Illumination optical system

Abstract

The application relates to the technical field of optical systems, in particular to an illumination optical system. The illumination optical system comprises a light source, a collimating mirror group and a double-telecentric mirror group. The light source comprises a sub-light source configured to emit a light beam. Along the light-emitting direction of the sub-light source, the collimating mirror group is located on the light-emitting side of the light source and is configured to collimate the light beam. The double-telecentric mirror group is located on the light-emitting side of the collimating mirror group and is configured to project the light beam collimated by the collimating mirror group to an image plane. The double-telecentric mirror group comprises a plurality of lenses arranged in sequence along the optical axis direction, and the optical axis direction of the double-telecentric mirror group is parallel to the light-emitting direction of the sub-light source. The application can achieve the effect of reducing energy loss while ensuring the collimated light emission of the illumination optical system through the setting of the double-telecentric mirror group.

Description

Technical Field

[0001] This application relates to the field of optical system technology, and more particularly to an illumination optical system. Background Technology

[0002] With the development of optical technology, vertical-cavity surface-emitting lasers (VCSELs) have been widely used in illumination optical systems due to their advantages such as low cost, ease of integration into two-dimensional arrays, and circular beam patterns. Currently, the high-power VCSELs commonly found on the market typically have a large divergence angle. This large divergence angle leads to a sharp decrease in far-field beam energy density and beam overlap (crosstalk), severely impacting system performance and accuracy.

[0003] In related technologies, illumination optical systems typically include a light source, a pinhole aperture array, and a collimating lens group to reduce the divergence angle. However, during use, most of the light is blocked by the pinhole aperture array, resulting in extremely low energy utilization and significant energy loss.

[0004] Therefore, there is an urgent need for an illumination optical system that can reduce energy loss while ensuring collimated light output. Summary of the Invention

[0005] This application provides an illumination optical system that, through the arrangement of a double telecentric lens group, can achieve the effect of ensuring collimated light output while reducing energy loss.

[0006] This application provides an illumination optical system, including:

[0007] A light source, which includes sub-light sources, is configured to emit light beams;

[0008] The collimating lens group is located on the light-emitting side of the light source along the light-emitting direction of the sub-light source, and the collimating lens group is configured to collimate the light beam.

[0009] The dual telecentric lens group is located on the light-emitting side of the collimating lens group and is configured to project the light beam collimated by the collimating lens group onto the image plane. The dual telecentric lens group includes multiple lenses arranged sequentially along the optical axis, and the optical axis of the dual telecentric lens group is parallel to the light-emitting direction of the sub-light source.

[0010] This application provides an illumination optical system. By positioning a collimating lens group on the light-emitting side of the light source, the beam emitted by the sub-light source directly enters the collimating lens group, which then collimates the beam. By placing a double telecentric lens group on the light-emitting side of the collimating lens group, the collimated beam directly enters the double telecentric lens group. The double telecentric lens group ensures that the collimated beam remains parallel to the optical axis. Therefore, even with an increased image-side working distance, the projected light spot on the image plane remains uniform, bright, and regularly shaped. In other words, by placing the double telecentric lens group on the light-emitting side of the collimating lens group, the image-side working distance can be increased, thereby avoiding spatial interference problems between the illumination optical system and other systems, and preventing excessive heat accumulation on the image side due to a small image-side working distance, which affects optical performance and leads to poor stability of the illumination optical system.

[0011] Furthermore, the beam is not obstructed during its transmission, resulting in extremely high energy utilization. This ensures collimated light output from the lighting optical system while reducing energy loss and significantly improving the luminous efficiency of the lighting optical system.

[0012] In some embodiments, the image-side working distance of the illumination optics system is greater than 200 mm.

[0013] In some embodiments, the total optical length of the illumination optical system is less than 500 mm.

[0014] In some embodiments, the root mean square radius of the full field of view of the illumination optics system is smaller than the Airy disk radius corresponding to the two telecentric lenses.

[0015] In some embodiments, the object-side telecentricity and image-side telecentricity of the illumination optics system are both less than 0.055°.

[0016] In some embodiments, the maximum distortion of the illumination optics system is less than 0.3%.

[0017] In some embodiments, the object-side full field of view of the illumination optics system is greater than 0 mm and less than or equal to 25 mm.

[0018] In some embodiments, the magnification of the two telecardioscopes is greater than 1.

[0019] In some embodiments, along the optical axis of the dual telecentric lens group, the plurality of lenses include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the collimating lens group to the image side;

[0020] The first, second, fifth, sixth, and seventh lenses all have positive optical power, while the third and fourth lenses all have negative optical power. The first, second, and third lenses form the front lens group, and the fourth, fifth, sixth, and seventh lenses form the rear lens group, which is a telephoto structure.

[0021] In some embodiments, the dual telecardioscope group further includes an aperture stop located at the common focal point of the anterior and posterior telescope groups.

[0022] In some embodiments, the central air gap between the first lens and the second lens is TH12, the central air gap between the second lens and the third lens is TH23, the central air gap between the third lens and the fourth lens is TH34, the central air gap between the fourth lens and the fifth lens is TH45, the central air gap between the fifth lens and the sixth lens is TH56, and the central air gap between the sixth lens and the seventh lens is TH67, wherein:

[0023] 1mm≤TH12≤2mm;

[0024] 3mm≤TH23≤3.5mm;

[0025] 61mm≤TH34≤62mm;

[0026] 4.5mm≤TH45≤5mm;

[0027] 3mm≤TH56≤3.5mm;

[0028] 9.5mm≤TH67≤10mm.

[0029] In some embodiments, the centering coefficient of the lens is greater than 0.05, and / or the lens is a spherical lens, and / or the aspect ratio and the diameter-to-edge ratio of the lens are both less than 10.

[0030] In some embodiments, the magnification of the two telecardioscopes is 1.5.

[0031] In some embodiments, the magnification of the two telecardioscopes is less than 1.

[0032] In some embodiments, along the optical axis of the dual telecentric lens group, the plurality of lenses include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the collimating lens group to the image side;

[0033] The first, second, fifth, sixth, and seventh lenses all have positive optical power, while the third and fourth lenses all have negative optical power. The first, second, and third lenses form the front lens group, and the fourth, fifth, sixth, and seventh lenses form the rear lens group, which is a telephoto structure.

[0034] The first, second, and third lenses form the front lens group, and the fourth, fifth, sixth, and seventh lenses form the rear lens group, which is a telephoto structure. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram of the structure of the illumination optical system provided for related technology 1;

[0037] Figure 2 A schematic diagram of the structure of the illumination optical system provided for related technology 2;

[0038] Figure 3 Simulated image of a collimated beam with a sub-spot size of 0-60mm in the propagation direction of an illumination optical system provided for related technology 2;

[0039] Figure 4 Simulated image of a collimated beam array spot in the propagation direction of a lighting optical system provided for related technology 2;

[0040] Figure 5 A schematic diagram of the structure of the illumination optical system provided for related technology 3;

[0041] Figure 6 A dot plot of the dual telecentric lens group of the illumination optics system provided for related technology 3;

[0042] Figure 7 MTF curve of the illumination optics system provided for related technology 3;

[0043] Figure 8 This is a schematic diagram of the structure of the illumination optical system provided in the embodiments of this application;

[0044] Figure 9 This is a schematic diagram of the overall structure of the lighting optical system provided in Embodiment 1 of this application;

[0045] Figure 10 A schematic diagram of the 1.5x dual telecentric lens assembly structure of the illumination optical system provided in Embodiment 1 of this application;

[0046] Figure 11 MTF curve of the 1.5x double telecentric lens group of the illumination optics system provided in Embodiment 1 of this application;

