GB2030171A

GB2030171A - Luminous laminate for use in instrument dials and method of making laminate

Info

Publication number: GB2030171A
Application number: GB7930260A
Authority: GB
Original assignee: CENTURION COMPONENTS Ltd
Current assignee: CENTURION COMPONENTS Ltd
Priority date: 1978-09-12
Filing date: 1979-08-31
Publication date: 1980-04-02

Abstract

The present invention relates to a laminate suitable for use in instrument dials which avoids the potentially hasardous direct exposure of operatives involved in instrument assembly to luminising compounds. The laminate comprises a first substantially translucent film 1, a second film 2 and a layer of luminous material 3 sandwiched therebetween. In a method of the invention the luminous markings 3 are applied to one of the films 1, 2 and then covered with the other of said films 2, 1. The luminous material is activated by tritium. The laminate may be used for dials or hands on dials. <IMAGE>

Description

SPECIFICATION Laminate for use in instrument dials and method of making laminate The present invention relates to a laminate suitable for use in the production of time pieces or other instrument having dials and/or hands, with luminous markings.

Conventionally the luminous markings are applied to instrument dials and hands by manual painting of luminous compound on to the dial or hand.

Since luminous materials are generally radioactive to a greater or lesser extent, such an operation exposes the operative to a significant health hazard so that special precautions need to be taken to provide a safe working environment to protect the operative making the instrument.

It is an object of the invention to provide an improved method of applying luminous markings to instrument dials and hands and a laminate suitable therefor.

The present invention provides a laminate suitable for use in the production of luminous timepieces or other instruments having dials and/or hands with luminous markings, said laminate comprising a first substantially translucent film, a layer of luminous material, and a second film, said luminous material being sandwiched between said first and second films.

in another aspect the present invention provides a method of making a laminate of the invention comprising the steps of applying the luminous markings to one of a first substantially translucent film and a second film, and then covering the luminous material with the other of said first substantially translucent film and second film.

In a further aspect the present invention provides a method of making an instrument dial and/or hand with luminous markings characterised in that a laminate of the invention is applied to the instrument face and/or hand respectively. Alternatively if the laminate has adequate rigidity, it can itself be formed into an instrument dial or hand.

Any conventional luminising compound such as for example a compound containing radio-active tritium may be used in accordance with the present invention.

The first and second films may be of any material that can be formed into a film, provided that in the case of the first film a sufficient degree of light transmission is provided. Most desirably in the case of the first film, the material is transparent.

Advantageously the film materials are selected so as to be reasonably impermeable to minimise physical leakage of luminising compound from within the laminate. The film material may also be selected to minimise leakage of radio-activity from one or other side of the laminate.

In general, particularly suitable film materials are plastics materials. In addition to having some or all of the desirable features mentioned above, they are generally readily tractable, economic to use and provide good strength whilst enabling the production of laminates ranging from flexible to substantially rigid. In general, thin flexible laminates are preferable when these are to be applied to a rigid sub-strate such as an instrument face or hand. On the other hand where a laminate is sufficiently thick and/or rigid this can itself be used to form the instrument face or hand.

Conveniently one or other of the films may be provided with additional markings and/or decorative material in non-luminous compound. This can be particularly advantageous in the production of instrument dials where only some of the markings are desired to be luminous. Thus for example in the case of a watch dial the laminate may be formed from a first transparent film on to the back of which are reverse printed non-luminous markings and the luminising compound applied, these then being covered wirth the second film so that the luminising compound is sealed in. Many other different embodiments and combinations are, however, also possible. Thus, for example, the non-luminous markings may be applied to the front of the first film.

Alternatively if both the first and second films are made of a substantially transparent film then the non-luminous markings may be applied directly to the instrument dial and the laminate then placed over them. Yet another possibility in this case is to use a separate further film or laminate for the non-luminous markings and then superimpose the further film or laminate above or below the laminate of the invention.

