Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
  • H03M3/00—Conversion of analogue values to or from differential modulation
  • H03M3/30—Delta-sigma modulation
  • H03M3/38—Calibration
  • H03M3/386—Calibration over the full range of the converter, e.g. for correcting differential non-linearity
  • H03M3/388—Calibration over the full range of the converter, e.g. for correcting differential non-linearity by storing corrected or correction values in one or more digital look-up tables
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B13/00—Optical objectives specially designed for the purposes specified below
  • G02B13/0095—Relay lenses or rod lenses
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
  • G02B17/08—Catadioptric systems
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
  • G02B17/08—Catadioptric systems
  • G02B17/0804—Catadioptric systems using two curved mirrors
  • G02B17/0808—Catadioptric systems using two curved mirrors on-axis systems with at least one of the mirrors having a central aperture
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
  • G02B17/08—Catadioptric systems
  • G02B17/0804—Catadioptric systems using two curved mirrors
  • G02B17/0812—Catadioptric systems using two curved mirrors off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
  • G02B17/08—Catadioptric systems
  • G02B17/0852—Catadioptric systems having a field corrector only
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
  • G02B17/08—Catadioptric systems
  • G02B17/0856—Catadioptric systems comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors
  • G02B17/086—Catadioptric systems comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors wherein the system is made of a single block of optical material, e.g. solid catadioptric systems
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
  • H03M3/00—Conversion of analogue values to or from differential modulation
  • H03M3/30—Delta-sigma modulation
  • H03M3/39—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators
  • H03M3/412—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the number of quantisers and their type and resolution
  • H03M3/422—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the number of quantisers and their type and resolution having one quantiser only
  • H03M3/424—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the number of quantisers and their type and resolution having one quantiser only the quantiser being a multiple bit one

