Dial Plates For Timepieces

Abstract

A dial plate for timepieces consisting of a metallic base plate and a thin shell plate having a nacreous gloss and bonded to said metallic base plate with the nacreous surface thereof exposed to the outside by means of an adhesive, in which said thin shell plate is bonded to said metallic base plate at an opaque layer formed on said thin plate or plating applied to the back side thereof.

Description

This invention relates to dial plates for timepieces and more particularly to dial plates, for timepieces, having a remarkable decorative effect which is brought about by ingenious use of the aesthetic characteristics of shells.

Conventional dial plates for timepieces such as a watch, a wrist watch, a bracelet watch, a pendant watch and a finger ring watch are generally comprised of a base plate consisting of a brass plate or aluminum plate and color coating or plating layers applied thereto. A dial plate is one of the exterior accessories of portable timepieces which is attractive to the taste of the users and for which the aesthetic effect is required most. In this view, dial plates of various patterns and colors have been provided for said timepieces heretofore but the coloring of dial plates has provided only a limited variation in pattern and color, and been unable to sufficiently satisfy the demand for entirely novel dial plates. There has been known a so-called shell-enchasing technique in which iridescent flakes of shells are embedded in the lacquer surface layer of an article such as a paper container box or a cake bowl to produce a decorative effect, and various studies are being made in recent years on the application of such technique to portable timepiece dial plates to impart a decorative effect to the dial plates and thereby to enhance the commercial value of timepieces. However, in the conventional shell-enchasing technique an embedding method has in most cases been employed for securing the shell flakes to a substrate and such a method cannot be directly used in the manufacture of portable timepiece dial plates which are required to be as thin as possible. Under the circumstances, a method has been provided in which a thin sheet of shell material is laminated on the base plate of a dial plate by means of an adhesive or the like, but this method has had the disadvantage that an irregularity in application of the adhesive is visible through the laminated shell flake since the shell flake is extremely thin and semi-transparent, resulting in degradation of the aesthetic effect of the shell, and the method has not been applied in practical use.

There has also been proposed a dial plate for high grade portable timepieces which is made from a jewel such as ruby or sapphire per se. However, such a dial plate is extremely expensive and, in addition, the working on the jewel is extremely difficult because of its high hardness and especially the boring of small holes in the jewelry dial plate for implanting indexes or the like is difficult. Therefore, in such type of dial plate the time marks have in most cases been printed on the surface of the dial plate, but the printing of the time marks has proved unsatisfactory not only in that the printed marks are illegible but also in that a variety of time indexes cannot be used.

It is therefore the object of the present invention to provide novel dial plates for use in high grade portable timepieces, which are entirely different from and overcome the disadvantages of the conventional dial plates, which have a remarkable aesthetic effect and which can be produced in a mass production with ease and at low costs. According to the present invention there can be obtained dial plates which individually have different patterns and color hues to each other and hence each of which has a marked originality.

According to one aspect of the invention there is provided a dial plate which comprises a thin metallic base plate made from metal such as brass or aluminum and a thin plate of shell material laminated on said metallic base plate by means of applying adhesive, the bonding surface (hereinafter referred to as back surface) of said plate of shell material or shell flakes (hereafter "shell plate) with said metallic base plate being coated with a non-transparent coating layer, whereby an irregularity, if any, in application of said adhesive is not visible on the front surface of the dial plate and further the color hue of said paint layer and the optical refraction of the shell are ingeniously combined to produce a highly variable aesthetic effect. There is also provided a dial plate of the character described above, in which the surface (hereinafter referred to as front surface) of said thin shell plate is coated with a transparent or semi-transparent coating layer, whereby a unique change of color hue and gloss can be imparted to the dial plate. These optical effects are due to the combination effect of the ray reflected on the surface of the shell plate with the ray reflected on the surface of the transparent or semi-transparent coating layer. There is also provided a dial plate of the character described above, in which small holes are bored through the laminate of said thin shell plate and said metallic base plate, and separately provided types are implanted in said small through-holes.

