Abstract: An objective having an apical lens and a lens frame which supports the apical lens, includes an elastic member which supports the lens frame by exerting a bias force in a central axial direction of the apical lens, and an apex of the lens frame has a convex portion which projects outward in the central axial direction more than an apical surface of the apical lens.

Abstract: In a lithographic projection apparatus, a liquid supply system provides liquid in a space between the final element of the projection system and the substrate of the lithographic projection apparatus. A shutter member is provided to contain liquid in the liquid supply system during, for example, substrate exchange.

Abstract: A substrate is provided with a coating of material which is substantially transparent to the wavelength of the projection beam. The coating may be thicker than the wavelength of the projection beam and have a refractive index of the coating such that the wavelength of the projection beam is shortened as it passes through it. This allows the imaging of smaller features on the substrate. Alternatively, the coating may be used with a liquid supply system and act to keep bubbles away from a radiation sensitive layer of the substrate.

Abstract: A lithographic apparatus is disclosed. The apparatus includes a radiation system that provides a beam of radiation, and a support structure that supports a patterning structure. The patterning structure is configured to pattern the beam of radiation according to a desired pattern. The apparatus also includes a substrate support that supports a substrate, and a projection system that projects the patterned beam onto a target portion of the substrate. The projection system includes an optical element that has a beam entry area and an optical element that has a beam exit area through each of which the patterned beam passes. The apparatus further includes a nucleated surface that is associated with the projection system on which a plurality of nucleation sites are provided. The surface is disposed away from at least one of the beam entry area and the beam exit area.

Abstract: In a lithographic projection apparatus, a space between an optical element is filled with a first fluid and a second fluid separated by a transparent plate. The first and second fluids have different first and second indices of refraction, respectively. The first fluid is provided between a substrate and the transparent plate and has an index of refraction similar to the index of refraction of the substrate. The second fluid is provided between the transparent plate and the optical element and has an index of refraction similar to the index of refraction of the optical element. The transparent plate has a third index of refraction between the first and second indices of refraction and may be equal to the first index of refraction or the second index of refraction.

Abstract: An assembly according to an embodiment of the invention includes a sensor for determining at least one of tilt and height of a surface of a substrate in a lithographic apparatus. The substrate is moveable along at least one path substantially parallel to the surface of the substrate with respect to the sensor. The lithographic apparatus has an exposure scanning direction and the assembly is arranged to move the substrate relative to the sensor along the at least one path and to provide measurement data about the at least one of tilt and height along the at least one path. The assembly includes a memory configured to store the measurement data for use during a later exposure of the substrate by the lithographic apparatus. The at least one path of the substrate is at least partly at an angle to the exposure scanning direction.

Abstract: In an immersion lithography apparatus, a member surrounds a space between a projection system and a substrate table. A seal is formed to contain liquid in the space.

Abstract: Exposure systems are disclosed having a configuration in which a field stop is positioned in proximity to a reflection-type mask, but that satisfactorily minimize adverse effects on the image-forming performance of the projection-optical system. The systems transfer a mask pattern accurately and with high throughput onto a photosensitive substrate. The system comprises an illumination-optical system (1, 2) that illuminates a reflection-type mask (M) on which is formed a prescribed pattern. A projection-optical system forms an image of the mask pattern on the photosensitive substrate (W). The mask and substrate are moved in a prescribed direction relative to the projection-optical system to project the mask pattern onto and expose the photosensitive substrate. The illumination-optical system has a field stop (19), positioned in proximity to the mask, that defines the illumination area on the mask. The interval between the mask and the field stop satisfies a prescribed conditional relation.

Abstract: A writing device is provided which, in simple processes, can write in two dimensions and three dimensions, and which can form highly accurate patterns. An exposure head, a conductive material discharging head, and an insulating material discharging head are disposed at one scanning stage. At the one scanning stage, a pattern can be formed on a printed board which is on the scanning stage. As a result, processes can be simplified, time between patternings can be shortened, and pattern formation can be made to be faster. Moreover, positional offset of the exposure head and the discharging heads with respect to the printed board does not arise. Thus, it is easy to increase a density of a pattern, and a highly accurate pattern is formed.

