Ultra-thin OLED lighting panel

Abstract

A flexible lighting panel, comprising: a light emitting unit with electrical contact pads on a flexible substrate; a flat flexible printed circuit board with a bendable extension tab, wherein the circuit board is located on a side of the light emitting unit opposite to the substrate; an area of ​​the circuit board not including the extension tab is equal to or larger than the emission area of ​​the light emitting unit and overlaps with it; and the circuit board has at least two flat electrical connectors, which are in electrical contact with the contact pads of the light emitting unit; the flat electrical connectors extend along the extension tab of the circuit board for connection to a power source. The light emitting unit may be an OLED. The extension tab may be bent so that the flat electrical connection becomes accessible in different directions. The panel may be ultra-thin.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 615,135, filed January 9, 2018. Reference is also made to commonly filed and commonly assigned (PCT International Application No. PCT / EP2019 / 050399), entitled “Thin OLED Lighting Module”. Background Art

[0003] OLED lighting panels, which rely on OLED technology to produce light, offer many advantages for general lighting purposes. They are efficient in terms of light output for the power consumed. They are low voltage, which helps avoid potential electric shock, are less prone to sparks in potentially explosive environments, and they reduce the load on supporting electrical systems. The spectrum of the emitted light can be changed using appropriate internal design. They produce little or no UV or IR light. They are instant-on; that is, they emit light as soon as power is supplied. OLED light sources are naturally flat, surface light sources. They offer several advantages over LED lighting panels. They can be made thinner (e.g., less than 1 mm thick), and they generate less heat under normal operating conditions. However, OLED life can be an issue. Both LED and OLED lighting panels can be manufactured on flexible or curved substrates, although OLEDs are preferred for these types of applications. In summary, OLED lighting panels can be used as lighting panels. They are efficient, low voltage, cool to the touch, and thin. Luminaires (complete units having a light source (i.e., lamp) and a supporting component (i.e., lamp holder) that provide light and illumination) can be designed to utilize OLED lighting panels.

[0004] In the lighting industry, luminaire design is often critical. In addition to solving general or specific lighting needs, luminaires become part of the built environment. It is highly desirable to design luminaires that take advantage of some of the unique physical properties of OLEDs compared to other light sources, such as LEDs. In particular, OLED lighting panels can be thinner and more flexible than LED lighting panels.

[0005] Generally speaking, an OLED panel used in a luminaire will have at least three parts: a substrate or support, an OLED light emitting unit, and electrical connections to provide power from an external source to the internal OLED electrodes. The OLED light emitting unit has at least one organic electroluminescent layer between two electrodes on the substrate, and will be encapsulated to protect the electroluminescent layer(s) from air and / or water.

[0006] Typically, an OLED panel will have an emissive region surrounded by a non-emissive border. Electrode contact pads connected to the internal electrodes are typically located on the same side of the substrate as the electroluminescent layer, in these non-emissive border regions. However, in order to provide mechanical support for the OLED light emitting unit and to supply power from an external source, this often results in a thicker panel than is desired for design purposes.

[0007] OLED light emitting units can be fabricated on rigid or flexible substrates. While both can be very thin, flexible substrates are advantageous because they can be used in curved or bent designs and can be used in rigid (flat or curved) applications when further supported by a non-flexible housing or mount.

[0008] However, some panel applications require that the electrical connection is not on the same surface of the substrate as the OLED light emitting unit. For example, some applications may require that the electrical connection be made from the edge of the device rather than from one of the planes. Other applications may require that the electrical connection be made from the side of the OLED unit opposite the substrate rather than from the same side as the OLED unit. These types of applications will result in an increase in the thickness of the panel. In addition, it also requires a more complex manufacturing process because different designs must use different manufacturing processes.

[0009] It is desirable to design a flexible OLED lighting panel that is as thin as possible and allows electrical connections to be made to a power source in different configurations. Such a design would be aesthetically appealing in many applications and could be easily adapted to a particular use.

[0010] JP06-223972 describes an OLED lighting panel having electrode leads on the emitting side that bend over the edge of the panel to make contact with pads on the back side of the device. However, such leads need to be thick in order to bend and without any support, and are prone to displacement and short circuiting when the panel is assembled into a bracket.

[0011] US6565231 and US6787990 describe the use of OLEDs in housings with extended tabs having electrical connectors that fit into sockets for mechanical substrates and electrical connections. The tabs are not flexible. US9647052 describes an OLED with a hinge-allowing section with embedded wire traces where the substrate folds back onto itself. Similar OLEDs are described in EP3231013, EP3231014, EP3231015, and EP3235001.

[0012] US9035290 describes an OLED with a flexible printed circuit board attached to a control circuit at one end and folded over and around the edge of a substrate. EP3226321 describes the use of a flexible printed circuit board in an OLED. US8492969 and US9148497 describe the use of a flexible printed circuit board to connect a control circuit chip located on the back of a substrate to a light emitting element. All of these references relate to OLED displays. Summary of the invention

[0013] A flexible lighting panel having an emitting surface and an opposite surface, comprising: a light emitting unit, which includes at least one electroluminescent layer between a first electrode and a second electrode on a flexible substrate to form an emitting area, the light emitting unit having at least two electrical contact pads, each of which is individually in contact with the first electrode or the second electrode and is located in a non-emitting area of ​​the substrate; at least one flat flexible printed circuit board, which has at least one bendable extension tab, wherein the circuit board is located on the side of the light emitting unit opposite to the substrate; the area of ​​the circuit board that does not include the extension tab is equal to or larger than the emitting area of ​​the light emitting unit and overlaps with it; and the circuit board has at least two flat electrical connectors, which are on the surface of the circuit board facing the light emitting unit and are in electrical contact with the contact pads of the light emitting unit; the flat electrical connector extends along the extension tab of the circuit board for connection to a power source.

