Tip chip endoscope with improved 3D vision

Abstract

The invention relates to a tip chip endoscope with improved 3D vision. In order to improve the image quality of stereoscopically observed images recorded with a CIT endoscope (1), it is proposed that an optical correction element (11) is arranged between two optical channels (4a, 4b) for imaging and an image sensor (2) for imaging, said optical channels extending in parallel and having the same design, the optical correction element moves the respective main rays (20a, 20b) of the respective optical channels axially parallel in such a way that the imaging ray paths (5a, 5b) generated by the two optical channels approach each other. As a result, the image center distance D between the image regions (6a, 6b) of the image sensor (2) on the sensor surface (7) for the two individual images can be reduced in such a way as to be compared to a stereoscopic base line B on the incidence side defined by the two optical channels, such that a higher image resolution can be achieved.

Description

Technical Field

[0001] This invention relates to a chip-in-tip (CIT) endoscope for stereoscopic observation, the CIT endoscope having a distal image sensor disposed in the distal tip section of the endoscope, and further having two optical channels (particularly by means of optical lenses and, if necessary, other optical elements) forming an imaging ray path. Each imaging ray path here produces a corresponding image region for imaging: the left channel illuminates a left image region on the sensor surface of the image sensor, and the right channel illuminates a corresponding right image region on the sensor surface of the image sensor. Within these image regions on the sensor surface, a disk-shaped or rectangular area of ​​pixels can be read to obtain a corresponding single image (of the left or right channel). Here, the corresponding geometric image center points of the two image regions define the image center distance D (on the sensor surface). Furthermore, each of the two imaging ray paths defines a corresponding optical axis that extends through the corresponding optical channel. The two optical axes are here set at a distance B on the incident side, the distance defining the stereoscopic baseline of the endoscope. Therefore, this endoscope is designed for stereoscopic observation or for recording stereoscopic images, thus enabling 3D imaging or 3D visualization. Background Technology

[0002] Such CIT endoscopes have long been known in the prior art and have been utilized, in particular, to provide surgeons with a fluoroscopic view, and therefore a spatial impression, of the surgical area during surgical interventions within the body. This significantly facilitates manipulation, or more precisely, manual control of surgical instruments. The spatial impression generated in the user's mind depends here on the size of the aforementioned stereo baseline. This stereo baseline is the distance between the two optical axes through which the endoscope views the object to be observed, or in other words, the endoscope obtains imaging rays from the object through these two optical axes. Summary of the Invention

[0003] The objective of this invention is to enable improved 3D imaging using a CIT endoscope. In particular, the quality of stereoscopic images recorded using the endoscope should be improved.

[0004] To solve this task, the features of claim 1 are incorporated into the endoscope according to the invention. Specifically, the invention proposes, therefore, a CIT endoscope of the type described at the beginning to solve the aforementioned task, wherein the endoscope has an optical correction element (with respect to the corresponding imaging ray path) disposed between the two optical channels and the at least one image sensor. The optical correction element is designed such that at least one of the two optical axes (predetermined by the corresponding optical channels) mentioned earlier, however preferably both optical axes, preferably parallel, is moved in such a way that it is suitable for D... <B。

[0005] That is, the image center distance D is less than the stereo baseline.

[0006] Depending on the image sensor used, especially when the image sensor does not have a high requirement for the so-called principal ray angle (CRA), non-axis-parallel movement is also possible. In this case, the corresponding optical axis can also be incident on the image sensor surface at a (slightly) tilted angle. However, axis-parallel movement is preferred because it is particularly possible to achieve, after the corresponding optical axis is moved in the correction element, to be incident perpendicularly on the sensor surface of the image sensor. This allows for "matching" / consistency of the CRA between the imaging optics and the image sensor, which is advantageous in order to avoid shading and color errors. Lateral chromatic aberration when passing through the correction element can also be better limited with axis-parallel movement.

[0007] In other words, the optical correction element thus reduces the distance between the two optical axes. This specifically allows the two image regions to be brought closer together on the active sensor surface of the image sensor. This has the technical effect that the active sensor surface of the image sensor can be better used for imaging in the sense that more pixels are available for the corresponding single image. This improves the image resolution of each of the two single images used for sensorial detection within the corresponding image regions, and thus results in an overall improved resolution stereoscopic image.

[0008] As will be more clearly seen with the aid of examples, the optical correction element in the sense of the present invention may consist of a plurality of optical components.

[0009] The two optical channels therefore have a left optical channel and a right optical channel. Here, the left optical channel produces the left imaging ray path that defines the left image region, and the right optical channel produces the right imaging ray path that defines the right image region.

[0010] The (activated) sensor surface of the image sensor is typically larger than the sum of the areas of the two image regions actually used for imaging. This is especially true in cases where, for example, a circular image region is used (as is often the case in stereoscopic endoscopes used for minimally invasive surgery) or a narrow, unused area of ​​the sensor surface is reserved between the left and right image regions used for imaging (which is advantageous for a number of reasons).

[0011] Using such an optical correction element can, in particular, cause the corresponding optical axes to deviate. Preferably, the two optical axes here can be moved parallel to each other and thus brought closer together by the optical correction element (which may consist of multiple components). In other words, the two optical axes can therefore have a greater distance when entering the optical correction element than when they exit from the same optical correction element.

