Abstract: An endoscope observation optical system capable of improving the observation resolution of a mucous membrane of a living body is provided. The endoscope includes an observation optical system compatible with both standard visible-light observation and blood-vessel-enhancement observation, whose main component of a displayed image is an absorption peak of hemoglobin present in a waveband lower than 480 nm, wherein some longitudinal chromatic aberration remains in the endoscope observation optical system due to undercorrection at a wavelength of 415 nm, and wherein the focal position during blood-vessel-enhancement observation is set closer to a near point than the focal position during standard visible-light observation.

Abstract: An image pickup apparatus having two image sensors includes two solid state image pickup devices and a prism group that includes a color separation coating that reflects green light. Red and blue transmitting “on chip” color filters are supported on one of the two solid state image pickup devices. The image pickup apparatus has a spectral design to control color shading in changing environments, and is also designed for easy assembly. The spectral design requires that the spectral transmission characteristics of the color separation coating, the red and blue transmitting color filters, and the spectral sensitivity characteristics of pixels of the solid state image pickup devices satisfy certain conditions that pertain to boundaries between the red, blue, and green light. Image readout is provided by combining two adjacent pixels of the image field. A method of manufacturing such an image pickup apparatus is also disclosed.

Abstract: A magnetic resonance imaging apparatus of the invention comprises a static magnetic field generation unit which generates a static magnetic field in a gantry, a gradient magnetic field generation unit which applies a gradient magnetic field to a object in the static magnetic field, a radio frequency coil which receives a magnetic resonance signal from the object to which the gradient magnetic field is applied, a contour detection unit which detects a contour of the object, a coil movement unit which moves the radio frequency coil on the basis of the detected contour while the radio frequency coil is placed near and far relative to the object, and an image generation unit which generates a magnetic resonance image on the basis of the received magnetic resonance signal.

Abstract: A magnetic resonance imaging apparatus of the invention comprises a static magnetic field generation unit which generates a static magnetic field in a gantry, a gradient magnetic field generation unit which applies a gradient magnetic field to a object in the static magnetic field, a radio frequency coil which receives a magnetic resonance signal from the object to which the gradient magnetic field is applied, a contour detection unit which detects a contour of the object, a coil movement unit which moves the radio frequency coil on the basis of the detected contour while the radio frequency coil is placed near and far relative to the object, and an image generation unit which generates a magnetic resonance image on the basis of the received magnetic resonance signal.

Abstract: An optical system pair for a stereo endoscope is described which enables adjustment of magnification matching in the production phase with low cost and small size for the resulting stereo endoscope products. The stereo optical systempair for stereo endoscope system includes a right optical system and a left optical system, wherein one of the right and left optical systems includes a lens group which has a refractive power, and which is designed to be moveable axially with a moveable range and has a position within the moveable range at which optical magnification equals to ?1. Also described are optical arrangements of a stereo endoscope incorporating the stereo optical system pair.

Abstract: A washable air filter for an internal combustion engine which has high durability and can be washed with ease to reuse it is disclosed. The washable air filter includes an outer cylindrical member 10; an inner cylindrical member 11; a first filter element 30 formed from a stainless mesh sheet which is folded in a pleated-form having peaks and valleys arranged alternately and provided between the outer cylindrical member 10 and the inner cylindrical member 11; and a second filter element 33 provided between the outer cylindrical member 10 and the first tilter element 30. Since the washable air filter uses the filter element made from the stainless mesh sheet, it is possible to effectively remove dust particles from air. Further, the washable air filter can be reused because dust particles are removed off the filter element by washing after use.

Abstract: An optical system pair for a stereo endoscope is described which enables adjustment of magnification matching in the production phase with low cost and small size for the resulting stereo endoscope products. The stereo optical system pair for stereo endoscope system includes a right optical system and a left optical system, wherein one of the right and left optical systems includes a lens group which has a refractive power, and which is designed to be moveable axially with a moveable range and has a position within the moveable range at which optical magnification equals to −1. Also described are optical arrangements of a stereo endoscope incorporating the stereo optical system pair.

Abstract: A washable air filter for an internal combustion engine which has high durability and can be washed with ease to reuse it is disclosed. The washable air filter includes an outer cylindrical member 10; an inner cylindrical member 11; a first filter element 30 formed from a stainless mesh sheet which is folded in a pleated-form having peaks and valleys arranged alternately and provided between the outer cylindrical member 10 and the inner cylindrical member 11; and a second filter element 33 provided between the outer cylindrical member 10 and the first tilter element 30. Since the washable air filter uses the filter element made from the stainless mesh sheet, it is possible to effectively remove dust particles from air. Further, the washable air filter can be reused because dust particles are removed off the filter element by washing after use.

Abstract: A stereo endoscope having right and left optical systems for stereoscopic observation which form the right and left images, respectively. The stereo endoscope further including a third optical system which has a wider field of view and a smaller maximum lens diameter than the right and left optical systems.