[0047] Figure 12 A dot plot of the 1.5x double telecentric lens group for the illumination optical system provided in Embodiment 1 of this application;

[0048] Figure 13 Distortion curve of the 1.5x double telecentric lens group of the illumination optical system provided in Embodiment 1 of this application;

[0049] Figure 14 A simulation diagram of the light surface distribution of the VCSEL array sub-light source in the illumination optical system provided in Embodiment 1 of this application at different locations in the system;

[0050] Figure 15 A simulation diagram of the angular distribution of light rays at different locations in the VCSEL array sub-light source of the illumination optical system provided in Embodiment 1 of this application;

[0051] Figure 16 A simulation diagram of the light surface distribution of the VCSEL array light source in the illumination optical system provided in Embodiment 1 of this application at the rear surface of the microlens array and the image plane position;

[0052] Figure 17 This is a schematic diagram of the overall structure of the lighting optical system provided in Embodiment 2 of this application;

[0053] Figure 18 A schematic diagram of the 0.6x dual telecentric lens assembly structure of the illumination optical system provided in Embodiment 2 of this application;

[0054] Figure 19 MTF curve of the 0.6x double telecentric lens group of the illumination optics system provided in Embodiment 2 of this application;

[0055] Figure 20 A dot plot of the 0.6x double telecentric lens group of the illumination optical system provided in Embodiment 2 of this application;

[0056] Figure 21 The distortion curve of the 0.6x dual telecentric lens group of the illumination optical system provided in Embodiment 2 of this application;

[0057] Figure 22 A simulation diagram of the light surface distribution of the VCSEL array light source in the illumination optical system provided in Embodiment 2 of this application at the rear surface of the microlens array and the image plane position;

[0058] Figure 23 This is a schematic diagram of the dual telecentric lens group used for adjusting the surface diameter and divergence angle of the lighting optical system provided in Embodiment 3 of this application.

[0059] Figure label:

[0060] 10-Bilateral distal cardiac endoscopic group;

[0061] 11-Lens; 11a-Anterior end face; 11b-Rear end face;

[0062] 111 - First Lens;

[0063] 112 - Second lens;

[0064] 113 - Third lens;

[0065] 114 - Fourth Lens;

[0066] 115 - Fifth Lens;

[0067] 116 - Sixth lens;

[0068] 117 - Seventh Lens;

[0069] 20-Object Square;

[0070] 21-Light source;

[0071] 22 - Collimating lens group; 221 - Front surface; 222 - Rear surface;

[0072] 23a - Small aperture array;

[0073] 24a - Aperture stop;

[0074] 30-Image Square. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0076] To facilitate understanding, the relevant technical terms involved in the embodiments of this application will first be explained and described.

[0077] Numerical aperture (NA) is a physical quantity that characterizes the light-gathering ability and spatial resolution of an optical system (such as a lens, fiber optic cable, or microscope objective).

[0078] Focal length, also known as focal length, is a measure in optical systems of the convergence or divergence of light. It refers to the perpendicular distance from the optical center of a lens or lens group to the focal plane when a distant object is projected into a sharp image on the focal plane. From a practical perspective, it can be understood as the distance from the center of the lens (lens assembly) to the image plane.

[0079] The optical axis refers to the straight line that passes through the center of each lens element in a lens assembly.

[0080] Optical power is the ability of a lens to refract a parallel beam of light incident on the ground; it is also called refractive power.

[0081] Positive focal length means that the lens has a positive focal length and has the effect of converging light.

[0082] Negative power means that the lens has a negative focal length, which has the effect of diverging light.

[0083] The field of view (FOV) is the angle between the two edges of the lens assembly, which is the maximum range through which the image of the subject can pass through the lens assembly, with the lens assembly as the vertex.

[0084] The object side, also known as the object side, is the side where the subject is located, with the lens assembly as the boundary. The side of the lens in the lens assembly that faces the object side is the object side of the lens.

[0085] The image side, also known as the image plane, is the side where the image of the subject is located, with the lens assembly as the boundary. The side of the lens in the lens assembly that faces the image side is the image plane of the lens.

[0086] Image height (IH), also known as holographic height, refers to the height of the holographic image formed by the lens assembly.

[0087] The image plane, defined by the lens assembly, is the plane in the image space where the converged light beams from the lens assembly form a sharp image of the subject. The image plane typically coincides with the target surface of the image sensor.

[0088] The principal plane of an image refers to the virtual plane perpendicular to the optical axis formed by the intersection of the backward extension of the outgoing ray and the extension of the incident ray after refraction by an optical system.

[0089] The focal point is the point where the outgoing ray (or its backward extension) of an incident ray parallel to the optical axis intersects the optical axis after refraction by the optical system.

[0090] Aberration refers to the deviation between the image formed on the image plane and the ideal image of the subject object, caused by limitations in lens material, surface shape, and optical design in an optical system.

[0091] Object-side telecentricity refers to the degree of parallelism between the principal ray and the optical axis on the light source side (object side) of a lighting system.

[0092] Image-side telecentricity refers to the degree of parallelism between the principal ray and the optical axis on the target side (image side) of the illumination system.

[0093] Reverse telephoto configuration is an optical lens design that typically consists of a front negative lens and a rear positive lens, characterized by a longer back working distance and a wide field of view.

[0094] The root mean square (RMS) radius across the entire field of view is a core parameter used to comprehensively evaluate the imaging quality or spot concentration of an optical system (lens or lens group). It quantitatively describes the degree to which light deviates from the ideal imaging point due to various aberrations. The RMS radius across the entire field of view is usually compared with the Airy disk radius (the theoretical minimum radius of the spot at the diffraction limit). If the RMS radius is close to or smaller than the Airy disk radius, it indicates that the system's aberrations are well controlled and close to the diffraction limit.

[0095] The Airy disk radius refers to the theoretical minimum radius of the light spot under the diffraction limit.

[0096] The Modulation Transfer Function (MTF) measures the degree of "blurring" of black and white lines after they are imaged through a lens. An ideal lens (MTF=1) can maintain 100% of the original contrast; a poor lens (MTF close to 0) will make black and white lines completely blurred into a gray area. The MTF value is always between 0 and 1, and the closer it is to 1, the higher the resolution.

[0097] Image-side working distance refers to the axial distance from the mechanical flange face or outer surface vertex of the image side (i.e., the side from which light is emitted) of the last optical element (usually a lens or objective lens) of the illumination system to the target plane (such as the sample surface or pupil surface) that is uniformly illuminated.

[0098] The aperture of a light source refers to the size of the light spot that is considered as an "object" and fed into the first lens unit of a microlens array during optical design.

[0099] The centering coefficient is a core indicator for measuring the installation accuracy of a lens (lens) within the lens barrel. It comprehensively reflects the eccentricity (translation) and tilting errors caused by lens installation, quantitatively describes the degree of deviation between the actual optical axis and the theoretical assembly reference axis, and directly predicts the impact of this deviation on the deterioration of the final image quality.

[0100] Abbe number is a numerical indicator that measures the "resistance to chromatic aberration" of an optical material. The Abbe number of a lens is a core physical parameter describing the dispersion characteristics of optical glass materials; it quantifies the material's tendency to cause chromatic aberration (color blurring). The lower the Abbe number, the more severe the dispersion; the higher the Abbe number, the less severe the dispersion.

[0101] The radius of curvature to diameter ratio refers to the ratio of the radius of curvature R to the lens diameter D.

[0102] A collimating lens group refers to an optical system that converts diverging light beams into parallel light beams.