[0012] The optical correction element can thus offset at least one of the two optical axes in such a way that the image center distance D is reduced compared to the case where no such offset element is used in the endoscope. Here, the optical correction element can offset at least one of the two optical axes, and preferably both optical axes, in particular, such that the two image center points are further brought closer to each other.

[0013] In a typical stereoscopic endoscope, the corresponding optical axis does not undergo such an offset along the corresponding left optical channel, thus altering the distance between said optical axis and the optical axis of the adjacent right channel. Therefore, in these prior known stereoscopic and endoscopic imaging systems, the distance between the image center points of two single images corresponds to the stereo baseline on the incident side, defined by the distance through the first lens of the imaging optics on the incident side of the two optical channels. A larger stereo baseline results in a greater spatial impression for the observer when viewing a stereoscopic image, which is typically advantageous for achieving good 3D perception. However, with a large stereo baseline, the valuable sensor surface of the image sensor is often not used for imaging in prior known systems, which disadvantageously affects the achievable image resolution.

[0014] The distance between the image-side and incident-side defined stereo baseline B of the two optical axes at the distal ends of the two optical channels thus defines the spatial impression of stereoscopic imaging achievable using the endoscope. According to the invention, the image center distance D is configured to deviate from the stereo baseline B based on the optical offset caused by the optical correction element, and is particularly smaller than the stereo baseline B.

[0015] If only a limited wavelength spectrum is used for imaging, it is technically possible to design the optical correction element using diffractive optical elements that cause the desired ray deflection.

[0016] Alternatively, it is also possible to (at least in part) use reflective optical elements, such as tilted planar mirrors, to design the optical correction element according to the invention.

[0017] According to the invention, the task can also be solved by other advantageous embodiments as further explained in the dependent claims.

[0018] Advantageously, for example, the corresponding overall imaging optics of the corresponding optical channel is positioned before the optical correction element along the direction of the corresponding imaging ray path. This is because image errors can be avoided compared to placing the optical correction element within the corresponding optical channel.

[0019] Therefore, it can be configured such that the image sensor directly follows the optical correction element, so that the imaging light rays emitted from the optical correction element are directly incident on the sensor surface without passing through another optical element, except for the cover glass that protects the sensor surface of the image sensor.

[0020] One particular design configuration involves the optical correction element having an incident surface and two spatially separated exit surfaces. That is, in this case, each of the two imaging ray paths (of the left and right optical channels) is separated by the correction element, so that each of the two imaging ray paths exits from each of the two exit surfaces of the correction element. Preferably, the correction element has a wavelength-selective mirror that guides wavelengths in a first wavelength range to the first exit surface of the correction element and wavelengths in a second wavelength range deviating from the first wavelength range to the second exit surface of the correction element. This allows for the sensory detection of one image in each of the two imaging ray paths generated by the two optical channels within two different wavelength ranges. Therefore, in this way, two stereoscopic images can be detected using the stereoscopic endoscope within two different wavelength ranges.

[0021] One particularly suitable design configuration for this purpose is that each of the aforementioned incident or exit surfaces of the optical correction element is formed by corresponding double glass wedges, wherein the double glass wedges are preferably designed symmetrically. The corresponding double glass wedges here constitute optical surfaces that are inclined relative to each other and are respectively designed to be flat. The optical surfaces can be inclined differently depending on the placement of the double glass wedges on the incident or exit side. In such a design, the corresponding imaging ray path can then extend through only one of the two optical surfaces, respectively.

[0022] This design of the optical correction element is particularly suitable for endoscopes having two spatially separated image sensors, each designed for imaging in different wavelength ranges. In this case, the imaging ray path of a first stereoscopic observation ending in the first image sensor can exit through the first exit surface of the optical correction element, and the imaging ray path of a second stereoscopic observation ending in the second image sensor can exit through the second exit surface of the optical correction element. Each of these two imaging ray paths can be defined here as a separate image center distance D1 or D2 on the sensor surface of the respective image sensor. Furthermore, two of these image center distances D1 and D2 can be made smaller than the stereo baseline B by means of the optical correction element.

[0023] The first wavelength range can, for example, have the visible spectrum (VIS). And the second wavelength range can have wavelengths outside the visible spectrum, especially in the near-infrared (NIR).

[0024] As previously mentioned, the optical correction element can have a wavelength-selective ray splitter. Here, two spatially separated image sensors can be configured with the ray splitter. In this case, as explained previously, corresponding imaging can be achieved using the two image sensors in two different wavelength ranges. Preferably, in such a design, the ray splitter spatially separates the imaging rays (generated by the two optical channels) of the corresponding imaging ray paths into a first imaging path on the left and a first imaging path on the right, and a second imaging path on the left and a second imaging path on the right. This allows for the sensing of images from two stereoscopic observations in different wavelength ranges.