The laminate may be made in any desired shape or form. Thus, for example, the laminate may be made in the form of a single dial or hand; or in the form of a larger sheet which can be subsequently cut down to provide one or more "dials" (including laminate portions suitable for forming dials or for application to dials) and/or one or more hands (including laminate portions suitable for forming hands or for application to hands).

Whilst the laminate will generally be made in the form of a flat sheet it can also be made in non-planar forms, e.g. as a convex dish-shape suitable for application to a convex instrument face.

It will be appreciated that the laminate of the invention provides a safe and ready-to-use component in the assembly of instruments and that any operations involving the direct exposure of operatives to luminising compound may be separated entirely from any instrument assembly areas thereby facilitating the maintenance of safe working conditions as far as possible.

One way of carrying out the invention is described in detail below with reference to the accompanying drawings which illustrate only one specific embodiment, in which: Figure lisa plan view of a laminate for a watch dial; and Figure 2 is a partial sectional view of the laminate of Figure 1.

Figures 1 and 2 show a laminate comprising a facing film 1, a backing film 2 and luminous markings 3 of luminising compound sandwiched therebetween. The backing film 2 is substantially opaque and/or light reflective and has a colour, e.g. black or white, chosen to provide a good contrast between itself and the markings 3. The facing film 1 is substantially transparent to allow maximum visibility of the luminous markings 3.

Example The facing film comprises an 0.025 inches (0.625 mm) thick layer of a transparent plastics material selected from P.V.C., Acetate and Celluloid. The backing film comprises an 0.025 inches (0.625 mm) thick layer of an opaque plastics or metal material selected from P.V.C. (plyvinylchloride), a styrene polymer and aluminium. The markings are made of a tritium luminising compound.

Claims

1. A laminate suitable for use in the production of luminous timepieces or other instruments having dials and/or hands with luminous markings, said laminate comprising a first substantially translucent film, a layer of luminous material, and a second film, said luminous material being sandwiched between said first and second films.

2. A laminate as claimed in claim 1 wherein the first film is substantially transparent.

3. A laminate as claimed in claim 1 or claim 2 wherein at least one of the first and second films is rigid or semi-rigid.

4. A laminate as claimed in any one of the preceding claims wherein at least one of said films is of a plastics material.

5. A laminate as claimed in any one of claims 1 to 4wherein the layer of luminous material is in the form of a plurality of indicia or other discrete luminous markings.

6. A laminate as claimed in any of claims 1 to 5 in which are also provided non-luminous markings.

7. A laminate as claimed in claim 6 wherein the non-luminous markings are provided on a third film included in said laminate.

8. A laminate as claimed in any one of claims 1 to 7 which has a convex dish-shape.

9. A method of making a laminate according to claim 1 comprising the steps of applying luminous material to one of a first substantially translucent film and a second film, and then covering the luminous material with the other of said first substantially translucent film and said second film.

10. A method as claimed in claim 9 which includes the step of sealing the first and second films together.

11. A method as claimed in claim 10 wherein the firms are welded together.

12. A method as claimed in any one of claims 9 to 11 in which the luminous material is painted onto the film.

13. A method as claimed in any one of claims 9 to 11 in which the luminous material is printed onto the film.

14. A method as claimed in any one of claims 9 to 13 which includes the steps of forming the laminate into a convex dished-shape.

15. An instrument dial or hand which is formed of a laminate according to any one of claims 1 to 8.

16. A method of making an instrument dial or hand having luminous markings comprising applying a laminate according to claim 1 to the instrument dial or hand.

17. A method of making an instrument dial or hand having luminous markings comprising forming a laminate according to claim 1 into the shape of said dial or hand.

18. A laminate for use in the production of an instrument having a dial and/or hands with luminous markings according to claim 1 substantially as described hereinbefore with particular reference to Figures 1 and 2 ofthe accompanying drawings.

19. A method of making a laminate according to claim 9 substantially as described hereinbefore with particular reference to Figures 1 and 2 of the accompanying drawings.