An illumination system for a medical endoscope

Abstract

The application relates to endoscope technology and discloses an illumination system of a medical endoscope, which comprises a white light source, a light guide rod, a first collimating lens, a second collimating lens, a first dichroic mirror, a first focusing lens, a second focusing lens, a filter, a first laser source, a first beam expander, a third collimating lens, a second dichroic mirror, a second laser source, a second beam expander and a fourth collimating lens; the first collimating lens, the second collimating lens, the third collimating lens, the fourth collimating lens, the first focusing lens, the second focusing lens, the first beam expander and the second beam expander are all spherical lenses. The application also discloses a medical endoscope. The application realizes the illumination system of the medical endoscope which meets the illumination of white light and two kinds of lasers at the same time by transmitting and reflecting the white light and the two kinds of lasers respectively, and makes the illumination system capable of being prepared by using spherical lenses, so that the manufacturing cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of endoscopes, in particular to a medical endoscope illumination system and a medical endoscope. BACKGROUND

[0002] Endoscope technology plays a vital role in modern medicine, allowing doctors to examine and treat internal organs of patients without major surgery. The illumination system is an important part of the endoscope system, providing the necessary illumination for the endoscope to ensure that the doctor can clearly see the lesion area.

[0003] Traditional endoscope illumination systems are usually designed with aspherical glass lenses to reduce optical aberrations and improve imaging quality. However, the processing technology of aspherical lenses is complex, especially when using a mold pressing process, the cost is relatively high. This limits the widespread application of endoscope illumination systems, especially in cost-sensitive medical environments. And the existing medical endoscope illumination system is generally white light + single laser illumination, which is difficult to meet the dual fluorescence requirement of using dual laser illumination (the second fluorescence is generally used for non-invasive ureter visualization to prevent damage to the ureter during surgery).

[0004] The above content is only used to assist in understanding the technical solutions of the present application, and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0005] The main purpose of the present application is to provide a medical endoscope illumination system and a medical endoscope, which realizes the illumination system of a medical endoscope that meets white light and two different laser illuminations by transmitting and reflecting the white light and the two different lasers respectively, and at the same time makes the illumination system can be prepared using spherical lenses to reduce manufacturing costs.

[0006] To achieve the above purpose, the present application provides a medical endoscope illumination system, which comprises: a first collimating lens, a second collimating lens, a first dichroic mirror, a first focusing lens, a second focusing lens and a filter arranged in sequence from the white light source to the light guide rod; and the transmission surface of the first dichroic mirror is at a 45° angle towards the second collimating lens, and the reflection surface of the first dichroic mirror is at a 45° angle towards the first focusing lens.

[0007] In the direction which is at a 45° angle with the reflection surface of the first dichroic mirror and is perpendicular to the direction from the white light source to the light guide rod, a first expansion lens, a third collimating lens and a second dichroic mirror are further arranged in sequence between the first laser source and the reflection surface of the first dichroic mirror; wherein the second dichroic mirror is parallel to the first dichroic mirror, and the reflection surface of the second dichroic mirror is towards the first dichroic mirror, and the transmission surface of the second dichroic mirror is towards the third collimating lens.

[0008] A second expansion lens and a fourth collimating lens are sequentially arranged between the second laser source and the mirror in a direction perpendicular to the direction from the white light source to the light guide rod; wherein the mirror is parallel to the second dichroic mirror and faces the reflecting surface of the second dichroic mirror.

[0009] The first collimating lens, the second collimating lens, the third collimating lens, the fourth collimating lens, the first focusing lens, the second focusing lens, the first expansion lens and the second expansion lens are all spherical lenses; and the first laser source and the second laser source emit laser beams of different wavelengths.

[0010] To achieve the above object, the application further provides a medical endoscope comprising the illumination system of the medical endoscope.

[0011] The illumination system of the medical endoscope and the medical endoscope provided by the application use spherical lenses in the illumination system, which are relatively simple in processing technology, thus greatly reducing the manufacturing cost of the illumination system; the illumination system can provide not only white light illumination but also two different laser illuminations, thus meeting the dual fluorescence imaging requirement of the medical endoscope; meanwhile, the illumination system can provide a uniform light field by reasonably arranging the positions and angles of the lenses and optimizing the distribution of the light field; and even if spherical lenses are used, the illumination system can still achieve high optical transmission efficiency through precise optical design and adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 Fig. 1 is a schematic diagram of the architecture of the illumination system of the medical endoscope in an embodiment of the application.

[0013] REFERENCE SIGNS

[0014] 1, white light source; 2, first collimating lens; 3, second collimating lens; 4, first dichroic mirror; 5, second laser source; 6, second expansion lens; 7, fourth collimating lens; 8, mirror; 9, first laser source; 10, first expansion lens; 11, third collimating lens; 12, second dichroic mirror; 13, first focusing lens; 14, second focusing lens; 15, filter; 16, light guide rod.

