GB2541941A - Diffuser - Google Patents

Abstract

A diffuser 101 for use with a plurality of light emitting diodes in a luminaire comprises a plurality of diffuser cells 102. Each diffuser cell 102 comprises a cell wall 103 extending in a depth direction D and defining a cell interior with upper and lower openings. The diffuser cell 102 provides an unobstructed light path through the cell interior for a respective LED 501 aligned with the upper opening of the diffuser cell. The diffuser has means for inhibiting contact through each cell interior with a respective LED 501. Thus each diffuser cell 102 may have a safety barrier arrangement 201, 202 and/or be dimensioned to provide a cross-sectional area between each cell wall that is sufficiently narrow to inhibit contact with the aligned LED 501.

Description

DIFFUSER

Field of the Invention

The present invention relates to a diffuser, in particular to a grid diffuser for an array of light emitting diodes (LEDs).

Background of the Invention

Light emitting diode (LED) lighting apparatus comprising a printed circuit board supporting an array of LEDs is known. LED lights are often favoured for exhibiting improved operational efficiency and lifetime when compared to incandescent or fluorescent lamps. LEDs are point light sources and can present optical challenges to achieving a desired lighting effect. For example, a designer may aspire to control such aspects as glare, beam angle and homogeneity of output light. Optical diffusers function to spread or diffuse light from a light source, and can be used to more evenly distribute light across an area (minimising or removing high intensity bright spots), to soften light, and to shape light.

Customarily, lighting apparatus printed circuit boards have been operated using an electricity supply having a voltage equal to or less than 50V AC rms. It is however increasingly found that lighting apparatus printed circuit boards are being operated using an electricity supply having a voltage greater than 50V AC rms. This higher voltage represents a greater electrical hazard and a greater risk to life if a person comes into contact with electrically live componentry.

Summary of the Invention

According to a first aspect there is provided a diffuser for use with a plurality of light emitting diodes (LEDs), said diffuser comprising a plurality of diffuser cells, each diffuser cell comprising cell walling extending in a depth direction of said diffuser and defining a cell interior with upper and lower openings, said diffuser cell providing an unobstructed light path through the cell interior for a respective LED aligned with the upper opening of the diffuser cell, and said diffuser comprising means for inhibiting contact made through the cell interior of each diffuser cell with a respective LED aligned with the upper opening of the respective diffuser cell.

In an embodiment, each diffuser cell further comprises a safety barrier arrangement for inhibiting contact made through the cell interior of each diffuser cell with a respective LED aligned with the upper opening of the respective diffuser cell.

The safety barrier arrangement may comprise at least one bar extending across the cell interior of the diffuser cell. The or each bar may extend across the upper opening of the cell interior. The safety barrier arrangement may comprise parallel spaced bars. The width W of the or each gap G provided by the safety barrier arrangement may be sufficiently narrow to satisfy British Standard BS EN 61032:1998 / International Electrotechnical Commission Standard IEC 61032:1997 - Test Finger Probe (Articulated). The diffuser may comprise first and second layers spaced in the depth direction of the diffuser, one of the first and second layers comprising the diffuser cells and the other of the first and second layers providing the safety barrier arrangements of the diffuser cells.

In an embodiment, each diffuser cell is dimensioned to provide a cross-sectional area between the cell walling that is sufficiently narrow to satisfy British Standard BS EN 61032:1998 / International Electrotechnical Commission Standard IEC 61032:1997 -Test Finger Probe (Articulated)

The diffuser may comprise an array of diffuser cells, the array comprising rows and columns of diffuser cells. The diffuser cells may have a hexagonal shape. The diffuser may comprise a series of diffuser cells along one of the row direction and the column direction that are arranged corner to corner, and a series of diffuser cells along the other of the row direction and the column direction that are arranged face to face.

The diffuser may have a rectangle or a square shape.

The cell walling of the diffuser cells may be translucent.

The diffuser may comprise a securing arrangement for securing the diffuser to a printed circuit board (PCB) supporting the array of LEDs. The securing arrangement may comprise one or more clips.

The diffuser may be rigid.

The diffuser may be fabricated from a plastics material. The manufacture of the diffuser may involve a moulding process.

According to a second aspect there is provided a diffuser according to the first aspect in combination with a luminaire.