Abstract: In a lithographic projection apparatus, a space between an optical element is filled with a first fluid and a second fluid separated by a transparent plate. The first and second fluids have first and second indices of refraction, respectively, that are different from one another. The first fluid is provided between a substrate and the transparent plate and has an index of refraction similar to the index of refraction of the substrate. The second fluid is provided between the transparent plate and the optical element and has an index of refraction similar to the index of refraction of the optical element. The transparent plate has a third index of refraction between the first and second indices of refraction and may be equal to the first index of refraction or the second index of refraction. A device manufacturing method includes filling a space between the optical element and the substrate with at least two fluids having different indices of refraction.

Abstract: There is provided an illumination apparatus including an optical integrator including multiple optical systems for receiving light from a light source, and for producing multiple beams for illuminating a plane of mask or reticle on which a pattern is draw, a position of an incidence plane of the optical integrator and a position of the plane to be illuminated being arranged optically conjugate with each other, and a device for forming an optical characteristic distribution of light at the incidence plane, the light entering at least part of the multiple optical systems, whereby different areas on the plane of plane to be illuminated can be illuminated under different illumination conditions.

Abstract: Apparatus, methods, and systems for immersion lithography. In one implementation, a hemispherical lens element is positioned near a target surface covered by photoresist. An immersion liquid is juxtaposed between the target surface and the lens element. A projected light is directed through the lens element and the immersion liquid to image a mask on the target surface.

Abstract: The present invention relates to a method of controlling the output of laser pulses where laser pulses are continuously emitted while performing charging for each pulse. This method comprises: a pre-charging step for commencing charging for a next pulse with a previously set first charging voltage value as a target; a voltage computation step for computing a second charging voltage value required for the next pulse during the pre-charging step; and a fine charging step for continuing charging for the next pulse with the second charging voltage value as the target instead of the first charging voltage value, when the second charging voltage value is computed in the voltage computation step.

Abstract: A method, exposure apparatus, and printed wafer such that a design is printed within a peripheral portion of the wafer. The peripheral portion of the wafer is between an outer boundary of an active portion of the wafer and an outer boundary of the wafer. The exposure apparatus comprises a lens, a reticle that includes a pattern, and a reticle blind. The reticle blind blocks a first portion of light that is passed through the exposure apparatus. A transparent portion of the reticle transmits a remaining portion of the light. The lens focuses the remaining portion of the light onto the wafer such that an image of a portion of the pattern is printed as the design within the peripheral portion of the wafer. The printed design is a function of where the reticle blind is positioned relative to the pattern.

Abstract: A system for regulating an exposure condition determining process is provided. The system includes one or more light sources, each light source directing light to one or more gratings exposed on one or more portions of a wafer. Light reflected from the gratings is collected by a measuring system, which processes the collected light. Light passing through the gratings may similarly be collected by the measuring system, which processes the collected light. The collected light is analyzed to determine whether exposure conditions should be adapted prior to exposing a pattern on the wafer. The measuring system provides grating signature data to a processor that determines the acceptability of the exposure condition by comparing determined signatures to desired signatures. The system also includes an exposing system that can be controlled to change exposure conditions. The processor selectively controls the exposing system, via the exposer driving system, to adapt such exposure conditions.

Abstract: The present invention is directed to a system and a method for calibrating a lithography stepper system. The system includes a lithography stepper system, measurement system such as a scatterometry system, and a processor for correlating an ideal “golden standard” characterization signature to a test structure characterization data set, based on a plurality of focus and exposure conditions.

Abstract: Disclosed is an imaging optical system and an image forming apparatus that provide a small-size design and high resolution. An optical system (telecentric optical system) between the composite focus 4d of an imaging surface side and a laser array 1 is divided into a second lens group 4b and a third lens group 4c and the distance D2 between the third lens group 4c and the laser array 1 is shortened, whereby the spread of incident light into the third lens group 4c is reduced and the aperture of the third lens 4c is reduced. Also, the principal light beam 2a of beam 2 from the laser array 1 is bent at two stages, the second lens group 4b and the third lens group 4c, and the distance D1 between the second lens group 4b and the third lens group 4c is increased, whereby the bend of the principal light beam 2a of the laser beam 2 in the second lens group 4b and the third lens group 4c is reduced, with the result that small aberration is obtained.

