Technical field of the invention

The present invention refers to a system and a method for coloring, particularly for anodically coloring, metal objects.

Prior art

A technique for coloring metals called anodic coloring is known. Such technique, which can be applied for coloring surfaces of objects made of materials on which a patina can be formed (such as titanium, niobium, tantalum), uses the so- called electrochemical oxidation, by which an electrochemical cell is made comprising an anode (corresponding to the metal to be colored by oxidation), a cathode (generally a noble metal) and an aqueous electrolyte, whose conductivity can be increased by selecting an acid pH or alkaline pH or by dissolving a salt into the same. Connecting the cathode and anode to an electric power generator makes possible to control the potential of the electrochemical cell, on which the thickness and color of a metal oxide film forming on the anode are dependent. Therefore, the potential of the electrochemical cell is commanded as a function of the color to be obtained on the metal surface.

Known processes for anodically coloring metals are for example disclosed in documents US 5,160,599, EP 1 199 385 A2, EP 0 413 589 A1 .

Brief summary of the invention

The object of the present invention consists of making available a system and a method for anodically coloring metal objects, alternative to the ones of the known art, by which a coloring tailored to a specific user cab ne obtained, for example coloring a jewel (such as a wedding ring) reflecting the mood of a user in a particular period of time.

These and other objects are met by a system for coloring metal objects according to claim 1 and by a method of coloring metal objects according to claim 10.

The dependent claims define possible advantageous embodiments of the invention.

Brief description of the figures

In order to obtain a better comprehension and appreciate the advantages, some embodiments thereof will be described in the following in an exemplifying and non-limiting way with reference to the attached figures, wherein: Figure 1 is a block diagram of a system for coloring metal objects according to a possible embodiment;

Figures from 2 to 14 show possible relationships between a biometric signal B and a coloring command signal C in the coloring system according to the invention:

Figure 15 shows a possible relationship between the values of the coloring command signal C and the coloring of portions of a metal objects colored by a system according to the invention.

Detailed description of the invention

The present disclosure, according to at least one of the above-mentioned aspects, can be implemented according to one of more of the following embodiments, optionally combined with each other.

For the purposes of the present description and of the attached claims, the term “one” must be understood as one or at least one, and the singular comprises also the plural, unless the context clearly indicates otherwise.

With reference to the attached Figure 1 , a system for coloring, particularly for anodically coloring, metal objects, is indicated by reference 1 . The colorable metal objects can be of any type and have any dimensions. The metals colorable by the system according to the present invention include for example titanium, aluminum, zirconium, tungsten, tantalum, magnesium, niobium, and alloys thereof, or any other metal material capable to be passivated and to form an oxide layer such to obtain an interference coloring.

The system 1 comprises a device 2 for anodically coloring metal objects. According to what is cited in the introductory part of the present description, the device 2 comprises an electrochemical cell 3 having a cathode (preferably an inert metal, called counter electrode) and wherein the anode (called working electrode) is made by the object on which the anodic coloring is made, or by a portion thereof. The electrochemical cell 3 is further provided with an aqueous electrolyte, whose conductivity can be increased by selecting an acidic pH or alkaline pH, or by dissolving a salt into the same. According to an embodiment, the aqueous electrolyte is contained inside a porous material placed in direct contact with the metal material, as for example a sponge or another porous ceramic material, having the function of localizing the electrochemical process in a determined surface zone of the anode subjected to the coloring. Moreover, the device 2 comprises an electric power gen- erator 4 connectable to the cathode and anode, suitable to generate a potential difference V between the electrodes of the electrochemical cell 3, so that a surface of the anode is covered by a metal oxide film, obtained by oxidizing the anodic material, which is responsible for the color which someone wants to obtain.

The electric power generator 4 generates the above-mentioned potential difference V based on a coloring command signal C, which is obtained as will be described in the following. Such coloring command signal C can be a signal, particularly a current signal, which is continuous (the so-called continuous current anodizing), pulsed (if the voltage or current is pulsed without inverting the polarities of the electrodes) or alternating (the so-called alternating current anodizing, if the voltage or current is changed by inverting the polarization between the working electrode and counter electrode).

The electric power generator 4 can comprise a potentiostat or a galvanostat. In other words, the controlling of the electrodes of the electrochemical cell 3 can be performed by a voltage-control (the so-called potentiostatic anodizing) or by a current-control (the so-called galvanostatic anodizing). Preferably, the electric power generator 4 controls the potential difference V between the electrodes by a voltagecontrol because the thickness of the obtained oxide film, and consequently the coloring of the metal surface, are correlated to the voltage.

