KR20140118449A - Endoscope apparatus - Google Patents

Abstract

The present invention relates to an endoscope assembly which has a housing which is suitable for a health professional such as a surgeon to operate. A long stage is fixated to be removable from the housing so that the stage surrounds a tube and is coaxial with the tube while a lens tube has an end which is fixated on the housing. The stage is suitable for being inserted into the cavity of a body with the lens tube. A lens assembly provided in the lens tube relays an image from the free end of the stage to the housing. The lens assembly in the housing also changes the magnification of an image between a macro-magnification and a micro-magnification capable of examining a tissue at a cell level. In the macro-magnification, white light is transmitted not only through the lens tube but also to the housing by being reflected from a target tissue through the lens tube. In the micro-examination, a laser beam is used instead of white light illumination. A line scanning confocal assembly built in the housing is able to examine a target tissue at a micro-magnification from the end of the stage into a tissue at various levels.

Description

ENDOSCOPE APPARATUS [0001]

The present invention relates to an endoscope apparatus.

The conventional endoscope has various drawbacks. Perhaps the most important disadvantage of the conventional endoscope is that the magnification range of the endoscope is constant since the lens is fixed in the endoscope. In general, a conventional endoscope uses a lens that can perform a low magnification or a large magnification (hereinafter referred to as a large magnification) in the body cavity to obtain a relatively wide observation range of the body cavity.

However, in many cases, an endoscope of a small magnification organs contained in the body cavity may be preferable. For example, when it is suspected that cancer is growing in the body organs, a large magnification by a conventional endoscope is sufficient to judge whether or not a tissue abnormality has occurred in the cancer or a symptom of cancer It is insufficient for detailed inspection. Thus, the surgeon was required to remove the tissue for biopsy and, in many cases, to remove the entire organ from the body for subsequent pathology.

There are two major disadvantages to removing biotissue from the body and performing subsequent pathologic testing outside the body.

The present invention provides an endoscope for use in laparoscopic surgery that overcomes the above-mentioned disadvantages of the conventional device.

The endoscope of the present invention has a lens assembly that forms a light path in an endoscope tube wherein the light path is shared by both the lens used to illuminate an object such as tissue within the body cavity and the light collected from the object . The endoscope tube is coupled to an outer housing having an additional lens assembly and the combined endoscope tube and housing lens forms an image on one or more detectors in a housing that converts the image into an electronic signal. A cable is provided for the electronic and optical interface between the housing and the external control system, such as a personal computer, a power supply, and a light source.

The magnification achieved by the endoscope assembly may vary between large, or low, magnification and micro, or high magnification. Giant magnification is used to provide a surgeon with an optical view of a relatively large area within the body cavity, while in micro-magnification mode the system can analyze the structure of the cellular level. In the micro-mode, the system provides high-resolution imaging of the epidermal layer of the body tissue as well as the layer below the epidermal layer by the confocal assembly contained within the housing.

By using near infrared rays of wavelengths that are generally more transparent than the wavelengths that can see the body tissue grossly, thorough imaging is improved.

The lens assemblies in the housing include separate or partially discrete paths to the macro and microimaging modes. A beam splitter is provided to separate the combined optical path of the endoscopic lens into separate paths of the housing lens, and optionally recombine the path onto one CCD camera. It is preferable to use a 3-chip CCD camera detector to use white light for the giant magnification path and to provide imaging of the entire color. The light source used in the micro-magnification mode is preferably a laser diode that operates at a wavelength of about 950 nm in the near-infrared region of the spectrum. The microscopic magnification path of the housing includes a confocal assembly that provides a high resolution shape of both the surface of the tissue and the thin, deep portion within the tissue. Confocal assemblies include scanning means which desirably operate in a line-scanning format, although other scanning techniques such as point scanning or nipkow disc scanning may be used.

