CH704601B1 - Pointer for measuring instruments, in particular watches, with optically excited waveguide. - Google Patents

Abstract

The present invention relates to pointers for measuring instruments, in particular watches, which achieve optically excited waveguides increased visibility with defined geometric and color properties. The pointer vane of the pointer according to the invention consists wholly or partly of at least one optical waveguide (6) with core and cladding, wherein the cladding carries excitation light and the core emits light in the visible range by fluorescence.

Description

Description Various methods that allow pointers of clocks or gauges to be seen even with limited brightness are known. For example, For example, a light source may be used to illuminate the dial (see US Patent 6,017,127 for dial illumination in watches). In a further example (WO / 1997/040 346), pointers are described with an electrically contacted light source (filament, light emitting diode = LED), which illuminates the pointer flag.

Other methods are based on phosphors which are applied to the hands by coating techniques. When, for example, phosphors containing phosphorescent pigments are used, electrons from certain ions contained in the pigments are excited by daylight or artificial light. After a storage phase, which depends on the intensity, the wavelength distribution and the duration of the illumination, the electrons fall back from their excited to their ground state. This releases energy that can be emitted in the form of visible light.

The invention has for its object to significantly improve the visibility of the pointer by arranged on the pointer flag optical waveguide: the waveguides are optically excited by a special process and can be made to shine in different colors and geometries. New features and design options are made possible at low cost.

The object is achieved by pointers having the features defined in the claims below and in the following examples. Some possible waveguide and illumination source arrangements are described.

The novel pointers have the advantage that the phosphors (which are present in the applied on the pointer flag waveguides) are excited only optically. Applications without electrical contact paths to the hands are conceivable. The hands are provided with optical waveguides, which can be installed in various arrangements in the pointer blade: this results in new design and color options.

Luminescent or phosphorescent substances with emission wavelengths in the range between about 400 and 700 nm and excitation wavelengths in the visible or UV range are well known. Examples are: inorganic rare earth minerals. Dopants: YVO 4: Eu, Y 2 O 2 S: Eu, Gd 2 O 2 S: Tb, Y 3 Al 2 O 12: Ce, (Ce, La) PO 4: Tb, BaMgAl14023: Eu, Sr 2 Al60ii: Eu, SrAl 2 O 4: Eu, Dy, CdSiO3: Mn, Y, Sr2MgSi207: Eu, AIN: Eu, Ba2Si5N8: Eu. -so-called "quantum dots" where an inorganic nanocrystal typically 2-10 nm in size (e.g., ZnS: Eu, Mn) is embedded in a matrix (e.g., glass). - organic compounds (phenoxazines, phenotyazines, phthalocyanines, naphthalocyanines, indolium derivatives, pyrillium derivatives, rare earth chelates, rhodamines, pyranines, triphenylmethane dyes, stilbenes, coumarins, etc.).

The luminescent or phosphorescent substances can be applied in various forms. For example, It is known that luminescent compounds in support materials (glass or plastic) can be embedded, dispersed or applied to surfaces. The support material may be in various forms such as e.g. Fibers with different geometries and cross-sections are further processed. The latter can be applied to the pointer flags or used directly as independent pointer flags.

A classic example of a waveguide is an optical fiber, with a "core" of about 10 pm in diameter and a cladding of about 300 pm in diameter. The refractive index of the core is higher than that of the shell, so that the light is kept. Multiple coats are possible. Various materials may be employed, such as e.g. Glasses or plastics. In one form of the invention, the core may be doped with luminescent or phosphorescent substances: the exciting light is guided in the cladding and stimulates the luminescence or phosphorus in the nucleus. In another, simpler form of application, a simple fiber (without a core / cladding structure) is used as the optical fiber: the fiber material contains the corresponding dopant and is excited by an external source of illumination, thereby causing it to fluoresce or phosphoresce.

Advantageous embodiments of the inventive pointer are described with reference to the embodiments illustrated in the following drawings.

Fig. 1 shows a view of a display device of a measuring device with pointer and scale. A pointer example is shown enlarged below, with all functional information. What is essential is the optical fiber ("(1)", for example, a plastic fiber) that is the inventory of the pointer. The light emitted by a source (not shown) is coupled into the light pipe. The light is guided in the light guide. The light guide is chosen so that in the core light conversion can take place by photoluminescence or phosphorescence. Photoluminescent or phosphorescent substances may e.g. Emit light in the visible wavelength range when excited in the blue or ultraviolet range. There are many examples of such substances. These include, as mentioned above, inorganic pigments that can be doped with different excitation centers. This can be used to create numerous colors or color combinations.

Fig. 2 is a perspective view of a clock with two inventive hands "(1)" and "(2)". The pointer "(1)" is provided with a light guide, which is smaller in area than the total area of the pointer flag. In contrast, Pointer "(2)" consists almost entirely of optical fiber material. Both variants can be made by means of the invention described herein: thereby a wide variety of design possibilities in terms of pointer shapes and colors can be covered.

