Патент USA US3418525код для вставки
Dec. 24, 1968 3,418,518 E. G. REESE, JR CATHODE RAY TUBE DOT MATRIX SHIFTING Filed May‘ 31, ‘1967 2 sheets-sheet 1 m ubuNM Q o [email protected] 01. E. Q. Ti 329M292 '00 N. WITNESSES: INVENTOR GBQMMQQQ C; - ‘Law [email protected] Edward G. Reese,Jr. MM AU,m N E Y Dec. 24, 1968 E. s. REESE, JR ’ ICATHQDE RAY TUBE DOT MATRIX SHIFTTNG Flled May s1,_ 1967 42, 3,418,518 e9 I e4 2 Sheets-Sheet 2 72 48 DOT MATRIX DOT MATRIX GE NEQATOR GENE$ATOR 5| 62 MAIN 53 82 - MAIN SWEEP ‘“ X POSITIVE sun-"r _54 L_____ E, , 83.5‘; / 60 Y DECODE > .\NEGATIVE SHIFT ' c In: ' ‘64 FIG 3 COMPUTER 242526 27‘ .._ ' i 2 U 5 . ' , FL 24 I ELECTRONIC T|ME-—> ' ELECTRONIC SWITCH SWITCH iv A ' 30 3! ‘ U 9 POSITIVE SHIFT / , ' + I v 55 , ______J 56* NEGATIVE SHIFT) A} ' SWEEP/ , . 35 - ' United States Patent 0 3,438,518 CC Patented Dec. 24, 1968 1 2 3,418,518 A second de?ection means is provided for positioning the cathode ray beam vertically in a plurality of successive dot positions. Circuit means are provided for modifying at least one of the waveforms provided by the ?rst or CATHODE RAY TUBE DOT MATRIX SHIFTING Edward G. Reese, In, Mitford, N.H., assignor to West inghouse Electric Corporation, Pittsburgh, Pa., a cor poration of Pennsylvania Filed May 31, 1967, Ser. No. 642,470 5 Claims. (Cl. 315-22) second de?ection means such that the cathode ray beam may be positioned intermediate the normal dot positions, as dictated by the speci?c character to be displayed on the cathode ray tube face. The speci?c character to be displayed also governs an unblanking circuit means which ABSTRACT OF THE DISCLOSURE 10 causes the cathode ray beam to turn on at speci?c ones of the dot positions. First and second de?ection generators position the cathode ray beam of a cathode ray tube at a plurality of dot positions forming an n x in matrix array with each dot position located at a normal row and column co For more than one character to be displayed, a main horizontal and vertical sweep generator means may be provided to position each complete set of dot positions ordinate of the matrix. A shift circuit is provided and 15 generated by the ?rst and second de?ection means. adds a predetermined positive or negative voltage to the BRIEF DESCRIPTION OF THE DRAWINGS de?ection generator voltage to cause a shifting of the FIGURE 1 illustrates a typical dot position matrix for normal dot position, in accordance with a speci?c char displaying a character; acter to be displayed. By providing a shifting circuit for FIG. 2 illustrates the dot matrix of FIG. 1 displaying both the horizontal and vertical sweep a normal dot posi 20 the character N; tion may be shifted to eight other positions depending FIG. 3 is a block diagram illustrating an embodiment upon the combination of shift signals. The cathode ray of the present invention; beam is unblanked at certain dot positions in accordance FIG. 4 illustrates various waveforms at certain points with a character to be written, so that the character may 25 in the circuit of FIG. 3; and be displayed on the cathode ray tube face. FIG. 5 illustrates the shift circuit portion of FIG. 3 in somewhat more detail. BACKGROUND OF THE INVENTION Field of the invention.-The invention relates to a cathode ray tube display system, and in particular, to a read-out display where various characters including letters, symbols, numerals, punctuation marks etc. are written on the face of a cathode ray tube for visual or photographic inspection. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGURE 1 there is illustrated a 5 x 7 dot matrix array wherein each of the 35 dot positions have been given a respective number 1 through 35. Each dot position represents a point on a cathode ray tube face where the cathode ray beam would strike (if it were turned on) as the beam is de?ected horizontally and Description of the prior art.~——Various methods are em ployed to display characters on the face of a cathode ray tube and one of the most basic methods is the dot matrix method. In the dot matrix method a stepping waveform vertically by de?ection circuitry. Travel of the cathode positions the cathode ray beam in a rectangular dot posi a scan along the Y axis. tion array and the cathode ray beam is unblanked at each dot position forming the character to be written, so that the cathode ray tube face will light up in a plurality of tiny areas, thus forming the character. ray beam in a horizontal direction is a scan along the X axis whereas movement of the beam vertically represents Normally, the de?ection circuitry provides voltage waveforms which would position the cathode ray beam at dot position 1 and thereafter at the next successive dot position 2 and thereafter at the next successive dot Generation of extremely high quality characters de position 3, etc. The present invention includes shifting pends upon the number of dot positions generated. With means whereby the normal dot position may be shifted fewer dot positions there is an inferior diagonal quality to a point intermediate normal dot positions. By way of in such letters as A, K, M, N, R, V, W, X, Y and Z. example, consider dot position 18, a positive shift along In fact, in many displays there is only one dot position the X axis will move dot position 18 to dot position 18E to represent the entire diagonal line. In other instances 50 whereas a negative shift along the X axis will position rounding off of certain letters such as B, C, D, G, J, O, it to a point designated 18W. Similarly, a