WO2013050340A1

WO2013050340A1 - Light emitting device for use in a display device

Info

Publication number: WO2013050340A1
Application number: PCT/EP2012/069402
Authority: WO
Inventors: Filip Marcel Denise Bruyneel; Lieve Lea Andrea Lanoye; Benoit Didier Raphael CATTEAU
Original assignee: Tp Vision Holding B.V.
Priority date: 2011-10-04
Filing date: 2012-10-02
Publication date: 2013-04-11

Abstract

A LED device for use in association with a TV having ambient light functionality is provided. The LED device comprises a LED light source and a housing at least partly surrounding the LED light source. The housing has an asymmetrical geometricalshape, at least part thereof being configured to encounter or obstruct a portion of the light emitted from the LED light source, whereby the light exiting the LED device has an asymmetrical light beam shape.

Description

Light emitting device for use in a display device

Field of the Invention

This invention pertains in general to the field of light emitting devices, such as

Light Emitting Diode (LED) devices. In particular the invention relates to an improved LED device suitable for use in association with a display device having ambient light functionality. Background of the Invention

Display systems for enhanced viewing experience when watching video shown on a display device, such as a TV, by using light sources for projecting ambient light are known in the art.

A particularly interesting application is to project the ambient light on a wall using ambient light sources surrounding the display device and/or projecting the ambient light towards a viewer.

Typically, a display device having ambient lighting functionality is a fiat TV, which may hang on a surface, such as a wall, or placed in front of the surface. The display device may be provided with ambient light sources, such as Light Emitting Diodes, located adjacent to a display area or screen being capable of displaying diffuse light correlated to the images or video content presented on the display area. In use, the ambient light sources may emit ambient light towards a surface behind the display device and/or towards a viewer in front of the display device.

Two commonly used solutions to project ambient light is by using either top emitting LEDs or side emitting LEDs. Usually the top or side emitting LED packages are mounted on the backside of the TV on or adjacent to the printed circuit board (PCB) in the vicinity TV frame. Fig. la shows a side view of a side emitting LED 11 mounted on a PCB 12 of a TV, while Fig. lb illustrates a side view of a top emitting LED 13 mounted on a PCB 13 of the TV. Without reflecting the ambient light emitted from the side or top emitting LEDs, a major part of the emitted light will not be projected onto the wall or surface 14 behind the TV. In order to solve this problem reflectors 15 or light guides may be used to direct the light towards the wall or surface, as is schematically illustrated in Figs, lc and Id. However, using light guides or reflectors not only increases the costs involved but also results in an undesirably increased bezel width or thickness for TV sets having the ambient light functionality.

Hence, an improved light emitting device for emitting light and being suitable for use in association with a display device having ambient light functionality would be advantageous.

Summary of the Invention

According to an aspect, a light emitting device for emitting light originating from light emitted by a light source having an optical axis is provided. The light emitted by the light source, when unobstructed, has a first light beam shape in relation to the optical axis. The light emitting device comprises a housing at least partly surrounding the light source. The housing has an asymmetrical geometrical shape in relation to the optical axis. At least part of the asymmetrical geometrical shape is arranged to encounter or obstruct a portion of the light emitted by the light source, such that the light emitted by the light emitting device has an asymmetrical light beam shape in relation to the optical axis. The asymmetrical light beam shape is different from the first light beam shape.

According to another aspect a housing for use in a light emitting device having a light source is provided. The light source having an optical axis, wherein the light emitted by the light source, when unobstructed, has a first light beam shape in relation to the optical axis. The housing is configured to at least partly surrounding the light source (33), in use. Moreover, the housing has an asymmetrical geometrical shape, wherein the asymmetrical geometrical shape is asymmetrical in relation to the optical axis, in use. At least part of the asymmetrical geometrical shape is configured to encounter or obstruct a portion of the light emitted by the light source, such that the light emitted by the light emitting device and exiting the housing, in use, has an asymmetrical light beam shape in relation to the optical axis. The asymmetrical light beam shape is different from the first light beam shape.

An advantage of the LED device according to the embodiments disclosed herein is that no external optical components such as reflectors, lenses, prisms or light guides need to be used in order to direct the ambient light in the desired direction. Instead the geometry of the housing of the LED device is configured to guide the light in the desired direction.

