352 results about "Aspheric lens" patented technology

The invention relates to the technical field of optical detection, in particular to an aspheric lens laser interference detection adjustment error separation system and method, and the method comprises the steps: placing an aspheric lens on a clamping platform, carrying out the multiple laser interference measurement through adjusting different pitch angles and azimuth angles, and collecting a multi-angle interference fringe image; for different installation and adjustment error types, key features of typical error fringe images are extracted and compared with current interference fringe images, and identification of the installation and adjustment error types and levels is achieved; a mathematical model of various installation and adjustment errors is constructed, polynomial parameterization representation is adopted, installation and adjustment compensation parameters are reversely solved according to an identification result, and installation and adjustment are completed; and repeating the measurement and analysis process, and constructing an error adjustment frequency optimization model until the precision requirement is met. The method provided by the invention can improve the adjustment efficiency and precision of the aspherical lens.

The application discloses a multi-marked endoscopic imaging lens for digestive tract, and belongs to the field of biomedical microscopic endoscopic imaging. The endoscopic imaging lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens; the first lens focuses laser; the second lens is matched with the first lens to limit a light beam in an effective light aperture of the lens; the third lens corrects chromatic aberration; the fourth lens and the fifth lens are combined to correct aberration; the sixth lens adopts an aspheric lens to correct spherical aberration caused in a collimating and focusing system; and the seventh lens is matched with the sixth lens to correct chromatic aberration. The working spectral range of the microscopic objective lens group is 488-860 nm, the effective light aperture is less than 1.8 mm, the mechanical outer diameter is not greater than 2.6 mm, the numerical aperture at the object side or the tissue is 0.55, the imaging field of view is 450 microns, the magnification is 2.14 times, and the working distance is 84 microns. The effect of matching excitation and fluorescence spectrum of a clinically available fluorescence contrast agent is realized.

The utility model provides a glass-plastic hybrid optical system and a camera module using the same, the glass-plastic hybrid optical system is composed of eight lenses, one spherical glass lens, one aspheric glass lens and six plastic aspheric lenses are selected, and the refractive power and the surface type of each lens are reasonably configured. Therefore, the optical lens can have the advantages of being small in size, low in cost and large in aperture while having a large field angle range, can better capture detail information of an object, improves the detail capturing capability of the optical lens for shooting the object, improves the picture texture of the optical lens, improves the resolution ratio and imaging definition of the optical lens, and improves the imaging quality of the optical lens. Therefore, the requirements of people on wide angle and high-quality imaging of the motion camera can be met.

The utility model discloses a visible light optical system and a visible light optical lens. The visible light optical system comprises a first aspheric lens, a second aspheric lens, a super lens, a third aspheric lens, a fourth aspheric lens, a fifth aspheric lens and a sixth aspheric lens. The focal powers of the first aspheric lens, the super lens and the fifth aspheric lens are positive; the object side surface and the image side surface of the first aspheric lens are convex towards the object side; the object side surface and the image side surface of the second aspheric lens are convex towards the object side; the super lens comprises a substrate and a micro-nano structure, wherein the micro-nano structure is arranged on the object side surface and / or the image side surface of the substrate; the focal power of the fourth aspheric lens and the sixth aspheric lens is negative; the image side surface of the fifth aspheric lens protrudes towards the image side; wherein the sixth aspheric lens has the maximum focal power among the lenses with negative focal power. The visible light optical system provided by the utility model is relatively excellent in imaging quality, and the visible light optical system is relatively small in size.

The embodiment of the utility model discloses an ultra-wide-angle and ultra-short-focus full-width camera lens, which comprises sixteen lenses which are sequentially arranged from an object space to an image space along an optical axis, and each lens has corresponding focal power; besides, a diaphragm is arranged between the eighth lens and the ninth lens to divide the sixteen lenses into two lens groups, namely a first lens group with negative total focal power and a second lens group with positive total focal power. According to the full-frame prime lens provided by the embodiment of the utility model, by using the optical structure of the 14 glass spherical lenses and the 2 glass aspherical lenses, when the full field angle is greater than or equal to 132 degrees, the distortion is small, and the purple edge phenomenon is improved. Besides, by adding the aspherical lens, the image quality of an edge field of view is also obviously improved under an ultra-short focal length, clear imaging can be realized, and the shooting feeling of almost zero distortion is achieved.

