JP2021131258A - Light detection system and discharge probability calculating method - Google Patents

Abstract

To calculate regular and irregular discharges' probabilities of an optical sensor.SOLUTION: A light detection system includes: a discharge probability calculating portion 202 that calculates discharge probabilities for a first state in which an optical sensor 1 is shielded, a second state in which a pulse width of a drive pulse voltage applied to the optical sensor 1 is different from the first state, a third state in which the optical sensor 1 is shielded, a fourth state in which the optical sensor 1 can be lighted, a fifth state in which a pulse width is different from the fourth state, and a sixth state in which the optical sensor 1 can be lighted and a pulse width is the same as the third state; a discharge probability calculating portion 203 that calculates a discharge probability of irregular discharge on the basis of sensitivity parameters stored in a sensitivity parameter storing portion 19 and the calculated discharge probabilities; a received light quantity calculating portion 206 that calculates received light quantity on the basis of the sensitivity parameters and the calculated discharge probabilities; and a discharge probability calculating portion 208 that calculates a discharge probability of regular discharge on the basis of the sensitivity parameters, the calculated discharge probabilities and the received light quantity.SELECTED DRAWING: Figure 1

Description

The present invention relates to a photodetection system that detects light such as a flame.

A photocell type ultraviolet sensor may be used as an optical sensor that detects the presence or absence of a flame based on the ultraviolet rays emitted from the light of a flame in a combustion furnace or the like. It has been observed that a non-regular discharge phenomenon (suspicious discharge) occurs due to a noise component other than the discharge due to the photoelectric effect in the discharge of the phototube type ultraviolet sensor.

Patent Document 1 proposes a flame detection system capable of controlling the pulse width of a drive pulse applied to an optical sensor, obtaining the amount of received discharge from a calculation, and determining the life of the flame sensor from the amount of light. However, the actual discharge of the optical sensor includes a non-regular discharge due to noise, which is collectively called a failure, and even if there is no light due to the flame, the discharge may occur and an erroneous detection may occur. In order to eliminate such false detection of discharge, it is necessary to consider a method for measuring the discharge probability in consideration of the noise component.

Further, in the flame detection system disclosed in Patent Document 2, a method of obtaining a light receiving amount in consideration of the discharge probability of a noise component other than the normal discharge has been proposed, and it is possible to accurately detect the presence or absence of a flame. There is. However, in the flame detection system disclosed in Patent Document 2, it is necessary that the discharge probability of the noise component is known.

Further, in the failure detection device disclosed in Patent Document 3, it is proposed to detect a failure due to self-discharge of the optical sensor by providing a shutter mechanism for blocking electromagnetic waves incident on the optical sensor. However, in the failure detection device disclosed in Patent Document 3, there is no discriminating method for distinguishing between regular discharge and non-regular discharge due to a change in measurement sensitivity due to the life of the optical sensor, and there is a possibility that failure detection may be erroneous. was there.
The above problems occur not only in the flame detection system but also in the light detection system using the optical sensor.

JP-A-2018-84422 JP-A-2018-84423 Japanese Unexamined Patent Publication No. 05-012581

The present invention has been made to solve the above problems, and is generated independently of the discharge probability of a normal discharge excluding noise components other than the discharge due to the photoelectric effect of the optical sensor and the amount of light received by the optical sensor. An object of the present invention is to provide an optical detection system and a discharge probability calculation method capable of calculating the discharge probability of a non-normal discharge due to a noise component.

The optical detection system of the present invention includes an optical sensor configured to detect light emitted from a light source, and an applied voltage generator configured to periodically apply a drive pulse voltage to the electrodes of the optical sensor. And a current detection unit configured to detect the discharge current of the optical sensor, and a discharge determination unit configured to detect the discharge of the optical sensor based on the discharge current detected by the current detection unit. A first state in which the optical sensor is shielded from light, a second state in which the optical sensor is shielded from light and the pulse width of the drive pulse voltage is different from the first state, and the optical sensor is shielded from light. In addition, the pulse width of the drive pulse voltage is the same as either of the first and second states, or a third state different from the first and second states, and the optical sensor is capable of collecting light and said. The pulse width of the drive pulse voltage is the same as either the first or second state, or the fourth state is different from the first and second states, and the optical sensor can collect light and the drive pulse voltage. Regarding each of the fifth state in which the pulse width of the above is different from the fourth state and the sixth state in which the optical sensor can collect light and the pulse width of the drive pulse voltage is the same as the third state. A first configuration configured to calculate the discharge probability based on the number of times the drive pulse voltage is applied by the applied voltage generator and the number of discharges detected by the discharge determination unit during the application of the drive pulse voltage. As known sensitivity parameters of the discharge probability calculation unit and the optical sensor, the current is generated independently of the reference light receiving amount of the optical sensor, the reference pulse width of the drive pulse voltage, and the pulse width of the drive pulse voltage. A storage unit configured to store in advance the discharge probability of a first-class non-normal discharge due to a noise component other than the discharge due to the photoelectric effect of the optical sensor, which is generated depending on the amount of light received by the optical sensor. , The sensitivity parameter stored in the storage unit, the discharge probability calculated by the first discharge probability calculation unit in the first, second, and third states, and the first, second, and so on. The noise component that is generated depending on the pulse width of the drive pulse voltage and not depending on the amount of light received by the optical sensor, based on the pulse width of the drive pulse voltage in the third state. Of the third type of non-regular discharge due to the noise component, which is generated independently of the discharge probability of the second type of non-regular discharge due to the above, the pulse width of the drive pulse voltage, and the amount of light received by the optical sensor. Second discharge probability calculation configured to calculate the discharge probability The unit, the sensitivity parameter stored in the storage unit, and the first discharge probability calculation unit calculated in the first, second, third, fourth, fifth, and sixth states. The fourth, fifth, and sixth states are based on the discharge probability and the pulse width of the drive pulse voltage in the first, second, third, fourth, fifth, and sixth states. The light receiving amount calculation unit configured to calculate the light receiving amount of the optical sensor at the time of, the sensitivity parameter stored in the storage unit, and the first discharge probability calculation in the sixth state. The discharge probability calculated by the unit, the pulse width of the drive pulse voltage in the sixth state, the discharge probability calculated by the second discharge probability calculation unit, and the light reception amount calculation unit are calculated. Based on the received light amount, the discharge probability of a normal discharge when the pulse width of the drive pulse voltage is the reference pulse width and the received light amount of the optical sensor is the reference light receiving amount is calculated. It is characterized by including a discharge probability calculation unit of 3.

Further, in one configuration example of the optical detection system of the present invention, the second discharge probability calculation unit calculates the first discharge probability when _{the reference pulse width T 0 of the drive pulse voltage is in the first state.} The discharge probability ₁ P ^* _{calculated by the unit, the discharge probability 2} P ^* calculated by the first discharge probability calculation unit in the second state, and the first discharge in the third state. ^{The discharge probability P *} calculated by the probability calculation unit, _{the pulse width T 1} of the drive pulse voltage in the _{first state, and the pulse width T 2} (T _{1) of the} drive pulse voltage in the second state. ≠ T ₂ ), based on the pulse width T of the drive pulse voltage in the third state, the discharge probability P _{aB of} the second type of non-normal discharge, and the third type of non-normal discharge. It is characterized in that the discharge probability P _{bB is calculated.}
Further, in one configuration example of the light detection system of the present invention, the light receiving amount calculation unit has a reference light receiving amount Q _{0 of the optical sensor, a discharge probability P bA of} the first type of non-normal discharge, and the first first type of discharge. _{The discharge probability 1} P ^* calculated by the first discharge probability calculation unit in _{the state, the discharge probability 2} P ^* calculated by the first discharge probability calculation unit in the second state, the first The discharge probability P ^* _{calculated by the first discharge probability calculation unit in the third state, the discharge probability 3} P calculated by the first discharge probability calculation unit in the fourth state, the first _{The discharge probability 4} P calculated by the first discharge probability calculation unit in the state of 5, the discharge probability P calculated by the first discharge probability calculation unit in the sixth state, the first _{The pulse width T 1} of the drive pulse voltage in _{the state of, the pulse width T 2} (T ₁ ≠ T ₂ ) of the drive pulse voltage in the second state, and the drive in the fourth state. The pulse width T _{3 of the pulse voltage, the pulse width T 4} (T ₃ ≠ T ₄ ) of the drive pulse voltage in the fifth state, and the pulse of the drive pulse voltage in the third and sixth states. It is characterized in that the light receiving amount Q of the optical sensor in the fourth, fifth, and sixth states is calculated based on the width T.
Further, in one configuration example of the optical detection system of the present invention, the third discharge probability calculation unit has a reference light receiving amount Q ₀ of the optical sensor, a reference pulse width T ₀ of the drive pulse voltage, and the first type. The discharge probability P _bA of the non-regular discharge, the discharge probability P _{aB of} the second type of non-regular discharge, the discharge probability P _{bB of} the third type of non-normal discharge, the third in the sixth state. Discharge probability P calculated by the discharge probability calculation unit of 1, the amount of light received by the optical sensor Q in the fourth, fifth, and sixth states, and the pulse of the drive pulse voltage in the sixth state. It is characterized in that _{the discharge probability P aA} of the normal discharge is calculated based on the width T.

Further, the optical detection system of the present invention includes an optical sensor configured to detect light emitted from a light source and an applied voltage configured to periodically apply a drive pulse voltage to the electrodes of the optical sensor. A generation unit, a current detection unit configured to detect the discharge current of the optical sensor, and a discharge configured to detect the discharge of the optical sensor based on the discharge current detected by the current detection unit. The determination unit, the first state in which the optical sensor is shielded from light, the second state in which the optical sensor is shielded from light and the pulse width of the drive pulse voltage is different from the first state, and the optical sensor It is possible to collect light, and the pulse width of the drive pulse voltage is the same as either of the first or second state, or a third state different from the first or second state, and the light sensor can collect light. In addition, for each of the fourth states in which the pulse width of the drive pulse voltage is different from the third state, the number of times the drive pulse voltage is applied by the applied voltage generator and the discharge during the application of the drive pulse voltage. A first discharge probability calculation unit configured to calculate the discharge probability based on the number of discharges detected by the determination unit, and a reference light receiving amount of the optical sensor as known sensitivity parameters of the optical sensor. , The reference pulse width of the drive pulse voltage and the noise other than the discharge due to the photoelectric effect of the optical sensor, which is generated independently of the pulse width of the drive pulse voltage and depending on the amount of light received by the optical sensor. A storage unit configured to store in advance the discharge probability of a first-class non-normal discharge due to a component, a sensitivity parameter stored in the storage unit, and the first and second states. Based on the discharge probability calculated by the first discharge probability calculation unit and the pulse width of the drive pulse voltage in the first and second states, it depends on the pulse width of the drive pulse voltage. The discharge probability of the second type of non-regular discharge due to the noise component, which is generated and is generated independently of the received light amount of the optical sensor, the pulse width of the drive pulse voltage, and the received light amount of the optical sensor. A second discharge probability calculation unit configured to calculate the discharge probability of a third-class non-normal discharge due to the noise component that occurs independently, and a sensitivity parameter stored in the storage unit. And the discharge probability calculated by the first discharge probability calculation unit in the first, second, third, and fourth states, and the first, second, third, and fourth states. Based on the pulse width of the drive pulse voltage at the time, the third and fourth The light receiving amount calculation unit configured to calculate the light receiving amount of the optical sensor in the state of, the sensitivity parameter stored in the storage unit, and the third and fourth states. The discharge probability calculated by the discharge probability calculation unit of 1, the pulse width of the drive pulse voltage in the third and fourth states, and the discharge probability calculated by the second discharge probability calculation unit. Based on the light receiving amount calculated by the light receiving amount calculation unit, the discharge probability of a normal discharge when the pulse width of the driving pulse voltage is the reference pulse width and the light receiving amount of the optical sensor is the reference light receiving amount is calculated. It is characterized by including a third discharge probability calculation unit configured to calculate.

