ELECTRODE ARRANGEMENT FOR ROUND PLED ENABLING RETROFIT Field of invention
[0001] The invention disclosed herein relates, in general, to a new design of organic light emitting device (OLED). More specifically, the invention relates to a planar OLED capable of being retrofitted in conventional lighting fixtures.
Background
[0002] Conventional lighting devices such as incandescent or fluorescent light bulbs are fragile, bulky and problematic to handle and to transport. Further, the incandescent or the fluorescent light bulbs emit approximately 90% of its consumed energy in the form of heat as a byproduct while only about 10% is converted to visible light. The added heat load from the incandescent or fluorescent light bulbs requires high cooling capacity and resultantly higher costs.
[0003] Hence, an alternative for these conventional incandescent or the fluorescent light bulbs was needed and in many applications, the incandescent and the fluorescent light bulbs were gradually replaced by LEDs. LEDs and OLED based lighting usually require lower power which is approximately one-tenth of the requirement for the incandescent or the fluorescent light bulbs for a similar light output.
[0004] A fiirther benefit of OLED light is the planar design, adding a new dimension to designers and home usage. Due to this planar design, OLEDs have a design advantage over LEDs and are more appealing since they provide an illuminating surface instead of a point source provided by the LEDs. The planar light weighted OLED lighting panel has furthermore

the advantage of being easy and cost-effective to ship in comparison to the conventional lighting devices. However, even though the OLED based lighting devices offer several advantages, including reduced energy consumption and improved performance, the problems associated with cost and lifetime still exist. Another drawback of the OLED based lighting devices is the cost and inconvenience of removing conventional lighting device fixtures and installing new light fixtures that are designed and optimized for the OLED based lighting devices. [0005] In order to overcome this additional expense, attempts have been made to retrofit the OLED based lighting devices into the conventional lighting device fixtures. For example, it has been proposed to provide a contact design for removable squared OLEDs to fit in conventional sockets. Such a design is usually rectangular in shape and that use side connects, by which the final design ends up like a square with side lobs. Another technique that has been proposed is placing an OLED inside a tube light or a light bulb. These retrofitting techniques solve OLED retrofit connection issues with respect to earlier proposed OLED based lightings. However, these retrofitting techniques used so far fail to address one or more of functional differences between the OLED based lighting devices and the conventional lighting devices. Especially the planar OLED design is not fully used, having side lobs or using a spherical or tube design. In light of the above discussion, there is a need for an improvement in the structure of the OLED based lighting devices in order to eliminate one or more drawbacks of the prior art.
Summary of the invention
[0006] The instant exemplary embodiments provide an efficient organic light emitting device (OLED) for retrofitting in conventional lighting device fixtures.

10007] Another object of the present invention is to enable retrofitting a circular or a
polygonal shaped OLED that is capable of replacing previously used conventional lighting
devices like incandescent or fluorescent light bulbs or the like.
[0008] An object of the present invention is to provide a circular OLED that is less bulky
and can be conveniently installed in conventional lighting device fixtures.
[0009] Another object of the present invention is to provide a circular shaped bottom
emitting OLED for retrofitting in conventional lighting device fixtures.
[0010] Another object of the present invention is to provide a circular shaped top emitting
OLED for retrofitting in conventional lighting device fixtures.
[0011] Another object of the present invention is to provide a circular shaped dual side
emitting OLED for retrofitting in conventional lighting device fixtures.
[0012] A further object of the present invention is to provide an OLED circuitry
arrangement that conforms to conventional lighting device fixtures.
[0013] In some embodiments of the present invention, a circular shaped OLED is provided.
The circular shaped OLED also includes a recess at the center of the OLED. Further, the OLED
is made of a stack of layers including a substrate, a first electrode layer, one or more light
emitting layers on the first electrode layer and a second electrode layer provided on the one or
more light emitting layers. Further, the OLED also includes one or more first electrical contacts
and one or more second electrical contacts that are alternately placed around a periphery of the
recess forming a ring-like arrangement around the periphery of the recess. The one or more first
electrical contacts and the one or more second electrical contacts are in contact with the first
electrode layer and the second electrode layer respectively and provide external power supply to
the OLED and enable it to emit light.