positive shift P, Q and U is desired. along the Y axis will move dot position 18 to 18N where A problem arises however in that to generate enough as a negative shift will move it to 185. By combinations dot positions for a high quality array, proportionally of a positive and negative shifting along the X and Y more decoding circuits are needed thereby increasing 55 axis, dot position 18 may also be moved to positions cost and complexity. In addition to the increase in the de ISNE, 185E, 188W and 18NW. coding circuits, the unblanking circuits increase in com One method of shifting a normal dot position would plexity and there is a proportional increase in memory be to provide an analog voltage proportional to a desired requirements. variable shift distance. However this would require a If enough dot positions are generated, then the beam 60 somewhat complex analog de?ection circuit. As an alter energy requirements of the cathode ray tube increase native a dot position may be shifted by a predetermined with writing speed. A general object of this invention is to provide a high quality character display which obviates the need for the additional circuitry as required in the prior art. SUMMARY OF THE INVENTION There is described a character display apparatus for a cathode ray tube system which includes a ?rst de?ec and ?xed amount upon the occurrence of a shift signal. For most applications this would result in a high quality character display. By way of example, if the distance between successive dot positions is D then a normal dot position may be caused to move 1/3 D. In FIGURE 1 therefore and considering the distance between dot posi tions 18 and 17, the cathode ray beam may strike the cathode ray tube face at any one of four points, that tion means for positioning the cathode ray beam of the 70 is, dot position 18, dot position 18E, dot position 17, and cathode ray tube horizontally in a plurality of successive dot position 17W. With both vertical and. horizontal shift dot positions in accordance with a de?ection waveform. ing a total of 9 different dot positions is possible; consid 3 3,418,518 4 ering 2 normal dot positions, such as 17 and 18 there fore, a total of 18 different dot positions is possible. The provision of shifting a dot position to a point M; the distance between normally successive dot positions results in a capability to display high quality characters. In FIG network which may include various memory and decoding circuits which then provide the necessary timing and un blanking signals vfor a proper display of the character. In the present invention not only are the unblanking signals provided for character display but means are additionally URE 2 there is illustrated a character, the letter N, dis played on a 5 x 7 matrix such as illustrated in FIGURE 1. provided for modifying at least one of the waveforms of When the scanning is such that the cathode ray beam would be at dot position 1 the beam is unblanked, that is the beam is turned on such that the beam strikes the cathode ray tube phosphor and dot position 1 is caused to glow. The Scanning proceeds until dot position 5 where upon the cathode ray beam is unblanked to cause excita tion of the cathode ray tube phosphor. The beam is then de?ected in a Y direction to dot position 6 where it is unblanked and then scanned from right to left until dot position 9 at which time a negative shift is provided such that the cathode ray beam strikes the cathode ray tube the dot matrix generators for positioning the cathode ray beam to a point intermediate the normal successive dot positions as dictated by speci?c characters to be displayed. In FIGURE 3 provision is made for modifying the output of generators 42 and 48 by means of shift circuitry 50 and 51 respectively. Each of the shift circuits 50 and 51 receive respective positive and negative shift signals on lines 53 and 56 from the decode network 60 which is operable not only to provide the shift signals but to provide an un blanking signal to the unblanking ampli?er 62 for turning on the cathode ray beam. The decode network 60 may pro vide respective shift and unblanking signals in response to an instruction from computer 64 or alternatively the face at dot position 9W after unblanking. The cathode ray beam is unblanked at subsequent dot positions indi 20 decode circuit 60 could be an integral part of the computer cated, including dot positon 12E shifted positively from dot position 12, dot position 24W shifted negatively from dot position 24 and dot position 27E shifted positively from dot position 27 to thereby provide four extra lighted 64. The output of the shift circuit 50 is a positive or nega tive voltage on line 67 and is combined with the output of tions in a second row, the next plateau labelled 11-15 maintaining the next 5 dot positions in a third row etc. The combination of waveforms a and b therefore applied to the de?ection circuitry of the cathode ray tube is oper trons 1 and 5. The ?rst unblanking signal of waveform c the matrix generator 42 in the summing circuit 69, the output of which is eventually fed to the de?ection ampli areas in the diagonal of the character N instead ‘of just ?er 72 for sweeping the cathode ray beam in the X direc— one lighted area, that is dot position 18. tion. Similarly, when the shift circuit 51 receives a positive In FIGURE 3 there is illustrated apparatus for dis or negative shift input signal, a positive or negative voltage playing high quality characters on a face