Abstract: On a waveguide 34 formed on a substrate 33, a plurality of comblike shaped electrodes 37, 38 that generate surface acoustic waves 37a, 38a from different directions are provided. And a periodic refractive indices portion 40 is formed, where the refractive indices are periodically distributed in accordance with the wavelengths of the surface acoustic waves 37a, 38a generated by applying a voltage to the comblike shaped electrodes 37, 38. And by changing a frequency of the applying voltage for sequentially changing the wavelengths of the surface acoustic waves 37a, 38a, the exiting direction of the light exiting from the periodic refractive indices portion 40 is scanned. This makes it possible to provide an optical functional device and an optical scanning apparatus that perform light scanning less costly but at a high speed, and that can secure a wide scanning angle.

Abstract: An acousto-optic deflector which has a thin film waveguide layer on a buffer layer formed on a substrate and an IDT and light incidence/emergence means on the thin film waveguide layer. As the thin film waveguide layer, a piezoelectric material such as a ZnO film is used. As the substrate, a material with a resistivity of not more than 20 &OHgr;cm is used. Sezawa waves are excited on the thin film waveguide layer by the IDT, and a laser beam traveling in the thin film waveguide layer is deflected by the Sezawa waves. If the ZnO thin film waveguide layer has a thickness of h and if the excited Sezawa waves have a wavelength of &lgr;, 0.2<h/&lgr;<0.5 is fulfilled.

Abstract: A thin film waveguide and an optical deflecting device which have a substrate and a waveguide layer. An optical buffer layer which has a refractive index smaller than that of the waveguide layer is provided between the substrate and the waveguide layer, and the optical buffer layer has such a thickness as to make a zero mode guided light beam progressing in the waveguide layer have a propagation loss not more than 2 dB/cm and as to make a first mode guided light beam progressing in the waveguide layer have a propagation loss not less than 4 dB/cm. For example, the waveguide layer is a ZnO thin film, the substrate is a silicon substrate, and the optical buffer layer is a SiO.sub.2 thin film. Further, an interdigital transducer is provided on the waveguide layer to excite Sezawa waves as surface acoustic waves. For example, the waveguide layer is designed to have a thickness which meets the following condition: 1.0<hK<5.0 (K=2 .pi./.LAMBDA.), wherein, h is the thickness of the waveguide layer, and .

Abstract: An optical deflector which has a waveguide, an interdigital transducer which is provided on the waveguide to convert a high-frequency signal to excite surface acoustic waves, a light incidence section for making a light beam incident to the waveguide and a light emergence section for making a light beam progressing in the waveguide emergent therefrom, and a scanning optical system provided with the optical deflector. The interdigital transducer is a chirp type and has finger electrodes which are so designed that an emergent light beam from the optical deflector will have a substantially fixed intensity in a deflection range. More specifically, the finger electrodes of the interdigital transducer are overlap-weighted so that an emergent light beam from the optical deflector will have a substantially fixed intensity in a deflection range.

Abstract: The disclosed acousto-optic scanning device includes a thin film waveguide of piezoelectric material (2), a transducer (3) for generating surface elastic waves, and a high frequency signal generator (4) for generating high frequency signals to be applied to the transducer. Additionally, the device includes a light source (10), light source driver (11) for driving the light source, a prism or grating input and output light couplers (7, 8 or 27, 28) for introducing light emitted from the light source into the thin film waveguide and for outputting light transmitted through the thin film waveguide therefrom. Further, the device includes non-coupled light photodiode detector array (14) for detecting the position and intensity of light which is not coupled by the output light coupling means, and a signal processor for processing information detected by the non-coupled light detector array and generating control signals to correct the position and intensity of coupled light.

Abstract: A solid-state image sensing apparatus comprises a charge coupled device, a plurality of photosensors, and a voltage generator. Each of the photosensors receives incident light, generates a voltage logarithmically proportional to an intensity of the incident light, and is connected to a first electrode of the charge coupled device. The voltage generator generates a reference voltage logarithmically proportional to an average intensity of the incident light on the photosensors and is connected to a second electrode of the charge coupled device. Signal charges are injected into the charge coupled device, depending on the voltage impressed on the first and second electrodes, so that a direct current component of an output of the charge coupled device is controlled.