WO2014188066A1

WO2014188066A1 - A light guide system

Info

Publication number: WO2014188066A1
Application number: PCT/FI2014/050379
Authority: WO
Inventors: Hannu Hukkanen; Tero MÄKINEN
Original assignee: Ledil Oy
Priority date: 2013-05-21
Filing date: 2014-05-20
Publication date: 2014-11-27
Also published as: EP2999918A1

Abstract

A light guide system comprises a first element (201) that comprises a first reflective surface (203) for reflecting at least a part of a first portion of light emitted by a light source (202) and an opening (204) for constituting a passage for a second portion of the light. The light guide system further comprises one or more second elements (205a-205c) each comprising a second reflective surface (206a-206c) and being shaped to fit with the opening of the first element so that the second element is attachable to the first element for arranging the second reflective surface to reflect at least a part of the second portion of the light to a spatial area where the first portion of the light is directed to. Different light distribution patterns can be obtained by using different second elements together with the first element.

Description

A light guide system

Field of the invention

The invention relates generally to illuminating engineering. More particularly, the invention relates to a light guide system for modifying a light distribution pattern of a light source that can be, for example but not necessarily, a light emitting diode "LED".

Background

Distribution of light produced by a light source can be important or even critical in some applications. The light source can comprise, for example but not necessarily, one or more light emitting diodes "LED", one or more filament lamps, or one or more gas-discharge lamps. Figure 1 shows an exemplifying light guide 101 according to the prior art for modifying a light distribution pattern of a light source 102. Electrical wires connected to the light source 102 are not shown in figure 1 . The light guide comprises a reflective surface 103 for reflecting at least a part of a first portion of the light emitted by the light source 102 and an opening 104 for constituting a passage for a second portion of the light. In figure 1 , some of the light beams belonging to the first portion of the light are depicted with dashed line arrows and some of the light beams belonging to the second portion of the light are depicted with dash-and-dot line arrows. Light guides of the kind described above can be used, for example, for decoration purposes so that the first and second portions of the light are illuminating a wall or a ceiling. In this document the term "light guide" is not limited to mean only devices designed to transport light from a light source to a point at some distance by means of total internal reflection but the term "light guide" covers different devices for modifying a light distribution pattern of a light source by means of e.g. the total internal reflection, surface reflection, refraction, etc. and their various combinations. For example, in the context of this document, the term "light guide" is to be understood so broadly that e.g. a mirror is covered by the term "light guide" because a mirror is capable of guiding light and modifying a light distribution pattern. In some cases a designer of an illumination system may want to provide different distribution patterns of the first and second portions of the light than in some other cases. Needs and desires of the kind described above are typically responded to by providing a set of mutually different light guide variations with the aid of which different light distribution patterns can be produced. An inherent inconvenience related to this approach is that the different light guide variations increase the product portfolio of a light guide vendor and thus complicate the product management.

Summary The following presents a simplified summary in order to provide a basic understanding of some aspects of various embodiments of the invention. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments of the invention.

In accordance with the invention, there is provided a new light guide system for modifying the light distribution pattern of a light source. A light guide system according to the invention comprises: - a first element comprising a fastening section for fastening the first element to an external mechanical structure and a first reflective surface for reflecting at least a part of a first portion of light emitted by the light source and an opening for constituting a passage for a second portion of the light, and

- one or more second elements each comprising a second reflective surface and being shaped to fit with the opening of the first element so that the second element is attachable to the first element so as to arrange the second reflective surface to reflect at least a part of the second portion of the light to a spatial area where the first portion of the light is directed to. Different light distribution patterns can be obtained by using different second elements together with the first element, and thus there is no need to change the whole light guide system for changing the light distribution pattern. Because the first element comprises the fastening section for fastening the first element to an external mechanical structure, the first element can be used also without any second element.

In accordance with the invention, there is provided also a new illuminator device comprising at least one light source and at least one light guide system according to the invention. The at least one light source may comprise, for example, one or more light emitting diodes "LED".