[0025] In a design utilizing two imaging paths (each designed for stereoscopic observation), the optical correction element can be configured to move not only the orientation of at least one optical axis of the two first imaging paths but also the orientation of at least one optical axis of the two second imaging paths. This can be particularly designed such that the correction element not only adapts to, preferably reduces / has adapted to, preferably has reduced the first image center distance D1 belonging to the first imaging path, but also adapts to, preferably reduces / has adapted to, preferably has reduced the second image center distance D2 belonging to the second imaging path.

[0026] Therefore, when using such a ray separator and applying left and right imaging ray paths, there are four optical paths: two first imaging paths, one on the left and one on the right, both ending on the first image sensor, and two second imaging paths, one on the right and one on the left, both ending on the second image sensor. The ray separator can be designed in one piece, particularly by means of a prism design including wavelength-selective mirrors, or it can consist of multiple optical components (e.g., two such prisms, i.e., one prism for each optical channel of the endoscope).

[0027] The splitting into two first imaging paths and two second imaging paths can be achieved here using a wavelength-selective mirror of the ray splitter. A glass body can be attached to this mirror, specifically so that compensation can be achieved for the difference in optical path length between the first and second imaging paths.

[0028] Each of the two optical channels mentioned earlier in the endoscope may have a corresponding imaging optics, which includes an objective lens optics and a rear relay optics. Here, the relay optics can image the image generated by the objective lens optics from the intermediate image plane through the optical correction element onto the sensor surface of the at least one image sensor. If the optical correction element here has a ray splitter, the relay optics thus wavelength-dependently image one image each through the optical correction element onto the respective sensor surface of the correspondingly configured image sensor.

[0029] Preferably, the corresponding imaging optics may additionally include a steering prism disposed before the objective lens optics and a concave lens disposed before the steering prism. Thus, the endoscope can be designed to have strabismus.

[0030] Particularly preferred is the design of the optical correction element using at least two optical offset elements. These offset elements can be designed of the same type and / or complementary to each other. Furthermore, the offset elements can be implemented, particularly using complementary glass wedges. That is, this design allows the two optical offset elements to work together such that their respective optical axes move parallel after passing through the optical correction element. This can be particularly achieved by designing the two optical axes to extend with a reduced distance (after traversing the optical correction element) and thus the left and right image regions are close to each other on the sensor surface.

[0031] "Complementary" can be technically understood here as the two offset elements being designed such that the corresponding ray offsets caused by the offset elements mutually compensate for each other, so that the corresponding optical axes move parallel after passing through the optical correction element. The offset elements can be designed individually, either by means of refractive or diffractive elements, and combinations of such elements (also with refractive elements) can also be designed.

[0032] The at least two optical offset elements can preferably be applied to the incident and exit surfaces of the ray separator. In this case, it is also preferable to apply a third optical offset element to the exit surface of a glass body, wherein the glass body is mounted on a wavelength-selective mirror of the ray separator. This wavelength-selective mirror here constitutes the first exit surface of the ray separator. A second optical offset element can be applied to the second exit surface of the ray separator in this case.

[0033] In all the previously mentioned designs, the incident surface and the corresponding exit surface of the optical correction element can be oriented parallel to each other. However, here the incident surface and the exit surface of the optical correction element can extend differently relative to the sensor surface of the at least one image sensor, i.e., parallel or non-parallel. In both cases, the desired movement of the corresponding optical axis can be achieved.

[0034] Furthermore, in all the previously mentioned designs, the corresponding main ray of the corresponding imaging ray path can be inclined to the longitudinal axis of the endoscope as it passes through the optical correction element and extend parallel to the longitudinal axis after exiting the optical correction element.

[0035] According to one design, the corresponding principal ray (of the corresponding imaging ray path) can be deflected (rotated) (i.e., refracted) at least four times as it passes through the optical correction element. For example, the corresponding principal ray can first undergo a first optical refraction at the air / glass interface, then a second optical refraction at the glass / glass interface, then a third optical refraction at the glass / glass interface, and finally a fourth and final optical refraction at the glass / air interface as it passes through the optical correction element. Thus, the corresponding principal ray can move generally parallel to its axis.

[0036] A slightly different design, conversely, involves the primary ray being refracted twice at the internal glass / glass interface as it passes through the optical correction element, with the incident and exit surfaces of the optical correction element extending parallel to the sensor surface of the at least one image sensor. However, in this case, the primary ray enters the optical correction element but exits it without refraction. Other imaging rays incident obliquely onto the incident or exit surfaces of the optical correction element, however, may be deflected accordingly.

[0037] Regarding the ratio of the three-dimensional baseline B to the center distance D, according to the present invention, the following numerical range can be selected: D / B<0.95, preferably even D / B<0.90.

[0038] As mentioned earlier, optical correction elements can be implemented as refractive optical elements, especially by means of at least two glass wedges. In this case, it is preferable that the at least two glass wedges together cause at least one, and more preferably both, optical axes to be refractively offset such that the corresponding axes move in parallel.

[0039] Furthermore, for optimized imaging, it is preferable that the incident surfaces of the first glass wedges and the exit surfaces of the second glass wedges of the at least two glass wedges are oriented parallel to each other.

[0040] The interior angle of the corresponding glass wedge is preferably less than 5°, especially less than 3.5°.