The invention relates to a surface type correction and processing method of an aspherical lens, which comprises the following steps of: changing a radial point location of a polishing disk participating in cutting by adopting a rotary polishing disk and lens tangent layout and through three-axis linkage of numerical control X-axis radial feeding, numerical control B-axis swinging and Z-axis approaching movement, and forming differentiation by utilizing the linear velocity gradient of the disk to remove redundant materials of the lens; and surface shape error differential correction is realized. According to the method, the polishing head does not need to be frequently replaced, over-polishing / under-polishing of traditional air bag polishing is eliminated, and the single-piece machining time is shortened; an air bag structure is omitted, the service life of consumables is prolonged, and batch fluctuation is reduced; accumulative errors are reduced through three-axis linkage, and medium-high frequency ring belt errors are restrained. The matched processing method comprises the steps of initial forming, detection, planning, correction and the like, can be quickly adapted to lenses of multiple specifications, and efficiently completes high-precision batch manufacturing of medium and large-caliber aspheric surfaces.

The invention discloses a diffractive hybrid high-image-quality lens, and the lens sequentially comprises a first lens with negative focal power from an object side to an image side along an optical axis, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with negative focal power and a fifth lens with negative focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a convex surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a concave surface; the lens at least comprises an aspheric lens. A diaphragm is arranged between the first lens and the second lens. The five aspherical lenses in specific shapes are adopted, through reasonable matching of the surface types and the focal power of all the lenses and reasonable arrangement of the position of the diaphragm, the system can have high image quality and low chromatic aberration, the full field angle reaches 110 degrees or above, and the distortion of the system is lower than 2%.

The invention belongs to the technical field of laser, and particularly discloses a beam shaping system and method based on prism pair orthogonality and cascade, and the system comprises a single-mode fiber, an aspherical lens, a first prism pair, a first parallel plate, a second prism pair and a second parallel plate which are sequentially arranged along the direction of an optical axis. A Gaussian beam emitted by a single-mode optical fiber is collimated by an aspherical lens to form a parallel beam, the beam is expanded or compressed in the X direction by a first prism pair, the beam is expanded in the Y direction by a second prism pair, and two inclined parallel plates are respectively used for compensating the beam offset in the X / Y direction; according to the invention, the circular Gaussian beam emitted by the single-mode fiber can be shaped, a large strip-shaped collimation light spot with an adjustable length-width ratio from 4: 1 to 20: 1 and a long axis size of 30mm can be realized, and the central positions of the input and output beams in the cross section are ensured to be unchanged.

The invention discloses a visible light optical system and a visible light optical lens. The visible light optical system comprises a super lens, a first aspheric lens, a second aspheric lens, a third aspheric lens and a fourth aspheric lens. The first aspheric lens, the second aspheric lens, the third aspheric lens and the fourth aspheric lens are sequentially arranged from the object side to the image side along the optical axis. The focal power of the super lens is positive; the focal power of the first aspheric lens is positive, and the object side surface and the image side surface of the first aspheric lens both protrude towards the object side; the focal power of the second aspheric lens is negative, and the object side surface and the image side surface of the second aspheric lens both protrude towards the image side; the focal power of the third aspheric lens is positive, the object side face and the image side face of the third aspheric lens both protrude towards the image side, and the focal power of the fourth aspheric lens is negative. According to the visible light optical system, the super lens is combined with the traditional refraction lens, so that the visible light optical system has the advantages of low cost, small size and excellent imaging quality.

The invention relates to the technical field of aspherical lens machining, in particular to an edge milling device for aspherical lens machining, which comprises a clamping assembly, a first milling assembly and a second milling assembly, the milling assembly comprises a milling cutter for grinding the edge of the aspherical lens and a grinding rod for grinding the surface of the aspherical lens; the fixing assembly is used for fixing the milling cutter and the polishing rod; the protection assembly is arranged outside the clamping plates in a sleeving manner and is used for surrounding the lens between the two groups of clamping plates; the grinding device has the beneficial effects that through cooperation of the bolts and the mounting plates, the grinding rods are mounted on one sides of the clamping plates, then the lens is adsorbed to the other set of clamping plates, surface grinding of the aspheric lens is achieved, when the edge of the aspheric surface needs to be ground, the lens is clamped through the clamping assemblies, a milling cutter is driven by the connecting rods to be inserted between the two sets of clamping plates, and grinding is achieved. The edge of the aspherical lens is ground, all-directional grinding machining of the aspherical lens can be achieved without replacing equipment, and the production efficiency is improved.