[0015] The object, functional characteristics and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0016] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary, and are intended to explain the present application, and cannot be understood as limiting the present application, all other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0017] In addition, if the description involving "first", "second" and the like in the present application is only for the purpose of description (such as for distinguishing the same or similar features), and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that the technical solutions can be realized by those of ordinary skill in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection required by the present application.

[0018] Reference Figure 1 In an embodiment, an illumination system of a medical endoscope is provided, which comprises: a first collimating lens 2, a second collimating lens 3, a first dichroic mirror 4, a first focusing lens 13, a second focusing lens 14 and a filter 15 arranged in the direction from a white light source 1 to a light guide rod 16 in turn, and the transmission surface of the first dichroic mirror 4 is at an angle of 45° to the second collimating lens 3, and the reflection surface of the first dichroic mirror 4 is at an angle of 45° to the first focusing lens 13;

[0019] In the direction which is at an angle of 45° to the reflection surface of the first dichroic mirror 4 and is perpendicular to the direction from the white light source 1 to the light guide rod 16, a first expansion lens 10, a third collimating lens 11 and a second dichroic mirror 12 are further arranged in turn between the first laser source 9 and the reflection surface of the first dichroic mirror 4; wherein the second dichroic mirror 12 is parallel to the first dichroic mirror 4, and the reflection surface of the second dichroic mirror 12 is towards the first dichroic mirror 4, and the transmission surface of the second dichroic mirror 12 is towards the third collimating lens 11;

[0020] In the direction which is perpendicular to the direction from the white light source 1 to the light guide rod 16, a second expansion lens 6 and a fourth collimating lens 7 are further arranged in turn between the second laser source 5 and the reflecting mirror 8; wherein the reflecting mirror 8 is parallel to the second dichroic mirror 12 and is towards the reflection surface of the second dichroic mirror 12;

[0021] The first collimating lens 2, the second collimating lens 3, the third collimating lens 11, the fourth collimating lens 7, the first focusing lens 13, the second focusing lens 14, the first beam expander 10 and the second beam expander 6 are all spherical lenses; the first laser source 9 and the second laser source 5 emit laser beams of different wavelengths.

[0022] In the embodiment, the white light source 1 is used to provide white light and emit the white light to the first collimating lens 2. The white light source 1 can be a 400-700nm white light LED, that is, the white light can be visible light of 400-700nm.

[0023] The first collimating lens 2 is a lens with positive focal power, which is used to converge the white light emitted by the white light source 1 to the second collimating lens 3.

[0024] The second collimating lens 3 is a lens with positive focal power, which is used to further converge the white light converged by the first collimating lens 2 and make the white light incident to the transmission surface of the first dichroic mirror 4 at an angle of 45°.

[0025] Optionally, the first dichroic mirror 4 is a flat glass with a focal power of 0; the transmission surface of the first dichroic mirror 4 is coated with a transmission film for transmitting the white light; and the reflection surface of the first dichroic mirror 4 is coated with a reflection film for reflecting the laser.

[0026] The transmission surface of the first dichroic mirror 4 is used to transmit the white light further converged by the second collimating lens 3 to the first focusing lens 13.

[0027] The first laser source 9 is used to provide laser and emit the laser to the first beam expander 10. The first laser source 9 can be a 660nm semiconductor laser, that is, the laser can be a near-infrared laser of 660nm.

[0028] The first beam expander 10 is a lens with negative focal power, which is used to perform divergence, beam expansion and uniform light processing on the laser emitted by the first laser source 9 and scatter the processed laser to the third collimating lens 11.

[0029] The third collimating lens 11 is a lens with positive focal power, which is used to converge the scattered laser into collimated parallel laser and make the parallel laser incident to the transmission surface of the second dichroic mirror 12 at an angle of 45°.

[0030] The second dichroic mirror 12 is a flat glass with a focal power of 0; the transmission surface of the second dichroic mirror 12 is coated with a transmission film for transmitting the laser emitted by the first laser source 9; the reflection surface of the second dichroic mirror 12 is coated with a reflection film for reflecting the laser emitted by the second laser source 5; and the transmission surface of the second dichroic mirror 12 is used to transmit the straightened laser of the third collimating lens 11 to the reflection surface of the first dichroic mirror 4.

[0031] The second laser source 5 is used to provide laser and emit laser to the second beam expander 6. The second laser source 5 is different from the first laser source 9 in wavelength. The second laser source 5 can be a 785nm semiconductor laser, i.e. the laser can be a 785nm near-infrared laser.

[0032] The second beam expander 6 is a lens same as the first beam expander 10, and the second beam expander 6 is used to perform divergence beam expansion and uniform light processing on the laser emitted by the second laser source 5, and scatter the processed laser to the fourth collimating lens 7.

[0033] The fourth collimating lens 7 is a lens same as the third collimating lens 11, and the fourth collimating lens 7 is used to converge the diffused laser into collimated parallel laser, and make the parallel laser incident to the mirror 8 at an angle of 45°.

[0034] The mirror 8 is used to reflect the laser straightened by the fourth collimating lens 7 to the reflecting surface of the second dichroic mirror 12 at an angle of 90°, so as to reflect the laser to the reflecting surface of the first dichroic mirror 4 at an angle of 90° through the reflecting surface of the second dichroic mirror 12.

