Designs for mitigating retroreflections in night vision systems are described. The designs described herein use diffraction gratings. A diffraction grating diffracts input light into several beams with different directions. A grating may be configured to transmit input light passing through an aperture stop towards the focal plane array (FPA), and to deviate reflections arising from the FPA in response to the input light outside aperture stop. Deviation of light may be obtained by designing the grating so that the majority of the total diffracted energy is concentrated in a single diffraction order while the energy in the other orders is limited. The diffraction order in which the energy is concentrated may be any diffraction order other than the zeroth order (the un-diffracted order), including for example the first order, the second order, the third order, etc. A grating may be formed as a discrete component or monolithically with the FPA.
G02B 23/12 - Télescopes ou lunettes d'approche, p.ex. jumelles; Périscopes; Instruments pour voir à l'intérieur de corps creux; Viseurs; Pointage optique ou appareils de visée avec des moyens pour renverser ou intensifier l'image
G02B 27/00 - Systèmes ou appareils optiques non prévus dans aucun des groupes ,
G02B 27/46 - Systèmes utilisant des filtres spatiaux
Described herein are passive systems and methods for ranging objects. The systems and methods are passive in that they do not rely on transmission of radiation (whether radiofrequency, visible, infrared, ultraviolet, acoustic, etc.) to determine range. The systems and methods described herein may be used both in civilian and military applications. The present techniques allow users to determine range to moving targets, which is notoriously difficult to estimate using the human eye. The present techniques perform ranging to a target using artificial intelligence models, including object segmentation and pose estimation. Object segmentation may involve determining a dimension (e.g., height) of a specified target in an image, in terms of pixels. If there are multiple objects in the scene, range estimates may be calculated using object segmentation for each object. Pose estimation involves a machine learning technique that identifies sets of coordinates corresponding to joint keypoints.
An optical projection assembly directs a first image to an eyebox of a user combined with light from a second source. A relay optic has a non-rotationally symmetric refractive gradient-index (GRIN) component arranged to receive the first image. A tilted, partially reflective combiner has a tilted first surface to receive and transmit the light from the second source, and an opposite second surface to receive and project the first image from the relay optic and transmit the light received from the second source to the eyebox. The GRIN component is configured to reduce a perceivable aberration of the first image introduced by the combiner.
An optical system providing reduced retroreflection includes an optical element with an optic aperture. A retroreflection defeat filter has a partially obstructing material configured to absorb or reflect a subset of the optical system waveband while transmitting the rest. The partially obstructing material is arranged to occupy a first portion of the optic aperture being at least half of the optic aperture, and the partially obstructing material does not occupy a second portion of the optic aperture for the remainder of the optic aperture.
A method for forming a weapon accessory mounting device to attach to a projectile firing weapon is disclosed. A flexure for receiving a body of the weapon accessory is formed. A pivot portion is formed at a first end of the flexure to attach the flexure to the weapon at a first attachment region. A second attachment portion is formed at a second end of the flexure to attach the flexure to the weapon at a second attachment region. A first aperture is formed in the pivot portion configured to receive a pivot pin. A second aperture in the weapon accessory body receives the pivot pin at a weapon accessory body first end to attach the weapon accessory body first end to the pivot portion. The pivot portion is configured to convert at least a portion of energy of a weapon shock recoil from translational energy to rotational energy.
Described herein are passive systems and methods for ranging objects. The systems and methods are passive in that they do not rely on transmission of radiation (whether radiofrequency, visible, infrared, ultraviolet, acoustic, etc.) to determine range. The systems and methods described herein may be used both in civilian and military applications. The present techniques allow users to determine range to moving targets, which is notoriously difficult to estimate using the human eye. The present techniques perform ranging to a target using artificial intelligence models, including object segmentation and pose estimation. Object segmentation may involve determining a dimension (e.g., height) of a specified target in an image, in terms of pixels. If there are multiple objects in the scene, range estimates may be calculated using object segmentation for each object. Pose estimation involves a machine learning technique that identifies sets of coordinates corresponding to joint keypoints.
An optical projection assembly directs a first image to an eyebox of a user combined with light from a second source. A relay optic has a non-rotationally symmetric refractive gradient- index (GRIN) component arranged to receive the first image. A tilted, partially reflective combiner has a tilted first surface to receive and transmit the light from the second source, and an opposite second surface to receive and project the first image from the relay optic and transmit the light received from the second source to the eyebox. The GRIN component is configured to reduce a perceivable aberration of the first image introduced by the combiner.
