JPS5832303A - Humidity sensitive dielectric loss 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] The present invention relates to a moisture-sensitive dielectric loss body element.

A moisture-sensitive dielectric loss element is an element that is sensitive to humidity and whose dielectric loss (dielectric loss tangent) changes depending on the humidity, and is used as a humidity measurement element or a humidity adjustment sensor. As is well known, Fe2o3, Al2O3, C
r2o3. Metal oxides such as N1203 have excellent water absorption properties, and therefore, moisture-sensitive resistor elements are manufactured using such properties.

However, moisture-sensitive resistor elements using the above-mentioned metal oxides generally have high resistance, and even if there is a change in resistance due to moisture adsorption/desorption, it is difficult to electrically detect this with high accuracy. It is something. That is, this type of element is limited to applications in high humidity regions, such as detection of dew point, for example.

In order to make an element with a resistance value that is easy to measure, alkali metal-based substances, such as
Attempts have been made to add and mix compounds such as Na and Li. However, in this method, although the absolute value of resistance decreases, under high humidity conditions, alkali metal compounds are eluted and the moisture-sensitive resistance characteristics change. For these reasons, it is difficult to actually use it. Furthermore, these elements obtain moisture-sensitive characteristics through ionic conduction of physically adsorbed water.

For example, the moisture-sensitive resistance characteristics change simply by exposure to an atmosphere containing low-concentration components that are easily ionized.

The present invention has been able to solve these problems, and provides a completely new moisture-sensitive dielectric loss element, unlike conventional moisture-sensitive resistors.

That is, the element according to the present invention has three ABo components (where AB is KTa, PbHf, LiTa, Li
Nb.

CaTi, PbZr, NaNb, KNb, P
(At least one type selected from bTi) or a porcelain or film containing it as a main component with at least one pair of electrodes, and a PbxO3 component (where X is (Mq)"X), (Cd3AW3) ), (
Co, w, ), (S c, Nb,).

(F epgNbh) t (I n, ANb34)
, (YbHNb34).

(H033N b>ρt (F e H” a>ρ,
(S C42T a3.,, ).

(Lu, Nb5A), (Lu, Ta,), (Mq
,Nb,).

(Zn, Nb%), (Co, Nb, B), (N
i, Nb, ρ.

(Mq3A""X) + (CoM"aX
) t (N'3' T-) t (Fe%%), (M
It is an element in which at least one pair of electrodes is provided on at least one kind selected from the following (n%W%) or a metal oxide-based porcelain or film containing it as a main component, and the distance between the electrodes changes depending on the humidity. We discovered a phenomenon in which the dielectric loss (dielectric loss tangent) of

The present invention is based on the discovery of such a phenomenon. Furthermore, by selecting the composition, it is possible to obtain an element that exhibits high sensitivity from low humidity to high humidity. The relative humidity-dielectric voltage contact characteristic is approximately logarithmically linear from low humidity to high humidity.

More specifically, the composition according to the present invention is a type of dielectric, and by selecting its composition, it is possible to produce an element whose dielectric loss tangent value changes greatly due to changes in humidity.

Furthermore, the element of the present invention is a compound having a perovskite crystal structure, and its temperature coefficient of dielectric loss tangent is also small. By applying an alternating current voltage to this element and detecting the phase difference between the current and voltage, it is possible to easily adjust the relative humidity to
Humidity can be detected in the entire humidity range of %.

Furthermore, its humidity response is also fast.

The composition according to the present invention can be easily manufactured using a thin film manufacturing technique, which is a conventional porcelain manufacturing technique.

Furthermore, since this is a so-called metal oxide, its surface condition does not change even if it is left in the atmosphere for a long period of time.

In the present invention, the reason why the composition is specified as described above is as follows.
This is because it is a compound with a perovskite crystal structure, and changes in dielectric loss tangent are uniquely determined by changes in humidity. Furthermore, this element can obtain high sensitivity from a low humidity region to a high humidity region.

Six embodiments of the moisture-sensitive dielectric loss body element according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a typical structure of an embodiment of a moisture-sensitive dielectric loss body element according to the present invention. FIG. 1A shows a bulk type element, and FIG. 1B shows a model element.

These elements have the same essential function whether they are made of porcelain or ceramic. In Figure A, 1 is a moisture-sensitive dielectric loss body made of ceramic, 2.3 is an electrode, and 4 and 6 are lead wires. In Figure B, 6 is a film-like moisture-sensitive dielectric loss body, 7 is its support substrate, 8.9 is a comb-shaped electrode, and 10.11
is the lead wire.

First, a moisture-sensitive dielectric loss body element denoted by ABO3 will be described.

