US3581302A

US3581302A - Apparatus and method for providing graphical configurations by sequentially directing a radiant energy beam to present image positions

Info

Publication number: US3581302A
Application number: US710349A
Authority: US
Inventors: Edwin R Kolb; Robert M Horvath
Original assignee: Harris Intertype Corp
Current assignee: Harris Corp
Priority date: 1968-03-04
Filing date: 1968-03-04
Publication date: 1971-05-25
Anticipated expiration: 1988-05-25
Also published as: DE1907967B2; FR1600594A; DE1907967A1; JPS5140456B1; GB1265731A

Abstract

A phototypesetting system employs a cathode-ray tube to present characters of typesetting quality wherein each of the characters displayed is generated by directing the cathode-ray tube beam to a series of locations, each immediately adjacent its previous location, where the beam is energized for a predetermined period of time. A character memory, such as an optically encoded disc, supplies digital information to electronic circuitry which initially locates the beam within a character field and then directs the beam sequentially to additional locations, each of the locations immediately adjacent the previous location, thus forming characters from a series of illuminated spots. Additional deflection signals are supplied to control the cathode-ray tube to move the beam automatically to the next character position after each character has been formed in preparation for the writing of subsequent characters.

Description

United States Patent Inventors Edwin R. Kolb University Heights; Robert M. Horvath, Parrna, both of, Ohio 110,349 Mar. 4, 1968 May 25, 1971 Appl. No. Filed Patented Assignee Cleveland, Ohio Harris-Intertype Corporation APPARATUS AND METHOD FOR PROVIDING GRAPHICAL CONFIGURATIONS BY SEQUENTIALLY DIRECTING A RADIANT ENERGY BEAM TO PRESENT IMAGE POSITIONS Primary Examiner.lohn W. Caldwell Assistant Examiner-David L. Trafton Attorney-Yount & Tarolli ABSTRACT: A phototypesetting system employs a cathoderay tube to present characters of typesetting quality wherein each of the characters displayed is generated by directing the cathode-ray tube beam to a series of locations, each immediately adjacent its previous location, where the beam is energized for a predetermined period of time. A character memory, such as an optically encoded disc, supplies digital information to electronic circuitry which initially locates the beam within a character field and then directs the beam sequentially to additional locations,'each of the locations immediately adjacent the previous location, thus forming characters from a series of illuminated spots. Additional deflection signals are supplied to control the cathode-ray tube to move the beam automatically to the next character position after each character has been formed in preparation for the writing of subsequent characters.

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sum 15 HF 17 FIG-11B L lo LD 1oo'-s 2oo-s soous DELAY LINE \82 4oo-s TOTAQ. DELAY soon APPARATUS AND METHOD FOR PROVIDING GRAPHICAL-CONFIGURATIONS BY SEQUENTIALLY DIRECTING A RADIANT ENERGY BEAM TO PRESENT IMAGE POSITIONS RELATED APPLICATIONS Reference is hereby made to U.S. Pat. application Ser. No. 59l,734, filed Nov. 3, 1966, entitled TYPESE'I'IING SYSTEM; Ser. No. 608,l6l, filed Jan. 9, 1967, entitled EN- CODER READ OUT APPARATUS; and Ser. No. 805,l05, filed concurrently herewith entitled CHARACTER MEMORY.

BACKGROUN D OF TH E INVENTION High speed phototypesetting devices using cathode-ray tubes are commonly employed to display characters forsubsequent recordation on photographic film. Different types of character generators have been used to form these characters, such generators including character grids used inconjunction with a scanning video tube, or core matrix or magnetic drum memories which are used to generate the characters by scanning the character field in a raster scan pattern either by forming the characters from a series of lines with the cathoderay tube beam being energized only in those areas where the character is present, or by turning the beam off and on as it is moved in a series of incremental steps in the raster pattern.

One disadvantage of the raster scan type of character generating systems lies in the fact that valuable time is being wasted while the beam control circuitry attempt to direct the beam to areas which form no part of the character, and where the beam therefore remains deenergized.

This invention relates to an improved typesetting apparatus wherein the characters may be fonned by moving a beam of energy, such as the electron beam of a cathode-ray tube, to a plurality of discrete locations in a predetermined sequence and energizing he beam of energy at each of those locations for a predetermined'period of time. The beam is therefore never directed to an area which forms no part of the character, with the result that the character is generated in a minimum of time.