Abstract: A printing apparatus is disclosed which includes an original positioning device (3) for transporting an original (F) to and positioning it in a printing position, a printing material positioning device (2a) for transporting the photographic printing material (P) to and positioning it in an exposure position, a lighting device (4) for exposing the original, located in the printing position, to print light, an adjustable lens (5) for projecting the original, located in the printing position, onto the printing material located in the exposure position with an variable enlargement, a lens focusing device (6) for varying the enlargement of the lens (5), and a control device (10) for the original positioning device (3), the printing material positioning device (2a) and the lens focusing device (6).

Abstract: An enlargement lens is moved to a retracted position by driving a lens moving deck, and temporarily transferred onto a lens storing deck. After the lens moving deck is returned to its initial position, the enlargement lens is rotatably supported on support rails and rotated about its rotatable shaft to expose a lens surface to the outside for the cleaning. Accordingly, the enlargement lens can easily be cleaned.

Abstract: The pattern forming method is capable of forming a projected image or photoresist pattern that is faithful to a designed pattern without performing complex correction of a mask pattern. A projection exposure system and a semiconductor device fabrication method employing this pattern forming method are also disclosed. Exposure is performed by setting a pupil filter with a variable amplitude transmittance to the pupil position of the projection lens of a projection exposure system. The pupil filter has a transparent substrate, a phase retarding layer, a translucent film, and an opaque stencil. The pupil filter is replaced or rotated during either a plurality of exposures or during a single exposure onto the same position on the surface of a wafer substrate that is to be exposed. It is possible to improve the fidelity of the contour of a pattern transferred image without improving the numerical aperture (NA) of a projection lens, decreasing the wavelength of exposure light, or locally correcting a mask pattern.

Abstract: Disclosed is a method of determining a best focus position or best exposure amount of a projection lens in an arrangement wherein a reticle is placed on a plane perpendicular to an optical axis of the projection lens, wherein a pattern having periodicity in a predetermined direction is provided on a surface of the reticle, wherein the pattern is transferred to a photosensitive substrate by the projection lens to form a printed pattern thereon.

Abstract: A photographic copier has a copying station with a platen for a master to be reproduced and a platen for copy material. A straight guide extends across the copying station below the platen for the master and above the platen for the copy material, and a carrier is movable along the guide. The carrier supports several parallel rows of objectives, and the rows extend transverse to the direction of travel of the carrier. The objectives of each row have the same magnification and the magnification decreases successively from row to row, or vice versa. Each row is located at a different level of the carrier with the row of maximum magnification at the highest level and the row of minimum magnification at the lowest level. The objectives have vertical optical axes and the guide is inclined to the optical axes at an angle different from 90 degrees. The row of maximum magnification is disposed at the end of the carrier which faces the lower end of the guide.

Abstract: A lens loading apparatus for loading a lens held by a holding member into a lens loading unit disposed in the center of a support plate which extends substantially in a horizontal direction. The lens loading apparatus has a first reference surface formed in the upper surface of the support plate along a lens insertion direction and used for placing the holding member thereon. A second reference surface is formed on the support plate along the lens insertion direction and against which one end surface of the holding member, which extends along the lens insertion direction, abuts. The holding member, which is inserted from a horizontally-extending one end, is guided along the second reference surface by a first pressing member. Further, the holding member is guided along the first reference surface by a second pressing member, thereby making it possible to stably position the lens in a predetermined place.

Abstract: A photographing device includes a camera mounting unit on which a camera is detachably mounted, a light source unit arranged at a predetermined distance from the camera mounting unit, and a table which is arranged between the light source unit and the camera mounting unit, and on which an object is placed. The object placed on the table is illuminated by the light source unit, and can be photographed by the camera.

Abstract: A lens holder is pivotally mounted at its one end on an axle, and is movable up and down along the axle. The lens holder has a fork formed in the other end. The fork and an arched holding member form an oval aperture. A zoom lens is rotatably fitted in the oval aperture, and also is slidable therein in a horizontal direction. When removing the zoom lens from a lens deck, a lens board securely holding the zoom lens is pulled away from the lens deck in a straight line. The zoom lens rotates and slides in the oval aperture while moving along with the pivotal movement of the lens holder. To move the zoom lens into a rest position, the lens holder pivots further about the axle.