[0103] A double telecentric lens refers to a specially designed imaging lens in which the principal rays of both the object and image sides are parallel to the optical axis.

[0104] With the development of optical technology, lighting optical systems are commonly used in precision optical inspection, industrial laser light sources, biomedical imaging, lidar, and 3D imaging and structured light projection.

[0105] In the above scenario, vertical cavity surface-emitting lasers (VCSELs) are widely used as light sources due to their advantages such as low cost, ease of integration into two-dimensional arrays, and circular light spots.

[0106] However, the divergence angle of the emitted beam from commonly available high-power VCSEL lasers is relatively large (usually exceeding 20°). When VCSEL light source arrays are used for long-distance illumination or precision applications requiring uniform beams and sharp edges (such as optical inspection and high-precision measurement), the large divergence angle leads to a sharp decrease in the energy density of the far-field beam and beam overlap (crosstalk) between beams, which seriously affects the performance and accuracy of the system.

[0107] To solve the above problems and enable the beam to be collimated and emitted, see [reference needed]. Figure 1 In related technology 1, the illumination optical system includes a light source 21a, a pinhole aperture array 23a, and a collimating lens group 22a. The light source 21a emits light, which diffuses in all directions and passes through the pinhole aperture array 23a to form a point light source 21a. Subsequently, the point light source 21a is collimated and emitted through the collimating lens group 22a.

[0108] However, in this process, only a small portion of the light can pass through the pinhole aperture array 23a to form a point light source 21a, while most of the light is blocked by the pinhole aperture array 23a, resulting in extremely low energy utilization and serious energy loss. This significantly affects the luminous efficiency of the entire lighting optical system and may not meet the requirements of scenarios with high light power density.

[0109] See Figure 2 , Figure 3 and Figure 4 In related technology 2, the illumination optical system includes a light source 21b, a collimating lens group 22b, and a double telecentric lens group 10b. The double telecentric lens group 10b is located between the light source 21b and the collimating lens group 22b. The light source 21b emits light, which is first projected onto the collimating lens group 22b via the double telecentric lens group 10b, then collimated by the collimating lens group 22b, and finally emitted.

[0110] However, in this process, the collimating light is only collimated by the collimating lens group 22b, and the collimated light source 21b still has a certain divergence angle.

[0111] For example, the sub-light source has an aperture of 0.5 mm, a divergence half-angle of 0.3°, and a center-to-center spacing of 0.75 mm. Figure 3 This is a simulation diagram of the sub-spot of the sub-source within the propagation direction of 0-60mm. Figure 4 This is a simulation diagram of a collimated beam array spot in the propagation direction of a 60mm array.

[0112] according to Figure 3 and Figure 4 Simulation results show that as the light propagation distance increases, the sub-spot diameter gradually increases, while its edges gradually become blurred. Furthermore, at 60 mm, the spot diameter exceeds the center-to-center spacing between the 21 light sources, indicating crosstalk.

[0113] Therefore, in order to ensure the quality of the light spot, it is necessary to reduce the working distance of the image side.

[0114] However, a small image-side working distance can easily lead to spatial interference between the illumination optics system and other systems. Furthermore, without proper heat dissipation, a small image-side working distance can cause excessive heat accumulation, affecting optical performance and resulting in poor stability of the illumination optics system.

[0115] Meanwhile, in related technology 2, it is necessary to align and assemble the light source 21b with the double telecentric lens group 10b, and align and assemble the double telecentric lens group 10b with the collimating lens group 22b, which is a complex process. If there is an error in the alignment and assembly of the light source 21b and the double telecentric lens group 10b, the error will be transmitted to the collimating lens group 22b with high tolerance sensitivity, resulting in a decrease in the collimation capability of the illumination optical system.

[0116] Furthermore, when the double telecentric lens group 10b is placed behind the light source 21b, the divergence angle of the beam is large, resulting in a large Nb value. This requires the double telecentric lens group 10b to be designed for a large object square Nb. The structural design complexity of the double telecentric lens group 10b, which takes into account both a large object square field of view and excellent performance, is significantly increased, which is not conducive to manufacturing.

[0117] See Figure 5 and Figure 6 In related technology 3, the illumination optical system includes a group of 6 symmetrical double telecentric lenses 10. The object-side NA is 0.18, corresponding to a full beam divergence angle of 20.8°, and the object-side full field of view is 1.8 mm. The system controls the object-side and image-side telecentricity within ±0.5 degrees.

[0118] Due to the small object-side viewing angle, the illumination optical system in related technology 3 is only suitable for imaging small-sized arrays. The system is designed with an object height of only 0.9 mm, which is only applicable to imaging scenarios with a small number of array light sources 21. As the array size increases, its imaging performance will be significantly affected.

[0119] Figure 5 This is a schematic diagram of the illumination optical system structure of related technology 3. Figure 6 A dot plot of the dual telecardioscope group for the illumination optics system provided in related technology 3. Figure 7 The MTF curve is for the illumination optical system of related technology 3.

[0120] See Figure 6 The system does not optimize all light rays to fall within the Airy ring; see [link / reference]. Figure 7 The system has not yet been optimized to the diffraction limit, resulting in poor imaging resolution and blurry, unclear edges of the light spot.

[0121] In summary, although the relevant lighting optical systems are combined with various optical components to achieve better collimation, problems such as small image working distance, poor spot quality, and low light energy utilization still exist.

[0122] Therefore, how to ensure collimated light output from the lighting optical system while minimizing the image working distance, improving the light spot quality, and increasing the light energy utilization rate has become a problem to be solved.

[0123] In view of this, this application provides an illumination optical system. By placing a double telecentric lens group 10 on the light-emitting side of the collimating lens group 22, the collimated beam directly enters the double telecentric lens group 10. The double telecentric lens group 10 ensures that the collimated beam remains parallel to the optical axis, so that even when the image-side working distance increases, the light spot projected onto the image plane remains uniform, bright, and regularly shaped, resulting in high quality. By increasing the image-side working distance, spatial interference problems between the illumination optical system and other systems can be avoided, as well as the problem of excessive heat accumulation on the image side 30 due to a small image-side working distance, which affects optical performance and leads to poor stability of the illumination optical system. Furthermore, during the beam transmission process, the beam is not obstructed, resulting in extremely high energy utilization. While ensuring collimated light output from the illumination optical system, energy loss is reduced, significantly improving the luminous efficiency of the illumination optical system.

[0124] See Figure 8 This application provides an illumination optical system, including a light source 21, a collimating lens group 22, and a double telecentric lens group 10.

[0125] Light source 21 includes sub-light sources, which are configured to emit beams.

[0126] Along the light-emitting direction of the sub-light source, the collimating lens group 22 is located on the light-emitting side of the light source 21, and the collimating lens group 22 is configured to collimate the light beam.

[0127] The dual telecentric lens group 10 is located on the light-emitting side of the collimating lens group 22 and is configured to project the light beam collimated by the collimating lens group 22 onto the image plane. The dual telecentric lens group 10 includes a plurality of lenses 11 arranged sequentially along the optical axis, and the optical axis of the dual telecentric lens group 10 is parallel to the light-emitting direction of the sub-light source.

[0128] During operation, light source 21 emits sub-light sources, each of which is independently configured to emit a beam. These initial beams have a certain divergence angle. The beams first propagate to collimating lens group 22 located on the light-emitting side of light source 21. Collimating lens group 22 receives the beam and collimates it, reducing the divergence angle of the beam so that the propagation direction of the light becomes parallel to the optical axis, thereby outputting a collimated beam.