According to a third aspect there is provided a luminaire comprising a diffuser according to the first aspect, the luminaire comprising a plurality of light emitting diodes (LEDs), the diffuser comprising a corresponding plurality of diffuser cells, and the plurality of LEDs and the plurality of diffuser cells so aligned such that a respective single LED is aligned with a respective single diffuser cell.

The luminaire may be configured to allow a beam angle of up to and including 120 degrees.

Different aspects and embodiments of the invention may be used separately or together.

Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with the features of the independent claims as appropriate, and in combination other than those explicitly set out in the claims.

Brief Description of the Drawings

The present invention will now be more particularly described, with reference to the accompanying drawing, in which:

Figure I shows a diffuser comprising a plurality of diffuser cells, according to a specific embodiment;

Figure 2 shows features of the diffuser cells of the diffuser of Figure I in further detail;

Figure 3 shows features of the array of diffuser cells the diffuser of Figures I & 2;

Figure 4 shows the diffuser of Figures 1-3 in a luminaire comprising an array of LEDs;

Figure 5 shows a plan view of the array of diffuser cells of the diffuser of Figures I -4 and the array of LEDs of the luminaire of Figure 4 relatively aligned;

Figure 6 shows a perspective view of the diffuser of Figure I; and Figure 7 shows an alternative perspective view of the diffuser of Figure I.

Description

Example embodiments are described below in sufficient detail to enable those of ordinary skill in the art to embody and implement the systems and processes herein described. It is important to understand that embodiments can be provided in many alternate forms and should not be construed as limited to the examples set forth herein.

With regard to the use of the relative terms such as “upper” and “lower” throughout this specification, these relate to the orientation of the diffuser, diffuser cells, diffuser cell structure and luminaire shown in the Figures as illustrative embodiments of the invention and are not to be interpreted in any way to limit the invention unless stated.

According to the present invention, a diffuser for use with a plurality of LEDs and incorporating electrical hazard protection is provided. A diffuser 101 according to a specific embodiment is shown in Figure I. The diffuser 101 is suitable for use with a plurality of LEDs (not shown in this Figure).

Diffuser 101 comprises a plurality of diffuser cells, such as diffuser cell 102. Each diffuser cell 102 comprises cell walling 103 that extends in a depth direction D of the diffuser 101 and that defines a cell interior with upper and lower openings. The depth direction D is indicated in Figure I as the direction extending from the upper side 104 to the lower side 105 of the diffuser 101.

As will be described in further detail, each diffuser cell 102 provides an unobstructed light path through the cell interior for an LED aligned with the upper opening of the diffuser cell 102. As will also be described in further detail, the diffuser 101 comprises means for inhibiting contact made through the cell interior with a respective LED aligned with the upper opening of the diffuser cell 102.

Each diffuser cell may be dimensioned to inhibit contact made through the cell interior with a respective LED aligned with the upper opening of the diffuser cell. Alternatively, or additionally, each diffuser cell may comprise a safety barrier arrangement for inhibiting contact made through the cell interior with a respective LED aligned with the upper opening of the diffuser cell.

According to the specific embodiment shown in Figure I, and as will be described in further detail, each diffuser cell 102 of diffuser 101 comprises a safety barrier arrangement 106 for inhibiting contact made through the cell interior with a respective LED aligned with the upper opening of the diffuser cell 102.

Features of the diffuser cells of the diffuser 101 of Figure I are shown in further detail in Figure 2.

In an embodiment, the safety barrier arrangement of the diffuser cell comprises at least one bar that extends across the cell interior of the diffuser cell. In an example, the, or each, bar of the safety barrier arrangement extends across the upper opening of the cell interior of the diffuser cell.

In this illustrated embodiment, the safety barrier arrangement 106 comprises parallel spaced bars, such as safety bars 201 and 202, arranged across the cell interior of the diffuser cell 102. The width W of the or each gap G provided by the safety barrier arrangement 106 is sufficiently narrow to satisfy British Standard BS EN 61032:1998 / International Electrotechnical Commission Standard IEC 61032:1997 - Test Finger Probe (Articulated). A gap G provided by the safety barrier arrangement may be provided between a bar of the safety barrier arrangement and cell walling of the diffuser cell, or may be provided between neighbouring bars of the safety barrier arrangement. In this illustrated embodiment, apertures A are present between neighbouring diffuser cells 102 of the diffuser 101, and the width of the apertures A, whether or not provided with a safety barrier arrangement, are also sufficiently narrow to satisfy British Standard BS EN 61032:1998 / International Electrotechnical Commission Standard IEC 61032:1997 - Test Finger Probe (Articulated).

