Patent Description:
Distribution of light produced by a light fixture can be important or even critical in some applications. The light fixture comprises one or more light sources each of which may 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. Furthermore, the light fixture comprises typically means for modifying a light distribution pattern of the one or more light sources, such as for example lampshades and/or optical devices made of transparent material such as e.g. glass or optical silicone. In many office environments, it is desired that light is directed not only towards a floor but towards a ceiling, too. A commonly used solution is to use linear pendant luminaires which have an open top side. A linear pendant luminaire may comprise for example a fluorescent tube or two LED strips facing up and down since LEDs are not omnidirectional.

A known solution to avoid a need for two LED strips is to use a light fixture where light is emitted through side surfaces, too. However, in conjunction with many existing light fixtures where light is emitted through side surfaces, a part of the light is emitted obliquely downwards in directions in which the light may cause undesired glare. Because the emission through the side surfaces may cause glare, there are many limitations concerning positioning of light fixtures of the kind mentioned above in a lighting system for illuminating an office or another room. Therefore, there is a need for light fixtures where a distribution of light is modified so that a part of the light is directed downwards to a floor according to a desired light distribution, another part of the light is directed to a ceiling according to another desired light distribution, and light emitted to unwanted directions and potentially causing glare can be kept at a sufficiently low level. Furthermore, it is advantageous if a technology used in a light fixture allows different designs enabling different outlooks of a light fixture. <CIT> discloses a light fixture.

The following presents a simplified summary in order to provide a basic understanding of some aspects of various invention embodiments.

In this document, the word "geometric" when used as a prefix means a geometric concept that is not necessarily a part of any physical object. The geometric concept can be for example a geometric point, a straight or curved geometric line, a geometric plane, a non-planar geometric surface, a geometric space, or any other geometric entity that is zero, one, two, or three dimensional.

In accordance with the invention, there is provided a new light fixture that can be for example a pendant luminaire.

A light fixture according to the invention comprises:.

The lens section constitutes an optical diverter configured to direct a first part of light emitted by the light source obliquely via a gap between first edges of the first and second side wall sections and a second part of the light emitted by the light source obliquely via a gap between second edges of the first and second side wall sections so that a first angle between a maximum intensity direction of the first part of the light and a direction perpendicular to the first and second side wall sections is smaller than a second angle between a maximum intensity direction of the second part of the light and the direction perpendicular to the first and second side wall sections.

A light fixture according to an exemplifying and non-limiting embodiment is two-sided so that the light fixture further comprises another light source on the first surface of the second side wall section and positioned so that a maximum intensity direction of a light distribution pattern of the other light source is towards the first side wall section, and another lens section placed to cover the other light source and being mirror symmetrical with respect to the lens section on the first side wall section.

A light fixture according to the invention can illuminate both a floor and a ceiling so that light emitted to unwanted directions and potentially causing glare can be kept at a low level. When a light fixture according to an exemplifying and non-limiting embodiment is single-sided, i.e. there is a light source and a lens section on only one of the side wall sections, the light fixture can be used near to a wall so that unwanted bright spots on the wall can be avoided. Likewise, a two-sided light fixture according to an exemplifying and non-limiting embodiment can be used near a wall so that a light source on a side wall section of the light fixture that is farther from the wall is configured to produce less light than the other light source on the other side wall section that is nearer to the wall. For example, the light source on the side wall section farther from the wall can be dimmed or disconnected from an electric supply.

In accordance with the invention, there is provided also a new lighting system that comprises a floor and a ceiling to be illuminated and at least one light fixture according to the invention between the floor and the ceiling, wherein the direction perpendicular to the first and second side wall sections of each light fixture is horizontal, the first edges of the first and second side wall sections are upwards, and the second edges of the first and second side wall sections are downwards.

Various exemplifying and non-limiting embodiments are described in accompanied dependent claims.

Exemplifying and non-limiting embodiments 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 conjunction with the accompanying drawings.

Exemplifying and non-limiting embodiments and their advantages are explained in greater detail below with reference to the accompanying drawings, in which:.

