JP2000213990A - Temperature detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably and accurately switch light-introduction and light-shielding, to enhance temperature detection accuracy and to reduce a noise generated at the time of switching the light-introduction and the light shielding in a temperature detection device for detecting the temperature of an object to be detected by a non-contact, particularly in a shielding plate for controlling the light- introduction and the light-shielding of an infrared. SOLUTION: In the temperature detection device, the rotation direction of a DC motor 2 is alternately reversed and a light-shielding plate 1 driven by the DC motor 2 is collided to a stopper 13 to switch light-introduction and light-shielding of an infrared passage arriving at the infrared detector 3. After a power is fed to the DC motor 2 by an initial power feeding means to drive the light-shielding plate, the power is reduced and fed by a reduction power feeding means and the light-shielding plate 1 is collided to the stopper 13 and is stopped. Therefore, the light-introduction and light-shielding states of the infrared are stably and calmly switched and temperature detection accuracy can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature detecting device for detecting the temperature of an object in a non-contact manner, and more particularly, to a light shielding plate for controlling the incidence and shielding of infrared rays.

[0002]

2. Description of the Related Art Conventionally, in a device using a pyroelectric infrared detector as a temperature detecting device for detecting the temperature of an object in a non-contact manner, a light-shielding plate for switching between incident light of an infrared ray incident on the infrared detector and light shielding. Is provided. This light-shielding plate is made of a material that does not transmit infrared light, such as a metal plate, and its end is attached to the rotating shaft of a DC motor or AC motor and driven to rotate, and repeatedly enters and blocks infrared light reaching the infrared detector. There is a method of intermittent. That is, FIG.
As shown at 0, the semi-circular arc-shaped light shielding plate 1 is attached to the rotating shaft of the DC or AC motor 2 and is driven to rotate in the direction of the arrow, whereby the infrared rays incident on the infrared detector 3 are interrupted.

There is also a method in which a pulse is applied at a predetermined cycle using a pulse motor as a rotary drive source, and infrared light is intermittently transmitted by repeating, for example, normal rotation and inversion at a predetermined angle. For example, an example of a temperature measuring device disclosed in Japanese Patent Application Laid-Open No. 7-280652 will be described with reference to FIG. Chopper (light shield plate)
1 is driven by a quartz timepiece movement 4 which is a driving source based on the same principle as a pulse motor so as to reciprocate, and intermittently intercepts infrared rays reaching the infrared detector 3. The quartz watch movement 4 includes a permanent magnet 5, a core 6 and a coil 7, and the end of the chopper 1 is attached to the permanent magnet 5. The coil 7 receives a pulse input at the first and second input terminals 8 and 9, and in response to the pulse input, the permanent magnet 5 rotates and the chopper 1 reciprocates as indicated by the arrow.

[0004]

However, when the light shielding plate is rotated by using a DC motor as a drive source, there is a problem that the temperature measurement accuracy is low due to variations in the light input time and the light shielding time. The rotation speed of a DC motor generally fluctuates due to fluctuations in the power supply voltage or the like. If the rotation speed fluctuates,
The light-shielding period changes, and the fluctuation in the period also causes the output of the infrared detector to fluctuate, preventing accurate temperature detection. In order to stabilize the rotation speed, a complicated control circuit for performing feedback control by providing a means for detecting the rotation speed of a photo interrupter and the like and a means for adjusting the power supply voltage is required.

When an AC motor is used as a driving source,
Under a relatively stable frequency such as a commercial power supply, the number of rotations is easier to stabilize than a DC motor, but there is a problem that an AC power supply such as a commercial power supply is required. In the case of using a battery power supply such as a portable radiation thermometer or a radiation thermometer, this is only a DC power supply, and a complicated circuit for producing an AC power supply with a stable frequency is required, and it is difficult to realize this. When a quartz watch movement or pulse motor is used as the drive source, the drive is based on digital signals from a microprocessor, etc. Light incident to
There is a problem that it is difficult to switch the light shielding accurately. In other words, these driving sources are stopped by the balance of the attractive force and the repulsive force by the magnetic force, and are driven by changing the polarity of the magnetic force. At the moment of the stop, the light shielding plate swings and balances the attractive force and the repulsive force. There is a characteristic that it is stopped.

FIG. 12 shows the behavior characteristics of the pulse motor, that is, the driving pulse and the rotation angle of the rotation shaft of the pulse motor. The horizontal axis is the elapsed time. The driving pulse has a constant period t,
Pulses of CW (clockwise) and CCW (counterclockwise) are output alternately at a duty of 50%. Then, the rotation angle of the rotary shaft of the pulse motor causes an overshoot at the time of reaching the stop position as shown in the figure, then causes an undershoot, and the amplitude is reduced and stabilized at the stop position.

Since pulse motors and quartz timepiece movements generally have the behavior characteristics shown in FIG. 12, when these are used as a driving source of a light-shielding plate to intermittently transmit infrared light, light is blocked from entering light, or light is blocked from entering light. At the moment of switching to light, a situation occurs in which light input and light shielding are switched at very short intervals, which makes the output of the infrared detector unstable,
There is a problem that accuracy of temperature detection is lacking. In order to avoid this problem, there is a method in which the shape of the light-shielding plate is sufficiently large with respect to Δθ which is the maximum position of the swing, but in this case, there is a problem that the temperature detecting device itself also becomes large. .