Definitions

• the present invention relates to an aberration correcting optical relay for an optical system.
• the invention relates more particularly, but not exclusively, to mirror telescopes.
• the present invention aims to correct the geometric and / or chromatic aberrations of an optical system in a simpler and more economical way.
• the optical system is arranged as a telescope comprising a primary mirror and a secondary mirror
• the invention also makes it possible to substantially reduce the diameter of the secondary mirror.
• the invention also makes it possible to transfer the image from the optical system from a place that is difficult to access or inaccessible to a place accessible to observation.
• an optical aberration-correcting relay comprising two converging optical units, front and rear, and a correcting meniscus or two correcting menisci placed symmetrically with respect to each other, the meniscus being meniscus having substantially main faces.
• the two converging optical units being placed on the same axis and the correcting meniscus or meniscus on this axis and between the two converging optical units, the front converging optical unit located upstream of the correcting meniscus being arranged so that the distance between an image point of the part of the optical system upstream of the optical relay, on the one hand, and the converging optical unit before, on the other hand, is equal to the focal length of the block forward converging optic, the latter thus transforming a beam from said image point into a parallel beam
• the above-mentioned parallel beam strikes the meniscus parallel to the axis
• the above-mentioned parallel beam strikes the meniscus in an inclined manner relative to the axis
• the meniscus (s) are preferably with exactly concentric main faces
• two correcting menisci placed symmetrically with respect to each other is meant two menisci placed so that their centers of curvature coincide
• the meniscus may also be of small diameter and easy to produce, and thus allow advantageous production costs of the optical relay.
• the correction of aberrations can be carried out only at the level of the optical aberration corrector relay.
• the invention thus eliminates the use of complex shaped mirrors and full aperture correcting elements in the optical system.
• the beam becomes slightly divergent and meets the rear convergent optical unit, which is arranged to form an image at a location accessible to observation
• the optical elements constituting the optical relay are all with spherical faces
• the converging optical units can each include one or more lenses
• the correcting meniscus can be placed upstream or, preferably, downstream of the geometric center of the optical relay, geometric center on which all the parallel beams coming from the front optical unit converge
• the center of curvature of the meniscus may initially coincide, before subsequent adjustments, with this geometric center of the optical relay.
• aberration corrections can be made out of axis because the aforementioned inclined parallel beams are no longer centered on the meniscus, the parallel axial beam not affected.
• a divergent lens can be placed in front of the rear convergent optical unit, making it possible to improve various corrections, in the axis and off axis.
• At least one of the optical elements of the relay is formed by a doublet of two glasses having substantially the same index of refraction and strongly different Abbe numbers.
• a modification of the curvature of the internal face of the doublet makes it possible to correct to a large extent the chromatism without affecting the convergence of the doublet, therefore of the previous geometric adjustments.
• the optical system is arranged in a mirror telescope comprising a primary mirror and a secondary mirror and comprising an aberration correcting optical relay as defined above.
• the optical relay is advantageously placed downstream of the assembly constituted by the primary and secondary mirrors so that an image point originating from this assembly coincides with an object point of the optical relay.
• the optical relay can comprise two lenses forming the front converging optical unit, a lens forming the meniscus, a diverging lens and two lenses forming the rear converging optical unit, for a total of six lenses.
• the mirror telescope according to the invention can, in particular, be arranged as a NEWTON type telescope comprising a primary mirror of spherical shape and a secondary plane mirror, that is to say mirrors of simple shapes, easy to manufacture, while making it possible to obtain good quality images thanks to the optical relay.
• the diameter of the secondary mirror is much smaller than the diameter of the primary mirror.
• the diameter of the secondary mirror is of the order of 10% to 13% of the diameter of the primary mirror. It will be recalled that the diameter of the secondary mirror is of the order of 25% of the diameter of the primary mirror in the case of a conventional NEWTON type telescope.
• the secondary mirror being placed in the path of the incident beam on the primary mirror, it is advantageous to have a secondary mirror as small as possible, in order to collect a greater quantity of light and to minimize the diffraction effect induced by the edges of the secondary mirror.
• the present invention thus eliminates, at least partially, these drawbacks by using a secondary mirror of diameter much smaller than the diameter of the primary mirror.
• a reduction in the diameter of the secondary mirror is possible thanks to the use of the optical relay which makes it possible to transfer the image coming from the secondary mirror, and which can therefore form near it, in a place more easily accessible to observation.
• the length of the central tube of the telescope can be reduced.
• the optical relay preferably comprises a meniscus formed by a doublet of glasses such as that described above and a diverging lens formed by a simple glass arranged in front of the rear convergent optical unit.
• the mirror telescope according to the invention is arranged as a CASSEGRAIN type telescope and comprises a primary mirror of spherical shape and a secondary mirror also of spherical shape.
• the secondary mirror is much smaller than the diameter of the primary mirror.
