means for arithmetically processing the measurement data and calculating the infrared reflected light illuminance, and the measuring unit measures the infrared reflected light reflected by an infrared object at a predetermined timing. The value and the second measured value and the third measured value measured at the time before and after the measurement time of the first measured value in the non-infrared state are output, and the arithmetic processing unit outputs the value and the third measured value. The infrared reflected light illuminance is calculated by subtracting the average of the second measured value and the third measured value from the measured value of 1.

Preferably, the measuring circuit for measuring the infrared light of the measuring unit shares the circuit with the measuring circuit for measuring the fluctuation period.

Preferably, the control unit controls the measuring unit to measure the infrared reflected light by setting a predetermined timing as the timing when the peak of the fluctuation cycle is removed.

Preferably, the control unit controls the measurement unit to measure the infrared reflected light by setting the timing when the peak of the fluctuation cycle is deviated as the timing deviating from the peak of the fluctuation period by 1/4 period.

Preferably, the measuring unit outputs the first measured value, the second measured value, and the third measured value twice with the predetermined timing as the timing of 1/2 of the fluctuation cycle, and the arithmetic processing unit has 2 Each infrared reflected light illuminance is obtained from the measured values output twice, and the average of the infrared reflected light illuminance obtained twice is calculated.

Preferably, the control unit has a predetermined timing such that the first waiting time until the measurement of the measuring unit is started and the second waiting time from the first waiting time to the next measurement. The measuring unit is controlled to measure the infrared reflected light.

Preferably, the control unit measures the ambient light with the measurement unit at a predetermined cycle to update the fluctuation cycle.

Preferably, the light receiving element that receives the infrared light of the measuring unit shares the light receiving element and the element for measuring the fluctuation period.

According to a certain embodiment, an infrared light emitting element that irradiates a nearby object with infrared rays, an infrared reflected light reflected by the nearby object while the infrared light emitting element is emitting light, or a state in which the infrared light emitting element is non-emission. From the measuring unit that measures the ambient light in, the infrared light emitting element at a predetermined timing based on the fluctuation cycle of the ambient light measured by the measuring unit, the control unit that controls the drive of the measuring unit, and the measuring unit. This is a measurement method in which infrared reflected light is measured by an infrared measuring device including an arithmetic processing unit having a means for calculating the infrared reflected light illuminance by arithmetically processing the measurement data, and the infrared light emitting element does not emit light in the measuring unit. A step of measuring the ambient light in the state of, a step of calculating a predetermined timing based on the fluctuation cycle measured by the measuring unit, and an infrared reflected light in which infrared rays are reflected by a nearby object at a predetermined timing in the measuring unit. The first measured value measured in the above, and the second measured value and the third measured value measured at times before and after the measurement time of the first measured value in a non-light emitting state are output. This includes a step and a step of calculating the infrared reflected light illuminance by subtracting the average of the second measured value and the third measured value from the first measured value in the arithmetic processing unit.

In the infrared measuring device according to a certain embodiment, it is possible to prevent ambient light from being included as noise and suppress malfunction by measuring at a predetermined timing based on a fluctuation cycle.

It is a figure which shows the whole structure of the infrared ray measuring apparatus which concerns on this Embodiment 1. It is a figure for demonstrating the measurement timing of the infrared measuring apparatus which concerns on Embodiment 1. It is a figure for demonstrating the measurement timing of ambient light and reflected light in the infrared measuring apparatus which concerns on Embodiment 1. It is a flowchart for demonstrating the measurement by the infrared measuring apparatus which concerns on Embodiment 1. It is a figure for demonstrating the measurement timing of ambient light and reflected light in the infrared measuring apparatus which concerns on Embodiment 2. It is a flowchart for demonstrating the measurement by the infrared measuring apparatus which concerns on Embodiment 2. It is a figure for demonstrating the timing of two measurements by the infrared measuring apparatus which concerns on Embodiment 3. It is a figure for demonstrating the measurement timing of ambient light and reflected light in the infrared measuring apparatus which concerns on Embodiment 3. It is a flowchart for demonstrating the measurement by the infrared measuring apparatus which concerns on Embodiment 3. It is a figure for demonstrating the measurement timing of ambient light and reflected light in the infrared measuring apparatus which concerns on Embodiment 4. It is a flowchart for demonstrating the measurement by the infrared measuring apparatus which concerns on Embodiment 4. It is a block diagram which shows the structure of the infrared measuring apparatus which concerns on a modification. It is a figure which shows the structure of the light receiving element of the infrared measuring apparatus which concerns on a modification.

Hereinafter, the infrared measuring device according to the embodiment of the present invention will be described in detail with reference to the drawings. In the figure, the same reference numerals indicate the same or corresponding parts.

(Embodiment 1)
The infrared measuring device according to the first embodiment will be described below by taking as an example an optical proximity sensor that detects that an object has approached the device by measuring infrared rays radiated to a nearby object. However, the present invention is not limited to this, and any infrared measuring device may be used as long as it is an infrared measuring device that measures infrared rays with a configuration similar to that of a proximity sensor.

FIG. 1 is a diagram showing an overall configuration of the infrared measuring device 100 according to the first embodiment. Infrared measuring device 100, the proximity measurement unit 50, and a register circuit 14, PS interface 15, POR (power on reset) 16, ^{I 2} C interface 17 and the like. Here, the POR 16 initializes the IC when the power is turned on.

Further, the infrared measuring device 100 includes an MCU (micro control unit) 44, an infrared light emitting diode (infrared light emitting element) 420, and the like, which are arithmetic processing units. The MCU 44 is an external control unit, and switches the proximity measurement unit 50 on and off. The infrared measuring device 100 is also provided with a GND terminal for LEDs, a GND terminal for circuit elements, and the like. A capacitor 430 is inserted between the power supply voltage VDD terminal and the GND, thereby cutting high frequency noise.

