GB2515845A

GB2515845A - Pixel unit

Info

Publication number: GB2515845A
Application number: GB1317606.0A
Authority: GB
Inventors: Simon Clovis Younger; Christopher G H Courtney
Original assignee: LIGHTGEIST Ltd
Current assignee: LIGHTGEIST Ltd
Priority date: 2013-10-04
Filing date: 2013-10-04
Publication date: 2015-01-07
Also published as: WO2015049536A1; GB201317606D0

Abstract

A display module 1 which forms a pixel unit for a light-emitting visual display (Fig. 3) formed from an array of such modules comprises transmitter and receiver units 8 configured to transmit and receive communication signals within a common plane and one or more light sources 7a-7c, e.g. red, green and blue LEDs, configured to emit light in a direction normal to the common plane. These display modules communicate wirelessly, e.g. using infra-red, with one another. A control unit is provided for controlling the light output of each of the display modules to form desired animations. By configuring the array of pixel units to form a peer to peer network the light-emitting visual display is extremely flexible in its design and quick and simply to deploy and store.

Description

1 Pixel Unit 3 The present invention relates generally to the field of visual displays. A wireless pixel unit 4 is described that finds particular application in the formation of a light-emitting visual display for use at music, corporate, cultural, or large private events or within retail and 6 advertising environments.

8 Background to the Invention

Lighting is used extensively as a communication and entertainment medium at cultural and 11 sporting events across the world. Traditional systems use a fixed system of lights, screens 12 and laser effects to advertise, entertain and inform spectators and to reach a wider 13 audience through television.

IS Current systems deliver light based optical messages in a variety of ways. One method is 16 to deploy screens of LED arrays in small pads of a stadium such as pitch side screens or 17 central scoreboards. Such systems are however relatively inflexible due to the fixed 18 nature of the screens and the inherent physical restrictions of the area of the screens 19 themselves.

1 An alternative method is to employ a visible laser so as to create a display within a large 2 vacant area. This is achieved by projecting or forming an image within this area with the 3 laser. This type of effect requires that the area onto which the image is projected exhibits 4 the correct optical properties and that a surrounding area is comparatively poorly lit so as to provide the required contrast. These requirements significantly restrict the location 6 within which such systems can be deployed.

8 More recently, the London 2012 Olympics opening ceremony employed a visual display 9 that was based on around seventy thousand, 25 centimetre pixel panels that were placed around the stadium, including between every seat. This was a permanent installation that ii required approximately 370km of cabling installed by multiple people over a five week 12 period. Whilst such a system may be commercially viable for an event like the Olympics, it 13 is not a viable option for most cultural or sporting events due to the high costs and 14 installation times involved.

IS

16 It is therefore an object of an embodiment of the present invention to obviate or at least 17 mitigate the foregoing disadvantages of the light-emitting visual display systems known in 18 the art.

It is a further object of an embodiment of the present invention to provide a light-emitting 21 visual display that is highly portable when compared to those light-emitting visual display 22 systems known in the art.

24 Summary of the Invention

26 According to a first aspect of the present invention there is provided a pixel unit suitable for 27 use within a light-emitting visual display, the pixel unit comprising 28 two or more transmitter and receiver units configured to transmit and receive non-parallel 29 communication signals within a common plane, and one or more light sources the light sources configured to emit light in a direction normal to 31 the common plane.

33 The above pixel unit thus provides a source of light suitable for use as a wireless pixel for 34 light-emitting visual display.

1 Most preferably the pixel unit comprises four transmitter and receiver units configured to 2 transmit and receive communication signals within the common plane. This embodiment a allows for communication signals to be transmitted and received in bi-directionally within 4 the common plane.

6 The light sources may comprise one or more light sources selected from a group 7 consisting aired light sources, green light sources, blue light sources and white light 8 sources.

Prof erably the pixel unit comprises a housing having a transparent window through which Ii light from the one or more light sources is emitted.

13 The housing is preferably watertight and may be made from a metal or plastic material.

Preferably one or more locators may be attached to an external surface of the housing.

16 These locators provide a means for assisting in the positing of the pixel unit.

18 The one oi moie locators may comprise a stand pivotally mounted to the housing.

19 Alternatively the one or more locators may comprise one or more suction mounts.

21 Optionally the pixel unit comprises one or more secondary transmitter and receiver units 22 located to transmit and receive communication signals out of the common plane.