[0041] The normal to the first incident surface of the optical correction element, that is, in particular the normal to the first incident surface of one of the glass wedges, can be oriented either parallel to or inclined to the respective optical axis. In both cases, a desired axial parallel movement of the corresponding optical axis can be achieved. Similarly, the normal to the last exit surface of the optical offset element, that is, in particular the normal to the last exit surface of one of the glass wedges, can also be oriented either parallel to or inclined to the respective optical axis.

[0042] According to the invention, the offset caused by the optical correction element in at least one or even both of the two optical axes can be designed such that the two image regions do not overlap on the sensor surface. Therefore, a safe region not used for imaging is maintained between the two image regions. However, this safe region can be designed to be relatively narrow. According to the invention, a width of at least 50 μm is suitable for this purpose, so as to also compensate for manufacturing variations.

[0043] If sufficient measures are taken to minimize stray light and mechanical tolerances are adequately controlled during assembly, it is also possible to design the corresponding offsets of at least one or even both optical axes caused by optical correction elements such that the two image regions overlap on the sensor surface in the overlapping region. Light then reaches this overlapping region from both the left and right channels. However, in such a case, smaller sub-image regions, each located within one of the two image regions, can also be used for imaging. Preferably, these sub-image regions can be selected rectangularly, thereby obtaining high-resolution rectangular individual images. Attached Figure Description

[0044] The invention will now be described in detail with reference to embodiments, but the invention is not limited to these embodiments. Other aspects of the invention may be obtained from the following description of preferred embodiments in conjunction with the general description, claims, and drawings. In the following description of different preferred embodiments of the invention, elements that are functionally consistent are given consistent reference numerals even in cases of different designs or shapes.

[0045] in:

[0046] Figure 1 A schematic diagram of a CIT endoscope according to the present invention as part of a video endoscope system is shown;

[0047] Figure 2 A strongly schematic view showing an imaging optics device for stereoscopic observation of an endoscope as known in the prior art;

[0048] Figure 3 Showing according to Figure 2 A schematic view of the sensor surface of the image sensor of an endoscope;

[0049] Figure 4 A strongly schematic view showing an imaging optics device for stereoscopic observation, the imaging optics device being designed in the distal end section of an endoscope according to the invention, which includes an optical correction element according to the invention;

[0050] Figure 5 Showing according to Figure 4 A top view of the sensor surface of the image sensor of the endoscope according to the present invention;

[0051] Figure 6 A strongly simplified, non-scale diagram showing the optical correction element in the sense of the present invention;

[0052] Figure 7 This illustrates another possible design for the optical correction element according to the invention;

[0053] Figure 8 A side view of another optical correction element according to the invention is shown, which can be used in an endoscope according to the invention, the endoscope being capable of sensing different spectral regions individually;

[0054] Figure 9 Show Figure 8 A perspective view of the optical correction element;

[0055] Figure 10 A schematic side view of the optical elements in the distal end section of the endoscope according to the invention is shown, and finally...

[0056] Figure 11 Another possible design according to the invention is shown, wherein the two image circles overlap. Detailed Implementation

[0057] Figure 1 A typical application scenario using the endoscope 1 according to the invention is illustrated. The endoscope 1 has an endoscope stem 32, with a handle portion 33 disposed at the proximal end of the endoscope stem, which the operator uses to position the endoscope. An image sensor 2 of the endoscope 1 is disposed in a distal end section 3 at the distal end of the endoscope stem 32, thus designing the endoscope as a so-called chip-in-the-tip (CIT) endoscope. The image signal generated by the image sensor 2 is transmitted to a camera control unit 34, which converts the signal into a video signal and transmits the video signal to a display unit 35 for display.

[0058] like Figure 2 As shown, it is already known in the prior art, as in Figure 1 The CIT endoscope 1 illustrated in the diagram comprises two optical channels 4a and 4b constructed using multiple optical elements. In this manner, each of the two optical channels 4a and 4b defines its corresponding imaging ray path 5a, 5b, which in turn... Figure 2 The image sensor 2 shown ends on the common sensor surface 7, so that a single image of the corresponding left or right side of the scene observed by the endoscope 1 is generated there.

[0059] If correct Figure 3As observed, the imaging ray path 5a of the right optical channel 4a produces the right image region 6a for imaging, and similarly, the imaging ray path 5b of the left produces the illustrated left image region 6b. Because the optical elements of the two channels 4a and 4b are designed with most of their optical components rotationally symmetrically, as is common in the prior art, two corresponding image circles 23a and 23b are generated on the sensor surface 7 by the corresponding imaging ray paths 5a and 5b. The centers of the image circles 23a and 23b simultaneously constitute the corresponding geometric image center points 8a and 8b of the two image regions 6a and 6b. Pixels in image regions 6a and 6b can be read here to generate a corresponding single image in a disk-shaped format; alternatively, only pixels in sub-image regions 46a and 46b marked with rectangular frames can be read to generate rectangular images.