Abstract: A rigid endoscope optical system which can obtain both a wide angle image for finding an organ and a high resolution image used for a precise treatment. The rigid endoscope optical system has objective optical systems for stereoscopic observation which forms right and left images. The rigid endoscope optical system also has a secondary objective optical system which has a field of view different from the objective optical system for stereoscopic observation, and one relay optical system which transmits the images of the objective optical system for stereoscopic observation and the secondary objective optical system.

Abstract: A stereo endoscope having right and left optical systems for stereoscopic observation which form the right and left images, respectively. The stereo endoscope further including a third optical system which has a wider field of view and a smaller maximum lens diameter than the right and left optical systems.

Abstract: A field conversion system for rigid endoscopes has a rigid endoscope inserted into an object to form an optical image of the object and an imaging device connected to the rigid endoscope. The imaging device includes an imaging optical system for changing the magnification of the optical image to form a resultant image and an image sensor placed at the position of an imaging plane produced by the imaging optical system. A part or a whole of the imaging optical system or the image sensor is moved in a direction perpendicular to an optical system, thereby carrying out a field conversion. The field conversion system is provided with a time-division shutter mechanism placed close to a pupil position inside the imaging optical system so that two light beams at different positions in a pupil are switched time-dividedly and transmitted and the image sensor picks up time-dividedly left and right images with parallax.

Abstract: The impurity concentration contained in a layer on an electron supply layer of a high electron mobility field effect transistor is set in the range of 1˜1016 to 1˜1017 atoms/cm3, or the bandgap of a Schottky layer is set wider than that of the electron supply layer. Otherwise, in the steps of manufacturing the high electron mobility field effect transistor, after a silicon nitride film has been formed on a GaAs buried layer in which a second recess is formed and in a region on the inside of a first recess formed in a GaAs contact layer, the GaAs buried layer is still heated.

Abstract: The impurity concentration contained in a layer on an electron supply layer of a high electron mobility field effect transistor is set in the range of 1×1016 to 1×1017 atoms/cm3, or the bandgap of a Schottky layer is set wider than that of the electron supply layer. Otherwise, in the steps of manufacturing the high electron mobility field effect transistor, after a silicon nitride film has been formed on a GaAs buried layer in which a second recess is formed and in a region on the inside of a first recess formed in a GaAs contact layer, the GaAs buried layer is still heated.

Abstract: The impurity concentration contained in a layer on an electron supply layer of a high electron mobility field effect transistor is set in the range of 1×1016 to 1×1017 atoms/cm3, or the bandgap of a Schottky layer is set wider than that of the electron supply layer.

Abstract: A relay lens system used in an observation optical system which is to be disposed in an insert section is disclosed. The relay lens system comprises a plurality of relay lens units at least one of which allows longitudinal chromatic aberration to remain in an undercorrected tendency and at least another of which allows longitudinal chromatic aberration to remain in an overcorrected tendency, thereby correcting longitudinal chromatic aberration favorably in the relay lens system as a whole.

Abstract: A field conversion system for rigid endoscopes has a rigid endoscope inserted into an object to form an optical image of the object and an imaging device connected to the rigid endoscope. The imaging device includes an imaging optical system for changing the magnification of the optical image to form a resultant image and an image sensor placed at the position of an imaging plane produced by the imaging optical system. The imaging optical system or the image sensor is moved in a direction perpendicular to the optical axis, thereby carrying out a field conversion. The rigid endoscope include an objective optical system, a relay optical system, and an eyepiece optical system. The field conversion system satisfies the following conditions:0.6.ltoreq.Dm.vertline.fw/foc.vertline./Lc.ltoreq.1.21.6.ltoreq.Dm.vertline.ft/foc.vertline./Lc.ltoreq.

Abstract: A relay lens system used in an observation optical system which is to be disposed in an insert section is disclosed. The relay lens system comprises a plurality of relay lens units at least one of which allows longitudinal chromatic aberration to remain in an undercorrected tendency and at least another of which allows longitudinal chromatic aberration to remain in an overcorrected tendency, thereby correcting longitudinal chromatic aberration favorably in the relay lens system as a whole.

Abstract: A non-flexible endoscope comprising a slender insert section which is to be inserted from a leading end thereof into cavities of living bodies and the like for observing interiors thereof, and comprises an observation optical system consisting only of an objective lens system for forming a primary image in the vicinity of an end opposite to the leading end. The non-flexible endoscope comprises an optical system which is composed of a small number of lens elements and is bright, and can be manufactured at a low cost.

Abstract: In a non-flexible endoscope consisting of an insertion section and an eyepiece section which are separable from each other, an optical system configured so as to correct chromatic aberration produced by an observation optical system disposed in the insertion section with an eyepiece optical system disposed in the eyepiece section. The optical system according to the present invention selects a simple composition for the observation optical system so that it is manufacturable at a low cost and disposable, and is configured so as to have favorable optical performance as a whole by correcting chromatic aberration produced by the observation optical system with the eyepiece optical system.