The proximity measurement unit 50 includes an LED pulse generator 1, an infrared LED driver 2, a light receiving element 3a for flicker measurement, a light receiving element 3b for proximity measurement, an integrating circuit 4, an AD converter 5, a logarithmic converter 6, and a PS control logic. It is composed of 18. The PS control logic 18 is a logic circuit for controlling the proximity measurement unit 50. Further, the PS control logic 18 performs processing such as calculation and determination based on the digital data from the AD converter 5 and the register circuit 14. The cathode of the infrared light emitting diode 420 to which the power supply voltage VDD is supplied is connected to the terminal of the ILED. The infrared light emitting diode 420 is a diode that emits light in the infrared region.

The light receiving element 3a for flicker measurement is composed of a photodiode having an infrared cut filter F1 on the light receiving surface that transmits visible light and ultraviolet rays in order to detect visible light with high sensitivity. Further, the light receiving element 3a may be composed of a photodiode having a sensitivity peak in the visible light region. The light receiving element 3b for proximity measurement is composed of a photodiode having a visible light cut filter F2 on the light receiving surface, which cuts visible light and ultraviolet rays and transmits infrared rays in order to detect infrared rays with high sensitivity. Further, the light receiving element 3b may be composed of a photodiode having a sensitivity peak in the infrared region. The light receiving element 3a and the light receiving element 3b are connected in series with the integrator circuit 4. The light receiving element 3a is connected to the integrating circuit 4 via the switch SW1, and the light receiving element 3b is connected to the integrating circuit 4 via the switch SW2. Therefore, by switching the switch SW1 and the switch SW2, it is possible to switch whether the signal input to the integrating circuit 4 is a signal from the light receiving element 3a for flicker measurement or a signal from the light receiving element 3b for proximity measurement. be able to.

The measurement of infrared reflected light by proximity measurement is performed as follows. First, the LED pulse generator 1 generates a pulse that is a basis for causing the infrared light emitting diode 420 to emit light, and supplies this to the infrared LED driver 2. The infrared LED driver 2 changes the pulse signal for driving the infrared light emitting diode 420 based on the pulse signal from the LED pulse generator 1. Since the infrared light emitting diode 420 is current driven, the pulse signal output from the infrared LED driver 2 is a current pulse signal. The infrared LED driver 2 can create a current pulse signal from 5 mA to 200 mA, and uses, for example, a current pulse signal in the range of 5 mA to 10 mA. The duty ratio of the current pulse signal can be changed in various ways, and the light emission period can be, for example, 250 μS.

In this way, when the driving current pulse signal of the light emitting diode is supplied from the infrared LED driver 2 to the infrared light emitting diode 420, the infrared light emitting diode 420 performs a light emitting operation during the on period of the driving current pulse signal. Repeat this. When the proximity measurement unit 50 is measuring the ambient light, the infrared light emitting diode 420 is not emitted. This is to prevent the light received from the infrared light emitting diode 420 from becoming an error signal for the measurement of ambient light.

The infrared rays emitted from the infrared light emitting diode 420 reach the proximity object (object) 40 and are reflected. The infrared reflected light reflected from the proximity object 400 and returned is received by the light receiving element 3b for proximity measurement. That is, the light receiving element 3b is connected to the integrator circuit 4 by turning off the switch SW1 and turning on the switch SW2. Further, the ambient light measured before and after the measurement of the infrared reflected light is received by the light receiving element 3a for flicker measurement, and is measured by the proximity measurement unit 50. That is, the proximity measurement unit 50 functions as a flicker measurement unit, and connects the light receiving element 3a to the integration circuit 4 by turning on the switch SW1 and turning off the switch SW2. The infrared reflected light is converted into a photocurrent by the light receiving element 3b and output to the integrating circuit 4. In the integrator circuit 4, the photocurrent is integrated by an integrator circuit consisting of an amplifier and a capacitor, and the value is output to the AD converter 5.

The AD converter 5 AD-converts the value integrated by the integrator circuit 4 and outputs it as a digital value. Here, the integrator circuit 4 and the AD converter 5 constitute an integrator type AD conversion circuit. In the integrated AD conversion circuit, the value of the optical current is integrated and amplified by repeating the charging of the electric charge to the capacitor by the optical current and the batch discharge or the stepwise discharge of the electric charge from the capacitor, and the amplified value is digitally generated. Converting to a value.

The output of the AD converter 5 is input to the logarithmic converter 6 and converted into a logarithm. The logarithmic converter 6 converts, for example, 21-bit input data into 8-bit logarithmic data and outputs the data. The logarithmic data from the logarithmic converter 6 is input to and held in the register circuit 14. Digital data held in the register circuit 14 is output to MCU44 via the ^{I 2} C interface 17. On the other hand, when proximity measurement is performed and proximity is detected, an interrupt signal is transmitted to the MCU 44 via the PS interface 15.

The illuminance measurement of the ambient light is also performed by the proximity measurement unit 50. When the light from the ambient light light source 41 is received by the light receiving element 3a, a photocurrent is generated in the light receiving element 3a due to the photoelectric conversion action. This photocurrent is integrated by the integrator circuit 4 consisting of an amplifier and a capacitor, and the value is input to the AD converter 5. The digital value AD-converted by the AD converter 5 is transmitted to the logarithmic converter 6. In the logarithmic converter 6, the digital value is converted into logarithmic data and transmitted to the register circuit 14, and the transmitted logarithmic data is held in the register circuit 14. Ambient light measurement data stored in the register circuit 14 is output to MCU44 via the ^{I 2} C interface 17.

In the infrared measuring device 100, the flicker measurement is performed by repeatedly performing ambient light measurement (measurement without light emission) using the circuit of the proximity measuring unit 50, instead of simply adding the flicker sensor as it is as described above. In the infrared measuring device 100, the circuit for flicker measurement and the circuit for proximity measurement are not provided separately, but only one circuit is provided, and the circuits can be shared. That is, in the infrared measuring device 100, it can be considered that the sequence is changed so that the ambient light measurement can be measured by the proximity sensor, rather than simply combining the flicker sensor and the proximity sensor.