[0060] If correct Figure 2 As observed, each of the two imaging ray paths 5a and 5b defines a corresponding optical axis 10a, 10b on the incident side, which extends through corresponding optical channels 4a, 4b. These two optical axes 10a, 10b have a distance B on the incident side, which defines the stereo baseline of the endoscope 1. A stereoscopic image can be obtained using the two single images simultaneously sensed and detected by the image sensor 2, wherein the size of the stereo baseline B is determined, and the strength of the spatial impression obtained by the observer when viewing these stereoscopic images is determined. This is because the two optical axes 10a and 10b are located at a distance B on the incident side. Figure 2 In the example, the two optical axes 10a and 10b extend strictly parallel to the image sensor 2, so the distance D between them and the sensor surface 7 is the same as the stereo baseline B, thus applying D = B.

[0061] Figure 4 A first example of a CIT endoscope 1 for stereoscopic observation according to the present invention is shown, wherein the two optical channels 4a, 4b (similar to...) can also be seen here. Figure 2 The two optical channels form corresponding imaging ray paths 5a and 5b, which terminate on the shared sensor surface 7 of the image sensor 2. Figure 4 The optical arrangement structure shown is disposed on the distal end section 3 of the endoscope 1, as in Figure 1 As shown in the diagram. However, compared to... Figure 2 The prior known design, in Figure 4 As can be seen, an optical correction element 11 is disposed between the two optical channels 4a and 4b and the image sensor 2. Figure 2In the example, the optical correction element 11, which is constructed in two parts by two correction elements 11a and 11b, can be seen to move the two optical axes 10a and 10b parallel to each other, such that the previously explained image center distance D is now smaller than the stereo baseline B on the incident side.

[0062] like Figure 5 As shown, with the same sensor size, the two image circles 23a and 23b can now be designed larger and closer to each other based on the reduced image center distance D, so that only a negligible gap g' remains between the two image circles 23a and 23b. Based on the absolutely magnified image circles 23a and 23b, more pixels can now be read for the corresponding single image, thereby improving image resolution.

[0063] exist Figure 4 As can be seen, the corresponding imaging optical devices 24 constituting the corresponding optical channels 4a and 4b each have an objective lens optical device 25 and a rear-mounted relay optical device 26. The corresponding relay optical device 26 images the corresponding intermediate image from the shown intermediate image plane 30 onto the sensor surface 7 through the optical correction element 11. Furthermore, it can be seen that a steering prism 27 is positioned before the objective lens optical device 25, and the steering prism receives the imaging rays from the concave lens 28 positioned before it. Figure 10 As illustrated, the strabismus of the two optical channels 4a and 4b for endoscope 1 can be designed in this way.

[0064] The entire corresponding imaging optics 24 is thus positioned before the optical correction element 11. The imaging light rays emitted from the optical correction element 11 therefore only need to pass through the cover glass 22 of the image sensor 2 (e.g., the contrast glass) before hitting the sensor surface 7. Figure 6 and Figure 7 ).

[0065] Figure 6 and 7 This illustrates a possible first design of the optical correction element 11 according to the invention, and more precisely, as a refractive element. Figure 6 and 7As can be seen in the two designs, the optical correction element 11 is designed using two complementary optical offset elements 37a and 37b. These elements are implemented using glass wedges 16a and 16b of the same type, which are applied to the flat end face of the glass body 40. The front and rear glass wedges 16a and 16b work together to cause the optical axis 10a of the illustrated imaging ray path 5a of the right optical channel 4a, or the principal ray 20a shown, to be moved parallel to the negative x-direction. If needed, another additional parallel movement of the principal ray 20b therein can be produced by the mirror-symmetric design of another optical correction element 11 in the left optical channel 4b, which is then moved parallel to the positive x-direction, resulting in the effect shown in the diagram. Figure 4 In the case illustrated, the two main rays 20a and 20b (which extend along the optical axis) are close to each other.

[0066] exist Figure 6 and 7 As can be seen in the two design examples, the corresponding axis 10a moves parallel after passing through the optical correction element 11, thereby forcibly reducing the distance to the adjacent optical axis of the adjacent optical channel. Figure 6 and 7 In both examples, the corresponding incident surface 17 and the exit surface 18 of the optical correction element 11 are also oriented parallel to each other. Of course, only in... Figure 7 In the example, the incident surface 17 also extends parallel to the sensor surface 7 of the image sensor 2, while Figure 6 In the example, the incident surface 17 and the parallel exit surface 18 are not oriented parallel to the sensor surface 7. Therefore, the main ray 20a enters the sensor surface 7. Figure 7 In the correction element 11, it does not refract initially, but only at the glass / glass interface inside the glass body 40 (with refractive index n2) and the two glass wedges 16a and 16b (each with refractive index n1).

[0067] In contrast, Figure 6 In the example, the main ray 20a entering the optical correction element 11 is deflected four times, wherein, Figure 6 The detailed view on the left shows the first optical refraction at the first air glass interface, where the incoming principal ray 20a is initially refracted toward the incident normal 36. If followed by... Figure 6 The trajectory of the main ray 20a shows the second optical refraction at the glass / glass interface, the third optical refraction at the glass / glass interface, and the fourth and final optical refraction when exiting from the exit surface 18 of the correction element 11.

