US 3778810 A
A display device comprising a computer processing unit, a controlling unit including a pattern generator, and a display tube. The pattern generator not only memorizes the predetermined patterns for displaying the normal figures, letters, etc. but also has a read-write function for displaying special figures, etc.
Claims available in
Description (OCR text may contain errors)
United States Patent Ha ashi 1 Dec. 11 1973  DISPLAY DEVICE 3,505,665 4/1970 Lasoff et a1 340/324 A 3,537,096 10/1970 Hatfield  Inventor: Japan 3,428,851 2/1969 Greenblum 340/324 AD  Assignee: Hitachi, Ltd., Tokyo, Japan Primary Examiner-David L. Trafton  Flled' Sept' 1971 AttmeyCraig, Antonelli and Hill  Appl. No.: 178,926
 ABSTRACT  U.S. Cl 340/324 AD, l78/DIG. 22 511 Int. Cl. G08b /36 A T Pmcessmg  Field of Search 340/324 AD umt, a controlling umt including a pattern generator, and a display tube. The pattern generator not only  References Cited memorizes the predetermined patterns for displaying the normal figures, letters, etc, but also has a read- UNITED STATES PATENTS write function for displaying special figures, etc. 3,624,632 11/1971 Ophir 340/324 AD 3,406,387 /1968 Werme 340/324 AD 4 Claims, 4 Drawing Figures FROM CPU OR a 2 @4/ -KEYA/?D MN ADDRESS DVAO/J REG MEMORY REG A/VD l PAR P477 "*1 CONVERTER 6 /V [NH J a E AND 27 i ADDRESS i REG R 242 PAR. SEE CONVERTER PATT MEMORY W17 7 g GEN REG i k 1 AND 3 252 26 '01 4 3 PATENIED 95c 1 I975 sum 3 or F IG. 4
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DISPLAY DEVICE BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION This invention relates to a display device, and more particularly to a graphic device which can easily display any complicated figures. More precisely, this invention is a display device based on the standard television system and displaying any figures.
2. DESCRIPTION OF THE PRIOR ART For example, consider the case where the figure of an automobile is to be displayed in a display device, as is shown in FIG. 1. In FIG. 1, a display surface is divided into n and m sections in X and Y directions respectively. One block of this display surface shown in FIG. 1 is further divided into eight dots in X and Y directions, respectively, as is shown in FIG. 2. FIG. 2 shows the blocks of (i )th row (k 3)the column, (j 5 )th row (k 4)th column, (j 6)th row (k 3)th column, and (j 6)th row (k 4)th column.
For displaying such figures, there has been known a method in which many kinds of display patterns, each for one block of the display surface, are stored in a fixed memory and appropriately combined to represent a desired figure.
According to this method, however, complicated figures cannot be accurately represented unless a great many kinds of patterns such as those shown in FIG. 2 are prepared. When the number of patterns is limited, complicated curves may become unnatural and blocks of complicated figures cannot be displayed unless appropriate patterns are preliminarily stored.
When one wants to represent complicated figures accurately without increasing the number of patterns very much, the size of one block may be selected smaller. Namely, the number of dots per one block may be decreased to simplify the patterns of the respective blocks and thereby to decrease the number of possible patterns for one block. The extreme case is one dot per one block. In such a case, however, the main memory for storing the contents of respective blocks would become very large. This invention intends to eliminate these drawbacks.
SUMMARY OF THE INVENTION An object of this invention is to provide a display device capable of displaying complicated figures appropriately while having a small number of patterns. According to one embodiment of the invention, there is provided a display device comprising a memory for storing signals for selecting a pattern, and a pattern generator for storing the patterns and capable of changing the patterns arbitrarily, i.e. having pattern amending function.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an example of a figure displayed on a display surface.
FIG. 2 is an elevation of some blocks on the display surface of FIG. 1.
FIG. 3 is a block diagram of an embodiment of a display device according to the invention.
FIG. 4 is a block diagram of another embodiment of a display device according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention is shown in FIG. 3, in which a processing unit 1 such as an'electronic computer supplies data of the figure to be displayed to a controlling unit 2 for graphic display, which unit stores the data therein, and the controlling unit reads out the video signal continuously and cyclically corresponding to said data and supplies it to a display unit 3 to display the figure therein. The display unit 3 may be a cathode ray tube.
In the controlling unit 2, a pattern generator 25 stores the patterns of figures, characters, symbols, etc. to be represented in respective blocks of the display surface. The pattern generator contains memories for accommodating the address of one block of the display surface and stores the video signal representing the states of dots for respective scanning lines as in shown in the figure. For example, when one scanning line is made up of five dots, memories such as core memories of five bits are provided in the pattern generator as shown in FIG. 3, corresponding to the address and scanning lines on the display surface. An address register 24 receives the address of the pattern and a timing signal concerning the order of the scanning lines from main memory 22 and a timing control circuit 28, respectively. Then, the address register 24 supplies a signal to the pattern generator 25'to generate the predetermined pattern. The pattern generator 25 supplies parallel video signals as shown in the figure, which are stored in a memory register 26. These parallel signals are converted into a series signal in a parallel-series converter 27 and displayed on the predetermined scanning line of the predetermined block on the display tube 3.