According to another aspect of the invention there is provided a dial plate which comprises a thin metallic base plate made from brass or aluminum and a thin shell plate laminated on said metallic base plate by means of an adhesive, the bonding surface of said shell plate with said metallic base plate being plated by an electroless plating, whereby an irregularity, if any, in application of said adhesive is not visible on the surface of the dial plate and further the color hue of said non-electrode plating and the optical refraction of the shell are ingeniously combined to provide a highly variable aesthetic effect. There is also provided a dial plate of the character described above, in which the front surface of said thin shell plate is coated with a transparent or semi-transparent coating layer, whereby a unique variation of color hue and gloss can be imparted to the dial plate. There is also provided a dial plate of the character described above, in which small holes are bored through the laminate of said thin shell plate and said metallic base plate, and separately provided types are implanted in said small through-holes.

The present invention will be described by way of example hereunder with reference to the accompanying drawings, in which:

FIG. 1 is a top plan view of an embodiment of the dial plate according to the present invention;

FIG. 2 is a vertical sectional view, partially broken away, of the dial plate taken on the line II--II of FIG. 1; and

FIG. 3 is a fragmentary sectional view, partially broken away, of another embodiment of the dial plate according to this invention.

Referring to the drawings, a base plate 1 of the dial plate is made from a thin metallic sheet, such as a brass or aluminum sheet, by punching. The base plate 1 has legs 1a by which the dial plate 1 is secured to the watch movement (not shown). The base plate 1 is provided with a hole or perforation 1b at the center thereof for receiving the spindles of hour, minute and/or second hands (not shown) of the timepiece therein. A thin shell plate 2 is superimposed on the base plate 1, which is obtained by peeling the nacreous layer of a shell by a known method to make flakes. The thin shell plate 2 has a disc shape essentially same as the shape of the base plate 1 and is provided with a hole 2a at the center thereof in alignment with the hole 1b of the base plate 1. As the materials of the thin shell plate, the shells of shellfishes such as ear-shells, pearl shells, Mexican shells, black lips, yellow lips and other iridescent shells are suitably used. The shell plates made from said shells respectively have different optical tastes. The back side of the thin shell plate is coated with an opaque paint layer, such as a lacquer layer, or an electroless plating layer 3. The opaque coating layer 3 can be of an optional color hue and its color tone can be freely selected over a wide range. Further, the back side of the thin shell plate can be coated not only with a single paint of certain color but also with a combination of paints of different colors. On the other hand, where the back side of the thin shell plate 2 is coated with an electroless plating layer, such an electroless plating layer may be deposited directly on said thin shell plate. As the metals which can be used for the electroless plating layer there can be mentioned single metals such as nickel, cobalt, copper, silver, gold and platinum, and alloys such as nickel alloys and cobalt alloys. A remarkable decorative effect can be obtained particularly when silver or gold is used. By properly selecting the metal to be used, the color tone of the electroless plating layer can be optionally changed. Further, the back side of the thin shell plate can be coated not only with a single plating of certain color but also with a combination of platings of different colors.

The thin shell plate 2 described above is fastly adhered to the base plate 1 by means of an adhesive layer 4. As the adhesive, epoxy type adhesives which are widely used can be employed by the adhesive to be used is of course not limited only thereto. Although in the embodiment shown the adhesive layer 4 is provided over the entire area of the outside surface of the base plate 1, it has been revealed through testing of the actual product that the provision of the adhesive layer only at several locations on the base plate 1 is sufficient to prevent disengagement or distortion of the thin shell plate 2. Reference numeral 5 designates time markings provided on the surface of the dial plate, which are directly printed on the surface of the thin shell plate 2.

In the dial plate for portable timepieces according to the present invention, as described above, the opaque coating layer or electroless plating layer 3 are provided on the back surface of the thin shell plate 2, so that the adhesive layer provided between the surface of the base plate and the thin shell plate is not visible through said thin shell plate, and therefore, said thin plate 2 can be directly bonded to the base plate 1.

