Abstract: An illumination control system comprises a rotation detecting section, an abnormality determination section, and a filter removing section. The rotation detecting section detects the rotational driving of a filter which is located on a path of illumination light emitted from a light source, which irradiates color light rays having different wavelengths to an object, and which is driven by a rotational driver. The abnormality determination section determines whether status of filter rotation is normal or abnormal based on the detected rotation of the filter by the rotation detecting section. The filter removing section removes the filter from the path of the illumination light when the abnormality determination section determines that the status of filter rotation is abnormal.

Abstract: In a light source unit, a switchable filter section in which an RGB filter and a fluorescence observation filter can be shifted into the light path is disposed in front of a lamp. When fluorescence image mode is selected, excitation light in a part of the wavelength band of the blue wavelength band is supplied to an electronic endoscope, and the excitation light which is reflected by the subject is shielded by an excitation light shielding filter situated in front of a CCD, whereby a fluorescence image can be obtained. On the other hand, if normal-light image mode is selected, then R, G, B light is supplied sequentially, and even under illumination of B light, the color component image in the wavelength bands which are not shielded by the excitation light shielding filter are captured, thereby yielding a normal-light image also, and hence making it possible to capture both a fluorescence image and a normal-light image by means of a single image pickup element.

Abstract: An aperture mechanism of this apparatus is provided with an aperture blade which has, for example, an outline converging toward the front end with a shielding width of the front-end blade section smaller than the diameter of a ray bundle transmitted into a light guide to achieve desired dimming by shielding the light in proximity of the central region in the ray bundle earlier than that in the outer regions. Thus, a relatively narrow distribution of light will be radiated onto an observed object for a long-distance examination of smaller aperture quantities and a wide distribution of illumination light will be radiated for a short-distance examination of larger aperture quantities. In addition, the aperture mechanism may be configured to move a small-circle aperture blade which is smaller than the cross-sectional area of the ray bundle disposed on the optical axis in the direction of optical axis to shield the light in proximity of the central region in the ray bundle earlier than that in the outer regions.

Abstract: An endoscope includes a red component cut optical filter having a characteristic that a spectral transmittance becomes half at 630 nm and zero at 670 nm, for example between a light source and an infrared cut filter, to remove a long wavelength component mainly in a red band of illumination light. This restrains scattering of light on a long wavelength side of red light, and allows taking images of mucosa, blood vessels, and other tissue in good contrast in an object to be observed and satisfactorily observing them on a monitor. Further, reduction in light amount resulting from cutting a red component with the filter is eliminated by light amount control with an aperture and gain control of a signal.

Abstract: An endoscope system comprising an endoscope which incorporates an imaging element together with an element for determining the type of the imaging element; a light source apparatus, which includes a DMD in a light path from a light source lamp, for determining incidence or non-incidence of the illuminating light from the light source lamp on a mirror; a CPU which determines the type of imaging element based on the information provided by the type determining element and detects a time required by the imaging element for charge reading based on the determination result; and a DMD control circuit which controls the DMD at a charge reading timing of the imaging element corresponding to the charge reading time detected by the CPU, the endoscope system making it possible to extend the exposure time to a maximum regardless of the type of the endoscope, by controlling the light shielding time of illuminating light in accordance with the type of the imaging element.

Abstract: An endoscope to perform non-tethered macroscopy and microscopy at the same time is provided. An electromagnetic source is used to deliver electromagnetic energy through a first optical pathway to a tissue inside a body. An image detector is used to detect the reflected electromagnetic energy from the tissue through a second optical pathway as real-time images. A macro-to-micro lens set is used to change the magnification of the reflected electromagnetic energy before it reaches the image detector with two or more different magnification levels. A filter set is used to filter the reflected electromagnetic energy before it reaches the image detector. Furthermore, the endoscope includes a flexible shaft. The distal end of the shaft includes a spread and spot means to spread and spot the electromagnetic energy at the tissue. A processing means is also included for processing the detected images.