[0035] The reflecting surface of the first dichroic mirror 4 is used to reflect the laser reflected and transmitted by the second dichroic mirror 12 to the first focusing lens 13 at an angle of 90°.

[0036] The first focusing lens 13 is a lens with positive focal power, used to focus the incident white light and laser to the second focusing lens 14.

[0038] The second focusing lens 14 is a lens with positive focal power, used to further focus the incident white light and laser. Between the second focusing lens 14 and the light focusing point of the second focusing lens 14, a filter 15 is further arranged.

[0039] The filter 15 is used to selectively filter the light focused by the second focusing lens 14. For the white light, the filter 15 is used to transmit the white light and cut off the laser; for the laser, the filter 15 is used to transmit the laser and cut off the white light. Two kinds of filters 15 can be provided, one of which is used to transmit the white light and cut off the laser (such as transmitting the white light of 400~650nm and cutting off the laser of 650~800nm), and the other of which is used to transmit the laser and cut off the white light (such as cutting off the white light of 400~650nm and transmitting the laser of 650~800nm). The two kinds of filters 15 can be switched back and forth by a motor according to the specific filtering requirement.

[0040] The light guide rod 16 has a focal power of 0 and is arranged at the light focusing point of the second focusing lens 14, which is used to separate the light guide beam and the light focusing point to avoid the high temperature generated by focusing from burning and damaging the light guide beam, and can also play a role in uniform light.

[0040] Optionally, when the lighting system adopts white light illumination, the white light emitted by the white light source 1 passes through the first collimating lens 2, the second collimating lens 3, the first dichroic mirror 4, the first focusing lens 13, the second focusing lens 14, and the optical filter 15 in sequence, and is finally coupled into the light guide rod 16, so that the light guide beam is connected to the light emitting end surface of the light guide rod 16, and the light can be coupled into the light guide beam.

[0041] Since the divergence angle of the white light source 1 is generally large (up to 120°), the white light rays must be collimated first to reduce the divergence angle and the spot size, so as to facilitate the coupling of the light into the light guide beam. The first collimating lens 2 and the second collimating lens 3 form a white light collimating lens group, which mainly collimates the large-angle light rays of the white light into parallel light. The white light collimating lens group is designed as a spherical glass lens, which can be manufactured by traditional optical cold processing technology, and the cost is relatively low.

[0042] The collimated parallel light of the white light passes through the first dichroic mirror 4 for light splitting. The first dichroic mirror 4 transmits white light and reflects laser light (it can transmit white light of 400-650 nm and reflect laser light of 650-800 nm). Therefore, when the white light passes through the transmission surface of the first dichroic mirror 4, it can pass through the transmission surface to reach the first focusing lens 13. Since the first dichroic mirror 4 is a flat plate and does not provide optical power, it does not change the propagation direction of the light, and the white light remains collimated after passing through the first dichroic mirror 4.

[0043] The first focusing lens 13 and the second focusing lens 14 form a focusing lens group, which mainly focuses and couples the collimated light passing through the first dichroic mirror 4 into the light guide rod 16. Here, it needs to be considered that the light guide beam has an NA value and an optical aperture. Therefore, the image-side NA of the converging light of the focusing lens group must be less than or equal to the NA value of the light guide beam, and the focusing spot must be less than or equal to the optical aperture of the light guide beam, so that the light can be coupled into the light guide beam to the maximum extent, and the loss of optical energy can be reduced. The focusing lens group is designed as a spherical glass lens, which can be manufactured by traditional optical cold processing technology, and the cost is relatively low. There is an optical filter 15 between the focusing lens group and the light guide rod 16, and the optical filter 15 is switched to transmit white light and cut off laser light at this time.

[0044] The white light passes through the focusing lens group and the filter 15, and is coupled into the light guide rod 16 at a certain angle and spot size. Since the energy and temperature at the focal point are very high, if the light entry end surface of the light guide beam is directly placed at the focal point of the light, the extremely high temperature can burn the light guide beam, so a light guide rod 16 must be added at the focal point, and the light guide beam can be placed at the light exit surface of the light guide rod 16, thereby avoiding the focal point, protecting the light guide beam, and prolonging the service life of the light guide beam. Moreover, the light rays make total reflection in the light guide rod 16, and a certain light uniformity effect can be achieved. Therefore, the material of the light guide rod 16 can be an optical glass material with good light transmission and high temperature resistance.

[0045] In this way, the entire white light path is a straight-through coaxial optical system, and the propagation path of the light rays is all transparent. The completely transparent optical system can maximize the reduction of light energy loss and improve the optical transmission coupling efficiency of the white light.

[0046] Optionally, when the illumination system is illuminated by the first laser source 9, the near-infrared laser (marked as the first laser) emitted by the first laser source 9 passes through the first beam expander lens 10, the third collimating lens 11, and the transmission surface of the second dichroic mirror 12 in turn, is reflected by 90° on the reflection surface of the first dichroic mirror 4 into the focusing lens group, and after focusing, passes through the filter 15 and is coupled into the light guide rod 16. The light guide beam is connected to the light exit end surface of the light guide rod 16, and the light rays can be coupled into the light guide beam.

