An endoscope lens and endoscope

Abstract

The application relates to the technical field of endoscopes, in particular to an endoscope lens and an endoscope, a plurality of lenses and an infrared cut-off filter are sequentially arranged from an object side to an image side, the infrared cut-off filter is arranged at a set region between the plurality of lenses, the set region is a region where, after light rays of the object side pass through at least one lens, the incident angle of the light rays is less than or equal to 30 DEG; and the offset amount of the central wavelength of the infrared cut-off filter is less than 25 nm when the incident angle of the light rays of the medical surgical laser is 30 DEG. The infrared cut-off filter is arranged between the plurality of lenses in the endoscope lens, the angle of the light rays of the object side is compressed to within 30 DEG after passing through at least one lens, so that the incident angle of the light rays entering the lens is all less than or equal to 30 DEG. The image color is uniform, and the medical surgical laser light rays can be filtered out, so that the color deviation and the ripple problem of the image are solved.

Description

Technical Field

[0001] This application relates to the field of endoscope technology, specifically to an endoscope lens and an endoscope. Background Technology

[0002] In the field of clinical medicine, lasers, with their excellent monochromaticity, collimation, and high energy density, have made significant progress in biomedical applications, especially in minimally invasive surgery. Lasers treat airway lesions through non-contact thermal coagulation and hemostatic vaporization effects.

[0003] Laser surgery requires endoscopic imaging and tracking throughout the procedure. Since medical surgical lasers operate in the infrared band, if the endoscope lacks an infrared cutoff filter, no infrared light enters the lens when laser operation is not required, resulting in a normal, color-accurate image. However, during laser operation, infrared light enters the lens, interfering with the endoscope's image sensor and causing a reddish tint to the image. Furthermore, the laser pulse signal can create multiple ripples in the image, resulting in jittery horizontal lines and affecting image quality.

[0004] Therefore, in related technologies, an infrared cutoff filter is often added to the lens of the endoscope. Typically, an infrared cutoff filter has high transmittance across the entire visible light spectrum and high reflectivity in the infrared spectrum, with an incident angle ranging from 0° to 30° and a center wavelength shift of approximately 30nm (see [reference]). Figure 1 (The center wavelength offset and transmittance are shown).

[0005] In some laser surgery scenarios, such as the removal of airway tumors, bronchoscopy is required for continuous tracking and imaging. Typically, the field of view of the bronchoscopy is greater than 90 degrees, and the incident angle of the image sensor is large at all four sides. The received red light will be reduced due to the cutoff wavelength shifting towards shorter wavelengths. As a result, the red component of the image is reduced at the edges. Since the image sensor has an automatic white balance function, it will increase the overall red component of the image. The final result is that the center of the image is red and the edges are green, resulting in uneven color.

[0006] Therefore, improving the color uniformity of endoscopic images during laser surgery has become an urgent technical problem to be solved. Utility Model Content

[0007] This application provides an endoscope lens and an endoscope to solve the technical problem mentioned in the background art of how to improve the color uniformity of images captured by the endoscope during laser surgery.

[0008] According to a first aspect, this application provides an endoscope lens, in which a plurality of lenses and an infrared cut-off filter are sequentially arranged from the object side to the image side. The infrared cut-off filter is disposed in a predetermined region between the plurality of lenses. The predetermined region is a region where the incident angle of light from the object side after passing through at least one lens is less than or equal to 30°. When the incident angle of the medical surgical laser light is 30°, the offset of the center wavelength of the infrared cut-off filter is less than 25nm.

[0009] Optionally, the transmittance of the infrared cut-off filter is less than 1% after the light from the medical surgical laser is incident on the endoscope lens at any incident angle.

[0010] Optionally, the substrate includes a substrate and an asymmetric alternating stack of membranes disposed on the substrate.

[0011] Optionally, the plurality of lenses include: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially from the object side to the image side, wherein the first lens is a negative power lens, the second lens is a positive power lens, the third lens is a positive power lens, the fourth lens is a positive power lens, and the fifth lens is a negative power lens.

[0012] Optionally, the infrared cutoff filter is disposed between the second lens and the third lens.

[0013] Optionally, the total optical power of the first lens and the second lens is negative;

[0014] The total optical power of the third, fourth, and fifth lenses is positive.

[0015] Optionally, the object-side surface of the first lens is planar, and the image-side surface is concave.

[0016] The object-side surface of the second lens is convex, and the image-side surface is concave.

