WO2004018063A1

WO2004018063A1 - Interconnectable building blocks

Info

Publication number: WO2004018063A1
Application number: PCT/GB2003/003602
Authority: WO
Inventors: Stephen Heeks; Jonathan Halls
Original assignee: Cambridge Display Technology Limited
Priority date: 2002-08-21
Filing date: 2003-08-15
Publication date: 2004-03-04
Also published as: GB2408466B; AU2003267550A1; GB0219435D0; GB0503421D0; GB2408466A

Abstract

The present invention is directed to interconnectable building blocks (100) suitable for use in a toy building set. The building blocks comprise at least one coupling pin (102) or at least one counter coupling socket and an organic optoelectronic device (101). Preferred organic optoelectronic devices include organic light emitting devices (202) and organic photovoltaic devices (210).

Description

INTERCONNECTABLE BUILDING BLOCKS

Background of the invention

Field of the invention

The present invention relates to interconnectable building blocks suitable for use in a toy building set, the building blocks comprise an organic optoelectronic device such as an organic light emitting device or an organic photovoltaic device.

Brief description of the prior art

Constructional building sets of interconnectable building blocks are well known. A particularly successful class of interconnectable building blocks, sold under the trade name LEGO^®, comprises building blocks with complementary sets of coupling pins and counter coupling sockets on opposite sides of the blocks. To improve the attractiveness of such building sets and to enhance their educational value a number of efforts have been made to introduce additional functionality into these building sets. Examples include interconnectable building blocks having electrical conductors and electrical contacts, as disclosed in US5848503, interconnectable building blocks having energy accumulators and, for example, electrical lamps driven by the accumulated energy, as disclosed in WO00/41790, interconnectable building blocks with solar cells, as disclosed in US4199894 and interconnectable building blocks with inorganic light emitting diodes, as disclosed in DE19853424.

A number of disadvantages associated with the aforementioned prior art functionalised building blocks have prevented their widespread uptake by the market. The size and shape of the electronic components are generally not suitable for incorporation into standard building block systems, requiring the production of specialised, expensive building blocks and the modification of production lines. Moreover the electronic components of prior art functionalised building blocks are not integral to the building blocks and may become separated from the blocks, this prevents the correct functioning of the blocks and may be hazardous to the user.

There exists a need for an interconnectable building block and a stacking block system which enables the safe introduction of functionalities such as light and electricity generation into the building blocks yet still enables the blocks to be lightweight and readily manufacturable.

Summary of the invention

The present invention overcomes a number of the problems associated with prior art functionalised interconnectable building blocks. In a first embodiment the present invention provides an interconnectable building block, suitable for use in a toy building set, comprising at least one coupling pin or at least on counter coupling socket characterised in that said interconnectable building block further comprises an organic optoelectronic device. An interconnectable building block according to the present invention may further comprise at least one coupling pin and at least one counter coupling socket.

Organic light emitting devices and organic photovoltaic devices are preferred classes of organic optoelectronic devices for use in the present invention. Organic light emitting devices comprise a layer of organic light emitting material situated between two electrodes, the organic light emitting material emits light on the passage of a current between the electrodes. Organic photovoltaic devices comprise a layer of organic photovoltaic material situated between two electrodes, the organic photovoltaic material generates a current when ambient light is incident on the device. In both organic light emitting devices and organic photovoltaic devices it is preferred that at least one of the two electrodes is transparent. Organic light emitting devices are disclosed in WO90/13148 and organic photovoltaic devices are disclosed in US5670791. A preferred organic optoelectronic device comprises a semi- conductive organic polymer, in particular a light emitting semi-conductive organic polymer or a photovoltaic semi-conductive organic polymer.

