Abstract: An apparatus for use in image display, of projecting a light beam onto a retina of a viewer, to thereby allow the viewer to perceive an image, is disclosed. The apparatus is constructed to include: a light emitter emitting a light beam; a scanner scanning the light beam emitted by the light emitter; an optical system receiving the light beam scanned by the scanner as an incoming light beam, and emitting the received incoming light beam as an outgoing light beam, such that, upon modulation of the light beam with respect to a traveling direction of the light beam, the outgoing light beam is directed to a pupil of the viewer; and a curvature compensator compensating a wavefront curvature of the incoming light beam.

Abstract: Disclosed is an illumination system for illuminating a surface to be illuminated, with light from a light source, the illumination system including a first optical integrator having a plurality of lens groups, for forming a plurality of first secondary light sources by use of light from the light source, a second optical integrator for forming a second secondary light source by use of light from the first secondary light sources, a first collecting optical system for superposing light from the first secondary light sources on a light entrance surface of the second optical integrator, a second collecting optical system for superposing light from the second secondary light source on the surface to be illuminated, and a driving mechanism for moving at least one of the plurality of lens groups translationally along a plane perpendicular to an optical axis, whereby the telecentricity of light illuminating the surface to be illuminated can be adjusted.

Abstract: A position detection apparatus for detecting a position of an object to be observed, including a position detection system, and an evaluation unit for measuring by the position detection system each of mark spacings between a plurality of alignment marks arranged on the object to be observed and evaluating measurement performance of the position detection system on the basis of mark spacing information obtained as the measurement result.

Abstract: An optical apparatus including an image forming optical system having a movable optical element, and a driving mechanism. A first block obtains a linear evaluation value by normalizing, by a first tolerance, an aberration expressed by a linear function of a position of the movable optical element and normalizing, by a second tolerance, an aberration expressed by a quadratic function of the position out of the aberrations of the optical system. A second block obtains a minimum value of a dummy variable by linear programming. A third block determines a position of the optical element to be moved by the driving mechanism using a value prepared by adding a relaxation amount to the minimum value obtained by the second block and minimizes the weighted sum of the quadratic evaluation values by adjusting the weights assigned to the quadratic evaluation values and a relaxation amount.

Abstract: A lens meter for measuring optical characteristics of a subject lens to be measured includes at least three light sources for measurement, a projecting lens which projects measurement light bundles from the light sources onto the subject lens placed on a projecting-lens optical axis, a diaphragm having an aperture disposed at an anterior focal point of the projecting lens between the light sources and the projecting lens, and a two-dimensional photodetector photo-receiving the light bundles passing through the subject lens after passing through the aperture of the diaphragm and the projecting lens without the use of an image forming optical system, and the projecting lens is disposed so that the light sources is conjugate with the photodetector in a case where the subject lens with a specific diopter in the vicinity of 0D or a frequently-used specific diopter is placed on the optical axis.

Abstract: A fluid dispenser dispenses a fluid alternately from one of a pair of ports (29,31) that are provided on opposite ends of a syringe (26) by moving a piston (42) back and forth inside the syringe. A pair of stirrers (47,48) are provided in the syringe on opposite axial sides of the piston. The stirrers may each individually rotate on an axis that extends in parallel with the moving direction of the piston. A pair of stirrer driving rings (49,50) are mounted on an outer periphery of the syringe in correspondence with the stirrers. Magnets (55,56,59,60) are embedded in the stirrers and the stirrer driving rings such that the stirrer is rotated by magnetic fields that are generated from the stirrer driving ring, as the stirrer driving ring is rotated by a motor (51,52).

Abstract: Fluid immersion technology can be utilized to increase the resolution and angular range of existing metrology systems. An immersion fluid placed between the metrology optics and the sample can reduce the refraction at the sample interface, thereby decreasing the spot size of the beam on a feature of the sample while simultaneously increasing the angular range of the system. The decreased spot size, in combination with an increased angular spread, allows an existing metrology system to measure parameters of a sample, such as a semiconductor or microelectronic device, with improved resolution and without expensive and/or complex changes to the mechanics of the metrology system.

Abstract: A lens meter obtaining 0D-reference-coordinates of target-images not detected in a reference state and measuring even progressive lenses, has a lens rest, an optical system having an optical axis, a light source, measurement targets and a photo-sensor, a part calculating optical characteristics based on coordinates-change of target-images in a measurement state with the lens on the rest and axis from those in a reference state without the lens thereon, and an information memory.

