65results about How to "Reduce coma" patented technology

An optical system for use in an optical pickup apparatus comprises a first optical surface having a superposition type diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each ring-shaped zone is composed of a plurality of stepped sections stepwise, and a second optical surface having a diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each of the plurality of ring-shaped zones are divided by a stepped section to generate a diffractive light ray of diffractive order whose absolute value is not small than 1 for the light flux.

The invention relates to a refraction and reflection type large aperture and large field of view imaging system. The refraction and reflection type large aperture and large field of view imaging system is characterized in that a refraction type correction plate, a reflection type primary mirror and a refraction type correction mirror group are successively arranged along an optical axis from the outside to the inside; the central area of the second surface of the correction plate is plated with a reflective coating layer, and becomes a reflection type secondary mirror; an incident light beam irradiates to the reflection type primary mirror through the refraction type correction plate; the reflection type primary mirror reflects the incident light beam to the reflection type secondary mirror; and the reflection type secondary mirror reflects the light beam to the refraction type correction mirror group, and then the light beam passing through the refraction type correction mirror group is converged on a focal plane of an optical system. The refraction and reflection type large aperture and large field of view imaging system sets the refraction type correction plate within the focus of a reflection type spherical main mirror and takes the central area of the second surface of the correction plate as the reflection type secondary mirror and the diaphragm, thus having the advantages of ultra-short lens barrel and large field of view, and being able to be widely applied to the astronomy, aviation, security and protection, and other photoelectric imaging fields. The refraction and reflection type large aperture and large field of view imaging system can realize aberration reducing design for a 11DEG-15DEG field of view. However, the field of view for a traditional refraction and reflection type imaging system is only 3DEG-4DEG.

An optical pickup includes: first and second objective lenses focusing light beams of different wavelengths on first and second optical discs having different thickness protection layers; a coma aberration generating unit generating coma aberration in the light beams; a collimating lens between a light source and the first objective lens; and a collimating lens driving unit. The protection layer thickness of the plastic first optical disc is smaller than that of the second optical disc. The first objective lens satisfies a lens tilt coma aberration sensitivity of 0 to 0.3[λrms/°]. An optical axis of the light beam approximately coincides with an optical axis of the first objective lens. The optical pickup is inclined to the optical disc so that initial coma aberration with respect to the first optical disc is optimally corrected. The coma aberration generating unit is used for obtaining optimal reproducing environment when reproducing the second optical disc.

The invention provides an ellipsoidal reflector perifocus high-precision positioning device and method, and belongs to the optical confocal microscopy technical field and optical precise measurement field. The device is formed by a lower light path for ellipsoidal reflector apofocus high-precision positioning and an upper light path for ellipsoidal reflector perifocus high-precision positioning. The method is characterized by, to begin with, carrying out ellipsoidal reflector apofocus positioning through the lower light path; and then, carrying out ellipsoidal reflector perifocus positioning through the upper light path. The device and method, to begin with, by making full utilization of the special feature of ellipsoidal reflector bifocus conjugation, provide a technological means for ellipsoidal reflector perifocus positioning, and then, realize ellipsoidal reflector perifocus high-precision positioning through an imaging technological means; and the device and method provide the technological means for a precise-adjustment ellipsoidal reflector to reduce coma and astigmatism of the ellipsoidal reflector, and play a promotion role in application and development in the optical confocal microscopy technical field and the optical precise measurement field.

The invention provides an optical imaging lens. The optical imaging lens sequentially comprises, from an object side to an image side along an optical axis, a first lens, a second lens, a third lens with positive focal power, wherein the image side surface of the third lens is a convex surface, a fourth lens with positive focal power, a fifth lens, a sixth lens, and a seventh lens with negative focal power, wherein half of the maximum field-of-view semi-FOV of the optical imaging lens meets the following condition: Semi-FOV is greater than 70 degrees and less than 90 degrees; the maximum value Namx of the refractive indexes of the first lens to the seventh lens meets the condition that Namx is greater than 1.7; the air interval T34 between the third lens and the fourth lens on the optical axis, the air interval T45 between the fourth lens and the fifth lens on the optical axis and the central thickness CT4 of the fourth lens on the optical axis meet the following condition: (T34 + T45)/CT4 is greater than 0.5 and less than 1.0; and the effective focal length f1 of the first lens and the effective focal length f4 of the fourth lens meet the condition that f4/f1 is greater than -1.0 and less than -0.5. The problem that an optical imaging lens in the prior art is poor in optical performance is solved.