[0047] Since the divergence angle of the first laser is relatively small, and it is a Gaussian beam distribution, the energy is basically concentrated in a small angle range. Therefore, the first laser must be subjected to divergence beam expansion and light uniformity processing. The first beam expander lens 10 can expand the divergence angle of the first laser and make the light field distribution of the first laser uniform. Moreover, the first beam expander lens 10 is designed as a spherical glass lens, which can adopt a traditional optical cold processing technology, and the cost is relatively low. After divergence beam expansion, the first laser also needs to be collimated, and the light rays can be coupled into the focusing lens group. The third collimating lens 11 can collimate the divergent light rays into parallel light, and the spot size of the collimated light is consistent with that of the white light, which is more conducive to focusing and coupling into the light guide rod 16. Moreover, the third collimating lens 11 is designed as a spherical glass lens, which can adopt a traditional optical cold processing technology, and the cost is relatively low.

[0048] The first laser is shaped into collimated parallel light by the third collimating lens 11, and then transmitted to the reflecting surface of the first dichroic mirror 4 through the transmitting surface of the second dichroic mirror 12; wherein the second dichroic mirror 12 is used for transmitting the laser emitted by the first laser source 9 and reflecting the laser emitted by the second laser source 5 (such as transmitting 660 nm laser and reflecting 785 nm laser). The first laser transmitted through the transmitting surface of the second dichroic mirror 12 is reflected on the reflecting surface of the first dichroic mirror 4, and the angle between the reflecting surface of the first dichroic mirror 4 and the incident first laser is 45°. The first dichroic mirror 4 can reflect the first laser into the focusing lens group. Like the white light, the first laser converges through the focusing lens group, and then passes through the optical filter 15 (at this time, the optical filter 15 is switched to be able to transmit laser and cut off near white light), and finally is coupled into the light guide rod 16 at a certain angle and spot size. The light guide beam is connected to the light emitting end surface of the light guide rod 16, and the light can be coupled into the light guide beam.

[0049] Optionally, when the illumination system is illuminated by the second laser source 5, the near-infrared laser (marked as the second laser) emitted by the second laser source 5 is sequentially transmitted through the second beam expander 6 and the fourth collimating lens 7, and then is incident to the mirror 8 at an angle of 45°. The mirror 8 reflects the second laser by 90° to the reflecting surface of the second dichroic mirror 12, and then the reflecting surface of the second dichroic mirror 12 reflects the second laser by 90° to the reflecting surface of the first dichroic mirror 4. The second laser is reflected by 90° into the focusing lens group on the reflecting surface of the first dichroic mirror 4, and then passes through the optical filter 15 and is coupled into the light guide rod 16 after focusing. The light guide beam is connected to the light emitting end surface of the light guide rod 16, and the light can be coupled into the light guide beam.

[0050] Since the divergence angle of the second laser is relatively small, and it is a Gaussian beam distribution, the energy is basically concentrated in a small angle range. Therefore, the second laser must be first diverged and expanded to uniformize the light field distribution. The second beam expander 6 can expand the divergence angle of the second laser and uniformize the light field distribution of the laser. The second beam expander 6 is designed as a spherical glass lens, which can adopt a traditional optical cold processing technology and has a relatively low cost. After the divergence and expansion of the second laser, the light needs to be collimated, and then the subsequent light can be coupled into the focusing lens group. The fourth collimating lens 7 can collimate the divergent light into parallel light, and the size of the collimated light spot is consistent with the white light, which is more conducive to the subsequent focusing and coupling of the laser into the light guide rod 16. The fourth collimating lens 7 is designed as a spherical glass lens, which can adopt a traditional optical cold processing technology and has a relatively low cost.

[0051] The second laser is shaped into collimated parallel light by the fourth collimating lens 7, is reflected by the mirror 8 to the reflecting surface of the second dichroic mirror 12, is reflected by the reflecting surface of the second dichroic mirror 12 to the reflecting surface of the first dichroic mirror 4, and the angle between the reflecting surface of the first dichroic mirror 4 and the incident second laser is 45°. The first dichroic mirror 4 can reflect the second laser into the focusing lens group. Like the first laser, the second laser is converged by the focusing lens group, passes through the filter 15, and is finally coupled into the light guide rod 16 at a certain angle and spot size. The light guide beam is connected to the light emitting end surface of the light guide rod 16, and the light can be coupled into the light guide beam.

[0052] In fact, the second laser light path is an off-axis three-mirror optical system, the mirror 8 and the two dichroic mirrors are arranged in parallel in space, and the layout is also reasonable. The whole system is compactly arranged, which can reduce the overall size of the optical system, and can compress the overall size of the illumination system while meeting the transmission of the second laser light path.

[0053] In this way, the white light and the two kinds of lasers are integrated into one illumination system through a clever spatial layout, and finally the light of the three light paths can be emitted from the light guide rod 16 and the light guide beam, realizing a white light & laser three-light-path composite illumination system, and making the overall size of the illumination system smaller, forming a compact layout structure, and having high space utilization.

