WO2012032436A1

WO2012032436A1 - Segmented illumination system

Info

Publication number: WO2012032436A1
Application number: PCT/IB2011/053788
Authority: WO
Inventors: Lieve Lea Andrea Lanoye; Filip Marcel Denise Bruyneel; Wim Housen
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2010-09-08
Filing date: 2011-08-30
Publication date: 2012-03-15

Abstract

The present invention pertains to an illumination system (10) with the capability of producing illuminated segments from a single collection of light sources. The illumination system comprises at least a first light source (11a) and a second light source (11b) arranged side-by- side in a single array, and a semi-transparent refractive sheet (12) positioned between the light sources (11) and the region (100). A display device having ambient light capability is also provided, wherein the ambient light capability is provided by the illumination system (10).

Description

Segmented illumination system

FIELD OF THE INVENTION

The present invention pertains to the field of illumination systems. In particular, the present invention pertains to an illumination system with the capability of producing illuminated segments from a single collection of light sources.

BACKGROUND OF THE INVENTION

Illumination systems for producing separate illuminated segments, such as for enhanced viewing experience when watching video shown on a display device, for example a TV, by using different combinations of light sources (11) and refractive elements for projecting light onto a surface to create illuminated segments, are known in the art.

A particularly interesting application of illuminated segments is to project light as ambient light on a wall using ambient light sources (11) surrounding the display device and/or projecting the ambient light towards a viewer.

Typically, a display device having ambient lighting functionality is a flat 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 (11), 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 (11) may emit ambient light towards a surface behind the display device and/or towards a viewer in front of the display device.

Fig. 1 shows an illumination system according to prior art, wherein two different light sources (11) A are mounted on a circuit board C, which in turn is mounted on a support S. The light from the light sources (11) is refracted by a refractive unit R to illuminate a region behind the refractive unit R.

In order to control the refraction of the light sources (11), the mutual position of the light sources (11) A may be varied, or the light sources (11) A may be of different kinds. Fig. 1A show an example of prior art with different light sources (11) Al, A2, mounted on the same circuit board C. Fig. IB show an example of a prior art where the light sources (11) A are positioned on two different circuit boards CI, C2.

A problem with the solutions according to prior art is that they are bulky, since two different light sources (11) Al, A2, or two different circuit boards CI, C2 needs to be covered by the refractive unit R. Furthermore, the system is complex and which increase production costs and the likelihood of system failure.

Hence, there is a need for an improved illumination system.

SUMMARY OF THE INVENTION

Accordingly, the present invention preferably seeks to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination and solves at least the above mentioned problems by providing an illumination system according to the appended patent claims.

An object of the invention is to provide a compact illumination system.

In an aspect, an illumination system for segmented illumination of a region is provided. The system comprises at least a first light source and a second light source arranged side-by-side in a single array. The system also comprises a semi-transparent refractive sheet, positioned between the light sources and the region. The semi-transparent refractive sheet is composed of at least a first area and second area, wherein each area, depending on the incident light angle from each of the light sources, is configured to refract a first part of the light emitted from each of the light sources into at least one illuminated segment towards the region. Each area is also configured to reflect a second part of the light emitted from each of the light sources in a direction away from the region. When a first part of incident light from a light source (11a, 1 lb) is refracted by the first area, the first area is configured to reflect incident light from a neighboring light source, and when a first part of incident light from a light source is refracted by the second area, the second area is configured to reflect incident light from a neighboring light source.

In an aspect, a display device having ambient light capability is provided, wherein the ambient light capability is provided by an illumination system according to an aspect.

An advantage of the illumination system is that only one array of light sources is needed, which saves space. Another advantage of the illumination system is that the number of components needed is decreased, which is cost effective.

Another advantage with the illumination system is that no collimator parts are needed, which saves space.

Other embodiments and advantages will be disclosed in the following.

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 of the present invention, reference being made to the accompanying drawings, in which

Figs. 1A and IB are an illustration of an illumination system according to prior art, included for comparative reasons;

Fig. 2 is an illustration an illumination system according to an embodiment;

Fig. 3 is an illustration of a refractive principle according to an embodiment;

Figs. 4 and 5 are illustrations of an illumination system according to embodiments;

Figs. 6A and 6B are a schematic overview of the refraction of light according to an embodiment;

Fig. 7 is an illustration an illumination system according to an embodiment; Fig. 8 is an illustration of a refractive sheet according to an embodiment; and Fig. 9 is an illustration of a display device according to an embodiment.

DESCRIPTION OF EMBODIMENTS

The following description focuses on embodiments applicable to an ambient display device wherein the ambient light sources 11 are provided by the illumination system.

An idea of the present invention is to use a semi-transparent refractive sheet 12, which is only semi-transparent to the light from a light source 11. Thus, part of the light is refracted in the desired direction and part of the light is reflected so that it substantially does not penetrate the refractive sheet 12.