Next, the basic measurement timing in the proximity measurement of the infrared measuring device 100 will be described. FIG. 2 is a diagram for explaining the measurement timing of the infrared measuring device 100 according to the first embodiment. In FIG. 2A, the horizontal axis represents time. Since the ambient light includes light from a light source such as incandescent light or halogen light whose emission intensity fluctuates at a predetermined cycle based on the commercial power frequency (50 Hz, 60 Hz), the irradiance of the ambient light also fluctuates. ..

Therefore, the infrared measuring device 100 measures the infrared component of the ambient light before and after the infrared light emitting diode 420 is made to emit light and the reflected light from the object is measured, and the average of these values is red from the object. The infrared component of ambient light can be removed by subtracting from the measured value of externally reflected light.

As shown in FIG. 2A, when the infrared measuring device 100 emits the infrared light emitting diode 420 to measure the infrared reflected light (reflected light measurement), the infrared light emitting diode 420 is not emitted before and after this. Measure the ambient light (ambient light measurement) with. Let B be the measured value in the reflected light measurement, and let A1 and A3 be the measured values of the ambient light before and after this, respectively. As shown in FIG. 2B, not only the infrared reflected light component but also the ambient light component at this time is superimposed on the measured value B. Therefore, in order to obtain the component of infrared reflected light, it is necessary to subtract the component of ambient light from the measured value B. Assuming that the ambient light component is equal to the average value of the ambient light measurement value A1 and the measured value A2 before and after the reflected light measurement, the infrared reflected light component is calculated by B- (A1 + A2) / 2. it can. The component of this infrared reflected light becomes the output value from the infrared measuring device 100.

Here, the measured values A1 and A2 of the ambient light are calculated by the proximity measuring unit 50 as the irradiance based on the light current from the light receiving element 3a, and the measured value B of the infrared reflected light is calculated by the proximity measuring unit 50. It is calculated as the irradiance based on the light current from the light receiving element 3b. That is, as shown in FIG. 2B, the light from the light source 41 is received by the light receiving element 3a, and the irradiance based on the light current from the light receiving element 3a is the measured values A1 and A2 of the ambient light. The infrared light emitting diode 420 is made to emit light, the reflected light from the proximity object 400 and the light from the light source 41 are received by the light receiving element 3b, and the radiated illuminance based on the light current from the light receiving element 3b is the measurement of the infrared reflected light. The value is B. The light receiving element 3a, the light receiving element 3b, and the infrared light emitting diode 420 are controlled by the same proximity measurement unit 50.

However, in the method of calculating the component of the infrared reflected light as described above, the influence of the ambient light fluctuation may become large depending on the measurement timing. FIG. 3 is a diagram for explaining the measurement timing of the ambient light and the reflected light in the infrared measuring device 100 according to the first embodiment. In FIG. 3, black circles (hatched circles in the figure, the same applies hereinafter) indicate infrared reflected light measurement timings, and white circles indicate ambient light measurement timings. As shown in FIG. 3A, when the measurement of the infrared reflected light is the measurement timing A at which the irradiance of the ambient light peaks, the ambient light component is the ambient light before and after the measurement of the infrared reflected light. It becomes larger than the measured value of. That is, at the measurement timing A, the influence of ambient light fluctuation becomes large. Therefore, even if the average value of the measured value A1 and the measured value A2 of the ambient light is subtracted from the measured value B of the infrared reflected light, the influence of the ambient light fluctuation cannot be completely removed from the measured value B.

On the other hand, as shown in FIG. 3A, when the measurement of the infrared reflected light is the measurement timing B in which the peak of the irradiance of the ambient light is removed, the components of the ambient light are before and after the measurement of the infrared reflected light. It is almost the middle value of the measured value of the ambient light. That is, at the measurement timing B, the influence of ambient light fluctuation becomes small. Therefore, by subtracting the average value of the measured value A1 and the measured value A2 of the ambient light from the measured value B of the infrared reflected light, the influence of the ambient light fluctuation can be substantially removed from the measured value B.

In the method of calculating the component of infrared reflected light in this way, the component of ambient light may not be removed depending on the measurement timing, and the component may remain, and infrared reflection in which the component of ambient light is added as noise. The irradiance of light is calculated. If a component of ambient light is added as noise to the calculated irradiance of infrared reflected light, it causes a malfunction of the infrared measuring device such as determination that a nearby object exists even if there is no nearby object.

In order to solve the above-mentioned problem, as shown in FIG. 3B, the ambient light is measured by the light receiving element 3a to grasp the ambient light fluctuation, and then the peak of the ambient light fluctuation cycle is removed. It is necessary to control the proximity measuring unit 50 to measure the infrared reflected light. In FIG. 3B, a peak having a large measured value is defined as + P and a peak having a small measured value is defined as −P in the fluctuation period of ambient light. Then, for example, the MCU 44 has a period T1 from the peak of + P to the peak of −P, a period T2 from the peak of −P to the peak of + P, and a period of 1/4 of the fluctuation period (T1 + T2) of the ambient light. 1/4 period) is calculated. The PS control logic 18 controls the proximity measurement unit 50 with a timing that is 1/4 of the peak of the fluctuation cycle of the ambient light as the measurement timing.

Next, the measurement by the infrared measuring device 100 according to the first embodiment will be described with reference to the flowchart. FIG. 4 is a flowchart for explaining the measurement by the infrared measuring device 100 according to the first embodiment. First, the infrared measuring device 100 continuously measures the ambient light with the light receiving element 3a (step S10).

The infrared measuring device 100 detects the fluctuation cycle of the ambient light from the result obtained by continuous measurement in step S10, and determines whether or not the phase of the fluctuation cycle can be grasped (step S11). Specifically, the infrared measuring device 100 detects the fluctuation cycle of the ambient light (T1 + T2) as shown in FIG. 3B, and the fluctuation cycle is known at which timing of the fluctuation cycle of the ambient light. Grasp the phase of. When the phase of the fluctuation period cannot be grasped (NO in step S11), the infrared measuring device 100 returns the process to step S10 and continues the continuous measurement of ambient light.