Further, in one configuration example of the optical detection system of the present invention, the second discharge probability calculation unit calculates the first discharge probability when _{the reference pulse width T 0 of the drive pulse voltage is in the first state.} The discharge probability ₁ P ^* _{calculated by the unit, the discharge probability 2} P ^* calculated by the first discharge probability calculation unit in the second state, and the drive pulse voltage in the first state. Based on the pulse width T _{1 , the pulse width T 2} (T ₁ ≠ T ₂ ) of the drive pulse voltage in the second state, _{the discharge probability P aB of} the second type of non-normal discharge, the first It is characterized in that _{the discharge probabilities P bB} of three types of non-regular discharges are calculated.
Further, in one configuration example of the light detection system of the present invention, the light receiving amount calculation unit has a reference light receiving amount Q _{0 of the optical sensor, a discharge probability P bA of} the first type of non-normal discharge, and the first first type of discharge. _{The discharge probability 1} P ^* calculated by the first discharge probability calculation unit in _{the state, the discharge probability 2} P ^* calculated by the first discharge probability calculation unit in the second state, the first _{The discharge probability 3} P calculated by the first discharge probability calculation unit in _{the state of 3, the discharge probability 4} P calculated by the first discharge probability calculation unit in the fourth state, the first _{The pulse width T 1} of the drive pulse voltage in the state of 1, the pulse width T ₂ (T ₁ ≠ T ₂ ) of the drive pulse voltage in the second state, and the said in the third state. Based on the pulse width T _{3 of} the drive pulse voltage and the pulse width T ₄ (T ₃ ≠ T ₄ ) of the drive pulse voltage in the fourth state, the light in the third and fourth states. It is characterized in that the light receiving amount Q of the sensor is calculated.
Further, in one configuration example of the optical detection system of the present invention, the third discharge probability calculation unit has a reference light receiving amount Q ₀ of the optical sensor, a reference pulse width T ₀ of the drive pulse voltage, and the first type. The discharge probability P _bA of the non-regular discharge, the discharge probability P _{aB of} the second type of non-normal discharge, the discharge probability P _{bB of} the third type of non-normal discharge, and the third state in the third state. Discharge probability ₃ P calculated by the discharge probability calculation unit of 1, discharge probability ₄ P calculated by the first discharge probability calculation unit in the fourth state, and in the third and fourth states. The received amount Q of the optical sensor, the pulse width T _{3 of the drive pulse voltage in the third state, and the pulse width T 4} of the drive pulse voltage in the fourth state (T ₃ ≠ T _4). ), The discharge probability P _aA of the normal discharge is calculated.
Further, one configuration example of the photodetector system of the present invention includes a light-shielding means provided between the light source and the light sensor, and a state in which the light sensor is shielded by opening and closing the light-shielding means. It is characterized by further including a shutter control unit configured to switch between a light sensor and a state in which light can be collected.

Further, in the discharge probability calculation method of the optical detection system of the present invention, a drive pulse voltage is periodically applied to the electrodes of the optical sensor when the optical sensor that detects the light emitted from the light source is in the first state of being shielded from light. The discharge of the optical sensor is based on the first step of applying, the second step of detecting the discharge current of the optical sensor in the first state, and the discharge current in the first state. The first step is based on the third step of detecting the above, the number of times the drive pulse voltage is applied by the first step, and the number of discharges detected in the third step while the drive pulse voltage is being applied. In the fourth step of calculating the discharge probability in the state of, and in the second state where the optical sensor is shielded from light and the pulse width of the drive pulse voltage is different from the first state, the optical sensor A fifth step of periodically applying a drive pulse voltage to the electrodes, a sixth step of detecting the discharge current of the optical sensor in the second state, and the discharge in the second state. The seventh step of detecting the discharge of the optical sensor based on the current, the number of times the drive pulse voltage is applied by the fifth step, and the discharge detected in the seventh step while the drive pulse voltage is applied. The eighth step of calculating the discharge probability in the second state based on the number of times of the above, and the first and second states in which the optical sensor is shielded from light and the pulse width of the drive pulse voltage is the first and second states. In the ninth step of periodically applying a drive pulse current to the electrode of the optical sensor in the third state different from the first and second states, which is the same as either of them, and in the third state. According to the tenth step of detecting the discharge current of the optical sensor, the eleventh step of detecting the discharge of the optical sensor based on the discharge current in the third state, and the ninth step. A twelfth step of calculating the discharge probability in the third state based on the number of times the drive pulse voltage is applied and the number of times of discharge detected in the eleventh step while the drive pulse voltage is applied. As known sensitivity parameters of the optical sensor, the current is generated independently of the reference light receiving amount of the optical sensor, the reference pulse width of the drive pulse voltage, and the pulse width of the drive pulse voltage, and is received by the optical sensor. Referencing a storage unit that previously stores the discharge probability of the first type of non-normal discharge due to noise components other than the discharge due to the photoelectric effect of the optical sensor, which is generated depending on the amount, and is stored in this storage unit. Sensitivity parameters and the above The pulse width of the drive pulse voltage is based on the discharge probability calculated in the fourth, eighth, and twelfth steps and the pulse width of the drive pulse voltage in the first, second, and third states. The discharge probability of the second type of non-regular discharge due to the noise component, the pulse width of the drive pulse voltage, and the optical sensor, which are generated depending on the amount of light received by the optical sensor. The thirteenth step of calculating the discharge probability of the third type of non-regular discharge due to the noise component, which is generated independently of the amount of received light, and the optical sensor can collect light and the drive pulse voltage When the pulse width is the same as either the first or second state, or in the fourth state different from the first and second states, the drive pulse voltage is periodically applied to the electrodes of the optical sensor. The discharge of the optical sensor is detected based on the 14 steps, the fifteenth step of detecting the discharge current of the optical sensor in the fourth state, and the discharge current in the fourth state. The fourth state is based on the 16th step, the number of times the drive pulse voltage is applied by the 14th step, and the number of discharges detected in the 16th step during the application of the drive pulse voltage. The 17th step of calculating the discharge probability at the time, and the electrode of the optical sensor when the optical sensor is capable of collecting light and the pulse width of the drive pulse voltage is different from the fourth state in the fifth state. To the 18th step of periodically applying the drive pulse voltage, the 19th step of detecting the discharge current of the optical sensor in the fifth state, and the discharge current in the fifth state. Based on the 20th step of detecting the discharge of the optical sensor, the number of times the drive pulse voltage is applied by the 18th step, and the number of times of the discharge detected in the 20th step during the application of the drive pulse voltage. The 21st step of calculating the discharge probability in the 5th state based on the above, and the 6th step in which the optical sensor can collect light and the pulse width of the drive pulse voltage is the same as that in the third state. The 22nd step of periodically applying the drive pulse voltage to the electrodes of the optical sensor in the state, the 23rd step of detecting the discharge current of the optical sensor in the 6th state, and the said second step. The 24th step of detecting the discharge of the optical sensor based on the discharge current in the state of 6, the number of times the drive pulse voltage is applied by the 22nd step, and the drive pulse voltage being applied during the application of the drive pulse voltage. Discharge detected in the 24th step The 25th step of calculating the discharge probability in the sixth state based on the number of times of the above, the sensitivity parameter stored in the storage unit, and the fourth, eighth, twelfth, and seventeenth steps. Based on the discharge probability calculated in the 21st and 25th steps and the pulse width of the drive pulse voltage in the first, second, third, fourth, fifth, and sixth states, the said The 26th step of calculating the amount of light received by the optical sensor in the 4th, 5th, and 6th states, the sensitivity parameter stored in the storage unit, and the discharge probability calculated in the 25th step. The drive pulse voltage is based on the pulse width of the drive pulse voltage in the sixth state, the discharge probability calculated in the thirteenth step, and the received light amount calculated in the twenty-sixth step. It is characterized by including a 27th step of calculating the discharge probability of a normal discharge when the pulse width of the above is the reference pulse width and the light receiving amount of the optical sensor is the reference light receiving amount.