[0129] The collimating lens group 22 can be a microlens group, which includes multiple microlenses. Each microlens is aligned with a sub-light source and is used to independently collimate the beam emitted by that sub-light source, thereby improving the collimation effect of the collimating lens group 22.

[0130] Subsequently, the collimated beam enters the double telecentric lens group 10 located on the light-emitting side of the collimating lens group 22. The collimated beam enters from the front end surface 11a of the lens 11 of the double telecentric lens group 10 and exits from the rear end surface 11b. The double telecentric lens group 10 transmits the received collimated beam and finally projects it onto the image plane. In this process, through the telecentricity of the object side 20 and the image side 30 of the double telecentric lens group 10, the double telecentric lens group 10 can ensure that the collimated beam remains parallel to the optical axis, thereby forming a uniform, bright, and regularly shaped light spot, ensuring a stable and uniform illumination effect, and significantly reducing optical distortion.

[0131] Since the dual telecentric lens group 10 receives a collimated beam, the divergence angle of the collimated beam is compressed, and the dual telecentric lens group 10 can ensure that the collimated beam remains parallel to the optical axis. Therefore, when the image-side working distance increases, the light spot projected onto the image plane remains uniform, bright, and regularly shaped, thus improving the quality of the light spot. This also enables the illumination optical system provided in this application to increase the image-side working distance, thereby avoiding spatial interference problems between the illumination optical system and other systems, as well as the problem of excessive heat accumulation on the image side 30 due to a small image-side working distance, which affects optical performance and leads to poor stability of the illumination optical system.

[0132] Simultaneously, the divergence angle is compressed, resulting in a smaller object-side NA (NA), which allows the illumination optical system provided in this application to utilize a dual-distance lens group with a small object-side NA value. This dual-distance lens group with a small object-side NA value features a simple spacing structure, a large field of view, and low distortion, effectively improving the field of view and output beam performance of the illumination optical system.

[0133] Furthermore, the collimating lens group 22 is located on the light-emitting side of the light source 21, allowing for direct integration with the light-emitting side of the light source 21, for example, through physical contact or optical adhesive bonding. This design offers high alignment accuracy and mature technology, reducing assembly errors and thus improving the collimation capability of the lighting optical system. During beam transmission, the beam is not obstructed, resulting in extremely high energy utilization. While ensuring collimated light output from the lighting optical system, energy loss is reduced, significantly improving the luminous efficiency of the lighting optical system.

[0134] This application provides an illumination optical system. By positioning the collimating lens group 22 on the light-emitting side of the light source 21, the light beam emitted by the sub-light source directly enters the collimating lens group 22, which then collimates the beam. By placing the double telecentric lens group 10 on the light-emitting side of the collimating lens group 22, the collimated beam directly enters the double telecentric lens group 10. The double telecentric lens group 10 ensures that the collimated beam remains parallel to the optical axis. Therefore, even when the image-side working distance increases, the light spot projected onto the image plane remains uniform, bright, and regularly shaped. In other words, by placing the double telecentric lens group 10 on the light-emitting side of the collimating lens group 22, the image-side working distance can be increased, thereby avoiding spatial interference problems between the illumination optical system and other systems, and preventing excessive heat accumulation on the image side 30 due to a small image-side working distance, which affects optical performance and leads to poor stability of the illumination optical system.

[0135] Furthermore, the beam is not obstructed during its transmission, resulting in extremely high energy utilization. This ensures collimated light output from the lighting optical system while reducing energy loss and significantly improving the luminous efficiency of the lighting optical system.

[0136] In some embodiments, the image-side working distance of the illumination optics system is greater than 200 mm.

[0137] Specifically, along the optical axis, the distance from the lens 11 closest to the image plane in the double telecentric lens group 10 to the image plane is designed to be greater than 200mm.

[0138] When the image-side working distance is greater than 200mm, the illumination optical system can ensure that all sub-light sources can achieve high-precision collimation output, while also allowing other optical components, mechanical structures, or sufficient operating space to be installed near the image plane. This avoids spatial interference between the illumination optical system and other systems, as well as the problem of excessive heat accumulation on the image plane due to the small image-side working distance, which affects optical performance and leads to poor stability of the illumination optical system.

[0139] In some embodiments, the total optical length of the illumination optical system is less than 500 mm.

[0140] Specifically, the distance between the light source 21 and the image plane is less than 500mm. This design makes the structure of the lighting optical system compact, greatly saves the installation space of the lighting optical system, reduces the size and weight of the lighting optical system, improves the portability and integration of the lighting optical system, and enhances the applicability of the lighting optical system.

[0141] For example, the total length of the illumination optical system is 450mm and the image-side working distance is 285mm. This ensures that the image-side working distance is increased while making the illumination optical system structure compact, achieving system miniaturization. In turn, while ensuring that the light spot remains uniform, bright and regular in shape, the system performance and size are optimized and balanced.

[0142] In some embodiments, the root mean square radius of the full field of view of the illumination optics system is smaller than the Airy disk radius corresponding to the double telecentric lens group 10.

[0143] By setting up the light source 21, the collimating lens group 22 and the double telecentric lens group 10, the light spot diffusion is suppressed, so that in the entire illumination field of view, the main factor determining the light spot size is no longer geometric aberration, but the diffraction limit determined by the aperture of the optical system.

[0144] Specifically, when the root mean square radius of the full field of view of the illumination optical system is smaller than the Airy disk radius corresponding to the double telecentric lens group 10, the imaging quality of the illumination optical system approaches the diffraction limit, and the aberration is well controlled, thereby ensuring that the illumination spot is not only uniform and sharp, but also has extremely high energy concentration and theoretical resolution.

[0145] In some embodiments, the object-side telecentricity and image-side telecentricity of the illumination optics system are both less than 0.055°.

[0146] With both the object-side and image-side telecentricities of the illumination optics system being less than 0.055°, the propagation angle of the light beam can be constrained. Specifically, an object-side telecentricity of less than 0.055° ensures that the light beam entering the collimating lens group 22 is parallel to the optical axis, which is a prerequisite for achieving low-distortion and high-uniformity imaging. An image-side telecentricity of less than 0.055° ensures that when the light beam transmitted through the double telecentric lens group 10 reaches the image plane, the beam at each point is nearly perpendicularly incident, thereby ensuring the formation of a uniform, bright, and regularly shaped light spot with low distortion.

[0147] In some embodiments, the maximum distortion of the illumination optics system is less than 0.3%.

[0148] During operation, light source 21 emits a sub-light source, which emits a beam. This beam is collimated by collimating lens group 22 and then enters the double telecentric lens group 10 for transmission and imaging. The double telecentric lens group 10, as the core component for controlling distortion, minimizes the deviation between the actual imaging height and the theoretical ideal imaging height of the principal rays emitted from all object points after passing through it. By controlling the maximum value of this relative deviation—the maximum distortion—at all field-of-view positions, ensuring its absolute value is less than 0.3%, the illumination optical system achieves highly faithful transmission of geometry throughout the entire illumination area.

[0149] In some embodiments, the object-side full field of view of the illumination optics system is greater than 0 mm and less than or equal to 25 mm.

[0150] Compared to related technology 3, the object-side full field of view of the illumination optical system provided in this application embodiment can reach 25mm. Within the range of object-side full field of view greater than 0mm and less than or equal to 25mm, the sub-light sources can all achieve high-precision collimation output, meeting the collimation and modulation requirements of the large-size light source 21.

[0151] In some embodiments, the magnification of the bilateral telecardioscope group 10 is greater than 1. For ease of description, the bilateral telecardioscope group 10 with a magnification greater than 1 is referred to as the first type of bilateral telecardioscope group.