Each of the characters in a font of type is represented by digital information recorded in character memory means,

such as an optical character memory adapted to be rotated at a relatively high rate of speed. The digital character information is recorded as a series of bytes, each consisting of three bits, each byte forming an instruction to cause the beam to move to one of the locations immediately adjacent its previous location. The character is therefore formed by focusing a beam of energy onto the energy responsive surface of the tube and moving the beam to a plurality of predetermined locations by modifying the output of a circuit which controls the vertical and horizontal location of cathode ray tube beam in discrete increments. Although a three-bit code is used to move the beam to a new location and expose the film, as opposed to the single digit code used to control the intensity of the beam in those character generators wherein the characters are formed by scanninga portion of the cathode-ray tube face in a raster ,pattern, it has been found that the time for character generation is nevertheless reduced since the beam is never directed to a location which does not form part of the character.

A group of codes are associated with each character track on the optical character memory to supply control information to the electronic circuitry used in the formation of the characters. For example, it has been found that more rapid access to the character information may be accomplished by dividing each character into a plurality of sections, and supplying each of those sections with a code identifying the starting coordinates of that section with respect to the remainder of the character. A more complete explanation of this type of character generation may be found in the above mentioned .copending US. Pat. application, Ser. No. 805,l05. Also, the

number of sections required to form a complete character may be included as part of the control information, thus providing for flexibility in the generation of the character.

The control information may also include codes indicating the normalized width of the character, which, when multiplied with the actual horizontal point size of the character being displayed, will give a signal which will cause the beam of energy to be moved to the proper horizontal location after the formation of that character is completed. Still another portion of the control data may indicate the point size of the recorded character which, when multiplied with the vertical an horizontal point size, will produce signals controlling the size of the character formed as well as the time during which the beam is energized in each location.

Accordingly, objects of this invention are to provide an improved method and apparatus for generating characters of typesetting quality by energizing a beam of energy to form a spot and positioningthe spot at a plurality of predetermined, immediately adjacent locations within a character field in information from a character memory, each of the locations forming the character being identified by reference to its immediately preceding location, without directing the beam into areas which form no part of the character; to provide a method and apparatus for generating characters of typesetting quality wherein the characters are formed from a plurality of spots, the spacing between spots being consistent within a character, and the spot size relative to the total size of the character being predetermined to produce characters of high resolution; to provide a method and apparatus for forming characters of typesetting quality wherein the digital information representing a character is stored on a cyclically moving memory, and wherein rapid access to the character information is provided by dividing each character into a number of sections with the location of each section within the character field being so identified that a complete character maybe formed from any sequence of sections which make up a complete character, and with the generation of each section being accomplished by moving the beam sequentially to a series of predetermined locations first with reference to the starting location of that section and afterwards with reference to the previous location of the beam; and to provide a typesetting methodand apparatus wherein characters may be displayed an area at a time, with the intercharacter spacing being automatically provided in response in a stepwise manner to the size of the character actually formed as indicated by the point size of the character stored in the character memory and selected by a control record. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view of a system for generating characters of typesetting quality on the face of a cathode-ray tube with a part of the system shown as electrical block diagrams;

FIG. 2 represents a character memory and illustrates the recorded information representing a character being repeated about the character memory with each repetition being divided into a number of sections;

FIG. 3 is an enlarge view of a portion of the character memory disc shown in FIG. 2, with two clock tracks and a single discrete character track being shown;

FIG. 4 is a diagram showing the direction in which the cathode-ray-tube. beam moves in accordance with the numerical instructions derived from the character memory;

FIG. 5 is an enlarged view of the letter a made up of several numbers, each number representing an instruction for moving the cathode-ray tube beam to a location immediately adjacent its present location to form the character;

FIG. 6 is an enlarged view of a portion of the letter a shown in FIG. 5 showing how the cathode-ray tube beam is moved in response to specific instructions from the character memory counter, the distribution gates, the skip counter and the section counter;

FIGS. A through 10D are detailed logic diagrams showing the control logic of the character generator of his invention;

FIGS. 11A and 11B are detailed logic diagrams of the clock used to control the character generator of this invention in response to clock signals from the character memory;

FIGS. 12A and 12B are detailed logic diagrams showing the x and y up-down counters, the PREDlPS register and the normalized width register.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FlG.'l which shows in part a block dia gram of a device for generating characters of typesetting quality on a cathode-ray tube, the character storage memory is shown schematically at 10 and is formed from a transparent disc having alphanumeric characters optically stored thereon as a plurality of digital bytes which may be presented in a sequential manner. The character storage memory may be similar in its construction and arrangement of tracks containing character information to that character storage memory shown and described in copending US. Pat. application Ser. No. 608,l6l, filed Jan. 9, 1967, and assigned to the same assignee as the present invention. In that copending application,

an optically transparent character storage memory is.

described as containing six bands, with each of the bands con taining 35 discrete tracks having optical marks permanently recorded thereon.

