AT16724U1 - Light guide element and luminaire with a light guide element - Google Patents

Abstract

The invention relates to a light guide element with a plate-shaped partial area (1), through which a first surface area (2) delimiting a first half space (H1) and, opposite thereto, a second surface area (3) delimiting a second half space (H2) are formed, whereby the first surface area (2) extends at least substantially within a first plane (E1) and the second surface area (3) at least substantially within a second plane (E2) parallel to the first plane (E1), and a peripheral edge area (4 ), through which the first surface area (2) is connected to the second surface area (3), the light guide being provided such that a light is radiated into the light guide via the peripheral edge area (4) and further at least partially via the first surface area (2) is delivered into the first half-space (H1), with an edge region (5) lying opposite the edge edge region (4), such is designed so that the light-representing light rays (L1, L2, L3, L4) that fall into the edge region (5) are at least predominantly deflected in such a way that they leave the light guide element directed into the second half-space (H2).

Description

description

LIGHT GUIDE ELEMENT AND LUMINAIRE WITH A LIGHT GUIDE ELEMENT

The invention relates to a light guide element, and a lamp with such a light guide element.

In lighting technology, it is known to use flat light guides, on the end faces of which light is coupled. Such light guides are used for example in floor lamps or ceiling lamps, whereby they are aligned horizontally in the operating state of the lamp. Here, light sources in the form of LEDs (LED: light-emitting diode) are arranged on at least one long side of the light guide, so that their light shines into the light guide; the light is thus coupled into the light guide at the front. The light is then forwarded and distributed by means of total reflections and finally emitted into the lower half-space via the flat side of the light guide pointing downwards.

In this concept, it is known to arrange light sources on two opposite sides of the light guide. However, this is associated with a correspondingly increased outlay. In addition, the design options of the luminaire are inevitably limited due to the arrangement of the light sources on both sides.

However, it is also possible to make a light coupling only on one long side. In this case, however, it has been shown that the side of the light guide opposite the light sources generally has to be covered with a frame element or the like in order to avoid an uncontrolled light emission here. Such light emission can generally lead to undesirable glare. In this case, too, a corresponding frame or cover element limits the design options with regard to the external appearance of the luminaire in question.

The invention has for its object to provide a corresponding improved light guide element and a corresponding improved lamp.

In particular, the design options of the lamp should be improved by the light guide element.

This object is achieved according to the invention with the objects mentioned in the independent claims. Particular embodiments of the invention are specified in the dependent claims.

According to the invention, a light guide element is provided which has a plate-shaped partial area through which a first surface area delimiting a first half space and opposite thereto a second surface area delimiting a second half space are formed, the first surface area being at least substantially within extends a first plane and the second surface area at least substantially within a second plane parallel to the first plane. Furthermore, the light guide element has an edge edge area through which the first surface area is connected to the second surface area, the light guide being provided for light to be radiated into the light guide via the edge edge area and further at least partially over the first surface area into the first Half space is delivered. Furthermore, the light guide element has an edge area opposite the edge edge area, which is designed in such a way that light rays representing the light that fall into the edge area are deflected, at least predominantly, in such a way that they leave the light guide element directed into the second half space.

A suitable frameless use of the light guide element is made possible in particular by the edge region designed in this way.

[0010] The edge region preferably has a surface section which extends between the first plane and the second plane and is shaped in this way, in particular

is designed curved so that the light rays are totally reflected on the surface section. In this way it can be prevented that the light beams leave the light guide element at this point and subsequently lead to undesired glare.

[0011] The light guide element is preferably designed in profile form, the edge region extending parallel to the profile axis. In this way, large-area light emission can be achieved in particular over the first surface area.

[0012] The edge region preferably has a projecting region which extends beyond the second plane. In this way it can in particular be suitably achieved that the light rays incident in the edge region are subsequently emitted into the second half space. The probability that the light rays strike the surface section of the edge area in such a way that they are refracted there and thus emerge from the light guide element at this point can be significantly reduced if the protruding area extends a measure further in the direction of the edge edge area than that Surface section, in particular if the following applies to the dimension: x> d tan x, where x denotes the dimension, d a thickness of the plate-shaped partial region and a a critical angle, which depends on the refractive index of a material of the light guide and the refractive index of Air gives.

Preferably, the projecting area has an obliquely directed flank area in the second half space, which includes an angle with the second surface area that is not greater than the sum of 90 ° and the critical angle. A particularly large proportion of the light rays entering the edge region can thus be deflected by the edge region in such a way that they are subsequently emitted into the second half space.

Preferably, the plate-shaped portion and the edge area are formed from only one material. In this way, it is particularly expedient to achieve that the two ranges mentioned have the same refractive index.

