Patent Description:
Furthermore, the present invention relates to a method for providing measuring light for a chromatic confocal measuring device for determining one or more properties of a surface of an object.

There exists a variety of designs of lighting arrangements for providing measuring light for optical measurement devices. For example, <CIT> discloses a luminescence-based light source utilised in a chromatic confocal measuring device, wherein the light source includes a luminophore whose oblong exit surface emits polychromatic measuring light when the luminophore being illuminated by pump light. However, there still exists a need for improving operational efficiency in providing luminescence-based measuring light.

In accordance with the present invention, a chromatic confocal measuring device and related method for providing measuring light is provided in the independent claims. Some advantageous embodiments of the invention are inter alia disclosed in the dependent claims. An aspect of this application is to advance the art of illuminating and optical measuring systems.

It is another aspect of this application to provide in whole or in part, at least the advantages described herein.

There is provided a lighting assembly for providing measuring light for optical measuring device, that includes an aperture component comprising a first and opposite second side and at least one orifice, at least one pump light source to provide pump light, and a photoluminescent component. The photoluminescent component locates on the second side of the aperture component and is configured for converting pump light receivable onto the photoluminescent component from the at least one pump light source into polychromatic measuring light. At least part of the polychromatic measuring light is arranged to pass through the at least one orifice from the second side of the aperture component to provide measuring light to the first side of the aperture component. In this lighting assembly the pump light source locates on the first side of the aperture component.

There is provided a lighting assembly, where the pump light and the measuring light may be arranged to pass through the same the at least one orifice of the aperture component. The pump light may be arranged to pass through the orifice from the first side and the measuring light may be arranged to pass through the orifice from the second side of the aperture component, respectively.

There is provided a lighting assembly, where the material of the aperture component may be transparent for the pump light and nontransparent for the measuring light.

There is provided a lighting assembly, where the second side of the aperture component may be at least partially reflectable for the pump light and/or the measuring light.

There is provided a lighting assembly, where the lighting assembly may further comprise a substrate component attached to a side of the photoluminescent component opposite to another side of the photoluminescent component towards the second side of the aperture component.

There is provided a lighting assembly, where the aperture component, the photoluminescent component and the substrate component may be attached to each other forming a multilayer structure such that the photoluminescent component is at least partially sandwiched between the substrate component and the aperture component.

There is provided a lighting assembly, where the assembly may further comprise an optical connecting component disposed on the first side of the aperture component such that the pump light is inputtable and directable via the connecting component to the at least one orifice.

There is provided a lighting assembly, where the connecting component may be a beam splitter or dichroic filter, wherein the measuring light being allowed to pass through the connection component.

There is provided a lighting assembly, wherein the connection component may be a mirror or optical fiber.

According to the invention, the at least one orifice comprises a plurality of punctiform orifices or shaped orifice.

There is provided a lighting assembly, where the aperture component may comprise a masking, preferably metal film, layer on the photoluminescent component, being preferably produced by deposition technology.

There is provided a lighting assembly, where the lighting assembly may further comprise an optically transmissive substrate located on the first side of the aperture component, wherein the aperture component comprises a masking, preferably metal film, layer on a side of the transmissive substrate towards the luminescent component. The masking is preferably produced by deposition technology.

There is provided an optical measuring device, where the optical measuring device may comprise imaging optics, wherein the at least one pump light source and the connecting component of the lighting assembly and the imaging optics of the measuring device are disposed in relation to the at least one orifice of the lighting assembly such that the pump light provided from the pump light source is inputtable and directable via the connection component through the imaging optics, and hence is focusable through the imaging optics to the at least one orifice, and that the measuring light passed through the at least one orifice is collectable by the imaging optics.

According to the invention, there is provided a chromatic confocal measuring device for determining of one or more properties of a surface of the object. The chromatic confocal measuring device comprises the above-mentioned lighting assembly.

The property being determined may be distance; height or position; refraction index; a thickness; reflectance or roughness, for example.

