155results about How to "Reduce astigmatism" patented technology

A system and method of treating target tissue in a patient's eye, which includes generating a light beam, deflecting the light beam using a scanner to form first and second treatment patterns, delivering the first treatment pattern to the target tissue to form an incision that provides access to an eye chamber of the patient's eye, and delivering the second treatment pattern to the target tissue to form a relaxation incision along or near limbus tissue or along corneal tissue anterior to the limbus tissue of the patient's eye to reduce astigmatism thereof.

An optical image lens system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. The first lens element with positive refractive power has a convex object-side surface. The second lens element and the third lens element have positive refractive power. The fourth lens element has refractive power. The fifth lens element with positive refractive power is made of plastic and has a convex object-side surface and a concave image-side surface, wherein at least one surface thereof is aspheric. The sixth lens element with refractive power is made of plastic and has a concave image-side surface, wherein at least one surface thereof is aspheric, and the image-side surface thereof changes from concave at a paraxial region to convex at a peripheral region.

A noncontact laser microsurgical apparatus and method for marking a cornea of a patient's or donor's eye in transplanting surgery or keratoplasty, and in incising or excising the corneal tissue in keratotomy, and for tissue welding and for thermokeratoplasty. The noncontact laser microsurgical apparatus comprises a laser source and a projection optical system for converting laser beams emitted from the laser source into coaxially distributed beam spots on the cornea. The apparatus further includes a multiple-facet prismatic axicon lens system movably mounted for varying the distribution of the beam spots on the cornea. In a further embodiment of the method of the present invention, an adjustable mask pattern is inserted in the optical path of the laser source to selectively block certain portions of the laser beams to thereby impinge only selected areas of the cornea.

A progressive ophthalmic lens element having a front surface that includes an upper viewing zone having a surface power suitable for distance vision, a lower viewing zone having a surface power suitable for near vision, and a corridor of relatively low astigmatism connecting the upper and lower viewing zones, the corridor being a part of an intermediate viewing zone having a surface power varying from that of the upper viewing zone to that of the lower viewing zone. The progressive ophthalmic lens element also has a back surface. The invention is then characterized by the front surface including at least one correction to improve optical performance of the lens element by at least partially compensating for a cylinder correction applied to, or to be applied to, the backsurface.

An electronic device includes at least one optical lens assembly. The optical lens assembly includes four lens elements, and the four lens elements are, in order from an outside to an inside, a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element has an outside surface being convex in a paraxial region thereof. The second lens element has an inside surface being convex in a paraxial region thereof. The fourth lens element has an inside surface being concave in a paraxial region thereof, wherein at least one of an outside surface and the inside surface of the fourth lens element includes at least one critical point in an off-axis region thereof.

This invention discloses a laser diode pump all solid state ultraviolet pulse laser, the pump light output by coupling optic fiber, the pump light focused the pump end face of laser crystal through pump end face membrane to form plane reflection mirror, the laser crystal generating excited fluorescent radiation after absorbing pump light energy, the fluorescent forming base frequency light beam by oscillation in resonant cavity, laser incident to plane concave mirror by plane reflection mirror through laser crystal, sound and light Q adjusting crystal, plane color separation mirror, sum-frequency crystal and double frequency crystal, the plane color separation mirror leading light from resonant cavity, the focusing by lens, refracting by quartz prism and leading out laser by ultraviolet reflection mirror. Said invention has compact structure, high average output pulse power and large adjustable range of pulse recurrent frequency etc advantages.

The invention provides a deflecting system for deflecting a charged particle beam from a first direction to a second direction, the deflecting system comprising a first deflector for deflecting said charged particle beam off the first direction within a first deflection plane; a second deflector for deflecting the deflected charged particle beam into the second direction within the first deflection plane; and at least one deflect pair of correcting coils comprising two correction coils which are positioned and shaped t reduce an astigmatism of the charged particle beam caused by the deflections.

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 scanning device for scanning a dual-layer optical record carrier with dual orthogonally polarized radiation beams. The device having a spherical aberration compensation optical subsystem including a switchable liquid crystal cell of birefringent material for altering different optical paths lengths provided by a phase structure of stepped annular zones.

A scanning laser operation system for the thermo-shaping operation of cornea on living body is composed of a scanning laser source, an adaptive locating system, a safte parameter testing system, a therapeutic effect testing system, and a controller.