In accordance with the invention, there is provided also a method of manufacture of a light guide system according to the invention. The method comprising:

- mold casting a single piece that comprises a first section having the form of the above-mentioned first element, one or more second sections each hav- ing the form of one of the above-mentioned second elements, and breakable lamps connecting the first section and the one or more second sections to constitute the single piece, and

- coating the single piece with a layer of metal.

In accordance with the invention, there is provided also a new mold having a form suitable for manufacturing, by mold casting, one or more pieces having the forms of the first element and the one or more second elements of a light guide system according to the invention.

A number of exemplifying and non-limiting embodiments of the invention are described in accompanied dependent claims. Various exemplifying and non-limiting embodiments of the invention both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying embodiments when read in connection with the accompanying drawings. The verbs "to comprise" and "to include" are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of "a" or "an", i.e. a singular form, throughout this document does not exclude a plurality.

Brief description of the figures

The exemplifying and non-limiting embodiments of the invention and their advantages are explained in greater detail below with reference to the accompanying drawings, in which: figure 1 shows a light guide according to the prior art, figures 2a, 2b and 2c illustrate a light guide system according to an exemplifying embodiment of the invention, figure 3 shows a light guide system according to an exemplifying embodiment of the invention, figure 4 shows a light guide system according to an exemplifying embodiment of the invention, figure 5 shows an illuminator device according to an exemplifying embodiment of the invention, and figure 6 shows a flowchart of a method according to an exemplifying embodiment of the invention for manufacturing a light guide system according to an exemplifying embodiment of the invention.

Figure 1 has already been explained in the Background-section of this document. Description of exemplifying embodiments

Figures 2a illustrates a light guide system according to an exemplifying embodi- ment of the invention for modifying the light distribution pattern of a light source 202 that may comprise, for example but not necessarily, one or more light emitting diodes "LED" which may have different colors and located in a symmetrical or asymmetrical pattern, one or more filament lamps which may have different colors and located in a symmetrical or asymmetrical pattern, or one or more gas- discharge lamps which may have different colors and located in a symmetrical or asymmetrical pattern. Electrical wires connected to the light source 202 are not shown in figure 2a. The light guide system comprises a first element 201 and second elements 205a, 205b, and 205c. The first element 201 comprises a first reflective surface 203 for reflecting at least a part of a first portion of the light emitted by the light source 202, and an opening 204 for constituting a passage for a second portion of the light. The first element 201 further comprises a fastening section 210 for fastening the first element to an external mechanical structure e.g. a wall. The fastening section can be a same piece of material as the other portion of the first element or the fastening section can be a separate piece attached to the other portion of the first element. In figure 2a, some of the light beams belonging to the first portion of the light are depicted with dashed line arrows and some of the light beams belonging to the second portion of the light are depicted with dash-and-dot line arrows. Each of the second elements 205a-205c comprises a second reflective surface. The second reflective surfaces are denoted in figure 2a with references 206a, 206b, and 206c. Each of the second elements 205a-205c is shaped to fit with the opening 204 of the first element so that the second element is at- tachable to the first element and thereafter non-destructively detachable from the first element. When one of the second elements 205a-205c has been placed on the opening 204 of the first element 201 , the reflective surface of the second element under consideration is capable of reflecting at least a first part of the second portion of the light to a spatial area where the first portion of the light is directed to. Figures 2b and 2c illustrate a situation where the second element 205a has been placed on the opening of the first element 201 . Figure 2c shows a section taken along the line A-A shown in figure 2b. As can be understood from figure 2b, the second reflective surface 206a of the second element 205a reflects a part of the light that would pass the opening of the first element if the second element 205a were removed. Because the first element 201 comprises the fastening section 210 and the second elements 205a-205c are not needed to provide any mechanical support to the first element, the first element can be used also without any of the second elements 205a-205c. In the exemplifying light guide system illustrated in figures 2a-2c, the second element 205a comprises an opening 207a for constituting, when the second element 205a has been attached to the first element 201 , a passage for a second part of the second portion of the light. As mentioned earlier, the second portion of the light is the light that passes the opening 204 of the first element 201 when no second element is used. Correspondingly, the second element 205b comprises an opening 207b that is smaller than the opening 207a of the second element 205a. The second element 205c does not comprise any opening and thus the second element 205c is configured to reflect substantially the entire second portion of the light when the second element 205c has been attached to the first element. Thus, the amount of the light directed substantially to the positive y-direction of the coordinate system 299 can be altered by changing the second element. In the exemplifying case illustrated in figures 2a-2c, the first element 201 comprises a third reflective surface 208 for modifying the distribution of light that has passed the open- ing 204 of the first element in a case where there is no second element or in a case where there is a second element provided with an opening. The amount of the light directed substantially to the negative y-direction of the coordinate system 299 is dependent only in a small extent on the second element being used.