The LED device according to some embodiments, when used in association with a display device having ambient light functionality, allows for a reduction of the mechanical volume of the display device system, as a consequence of less used components.

Moreover, the reduced number of required components leads to a reduction of costs.

Furthermore, the LED device according to some embodiments, allow for improved optical performance compared to commonly known ambient light systems, by avoiding the optical artifacts associated with the no more needed optical

components of current solutions. For example, the LED device according to some embodiments may eliminate the need of using a commonly known diffuser to spread or scatter the light emitted. This allows for a diffuserless design, resulting in fewer components, lower cost, lower losses, and a more compact design. Furthermore, this allows for less cooling requirements since the efficiency is increased.

A further advantage of the LED device, when used in association with a display device having ambient light functionality, is that it allows for increased efficiency of the display device system, by reducing the loss of light or energy resulting from the number of components as opposed to current solutions requiring more components.

Brief Description of the Drawings

These and other aspects, features and advantages of which the invention is capable of will be apparent and elucidated from the following description of embodiments, reference being made to the accompanying drawings, in which

Figs, la to Id schematically show commonly used solution for displaying ambient light in association with a TV set;

Fig. 2a is an illustration schematically showing the symmetrical light beam shape of a commonly known LED package as seen from a bottom view;

Fig. 2b is an illustration schematically showing an asymmetrical light beam shape of the LED device according to an embodiment as seen from a bottom view;

Figs. 3 to 10 each illustrate a cross sectional view of a LED device according to an embodiment; Fig. 11 illustrates a front view of a LED device according to an embodiment; Figs. 12a to 12c each illustrates a 3D view of a LED device according to an embodiment;

Figs. 13 and 14 each illustrate a cross sectional view of a LED device according to an embodiment; and

Fig. 15 illustrates a 3D view of a LED device according to an embodiment.

Description of embodiments

Several embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in order for those skilled in the art to be able to carry out the invention.

An idea of the present invention is to provide a light emitting device, such as a LED device, which is more suitable for use as an ambient light source in association with a display device than that of commonly known solutions. This is achieved by providing a LED device having a housing geometrically configured in an asymmetrical way in relation to and/or around the LED light source, such that there is no longer any need for an external reflector (i.e. a reflector not being part of the LED device per se) or light guide to direct the emitted ambient light towards a wall or surface behind the display device.

More particularly, the housing of the LED device onto which the LED light source, such as LED die, optionally is attached is configured to direct at least part of the light emitted from the LED such that the light exiting the LED device has an asymmetrical shape in relation to and/or around the normal at the midpoint of the LED die.

In other words the housing of the LED device is arranged to change the essentially symmetrically emitted light from the LED light source into a light beam being asymmetrical before the light exits the LED device.

In other words, the housing of the LED device is configured in such a way that the general direction of the light exiting the LED device is different than the optical axis of the light source around which light is emitted from the LED light source in the LED device. The term "display system" used throughout this description is intended to mean a display system comprising a "display device", such as a TV, having ambient light functionality, and the "LED device" for emitting the ambient light. It should be appreciated that the term "light" as used herein is not limited only to electromagnetic radiation within the visible spectrum wavelengths. Hence, light source of the light emitting device may be configured to emit light at least partly comprising wavelengths outside the visible spectrum, such as ultra violet (UV) light, near infrared (NIR) light, or infrared (IR) light. The material of the housing is selected such that it has a suitable reflection coefficient based on the wavelength spectrum of the light source being equipped in the housing.

Fig. 2a schematically shows a commonly known side or top emitting LED package 20a seen from behind. The LED package 20a emits light symmetrically around the normal at the midpoint of the LED package 20a. The resulting symmetrical, or essentially symmetrical, light beam shape 21a, observed at a plane located at a distance from the LED package 20a and perpendicularly arranged to the main optical axis, is shown as a circle in Fig. 2a. Hence, when the light emitted from the LED package 20a is unobstructed this will result in an essentially symmetrical light beam shape in relation to the optical axis of the LED package 20a.