While a singlediscrete track is herein described as containing the information for a single character in serial form, it is, understood that a plurality of tracks, usually adjacent, may also be used to represent in parallel form the information required for the generation of a single character. In either case, the information for character generation will be regarded as being contained in a single discrete track in this application. It is also understood that a plurality of character storage memories may be provided and that a pickup device is associated with each of the bands on each of the character memories. Either mechanical or electronic switching may be employed to select the character storage memory to be used and the particular band within the selected memory.

The digital information contained within the tracks on the character memory 10 is illuminated by a light source 11 and the image of a plurality of these tracks is projected onto a fiber optic pickup assembly 12 where that image is optically magnified and focused onto individual fiber optic bundles l3 and transmitted by means of these bundles 13 to photomultiplier tubes 15, one photomultiplier tube for each of the tracks within a band. The character memory 10 is rotated by means of a motor 16 to cause relative movement between the character memory 10 and the pickup means 12.

In the embodiment described herein, two of the photomultiplier tubes are used to sense the timing tracks contained on the character memory 10 and generate electrical pulses which are thereafter used to provide the timing or clock signals for the remainder of the character generating apparatus, as will be described in detail hereinafter. The remainder of the photomultiplier tubes sense the digital information contained in corresponding tracks on the character memory 10, and the electrical signals produced thereby are used to control the position of a beam of energy, such as the electron beam in a cathode-ray tube, to form a character by moving the beam to a plurality of predetermined locations within a character field. Appropriate switching circuitry is provided to select the photomultiplier output to direct this character generating function in response to external commands.

The electrical output of each photomultiplier tube 15 is applied to a character generator circuit 20, the function of which is to sense the digital information contained within a selected one of the character tracks and convert that information into control signals, hereinafter described as character generating signals, which are then applied to the vertical and horizontal

deflection amplifier circuits

21 and 22 for the cathode-ray tube 25. The character generator circuit 20 also controls the energization of the cathode-ray tube beam generating means and energizes the beam only in those areas which form a part of the character to be displayed.

A control record, such as a magnetic tape 27, passes through a tape reader 28 where it is read and the electrical output fed into a buffer 30. Of course, other types of control means, such as the output of a computer or paper tape, may be used in supplying the control signals to the buffer 30. The control record 27 contains information relating to, but not limited to, character selection, intercharacter and interword spaces, and leading instructions when the system is used as a phototypesetter.

The buffer 30 accepts information from the control record at its optimum read out rate, and then transfers that information to the decoder circuit 31 at a rate which can be accepted by the phototypesetting system. Different control functions will take differing amounts of time, and even the generation of certain characters will take longer than the generation of other characters. The output of the decoder 31 is applied to the control circuit 35 which in turn supplies the character positioning signal to the horizontal and

vertical circuits

21 and 22 for positioning the electron beam of the cathode-ray tube, and thus the entire character, prior to the generation of each character. Selection among the characters within a band on the character memory 10 is determined by another output from the decoder 31 to the character selection circuit 36.

In the preferred embodiment of this invention, the cathoderay tube displaying the characters uses electromagnetic deflection means, and both the character positioning and character generating signals are applied to modify the'current through the same deflection means. It has been found that this arrangement is to be preferred, especially when characters of typesetting quality are to be generated. Thus, amplifier circuit- 21 supplies the current through an electromagnetic coil 37 controlling the vertical location of the beam, and in like manner, the horizontal amplifier circuit 22 controls the current through the electromagnetic coil 38 controlling the horizontal location of the beam. Both the vertical and horizontal amplifier are responsive to voltages supplied by the control circuit 35 and the character generator circuit 20. Thus, the character positioning signals position the beam to locate the character horizOntally and vertically on the face of the cathode-ray tube while the character generating signals actually develop the character on the face of the cathode-ray tube. When used in a phototypesetting operation, the image of the characters so formed are recorded by photographic materials such as film or paper.

In a typesetting system the characters developed on the face of the cathode-ray tube 25 in H6. 1 will have different widths. The letter a, for example, may be assigned a width value of Wu, while the letter i has a width value of Wi and the letter m has a width value of Wm. Each of these width values will depend upon the type and style of the font being generated, but

normally characters such as those illustrated in FIG. 1 will be positioned automatically after the preceding character has been generated by relocating the cathode-ray tube beam, the distance which it moves being determined by the width of the previously formed character. With the type of character generator described herein, each of the characters stored on the character memory 10 has a width code associated therewith, and this width code is multiplied by the horizontal point size of the character to be generated, as determined by a signal from the control record 27. This multiplication occurs in the control circuit 35, and the horizontal character positioning signal is modified to reposition the cathode-ray tube beam after the character generation has been completed.

