DE1774402A1 - Circuit arrangement for the character display of a lighting system or the like. - Google Patents

Description

6598-68 / Kö / Ro.
RCA 59,336

British Ser. No. 27093/67 177 AA Π?

Filing Date: June 12, 1967 »ttv«,

Radio Corporation of America, New York, N.Y. (V.St.A.)

Circuit arrangement for the character display of a lighting system or the like .

The invention relates to a. Circuit arrangement for the character actor a lighting system or the like.

The well-known mechanical and photographic typesetting processes have the disadvantage that they work relatively slowly and there is little chance that the setting speed can be increased significantly. On the other hand, the application of electronic technology to type setting promises not only a strong increase in the setting speed but also other advantages. Examples can be found at mechanical setting process the point sizes of the characters can only be changed in that one for each point size change a completely new type set is used. Such measures require tent as well as a lot of storage space in order to the large number

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to keep in stock of type sets that are themselves proportionate simple printing operations are required.

In the embodiment described here, an electronic Lichtsetzanlage If the scanning of an image or Character actor, such as a cathode ray tube generated light is projected onto a photosensitive medium, e.g., photographic film, around that formed on the performer Record characters. The individual characters are composed of a number of character sections, which are divided by a multitude of Scan lines that represent characters of a certain point size in a run in a single direction. In the electronic lighting system there are also devices for changing the Point sizes of the characters by changing the length of the scanning line segments as well as the distance between adjacent scan lines. Around the spaces or gaps between To fill the adjacent scan line segments, the individual scan lines oscillations or wobbles across or orthogonal to said one direction superimposed / the amplitude ideser wobble corresponds to the point size of the generated characters. j

In the drawings:)

1 shows the block diagram of an exemplary embodiment of an electronic photocomposition system in a design according to the invention;

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Pig. 2 with the sub-figures 2a and 2b are schematic representations showing the formation of a character in the Pig. I. illustrate;

Fig. 5, consisting of the sub-figures ^ a and ya, schematic representations which illustrate the formation of a character when the point size is changed; and

Fig. 4 is a diagram showing the input-output characteristics of a modulator in the system of FIG. 1 and the differences in the scanning pattern at different bias points of the modulator illustrated.

Fig. 1 illustrates the application of the invention in an electronic lighting system 10. Although the invention is here in Is described in connection with the lighting of types, it can be used in any alphanumeric display system, in which the size of the characters or symbols shown should be variable. Annex 10 contains a display device, e.g. in the form of a cathode ray tube 12, the scanning electron beam 14 of which from a cathode 16 in the electron beam part (not shown) the tube runs out. The scanning beam 14 is applied through the cathode ray tube 12 neck Main horizontal deflection coils 18 and main vertical deflection coils 20 deflected. You can use electrostatic deflection instead work. The scanning beam 14 generates a scanning point or scanning spot 21 in the phosphor on the screen 24 the tube 12 forms the drawing images 22. That from the fluorescent of the

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Light emitted by the screen is turned on through a lens 25 photosensitive medium, e.g. is held.

While per se various methods of forming characters 22 on screen 24 of character 12 are possible, a preferred method used to form characters of high graphic quality will now be described. In this method, each character 22 is composed of a plurality of vertical character sections with scan line segments 30, as is indicated in FIG. 2a for the capital letter * T ". The black segments 30 each comprise those parts of the scan line in which the electron beam 14 is brightly controlled Of course, in the cathode ray tube 12 itself, the segments 30 appear light on a dark background, while in the drawing, for the sake of explanation, the segments 50 are shown dark on a white background End line 35, from where the beam tilts back to baseline 32. For this purpose, the vertical deflection coils 20 are fed with a sawtooth deflection signal from a sawtooth generator 34. The sawtooth signal is fed via a potentiometer 36 which has a number of different settings P ₁ to Pjj which the point size Define the character 22 as will be described later. The output of the potentiometer 36 is before the

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Feed to the vertical deflection coils 20 in a driver amplifier 37 reinforced. With each vertical scan, the electron beam 14 is written a black segment 30 during the time interval da should be light-controlled. For this purpose, the cathode 16 of the tube 12 is tactile or light control signals from an electronic Data processing and control system 40, for example a computer with a stored program. The processing and Control system 40 also contains an auxiliary memory for Store digital signals which produce characters 22 in the various formats or typesets desired. the System 40 also supplies the command signal for keying or controlling the sawtooth generator 34.

