Illumination optical system

Abstract

The utility model relates to the technology of optical elements, and discloses an illumination optical system which comprises a first collimating lens, a second collimating lens, a dichroscope, a first focusing lens, a second focusing lens and an optical filter which are sequentially arranged in the direction from a white light source to a light guide rod. The transmission surface of the dichroscope faces the second collimating lens at an angle of 45 degrees, and the reflection surface of the dichroscope faces the first focusing lens at an angle of 45 degrees; a beam expanding lens and a third collimating lens are sequentially arranged between the laser light source and the reflecting surface of the dichroscope in a direction which forms an included angle of 45 degrees with the reflecting surface of the dichroscope and is vertical to the direction from the white light source to the light guide rod; wherein the first collimating lens, the second collimating lens, the third collimating lens, the first focusing lens, the second focusing lens and the beam expanding lens are spherical lenses. The utility model aims to provide an illumination optical system capable of adopting a spherical lens so as to reduce the preparation cost of the illumination optical system.

Description

Technical Field

[0001] The utility model relates to the technical field of optical elements, in particular to an illumination optical system. Background Art

[0002] Endoscopic technology plays a vital role in modern medicine, allowing doctors to examine and treat patients' internal organs without undergoing major surgery. Lighting modules are a crucial component of endoscopy systems, providing the necessary illumination for the endoscope to ensure doctors can clearly see the affected area.

[0003] Traditional endoscope illumination modules are typically designed with aspheric glass lenses to reduce optical aberrations and improve image quality. However, the processing of aspheric lenses is complex, especially when using a molding process, which leads to relatively high costs. This limits the widespread application of endoscope illumination modules, especially in cost-sensitive medical environments.

[0004] Therefore, there is an urgent need for a new type of illumination optical system design that can ensure optical performance while reducing system preparation costs to meet the needs of current medical endoscope applications.

[0005] The above content is only used to assist in understanding the technical solution of the present invention and does not constitute an admission that the above content is prior art. Utility Model Content

[0006] The utility model provides an illumination optical system, aiming to provide an illumination optical system that can adopt a spherical lens, so as to reduce the preparation cost of the illumination optical system.

[0007] To achieve the above-mentioned object, the present invention provides an illumination optical system, comprising: a first collimating lens, a second collimating lens, a dichroic mirror, a first focusing lens, a second focusing lens, and a filter, which are arranged in sequence from a white light source to a light guide rod, wherein the transmission surface of the dichroic mirror is at a 45° angle toward the second collimating lens, and the reflection surface of the dichroic mirror is at a 45° angle toward the first focusing lens;

[0008] A beam expander lens and a third collimator lens are sequentially provided between the laser light source and the reflecting surface of the dichroic mirror at a 45° angle to the reflecting surface of the dichroic mirror and perpendicular to the direction from the white light source to the light guide rod;

[0009] The first collimating lens, the second collimating lens, the third collimating lens, the first focusing lens, the second focusing lens and the beam expanding lens are all spherical lenses.

[0010] Optionally, the first collimating lens is a meniscus lens, with the concave surface facing the white light source and the convex surface facing the second collimating lens.

[0011] Optionally, the second collimating lens is a plano-convex lens, with its flat surface facing the first collimating lens and its convex surface facing the transmission surface of the dichroic mirror.

[0012] Optionally, the beam expander lens is a plano-concave lens, with the flat surface facing the laser light source and the concave surface facing the third collimating lens.

[0013] Optionally, the third collimating lens is a meniscus lens, with a concave surface facing the beam expander lens and a convex surface facing the reflective surface of the dichroic mirror.

[0014] Optionally, the first focusing lens is a plano-convex lens, with its flat surface facing the second focusing lens and its convex surface facing the reflective surface of the dichroic mirror.

[0015] Optionally, the second focusing lens is a meniscus lens, with the concave surface facing the filter and the convex surface facing the first focusing lens.

[0016] Optionally, the filter includes two types of filters; one filter is used to transmit white light and cut off laser light, and the other filter is used to transmit laser light and cut off white light.

[0017] Optionally, the light guide rod is arranged at the light focusing focus of the second focusing lens.

[0018] Optionally, the illumination optical system is an illumination optical system of a medical endoscope.