[0014] In some embodiments of the present invention, an OLED is provided. The OLED includes a planar substrate having a first side, a second side and a recess. Further, the OLED also includes a first electrode layer provided on the first side of the planar substrate. The OLED also includes one or more light emitting layers on the first electrode layer and a second electrode layer provided on the one or more light emitting layers. The OLED also includes one or more first electrical contacts and one or more second electrical contacts, such that they are alternately placed around a periphery of the recess and form an annular arrangement proximal to the periphery. Further, according to the invention, the one or more first electrical contacts are in contact with the first electrode layer and the one or more second electrical contacts are in contact with the second electrode layer.
Brief description of drawings
[0015] The features of the present invention, which are believed to be novel, are set forth
with particularity in the appended claims. The invention may best be understood by reference to
the following description, taken in conjunction with the accompanying drawings. These
drawings and the associated description are provided to illustrate some embodiments of the
invention, and not to limit the scope of the invention.
[0016] FIG. 1 illustrate a stack of layers in an exemplary OLED in accordance with an
embodiment of the present invention;
10017] FIG. 2 shows the top view of an exemplary OLED, in accordance with an
embodiment of the present invention;
[0018] FIG. 3a shows an illustration of a cross section of the OLED of FIG. 2 across a
section A-A, in accordance with an embodiment of the present invention;

[0019] FIG. 3b shows an illustration of a cross section of the OLED of FIG. 2 across a
section B-B, in accordance with an embodiment of the present invention;
[0020] FIG. 4 shows a view of an exemplary OLED and its correspondence to a
conventional lighting device fixture, in accordance with an embodiment of the present invention;
[0021] FIGs. 5a and 5b show a top view and perspective view of another exemplary OLED
fitted in a conventional lighting device fixture, respectively, in accordance with an embodiment
of the present invention; and
[0022] FIGs. 6a and 6b show a top view and perspective view of an yet another exemplary
OLED fitted in a conventional lighting device fixture, respectively, in accordance with an
embodiment of the present invention.
[0023] Those with ordinary skill in the art will appreciate that the elements in the figures are
illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the
dimensions of some of the elements in the figures are not in proportion relative to other
elements, in order to improve the understanding of the present invention.
[0024] There may be additional structures described in the foregoing application that are not
depicted on one of the described drawings. In the event such a structure is described, but not
depicted in a drawing, the absence of such a drawing should not be considered as an omission of
such design from the specification.
Detail description of the present invention
[0025] Before describing the present invention in detail, it should be observed that the present invention utilizes different apparatus components related to an organic light emitting device. Accordingly the apparatus components have been represented where appropriate by

conventional symbols in the drawings, showing only specific details that are pertinent for an
understanding of the present invention so as not to obscure the disclosure with details that will be
readily apparent to those with ordinary skill in the art having the benefit of the description
herein.
[0026] While the specification concludes with the claims defining the features of the
invention that are regarded as novel, it is believed that the invention will be better understood
from a consideration of the following description in conjunction with the drawings, in which like
reference numerals are carried forward.
[0027] As required, detailed embodiments of the present invention are disclosed herein;
however, it is to be understood that the disclosed embodiments are merely exemplary of the
invention, which can be embodied in various forms. Therefore, specific structural and functional
details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims
and as a representative basis for teaching one skilled in the art to variously employ the present
invention in virtually any appropriately detailed structure. Further, the terms and phrases used
herein are not intended to be limiting but rather to provide an understandable description of the
invention.
[0028] The terms "a" or "an", as used herein, are defined as one or more than one. The
term "another", as used herein, is defined as at least a second or more. The terms "including"
and/or "having" as used herein, are defined as comprising (i.e. open transition). The term
"coupled" or "operatively coupled" as used herein, is defined as connected, although not
necessarily directly, and not necessarily mechanically.
[0029] Referring now to the drawings, there is shown in FIG. 1, a stack of layers in an
exemplary organic light emitting device (OLED) 100. This figure will illustrate the different