The cell walling 103 of the diffuser cells 102 of the diffuser 101 may have any desired translucency or opacity. In the present specific embodiment, the cell walling 103 is translucent.

In this embodiment, the diffuser 101 takes the form of a planar grid. According to the present embodiment, the diffuser 101 is rigid.

In this embodiment, the diffuser 101 is fabricated from a plastics material. According to the present embodiment, the manufacture of the diffuser 101 involves a moulding process.

Features of the plurality of diffuser cells 102 of diffuser 101 will now be described with reference to Figure 3.

In this illustrated specific embodiment, the diffuser 101 comprises an array of diffuser cells 102, the array comprising rows, extending in a row direction R, and columns, extending in a column direction C, of diffuser cells 102. The row direction R and column direction C extend substantially perpendicularly to each other. In the present embodiment, the diffuser cells 102 have a hexagonal shape, in this illustrated example a regular hexagonal shape.

According to this embodiment, the series of diffuser cells 102 along one of the row direction R and column direction C are arranged corner to corner and the series of diffuser cells 102 along the other of the row direction R and column direction C are arranged face to face. As can be seen in this Figure at least, in this illustrated example, the series of diffuser cells 102 along the row direction R are arranged corner to corner, such as indicated at 301, 302, 303 and 304, and the series of diffuser cells 102 along the column direction C are arranged face to face, such as indicated at 305, 306, 307 and 308.

In this embodiment, the diffuser 101 has a square shape, and the diffuser cells are arranged in a 2-dimensional array. In an alternative embodiment, the diffuser has a rectangular shape. The diffuser cells may then be arranged in a linear or 2-dimensional array.

The diffuser 101 of the present embodiment is configured for use with a printed circuit board (not shown in this Figure) on which an array of LEDs (not shown in this Figure) is supported. In this illustrated embodiment, the diffuser 101 comprises a securing arrangement 309 for securing the diffuser 101 to a printed circuit board (PCB) supporting an array of LEDs. The securing arrangement 309 may comprise at least one clip 310. In this illustrated example, the securing arrangement 309 comprises at plurality of clips 3 10 for clipping onto a lighting apparatus printed circuit board (PCB) (not visible in this Figure) with supported LEDs.

Diffuser ΙΟΙ is shown in Figure 4 in a luminaire 401. The luminaire 401 comprises a printed circuit board (PCB) (not visible in this Figure) that supports a plurality of LEDs (not visible in this Figure).

The luminaire 401 comprises an array of LEDs (not visible in this Figure) and the diffuser 101 comprises a corresponding array of diffuser cells 102. The diffuser 101 is oriented such that the LEDs of the luminaire 401 are over the upper side of the diffuser 101 and the lower side 105 of the diffuser 101 is presented towards a viewer.

Figure 5 shows a plan view of the diffuser 101 positioned for use with the array of LEDs of luminaire 401.

In the illustrated arrangement, the plurality of LEDs 501 of the luminaire 401 and the diffuser 101 are relatively aligned such that a respective single LED 501 is aligned with a respective single diffuser cell 102. As shown, one diffuser cell 102 is provided for each LED 501, and, in plan view, the cell walling 103 of each diffuser cell 102 surrounds one LED 501, which is aligned with the upper opening of the diffuser cell 102.

Each diffuser cell 102 provides an unobstructed light path through the cell interior for a respective LED aligned with the upper opening of the diffuser cell 102. By ‘unobstructed’ it is meant that there is a virtual line or column extending through the diffuser cell along which there is no physical obstruction. Thus, light emitted from an aligned LED can travel through the respective diffuser cell along the unobstructed light path unaffected.

As stated previously, each diffuser cell 102 is arranged to inhibit contact made through the cell interior with a respective LED aligned with the upper opening of the diffuser cell 102.

