73results about How to "Avoid out of focus" patented technology

The invention discloses a curved-surface bionic compound eye imaging device for a zoom lens array, and belongs to the field of lens bionic compound eye imaging devices according to a curved-surface array. The curved surface of a glass spherical shell of the device is provided with a lens array which consists of single eyes at a plurality of layers, wherein the curvatures and focal lengths of the single-eye lenses at all layers change layer by layer, but all the single-eye lenses are focused on the surface of a unique plane image sensor, thereby enabling the single-eye lens located at the edge of a view field to be able to be effectively focused, and avoiding a defocused state. According to the invention, a sieve-mesh-shaped metal hole array covers the surface of an image sensor, and each sieve mesh is enabled to be corresponding to one independent monocular lens optical path, thereby achieving an effect of segmenting the view field, achieving the integrated jointing of all monocular lens images, and preventing the interference and impact among the adjacent monocular lenses. The device is also high in resolution, is high in instantaneity, is easy to miniaturize, is easy to become light, and is convenient for manufacturing and maintenance.

The invention belongs to the technical field of laser cutting and particularly relates to a laser continuous cutting device having a dedusting function. The laser continuous cutting device comprises a dedusting mechanism and a laser cutting mechanism. The laser cutting mechanism comprises a laser head and a cushion seat module. The cushion seat module comprises a center shaft, a rotating roller and a fixed roller. The rotating roller and the fixed roller have the same radius, the fixed roller is connected with the rotating roller through the center shaft and is fixed relative to the center shaft, and the rotating roller can rotate relative to the center shaft. When a pole piece is cut, the pole piece adheres to the rotating roller by means of tension provided by mechanical transmission during the feeding, and a to-be-cut pole lug reserved area on the pole piece adheres to the fixed roller. The linear velocity of the rotating roller and the feeding speed of the pole piece are the same, so that no sliding friction occurs between the pole piece and the rotating roller, and the damage to the pole piece caused by the sliding friction between the pole piece and the rotating roller is avoided.

The invention provides a focusing method and a focusing device and belongs to the video monitoring technology field. The method comprises steps that a preparatory focus area is acquired according to focusing point clear values of images of multiple detection positions acquired by an image acquisition device; if a change state of the focusing point clear values of the preparatory focus area is abnormal, a next preparatory focus area and a focusing point clear value change state of the next preparatory focus area are acquired till the focusing point clear value change state of the next preparatory focus area is normal; a standard focus position is acquired for the normal preparatory focus area according to the focusing point clear value change state; the image acquisition device is controlled for moving to a detection position corresponding to the standard focus position. According to the method, through determining whether the focusing point clear value change state of the preparatory focus area is normal, falling into a local extremum can be avoided, search steps of the standard focus point position are reduced, a focusing process is greatly simplified, and focusing accuracy is improved.

The invention relates to an image capturing device, including a lens, an image sensor for converting an optical signal of a subject into an electrical signal, a focusing unit for the focusing of the image capturing device and a shooting control device for inputting shooting signals to the image capturing device. The focusing unit includes an image processing unit, a lens driving unit and a comparison unit. The image processing unit is connected with the image sensor, allowing that when the lens is located at different locations, the analysis and calculation on the electronic signals outputted by the image sensor can be applied to obtain the location of the lens in case of the accurate focusing of the image capturing device. The lens driving unit can move the lens to the location of accurate focusing. The comparison unit is used for judging the movement of the subject leads to the lowering of the image quality beyond the regulated scope before the image capturing device shoots the subject and is used for determining whether the re-focusing on the image capturing device is required. In addition, the invention also provides an automatic focusing method of the image capturing device.

The invention provides a focusing system of a digital camera. The system comprises a receiving module, a focusing module, a judging module and a selection module, wherein the receiving module is used for receiving a focusing mode selected by a user; the focusing module is used for focusing when the user semi-presses a shutter according to the focusing mode selected by the user; the judging module is used for judging whether the focusing is successful; the selection module is used for automatically reselecting the most proper focusing mode when the focusing is failed; and the focusing module is also used for completing the focusing according to the selected most proper focusing mode when the focusing is failed. The invention also provides a method for focusing the digital camera. The focusing system can automatically and accurately select the most proper focusing mode for focusing under the condition that the user improperly selects the focusing mode.

