Abstract: The invention relates to a thin optical security element comprising a reflective or refractive light-redirecting surface having a relief pattern operable to redirect incident light from a light source and form a projected image on a projection surface, the projected image comprising a caustic pattern reproducing a reference pattern that is easily visually recognizable by a person. The invention also relates to a method for designing a relief pattern of a light-redirecting surface of a thin optical security element.

Abstract: The invention relates to a thin optical security element comprising a reflective or refractive light-redirecting surface having a relief pattern operable to redirect incident light from a light source and form a projected image on a projection surface, the optical parameters of this optical security element fulfilling a specific projection criterion such that the projected image comprises a caustic pattern reproducing a reference pattern that is easily visually recognizable by a person. The invention also relates to a method for designing a relief pattern of an optical security element.

Abstract: The invention relates to a thin optical security element comprising a reflective or refractive light-redirecting surface having a relief pattern operable to redirect incident light from a light source and form a projected image on a projection surface, the projected image comprising a caustic pattern reproducing a reference pattern that is easily visually recognizable by a person. The invention also relates to a method for designing a relief pattern of a light-redirecting surface of a thin optical security element.

Abstract: The invention relates to a thin optical security element comprising a reflective or refractive light-redirecting surface having a relief pattern operable to redirect incident light from a light source and form a projected image on a projection surface, the optical parameters of this optical security element fulfilling a specific projection criterion such that the projected image comprises a caustic pattern reproducing a reference pattern that is easily visually recognizable by a person. The invention also relates to a method for designing a relief pattern of an optical security element.

Abstract: The present invention is related to the filed of optically variable security elements comprising a region based on a single cured ink comprising a cholesteric liquid crystal polymer, said region having at least two, preferably at least three, patterns exhibiting, at at least one viewing angle, a different CIE (1976) color index parameter and/or a different position of the selective reflection band for protecting security documents against counterfeiting and/or illegal reproduction.

Abstract: A heat exchanger for exchanging heat between two fluids, use of the exchanger with liquid metal and gas, and application to a fast neutron nuclear reactor cooled with liquid metal. The present invention concerns a heat exchanger (1) for exchanging heat between a first fluid (N2) and a second fluid (Na). According to the invention, the structure of the heat exchanger makes it possible to supply and recover the primary fluid, such as sodium (Na), to and from a given longitudinal end (2a) opposite the longitudinal end (2b) by which the secondary fluid, such as nitrogen (N2), is supplied and recovered. This allows a physical separation between the paths of the two fluids in the exchanger, with the possibility, in particular, of having restricted access for one of the fluids, such as sodium (Na) and non-restricted access for the other of the fluids, such as nitrogen (N2).

Abstract: A process for manufacturing a security feature having a tactile pattern, said method including applying on a substrate a radiation-curable basecoat composition by a process selected from inkjet, offset, screen printing, flexo printing and rotogravure; at least partially or fully radiation-curing the radiation-curable basecoat composition so as to obtain a radiation-cured basecoat; applying on the radiation-cured basecoat a radiation-curable topcoat composition in a form of indicia by a process of screen printing, flexo printing or rotogravure; radiation-curing said radiation-curable topcoat composition so as to form a radiation-cured topcoat. The radiation-curable basecoat composition and/or the radiation-curable topcoat composition includes one or more machine readable feature substances independently selected from cholesteric liquid crystal pigments, luminescent compounds, infrared-absorbing compounds, magnetic compounds and mixtures thereof.

Abstract: The present invention is related to the filed of optically variable security elements comprising a region based on a single cured ink comprising a cholesteric liquid crystal polymer, said region having at least two, preferably at least three, patterns exhibiting, at at least one viewing angle, a different CIE (1976) color index parameter and/or a different position of the selective reflection band for protecting security documents against counterfeiting and/or illegal reproduction.

Abstract: A heat exchanger for exchanging heat between two fluids, use of the exchanger with liquid metal and gas, and application to a fast neutron nuclear reactor cooled with liquid metal. The present invention concerns a heat exchanger (1) for exchanging heat between a first fluid (N2) and a second fluid (Na). According to the invention, the structure of the heat exchanger makes it possible to supply and recover the primary fluid, such as sodium (Na), to and from a given longitudinal end (2a) opposite the longitudinal end (2b) by which the secondary fluid, such as nitrogen (N2), is supplied and recovered. This allows a physical separation between the paths of the two fluids in the exchanger, with the possibility, in particular, of having restricted access for one of the fluids, such as sodium (Na) and non-restricted access for the other of the fluids, such as nitrogen (N2).

Abstract: The present invention is related to a process for manufacturing a security feature comprising a tactile pattern, said method comprising the steps of applying on a substrate a radiation-curable basecoat composition by a process selected from the group consisting of inkjet, offset, screen printing, flexo printing and rotogravure; at least partially or fully radiation-curing said radiation-curable basecoat composition so as to obtain a radiation-cured basecoat; applying on the radiation-cured basecoat obtained under step ii) a radiation-curable topcoat composition in a form of indicia by a process selected from the group consisting of screen printing, flexo printing and rotogravure; radiation-curing said radiation-curable topcoat composition so as to form a radiation-cured topcoat, wherein the radiation-curable basecoat composition and/or the radiation-curable topcoat composition comprises one or more machine readable feature substances independently selected from the group consisting of cholesteric liquid cryst

Abstract: An electronic circuit includes a substrate. A capacitor and at least one semiconductor component are supported by a surface of the substrate. A substantially planar screen, oriented parallel to the surface of the substrate and made of metallic material, is placed between the capacitor and the semiconductor component. Preferably, the semiconductor component is placed in proximity to the surface of the substrate and several superposed layers of insulating material cover the surface of the substrate and the semiconductor component. The capacitor is then placed within at least one layer of insulating material above the semiconductor component, and the screen is placed within an intermediate layer of insulating material between the layer incorporating the capacitor and the surface of the substrate.

