Abstract: A laser processing device includes a setting device that sets an irradiation condition of laser light, and a first storage that stores the set irradiation condition. The setting device sets different irradiation conditions respectively for cells included in test cells. A verification device captures an image of the processing pattern and calculates luminance values for the cells respectively. The setting device sets at least one of the irradiation conditions for main processing, based on information on luminance values of the test cells extracted from the luminance values for the cells and based on the irradiation conditions set for the test cells.

Abstract: There is provided a laser machining device including a heat radiation measurement unit that measures intensity of heat radiation of a workpiece irradiated with a laser beam, and a determination unit that determines a state of a target by defining an object used in machining work as the target, based on the intensity of the heat radiation measured by the heat radiation measurement unit.

Abstract: An irradiation device for additively manufacturing three-dimensional objects may include a beam generation device configured to generate an energy beam, an optical modulator including a micromirror array disposed downstream from the beam generation device, and a focusing lens assembly disposed downstream from the optical modulator. The micromirror array may include a plurality of micromirror elements configured to reflect a corresponding plurality of beam segment of the energy beam along a beam path incident upon the focusing lens assembly. The focusing lens assembly may include one or more lenses configured to focus the plurality of beam segments such that for respective ones of a plurality of modulation groups including a subset of micromirror elements, a corresponding subset of beam segments are focused to at least partially overlap with one another at a combination zone corresponding to the respective modulation group.

Abstract: A spectroscopic analysis device includes: a film that contacts a sample subject to spectroscopic analysis; a first irradiator that irradiates a first irradiation light having transition energy to decompose attached material attached to a boundary surface of the film; and an optical waveguide that transmits the first irradiation light irradiated from the first irradiator. A first evanescent wave, based on the first irradiation light, is generated on a front surface of the optical waveguide, and is then projected on an attached region of the attached material.

Abstract: Systems and methods of a laser welding device are disclosed. The laser welding device includes a laser generator configured to generate welding-type lasing power. A lens focuses the welding-type lasing power at a focal point on a workpiece to generate a puddle during a welding-type operation. A wire feeder is configured to feed wire to the puddle generated by the laser generator. A laser scanner controls the lens to move the focal point of the welding-type lasing power in multiple dimensions over the workpiece during the welding-type operation. In some examples, the feed wire is used in an additive manufacturing process.

Abstract: A build unit for additively manufacturing three-dimensional objects may include an energy beam system having one or more irradiation devices respectively configured to direct one or more energy beams onto a region of a powder bed, and an inertization system including an irradiation chamber defining an irradiation plenum, one or more supply manifolds, and a return manifold. The one or more supply manifolds may include a downflow manifold configured to provide a downward flow of a process gas through at least a portion of the irradiation plenum defined by the irradiation chamber, and/or a crossflow manifold configured to provide a lateral flow of the process gas through at least a portion of the irradiation plenum defined by the irradiation chamber. The return manifold may evacuate or otherwise remove process gas from the irradiation plenum defined by the irradiation chamber.

Abstract: A manipulator device such as a robot arm that is capable of increasing manufacturing throughput for additively manufactured parts, and allows for the manipulation of parts that would be difficult or impossible for a human to move is described. The manipulator can grasp various permanent or temporary additively manufactured manipulation points on a part to enable repositioning or maneuvering of the part.

Abstract: A visible light laser system and operation for welding materials together. A blue laser system that forms essentially perfect welds for copper based materials. A blue laser system and operation for welding conductive elements, and in particular thin conductive elements, together for use in energy storage devices, such as battery packs.

Abstract: The present invention discloses a composite device for high-precision laser additive/subtractive manufacturing, which consists of a sealed shaping chamber, an inert protective gas source and a machine-shaping platform; wherein, the inert protective gas source is connected to the sealed shaping chamber; and the machine-shaping platform is arranged in the sealed shaping chamber, as well as there is a light path selection system is arranged right above the machine-shaping platform; in addition, there is a machining position is equipped on the machine-shaping platform, meanwhile, there are lead screws are arranged under the machine-shaping platform.

Abstract: Provided is a rectifier device for a vehicle alternator including a rectifying element for rectifying in an alternator. The rectifying element has an Enhanced Field Effect Semiconductor Diode (EFESD). The EFESD includes a lateral conducting silicide structure and a field effect junction structure integrating side by side. A rectifier, a generator device, and a powertrain for a vehicle are also provided.