Abstract: A reticle having a test pattern for measurement of an optical characteristic of a projection optical system has a pattern adapted so that a high frequency component of a spectrum at a pupil plane of the projection optical system is reduced or suppressed. Illumination light is projected to the test pattern of the reticle in one direction or plural directions, and positions of images of the test pattern, formed by the projections in the plural directions, are detected and, based thereon, the optical characteristic of the projection optical system is measured.

Abstract: An H-shaped test key layout for exclusively monitoring 3-foil lens aberration effects during the fabrication of deep-trench capacitor memory devices is disclosed. The COMA lens aberration effect that used to occur along with the 3-foil lens aberration effect is now eliminated by this test key layout.

Abstract: An optical device inspection system and method employing a narrow aperture on a magnifying objective lens in order to reduce the circle of confusion and increase the depth of field. The smaller aperture resulting in an increase in depth of field allows for simultaneous focus for all portions of objects being inspected. An arc lamp with an elliptical reflector in combination with a condenser lens focuses a more intense beam of light through the objective lens, thereby providing sufficient brightness without sacrificing any depth of field.

Abstract: An electronic imaging apparatus includes a connecting section connected to an optical apparatus; an optical element having a preset transmittance with respect to light in a preset wavelength region, incident from the optical apparatus; and an electronic image sensor receiving the light transmitted through the optical element.

Abstract: A test system and a related method to perform optical and electrical tests, to adjust the focus and to seal the lens of digital fixed-focus cameras have been achieved. Said test system is especially suited for miniature camera module to be built into consumer electronic devices as mobile phones, PDAs, etc. Said test system comprises three parts, a control system, an auto-focus head, and a XYZ robot. Said auto-focus head executes the adjustment of the focus, identifies hot pixels and black level, tests the saturation level, identifies cold pixels, tests dust particles and white, blue, red, and infrared color levels. As last step the auto-focus applies glue to fix the focused lens of the camera module. Said XYZ robot performs is moving the camera modules to be tested in XY direction and is approaching the lens system of the auto-focus head in Z direction. Said control system has interfaces to both, XYZ robot and auto-focus hand and is comprising interfaces and a frame grabber.

Abstract: In a method according to one embodiment of the invention, aberrations in a lithographic apparatus are detected by printing a test pattern having at least one degree of symmetry and being sensitive to a particular aberration in the apparatus, and using a scatterometer to derive information concerning the aberration. The test structure may comprise a two-bar grating, in which case the inner and outer duty ratios can be reconstructed to derive information indicative of comatic aberration. Alternatively, a hexagonal array of dots can be used, such that scatterometry data can be used to reconstruct dot diameters indicative of 3-wave aberration.

Abstract: An optical system for an automatic lens meter for measuring the refractive power of a lens to be examined.

Abstract: Methods for the determination of center of focus and process control for a lithographic tool. Diffraction signatures are obtained from a plurality of diffraction structures located within multiple different focus setting fields. Variability of diffraction signatures with each field are determined, by direct analysis or comparison to a library. The variation or uniformity may be represented by any measure, including the standard deviation or the range of values of a chosen feature of a library of theoretical diffraction structures or the variability or uniformity of the diffraction signatures themselves, such as by RMS difference or intensity range. The methods may be used for process control and monitoring of focus drift by determining intra-field variation of diffraction signatures of multiple diffraction structures in a series of wafers.

Abstract: A method of correcting aberrations in an optical system by applying a light adjustable aberration conjugator layer to a component of the system, determining the nature of the aberration, applying radiation to the conjugator layer such as to change the refraction and/or shape of the conjugator layer to compensate for the aberration, and locking in the desired optical property.

Abstract: A method of optimizing a process for use with a plurality of lithography systems.

Abstract: Methods for determination of parameters in lithographic devices and applications by cross-section analysis of scatterometry models, including determination of center of focus in lithography devices and applications. Control methods are provided for process control of center of focus in lithography devices utilizing cross-section analysis.

Abstract: Multidirectional retroreflectors and methods of reflecting light beams from multiple directions are provided. The multidirectional retroreflectors utilize a four-mirror retroreflector with a common virtual reflection point.

Abstract: A measuring apparatus for irradiating measuring light and for measuring optical performance of a target optical system includes a barrel for housing the target optical system, the barrel being rotatable around an optical axis of the target optical system, and an illumination optical system for introducing the measuring light into the barrel, the illumination optical system being movable along a direction perpendicular to the optical axis of the target optical system, wherein the measuring apparatus controls an illumination area of the measuring light in the target optical system using a polar coordinate determined by a rotational angle of the barrel and a moving amount of the illumination optical system.

