摘要:
Projection television display device includes three monochrome projection television display tubes (20, 21, 22) each having a display screen (24, 25, 26) which is provided on the inside of the display window (23) and luminesces in a different color. Each tube has an optical axis extending perpendicularly from the center of the display screen, the optical axes (33, 34, 35) of the three display screens being co-planar. The axes (34, 33) of the display screens of the first and second tubes (20, 22) coincide and the axis (35) of the display window of the third tube (21) constitutes the main axis of the device, the axis being perpendicular to the two coincident axes (33, 34). Two flat dichroic intersecting reflective mirrors (27, 29) extend perpendicularly of the plane and through the point of intersection of the axes, each at an angle of 45.degree. with the main axis. The first mirror (27) reflects the image of the first display screen and the second mirror (29) reflects the image of the second display screen into the direction of the main axis and away from the third display screen, interference filters being disposed between the display screens and mirrors for passing the desired color of light. With interference filters disposed between the luminescent material of the display screens and the display windows, the reflection greatly increases for light rays constituting an angle of more than 20.degree. to 35.degree. with the normal of the filter. When there is substantially no transmission up to 90.degree., there is a gain in brightness by a factor of 1.5 to 2, a gain in contrast by more than a factor of 2 and also a considerable color improvement and reduction of color errors when the conventional green and blue phosphors are used.
摘要:
A display tube comprising in an evacuated envelope (1) a display screen (7) provided on the inside of a display window (2) in the wall of the envelope (1), which display screen (7) comprises luminescent material (13), and a multilayer interference filter (12) is provided between this material and the display window and comprises a number of layers (HL) which alternately are manufactured from a material having a high (H) and a material having a low (L) refractive index. If the filter is composed substantially of 6 to 30 layers, each having an optical thickness nd, wherein n is the refractive index of the material and d is the thickness, which optical thickness is between 0.2.lambda..sub.f and 0.3.lambda..sub.f and preferably between 0.23.lambda..sub.f and 0.25.lambda..sub.f, wherein .lambda..sub.f is equal to p x.lambda., wherein .lambda. is the desired central wavelength which is selected from the spectrum emitted by the luminescent material (13) and p is a number between 1.15 and 1.45, a display tube is obtained in which the luminous efficiency in the forward direction is at least 40% larger than in a tube without such a filter. Color improvement and gain in contrast also occur.
摘要:
A display tube comprising in an evacuated envelope (1) a display screen (7) provided on the inside of a display window (2) in the wall of the envelope (1), which display screen (7) comprises luminescent material (13), and a multilayer interference filter (12) is provided between this material and the display window and compises a number of layers (HL) which alternately are manufactured from a material having a high (H) and a material having a low (L) refractive index. If the filter is composed substantially of 14 to 30 layers, each having an optical thickness nd, wherein n is the refractive index of the material and d is the thickness, which optical thickness is between 0.2 .lambda..sub.f and 0.3 .lambda..sub.f and preferably between 0.23 .lambda..sub.f and 0.27 .lambda..sub.f, wherein .lambda..sub.f is equal to p x .lambda., wherein .lambda. is the desired central wavelength which is selected from the spectrum emitted by the luminescent material (13) and p is a number between 1.18 and 1.36, a display tube is obtained in which the luminous efficiency in the forward direction and at small angles for the central wavelength of the phosphor is at least 40% larger than in a tube without such a filter. Color improvement and gain in contrast also occur.
摘要:
A projection television system comprising an array of three projection television display tubes (14) luminescing in red, green and blue, a focusing lens (16) associated with each tube and a display screen (12) on which the respective optical images are merged to form a single multicolored image. At least one of the display tubes (14) has a multilayer interference filter (46) between the phosphor (30) and the faceplate (20). In order to imprve the light output at the corners of the display screen (12), the cut-off angle of the first filter layers is varied between the center and the corners thereof, for example by increasing the optical thickness of the filter layers relative to the center.
摘要:
A projection color television system having an improved resolution and luminance comprises red, green and blue color emitting tubes, the electron beams of which are focused onto their respective screens. In order to compensate for the strong saturation of the blue phosphor, and simultaneously to take advantage of the relatively fast decay of this phosphor, the blue color emitting tube is a single gun, multispot display tube. The increase in light output obtainable from the blue color emitting tube is matched by providing interference filters in the red and green color emitting display tubes and optionally in all three red, green and blue emitting tubes.
摘要:
A projection television display tube comprising in an evacuated envelope a display screen on the convexly curved inside of a display window in the wall of the envelope, which display screen comprises a layer of luminescent material and a multilayer interference filter between said material layer and the display window, the filter comprising a number of layers which are alternately high refractive index (H) and low refractive index (L). The filter is composed of at least 6 layers, each having an optical thickness nd, wherein n is the refractive index of the material of the layer and d is the thickness, which optical thickness is between 0.2.lambda..sub.f and 0.3.lambda..sub.f, wherein .lambda..sub.f is equal to p x .lambda., wherein .lambda. is the desired central wavelength which is selected from the spectrum emitted by the luminescent material and p is a number between 1.18 and 1.32.
摘要:
A projection television system comprising an array of three projection television display tubes (14) luminescing in red, green and blue, a focusing lens (16) associated with each tube and a display screen (12) on which the respective optical images are merged to form a single multicolored image. At least one of the display tubes (14) has a multilayer interference filter (46) between the phosphor (30) and the faceplate (20). In order to imprve the light output at the corners of the display screen (12), the cut-off angle of the first filter layers is varied between the center and the corners thereof, for example by increasing the optical thickness of the filter layers relative to the center.
摘要:
A method and device for recording information signals on a partly recorded writable record carrier (11), e.g., an optical disc. An information signal represents at least one information unit. The record carrier has a recording track which includes preformed track position information indicative of locations for recording the information units. From the information signal, a modulated signal is generated having successive frames, each frame including a synchronizing signal. The modulated signal is recorded at a one of the locations, while maintaining a fixed relationship between the track position information and the synchronizing signals. In the event that the location is after and adjacent to an already recorded location, the recording is started at a link position (31) before the end of a last frame of the earlier recorded information signal, at a predefined distance before a first synchronizing signal (30) of the modulated signal.
摘要:
An optical recording method and recording apparatus using this method is described in which an optimum write power of a radiation beam in the apparatus is set by writing a series of test patterns on an optical recordable medium, forming a read signal from the patterns, reading a preset value of the derivative of the modulation of the read signal with respect to the write power from the medium, and processing the read signal together with the preset value to derive an optimum value of the write power.
摘要:
The invention relates to an optical disc for recording data at a constant density, so called CLV (Constant Linear Velocity) or at zoned CLV. The disc has headers distributed along the disc on regular angular positions, a so called CAV (Constant Angular Velocity) pattern subdividing the track in track portions for recording an amount of data proportional to the radial position of the track portion concerned. Address information included in the headers is provided at the data density, which is CLV. The apparatus comprises header detection means for detecting the headers at the CAV locations, and for recovering position information from the headers at CLV density. Data sectors do not start at headers and are not fitted regularly between the headers, but start and stop at arbitrary positions which are calculated from the known amounts of data recordable in the track portions.