Abstract: The invention relates to an artificial ophthalmic lens (20) containing an anterior optical surface (21) and a posterior optical surface (22), at least one of which contains a multifocal optical diffractive profile (25). A cross apodized profile part (25?) is formed on the diffractive profile (25) wherein phase shifting elements (27) are provided alternately forming the elements of a decreasingly apodized series (40) and an increasingly apodized series (41) in such a way that the decreasing and increasing elements of the two series (40, 41) form envelope curves that meet at a common intersection point (45). The invention further relates to a method for the production of such an artificial ophthalmic lens (20).

Abstract: The invention relates to a trifocal artificial ophthalmic lens (20), which contains an anterior side optical surface (21), a posterior side optical surface (22) and an optical axis (23), at least one of the anterior side optical surface (21) and the posterior side optical surface (22) contains an optics having three useful focal points and having an at least partially diffractive profile. The three useful focal points correspond to focal points (31, 32) belonging to the 0th and 1st diffraction orders of the diffractive profile, and to a focal point (33) belonging to an enhanced diffractive secondary peaks between the 0th and the 1st diffraction orders. The invention also relates to a method of producing the aforementioned trifocal artificial ophthalmic lens.

Abstract: The invention relates to a trifocal artificial ophthalmic lens (20), which contains an anterior side optical surface (21), a posterior side optical surface (22) and an optical axis (23), at least one of the anterior side optical surface (21) and the posterior side optical surface (22) contains an optics having three useful focal points and having an at least partially diffractive profile. The three useful focal points correspond to focal points (31, 32) belonging to the 0th and 1st diffraction orders of the diffractive profile, and to a focal point (33) belonging to an enhanced diffractive secondary peaks between the 0th and the 1st diffraction orders. The invention also relates to a method of producing the aforementioned trifocal artificial ophthalmic lens.

Abstract: Visual acuity of a subject is ascertained by displaying to the subject sets of symbols having a different size, recording the subject's responses identifying each symbol, calculating a rate of recognition for each symbol size, and determining the client's visual activity based on the rate of recognition.

Abstract: The object of the invention relates to an artificial ophthalmic lens (20) that contains an anterior optical surface (21) and a posterior optical surface (22), where the anterior optical surface (21) and the posterior optical surface (22) have a common optical axis (23), and at least one of the anterior optical surface (21) and the posterior optical surface (22) is a multifocal optics (24) that at least partly has a multifocal optical diffractive profile (25). A cross apodized profile part (25?) is formed on the diffractive profile (25), in other words phase shifting elements (27) are provided on the diffractive profile (25) that alternately form the elements of a decreasingly apodized series (40) and an increasingly (reversed) apodized series (41) in such a way that the decreasing and increasing elements of the two series (40, 41) form envelope curves that meet at a common intersection point (45).

Abstract: The invention relates to a method for measuring visual acuity of a subject, said method comprising the steps of providing a set of optotypes, providing a pre-calculated value of similarity for pairs of optotypes selected from the set of optotypes, displaying to the subject sub-sets of optotypes of the set of optotypes in different optotype size, receiving for each displayed optotype of one of said sub-set of optotypes of a given optotype size a response of the subject indicative of an optotype (identified optotype) selected from the set of optotypes, registering for each response a value of similarity corresponding to the pre-calculated value of similarity of the pair of optotypes consisting of the displayed optotype and the identified optotype indicated in the response, calculating a value of rate of recognition for each optotype size, the value of rate of recognition for a given optotype size being an average of the registered values of similarity for the responses to the optotypes displayed in the given

Abstract: In clinical visual acuity measurements a method a system and a device for measuring visual acuity of a client is provided. In accordance with the implementation, the system comprises a display device (41), an input device (42) and a computing device (43). The display device (41) is capable of displaying sets of symbols in different size to the client. The input device (42) is capable of receiving responses of the client indicative to the identity of the symbols, and the computing device (43) is capable of a) registering (S431) values to the responses belonging to pre-calculated values of similarity of the symbols, b) calculating (S432) a rate of recognition value for each symbol size, and c) determining (S433) the measured visual acuity from the rate of recognition values.

Abstract: A holographic storage system for reading a hologram stored on a holographic storage medium. The system comprises: storage medium holding means; a spatial light modulator (SLM) for encoding a reference beam with a code pattern; a detector; and a servo control unit for determining a misalignment of the reference beam and the storage medium from the detected image and for acting upon the SLM to shift the code pattern. A method of reading a hologram stored on a holographic storage medium comprising: a) encoding a reference beam with a code pattern created by a spatial light modulator (SLM); b) detecting an image of the reconstructed hologram; c) determining a misalignment of the reference beam and the storage medium from the detected image; and d) shifting the code pattern on the SLM based at least in part on the misalignment.