[0054] The first collimating lens 2, the second collimating lens 3, the third collimating lens 11, the fourth collimating lens 7, the first focusing lens 13, the second focusing lens 14, the first expansion lens 10 and the second expansion lens 6 are all designed as spherical lenses (such as spherical glass lenses), and the lens processing method is a traditional optical cold processing technology, which is much lower in cost than the non-spherical glass molding process. Moreover, the lens material can be glass material, which is easy to obtain. The second expansion lens 6 and the first expansion lens 10 are the same and can be shared; the third collimating lens 11 and the fourth collimating lens 7 are the same and can be shared, greatly saving the cost; only six sets of cold processing jigs are needed for the whole illumination system, which is relatively low in cost. While realizing low cost, the illumination system can also realize extremely high optical transmission efficiency and excellent light field distribution uniformity.

[0055] In an embodiment, the lenses in the illumination system are all spherical lenses with relatively simple processing technology, which greatly reduces the manufacturing cost of the illumination system; and the illumination system can not only provide white light illumination, but also provide two different laser illuminations, thereby meeting the dual-fluorescence imaging requirement of the medical endoscope; meanwhile, by reasonably arranging the lens positions and angles and optimizing the distribution of the light field, the illumination system can provide a uniform light field; and even if spherical lenses are used, the illumination system can still achieve high optical transmission efficiency through precise optical design and adjustment.

[0056] Since the illumination system has good optical performance such as uniform light field and high optical transmission efficiency, in the application of the medical endoscope, the illumination system can meet the low-cost and dual-fluorescence imaging requirement, improve the image quality and reduce the spot effect, and meet the requirements of high brightness and high illumination uniformity of the medical endoscope.

[0057] In an embodiment, on the basis of the above embodiment, the first collimating lens 2 is a meniscus lens, and the concave surface faces the white light source 1 and the convex surface faces the second collimating lens 3.

[0058] In this embodiment, the first collimating lens 2 is a meniscus lens with positive optical power.

[0059] Optionally, the central thickness of the first collimating lens 2 is 13.9 mm, the concave surface has a curvature radius of R32.2 mm, the convex surface has a curvature radius of R18.2 mm, and the diameter is Ø35 mm.

[0060] Since it is necessary to receive as much as possible the large-angle light coupled from the white light source 1, the concave surface is arranged close to the side of the white light source 1, and the convex surface is arranged away from the side of the white light source 1. In the white light collimating lens group, the first collimating lens 2 needs to bear most of the optical power to converge the large-angle light of the white light, and therefore, a heavy lanthanum flint glass H-ZLAF92 with high refractive index can be selected as the optical glass material, so that the curvature of the lens can be designed to be smaller, which is convenient for processing and production, and the two optical surfaces of the lens are both spherical surfaces, which can be processed by a traditional optical cold processing technology with relatively low cost.

[0061] Both optical surfaces can be coated with an AR film (anti-reflection film) with a reflectivity of less than 0.5%.

[0062] In an embodiment, on the basis of the above embodiment, the second collimating lens 3 is a plano-convex lens, and the plane faces the first collimating lens 2 and the convex surface faces the transmission surface of the first dichroic mirror 4.

[0063] In this embodiment, the second collimating lens 3 is a plano-convex lens with positive optical power.

[0064] Optionally, the central thickness of the second collimating lens 3 is 10 mm, the convex curvature radius is R33.3 mm, and the diameter is Ø43 mm.

[0065] The second collimating lens 3 can shape the white light passing through the first collimating lens 2 into collimated parallel light. Since the first collimating lens 2 has already borne most of the optical power, the optical power of the second collimating lens 3 can be relatively small, so that a low refractive index and high transmittance optical glass material H-K9L can be selected. In order to save production and processing costs, a positive power plano-convex lens can be designed, the plane of the plano-convex lens is close to the side of the first collimating lens 2, and the convex surface is away from the side of the first collimating lens 2. Moreover, the convex surface is designed as a spherical surface, and the traditional optical cold processing technology is adopted, which has a relatively low cost.

[0066] Both optical surfaces can be coated with AR film, and the reflectivity is less than 0.5%.

[0067] Optionally, the white light collimating lens group composed of the first collimating lens 2 and the second collimating lens 3 needs to minimize the diameter of the collimated light spot, so that the angle of the edge light after focusing is smaller, so that the light is more easily coupled into the light guide rod 16. Therefore, the collimated light spot diameter can be designed to be less than Ø38 mm.

[0068] In an embodiment, on the basis of the above-mentioned embodiment, the first expansion lens 10 is a plano-concave lens, and the plane faces the first laser source 9 and the concave surface faces the third collimating lens 11.

[0069] In this embodiment, the first expansion lens 10 is a plano-concave lens with negative optical power.

[0070] Optionally, the central thickness of the first expansion lens 10 is 6 mm, the concave curvature radius is R17.272 mm, and the diameter is Ø24 mm.