layers that are usually present in an OLED, and will provide an illustration of how these layers work together to emit light.
[0030] The OLED 100 is shown to include a substrate 102, an internal light extraction layer 104, a first electrode layer 106, one or more organic layers 108, 110 and 112 that function as one or more light emitting layers, a second electrode layer 114 and a cover substrate 116. [0031] For the purpose of the description, the OLED 100 has been shown to include only those layers that are pertinent to the description of the invention. However, it should be understood that the invention is not limited to the layers listed above. In some cases, the OLED 100 may include additional layers to enhance efficiency or to improve reliability, without deviating from the scope of the invention.
[0032] Some real life examples of the OLED 100 can include, but are not limited to. Organic Light Emitting Diode (OLED), White Organic Light Emitting Diode (W-OLED), Active-matrix Organic Light Emitting Diodes (AMOLED), Passive-matrix Organic Light Emitting Diodes (PMOLED), Flexible Organic Light Emitting Diodes (FOLED), Stacked Organic Light Emitting Diodes (SOLED), Tandem Organic Light Emitting Diode, Transparent Organic Light Emitting Diodes (TOLED), Top Emitting Organic Light Emitting Diode, Bottom Emitting Organic Light Emitting Diode, Fluorescence doped Organic Light Emitting Diode (F-OLED) and Phosphorescent Organic Light Emitting Diode (PHOLED). [0033] The substrate 102 provides strength to the OLED 100, and also acts as the emissive surface of the OLED 100 when in use in case of a bottom side emitting device. The examples of material that can be used for making the substrate 102 include, but are not limited to, glass, flexible glass, polyethylene terephthalate (PET), polycarbonate, polyethylene naphthalate (PEN), and other transparent or translucent material.

[0034] In accordance with the invention, the substrate 102 is a planar substrate, i.e., the substrate 102 has a periphery that is substantially circular in shape. This has not been illustrated in FIG. 1, however can be viewed in detail in FIG. 2 of the present invention. [0035] The first electrode layer 106 and the second electrode layer 114 are used to apply a voltage across the one or more organic layers 108, 110 and 112. In an embodiment, the first electrode layer 106 can be implemented with, for example, transparent conductive oxide (TCO), such as indium tin oxide (ITO). Other examples of TCOs include, but are not limited to. Zinc Oxide, Tin Oxide, Aluminum-doped Zinc Oxide (AZO), Boron doped Zinc Oxide (BZO), Gallium doped Zinc Oxide (GZO), Fluorine doped Tin Oxide (FTO), and Indium Zinc Oxide. In another embodiment, the first electrode layer 106 can be in the form of soluble anodes. Examples of material for soluble anodes include, but are not limited to, Ag-nanowires and Pedot:PSS. Further, in an embodiment, the second electrode layer 114 can be implemented with metals having appropriate work function to make injection of charge carriers, such as calcium, aluminum, gold, lithium, lithium fluoride, magnesium, silver and stacked layers of combination thereof
[0036] The first electrode layer 106 is deposited by Plasma Vapor Deposition (PVD) and the second electrode layer 114 is deposited by Thermal evaporation. In other embodiments, of the invention, the first electrode layer 106 and the second electrode layer 114 can be deposited by using any one of a brush or roller, dispensing, slot dye coating, spin-coating, spray coating, diverse replication techniques, plasma vapor deposition, by evaporation or even printing. [0037] In an arrangement when the first electrode layer 106 is made of a transparent conductive oxide and the second electrode layer 114 is made of a metal for example aluminum, the OLED 100 usually functions as a bottom emitting OLED, i.e. the light emitted by the OLED

100 can be through the substrate 102. Usually, for the bottom emitting device, an external light extraction layer may also be provided to the stack of layers in the bottom emitting OLED. This is an additional layer provided on the substrate 102 on the outside.
[0038] However, in accordance with another embodiment of the present invention, the second electrode layer 114 can also be implemented using two layers, a first layer of a thin metal layer as silver, gold or a transition metal oxide, with on top a transparent highly conductive layer as a ITO or Pedot:PSS in order to make the OLED 100 to function as a top emitting or fully transparent OLED 100 where the light can be emitted through the second electrode layer 114 itself because of the transparency provided by the TCO layer as the TCOs have more than 80% transmittance of incident light and have conductivities higher than 10^ S/cm for efficient carrier transport.
[0039] The one or more organic layers 108,110 and 112 can be implemented with any organic electroluminescent material such as a light-emitting polymer, evaporated small molecule materials, light-emitting dendrimers or molecularly doped polymers. In an embodiment of the invention, the organic layer 108 can function as a red light emitting layer, the organic layer 110 can function as a green light emitting layer and the organic layer 112 can fiinction as a blue light emitting layer. However, it should be appreciated that the color of light being emitted by the one or more organic layers 108,110 and 112 is not restricted to those mentioned here and can be any other color without deviating from the scope of the invention.
[0040] Usually the one or more organic layers 108,110 and 112 are deposited on the first electrode layer 106 and generally, the one or more organic layers 108,110 and 112 are deposited using, evaporation or printing techniques. In another example, the OLED 100 may also include additional layers for functional improvement of the OLED 100, like a hole transport layer, hole

