JP3537354B2 - Temperature control method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling a temperature of a controlled portion to be maintained at a constant reference temperature by cooling or heating the controlled portion by a Peltier element.

[0002]

2. Description of the Related Art A Peltier element has a heat absorbing surface and a heat radiating surface. When one surface heats a controlled part by a heat radiating effect, the other surface is cooled by a heat absorbing effect. Conversely, when one surface is cooling the controlled part by the heat absorption effect, the other surface is heated by the heat radiation effect. In the Peltier element, whether the surface for cooling / heating the controlled part has a heat radiation effect or a heat absorption effect is determined by the direction of the drive current applied to the Peltier element.

A conventional temperature control device using a Peltier element amplifies a current based on a temperature difference between a temperature of a controlled portion detected by a temperature detecting means and a preset reference temperature at a predetermined amplification factor. By applying this to the Peltier element as a drive current to heat or cool the controlled part,
The temperature of the controlled part was controlled to be constant.

[0004]

Incidentally, the temperature of the controlled portion is affected by its ambient temperature. Then, as the ambient temperature becomes farther from the reference temperature of the controlled portion, the influence becomes larger. However, in the conventional temperature control device, the Peltier element is only cooled or heated by the drive current based on the temperature difference between the temperature of the controlled part and the reference temperature without considering the change in the ambient temperature. For example, when the ambient temperature is extremely high, the output of the cooling operation is insufficient, and when the ambient temperature is extremely low, the output of the heating operation is insufficient, and the controlled portion cannot be maintained at the reference temperature. The problem arises.

In order to solve the above problem, it is conceivable to previously set a large amplification factor of a current for driving the Peltier element. However, in the conventional temperature control device, even when the ambient temperature and the temperature of the controlled portion are balanced and stable, the Peltier element is heated or cooled with the same output as in the other case. So
When the amplification factor is set to be large, when the ambient temperature and the temperature of the controlled part are balanced, the controlled part is excessively cooled or heated by the Peltier element, and the temperature of the controlled part passes the reference temperature. I will. Then, in order to return the temperature that the Peltier device has passed, the cooling operation and the heating operation are frequently repeated, which causes a problem that the Peltier device is significantly deteriorated.

The present invention has been made in view of the above circumstances, and it is possible to prevent deterioration of a Peltier element and stably maintain the temperature of a controlled portion at a reference temperature even when the ambient temperature changes. It is an object to provide a possible temperature control method and device.

[0007]

According to a first aspect of the present invention, there is provided a temperature control method in which a Peltier element performs one of a heating operation and a cooling operation so that a temperature of a controlled portion is set to a predetermined reference temperature. In the case where the control is performed so as to maintain the temperature and the cooling operation is performed by the Peltier element, the output of the cooling operation of the Peltier element is increased when the ambient temperature of the controlled part rises to a preset upper limit temperature or higher. When the heating operation is performed by the Peltier element, the output of the heating operation of the Peltier element is increased when the ambient temperature falls below the preset lower limit temperature.

According to a second aspect of the present invention, there is provided a temperature control device comprising: a Peltier element; control temperature detecting means for detecting a temperature of a controlled portion; and a temperature difference between a detection result of the control temperature detecting means and a preset reference temperature. Amplifying means for amplifying the current according to the above with a changeable amplification factor and supplying the current as a drive current to the Peltier element, and causing the Peltier element to perform one of heating and cooling operations, thereby controlling the temperature of the controlled portion. A temperature control device that controls the temperature of the controllable portion to be maintained at a reference temperature, and an amplification device that determines an amplification factor of the amplification device in response to a detection result of the ambient temperature detection device. Rate determining means, wherein the amplification factor determining means performs a cooling operation when the Peltier element performs a cooling operation and the ambient temperature becomes higher than a preset upper limit temperature, and performs a heating operation when the Peltier element performs a heating operation. When the temperature falls below the lower limit temperature set beforehand, having characterized in that increasing the amplification factor of the amplifying means.