[0017] The object-side surface of the third lens is flat, and the image-side surface is convex.

[0018] The fourth lens is a biconvex lens;

[0019] The object-side surface of the fifth lens is concave, while the image-side surface is planar.

[0020] Optionally, the absolute value of the radius of curvature of the image side of the second lens is greater than the radius of curvature of the object side.

[0021] Optionally, the center wavelength of the medical surgical laser is 1064 nm.

[0022] According to a second aspect, this application provides an endoscope including an endoscope lens as described in any of the first aspects above.

[0023] This application has at least the following beneficial effects:

[0024] An infrared cutoff filter is added to the endoscope lens to block the light from the surgical laser. To prevent the received red light from being reduced due to the cutoff wavelength shifting towards shorter wavelengths, thus preventing uneven image color caused by a decrease in red components around the edges of the image, the infrared cutoff filter's center wavelength shift is less than 25nm when the incident angle of the surgical laser light is 30°. Simultaneously, to ensure that all light within the endoscope's field of view is within the controlled range, the infrared cutoff filter is placed between multiple lenses in the endoscope lens. Light from the object side is compressed to an angle of less than 30° after passing through at least one lens, ensuring that the incident angle of the light entering the lens at the infrared cutoff filter F is less than or equal to 30°. Furthermore, it reduces the center wavelength shift of the medical surgical laser light incident angle from 0° to 30°, increases the consistency of the light transmission curve under each incident angle, solves the problems of red center, green periphery and uneven color in the image, and can filter out the medical surgical laser light so that it cannot be incident on the image sensor. Therefore, it can solve the problems of red image caused by laser wavelength and ripple caused by laser pulse signal.

[0025] Furthermore, the infrared cutoff filter maintains a transmittance of less than 1% for surgical laser light incident on the endoscope lens at any angle. It effectively cuts off the target center wavelength using an asymmetric alternating film stack. For 1064nm wavelength optical fibers, after passing through at least one lens, the transmittance to the infrared cutoff filter is reduced to below 1% at an incident angle of less than 30°. Light in the 1064nm band cannot enter the image sensor at large angles from the edge of the endoscope lens, thus avoiding the reddish tint and ripples caused by laser pulse signals in the image, improving image clarity.

[0026] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram showing the transmittance curves of medical surgical lasers through an endoscope lens at different incident angles in the prior art.

[0029] Figure 2 This is a schematic diagram of the structure of an endoscope lens provided in an embodiment of this application;

[0030] Figure 3 This is a schematic diagram showing the transmittance curves of the endoscope lens provided in this application for medical surgical lasers at different incident angles. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0032] As described in the background section, laser surgery requires endoscopic monitoring throughout the procedure. Taking neodymium lasers as an example, neodymium lasers primarily treat airway lesions through non-contact thermal coagulation and hemostatic vaporization. Their deep-penetrating 1064nm near-infrared wavelength allows them to be used for applications such as airway obstruction by malignant tumors. Neodymium lasers can rapidly vaporize and remove tumor tissue within the airway, immediately relieving large airway obstruction. Neodymium lasers can also be used for precise hemostasis. During the surgery, observation is conducted through an endoscope equipped with an infrared cutoff filter. Ordinary infrared cutoff filters have high transmittance across the entire visible light spectrum and high reflectance in the infrared spectrum. The incident angle ranges from 0° to 30°, with a center wavelength shift of approximately 30nm, and transmittance significantly increases near the 1064nm wavelength.

[0033] The field of view of an endoscope lens is usually greater than 90°. The incident angle of the light incident on the image sensor is large. The received red light will be reduced because the cutoff wavelength shifts to a shorter wavelength. The red component around the edge of the image is reduced. Since the photosensitive chip has an automatic white balance function, it will increase the red component of the overall image. The end result is that the center of the image is red and the edges are green, resulting in uneven color.

[0034] Furthermore, when the incident angle of light is greater than 30°, the infrared cutoff effect of ordinary infrared cutoff filters in the 1000nm to 1100nm wavelength range decreases significantly, and the transmittance in this wavelength range can reach more than 5%.