Abstract: The inventive concept relates to a substrate cooling apparatus for cooling a substrate. The substrate cooling apparatus includes a chuck on which the substrate is placed and a cooling unit that cools the chuck. The cooling unit includes a heat dissipation plate that has the chuck placed on an upper surface thereof and that dissipates heat of the chuck.

Abstract: A scanner includes a light source configured to apply a light to a backside of a wafer. The light is reflected from the backside of the wafer. A first mirror is configured to receive the light from the backside of the wafer and reflect the light. A sensor is configured to receive the light from the first mirror and generate an output signal indicative of a backside topography of the wafer.

Abstract: Intraocular implants and methods of making intraocular implants are provided. The intraocular implants can improve the vision of a patient, such as by increasing the depth of focus of an eye of a patient. In particular, the intraocular implants can include a mask having an annular portion with a relatively low visible light transmission surrounding a relatively high transmission central portion such as a clear lens or aperture. This construct is adapted to provide an annular mask with a small aperture for light to pass through to the retina to increase depth of focus. The intraocular implant may have an optical power for refractive correction. The intraocular implant may be implanted in any location along the optical pathway in the eye, e.g., as an implant in the anterior or posterior chamber.

Abstract: A laser treatment device performing treatment by irradiating a target object having a plate surface with laser light, including: a light-transmitting region transmitting laser light emitted onto the target object; a rectifier that has a rectifier surface separated from the target object and extending along the plate surface of the target object and outward from the end of the light-transmitting region; a gas supply unit that feeds a gas to a gap between one side of the rectifier surface and the light-transmitting region, in a position separated from the light-transmitting region; and a gas exhaust unit that exhausts, on the other side that is on the other side of the light-transmitting region from the one side, the gas present in a gap between the rectifier surface and the target object from the gap, in a position separated from the light-transmitting region, thereby generating a stable local gas atmosphere.

Abstract: A method for producing an ophthalmic lens includes a step of laser marking in order to produce permanent etchings on one surface of the lens, at least one predefined step subsequent to the marking step and implementing extreme thermal stress that is applied to the surface, and a step of determining an operating point (PF) of a laser marking machine (1) configured to implement the marking step from geometric characteristics (Di) of the etchings to be made, the determining step including the steps of determining (304) a value (CPM) representative of the deformation of the lens on at least one treatment area of the surface, from the stress and data relative to a predetermined material from which the lens is formed, and of deducing (308) the operating point from the value representative of deformation and from the geometric characteristics.

Abstract: Embodiments of the present disclosure provide a sintering device and a sintering method thereof. The sintering device includes: a housing, defining a chamber; and at least one first heating mechanism and at least one second heating mechanism, disposed in the chamber, wherein the at least one first heating mechanism and the at least one second heating mechanism provide different heating temperatures for a workpiece to be processed.

Abstract: There are provided: a plurality of optical elements for handling light having different wavelengths; a plurality of collimating lenses individually provided in the optical elements, each of the collimating lenses having a first end facing a main surface of one of the optical elements; an optical multi-demultiplexer using reflection of light caused by a spatial optical system, the optical multi-demultiplexer having a first end facing a second end of each of the collimating lenses; a coupling lens having a first end facing a second end of the optical multi-demultiplexer; an SMF having one end facing a second end of the coupling lens; and an optical block, which is transparent, provided on an optical path between each of the collimating lenses and the optical multi-demultiplexer, the optical path having a small number of reflections in the optical multi-demultiplexer.

Abstract: The disclosure relates to a methods and devices for producing three-dimensional objects by a beam acting on and selectively solidifying a construction material applied layer by layer. The devices include at least one process chamber, which has a building platform on which the three-dimensional object is created, a radiation source for producing the beam, at least one beam guiding element, and a process assisting device movable above the building platform and having a first and second module with a beam guiding portion arranged between for the beam that is directed onto the building platform. Each module has at least one application device for discharging construction material and a monitoring device with at least one sensor element for sensing the applied and solidified layer of construction material.

