EP0619006B1

EP0619006B1 - Reflector for an electrical radiation fitting and radiation fitting furnished with such a reflector

Info

Publication number: EP0619006B1
Application number: EP92924999A
Authority: EP
Inventors: Nils Svendenius
Original assignee: Fagerhults Belysning AB
Current assignee: Fagerhults Belysning AB
Priority date: 1991-12-09
Filing date: 1992-12-07
Publication date: 1999-03-10
Anticipated expiration: 2012-12-07
Also published as: WO1993012376A1; SE9103631L; DE69228614D1; ATE177521T1; DE69228614T2; EP0619006A1; SE9103631D0; SE469804B; AU3121293A

Abstract

The invention concerns a reflector (1) for an electrical radiation fitting (31) as well as a radiation fitting provided with one or several such reflectors. A reflector comprises top sections (3, 4) and with respect to the longitudinal extension of the fitting longitudinal sections (5, 6). The interior side of the reflector is provided with a reflecting layer (2). According to the invention, to the top section (3, 4) and the longitudinal sections (5, 6) there are connected at an angle of app. 45 DEG oblique diagonal sections (7-10) for controlling the light from a fluorescent tube (13) mainly in diagonal and longitudinal direction of the fitting. Between a pair of diagonal sections (7, 10) respectively (8, 9) there extends in transverse direction of the fitting transverse sections (11, 12), above which there are triangle-shaped openings for introduction of a fluorescent tube (13). The radiation fitting (31) is provided with a larger number of reflectors arranged in series, the lateral outer sides of which are situated within vertical planes for flush abutment against each other, the free edges of the sections being provided to rest upon a border (32) surrounding the fitting.

Description

The present invention refers to a reflector for an electrical radiation fitting and an electrical radiation fitting furnished with such a reflector.
The spread of light in longitudinal direction of the normally elongated conventional fluorescent tube fittings has so far been very unsatisfactory both concerning uniformity and primarily controllability. This has resulted in that the location of the light fittings has been directly crucial for the spread of light. The manufacturer has not to any significant effect been able to take into account needs and requests of the user in these respects. The result has been, that a certain surplus capacity and/or anti-dazzle-screens had to be used for accomplishing greater spread and uniformity. This is, of course, a disadvantage with respect to both illumination ergonomics and energy used. Previous attempts to satisfy various demands and requests have often entailed use of light fittings of different dimensions and/or shaped in different ways.
Furthermore, the previously known reflectors are relatively weak and/or material demanding. Also, it is often necessary to furnish the reflectors with special fasteners for keeping them in place in a light fitting.
By US-A-2 242 590, there is previously known a generally quadratic light reflector showing a top section, diagonal sections and sections interconnecting the diagonal sections. All the sections are flat or planar and are substantially uniformly shaped and arranged in mainly uniform spreading of light in all directions.
An objective of the invention is to improve and develop known techniques in this field primarily in the above mentioned respects. More precisely, the invention is to make possible a considerable, flexible light control even in longitudinal direction of an electric radiation fitting. It should even be possible, with use of a certain given fitting shell, by arranging differently shaped reflectors in said shell, to accomplish different light spread patterns, primarily in longitudinal direction of the fitting with maintained light spread in transverse direction of the fitting.
These objectives are accomplished according to the invention by a reflector of the initially defined kind, which reflector mainly is shaped as stated in the characterizing clause of claim 1. Said objectives are accomplished even in that an electric radiation fitting mainly is designed as stated in the first claim concerning such a fitting.
Further characteristics of and advantages with the invention are revealed by the following description with reference to the accompanying drawings, which show a preferred but not limiting embodiment of a reflector and a radiation fitting according to the invention, respectively. In detail, in the drawings there represent:

Fig. 1: a perspective view from above of a reflector according to the invention,
Fig. 2: a top plan view of a reflector according to fig. 1,
Fig. 3: an underneath plan view of the reflector according to fig. 1,
Fig. 4: a side elevational view of the reflector according to fig. 1,
Fig. 5: a diagrammatical sectional view along line A - A in fig. 1,
Fig. 6: a diagrammatical sectional view along line B - B in fig. 1,
Fig. 7: a diagrammatical sectional view along ling C - C in fig. 1,
Fig. 8: a perspective view of several reflectors according to fig. 1 arranged in series in longitudinal direction on a fluorescent tube,
Fig. 9: a perspective view of a radiation fitting furnished with reflectors according to the invention,
Fig. 10: main radiation from a reflector according to the invention with the reflector shown in an underneath plan view,
Fig. 11: a diagram illustrating the distribution of light in transverse and longitudinal direction of a conventional fluorescent tube fitting,
Fig. 12: a diagram illustrating the distribution of light in transverse and longitudinal direction of a corresponding fluorescent tube fitting which, however, is furnished with reflectors according to the invention, and
Fig. 13: a diagram corresponding to fig. 12 showing the distribution of light in the two diagonal directions right between longitudinal and transverse direction.