An optical projection assembly directs a first image to an eyebox of a user combined with light from a second source. A relay optic has a non-rotationally symmetric refractive gradient- index (GRIN) component arranged to receive the first image. A tilted, partially reflective combiner has a tilted first surface to receive and transmit the light from the second source, and an opposite second surface to receive and project the first image from the relay optic and transmit the light received from the second source to the eyebox. The GRIN component is configured to reduce a perceivable aberration of the first image introduced by the combiner.
An optical system providing reduced retroreflection includes an optical element with an optic aperture. A retroreflection defeat filter has a partially obstructing material configured to absorb or reflect a subset of the optical system waveband while transmitting the rest. The partially obstructing material is arranged to occupy a first portion of the optic aperture being at least half of the optic aperture, and the partially obstructing material does not occupy a second portion of the optic aperture for the remainder of the optic aperture.
G02B 23/12 - Télescopes ou lunettes d'approche, p.ex. jumelles; Périscopes; Instruments pour voir à l'intérieur de corps creux; Viseurs; Pointage optique ou appareils de visée avec des moyens pour renverser ou intensifier l'image
An optical system providing reduced retroreflection includes an optical element with an optic aperture. A retroreflection defeat filter has a partially obstructing material configured to absorb or reflect a subset of the optical system waveband while transmitting the rest. The partially obstructing material is arranged to occupy a first portion of the optic aperture being at least half of the optic aperture, and the partially obstructing material does not occupy a second portion of the optic aperture for the remainder of the optic aperture.
G02B 23/12 - Télescopes ou lunettes d'approche, p.ex. jumelles; Périscopes; Instruments pour voir à l'intérieur de corps creux; Viseurs; Pointage optique ou appareils de visée avec des moyens pour renverser ou intensifier l'image
11.
Method for shock attenuation device using a pivot mechanism
A method for forming a weapon accessory mounting device to attach to a projectile firing weapon is disclosed. A flexure for receiving a body of the weapon accessory is formed. A pivot portion is formed at a first end of the flexure to attach the flexure to the weapon at a first attachment region. A second attachment portion is formed at a second end of the flexure to attach the flexure to the weapon at a second attachment region. A first aperture is formed in the pivot portion configured to receive a pivot pin. A second aperture in the weapon accessory body receives the pivot pin at a weapon accessory body first end to attach the weapon accessory body first end to the pivot portion. The pivot portion is configured to convert at least a portion of energy of a weapon shock recoil from translational energy to rotational energy.
An optical system for overlaying a first image of a scene and a second image includes an image intensified night vision and/or telescopic device providing the first image, a second imaging device with an image display and collimation optics providing the second image, and a waveguide. The waveguide has a first diffraction grating configured to receive the first image, a second diffraction grating configured to receive the second image, and a guide portion disposed between the first diffraction grating and the second diffraction grating configured to convey the second image to the first grating. The first diffraction grating is configured to overlay the first image and the second image.
An optical element (200), has a first surface configured to convey light, a second surface configured to convey light, an optical path between the first surface and the second surface, a filter coating (230) applied to the first surface, and a colour corrected anti-reflection (AR) coating (240) with colour correcting and antireflection characteristics applied to the second surface. The AR coating is configured according to an antireflective function to maximise photopic transmission and/or, integrated visual photopic transmission (IVPT) of the optical path. The second surface is disposed opposite the first surface, and the antireflective function is determined according to a daylight emission a I(λ), a transmission spectrum of the antireflection/colour corrective coating T(λ) and a thickness a d(λ), of the film for a specified wavelength.
C23C 14/06 - Revêtement par évaporation sous vide, pulvérisation cathodique ou implantation d'ions du matériau composant le revêtement caractérisé par le matériau de revêtement
C03C 17/34 - Traitement de surface du verre, p.ex. du verre dévitrifié, autre que sous forme de fibres ou de filaments, par revêtement avec au moins deux revêtements ayant des compositions différentes
A method for forming a weapon accessory mounting device to attach to a projectile firing weapon is disclosed. A flexure for receiving a body of the weapon accessory is formed. A pivot portion is formed at a first end of the flexure to attach the flexure to the weapon at a first attachment region. A second attachment portion is formed at a second end of the flexure to attach the flexure to the weapon at a second attachment region. A first aperture is formed in the pivot portion configured to receive a pivot pin. A second aperture in the weapon accessory body receives the pivot pin at a weapon accessory body first end to attach the weapon accessory body first end to the pivot portion. The pivot portion is configured to convert at least a portion of energy of a weapon shock recoil from translational energy to rotational energy.