[0008]

According to the present invention, there is provided an infrared detector for detecting infrared rays emitted by an object to be measured, a light shielding plate for shielding infrared rays incident on the infrared detector, A DC motor for driving the light shielding plate, a stopper provided at a stop position of the light shielding plate, control means for controlling the DC motor, and a temperature for converting the temperature of the device under test based on the output of the infrared detector. It has a conversion means, the control means has a positive power supply means for rotating the DC motor in the light incident direction and a negative power supply means for rotating the DC motor in the light blocking direction, and alternately reverses the rotation direction of the DC motor. The positive power supply unit and the negative power supply unit each switch between inputting light and blocking light of an infrared light path reaching the infrared detector, wherein the initial power supply unit supplies power during an initial initial power supply period; And reducing the power after a feeding period has a reduced power supply unit supplies the initial power supply period was configured to set shorter than the time required for the light shielding plate reaches the stopper.

According to the present invention, the control means alternately reverses the direction of rotation of the DC motor by the positive power supply means and the negative power supply means, and the light-shielding plate driven by the DC motor enters the infrared light path to the infrared detector. The temperature conversion means converts the temperature of the device under test based on the output of the infrared detector. In the positive power supply means and the negative power supply means, the initial power supply means supplies power to the DC motor during the initial initial power supply period, and thereafter, the reduced power supply means reduces and supplies power. Here, the initial power supply period is set to be shorter than the time required for the light shielding plate to reach the stopper, so that the light shielding plate started to be driven by the initial power supply means is reduced. Since the noise can be reduced and made to collide with the stopper, the sound of collision between the light shielding plate and the stopper can be reduced, and the light shielding plate can be held at the stop position where the stopper is located by the reduced power supply means even after the collision. Therefore, even if the light shielding plate is made sufficiently small, it is possible to stably switch between the light incident state and the light shielding state, and it is possible to quietly perform small and highly accurate temperature detection.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A temperature detecting device according to a first aspect of the present invention includes an infrared detector for detecting infrared rays emitted from an object to be measured, a light shielding plate for shielding infrared rays incident on the infrared detector, A DC motor for driving the light shielding plate, a stopper provided at a stop position of the light shielding plate, control means for controlling the DC motor, and a temperature for converting the temperature of the device under test based on the output of the infrared detector. It has a conversion means, the control means has a positive power supply means for rotating the DC motor in the light incident direction and a negative power supply means for rotating the DC motor in the light blocking direction, and alternately reverses the rotation direction of the DC motor. The positive power supply unit and the negative power supply unit switch between incoming and outgoing light of an infrared light path reaching the infrared detector, and the positive power supply unit and the negative power supply unit each supply power during an initial initial power supply period. And reducing the power after a period of time has a reduced power supply unit supplies the initial power supply period are those wherein the light shielding plate is shorter than the time required to reach the stopper.

The control means alternately reverses the direction of rotation of the DC motor by means of the positive power supply means and the negative power supply means, and a light-shielding plate driven by the DC motor switches between inputting and shielding of the infrared light path to the infrared detector. The temperature conversion means converts the temperature of the device under test based on the output of the infrared detector.
In the positive power supply means and the negative power supply means, the initial power supply means supplies power to the DC motor during the initial initial power supply period, and thereafter, the reduced power supply means reduces and supplies power. Here, the initial power supply period is set to be shorter than the time required for the light shielding plate to reach the stopper, so that the light shielding plate started to be driven by the initial power supply means is reduced. Since the noise can be reduced and made to collide with the stopper, the sound of collision between the light shielding plate and the stopper can be reduced, and the light shielding plate can be held at the stop position where the stopper is located by the reduced power supply means even after the collision. Therefore, even if the light shielding plate is made sufficiently small, it is possible to stably switch between the light incident state and the light shielding state, and it is possible to quietly perform small and highly accurate temperature detection.

Further, the control means of the temperature detecting device according to the second aspect of the present invention includes a voltage detecting means for detecting a power supply voltage for driving the DC motor, and an initial power supply according to the power supply voltage detected by the voltage detecting means. And an initial power supply period changing means for changing the period.

The initial power supply period changing means is configured to change the initial power supply period in accordance with the power supply voltage detected by the voltage detection means for detecting the power supply voltage. Even if the speed of the light shielding plate is reduced due to a decrease in the power supplied by the means and the negative power supply unit, the light shielding plate collides with the stopper by changing the initial power supply period according to the power supply voltage. , Can be stably switched between the light incident state and the light shielding state, and a small and highly accurate temperature detection can be performed quietly.

Further, the means for changing the initial power supply period of the temperature detecting device according to the third aspect of the present invention has a first monotone decreasing function having a monotonous decreasing relationship between the power supply voltage and the initial power supply period. , The initial power supply period is changed according to the power supply voltage based on the first monotonically decreasing function.

The initial power supply period changing means changes the initial power supply period from the power supply voltage detected by the voltage detection means based on the first monotone decreasing function. Even if the speed of the light-shielding plate decreases due to a decrease in the power supplied by the negative power supply means, the initial power supply period can be lengthened according to the decrease in the power supply voltage. The stopper can collide with and be held by the stopper, and can stably switch between the state of entering light and the state of shielding light, so that small and highly accurate temperature detection can be performed quietly.

Further, the initial power supply period changing means of the temperature detection device according to claim 4 of the present invention has a first table having a monotonically decreasing relationship between the power supply voltage and the initial power supply period. The initial power supply period is changed according to the power supply voltage based on a first table.

The initial power supply period changing means refers to the first table having a monotonically decreasing relationship between the power supply voltage and the initial power supply period, and determines the initial power supply period from the power supply voltage detected by the voltage detection means. Since the period is determined, the power supply voltage decreases and the power supplied by the positive power supply means and the negative power supply means decreases. The initial power supply period can be lengthened, so that the light-shielding plate can collide with and be held by the stopper, and can stably switch between the light-entering and light-shielding states. Can be done. Since the first table is referred to, the initial power supply period can be determined quickly.

