GB2540378A - Illuminated displays - Google Patents

Illuminated displays Download PDF

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Publication number
GB2540378A
GB2540378A GB1512310.2A GB201512310A GB2540378A GB 2540378 A GB2540378 A GB 2540378A GB 201512310 A GB201512310 A GB 201512310A GB 2540378 A GB2540378 A GB 2540378A
Authority
GB
United Kingdom
Prior art keywords
light
illumination module
guide panel
light guide
transmissive material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB1512310.2A
Other versions
GB201512310D0 (en
Inventor
David Shadbolt Philip
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZETA SPECIALIST LIGHTING Ltd
Original Assignee
ZETA SPECIALIST LIGHTING Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ZETA SPECIALIST LIGHTING Ltd filed Critical ZETA SPECIALIST LIGHTING Ltd
Priority to GB1512310.2A priority Critical patent/GB2540378A/en
Publication of GB201512310D0 publication Critical patent/GB201512310D0/en
Publication of GB2540378A publication Critical patent/GB2540378A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F13/00—Illuminated signs; Luminous advertising
    • G09F13/18—Edge-illuminated signs
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/003—Lens or lenticular sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0066—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form characterised by the light source being coupled to the light guide
    • G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
    • G02B6/0083—Details of electrical connections of light sources to drivers, circuit boards, or the like
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
    • G02B6/0085—Means for removing heat created by the light source from the package
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F13/00—Illuminated signs; Luminous advertising
    • G09F13/04—Signs, boards or panels, illuminated from behind the insignia
    • G09F13/0418—Constructional details
    • G09F13/049—Edge illuminated signs, boards or panels
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F13/00—Illuminated signs; Luminous advertising
    • G09F13/20—Illuminated signs; Luminous advertising with luminescent surfaces or parts
    • G09F13/22—Illuminated signs; Luminous advertising with luminescent surfaces or parts electroluminescent
    • G09F2013/222—Illuminated signs; Luminous advertising with luminescent surfaces or parts electroluminescent with LEDs

Abstract

An illumination module for a display apparatus comprises a light guide panel 1 and at least one light generating module 2 arranged at an edge of the light guide panel. The light generating module comprises a plurality of light emitting diodes 12 embedded in a light transmissive material 16. An outer surface of the light transmissive material 16 has one or more portions which are curved so as to redirect light from said LEDs 12 into the light guide panel. The outer surface of the light transmissive material is preferably in contact with an edge 1a of the light guide panel, the edge 1a of the light guide panel being complementarily curved. The surface of the light guide panel is preferably etched to promote light dispersion. The light transmissive material preferably acts to provide an offset in correlated colour temperature to the light emitted by the LEDs.