When the phase of the fluctuation period can be grasped (YES in step S11), the infrared measuring device 100 calculates the measurement timing of the infrared reflected light based on the grasped phase (step S12). Specifically, as shown in FIG. 3B, the infrared measuring device 100 calculates the timing out of the peak of the fluctuation cycle of the ambient light by a period of 1/4 as the measurement timing. The measurement timing is not limited to the timing that deviates from the peak of the ambient light fluctuation cycle by a period of 1/4, and the timing that is less affected by the ambient light fluctuation (for example, the timing that deviates from the peak of the ambient light fluctuation cycle). ). If the fluctuation period and phase of the ambient light cannot be grasped, the infrared measuring device 100 determines that the ambient light has no flicker component, and measures the infrared reflected light at the normal measurement timing (default timing). May be good.

The infrared measuring device 100 measures the infrared reflected light at the measurement timing calculated in step S12 (step S13). The infrared measuring device 100 measures the infrared reflected light at the timing of the black circle shown in FIG. 3 (b).

The infrared measuring device 100 calculates the infrared reflected light illuminance from the difference from the average value of the ambient light before and after the measured infrared reflected light (step S14). The infrared measuring device 100 obtains an average value from the measured values of the ambient light of the white circles before and after the black circle shown in FIG. 3B, and subtracts the average value from the measured value of the infrared reflected light of the black circle. As a result, the infrared measuring device 100 can obtain the infrared reflected light illuminance substantially excluding the influence of ambient light fluctuation.

As described above, the infrared measuring device 100 according to the first embodiment is an infrared light emitting diode 420, a proximity measuring unit 50 which is a measuring unit, a PS control logic 18 which is a control unit, and an arithmetic processing unit. It is equipped with an MCU44. The infrared light emitting diode 420 irradiates a nearby object with infrared rays. The proximity measurement unit 50 measures the infrared reflected light reflected by a nearby object while the infrared light emitting diode 420 is emitting light, or the ambient light when the infrared light emitting diode 420 is not emitting light. The PS control logic 18 controls the driving of the infrared light emitting diode 420 and the proximity measurement unit 50 at a predetermined timing based on the fluctuation cycle of the ambient light measured by the proximity measurement unit 50. The MCU 44 has a means for calculating the infrared reflected light illuminance by arithmetically processing the measurement data from the proximity measurement unit 50. The proximity measurement unit 50 measures the first measured value in which infrared rays are reflected by a nearby object at a predetermined timing, and the measurement time of the first measured value in a state where the infrared light emitting diode 420 does not emit light. The second measured value and the third measured value measured at the time before and after the above are output. The MCU 44 calculates the infrared reflected light illuminance by subtracting the average of the second measured value and the third measured value from the first measured value.

The infrared measuring device 100 according to the first embodiment mitigates the influence of ambient light fluctuation by measuring at a predetermined timing based on the fluctuation cycle, prevents ambient light from being included as noise, and suppresses malfunction. can do.

The measurement circuit for measuring the infrared light of the proximity measurement unit 50 may share the circuit with the measurement circuit for measuring the fluctuation period. As a result, it is not necessary to separately receive a measurement circuit for measuring the fluctuation cycle, and the cost of the infrared measuring device 100 can be reduced. Further, by sharing the measurement circuit for measuring infrared light and the measurement circuit for measuring the fluctuation cycle, the phase of the fluctuation cycle of ambient light can be grasped, and the infrared measuring device 100 can perform infrared rays at an appropriate timing. The reflected light can be measured. In the infrared measuring device 100 shown in FIG. 1, an example in which a measuring circuit for measuring infrared light and a measuring circuit for measuring a fluctuation cycle are shared is shown, but a measurement circuit is separately provided to provide a fluctuation cycle. It may be synchronized so that the phase can be grasped.

The PS control logic 18 may control the proximity measurement unit 50 to measure the infrared reflected light by setting a predetermined timing as the timing when the peak of the fluctuation cycle is removed. In particular, it is preferable that the timing off the peak of the fluctuation period is a timing off by a quarter period from the peak of the fluctuation cycle. As a result, the infrared measuring device 100 can mitigate the influence of ambient light fluctuations, prevent ambient light from being included as noise, and suppress malfunction.

(Embodiment 2)
In the first embodiment, a configuration for mitigating the influence of ambient light fluctuation with one measurement has been described. In the second embodiment, a configuration for canceling the influence of ambient light fluctuation by two measurements will be described.

Since the overall configuration of the infrared measuring device according to the second embodiment is the same as the overall configuration of the infrared measuring device according to the first embodiment shown in FIG. 1, the same configuration is designated by the same reference numerals and detailed description will be given. Do not repeat.

FIG. 5 is a diagram for explaining the measurement timing of the ambient light and the reflected light in the infrared measuring device 100 according to the second embodiment. In FIG. 5, black circles indicate the measurement timing of infrared reflected light, and white circles indicate the measurement timing of ambient light. As shown in FIG. 5A, when the measurement of the infrared reflected light is the measurement timing A at which the irradiance of the ambient light peaks, the ambient light component is the ambient light before and after the measurement of the infrared reflected light. It becomes larger than the measured value of. Therefore, by obtaining the average value of the measured values of the measurement timing A and the measurement timing C at the position opposite to the measurement timing A, the influence of the ambient light fluctuation at the measurement timing A and the influence of the ambient light fluctuation at the measurement timing C can be obtained. Is offsetting.

