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.
There is the method to form microscopic roughness on the surface of a sample in order that a film or adhesive is hard to
peel off, but it is unsuitable to optical material surfaces. We, thus, demonstrated the undamaged surface of the optical
material on which the coating agent or adhesive was applied by chemically incorporating the functional groups. Many
thin films are deposited, but most of them come off if wiped. Then, hydrophilic groups (-OH) were incorporated on the
sample surface beforehand, and photo-adhesion or coating was carried out. The sample surface was firstly treated by
discharge plasma for promoting efficiency of hydroxyl group substitution, and hydroxyl groups were incorporated on the
modified side in water ambient when the material temporarily maintained high wettability; as a result, the adhesion or
coating and the modified side were united persistently. The contact angle with water of fused silica is 40 degrees; that
of sapphire is 72 degrees; that of BK7 glass is 31 degrees. When those surfaces were irradiated by glow discharge
plasma of DC pole sputtering system for five minutes, all of the surfaces dropped to five degrees. Under this condition,
silicone oil was applied on each pretreated sample surface and irradiated with excimer lamp light (172nm) for 60 minutes.
The adhesive strength of the silica glass plates with plasma pretreatment improved to 25M pascal when compared with
that of the silica glass plates without pretreatment, which was 18M paschal.
The organic silicone oil applied over the surface of a fused silica glass or Kaliumdihydrogenphosphat (KDP) nonlinear
optical crystal was changed to an inorganic glass by the photochemical oxidization using a Xe2 excimer lamp in the air.
As a result, the thin film acquired a characteristic of high power laser tolerance equivalent to quartz. Dimethylsiloxane
silicone oil was spin-coated on the surfaces of a fused silica substrate and KDP to form a film of 100-nm thickness;
which were irradiated with the Xe2
excimer lamp light (wavelength 172 nm, power density 10 mW/cm2) for 60 minutes
in oxygen atmosphere. The films were further irradiated with the Nd: YAG laser of ω (1.06 μm) or 2ω (0.503 μm), and
the laser damage test (J/cm2/10 ns) was conducted. The laser damage threshold of the photo-oxidized 100 nm thick
film formed on the fused silica substrate was 72 J/cm2 in ω and 107 J/cm2 in 2ω. On the KDP substrate, the laser
damage threshold of the thin film was 32.4J/cm2 in ω and 32.6 J/cm2 in 2ω.
An adhesive method that creates properties of heatproof, waterproof, and transparent to ultraviolet ray of 200 nm and
under in the wavelength without adhesive strain was developed by putting one silica glass to another with the silicone oil
that had been photo-oxidized by Xe2 excimer lamp. The measurement by the ZYGO interferometer showed that there
was neither adhesive strain nor bubbles, and the bonding strength of 18MPa was achieved. To compare the heat
resistance of the photo-oxidized silicone oil with that of general-purpose adhesives such as silicone rubber, water glass,
and epoxy resin, the shearing tensile strength test was conducted after exposing at high temperatures from 25 to 500 °C.
As a result, the silicone rubber adhesive exfoliated at 110 °C, and the epoxy resin adhesive, at 150 °C; however, the
photo-oxidized silicone oil had the bonding strength of 6.5MPa at 500 °C.
Using photo-excited silicone oil developed a new protective hard coating method for high power laser to present the tolerance in water. The silicone oil was spin-coated onto the surface of an optical material and then irradiated with a xenon excimer lamp in the air, which transformed the organic silicone oil into inorganic glass. This technique has enabled an optical thin film capable of transmitting ultraviolet rays of wavelengths under 200 nm and possessing the characteristics of homogeneity, high density, resistance to environmental effects and to water, anti-reflective in water, and Mohs scale value of 5.
The dot patterned hydrophilic and hydrophobic groups were photo-chemically substituted in minute pattern on the polymethylmethacrylate [PMMA] intraocular lens [IOL] by the Xe2 excimer lamp and the ArF excimer laser; consequently, the IOL that is free from fibrin has been developed.
PMMA has been used as an intraocular lens IOL because of its high transmittance in the visible region and superb mechanical modifiability. However, protein and fat are stuck onto the lens surface after a long-term insertion, where cells proliferate; which causes the surface to get opaque, namely after-cataract.