[0015] Furthermore, the plate-shaped partial area and the edge area are preferably designed to form a coherent piece or in one piece. This is particularly advantageous with regard to the transition of the light rays from the plate-shaped partial area to the edge area.

According to a second aspect of the invention, a lamp is provided with a light guide element according to the invention, and with a light source, in particular an LED light source, which is designed and arranged such that a light emitted by the light source as intended over the edge area of the light guide element in this entry.

Preferably, the lamp is designed such that the light guide element is oriented in a state intended for operation of the lamp such that the first plane is at least substantially horizontal and the first surface area points downward. In this way, light can be emitted in a particularly suitable manner via the first surface area into the lower half space and via the edge area into the upper half space.

Preferably, the edge region of the light guide element forms an outer boundary of the lamp. A corresponding frame or cover element can thus be dispensed with, in particular in comparison with the prior art mentioned at the outset. The external appearance of the lamp can thus be designed more freely.

The lamp is preferably designed as a floor lamp or as a pendant lamp. The use of a light guide element according to the invention is particularly suitable here.

[0020] The luminaire is preferably designed in such a way that the light output is provided via the first surface area for generating direct lighting and the light output via the edge area is used for generating indirect lighting.

The invention is described below using an exemplary embodiment and with reference to

the drawings explained in more detail. Show it:

1 shows a perspective sketch of a light guide element according to the invention, [0023] FIG. 2 shows a corresponding cross-sectional sketch,

3 shows a cross-sectional sketch of the edge region of the light guide element,

Fig. 4 is a sketch of a lamp according to the invention and

5 shows a cross-sectional sketch of an edge area according to a variant.

1 shows a perspective sketch of a light guide element according to the invention, FIG. 2 shows a corresponding cross section. In the example shown, the light guide element is designed in profile form, the cross section shown in FIG. 2 corresponding to a section normal to the profile axis.

The light guide element has a plate-shaped partial area 1, through which a first surface area 2 delimiting a first half space H7 and, opposite thereto, a second surface area 3 delimiting a second half space H2 are formed. The first surface area 2 extends at least substantially within a first plane E7 and the second surface area 3 at least substantially within a second plane E2 parallel to the first plane E7.

In the present description, it is assumed that the first plane E7 is oriented horizontally, with the first surface area 2 pointing downwards and the second surface area 3 pointing upwards. Accordingly, the first surface area 2 delimits the lower half space here, so that the first half space H7 here represents a lower half space and the second half space H2 accordingly an upper half space. In general, however, a different orientation of the light guide element can also be provided; In such a case, the direction or position designations given here must be reinterpreted accordingly.

[0030] The light guide element furthermore has an edge edge region 4 through which the first surface region 2 is connected to the second surface region 3; In the example shown, the marginal edge region 4 extends parallel to the profile axis of the light guide element. In this case, the light guide is provided or configured so that a light is radiated or coupled into the light guide via the edge area 4 and is furthermore at least partially emitted via the first surface area 2 into the first half-space H7, that is to say downwards here. In the example shown, the marginal edge area 4 directly adjoins the plate-shaped partial area 1; with reference to the representation of FIG. 2 on the left side of the plate-shaped partial area 1.

4, a lamp is outlined, here exemplarily in the form of a floor lamp which has the light guide element. The lamp has a lamp base 12 which forms a base for the lamp and and a lamp arm 11 which extends upwards from the lamp base 12 and on which the light guide element is arranged. The luminaire is preferably designed in such a way that the light guide element is oriented at least substantially horizontally when the luminaire is in a state intended for operation. The first surface area 2 points downwards, the second surface area 3 points upwards.

The lamp has a light source 10, here in the form of an LED light source, which is designed and arranged such that a light emitted by the light source 10 as described above enters the edge area 4 of the light guide element in this. Accordingly, the light that has entered is emitted in the further course partly via the first surface area 2 into the lower half-space H7, in the example shown for generating direct illumination, as indicated by an arrow D / R.

[0033] The light guide element furthermore has an edge region 5 lying opposite the edge edge region 4; in the example shown, the edge region 5 extends parallel

to the profile axis of the light guide element. In Fig. 3 a cross-sectional sketch of this edge area 5 is sketched normal to the profile axis. The edge area 5 is designed in such a way that the light rays L7, L2, L3, L4 representing the light, which fall into the edge area 5, are deflected at least predominantly in such a way that they direct the light guide element into the second half-space H? 2, that is to say here leave above. In the case of the luminaire shown in FIG. 4, it can be provided that the light emission above the edge area 5 serves to generate indirect lighting, as indicated by a further arrow / NDI / R.