Abstract: Various embodiments of the present invention relate to a method for welding a workpiece comprising the steps of: making a first weld at a first position on said workpiece with a high energy beam, deflecting the high energy beam with at least one deflection lens for making a second weld at a second position on said workpiece, focusing the high energy beam on said workpiece with at least one focusing lens, shaping the high energy beam on said workpiece with at least one astigmatism lens so that the shape of the high energy beam on said workpiece is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam. The invention is also related to the use of an astigmatism lens and to a method for forming a three dimensional article.

Abstract: Laser lift off systems and methods overlap irradiation zones to provide multiple pulses of laser irradiation per location at the interface between layers of material to be separated. To overlap irradiation zones, the laser lift off systems and methods provide stepwise relative movement between a pulsed laser beam and a workpiece. The laser irradiation may be provided by a non-homogeneous laser beam with a smooth spatial distribution of energy across the beam profile. The pulses of laser irradiation from the non-homogenous beam may irradiate the overlapping irradiation zones such that each of the locations at the interface is exposed to different portions of the non-homogeneous beam for each of the multiple pulses of the laser irradiation, thereby resulting in self-homogenization. Thus, the number of the multiple pulses of laser irradiation per location is generally sufficient to provide the self-homogenization and to separate the layers of material.

Abstract: A thermal processing apparatus and method in which a first laser source, for example, a CO2 emitting at 10.6 ?m is focused onto a silicon wafer as a line beam and a second laser source, for example, a GaAs laser bar emitting at 808 nm is focused onto the wafer as a larger beam surrounding the line beam. The two beams are scanned in synchronism in the direction of the narrow dimension of the line beam to create a narrow heating pulse from the line beam when activated by the larger beam. The energy of GaAs radiation is greater than the silicon bandgap energy and creates free carriers. The energy of the CO2 radiation is less than the silicon bandgap energy so silicon is otherwise transparent to it, but the long wavelength radiation is absorbed by the free carriers.

Abstract: A method for printing an object using a high power one-dimensional (1D) line laser imager for selective laser sintering of thermal plastics. The technique is a two-step process. First, a layer of fresh powder is deposited on top of an existing powder bed. Second, the powder is sintered with the line laser print head. The laser is modulated at the source or with a spatial light modulator. Multiple passes or imagers can be used for increased part width and productivity. Using the relative travel between energy receiving surface and the laser print head in the direction perpendicular to the laser imaging line, a 2D pattern is imaged. Multiple print head can be aligned and joined to form a wider laser print head.

Abstract: The invention discloses a Selective Laser Melting forming device for multiple metal powder materials. Technical solutions adopted are as follows: a collector container, a build cylinder and a feed container are provided on a lower portion of a process chamber; leveling oil cylinders for the substrate are mounted in the build cylinder; a recoater bracket in the process chamber is slidably mounted on a slide rail; a recoater is fixed on a lower portion of the recoater bracket; a compaction roller is simultaneously mounted on the recoater bracket; a stress sensor is provided under the compaction roller; an electron microscope for collecting the porosity of the spread powder and the product and a melting pool monitoring Charge Coupled Device camera; a laser scanning system, a directional heating laser system and an alarm device are provided on a top portion of the process chamber.

Abstract: Provided is a method for manufacturing a formed article that excels in shape retainability and appearance, using a sheet that contains a thermoplastic resin fiber and a continuous reinforcing fiber. The method for manufacturing a formed article comprises irradiating laser light onto a sheet having, arranged therein with a certain directionality, yarns that contain a thermoplastic resin fiber and a continuous reinforcing fiber, so as to allow at least a part of the thermoplastic resin fiber to be impregnated into the continuous reinforcing fiber; the laser light being irradiated so as to satisfy at least one of A or B below, over at least 70% or more of the laser irradiation area; A: irradiated in a direction 5 to 85° away from the direction of arrangement of yarns in the in-plane direction of the sheet; and B: irradiated in a direction 30 to 60° away from the direction perpendicular to the sheet plane.

Abstract: A method for forming a coating system on a component includes depositing a reactive layer with predetermined CMAS reaction kinetics on at least a portion of a thermal barrier coating. The method also includes activating the reactive layer with a scanning laser. A component, such as a gas turbine engine component, includes a substrate, a thermal barrier coating and a reactive layer. The thermal barrier coating is deposited on at least a portion of the substrate. The reactive layer is deposited on at least a portion of the thermal barrier coating. The reactive layer has predetermined CMAS reaction kinetics activated by laser scanning.