Abstract: A projection lens distortion error map is created using overlay targets and a special numerical algorithm. A reticle including an array of overlay targets is exposed several times onto a photoresist coated silicon wafer using a photolithographic stepper. After exposure, the overlay targets are measured for placement error. The resulting overlay error data is then supplied to a software program that generates a lens distortion error map for the photolithographic projection system.

Abstract: A method and system for measuring the temporal response of a micromirror array to a variety of driving signals. A micromirror array is illuminated with a coherent light source so that a diffraction pattern is reflected from the micromirror array. One or more photodetectors are aligned with spots of light in the diffraction pattern that correspond to orders of the diffraction pattern. Diffraction pattern theory predicts that the intensity of these spots of light will vary as the tilt angle of the micromirrors is changed. Thus, by measuring the relative intensity of the spots of light as the micromirror array is provided with a variety of driving signals, many performance characteristics of the micromirror array can be measured. Some of these characteristics include the impulse response, the forced resonant frequency (i.e. the natural frequency), the damped resonant frequency, the quality factor of the micromirror response, the damping factor of the micromirror response, and the frequency transfer function.

Abstract: Apparatus and method for measuring an optical imaging system, and detector unit. The measuring apparatus contains an arrangement for combining wavefront and distortion measurements. For this purpose, respectively associated interferometry and Moiré structures can be introduced on the object side and image side. The detector unit contains a fiber plate and/or a flexible image conductor with a curved entry surface or with at least two different entry surfaces, which are offset axially or inclined spatially with respect to each other, or with an axially movable entry surface. By way of suitable wavefront acquisition in various lateral positions of object and/or image structure, a topographic calibration of the object or image structure can be carried out.

Abstract: Iterative algorithm methods and systems for slope or gradient-type data is presented for wavefront zonal estimation of regular and irregular pupil shapes. The methods and systems bears universal wavefront estimation matrices that are directly applicable to any pupil shape without the need to set up new matrices. The algorithm consists in first extending the sampling pupil to a larger regular square shape and second extrapolating the sampled slope data outside of the sampling pupil employing Gerchberg-type iterations. Unbiased least-squares wavefront estimation is then performed in the square domain. Results show that the RMS deviation error of the estimated wavefront from the original wavefront can be less than ?/150 after about twelve iterations and less than ?/100 (both for ? equal 632.8 nm) within as few as five iterations.

Abstract: A lens meter having a measurement optical system including a light-emitting optical system, emitting a measurement luminous flux to an eyeglass lens, and a light-receiving optical system having a light-receiving element, receiving the measurement luminous flux passing through the eyeglass lens, an eyeglass holding device between the light-emitting and light-receiving systems, and an arithmetic control circuit computing characteristics of the lens based on receiving element output. The holding device includes a lens receiver supporting the lens, and an eyeglass sandwiching unit, which sandwiches the eyeglasses. The lens receiver is freely movable between the measurement optical path of the measurement optical system and a withdrawal position outside the path, and is moved in the withdrawal position after the eyeglasses have been sandwiched by the sandwiching unit.

Abstract: Characterization of an optical system is quickly and easily obtained in a single acquisition step by obtaining image data within a volume of image space. A reticle and image plane are positioned obliquely with respect to each other such that a reticle having a plurality of feature sets thereon, including periodic patterns or gratings, is imaged in a volume of space, including the depth of focus. Metrology tools are used to analyze the detected or recorded image in the volume of space through the depth of focus in a single step or exposure to determine the imaging characteristics of an optical system. Focus, field curvature, astigmatism, spherical, coma, and/or focal plane deviations may be determined. The present invention is particularly applicable to semiconductor manufacturing and photolithographic techniques used therein, and is able to quickly characterize an optical system in a single exposure with dramatically increased data quality and continuous coverage of the full parameter space.

Abstract: The invention automates determination of the quantity of a index matching liquid.

Abstract: When actual measurement data of a wavefront aberration of a projection optical system is input, a main controller calculates a targeted image forming characteristic of the projection optical system based on the data and a Zernike sensitivity table of the image forming characteristic that is made prior to the input. By using the Zernike sensitivity table, the targeted image forming characteristic can be calculated with only one measurement of wavefront aberration. Moreover, parameters that denote a relation between an adjustment of an adjustable specific optical element and a change in the image forming characteristics of the projection optical system is obtained in advance, and are stored in advance in a storage unit.

