Kabushiki Kaisha Topcon

Tokyo Kogaku Kikai Kabushiki Kaisha

Kabushiki Kaisha Toshiba

Hiroaki Shimozono

Takashi Yokokura

Nobuo Hori

Satoru Niimura

Toru Tojo

Ryoichi Hirano

Mitsuo Tabata

Norio Uchida

Yoriyuki Ishibashi

Masayuki Masuyama

A measuring apparatus has a model eye for measuring a distance from a first objective surface to a second objective surface, an observation optical system for observing an interference between reflected light flux from the model eye and reflected light flux from the object eye, and a light flux split member for splitting light flux and guiding coherent split light flux to both the object eye and the model eye. The model eye is provided with at least a first surface corresponding to the first objective surface and a second surface corresponding to the second objective surface. The interference fringe between the first surface and the first objective surface being observed, and the interference fringe between the second surface and the second objective surface is in order to measure the length of a visual line as a distance from the first objective surface to the second objective surface (eye axial length), the depth of the anterior chamber, the thickness of a crystal lens, etc.

Apparatus for measuring length of visual line length, depth of anterior

A light wave range finder has a range finding optical system in which the intensity of a coherent beam of light emitted from a coherent light source is modulated and delivered to an object and a reflecting beam of light reflected on the object is received by an light receiving element. A distance to the object is measured based on a phase detection of the reflecting beam of light. The range finding optical system has an optical substrate which is provided with, at least, a light intensity modulating portion for modulating the intensity of a coherent beam of light; an optical path changing portion for changing the coherent beam of light, which has been modulated the intensity by the light intensity modulating portion, between an external range finding optical path and a reference optical path; a first light amount regulating portion for regulating a light amount of the coherent beam of light guided to the external range finding optical path; a delivering system for delivering the coherent beam of light which has been regulated the light amount of the first light amount regulating portion toward an object; and a light receiving system for receiving a reflecting beam of light reflected by the object.

Light wave range finder

A range finder for finding a distance to an object comprising an outgoing light guiding wave path, a reference light guiding wave path, and an incoming light guiding wave path. The finder further comprises wavelength changing means for changing the wavelength of the beam of light emitted from the light source, wavelength detecting means for detecting the wavelength of the beam of light emitted from the light source, and calculating means for detecting at least two peaks of the signal coming from the light receiving element when the wavelength of the light source is changed by the wavelength changing means, finding the wavelengths of the light source, respectively, from the wavelength detecting means at the time when the signal exhibits the two peaks, and calculating the distance to the object according to an operation expression memorized beforehand with reference to such obtained two wavelengths. A total reflection prism, a polarized beam splitter, a quarter-wave plate, and a mode converting device are also provided.

Method and apparatus for finding range

An integrated-photocircuit interferometer (20) comprises a substrate (21) in which coherent light for measurement emitted from a light source (23) is directed through an exit waveguide (22) toward a corner cube prism (34) which can be movable with an object to be measured. The light reflected back from the prism (34) can enter an inlet waveguide (33) having branch waveguides (35, 36) which split the incident measurement light. Part of the light transmitted through the exit waveguide (22) is transferred to reference waveguides (26, 27) which provide different optical path lengths for the light propagated therethrough. The 'reference beams of light' which has been transmitted through the different lengths of optical paths provided by the reference waveguides (26, 27) are introduced into the branch waveguides (35, 36) where interference occurs between the reference beams and the split beams of incident light from the corner cube prism (34). The interference will cause changes in brightness detected by photodetectors (37, 38) as the prism (34) is shifted toward or away from the interferometer (20). Since there is an optical path length difference between the reference waveguides (26, 27), a great number of changes can be detected by the photodetectors for a shift of the prism. Thus, the amount of the shift can be determined to a high resolution. In addition, the relationship in phase between the detected brightnesses will change depending on the direction of movement of the corner cube prism (34). The direction of the prism's movement can thus be detected.

Integrated-photocircuit interferometer

A light interferometer has an interferometer portion for interfering a measuring light and a reference light, and a light signal processing portion for processing a signal according to an interference signal which changes according to the change of an optical path length of the measuring light. The interferometer portion has a first light source for generating a coherent light, a light interference portion for dividing the coherent light emitted by the first light source into a reference light and a measuring light in order to introduce the measuring light to an object, making the measuring light reflected by the object and the reference light interfered with each other and introducing thereof to a photo detector, and an optical path length periodically changing means for periodically changing the difference of an optical path length of the reference light with respect to the optical path length of the measuring light relatively at a constant amplitude. The light signal processing portion has a second light source for generating a coherent light, a collimate lens portion for collimating the coherent light emitted by the second light source, a space modulating portion for diffracting the coherent light outgoing from the collimate lens portion, a Fourier transforming portion for transforming the diffracted coherent light, and two photodetectors disposed on at a spot corresponding to a frequency composition equivalent to a frequency of the optical path length periodically changing means and the other at a spot corresponding to a frequency composition two times the first-mentioned frequency composition in order to extract these frequency compositions out of frequency compositions which have been decomposed in frequency spectral by the Fourier transforming portion.

Light interferometer

According to this invention, a method and apparatus for setting a gap to a predetermined distance between a mask and a wafer facing each other, are arranged as follows. First and second diffraction grating are formed on a mask and a wafer. The first diffraction grating is one-dimensional type and has parallel bars extending in a predetermined direction. The second diffraction grating is one-dimensional type and has parallel bars extending in a direction perpendicular to the predetermined direction. The second diffraction grating may be two-dimensional type having cross-bars. Laser beam is radiated from a light source onto the first diffraction grating. The light beams diffracted and transmitted through the first diffraction grating are transferred to the second diffraction grating. The light beams diffracted and reflected by the second diffraction grating are transferred to the first diffraction grating. The light beams are diffracted and transmitted through the first diffraction grating. Is detected, one of the diffracted light beams which are not oriented along a predetermined. The light beams reflected and diffracted by the surface of the first diffraction grating is transferred only by the prdetermined plane. Therefore, detected and diffracted light beam does not interfere with reflected light beams. The gap between the mask and the wafer can be adjusted and can be set to a predetermined distance.

Method and apparatus for setting a gap between first and second objects

In a method for aligning first and second objects relative to each other, according to this invention, the first and second objects are arranged opposite to each other, and are aligned in a direction perpendicular to their opposing direction. A grating pattern is formed, as an alignment mark, on the first object, and a checkerboard-like grating pattern is formed, also as an alignment mark, on the second object. A light beam emitted from an alignment light source is radiated onto the checkerboard-like grating pattern of the second object. The light beam diffracted by the checkerboard-like grating pattern is guided onto the grating pattern of the first object. The light beam diffracted by the grating pattern of the first object is detected by a detector. Since the light beam emitted from the light source is diffracted by the checkerboard-like grating pattern, a relative position of the first and second objects can be detected, irrespective of the distance therebetween. The first and second objects are accurately aligned, based on the detection result. This invention can be applied to a method for aligning a mask and a wafer when a circuit pattern pre-formed on the mask is to be transferred onto the wafer.

Growing community of inventors

Tokyo, Japan

Hiroaki Shimozono