Firstly, the IOL was irradiated with Xe2 excimer lamp in the presence of perfluoropolyether [PFPE] to be hydrophobic. By the photochemical reaction, the CF3 functional groups were substituted on the IOL surface. In order to substitute hydrophilic groups in matrix-form on the surface, the ArF laser light was then irradiated on the hydrophobic surface in the presence of water through the 50mm f dot-patterned negative mask and the lens to project the reduced pattern. With this selective photochemical surface modification, the hydrophilic and hydrophobic groups were arrayed alternately on the sample surface. The modified IOL was soaked in fibrin [FIB] water solution, and the fibrin-sticking rate was measured by infrared spectroscopy [FT-IR]. The lower fibrin-sticking rate of the IOL surface was achieved by the hydrophobic and hydrophilic micro domain structures. Furthermore, it was confirmed that the fibrin-sticking rate decreased as the OH group interval was narrowed. The modified surface with the 20 mm f domains with hydrophilic and hydrophobic was lowest in fibrin sticking.
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.
The new, strong adhesion method has been developed for optical materials to transmit vacuum ultraviolet rays by using silicone oil. Silicone oil (dimethyl siloxane) has the main chain of siloxane bonds like quartz and the side chains of methyl group. By irradiating ultraviolet rays in oxygen atmosphere, the organic silicone oil was photo-oxidized and changed into inorganic glass. The silicone oil was poured into the thin gap between two pieces of silica glass in oxygen atmosphere and irradiated with the Xe2 excimer lamp. Consequently, the siloxane of the silicone oil was bonded with the O atoms that had been absorbed on the glass surface to form SiO2. The UV transmittance of the silicone oil was
improved by 62%, from 30% before the lamp irradiation to 92% after the 60-minute irradiation. Furthermore, the adhesive strength of the silicone oil was enhanced from 0 kgf/cm2 before the irradiation to 180 kgf/cm2 after the irradiation. The honeycomb structure board and plane mirrors were adhered with the Xe2 excimer lamplight and photo-oxidized silicone oil.
Having substituted the hydrophilic and hydrophobic groups alternately on the soft acrylic resin intraocular lens (IOL) surface by using an ArF excimer laser and a Xe2 excimer lamp, we have developed the IOL that is free from fibrin. Acrylic resin or PMMA lens has been used as an intraocular lens for 50 years. However, protein and fat are stuck onto the IOL surface after a long implantation, which opacifies the surface (after-cataract). Thus, we designed the micro domain structures of hydrophilic and hydrophobic groups on the IOL surface for fibrin-free. Firstly, the IOL was irradiated with the Xe2 excimer lamp in the presence of perfluoropolyether in order to make it hydrophobic. By this photochemical reaction, the CF3 functional groups were substituted on the IOL surface. Secondly, the ArF laser was projected on the IOL through the mask pattern in reduced size in the presence of water in order to be hydrophilic. With the photochemical reaction, the OH groups were substituted at the part exposed. The fibrin adsorption test of the modified IOL surface was carried out with FT-IR; which revealed that the fibrin-sticking rate of the treated sample has decreased by 23% compared with that of the non-treated sample. As a result, the fibrin-free IOL has been made by modifying the surface of the IOL to have the micro domain structures of the hydrophilic and hydrophobic groups that are arrayed alternately. In conclusion, the ideal intraocular lens has been demonstrated.
Si wafer was polished accurately with ArF laser irradiation in the presence of the hydrofluoric acid water solution. The highest surface accuracy of Si wafer is needed for the Si substrate for using extremely ultra violet (EUV) lithography. Then we tried to polish the SiO2 with hydrofluoric acid water solution, which was photo-oxidized Si wafer surface with active oxygen. The active oxygen was photo-dissociated from water (H2O). The Si wafer surface was pressurized at 50g/cm2 on the fluorocarbon-polishing mat. Next the hydrofluoric acid water solution is infiltrated into the thin gap between the sample and the fluorocarbon. And ArF laser is irradiated through the fluorocarbon turntable. By this irradiation, the Si wafer surface was oxidized and produced SiO2. The moment it is dissolved by HF solution. After the etching, the polishing progresses by the friction with the fluorocarbon. The surface roughness was obtained 3 nm with 30 minute polishing with the ArF laser irradiation (20 mJ/cm2, 100 pps) in 15% HF/H2O ambience.