Further, in the discharge probability calculation method of the optical detection system of the present invention, a drive pulse voltage is periodically applied to the electrodes of the optical sensor when the optical sensor that detects the light emitted from the light source is in the first state of being shielded from light. The discharge of the optical sensor is based on the first step of applying, the second step of detecting the discharge current of the optical sensor in the first state, and the discharge current in the first state. The first step is based on the third step of detecting the above, the number of times the drive pulse voltage is applied by the first step, and the number of discharges detected in the third step while the drive pulse voltage is being applied. In the fourth step of calculating the discharge probability in the state of, and in the second state where the optical sensor is shielded from light and the pulse width of the drive pulse voltage is different from the first state, the optical sensor A fifth step of periodically applying a drive pulse voltage to the electrodes, a sixth step of detecting the discharge current of the optical sensor in the second state, and the discharge in the second state. The seventh step of detecting the discharge of the optical sensor based on the current, the number of times the drive pulse voltage is applied by the fifth step, and the discharge detected in the seventh step while the drive pulse voltage is applied. The eighth step of calculating the discharge probability in the second state based on the number of times of the above, and as known sensitivity parameters of the optical sensor, the reference light receiving amount of the optical sensor and the reference of the drive pulse voltage. The first kind of non-type 1 due to noise components other than discharge due to the photoelectric effect of the optical sensor, which is generated independently of the pulse width and the pulse width of the drive pulse voltage and depending on the amount of light received by the optical sensor. With reference to a storage unit that stores the discharge probability of a normal discharge in advance, the sensitivity parameters stored in this storage unit, the discharge probability calculated in the fourth and eighth steps, and the first and second steps. Based on the pulse width of the drive pulse voltage in the state of Discharge probability of two types of non-regular discharge and discharge probability of third type of non-regular discharge due to the noise component that occurs independently of the pulse width of the drive pulse voltage and the amount of light received by the optical sensor. The ninth step of calculating the above, and whether the optical sensor is capable of collecting light and the pulse width of the drive pulse voltage is the same as either of the first and second states, and the first and second states. On the electrode of the optical sensor in a different third state To the tenth step of periodically applying the drive pulse voltage, the eleventh step of detecting the discharge current of the optical sensor in the third state, and the discharge current in the third state. Based on the twelfth step of detecting the discharge of the optical sensor, the number of times the drive pulse voltage is applied by the tenth step, and the number of discharges detected in the twelfth step during the application of the drive pulse voltage. The thirteenth step of calculating the discharge probability in the third state based on the above, and the fourth step in which the optical sensor can collect light and the pulse width of the drive pulse voltage is different from that of the third state. A fourteenth step of periodically applying a drive pulse voltage to the electrodes of the optical sensor in the state, a fifteenth step of detecting the discharge current of the optical sensor in the fourth state, and the first step. The 16th step of detecting the discharge of the optical sensor based on the discharge current in the state of 4, the number of times the drive pulse voltage is applied by the 14th step, and the drive pulse voltage being applied during the application of the drive pulse voltage. The 17th step of calculating the discharge probability in the 4th state based on the number of discharges detected in the 16th step, the sensitivity parameter stored in the storage unit, and the 4th and 4th steps. Based on the discharge probability calculated in the eighth, thirteenth, and seventeenth steps and the pulse width of the drive pulse voltage in the first, second, third, and fourth states, the third and third The 18th step of calculating the light receiving amount of the optical sensor in the state of 4, the sensitivity parameter stored in the storage unit, the discharge probability calculated in the 13th and 17th steps, and the said thirteenth step. The drive pulse voltage of the drive pulse voltage is based on the pulse width of the drive pulse voltage in the third and fourth states, the discharge probability calculated in the ninth step, and the received light amount calculated in the eighteenth step. It is characterized by including a nineteenth step of calculating the discharge probability of a normal discharge when the pulse width is the reference pulse width and the light receiving amount of the optical sensor is the reference light receiving amount.

According to the present invention, an applied voltage generation unit, a current detection unit, a discharge determination unit, a first discharge probability calculation unit, a storage unit, a second discharge probability calculation unit, a light receiving amount calculation unit, and a third discharge probability calculation unit. by providing the bets, occurs depending on the pulse width of the drive pulse voltage and generated without depending on the amount of light received by the sensor, the discharge probability in the discharge of the second type of non-regular by noise Ingredient, The discharge probability of the third type of non-normal discharge due to the noise component, which is generated independently of the pulse width of the drive pulse voltage and the received amount of the optical sensor, the received amount of the optical sensor, and the regular excluding the noise component. It is possible to calculate the discharge probability of the discharge of. As a result, in the present invention, it is possible to realize the life determination of the optical sensor based on the received light amount, the discharge probability of the normal discharge, and the discharge probability of the non-normal discharge.

FIG. 1 is a block diagram showing a configuration of a photodetection system according to an embodiment of the present invention. FIG. 2 is a waveform diagram showing a drive pulse applied to the optical sensor and a detection voltage detected by the current detection circuit in the embodiment of the present invention. FIG. 3 is a flowchart illustrating the operation of the photodetection system according to the embodiment of the present invention. FIG. 4 is a flowchart illustrating the operation of the photodetection system according to the embodiment of the present invention. FIG. 5 is a flowchart illustrating another operation of the photodetection system according to the embodiment of the present invention. FIG. 6 is a flowchart illustrating another operation of the photodetection system according to the embodiment of the present invention. FIG. 7 is a block diagram showing a configuration example of a computer that realizes the photodetection system according to the embodiment of the present invention.

[Example]
Hereinafter, a method for measuring a normal discharge excluding a noise component and a method for measuring the amount of received light will be described. An optical sensor that utilizes the photoelectric effect is a photocell that energizes when a photon hits an electrode. Energization proceeds under the following conditions.

[Operation of optical sensor]
When a photon hits one of the electrodes while a voltage is applied between the pair of electrodes of the optical sensor, photoelectrons are likely to jump out and energize while causing electron avalanche (a discharge current flows between the electrodes).
While the voltage is applied between the electrodes, the optical sensor continues to be energized. Alternatively, as soon as the energization of the optical sensor is confirmed, the energization is stopped by lowering the voltage. In this way, the optical sensor ends energization when the voltage between the electrodes drops.

_{Let P 1} be the probability that the optical sensor will be discharged when one photon hits the electrode of the optical sensor. _{Also, let P 2} be the probability that the optical sensor will be discharged when two photons hit the electrodes of the optical sensor. Since P ₂ is the opposite of the probability that neither the first photon nor the second photon will be discharged, _{the relationship between P 2} and P ₁ is expressed by Eq. (1).

_{Generally, let P n be} the probability that the photosensor will be discharged when _{n photons hit the electrodes of the photosensor, and P m} be the probability that the photosensor will be discharged when m photons hit the electrodes of the photosensor. (N and m are natural numbers), and equations (2) and (3) hold as in equation (1).

From equations (2) and (3), equation (4) can be derived as the relationship between _{P n} and P _m.

If the number of photons flying to the electrodes of the optical sensor per unit time is E, and the time for applying a voltage equal to or higher than the discharge start voltage of the optical sensor between the electrodes (hereinafter referred to as pulse width) is T, voltage application 1 The number of photons that collide with the electrode per turn is represented by ET. Therefore, the relationship between the number of photons E, the pulse width T, and the discharge probability P when the same optical sensor is operated under a certain condition A and another condition B is as shown in the equation (5). Here, if the reference number of photons _{is set to E 0} and Q = E / E ₀ , then the equation (6) is obtained. Here, Q is referred to as a light receiving amount.

[Configuration and operation of optical detection system]
FIG. 1 is a block diagram showing a configuration of a photodetection system according to an embodiment of the present invention. The photodetection system drives an optical sensor and calculates the amount of light received from the driving result of the optical sensor. This light detection system includes an optical sensor 1 that detects light (ultraviolet rays) generated from a light source 100 such as a flame, an LED, or a lamp, an external power supply 2, a computing device 3 to which the optical sensor 1 and the external power supply 2 are connected. It includes a shutter 21 provided between the light source 100 and the light sensor 1, a shutter drive unit 22 that drives the shutter 21, and a shutter control unit 23 that controls the shutter 21 through the shutter drive unit 22. The shutter 21 and the shutter driving unit 22 form a light-shielding means.

The optical sensor 1 is supported by a cylindrical enclosure with both ends closed, two electrode pins penetrating both ends of the enclosure, and electrode pins inside the enclosure in parallel with each other. It is composed of a phototube provided with two electrodes. In such an optical sensor 1, when a predetermined voltage is applied between the electrodes via the electrode support pins and ultraviolet rays are applied to one of the electrodes arranged to face the light source 100, the electrode has a photoelectric effect. Electrons are emitted and a discharge current flows between the electrodes.

The external power supply 2 comprises, for example, an AC commercial power supply having a voltage value of 100 [V] or 200 [V].

The arithmetic unit 3 includes a power supply circuit 11 connected to an external power supply 2, an applied voltage generation circuit 12 and a trigger circuit 13 connected to the power supply circuit 11, a terminal 1b on the downstream side of the optical sensor 1, and a grounding line GND. The voltage (reference voltage) Va generated at the connection point Pa between the resistors R1 and R2 of the voltage dividing resistor 14 and the voltage dividing resistor 14 composed of the resistors R1 and R2 connected in series between the two flows through the optical sensor 1. It includes a current detection circuit 15 that detects as a current I, and a processing circuit 16 in which an applied voltage generation circuit 12, a trigger circuit 13, and a current detection circuit 15 are connected.

The power supply circuit 11 supplies AC power input from the external power supply 2 to the applied voltage generation circuit 12 and the trigger circuit 13. Further, the electric power for driving the arithmetic unit 3 is acquired from the power supply circuit 11. However, it can also be configured to acquire driving power from another power source regardless of AC / DC.

The applied voltage generation circuit 12 (applied voltage generation unit) boosts the AC voltage applied by the power supply circuit 11 to a predetermined value and applies it to the optical sensor 1. In this embodiment, a pulsed voltage of 200 [V] synchronized with the rectangular pulse PS from the processing circuit 16 ( _{voltage equal to or higher than the discharge start voltage VST} of the optical sensor 1) is generated as the drive pulse voltage PM, and this generation is performed. The driven pulse voltage PM is applied to the optical sensor 1. FIG. 2 shows the drive pulse voltage PM applied to the optical sensor 1. The drive pulse voltage PM is synchronized with the rectangular pulse PS from the processing circuit 16, and its pulse width T is equal to the pulse width of the rectangular pulse PS. The rectangular pulse PS from the processing circuit 16 will be described later.

The trigger circuit 13 detects a predetermined value point of the AC voltage applied by the power supply circuit 11, and inputs the detection result to the processing circuit 16. In this embodiment, the trigger circuit 13 detects the minimum value point at which the voltage value becomes the minimum as a predetermined value point (at the time of triggering). By detecting a predetermined value point for the AC voltage in this way, it is possible to detect one cycle of the AC voltage.

The voltage dividing resistor 14 generates a reference voltage Va as a voltage dividing voltage between the resistors R1 and R2, and inputs the reference voltage Va to the current detection circuit 15. Here, the voltage value of the drive pulse PM applied to the terminal 1a on the upstream side of the optical sensor 1 is as high as 200 [V] as described above, so that a current is generated between the electrodes of the optical sensor 1. If the voltage generated in the terminal 1b on the downstream side when the current flows is input to the current detection circuit 15 as it is, a large load will be applied to the current detection circuit 15. Therefore, in this embodiment, the voltage dividing resistor 14 generates a reference voltage Va having a low voltage value, and this is input to the current detection circuit 15.

The current detection circuit 15 (current detection unit) detects the reference voltage Va input from the voltage dividing resistor 14 as the discharge current I of the optical sensor 1, and inputs the detected reference voltage Va as the detection voltage Vpv to the processing circuit 16. do.
The processing circuit 16 includes a square pulse generation unit 17, an A / D conversion unit 18, a sensitivity parameter storage unit 19, and a central processing unit 20.

The rectangular pulse generation unit 17 generates a rectangular pulse PS having a pulse width T every time the trigger circuit 13 detects the trigger time point, that is, every cycle of the AC voltage applied from the power supply circuit 11 to the trigger circuit 13. The square pulse PS generated by the square pulse generation unit 17 is sent to the applied voltage generation circuit 12. The rectangular pulse generation unit 17 and the applied voltage generation circuit 12 can adjust the pulse width of the drive pulse voltage PM. That is, when the rectangular pulse generation unit 17 sets the pulse width of the rectangular pulse PS to a desired value, the drive pulse voltage PM having a pulse width equal to that of the rectangular pulse PS is output from the applied voltage generation circuit 12.
The A / D conversion unit 18 A / D converts the detection voltage Vpv from the current detection circuit 15 and sends it to the central processing unit 20.

