EP0250191A2 - Réflecteur pour lampes à réflecteur - Google Patents

Réflecteur pour lampes à réflecteur Download PDF

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Publication number
EP0250191A2
EP0250191A2 EP19870305285 EP87305285A EP0250191A2 EP 0250191 A2 EP0250191 A2 EP 0250191A2 EP 19870305285 EP19870305285 EP 19870305285 EP 87305285 A EP87305285 A EP 87305285A EP 0250191 A2 EP0250191 A2 EP 0250191A2
Authority
EP
European Patent Office
Prior art keywords
facets
reflector
facet
lamp reflector
lamp
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19870305285
Other languages
German (de)
English (en)
Inventor
Anthony Leonard Isaacs
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thorn EMI PLC
Original Assignee
Thorn EMI PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thorn EMI PLC filed Critical Thorn EMI PLC
Publication of EP0250191A2 publication Critical patent/EP0250191A2/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V7/00—Reflectors for light sources
    • F21V7/04—Optical design
    • F21V7/09—Optical design with a combination of different curvatures

Definitions

  • the present invention relates to reflectors of the kind commonly used with pre-focussed reflector lamps in particular, but not solely, low voltage tungsten halogen lamps.
  • Reflectors of this kind are usually parabolic or elliptical in shape and, as is well known in the art, are often faceted.
  • One purpose of this faceting is to prevent imaging of the lamp filament from distorting what would otherwise be a reasonably uniform illumination.
  • hexagonal/diamond shaped facets Conventionally, these facets have been rectangular in shape, but we have also advantageously used hexagonal/diamond shaped facets.
  • the hexagonal/diamond pattern is derived from a pattern of intersecting curved shapes which are, to a first mathematical approximation, ellipses.
  • the pattern is first created on a mould from which the reflectors are then made. Each grinding into the surface of the mould produces, to a first mathematical approximation, an ellipse.
  • These ellipses form circular and radial patterns of ellipses and it is the intersection of the ellipses which are not on the same radial or circular bands which give the final hexagonal/diamond pattern.
  • each hexagonal/diamond shaped facet forms a dimple in the surface of the reflector; the depth of the dimple being defined as the normal deviation of the centre of the facet from the original surface.
  • a lamp reflector suitable for a prefocussed lamp, the lamp reflector having a surface which is partially covered with facets there being a region of unfacetted surface between a facet and at least one of its immediate neighbours.
  • the said facets may be derived from shapes which are, to a first mathematical approximation, ellipsoidal.
  • the ellipsoidal shapes either touch, do not touch at all or intersect such that the resulting facets respectively touch at a point, do not touch at all or touch at a line to leave some of the original surface between some or all of the facets; the original surface being defined as the surface of the reflector as it was before being faceted.
  • the resulting surface conforms more closely to the original surface than do those surfaces obtained using the prior art techniques; it is therefore less distorted and so gives less scattering of the light from the filament, while still having the desired effect of defocussing the filament.
  • the facets come into contact with each other, but do not intersect, resulting in a pattern of facets each having a perimeter which, to a first mathematical approximation, is an ellipse, with the spaces between the facets comprising the original surface.
  • the facets may be offset or alternatively, they can be in line.
  • each band or row of facets is, in general, progressively more shallow than the preceding band or row as the pole of the reflector is approached, the depth of a facet being defined as the normal deviation of the centre of the facet from the original surface.
  • the depth of the facets can become so shallow as to be insignificant and this tends to make manufacture of these facets difficult.
  • faceting may cease at a point where manufacture has become difficult or, preferably, an increased facet depth can be used by reducing the number of facets in the row or rows closest to the pole of the reflector.
  • a preferred reduction in the number of facets is in the ratio of 2:1, which leaves the overall facet pattern uniform.
  • the aforementioned near ellipses do not come into contact with each other at all, giving the reflector a surface which is covered with non-touching near elliptically shaped facets; where the areas between the facets are parts of the original, undistorted surface.
  • the near ellipses do intersect, but not sufficiently to remove completely the original undistorted surface between some or all of them.
  • Figure 1 is a schematic front view of the hexagonal/diamond faceted reflector already known in the art.
  • Figure 2 shows the pattern of intersecting curved shapes which are, to a first mathematical approximation ellipses and which, although themselves not visible on the finished article, create the hexagonal/diamond faceted pattern shown in Figure 1.
  • Comparison of Figures 1 and 2 shows quite clearly how the desired effect is achieved.
  • the facet pattern depicted in Figure 3 represents a preferred embodiment of the invention.
  • the curved shapes which are ellipses to a first mathematical approximation, come into contact with each other, but substantially do not intersect and the spaces between them are the original surface of the reflector. Because the ellipses used to form this facet pattern do not intersect, they can be made smaller than the necessarily intersecting ellipses which are used to create the known hexagonal/diamond facet pattern.
  • the dimples in the original surface formed by these elliptically shaped facets are not as deep as those formed by the hexagonal/diamond facets; that is, the normal deviation of the centre of the facet from the original surface is not as great.
  • the elliptically faceted surface of the reflector as shown in Figure 3, more closely resembles the original surface than does the hexagonal/diamond faceted surface of the prior art and so cause less scattering of the light from the lamp; while at the same time still having the desired effect of defocussing the lamp filament.
  • the facets are shown offset, but the desired effect can equally well be obtained if the facets are in line.
  • Figure 4 shows an alternative embodiment of the invention which allows the facet depth to be increased by reducing the number of facets from that row onwards.
  • the reduction of the number of facets in each row is in the ration of 2:1, which leaves the overall facet pattern uniform.
  • a different ratio may be desired.
  • the invention described herein provides a faceted reflector preferably, though not necessarily, for use with a pre-focussed reflector lamp; which achieves the desired effect of defocussing the filament of the lamp but, as a result of reduced surface distortion, gives less scattering of the light from the lamp than is normally associated with faceted lamp reflectors of the kind known in the art.
  • the invention has the additional advantage that existing manufacturing techniques may be used for its production.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
  • Optical Elements Other Than Lenses (AREA)
EP19870305285 1986-06-19 1987-06-15 Réflecteur pour lampes à réflecteur Withdrawn EP0250191A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB868614988A GB8614988D0 (en) 1986-06-19 1986-06-19 Reflector
GB8614988 1986-06-19

