Abstract: A gas jet shooting device for use with a non-contact tonometer, having a hollow head (19) with a nozzle (27) secured thereto, a cylinder (10) which communicates with the head, and a piston (11) reciprocatably mounted in the cylinder and defining a compression chamber (14) in the cylinder, and a linear d.c. motor (31) for driving the piston (11) for compressing the gas in the cylinder (10), the compressed gas being allowed to issue through the nozzle. The cylinder (10) is fed with the gas through a passage which opens into the chamber (14) and which does not include the nozzle. The gas may be air, and drawn into or pushed into the chamber through a filter (F). It may also be a gas other than air, harmless to the eye, supplied from a reservoir through a filter. Such arrangement ensures that air-born dust or tear drops scattered by the air jet will not be drawn into the chamber, and the device can therefore be maintained hygienic.

Abstract: A noncontact type tonometer projects a fluid toward an eye-to-be-tested and obtains a measured value of eye pressure from a relation between transfigurations of the eye due to the fluid projection and the pressure projecting of the fluid. A detecting circuit senses a pulse wave of the person-to-be-tested and a calculating circuit determines at least one of the maximum eye pressure value, minimum eye pressure value and average pressure value of the eye dependent on the maximum fluctuation width of the detected pulse wave, a fluctuating quantity of the detected pulse wave, and the measured eye pressure value. The calculation circuit determines the pulse wave fluctuating quantity at the time point when the eye pressure is measured. The pulse wave of the person may be measured at a position remote from the eye. The tonometer may also include a display for displaying the pulse wave and a display controller for displaying the time point when the eye pressure is measured.

Abstract: A binocular microscope has an objective optical system for receiving a beam of rays from an object and emitting it as a parallel pencil of rays, a relay optical system for relaying the beam of rays coming from the objective optical system, and an ocular for receiving the beam of rays coming from the relay optical system. The binocular microscope is characterized in that the objective optical system is stored in a stationary housing portion, the relay optical system and the ocular optical system are stored in a movable housing portion disposed on the stationary housing portion, and there is provided means for moving the movable housing portion with respect to the stationary housing portion within a predetermined range in a plane perpendicular to an optical axis of the objective optical system stored in the stationary housing portion.

Abstract: An optical distance measuring apparatus having measurement error compensating function for compensating the measurement error due to electromagnetic induction noise which would lower the accuracy in distance measurement. According to the optical distance measuring apparatus of the present invention, the distance from the apparatus to the target is given by the difference in optical path between an "external optical path" to a corner-cube prism, i.e. the external target, and an "internal reference optical path". The measurement error can be cancelled by the periodicity of the measurement error curve and the predetermined length of the optical path extension means. Thus the measurement error can be compensated for and therefore a measured distance value free of measurement error can be obtained from the distance measuring apparatus.

Abstract: An air-puff tonometer, in which a puff of compressed air is blown out through a nozzle (N) toward the cornea of a subject eye (H), said compressed air being produced by energizing with an electric current a piston drive, which when thus driven compresses the air within a cylinder (5) in which the piston is mounted. The tonometer is provided with: pressure detector (11) for detecting the pressure within the cylinder (5); and current control (12, 14) for comparing a pressure signal (Vp) outputted from said pressure detector (11) with a predetermined reference signal (Vt) and for controlling the current supplied to said piston drive in such a manner that the difference between said pressure signal and said reference signal will be reduced.The air-puff tonometer so constructed will allow air within the cylinder thereof to be compressed in accordance with a predetermined pressure-time characteristic curve in spite of any change occurring in the clearance between the piston and the cylinder walls.

Abstract: A distance between a mask and a wafer is set such that exposure light beams emerged from the mask are converged by the projection lens to be focused on the wafer. Two light beams with same wavelength of the alignment light beam emerge from a first point (b) which is located far away from the mask, and are focused on the wafer or neighborhood of it by the projection lens. Two mask marks of diffraction gratings are formed on the mask and spaced at a predetermined distance from each other. When the alignment light beams are applied to the mask marks, two diffracted light beams of predetermined order emerge individually from the mask marks in such a manner that the respective optical axes of the two diffracted light beams, which are directed oppositely to of the diffracted light beams, intersect each other on the first point. Thus, the diffracted light beams advance as if the diffracted light beams were the two light beams emerging from the first point.

Abstract: A non-contact type tonometer is disclosed. It has an arrangement for transfiguring a cornea to be tested by discharging a fluid to it. This first arrangement comprises a rotary solenoid, a cylinder, and a rotary solenoid driving circuit. It also has a second arrangement for detecting the physical quantity showing the transfiguration of the cornea. The second arrangement comprises a radiating optical system and a detecting optical system. It also has a circuit serving as a third arrangement for detecting the flow pressure of the fluid which has a correlation with an intraocular pressure. It has a fourth arrangement for establishing a correlation function curve between the physical quantity and the flow pressure of the fluid based on the information from the second and third arrangements, deducing a flow pressure value corresponding to the preset value of the physical quantity from the correlation function curve, and converting such deduced flow pressure value of the fluid to an intraocular pressure value.

Abstract: 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).

Abstract: A light detector is disclosed which comprises a light-receiving section adapted to receive a measuring light beam at a front face thereof and to photoelectrically convert the light beam thus received and a display section adapted to display a measurement result on the basis of an output from the light-receiving section. The display section is constituted by a pair of display segments each having at least one displaying face on a respective one of side faces which are formed on opposed sides of the light-receiving section sandwiching it therebetween and are inclined with respect to the front face in such a direction that back faces thereof approach to each other.