injection layer, hole blocking layer, or an electron transport layer, electron injection layer, electron blocking layer.
[0041] Further, the OLED 100 may also includes an internal light extraction layer 104. Usually, light incident from a high refractive index material onto an interface with a lower refractive index material or medium undergoes total internal reflection (TIR) for all incidence angles greater than the critical angle Be, defined by Gc = sin' (n2/nl), where nl and n2 are the refractive indices of the high refractive index material and low refractive index material, respectively. Due to the same reason, when the light emitted by the organic layers 108,110 and 112 reaches their interface with the substrate 102, a substantial amount of light is reflected back into the organic layers 108,110 and 112. Here, presence of the internal light extraction layer 104 having a texture that is capable of changing the propagation direction of the light emitted by the organic layers 108,110 or 112 at their interface with the substrate 102 helps to reduce the reflection (or TIR) of the light back into the OLED 100.
[0042] The texture on the internal light extraction layer 104 may include geometries having dimensions in the order of the wavelength of the light to facilitate the change in propagation direction of the emitted light by diffraction. The texture on the internal light extraction layer 104 may also include geometries having larger dimensions than the wavelength of the light to facilitate the change in propagation direction of the emitted light by refraction. In other embodiments, change in the propagation direction of the emitted light can be altered by a scattering layer, containing scattering particles. Therefore, presence of the internal light extraction layer 104 having textures or the scattering layer eliminates or reduces the TIR, which further increases the efficiency of the OLED 100.

[0043] As described above, in the OLEDs to facilitate light extraction, there has to be a change in a light propagation direction. The texture or the scattering layer provided to the substrate 102 will cause the change in the light propagation direction. This texture can bring about a change in the light propagation direction by either diffraction or refraction. Usually, the texture having dimensions in the order of a wavelength of the light, change the light propagation direction by diffraction. An example of the texture that change the light propagation direction by diffraction include, but is not limited to, a ID grating and a 2D grating. Whereas, the texture having dimensions larger than a wavelength of the light, usually change the light propagation direction by refraction. Examples of the texture that change the light propagation direction by refraction include, but are not limited to, a lens, a cone, and a pyramid. In other embodiments, wherein the scattering layer is provided, the scattering layer may contains scattering particles with sizes in the region of 10-lOOOnm. Further, examples of the scattering particles can include Ti02, Cr02, or others.
[0044] The cover substrate 116 encapsulates the internal light extraction layer 104, the first electrode layer 106, the one or more organic layers 108,110 and 112 and the second electrode layer 114 between itself and the substrate 102. In some embodiments of the present invention, the cover substrate 116 can be a rigid substrate, with or without internal pocket adhered by an adhesive or a direct deposited barrier layer on top consisting of several stacked thin films. [0045] Those skilled in the art will appreciate that the exemplary OLED 100 may include all or a few components or regions shown in FIG. 1. The exemplary OLED 100 may include components or regions that are not shown here and are not germane to various embodiments of the present invention. For example, without deviating from the scope of the invention, the OLED 100 may also include additional organic layers for emitting different colors of lights.

[0046] Moving on to FIG. 2, there is shown a perspective top view of an exemplary OLED 200, in accordance with an embodiment of the present invention. The OLED 200 is shown to include a planar substrate 202 having a recess 204, a first electrical contact 206, a second electrical contact 208 and a notch 210. The OLED 200 is configured to be retrofitted in conventional lighting device fixtures. Further, the planar-shaped structure of the OLED 200 facilitates the OLED 200 to be less bulky and ensures that the OLED 200 can be conveniently installed in the conventional lighting device fixtures.
[0047] The planar substrate 202 is similar in characteristic to the substrate 102 described in association with FIG.l. Also, different layers of the OLED 200 (not illustrated in this figure) are similar in characteristic to those described in association with the OLED 100 of FIG. 1. [0048] The planar substrate 202 is shown to include a recess 204. The recess 204 is disposed such that it is equidistant from a periphery of the planar substrate 202, i.e., the recess 204 is disposed such that it is at the center of the planar substrate 202. In some embodiments of the present invention, the recess 204 can be offset from the center of the planar substrate 202 as desired, without deviating from the scope of the invention. The recess 204 is formed as an elongated opening having a length and a width sufficiently sized to allow passing of a holder present in a conventional lighting device socket. In an embodiment, the material of a holder may be plastic or ceramic. Further, in an embodiment, the recess 204 is formed such that it also has a circular shape. However, it should be appreciated that the shape of the recess is not limited to circular and the recess can also have other shapes without deviating from the scope of the present invention.
[0049] The first electrical contact 206 and the second electrical contact 208 are arranged alternately around a periphery of said recess 204 of the planar substrate 202. This arrangement is