The invention provides a method for preventing uneven surface of a wafer, comprising the following steps: providing a substrate, wherein the substrate comprises a first surface and a second surface, the first surface is corresponding to the second surface and the first surface is formed with a semiconductor device layer; and then forming a protective layer on the second surface of the substrate. A method for preventing defocus in exposure, comprising the following steps: providing a substrate, wherein the substrate comprises a first surface and a second surface, the first surface is corresponding to the second surface and the first surface is formed with a semiconductor device layer; forming a protective layer on the second surface of the substrate; forming a photoresist layer; and then exposing the photoresist layer. The method for preventing uneven surface of a wafer and preventing defocus in exposure provided by the invention has the advantages that the phenomenon of uneven thickness of the wafer during the cleaning process is prevented and the defocus problem in photoresist exposure is prevented.

The invention discloses a silicon wafer bearing table for a photoetching machine, which comprises a bearing table base, a plurality of vacuum holes, a plurality of stress inductors, a connector and a silicon wafer transfer device, wherein the plurality of vacuum holes and the silicon wafer transfer device are arranged on the bearing table base; the connector is arranged at the bottom of the bearing table base; and the stress inductors are arranged on the surface of the bearing table base. The stress inductors are connected with an electric power conversion circuit of which the output end is connected with a terminal controller, and the terminal controller is connected with a power motor. The stress inductors realize expansion and regulate height by inducting the information of action points, magnitudes, directions and the like of acting force from silicon wafers. By regulating the height of each stress inductor which is in contact with the silicon wafers, the silicon wafer bearing table for the photoetching machine of the invention can ensure that the front sides of the silicon wafers are on the same horizontal plane at all times, thereby preventing the images on the front sides from being out of focus caused by contaminants of particles and the like on the back sides of the silicon wafers, and reducing rework of photoetching. The invention also discloses a use method of the silicon wafer bearing table for the photoetching machine.

The invention discloses a photographic device and a focusing compensation method. The photographic device comprises a sensor module, a motor control module, and a motor, wherein the sensor module is used for acquiring change value of acceleration of gravity of the photographic device, the motor control module is connected with the sensor module, and is used for acquiring the change value of acceleration of gravity from the sensor module, and judging whether the change value of the acceleration of gravity is greater than a default threshold value, if yes, the motor control module generates a control signal, the motor is connected with the motor control module, and the motor performs compensatory movement according to the control signal. Through adoption of the method, the photographic device is prevented from losing focus when holding gesture of a user changes, so that the experience effect of the user is improved.

The invention discloses a ballastless track slab temperature high speed dynamic measuring system. The ballastless track slab temperature high speed dynamic measuring system is used for measuring the temperature of a ballastless track slab; the ballastless track slab temperature high speed dynamic measuring system is mounted at the bottom of a train; and the ballastless track slab temperature highspeed dynamic measuring system comprises an optical information collection module, a photoelectric temperature measuring module and a temperature control box, wherein the optical information collection module is used for collecting spectral information of a sampling point of the ballastless track slab and transmitting the spectral information to the photoelectric temperature measuring module, thephotoelectric temperature measuring module is used for converting the spectral information into an electric signal and calculating the temperature of the sampling point according to the electric signal, and the temperature control box is used for adjusting the temperature of a working environment of the photoelectric temperature measuring module. According to the ballastless track slab temperaturehigh speed dynamic measuring system, with the train as a carrier, the temperature of the ballastless track slab of a railway line can be measured at a high speed in real time, and spatial sampling iscarried out at an equal interval of 250 mm to measure the temperature of the ballastless track slab under a double-direction (a forward direction and a reverse direction) running condition with trainspeed of 400 km / h in a high temperature or cold environment (a temperature range from a low temperature of -40 degrees to high temperature of 60 degrees).

The invention provides a carrier surface cleaning device and method. The carrier surface cleaning device comprises a wafer carrier, a chemical mechanical grinding head and a grinding head moving part,wherein a connecting end of the grinding head moving part comprises a rotating disc, the chemical mechanical grinding head rotates at a high speed under the driving of the rotating disc, a chemical cleaning agent spraying pipeline and a chemical cleaning agent recycling pipeline are arranged on the chemical mechanical grinding head, a guide outlet of the chemical cleaning agent spraying pipelineis located in the center of a grinding surface of the chemical mechanical grinding head, a suction inlet of the chemical cleaning agent recycling pipeline is located on the periphery of the grinding surface of the chemical mechanical grinding head, and the chemical cleaning agent spraying pipeline and the chemical cleaning agent recycling pipeline penetrate through the chemical mechanical grindinghead. According to the device, the influence of pollutants on wafer flatness is avoided, the wafer flattening effect during exposure is improved, so that the phenomenon that after photoetching is performed, the pattern loss and the lamination alignment performance are poor is avoided, and the product yield is increased.

