TWI603101B - Thermostat - Google Patents

Description

Thermostat

The present invention relates to a thermostat for use in a temperature accelerated life test of an LED (Light Emitting Diode).

Although LED is a light source with a long life, the current situation is that its brightness is slowly attenuated as the lighting time increases. Therefore, as one of the evaluation methods of the life of the LED, the specification of the "IES LM-80" developed by the "North American Lighting Engineering Association" is known. This specification is a maintenance rate (light flux maintenance ratio) of the test luminance to the lighting time of the LED, and the LED lifetime is evaluated based on whether or not the test result is equal to or higher than the constant value.

Specifically, the test method is to continuously illuminate for 6000 hours under the three temperature conditions of 55 ° C, 85 ° C and any temperature determined by the manufacturer (up to 125 ° C) for the test body LED driven by the same current value ( 250 days), the brightness of the LED was measured every 1000 hours. In the case of such a test, it is necessary to maintain the LED as a test body at a constant temperature for a long period of time, and a hot air circulation type thermostatic bath has been conventionally used.

However, in the case where the LED as the test body is placed in a hot air circulating type thermostat, the heat circulating in the thermostat is maintained in order to maintain the temperature. The wind blows directly onto the LED, so it may have an adverse effect on the test results. Further, in the conventional hot air circulating type thermostatic bath, since the uniformity of the temperature distribution in the tank is poor, when a plurality of LEDs are housed, the test accuracy may be lowered.

On the other hand, as a device for performing a temperature accelerated life test of an LED, many types of test devices have been proposed, and the device related to the present invention is, for example, a test device disclosed in Patent Document 1.

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2011-179937

In the LED life test device disclosed in Patent Document 1, since one test LED is placed in a HAST device and tested, the temperature distribution is excellent in uniformity, but the device is caused by the hot wire component contained in the light of the continuously emitted LED. The temperature inside rises above the set temperature and adversely affects the test results. The higher the output of the LED to be tested (higher brightness), the more remarkable the situation is. Therefore, in recent years, it has become difficult to perform accurate life testing on an LED having a high luminance.

An object of the present invention is to provide a thermostat which can maintain an LED in an atmosphere which is stable at a uniform temperature in a temperature accelerated life test of an LED and has a simple structure.

The thermostat according to the present invention includes: a constant temperature plate having a heating means and a cooling means, a test body loading table provided on the constant temperature plate, and a light transmission disposed to cover the test body loading table. a top member, as the above heating means, is provided with heating the above constant temperature As the heating element of the plate, as the cooling means, a blower fan that air-cools the above-mentioned constant temperature plate is provided.

Here, it is preferable that a heat sink is provided between the thermostat plate and the blower fan.

Further, a cooling air supply means for supplying a cooling gas to the air blowing fan may be provided.

Furthermore, it is also possible to form a thermostat capable of simultaneously performing a temperature accelerated life test of a plurality of LEDs by arranging a plurality of the above-described thermostats and providing an opening and closing cover for covering the upper surfaces of the plurality of thermostats.

According to the present invention, it is possible to provide a thermostat which can maintain an LED in an atmosphere which is stable at a uniform temperature and has a simple structure in the temperature accelerated life test of the LED.

10‧‧‧ thermostat

11, 31‧‧‧ electric heating body

12a, 12b‧‧‧Locking members

20‧‧‧Test body loading platform

20a, 20b‧‧‧ gap

30‧‧‧ partition member

30a‧‧‧ openings

40‧‧‧ top member

50‧‧‧Air supply fan

60‧‧‧ radiator

Fig. 1 is a partially omitted perspective view showing a thermostat according to an embodiment of the present invention.

Fig. 2 is a partially omitted front elevational view of the thermostat shown in Fig. 1.

Fig. 3 is a partially omitted perspective view of the thermostat shown in Fig. 1.

Hereinafter, embodiments of the present invention will be described based on the drawings. As shown in FIG. 1 to FIG. 3, the thermostat 100 of the present embodiment is provided with a built-in The thermostatic plate 10 of the electric heating element 11 of the thermal device; the test body loading table 20 provided on the thermostatic plate 10; and the flat-shaped partition wall which is disposed on the thermostatic plate 10 and has an opening 30a surrounding the test body loading table 20 The member 30; and a translucent heat-resistant glass top member 40 disposed on the partition member 30 in a state of covering the test body loading table 20 and the opening 30a. In the present embodiment, the electric heating element 31 is also built in the partition member 30. 1 and 3 show a state in which the top member 40 is detached.

Moreover, as a cooling means of the thermostat plate 10, the blower fan 50 which air-cools the thermostat plate 10 is provided below the thermostat plate 10. The heat sink 60 is disposed between the thermostat plate 10 and the blower fan 50 in a state of being in close contact with the lower surface of the thermostat plate 10, and the blower fan 50 is disposed on the lower surface side of the heat sink 60.