There is also provided a method for providing measuring light for a chromatic confocal measuring device for determining of one or more properties of a surface of an object, that includes at least directing pump light from at least one pump light source through at least one orifice of an aperture component onto a photoluminescent component locating on a second side of the aperture component, the pump light being directed from a first side to the second side of the aperture component, converting part of the pump light in the luminescent component into polychromatic measuring light, and providing measuring light to the first side of the aperture component by allowing part of the measuring light pass the aperture component through the at least one orifice, wherein the at least one orifice comprises a slit-shaped orifice or a plurality of punctiform orifices.

In this document by a photoluminescent component is meant a piece of material, e.g., a plate, layer, slab or coating, including or consisting either of a single crystal or of pressed, sputtered or sprayed powder of at least one of fluorescent, phosphorescent and luminophore substances. The photoluminescent component is designed to receive electromagnetic radiation such as pump light of certain wavelength(s) and is capable of converting the pump light absorbed into the photoluminescent component into a broader band of wavelengths of light (i.e., polychromatic light) in phosphorescence and/or fluorescence process.

The present invention offers advantages over the known prior art, such as it may allow to focus pump light precisely to cover an orifice of the aperture component and hence the area of the luminescent component behind the orifice, which may provide as high intense measuring light as possible with the pump light directed to the aperture component.

Another advantage of the invention is that it may allow to modify spatial intensity distribution of measuring light provided through an orifice of the aperture component.

Still another advantage of the invention is that it may allow to provide pump light with high efficiency and high radiance since pump light can be directed at the luminescent component and creating a tightly focused and homogenous illumination area on a surface of the luminescent component that corresponds essentially the form and area of the orifice through which the measuring light is allowed to pass.

Still another advantage of the invention is that it may allow defining and providing the measuring light essentially in a form or shape of the orifice.

Still another advantage of the invention is that it may allow configuring the lighting assembly with lower number and/or complexity of the components than it is required with the conventional lighting assemblies or luminophore/luminescent light sources to provide said measuring light.

Still another advantage of the invention is that the cooling of the luminescent component may be implemented more effectively and the luminescent component may require less cooling than in the conventional lighting assemblies or luminophore/luminescent light sources utilising transmission luminescence for providing measuring light.

Still another advantage of the invention is that imaging optics of the measuring device using can be used for collecting and focusing the pump light to the luminescent component and for collecting the measuring light passed through the at least orifice.

The expression "a number of" may herein refer to any positive integer starting from one (<NUM>).

The expression "a plurality of" may refer to any positive integer starting from two (<NUM>), respectively.

The terms "first" and "second" are herein used to distinguish one element from the other element, and not to specially prioritize or order them, if not otherwise explicitly stated.

The previously presented considerations concerning the various aspects of the lighting assembly may be flexibly applied to the aspects of the method mutatis mutandis, and vice versa, as being appreciated by a skilled person.

The embodiments in the following detailed description are given as examples only and someone skilled in the art can carry out the invention also in some other way than what is described in the description. Most embodiments can be actualised in a variety of combinations with other embodiments. Though the description may refer to a certain embodiment or embodiments in several places, this does not imply that the reference is directed towards only one described embodiment or that the described characteristic is usable only in one described embodiment. The individual characteristics of a plurality of embodiments may be combined and new embodiments of the invention may thus be provided.

The foregoing and other objects, features, and further advantages of the invention will be apparent from the following more particular description of the embodiments of the invention, as illustrated in the accompanying drawings (the elements of the drawings are not necessarily to scale relative to each other), in which:.

In respective figures, the same or corresponding parts are denoted by the same reference numerals, and in most cases duplicate textual description will be omitted as well.

<FIG> illustrate, by means of a schematic side views, many general concepts of various embodiments of the present invention via one, merely exemplary, realisation of a lighting assembly at <NUM> for providing measuring light according to the present invention.

In <FIG> and <FIG> and <FIG> it is also shown illuminating or imaging optics <NUM> that does not belong to the depicted embodiments of the lighting assembly but can be incorporated into a measuring device using measuring light provided by the lighting assembly according to the embodiments. The imaging optics <NUM> can include a number of lenses and/or other optical components.

<FIG> shows that the assembly <NUM> includes an aperture component <NUM> comprising at least one orifice <NUM> and a first and opposite second side, a photoluminescent component <NUM>, and at least one pump light source <NUM> located on the first side of the aperture component <NUM>. One side of the photoluminescent component <NUM> is towards the second side of the aperture component <NUM>. The pump light source <NUM> is configured to emit pump light <NUM> and is disposed with respect to the first side of the aperture component <NUM> such that the pump light <NUM> can be directed from the pump light source <NUM> to the luminescent component <NUM> such that the pump light <NUM> passes through the orifice <NUM> of the aperture component <NUM>. In other words, the pump light <NUM> is allowed to enter the luminescent component <NUM> through the at least orifice <NUM> of the aperture component <NUM>.

When the pump light <NUM> that comprises a first wavelength enters the luminescent component <NUM>, the luminescent component <NUM> converts the pump light (or at least part of it) into polychromatic light measuring light <NUM>. The polychromatic measuring light <NUM> can comprise a spectrum of wavelengths, which are typically greater than the wavelength of the pump light <NUM>. Part of the polychromatic measuring light <NUM> passes through the at least one orifice <NUM> to the first side of the aperture component <NUM>. The pump light source <NUM> and the imaging optics <NUM> of the measuring device utilising the measuring light <NUM> provided to the first side of the aperture component <NUM> can be disposed with respect to the at least one orifice <NUM> such that the measuring light <NUM> passed through the at least one orifice <NUM> is collectable by the imaging optics <NUM>, as shown in the figure. The collected measuring light <NUM> can be further focusable by the imaging optics <NUM> or other optics of the measuring device onto an object being illuminated (not shown in the figure).

The pump light source <NUM> can comprise a laser or an LED configured for providing pump light characterised in wavelength that causes a desired conversion of the pump light <NUM> (by e.g., phosphorescence or fluorescence process, depending on the embodiment) into the measuring light <NUM> in the photoluminescent component <NUM>. The pump light is typically nearly monochromatic.

The pump light <NUM> and the measuring light <NUM> can be arranged to pass through the same the at least one orifice <NUM> of the aperture component <NUM>, the pump light from the first side and the measuring light from the second side of the aperture component, respectively.

The lighting assembly can comprise a plurality of pump light sources <NUM>. For instance, in cases where the aperture component <NUM> comprises a plurality of orifices <NUM> there can be a plurality of pump light sources <NUM> to direct pump light <NUM> to the luminescent component <NUM> through the plurality of orifices <NUM>, and therefore, to provide measuring light <NUM> from the plurality of orifices <NUM>.

In one embodiment, a plurality of pump light sources <NUM> is arranged to illuminate pump light <NUM> through the same at least one slit-shaped orifice <NUM> or a group of point-formed orifice <NUM> to increase luminous energy and/or radiant energy per unit are on the luminescent component <NUM> behind the orifice <NUM>, and hence, intensity and/or radiance of the pump light <NUM> passed through the corresponding orifice <NUM>. In one embodiment, a first number of pump light sources <NUM> is configured to direct pump light <NUM> to a first number of orifices <NUM> and a second or further number of pump light sources <NUM> is configured to direct pump light <NUM> to a second or further number of orifices <NUM>, respectively. In this embodiment, the orifice through which converted measuring light <NUM> is provided, and hence, the position wherefrom the aperture component <NUM> the measuring light <NUM> is provided can be modulated by modulating the pump light sources being configured to direct the pump light to the different orifices <NUM>.

Each orifice <NUM> can be a punctiform orifice or slit-shaped orifice. In this context by the slit-shaped orifice is meant a long, narrow cut or opening that can be formed into a straight or curved shape in the aperture component <NUM>.

Practically, the orifice <NUM> is configured to define and give the measuring light <NUM> passed through the orifice <NUM> essentially in a form or shape of the orifice <NUM>. The slit-shaped orifice <NUM> can be e.g., <NUM> wide and <NUM> long opening in the aperture component. A person skilled in the art shall appreciate the fact that such dimensions of the orifice <NUM> can indeed vary embodiment-specifically.

According to the invention, the aperture component <NUM> comprises a plurality of punctiform orifices and/or at least one slit-shaped orifice. The punctiform orifices can be arranged into a line or other formation.

<FIG> illustrates the directing of pump light <NUM> from the pump light source <NUM> of the lighting assembly <NUM> (for reasons of the clarity measuring light <NUM> is not shown in the figure). In <FIG> it is shown that an illumination area or spot of the pump light <NUM> from an individual pump light source <NUM> covers at least the shape of the orifice <NUM>. Therefore, the pump light source <NUM> can comprise optics and/or the pump light source <NUM> can be disposed such that the pump light source <NUM> can create a tightly focused and homogenous illumination spot of the pump light <NUM> which covers the whole area of the orifice <NUM>. However, in order to increase efficiency of the lighting, it is advantageous to create this illumination spot in a such way that a very minor part of the pump light <NUM> hits the surface of the aperture component <NUM> and a most part of the pump light <NUM> enters directly the luminescent component <NUM> through the orifice.

When the pump light <NUM> from at least one pump light source <NUM> is directed to the aperture component <NUM> and the at least one orifice <NUM> therein, part of the pump light <NUM> may reflect from the edges of the at least one orifice <NUM> or from a surface of the first side of the aperture component <NUM>. However, a person skilled in the art shall appreciate the fact that such reflected pump light <NUM> can be removed e.g., by filtering means to prevent entering of the reflected pump light <NUM> to an object being illuminated by the measuring light <NUM>.

<FIG> illustrates the passing of the measuring light <NUM> through the orifice <NUM> (for reasons of the clarity the pump light source <NUM> is not shown in the figure). In the figure there is a gap between the aperture component <NUM> and the luminescent component <NUM> just to show that the imaging optics <NUM> of the measuring device utilising the measuring light <NUM> collects the measuring light <NUM> through the orifice <NUM> from larger area of the fluorescent material <NUM> behind the orifice <NUM> than the area of the orifice <NUM>. Therefore, in order to increase efficiency of the lighting assembly, it is advantageous to dispose the luminescent component <NUM> directly contact with aperture component <NUM> and form the aperture component <NUM> as thin as possible.

Since the orifice <NUM> can be placed very close to the photoluminescent component <NUM> and to the at least one orifice <NUM> therein, the orifice <NUM> defines essentially the shape of the emitting area of the measuring light <NUM>, which practically corresponds to the shape of the orifice <NUM>. This allows to maximise efficiency of the assembly and intensity of measuring light <NUM> provided through the orifice <NUM>.

<FIG> shows at <NUM> a variation of the lighting assembly that differs from the embodiment <NUM> of <FIG> in that it includes a substrate component <NUM> attached to a side of the photoluminescent component <NUM> opposite to another side of the photoluminescent component <NUM> towards the orifice <NUM> and the second side of the aperture component <NUM>.

The substrate component <NUM> can support the photoluminescent component <NUM>. It <NUM> can be e.g., a metal, such as copper, substrate, and enables a positioning of the photoluminescent component <NUM> and its efficient cooling when illuminated (i.e. irradiated) by the pump light <NUM>.

The aperture component <NUM>, the photoluminescent component <NUM> and the substrate component <NUM> can be connected each other such that the photoluminescent component <NUM> is at least partially sandwiched between the substrate component, as shown in <FIG>.

<FIG> illustrate embodiments of the aperture component <NUM>.

In <FIG> is shown an aperture component <NUM> that can be a piece, preferably thin layer or film, of nontransparent material such as metal comprising at least one orifice <NUM>. As motivated hereinabove, the aperture component <NUM> is advantageously attached directly on the surface of the luminescent component <NUM>. The aperture component <NUM> can be attached to the luminescent component <NUM> such that there is an adhesive layer or the like between the aperture component <NUM> and the luminescent component <NUM>.

<FIG> illustrates a further embodiment of the aperture component <NUM>. The shown design incorporates an optically transmissive substrate <NUM>. In this design the transmissive substrate <NUM> is a layer that is transmissive for the pump light <NUM> and the measuring light <NUM> as well, wherein the aperture component is a masking, preferably a thin film of metal or other material, layer on a side of the transmissive substrate <NUM> towards the luminescent component <NUM>, as shown in <FIG>. The masking layer comprising at least one orifice <NUM> can be formed directly on the surface of the transmissive substrate <NUM> by deposition process, for example. This design allows forming of the aperture component <NUM> (i.e., the masking layer) and the at least one orifice <NUM> thereon can be formed very thin.

Alternatively, the aperture component <NUM> can be formed on other side of the substrate <NUM> opposite the side towards the luminescent component <NUM>. However, this is not preferred since there is in this case the substrate <NUM> between the aperture component <NUM> and the luminescent component <NUM> which reduces efficiency of the illumination of the pump light <NUM> per unit area on the luminescent component <NUM> and intensity of the measuring light <NUM> provided through the orifice <NUM>.

<FIG> illustrates a further embodiment of the aperture component <NUM>. In this design the aperture component <NUM> comprises a masking, preferably metal or other material, layer that is formed e.g., by deposition process directly on the surface of the photoluminescent component <NUM>. This design has the advantage that the aperture component <NUM> (i.e., the masking) and the at least one orifice <NUM> therein can be formed very thin and essentially to the level of the surface of the photoluminescent component <NUM>.

<FIG> illustrates a further embodiment of the aperture component <NUM>. In this design the luminescent component <NUM> extends to and fill the orifice <NUM> of the aperture component <NUM>. The luminescent component <NUM> and the first surface of the aperture component are hence essentially at the same level, i.e., the thickness of the aperture component is practically nil. This design can be manufactured by compressing the powder material of the luminescent component <NUM> to the orifice <NUM> or machining either the luminescent component <NUM> or aperture component <NUM> or both, for example.

In a further embodiment, the material of the aperture component <NUM> is configured to be transparent for the pump light <NUM> and nontransparent for the measuring light <NUM>. This design allows using essentially all pump light <NUM> for illuminating the luminescent component <NUM> and hence increasing the light conversion efficiency into measuring light <NUM> and its intensity.

In a further embodiment, the second side of the aperture component <NUM> is configured to be at least partially reflectable for the pump light <NUM> and/or the measuring light <NUM>.

<FIG> illustrate further variations of the lighting assembly.

In <FIG> is shown a lighting assembly <NUM> that comprises a plurality of pump light sources <NUM>. The pump light sources <NUM> can be disposed such that pump light <NUM> is directed from different locations and angles to the orifice <NUM>, as shown in the figure. By irradiating the photoluminescent component <NUM> by the plurality of pump light sources <NUM> it is possible to further increase pump light <NUM> per unit area on the luminescent component, and hence, increase light conversion from the pump light <NUM> into measuring light <NUM> and intensity of measuring light <NUM>.

<FIG> shows a lighting assembly <NUM> that differs from the lighting assembly <NUM> in that it further includes an optical connecting component <NUM>. The connecting component <NUM> is disposed on the first side of the aperture component <NUM> such that the pump light <NUM> from the pump light source <NUM> is inputtable and directable via the connecting component <NUM> to the at least one orifice <NUM>.

The connecting component <NUM> can be a beam splitter or dichroic filter disposed on the first side of the aperture component <NUM> such that the pump light <NUM> from a pump light source <NUM> is reflectable from (i.e., via) the beam splitter <NUM> to the orifice <NUM> being further entered the photoluminescent component <NUM> behind the aperture component <NUM> and that the measuring light <NUM> emitted from the luminescent component <NUM> is transmissible through the connecting component <NUM>.

Alternatively, the connecting component <NUM> can be a mirror or optical fiber disposed such that it <NUM> does not block propagating of the measuring light <NUM>.

<FIG> shows a lighting assembly <NUM> that differs from assembly <NUM> in that the pump light source <NUM> and the optical connecting component <NUM> are configured to provide the pump light <NUM> inside the measuring device utilising measuring light. In this design the pump light source <NUM>, the connecting component <NUM> and the imaging optics <NUM> are disposed in relation to the at least one orifice <NUM> such that the pump light <NUM> from the pump light source <NUM> is inputtable and directable via the connection component <NUM> and further through the imaging optics <NUM>, wherein the imaging optics is configured to focus the pump light <NUM> through the imaging optics <NUM> to the at least one orifice <NUM>, and wherein the measuring light <NUM> passed through the at least one orifice <NUM> is collectable by the imaging optics <NUM>. In this design there is not necessarily need to incorporate optics to the pump light source <NUM>. However, in the cases where there are optics incorporated in the pump light source <NUM> an illumination spot of the pump light <NUM> can be formed by a combination of the imaging optics <NUM> and the optics of the pump light source <NUM>. In the design of <FIG> the imaging optics <NUM> of the measuring device can be used for collecting and focusing the pump light <NUM> from the at least one pump source <NUM> to the luminescent component <NUM> and for collecting the measuring light <NUM> passed through the at least orifice <NUM> which can be further be focusable via the imaging optics onto an object being illuminated. This is a clear advantage which cannot be actualised with the conventional lighting assembly where the pump light and the measuring light are not allowed to pass through the same orifice.

As described hereinabove the lighting assembly according to the present invention is incorporated into a chromatic confocal measuring device for providing measuring light <NUM> for the chromatic confocal measuring device.

Generally, the lighting assembly according to the present invention and disclosure can utilise reflection luminescence in the conversion of pump light <NUM> into measuring light <NUM> in the luminescent component <NUM> for providing measuring light <NUM>.

The lighting assembly according to the present invention can be incorporated into a chromatic confocal measuring device such as disclosed e.g., in patent publications <CIT> or <CIT>.

<FIG> includes a flow diagram <NUM> disclosing an embodiment of a method in accordance with the present invention. The method comprises the following actions:.

In a method according to an embodiment, the pump light <NUM> and the measuring light <NUM> can be arranged to pass through the same the at least one orifice <NUM> of the aperture component <NUM>.

In a method according to an embodiment, the material of the aperture component <NUM> can be transparent for the pump light <NUM> and nontransparent for the measuring light <NUM>.

In a method according to an embodiment, the second side of the aperture component <NUM> can be at least partially reflectable for the pump light <NUM> and/or the measuring light <NUM>.

In a method according to an embodiment, the lighting assembly can further comprise a substrate component <NUM> attached to a side of the photoluminescent component <NUM> opposite to another side of the photoluminescent component <NUM> towards the second side of the aperture component <NUM>.

In a method according to an embodiment, the aperture component <NUM>, the photoluminescent component <NUM> and the substrate component <NUM> can be attached to each other forming a multilayer structure such that the photoluminescent component <NUM> is at least partially sandwiched between the substrate component <NUM> and the aperture component <NUM>.

In a method according to an embodiment, the assembly can further comprise a connecting component <NUM> disposed on the first side of the aperture component such that the pump light <NUM> is inputtable via the connecting component to the at least one orifice <NUM>.

In a method according to an embodiment, the connecting component <NUM> can be a beam splitter or dichroic filter, wherein the measuring light <NUM> being allowed to pass through the connection component <NUM>.

In a method according to an embodiment, the connection component <NUM> can be a mirror or optical fiber.

According to the invention, the at least one orifice <NUM> comprises a plurality of punctiform orifices or a slit-shaped orifice.

In a method according to an embodiment, the aperture component <NUM> can comprise a masking, preferably metal film, layer on the photoluminescent component <NUM>, being preferably produced by deposition technology.

In a method according to an embodiment, the lighting assembly can further comprise an optically transmissive substrate <NUM> located on the first side of the aperture component <NUM>, wherein the aperture component comprises a masking, preferably metal film, layer on a side of the transmissive substrate <NUM> towards the luminescent component <NUM>. The masking is preferably produced by deposition technology.

The invention has been explained above with reference to the aforementioned embodiments, and several advantages of the invention have been demonstrated. It is clear that the invention is not restricted to these embodiments but only by the scope of the claims.

Claim 1:
A chromatic confocal measuring device for determining one or more properties of a surface of an object, the measuring device comprising a lighting assembly, which comprises:
- an aperture component (<NUM>) comprising a first and opposite second side and at least one orifice (<NUM>);
- at least one pump light source (<NUM>) to provide pump light (<NUM>); and
- photoluminescent component (<NUM>) located on the second side of the aperture component (<NUM>) for converting pump light (<NUM>) receivable through the at least one orifice (<NUM>) onto the photoluminescent component (<NUM>) from the at least one pump light source (<NUM>) into polychromatic measuring light (<NUM>),
wherein part of the measuring light (<NUM>) is allowed to pass the aperture component (<NUM>) through the at least one orifice (<NUM>) to provide measuring light (<NUM>) to the first side of the aperture component (<NUM>),
wherein the pump light source (<NUM>) being located on the first side of the aperture component (<NUM>), and
wherein the at least one orifice comprises a slit-shaped orifice or a plurality of punctiform orifices.