[0019] The beneficial effects of the technical solution of the present utility model are as follows: the lenses in the illumination optical system all adopt spherical lenses with relatively simple processing technology, which greatly reduces the manufacturing cost of the illumination optical system; at the same time, by rationally arranging the lens positions and angles, the distribution of the light field can be optimized, so that the illumination system can provide a uniform light field; and even when using spherical lenses, the illumination optical system can still achieve high optical transmission efficiency through precise optical design and adjustment.

[0020] Since the illumination optical system has good optical properties such as uniform light field and high optical transmission efficiency, it can improve image quality and reduce spot effect in the application of medical endoscopes, and meet the requirements of high brightness and high illumination uniformity of medical endoscopes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of an embodiment of the illumination optical system of the present invention.

[0022] Description of reference numerals:

[0023] 1. White light source; 2. First collimating lens; 3. Second collimating lens; 4. Laser light source; 5. Beam expander lens; 6. Third collimating lens; 7. Dichroic mirror; 8. First focusing lens; 9. Second focusing lens; 10. Filter; 11. Light guide rod.

[0024] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the schemes in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0027] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element.

[0028] Furthermore, if terms such as "first" or "second" are used in this utility model, they are used solely for descriptive purposes (e.g., to distinguish identical or similar components) and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include at least one such feature. Furthermore, the technical solutions of various embodiments may be combined, but only if they are achievable by persons of ordinary skill in the art. If a combination of technical solutions contradicts or is unachievable, such combination shall be deemed non-existent and outside the scope of protection claimed by this utility model.

[0029] The utility model proposes an illumination optical system, referring to Figure 1The illumination optical system includes a first collimating lens 2, a second collimating lens 3, a dichroic mirror 7, a first focusing lens 8, a second focusing lens 9 and a filter 10, which are arranged in sequence from the white light source 1 to the light guide rod 11, and the transmission surface of the dichroic mirror 7 is at a 45° angle toward the second collimating lens 3, and the reflection surface of the dichroic mirror 7 is at a 45° angle toward the first focusing lens 8;

[0030] In a direction perpendicular to the direction from the white light source 1 to the light guide rod 11 and at an angle of 45° to the reflection surface of the dichroic mirror 7, a beam expander lens 5 and a third collimating lens 6 are sequentially provided between the laser light source 4 and the reflection surface of the dichroic mirror 7;

[0031] The first collimating lens 2 , the second collimating lens 3 , the third collimating lens 6 , the first focusing lens 8 , the second focusing lens 9 and the beam expander lens 5 are all spherical lenses.

[0032] In this embodiment, the white light source 1 is used to provide white light and emit the white light toward 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.

[0033] The first collimating lens 2 is a lens with positive optical power, and is used to converge the white light emitted by the white light source 1 to the second collimating lens 3 .

[0034] The second collimating lens 3 is a lens with positive refractive power, and is used to further converge the white light converged by the first focusing lens 8 and make it incident on the transmission surface of the dichroic mirror 7 at an angle of 45°.

[0035] Optionally, the body of the dichroic mirror 7 is flat glass with an optical focal length of 0; wherein, one side of the transmission surface of the dichroic mirror 7 is coated with a transmission film for transmitting white light; and one side of the reflection surface of the dichroic mirror 7 is coated with a reflection film for reflecting laser light.

[0036] The transmission surface of the dichroic mirror 7 is used to transmit the white light further focused by the second focusing lens 9 to the first focusing lens 8 .

[0037] The laser light source 4 is used to provide laser light and emit the laser light toward the beam expander lens 5. The laser light source 4 can be a 785 nm semiconductor laser, that is, the laser light can be a 785 nm near-infrared laser.

[0038] The beam expander lens 5 is a lens with negative optical power, and is used to perform divergent beam expansion and homogenization processing on the laser light emitted by the laser light source 4 , and scatter the processed laser light to the third collimating lens 6 .

[0039] The third collimating lens 6 is a lens with positive refractive power, and is used to converge the diffused laser light into collimated parallel laser light, and make the parallel laser light incident on the reflecting surface of the dichroic mirror 7 at an angle of 45°.

[0040] The reflective surface of the dichroic mirror 7 is used to reflect the laser light at an angle of 90° to the first focusing lens 8 .

[0041] The first focusing lens 8 is a lens with positive optical power, and is used to focus the incident white light and laser light onto the second focusing lens 9 .

[0042] The second focusing lens 9 is a lens with positive optical power, which is used to further focus the incident white light and laser light. A filter 10 is also provided between the second focusing lens 9 and the light focusing point of the second focusing lens 9.