Abstract: A fluorescence endoscopy video system includes a multimode light source that produces light for color and fluorescence imaging modes. Light from the light source is transmitted through an endoscope to the tissue under observation. The system also includes a compact camera for color and fluorescence imaging. Images obtained through the endoscope are optically divided and projected onto one or more image sensors by a fixed beam splitter in the camera. The fixed beam splitter eliminates the need for inserting a movable mirror into the light path between the endoscope and the image sensors. Image signals from the camera are processed in the system processor/controller where a contrast enhancement function can be applied. The contrast enhancement function increases the color contrast between normal tissue and tissue suspicious for early cancer. Finally, the system also includes a calibration feature whereby the system performance can be maintained when used with different endoscopes.

Abstract: A lighting system for an endoscope includes a lamp positioned so that an optical axis thereof is oriented horizontally; a light guide having an incident end upon which the illuminating light from the lamp is incident; a diaphragm plate rotated about a pivot so as to advance into and retract from an optical path of the illuminating light, the pivot extending parallel to the optical axis of the lamp and positioned above or below the optical path. The diaphragm plate includes a notch which is formed at one end of the diaphragm plate, the notch being positioned along an arc which is centered about the pivot and which intersects a center of the light guide when the diaphragm plate rotates about the pivot; and a large number of minute perforations formed along and below the arc.

Abstract: An endoscope observation system for in vivo cellular observation is disclosed that includes an illumination optical system having a light source for supplying illumination light to an object, an objective optical system that forms a magnified image of the object such that the absolute value of the image scale factor exceeds unity, and an image pickup unit that detects the magnified image. The illumination optical system is provided with a wavelength selection means for dividing, among the blue, green, and red wavelength ranges in the illumination light from the light source, either the blue wavelength range or the red wavelength range into two wavelength bands T1 and T2, with the wavelength band T1 being nearer the green wavelength range than is the wavelength band T2, and light in the wavelength band T1 is prevented from illuminating the object. An in vivo cellular observation method is also disclosed using an endoscope.

Abstract: An accurate determination of the tissue state of a diseased portion is performed by use of an image obtaining apparatus employing a charge multiplying type solid state image obtaining element. A target subject is irradiated with an illuminating light that contains an excitation light, and the reflected light, which includes a fluorescence image, reflected from the target subject thereupon is detected by a charge multiplying type CCD. At this time, the fluorescent light image is passed through a rotating filter, and is detected as a wide band fluorescent light image and a narrow band fluorescent light image by the charge multiplying type CCD, and obtained as a wide band fluorescence image data and a narrow band fluorescence image data by an image processing unit. A fluorescence diagnostic image is obtained of the wide band fluorescence image data and the narrow band fluorescence image data, and displayed on a monitor.

Abstract: An objective lens is substantially telecentric toward the image side, and provided with an ultraviolet cut coating on its rearmost surface. An imaging plane of a CCD is arranged near a position where an image of an object is formed through the objective lens. An ultraviolet and infrared cut filter is interposed between the objective lens and the CCD. The cut coating and the cut filter have a total transmittance of 0.1% or lower for ultraviolet light.

Abstract: An electronic endoscope of the present invention includes a video-scope, video-processor, a light source, a luminance value calculator, a light-adjuster, and a determiner. The luminance value calculator successively calculates a luminance value indicating brightness of the object image, on the basis of said image-pixel signals. The light-adjuster adjusts a quantity of light radiating from the distal end of the video-scope on the basis of a difference between the luminance value and a reference value indicating a proper brightness of the object image at regular-time-intervals, such that the brightness of said object image displayed on the monitor is maintained at a constant level. The determiner determines whether halation occurs on the object image displayed on the monitor, on the basis of the luminance value. The light-adjuster includes a light-reducer.

Abstract: A fluorescent endoscope apparatus in which the fluorescent light, which becomes noise, emitted from the photographic element propagating the autofluorescent light emitted from a living-tissue subject is reduced, and by which it is possible to clearly distinguish between normal and diseased tissues. The fluorescent endoscope apparatus has a stimulating light projecting unit for irradiating a living-tissue subject with stimulating light, and an optical element for propagating the autofluorescent light emitted from the living tissue subject that has been irradiated by stimulating light. It also has a photographing element, which is formed of the optical element, for photographing the autofluorescent light emitted by the living tissue subject irradiated by the stimulating light. The optical element is structured so as to satisfy the condition expressed by the formula: the strength of the autofluorescent light of normal tissue≧the strength of the autofluorescent light of the optical element×104.

