Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B33/00—Electroluminescent light sources
  • H05B33/02—Details
  • H05B33/04—Sealing arrangements, e.g. against humidity
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
  • H10K59/10—OLED displays
  • H10K59/12—Active-matrix OLED [AMOLED] displays
  • H10K59/127—Active-matrix OLED [AMOLED] displays comprising two substrates, e.g. display comprising OLED array and TFT driving circuitry on different substrates
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
  • H10K59/80—Constructional details
  • H10K59/87—Passivation; Containers; Encapsulations
  • H10K59/871—Self-supporting sealing arrangements
  • H10K59/8722—Peripheral sealing arrangements, e.g. adhesives, sealants
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
  • H10K59/30—Devices specially adapted for multicolour light emission
  • H10K59/38—Devices specially adapted for multicolour light emission comprising colour filters or colour changing media [CCM]

Definitions

• the present invention relates to organic light emitting devices.
• the present invention relates to a method of sealing an organic light emitting device plate and an active matrix plate sealed together to create a high performance video display.
• Light emitting devices which may be generally classified as organic or inorganic, are well known in the graphic display and imaging art. Among the benefits of organic light emitting devices are high visibility due to self-emission, as well as high power efficiency, and ease of handling of the solid state devices. Organic light emitting display devices may have practical application for television and graphic displays, as well as in digital printing applications.
• An organic light emitting display device is typically a laminate formed on a substrate such as soda-lime glass.
• a light-emitting layer of a luminescent organic solid, as well as adjacent semiconductor layers, are sandwiched between a cathode and an anode.
• the semiconductor layers may be hole-injecting and electron-injecting layers.
• the light-emitting layer may be selected from any of a multitude of light emitting organic solids.
• the light-emitting layer may consist of multiple sublayers.
• a potential difference When a potential difference is applied across the cathode and anode, electrons from the electron-inj ecting layer, and holes from the hole-inj ecting layer are inj ected into the light-emitting layer. They recombine, emitting light.
• numerous light emitting devices are formed on a single substrate and arranged in groups in a regular grid pattern. Several light emitting device groups forming a column of the grid may share a common cathode, or cathode line. Several light emitting device groups forming a row of the grid may share a common anode, or anode line. The individual light emitting devices in a given group emit light when their cathode and anode are activated at the same time. Activation may be by rows and columns or in an active matrix with individual cathode or anode pads.
• Organic light emitting devices have a number of beneficial characteristics. These include a low activation voltage (about 3 to 6 volts), fast response when formed with a thin light-emitting layer, and high brightness in proportion to the inj ected electric current. By changing the kinds of organic solids making up the light-emitting layer, many different colors of light may be emitted, ranging from visible blue, to green, yellow, and red. Organic light emitting devices are currently the subject of aggressive investigative efforts.
• Organic light emitting devices need to be protected from the atmosphere.
• the light emitting organic material in the light-emitting layer can be highly reactive.
• the material is susceptible to water, oxygen, etc. Moisture and oxygen may cause a reduction in the useful life of the light emitting device.
• the cathode and anode may also be affected by oxidation.
• One disadvantage of oxygen and moisture penetration into the interior of the organic light emitting device is the potential to form metal oxides at the metal-organic interface. These metal oxide impurities may allow separation of the cathode or anode and the organic in a matrix addressed OLED, especially the oxidation sensitive cathode, such as, Mg-Ag or Al-Li. This can result in the formation of dark non- emitting spots (i.e., no illumination) because no current flows through the area of the separation.
• the present invention is directed to a method for processing active matrix organic light emitting device displays with nontransparent substrates, such as, for example, silicon.
• Non-transparent substrates provide a low cost method for obtaining active matrix circuitry and high performance drivers, along with an opportunity to integrate other system or display functions into small-medium size displays.
• the organic light emitting device can be fabricated using this method without the need for silicon substrate planarization, and with optimized organic light emitting device structures on an independent glass plate.
• the present invention is directed to a method of forming an active matrix organic light emitting device display.
• the method includes the steps of providing an organic light emitting plate assembly, providing an active matrix plate assembly, and sealing the organic light emitting plate assembly to the active matrix assembly.
• the active matrix plate assembly may include a substrate, drive circuitry formed thereon, and at least one pixel pad.
