JPH0449555Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an infrared detector used for measuring object surface temperature, atmospheric temperature, human body detection, etc.

[Conventional technology]

2. Description of the Related Art Conventionally, an infrared detector consisting of a combination of a metal foil and a heat-sensitive element fixed to one surface of the metal foil has been used as a temperature control sensor for air conditioning equipment. The above-mentioned infrared detector is a thermal sensor that uses a fixed element such as a thermistor or pyroelectric effect element whose electrical characteristics change as it absorbs infrared rays. The value of the difference between the infrared energy and the infrared energy emitted by the detector itself is obtained as the detection output.

Conventionally, the above-mentioned infrared detectors have been made using a single chip of metal foil with a heat-sensitive element attached and fixed on a heat insulating material (Utility Model Application Publication No. 59-151127), or a metal foil chip with a heat-sensitive element attached to the lead terminal of the electrode. There are some known examples that have been installed.

[Problem that the invention attempts to solve]

The metal foils used in conventional infrared detectors all have a small area and low heat capacity, and are used exclusively to locally measure temperature using an optical system. If the metal foil is in the form of a chip with a small area, there will be almost no variation in temperature distribution, and no special problems will arise in handling it as a single chip or assembling it into a case. However, in order to expand the heat receiving area and measure the average temperature in a wide range of the outside world, it is necessary to eliminate unevenness in temperature distribution over the entire heat receiving surface of the metal foil, and to have a heat insulating support mechanism that prevents heat dissipation from the metal foil. is an important issue. Furthermore, since the metal foil itself is a source of infrared radiation, a thermally stable support structure including a heat insulating structure is particularly required.

The purpose of the present invention is to provide a support structure for a heat receiving plate that increases the heat receiving area and maintains the thermal stability of the enlarged heat receiving plate.

[Means for solving problems]

This invention is an infrared detector that has a filter that transmits infrared energy emitted from a target object, a heat receiving plate made of a good thermal conductor whose surface is a black body, and a heat sensitive element fixed to the heat receiving plate. The peripheral edge of the heat receiving plate was supported on a heat insulating support having a recess, the heat sensitive element was housed in the recess, and the heat receiving plate was positioned in an air chamber composed of a filter and a heat insulating support. This is an infrared detector characterized by the following.

〔Example〕

Embodiments of the present invention will be described below using figures.

1 to 3, the infrared detector of the present invention includes a filter 3 that transmits infrared energy emitted from a target object, a black body surface,
A heat-receiving plate 4 made of a metal with good thermal conductivity and having a heat-sensitive element 9 fixed on one side is stacked on top of the other, and this is supported on a heat-insulating support base 7 having a recess 8 in the center. The heat-sensitive element 9 is housed in the recess 8, and the opening edge of the recess 8 is covered with the heat receiving plate 4 to form an air chamber therein. In the following embodiment, a case will be described in which this assembly is assembled into the case 2.

In the embodiment, the case 2 uses a combination of a frame 6 with a rectangular window hole 1 and the heat insulating support 7, supports the filter 3 and the heat receiving plate 4, and supports the support 7 on the frame 6. An example is shown in which it is fitted into the rear opening edge of. The filter 3 is made of a thin film of polyethylene, silicon, polystyrene, etc.
This is attached to one surface of the heat receiving plate 4 with an air layer interposed therebetween.

The heat receiving plate 4 is a metal plate made of aluminum, copper, or the like with excellent thermal conductivity and small heat capacity, and its surface is subjected to black body treatment using an insulator. On the other side of this heat receiving plate 4, a thermistor, a pyroelectric effect element,
A thermosensitive element 9, such as a thermocouple, whose electrical characteristics change with temperature changes, is fixed using an adhesive such as epoxy resin. Furthermore, if necessary, a heater element 10 is attached to the plate surface of the heat receiving plate 4 separately from this heat sensitive element 9.
to be fixed. The filter 3 is attached to the heat receiving plate 4 via an air layer, and band-shaped heat insulating materials 5, 5 are attached to the front and back sides of the heat insulating frame edge 11 that supports the peripheral edge of the heat receiving plate 4, and this is used as a unit to form the frame pair 6. The heat receiving plate 4 is pressed into contact with the support base 7 made of a heat insulating material fitted into the frame body 6, and the unit is sandwiched between the frame body 6 and the support base 7. The peripheral edge is supported on the support stand 7, and the heat receiving plate 4 is supported as described above.
The heat sensitive element 9 and the heater element 10 attached to the recess 8 are received in the recess 8, and the opening edge of the recess 8 is inserted into the heat receiving plate 4.
The lid is closed to form an air chamber inside. In addition, in order to improve the thermal insulation between the heat receiving plate 4 and the case 2, the four corners of the heat receiving plate 4 are provided with frame edges 11.
It is desirable that the heat conduction area to the case 2 be reduced by forming a gap d at the outer edge of each side.

