Endoscopic optical systems and stereoscopic endoscopes

Abstract

This application provides an endoscopic optical system, including a first mirror group, a second mirror group, and a light-directing device. The first mirror group includes at least one lens with optical power. The second mirror group includes at least one lens with optical power. The light-directing device is disposed between the first and second mirror groups, and includes a first optical mirror body. The first optical mirror body includes a first surface, a second surface, and a third surface, and the first surface is provided with an optical film group. The light propagation of the endoscopic optical system satisfies the following conditions: normally incident light rays are incident on the second surface through the first mirror group and the first surface, undergo one reflection, return to the first surface, and then are incident on the second mirror group from the first surface to form an image on the image side; large-angle incident light rays are incident on the second surface through the first mirror group and the first surface, undergo at least two reflections, return to the first surface, and then are transmitted from the first surface to the object side. The endoscopic optical system of this application can effectively eliminate ghost images and reduce stray light.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, and more specifically to an endoscope optical system and a stereo endoscope. Background Technology

[0002] Minimally invasive surgery has become the development trend in all fields of surgical medicine worldwide. It offers numerous advantages, including less trauma to patients, reduced intraoperative pain, and shorter postoperative recovery time, and its application is becoming increasingly widespread.

[0003] Medical endoscopes are used to observe internal body cavities, allowing doctors to directly observe the morphology of internal organs and tissues, providing real-time images of the surgical site. Endoscopes have undergone extensive development and improvement; current rigid endoscopes not only offer high-quality imaging but also enable color image capture and recording. Coupled with advancements in endoscopic surgical instruments and accessories, they are now widely used in the medical field. Furthermore, continuous improvements in lens manufacturing technology have enabled the outer diameter of lenses to be reduced to within 2mm, significantly minimizing the overall size of the endoscope, thus reducing surgical incisions and patient discomfort during and after surgery. Summary of the Invention

[0004] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0005] To at least partially solve the above problems, a first aspect of this application provides an endoscope optical system, comprising:

[0006] An endoscope optical system, characterized in that it comprises:

[0007] The first lens group includes at least one lens with optical power;

[0008] The second lens group includes at least one lens with optical power, and

[0009] A light steering device is disposed between the first mirror group and the second mirror group. The light steering device includes a first optical mirror body, which includes a first surface, a second surface and a third surface. An optical film group is disposed on the first surface.

[0010] The light propagation of the endoscope optical system satisfies:

[0011] Normal angle incident light passes through the first lens group, is incident from the first surface to the second surface, is reflected once by the second surface back to the first surface, is reflected from the first surface to the third surface, and is incident on the second lens group after passing through the third surface to reach the image side for imaging;

[0012] After passing through the first mirror group, the large-angle incident light rays are incident from the first surface to the second surface, and then reflected at least twice by the second surface back to the first surface. Finally, the large-angle incident light rays are transmitted from the first surface to the object side.

[0013] Optionally, the light steering device further includes a reflective polarizing film and a phase retarder, the reflective polarizing film and the phase retarder being sequentially disposed on the first surface along the optical path direction, and the optical axis of the phase retarder being at an angle θ with respect to the transmission axis of the reflective polarizing film, where 0 < θ < π / 2.

[0014] Optionally, the angle between the optical axis of the phase retardation film and the transmission axis of the reflective polarizing film is 45°.

[0015] Optionally, the reflective polarizing film transmits light in the same direction as the transmission axis, and reflects or absorbs light perpendicular to the transmission axis.

[0016] Optionally, the phase delay plate is a quarter-wave plate.

[0017] Optionally, the optical film assembly further includes a reflective film disposed on the second surface.

[0018] Optionally, the reflective film is a reflective film with low transmittance and high reflectance.

[0019] Optionally, the reflective film is a silver reflective film or an aluminum reflective film.

[0020] Optionally, the light steering device further includes a second optical mirror and a third optical mirror, wherein the second optical mirror and the third optical mirror are respectively disposed on the light-inlet side and the light-outlet side of the first optical mirror.

[0021] Optionally, a transmissive polarizing film layer is provided on the light-incoming surface of the second optical mirror, wherein the transmission axis direction of the transmissive polarizing film layer is the same as the transmission axis direction of the reflective polarizing film layer.

[0022] Optionally, a transmissive polarizing film is provided between the light-emitting side surface of the second optical mirror and the reflective polarizing film, wherein the transmission axis direction of the transmissive polarizing film is the same as that of the reflective polarizing film.