In an embodiment according to Fig. 2 an illumination system 10 for segmented illumination of a region 100, such as a wall, is provided. The system 10 comprises a light source 11 and a semi-transparent refractive sheet 12. The refractive sheet 12 is located between the light source 11 and the region 100 and is refracting one part of the light from the light source 11 into at least one illuminated segment, i.e. a halo, onto the region 100, and is reflecting another part of the light from the light source 11 so that this part of the light does not penetrate the refractive sheet 12.

The principle is illustrated in Fig. 3, where part of the light emitted from the light source 11 is reflected against the refractive sheet 12 and part of the light is refracted in a desired direction.

An advantage with this is that no separate collimation is needed to gather the light from the light source 11 into an illuminated segment.

In an embodiment according to Fig. 4, the light sources 11 are substantially point-like and arranged side-by- side in a single array covered by the refractive sheet 12. The refractive sheet 12 is refracting the light from all the light sources in the same way, thus creating one illuminated segment on the region 100.

In an embodiment according to Fig. 5, the light sources 11 are substantially point-like and arranged side-by- side in a single array covered by the refractive sheet 12. The refractive sheet 12 comprises two different areas 121, 122 with different optical properties.

Each area 121, 122, depending on the incident light angle from each of the light sources 11, is configured to refract a first part of the light emitted from each of the light sources 11 into at least one illuminated segment towards the region 100, while

simultaneously reflect a second part of the light emitted from each of the light sources 11 in a direction away from the region 100. The first area 121, when a first part of incident light from a light source 11a, 1 lb is refracted by the first area 121, is configured to reflect incident light from a neighboring light source 11a, 1 lb. Simultaneously, the second area 122, when a first part of incident light from a light source 1 la, 1 lb is refracted by the second area 122, is configured to reflect incident light from a neighboring light source 1 la, 1 lb. Thus, the first area 121 is refracting one part of the light from a first set of the light sources 1 la in one direction into a first illuminated segment on the region 100. A substantial part of the rest of the light from the first set of the light sources 1 la is reflected, thus never penetrating the refractive sheet 12. The second refractive area 122 is refracting one part of the light from a second set of the light sources 1 lb in one direction into a second illuminated segment on the region 100. A substantial part of the rest of the light from the first set of the light sources 1 lb is reflected, thus never penetrating the refractive sheet 12. The refractive sheet 12 may be common to said light sources 1 la, 1 lb. However, in an embodiment (not shown), separate refractive sheets 12 are provided for the light sources 11a and 1 lb, respectively.

A schematic overview of the refraction of light is seen in Fig. 6. In Fig. 6A, the principle with different refraction/reflection of two respective areas 121 and 122 are seen. In Fig. 6B, the first illuminated segment 61 on the region 100 and the second illuminated segment 62 on the region 100 are also shown.

In an embodiment, the first and second illuminated segments 61, 62 are essentially separated in a dimension perpendicular to the extension of the single array. Thus, the two illuminated segments 61, 62 are perceived as two separate halos of light.

In an embodiment, the first set of the light sources 1 la is of one color and the second set of light sources 1 lb is of another color. Thus, the first and second illuminated segments 61 and 62 may be of different colors.

In another embodiment, the first and second set of the light sources 11a, 1 lb are of the same color. Depending on the properties of the refractive sheet 12, influencing the respective refractions of the light, the two illuminated segments 61, 62 may be calibrated so as to be perceived either as two separate halos of light, or as the same halo.

In an embodiment, the color of the first and second set of the light sources 11a, 1 lb is independently variable so that the two illuminated segments 61, 62 are perceived as one halo of light when the light sources 1 la, 1 lb have the same color, and as two separate halos of light when the light sources 11a, 1 lb have different colors.

In an embodiment (not shown), the refractive sheet has three different refractive areas, thus causing the light from the light sources to be divided into three or more illuminated segments. Depending on the properties of the light sources, the three or more illuminated segments may be of same or different colors, and perceived as one or many halo(s), which will be appreciated by a person skilled in the art.

In an embodiment according to Fig. 7, the system 10 comprises a control unit 70, configured to individually control the light sources to form at least a first and a second group of light sources 11a, 1 lb. Each group of light sources 11a, 1 lb may consist of a single light source, such as a LED, but may also comprise several light sources, connected to the control unit so as to form a group of light sources.

In an embodiment, the illuminated segments 61, 62 are illuminated by different groups of light sources 11a, 1 lb.

As will be appreciated by a person skilled in the art, the number of light sources may depend on the available voltage in the system (e.g. 24V, 12V). The light sources may also be configured so that one illuminated segment 61, 62 may be illuminated by more than one group of light sources. As will be appreciated by a person skilled in the art, the light sources 11a, l ib may be any kind of light source. In an embodiment, the light sources 11 comprise Light Emitting Diodes (LEDs).

In an embodiment, the LEDs are of the same type.

In an embodiment, the LEDs are mounted on a printed circuit board (PCB). In an embodiment, the LEDs are mounted on the same PCB.

The LEDs may be both top emitting LEDs and side emitting LEDs, which will be appreciated by a person skilled in the art.