24 The communication signals are preferably of a near infrared (IR) wavelength.

26 The pixel unit may further comprise a computer processing unit (CPU). The CPU provides 27 the means for the pixel unit to communicate with other components, e.g. other the pixel 28 units via the combined transmitter and receiver units. Furthermore, the CPU may provide 29 the means for output from the light sources to be controlled.

31 Most preferably the pixel unit comprises a power supply. It is preferable for the power 32 supply to comprise a rechargeable battery. In such embodiments the housing further 33 comprises a connector to facilitate charging of the battery.

1 It is preferable for the pixel unit to further comprise a battery charge indicator. The battery 2 charge indicator may be in the form of visible warning e.g. via one or more of the light 3 sources, or via a communication signal transmitted from a the transmitter and receiver 4 units.

6 According to a second aspect of the present invention there is provided a light-emitting 7 visual display comprising one or more pixel units in accordance with the first aspect of the 8 present invention and a control unit for controlling the light output of the one or more pixel 9 units.

Ii Preferably the one or more pixel units form an array of pixel units. The array of pixel units 12 may be a regular array.

14 Most preferably the array of pixel units is configured to form a peer to peer network.

IS

16 The light-emitting visual display may further comprise a handheld optical device that 17 provides a means to interrogate the one or more pixel units.

19 The handheld optical device may comprise a transmitter and receiver unit and a CPU.

21 Embodiments of the second aspect of the invention may include one or more features 22 corresponding to features of the first aspect of the invention or its embodiments, or vice 23 versa.

According to a third aspect of the present invention there is provided a method of 26 producing a light-emitting visual display the method comprising 27 -establishing a peer to peer network within an array of pixel units; 28 -employing the peer to peer network established within the array of light sources to 29 form a picture or image.

31 Most preferably the pixel units comprise one or more pixel units in accordance with the first 32 aspect of the present invention.

34 Establishing the peer to peer network within the array of pixel units preferably involves wireless communication between the elements of the array of pixel units.

2 This wireless communication may occur when the light-emitting visual display is activated. a

4 Alternatively, the wireless communication may occur as the elements of the array of pixel units are deployed. This embodiment allows a test to be carried out on each pixel unit as it 6 is deployed so as to facilitate a quick and error free construction of the array of pixel units, 7 thus avoiding the need post deployment to fault find gaps in the array.

9 Optionally the method of producing a light-emitting visual display further comprises allocating one or more elements of the array of pixel units with a unique identifier. Ii

12 Most preferably the picture or image is formed by relaying control information for the array 13 of pixel units via a first pixel element of the array.

Preferably the first pixel element of the array then relays the control information to its 16 neighbouring pixel units.

18 Most pieleiably animation is provided to the picture or image by subsequently employing 19 the peer to peer network established within the array of light sources to form a second picture or image.

22 Optionally one or more data compression techniques are applied to the relayed control 23 information.

Most preferably control information for elements of the array of pixel units is prevented 26 from being transmitted further through the peer to peer network once the control 27 information has been actioned.

29 Optionally one or more compression techniques may be employed to compress areas of blocks colour within the array of pixel units.

32 In addition, low frequency changes in elements of the array of pixel units may also be 33 removed to further preserve bandwidth.

1 Embodiments of the third aspect of the invention may include one or more features 2 corresponding to features of the first or second aspect of the invention or its embodiments, 3 or vice versa.

Brief Description of the Drawings

7 There will now be described, by way of example only, various embodiments of the 8 invention with reference to the drawings, of which: Figure 1 presents (a) perspective view and (b) a side view of a pixel unit in accordance ii with an embodiment of the present invention; 13 Figure 2 presents a schematic representation of the pixel unit of Figure 1; is Figure 3 presents three schematic representation of a light-emitting visual display formed 16 from a plurality of the pixel units of Figure 1; and 18 Figure 4 presents a flow chart of the methodology for producing the light-emitting visual 19 display of Figure 3.

21 In the description which follows, like parts are marked throughout the specification and 22 drawings with the same reference numerals. The drawings are not necessarily to scale 23 and the proportions of certain parts have been exaggerated to better illustrate details and 24 features of embodiments of the invention.

26 Detailed Description of Preferred Embodiments

28 A detailed description of a pixel unit 1 in accordance with an embodiment of the present 29 invention will now be described with reference to Figures 1 and 2. In particular Figure 1 presents (a) perspective view and (b) a side view of the pixel unit 1 while Figure 2 31 presents a schematic representation of the pixel unit 1. Axes are presented within Figure 32 1 so as to assist understanding of the orientation of various components, as described in 33 further detail below.