A reflector according to the invention is designated in the drawings by 1 in its entirety and may consist of either a homogeneous body of metal and/or plastic material and/or glass and/or ceramics or several loose segments which together, preferably assembled, e.g. glued or welded together form a structure of e.g. a kind as shown in the drawings. Such a reflector is, at least on its interior side, provided with a reflecting layer 2 of e.g. aluminum. The reflector or its parts, respectively, may be produced by compression molding, injection molding, casting, deep drawing and similar manufacturing methods as known per se. Similarly, application of layer 2 is known per se, e.g. by adhesion, evaporation, anodization etc, unless the material of the reflector per se offers a reflecting layer which, e.g. by polishing, can be made more efficient as to its reflecting properties.
The reflector design as shown in the drawings shows two top sections 3 and 4, two longitudinal sections 5 and 6 connected thereto, four diagonal sections 7 - 10 connected to both said top sections and said longitudinal sections, as well as transverse section 11 and 12, which mainly connect with their ends to a pair of diagonal sections. The terms "transverse", "diagonal" and "longitudinal" have been chosen with respect to the longitudinal extension of an elongated radiation fitting. Consequently, the longitudinal sections reflect radiation mainly laterally from the fitting, the transverse sections in longitudinal direction of the fitting and the diagonal sections both in transverse and longitudinal direction. Apart from direct radiation from a light source 13, particularly one or several fluorescent tubes, there occurs once reflected radiation, i.e. radiation which, after leaving the light or radiation source, impacts one of the said sections and is then reflected away from the reflector, as well as multiply reflected radiation, where radiation travels between at least two sections, before it leaves the reflector.
The sectional view according to fig. 5 is entirely symmetrical with respect to the axis H. The cross section may consist of the involution 14 of a circle or a parabola part as well as one or several parabola parts 15 and one or several further parabola parts 16, 16a, 16b, 16c and 16d, respectively, or some other quadratic curve.
The cross section according to fig. 5 generates, when it runs at right angle through the generatrix lines 17 and 18, respectively, the reflector sections 3 - 6. These sections are limited laterally by the sections 7 - 10 cutting the generated envelope surface along lines 3', 3" - 6', 6". These and other lines must not necessarily be acute lines. Instead, there may be more or less gently rounded transitional areas between interconnecting sections, which latter even may be somewhat convex and/or concave in planes parallel to the generatrix plane. It is important, however, that the design of details as described herein and shown in the drawings is maintained per se and/or in combination for ensuring an advantageous total effect.
The section 7 - 10 are generated, when a parabola part or several composed parabola parts are within a plane, which includes an angle alpha with the cross sectional plane A in figs. 1 - 3 and runs along line or curve 19 respectively 20 respectively 21 respectively 22. The cross sectional plan B includes an angle β with line or curve 19 respectively 20 respectively 21 respectively 22. Conditions are: 0.0 < alfa<= 90.0° ; 0.0 < β <= 90.0°.
The reflector section 7 shown is a mirror image of reflector section 10 in that vertical plane C, which goes through the longitudinal axis of fluorescent tube 13. In the same way, reflector section 8 is a mirror image of reflector section 9 in the same vertical plane. Reflector section 7 is a mirror image of reflector section 8 in that plane, which is formed by the cross section A.
Reflector sections 7 - 10 must not necessarily be mirror images of each other as described above but may be mutually entirely different. All are formed, however, in a manor as described above, but may have mutually different values of angle alpha and angle β. The parabola parts generating the sections may also be different as well as lines or curves 17 - 22.
The reflector sections 11 and 12 are generated by a curve 23' and 24', respectively, which lie in a vertical plane parallel to the longitudinal axis of fluorescent tube 13, and by a line or curve 23 and 24, respectively, standing at right angle to the said vertical plane. The curve 23' and 24', respectively, may consist of one or several straight lines or parabola parts. The reflector sections 11 and 12 are delimited by the sections 7 and 10 respectively 8 and 9, when the former intersect the latter.
The reflector sections 11 and 12 may be mirror images of each other in that vertical plane, which is formed by the cross section A. Deviations as to both generating of and mutual relations between sections 11 and 12 may, however, occur.
As is revealed particularly by figs. 1 and 7, sections 11 and 12 cut at increasing distance from generatrix 23 respectively 24 increasingly deeper into sections 7 and 10 respectively 8 and 9 to end abruptly at a level of between 20% and 70% preferably app. 40% of the reflector height and are bent outwardly, e.g. horizontally in mutually opposite directions to form shelf like steps 25 and 26, respectively, the free outer edge of which lies preferably in the same vertical plane as the free outer edge 7' and 10' respectively 8' and 9' of sections 7 and 10 respectively 8 and 9 as well as the outer lower base part of sections 11 and 12, which may be beveled to form a vertical bevel 27 and 28, respectively. In this way, excellent large abutment surfaces are formed, when the reflectors are to be arranged in series, e.g. according to figs. 8 and 9.
