scispace - formally typeset
Search or ask a question

Showing papers on "Apochromat published in 1992"


Journal ArticleDOI
TL;DR: The reduced eye was further modified by changing the refracting surface to an aspherical shape to reduce the amount of spherical aberration, providing an improved account of both the longitudinal and transverse forms of ocular chromatic aberration.
Abstract: New measurements of the chromatic difference of focus of the human eye were obtained with a two-color, vernier-alignment technique. The results were used to redefine the variation of refractive index of the reduced eye over the visible spectrum. The reduced eye was further modified by changing the refracting surface to an aspherical shape to reduce the amount of spherical aberration. The resulting chromatic-eye model provides an improved account of both the longitudinal and transverse forms of ocular chromatic aberration.

297 citations


Journal ArticleDOI
TL;DR: A model of the fish lens with a polynomial gradient is proposed that yields spherical aberration, image quality and chromatic aberration similar to that reported for the fish.

74 citations


Patent
Kumagai Satoru1
09 Sep 1992
TL;DR: In this paper, a fluorescent confocal microscope was designed for the improvement of optical cutting function and lateral resolution and the improvement in the accuracy of quantitative measurement for a wide visual field.
Abstract: A fluorescent confocal microscope designed for the improvement of optical cutting function and lateral resolution and the improvement of the accuracy of quantitative measurement for a wide visual field. An intermediary optical system, which is arranged between a pair of scanner mirrors and an objective optical system (a pupil projection lens and an objective lens), is of a retrofocustype construction and it has chromatic aberration of magnification tending to cancel chromatic aberration of magnification of the objective optical system for wavelengths of excitation light and fluorescent light. The pupil of the objective lens is relayed to the vicinity of the scanner mirrors by the pupil projection lens and the intermediary optical system. In this case, a pupil magnification β p is selected to satisfy an expression |β p |≦1.

68 citations


Journal ArticleDOI
TL;DR: The analytical expression of the axial aberration coefficients of the cathode lens in combination with a focusing lens was derived and the values compared with those when only a single-polepiece lens was used as discussed by the authors.

25 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied the pulse propagation through the singlet lens, by solving the diffraction integrals, and several peculiar features around the focal plane are shown, which the geometrical optics approximation cannot predict.

22 citations


01 Oct 1992
TL;DR: Diffraction is responsible for one of the images formed by the Echelon bifocal lens, consistent with the theoretical prediction that the negative chromatic aberration of a diffractive contact lens should partially cancel the positive chromatic Aberration of the human eye.
Abstract: Although diffractive contact lenses have been well documented in theory, no definitive experimental data have been reported which confirm that the near image is in fact created by diffraction rather than by refraction. We have tested the diffraction hypothesis for one type of diffractive contact lens (the Hydron Echelon bifocal) experimentally by measuring its longitudinal chromatic aberration in isolation and when worn on the eye. The basis of this test is that, according to theory, diffractive lenses should have chromatic aberration which is opposite in sign to that measured for the eye. Objective measurements of chromatic aberration were made with a focimeter when the lens was in a wet cell. Subjective measurements were made with a Badal optometer when the lens was worn on the eye. Four control experiments were conducted to provide baseline measurements of the eye’s chromatic aberration, against which we compared the results obtained for the diffractive contact lens. The data were also compared with conventional measurements of refractive error obtained by standard subjective techniques and by an automated infrared refractor. Our results showed that the longitudinal chromatic aberration of the diffraction image of the Echelon bifocal lens was about one-half that obtained under the four control conditions: for the naked eye, for the nondiffraction image of the Echelon lens, or for either image of a refractive bifocal contact lens (CIBA Bisoft). These results are consistent with the theoretical prediction that the negative chromatic aberration of a diffractive contact lens should partially cancel the positive chromatic aberration of the human eye. Conversely, it would be difficult to explain these results on the basis of any other known technique for achromatizing the human eye. We therefore conclude that diffraction is responsible for one of the images formed by the Echelon bifocal lens.