[0023] Optionally, any two of the transmissive polarizing film, the second optical mirror, the reflective polarizing film, the phase retarder, the first optical mirror, the reflective film, and the third optical mirror are tightly bonded together.

[0024] Optionally, the first lens group includes a first lens, which is a negative power lens; the object side of the first lens is planar and the image side is concave.

[0025] Optionally, the second lens group includes lenses arranged sequentially from the object side to the image side:

[0026] The third lens has a plane on its object-side surface.

[0027] The fourth lens has both its object-side and image-side surfaces being convex, and it is a positive power lens.

[0028] The fifth lens has both its object-side and image-side surfaces as convex surfaces, and is a positive power lens.

[0029] The sixth lens has both its object-side and image-side surfaces concave, and it is a negative power lens.

[0030] Optionally, the fifth lens is cemented to the sixth lens.

[0031] A second aspect of this application provides a stereoscopic endoscope, including the aforementioned optical system; and,

[0032] An image sensor, disposed on the image side of the optical system, is used to convert light signals transmitted through the optical system into electrical signals. Attached Figure Description

[0033] The following drawings, illustrating embodiments of this application, are incorporated herein by reference and are used to understand this application. The drawings illustrate embodiments of this application and their descriptions, serving to explain the principles of this application. In the drawings,

[0034] Figure 1 This is a schematic diagram of a preferred embodiment of the light steering device of this application;

[0035] Figure 2 for Figure 1 An exploded view of the light steering device shown.

[0036] Figure 3 This is a schematic diagram of an optical system according to a preferred embodiment of this application;

[0037] Figure 4 This is a schematic diagram of an optical system according to another preferred embodiment of this application;

[0038] Figure 5 This is a ray path diagram in an optical system; in the diagram, ray1 is a normal imaging ray path, and ray2 is an abnormal ray path.

[0039] Figure 6 for Figure 5 Schematic diagram of ray 1 ray path decomposition;

[0040] Figure 7 for Figure 5 A schematic diagram of the ray 2 path decomposition; and

[0041] Figure 8 This is a schematic diagram of an optical system according to a preferred embodiment of this application.

[0042] Explanation of reference numerals in the attached figures

[0043] 100: First lens

[0044] 200: Light steering device

[0045] 210: First optical mirror body

[0046] 220: Second optical mirror

[0047] 230: Third optical mirror

[0048] 240: Transmissive polarizing film layer

[0049] 250: Reflective polarizing film layer

[0050] 260: Phase Delay Film

[0051] 270: Reflective film

[0052] 300: Third lens

[0053] 400: Fourth Lens

[0054] 500: Fifth Lens

[0055] 600: Sixth Lens

[0056] S11: Fourth Surface

[0057] S12: Fifth Surface

[0058] S21: First surface

[0059] S22: Second surface

[0060] S23: Third Surface

[0061] S31: Sixth Surface

[0062] S32: Seventh Surface Detailed Implementation

[0063] In the following description, numerous specific details are set forth to provide a more thorough understanding of this application. However, it will be apparent to those skilled in the art that embodiments of this application may be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with embodiments of this application.

[0064] In this document, ordinal numbers such as “first” and “second” used in this application are merely identifiers and do not have any other meaning, such as a specific order. Moreover, for example, the term “first component” does not imply the existence of a “second component”, and the term “second component” does not imply the existence of a “first component”.

[0065] In this article, terms such as "up," "down," "front," "back," "left," and "right" are used only to indicate the relative positional relationship between related parts, rather than to define the absolute position of these related parts.

[0066] In this document, terms such as “equal” and “same” are not strict mathematical and / or geometric limitations, but also include errors that are understandable to those skilled in the art and permissible in manufacturing or use.

[0067] Unless otherwise stated, the numerical ranges in this document include not only the entire range within its two endpoints, but also the subranges contained therein.

[0068] Endoscopes have zero-degree and non-zero-degree viewing angles. For endoscopes with non-zero-degree viewing angles, rotating the endoscope body provides not only axial vision but also a wider off-axis field of view compared to a zero-degree viewing angle, making them frequently used in surgical procedures. For non-zero-degree viewing angle endoscopes, whether electronic or optical, the deflection of the light path is achieved by using a steering prism system at the tip of the objective lens to reach the designed viewing angle.

