Abstract: In a method for controlling color temperature a projection television having green, blue and red image projectors and a projection screen, holographically improving color shift performance of the screen results in an undesirable controlled input angle characteristic that attenuates images projected thereon at horizontal viewing angles of a few degrees from an axis orthogonal to the screen. Projecting blue images along an optical axis orthogonally aligned with the projection screen and projecting green and red along respective optical axes converging toward the orthogonally aligned optical axis makes it possible to energize the blue and green image projectors at substantially equal energy levels when producing a white image on the screen.

Abstract: A device and method for automatically adjusting an image condition in a display is, disclosed. The present device and method optimizes the image condition of a display according to individual preferences by taking into account the brightness and color temperature set initially by a user. Particularly, the present invention includes a photo sensor to detect the environmental illumination and a micro processor utilizing the detected data to appropriately adjust the image condition with respect to a user preference.

Abstract: A luminance correction circuit to correct areas of unevenness in luminance or color of a video image and smoothes gaps between correction blocks. The luminance correction circuit comprises a memory for storing correction data for correcting unevenness in luminance or color of video image, a timing generator for controlling read timing of the correction data from the memory, and an analog processor for processing the video signal using the correction data from the memory. A display area is divided to an appropriate number of blocks and the video signal is corrected in each block and the boundary between corrected blocks is smoothed by controlling the correction timing.

Abstract: In a single panel scrolling raster projection system of the type having a single light source, a single light valve panel, a rotatable element having surface segments for separating the white light into color bands, and field-sequential, line-at-a-time addressing means, one or more of the color bands is sized to have a height in the scrolling direction greater than the height of the panel in the scrolling direction, and sizing the remaining bands to have a scrolling height substantially equal to that of the panel. Color correction is achieved by changing the power of the light source to increase or decrease its illumination during the period in which the panel is substantially entirely illuminated by a color band having a scrolling height greater than that of the panel, and/or by adjusting the scrolling heights of the color bands relative to one another.

Abstract: Cut-off control circuits implementing DC-coupling and AC-coupling to CRT cathodes can employ the same preamplifier integrated circuits with few additional components. The preamplifier includes a switching unit for receiving control data, generating a control signal according to control data, and outputting the control signal internally or externally. The switching unit provides a control signal internally to an amplification circuit, when the preamplifier operates in a cut-off control circuit having a DC-coupling to a CRT. With a DC coupling the amplification circuit controls a DC bias applied to a CRT cathode. The switching unit provides a bus control signal externally to a bias circuit, when the preamplifier operates in a cut-off control circuit having an AC-coupling to a CRT.

Abstract: In a white balance control, correction signals are added to input chrominance signals (Uin, Vin) to obtain output chrominance signals (Uout, Vout). Chrominance sum signals are derived from the input and output chrominance signals (Uin, Vin ; Uout, Vout) and reference chrominance signals (Uref, Vref). Exponential signals are derived from the chrominance sum signals, and the reference chrominance signals (Uref, Vref) are multiplied by the exponential signals to obtain the correction signals.

Abstract: A color display with a white balance self-adjusting function, including a DC-voltage-level/gain adjusting circuit for adjusting, on the basis of adjustment data, the DC voltage level and the gain of each of R, G and B primary color signals, thereby outputting the adjusted signals. Also includes is a CRT driving circuit responsive to the output signals of the DC-voltage-level/gain adjusting circuit for outputting CRT driving signals to drive the color CRT of the display, and a cathode current detecting circuit for detecting currents flowing through the cathode electrodes of the color CRT.

Abstract: A test image 40 for determining a gamma value has a plurality of first gradation patterns 20 and a plurality of second gradation patterns 30. The patterns 20 and 30 are arranged alternately in a vertical direction. In each pattern 20, a relative brightness linearly increases from left to right. In each pattern 30, a relative brightness linearly decreases from left to right.

Abstract: An image processing apparatus comprises a coefficient generation circuit for generating a coefficient such as to decrease as a level of a luminance signal which is obtained by processing an input image signal increases while exceeding a predetermined limit value and to decrease as the luminance signal level decreases to a value lower than a predetermined lower limit value, a multiplier for multiplying a color difference signal which is obtained by processing the input image signal and the coefficient generated from the coefficient generation circuit, an integrating circuit for integrating the multiplication output from the multiplier into a plurality of predetermined regions on a screen, and a white balance control circuit to control the white balance of the screen by using the integration output of the integrating circuit.

