JPS6180038A - Organic polymer humidity sensor - Google Patents

Abstract

PURPOSE:To prevent the generation of a crack by the buffering action of a protective film, by increasing the thickness of the protective film provided to the upper end surface of a substrate and in the vicinity thereof. CONSTITUTION:In usual work, a sensor main body 1 coated with a silicone resin by immersion is attracted and fixed to the part of the rubber magnet 8 of a drying jig 7 through a lead wire and allowed to stand for about 16min at room temp. in an inverted state. Next, said sensor main body is set up and dried at 110 deg.C for 2hr. In order to increase the film thickness at the end part (a) of the sensor main body 1, standing at room temp. in an inverted state is extended to 1hr and, after curing advanced to a certain degree, said main body is reversed to be subjected to final drying at 110 deg.C for 2hr. As mentioned above, by extending a natural standing time in an inverted state, a protective film 6 can be applied to the end part 1a in a sufficient thickness. By this method, the hydroscopic speed at the leading end part becomes slow and the elongation of a humidity-sensitive film becomes small and the crack generated at the leading end part is reduced to a large extent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an organic polymer humidity sensor used in room air conditioners and other home appliances.

[Background of the invention]

Conventional humidity sensors, as described in JP-A No. 50-20781, are made by coating a glass substrate with a moisture-sensitive resin made by reacting an organic polymer with chlorine atoms with a polyamide resin, and then applying a protective coating on top of the moisture-sensitive resin. The company claims that by coating the product with a membrane, the effects of a contaminated atmosphere containing dust and sulfur dioxide gas can be significantly reduced. However, there is no mention of the sensor's long-term stability or the origin of cracks.

[Purpose of the invention]

The purpose of the present invention is to prevent cracks from occurring in the humidity sensitive part of a humidity sensor by adjusting the working conditions to prevent the film from forming on the upper edge of the substrate, which tends to be thinner in the normal protective film application process. By setting the thickness, the film thickness can be made thicker, and the occurrence of cracks can be prevented by its buffering effect.

[Summary of the invention]

That is, conventionally, after a silicone resin protective film is immersed in a resin solution to obtain a uniform thickness on a substrate, the substrate is turned upside down while the silicone resin protective film is still fluid to spread it over the entire surface.

However, with this, the end surface becomes thin (so, in order to correct this, first place the upper end face down, semi-dry it in this state, then change the orientation and fully heat cure it to make sure that the end part is fully covered with resin. I tried to do so.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4. Reference numeral 1 denotes the humidity sensor body, which is completed by coating a ceramic substrate 2 with electrodes made of gold and lead glass by firing, applying a moisture-sensitive film 5, and then forming a protective film 6 of silicone resin. The silicone resin of the protective film uses an additive two-component type.
After mixing in equal proportions, strain for immediate dip application.

In normal operation, the sensor body 1 coated with silicone resin is suctioned and fixed to the rubber magnet 8 of the drying jig 7, and is left upside down at room temperature for about 15 minutes. Next, it is raised and dried at 110° C. for 2 hours.

In this improved method to thicken the film at the edges, we left it upside down at room temperature for 1 hour, and after it had cured to some extent, we turned it over and put it in the main drying stage at 110℃ for 2 hours. Make it.

〔Effect of the invention〕

According to the present invention, since the time of natural standing in an inverted state is extended, it is now possible to apply a sufficiently thick protective film, unlike the conventional protective film, which tends to become thinner at the edges. As a result, the rate of moisture absorption at the tip becomes slow (and the elongation of the moisture-sensitive film becomes small), and the cracks that often occur at the tip of conventional sensors are significantly reduced by the present invention, contributing to improved sensor reliability. The effect is great.

[Brief explanation of the drawing]

FIG. 1 is a front view of the humidity sensor, FIG. 2 is a side sectional view of FIG. 1, and FIG. 3 is a side view of the humidity sensor manufactured according to the present invention. FIG. 4 is an external view of the protective film drying jig. 1... Humidity sensor body, 2... Ceramic substrate, 3
... (Rhibson shaped electrode, 4... Lead wire, 5... Moisture sensitive membrane, 6... Protective film, 7... Drying jig, 8... Rubber magnet.

Claims (2)

[Claims] 1. In a humidity sensor in which the top surface of a comb-shaped electrode formed on a ceramic substrate is covered with a moisture-sensitive film made of an organic polymer and a protective film made of silicone resin, we have developed a technology that increases the thickness of the protective film on the top edge of the substrate and its vicinity. Characteristic organic polymer humidity sensor. 2. 2. The organic polymer humidity sensor according to claim 1, wherein the protective film is immersed in silicone resin, left to semi-dry at room temperature with the upper end of the substrate facing down, and then turned over and heated to dry.