[0014] The lighting panel has three modes of operation: a first mode in which the bendable extension tab is not bent so that power can be supplied to a flat electrical connector on the emitting face; a second mode in which the extension tab is partially bent and oriented so that the flat electrical connector can be accessed along the edge of the panel; and a third mode in which the extension tab is fully folded back onto the circuit board so that the flat electrical connector can be accessed along the opposite face of the panel and the edge of the panel. The bendable extension tab can be smaller in width than the edge of the circuit board.

[0015] The flat electrical connectors on the bendable extension tab can be patterned so that a single portion of one of the flat electrical connectors is located between two interconnection portions of the other flat electrical connector. In particular, the extension tab is positioned along the edge of the panel so that the center of the space between the single portion of one flat connector and one of the interconnection portions of the other flat connector is positioned along the midpoint of the edge of the panel.

[0016] The flat electrical connector may be at least 65% or more of the area of ​​the circuit board. In addition, the circuit board is larger in area than the substrate so that a portion of the circuit board overhangs an outer edge of the substrate. The circuit board may include a plastic or polymer carrier having a total thickness not exceeding 0.015 mm.

[0017] There may be a flexible light management unit on the emitting face of the lighting panel that completely covers the emitting area and is equal to or larger in area than the emitting area. In some embodiments, the flexible light management unit is larger in area than the substrate so that a portion of the light management unit overhangs an outer edge of the substrate.

[0018] If both the light management unit and the circuit board have portions that overhang the substrate, the overhanging portions may be joined together by adhesive or mechanical force.

[0019] Ideally, the light emitting unit is an OLED, the substrate is transparent, and light is emitted through the substrate.

[0020] The above features provide an ultra-thin and flexible lighting panel with three electrical connection modes depending on the configuration, which is easy to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A is a top view of an emitting surface of one embodiment of a lighting panel. Figure 1B is a view of the non-emissive side of the same lighting panel.

[0022] Figure 2A yes Figure 1A Cross-sectional view of the lighting panel of the illustrated embodiment with the extended tab in an unbent configuration. Figure 2B is a front view of the extended tab.

[0023] Figure 3A is a cross-sectional view of a lighting panel, wherein the extension tab is bent at a right angle. Figure 3B is an end view of the bent extension tab.

[0024] Figure 4A is a cross-sectional view of a lighting panel with the extension tab folded back onto the circuit board. Figure 4B is an end view of the extended tab. Figure 4C It is a top view of the back side of the panel.

[0025] Figure 5A is a cross-sectional view showing the portion of the light management unit and circuit board that extends beyond the outer edge of the light emitting unit / substrate. Figure 5B The use of an adhesive is shown. Figure 5C The attachment mechanism is shown.

[0026] Figure 6 is a top view of a light emitting unit on a flexible substrate.

[0027] Fig. 7A is a top view of a flexible printed circuit board showing one layout of flat electrical connectors. Figure 7B yes Fig. 7AA top view of the extended tab area is shown, showing the arrangement of the flat connector.

[0028] Figure 8 is a top view of another layout of a flat electrical connector.

[0029] Fig. 9 is a top view of another layout of a flat electrical connector.

[0030] Fig.10 An arrangement of flat electrical connectors is shown, wherein one flat electrical connector crosses over another flat electrical connector without electrical contact.

[0031] Because the structures involved are very small, the drawings are merely illustrative and not drawn to scale. DETAILED DESCRIPTION

[0032] In the following, the exemplary panel structures are all shown as being rectangular in shape and length, and therefore, reference is made to the length and width. However, the panel is not limited to any particular shape, and therefore may be square, circular, oval, triangular, or irregular. In any case, the panel structure will all have outer edges, and therefore for shapes other than square or rectangular, corresponding dimensions (e.g., radius for circular panels) should be applied. Rectangular or square panels are preferred. In addition, although the examples relate to specific examples using OLED as light emitting units, any type of light emitting unit containing organic materials is generally useful. "Flat" means that the thickness dimension is much smaller than the length and / or width dimension (usually less than 1:100). Note that "flat" refers only to the ratio of thickness to the other two dimensions; therefore, a "flat" plane may have a bent or curved shape. "Ultra-thin" means that the thickness of the panel does not exceed 0.7 mm, and is desirably 0.5 mm or less.

[0033] Figure 1A and 1B FIG. 1 is a top view of an embodiment of a lighting panel of the present invention. Figure 1AThe emitting surface of the lighting panel 100 is shown, wherein the front surface is an optional flexible light management unit 2. Below the light management unit 2 is a flexible light emitting unit / substrate 4, also referred to as an OLED unit / substrate 4 in some embodiments. The light emitting unit is arranged on the substrate so that light is transmitted through the light management unit 2. Below 4 is a flat flexible printed circuit board 6, which has a bendable extension tab 8, and there are two flat electrical connectors 10, 12 on the bendable extension tab 8. The flat electrical connectors 10, 12 are in electrical contact with the first and second electrodes of the light emitting unit. Two optional electrical contact pads 11 are also shown; one is in electrical contact with 10, and the other is in electrical contact with 12. Figure IB shows the non-emitting surface of the panel 100. An optional reinforcement member 13 is attached to the back side of the extension tab 8. At Figure 1A and 1B In FIG. 8 , the extended tab 8 is shown in an unbent configuration, wherein the external electrical connectors 10 , 12 face in the same direction as the light emission.

