摘要:
This invention provides a surface acoustic wave device which comprises a multi-layered substrate. The multi-layered substrate comprises at least a piezoelectric zinc oxide layer, an intermediate silicon oxide layer and an .alpha.-Al.sub.2 O.sub.3 base made of a single crystal havine an (0112) crystallographic plane or an equivalent crystallographic plane. This surface acoustic wave device is operable at ultra-high frequency.
摘要翻译:本发明提供了一种包括多层基板的表面声波装置。 多层基板至少包括压电氧化锌层,中间氧化硅层和由单晶铪(0112)晶面或等效晶面制成的α-Al 2 O 3基底。 该声表面波装置可以超高频工作。
摘要:
A surface acoustic wave device comprising a piezoelectric substrate which comprises an .alpha.-alumina layer as a base region and a zinc oxide layer as a surface region formed on the .alpha.-alumina layer. Preferably the two layers are each made of a single crystal, and the thickness of the zinc oxide layer and an angle between a crystallographic axis of the zinc oxide single crystal and the direction of wave propagation are determined so as to fall within optimum ranges, respectively. This device features an increased phase velocity and an augmented value for the electromechanical coupling coefficient and accordingly is of use at very-high to ultra-high frequencies.
摘要:
A surface acoustic wave transducer has a multilayered substrate which is made of a nonpiezoelectric plate which has a surface which is coated with a piezoelectric film, and has an interdigital electrode which is disposed on or under the surface of the piezoelectric film. The interdigital electrode has a split structure and the phase velocity of the surface acoustic wave of the piezoelectric film is smaller than that of the nonpiezoelectric plate.
摘要:
A surface acoustic wave resonator includes a base plate made of glass and a layer of piezoelectric material which has a plurality of strips extending parallel to each other for forming a reflector. A surface acoustic wave excited from a transducer reflects at each of the strips. The reflectance of such surface acoustic wave is improved by the arrangement of the strips and the thickness of the layer. On the other hand, the temperature coefficient of the resonance frequency is also improved by the arrangement of the strips and the thickness of the layer, and by the amount of the alkali metal oxide contained in the base plate, and further by the thickness of silicon oxide film laminated on the surface of the base plate.
摘要:
This invention provides a multi-layered substrate for a surface-acoustic-wave device which substrate comprises a piezoelectric layer on a base, the temperature coefficient of a phase velocity of the surface-acoustic-wave in the piezoelectric layer being different from that of the base, the piezoelectric layer having a thickness less than a wavelength of the SAW. This multi-layered substrate can have a large electromechanical coupling and controlled temperature coefficient of the phase velocity.
摘要:
Provided from the object side are a first lens group (11) having a positive refracting power and fixed to the image plane, a second lens group (12) having a negative refracting power and a magnification varying action exhibited when moving along the optical axis, a third lens group (13) fixed to the image plane and having a positive refracting power, and a fourth lens group (14) movable along the optical axis so as to maintain the image plane moving with the movements of the second lens group (12) and of the object in a fixed position from a reference plane. Hence the movement of the image due to camera shake is corrected by moving the whole third lens group (13) vertically to the optical axis. The size is reduced and the aberrations are small because the whole groups whose optical performance is united are decentered.
摘要:
A zoom lens is described that includes: a first lens group having positive refracting power and fixed with respect to an image plane; a second lens group having negative refracting power and varying power, wherein the power is varied by moving along an optical axis; a third lens group having positive refracting power and fixed with respect to the image plane; and a fourth lens group having: positive refracting power and moving along an optical axis so as to keep the image plane varied by movement of the second lens group and an object at a predetermined position from a reference surface. The first, second, third, and fourth lens groups are disposed from the object side to the image plane side in this order. The second lens group is composed of two negative lenses and one positive lens. The third lens group is composed of two positive lenses and one negative lens. The fourth lens group is composed of a positive lens. The second to fourth lens groups include at least one aspherical surface, respectively.
摘要:
A device for calculating diffraction efficiencies of a diffraction lens divided into a plurality of regions, each region comprising at least one grating ring, comprises a first memory for storing information about diffraction efficiencies of the regions; a second memory for storing information about weights corresponding to the regions; and a first processor for retrieving information from the first and the second memory, and calculating diffraction efficiencies of the entire diffraction lens using the formula E j = ∑ m = 1 M W m η mj ( 1 ) wherein: j: integer indicating the order of diffraction light Ej: diffraction efficiency for j-th order diffraction light of the diffraction lens M: positive integer (M>1) indicating the number of regions for which the diffraction efficiency is calculated m: index of the region for which the diffraction efficiency is calculated &eegr;mj: diffraction efficiency for the j-th order diffraction light of the m-th region (stored in the first memory) Wm: weight for the m-th region (stored in the second memory means). Thus, the diffraction efficiency of the diffraction lens can be calculated easily.
摘要:
A projection lens for projecting an image appearing on a cathode-ray tube onto a screen, small in residual aberrations, having a high imaging performance, also having a large aperture ratio and a wide field angle, suitable for a video projector having a high definition of, say, 1,125 scanning lines. The projection lens has, successively from the screen side, a Gauss type lens system, a positive lens mainly for enlarging the aperture ratio, and a negative lens mainly for widening the field angle, which negative lens has a strongly concave surface at the screen end.
摘要:
Provided from the object side are a first lens group (11) having a positive refracting power and fixed to the image plane, a second lens group (12) having a negative refracting power and a magnification varying action exhibited when moving along the optical axis, a third lens group (13) fixed to the image plane and having a positive refracting power, and a fourth lens group (14) movable along the optical axis so as to maintain the image plane moving with the movements of the second lens group (12) and of the object in a fixed position from a reference plane. Hence the movement of the image due to camera shake is corrected by moving the whole third lens group (13) vertically to the optical axis. The size is reduced and the aberrations are small because the whole groups whose optical performance is united are decentered.