According to a fifth aspect of the present invention, the control means of the temperature detecting device includes a voltage detecting means for detecting a power supply voltage for driving the DC motor, and a reduced power supply according to the power supply voltage detected by the voltage detecting means. Means for changing the amount of power supplied by the means.

The reduced power changing means is configured to change the power supply amount by the reduced power supply means in accordance with the power supply voltage detected by the voltage detection means. Even if the speed of the light-shielding plate decreases due to a decrease in the power supplied by the power supply unit, the light-shielding plate can be used as a stopper by changing the amount of power supplied by the reduced power supply unit according to the power supply voltage. Collision and holding can be performed, the state of incoming light and the state of blocked light can be switched stably, and small and highly accurate temperature detection can be performed quietly.

Further, the reduced power supply means of the temperature detecting device according to claim 6 of the present invention is configured to supply power intermittently, and the reduced power change means is configured to supply power with respect to a time when the reduced power supply means stops supplying power. There is a time ratio changing unit for changing the time ratio of the supply time, and the time ratio changing unit changes the time ratio according to the power supply voltage to change the power supply amount by the reduced power supply unit.

The reduced power supply means is configured to supply power intermittently, and the time ratio changing unit controls the power with respect to the time when the reduced power supply means stops power supply in accordance with the power supply voltage detected by the voltage detection means. By changing the time ratio of the supply time, even if the power supply voltage is reduced and the power supplied by the positive power supply unit and the negative power supply unit is reduced, the speed of the light shielding plate is reduced, The amount of power supply by the reduced power supply means can be changed in accordance with the power supply voltage with a simple circuit configuration, and the light-shielding plate collides with and is held by the stopper to stably switch between the light incident state and the light-shielded state. The temperature detection can be performed quietly with small size and high accuracy.

Further, the time ratio changing unit of the temperature detecting device according to claim 7 of the present invention has a second monotonically decreasing function having a monotonically decreasing relationship between the power supply voltage and the time ratio, and The time ratio is changed according to the power supply voltage based on the monotonically decreasing function of

The time ratio changing section determines the time ratio from the power supply voltage detected by the voltage detection means based on the second monotone decreasing function, so that the power supply voltage decreases and the positive power supply means and the negative power supply means Even if the speed of the light-shielding plate is reduced due to a decrease in the power supplied by the power supply, the time ratio is increased in accordance with the decrease in the power supply voltage, and the power supply to the time when the reduced power supply stops the power supply is performed. Time can be increased, so that the light-shielding plate can collide with and be held against the stopper, stably switch between the incident state and the light-shielded state, and perform small, highly accurate temperature detection quietly. be able to.

Further, the time ratio changing section of the temperature detecting device according to claim 8 of the present invention has a second table having a monotonically decreasing relationship between the power supply voltage and the time ratio, wherein the second table has a monotonically decreasing relationship. And changing the time ratio in accordance with the power supply voltage.

The time ratio changing unit refers to the second table having a monotonically decreasing relationship between the power supply voltage and the time ratio, and determines the time ratio from the power supply voltage detected by the voltage detection means. As the power supply voltage decreases and the power supplied by the positive power supply means and the negative power supply means decreases,
Even when the speed of the light-shielding plate is reduced, the time ratio can be increased in accordance with the decrease in the power supply voltage, and the time during which the reduced power supply means supplies power relative to the time during which power supply is stopped can be increased. , Hit the light blocking plate against the stopper,
It is possible to stably switch between the state of entering light and the state of shielding light, and it is possible to quietly perform small and highly accurate temperature detection. Further, since the second table is referred to, the time ratio can be determined quickly.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, in which a temperature detector is applied to a radiation thermometer for measuring the temperature of the eardrum and its vicinity.

(Embodiment 1) FIG. 1 is a configuration diagram of a radiation thermometer provided with a temperature detecting device according to Embodiment 1 of the present invention, FIG. 2 is an enlarged view of a main part of a light shielding plate, and FIG. It is a timing chart explaining operation of a board.

In FIG. 1, reference numeral 10 denotes an object to be measured whose temperature is, for example, an eardrum. Reference numeral 11 denotes a probe to be inserted into the ear canal, the diameter of which is reduced toward the tip so as to be easily inserted into the ear canal. Reference numeral 12 denotes a condensing means for condensing infrared light emitted from the eardrum 10, and the condensed infrared light enters the infrared detector 3 via the light shielding plate 1.

The light shielding plate 1 is controlled by a DC motor 2
3 while being reciprocatingly rotated while colliding with it, and the switching of the state of the incoming and outgoing of the infrared light reaching the infrared detector 3 is repeated intermittently. The infrared detector 3 is of a pyroelectric type, and its output changes in correlation with the differential value of the amount of infrared light to be detected. Here, the light shielding plate 1 is made of metal, and when the light is shielded, infrared rays emitted by the infrared detector 3 itself are reflected on the metal surface and enter the infrared detector 3.

That is, the output of the infrared detector 3 has a correlation with the temperature difference between the eardrum 10 and the infrared detector 3 due to the intermittent operation of the light shielding plate 1. A temperature sensor 14 for detecting the temperature of the infrared detector 3 is provided near the infrared detector 3. The temperature sensor 14 is based on a generally known thermistor.