Abstract: A method of detecting and compensating for colors displayed by a display system (10) that uses a light source (16) and a color wheel (15). A desired color balance is specified in terms of a power ratio of three primary colors. This ratio is then compared to the actual power of light filtered through each color of the color wheel. (FIGS. 2A, 2B). In a first embodiment, the filter transmission characteristics are adjusted. (FIG. 3). In a second embodiment, the size of the color wheel's segments are changed as well as the display times for data corresponding to each segment. (FIG. 4). The two embodiments can also be combined to achieve a desired color balance.

Abstract: A color picture display apparatus is provided having a driving circuit for a display device so that a low light adjustment is not influenced by a high light adjustment during white balance adjustment. Horizontal blanking period is blanked by a transistor and a clamping potential of a low light level for white balance adjustment is added to the above blanked signal. The signal, to which a clamping potential was added, is gain-adjusted and clamped by a capacitor and a transistor. Next, the clamped portion is blanked at a transistor and the blanked signal is supplied to a CRT through a driving stage. Low light adjustment is done by adjusting clamping potential with a potentiometer and high light adjustment is done by adjusting gain with another potentiometer.

Abstract: The invention is provided to automatically track the color regardless of the adjustment of the brightness level of a display device. The method provided comprises the first step of calculating a bias voltage, Rb, Gb, Bb, for the Red, Green and Blue cathode respectively, responsive to a brightness voltage applied to the control grid terminal, such that the condition of (Rb-G):(Gb-G):(Bb-G)=(Rbmin-Gmin):(Gbmin-Gmin):(Bbmin-Gmin) holds. The second step of the invention is to output the Rb, Gb, Bb obtained in the first step to each bias voltage input terminal of the video control circuit for the Red, Green and Blue cathode respectively, such that the color of the display device is independent from the change of the brightness value G.

Abstract: White balance adjustments may be carried out using the same adjustment methods as for a simultaneous system with a field-sequential display method and costs may be reduced because only one amplifier is sufficient for driving the image-receiving tube by constructing an image output circuit for use with a field-sequential display method in such a manner that the gain of a transistor set up using drive adjustment resistors and background adjustment resistors corresponding to red, green and blue is changed over by a switch on the timing of a field synchronization signal using a white balance adjustment circuit.

Abstract: An input signal is input to a detector and a synchronizing frequency of the input signal is detected by a frequency detector. Then, the number of the horizontal lines per vertical period of the input signal is determined according to the synchronizing frequency by a calculator. A control signal for defocusing an electron beam with which a blue fluorescent substance emits light is generated from a defocus controller according to the number of the horizontal lines of the input signal. Here, a range of control signals is previously stored corresponding to a range of numbers of horizontal lines. A focus signal for exactly focusing the electron beam is added to the control signal output from the defocus controller by an adder. Then, the defocus signal is output tom the adder. The defocus signal is amplified by a focus adjusting amplifier 15. The diameter of the electron beam with which the blue fluorescent substance emits the light is controlled according to the amplified defocus signal by a focus adjusting coil.

Abstract: A color temperature selector for a television receiver which can select a color temperature using electrical control signals. The emitter of a drive transistor is fixedly connected to one resistor which is connected in parallel with two selective resistors to change the emitter resistance value. The two selective resistors are selectively connected to the fixed resistor using general semiconductor switches. This arrangement allows a remote controller to select a color temperature by a control signal, and allows to select a desired combination of color temperature setting states.

Abstract: A white balance correction circuit corrects the signal level of red and blue video signals. The circuit includes both active elements and passive elements which cooperate in generating different bias resistances according to a signal level of an input color signal component. The gain of the respective transistor which ultimately amplifies and outputs each of the color signals advantageously can be varied by varying the bias of the transistor according to the signal level of the input color signal. As a result, the circuit minimizes deviation between the gamma characteristics of the red, green and blue video signals. Accordingly, a constant white balance can be maintained irrespective of the signal level of input video signals. The circuitry thus permits excellent reproduction of the original colors on the screen or tube.

