OLED Technologies B.V.
sm-OLED
Together with our partners, OTBv is developing next generation materials. It combines the long lasting lifetimes of small molecule OLED with the ease of inkjet printing. The materials are a mixture of a small molecule matrix with phosphorescent molecules with high efficiencies and long lifetimes. The small molecules are chemically modified to make them soluble in organic solvents. By selecting the right solvent system, the material is made printable.The OLED materials are applied in very thin layers; only about 10 mg of material is needed for a laptop screen.
Together with our partners, OTBv is developing next generation materials. It combines the long lasting lifetimes of small molecule OLED with the ease of inkjet printing. The materials are a mixture of a small molecule matrix with phosphorescent molecules with high efficiencies and long lifetimes.
The small molecules are chemically modified to make them soluble in organic solvents. By selecting the right solvent system, the material is made printable.
The OLED materials are applied in very thin layers; only about 10 mg of material is needed for a laptop screen.
ORGANIC VAPOR JET PRINTING
A new development in the fabrication of OLED displays is Organic Vapor Jet Printing. It is a direct and efficient deposition method, using a stream of small molecules in a hot carrier gas. Since the molecules are used in the dry state, there is no need to make the molecules soluble first, dissolve them and then dry the layers again after printing. The absence of a solvent also opens the way to make more complex stacks of materials, hereby improving lifetime and efficiency. For example additional transport layers are used to balance the recombination of charges in the emissive layer.The OVJP process works by heating the required OLED small molecules in a furnace under vacuum. A carrier gas flows through the furnace, taking evaporated molecules in its stream. The gas with OLED material flows to a specifically designed multi-nozzle printhead, and is accelerated inside the nozzles. The jet that is formed at the outside of the nozzles impinges on a cold substrate and the light carrier gas molecules are quickly dispersed, while the organic molecules condense on the surface. OLED displays are made by moving the printhead over the substrate. The handler moves substrates from the print line to a handling interface where the substrates are put onto the substrate orientation plate (SOP). The substrate remains on the SOP during the TFE process steps. The substrate alignment is fixed on an alignment module and then transferred onto a carrier into the vacuum tool where it is oriented vertically. Carriers transport SOPs and substrates via the transport chamber of the vacuum tool to the various process modules. After all processes are executed SOP and substrate are removed from the vacuum tool and separated.The finished substrates are put into a cassette for manual unloading from the PCAP20.Each substrate is cut into separate modules that are further processed into display packages (including drive electronics).
A new development in the fabrication of OLED displays is Organic Vapor Jet Printing. It is a direct and efficient deposition method, using a stream of small molecules in a hot carrier gas. Since the molecules are used in the dry state, there is no need to make the molecules soluble first, dissolve them and then dry the layers again after printing. The absence of a solvent also opens the way to make more complex stacks of materials, hereby improving lifetime and efficiency. For example additional transport layers are used to balance the recombination of charges in the emissive layer.
The OVJP process works by heating the required OLED small molecules in a furnace under vacuum. A carrier gas flows through the furnace, taking evaporated molecules in its stream. The gas with OLED material flows to a specifically designed multi-nozzle printhead, and is accelerated inside the nozzles.
The jet that is formed at the outside of the nozzles impinges on a cold substrate and the light carrier gas molecules are quickly dispersed, while the organic molecules condense on the surface. OLED displays are made by moving the printhead over the substrate.
The handler moves substrates from the print line to a handling interface where the substrates are put onto the substrate orientation plate (SOP). The substrate remains on the SOP during the TFE process steps. The substrate alignment is fixed on an alignment module and then transferred onto a carrier into the vacuum tool where it is oriented vertically.
Carriers transport SOPs and substrates via the transport chamber of the vacuum tool to the various process modules. After all processes are executed SOP and substrate are removed from the vacuum tool and separated.
The finished substrates are put into a cassette for manual unloading from the PCAP20.
Each substrate is cut into separate modules that are further processed into display packages (including drive electronics).
OLED PRINTING
The production of full color OLED displays based on polymer OLED materials is done by inkjet printing. The advantage of inkjet printing is the very efficient material utilization, since materials are only deposited where needed. Polymer OLED materials are dissolved in organic solvents, making them printable. The choice of the proper solvent system in combination with a specific substrate pretreatment guarantees that the printed layers (after drying) are homogeneous and continuous.
Each pixel contains a stack of functional materials, a Hole Injection Layer, an Interlayer and the Polymer OLED, sandwiched between an Anode and Cathode.
Three different types of Polymer OLEDs are used which emit either Red, Green or Blue light. Each type of LEP is printed in its designated subpixels. Three subpixels with RGB make up one white pixel. With these 3 colors, a full-color display can be made. With inkjet printing, pixel resolutions of 70 micrometers can be achieved.
Substrate with
Empty Pixels
Printing of Green
Polymer OLED
Printing of Red
Printing of Blue
THIN FILM ENCAPSULATION
OTB’s unique Thin Film Encapsulation is a ultra-thin multilayer composite which seals the sensitive OLED materials from water and oxygen from the environment. The organic-inorganic barrier stack has a resistance to water which is 100.000 times better then the best polymeric sealants.
Advantages of Thin Film Encapsulation (TFE)
- Cost reduction through a reduced bill of materials
- Thin displays and with arbitrary shape
- Key enabler for flexible applications
- The required route for large area OLEDs products
The OLED Displays produced on Oled Technologies’ lines are protected from the environment by Thin Film Encapsulation (TFE). Encapsulation is necessary to protect the OLED materials from water vapor which causes degradation of the functional layers (OLED materials) reducing their lifetime.
GEN4 SUBSTRATE
The Gen size of glass substrate is an indication of the length and width of the substrate. The substrates are delivered including the TFT driving transistors for the individual OLED pixels and can be fed into OTB’s equipment (PCAP20 and PCAP48) to have the OLED active layers, cathode and encapsulation deposited.
The TFE consists of alternating layers of inorganic and organic materials which prevent water vapor transport from the environment to the functional layers. The top layer shown is an anti scratch layer to mechanically protect the device.
The Thin Film Encapsulation processes are carried out partly under vacuum and partly under an inert gas atmosphere to ensure that the functional layers are not exposed to oxygen and water vapor during processing.
Thin Film Encapsulation enables the Oled Technologies production lines to run at short tact time. The displays produced are cheaper and thinner than glass encapsulated displays. The lifetime of TFE displays has been proven to be greater than or equal to that of glass encapsulated displays.
OTB’s PCAP20 uses Gen1 (14” x 14”) glass substrates. As an example, this can be used to produce 12 3.5” displays per substrate, or one 14” wide screen display.
OTB’s PCAP48 uses Gen4 (730 mm x 920 mm) glass substrates. As an example, this can be used to produce 90 3.5” displays per substrate, or 6 14” wide screen displays.
SUBSTRATE MOVEMENT AND HANDLING
The substrates are delivered in a transport box. They are unloaded one by one by hand into the glass washer. A robot transfers them from the wash line to a cassette which is manually put in a drying oven.
After drying, the cassette is placed in a loading module from which a handler loads the substrates into the process modules of the print line.
This print line contains etchers for pretreatment, printers for the various OLED layers, dry bake ovens for baking the materials and conditioners for temporary storage.