[0043] The filter 10 is used to selectively filter the light focused by the second focusing lens 9. For white light, the filter 10 is used to transmit white light and cut off laser light; for white light, the filter 10 is used to transmit laser light and cut off white light. Two types of filters 10 can be provided: one filter 10 transmits white light and cuts off laser light, and the other filter 10 transmits laser light and cuts off white light. The two filters 10 can be switched back and forth using a motor drive according to specific filtering requirements.

[0044] The optical focal length of the light guide rod 11 is 0 and it is set at the light focusing point of the second focusing lens 9. Firstly, it is used to stagger 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; secondly, it can play the role of light uniformity.

[0045] Optionally, when the illumination optical 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 dichroic mirror 7, the first focusing lens 8, the second focusing lens 9, and the filter 10 in sequence, and is finally coupled into the light guide rod 11. The guide light beam is connected to the light emitting end face of the light guide rod 11, and the light can be coupled into the guide light beam.

[0046] Because the divergence angle of white light source 1 is typically large (up to 120°), the white light must first be collimated to reduce the divergence angle and spot size, facilitating light coupling into the light guide. The first collimating lens 2 and the second collimating lens 3 form a white light collimating lens assembly, whose primary function is to collimate the large-angle white light into parallel light. The white light collimating lens assembly is constructed of spherical glass lenses, enabling the use of traditional optical cold processing techniques, resulting in relatively low costs.

[0047] Collimated white light passes through dichroic mirror 7, where it is split. The mirror's function is to transmit the white light and reflect the laser beam. Therefore, the white light is completely transmitted through dichroic mirror 7. Furthermore, dichroic mirror 7 is a flat plate and does not provide optical power, so it does not change the direction of light propagation. The white light remains collimated after passing through dichroic mirror 7.

[0048] The first focusing lens 8 and the second focusing lens 9 form a focusing lens group, whose main function is to focus the collimated light passing through the dichroic mirror 7 and couple it into the light guide rod 11. What needs to be considered here is that the light guide has an NA value and a light-clearance diameter. Therefore, the image-side NA of the light converged by the focusing lens group must be less than or equal to the NA value of the light guide, and the focused light spot must be less than or equal to the light-clearance diameter of the light guide, so that the light can be coupled into the light guide to the maximum extent, which can reduce the loss of light energy. Moreover, the focusing lens groups are all designed as spherical glass lenses, and traditional optical cold processing technology can be used, and the cost is relatively low. There is a filter 10 between the focusing lens group and the light guide rod 11. At this time, the filter 10 is switched to allow white light to pass through and cut off the laser.

[0049] After the white light passes through the focusing lens group and the filter 10, it can be coupled into the light guide rod 11 at a certain angle and spot size. Since the energy and temperature at the focus are very high, if the light-incident end face of the light guide beam is placed directly at the focus of the light, the extremely high temperature may burn the light guide beam. Therefore, a light guide rod 11 must be added at the focus, and the light guide beam can be placed on the light-emitting surface of the light guide rod 11, thereby avoiding the focus, protecting the light guide beam, and extending the service life of the light guide beam. Moreover, the light is totally reflected inside the light guide rod 11, which can achieve a certain uniform light effect. Therefore, the material of the light guide rod 11 can be an optical glass material that is resistant to high temperatures and has good light transmittance.

[0050] Optionally, when the illumination optical system uses laser illumination, near-infrared laser light is emitted by laser light source 4, passes through beam expander lens 5 and third collimator lens 6 in sequence, is reflected at a 90° angle by the reflective surface of dichroic mirror 7, enters the focusing lens group, and after being focused, passes through filter 10 and is coupled into light guide rod 11. The light guide is connected to the light-emitting end face of light guide rod 11, and the light is coupled into the light guide.

[0051] Because the laser's divergence angle is relatively small and its beam distribution is Gaussian, its energy is essentially concentrated within a small angle range. Therefore, the laser must first be diverged, expanded, and homogenized. The beam expander lens 5 can expand the laser's divergence angle and homogenize the laser's light field distribution. Furthermore, the beam expander lens 5 is a spherical glass lens design, which can be processed using traditional optical cold processing techniques, resulting in relatively low costs.

[0052] After the laser beam is diverged and expanded, it needs to be collimated before it can be coupled into the focusing lens group. The third collimating lens 6 can collimate the divergent light into parallel light, and the collimated light spot size is consistent with that of white light, which is more conducive to focusing and coupling into the light guide rod 11. The third collimating lens 6 is designed as a spherical glass lens, which can adopt traditional optical cold processing technology, and the cost is relatively low.

