A module front end device for an endoscope module

Abstract

This specification provides a module front-end device for an endoscope module. The module front-end device includes an imaging module mounting channel, an instrument channel, an optical fiber mounting channel, and a beam diffuser. The beam diffuser is located at the front end of the optical fiber mounting channel and includes a concave lens. The beam emitted from the optical fiber mounted in the optical fiber mounting channel is refracted by the beam diffuser, increasing its emission angle. By installing the module front-end device of this specification at the front end of a fiber optic illumination endoscope, the fiber emission angle is increased, the illumination range is expanded, and the beam is made more uniform, which is beneficial for the endoscope's imaging module to capture clear images.

Description

[0001] Priority information

[0002] This application claims priority to Chinese application No. 20211608616.3, filed on December 27, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This specification relates to the field of endoscopic devices, and in particular to a module front end device for an endoscope module. Background Technology

[0004] In recent years, endoscopes have been widely used in the medical field and other areas. An endoscope includes an insertion section that can be inserted into the body of the patient, and illumination light can be shone from the tip of the insertion section to observe the illuminated area. Due to its advantages such as low heat generation and small size, fiber optic illumination is widely used as a front-end illumination device in endoscopes.

[0005] Optical fibers are classified into glass fibers and polymer fibers based on their material. Due to the inherent physical properties of the material, glass fibers can achieve a larger beam exit angle, allowing the illumination area to cover the entire field of view of the endoscope imaging module. However, due to complex manufacturing processes and the monopoly of glass formulations, glass fibers are very expensive. Therefore, polymer fibers are widely used in disposable endoscope applications. However, polymer fibers, limited by their material properties, cannot achieve an ideal beam exit angle, making it difficult to cover the entire imaging field of view. Therefore, it is necessary to propose an endoscope module that allows the endoscope to achieve an ideal beam exit angle and improve the coverage of the illumination area even when using polymer fibers as the front-end illumination device. Summary of the Invention

[0006] One embodiment of this specification provides a front-end device for an endoscope module. The front-end device includes: an imaging module mounting channel, an instrument channel, an optical fiber mounting channel, and a beam diffuser; the beam diffuser is disposed at the front end of the optical fiber mounting channel, and includes a concave lens; the beam emitted from the optical fiber installed in the optical fiber mounting channel is refracted by the beam diffuser, resulting in an increased exit angle; the beam diffuser satisfies the following condition: Wherein, EFL is the optical effective focal length of the beam diffuser, and D... f It is the diameter of the optical fiber.

[0007] In some embodiments, the inner surface of the beam diffuser near the optical fiber mounting channel is concave, and the outer surface of the beam diffuser away from the optical fiber mounting channel is planar.

[0008] In some embodiments, a light beam emitted from an optical fiber installed in the optical fiber mounting channel enters the beam diffuser from the concave surface, and after a first refraction on the concave surface, it is directed toward the plane, and after a second refraction on the plane, it exits the beam diffuser; the diffusion angle of the light beam after the first and second refractions is greater than the diffusion angle before each refraction.

[0009] In some embodiments, the concave surface is an aspherical surface; the aspherical surface shape satisfies the following condition:

[0010] Where, r A-max It is the largest effective optical aperture of an aspherical surface; z A-max The maximum effective optical aperture r of an aspherical surface A-max The corresponding elevation.

[0011] In some embodiments, the quadratic curve coefficient k of the surface profile of the aspherical surface is determined at least based on the refractive index of the material of the beam diffuser.

[0012] In some embodiments, after the light beam emitted from the optical fiber installed in the optical fiber mounting channel passes through the beam diffuser, the diameter ratio of the peak illuminance region of the emitted light beam to that of the incident light beam is greater than or equal to 1.5.

[0013] In some embodiments, after the light beam emitted from the optical fiber installed in the optical fiber mounting channel passes through the beam diffuser, the diameter ratio of the half-peak illuminance region of the emitted light beam to that of the incident light beam is greater than or equal to 1.2.

[0014] In some embodiments, after the light beam passes through the light beam diffuser, the diameter of the peak illuminance region and / or the half-peak illuminance region of the emitted light beam is determined at least based on the paraxial spherical radius of curvature of the surface profile of the aspherical surface.

[0015] In some embodiments, the front-end device of the module is manufactured as a single piece.

[0016] In some embodiments, the module front end device is made of a transparent material, including polycarbonate, polystyrene, or polymethyl methacrylate.

[0017] In some embodiments, the fiber optic mounting channel includes a first portion and a second portion, wherein the first portion is connected to the imaging module mounting channel via the second portion.

[0018] In some embodiments, the first portion has a semi-circular cross-section, and the second portion has a square cross-section.

[0019] In some embodiments, the module front-end device includes two optical fiber mounting channels, which are axially symmetrically distributed on both sides of the imaging module mounting channel.

[0020] In some embodiments, the inner surface of the beam diffuser is a smooth surface; the outer surface of the beam diffuser is a diffuse surface. Attached Figure Description

[0021] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0022] Figure 1 These are schematic diagrams illustrating application scenarios of the module front-end device according to some embodiments of this specification;

[0023] Figure 2 This is a three-dimensional structural schematic diagram of the module front-end device shown in some embodiments of this specification;

[0024] Figure 3 This is a front view of the module front-end device shown in some embodiments of this specification;

[0025] Figure 4 This is a cross-sectional view of the beam diffuser shown in some embodiments of this specification;

[0026] Figure 5 This is a schematic diagram of the beam emission of an optical fiber according to some embodiments of this specification;

[0027] Figure 6 This is a schematic diagram of the beam propagation direction when an optical fiber is emitted from a beam diffuser of an aspherical curved surface, according to some embodiments of this specification.

[0028] Figure 7 This is a schematic diagram showing the propagation direction of the optical beam when it exits a conventional plano-concave lens.