The central processing unit 20 is realized by hardware composed of a processor and a storage device and a program that realizes various functions in cooperation with these hardware, and includes a discharge determination unit 201, a discharge probability calculation unit 202, 203, and the like. It functions as 208, a pulse application number integration unit 204, an application number determination unit 205, a light reception amount calculation unit 206, and a light reception amount determination unit 207.

In the central processing unit 20, the discharge determination unit 201 detects the discharge of the optical sensor 1 based on the discharge current of the optical sensor 1 detected by the current detection circuit 15. Specifically, the discharge determination unit 201 determines the detection voltage Vpv input from the A / D conversion unit 18 each time the drive pulse voltage PM is applied to the optical sensor 1 (every time a rectangular pulse PS is generated). It is compared with a predetermined threshold voltage Vth (see FIG. 2), and when the detected voltage Vpv exceeds the threshold voltage Vth, it is determined that the optical sensor 1 has been discharged, and the number of discharges n is increased by 1.

The discharge probability calculation unit 202 performs the discharge determination unit 201 when the number of times N of the drive pulse voltage PM applied to the optical sensor 1 exceeds a predetermined number (when the number of pulses of the rectangular pulse PS exceeds a predetermined number). The discharge probability P of the optical sensor 1 is calculated from the number of discharges n detected by the above and the number of times N of application of the drive pulse voltage PM.

This discharge probability P is output as a frame signal. Certain operating conditions, the received light amount _{Q 0 (Q 0 ≠ 0)} , the discharge probability P ₀ of the pulse width T ₀ is known. For example, in the shipping inspection of a photodetection system, there is a method of measuring the discharge probability P at a predetermined light receiving amount and pulse width. At this time, the relationship between the received light amount Q, the pulse width T, and the discharge probability P is given by the equation (7). However, P = 0 is Q = 0. In the present invention, when P = 0 and P = 1, it is excluded from the calculation process of the received light amount Q.

Now, Q ₀ , T ₀ , and P ₀ are known, and T is known because the pulse width is controlled by the photodetection system. If the drive pulse voltage PM is applied to the optical sensor 1 a plurality of times, the number of discharges n is measured, and the discharge probability P is calculated, the light receiving amount Q, which is an unknown number, can be calculated from the equation (7). This received light amount Q may be output as a frame signal.

[Operation of photodetection system considering noise]
From the equation (7), it is assumed that the discharge probability P _{aA at} a certain operating condition, the light receiving amount Q ₀ , and the pulse width T ₀ is known, and the relationship between the received light amount Q, the pulse width T, and the discharge probability P is expressed by the equation (8). Given.

The following two can be considered as the relationship between the discharge of the optical sensor 1 and the time.
(A) Discharge that appears with a uniform probability while the drive pulse voltage PM is applied (Equation (8)).
(B) Drive pulse voltage A discharge that appears when the PM rises or falls.

Next, the relationship between the discharge of the optical sensor 1 and the amount of light received can be considered as follows.
(A) A discharge that appears according to the relationship between the amount of light received and the formula (8).
(B) Discharge that appears regardless of the amount of light received.

As shown in the matrix of Table 1, the noise discharge of the optical sensor 1 can be categorized by the combination of (a), (b) and (A), (B). In the present invention, the combination of (a) and (A) (aA), the combination of (a) and (B) (aB), the combination of (b) and (A) (bA), (b) and (B) It is highly probable that the combination of (bB) is surely observed.

The discharge of the combination of aA is a normal discharge called "sensitivity" (already incorporated in equation (8)). The discharge of the combination of aB is a discharge irrelevant to the amount of ultraviolet rays triggered by thermions and the like. The discharge of the combination of bA is a discharge that depends on the amount of light among the discharges that are limitedly generated when the drive pulse voltage rises or falls due to the inrush current or the residual ions. The discharge of the combination of bB is a discharge that does not depend on the amount of light among the discharges that are limitedly generated when the drive pulse voltage rises or falls due to the inrush current or the residual ions.

It should be noted that the ones categorized in Table 1 are not all of the UV (ultraviolet) failure modes. For example, there are failure modes not included in Table 1, such as discharge not being cut off and sensitivity wavelengths being different.

The above discharge of aA and the noise discharge of the three types of aB, bA, and bB can be expressed in the form of equation (9).

In equation (9), P _aB is the light receiving amount Q, the discharge probability of aB at the pulse width T, P _bA is the light receiving amount Q, the discharge probability of bA at the pulse width T, P _bB is the light receiving amount Q, bB at the pulse width T. Discharge probability of.

[Calculation method of discharge probabilities P _aB and P _bB]
When the light is not received in the formula (9) (for example, when the shutter is closed), if the light receiving amount Q is 0, the formula (10) is obtained. Here, P ^* is a discharge probability measurement value when the pulse width is T and no light is received.

The measurement is performed with the pulse width T _{1 and the discharge probability 1} P ^* is measured.

Further, the measurement is performed with the pulse width T ₂ (T ₁ ≠ T ₂ ), and the discharge probability ₂ P ^* is measured.

By dividing the equation (11) by the equation (12), the equation (13) is obtained, so that the discharge probability P _aB can be calculated according to the equation (14).

By substituting the equation (14) into the equation (10), the discharge probability P _bB can be calculated according to the equation (15).

Therefore, the discharge probabilities P _aB and P _bB can be obtained by measuring the discharge probabilities ₁ P ^* and ₂ P ^* when the pulse widths T ₁ and T _{2 are not received, respectively.}
In addition, T = T ₁ may be set. The discharge probability P _{bB in} this case can be obtained as in Eq. (16).

Further, T = T ₂ may be set. The discharge probability P _{bB in} this case can be obtained as in Eq. (17).

[Calculation method of received light amount Q]
Next, when the light receiving amount Q is unknown while the optical sensor 1 is capable of daylighting, and the discharge probability _{when the pulse width is T 3 is 3} P, the equation (18) can be obtained from the equation (9).

Similarly, if the discharge probability is _{4 P when the pulse width is T 4} (T ₃ ≠ T ₄ ) while the optical sensor 1 is capable of daylighting, the equation (19) can be obtained from the equation (9).

Dividing equation (18) by equation (19) yields equation (20).

Equation (21) is obtained by modifying equation (20).

_{Substituting the discharge probability P bB} of the equation (15) and the equation (21) into the equation (9) gives the equation (22).

By modifying the equation (22), the light receiving amount Q can be obtained as in the equation (23).

Therefore, even if at least one of the discharge probabilities P _aB and P _bB is unknown, the measurement accompanied by the pulse width adjustment in the state where the optical sensor 1 is shielded from light and the pulse width adjustment in the state where the optical sensor 1 can collect light can be performed. The light receiving amount Q can be obtained by performing the accompanying measurement.

It is necessary to satisfy _{T 1} ≠ T ₂ and T ₃ ≠ T _{4 , but T 1} = T ₃ or T ₁ = T ₄ may be satisfied. Similarly, T ₂ = T ₃ or T ₂ = T ₄ may be set.
Further, when T = T ₁ = T ₃ , the received light amount Q can be obtained as in the equation (24).

Further, when T = T ₁ = T ₄ , the received light amount Q can be obtained as in the equation (25).

Further, when T = T ₂ = T ₃ , the received light amount Q can be obtained as in the equation (26).

Further, when T = T ₂ = T ₄ , the received light amount Q can be obtained as in the equation (27).

[Calculation method of discharge probability P _aA]
Assuming that the discharge probabilities P _{bA are known and the discharge probabilities P aB} , P _bB and the light receiving amount Q can be calculated by the equations (14), (15), and (23), the equations (9) to (28) The discharge probability P _aA can be calculated as in.

When T = T ₃ , the discharge probability P _aA can be obtained as in Eq. (29).

Further, when T = T ₄ , the discharge probability P _aA can be obtained as in the equation (30).

Hereinafter, the operation of the photodetector system of this embodiment will be described in more detail. 3 and 4 are flowcharts for explaining the operation of the photodetection system of this embodiment.
The shutter control unit 23 selectively outputs a shutter open signal (voltage) for opening and closing the shutter 21 to close the shutter (a state in which the optical sensor 1 is shielded from light) and open the shutter (the optical sensor 1 collects light). It is possible to switch between (possible state) and.

In this embodiment, the shutter open signal is not output in the initial state at the time of shipping inspection of the photodetection system or at the site where the photodetection system is installed. Therefore, the shutter drive unit 22 keeps the shutter 21 closed (step S100 in FIG. 3). As a result, the light from the light source 100 is blocked by the shutter 21, and the light incident on the optical sensor 1 is blocked.

The discharge probability calculation unit 202 initializes the variable i for pulse width control to 1 (step S101 in FIG. 3). When the variable i is smaller than 3 (YES in step S102 in FIG. 3), the discharge probability calculation unit 202 instructs the rectangular pulse generation unit 17 to start applying the drive pulse voltage PM.

In response to the instruction from the discharge probability calculation unit 202, the square pulse generation unit 17 sets the pulse width of the square pulse PS to a predetermined value _Ti = T ₁ . By setting this pulse width, the applied voltage generation circuit 12 applies _{the drive pulse voltage PM having the pulse width Ti} = T ₁ between the pair of terminals 1a and 1b of the optical sensor 1 (step S103 in FIG. 3).

The discharge determination unit 201 compares the detection voltage Vpv from the current detection circuit 15 with the predetermined threshold voltage Vth, and determines that the optical sensor 1 has been discharged when the detection voltage Vpv exceeds the threshold voltage Vth. .. When the discharge determination unit 201 determines that the optical sensor 1 has been discharged, the discharge determination unit 201 counts the number of discharges n _i ^* = n ₁ ^* with this as one (step S104 in FIG. 3). The initial values of the number of discharges n ₁ ^* and the number of times the drive pulse voltage PM is applied N ₁ ^{* are both 0.} In this way, the processes of steps S103 and S104 are repeatedly executed.

The pulse application number integrating unit 204 counts the number of times the drive pulse voltage PM is applied N _i ^* = N ₁ ^* by counting the rectangular pulse PS output from the rectangular pulse generation unit 17.
The application number determination unit 205 compares the application frequency N _i ^* = N ₁ ^* of the drive pulse voltage PM with the predetermined number Nth ^* .

Discharge probability calculation unit 202, a step S103 the number of applications of the driving pulse voltage PM from at start of the application of the pulse width T _i = T ₁ of the drive pulse voltage PM by N _i ^* = N ₁ ^* exceeds a predetermined number Nth ^* When the application number determination unit 205 determines (YES in step S105 of FIG. 3), the number of times the drive pulse voltage PM is applied N _i ^* = N ₁ ^* and the number of discharges detected by the discharge determination unit 201 n _i ^* = Based on n ₁ ^* _{, the discharge probability 1} P ^* is calculated by the equation (31) (step S106 in FIG. 3).
₁ P ^* = n ₁ ^* / N ₁ ^*・ ・ ・ (31)

After calculating the discharge probability ₁ P ^* , the discharge probability calculation unit 202 increases the variable i for pulse width control by 1 (step S107 in FIG. 3). When the variable i is smaller than 3 (YES in step S102), the discharge probability calculation unit 202 instructs the rectangular pulse generation unit 17 to start applying the drive pulse voltage PM again.

