158 results about "Photoelasticity" patented technology

An optical material having a high birefringence and a small absolute value of a photoelastic coefficient is provided by use of a resin composition for an optical material comprising a resin (a) having a positive photoelastic coefficient and a negative inherent birefringence and a resin (b) having a negative photoelastic coefficient and a negative inherent birefringence.

A plastic molded article laminated a layer with a photochromic property and/or a layer with a polarization property on at least one side of a base material, said base material being a polycarbonate having a photoelastic constant of 55×10⁻¹² m²/N or below.

A detection system for measuring glass that has been placed under strain and the resulting stress lines in the glass has a light source of individual elements configured to create a light distribution. The light distribution has a discontinuity which enhances the viewing of a photoelastic effect in the glass. The light source creates a viewable optical interference (i.e., color changes) which results from stress lines in the glass.

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 relates to a stress measuring method based on a dynamic photoelastic system. The method comprises that dark-field imaging is carried out, and a first light intensity value of a stress measuring point is obtained; bright field imaging is carried out, and a second light intensity value of the stress measuring point is obtained; dark compensation field imaging is carried out to obtain a third light intensity value of the stress measuring point; the phase difference of birefringence caused by stress is obtained on the basis of the first, second and third light intensity values; and on the basis of the phase difference, different stress values of the stress measuring point are calculated. A laser vibration meter is used to verify the accuracy of a result measured via the method; the measuring method which is a new rotation polarizer method is characterized by a simple optical system, simple operation and the accurate result; and the measuring method can serve as a brand new method to measure the internal stress of a transparent solid, and can be applied to small stress measurement.

It is an object of the present invention to provide an optical film which has reverse chromatic dispersibility that its retardation becomes smaller as the wavelength becomes shorter and a low photoelastic constant.

The optical film is made of a polycarbonate copolymer containing a unit (A) represented by the following formula:

and a unit (B) represented by the following formula:

the (A/B) molar ratio of the unit (A) to the unit (B) is 10/90 to 90/10 and which satisfies the following expression (1):

R(450)<R(550)<R(650)  (1)

• • wherein R(450), R(550) and R(650) are retardation values within the plane of the film at wavelengths of 450 nm, 550 nm and 650 nm, respectively.

The invention relates to a vacuum casting process method of a photoelastic model. A vacuum casting forming machine and a silicon rubber female mold arranged in the vacuum casting forming machine are used for casting forming, the automation degree is high, the errors are few, and in addition, the harm to human bodies by harmful gas released in the casting process because of artificial participation is avoided. The process comprises the following steps that: step 1, epoxy resin 128 and succnic acid are respectively weighed according to the weight proportion being 100:30-35 in accordance with the photoelastic model to be cast, in addition, the epoxy resin 128 and the succnic acid are uniformly mixed under the vacuum condition of a vacuum stirring temperature control room, the purity of raw materials is improved, and the nonuniformity of materials is avoided; step 2, after a forming chamber of the model is subjected to vacuum pumping, the poxy resin 128 and the succnic acid uniformly mixed in the step 1 are filled into the silicon rubber female mold, and the casting forming is carried out; and step 3, the photoelastic model after the cast forming is solidified.

The object of this invention is to provide an optical film formed of a copolycarbonate having a desired chromatic dispersion and low photoelasticity and having excellent melt processability.

The optical film comprises a copolycarbonate composed of 25 to 90 mol % of unit (A) of the following formula,

and 10 to 75 mol % of unit (B) of the following formula,

R(450)<R(550)<R(650)  (1)

• • wherein R(450), R(550) and R(650) are in-plane retardation values of the film at wavelengths of 450 nm, 550 nm and 650 nm.

A polarizing plate with an optical compensation layer capable of appropriately preventing leakage of light in black display while preventing thermal unevenness and contributing to reduction in thickness, and an image display employing it. The polarizing plate with an optical compensation layer comprises a polarizer, a first optical compensation layer, a second optical compensation layer, and a third optical compensation layer arranged in this order. The first, second and third optical compensation layers respectively have a predetermined absolute value of photoelastic coefficient, refractive index distribution, in-plane phase difference and/or phase difference in the thickness direction, respectively. The angle between the absorption axis of the polarizer and the lag axis of the first optical compensation layer is 10-30 DEG, the angle between the absorption axis of the polarizer and the lag axis of the second optical compensation layer is 70-95 DEG, and the angle between the absorption axis of the polarizer and the lag axis of the third optical compensation layer is 70-95 DEG.

