JPS60191051A - Pyroelectric type infrared ray decting element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pyroelectric infrared detection element suitable for detecting the movement of a human body, the presence or absence of an object, etc.

[Technical background of the invention and its problems]

With the development of so-called microelectronics, for example, infrared detection elements (infrared sensors) are increasingly being applied to detect the presence or absence or movement of a human body, the presence or absence or movement of an object, or non-contact temperature measurement.

By the way, the type of infrared detection element mentioned above is a quantum type that uses semiconductor photoconduction and photovoltaic force.

For example, Hg Cd Te −? Those whose main body is PbS are known. Although this quantum infrared detection element has good sensitivity and excellent response, it must be cooled to an extremely low temperature before use, making it difficult to handle, and its sensitivity in the infrared region is also wavelength dependent. Therefore, the application is limited and there are problems in practical use.

On the other hand, attempts have been made to develop so-called pyroelectric infrared detection elements that utilize the pyroelectric effect of lead zirconate titanate (PbZr Tl 03) or lead titanate (PbTi03).

However, these Pb Zr 'I'l 03 and PbTl0
The sintered body (ceramics) that forms the main body of a detection element such as No. 3 has advantages such as not requiring particular cooling during use and no wavelength dependence, but has the disadvantage of being inferior in terms of performance such as sensitivity. That is, in an infrared detection element using the pyroelectric effect, its performance is greatly influenced by the evaluation index Fv for the voltage generated by the pyroelectric effect.

Here, the evaluation index ii”v is the pyroelectric coefficient P(C//crIL
2°C), specific heat at constant volume Cv (J/'CrIL3°C), and relative dielectric constant 6.

In terms of performance as a sensor, it is desired that the pyroelectric material forming the main body of the infrared detection element has a large pyroelectric coefficient P and a small Hazumi specific heat CV and dielectric constant ε.

However, in the case of Pb Zr 'r103, the specific heat at constant volume C
v-2,42J/CrrL3℃, but dielectric constant g=3
80 to 1700, and in the case of Pb'l"i03, the specific heat at constant volume Cv = 3.11J7cm3' (),
Pyroelectric coefficient % = 1.8 x 10-8C/rx2°C
Evaluation index Fy = 0.3 x 10-'QC-am
/J, which causes performance problems as described above. Especially P
When polarizing the bTs03 pyroelectric material to cause spontaneous polarization, it is necessary to apply an electric field of 601 (■ axis or higher) at a high temperature of 200°0, and this polarization process also poses a practical problem. .

[Purpose of the invention]

The present invention addresses the above-mentioned circumstances and provides a pyroelectric infrared detecting element which is highly sensitive and highly usable for horses, and which can be operated at room temperature.

[Key points of the invention]

The present invention uses one or more of the general formula % (where fvle = Ba, Sr, Ca).

X = number from 0.05 to 0.35, y = 0.01 to 0.
10) of the composite perovskite t1°4 structure.

A pyroelectric infrared detecting element characterized in that its main body is a sintered body containing at least one of MnO, NiO, I+'e2'03 added in an amount of 0.01 to 18%. .

Therefore, the present invention provides a composite perovskite structure represented by the above general formula with a predetermined amount of NiQ, P, 400°F.
This is based on the knowledge that a sintered body containing e203 or the like exhibits f'-favorable pyroelectricity and has excellent practical performance as an infrared detection element (sensor).

[Practice of the invention 4i1J] First, (Pb+-x Cax) C(COt/2Wl/2
) 0.04 'I”o, 96 ) 03 +0.3.
7ff, Fi'r%~InO10.4foldhce%NiO
PbO so that

CaCO3, Ti (J2. coo, wo3. Mn
A predetermined amount of -5 tons of CO3, l'+5 and NiO were each weighed out and wet-mixed using an alumina bot mill. After calcining these mixtures at 900'0 for 2 hours, they were pulverized with an alumina bond mill to obtain raw material powder.
I did 4'J. Next, these raw material powders are pressed into a sheet, and punched from this sheet with a diameter of 20 mm using a force of 1 mm.
mz discs were obtained, and the discs were placed in a magnesia container and fired at 1100 to 1180"O for 0.5 to 4 hours to obtain thin discs with a thickness of 1 = @ 4 μm and a diameter of 20 mm. A pair of electrodes was formed by adhering to each other.The polarity was determined by immersing it in silicone oil for 100 minutes and then heating it for +40 to 50K.
Apply a pressure of V/CnL to I, polarize for 5 minutes, age at 100°C for 24 hours, and then cut into 3 x a mz pieces with a precision cutter to form a pyroelectric infrared detection element (sensor). were obtained respectively.

Regarding each pyroelectric infrared detection element obtained as described above, the composition ratio of the pyroelectric material (Pb to C
When we measured the relationship between a If conversion amount
It was as shown in the figure. In Figure 1, curve (1) represents the pyroelectric coefficient P and curve (2) represents the relative permittivity ε and represents the two curves m* (3
) indicate the evaluation index 1·v, respectively, and for comparison, the pyroelectric coefficient P of lead titanate (Pb Tr 03 ) is marked ◎,
The evaluation index FV is indicated with a mark.

As is clear from Fig. 1, the value of X, that is, Pb due to Ca
The pyroelectric coefficient P shows a high value when the substitution ratio of lower than 380 in case. Furthermore, the evaluation index FV also has a value of X of 0.
However, as shown in the Mog2 diagram, even a single Curie point had a value of 200'0 or more, and no practical inconvenience was observed as an infrared detecting element.