[0029] Figure 8 This is a diagram showing the original beam angle state of an optical fiber according to some embodiments of this specification;

[0030] Figure 9 This is a diagram showing the emission state of an optical fiber after beam diffusion following the installation of a beam diffuser, according to some embodiments of this specification.

[0031] Figure 10 This is a simulation diagram of the illuminance distribution of the emitted beam when the fiber optic front end is not equipped with a beam diffuser, according to some embodiments of this specification.

[0032] Figure 11This is a simulation diagram of the illuminance distribution of the emitted beam when a beam diffuser is installed at the fiber optic front end according to some embodiments of this specification.

[0033] Figure 12 This is a schematic diagram of the beam emission of the module front-end device (two sets of optical fibers) according to some embodiments of this specification;

[0034] In the diagram: 10, Endoscope module; 100, Module front-end device; 101, Imaging module installation channel; 102, Fiber optic installation channel; 103, Instrument channel; 104, Beam diffuser; 200, Connecting sleeve; 300, Snake bone; 400, Imaging module; 500, Fiber optic cable. Detailed Implementation

[0035] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0036] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0037] In recent years, endoscopes have been widely used in the medical field and other areas. An endoscope includes an insertion section that can be inserted into the body to be examined, and illumination light can be shone from the tip of the insertion section to observe the illuminated area. In endoscopic illumination technology, especially in the application of disposable endoscopes, polymer optical fibers (i.e., plastic optical fibers) are widely used. However, due to the properties of polymer materials, the beam exit angle of polymer optical fibers is limited (usually less than 70°), making it difficult to cover the entire imaging field of view with illumination. In some embodiments, increasing the number of light sources can improve the illumination field of view to fill the entire field of view. However, this increases the overall outer diameter of the endoscope, which is not conducive to surgical use and can lead to uneven illumination due to overlapping illumination areas, affecting the imaging effect of the endoscope.

[0038] In existing technologies, some endoscopes use plastic optical fibers for illumination and expand the diffusion angle of the light beam emitted from the fiber by adding astigmatic lenses. For example, in the utility model patent application number 202120035628.0, entitled "An Endoscope Illumination Device," the astigmatic lens is a plano-convex lens, with one side convex and the other flat. Since plano-convex lenses converge light, according to the conjugate property of plano-convex lenses, regardless of whether the incident light is incident on the convex or flat surface, the incident light will converge towards the focal point of the plano-convex lens. After the light converges to the focal point, it continues to propagate forward and diverges. According to the imaging principle of convex lenses, the focal point can be considered as forming a real image of the light source, and the light rays directed towards the target can be considered as emanating from this real image. This effect is equivalent to placing the light source at the focal point of the plano-convex lens and then directly using the light source at the focal point to illuminate the target, which is unlikely to truly achieve the effect of diverging or uniformizing the light. In other words, the diffusion angle of the light emitted by the light source did not actually increase, and its uniformity of light did not change.

[0039] This specification provides embodiments of an endoscope module front-end device that can expand the exit angle of the emitted light beam. The front-end device includes a beam diffuser formed as a concave lens. By mounting the front-end device of this specification at the front end of the endoscope module, the optical fiber-guided light beam exits from the front end. After refraction by the beam diffuser within the front-end device, its exit angle (or diffusion angle) increases, thereby improving the coverage of the illumination area. The front-end device is manufactured using a one-piece molding process, resulting in a more compact structure, allowing for a smaller matching endoscope. Simultaneously, one-piece injection molding better ensures product sealing and reduces assembly and material costs.

[0040] Furthermore, when a beam of light transmitted through an optical fiber exits from the fiber end, its central portion is the brightest, gradually darkening towards the edges. When the imaging module takes a picture, during automatic exposure adjustment, it reduces the shooting brightness based on the brightness of the central portion of the illuminated area, resulting in a decrease in shooting brightness across the entire field of view and consequently, a blurry image of the entire illuminated area. The module front-end device provided in some embodiments of this specification can both widen the exit angle of the emitted beam and achieve beam uniformity. In some embodiments, the module front-end device can use a specific optical surface to change the illuminance energy distribution of the beam, thereby achieving beam uniformity.

[0041] Figure 1 These are schematic diagrams illustrating application scenarios of the endoscope module according to some embodiments of this specification; Figure 2 This is a three-dimensional structural schematic diagram of an endoscope module according to some embodiments of this specification; Figure 3This is a front view of an endoscope module shown in some embodiments according to this specification; Figure 4 This is a cross-sectional view of the beam diffuser shown according to some embodiments of this specification. The endoscope module involved in the embodiments of this specification will be described in detail below. It should be noted that the following embodiments are for illustrative purposes only and do not constitute a limitation thereof.

[0042] Endoscope module 10 is primarily used in medical multifunctional endoscopes. In some embodiments, such as Figure 1 As shown, the endoscope module 10 may include a module front-end device 100, a connecting sleeve 200, a snake bone 300, an imaging module 400, and an optical fiber 500. Figure 2 As shown, the module front-end device 100 may include an imaging module mounting channel 101, an instrument channel 103, an optical fiber mounting channel 102, and a beam diffuser 104. In some embodiments, the module front-end device 100 is fixedly connected to the front end of the snake bone 300 of a medical multifunctional endoscope (i.e., the end closest to the human tissue for surgery) via a connecting sleeve 200. The imaging module 400 passes through the tube of the snake bone 300 and is installed in the imaging module mounting channel 101 within the module front-end device 100. The optical fiber 500 passes through the tube of the snake bone 300 and is installed in the optical fiber mounting channel 102 within the module front-end device 100. During surgery, some surgical instruments can pass through the tube of the snake bone 300 and then exit through the instrument channel 103 within the module front-end device 100, directly acting on the human tissue. In use, the optical fiber 500 can emit a beam of light with a certain exit angle (or diffusion angle, such as 60°, 70°, etc.) for illumination, directed towards the human tissue. In some embodiments, a beam diffuser 104 is disposed at the front end of the optical fiber mounting channel 102, and the beam diffuser 104 constitutes a concave lens. The light beam emitted from the optical fiber (e.g., optical fiber 500) installed in the optical fiber mounting channel 102 is refracted by the beam diffuser 104 and directed towards the human tissue. In some embodiments, the beam beam emitted from the optical fiber (e.g., optical fiber 500) has an increased diffusion angle after refraction by the beam diffuser 104.