Fig. 2b schematically illustrates a LED device 20b according to an embodiment seen from behind in the same manner as in Fig. 2a. Since the LED device, and in particular the housing thereof, is configured to change the light beam shape, e.g.

symmetrical light beam shape, of the emitted light before exiting the LED device, the resulting light beam shape 21b will be asymmetrical around the normal at the midpoint of the LED device 20b, or optical axis thereof, as is shown in Fig. 2b as an elongated shape. Hence, the housing is configured to encounter or obstruct at least part of the light emitted by the light source or LED package in an asymmetrical manner thereby resulting in an asymmetrical light beam shape in relation to the optical axis.

The term "light beam shape", "first light beam shape" or "asymmetrical light beam shape" as mentioned herein may be interpreted as the shape of the light when or as observed at a plane perpendicularly arranged to the optical axis, such as main optical axis, of the light source. Furthermore, it should be appreciated that the "asymmetrical light beam shape" refers to the shape of the light, at the plane perpendicularly arranged to the optical axis of the light source of the LED device, leaving or exiting the LED device. Hence, the imaginary plane is considered being located along the optical axis outside or beyond the outer boundary of the LED device. Although the LED device 20b has the same cross-sectional shape as the commonly known LED package 20a, it should be appreciated that the configuration of the LED device 20b is structurally and functionally different to that of the

schematically illustrated and commonly known LED package 20a, and that these structurally and functionally different features results in the asymmetrical light beam shape.

Fig. 3 illustrates a LED device 30 according to an embodiment. The LED device 30 comprises a housing 31. The housing comprises a seat 32 onto which a LED light source or LED die 33 may be mounted. Although not shown, an electrical circuit or wiring for providing the LED light source 33, when mounted into the seat 32, with power is provided in the housing. Any suitable known electrical circuit or wiring may be used in this regard, such as a Plastic Leaded Chip Carrier (PLCC).

The housing is preferably made of a plastic material, allowing for the housing to be molded into the desired shape. Optionally the material of the housing may be a ceramic.

The material of the housing is preferably selected having material characteristics influencing light incident onto a surface thereof, whereby the light exiting the LED device may be directed in a desired direction.

For example, the material of the housing may be selected to absorb at least part of the incident light, thereby preventing light to exit the LED device in a certain angle by absorption of a part thereof. Such material may have a darker color improving the light absorbing characteristics of light having wavelengths within the visible spectrum.

Alternatively, the material of the housing may be selected to be reflective, thereby allowing incident light to be reflected upon hitting a surface thereof. Such material may have a bright or white color allowing for desired reflection of light having wavelengths within the visible spectrum.

Optionally, the material of the housing may be coated with a further material capable of improving the light directing functionality even further, wherein the further material e.g. may have improved absorptive or reflective characteristics.

The LED device 30 may be mounted onto a support surface 34, such as a PCB for facilitating the electrical connection to the LED light source 33.

The housing 31 comprises at least one sidewall 35 extending from the seat 32 in a direction essentially parallel with the optical axis of the LED light source 33. The configuration of the sidewall 35 is such that the height H, h of the sidewall 35 in relation to the seat differs between at least two positions along the sidewall 35. From Fig. 3 it may be observed that the sidewall 35 has a first height H on the right side of the LED light source 33, while it has a second height h on the opposite side of the LED light source 33. In the current embodiment the second height is smaller than the first height H. This asymmetrical geometry of the sidewall 35 allows for directing the light emitted by the LED light source 33 in asymmetrical way. As may be observed from Fig. 3, the sidewall 35 on the right side of the LED light source 33 will reflect a greater portion of the light arrays from the LED light source due to its higher height. This means that the light beam shape exiting the LED light source 30 will be shifted or directed more to the left than if the height of the sidewall to the right would be equal to the height h of the sidewall to the left.

As may be observed from Fig. 3 the LED light source 33 is mounted to the housing seat 32 essentially parallel to the underlying surface 34, similar to existing top emitting LEDs as illustrated in Figs, lb and Id.

Fig. 4 illustrates another embodiment of the LED device 40 according to an embodiment. The LED device 40 has essentially the same geometry as the LED device 30 of Fig. 3, however the housing 41 of the LED device 40 is configured to be attached to the underlying surface 34 on a different outer side than that of the housing 31 of the LED device 30.