[0034] Figure 2A Shown along Figure 1A A cross-sectional view of the lighting panel 100 is shown along line 2A. 2 is a flexible light management unit. Figure 1A The light emitting unit / substrate 4 comprises a flexible transparent substrate 41, an OLED light emitting unit 42 (including a first electrode 46, (one or more) organic layers 47, a second electrode 48 and an encapsulation 43) and two contact pads 44 and 45 of opposite polarity electrically connected to the first and second electrodes of the OLED light emitting unit 42. The light emitting unit 42 is arranged so that it transmits light through the substrate 41 and through the light management unit 2. In this embodiment, the light emitting unit 42 is located on the face of the substrate 41 opposite to the light management unit 2. The contact pads 44 and 45 are located outside the encapsulation 43 and on the same face of the substrate 41 as the light emitting unit 42 and are located in the non-emitting area of ​​the substrate. On the light emitting unit / substrate 4 is an optional adhesive layer 7, which attaches the upper circuit board 6 to the lower light emitting unit / substrate 4. The flexible printed circuit board 6 has an extension tab 8 with flat electrical connectors 10, 12. Each of these flat connectors 10, 12 on the circuit board 6 is connected to one of the contact pads 44 and 45 via electrical connectors 91 and 92, respectively. Flat electrical connectors 10 and 12 are located on the face of the circuit board 6 facing the light emitting unit / substrate 4 and facing the direction of light emission (in this embodiment). There are reinforcements 13 on the back side of the extending tabs 8 of the circuit board 6. The contact pads 11 are not shown. Figure 2B A front side view of the unbent extension tab 8 of the light emitting lighting unit 100 is shown. In this embodiment, the flat electrical connector 10 is connected via 91 to one of the OLED contact pads and the flat electrical connector 12 (hidden in this view) is connected via 92 to the other contact pad.

[0035] Figure 3A 2 is a cross-sectional view of a lighting panel 200, which is similar to the lighting panel 100 except that the extension tab 28 is bent 90 degrees. The flat electrical contacts 20, 22 on the surface of the extension tab are also bent. The bending of the extension tab 28 allows electrical contact from the power supply to the flat electrical contacts 20, 22 in a direction perpendicular to the light emission direction (i.e., from the edge of the lighting panel 200). Figure 3B 26 is a side view of the bent and extended tab 28 of the lighting panel 200. 27 is a side edge of the circuit board. The contact pad 11 is not shown.

[0036] Figure 4A is a cross-sectional view of an OLED lighting panel 300 that is similar to lighting panel 100 except that the extension tab 38 is bent completely back so that the back side of the extension tab 38 (i.e., the side opposite the flat electrical connector) is located along the back side of the circuit board 36. The folding back on itself allows electrical contact to be made from a power source to the flat electrical contacts 30, 32 in a direction perpendicular to the light emission direction (edge ​​of the lighting panel 300) or in a direction opposite to the light emission direction (non-emitting back side of the panel 300). Figure 4B 36 is a side view of the front side of the folded-back extension tab 38 of the OLED lighting panel 300. 36 is a side edge of the circuit board. Figure 4C is a top view of the back side of the panel 300 showing the folded back extension tab 38. The contact pads 11 or reinforcement 13 are not shown.

[0037] The embodiment shown in Figures 1-4 has a light management unit 2 on the emitting side of the device that is larger in length and width dimensions than the underlying OLED unit / substrate 4. On the non-emitting side of the panel there is a circuit board 6 that is also larger in length and width dimensions, and thus in area, than the upper OLED unit / substrate 4. This Figure 5A 4. Thus, there are overhanging portions 21 of the light management unit 2 and portions 61 of the circuit board 6 that extend beyond the outer edges of the OLED unit / substrate 4 and are not in direct contact with the OLED unit / substrate 4. Note that since both the light management unit 2 and the circuit board 6 are flexible, these layers can naturally come together anywhere they are not separated by the OLED unit / substrate 4. These overhanging portions can be as Figure 5B The extensions 21 and 61 help protect the edges of the OLED unit / substrate 4. In addition, these extensions can be used to attach the panel to a lighting module or luminaire without having to directly attach the OLED unit / substrate, such as Figure 5Cas shown. This allows for a very thin attachment member 16, since the OLED cell / substrate 4 does not have to be fitted under or in the attachment member 16. This also helps prevent the OLED panel from warping due to thermal expansion during operation, since the OLED cell / substrate 4 is not directly attached to the attachment member 16, but is only attached via an extension of the layer above the OLED cell / substrate 4 (61) and an extension of the layer below (21). This attachment allows for some freedom of movement of the OLED cell / substrate 4, but still firmly secures the outer edges of the panel. In addition, the presence of the light management unit 2 on the front (emitting) face of the panel and the circuit board 6 on the rear (non-emitting) face of the panel increases safety in the event of a breakage of the substrate (which may include a material such as glass), and increases flame retardancy. The overlapping portion may also provide protection for the edges of the OLED substrate. The overhanging portions 21 and 61 may also be joined together by mechanical means (e.g. a clamp) or by pressure applied by the attachment member 16.