Description

Illuminated Displays
This invention relates primarily, although not exclusively, to illumination of displays such as information boards, advertising stands, traffic signs and the like.
Illuminated displays are a common feature of many public spaces. Many different technologies are available for these and active display screens such as those based on light emitting diode (LED) pixels or plasma screens are becoming increasingly popular. However these remain relatively expensive and there is still large demand for illuminated displays giving static information or images. This could be a permanent panel in the case of a traffic sign for example or could include a replaceable poster as in the case of an advertising display for example. In both cases illumination is provided from behind and passes through the printed graphic panel. Commonly illumination is provided by fluorescent tubes which do not provide very even illumination and have relatively short operating life, particularly if they are regularly switched on and off.
It is an object of the present invention to improve such displays.
When viewed from a first aspect the invention provides a display apparatus comprising at least one translucent display surface, and an illumination module arranged to illuminate said translucent display surface, said illumination module comprising a light guide panel and at least one light generating module arranged at an edge of said light guide panel, said light generating module comprising a plurality of light emitting diodes fully embedded in a light transmissive material, an outer surface of said light transmissive material having one or more portions which is/are curved so as to redirect light from said LEDs.
When viewed from a second aspect the invention provides an illumination module for a display apparatus, said illumination module comprising a light guide panel and at least one light generating module arranged at an edge of said light guide panel, said light generating module comprising a plurality of light emitting diodes fully embedded in a light transmissive material, an outer surface of said light transmissive material having one or more portions which is/are curved so as to redirect light from said LEDs.
Thus it will be seen by those skilled in the art that in accordance with the invention a display apparatus of the kind described has an illumination module, the light generating module of which has LEDs embedded in a potting material which is shaped to provide a redirection or lensing effect. This provides protection for the LEDs against damage and moisture ingress whilst at the same time providing focussing or other redirection of light emanating from them. This may give more robust, cost effective arrangement compared to known arrangements. It may also improve light transmission by reducing the number of transitions across optical boundaries that the light must make as a result of eliminating an air gap.
In a set of embodiments the outer surface of the light transmissive material is in physical contact with an edge of the light guide panel. This further improves light transfer efficiency by minimising air gaps. Preferably the edge of the light guide panel has a complementary curved portion to allow a close fit to the light transmissive material.
In a set of embodiments the light generating module comprises a releasable connector for making electrical connection to the rest of said display apparatus.
This permits fast and reliable installation and replacement of the module.
Preferably the connector is a waterproof one.
In a set of embodiments the light generating module comprises constant current drivers for the LEDs. This allows a simple electrical supply to be provided to it and also enables the option of addressable dimming.
It will be appreciated that the size, number and location of the light generating module(s) can be chosen to give a desired light distribution on the light guide panel. Similarly the lens effect provided by the outer surface(s) of the light transmissive material can be used to provide a desired light pattern. This could be uniform illumination or could provide enhanced illumination in a predetermined region, e.g. to highlight or draw attention to a specific part of the corresponding display surface. This can also be done in combination with the power controllers for the LEDs, such as constant current drivers provided in the light generating module, by setting their output at different power levels.
The light guide panel will typically be made from a material through which light can pass and which also acts at least somewhat to diffuse or scatter light passing through it. This could be uniform - as for example with a frosted or other whitened surface, or could be only at particular parts of as the result of a surface microtexture. In a set of such embodiments a surface of the light guide panel is etched with a plurality of lines to promote light dispersion therefrom. In a set of such embodiments said lines are parallel but non-uniformly spaced. In other embodiments they are arranged in a non-linear pattern. In a set of embodiments the light guide panel is made of acrylic.
The outer surface of the light transmissive material could be concave, convex or a mixture of the two. There may be individual curved portions corresponding to the respective individual LEDs or a plurality - which could be a subset or all of the LEDs in the illumination module - may be associated with a single curved region.
In a set of embodiments the illumination module comprises a carrier providing the LEDs and light transmissive material and a heat sink in good thermal contact with the carrier. In other embodiments the heatsink could be provided as part of a housing of the display apparatus. The heatsink may be formed of a material having good thermal conductivity such as metal. It may be formed with features such as ribs, fins or the like so as to have an enhanced surface area. Further cooling means such as one or more fans could also be provided.
In a set of embodiments the light transmissive material acts to provide an offset in correlated colour temperature (CCT) to the light emitted by the LEDs. The CCT of the LEDs can thus be chosen accordingly to give the desired CCT taking this into account. The LEDs may all be the same colour, e.g. white, or different colours.
Certain embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
Fig. 1 is a front view of the illumination module for a display apparatus in accordance with the invention;
Fig. 2 is a close-up sectional view of the light generating module of Fig 1;
Fig. 3 is an illustration of the pattern of etched lines on the acrylic light guide panel depicted in Fig. 1;
Fig. 4 is a front view of an alternative apparatus in accordance with the invention;
