Gaseous tritium light source

Abstract

A gaseous tritium light source (GTLS), which has a hermetically sealed outer sleeve made of glass, more particularly borosilicate glass. A high durability and lighting intensity is produced due to the fact that at least some sections of the outer sleeve have an outer coating applied directly to the outer surface of the outer sleeve serving as a reflective layer made of a metal, wherein the outer coating has an epitaxial structure and wherein the metal has a reflectance of >70% for visible light.

Claims

1. A gaseous tritium light source (GTLS), comprising: a hermetically sealed outer sleeve made of glass, coated on an inner surface with a luminophore, and filled with gaseous tritium, wherein at least some sections of the outer sleeve have an outer coating applied directly to an outer surface of the outer sleeve, the outer sleeve having a circumference surface with the outer coating provided on the circumference surface and with the outer coating serving as a reflective layer made of a metal, wherein the metal has a reflectance of >70% for visible light, wherein the metallic outer coating is a thin film having a thickness in a range from 30 to 500 nm and wherein the gaseous tritium light source has an average luminance (L)>1.7 [cd/m.sup.2].

2. The gaseous tritium light source according to claim 1, wherein the reflectance of the metal is >80% for visible light with a wavelength in a range from 400 to 730 nm.

3. The gaseous tritium light source according to claim 1, wherein the metallic outer coating contains aluminum (Al) or silver (Ag).

4. The gaseous tritium light source according to claim 1, wherein the metallic outer coating consists of aluminum (Al) or silver (Ag).

5. The gaseous tritium light source according to claim 1, wherein the metallic outer coating is completely covered by a protective coating.

6. The gaseous tritium light source according to claim 5, wherein the protective coating consists of a ceramic coating or a metallic coating.

7. The gaseous tritium light source according to claim 5, wherein the protective coating consists of one of the group consisting of: a SiO.sub.2 layer, an Al.sub.2O.sub.3 layer, a Ni layer, a Cr layer, and a NiCr layer.

8. The gaseous tritium light source according to claim 1, wherein the outer sleeve has a first end on which the outer coating is provided.

9. The gaseous tritium light source according to claim 8, wherein the outer sleeve has a second end that is not covered by the outer coating.

10. The gaseous tritium light source according to claim 1, wherein the outer sleeve has a circumference surface and the outer coating is provided over an entire area of the circumference surface.

11. The gaseous tritium light source according to claim 1, wherein the outer sleeve has a first end, and the outer coating is provided over an entire area of the first end.

12. The gaseous tritium light source according to claim 1, wherein the outer sleeve of the gaseous tritium light source has a diameter of 2 mm, and/or a length of 10 mm.

13. A timepiece comprising the gaseous tritium light source according to claim 1.

14. An insert, comprising: the gaseous tritium light source according to claim 1; and a plastic housing that at least partially encloses the gaseous tritium light source.

15. A sight comprising the insert according to claim 14.

16. A firearm comprising the sight according to claim 15.

17. A firearm comprising the insert according to claim 14.

18. The insert according to claim 14, wherein the plastic housing is made of transparent plastic.

19. The gaseous tritium light source according to claim 1, wherein the outer coating has an epitaxial structure.

20. The gaseous tritium light source according to claim 5, wherein the protective coating consists of one of the group consisting of: a Ni layer, a Cr layer, and a NiCr layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The subject matter of the invention is shown in greater detail by way of example in the figures based on an embodiment variant. In the drawings:

(2) FIG. 1 shows a cross-sectional view through a gaseous tritium light source,

(3) FIG. 2 shows a detail view from FIG. 1, and

(4) FIG. 3 shows an insert with the gaseous tritium light source according to FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) FIG. 1 shows a gaseous tritium light source (GTLS) 1 with a hermetically sealed outer sleeve 2 made of glass, namely borosilicate glass. The essentially cylindrical outer sleeve 2 has for example an inner diameter d of 1.2 mm (millimeters) and a length 1 of 6 mm.

(6) An inner coating 4 with a luminophore such as zinc sulfide is provided on the inside 3a of the outer sleeve 2. The outer sleeve 2 is filled with gaseous tritium 5, whose emitted radioactive radiation excites the zinc sulfide to emit visible light 6. This visible light is essentially emitted via the entire outer sleeve 2.

(7) To increase the luminance of the emitted visible light 6, the invention proposes for the outer surface 3b of the outer sleeve 2 to have an outer coating 7 made of a metal. This outer coating 7 is applied directly to the outer surface 3b and is provided in some areas thereof. In addition, this outer coating 7 has an epitaxial structure. Furthermore, the reflectance of the metal of the outer coating 7 is >70% for visible light. This increases the luminance L of the gaseous tritium light source (GTLS) in comparison to known gaseous tritium light sources in a surprising wayas is clear from Table 1.