The embodiment of the invention provides an automatic focusing method and device, and a mobile terminal. The method comprises: obtaining number of valid white spots in a focusing area corresponding todifferent focal lengths under a dark light and point light source environment, wherein pixel brightness values of the effective white spots are larger than or equal to a preset brightness threshold;and selecting a focal length corresponding to a focusing area with the least number of valid white spots in different focal lengths as a target focal length. Through adoption of the scheme, in a darklight environment, a focal length corresponding to a focusing area with the least number of valid white spots in different focal lengths as a target focal length, and a focal length corresponding to afocusing area with the least number of valid white spots is namely a spot focusing as clearly as possible, so that focusing accuracy is ensured, an out-of-focus phenomenon is avoided, and user shooting experience is improved.

The invention provides a pair of myopia prevention and treatment glasses for controlling a head position and a sitting posture, and relates to the technical field of glasses for correcting the bad sitting postures of students and preventing and treating the myopia of the students. The glasses are provided with a posture correction watching region and non watching regions, wherein the posture correction watching region is a through hole or a lens; the posture correction watching region is positioned on the lower part and / or the upper part of a horizontal vision line of a glasses frame; the nearest distance between the posture correction watching region and the horizontal vision line of the glasses frame is 0-22 mm; and other regions are the non watching regions. A wearer develops good learning and working eye-utilization habits by controlling the head position and the sitting posture, so that extremely good effects of suppressing, recovering and preventing the myopia can be achieved; bad postures such as wryneck, head drop, lookdown, strabismus and crouch down of the wearer can be well corrected; and multiple cervical vertebra relevant diseases can be prevented. The myopia prevention and treatment glasses are simple in structure and convenient to use, do not need any accessory devices, can prevent and treat the myopia and have a good effect and quick response. The myopia prevention and treatment glasses are particularly suitable for prevention, treatment and correction for the myopia of the youth.

The invention relates to a bellows of a rotating mirror framing camera, which comprises a bellows body and a rotating mirror, a relay lens array, an exit pupil diaphragm array and an image recording surface which are arranged in the bellows body. A secondary image I2 which is introduced from the outside of the bellows body is imaged on the rotating mirror and forms a final image on the image recording surface through the exit pupil diaphragms and the relay lenses after being mirrored by the rotating mirror; the image of an aperture diaphragm arranged on the bellows body is imaged on the exit pupil diaphragms through the rotating mirror; and the center of each exit pupil diaphragm is arranged on a cylindrical surface using a first Pascal helical line as an alignment line. By arranging the center of each exit pupil diaphragm on the cylindrical surface using the first Pascal helical line as the alignment line, constant scanning of the exit pupil diaphragm array is realized and the uniformity of the photographing frequency is ensured. The invention further discloses a technical scheme of respectively arranging the principal point of each relay lens in the relay lens array and the image recording surface on the cylindrical surfaces using a second Pascal helical line and a third Pascal helical line as alignment lines, thereby eliminating the theory error in the prior art and increasing the resolution of the camera.

The invention discloses an automatic pose adjustment method and device for a spherical optical element with a large curvature radius. According to the automatic posture adjustment method and device, ahigh-power microscope is utilized to collect a plurality of continuous dark-field gray-scale images focused to defocused correspondingly along four edge characteristic points with vertical and horizontal orthogonal diameters on the surface of the spherical optical element with the large curvature radius, an image Tenengrad operator value is calculated, the Tenengrad operator value and a high-power microscope axial movement curve are fitted, a positive focus position is searched according to an image Tenengrad operator extreme value criterion, and the spatial coordinates of each characteristicpoint are obtained; and by establishing a spatial mathematical model of the feature points and an adjusting device, the spatial coordinates of the four feature points are converted into pitch and spin two-dimensional adjustment amount to perform pose adjustment operations. The automatic posture adjustment method and device solve the defocusing problem caused by the non-parallel optical axis of the optical element and the optical axis of the microscope and the change of the rise height of the spherical optical element beyond the depth of field range of the microscope in the microscope full-aperture scanning detection process of the spherical optical element with large curvature radius.