Publications (1)

Publication Number Publication Date
EP0250191A2 true EP0250191A2 (fr) 1987-12-23

Family

ID=10599738

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19870305285 Withdrawn EP0250191A2 (fr) 1986-06-19 1987-06-15 Réflecteur pour lampes à réflecteur

Country Status (2)

Country Link
EP (1) EP0250191A2 (fr)
GB (1) GB8614988D0 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0985870A2 (fr) * 1998-09-11 2000-03-15 Osram Sylvania Inc. Lampe avec réflecteur à facettes et lentille en spirale
DE19910192A1 (de) * 1999-03-09 2000-09-21 Schott Auer Gmbh Optisches Design für einen Reflektor zum Reflektieren von Lichtstrahlen
EP0950850A3 (fr) * 1998-04-15 2001-04-18 Matsushita Electronics Corporation Unité d'éclairage avec miroir réfléchissant
US7025476B2 (en) * 2003-04-25 2006-04-11 Acuity Brands, Inc. Prismatic reflectors with a plurality of curved surfaces
EP1890079A1 (fr) * 2006-08-15 2008-02-20 Schott AG Réflecteur pour lampes à décharge

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0950850A3 (fr) * 1998-04-15 2001-04-18 Matsushita Electronics Corporation Unité d'éclairage avec miroir réfléchissant
US6369492B1 (en) 1998-04-15 2002-04-09 Matsushita Electronics Corporation Lighting unit with reflecting mirror
EP0985870A2 (fr) * 1998-09-11 2000-03-15 Osram Sylvania Inc. Lampe avec réflecteur à facettes et lentille en spirale
EP0985870A3 (fr) * 1998-09-11 2001-11-14 Osram Sylvania Inc. Lampe avec réflecteur à facettes et lentille en spirale
DE19910192A1 (de) * 1999-03-09 2000-09-21 Schott Auer Gmbh Optisches Design für einen Reflektor zum Reflektieren von Lichtstrahlen
US6361175B1 (en) 1999-03-09 2002-03-26 Schott Auer Gmbh Optical design for a reflector for reflecting light beams
DE19910192C2 (de) * 1999-03-09 2002-04-04 Schott Auer Gmbh Reflektor mit einem konkaven rotationssymmetrischen Grundkörper und einer Facetten aufweisenden Reflexionsfläche
US7025476B2 (en) * 2003-04-25 2006-04-11 Acuity Brands, Inc. Prismatic reflectors with a plurality of curved surfaces
EP1890079A1 (fr) * 2006-08-15 2008-02-20 Schott AG Réflecteur pour lampes à décharge
US7832905B2 (en) 2006-08-15 2010-11-16 Auer Lighting Gmbh Reflector for gas discharge lamps

Also Published As

Publication number Publication date
GB8614988D0 (en) 1986-07-23

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Inventor name: ISAACS, ANTHONY LEONARD