1 The pixel unit 1 can be seen to comprise a cuboid shaped housing 2 upon one of the 2 larger surfaces of which is located a transparent window 3. The transparent window 3 can 3 be seen to lie in a plane parallel to the x-y axes. In the context of the present application 4 the term transparent is relative to the wavelength of the light generated within the pixel unit 1 itself. The housing 2 is preferably watertight and may be made from a metal or plastic 6 material.

8 Preferably one or more locators 4 may be attached to an external surface of the housing 9 so as to provide a means for assisting in the positing of the pixel unit 1 for use, as described in further detail below. In this regard, the rear surface 5 of the housing 2 is that 11 surface opposite to the transparent window 3. In the presently described embodiment, the 12 locators 4 comprise a stand 4a pivotally mounted on the rear surface 5 of the housing, 13 and four suction-mounts 4b, one located in each corner of the rear surface 5.

is Located within the housing is a printed circuit board (PCB) 6 that contains the electrical 16 circuitry for the pixel unit 1. As can be seen from Figure 1(a) and Figure 2 the pixel unit 1 17 comprises sixteen LEDs 7 mounted on the PCB 6: four red 7a (operating in the range 18 620nm to 740nm); four green 7b (operating in the range 520nm to 570nm); and eight blue 19 7c (operating in the range 450nm to 495nm), all configured to emit light primarily parallel the z-axis. LED drive circuits are also mounted on the PCB 6. It will be appreciated by 21 the skilled reader that the number and location of the LEDs 7 may vary from those 22 embodiments presented in Figure 1(a) and Figure 2. In addition the colour of the light 23 sources may be varied e.g. one or more white light sources may alternatively be 24 employed.

26 Combined transmitter and receiver units 8, located at each side face of the housing 2, are 27 also electrically connected to the PCB 6. The combined transmitter and receiver units B 28 are positioned to transmit and receive communication signals 9 from the side surfaces of 29 the housing 2 i.e. those surfaces substantially perpendicular to the both the transparent window 3 and the rear surface 5. In this way the IR signals can be emitted from the pixel 31 unit 1 in all four directions across a plane parallel to the x-y axes, thus making the pixel 32 unit 1 capable of bi-directional communication in this plane, as described in further detail 33 below.

1 Optionally one or more secondary transmitter and receiver units 10 are located within the 2 housing so as to transmit and receive communication signals 9 out of a plane parallel to 3 the x-y axes e.g. the secondary transmitter and receiver units 10 may be located on one or 4 both of the surfaces comprising the transparent window 3 or the rear surface 5.

6 The communication signals 9 are preferably of a near infrared (IR) wavelength (i.e. 7 operating in the range 750nm to 1,400nm, also referred to in the art as Consumer IR).

8 This is the wavelength range commonly used within standard consumer electronic remote 9 controls.

Ii Although the transmitter and receiver units 8 and 10 have been presented as single units it 12 will be appreciated that one or more of these units could be split into a separate transmitter 13 and receiver.

In a further alternative embodiment the pixel unit 1 may comprise just two combined 16 transmitter and receiver units 8, one orientated to transmit and receive along the x-axis 17 and one orientated to transmit and receive along the y-axis. This is a less preferable 18 embodiment to that presented in Figures 1 and 2 since such a pixel unit 1 would not 19 capable of bi-directional communication in the a plane parallel to the x-y axes.

21 A computer processing unit (CPU) 11 is also located within the housing 2. The CPU 11 22 provides the means for the pixel unit 1 to communicate with other components, e.g. other 23 the pixel units L via the combined transmitter and receiver units 8. Furthermore, the CPU 24 11 provides the means for output from the LEDs 7 to be controlled as and when required.

26 A power supply 12 is also located within the housing 2. It is preferable for the power 27 supply 12 to comprise a rechargeable battery. In such embodiments the housing further 28 comprises a connector 13 to facilitate easy charging and removal of the pixel unit 1 from a 29 recharging socket.

31 In this regard, the pixel units 1 are preferably stored in trays or rollable cases in order to 32 assist with transportation and recharging. The pixel units 1 are configured to re-charge 33 while inside these trays or cases from a standard DC supply. The voltage and current 1 regulation electronics required to maintain the battery are also contained within the 2 housing 2.