<FIG> shows a top view of a light fixture <NUM> according to an exemplifying and non-limiting embodiment. <FIG> shows a section taken along a line A-A shown in <FIG>. The geometric section plane is parallel with the yz-plane of a coordinate system <NUM>. The light fixture <NUM> comprises first and second side wall sections <NUM> and <NUM> that are a distance D away from each other and have first surfaces <NUM> and <NUM> facing towards each other. In this exemplifying case, the light fixture <NUM> is elongated so that the length L of the light fixture <NUM> is at least two times the above-mentioned distance D. In a light fixture according to an exemplifying and non-limiting embodiment, the distance D between the first and second side wall sections <NUM> and <NUM> is less than or equal to the height H of the first and second side wall sections <NUM> and <NUM>.

The light fixture <NUM> comprises a first light source <NUM> on the first surface <NUM> of the first side wall section <NUM> and positioned so that a maximum intensity direction of a light distribution pattern of the first light source <NUM> is towards the second side wall section <NUM>. The light fixture <NUM> comprises a second light source <NUM> on the first surface <NUM> of the second side wall section <NUM> and positioned so that a maximum intensity direction of a light distribution pattern of the second light source <NUM> is towards the first side wall section <NUM>. The light distribution pattern of the first light source <NUM> means a light distribution pattern that would exist if the light emitted by the first light source <NUM> were not modified. Correspondingly, the light distribution pattern of the second light source <NUM> means a light distribution pattern that would exist if the light emitted by the second light source <NUM> were not modified. The first and second light sources <NUM> and <NUM> can be for example LED strips or some other suitable elongated light sources.

The light fixture <NUM> comprises first and second lens sections <NUM> and <NUM> that are made of transparent material having a refractive index greater than one. The transparent material can be for example acrylic plastic, polycarbonate, optical silicone, or glass. A method of manufacture of the first and second lens sections <NUM> and <NUM> can be for example mold casting or extruding. The first lens section <NUM> is placed to cover the first light source <NUM>, and the second lens section <NUM> is placed to cover the second light source <NUM>. The first lens section <NUM> constitutes an optical diverter configured to direct a first part of light emitted by the first light source <NUM> obliquely via a gap <NUM> between first edges of the first and second side wall sections <NUM> and <NUM> and to direct a second part of the light emitted by the first light source <NUM> obliquely via a gap <NUM> between second edges of the first and second side wall sections <NUM> and <NUM>. Correspondingly, the second lens section <NUM> constitutes an optical diverter configured to direct a first part of light emitted by the second light source <NUM> obliquely via the gap <NUM> and to direct a second part of the light emitted by the second light source <NUM> obliquely via the gap <NUM>. In <FIG>, exemplifying light beams belonging to the first parts of the light emitted by the first and second light sources <NUM> and <NUM> are depicted with dashed line arrows and exemplifying light beams belonging to the second parts of the light emitted by the first and second light sources <NUM> and <NUM> are depicted with dash-and-dot line arrows. As illustrated in <FIG>, the light beams emitted by the first light source <NUM> are arranged to cross the light beams emitted by the second light source <NUM>.

In a light fixture according to an exemplifying and non-limiting embodiment, the first lens section <NUM> comprises a first section <NUM>, a second section <NUM>, and a V-shaped recess <NUM> between the first and second sections <NUM> and <NUM> and configured to divide the light emitted by the first light source <NUM> to the first part exiting via the gap <NUM> and to the second part exiting via the gap <NUM>. In this exemplifying case, an outermost surface <NUM> of the first section <NUM> is configured to act as a total internal reflection "TIR" surface to shape the distribution pattern of the first part of the light emitted by the first light source <NUM>, and a surface <NUM> defining one side of the V-shaped recess <NUM> and belonging to the second section <NUM> is configured to act as a total internal reflection "TIR" surface to shape the distribution pattern of the second part of the light emitted by the first light source <NUM>. It is also possible that the surface <NUM> is configured to act as a light refracting surface to shape the distribution pattern of the second part of the light emitted by the first light source <NUM>. Correspondingly, the second lens section <NUM> comprises a first section <NUM>, a second section <NUM>, and a V-shaped recess <NUM> between the first and second sections and configured to divide the light emitted by the second light source <NUM> to the first and second parts of the light emitted by the second light source <NUM>. In this exemplifying case, an outermost surface <NUM> of the first section <NUM> is configured to act as a total internal reflection "TIR" surface to shape the distribution pattern of the first part of the light emitted by the second light source <NUM>, and a surface <NUM> defining one side of the V-shaped recess <NUM> and belonging to the second section <NUM> is configured to act as a total internal reflection "TIR" surface to shape the distribution pattern of the second part of the light emitted by the second light source <NUM>. It is also possible that the surface <NUM> is configured to act as a light refracting surface to shape the distribution pattern of the second part of the light emitted by the second light source <NUM>.