The present invention overcomes a number of the problems of prior art functionalised building block systems. Organic optoelectronic devices have a monolithic structure which enables them to be integrated with building blocks with the use of relatively few components. Organic optoelectronic devices have a thin film structure which allows them to be integrated into, or laminated onto, building blocks while necessitating relatively little modification of the building blocks. Both the use of fewer components and also the possibility of suitably modifying the materials used in the organic optoelectronics devices means that building blocks with integrated organic optoelectronic devices present fewer hazards to the user. Organic optoelectronic devices and in particular organic diodes may be manufactured using many of the same process steps, enabling building blocks with a variety of functions to be manufactured without requiring specialised manufacturing facilities for each function. Furthermore organic optoelectronic devices are generally thinner, lighter weight and consume less power than the inorganic optoelectronic devices which are used in the prior art, making their use in interconnectable building blocks particularly advantageous since interconnectable building blocks will in general be small in size and for safety reasons should only require a relatively low voltage or draw a relatively low current.

In order to provide electrical power to, or draw electrical power from, the interconnectable building blocks of the present invention it is preferred that the some of the coupling pins comprise an electrical contact or some of the counter coupling sockets comprise an electrical contact or that some of both the coupling pins and the counter coupling sockets comprise electrical contacts.

To prevent damage to the active components of the organic optoelectronic device in which the coupling pin and the counter coupling socket comprises electrical contacts, the interconnectable building blocks may further comprise a means for protection against reverse polarity.

The organic optoelectronic device of the present invention may be integral to the interconnectable building block or may be attached to the exterior of the interconnectable building block

In a further embodiment the present invention provides a stacking building block system, suitable for use as a toy set, comprising a plurality of interconnectable building blocks according to a first embodiment of the present invention, further comprising electrical contacts between said interconnectable building blocks.

In a further embodiment the present invention provides a stacking building block system, suitable for use as a toy set, comprising a plurality of interconnectable building blocks according to a first embodiment of the present invention, further comprising a motherboard, said motherboard comprising at least one coupling pin or at least one counter coupling socket, with electrical contacts between said interconnectable building blocks and said motherboard. In a further embodiment the present invention comprises a kit comprising an interconnectable building block, suitable for use in a toy building set, said interconnectable building block comprising at least one coupling pin or at least one counter coupling socket and said kit further comprising an organic optoelectronic device suitable for attachment to said interconnectable building block.

Detailed description of the invention

Brief description of the drawings

Figure 1 shows an interconnectable building block according to the present invention.

Figure 2a) illustrates an organic light emitting device.

Figure 2b) illustrates an organic photovoltaic device.

Figure 3) shows a motherboard suitable for use in an embodiment of the present invention.

Description of preferred embodiments

Figure 1 shows an interconnectable building block 100 according to the present invention. The interconnectable building block has four sidewalls, and an upper 103 and a lower surface. The organic optoelectronic device 101 is situated on one of the sidewalls. Alternatively the optoelectronic device may be situated on a number of sides of the building block or alternatively on the upper or lower surface of the building block. The interconnectable building block 100 also comprises a series of coupling pins 102, the coupling pins allow the building block to be connected to other building blocks having suitable counter coupling sockets. Buildings blocks may have either coupling pins, counter coupling sockets or both. In Figure 1 the coupling pins are shown situated on the upper surface of the building block, coupling pins or counter coupling sockets may also be situated on the sidewalls or lower surface of the block. The interconnectable building block of the present invention may be any suitable shape as known in the art, including in the form of a rectangular brick, a square brick, an L-shaped brick, a sloping tile, a flat tile etc. The interconnectable building block may be formed out of any suitable material such as wood, glass, metal, ceramic or plastic. Plastic is a particularly suitable material for such building blocks, in particular thermoset plastics such as ABS (acrylonitrile-butadiene-styrene). As will be readily apparent to one skilled in the art, the interconnectable building blocks of the present invention may be stacked together or with prior art interconnectable building blocks to form a variety of constructions, including static constructions and mobile constructions.

The organic optoelectronic device of the present invention may comprise an organic light emitting device, an organic photovoltaic device, an organic photoluminescent device or an organic electronic device such as an organic transistor. In particular organic light emitting devices and organic photovoltaic devices are preferred and a wide range of applications of these devices may be envisaged.