The invention discloses a micro-impulse torsion device for differential measurement of laser interferometry, which solves the problems of low precision of torsion, defocus, and translation caused by impact force loading. Including the torsion part and the laser interference part; the torsion part includes a vertical frame, an upper cross bar and a lower cross bar, an oblique beam, a lifting adjustment mechanism and a translation adjustment mechanism; between the upper cross bar and the lower cross bar of the shaped frame The pendulum wire is suspended between the wires, and the middle part of the wire is fixed with a pendulum beam perpendicular to the wire. The vertical rod is fixed on the upper end of the inclined beam through the lifting adjustment mechanism. The lower end of the inclined beam is installed on the translation adjustment mechanism, and the translation adjustment mechanism is fixed on the test bench. ; The laser interference part includes beam expanders, reflectors, beam splitters, He-Ne lasers for generating interference beams, photodetectors and signal processing terminals. The measuring range of the device system of the invention is reasonable, the measurement accuracy is higher, the measurement process period is short, and the high-precision laser micro-pulse measurement is realized.

The invention discloses a projector intelligent focusing design method based on ultrasonic ranging. A DMD (Digital Micromirror Device) ray machine is internally provided with an MCU control chip, an ultrasonic ranging module and a focusing motor; one end of the focusing motor is connected with a focusing rod; through detecting a projection distance, the ultrasonic ranging module calculates and obtains the number of steps to be rotated by the focusing motor; and through controlling the motor driving chip, the MCU control chip enables the motor to drive the focusing rod on the DMD ray machine to rotate, and thus, focusing on the DMD ray machine can be completed. According to the projector intelligent focusing design method based on ultrasonic ranging, the cost needed for ultrasonic ranging is low, the system can avoid error operation caused due to vibration or object occlusion during the ranging process through a de-interference technology, the system adjusts the step size to be rotated by motor control through detecting the environment temperature in the case of work, a ray machine apparent focus problem caused by thermal expansion and contraction can be avoided, and the projection picture of the ray machine is kept distinct.

The invention discloses a photoetching process method. The photoetching process method comprises the following steps: 1, an optimal focal length and a focusing depth of exposure in a photoetching process are calculated; 2, a first photoresist is applied to a first wafer, wherein the thickness of the first photoresist is greater than the focusing depth; 3, exposure for multiple times is carried outfrom the bottom of the first photoresist, wherein each time of exposure before the last-time exposure is to process a sub-layer with the thickness of DOF in the first photoresist, the sub-layers aresuperposed sequentially from the bottom to the top of the first photoresist, the superposition thickness of the sub-layers is smaller than the thickness of the first photoresist, the remaining topmostsub-layer is formed at the top of the first photoresist, the thickness of the topmost sub-layer is smaller than or equal to the DOF, and the topmost sub-layer is processed through the last-time exposure; and 4, the first photoresist is developed. The focusing depth of the thick photoresist process can be increased, and the resolution and the process window are improved.

The invention belongs to the field of holography, and particularly relates to a precision positioning device and method of a dry plate for laser holographic direct printing. The precision positioning device of the dry plate comprises a light source, an expanded beam collimating lens, a flat reflector, a spatial light modulator, an aperture diaphragm, a double telecentric lens, a manual digital display translation stage, a scissor-type lifting platform, a standard test dry plate, a holographic dry plate clamping part, a two-dimensional angle precision regulator, a displacement platform, a CCD camera and a computer, wherein the standard test dry plate and the holographic dry plate clamping part are specially processed and manufactured; and the precision positioning method of the dry plate comprises the steps of observing a diffraction image of the spatial light modulator by using the CCD camera; cooperatively adjusting the two-dimensional angle precision regulator, the manual digital display translation stage and the scissor-type lifting platform according to certain order and method; and finally ensuring that the distance between the dry plate and the double telecentric lens is within a clear imaging range of the lens. The defocus phenomenon caused during laser holographic direct printing is avoided and the printing and reappearing effects of a hologram are improved.

The invention discloses an image recognition method and device based on multiple focal lengths and a storage medium. The image recognition method comprises the steps of acquiring multiple sample images with different focal lengths; respectively carrying out target identification on each sample image to obtain identification information of each detection target in each sample image; and performingduplicate removal processing according to the identification information of each detection target in each sample image, and storing the detection targets after duplicate removal into a preset multi-focus image target set. According to the technical scheme, all detection targets can be effectively recognized without multi-focus reconstruction of the sample images, so that the accuracy of image recognition can be improved, the image processing speed can be increased, the time required for recognition can be shortened, and the practical performance of a medical detection device can be improved.