Fig. 3a is a side view of a pointer according to the invention. The pointer turns around the axis «(11)». The pointer with optical light guide is illuminated by a light source «(1)» (eg an LED), which via a steel forming device «(2)» (eg a parabolic reflector) light into the channel «(3)» (eg a plastic fiber) couples. The light emerging from «(3)» is reflected by the mirror «(4)» and bundled with a lens «(5)». The bundled light beam is coupled into an optical waveguide "(6)" consisting of a core "(7)" and a cladding "(7)". By default, the refractive indices of the core and the cladding are chosen so that the light is guided in the core. Waveguides with multiple cladding arrangements can also be used. Essentially, as already mentioned in the description of FIG. 1, a substance characterized by favorable photoluminescence or phosphorescence properties is contained. This substance is excited by the light beam and then lights up. This afterglow can be adjusted by the choice of the substance and its doping to the desired wavelength distributions. Multiple cores, either nested or juxtaposed, are also usable. "(8)" is the actual pointer flag, mounted on a sleeve, which is driven by a mechanism not shown and the pointer makes its display function possible. To limit the excitation period of the waveguide to the necessary, the light source is turned on only for certain positions of the pointer. For example, in the case of a clock, the waveguide on the minute hand is excited several times per revolution. This allows control of the electrical power required for excitation. «(9)» is a covering device centered above the light source and on the axis «(11)». It serves as a protective device and can act as an element of the design through various variants.

Fig. 3b is a top view of the pointer described in Fig. 3a. The optical excitation source remains invisible: only its excitation effect in the form of the light emitted in the core of the waveguide is visible to the observer. It should be noted that the construction of the excitation source, which was described in Fig. 3a with separate parts, can also be made monolithic: conceivable are various monolithic combinations of, for example, reflector / light guide / mirror / lens in the form of a folded rod lens ,

Fig. 3c is also a top view of a pointer example. Thus, the possibilities for design variations can be indicated. By means of fiber bundles or Y-couplers, the waveguides can be added apart or in one another. This makes it possible to produce a variety of patterns on the pointer surface.

By compositional level in the core of the waveguide is also conceivable along the waveguide to change the intensity of the emitted light.

Fig. 4 is a side view of a system with two pointers according to the invention. The hands rotate around the axis «(11)».

The top pointer with optical fiber is illuminated by a light source «4» (eg an LED or a semiconductor laser with emission at 405 +/- 25 nm), which passes through the (movable) contacts «(1)» and «(2)» is electrically excited. The light emerging from (4) is coupled into the light-emitting waveguide via a steel forming device (7). As already described above, the core of the waveguide contains a substance characterized by favorable photoluminescence or phosphorescence properties. «(9)» refers to the metallic base of the pointer flag. Conceivable, however, is also a pointer flag, which consists entirely of lichtleitendem material, without metallic or other support. The description for the lower hand is similar: the light source «(5)» is excited by the contacts «(1)» and «(3)», the coupling of the light is transmitted via «(7)» into the waveguide «(8 ) »Coupled. A possible metallic pointer flag is marked «(9)».

In Fig. 5 an inventive display with waveguides is sketched without moving pointer flags. The waveguides are mounted on the dial. In the figure, 60 waveguides are arranged radially, so that a minute display can be made directly: every minute, another waveguide is successively excited. Excitation may be by a central axis rotating light source with an optical device similar to that in Fig. 3a or each waveguide may be directly coupled to an excitation source (e.g., at the outer ends of the waveguides) and individually driven. An hour indication can be made via other waveguides of other lengths and optical properties (such as the wavelength or color of emitted fluorescence). Many different display variants are possible. The production of the waveguides and in principle also the integration of the light sources can be done inexpensively with lithographic techniques or hybrid construction techniques.

List of Figures: [0017]

Fig. 1 indicating instrument with pointer and scale. The pointer consists of a pointer flag with optical fiber.

Fig. 2 o'clock with two hands: Pointer (1) consists partially, pointer (2) consists entirely of an optical light guide.

Claims (10)

Fig. 3a Detailed side view of a pointer with optical fiber. Fig. 3b top view of a pointer with a simple optical fiber having a constant cross section over the entire usable length. Fig. 3c top view of a pointer with a light guide having a variable cross section over the entire usable length. Two Y couplers are used for this. Fig. 4 side view of two superimposed pointers with optical fibers. Fig. 5 display with arranged on the dial waveguides. claims 1. Pointer for measuring instruments, in particular watches, characterized in that the pointer vane of the pointer wholly or partly consists of at least one optical waveguide with core and cladding, wherein the cladding of the waveguide excitation light and the core emits light by fluorescence in the visible range. 2. A pointer according to claim 1, characterized in that the optical waveguide consists of a fiber designed as a fiber. 3. Pointer according to claim 1, characterized in that organic, inorganic or nanocrystalline phosphors are contained in the core of the waveguide. 4. A pointer according to claim 3, characterized in that the distribution of the phosphors has a locally dependent concentration in the core, wherein the changes in the phosphor concentration generates a location-dependent light conversion efficiency. 5. A pointer according to claim 1, characterized in that the pointer vane consists at least partially of a waveguide formed as an optical fiber. 6. Pointer according to one of claims 1 and 5, characterized in that the pointer flag is excited during the rotational movement of the pointer by incident from different directions excitation light. 7. A pointer according to any one of claims 1, 5 and 6, characterized in that at least two simple waveguides are joined together in a consisting of at least two waveguides multiple waveguide by coupling to a common waveguide in Y-shape. 8. measuring instrument, in particular clock, with at least two pointers according to one of the preceding claims 1 to 7, characterized in that the pointers rotate about different mechanical axes. 9. measuring instrument, in particular clock, with at least two pointers according to one of the preceding claims 1 to 7, characterized in that the pointer-forming waveguide mounted on a base, in particular inserted, or engraved. 10. measuring instrument, in particular clock, according to claim 9, characterized in that the excitation light comes from a light source, which is located on the outer edge of the pad.