Figure 2a) shows an organic light emitting device 200. Organic light emitting devices comprise a layered structure comprising a lower electrode 201 , generally situated on a substrate, a layer, or several layers, of organic light emitting material 202 and an upper electrode 203. When a voltage is supplied across the electrode of the device opposite charge carriers, namely electrons and holes, are injected into the organic light emitting material. The electrons and holes recombine in the layer of organic light emitting material resulting in the emission of light. One of the electrodes, the anode, comprises a high work function material suitable for injecting holes into the layer of organic light emitting material, this material typically has a work function of greater than 4.3 eV and may be selected from the group comprising indium-tin oxide (ITO), tin oxide, aluminum or indium doped zinc oxide, magnesium-indium oxide, cadmium tin-oxide, gold, silver, nickel, palladium and platinum. The anode material is deposited by sputtering or vapour deposition as appropriate.

The other electrode, the cathode, comprises a low work function material suitable for injecting electrons into the layer of organic light emitting material. The low work function material typically has a work function of less than 3.5 eV and may be selected from the group including Li, Na, K, Rb, Be, Mg, Ca, Sr, Ba, Yb, Sm and Al. The cathode may comprise an alloy of such metals or an alloy of such metals in combination with other metals, for example the alloys MgAg and LiAI. The cathode preferably comprises multiple layers, for example Ca/AI, Ba/AI or LiAI/AI. The device may further comprise a layer of dielectric material between the cathode and the emitting layer, such as is disclosed in WO 97/42666. In particular it is preferred to use an alkali or alkaline earth metal fluoride as a dielectric layer between the cathode and the emitting material. A particularly preferred cathode comprises LiF/Ca/AI, with a layer of LiF of thickness from 1 to 10nm, a layer of Ca of thickness of 1 to 25nm and a layer of Al of thickness 10 to 500nm. Alternatively a cathode comprising BaF₂/Ca/AI may be used. The cathode materials are deposited by vacuum deposition methods.

For light emission to occur from the device the cathode, the anode or both should be transparent or semi-transparent, although edge emission from the device also occurs when both electrodes are opaque. Suitable materials for transparent anodes include ITO and thin layers of metals such as platinum. Suitable materials for transparent cathodes include a thin layer of electron injecting material in proximity to the layer of organic light emitting material and a thicker layer of transparent conductive material overlying the layer of electron injecting material e.g. a cathode structure comprising Ca/Au.

The organic light emitting materials include polymeric light emitting materials, such as disclosed in Bernius et al Advanced Materials, 2000, 12, 1737, low molecular weight light emitting materials such aluminum trisquinoline, as disclosed in US5294869, light emitting dendrimers as disclosed in WO99/21935 or phosphorescent materials as disclosed in WO00/70655. The light emitting material may comprise a blend of a light emitting material and a fluorescent dye or may comprise a layered structure of a light emitting material and a fluorescent dye. Due to their processability soluble light emitting materials are preferred, in particular soluble light-emitting polymers. Light emitting polymers include polyfluorene, polybenzothiazole, polytriarylamine, poly(phenylenevinylene) and polythiophene. Preferred light emitting polymers include homopolymers and copolymers of 9,9-di-n-octylfluorene (F8), N,N-bis(phenyl)-4-sec- butylphenylamine (TFB) and benzothiadiazole (BT).

The organic light emitting device may include further organic layers between the anode and cathode to improve charge injection and device efficiency. In particular a layer of hole-transporting material may be situated over the anode. The hole- transport material serves to increase charge conduction through the device. The preferred hole-transport material used in the art is a conductive organic polymer such as polystyrene sulfonic acid doped polyethylene dioxythiophene (PEDOT:PSS) as disclosed in WO98/05187, although other hole transporting materials such as doped polyaniline or TPD (N,N'-diphenyl-N,N^,-bis(3-methylphenyl)[1 ,1'-biphenyl]-4,4'- diamine) may also be used. A layer of electron transporting or hole blocking material may be positioned between the layer of light emitting material and the cathode if required to improve device efficiency.