The output of the infrared detector 3 is amplified by the amplifier 15, and the output voltage amplified by the amplifier 15 and the output voltage of the temperature sensor 14 are digitized by the AD converter 16. Reference numeral 17 denotes temperature conversion means for converting the temperature of the eardrum 10 based on the output of the AD converter 16. The output of the infrared detector 3 becomes an AC waveform due to the intermittent operation of the light shielding plate 1, and its amplitude is proportional to the difference between the temperature of the eardrum 10 and the fourth power of the temperature of the infrared detector 3. The temperature conversion means 17 converts the temperature of the eardrum 10 based on this relationship and displays it on the display means 18.

Reference numeral 19 denotes a control unit for controlling the driving of the DC motor 2, and comprises a positive power supply unit 20 for switching from a light blocking state to a light receiving state and a negative power supply unit 21 for switching from a light receiving state to a light blocking state. Further, the positive power supply means 20
Is composed of initial power supply means 20a for supplying electric power for driving the light shielding plate 1, and reduced power supply means 20b for supplying electric power to the light shielding plate 1 for holding the position of the stopper 13. And a reduced power supply 21b for supplying power for holding the position of the stopper 13 by the light shielding plate 1.

In FIG. 2, reference numeral 1 denotes a light-shielding plate, which is indicated by a solid line when stopped in a light-shielding state in which the infrared detector 3 is shielded from light, and is indicated by a broken line when stopped in a light-entering state.
The stopper 13 includes a light incident stop portion 13a that contacts when stopping in the light incident state, and a light shielding stop portion 13b that contacts when the light shielding plate 1 stops in the light shielding state, and when the DC motor 2 repeats normal rotation and reversal. The light shielding plate 1 collides with the light stop portion 13a and the light stop portion 13b of the stopper 13 and stops, so that the switching between the light input state and the light shielding state can be stably performed.

FIG. 3 shows a specific operation of the control means 19.
The voltage applied to the DC motor 2 and the rotation angle of the DC motor 2 are shown. The period t1 in FIG. 3 is a positive power supply period in which the light shielding plate 1 is driven into the light incident state and stopped in the light incident state. Light shield plate 1 during t2
Is driven by the negative power supply means 21 during a negative power supply period in which the light is driven in the light-shielded state and stopped in the light-shielded state. In this embodiment, t1 and t2 are set to the same time, but may be set to different times.

In the positive power supply period t1, t1a is an initial power supply period, in which the power P1 is supplied by the initial power supply means 20a to drive the light-shielding plate 1 to the light incident state, and t1b
Is a reduced power supply period, in which the reduced power supply means 20b supplies a power P2 smaller than P1 in order to hold the light blocking plate 1 at the position of the light stop portion 13a of the stopper 13.

Further, t1c is a time from when the light shielding plate 1 stopped in the light shielding state starts to move and collides with the light receiving stop portion 13a. Similarly, in the negative power supply period t2, t2a is an initial power supply period, and the power P1 is supplied by the initial power supply means 21a to drive the light shielding plate 1 in the light shielding state,
t2b is a reduced power supply period, in which the light shielding plate 1 is
Reduced power supply means 21 to keep it in the position 3b
The power P2 smaller than P1 is supplied by b. Also, t
2c is a time from when the light shielding plate 1 stopped in the light incident state starts to move and collides with the light shielding stop portion 13b of the stopper 13.

Here, the initial power supply period t1a is t1c.
The initial power supply period t2a is set shorter than t2c. That is, the light shielding plate 1 is connected to the positive power supply unit 20.
The power supply (P1) by the initial power supply means 20a starts to move from the light blocking state to the light receiving state, and then the power is reduced to P2 by the reduced power supply means 20b, so that the moving speed of the light shielding plate 1 is reduced. From the light incident stop portion 13a of the stopper 13 to be held at the position of the light incident stop portion 13a, and then shielded from the light incident state by the power supply (P1) by the initial power supply means 21a of the negative power supply means 21. Then, the moving speed of the light shielding plate 1 is reduced by lowering the electric power to P2 by the reduced electric power supply means 21b, and then the light is collided with the light shielding stopping portion 13b of the stopper 13, so that the light shielding stopping portion 13b In position.

Therefore, the initial power supply periods t1a, t2a
Is set shorter than the time required for the light shielding plate 1 to collide with the stopper 13, the power is reduced before the collision with the stopper 13, and the speed of the light shielding plate 1 is reduced. The impact at the time of collision becomes small, and the swing angle Δθ at the time of stop can be made very small.
Further, the collision noise generated when the light shielding plate 1 collides with the stopper 13 can be reduced. Therefore, even if the light shielding plate is made sufficiently small, it is possible to stably switch between light input and light shielding, and to measure the body temperature quietly and accurately.

In this embodiment, the reduced power supply means 20
Although b and 21b are configured to constantly supply a smaller amount of power than the initial power supply units 20a and 21a, the present invention is not restricted to the present invention, and the same effect can be obtained even if the power is intermittently configured.

(Embodiment 2) FIG. 4 is a block diagram of a radiation thermometer provided with a temperature detecting device according to Embodiment 2 of the present invention, FIG. 5 is a diagram showing a first monotone decreasing function, and FIG. FIG. 4 is a timing chart illustrating the operation of the embodiment.

In FIG. 4, reference numeral 23 denotes a battery as a power supply for operating the radiation thermometer, which is a drive power supply for the DC motor 2. 24 is a voltage detecting means for detecting the voltage of the battery 23;
Reference numeral 25 denotes an initial power supply period changing unit that changes the initial power supply period according to the power supply voltage detected by the voltage detection unit 24. The initial power supply period changing means 25 has a first monotone decreasing function 26 having a monotonically decreasing relationship between the power supply voltage V and the initial power supply period T as shown in FIG. The other components are the same as in the first embodiment, and a description thereof will be omitted.