The first element 201 and the second elements 205a-205c of the light guide sys- tern illustrated in figures 2a-2c can be, for example, metal or metal coated plastic. The metal can be, for example, aluminum or silver.

Figure 3 shows a light guide system according to an exemplifying embodiment of the invention. The light guide system comprises a first element 301 and second elements 305a and 305b. The first element 301 comprises a first reflective surface 303 and an opening 304. The first element 301 further comprises a fastening section 310 for fastening the first element to an external mechanical structure. Each of the second elements 305a and 305b comprises a second reflective surface. Each of the second elements 305a and 305b is shaped to fit with the opening 304 of the first element so that the second element is attachable to the first element and thereafter non-destructively detachable from the first element. In the exemplifying case illustrated in figure 3, the second element 305a comprises an opening 307 that is a through hole and the second element 305b is configured to fully close the opening 304 of the first element 301 .

In the exemplifying case illustrated in figure 3, the first reflective surface 303 is shaped to constitute substantially a part of an inner surface of an elliptic parabo- id. In a coordinate system 399, the elliptic paraboloid can be defined with the equation: y = y₀ - (x - x₀)²/a² - (z - z₀)²/b², where x₀, yo and z₀ are the coordinates of the top of the elliptic paraboloid and a and b are constants. The opening 304 of the first element is located at the top of the elliptic paraboloid. In a special case where the elliptic paraboloid is a paraboloid of revolution, i.e. a = b, the first reflec- tive surface 303 can be considered to be defined substantially by a concave side of an arc 322 of a parabola that is rotated around a symmetry axis 323 that is parallel with the y-axis of the coordinate system 399.

In the exemplifying case illustrated in figure 3, the first element 301 comprises a third reflective surface that comprises two side walls 308a and 308b and a middle wall 308c between the side walls. The middle wall 308c is shaped to constitute substantially a part of a surface of revolution defined by a concave side of an arc 324 of a parabola rotated around a tangent line 325 that touches the top of the parabola and is perpendicular to the symmetry axis 323 of the above-mentioned elliptic paraboloid. In the coordinate system 399, the surface of revolution can be defined with the equation: z = z₀ - V{ V[(x - x₀)²/c² + (y - yo)²/c²] }, where x₀, yo and zo are the coordinates of the apex of the surface of revolution and c is a constant.

Figure 4 shows a light guide system according to an exemplifying embodiment of the invention. The light guide system comprises a first element 401 and second elements 405a, 405b, and 405b. The first element 401 comprises a first reflective surface 403 and an opening 404. The first element 401 further comprises a fastening section 410 for fastening the first element to an external mechanical structure. Each of the second elements 405a-405c comprises a second reflective surface. Each of the second elements 405a-405c is shaped to fit with the opening 404 of the first element so that the second element is attachable to the first element and thereafter non-destructively detachable from the first element. In the exemplifying case illustrated in figure 4, the light guide system further comprises breaka- ble lamps 409a, 409b, and 409c connecting the first element 401 and the second elements 405a-405c to constitute a single piece that is straightforward to manufacture and handle in a product management system.

Figure 5 shows an illuminator device according to an exemplifying embodiment of the invention. The illuminator device comprises light sources 502a and 502b, and light guide systems 515a and 515b. Each of the light guides is according to an embodiment of the invention. Each of the light sources 502a and 502b may comprise at least one light emitting diode "LED". The illuminator device shown in figure 5 can be installed on a flat surface, e.g. a wall or a ceiling, so that surfaces 516a, 516b, 516c, and 516d of fastening sections 510a and 510b are placed against the flat surface.

