53results about How to "Eliminate astigmatism" patented technology

A holographic laser scanners of ultra-compact and modular design capable of reading bar and other types of graphical indicia within a large scanning volume using holographic optical elements and visible laser diodes, and also a method of designing and operating the same for use in diverse applications.

The invention discloses a control device and method for achieving wide-range scanning of an electron beam and a additive manufacturing device capable of achieving the wide-range scanning of the electron beam. The control device comprises a negative electrode, a grid electrode, a positive electrode, a focusing coil, a deflecting coil, an anastigmatic coil and a DA converter, wherein the anastigmatic coil is used for generating anastigmatic magnetism which can produce an anastigmatic magnetic field to control the astigmatic degree. According to the control device, the current of the focusing coil can be changed to achieve good focusing of the electron beam; in addition, the current of the anastigmatic coil can be changed to remove astigmatism of the electron beam, and thus beam spots can remain high quality; in addition, the formation quality of electron beam selective melting additive manufacturing (3D printing) can be greatly improved, and particularly the precision and quality of printed large parts can be improved. The control method is high in operability, and enables high-quality scanning of the electron beam in any route and within a wide range.

The invention provides a method for testing the resolution of each imaging region of a digital camera. A camera to be tested is used for shooting resolution test plates to obtain photos, and the photos are treated according to the following steps: 1. converting into gray level images; 2. calculating the diameters of the photo images; 3. carrying out dark corner light loss correction; 4. carrying out binaryzation on the images; 5. dividing a plurality of pixel blocks to be used as foreground pixel blocks; 6. removing the foreground pixel blocks positioned at edges or corners of the photos or the foreground pixel blocks with too small area; 7. establishing a plurality of concentric circles for dividing the photo images into a plurality of annular regions; and calculating the astigmation of each annular region; and 8. calculating the relative astigmation and the resolution of each annular region in the photo images. The invention can determine the clear usable region of the photos shot by a set of camera equipment, and can also compare the resolution difference in different proportions between the whole shooting picture and the middle cut image, and the shooting method with the maximum resolution can be found, so the required shooting number is minimum on the premise that the resolution in the conversion is maximum or the resolution is ensured.

The invention is an IV-type concave holographic grating making process flow, belonging to the field of spectrum technique, relating a grating making process flow. And its technical solution comprises: substrate treatment, coating glue, front drying, holographic exposure, development, after drying, thermal melting, ion beam etching, cleaning, and plating. And it is novel, low-cost and easy to implement, especially replaces traditional reaction ion etching with photoresist thermal melting, largely reducing cost, and shortening making cycle, and it can reduce parts of system and eliminate astigmatism and coma of optical system.

The invention provides a method for visually testing the resolution of each imaging area of a digital camera, which comprises the following steps of: converting a photo into a gray level image; calculating the diameter of the image of the photo; performing vignetting glossiness loss correction; performing binaryzation on the image; marking a plurality of pixel blocks as foreground pixel blocks; removing the foreground pixel blocks from the corners of the photo or the foreground pixel blocks with small areas; by taking the centre of the image of the photo as the centre of a circle, establishing a plurality of concentric circles to divide the image of the photo into a plurality of circular areas and representing image divergence degrees in each circular area by using rectangular images; and according to neighboring relations of the circular areas, sequentially splicing all the obtained rectangular images into a test result graph. The method not only can determine a clear and available area of the photo shot by a set of shooting equipment, but also can compare the resolution of the fully-shot photo with that of middle screenshots of different ratios to find a shooting method through which maximum resolution can be realized, thereby ensuring that the definition in copying can be maximal or the number of the shot photos is the smallest on the premise of ensuring the definition.

Arrangements for the point-to-point imaging of a broad spectrum of electromagnetic radiation and ultrasound at large angles of incidence employ matched pairs of spherically bent reflectors to eliminate astigmatic imaging errors. Matched pairs of spherically bent crystals or spherically bent multi-layers are used for X-rays and EUV radiation; and matched pairs of spherically bent mirrors that are appropriate for the type of radiation are used with microwaves, infrared and visible light, or ultrasound. The arrangements encompass the two cases, where the Bragg angle—the complement to the angle of incidence in optics—is between 45° and 90° on both crystals/mirrors or between 0° and 45° on the first crystal/mirror and between 45° and 90° on the second crystal/mirror, where the angles of convergence and divergence are equal. For x-rays and EUV radiation, also the Bragg condition is satisfied on both spherically bent crystals/multi-layers.

The present invention provides a microscope objective lens. The microscope objective lens comprises 14 sheets of spherical lenses which are arranged in a coaxial mode. The 14 sheets of spherical lenses comprise in order from an object side to an image side: a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), a seventh lens (L7), an eighth lens (L8), a ninth lens (L9), a tenth lens (L10),an eleventh lens (L11), a twelfth lens (L12), a thirteenth lens (L13) and a fourteen lens (L14). The microscope objective lens obviously increasesthe view field of the object side while ensuring the high numerical aperture and the high resolution to achieve apochromatism from 500nm to 800nm, greatly eliminates spherical aberration, coma, astigmatism, field curvature, distortion, chromatic difference of magnification and axial chromatic aberration, meets the flat field apochromatism objective lens demand and achieves the technical demand ofa wide field of view (namely a large visual field number and a low range) and a high numerical aperture.