According to this illustrated embodiment, each diffuser cell 102 comprises a safety barrier arrangement for inhibiting contact made through the cell interior with the respective LED aligned with the upper opening of the diffuser cell. The safety barrier arrangement provides protection against the electrical hazard posed by the LED and supporting element. In particular, the safety barrier arrangement functions to prevent a human finger from being inserted through the diffuser cell into contact with electrically live componentry. When the diffuser is located for use, the safety barrier arrangement inhibits contact being made through the diffuser cell, from the lower side to electrically live componentry by the upper side. This is particularly beneficial in applications in which LED lighting apparatus printed circuit boards are being operated using an electricity supply having a voltage greater than 50V AC rms.

The safety bars 201 and 202 of the safety barrier arrangement of diffuser 101 can be seen in this Figure.

In an embodiment, luminaire 401 with diffuser 101 is configured to allow a beam angle of up to and including 120 degrees.

Figure 6 shows a perspective view looking up towards the lower side 105 of diffuser 101 in use with luminaire 401.

As discussed previously, each diffuser cell 102 provides an unobstructed light path, indicated in this Figure by arrow LP, through the cell interior for a respective LED aligned with the upper opening of the respective diffuser cell 102. Emitted light from the LED travelling along the unobstructed light path passes through the diffuser cell 102 unchanged. Emitted light incident with the cell walling 103 of the diffuser 102 is however altered. Thus, if the light emitted along the unobstructed light path LP is perceived as travelling in an axial direction through the cell interior, light emitted in a radial direction relative to that axial direction is diffused by the cell walling 103. With a one-to-one ratio of LEDs and diffuser cells, the light emitted by each LED is controlled by the respective diffuser cell for that LED.

It can be seen in this Figure that the safety bars 201 and 202 of the safety barrier arrangement of diffuser 101 extend over the upper openings of the diffuser cells 102. In this illustrated embodiment, and as shown, the structure of the diffuser 101 is such that the diffuser 101 comprises first and second layers 601, 602 that are spaced in the depth direction of the diffuser 101, one of the first and second layers 601, 602 comprising the diffuser cells 102 and the other of the first and second layers 601, 602 providing the safety barrier arrangement 106 of the diffuser cells 102. In the illustrated example, the upper, first layer 601 provides the safety barrier arrangement with bars, such as safety bars 201 and 202, and the second, lower layer 602 provides diffuser cells 102. Thus, with the shown arrangement, the diffuser structure may be perceived as having a mesh-like layer with intersecting bars from which diffuser cells extend downwardly. In an embodiment, the depth of the first, upper layer 601 is approximately 2 mm and the depth of the second, lower layer 602 is approximately 6 mm. It is to be appreciated however, in an alternative embodiment, the diffuser may have a structure that does not comprise such distinct layers. In such an embodiment, safety bars of the safety barrier arrangement may extend across, but not over, the upper openings of the diffuser cells.

In the shown arrangement of Figure 6, the positioning of the bars of the safety barrier arrangement towards the upper openings of the diffuser cells 102 of diffuser 101 places the bars close to the light source so that any interference with emitted light by the bars is minimised. This is advantageous in reducing any disruption in the functioning of the diffuser 101 caused by the presence of the safety barrier arrangement.

With the illustrated safety barrier arrangement, insertion of a standard test finger probe through the upper opening of the diffuser cell is prevented.

In an example, the safety barrier arrangement is arranged to prevent insertion of a standard test finger probe through the lower opening of the diffuser cell, in turn preventing insertion of the standard test finger probe through the upper opening. In an alternative example, the safety barrier arrangement is arranged to prevent insertion of a standard test finger probe through both the lower and upper openings of the diffuser cell. In a further alternative example, the safety barrier arrangement is arranged to prevent insertion of a standard test finger probe beyond a point between the lower and upper openings of the diffuser cell. It is thus to be appreciated that in an embodiment in which the diffuser is provided with a safety barrier arrangement, the safety barrier arrangement may prevent insertion of a standard test finger probe beyond a single point or a plurality point through the depth of the cell interior of the diffuser cell.

It is to be appreciated that although only a single example of a safety barrier arrangement is described herein and is shown in the Figures, other examples of safety barrier arrangements may be utilised that provide the same functionality.