Organic photovoltaic devices, 210 Figure 2b), have a similar structure to organic light emitting diodes comprising a layer of organic photoconductive material 212 between an anode 211 and a cathode 213. Organic heterojunction photovoltaic devices are a particular class of organic photovoltaic devices and operate in the manner described as follows. The electrodes of different work function set up an internal electric field across the device. The organic layer comprises a mixture of a material having a higher electron affinity and a material having a lower electron affinity. Absorption of light by the materials of the organic layer generates bound electron-hole pairs, termed excitons. Excitons generated on the material of lower electron affinity dissociate by transfer of an electron to the material of higher electron affinity, the material of lower electron affinity is sometimes referred to as the electron donor or simply donor. Excitons generated on the material of higher electron affinity dissociate by transfer of a hole to the material of lower electron affinity, the material of higher electron affinity is sometimes referred to as the electron acceptor or simply acceptor. The electrons and holes generated by dissociation of the exictons then move through the device, with electrons moving to the lower work function cathode and holes moving to the higher work function anode. In this way light incident on the device generates a current which may be used in an external circuit.

Suitable anode and cathode materials for an organic photovoltaic device are those described above for an organic light emitting device. Organic heterojunction photovoltaic diodes are currently one of the most efficient types of organic photovoltaic devices and are disclosed in US5331183. A variety of structures of the organic photovoltaic devices are possible. The electron donor and electron acceptor may comprise polymers or low molecular weight compounds. The electron donor and acceptor may be present as two separate layers, as disclosed in WO99/49525, or as a blend or so called bulk heterojunction, as disclosed in US5670791. The electron donor and acceptor may be selected from perylene derivatives such as N, N'- diphenylglyoxaline-3, 4, 9, 10-perylene tetracarboxylic acid diacidamide, fullerenes (C₆o), fullerene derivatives and fullerene containing polymers and semiconducting organic polymers such as polyfluorenes, polybenzothiazoles, polytriarylamines, poly(phenylenevinylenes), polyphenylenes, polythiophenes, polypyrroles, polyacetylenes, polyisonaphthalenes and polyquinolines. Preferred polymers include MEH-PPV (poly(2-methoxy, 5-(2'-ethyl)hexyloxy-p-phenylenevinylene)), MEH-CN- PPV (poly (2,5-bis (nitrilemethyl)-l- methoxy-4- (2'-ethyl-hexyloxy) benzene-co-2,5- dialdehyde-l-methoxy4- (2'-ethylhexyloxy) benzene)) and CN-PPV cyano substituted PPV, polyalkylthiophenes, such as poly(3-hexylthiophene), POPT poly(3 (4- octylphenyl)thiophene) and poly(3-dodecylthiophene), polyfluorenes, such as poly(2,7-(9,9-di-n-octylfluorene), poly(2,7-(9,9-di-n-octylfluorene)-benzothiadiazole) and poly(2,7-(9,9-di-n-octylfluorene)-(4,7-di-2-thienyl-(benzothiazole)). Typical device structures include a blend of N, N'-diphenylglyoxaline-3, 4, 9, 10-perylene tetracarboxylic acid diacidamide and poly(3-dodecylthiophene), a layered structure comprising a layer of MEH-PPV and a layer of C₆o, a blend of MEH-PPV and C₆₀, a layered structure comprising a layer of MEH-CN-PPV and a layer of POPT, a blend comprising MEH-PPV and CN-PPV and a blend comprising poly(3-hexylthiophene) and poly(2,7-(9,9-di-n-octylfluorene)-(4,7-di-2-thienyl-(benzothiazole)). Organic photovoltaic devices may comprised auxiliary organic layers between the electrodes for improving charge collection and transport.

Organic optoelectronic devices may be prepared by any suitable method known to those skilled in the art. Typically the substrate will comprise a glass sheet, a layer of anode material, such as ITO, may be deposited by sputtering. The ITO or other anode material may, if required, be patterned using either additive methods during deposition, such as printing, or using subtractive methods following deposition, such as photolithography. The organic layers of the device may be deposited by vapour deposition, this is a particularly suitable method for the deposition of low molecular weight organic optoelectronic materials. Where the organic optoelectronic materials are soluble they may be advantageously deposited by solution processing techniques. Solution processing techniques include selective methods of deposition such as screen printing and ink-jet printing and non-selective methods such as spin coating and doctor blade coating. Organic semiconductive polymers are particularly suited to deposition using ink-jet printing, as disclosed for example in EP0880303. The cathode and any additional dielectric layers may be deposited using vapour deposition. Auxiliary layers and features may be included in the organic optoelectronic device as appropriate to improve charge injection or to facilitate patterning of the device.