[0069] Existing endoscopes with non-zero angle of view can achieve a clear image of normal incident light after a single reflection within the steering prism. However, when light is incident at large angles, secondary or multiple reflections occur at the reflecting surface of the steering prism, creating noticeable ghost images in the imaging area. In certain applications, this can interfere with the surgeon's vision. Therefore, reducing or eliminating secondary reflections is crucial for minimizing visual interference and improving surgical outcomes.

[0070] like Figure 8As shown, this application provides an endoscope optical system, including a first mirror group, a second mirror group, and a light steering device 200. The first mirror group includes at least one lens with optical power. The second mirror group includes at least one lens with optical power. The light steering device 200 is disposed between the first and second mirror groups and is used to control the propagation direction of the light beam, so that the light can be accurately transmitted to the target position. The light steering device 200 includes a first optical mirror body 210, which includes a first surface S21, a second surface S22, and a third surface S23. An optical film group is disposed on the first surface. The light propagation of the endoscope optical system satisfies the following: normally incident light enters the first mirror group through the first surface S21 and then the second surface S22, is reflected once by the second surface S22 back to the first surface S21, is reflected by the first surface S21 to the third surface S23, and is then directed from the third surface S23 to the second mirror group, and finally enters the image sensor for imaging. A large-angle incident light beam is incident from the first mirror group through the first surface S21 to the second surface S22, and then reflected at least twice by the second surface S22 back to the first surface S21 before being transmitted to the object side through the first surface S21. In this application, optical power refers to the lens's ability to focus a light beam, which can be adjusted by factors such as lens curvature, thickness, refractive index, and distance.

[0071] like Figures 3 to 4 In this application, by setting different film layers on the surface of the steering prism, when the incident angle is too large, the polarization direction of the light is changed, so that the outgoing light is reflected or absorbed and cannot pass through the third surface S23, thereby preventing it from forming an image on the image plane and thus avoiding the generation of ghost images.

[0072] In some embodiments of this application, the light steering device 200 further includes a reflective polarizing film layer 250 and a phase retarder 260. The reflective polarizing film layer 250 and the phase retarder 260 are sequentially disposed on the first surface S21 along the optical path direction. An angle θ exists between the optical axis of the phase retarder 260 and the transmission axis of the reflective polarizing film layer 250, where 0 < θ < π / 2. The reflective polarizing film layer 250 is an element similar to a polarizing mirror, allowing light of a specific polarization direction to pass through while reflecting light of other polarization directions. By disposing the reflective polarizing film layer 250 on the first surface S21, a portion of the incident light can be reflected back, while allowing another portion to pass through. The phase retarder 260 is an optical element used to adjust the phase of light. By adjusting the angle between the optical axis of the phase retarder 260 and the transmission axis of the reflective polarizing film layer 250, the polarization state of the light passing through these two elements can be adjusted.

[0073] In some embodiments of this application, the optical axis of the phase retardation film 260 is at an angle of 45 degrees to the transmission axis of the reflective polarizing film layer 250. The linearly polarized light passing through the reflective polarizing film layer 250 is converted into circularly polarized light after passing through the phase retardation film 260.

[0074] When the incident angle is too large, the polarization direction of the light can be changed by setting a reflective polarizing film layer 250 and a phase retardation film 260 on the first surface, thereby causing some of the outgoing light to be reflected or absorbed, avoiding the formation of an unclear image on the image plane. The reflective film 270 set on the second surface S22 can be used to further reflect the incident light. This can enhance the beam steering effect, allowing the light to be transmitted to the target position more effectively. The reflective film 270 can also work in conjunction with the preceding optical elements to further adjust the propagation direction of the light. In this embodiment, through the synergistic effect of the above-mentioned optical elements, the propagation direction and focusing effect of the beam can be controlled more effectively, improving the image quality. That is, when the incident angle is too large, by changing the polarization direction of the light, it is prevented from forming an image on the image plane, eliminating stray light and providing a clear image, providing reliable support for endoscopic applications.

[0075] In some embodiments of this application, the reflective polarizing film layer 250 transmits light rays in the same direction as the transmission axis (i.e., P-rays) and reflects or absorbs light rays perpendicular to the transmission axis (i.e., S-rays). When incident light shines on the reflective polarizing film layer 250, light rays with the P-component polarization direction can pass through the film layer, while light rays with the S-component polarization direction will be reflected. Therefore, the direction of the transmission axis can be adjusted as needed to transmit or reflect polarized light in a specific direction, thereby adjusting the polarization state of the incident light.