The wide-angle lens comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from an object plane to an image plane along an optical axis, the first lens is a glass spherical lens with negative focal power, the object side face of the first lens is a convex face, and the image side face of the first lens is a concave face. The second lens is a plastic aspheric lens with negative focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface. The third lens is a plastic aspheric lens with positive focal power, the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface. The fourth lens is a plastic aspheric lens with positive focal power, the object side surface of the fourth lens is a convex surface or a concave surface, and the image side surface of the fourth lens is a convex surface. The glass spherical surface and the plastic aspheric surface are matched and combined, the resolution is improved, the total axis length is smaller than 10.5 mm, the aperture F can reach 1.6, the field angle FOV can reach 183 degrees, the relative illumination can reach 50%, and the lens has the advantages of being large in aperture, ultra-large in field angle, small in size and high in illumination.

The invention belongs to the technical field of optical thin film design and preparation, and particularly relates to a preparation method of a multilayer composite antireflection film on the surface of an optical lens. The preparation method comprises the step of sequentially performing atomic layer deposition on the surface of the optical lens to form the transition layer, the high-refractive-index layer, the low-refractive-index layer, the high-refractive-index layer and the packaging layer. According to the atomic layer deposition method, uniform coating can be achieved on the surfaces of aspherical lenses with different curvature radiuses, and five layers of oxide films are deposited through alternating pulse in an ALD pulse sequence with the structure of'substrate layer-transition layer-high refractive index layer-low refractive index layer-high refractive index layer-packaging layer '. And an excellent antireflection effect in a visible light wavelength range is realized. The atomic layer deposition is carried out at low temperature (25-150 DEG C), so that the atomic layer deposition can be directly coated on the high-molecular polymer lens, and the deformation of the base material due to high temperature is avoided; the method is especially suitable for different application scenes such as consumer electronics, personal protection and medical assistance.

The invention relates to a refractive and super hybrid visible light pick-up lens and electronic equipment, and belongs to the field of optical lenses, the refractive and super hybrid visible light pick-up lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are sequentially arranged from an object plane to an image plane along an optical axis, and the other lenses are aspheric lenses. According to the invention, the large aperture and low distortion are realized through the eight-piece design, the total optical length is effectively compressed, the system is more miniaturized, lighter and thinner, and the surface type complexity of the aspherical lenses is reduced.

The invention discloses a multi-label endoscopic imaging lens for a digestive tract, and belongs to the field of biomedical microscopic endoscopic images. The endoscopic imaging lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The first lens focuses laser, and the second lens is matched with the first lens to limit a light beam in an effective clear aperture of the lens; the third lens corrects chromatic aberration; a fourth lens and a fifth lens are combined to correct aberration; the sixth lens is an aspheric lens and corrects spherical aberration brought in collimation and focusing systems, and the seventh lens is matched with the sixth lens to correct chromatic aberration. The working spectral range of the microscope objective set is 488-860 nm, the effective clear aperture is smaller than 1.8 mm, the mechanical outer diameter is not larger than 2.6 mm, the numerical aperture at the object space or the tissue is 0.55, the imaging view field is 450 microns, the magnification factor is 2.14 times, and the working distance is 84 microns. And the effect of matching excitation and fluorescence spectrum of a clinically available fluorescence contrast agent is realized.

The utility model discloses a prime lens comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are arranged from an object plane to an image plane along an optical axis. The first lens is a negative focal power lens, the second lens is a negative focal power lens, the third lens is a positive focal power lens, the fourth lens is a positive focal power lens, the fifth lens is a negative focal power lens, the sixth lens is a positive focal power lens, and the seventh lens is a negative focal power lens. The eighth lens is a positive focal power lens; and the third lens or the fourth lens is a glass aspheric lens. According to the technical scheme, the number of the lenses, the focal power matching mode and the surface type matching mode are reasonably set, and the design of the fixed-focus lens which is large in aperture, small in size and capable of being confocal day and night can be achieved.