Abstract: An object pattern is imaged by an imaging system onto the image plane of the imaging system at a location where a reference pattern suited to the object pattern is situated in order to measure the imaging fidelity of an optical imaging system, for example, an eyeglass lens, a photographic lens, or a projection lens, for use in the visible spectral range. The resultant, two-dimensional, superposition pattern is detected in a spatially resolved manner in order to determine imaging parameters therefrom. The object pattern is generated with the aid of at least one electronically controllable pattern generator that serves as a self-luminous, electronically configurable, incoherent light source and may, for example, have a color monitor. The measuring system allows rapidly, flexibly, checking optical imaging systems with minimal time and effort spent on the mechanical setup required.

Abstract: An optical write-in head for obtaining a clear image even in printing at a relatively high recording density without generating strip-like irregularities in most cases. The optical write-in head applies light carrying image information to a photosensitive substance. The optical write-in head includes an array light source having a plurality of dot light sources each of which selectively emits the light corresponding to the image information, and a lens array facing the array light source. The lens array has a plurality of lens elements which corresponds to the plurality of dot light sources respectively. An angular aperture ? of each of the lens elements is set in a range of about 14° to 18°.

Abstract: Test patterns and a method for evaluating and adjusting the resolution of an electron beam lithography tool. The test patterns include multiple feature patterns that are repeated throughout the test pattern. Each feature pattern can be interleaved with horizontal and/or vertical line patterns that facilitate cleaving of a test substrate for three dimensional analysis of the developed image. Further, each feature pattern can comprise multiple sub-patterns. Each sub-pattern includes at least one feature having a size that varies from less than a nominal resolution limit of the lithography tool to greater than the nominal resolution limit. The lithography tool resolution can be evaluated by exposing a test pattern on a resist coated substrate, and analyzing the developed image.

Abstract: A method of obtaining particulars or characteristics of an ophthalmic lens by detecting a fluorescent light which is emitted from the ophthalmic lens upon exposure to an excitation light (UV light). The particulars or characteristics of the ophthalmic lens include, for instance, identifying marks such as characters, figures, symbols, etc. which are formed in the ophthalmic lens to identify the ophthalmic lens, a thickness of the ophthalmic lens such as a contact lens and an intraocular lens, and an angular position of the ophthalmic lens, particularly of a special contact lens having circumferential portions having respective different thickness values.

Abstract: A device for calculating diffraction efficiencies of a diffraction lens divided into a plurality of regions, each region comprising at least one grating ring, comprises a first memory for storing information about diffraction efficiencies of the regions; a second memory for storing information about weights corresponding to the regions; and a first processor for retrieving information from the first and the second memory, and calculating diffraction efficiencies of the entire diffraction lens using the formula E j = ? m = 1 M ? W m ? ? mj ( 1 ) wherein: j: integer indicating the order of diffraction light Ej: diffraction efficiency for j-th order diffraction light of the diffraction lens M: positive integer (M>1) indicating the number of regions for which the diffraction efficiency is calculated m: index of the region for which the diffraction efficiency is calculated ?mj: diffraction efficiency for the j-th order diffraction light of the m-th region (stored in the first m

Abstract: A fluid dispenser dispenses a fluid alternately from one of a pair of ports (29,31) that are provided on opposite ends of a syringe (26) by moving a piston (42) back and forth inside the syringe. A pair of stirrers (47,48) are provided in the syringe on opposite axial sides of the piston. The stirrers may each individually rotate on an axis that extends in parallel with the moving direction of the piston. A pair of stirrer driving rings (49,50) are mounted on an outer periphery of the syringe in correspondence with the stirrers. Magnets (55,56,59,60) are embedded in the stirrers and the stirrer driving rings such that the stirrer is rotated by magnetic fields that are generated from the stirrer driving ring, as the stirrer driving ring is rotated by a motor (51,52).

Abstract: The invention uses optics and precision mechanisms to quantitatively assess the performance of medical endoscopes. By viewing standardized optical targets under well-controlled conditions, the optical quality of endoscopes can be easily determined in much the same fashion as getting one's eyes tested at the optometrist. The actual design, however, is much more complicated than your optometrist's eye chart and different types of endoscopes from different manufacturers require customization of the target geometry, the viewing distance, and the viewing angle. Also, there are several optical characteristics beyond image sharpness that need to be assessed, requiring other unique test geometries, including contrast, distortion, and vignetting. Clinically significant measurements are performed with simplicity and cost-effectiveness through the use of relatively inexpensive optical components and an embedded processor and graphical display system.

