Constant-temperature control using surroundings temperature of a device

• US 5,603,570 A
• Filed: 11/07/1994
• Issued: 02/18/1997
• Est. Priority Date: 11/05/1993
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Shimizu, Haruhito
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): Amrozowicz, Paul D.
• Application Number:
  US08/335,075
• Time in Patent Office: 834 Days
• Field of Search: 374/100, 374/152, 374/141, 374/210, 364/557
• US Class Current: 374/100
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: H01S 5/02251 using optical fibres
• CPC Class Codes: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/02415 by using a thermo-electric cooler [TEC], e.g. Peltier element
• CPC Class Codes: H01S 5/02438 Characterized by cooling of elements other than the laser chip, e.g. an optical element being part of an external cavity or a collimating lens
• CPC Class Codes: H01S 5/06804 by monitoring an external parameter, e.g. temperature
• CPC Class Codes: H01S 5/0687 Stabilising the frequency of the laser

Abstract

The temperature control of a device incorporated in a module is performed using a device temperature and a surroundings temperature of the device. The device temperature is detected by a device temperature sensor disposed near the device and the surroundings temperature is detected by a surroundings temperature sensor disposed on the module. Using the surroundings temperature when the device is operated, an actual temperature difference between the device temperature and a predetermined control target temperature is estimated based on a predetermined relation between the surroundings temperature and the device temperature detected when desired characteristics of the device are obtained. The device temperature detected when the device is operated is compensated with the estimated temperature difference to adjust the temperature of the device on the predetermined control target temperature.

Claims

1. A temperature control method of a device incorporated in a module, comprising the steps of:

detecting a device temperature when the device is operated, the device temperature being detected by a first sensor provided near the device;

detecting a surroundings temperature of the device when the device is operated, the surroundings temperature being detected by a second sensor provided to the module;

estimating a temperature difference between the device temperature and a predetermined control target temperature, based on the surroundings temperature and a predetermined correlation between the surroundings temperature and the device temperature detected when desired characteristics of the device are obtained;

compensating the device temperature detected when the device is operated with the temperature difference; and

adjusting the temperature of the device on the predetermined control target temperature based on the compensated device temperature;

the predetermined correlation is obtained by the steps of;

assembling the module including the device, the first sensor, the second sensor, and a temperature adjustment element for adjusting the temperature of the device at a predetermined arrangement;

driving the temperature adjustment element so that the characteristics of the device become consistent with the desired characteristics under a plurality of surroundings temperatures;

detecting the device temperature using the first sensor each time the characteristics of the device are consistent with the desired characteristics at each surroundings temperature; and

determining the correlation between the surroundings temperature and the device temperature.

2. The method as set forth in claim 1, wherein the step of estimating the temperature difference includes the steps of:

subtracting the predetermined control target temperature from the device temperature of the predetermined correlation to obtain a relation between the temperature difference and the surroundings temperature; and

estimating the temperature difference using the relation and the surroundings temperature when the device is operated.

3. The method as set forth in claim 2, wherein the relation is expressed by a function formula.

4. A temperature control method of a device incorporated in a module, comprising the steps of:

detecting a device temperature when the device is operated, the device temperature being detected by a first sensor provided near the device;

detecting a surroundings temperature of the device when the device is operated, the surroundings temperature being detected by a second sensor provided to the module;

estimating a temperature difference between the device temperature and a predetermined control target temperature, based on the surroundings temperature and a predetermined correlation between the surroundings temperature and the device temperature detected when desired characteristics of the device are obtained;

compensating the device temperature detected when the device is operated with the temperature difference; and

adjusting the temperature of the device on the predetermined control target temperature based on the compensated device temperature;

the step of estimating the temperature difference includes the steps of;

subtracting the predetermined control target temperature from the device temperature of the predetermined correlation to obtain a relation between the temperature difference and the surroundings temperature; and

estimating the temperature difference based on the relation and the surroundings temperature when the device is operated.

5. The method as set forth in claim 4, wherein the relation is expressed by a function formula.

6. A temperature control system of a device incorporated in a module, comprising:

first detecting means provided near the device for detecting a device temperature;

second detecting means provided to the module for detecting a surroundings temperature of teh device;

estimating means for estimating a temperature difference between the device temperature detected by the first detecting means and predetermined control target temperature, based on the surroundings temperature detected when the device is operated and a predetermined correlation between the surroundings temperature and the device temperature detected when desired characteristics of the device are obtained; and

adjusting means for adjusting the temperature of the device to the predetermined control target temperature, based on the device temperature compensated with the estimated temperature difference;

the module including a housing containing the device and the first detecting means, and the second detecting means is provided on the surface of the module.