A holographic laser scanning system for producing a highly defined 3-D scanning volume for omni-directional laser scanning of bar code symbols therein having a minimum element width on the order of about 0.017 inches or less. The holographic laser scanning system comprise a housing, a plurality of laser sources, a holographic scanning disc and a plurality of photodetectors. The plurality of lasr sources are disposed within the housing, for producing a plurality of laser beams. The holographic scanning disc is disposed within the housing, and has a plurality of holographic optical elements for scanning the laser beams and producing a plurality of laser scanning planes for scanning a code symbol. Each laser scanning plane has predefined beam characteristics and is spatially confined within a highly-defined 3-D scanning volume having at least three focal zones, a depth of field of at least 10 inches, and a scanning volume of at least 1,440 cubic inches. The plurality of laser scanning planes intersect within the highly defined 3-D scanning volume and the predefined beam characteristics of the laser scanning planes cooperate within the highly defined 3-D scanning volume so as to produce an omnidirectional laser scanning pattern for omnidirectional scanning therewithin, code symbols having a minimum element width on the order of about 0.017 inches or less.

The invention relates to the technical field of optical imaging devices, and particularly discloses a camera lens, a camera module, electronic equipment and an automobile. The camera lens comprises afirst lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object side to an image side, wherein the first lens element has negativerefractive power, the second lens element has negative refractive power, the third lens element has positive refractive power. the fourth lens element has positive refractive power, the fifth lens element has negative refractive power, The sixth lens element has positive refractive power. The camera lens can directly keep small size and light weight without increasing the number of lens pieces, can keep good optical performance, and can well capture details of a shot object.

The bar code reading device comprises a shell, a groove-shaped view finding window with openings in the two ends, a camera module and a circuit board, the camera module and the circuit board are arranged in the shell, a hole is formed in the front face of the shell, and the groove-shaped view finding window is arranged in the hole in a sleeved mode; wherein the depth value D1 of the groove-shapedview finding window is greater than or equal to 10 mm, and the lens of the camera module collects a bar code image through the groove-shaped view finding window and then transmits the bar code image to a processor on the circuit board for decoding to obtain bar code information. According to the bar code identifying and reading device, through the deep groove-shaped view finding window and the fluctuation arranged on the side wall of the groove-shaped view finding window, stray light is effectively prevented from entering the lens, and therefore a clear bar code image is captured in a long distance.

The invention belongs to the medical appliance technical field and relates to a corneal cross-linking instrument. The corneal cross-linking instrument comprises a light source; the light source is installed at the upper part of a light source base; the middle of the light source base is provided with a light adjustment disk and a lens group; the lower part of the light source base is connected with a lens mounting seat; and the lower part of the lens mounting seat is provided with a lens. With the corneal cross-linking instrument of the invention adopted, stray light of a light beam can be eliminated, so that a light spot formed by a light beam emitted by the light source can be uniform, and the edge of the light spot is neat, and the size of the light spot is adjustable.

The invention provides a laser radar detection device. The device comprises a curved surface cover body, a laser, a first lens, a detector and a second lens. An emergent light beam of the laser is emitted to a measured object after passing through the first lens and the curved surface cover body in sequence to form a transmitting light path; the normal direction of the intersection point of the first optical axis of the first lens and the curved surface cover body coincides with the first optical axis; a reflected light beam reflected by the measured object sequentially passes through the cover body and the second lens and enters the detector to form a receiving optical path; and the normal direction of the intersection point of the second optical axis of the second lens and the curved surface cover body coincides with the second optical axis. According to the laser radar detection device provided by the invention, the first optical axis and the second optical axis are set to coincidewith the normal direction of the intersection point of each optical axis and the curved surface; the transmitting light path and the receiving light path are not influenced by the shape of the curvedsurface cover body, astigmatism of the transmitting light path and the receiving light path can be eliminated, the quality and the energy of light spots irradiated to a measured object by outgoing light beams are improved, and therefore, the light energy received by the detector and the detection performance of the laser radar are improved.

The invention discloses a varifocal optical system. The system sequentially comprises a first fixed lens group with positive focal power, a main zoom lens group with negative focal power, a diaphragm,a second fixed lens group with positive focal power, a focusing lens group with negative focal power, an auxiliary zoom lens group with positive focal power and an imaging surface from an object plane side to an image plane side; the auxiliary zoom lens groups are in one-to-one correspondence with the main zoom lens groups in position and move from the object side to the image plane side along the optical axis. The focusing lens group moves correspondingly to the position, the imaging wavelength, the temperature and the imaging object distance of the main zoom lens group along the optical axis, and the zoom is corrected and focused, so that stable imaging can be realized on an imaging surface in a focal length changing process. While 4K resolution, large aperture and infrared confocal performance are realized, the total length of the optical system is greatly shortened, the structure is more compact, and the popularization of 4K camera shooting is facilitated.