Abstract: A remanufacturing method for a metal part having a damage. The damage groove is divided into a number of levels, and the groove bottom is treated by absorption layer-free laser shock peening to remove surface impurities and to refine surface-layer crystal grains. Then a cladding layer is formed by laser cladding. The process is repeated until the groove is completely filled by the cladding layer to higher than the surface of the metal part and the cladding layer higher than the surface is cut by a mechanical processing and polished, and the upper surface of the laser cladding layer is subjected to large-area overlapped laser shock peening.

Abstract: A method of bonding a flexible part including inclined leads is provided, and more particularly, a method of bonding a flexible part including inclined leads, in which parts are aligned to bond the parts is provided. According to the method of bonding the flexible part including inclined leads, an electronic part may be easily bonded to a part having an inclined surface.

Abstract: Additive manufacturing systems are disclosed. The systems may include a base, and a retaining plate coupled to the base. The retaining plate may include a seat formed in an exposed surface of the retaining plate, and a plurality of pads extending laterally into the seat. The additive manufacturing systems may also include a build plate positioned within the seat and contacting the plurality of pads of the retaining plate. The build plate may include a build surface in substantial planar alignment with the exposed surface of the retaining plate. Additionally, the additive manufacturing systems may include a plurality of build plate retention components positioned in the seat of the retaining plate. Each of the plurality of build plate retention components may be utilized to retain the build plate within the seat of the retaining plate.

Abstract: A laser processing apparatus including a processing nozzle for irradiating a workpiece with laser beam, a driving mechanism for relatively moving the processing nozzle and the workpiece, and a gap sensor for detecting a gap between the processing nozzle and the workpiece. The apparatus includes a gap control section referring to a measured value detected by the gap sensor and calculating a manipulating variable used for controlling the driving mechanism so as to maintain the gap during execution of laser processing at a first dimension, a power monitoring section monitoring electric power from a power supply and sending an abnormality detection signal to the gap control section when a power abnormality occurs, and a control action switching section switching a control action of the gap control section so as to increase the gap from the first dimension when the abnormality detection signal is sent to the gap control section.

Abstract: The invention is a method and an apparatus for marking an article and the article thus marked. It includes providing the article. Generating a plurality of groups of laser pulses. At least one of the plurality of groups is generated by modulating a beam of laser pulses to form a plurality of beamlets. Each, of the plurality of beamlets, include at least one laser pulse. It also includes directing the plurality of groups of laser pulses onto the article such that laser pulses within the at least one of the plurality of groups impinge upon the article at spot areas that do not overlap one another, wherein laser pulses within the plurality of groups are configured to produce a visible mark on the article.

Abstract: A method for removing a metal from a single-thread fabric for making a pattern, characterized in that said single-thread fabric is a square-mesh metallized and etching laser made fabric.

Abstract: A laser machining apparatus includes a laser nozzle for supplying an assistive gas to remove undesirable materials and applying a laser beam at an angle, which is inclined with respect to a surface of a workpiece, a sputter blocking jig disposed over a region of the workpiece that is irradiated with the laser beam, so as to lie across directions in which the laser beam is scattered, and for blocking sputtered particles that are generated from the surface by the applied laser beam, and a joint connecting the laser nozzle and the sputter blocking jig to each other. The joint moves the laser nozzle and the sputter blocking jig in synchronism with each other.

Abstract: A system for registering a three dimensional map of an environment includes a data collection device, such as a robotic device, one or more sensors installable on the device, such as a camera, a LiDAR sensor, an inertial measurement unit (IMU), and a global positioning system receiver. The system may be configured to use the sensor data to perform visual odometry, and/or LiDAR odometry. The system may use IMU measurements to determine an initial estimate, and use a modified generalized iterative closest point algorithm by examining only a portion of scan lines for each frame or combining multiple feature points across multiple frames. While performing the visual and LiDAR odometries, the system may simultaneously perform map registration through a global registration framework and optimize the registration over multiple frames.

Abstract: Described herein is a method of producing an alloy. The method includes pouring a stream of molten mixture of component elements of the alloy, separating the stream into discrete pieces, solidifying the discrete pieces by cooling before the discrete pieces contact any liquid or solid. Also described herein is another method of producing an alloy. This method includes pouring and solidifying a stream of molten mixture of component elements of the alloy into a rod or pulling a rod from a molten mixture of component elements of the alloy, before the rod contacts any liquid or solid, separating the rod into discrete pieces. An apparatus suitable for carrying out the methods above can include a container from which the molten stream is poured or the solid rod extends, one or more coil, conductive plates, a laser source, or an electron beam source arranged around the molten stream or the solid rod and configured to separate the molten stream or the solid rod into discrete pieces.