[0071] In order to save costs, the first expansion lens 10 can be designed as a plano-concave lens, the plane of the lens is close to the side of the first laser source 9, and the concave surface is away from the side of the first laser source 9. The main effect of the concave surface is to diverge and expand the light.

[0072] In order to save costs and improve light transmittance, the first expansion lens 10 can select a high transmittance optical glass material H-K9L. After the laser light passes through the concave surface of the first expansion lens 10, the exit angle should be designed to be as large as possible. The concave surface can be designed as a spherical surface, and the traditional optical cold processing technology is adopted, which has a relatively low cost.

[0073] Both optical surfaces can be coated with AR film, and the reflectivity is less than 0.5%.

[0074] In an embodiment, on the basis of the above embodiment, the second beam expanding lens 6 is a plano-concave lens, and the plane faces the second laser source 5, and the concave surface faces the fourth collimating lens 7.

[0075] In the embodiment, the second beam expanding lens 6 can be made by the same process as the first beam expanding lens 10.

[0076] The plane of the second beam expanding lens 6 is close to the second laser source 5, and the concave surface is away from the second laser source 5. The concave surface mainly plays a role in diverging and expanding the light.

[0077] In an embodiment, on the basis of the above embodiment, the third collimating lens 11 is a meniscus lens, and the concave surface faces the first beam expanding lens 10, and the convex surface faces the transmission surface of the second dichroic mirror 12.

[0078] In the embodiment, the third collimating lens 11 is a meniscus lens with a positive focal length.

[0079] Optionally, the central thickness of the third collimating lens 11 is 14.8 mm, the curvature radius of the concave surface is R30 mm, the curvature radius of the convex surface is R18.161 mm, and the diameter is Ø35 mm.

[0080] The concave surface of the third collimating lens 11 is close to the first beam expanding lens 10, and the convex surface is away from the first beam expanding lens 10. This is because the concave surface of the third collimating lens 11 can again diverge and uniform the light, and finally the light is converged to collimated parallel light through the convex surface. The focal length of the third collimating lens 11 is moderate, and the optical glass material H-ZF2 can be selected, which is relatively cheap. Both optical surfaces are spherical surfaces, and the traditional optical cold processing technology can be used, which is relatively low in cost.

[0081] Both optical surfaces can be coated with AR film with a reflectivity of <0.5%.

[0082] In an embodiment, on the basis of the above embodiment, the fourth collimating lens 7 is a meniscus lens, and the concave surface faces the second beam expanding lens 6, and the convex surface faces the mirror 8.

[0083] In the embodiment, the fourth collimating lens 7 can be made by the same process as the third collimating lens 11.

[0084] The concave surface of the fourth collimating lens 7 is close to the second beam expanding lens 6, and the convex surface is away from the second beam expanding lens 6. This is because the concave surface of the fourth collimating lens 7 can again diverge and uniform the light, and finally the light is converged to collimated parallel light through the convex surface.

[0085] In an embodiment, on the basis of the above embodiment, the first focusing lens 13 is a plano-convex lens, and the plane is towards the second focusing lens 14, and the convex surface is towards the reflecting surface of the first dichroic mirror 4.

[0086] In the embodiment, the first focusing lens 13 is a plano-convex lens, and has positive optical power.

[0087] Optionally, the central thickness of the first focusing lens 13 is 8.5mm, the convex surface has a curvature radius of R4 2.4mm, and the diameter is Ø43mm.

[0088] According to the symmetry of the optical system, the optical power of the first focusing lens 13 should be close to that of the second collimating lens 3. Therefore, the first focusing lens 13 can also be designed as a plano-convex lens with positive optical power, and the convex surface is close to the first dichroic mirror 4, and the plane is away from the first dichroic mirror 4. The first focusing lens 13 needs to bear relatively small optical power, and can select low refractive index and high transmittance optical glass material H-K9L, and design the convex surface as a spherical surface, and use traditional optical cold processing technology, which has relatively low cost.

[0089] Both optical surfaces can be coated with AR film, and the reflectivity is less than 0.5%.

[0090] In an embodiment, on the basis of the above embodiment, the second focusing lens 14 is a meniscus lens, and the concave surface is towards the filter 15, and the convex surface is towards the first focusing lens 13.

[0091] In the embodiment, the second focusing lens 14 is a meniscus lens, and has positive optical power.

[0092] Optionally, the central thickness of the second focusing lens 14 is 8mm, the concave surface has a curvature radius of R3 5.1mm, the convex surface has a curvature radius of R2 2.1mm, and the diameter is Ø35mm.

[0093] According to the symmetry of the optical system, the optical power of the second focusing lens 14 should be close to that of the first collimating lens 2. Because the light spot needs to be converged, the second focusing lens 14 needs to bear relatively large optical power. Similarly, the second focusing lens 14 can be designed as a meniscus lens with positive optical power, and the convex surface is close to the first focusing lens 13, and the concave surface is away from the first focusing lens 13. The second focusing lens 14 needs to bear most of the optical power to converge the light into the light guide rod 16, and therefore, high refractive index optical glass material heavy lanthanum flint glass H-ZLAF92 can be selected, so that the curvature of the lens can be designed to be small, which is convenient for processing and production, and the two optical surfaces of the lens are designed as spherical surfaces, and traditional optical cold processing technology is used, which has relatively low cost.