Abstract: A lithographic device with a lithographic irradiation system (1, 13) which is fastened near a lower side to a mounting member (5) of a frame (7). The device is provided with a unit (65) which is formed by a positioning device (37), with which an object table (21) arranged below the irradiation system (1, 13) is displaceable, and by a support member (35), over which the object table (21) is guided by means of an aerostatic foot (31). In an operational position, the unit (65) is coupled to a carrier (67) by means of coupling members (73), the carrier (67) being suspended from the mounting member (5) by means of suspension elements (79, 81, 83), so that the unit (65) is arranged between lower frame supports (25) of the frame (7) and a compact construction is obtained.The unit (65) can be rotated from the operational position to an end position, in which the unit (65) is entirely outside the frame (7) and is easily accessible for maintenance, by means of a rotation mechanism (87) and a swivel mechanism (89).

Abstract: A light-and pressure-sensitive recording sheet and an original, overlapping each other, are introduced into an image forming apparatus, and are exposed to radiation on a transparent drum by means of a light source in the drum, whereupon a latent image, based on the contents of the original, is formed on the recording sheet. Then, the recording sheet is separated from the original by means of a separator, and is passed between a pair of pressure rolls. When the recording sheet is exposed, microcapsules thereon change their hardness. These microcapsules are ruptured selectively by pressure applied to the sheet. As a result, a chromogenic material, contained in the microcapsules, and a developer material, on the surface of a substrate of the recording sheet, react with each other, so that the sheet surface changes its color. Thus, the latent image is developed to accomplish copying in accordance with the original.

Abstract: A projecting apparatus comprises support device for supporting an original, a projection optical system for forming the image of the original, an optical element disposed on the image side of the projection optical system to cause a principal light ray having entered from the original through the projection optical system to travel in parallelism to the optic axis of the projection optical system, and control device for varying the imaging magnification of the original by the projection optical system with the spacing between the exit pupil of the projection optical system and the optical element being kept constant.

Abstract: A projection optical system for photolithography includes a refraction sub-system and a cata-dioptric sub-system optically connected to each other. The refraction sub-system extends at an object side. The cata-dioptric sub-system extends at an image side. The refraction sub-system is generally composed of refracting members. The cata-dioptric sub-system is generally composed of a phase compensating member, a concave mirror, and a convex mirror. The phase compensating member adjoins the refraction sub-system. At least the concave mirror has a central opening through which light passes. The light forms an image at a rear of the concave mirror.

Abstract: An optical recording apparatus includes an imaging member which is advanced along a predetermined path, an optical recording head for applying light containing image information to the imaging member to form an electrostatic latent image thereon, a developing unit for developing the latent image thereby converting it into a toner image and a transfer unit for transferring the toner image to a sheet of transfer paper. With the imaging member in the form of a belt, a back-up member and a contact member, preferably in the form of brush, are provided on both sides of the belt-shaped imaging member in the vicinity of an image exposing section where the light from the recording head is applied to the imaging member thereby allowing that portion of the imaging member which is located in the image exposure section is prevented from moving up and down with respect to the advancing direction of the imaging member.

Abstract: The camera head of a planetary camera system is movably mounted on a frame of the system. Film members (e.g. aperture cards) are exposed in the camera head. A stationary film-processing station is mounted on the frame in a position remote from the camera head and is linked to the camera head by a light-tight extensible film member conveying means. Telescopic tubes containing endless conveyor belts of variable effective length are preferred for the conveying means.

Abstract: In a color-slide duplicator having a housing containing a light source which illuminates an opening in a housing wall, and a support for a camera above the housing for photographic reproduction of a slide to be duplicated; an assembly for supporting the slide comprises a carrier plate releasably and adjustably secured by magnets to the housing wall so as to span the illuminated opening which registers, at least in part, with an aperture in the carrier plate, and first and second parallel guide bars having undercut, beveled edges facing toward each other and being arranged on the carrier plate at opposite sides of the aperture in the latter, with one of the guide bars being movable laterally and resiliently urged in the direction toward the other guide bar, such guide bars being included in a quick-release mechanism by which the slide to be duplicated is positioned and held against the carrier plate over the aperture therein.