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.
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.
SiC surface was polished accurately with KrF laser irradiation in the presence of the HF and H2O2 mixed solutions. The SiC is very hard; moreover, the material is resistant to chemicals. Then we tried to polish the softened SiC chemically on the soft mat. The SiC surface was pressurized at 50 g/cm2 on the fluorocarbon polishing mat. Next the HF and H2O2 mixed solutions are infiltrated into the thin gap between the sample and the fluorocarbon, and KrF laser irradiated through the fluorocarbon turntable. By this irradiation, the SiC surface was oxidized and produced SiO2 and CO2. Then CO2 is diffused in an atmosphere, and only SiO2 solidified on the sample surface. The moment the SiO2 was formed, it dissolves in HF solution. After the etching, the polishing progresses by the friction with the fluorocarbon. The surface roughness was obtained 80 nm with 60 minute polishing with KrF laser irradiation (400 mJ/cm2, 20 pps) in 15% HF/H2O2 ambience.
Intractable glaucoma results from hindrances in the eyeball aqueous humor pathways that increase the intraocular pressure above normal physiological levels (over 20 mmHg). In this study porous PTFE membranes were made hydrophilic with a photochemical method that use ethyl alcohol and water for the chemical solution.
Polishing of fused silica micro optics was demonstrated without polishing dummy by using an ArF excimer laser and water solution. A fused silica glass sample was placed on the fluorocarbon grinding turntable. And the water solution was poured into a thin gap between the sample and fluorocarbon surface by capillary phenomenon. And a patterned ArF excimer laser light was irradiated on the fluorocarbon surface through the fused silica sample surface at the laser fluence of 15 mJ/cm2. By this photo irradiation, the water and fluorocarbon surface were photo- dissociated and produced hydrofluoric acid locally. By the hydrofluoric acid, the silica glass surface which were contacted with the hydrofluoric acid and fluorocarbon surface was etched. As a result, the only photo irradiated part of the silica glass sample was polished effectively.
Polymethyl methacrylate (PMMA) surface was photochemically modified in open air by using an ArF excimer laser and an ammonia-water solution. Photo-excited C-H bonds of the surface were effectively dehydrogenated with hydrogen atoms which were photodissociated from the ammonia-water solution. The dangling bonds of the dehydrogenated carbon atoms were combined with the NH2 and OH radicals which were also photodissociated. Thus, the sample surface showed hydrophilic property only on the photomodified parts. Based on the photomodification technique, a commercial hard-contact lens was also photomodified for tear affinity.
A tough adhesivity of teflon and stainless steel using an epoxy resin-based bonding agent was performed. The chemical stability of teflon is attributed to the C-F bond composed. Thus, it is considered to pull out the fluorine atoms selectively from the area irradiated with an ArF excimer laser light and to substitute a functional group displaying excellent affinity with bonding agents to create a powerful adhesivity. The defluorination of the surface was performed with boron atoms which were photodissociated from orthoboric acid water solution. The hydroxyl groups, which have a good affinity with epoxy bonding agent, were substituted only at area exposed to the laser light. The modified teflon surface with the epoxy bonding agent, and shearing tensile strength were performed. The strength was 110 Kgf/cm2.
A powerful adhesion of fluororesin (Teflon) featuring its excellent corrosion resistance and stainless steel was performed by using an epoxy resin-based bonding agent. Adhesion strength was 500 times more than that of untreated teflon, which has virtually no affinity with chemicals and solids. The teflon surface was irradiated by an ArF excimer laser light with energy higher than the carbon-fluorine bond, in a tetrahydroborate (BNaH4) and methyl alcohol (CH3OH) mixed solution ambient. The defluorination of the surface was performed with the boron atoms which were photodissociated from BNaH4. The fluorine atoms of the surface was replaced with the CH3 and OH radicals, also photo dissociated from CH3OH. The methyl(-CH3) and hydroxyl(-OH) groups, which have a good affinity with epoxy bonding agent, were substituted only for the area exposed to the laser light. The modified teflon surface was adhered to a stainless steel with the epoxy bonding agent, and shearing tensile strength test was performed. The strength was 100 Kgf/cm2, whereas untreated teflon's strength is 0.2 Kgf/cm2 or less. Thus the adhesion was improved considerably.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.