[0068] Figure 8 Another particularly advantageous design is shown, in which the optical correction element 11 has an incident surface 17 and two spatially separated exit surfaces 18a and 18b. Also visible is a wavelength-selective mirror 44 that selectively divides the incident main rays 20a / 20b into a first imaging path 14a / 14b and a second imaging path 15a / 15b (also shown in comparison to...). Figure 9 (Perspective view). Correspondingly, in Figure 8 In the example, a corresponding image sensor 2a, 2b is configured for each of the two exit surfaces 18a and 18b. Therefore, these spatially separated image sensors 2a, 2b (the distances between the image sensors and the corresponding exit surfaces 18a, 18b are not shown to scale) can achieve imaging in two different wavelength ranges because the visible wavelength (VIS) passes through mirror 44 and is thus sensed by the first image sensor 2a. In contrast, fluorescence wavelengths in the near-infrared (NIR) are reflected by mirror 44 and then re-reflected by another (fully reflective) second mirror 42, so that they finally exit from the optical correction element 11 from the second exit surface 18b. These fluorescence wavelengths are therefore sensed by the second image sensor 2b, which applies to the two imaging ray paths 5a and 5b generated by the two optical channels 4a, 4b. Because the two imaging ray paths 5a and 5b, after wavelength selection separation, reach not only the first image sensor 2a but also the second image sensor 2b, as in... Figure 9 This can be clearly seen in the text.

[0069] Therefore, by means of the wavelength-selective mirror 44, in Figure 8 and 9 The ray separator 13 shown in the figure separates the imaging rays of the corresponding imaging ray paths 5a or 5b into a first imaging path 14a on the right and a first imaging path 14b on the left, both of which end in the first image sensor 2a, and a second imaging path 15a on the left and a second imaging path 15b on the right, both of which end in the second image sensor 2b.

[0070] As in Figure 6 and 7 In the example, also Figure 8 and 9 In the example, the correction element 11 is implemented using an optical offset element 37. Thus, in... Figure 8 and 9The wavelength-selective ray splitter 13, previously described, is seen as part of the optical correction element 11. A double glass wedge 43 here forms an incident surface 17 and two spatially separated exit surfaces 18a and 18b for each of the total four imaging paths 14a, 14b, 15a, and 15b. The corresponding double glass wedge 43 here has two flat optical surfaces 45a and 45b, which are inclined relative to each other. Figure 8 and 9 Therefore, the design corresponds to Figure 6 The design is such that the corresponding main rays 20 of the corresponding imaging ray paths 5a / 5b are also refracted when incident on the incident surface 17 of the correction element 11.

[0071] In consideration Figure 6 As can be understood from the working principle shown and the orientation of the symmetrically designed double glass wedges 43, based on the combined action of the two glass wedges 43 on the incident surface 17 and the first exit surface 18a, the optical correction element 11 moves the orientation of the two optical axes of the two first imaging paths 14a and 14b ending on the first image sensor 2a such that the corresponding first image center distance D1 is smaller than the stereo baseline B on the incident side. The same applies to the second image center distance D2 in the region of the second image sensor 2b, since here the two glass wedges 43 act correspondingly in the region of the incident surface 17 and the region of the second exit surface 18b.

[0072] refer to Figure 8 and 9 It should also be mentioned that, for example, the lower double glass wedge 43 in the region of the second exit surface 18b of the optical correction element 11 could also be replaced by one or two diffractive elements. Alternative elements for applying diffraction or refraction are also conceivable, for example, by tilting the upper second mirror 42 such that the desired ray deflection is achieved, so as to move the corresponding principal ray in parallel. Thus, in this case, the deflection is achieved (at least partially) using reflective optical elements.

[0073] In addition, Figure 8 and 9 As can be clearly seen, the individual glass body 40 is mounted on the wavelength-selective mirror 44 of the ray separator 13, because this compensates for the optical path length difference. The third optical deflection element 37c, which is formed by one of the three double glass wedges 43, is applied here to the exit surface 41 of the glass body 40.

[0074] exist Figure 8 and 9In the example, as long as the correctly configured surfaces for the corresponding imaging paths 14a / 14b / 15a / 15b are observed, the corresponding incident surface 17 and the associated exit surface 18 are also oriented parallel to each other. Furthermore, it can be seen (as in...) Figure 6 In the example, the incident and exit surfaces 17 and 18 of the optical correction element 11 are not oriented parallel to the corresponding sensor surfaces 7a or 7b of the corresponding image sensors 2a / 2b. However, after passing through the optical correction element 11, the corresponding main rays 20a and 20b of the two paths 14a and 14b extend strictly along the y-direction corresponding to the longitudinal axis 21 of the endoscope (see example). Figure 8 and Figure 1 ).

[0075] Figure 11 Another design according to the invention is shown, which is possible provided that mechanical tolerances are controlled sufficiently well during endoscope assembly, and in this design, two image circles overlap on sensor surface 7 in the illustrated overlapping region 47. Such a design enables an additional gain in image resolution because the rectangular, non-overlapping sub-image regions 46a, 46b on image sensor surface 7 (which can also be read to generate a rectangular image) and Figure 5 The examples are relatively large; the proportions of these rectangular sub-image regions 46a and 46b on sensor surface 7 are also large, thus more pixels are available for a single image of the corresponding rectangle. Of course, in such a design, sufficient measures should be taken to minimize stray light in order to avoid optical crosstalk between regions 46a and 46b. Furthermore... Figure 11 As can be seen, the two sub-image regions 46a and 46b are further separated from each other (i.e. advantageously at least by the x-width of the overlapping region 47) for this reason, that is, they do not overlap.