Fig. 5 is a close-up sectional view of an alternative light generating module which may be used with either of the previous embodiments.
Fig. 1 shows an illumination module for a display case in accordance with the invention, the outing housing and printed graphic panel of which has been removed. This could, for example, be used as an advertising display in a public space. The illumination module comprises an essentially rectangular acrylic light guide panel 1. As will be described in greater detail below the reference to Fig. 3, the acrylic panel 1 is etched on its rear surface which causes it to scatter light passing through it in a planar direction out of the front of the panel.
Along each of the long edges of the light guide panel 1 is a light generating module 2 which is described in more detail below. The acrylic panel 1 is supported on a pair of support bosses 3 and is also fixed to the light generating module 2 by dowel pins (not shown) on each side. Four frame discs 4 are used to mount the illumination module shown in Fig. 1 in use to the main body of a poster case unit. A power supply unit 5 is provided to power the light generating modules 2 via a wiring loom 6. Detachable waterproof connectors 6a allow easy connection and disconnection of the light generating modules 2 from the wiring loom 6.
Fig. 2 shows a cross-sectional view of the light generating module 2. This comprises an extruded aluminium frame member 8 which defines a channel 10 for receiving the edge of the acrylic light guide panel 1.
Below the acrylic panel 1 at the bottom of the channel 10 is an LED carrier assembly which includes a linear array or strip of LEDs 12 and their associated constant current driver printed circuit boards (not shown) mounted using thermal adhesive tape in a metal carrier 14 which has a U-shaped cross-section and predrilled mounting holes to secure it to the frame. The carrier 14 is filled with a transparent resin potting material 16, for example an optically clear grade of room temperature vulcanisation silicone such that the LEDs 12 are embedded in it. The outer surface of the resin material 16 has a concave curved form to match the convex shape of the periphery 1a of the acrylic panel so that they mate closely with one another.
The frame member 8 acts as an effective heat sink for the LED carrier 14. It defines two parallel flange pairs 18 which act as heat sink fins, although they could also be used for clipping to other structures in other applications.
The rear (inwardly facing) surface 1b of the acrylic light guide panel 1 is laser etched with a series of parallel but non-uniformly spaced lines 20 as can be seen in Fig. 3. These extend parallel to the long edges of the light guide panel 1 so that the light emanating from the light generating modules 2 which travels in the generally transverse direction is incident on the etched lines 20 approximately perpendicularly.
The apparatus of Fig. 1 may be used to backlight an advertising poster, traffic sign or other translucent display panel. When the LEDs 12 are powered, light is generated and passes directly into the silicone material 16 in which they are embedded without having to cross an air boundary, The light then passes out of the silicone16 which, due to the concave curving, is focussed (depending on the shape and curvature of the curved upper surface) before passing into the acrylic panel 1 through the edge 1a. the silicone16 shifts the correlated colour temperature (CCT) of the light from the LEDs. The LEDs are therefore selected accordingly. For example if a CCT of 8500 K is desired, LEDs having a CCT of 5000 K are used.
The light travels through the acrylic light guide panel 1 in a planar direction until it strikes the etched lines 20. The etched lines 20 cause the light to scatter out of the front of the light guide panel 1 and onto the translucent display panel, thereby illuminating it from behind.
It will be appreciated that the curved surface of the silicone 16 thus provides a lensing effect. This allows, along with the non-uniform pattern of the etched lines 20 on the back of the acrylic light guide panel 1, a better spread of light to be achieved. The spread of light can also be tailored, for example to throw more light towards the centre of the panel 1. Similarly, together with control electronics (not shown) which determine which of the LEDs is illuminated, parts of the panel 1 can be made brighter than others. This can be used for example to highlight a particular portion of the panel corresponding to part of the printed material at the front of the poster case which it is desired to draw particular attention to.
The LEDs can be selected to give overall white light (either individually or in combination) or indeed any other colour or mix of colours can be provided. Again with selective illumination, different colour effects can be achieved.
Control of the illumination could be handled entirely autonomously by the display apparatus but equally a communications system could be provided to allow for external control signals to be used. This could be wired or wireless - e.g. using WiFi, Bluetooth ™, mobile cellular data signals or the like. This facilitates changing of the illumination pattern to suit new printed materials.
Fig. 4 shows an alternative embodiment. Here the light generating modules 102 are at the top and bottom of the acrylic light guide panel 101, supplied by a power supply unit 105, loom 106 and connectors 106a. The main difference is this embodiment is that rather than a single static sheet of printed material in front of the illumination module, a length of printed material is provided which is selectively wrapped around upper and lower rollers 120, 122 so that by rotating one or both of the rollers, the visible information appearing can be changed.
Fig. 5 shows an alternative embodiment of the acrylic light guide panel 201 and light generating module 202. This comprises an aluminium frame member 208 as before, however in this embodiment the outer surface of the potting resin 216 in which the LED strip 212 is embedded is convex rather than concave. The edge 201a of the acrylic panel is accordingly concave rather than convex. This still allows for close optical coupling between the LED carrier 214 and the acrylic panel edge 201 but provides a different lensing effect. This can also be influenced by different patterns etched on the acrylic light guide panel 1. Of course any combination of convex and concave portions could be used.
Thus it will be appreciated by those skilled in the art that certain specific embodiments have been described which give advantages of more efficient illumination, easier installation and greater flexibility in use. Many variations and modifications are however possible within the scope of the invention.