In response to the instruction from the discharge probability calculation unit 202, the square pulse generation unit 17 temporarily stops the output of the square wave PS, and then sets the pulse width of the square wave PS to a predetermined value T _i = T ₂ (T ₁ ≠ T). Set to _2). By setting this pulse width, the applied voltage generation circuit 12 applies _{the drive pulse voltage PM of the pulse width Ti} = T ₂ between the pair of terminals 1a and 1b of the optical sensor 1 (step S103).

Similarly to the above, the discharge determination unit 201 determines that the optical sensor 1 has been discharged when the detection voltage Vpv from the current detection circuit 15 exceeds the threshold voltage Vth, and _{increases the number of discharges n i} ^* = n ₂ ^* by 1. (Step S104). The initial values of the number of discharges n ₂ ^* and the number of times the drive pulse voltage PM is applied N ₂ ^{* are both 0.} In this way, the processes of steps S103 and S104 are repeatedly executed.

Discharge probability calculation unit 202 includes a pulse width T _i = the number of applications of the driving pulse voltage PM from time of application start of T ₂ of the drive pulse voltage PM N _i ^* = N ₂ ^* in step S103 exceeds a predetermined number Nth ^* When the application number determination unit 205 determines (YES in step S105), the number of times the drive pulse voltage PM is applied N _i ^* = N ₂ ^* and the number of discharges detected by the discharge determination unit 201 n _i ^* = n ₂ ^{Based on *} _{, the discharge probability 2} P ^* is calculated by the equation (32) (step S106).
₂ P ^* = n ₂ ^* / N ₂ ^*・ ・ ・ (32)

After calculating the discharge probability ₂ P ^* , the discharge probability calculation unit 202 increases the variable i for pulse width control by 1 (step S107). When the variable i reaches 3 (NO in step S102), the discharge probability calculation unit 202 instructs the square wave generation unit 17 to start applying the drive pulse voltage PM again.

In response to the instruction from the discharge probability calculation unit 202, the square pulse generation unit 17 temporarily stops the output of the square wave PS, and then sets the pulse width of the square wave PS to a predetermined value T. By setting this pulse width, the applied voltage generation circuit 12 applies the drive pulse voltage PM of the pulse width T between the pair of terminals 1a and 1b of the optical sensor 1 (step S108 in FIG. 3).

Similarly to the above, the discharge determination unit 201 determines that the optical sensor 1 has been discharged when the detection voltage Vpv from the current detection circuit 15 exceeds the threshold voltage Vth, and ^{increases the number of discharges n *} by 1 (step S109 in FIG. 3). ). The initial values of the ^{number of discharges n *} and the number of times the drive pulse voltage PM is applied N ^{* are both 0.} In this way, the processes of steps S108 and S109 are repeatedly executed.

When the discharge probability calculation unit 202 determines that the number of ^{times N *} of the drive pulse voltage PM applied from the start of application of the drive pulse voltage PM of the pulse width T in step S108 exceeds a ^{predetermined number Nth * by the discharge probability calculation unit 205. (YES in step S110 of FIG. 3), the discharge probability P *} is calculated by the equation (33) based on the ^{number of times N *} of the drive pulse voltage PM applied at this time and the number of times of ^{discharge n *} detected by the discharge determination unit 201. (Step S111 in FIG. 3).
P ^* = n ^* / N ^* ... (33)

In the sensitivity parameter storage unit 19, as known sensitivity parameters of the optical sensor 1, the reference light receiving amount Q _{0 of the optical sensor 1, the reference pulse width T 0} of the drive pulse voltage PM, and the discharge probability P bA of the non-regular discharge are _stored. Is stored in advance. Either one of the above pulse widths T ₁ and T ₂ (T ₁ ≠ T ₂ ) may be the same as the _{reference pulse width T 0.}

As described above, the discharge probability P _bA is due to noise components other than discharge due to the photoelectric effect of the optical sensor 1, which are generated independently of the pulse width of the drive pulse voltage PM and depending on the amount of light received by the optical sensor 1. The probability of discharge.
The sensitivity parameter stored in the sensitivity parameter storage unit 19 shall be measured in advance, for example, in the shipping inspection of the photodetection system.

_{The discharge probability calculation unit 203 determines the discharge probability 1} P ^* , calculated by the discharge probability calculation unit 202 when the measurement in the light-shielded state of the optical sensor 1 is completed, that is, when ^{the calculation of the discharge probability P * is completed.} _{Based on 2} P ^* _{, the pulse widths T 1} and T ₂ of the drive pulse voltage PM when the discharge probabilities ₁ P ^* and ₂ P ^* _{are obtained, and the parameter T 0} stored in the sensitivity parameter storage unit 19. _{, The discharge probability P aB} of the non-regular discharge is calculated by the equation (14) (step S112 in FIG. 3). As described above, the discharge probability P _aB is due to a noise component other than the discharge due to the photoelectric effect of the optical sensor 1, which is generated depending on the pulse width of the drive pulse voltage PM and not depending on the amount of light received by the optical sensor 1. The probability of discharge.

Subsequently, the discharge probability calculation unit 203 obtains the discharge probabilities ₁ P ^* , ₂ P ^* , P ^* calculated by the discharge probability calculation unit 202, and the drive pulse voltage when the discharge probabilities ₁ P ^* , ₂ P ^{* are obtained.} Based on the pulse widths T ₁ and T _{2 of} PM and the pulse width T of the drive pulse voltage PM when the discharge probability P ^* _{is obtained, the discharge probability P bB} of non-normal discharge is calculated by Eq. (15). (FIG. 3, step S113). The discharge probability P _bB is the probability of discharge due to a noise component other than the discharge due to the photoelectric effect of the optical sensor 1, which is generated independently of the pulse width of the drive pulse voltage PM and the amount of light received by the optical sensor 1 as described above. ..

Next, the shutter control unit 23 outputs a shutter open signal when the measurement in the light-shielded state of the optical sensor 1 is completed.
The shutter drive unit 22 opens the shutter 21 when a shutter open signal is output from the shutter control unit 23 (step S114 in FIG. 3). When the shutter 21 is opened, the optical sensor 1 is in a state where it can collect light. The light from the light source 100 is incident on the optical sensor 1.

When the variable i is smaller than 5 (YES in step S115 in FIG. 3), the discharge probability calculation unit 202 instructs the rectangular pulse generation unit 17 to start applying the drive pulse voltage PM again.

In response to the instruction from the discharge probability calculation unit 202, the square pulse generation unit 17 sets the pulse width of the square pulse PS to a predetermined value _Ti = T ₃ . By setting this pulse width, the applied voltage generation circuit 12 applies _{the drive pulse voltage PM of the pulse width Ti} = T ₃ between the pair of terminals 1a and 1b of the optical sensor 1 (step S116 in FIG. 3).

Similarly to the above, the discharge determination unit 201 determines that the optical sensor 1 has been discharged when the detection voltage Vpv from the current detection circuit 15 exceeds the threshold voltage Vth, and _{increases the number of discharges n i} = n ₃ by 1 (FIG. 3 steps S117). The initial values of the _{number of discharges n 3} and the number of times the drive pulse voltage PM is applied N _{3 are both 0.} In this way, the processes of steps S116 and S117 are repeatedly executed.

The discharge probability calculation unit 202 determines that the number of applications of the drive pulse voltage PM from the start of application of the drive pulse voltage PM of the _{pulse width T i} = T _{3 in step S116 N i} = N ₃ exceeds a predetermined number Nth. When the unit 205 determines (YES in step S118 of FIG. 3), the number of times the drive pulse voltage PM is applied N _i = N _{3 at this time and the number of discharges n i} = n ₃ detected by the discharge determination unit 201. _{, The discharge probability 3} P is calculated by the equation (34) (step S119 in FIG. 3).
₃ P = n ₃ / N ₃ ... (34)

After calculating the discharge probability ₃ P, discharge probability calculation unit 202, a variable i for the pulse width control is increased by one (Fig. 3 step S120). When the variable i is smaller than 5 (YES in step S115), the discharge probability calculation unit 202 instructs the rectangular pulse generation unit 17 to start applying the drive pulse voltage PM again.

In response to the instruction from the discharge probability calculation unit 202, the square pulse generation unit 17 temporarily stops the output of the square wave PS, and then sets the pulse width of the square wave PS to a predetermined value T _i = T ₄ (T ₃ ≠ T). ₄ ) Set to. By setting this pulse width, the applied voltage generation circuit 12 applies _{the drive pulse voltage PM having the pulse width Ti} = T ₄ between the pair of terminals 1a and 1b of the optical sensor 1 (step S116).

Similarly to the above, the discharge determination unit 201 determines that the optical sensor 1 has been discharged when the detection voltage Vpv from the current detection circuit 15 exceeds the threshold voltage Vth, and _{increases the number of discharges n i} = n ₄ by 1 (step). S117). The initial values of the _{number of discharges n 4} and the number of times the drive pulse voltage PM is applied N _{4 are both 0.} In this way, the processes of steps S116 and S117 are repeatedly executed.

The discharge probability calculation unit 202 determines that the number of applications of the drive pulse voltage PM from the start of application of the drive pulse voltage PM of the _{pulse width T i} = T _{4 in step S116 N i} = N ₄ exceeds a predetermined number Nth. When the unit 205 determines (YES in step S118), the equation is based on the _{number of times the drive pulse voltage PM is applied N i} = N _{4 and the number of discharges n i} = n ₄ detected by the discharge determination unit 201. The discharge probability ₄ P is calculated according to (35) (step S119).
₄ P = n ₄ / N ₄ ... (35)

After calculating the discharge probability ₄ P, discharge probability calculation unit 202, a variable i for the pulse width control is increased by one (step S120). When the variable i reaches 5 (NO in step S115), the discharge probability calculation unit 202 instructs the square wave generation unit 17 to start applying the drive pulse voltage PM again.

In response to the instruction from the discharge probability calculation unit 202, the square pulse generation unit 17 temporarily stops the output of the square wave PS, and then sets the pulse width of the square wave PS to a predetermined value T. By setting this pulse width, the applied voltage generation circuit 12 applies the drive pulse voltage PM of the pulse width T between the pair of terminals 1a and 1b of the optical sensor 1 (step S121 in FIG. 3).

Similarly to the above, the discharge determination unit 201 determines that the optical sensor 1 has been discharged when the detection voltage Vpv from the current detection circuit 15 exceeds the threshold voltage Vth, and increases the number of discharges n by 1 (step S122 in FIG. 3). .. The initial values of the number of discharges n and the number of times the drive pulse voltage PM is applied N are both 0. In this way, the processes of steps S121 and S122 are repeatedly executed.