Abstract: In the case of a method and a measuring system for measuring the distortion of an optical imaging system with the aid of moiré patterns, an object grating with an object pattern is arranged in the object plane of the imaging system, and an image grating with an image pattern is arranged in the image plane of the imaging system. Both the object pattern and the image pattern in each case have a multiplicity of cells with sub-gratings of different grating properties, it being possible, in particular, for the sub-gratings to have different directions of periodicity and different phase angles.

Abstract: A position detection method of illuminating an object to be observed with an illumination system having a variable illumination condition to detect a position of the object to be observed by a position detection system, including the steps of measuring each of mark spacings between a plurality of alignment marks arranged on the object to be observed, and selecting the illumination condition on the basis of mark spacing information obtained as the measurement result.

Abstract: Characterization of an optical system is quickly and easily obtained in a single acquisition step by obtaining image data within a volume of image space. A reticle and image plane are positioned obliquely with respect to each other such that a reticle having a plurality of feature sets thereon, including periodic patterns or gratings, is imaged in a volume of space, including the depth of focus. Metrology tools are used to analyze the detected or recorded image in the volume of space through the depth of focus in a single step or exposure to determine the imaging characteristics of an optical system. Focus, field curvature, astigmatism, spherical, coma, and/or focal plane deviations may be determined. The present invention is particularly applicable to semiconductor manufacturing and photolithographic techniques used therein, and is able to quickly characterize an optical system in a single exposure with dramatically increased data quality and continuous coverage of the full parameter space.

Abstract: The present invention generally relates to a method and system for determining the position and alignment of a plane in relation to an intersecting axis and using that known position and alignment to allow for corrections to be made when using the plane as a reference plane. More particularly, the invention relates to a method and system for determining the angle of tilt of a planar surface in relation to a laser beam, and using the determined angle of tilt to calculate a correction factor to be applied to the laser beam. Briefly stated, the method and system ultimately calculates a correction factor, z-offset, that is applied when using the laser beam in a procedure.

Abstract: In an optical characteristic measuring method for measuring an optical characteristic of a projection optical system (10a), a reticle (9) having a plurality of patterns (TP) is supplied, and scattered light from an aperture is directed to the plurality of patterns (TP), whereby light beams are projected onto the plurality of patterns in mutually different directions, by which images of the plurality of patterns are formed through the projection optical system (10a). Positions of images of the plurality of patterns, respectively, are detected and, by use of the result of detection, the optical characteristic of the projection optical system is detected. This accomplishes an optical characteristic measuring method and a reticle to be used therefor, which are suitable for measuring an optical characteristic of an optical system such as wavefront aberration, for example, at high precision.

Abstract: A lens meter for measuring optical characteristics of a lens, which is capable of measuring a progressive lens easily and an aspherical lens accurately. The lens meter is provided with a lens rest having an aperture, for placing a lens thereon, a measurement optical system having a light source which projects a measurement light bundle onto the lens placed on the lens rest and a photodetector which receives the measurement light bundle transmitted through the lens, for forming a plurality of different measuring positions inside the aperture, calculation means for obtaining optical characteristics at each of the measuring positions based on an output from the photodetector, comparison means for comparing the optical characteristics obtained at the measuring positions, and guiding means for guiding a predetermined one of the measuring positions to at least one of a near viewing section and a far viewing section of a progressive lens based on a result of the comparison.

Abstract: There is here disclosed a method for inspecting an exposure apparatus, comprising illuminating a mask, in which a mask-pattern including at least a set of a first mask-pattern and a second mask-pattern mutually different in shape is formed, from a direction in which a point located off an optical axis of an exposure apparatus is a center of illumination, and exposing and projecting an image of the mask-pattern toward an image-receiving element, and measuring a mutual relative distance between images of the first and second mask-patterns exposed and projected on the image-receiving element, thereby inspecting a state of an optical system of the exposure apparatus.

Abstract: A method of measuring aberration of a projection optical system. The method includes the steps of imaging a test pattern through the projection optical system, and measuring a potential deviation amount of the image of the test pattern and measuring aberration of the project optical system on the basis of the positional deviation amount. The measuring step includes a process of determining a coefficient of a particular Zernike term and a process of changing a position or a shape of a region on a pupil plane of the projection optical system before light from the test pattern passes therethrough, in accordance with the particular Zernike term.