Due to the limited extent in height of the transverse sections, there are formed app. triangle shaped reflector openings 29 and 30, through which a fluorescent tube or several fluorescent tubes may be led. It is also conceivable to arrange the sections 11 and 12 as loose parts or furnish them with vertically throughgoing opening for insertion of fluorescent tubes by radial displacement of same. Where space and other factors allow introduction of fluorescent tubes in axial direction without problems, such insertion and accordingly reflector designs as shown in the drawings are to prefer, as to the reflectors has shown have optimal reflection and strain properties.
The reflector as shown and described has excellent resistance properties, as its structure allows stressing from practically all directions without the sections being deformed or damaged. Therefore, the reflector may be manufactured of very thin material. Furthermore, the structure per se requires a minimum of material, i.e. with respect to achieved illumination effect. Both these circumstances allow together material savings.
The reflector and the light fitting as shown in the drawings gives rise to a rotation symmetrical distribution of light at the same time as there is achieved a very good optical and mechanical shielding and a very high rate of efficiency of app. 75%.
Due to the possibilities of variation as hinted hereinbefore, even an asymmetric light control is possible. Asymmetric light control means that the light distribution of the fitting has its maximum in a direction, which forms an angle with a vertical line from the center of the fitting to a point straight below the light source of the fitting. Asymmetric light control means, if the fitting is located properly at a working place, that the working surface will be well illuminated at the same as possible light reflexes are directed away from the face of a person at the working place, and that considerably batter contrast conditions are achieved compared to when a fitting with symmetric light control is placed straight above a working place.
Reflector designs allowing control of light in arbitrary directions, i.e. in transverse and longitudinal directions and directions there between, render substantially improve possibilities in illumination planning, e.g. with respect to flexibility, illumination effects etc.
It should even be mentioned, that the height of the fitting and the relation between the hide and width of the reflector sections are very critical in this connection apart from the previously mentioned design of the sections. Small changes in any of these respects may entail substantially changed, e.g. deteriorated light distribution and in the latter case considerably lower efficiency. Decisive, exactly calculated changes of e.g. size and design of e.g. the reflector sections may, however, bring about an individually adapted, symmetrical or asymmetrical light control which corresponds to all expectations made as conditions.
It goes without saying, that reflectors according to the invention may be arranged in series not only in a way as shown in figs. 8 and 9 in longitudinal direction of a fitting but even or only in transverse direction of a fitting. Particularly when the outer base area of sections 5 and 6 is straight in transverse direction as shown and/or provided with a bevel similar to bevels 27 and 28 or with an outer building up which renders a vertical and transverse abutment surface, excellent properties are achieved to keep in place without extra means a series of reflectors both in longitudinal and/or transverse direction of a fitting. Naturally, the reflectors may easily be interconnected by e.g. glue and/or mechanical means. The said design of the reflectors concerning the outer shape permits easy and simple insertion into an fitting 31 as shown in fig. 9, where a lower surrounding border 32 may keep in place a series of reflectors even without any extra means. Through one of the end pieces 33, both reflectors and one or several fluorescent tubes may be simply an speedily introduced or removed.
As to proportions of a reflector according to the invention, its extent in plane C corresponds preferably to app. 50% of the extent in plane A, which means length and widths, while the height preferably app. corresponds to the width.
A series of reflectors 1 arranged in a light fitting forms triangle shaped spaces 34 i lateral direction between adjacent reflectors. These spaces may advantageously be used for ventilation of the fitting. Even the interspace formed between the various sections and the lateral surfaces as well as the top surface of a fitting base formed as a parallel epipate may advantageously be used for the same purpose. Furthermore, the outer shape of the reflectors permits in cross section parabola and sector shaped fitting bases apart from the design as shown. The strength of the reflectors allows even use of same as a fitting without any surrounding fitting shell.
A reflector respectively a radiation fitting according to the invention provided with such reflectors may be used for any kind of radiation, e.g. radiation of light, infrared heat and ultraviolet radiation.