[0035] When the incident angle of light on an image sensor is large, the transmittance of the neodymium laser in the 1064nm band increases rapidly, while the cutoff effect decreases significantly. At higher neodymium laser power, light in the 1064nm band can enter the chip at large angles from the edges. Near-infrared light in the 1064nm band, after entering the lens, interferes with the image sensor, causing the image to appear reddish. Simultaneously, due to the influence of the neodymium laser pulse signal, multiple beams of light are formed in the image, affecting image clarity. Some existing technologies use infrared cutoff filters on a blue glass substrate. Because these filters absorb infrared light, the center wavelength shift is approximately 2nm from 0° to 30°, resulting in good consistency in transmittance curves across different incident angles, thus avoiding color inhomogeneity. However, the transmittance of visible light on a blue glass substrate is poor, and the transmittance of long-wavelength red visible light is significantly reduced. Therefore, the overall brightness will be significantly reduced, the image brightness will be greatly lost, and because the red component is reduced, the image will be bluish overall. Since the observed object is blood vessels in the body, the amount of blood vessel information will be reduced after the white balance algorithm correction.

[0036] Based on this, embodiments of this application provide an endoscope lens, such as... Figure 2 As shown, the lens includes multiple lenses arranged sequentially from the object side to the image side, and an infrared cut-off filter F. The infrared cut-off filter F is disposed in a predetermined region between the multiple lenses. This predetermined region is where the incident angle of light rays from the object side, after passing through at least one lens, is less than or equal to 30°. Within this predetermined region, all light rays within the endoscope's field of view, after passing through at least one lens, have an incident angle of less than or equal to 30° within this predetermined region. Furthermore, when the incident angle of the medical surgical laser light is 30°, the center wavelength shift of the infrared cut-off filter F is less than 25 nm.

[0037] In this embodiment, an infrared cutoff filter F is added to the endoscope lens to block the light from the surgical laser. To prevent uneven image color caused by the reduction of red components around the edges of the image due to the cutoff wavelength shifting towards shorter wavelengths, the infrared cutoff filter F has a center wavelength shift of less than 25nm when the incident angle of the surgical laser light is 30°. Simultaneously, to ensure that all light within the endoscope's field of view is within the controllable range, the infrared cutoff filter F is positioned between multiple lenses in the endoscope lens. After passing through at least one lens, the angle of light from the object side is compressed to within 30°, ensuring that the incident angle of the light entering the lens at the infrared cutoff filter F is less than or equal to 30°. Furthermore, it reduces the center wavelength shift of the medical surgical laser light incident angle from 0° to 30°, increases the consistency of the light transmission curve under each incident angle, solves the problems of red center, green periphery and uneven color in the image, and can filter out the medical surgical laser light so that it cannot be incident on the image sensor, thus solving the problems of color cast and ripples in the image.

[0038] In one embodiment, in order to ensure that the center wavelength shift of the infrared cut-off filter F is less than 25 nm when the incident angle of the medical surgical laser is less than 30°, the substrate of the infrared cut-off filter F can be a high refractive index substrate, and an asymmetric alternating film stack structure is deposited on the substrate. This ensures high transmittance of visible light while controlling the shift of the center wavelength towards shorter wavelengths and ensuring infrared light.

[0039] In one embodiment, the transmittance of the infrared cut-off filter F is less than 1% after the light from the surgical laser enters the endoscope lens at any incident angle. When the surgical laser light enters the endoscope lens at any angle and passes through at least one lens, reaching the infrared cut-off filter F, the transmittance of the infrared cut-off filter to the laser light is reduced to below 1% when the incident angle of the infrared cut-off filter is less than 30°.

[0040] For example, taking a neodymium laser as an example, its center wavelength is 1064nm, and its stopband center wavelength is also 1064nm. In this embodiment, the substrate can be a sapphire substrate. By depositing an asymmetric alternating film stack on the sapphire substrate, high transmittance of visible light from 400nm to 650nm is ensured while suppressing 1064nm infrared light, reducing the offset of incident infrared light towards shorter wavelengths to 20nm. The transmittance curves at different incident angles show good consistency. The sapphire substrate, with its high refractive index and reduced internal refraction angle, exhibits almost no absorption of visible light, thus avoiding color inhomogeneity while ensuring image brightness and uniformity of each color component, solving the problems of reddish centers and greenish edges in images, and overall color inhomogeneity. Figure 3The transmittance curves shown are from different angles.

