JP4793769B2 - Method for improving light transmission of plate, windshield device and rearview mirror device using this method - Google Patents

Description

  In the present invention, plasma is generated by an electrode disposed on the surface or inside of a plate such as glass or film, and the shape or movement of droplets adhering to the surface or the hydrophilicity of the surface of the plate is controlled. In addition, the present invention relates to a method for improving light transmission or light reflection of a plate such as a film, and a windshield device and a rearview mirror device for a vehicle equipped with a wiper using the method.

  Windshields or rearview mirrors used in vehicles such as automobiles, railways, and aircraft are made of silicate glass, acrylic, etc., but are indispensable for passengers to secure external visibility and drive operations. .

  2. Description of the Related Art Conventionally, an electric wiper is provided on a windshield windshield and a side rearview mirror of an automobile in order to secure an external field of view in rainy weather. The structure is well known, but the arm with linear rubber is moved left and right by a motor and a link mechanism, and the raindrops on the glass surface are mechanically collected and smoothed by the rubber, and the surface of the raindrops is smoothed. By reducing the contact angle and eliminating light scattering, the light transmission or light reflectivity is enhanced and the external field of view is improved.

  Here, an angle formed by the glass surface and the surface of the raindrop is called a contact angle. The smaller the contact angle, the closer the raindrop shape is to a flat surface and the more hydrophilic. Conversely, the larger the contact angle, the closer the raindrop shape is to a spherical shape, and the better the water repellency.

  However, such mechanical wipers are widely used in automobiles, railways, airplanes, etc. and have high performance, but they are mechanically movable during vehicle operation, which hinders the driver's driving operation, It is desirable to eliminate it if possible. To date, however, no method or apparatus has been invented that surpasses the performance of this mechanical wiper.

  On the other hand, for example, an additive containing a chemical having water repellency such as trialkoxysilane is uniformly applied to the glass surface in advance to improve the water repellency of the glass and increase the contact angle of raindrops on the glass surface. There are known methods and products for removing droplets by scattering them to the left and right by the drag of the wind accompanying the progress of the vehicle.

  However, this method is effective only when the vehicle is moving at a high speed of a certain level or more (for example, it is effective when traveling on a highway in a car) and has little effect when stationary. Also, the durability against rain is relatively short in a few days, and it is not a complete replacement for mechanical wipers. In addition, many of the water repellents used contain harmful components, and large amounts are not preferred from the viewpoint of environmental conservation.

  Furthermore, by applying atmospheric pressure low-temperature plasma generated by corona discharge to the glass surface and immediately applying the surface with a water-repellent trialkoxysilane, the durability of the water-repellent agent against water droplets can be improved. Non-patent document 1 and, for example, patent document 1 report it.

Non-Patent Document 1 describes that the glass surface can be hydrophilized by applying plasma to the glass surface. By making it hydrophilic, the raindrops on the surface of the glass are smoothed, the contact angle of the raindrops is reduced, and light scattering can be eliminated, thereby improving the light transmission. Further, when the glass is replaced with the glass on the surface constituting the mirror, the light reflectivity can be improved. However, it has been reported that the effect of improving the contact angle disappears in a few hours to a few days if left unattended, and disappears in a shorter time when it rains.

Therefore, in order to ensure continuous visibility or hydrophilicity, it is necessary to periodically apply plasma to the glass. However, in the atmospheric pressure plasma application apparatus and method in which a high voltage with a frequency of 60 Hz reported in Non-Patent Document 1 is applied between flat plate electrodes to sandwich the glass, the plasma reactor itself enters a small container, and the glass and the electrode are integrated. It was difficult to install on windshields and rearview mirrors of vehicles.
Japanese Patent Publication No. 8-337654 T.A. Yamamoto, M .; Okbo, N .; Imai and Y.M. By Mori, “Improvement on Hydrophilic and Hydrophobic Properties of Glass Surface Treated by Non-Plasma Induced by Silence, Ps.

  When liquid droplets are present on the surface of a plate such as glass, mirror, or film, the optical transparency or light reflectivity of the plate such as glass, mirror, or film is improved without using a mechanical wiper to ensure external visibility. And a windshield device provided with a vehicle wiper based on the method and a rearview mirror device provided with the wiper.