Moreover, the system 1 comprises a device 5 for measuring a biometric parameter of a living being, particularly a human being or an animal, apt to generate a signal B representative of such biometric parameter.

In an embodiment, the signal representative of a biometric parametric parameter comprises a signal representative of a cardiac parameter, which can for example comprise:

- a heart rate signal, in other words the number of cardiac impulses detected in a predefined time interval (e.g., the number of heart beats, bpm);

- an electric signal related to the repeated depolarizations and repolarizations of the cardiac muscle, commonly used for obtaining and electrocardiogram (ECG);

- a signal related to the movements of the rib cage caused by the systolic and diastolic movements of the heart, commonly used for obtaining an apex cardiogram (ACG);

- a signal related to pressure variations in a blood vessel, commonly used for obtaining a cardiac sphygmogram, such as a carotidarteriogram; - a signal related to the heart sounds, in other words the cardiac vibrations generated by the heart during the cardiac activity determined by the acceleration and deceleration of blood, which is transmitted to the thoracic walls;

- a signal related to the ballistic forces caused by the cardiac contractions and by the blood flow through the great vessels;

- a signal related to the volume variations of the heart or of the apparatuses connected to it.

According to an embodiment, the biometric signal B can be a combination of several signals, for example two or more of the above-cited signals.

Depending on the biometric signal B to be detected, the device 5 can for example comprise one or more of the following devices:

- an electrocardiograph (ECG)

- a cardiac plethysmograph (PPG)

- a ballistocardiograph (BCG)

- a phonocardiograph

- an echocardiograph

- an echo Doppler

- a seismocardiograph (SCG)

- a gyrocardiograph (GCG)

- an apex cardiograph (ACG)

- an impedance plethysmograph.

According to an embodiment, the signal representative of a biometric parameter B comprises a signal representative of a brain parameter, which can for example comprise one or more of the following signals or a combination thereof:

- an electric signal generated by the encephalon such as a, or p, or y, or 5, or p, or 9 waves or a combination thereof. Such signals are commonly used for producing an electroencephalogram (EEG). In this case, the device 5 can comprise an electroencephalograph;

- a neuronal signal responsive to an optical stimulus, commonly used for producing an optoencephalogram (OEG). In this case, the device 5 can comprise an opto-electroencephalograph.

In an embodiment, the signal representative of a biometric parameter B comprises a combination of one or more signals representative of a cardiac parameter and of one or more signals representative of a brain parameter. Moreover, the system 1 comprises a control unit 6 operatively connected or connectable to the anodic coloring device 2 and to the biometric parameter 5 measuring device, configured to receive at the input the biometric signal B and to provide at the output the coloring command signal C, determined based on the trend of the biometric signal B. The control unit 6 can be part of the anodic coloring device 2 or of the biometric parameter measuring device 5, or can be separated from them. For example, the control unit 6 can be part of an independent control device (such as a PC, a tablet, a smartphone, on which a suitable software is loaded and executed), connected or connectable on site, by wire or wirelessly, to the devices 2 and 5, or can be a remote device connected to the devices 2 and 5 for example by a data network.

The relationship between the coloring command signal C and the biometric signal B can vary based on the type of the anodic coloring device 2 and the biometric parameter measuring device 5. Particularly, depending on the type of the electric power generator 4 (a potentiostat or a galvanostat), the coloring command signal C can be a voltage or current signal. Depending on the input biometric signal B, such coloring command signal C can completely coincide with the biometric signal or can be pre-processed (for example by filtering for reducing a possible noise, or by numerical reprocessing for improving its resolution). Preferably, the coloring command signal C has the same trend of the possibly pre-processed biometric signal B.