[0076] In summary, to improve the image quality of stereoscopic images recorded using a CIT endoscope 1, it is proposed to place an optical correction element 11 between two parallel, identically designed optical channels 4a and 4b for imaging and the image sensor 2 for imaging. This optical correction element moves the corresponding principal rays 20a and 20b of the respective optical channels 4a and 4b in such a parallel manner that the imaging ray paths 5a and 5b generated through the two optical channels 4a and 4b are brought closer to each other. As a result, the image center distance D between the image regions 6a and 6b on the sensor surface 7 of the image sensor 2 for two single images can be reduced compared to the stereo baseline B defined by the two optical channels 4a and 4b on the incident side, thereby achieving higher image resolution (comparison). Figure 9 ).

[0077] List of reference numerals

[0078] 1 Endoscope

[0079] 2 image sensors (set in 3)

[0080] 3(1) distal end section

[0081] 4 optical channels (formed by imaging optics)

[0082] 5. Imaging ray path (extended through 4 / through 4 defined)

[0083] Image area 6 (on 7)

[0084] 7(2) sensor surface

[0085] 8(6) geometric image center point

[0086] 9 Image center distance

[0087] 10. Optical axis (center of definition 5)

[0088] 11 Optical Correction Components

[0089] 12. Stereobaseline B

[0090] 13-ray splitter (splits 5 rays into two optical paths)

[0091] 14 First imaging path (e.g., for white light imaging (VIS))

[0092] 15. Second imaging path (e.g., for fluorescence imaging (FI))

[0093] 16 glass wedges

[0094] 17 (11) incident surface

[0095] 18 (11) exit surface

[0096] 19 Safe Zones

[0097] 20(5) main rays

[0098] 21(1) longitudinal axis

[0099] 22. Cover glass (for dust and mechanical load protection 7)

[0100] 23 Image Circle

[0101] 24 Imaging Optical Device

[0102] 25 Objective Lens Optical Setup

[0103] 26 Relay Optical Devices

[0104] 27 Steering Prism

[0105] 28 concave lens

[0106] 29 Entrance windows

[0107] 30 intermediate image plane

[0108] 31 organizations (using 1 observation)

[0109] 32 Endoscope Rod

[0110] 33 handle part

[0111] 34. Camera control unit (CCU)

[0112] 35 display units

[0113] 36 Incident Normal

[0114] 37 Optical Offset Elements

[0115] 38 (13) incident surface

[0116] 39 (13) exit surface

[0117] 40 Vitreous

[0118] 41 (40) exit surface

[0119] 42 (13; designed for total internal reflection) mirror

[0120] 43 Symmetrical double glass wedges

[0121] 44(13) wavelength-selective mirrors

[0122] 45 square optical surface

[0123] 46 Rectangular sub-image regions

[0124] 47 (overlapping area of ​​6a and 6b on 7)

Claims

1. A cutting-edge chip endoscope for stereoscopic observation (1), including - At least one distal image sensor (2), said distal image sensor being disposed in the distal end section (3) of said endoscope (1), and - Two optical channels (4a, 4b) with corresponding imaging ray paths (5a, 5b), the optical channels generating a right image region (6a) and a corresponding left image region (6b) for imaging on the sensor surface (7) of the at least one image sensor (2). -in, The corresponding geometric image center points (8a, 8b) of the two image regions (6a, 6b) define the image center distance D(9), and -In this context, each of the two imaging ray paths (5a, 5b) defines a corresponding optical axis (10a, 10b) on the incident side, the optical axis extending through the corresponding optical channel (4a, 4b), and - Wherein, the two optical axes (10a, 10b) are set at a distance B on the incident side, the distance defining the stereo baseline (12) of the endoscope (1), The endoscope (1) is characterized in that it has an optical correction element (11). - The optical correction element is disposed between the two optical channels (4a, 4b) and the at least one image sensor (2) and - The optical correction element causes at least one of the two optical axes (10a, 10b), preferably both optical axes, to move parallel to each other, so that it is suitable for D <B。 2. The endoscope (1) according to claim 1, wherein, The corresponding total imaging optical device (24) of the corresponding optical channel (4a, 4b) is arranged in front of the optical correction element (11) along the direction of the corresponding imaging ray path (5a, 5b).

3. The endoscope (1) according to claim 1, wherein, The optical correction element (11) has an incident surface (17) and two spatially separated exit surfaces (18a, 18b). - Preferably, the correction element (11) further has a wavelength-selective mirror (44) that guides wavelengths in a first wavelength range to a first exit surface (18a) of the correction element (11) and wavelengths in a second wavelength range deviating from the first wavelength range to a second exit surface (18b) of the correction element (11). - Particularly preferred, each of these incident or exit surfaces (17, 18a, 18b) is formed by corresponding, preferably symmetrically designed double glass wedges (43), which form two relatively inclined and respectively flat optical surfaces (45a, 45b). -In particular, the corresponding imaging ray paths (5a, 5b) extend through only one of the two optical surfaces (45a, 45b).