4 It is preferable for the pixel unit 1 to further comprise a power supply indicator so as to provide a means for identifying a low battery condition for the pixel unit 1. The power 6 supply indicator may be in the form of visible warning via one or more of the LEDs 7 and 7 or via a communication signal 9 transmitted from a the transmitter and receiver units 8.

9 Figure 3 presents three schematic representation of a light-emitting visual display 14 comprising sixteen pixel units 1 formed in a regular 4x4 array 15 and a control unit 16.

11 The control unit 16 may be a standalone intelligent processing unit with wireless optical 12 outputs, or an equivalent software package on a computer with an optical interface.

14 The light-emitting visual display 14 may further comprise a handheld optical device 17 that IS comprises its own combined transmitter and receiver unit 18 and a CPU 19. The handheld 16 optical device 17 provides a means for an operator to interrogate each of the pixel units 1 17 so as to obtain information regarding their battery lifetime, their general health or to check 18 what firmware version the device is presently running. The handheld optical device 17 19 may also provide a means for updating the associated firmware or for recalibrating the pixel unit 1.

22 Figure 4 presents a flow chart of the methodology for producing the light-emitting visual 23 display of Figure 3.

The first step involves establishing a peer to peer network within the array of pixel units 15.

26 This may established when the light-emitting visual displayl 4 is activated and each of the 27 pixel units 1 begin to communicate via their transmitter and receiver units 8 with their 28 neighbouring pixel units 1 so as to identify all of their neighbours. This information is 29 relayed to the control unit 16 so that the location of each of the pixel units 1 in the array can be identified and hence a peer to peer network established.

32 Alternatively, the peer to peer network may be established as the pixel units 1 are laid out 33 by an operator. In this embodiment each pixel unit 1 communicates a signal to the control 34 unit 16 when laid down in the proximity of another pixel unit 1 already connected to the 1 control unit 16. This allows a test to be carried out on each pixel unit 1 as it is deployed so 2 as to facilitate a quick and error free construction of the array of pixel units 15 thus 3 avoiding the need post deployment to fault find gaps in the array 15.

Information is preferably relayed to the control unit 16 via each intermediary pixel unit 1 6 that lies between a particular pixel unit 1 and the control unit 16 within the peer to peer 7 network. Alternatively, information may be relayed to the control unit 16 by each pixel unit 8 1 communicating directly with the control unit 16 via one of its secondary transmitter and 9 receiver unit 10.

11 All of the above processes may be assisted by each of the pixel units 1 being allocated a 12 unique identifier. This process may take place during the manufacture of the pixel unit 1 13 or dynamically via the control unit 16 as each pixel unit 1 establishes a communication link 14 with it.

16 At this stage peer to peer network established within the array of pixel units 15 can be 17 used to form a picture or image by the control unit 16. A single frame is formed on the 18 array of pixel units 15 by information being transmitted from the control unit 16 to a first 19 pixel unit 1, in the presently described embodiment this is the pixel unit 1 containing the reference 1', see Figure 3(a). This pixel unit 1 then relays on the relevant information to 21 its neighbours i.e. the pixel units 1 containing the references 2x' and 2y', see Figure 3(b).

22 This process is again repeated so that the relevant information now reaches the pixel units 23 1 containing the references 3x', 3y' and 2xy', see Figure 3. This fanning out of 24 information continues until each pixel unit 1 receives its control information. Thereafter, each pixel unit 1 effectively acts as a pixel for the light-emitting visual displayl4. The 26 control unit 16 turns all of these individual lights into a picture by changing what lights are 27 on or off depending on what color that part of the picture calls for.

29 Since the control unit 16 knows the location and number of pixel units 1 that comprises the light-emitting visual display 14 it is able to dynamically adjust the size and form of the 31 image or picture to be formed.

33 The image or picture can also be animated or changed by simply repeating the above 34 process so as to refresh the image projected from the array of pixel units 15. By 1 refreshing the array of pixel units 15 at various times per second, a still picture can turn 2 into a moving picture. The laster the refresh rate, the smoother the picture will animate.

3 The presently described light-emitting visual displayl4 has a refresh rate of 5 Hz.

To increase the efficiency of the light-emitting visual displayl4 it has been found beneficial 6 for the communications bandwidth of the combined transmitter and receiver units B to be 7 optimised using compression techniques matched to the bandwidth available. In addition, 8 the control unit 16 can be employed to limit control signals to pixel units 1 or pixels that are 9 not changing so as to conserve bandwidth. Furthermore, the control unit 16 can dictate that messages that are destined for topographically close pixel units 1 will not be relayed Ii further through the peer to peer network than is necessary.