An optical system for overlaying a first image of a scene and a second image includes a first imaging device providing the first image, a second imaging device with an image display and collimation optics providing the second image, and a waveguide. The waveguide has a first diffraction grating configured to receive the first image, a second diffraction grating configured to receive the second image, and a guide portion disposed between the first diffraction grating and the second diffraction grating configured to convey the second image to the first grating. The first diffraction grating is configured to overlay the first image and the second image.
A system and method for a weapon accessory mount is disclosed. The weapon accessory mount is configured to attach a weapon accessory to a rail of a weapon configured to fire a projectile in a projectile path. A flexure is configured to receive the weapon accessory. The flexure includes a first end attached to the rail at a first pivot portion, and a second end opposite the first end attached to the rail at a second portion. The first pivot portion is configured to convert at least a portion of energy of a shock recoil from the weapon from translational energy to rotational energy, the second pivot portion has a similar functionality to the first pivot portion.
A blended optical device includes a first objective with a first axis and a first image position adjustment means for adjusting the position of a first image. An electronic control circuitry is configured to control the first adjustment means to adjust a position of the first image. A second objective includes a second axis and a variable focus mechanism, and a blender configured to form a blended image from the first image and a second image. The electronic control circuitry is configured to receive data from the second objective regarding a range to a target of the second objective as a function of the focus setting, and to adjust the position of the first image so that the blended image is corrected for parallax errors.
G02B 7/02 - Montures, moyens de réglage ou raccords étanches à la lumière pour éléments optiques pour lentilles
G02B 7/08 - Montures, moyens de réglage ou raccords étanches à la lumière pour éléments optiques pour lentilles avec mécanisme de mise au point ou pour faire varier le grossissement adaptés pour fonctionner en combinaison avec un mécanisme de télécommande
H04N 13/128 - Ajustement de la profondeur ou de la disparité
H04N 13/167 - Synchronisation ou commande des signaux d’images
H04N 13/225 - Générateurs de signaux d’images utilisant des caméras à images stéréoscopiques utilisant un seul capteur d’images 2D utilisant des barrières de parallaxe
H04N 13/236 - Générateurs de signaux d’images utilisant des caméras à images stéréoscopiques utilisant un seul capteur d’images 2D utilisant des lentilles à foyer progressif ou des miroirs
G02B 23/12 - Télescopes ou lunettes d'approche, p.ex. jumelles; Périscopes; Instruments pour voir à l'intérieur de corps creux; Viseurs; Pointage optique ou appareils de visée avec des moyens pour renverser ou intensifier l'image
G06T 7/33 - Détermination des paramètres de transformation pour l'alignement des images, c. à d. recalage des images utilisant des procédés basés sur les caractéristiques
A system includes an optical waveguide configured to receive multispectral radiation from a scene, a first optical component and a second optical component. The first optical component is configured to cause a first portion of the multispectral radiation with wavelengths in a first range to exit the optical waveguide at a first position, and a second portion of the multispectral radiation with wavelengths in a second range to travel through the optical waveguide from the first position to a second position via total internal reflection. The second optical component is configured to cause the second portion of the multispectral radiation to exit the optical waveguide at the second position.
G02B 17/00 - Systèmes avec surfaces réfléchissantes, avec ou sans éléments de réfraction
G02B 23/04 - Télescopes ou lunettes d'approche, p.ex. jumelles; Périscopes; Instruments pour voir à l'intérieur de corps creux; Viseurs; Pointage optique ou appareils de visée comprenant des prismes ou des miroirs afin de partager ou de combiner des faisceaux lumineux, p.ex. munis d'oculaires pour plus d'un observateur
H04N 5/33 - Transformation des rayonnements infrarouges
A head-up display includes a projector and an optical combiner configured to reflect light from the projector while allowing other wavelengths of light to pass through the optical combiner. The projector has two or more image sources, and two or more optical components, each of which is associated with a corresponding one of the image sources. In a typical implementation, the two or more optical components are closely situated to approximate an effective aperture that is larger than the actual aperture of either optical component. In such an implementation, since the actual aperture of each respective optical element is smaller than the larger effective aperture, it is generally much easier to correct for optical aberrations and the like, than it would be if a single optical element with a larger actual aperture were used.