As may be observed from Fig. 4 the LED light source 33 is mounted to the housing seat 32 essentially orthogonal to the underlying surface 34, similar to existing side emitting LEDs as illustrated in Figs, la and lc.

Fig. 5 illustrates an alternative LED device 50 according to an embodiment. The LED device 50 comprises a housing 51 having a seat 52 oriented at an angle δ, such as but not limited to around 45 degrees, in relation to the underlying surface 34. A LED light source 33 is mounted to the seat 52, e.g. in the same way as in the previous embodiments. As may be observed from Fig. 5, the housing comprises a sidewall 55 extending at least partly around the seat 52 onto which the LED light source 33 is mounted. The sidewall has a first side facing the LED light source 33, and a second side opposite the first side. The first side of the sidewall 51 has a first height hi . In order to save space and material one side of the sidewall may be chamfered or an part thereof being chambered or phased off, thereby reducing the component costs and minimizing the required space for the LED device. In this way, the first side may have a different height than the height h2 of the second side, in relation to the plane of the seat 52. As may be observed from Fig. 5 the second height h2 on the left side of the LED light source 33 is less than the first height hi on the left side of the LED light source 33. Due to the asymmetrical geometrical configuration of the housing 51, the first height and second height may each differ along the extension of the sidewall. In Fig. 5 it may be observed that the first side of the sidewall, to the right of the LED light source 33 has a height HI that differs from the height hi of the first side of the sidewall to the left of the LED light source 33, thereby defining a chamfered end. In this embodiment the height HI is larger than hi . Furthermore, it may be observed that the second height H2 of the sidewall to the right of the LED light source 33 differs from the second height h2 of the sidewall to the left of the LED light source 33. In this case the height H2 is larger than height h2. In fact, in this alternative embodiment, the second height h2 is less than height hi, which is less than height H2, which is less than height HI . However, it should be appreciated that this intrinsic relation between the heights hi, h2, HI, and H2 may differ depending on the geometrical configuration of the housing. Hence, by chamfering at least one part of the sidewall the size as well as material costs of the housing may be reduced. Moreover, although the housing seat 52 is arranged at an angle δ in relation to the underlying surface 34, it is asymmetrically configured by varying height along the extension of the sidewall(s) at least partly surrounding the LED light source 33.

It should be appreciated that although the sidewalls of the LED device 30 or 40 of Figs. 3 and 4 are not provided with a chamfered sidewall in the same manner as the LED device 50 of Fig. 5, this is also a possible embodiment.

Depending on the type of application the angle δ may be varied for optimal optical performance. For example, when the LED device is used in a TV, the angle δ may be set having in mind the lateral distance in relation to outer edge of the TV from which the LED device will be positioned or arranged, and the intended distance between the backside of the TV and the surface onto which the ambient light is to be directed in use. Hence, the farther away from the outer edge the LED device is positioned or arranged the larger the angle δ may be selected to be, in order for the light emitted by the LED device to be directed towards the suitable area of a surface located behind the TV and surrounding the outer edge. The closer the LED device is positioned or arranged towards the outer edge the smaller the angle δ may be set to be. Hence, any angle between 0 degrees (top emitting) and 90 degrees (side emitting) may be selected, such as 1 to 89, etc.

In an embodiment, the angle δ is smaller than 45 degrees.

In an embodiment, the angle δ is larger than 45 degrees.

In an embodiment, the angle δ is zero or essentially 0.

Accordingly, in addition to the asymmetrical geometrical shape of the housing resulting in an asymmetrical light shape of the light exiting the LED device, by configuring the LED light source at an angle δ, this further improves the functionality of directing the emitted light in the desired direction. However, it should be appreciated that the angle δ per se has no impact on the light beam shape, but rather the direction in which the light is originally emitted.

Fig. 6 illustrates a LED device 60 according to an embodiment. The LED device 60 has essentially the same geometry as the LED device 50 of Fig. 5, however the housing 61 of the LED device 60 is configured to be attached to the underlying surface 34 on a different outer side than that of the housing 31 of the LED device 30.

