Abstract: A method for increasing the speed at which characters may be written onto a liquid crystal display of the type in which a plurality of write cycles must be applied to each picture element that is to become visible. The character writing operation is divided into two or more stages each of which preferably includes an equal number of write cycles. During at least those times when an operator is entering characters more rapidly than they can be fully written, the different stages of the writing operations for two or more successive characters are performed simultaneously to increase the apparent writing speed of the display.

Abstract: A system for generating a real time perspective view of the terrain lying along an aircraft's flight path accesses terrain data stored in a digital map generator and converts the data into a perspective representation of the terrain on the face of a suitable display such as a cockpit instrument panel CRT. The stored map data that is accessed provides, in real time, information pertaining to elevation features of the terrain over which the aircraft is flying, so that upon conversion to a perspective presentation to the pilot, there is provided a real time perspective image of the contours of the terrain as though the pilot were looking out a windscreen at the terrain in high visibility conditions. The invention also is capable of providing perspective scene rotation and translation (corresponding to roll and pitch of the aircraft).

Abstract: An active matrix-addressed liquid crystal panel comprising plural matrix picture elements is disclosed. The defects of a picture caused by a short between a row electrode and a substrate is inconspicious because each row electrode controls the picture elements belonging to the row as well as the picture elements belonging to the neighboring rows.

Abstract: In a device for the illumination of a passive display element a flat light guide element made of plexiglass is arranged immediately behind the passive display element. The guide element has a peripheral edge which is sloped. A carrier plate is provided in the device, which has light-emitting diodes in chip form mounted thereon. The light-emitting diodes apply light onto the peripheral edge of the light guide element.

Abstract: A computer-generated image system that is described in the Disclosure has a videoprocessor circuit with an integrator circuit to assign a predetermined identification to each edge of each face of any image that is to be displayed. Also, it has a "skip-over logic" circuit to identify any area in the face of any image to be displayed that requires no further intensity modification.Perhaps a key to the success of this arrangement in accordance with the described invention is its provision of a signal modifier circuit to apply a pre-determined intensity modification factor to any area not identified by the skip-over logic circuit. By this arrangement, any area that is to be displayed behind a translucent area will be visible although at a reduced intensity.

Abstract: A video display control unit controls characters to be displayed on a sequential scanning display unit (4). Namely, it reads address-specifying information and attribute information from a video memory (5) along scanning sequence of a screen in a continuous and address-unit time-divisional manner on the basis of address signals from a memory address counter (6). The read attribute information is outputted on a multiplex bus (42) through a gate (34) and delayed by a predetermined period by a pipeline register (40) to be supplied to a video signal encoder (18). The read address information is supplied to a character generator (16) so that character information is read from the character generator (16). The character information is outputted on the multiplex bus (42) through a gate (36) and delayed by a predetermined period in a pipeline register (38) to be supplied to the video signal encoder (18).

Abstract: The present invention provides apparatus and methods which are most advantageously used in conjunction with a computer display system incorporating the use of a Z-buffer to provide three dimensional hidden surface elimination. A buffer memory is provided which is sufficiently large such that each display element (pixel) on the display is represented by a 16-bit Z value. The Z value corresponds to the Z axis depth of the object at the particular point corresponding to the pixel. The buffer comprises a plurality of dynamic random access memories (D-RAMs) having two operation modes: Normal and Read-Modify-Write (RMW). A counter/pointer register is provided which successively addresses values in the buffer representing successive pixels along scan lines of the display. A graphics processor is provided with coordinates defining a three dimensional image to be displayed and, for each point of the object, computes a current Z.sub.c value beginning at an initial coordinate address in memory.

Abstract: Pixel representations for each of a plurality of superimposed (or splitscreen) display portions are accumulated in a band buffer prior to being transferred to the display. The actual pixel representations are made available to the band buffer from an image memory, with addresses provided by a display list memory. This system minimizes the need for buffering and high speed storage to service the video, by addressing first the display list memory, then in turn using the content of the display list memory to address the image storage, and then in turn using the content of the image storage as the actual pixel representations for accumulation in the band buffer. Two band buffers operate alternatively. The current band buffer is feeding a band of pixel representations to the video shift register while the next band buffer is accumulating the pixel representations of the subsequent video display band. The band buffer accumulates actual pixel representations equivalent to the related band of the display.

Abstract: A cordless light pen for use with a cathode ray tube display screen as a data input for a digital computer. Contained within the exterior barrel of the pen is a depressible tip having a core made from a plastic which has been treated and whose index of refraction causes light entering in a direction parallel to the longitudinal axis of the core to pass through. The other end of the tip is operatively disposed relative to a light sensor. Also contained within the barrel of the cordless pen is a circuit card containing circuitry for amplifying, filtering and shaping the signals from the light sensor and to discriminate between signals due to the CRT sweep in the field of view of the tip and ambient noise. The so-called "hits" occasioned by the passage of the CRT beam past the tip member when it is depressed cause an IR LED to be energized to produce a directed beam of IR energy. The IR energy is transmitted to a receiver positioned to detect it, provided the light pen is held on the face of the CRT screen.

Abstract: There is provided a display control circuit including a central processing unit and display memory elements provided corresponding to respective data lines of the central processing unit. The display memory elements respectively have a plurality of data input terminals supplied with bit orders beforehand. As the display memory element, a large capacity readable/writable memory having a bit width per address such as 4 or 8 is used.Each bit per one address of said display memory element is assigned to an element belonging to each plane in the depth direction which constituted an individual picture element on the display screen. And one picture element is represented by one address of one display memory element. As a result, the number of display memory elements can be decreased.