[0009]

According to the first aspect of the present invention, when the ambient temperature increases while the Peltier element is performing a cooling operation, the temperature of the controlled portion is affected in a direction in which the temperature increases. However, in the present invention, when the ambient temperature is equal to or higher than the upper limit temperature, the output of the cooling operation of the Peltier device increases, so that the balance between the influence of the ambient temperature and the output of the Peltier device is maintained.
The temperature of the controlled part is stably maintained at the reference temperature. Further, when the ambient temperature is lower than the upper limit temperature, the output of the cooling operation of the Peltier element decreases, and excessive cooling of the controlled portion is prevented. On the other hand, if the Peltier element is performing a heating operation, the output of the Peltier element heating operation increases when the ambient temperature falls below the lower limit temperature. Is maintained, and the temperature of the controlled portion is stably maintained at the reference temperature. Further, when the ambient temperature is equal to or higher than the lower limit temperature, the output of the heating operation of the Peltier element decreases, and excessive heating of the controlled portion is prevented.

<Invention of Claim 2> When the ambient temperature rises while the Peltier element is performing the cooling operation, the temperature of the controlled portion is affected in a direction in which the temperature rises. However, when the ambient temperature becomes higher than the upper limit temperature, the amplification factor of the amplification device is increased by the amplification factor determination device, and the drive current to the Peltier element increases. As a result, the output of the cooling operation of the Peltier element increases, the balance between the influence of the ambient temperature and the output of the Peltier element is maintained, and the temperature of the controlled portion is stably maintained at the reference temperature. Further, when the ambient temperature is lower than the upper limit temperature, the output of the cooling operation of the Peltier element is reduced by lowering the amplification factor, and excessive cooling of the controlled part is prevented. On the other hand, when the heating operation is performed on the Peltier element, if the ambient temperature is lower than the lower limit temperature, the amplification factor of the amplification means is increased by the amplification factor determining means, so that the drive current to the Peltier element increases, The output of the heating operation of the Peltier element increases. As a result, the balance between the influence of the ambient temperature and the output of the Peltier element is maintained, and the temperature of the controlled portion is stably maintained at the reference temperature. Further, when the ambient temperature is lower than the lower limit temperature, the output of the heating operation of the Peltier element is reduced by lowering the amplification factor, and excessive heating of the controlled portion is prevented.

[0011]

According to the first and second aspects of the present invention, even if the ambient temperature changes, the output of the Peltier element is changed to be large or small so as to offset the change, so that the temperature of the controlled portion can be stabilized. To maintain the reference temperature. Further, when the ambient temperature is between the upper limit temperature and the lower limit temperature, the output of the Peltier element becomes small, excessive cooling and heating are prevented, and the behavior that the temperature of the controlled portion rises and falls below the reference temperature. Therefore, the Peltier element is prevented from being frequently switched between the cooling operation and the heating operation, and deterioration of the Peltier element can be prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The overall configuration of a temperature control device exemplified in this embodiment is shown in FIG. 1, and controls a temperature of a circuit board 11 on which a semiconductor laser light source 10 is mounted as a controlled portion.

In FIG. 1, reference numeral 12 denotes a Peltier device;
Is a control temperature detecting means, which are both circuit board 11
Attached to. Specifically, the Peltier device 12
Is mounted in close contact with the semiconductor laser light source 10 of the circuit board 11, and the control temperature detecting means 13
The voltage dividing circuit has an output line extending from a common connection between the thermistor Rt1 and the resistor R3 mounted on the circuit board 11.

Reference numeral 15 denotes an ambient temperature detecting means, which constitutes a voltage dividing circuit extending an output line from a common connection portion of the thermistor Rt2 and the resistor R4, and is arranged near the circuit board 11 which is a controlled portion. The temperature of the air around the substrate 11 is output as a voltage signal.

Reference numeral 14 denotes a first reference voltage circuit, which includes a resistor R
A voltage dividing circuit is formed by extending an output line from a common connection portion of the first and the second R2, and outputs a first reference voltage corresponding to a "preset reference temperature" according to the present invention. In the present embodiment, the reference temperature is set to, for example, 25 ° C.

Amplifying means 100 amplifies the difference between the output of the control temperature detecting means 13 and the output of the first reference voltage circuit 14 by a differential amplifying circuit 101 and outputs the amplified signal to a half-wave circuit 102 and an absolute value circuit 103. I'm taking it.

