Form the method for Optical Variable Imaging and the product that this method is made in the metal surface
Technical field
The present invention relates to form the technology of Optical Variable Imaging (OVD, Optically Variable Device), the metal coin and the metal chapter that particularly utilize metal cold forming process method on the metal surface, to form the method for Optical Variable Imaging and utilize this method to make.
Background technology
Optical Variable Imaging comprises the image that all kinds of hologram images, dot matrix image, e-beam (electron beam) image, various coded image and the similar techniques of white light and laser reconstruction form etc., has been widely applied to every field, particularly false proof field.Existing OVD copying image technology is normally made the OVD image metal die (being also referred to as the OVD working version), utilizes made metal die to extrude the OVD image by the mode of mold pressing at plastics or similar material patrix; Perhaps at first form one deck coating, copy the OVD image by roll extrusion OVD working version then at the material surface that will form the OVD image.In the process of above-mentioned punching press or roll extrusion, adopt the mode of heating and pressurizing that the OVD image is fixed on plastics or the coating.
Yet existing OVD copying image technology is not suitable for formation OVD image on the metal surface.This is because carry out mold pressing or roll extrusion makes metal material generation oxidation easily by type of heating, in a single day the metal surface has generated oxide layer, the fineness of not only formed OVD image can not get guaranteeing, and caducous oxide layer can be destroyed formed OVD image.Particularly when people wish on metal coin and metal chapter to form the OVD image with the antiforge function that strengthens metal coin and metal chapter or art value, based on the frequent circulation of people to currency, the requirement of aspects such as long-term usability and permanent keeping quality, existing OVD image transfer technique can not satisfy people's requirement far away.The above-mentioned deficiency of prior art has been limited to the expansion of OVD image technique application.
United States Patent (USP) 6,017,657 disclose a kind of scheme of utilizing rolling cold forming method to form the holographic relief pattern in the metal surface.But this scheme generally is applicable to plate material that promptly has an even surface of mold pressing or thin coiled material, does not make the product with surface relief (referring to macroscopical embossment, is not little embossment of the nanometer scale of OVD image) that resembles metal coin, chapter and so on and be suitable for.
Content of the present invention
At the deficiencies in the prior art, the objective of the invention is to propose a kind of method that on the metal surface, forms the OVD image, the OVD imagery exploitation metal cold forming process mode that is formed on the working metal sheet is directly copied on the metal surface (no coating).The OVD image fineness height that utilizes this method to form can for good and all be kept on the metal surface and can not take off change.
Another object of the present invention is to utilize the above-mentioned method that forms the OVD image on the metal surface to make metal coin and the metal chapter that has the OVD image, made metal coin and metal chapter not only have stronger antiforge function, and clear picture is bright, dynamic effect is good, rich color, stereoscopic sensation are strong, has satisfied the requirement of people for artistic appreciation, collection and the antifalsification of metal coin and metal chapter.
For realizing above-mentioned purpose of the present invention, a kind of method that forms the OVD image on the metal surface has been proposed, may further comprise the steps:
Making has the active gage of OVD image, and described active gage thickness is 50 μ-350 μ, and hardness is in the scope of webster hardness 100-480, and is not less than the hardness of described metal surface at least; The surface that described active gage is had Optical Variable Imaging stacks together towards the metal surface, place between the upper die and lower die, by the pressure punching press of patrix with the 5-200 ton, with the OVD image transfer on the described active gage to described metal surface.
According to the present invention, described metal surface is formed by simple metal material or alloy material.
According to a preferred embodiment of the invention, adopt electrocasting to form the nickel active gage that has the OVD image.Thickness the best of nickel active gage is 150 μ-170 μ, and webster hardness is 200.In this technical scheme, the optimum pressure of punching press is 50 tons.
For realizing above-mentioned purpose of the present invention, the invention provides a kind of metal coin of the OVD of having image, it is characterized in that the OVD image that forms at the useful above-mentioned process for stamping of at least one mask of metal coin.
For realizing above-mentioned purpose of the present invention, the invention provides a kind of metal chapter of the OVD of having image, it is characterized in that the OVD image that forms at the useful above-mentioned process for stamping of at least one mask of metal chapter.
Brief description of drawings
The employed mould of the schematically illustrated method of the present invention of Fig. 1;
Fig. 2 shows working metal sheet that the method according to this invention will have the OVD image and is placed on desire and forms thereon on the metal surface of OVD image;
Fig. 3 show utilize punching press mode with the OVD image transfer to the metal surface;
Fig. 4 shows according to the specific embodiment of the present invention, forms the OVD image on the metal surface.
Embodiment
According to the present invention, at first to prepare the working metal sheet that has the OVD image.The hardness of metal materials of active gage should greater than or equal to desire to form the hardness of the metal surface of OVD image at least thereon.Groove fineness, the degree of depth and the shape of OVD image will meet the requirement that desire forms the metal surface of described OVD image thereon on the active gage.