An optical pickup includes: a light source emitting a beam having a predetermined wavelength; a plastic objective lens condensing the emitted beam on an optical disc; a light detector receiving and detecting the beam reflected by the optical disc; an objective-lens driving unit driving the objective lens in the tilt direction to tilt the objective lens; and a tilt-sensitivity sensing unit sensing a tilt sensitivity denoted by ΔW_LT/Δθ, where ΔW_LT [λrms] is a coma aberration amount Δθ [deg] is a tilt amount at the time of tilting the objective lens, wherein, in the case where the sensed tilt sensitivity is equal to or larger than a predetermined value, tilt is corrected by tilting the objective lens so that signal quality detected by the light detector is improved, and in the case where the sensed tilt sensitivity is smaller than the predetermined value, tilt is not corrected.

The invention discloses a Cassegrain telescope adjustment mechanism and adjustment method, and the mechanism comprises a laser which is used for emitting a light beam to a primary mirror of a Cassegrain telescope, a rotating mechanism which is used for driving the laser to rotate around the optical axis of the primary mirror, and a light receiving part which is vertically disposed on the optical axis of the primary mirror. The optical axis of emergent light of the laser is parallel to the optical axis of the primary mirror, and the light receiving part can move in the direction of the opticalaxis of the primary mirror. When the Cassegrain telescope is adjusted, the optical axis of laser emitted by the laser emitter is parallel to the optical axis of the primary mirror, one end of the backsurface of the primary mirror is provided with a group of light receiving parts, a rotary laser and a movable light receiving part, and the change of the circle center and the diameter of a circle formed by a plurality of projection points on the light receiving parts at different positions is compared. The distance and the inclination angle between the primary mirror and the secondary mirror areadjusted, the influence of spherical aberration, coma, defocusing and other aberrations is reduced, and the measuring equipment is simple in structure, does not need to use an interferometer and is convenient to operate.

A method for compensating the coma aberration in a pickup of a recording and reproducing device that records or reproduces data on or from an optical disc using the pickup is provided. The method includes a first coma aberration compensating step to compensate coma aberration in a body of an optical system including an objective lens for emitting a light beam to an optical disc including a plurality of recording layers and a second coma aberration compensating step to compensate coma aberration caused by relative inclination of the optical system with respect to the optical disc.

An objective lens actuator includes a plurality of objective lenses, a first lens holder on which the plurality of objective lenses are mounted, and a drive mechanism that drives the first lens holder. At least one of the plurality of objective lenses is mounted on the first lens holder while being held by the second lens holder. Formed on the second lens holder are a slide part which slides the second lens holder with respect to the first lens holder at a time of assembly, and a projection arranged outward of the slide part and protruding toward the first lens holder with the second lens holder being mounted on the first lens holder. The lens holder has a groove formed therein where the projection is securely adhered.

The invention discloses a near-infrared fluorescence spectrophotometer based on a miniature scanning grating micromirror. The near-infrared fluorescence spectrophotometer comprises a detection chamber, a fluorescence excitation module and a near-infrared fluorescence splitting and spectrum obtaining module, rapid acquisition of near-infrared full-spectrum information is realized by integrating the scanning grating micromirror, a three-dimensional full spectrum of a measured substance can be obtained within one minute by combining with the fluorescence excitation module, and the influence of coma can be effectively reduced by the fluorescence excitation module; a plano-convex cylindrical mirror in the near-infrared fluorescence splitting and spectrum acquisition module is utilized to ensure the imaging quality of near-infrared fluorescence spectrum, aberration caused by an optical system in the fluorescence spectrum information acquisition process is greatly reduced, the spectral resolution and the signal-to-noise ratio are improved, near-infrared spectrum information detection is realized by utilizing a single-tube detector, the spectrum information acquisition speed is ensured, the structure of an optical system is simplified, the cost is reduced, and the system has the advantages of modularization, miniaturization, wide spectrum, high resolution, high signal-to-noise ratio, low cost, high detection speed and the like.

The invention discloses a high-precision positioning device and a high-precision positioning method for a far focus of an ellipsoidal reflector. The high-precision positioning device and the high-precision positioning method belong to the field of optical confocal microscopic technologies and optical precise measurement. The high-precision positioning device comprises a lapping optical path which is composed of optical elements such as laser devices, and further comprises an ellipsoidal reflector and the like. The high-precision positioning method comprises the steps of firstly, conducting effective imaging by means of an image sensor, then adjusting a six-degree-of-freedom workbench, acquiring a series of intensity information and roundness information of a light spot, merging the information into an evaluation function, establishing a degree-of-freedom and evaluation function table, finding out an extreme value of the evaluation function and a degree of freedom corresponding to the extreme value in the degree-of-freedom and evaluation function table, and finally adjusting the six-degree-of-freedom workbench according to the degree of freedom corresponding to the extreme value such that a focus of a focusing objective lens coincides with the far focus of the ellipsoidal reflector. The high-precision positioning device and the high-precision positioning method fully utilize the special property of the bifocal conjugation of the ellipsoidal reflector, and realize precise positioning of the ellipsoidal reflector through providing a technological means for positioning the far focus of the ellipsoidal reflector by utilizing the imaging light spot information.