[0038] However, other applications may not require these overlapping portions of the light management unit or even the light management unit itself. The presence of the light management unit is optional. In cases where a light management unit is used but does not need to have portions extending from the edge of the OLED unit / substrate, the light management unit only needs to be large enough to completely cover the emitting portion of the OLED unit. Therefore, the light management unit should be equal to or larger in area than the emitting area, but may be equal to, smaller than, or larger in area than the OLED substrate. It is expected that, when present, the light management unit is equal to or larger in area than the OLED substrate and the body of the circuit board.

[0039] Figure 6 Further details of the flexible light emitting unit / substrate 4 are shown. Figure 6 The view in is of the non-emissive surface of the light emitting unit / substrate 4. The light emitting unit 42 is deposited on a flexible substrate 41 having an outer edge 46. The length and width of the light emitting unit 42 are both smaller than the length and width of the flexible substrate 41 so that it is completely located within the outer edge 46. The light emitted from the light emitting unit passes through the transparent flexible substrate 41. The area outside the light emitting unit 42 is non-emissive. In this embodiment, the non-emissive area completely surrounds the emitting area on all sides. Contact pads 44 and 45 for the light emitting unit are located in this area of ​​the non-emissive surface. In Figure 6In an embodiment, there are two contact pads (44) and two contact pads (45), the two contact pads (44) are connected to one of the internal electrodes of the light emitting unit on the two long edges of the light emitting unit and extend partially along the short edges, and the two contact pads (45) are connected to the other internal electrode on the two short edges. The two types of contact pads are separated from each other to prevent short circuits. However, the layout and number of contact pads can be selected as needed and are not limited to this orientation. For example, there may be one contact pad along one edge of the light emitting unit and another contact pad on the other three edges, or there may be two contact pads of opposite polarity along each of the four edges on the light emitting unit, wherein each contact pad extends only along half the length of the edge.

[0040] Fig. 7A Further details of the flat flexible printed circuit board 6 are shown, showing one embodiment for positioning the flat electrical connectors 10 and 12 . Fig. 7A The view is what the board will eventually face. Figure 6 The flat electrical connector 12 covers most of the surface of the circuit board 6 and is positioned (when assembled to the side of the light emitting unit / substrate 4 shown in FIG. Figure 6 4 shown as the non-emitting surface of the substrate 41) so that it can make electrical contact with the two contact pads 45 on the short end of the substrate 41, but does not overlap or make electrical contact with the other two contact pads 44 on the long end of the substrate 41. The flat electrical connector 12 also has a narrow portion extending along the extension tab 8. The flat electrical connector 10 extends along the side of the other connector 12 and is positioned (when assembled) so that it can make electrical contact with the two contact pads 44 on the long end of the substrate 41, but does not overlap or make electrical contact with the other two contact pads 45 on the short end of the substrate 41. The flat electrical connector 10 also has two interconnecting portions that extend along the outer edge of the extension tab 8, which surround but do not contact the extension of the connector 12.

[0041] Figure 7B Shown from Fig. 7A 1. An enlarged view of a section of the extended tab 8 of the circuit board 6. Because this connector layout requires the connector 10 to extend along both long edges of the circuit board 6, there is an interconnect bridge 18 that allows power to flow to both edges. This allows external electrical connections to be made to the connector 10 on only one side of the tab 8 and avoids the need to span one connector across another. In order to center the external connector on the panel, the midpoint of the panel (indicated by the dotted line) should fall between one side of the connector 10 and the connector 12. In order to achieve this, it is necessary to have the extended tab 8 not centered on the edge of the panel, but offset from the centerline of the panel (indicated by the dotted line) (distance X>distance Y).

[0042] Figure 8 Shows that different from Fig. 7A Another embodiment for positioning flat electrical connectors 10 and 12 on a circuit board 6 is shown. In this embodiment, the flat electrical connector 12 is a long strip that makes electrical contact with both parts of the contact pad 45 (when connected with the flat electrical connector 12). Figure 8 The flat electrical connector 10 only covers a portion of the two contact pads 44 and does not extend along the long edge of the circuit board 6 .

[0043] Fig. 9 1 shows another embodiment of the layout of the flat electrical connectors 10, 12 on the circuit board 6. In this embodiment, the electrical connector 10 is a single strip extending parallel to the outer edge of the circuit board 6, while the electrical connector 12 fills most of the internal space within the electrical connector 10. In this embodiment, the extension tab 8 can be centrally located at the midpoint of the edge of the circuit board 6, as shown by the dotted line (distance X = distance Y). When compared with Figure 6 When the illustrated contact pad layout is placed face to face, the flat connector 10 will contact two contact pads 44 and the flat connector 12 will contact two contact pads 45 .

[0044] In some embodiments, it may be desirable to cross one of the flat electrical connectors with another without forming electrical contact between them. In these cases, it may be desirable to use an electrical insulating layer between them to prevent short circuits.

[0045] Fig.10 1 shows an example where the flat electrical connectors 10, 12 cross each other without contacting each other. In this embodiment, the flat connector 12 extends from the extension tab 8 to the inside of the circuit board 6 to contact the pad 45 (when in contact with the pad 45). Figure 6 The flat connector 10 (which still has to contact the pads 44 along the long edges of the substrate 41) has a bridge area 24 passing over the flat electrical connector 12. In the bridge area 24, there is no contact between the flat electrical connectors 10 and 12, which can be separated by an insulating layer (not shown). In this embodiment, it is only necessary to have a single section of each flat connector 10 and 12 on the extension tab 8, so the extension tab 8 can be centered at the midpoint of the edge of the circuit board 6, as shown by the dotted line (distance X=distance Y).