[0043] In some embodiments, the beam diffuser 104 satisfies the following condition 1:

[0044]

[0045] EFL (Effective Focus Length) is the optically effective focal length of the beam diffuser. The optically effective focal length (EFL) of the beam diffuser can be directly measured using specialized instruments (such as focal length measuring instruments and optical parameter measuring instruments). fIt refers to the diameter of the optical fiber installed in the optical fiber mounting channel 102. When the beam diffuser 104 satisfies condition 1, the beam emitted by the optical fiber (e.g., optical fiber 500) can be refracted by the beam diffuser 104, which can not only increase the diffusion angle, but also improve the illumination uniformity of the beam. For details, please refer to the description in Table 1 below.

[0046] In some embodiments, the optical fiber (such as fiber 500) is made of polymer material. Polymer material optical fiber is an optical transmission fiber (also known as polymer optical fiber) made primarily of polymers, consisting of a high-refractive-index uniform plastic core and a low-refractive-index plastic coating. Polymer material optical fiber has advantages such as light weight, good toughness, and strong light-receiving ability. It is also inexpensive and suitable for use in disposable endoscopes. However, the emission angle of polymer material optical fiber is limited, making it difficult to meet illumination requirements. Therefore, to expand the illumination range of disposable endoscopes, it is necessary to increase the beam diffusion angle.

[0047] In some embodiments, the beam diffuser 104 forms a concave lens. When the light beam emitted from the optical fiber passes through the beam diffuser 104, it is refracted and diverged, increasing the diffusion angle of the light beam exiting the beam diffuser 104. In some embodiments, the beam diffuser 104 can be a plano-concave lens (i.e., one side is concave and the other side is planar). In some embodiments, the inner surface of the beam diffuser 104 near the optical fiber mounting channel 102 is concave, and the outer surface of the beam diffuser 104 away from the optical fiber mounting channel 102 is planar.

[0048] In some embodiments, the inner surface of the beam diffuser 104 near the fiber optic mounting channel 102 may also be a plane, and the outer surface of the beam diffuser 104 away from the fiber optic mounting channel 102 may be a concave surface (not shown in the figure). According to the conjugate property of concave lens imaging, the beam emitted by the fiber optic 500 can increase the beam diffusion angle by entering the beam diffuser 104 from the plane and exiting from the concave surface.

[0049] In some embodiments, the beam diffuser 104 increases the emission angle of the emitted beam by a factor ranging from 1.2 to 2. See also [other embodiments]. Figure 8 The original emission angle of the optical fiber can be 50° to 70°. For example, the original emission angle of the optical fiber can be 60°. In some embodiments, see [link to relevant documentation]. Figure 9After refraction by the beam diffuser 104, the exit angle of the light beam can be between 80° and 130°. Since the luminous flux emitted from the fiber end face is essentially constant, the larger the divergence angle of the emitted beam after refraction and diffusion, the lower the illuminance per unit area. Therefore, a larger exit angle of the refracted beam is not always better. When the field of view of the imaging module is greater than the exit angle of the beam, complete imaging is impossible. When the field of view of the imaging module is less than the exit angle of the beam, the luminous flux of the emitted beam is wasted, resulting in unclear imaging due to low illuminance. Therefore, to achieve the best performance, the exit angle of the refracted beam must match the field of view of the imaging module. For example, when the field of view of the imaging module is 120°, the exit angle of the beam after refraction by the beam diffuser 104 can be 120° for better performance. Of course, if an imaging module with a larger field of view is selected, the exit angle of the refracted beam must be increased accordingly.

[0050] In some embodiments, to achieve a larger diffusion angle for the light beam after passing through the beam diffuser 104, the surface shape of the concave lens can be designed to cause the light beam to undergo two refractions with increased diffusion angles as it passes through the beam diffuser 104. See also Figure 5 , Figure 6 The light beam emitted by the optical fiber 500 enters the beam diffuser 104 from the concave surface, undergoes a first refraction on the concave surface, and then exits the beam diffuser 104 after a second refraction on the plane. The diffusion angle of the light beam emitted by the optical fiber 500 after the first and second refractions is greater than the diffusion angle before each refraction, thus achieving the purpose of having a larger diffusion angle after the light beam emitted by the optical fiber 500 is refracted by the beam diffuser 104.

[0051] In some embodiments, by setting the shape of the incident surface of the beam diffuser 104, the incident angle of the light beam emitted from the optical fiber when it enters the beam diffuser 104 can be controlled. This allows control of the propagation direction of the light beam after refraction by the beam diffuser 104, given the known refractive index of the beam diffuser 104 material, thereby achieving an initial increase in the diffusion angle. See also [link to other embodiments]. Figure 4The incident surface of the beam diffuser 104 can be the inner side of the beam diffuser 104 near the optical fiber mounting channel 102. In some embodiments, the inner side (i.e., concave surface) of the beam diffuser 104 can be an optical curved surface. In this specification, an optical curved surface refers to a curved surface with optical refraction function. In some embodiments, the optical curved surface can be an aspherical surface. In some embodiments, by setting the shape of the exit surface of the beam diffuser 104, the exit direction of the emitted beam from the optical fiber after exiting the beam diffuser 104 can be further controlled, thereby achieving a second increase in the diffusion angle. In some embodiments, the exit surface of the beam diffuser 104 can be the outer side of the beam diffuser 104 away from the optical fiber mounting channel 102. In some embodiments, the outer side of the beam diffuser 104 can be a plane.