Abstract: In a method for manufacturing an article (1), particularly a prototype of a product or component, a tool prototype or spare part, by using selected laser melting, for the application onto the article (1) of a layer (13) or portion of a second metallic material, which is different from the material of the first metallic powder (4), a tape (12), sheet (14), foil or three-dimensional pre-form (18) of a second material is applied to the article (1) and is heated by a focused laser or electron beam (6) to a specified temperature such that the tape (12), sheet (14), foil or pre-form, respectively, are made molten by the electron laser beam (6), wherein the focused beam (6) is applied to a given area corresponding to a selected cross-sectional area of the model of the article (1) under formation of a new layer or part made of second material integral with the article (1).

Abstract: A system for registering a three dimensional map of an environment includes a data collection device, such as a robotic device, one or more sensors installable on the device, such as a camera, a LiDAR sensor, an inertial measurement unit (IMU), and a global positioning system receiver. The system may be configured to use the sensor data to perform visual odometry, and/or LiDAR odometry. The system may use IMU measurements to determine an initial estimate, and use a modified generalized iterative closest point algorithm by examining only a portion of scan lines for each frame or combining multiple feature points across multiple frames. While performing the visual and LiDAR odometries, the system may simultaneously perform map registration through a global registration framework and optimize the registration over multiple frames.

Abstract: A device and method for detecting crystal quality of a low temperature poly-silicon (LTPS) backplane are provided, the method including: projecting narrowband light to the LTPS backplane; performing image capturing of each position on a surface of the LTPS backplane at a first angle in a first axial direction to obtain a first diffraction image, the first angle being an angle of maximum diffraction light intensity in the first axial direction; performing another image capturing of each position on the surface of the LTPS backplane at a second angle in a second axial direction to obtain a second diffraction image, the second angle being an angle of maximum diffraction light intensity in the second axial direction; and determining the crystal quality of the LTPS backplane based on a diffraction light intensity distribution obtained from the first and second diffraction images.

Abstract: Methods, devices and systems for laser-supported plasma cutting or plasma welding of a workpiece. In one aspect, a method includes producing a plasma beam which extends in an expansion direction between an electrode and a processing location on the workpiece, the plasma beam having, with respect to a center axis of the plasma beam that extends in the expansion direction, an inner central region and an outer edge region, and supplying laser radiation to the outer edge region of the plasma beam. The laser radiation supplied to the outer edge region extends parallel with the center axis of the plasma beam.

Abstract: A coating arrangement (16), including: a layer (18) of bond coat material (20); and a light-transmissive thermal barrier coating (TBC) mesh (28) having a TBC material (24) and secured in position relative to the layer of bond coat material. The coating arrangement may be positioned over a superalloy substrate material (12) and melted with a laser beam (62) to metallurgically bond the thermal barrier coating onto the substrate.

Abstract: Presented is a method for forming at least one structure on a substrate. Utilizing a low-temperature plasma jet, powder, of which the structure shall be constructed, is applied to a surface of the substrate. Using at least one laser beam, heat is input into the substrate and/or the powder within a laser incidence region on the substrate. The heat input delays solidification of the powder particles, which are partly or fully melted in the plasma jet, on the substrate and thereby enables the formation of good adhesion between the applied powder, and thus the structure constructed out of the powder, and the substrate. The invention further relates to an apparatus for performing the method.

Abstract: A method of establishing a boundary for a material improvement process on a workpiece is disclosed. The method may include identifying a maximum allowable damage depth on the workpiece; identifying a maximum constant thickness line on the workpiece at an extent of the maximum allowable damage depth; identifying a peak vibratory stress gradient on the workpiece; identifying a peak combined engine stress on the workpiece; and specifying the boundary for the material improvement process on the workpiece relative to the maximum constant thickness line, peak vibratory stress gradient, and peak combined engine stress.