As starting fee, l0. , T 102 are wet mixed into a dry powder. Next, add this powder raw material to 4 +w
m x 4 w x 0, 26 tm (molding pressure 760 kg/cnf) L, my, and fired at 1160° C. for 2 hours to produce a moisture-sensitive dielectric loss body 101 made of P bT 10s porcelain. Furthermore, RuO is used as the moisture-sensitive dielectric loss material.
A pair of electrodes was formed by applying a type 2 electrode paste and baking it at a temperature of 800°C. Note that the electrodes are PT-based, Aq-based,
Au-based materials are also suitable. In addition, other compositions KT aO3, PbHfO3, LiT ao3.
L 1NbO3+ CaT iO3゜Pb Z rO
a, NaNbO5, linseed. , and pbxo3, the other m-formed pb(Mq3AW3A)o3. Pb
(Cd3AW%)03°Pb (Co%W,)03.
Pb (S c3ANb3003゜P b (F ”3
(Nb%) 03. P b (I n3ANb%)
oa rPb(Yb3ANb3A)03. Pb(Ho
y6Nbh)03゜P b (F e HT a M
) 03. P b (S c3AT a3A) 03
.

Pb(Lu3ANb+r)Os, Pb(Lu3ATa3
A) 03°P b (Z n3AN bH) 03,
P b (C03AN b X ) 03°P b
(N i XN bX ) 03. P b (M g
3AT a B ) 03°P b (C03AT a
X) 03. P b (N 1 y, T a
X ) oa rP b (F e XWM ) Oa
, P b (M n

Then, a platinum lead wire was baked at 800° C. using Ruo2 paste on the electrode portion of the moisture-sensitive dielectric loss body obtained as described above to obtain a humidity-sensitive dielectric loss body element.

Furthermore, when the moisture-sensitive dielectric loss element is a film type, a film of the moisture-sensitive dielectric loss element can be formed by sputtering, vapor deposition, screen printing, or the like to similarly obtain elements of various compositions.

FIG. 2 shows the relative humidity-dielectric loss (dielectric loss tangent, expressed as a ratio to 0% relative humidity) sensitivity characteristic of the PbTio3 moisture-sensitive dielectric loss element. The characteristics for devices with other compositions are shown in the table below.

From Figure 2 and the table above, experiments have shown that the element of the present invention has a perovskite structure mainly composed of the above-mentioned compositions, and that the dielectric loss tangent changes greatly in response to changes in humidity. It was revealed by

Furthermore, it was confirmed that a humidity-sensitive dielectric loss element composed of a main component containing at least one of the above-mentioned compositions was extremely stable, with a change in dielectric loss tangent characteristic of 40 to 40 relative humidity within a few inches. Furthermore, regarding the humidity response, the response speed is within several seconds at relative humidity of 0 to 100%, which is extremely fast.

The element of the present invention differs from conventional ion-conducting types that exhibit moisture-sensitive resistance characteristics, and the change in dielectric loss tangent caused by the dielectric loss due to the moisture itself adsorbed on the element, that is, dielectric dispersion, is extremely stable, and moreover, Stable humidity detection can be obtained for organic gases, acidic gases, etc.

Furthermore, in the present invention, as various additives, PbHf
0L, LiTaO3, LiNbO3, BaZrO3
, CaZrO2゜SrZrO3, MgZrO3, PbZ
rO3, NaNbO3, KNbO3゜PbT IOs
By adding one or more types of tMgCr204 or the like (excluding those of the same type as the main component), it is possible to obtain a highly sensitive moisture-sensitive dielectric loss body element with good responsiveness and extremely little deterioration of characteristics.

As explained above, the moisture-sensitive dielectric loss element according to the present invention is a completely new moisture-sensitive element having humidity-dielectric loss tangent characteristics, and is capable of high stability and high-precision detection, and is useful in industry. To provide a moisture-sensitive dielectric loss body element of great value.

[Brief explanation of drawings]

FIGS. 1A and 1B are diagrams each showing a typical structure of an embodiment of an element according to the present invention, and FIG. 2 is a characteristic diagram showing a typical example of its humidity-dielectric voltage contact characteristics. 1.6...-Moisture-sensitive dielectric loss body, 2,3,8.9.
·····electrode. 111Figure 12 Figure σ 20 41 60 110
100 Relative Relative Friends (%)

Claims (1)

[Claims] (1) ABO3 components (AB is KTa,
PbHf ′LiTa LiNb CaTi Pb
1. A moisture-sensitive dielectric loss body element comprising at least one electrode selected from Zr, NaNb, KNb, and PbTi, or a ceramic or film containing the same as a main component, and provided with at least one pair of electrodes. t (I n , ANbH) t (Yb3ANbM
) t (HoM' bM ) t(F @54 Ta
,) l (5ChTab) t (Lu, Nb,)
t(Fe%W%), (Mn%Wh)) or a metal oxide-based porcelain or film containing it as a main component is provided with at least one pair of electrodes. Features a moisture-sensitive dielectric loss element.