[0052] In some embodiments, see Figure 6 The concave surface of the beam diffuser 104 is aspherical. Since an aspherical surface does not have a fixed center, the propagation direction of the beam after passing through the aspherical surface can be controlled by designing its curved surface shape. In some embodiments, by designing the curved surface shape of the aspherical surface, the beam undergoes a first refraction after passing through the aspherical surface, increasing the diffusion angle. When the beam with the increased diffusion angle exits through the plane, it undergoes a second refraction, further increasing the diffusion angle. For specific details on the curved surface shape of the aspherical surface, please refer to other descriptions in this specification; they will not be repeated here.

[0053] In some embodiments, the concave surface of the beam diffuser 104 can also be configured as a sphere, and the beam diffusion angle can be increased by setting the position of the light source (i.e., optical fiber) relative to the sphere. Figure 7 This diagram illustrates the propagation direction of a light beam emitted from a plano-concave lens whose concave surface is a sphere. When the concave surface of the plano-concave lens is spherical, the propagation direction of the light beam after refraction through the concave surface depends on the position of the light source (e.g., an optical fiber) relative to the center of the sphere. When the light source is located at the center of the sphere, the concave surface does not refract the light beam, and the propagation direction of the light beam remains unchanged after passing through the concave surface. However, the divergence angle of the light beam increases after refraction through the exit surface (plane). When the light source is located between the center of the sphere and the concave surface, the divergence angle of the light beam decreases after refraction through the concave surface, and then the divergence angle increases after refraction through the exit surface (plane). Figure 7 This illustrates the propagation path of the light beam when the light source is positioned between the center of the sphere and the concave surface. Figure 7As can be seen, when the light beam enters the concave surface of the plano-concave lens with a spherical concave surface, it undergoes the first refraction. Since the optical fiber enters the plano-concave lens from air (i.e., light travels from a less dense medium to a denser medium, with the angle of refraction smaller than the angle of incidence), the divergence angle of the light beam decreases after the first refraction at the concave surface. When the light beam exits from the plane of the plano-concave lens, it undergoes a second refraction (i.e., light travels from a denser medium to a denser medium, with the angle of refraction greater than the angle of incidence), and the divergence angle of the light beam increases after the second refraction at the plane. In some embodiments, the light source can be positioned on the side of the sphere away from the concave surface (not shown in the figure). In this case, the diffusion angle of the light beam after the first refraction at the concave surface increases, and the second refraction occurs when the light beam exits from the plane of the plano-concave lens, further increasing the diffusion angle. Figure 6 and Figure 7 It can be seen that by setting the concave surface as an aspherical surface and by setting the curved surface shape of the aspherical surface, the propagation direction of the beam after passing through the beam diffuser 104 can be controlled more accurately, and a larger beam diffusion angle can be achieved. At the same time, the optical fiber can also be set closer to the beam diffuser 104, which is beneficial to reduce the volume of the module front-end device 100.

[0054] In some embodiments, optimizing the concave surface of the beam diffuser 104 can further improve illumination uniformity. Illumination uniformity refers to the trend of illuminance variation with the diameter of the light spot formed when a beam illuminates a target; a slower trend indicates improved illumination uniformity. For more information on achieving illumination uniformity by configuring the beam diffuser 104, please refer to this specification. Figures 10-11 The relevant descriptions will not be repeated here.

[0055] In some embodiments, the aspherical surface profile can be determined based on the material physical properties of the module front-end device 100, including refractive index, transmittance, haze, etc. In some embodiments, when the transmittance and haze of the material are constant, the aspherical surface profile is mainly determined based on the refractive index of the material of the module front-end device 100. Since the refractive index of the material is constant after the module front-end device 100 selects a material, the incident angle when the beam enters the aspherical surface can be determined based on the refractive index of the material, the required exit angle, and the original divergence angle of the fiber optic beam. This incident angle is the angle between the incident beam and the normal to the incident surface at the incident point. After the incident angle of the beam at any point on the surface profile is determined, the normal direction of that point on the surface profile can be determined, thereby determining the curvature change of the surface profile at that point. Using the same method, the curvature changes of multiple points on the aspherical surface profile are calculated, and by fitting multiple points, the surface profile of this aspherical surface can be obtained.

[0056] In some embodiments, the surface profile of an aspherical surface can be represented as a function of the aspherical surface's elevation and the diameter corresponding to that elevation. In some embodiments, the formula for the surface profile of an aspherical surface is:

[0057]

[0058] Where c is the reciprocal of the radius of curvature R of the paraxial spherical surface (i.e., c = 1 / R); k is the quadratic curve coefficient; r is the diameter of the aspherical surface; α1, α2...α8 are aspherical coefficients; and z is the sag of the aspherical surface. See Appendix. Figure 4 In this context, the origin O can represent the center point of the aspherical surface, and point A can represent any point on the aspherical surface. Then, in the diagram z... A r is the elevation of point A. A It is the aperture of the aspherical surface at point A. In some embodiments, the maximum value of the aperture r of the aspherical surface is slightly larger than the radius of the optical fiber by 0.02 to 0.1 mm.

[0059] In some embodiments, the surface profile of an aspherical surface can be represented by a function relating the aspherical surface's elevation to the diameter corresponding to that elevation. In some embodiments, the aspherical coefficients α1, α2...α8 are all equal to 0, therefore the formula for the surface profile of an aspherical surface can be:

[0060]

[0061] In some embodiments, the aspherical surface shape can be designed by using the quadratic curve coefficient k in Formula 1 or Formula 2. In some embodiments, the quadratic curve coefficient k is determined at least based on the refractive index of the material of the module front-end device 100. In some embodiments, the value of the quadratic curve coefficient k can be -2.8 to -3.5. This value of the quadratic curve coefficient k can be calculated and simulated based on the required increase in the emission angle and the selected material. For example, if the material of the module front-end device 100 is polycarbonate (PC), and the emission angle of the beam after passing through the beam diffuser 104 is 120°, then the quadratic curve coefficient k of the aspherical surface is -2.8 to -3.5, preferably -3.17.