[0046] In all the above embodiments, the flat electrical connectors 10 and 12 should never be in direct electrical contact with each other. When the non-emitting face of the substrate 41 and the face of the circuit board 6 having the electrical connectors 10 and 12 are assembled face to face, the electrical contact between the flat electrical connectors 10 and 12 of the circuit board 6 and the contact pads 44 and 45 on the substrate 41 can be direct. Alternatively, a conductive glue or adhesive, an ACF (anisotropic conductive film) of appropriate size and shape, or a conductive adhesive such as Figure 2A Additional electrical connectors shown at 91 and 92 may be used to make electrical contact therebetween.

[0047] It is desirable that the flat electrical connector 12 and the contact pad 45 are connected to the cathode of the light emitting unit. The flat electrical connector 10 and the contact pad 44 are desirably connected to the anode of the light emitting unit. Although these figures show a specific layout of the flat electrical connector on the circuit board and the contact pad on the substrate for illustration, the layout can be appropriately adjusted.

[0048] The lighting panel is suitable for general lighting applications. It can be appropriately modified for specific applications. For example, it can be equipped with a lens to focus the emitted light in order to act as a highlight, or it can be equipped with a filter to adjust the color temperature of the emitted light. It can be used directly as part of a specific luminaire design or can be used as a light source in a lighting module that can be used interchangeably between different luminaire designs.

[0049] The lighting panel has at least one light emitting face or surface. The opposite face or surface of the panel can be non-emitting, so that the panel has a single-sided emission. The opposite face or surface can also be light emitting, so that the panel has a double-sided emission. In this case, the circuit board should be transparent and the flat electrical connector as small as possible. If desired, the lighting panel can be transparent or translucent. The (one or more) light emitting surfaces can have an emitting area and a non-emitting area. Desirably, the non-emitting area will surround a single emitting area and have a total non-emitting area that is smaller than the emitting area. Most desirably, the panel has a single-sided emission, wherein the non-emitting area surrounding the emitting area is as small as possible.

[0050] Flexible light management units serve a variety of purposes and may be constructed of multiple layers. Its primary purpose is to increase the amount of light scattering of light transmitted through the substrate, thereby improving the light distribution from the device and increasing overall efficiency. Typically, the flexible light management unit will have a light scattering medium located on the surface or within the flexible polymer or glass substrate, or the flexible substrate will contain physical structures that cause light scattering (e.g., bumps or protrusions of various shapes). In some cases, the flexible light management unit may be part of the same flexible substrate as the light emitting / substrate unit. In other cases, it may be a separate unit in the form of a film that is applied to the light emitting surface of the light emitting unit / substrate using an optically clear adhesive. In addition to its light management function, it will also help protect the surface of the device from damage. In embodiments where the light management unit is larger in area than the substrate so that a portion overhangs the substrate, the overhanging portion may be used to attach the device to a mount or surface. In addition, the overhanging portion may help protect the edges of the substrate, particularly a flexible glass substrate.

[0051] Light emitting unit / substrate refers to a complete light emitting unit located on a substrate. A complete light emitting unit will have a first electrode, (one or more) electroluminescent layers, a second electrode, all of which are completely covered by an encapsulation portion to prevent contact with air and water. Desirably, the light emitting unit is an OLED unit, wherein the electroluminescent layer is organic.

[0052] The substrate is flexible and can be made of flexible glass, metal or polymer material. Flexible glass is the most desirable. Generally speaking, it will be flat with uniform thickness. In some cases, it may be necessary to provide features in the substrate to increase flexibility. If the substrate is flexible glass, the glass edge can be heat treated to remove any surface defects. Defects in the glass edge (such as notches or defects) may be the source or starting point for the glass to break under stress. Heat treatment can prevent this by removing any defects, thereby increasing effective bendability without breaking. For bottom-emitting devices, the substrate should be transparent. For top-emitting devices, the substrate can be opaque or transparent as required (allowing double-sided emission). The top surface of the substrate is the surface facing the light-emitting unit. Since the substrate will be part of the entire packaging portion of the device, it should be sufficiently impermeable to air and water so that the device will have the desired life. The substrate can have various types of coating layers (subbing layers) or barrier layers, which can be patterned or unpatterned and can be on the top or bottom surface.

[0053] In the light emitting unit, there is a first electrode that covers the top surface of the substrate and desirably completely covers the top surface of the substrate. The first electrode can be an anode or a cathode, and can be transparent, opaque or translucent. Desirably, the first electrode is a transparent anode and the device is a bottom emitter. The transparent first electrode should transmit as much light as possible, preferably with a transmittance of at least 70%, or more desirably at least 80%. However, in some applications (i.e., microcavity devices), the transparent first electrode may be only translucent and partially reflective. Although the first transparent electrode can be made of any conductive material, metal oxides such as ITO or AZO or metal thin layers such as Ag are preferred. In some cases, an auxiliary electrode may be present to help distribute the charge more evenly over the entire plane of the transparent electrode.

[0054] For embodiments in which the light emitting unit is an OLED, an organic layer for light emission will be deposited and will be in contact with the first electrode. At least one organic layer will be electroluminescent. There may be more than one layer, and some layers may not be light emitting. Formulations and layers suitable for OLED type light emission are well known and can be used as needed. The organic layer may be a small molecule or a polymer. The organic layer may be deposited by any known method, including vapor deposition, solution coating, inkjet technology, spraying, etc. The organic layer may be patterned. Inorganic electroluminescent materials such as quantum dots may also be used for light emission. Because such a formulation also includes organic materials, the use of inorganic electroluminescent materials may be considered as OLED for the purposes of the present invention.

