Coating processes – Direct application of electrical – magnetic – wave – or... – Pretreatment of substrate or post-treatment of coated substrate
Reexamination Certificate
2002-01-29
2004-02-03
Pianalto, Bernard (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Pretreatment of substrate or post-treatment of coated substrate
C427S348000, C427S407200, C427S421100, C427S569000, C427S579000
Reexamination Certificate
active
06685992
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for partially treating a water-repellent glass sheet to remove part of a water-repellent function of the glass sheet. The invention also relates to a water-repellent glass sheet with part of its water-repellent film removed.
BACKGROUND ART
In recent years, water-repellent glass sheets are widely used on vehicles so as to repel rain drops from fields of view of drivers of the vehicles to thereby ensure safety driving in a rainy weather.
Such glass sheets are known from, for example, Japanese Patent Laid-Open Publication Nos. HEI-4-130032 and HEI-4-305037. The glass sheet disclosed in Japanese Patent Laid-Open Publication No. HEI-4-130032 includes a glass substrate, a film of SiO
2
(silicon dioxide) formed on the glass substrate, and a fluorine-based film such as that of fluorosilicon coated on the film of SiO
2
. The fluorine-based film provides a desired water-repellent function. In Japanese Patent Laid-Open Publication No. HEI-4-305037, the glass sheet is disclosed which comprises a glass substrate, a film of SiO
2
formed on the glass substrate, and a fluorine-containing carbonaceous film formed on the film of SiO
2
. The fluorine-containing carbonaceous film provides a desired water-repellent function.
These glass sheets have prolonged lives because the water-repellent films formed thereon do not peel off easily.
Of vehicular glass sheets, a water-repellent pane of glass provided sidewardly of a vehicle has a lower portion connected to a lift mechanism called a window regulator for raising and lowering the pane of glass. More specifically, the water-repellent pane of glass is connected to holders of metal by means of resin or adhesive applied thereto. The holders are then bolted to arms of the lift mechanism. The holder can be readily adhered to a laminated glass pane or another glass pane free from a water-repellent function. However, a problem is encountered in connecting the holders to a water-repellent pane of glass by means of an adhesive. More specifically, it is impossible to achieve a required adhesive strength between the adhesive and the glass pane because the water-repellent film of the water-repellent pane of glass functions to repel the adhesive. As a consequence, the holders cannot be attached to the water-repellent glass pane. To overcome this problem, either abrasives (abrasive method) or masking tapes (masking tape method) have been conventionally used.
In the abrasive method, portions of the water-repellent film that are to be connected to the holders are scraped off mechanically by use of the abrasives containing small particles of silicon oxide or cerium oxide, thereby providing the water-repellent pane of glass having parts free of the water-repellent film. Such water-repellent-film-free parts of the glass pane can then be connected to the holders through an adhesive applied thereto.
In the masking tape method, portions of a pane of glass that are to be connected to the holders are masked by applying a masking tape thereto. A water-repellent film is then formed on the glass pane having the masked portions. Thereafter, the masking tape is peeled off from the glass pane, thereby providing the water-repellent glass pane with the portions free of the water-repellent film. Such water-repellent-film-free portions of the glass pane can then be connected to the holders through an adhesive applied thereto.
However, in the abrasive method, it is difficult and laborious to partially remove the water-repellent film by means of abrasives, thereby increasing the cost of processing of the water-repellent film.
Again, in the masking tape method, it is troublesome and laborious to apply masking tapes to the glass pane and to peel off the tapes from the glass pane. Further, it is quite difficult to achieve minute masking on the glass pane. Thus, the masking tape method is not effective for a curved pane of glass.
Reference is now made to
FIG. 8
hereof schematically illustrating a conventional front glass pane or windshield. As in some conventional windshields, the illustrated windshield
101
includes wipers
102
,
102
movable across the windshield to remove rain, and optical instruments such as a rain sensor
103
for detecting whether any rain drops are present on the windshield, or the amount of the rain drops on the windshield.
In
FIG. 9
, the windshield
101
with the rain sensor
103
is illustrated in enlarged-scale partial cross section taken along line
9
—
9
of FIG.
8
. The windshield
101
has a water-repellent film
104
formed on an external surface of the windshield
101
. The water-repellent function of the film
104
becomes gradually degraded with the lapse of years. In correspondence with the degradation, the states of adherence of rain to the windshield
101
also change. It is quite tedious to make the relevant control follow those changes. In the light of the tedious adjustments thus required of the control to follow the changes, the front glass pane
101
may as well go without the water-repellent film
104
.
To this end, one may propose to provide a small window-shaped water-repellent-film-free part
105
so that the rain sensor
103
can be mounted to the windshield
101
in opposed relation to the film-free part
105
. This arrangement enables automatic wiping wherein the wipers
102
,
102
are automatically operated in correspondence with the amount of rain present on the film-free or non-repellent part
105
of the windshield
101
. It also becomes possible to urge, by signals, or phonetic or optical means, a driver to start the wipers.
Incidentally, for prolonging the life of the water-repellent film
104
, it is desirable to provide a relatively thick ground film or undercoat of SiO
2
interposed between the water-repellent film
104
and the front glass pane
101
.
Now, the non-repellent part
105
may be formed in the water-repellent film
104
and the ground film laid thereunder by using either the abrasive method or the masking tape method. However, since the water-repellent film
104
is relatively thick, resulted edges
106
of the film
104
inevitably lie perpendicularly to a windshield surface on which the water-repellent film
104
is formed. Thus, it is liable to happen that an incident ray
107
originating from a source of light such as light of a car running on an opposite lane is reflected by the edges
106
to thereby cause mis-detection of the rain sensor
103
. The abrasive method and the masking tape method are therefore not suited to form the window-shaped non-repellent part
105
in front of the sensor.
Reference is made next to
FIG. 10
which schematically illustrates interrelations between a conventional door glass pane and a conventional door mirror. A driver, not shown but seated in a driver seat
111
with his hands held onto a steering wheel
112
, looks into the door mirror
115
through the door glass pane
114
for rearward confirmation.
A front glass pane
116
has a water-repellent function because rain falls directly onto it. In contrast, the sideward door glass pane
114
normally comprises a non-water-repellent sheet of glass. It is, however, desirable that the door glass pane
114
has a water-repellent part
117
, as illustrated, so that the driver can obtain a clear rear view of the mirror through the water-repellent part.
As can be readily appreciated, the water-repellent part
117
is surrounded by a non-water-repellent part
118
of the door glass pane
114
. When the non-water-repellent part
118
is provided by means of the abrasive method or the masking tape method, an edge
119
of the water-repellent part
117
lies normal to a surface of the door glass pane
114
. Then, it is likely that the edge
119
, when shone with rays of light from a succeeding car or a passing-by car, or with roadside lights, undesirably serves as a reflecting surface and shines to thereby block the driver's rear view. In this instance, the water-repellent part
117
loses its significance of being provided.
DISCLOSURE OF THE INVENTION
It is accordin
Kobayashi Hiroaki
Kuramoto Shunji
Ogawa Hisashi
Teranishi Toyoyuki
Yamamoto Hiroaki
Merchant & Gould P.C.
Nippon Sheet Glass Co. Ltd.
Pianalto Bernard
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