Abstract: A range finder 100 includes a transmission optical system 20 that transmits signal light toward a target object, a detection optical system 30 that has a different optical axis from that of the transmission optical system and detects the signal light reflected from the target object, and a photodetector 12 that is disposed on an imaging surface of the detection optical system. A distance to the target object is measured on the basis of a time difference between a transmission time and a detection time of the signal light. The detection optical system 30 includes a variable focal length optical system 14 that makes the focal length of the detection optical system variable, thereby providing a range finder capable of measuring a distance to a target object that locates from further away to nearer by using a photodetector having the same size.

Abstract: A telescope 110 includes: a single objective optical system 113; and a binocular body member (111, 112); the binocular body member including a mount portion 116 for connecting to the objective optical system 113, and a controller 114 for controlling the objective optical system, thereby providing a telescope capable of making binocular observation of an image of an object formed by a single objective lens.

Abstract: A telescope 110 includes: a single objective optical system 113; and a binocular body member (111, 112); the binocular body member including a mount portion 116 for connecting to the objective optical system 113, and a controller 114 for controlling the objective optical system, thereby providing a telescope capable of making binocular observation of an image of an object formed by a single objective lens.

Abstract: A range finder 100 includes a transmission optical system 20 that transmits signal light toward a target object, a detection optical system 30 that has a different optical axis from that of the transmission optical system and detects the signal light reflected from the target object, and a photodetector 12 that is disposed on an imaging surface of the detection optical system. A distance to the target object is measured on the basis of a time difference between a transmission time and a detection time of the signal light. The detection optical system 30 includes a variable focal length optical system 14 that makes the focal length of the detection optical system variable, thereby providing a range finder capable of measuring a distance to a target object that locates from further away to nearer by using a photodetector having the same size.

Abstract: An input matching circuit is provided having the output impedance-frequency characteristics wherein the output impedance shows a value approximately equal to that of the gate input impedance of the FET at the frequency of the objective signal to be amplified, and the output impedance shows a value not more than twice the gate input impedance of the FET at least at the entire frequencies from the frequency of the objective signal to be amplified through twice the frequency of the objective signal to be amplified so that the matching between the input previous stage circuit and the gate of the FET can be secured. Thereby, a high-frequency power amplifier circuit and a high-frequency power amplifier module, which can suppress the occurrence of distortion, perform stably, and get miniaturized, are configured.

Abstract: An anti-vibration telescope allows an image formed on the retina of the observer's eye to remain stationary even when the telescope is tilted from its original position. The anti-vibration telescope includes an objective lens which has an anti-vibration optical element for compensating for image fluctuation. An eyepiece is provided for enlarging the image formed by the objective lens with help of the anti-vibration optical element. The anti-vibration optical element is controlled so that when the telescope is tilted by an angle .epsilon. from an originally focused position, the image point is shifted in the focal plane of the objective lens by an amount .delta. which lies within the rangef.sub.o .epsilon.<.delta.<(f.sub.o +2f.sub.e).epsilon.where f.sub.o is a focal length of the objective lens and f.sub.e is a focal length of the eyepiece.

Abstract: A compact ophthalmoscopic camera illumination apparatus with which a bright eyeground image can be obtained even for high magnification photography. The camera includes an annular flux forming means that has an entering end (22A) positioned in a vicinity of a light source image, an annular emitting end (22D), a cone-shaped outer reflective surface (22B), and a cone-shaped inner reflective surface (22C); wherein illumination light entering the entering end is reflected on the outer reflective surface and the inner reflective surface, guided to the emitting end, and exits as annular flux from the emitting end. The annular flux passes through the objective lens (1) to form an annular illumination area in the vicinity of the pupil (20) of the patient's eye.

Abstract: This invention provides a microscope for operation which can form a black point for protecting a patient's retina even when the retina part is not at the center of the field of view of the microscope. The microscope for operation has an X-Y stage for moving the microscope body, a CCD camera for obtaining an image in the field of view of the microscope, a liquid crystal device provided with a light transmitting surface transmitting illuminating light therethrough and comprised of display dots disposed in the form of a matrix, and a control device for controlling and driving the liquid crystal device.

Abstract: An auxiliary instrument for observing a fundus of eye, comprises an ophthalmic lens for forming an image of light beam reflected by the fundus of an examined eye, a lens holding member for holding the ophthalmic lens, a frame mounted with the lens holding member and put on the head or a part of the face of an examinee so that the ophthalmic lens is located in front of the examined eye of the examinee, and an inclination mechanism, provided between the lens holding member and the frame, for inclining an optical axis of the ophthalmic lens at a predetermined angle to an optical axis of the examined eye.

Abstract: The invention provides an ophthalmological illumination device which produces a plurality of illumination types using a single light source. The device illuminates the examined eye without causing damage to the maculalutea of the retina. The device illuminates the examined eye through an object lens and includes a light source means for supplying illumination light and a light separating means for separating the illumination light. The light separating means separates the light into a first illumination light which is incident on the object lens in a direction parallel with the optical axis of the object lens and a second illumination light. A movable inclining means causes the second illumination light to be incident on the object lens in a direction parallel with the optical axis. The angle of the second illumination light incident on the examined eye changes relative to the optical axis in accordance with the movement of the movable inclining means.

Abstract: A compact internal focus objective lens system utilized in an astronomical telescope, tenestrical telescope, photo lens or the like has a superior ability to compose images when focusing on close or near objects. The lens system includes, in order from the object side, a first lens group G1 with a positive refractory power and a second lens group G2 with a negative refractory power. The first lens group G1 includes a composite lens L1 with a negative lens L11 and a positive lens L12 and a single lens L2 with a positive refractory power. The second lens group G2 has a composite lens L3 that has an overall negative refractory power. The second lens group G2 is moved along the optical axis for focusing. The objective lens satisfies the following conditions, thus permitting the compact internal focus objective lens system to clearly compose images, when focusing on close or near objects:0.3<f1/F<0.6-0.5<f2/F<-0.20.15<r4/F<0.35-1.5<(r6+r8)/(r6-r8)<1.50.15<r2/F<0.440<.nu.

Abstract: An aspherical eyepiece has a positive lens group and a correction plate positioned on the light incident side of the positive lens group and having an aspherical surface. The correction plate is positioned between the positive lens group and the front side focal plane of the positive lens group or in front of the front side focal plane of the positive lens group. Thus, although the eyepiece is constructed by a reduced number of optical members including an aspherical optical member, distortion can be favorably corrected even with a wide field angle.

Abstract: An ophthalmic illumination apparatus for illuminating an eye to be examined with light comprises a light source emitting illuminating light, shading means including an electrical light control element of which the transmittance is electrically varied and shading at least part of the illuminating light, and control means for electrically varying the transmittance of the shading means.

Abstract: An ophthalmic optical apparatus having an alignment optical system comprises two conical optical elements for forming an alignment light beam into a ring-shaped collimated light beam centered on an optical axis and directing it to a focusing optical system, an in-focus state is determined based on a light pattern formed by the focusing optical system from the ring-shaped collimated light beam on an object plane.

Abstract: An eyepiece lens system having an apparent field of view more than 60.degree. and an eye relief greater than 80% of the total focal length of itself comprises a first lens group, a second lens group disposed rearwardly of the first lens group and a third lens group disposed rearwardly of the second lens group. The first lens group includes a positive meniscus lens component with its convex surface facing rearward, the second lens group includes a cemented positive doublet lens component consisting of a biconvex lens element and a negative meniscus lens element, and the third lens group includes at least a positive meniscus lens component with its convex surface facing forward. The eyepiece lens system satisfies predetermined optical conditions.