The following means [1] to [ 3 ] according to claims 1 to 3 are used.
[1] Plasma is generated by electrodes fixed on or in contact with the surface of the plate , and the shape or movement of droplets existing on the surface or the hydrophilicity of the surface of the plate is controlled, so that the light of the plate A method for improving permeability is used.
[ 2 ] A windshield device for a vehicle provided with a wiper using the method of [1], wherein the plate is glass.
[ 3 ] A vehicle rearview mirror device provided with a wiper using the method of [ 1 ], wherein the plate is glass on the surface constituting the mirror.

  According to the present invention, by generating plasma on the surface of a plate such as glass or mirror or film, and controlling the shape or movement of droplets existing on the surface or the hydrophilicity of the plate surface, it is light transmissive or light reflective. The windshield device provided with the wiper of the vehicle which does not have a mechanical movable part, and the rearview mirror device provided with the wiper can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not construed as being limited to these embodiments, and the knowledge of the inventor can be used without departing from the scope of the present invention. Various changes, modifications and improvements can be made based on this.

  FIG. 1 is a perspective view showing an example of the embodiment. A flat plate or net-like back electrode 2 is attached to the back surface of the glass 1, and the shape of the surface electrode 3 is a thin parallel straight line. The material of the glass 1 is not limited as long as it is insulative, and may be a film such as a polymer. The material of the electrode is not specified, but a transparent conductor such as ITO (Indium Tin Oxide, indium oxide added with tin oxide) or conductive plastic is desirable.

When the droplet 5 drops on and adheres to such glass during rainy weather and the visibility is obstructed (FIG. 1 (a)), the high voltage power supply 4 is switched on between the front and back electrodes and applied to the surface. Low temperature plasma such as creeping discharge plasma is generated around the electrode 3. As shown in FIG. 1B, most of the glass surface is hydrophilized, and the water droplet becomes a flat region 6 so that light scattering is suppressed and light permeability to raindrops is maintained. Moreover, when the glass 1 is the glass of the surface which comprises a mirror , light reflectivity is maintained. Even after the plasma is stopped, this hydrophilicity is maintained for a considerable time. If the hydrophilicity is lost, the plasma may be applied again.

  The type of the high-voltage power supply 4 applied between the electrodes is not particularly limited, but AC, DC, and pulse voltage are preferable. The optimum voltage value also depends on the thickness of the glass plate, but a pulse high voltage of about 12 kV peak is exemplified in the case of 2 mm.

  The front view of the glass with an electrode which is another embodiment in FIG. 2 is shown. A flat plate or net-like back electrode 2 is pasted on the back surface of the glass 1, and the shape of the surface electrode 3 is a thin U-shape.

  The front view of the glass with an electrode which is another embodiment in FIG. 3 is shown. A flat plate or net-like back electrode 2 is attached to the back surface of the glass 1, and the shape of the surface electrode 3 is a large number of thin rods.

  The front view of the glass with an electrode which is another embodiment in FIG. 4 is shown. A flat plate or net-like back electrode 2 is attached to the back surface of the glass 1, and the shape of the surface electrode 3 is a continuous straight line as shown in the figure.

  The front view of the glass with an electrode which is another embodiment in FIG. 5 is shown. A flat plate or net-like back electrode 2 is pasted on the back surface of the glass, and the surface electrode 3 has a large number of thin needle electrodes 9.

  The front view of the glass with an electrode which is another embodiment in FIG. 6 is shown. A flat plate or net-like back electrode 2 is pasted on the back surface of the glass, and the shape of the surface electrode 3 is a thin one-way net electrode.

  As described above, in the electrode arrangements shown in FIGS. 1 to 6, there are optimum voltage values and intervals suitable for each, and the design suitable for the situation should be made. Further, at least one of the pair of electrodes may be positioned inside the glass.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples, and various plasmas are used for various shapes and types of plates such as glass or mirrors or films. It can be implemented using a power source.

  A silicate glass with electrodes having dimensions as shown in FIG. 7 (simulating one pattern of the electrode arrangement in FIG. 3; the dimensions are shown in FIG. 7 in mm units, hereinafter referred to as A) was prepared.

  As another example, the electrode-attached polyester film-silicate glass composite material having dimensions as shown in FIG. 8 (the polyester film 7 is pasted on the surface of the glass and imitating one pattern of the electrode arrangement in FIG. 2). It is shown in FIG. 8 in the unit of mm.