In an alternative embodiment of a diffuser (not illustrated in the accompanying Figures), each diffuser cell is dimensioned to provide a cross-sectional area between the cell walling that is sufficiently narrow to satisfy British Standard BS EN 61032:1998 / International Electrotechnical Commission Standard IEC 61032:1997 - Test Finger Probe (Articulated) and, in this way, to inhibit contact made through the cell interior with a respective LED aligned with the upper opening of the diffuser cell. The diffuser cells of the diffuser of this embodiment may have any suitable shape and size so long as the dimensions of each diffuser cell are sufficiently narrow to prevent insertion of a standard test finger probe through the upper opening of the diffuser cell. As indicated previously, insertion of the standard test finger probe through the upper opening of the diffuser cell may be prevented at the location of the upper opening of the diffuser cell, at the location of the lower opening of the diffuser cell, at a location between the lower and upper openings of the diffuser cell or at multiple locations through the depth of the diffuser cell. In an example, at least the lower opening of the diffuser cell has a substantially elongate rectangular shape, with at least the width dimension being sufficiently narrow to prevent insertion of a standard test finger probe therethrough.

In a further alternative embodiment of a diffuser (not illustrated in the accompanying Figures), the cell walling of each diffuser cell is dimensioned to satisfy British Standard BS EN 61032:1998 / International Electrotechnical Commission Standard IEC 61032:1997 - Test Finger Probe (Articulated) and each diffuser cell is also provided with a safety barrier arrangement.

Hence, a diffuser comprising means for inhibiting contact made through the cell interior with a respective LED aligned with the upper opening of the diffuser cell may comprise diffuser cells that are dimensioned to inhibit contact made through the cell interior, diffuser cells that comprise a safety barrier arrangement for inhibiting contact made through the cell interior, or diffuser cells that are dimensioned to inhibit contact made through the cell interior and that comprise a safety barrier arrangement for inhibiting contact made through the cell interior.

Thus, a diffuser cell structure comprising cell walling defining a cell interior with upper and lower openings, the diffuser cell structure providing an unobstructed light path through the cell interior, and the diffuser cell structure dimensioned to inhibit passage of a standard test finger probe through at least one of the upper and lower openings of the cell interior and/or comprising a safety barrier arrangement for inhibiting passage of a standard test finger probe through at least one of the upper and lower openings of the cell interior is provided. A diffuser for use with a plurality of light emitting diodes (LEDs), the diffuser comprising a plurality of diffuser cells, each diffuser cell comprising the diffuser cell structure, is also provided.

The diffuser in combination with a luminaire is further provided. A luminaire comprising the diffuser, the luminaire comprising a plurality of light emitting diodes (LEDs) and the plurality of LEDs and the diffuser cells of the diffuser are so aligned such that a respective single LED is aligned with a respective single diffuser cell is yet further provided.

It is to be appreciated that variations in a diffuser, a diffuser cell structure, a diffuser in combination with a luminaire and a luminaire comprising a diffuser from that described and/or illustrated herein are envisaged that would still be in accordance with the present invention.

The diffuser may have any suitable dimensions, and may comprise any suitable number of diffuser cells. The diffuser may comprise a one-dimensional linear array of diffuser cells or a two-dimensional array of diffuser cells. The diffuser may have any suitable shape, any suitable upper side profile and any suitable lower side profile. The diffuser cells may have any suitable shape and dimensions, and may be arranged in any suitable arrangement. The safety barrier arrangement may have any suitable alternative construction to that described above and as shown in the accompanying Figures may be utilised. The relative dimensions between any layers of the diffuser or diffuser cell structure may vary. The diffuser and/or diffuser cells may be fabricated from any suitable material or combination of materials, and may be manufactured using any suitable technique, method or process or combination of techniques, methods or processes. The diffuser and/or diffuser cells may have any desired degree of transparency or opacity, colouration and/or surface finish. In an embodiment, the diffuser cell walling is opaque. The degree of rigidity or flexibility of the diffuser may vary between embodiments. The diffuser may be used in or in combination with any suitable type of luminaire. It is to be appreciated that 3-dimensional variations may also be in accordance with the present invention. A plurality of diffuser cells may include diffuser cells that are uniform in all aspects or may include one or more diffuser cells that vary in one of more aspects from one or more other diffuser cells.