[0062] In some embodiments, to further improve the uniformity of the beam by the beam diffuser 104, the paraxial spherical radius of curvature R of the aspherical surface can be set within a suitable range. In some embodiments, after the optical fiber beam passes through the beam diffuser, the diameter range of the illumination spot formed by the emitted beam under the same illuminance is determined at least based on the paraxial spherical radius of curvature R of the aspherical surface. The paraxial spherical radius of curvature R refers to the spherical radius within an infinitesimally small region of the optical axis. In some embodiments, the value of the paraxial spherical radius of curvature R is determined based on different optical fiber materials, optical fiber diameter, original optical fiber emission angle, distance between the plano-concave lens and the illuminated target, effective illumination area, etc.

[0063] The quadratic curve coefficient k mainly determines the size of the optical fiber diffusion angle after the light emitted from the optical fiber passes through the plano-concave lens, and the paraxial spherical radius of curvature R mainly determines the brightness uniformity of the emitted light after passing through the plano-concave lens. In some embodiments, the quadratic curve coefficient k and the paraxial spherical radius of curvature R can be determined simultaneously by calculation and simulation. In some embodiments, the process of determining the quadratic curve coefficient k and the paraxial spherical radius of curvature R may include the following steps: (1) Establishing an equivalent light source model of the optical fiber based on the spectrum of the optical fiber installed in the optical fiber mounting channel 102. (2) Establishing a lens model based on the refractive index of the material of the beam diffuser 104, wherein the lens model is a plano-concave lens model, with the concave surface of the plano-concave lens facing the equivalent light source and the plane facing the illuminated object. (3) Determining the objective function based on the target diffusion angle and target illumination uniformity of the beam after passing through the plano-concave lens, and determining the quadratic curve coefficient k and the paraxial spherical radius of curvature R based on the objective function. It should be noted that the above steps do not need to be strictly performed in order; for example, the order of steps (1) and (2) can be interchanged.

[0064] In some embodiments, the surface shape of the non-spherical surface satisfies the following condition 2:

[0065]

[0066] Where, r A-max This refers to the maximum effective optical aperture of the aspherical surface. In this embodiment, the maximum effective optical aperture of the aspherical surface is the aperture of the end of the aspherical surface closest to the optical fiber installed in the optical fiber mounting channel 102. This maximum effective optical aperture is numerically equal to the aperture of the optical fiber installed in the optical fiber mounting channel 102, i.e., numerically r A-max =D f z A-max The maximum effective optical aperture r of an aspherical surface A-max The corresponding elevation.

[0067] In some embodiments, when the aspherical curved surface of the beam diffuser 104 satisfies conditions 1 and 2, it not only ensures that the illumination range of the beam emitted after passing through the beam diffuser 104 is expanded, but also ensures that the beam illumination is uniform. See Table 1 below for details.

[0068] Figure 10 Simulation diagram of the illuminance distribution of the emitted beam when the fiber front end is not equipped with a beam diffuser, according to some embodiments of this specification; Figure 11 This is a simulation diagram of the illuminance distribution of the emitted beam when a beam diffuser is installed at the fiber optic front end according to some embodiments of this specification. In the diagram, the vertical axis represents illuminance in lux, and the horizontal axis represents the radius of the illumination field of view in millimeters. In some embodiments, the degree of beam diffusion can be measured by observing the diameter of the effective illumination area of ​​the spot formed by the beam emitted from the beam diffuser 104 in the target area. The effective illumination area refers to the effective range that the beam emitted from the fiber optic cable can illuminate after passing through the plano-concave lens. This effective illumination area is related to the emission angle of the beam after refraction by the beam diffuser and the distance between the plano-concave lens and the illuminated target. In some embodiments, the distance between the illuminated target (e.g., a human organ that needs to be illuminated during surgery) and the plano-concave lens is a constant value. In some embodiments, the fiber optic cable is a polymer fiber, and the distance between the illuminated target and the plano-concave lens is 7 mm. See [link to relevant documentation]. Figure 10 When the illuminance of the light emitted from the original optical fiber is 100 lux, the diameter of the effective illumination area *c* is 7.6 mm. When the illuminance is below 100 lux, the area can be considered an ineffective illumination range due to the extremely low light intensity. See also... Figure 11 The beam from the optical fiber increases in diffusion angle after refraction by the beam diffuser 104, resulting in an effective illumination area c' with a diameter of 20.5 mm at an illuminance of 100 lux. Therefore, the design of the beam diffuser 104 effectively increases the beam diffusion angle after refraction, thereby increasing the effective illumination range and ensuring it exceeds the field of view of the imaging module.

[0069] In some embodiments, the illumination uniformity of the light beam can be measured by observing the diameter of the peak illuminance region and / or half-peak illuminance region of the light spot formed by the light beam emitted from the beam diffuser 104 in the target area. If the diameter of the peak illuminance region and / or half-peak illuminance region of the light beam emitted from the beam diffuser 104 is larger than that of the light beam at the time of incidence, then the illumination uniformity of the light beam after passing through the beam diffuser 104 is improved. The peak illuminance region refers to the illumination area where the beam illuminance is greater than or equal to 95% of the peak beam illuminance. See [link to relevant documentation]. Figure 10 a in and Figure 11The "a'" in the text refers to the half-peak illuminance region, which is the illuminance area of ​​the beam that is greater than or equal to 50% of the peak illuminance. (See also: [link to relevant documentation]). Figure 10 b and Figure 11 b' in the middle.

[0070] In some embodiments, after the light beam emitted from the optical fiber installed in the optical fiber mounting channel 102 passes through the beam diffuser 104, the diameter ratio of the peak illuminance region of the emitted light beam to that of the incident light beam is greater than or equal to 1.5.

[0071] In some embodiments, after the light beam emitted from the optical fiber installed in the optical fiber mounting channel 102 passes through the beam diffuser 104, the diameter ratio of the half-peak illuminance region of the emitted light beam to that of the incident light beam is greater than or equal to 1.2.

