168 results about "Photoelasticity" patented technology

An optical compensation film comprising a cellulose ester film is disclosed. In the film, (a) each of photoelastic coefficient C(md) in a mechanical direction and photoelastic coefficient C(td) in the transverse direction of the cellulose ester film is 1×10−9 to 1×10−13 Pa−1 and C(md)<C(td), (b) retardation R0 within the plane of the cellulose film defined by Formula (I) is 20 to 70 nm, (c) retardation Rt of the cellulose ester film in a thickness direction, defined by Formula (II) is 70 to 400 nm, and (d) both of a dimensional variation ratio S(md) in the mechanical direction and a dimensional variation ratio S(td) in the transverse direction of the cellulose ester film prior to and after being allowed to stand at ambient conditions of 80° C. and 90 percent relative humidity for 50 hours are −1 to 1 percent, and |S(md)|>|S(td)|.

An optical glass, having a refractive index nd which is greater than 1.59, an abbe number υd which is greater than 67, a low photoelastic coefficient and good chemical stability and grinding performance. The fluorophosphate optical glass contains, by cation percentage contents: P5+: 30％-40％, Al3+: 12％-20％, Ba2+: 30％-40％, Ca2+: 1.3％-12％, Sr2+: 1％-10％, La3+: 0％-5％, Gd3+: 0％-6％, Y3+: 0％-10％ and contains, by anion percentage contents: F+: 25%-40％, O2-: 60%-75％. The optical glass is applicable to manufacturing methods such as precision moulding, secondary hot-press forming and cold processing, and to manufacturing optical elements such as a high-performance spherical, aspheric and planar lens and a prism and an optical grating.

There is provided a retardation film including a stretched film of a polymer film having an absolute value of photoelastic coefficient (m2 / N) of 50×10−12 or less measured by using light of a wavelength of 550 nm at 23° C., which satisfies the following expressions (1) and (2):Re[450]<Re[550]<Re[650]  (1)Rth[550]<Re[550]  (2).In the expressions (1) and (2): Re[450], Re[550], and Re[650] respectively represent in-plane retardation values measured by using light of wavelengths of 450 nm, 550 nm, and 650 nm at 23° C.; and Rth[550] represents a thickness direction retardation value measured by using light of a wavelength of 550 nm at 23° C.

The utility model discloses a measuring method and a measuring device of elastohydrodynamic lubrication line contact pressure based on photoelasticity. According to the measuring method of the elastohydrodynamic lubrication line contact pressure based on the photoelasticity, a friction test sample of elastohydrodynamic lubrication is made of transparent photoelasticity materials, a friction area is irradiated by polarized light, the friction area is observed in an amplified mode through a microscope in the direction of a light source after a polarizing film is detected, photoelasticity strips appear in a friction pair in the contact area irradiated by the polarized light, oil film pressure in the contact area can be displayed and measured in real time after calculating and marking, and resolution ratio of the pressure is determined by the amplification ability of the microscope which is used and the resolution ratio of a camera. The measuring device of the elastohydrodynamic lubrication line contact pressure based on the photoelasticity comprises a collimation light source, a polarizer, the friction contact area, an analyzer, a stereoscopic microscope and an imaging recording device in sequence in the light path direction. According to the measuring method and the measuring device of the elastohydrodynamic lubrication line contact pressure based on the photoelasticity, distribution of pressure in the elastohydrodynamic lubrication line contact area can be measured with high resolution ratio and in real time.

The invention discloses a method for processing stress-fringe-order numerical values of a photoelastic model. The method comprises the following steps that (1) part of a rotating photoelastic model test piece is selected, and a manufacturing method same as the method for manufacturing the photoelastic model is used for manufacturing an auxiliary photoelastic model; (2) rotating centrifugal force acting on the auxiliary photoelastic model is converted into tension, and the auxiliary photoelastic model is subjected to classified increment freezing loading; (3) test data of stress-fringe-order numerical values of the auxiliary photoelastic model subjected to classified increment freezing loading are acquired, and are subjected to curve fitting; (4) the stress-fringe-order numerical values of the photoelastic model are corrected by using fitting data variables. The stress-fringe-order numerical values of the photoelastic model obtained through the method are more close to the real stress level.

Provided are a stress analysis method and stress analysis equipment that enable a detailed stress measurement, by using both a photoelasticity measurement method and a stress measurement (mechanoluminescence measurement) which utilizes a mechanoluminescent substance to measure a stress state of an object. Physical quantities that are measurable include individual principal stress component and a principal stress direction. The photoelasticity measurement method alone cannot measure individual principal stress component values.