of a cathode ray of a predetermined value is provided on output line 74 tube in accordance with the present invention. Letter des and is combined with the output of the matrix generator ignations in FIGURE 3 refer to corresponding waveforms 48 in summing circuit 75. The de?ecton ampli?er 78 is of FIGURE 4. The apparatus includes a cathode ray tube responsive to the output of the summing circuit 75 for unit 37 including a cathode ray tube 38 the face of which controlling the cathode ray beam in the Y direction. is illustrated and upon which is displayed a plurality of The apparatus thus far described is operable to provide characters 40‘. In order to position the cathode ray beam horizontally 35 positioning voltages for a cathode ray beam for the dis play of a single character. In the majority of instances it is in a plurality of successive dot positions for displaying desired to display a plurality of characters so that a mean a single character, there is provided a ?rst de?ection means ingful message maybe visualized. Accordingly, there is in the form of dot matrix generator 42 which is operable provided de?ection means in the form of main sweep de to provide a staircase waveform illustrated as solid curve ?ection circuit 81 for the X axis sweep and main sweep a of FIGURE 4. Each voltage plateau represents a speci?c circuit 82 for the Y axis sweep, the outputs of which are X coordinate for the cathode ray beam and each plateau combined in summing circuits 84 and 85 with the outputs has been given the number corresponding to the respective of summing circuits 69 and 75, respectively. The main dot position such as illustrated in FIGURE 1. In other sweep de?ection waveforms therefore when combined words, a de?ection waveform provided by the dot matrix with the dot matrix generator waveforms have the effect generator 42 having a magnitude of level 1 will position the cathode ray beam at dot position 1; with a voltage 45 of providing a plurality of rows of dot matrices each matrix having the form as in FIGURE 1. In other opera level at plateau 2 the cathode ray beam will be poistioned tions, the main sweep de?ections may be governed by a de at dot position 2, etc. With the waveform a, the cathode coded computer instruction so that a character may be ray beam sweeps (facing the tube 38) from left to right displayed anywhere on the face of the cathode ray tube for the ?rst row, from right to left for the second row, such as in aircraft identi?cation and control situations. from left to right for the third row, etc., although, obvi Waveforms c and d of FIGURE 4 illustrate the neces ously other de?ection waveforms could be provided for sary signals provided by the decode circuit 60 for dis positioning the cathode ray beam horizontally in a plu playing the character N as illustrated in FIGURE 2. With rality of successive dot positions. In an analogous manner, second de?ection means for positioning the cathode ray reference therefore to FIGURES 2, 3 and 4, waveform c beam vertically in a plurality of successive dot positions appears on output line 88 of the decode circuit 60 and comprises a plurality of precisely timed pulses. For ease are provided and takes the form of the dot matrix gener of understanding each pulse has been given the number ator 48 which provides the staircase waveform b illustrated corresponding to the dot position where the pulse occurs in FIGURE 4 with the ?rst plateau designated 1~5 main for displaying the character N. By way of example, in the taining the ?rst 5 dot positions in a ?rst row, the second ?rst row the cathode ray beam is unblanked at dot posi plateau designated 6-10 maintaining the next 5 dot posi is labelled 1 and occurs at the same time that waveform a is at the ?rst plateau. The next unblanking signal labelled 5 occurs when the waveform a is at the plateau labelled 5. able to provide the dot position matrix of FIGURE 1. 65 After plateau 5 has been reached waveform b drops down to plateau 6-10 for writing in the second row of the dot Dot matrix generators such as 42 and 48 for generating matrix. The third unblanking signal labelled 6 occurs staircase waveforms are well known to those skilled in the when waveform a is at plateau 6 and the next unblanking art. Having the capabilities of providing a dot position signal occurs at dot position 9. At dot position 9 however, matrix, means are generally provided for unblanking, the decode circuit in accordance with the present inven that is turning on the cathode ray beam at speci?c dot tion receives on line 54 a negative shift signal and the positions in accordance with characters to be written. shift circuit 50 provides a negative pulse labelled 9 in Generally in such display systems an instruction to display a certain character or characters may emanate from a char acter generator or more often, from a computer. The in waveform d to modify waveform a. This modi?cation shows up as a decrease in voltage of plateau 9, the de_ struction so provided is received by some sort of decoding 75 crease being illustrated in dotted lines labelled 9W and 5 3,418,518 being equal to 1/3 the difference in voltage between plateaus 9 and 10 since, it will be remembered, in the embodiment of the present example the dot position is 1. Display apparatus for displaying characters on the face of a cathode ray tube comprising: (A) ?rst de?ection means for providing a ?rst de?ec tion waveform for positioning the cathode ray beam horizontally at a plurality of successive normal dot