[0041] In an optional embodiment, a silver nanolayer can also be inserted between the substrate and the film layer, utilizing the weak absorption of the metal at 1064 nm and the synergy of the asymmetric alternating film stack to maintain the total transmittance at <1%. In this embodiment, as... Figure 3 As shown, the infrared cut-off filter F reduces the transmittance of the 1064nm band to below 1% for incident angles less than 30°. Light in the 1064nm band is less likely to enter the lens at large angles from the edges (e.g., the angle at which light is incident at the maximum field of view when the field of view of an endoscope lens is 120° to 140°). After passing through the lens and the infrared cut-off filter F, it enters the image sensor, preventing the reddish tint caused by the laser wavelength and the wavy lines caused by the laser pulse signal in the image, thus improving image clarity.

[0042] In one embodiment, such as Figure 2 As shown, the multiple lenses in the endoscope lens may include a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 arranged sequentially from the object side to the image side, wherein the first lens L1 is a negative power lens, the second lens L2 is a positive power lens, the third lens L3 is a positive power lens, the fourth lens L4 is a positive power lens, and the fifth lens L5 is a negative power lens.

[0043] The infrared cutoff filter F is positioned between the second lens L2 and the third lens L3.

[0044] In this embodiment, the first lens L1 can be a lens with a flat object-side surface and a concave image-side surface, for widening the viewing angle and initially compressing the light angle. The second lens L2 can be a lens with a convex object-side surface and a concave image-side surface, which, through the first lens L1, converges the diverging light rays, creating a low incident angle environment for the infrared cutoff filter F. The third lens L3 can be a lens with a flat object-side surface and a convex image-side surface. The fourth lens L4 can be a biconvex lens, and the fifth lens L5 can be a lens with a concave object-side surface and a flat image-side surface.

[0045] In this design, the object-side surface of the second lens L2 matches the curvature direction of the image-side surface of the first lens L1. The first lens L1 converges diverging light rays, while the absolute value of the radius of curvature of the image-side surface of the second lens L2 is greater than that of the object-side surface. This enhances the converging ability of edge light rays and reduces astigmatism. Therefore, through the design of L1 and L2, it is ensured that light rays incident at any angle outside the lens reach the F filter at an angle no greater than 30 degrees.

[0046] In one embodiment, the radius of curvature of the image side of the first lens L1 is smaller than the radius of curvature of the object side of the second lens L2, and the radius of curvature transitions smoothly between the first lens L1 and the second lens L2 to avoid abrupt changes in light at the interface that could lead to total internal reflection.

[0047] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0048] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0049] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0050] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

Claims

1. An endoscope lens, characterized in that, Multiple lenses and an infrared cut-off filter are sequentially arranged from the object side to the image side. The infrared cut-off filter is located in a predetermined area between the multiple lenses. The predetermined area is the region where the incident angle of light rays from the object side is less than or equal to 30° after passing through at least one lens. The infrared cutoff filter has a center wavelength offset of less than 25nm when the incident angle of the medical surgical laser is 30°.

2. The endoscope lens of claim 1, wherein, The transmittance of the infrared cut-off filter is less than 1% when the light from the medical surgical laser is incident on the endoscope lens at any incident angle.

3. The endoscope lens as described in claim 1, characterized in that, The invention includes a substrate and an asymmetric alternating membrane stack disposed on the substrate.

4. The endoscope lens of claim 1, wherein, Multiple lenses include: A first lens, a second lens, a third lens, a fourth lens, and a fifth lens are sequentially arranged from the object side to the image side, wherein the first lens is a negative power lens, the second lens is a positive power lens, the third lens is a positive power lens, the fourth lens is a positive power lens, and the fifth lens is a negative power lens.

5. The endoscope lens of claim 4, wherein, The infrared cutoff filter is disposed between the second lens and the third lens.

6. The endoscope lens as described in claim 5, characterized in that, The total optical power of the first lens and the second lens is negative; The total optical power of the third, fourth, and fifth lenses is positive.

7. The endoscope lens as described in claim 4, characterized in that, The object-side surface of the first lens is flat, and the image-side surface is concave. The object-side surface of the second lens is convex, and the image-side surface is concave. The object-side surface of the third lens is flat, and the image-side surface is convex. The fourth lens is a biconvex lens; The object-side surface of the fifth lens is concave, while the image-side surface is planar.

8. The endoscope lens of claim 7, wherein, The absolute value of the radius of curvature of the image side of the second lens is greater than the radius of curvature of the object side.

9. The endoscope lens of claim 1, wherein, The central wavelength of the medical surgical laser is 1064nm.

10. An endoscope characterized by comprising: Includes the endoscope lens as described in any one of claims 1-9.

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