such that they form an annular or ring type arrangement proximal to said periphery of said recess
204. The first electrical contact 206 and the second electrical contact 208 are mounted around the
periphery of the recess and are secured to the substrate of the OLED 200 for coupling electrode
layers of the OLED 200 to an external power supply in order to enable the OLED 200 to emit
light.
[0050] The first electrical contact 206 and the second electrical contact 208 may be
electrically connected to the first electrode layer and the second electrode layer respectively (not
shown in this figure). Further, the first electrical contact 206 and the second electrical contact
208 may be configured to provide an electrical connection between the electrode layers of the
OLED 200 and a power supply.
[0051] In an embodiment, the first electrical contact 206 and the second electrical contact
208 may be on the first side of the OLED 200 or on the second side of the OLED 200.
[0052] Those skilled in the art will appreciate that even though the number of first electrical
contacts 206 and the number of second electrical contacts 208 shown in FIG. 2 is one each, the
number can be more than one without deviating from the scope of the invention. For example, a
scenario when the number of first electrical contacts 206 and the number of second electrical
contacts 208 is two each has been illustrated in FIG. 5.
[0053] The recess 204 of the OLED 200 is also shown to include the notch 210. The notch
210 is provided so as to enable placement of the OLED 200 in a predetermined orientation, or a
unique way, and to ensure that the correct electrode layer is placed in contact with the correct
external electrical contact. Further details relating to size and shape of different elements of the
OLED 200 will be explained in association with FIG. 4.

[0054] Moving on, there is shown in FIG. 3a, an illustration of a cross section of the OLED
200 of FIG. 2 across the line A-A, in accordance with an embodiment of the present invention.
The section of OLED 200 across the line A-A is shown to have a stack of layers including the
substrate 202, an internal light extraction layer 304, a first electrode layer 306, one or more
organic layers 308, 310 and 312, a second electrode layer 314 and a cover substrate 316. The
cross section also includes the first electrical contact 206.
[0055] The stacks of layers of the OLED 200 including the substrate 202, the internal light
extraction layer 304, the first electrode layer 306, the one or more organic layers 308, 310 and
312, the second electrode layer 314 and the cover substrate 316 are similar in characteristic to the
substrate 102, the internal light extraction layer 104, the first electrode layer 106, the one or more
organic layers 108, 110 and 112, the second electrode layer 114 and the cover substrate 116 of
the OLED 100 described in FIG. 1.
[0056] Further, the first electrode layer 306 can be implemented as a cathode and is shown
to be in connection with the first electrical contact 206 as illustrated in the figure. Similarly,
FIG. 3b illustrates a cross section of the OLED 200 of FIG. 2 across the line B-B, in accordance
with an embodiment of the present invention.
[0057] The section of the OLED 200 across the line B-B is shown to have a stack of layers
including the substrate 202, the internal light extraction layer 304, the first electrode layer 306,
the one or more organic layers 308, 310 and 312, the second electrode layer 314 and the cover
substrate 316. The cross section also includes the second electrical contact 208 in contact with
the second electrode layer 314 which can be implemented as an anode.
[0058] The connection of the first electrode layer and the second electrode layer with the
first electrical contact and the second electrical contact respectively enables application of