[0152] Since the magnification of the first type of telecentric lens group is greater than 1, the first type of telecentric lens group not only performs the core functions of telecentric imaging and controlling the collimation beam angle, but also can magnify and image the beam incident on the first type of telecentric lens group.

[0153] Specifically, the beam collimated by the collimating lens group 22 enters a first type of telecentric lens group with a magnification greater than 1. The lens 11 on the object side 20 of the first type of telecentric lens group first ensures that the incident beam is parallel to the optical axis. Then, the beam passes through the lens 11 with a specific optical power distribution inside the first type of telecentric lens group, and the beam aperture is gradually expanded and transmitted. Finally, the lens 11 on the image side 30 of the first type of telecentric lens group projects the magnified beam onto the image plane in a direction parallel to the optical axis.

[0154] In the process, the first type of double telecentric lens group with a magnification greater than 1 can further compress the divergence angle of the beam, thereby achieving a second collimation of the beam after it has been collimated by the collimating lens group 22, thus improving the collimation effect of the illumination optical system.

[0155] Furthermore, when the magnification of the first type of telecentric lens group is greater than 1, the larger the magnification of the first type of telecentric lens group, the better the compression effect on the divergence angle of the beam, and thus the better the collimation effect of the beam and the better the collimation effect of the illumination optical system.

[0156] By setting the magnification of the first type of double telecentric lens group to be greater than 1, the first type of double telecentric lens group can further compress the divergence angle of the collimated beam after passing through the collimating lens group 22 and magnify the projection, thereby expanding the small diameter light source 21 into a large area of ​​uniform illumination. Thus, the need for large-area illumination can be met without using a large-size light source 21, which is conducive to the miniaturization and modular design of the system.

[0157] In some embodiments, along the optical axis of the first type of telecentric lens group, the plurality of lenses 11 include a first lens 111, a second lens 112, a third lens 113, a fourth lens 114, a fifth lens 115, a sixth lens 116 and a seventh lens 117 arranged sequentially from the collimating lens group 22 to the image side.

[0158] The first lens 111, the second lens 112, the fifth lens 115, the sixth lens 116, and the seventh lens 117 all have positive optical power, while the third lens 113 and the fourth lens 114 both have negative optical power. The first lens 111, the second lens 112, and the third lens 113 form the front lens group, and the fourth lens 114, the fifth lens 115, the sixth lens 116, and the seventh lens 117 form the rear lens group, which is a telephoto structure.

[0159] During operation, the collimated beam from the collimating lens group 22 first converges through the first lens 111 and the second lens 112, which have positive optical power. Subsequently, the beam passes through the third lens 113, which has negative optical power, and its diverging effect begins to adjust the convergence state of the beam and correct some of the aberrations generated in the early stage.

[0160] Subsequently, the light beam enters the rear lens group: first, it passes through the fourth lens 114, which has negative optical power, further diverging the beam and laying the foundation for extending the rear working distance. Then, the beam sequentially passes through the fifth lens 115, sixth lens 116, and seventh lens 117, which have positive optical power. These lenses work together to refocus and collimate the beam, accurately projecting it onto the image plane. The rear lens group is a reverse telephoto structure, which helps to maintain a short focal length while achieving a longer rear working distance.

[0161] The rear lens group consists of a lens 11 with positive optical power and a lens 11 with positive optical power, forming a reverse telephoto structure, which helps to maintain a short focal length while having a longer image-side working distance.

[0162] Both the front and rear lens groups have lenses 11 with positive optical power, which helps to reduce telecentricity and higher aberrations and improve illumination quality.

[0163] In some embodiments, the first dual telecardiogram group further includes an aperture stop 24a, which is located at the common focal point of the anterior and posterior telecardiogram groups.

[0164] During operation, the light beam originating from the collimating lens group 22, which has already achieved a certain degree of collimation, first enters the front lens group, which consists of the first lens 111, the second lens 112, and the third lens 113. As a complete optical subsystem, the front lens group's image-side focal point coincides with the plane of the aperture stop 24a. Therefore, any light beam emitted from any point in the object-side field of view, after being converged by the front lens group, will pass through the image-side focal point of the front lens group and then through the aperture stop 24a.

[0165] These beams then enter the rear mirror group, which consists of the fourth lens 114, the fifth lens 115, the sixth lens 116, and the seventh lens 117. Since the aperture stop 24a is also located at the object-side focal point of the rear mirror group, according to the principle of optical path reversibility, the light rays passing through the aperture stop 24a, after being refracted by the rear mirror group, will have their outgoing principal rays parallel to the optical axis of the illumination optical system.

[0166] The design of aperture stop 24a ensures that the beams of the sub-light sources are projected at the same angle, thereby achieving high uniformity and precision of the illumination field.

[0167] In some embodiments, the central air gap between the first lens 111 and the second lens 112 is TH12, the central air gap between the second lens 112 and the third lens 113 is TH23, the central air gap between the third lens 113 and the fourth lens 114 is TH34, the central air gap between the fourth lens 114 and the fifth lens 115 is TH45, the central air gap between the fifth lens 115 and the sixth lens 116 is TH56, and the central air gap between the sixth lens 116 and the seventh lens 117 is TH67, wherein:

[0168] 1mm≤TH12≤2mm;

[0169] 3mm≤TH23≤3.5mm;

[0170] 61mm≤TH34≤62mm;

[0171] 4.5mm≤TH45≤5mm;

[0172] 3mm≤TH56≤3.5mm;

[0173] 9.5mm≤TH67≤10mm.

[0174] When the above conditions are met, the total optical length (TTL) of the dual telecentric lens can be guaranteed to be: TTL≤500mm, thus achieving a compact structure.

[0175] In some embodiments, the centering coefficient of lens 11 is greater than 0.05, and / or lens 11 is a spherical lens, and / or the aspect ratio and the diameter-to-edge ratio of lens 11 are both less than 10.

[0176] By having a centering coefficient greater than 0.05, the sensitivity of lens 11 to assembly tilt can be reduced, thereby reducing the assembly difficulty.

[0177] For example, the first lens 111, the second lens 112, the fourth lens 114, the fifth lens 115, and the sixth lens 116 are meniscus lenses, the third lens 113 is a biconcave lens, and the seventh lens 117 is a biconvex lens. Each lens 11 is a spherical mirror. By rationally setting the surface shape of each lens and appropriately allocating the optical power, smooth edge light paths can be ensured, improving illumination uniformity.

[0178] With the aspect ratio and edge ratio of lens 11 both less than 10, the structure of lens 11 is stable and it is not easy to deform during assembly and use.

[0179] In some embodiments, the magnification of the first bicentroscopic group is 1.5.

[0180] For example, the magnification of the first dual telecentric lens group is 1.5. Wherein, F1 / F2≈-1.5, F1 is the focal length of the front lens group, and F2 is the focal length of the rear lens group. The focal length constraint between the front and rear groups can effectively ensure a magnification of 1.5 times, thereby improving the illumination quality.

[0181] It should be noted that this application does not impose further restrictions on the parameters, quantity, and arrangement of the light source 21d, the type of microlens array (spherical, aspherical, freeform, etc.), or the magnification and configuration of the first type of telecentric lens group; it only needs to meet the requirements of the illumination optical system.

[0182] Example 1

[0183] The illumination optical system provided in this embodiment 1 includes a light source 21d, a collimating lens group 22d, and a double telecentric lens group 10d. Among them, the light source 21d is a VCSEL light source array, the collimating lens group 22d is an aspherical microlens array, and the double telecentric lens group 10d is a first type of double telecentric lens group.