In the above configuration, the voltage detecting means 24 detects the voltage V of the power supply 23, and the initial power supply period changing means 2
5 calculates the initial power supply period T based on the first monotone decreasing function 26 and transmits the calculated initial power supply period to the initial power supply means 20a and 21a.

Next, the operation of the light shielding plate 1 will be specifically described with reference to FIG. FIG. 6 shows the voltage applied to the DC motor 2 and the rotation angle of the DC motor 2. The broken line indicates the case where the battery 23 is newly used and the voltage is high, and the solid line indicates the case where the battery 23 is used and the voltage is reduced. I have.

First, it is assumed that when the battery 23 is new and the power supply voltage is high, the power supply voltage V1 (for example, 3.5 V) is detected by the voltage detection means 24. The initial power supply period changing unit 25 calculates an initial power supply period T1 (for example, 5 msec) based on the first monotone decreasing function 26, and sends a signal to the initial power supply units 20a and 21a. Positive power supply means 20
The initial power supply means 20a supplies the power supply voltage V1 to the DC motor 2 during the initial power supply period T1, and drives the light blocking plate 1 from the light blocking state to the light receiving state. Then, the reduced power supply means 20b supplies a voltage V1a lower than the power supply voltage V1 to reduce the moving speed of the light shielding plate 1, and then stops the stopper 13
And is held at the position of the light incident stop portion 13a. Then, the initial power supply unit 21a of the negative power supply unit 21 supplies the power supply voltage V1 to the DC motor 2 during the initial power supply period T1, and drives the light shielding plate 1 from the light incident state to the light shielding state. The reduced power supply means 21b supplies a voltage V1a lower than the power supply voltage V1 to reduce the moving speed of the light shielding plate 1, and then stops the light shielding stop portion 13 of the stopper 13.
b, and is held at the position of the light shielding stop 13b.
By repeating light input and light shielding in this manner, the infrared light incident on the infrared detector 3 is intermittently intermittent.

On the other hand, consider the case where the voltage of the battery 23 drops. It is assumed that the power supply voltage V2 (for example, 2.0 V) is detected by the voltage detection unit 24. The initial power supply period changing means 25 calculates an initial power supply period T2 (for example, 10 msec) based on the first monotone decreasing function 26, and sends a signal to the initial power supply means 20a, 21a. Positive power supply means 2
The initial power supply means 20a of 0 supplies the power supply voltage V2 to the DC motor 2 during the initial power supply period T2, and drives the light blocking plate 1 from the light blocking state to the light receiving state. Then, the reduced power supply means 20b supplies a voltage V2a lower than the power supply voltage V2 to reduce the moving speed of the light shielding plate 1, and then the stopper 13
And is held at the position of the light incident stop portion 13a. Then, the initial power supply unit 21a of the negative power supply unit 21 supplies the power supply voltage V2 to the DC motor 2 during the initial power supply period T2, and drives the light shielding plate 1 from the light incident state to the light shielding state. The reduced power supply means 21b supplies a voltage V2a lower than the power supply voltage V2 to reduce the moving speed of the light shielding plate 1 and then stops the light shielding stop portion 13 of the stopper 13.
b, and is held at the position of the light shielding stop 13b.
By repeating light input and light shielding in this manner, the infrared light incident on the infrared detector 3 is intermittently intermittent.

Thus, the initial power supply period changing means 25 changes the initial power supply period T according to the power supply voltage of the battery 23 detected by the voltage detection means 24.

Here, even if the voltage supplied by the positive power supply means 20 and the negative power supply means 21 decreases due to the decrease in the power supply voltage of the battery 23, the initial power supply period T
Is constant and does not change. In this case, the battery 23
When the voltage is high, the light-shielding plate 1 that has been driven accurately cannot be driven accurately due to a decrease in the voltage. That is, the moving speed of the light shielding plate 1 decreases with a decrease in the power supply voltage, and the initial power supply units 20a and 21a and the reduced power supply unit 20
b, 21b, the light shielding plate 1
The vehicle stops halfway without colliding with 3. In such a case, it is impossible to accurately switch between the light incident and the light shielding of the infrared detector 3, so that the output of the infrared detector is unstable and accurate temperature measurement cannot be performed.

Therefore, in this embodiment, the initial power supply period changing means 25 is configured to change the initial power supply period T longer according to the decrease in the voltage of the battery 23. That is,
The first monotone decreasing function 26 representing the relationship between the power supply voltage V and the initial power supply period T is obtained by the initial power supply means 20a, 21a and the reduced power supply means 20b, 21b even when the voltage of the battery 23 decreases. It may be determined in advance by an experiment so that the light shielding plate 1 can collide with the stopper 13 by supplying power.

Therefore, according to the present embodiment, the initial power supply period changing means 25 changes the initial power supply period T from the power supply voltage of the battery 23 detected by the voltage detection means 24 based on the first monotone decreasing function 26. Therefore, even if the speed of the light-shielding plate decreases due to a decrease in the power supply voltage and a decrease in the power supplied by the positive power supply unit and the negative power supply unit, the initial power is reduced according to the decrease in the power supply voltage. Since the supply period T can be lengthened, the light-shielding plate 1 can collide with and be held by the stopper 13, and can stably switch between the light incident state and the light-shielding state. Can be done.

In this embodiment, the initial power supply period changing means 25 has a first monotone decreasing function 26 having a monotonically decreasing relationship between the power supply voltage and the initial power supply period. Although the initial power supply period is changed according to the power supply voltage based on the function 26, the initial power supply period changing means 25 has a first table having a monotonically decreasing relationship between the power supply voltage and the initial power supply period. The same effect can be obtained even with a configuration having.