The invention relates to an ultra wide angle pick-up lens suitable for a vehicle-mounted OMS system, an optical system of the lens is composed of a first lens, a second lens, a diaphragm, a third lens, a fourth lens and a fifth lens which are sequentially arranged from left to right along a light incident light path, the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, and the diaphragm is a meniscus concave negative lens. The third lens is a biconvex positive lens, the fourth lens is a biconvex positive lens, the fifth lens is a meniscus concave negative lens, the fourth lens and the fifth lens form an achromatic doublet lens, the first lens and the third lens are both made of glass materials and are spherical lenses, and the second lens, the fourth lens and the fifth lens are all plastic aspheric lenses. By adopting the glass-plastic mixed optical structure of the two glass spherical lenses and the three plastic aspheric lenses, the advantage of aberration correction of the aspheric lenses is brought into full play, high-definition imaging is met, the lens outer diameter is smaller, the optical total length is shorter, and miniaturization of the lens is ensured.

The embodiment of the invention provides a projection lens module and projection equipment. Wherein the projection lens module sequentially comprises a first lens group, a diaphragm and a second lens group along the optical axis direction; the first lens group comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged along an optical axis, and the first lens and the third lens are both aspheric lenses; the second lens group comprises a doublet lens and an eighth lens which are arranged along the optical axis, and the eighth lens is an aspheric lens; the diaphragm is positioned between the fifth lens and the doublet lens; the projection lens module comprises a first lens and a second lens, the first lens is a biconcave lens, the first lens is a lens with the largest aperture in the projection lens module, the first lens meets the condition that TTL / D1 is larger than 4.3 and smaller than 5.1, TTL is the total optical length of the projection lens module, and D1 is the aperture of the first lens.

The invention provides a photoetching aberration compensation driving parameter disturbance precursor prediction method and system, and the method comprises the steps: firstly, synchronously capturing a frequency band compensation residual error sequence of 3 * 3 grid measurement points of an aspherical lens, intercepting 30ms window data, generating a time-frequency spectrum matrix through Hamming window STFT, and then extracting three feature vectors; inputting the feature vector into a two-layer LSTM predictor to output a disturbance probability P and pre-judgment time delta t and Pgt; 0.7, triggering the resetting of the driving parameters; dynamically adjusting the iteration step length and the driving voltage based on the P and the delta t, and outputting the iteration step length and the driving voltage to a compensator to generate compensation wavefront correction aberration; if the wavefront error RMS value is gt; and 0.05 lambda, only updating the weight of the LSTM output layer and performing re-prediction to form a closed-loop compensation process.

An imaging optical system wherein the number of lenses is three or four, an aperture stop is located between the lens closest to the object and the lens closest to the image, a single aspheric lens in which radius of curvature of each surface is infinity in the paraxial region and which has a power of the third-order aberration region in the peripheral area is provided at a position not adjacent to the aperture stop, the lens closest to the object is a negative lens or the aspheric lens, at least one positive lens is located closer to the image than the aperture stop,0.18<(∑i=1i=n<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[LeftBracketingBar]"< / annotation>< / semantics>1fi<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[RightBracketingBar]"< / annotation>< / semantics>)·fn<0.9is satisfied, a bundle of rays reaching the maximum image height and a bundle of rays having the principal ray parallel to the optical axis do not intersect with each other within the first lens from the object side, and40⁢°<HFOV<80⁢°is satisfied.

The invention discloses an optical imaging lens group, a scanning display device and application, and relates to the technical field of scanning display. The optical imaging lens group provided by the invention comprises six lenses which are sequentially arranged along a common optical axis from a first side to a second side, the second lens is a meniscus aspheric lens, the object side surfaces of the first lens and the second lens are convex surfaces, and the image side surfaces of the first lens and the second lens are concave surfaces; the fourth lens is a biconcave lens, the fourth lens and one of the third lens and the fifth lens adjacent to the fourth lens form a glued lens, and the focal power of the other lens is positive; the image side surface of the sixth lens is a convex surface, and the object side surface of the sixth lens is a concave surface; and the focal length value of the image side surface of the second lens and the ratio of the curved surface radius of the sixth lens to the working distance of the sixth lens are limited, and the optical imaging lens group adopts spherical and aspherical lenses, so that the number of the lenses is reduced, and the imaging quality is improved, and the application of the lens group in a long working distance is met.