[0184] In Example 1, the illumination optical system is described using the first type of telecardiogram group, which is a 7-piece 1.5x telecardiogram group.

[0185] The VCSEL light source array consists of sub-light sources arranged in an array with a wavelength of 850nm. The lenses in the microlens array adopt a plano-convex lens structure with a thickness of 0.3mm at the center of the optical axis. The front surface 221 is flat, the radius of curvature of the rear surface 222 is -0.633mm, the conicity is -0.617, and the selected material has a refractive index of 1.69 and an Abbe number of 53.1.

[0186] The structure of the 10-day bipolar endocardiogram group is as follows: Figure 10 As shown, the object plane is the rear surface 222 of the microlens array. The specific structural parameters are shown in Table 1. All 7 lenses 11 are spherical mirrors. The glass material is selected from high-frequency production materials of Chengdu Guangming, with grades H-ZF4A, H-LAK52, H-ZF88, and H-ZPK5.

[0187] Table 1. Specific parameters of the 1.5x telecardiography group in Example 1

[0188]

[0189] It should be noted that lens spacing refers to the air gap between two adjacent lenses 11 in the bipolar telecardiogram group on opposite sides. For example, the lens spacing of 1.60 corresponding to the first lens 111a in Table 1 can be understood as the central air gap TH12 between the first lens 111a and the second lens 112a being 1.60. Similarly, the lens spacing of 3.26 corresponding to the second lens 112a can be understood as the central air gap TH23 between the second lens 112a and the third lens 113a being 3.26, and so on. The lens spacings in Table 1 will not be explained individually again.

[0190] The dual telecentric lens has a 10d magnification of 1.5x, a total length of 450mm, an image-side working distance of 285mm, an object-side full field of view of 25mm, an object-side NA of 0.02, an object-side telecentricity of less than 0.055°, and a maximum distortion of less than 0.3%.

[0191] A VCSEL light source array emits a beam of light, which is then collimated by an aspherical microlens array. The collimated beam then enters a 7-element 1.5x telecardioscope assembly. The 7-element 1.5x telecardioscope assembly transmits and magnifies the beam for projection.

[0192] Specifically, the light beam originating from the collimating lens group 22d, which already possesses a certain degree of collimation, first enters the front mirror group, which consists of the first lens 111a, the second lens 112a, and the third lens 113a. As a complete optical subsystem, the image-side focal point of the front mirror group coincides with the plane of the aperture stop 24a. Therefore, light beams emanating from any point in the object-side field of view, after being converged by the front mirror group, will pass through the image-side focal point of the front mirror group and then through the aperture stop 24a. These light beams then enter the rear mirror group, which consists of the fourth lens 114a, the fifth lens 115a, the sixth lens 116a, and the seventh lens 117a. After refraction by the rear mirror group, they exit.

[0193] Figures 9-16 This is the first image for evaluating the pixel quality of the dual telecardiogram group. Figure 11 For the modulation transfer function curve of the first type of dual telecardiography group, see [link / reference]. Figure 11 The MTF values ​​are all greater than 0.3@16lp / mm, and the MTF curves across the entire field of view are close to the diffraction limit. Figure 12 For the first type of bilateral distal cardiac endoscopic group dot plot, see [link / reference]. Figure 12 The full-field RMS radius is smaller than the Airy disk radius, and the first type of dual telecardioscope produces images of good quality. Figure 13 For the first type of bidistal cardiac endoscopic distortion curve, see [link / reference]. Figure 13 The distortion level is less than 0.3%.

[0194] The manufacturability evaluation parameters of each lens 11 in the first type of telecardioscope group are shown in Table 2. The centering coefficient is >0.05, the radius of curvature to diameter ratio is >0.8, and the diameter-to-thickness ratio and diameter-to-edge ratio are both <10. These parameters ensure that the first type of telecardioscope group has excellent manufacturability.

[0195] Table 2. Manufacturability evaluation parameters of the 1.5x bi-telecardiography group in Example 1

[0196]

[0197] Figure 14 , Figure 15 The surface and angular distribution of light rays from the VCSEL sub-source in the illumination optical system are presented at the light exit aperture, at the rear surface 222 of the microlens array, and at the system image plane. The sub-source has a light exit aperture of 10 μm and a divergence angle of 30°. After being collimated by the aspherical microlens array, the beam diameter of the sub-source is expanded to 0.49 mm, while the beam divergence angle is effectively compressed to 0.62°. After being magnified and projected by the first type of double telecentric lens group, the sub-spot diameter on the image plane is 0.74 mm, and the divergence angle is 0.42°.

[0198] Figure 16 The distribution of light spots on the light-emitting surface and image plane array of the illumination optical system was investigated under the condition that 400 sub-light sources with a spacing of 0.75 mm were arranged in a 20×20 matrix. The light from the light-emitting surface array was uniformly magnified and projected onto the image plane. The light spot distribution on the image plane was uniform, with no crosstalk distortion. The light power on the light-emitting surface was 0.6968 W, and the light power on the image plane was 0.6866 W. The system luminous efficacy reached 98.54%.

[0199] This application effectively improves the system's object-side field of view and output beam quality. While effectively compressing the divergence angle, it limits the 21d surface diameter of the light source. The system has the advantages of high image quality output and strong manufacturability, and can better adapt to the collimation dot matrix illumination requirements of large-size VCSEL light source arrays. The long image-side working distance effectively avoids spatial interference with other systems and heat accumulation on the imaging surface, improving the system's applicability. It can simultaneously meet the needs of various laser application scenarios with multiple light source 21d parameter arrangement types and multiple illumination requirements, and improves the applicability of lasers in long-distance sensing, laser precision measurement, and uniform dot matrix illumination scenarios.

[0200] In some embodiments, the magnification of the bidiscocardiography group 10d is less than 1. For ease of description, the bidiscocardiography group 10d with a magnification of less than 1 is referred to as the second type of bidiscocardiography group.

[0201] Since the magnification of the second type of telecentric lens group is less than 1, the second type of telecentric lens group can reduce the beam cross section and project it onto the image plane while maintaining the telecentric characteristics of the object and image.

[0202] Specifically, the light beam, collimated by the collimating lens group 22, enters a second type of telecentric lens group with a magnification of less than 1. The lens 11 on the object side 20 of the second type of telecentric lens group first ensures that the incident light beam is parallel to the optical axis. Then, the light beam passes through the lens 11 with a specific optical power distribution within the second type of telecentric lens group, and the beam cross-section is gradually reduced and transmitted. Finally, the lens 11 on the image side 30 of the second type of telecentric lens group projects the reduced light beam onto the image plane in a direction parallel to the optical axis.

[0203] Throughout the process, the second type of double telecentric lens group with a magnification of less than 1 does not further compress the divergence angle of the beam, but only reduces the beam cross-section.

[0204] By setting the magnification of the second type of telecentric lens group to be less than 1, the second type of telecentric lens group can reduce the projection of the collimated beam after passing through the collimating lens group 22, thereby reducing the large diameter light source 21 into a smaller area of ​​uniform illumination, making it suitable for occasions with higher requirements for illumination density.

[0205] In some embodiments, along the optical axis of the second type of telecentric lens group, the plurality of lenses 11 include a first lens 111, a second lens 112, a third lens 113, a fourth lens 114, a fifth lens 115, a sixth lens 116 and a seventh lens 117 arranged sequentially from the collimating lens group 22 to the image side.

[0206] The first lens 111, the second lens 112, the fifth lens 115, the sixth lens 116, and the seventh lens 117 all have positive optical power, while the third lens 113 and the fourth lens 114 both have negative optical power. The first lens 111, the second lens 112, and the third lens 113 form the front lens group, and the fourth lens 114, the fifth lens 115, the sixth lens 116, and the seventh lens 117 form the rear lens group, which is a telephoto structure.