The light rays L7, L2, L3, L4 thus represent the light emitted by the light source 10. The light beams L7, L2, L3, L4 accordingly run within the plate-shaped partial area 1 with reference to the illustration in FIG. 2, essentially from left to right. Some of the light transmitted to the right emerges downward from the light guide element via the first surface area 2.

Preferably, the plate-shaped partial area 1 of the light guide element and the edge area 5, in particular the entire light guide element, are formed from only one material. In particular, it can be provided that the plate-shaped partial area 1 and the edge area 5, in particular the entire light guide element, are designed to form a coherent piece, that is to say in one piece.

The light guide element is therefore preferably made of a material that has a refractive index n7 that is greater than the refractive index n2 of air. The latter is known to be around 1.00. The light guide element can, for example, be made of PMMA (polymethyl methacrylate), so that in this case the refractive index n7 is approximately 1.49. There is therefore, as is known, a critical angle for total reflection or critical angle a for a light beam that strikes a boundary surface of the light guide within the light guide element, the critical angle a being as follows from the two refractive indices n7? and n2 is dependent: a = arcsin (n2 / n1).

At the right boundary of the plate-shaped partial area 1, the light rays finally enter the edge area 5, as indicated in FIG. 3, and are deflected by the latter. The design of the edge region 5 is such that the light beams L7, L2, L3, L4, which are incident in the edge region 5, are deflected at least predominantly in such a way that they leave the light guide element in the second half space H2, that is to say here directed upwards.

In particular, the edge region 5 can have a surface section 6 which extends between the first plane E7 and the second plane E2 and which is shaped, in particular curved, in such a way that the light beams L7, L2, L3, L4 on the surface section 6 are totally reflected. This prevents the light beams L1, L2, L3, L4 from being refracted at the surface section 6 and subsequently leaving the light guide element here. Such rays could in particular lead to an unwanted glare of a user of the lamp.

As can be seen from FIG. 3, the surface section 6 is convex in the example shown. The plate-shaped part 1 of the light guide element merges here, so to speak, into a "lens area".

In the example shown, the edge region 5 has a protruding region 7 which extends beyond the second plane E2, that is to say here extends upwards. The protruding area 7 extends further to the left with respect to the second plane E2, that is to say in the direction of the peripheral edge area 4 than the curved surface section 6. In the sketch shown in FIG. 3 is the point up to which the protruding area 7 extends to the left, denoted by P7 and the point to which the curved surface section 6 extends to the left by P2. Another point P3 denotes the normal projection of point P7 onto the first plane E7.

The protruding region 7 extends - as indicated in FIG. 3 - by a dimension X further in the direction of the peripheral edge region 4 than the curved surface section 6. The dimension x here corresponds to the distance between the points P2 and P3.

With reference to FIG. 3, the first surface area 2 of the plate-shaped partial area 1 preferably extends by the dimension x further to the right than the second surface area 3, so that an end area 21 is formed by the first surface area 2 extends up to the point P2, that is to the curved surface section 6.

It can thus be achieved that none of the light beams L7, L2, L3, L4 strikes the surface area 6 so steeply that it is broken at this point and thus emerges from the light guide element at this point. In the example shown, dimension x is selected so that the following applies:

x> d: tana,

Where d denotes a thickness of the plate-shaped section 1, in particular the thickness that the plate-shaped part 1 has at its end adjacent to the edge area 5. The thickness d thus corresponds at least essentially to the distance between the first plane E7 and the second plane E2.

This choice of dimension x can ensure that a light beam, which in the cross section shown runs at the critical angle a at point P7, does not interact with the curved surface area 6 after its total reflection, but rather still meets the end region 21 of the first surface region 2. A light beam L5 parallel to this, which passes to the right of point P7, on the other hand, passes into the projecting area 7.

Furthermore, the projecting region 7 preferably has a flank region 8 directed obliquely into the second half space H2, which includes an angle β with the second surface region 3, which is not greater than the sum of 90 ° and the critical angle α. This configuration prevents the light beam L5 mentioned above from interacting with the flank 8.

Furthermore, viewed in the normal cross section, the projecting region 7 of the edge region 5 preferably extends upwards to a point P4, the flank region 8 in particular being able to extend up to this point P4. A "cross-sectional enlargement" is thus formed, so to speak, by the edge region 5, starting from the plate-shaped partial region 1.

The flank region 8, as sketched in FIG. 3, can be designed flat. However, in this embodiment, the flank area 8 is optically ineffective in a partial area adjacent to the second surface area 3, as is evident from the light beam profiles described, so that it can in principle be used, for example, to form a fastening element, for example in the form of a recess, a groove or a screw channel.