The utility model relates to a tool for machining an aspheric lens array, and relates to the technical field of optical part machining, the tool is used for fixing a lens body when the surface of an aspheric lens is machined, the tool comprises an installation substrate and a lens installed in the middle of the installation substrate, an installation hole is formed in the middle of the installation substrate in a penetrating mode, and the lens is embedded in the installation hole; arc grooves are symmetrically formed in the two opposite sides of the mounting base plate, and the axes of the two arc grooves coincide with the axis of the mounting hole. According to the tool jig designed by the invention, the machining of the double-sided aspheric lens can be met, and meanwhile, the wall thickness, the position precision and the relatively high coaxiality requirements of the channel can be well ensured.

The invention discloses a photoelectric co-packaging adapter plate and a photoelectric co-packaging device. A photoelectric co-packaging adapter plate comprises a first coating layer and a second coating layer which are formed on a substrate, and an optical waveguide arranged between the first coating layer and the second coating layer, and the refractive index of the optical waveguide is larger than the refractive index of the first coating layer and the refractive index of the second coating layer; a light emitting window is formed in the second coating layer, an aspherical lens is arranged on the light emitting window, a first reflecting part is arranged at the first end part of the optical waveguide, and the first reflecting part is used for forming a light path between the optical waveguide and the aspherical lens. According to the technical scheme provided by the invention, loss caused by mismatching of a micro-nano optical chip mode field and a silicon optical waveguide mode field is reduced, and alignment precision requirements between different modules are reduced.

The invention discloses a large-image-plane video small lens and a camera, and relates to the technical field of optical lenses, and the large-image-plane video small lens is provided with an object side and an image side which are oppositely arranged along the optical axis direction. The small video camera with the large image plane comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are sequentially arranged from the object side to the image side. Wherein the first lens, the second lens, the fourth lens, the fifth lens, the seventh lens and the eighth lens are plastic aspherical lenses, and the third lens and the sixth lens are glass aspherical lenses; the resolution ratio of the large-image-plane video small lens is greater than or equal to 12M, the image plane height of the large-image-plane video small lens is phi, and the total optical length of the large-image-plane video small lens is TTL, 1lt; tTL / phi < = 1.5. The technical effects of large imaging surface, good imaging effect and small size are achieved through arrangement and combination of the eight lenses, material selection, surface type distribution and parameter design of the lenses.

An optical system disclosed in an embodiment of the present invention includes first to third lenses arranged from an object toward an image sensor along an optical axis, and an optical filter disposed between the second lens and the third lens, in which the first lens has a negative refractive power, and the third lens has a negative refractive power. At least one spherical lens adjacent to the object and at least one aspheric lens adjacent to the image sensor are included among the first to third lenses, and the number of spherical lenses among the first to third lenses is greater than the number of aspheric lenses. A center distance between the first lens and the second lens is greater than a center thickness of the first lens, the second lens includes a shape that is convex on both sides on an optical axis, and refractive indexes of the first to third lenses may be less than 1.9.

The present invention discloses a single-group mobile long-wave dual-field optical system that integrates magnification and focusing. From the object side to the image side, the system comprises a first lens, a second lens, a third lens, and a fourth lens connected in sequence. The first lens is a meniscus diffraction lens with positive focal length and a convex surface curved toward the object side. The second lens is a meniscus aspheric lens with negative focal length and a convex surface curved toward the object side. The third lens is a meniscus aspheric lens with negative focal length and a convex surface curved toward the object side. The fourth lens is a meniscus diffraction lens with positive focal length and a convex surface curved toward the image side. The first lens is a fixed group, and the second, third, and fourth lenses together form a mobile group. The present invention achieves field switching and focusing functions through the movement of a single group. The system has a simple structure, greatly simplifies the mechanical structure, reduces the difficulty of assembly and adjustment, and improves the stability and reliability of the system. The system consists of four lenses, with a small number of lenses, low cost, and high optical transmittance.