While the previous embodiments address the geometrical asymmetrical configuration of the housing by varying height of the sidewall(s) at least partly surrounding the LED light source, another approach which may be used solely or in combination with varying height of the sidewall(s) is by varying the angle a between the first side of the sidewall in relation to the seat 32 plane.

Fig. 7 illustrates a LED device 70 according to an embodiment. In addition to the varying heights, e.g. between the sidewall to the left and the sidewall to the right as previously has been disclosed, the side wall of the housing 71 to the right of the LED light source 33 is provided at an first angle a in relation to the plane of the seat, while the sidewall to the right of the sidewall is provided at second angle β in relation the seat plane. In this example, the second angle β is less than first angle a. By varying the angle α, β along the extension of the sidewall(s) at least partly surrounding the LED light source 33, this will also result in an asymmetrical light beam shape exiting the LED device 70.

In an embodiment the height of the sidewall in relation to the seat along the extension of the sidewall(s) at least partly surrounding the LED light source, may be essentially the same or identical while the angle α, β along the sidewall may vary in order to create an asymmetrical light beam shape exiting the LED device.

As may be observed from Fig. 7, the seat is arranged at an angle δ, in the same manner as in Fig. 5. However in this embodiment, the angle δ is less than 45 degrees, such as between 20 and 30 degrees.

Fig. 8 illustrates a LED device 80 according to an embodiment. The LED device 80 is similar to that of Fig. 7, however the housing 81 is configured to be mounted onto the underlying surface 34 on a different side than that of the housing 71 of Fig. 7.

Fig. 9 illustrates a LED device 90 according to a further embodiment, similar to that of the LED device 50 of Fig. 5. However, in the LED device 90 a part 92 of the housing facing the underlying surface 34 is chamfered to save space and component costs.

Fig. 10 illustrated a LED device 100 according to an embodiment. The LED device 100 is similar to the LED device 60 of Fig. 6, however wherein the housing 101 of the LED device 100 is configured to be mounted to the underlying surface 34 at a different side than that of housing 61 of Fig. 6. Furthermore, a part 102 of the side facing the underlying surface 34 is chamfered, similar to that of Fig. 9.

Although the first angle a, second angle β, height hi, height h2, height HI, height H2, in some embodiments above have been used in combination, it should be appreciated that each of these parameters having impact on the asymmetrical geometry of housing of the LED device, may be incorporated solely according to an embodiment. Moreover, it should be appreciated any combination of these parameters is covered in some embodiments. These parameters may be referred to as asymmetry parameters since they each may affect the asymmetrical geometry of the housing of the LED device. Moreover, by providing the housing in some embodiments with a seat having a plane at an angle δ in relation to the underlying surface the optical performance of the LED device may even further be improved, by facilitating the direction of the asymmetrical light beam shape. Accordingly, angle δ of the housing may be tailor made for each application to optimize the optical performance.

Another option to improve the formation of the desired asymmetrical light beam shape of the light exiting the LED device is by mounting the LED light source in the housing closer to one of the sidewalls, or at a position closer to the sidewall on one side of the LED light source than the other. Hence, it is not required that the LED light source is provided at the midpoint or centerline of the housing, or concentrically for that matter.

Hence, the distance at which the LED light source is provided from one of the sidewalls, may be selected to allow for the desired optical effect.

In an embodiment, the LED device comprises three LED light sources, one red

LED light source, one green LED light source, and one blue LED light source. In this way, the emitted light from the LED device conforms to the RGB standard.

The number and spectral characteristics of LED light sources provided in the LED device may differ depending on the application. Hence, within the scope of the invention the asymmetrically geometrically shaped housing may be configured to incorporate any number of LED light sources, emitting light having any wavelength, and suitable for emitting light in accordance with any possible standard. Fig. 11 illustrates a front view of the LED device 110 according to an embodiment. The LED device 110 may correspond to the LED device 30, 40, 50, 60, 70, 80, 90, 100 in accordance with any one of the previously disclosed embodiments. The LED device 111 comprises three LED light sources. A first of the LED light sources, denoted R in Fig. 1 1, is configured to emit light in the red wavelength spectrum. A second of the LED light sources, denoted G in Fig. 11, is configured to emit light in the green wavelength spectrum. The third LED light source, denoted B in Fig. 1 1, is configured to emit light in the blue wavelength spectrum. Each of the LED light sources, R, G; and B, are provided onto a seat 111 of a housing 112. The asymmetrical geometrical shape of the housing 112 is not easily observable in Fig. 11, as the front view is defined at a plane essentially parallel to the housing seat 111. Electrical connectors 113 connected to each of the LED light sources R, G, and B (not shown) are provided at the side of the housing in use facing the underlying surface for connection thereto.

