JPH1038695A - Infrared detecting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of the detecting sensitivity of an infrared detecting element even when the leads for supplying current and measuring voltage of the element are made thin and long by separately providing the leads. SOLUTION: A lead 8a for supply current, a lead 9a for measuring voltage, and leads 8b and 9b are faced oppositely in the direction perpendicular to antennas 3a and 3b and connected to a bolometer 2. The electrodes 10a and 11a connected to the leads 8a and 9a are connected to a constant-current source and the electrodes 10b and 11b connected to the leads 8b and 9b are connected to a voltmeter. When the input resistance of the voltmeter is large due to the relation between the resistance values of the bolometer 2 and leads and the output voltage of the voltmeter when an infrared detecting element is irradiated with infrared rays and not irradiated with the infrared rays, the constant current from the constant-current source does not flow to the leads 9a and 9b, but to the bolometer 2. Therefore, the sensitivity of the output voltage of the voltmeter becomes irrespective of the resistance values of the leads 9a and 9b . Since the leads for supplying current and measuring voltage are separately provided, the deterioration of the detecting sensitivity of the detecting element can be prevented even when each lead is made thin and long for preventing the influence of the characteristics of the antennas 3a and 3b .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an infrared detector using an antenna and a bolometer, and more particularly to an infrared detector having improved detection sensitivity.

[0002]

2. Description of the Related Art A bolometer converts the energy of infrared electromagnetic waves into heat, and detects a change in temperature as a change in resistance. Then, an infrared detecting element is formed by forming a bolometer as a thin film on the substrate.

[0003] In addition, there has been another problem that the heat flux escapes from the bolometer to the substrate during the irradiation of infrared rays to lower the detection sensitivity.

Here, in order to prevent a decrease in sensitivity, even if the bolometer is reduced to reduce the area where the heat flux escapes to the substrate, the area for receiving infrared rays also decreases, so that the sensitivity decreases.

In order to solve such a problem, there has been an example in which an infrared ray is received using an antenna, and the received power is converted into thermal energy using a bolometer provided in a power supply unit to detect the infrared ray.

FIG. 3 is a configuration diagram showing an example of such a conventional infrared detecting element. In FIG. 3, 1 is a substrate, 2 is a bolometer, 3a and 3b are antennas, 4a and 4b are leads, 5a and 5b are electrodes, 6 is a voltmeter, 7 is a constant current source, and 100 is an infrared ray.

A thin-film bolometer 2 is formed on a substrate 1, and a pair of linear antennas 3 a and 3 b are provided on the bolometer 2 so as to face each other.

Further, a lead 4a and a lead 4b are provided so as to face each other in a direction perpendicular to the antennas 3a and 3b,
One ends of the leads 4a and 4b are connected to the bolometer 2, respectively, and the other ends are provided with electrodes 5a and 5b, respectively. A voltmeter 6 and a constant current source 7 are connected to the electrodes 5a and 5b.

Now, the operation of the conventional example shown in FIG. 3 will be described. The infrared light 100 incident on the infrared detection element is received by the antennas 3a and 3b. The bolometer 2 converts the received energy of the electromagnetic wave of the infrared ray 100 into heat, and uses this temperature change as a resistance value change.

Therefore, the electrodes 5a and 5a
b, a constant current is supplied to the bolometer 2 via the leads 4a and 4b, and the voltage between the electrodes 5a and 5b is detected by the voltmeter 6, so that the infrared rays 100 can be detected.

As a result, even if the bolometer 2 is made smaller in order to prevent a decrease in the detection sensitivity due to the heat flux escaping to the substrate, the area for receiving the infrared rays 100 does not change, so that a decrease in the detection sensitivity can be prevented.

In addition, there is also an effect that the response capacity is increased by reducing the heat capacity by reducing the volume of the bolometer 2.

[0013]

However, in the conventional example shown in FIG. 3, the characteristics of the antennas 3a and 3b are easily affected by the leads 4a and 4b and the electrodes 5a and 5b. It is necessary to separate 5a and 5b from antennas 3a and 3b.

For this reason, in the conventional example, the leads 4a and 4b
Makes the resistances of the leads 4a and 4b increase.

Here, the resistance value of the bolometer 2 when the infrared ray 100 is irradiated and not irradiated is “R” and “R + ΔR”, the resistance value of the leads 4a and 4b is “RL”, The output voltage between the electrodes is "V" and "V
+ ΔV ”and the constant current as“ I ”, a relational expression of V = (2RL + R) · I (1) V + ΔV = (2RL + R + ΔR) · I (2) holds.

From the equations (1) and (2), the output voltage sensitivity "
ΔV / V ″ becomes ΔV / V = ΔR / (2RL + R) (3)

That is, from the formula (3), the leads 4a and 4
When the resistance value of “b” increases, the output voltage sensitivity decreases and the detection sensitivity decreases. Therefore, a problem to be solved by the present invention is to realize an infrared detecting element capable of preventing a decrease in detection sensitivity.

[0018]

In order to achieve the above object, according to a first aspect of the present invention, an infrared ray is received by using an antenna, and the received power is converted into thermal energy by a bolometer, and the temperature is converted to thermal energy. In an infrared detection element that detects a change as a resistance change, a bolometer formed on a substrate, a pair of antennas connected to the bolometer,
The bolometer includes a pair of current supply leads for supplying a current to the bolometer, and a pair of voltage measurement leads for extracting a voltage generated at the bolometer end to the outside when the current is supplied.

