|Vacuum assembly machine for OLED, DSSC and E-Paper|
Joyo Engineering is represented in Europe by
Company LCD Printing Rubbing Assembly/Hot Press Vaccum assembly ODF Scribe/Break
Organic light emitting displays OLEDs, OLED lights, dye sensitive solar cells DSSC and electronic papers displays EPD or e-papers are different products but have a similar construction principle. They all consist of cover sheets (glass or foil), top and bottom electrodes and in between some liquid or gel-type or soft organic layer. Here is a short, simplified description of these units:
Organic light emitting displays or OLEDs are consisting of a substrate layer with a transparent conductive layer on which two organic semiconductor layers are deposited. One of these organic layers serves as emitter layer, the other one as a conductive, hole transportation layer HTL. The cathode is formed by a metallic layer. The cell is then closed by a cover layer. OLEDs can be used as a display or also simply as a light source (OLED light).
Dye sensitive solar cells DSSC, also called Graetzel cells are thin film solar cells, which are composed of electrodes, a porous high surface titanium dioxide layer, covered with molecular dye on the surface and an aqueos electrolyte. Light is causing the emmission of electrons from the dye. The titanium dioxide transmits the electron to the transparent anode. Via the iodine containing electrolyte the missing electron in the dye is replaced. A current is induced by sun light.
Electronic paper display EPD oder E-papers consist a substrate layer with a thin reflective electrode, lithographic formed pixel walls, and e-ink, a mixture of charged, colored pigments in a liquid, as well as a transparent top electrode and a cover layer. By applying voltage the pigments change position and dark or white pixels are formed. In most cases, flexible substrates are used.
For manufacturing of organic light emitting displays OLEDs, OLED lights, dye sensitive solar cells DSSC and electronic paper displays EPD or e-papers, similar technics can be used for the assembly of the cells. In all cases, you have a lower substrate with a special coating and an upper glass or foil on which the seal is printed or dispensed already. Then these two sheets have to be assembled under vacuum conditions in order to avoid the inclusion of bubbles into the cell. The two sheets must then be pressed together with a special force in order to make sure, that the distance between substrate and cover sheet is correct. It is important, that the two sheets have enough contact. Pressure should be not too high in order to avoid the squeeze out of the deposition layer or the sealing. Then the sealing has to be hardened in order to establish a stable cell. In many cases, it is an advantage to do hardending while the sheets are still pressed together with an adjusted force.
Joyo Engineering developed an assembly machine for OLEDs, DSSCs and EPDs or E-papers. It consists of a vacuum chamber, which is devided in two parts by a UV transparent foil. First the lower substrate with a deposited layer is loaded into the lower part of a vacuum chamber. Then the second substrate, usually with the seal printed or dispensed onto it is loaded also in the chamber. Both substrates are positioned correctly. After evacuation of the vacuum chamber the two substrates can be brought in contact. The chuck is moving to the upper part of the lower part of the vacuum chamber until it is in contact with the foil, separating the upper from the lower part of the vacuum chamber. When now only the upper part of the vacuum chamber is purged, then the dividing foil is pressing the two substrates together with a force of up to 1 atm. Now a UV light source, which is mounted above the vacuum chamber can be used to illuminate via a photo mask just the sealings. The sealing will be hardened while they are still under pressure. This way, the complete assembly process can be performed in one single machine. This machine can be used with manual loading or fully automatic integrated in an inline manufacturing process. It can be configured to all substrate sizes.
Vaccum assembly machines are very well suited in order to combine cell assembly with integrated filling of the cell with liquid crystals. This technology is called one drop filling ODF-Technology, because the exact volume of liquid crystals which is necessary to fill the cell is dispensed on the lower glass plate before cell assembly is done. This methode requires extremely precise dispensing technology because too much liquid would cause an overflow of the cell during assembly and pressing, while too less liquid would create bubbles in the LCD. Vaccum assembly is necessary in order to avoid gas bubble inclosure.
Joyo Engineering and Crystec will be pleased to engineer a cost effective system to satisfy your most demanding and exacting requirements.
|Crystec Technology Trading GmbH will be pleased to further discuss details with you.|
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