The housing according to some embodiments is configured such that the electrical connectors 113 for connection to the LED light source are only provided at a single side or face of the housing (as shown in Fig. 11). This facilitates the connection of the LED device to the underlying surface, while minimizing the potential errors associated with the mounting and subsequent operation of the LED device.

In an embodiment the width L2 of the LED device comprising three LED light sources, may be approximately 45mm, such as from 35mm to 55mm. In an embodiment the height LI of the LED device comprising three LED light sources, when mounted onto an underlying surface in use may be approximately 25mm, such as from 15mm to 35mm.

However, it should be appreciated that any size, preferably as small as possible, may be utilized within the scope of the invention. Many prior art solution are bulky which makes the not suitable for use in association with a display device having ambient light functionality.

Figs. 12a and 12b each illustrates the LED device of Fig. 9 or Fig. 10 seen at an angle, being provided with three LED light source in the same manner as in Fig. 11. As may be observed from Fig. 12b, the LED device has chamfered ends, resulting in an essentially octagonal cross section.

Fig. 12c illustrates a LED device according to another embodiment, having a hexagonal cross section. Hence, the LED device of Fig. 12c illustrates may be considered being less chamfered than the LED device of Fig. 12b.

In an embodiment the housing of the LED device is made integral with the PCB of the TV. In this way the LED light source may be directly connected to the PCB of the TV, thereby reducing the space needed for the display system.

In the embodiments above the light source 33 is positioned or arranged onto a seat of the housing. However, to allow for the technical effect of an asymmetrical light beam shape exiting the LED device, it is not required for the light source 33 to be mounted on a seat of the housing.

For example, the LED device according to some embodiment may be configured to operate in so called chip on board devices related to the commonly known chip on board technology. In this case the LED light source(s), i.e. LED die(s), is directly mounted onto the underlying PCB, without being mounted in a housing seat, in contrast to the previous embodiments.

The top surface of the PCB contains resin residues, such as silicone or epoxy, and in order to prevent these resins to flow all over the PCB, some small barriers are positioned or arranged around the LED die.

In an embodiment, these barriers are provided in an asymmetrical geometrical shape in relation to and/or around the LED die.

Accordingly, according to an embodiment the housing comprises or consists of at least one barrier having an asymmetrical geometrical shape, for reflecting light emitted from the LED dies, such that the light exiting the LED device has an asymmetrical light beam shape.

Figs. 13 and 14 each illustrates a LED device suitable for chip on board applicability.

Fig. 13 illustrates a cross section of a LED device 130 having a light source 33 directly mounted onto the underlying surface 32. In this embodiment the housing 131, 132 comprises a sidewall 111, 112 at least partly surrounding the light source 33 but no integral seat onto which the light source 33 may be mounted, thereby reducing the required space. The housing acts as a barrier to prevent resins situated on the underlying surface to flow and interfere with the LED die 33. It may be observed from Fig. 13, that the height HI of the sidewall 131 to the left of the light source 33 is smaller than the height H2 of the sidewall 132 to the right of the light source 33, thereby forming the light emitted from the light source into an asymmetrical light beam shape when exiting the housing 131, 132. It may be noted that Fig. 11 is similar to that of Fig. 3, however without the LED device being provided with a seat 32.

In a similar manner, the housing as illustrated in each of the embodiments of Fig. 4 to Fig. 10 may be provided without a seat according to some embodiments. Hence, the technical effect of providing a symmetrical light beam shape exiting the LED device is still possible without arranging a seat in the housing, as shown in Fig. 13, and 14.