The half-wave circuit 102 has the same configuration as a so-called half-wave rectifier circuit. When the voltage signal received from the differential amplifier circuit 101 is a positive voltage, the voltage signal is set as it is. Output to 104. The comparison circuit 104
It determines whether the voltage signal received from the half-wave circuit 102 is a positive voltage or zero, and outputs the result to the Peltier driver 106 as a binary digital signal. Note that the voltage applied to the + input terminal in the comparison circuit 104 has a certain offset width with respect to the zero potential in consideration of the fluctuation of the voltage signal from the half-wave circuit 102 and the like.

The absolute value circuit 103 has the same configuration as a so-called full-wave rectifier circuit, and outputs all the voltage signals received from the differential amplifier circuit 101 as positive voltage signals regardless of whether the voltage signal is positive or negative.

Reference numeral 105 denotes an amplifier circuit, which is an absolute value circuit 10.
3, and amplifies the voltage signal with an amplification factor determined based on the variable resistor Rx and outputs the amplified signal to the Peltier driver 106.

The Peltier driver 106 includes an IC (not shown), and switches the Peltier device 12 between a cooling operation and a heating operation based on a binary digital signal received from the comparison circuit 104. Also, the Peltier driver 106
Drives the Peltier element 12 with a drive current based on the voltage signal received from the amplifier circuit 105.

Now, this temperature control device includes an amplification circuit 1
An amplification factor determining means 200 for determining the amplification factor of the step 05 is provided. In this amplification factor determining means 200, 201
Denotes an upper limit reference circuit, which constitutes a voltage divider circuit extending an output line from a common connection portion of the resistors R5 and R6, and outputs an upper limit voltage corresponding to a "predetermined upper limit temperature" according to the present invention. Reference numeral 203 denotes a lower limit reference circuit, which includes resistors R7 and R7.
8 forms a voltage divider circuit extending the output line from the common connection portion, and outputs a lower limit voltage corresponding to the “predetermined lower limit temperature” according to the present invention. In the present embodiment, the upper limit temperature is set to, for example, 35 ° C., and the lower limit temperature is set to, for example, 10 ° C.

Reference numeral 202 denotes a high-temperature-side temperature comparing circuit, which outputs a voltage signal from the ambient temperature detecting means 15 and an upper-limit reference circuit 20.
The output signal is compared with the upper limit voltage output from 1 and the result is output as a binary signal.

Reference numeral 204 denotes a low-temperature-side temperature comparison circuit, which outputs a voltage signal from the ambient temperature detection means 15 and a lower-limit reference circuit 20.
The output signal is compared with the lower limit voltage output from No. 3 and the result is output as a binary signal.

Reference numeral 205 denotes an amplification factor determination circuit which changes the resistance value of the variable resistor Rx in the amplification circuit 105 based on the binary signal received from the comparison circuits 202 and 204 to amplify the signal. The amplification factor of the circuit 105 is switched between a low magnification and a high magnification. In the present embodiment, the low magnification is set to, for example, 1.8 times, and the high magnification is set to 2.times.
It is set to double.

In the present embodiment, specific numerical values of the upper limit temperature, the lower limit temperature, and the amplification factor (low magnification, high magnification) are experimentally obtained and set as follows. That is, first, the amplification factor of the amplification circuit 105 is fixed to the same low magnification as the fixed amplification factor in the conventional temperature control device, and control is performed with this fixed magnification so as to maintain the temperature of the controlled portion at the reference temperature. . At this time, data of the temperature of the controlled part is acquired while gradually increasing the ambient temperature, and the ambient temperature at which the controlled part cannot be maintained at the reference temperature with the output of the cooling operation of the Peltier element 12 is set as the upper limit temperature. The ambient temperature at which the controlled part cannot be maintained at the reference temperature with the output of the heating operation of (1) is set as the lower limit temperature.