The present invention provides a diffuser that is lightweight, cost-effective and that includes human protection against dangerous contact with hazardous live electrical componentry.

Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiments shown and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.

Claims (25)

Claims

1. A diffuser for use with a plurality of light emitting diodes (LEDs), said diffuser comprising a plurality of diffuser cells, each diffuser cell comprising cell walling extending in a depth direction of said diffuser and defining a cell interior with upper and lower openings, said diffuser cell providing an unobstructed light path through the cell interior for a respective LED aligned with the upper opening of the diffuser cell, and said diffuser comprising means for inhibiting contact made through the cell interior of each diffuser cell with a respective LED aligned with the upper opening of the respective diffuser cell.

2. A diffuser as claimed in claim I, wherein each diffuser cell further comprising a safety barrier arrangement for inhibiting contact made through the cell interior of each diffuser cell with a respective LED aligned with the upper opening of the respective diffuser cell.

3. A diffuser as claimed in claim 2, wherein said safety barrier arrangement comprises at least one bar extending across the cell interior of the diffuser cell.

4. A diffuser as claimed in claim 3, wherein the or each bar extends across said upper opening.

5. A diffuser as claimed in claim 3 or claim 4, wherein said safety barrier arrangement comprises parallel spaced bars.

6. A diffuser as claimed in any of claims 2 to 5, wherein the width W of the or each gap G provided by the safety barrier arrangement is sufficiently narrow to satisfy British Standard BS EN 61032:1998 / International Electrotechnical Commission Standard IEC 61032:1997 - Test Finger Probe (Articulated).

7. A diffuser as claimed in any of claims 2 to 6, comprising first and second layers spaced in the depth direction of said diffuser, one of said first and second layers comprising the diffuser cells and the other of said first and second layers providing the safety barrier arrangements of the diffuser cells.

8. A diffuser as claimed in claim I, wherein each said diffuser cell is dimensioned to provide a cross-sectional area between the cell walling that is sufficiently narrow to satisfy British Standard BS EN 61032:1998 / International Electrotechnical Commission Standard IEC 61032:1997 - Test Finger Probe (Articulated)

9. A diffuser as claimed in any preceding claim, comprising an array of diffuser cells, the array comprising rows and columns of diffuser cells.

10. A diffuser as claimed in any preceding claim, wherein each diffuser cell has a hexagonal shape.

11. A diffuser as claimed in claims 8 and 9, wherein, the series of diffuser cells along one of the row direction and the column direction are arranged corner to corner, and the series of diffuser cells along the other of the row direction and the column direction are arranged face to face.

I 2. A diffuser as claimed in any of preceding claim, wherein the shape of said diffuser is one of: a rectangle, a square.

13. A diffuser as claimed in any preceding claim, wherein said cell walling is translucent.

14. A diffuser as claimed in any preceding claim, comprising a securing arrangement for securing the diffuser to a printed circuit board (PCB) supporting said array of LEDs.

15. A diffuser as claimed in claim 14, wherein said securing arrangement comprising one or more clips.

16. A diffuser as claimed in any preceding claim, wherein said diffuser is rigid.

I 7. A diffuser as claimed in any preceding claim, fabricated from a plastics material.

18. A diffuser as claimed in claim 17, wherein the manufacture of the diffuser involves a moulding process.

19. A diffuser as claimed in any preceding claim, in combination with a luminaire.

20. A luminaire comprising a diffuser, the diffuser as claimed in any preceding claim, said luminaire comprising a plurality of light emitting diodes (LEDs), said diffuser comprising a corresponding plurality of diffuser cells, and said plurality of LEDs and said plurality of diffuser cells so aligned such that a respective single LED is aligned with a respective single diffuser cell.

21. A luminaire as claimed in claim 20, configured to allow a beam angle of up to and including 120 degrees.

22. A diffuser, substantially as described herein with reference to the accompanying drawings.

23. A diffuser in combination with a luminaire, substantially as described herein with reference to the accompanying drawings.

24. A luminaire comprising a diffuser, substantially as described herein with reference to the accompanying drawings.

25. A diffuser cell structure for use in a diffuser, substantially as described herein with reference to the accompanying drawings.