[0072] contrast Figure 10 and Figure 11 ,exist Figure 10 In the case of an optical fiber without a beam diffuser, the illuminance value at the peak of the illuminance curve is very high. The peak region is concentrated in the peak illuminance area of ​​the illumination range, resulting in a very high illuminance value in the central region of the field of view (reaching 50,000 lux). Therefore, this centrally concentrated point is extremely bright. When the imaging module takes a picture, during automatic exposure adjustment, it reduces the shooting brightness based on the brightness of the central part of the illumination area, thus reducing the shooting brightness across the entire field of view and resulting in unclear imaging of the entire illumination area. After the beam emitted from the optical fiber passes through the beam diffuser 104, the diameter ratio of the peak illuminance region of the emitted beam to the incident beam is greater than or equal to 1.5, meaning the central region of the field of view is significantly larger, and the overall illuminance value is reduced (approximately 22,000 lux). In some embodiments, compared to... Figure 10 and Figure 11 ,exist Figure 11 In the (beam diffuser 104 mounted in front of the optical fiber), the diameter 'a' of the peak illuminance region of the original beam can be 1.4 mm, and the diameter 'a' of the peak illuminance region of the beam after refraction by the beam diffuser 104 can be 2.6 mm. After the beam emitted from the optical fiber passes through the beam diffuser 104, the ratio of the diameter of the peak illuminance region of the emitted beam to the diameter of the incident beam is 1.857. Therefore, when the imaging module images human tissue, the brightness of a relatively large area in the center of the field of view is relatively uniform, and the illuminance is lower than the peak illuminance when the beam diffuser 104 is not set. Therefore, when the imaging module takes a picture, the overall shooting brightness does not need to be significantly reduced.

[0073] In some embodiments, after the light beam emitted from the optical fiber passes through the beam diffuser 104, the diameter ratio of the half-peak illuminance region of the emitted beam to the diameter of the incident beam is greater than or equal to 1.1. See also: [link to embodiments]. Figure 11 The diameter b of the half-peak illuminance region of the original beam can be 5 mm, and the diameter b' of the half-peak illuminance region of the beam after refraction by the beam diffuser 104 can be 8.4 mm. Therefore, after the beam emitted by the optical fiber passes through the beam diffuser 104, the ratio of the diameter of the half-peak illuminance region of the emitted beam to the diameter of the incident beam is 1.68.

[0074] The diameters a' of the peak illuminance region and b' of the half-peak illuminance region mentioned in the above embodiments can be used to characterize the uniformity of the light emitted from the beam diffuser 104. On the other hand, see... Figure 11 After the beam diffuser 104 is set, the illumination brightness within the same radius of the field of view changes less with the radius of the field of view. Therefore, it is beneficial to reduce the brightness difference between non-peak and peak areas, and further improve the imaging effect. Thus, by setting the beam diffuser 104, a uniform beam effect can be achieved, enabling the imaging module to capture clear images.

[0075] In some embodiments, the module front-end device 100 (i.e., the entire module front-end device including the beam diffuser 104) is made of a single material and manufactured using a one-piece molding process. Since the module front-end device is small in size, using a separate production and bonding technique would be more costly. Therefore, the module front-end device 100 described in this specification is manufactured using a one-piece molding process based on material characteristics to reduce production costs and increase output. The one-piece molded module front-end device eliminates the need for embedding the beam diffuser, requires no bonding, and has no gaps, completely eliminating the potential safety hazards associated with disinfection and avoiding the risk of the beam diffuser detaching.

[0076] In some embodiments, the module front-end device 100 may be made of a transparent material. Preferably, the module front-end device 100 is made of a highly transparent material. In some embodiments, the highly transparent material may be one in which the energy loss of the light beam is less than 5% when the light beam passes through it. In some embodiments, the module front-end device 100 may be made of polycarbonate (PC). Polycarbonate is a colorless, transparent, amorphous thermoplastic material with good impact resistance, high transparency, and good processability.

[0077] In some embodiments, the module front-end device 100 may also be made of polystyrene (PS), polymethyl methacrylate (PMMA), etc. Polystyrene is a thermoplastic resin with good flowability, processability, easy coloring, and dimensional stability. It can be processed into various parts using injection molding, extrusion, blow molding, foaming, thermoforming, bonding, coating, welding, machining, printing, etc., and is particularly suitable for injection molding. Polymethyl methacrylate is a high-molecular polymer, also known as acrylic or plexiglass. It has advantages such as high transparency, low price, and ease of machining, and is a commonly used glass substitute.

[0078] Compared to a split structure, using cost-effective materials and a one-piece molding process to produce the module front-end device 100 results in a more compact structure, allowing for a smaller structure in the matching endoscope module 10. Simultaneously, one-piece injection molding better ensures product sealing and reduces assembly and material costs. For example, the module front-end device 100 described in this specification is made of polycarbonate (PC) through one-piece injection molding, and the cost, calculated based on mold opening fees, material costs, and labor costs, is approximately RMB 0.03–0.1 per unit. Currently, module front-end devices on the market generally require the embedding of a glass beam diffuser (commonly known as a "glass astigmatism lens"). For example, the 0.8mm diameter glass astigmatism lens produced by Hangzhou Haoke Optoelectronic Instrument Co., Ltd. has a unit price of approximately RMB 100–160 per unit based on a minimum order quantity of 3000 units. The small size and high precision of the glass astigmatic lens necessitate a matching high-precision module front-end device. The glass astigmatic lens also requires bonding and assembly onto the module front-end device; higher precision increases assembly difficulty and labor costs. Furthermore, due to the high cost of the glass astigmatic lens, it requires repeated sterilization for reuse during endoscope use. The module front-end device described in this specification reduces the cost by 1000 to 3000 times compared to the glass astigmatic lens, with production costs low enough to be used as a disposable medical device, enabling the module front-end device 100 described in this specification to be widely applied in the medical field.