A system includes a dome-shaped optical component having a substantially circular edge and a mounting base for the optical component. A recess is in an outer surface of the optical component. A projection on an inner surface of the mounting base and is configured to engage the recess. An adhesive material is between the optical component and the mounting base. The adhesive material forms an upper band and a lower band with a void between the upper band and the lower band. The void is positioned relative to the recess in the outer surface of the optical component such that a bending stress in the optical component at the recess is less than what the bending stress would be without the void. A heater is inside and thermally coupled to the optical component.
G02B 7/00 - Montures, moyens de réglage ou raccords étanches à la lumière pour éléments optiques
G02B 7/02 - Montures, moyens de réglage ou raccords étanches à la lumière pour éléments optiques pour lentilles
F16B 11/00 - Assemblage d'éléments structuraux ou parties de machines par collage ou en les pressant l'un contre l'autre, p.ex. soudage sous pression à froid
F16B 47/00 - Ventouses pour accrochage; Moyens équivalents utilisant des adhésifs
A47G 29/00 - Supports, appuis ou récipients divers à usage domestique, non prévus dans les groupes ou
G11B 7/135 - Moyens pour guider le faisceau de la source au support d'enregistrement, ou du support d'enregistrement au détecteur
G11B 7/22 - Appareils ou procédés pour la fabrication des têtes optiques, p.ex. pour l’assemblage
21.
Parallax correction device and method in blended optical system for use over a range of temperatures
A blended optical device includes a first objective with a first axis and a first image position adjustment means for adjusting the position of a first image. An electronic control circuitry is configured to control the first adjustment means to adjust a position of the first image. A second objective includes a second axis and a variable focus mechanism, and a blender configured to form a blended image from the first image and a second image. The electronic control circuitry is configured to receive data from the second objective regarding a range to a target of the second objective as a function of the focus setting, and to adjust the position of the first image so that the blended image is corrected for parallax errors.
G06T 7/33 - Détermination des paramètres de transformation pour l'alignement des images, c. à d. recalage des images utilisant des procédés basés sur les caractéristiques
G02B 7/08 - Montures, moyens de réglage ou raccords étanches à la lumière pour éléments optiques pour lentilles avec mécanisme de mise au point ou pour faire varier le grossissement adaptés pour fonctionner en combinaison avec un mécanisme de télécommande
G02B 7/02 - Montures, moyens de réglage ou raccords étanches à la lumière pour éléments optiques pour lentilles
G02B 23/12 - Télescopes ou lunettes d'approche, p.ex. jumelles; Périscopes; Instruments pour voir à l'intérieur de corps creux; Viseurs; Pointage optique ou appareils de visée avec des moyens pour renverser ou intensifier l'image
H04N 13/128 - Ajustement de la profondeur ou de la disparité
H04N 13/167 - Synchronisation ou commande des signaux d’images
H04N 13/225 - Générateurs de signaux d’images utilisant des caméras à images stéréoscopiques utilisant un seul capteur d’images 2D utilisant des barrières de parallaxe
H04N 13/236 - Générateurs de signaux d’images utilisant des caméras à images stéréoscopiques utilisant un seul capteur d’images 2D utilisant des lentilles à foyer progressif ou des miroirs
A system includes an optical waveguide configured to receive multispectral radiation from a scene, a first optical component and a second optical component. The first optical component is configured to cause a first portion of the multispectral radiation with wavelengths in a first range to exit the optical waveguide at a first position, and a second portion of the multispectral radiation with wavelengths in a second range to travel through the optical waveguide from the first position to a second position via total internal reflection. The second optical component is configured to cause the second portion of the multispectral radiation to exit the optical waveguide at the second position.
F21V 8/00 - Utilisation de guides de lumière, p.ex. dispositifs à fibres optiques, dans les dispositifs ou systèmes d'éclairage
G02B 27/10 - Systèmes divisant ou combinant des faisceaux
G02B 17/00 - Systèmes avec surfaces réfléchissantes, avec ou sans éléments de réfraction
G02B 23/04 - Télescopes ou lunettes d'approche, p.ex. jumelles; Périscopes; Instruments pour voir à l'intérieur de corps creux; Viseurs; Pointage optique ou appareils de visée comprenant des prismes ou des miroirs afin de partager ou de combiner des faisceaux lumineux, p.ex. munis d'oculaires pour plus d'un observateur
A system includes a dome-shaped optical component having a substantially circular edge and a mounting base for the optical component. A recess is in an outer surface of the optical component. A projection on an inner surface of the mounting base and is configured to engage the recess. An adhesive material is between the optical component and the mounting base. The adhesive material forms an upper band and a lower band with a void between the upper band and the lower band. The void is positioned relative to the recess in the outer surface of the optical component such that a bending stress in the optical component at the recess is less than what the bending stress would be without the void. A heater is inside and thermally coupled to the optical component.
