Toshiyuki Urano

Synthesis and optical properties of a new class of pyrromethene–BF2 complexes fused with rigid bicyclo rings and benzo derivatives

Abstract A new class of boron dipyrromethene (BDP) dyes fused with rigid bicyclo[2.2.2]octadiene units are prepared, which are converted into benzo BDP dyes via a retro Diels–Alder reaction; the absorption and fluorescence spectra of the new dyes are discussed.

Study of radical generated from coumarin dye-sensitized photo-initiator systems in high-speed photopolymer coating layers using laser flash photolysis

Radical generation from photoinitiation systems containing carbonylbiscoumarin dye with a radical-generating reagent, 3,3′-carbonylbis[7-(diethylamino)-2H-1-benzopyran-2-one] (KCD-DA), with 2,2′-bis(2-chloro-phenyl)-4,4′5,5′-tetraphenyl-1, 1′-bi-1H-imidazole (BI) in a poly(methyl methacrylate) film has been investigated by laser flash photolysis using a total reflection cell. n n n nImidazolyl radical (Im·) was predominantly generated from carbonylbiscoumarin triplet-sensi-xadtized decomposition of BI, the quantum yield, ΦoIm· of Im· at an infinite concentration of BI was measured, ΦoIm·u2005=u20051.3. The high quantum yield, ΦoIm·, implies an efficient KCD-DA triplet-sensitized photoinitiation system containing BI. Copyright

Photopolymerization mechanisms of acrylates in poly(methyl methacrylate) films

Photoinitiation processes for photopolymer coating layers have been investigated with respect to quenching rates by a laser flash photolysis using a total reflection cell, as well as to the decomposition-quantum yield of a sensitizer dye and a radical-generating reagent by a gel permeative chromatographic analysis (GPC); the sensitizer dye,2-[p-(diethylamino)styryl]naphtho[1,2-d]-thiazole (DNT) and the radical-generating reagent, 2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetraphenyl-1,1′-bi-1H-imidazole (BI). From experiments using flash photolysis, strong fluorescence was observed at excitation of 355 nm laser pulse, though no transient absorption was observed. The fluorescence was statically quenched by BI with a quenching distance, Ru2005=u200511 A. From the experiments using GPC, the high-quantum yield of decomposition (Φ) was obtained as Φ (DNT)u2005=u20053 and Φ (BI)u2005=u20059 for DNT and BI in the presence of acrylate monomers, trimethyrolpropanetri-acrylate (TMPTA), at 488 nm exposure of 3.36 mJ cm which was required to form a photo-hardened image, however no decomposition of DNT and BI was detected in the absence of TMPTA. The results imply that the photoinitiator system undergoes efficient static-dye sensitization and efficient polymerization of the acrylate monomers accompanied with the chain decomposition of DNT and BI. Copyright

Sensitizer dyes and sensitization mechanisms in photopolymer coating layer

Quenching ofimidazoyl radical (Im ) formed in photoinitiator systems comprising an aminostyryl dye and a radical generating reagent by a 2mercaptobenzothiazole (MBT):aminostyryl-dye; 2-[p-(diethylamino)styryl]naphtho[1,2-d]thiazole (NAS), radical generating reagent; 2,2-bis(2-chlorophenyl)-4,4,5,54etraphenyl-1,1-bi-lWimidazole (BI) in a poly(methyl methacrylate) film has been investigated by laser flash photolysis using a total reflection cell.

Laser diode (LD) imaging and photopolymers for LD imaging

The laser photopolymers and the laser imaging systems equipped with various laser diodes such as 410 nm-Violet laser, 532 nm-frequency-doubled laser and high-power- infrared laser are presented. The photopolymers performances in sensitivity, resolution and safelight character dependent on the wavelength and power of laser light are discussed.

Azide photoresist for thermal-laser imaging

AbstractTwo azide-type compounds for thermal-laser photoresists have been investigated. One was an azide-pendant polyvinyl ether) as a binder polymer for positive imaging, and the other was a cyanine dye azide for negative imaging. The positive photoresist, which was composed of nigrosine as an infrared (IR)-absorbing dye and an azide-pendant polyvinyl ether), and the negative photoresist, which was composed of a Novolak resin and a cyanine dye azide as an IR-absorbing dye, were exposed by scanning a light spot of 15 mm from a 780 nm, 30 mW laser, giving sensitivities of 340 and 500 mJ/cm2 for the positive and the negative photoresist.

Laser Flash Photolysis in High-Speed Photopolymer Coating Layers: Elucidation of Radicals Generated from Coumarin Dye-Sensitized Photoinitiator Systems

Radical generation from photoinitiation systems containing carbonyl-biscoumarin dye with a radical-generating reagent, 3,3-carbonylbis[7-(diethylamino)-2H-1-benzopyran-2-one](KCD-DA), with 2,2-bis(2-chlorophenyl)-4,4,5,5-tetraphenyl-1,1-bi-1H-imidazole (BI) in a poly(methyl methacrylate) (PMMA) film have been investigated by laser flash photolysis using a total reflection cell. The imidazolyl radical(Im.) was predominantly generated from a carbonylbiscoumarin triplet-sensitized decomposition of Bl, where the quantum yield, Φ Im 0 , of Im. at an infinite concentration of BI was measured as Φ Im 0 = 0.5-1.4 The high quantum yield, Φ Im 0 , implies an efficient KCD-DA triplet sensitized photoinitiation system containing BI.

Laser Flash Photolysis in High- Speed Photopolymer Coating Layers: Elucidation of Radical Generated from Coumarin Dye Sensitized Photo- initiator Systems

Abstract Radical generation from photoinitiation systems containing carbonylbiscoumarin dye with a radical-generating reagent, 3,3′-carbonylbis[7-(diethylamino)-2H-l-benzopyran-2-one](KCD-DA), with 2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetraphenyl-1,1′- bi- 1H- imidazole (BI) in a poly(methyl methacrylate) (PMMA) film have been investigated by laser flash photolysis using a total reflection cell. Imidazolyl radical(Im ·) was predominantly generated from carbonylbiscoumarin triplet sensitized decomposition of BI, the quantum yield, φ 0 1 m · of Im · at an infinite concentration of BI was measured, φ 0 1 m · =0. 5 ∼ 1.4. The high quantum yield, φ 0 1 m · implies an efficient KCD- DA triplet sensitized photoinitiation system containing BI.