Fig. 14 illustrates a cross section of another LED device 140 according to an embodiment, suitable for use in a chip on board application. In Fig. 14, the sidewall 142 of the housing 141, 142 to the right is inclined thereby improving the direction of the asymmetrical light beam shape to the left in the figure. In the same manner as in Fig. 13, the height h of the sidewall to the left 141 of the housing 141, 142 is smaller than the height H of the sidewall 142 to the right, thereby even further contributing to the formation of an asymmetrical light beam shape exiting the LED device.

It should be appreciated that by providing the housing or the barrier at least partly surrounding the LED light source in an asymmetrical geometrical shape, there is no need for an external reflector. This advantage is also evident when the LED device is configured for use in a chip on board application. It should be appreciated that although the LED device according to some embodiments for illustrative purposes is mounted onto a PCB of a TV, the present invention is not limited to this application. Accordingly, the LED device may in accordance with another embodiment be mounted onto any suitable surface, for emitting light having an asymmetrical light beam shape.

Although the shape of the seat 111 in Fig. 11 is essentially rectangular, whereby the sidewalls extends around the LED light sources in a rectangular fashion when observed from a front view, this embodiment should not be considered limiting for the invention.

The cavity defined by the sidewall extending from the underlying surface or seat to the end of the sidewalls, may have any three dimensional shape, as long as the sidewall of the housing is at least partly asymmetric in relation to and/or around the optical axis of the LED light source. Hence, seen from a front view the shape may appear essentially round, square shaped, rectangular, triangular or any other shape, suitable for the purposes of the desired application.

Fig. 15 illustrates a 3D view of a LED device 150 according to an embodiment, having an essentially hollow square or rectangular shape when observed from a top view, but with the rear side wall 152 having a height H being larger than the height h of a front side wall 151. The light source of the LED device is not shown. Accordingly, from the height h and upwards, the housing 150 is asymmetrical in relation to and/or around the optical axis, since whereas there is no front sidewall over height h on the front side, the rear sidewall extends up to height H. In this way part of the light emitted from the at least one light source (not shown) will on one side of the light source encounter a sidewall 152 up to a height H, while on the other side encounter a sidewall 151 only up to a height h, wherein height h is smaller that height H. This allows for an asymmetrical light beam shape exiting the LED device.

In an embodiment, the LED device is incorporated in a display device having ambient light functionality, for emitting ambient light.

It should be appreciated that although chamfering the sidewall may reduce the size and hence material costs of the housing, it is not always preferred. Hence, in some embodiments it is not necessary to chamfer any part of the housing. The extent of chamfering depends on the intended application.

Although the LED device in some embodiments has been described as suitable for use in association with a display device, optionally having ambient light functionality, the LED device as described herein should not be considered limited only to that specific type of application. As such, the LED device according to some embodiments may be operated independently of any display device. For example, the LED device may be utilized in association with a device, not being a display device, having ambient light

functionality.

The LED device according to some embodiments may be operated independent of an ambient light functionality.

The LED device, according to some embodiments, may be used as an improved light source applicable to any application wherein light sources are required, and preferably in such applications wherein an asymmetrical light beam shape is desired. For example, the LED device may be used as a light source arranged to direct the light emitted therefrom in a certain direction without the need of a mechanical reflector. Hence, the dimensions of the LED device may be kept compact.

According to a further example, the LED device, according to some

embodiments, may be provided in a lamp unit, such as a desk lamp unit or in a lamp armature provided in the ceiling. Furthermore, a combination of LED devices according to some embodiments is possible, at least two of which provide for different asymmetrical light beam shapes. In this way the out coupling angle of the lamp(s) could be increased.

Accordingly, no additional reflectors and/or lenses are needed to increase the out coupling angle which reduces the required mechanical dimensions as well as increases the overall efficiency.

Although the present invention has been described above with reference to specific embodiments in which the light emitting device is a LED device, and the light source is a LED light source or die, it should be appreciated that the present invention is not limited to the specific use of light emitting diodes. Hence, other types of light sources are equally possible within the scope of this invention. Irrespective of the used light source, the housing of all embodiments is provided with an asymmetric geometry as disclosed above, which is suitable to direct the light emitted from the light source equipped in the housing in an asymmetrical way, hence resulting in an asymmetrical light beam shape exiting the light emitting device.