[0094] Both optical surfaces can be coated with AR film, reflectivity <0.5%.

[0095] The focusing lens group composed of the first focusing lens 13 and the second focusing lens 14 and the white light collimating lens group are relatively symmetrical optical system structures, which are more conducive to coupling light into the light guide rod 16. It should be noted that the optical power of the focusing lens group is smaller than that of the white light collimating lens group, so that the focusing spot size and the edge light angle can better match the numerical aperture NA and the light transmission aperture of the light guide beam. Taking a light guide beam with a numerical aperture NA of 0.57 and a diameter of 5mm as an example, the numerical aperture NA of the focusing spot should be less than or equal to 0.57, that is, the maximum angle of the light should be less than or equal to 69.5°, and the diameter should be less than or equal to 5mm, so that the optical transmission coupling efficiency of the light guide beam can be maximized.

[0096] In an embodiment, based on the above embodiment, taking the white light source 1 as a 400-700nm white light LED, the first laser source 9 as a 660nm semiconductor laser, and the second laser source 5 as a 785nm semiconductor laser as an example:

[0097] Optionally, the transmission surface of the first dichroic mirror 4 is coated with a 400-650nm white light transmission film, and the reflection surface of the first dichroic mirror 4 is coated with a 650-800nm infrared laser reflection film; the first dichroic mirror 4 is a flat glass with an optical power of 0, and the optional thickness is 1.1mm and the material is H-K9L.

[0098] Optionally, the first dichroic mirror 4 can pass 400-650nm white light and reflect 650-800nm laser (i.e. near-infrared laser) by multi-layer optical coating. The process is optical vacuum evaporation coating, and the substrate can be ordinary optical glass. In order to save cost and improve light transmittance, high transmittance optical glass material H-K9L can be selected. By double-sided coating (such as AR coating on the transmission surface and dichroic coating on the reflection surface), the transmittance of 400-650nm white light can reach more than 96%, and the reflectivity of 650-800nm near-infrared laser can reach more than 98%. In this way, the light energy loss is relatively small.

[0099] Optionally, the transmission surface of the second dichroic mirror 12 is coated with a 660nm infrared laser transmission film, and the reflection surface of the second dichroic mirror 12 is coated with a 785nm infrared laser reflection film; the second dichroic mirror 12 is a flat glass with an optical power of 0, and the optional thickness is 1.1mm and the material is H-K9L.

[0100] Optionally, the second dichroic mirror 12 can be made of multi-layer optical coating to transmit 660nm white light and reflect 785nm laser (i.e. near-infrared laser). The process is optical vacuum evaporation coating, and the substrate can be ordinary optical glass. In order to save cost and improve light transmittance, high transmittance optical glass material H-K9L can be selected. By using double-sided coating (such as transmissive surface coated with AR film, such as 660nm laser anti-reflection film; reflective surface coated with dichroic film), the transmittance of 660nm laser can reach more than 96%, and the reflectivity of 785nm near-infrared laser can reach more than 98%. In this way, the light energy loss is relatively small.

[0101] Optionally, the mirror 8 can be used to reflect 785nm laser, and a second dichroic mirror 12 can be used instead (i.e. another reflective surface of the second dichroic mirror 12 is used instead of the mirror 8) to simplify the complexity of the illumination system preparation.

[0102] In an embodiment, on the basis of the above embodiment, the optical filter 15 can be prepared by optical vacuum evaporation coating technology, and the substrate can be ordinary optical glass. In order to save cost and improve light transmittance, high transmittance optical glass material H-K9L can be selected.

[0103] In an embodiment, on the basis of the above embodiment, the light guide rod 16 can be a glass cylinder.

[0104] Optionally, the optical power of the light guide rod 16 is 0, the thickness is 10mm, the diameter is Ø5mm, and the material is H-K9L.

[0105] Optionally, the diameter of the light guide rod 16 should be consistent with the clear aperture of the light guide beam, such as both being Ø5mm, so that the coupling efficiency between the light guide beam and the optical system can be highest.

[0106] The light guide rod 16 can be made of ordinary optical glass. In order to save cost and improve light transmittance, high transmittance optical glass material H-K9L can be selected.

[0107] Since the light needs to be totally reflected inside the cylindrical surface of the light guide rod 16, both the two planes and the cylindrical surface need to be cold worked and polished, and the surface quality is 60-40.

[0108] Since the cylindrical surface of the light guide rod 16 needs to be coated with UV glue during installation, the refractive index of the glue will destroy the total reflection condition of the light, so the cylindrical surface needs to be coated with a metal reflective film. The reflective film can be prepared by chemical plating, and the reflectivity is >92%. Both optical planes (end faces) can be coated with AR film, which is prepared by optical vacuum evaporation coating technology, and the reflectivity is <0.5%.

