Ink-Jet Printing of Color Optical Filters for LCD Applications

At the age of multi-media, portable electronic devices such as mobile phones, personal digital assistant and handheld gaming systems have increased the demand for high performance displays with low cost production. Inkjet printing color optical filters (COF) for LCD applications seem to be an interesting alternative to decrease the production costs. The advantage of inkjet printing technology is to be fast, accurate, easy to run and cheaper than other technologies. In this master thesis work, we used various disciplines such as optical microscopy, rheology, inkjet printing, profilometering and colorimetry. The specific aim of the thesis was to investigate the feasibility of using company-A pigment formulation in inkjet production of COF for active matrix LCD applications. Ideal viscosity parameters were determined from 10 to 20mPa·s for easy inkjet printing at room temperature. The red pigments used are fully dispersed into the solvent and present an excellent homogenous repartition after printing. Thickness investigations revealed that the printed COF were equal or slightly thicker than typically manufactured ones. The colorimetry investigations demonstrated color coordinates very close to the NTSC red standard. LED backlighting seems to be a valuable solution to combine with the printed COF regarding to the spectrum and color analysis. The results on this thesis will increase the understanding of inkjet printing company-A pigments to produce COF for LCD applications.

Evaluation of surface treatment techniques for polypropylene andimplementation of a method for testing ink adhesion

If a plastic material is used as a print bearer there are a need of a special surface treatment to get agod and durable printing. The most used surface treatment technique for the moment is coronatreatment. This kind of treatment has unfortunately showed not to be so durable in the long term.Plasma treatment which in this case uses different kind of gases in the treatment of polypropyleneis shown as a more effective treatment in this project. When the plasma treated surface has beenprinted is the good quality last much longer and the adhesion between the ink and the surface isremained. To test this adhesion is for the moment a standard used (ASTM D3359). This standardhas appeared unstable and dependent at many different factors, which gives a big variation in thetest results. Because of this has new test methods been carried out to give a more even and morereliable result in the test of the adhesion.

Study of ink mileage and print through

This report contains a study of ink mileage, show through and other mechanisms that are important inthe study of substrate printability. These mechanisms have an impact on how ink will react on paper.To develop a substrate that provides good ink mileage and less show through requires a closer studyof substrate characteristics.Substrates with different characteristics have been tested by a technique developed for this projectcalled modified ink mileage. Ink mileage is a method to determine how much ink that is required for acertain target density. Further tests on the same substrates have been done including print throughand surface roughness measurements.