[0055] On the organic layer, there is a second electrode. It can be an anode or a cathode; preferably a cathode. The second electrode can be transparent or opaque, preferably opaque. If transparent, it is desirably composed of a conductive transparent metal oxide such as ITO or a thin layer of a metal such as Ag. If opaque, it is desirably composed of a thicker layer of a metal or metal alloy, such as Al, Ag, Mg / Al, Mg / Ag, etc. The second electrode can be deposited by any known technique.

[0056] Above the second electrode, there may optionally be a protective organic layer, a protective inorganic layer, or a combination of both. This is to prevent damage to the second electrode and the underlying organic layer during encapsulation.

[0057] The light emitting unit is fully encapsulated. The encapsulation on one surface is provided by the substrate. The sides and top of the light emitting unit may be encapsulated by a flexible impermeable cover attached to the substrate to seal the unit. Most desirably, the encapsulation of the sides and top of the unit is provided by a thin film encapsulation. The thin film encapsulation typically includes a plurality (e.g., 3 or more) alternating layers of inorganic and organic materials. Alternatively, the thin film encapsulation may include an adhesive layer with embedded hygroscopic getter particles having an impermeable barrier layer or film, such as a thin metal foil or plastic barrier film. There are conductive extensions of the first and second electrodes, which will extend through the encapsulation and form contact pads for external electrical connections. Since the substrate is part of the encapsulation, it may be necessary to add additional thin film encapsulation, such as a barrier layer, on either side of the substrate to provide additional protection. The additional barrier layer(s) may be the same as the barrier layer applied to the light emitting unit, or made of a different material.

[0058] On the light emitting unit / substrate, there may be an optional adhesive material and / or a protective layer to fix the light emitting unit / substrate to the circuit board above. These materials should be flexible. Examples of suitable adhesive materials can be double-sided tape or liquid adhesives, which can be applied by spraying, brushing, rolling, laminating or similar methods. Metal foil may also be present to help act as a heat sink and prevent damage to the OLED unit during manufacturing. Inorganic or polymer layers may also be used as protective layers. Metal foil or other protective layers may be present between adhesive layers. If the protective layers are conductive, they must be arranged not to contact the contact pads of the light emitting unit or the flat electrical connectors of the circuit board or any connector between the two. If the panel has double-sided emission, the adhesive and / or protective layer should be translucent or transparent.

[0059] On the light emitting unit / substrate and optional adhesive material and / or protective layer, there is a flexible printed circuit board. Desirably, the body of the circuit board (excluding the tab) has an area that is the same as or larger than the emission area of ​​the light emitting unit, even if it is located on the non-emitting surface of the substrate. In this way, the circuit board can provide protection to prevent damage to the unit below and act as a heat sink. In addition, the circuit board (excluding the tab) can completely overlap with the substrate and can have the same or larger area as the substrate. In an embodiment where the circuit board (excluding the tab) is larger than the substrate in area so that there is a portion (except the tab) that overhangs the substrate, the overhanging portion can be used to attach the device to a mounting member or surface. Moreover, the overhanging edge can protect the edge of the substrate. If the panel has double-sided emission, the circuit board should be translucent or transparent. In an embodiment where the circuit board is smaller than the emission area of ​​the OLED in area, the circuit board can be located anywhere on the surface or side of the OLED substrate. It can also form a frame surrounding the outer edge of the OLED substrate and can overhang or not overhang the OLED substrate.

[0060] The substrate or carrier of the flexible printed circuit board is made of a non-conductive plastic or polymer material. It can be made of two or more layers, and these layers can be made of different materials. At least, there are at least two flat electrical connectors on one surface of the circuit board, which extend along the extension tabs. Other features related to electrical control (such as transistors) or power (such as resistors) may be present on either surface of the circuit board or on the extension tabs.

[0061] One advantage of positioning the flat electrical connector on a bendable or foldable flexible extension tab is that the flat wire can be made very thin and still bend without cracking or breaking. In addition, the tab can be manipulated more easily and more durable than a free wire. Finally, the tab holds the flat electrical connector in a fixed position, which makes external electrical attachment easier and more reliable because the connector will not tend to move out of position during assembly or handling. In order to facilitate external electrical connection, it is desirable that the two flat electrical connectors on the tab should each have an area of ​​at least 5 mm by 5 mm. Alternatively, additional conductive contacts or pads (i.e. Figure 1A The pads 11 in the FIG. 10A can be electrically connected to the flat electrical connector. The use of such pads (which can be thicker than the flat electrical connector) increases the physical durability when connected to an external power source. For example, they can be made of copper coated with SnAg and can be connected to the flat electrical connector by solder, ACF or conductive adhesive.

[0062] The flat electrical connections on the flexible printed circuit board are made of conductive metal (e.g., Al, Cu, Sn) and are thin. They should be flexible enough to be able to bend with the extension tabs without breaking. The surface of the circuit board with the flat electrical connector faces the adhesive material and / or the protective layer (if present) and the OLED unit. Since in some embodiments, the flat electrical connector can be bent with the extension tabs, the flat electrical connector can include stress relief features that allow bending without breaking or cracking. There can be an adhesive between the flat electrical connector and the circuit board. In addition, the flat connector can be located in a channel or hollowed-out space on the polymer substrate of the circuit board so that the surface of the circuit board is flat.

