Abstract: A display has a panel (3) connected to a funnel (5). An electron gun assembly (13) positioned in a neck (4) at a narrow end of the funnel is provided for directing electron beams toward a screen (12) on the panel. The display includes a yoke (14) to scan the beams across the screen, a degauss coil positioned on the funnel for degaussing the display, and a DC canceller coil (72) for counteracting beam displacement caused by North/South magnetic fields. The display can include a means to dynamically correct beam landing errors, additional coils near the wide end of the funnel to further assist in correcting beam landing errors, and a magnetic field sensor (17) to sense ambient magnetic fields and generate signal to appropriate drivers to correct for beam landing errors.

Abstract: A method of estimating the displaced size of a knot in a lumber piece includes the steps of: translating the lumber piece downstream along a flow path between a radiation source and sensor while simultaneously irradiating the lumber piece with radiation from the first radiation source whereby the radiation is attenuated by the lumber piece; collecting a set of radiation intensity data from the radiation sensor as the lumber piece is irradiated; processing the set of radiation intensity data to sum the radiation intensity data and to provide radiation intensity profiles transversely of the flow path direction and corresponding density profiles transversely of the flow path direction; mapping the density profiles to model a set of three dimensional density profiles of the lumber piece; processing the radiation intensity data to determine a clear wood density threshold value for the lumber piece and a maximum density value of the density profiles; and, computing a ratio of the summed density profile values to th

Abstract: A circuit for driving a cathode ray tube (CRT) with cathode current detection. Specifically, the present invention discloses a CRT driver circuit comprising a push-pull configuration comprising upper and lower stages of darlington paired transistors. In the lower stage, a lower prestage circuit generates a video output signal in response to a video input signal that is amplified to drive a cathode electrode of a coupled CRT. In the upper stage, an upper prestage circuit of transistors drives a voltage divider for splitting a high voltage supply between the transistors in the lower prestage circuit. In both the upper and lower stages of darlington paired transistors, upper and lower output stages of transistors are electrically active only during transient periods of the video input signal. As such, a cathode current from a static test signal can be measured from an output through the lower prestage circuit.

Abstract: In a beam current limiting circuit for a video projector, an average current is limited under closed loop control containing an anode current detection circuit 5. On the other hand, a cathode current detection circuit 107 comprises a first resistor and a second resistor in series to a cathode current circuit and detects a cutoff current at the voltage across the first resistor and an average current at the voltage across the second resistor. An offset addition circuit 11 is provided for correcting the detection value of the average current based on the maximum value of detected cathode current, and beam current is limited. Further, means 15 for detecting time change of anode current is provided and if the current value does not change for a long time, the beam current is limited to a smaller value.

Abstract: A hardware-implemented screen-saver prevents burn-in of an image displayed on a screen of a display product by automatically reducing the video gain, and therefore the contrast, of the image when the portion of the image within a two-dimensional detection window has changed by less than a predetermined amount for a predetermined period of time. A lack of change of the incoming video signal of the image is detected and used to invoke a reduction in contrast of the image displayed on the display product. This allows the image to remain visible, yet reduces the possibility of burn-in of the image in the screen of the display product.

Abstract: In a projection television system, a blue phosphor roll-off compensation network is included in the emitter circuit of a common emitter configured transistor comprising the driver amplifier for the blue cathode ray tube. The roll-off compensation network includes a voltage divider connected between the emitter of the common emitter configured transistor and a source of a bias voltage, and a second transistor having its base connected to a point within the voltage divider and its collector-emitter path connected in series with a gain changing resistor between the emitter of the common emitter configured transistor and the source of the variable bias voltage. The voltage divider determines the level of drive current at which the second transistor is rendered conductive and thereby the point at which roll-off compensation is applied. The gain changing resistor determines the amount of compensation.

Abstract: A projection television has a rear projection screen including a Fresnel lens and a lenticular lens, and a smoke sheet. The screen is characterized in that a dye or a pigment is mixed into the lenticular lens sheet or the smoke sheet which thereby has a waveform selection transmittance having the following transmittance values:.gtoreq.65% when incident light wavelength is <490 nm..ltoreq.60% when incident light wavelength is 490 nm-660 nm.wherein the transmittance, for incident light wavelength 490 nm-580 nm., is substantially different from the transmittance when the wavelength is 580 nm.-660 nm.