Abstract: Endoscopes and other viewing devices that control the light that contacts a sample and/or that is detected emanating from a sample. The viewing devices are particularly well suited for in vivo imaging, although other uses are also included. The viewing devices, and methods related thereto, comprise a spatial light modulator in the illumination and/or detection light path so that light transmitted to the target via a bundle of light guides or optical system is transmitted substantially only into the cores of the light guide bundle and not into the cladding surrounding the light guides, filler between the light guides in the bundle, or undesired light guides. Also, methods and apparatus for mapping the pixels of the spatial light modulator to the cores of the light guides in the bundle (preferably at least 3 pixels (e.g., at least 3 mirrors for a digital micromirror device) for each core), as well as for mapping the light guides of one light guide bundle to another.

Abstract: A device for positioning at least one optical component within an endoscopic system has a housing, through which runs an optical axis, and in which at least one component is arranged. The component is pivotable into the beam path of the endoscopic system about a pivot axis and pivotable out of the beam path. The pivot axis is here arranged running obliquely to the optical axis.

Abstract: White light emitted from a first light source is sequentially converted into green light, blue light, and red light by a first wheel. Excitation light emitted from a second light source passes through a second wheel. The green light, the blue light and the red light, and the excitation light are switched by shutters to enter a prism. The optical path of the green light, the blue light and the red light transmitted through the prism coincides with the optical path of the excitation light reflected by the prism. As a result, the green light, the blue light, the red light and the excitation light sequentially and repeatedly enter a light guide.

Abstract: A light source device comprises an aperture mechanism having a pair of aperture blades in an optical path formed between a light source and an incident end surface of a light guide on which an illuminating light is made incident. The first and second aperture blades are rotated, in a plane perpendicular to the optical axis of the optical path, about a movable shaft, which is parallel to the optical axis. The first and second aperture blades shade the luminous flux of the illuminating light, to adjust the amount of illuminating light, from the outer peripheries of the section of the luminous flux. A protruding plate is formed on an inside periphery of the first aperture blade. When the first aperture blade closes a half of the section, the protruding plate shades a swinging region above the center of the section of the luminous flux.

Abstract: An endoscope is disclosed that includes a light source unit for illuminating an object, and an optical system which forms images of the object and includes a spectral filter. The spectral filter includes a first region which has a first spectral transmission and a second region which is peripheral to the first region and which has a second spectral transmission that is different from the first spectral transmission, to thereby enable endoscope images of the object to be obtained wherein fine details as carried by high spatial frequencies in the image light of certain wavelengths are emphasized for those wavelengths that are passed by the second region of the spectral filter. In addition, the endoscope may contain a phase mask and an image processing means which serve to extend the depth of field in the wavelength range passed by the second region of the spectral filter.

Abstract: There is provided a light shielding plate to shield light from a light source lamp, and this light shielding plate is rotated and driven by a light shielding plate drive circuit, and a charge stored in a CCD for a period of, for example, 20H at a start of an effective period J of a vertical scanning period, is discharged and this is set as a non-operating period and a drive control over the light shielding plate for a period of 40.5H which is a sum of this non-operating period and a blanking period B (20.5H) is performed. This provides an adequate margin of time for controlling the light shielding plate at starting and stopping times and makes the drive control easier.

Abstract: An endoscope according to the invention includes a red component cut optical filter having a characteristic that a spectral transmittance becomes half at 630 nm and zero at 670 nm, for example between a light source and an infrared cut filter, to remove a long wavelength component mainly in a red band of illumination light. This restrains scattering of light on a long wavelength side of red light, and allows taking images of mucosa, blood vessels, and other tissue in good contrast in an object to be observed and satisfactorily observing them on a monitor. Further, reduction in light amount resulting from cutting a red component with the filter is eliminated by light amount control with an aperture and gain control of a signal.