In an embodiment, an illumination system is provided, wherein the distance between the light sources 1 la, 1 lb and the refractive sheet 12 is variable. This allows adjustment of the region of illumination.

In an embodiment, the refractive sheet comprises a foil.

In an embodiment according to Fig. 8, the foil may be laminated onto a carrier 80. The first area 121 is laminated onto one of two opposite sides of the carrier 80 and second area 122 is laminated onto the other of the two opposite sides of the carrier 80.

In an embodiment (not shown), the first and second area 121, 122 are laminate don the same side of the carrier 80.

In an embodiment according to Fig. 9, a display device 90 having ambient light capability is provided, wherein the ambient light capability is provided by an

illumination system according some embodiments.

The display device may be any kind of display device, such as selected from the group consisting of computer monitor display, cathode ray tube (CRT) display, liquid crystal display (LCD), light emitting diode (LED) display, organic light emitting diode (OLED) display, plasma discharge display, or a display using a functionally equivalent display technology.

It should be appreciated that the illumination system according to some embodiments is not limited merely to display devices, but may be utilized in any illumination system, for any device, for which segmented illumination is desired. Hence the illumination system according to some embodiments could be utilized in e.g. a hifi system, on a receiver, a telephone, in conjunction with a noticeboard, wall etc. Although the present invention has been described above with reference to specific embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the

accompanying claims and, other embodiments than the specific above are equally possible within the scope of these appended claims. The invention may be implemented in any suitable form including hardware, software, firmware or any combination of these. The elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the invention may be implemented in a single unit, or may be physically and functionally distributed between different units and processors.

In the claims, the term "comprises/comprising" does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor.

Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. The terms "a", "an", "first", "second" etc do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.

Claims

CLAIMS:

1. An illumination system (10) for segmented illumination of a region (100), comprising:

at least a first light source (11a) and a second light source (1 lb) arranged side- by-side in a single array; and

- a semi-transparent refractive sheet (12) positioned between the light sources

(11) and the region (100);

wherein the semi-transparent refractive sheet is composed of at least a first area (121) and second area (122), wherein each area (121, 122), depending on the incident light angle from each of the light sources (11), is configured to:

- refract a first part of the light emitted from each of the light sources (11) into at least one illuminated segment (61, 62) towards the region (100), and

reflect a second part of the light emitted from each of the light sources (11) in a direction away from the region (100), wherein

the first area (121), when a first part of incident light from a light source (11a, 1 lb) is refracted by the first area (121), is configured to reflect incident light from a neighboring light source (11a, 1 lb), and

the second area (122), when a first part of incident light from a light source (11a, 1 lb) is refracted by the second area (122), is configured to reflect incident light from a neighboring light source (11a, l ib).

2. An illumination system according to claim 1, wherein the refractive sheet (12) is common to said light sources (11).

3. An illumination system according to claim 1 or 2, further comprising:

a control unit (70) configured to individually control the light sources (11) to form at least a first and a second group of light sources (11a, l ib).

4. An illumination system according to claim 1 or 2, wherein each area (121,

122), depending on the incident light angle from each of the light sources (11a, 1 lb), is configured to:

refract a first part of the light emitted from each of the light sources (11a, l ib) into a first illuminated segment (61) towards the region (100), and

refract a second part of the light emitted from each of the light sources (11a, 1 lb) into a second illuminated segment (61) towards the region (100).

5. An illumination system according to claim 4, wherein the first and second illuminated segments (61, 62) are essentially separated in a dimension perpendicular to the extension of the single array.

6. An illumination system according to claim 4 or 5, wherein the illuminated segments (61, 62) are illuminated by different groups of light sources (1 la, 1 lb).

7. An illumination system according to claim 1 or 2, wherein the refractive sheet (12) comprises a foil.

8. An illumination system according to claim 7, wherein the foil is laminated onto a carrier (80).

9. An illumination system according to claim 8, wherein the first area (121) is laminated onto one of two opposite sides of the carrier (80) and second area (122) is laminated onto the other of the two opposite sides of the carrier (80).

10. An illumination system according to claim 1, wherein the light sources (11a, l ib) comprises Light Emitting Diodes (LEDs).

11. An illumination system according to claim 10, wherein the LEDs are of the same type.

12. An illumination system according to claim 10 or 11, wherein the LEDs are mounted on the same printed circuit board (PCB).

13. An illumination system according to claim 1, wherein the distance between the light sources (11a, 1 lb) and the refractive sheet (12) is variable, to allow adjustment of the region of illumination.

14. A display device (90) having ambient light capability, wherein the ambient light capability is provided by an illumination system according to claim 1.

15. A display device (90) according to claim 14, wherein the display device is selected from the group consisting of:

computer monitor display;

cathode ray tube (CRT) display;

liquid crystal display (LCD);

light emitting diode (LED) display;

organic light emitting diode (OLED) display;

plasma discharge display;

or a display using a functionally equivalent display technology.