Namely, when the dial plate is viewed squarely from the front side thereof, an irregularity, if any, in application of the adhesive is not visible through the shell plate as it is covered with the opaque coating layer or electroless plating layer 3 and, therefore, the aesthetic effect of the dial plate is not impaired. Consequently, it is unnecessary to exercise unnecessary care during production of the dial plate and the dial plate can be produced by mass production system with ease. The aesthetic effect of the dial plate is brought about by the combined effect of the nacreous color and optical refraction characteristic of the thin shell plate 2 and the opaque coating layer or electroless plating layer 3. Thus, a high colorful dial plate emitting a variety of color lights can be obtained. Dial plates for use in portable timepieces are required to be as thin as possible. In this respect, the dial plate can be formed in the shape of a thin plate as a whole, as the shell plate 2 is adhesively bonded directly to the base plate 1. Namely, in the embodiment shown, the base plate 1 has a thickness of 400 microns and the shell plate 2 has a thickness from 200 to 250 microns so that the entire thickness of the dial plate may be as small as not greater than 700 microns. This brings about the additional advantage that usual apparatus for producing dial plates for thin portable timepieces can be used as such for the production of the dial plate of this invention.

FIG. 3 shows another embodiment of the dial plate according to this invention. This embodiment is similar to the preceding embodiment in that the thin shell plate 2 having the back surface thereof coated with opaque paint layer or electroless plating layer 3 is laminated to the base plate 1 by means of the adhesive layer 4, but is different from the preceding embodiment in that the front surface of said thin shell plate 2 is also coated with a paint layer 6. The paint layer 6 is formed of a transparent lacquer, semi-transparent lacquer or industrial varnish, and imparts various changes to the surface gloss of the plate 2 and slightly colors said plate. By properly selecting the coating materials used, an almost infinite number of color combinations can be obtained. It has been confirmed on the actual dial plate that, by applying the coating in a vignette type, a dial plate having a highly fantastic aesthetic effect can be obtained, and that the paint when applied uniformly on the plate of shell produces an iridescent pattern. It is also effective to apply the paint in such a manner that the color darkness of the paint is progressively increased toward the peripheral edge from the central portion of the dial plate where the coating layer is transparent. Reference numeral 7 in FIG. 3 designates time marking types provided on the front surface of the dial plate, which are separately made of such a metal as brass and coated with a plating, and are secured to the dial plate at its legs 7a which are extended in small holes, bored through the shell plate 2 and base plate 1 and fixed therein as by spot welding. The thin shell plate 2 of the dial plate according to the present invention is lower in hardness than jewelries, such as ruby, and therefore, can be worked relatively easily. The through-holes can be bored therein also by a conventional boring machine. This also facilitates the mass production of the dial plate without adding to the production cost.

As described hereinabove, the dial plates for timepieces, according to the present invention exhibit a variety of colors and patterns which are basically created by the nacreous color possessed by the shell and are variable in an indefinite number of ways in combination with the color or colors of the paint or paints used in a variety of ways, and which give a sense of quality to the dial plate. In addition, the dial plates of the invention can be produced in large quantities at low costs and the product dial plates individually have different aesthetic effects of their own and are entirely novel. It should be noted that the dial plates of the invention are not necessarily of round shape as shown in the embodiments but may be of square or rectangular or any other irregular shapes, and are of great practical commercial value.

Claims

What is claimed is:

1. A dial plate for timepieces, of the type comprising of a laminate of a thin metallic base plate and a thin shell plate bonded thereto by means of an adhesive, characterized in that said thin shell plate is adhered to said thin metallic base plate at an opaque layer applied to the substantially entire area of the back surface of said thin shell plate.

2. A dial plate for timepieces, according to claim 1, wherein the front surface of said thin shell plate is provided with a transparent coating layer.

3. A dial plate for timepiece, according to claim 1, wherein the front surface of said thin shell plate is provided with a semi-transparent coating layer.

4. A dial plate for timepieces, according to claim 1, wherein said opaque layer is formed by means of an electroless plating.

5. A dial plate for timepieces, according to claim 1, wherein said opaque layer is formed by coating of opaque paints.

6. A dial plate for timepieces, according to claim 1, wherein the laminate of said thin shell plate and said base plate is formed with small through-hole and time marking types having mounting legs are secured to the front surface of said thin shell plate by inserting said mounting legs into said small through-holes.