operable to move 1/3 the distance between normal succes sive dot positions. The normal unblanking sequence con tinues up until dot position 12 at which time the decode circuit provides a positive shift signal on output lead 53 to the shift circuit 50 which then provides an output signal labelled 12 in waveform d serving to modify the de?ec positions; (B) second de?ection means for providing a second tion waveform a. This modi?cation shows up as a 1/3 in crease in voltage and is represented by the dotted plateau 10 designated 12E. This general sequence is continued until the entire character is displayed. Since the character N does not require any vertical or diagonal shifts, waveform e rep resenting the output of shift circuit 51 does not provide any modifying voltages to the output of dot matrix gen erator 48 although for those characters which require a vertical or diagonal shift, waveform b is modi?ed by such 6 I claim as my invention: 15 pulses as was waveform a by the output of shift circuit 50. 20 With respect to the pulses of waveform c it is to be noted that the pulses do not commence when waveform a changes to a next plateau, but occur at a time after the plateau has been reached. This is to ensure that all tran sients have decayed and then when unblanking occurs the 25 cathode ray beam will strike the cathode ray tube face at exactly the required dot position. That is, by giving wave form a time to settle to the respective plateaus, accurate positioning of the cathode ray beam may take place. To perform the function of shift circuits S0 or 51 any 30 one of a variety of circuits may be utilized, one such illustrative arrangement being shown in FIGURE 5 which additionally shows one type of summing circuit in some what more detail. The shift circuit 50 includes electronic switches 90 and 91 connected respectively to positive 35 potential +V and to negative potential —V. The electronic switches 90 and 91 are normally in an OFF condition such that neither of the voltages +V or ~V appears at circuit point 92. Upon the application of a positive shift signal on lead 53 from the decode circuit 60, electronic switch 40 90 will close thereby applying the +V voltage through resistor 96 to circuit point 92. Similarly, if a negative shift voltage is provided on line 54, the electronic switch 91 de?ection waveform for positioning the cathode ray beam vertically at a plurality of successive normal dot positions; (C) shift circuit means for modifying at least one of said waveforms for positioning the cathode ray beam to a position intermediate normal successive dot posi tions in accordance with speci?c characters to be dis played; and (D) unblanking circuit means for causing the cathode ray beam to turn on at certain ones of said positions in accordance with speci?c characters to be displayed. 2. Apparatus according to claim 1 wherein: (A) the shift circuit means is operable to supply posi~ tive and/or negative voltages during the course of a character displayed; and which includes (B) signal combining means for combining at least one of the de?ection waveforms with said positive and/ or negative voltages. 3. Apparatus according to claim 1 wherein: (A) the distance between successive normal dot posi tions is D; and (B) the shift circuit means is operable to shift the normal dot position by 11/3 D. 4. Apparatus according to claim 1 wherein: (A) the ?rst de?ection means includes a ?rst staircase waveform generator; (B) the second de?ection means includes a second staircase waveform generator; and which includes (C) decode circuit means for providing output signals in accordance with particular characters to be dis played; (D) a ?rst shift circuit means responsive to the output of said decode circuit means for changing the level of particular steps in said ?rst staircase waveform, and (E) a second shift circuit means responsive to the to the circuit point 92. output of said decode circuit means for changing the The output of dot matrix generator 42 is applied through level of particular steps in said second staircase wave resistor 99 to circuit point 92 which forms the input to form. summing ampli?er means 101. Since the output of sum~ 5. Apparatus according to claim 1 which additionally ming ampli?er means 101 is the inversion of the input signal, there is provided an inverting ampli?er 103 the 50 includes: output of which constitutes the output signal of the sum (A) main horizontal and vertical sweep generator ming circuit 69. means for positioning each set of dot positions pro Although the present invention has been described with vided by the ?rst and second de?ection means. a certain degree of particularity, it should be understood that the present disclosure has been made by way of ex 55 References Cited Will close, applying the voltage —V through resistor 97 ample. The provision of shifting voltages for certain characters to be displayed in combination with a dot posi tion matrix generation means may be accomplished with various other types of circuitry. In addition, the principles applicable to shifting various dot positions may be applied UNITED STATES PATENTS 3,090,041 5/1963 Dell _____________ __ 340——324 RODNEY D. BENNETT, Primary Examiner. to the main X and Y sweeps for variably positioning each 6 character from a normal character position on the tube face. Other modi?cations and variations of the present T. H. TUBBESING, Assistant Examiner. invention are made possible in the light of the above 3l5—24; 340-324 teachings. U.S. Cl. X.R.