Since the initial power supply period is determined with reference to the first table, compared with the case where the initial power supply period is calculated based on the first monotone decreasing function 26,
The initial power supply period can be determined in a shorter time.

(Embodiment 3) FIG. 7 is a diagram showing a configuration of a radiation thermometer provided with a temperature detecting device according to Embodiment 3 of the present invention, FIG. 8 is a diagram showing a second monotone decreasing function, and FIG. FIG. 4 is a timing chart illustrating the operation of the embodiment.

In FIG. 7, reference numeral 27 denotes a voltage detecting means 24.
Power supply means 2 according to the voltage of battery 23 detected by
This is a reduced power changing unit that changes the power supply amount according to 0b and 21b. In this embodiment, the reduced power supply means 20
b, 21b are configured to intermittently supply power, and the reduced power changing unit 27 is a time ratio changing unit that changes the time ratio of the time during which power is supplied to the time during which the reduced power supplying units 20b, 21b stop supplying power. 28.
The time ratio changing unit 28 has a second monotone decreasing function 29 having a monotonically decreasing relationship between the voltage V of the battery 23 as a power supply and the time ratio A, as shown in FIG. The other components are the same as those in the above-described embodiment, and the description is omitted.

In the above configuration, the voltage detecting means 24 detects the voltage V of the power supply 23 and transmits it to the reduced power changing means 27. Then, the time ratio changing unit 28 calculates the time ratio A from the voltage V based on the second monotone decreasing function 29, and transmits the calculated time ratio A to the reduced power supply units 20b and 21b.

Next, the operation of the light shielding plate 1 will be specifically described with reference to FIG. FIG. 9 shows the voltage applied to the DC motor 2 and the rotation angle of the DC motor 2. The dotted line shows the case where the battery 23 is newly used and the voltage is high, and the solid line shows the case where the battery 23 is used and the voltage is reduced. I have.

First, when the battery 23 is new and the voltage detecting means 2
4, when the power supply voltage is high and detected as V1 (for example, 3.5 V), the time ratio changing unit 28 calculates the time ratio A1 from the power supply voltage V1 based on the second monotone decreasing function 29, and A signal is sent to the supply means 20b, 21b. The initial power supply means 20a of the positive power supply means 20 supplies the power supply voltage V1 to the DC motor 2 during the initial power supply period T (constant regardless of the power supply voltage), and changes the light shielding plate 1 from the light shielding state to the light receiving state. And drive. Then, the reduced power supply means 20b intermittently supplies the power supply voltage V1. In FIG. 9, T1off is the time during which power supply is stopped,
1on is a time during which the power supply voltage V1 is supplied. Here, the reduced power supply means 20b intermittently supplies power so that the power supply voltage V1 is supplied to the power supply stopped time, that is, T1on / T1off becomes equal to the time ratio A1. ing. The light-shielding plate 1 is intermittently supplied with power by the reduced power supply unit 20b, so that the moving speed is reduced, and the light-shielding plate 1 collides with the light stop portion 13a of the stopper 13 and is held at the position of the light stop portion 13a. You. Next, the initial power supply means 21 of the negative power supply means 21
“a” supplies the power supply voltage V1 to the DC motor 2 during the initial power supply period T (constant irrespective of the power supply voltage), and drives the light shielding plate 1 from the light incident state to the light shielding state. Then, the reduced power supply means 21b intermittently supplies power so that T1on / T1off = A1, and the light shielding plate 1 collides with the light shielding stop portion 13b of the stopper 13 in a state where the moving speed is reduced,
It is held at the position of the light blocking part 13b. In this manner, light input and light shielding are repeated, and the infrared light incident on the infrared detector 3 is intermittent.

On the other hand, when the voltage of the battery 23 decreases and the power supply voltage V 2 (for example, 2.0 V) is detected by the voltage detection unit 24, the time ratio changing unit 28 performs the operation based on the second monotone decreasing function 29. The time ratio A2 is calculated from the power supply voltage V2, and a signal is sent to the reduced power supply units 20b and 21b. The initial power supply means 20a of the positive power supply means 20 supplies the power supply voltage V2 to the DC motor 2 during the initial power supply period T (constant irrespective of the power supply voltage), and changes the light shielding plate 1 from the light shielding state to the light receiving state. And drive. And reduced power supply means 2
0b is intermittently supplied with power so that T2on / T2off = A2, and the light-shielding plate 1 collides with the light-incident stop portion 13a of the stopper 13 in a state where the moving speed is reduced, and the light-incident stop portion 13a Held in position. Next, the negative power supply means 21
During the initial power supply period T (constant irrespective of the power supply voltage), the initial power supply means 21a supplies the power supply voltage V2 to the DC motor 2
To drive the light shielding plate 1 from the light incident state to the light shielding state.

Then, the reduced power supply means 21b is switched to T2on
Power is intermittently supplied so that / T2off = A2,
The light shielding plate 1 collides with the light shielding stop portion 13b of the stopper 13 in a state where the moving speed is reduced, and is held at the position of the light shielding stop portion 13b. In this manner, light input and light shielding are repeated, and the infrared light incident on the infrared detector 3 is intermittent.

Here, the time ratio A2 when the power supply voltage V decreases from V1 to V2 is such that even if the voltage of the battery 23 decreases, the light shielding plate 1 is moved to the stopper 13 by the power supply by the reduced power supply means 20b and 21b. What is necessary is just to set it so that it may collide reliably and be held. That is, if the time ratio is set large when the power supply voltage drops, the reduced power supply means 20
b, the ratio of the power supply time to the power supply stop time to the power supply stop time can be increased,
The light shielding plate 1 can reliably collide with the stopper 13 and be held.