Figures from 2 to 14 show examples of possible time relationships t (for example expressed in seconds s) between the biometric signal B (on the left in the figures, expressed in many ways) and the coloring command signal C (on the right in the figures, which can be expressed by voltage or current, according to what was hereinbefore said: for example, it can be the voltage or current signal apt to generate the potential difference V between the electrodes of the electrochemical cell 3). Particularly:

- Figure 2 is an example of a conversion of an electrocardiogram (ECG), measured in millivolts (mV), into a voltage or current signal;

- Figure 3 is an example of a conversion of an impedance cardiograph (ICG), measured in ohm/s, into a voltage or current signal;

- Figure 4 is an example of a conversion of a phonocardiogram (PCG), measured in mV, into a voltage or current signal; - Figure 5 is an example of a conversion of an echocardiogram (ECO), measured in cm/s, into a voltage or current signal;

- Figure 6 is an example of a conversion of a ballistocardiogram (BCG), measured in Newton (N), into a voltage or current signal;

- Figure 7 is an example of a conversion of a gyrocardiogram (GCG), measured in 7s, into a voltage or current signal;

- Figure 8 is an example of a conversion of a seismocardiogram (SCG), expressed as an acceleration measured in mg, into a voltage or current signal;

- Figure 9 is an example of a conversion of a diagram of the blood pressure, expressed in millimeters of mercury (mmHg), into a voltage or current signal;

- Figure 10 is an example of a conversion of an apex cardiogram (ACG), measured in millimeters (mm), into a voltage or current signal;

- Figure 1 1 is an example of a conversion of a photoplethysmogram (PPG), measured in decibel (dB), into a voltage or current signal;

- Figure 12 is an example of a conversion of the time trend of the cardiac frequency, expressed in bpm, into a voltage or current signal;

- Figure 13 is an example of a conversion of the time trend of an electroencephalogram (EEG), expressed in mV, into a voltage or current signal;

- Figure 14 is an example of a conversion of the time trend of an optoencephalogram (OEG) to a voltage or current signal.

From the above given examples, it is understood that the time trend of the coloring command signal C is preferably the same or is similar to the trend of the biometric signal, except for the unit of measure.

Ultimately, the system 1 according to the present invention enables to transform the biometric signals (having a varying trend) into colors of the metal object, since to each value or value ranges of the biometric signal different values of the coloring command signal C correspond, particularly of the potential difference V between the electrodes of the electrochemical cell 3, which is the magnitude on which the coloring of the surface of the metal object depends, according to what is schematically shown in Figure 15. The so determined different colors can be distributed on the surface of the metal object according to many possible criteria: for example, a random criterium, or according to a predefined pattern.

To this regard, it is for example possible to move the counter electrode, in other words the cathode, by suitable movement means in order to color the anode by predefined patterns.

It is observed that the conversion between the biometric signal B and the coloring command signal C can performed in real time or in different times. For example, it is possible to store the biometric signal B (for example in an optional memory module 7 of the control unit 6) and afterwards to convert it into the coloring command signal C. In this manner it is for example possible to detect, by the biometric signal B, feelings of a person in a specific moment (for example during his/her wedding) and then to transfer them on a metal object, for example on a wedding ring or on a picture, so that its coloring will mirror the feelings during the wedding.

According to a further aspect of the present invention, a method of coloring metal objects comprises the steps of:

- measuring a biometric parameter of a living being and generating a biometric signal B representative of the same. Such step can be for example performed by the biometric parameter 5 measuring device;

- determining a coloring command signal C in dependence of the biometric signal B. Such step can be for example performed by the control unit 6;

- coloring by an anodic coloring a surface of a metal object based on the coloring command signal C. Such step can be for example performed by the anodic coloring device 2.

In an embodiment, the step of coloring by the anodic coloring a surface of a metal object comprises the steps of:

- making by the metal object or by a portion thereof an anode of an electrochemical cell 3 comprising a cathode, for example of the electrochemical cell 3 having the beforehand described characteristics;

- generating a potential difference V between the cathode and the anode in dependence of said coloring command signal C. Such step can be for example performed by the power generator 4.

According to an embodiment, the method further comprises a step of moving the cathode for coloring according to predefined patterns of the anode.

The biometric signal B comprises a signal representative of a cardiac parameter and/or a signal representative of a brain parameter of the living being, which preferably comprise one or more of the examples of the signals/parameters beforehand listed with reference to the system 1 .

In an embodiment, the method further comprises a step of storing the biometric signal B, for example in the memory module 7 of the control unit 6. The coloring command signal C is determined as a function of the stored biometric signal, after the step of storing the same.

It is observed that, in the present description and in the attached claims, the control unit and also the elements indicated by the expression “module”, can be implemented by hardware devices (for example central units), by software or by a combination of hardware and software.

A person skilled in the art, in order to meet specific contingent needs, could introduce many additions, modifications, or substitutions of elements with other operatively equivalent ones to the described embodiments of the system and method for coloring metal objects, without falling out of the scope of the attached claims.