The invention provides an optical film which is capable of suppressing the coloring of display image even when the display image is viewed obliquely with respect to the normal direction of a screen and is capable of displaying an image having minimized gradation reversed region, and is excellent in durability. The multilayer optical film is constituted by laminating: an optical film (1) which is obtained by stretching a polymer film comprising polycarbonate base resin and styrene type resin, has an absolute value of photoelasticity coefficient of 2.0x10<-11> to 6.0x10<-11> m<2> / N and has controlled three-dimensional refractive index so as to obtain the Nz coefficient satisfying Nz <= 0.9 and the front retardation satisfying Re >= 80 nm; an optical film (2) showing an optically positive uniaxial property; and an optical film (3) made of a material showing an optically negative uniaxial property, comprising a part in which the material is obliquely aligned, and having a thickness of 30 to 90 mum.

A laminated optical film comprising an optical film(1) obtained by stretching a polymer film comprising a polycarbonate resin and a styrene resin, wherein a photoelastic coefficient is 2.0 x 10<-11> to 6.0 x 10<-11>m<2> / N, and a three dimensional refractive index is controlled, an optical film (2) showing optically positive uniaxial property that satisfies a relationship of nx2 > ny2 SIMILAR nz2, and an optical film (3) formed of a material showing optically negative uniaxial property, and the material being tilting aligned; enables inhibition of coloring of display image for observation of a display picture in a diagonal direction to normal line of a screen, and enables display of an image having little gradation inversion areas, and that has outstanding durability.

An optical film having a desired wavelength dispersion characteristic, a low photoelastic coefficient and a desired Nz coefficient.The optical film is formed from a copolymer and meets the following conditions (i) to (v):(i) the thickness (d) is 20 to 80 μm;(ii) the following formulas (1) and (2) are satisfied:0.6<R(450) / R(550)<1  (1)1.01<R(650) / R(550)<1.40  (2)(R(450), R(550) and R(650) are retardations within the plane of the film at respective wavelengths);(iii) R(550) is 120 to 160 nm;(iv) the birefringence (Δn) is not less than 1.5×10−3; and(v) the Nz coefficient represented by the following formula (4) is 1.18 to 2.40:Nz=(nx−nz) / (nx−ny)  (4)(nx, ny and nz are 3-dimensional birefringences of the film).

The thermoplastic resin composition of the present invention comprises (A) a cycloolefin-based polymer and (B) a vinyl-based polymer having a polar group, has a glass transition temperature of not lower than 100° C. and has a difference in glass transition temperature between the polymers (A) and (B) of less than 50° C. The optical film of the present invention comprises the thermoplastic resin composition of the invention. According to the present invention, it is possible to improve development of retardation at a low stress in the film stretching while retaining excellent heat resistance and optical properties and maintaining wavelength dispersion properties. The optical film of the invention exhibits properties that the dependence of retardation of a transmitted light on wavelength, said retardation being obtained by stretch orientation of the film, becomes larger as the wavelength becomes longer (positive wavelength dispersion properties), has low water absorption and low coefficient of photoelasticity, and is excellent in adhesion or bonding properties to other materials.

A variety of toy polariscopes are simpler in design and less costly than precision instruments used in scientific research and stress analysis of materials and structures. The toy polariscopes are designed for a variety of objects that may exhibit photoelastic properties such as glass, plastic, Plexiglas, gel candle material and other gels, and even edible photoelastic objects. They are specially designed for objects of various sizes with a variety of purposes such as objects to enhance learning in a variety of conditions and experiences. Special objects are designed to go with the toy polariscopes such as edible and inedible photoelastic objects, photoelastic candle material, a variety of photoelastic / photoplastic stands capable of a variety of displays in interaction with other designed photoelastic objects capable of a variety of interaction and displays. Other optical phenomena may also be observed.

A GaN single crystal substrate has a main surface with an area of not less than 10 cm2, the main surface has a plane orientation inclined by not less than 65° and not more than 85° with respect to one of a (0001) plane and a (000-1) plane, and the substrate has at least one of a substantially uniform distribution of a carrier concentration in the main surface, a substantially uniform distribution of a dislocation density in the main surface, and a photoelasticity distortion value of not more than 5×10−5, the photoelasticity distortion value being measured by photoelasticity at an arbitrary point in the main surface when light is applied perpendicularly to the main surface at an ambient temperature of 25° C. Thus, the GaN single crystal substrate suitable for manufacture of a GaN-based semiconductor device having a small variation of characteristics can be obtained.