Gamagōri, Japan
Gamagōri, Japan

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Patent
Itoh Optical Industrial Co. and Koito Manufacturing Co. | Date: 2012-06-06

An automotive lamp includes an LED, a substrate that mounts the LED, a reflector that reflects the light emitted from the LED, and an projection lens having an incident surface, which receives the light reflected by the reflector, and an emission surface that emits the light toward a front area of the automotive lamp. A fine asperity structure is formed on the incident surface of the projection lens. The fine asperity structure includes recesses or raised portions formed with the pitch less than or equal to the visible light wavelength.


Mutoh K.,Aoyama Gakuin University | Nakagawa Y.,Itoh Optical Industrial Co. | Hatano S.,Hiroshima University | Kobayashi Y.,Aoyama Gakuin University | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2015

Biradicaloid species have been extensively studied for their characteristic features in electric conductivity, magnetism, and optical nonlinearity. Theoretical investigations of rigid biradicaloid species have been suggesting that they are represented as a resonance hybrid of open-shell biradical and closed-shell quinoid structures. However, much is still unknown about flexible biradicaloid species whether the activation free energy barrier between these states exists or not. Herein, we investigated the thermal isomerization from the photogenerated unstable biradical to the stable quinoid species observed for the photochromic dimer of a bisimidazolyl radical and found that the large negative activation entropy for the valence isomerization causes the activation free energy barrier between these two states. © the Owner Societies 2015.


Kurihara K.,Japan National Institute of Advanced Industrial Science and Technology | Saitou Y.,Itoh Optical Industrial Co. | Souma N.,Tokai Seimitsu Industrial Co. | Makihara S.,Tokai Seimitsu Industrial Co. | And 2 more authors.
Materials Research Express | Year: 2015

We provide a lens mould to attain an anti-reflection sub-wavelength structure (SWS) for plastic replica in the injection moulding process. To obtain the SWS on the lens mould, platinum nanoparticles formed by decomposition of a platinum oxide were employed. The fabricated platinum nanoparticles were estimated to be 90 nmin diameter, on average, and the dispersion of the particle diameter was evaluated to be ±20 nm. Through nanostructure replication by injection moulding, antireflection of less than 0.5% was achieved, and transmittance increased over 98%. In addition, a high-replication durability of over 10 000 times was attained. The variation of the minimum reflection ratio was evaluated to be 0.38% ± 0.04%. The usefulness of the proposed SWS mould for mass-production was confirmed, as it allows for high durability and SWS formation on the lens surface. © 2015 IOP Publishing Ltd.


Kaarna A.,Lappeenranta University of Technology | Nishino K.,Toyohashi University of Technology | Miyazawa K.,Itoh Optical Industrial Co. | Nakauchi S.,Toyohashi University of Technology
Color Research and Application | Year: 2010

A michromatic (microscope plus chromatic) scope is a device that enhances the color discrimination between two spectral color datasets. Three spectral filters are required, instead of the conventional red, green, and blue filters, for the implementation of a michromatic camera. In this study, we describe two approaches to the design of these filters: in the first case, the design is based on the direct optimization of the filter characteristics (transmittance), whereas in the second case, the design is based on the nonnegative tensor factorization (NTF) of the spectral datasets. A michromatic camera can be implemented using these filters along with compatible postprocessing in-camera firmware. Here, we performed experiments with two color datasets: one comprising skin and vein colors, and one comprising skin and cosmetics colors. These were further divided into a training set and a test set. The filters were defined using the training set, and the operation of the filters was tested and magnified using the test set. Our experiments demonstrated that the proposed approaches are suitable for color discrimination. For the first color dataset, the enhancement produced using the optimized filters was up to 252% of the original value, and the average color difference ΔE was increased from 2.82 to 9.93. NTF and preprocessing further enhanced the ΔE up to 21.84. For the second color dataset, NTF and postprocessing enhanced the ΔE from 4.33 to 29.19. The proposed discrimination enhancement could be physically implemented in a designated digital charge-coupled device camera with proper filter installation and compatible postprocessing. © 2010 Wiley Periodicals, Inc. Col Res Appl, 35, 101-109, 2010; Published online 7 January 2010 in Wiley InterScience (www.interscience.wiley.com).


Mutoh K.,Aoyama Gakuin University | Nakagawa Y.,Itoh Optical Industrial Co. | Sakamoto A.,Aoyama Gakuin University | Kobayashi Y.,Aoyama Gakuin University | And 2 more authors.
Journal of the American Chemical Society | Year: 2015

Stepwise two-photon processes not only have great potential for efficient light harvesting but also can provide valuable insights into novel photochemical sciences. Here we have designed a [2.2]paracyclophane-bridged bis(imidazole dimer), a molecule that is composed of two photochromic units and absorbs two photons in a stepwise manner. The absorption of the first photon leads to the formation of a short-lived biradical species (half-life = 88 ms at 298 K), while the absorption of the additional photon by the biradical species triggers a subsequent photochromic reaction to afford a long-lived quinoid species. The short-lived biradical species and the long-lived quinoid species display significantly different absorption spectra and rates of the thermal back-reaction. The stepwise two-photon excitation process in this photochromic system can be initiated even by incoherent continuous-wave light irradiation, indicating that this two-photon reaction is highly efficient. Our molecule based on the bridged bis(imidazole dimer) unit should be a good candidate for multiphoton-gated optical materials. © 2015 American Chemical Society.