14 citations


Journal ArticleDOI
TL;DR: In this article, the authors have tested the diffraction hypothesis for one type of diffractive contact lens (the Hydron Echelon bifocal) experimentally by measuring its longitudinal chromatic aberration in isolation and when worn on the eye.
Abstract: Although diffractive contact lenses have been well documented in theory, no definitive experimental data have been reported which confirm that the near image is in fact created by diffraction rather than by refraction. We have tested the diffraction hypothesis for one type of diffractive contact lens (the Hydron Echelon bifocal) experimentally by measuring its longitudinal chromatic aberration in isolation and when worn on the eye. The basis of this test is that, according to theory, diffractive lenses should have chromatic aberration which is opposite in sign to that measured for the eye. Objective measurements of chromatic aberration were made with a focimeter when the lens was in a wet cell. Subjective measurements were made with a Badal optometer when the lens was worn on the eye. Four control experiments were conducted to provide baseline measurements of the eye's chromatic aberration, against which we compared the results obtained for the diffractive contact lens. The data were also compared with conventional measurements of refractive error obtained by standard subjective techniques and by an automated infrared refractor. Our results showed that the longitudinal chromatic aberration of the diffraction image of the Echelon bifocal lens was about one-half that obtained under the four control conditions: for the naked eye, for the nondiffraction image of the Echelon lens, or for either image of a refractive bifocal contact lens (CIBA Bisoft). These results are consistent with the theoretical prediction that the negative chromatic aberration of a diffractive contact lens should partially cancel the positive chromatic aberration of the human eye.(ABSTRACT TRUNCATED AT 250 WORDS)

14 citations


Journal ArticleDOI
Masato Shibuya1
TL;DR: Considering the real pupil curvatures, a new exact sine condition in the presence of spherical aberration is derived and its validity is confirmed by ray traces.
Abstract: Considering the real pupil curvatures, a new exact sine condition in the presence of spherical aberration is derived and its validity is confirmed by ray traces. This sine condition is useful for lens design and lens evaluation.

14 citations


Patent
06 Jul 1992
TL;DR: A collimating lens system comprises a chromatic aberration correction element and a converging lens which has both surfaces formed of a convex aspherical surface as mentioned in this paper, and it is constructed of positive and negative lenses cemented to each other.
Abstract: A collimating lens system comprises a chromatic aberration correction element and a converging lens which has both surfaces formed of a convex aspherical surface. The converging lens has no aberrations except chromatic aberration. The chromatic aberration correction element has small refractive power adapted to correct a chromatic aberration of the converging lens, and the element is constructed of positive and negative lenses cemented to each other. The positive lens and the negative lens have almost the same refractive index, and have different dispersion.

12 citations


Journal ArticleDOI
TL;DR: An alternative method of aberration correction similar to that used in the catadioptric Schmidt system is presented, where a Wood lens with a parabolic-index profile is used to provide all or most of the optical power.
Abstract: Spherical aberration in a flat-surfaced radial gradient-index lens (a Wood lens) with a parabolic-index profile can be corrected by altering the profile to include higher-order terms. However, this results in a large amount of third-order coma. An alternative method of aberration correction similar to that used in the catadioptric Schmidt system is presented. A Wood lens with a parabolic-index profile is used to provide all or most of the optical power. Coma is corrected by stop shifting, and spherical aberration is corrected by placing a powerless Wood lens corrector plate at the stop.

10 citations


Patent
20 Nov 1992
TL;DR: In this paper, the authors proposed a high magnification apochromat microscope objective lens which has such a high numerical aperture as NA 1.4, and is constituted so that a spherical aberration, a chromatic aberration and a curvature of image can be corrected satisfactorily.
Abstract: PURPOSE:To provide the high magnification apochromat microscope objective lens which has such a high numerical aperture as NA1.4, and is constituted so that a spherical aberration, a chromatic aberration and a curvature of image can be corrected satisfactorily. CONSTITUTION:This lens is constituted of a first group G1 of a plano-convex lens or a plano-convex having the joining surface whose strong convex surface is turned to an image side, a second group G2 of positive refracting power, a third group G3 containing a cemented lens, a fourth group G4 containing a meniscus lens of positive refracting power whose convex surface is turned to an object side, a fifth group G5 of negative refracting power, and a sixth group G6 containing a cemented meniscus lens whose convex surface is turned to the image side, and when f5, f6 and (f) denote focal distances of a fifth group G5, a sixth group G6, and the whole system, respectively, this high magnification microscope objective lens satisfies the following conditions. (1): ¦f5/f¦ 15.