[0207] The first lens 111, the second lens 112 and the third lens 113 form the front lens group, and the fourth lens 114, the fifth lens 115, the sixth lens 116 and the seventh lens 117 form the rear lens group, which is a telephoto structure.

[0208] The rear lens group consists of a lens with positive optical power and a lens with positive optical power, forming a reverse telephoto structure, which helps to maintain a short focal length while having a longer image-side working distance.

[0209] Both the front and rear lens groups contain lenses with positive optical power, which helps reduce telecentricity and higher aberrations, thus improving illumination quality.

[0210] For example, the magnification of the second type of dual telecardioscope group is 0.6. Wherein, F1 / F2≈0.6, F1 is the focal length of the front lens group, and F2 is the focal length of the rear lens group. The focal length constraint between the front and rear groups can effectively ensure a magnification of 0.6 times.

[0211] Wherein, the center air gap between the first lens 111 and the second lens 112 is TH12, the center air gap between the second lens 112 and the third lens 113 is TH23, the center air gap between the third lens 113 and the fourth lens 114 is TH34, the center air gap between the fourth lens 114 and the fifth lens 115 is TH45, the center air gap between the fifth lens 115 and the sixth lens 116 is TH56, and the center air gap between the sixth lens 116 and the seventh lens 117 is TH67.

[0212] 11.5mm≤TH12≤12mm;

[0213] 9.5mm≤TH23≤10mm;

[0214] 138mm≤TH34≤139mm;

[0215] 6.5mm≤TH45≤7mm;

[0216] 2mm≤TH56≤2.5mm;

[0217] 2mm≤TH67≤2.5mm.

[0218] When the above conditions are met, the total optical length (TTL) of the dual telecentric lens can be guaranteed to be: TTL≤500mm, thus achieving a compact structure.

[0219] In some embodiments, the centering coefficient of lens 11 is greater than 0.05, and / or lens 11 is a spherical lens, and / or the aspect ratio and the diameter-to-edge ratio of lens 11 are both less than 10.

[0220] By having a centering coefficient greater than 0.05, the sensitivity of lens 11 to assembly tilt can be reduced, thereby reducing the assembly difficulty.

[0221] For example, the first lens 111 is a plano-convex lens, the second lens 112, the fourth lens 114, the fifth lens 115, and the sixth lens 116 are meniscus lenses, the third lens 113 is a plano-concave lens, and the seventh lens 117 is a biconvex lens. Each lens 11 is a spherical mirror. By rationally setting the surface shape of each lens and appropriately allocating the optical power, smooth edge light paths can be ensured, improving illumination uniformity.

[0222] With the aspect ratio and edge ratio of lens 11 both less than 10, the structure of lens 11 is stable and it is not easy to deform during assembly and use.

[0223] In some embodiments, the second type of telecardiogram group further includes an aperture stop 24a, which is located at the common focal point of the anterior and posterior telescope groups.

[0224] During operation, the light beam originating from the collimating lens group 22, which has already achieved a certain degree of collimation, first enters the front lens group, which consists of the first lens 111, the second lens 112, and the third lens 113. As a complete optical subsystem, the front lens group's image-side focal point coincides with the plane of the aperture stop 24a. Therefore, any light beam emitted from any point in the object-side field of view, after being converged by the front lens group, will pass through the image-side focal point of the front lens group and then through the aperture stop 24a.

[0225] These beams then enter the rear mirror group, which consists of the fourth lens 114, the fifth lens 115, the sixth lens 116, and the seventh lens 117. Since the aperture stop 24a is also located at the object-side focal point of the rear mirror group, according to the principle of optical path reversibility, the light rays passing through the aperture stop 24a, after being refracted by the rear mirror group, will have their outgoing principal rays parallel to the optical axis of the illumination optical system.

[0226] The design of aperture stop 24a ensures that the beams of the sub-light sources are projected at the same angle, thereby achieving high uniformity and precision of the illumination field.

[0227] In addition, the magnification of the bi-telecardiogram group 10 can also be equal to 1. When the magnification of the bi-telecardiogram group 10 can also be equal to 1, the bi-telecardiogram group 10 does not have the function of magnifying or reducing light, nor does it compress the divergence angle of the beam. It only transmits the collimated light and projects it onto the image plane.

[0228] It should be noted that this application does not impose further restrictions on the parameters, quantity, and arrangement of the light source 21d, the type of microlens array (spherical, aspherical, freeform, etc.), or the magnification and configuration of the second type of telecentric lens group; it only needs to meet the requirements of the illumination optical system.

[0229] Example 2

[0230] The illumination optical system provided in this embodiment 2 includes a light source 21d, a collimating lens group 22d, and a double telecentric lens group 10d. Among them, the light source 21d is a VCSEL light source array, the collimating lens group 22d is an aspherical microlens array, and the double telecentric lens group 10d is a second type of double telecentric lens group.

[0231] In Example 2, the illumination optical system is described using the second type of telecardiogram group, which is a 7-piece 0.6x telecardiogram group.

[0232] The VCSEL light source array consists of sub-light sources arranged in an array with a wavelength of 850nm. The lenses in the microlens array adopt a plano-convex lens structure with a thickness of 0.3mm at the center of the optical axis. The front surface 221 is flat, the radius of curvature of the rear surface 222 is -0.633mm, the conicity is -0.617, and the selected material has a refractive index of 1.69 and an Abbe number of 53.1.

[0233] The structure of the 10-day bipolar endocardiogram group is as follows: Figure 18 As shown, the object plane is the rear surface 222 of the microlens array. The specific structural parameters are shown in Table 3. All 7 lenses 11 are spherical mirrors. The glass material is selected from high-frequency production materials of Chengdu Guangming, with grades H-ZF4A, H-LAK52, H-ZF88, and H-ZPK5.

[0234] Table 3. Specific parameters of the 0.6x dual telecardiography group in Example 2

[0235]

[0236] It should be noted that the lens spacing refers to the air gap between two adjacent lenses 11 in the second type of telecentric lens group. Taking the lens spacing of 12.00 corresponding to the first lens 111b in Table 3 as an example, it can be understood that the central air gap TH12 between the first lens 111b and the second lens 112b is 12.00. Similarly, the lens spacing of 9.59 corresponding to the second lens 112b can be understood as the central air gap TH23 between the second lens 112b and the third lens 113b is 9.59, and so on. The lens spacings in Table 3 will not be explained individually again.

[0237] The second type of telecentric scope has a magnification of 0.6x, a total length of 490mm, an image-side working distance of 230mm, an object-side full field of view of 25mm, an object-side NA of 0.02, an object-side and image-side telecentricity of less than 0.05°, and a maximum distortion of less than 0.1%.

[0238] A collimated light beam first enters the front mirror group, which consists of the first lens 111b, the second lens 112b, and the third lens 113b. As a complete optical subsystem, the image-side focal point of the front mirror group coincides with the plane of the aperture stop 24a. Therefore, a light beam emitted from any point in the object-side field of view, after being converged by the front mirror group, will pass through the image-side focal point of the front mirror group and then through the aperture stop 24a. These light beams then enter the rear mirror group, which consists of the fourth lens 114b, the fifth lens 115b, the sixth lens 116b, and the seventh lens 117b. After refraction by the rear mirror group, the beam exits.