The invention discloses a novel focusing non-blur lens module. A fixed mounting seat comprises a mounting seat base and a mounting seat sleeving part; the periphery of the mounting seat sleeving partis sleeved with an outer waveform elastic piece and an outer adjusting ring; the upper end part of the mounting seat sleeving part is provided with a cover plate; a mounting seat accommodating cavityof the fixed mounting seat is embedded with a lens frame; the core part of the lens frame is provided with a lens frame accommodating cavity; the lower end part of the inner wall of the lens frame accommodating cavity is provided with a lens frame flange; a spring located at the upper end side of the lens frame is also embedded in the mounting seat accommodating cavity; the lens frame accommodating cavity is internally embedded with an inner waveform elastic piece and a lens sleeve, and the lens sleeve is spinned in the lens frame; a focusing driving assembly is arranged beside the outer adjusting ring on the mounting seat base; the outer circumference of the lens frame is provided with a guiding piece; and the guiding piece passes through the sleeving part guiding hole in the mounting seat sleeving part and is inserted in an adjusting ring slope hole in the outer adjusting ring. Through the above structure, the novel focusing non-blur lens module has the advantages of novel structuredesign, good stability and reliability and high focusing precision, and a blur phenomenon can be effectively avoided.

The invention discloses an automatic device for evaluating the performance of a large-area surface enhanced Raman substrate, which comprises a Raman detection light path module, a control module, a clamping module and a data processing module, and the Raman detection light path module comprises a Raman probe for emitting a laser and detecting a sample substrate; the control module comprises a processor, an electric sliding table, a position sensor and a spectrograph; andthe electric sliding table can achieve relative movement of the sample substrate and the Raman probe in the X direction, theY direction and the Z direction. The automatic device disclosed by the invention can be used for evaluating the performance of the large-area surface-enhanced Raman substrate, and is applicable to various substrates such as glass, silicon wafers, paper, plastic and other flexible substrates; andaccording to the invention, large-area multi-point detection can be carried out, an automatic focusing function is also realized, defocusing in a mobile scanning process is prevented, and the accuracy of a detection result can be ensured.

The embodiment of the invention discloses an automatic focusing method and apparatus for a mobile terminal and the mobile terminal. The method includes the steps of determining a first spot light source determining condition when a focusing event is triggered, and the current focusing area is detected to be in a preset scope on the periphery of a screen, wherein the first spot light source determining condition is less restrict than a second spot light source determining condition corresponding to the focusing area outside the preset scope on the periphery of the screen; determining whether the current shot objected is a spot light source according to the first spot light source determining condition, and executing corresponding focusing operation according to the determining result. When the technical scheme is adopted, the probability of mistakenly determining a spot light source as a non-spot light source is reduced. The scheme of the mobile terminal determining whether a shot object is a spot light source in an automatic focusing process is optimized, focusing accuracy is ensured, defocusing phenomenon is prevented, and the user experience is improved.

The embodiment of the invention discloses an automatic focusing method and apparatus and a mobile terminal. The method includes that when a focusing event is triggered, and determining a first spot light source determining condition if a camera is detected to be on a first position, wherein the first position is the corresponding position where the surface of the camera faces downwards and the and included angle between the surface of the camera and the vertical surface exceeds a preset angle threshold, the first spot light source determining condition is less restrict than a second spot light source determining condition, and the second spot light source is located at the position outside the first position with respect to the camera. The method further includes determining whether the current shot objected is a spot light source according to the first spot light source determining condition, and executing corresponding focusing operation according to the determining result. When the technical scheme is adopted, the determination process of the mobile terminal on whether a shot object is a spot light source in an automatic focusing process is optimized, focusing accuracy is ensured, defocusing phenomenon is prevented, and the user experience is improved.

The invention discloses a CNC laser engraving integrated machine tool. The CNC laser engraving integrated machine tool comprises a main frame, a machining head, a protective cover and a device bin; the main frame is a frame defined by a metal structure; a machining table is arranged at the bottom of the main frame; a ball screw is arranged within the scope of an area defined by the main frame andis fixedly connected to the opposite side walls of the main frame; a C-shaped groove is formed in the back side of the machining head, and the machining head is arranged on the ball screw through theC-shaped groove, can move along the ball screw and comprises a spindle motor; the spindle motor clamps a tool; the machining head further comprises a laser module; and the laser module is arranged onthe side wall of a clamping part of the motor in parallel and is used for positioning and engraving.