Journal ArticleDOI
TL;DR: The spherical aberration of eyes corrected with intra‐ocular lenses is investigated using a model eye with realistic levels of corneal asphericity and the results indicate that the aberration is intermediate between that of paraxial schematic eyes and real eyes.
Abstract: The spherical aberration of eyes corrected with intra-ocular lenses is investigated using a model eye with realistic levels of corneal asphericity. The results indicate that the aberration is intermediate between that of paraxial schematic eyes and real eyes. By using standard optical aberration theory, it is shown that for a plano-convex lens with the curved surface facing the cornea, the aberration is similar to that of normal phakic eyes and therefore probably too low to be of any clinical significance. However, for other lens orientations or designs, the level of aberration is usually higher and may lead to a refractive error varying with pupil size and a loss of acuity with large pupil diameters.

Journal ArticleDOI
TL;DR: By combining achromatic and superachromatic lens groups to achieve improved tertiary-spectrum residuals in apochromatic systems, the significance of a secondary spectrum and a tertiary spectrum in lens design is reviewed.
Abstract: By combining achromatic and superachromatic lens groups we may achieve improved tertiary-spectrum residuals in apochromatic systems. The application of this technique is reported. The significance of a secondary spectrum and a tertiary spectrum in lens design is also reviewed.

Patent
Laux Uwe1
09 Jan 1992
TL;DR: The apochromatic field lens collimator for a focal reductor system in Ritchey-Chretien-Cassegrain telescopes (RCC) is described in this paper.
Abstract: The apochromatic field lens collimator is for a focal reductor system in Ritchey-Chretien-Cassegrain telescopes (RCC). Along the optical axis of the optical surfaces of the RCC system, i.e. the surfaces of a correlation plate, a field lens is located at a distance (L1). The entry pupil of the collimator is the exit pupil of the RCC system. After a further air distance (12) is a further lens (L2), and beyond a further air distance (13) is a triple union group os lenses (L3,L4,L5). Beyond this union group, and after an air distance (14) is a thickner meniscus (L6). This is followed, after a lesser air distance (15) by a final triple union group of lenses (L7,L8,L9). The optical glass used is of the chrome or quartz type, whilst the two union groups of lenses are composed of a material combination of optical glass and earth alkaline fluoride optical glass. USE - For the focal reductor system of an RCC telescope.

Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the performance of an off-axis curved holographic lens using a numerical ray-tracing procedure to eliminate spherical aberration in the Gaussian image plane.
Abstract: This paper evaluates the performance of an off-axis curved holographic lens using a numerical ray-tracing procedure The hologram curvature has been suitably selected to eliminate spherical aberration Light intensity distribution in the aberration spot observed at the Gaussian image plane has been evaluated for different object fields The images of extended coherent and incoherent edge as well as bar objects have been computed and the results compared with that for the aberration-free case All the results are illustrated in graphical form

Journal ArticleDOI
TL;DR: In this article, the imaging of extended objects by a holographic lens in the presence of third-order spherical aberration and astigmatism has been carried out, and the results have been compared with that for the aberration-free case.
Abstract: Investigations on the imaging of extended objects by a holographic lens in the presence of third-order spherical aberration and astigmatism have been carried out. Light intensity distribution in the aberration spot observed at the Gaussian plane has been evaluated numerically, using a ray-tracing procedure, for different amounts of astigmatism and for a fixed value of spherical aberration. The images of extended coherent and incoherent edges as well as bar objects have been computed and the results have been compared with that for the aberration-free case. All the results are illustrated in graphical form.