Abstract: Apparatus for producing an enlargement of a graphic image including a light tight housing having an extended hollowed out central area and a light tight aperture located at one end thereof which is adapted to receive and pass a graphic image to be enlarged to a predetermined location along the center axis of and at one end of the hollowed out housing, a lens shroud including a planar lens support having a fixed focal length lens located in the center thereof and sidewalls extending therefrom and positioned with the fixed focal lens located adjacent the predetermined location and wherein the lens shroud is moveable within the hollowed out central area over a preselected distance to position the fixed focal length lens at any location within the preselected distance and in alignment with the predetermined location, a gantry housing, including sidewalls for defining a passageway which terminates in an opening at one end thereof and a planar matt support at the other end thereof wherein the gantry housing is move

Abstract: In a photographic enlarger apparatus having a carriage operatively connected to a vertical column for movement thereon to a selected position, an alignment structure is provided for maintaining the carriage in three-dimensional alignment with the column. In one embodiment, a roller captively eccentrically journaled in the front of the carriage is biased against one face of the column to maintain the carriage in axial alignment with respect thereto. Further alignment of the carriage with respect to the column is provided by four wheels mounted in the back of the carriage to rotatably engage opposed channels formed in the rear of the column, two vertically aligned wheels being spring-biased against one channel and coacting with two vertically aligned fixed wheels riding in an opposite channel to urge the carriage into constant lateral alignment.

Abstract: An apparatus for making a photographic reduction of various sized film negatives having a light box, a camera spaced within a housing a positioned above said light box, a removable film container, with film mounted therein, being attached in optical communication with said camera; said camera comprising a first lens, and exposure control means, a second lens, a third and fourth lens of different focal lengths mounted above said second lens, being individually pivotally positioned within said camera from a first position out of optical alignment with said first and second lenses to a second position in optical alignment with said first and second lenses.

Abstract: An apparatus and method for resizing artwork by using in combination with a headline setter device, an apparatus which allows the headline setter device to be used in addition to its normal typesetting function, to resize existing artwork.

Abstract: A system for close-up and copy photography is so designed that a zoom lens whose total barrel length remains unchanged during zooming operation is attached to a camera as the master lens with an adapter being attached to the zoom lens and with a fixed focus lens being attached to the adapter on the side opposite the side to which the zoom lens is attached. The fixed focus lens is arranged in a position reversed from the position in which it would normally be used, that is, with its object side facing the zoom lens and with its image side facing toward an object to be photographed. The adapter may have a filter mount mechanism and a securing stand attached to the adapter for holding an object to be photographed is structured to permit illumination of the object.

Abstract: An optical system for projecting patterns in order to reproduce the image of at least one modulating object on a mask or semiconductor wafer coated with photosensitive material for the fabrication of semiconductor components. In this system, optical reflecting means comprising one or a number of plane mirrors including at least one movable mirror are introduced in the optical path of the imaging objective. By forming additional optical paths, it is thus possible to associate with a photorepetition function different functions such as photocomposition or other photorepetition paths, or else to associate a device for ensuring alignment of the object-image planes and comprising optoelectronic detection means.

Abstract: An optical system for forming a spot object or an arcuate object into an arcuate image or a spot image. This optical system has a band-like spherical mirror obtained by sectioning a concave spherical mirror. By the band-like spherical mirror, the spot object disposed on the rotational symmetry axis other than the center of curvature may be imaged into an arcuate form on a certain surface perpendicular to the rotational symmetry axis. Conversely, an arcuate object on said certain surface may form a spot image at the position whereat the spot object is disposed.

Abstract: A photographic printing or enlarging apparatus incorporates a negative carrier, a lens stage, and a positioning device for positioning the lens stage toward and away from a negative carrier. The positioning device comprises a body and one or more push rods each of which is mounted on, and releasably secured to, the body for movement in the direction of its length. A selected push rod is positioned to engage the lens stage, or a part of the apparatus connected to the lens stage, to fix the position of the stage relative to the negative carrier in accordance with the predetermined setting of the selected push rod. The positioning device may incorporate a plurality of push rods or may incorporate a single push rod that may selectively be extended and locked in an extended position to contact a portion of the apparatus connected to the lens stage for fixing the distance between the lens stage and the negative carrier.