In order to cancel the influence of the ambient light fluctuation by two measurements as described above, the ambient light is measured by the light receiving element 3a as shown in FIG. 5B to grasp the ambient light fluctuation, and then the predetermined timing is obtained. It is necessary to control the proximity measuring unit 50 to measure the infrared reflected light at a timing deviated by 1/2 of the fluctuation cycle from the predetermined timing. In FIG. 5B, a peak having a large measured value is defined as + P and a peak having a small measured value is defined as −P in the fluctuation period of ambient light. Then, for example, the MCU 44 has a period T1 from the peak of + P to the peak of −P, a period T2 from the peak of −P to the peak of + P, and a period of 1/2 of the fluctuation period (T1 + T2) of the ambient light (T1 + T2). 1/2 cycle) is calculated. The PS control logic 18 controls the proximity measurement unit 50 with a timing deviated by 1/2 of the fluctuation cycle from the first measurement timing as the second measurement timing.

Next, the measurement by the infrared measuring device 100 according to the second embodiment will be described with reference to the flowchart. FIG. 6 is a flowchart for explaining the measurement by the infrared measuring device 100 according to the second embodiment. First, the infrared measuring device 100 continuously measures the ambient light with the light receiving element 3a (step S20).

The infrared measuring device 100 detects the fluctuation cycle of the ambient light from the result obtained by continuous measurement in step S20, and determines whether or not the phase of the fluctuation cycle can be grasped (step S21). Specifically, the infrared measuring device 100 detects the fluctuation cycle (T1 + T2) of the ambient light as shown in FIG. 5B, and the fluctuation cycle is known at which timing of the fluctuation cycle of the ambient light. Grasp the phase of. When the phase of the fluctuation period cannot be grasped (NO in step S21), the infrared measuring device 100 returns the process to step S20 and continues the continuous measurement of ambient light. If the fluctuation period and phase of the ambient light cannot be grasped, the infrared measuring device 100 determines that the ambient light has no flicker component, and measures the infrared reflected light at the normal measurement timing (default timing). May be good.

When the phase of the fluctuation period can be grasped (YES in step S21), the infrared measuring device 100 calculates the measurement timing of the infrared reflected light based on the grasped phase (step S22). Specifically, as shown in FIG. 5B, the infrared measuring device 100 calculates a period deviation timing of 1/2 of the fluctuation cycle from the first measurement timing as the second measurement timing. The timing of the second measurement is not limited to the timing deviated by a period of 1/2 of the fluctuation cycle from the timing of the first measurement, and may be a timing deviated by a period that can offset the influence of ambient light fluctuation.

The infrared measuring device 100 measures the first infrared reflected light at the measurement timing (step S23). The infrared measuring device 100 measures the infrared reflected light at the timing of the first black circle shown in FIG. 5 (b). The first measurement timing may be the timing immediately after the calculation of the second measurement timing in step S22, or the timing after waiting for a predetermined period (for example, the period until the peak of the next ambient light fluctuation cycle). May be good.

The infrared measuring device 100 calculates the first infrared reflected light illuminance from the difference from the average value of the ambient light before and after the infrared reflected light measured in step S23 (step S24). The infrared measuring device 100 obtains an average value from the measured values of the ambient light of the white circles before and after the first black circle shown in FIG. 5 (b), and obtains the average value from the measured values of the infrared reflected light of the first black circle. Subtract the average value.

The infrared measuring device 100 measures the second infrared reflected light at a measurement timing deviated by a period of 1/2 of the fluctuation cycle from the first measurement timing (step S25). The infrared measuring device 100 measures the infrared reflected light at the timing of the second black circle shown in FIG. 5 (b).

The infrared measuring device 100 calculates the second infrared reflected light illuminance from the difference from the average value of the ambient light before and after the infrared reflected light measured in step S25 (step S26). The infrared measuring device 100 obtains an average value from the measured values of the ambient light of the white circles before and after the second black circle shown in FIG. 5 (b), and obtains the average value from the measured values of the infrared reflected light of the second black circle. Subtract the average value.

The infrared measuring device 100 calculates an average value of the first infrared reflected light illuminance and the second infrared reflected light illuminance (step S27). The infrared measuring device 100 outputs the calculated average value as the infrared reflected light illuminance. As a result, the infrared measuring device 100 can obtain the infrared reflected light illuminance substantially excluding the influence of ambient light fluctuation.

As described above, in the infrared measuring device 100 according to the second embodiment, the proximity measuring unit 50 has a first measured value at a predetermined timing and a timing deviated by 1/2 of the fluctuation cycle from the predetermined timing. , The second measured value and the third measured value are output twice, and the MCU 44 obtains each infrared reflected light illuminance from the measured values output twice, and calculates the average of the infrared reflected light illuminance obtained twice. To do.

The infrared measuring device 100 according to the second embodiment cancels out the influence of ambient light fluctuation by measuring twice with a shift of 1/2 of the fluctuation cycle to prevent ambient light from being included as noise and malfunction. Can be suppressed.

The infrared measuring device 100 according to the second embodiment may be combined with the configuration described in the first embodiment. Specifically, in the infrared measuring device 100 according to the second embodiment, the first infrared reflected light illuminance is set to a timing deviated from the peak of the fluctuation cycle by 1/4 cycle, and the second measurement timing is set to the first infrared. The timing is set to deviate by 1/2 of the fluctuation period from the reflected light illuminance.

(Embodiment 3)
In the first and second embodiments, a configuration is described in which the ambient light fluctuation is a sine wave or a waveform close to a sine wave to mitigate the influence of the ambient light fluctuation. However, when the light from the light source 41 is dimmed, the ambient light fluctuation is not a sine wave but a rectified waveform. In the third embodiment, a configuration for mitigating the influence of the ambient light fluctuation when the ambient light fluctuation does not become a sine wave will be described.

Since the overall configuration of the infrared measuring device according to the third embodiment is the same as the overall configuration of the infrared measuring device according to the first embodiment shown in FIG. 1, the same configuration is designated by the same reference numerals and detailed description will be given. Do not repeat.