7. A temperature control system of a device incorporated in a module, comprising:

first detecting means provided near the device for detecting a device temperature;

second detecting means provided to the module for detecting a surroundings temperature of the device;

estimating means for estimating a temperature difference between the device temperature detected by the first detecting means and predetermined control target temperature, based on the surroundings temperature detected when the device is operated and a predetermined correlation between the surroundings temperature and the device temperature detected when desired characteristics of the device are obtained; and

adjusting means for adjusting the temperature of the device to the predetermined control target temperature, based on the device temperature compensated with the estimated temperature difference;

the estimating means including;

storage means for storing a relation between the temperature difference and the surroundings temperature, the temperature difference being obtained by subtracting the predetermined control target temperature from the device temperature of the predetermined correlation; and

readout means for reading out the temperature difference from the storage means according to the surroundings temperature detected when the device is operated.

8. The temperature control system as set forth in claim 7, wherein the module includes a housing containing the device and the first detecting means, and the second detecting means is provided on the surface of the module.

9. A temperature control system of a device incorporated in a module, comprising:

first detecting means provided near the device for detecting a device temperature;

second detecting means provided to the module for detecting a surroundings temperature of the device;

estimating means for estimating a temperature difference between the device temperature detected by the first detecting means and predetermined control target temperature, based on the surroundings temperature detected when the device is operated and a predetermined correlation between the surroundings temperature and the device temperature detected when desired characteristics of the device are obtained; and

adjusting means for adjusting the temperature of the device to the predetermined control target temperature, based on the device temperature compensated with the estimated temperature difference the estimating means including;

storage means for storing a function formula expressing a relation between the temperature difference and the surroundings temperature, the temperature difference being obtained by subtracting the predetermined control target temperature from the device temperature of the predetermined correlation; and

calculation means for calculating the temperature difference using the function formula stored in the storage means and the surroundings temperature detected when the device is operated.

10. The temperature control system as set forth in claim 9, wherein the module includes a housing containing the device and the first detecting means, and the second detecting means is provided on the surface of the module.

11. A temperature control system of a device incorporated in a module, comprising:

first detector provided near the device for detecting a device temperature;

second detector provided to the module for detecting a surroundings temperature of the device;

estimating device to estimate a temperature difference between the device temperature detected by the first detector and a predetermined control target temperature, based on the surroundings temperature detected when the device is operated and a predetermined correlation between the surroundings temperature and the device temperature detected when desired characteristics of the device are obtained; and

adjusting device to adjust the temperature of the device to the predetermined control target temperature, based on the device temperature compensated with the estimated temperature difference;

the module includes a housing containing the device and the first detector and the second detector is provided on the surface of the module.

12. A temperature control system of a device incorporated in a module, comprising:

first detector provided near the device for detecting a device temperature;

second detector provided to the module for detecting a surroundings temperature of the device;

estimating device to estimate a temperature difference between the device temperature detected by the first detector and a predetermined control target temperature, based on the surroundings temperature detected when the device is operated and a predetermined correlation between the surroundings temperature and the device temperature detected when desired characteristics of the device are obtained; and

adjusting device to adjust the temperature of the device to the predetermined control target temperature, based on the device temperature compensated with the estimated temperature difference;

the estimating device including;

storage device for storing a relation between the temperature difference and the surroundings temperature, the temperature difference being obtained by subtracting the predetermined control target temperature from the device temperature of the predetermined correlation; and

readout device for reading out the temperature difference from the storage device according to the surroundings temperature detected when the device is operated.

13. The temperature control system as set forth in claim 12, wherein the module includes a housing containing the device and the first detector, and the second detector is provided on the surface of the module.

14. A temperature control system of a device incorporated in a module, comprising:

first detector provided near the device for detecting a device temperature;

second detector provided to the module for detecting a surroundings temperature of the device;

estimating device to estimate a temperature difference between the device temperature detected by the first detector and a predetermined control target temperature, based on the surroundings temperature detected when the device is operated and a predetermined correlation between the surroundings temperature and the device temperature detected when desired characteristics of the device are obtained; and

adjusting device to adjust the temperature of the device to the predetermined control target temperature, based on the device temperature compensated with the estimated temperature difference;

the estimating device including;

storage device for storing a function formula expressing a relation between the temperature difference and the surroundings temperature, the temperature difference being obtained by subtracting the predetermined control target temperature from the device temperature of the predetermined correlation; and

calculation device for calculating the temperature difference using the function formula stored in the storage device and the surroundings temperature detected with the device is operated.

15. The temperature control system as set forth in claim 14, wherein the module includes a housing containing the device and the first detector and the second detector is provided on the surface of the module.