In the example shown, the curved surface section 6 merges upwards into a further surface section 9 of the edge region 5, which can also be convex, for example. The shape can be such that the light beams L7, L2, L3, L4 are totally reflected again on the further surface section 9 and are further refracted outwards via the flank region 8. Thus, the light beams L7, L2, L3, L4, when they have left the light guide element, are directed into the upper half-space H2.

In the luminaire outlined in FIG. 4, it is provided that light is radiated into the light guide element only via the edge area 4. Accordingly, the aforementioned light source 10 is provided as the only light source. It is further provided that the edge area 5 forms an outer surface of the lamp. Accordingly, in contrast to the prior art mentioned at the outset, in particular no cover element or frame element or the like is provided. The described design of the edge area 5 makes it possible to ensure, even without a corresponding covering element, that no potentially disturbing or dazzling light emerges here.

Furthermore, a corresponding covering element can also be dispensed with on the two edge sides, which extend normal to the profile axis of the light guide element.

Thus, the light guide element can be quasi frameless, which results in particular with respect to the design options of the lamp.

5 shows a sketch of a further possible design of the edge region 5 of the light guide element and of possible further elements of a corresponding luminaire. In the embodiment shown as an example, a flank area is formed by the flank area 8, which serves to hold a reflective element 30 which is arranged on the second surface area 3 of the light guide element; A particularly effective use of light is made possible by the reflective element 30. Furthermore, the luminaire can also have, for example, a secondary optical element 31 for further influencing the light.

The light guide element is not only suitable for use in a floor lamp. For example, it can also be used advantageously for a pendant lamp.

It is also not imperative that the light output via the first surface area 2 is used to generate direct lighting. For example, the light guide element can be provided rotated by 180 ° in comparison to the orientation shown in FIG. 4, so that the first surface area 2 points upwards. A flat light emission can thus be brought about upwards over the first surface region 2 and downwards over the edge region 5.

Claims (10)

Expectations 1. Light guide element, comprising - a plate-shaped partial area (1), through which a first surface area (2) delimiting a first half-space (H7) and, opposite thereto, a second surface area (3) delimiting a second half-space (H2) are formed, wherein the first surface area (2) is at least substantially within a extends first level (E7) and the second surface area (3) at least essentially Chen within a second level (E2) parallel to the first level (£ 7), - An edge edge area (4) through which the first surface area (2) is connected to the second surface area (3), the light guide being provided for the fact that a light is radiated into the light guide via the edge area area (4) and at least further is partially released into the first half-space (H7) via the first surface area (2), marked by an edge region (5) lying opposite the edge edge region (4), which is designed in such a way that light rays (L7, L2, L3, L4) representing the light that fall into the edge region (5) are deflected at least predominantly in such a way, that they leave the light guide element directed into the second half space (H2). 2. The light guide element as claimed in claim 1, characterized in that the edge region (5) has a surface section (6) which extends between the first plane (E7) and the second plane (E2) and is shaped in this way, in particular with a curved shape, that the light rays (L7, L2, L3, L4) are totally reflected on the surface section (6). 3. Light guide element according to claim 1 or 2, characterized in that the light guide element is designed profile-shaped, wherein the edge region (5) extends parallel to the profile axis. 4. Light guide element according to one of the preceding claims, characterized in that the edge region (5) has a projecting region (7) which extends beyond the second plane (E2). 5. The light guide element according to claim 4, characterized in that the projecting region (7) extends by a dimension (x) further in the direction of the peripheral edge region (4) than the surface section (6). 6. The light guide element according to claim 5, characterized in that the following applies to the dimension (x): x> d-tan a, where x denotes the dimension, d is a thickness of the plate-shaped partial region (1) and a is a critical angle that is depending on the refractive index (n7) of a material of the light guide and the refractive index (n2) of air. 7. The light guide element according to claim 6, characterized in that the projecting region (7) has a flank region (8) directed obliquely into the second half space (H2), which includes an angle (β) with the second surface region (3) that is not is greater than the sum of 90 ° and the critical angle (0). 8. Light guide element according to one of the preceding claims, characterized in that the plate-shaped partial area (1) and the edge area (5) are formed from only one material. 9. Light guide element according to one of the preceding claims, characterized in that the plate-shaped partial area (1) and the edge area (5) are designed to form a continuous piece or in one piece. 10. Luminaire, comprising - a light guide element according to one of the preceding claims, - a light source (10), in particular an LED light source, which is designed and arranged in such a way that a light emitted by the light source (10) as provided over the edge area ( 4) the light guide element enters this. 5 sheets of drawings