On the other hand, when the pyroelectric infrared detection element according to the present invention was evaluated from a practical standpoint, the following σ was "1".
Regarding the 1g type infrared detection element, which is made by removing a part of the metal handle on one side of the 3x3im piece made by two people and making the element surface exposed. Pressure sensitivity I
(v and ratio (·, Flow performance were measured respectively.

Both lead titanate (Pbi”i 0
3) The performance was 20 to 100% superior to that of the infrared detecting element having the main body.

Here, E is also negative iji, -(>r ke 4 strokes, i:, +
(The pressure generated at '' is applied to the load resistance (dllO ~ 121 (
The value obtained by impedance conversion with the source follower of F J, Th '11' (% field effect transistor) of Ω,
It is expressed as a ratio to the power value of incident infrared rays.

In FIG. 3, (e) shows a power supply terminal, (f) shows an output terminal, and (g) shows a ground. The smoke ratio detection ability (■) is the infrared detection element (al's miscellaneous tf output "Ne'j" and the pressure sensitivity I
This value is calculated using the following formula, where Q b and the surface area A of the infrared detection system (a) are expressed as %.

As described above, the pyroelectric infrared detection element according to the present invention has a voltage sensitivity of 1 (V) which can be viewed directly as an infrared sensor in practical use.

Ratio detection ability■ Not only is it excellent such as N, but also 9 For example, 9
100 at 5% relative humidity and 40°C (with almost no deterioration in characteristics even after continuous operation for 1 hour,
It was also confirmed that the X (fj) of the 11th eye of the tiger as an infrared detection element was sufficiently blue over a long period of time.

In the case of the above, the main component of the main body of the pyroelectric infrared detection element is a perovskite (PbC).
a) [I (Co I/2 W)/2)'I”l
] In the 03 system, an example was shown in which the ratio of Ti and (COl, /2W, /2) was kept constant and the ratio of Pb and CaO was changed, but it is also possible to use Ba and Sr instead of CaO.

Also, the ratio of '1゛1 and (Cot/2 Wl/2) is 0.
Almost the same performance was obtained when the value was changed to a range of 0.01 to 0.10.

In the sintering process, Pb(Co□/2 Wl/2)03, which is a part of the general formula % formula %, which constitutes the main body and y part of the pyroelectric infrared detecting element according to the present invention, is The composition ratio, that is, the value of y in the above general formula, must be selected within the range of 0.01 to 0.10. If the knock-out is less than 0.01, there will be no effect such as lowering the firing temperature mentioned above, and if it exceeds 0.10, the dielectric constant will become too large, and from a practical point of view, the evaluation index for voltage will decrease, and the infrared The performance as a sensor is good, and the above (J") + - x N1ex) [(COI/
At least one persimmon oxide selected from the group of Lin0.NiO and Fe203 added to 2Wl/2)y''1-y)03 was added to the resulting pyroelectric sintered body during the separation treatment. However, this ('fQ addition 14 is not 001% by weight)
However, even if it exceeds 2%, the pyroelectricity will drop sharply and the sinterability and polarization properties will be impaired. It is necessary to select within the range of sleeve percentage.

〔Effect of the invention〕

As described above, according to the present invention, the general formula (PJ-8Mex
) [(CO1/2X'+/2)y'l"t-y:]0
K N4n with a composite perovskite structure shown in 3
The main body of the infrared detecting element is a ceramic sintered body containing at least one selected from O, Neo, and Fe203 in an amount of 0.01 to 2% by weight. Therefore, the ceramic sintered body is in the form of a pyroelectric material having a large pyroelectric coefficient.

It has a low dielectric constant and has excellent characteristics as an infrared detection element.

In other words, the evaluation index F■ required for this type of infrared detection element
It is characterized by a large pyroelectric coefficient P(C/crn2-(3)) that greatly contributes to the , and a small relative dielectric constant ε.

However, from a practical point of view, the voltage sensitivity Ity as a response to infrared irradiation is high, while the sound output is low, so it exhibits high specific detection ability. In other words, it has high sensitivity, high reliability, and 113: can be easily detected.Furthermore, the aging characteristics are also good, and the desired infrared detection function is retained and exhibited over a long period of time > uJ.Thus, the infrared detection element according to the present invention is easy to sinter and can be easily polarized. 100°
A temperature of about 40 to 5 QkV/cm and a polarization pressure of 1 is sufficient.
Coupled with the fact that it is easy to manufacture, it can be said that it is a pyroelectric infrared detection element suitable for practical use.

[Brief explanation of the drawing]

Figure 1 is a curve diagram showing the relationship between the pyroelectric coefficient, dielectric constant, evaluation index, and composition for one pulse of the pyroelectric infrared detecting element according to the present invention. A curve showing the relationship between the composition and the Curie intensity for an example of the pyroelectric infrared detecting element according to the invention: (al... Infrared detection element, (Ill... Infrared 4-pin. (Cl... High resistance load, (e)... 1h source terminal. (fl... Output terminal, (g)...・Earth Agent Ben J
Kensuke Chika (and 1 other person) Fig. 1 Ca ffl x (mol) −

Claims (1)

[Claims] General formula %) (In the formula, Me is at least one element selected from Ba, 8r, and Ca, X is a numerical value of 0.05 to 0.35, and y is 0. 01 to 0.10) MnO has a composite perovskite structure. A sintered body K formed by adding and blending at least one selected from Nip and Fe2O3 in an IT ratio of 0.01 to 2%. A pyroelectric infrared detection element characterized by comprising a pair of electrodes.