4. The endoscope (1) according to any one of the preceding claims, wherein, The optical correction element (11) has a wavelength-selective ray separator (13). In particular, two spatially separated image sensors (2a, 2b) are configured for the ray separator (13), thereby enabling corresponding imaging in two different wavelength ranges using the two image sensors (2a, 2b). - Preferably, the ray separator (13) spatially separates the imaging rays of the corresponding imaging ray paths (5a, 5b) into - The first imaging path on the right (14a) and the first imaging path on the left (14b) and - The second imaging path on the right (15a) and the second imaging path on the left (15b).

5. The endoscope (1) according to the preceding claim, -in, The optical correction element (11) not only moves the orientation of at least one optical axis of the two first imaging paths (14a, 14b) but also moves the orientation of at least one optical axis of the two second imaging paths (15a, 15b). -In particular, the movement is such that not only is the first image center distance D1 belonging to the first imaging path (14a, 14b) adapted and preferably reduced, but the second image center distance D2 belonging to the second imaging path (15a, 15b) is also adapted and preferably reduced.

6. The endoscope (1) according to any one of the preceding claims, wherein, Each of the two optical channels (4a, 4b) has a corresponding imaging optical device (24), which includes an objective lens optical device (25) and a relay optical device (26). -In particular, the relay optics (26) images the image generated by the objective optics (25) from the intermediate image plane (30) through the optical correction element (11) onto the sensor surface (7) of the at least one image sensor (2). - Preferably, the corresponding imaging optics (24) additionally has a steering prism (27) disposed in front of the objective lens optics (25) and a concave lens (28) disposed in front of the steering prism (27), so that the endoscope (1) is designed to be squinting.

7. The endoscope (1) according to any one of the preceding claims, in, The optical correction element (11) is designed using at least two, preferably identical and / or complementary, optical offset elements (37a, 37b), especially using at least two complementary glass wedges (16a, 16b). - Preferably, the two optical offset elements (37a, 37b) work together to cause the corresponding optical axes (10a, 10b) to move in parallel after passing through the optical correction element (11), in particular so that the two optical axes (10a, 10b) extend by a reduced distance and the left image region and the right image region (6a, 6b) are close to each other on the sensor surface (7).

8. The endoscope (1) according to claims 3 and 5, wherein, The at least two optical offset elements (37a, 37b) are applied to the incident surface (38) and the exit surface (39) of the ray separator (13). - Preferably, a third optical offset element (37c) is applied to the exit surface (41) of a glass body (40), which is mounted on a wavelength-selective mirror (44) of the ray separator (13), the wavelength-selective mirror (44) forming the first exit surface (39a) of the ray separator (13).

9. The endoscope (1) according to any one of the preceding claims, -In this embodiment, the incident surface (17) and the corresponding exit surface (18) of the optical correction element (11) are oriented parallel to each other. -In particular, the incident surface (17) and the exit surface (18) of the optical correction element (11) are relative to the sensor surface (7) of the at least one image sensor (2). - Parallel or -not parallel Extension and / or -in, The corresponding main rays (20a, 20b) It is inclined to the longitudinal axis (21) of the endoscope (1) as it passes through the optical correction element (11) and extends parallel to the longitudinal axis (21) of the endoscope (1) after exiting the optical correction element (11).

10. The endoscope (1) according to any one of the preceding claims, -In this context, the corresponding principal rays (20a, 20b) are deflected at least four times, in particular refracted at least four times, and / or -in, The corresponding main rays (20a, 20b) first pass through the optical correction element (11) - It undergoes the first optical refraction at the air / glass interface, and then... - A second optical refraction occurs at the glass / glass interface, followed by -At the glass / glass interface, a third optical refraction occurs and finally... - It undergoes the fourth and final optical refraction at the glass / air interface. Therefore, the corresponding principal rays (20a, 20b) generally move parallel to their axes.

11. The endoscope (1) according to any one of claims 1 to 7, wherein, The corresponding main rays (20a, 20b) are refracted twice at the internal glass / glass interface as they pass through the optical correction element (11), and the incident surface (17) and the exit surface (18) of the optical correction element (11) extend parallel to the sensor surface (7) of the at least one image sensor (2).

12. The endoscope (1) according to any one of the preceding claims, -The ratio of the stereo baseline B(12) and the image center distance D(9) is selected as follows: D / B < 0.95, preferred application: D / B < 0.

90.

13. The endoscope (1) according to any one of the preceding claims, wherein, At least one of the two optical axes (10a, 10b) is offset by the optical correction element (11) such that the two image regions (6a, 6b) do not overlap on the sensor surface (7), but instead retain a safety region (19) with a width of at least 50 μm between the two image regions (6a, 7b), which is not used for imaging.

14. The endoscope (1) according to any one of claims 1 to 12, wherein, The offset caused by at least one of the two optical axes (10a, 10b) through the optical correction element (11) is designed such that the two image regions (6a, 6b) overlap in the overlap region (47) on the sensor surface (7). However, in particular, only smaller, preferably rectangular sub-image regions (46a, 46b) are used for imaging within the two image regions (6a, 6b).

Images