Next, when the ambient temperature is set to the upper limit temperature or the lower limit temperature, the amplification factor of the amplification circuit 105 is changed to obtain data of the temperature of the controlled portion. Then, even if the ambient temperature exceeds the upper limit temperature or the lower limit temperature, and further reaches the maximum temperature or the minimum temperature of the ambient temperature that is the specification of the controlled part, the heating or cooling operation of the Peltier element 12 is performed. The setting value of the high magnification of the amplifier circuit 105 is determined so that the temperature of the controlled portion can be maintained at the reference temperature.

The amplification factor of the amplification circuit 105 of the present embodiment is configured to be switched between two stages of low magnification and high magnification, and is adapted when the ambient temperature is extremely high or low with respect to the reference temperature. Therefore, by providing the amplification factor in more stages, it is possible to adapt to a wider ambient temperature.

Next, the operation of this embodiment having the above configuration will be described with reference to FIG. When the semiconductor laser light source 10 is driven, the heat generated by the semiconductor laser light source 10 causes the temperature of the circuit board 11, which is the controlled portion of the present embodiment, to rise, and eventually becomes higher than the preset reference temperature Θ1 as shown in FIG. The temperature of the circuit board 11 is detected by the control temperature detecting means 13, and the detected signal and a first reference voltage (a voltage output from 14 in FIG. 1) corresponding to the reference temperature Θ1 are converted to a differential amplifier circuit 101. It is taken in. Here, since the temperature of the circuit board 11 is higher than the reference temperature Θ1, the control temperature detecting means 1
The detection signal of No. 3 becomes larger than the first reference voltage, and the temperature difference between the temperature of the circuit board 11 and the reference temperature # 1 is output from the differential amplifier circuit 101 as a positive voltage signal. Then, the signal passes through the half-wave circuit 102 and the comparison circuit 104 to become a signal for causing the Peltier element 12 to perform a cooling operation, and is given to the Peltier driver 106.

The voltage signal relating to the temperature difference output from the differential amplifier circuit 101 is obtained through the absolute value circuit 103 as the absolute value of the temperature difference. And the absolute value circuit 1
03 is amplified by the amplifier circuit 105 at a predetermined amplification rate to become a predetermined voltage signal, which is taken into the Peltier driver 106.

Here, as shown on the left side of FIG.
When the ambient temperature is equal to or lower than the upper limit temperature Θ2 and equal to or higher than the lower limit temperature Θ3, the detection signal of the ambient temperature detecting unit 15 is lower than the output voltage of the upper limit reference circuit 201 and higher than the output voltage of the lower limit reference circuit 203. . Then, the result is converted into a binary signal through both the comparison circuits 202 and 204, and is supplied to the amplification factor determination circuit 205. Then, the circuit 205 holds the amplification factor of the amplification circuit 105 at a low magnification, and as a result, a relatively small voltage signal is output from the amplification circuit 105.

Then, the Peltier driver 106 receiving this voltage signal drives the driving current (FIG. 2) corresponding to the voltage signal.
(Refer to the left side of (B)) flows into the input portion of the Peltier element 12 in a predetermined direction, and the Peltier element 12 is cooled with a small output. This prevents the Peltier device 12 from excessively cooling the controlled part, and as shown on the left side of FIG. 2A, the temperature of the circuit board 11 does not fall below the reference temperature Θ1 and stably. Maintained at reference temperature # 1. Here, in the present embodiment, by setting the reference temperature, the upper limit temperature, and the amplification factor to specific temperatures as described above, the temperature of the controlled portion (the circuit board 11) is maintained at, for example, about 26 ° C. However, the semiconductor laser light source 10 of the present embodiment
In the range of 5 ± 1 ° C., there is almost no change in the characteristics, so if the temperature of the circuit board 11 is 26 ° C.,
It can be determined that the temperature of No. 1 was maintained at the reference temperature # 1.

On the other hand, as shown on the right side of FIG. 2A, when the ambient temperature becomes higher than the upper limit temperature Θ2, the detection signal of the ambient temperature detecting means 15 becomes larger than the output voltage of the upper limit reference circuit 201. . Then, the result is given to the amplification factor determination circuit 205 through the high temperature side temperature comparison circuit 202, and the circuit 205 switches the amplification factor of the amplification circuit 105 to a high magnification. As a result, a relatively large voltage signal is output from the amplifier circuit 105. Then, the Peltier driver 106 receiving the voltage signal causes a drive current (see the right side of FIG. 2B) corresponding to the voltage signal to flow in a predetermined direction to an input portion of the Peltier element 12 and output a large output. To perform cooling operation. Thereby, the balance between the influence of the ambient temperature and the output of the Peltier element 12 is maintained, and the temperature of the controlled portion is maintained at the reference temperature Θ1, as shown on the right side of FIG.