The invention provides a full-court shearing stress automatic determining method in digital photoelasticity, belonging to a photoelectricity non-destructive test field, comprising: laying the detected photoelasticity body in a photoelastical gauge to apply load, and adjusting the optical field being orthogonal plane polarization field under the white light incidence and respectively collecting four phase shift images when an analyser and a polarizer synchronistically rotate to 0, Pi/8, Pi/4 and 3Pi/8; obtaining the phase diagram of first major principal stress (-Pi/2,Pi/2) using four step color phase-shift method; adjusting the optical field being orthogonal circular polarization field user homogeneous light incidence and collecting six phase shift images when the analyser and the second 1/4 wave plate respectively rotate to (Pi/4,0), (3Pi/4,0), (0,0), (Pi/4,Pi/4), (Pi/2,Pi/2) and (3Pi/4,3Pi/4); combining the phase diagram of first major principal stress and using the improved six phase shift method to obtain isochromatic line packing phase diagram without 'distortion' and performing packing and calculating the full-court shearing stress. The full-court shearing stress can be automatically calculated and the work efficiency is increased and the complicated work of manually data collecting and processing is prevented.

An object of the present invention is to provide a resin material capable of producing a molded body having few defects due to foreign substances, having high mechanical strength, very small in both orientation birefringence and photoelastic birefringence, and having high transparency, and having high transparency even when such a resin material is stretched. Provided is a resin composition containing a resin (A) and a multilayer structure polymer (B), wherein the multilayer structure polymer (B) has a crosslinked polymer layer and a hard polymer layer, and the hard polymer layer has at least two different hard polymer layers, at least one of which is a hard polymer layer (C) opposite in sign of a photoelastic constant to that of the resin (A).

The invention discloses a computer-to-plate flexible plate and a production method thereof. The flexible plate comprises a supporting body, a photosensitive elastomer layer, an anti-adhering layer and a protection film, a plate material is directly scanned through a computer and then cleaned with water or a solution prior to being dried in hot wind to be made into a printing plate of the flexible plate, scanning of the computer is performed before stripping of the protecting film or after stripping of the protecting film, the photosensitive elastomer layer is highly sensitive to purple light and ultra violet and can be sufficiently cross-linked and solidified; the protecting film is a transparent thin film. Dynamic integration of rapid laser plate production and fine network reduction is realized, and adhesive strength of the photosensitive elastomer layer of the flexible plate is good.

The invention discloses a method for improving a rotation stress stripe level value of an epoxy resin photoelastic model. The method comprises the following steps: selecting local characteristics needing to be researched of a rotation test piece; designing and preparing an epoxy resin photoelastic model according to the local characteristics of the selected rotary test piece; installing a plurality of epoxy resin photoelastic models on a rotating disc according to a set rotating radius and layout, and freezing the epoxy resin photoelastic models; slicing the frozen epoxy resin photoelastic models, and reading the stress stripe levels of the epoxy resin photoelastic models. According to the invention, the real working conditions of parts are better simulated, the parts are closer to load similarity, the similarity principle is satisfied, the test precision is improved, the rotation photoelastic test of multiple local characteristics is carried out at the same time, and the test cost canbe greatly reduced.

The invention provides a K-K-coherent-reception-based modulation format recognition method. The method comprises: S1, determining an output wavelength and a power of a local oscillator laser device; and S2, restoring a signal constellation point by using K-K coherent reception and a corresponding channel damage compensation algorithm and determining a corresponding modulation format. The K-K-coherent-reception-based modulation format recognition method can be applied to blind detection of a single polarization signal modulation format type in a new-generation optical elastic network. On the one hand, only one PD is needed to complete signal reception; and compared with the traditional modulation format recognition plan, the K-K-coherent-reception-based modulation format recognition methodenables the implementation cost and complexity to be reduced substantially; and on the other hand, the signal amplitude and phase are restored based on the K-K algorithm and the algorithm is implemented simply; and almost all modulation formats can be identified.

A novel polarizing plate is disclosed. The polarizing plate comprises at least a polarizing film, a pressure-sensitive adhesive layer, and an optical compensation sheet, having an absolute value of Y, defined by the following equation, equal to or smaller than 6.0×10⁻⁴:

Y=−7.0×10⁵×Cn+4.3×10⁻¹³×E−1.34×10⁻³

• • where Cn (1/Pa) is photoelastic modulus of said pressure-sensitive adhesive layer and E (Pa) is modulus of elasticity of said optical compensation sheet.

The invention discloses a photoelasticity principle based flexile microprobe and an application method thereof. The photoelasticity principle based flexile microprobe, namely an integral structure made of SU-8 photoresist, comprises a microprobe stress end and a microprobe base body. The microprobe base body comprises a base body end and a base body tail. The base body end and the microprobe stress end are arranged on the same side of the base body tail to form a microprobe structure. The light intensity variation of polarized light transmitting a flexible hinge stress measurement area and a measurement light path is measured, a relationship between the light intensity variation and stress magnitude of the microprobe stress end is established, and accordingly, measurement of micro force can be achieved. The photoelasticity principle based flexile microprobe made of the SU-8 photoresist is low in processing technique cost and high in stability and has the advantages of chemical corrosion resistance, good mechanical property and biocompatibility, high light stress coefficient and the like; moreover, the photoelasticity principle based flexile microprobe of the integral structure is free from assembly, simple to produce and beneficial for functionalization of microoperation techniques in the fields of biomedicine, material chemistry and the like.