electrical current across the organic layers 308, 310 and 312 and enables the OLED 200 to emit light.
[0059] Moving on, there is illustrated in FIG, 4 the OLED 200 and its correspondence to a conventional lighting device fixture 400. The conventional lighting device fixture 400 shown is a classic light bulb socket used in association with a conventional incandescent or a fluorescent light bulb. In an embodiment, the conventional lighting device fixture 400 can be an Edison Screw 27 size (E27) socket. Other examples of the conventional lighting device fixture 400 include, but are not limited to, El 1, El2, El4, El7 and E26 sockets. [0060] The conventional lighting device fixture 400 is shown to include a conventional spiral ridge shaped wiring circuitry 402 that includes a voltage/current adopter, an OLED positioning protrusion 404, a conventional ceramic or plastic holder 406 and electrical contacts 408 and 410. For the purpose of the description, the conventional lighting device fixture 400 has been shown to include only those elements that are pertinent for the description of the invention. However, it should be understood that the invention is not limited to only the elements listed above.
[0061] The recess 204 of the OLED 200 is of a size such that it corresponds and conforms to dimensions of the conventional holder 406 and is sufficiently sized to allow passing of the conventional holder 406. For example, in real life applications, if the conventional lighting device fixture 400 is an E27 socket where the conventional holder 406 has a diameter Dl of approximately 14.5 mm, then the recess 204 of the OLED 200 will have a diameter D2 of approximately 15 mm and the OLED 200 itself will have a diameter of approximately 120 mm. [0062] Further, the notch 210 of the OLED 200 is in conformance with the OLED positioning protrusion 404 and enables proper positioning and alignment of the OLED 200 in the

conventional lighting device fixture 400. In the figure the notch 210 and the OLED positioning protrusion 404 are shown to be triangular in shape. However, those skilled in the art will appreciate that they can be of any other suitable shape like round or polygonal, without deviating from the scope of the invention. In other embodiments, more notches 210 may be placed without deviating from the scope of the invention. An illustration of such an embodiment, where the lighting device fixture and the OLED have three protrusions 502, has been provided in Figs. 5a and 5b. Also, the notch 210 ensures proper coupling of the electrical contacts of the OLED 200 and the metal contacts of the conventional lighting device fixture 400.
[0063] In some embodiments of the invention, the OLED 200 can also include positioning pins around the periphery of the recess 204 for better coupling and attachment with the conventional lighting device fixture 400. Also, in some embodiments, the OLED 200 can also include a protection and possibly even a clamping cap [protection cap 602 illustrated in association with Figs. 6a and 6b] positioned above the OLED 200 and clamped with the conventional lighting device fixture 400 to ensure protection of the OLED from ambient environment, thereby providing a standalone device that can be readily installed in the conventional lighting device fixture 400. Such a setup, as the one provided by the present invention, enables a user to purchase a holder and easily change the OLED disc. [0064] Various embodiments, as described above, provide an OLED for retrofitting in conventional lighting device fixtures, which has several advantages. One of the several advantages of some embodiments of this device is that it is capable of replacing previously used conventional lighting devices like incandescent or fluorescent light bulbs. Further, the planar charateristics of the OLED remains, without bulky side connect and can be very conveniently

installed in conventional lighting device fixtures. Another advantage of the OLED of the present invention is that it can be used as both a top emitting and a bottom emitting OLED. [0065] While the invention has been disclosed in connection with the preferred embodiments shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present invention is not to be limited by the foregoing examples, but is to be understood in the broadest sense allowable by law. [0066] All documents referenced herein are hereby incorporated by reference.

Claims
1. An organic light emitting device comprising:
a substrate having a first side, a second side and a recess;
a first electrode layer provided on said first side of said substrate;
one or more light emitting layers provided on said first electrode layer;
a second electrode layer provided on said one or more light emitting layers;
one or more first electrical contacts and one or more second electrical contacts arranged alternately around a periphery of said recess, whereby forming an annular arrangement proximal to said periphery, further wherein said one or more first electrical contacts are in contact with said first electrode layer and said one or more second electrical contacts are in contact with said second electrode layer.
2. The organic light emitting device according to claim I, wherein a shape of said substrate is selected from one of a circle, an ellipse, and a polygon having more than four sides.
3. The organic light emitting device according to claim 1 further comprising one or more notches positioned on said periphery of said recess, said one or more notches being adapted for aligning said organic light emitting device with a light bulb socket including at least one of a current and a voltage adapter.
4. The organic light emitting device according to claim 1, wherein said periphery of said recess includes one or more positioning notches to attach said organic light emitting device to a light-bulb socket with adaptor and positioning protrusions.

5. An organic light emitting device according to claim 1, wherein said recess is circular in shape and a centre of said recess is equidistant from a periphery of said substrate.
6. An organic light emitting device according to claim 1, wherein said one or more first electrical contacts and said one or more second electrical contacts are on at least one of said first side of said substrate or said second side of said substrate.
7. The organic light emitting device according to claim 1, wherein said organic light emitting device is configured to be removably coupled to a light-bulb socket.
8. The organic light emitting device according to claim 1, wherein said recess has a diameter of 15 mm and said substrate has a circular shape with a diameter of 120 mm.