Abstract: The invention relates to a method for reading a Fourier hologram recorded on a holographic storage medium with a holographic storage system. The method comprises the steps of: —calculating a characteristic value from a detected image of a reconstructed Fourier hologram in at least two relative positions of a reference beam and said storage medium, each of the characteristic values being indicative of a misalignment of the reference beam and said storage medium at the respective relative position, —calculating a servo value from the measured characteristic values, —determining an aligned relative position of said reference beam and said storage medium by means of a predetermined servo function using the calculated servo value, —setting the relative position of the reference beam and said storage medium to said aligned relative position, and—detecting an image at said aligned relative position.

Abstract: The object of the invention is a phase modulator system comprising a beam splitter and a reflection mode phase modulator suitable for modulating linearly polarised light of at least one specific polarisation state while maintaining said polarisation state. The beam splitter and the phase modulator are arranged along an optical path of a light beam. The beam splitter is a polarisation beam splitter and the phase modulator system further comprises an optical rotator being arranged along the optical path between the polarisation beam splitter and the phase modulator, and rotating the polarisation state of the light beam by 45° in a given sense, wherein the polarisation state of the light beam incident upon the phase modulator corresponds to said specific polarisation state.

Abstract: The invention relates to a holographic storage system for reading a hologram stored on a holographic storage medium. The system comprises: storage medium holding means arranged along an optical path of a reference beam; a spatial light modulator (SLM) arranged along said optical path for encoding a reference beam with a code pattern; a detector for detecting an image of the reconstructed hologram; and a servo control unit for determining a misalignment of said reference beam and said storage medium from the detected image and for acting upon said SLM to shift said code pattern.

Abstract: The invention relates to a method for reading a Fourier hologram recorded on a holographic storage medium with a holographic storage system. The method comprises the steps of: —calculating a characteristic value from a detected image of a reconstructed Fourier hologram in at least two relative positions of a reference beam and said storage medium, each of the characteristic values being indicative of a misalignment of the reference beam and said storage medium at the respective relative position, —calculating a servo value from the measured characteristic values, —determining an aligned relative position of said reference beam and said storage medium by means of a predetermined servo function using the calculated servo value, —setting the relative position of the reference beam and said storage medium to said aligned relative position, and —detecting an image at said aligned relative position.

Abstract: There is disclosed a method and apparatus for coding data, for the purpose of preventing unauthorised readout of information. In the method, user information is converted into digital data (UD), and the digital data is recorded in a first data set (CD) and a second data set (HD), where the first data set (CD) is recorded in a first optical storage medium of a data carrier, and the second data set (HD), is recorded in a second, holographic storage medium of the data carrier. According to the method, the digital data (UD) is divided between the first and second data sets (CD,HD) in a manner so that a part of the user information is contained only in the first data set (CD), and another part of the user information is contained only in the second data set (HD), and the relative proportion of the user information in the data sets is selected so that the information contained in any one of the data sets is insufficient by itself to restore the complete user information (UD) contained in both data sets.

Abstract: The present invention relates generally to a method for parallel optical decoding of a digital phase image to an intensity image by algorithmic encoding of a data page into phase image and parallel optical decoding by capturing the interference of the phase data page and its copy shifted by one or a few pixels with respect to each other.

Abstract: The object of the invention is a high data density holographic data storage method. The holograms are written into the volumetric data storage layer or layers, and during the writing process the accurate places of holograms in the data carrier structure are determined by the intersection domain of the object and reference beam or beams, and during the reading process the selection of holograms simultaneously illuminated by the reference beam or beams, the read-out of the addressed hologram, and the suppressing of un-addressed holograms are carried out by a spatial filter located confocally with the addressed hologram and/or by satisfying the Bragg condition. The optical arrangement for recording and reading out holograms has three dedicated planes in confocal arrangements, where the addressed hologram is in the middle dedicated plane in the storage material, and in the two outer dedicated planes there are spatial filters. The optical arrangement is a 12f optical System consisting of three pairs of objectives.

Abstract: There is disclosed a method and apparatus for coding data, for the purpose of preventing unauthorised readout of information. In the method, user information is converted into digital data (UD), and the digital data is recorded in a first data set (CD) and a second data set (HD), where the first data set (CD) is recorded in a first optical storage medium of a data carrier, and the second data set (HD), is recorded in a second, holographic storage medium of the data carrier. According to the method, the digital data (UD) is divided between the first and second data sets (CD,HD) in a manner so that a part of the user information is contained only in the first data set (CD), and another part of the user information is contained only in the second data set (HD), and the relative proportion of the user information in the data sets is selected so that the information contained in any one of the data sets is insufficient by itself to restore the complete user information (UD) contained in both data sets.