On the other hand, the lead wires 12 of the heat-sensitive element 9 and heater element 10 attached to the heat-receiving plate 4 are connected to a socket 13 using thin wires, and the socket 13 is connected to a fitting edge 14 formed in a part of the frame 6. to be locked.

In the embodiment, infrared energy from the object to be measured is absorbed by the heat receiving plate 4, which is incident through the filter 3 facing the window hole 1 of the case 2. Conversely, since the heat-receiving plate 4 itself is an infrared radiation source, infrared energy is radiated to the surroundings, and as the temperature of the heat-receiving plate 4 changes based on the difference in energy, the electrical characteristics of the heat-sensitive element 9 change, and its value changes. is taken out as the detection output. If necessary, the heater element 10 is energized to heat the heat receiving plate 4 and maintain it at a constant temperature.

In this case, the peripheral edge of the heat receiving plate 4 is supported by the support stand 7, and almost the entire back surface of the heat receiving plate 4 is in contact with the air trapped in the recess 8 of the support stand 7, so that the temperature of the entire surface is stabilized in a steady state. Even when a large-diameter heat receiving plate 4 is used, local unevenness in temperature distribution does not occur, and highly accurate detection output can be obtained by quickly responding to external temperature changes due to incident infrared rays.

Furthermore, in the present invention, the structure of the case is not limited to the above embodiments. 4 and 5 are examples in which a combination of a filter and a heat receiving plate is housed in a hollow container, and the hollow container is covered with a lid having a window hole. That is, first, a support base 17 made of a heat insulating material and having a recess 16 at the center of the upper surface is inserted into the hollow container 15, and the filter 3 is placed on the support base 17.
The heat-sensitive element 9 and heater element 10 fixed to the heat-receiving plate 4 by setting the combination of the filter 3 and the heat-receiving plate 4 are positioned in the recess 16 of the support base 17, and the upper periphery of the filter 3 is held down by an annular heat insulating material 18. It is closed with a lid body 20 having a window hole 19. In this embodiment as well, the peripheral edge of the heat receiving plate 4 is supported by the support stand 17, and the recess 16 of the support stand 17 is covered by the heat receiving plate 14 to form air pressure inside. The heat sensitive element 9 and the heater element 10 are housed in the recess 16 of the support base 17. The lead wires 21 of the heat sensitive element 9 and the heater element 10 are led out through the wall of the hollow container 15.

The operation and effect of this embodiment are exactly the same as those of the previous embodiment.

[Effect of idea]

As described above, according to the present invention, the peripheral edge of the heat receiving plate is supported on a support made of a heat insulating material, and a closed air chamber is formed in the recess provided in the center of the support, so that even if the heat receiving plate has a large diameter, The heat receiving plate can be supported stably by preventing heat dissipation even when the heat is dissipated, and the heat receiving plate is affected by the temperature of the air layer within the confined recess, preventing local temperature distribution unevenness and maintaining thermal stability. This has the effect of expanding the viewing angle and improving the axial radiation sensitivity.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing one embodiment of the present invention, Fig. 2 is a perspective view showing an assembled state, Fig. 3 is a vertical sectional view of the same, Fig. 4 is an exploded perspective view showing another embodiment, Fifth
The figure is a sectional view showing the assembled state. 4...Heat receiving plate, 7...Support stand, 8...Recess, 9
...Heat-sensitive element.

Claims (1)

[Scope of utility model registration request] An infrared detector has a filter that transmits infrared energy emitted from a target object, a heat receiving plate made of a good thermal conductor with a black body surface, and a heat sensitive element fixed to the heat receiving plate, and a recessed portion is provided in the center. The peripheral edge of the heat receiving plate is supported on a heat insulating support base provided with a heat receiving plate, the heat sensitive element is accommodated in the recess, and the heat receiving plate is positioned in an air chamber composed of a filter and a heat insulating support base. Features an infrared detector.