• the diameter of the secondary mirror is of the order of 20% to 25% of the diameter of the primary mirror.
• the diameter of the secondary mirror is of the order of 35% to 45% of the diameter of the primary mirror in the case of a conventional CASSEGRAIN type telescope.
• Such a reduction in the diameter of the secondary mirror is possible thanks to the use of the optical relay which allows the image formed by the latter to be brought closer to the secondary mirror.
• the other advantages mentioned above for the NEWTON type telescope are also observed in the case of the CASSEGRAIN type telescope.
• the optical relay preferably comprises a meniscus formed by a single lens and a divergent lens formed by a doublet of two lenses having the same refractive index and significantly different Abbe numbers.
• the secondary mirror of the CASSEGRAIN type telescope according to the invention is advantageously a MANGIN type mirror, that is to say that the reflection takes place on the rear face of a divergent lens constituting the MANGIN mirror. We then obtain a quasi-perfect correction of the aberration of sphericity.
• the mirror telescope according to the invention is arranged as a NEWTON type telescope comprising a primary mirror of spherical shape oriented so as to direct the converging light beam towards a point located near the inner side wall of the telescope where the secondary mirror is placed.
• the secondary mirror constitutes only a minimal obstruction for the beam incident on the primary mirror.
• the secondary mirror is advantageously fixed to the inner side wall of the telescope by a single fixing means.
• the optical relay can be arranged inclined relative to the side wall of the telescope. The size of the telescope can thus be reduced.
• the primary mirror of spherical shape is oriented so as to direct the converging light beam towards a point located near the inner side wall of the telescope where the mirror is placed secondary.
• the secondary mirror constitutes only a minimal obstruction for the beam incident on the primary mirror.
• the secondary mirror is fixed to the inner side wall of the telescope by a single fixing means, thus eliminating the diffraction effect induced by the fixing of the secondary mirror.
• the invention thus makes it possible to produce an optical system arranged in a binocular telescope by associating two telescopes of the CASSEGRAIN type according to the particular embodiment which has just been described, each comprising an eyepiece and arranged parallel to one another, the eyepieces being spaced from each other by a distance corresponding to the spacing of a user's eyes.
• FIG. 1 is a view very schematic of an optical aberration correcting relay according to the invention
• FIGS. 2 and 3 schematically represent the optical elements constituting the optical relay of FIG. 1 according to first embodiments of the invention
• FIG. 4 is a schematic view, in axial section, of a NEWTON type telescope equipped with an aberration correcting optical relay according to the invention
• FIG. 5 is a schematic view, in axial section, of a CASSEGRAIN type telescope equipped with an optical aberration correcting relay according to the invention
• FIG. 1 is a view very schematic of an optical aberration correcting relay according to the invention
• FIGS. 2 and 3 schematically represent the optical elements constituting the optical relay of FIG. 1 according to first embodiments of the invention
• FIG. 4 is a schematic view, in axial section, of a NEWTON type telescope equipped with an aberration correcting optical relay according to the invention
• FIG. 5 is a schematic view, in axial section, of a CASSEGRAIN type telescope equipped with an optical aberration correcting relay according to
• FIG. 6 is a schematic view, in axial section, of a NEWTON type telescope equipped with an optical aberration correcting relay according to a vari ante for carrying out the invention
• - Figure 7 is a schematic view, in axial section, of a CASSEGRAIN type telescope equipped with an aberration correcting optical relay according to an alternative embodiment of the invention.
• FIG. 1 An aberration correcting optical relay 1 according to the invention, intended to equip an optical system, not shown.
• the direction of the light path is indicated by the arrow L.
• the optical relay 1 includes a converging front optical unit 2, a block rear convergent optic 3 and a corrector meniscus with concentric main faces 4 placed on the axis of symmetry S of the optical relay 1.
• the converging front optical unit 2 is arranged within the optical system so that the distance between an image point I or I ', in the plane P, formed by the part of the optical system upstream from the optical relay 1, on the one hand , and the optical unit converge before 2, on the other hand, is equal to the focal length of this front unit 2.
• the geometric center of the optical relay 1 in which all the parallel beams converge is designated in the drawing by the point O.
• the correcting meniscus 4 is placed downstream of the geometric center O and is positioned initially so that the center of curvature of the meniscus coincides with the center O.
• the optical relay 1 makes it possible to transfer the image formed in the plane P difficult to access to observation in an observation plane P 'situated in a place easily accessible to observation and where an eyepiece is placed for the observation of the image.
• the eyepiece can be replaced by a photographic plate or a CCD type device.
• a divergent lens 5 can be placed in front of the rear convergent optical unit 3, the role of which is explained below.
• This divergent lens 5 is constituted by a doublet of glasses 5 a and 5 b having identical refractive indices and strongly different Abbe numbers.
• the meniscus 4 is a simple glass.
• the divergent lens 5 is constituted by a simple lens and the correcting meniscus 4 by a doublet of lenses 4a and 4b having identical refractive indices and strongly different Abbe numbers.
• At least one of the optical elements constituting the optical relay 1 is constituted by such a doublet.