13 Techniques such as Huffman encoding may also be employed to compress areas of 14 blocks colour. When deemed necessary, low frequency changes in pixel colour and or is brightness may also be removed to further preserve bandwidth. Additional communication 16 bandwidth may also be made available by the illumination of sub-arrays of pixel units 1 17 with a separate modulated spotlight. The secondary transmitter and receiver units 10 of 18 the pixel units 1 allows for this additional niode of communication.

It will be readily apparent to the skilled reader that in alternative embodiments the number 21 of pixel units 1 may be more or less than the sixteen shown in Figure 3 and that they may 22 be arranged in a wide variety of regular and irregular patterns.

24 The stands 4a of the pixel units 1 provide a means for each pixel unit 1 to be tilted in a specific direction whilst maintaining communication with their nearest neighbours. This 26 means that the image of the light-emitting visual displayl4 can be delivered from a sloping 27 surface e.g. a sloping lawn. In a similar manner the suction-mounts 4a provide a means 28 for the image of the light-emitting visual display 14 to be delivered from a vertical surface 29 e.g. a glass window or other part of a building structure.

31 One significant benefit of the wireless nature of the light-emitting visual displayl 4 is that 32 there is no need for the distance between neighbouring pixel units 1 to be fixed. As a 33 result the layout of the pixel units 1 can be easily adjusted to take account of 34 foreshortening or key stoning when viewed from an angle.

2 The size of the pixel units 1 is such that it enables them to be placed in rough grass and 3 their weight is sufficient to hold them in place in inclement conditions.

In situations that necessitate agap in the line of sight between two pixel units 1, an optic 6 fibre attachment may be employed to maintain connectivity.

8 A further significant advantage results from the bidirectional nature of the communication 9 between the pixel units 1. As a direct consequence the array of pixel unit s 15 is able to adapt to any pixel unit 1 failure, other than the one in direct communication with the control Ii unit 16, so as to re-route communications via other pathways.

13 From the above description it can be seen that the pixel units 1 can be simply laid, or 14 stuck, to any reasonably level surface, a lawn or wall, in any order. This highly flexible and portable nature means the light-emitting visual display 14 can be installed in locations not

16 available to the prior art systems.

18 The pixel units 1 can intelligently locate themselves within a peer to peer network and 19 thereafter employ this position to become a pixel in a large light-emitting visual display 14.

This arrangement makes the described light-emitting visual display 14 highly scalable.

22 As all communication is wireless, the light-emitting visual display 14 can be set up and 23 removed quickly for each event at significantly less cost than those systems known in the 24 art.

26 Cloud based control of the pictures or images appearing on the light-emitting visual display 27 14 is also made possible with above described arrangement.

29 All of the above features combine to make the light-emitting visual display ideally suited for use at music, corporate, cultural, or large private events or within retail and advertising 31 environments.

33 A pixel unit suitable for use within a light-emitting visual display is described. The pixel 34 unit comprises transmitter and receiver units configured to transmit and receive communication signals within a common plane and one or more light sources configured 1 to emit light in a direction normal to the common plane. These pixel units provide a source 2 of light suitable for use as a wireless pixel for light-emitting visual display. Any light- 3 emitting visual display may comprise an array of these pixel units and a control unit for 4 controlling the light output of each of the pixel units. By configuring the array of pixel units to form a peer to peer network provides a wireless light-emitting visual display that is 6 extremely flexible in its design and quick and simply to deploy and store.

8 Throughout the specification, unless the context demands otherwise, the terms "comprise" 9 or "include", or variations such as "comprises" or "comprising", "includes" or "including" will be understood to imply the inclusion of a stated integer or group of integers, but not the Ii exclusion of any other integer or group of integers.

13 Furthermore, reference to any prior art in the description should not be taken as an 14 indication that the prior art forms part of the common general knowledge.

IS

16 The foregoing description of the invention has been presented for purposes of illustration 17 and description and is not intended to be exhaustive or to limit the invention to the precise 18 form disclosed. The described embodiments were chosen and described in order to best 19 explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilise the invention in various embodiments and with various 21 modifications as are suited to the particular use contemplated. Therefore, further 22 modifications or improvements may be incorporated without departing from the scope of 23 the invention as defined by the appended claims.