JPS6017714Y2 - Temperature control device for photoelectric conversion elements - Google Patents

Description

[Detailed description of the invention] The present invention improves the operation of photoelectric conversion elements employed in optical instruments such as smoke detectors or oil detectors used in environments where ambient temperature is not controlled or is insufficient. The present invention relates to a temperature control device for stabilization.

As an application example in which all-photoelectric conversion elements are used to measure oil concentration, FIG. 1 shows an example of the configuration of an oil concentration meter.

In FIG. 1, light from a light source 1 reaches a detection cell 2, and a continuous or patchy oily water is guided into a conduit 6, through which the light passes and enters a photoelectric conversion element 3.

The converted electrical signal is amplified by an amplifier 4 and sent to an indicator 5.

Therefore, the stable and high-performance conversion ability of the photoelectric conversion element 3 greatly influences the reliability of this oil concentration meter.

In general, photoelectric conversion elements have strong temperature dependence, and even though the incident light does not change, the electrical signal output changes significantly due to changes in ambient temperature.

Therefore, there was a drawback that the stability and reproducibility as an optical instrument could not be maintained, resulting in a significant loss of reliability.

Temperature chambers are used to eliminate these drawbacks, but if the measurement results of optical instruments are directly connected to fire or seawater contamination and no respite is possible, the stable operation of the temperature chamber becomes even more important. Therefore, a self-inspection function is required.

The present invention encapsulates a photoelectric conversion element in a constant temperature chamber, making it possible to control the temperature inside the chamber uniformly and within a specified temperature range, and outputting an alarm signal when an abnormality is detected in the temperature inside the chamber. It is an object of the present invention to provide an economical temperature control device for a photoelectric conversion element.

A detailed explanation will be given below based on the drawings.

FIG. 2a is a side cross-sectional view of an embodiment of the thermostatic oven according to the present invention, and FIG. 2 is a plan view illustrating an embodiment of the thermostatic oven according to the invention.

In FIG. 2a, an entrance window 11 made of a transparent material that transmits incident light is located inside the front lid 18, and creates an airtight space between the heating elements 17 via a gasket 12.

A photoelectric conversion element 13 made of, for example, cadmium sulfide, which receives incident light and generates an electric signal, is held in this airtight space with its back surface fixed to the head of a heating element 17 made of a metal member.

Inside the heating element 17, there is a heater 14 that heats itself, and a temperature detector 15 that measures the temperature of the heating element 17, such as a thermistor. They are arranged at equal positions with respect to the vertical central axis of the element 13 and sealed to the heating element 17 with resin or the like.

For example, the heaters 14A, 14B, and 14C are arranged at equal positions of 120 degrees with respect to the center as shown in FIG. They are evenly spaced.

Again in FIG. 2a, a part of the side surface of the heating element 17 is supported by a side body 19 made of an insulating material having a heat-insulating effect, and a terminal plate 20 made of an insulating material is similarly supported by the side body 19 while holding down the bottom of the heating element 17. The front cover 18 tightened to the entrance window 1
1. Press the heating element 17 through the gasket 12 and attach the front lid 1.
8, it is tightened to the side body 19.

Two conductive wires 16A and 16B from the photoelectric conversion element 13 are output terminals for electrical signals and penetrate through the heating element 17, but the output terminal portions are sealed with resin or the like to maintain airtightness.

Two conductive wires each from these terminals, the heater 14 and the temperature detector 15 are led to terminals on the multi-terminal board 20.

The above is the configuration of the constant temperature bath 27.

Next, FIG. 3 is an explanatory diagram showing an example of a temperature control device for a photoelectric conversion element according to the present invention.

In FIG. 3, the heaters 14A, 14B, and 14C maintain equal angular positions inside the heating element 17 with the photoelectric conversion element 13 as the center, and the temperature detectors 15A, 15B, and 15
The detected temperatures from these temperature detectors are sent as electrical signals to the temperature controller 25 connected by a multi-core cable from the thermostat 27, and the heating current for adjustment is passed through the multi-core cable to the heater. 14.

Furthermore, the detection signal from the temperature detector 15 is transmitted from the temperature controller 25 to a self-inspection device 26 disposed adjacent thereto, and if an abnormality is detected in the detection signal, an alarm signal is output.

The temperature controller 25 adjusts the temperature according to the signals from the respective temperature detectors when the ambient temperature cannot be maintained uniformly and stably due to the external environment, such as when there is sunlight, strong wind, or when the temperature is close to a heat-generating object. A plurality of temperature regulators are required so that the heaters can be individually controlled.

As for the control method, if the thermostatic chamber has sufficient heat retention and the heat capacity of the heating element is sufficient, a simple on/off control is sufficient because a large time constant for thermal changes can be achieved.

However, if an offset inevitably remains, PI
Control is also required.

In the self-inspection device 26, a plurality of comparators such as window comparators using arithmetic amplifiers are provided,
A detection signal from the respective temperature detector is connected to one input terminal of each comparator, and a signal indicating the reference temperature is connected to the other input terminal.

The abnormal output signal from the comparator is suppressed from being output as an alarm signal by a timer for a certain waiting period, that is, from when the constant temperature oven is started until the temperature reaches a specified temperature range.

Once the constant temperature oven reaches the specified temperature range, the detection signal of the temperature sensor deviates from the specified output range due to a disconnection or short circuit in one of the heaters, or the performance of the temperature sensor deteriorates. When the temperature distribution of the heating element in the thermostatic chamber becomes uneven and deviates from the specified temperature range, an alarm signal is output and an alarm circuit is activated to issue an alarm.