Claims

CLAIMS:

1. A light emitting device (20b, 30, 40, 50, 60, 70, 80, 90, 100) for emitting light originating from light emitted by a light source (33) having an optical axis, wherein the light emitted by the light source (33), when unobstructed, has a first light beam shape in relation to the optical axis, comprising

a housing (31, 41, 51, 61, 71, 81, 91, 101, 111, 112, 131, 132, 141, 142, 151, 152) at least partly surrounding the light source (33),

the housing (31, 41, 51, 61, 71, 81, 91, 101, 111, 112, 131, 132, 141, 142, 151, 152) having an asymmetrical geometrical shape in relation to the optical axis, wherein at least part of the asymmetrical geometrical shape is arranged to encounter or obstruct a portion of the light emitted by the light source (33), such that the light emitted by the light emitting device (20b, 30, 40, 50, 60, 70, 80, 90, 100) has an asymmetrical light beam shape in relation to the optical axis, the asymmetrical light beam shape being different from the first light beam shape.

2. The light emitting device according to claim 1, wherein the housing comprises a sidewall having a varying height (h, H) along its extension.

3. The light emitting device according to claim 1, wherein the housing comprises at least two sidewalls having different heights (h, H).

4. The light emitting device according to claim 1, wherein the housing comprises a seat (32) for receiving the light source (33).

5. The light emitting device according to claim 4, wherein the housing (31) comprises at least one sidewall (35) extending from the seat (32) in a direction essentially parallel with the optical axis of the light source.

6. The light emitting device according to claim 4, wherein the seat (32) is arranged at an angle (δ) in relation to a support surface (34) to which the housing (51, 61, 71, 81, 91, 101) is mounted, in use.

7. The light emitting device according to claim 4, wherein the seat (32) is arranged in parallel with a support surface (34) to which the housing (51, 61, 71, 81, 91, 101) is mounted in use.

8. The light emitting device according to claim 4, wherein the seat (32) is orthogonally arranged in relation to a support surface (34) to which the housing (51, 61, 71, 81, 91, 101) is mounted in use.

9. The light emitting device according to claim 1, wherein the housing is made of a material configured to absorb at least part of the light emitted by the light source and incident onto a surface thereof.

10. The light emitting device according to claim 1, wherein the housing is made of a material configured to reflect at least part of the light emitted by the light source and incident onto a surface thereof.

11. The light emitting device according to claim 1 , wherein the housing comprises a sidewall having a first side facing the light source (33) and a second side opposite the first side, wherein the first side of the sidewall (51) has a first height (hi, HI), and wherein the second side has a second height (h2, H2), wherein the first height (hi, HI) is different from the second height (h2, H2).

12. The light emitting device according to claim 1, wherein the housing comprises a sidewall (71, 81, 142) which along its extension is arranged at an angle (α, β) different from essentially 90 degrees in relation to a surface or seat onto which the light source (33) is mounted, in use.

13. The light emitting device according to claim 1, wherein a part (92, 102) of the housing facing the support surface (34) in use is chamfered at an angle.

14. The light emitting device according to claim 1 connected to a display device having ambient light functionality for emitting ambient light.

15. A housing (31, 41, 51, 61, 71, 81, 91, 101, 112, 111, 131, 132, 141, 142, 150) for use in a light emitting device having a light source (33), the light source (33) having an optical axis, wherein the light emitted by the light source (33), when unobstructed, has a first light beam shape in relation to the optical axis,

wherein the housing is configured to at least partly surrounding the light source

(33), in use,

the housing having an asymmetrical geometrical shape, the asymmetrical geometrical shape being asymmetrical in relation to the optical axis, in use,

wherein at least part of the asymmetrical geometrical shape is configured to encounter or obstruct a portion of the light emitted by the light source (33), such that the light emitted by the light emitting device (20b, 30, 40, 50, 60, 70, 80, 90, 100) and exiting the housing, in use, has an asymmetrical light beam shape in relation to the optical axis, the asymmetrical light beam shape being different from the first light beam shape.