Provided is an evaluation method capable of evaluating stress on a bond which is difficult to detect by Raman spectroscopy. The present disclosure relates to an evaluation method including using infrared absorption spectra measured on a rubber specimen under application of no tensile force and under application of a tensile force to calculate an amount of peak shift caused by application of the tensile force, and evaluating stress in the rubber specimen from the amount of peak shift.

An apparatus includes a light source configured to emit light to a translucent material and an embedded feature disposed in the translucent material, a first linear polarizer configured to linearly polarize the emitted light, based on a first orientation of an optical axis of the first linear polarizer, and a second linear polarizer configured to filter the light that is reflected from the translucent material, from the light that is reflected from the embedded feature and the translucent material, based on a second orientation of an optical axis of the second linear polarizer. The apparatus further includes a sensor configured to receive the light reflected from the embedded feature, from which the light reflected from the translucent material is filtered, and capture an image of the embedded feature and the translucent material, based on the received light.

To provide an internal stress confirming method of a resin which is capable of measuring an internal stress of a translucent resin such as a fluororesin and a fluororubber and dynamically confirming stress propagation, and an apparatus measuring for the same. The internal stress confirming method for confirming an internal stress of a measurement target containing a translucent resin includes irradiating the measurement target with near-infrared light having a peak wavelength in a near-infrared band of 800 nm to 2500 nm through frosted glass, a polarizer, and a wavelength plate; acquiring a near-infrared image by imaging the measurement target through a wavelength plate and an analyzer; and confirming the internal stress of the measurement target based on the near-infrared image.

A testing apparatus may include a stand having an aperture and a platform adjacent to the aperture, a clamp adjacent to the platform and configured to hold a coupon, and an actuator within the aperture. The actuator is configured to impart a first force on the platform and the coupon at a specified frequency. The testing apparatus may also include a displacement sensor adjacent to the stand and configured to measure a displacement of the coupon and circuitry connected to the actuator and the displacement sensor with the circuitry configured to collect data from the actuator and the displacement sensor.

A light emitting apparatus has a visible light emitter, an invisible light emitter, invisible light receiver for receiving invisible light emitted from the invisible light emitter, cover member covering these components, and controller for controlling operation of the visible light emitter. The cover member has flexibility so as to deform when receiving external force, and at least partially reflects invisible light and passes and diffuses visible light. The invisible light emitter emits invisible light toward an inside surface of the cover member, and the invisible light receiver receives invisible light and reflected by the cover member. The controller controls an emission mode of visible light emitted from the visible light emitter in accordance with a reception state of invisible light at the invisible light receiver, which changes in accordance with deformation of the cover member.

Prism-coupling systems and methods for characterizing large depth-of-layer waveguides formed in glass substrates are disclosed. One method includes making a first measurement after a first ion-exchange process that forms a deep region and then performing a second measurement after a second ion-exchange process that forms a shallow region. Light-blocking features are arranged relative to the prism to produce a mode spectrum where the contrast of the mode lines for the strongly coupled low-order modes is improved at the expense of loss of resolution for measuring characteristics of the shallow region. Standard techniques for determining the compressive stress, the depth of layer or the tensile strength of the shallow region are then employed. A second measurement can be made using a near-IR wavelength to measure characteristics of the deeper, first ion-exchange process. Systems and methods of measuring ion-exchanged samples using shape control are also disclosed.

A stretchable strain sensor includes a light-emitting element, an optical structure, and a photo-detective element. The stretchable strain sensor is located in a path of light emitted from the light-emitting element. The optical structure is configured to have optical properties that change in response to stretching of at least a portion of the stretchable strain sensor. The photo-detective element is configured to detect light transmitted through the optical structure or reflected through the optical structure.

Exemplary systems, methods, and devices are provided for measuring a force. Thus, the exemplary systems, methods, and devices can provide a remote optical sensor configured to measure force within the nanonewton range. The remote optical sensor can use avalanching nanoparticles to measure the force in that nanonewton range, where the brightness of the avalanching nanoparticles can be correlated to the applied force.

According to an aspect, a detection device includes: a sensor comprising a plurality of optical sensor elements arranged two-dimensionally; and an acquirer configured to acquire a pattern of a blood vessel of a human finger that is included in a light intensity pattern of light detected by the sensor. The acquirer is configured to acquire information on force from the finger toward the sensor based on the light intensity pattern.