G02B 7/00 - Montures, moyens de réglage ou raccords étanches à la lumière pour éléments optiques
G02B 7/02 - Montures, moyens de réglage ou raccords étanches à la lumière pour éléments optiques pour lentilles
F16B 11/00 - Assemblage d'éléments structuraux ou parties de machines par collage ou en les pressant l'un contre l'autre, p.ex. soudage sous pression à froid
A field inverting optical waveguide is disclosed. The waveguide is configured to convey electromagnetic radiation from an ingress end to an egress end along an optical path. The waveguide includes an optically flat input surface disposed at the waveguide ingress end, and an exit surface disposed substantially opposite the input surface at the waveguide egress end. The exit surface includes an array of prisms projecting outward from or inward to the exit surface. The input surface and the exit surface are arranged substantially orthogonally to the optical path.
A field inverting optical waveguide is disclosed. The waveguide is configured to convey electromagnetic radiation from an ingress end to an egress end along an optical path. The waveguide includes an optically flat input surface disposed at the waveguide ingress end, and an exit surface disposed substantially opposite the input surface at the waveguide egress end. The exit surface includes an array of prisms projecting outward from or inward to the exit surface. The input surface and the exit surface are arranged substantially orthogonally to the optical path.
A method and device for a compact shock isolation apparatus are disclosed. The apparatus is adapted for mounting a sensitive component to a base. The apparatus includes a collar, a plurality of axial flexures mounted to the base to attenuate an axial shock force/acceleration. A plurality of radial flexures extend axially between the collar and the axial flexures, connecting each of the axial flexures to the collar to attenuate radial and/or circumferential shock forces/acceleration. A plurality of attachment pads disposed between adjacent radial flexures extend axially from the collar toward the axial flexures and attach to the sensitive component. The shock isolation apparatus supports the sensitive component in non-contacting proximity to the base. The apparatus optionally includes vibration dampening material disposed between the sensitive component and the axial flexures and/or the radial flexures.
F41G 1/38 - Appareils de visée télescopiques spécialement adaptés aux armes à feu individuelles ou aux pièces d'artillerie; Leurs supports ou leurs montures
F16F 1/14 - Ressorts de torsion faits de barres ou de tubes
F16F 15/06 - Suppression des vibrations dans les systèmes non rotatifs, p.ex. dans des systèmes alternatifs; Suppression des vibrations dans les systèmes rotatifs par l'utilisation d'organes ne se déplaçant pas avec le système rotatif utilisant des moyens élastiques avec ressorts métalliques
F16F 1/02 - Ressorts en acier ou faits d'un autre matériau ayant une faible friction intérieure; Ressorts enroulés, de torsion, à lame, en forme de coupelles, à corps annulaire ou similaire, le matériau de ressort ne jouant pas de rôle
27.
SHOCK ISOLATION PROTECTION OF SENSITIVE COMPONENTS
A method and device for a compact shock isolation apparatus are disclosed. The apparatus is adapted for mounting a sensitive component to a base. The apparatus includes a collar, a plurality of axial flexures mounted to the base to attenuate an axial shock force/acceleration. A plurality of radial flexures extend axially between the collar and the axial flexures, connecting each of the axial flexures to the collar to attenuate radial and/or circumferential shock forces/acceleration. A plurality of attachment pads disposed between adjacent radial flexures extend axially from the collar toward the axial flexures and attach to the sensitive component. The shock isolation apparatus supports the sensitive component in non- contacting proximity to the base. The apparatus optionally includes vibration dampening material disposed between the sensitive component and the axial flexures and/or the radial flexures.
09 - Appareils et instruments scientifiques et électriques
42 - Services scientifiques, technologiques et industriels, recherche et conception
Produits et services
Commercial off-the-shelf lenses for use on thermal weapon sights, fused sights, thermal goggles, and fused night vision goggles; commercial off-the-shelf lenses for use on situational awareness, border surveillance, and vehicle thermal night vision and targeting; commercial off-the-shelf lenses for use on remote weapon stations, drivers vision enhancement, test equipment, laboratory demonstration, surveillance cameras, and hand held surveillance sights; commercial off-the-shelf lenses for use on cameras for UAV payloads, thermography, machine vision, process control, metrology, and security; commercial off-the-shelf lenses for use on building diagnostics, remote temperature sensing, and thermal imaging. Scientific and technological services and research and design relating thereto; industrial analysis and research services.