When the discharge probability calculation unit 202 determines that the number of times N of the drive pulse voltage PM applied from the start of application of the drive pulse voltage PM of the pulse width T in step S121 exceeds a predetermined number Nth (FIG. FIG. YES in 3 steps S123), the discharge probability P is calculated by the equation (36) based on the number of times N of application of the drive pulse voltage PM at this time and the number of times of discharge n detected by the discharge determination unit 201 (FIG. 3 step). S124).
P = n / N ... (36)

_{The light receiving amount calculation unit 206 has the discharge probabilities 3} P and ₄ P calculated by the discharge probability calculation unit 202 when the measurement in the state where the optical sensor 1 can collect light is completed, that is, when the calculation of the discharge probability P is completed. When is greater than 0 and less than 1 (YES in step S125 of FIG. 4), the discharge probabilities P ^* , ₁ P ^* , ₂ P ^* , P, ₃ P, ₄ P calculated by the discharge probability calculation unit 202, and the discharge. a pulse width T ₁ of the drive pulse voltage PM when calculated probability ₁ P ^*, the pulse width T ₂ of the drive pulse voltage PM when seeking discharge probability ₂ P ^*, when the calculated discharge probability ₃ P The pulse width T ₃ of the drive pulse voltage PM, the pulse width T ₄ of the drive pulse voltage PM when the discharge probability ₄ P is obtained, and the pulse width T of the drive pulse voltage PM when the discharge probabilities P ^* and P are obtained. _{And the parameters Q 0} and P _bA stored in the sensitivity parameter storage unit 19, the received light amount Q is calculated by the equation (23) (FIG. 4, step S126).

_{Further, when at least one of the discharge probabilities 3} P and ₄ P calculated by the discharge probability calculation unit 202 is 0 (NO in step S125), the light receiving amount calculation unit 206 sets the light receiving amount Q to 0 or sets it to 0. Exception processing is performed so that the received light amount Q cannot be calculated (step S127 in FIG. 4). _{Further, when at least one of the discharge probabilities 3} P and ₄ P is 1 (NO in step S125), the light receiving amount calculation unit 206 performs exception processing for disabling the light receiving amount Q (step S127).

Next, the discharge probability calculation unit 208 is calculated by the discharge probability P calculated by the discharge probability calculation unit 202, the pulse width T of the drive pulse voltage PM when the discharge probability P is obtained, and the discharge probability calculation unit 203. Discharge probabilities P _aB , P _bB , the light receiving amount Q calculated by the light receiving amount calculation unit 206, and _{the discharge probabilities Q 0} , T ₀ , P _{bA stored in the sensitivity parameter storage unit 19.} P _aA is calculated by the equation (28) (FIG. 4, step S128). The discharge probability P _aA is the discharge probability of normal discharge when the pulse width of the drive pulse voltage PM is the reference pulse width T ₀ and the light reception amount of the optical sensor 1 is the reference light reception amount Q _{0 as described above.}

The light receiving amount determination unit 207 compares the light receiving amount Q calculated by the light receiving amount calculating unit 206 with the predetermined light receiving amount threshold Qth (step S129 of FIG. 4), and when the light receiving amount Q exceeds the light receiving amount threshold Qth ( YES in step S129), it is determined that there is a flame (FIG. 4, step S130). Further, when the light receiving amount Q is equal to or less than the light receiving amount threshold Qth (NO in step S129), the light receiving amount determining unit 207 determines that there is no flame (FIG. 4, step S131).

As can be seen from the above explanation, in this embodiment, the discharge probabilities P _aB and P _bB of the non-regular discharge, the light receiving amount Q, and the discharge probabilities P _aA of the normal discharge can be calculated and obtained. It is possible to accurately detect the presence or absence of a flame from the received light amount Q. _{Further, since it is considered that the discharge probabilities P aB} , P _bB , and P _aA change as the optical sensor 1 deteriorates, the life of the optical sensor 1 is determined based on the received light amount Q and the discharge probabilities P _aB , P _bB , and P _aA. Can be realized. As a result, in this embodiment, it is possible to reduce the possibility of erroneously determining the life of the optical sensor 1.

As described above, in this embodiment, T ₁ = T ₃ may be set. In particular, when T = T ₁ = T ₃ , the processes shown in FIGS. 5 and 6 can be performed instead of the processes shown in FIGS. 3 and 4.
The processing of steps S100 to S107 of FIG. 5 is as described with reference to FIG. When the variable i reaches 3 (NO in step S102 of FIG. 5), the discharge probability calculation unit 203 calculates the discharge probability P _aB of the non-normal discharge (step S112 of FIG. 5).

The discharge probability calculation unit 203, the discharge probability calculating unit 202 discharge probability ₁ calculated by P ^*, ₂ and P ^*, discharge probability ₁ P ^*, ₂ P ^* to the pulse width of the drive pulse voltage PM when determined Based on T ₁ and T _{2 , the discharge probability P bB} of the non-normal discharge is calculated by the equation (16) (step S113a in FIG. 5). The processing of steps S114 to S120 of FIG. 5 is as described with reference to FIG.

When the variable i reaches 5 (NO in step S115 in FIG. 5), the light receiving amount calculation unit 206 indicates that the discharge probabilities ₃ P and ₄ P calculated by the discharge probability calculation unit 202 are greater than 0 and less than 1 ( YES) in step S125 of FIG. 6, the discharge probabilities ₁ P ^* , ₂ P ^* , ₃ P, ₄ P and the discharge probabilities ₁ P ^* , ₂ P ^* , ₃ P, ₄ P calculated by the discharge probability calculation unit 202 are set. _{Based on the pulse widths T 1} , T ₂ , T ₃ , and T ₄ of the drive pulse voltage PM at the time of determination _{and the parameters Q 0} and P _bA stored in the sensitivity parameter storage unit 19, the equation (24) is used. The received light amount Q is calculated (step S126a in FIG. 6). The process of step S127 in FIG. 6 is as described in FIG.

The discharge probability calculation unit 208 is calculated by the discharge probability _{3 P calculated by the discharge probability calculation unit 202, the pulse width T 3} of the drive pulse voltage PM when the discharge probability ₃ P is obtained, and the discharge probability calculation unit 203. Discharge probabilities P _aB , P _bB , the light receiving amount Q calculated by the light receiving amount calculation unit 206, and _{the discharge probabilities Q 0} , T ₀ , P _{bA stored in the sensitivity parameter storage unit 19.} P _aA is calculated by the equation (29) (step S128a in FIG. 6). The processing of steps S129 to S131 in FIG. 6 is as described in FIG.

The case of T = T ₁ = T _{4 is the same as} the case of T = T ₁ = T ₃ . When T = T ₁ = T ₄ , the discharge probability calculation unit 203 may calculate the discharge probability P _bB by the equation (16) in step S113a of FIG. Further, the light receiving amount calculation unit 206 may calculate the light receiving amount Q by the equation (25) in step S126a of FIG. The discharge probability calculation unit 208 may calculate the discharge probability P _aA by the equation (30) in step S128a of FIG.

The case of T = T ₂ = T _{3 is the same as} the case of T = T ₁ = T ₃ . When T = T ₂ = T ₃ , the discharge probability calculation unit 203 may calculate the discharge probability P _bB by the equation (17) in step S113a of FIG. The light receiving amount calculation unit 206 may calculate the light receiving amount Q by the equation (26) in step S126a of FIG. The discharge probability calculation unit 208 may calculate the discharge probability P _aA by the equation (29) in step S128a of FIG.

The case of T = T ₂ = T _{4 is the same as} the case of T = T ₁ = T ₃ . When T = T ₂ = T ₄ , the discharge probability calculation unit 203 may calculate the discharge probability P _bB by the equation (17) in step S113a of FIG. The light receiving amount calculation unit 206 may calculate the light receiving amount Q by the equation (27) in step S126a of FIG. The discharge probability calculation unit 208 may calculate the discharge probability P _aA by the equation (30) in step S128a of FIG.

In the example of FIG. 3, (when the pulse width T ₁ in step S103 to S105) the shutter closed state (state in which the optical sensor 1 is light) the first state, the pulse in the second state (step S103 to S105 When the width T ₂ ), the third state (steps S108 to S110) is set, and the shutter open state (the state where the optical sensor 1 can collect light) is set to the fourth state (when the _{pulse width T 3 in steps S116 to S118).} ), The fifth state ( _{when the pulse width T 4} in steps S116 to S118), and the sixth state (steps S121 to S123).

Further, in the example of FIG. 5, (when in step S103~S105 pulse width T ₁₎ shutter closed state (state in which the optical sensor 1 is light) a first state, a second state (step S103~S105 In the pulse width T ₂ ), the shutter open state (the state in which the optical sensor 1 can collect light) is the third state ( _{when the pulse width T 3} is in steps S116 to S118), and the fourth state (step S116). (When the pulse width is T _{4 in} ~ S118).

In this embodiment, the present invention is applied to a photodetection system with a shutter mechanism, but it is also possible to apply the present invention to a photodetection system without a shutter mechanism. In this case, when performing the shipping inspection of the optical detection system or the processing of steps S101 to S113 of FIG. 3 or the processing of steps S101 to S107, S112, S113a of FIG. 5 at the site where the optical detection system is installed, For example, by attaching a cover to the optical sensor 1, the optical sensor 1 may be shielded from light. At this time, a signal indicating that the optical sensor 1 is in a light-shielded state is input to the photodetection system by, for example, a user's operation. As a result, the arithmetic unit 3 of the photodetection system performs the processes of steps S101 to S113 of FIG. 3 or the processes of steps S101 to S107, S112, and S113a of FIG.

Further, when the processing of steps S115 to S131 of FIGS. 3 and 4 or the processing of steps S115 to S120, S125, S126a, S127 to S131 of FIGS. 5 and 6 is performed, the optical sensor 1 is shielded from light. It may be released so that the optical sensor 1 can take light. At this time, a signal indicating that the photosensor 1 is in a state where light can be collected is input to the photodetection system by, for example, a user's operation. As a result, the arithmetic unit 3 of the photodetection system performs the processing of steps S115 to S131 of FIGS. 3 and 4, or the processing of steps S115 to S120, S125, S126a, and S127 to S131 of FIGS. 5 and 6.

In this embodiment, the case where the light source 100 is a flame is described as an example, but the photodetection system of the present invention can be applied to a light source 100 other than the flame.

The sensitivity parameter storage unit 19 and the central processing unit 20 described in this embodiment can be realized by a computer equipped with a CPU (Central Processing Unit), a storage device, and an interface, and a program for controlling these hardware resources. can.

A configuration example of this computer is shown in FIG. The computer includes a CPU 300, a storage device 301, and an interface device (I / F) 302. The applied voltage generation circuit 12, the rectangular pulse generation unit 17, the A / D conversion unit 18, the shutter control unit 23, and the like are connected to the I / F 302. In such a computer, a program for realizing the light receiving amount measuring method of the present invention is stored in the storage device 301. The CPU 300 executes the process described in this embodiment according to the program stored in the storage device 301.