Abstract: A light source device for endoscopes capable of preventing an incident end-face of a lightguide from generating heat due to infrared light emitted from a light source, and capable of radiating sufficient ultraviolet light and visible light. A light source emits at least ultraviolet light, visible light and infrared light. A condenser lens condenses the light emitted from the light source at the incident end-face of a light guide. A wavelength control filter and another selected filter are arranged between the light source and the condenser lens. Each optical axis of the light source, the wavelength control filter, the selected filter, the condenser lens, and the lightguide is linearly aligned, thereby providing a simplified alignment operation in manufacturing processes.

Abstract: A monocular borescope or endoscope is provided with an image relaying means (16) defining a longitudinal axis (L)(and with a viewing means comprising an ocular lens (20) and field mask (18) defining a central axis (C) which is parallel to and offset from the longitudinal axis (L). In one embodiment the ocular lens (20) is coincident with the central axis (C) of the mask (18), while in another embodiment the ocular lens (20) is coincident with the longitudinal axis (L). The mask (18) is arranged to be mountable in a number of different rotational orientations each providing a different offset between the longitudinal axis (L) and the central axis (C).

Abstract: An video endoscope system has, as main components, a video endoscope equipped with a light guide, a light source device for supplying illumination light and exciting light to the light guide, and an endoscope processor to process image signals and to control the light source device. The light source device is composed of a white light source for generating a collimated beam of white light, an ultraviolet light source for generating a collimated light beam having wavelengths in the ultraviolet region, and a UV reflection filter for transmitting white light while reflecting ultraviolet light, as main components. In the optical system for the light source device, the UV reflection filter is arranged at an angle of 45 degrees to both the collimated beam of white light and the collimated light beam having wavelengths in the ultraviolet region that intersect each other orthogonally.

Abstract: Light emitted from a light source is converted into ultraviolet-and-blue light, green light, and red light, in that order, by a first wheel. When a second wheel inserts a transparent member 251 into the optical path, the ultraviolet-and-blue light, the green light, and the red light enter a light guide. On the other hand, when the second wheel inserts a fluorescence observation filter into the optical path, ultraviolet-and-blue light is converted to ultraviolet light and then enters the light guide, while the green light is blocked and the red light enters the light guide.

Abstract: A larger number of micromirrors arranged on an illumination optical path of a lamp in a light source device for supplying an illumination light to an endoscope and by using a silicon chip as a base are arranged the micromirrors in a two-dimensional are set at two angles. When the micromirrors are set at one of the two angles, a reflected light is supplied to the light guide. When the micromirrors are set at the other angle, the micromirrors are driven such that the reflected light is not supplied to the light guide. An intensity of illumination light supplied to the light guide or the like is adjusted at a high speed by using a brightness level by selected the micromirrors at the two angles respectively, so that an endoscope image which can be easily observed is obtained.

Abstract: The present invention is a unit for eliminating the fluctuation of luminous energy reduction by keeping the response time of a shading mechanism constant even if a diaphragm opening degree differs when reading every pixel by setting a shading period. This unit is provided with a shading mask having a quadrangular or V-shaped opening and moves a shading shutter in the horizontal direction perpendicular to the vertically moving direction of a diaphragm plate. Therefore, a shading period is set in accordance with the constant response time of the shading shutter and the rate of luminous energy reduction becomes constant. Moreover, a high-quality static image having a stable brightness can be obtained by reading the signal of every pixel obtained by a CCD through one-time exposure while using the shading period and then pixel-mixing signals. Furthermore, it is possible to use the Archimedean spiral for the outer periphery of the diaphragm plate or the shading shutter.

Abstract: The present invention is a unit for eliminating the fluctuation of luminous energy reduction by keeping the response time of a shading mechanism constant even if a diaphragm opening degree differs when reading every pixel by setting a shading period. This unit is provided with a shading mask having a quadrangular or V-shaped opening and moves a shading shutter in the horizontal direction perpendicular to the vertically moving direction of a diaphragm plate. Therefore, a shading period is set in accordance with the constant response time of the shading shutter and the rate of luminous energy reduction becomes constant. Moreover, a high-quality static image having a stable brightness can be obtained by reading the signal of every pixel obtained by a CCD through one-time exposure while using the shading period and then pixel-mixing signals. Furthermore, it is possible to use the Archimedean spiral for the outer periphery of the diaphragm plate or the shading shutter.