[0076] In some embodiments of this application, the phase retardation plate 260 is a quarter-wave plate. Polarized light is converted into elliptically polarized light or circularly polarized light after passing through a quarter-wave plate once. If linearly polarized light passes through a quarter-wave plate twice consecutively, the polarization direction of the linearly polarized light will be deflected by 90°. For example, P-light will be converted into S-light after passing through a quarter-wave plate twice consecutively. By placing the quarter-wave plate between the reflective polarizing film layer 250 and the reflective film layer 270, the polarization direction of the polarized light is deflected by 90° after passing through the quarter-wave plate twice, and then it can be reflected by the reflective polarizing film layer 250.

[0077] In some embodiments of this application, the reflective film 270 is a low-transmittance, high-reflectance reflective film 270. When incident light shines on the reflective film 270, some of the light interferes between the film layers, causing some light to be reflected while the rest is transmitted. By precisely controlling the thickness and refractive index of the film layers, the reflective film 270 can have specific reflectivity and transmittance. In this embodiment, the reflective film 270 reflects all the light incident on it. Specifically, the reflective film 270 is a low-transmittance, high-reflectance reflective film 270 such as a silver-plated reflective film or an aluminum reflective film. By improving the reflective ability of the reflective film 270, the brightness of the transmitted light is increased.

[0078] like Figures 1 to 2 As shown, in some embodiments of this application, the light steering device 200 further includes a second optical mirror 220 and a third optical mirror 230. The second optical mirror 220 and the third optical mirror 230 are respectively disposed on the light-incoming side (i.e., the first surface S21) and the light-outcoming side (the second surface S22) of the first optical mirror 210, and the second optical mirror 220 and the third optical mirror 230 are used to support the first optical mirror 210. In this application, the optical mirrors do not need to be glued together, and the process is relatively simpler.

[0079] In some embodiments of this application, a transmissive polarizing film layer 240 is provided on the light-incident surface of the second optical mirror 220, and the transmission axis direction of the transmissive polarizing film layer 240 is the same as the transmission axis direction of the reflective polarizing film layer 250. The transmissive polarizing film layer 240 and the reflective polarizing film layer 250 are used together to enhance the polarization effect. By adjusting the transmission axis direction of the two films, the transmission directions of the transmissive polarizing film layer 240 and the reflective polarizing film layer 250 can be made the same. That is, when polarized light passing through the transmissive polarizing film layer 240 is incident on the reflective polarizing film layer 250, the polarization direction remains unchanged.

[0080] In some embodiments of this application, a transmissive polarizing film 240 is provided between the light-emitting side surface of the second optical mirror 220 and the reflective polarizing film 250, and the transmission axis direction of the transmissive polarizing film 240 is the same as the transmission axis direction of the reflective polarizing film 250.

[0081] Based on the above embodiments, any two of the following components—transmissive polarizing film 240, second optical mirror 220, reflective polarizing film 250, phase retardation film 260, first optical mirror 210, reflective film 270, and third optical mirror 230—are tightly bonded together. By tightly bonding multiple components, the transmitted light does not pass through air gaps, improving reliability in complex environments. The tight bonding of multiple components also reduces internal reflection and scattering, thereby reducing light loss, improving beam transmission efficiency, and increasing imaging brightness.

[0082] In some embodiments of this application, the first lens group includes a first lens 100, which is a negative power lens; the object-side surface of the first lens 100 is planar, and the image-side surface is concave. By designing the first lens 100 as concave, spherical aberration can be reduced, and image quality can be improved.

[0083] In some embodiments of this application, the second lens group includes a third lens 300, a fourth lens 400, a fifth lens 500, and a sixth lens 600 arranged sequentially from the object side to the image side. The object side of the third lens 300 is planar, allowing incident light rays to maintain their original direction and reducing their impact on image quality. Both the object side and image side of the fourth lens 400 are convex, and convex lenses can converge light rays, helping to improve image brightness. The fourth lens 400 is a positive power lens, which can further focus light rays to form a clearer image on the sensor or eyepiece. Both the object side and image side of the fifth lens 500 are convex, and the fifth lens 500 is also a positive power lens. Similar to the fourth lens 400, the fifth lens 500 also has the function of converging and focusing light rays; the combined use of multiple positive power lenses can provide higher focusing capability in the optical system, resulting in a clearer image. The object-side and image-side surfaces of the sixth lens 600 are both concave. The sixth lens 600 is a negative power lens. A negative power lens can diverge light, thereby adjusting the focal length of the optical system and adapting to different observation scenarios and needs by changing the field of view.