The present invention can be applied to flame detection systems. The present invention can also be applied to the detection of light other than flame.

1 ... optical sensor, 2 ... external power supply, 3 ... computing device, 11 ... power supply circuit, 12 ... applied voltage generation circuit, 13 ... trigger circuit, 14 ... voltage dividing resistor, 15 ... current detection circuit, 16 ... processing circuit, 17 ... Rectangular pulse generator, 18 ... A / D conversion unit, 19 ... Sensitivity parameter storage unit, 20 ... Central processing unit, 21 ... Shutter, 22 ... Shutter drive unit, 23 ... Shutter control unit, 100 ... Light source, 201 ... Discharge Judgment unit, 202, 203, 208 ... Discharge probability calculation unit, 204 ... Pulse application number integration unit, 205 ... Application number determination unit, 206 ... Light receiving amount calculation unit, 207 ... Light receiving amount determination unit.

Claims (11)

An optical sensor configured to detect the light emitted by a light source,
An applied voltage generator configured to periodically apply a drive pulse voltage to the electrodes of this optical sensor,
A current detection unit configured to detect the discharge current of the optical sensor, and
A discharge determination unit configured to detect the discharge of the optical sensor based on the discharge current detected by the current detection unit, and a discharge determination unit.
A first state in which the optical sensor is shielded from light, a second state in which the optical sensor is shielded from light and the pulse width of the drive pulse voltage is different from the first state, and the optical sensor is shielded from light and The drive pulse voltage has the same pulse width as either of the first and second states, or a third state different from the first and second states, and the optical sensor can collect light and the drive pulse. The voltage pulse width is the same as either the first or second state, or the fourth state is different from the first and second states, and the optical sensor can collect light and the drive pulse voltage pulse. The applied voltage for each of the fifth state in which the width is different from the fourth state and the sixth state in which the optical sensor can collect light and the pulse width of the drive pulse voltage is the same as the third state. A first discharge probability configured to calculate the discharge probability based on the number of times the drive pulse voltage is applied by the generation unit and the number of discharges detected by the discharge determination unit during the application of the drive pulse voltage. Calculation part and
As known sensitivity parameters of the optical sensor, the reference light receiving amount of the optical sensor, the reference pulse width of the driving pulse voltage, and the light receiving amount of the optical sensor that are generated independently of the pulse width of the driving pulse voltage. A storage unit configured to store in advance the discharge probability of a first-class non-regular discharge due to a noise component other than the discharge due to the photoelectric effect of the optical sensor, which is generated depending on the light sensor.
The sensitivity parameters stored in the storage unit, the discharge probability calculated by the first discharge probability calculation unit in the first, second, and third states, and the first, second, and third states. Due to the noise component, which is generated depending on the pulse width of the drive pulse voltage and not depending on the amount of light received by the optical sensor, based on the pulse width of the drive pulse voltage in the state of 3. Discharge of the third type of non-regular discharge due to the noise component, which occurs independently of the discharge probability of the second type of non-regular discharge, the pulse width of the drive pulse voltage, and the amount of light received by the optical sensor. A second discharge probability calculation unit configured to calculate the probability and
Sensitivity parameters stored in the storage unit and discharge probabilities calculated by the first discharge probability calculation unit in the first, second, third, fourth, fifth, and sixth states. , Based on the pulse width of the drive pulse voltage in the first, second, third, fourth, fifth, and sixth states, in the fourth, fifth, and sixth states. A light receiving amount calculation unit configured to calculate the light receiving amount of the optical sensor, and a light receiving amount calculation unit.
The sensitivity parameter stored in the storage unit, the discharge probability calculated by the first discharge probability calculation unit in the sixth state, and the pulse of the drive pulse voltage in the sixth state. Based on the width, the discharge probability calculated by the second discharge probability calculation unit, and the light reception amount calculated by the light reception amount calculation unit, the pulse width of the drive pulse voltage is the reference pulse width and the light. A light detection system including a third discharge probability calculation unit configured to calculate a discharge probability of a normal discharge when the light reception amount of the sensor is the reference light reception amount. In the light detection system according to claim 1,
The second discharge probability calculation unit sets the reference pulse width of the drive pulse voltage to T ₀ , and sets the discharge probability calculated by the first discharge probability calculation unit in the first state by ₁ P ^* . The discharge probability calculated by the first discharge probability calculation unit in the second state is ₂ P ^* , and the discharge probability calculated by the first discharge probability calculation unit in the third state is P. ^* , The pulse width of the drive pulse voltage in the first state is T ₁ , the pulse width of the drive pulse voltage in the second state is T ₂ (T ₁ ≠ T ₂ ), and the third When the pulse width of the drive pulse voltage in the state of is T, the discharge probability of the second type non-normal discharge is P _aB , and the discharge probability of the third type non-regular discharge is P _bB .

To calculate _{the discharge probability P aB} of the second type of non-regular discharge.

The optical detection system and calculates the discharge probability P _bB discharge of the third type of non-regular. In the photodetection system according to claim 1 or 2.
The light receiving amount calculation unit sets the reference light receiving amount of the optical sensor to Q ₀ , the discharge probability of the first type of non-regular discharge to P _bA , and the first discharge probability calculation unit in the first state. The discharge probability calculated by ₁ P ^* , the discharge probability calculated by the first discharge probability calculation unit in the second state is ₂ P ^* , and the first in the third state. the discharge probability calculated by the discharge probability calculation unit P ^*, the fourth state the first discharge probability ₃ P the calculated discharge probability by the calculating unit when, during the fifth state the The discharge probability calculated by the discharge probability calculation unit of 1 is ₄ P, the discharge probability calculated by the first discharge probability calculation unit in the sixth state is P, and the discharge probability in the first state is P. The pulse width of the drive pulse voltage is T ₁ , the pulse width of the drive pulse voltage in the second state is T ₂ (T ₁ ≠ T ₂ ), and the pulse of the drive pulse voltage in the fourth state. The width is T ₃ , the pulse width of the drive pulse voltage in the fifth state is T ₄ (T ₃ ≠ T 4), and the pulse width of the drive pulse voltage in the third and sixth states is _{T 4.} When T, the amount of light received by the optical sensor in the fourth, fifth, and sixth states is Q,

A light detection system characterized in that the light receiving amount Q is calculated by the above method. In the photodetection system according to any one of claims 1 to 3.
The third discharge probability calculation unit sets the reference light receiving amount of the optical sensor to Q ₀ , the reference pulse width of the drive pulse voltage to T ₀ , the discharge probability of the first type of non-normal discharge to P _bA , and the above. The discharge probability of the second type of non-normal discharge is P _aB , the discharge probability of the third type of non-normal discharge is P _bB , and it is calculated by the first discharge probability calculation unit in the sixth state. The discharge probability is P, the amount of light received by the optical sensor in the fourth, fifth, and sixth states is Q, the pulse width of the drive pulse voltage in the sixth state is T, and the normal When the discharge probability of discharge is _PaA ,

The optical detection system and calculates the discharge probability P _aA of discharge of said normal. An optical sensor configured to detect the light emitted by a light source,
An applied voltage generator configured to periodically apply a drive pulse voltage to the electrodes of this optical sensor,
A current detection unit configured to detect the discharge current of the optical sensor, and
A discharge determination unit configured to detect the discharge of the optical sensor based on the discharge current detected by the current detection unit, and a discharge determination unit.
A first state in which the optical sensor is shielded from light, a second state in which the optical sensor is shielded from light and the pulse width of the drive pulse voltage is different from the first state, and the optical sensor can collect light. The drive pulse voltage has the same pulse width as either of the first and second states, or a third state different from the first and second states, and the optical sensor can collect light and the drive. Each of the fourth states in which the pulse width of the pulse voltage is different from the third state is detected by the discharge determination unit during the application of the drive pulse voltage and the number of times the drive pulse voltage is applied by the applied voltage generation unit. A first discharge probability calculation unit configured to calculate the discharge probability based on the number of discharges performed, and
As known sensitivity parameters of the optical sensor, the reference light receiving amount of the optical sensor, the reference pulse width of the driving pulse voltage, and the light receiving amount of the optical sensor that are generated independently of the pulse width of the driving pulse voltage. A storage unit configured to store in advance the discharge probability of a first-class non-regular discharge due to a noise component other than the discharge due to the photoelectric effect of the optical sensor, which is generated depending on the light sensor.
Sensitivity parameters stored in the storage unit, discharge probabilities calculated by the first discharge probability calculation unit in the first and second states, and discharge probabilities in the first and second states. A second type of non-normal due to the noise component, which is generated depending on the pulse width of the drive pulse voltage and not depending on the amount of light received by the optical sensor, based on the pulse width of the drive pulse voltage. To calculate the discharge probability of the third type of non-regular discharge due to the noise component, which is generated independently of the pulse width of the drive pulse voltage and the amount of light received by the optical sensor. The second discharge probability calculation unit configured in
The sensitivity parameters stored in the storage unit, the discharge probability calculated by the first discharge probability calculation unit in the first, second, third, and fourth states, and the first and first discharge probabilities. Light reception configured to calculate the light reception amount of the optical sensor in the third and fourth states based on the pulse width of the drive pulse voltage in the second, third, and fourth states. Quantity calculation unit and
Sensitivity parameters stored in the storage unit, discharge probabilities calculated by the first discharge probability calculation unit in the third and fourth states, and discharge probabilities in the third and fourth states. The pulse width of the drive pulse voltage is the pulse width of the drive pulse voltage based on the pulse width of the drive pulse voltage, the discharge probability calculated by the second discharge probability calculation unit, and the light reception amount calculated by the light reception amount calculation unit. An optical detection system including a third discharge probability calculation unit configured to calculate a discharge probability of a normal discharge when the light receiving amount of the optical sensor is the reference light receiving amount with a reference pulse width. .. In the light detection system according to claim 5,
The second discharge probability calculation unit sets the reference pulse width of the drive pulse voltage to T ₀ , and sets the discharge probability calculated by the first discharge probability calculation unit in the first state by ₁ P ^* . The discharge probability calculated by the first discharge probability calculation unit in the second state is ₂ P ^* , the pulse width of the drive pulse voltage in the first state is T ₁ , and the second state. When, the pulse width of the drive pulse voltage is T ₂ (T ₁ ≠ T ₂ ), the discharge probability of the second type of non-normal discharge is P _aB , and the discharge probability of the third type of non-regular discharge is When P _bB is used

To calculate _{the discharge probability P aB} of the second type of non-regular discharge.