Accordingly, the time ratio changing unit 28 calculates the time ratio from the voltage of the battery 23 detected by the voltage detecting means 24 based on the second monotonically decreasing function 29. Even if the speed of the light-shielding plate decreases due to a decrease in the power supplied by the supply unit and the negative power supply unit, the time ratio is increased according to the decrease in the power supply voltage, and the reduced power supply units 20b and 21b Can increase the power supply time relative to the power supply stop time, so that the light shielding plate 1 collides with the stopper 13,
It is possible to stably switch between the state of entering light and the state of shielding light, and it is possible to quietly perform small and highly accurate temperature detection.

In the present embodiment, the time ratio changing section 28 has the second monotonous decreasing relationship between the power supply voltage and the time ratio.
And the time ratio is changed according to the power supply voltage based on the second monotone decreasing function 29. However, the time ratio changing unit 28 monotonically decreases between the power supply voltage and the time ratio. The same effect can be obtained by a configuration having a second table having the relationship Then, since the time ratio is determined with reference to the second table, compared with the case where the time ratio is calculated based on the second monotone decreasing function 29,
The time ratio can be determined in a shorter time.

In this embodiment, the reduced power supply means 20
b and 21b supply power intermittently and change the ratio of the time for supplying power to the time for stopping power supply in accordance with the power supply voltage. The power supply units 20b and 21b are configured to supply a constant power smaller than the power supplied by the initial power supply units 20a and 21a, and the power values supplied by the reduced power supply units 20b and 21b are changed according to the power supply voltage. Has the same effect.

Although the embodiment has been described as an application example in which the temperature detecting device of the present invention is mounted on a portable thermometer for measuring the temperature of the eardrum in a non-contact manner, this is intended to limit the present invention. For example, the present invention may be applied to a microwave oven, an air conditioner, or the like which is incorporated in a device and detects and controls the temperature in a non-contact manner.

[0064]

As described above, the heating device of the present invention has the following effects.

(1) The control means alternately reverses the direction of rotation of the DC motor by means of the positive power supply means and the negative power supply means, and a light-shielding plate driven by the DC motor controls light entering and blocking of the infrared light path to the infrared detector. The switching and temperature conversion means converts the temperature of the device under test based on the output of the infrared detector. In the positive power supply means and the negative power supply means, the initial power supply means supplies power to the DC motor during the initial initial power supply period, and thereafter, the reduced power supply means reduces and supplies power. Since the initial power supply period is set shorter than the time required for the light shielding plate to reach the stopper, the light shielding plate started to be driven by the initial power supply means is reduced. After that, the collision with the stopper can be performed, and the sound of collision between the light shielding plate and the stopper can be reduced. Also, the swing of the light shielding plate at the time of collision can be reduced, and the light shielding plate can be held at the stop position where the stopper is provided by the reduced power supply means even after the collision. And the state of light shielding can be stably switched, and small and highly accurate temperature detection can be performed quietly.

(2) The initial power supply period changing means is configured to change the initial power supply period in accordance with the power supply voltage detected by the voltage detection means for detecting the power supply voltage. Even if the speed of the light-shielding plate is reduced due to a decrease in the power supplied by the supply unit and the negative power supply unit, the initial power supply period is changed according to the power supply voltage so that the light-shielding plate can be used as a stopper. Collision and holding can be performed, the state of incoming light and the state of blocked light can be switched stably, and small and highly accurate temperature detection can be performed quietly.

(3) The initial power supply period changing means changes the initial power supply period from the power supply voltage detected by the voltage detection means based on the first monotone decreasing function. Even if the speed of the light-shielding plate decreases due to a decrease in the power supplied by the means and the negative power supply unit, the initial power supply period can be lengthened in accordance with the decrease in the power supply voltage. Can be caused to collide with and be held by the stopper, and the state of incoming light and the state of blocked light can be stably switched, so that small and highly accurate temperature detection can be performed quietly.

(4) The initial power supply period changing means refers to the first table having a monotonically decreasing relationship between the power supply voltage and the initial power supply period, and calculates the initial power from the power supply voltage detected by the voltage detection means. Since the supply period is determined, the power supply voltage decreases, and the power supplied by the positive power supply means and the negative power supply means decreases. Accordingly, the initial power supply period can be lengthened, so that the light-shielding plate can collide with the stopper and be held, and can stably switch between the light-in and light-out states. Can be done quietly. Since the first table is referred to, the initial power supply period can be determined quickly.

(5) The reduced power changing means is configured to change the amount of power supplied by the reduced power supply means in accordance with the power supply voltage detected by the voltage detecting means. Even if the speed of the light-shielding plate is reduced due to a decrease in the power supplied by the negative power supply unit, the light-shielding plate is stopped by changing the power supply amount by the reduced power supply unit according to the power supply voltage. Can be stably switched between the light incident state and the light shielding state, and small and highly accurate temperature detection can be performed quietly.

(6) The reduced power supply means is configured to supply power intermittently, and the time ratio changing unit controls the time during which the reduced power supply means stops power supply according to the power supply voltage detected by the voltage detection means. Even if the speed of the light blocking plate is reduced by changing the time ratio of the power supply time, the power supply voltage is reduced and the power supplied by the positive power supply unit and the negative power supply unit is reduced. It is possible to change the amount of power supply by the reduced power supply means in accordance with the power supply voltage with a simple circuit configuration, and to strike and hold the light shielding plate against the stopper to stably maintain the state of light input and light shielding. Switching can be performed, and small and highly accurate temperature detection can be performed quietly.