Abstract: An objective lens is substantially telecentric toward the image side, and provided with an ultraviolet cut coating on its rearmost surface. An imaging plane of a CCD is arranged near a position where an image of an object is formed through the objective lens. An ultraviolet and infrared cut filter is interposed between the objective lens and the CCD. The cut coating and the cut filter have a total transmittance of 0.1% or lower for ultraviolet light.

Abstract: A device for positioning at least one optical component within an endoscopic system has a housing, through which runs an optical axis, and in which at least one component is arranged. The component is pivotable into the beam path of the endoscopic system about a pivot axis and pivotable out of the beam path. The pivot axis is here arranged running obliquely to the optical axis.

Abstract: Viewing apparatus, for medical and surgical practitioners incorporating one or more optical filters, each exhibiting a reverse photopic response, such that green light is at least partially attenuated, whereas red and blue light are both substantially transmitted. The invention includes means for supporting one or more optical filters in the practitioner's field of view, such as a pair of eyeglass frames or endoscope mounting for use, for example, in conjunction with laparoscopic surgery. Various technologies may be employed to realize a desired reverse photopic response, including absorptive dyes, dielectric layers, and/or holograms.

Abstract: An endofluorescence module is utilized with an interventional device insertible in a body to provide at least one fluorescence excitation source. The module can be attached to the distal end of an endoscope, cystoscope or other optical imaging device. One or more filters are utilized to enhance the fluorescence response from the tissue under examination. A light shutter controls the exposure of an optical channel during operation. The adaptability and small size of the module correspond with low cost and disposability.

Abstract: The present invention is a unit for eliminating the fluctuation of luminous energy reduction by keeping the response time of a shading mechanism constant even if a diaphragm opening degree differs when reading every pixel by setting a shading period. This unit is provided with a shading mask having a quadrangular or V-shaped opening and moves a shading shutter in the horizontal direction perpendicular to the vertically moving direction of a diaphragm plate. Therefore, a shading period is set in accordance with the constant response time of the shading shutter and the rate of luminous energy reduction becomes constant. Moreover, a high-quality static image having a stable brightness can be obtained by reading the signal of every pixel obtained by a CCD through one-time exposure while using the shading period and then pixel-mixing signals. Furthermore, it is possible to use the Archimedean spiral for the outer periphery of the diaphragm plate or the shading shutter.

Abstract: In an electronic endoscope, a video-scope has an image sensor for photographing an object image and a light guide for guiding light toward an object. A video-processor has a light source, a stop, a signal conversion circuit, a histogram processing circuit, and a CPU. When the video-scope is connected to the video-processor, light emitted from the light source is guided by the light guide and radiates from a distal end of the light guide, so that an object image is formed on the image sensor. The object image is then converted into the image-pixel signals. Further, a representative value, which relates to a brightness of the object image, is calculated on the basis of the image-pixel signals through the signal conversion circuit, the histogram processing circuit, and the CPU. Then, a control of light radiating from the distal end of the light guide is performed at regular time-intervals. Namely, the stop is controlled such that the brightness of the object image is proper.

Abstract: The present invention is an electronic endoscope apparatus that can appropriately compensate for the lack of light quantity caused by a delayed response from a shielding mechanism in using the all-pixel reading system to form a high-quality image. In this apparatus, for a moving image, a pixel mix signal is read out from a CCD to reproduce motions faithfully. For a still image, to improve the image quality, a shielding period set by the shielding plate is used to read out all the pixels obtained by the CCD during a single exposure in order to form a pixel mix signal using a mixing circuit. A lamp characteristic memory stores table data indicating the characteristic between the lamp voltage of the current lamp and the quantity of outgoing light so that based on this data, a lamp voltage higher than in moving images is supplied to the lamp during the exposure for still-image formation.