Patent
12 Jun 1992
TL;DR: In this article, a biconcave lens of short flint glass between two collecting lenses of heavy crown glass is used for remote sensing of the Earth or other planets, with a field of view of at least plus or minus 20 deg.
Abstract: The meniscus lens element (1) on the object side has only a low refractive power (negative or positive) and is formed of three components, including a biconcave lens of short flint glass between two collecting lenses of heavy crown glass An iris (2) separates it from another three component meniscus lens element (3) which divides the image plane and is matched to the focal surface The structure affords sufficient refractive power for fully apochromatic performance USE/ADVANTAGE - For remote sensing of the Earth or other planets, an extremely compact lens of high resolution in the 400 to 1000 nm wavelength range covers a field of view of at least plus or minus 20 deg

Patent
07 Sep 1992
TL;DR: In this article, the relative opening of 3.5 and focal length of 35 mm with a rear shutter, the object-side lens component (L1, L2) being constructed as a composite lens.
Abstract: of EP0537469The lens provided for photographic compact cameras and having the relative opening of 3.5 and the focal length of 35 mm is of the triplet type with a rear shutter, the object-side lens component (L1, L2) being constructed as a composite lens. Four conditions the chromatic coma and the chromatic astigmatism are specified in order to obtain an exceptionally compact design and a balanced monochromatic correction, as well as to reduce the chromatic difference in magnification.

01 Jan 1992
TL;DR: In this paper, the light intensity distribution in the aberration spot observed at the Gaussian plane has been evaluated numerically, using a ray tracing procedure, for different amounts of astigmatism and for B fined value of spherical aberration.
Abstract: SUMMARY : lnvcstigiltions on the imaging of extended objects by a holographic lens in the presence of third-order spherical aberration and astigmatism have been carried out in this paper. Light intensity distribution in the aberration spot observed at the Gaussian plane hils been evaluated numerically, using a raytracing procedure. for different amounts of astigmatism and for B fined value of spherical aberration. The images of extended coherent and incoherent edge as well as bar objects haw been computed and the results have been compared with that for the aberration-free case. All the results are illustrated in graphical form.

Proceedings ArticleDOI
09 Jul 1992
TL;DR: In this paper, the authors used fifth order raytracing to determine the off-axis chromatic and spherical aberrations of a two-lens system and then calculated these as a function of the interlens spacing and were shown to have distinct minima.
Abstract: High performance focused ion beam systems utilizing liquid metal ion sources are performance limited due to the chromatic aberration of the optical elements and the finite energy spread of the ion source. Some concepts are presented to reduce the chromatic and spherical aberrations utilizing axially symmetric electrostatic optical elements. Unlike paraxial optics, in off-axis optics the individual aberrations of each lens element interact. This allows the total system aberrations to be minimized by optimizing lens parameters. Fifth order raytracing is used to determine the off-axis aberrations of a two lens system. The aberrations are then calculated as a function of the inter-lens spacing and are shown to have distinct minima. By optimizing the lens acceptance angle and the lens spacing off-axis chromatic aberration and the geometric aberrations (including spherical aberration) may be reduced to values below that achievable using paraxial optics at the same beam current. Novel coaxial optical lens designs are presented which also offers the possibility of chromatic aberration correction and may provide improved performance over conventional optics for special applications.

Journal ArticleDOI
TL;DR: In this paper, the performance of an off-axis holographic lens afflicted with third-order spherical aberration and coma using a numerical ray-tracing procedure was evaluated for both an extended coherent and an incoherent edge as well as bar objects.
Abstract: The aim of this paper is to evaluate the performance of an off-axis holographic lens afflicted with third-order spherical aberration and coma using a numerical ray-tracing procedure. The light intensity distribution in the aberration spot observed at the Gaussian image plane has been evaluated for different amounts of coma and for a fixed value of spherical aberration. The images of both an extended coherent and an incoherent edge as well as bar objects have been computed and the results compared with the aberration-free case. All the results are illustrated in graphical form.