Light-curable monomer and resin formulations are increasingly developed, due to the rapid growth of the industrial applications in various aeras, such as coatings and varnishes (optical fibers, wood, plastics, papers ...), adhesives, dental and medical equipment, inks, metal decoration, flooring, imaging, microelectronics [1][2]. One of the most widely used reaction is a light-induced polymerization [3] which readily transforms a liquid resin into a solid film. Improvement of the systems requires further investigation [4] on the (photo)-physical and (photo)-chemical processes involved (in particular, the photoreactivity of sensitizers used to start the reaction) and new ideas concerned with the use of powerful irradiation devices such as lasers in the case of specific applications: direct writing of microcircuits, 3D machining, information storage, manufacture of holographic optical elements [5].

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The color filter for liquid crystal display(LCD) has been developed about 7 years ago in order to fabricate poli-silicon-TFT active matrix LCD. The CF for CCD was popular at that time, but the different characteristics had to be given to the LCD-CF owing to producing good color reproducibility on Pocket Color LCTV. Nowadays, the large size CF is required for the Lap-Top computer display, this size will be more than 10 inch diagonal. Many kinds of CF have been generated for the LCD applications, however, the ideal CF that is applied for all kinds of LCDs is not still be developed, so the situation of the CF market is very complicated now.
We LCD makers have several problems to fabricate those large size CF on the high yield, because the severe color uniformity and low fabrication cost are required as indispensable condition. In addition to that, very strict surface flatness on CF is necessary for performing good image quality. In this paper, I will explain about recent state of development about the CF for the active and the non-active LCDs.

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The imaging process and the spontaneous coupling effect between the diazosalt and the coupler are discussed from some experimental studies. By means of the inhibition of spontaneous coupling effect and the adequate matching of photosensitizers and the couplers, a series of diazo-type microfilms with highr resolution, high optical density and high contrast were developted. The achieved resolution is over 29001p/mm.

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Chitosan, which is deacetylated chitin, has a free amino group which promotes its solubility in some solvents, particularly those that are acidic in nature. The amino group also enhances its reactivity toward chemical reagents.
In this paper, the chitosan-ammonium dichromate (CT-AD) positive polymer was reported. This positive photopolymer is different from ordinary negative photopolymers in response to actinic light and resulting image. It is soluble in aqueous solution, and can be developed in mildly acidic solution. Cr (VI) of ammonium dichromate used as sensitizer was reduced to Cr(II) through the light absorption. The mechanism of the photodecomposition reaction of the CT-AD polymer is dependent initially on the transition of the chromium from a high to low state of oxidation, followed by the decomposition of the initial cross-linked structure of the CT-AD polymer.
In this work, the chitosan-ammonium dichromate film was irradiated by UV light, and the mechanism of the photoreaction of the film was investigated. The electric conductivity of the CT-AD in water solution and of gelatin-AD solution were measured against the UV exposure time in order to prove the photodecomposition reaction in CTAD.
The values of quantum yield of the HcrO₄^- reaction in water solution of CT-AD were measured.

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Photoreaction of di- and tetraolefinic compounds has been investigated in the organized system such as crystals and Langmuir-Blodgett (LB) films. Olefinic compounds studied include the following series: p-phenylenedi- acrylic acid (p-PDA) monoesters, p-PDA diesters and 5, 5′-(1, 4-phenylene)- bis(2-cyano-2, 4-pentadienoic acid) (PCPA) diesters. In the crystalline state, p-PDA monoesters with shorter alkyl chains, are photoreactive yielding oligomers, while both p-PDA and PCPA diesters gave crystalline polymers on irradiation. The photoreaction in these crystals proceeded by cycloaddition of double bonds forming cyclobutane rings. Crystal structure analysis of these compounds revealed that reaction of p-PDA and PCPA diesters took place topochemically, but that of p-PDA monoesters did not. Regarding LB films, p-PDA monoesters with long-chains gave Z-type LB films and p-PDA and PCPA diesters with long-chains formed Y-type films when mixed with arachidic acid. On irradiation, these films yielded oligomers or p lymers. The spectral data and the molecular area of these compounds indicate that molecular arrangement in each LB films is different from that of crystals. The reaction mechanism was discussed with reference to the molecular alignment.

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We developed a new type of polymer having a high photoconductivity in the visible light region. The polymer is composed of a series of thiophenylene moieties, -C₆H₄S-, and an imide group. The polymer with this type of chemical structure is called polyimide [PI].The casted films of polyamic acid precursors were imidized to PI films and crystallized by annealing at suitable temperatures near the melting points. The thickness of crystallites in the PI film is estimated to be about 100ÅÅ, which corresponds to the 20 polymer chains stacked perpendicular to the axis. In the crystallizing process, both the absorption and the photoconductivity of this film in the visible light region increase extremely. From the UV-visible absorption spectra, we evaluated the optical energy gap, Eg. In the most sensitive polymer, BPDA-Ph3, Eg changed from about 2.5eV in the amorphous phase to about 1.85eV in the crystalline phase. Aromatic rings of thiophenylene moieties and imide rings of the PI films are so stacked that the π-orbitals of both rings are more overlapped, which increases absorption in the visible region. Our highly crystallized PI films with extensively overlapped π-orbitals between the adjacent chains show high photoconductivities. In the crystallizing process the photoconductive property, ημτ, increases in magnitude three orders or more. The most sensitive polymers, BPDA-Ph3 and -Ph5, have ημτ values more than 10^-8cm²/v in the visible region 350-550nm.

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An electron donor, polyvinylcarbazole, and some acceptors such as 2-nitrofluorenone, 2, 5-dinitrofluorenone, 2, 4, 7-trinitrofluorenone and 2, 4, 7- tetranitrofluorenone were synthesized and characterized. Some physico-chemical parameters of the charge transfer complexes composed of these compounds were determined. The results indicate that their photoconductivity depends not only on the electron affinity and ionization potential (related to equilibrium constant, charge transfer amount), but also on the conjugation of the component.

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