Figure 6 shows a flowchart of a method according to an exemplifying embodiment of the invention for manufacturing a light guide system according to an exemplifying embodiment of the invention. The method comprises the following actions: - action 601 : mold casting a single piece that comprises a first section having the form of the first element of the light guide system, one or more second sections each having the form of one of the second elements of the light guide system, and breakable lamps connecting the first section and the one or more second sections to constitute the single piece, and - action 602: coating the single piece with a layer of metal.

The specific examples provided in the description given above should not be construed as limiting the scope and/or the applicability of the appended claims.

Claims

What is claimed is:

1 . A light guide system for modifying a light distribution pattern of a light source, the light guide system comprising:

- a first element (201 , 301 , 401 ) comprising a first reflective surface (203, 303, 403) for reflecting at least a part of a first portion of light emitted by the light source and an opening (204, 304, 404) for constituting a passage for a second portion of the light, wherein the first element further comprises a fastening section (210, 310, 410, 510a, 510b) for fastening the first element to an external mechanical structure, characterized in that the light guide system further comprises one or more second elements (205a-205c, 305a, 305b, 405a-405c) each comprising a second reflective surface (206a-206c) and being shaped to fit with the opening of the first element so that the second element is attachable to the first element so as to arrange the second reflective surface to reflect at least a first part of the second portion of the light to a spatial area where the first portion of the light is directed to.

2. A light guide system according to claim 1 , wherein the second element (205a-205c, 305a, 305b, 405a-405c), when having been attached to the first element to reflect at least the first part of the second portion of the light, is nondestructive^ detachable from the first element.

3. A light guide system according to claim 1 or 2, wherein the second element (205a, 205b, 405a, 405b) comprises an opening (207a, 207b) for constituting, when the second element has been attached to the first element, a passage for a second part of the second portion of the light.

4. A light guide system according to claim 1 or 2, wherein the second element (205c, 305b) is configured to reflect substantially the entire second portion of the light when the second element has been attached to the first element.

5. A light guide system according to claim 1 , wherein: - a first one (205c) of the second elements is configured to reflect substantially the entire second portion of the light when the first one of the second elements has been attached to the first element,

- a second one (205b) of the second elements comprises an opening (207b) for constituting, when the second one of the second elements has been attached to the first element, a passage for a second part of the second portion of the light, and

- a third one (205a) of the second elements comprises an opening (207a) greater than the opening of the second one of the second elements.

6. A light guide system according to any of claims 1 -5, wherein the first reflective surface (303) is shaped to constitute substantially a part of an inner surface of an elliptic paraboloid and the opening of the first element being at a location of a top of the elliptic paraboloid.

7. A light guide system according to any of claims 1 -6, wherein the first element comprises a third reflective surface (208, 308a-308c) for modifying a distribution of light passed the opening of the first element.

8. A light guide system according to claim 7, wherein the third reflective surface comprises two side walls (308a, 308b) and a middle wall (308c) between the side walls, the middle wall being shaped to constitute substantially a part of a surface of revolution defined by a concave side of an arc (324) of an parabola rotated around a tangent line (325) of the parabola, the tangent line touching a top of the parabola.

9. A light guide system according to any of claims 1 -8, wherein the first element and the one or more second elements comprise metal coated plastic.

10. A light guide system according to any of claims 1 -9, wherein the light guide system further comprises breakable lamps (409a-409c) connecting the first element (401 ) and the one or more second elements (405a-405c) to constitute a single piece.

1 1 . An illuminator device comprising at least one light guide system (515a, 515b) according to any of claims 1 -9, and at least one light source (502a, 502b).

12. A method of manufacture of a light guide system according to any of claims 1 -10, the method comprising:

- mold casting (601 ) a single piece that comprises a first section having a form of the first element, one or more second sections each having a form of one of the second elements, and breakable lamps connecting the first section and the one or more second sections to constitute the single piece, and

- coating (602) the single piece with a layer of metal.

13. A mold having a form suitable for manufacturing, by mold casting, one or more pieces having forms of the first element and the one or more second elements of a light guide system according to any of claims 1 -10.