Referring now to FIG. 2, the character memory 10 includes a pair of clock tracks 40 and 41, an several character tracks 42. In FIG. 3, the portion of the character memory 10 includ-

Claims

1. Apparatus for providing a graphical configuration by sequentially directing a radiant energy beam to preset image positions to form a desired pattern of images on a radiant energy responsive surface to define a said configuration, and comprising: means for sequentially supplying a plurality of sets of beam direction command signals with each said set providing only the direction for the beam to proceed from one image position the next of said preset image positions along either a path parallel to one of first and second mutually perpendicular coordinate axes or askew therefrom; deflection control means for sequentially deflecting said beam in accordance with said command signals from one said image position to the next said image position so that for each directional command said beam is positioned so that adjacent image positions are spaced by predetermined increments along paths respectively parallel to said axes, and beam control means for unblanking said beam only at each of said preset image positions.

2. Apparatus as set forth in claim 1, wherein said deflection control means includes circuit means for varying the incremental spacing between adjacent image positions along paths parallel to at least one of said axes.

3. Apparatus as set forth in claim 1, wherein said sets of beam direction command signals are coded signals, each set being representative of a specific beam direction and said defection control means includes direction command signal decoding means for decoding each set of coded command signals and providing therefor either a first coordinate signal representative of commanded directional movement along a path parallel to said first coordinate axis or a second coordinate signal representative of commanded directional movement along a path paralleL to said second coordinate axis or both said first and second coordinate signals representative of commanded directional movement along a path askew from said axes.

4. Apparatus as set forth in claim 3, wherein said first and second coordinate signals are each either positive or negative signals representative of the relative direction along said axes, and first and second reversible counter means for respectively receiving said first and second coordinate signals and providing first and second count signals respectively indicating the commanded first and second coordinate axis position of the image position corresponding to the commanded directional movement.

5. Apparatus as set forth in claim 4, wherein said first and second count signals are digital signals, first and second digital to analog means for respectively receiving said first and second count signals and providing firs and second analog deflection signals for incrementally deflecting said beam for each said set of directional command signals.

6. Apparatus as set forth in claim 5, including means for varying the magnitude of said first and second analog deflection signals dependent upon the location of said beam on said beam on said beam responsive surface to compensate for nonlinear beam responsive characteristics so that said incremental spacing along each of said axes is maintained relatively constant as configurations are formed at different locations on said surface.

7. Apparatus as set forth in claim 4, wherein a said configuration is formed in sections with each section defined by a plurality of said images and wherein said sequentially supplying means provides said plurality of sets of beam direction command signals for one section at a time and provides for the commencement of each section a coded pattern of section starting signals.

8. Apparatus as set forth in claim 7, wherein said sequentially supplying means also provides a distinctive signal representative of the number of said sections required for each configuration, and counting means for counting the number of sections formed on said surface to insure that the correct number of sections are formed.

9. Apparatus as set forth in claim 1, including means for positioning said beam along one of said axes prior to providing the next configuration on said surface, accumulator means effective to control the output from said configuration position controlling means to establish the location at which the entire configuration will be formed; and means to update said accumulator means after each said configuration is formed so that said positioning means repositions said beam dependent at least in part on the width width along said one axis of the last said configuration formed on said surface.

10. Apparatus as set forth in claim 1, wherein said surface is the display surface of a cathode-ray tube and said beam is said tube''s beam and said deflection control means includes: first circuit means for respectively effecting positioning of said beam to major positions along one of said coordinate axes at which desired configurations are to be formed and in accordance with beam position command signals; and second circuit means for effecting additional positioning of said beam along said axis in dependence upon the selected major position of said beam to compensate for nonlinear beam response characteristics of said cathode-ray tube.

11. The method of forming a graphical configuration on a radiant energy beam responsive surface by directing the beam in a predetermined sequence to preset image positions, and comprising the steps of: sequentially providing a plurality of coded beam direction command signals each providing only directional information for displacing said beam to proceed from one image position to the next image position along either a path parallel to one of first and second mutually perpendicular coordinate axes or askew therefrom; decoding each of said command signals to obtain either a first coordinatE signal representative of commanded directional movement along a path parallel to said first coordinate axis of a second coordinate signal representative of commanded directional movement along a path parallel to said second coordinate axis or both said first and second coordinate signals representative of commanded directional movement along a path askew from said axes; displacing said beam for each said coded directional signal in accordance with the decoded first and/or second coordinate signals so that said beam is positioned to the next preset image position with the distances between adjacent image positions being constant along paths parallel to said respective axes; and unblanking said beam only at each said image position to thereby form the desired graphical image.