Abstract: A projection system incorporating a prism with dual total internal reflection function, to increase the performance of DLP™ projection, by offering a solution to combine 2 light paths to contribute to the brightness on the screen and at the same time rejecting flat-state and off-state light from entering the projection lens thereby enhancing contrast. In one implementation those two light paths can be collecting light from 2 different light sources which are driven in a pulsed manner with a duty cycle of approximately 50% for each of the two light sources at increased power. In a second implementation with a color sequential single DMD™ projector, while one light path passes a primary color the second light path passes the complementary secondary color. A special color transformation algorithm is proposed to transform the image input signals to make optimal use of the capabilities offered by the second implementation, and create maximum brightness and color saturation of the image.

Abstract: The invention relates to a pulse resistor for a frequency converter in the higher voltage and capacity range. The inventive pulse resistor is characterized by comprising at least two bipolar subsystems (24) and a resistor element (14), said subsystems (24) and said resistor element (14) being connected in series. The inventive pulse resistor is devoid of the drawbacks of known pulse resistors, it can be finely controlled by a brake current (iB) and can be adapted to any medium voltage by simple means.

Abstract: Disclosed is a high voltage inverter for converting DC power to AC power with one or more AC output phases. The inverter has for each AC output phase an AC input phase circuit comprising first and second cold cathode field emission controllable electron tubes of triode, tetrode or pentode structure. Each electron tube has a first input node for connection to a high voltage DC potential in excess of 20 KV and a second input node for connection to ground. First electron tube is serially connected between a first end of a primary winding and ground, and second electron tube is serially connected between a second end of the primary winding and ground. Control circuitry controls the electron tubes so that the first and second electron tubes alternatively conduct so as to alternately bring the first and then second end of the primary winding approximately to the potential of ground.

Abstract: The invention relates to a converter circuit comprising at least one phase module (100) having an upper and a lower converter valve (T1, . . . , T6), wherein each converter valve (TI, . . . , T6) has at least one two-pole subsystem. According to the invention, each two-pole subsystem (14) has four semiconductor switches (21, 23, 25, 27), which can be switched off and are connected electrically in series, four diodes (22, 24, 26, 28), which are each connected electrically back-to-back in parallel with one semiconductor switch (21, 23, 25, 27) which can be switched off, two unipolar storage capacitors (29, 30), which are connected electrically in series and in parallel with the series circuit comprising the semiconductor switches (21, 23, 25, 27), and an electronic system (32), whose reference potential connection (M) is electrically conductively connected to a common potential (P0).