[0053] After being shaped into collimated parallel light by the third collimating lens 6, the laser is reflected by the reflective surface of the dichroic mirror 7, with the angle between the reflective surface and the laser light being 45°. The dichroic mirror 7 reflects the laser light into the focusing lens group. Like white light, the laser light is converged by the focusing lens group and passes through the optical filter 10 (which is now switched to transmit the laser light and cut off near-white light). It is ultimately coupled into the light guide rod 11 at a specific angle and spot size. Connecting the light guide to the light-emitting end face of the light guide rod 11 allows the light to be coupled into the light guide.

[0054] The first collimating lens 2, the second collimating lens 3, the third collimating lens 6, the first focusing lens 8, the second focusing lens 9, and the beam expander lens 5 are all spherical lenses (e.g., spherical glass lenses). These lenses are manufactured using traditional optical cold working techniques, resulting in relatively low costs. While achieving low costs, this illumination optical system also achieves extremely high optical transmission efficiency and excellent light field distribution uniformity.

[0055] In one embodiment, the lenses in the illumination optical system are all spherical lenses with relatively simple processing technology, which greatly reduces the manufacturing cost of the illumination optical system; at the same time, by reasonably arranging the lens positions and angles, the distribution of the light field can be optimized, so that the illumination system can provide a uniform light field; and even if spherical lenses are used, through precise optical design and adjustment, the illumination optical system can still achieve high optical transmission efficiency.

[0056] Since the illumination optical system has good optical properties such as uniform light field and high optical transmission efficiency, it can improve image quality and reduce spot effect in the application of medical endoscopes, and meet the requirements of high brightness and high illumination uniformity of medical endoscopes.

[0057] In one embodiment, based on the above embodiment, the first collimating lens 2 is a meniscus lens, with the concave surface facing the white light source 1 and the convex surface facing 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 center thickness of the first collimating lens 2 is 13.9 mm, the concave curvature radius is R32.2 mm, the convex curvature radius is R18.2 mm, and the diameter is Ø35 mm.

[0060] Since it is necessary to receive as much wide-angle light coupled to the white light source 1 as possible, the concave surface needs to be closer to the white light source 1 and the convex surface needs to be farther away from the white light source 1. In the collimating lens assembly, the first collimating lens 2 needs to bear most of the optical focal length to converge the wide-angle white light. Therefore, a high-refractive-index optical glass material, heavy lanthanum flint glass H-ZLAF92, can be selected. This allows for a smaller curvature of the lens, facilitating easier processing. Both optical surfaces of the lens are spherical, allowing for the use of traditional optical cold processing techniques at a relatively low cost.

[0061] Both optical surfaces can be coated with AR coating with a reflectivity of <0.5%.

[0062] In one embodiment, based on the above embodiment, the second collimating lens 3 is a plano-convex lens, with its flat surface facing the first collimating lens 2 and its convex surface facing the transmission surface of the dichroic mirror 7 .

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

[0064] Optionally, the center thickness of the second collimating lens 3 is 10 mm, the convex surface 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 assumed most of the optical focal length, the optical focal length of the second collimating lens 3 can be relatively small, so that the optical glass material H-K9L with low refractive index and high transmittance can be selected. In order to save production and processing costs, it can be designed as a plano-convex lens with positive optical focal length, with the plane of the plano-convex lens close to the side of the first collimating lens 2 and the convex surface away from the side of the first collimating lens 2. The convex surface is designed to be 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 coating with a reflectivity of <0.5%.

[0067] In one embodiment, based on the above embodiment, taking the white light source 1 as a 400~700nm white light LED and the laser light source 4 as a 785nm semiconductor laser as an example, the transmission surface of the dichroic mirror 7 is coated with a 400~700nm white light transmission film, and the reflection surface of the dichroic mirror 7 is coated with a 785nm infrared laser reflection film.

[0068] Optionally, the dichroic mirror 7 is made of flat glass, has an optical power of 0, an optional thickness of 1.1 mm, and is made of H-K9L.

[0069] Multi-layer optical coatings can transmit white light from 400 to 700 nm and reflect lasers at 785 nm (near-infrared lasers). This process uses vacuum evaporation coating, and the substrate can be ordinary optical glass. To save costs and improve light transmittance, high-transmittance optical glass material H-K9L can be selected. Double-sided coating achieves a transmittance of over 96% for white light from 400 to 700 nm and a reflectivity of over 98% for near-infrared lasers at 785 nm, minimizing light energy loss.