[0084] In some embodiments of this application, the fifth lens 500 and the sixth lens 600 are cemented together. Cemented lenses can reduce internal reflections and scattering, thereby reducing light loss, improving beam transmission efficiency, and increasing image brightness. Furthermore, since cementation can compensate for differences in the radius of curvature of the cemented surfaces, the precision requirements of the cemented surfaces can be appropriately reduced. Cemented lenses can also improve the imaging quality of the optical system; because the two lenses are cemented together, their edges overlap, reducing aberrations and improving image sharpness.

[0085] The film layer in the light steering device can be implemented in the following ways:

[0086] First implementation method

[0087] The light steering device 200 includes a first optical mirror 210. The first optical mirror 210 includes a first surface S21, a second surface S22, and a third surface S23.

[0088] A reflective polarizing film layer 250 and a phase retarder 260 are sequentially disposed on the first surface S21 along the optical path direction; a reflective film 270 is disposed on the second surface S22.

[0089] Second implementation method

[0090] The light steering device 200 includes a second optical mirror 220 and a first optical mirror 210 arranged sequentially along the optical axis from the object side to the image side. The first optical mirror 210 includes a first surface S21, a second surface S22, and a third surface S23. The second optical mirror 220 includes a fourth surface S11 away from the first optical mirror 210 and a fifth surface S12 close to the first optical mirror 210.

[0091] The reflective polarizing film layer 250 and the phase retarder 260 are disposed between the fifth surface S12 and the first surface S21, and the reflective polarizing film layer 250 is disposed close to the fifth surface S12; the reflective film 270 is disposed on the second surface S22.

[0092] Third implementation method

[0093] The light steering device 200 includes a second optical mirror 220 and a first optical mirror 210 arranged sequentially along the optical axis from the object side to the image side. The first optical mirror 210 includes a first surface S21, a second surface S22, and a third surface S23. The second optical mirror 220 includes a fourth surface S11 away from the first optical mirror 210 and a fifth surface S12 close to the first optical mirror 210.

[0094] A reflective polarizing film layer 250 is disposed on the fourth surface S11; a phase retarder 260 is disposed between the fifth surface S12 and the first surface S21; and a reflective film 270 is disposed on the second surface S22.

[0095] Fourth implementation method

[0096] like Figure 3 As shown, the light steering device 200 includes a second optical mirror 220, a first optical mirror 210, and a third optical mirror 230 arranged sequentially along the optical axis from the object side to the image side. The first optical mirror 210 includes a first surface S21, a second surface S22, and a third surface S23. The second optical mirror 220 includes a fourth surface S11 away from the first optical mirror 210 and a fifth surface S12 close to the first optical mirror 210. The third optical mirror 230 includes a sixth surface S31 close to the first optical mirror 210 and a seventh surface S32 away from the first optical mirror 210.

[0097] The reflective polarizing film layer 250 and the phase retarder 260 are disposed between the fifth surface S12 and the first surface S21, and the reflective polarizing film layer 250 is disposed close to the fifth surface S12; the reflective film 270 is disposed between the second surface S22 and the sixth surface S31.

[0098] Fifth implementation method

[0099] like Figure 4As shown, the light steering device 200 includes a second optical mirror 220, a first optical mirror 210, and a third optical mirror 230 arranged sequentially along the optical axis from the object side to the image side. The first optical mirror 210 includes a first surface S21, a second surface S22, and a third surface S23. The second optical mirror 220 includes a fourth surface S11 away from the first optical mirror 210 and a fifth surface S12 close to the first optical mirror 210. The third optical mirror 230 includes a sixth surface S31 close to the first optical mirror 210 and a seventh surface S32 away from the first optical mirror 210.

[0100] A reflective polarizing film layer 250 is disposed on the fourth surface S11; a phase retarder 260 is disposed between the fifth surface S12 and the first surface S21; and a reflective film 270 is disposed between the second surface S22 and the sixth surface S31.

[0101] like Figures 5 to 6 As shown, the normal imaging ray path, as ray1, undergoes only one reflection on the first surface S21 of the first optical mirror 210. Figure 5 and Figure 7 As shown, abnormal light rays (mainly light rays incident at a large angle on the fourth surface S11) follow the path of ray2, and undergo two or more reflections on the first surface S21 of the first optical mirror 210, ultimately forming an image on the image plane. The solution provided in this application can effectively eliminate ray2, preventing it from reaching the image plane.