The endoscope apparatus according to the present invention can electronically switch between the white light visualization method and the fluorescence visualization method in this way without requiring a moving part in the endoscope itself. By removing the camera and imaging optics at the base end of the endoscope, its handling characteristics are significantly improved. A computer based imaging system allows quantitative imaging of the tissue to be displayed at a reproduction rate of, for example, 10 Hz or more. The preferred embodiment uses an easily viewable false color overlay to indicate areas of high likelihood of dysplasia. The term "stomach color" means that color intensities are assigned to the fluorescence intensity of a particular level of each pixel. The data processing system may be programmed to provide a colorimetric suitable for a given type of tissue condition. Such a system may be used with a color wheel (e.g., using a monochrome CCD) or with a color imaging sensor endoscope.

1 is a diagram illustrating an embodiment of the present invention.
2 is a diagram illustrating a lens tube of the embodiment of the present invention and a lens assembly incorporated therein.
3 is a view illustrating an exemplary lens assembly for an objective lens according to an embodiment of the present invention.
4 is a view of a relay lens assembly of an embodiment of the present invention.

A preferred embodiment of an endoscope assembly 200 of the present invention is shown. The endoscope 200 includes an elongated endoscope lens tube 202 having an opposite end attached to the free end 204 and the housing 206. The housing may also be attached to a machine support or a robotic arm, but is designed to be hand operated by a surgeon or healthcare worker. The elongated tubular stage 208 is slidably received past the free end 204 of the lens tube 202 and is removably attached to the housing 206 by a mechanical coupling 207 such as a veneer net coupling Lt; / RTI > The stage 208 has a transparent window 210 that is located beyond the free end 204 of the lens tube 202. The lens tube 202 with the stage 208 is inserted into the patient through the cannula while the housing 206 remains outside the patient.

2 to 4, a plurality of optical lenses are disposed in the lens tube 202 so as to extend along the length of the lens tube 202. These lenses include an objective lens 212, which is clearly shown in Fig. 3, extending from the free end 204 of the lens tube 202 to the inside of the lens tube 202. A window 215 is attached to the free end 204 of the lens tube to provide an optical interface into the space beyond the objective lens. One or more conventional relay lenses 214 are embedded within the lens tube at regular intervals from the objective lens 212 to the housing 206. The objective lens 212 together with the relay lens or lenses 214 provides an image of the optical view at the free end 204 of the lens tube 202 to the housing 206.

Next is a view of the free end of the endoscope 200 where the window 210 on the stage 208 is positioned against the tissue 216 being examined. The lens tube 202 can move axially relative to the stage 208 from the retracted position shown in Figure 5A to the extended position shown in Figure 5B. As the lens tube moves from the retracted position to the extended position, the objective lens 220 moves from the surface of the tissue 216 to a known depth in tissue. Any conventional means 219 (see Figure 1), such as a stepper motor or a manual knob, may be used to move the lens tube relative to the stage.

The stage 208 has a cylindrical collar 209 attached to the housing 206 in close proximity. The collar 209 forms a mounting structure through which the stage can be attached to a machine support, such as a robotic arm. A chamber 222 between the window 215 at the free end 204 of the lens tube 202 and the window 210 on the stage 208 is provided with a liquid whose refractive index is approximately equal to the refractive index of the tissue to be examined, It is filled with saline solution. When the lens tube retracts or elongates, the liquid is either withdrawn from the reservoir or returned to the reservoir, thereby maintaining a constant light depth to the object to be observed and minimizing the optical aberration. The reservoir can be a separate bladder or simply the space between the lens tube 202 and the stage 208 as illustrated in FIG. 5B.

It is appropriately filtered at either the lamp or the housing to be removed. An optical fiber cable 258 transmits light from the lamp to the housing. The lens 262 forms an image of the optical fiber surface 260 in the pupil plane of the macropathic path of the housing lens assembly. The illumination light passing through the lens 262 and the plane polarizer 264 is reflected by the beam splitter 248 and focused by the lens 246. [ The illumination further passes through beam splitter 244, collimating lens 242, and field lens 240, then through lens 202 to illuminate the object to be observed.

Light returned from the object to be observed passes through the lens tube 202 and returns to the housing lens assembly where it passes through the field lens 240 and is collimated by the lens 242. The light having the phase continues to pass through the beam splitter 244 and the focusing lens 246. The light passes through a beam splitter 248 and a planar polarizer 250 and then is focused on the focal plane of the video camera 254 by a camera lens 252. The video camera 254 may be used with other detectors such as a CMOS detector, but it is preferable to use a CCD detector.