FIG. 7 is a diagram for explaining the timing of two measurements by the infrared measuring device 100 according to the third embodiment. In FIG. 7, black circles indicate the measurement timing of infrared reflected light, and white circles indicate the measurement timing of ambient light. As shown in FIG. 7, the waveform of ambient light fluctuation is not a sine wave but a rectified waveform. Therefore, even if the timing at which the measurement of the infrared reflected light deviates by 1/2 of the fluctuation cycle from the first measurement timing D at which the irradiance of the ambient light peaks is set as the second measurement timing E, the measurement timing D and the measurement timing E is not in the opposite phase position. Therefore, even if the average value of the measured values of the measurement timing D and the measurement timing E is obtained, the influence of the ambient light fluctuation at the measurement timing D and the influence of the ambient light fluctuation at the measurement timing E cannot be offset. ..

In the infrared measuring device 100 according to the third embodiment, in order to cope with the case where the light from the light source 41 is dimmed, the ambient light is continuously measured and flicker information (for example, fluctuation period, fluctuation timing, etc.) The measurement timing is calculated by detecting). FIG. 8 is a diagram for explaining the measurement timing of the ambient light and the reflected light in the infrared measuring device according to the third embodiment.

As shown in FIG. 8A, the infrared measuring device 100 detects flicker information by continuously measuring only ambient light during a non-calling period or the like before performing proximity measurement during a smartphone call. .. The infrared measuring device 100 calculates the measurement timing based on the detected flicker information.

In FIG. 8B, as measurement timings, the wait time B (first waiting time) until the MCU 44 starts the measurement of the proximity measurement unit 50, and the wait time C from the wait time B to the next measurement ( Second waiting time) is calculated. That is, in a waveform that is not a sine wave as shown in FIG. 8B, the MCU 44 calculates the timing at which the peak (data A) of the ambient light waveform is removed as the Wait time B, and then adjusts to the repetition period of the waveform. The Wait time C is calculated. In the infrared measuring device 100, as shown in FIG. 1, the proximity measuring unit 50 has a function of measuring the ambient light, so that the period of the ambient light (flicker) and the period of the proximity measurement can be synchronized. .. As a result, the infrared measuring device 100 can use not only the periodic information of the ambient light but also the phase information, and can generate the measurement timing including the information of the Wait time B and the Wait time C.

Next, the measurement by the infrared measuring device 100 according to the third embodiment will be described with reference to the flowchart. FIG. 9 is a flowchart for explaining the measurement by the infrared measuring device 100 according to the third embodiment. First, the infrared measuring device 100 continuously measures the ambient light with the light receiving element 3a (step S30).

The infrared measuring device 100 detects the fluctuation cycle of the ambient light from the result obtained by continuous measurement in step S30, and determines whether or not the phase of the fluctuation cycle can be grasped (step S31). Specifically, as shown in FIG. 8A, the infrared measuring device 100 detects flicker information from the period of only ambient light measurement, and has a fluctuation cycle so that the timing of the ambient light waveform to be measured can be known. Grasp the phase of. If the phase of the fluctuation period cannot be grasped (NO in step S31), the infrared measuring device 100 returns the process to step S30 and continues the continuous measurement of ambient light. If the fluctuation period and phase of the ambient light cannot be grasped, the infrared measuring device 100 determines that the ambient light has no flicker component, and measures the infrared reflected light at the normal measurement timing (default timing). May be good.

When the phase of the fluctuation period can be grasped (YES in step S31), the infrared measuring device 100 calculates the measurement timing of the infrared reflected light based on the grasped phase (step S22). Specifically, the infrared measuring device 100 calculates Wait time B (first waiting time) and Wait time C (second waiting time) as shown in FIG. 8B.

The infrared measuring device 100 measures the first infrared reflected light after the wait time B from the peak of the waveform (data A) (step S33). The infrared measuring device 100 measures the infrared reflected light at the timing of the first black circle shown in FIG. 8 (b).

The infrared measuring device 100 calculates the first infrared reflected light illuminance from the difference from the average value of the ambient light before and after the infrared reflected light measured in step S33 (step S34). The infrared measuring device 100 obtains an average value from the measured values of the ambient light of the white circles before and after the first black circle shown in FIG. 8 (b), and obtains the average value from the measured values of the infrared reflected light of the first black circle. Subtract the average value.

The infrared measuring device 100 measures the second infrared reflected light after the Wait time C from the first measurement timing (step S35). The infrared measuring device 100 measures the infrared reflected light at the timing of the second black circle shown in FIG. 8 (b).

The infrared measuring device 100 calculates the second infrared reflected light illuminance from the difference from the average value of the ambient light before and after the infrared reflected light measured in step S35 (step S36). The infrared measuring device 100 obtains an average value from the measured values of the ambient light of the white circles before and after the second black circle shown in FIG. 8 (b), and obtains the average value from the measured values of the infrared reflected light of the second black circle. Subtract the average value.

After that, the infrared measuring device 100 measures the infrared reflected light every Wait time C (step S37). After that, the infrared measuring device 100 calculates the infrared reflected light illuminance from the second time onward from the difference from the average value of the ambient light before and after the infrared reflected light measured for each Wait time C until the proximity measurement is completed.

As described above, in the infrared measuring device 100 according to the third embodiment, the first waiting time (wait time B) until the PS control logic 18 starts the measurement of the proximity measuring unit 50 at a predetermined timing. , And the proximity measurement unit 50 is controlled to measure the infrared reflected light so that the second waiting time (wait time C) from the first waiting time to the next measurement is obtained.

When the infrared measuring device 100 according to the third embodiment calculates the first waiting time (wait time B) and the second waiting time (wait time C) so that the ambient light fluctuation does not become a sine wave. However, by measuring at a timing when the influence of ambient light fluctuation is small and mitigating the influence of ambient light fluctuation, it is possible to prevent ambient light from being included as noise and suppress malfunction.

(Embodiment 4)
In the third embodiment, it has been described that the infrared measuring device 100 detects flicker information by continuously measuring only ambient light during a non-calling period or the like before performing proximity measurement during a smartphone call. However, the light from the light source 41 is not always stable. In the fourth embodiment, a configuration for confirming whether or not the ambient light fluctuation is stable and mitigating the influence of the ambient light fluctuation will be described.

