JPS5942667Y2 - light detection device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a photodetection device, and more specifically, the present invention relates to a photodetection device, and more specifically, it irradiates a photosensitive element with intermittent light related to the physical properties of a gas to be measured, and detects a change in the resistance value of the photosensitive element. The present invention relates to a photodetection device that obtains electrical signals.

FIG. 1 is an explanatory diagram of the configuration of a conventional photodetector. In the figure, 1 is a photosensitive element, such as a thermistor porometer,
2a and 2b are heating coils, 3a is a fixed resistor, 4 is a capacitor, 5 is a converter, 6 is a sector that makes continuous infrared light into intermittent light, 7 is a DC voltage applied to both ends of the photosensitive element 1, and 8 is a A power source for the coil, 9 a controller, 10 a linearizer, and 11 a computing unit.

The photosensitive element 1 and the fixed resistor 3a are connected in series, and their connection point C serves as a signal extraction point.
The linearizer 10 and the arithmetic unit 11 constitute a temperature control loop.

In the photodetector having the above configuration, a voltage signal determined by the resistance ratio between the photosensitive element 1 and the fixed resistor 3a is obtained from the connection point C.

The voltage signal is an AC signal in which an AC component is superimposed on a constant DC voltage, and the DC voltage is cut by a capacitor 4.
Thereafter, it is converted by the converter 5 into a desired output signal e corresponding only to the AC valve.

On the other hand, the voltage signal at the connection point C is also directly input to the arithmetic unit 11, which includes the arithmetic unit 11, the linearizer 10, and the controller 9.
, and is converted into a corresponding operation signal while passing through the coil power supply 8, and controls the current of the heating coils 2a and 2b to control the temperature of the thermostatic oven.

However, in the above conventional example, since the photosensitive element 1 has both a light detection function and a temperature detection function, the measurement current increases, and the photosensitive element 1 has a deterioration characteristic and is not stable for a long time as a detection element. It had the disadvantage of being lacking.

Furthermore, since the photosensitive element 1 is small in size, self-heating is likely to occur due to the measurement current, which increases the resistance of the photosensitive element 1, and as a result, there is a risk of causing the temperature of the thermostatic chamber to rise out of control. The present invention was developed in view of these drawbacks, and its purpose is to have a function to accurately control the temperature of a constant temperature bath containing a photosensitive element, and to generate electricity by changing the resistance value of the photosensitive element. The present invention provides a photodetection device for obtaining a signal.

The present invention provides a coil used in a thermostatic chamber containing a photosensitive element to function as both a heat source and a temperature detection end of the thermostatic chamber, and attaches the photosensitive element and the coil to the front and back surfaces of a substrate. It is characterized in that desired measurements are made by detecting light related to the physical properties of the gas to be measured while accurately controlling the temperature of the thermostatic chamber.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 2 is an explanatory diagram of the configuration of an embodiment of the present invention, and in the figure,
3b and 3c are fixed resistors, 12 is a substrate, and 13 is a coil, for example, a platinum thin film heater.

Further, other symbols in FIG. 2 that are the same as those in FIG. 1 have the same meanings and will not be described here.

FIG. 3 is an explanatory diagram of the structure of the peripheral part of the photosensitive element in the embodiment of the present invention, in which 21a and 21b are the substrates;
22 is a coil, 23 is a photosensitive element, 24a and 24b
is a spacer, and 25a and 25b are reflective films.

Note that the peripheral area of the photosensitive element is not limited to the one embodiment described above, and various modifications can be made within the scope of the structure in which the photosensitive element and the coil are attached to the substrate.

In addition, in FIG. 2, the coil 13 and the fixed resistor 3c are connected in series, and the coil 13, the coil power source 8, the controller 9,
The linearizer 10 and the arithmetic unit 11 constitute a temperature control loop.

In the photodetector having the above configuration, a voltage signal determined by the resistance of the coil 13 is sent to the calculator 11 from the connection point between the coil 13 and the fixed resistor 3c, and the coil 1
The current flowing through the resistor 3c is detected as a voltage drop across the fixed resistor 3c and sent to the arithmetic unit 11.

Based on these inputs, the arithmetic unit 11 performs calculations and outputs them to the linearizer 10, which linearizes them and outputs them as temperature values to the controller 9.

The signal is compared with a value set in advance by the controller 9, and a new output is sent to the coil power source 8 to control the output from the power source 8, which in turn controls the current of the coil 13, thereby controlling the constant temperature bath. temperature control.

On the other hand, a voltage signal determined by the resistance ratio between the photosensitive element 1 and the fixed resistor 3b is sent from the connection point C, the DC voltage is cut off by the capacitor 4, and the desired output signal corresponding to the AC component is output by the converter 5. converted to e.

According to the embodiment of the present invention as described in detail above,
The coil, which is the heat source of the thermostatic oven, also has a temperature detection function, and the photosensitive element functions only for light detection. This has the advantage of avoiding resistance drift and deterioration phenomena.

Furthermore, since the distance between the photosensitive element 1 and the coil 13 is shorter than in the conventional example, the thermostatic chamber containing them can be easily downsized, and the heat consumption of the thermostatic chamber can also be reduced compared to the conventional example.

Furthermore, when a platinum thin film heater is used as the coil 13, the nonlinearity of temperature-resistance characteristics is less than that of the photosensitive element, so the photosensitive element can also function as a temperature detection terminal. Compared to the conventional example, linearization is easy and control accuracy in the temperature control loop can be improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a conventional photodetection device, and FIG.
FIG. 3 is an explanatory diagram of the structure of an embodiment of the present invention. FIG. 1 and 23...photosensitive element, 3a, 3b
, and 3c...Fixed resistance, 2a, 2b, 1
3. 22... Coil, 4... Capacitor, 5... Converter, 6... Sector, 8... Power supply for coil , 9... Controller, 10... Linearizer, 11...
Arithmetic unit, 12, 21a, and 21b... board.

Claims (1)

[Scope of utility model registration request] In a photodetection device that irradiates a photosensitive element with intermittent light related to the physical properties of a gas to be measured and obtains an electrical signal based on a change in resistance of the photosensitive element, the photosensitive element generates an electrical signal based on a change in resistance. a coil that is used in a thermostatic chamber containing the photosensitive element and has the functions of both a heat source and a temperature detection end; and a substrate having the photosensitive element and the coil attached to the front and back surfaces, respectively. A photodetection device characterized by: