EP2428727B1 - Light reflector and method and device for its manufacture - Google Patents

Description

The present invention initially relates, according to the preamble of claim 1, to a luminaire reflector consisting of a hollow, cup-shaped, in particular rotationally symmetrical, paraboloidal reflector body having an inner reflection surface and having a rear, smaller illuminant opening and a front in the direction of its longitudinal center axis the larger the light exit opening increasing inner diameter, wherein the reflection surface is divided into a plurality of structured facets, each having a curved at least in a surface direction with a radius of curvature facet surface, and wherein the facets in a grid-like structure on the one hand in the circumferential direction in concentric ring groups and on the other hand in radially symmetrical arranged between the lamp opening and the light exit opening arranged column groups.

Furthermore, the invention according to the preamble of claim 8 also relates to a device for producing such a luminaire reflector, consisting of a molded press body with an inside of the produced reflector body adapted negative contour with corresponding facet negative surfaces, the facet negative surfaces in a grid-like structure on the one hand are arranged in the circumferential direction in concentric ring groups and on the other hand in radially symmetric column groups.

A luminaire with a reflector element of the generic type is in the EP 1 632 713 B1 described. Due to the two-dimensional, in particular spherically curved surfaces of the individual facets - there called "segments" - a scattering (fanning) to equalize the light emitted by a lamp for a more homogeneous illumination is to be achieved. Specifically, it is intended that the radii of curvature of the segments between an inner vertex area of the reflector element and the outer light exit opening should also increase with increasing distance from the vertex area. The known reflector element should preferably consist of pressed aluminum, wherein an aluminum disk, that is a circular disk, is moved along a rotating pin (press molded body), so that the pin (male) is imaged in the aluminum blank. However, experience has shown that this production by forming in the spinning process has the disadvantage of very large manufacturing tolerances. In particular in the area of the individual facets, large deviations between the actual desired curvature radii on the one hand and curvature radii on the finished pressed reflector body on the other hand are inevitably inevitable and therefore predetermined for the facet negative surfaces of the press molded body with reversed (negative) curvature. Therefore, it is at least questionable whether the radii increasing from the inside out according to EP 1 632 713 B1 in practice even feasible, ie reproducible produced in the pressing process.

The document EP 1 890 079 A1 describes a reflector, in particular for gas discharge lamps. Also, this known reflector is formed as a faceted reflector with a plurality of facets, which are arranged in radial and circular columns or rows and formed as cylindrical facets and / or spherical facets. The facets should be curved with radii which assume values of between 9.1 mm and 150 mm, wherein facets with the same radii in each case should be arranged in a spiral such that the facets within each column or row are periodically and in accordance with a sine curve. and lose weight. This means that the radii successively increase and decrease in each case over a plurality of facets lying one behind the other in a row / column, which in the case of the radial gaps is thus in regions of the prior art according to the aforementioned EP 1 632 713 B1 equivalent. However, in contrast to the reflector according to EP 1 890 079 A1 made of glass with a reflective coating. Therefore, this is not the previously discussed manufacturing problem. The present invention is based on the object to provide a luminaire reflector of the generic type described above, which ensures an optimal, homogeneous light emission largely independent of the manufacturing tolerances. In addition, a correspondingly optimized device for producing the reflector according to the invention is to be created.

This is achieved by a reflector having the features of the independent claim 1 or by a device according to claim 8. Advantageous embodiments are contained in the dependent claims.

Accordingly, the luminaire reflector according to the invention is characterized in that the facet surfaces at least within a partial area of at least 50% of the reflection surface - based on the radial and axial extent between the illuminant opening and the light exit opening - in terms of size of each at least one of its radii of curvature designed are that in each column group successive facets regularly between the adjacent directly adjacent facets alternately rising and falling or falling and again rising radii of curvature have. This means that the radii of curvature from inside to outside between individual directly adjacent facets become alternately larger and smaller or smaller and larger, depending on whether starting with a smaller or a larger radius. This results in each radii differences, which - analogous to a mathematical "alternating series" - alternately changing signs (+/-) have. So can from the inside out z. B. in each case a larger radius and a smaller radius alternate. According to the invention, it is thus a regularly changing radius-size profile between individual facets. However, the radii differences resulting from the alternately different radii can differ in their amounts from one another, so that they are qualitatively at least with a minimum value existing differences and not necessarily also quantitatively exactly defined differences.

In order to ensure the alternating radii differences also in the finished pressed reflector body, it is preferably provided in the device according to the invention that-at least within a corresponding subregion of at least 50% of the outer surface-two adjacent facets directly adjacent in each column group and different facets for their radii of curvature. Negative surfaces are designed such that the respective smaller radius of curvature is at least 25% smaller than the respective larger radius of curvature, d. H. the smaller radius corresponds to a maximum of 75% of the larger radius. If, for example, the larger radius should be 10 mm, the smaller radius with a maximum of 7.5 mm would be predefined. With this minimum difference of 25% can in the case of the device according to the invention, d. H. on the molded article according to the invention depressed reflector of the alternately increasing and decreasing radii profile can be reproducibly ensured.

From the curvature radii alternatingly changing their size according to the invention, a very good light uniformity results through a varying light scattering in the differently curved surface areas of the facets.

• Fig. 1 eine Ansicht in axialer Richtung in den Innenbereich eines erfindungsgemäßen Leuchten-Reflektors,
• Fig. 2 einen Axialschnitt in der diametralen Schnittebene II-II gemäß Fig. 1 in einer im inneren Bereich der Reflexionsfläche vereinfachten Darstellung,
• Fig. 3 eine schematische, vergrößerte Perspektivansicht im Bereich einer Facette in einer ersten Ausführung. d. h. in einer Mindestausführung mit nur einfacher Krümmung,
• Fig. 4 eine Ansicht analog zu Fig. 3 in einer bevorzugten Ausführung mit zweifacher Krümmung,
• Fig. 5 eine Perspektivansicht eines Beispiels eines Drückformkörpers zur Herstellung des Reflektors,
• Fig. 6 eine alternative Ausgestaltung des erfindungsgemäßen Reflektors in einer Axialansicht in den Innenbereich analog zu Fig. 1 und
• Fig. 7 eine axiale Draufsicht (entsprechend dem Ansichtsrichtungspfeil VII in Fig. 5) auf einen Drückformkörper für die Reflektor-Ausführung nach Fig. 6.

In the following description, the invention will be described in detail with reference to a preferred embodiment and some embodiments. Show it:

• Fig. 1 a view in the axial direction in the interior of a luminaire reflector according to the invention,
• Fig. 2 an axial section in the diametric section plane II-II according to Fig. 1 in a simplified in the inner region of the reflection surface representation,
• Fig. 3 a schematic, enlarged perspective view in the region of a facet in a first embodiment. ie in a minimum design with only a simple curvature,
• Fig. 4 a view analogous to Fig. 3 in a preferred embodiment with double curvature,
• Fig. 5 a perspective view of an example of a pressure-molded body for the production of the reflector,
• Fig. 6 an alternative embodiment of the reflector according to the invention in an axial view in the interior analogous to Fig. 1 and
• Fig. 7 an axial plan view (corresponding to the direction of view arrow VII in Fig. 5 ) on a molded article for the reflector design Fig. 6 ,

In the various figures, the same parts are always provided with the same reference numerals.

For the following description, it is expressly emphasized that the invention is not limited to the exemplary embodiments and not all or several features of described combinations of features, but each individual feature of the / each embodiment can also be separated from all other partial features described in connection therewith and also have an inventive meaning in combination with any features of another embodiment as well as independent of the claim back relationships.

An inventive luminaire reflector 1 consists of a hollow, cup-shaped arched reflector body 2 with an inner reflection surface 4. The reflector body 2 has a seen in the direction of a longitudinal central axis 6 of a rear, smaller bulb opening 8 in the radial and axial direction up to a front, larger light exit opening 10 increasing, each measured perpendicular to the longitudinal central axis 6 inner diameter. Preferably, the reflector body 2 is rotationally symmetrical parabolic. In the area of the illuminant opening 8, an illuminant, not shown, can be arranged such that the light emitted by it is radiated outwardly at least partially from the light exit opening 10 by reflection via the reflection surface 4. As a light source, a flat LED element can advantageously also be arranged in the plane of the illuminant opening 8 or parallel thereto.

At least a major part of the reflection surface 4 is subdivided into a plurality of structured facets 12, which in Fig. 2 are shown only partially for simplicity. Each facet 12 has an at least in a surface direction curved facet surface 14.

This will be on Fig. 3 reference is made, according to which the facet surface 14 is curved or curved in only one surface direction illustrated by a dash-dotted line of curvature X with a radius of curvature R1. The curvature line X runs with the same curvature R1 over the facet surface 14. This only single curved facet 12 can also be referred to as a cylindrical facet because it corresponds to the shape of a section of a cylindrical surface.

In the preferred embodiment according to Fig. 4 but is the facet surface 14 - in addition to the curvature in the surface direction X - curved in a second, illustrated by a dashed line of curvature Y surface direction, namely with a radius of curvature R2. The radii R1 and R2 may be the same or different. The curvature lines X, Y expediently extend perpendicularly to one another in each case in the center over the facet surface 14. The same radii R1 = R2 are spherical facets, the facet surfaces 14 being designed as Ball sections are formed and therefore can also be referred to as ball facets.

alternative to Fig. 3 In principle, the facet surface 14 can also be curved as a cylindrical facet only in the surface direction Y.

The facets 12 are in a grid-like, in particular spider-web-like grid structure - see in particular the axial view in Fig. 1 - On the one hand in the circumferential direction in concentric, with respect to the longitudinal central axis 6 coaxial ring groups A and on the other hand in the radial and axial direction in radially symmetric distributed over the circumference column groups B. Each column group B extends according to Fig. 1 at least partially between the inner bulb opening 8 and the outer light exit opening 10 and in the circumferential direction over an angle α, which is divided by the circumference of 360 ° divided by the number of column groups B. By this embodiment, each facet 12 is approximately trapezoidal in plan view (see Fig. 1 ). In addition, the first curvature line X preferably extends with the first curvature radius R1 of each facet surface 14 in a radial or diametrical plane defined by the longitudinal center axis 6. The second curvature line Y of each facet surface 14 extends with the second radius of curvature R2 in the circumferential direction of the reflector body 2 and thus in a plane perpendicular to the longitudinal central axis 6.

As already mentioned, the two radii of curvature R1, R2 of each facet surface 14 can be of different sizes. Preferably, however, the facet surfaces 14 are each spherically curved, wherein the two radii of curvature R1, R2 are the same size.

According to the invention, at least in a partial region of the reflection surface 4 of at least 50%, based on the axial and radial surface extension between the openings 8 and 10, it is provided that the facet surfaces 14 at least each have one of their radii of curvature R1 and / or R2 in terms of size are designed so that in the axial and radial direction between the bulb opening 8 and the light exit opening 10, ie within each column group B, the radii of curvature R1 and / or R2 between the individual, each directly adjacent facets 12 regularly have different sizes alternately. In principle, the radius difference can optionally relate to R1 and / or R2.

In a further preferred embodiment, the facet surfaces 14 of the reflector body 2 are convexly curved toward the interior in the direction of the longitudinal central axis 6.

The reflector 1 or the reflector body 2 is produced in one piece in a forming-pressing process from a first flat sheet metal blank by the sheet metal blank to form the structured reflection surface 4 with rotation about the longitudinal central axis 6 to an exemplary in Fig. 5 shown negative-pressure mold or male, ie a pressure-molded body 16 is pressed. The pressure-molded body 16 has a negative contour corresponding to the interior of the reflector body 2, wherein corresponding, preferably concavely curved, facet negative surfaces 18 are structured on its outer surface. Corresponding to the lattice network structure of the reflector body 2, the facet negative surfaces 18 of the pusher body 16 are also arranged in a spider web-like structure in the circumferential direction in concentric ring groups A 'and in the axial and radial direction in radially symmetric column groups B'.

According to the invention, the facet negative surfaces 18 of the molded article 16 are at least in a partial region of at least 50% of the surface extent in the radial and axial directions with respect to the size of at least one of their radii of curvature R1 'R2' designed such that the radii of curvature within each column group B 'regularly have alternately different sizes. In a preferred embodiment, in each case two radially adjacent and with respect to their radii of curvature different facet negative surfaces 18 are designed such that the respective smaller radius of curvature smaller by at least 25% each larger radius of curvature, so that the respective smaller radius is a maximum of 75% of the larger radius. Preferably, in this case, the facet negative surfaces 18 are formed within each ring group A 'with the same radii of curvature. In the case of the pressed reflector body 2 produced with this device, however, the radii within each circular ring group A 'can deviate from one another within the scope of the manufacturing tolerance.

At the in Fig. 1 and 2 illustrated embodiment, in the interior, adjacent to the bulb opening 8 region z. B. two ring groups with facets 12a be arranged with flat, flat facet surfaces. This is followed by ring groups A with radii R1.1 and R1.2 changing from group A to group A. In this case, the radius R1.1 can be larger and the radius R1.2 smaller. For example, the larger radius R1.1 is 27 mm and the smaller radius R1.2 is 19 mm.

Alternatively, for example, an embodiment may be provided, wherein the smaller radii are 10 mm and the larger radii 17 mm.

The statements are only to be understood as examples and do not limit the invention. In addition, because of the unavoidable manufacturing tolerance, the radii mentioned relate in particular to the spinning mold; the reflector body 2 may deviate from the radii mentioned.

• Zunächst wird der gefertigte Reflektorkörper 2 optisch dreidimensional vermessen, und zwar mit einem Messgerät, welches unter der Bezeichnung "ATOS III SO 4 M" von der Firma GOM mbH (Gesellschaft für optische Messtechnik mbH in Braunschweig) erhältlich ist. In der Ausführung SO (= small objects) ist dieses Gerät besonders zur Vermessung kleiner Objekte - und so auch für den erfindungsgemäßen Reflektor - geeignet. Es handelt sich um einen optischen 3D-Digitalisierer bzw. um eine 3D-Koordinatenmessmaschine, die durch optisches Einscannen dreidimensionale Messdaten eines Bauteils liefert. Das Messgerät basiert auf dem Triangulationsprinzip mit einem digitalen Stereo-Kamera-Aufbau. Anhand von Abbildungsgleichungen der Optiken werden für jeden Kamerapixel unabhängige 3D-Koordinaten automatisch berechnet. Dadurch werden nicht nur einzelne Punkte ermittelt, sondern es wird die ganze Bauteil-Geometrie in einer hochauflösenden Punktewolke erfasst. Das so erfasste Polygonnetz beschreibt präzise die Oberfläche und Geometrie des Bauteils. Daraus werden CAD-Daten erzeugt.

In addition, it must be expressly mentioned that because of the described material deformation in the pressing process, the facet curvatures can deviate in cross section from an ideal circular arc shape, so that they do not have continuous, uniform, uniform radii of curvature over the curvatures. Rather, it is more about different, irregularly curved with several different radii of curvature free-form surfaces for the radii of curvature can not be measured directly, but must be averaged by approximating a circular arc shape accordingly, then the To be able to determine the radius of curvature of the approximated circular arc. In practice, the radii of curvature are determined in particular as follows:

• First, the manufactured reflector body 2 is measured optically three-dimensional, with a measuring device, which is under the name "ATOS III SO 4 M" by the company GOM mbH (Society for optical metrology mbH in Braunschweig) is available. In the version SO (= small objects), this device is particularly suitable for measuring small objects - and thus also for the reflector according to the invention. It is an optical 3D digitizer or a 3D coordinate measuring machine that provides three-dimensional measurement data of a component by optical scanning. The meter is based on the triangulation principle with a digital stereo camera setup. Using imaging equations of the optics, independent 3D coordinates are automatically calculated for each camera pixel. As a result, not only individual points are determined, but the entire component geometry is recorded in a high-resolution point cloud. The polygonal mesh thus captured accurately describes the surface and geometry of the component. From this CAD data are generated.

1. a) Soll-Radius gemäß einem vorgegebenen 3D-CAD
2. b) Gemessene Facetten-Wölbungsform (Freiformfläche)
3. c) Ermittlung eines "Best-Fit-Radius" auf der gemäß b) gemessenen Wölbungsform

For measuring the reflector according to the invention, a cut is made in each case in particular in a column group B, in each case in particular in a column group B, on the basis of the generated CAD data in order to determine the respective radius R1. If R1 = R2, R2 does not need to be determined separately. In each facet cut, the device evaluates the following:

1. a) target radius according to a given 3D CAD
2. b) Measured facet-curvature shape (free-form surface)
3. c) Determination of a "best fit radius" on the curved shape measured according to b)

In step c), a so-called "best-fit approximation" of a circular arc line to the measured free-form curve is automatically carried out with the mentioned device-based on an implemented software. The "best fit circular arc" is approximated to the determined curve shape so that deviations on average for all curve areas are minimized. The radius of curvature of the so-called "best-fit arc" is set as the facet radius of curvature (eg, R1).

The invention is not limited to the illustrated and described embodiments, but also includes all the same in the context of the invention embodiments. Thus, in the example described so far Fig. 1 to 5 Although the column groups B and B 'have a radial orientation in one view in the axial direction, ie the facets 12 of the reflector body 2 lying in a common column group and thus correspondingly also the negative surfaces 18 of the molded article body 16 are in each case located with their center points a in the axial view radially extending straight line (see Fig. 1 and 5 ). However, the term "grid-like facet structure" includes, for example, also embodiments such as in 6 and 7 illustrated, wherein the individual ring groups A and A 'from group to group by one in each Fig. 6 With β ₁ to β ₁₂ drawn circumferential offset against each other are rotated about the axis 6, so that the column groups B and B 'in the axial view - see 6 and 7 - Slightly inclined from the inside to the outside relative to the respective radial straight line and / or -. B. slightly spiral-like - curved. The respective circumferential offset β ₁ to β ₁₂ may, for. B. in the range of 0 ° to ± 4 °, ie from group to group optionally by 0 ° to 4 ° in one of the two opposite circumferential directions.

Claims (10)

1. Luminaire reflector (1), comprising a hollow reflector body (2) curved in a bowl shape, having an inner reflective surface (4) and having an inner diameter which increases in a direction of its longitudinal central axis (6) between a rear, smaller lamp opening (8) and front, larger light exit opening (10), the reflective surface (4) being divided into a multiplicity of structured facets (12) which each have a facet surface (14) extending in a curved manner with a radius of curvature (R1/R2) at least in one surface direction (X and/or Y), and the facets (12) being arranged in a grid-like structure, on the one hand, in a circumferential direction in concentric ring groups (A) and, on the other hand, in radially symmetrically arranged column groups (B) extending radially and axially from the inside outwards between the lamp opening (8) and the light exit opening (10),
   characterised in that the facet surfaces (14) are designed, at least in a partial region of at least 50% of the reflective surface (4) with regard to the size of at least respectively one of their radii of curvature (R1 and/or R2), in such a manner that the facets (12) lying one behind the other from the inside outwards within each column group (B) have regularly between the individual directly adjacent facets (12) radii of curvature (R1 and/or R2) alternately rising and falling again or falling and rising again.
2. Luminaire reflector according to Claim 1,
   characterised in that the facet surfaces (14) are curved in two surface directions (X, Y) which are in particular perpendicular to one another and have respectively one radius of curvature (R1, R2).
3. Luminaire reflector according to Claim 2,
   characterised in that the facet surfaces (14) are each spherically curved, the two radii of curvature (R1, R2) of each facet surface (14) being of equal size.
4. Luminaire reflector according to Claim 2,
   characterised in that the two radii of curvature (R1, R2) of each facet surface (14) are of different size.
5. Luminaire reflector according to one of Claims 1 to 4,
   characterised in that the facet surfaces (14) are convexly curved towards the interior of the reflector body (2).
6. Luminaire reflector according to one of Claims 2 to 5,
   characterised in that a first line of curvature (X) of each facet surface (14) extends in an axial plane of the reflector body (2).
7. Luminaire reflector according to one of Claims 2 to 6,
   characterised in that a second line of curvature (Y) of each facet surface (14) extends in a circumferential direction of the reflector body (2).
8. Device for producing a luminaire reflector (1) according to one of Claims 1 to 7, comprising a spinning form (16) having a negative contour which is matched to the interior of the reflector body (2) to be produced and has corresponding facet negative surfaces (18), the facet negative surfaces (18) being arranged in a grid-like structure, on the one hand, in a circumferential direction in concentric ring groups (A') and, on the other hand, in radially symmetrical column groups (B') extending radially and axially from the inside outwards,
   characterised in that the facet negative surfaces (18) are designed, at least in a partial region of at least 50% of the outer surface of the spinning form (16) with regard to the size of at least respectively one of their radii of curvature (R1' and/or R2'), in such a manner that the facet negative surfaces (18) lying one behind the other from the inside outwards in each column group (B') have regularly between the individual directly adjacent facet negative surfaces (18) radii of curvature (R1' and/or R2') alternately rising and falling again or falling and rising again
9. Device according to Claim 8,
   characterised in that respectively two directly adjacent facet negative surfaces (18) which differ with respect to their radii of curvature are designed in such a manner that the respectively smaller radius of curvature is at least 25% smaller than the respectively larger radius of curvature.
10. Device according to Claim 8 or 9,
    characterised in that the facet negative surfaces (18) within each ring group (A') have equal radii of curvature (R1' and/or R2').

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