In order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, a pair of the antennas connected to the bolometer and provided to face each other, and a pair of the antennas are provided. A pair of current supply leads and a pair of voltage measurement leads are provided so as to be opposed to each other in a right angle direction.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a plan view showing one embodiment of the infrared detecting element according to the present invention.

In FIG. 1, reference numerals 2, 3a and 3b denote the same reference numerals as in FIG. 3, reference numerals 8a and 8b denote current supply leads (hereinafter simply referred to as leads), and reference numerals 9a and 9b denote voltage measurement leads ( Hereinafter, it is simply called a lead.) 10a, 1
0b, 11a and 11b are electrodes. In FIG. 1, the substrate, the voltmeter, and the constant current source are not shown.

The bolometer 2 formed on a substrate (not shown) is provided with a pair of linear antennas 3a and 3b facing each other.

Further, leads 8a and 9a and leads 8b and 9b are provided opposite to each other in a direction perpendicular to the antennas 3a and 3b, and one ends of the leads 8a, 8b, 9a and 9b are connected to the bolometer 2 respectively. .

On the other hand, electrodes 10a and 11a are provided at the other ends of the leads 8a and 9a, and electrodes 10b and 11b are provided at the other ends of the leads 8b and 9b, respectively.

A constant current source (not shown) is connected to the electrodes 10a and 10b, and a voltmeter (not shown) is connected to the electrodes 11a and 11b.

The operation of the embodiment shown in FIG. 1 will now be described with reference to FIG. FIG. 2 is a circuit diagram showing an equivalent circuit of FIG.

In FIG. 2, 12 and 14 are the equivalent resistances of the leads 8a and 8b, 13 is the equivalent resistance of the bolometer 2, 1
5 and 16 are equivalent resistances of the leads 9a and 9b, 17 is a constant current source, 18 is a voltmeter, and 100 is an infrared ray.

One end of the constant current source 17 is connected to one end of the equivalent resistance 12, and the other end of the equivalent resistance 12 is connected to one ends of resistors 13 and 15. The other end of the resistor 15 is connected to one end of a voltmeter 18, and the other end of the voltmeter 18 is connected to one end of an equivalent resistor 16.

The other end of the equivalent resistance 16 is connected to the other end of the equivalent resistance 13 and one end of the equivalent resistance 14, and the other end of the equivalent resistance 14 is connected to the other end of the constant current source 17.

As described above, the resistance value of the equivalent resistance 13 (bolometer 2) when the infrared ray 100 is irradiated and not irradiated is set to "
R ”and“ R + ΔR ”, and the resistance values of the equivalent resistances 12, 14, 15 and 16 (leads 8a, 8b, 9a and 9b) are“
RL '", voltmeter 1 with and without irradiation of infrared 100
Assuming that the output voltage at 8 is “V” and “V + ΔV” and the constant current is “I”, V = R · I (4) V + ΔV = (R + ΔR) · I (5)

That is, as can be seen from the equations (4) and (5), if the input resistance of the voltmeter 18 is sufficiently large, the constant current "I" does not flow through the equivalent resistances 15 and 16, and Since it flows, the voltage drop at the leads 9a and 9b is negligible.

Therefore, from the equations (4) and (5), the output voltage sensitivity “ΔV / V” becomes ΔV / V = ΔR / R (6), and does not depend on the resistance values of the leads 9a and 9b.

As a result, the leads 8a, 8b, 9a and 9b are provided to prevent influence on the characteristics of the antennas 3a and 3b by providing two pairs of leads and separating the current supply and voltage measurement leads. , The detection sensitivity can be prevented from lowering.

In addition to preventing the influence on the characteristics of the antenna, it also copes with adverse effects such as a reduction in detection sensitivity due to an increase in the resistance value due to the adaptation to high frequencies and the miniaturization of the lead wire width accompanying the high integration. Will be possible.

In the description of FIG. 1, 8a and 8b are current supply leads, and 9a and 9b are voltage measurement leads.

[0036]

As is apparent from the above description,
According to the present invention, the following effects can be obtained. By providing two pairs of leads and separating the current supply and voltage measurement leads, it is possible to realize an infrared detecting element capable of preventing a decrease in detection sensitivity.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of an infrared detecting element according to the present invention.

FIG. 2 is a circuit diagram showing an equivalent circuit of FIG.

FIG. 3 is a configuration diagram illustrating an example of a conventional infrared detection element.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 bolometer 3a, 3b antenna 4a, 4b lead 5a, 5b, 10a, 10b, 11a, 11b electrode 6, 18 voltmeter 7, 17 constant current source 8a, 8b current supply lead 9a, 9b voltage measurement lead 12 , 13,14,15,16 Equivalent resistance 100 infrared

Claims (2)

[Claims] An infrared detecting element for receiving infrared rays using an antenna, converting the received power into thermal energy with a bolometer, and detecting a temperature change as a resistance value change, comprising: a bolometer formed on a substrate; A pair of antennas connected to the bolometer, a pair of current supply leads for supplying a current to the bolometer, and a pair of voltage measurement leads for taking out a voltage generated at the bolometer end when supplying the current; An infrared detecting element comprising: 2. A pair of antennas connected to the bolometer and provided to face each other, a pair of current supply leads and a pair of voltages provided to face each other in a direction perpendicular to the pair of antennas. 2. The method according to claim 1, further comprising a measuring lead.
The infrared detecting element as described in the above.