[0079] In some embodiments, see Figure 2The fiber optic mounting channel 102 includes a first part 121 and a second part 122. The first part 121 is connected to the imaging module mounting channel 101 through the second part 122, so that the fiber optic mounting channel 102 and the imaging module mounting channel 101 form a connected cavity. This structural design is to improve the service life of the injection mold used to produce the front-end device of the module. Because if the cross-section of the fiber optic mounting channel 102 is circular (matching the outer diameter of the fiber optic cable 500 installed inside it), then the fiber optic mounting channel 102 is a cylindrical elongated cavity. For example, if the diameter of the selected fiber optic cable 500 can be 0.5 mm, then the fiber optic mounting channel 102 can be a cylindrical elongated cavity with an inner diameter slightly larger than 0.5 mm. When the integrated injection molding module front-end device 100 in the above embodiments is produced, a matching long steel rod needs to be installed in the optical fiber mounting channel 102 to occupy this space (i.e., cavity filler) so that the molten plastic cannot enter this cavity. Only after the final product cools and solidifies can a cylindrical long cavity be formed as the optical fiber mounting channel 102. When a 0.5mm diameter long steel rod is used as the cavity filler for the optical fiber mounting channel 102, because the steel rod is very hard and very small, the molten plastic liquid injected into the mold cavity at a very high speed during injection molding will have a significant impact on the steel rod, easily leading to damage. Damage to the steel rod during injection molding requires stopping production and replacing it, which severely reduces production efficiency.

[0080] When selecting cavity filler of the same material (e.g., steel), the strength of the material itself cannot be changed. Therefore, in the above embodiments, the strength of the cavity filler is increased by increasing its volume. Thus, in some embodiments, the non-functional area around the fiber optic mounting channel 102 of the module front-end device 100 can be structurally optimized to increase the volume of the fiber optic mounting channel 102 and connect it to the imaging module mounting channel 101.

[0081] In some embodiments, see Figure 2 The first part 121 has a semi-circular cross-section, and the second part 122 has a square cross-section. This structural design allows for the use of an integrated cavity filler in the fiber optic mounting channel 102 and the imaging module mounting channel 101 during injection molding (i.e., the cavity filler in the fiber optic mounting channel 102 and the cavity filler in the imaging module mounting channel 101 are designed as a single piece of steel). This effectively increases the strength of the cavity filler, significantly improves the service life of the injection mold, and thus improves the efficiency of injection molding production of the module front-end device 100.

[0082] In some embodiments, there may be one fiber optic mounting channel 102 for mounting a group of optical fibers 500. In some embodiments, there may also be multiple fiber optic mounting channels 102, allowing multiple groups of optical fibers 500 to be mounted simultaneously. In some embodiments, the number of fiber optic mounting channels 102 may be the same as the number of optical fibers 500. In some embodiments, the module front-end device 100 includes multiple fiber optic mounting channels 102 distributed around the imaging module mounting channel 101. Using multiple groups of optical fibers 500 can increase the illumination area. The arrangement of the imaging module mounting channel 101, instrument channel 103, and fiber optic mounting channel 102 can be designed according to the specific needs of different surgeries, and is not limited here.

[0083] In some embodiments, see Figures 2-3 The module front-end device 100 may include two fiber optic mounting channels 102, which can mount two sets of optical fibers 500. The two fiber optic mounting channels 102 are symmetrically arranged on both sides of the imaging module mounting channel 101. For example, the two fiber optic mounting channels 102 can be symmetrically arranged on both sides of the imaging module mounting channel 101. Because the overall structure of the module front-end device 100 is relatively small, and channels such as the imaging module mounting channel 101 and / or instrument channel 103 need to be provided, multiple fiber optic mounting channels 102 can only be arranged within the limited space of the module front-end device 100. Furthermore, it is necessary to ensure imaging quality (i.e., not only to ensure a sufficiently large illumination range but also to ensure beam uniformity). Therefore, symmetrically arranging two fiber optic mounting channels 102 on both sides of the imaging module mounting channel 101 is a superior layout. See also... Figure 12The two fiber optic mounting channels 102 of the module front-end device 100 are symmetrically arranged on both sides of the imaging module mounting channel 101. The imaging module is mounted within the imaging module mounting channel 101, and the camera focus of the imaging module is located on the axis of the imaging module mounting channel 101. Two sets of optical fibers are mounted within the two fiber optic mounting channels 102. When the light beams emitted from the two sets of optical fibers exit the module front-end device 100, there is a beam overlap area in front of the imaging module mounting channel 101, which can increase the illumination intensity of the overlap area and effectively improve image clarity. In some embodiments, the module front-end device 100 may also have only one fiber optic mounting channel 102, but the center of the illumination area of ​​the beam emitted from one set of optical fibers will have a positional deviation from the camera focus of the imaging module (i.e., the camera focus will be in a darker position within the illumination area), resulting in unclear imaging. In some embodiments, the module front-end device 100 may also have four fiber optic mounting channels 102 evenly distributed around the imaging module mounting channel 101. Although the illumination area of ​​the beams emitted from the four sets of fibers may ensure a sufficiently large illumination range and sufficient brightness at the camera focus of the imaging module, the four fiber optic mounting channels 102 would increase the overall structural volume of the module front-end device 100. In the medical field, the smaller the size of the module front-end device 100, the better. Therefore, the design of two fiber optic mounting channels 102 on the module front-end device 100 is a preferred solution.

[0084] In some embodiments, the inner surface of the beam diffuser 104 is a smooth surface. In some embodiments, the outer surface of the beam diffuser 104 is a diffuse surface. The terms "smooth surface" and "diffuse surface" are relative concepts. A diffuse surface refers to a plane that reflects light irregularly (e.g., in different directions), while a smooth surface refers to a plane that reflects light regularly (e.g., in the same direction). The inner surface is designed as a relatively flat and smooth surface to reduce light loss due to reflection when the beam reaches the outer surface, ensuring the beam refraction effect. The outer surface is designed as a diffuse surface, which can be achieved by, for example, using a frosted or matte surface. Its rough surface causes the beam to diffuse as it exits, thereby changing the propagation direction of a small portion of the beam and achieving uniform light distribution. For example, Figure 12 The beams emitted by the two sets of optical fibers will form an overlapping area in front of the imaging module mounting channel 101. There is a possibility that the brightness of the overlapping area will be too high. The design of the diffuse surface can further improve the illumination uniformity of the emitted beam.