In a light fixture according to an exemplifying and non-limiting embodiment, the first lens section <NUM> is configured to direct from <NUM> % to <NUM> % of the light emitted by the first light source <NUM> to be the first part of the light emitted by the first light source <NUM> and correspondingly the second lens section <NUM> is configured to direct from <NUM> % to <NUM> % of the light emitted by the second light source <NUM> to be the first part of the light emitted by the second light source <NUM>.

In a light fixture according to an exemplifying and non-limiting embodiment, the first lens section <NUM> is configured to direct at most <NUM> % of the light emitted by the first light source <NUM> to be the first part of the light emitted by the first light source <NUM> and correspondingly the second lens section <NUM> is configured to direct at most <NUM> % of the light emitted by the second light source <NUM> to be the first part of the light emitted by the second light source <NUM>.

<FIG> illustrates a light distribution produced by the light fixture <NUM>. A light distribution pattern <NUM> represents the first parts of the light emitted by the first and second light sources <NUM> and <NUM>, and a light distribution pattern <NUM> represents the second parts of the light emitted by the first and second light sources <NUM> and <NUM>. The first lens section <NUM> is shaped so that a first angle θ<NUM> between a maximum intensity direction of the first part of the light emitted by the first light source <NUM> and a direction perpendicular to the first and second side wall sections <NUM> and <NUM> is smaller than a second angle θ<NUM> between a maximum intensity direction of the second part of the light emitted by the first light source <NUM> and the direction perpendicular to the first and second side wall sections. In <FIG>, the direction perpendicular to the first and second side wall sections is parallel with the y-axis of the coordinate system <NUM>. The first angle θ<NUM> can be for example from <NUM> degrees to <NUM> degrees, and the second angle θ<NUM> can be for example from <NUM> degrees to <NUM> degrees.

In the exemplifying light fixture <NUM> shown in <FIG>, the second lens section <NUM> is mirror symmetrical with respect to the first lens section <NUM> and therefore, as shown in <FIG>, the light distribution produced by the light fixture <NUM> is symmetrical with respect to a geometric plane parallel with the xz-plane of the coordinate system <NUM>. It is however also possible to that the lens sections on opposite sides of the light fixture are different from each other in order achieve an asymmetrical light distribution.

<FIG> shows a section view of a light fixture <NUM> according to an exemplifying and non-limiting embodiment. The geometric section plane is parallel with the yz-plane of a coordinate system <NUM>. The light fixture <NUM> comprises first and second side wall sections <NUM> and <NUM> that are a distance D away from each other and have first surfaces <NUM> and <NUM> facing towards each other. The light fixture <NUM> comprises a light source <NUM> on the first surface <NUM> of the first side wall section <NUM> and positioned so that a maximum intensity direction of a light distribution pattern of the first light source <NUM> is towards the second side wall section <NUM>. The light distribution pattern of the light source <NUM> means a light distribution pattern that would exist if the light emitted by the light source <NUM> were not modified. The light source <NUM> can be for example a LED strip or another suitable light source.