[0109] In addition, the application further provides a medical endoscope comprising the illumination system of the medical endoscope according to the above-mentioned embodiments, and the specific structure of the illumination system is referred to the above-mentioned embodiments. Since the medical endoscope adopts all the technical solutions of the above-mentioned embodiments, it has at least all the technical effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0110] In summary, for the illumination system of the medical endoscope and the medical endoscope provided in the embodiments of the application, the lenses in the illumination system all adopt spherical lenses with relatively simple processing technology, which greatly reduces the manufacturing cost of the illumination system. In addition, the illumination system can not only provide white light illumination, but also provide two different laser illuminations, so as to meet the dual fluorescence imaging requirement of the medical endoscope. At the same time, by reasonably arranging the positions and angles of the lenses and optimizing the distribution of the light field, the illumination system can provide a uniform light field. Moreover, even if spherical lenses are used, by accurate optical design and adjustment, the illumination system can still achieve high optical transmission efficiency.

[0111] It should be noted that in this document, the terms "comprising", "containing", or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, device, article or method. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of another identical element in the process, device, article or method including the element.

[0112] The above-mentioned is only the preferred embodiment of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process transformation according to the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the application.

Claims

1. An illumination system of a medical endoscope, characterized by, The illumination system comprises: a first collimating lens, a second collimating lens, a first dichroic mirror, a first focusing lens, a second focusing lens and a filter arranged in sequence from the white light source to the light guide rod, and the transmission surface of the first dichroic mirror is at a 45° angle towards the second collimating lens, and the reflection surface of the first dichroic mirror is at a 45° angle towards the first focusing lens; In a direction which is at a 45° angle with the reflection surface of the first dichroic mirror and is perpendicular to the direction from the white light source to the light guide rod, a first expansion lens, a third collimating lens and a second dichroic mirror are further arranged in sequence from the first laser source to the reflection surface of the first dichroic mirror; wherein the second dichroic mirror is parallel to the first dichroic mirror, and the reflection surface of the second dichroic mirror is towards the first dichroic mirror, and the transmission surface of the second dichroic mirror is towards the third collimating lens; In a direction which is perpendicular to the direction from the white light source to the light guide rod, a second expansion lens and a fourth collimating lens are further arranged in sequence from the second laser source to the mirror; wherein the mirror is parallel to the second dichroic mirror and is towards the reflection surface of the second dichroic mirror; Wherein the first collimating lens, the second collimating lens, the third collimating lens, the fourth collimating lens, the first focusing lens, the second focusing lens, the first expansion lens and the second expansion lens are all spherical lenses; the laser wavelengths emitted by the first laser source and the second laser source are different; The first collimating lens is a meniscus lens, and the concave surface is towards the white light source, and the convex surface is towards the second collimating lens; the second collimating lens is a plano-convex lens, and the plane is towards the first collimating lens, and the convex surface is towards the transmission surface of the first dichroic mirror; the first focusing lens is a plano-convex lens, and the plane is towards the second focusing lens, and the convex surface is towards the reflection surface of the first dichroic mirror; the second focusing lens is a meniscus lens, and the concave surface is towards the filter, and the convex surface is towards the first focusing lens; The focusing lens group composed of the first focusing lens and the second focusing lens, and the white light collimating lens group composed of the first collimating lens and the second collimating lens are relatively symmetrical optical system structures, and the optical power of the focusing lens group is less than the optical power of the white light collimating lens group, so that the light is coupled into the light guide rod; The light guide beam is arranged on the light emitting surface of the light guide rod, and the diameter of the light guide rod is consistent with the light passing aperture of the light guide beam; the light guide rod is a glass cylinder, and the material is H-K9L, and the two planes and the cylindrical surface of the light guide rod are all subjected to cold processing and polishing treatment, and the cylindrical surface is coated with a metal reflective film; The type of the filter includes two types, one of which is used for transmitting white light and cutting off laser, and the other of which is used for transmitting laser and cutting off white light; and the two types of filters are switched back and forth by using a motor drive; when the illumination system uses a white light source for illumination, the filter is switched to transmit white light and cut off laser; when the illumination system uses a first laser source or a second laser source for illumination, the filter is switched to transmit laser and cut off white light.

2. The illumination system of a medical endoscope according to claim 1, wherein The first expansion lens is a plano-concave lens, and the plane is towards the first laser source, and the concave surface is towards the third collimating lens.

3. The illumination system of a medical endoscope according to claim 1, wherein The second expansion lens is a plano-concave lens, and the plane is towards the second laser source, and the concave surface is towards the fourth collimating lens.

4. The illumination system of a medical endoscope according to claim 1, wherein The third collimating lens is a meniscus lens, and the concave surface faces the first beam expanding lens and the convex surface faces the transmission surface of the second dichroic mirror.

5. The illumination system of a medical endoscope according to claim 1, wherein The fourth collimating lens is a meniscus lens, and the concave surface faces the second beam expanding lens and the convex surface faces the mirror.

6. A medical endoscope characterized by comprising: An illumination system for a medical endoscope comprising a medical endoscope according to any one of claims 1-5.

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