Abstract: A lens meter according, including: a unit body provided with eyeglasses support means for supporting eyeglasses; a left measurement optical system provided in the unit body and provided with a left light-emitting optical system that emits measurement light to a left eyeglass lens of the eyeglasses and a left light-receiving optical system that receives the measurement light passing through the left eyeglass lens with a CCD (light-receiving element); a right measurement optical system provided in the unit body and provided with a right light-emitting optical system that emits measurement light to a right eyeglass lens of the eyeglasses and a right light-receiving optical system that receives the measurement light passing through the right eyeglass lens with the CCD (light-receiving element); and an arithmetic control circuit that performs operation to the optical characteristics of a pair of the eyeglass lenses based on an output of the CCD (light-receiving element).

Abstract: A method for diagnosing a lithographic tool. The method includes developing digitalized images of at least one wafer pattern with different exposure doses and assembling the digitized images into a pupilgram. The at least one function is of a known illuminator behavior of the lithographic tool is modeled. The pupilgram is fitted to the modeled function to determine whether a behavior associated with the pupilgram is within predetermined limits of illuminator behavior to diagnosis imperfections in the illuminator behavior. One technique applied to the illuminator analysis consists of evaluating the dose transmitted (by direct calculation) by the lens for a given input pupilgram (or set of pupilgram basis functions), a given pattern size and pitch, and a defined lens NA, is described.

Abstract: A system for determining response characteristics, insertion loss and group delay, of an optical component by applying a sweeping wavelength optical signal that is modulated with an RF signal, measuring the insertion loss and group delay at a series of wavelengths and correlating the measurements to wavelengths. A method for synthesis of an effective modulation frequency in determining the group delay response characteristics of an optical component by obtaining a series of measurements over a sample optical spectrum using a given modulation frequency and calculating a weighted average of the group delays in the series of measurements giving a result substantially equivalent to a measurement taken using a modulation frequency equal to the effective modulation frequency.

Abstract: A laser beam emitted from a laser source is split by a beam-splitting means such as a beam sampler, and the power Q of the split beam is measured by a first detector. In addition, the power q1 of light that has passed through a pinhole while a DOE is not set is measured by a second detector, and the power ratio ?=q1/Q is calculated. Then, the DOE is set and the power ratio ?k=qk/Q, where qk is the power of each light beam, is calculated. The power ratio ?k is evaluated on the basis of the power ratio ?, so the optical properties of a diffractive optical element, in particular, in terms of diffraction efficiency in laser-beam diffraction and intensity uniformity of split beams can be measured with high accuracy.

Abstract: A refractive power measuring method is disclosed wherein a pattern plate 8 is disposed at a certain position in a measuring optical path in a measuring optical system 1, a measuring light emitted from a measuring light source 5 is received by a photosensor 9 through the pattern plate 8, a soft contact lens TL is disposed at a certain position in the measuring optical path, and a change of a pattern light received by the photosensor 9 is obtained to determine optical characteristic values of the soft contact lens.

Abstract: A progressive-power lens can be properly evaluated based on optical performance values of which definition methods are not unified, such as progressive zone length and addition diopter. In addition to commodity product specifying information 11a which specifies a trade name of a lens 9, progressive zone length specifying information 11b which specifies length of a progressive zone of the lens, material refractive index specifying information 11c which specifies a material refractive index of the lens, and addition diopter specifying information 11d which specifies addition diopter of the lens, definition method specifying information 11e is inscribed on the progressive-power lens 9. The definition methods of the aforesaid progressive zone length and the addition diopter are specified by the definition method specifying information 11e.

Abstract: RNA enzymes or ribozymes can act as endoribonucleases, catalyzing the cleavage of RNA molecules with a sequence specificity of cleavage greater than that of known ribonucleases and approaching that of the DNA restriction endonucleases, thus serving as RNA sequence specific endoribonucleases. An example is a shortened form of the self-splicing ribonsomal RNA intervening sequence of Tetrahymena (L-19 IVS RNA). Site-specific mutagenesis of the enzyme active site of the L-19 IVS RNA alters the substrate sequence specificity in a predictable manner, allowing a set of sequence-specific endoribonucleases to be synthesized. Varying conditions allow the ribozyme to act as a polymerase (nucleotidyltransferase), a dephosphorylase (acid phosphatase or phosphotransferase) or a sequence-specific endoribonuclease.