The invention discloses a vehicle-mounted camera lens, which comprises, in order from the object side to the image side, a first lens having a negative focal power, a convex object side surface and aconcave image side surface; a second lens having a negative focal power, a concave object side surface and a convex object side surface; a third lens having a positive focal power and double convex surfaces; a diaphragm; a fourth lens having a positive focal power and double convex surfaces; a fifth lens having a negative focal power and a concave object side surface, and forming a cemented lens with the fourth lens; a sixth lens having a positive focal power and a convex object side surface; and a filter. The second lens, the third lens, the fourth lens, and the fifth lenses are all glass spherical lenses, and the first lens and the sixth lens are glass aspherical lenses. The vehicle-mounted camera lens significantly increases the distortion of the lens in a small angle of view to meet the special algorithm requirements of the vehicle system; and the lens size and length of the lens are effectively controlled while improving the resolution of the entire lens.

The invention discloses an eyepiece system and a head-mounted display device. The eyepiece system a spherical display screen and a Fresnel lens which are sequentially arranged along the incident direction of light; the center line of the spherical display screen is overlapped with a horizontal line where the optical axis of the Fresnel lens is located; the spherical display screen protrudes towards the Fresnel lens; and the Fresnel lens is provided with a first surface protruding towards a light path diaphragm and a second surface protruding towards the spherical display screen. According to the eyepiece system provided by the technical schemes of the invention, a Fresnel lens and spherical display screen-combined technical means is adopted; the surface shapes of the Fresnel lens are reasonably set, so that the focal power of the eyepiece system can be shared, and the astigmatism of the system can be reduced; and the spherical display screen is set reasonably, so that the curvature of field of the system can be decreased, and edge imaging quality can be improved.

A light-emissive module (114), typically utilizing one or more LEDs (132R, 132G, and 132B), is configured so that the maximum intensity of the module's light emission occurs along a direction (138) materially non-perpendicular to the back surface (136) of the module's supporting body (130). An active image-generating screen (102) contains a plurality of block facets (112), each containing a plurality of the light-emissive modules arranged so that their maximum light-intensity directions are largely the same. The block facets are configured to approximate a curved surface. The maximum light-intensity directions (158) of the block facets are thus materially slanted to one another. The image-generating screen presents a video image. A display system suitable for a motion simulator, such as a flight simulator, is formed by combining the screen with a reflective collimator (104).

An intraocular lens is provided that includes a refractive element and a mask. The refractive element has a first power in a first meridian and a second power greater than the first power in a second meridian. A magnitude of the first and second powers and a location of the first and second meridians are configured to correct astigmatism in a human eye. The mask is configured to block a substantial portion of light from passing through an annular region thereof and to permit a substantial portion of light to pass through a central aperture thereof to enhance an astigmatism correction rotational misplacement range and depth of focus.

The invention relates to an optical path structure of a small echelle grating spectrometer. The structure includes a condenser lens, an incident pinhole, a collimating lens, an echelle grating, a cross dispersion prism, a focusing lens, a cylindrical lens and an area-array detector; the collimating lens and the focusing mirror are spherical mirrors; the condenser lens makes an incident light beam focused to the incident pinhole; a light beam emitted from the incident pinhole irradiates the collimating lens; a parallel light reflected by the collimating lens directly is directly incident to the surface of the echelle grating; a light beam diffracted by the echelle grating irradiates the focusing lens through the reflection of the cross dispersion prism; and a focused light reflected by the focusing lens is received by the area-array detector after the achromatic treatment of the cylindrical lens. The optical path structure can be used for effectively balancing the contradiction between the high resolution and the small size of a conventional grating spectrometer and realizing the high spectral resolution with the structure of the small size and has the advantages of compact structure, small size, light weight, no moving parts, simultaneous measurement of wide spectral bands and the like.

The invention discloses a method for reducing the astigmatism of a progressive additional lens, and provides an overall astigmatism optimization method. The method comprises the following step of: adding initial rise distribution data to new rise distribution data of a freedom surface to obtain lens surface shape rise distribution data subjected to astigmatism optimization. After an initial progressive additional lens is optimized by the method provided by the invention, the maximum astigmatism of the lens is reduced by 14.3 percent. In the method, according to a curvature definition in differential geometry, each point is added with a corresponding freedom surface which is related to the minimum curvature and consists of micro cylindrical surfaces so as to reduce the astigmatism of each point, and the direction of each micro cylindrical surface is consistent with the minimum curvature direction of the point; therefore, by the method, the maximum astigmatism of the surface of the lenscan be effectively reduced, the distinct range of a vision far zone is enlarged, and the refraction capacity of a user in an effective vision zone is improved.