• the first step consists of the monochromatic correction in the axis. It is, in monochromatic light, from an image point I on the axis, formed by the part of the optical system upstream of the optical relay 1, to size the correcting meniscus 4 by acting on its radius of curvature and its thickness in order to obtain the best correction of the spherical aberration.
• This adjustment is made for example for a monochromatic light of median wavelength in the range of wavelengths selected.
• the second step consists of monochromatic off-axis correction, in particular with regard to coma and astigmatism.
• the third step is the color correction.
• step 3) therefore does not affect the results acquired during steps 1) and 2).
• step 2 ' consisting in choosing the best distance between the diverging lens 5 and the rear unit 3 and acting on the characteristics of the diverging lens 5 so as to optimize the settings outside. axis in particular.
• step 2 ' affects the results obtained in steps 1) and 2).
• FIG. 7 represents a NEWTON type telescope equipped with an optical aberration correcting relay 1.
• the telescope consists of a main cylinder 15 open at one end so as to form the pupil 16 of the telescope.
• a spherical mirror 17 forming the primary mirror of the telescope is placed at the other end of the cylinder 15.
• a plane mirror 22 forming the secondary mirror of the telescope is disposed inclined on the axis of symmetry X of the cylinder 15 so as to send the beams coming from the primary mirror 17 to the aberration correcting optical relay 1, which is mounted in a cylinder secondary 18 perpendicular to the main cylinder 15 and in which is housed the eyepiece, not shown, of the telescope.
• the image given by the telescope is formed in the observation plane P 'where - is placed the eyepiece for the observation of this one.
• the eyepiece can be replaced by a photographic plate or a CDD type device.
• the converging blocks front 2 and rear 3 each consist of a pair of lenses and the meniscus 4 is formed by a doublet as described above.
• FIG. 8 represents a CASSEGRAIN type telescope equipped with an optical aberration correcting relay 1.
• the primary mirror 17 'of the telescope consists of a spherical mirror in the center of which an opening 20 is made. This opening 20 accommodates a cylinder 21 of reduced diameter in which is disposed the optical relay 1 and an eyepiece, not shown.
• the secondary mirror is constituted by a spherical mirror 22 'placed on the Y axis of the telescope.
• An incident beam centered on the Y axis converges substantially towards a point F ', image point of the assembly formed for the primary 17' and secondary 22 'mirrors, located in front of the optical relay 1, which transfers the image from the point F 'at point F "accessible to observation.
• An additional converging lens can be placed in the vicinity of F ′ to further reduce the incident beam towards the cylinder 21 so as to further reduce its diameter.
• the secondary mirror 22 ′ is a MANGIN type mirror making it possible to substantially improve the correction of the aberration of sphericity.
• the front 2 and rear 3 optical units consist of two lenses and the meniscus 4 consists of a single lens.
• a divergent lens 5 constituted by a doublet as described above, is arranged behind the meniscus 4, in front of the rear block 3.
• FIG. 9 represents a NEWTON type telescope, the plane secondary mirror 22 "of which is placed near the inner side wall 19" of the cylinder 15 "of the telescope.
• the primary spherical mirror 17" of the telescope is oriented so as to direct the beam bright incident towards the secondary mirror 22 ".
• the 17 "mirror is a portion of a large virtual spherical mirror centered on the optical relay 1.
• the secondary mirror 22 is fixed to the inner side wall 19" of the telescope by a single fixing means 23.
• the secondary mirror 22 By its offset position, near the inner side wall 19 ", the secondary mirror 22" constitutes only a reduced obstruction for the beam incident on the 17 "primary mirror.
• the cylinder 24 housing the optical relay 1 and the eyepiece is inclined in the example described by an angle ⁇ of 15 ° relative to the cylinder 15 "of the telescope.
• FIG. 10 represents a CASSEGRAIN type telescope comprising a primary mirror of spherical shape 17 '"oriented so as to direct the converging light beam towards a point located near the inner side wall 19" of the cylinder 15 "of the telescope where the secondary mirror 22 '"is placed.
• the mirror 17 '" is a portion of a large virtual spherical mirror centered on the optical relay 1.
• the secondary mirror 22'" is fixed to the inner side wall 19 '"by a single fixing means (not shown).
• the cylinder 25 in which the optical aberration corrector relay 1 is mounted and an eyepiece is placed against the inner side wall 19 ′′ of the telescope.
• the association of two telescopes of the type illustrated in FIG. 10 allows the production of a binocular telescope, the two telescopes being for this purpose arranged parallel to each other, the cylinders 25 respectively being arranged being spaced from each other d 'a distance corresponding to the spacing of a user's eyes (60 to 65 mm). This association is in particular possible because the optical relay 1 straightens the images.
• the aberration correcting optical relay can in particular be used in other optical systems, such as a periscope, a laser optical system, or a projection system for example.
• the aberration correcting optical relay can obviously be used for any optical system involving one or more optical relays.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Nonlinear Science (AREA)
• Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• Lenses (AREA)
• Telescopes (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=8847811

Family Applications (1)

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Family Cites Families (18)

• 2000
  • 2000-03-07 FR FR0002911A patent/FR2806170B1/fr not_active Expired - Fee Related
• 2001
  • 2001-03-07 EP EP01913953A patent/EP1261891A2/de not_active Withdrawn
  • 2001-03-07 US US10/220,406 patent/US6735014B2/en not_active Expired - Fee Related
  • 2001-03-07 AU AU39355/01A patent/AU3935501A/en not_active Abandoned
  • 2001-03-07 CA CA002401328A patent/CA2401328A1/fr not_active Abandoned
  • 2001-03-07 WO PCT/FR2001/000683 patent/WO2001067153A2/fr active Application Filing

Non-Patent Citations (1)

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