Further, in order to detachably lock the top member 40 placed on the partition member 30 on the left and right side surfaces of the thermostat plate 10, a pair of locking members 12a and 12b having an L-shaped cross section are disposed in a facing shape. Further, although not shown, in order to increase the cooling action by the cooling fan 50, a cold air supply device that supplies the cooling gas to the blower fan 50 may be provided. In addition, a vent hole may be provided in the top member 40.

As shown in Fig. 1, a plurality of cutout portions 20a and 20b are provided on the peripheral portion of the test body loading table 20 for supplying a power supply line (not shown) for the LEDs placed on the test object loading table 20 and measuring LEDs. The signal line (not shown) of the temperature sensor of the temperature is wired.

Furthermore, in the thermostat device 100, the test body loading table 20 and the opening The shape of the portion 30a is substantially circular, but the shape is not limited thereto, and other shapes (for example, a square shape, an elliptical shape, a polygonal shape, or the like) may be adopted.

When the thermostat device 100 is used, as shown in FIGS. 1 and 3, the top member 40 (see FIG. 2) is opened, and the LED as a test body is placed on the test body loading table 20, respectively, on the power supply line and After the signal lines of the temperature sensor are wired, the top member 40 is closed and the top member 40 is locked with the locking members 12a, 12b. Thereafter, the electric heating elements 11 and 31 of the thermostat plate 10 and the partition member 30 are started to be supplied with power. Thereby, the LED on the test body loading table 20 rises to a preset temperature (for example, 55 ° C, 85 ° C or 125 ° C) and is maintained at this temperature.

On the other hand, when the test body loading table 20 and the vicinity of the LEDs are to exceed the set temperature by the continuous lighting of the LEDs, the blower fan 50 is automatically activated, and the air is blown to the heat sink 60, and the heat is dissipated by the heat sink 60. The thermostat plate 10 is cooled. Further, when the test body loading table 20 and the vicinity of the LED are lowered to the set temperature, the blower fan 50 is automatically stopped. In this way, since the blower fan 50 is automatically opened and closed corresponding to the temperature in the vicinity of the test body loading table 20 and the LED, overheating or overcooling of the test body loading table 20 and the LED can be prevented, and high temperature accuracy can be maintained. Moreover, since the blower fan 50 which is a cooling means of the thermostat plate 10 does not require a liquid supply path and a liquid discharge path for supplying a coolant, the structure is also simple.

Thus, in the thermostat device 100, the test body loading table 20 and the LED are separated from the atmosphere by the partition member 30 and the top member 40, and the constant temperature plate 10 and the partition member 30 having the heating function are continuously heated to both. The temperature is set so that the LED placed on the test body loading table 20 can be held in an atmosphere that is stable at a uniform temperature. Therefore, the temperature accelerated life test of the LED can be performed with high precision and high efficiency. Further, if a vent hole (not shown) is formed in the top member 40 to maintain air permeability, it is effective in preventing overheating of the LED.

Further, although not shown, if a plurality of thermostats 100 are arranged vertically and horizontally, and an open-close type cover or the like for covering the upper surfaces of the plurality of thermostats 100 is provided, it is possible to form a temperature accelerated life test capable of simultaneously performing a plurality of LEDs. Thermostat.

The thermostat 100 described with reference to FIGS. 1 to 3 is an apparatus showing an example of the present invention, and the thermostat according to the present invention is not limited to the above-described thermostat 100.

Industrial availability

The thermostat of the present invention can be widely used in fields such as the electronics and motor industry or the mechanical industry where various temperature accelerated life tests of LEDs are performed.

10‧‧‧ thermostat

11‧‧‧Electrical heating element

12a, 12b‧‧‧Locking members

20‧‧‧Test body loading platform

20a, 20b‧‧‧ gap

30‧‧‧ partition member

30a‧‧‧ openings

31‧‧‧Electrical heating element

50‧‧‧Air supply fan

60‧‧‧ radiator

100‧‧‧Constant thermostat

Claims (3)

A thermostat device comprising: a thermostat plate having a heating means and a cooling means; a test body loading table provided on the thermostat plate; and a translucent heat-resistant glass disposed to cover the test body loading table In the top member, as the heating means, a heat generating body that heats the constant temperature plate is provided in the constant temperature plate, and as the cooling means, a blower fan that air-cools the constant temperature plate is provided adjacent to the constant temperature plate. The thermostat according to claim 1, wherein a heat sink is disposed between the thermostat and the blower fan. The thermostat according to claim 1 or 2, wherein a cold air supply means for supplying a cooling gas to the blower fan is provided.