Next, the operation of the temperature control device for a photoelectric conversion element according to the present invention will be explained.

As for the control temperature, it is economical to set it at around 50° C., which is slightly higher than the normal temperature, without damaging the characteristics of the photoelectric conversion element.

If this temperature is maintained at a constant temperature around 20° C., it is necessary to control both heating and cooling due to changes in the outside air, which increases costs.

This is because when the set temperature is set to 50° C. which is higher than room temperature, heating control alone is sufficient.

Further, the control temperature range is defined by a desired meter, and is set to around 50°C±25°C, for example.

Furthermore, in order to improve control performance, the temperature distribution within the thermostatic chamber should be uniform and temperature changes should be made slowly.

For this reason, due to design considerations, the heating element 17 in Fig. 2a is
is made of a metal member in the shape of a circular mound to have as large a heat capacity as possible, and the photoelectric conversion element 13 is placed in an airtight space by the entrance window and packing 12 made of a transparent material.
The temperature detector 15 is sealed to the heating element 17 with resin or the like.

FIG. 4 is an explanatory diagram showing an example of temperature control of the device according to the present invention.

In FIG. 4, the vertical axis shows the temperature of the thermostatic chamber, and the horizontal axis shows time.

Before operating the constant temperature bath, the temperature indicates an air temperature of 20°C.

When the thermostat is turned on, the temperature is lower than the set temperature of 50°C, so the heaters 14A, 14B, and 14C in Fig. 3 are heated and the temperature starts to rise from 1 point, and eventually the waiting time (1
When the difference between point and point m) has passed, the set temperature at point m is 50'C!
When the heater 14 is turned off, the temperature begins to drop.

Thereafter, the heaters 14A, 14B, and 14C are repeatedly turned on and off depending on the temperatures detected by the temperature detectors 15A, 15B, and 15C, respectively.

As a result, the temperature remains within the specified control temperature range of 50°C ± 2.5°C.

Similarly, even when there is a change in temperature, the temperature inside the thermostatic chamber does not change suddenly but changes slowly, so the temperature has almost no effect on the photoelectric conversion element 13, and the reproducibility of the optical instrument is significantly improved. be done.

Note that when the optical instrument is used in an environment where the ambient temperature is relatively stable and the temperature distribution is uniform, the second
In FIG. If the regulator 25 is used for control, the economy will be significantly improved.

Further, even when a plurality of temperature detectors 15 are provided, electric signals corresponding to the detected temperatures from the temperature detectors 15A, 15B, and 15C are integrated or averaged, and the heater 14
A, 14B, and 14C all at the same time with a single temperature controller 2
Even if it is controlled by 5, the economical efficiency will be improved.

As explained above, the present invention is an optical instrument in which a photoelectric conversion element is sealed in a constant temperature bath, and the temperature inside the bath can be controlled uniformly and within a specified temperature range, so that abnormalities in the temperature inside the bath can be controlled. It is possible to provide an economical and high-performance temperature control device for a photoelectric conversion element that can output an alarm signal when it is recognized.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an oil concentration meter as an application example of the present invention, Fig. 2a is a side cross-sectional view of an embodiment of a constant temperature bath according to the present invention, and Fig. 2 is a diagram showing the configuration of an oil concentration meter according to the present invention. FIG. 3 is an explanatory diagram showing an example of a temperature control device for a photoelectric conversion element according to the present invention; FIG. 4 is an explanatory diagram showing an example of temperature control of the device according to the present invention. It is. 1...Light source, 2...Detection cell, 3...
...Photoelectric conversion element, 4...Amplifier, 5...
...Indicator, 6...Conduit, 11...
・Entrance window, 12...Patzkin, 13...
・Photoelectric conversion element, 14... Heater, 15...
...Temperature detector, 16...Conductor wire, 17...
...Heating element, 18...Front lid, 19...
・Side body, 20...Terminal board, 25...Temperature controller, 26...Self-inspection device, 27...
・Thermostatic bath.

Claims (2)

[Scope of utility model registration request] (1) In an optical instrument using a photoelectric conversion element, a plurality of heaters are arranged at equal positions with respect to the central axis of the photoelectric conversion element, and a plurality of temperature detectors corresponding to each heater are provided in proximity to the heaters. is made of a metal member with a large heat capacity and is sealed inside, and is symmetrical with respect to the central axis, and has a built-in heating element with the photoelectric conversion element fixed to the front surface on the central axis, and a side surface of the heating element. The top and bottom parts were sealed with a side body made of an insulating material with a heat-insulating effect and a terminal plate, and the front part was sealed with a front cover via a backing and a transparent material that transmitted light incident on the photoelectric conversion element. a constant temperature bath, a plurality of temperature regulators capable of controlling the temperature of the heating element by controlling the heating current to the corresponding heater according to the detection signal from the temperature detector, and the detection from the temperature regulator. A temperature control device for a photoelectric conversion element comprising a self-inspection device that inputs a signal and outputs an alarm signal when an abnormality is detected in the detection signal. (2) A plurality of heaters are enclosed in the heating element at equal positions with respect to the central axis, and one temperature detector is enclosed on the central axis near the photoelectric conversion element. Temperature control of a photoelectric conversion element according to claim 1 of the utility model registration claim, which comprises a constant temperature bath and one temperature regulator capable of controlling heating current to the heater according to a detection signal from the temperature detector. Device.