[0239] Figures 17-22 These are 10d pixel quality evaluation images from a 0.6x dual telecardiogram group. Figure 19The modulation transfer function curves of the lens group show that the MTF is >0.3@45lp / mm, and the MTF curves across the entire field of view are close to the diffraction limit. Figure 20 The image quality of the lens group is good, as shown in the dot plot of the lens group. The RMS radius of the entire field of view is smaller than the Airy disk radius. Figure 21 The distortion curve for the lens group shows a distortion degree of less than 0.1%.

[0240] The manufacturability evaluation parameters of each lens in the 10d bi-telecardiography group are shown in Table 4. The centering coefficient is >0.05, the radius of curvature to diameter ratio is >0.8, and the diameter-to-thickness ratio and diameter-to-edge ratio are both <10. These parameters ensure that the second type of bi-telecardiography group has excellent manufacturability.

[0241] Table 4. Manufacturability evaluation parameters for the 0.6x bicentroscopic group in Example 2

[0242]

[0243] Figure 22 This is a simulation diagram of the light distribution of the VCSEL array light source in the illumination optical system provided in Example 2 at the rear surface of the microlens array and the image plane. The light from the output array is uniformly reduced and projected onto the image plane, resulting in a uniform light spot distribution on the image plane without crosstalk distortion.

[0244] Embodiment 2 of this application can effectively improve the object-side field of view and output beam quality of the system. While effectively compressing the divergence angle, it limits the 21d surface diameter of the light source. The system has the advantages of high image quality output and strong manufacturability. It can better adapt to the collimation dot matrix illumination requirements of large-size VCSEL light source arrays. The long image-side working distance effectively avoids spatial interference and image plane heat accumulation with other systems, improves the applicability of the system, and can simultaneously meet the needs of various laser application scenarios with multiple light source 21d parameter arrangement types and multiple illumination requirements. It improves the applicability of laser in long-distance sensing, laser precision measurement and uniform dot matrix illumination scenarios.

[0245] Example 3

[0246] The illumination optical system provided in this embodiment 3 includes a light source 21d and a double telecentric lens group 10d. The light source 21d is a large-aperture light source with a certain divergence angle, and the double telecentric lens group 10d is a third type of double telecentric lens group.

[0247] In Example 3, the illumination optical system is described using the third type of telecentric lens group, which is a 7-piece 1.5x telecentric lens group.

[0248] See Figure 23Specifically, the light beam emitted by the light source 21d first enters the front mirror group, which consists of the first lens 111c, the second lens 112c, and the third lens 113c. As a complete optical subsystem, the image-side focal point of the front mirror group coincides with the plane of the aperture stop 24a. Therefore, any light beam emitted from any point in the object-side field of view, after being converged by the front mirror group, will pass through the image-side focal point of the front mirror group and then through the aperture stop 24a. These light beams then enter the rear mirror group, which consists of the fourth lens 114c, the fifth lens 115c, the sixth lens 116c, and the seventh lens 117c. After refraction by the rear mirror group, they exit.

[0249] The illumination optics system can be used to adjust the aperture and reduce the divergence angle of the light source 21d. The parameters of the light source 21d and the double telecentric lens group 10d can be flexibly changed to adapt to the aperture and divergence angle requirements of the light source 21d in various application scenarios.

[0250] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0251] In the description of this application, it should be understood that the terms “comprising” and “having” as used herein, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are expressly listed, but may include other steps or units that are not expressly listed or that are inherent to such process, method, product, or apparatus.

[0252] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the connection within two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0253] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An illumination optical system, characterized in that, include: A light source (21) comprising a sub-light source configured to emit a beam of light; Collimating lens group (22), along the light emission direction of the sub-light source, the collimating lens group (22) is located on the light emission side of the light source (21), and the collimating lens group (22) is configured to collimate the light beam; The double telecentric lens group (10) is located on the light-emitting side of the collimating lens group (22) and is configured to project the light beam collimated by the collimating lens group (22) onto the image plane; the double telecentric lens group (10) includes a plurality of lenses (11) arranged sequentially along the optical axis direction, and the optical axis direction of the double telecentric lens group (10) is parallel to the light-emitting direction of the sub-light source.

2. The illumination optical system according to claim 1, characterized in that, The image-side working distance of the illumination optical system is greater than 200mm.

3. The illumination optical system according to claim 2, characterized in that, The total optical length of the illumination optical system is less than 500 mm.

4. The illumination optical system according to claim 1, characterized in that, The root mean square radius of the full field of view of the illumination optical system is smaller than the Airy disk radius corresponding to the double telecentric lens group (10).

5. The illumination optical system according to claim 4, characterized in that, The object-side telecentricity and image-side telecentricity of the illumination optical system are both less than 0.055°.

6. The illumination optical system according to claim 5, characterized in that, The maximum distortion of the illumination optical system is less than 0.3%.

7. The illumination optical system according to claim 1, characterized in that, The object-side full field of view of the illumination optical system is greater than 0 mm and less than or equal to 25 mm.

8. The illumination optical system according to any one of claims 1-7, characterized in that, The magnification of the bi-telecardiogram group (10) is greater than 1.

9. The illumination optical system according to claim 5, characterized in that, Along the optical axis of the double telecentric lens group (10), the plurality of lenses (11) include a first lens (111), a second lens (112), a third lens (113), a fourth lens (114), a fifth lens (115), a sixth lens (116), and a seventh lens (117) arranged sequentially from the collimating lens group (22) to the image side. The first lens (111), the second lens (112), the fifth lens (115), the sixth lens (116), and the seventh lens (117) all have positive optical power, and the third lens (113) and the fourth lens (114) all have negative optical power; the first lens (111), the second lens (112), and the third lens (113) form the front lens group, and the fourth lens (114), the fifth lens (115), the sixth lens (116), and the seventh lens (117) form the rear lens group, which is a telephoto structure.

10. The illumination optical system according to claim 9, characterized in that, The dual telecardiogram group (10) also includes an aperture stop (24a), which is located at the common focal point of the anterior and posterior telescope groups.

11. The illumination optical system according to claim 9, characterized in that, The central air gap between the first lens (111) and the second lens (112) is TH12, the central air gap between the second lens (112) and the third lens (113) is TH23, the central air gap between the third lens (113) and the fourth lens (114) is TH34, the central air gap between the fourth lens (114) and the fifth lens (115) is TH45, the central air gap between the fifth lens (115) and the sixth lens (116) is TH56, and the central air gap between the sixth lens (116) and the seventh lens (117) is TH67, wherein: ； ； ； ； ； 。 12. The illumination optical system according to claim 9, characterized in that, The centering coefficient of the lens (11) is greater than 0.05, and / or the lens (11) is a spherical lens, and / or the aspect ratio and the diameter-to-edge ratio of the lens (11) are both less than 10.

13. The illumination optical system according to claim 9, characterized in that, The magnification of the bicentroscopic set (10) is 1.

5.

14. The illumination optical system according to any one of claims 1-7, characterized in that, The magnification of the bicentroscopic group (10) is less than 1.

15. The illumination optical system according to claim 14, characterized in that, Along the optical axis of the double telecentric lens group (10), the plurality of lenses (11) include a first lens (111), a second lens (112), a third lens (113), a fourth lens (114), a fifth lens (115), a sixth lens (116), and a seventh lens (117) arranged sequentially from the collimating lens group (22) to the image side (11). The first lens (111), the second lens (112), the fifth lens (115), the sixth lens (116), and the seventh lens (117) all have positive optical power, and the third lens (113) and the fourth lens (114) all have negative optical power; the first lens (111), the second lens (112), and the third lens (113) form the front lens group, and the fourth lens (114), the fifth lens (115), the sixth lens (116), and the seventh lens (117) form the rear lens group, which is a telephoto structure.

Images