[0102] Specifically, let's take an example where the angle between the transmission axis of the reflective polarizing film layer 250 and the optical axis of the quarter-wave plate is 45 degrees.

[0103] like Figure 5 As shown: Incident light at a normal angle ( Figure 5 middle When unpolarized light passes through the transmissive polarizing film 240, vertically polarized light (P-ray) parallel to the transmission axis of the transmissive polarizing film 240 is produced. Figure 5 In the diagram, "|" represents vertically polarized light. It should be noted that this is not limited to vertically polarized light; it can be polarized light in any other direction, determined by the transmission axis of the transmissive polarizing film 240. When vertically polarized light passes through the reflective polarizing film 250 along its propagation direction, since the transmission axis of the reflective polarizing film 250 is the same as that of the transmissive polarizing film 240 in this embodiment, the polarization direction of the vertically polarized light remains unchanged after passing through the reflective polarizing film 250; it remains vertically polarized light. After the vertically polarized light is incident on the quarter-wave plate, the outgoing light is converted into circularly polarized light. Figure 5 middle (Representing circularly polarized light), after being incident on the second surface S22 and the reflective film 270, the circularly polarized light is completely reflected back to the first surface S21, where it remains circularly polarized. The circularly polarized light continues to propagate and, after being incident on the phase retardation plate 260 (a quarter-wave plate), transforms into horizontally polarized light. Figure 5 (The underscore "_" represents horizontally polarized light). After the horizontally polarized light is incident on the reflective polarizing film layer 250, it is reflected by the reflective polarizing film layer 250 to the quarter-wave plate. At this time, the horizontally polarized light is converted into circularly polarized light after passing through the quarter-wave plate. The circularly polarized light is emitted through the third surface S23 and finally forms an image on the image plane after passing through subsequent lenses.

[0104] like Figure 6 As shown, incident light at a large angle ( Figure 6 middle When unpolarized light passes through the transmissive polarizing film 240, vertically polarized light (P-ray) parallel to the transmission axis of the transmissive polarizing film 240 is produced. Figure 6 In the diagram, "|" represents vertically polarized light. It should be noted that this is not limited to vertically polarized light; it can be polarized light in any other direction, determined by the transmission axis of the transmissive polarizing film 240. When vertically polarized light passes through the reflective polarizing film 250 along its propagation direction, since the transmission axis of the reflective polarizing film 250 is the same as that of the transmissive polarizing film 240 in this embodiment, the polarization direction of the vertically polarized light remains unchanged after passing through the reflective polarizing film 250; it remains vertically polarized light. After the vertically polarized light is incident on the quarter-wave plate, the outgoing light is converted into circularly polarized light. Figure 6 middle (Representing circularly polarized light), after being incident on the second surface S22 and the reflective film 270, the circularly polarized light is completely reflected back to the first surface S21, where it remains circularly polarized. The circularly polarized light continues to propagate and, upon incident on the quarter-wave plate, transforms into horizontally polarized light. Figure 6 (The underscore "_" represents horizontally polarized light). After the horizontally polarized light is incident on the reflective polarizing film 250, it is reflected to the quarter-wave plate. At this point, the horizontally polarized light becomes circularly polarized light after passing through the quarter-wave plate. The circularly polarized light then enters the second surface S22 and the reflective film 270, and is completely reflected back to the first surface S21 by the reflective film 270, where it remains circularly polarized. The circularly polarized light continues to propagate and, after entering the quarter-wave plate, becomes vertically polarized light. The vertically polarized light exits through the reflective polarizing film 250 and continues to propagate, exiting through the transmissive polarizing film. This prevents large-angle incident light from reaching the third surface S23. Figure 6 middle (This indicates that the image cannot pass through), thus preventing the formation of a ghost image on the image plane.

[0105] This application also provides a stereoscopic endoscope, including the aforementioned optical system and an image sensor. The image sensor is positioned on the image side of the optical system and is used to convert light signals transmitted through the optical system into electrical signals. This optical system can provide high-resolution, high-contrast images, and the image sensor's conversion of light signals into electrical signals allows for a clearer display of anatomical structures within the patient's body, improving diagnostic accuracy. The image sensor's location on the image side of the optical system helps reduce the influence of aberrations and improve image quality.