,or

The optical detection system and calculates the discharge probability P _bB discharge of the third type of non-regular. In the photodetection system according to claim 5 or 6.
The light receiving amount calculation unit sets the reference light receiving amount of the optical sensor to Q ₀ , the discharge probability of the first type of non-regular discharge to P _bA , and the first discharge probability calculation unit in the first state. The discharge probability calculated by ₁ P ^* , the discharge probability calculated by the first discharge probability calculation unit in the second state is ₂ P ^* , and the first in the third state. The discharge probability calculated by the discharge probability calculation unit is ₃ P, the discharge probability calculated by the first discharge probability calculation unit in the _fourth state is 4 P, and the drive in the first state. The pulse width of the pulse voltage is T ₁ , the pulse width of the drive pulse voltage in the second state is T ₂ (T ₁ ≠ T ₂ ), and the pulse width of the drive pulse voltage in the third state. T ₃ , the pulse width of the drive pulse voltage in the fourth state is T ₄ (T ₃ ≠ T ₄ ), and the amount of light received by the optical sensor in the third and fourth states is Q. When you do

,or

,or

,or

A light detection system characterized in that the light receiving amount Q is calculated by the above method. In the photodetection system according to any one of claims 5 to 7.
The third discharge probability calculation unit sets the reference light receiving amount of the optical sensor to Q ₀ , the reference pulse width of the drive pulse voltage to T ₀ , the discharge probability of the first type of non-normal discharge to P _bA , and the above. The discharge probability of the second type of non-normal discharge is P _aB , the discharge probability of the third type of non-normal discharge is P _bB , and it is calculated by the first discharge probability calculation unit in the third state. The discharge probability is ₃ P, the discharge probability calculated by the first discharge probability calculation unit _{in the fourth state is 4} P, and the amount of light received by the optical sensor in the third and fourth states. Q, the pulse width of the drive pulse voltage in the third state is T ₃ , the pulse width of the drive pulse voltage in the fourth state is T ₄ (T ₃ ≠ T ₄ ), and the normal when the discharge of the discharge probability was P _aA,

,or

The optical detection system and calculates the discharge probability P _aA of discharge of said normal. In the photodetection system according to any one of claims 1 to 8.
A light-shielding means provided between the light source and the optical sensor,
A photodetection system further comprising a shutter control unit configured to open and close the light-shielding means to switch between a state in which the light sensor is shielded from light and a state in which the light sensor is capable of daylighting. The first step of periodically applying a drive pulse voltage to the electrodes of the optical sensor when the optical sensor for detecting the light emitted from the light source is in the first shaded state,
The second step of detecting the discharge current of the optical sensor in the first state, and
A third step of detecting the discharge of the optical sensor based on the discharge current in the first state, and
The discharge probability in the first state is calculated based on the number of times the drive pulse voltage is applied by the first step and the number of discharges detected in the third step while the drive pulse voltage is applied. The fourth step to do and
The fifth step of periodically applying the drive pulse voltage to the electrodes of the optical sensor when the optical sensor is shielded from light and the pulse width of the drive pulse voltage is different from the first state in the second state. ,
The sixth step of detecting the discharge current of the optical sensor in the second state, and
A seventh step of detecting the discharge of the optical sensor based on the discharge current in the second state, and
The discharge probability in the second state is calculated based on the number of times the drive pulse voltage is applied by the fifth step and the number of discharges detected in the seventh step while the drive pulse voltage is applied. Eighth step to do and
The optical sensor is shielded from light and the optical sensor is in a third state in which the pulse width of the drive pulse voltage is the same as in either the first or second state or different from the first or second state. The ninth step of periodically applying the drive pulse voltage to the electrodes of
The tenth step of detecting the discharge current of the optical sensor in the third state, and
The eleventh step of detecting the discharge of the optical sensor based on the discharge current in the third state, and
The discharge probability in the third state is calculated based on the number of times the drive pulse voltage is applied in the ninth step and the number of discharges detected in the eleventh step while the drive pulse voltage is applied. The twelfth step to do and
As known sensitivity parameters of the optical sensor, the reference light receiving amount of the optical sensor, the reference pulse width of the drive pulse voltage, and the received light amount of the optical sensor that are generated independently of the pulse width of the drive pulse voltage. Refers to a storage unit that previously stores the discharge probability of the first type of non-regular discharge due to noise components other than the discharge due to the photoelectric effect of the optical sensor, which is stored in this storage unit. The drive is based on the sensitivity parameters, the discharge probabilities calculated in the fourth, eighth, and twelfth steps, and the pulse width of the drive pulse voltage in the first, second, and third states. The discharge probability of the second type of non-regular discharge due to the noise component, which is generated depending on the pulse width of the pulse voltage and not depending on the amount of light received by the optical sensor, and the pulse width of the drive pulse voltage. And the thirteenth step of calculating the discharge probability of the third type of non-regular discharge due to the noise component, which occurs independently of the amount of light received by the optical sensor.
The light is available when the optical sensor is capable of collecting light and the pulse width of the drive pulse voltage is the same as either the first or second state, or is in a fourth state different from the first or second state. The 14th step of periodically applying the drive pulse voltage to the sensor electrodes,
The fifteenth step of detecting the discharge current of the optical sensor in the fourth state, and
The sixteenth step of detecting the discharge of the optical sensor based on the discharge current in the fourth state, and
The discharge probability in the fourth state is calculated based on the number of times the drive pulse voltage is applied in the 14th step and the number of discharges detected in the 16th step while the drive pulse voltage is applied. 17th step to do and
The eighteenth step of periodically applying the drive pulse voltage to the electrodes of the optical sensor when the optical sensor is capable of collecting light and the pulse width of the drive pulse voltage is in a fifth state different from the fourth state. When,
The 19th step of detecting the discharge current of the optical sensor in the fifth state, and
A twentieth step of detecting the discharge of the optical sensor based on the discharge current in the fifth state, and
The discharge probability in the fifth state is calculated based on the number of times the drive pulse voltage is applied in the 18th step and the number of discharges detected in the 20th step while the drive pulse voltage is applied. 21st step to do and
The 22nd step of periodically applying the drive pulse voltage to the electrode of the optical sensor when the optical sensor is capable of collecting light and the pulse width of the drive pulse voltage is the same as the third state in the sixth state. When,
The 23rd step of detecting the discharge current of the optical sensor in the sixth state, and
The 24th step of detecting the discharge of the optical sensor based on the discharge current in the sixth state, and
The discharge probability in the sixth state is calculated based on the number of times the drive pulse voltage is applied in the 22nd step and the number of discharges detected in the 24th step while the drive pulse voltage is applied. 25th step to do and
The sensitivity parameters stored in the storage unit, the discharge probabilities calculated in the fourth, eighth, twelfth, 17th, 21st, and 25th steps, and the first, second, third, and second steps. The 26th calculation of the amount of light received by the optical sensor in the fourth, fifth, and sixth states based on the pulse width of the drive pulse voltage in the fourth, fifth, and sixth states. Steps and
The sensitivity parameter stored in the storage unit, the discharge probability calculated in the 25th step, the pulse width of the drive pulse voltage in the sixth state, and the discharge calculated in the 13th step. Based on the probability and the light receiving amount calculated in the 26th step, the discharge of the normal discharge when the pulse width of the driving pulse voltage is the reference pulse width and the light receiving amount of the optical sensor is the reference light receiving amount. A method for calculating a discharge probability of an optical detection system, which comprises a 27th step of calculating a probability. The first step of periodically applying a drive pulse voltage to the electrodes of the optical sensor when the optical sensor for detecting the light emitted from the light source is in the first shaded state,
The second step of detecting the discharge current of the optical sensor in the first state, and
A third step of detecting the discharge of the optical sensor based on the discharge current in the first state, and
The discharge probability in the first state is calculated based on the number of times the drive pulse voltage is applied by the first step and the number of discharges detected in the third step while the drive pulse voltage is applied. The fourth step to do and
The fifth step of periodically applying the drive pulse voltage to the electrodes of the optical sensor when the optical sensor is shielded from light and the pulse width of the drive pulse voltage is different from the first state in the second state. ,
The sixth step of detecting the discharge current of the optical sensor in the second state, and
A seventh step of detecting the discharge of the optical sensor based on the discharge current in the second state, and
The discharge probability in the second state is calculated based on the number of times the drive pulse voltage is applied by the fifth step and the number of discharges detected in the seventh step while the drive pulse voltage is applied. Eighth step to do and
As known sensitivity parameters of the optical sensor, the reference light receiving amount of the optical sensor, the reference pulse width of the drive pulse voltage, and the received light amount of the optical sensor that are generated independently of the pulse width of the drive pulse voltage. Refers to a storage unit that previously stores the discharge probability of the first type of non-regular discharge due to noise components other than the discharge due to the photoelectric effect of the optical sensor, which is stored in this storage unit. Based on the sensitivity parameter, the discharge probability calculated in the 4th and 8th steps, and the pulse width of the drive pulse voltage in the 1st and 2nd states, the pulse width of the drive pulse voltage is determined. The discharge probability of the second type of non-regular discharge due to the noise component, which is generated depending on and does not depend on the amount of light received by the optical sensor, the pulse width of the drive pulse voltage, and the light received by the optical sensor. The ninth step of calculating the discharge probability of the third type of non-normal discharge due to the noise component, which occurs independently of the amount, and
The light is available when the optical sensor is capable of collecting light and the pulse width of the drive pulse voltage is the same as either the first or second state, or is in a third state different from the first or second state. The tenth step of periodically applying the drive pulse voltage to the sensor electrodes,
The eleventh step of detecting the discharge current of the optical sensor in the third state, and
A twelfth step of detecting the discharge of the optical sensor based on the discharge current in the third state, and
The discharge probability in the third state is calculated based on the number of times the drive pulse voltage is applied in the tenth step and the number of discharges detected in the twelfth step while the drive pulse voltage is applied. 13th step to do and
A fourteenth step of periodically applying a drive pulse voltage to an electrode of the optical sensor when the optical sensor is capable of collecting light and the pulse width of the drive pulse voltage is in a fourth state different from the third state. When,
The fifteenth step of detecting the discharge current of the optical sensor in the fourth state, and
The sixteenth step of detecting the discharge of the optical sensor based on the discharge current in the fourth state, and
The discharge probability in the fourth state is calculated based on the number of times the drive pulse voltage is applied in the 14th step and the number of discharges detected in the 16th step while the drive pulse voltage is applied. 17th step to do and
Sensitivity parameters stored in the storage unit, discharge probabilities calculated in the fourth, eighth, thirteenth, and seventeenth steps, and the first, second, third, and fourth states. An eighteenth step of calculating the amount of light received by the optical sensor in the third and fourth states based on the pulse width of the drive pulse voltage, and
The sensitivity parameter stored in the storage unit, the discharge probability calculated in the thirteenth and seventeenth steps, the pulse width of the drive pulse voltage in the third and fourth states, and the ninth. When the pulse width of the drive pulse voltage is the reference pulse width and the light reception amount of the optical sensor is the reference light reception amount based on the discharge probability calculated in the step of 18 and the light reception amount calculated in the 18th step. A method for calculating the discharge probability of an optical detection system, which includes a nineteenth step of calculating the discharge probability of a normal discharge of the above.

Images