• the at least one pixel pad may be formed from an electron injector material.
• the electron injector material may be selected from one of the group consisting of Mg+Al, Al+Li, LiF/Al and CsC.
• the method may further include the step of cleaning the at least one pixel pad prior to the step of sealing the organic light emitting plate assembly to the active matrix plate assembly.
• the cleaning step may include the step of ion beam cleaning of at least one pixel pad.
• the organic light emitting plate assembly may include a substrate, a conductor layer and at least one OLED layer.
• the organic light emitting plate assembly may further include at least one color filter.
• the step of sealing the organic light emitting plate assembly to the active matrix plate assembly may comprise the steps of locating the organic light emitting plate assembly and the active matrix plate assembly in a sealing environment, and securing a perimeter of the organic light emitting plate assembly to a perimeter of the active matrix plate assembly.
• the environment may be one of a vacuum environment, an inert gas environment and a moisture absorbing gas environment.
• the step of securing the perimeter of the organic light emitting plate assembly to the perimeter of the active matrix plate assembly may include sealing the perimeter of the organic light emitting plate assembly to the perimeter of the active matrix plate assembly with a fused metal seal.
• the step of securing the perimeter of the organic light emitting plate assembly to the perimeter of the active matrix plate assembly may include sealing the perimeter of the organic light emitting plate assembly to the perimeter of the active matrix plate assembly with a polymer.
• the polymer may be a low moisture diffusivity polymer.
• the low moisture diffusivity polymer may be a two-component adhesive, or cured by heat or ultraviolet light.
• the sealing of the organic light emitting plate assembly to the active matrix plate assembly may be done in a low-pressure inert environment by bringing the surfaces of the two assemblies into intimate contact, and may include the application of pressure and/or heat.
• the present invention is also directed to a high performance display including an organic light emitting device, an active matrix substrate; and an assembly for bonding the organic light emitting device to the active matrix substrate.
• the organic light emitting device may include a substrate, at least one conductor formed on the substrate, and a first insulator layer formed on the conductor.
• the organic light emitting device may include a color filter disposed between the substrate and the conductor.
• the organic light emitting device may include a color conversion filter disposed between the substrate and the conductor.
• the substrate may be a thin transparent material.
• the active matrix substrate may include a second substrate, independently addressed pixel pads, and driver circuitry.
• the active matrix substrate may be fabricated on a non-transparent substrate.
• the independently addressed pixel pads may be produced from an electron injector material with high vertical conductivity and low horizontal conductivity.
• the independently addressed pixel pads make contact with the organic light emitting device.
• the independently addressed pixel pads may be elevated by at least one insulator.
• the independently addressed pixel pads may be elevated by stacking the pixel pads on top of at least one lower silicon circuit structure.
• the organic light emitting device and the active matrix substrate may be sealed together in an inert or moisture-reactive gas environment.
• the organic light emitting device and the active matrix substrate may be sealed together using a fused metal seal.
• the organic light emitting device and the active matrix substrate may be sealed together using at least one low moisture diffusivity polymer.
• the low moisture diffusivity polymer may be a non-solvent containing epoxy or acrylic.
• the low moisture diffusivity polymer may be a UV or heat cured adhesive.
• FIG. 1 is a side view of an active matrix organic light emitting display device prior to assembly according to the present invention
• Fig. 2 is a side view of the active matrix organic light emitting display device in an assembled state according to the present invention.
• Fig. 3 is a side view of an active matrix organic display device prior to assembly with OLED stacks on both assemblies according to the present invention.
• the present invention is directed to an improved light emitting device 1 that includes an organic light emitting plate assembly 10 that is secured to an active matrix plate assembly 20.
• the organic light emitting plate assembly 10 includes a substrate 110.
• the substrate 110 is preferably formed from a transparent material such as, for example, mylar or glass. It, however, is contemplated by the inventors of the prevention that other suitable materials may be used for forming the substrate 110. This substrate might be particularly flat and flexible.
• a conducting layer 120 is formed on the substrate 110.
• the conducting layer 120 is preferably formed from indium tin oxide (ITO).
• ITO indium tin oxide
• a planar OLED stack 130 is formed on the conducting layer 120.
• the OLED stack 130 may include an electron inj ector material with high vertical conductivity and low horizontal conductivity.
• the electron injector material may be LiF.
• the organic light emitting plate assembly 10 may include at least one color changing filter 140.
