Abstract: A multilayered optical security device has a resonant waveguide grating (RWG) layer on an under layer having a hologram. The RWG layer has plural RWGs for generating one or more patterns. Each RWG has first and second RWG portions, with diffraction gratings of different grating periods, for light coupling-in and coupling-out, respectively. Using the RWGs minimizes interference to a holographic image generated by the under layer. This advantage is especially useful when the holographic image carries digital data such as in digital holographic encryption where an encrypted hologram is used in the under layer. The digital data may contain biometric information such as a fingerprint. In each RWG portion of an individual RWG, scattering elements in a grating are curved to thereby enhance an angular tolerance in azimuthal angle during observing the patterns by an observer while the individual RWG is still selective in elevation angle.

Abstract: A multi-functional precious stone testing apparatus includes a portable housing and a testing unit. The portable housing includes a portable housing having a hand-held casing and a probe casing extended from a front end of the hand-held casing. The testing unit housed in the hand-held casing includes a UV light emission unit, a UV light reflecting and guiding unit, and a UV light receiving unit. The UV light emission unit produces and emits both a long-wave UV light and a short-wave light, so as to allow the UV receiving unit to sense the UV lights reflected and refracted by a testing object for determining various qualities and distinguishing types of diamond of the testing object.

Abstract: Polarization-independent focusing is advantageously achieved by a multifocal system having a polarization beam splitter (PBS) to split an unpolarized light beam into two orthogonally linearly-polarized (LP) light beams. The two LP light beams are reflected by mirrors to travel in opposite directions and enter into a variable-focusing module at two ends thereof, respectively. The module includes waveplates to convert the LP light beams into two circularly-polarized (CP) light beams at both ends of an optical assembly. The optical assembly is formed with a stack of birefringent optical elements including at least one geometric phase lens and one polarization selector that may be electrically modulated to select the optical power in focusing the two CP light beams. Followed by the waveplates converting two focused CP light beams to two focused LP light beams and upon mirror reflection, the beams are finally recombined by the PBS to form one focused light beam.

Abstract: A multi-functional precious stone testing apparatus includes a portable housing, a testing unit, and an indication unit. The portable housing includes a hand-held casing and a probe casing extended from a front end of the hand-held casing. The testing unit includes a conductive probe, a sensor, and a UV light source for emitting UV light beam, so as to allow the sensor to sense the UV reflected and refracted by a testing object for determining various qualities of the testing object.

Abstract: A multilayered optical security device has a resonant waveguide grating (RWG) layer on an under layer having a hologram. The RWG layer has plural RWGs for generating one or more patterns. Each RWG has first and second RWG portions, with diffraction gratings of different grating periods, for light coupling-in and coupling-out, respectively. Using the RWGs minimizes interference to a holographic image generated by the under layer. This advantage is especially useful when the holographic image carries digital data such as in digital holographic encryption where an encrypted hologram is used in the under layer. The digital data may contain biometric information such as a fingerprint. In each RWG portion of an individual RWG, scattering elements in a grating are curved to thereby enhance an angular tolerance in azimuthal angle during observing the patterns by an observer while the individual RWG is still selective in elevation angle.

Abstract: Polarization-independent focusing is advantageously achieved by a multifocal system having a polarization beam splitter (PBS) to split an unpolarized light beam into two orthogonally linearly-polarized (LP) light beams. The two LP light beams are reflected by mirrors to travel in opposite directions and enter into a variable-focusing module at two ends thereof, respectively. The module includes waveplates to convert the LP light beams into two circularly-polarized (CP) light beams at both ends of an optical assembly. The optical assembly is formed with a stack of birefringent optical elements including at least one geometric phase lens and one polarization selector that may be electrically modulated to select the optical power in focusing the two CP light beams. Followed by the waveplates converting two focused CP light beams to two focused LP light beams and upon mirror reflection, the beams are finally recombined by the PBS to form one focused light beam.

Abstract: A multi-functional precious stone testing apparatus includes a microcontroller, a measuring unit for measuring properties of the testing object, and a functional unit. The measuring unit is arranged to measure one of a combination of ultraviolet and infrared distributions of the testing object and a combination of thermal and electrical conductivities of the testing object. The microcontroller analyzes a result from the measuring unit to generate a test result of the testing object, wherein the microcontroller includes a communication unit for connecting with an electronic device to transmit the test result thereto. The functional unit includes a voice indicator that generates a voice indication signal of the test result.

Abstract: A rotational geometric phase hologram has geometric phase optical elements (GPOEs) serially cascaded along a common optical axis to form a GPOE cascade used for receiving a linearly-polarized light beam and generating output light beams at an exit surface of the last GPOE. Interference occurred in the output light beams creates a polarization interference pattern on the exit surface. A photoalignment substrate, when positioned in close proximity to the exit surface, records the pattern. Advantageously, each GPOE is rotatable about the common optical axis. Respective rotation angles of the GPOEs are determined according to a spatially-varying linear polarization orientation distribution selected to be generated for the polarization interference pattern.

Abstract: A multi-functional precious stone testing apparatus includes a portable housing, a testing unit, and an indication unit. The portable housing includes a hand-held casing and a probe casing extended from a front end of the hand-held casing. The testing unit includes a conductive probe, a sensor, and a UV light source for emitting UV light beam, so as to allow the sensor to sense the UV reflected and refracted by a testing object for determining various qualities of the testing object.