Abstract: A method and circuit for correcting color errors in displaying a color video signal on the display of a color television receiver, the color television receiver having drive circuits for each of the colors red, green and blue, for forming respective color drive signals, in response to color signal components present in the color video signal, for the display, the method including setting up the color drive circuits of the color television receiver for conversion of the color signal components in the color video signal to the color drive signals to a ratio for producing a white color temperature higher than that specified in a television standard, detecting the presence and amount of color in the color video signal to be displayed on the display of the color television receiver, and reducing the color drive signals for at least two of the colors in dependence on the detected amount of color in the color video signal, whereby the resulting chromaticity of the displayed colors is the same as that when the color

Abstract: A white balance correction circuit, which receives a luminance signal (-Y) on the input terminal (20) and produces a modified luminance signal, has its gain G1 for the range of small input luminance signal level determined from the resistance ratio of resistors (29, 33), has its gain G2 for the range of medium input luminance signal level determined from the resistance ratio of the resistor 29 and resistors (33, 35) connected in parallel by a transistor (39) that has become conductive, and has its gain G3 for the range of large input luminance signal level determined from the resistance ratio of the resistor 29 and resistors (33, 34, 35) connected in parallel by the transistor (39) and a transistor (38) that has become conductive. Based on this modification, three picture projection tubes (23) have cathode voltage characteristics against the amplitude of luminance signal (-Y) represented by three polygonal lines that approximate the ideal luminance characteristics of the projection tubes.

Abstract: A white balance coefficient setting unit 51 sets a white balance coefficient for an image signal; a white balance correction coefficient determination unit 52 determines two white balance correction coefficients to be applied to a luminance signal of the image signal in accordance with the white balance coefficient; a luminance signal operation unit 59 obtains two output signals by multiplying the luminance signal by each of the two white balance correction coefficients; a first adder 57 adds one of the two output signals and a first color difference signal of the image signal together; a second adder 58 adds the other output signal and a second color difference signal of the image signal together. Adding results of the first and the second adders 58 and 59 will be output as a white balance correction value to be applied to the two color difference signals.

Abstract: An automatic white balance device that uses a video signal to obtain the white balance data, and is characterized by using a third video signal, selectively obtained using a first video signal expressing the color signals and a second video signal expressing the luminance, to obtain the white balance.

Abstract: In a television receiver including a feature allowing a user to select a color temperature at which whites will be produced on a display screen, circuitry is provided for altering the gain of the red and blue kine driver stages and simultaneously automatically altering the gain of the R-Y and B-Y color difference signal amplifier, to correct for errors which would otherwise be introduced by adversely altering the B-Y/R-Y ratio.

Abstract: In a projection television system having display elements displaying images of respective colors, a screen on which a color image is formed by magnifying and synthesizing the images of the respective colors, projection lenses for magnifying the images on the respective display elements and projecting them onto the screen thereby to form the color image, with the optical axis of the projection lens for a first color being disposed at a right angle to the screen and the optical axes of the projection lenses for second and third colors being disposed at an angle with respect to the optical axis of the projection lens for the first color, color imbalance is reduced. This is achieved by disposing the projection lenses for the second and third colors so that their optical axes are incident on a point different from the point at which the optical axis of the projection lens for the first color is incident.

Abstract: A method and apparatus for adjustment of the white balance of a CRT display system enabling white balance adjustment to be performed in a short time and a television receiver using the same. The white balance adjustment apparatus has a level adjustment circuit, an attenuation resistor, a video signal output circuit, a coupling capacitor, and a synchronous-signal-tip level clamp circuit and is connected to the cathode electrode. The level adjustment circuit has a variable amplifier which amplifies only the video signal component V, a synchronous signal separation circuit, a variable amplifier for causing attenuation of the horizontal synchronous signal H-SYNC, a signal addition circuit, and an AND gate. In the white balance adjustment mode, the ratio of levels of the video signal and synchronous signal is changed from the usual 0.714:0.218 to, for example, 0.714:0.005.

Abstract: A quality of blue light projected on a screen is detected. A ratio of the detected quantity of the light to a whole quantity is calculated. The calculated ratio is compared with a reference ratio, and a deviation of the calculated ratio from the reference ratio is corrected so as to provide a white balance.