Abstract: The endoscopic light source apparatus has an illuminating light converging mechanism (20) in which a lightguide connector (3) to be connected displaces a condenser lens (22) in a direction parallel to the optical axis of illuminating light so that irrespective of the length of the lightguide connector (3), the illuminating light entrance end face (4a) of the lightguide connector (3) is located near the position in which the rays of illuminating light converge, and a filter inserting and retracting mechanism (30) which moves in operative association with the illuminating light converging mechanism (20) such that a light attenuating filter (31) is inserted into or retracted from the rays of illuminating light depending upon the length of the lightguide connector (3).

Abstract: An objective lens system for endoscopes comprising a first lens component (L.sub.1) which has no or a negative refractive power, a second lens component (L.sub.2) which has a convex image side surface and a third lens component (L.sub.3) which has a convex object side surface, wherein a radius of curvature r.sub.3F on the object side surface of the third lens component and a thickness of the third lens component satisfy the following condition:3<r.sub.3F /D.sub.3 <10.

Abstract: Apparatus and methods that permit the direct viewing of induced tissue fluorescence or other response by a human viewer through an endoscope without the need for bulky and expensive auxiliary apparatus such as imaging devices, sensor arrays, analyzing systems and computer hardware and software. The apparatus and methods provide an excitation energy, such as blue light, that is transmitted to the target, and then the endoscope collects the emitted response, which is typically fluorescent light of a wavelength longer than the UV or blue light used to induce the fluorescence. The endoscope then transmits the response through a series of filters in the endoscope and directly to the eye of a human user.

Abstract: A light source device for endoscopes includes a light source for emitting white light containing the components of light belonging to a visible region and wavelength bands other than the visible region; at least, a rotary color separating filter on a field sequential system; and an infrared cutoff filter for blocking light in an infrared region, of a wavelength band of the white light. When the rotary color separating filter is disposed in an optical path from the light source to a light guide, an interference filter in which an interference film is applied to a transparent base plate is placed in the optical path. This arrangement obviates the defect of burning the entrance end of the light guide or of breaking the infrared cutoff filter.

Abstract: In an electronic endoscope system for detecting an image of an object using a CCD, a brightness signal is generated based on the output of the CCD, and a histogram processing is applied to the brightness signal. An aperture size for regulating the amount of light emitted to an object to be viewed is controlled in accordance with the calculation based on the histogram data.

Abstract: A heat attenuating spacer device interconnects an endoscope to a first end of a fiberoptic conductor. The opposite end of the conductor is operably engaged with a fiberoptic light source. The endoscope has an entry port for introducing light into the endoscope, which entry port is communicably engaged with the first end of the conductor. The spacer device includes a spacer body and an inlet formed in the spacer body. The inlet is communicably engaged with the first end of the conductor to receive light therefrom. An outlet is formed in the body and spaced apart from the inlet. The outlet is communicably engaged with the entry port of the endoscope. The body transmits light from the inlet to the outlet, which light is discharged from the outlet and introduced into the endoscope through the entry port. The spacer body and/or a filter contained by the body thermally insulates the light conductor from the endoscope.

Abstract: An endoscope system including a first hard endoscope which uses a relay lens as an image transmission optical system, a second hard endoscope which uses an image guide formed by a fiber bundle, and a TV camera which is mountable respectively on the first and second hard endoscopes and which is rotatable. The TV camera has built therein a CCD. An optical low-pass filter for removing moire even in case of being rotated is provided on an ocular part of the second hard endoscope.

Abstract: An endofluorescence module is utilized with an interventional device insertible in a body to provide at least one fluorescence excitation source. The module can be attached to the distal end of an endoscope, cystoscope or other optical imaging device. One or more filters are utilized to enhance the fluorescence response from the tissue under examination. A light shutter controls the exposure of an optical channel during operation. The adaptability and small size of the module correspond with low cost and disposability.

Abstract: A light adjustable endoscope is disclosed for use in combination with a standard fiberoptic illuminator having a light output port. The endoscope includes a scope portion and an apparatus interconnected between the illuminator and the scope for transmitting light to the scope and adjusting the intensity and/or color of that light.