Claims (13)

Claims:
1. An illumination module for a display apparatus, said illumination module comprising a light guide panel and at least one light generating module arranged at an edge of said light guide panel, said light generating module comprising a plurality of light emitting diodes fully embedded in a light transmissive material, an outer surface of said light transmissive material having one or more portions which is/are curved so as to redirect light from said LEDs.
2. An illumination module as claimed in claim 1 wherein the outer surface of the light transmissive material is in physical contact with an edge of the light guide panel.
3. An illumination module as claimed in claim 2 wherein the edge of the light guide panel has a complementary curved portion to allow a close fit to the light transmissive material.
4. An illumination module as claimed in any preceding claim wherein the light generating module comprises a releasable connector for making electrical connection to the rest of said display apparatus.
5. An illumination module as claimed in any preceding claim wherein the light generating module comprises constant current drivers for the LEDs.
6. An illumination module as claimed in any preceding claim wherein a surface of the light guide panel is etched with a plurality of lines to promote light dispersion therefrom.
7. An illumination module as claimed in claim 6 said lines are parallel but non-uniformly spaced.
8. An illumination module as claimed in any preceding claim wherein the light guide panel is made of acrylic.
9. An illumination module as claimed in any preceding claim wherein the illumination module comprises a carrier providing the LEDs and light transmissive material and a heat sink in good thermal contact with the carrier.
10. An illumination module as claimed in any preceding claim wherein the light transmissive material acts to provide an offset in correlated colour temperature to the light emitted by the LEDs.
11. A display apparatus comprising at least one translucent display surface, and an illumination module as claimed in any receding claim arranged to illuminate said translucent display surface.
12. An illumination module substantially as hereinbefore described with reference to the accompanying drawings.
13. A display apparatus substantially as hereinbefore described with reference to the accompanying drawings.
GB1512310.2A 2015-07-14 2015-07-14 Illuminated displays Withdrawn GB2540378A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1512310.2A GB2540378A (en) 2015-07-14 2015-07-14 Illuminated displays

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1512310.2A GB2540378A (en) 2015-07-14 2015-07-14 Illuminated displays

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GB201512310D0 GB201512310D0 (en) 2015-08-19
GB2540378A true GB2540378A (en) 2017-01-18

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE202020101201U1 (en) * 2020-03-04 2021-06-07 Motherson Innovations Company Limited Connection arrangement for connecting an LED module to a light guide which is arranged in an illuminated vehicle part of a vehicle, as well as an illuminated vehicle part and vehicle with such a connection arrangement

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000348517A (en) * 1999-06-07 2000-12-15 Stanley Electric Co Ltd Light emitting device
US20080062715A1 (en) * 2006-09-08 2008-03-13 Samsung Electronics Co., Ltd. Backlight assembly and liquid crystal display having the same
WO2008062812A1 (en) * 2006-11-21 2008-05-29 Showa Denko K.K. Light emitting device and surface light emitting device
US20090297090A1 (en) * 2005-09-30 2009-12-03 Osram Opto Semiconductors Gmbh Illumination Unit Comprising Luminescence Diode Chip and Optical Waveguide, Method for Producing an Illumination Unit and LCD Display
US20100142200A1 (en) * 2008-12-05 2010-06-10 Hon Hai Precision Industry Co., Ltd. Lens, lens array having same and light source module having same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000348517A (en) * 1999-06-07 2000-12-15 Stanley Electric Co Ltd Light emitting device
US20090297090A1 (en) * 2005-09-30 2009-12-03 Osram Opto Semiconductors Gmbh Illumination Unit Comprising Luminescence Diode Chip and Optical Waveguide, Method for Producing an Illumination Unit and LCD Display
US20080062715A1 (en) * 2006-09-08 2008-03-13 Samsung Electronics Co., Ltd. Backlight assembly and liquid crystal display having the same
WO2008062812A1 (en) * 2006-11-21 2008-05-29 Showa Denko K.K. Light emitting device and surface light emitting device
US20100142200A1 (en) * 2008-12-05 2010-06-10 Hon Hai Precision Industry Co., Ltd. Lens, lens array having same and light source module having same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE202020101201U1 (en) * 2020-03-04 2021-06-07 Motherson Innovations Company Limited Connection arrangement for connecting an LED module to a light guide which is arranged in an illuminated vehicle part of a vehicle, as well as an illuminated vehicle part and vehicle with such a connection arrangement

Also Published As

Publication number Publication date
GB201512310D0 (en) 2015-08-19

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)