Abstract: A rotational geometric phase hologram has geometric phase optical elements (GPOEs) serially cascaded along a common optical axis to form a GPOE cascade used for receiving a linearly-polarized light beam and generating output light beams at an exit surface of the last GPOE. Interference occurred in the output light beams creates a polarization interference pattern on the exit surface. A photoalignment substrate, when positioned in close proximity to the exit surface, records the pattern. Advantageously, each GPOE is rotatable about the common optical axis. Respective rotation angles of the GPOEs are determined according to a spatially-varying linear polarization orientation distribution selected to be generated for the polarization interference pattern.

Abstract: A multi-functional precious stone testing apparatus includes a portable housing, a testing unit, and an indication unit. The portable housing includes a hand-held casing and a probe casing extended from a front end of the hand-held casing. The testing unit includes a conductive probe having a testing end portion extended out of a tip end of the probe casing for contacting a testing object to determine a conductivity of the testing object. The indication unit includes a LED light unit received in the hand-held casing for illuminating the testing end portion of the conductive probe during testing, wherein the LED light unit is positioned away from the tip end of the probe casing for preventing heat generated from the LED light unit being transmitted toward the conductive probe to affect an accurate measurement for the conductivity of the testing object.

Abstract: A jewelry storage device includes a box body unit and a locking unit. The box body unit includes a first body, and a second body, wherein a plurality of first and second connecting members are formed at rear sides of the first and second bodies respectively and are coupled with each other to pivotally connect the first body with the second body. The locking unit includes a mortice lock member and a locking member provided at front sides of the first and second bodies respectively in a hidden manner. The first and second connecting members are not protruded from the rear sides of the first and second bodies respectively. The mortice lock member and the locking member are not protruded from the front sides of said first and second bodies respectively. Therefore, the box body unit has no protruded portion formed at the first and second bodies.

Abstract: A device for controllably deflecting a first circularly-polarized (CP) light beam from an incident direction with fast response comprises a polarization selector (PS) to adjust the incident light beam's sense of rotation to a desired one to form a second CP light beam, and a polarization grating (PG) to deflect the second CP light beam according to the desired sense of rotation. The PS comprises an optical modulator sandwiched between two quarter-wave plates. The optical modulator has at least one ferroelectric liquid crystal (FLC) half-wave plate (HWP) being reconfigurable in fast axis orientation. The device has a fast response in beam steering due to a short time of reconfiguring the FLC HWP. Based on serially cascading multiple units each being this device, a beam-steering apparatus having fast response and enhanced steering resolution is obtained. The apparatus is usable for enhancing a field of view in projecting an image.

Abstract: A multi-functional precious stone testing apparatus includes a microcontroller, a measuring unit for measuring properties of the testing object, and a functional unit. The measuring unit is arranged to measure one of a combination of ultraviolet and infrared distributions of the testing object and a combination of thermal and electrical conductivities of the testing object. The microcontroller analyzes a result from the measuring unit to generate a test result of the testing object, wherein the microcontroller includes a communication unit for connecting with an electronic device to transmit the test result thereto. The functional unit includes a voice indicator that generates a voice indication signal of the test result.

Abstract: A multi-functional precious stone testing apparatus includes a portable housing, a testing unit, and an indication unit. The portable housing includes a hand-held casing and a probe casing extended from a front end of the hand-held casing. The testing unit includes a conductive probe having a testing end portion extended out of a tip end of the probe casing for contacting a testing object to determine a conductivity of the testing object. The indication unit includes a LED light unit received in the hand-held casing for illuminating the testing end portion of the conductive probe during testing, wherein the LED light unit is positioned away from the tip end of the probe casing for preventing heat generated from the LED light unit being transmitted toward the conductive probe to affect an accurate measurement for the conductivity of the testing object.

Abstract: A multi-functional precious stone testing apparatus includes a microcontroller, a measuring unit for measuring properties of the testing object, and a functional unit. The measuring unit is arranged to measure one of a combination of ultraviolet and infrared distributions of the testing object and a combination of thermal and electrical conductivities of the testing object. The microcontroller analyzes a result from the measuring unit to generate a test result of the testing object, wherein the microcontroller includes a communication unit for connecting with an electronic device to transmit the test result thereto. The functional unit includes a voice indicator that generates a voice indication signal of the test result.

Abstract: A multi-functional precious stone testing apparatus includes a portable housing, a testing unit, and an indication unit. The portable housing includes a hand-held casing and a probe casing extended from a front end of the hand-held casing. The testing unit includes a conductive probe having a testing end portion extended out of a tip end of the probe casing for contacting a testing object to determine a conductivity of the testing object. The indication unit includes a LED light unit received in the hand-held casing for illuminating the testing end portion of the conductive probe during testing, wherein the LED light unit is positioned away from the tip end of the probe casing for preventing heat generated from the LED light unit being transmitted toward the conductive probe to affect an accurate measurement for the conductivity of the testing object.

Abstract: The presently claimed invention provides a phase modulator for a see-through display, and the corresponding fabrication methods. The phase modulator comprises a liquid crystal layer having at least two types of domains including a first domain having a first refractive index and a second domain having a second refractive index. The phase modulator is able to increase field of view without inducing the problem of the fringe field effect between two adjacent pixels.