The invention discloses an optical-ultrahigh frequency combined sensing GIS partial discharge monitoring system and method. The system comprises an ultrahigh frequency detection unit, an optical detection unit and a signal composite output unit, wherein the ultrahigh frequency detection unit and the optical detection unit are arranged in parallel; the ultrahigh-frequency detection unit is used for detecting ultrahigh-frequency electromagnetic signals in the GIS cavity; the optical detection unit comprises a large-view-field optical lens, an optical conduction assembly and a photoelectric converter which are connected in sequence; the large-view-field optical lens is formed by combining a plurality of aspherical lenses, and the large-view-field optical lens is used for converging optical signals in the GIS cavity; the optical conduction assembly comprises an optical fiber bundle which is used for receiving and conducting optical signals; the photoelectric converter comprises a silicon photomultiplier tube or a photomultiplier tube, and is used for converting a weak optical signal into an electric signal; the signal composite output unit is respectively connected with the ultrahigh frequency detection unit and the optical detection unit, and the signal composite output unit is used for outputting signals of the ultrahigh frequency detection unit and the optical detection unit.

An optical system of the lens is composed of a first lens, a second lens and a third lens which are sequentially arranged from left to right along a light incident light path, the first lens is a plano-convex lens with positive focal power, the object side face of the first lens is a convex face, and the image side face of the first lens is a plane; the second lens is a meniscus lens with positive focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the third lens is a meniscus lens with negative focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the first lens is a glass spherical lens, and the second lens and the third lens are plastic aspheric lenses. A glass-plastic mixed optical system is formed by one glass spherical lens and two plastic aspheric lenses, and the lenses have high resolution, low distortion and low temperature drift by reasonably distributing the focal power and the surface type of each lens, the central thickness of each lens, the axial distance between the lenses and the like, and can clearly image at the temperature of-40 DEG C to 105 DEG C; the total length of the lens is greatly shortened, and miniaturization requirements are met.

The application provides a compact internal focusing wide-angle photographic lens, which comprises, in sequence from the object side to the image side along the optical axis, a first lens group with negative refractive power, an aperture stop, a second lens group with positive refractive power, and a third lens group with negative refractive power; during the focusing process from infinity to a close distance, the second lens group moves along the optical axis towards the object side; the first lens group contains at least two pieces of meniscus negative lenses, one of which is an aspheric lens, and satisfies the following condition formula: -7<F1 / F<-3, (1); the second lens group satisfies the following condition formula: 0.5<F2 / F<0.9, (2); wherein F represents the focal length of the photographic lens, F1 represents the combined focal length of the first lens group, and F2 represents the combined focal length of the second lens group. The application focuses by adopting the mode of internal single lens group movement, and good imaging quality and compact lens size are realized through reasonable optical design.

The utility model discloses a compact medium-wave infrared Cassegrain imaging system with a large view field. The imaging system comprises four parts, namely a perforated aspherical lens I (1), a main reflecting mirror (2), a secondary reflecting mirror (3) and an aspherical lens II (4). The focal length of the imaging system is 110mm, the clear aperture is 65mm, and the length from the front surface of the first perforated aspheric lens to the image plane is only 49mm which is less than half of the focal length of the system. According to the imaging system provided by the utility model, the reflector is arranged in the hole of the perforated aspheric lens I, so that the length of the system can be shortened, and more variables can be provided for aberration correction. The diameter of a defocused spot of the imaging system is smaller than 13 microns in a working wave band range of 3-5 microns, and the imaging system is suitable for a high-resolution medium-wave infrared detector; the imaging system has a large field of view of 1.3 degrees, the number of lenses is small, the transmittance is high, and imaging is clear in a wide temperature range through a mode that the second aspheric lens moves back and forth for focusing compensation.

An optical lens includes a first lens, a second lens, a third lens, a fourth lens and a cemented lens. The first lens is closest to a magnified side as compared with any other lens of the optical lens, one of the second lens and the third lens is a first aspheric lens, and the fourth lens is a second aspheric lens and disposed between the cemented lens and a minified side of the optical lens. The optical lens satisfies the condition: 1.0<D1 / DL<4.0, where D1 denotes a lens diameter of the first lens and DL denotes a lens diameter of the fourth lens.