Abstract: A digital imaging device includes an image sensor for sensing an image of an object; an image data processor for encoding image data contained in a digital signal of the object sensed by the image sensor, into a digital image of the object; and a watermark generating unit for generating a digital watermark which is embedded in the digital image of the object. Further, a method of identifying a digital imaging device from a digital image of an object produced by the imaging device includes providing the digital imaging device with a watermark generating unit; and embedding a digital watermark generated by the watermark generating unit in the digital image of the object.

Abstract: A cladding layer structure of a LED (light emitting diode) package structure comprises a printed circuit layer arranged on a substrate, a cladding layer having a through hole is located on the printed circuit layer, a chip is received in the through hole and is in electrical contact with the printed circuit layer via a welding wire. Resin is located on the printed circuit layer and filled in the through hole of the cladding layer for sealing the chip. And an optical lens is placed on the cladding layer.

Abstract: A sealing structure for a white light LED comprises a printed circuit layer located on a base, a cladding layer having a through hole is arranged on the printed circuit layer. A chip is received in the through hole and is electrically connected to the printed circuit layer by a welding wire. The through hole is filled with resin for sealing the chip and the welding wire and the surface of the printed circuit layer. A fluorescent film having well-distributed fluorescent substances is received in the through hole for covering the resin, and then an optical lens is laid over the fluorescent film and the cladding layer. Such structure can provide a white light LED light source with even brightness and luminance.

Abstract: A semiconductor package includes a substrate, a first chip, a nonconductive adhesive, a second chip and a plurality of supporting balls. The first chip has an upper surface and a lower surface opposite to the upper surface, and the lower surface is mounted on the substrate. The nonconductive adhesive is disposed on the upper surface of the first chip. The second chip has an upper surface and a lower surface opposite to the upper surface, wherein the lower surface is mounted on the upper surface of the first chip by means of the nonconductive adhesive, and the adherent area between the nonconductive adhesive and the second chip is larger than 90% of the area of the lower surface of the second chip. The supporting balls are disposed in the nonconductive adhesive for supporting the second chip.

Abstract: A dynamic range extender for optical transmitters comprises a bipolar distortion compensator for increasing drive signal gain as the absolute level of an input signal increases beyond a selected input voltage threshold, a signal coupler for dividing the input signal into complementary signals, a unipolar distortion compensator for increasing drive signal gain of each complementary signal beyond a selected forward current threshold, a signal clipper for pre-clipping each complementary signal below a selected clipping threshold, and complementary driver outputs to drive each of a pair of laser diodes in a complementary push-pull arrangement. The pre-clipping prevents the laser diodes from being driven below their threshold current level, and the distortion compensation suppresses second and third order harmonic distortion when the complementary signals generated by the laser diodes are combined by differential photodiodes.

Abstract: A method for linearizing optical transmission systems that includes an optical linearizer connected to the output of the optical transmitter. From the output, which includes a modulated signal and a transmitter distortion, the linearizer interacts with the wavelength chirping (d&lgr;c) of the transmitter output. More specifically, the linearizer is characterized by a wavelength dependent optical transfer curve F(&lgr;) that utilizes d&lgr;c to induce a compensation distortion. Further, the optical transfer curve F(&lgr;) has a reference wavelength (&lgr;p) and an operating point wavelength offset (&Dgr;&lgr;b). In operation, (&lgr;p+&Dgr;&lgr;b) of the optical transfer curve F(&lgr;) is aligned with (&lgr;c) of the output to establish an effective value for the compensation distortion. This compensation distortion is then added with the transmitter distortion to cancel the transmitter distortion from the modulated signal; to thereby linearize the output.

Abstract: A method for linearizing optical transmission systems that includes an optical linearizer connected to the output of the optical transmitter. From the output, which includes a modulated signal and a transmitter distortion, the linearizer interacts with the wavelength chirping (d&lgr;c) of the transmitter output. More specifically, the linearizer is characterized by a wavelength dependent optical transfer curve F(&lgr;) that utilizes d&lgr;c to induce a compensation distortion. Further, the optical transfer curve F(&lgr;) has a reference wavelength (&lgr;p) and an operating point wavelength offset &Dgr;&lgr;b. In operation, (&lgr;p+&Dgr;&lgr;b) of the optical transfer curve F(&lgr;) is aligned with (&lgr;c) of the output to establish an effective value for the compensation distortion. This compensation distortion is then added with the transmitter distortion to cancel the transmitter distortion from the modulated signal; to thereby linearize the output.

Abstract: An optoelectronic switch for switching an input signal comprises two PIN des connected in series with opposed polarity, an input signal choke connected to the PIN diodes for presenting a high impedance to the input signal and a low impedance to a PIN diode bias, and a photovoltaic cell connected to the PIN diodes and the input signal choke for generating the PIN diode bias to switch the PIN diodes between a substantially conductive state while the photovoltaic cell receives optical energy from a light source and a substantially non-conductive state while the photovoltaic cell does not receive optical energy from the light source.

Abstract: A retroreflective button includes: a front mirror surface formed on a front surface of the button, a plurality of micro prisms each being polygonal shape and capable of transmitting and reflecting light from the polyhedral facets of each micro prism for retroreflecting an incoming light as emitted from a light or illuminating source for warning and optical decorative purposes, and a fastening device formed on a rear portion of each button to be secured on a wearer's garment or the like.

Abstract: A resonant driving circuit for a laser diode comprises an impulse generator for generating narrow output pulses, a delay line for generating a composite output of reflections of the output pulses from terminations of the transmission line, a laser diode for generating an optical output from the composite output, and a forward bias network to bias the laser diode.

Abstract: The optoelectronic switch of the present invention comprises two PIN diodes onnected in series with opposed polarity having their intrinsic regions coupled to a light source for maintaining both diodes in the conductive state while the light source is on and in the non-conductive state while the light source is off.

Abstract: A reflector includes a rotor disk rotatably mounted on a bike spoke having two semi-circular blades respectively formed on two surfaces of the rotor disk for driving a rotation of the rotor disk when subjected to a wind force when driving a bike, and having a retroreflective surface and a light-absorptive surface respectively formed on two opposite surfaces of the rotor disk for producing a flashing operation when rotating the disk, thereby providing a dynamic flashing reflector on a bike or the like for traffic warning or interesting purpose.

Abstract: A novel bridge type optoelectronic (OE) sample and hold circuit based upon current steering demonstrates a clear superiority in performance with respect to a direct OE sample and hold circuit. The bridge type OE sample and hold circuit permits a high-speed signal to be sampled with high accuracy to offer high charging capability, commanding signal isolation, reduced time jitter and reduced holding charge leakage which are distinct advantages over conventional electronic sample and hold circuits.

Abstract: A road sign includes: a rotor disk rotatably mounted on a frame having a retroreflective sheet formed on a first surface of the rotor disk capable of reflecting any incident light projecting onto the retroreflective sheet for forming a bright surface of said disk, and a light-absorptive surface formed on a second surface of the rotor disk opposite to the first surface capable of absorbing incoming lights projecting onto the light-absorptive surface for forming a dark surface of the disk, whereby upon a blowing of wind on the rotor disk, the disk will be rotated to subsequently orient the first bright surface frontwardly and then orient the second dark surface frontwardly, thereby causing a flashing operation for serving as an effective road sign.