Claims

Reflector (1) for an elongated electrrical radiation fitting (31), particularly an elongated fluorescent tube fitting, comprising on the interior side a reflecting layer (2) as well as one or several top sections (3, 4) and longitudinal sections (5, 6) connected thereto and extending in a longitudinal direction of the fitting to said top section(s) (3, 4) and longitudinal sections (5, 6) being connected to oblique or diagonal sections (7-10), said diagonal sections (7-10) being connected to transverse sections (11, 12) arranged transversely relatively to the longitudinal direction of the fitting, which transverse sections connect to a pair of diagonal sections (7 + 10, 8+9) mainly with their ends, characterized in that for the purpose of controlling and shielding a substantial part of the reflected light in diagonal and longitudinal direction of the fitting, at least some of the sections (3-12) including the diagonal sections (7-10) are formed by generatricses (19-24) and in cross section (14-16) by the involutions (14) of a circle or by one or several parabola parts (15) or any other quadratic curve with extension away from a light source (13), and that for the purpose of reflecting a substantial part of the light in longitudinal direction of the fitting, the transverse sections (11, 12) at increasing distance from the associated generatricses (23, 24) cut increasingly deeper in a longitudinal direction into the adjoining diagonal sections (7, 10) respectively (8, 9) to end abruptly at a level of between 20% and 70% of the reflector height.
Reflector according to claim 1, characterized in that the diagonal sections form uniform angles of 30°-60° with the longitudinal axis of the fitting.
Reflector according to claim 1 or 2, characterized in that the reflector comprises two top sections (3, 4), two longitudinal sections (5, 6) connected thereto, four diagonal sections (7-10) connected to both top sections and the longitudinal sections, as well as two transverse sections (11, 12).
Reflector according to any of claims 1 - 3, characterized in that the longitudinal, the diagonal and the transverse sections (5-12) are at least partly formed by a parabola part or several composed parabola parts being situated in a plane, which forms an angle alpha with a cross sectional plane A of the reflector (1), and runs along a line or curve (17-24) being the base line or curve of the respective section, as well as by a vertical plane running through two diagonally relative to each other situated diagonal sections (7 + 9, 8 + 10) forming an angle with the base line or curve of the respective sections with the conditions: 0.0 < (alpha) <= 90.0° ; 0.0 < (β) <= 90.0°.
Reflector according to any of claims 1 - 4, characterized in that the top sections (3, 4) and the longitudinal sections (5, 6) are delimited laterally by the diagonal sections (7-10) cutting the formed enveloped surface along lines (3', 3"-6',6"), the intersection areas being shaped either as acute lines or rounded.
Reflector according to any of claims 1 - 5, characterized in that the transverse sections (11, 12) are bent outwardly preferably horizontally into mutually opposite directions to form shelf-like steps (25, 26), the free outer edges of which lie in a common vertical plane with the free outer edge (7' + 10', 8' + 9') of the adjoining diagonal sections (7 + 10, 8 + 9) and the outer lower base part of the transverse sections (11, 12), which have an outer, vertical bevel (27, 28).
Reflector according to claim 6, characterized in that above the transverse sections (11, 12) there are formed two approximately triangle-shaped reflector openings (29, 30), through which one or several fluorescent tubes (13) are introducible, the transverse sections (11, 12) being either fixed or integrated with the reflector base or being shaped or arranged as loose parts or being provided with vertically throughgoing openings for radial introduction of fluorescent tubes.
Reflector according to any of claims 1 - 7, characterized in that the extension of the reflector (1) in vertical and longitudinal direction are approximately same, while the extension in transverse direction is twice as large as the extension in height or longitudinal direction.
Radiation fitting with a reflector according to any of claims 1 - 8, characterized in that the fitting comprises a plurality of reflectors (1) arranged in series in longitudinal and/or transverse direction of the fitting, at least some of the delimitation lines or surfaces of the reflectors cooperating with the fitting base, e.g. with its border, are triangle-shaped interspaces (34) between adjacent reflectors being provided to participate in ventilating the fitting as ventilation openings.