Abstract: A ramp generator is provided that includes an amplifier, first and second transistors, a variable resistive load having a control electrode, and a capacitor. The amplifier has an inverting input that receives a first reference voltage, and an output connected to the gate of the first transistor. The first transistor has a source connected to a second reference voltage, and a drain connected to the non-inverting input of the amplifier and also to the variable resistive load. The second transistor mirrors the current of the first transistor so as to charge the capacitor, which is periodically discharged by a discharging circuit. In one embodiment, the generator further comprises a comparator, a filter, and an integrator that control the variable resistive load so as to generate a slope having characteristics that are noticeably independent from dispersion, from manufacturing methods, and temperature.

Abstract: A voltage ramp generator includes a capacitance and a charging circuit that permits generation of a charging current for the capacitance. The charging circuit for the capacitance includes a current generator having a resistance Rg2. The charging circuit for the capacitance includes components, such as resistance Re, that enables the capacitance charging current to be proportional to (Re/Rg2)2. The voltage ramp generator is applicable to circuits for DC voltage converters operating in a current mode.

Abstract: An electronic circuit comprises a substrate (100), a capacitor (11) and at least one semiconductor component (10) which are supported by a surface (S) of the substrate. A substantially plane screen (12), parallel to the surface of the substrate and made of metallic material, is furthermore placed between the capacitor and the semiconductor component. Preferably, the semiconductor component is placed in proximity to the surface (S) of the substrate and several superposed layers (1-6) of insulating material cover the surface of the substrate and the semiconductor component. The capacitor is then placed within at least one layer (5) of insulating material above the semiconductor component, and the screen (12) is placed within an intermediate layer (4) of insulating material between the layer incorporating the capacitor and the surface (S) of the substrate.

Abstract: A ramp generator is provided that includes an amplifier, first and second transistors, a variable resistive load having a control electrode, and a capacitor. The amplifier has an inverting input that receives a first reference voltage, and an output connected to the gate of the first transistor. The first transistor has a source connected to a second reference voltage, and a drain connected to the non-inverting input of the amplifier and also to the variable resistive load. The second transistor mirrors the current of the first transistor so as to charge the capacitor, which is periodically discharged by a discharging circuit. In one embodiment, the generator further comprises a comparator, a filter, and an integrator that control the variable resistive load so as to generate a slope having characteristics that are noticeably independent from dispersion, from manufacturing methods, and temperature.

Abstract: An integrated circuit including an output pad, an output block coupled to the output pad via a capacitor, a first one-way conduction element for connecting the pad to a supply line when the voltage on the pad exceeds the voltage of the supply line by a first threshold voltage, a second one-way conduction element for connecting the pad to the circuit ground when the voltage on the pad is smaller than the ground voltage by a second threshold voltage, a resistor coupled on the one hand to the output pad and on the other hand to the supply line via a switch which is turned off when the circuit is idle and which is turned on when the circuit is in a normal operating mode.

Abstract: A voltage ramp generator includes a capacitance and a charging circuit that permits generation of a charging current for the capacitance. The charging circuit for the capacitance includes a current generator having a resistance Rg2. The charging circuit for the capacitance includes components, such as resistance Re, that enables the capacitance charging current to be proportional to (Re/Rg2)2. The voltage ramp generator is applicable to circuits for DC voltage converters operating in a current mode.

Abstract: An integrated circuit including an output pad, an output block coupled to the output pad via a capacitor, a first one-way conduction element for connecting the pad to a supply line when the voltage on the pad exceeds the voltage of the supply line by a first threshold voltage, a second one-way conduction element for connecting the pad to the circuit ground when the voltage on the pad is smaller than the ground voltage by a second threshold voltage, a resistor coupled on the one hand to the output pad and on the other hand to the supply line via a switch which is turned off when the circuit is idle and which is turned on when the circuit is in a normal operating mode.

Abstract: The device for the comparison of the levels of two input signals MI, PI includes a first comparator COMP1, the switching of the comparator being expressed by a change-over of the output OUT1 of the comparator from a first logic state into a second logic state, the change-over of the output OUT1 from one logic state “0” into the other state “1” being faster than the change-over in the other direction. The device also includes a second comparator COMP2 with an identical structure, to whose input the signals to be compared are applied invertedly so that the switching operations in the comparators are inverted. The output of each comparator is applied to an associated logic circuit 1, 2 capable of accelerating the inverse switching in the other comparator for a change in the output corresponding to the fastest change-over.

Abstract: A device for comparing two input signals includes a first comparator with differential outputs to whose inputs the signals are applied. The first comparator is followed by a second comparator delivering an output logic signal of the device. Each comparator includes at least one input differential stage, and each stage has two arms biased by a bias current generator. The comparison device may also include at least one additional current supply circuit associated with an arm of the input differential stage of the first comparator to copy the current of the arm and add it, with a multiplier factor, to the bias current of the input differential stage of the second comparator. This facilitates a corresponding switch-over.