Abstract: An optical member manufacturing method of the present invention has a growth step of growing an ingot of a fluoride crystal, a plane orientation measurement step of measuring two or more crystal plane orientations of the ingot, a cutout step of cutting out an optical material from the ingot along any one of the crystal plane orientations obtained in the plane orientation measurement step, and a machining step of performing predetermined machining processing on the optical material to obtain an optical member.

Abstract: In a TDMA/TDD communication system, uplink RF bursts are received by a number of antennas. Each RF burst contains TDMA signals identified by mobile-terminal identifiers. From each RF burst, the strength of the TDMA signals are detected and compared with the strengths of other RF bursts. For each mobile-terminal identifier, one antenna is selected as a best antenna with the highest strength, and a unique relationship is established in a memory between the selected antenna and the mobile-terminal identifier. A downlink TDM signal is disassembled into time slot signals, which are assembled, according to the relationships established in the memory, into N multicast burst groups. N is equal to the number of antennas selected during the uplink interval. An overhead is inserted to a header portion of each burst group. Overhead-inserted burst groups are converted into RF bursts during a downlink interval of the frame and are transmitted.

Abstract: A method for manufacturing an optical member of a fluoride crystal includes: a growing step of growing an ingot of a fluoride crystal; a cutting-out step of cutting out from the ingot a cylindrical basic material with two parallel planes which have a certain crystal plane orientation; an orientation-determining step of determining a crystal orientation of a side surface of the cylindrical basic material; a birefringence-measuring step of measuring birefringence in a specific crystal axis direction at the side surface determined based on the crystal orientation determined in the orientation-determining step; and an evaluating step of evaluating the fluoride crystal on the basis of a result of measurement of the birefringence. A fluoride crystal is obtained in which a maximum value of birefringence in a specific crystal axis direction at a side surface is not more than 10 nm/cm at a measurement wavelength of 633 nm.

Abstract: An optical device for a photolithography apparatus comprises a lens formed of a fluoride crystal material, a holder holding the lens, and a pressing member attached to the holder and pressing the lens to generate a stress in the lens. The stress can be generated in the lens by pressing the lens in a specified orientation with the pressing member to reduce the birefringence of the lens. When the lens is composed of a calcium fluoride crystal, the maximum value of the birefringence amount with respect to a light beam having a wavelength of about 157 nm can be made not more than 2.0 nm/cm within an effective aperture (light-transmitting area) of the lens, or the maximum value of the birefringence amount with respect to a light beam having a wavelength of about 193 nm can be made not more than 1.0 nm/cm within the effective aperture of the lens.

Abstract: A manufacturing method for a single crystal of calcium fluoride by which it is possible to obtain a single crystal of calcium fluoride with adequately small double refraction, which can be used in optical systems for photolithography, and in particular, a single crystal of calcium fluoride with a large diameter (ø200 mm or larger) having superior optical properties, which can be used for photolithography with a wavelength of 250 nm or less.

Abstract: A method for evaluating an optical member for photolithography composed of a fluoride crystal comprises a step of measuring a crystal plane orientation of the optical member, and a step of specifying a twin region on the basis of a result of the measurement. The twin region in an effective region of an optical element is specified as a total area of a region obtained by projection onto a plane perpendicular to an optical axis of the optical element. It is judged that the optical member is usable when the total area is not more than 10% of an effective diametric area or a partial diametric area of the optical element. The obtained optical element has satisfactory image formation characteristics because of less birefringence.

Abstract: An optical member manufacturing method of the present invention has a growth step of growing an ingot of a fluoride crystal, a plane orientation measurement step of measuring two ormore crystal plane orientations of the ingot, a cutout step of cutting out an optical material from the ingot along any one of the crystal plane orientations obtained in the plane orientation measurement step, and a machining step of performing predetermined machining processing on the optical material to obtain an optical member.

Abstract: The optical member of the present invention is an optical member comprising a fluoride crystal; and having an optical axis forming an angle of 10° to 36° with a <111> axis of the fluoride crystal, and a birefringence of 2.0 nm/cm or less in the optical axis direction. The optical member of the present invention can improve the yield and processing accuracy in the process of making the optical member, and can achieve sufficiently high optical characteristics.

Abstract: An RSSI block cumulating circuit block-cumulates an RSSI signal that has been A/D converted and calculates an RSSI signal in a low level. An RSSI level raising circuit raises the level of the RSSI signal and outputs the resultant signal as a threshold value. An RSSI continuous cumulating circuit always cumulates the RSSI signal. A comparing circuit compares the threshold value with the output signal of the RSSI continuous cumulating circuit and determines whether or not a carrier is present.

Abstract: An improved system and method for canceling a DC offset and measuring a carrier detection threshold value. A control circuit provides a signal based upon a frame synchronizing signal for shutting down the power to a mixer. Thereafter, at a predetermined time, the control circuit provides a signal to a DC offset cancel circuit to cancel the DC offset. Then, the control circuit provides a RSSI gate signal to a carrier detection circuit based upon the next frame synchronizing signal, for determining whether a carrier exists.