The invention provides pipeline inner wall three-dimensional acquisition equipment, which comprises a body and an impeller, wherein the body comprises a rotating device, and the rotating device is provided with an image acquisition port; an image acquisition port used for importing the images of the inner wall of the pipeline into the image acquisition device; an image acquisition device used foracquiring images of the inner wall of the pipeline; the advancing speed of the scanning equipment, the rotating angular speed of the rotating device and the field angle of the image acquisition device meet the following relation: (theta-beta) * v is smaller than m * R * sin beta * w, v is the advancing speed of the scanning equipment in the rotating process of the rotating device, R is the radiusof the pipeline, beta is the half field angle of the image collecting device, w is the rotating angular speed of the rotating device, theta is the included angle of the optical axes of every two adjacent cameras, and m is a coefficient. Three-dimensional acquisition equipment without extra power is proposed for the first time. In order to ensure the synthesis effect of subsequent three-dimensional images, the advancing speed of scanning equipment and the rotating speed of image acquisition are limited, and optimization is performed according to experience, so that the three-dimensional synthesis can give consideration to the speed and the effect at the same time.

The invention belongs to the technical field of towel production and particularly relates to a bamboo fiber towel drying device. Aiming at the problem of low drying efficiency caused by small contactarea of towels and hot air, the scheme is put forward and includes that the device comprises an open-side-up outer drum in a drum structure, a waterproof tank is arranged in the bottom middle of the outer drum, a rotating disc is rotationally connected with the top end of the waterproof tank, supporting rods are distributed at equal intervals at the top end of the rotating disc, a same fixing ringis fixed to top ends of the supporting rods, and four to eight clamping devices are uniformly distributed at the top end of the fixing ring; a hydraulic lifting rod is fixed to the outer wall of theouter drum, an open-side-down C steel crossbeam is fixed to the top end of an extension rod of the hydraulic lifting rod, and a cover plate is fixed to the bottom end of a telescopic pipe which is fixed to the lower surface of the end of the C steel crossbeam. The bamboo fiber towel drying device has advantages that rhythmic shifting drying of surfaces of the towels attached to the supporting rodscan be realized, and probable scorching caused by direct irradiation of the surfaces of the towels by a traditional drying device can be avoided.

The present invention discloses a camera focus control device. The camera focus control device comprises a camera frame, a main tube and a camera frame regulation ring, a camera frame screw thread portion is arranged at the periphery of the front end of the camera frame, the camera frame is in threaded connection with the camera frame regulation ring through the camera frame screw thread portion,the camera frame and the camera frame regulation ring sleeve the internal portion of the main tube, a first stop piece is arranged between the camera frame and the main tube to restrict the camera frame to move back and forth only relative to the main tube in an axial direction, a second stop piece is arranged between the camera frame regulation ring and the main tube to restrict the camera frameregulation ring to rotate in a circumference only relative to the main tube, a main tube screw thread portion is arranged at the periphery of the tail end of the main tube, the main tube is in threaded connection with a camera adapter ring through the main tube screw thread portion, when focus is regulated, the main tube keeps still relative to the camera adapter ring, and the camera frame regulation ring is employed to allow the camera frame to move back and forth in an axial direction relative to the main tube to regulate the focus. The camera focus control device is compact in structure andsimple, convenient and rapid in assembling, reduces the manufacturing cost and is convenient and stable in focus control, and a threaded pitch between the camera frame regulation ring and the cameraframe can be flexibly selected according to an actual demand.

The invention discloses a long-focus optical lens. The lens comprises a first lens with double-convex positive focal power, a second lens with double-concave negative focal power, a third lens with double-convex positive focal power, a fourth lens with double-convex positive focal power, a fifth lens with double-concave negative focal power, a sixth lens with double-convex positive focal power, a seventh lens with double-concave negative focal power an eighth lens with double-convex positive focal power, and a ninth lens with double-concave negative focal power which are sequentially arranged from an object plane to an image plane, each lens is a glass spherical lens, the first lens, the second lens and the third lens are glued to form a first lens group, the fourth lens and the fifth lens are glued to form a second lens group, the sixth lens and the seventh lens are glued to form a third lens group, the eighth lens and the ninth lens are glued into a fourth lens group, and the overall focal length of the lens is larger than the total optical length. The lens can effectively correct aberration, improves imaging quality, has larger clear aperture and focal length compared with a lens of the same type, and realizes high-quality telephoto imaging.