[0063] Desirably, the maximum total thickness of the circuit board should be 0.2 mm or less; the thickness of the polymer substrate should be 0.1 mm or less; the thickness of the flat electrical connector should be 0.09 mm or less, and the thickness of any adhesive between the flat connector and the plastic substrate should be 0.01 mm or less.

[0064] One advantage of having flat electrical connectors covering most of the surface of the circuit board is that, since they are metal, they can also be used as heat sinks in addition to supplying power to the OLED unit. For example, see EP2993713, US2010148665 and US2001 / 033135. In addition, having high metal coverage provides additional protection for the OLED unit and its packaging below. The flat electrical connectors should cover at least 1% or more of the surface area of ​​the circuit board together, desirably 6% or more. One flat electrical connector can be larger than the other. In this case, it is desired that the smaller one covers at least 1% of the surface, while the larger one covers at least 5%. In some embodiments, the coverage of the electrical connector should be at least greater than the emission area of ​​the lighting panel. In these embodiments, the total coverage is desirably at least 65% or more of the circuit board, or most desirably at least 80% or more of the circuit board.

[0065] The extension tab on the flexible printed circuit board can be made of the same material as the main body of the circuit board, or made of a different material. The main body of the circuit board and the extension tab can be one component or two separate components. If it is a separate component, there is a flexible joint between the two. For example, the extension tab can be attached to the main body of the circuit board by a flexible tape. In such an embodiment, the flat electrical conductor should extend continuously on the joint. Most desirably, the flexible printed circuit board has an integral bendable extension tab; that is, the circuit board and the extension tab form a continuous unit of the same material. The extension tab (when not bent as in Figures 1-2) is not located above the emission area of ​​the light emitting unit. The extension tab can extend along the entire edge of the circuit board, but it is more desirable that the extension tab is smaller than the width of the edge. This is to minimize the area where the total thickness of the panel is thicker whenever the extension tab is folded back onto itself. In addition, it is easier to bend smaller tabs evenly than tabs that extend over the entire length of the circuit board. Finally, wide tabs will require users to design wider connection areas or lines. On the other hand, a certain width of the tab should increase durability against twisting and thereby damaging the connector on the tab. Desirably, the width of the tab should be at least 5% of the width of the circuit board edge, but less than 80% of the width.

[0066] There may be more than one extension tab on a panel, and one extension tab may be electrically connected to the extension tab of another panel to allow easy interconnection between panels. In some examples, there may even be two or more extension tabs along a single edge. It is most desirable to have one extension tab per device, preferably on a short edge of a rectangular panel.

[0067] The extension tab can be bent so that the flat electrical connection on the extension tab becomes accessible in different directions. There are three modes of operation: a first mode in which the extension tab is not significantly bent, so that the flat electrical connector can be accessed on the same face as the light emitting unit, and the flat electrical connector is oriented in the same emitting direction of the panel (see Figures 1-2); a second mode in which the extension tab is partially bent and oriented so that the flat electrical connector can be accessed along the edge of the panel (see Figure 3); and a third mode in which the bendable extension tab is completely folded back on the circuit board so that the flat electrical connector can be accessed along the non-emitting face of the panel and the edge of the panel (see Figure 4). This allows a single panel to be used for different wiring designs.

[0068] The extension tab is usually bent or folded along the edge of the main body of the circuit board. However, in some embodiments, the position where the extension tab is bent can be located at a certain distance away from the edge of the main body, so that when the extension tab is bent, the extension tab of the circuit board has some unbent parts.

[0069] In those embodiments where the extension tab will be bent, the joining area between the circuit board and the extension tab must be flexible enough to allow the tab to reach the desired angle without cracking or breaking. Therefore, the joining area may have stress reducing features or designs that locally increase flexibility. For example, the joining area between the body and the extension tab may be thinner than either component. Alternatively, the joining area may have an accordion-like structure that relieves bending stress.

[0070] In some flexed orientations of the extension tab, it may be necessary to use an adhesive or support structure to help hold the flexed portion in the desired position. For example, in the configuration shown in FIG. 4 where the extension tab is completely folded back upon itself, there may be an adhesive (e.g., double-sided tape) between the back side of the extension tab (or optional stiffener) and the back side of the circuit board.

[0071] In some embodiments, the reinforcement member (i.e. Figure 1B , 2A 2B) may be attached to the back side of the extended tab towards the end (opposite the surface attached to the OLED light emitting unit / substrate 4). This may make it easier to bend the tab in a reliable manner. Suitably it may be a piece of biaxially oriented PET, such as Mylar, and attached with double sided tape.

[0072] The total length of the extension tab can be selected as desired. In some cases, the extension tab can be cut or trimmed to a selected length after being bent to a desired orientation. For example, Figure 3B The extension tab 8 in the circuit board is bent at a 90° angle; however, the end of the extension tab is above the plane of the circuit board 6. If desired, this portion can be trimmed off. The extension tab can include structural features to enable cutting or trimming. Desirably, the ratio of the length of the extension tab to the length of the circuit board body is at least 1:100 but less than 1:2, preferably in the range of 1:50 to 1:10.

[0073] In some embodiments, the extended tabs together with the flat electrical connections may be covered (in whole or in part) with a non-conductive material. This may protect the flat electrical connectors and / or associated contact pads from accidental contact. Alternatively, the cover may hide or protect the electrical connections when not in use.

[0074] For flexible panels, the panel should be able to be bent to a radius of at least 100 mm.

