JPH02181641A - Electrode plate for detecting water drop - Google Patents

Abstract

PURPOSE:To decrease the failure rate with age by disconnection, etc., and to improve working reliability by connecting many electrode rods disposed regularly through an insulated substrate on the rear surface of the substrate in such a manner that the rods belong to alternately different polarities and attaching a heater thereto. CONSTITUTION:A water drop W drastically lowers the insulation resistance of the adjacent electrode rods 20 with each other on the surface 10a of the insulated substrate 10, by which the sure detection of the water drops of rains and snow via wiring patterns 11 is executed. The stop of the fall can be detected from the restoration of the insulation resistance value between the electrode rods 20 on evaporation of the water drop W. Since the necessary heat for evaporation is transferred efficiently to the surface of the substrate 10 via the electrode rods 20 by the heater 30, the electric power consumption is minimized. Only the end faces of the rods 20 exist here and there on the surface of the substrate 10 and the durability against the physical force from the outside and after long-use is excellent. The possibility of the disconnection accident of the wiring patterns 11, etc., is minimal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a novel water droplet detection electrode plate for use as a basic component of rain sensors, snowfall sensors, and the like.

BACKGROUND OF THE INVENTION Many conventional rain sensors, snowfall sensors, and the like are equipped with an electrode plate for detecting water droplets caused by rain or snow by utilizing their electrical conductivity. Among these, a device that detects the sudden drop in insulation resistance between a pair of electrodes with different polarities when a water drop bridges the gap between a pair of electrodes, and detects the start of rain or snow, has a simple structure. Since the operating principle is clear, its practicality is extremely high.

In this case, the electrode plate consists of a pair of electrodes arranged in a continuous electrode pattern on almost the entire surface of an appropriately sized insulating substrate at a predetermined interval, and a heater attached to the back side. Rain or snow is detected by the water droplets bridging any point on the electrode, and when the rain or snow stops falling, the electrode surface is quickly dried with water.
It is possible to return to the state before activation.

Problems to be Solved by the Invention According to this prior art, since the pair of electrodes are continuous on the surface side of the insulating substrate, it is easy for the electrode pattern to break. The disadvantage was that most of the functions were lost. Furthermore, since an insulating substrate is interposed between the electrode and the heater, the thermal efficiency of the heater is low and the time required to dry the electrode plate becomes excessive, making it difficult to accurately detect when rain or snow has stopped falling. There tended to be cases where there was no such thing.

Therefore, an object of the present invention is to reduce the failure rate over time such as disconnection accidents by forming an electrode pattern like a collection of points separated by a predetermined interval, and also to reduce the failure rate over time such as disconnection accidents. It is an object of the present invention to provide an electrode plate for detecting water droplets, which can improve thermal efficiency and increase operational reliability by directly transmitting heater heat without any interference.

Means for Solving the Problems The structure of the present invention to achieve the object includes an insulating substrate, a large number of electrode rods regularly arranged on the insulating substrate and penetrating the insulating substrate, and It consists of a wiring pattern that is connected to alternately belong to different polarities and a heater attached to the back surface of an insulating substrate, and the gist is that the wiring pattern is provided on the back surface of the insulating substrate.

Note that the insulating substrate is made up of an upper layer substrate and a lower layer substrate, and the wiring pattern may be provided between both substrates.

According to this configuration, since the electrode rods pass through the insulating substrate, an electrode pattern is formed on the surface of the insulating substrate in which the end face portions of each electrode rod are regularly exposed. In addition, the electrode rod is
It has alternately different polarity depending on the wiring pattern. Therefore, when a water droplet adheres to bridge the end surfaces of two or more adjacent electrode rods, an electric circuit that can conduct electricity between the two or more electrode rods is constructed via the water droplet, and The insulation resistance value of changes rapidly. Therefore, by capturing this change, the presence of water droplets can be detected. Moreover, since the electrode rod penetrates the insulating substrate and is in contact with the heater on the back surface, the heater can efficiently heat the electrode rod.

It works as described above.

Example Examples will be described below with reference to the drawings.

The electrode plate for detecting water droplets (hereinafter simply referred to as the electrode plate) is
It consists of an insulating substrate 10, a large number of electrode rods 20, 20, and a heater 30 (FIG. 1).

The insulating substrate 10 is made of an insulating material formed into a plate shape with an appropriate thickness. As the insulating material, hard synthetic resin materials such as Bakelite and epoxy resin are suitable, but ceramics, silicone rubber, etc. can also be used. Further, the surface area S of the insulating substrate 10 is 10≦S≦100(c
n) degree is practical.

The insulating substrate 10 has a large number of electrode rods 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, etc. on almost the entire surface 10a of the insulating substrate 10, penetrating the board thickness.
... is installed. The electrode rods 20, 20... are regularly arranged and buried in the vertical and horizontal directions at predetermined intervals d, and the interval d is within the range where they can be wetted by one or several drops of water such as rain. As long as it can fit into the range, about 3
Approximately 7 mm to 7 mm is appropriate. However, if there is no problem even if there is a delay in the detection time of rain or the like, or if it is desired to cause a delay, the interval d may be made larger.

The length of each electrode rod 20 is set to correspond to the thickness of the insulating substrate 10, and therefore the front surface 10a and the back surface 1
0b, each end face portion of a large number of electrode rods 20, 20... is exposed (FIGS. 1 and 2).

When embedding the electrode rods 20, 20, etc., the electrode rods 20 have a diameter that fits watertightly into a small hole drilled in the insulating substrate 10 in advance.
．． 20... can be press-fitted. however,
The electrode rods 20, 20... can also be formed by pouring a low melting point metal such as solder into the small hole, or the insulating substrate 10 can be formed by solidifying a fluid material in a mold. In some cases, the electrode rods 20, 20, etc. may be embedded during molding. Furthermore, the electrode rod 2
0.20... can also be formed by the so-called through-hole plating technique. In this case, after through-hole plating, a metal rod of an appropriate diameter is driven into the small hole, or molten metal is poured into the small hole. Therefore, it is preferable to form the inside of the small hole solid.