Patent
Itoh Optical Industrial Co. | Date: 2014-03-26

The present invention relates to an optical element which comprises a multi-layer antireflective film (optical inorganic thin film) (16) on an optical element substrate (10). A first layer (starting from the closest side to the optical element substrate: the same shall apply hereafter.) of the optical inorganic thin film is a vapor-deposited film (hereinafter called specified vapor-deposited film) composed of either 1) a mixture or compound of La oxide and Ti oxide, or 2) a mixture or compound of La oxide and Ta oxide and shows a refractive index n_(D)=1.95-2.25. In addition, a final layer is to be a vapor-deposited film comprising SiO_(2), and a middle layer composed of a single or multi-layered vapor-deposited film which comprises one metal oxide selected from a group consisting of ITO (indium tin oxide) and oxides of Group 4 and 5 elements in the fourth to sixth periods is included in the inner side of the final layer. This optical element hardly develops initial swelling while a high degree of heat resistance is maintained.


Patent
Itoh Optical Industrial Co. | Date: 2015-01-28

Provided is a hard coating composition with which optical interference and a blue discoloration due to ultraviolet rays do not occur when applied to an ultrahigh refractive index organic glass with a refractive index exceeding 1.67. The hard coating composition is applied to an optical component body formed of an organic glass. An alkoxysilane hydrolyzate is a hydrolyzate of a mixture of a predetermined ratio of a trialkoxysilane and a tetraalkoxysilane, and an inorganic oxide colloid is blended to make a coating film refractive index approximate to the refractive index of the organic glass. The inorganic oxide colloid is a rutile-based colloid containing an amine dispersant. An organic carboxylic acid is used as a low-temperature curing catalyst of the hydrolyzate.


Patent
Sumitomo Chemical, Japan National Institute of Advanced Industrial Science, Technology and Itoh Optical Industrial Co. | Date: 2012-02-08

Provided is a methacrylic resin composition to be used for molding by means of a metallic mold having a plurality of nano-scale concavo-convex patterns on the surface thereof. The methacrylic resin composition comprises a methacrylic resin (A) having an MFR at 230C under a load of 3.8 kg within the range of 0.1 to 50; and at least one component (B) selected from the group consisting of higher fatty acid esters, higher aliphatic alcohols, higher fatty acids, higher fatty acid amides, and higher fatty acid metal salts, wherein the content of the component (B) is 0.2 to 0.5 parts by weight with respect to 100 parts by weight of the methacrylic resin (A).


Patent
Itoh Optical Industrial Co. | Date: 2013-07-22

Provided is a hard coating composition with which optical interference and a blue discoloration due to ultraviolet rays do not occur when applied to an ultrahigh refractive index organic glass with a refractive index exceeding 1.67. The hard coating composition is applied to an optical component body formed of an organic glass. An alkoxysilane hydrolyzate is a hydrolyzate of a mixture of a predetermined ratio of a trialkoxysilane and a tetraalkoxysilane, and an inorganic oxide colloid is blended to make a coating film refractive index approximate to the refractive index of the organic glass. The inorganic oxide colloid is a rutile-based colloid containing an amine dispersant. An organic carboxylic acid is used as a low-temperature curing catalyst of the hydrolyzate.


PubMed | Itoh Optical Industrial Co. and Aoyama Gakuin University
Type: Journal Article | Journal: Journal of the American Chemical Society | Year: 2015

Stepwise two-photon processes not only have great potential for efficient light harvesting but also can provide valuable insights into novel photochemical sciences. Here we have designed a [2.2]paracyclophane-bridged bis(imidazole dimer), a molecule that is composed of two photochromic units and absorbs two photons in a stepwise manner. The absorption of the first photon leads to the formation of a short-lived biradical species (half-life = 88 ms at 298 K), while the absorption of the additional photon by the biradical species triggers a subsequent photochromic reaction to afford a long-lived quinoid species. The short-lived biradical species and the long-lived quinoid species display significantly different absorption spectra and rates of the thermal back-reaction. The stepwise two-photon excitation process in this photochromic system can be initiated even by incoherent continuous-wave light irradiation, indicating that this two-photon reaction is highly efficient. Our molecule based on the bridged bis(imidazole dimer) unit should be a good candidate for multiphoton-gated optical materials.

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