Eiichi Seya

Operation of a separated-type x-ray interferometer for phase-contrast x-ray imaging

Aiming at large-area phase-contrast x-ray imaging, a separated-type x-ray interferometer system was designed and developed to produce 25×20 mm interference patterns. The skew-symmetric optical system was adopted because of the feasibility of alignment. The rotation between the separated crystal blocks was controlled within a drift of 0.06 nrad using a feedback positioning system. This interferometer generated a 25×15 mm interference pattern with 0.07 nm synchrotron x-rays. A slice of a rabbit’s kidney was observed, and its tubular structure could be revealed in a measured phase map.

Large-area phase-contrast X-ray imaging using a two-crystal X-ray interfero­meter

Large-area (25 x 20 mm) phase-contrast X-ray imaging was attained by using a skew-symmetric two-crystal X-ray interferometer. The sub-nrad angular control required to operate the X-ray interferometer was achieved with a sleeve bearing and a feedback-positioning system. As a demonstration, measurements of a phase map of a rats liver and a phase-contrast tomographic three-dimensional image of a piece of a rabbits liver were performed at the Photon Factory using 0.07 nm synchrotron radiation X-rays.

Development Of A Precision Diamond Cutting Machine For Fabrication Of Asymmetrical Aspheric Mirrors

A high-precision, numerically controlled, diamond cutting machine has been developed for fabrication of asymmetrical aspheric mirrors, such as toroidal mirrors used in SOR optics. In this machine, a work-piece is securely fixed to a machine base, and its side face is cut by a flying single-point diamond tool. A tool spindle is laid on an X-Y slide, and its position is numerically controlled by using a laser interferometer. It is possible to fabricate a cylindrical surface by having the spindle-axis rotate slightly about an axis perpendicular to the X-Y slide. Furthermore, while the spindle is rotating, cutting-depth can be dynamically controlled by utilizing a piezo-actuator fixed to the diamond tool. The cutting-depth control is synchronized to the current rotation angle of the spindle, and cutting-depth data are numerically programmed as function of X-Y slide position. A suitable combination of these programmable figure parameters allows fabrication of asymmetrical aspheric mirrors. In order to achieve high figure accuracy, accurate straight motion is required with the X-Y slide. Therefore, straightness error compensation control is adopted, which incorporates a ZERODURE straightedge of 1m length and three optical-fiber gap sensors. The machine accepts a work-piece with maximum dimensions of 600mm length and 100mm width. A figure accuracy of 0.1 μm and surface roughness of 0.03μmRmax have been achieved.

Stacked Optical Disk Drive for Multimedia Files

A stacked optical disk drive with multiple optical heads has been developed for large-capacity multimedia files. This drive will be suitable for such applications as a network database through LAN, a picture library Including moving pictures, and an editing machine for broadcast use.

10-mm-thick head mechanism for a stacked optical disk system

A 10-mm-thick head mechanism for a 30 GB, multi-head type stacked optical disk system has been developed. A pair of linear brushless motors are utilized as the coarse actuator, and a 2D motion lens actuator is utilized as the fine one. The average access time is 150 ms. The track following characteristics are tested. The tracking error is 0.03 micrometers in amplitude with a 3600 rpm, 254 mm diameter disk.

Optical system for high-throughput EUV lithography

The designed optical system, which included an illumination optics and an imaging optics, consists of only one grazing-incidence mirror and a two-aspheric-mirror optics with a synchrotron radiation (SR) as a light-source. The illumination optics provides uniform illumination and high-collection efficiency of radiation from the SR. Since there are only four bounces in this system, including the reflective-mask bounce, this optical system has higher throughput. A throughput of 20-30 wafers/hour is predicted with the designed optics. A one- quarter-size prototype of the designed imaging optics was constructed with the numerical aperture of 0.1 and the magnification of 1/5. The efficiency of 60 percent (obtaining dose per estimated one) was obtained with AZ-PN 100 resist in the experiment. A minimum pattern of 0.12-micrometers lines and spaces was printed on a 0.15-micrometers -thick layer of AZ-PN 100 resist.

In-position optical surface measurement for x-ray projection lithography optics: theory and simulation

A technique is proposed to measure x-ray projection optics. Simultaneous linear equations are derived from the wavefront distortions to obtain form errors of optical surfaces discretely. Simulations proved that the arithmetic operation errors are small enough to achieve nanometer level accuracy. This technique is effective to test aspheric reflectors, as well as the reflector misalignments. It also is able to be applied to adaptive optics compensating for thermal deformation effects or drifts on the exposure system.

Reflection Coefficient Correction Technique for an Optical Fiber Displacement Sensor

This paper presents a novel reflection coefficient correction technique for an optical fiber displacement sensor. The new technique uses conventional fiber prove, however, displacement signal and reflection coefficient signal are simultaneously detected with it, where illumination fiber functions for both irradiating a target plane and detecting reflection light from the target. An experimental setup consists of commercially available fiber prove and a laser diode was bulit, and it was found that measuring error was less than 0.05 μm even in case of target reflection coefficient changing from 40% to 95%. In this paper, measuring principle and design method for the optical system are described, also, some experimental results are discussed.