As described above, according to the temperature control device of the present embodiment, even if the ambient temperature changes, the output of the Peltier element 12 is switched between large and small so as to cancel the change. ) Can be stably maintained at the reference temperature # 1. Further, when the ambient temperature is between the upper limit temperature and the lower limit temperature, the output of the Peltier element 12 decreases, preventing excessive cooling or heating, and causing a behavior in which the temperature of the controlled portion rises and falls below the reference temperature. Because it can be suppressed,
Frequent switching of the Peltier device 12 between the cooling operation and the heating operation is prevented, and deterioration of the Peltier device 12 can be prevented.

In the specific example described above, the Peltier element 12 is operated only to perform the cooling operation, and the temperature of the controlled part is maintained at the reference temperature. Only when the temperature of the controlled part is maintained at the reference temperature, and when the ambient temperature falls below the lower limit temperature, the amplification factor of the amplifier circuit 105 is increased to increase the output of the heating operation of the Peltier element 12. In some cases.

<Other Embodiments> The present invention is not limited to the above embodiments. For example, the following embodiments are also included in the technical scope of the present invention.
In addition to the following, various changes can be made without departing from the scope of the invention. (1) In the above embodiment, the circuit board 11 is used as a controlled part. However, the controlled part is not necessarily an electric product such as a circuit board, and may not generate heat. .

(2) In the above embodiment, only one upper limit temperature and one lower limit temperature are provided. For example, when the upper limit temperature and the lower limit temperature are set to a plurality, and the ambient temperature fluctuates, a plurality of times are set. It is also possible to adopt a configuration in which the amplification factor is changed by changing the gain. With such a configuration, the temperature of the controlled portion can be maintained at the reference temperature for an even wider ambient temperature.

[Brief description of the drawings]

FIG. 1 is a block diagram of a temperature control device according to an embodiment of the present invention.

FIG. 2A is a graph showing a change in temperature of a controlled part; FIG. 2B is a graph showing a change in a driving current applied to a Peltier element;

[Explanation of symbols]

11 Circuit board (controlled part) 12… Peltier element 13 ... Control temperature detecting means 15. Ambient temperature detection means 100 ... amplification means 200: amplification factor determining means Θ1… Reference temperature Θ2: Maximum temperature Θ3: Lower limit temperature

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 35/28 F25B 21/02

Claims (2)

(57) [Claims] 1. A Peltier device performs either one of heating and cooling operations to control a temperature of a controlled portion to be maintained at a preset reference temperature, and performs a cooling operation to the Peltier device. If so,
When the ambient temperature of the controlled portion is higher than or equal to a preset upper limit temperature, the output of the cooling operation of the Peltier element is increased, and when the Peltier element is performing a heating operation,
A temperature control method, wherein the output of the heating operation of the Peltier element is increased when the ambient temperature falls below a preset lower limit temperature. 2. A Peltier element, a control temperature detecting means for detecting a temperature of a controlled part, and a current corresponding to a temperature difference between a detection result of the control temperature detecting means and a preset reference temperature can be changed. Amplifying means for amplifying at a gain and applying the driving current to the Peltier device as the drive current, and causing the Peltier device to perform one of heating and cooling operations to maintain the temperature of the controlled portion at the reference temperature. An ambient temperature detecting means for detecting an ambient temperature of the controlled part, and an amplification factor determining means for determining an amplification factor of the amplifying means in response to a detection result of the ambient temperature detecting means. Means, the amplification factor determining means, when the Peltier element performs a cooling operation and when the ambient temperature becomes higher than a preset upper limit temperature, the Peltier element is heated When subjected to work and the ambient temperature is smaller than the lower limit temperature set beforehand, the temperature control apparatus characterized by increasing the amplification factor of said amplifying means.