According to a preferred embodiment of the invention, adopt the nickel active gage.The webster hardness of nickel active gage is chosen as 100-480, and preferred webster hardness is 200.The hardness of active gage material is too little, and for example less than webster hardness 100, the OVD image that is formed by concavo-convex grating in punching course subsequently easily deforms, and the recycling rate of waterused of active gage is low.The hardness of active gage material is too big, and for example greater than webster hardness 480, active gage will embrittlement, can't realize transfer printing in batches, and the OVD image transfer is imperfect.
The present invention can adopt that various known methods prepare the working metal sheet that has the OVD image in the prior art.According to above-mentioned preferred version of the present invention, adopt the mode of electroforming to prepare the nickel active gage that has the OVD image, yet, one of ordinary skill in the art will appreciate that the present invention is not limited thereto.Electroforming is a kind of special process method of electroplating, and the coat of metal of its formation is thicker, generally greater than 10 μ, this coating with can be separated fully by the plating interface with as the working metal sheet.
After the nickel active gage that has the OVD image forms, the metal surface base material (through polishing or pressing) of desiring to form the OVD image thereon is placed in the mould shown in Figure 1.Label 1 and 2 represents to be used for the upper die and lower die of punching press OVD image on the metal surface respectively among Fig. 1, and the counterdie upper end is provided with at least one groove that is used for place work piece, and metal surface base material 3 is placed in the groove.
The nickel working metal sheet 4 of the above-mentioned OVD of having image is fastened on the base material of metal surface, as shown in Figure 2.The one side that has image is towards the metal surface, and design forms the position of OVD image on the OVD image alignment metal surface on the nickel active gage.Then, patrix is descended, as shown in Figure 3, the nickel active gage is pressed to the metal surface tightly.Since the hardness of active gage greater than or equal the hardness of metal surface material at least, be applied under the enough big situation of the pressure of patrix, the OVD image can be transferred on the metal surface from the nickel active gage.
According to above-mentioned preferred embodiment of the present invention, the thickness of nickel active gage is generally 50 μ-350 μ, is preferably 120 μ-170 μ.The thickness of active gage is too little, and for example less than 50 μ, then the insufficient strength of active gage easily deforms in punching course subsequently.When the thickness of active gage is too big, for example greater than 350 μ,, cause the active gage expansion of metal owing in punching course subsequently, need to impose severe pressure, the OVD image is destroyed.Therefore, active gage thickness is too big or too little, will cause descend greatly the serviceable life of active gage.According to the thickness and the hardness of nickel active gage, the pressure size when selecting punching press is generally the 5-200 ton, is preferably 50 tons.OVD image in above-mentioned pressure limit on the active gage can be transferred on the metal surface.If pressure is too little, the OVD that transfers to the metal surface is image blurring unclear; Pressure is too big, and active gage is deformed.The time of exerting pressure is generally 3-6 second.
After the transfer of OVD image is finished in punching press, remove patrix and take out the nickel active gage, obtain having the metal surface base material of OVD image.Fig. 4 shows this step.
Another embodiment of the invention shows metal coin and the metal chapter that utilizes method for preparing.At first, should select the material of active gage according to the material of metal coin and metal chapter, with the hardness that guarantees active gage greater than or equal the hardness of metal coin and metal chapter at least.If the metal coin is a silver coin, the hardness of active gage is chosen as webster hardness 100-480, is preferably webster hardness 200.The thickness of active gage is 50 μ-350 μ, and optimum thickness is 150 μ-170 μ.Pressure during punching press is the 5-200 ton, and optimum pressure is 50 tons, and the punching press time is 3-6 second.Under above-mentioned process conditions, can prepare the metal coin and the metal chapter that have the OVD image, the fineness of OVD image (referring to the groove width by the OVD image of concavo-convex optical grating constitution) is 0.5 μ-2.5 μ, OVD image gash depth is 0.03 μ-0.8 μ, groove shape is rectangle, sinusoidal, serrate, or other analogous shape, and the various combinations of these shapes.The collection of metal coin and metal chapter and the requirement of artistic appreciation have been satisfied.The OVD image can be formed on the one side of metal coin and metal chapter, or two-sided formation.
According to the present invention, can use same active gage compacting OVD image on the base material of a plurality of metal surfaces repeatedly.This feature extremely helps wanting the product of a large amount of duplications of production, for example metal coin and metal chapter, metal handicraft, metal jewelry etc.
According to the present invention, except that nickel, the material of active gage can also be other metals such as copper, steel.Described metal surface is that simple metal material or alloy material form, and for example can be simple metal and alloys thereof such as gold, silver, copper, platinum, palladium, aluminium, nickel, and other outside surface is the material of above-mentioned metal.