Abstract: The invention relates to a device for the photodynamic endoscopic diagnosis of human or animal tumor tissue with the help of a marker substance capable of fluorescence and with an endoscope and a light source. With this, means are provided in order to guide light from the light source via an endoscope to the diagnosis location in each case in one of at least two selectable spectral regions, that is in a white light region and in a region with blue-violet light, in order thus in each case to be able to carry out a visual examination with white light and stimulate a marker substance deposited in any tumor tissue to fluoresce. The means for selecting the light comprises an anti-fading filter which can be pivoted into the beam path of the white stimulation light on examination with white light and which filters out light, lying in spectral region stimulating fluorescence, from the white light.

Abstract: An endoscope system includes an imaging unit for converting an image of an object into an image signal, and an automatic amount-of-light setting circuit for setting an amount of light output from a light source apparatus on the basis of the image signal provided by the imaging unit. According to a setting signal sent from the automatic amount-of-light setting circuit, the amount of light output from the light source apparatus is adjusted. Aside from the automatic amount-of-light setting circuit, a device used to set an amount of light manually is included. The automatic amount-of-light setting circuit and manual amount-of-light setting device can be switched selectively by means of a switch. Consequently, a drawback of the automatic amount-of-light setting circuit occurring when the endoscope is removed from a human body, that is, the drawback that when control is given for lowering the level of the image signal, the amount of light is increased will not take place.

Abstract: An endoscope optical system is used in an endoscope which can be combined with at least two laser treatment units that produce different wavelengths. At least two filters for removing laser light are provided in the path of the optical system, and are arranged at positions where angles of incidence or emergence of a chief ray are different. In this way, even with the laser treatment units using a plurality of wavelengths, laser light of the plurality of wavelengths can be removed.

Abstract: A distal end part of an endoscope having a viewing window for introducing light from an object into an objective optical system for forming an observed image. An illuminating window is disposed in a side by a side relationship with the viewing window for illuminating a visual field of the objective optical system. A continuous transparent cover covers the surfaces of both the illuminating and viewing windows. A window glass is attached to the viewing window in such a manner that a virtual image of the outer edge portion of the window glass, which is produced by single reflection from the inner side of the outer surface of the transparent cover, lies outside the visual filed of the objective optical system.

Abstract: An exciting light filter through which exciting light which is adapted to radiate fluorescence from a living tissue is transmitted, is provided in an illumination light path defined between a light source which emits the illumination light and an object to be observed, in a fluorescence endoscope. A fluorescence filter which permits fluorescence which is radiated from the living tissue due to the illumination by the exciting light and whose wavelength is longer than that of the exciting light to pass therethrough but does not permit the exciting light to pass through the fluorescence filter, is provided in an observation light path defined between the object and a viewing portion in which an image of the object is viewed. There is a difference of 20 nm to 40 nm between the longest wavelength of the wavelength band of which more than 10% are transmitted through the exciting light filter and the shortest wavelength of the wavelength band of which more than 10% are transmitted through the fluorescence filter.

Abstract: An imaging apparatus for endoscopes includes an endoscope relaying an object image through an observing optical system, and an imaging section removably mounted to the rearmost end of the endoscope, including a stop unit provided with a variable stop capable of changing an aperture size thereof, an imaging lens system, a focus lens system, and an image sensor. The relative positions of the variable stop, the imaging lens system, and the image sensor are constant, and the focus lens system can be moved along the optical axis of the imaging section. In this way, the imaging apparatus for endoscopes can be provided which is simple in structure, small in size, and low in cost.

Abstract: A light source device for endoscopes includes a light source for emitting white light containing the components of light belonging to a visible region and wavelength bands other than the visible region; at least, a rotary color separating filter on a field sequential system; and an infrared cutoff filter for blocking light in an infrared region, of a wavelength band of the white light. When the rotary color separating filter is disposed in an optical path from the light source to a light guide, an interference filter in which an interference film is applied to a transparent base plate is placed in the optical path. This arrangement obviates the defect of burning the entrance end of the light guide or of breaking the infrared cutoff filter.