(8) TABLE-US-00001 TABLE 1 Measurement results GTLS 1 to GTLS 6 Luminance Relative at 530 nm luminance Examples Outer sleeve [cd/m.sup.2] [%] GTLS1 Blank 1 100 GTLS2 Plastic housing (white) 1.5 150 GTLS3 Applied adhesive 1.55 155 with TiO.sub.2 particles GTLS4 Al housing 1.2 120 GTLS5 Al thin film 2.0 200 GTLS6 Al thin film and 2.2 220 SiO.sub.2 protective coating

(9) Example GTLS1 shows the prior art of gaseous tritium light sources with a blank outer sleeve made of borosilicate glass. Examples GTLS2 to GTLS4 show known uses of example GTLS1. In example GTLS2, a GTLS1 of this kind with a blank outer sleeve is enclosed in a white plastic housing. GTLS3 shows a GTLS1 with an adhesive containing TiO.sub.2 particles applied to the outer sleeve. GTLS4 encloses the GTLS1 (blank outer sleeve) with an AI housingspecifically, the gaseous tritium light source is inserted without adhesive into a blind bore in the aluminum housing.

(10) Examples GTLS5 and GTLS6 are embodiments according to the invention in which the outer sleeve 7 has an AI thin film (GTLS5) or an AI thin film and an Al.sub.2O.sub.3 protective coating 8 embodied as a thin film (GTLS6).

(11) In GTLS2 to GTLS6, the outer sleeve is uncovered or blank only at one end of the gaseous tritium light source. The luminance of the green light emitted by the gaseous tritium light sources (wavelength 530 nm) normal to these ends is measured with the PR-740 spectroradiometer made by Photo Research, Inc.

(12) As a comparison of examples GTLS1 to GTLS4 with the examples GTLS5 and GTLS6 according to the invention demonstrates, a surprising improvement in the luminanceat the 530 nm (nanometer) wavelength of the emitted light 6is apparent. In terms of the luminance, GTLS5 and GTLS6 even significantly outperform an outer sleeve of borosilicate glass onto which adhesive with TiO.sub.2 particles is appliedwhich according to the current consensus among experts, should be the most effective measure for increasing luminance in GTLS.

(13) The reflectance of the coating material AI is also >80%, namely 93%, for visible light with a wavelength in the range from 400 to 730 nm, namely of 530 nmwhich increases the luminance to 2 [cd/m.sup.2] or doubles it in comparison to the GTLS1 gaseous tritium light source.

(14) For this purpose, AI is applied as a thin film to the outer surface 3b the outer sleeve 2 by means of a PVD method. This makes it possible to achieve an outer coating 7 with an average layer thickness of 100 nmi.e. within the range from 30 to 500 nm.

(15) The outer coating 7 is protected from mechanical and chemical attacks by an Al.sub.2O.sub.3 protective coating 8, which is likewise applied as a thin film by means of a PVD method. This provides the outer sleeve 2 with a thin film composite 9 made of two thin films, which adheres in a particularly powerful way to the outer sleeve 2 made of borosilicate glass. This further increases the durability of the gaseous tritium light source 1.

(16) Preferably, the protective coating 8 completely covers the outer coating 7, as is clear from FIGS. 1 and 2. This is shown, for example, in FIG. 2, where the layer end 8a of the protective coating 8 encloses the end of the outer coating 7.

(17) It is also clear from Table 1 that surprisingly, a further increase in the luminance of GTLS6 to 2.2 [cd/m.sup.2] can be achievednamely by 10% in comparison to GTLS5 according to the invention.

(18) As can be inferred from FIG. 1, the outer sleeve 2 has a circumference surface 10a, which is provided with the outer coating 7 over its entire area. The outer coating 7 also covers the entire area of a first end 10b as shown in FIG. 1. Only the second end 10c is not covered by the outer coating 7. The gaseous tritium light source 1 therefore has a particularly high luminance at this second end 10c.

(19) To protect the gaseous tritium light source 1, it is embedded in a plastic housing 11, as shown in FIG. 3. It is thus possible for the gaseous tritium light source 1 to be used in the form of an insert 12, for example in a sight 100 on a barrel 104 of a firearm 101 or for example in a timepiece 111not shown. For example, the insert 12 is glued to the sight 100 by means of an adhesive that is not shown.

(20) The outer coating 7 eliminates the need for a reflective effect of a plastic housing 11 that is required in the prior art so that this housing can also be embodied as transparent and/or as consisting of two shells 11a, 11b. This is advantageous particularly if an optical lens 13 is likewise inserted into the plastic housing 11 and thus significantly simplifies the design of such an insert 12.

(21) The descriptions and figures included herein depict specific implementations to teach those skilled in the art how to make and use the best option. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these implementations that fall within the scope of the invention. Those skilled in the art will also appreciate that the features described above can be combined in various ways to form multiple implementations. As a result, the invention is not limited to the specific implementations described above, but only by the claims and their equivalents.