  The surface of the A and B electrodes was lightly polished with a polishing agent and washed with ethanol to remove the oil on the surface after the trial production, and then the test was started. A high voltage was applied between the A and B electrodes, and uniform creeping discharge plasma was generated in the vicinity of the electrodes. The contact angle of water droplets (diameter 2 mm) before and after generation was measured with a contact angle meter (Kyowa Interface Science Co., Ltd., CA-DT type).

  A pulse high voltage having a peak voltage of about 12 kV, 305 Hz, and a rise time of about 60 μs was applied between the A and B electrodes by a positive pulse high voltage power supply 8. The waveforms of voltage V and current I are shown in FIGS. This waveform was measured using an Yokogawa oscilloscope (DL1740-1GS / s), a Pearson current probe (Model 2878), and a Sony Tektronix voltage probe (P6015A). A pulsed current waveform I peculiar to pulse creeping discharge is observed.

Table 1 shows the results. For A and B, the contact angles at positions (1), (2), and (3) were measured for 1 day before plasma application, immediately after application for 1 minute, immediately after application for 3 minutes, and after application for 1 day. did. Note that A is not measured at position (1).

  As can be seen from Table 1, in A, the contact angle is 7 ° or less in the vicinity of the electrode (2) immediately after application for 1 minute, and sufficient hydrophilicity is obtained. In addition, in (3), since it is away from the electrode, the contact angle is hardly lowered. Further, the decrease rate of the contact angle is smaller on the surface of B (polyester) than on the surface of A (glass), but in B, the contact angle is 25 ° or less at positions (1) to (3) immediately after application for 3 minutes. And sufficient hydrophilicity is obtained.

  With respect to A and B, the contact angle returns considerably after one day at any position, and it is necessary to apply plasma again to restore hydrophilicity.

  Based on the above results, an electrode is provided on the surface or inside of a plate such as glass, mirror, or film, and plasma is generated on the surface to control the shape or movement of droplets existing on the surface or the hydrophilicity of the plate surface. Thus, a method or a wiper device for improving light transmission or light reflection was realized. By constructing many such electrode patterns on the glass surface, it is possible to provide a windshield device equipped with a wiper and a rearview mirror device equipped with a wiper.

  According to the present invention, it is possible to realize a windshield device and a rearview mirror device for a vehicle provided with an innovative wiper having no mechanical moving parts. Further, it can be used for the cleaning effect due to the improvement in hydrophilicity, for example, for the purpose of washing away dirt adhering to the surface of the solar cell panel plate by making the surface hydrophilic.

When water droplets adhere to the surface of the windshield or rearview mirror, plasma is generated on the surface, flattening the water droplets, improving light transmission or light reflection, and realizing a wiper function that secures external visibility 1 is a perspective view of a method or apparatus. It is a front view which shows the shape on the surface of the plasma electrode arrange | positioned on the glass in this invention, a mirror, or a film. It is a front view which shows the shape in the surface of another plasma electrode arrange | positioned on the glass in this invention, a mirror, or a film. It is a front view which shows the shape in the surface of another plasma electrode arrange | positioned on the glass in this invention, a mirror, or a film. It is a front view which shows the shape in the surface of another plasma electrode arrange | positioned on the glass in this invention, a mirror, or a film. It is a front view which shows the shape of the surface of another plasma electrode arrange | positioned on the glass in this invention, a mirror, or a film, and a back surface. It is a front view which shows the shape of the glass A with an electrode in the Example of this invention. It is a front view which shows the shape of the glass B with an electrode in the Example of this invention. It is a graph showing the measurement result of the waveform of the voltage V at the time of applying a pulse high voltage to the glass A with an electrode in the Example of this invention, and the electric current I. It is a graph showing the measurement result of the waveform of the voltage V at the time of applying a pulse high voltage to the glass B with an electrode in the Example of this invention, and the electric current I.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass 2 Back surface electrode 3 Front surface electrode 4 High voltage power supply 5 Droplet 6 Flat area 7 Polyester film 8 Pulse high voltage power supply 9 Needle-like electrode

Claims (3)

Plasma is generated by electrodes fixed on and in contact with the surface of the plate, and the light transmission of the plate is controlled by controlling the shape or movement of droplets existing on the surface or the hydrophilicity of the plate surface. How to improve.   A windshield device for a vehicle equipped with a wiper using the method of claim 1, wherein the plate is glass. 2. A vehicle rearview mirror device having a wiper using the method of claim 1, wherein the plate is a surface glass constituting a mirror.

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