Abstract: Display data is read out from a display memory (2) and the display data thus read out is written in the buffer memory (8). Then, in a time sharing manner relative to the writing, the display data is read out from the buffer memory (8), and a smoothing processing is carried out on the basis of the display data thus read out and the display data read out from the display memory (2).

Abstract: A method and an apparatus for operating a display monitor to prevent burn-in of the screen. The entire display is imperceptibly moved in both vertical and horizontal directions by changing the temporal relationship between the information signal transmitted to the monitor and the signals used to synchronize the scanning of the screen.

Abstract: Programmable pin drivers allow PROM pins to be individually programmed and regulated to specified voltages and currents. Each pin is assigned a voltage multiplexer to select a regulated voltage and a power amplifier to supply current. The source voltage to the power amplifier is determined by the maximum and minimum reference voltages needed by the device under test. This allows a full 70 volt range of pin voltages to be seleced without substitution of pin driver parts, although individual parts have a dynamic range of only about 40 volts, and reduces thermal power dissipation. It also allows very fast microprocessor-driven switching of input voltages to pins, by changing the reference voltages assigned to the individual pins' voltage multiplexers.

Abstract: A scanning CRT graphics video display system is disclosed in which a graphics display controller reads formatted information signals into a refresh memory in a read-modify-wire mode and reads the stored information out of the refresh memory in a display mode. During the display mode the information in the memory is provided on a common data bus for sequential reading into four different shift registers having different bit capacities with the different bit capacities effectively implementing predetermined delays such that the shift registers will properly simultaneously read out the information that was sequentially loaded into the shift registers. A programmable logic sequencer provides address select signals in addition to address signals provided by the graphics display controller so as to address four different memory planes in the refresh memory, and the address select signals are also utilized to sequentially enable the loading of the four shift registers.

Abstract: A technique is disclosed for use in an electronic raster-scan display system, for generating characters of variable size using a stroke-vector technique. An incoming data signal defines the type of character to be displayed, the horizontal X and vertical Y character field dimensions, the character drawing point, and any character rotation or reflection. Using that part of the data signal that defines the character type as a memory address, a character microprogram is retrieved containing a stroke-vector character mask and a stroke resolution factor representing the number x of horizontal stroke-vectors in a straight line and the number y of vertical stroke-vectors in a straight line that are used by said character mask to represent said character within a normalized character field.

Abstract: An eraser for an electronic blackboard. System whose erasing area is variable according to the size and accuracy of the figure to be erased. The eraser includes a main unit carrying a small area erasing unit, and a large area erasing unit which is detachably engaged to the main unit. Detectors installed in the main unit detect when the eraser is touched on the surface of the board, and/or that the large area erasing unit is being used, and send an appropriate signal to the system controller.When the system controller receive the signal, it blanks the memories corresponding to the area covered by the erasing units and erases the corresponding area of figures displayed on the display unit.

Abstract: A display system (10) receives from a light source (12) a sequence of images, each representing a different depth plane of a subject, and selectively reflects each image from its corresonding one of plural light direction modulators (16 and 18) to synthesize a three-dimensional image of the subject. Each modulator is positioned along an axis (20) at a location that corresponds to a different depth plane. Each modulator reflects the first image incident to it and transmits the succeeding images in the sequence. In a display system having N+1 depth plane images, each of N modulators comprises a variable optical retarder (34) and a liquid crystal chiral cell (36). The N modulators reflect left-circularly polarize light and transmit right-circularly polarized light. An N+1 modulator preferably comprises a liquid crystal chiral cell and reflects light incident to it. An alternative embodiment (50) develops full color images.

Abstract: The disclosure relates generally to a computer generated synthesized imaging system. More particularly, the invention relates to a method and apparatus for providing fast access to a two axis memory wherein consecutive data elements in both row and column orientation of a data set represented as a matrix may be obtained at a rate faster than the access time of memory elements utilized. A speed-up of access speed by a factor N may be achieved, where N is a power of 2 (2, 4, 8, 16 . . . ). The memory elements are organized in N independently addressable banks of data memories. The matrix oriented data is mapped into these N banks such that any N contiguous data elements of any row or any column reside in different memory banks. Any N contiguous data elements of any row or column may then be accessed within the access time of any one memory bank. The N contiguous data elements may then be read from memory in a single memory cycle.

Abstract: A novel stroke-vector character generator is disclosed for generating characters or the like in a raster-scan video display system. An external data signal defines the type of character to be displayed, the character field dimensions, the character drawing point, and any character rotation or reflection. Using that part of the data signal that defines the character type as a memory address, the character generator retrieves from memory a character microprogram containing a plurality of encoded binary valued stroke-drawing directives. These directives are instructions to a decoder how to generate all of the shape dependent attributes for a series of chain related stroke-vectors that define the overall shape of the character to be displayed. Once defined in the system, each stroke-vector is scaled so that the character cell size matches the character field dimensions defined by the external data signal.

Abstract: A novel method is disclosed for use in an electronic raster-scan display system, for generating characters using a stroke-vector technique. An incoming data signal defines the type of character to be displayed, the character field dimensions, the character drawing point, and any character rotation or reflection. Using that part of the data signal that defines the character type as a memory address, a character microprogram is retrieved containing a plurality of encoded binary valued stroke-drawing directives. These directives are instructions detailing how to generate all of the shape dependent attributes for a series of chain related stroke-vectors that define the overall shape of a character to be displayed. The encoded drawing directives are decoded and sequentially applied to a set of initial values that define an initial virtual stroke-vector, and thereby generating all of the character-shape dependent stroke attributes to for a series of chain related stroke-vectors that define a character shape.