[0070] In one embodiment, based on the above embodiment, the beam expander lens 5 is a plano-concave lens, with the flat surface facing the laser light source 4 and the concave surface facing the third collimating lens 6 .

[0071] In this embodiment, the beam expander lens 5 is a plano-concave lens with negative optical power.

[0072] Optionally, the center thickness of the beam expander lens 5 is 6 mm, the concave curvature radius is R17.272 mm, and the diameter is Ø24 mm.

[0073] In order to save costs, the beam expander lens 5 can be designed as a plano-concave lens, with the flat surface of the lens close to the laser light source 4 and the concave surface away from the laser light source 4. The concave surface mainly plays the role of diverging, expanding and homogenizing light.

[0074] To save costs and improve light transmittance, the beam expander lens 5 can be made of high-transmittance optical glass material H-K9L. After the laser light passes through the concave surface of the beam expander lens 5, the exit angle should be designed to be as large as possible. The concave surface can be designed as a spherical surface, using traditional optical cold processing technology, which is relatively cost-effective.

[0075] Two optical surfaces can be coated with AR film with a reflectivity of <0.5%.

[0076] In one embodiment, based on the above embodiment, the third collimating lens 6 is a meniscus lens, with a concave surface facing the beam expander lens 5 and a convex surface facing the reflective surface of the dichroic mirror 7 .

[0077] In this embodiment, the third collimating lens 6 is a meniscus lens with positive power.

[0078] Optionally, the third collimating lens 6 has a center thickness of 14.8 mm, a concave curvature radius of R30 mm, a convex curvature radius of R18.161 mm, and a diameter of Ø35 mm.

[0079] The concave surface of the third collimating lens 6 is closer to the side of the collimating lens 5, and the convex surface is farther away from the side of the collimating lens 5. This is because the concave surface of the third collimating lens 6 can further diverge and even the laser light, and finally converge it into collimated parallel light through the convex surface. The optical focal length of the third collimating lens 6 is medium, and the optical glass material H-ZF2 can be selected, which is relatively cheap. Both optical surfaces are spherical, and traditional optical cold processing technology can be used, which is relatively low in cost.

[0080] Both optical surfaces can be coated with AR coating with a reflectivity of <0.5%.

[0081] In one embodiment, based on the above embodiment, the first focusing lens 8 is a plano-convex lens, with its flat surface facing the second focusing lens 9 and its convex surface facing the reflective surface of the dichroic mirror 7 .

[0082] In this embodiment, the first focusing lens 8 is a plano-convex lens with positive optical power.

[0083] Optionally, the center thickness of the first focusing lens 8 is 8.5 mm, the convex surface curvature radius is R42.4 mm, and the diameter is Ø43 mm.

[0084] Based on the symmetry of the optical system, the optical power of the first focusing lens 8 should be close to that of the second collimating lens 3. Therefore, the first focusing lens 8 can also be designed as a plano-convex lens with positive optical power, with the convex surface closer to the dichroic mirror 7 and the flat surface farther away from the dichroic mirror 7. The optical power required of the first focusing lens 8 is relatively small, so the low-refractive-index, high-transmittance optical glass material H-K9L can be selected, and the convex surface can be designed as a spherical surface. Traditional optical cold working techniques are used, resulting in relatively low costs.

[0085] Both optical surfaces can be coated with AR coating with a reflectivity of <0.5%.

[0086] In one embodiment, based on the above embodiment, the second focusing lens 9 is a meniscus lens, with the concave surface facing the filter 10 and the convex surface facing the first focusing lens 8 .

[0087] In this embodiment, the second focusing lens 9 is a meniscus lens with positive optical power.

[0088] Optionally, the center thickness of the second focusing lens 9 is 8 mm, the curvature radius of the concave surface is R35.1 mm, the curvature radius of the convex surface is R22.1 mm, and the diameter is Ø35 mm.