In order to provide power to the optoelectronic device or to draw power from the optoelectronic device electrical contacts are provided to the device. In the case of organic light emitting diodes and organic photovoltaic devices electrical contacts are provided to the electrodes of these devices. It is known in the art to provide electrical contacts through the coupling means used to connect the interconnectable building blocks. The electrical contact may be provided as a free standing conducting wire which runs through the blocks entering and exiting at suitable points on the coupling pins and counter coupling sockets. Alternatively the electrical contact may be provided by a conductive trace on the surface of, or embedded into, the building block, such a conductive trace may run between the coupling pins and the counter coupling sockets.

Where the organic optoelectronic device is situated on the outer surface of the building block connections may be made to the device through electrical traces running over the outer surface of the building block from the coupling pins or counter coupling sockets to the electrodes of the organic optoelectronic device. Organic optoelectronic devices may also be connected by electrical contacts which run through the building block to the interior of the block.

Protection may be provided to prevent a voltage of the wrong polarity being put across the optoelectronic device when the interconnectable building blocks are assembled or connected to a power supply. Suitable protection may comprise protection diodes electrically connected to, and possibly built into, the building blocks. A mechanical means of protection may also be used, for example by providing a means on the interconnectable building blocks which only allows them to be stacked, and thereby electrically coupled, in a particular orientation. In order to protect the user and the active modules a means may be provided to limit the voltage which may be applied to the interconnectable building block or the interconnectable building block system.

Interconnectable building blocks of the present invention may have the optoelectronic device situated integral to the block or the device may be laminated onto the exterior of the block. The term integral includes building blocks where the optoelectronic device forms part of the building block, for example where a side wall of the building block acts as the substrate of the optoelectronic device, and building blocks where the optoelectronic device is, for example, set into a suitable recess in the block. To form interconnectable building blocks comprising an integral optoelectronic device a layer of conducting material suitable to form a first electrode is deposited upon the building block, a layer of organic optoelectronic material is deposited over the first electrode, for example by vacuum deposition, or preferably by a solution processing technique such as spin-coating, doctor blade coating or ink-jet printing and a further layer of conducting material is deposited over the layer of organic optoelectronic material to form a second electrode. The optoelectronic device may also be encapsulated, for example by depositing an impermeable barrier layer over the device. Where a device as described is an organic light emitting device or an organic photovoltaic device the second electrode should be at least partially transparent. In cases where a pre-formed optoelectronic device is fitted into a building block the optoelectronic device may be prepared by the techniques commonly used in the art.

Where the organic optoelectronic device is laminated onto the building block the optoelectronic device may be prepared by techniques commonly known in the art. A particularly suitable organic optoelectronic device for laminating onto interconnectable building blocks comprises a flexible substrate, a first electrode, a layer of organic optoelectronic material, a second electrode and an impermeable barrier layer covering the second electrode, an impermeable barrier layer may also be provided over the substrate. Such a flexible device may conform to the shape of the building block. The optoelectronic device may be attached to the building block using a suitable adhesive such as an ultraviolet or heat curing adhesive. Optoelectronic devices often comprise a glass substrate, for safety reasons means may be used to protect the user in the event of the glass substrate being damaged. Where the optoelectronic device comprises a separate component set into a recess in the building block the device may be set behind a transparent plastic window to prevent any contact being made to the device. Where the optoelectronic device is laminated onto the exterior of the building block the glass substrate of the optoelectronic device may be suitably formed from a glass/plastic composite in which a thin layer of glass is strengthened and prevented from shattering by a thicker plastic support.

The interconnectable building blocks of the present invention may be stacked together or with prior art interconnectable building blocks to form a stacking building block system. In particular the building blocks of the present invention may be combined with electrically conductive prior art building blocks. Interconnectable building blocks comprising organic light emitting devices may be used to form lighting elements or simple displays. Electrical connections to the building blocks may also be used to provide driving signals to the building blocks comprising organic light emitting devices, allowing individual blocks to be switched on and off to form simple information displays and patterns of flashing lights. The electrical connections on the block may allow interfacing to a computer or self-contained remote control to write to the memory of a passive or active matrix display, enabling the display content to be updated.