29.
A MOUNT ARRANGEMENT FOR SUPPORTING A TAPERED LIGHT PIPE
There is disclosed mount arrangement for supporting a tapered light pipe (5) of a type having a relatively wide end (8), a relatively narrow end (7), and an outer surface (9). The mount arrangement includes: a support assembly (25) provided within a housing (13) and having a central bore (28) for receipt of a said light pipe (5) through the support assembly (25), the support assembly (25) being arranged for movement within the housing (13) along the axis of the bore (28), and having within said central bore (28) an array of inwardly directed convex bearing surfaces (33) arranged in spaced relation to one another around the central bore (28). The support assembly (25) is biased towards the relatively wide end (8) of the light pipe (5) so as to urge the convex bearing surfaces (33) into contact with the outer surface (9) of the light pipe (5).
There is disclosed a system and associated method for mounting an optical component in an optical arrangement. An optical component (1) is provided having a circular edge region (5). A mount (9) having a circular wall is also provided, the circular wall being configured for radially-spaced cooperation with the circular edge region of the optical component. The system is configured such that one of said circular edge region (5) and said circular wall (17) has a plurality of spaced-apart protrusions (23) provided around it. The other of the circular edge region (5) and the circular wall (17) has a plurality of spaced-apart recesses provided around it. The protrusions (23) and the recesses (7) are configured such that each protrusion (23) may be aligned with a respective recess (7) and engaged within said recess (7) via relative rotation between the optical component (1) and the mount (9). The system further includes an adhesive (32) for application between said circular edge region (5) and said circular wall (17) to adhesively fix the optical component (1) in position relative to the mount (9).
There is disclosed a radiation stable shield for use in space or high altitude applications. The shield comprises a plurality of overlapping planar glass flakes which are held in a lamellar matrix of flexible polymeric material. The flakes are each formed of a radiation stable glass which is suitable for use in space or high altitude applications. The flakes are arranged in alignment with the lamellar direction of the matrix.
A method of measuring the thickness distribution of a deposited layer of coating material, the method including: adapting the shape of a flexible test sheet so that the flexible test sheet has a curved test surface representative of a curved surface of a component; depositing vaporised coating material on the curved test surface of the flexible test sheet to form a layer of coating material on the curved test surface of the flexible test sheet; and measuring a parameter representative of the thickness of the deposited layer of coating material at two or more locations on the test surface of the flexible test sheet.
C23C 14/54 - Commande ou régulation du processus de revêtement
C23C 16/52 - Commande ou régulation du processus de dépôt
C23C 14/04 - Revêtement de parties déterminées de la surface, p.ex. au moyen de masques
G01B 21/08 - Dispositions pour la mesure ou leurs détails, où la technique de mesure n'est pas couverte par les autres groupes de la présente sous-classe, est non spécifiée ou est non significative pour mesurer la longueur, la largeur ou l'épaisseur pour mesurer l'épaisseur
33.
METHOD AND APPARATUS FOR COATING ON THE CONCAVE SURFACE OF A COMPONENT
A method of depositing a layer of coating material on a concave surface of a component, the method including the steps of vaporising coating material at a source of coating material to produce vaporised coating material and depositing the vaporised coating material on the concave surface to form a layer of coating material covering an area of the concave surface which extends from an apex of the concave surface up to at least a depth d from the apex of the concave surface. The source of coating material and the component are kept at a substantially fixed distance apart during the depositing of the vaporised coating material. The substantially fixed distance being determined such that a thickness of the deposited layer of coating material at the apex of the concave surface is substantially equal to a thickness of the deposited layer of coating material at the depth d from the apex of the concave surface.
An optical adaptor (19) is disclosed for use in combination with an optical imaging system (10). The adaptor is specifically configured so that when it is positioned within the optical path between an object (8) and the imaging system, the adaptor corrects the field curvature of the imaging system so as to produce a substantially flat image of a curved object. The adaptor comprises a primary lens unit (20) of positive power which in use is towards the object and which preferably takes the form of a thick meniscus lens having an overcorrect Petzval Sum, and a secondary lens unit (21) of negative power which in use is towards the imaging system and which preferably takes the form of a relatively thin meniscus lens.