A main memory 22 stores the information of pattern and address, i.e. the information that patterns of which addresses are to be displayed on which locations on the display surface, and reads out the information in synchronism with the scanning line of the display tube, the
. timing being provided by a timing controller 28. A
buffer register 21 stores the write signal when a memory in the main memory 22 is to be altered. Now, the operation of the device will be described taking the case of displaying letter A" in predetermined blocks. First, the image plane to be displayed is divided into respective blocks as is shown in FIG. 1. Then, the addresses of patterns, which patterns are displayed in the respective blocks, are stored in the main memory 22 according to the formation of the image plane. When letter A stored in address (X,Y) of the main memory is to be displayed in said predetermined blocks, the
memory in address (X,Y) is read out from the main memory in synchronism with the scanning on the scanning surface. Thus, the information (X,Y) of address (X, Y) is read out to the address register 24 at the timing. This is done through the fact that the program of the processing unit 1 is made corresponding to the formation of the image plane and that the output of the processing unit I is memorized in the main memory 22. By this procedure, the main memory 22 is synchronous with the scanning on the display tube 3 and the address of the pattern to be represented on the scanned block is successively read out. The content read out from the memory 22 is sent to the pattern generator 25 through the address register 24. When address (x, y) is read out at the predetermined timing, the pattern generator 25 sends signals corresponding to the dots as shown in the figure parallelly to the memory register 26 in accordance with the signal designating address (x, y) and the scanning line in the block.
Namely, for the first scanning line of address (it, y), five bit digital signal of (00100) is parallelly supplied, where 1 represents that the dot is a bright spot and represents that the dot is a dark spot.
Similarly, for the second scanning line of address (it, y), five bit signal of (01010) is supplied. Similar operations are repeated for the third, fourth and fifth scanning lines of the address. Parallel signal (00100) of the first scanning line of address (it, y) is converted into a series signal with respect to time t in the parallel-series converter 27 and then displayed in the first scanning line of the predetermined block of the display tube 3.
In such a display device, the feature of this invention lies in that the pattern generator 25 is also provided with a read-write function for forming and storing a new and appropriate pattern corresponding to the figure to be displayed, as well as the predetermined patterns.
The pattern generator 25 is so constructed that it receives the address and the order of scanning line of a pattern to be written in from the processing unit 1 through the address register 24 and stores the data (pattern) to be written in supplied from the processing unit 1 through the memory register 26.
Therefore, it is only necessary for the pattern generator 25 to first store basic patterns of figures, characters and symbols which are relatively frequently used and not special ones which are rarely used.
A predetermined address or addresses may conveniently be reserved for patterns to be changed in necessity. Hence, the contents necessarily stored in the pattern generator may be very little and yet any complicated figures can be appropriately displayed easily.
FIG. 4 shows another embodiment of the invention in which separate pattern generators are provided for letters, symbols and for figures. Similar numerals indicate similar parts as those of FIG. 3.
A pattern generator 251 stores patterns of letters and symbols such as alphabet and numerals and another pattern generator 252 stores factors of figures in readwrite fashion. References AND 1 to AND 3 are AND gates and [NH is an inhibit gate. Further, DVA 1 is a selection signal of the main memory 22 in the case of altering the memorized content of the main memory, which memorizes the data from the processing unit 1 or the key board in the main memory 22. DVA 2 is a selection signal of the address register 242, which supplies the address designated by the processing unit 1 or the key board to the pattern generator through the AND gate AND 2 and the address register 242, and stores the pattern of the desired figure in the memory of the selected address in the pattern generator sent from the processing unit through the AND gate AND 3 and the memory register 26. The inhibit gate INl-l prevents the address register 242 from accepting the address from the main memory 22 when selection signal DVA 2 exists. DVA 3 is a selection signal of the memory register 26.
Such a system as shown in FIG. 4 is very useful in constructing a display device having a basic structure of a character display as indicated by the dotted line l for displaying letters, symbols, etc. and an optional structure of an image forming function for supplying variable image patterns as indicated by the dotted line II and further capable of adding various functions.
1. A display device for displaying a pattern as an assembly of a plurality of sectional patterns, each sectional pattern being displayed in one of the sections defined by horizontally and vertically dividing a display plane, each section containing a plurality of horizontal and vertical dot positions; said device comprising a processing unit, memory means controlled by said processing unit for storing selection signals for selecting a sec tional pattern for each section of said display plane, and a pattern generator for storing a plurality of groups of digital signals corresponding to various sectional patterns represented by dot positions in the section and generating, according to the selection signal from said memory means and horizontal and vertical timing signals, a video signal composed of the digital signals so derived from the signal groups of the selected sectional patterns as to develop the whole pattern, said pattern generator including means responsive to said processing unit for altering sectional patterns stored in said pattern generator.
2. A display device according to claim 1, which further includes a second pattern generator similar to the first pattern generator, only said first pattern generator having means for altering sectional patterns stored therein.
3. A display device according to claim 1, wherein said means for altering sectional patterns stored in the pattern generator comprises an address register for designating the address of a pattern to be altered and a memory register through which a digital signal to be written at the address designated by said address register is supplied.
4. A display device according to claim 1, which includes a key board for designating the address of data to be written in or the data per se. i