[0106] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the scope of this application. Terms such as “setup” appearing herein can refer to either a component being directly attached to another component or a component being attached to another component via an intermediary. A feature described in one embodiment herein may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0107] This application has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this application to the described embodiments. Those skilled in the art will understand that many more variations and modifications can be made based on the teachings of this application, and all such variations and modifications fall within the scope of protection claimed in this application.

Claims

1. An endoscope optical system, characterized in that, include: The first lens group includes at least one lens with optical power; The second lens group includes at least one lens with optical power, and A light steering device is disposed between the first mirror group and the second mirror group. The light steering device includes a first optical mirror body, which includes a first surface, a second surface and a third surface. An optical film group is disposed on the first surface. The light propagation of the endoscope optical system satisfies: Normal angle incident light rays pass through the first lens group, are incident from the first surface to the second surface, are reflected once by the second surface back to the first surface, are reflected from the first surface to the third surface, and are incident on the second lens group through the third surface to reach the image side for imaging; After passing through the first mirror group, the large-angle incident light rays are incident from the first surface to the second surface, and then reflected at least twice by the second surface back to the first surface. Finally, the large-angle incident light rays are transmitted from the first surface to the object side.

2. The endoscopic optical system according to claim 1, characterized in that, The optical film assembly includes a reflective polarizing film and a phase retarder. The reflective polarizing film and the phase retarder are sequentially disposed on the first surface along the optical path direction. There is an angle θ between the optical axis of the phase retarder and the transmission axis of the reflective polarizing film, where 0 < θ < π / 2.

3. The endoscopic optical system according to claim 2, characterized in that, The angle between the optical axis of the phase retardation film and the transmission axis of the reflective polarizing film is 45°.

4. The endoscopic optical system according to claim 2, characterized in that, The reflective polarizing film transmits light in the same direction as the transmission axis, and reflects or absorbs light perpendicular to the transmission axis.

5. The endoscopic optical system according to claim 2, characterized in that, The phase delay plate is a quarter-wave plate.

6. The endoscopic optical system according to claim 1, characterized in that, The light steering device further includes a reflective film disposed on the second surface.

7. The endoscopic optical system according to claim 6, characterized in that, The reflective film is a reflective film with low transmittance and high reflectance.

8. The endoscopic optical system according to claim 7, characterized in that, The reflective film is a silver reflective film or an aluminum reflective film.

9. The endoscopic optical system according to claim 2, characterized in that, The light steering device further includes a second optical mirror and a third optical mirror, the second optical mirror and the third optical mirror being respectively disposed on the light-inlet side and the light-outlet side of the first optical mirror.

10. The endoscopic optical system according to claim 9, characterized in that, The light-inlet surface of the second optical mirror is provided with a transmissive polarizing film layer, and the transmission axis direction of the transmissive polarizing film layer is the same as that of the reflective polarizing film layer.

11. The endoscopic optical system according to claim 9, characterized in that, A transmissive polarizing film is provided between the light-emitting side surface of the second optical mirror and the reflective polarizing film, and the transmission axis direction of the transmissive polarizing film is the same as that of the reflective polarizing film.

12. The endoscopic optical system according to claim 10 or 11, characterized in that, The light steering device further includes a reflective film, wherein any two of the following components are closely bonded together: the transmissive polarizing film, the second optical mirror, the reflective polarizing film, the phase retarder, the first optical mirror, the reflective film, and the third optical mirror.

13. The endoscopic optical system according to claim 1, characterized in that, The first lens group includes a first lens, which is a negative power lens; the object side of the first lens is a plane and the image side is a concave surface.

14. The endoscopic optical system according to claim 1, characterized in that, The second lens group comprises, arranged sequentially from the object side to the image side: The third lens has a plane on its object-side surface. The fourth lens has both its object-side and image-side surfaces being convex, and it is a positive power lens. The fifth lens has both its object-side and image-side surfaces as convex surfaces, and is a positive power lens. The sixth lens has both its object-side and image-side surfaces concave, and it is a negative power lens.

15. The endoscopic optical system according to claim 14, characterized in that, The fifth lens is cemented together with the sixth lens.

16. A stereoscopic endoscope, characterized in that, include: The optical system according to any one of claims 1-15; and, An image sensor, disposed on the image side of the optical system, is used to convert light signals transmitted through the optical system into electrical signals.

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