Abstract: A method for evaluating an optical member for photolithography composed of a fluoride crystal comprises a step of measuring a crystal plane orientation of the optical member, and a step of specifying a twin region on the basis of a result of the measurement. The twin region in an effective region of an optical element is specified as a total area of a region obtained by projection onto a plane perpendicular to an optical axis of the optical element. It is judged that the optical member is usable when the total area is not more than 10% of an effective diametric area or a partial diametric area of the optical element. The obtained optical element has satisfactory image formation characteristics because of less birefringence.

Abstract: The present invention provides a method for calculating the birefringence of an optical element and selecting the direction of minimum birefringence in the optical element. The birefringence of the optical element is calculated by converting known piezo-optical constants in a specified three-dimensional orthogonal coordinate system for the optical material into piezo-optical constants in an arbitrary three-dimensional orthogonal coordinate system. The amount of change in the refractive index &Dgr;n1 of the optical material in a first direction and the amount of change in the refractive index &Dgr;n2 of the optical material in a second direction which is perpendicular to the first direction are calculated using a uniaxial stress that is applied to the optical material along the first direction.

Abstract: An optical member for photolithography made of a calcium fluoride crystal exhibits an internal transmittance of 99.5%/cm or greater with respect to light having a specific wavelength of 185 nm or shorter.

Abstract: A manufacturing method for a single crystal of calcium fluoride by which it is possible to obtain a single crystal of calcium fluoride with adequately small double refraction, which can be used in optical systems for photolithography, and in particular, a single crystal of calcium fluoride with a large diameter (ø200 mm or larger) having superior optical properties, which can be used for photolithography with a wavelength of 250 nm or less.

Abstract: A manufacturing method for a single crystal of calcium fluoride by which it is possible to obtain a single crystal of calcium fluoride with adequately small double refraction, which can be used in optical systems for photolithography, and in particular, a single crystal of calcium fluoride with a large diameter (ø 200 mm or larger) having superior optical properties, which can be used for photolithography with a wavelength of 250 nm or less.

Abstract: A mobile communication terminal includes a location information database storing location data and map data for each of the radio cell stations. When receiving a data request including an identification of a second mobile terminal from a first mobile terminal through a first radio cell station, the database is searched for first location data of the first radio cell station, second location data of a second radio cell station forming a micro cell in which the second mobile terminal is located, and map data for at least one of the first and second radio cell stations. Then the first and second location data and retrieved map data are transferred to the first mobile terminal through the first radio cell station and thereby a map and two locations corresponding to the first and second mobile terminals are displayed on screen based on the retrieved map data and the first and second location data.

Abstract: The present invention provides a method for calculating the birefringence of an optical element and selecting the direction of minimum birefringence in the optical element. A material for manufacturing the optical element is a fluoride single crystal with a birefringence value that is reduced compared to conventional materials. The fluoride single crystal is cut from a fluoride single crystal ingot obtained by crystal growth so that the {111} crystal planes are two parallel planes, after which the optical performance is improved by subjecting this material to a heat treatment. The birefringence of the optical element is calculated by converting known piezo-optical constants in a specified three-dimensional orthogonal coordinate system for the optical material into piezo-optical constants in an arbitrary three-dimensional orthogonal coordinate system.

Abstract: A mobile wireless terminal comprises an RF receiving means for receiving a transmission radio wave received from a base station on a designated channel, a waveform equalizer for equalizing waveform distortion of a signal received by said RF receiving means, a unique word detector for detecting a unique word from a reception signal sequence whose waveform distortion has been equalized by said waveform equalizer, a channel switching controlling means for switching the current reception channel of said RF receiving means to another reception channel corresponding to a channel switch request, a carrier detector for detecting whether or not a transmission radio wave has been received by said RF receiving means and supplying a channel switch request to said channel switching controlling means when the transmission radio wave has not been received for a predetermined time period, and a sliding controlling means for performing an on/off control for the power of said waveform equalizer at predetermined intervals for a

Abstract: The present invention provides a method for calculating the birefringence of an optical element and selecting the direction of minimum birefringence in the optical element. A material for manufacturing the optical element is a fluoride single crystal with a birefringence value that is reduced compared to conventional materials. The fluoride single crystal is cut from a fluoride single crystal ingot obtained by crystal growth so that the {111} crystal planes are two parallel planes, after which the optical performance is improved by subjecting this material to a heat treatment. The birefringence of the optical element is calculated by converting known piezo-optical constants in a specified three-dimensional orthogonal coordinate system for the optical material into piezo-optical constants in an arbitrary three-dimensional orthogonal coordinate system.

Abstract: An optical member is provided for use in an image-focusing optical system for guiding light having a wavelength shorter than about 300 nm. The optical member includes a calcium fluoride crystal having a sodium concentration of less than about 0.2 ppm.