The light fixture <NUM> comprises a lens section <NUM> that is made of transparent material having a refractive index greater than one. The lens section <NUM> is placed to cover the light source <NUM>. The lens section <NUM> constitutes an optical diverter configured to direct a first part of light emitted by light source <NUM> obliquely via a gap <NUM> between first edges of the first and second side wall sections <NUM> and <NUM> and to direct a second part of the light emitted by the light source <NUM> obliquely via a gap <NUM> between second edges of the first and second side wall sections <NUM> and <NUM>. In <FIG>, exemplifying light beams belonging to the first part of the light emitted by the light source <NUM> are depicted with dashed line arrows and exemplifying light beams belonging to the second part of the light emitted by the light source <NUM> are depicted with dash-and-dot line arrows.

In a light fixture according to an exemplifying and non-limiting embodiment, the lens section <NUM> comprises a first section <NUM>, a second section <NUM>, and a V-shaped recess <NUM> between the first and second sections and configured to divide the light emitted by the light source <NUM> to the first part exiting via the gap <NUM> and to the second part exiting via the gap <NUM>. In this exemplifying case, an outermost surface <NUM> of the first section <NUM> is configured to act as a total internal reflection "TIR" surface to shape the distribution pattern of the first part of the light emitted by the light source <NUM>, and a surface <NUM> defining one side of the V-shaped recess <NUM> and belonging to the second section <NUM> is configured to act as a light refracting surface to shape the distribution pattern of the second part of the light emitted by the light source <NUM>. It is also possible that the surface <NUM> is configured to act as a total internal reflection "TIR" surface to shape the distribution pattern of the first part of the light emitted by the light source <NUM>.

In a light fixture according to an exemplifying and non-limiting embodiment, the lens section <NUM> is configured to direct from <NUM> % to <NUM> % of the light emitted by the light source <NUM> to be the first part of the light emitted by the light source <NUM>. In a light fixture according to an exemplifying and non-limiting embodiment, the lens section <NUM> is configured to direct at most <NUM> % of the light emitted by the light source <NUM> to be the first part of the light emitted by the light source <NUM>. In a light fixture according to an exemplifying and non-limiting embodiment, the lens section <NUM> is configured to direct at most <NUM> % of the light emitted by the light source <NUM> to be the first part of the light emitted by the light source <NUM>. In a light fixture according to an exemplifying and non-limiting embodiment, the lens section <NUM> is configured to direct at most <NUM> % of the light emitted by the light source <NUM> to be the first part of the light emitted by the light source <NUM>.

<FIG> illustrates a light distribution produced by the light fixture <NUM>. A light distribution pattern <NUM> represents the first part of the light emitted by the light sources <NUM>, and a light distribution pattern <NUM> represents the second part of the light emitted by the light source <NUM>. The lens section <NUM> is shaped so that a first angle θ<NUM> between a maximum intensity direction of the first part of the light emitted by the light source <NUM> and a direction perpendicular to the first and second side wall sections <NUM> and <NUM> is smaller than a second angle θ<NUM> between a maximum intensity direction of the second part of the light emitted by the light source <NUM> and the direction perpendicular to the first and second side wall sections. In <FIG> and <FIG>, the direction perpendicular to the first and second side wall sections is parallel with the y-axis of the coordinate system <NUM>. The first angle θ<NUM> can be for example from <NUM> degrees to <NUM> degrees, and the second angle θ<NUM> can be for example from <NUM> degrees to <NUM> degrees.

<FIG> show top views of light fixtures 300a and 300b according to exemplifying and non-limiting embodiments. Sections taken along lines A1-A1 and A2-A2 can be for example like the section shown in <FIG>. In this exemplifying case, the side walls of the light fixtures have curved shapes so that the distance D is dependent on a position in the longitudinal directions of the light fixtures 300a and 300b. The longitudinal directions are parallel with the y-axis of a coordinate system <NUM>. The lens sections 305a and 306a can be formed by a single lens element.

Correspondingly, the lens sections 305b and 306b can be formed by a single lens element. The lens element can be made of flexible material, such as e.g. optical silicone, which allows the lens element to be adapted to the shape of the light fixture.