[0085] In some embodiments, the beam diffuser 104 may not have a diffuser surface; instead, it may diffuse the beam using the curved surface characteristics of the aspherical surface described in the above embodiments to achieve uniform light. By not providing a diffuser surface, the luminous flux can be preserved as much as possible, ensuring sufficient illumination when the light is off.

[0086] The optical diffuser 104 described in this specification, along with the experimental parameters (Table 1) for using optical fiber, are as follows:

[0087]

[0088] Table 1 above provides, as examples only, five sets of experimental parameters (Experiment 1, Experiment 2, Experiment 3, Experiment 4, and Experiment 5) for beam diffusers of some embodiments of this specification. Additionally, Table 1 also provides a set of experimental parameters for beam diffusers that do not satisfy condition 2 (Experiment 6), and a set of experimental parameters for beam diffusers that do not satisfy condition 1 (Experiment 7). In Table 1, the material, fiber aperture Df, ... The distance between the illuminated target and the optical diffuser are optical parameters of the beam diffuser in this embodiment. The values ​​of the emission angle and the diameter of the effective illumination area can be used to explain the effect of expanding the beam illumination range after the optical fiber passes through the beam diffuser. The ratio of the diameter of the peak illuminance area of ​​the beam at the emission point to the diameter of the beam at the emission point to the diameter of the half-peak illuminance area of ​​the beam at the emission point to the diameter ... The experimental parameters of Experiment 6 show that when the optical diffuser in Experiment 6... When condition 2 is not met, both the exit angle and the diameter of the effective illumination area are small, indicating a poor beam illumination amplification effect. Simultaneously, the ratios of the diameters of the peak illuminance region at the exit and entrance points and the half-peak illuminance region at the exit and entrance points are also small, indicating poor beam illumination uniformity. The experimental parameters of Experiment 7 show that when the optical diffusion section of Experiment 7... When condition 1 is not satisfied, although the emission angle and the diameter of the effective illumination area are good, indicating a good beam illumination expansion effect, the ratio of the diameter of the peak illuminance region of the beam at emission to the diameter of the beam at half-peak illuminance region at emission to the diameter ...

[0089] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0090] Furthermore, this specification uses specific terms to describe embodiments thereof. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0091] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0092] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0093] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A front-end device for an endoscope module, characterized in that, include: Imaging module mounting channel, instrument channel, fiber optic mounting channel, and beam diffuser; The beam diffuser is disposed at the front end of the optical fiber mounting channel, and the beam diffuser constitutes a concave lens. The beam emitted by the optical fiber installed in the optical fiber installation channel is refracted by the beam diffuser, and the emission angle increases. The beam diffuser satisfies the following condition: Wherein, EFL is the optical effective focal length of the beam diffuser, and D... f It is the diameter of the optical fiber.

2. The module front-end device as described in claim 1, characterized in that, The inner surface of the beam diffuser near the optical fiber mounting channel is concave, while the outer surface of the beam diffuser away from the optical fiber mounting channel is planar.

3. The module front-end device as described in claim 2, characterized in that, A light beam emitted from an optical fiber installed in the optical fiber mounting channel enters the beam diffuser from the concave surface, and after a first refraction on the concave surface, it is directed toward the plane, and after a second refraction on the plane, it exits the beam diffuser; the diffusion angle of the light beam after the first and second refractions is greater than the diffusion angle before each refraction.

4. The module front-end device as described in claim 2, characterized in that, The concave surface is an aspherical surface; the aspherical surface shape satisfies the following condition: Where, r A-max It is the largest effective optical aperture of an aspherical surface; z A-max The maximum effective optical aperture r of an aspherical surface A-max The corresponding elevation.

5. The module front-end device as described in claim 4, characterized in that, The quadratic curve coefficient k of the surface profile of the aspherical surface is determined at least based on the refractive index of the material of the beam diffuser.

6. The module front-end device as described in claim 5, characterized in that, After the light beam emitted from the optical fiber installed in the optical fiber installation channel passes through the light beam diffuser, the diameter ratio of the peak illuminance region of the emitted light beam to that of the incident light beam is greater than or equal to 1.

5.

7. The module front-end device as described in claim 6, characterized in that, After the light beam emitted from the optical fiber installed in the optical fiber installation channel passes through the light beam diffuser, the diameter ratio of the half-peak illuminance region of the emitted light beam to that of the incident light beam is greater than or equal to 1.

2.

8. The module front-end device as described in claim 7, characterized in that, After the beam passes through the beam diffuser, the diameter of the peak illuminance region and / or the half-peak illuminance region of the emitted beam is determined at least based on the paraxial spherical radius of curvature R of the aspherical surface profile.

9. The module front-end device as described in claim 1, characterized in that, The front-end device of the module is manufactured using a one-piece molding process.

10. The module front-end device as described in claim 9, characterized in that, The front-end device of the module is made of a transparent material, including polycarbonate, polystyrene or polymethyl methacrylate.

11. The module front-end device as described in claim 9, characterized in that, The fiber optic mounting channel includes a first part and a second part, wherein the first part is connected to the imaging module mounting channel through the second part.

12. The module front-end device as described in claim 11, characterized in that, The first part has a semi-circular cross-section, and the second part has a square cross-section.

13. The module front-end device as described in claim 9, characterized in that, The module front-end device includes two optical fiber mounting channels, which are symmetrically distributed on both sides of the imaging module mounting channel.

14. The module front end device of the endoscope module as described in any one of claims 1-13, characterized in that: The inner surface of the beam diffuser is a smooth surface; the outer surface of the beam diffuser is a diffuse surface.

Images