EUROLCDS state of the art clean-room production environment in the Ventspils plant features a total area of 1800 m2. This will house a fully-automated advanced STN production line together with a flexible back-end production facility. In turn, this will allow for flexible low to high volume manufacturing, guaranteeing high quality and a vast array of different specification products.
The front-end production line has been transferred from Optrex Babenhausen plant (in Germany) to Ventspils, Latvia and has been modified by EUROLCDS to accommodate the flexible laser ITO process eliminating the need for expensive time-consuming ITO wet-etching process tooling and allowing for more flexibility in addressing low volume high mix production requirements. Another modification includes creating the LCD panel press process in a vacuum chamber, allowing dispensing of liquid crystal and gasket prior to assembly of the panel (the so-called ODF process). The standard size of processed substrates is 300×400 mm. However, with some modifications, we are also able to accommodate even larger-sized substrates (depending on requirements), up to 400x600mm.
LCD front-end processes
The main processes in the front-end production inline flow are:
• Cleaning and washing of ITO coated glass substrates;
• ITO patterning using a high-speed laser system. Due to process flexibility and no tooling requirements high-mix production with no substantial cost penalty is achievable;
• Wet cleaning after laser process;
• Insulation “hard coat” – layers and liquid crystal alignment “polyimide” layers printed by the flexographic method onto glass substrates followed by pre-cure and high temperature thermal curing. Alternatively, the coatings can be deposited by PVD method;
• Mechanical alignment of polyimide layers on inner-surfaces of both substrates mechanically rubbed using velvet-cloth in order to define alignment directions of liquid crystal molecules;
• Cleaning of substrates to allow assembly with small gap sizes;
• Wet or dry application of spacers;
• Automated dispensing of the edge seal gasket and liquid crystal material according to the desired configuration of LCD cells and gap size;
• Assembly and pressing together of both (top and bottom) substrates into a vacuum chamber with consequent UV and thermal curing of the gasket seal;
• Final inspection of assembled LCD substrates (panels).
Back-end process (main plant)
Back-end production flow in the main plant:
• Scribing and separating panels into individuals cells (modules);
• Cleaning of individual cells (modules);
• Application of polarizing and other applicable filter films, lamination;
• Dip coating of antireflective coat;
• Application of various types of connection leads, pins, tabs, and other types;
• Functional and environment testing of finished LCD products.
Physical vapor deposition
From 2019, in addition to traditionally flexoprinted coatings in LCD industry, we offer Physical Vapor Deposition (PVD) coating possibilities in our plant by using state of the art sputtering machine from FHR Anlagebau Gmbh.
PVD coatings coated at the atomic level allows control of structure, density and stoichiometry of the films. Using certain materials and processes, it is possible to develop specifically desired attributes of the physical vapor deposited film like hardness, surface energy, adhesion and more. In the PVD process the high purity, solid coating material is evaporated by bombardment with ions (sputtering). At the same time, a reactive gas is added; it forms a compound with the metal vapor which is deposited on the material surface as a thin, highly adherent coating. A uniform coating thickness is obtained by slowly moving the parts at a constant speed under targets.
Our thin film deposition services include the following capabilities:
Batch processing system by top down sputtering
Substrates on carrier, maximum size up 1.5 x1 m
RF sputter etching (Ar) is used to clean and activate surfaces and enhance adhesion prior to sputter deposition.
Standard transparent conductive layers: ITO and others by request.
Reactive sputtering of oxides and nitrides including: SiOx, Nb2O5, SiON, Si3N4 and others by request.
The machine is capable of DC-, MF- and RF- mode as well as metallic or reactive layer deposition. The modular design also allows to use different deposition technologies in one deposition batch. Films can be deposited as blanket layers or can be patterned via photolithography or laser-cut shadow masks.
Although designed primarily for glass, due to horizontal carrier system, flexible substrates can also be coated. Special care is also taken for cleanliness, starting from particle control and clean room zone over loading/unloading table which is critical for optical grade.
Batch system enables effective production of R&D trials for antireflection and multiple stack coatings. The machine is recipe controlled with complete process data logging capability.
In house profilometer, spectrometer and measurements of surface cleanliness and free energy are available for process controls. More advanced measurement techniques are available at Institute of Solid State Physics, University of Latvia.