Abstract: Method and system for controlled nanodiamond synthesis based on treating of a specially prepared solid carbon source target including carbon containing material in liquid media by irradiation energy beam focused at a predetermined distance from the target surface and having parameters to produce a light-hydraulic effect impacting the target surface and leading to the forming of diamond nanocrystals.

Abstract: Provided is a testbed for conducting an experiment on a substance in a cryogenic liquid state in a microgravity environment. Such a testbed includes a frame with rectangular nominal dimensions, and a source section supported by the frame for supplying the substance to be evaluated in the cryogenic liquid form. An experiment supported by the frame includes an experiment vessel in fluid communication with the storage tank to receive and condense the substance into the cryogenic liquid state. A sensor senses a property of the cryogenic liquid in the experiment vessel as part of the experiment, and a bus section includes a controller configured to control delivery of the substance to the experiment vessel, and receives property data indicative of the property sensed by the sensor for subsequent evaluation on Earth.

Abstract: If an optical path length of an optical system is reduced and a length of a laser light on an irradiation surface is increased, there occurs curvature of field which is a phenomenon that a convergent position deviates depending on an incident angle or incident position of a laser light with respect to a lens. To avoid this phenomenon, an optical element having a negative power such as a concave lens or a concave cylindrical lens is inserted to regulate the optical path length of the laser light and a convergent position is made coincident with a irradiation surface to form an image on the irradiation surface.

Abstract: A method of reshaping a turbine engine blade including at least one deformed zone, the method including peening the deformed zone to be able to restore a shape of the at least one deformed zone.

Abstract: A method of assessing discrepancy between a target value and a measured value of a parameter of contact area produced between flow of solder ejected from a nozzle and a surface is defined in the present application. This method comprises the steps of: providing a surface of material through which contact area between solder ejected from a nozzle and a side of the surface can be visually detected, for example using a camera; flowing solder through a nozzle and then bringing the solder into contact with a side of the surface, thereby creating contact area between the solder and said side of the surface; detecting the contact area from the other side of the surface so that a value of a parameter of said contact area can then be measured; and assessing any discrepancy between the target value and the measured value so that any necessary compensation in order to achieve the target value can be programmed.

Abstract: A method of establishing a boundary for a material improvement process on a workpiece is disclosed. The method may include identifying a maximum allowable damage depth on the workpiece; identifying a maximum constant thickness line on the workpiece at an extent of the maximum allowable damage depth; identifying a peak vibratory stress gradient on the workpiece; identifying a peak combined engine stress on the workpiece; and specifying the boundary for the material improvement process on the workpiece relative to the maximum constant thickness line, peak vibratory stress gradient, and peak combined engine stress.

Abstract: Described herein are photonic systems and devices including a optical interface unit disposed on a bottom side of a photonic integrated circuit (PIC) to receive light from an emitter of the PIC. A top side of the PIC includes a flip-chip interface for electrically coupling the PIC to an organic substrate via the top side. An alignment feature corresponding to the emitter is formed with the emitter to be offset by a predetermined distance value; because the emitter and the alignment feature are formed using a shared processing operation, the offset (i.e., predetermined distance value) may be precise and consistent across similarly produced PICs. The PIC comprises a processing feature to image the alignment feature from the bottom side (e.g., a hole). A heat spreader layer surrounds the optical interface unit and is disposed on the bottom side of the PIC to spread heat from the PIC.

Abstract: An integrated laser material processing cell allowing laser-assisted machining to be used in conjunction with directed material deposition in a single setup, achieving greater geometric accuracy and better surface finish than currently possible in existing laser freeform fabrication techniques. The integration of these two processes takes advantage of their common use of laser beam heat to process materials. The cell involves a multi-axis laser-assisted milling machine having a work spindle, a laser emitter, and means for positioning the emitter with respect to the spindle so as to direct a laser beam onto a localized area of a work piece in proximity to a cutting tool mounted in the spindle. A powder delivery nozzle mounted on the machine and positioned adjacent to the emitter delivers powder to a deposition zone in the path of the beam, such that material deposition and laser-assisted milling may be performed substantially simultaneously in a single workspace.

Abstract: Method for the microdeformation of the front face of a thin part, by modifying the rear face or the periphery of the part. According to the invention, which can notably be used to correct the wave surface of a mirror, a local treatment is applied to the rear face or to the periphery which causes a static microdeformation, which is frozen once and for all, of the front face, without applying any mechanical force to the part.