Electric heating – Metal heating – By arc
Reexamination Certificate
2002-06-13
2003-12-16
Elve, M. Alexandra (Department: 1725)
Electric heating
Metal heating
By arc
Reexamination Certificate
active
06664501
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods for producing laser-induced color images inside three-dimensional photographic media by using pulsed laser radiation.
BACKGROUND OF THE INVENTION
A number of techniques for creation of colored images inside of transparent substrates by using natural light radiation and for production of laser-induced images created by pulsed laser radiation are well known.
U.S. Pat. No. 2,326,012 to Dalton discloses methods of producing color inside glasses and more particularly methods of making a glass article which includes melting a glass batch containing a reducing agent and a compound of copper, forming the glass into an article, exposing at least a portion of the article to short wave radiations and thereafter heating it for a time and at a temperature sufficient to color the exposed portion red. Another object of this invention is the method of making a glass article, which comprises interposing between a source of short wave radiation and a reduced glass containing copper and tin, a body having regions, which are opaque to the radiations and regions, which are substantially transparent to the radiations, irradiating the glass through the body with the radiations and subsequently heat treating the glass to develop a ruby colored image therein.
U.S. Pat. No. 2,422,472 to Dalton discloses a method creating an article comprising a substantially colorless reduced glass containing an irradiated reduction product of CuO and having within its mass a predetermined, latent, photographic image capable of being developed as a permanent red coloration in a colorless glass body by uniformly hearing the entire glass body.
The Russian invention No. 321422 to Agadjanov et. al. discloses a method of manufacturing decorative products inside a transparent material by changing the material structure by laser radiation. As disclosed, by moving a material relative to a focused laser beam, it is possible to create a drawing inside the material.
U.S. Pat. No. 3,715,734 to Fajans discloses a three-dimensional memory storage unit, which is prepared by carbonizing selected spots in a block of polymethylmethacrylate by means of a steeply converging laser beam. The energy of the beam is applied in pulses of such duration and at such intensity that carbonization takes place only at the focal point of the beam.
U.S. Pat. No. 4,092,518 to Merard discloses a method for decorating transparent plastic articles. This technique is carried out by directing a pulsed laser beam into the body of an article by successively focusing the laser beam in different regions within the body of the article. The pulse energy and duration is selected based upon the desired extent of the resulting decorative pattern. The effect of the laser is a number of three dimensional “macro-destruction” (fissures in the material of the article) appearing as fanned-out cracks. The pattern of the cracks produced in the article is controlled by changing the depth of the laser beam focus along the length of the article. Preferably, the article is in the form of a cylinder, and the cracks are shaped predominantly as saucer-like formations of different size arranged randomly around the focal point of the optical system guiding a laser beam. The device used to carry out this technique is preferably a multi-mode solid-state, free-running pulse laser used in conjunction with a convergent lens having a focal length from 100 to 200 mm.
GDR Pat. No. 237 972 A3 to Wiederhold et al. discloses an opaque image pattern imbedded within the inner volume of an otherwise transparent article, without surface damage, using a focused, guided laser with an intensity (power density) at the focal area that exceeds the damage threshold. For instance, to create internal marks in a material having a damage intensity threshold of 40 kW/mm
2
which is achievable with an average peak power of 20 kW, a laser with a 2,5 time higher peak power (50 kW) is employed, implying conditions under which ionization is reached.
U.S. Pat. No. 4,467,172 to Ehrenwald et al. discoses the method and apparatus g for laser engraving diamonds with permanent identification markings. A shallow penetration depth and narrow line width is achieved by using a harmonic conversion device to produce an output frequency which is second harmonic of the fundamental laser frequency in combination with a lens system having a short focal length to provide a high density pinpoint spot of laser energy.
U.S. Pat. No. 4,744,647 to Meshel et al. describes semi-opaque cornel contact lens and method of formation. A selected pattern of disruptions in the lens material of a soft or hard corneal contact lens is provided which substantially disrupts the undistorted transmisability of an image to the lens to render it semi-opaque. Preferably, these disruptions are formed by a laser beam, which cause the disruptions. The pattern may be used for coding of lens prescription or the like.
The Japan invention No. 61-288928 to Shigeru Hirukawa disclose the laser beam processing device, which permits partial and satisfactory removal of a resist film on a prescribed substrate or the like by condensing laser light of a CW laser, scanning said light on an object and processing the object while monitoring the processing condition of the object.
U.S. Pat. No. 4,843,207 to Urbanek et al., discloses a method of creating controlled decorations on the surface of a hollow symmetrical transparent article. This technique is preferably carried out on glass. The glass is preconditioned with a coating on the outer surface of the glass being approximately 1.2 mm thick and made of a material having at least 75% absorption of laser radiation. The technique is also carried out using a laser having a wave of length of 0.5 to 2 microns acting upon the external coating through the wall of the cylindrical glass article. The laser beam moves so that it is focused on the surface of the cylinder, and moves about the axis of symmetry of the cylinder to irradiate the aforementioned surface coating. As a result, the irradiated portions of the surface coating go through a phase change and a pattern is formed.
U.S. Pat. No. 5,206,496 to Clement et al. discloses a method and apparatus for providing in a transparent material, such as glass or plastic, a mark which is visible to the naked eye or which may be “seen” by optical instruments operating at an appropriate wavelength. The Clement et al. Patent describes a method and apparatus for producing a subsurface marking which is produced in a body such as bottle, by directing into the body a high energy density beam and bringing the beam to focus at a location spaced from the surface, so as to cause localized ionization of the material. In the preferred embodiment the apparatus includes a laser as the high energy density beam source. The laser may be a Nd-YAG laser that emits a pulsed beam of laser radiation with a wavelength of 1064 nm. The pulsed beam is incident upon a first mirror that directs the beam through a beam expander and a beam combiner to a second mirror. A second source of laser radiation in the form of a low power He-Ne laser emits a secondary beam of visible laser radiation with a wavelength of 638 m. The secondary beam impinges upon the beam combiner where it is reflected toward the second reflecting surface coincident with the pulsed beam of laser radiation from the Nd-YAG laser. The combined coincident beams are reflected at the reflecting surface via reflecting two other surfaces to a pair of movable mirrors for controlling movement of the beam. The beam then passes through a lens assembly into the body to be marked.
The Japan invention No 02-183681 discloses the marking method for improving the manufacturing yield of a semiconductor device by making the inner part of a transparent base plate selectively opaque and making it as the laser beam irradiates the inner part of the transparent base plate so that the focus is taken on it.
The Japan invention No. 03-120252 to Koji Kuwabara, et al. discloses the marking device and marking method.
Elve M. Alexandra
Johnson Jonathan
Troitski Igor
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