[0089] According to the symmetry of the optical system, the optical focal length of the second focusing lens 9 should be close to that of the first collimating lens 2. Because the light spot needs to be converged, the optical focal length that the second focusing lens 9 needs to bear is also relatively large. Similarly, the second focusing lens 9 can be designed as a meniscus lens with positive optical focal length, with the convex surface of the lens close to the side of the first focusing lens 8 and the concave surface of the lens away from the side of the first focusing lens 8. The second focusing lens 9 needs to bear most of the optical focal length in order to converge and couple the large-angle light of white light into the light guide rod 11. Therefore, a high-refractive-index optical glass material, heavy lanthanum flint glass H-ZLAF92, can be selected. In this way, 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 designed to be spherical. The traditional optical cold processing technology is used, and the cost is relatively low.

[0090] Both optical surfaces can be coated with AR coating with a reflectivity of <0.5%.

[0091] In one embodiment, based on the above embodiment, the filter 10 can be prepared by optical vacuum evaporation coating technology, and the substrate can be ordinary optical glass. In order to save costs and improve light transmittance, a high-transmittance optical glass material H-K9L can be selected.

[0092] In one embodiment, based on the above embodiment, the light guide rod 11 may be a glass cylinder.

[0093] Optionally, the light guide rod 11 has an optical focal length of 0, a thickness of 10 mm, a diameter of Ø5 mm, and is made of H-K9L.

[0094] Optionally, the diameter of the light guide rod 11 should be consistent with the light aperture of the light guide beam, such as Ø5 mm, so that the coupling efficiency between the light guide beam and the optical system can be maximized.

[0095] The light guide rod 11 can be made of ordinary optical glass. In order to save costs and improve light transmittance, high-transmittance optical glass material H-K9L can be selected.

[0096] Since the light needs to be totally reflected on the inner side of the cylindrical surface of the light guide rod 11, the two planes and one cylindrical surface need to be cold-processed and polished with a surface quality of 60-40.

[0097] Because the cylindrical surface of the light guide rod 11 needs to be coated with UV glue during installation, the refractive index of the glue will affect the total reflection of light. Therefore, the cylindrical surface needs to be coated with a metal reflective film. The reflective film can be prepared by chemical plating and has a reflectivity of >92%. Both optical surfaces (end faces) can be coated with AR film using optical vacuum evaporation technology with a reflectivity of <0.5%.

[0098] In one embodiment, based on the above embodiment, the illumination optical system is an illumination optical system of a medical endoscope.

[0099] The above description is only part or preferred embodiments of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.

Claims

1. An illumination optical system, characterized in that: include: A first collimating lens, a second collimating lens, a dichroic mirror, a first focusing lens, a second focusing lens, and a filter are sequentially arranged from the white light source to the light guide rod, wherein the transmission surface of the dichroic mirror is at a 45° angle toward the second collimating lens, and the reflection surface of the dichroic mirror is at a 45° angle toward the first focusing lens; A beam expander lens and a third collimator lens are sequentially provided between the laser light source and the reflecting surface of the dichroic mirror at a 45° angle to the reflecting surface of the dichroic mirror and perpendicular to the direction from the white light source to the light guide rod; The first collimating lens, the second collimating lens, the third collimating lens, the first focusing lens, the second focusing lens and the beam expanding lens are all spherical lenses.

2. The illumination optical system according to claim 1, wherein The first collimating lens is a meniscus lens, with a concave surface facing the white light source and a convex surface facing the second collimating lens.

3. The illumination optical system according to claim 1, wherein The second collimating lens is a plano-convex lens, with its flat surface facing the first collimating lens and its convex surface facing the transmission surface of the dichroic mirror.

4. The illumination optical system according to claim 1, wherein The beam expander lens is a plano-concave lens, with its flat surface facing the laser light source and its concave surface facing the third collimating lens.

5. The illumination optical system according to claim 1, wherein The third collimating lens is a meniscus lens, with a concave surface facing the beam expander lens and a convex surface facing the reflective surface of the dichroic mirror.

6. The illumination optical system according to claim 1, wherein The first focusing lens is a plano-convex lens, with a flat surface facing the second focusing lens and a convex surface facing the reflective surface of the dichroic mirror.

7. The illumination optical system according to claim 1, wherein The second focusing lens is a meniscus lens, with a concave surface facing the filter and a convex surface facing the first focusing lens.

8. The illumination optical system according to claim 1, wherein The optical filter includes two types of filters; one filter is used to transmit white light and cut off laser light, and the other filter is used to transmit laser light and cut off white light.

9. The illumination optical system according to claim 1, wherein: The light guide rod is arranged at the light focusing point of the second focusing lens.

10. The illumination optical system according to any one of claims 1 to 9, wherein: The illumination optical system is an illumination optical system of a medical endoscope.

Images