Interconnectable building blocks of the present invention comprising organic photovoltaic devices may be connected in series, enabling higher voltages to be built up across a number of devices, or in parallel, enabling greater currents to be sourced from the array of photovoltaic devices.

Interconnectable building blocks comprising organic photovoltaic devices may be used to provide power to other components of a stacking building block system. For example the building blocks may be used to provide a source of power to building blocks comprising organic light emitting devices.

A stacking building block system_, according to the present invention may comprise interconnectable building blocks and a motherboard comprising coupling pins or counter coupling sockets. The building blocks may be connected to the motherboard through the pins or sockets, by providing electrical connections through the pins or sockets of the motherboard, the motherboard may be used to provide power to attached lighting blocks or to draw power from attached photovoltaic blocks. Figure 3 illustrates a motherboard 300 which may be used in a stacking interconnectable building block system according to the present invention. The motherboard comprises coupling pins which have a positive polarity 301 or which are grounded 302. The motherboard is connected to a power supply via connector 303. An interconnectable building block which may be used with the motherboard contains diodes which allow the building block to be attached to the motherboard in any orientation whilst still making a suitable electrical connection to the motherboard, such building blocks may be assembled by users with little knowledge of electrical circuits. As an alternative to the use of diodes to prevent incorrect connection the building blocks may have a physical means to prevent incorrect connection.

The interconnectable building blocks of the present invention have application in both leisure and educational settings, in particular the interconnectable building blocks may educate users on such subjects as simple electrical circuits and components and renewable energy, energy efficiency and conservation. Examples of the uses of interconnectable building blocks of the present invention includes toy road signs, solar roof tiles, illumination panels, back-lit stencils/legends, miniature simulated TV/ computer display screens, headlamps, scrolling/flashing advertising signs, etc. No doubt many other effective alternatives will occur to the skilled person. It will be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the spirit and scope of the claims appended hereto.

Claims

1. An interconnectable building block, suitable for use in a toy building set, comprising at least one coupling pin or at least one counter coupling socket characterised in that said interconnectable building block further comprises an organic optoelectronic device.

2. An interconnectable building block according to claim 1 further comprising at least one counter coupling pin and at least one counter coupling socket.

3. An interconnectable building block according to any preceding claim wherein said organic optoelectronic device comprises an organic light emitting device.

4. An interconnectable building block according to claim 1 or claim 2 wherein said organic optoelectronic device comprises an organic photovoltaic device.

5. An interconnectable building block according to any preceding claim wherein said organic optoelectronic device comprises a semi-conductive organic polymer.

6. An interconnectable building block according to any preceding claim wherein said coupling pin comprises an electrical contact.

7. An interconnectable building block according to any preceding claim wherein said counter coupling socket comprises an electrical contact.

8. An interconnectable building block according to any preceding claim wherein said coupling pin and said counter coupling socket comprise electrical contacts and said interconnectable building block further comprises a means for protection against reverse polarity.

9. An interconnectable building block according to any preceding claim wherein said organic optoelectronic device is integral to said interconnectable building block.

10. An interconnectable building block according to any preceding claim wherein said organic optoelectronic device is attached to the exterior of said interconnectable building block.

11. A stacking building block system, suitable for use as a toy building set, comprising a plurality of interconnectable building blocks according to any preceding claim further comprising electrical contacts between said interconnectable building blocks.

12. A stacking building block system, suitable for use as a toy building set, comprising a plurality of interconnectable building blocks according to any preceding claim further comprising a motherboard, said motherboard comprising at least one coupling pin or at least one counter coupling socket, with electrical contacts between said interconnectable building blocks and said motherboard.

13. A kit comprising an interconnectable building block, suitable for use as a toy building set, said interconnectable building block comprising at least one coupling pin or at least one counter coupling socket and said kit further comprising an organic optoelectronic device suitable for attachment to said interconnectable building block.