Electrode rods 20, 20... are attached to the back surface 10b of the insulating substrate 10.
The wiring patterns 11 provided in the wiring patterns 11 are used to connect the wires so as to belong to alternately different polarities (FIG. 2).

The wiring pattern 11 is formed by forming a pair of copper foil patterns lla and lla belonging to mutually different polarities on the back surface 10b side of the insulating substrate 10 using a method similar to that used when making a printed circuit board.
was formed. - Pair of copper foil patterns lla, l
la are formed in parallel rows in the diagonal direction of the insulating substrate 10, and one end of each row is connected on opposite sides of the insulating substrate 10 every other row. Electrode rods 20 connected through such copper foil patterns lla, lla
．． 20... has a common polarity in the diagonal direction, but
In the vertical and horizontal directions, the polarities alternately belong to different polarities. Note that for the connection of the electrode rods 20, 20, etc., ordinary wires may be used instead of the copper foil patterns lla, lla.

The heater 30 is attached to the back surface 10b of the insulating substrate 10 (FIG. 3). The heater 30 is preferably a planar heater, but may be another type of heater. The heater 30 is
Although it is in close contact with the back surface 10b of the insulating substrate 10 so as to cover the wiring pattern 11 of the insulating substrate 10, the wiring pattern 11 and the electrode rods 20, 20, . . . are electrically insulated. It is assumed that Note that the heater 30 is preferably attached using an adhesive that is heat resistant and has excellent electrical insulation properties, but this may also be done by means such as screwing. Further, the heater 30 is constantly energized by combining an appropriate temperature controller, and the electrode rod 20.2
0... is used by heating it to a predetermined temperature.

Such an electrode plate can be used as an electrode plate for detecting water droplets in a rainfall sensor or a snowfall sensor.

That is, if a water droplet W falls onto the surface 10a of the insulating substrate 10 and spreads over two or more adjacent electrode rods 20, 20,..., these electrode rods 20, 20,...・
constitutes an electrical circuit that can conduct electricity via the water droplet W, and the insulation resistance value between the electrode rods 20, 20... decreases rapidly. Therefore, by detecting this via the wiring pattern 11, the presence of water droplets W due to rain or snow can be reliably detected.

When the rain or snow stops falling, the water droplets W evaporate and the electrode rod 20.20
This can be determined by the insulation resistance value between returning to its original value. At this time, the heater 30 supplies the vaporization heat necessary for the water droplet W to evaporate, but the heat from the heater 30 is transferred to the electrode rods 20 and 20 passing through the insulating substrate 10.
Since the power is efficiently transmitted to the surface 10a of the insulating substrate 10 through the insulating substrate 10, the power consumption of the heater 30 can be minimized even when the insulating substrate 10 has a large thickness. Can be done.

In addition, each electrode rod 20 is not continuous on the surface 10a side of the insulating substrate 10, and its end face portions are only scattered. It has excellent strength and durability over time, and there is extremely little risk of disconnection of the wiring pattern 11.

Another embodiment The insulating substrate 10 may have a two-layer structure consisting of an upper layer substrate 10C and a lower layer substrate 10d (FIG. 4). Electrode rods 20, 20... are upper layer substrate 10C1 lower layer substrate 10
d, and the wiring pattern 11 is provided so as to be sandwiched between the upper layer substrate 10c and the lower layer substrate 10d.

Since the wiring pattern 11 can be protected from above and below, reliability against disconnection accidents and the like can be further improved, and the heater 30 can be attached more easily.

As described in detail, according to the present invention, a large number of electrode rods are regularly arranged on an insulating substrate, penetrating through the thickness of the insulating substrate, and the wiring for the electrode rods is arranged according to the wiring pattern of the insulating substrate. By connecting the adjacent electrode rods so that they belong to different polarities alternately and attaching a heater to the back surface of the insulating substrate, the electrode pattern is created such that the end surfaces of the electrode rods are regularly scattered on the surface of the insulating substrate. This has the excellent effect of effectively eliminating disconnection accidents and greatly reducing the failure rate over time.

In addition, heat from the heater can be transferred to the surface of the insulating substrate via the electrode rod penetrating the insulating substrate.
Another advantageous effect is that the thermal efficiency of the heater can be increased and the overall operational reliability can be significantly improved.

[Brief explanation of the drawing]

Figures 1 to 3 show examples, with Figure 1 being a partially cutaway overall perspective view, Figure 2 being an explanatory plan view of the wiring pattern, and Figure 3 being an explanatory plan view of the wiring pattern.
The figure is an enlarged sectional explanatory view of the main part. FIG. 4 is a diagram corresponding to FIG. 3 showing another embodiment. 10...Insulating substrate 10b...Back surface 10C...Upper layer substrate 10d...Lower layer substrate 11...Wiring pattern 20...Electrode rod 30...Heater

Claims (1)

[Scope of Claims] 1) An insulating substrate, a large number of electrode rods regularly arranged on the insulating substrate and penetrating the insulating substrate, and wiring connected so that the electrode rods have alternately different polarities. An electrode plate for detecting water droplets, comprising a pattern and a heater attached to the back surface of the insulating substrate, the wiring pattern being provided on the back surface of the insulating substrate. 2) The insulating substrate consists of an upper layer substrate and a lower layer substrate,
2. The electrode plate for detecting water droplets according to claim 1, wherein the wiring pattern is provided between the upper layer substrate and the lower layer substrate.