The central part of a PMMA or acrylic resin lens was modified into hydrophobic and the peripheral part to be phydrophilic using teh ArF laser and excimer lamp. PMMA or acrylic resin lens have been used as an intraocular lens for 50 years and is the golden standard in ophthalmology. However, protein and fat are stuck onto the IOL surface after long-term implantation and opacify the surface )after-cataract). Therefore, the central part of the IOL was modified to be hydrophobic to prevent fat and protein deposition; the periphery was made hydrophilic to develop affinity for tissue.
The fluorocarbon thin film and fused silica glass was bonded for an ArF laser light transmittance by using silicon oil. The chemical main structure of the silicon oil has siloxane chains as in the same structure of quartz. This new bonding method was developed with silicone oil and excimer-lamp in an oxygen atmosphere. The silicone oil was put between the fused silica glass and the fluorocarbon (FEP), and an excimer-lamp was irradiated. The silicon oil ((-O-Si(CH3)-O)n) was photo-dissociated and reacted with the oxygen adsorbed on the silica glass surface to produce a SiO2. On the other hand, the H atoms photo-dissociated from the silicon oil pulled out the F atoms of the FEP. As a result, the FEP and the silica glass were combined. The results showed that the silicon oil changed to silica glass by the excited oxygen, which improved the UV rays under 200nm transmittance.
Bacteriologic cultivation on a fluorocarbon-resin FEP surface has been successfully demonstrated by a photochemical modification method using an ArF excimer laser and a boric-acid aqueous solution. The resin surface was photochemically defluorinated with boron atoms which were produced by the photodissociation of the boric-acid aqueous solution; dangling bonds of carbon atoms in the surface were bonded with OH radicals which were also produced by the photodissociation. The sample surface was area-selectively modified into hydrophilic property by the exposure of ArF excimer laser with a mask-pattern image. A culture medium of the Czapeck-dox agar was fabricated on the hydrophilic parts, and a mold was cultured in the agar at 25°C and 7 days.
This paper shows the mechanism of fracture formation of a granite caused by thermal stress in the case of applying the impulsive CO2 laser beam to its surface.The equation for heat conduction in solid according with the conditions of the laser beam irradiation is solved, and the temperature distribution in the rock for each time elapsed is calculated by making use of its thermal properties in various temperature surroundings by employing the laser flush method.Applying the temperature distribution to the common axi-symmetric finite element method, the thermal stresses in the rock can be obtained.In this process for setting up external forces of the nodal points the ‘thermal’ Young's modulus is used instead of conventional Young's modulus.Appropriateness of above temperature calculation is confirmed experimentally by two ways.One is to observe the distribution of the surface temperature by infra-red ray TV camera, and the other is to measure the surface displacement perpendicular to it by He-Ne laser holography.The simulation is made for the fracture propagation with time elapsed.The Griffith theory is adopted for the evaluation of fracturing in each element mesh in FEM.In this simulation it has become clear that the greater part of the fractured elements occurs at tensile stress region, and the fractured region caused only by the thermal stress is limited.
An oxidizing agent is needed for silicone oil to be photo-oxidized with Xe2 excimer-lamp. However, the lamp light did
not reach the silicone oil on the surface of the substrate satisfactorily, and the photo-oxidation reaction of the silicone oil
layer was hard to take place properly. In order to find the appropriate conditions for supplying the proper amount of an
oxidizing agent to silicone oil, the vacuum ultraviolet light that passed the silicone oil layer was made fluoresce in the
phosphor to monitor the progress of the photo-oxidation reaction. As the vitrification by photo-oxidation reaction of
the silicone oil layer improved, the fluorescence intensity of the phosphor increased. While monitoring the change of the
fluorescence intensity, the supply of the oxidizing agent and the irradiation time of the vacuum ultraviolet light were
controlled; as a result, the new method to efficiently form a transparent, photo-oxidized thin film has been established.
A transparent low refractive index SiO2 film was laminated on a glass substrate with photochemical reaction by an Xe2* excimer lamp in the presence or NF3, 02 and silicon wafer at room temperature. The glass substrate and the silicon wafer were placed in the reaction chamber, which was filled with NF3 and O2 gases in the mixing ratio of 10:1 and under 330 Torr. The Xe2* excimer lamp was, then, irradiated for 20 minutes. The SiO2 film was spontaneously laminated on the glass substrate by repeating an adsorption of SiF4 and a photochemical oxidization with NO2, which was photo-dissociated from a mixed gas of NF3 and O2. The film thickness was 160 nm and the infrared spectrum was measured; the Si-O peaks were depicted at 600, 700, 1100[1/cm-1]. And Si-F peak was observed at 740[1/cm-1]. Then, the refractive index of the SiO2 film was 1.36. After annealing the film for one hour at 200 degree, the refractive index increased to 1.42.