Since the overall configuration of the infrared measuring device according to the fourth embodiment is the same as the overall configuration of the infrared measuring device according to the first embodiment shown in FIG. 1, the same configuration is designated by the same reference numerals and detailed description will be given. Do not repeat.

For example, when a person holding a smartphone moves in a room, the ambient light incident on the infrared measuring device 100 may fluctuate due to factors other than flicker. Therefore, it is necessary for the infrared measuring device 100 to newly acquire the ambient light fluctuation by confirming whether the ambient light fluctuation is stable or the ambient light fluctuation is still acquired before a predetermined cycle.

In the infrared measuring device 100 according to the fourth embodiment, after confirming whether or not the light from the light source 41 is stable, the ambient light is continuously measured and flicker information (for example, information such as fluctuation cycle and fluctuation timing) is obtained. Included) is detected to calculate the measurement timing. FIG. 10 is a diagram for explaining the measurement timing of the ambient light and the reflected light in the infrared measuring device according to the fourth embodiment.

As shown in FIG. 10, the infrared measuring device 100 detects flicker information by continuously measuring only ambient light during a non-calling period or the like before performing proximity measurement during a smartphone call. However, accurate flicker information cannot be obtained unless the ambient light fluctuation is stable. Therefore, the infrared measuring device 100 continuously measures only the ambient light to determine whether or not the ambient light fluctuation is stable, and acquires flicker information when the ambient light fluctuation is stable. For example, as shown in FIG. 10, the infrared measuring device 100 determines that the peak level does not change significantly during the three cycles, determines that the period is stable, and continuously measures only the ambient light after that to obtain flicker information. get.

Next, the measurement by the infrared measuring device 100 according to the fourth embodiment will be described with reference to the flowchart. FIG. 11 is a flowchart for explaining the measurement by the infrared measuring device 100 according to the fourth embodiment. First, the infrared measuring device 100 continuously measures the ambient light with the light receiving element 3a (step S40).

The infrared measuring device 100 determines whether or not a predetermined cycle and a fluctuation cycle of ambient light are detected (step S41). For example, if the infrared reflected light is measured in the fluctuation cycle of the ambient light 100 cycles (predetermined cycle) before, the fluctuation cycle of the ambient light changes due to the movement of a person, and the influence of the ambient light fluctuation is sufficiently mitigated. I can't. Therefore, if the fluctuation cycle of the ambient light has not been detected for 100 cycles (predetermined cycle), the detection is performed again in order to update the fluctuation cycle.

When the predetermined cycle and the fluctuation cycle of the ambient light are not detected (YES in step S41), the infrared measuring device 100 determines whether or not the detected fluctuation cycle of the ambient light is stable (step S42). When the detected fluctuation cycle of the ambient light is not stable (NO in step S42), the infrared measuring device 100 returns the process to step S40 and continues the continuous measurement of the ambient light.

When the detected ambient light fluctuation cycle is stable (YES in step S42), the infrared measuring device 100 detects the ambient light fluctuation cycle from the results obtained by continuous measurement in step S40, and detects the fluctuation cycle. The phase of (step S43) is grasped. Specifically, when the infrared measuring device 100 determines that the period is stable as shown in FIG. 10, it detects flicker information from the period of only ambient light measurement, and at what timing of the ambient light waveform is measured. Grasp the phase of the fluctuation period so that you can see. If the fluctuation period and phase of the ambient light cannot be grasped, the infrared measuring device 100 determines that the ambient light has no flicker component, and measures the infrared reflected light at the normal measurement timing (default timing). May be good.

When the fluctuation cycle of the ambient light is detected at a predetermined cycle (NO in step S41), or when the phase of the fluctuation cycle is grasped in step S43, the infrared measuring device 100 determines the infrared reflected light based on the grasped phase. The measurement timing of (step S44) is calculated. Specifically, the infrared measuring device 100 calculates the Wait time B (first waiting time) and the Wait time C (second waiting time) as shown in FIG. 8B.

The infrared measuring device 100 measures the first infrared reflected light after the wait time B from the peak of the waveform (data A) (step S45). The infrared measuring device 100 measures the infrared reflected light at the timing of the first black circle shown in FIG. 8 (b).

The infrared measuring device 100 calculates the first infrared reflected light illuminance from the difference from the average value of the ambient light before and after the infrared reflected light measured in step S45 (step S46). The infrared measuring device 100 obtains an average value from the measured values of the ambient light of the white circles before and after the first black circle shown in FIG. 8 (b), and obtains the average value from the measured values of the infrared reflected light of the first black circle. Subtract the average value.

The infrared measuring device 100 measures the second infrared reflected light after the Wait time C from the first measurement timing (step S47). The infrared measuring device 100 measures the infrared reflected light at the timing of the second black circle shown in FIG. 8 (b).

The infrared measuring device 100 calculates the second infrared reflected light illuminance from the difference from the average value of the ambient light before and after the infrared reflected light measured in step S35 (step S48). The infrared measuring device 100 obtains an average value from the measured values of the ambient light of the white circles before and after the second black circle shown in FIG. 8 (b), and obtains the average value from the measured values of the infrared reflected light of the second black circle. Subtract the average value.

After that, the infrared measuring device 100 measures the infrared reflected light every Wait time C (step S49). After that, the infrared measuring device 100 calculates the infrared reflected light illuminance from the second time onward from the difference from the average value of the ambient light before and after the infrared reflected light measured for each Wait time C until the proximity measurement is completed.

As described above, in the infrared measuring device 100 according to the third embodiment, the PS control logic 18 measures the ambient light with the proximity measuring unit 50 at predetermined cycles to update the fluctuation cycle.

The infrared measuring device 100 according to the fourth embodiment confirms whether or not the ambient light fluctuation is stable and alleviates the influence of the ambient light fluctuation. Therefore, it is possible to prevent the ambient light from being included as noise and malfunction. Can be suppressed.