The focusing lens 246, as schematically shown as one lens member, may alternatively be one or more lens assemblies including a plurality of lens members. By moving the focussing lens 246 in the axial direction by moving means 266 to compensate for different object working distances of the endoscope, focus can be maintained on the video camera focal plane when the endoscope distance from the object changes. The lens can be moved by manual means, a manually controlled motor, or a computer controlled motor. Focusing lens 246 uses an autofocus device and appropriate servo motor to maintain the image at the proper focus. In addition, such circuitry is known in the art so as not to require further explanation.

The above described method of sharing the lens tube light path by both illumination and phase-support light minimizes the desired diameter of the endoscope lens tube 202, since it does not require a separate illumination path, The contact object can be illuminated. The stray light due to undesired reflection from the lens surface can be minimized by controlling the polarization state of the illumination and phase-support light described below.

The two polarizers 250 and 264 in the macropath path minimize the amount of stray light that does not have an image reaching the focusing surface of the video camera 254. [ The illumination light is linearly polarized by the planar polarizer 264, and the phase-supporting light passes through the planar polarizer 250. The polarizer 264 is oriented at right angles to the polarizer 250, so that the specular reflection from the lens surface in the endoscope and the housing does not reach the focusing surface of the video camera 254 reliably. Since the light scattered by the objective lens is not polarized, half of the light is transmitted to the camera 254 by the polarizer 250. In addition to or as an alternative to the polarizers 250 and 264, the beam splitter 248 may be a polarization beam splitter that transmits one polarization and reflects orthogonal polarization.

Preferred lasers that are located within the housing provide illumination for micro-mode, i.e., imaging at the cellular level. Although lasers can be used at different wavelengths, laser diodes that operate at a wavelength of about 950 nm are preferred so that contrast and tissue penetration are optimal.

The micro-mode includes a confocal lens assembly in its path for high resolution in the depth and high resolution in the cross direction. In a preferred embodiment, the confocal assembly uses line scanning, but other known methods such as point scanning or nipkow disk scanning may be used.

Subsequently, the light from the laser diode 290 is focused on the line by the cylindrical lens 292. The first slit 294 may be placed in line focus to clean the beam as a spatial filter or provide an alignment reference during fabrication.

After passing through the slit 294, the illumination passes through the plane polarizer 296 and the beam splitter 278. The laser light is then collimated by the focusing lens 276 and reflected from the first surface of the scan mirror 272. After being reflected, the illumination light passes through the adaptive lens 270 and is reflected by the beam splitter 244. The beam splitter 244 is preferably provided with a dichroic coating that reflects near-infrared light and transmits visible light. The collimating lens 242 and the field lens 240 direct the illumination light into the lens tube 202 and the lens in the tube converges the laser light to the line of the object to be inspected and the line is the image of the slit 294. Further, as shown in FIG. 3, the illumination light passes through the optical retarder 218 located in the objective lens 212.

210 ... Stage window
240 ... field lens
250 ... Polarizer

Claims (4)

housing,
An elongated lens tube secured at one end to the housing and suitable for insertion into a cavity of the body,
A tube lens assembly built into the lens tube and optically relaying an image from the free end of the lens tube to the housing,
A housing lens assembly for receiving an image from the lens tube,
Camera means for receiving the image from the housing lens assembly and converting the image into an electronic signal;
And means for changing the housing lens assembly between a small magnification and a large magnification.
The method according to claim 1,
A visible light emitting source coupled to the housing,
An infrared light emitting source coupled to the housing, and
And means for selectively directing light emitted from one of the light emitting sources coupled to the housing through the lens tube assembly.
3. The method of claim 2,
Wherein the selective directing means comprises a first shutter optically connected in series with the visible light emitting source and a second shutter optically connected in series with the infrared light emitting source.
The method according to claim 1,
Wherein the housing lens assembly comprises a confocal lens assembly.

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