• the at least one color changing filter 140 is probably located between the substrate 110 and the conducting layer 120.
• the surfaces of the OLED materials and the filters should be smooth and nearly planar to ensure proper orientation with the plate assembly 20 after fabrication.
• the OLED materials may be patterned into red, green and blue emitters to produce a color display.
• a color display may also be produced by patterning part of the color OLED emitter on one substrate and the other two color OLED emitters on another substrate, as shown in Fig.3. This makes direct shadow masking of direct color organic light emitting display devices more simple.
• the active matrix plate assembly 20 includes a substrate 210.
• the substrate 210 is preferably formed from silicon or another suitable substrate material.
• the active matrix plate assembly 20 further includes driver circuitry and other system related electronics 220.
• the matrix plate assembly 20 preferably includes CMOS drivers and transistor and capacitor cells.
• the active matrix plate assembly 20 also includes at least one pixel pad 230.
• Each pixel pad 230 corresponds to a pixel on the display device and is independently addressable.
• Each pixel pad 230 is preferably formed from a good quality electron injector material.
• the electron injector material may be formed from Mg+Ag, Al+Li, LiF/Al or CSC. The present invention is not limited to these materials or polarlity; rather, it is contemplated that other suitable injector materials may be used.
• Each pixel pad 230 must be sized such that it contacts the OLED stack 130 when the organic light emitting plate assembly 10 is secured to the active matrix plate assembly 20. A thickness of between 0.5-10 microns is acceptable for this purpose.
• the pixel pads 230 may be elevated by other structures, such as, for example, a thick insulator and a via plug. Additionally, the pixel pads 230 may be stacked on top of lower silicon circuit structures. Additionally, a shallow trench might be etched for the seal.
• a sealing assembly 30 is provided to secure the organic light emitting plate assembly 10 to the active matrix plate assembly 20.
• the sealing assembly 30 preferably includes a first sealing assembly 310 formed on the organic light emitting plate assembly 10 and a second sealing assembly 320 formed on the active matrix plate assembly 20.
• the sealing assembly 30 may be a fused metal seal.
• the sealing assembly 30 is not limited to a metal seal; rather, low moisture diffusing polymers including but not limited to a non-solvent containing a UV or heat cured adhesive may be used.
• the active matrix plate assembly 20 is formed by fabricating the driver circuitry and other system related electronics 220 on the substrate 210.
• the active matrix plate assembly 20 may be fabricated using known techniques.
• the organic light emitting plate assembly 10 is formed by fabricating an OLED structure on a substrate 110.
• the OLED structure may be formed using known techniques.
• the OLED structure includes the conducting layer 120, the planar OLED stack 130.
• the OLED structure may further include at least one color changing filter 140.
• a first sealing assembly 310 is formed along the perimeter of the organic light emitting plate assembly 10.
• a second sealing assembly 320 is formed along the perimeter of the active matrix plate assembly 20.
• the plate assemblies 10 to 20 are located in a vacuum or inert gas environment.
• the first and second sealing assemblies 310 and 320 are then brought into contact. After sealing, the light emitting device 1 is removed from the low-pressure environment. Under the influence of atmospheric pressure, the plate assemblies 10 to 20 move into intimate contact such that each pixel pad 230 is in contact with the organic light emitting plate assembly 10. This works when the pressure of the inert gas inside is sufficiently below the ambient pressure.
• Non- vacuum sealing can best be performed by applying pressure in the center of one or both of the plastic assemblies 10 to 20.
• one or both of the plastic assemblies 10 to 20 may be bowed prior to sealing.
• the pixel pads 230 may be ion bean cleaned prior to sealing the plastic assemblies 10 to 20 together.
• the above-described method may be used with other TFT active matrix substrates when larger displays are fabricated. This permits more processing options and the ability to build transport displays.
• the above-described method can also be used for passive OLED fabrication where the election injector/conductor lines and ITO/OLED lines cross over at the OLED light generating pixels.
• the OLED structure can be built on either the transparent conductor side or the active matrix side of the plate assembly 10. If the OLED structure is reversed with the hole injector on top, then a gold interface layer can be used on the pixel pads 230.
• a thin Mg+Ag, Al+Li, LiF/Al or CsC layer can act as a transparent electron injector on the transport ITO layer.

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• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Electroluminescent Light Sources (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1998
  • 1998-07-06 EP EP98933170A patent/EP0995183A2/de not_active Withdrawn
  • 1998-07-06 CA CA002296026A patent/CA2296026A1/en not_active Abandoned
  • 1998-07-06 WO PCT/US1998/013935 patent/WO1999003087A2/en not_active Ceased

Non-Patent Citations (1)

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