[0075] In the above description, reference is made to the accompanying drawings forming a part thereof, and specific embodiments that can be implemented are illustrated in the accompanying drawings by way of illustration. These embodiments are described in detail to enable those skilled in the art to implement the present invention, and it should be understood that other embodiments may be adopted and that structural, logical and electrical changes may be made without departing from the scope of the present invention. Therefore, the description of any exemplary embodiment should not be construed as restrictive. Although the present invention has been described for illustrative purposes, it should be understood that such details are only for this purpose, and those skilled in the art may make changes without departing from the spirit and scope of the present invention.

[0076] Parts List

[0077] C Tab center line, short and long dashed lines

[0078] X Distance to the left of tab 8

[0079] Y Distance to the right of tab 8

[0080] 2 Flexible light management unit

[0081] 4 Light emitting unit / substrate

[0082] 6 Flexible circuit board

[0083] 7 Optional adhesive layer

[0084] 8 Bendable extension tab with wire

[0085] 10 Electrical connection wire

[0086] 11 Optional pad for electrical connection to external power supply

[0087] 12 Electrical connection wires

[0088] 13 Optional reinforcements

[0089] 14 Adhesive

[0090] 16 Attachment parts

[0091] 18 Interconnection Bridge

[0092] 20 Flat electrical contacts bent 90 degrees

[0093] 21 Extension / overhang of light management unit

[0094] 22 A second flat electrical contact bent 90 degrees

[0095] 24 Intersection Area

[0096] 26 Side edge of the circuit board

[0097] 28 Bend 90 degree extension tab

[0098] 30 Folded electrical contacts

[0099] 32 Second folded electrical contact

[0100] 36 Side edge of the circuit board

[0101] 38 Folded extension tab

[0102] 41 Transparent substrate

[0103] 42 OLED light emitting units

[0104] 43 Encapsulation layer

[0105] 44 Contact pads

[0106] 45 Contact pads

[0107] 46 First electrode

[0108] 47 (One or more) organic layers

[0109] 48 Second electrode

[0110] 61 Extension / overhang of circuit board

[0111] 91 Electrical connector

[0112] 92 Electrical connector

[0113] 100 Lighting panel with unbent extension tab

[0114] 200 Lighting panel with 90 degree bent extension tab

[0115] 300 A lighting panel having folded extension tabs.

Claims

1. A flexible lighting panel having an emitting surface and an opposing surface, comprising: a light emitting unit comprising at least one electroluminescent layer between a first electrode and a second electrode on a flexible substrate, thereby forming an emission area, the light emitting unit having at least two electrical contact pads, each of which is individually in contact with the first electrode or the second electrode and is located in a non-emitting area of ​​the substrate, - a flat flexible printed circuit board having at least one bendable extension tab, wherein the circuit board is located on a side of the light emitting unit opposite to the substrate; an area of ​​the circuit board excluding the bendable extension tab is equal to or larger than an emission area of ​​the light emitting unit and overlaps with it; and -The circuit board has at least two flat electrical connectors, which are on the surface of the circuit board facing the light emitting unit and are in electrical contact with the contact pads of the light emitting unit; the flat electrical connectors are located on the bendable extension tab of the circuit board and extend along the bendable extension tab of the circuit board for connecting to a power supply.

2. The flexible lighting panel according to claim 1, wherein: The bendable extension tab is partially bent and oriented so that the flat electrical connector can be accessed along an edge of the panel.

3. The flexible lighting panel according to claim 1, wherein: The bendable extension tab is completely folded back on the circuit board so that the flat electrical connector can be accessed along the opposite sides of the panel and the edge of the panel.

4. The flexible lighting panel according to claim 1, wherein: The bendable extension tab is smaller in width than an edge of the circuit board.

5. The flexible lighting panel according to claim 1, wherein: The area covered by the flat electrical connector is at least 65% of the area of ​​the circuit board.

6. The flexible lighting panel according to claim 1, wherein: The flat electrical connectors on the bendable extension tabs are patterned such that a single portion of one of the flat electrical connectors is located between two interconnected portions of the other flat electrical connector.

7. The flexible lighting panel according to claim 6, wherein: The bendable extension tab is positioned along an edge of the panel such that a center of a space between a single portion of one flat connector and one of the interconnecting portions of another flat connector is positioned along a midpoint of the edge of the panel.

8. The flexible lighting panel according to claim 1, wherein: The circuit board is larger in area than the substrate so that a portion of the circuit board overhangs an outer edge of the substrate.

9. The flexible lighting panel of claim 1, comprising a flexible light management unit on the emitting face of the flexible lighting panel, the flexible light management unit completely covering the emitting area and being equal to or larger in area than the emitting area.

10. The flexible lighting panel according to claim 9, wherein: The flexible light-management unit is larger in area than the substrate such that a portion of the light-management unit overhangs an outer edge of the substrate.

11. The flexible lighting panel according to claim 10, wherein: The circuit board is larger in area than the substrate so that a portion of the circuit board overhangs an outer edge of the substrate.

12. The flexible lighting panel according to claim 11, wherein: The light management unit and the overhanging portion of the circuit board are bonded together by adhesive or mechanical force.

13. The flexible lighting panel according to claim 1, wherein: The substrate is transparent so that light from the light emitting unit is emitted through the substrate.

14. The flexible lighting panel according to claim 1, wherein: The flexible printed circuit board comprises a plastic or polymer carrier with a total thickness not exceeding 0.2 mm.

15. The flexible lighting panel of claim 1, wherein: The light emitting unit is an OLED.

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