Abstract: An illuminating system of an ophthalmological instrument has a coaxial illuminating system for effecting a coaxial illumination by projecting an observation-use illuminating light toward an eye to be tested from a direction generally parallel with an optical axis of through an objective lens of an observing optical system, FIGS. 1A and 1B each illustrated an oblique illuminating system branched from the coaxial illuminating system and adapted to effect an oblique illumination by projecting the observation-use illuminating light toward the eye from an oblique direction different from the coaxial illumination, and an optical path switching optical member disposed in an intermediate part of an optical path of the coaxial illuminating system and adapted to switch the coaxial illumination to the oblique illumination or vice versa.

Abstract: A code reader comprising a scanner portion including an illuminating light source for illuminating a code in which all data are separated into at least two parts. A first partial code pattern and a second partial code pattern and a plurality of discriminating elements are arranged as such that the first and the second partial code patterns can be distinguished. A light receiving portion for receiving a reflection light reflected by the code, and a binary processing portion for binating an output signal of the light receiving portion; and a decode portion for decoding the binary signal for each partial code data based on an output of the binary processing portion.

Abstract: A distance between a mask and a wafer is set such that exposure light beams emerged from the mask are converged by the projection lens to be focused on the wafer. According to the present invention, two mask marks of diffraction gratings are formed on the mask and spaced at a predetermined distance from each other. When the alignment light beams are applied to the mask marks, two diffracted light beams of predetermined order emerge individually from the mask marks in such a manner that the respective optical axes of the two diffracted light beams, which are directed opposite to the advancing direction of the diffracted light beams, intersect each other one the first point. Thus, the diffracted light beams advance as if the diffracted light beams were the two light beams emerging from the first point. Therefore, the two diffracted light beams can be focused on the wafer or neighborhood of it. The diffracted light beams can be incident on a wafer mark which is formed on the wafer and is diffraction grating.

Abstract: A noncontact type tonometer includes a fluid discharging device for discharging a fluid towards the cornea of an eye to be tested; an alignment detecting device for detecting an alignment between the axis of a fluid discharge of the fluid discharging device and the vertex of the cornea and for outputting an alignment signal; and a controlling device for determining whether or not the alignment has been completed upon receipt of the alignment signal from the alignment detecting device and outputting an alignment completion signal when the alignment has been completed. A fluid discharge of the fluid discharging device is automatically performed based on the alignment completion signal.

Abstract: An eye testing apparatus, in which a cornea reflecting image and a retina reflecting image formed by projecting each target mark image onto a cornea and a retina of an eye to be tested are projected to a slight receiving portion through a measuring optical system, and in which a corneal configuration and a refractive power of the eye to be tested are measured according to a signal detected by the light receiving portion, characterized in that the light receiving portion includes a two-dimensional light receiving element, the measuring optical system simultaneously projecting the cornea reflecting image and the retina reflecting image to different areas of the two-dimensional light receiving element.

Abstract: A coordinates measuring apparatus comprising a detecting unit constituted by an optical system for obtaining an image of an object and a detecting system having a plurality of arrayed detecting elements disposed in such a manner that respective detecting signals are superposed at the position of said image, a control unit for taking out data from each of said arrayed detecting elements, and a storage unit for storing the data of each array taken out from said control unit.

Abstract: A light source device for use in a medical apparatus has a turnable or linearly movable member or flange provided in a housing, and an actuator removably attached to the movable flange and carrying two light sources thereon. The actuator has two connector plugs provided thereon which are connected to the two light sources respectively, while the movable member is provided with two corresponding connector sockets. The two connector plugs and the corresponding two connector sockets are coupled and separated together when the actuator and the movable member are coupled and separated together. The device further comprises light conductor means for guiding light from one of the light sources to an object to be illuminated, and switch means connected between a power source and each connector socket. The device is arranged such that one of the two light sources is positioned opposite to the inlet of the light conductor means by moving the movable member coupled with the actuator.

Abstract: A laser beam scanning type eye fundus camera has a laser beam generator for generating a laser beam; an illuminating system for illuminating the fundus of an eye to be tested by scanning the laser beam generated by the laser beam generator on the eye fundus; a first and a second light receiving portions for receiving a reflecting light of the laser beam reflected by the eye fundus; a first light receiving system for guiding the reflecting light of the laser beam reflected by the eye fundus to the first light receiving portion; a second light receiving system for guiding a fluorescence excited at the eye fundus by the laser beam; and an electronic circuit for forming an eye fundus image on a monitor TV according to an output signal coming from the first and second light receiving portions.

Abstract: There is disclosed an automatic eye refractive power measuring apparatus for automatically measuring refractive power of an eye under test by means of objective measurement.

Abstract: According to this invention, a method and apparatus for aligning a mask and a wafer arranged to oppose each other, in a direction along their opposing surfaces, relative to each other, are arranged as follows. A first diffraction grating as a one-dimensional diffraction grating, bars of which extend in a direction perpendicular to an alignment direction, is formed on the mask. A second diffraction grating which has a checkerboard-like pattern, is formed on the wafer. The first diffraction grating is irradiated with laser beam emitted from a light source. Light beams diffracted and transmitted through the first diffraction grating is transferred to the second diffraction grating. Light beams diffracted and reflected by said second diffraction grating are transferred to said first diffraction grating. The light beams are diffracted by and transmitted through said first diffraction grating, again. Is detected, one of the diffracted light beams, which do not propagate along a predetermined plane.

Abstract: An optical system for a retinal camera comprises objective lens adapted to be located toward a patient's eye. The retina of the patient's eye is illuminated and photographed through the objective lens, which has a first biconvex type lens means and a second biconvex type lens means with a space between them, the first biconvex type lens means has a curvature radius of the first convex surface open to the air and faces toward the eye of which is larger than that of the other second convex surfaces open to the air, and the second biconvex type lens means of which curvature radius of third convex surface open to the air and facing toward the first biconvex type lens means is larger than that of the other fourth convex surfaces open to the air.