Abstract: An apparatus for producing an enlargement of a graphic image having a light tight housing with an opening on one side of the housing which cooperates with a light tight door to provide access to a central area of the housing, a platen adapted to receive a graphic image to be enlarged at the bottom of the housing, at least one set of parallel space lens support slots fixed to the housing and positioned one slot on each side of the hollowed out area and located a preselected distance from the platen, at least one set of parallel space slots fixed to the housing and positioned one slot on each side of the housing at the upper end of the housing with the parallel space and support slots and the platen located thereunder, a planar lens support having a fixed focal length lens adapted to be slidably inserted into and supported by at least one set of lens supports to position the lens between the platen and the base support slots, a planar matt support of a selected dimension positioning a sensitized sheet material

Abstract: A platform-shaped device is designed to be placed over the illuminating aperture of a color-controllable light-box of known construction, and under a camera which is loaded with a roll of color film of slide-forming size and character, and which is focused on the central area of the platform. The device has at opposite sides a reel for holding, guidedly feeding and receiving a roll of developed black-and-white negatives previously made from the usually much larger black-and-white art work. The device also has means (e.g. a geneva-movement mechanism) for accurately sequentially positioning in the camera field, each one of a series of frames to be converted to color-slide frames in the camera. A pair of laterally movable thin blackened masking plates are manually movable in guides to expose different laterally constricted areas of the negative for each color to be projected therethrough from the light-box.

Abstract: An enlargement lens system has a light guide element positioned in the gap between the outer periphery of a rear lens group frame and a lens mount. A dispersion lens is provided on a portion of the rear lens and a transmission window is disposed on the rear lens frame. Light inside the effective area of the lens passes through the dispersion surface and the transmission window onto the light guide. The reflex surface on the guide reflects light onto the lens stop-value scale.

Abstract: A microfilm camera is provided which has a camera head positioned above an exposure table. The exposure table included a pivotable glass plate and originals to be photographed can be placed beneath the glass plate or on its upper surface. To enable in-focus pictures of originals in either position to be taken, means are provided to vary the distance between the film in the camera head and the glass plate. In one embodiment the exposure table is mounted on four columns each having a lifting cam operated by a common activating handle. In a second embodiment the camera head can be raised or lowered by a handle operated eccentric cam.

Abstract: A projector for visual images which may be used for projection upon its own base or a wall. The projector has a base, an upstanding column, an adjustable arm and a projection housing. The projector is battery powered and the batteries are connected to the projection lamp through contacts disposed on the base and in the vertical column. The projector is operable at any column height setting.

Abstract: A device for displacing a body along a guiding column which is particularly suitable for the projection head of an enlarging or reproducing apparatus. The device comprises in a conventional manner a guiding column and, on the body, a friction wheel which presses against the column and which is disposed on a shaft. The shaft of the friction wheel is mounted in the sleeve-like body which surrounds the column except in the vicinity of the friction wheel. The friction wheel is sub-divided into two wheel portions and means are provided for exerting a force upon the wheel portions along the axis of the friction wheel. These means act upon a guiding surface of the column disposed at an angle of up to 90.degree. with respect to the friction wheel axis.

Abstract: A system for exposing photoresists "on-the-fly" is disclosed. The system incorporates a dye laser having an output pulse duration of less than about 250 nanoseconds to expose the photoresist while the photoresist is moving. Means are provided to synchronize the output of the laser to the motion of a photoresist coated surface and to insure spatial uniformity of energy across an object plane of an optical projection system.

Abstract: This improved photocopying system projects light from the finder of a camera and through the camera lens to illuminate, on a copy support, the exact area that the camera will photograph. The material to be copied is composed accurately in the illuminated field, the copy lights are turned on, and the camera is operated to make a photocopy. Optical fibers are used to supply light to the finder without overheating the camera.

Abstract: Apparatus for use in the production of a colored photographic reproduction of a black and white negative which consists essentially of a light-free enclosure, a baffle having an aperture and extending across the housing with means to mount the black and white negative over the aperture, means to carry one or more colored filters and means to generate a pulse of light to illuminate the negative in order that a copy may be taken by a camera suitably mounted.

Abstract: An anti-backlash means, particularly adapted for photographic enlargers including a channel shaped optical bench having a pair of guideways; a frame movable along the guideways, having a pair of tracks, a pair of rack elements, and leaf springs supporting the rack elements in continuous relation; a gear rotatably supported by the optical bench including a pair of gear elements engageable with the rack elements, and wheels riding on the tracks to maintain a fixed minor spacing between the pitch plane of the rack elements at the pitch radius of the gear elements; either the gear elements or the rack elements having offset teeth to eliminate backlash.