<FIG> illustrates a lighting system according to an exemplifying and non-limiting embodiment. The lighting system comprises a floor <NUM>, a ceiling <NUM>, a wall structure <NUM>, first light fixtures 400a and 400b, and a second light fixture 400c. In this exemplifying case, the light fixtures 400a-400c are pendant luminaires between the floor <NUM> and the ceiling <NUM>. The light fixtures 400a and 400b can be for example like the light fixture <NUM> shown in <FIG>. The light fixture 400c produces more light in directions obliquely away from the wall structure <NUM> than in directions obliquely towards the wall structure. The light fixture 400c can be for example like the light fixture <NUM> shown in <FIG>. The light fixtures 400a-400c are installed so that the first part of light emitted by each light fixture illuminates the ceiling <NUM> and the second part of light emitted by each light fixture illuminates the floor <NUM>. The distributions of light emitted by the light fixtures 40a-400c are depicted with dashed lines. With the terms used in explaining <FIG>, and <FIG>, the installation of the light fixtures 400a-400c can be described more exactly as follows:.

<FIG> illustrates a lighting system according to an exemplifying and non-limiting embodiment. The lighting system shown in <FIG> is otherwise like the lighting system shown in <FIG>, but the light fixture 400d is like the light fixture <NUM> shown in <FIG>. The light fixture 400d produces more light in directions obliquely away from the wall structure <NUM> than in directions obliquely towards the wall structure. The asymmetric light distribution pattern of the light fixture 400d is implemented so that the light source of the light fixture 400d that is nearer to the wall structure <NUM> is configured to produce more light than the other light source of the light fixture 400d. For example, the other light source can be dimmed or disconnected from an electric supply. In the lighting system illustrated in <FIG>, all the light fixtures are like each other and thus a product portfolio of a light fixture vendor can simpler.

As shown in <FIG>, the light fixtures do not substantially emit light in directions S1 and S2 in which the light would cause harmful glare. Furthermore, as the light distribution patterns of the light fixtures 400c and 400d are asymmetric as shown in <FIG>, unwanted bright spots on the wall structure <NUM> can be avoided.

<FIG> shows a section view of a light fixture <NUM> according to an exemplifying and non-limiting embodiment. The geometric section plane is parallel with the yz-plane of a coordinate system <NUM>. The light fixture <NUM> comprises first and second side wall sections <NUM> and <NUM> that are a distance away from each other and have first surfaces <NUM> and <NUM> facing towards each other. The light fixture <NUM> comprises a first light source <NUM> on the first surface <NUM> of the first side wall section <NUM> and a second light source <NUM> on the first surface <NUM> of the second side wall section <NUM>. The light fixture <NUM> comprises first and second lens sections <NUM> and <NUM> that are made of transparent material having a refractive index greater than one. The first lens section <NUM> is placed to cover the first light source <NUM>, and the second lens section <NUM> is placed to cover the second light source <NUM>. In this exemplifying case, the first and second lens sections <NUM> and <NUM> are connected to each other by a connection section <NUM>. The first and second lens sections <NUM> and <NUM> and the connection section <NUM> may constitute a single piece of the above-mentioned transparent material.

Claim 1:
A light fixture (<NUM>, <NUM>, 300a, 300b, 400a, 400b, 400c, <NUM>) comprising:
- first and second side wall sections (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) being a distance (D) away from each other and having first surfaces (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) facing towards each other, and
- a first light source (<NUM>, <NUM>, <NUM>) on the first surface of the first side wall section and positioned so that a maximum intensity direction of a light distribution pattern of the first light source is towards the second side wall section,
characterized in that the light fixture comprises a first lens section (<NUM>, <NUM>, <NUM>) made of transparent material having a refractive index greater than one and placed to cover the first light source, wherein the first lens section constitutes an optical diverter configured to direct a first part of light emitted by the first light source obliquely via a gap (<NUM>, <NUM>) between first edges of the first and second side wall sections and a second part of the light emitted by the first light source obliquely via a gap (<NUM>, <NUM>) between second edges of the first and second side wall sections, a first angle (θ<NUM>) between a maximum intensity direction of the first part of the light emitted by the first light source and a direction perpendicular to the first and second side wall sections being smaller than a second angle (θ<NUM>) between a maximum intensity direction of the second part of the light emitted by the first light source and the direction perpendicular to the first and second side wall sections.