Abstract: The front projection screen comprises firstly a support layer of substantially black color suitable for rolling onto a roll-up tube, and a weight at its bottom edge, and secondly a projection surface that is substantially white or pale gray, being smaller in size than said support layer, and being fastened to the support layer via a junction at its top edge and overlying the face of the screen that is to receive projection.

Abstract: The front projection screen comprises firstly a support layer of substantially black color suitable for rolling onto a roll-up tube, and a weight at its bottom edge, and secondly a projection surface that is substantially white or pale gray, being smaller in size than said support layer, and being fastened to the support layer via a junction at its top edge and overlying the face of the screen that is to receive projection.

Abstract: A photoelectric detector includes an electronic card connected to an emit member and a receive member, the emit member emits at least a first light signal, and the receive member receives at least a second light signal reflected from the first light signal; a cap that includes an emit lens and a receive lens made of a translucent material and positioned in front of the emit member and the receive member, respectively; and a fixing support made of an opaque material to which the card and the cap are fixed. The support has a protruding central blade that is inserted into a separating slot in the cap, between the emit lens and the receive lens.

Abstract: A photoelectric detector includes an electronic card connected to an emit member and a receive member, the emit member emits at least a first light signal, and the receive member receives at least a second light signal reflected from the first light signal; a cap that includes an emit lens and a receive lens made of a translucent material and positioned in front of the emit member and the receive member, respectively; and a fixing support made of an opaque material to which the card and the cap are fixed. The support has a protruding central blade that is inserted into a separating slot in the cap, between the emit lens and the receive lens.

Abstract: Photoreceptor circuit provided with a component, the photoreceptor surface comprising a first area able to operate in reflex mode and a second area with analog detection of position able to operate in proximity mode. The first area Z1 is a photodiode area with an output Al and the second area Z2 is a PSD type area provided with a close output A2 and a remote output A3, wherein a switch I1 connects either the A1 output in reflex mode or output A2 in proximity mode, to a processing circuit 12.

Abstract: A photoelectric cell having a receiving section fitted with an amplifier processing circuit for making the cell immune to electrical disturbances. The processing circuit uses a transfer impedance amplifier A having a gain loop 24 which is shunted by a short-circuit path 24A including a switch T1 controlled by the transmission signal E1. The switch T1 conducts when no pulses are delivered from the transmission signal E1 and does not conduct when pulses are received from the transmission signal E1.

Abstract: A photoelectric cell which detects a distance of an object, including: a first detection component configured to produce a first current which is a function of the distance of the object; a second detection component configured to produce a second current which is a function of the distance of the object; and, a processing circuit configured to shape a first voltage signal and a second voltage signal that correspond to the first current and second current, respectively.

Abstract: A proximity detector having a power switch 30 which is switched as a function of the approach of an object. The detector includes a MOS depletion transistor T1 which connects one of the terminals 15 of the detector to a control input of a power switch 30 through a control switch T2. A regulator stage 45 is coupled to T1 in order to keep T1 saturated in the closed condition of the detector and to regulate the gate voltage of T1 when the detector is in a open state.

Abstract: A proximity detector including a rapid transistor (i.e., one having a very high product gain-band) connected to a high potential voltage via a capacitor. The capacitor is connected in series to a source of a pulsed current that is a function of the proximity of an object. The capacitor is also connected to a low potential voltage via an RC circuit. The mid-point of the RC circuit is connected to the collector of a transistor connected to the high potential voltage by a collector resistor in parallel with a gain resistor of the amplifier.

Abstract: Detector comprising a sensor and a processing circuit connected to a load by means of two wires. Two switches (I1, I2) are arranged in series in a switching circuit leg (21), the ends of which (C, D) are connected to the detector terminals and the middle point (S) to a terminal (F) of the processing circuit. When operating (I1) is conductive and (I2) determines a parallel regulation of the voltage (V) at the processing circuit (12) terminals ; when in rest position, (I1) determines a series regulation of the voltage while (I2) is blocked.

Abstract: An apparatus for modulating the intensity of an X-ray beam generated by an X-ray tube. The apparatus comprises a set of at least three blades made of a material opaque to X-ray. Each blade comprises a central hub and a pair of symmetrical wings extending away from the hub. All the blades have their hubs slidably mounted on radially projecting shafts symmetrically positioned about a rotor positioned adjacent the X-ray beam and driven at variable speeds. Matching pins and threads are provided on each pair of hub and shaft to cause the corresponding blade to pivot about the shaft on which it is mounted when the speed of the rotor increases and the blades are then moved in unison radially outwardly against the action of a return spring, because of the centrifugal force. The rotor, the blades and the shafts are positioned and sized to cause the blades to intersect the X-ray beam when the rotor is driven.

Abstract: An X-ray apparatus capable of X-ray beaming in a multiplicity of directions around and through the body of a patient lying horizontally stationary on a table. The X-ray equipment is fixed to a ring which circumscribes the table and the patient. This ring is held on a support and is able to be driven into rotation, relative to the support, about its center. The apparatus also includes a fork-like suspension member which has a pair of side legs located each on one outward side of the support; the lower ends of the legs being connected with the support such as to allow the latter, and the ring it holds, to be oscillated in unison by a suitable motor mechanism about a horizontal axis joining the two lower ends of the legs; this horizontal axis being further normal to the axis of rotation of the ring. The suspension member is in turn connected to a carrier assembly provided on a top structure of the frame of the X-ray apparatus.

Abstract: A compact apparatus for moving a set of X-ray films or film cassettes past a picture-taking station. The apparatus comprises a plurality of holders impervious to X-rays onto each of which are mounted two films in back-to-back relation. The holders are moved in a closed loop past a picture-taking station where they present one of their two films for a first picture. After exposure, the holders are moved through the loop a second time during which they are rotated through 180.degree. so as to present the other films they carry at the station for a second picture.