(Modification example)
In the above-described embodiment, since the wavelength of the light to be detected differs between the flicker measurement and the proximity measurement, the infrared measuring device 100 provides a light receiving element 3a for flicker measurement and a light receiving element 3b for proximity measurement. The detection wavelength of the flicker measurement may be changed to infrared only, and the flicker measurement may be performed by the light receiving element for proximity measurement.

FIG. 12 is a block diagram showing the configuration of the infrared measuring device 100a according to the modified example. FIG. 13 is a diagram showing a configuration of a light receiving element of the infrared measuring device 100a according to a modified example. Of the overall configuration of the infrared measuring device 100 according to the modified example, the same configuration as the overall configuration of the infrared measuring device according to the first embodiment shown in FIG. 1 is designated by the same reference numeral and detailed description will not be repeated. ..

In the infrared measuring device 100a, as shown in FIG. 13, instead of providing the light receiving element 3a for flicker measurement and the light receiving element 3b for proximity measurement, only the light receiving element 3 is provided. The light receiving element 3 is composed of a photodiode having a visible light cut filter F on the light receiving surface, which cuts visible light and ultraviolet rays and transmits infrared rays in order to detect infrared rays with high sensitivity. Further, the light receiving element 3 may be composed of a photodiode having a sensitivity peak in the infrared region. Since only the light receiving element 3 is connected to the integrating circuit 4, the switches SW1 and SW2 are unnecessary as in the case of connecting the light receiving element 3a and the light receiving element 3b.

As shown in FIG. 12, the infrared measuring device 100a is based on the flicker analysis unit 50a that detects the period of ambient light in the proximity measuring unit 50 and grasps the phase of the fluctuation period, and the flicker information analyzed by the flicker analysis unit 50a. It may have a timing generation unit 50b for calculating the measurement timing of the infrared reflected light.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims, not the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 LED pulse generator, 2 infrared LED driver, 3,3a, 3b light receiving element, 4 integrating circuit, 5 AD converter, 6 log converter, 14 register circuit, 15 PS interface, 18 PS control logic, 41 light source, 50 Proximity measuring unit, 100, 100a infrared measuring device, 400 proximity object, 420 infrared light emitting diode.

Claims (9)

Infrared light emitting elements that irradiate nearby objects with infrared rays,
A measuring unit that measures infrared reflected light reflected by the nearby object while the infrared light emitting element is emitting light, or ambient light when the infrared light emitting element is not emitting light.
The infrared light emitting element and the control unit that controls the drive of the measurement unit at a predetermined timing based on the fluctuation cycle of the ambient light measured by the measurement unit.
It is provided with an arithmetic processing unit having a means for arithmetically processing the measurement data from the measuring unit and calculating the infrared reflected light illuminance.
The measuring unit has a first measured value in which the infrared rays are reflected by the nearby object at the predetermined timing, and the first measured value in a state where the infrared light emitting element is non-light emitting. The second measured value and the third measured value measured at the time before and after the measurement time of
The arithmetic processing unit is an infrared measuring device that calculates infrared reflected light illuminance by subtracting the average of the second measured value and the third measured value from the first measured value. The infrared measuring device according to claim 1, wherein the measuring circuit for measuring infrared light of the measuring unit shares the circuit with the measuring circuit for measuring the fluctuation cycle. The infrared measuring device according to claim 1 or 2, wherein the control unit controls the measuring unit to measure infrared reflected light by setting the predetermined timing as a timing when the peak of the fluctuation cycle is removed. .. 3. The control unit controls the measurement unit to measure infrared reflected light by setting the timing when the peak of the fluctuation cycle is removed as a timing which is 1/4 cycle off the peak of the fluctuation cycle. Infrared measuring device according to. The measuring unit obtains the first measured value, the second measured value, and the third measured value at the predetermined timing and the timing deviated by 1/2 of the fluctuation cycle from the predetermined timing. Output twice,
The infrared measuring device according to claim 1 or 2, wherein the arithmetic processing unit obtains each infrared reflected light illuminance from the measured values output twice and calculates the average of the infrared reflected light illuminance obtained twice. .. The control unit has a first waiting time until the measurement of the measuring unit is started and a second waiting time from the first waiting time to the next measurement at the predetermined timing. The infrared measuring device according to claim 1 or 2, wherein the measuring unit controls to measure infrared reflected light. The infrared measuring device according to any one of claims 1 to 6, wherein the control unit measures ambient light by the measuring unit and updates the fluctuation cycle at predetermined cycles. The infrared measuring device according to any one of claims 1 to 7, wherein the light receiving element that receives infrared light of the measuring unit shares the element with the light receiving element for measuring the fluctuation cycle. .. An infrared light emitting element that irradiates a nearby object with infrared rays, infrared reflected light reflected by the nearby object while the infrared light emitting element is emitting light, or surroundings in a non-light emitting state of the infrared light emitting element. From the measuring unit that measures the light, the infrared light emitting element at a predetermined timing based on the fluctuation cycle of the ambient light measured by the measuring unit, the control unit that controls the drive of the measuring unit, and the measuring unit. This is a measurement method for measuring infrared reflected light with an infrared measuring device including an arithmetic processing unit having a means for calculating infrared reflected light illuminance by arithmetically processing the measurement data of.
The step of measuring the ambient light in the non-light emitting state of the infrared light emitting element in the measuring unit,
A step of calculating the predetermined timing based on the fluctuation cycle measured by the measuring unit, and
The first measured value obtained by measuring the infrared reflected light reflected by the near object at the predetermined timing by the measuring unit, and the first measured value in a state where the infrared light emitting element does not emit light. The step of outputting the second measured value and the third measured value measured at the time before and after the measurement time of
A measuring method including a step of subtracting an average of the second measured value and the third measured value from the first measured value to calculate the infrared reflected light illuminance in the arithmetic processing unit.

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