(7) Since the time ratio changing section determines the time ratio from the power supply voltage detected by the voltage detection means based on the second monotonically decreasing function, the power supply voltage decreases and the positive power supply means and the negative power supply Even if the speed of the light-shielding plate is reduced due to a decrease in the power supplied by the means, the time ratio is increased in accordance with the decrease in the power supply voltage, and the power for the time when the reduced power supply stops the power supply is reduced. Since the supply time can be increased, the light-shielding plate can collide with and be held by the stopper, and the state of light input and light-shielding can be switched stably. It can be carried out.

(8) The time ratio changing unit refers to the second table having a monotonically decreasing relationship between the power supply voltage and the time ratio, and determines the time ratio from the power supply voltage detected by the voltage detection means. However, even when the speed of the light shielding plate is reduced due to a decrease in the power supply voltage and a decrease in the power supplied by the positive power supply unit and the negative power supply unit, the time ratio is increased according to the decrease in the power supply voltage. However, since the power supply time can be increased relative to the time at which the reduced power supply means stops the power supply, the light shielding plate can collide with the stopper and be held, and the state of light input and light shielding can be stabilized. Switching can be performed, and small and highly accurate temperature detection can be performed quietly. Further, since the second table is referred to, the time ratio can be determined quickly.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a radiation thermometer including a temperature detection device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of a light shielding plate of the temperature detecting device.

FIG. 3 is a timing chart for explaining the operation of the light shielding plate of the temperature detecting device.

FIG. 4 is a configuration diagram of a radiation thermometer including a temperature detection device according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a first monotone decreasing function of the temperature detection device.

FIG. 6 is a timing chart for explaining the operation of the light shielding plate of the temperature detecting device.

FIG. 7 is a configuration diagram of a radiation thermometer including a temperature detection device according to a third embodiment of the present invention.

FIG. 8 is a view showing a second monotone decreasing function of the temperature detection device.

FIG. 9 is a timing chart for explaining the operation of the light shielding plate of the temperature detecting device.

FIG. 10 is a configuration diagram of a conventional temperature detection device.

FIG. 11 is a configuration diagram of a conventional temperature detection device.

FIG. 12 is a timing chart illustrating the operation of the temperature detection device.

DESCRIPTION OF SYMBOLS 1 Shield plate 2 DC motor 3 Infrared detector 10 Device under test 13 Stopper 17 Temperature conversion means 19 Control means 20 Positive power supply means 21 Negative power supply means 20a, 21a Initial power supply means 20b, 21b Reduced power Supply means 23 Battery (power supply voltage) 24 Voltage detecting means 25 Initial power supply period changing means 26 First monotonous decreasing function 27 Decreasing power changing means 28 Time ratio changing unit 29 Second monotonic decreasing function

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuyuki Kanazawa 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Term (reference) 2G066 BA01 BA35 BB07 BB13 BC15 CA08

Claims (8)

[Claims] 1. An infrared detector for detecting infrared rays emitted from an object to be measured, a light shielding plate for shielding infrared light incident on the infrared detector, a DC motor for driving the light shielding plate, and a stop of the light shielding plate A stopper provided at a position, control means for controlling the DC motor, and temperature conversion means for converting the temperature of the device under test based on the output of the infrared detector, wherein the control means inputs the DC motor. It has positive power supply means for rotating in the light direction and negative power supply means for rotating in the light blocking direction, and alternately reverses the rotation direction of the DC motor to switch between incoming light and blocking of the infrared light path to the infrared detector. The positive power supply unit and the negative power supply unit each supply initial power during an initial power supply period; and a reduced power supply that reduces and supplies power after the initial power supply period. Has a step, the initial power supply period is the temperature detecting apparatus wherein the light shielding plate is set to be shorter than the time required to reach the stopper. 2. The control means includes: voltage detecting means for detecting a power supply voltage for driving the DC motor; and initial power supply period changing means for changing an initial power supply period in accordance with the power supply voltage detected by the voltage detecting means. The temperature detection device according to claim 1, further comprising: 3. An initial power supply period changing means has a first monotone decreasing function having a monotonically decreasing relationship between a power supply voltage and an initial power supply period, and based on the first monotonic decreasing function, 3. The temperature detecting device according to claim 2, wherein the initial power supply period is changed according to a voltage. 4. An initial power supply period changing means includes a first table having a monotonically decreasing relationship between a power supply voltage and an initial power supply period, and based on the first table, according to the power supply voltage. 3. The method according to claim 2, wherein the initial power supply period is changed.
The temperature detection device as described in the above. 5. The control means includes: voltage detection means for detecting a power supply voltage for driving the DC motor; and reduced power changing means for changing a power supply amount by the reduced power supply means in accordance with the power supply voltage detected by the voltage detection means. The temperature detecting device according to claim 1, comprising: 6. The reduced power supply means is configured to supply power intermittently, and the reduced power change means changes a time ratio of a power supply time to a power supply stop time of the reduced power supply means. 6. The temperature detecting device according to claim 5, further comprising a changing unit, wherein the time ratio changing unit changes a time ratio according to a power supply voltage to change a power supply amount by the reduced power supply unit. 7. The time ratio changing unit has a second monotone decreasing function having a monotonically decreasing relationship between the power supply voltage and the time ratio,
7. The temperature detecting device according to claim 6, wherein the time ratio is changed according to the power supply voltage based on the second monotone decreasing function. 8. The time ratio changing unit has a second table having a monotonically decreasing relationship between the power supply voltage and the time ratio, and based on the second table, changes the time ratio according to the power supply voltage. 7. The temperature detecting device according to claim 6, wherein the temperature is changed.