At the end of each vertical scan line, electron beam 14 is displaced horizontally by a discrete step. This is done by means of a digital counter 42, which is connected upstream by the processing and control system 40 to successively higher count values. The Vorschaltimpulse are supplied via a switch 43 having a plurality of shift positions P, to P _{n, n} to the settings of the potentiometer P ₁ to P 36 may correspond to changing the dot sizes, as will be explained. The individual continuously higher digital count values are converted in a digital-to-analog converter 44 into an analog signal of progressively higher magnitude or amplitude. The analog signals supplied by the converter 44 are fed to the horizontal deflection coils 18 via a driver amplifier 46. Each analog signal represents the scanning spot

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21 on an invariable horizontal position on your screen of the tube 12 . In this way, as shown in FIG. 2a, each character is composed of a plurality of vertical segments 20 which actually touch one another.

The photographic film 26 is a high oamma (high gradation) film so that the light emitted from the beam spot 21 produces uniformly dense characters on the film 26 during each scanning line. At the end of a line of characters 22 , the spools 28 are driven by a drive motor 48 so that the film 26 is advanced to the next line of print. The processing and control system 40 provides the control signal for switching on the motor 48. Since the film 26 records each segment 30 permanently, no repetition of the display on the cathode ray tube 12 "is necessary. The cathode ray tube 12, the lens 25 and the Film 26 are arranged in a light-tight cassette (not shown), the interior of which is accessible through opening flaps.> \ '

In order to change the point size of the generated characters 22, ''] the length of the black segments 30 and the distance between j the scan lines are changed. In this way the characters 22! be expanded or narrowed to achieve different point sizes without distortion. In order to change the height of the black segments 30, the potentiometer 36 is adjusted from the setting P ,, which produces the sawtooth signal of the smallest amplitude and consequently the symbol of the smallest point size (e.g. point size 4)

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generated, to a corresponding setting up to P _n . The setting P _n generates the sawtooth signal with the greatest amplitude and consequently the largest character (eg point size 16). In a corresponding manner, the horizontal distance between the scanning lines is changed by moving the switch 4 ^ from position P1, the closest distance, to any other position up to Pjj *, the furthest distance. The switch 43 is adjusted automatically by means of a point size information signal supplied by the processing and control system 40. It is therefore expedient to use an electronic switch for switch 45. In the various switch positions P. to Pj-, a different number of stages in the counter 42 is actuated, so that the counter 42 is expanded or narrowed in its range. The settings P. to P _n in both the switch 4) and the potentiometer 36 can be dimensioned in such a way that they produce corresponding and compatible changes in the point sizes of the characters 22.

If the point size is changed, it may happen that the from Scanning spot 21 successively written segments no longer overlap or overlap so that the film is uniform is exposed. In the electronic light setting system 10, a compensation circuit 50 is therefore provided, which one Oscillator 52 coupled to an amplitude modulator 54 is, contains. A control signal supplied by the electronic data processing and control system 40, namely the point

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size information signal is via the switch 4 ^ also the Modulator 54 supplied. The control signal specifies the dot sizes of the character to be generated and is a Glelchstrora preamble signal with a size corresponding to the respective point size. The amplitude modulator 54 can, for example, be a square, Table modulator with a long-range output characteristic 56 be of the form shown in FIG. A diode modulator is sufficient this requirement. That supplied by the modulator 54 is amplitude-modulated e oscillation signal is generated via a driver amplifier 57 an auxiliary horizontal deflection coil 59 * The auxiliary deflection coil 59 is a low inductance coil on the order of of 1 microhenry. For example, you can use a Six-turn coil printed on a glass epoxy substrate use tube 12 on either side of the neck. By the help of the wooden contour deflector 59 is the horizontal deflection of the electron beam 14 caused by the main horizontal deflection coil 18 superimposed an additional horizontal deflection, v ;. -

In order to produce characters of small dot sizes with the electronic light set system shown above, the potentiometer 36 and the switch 43 are set to the position P ₁ . As a result, a control signal is supplied from the processing and control system 40 via the switch 4j5, which biases the modulator 54 to, for example, point 60 of the input-output characteristic 56 in FIG. With this bias to the Arbeltpunkt the oscillation signal 62 is suppressed in the modulator 54, so that

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the auxiliary deflection coil 59 no vibrations are supplied and the horizontal deflection of the electron beam 14 is omitted during the individual vertical deflections. The scanning spot 21 writes on the screen 24 of the tube 12 a straight track corresponding to the track 64 in Fig. 2b. So it goes for a small one Dot size the individual scanning lines in each case only in a single direction.

If the point size is increased, the control signal becomes tense from the system 40 the modulator 54 to, for example, the operating point 66 in Pig. 4 before. In this case, the oscillation signal modulated by the control signal so that the output signal 68 results. This oscillating signal 68 reaches the auxiliary deflection coil 59, so that consequently the individual vertical deflections of the Scanning beam 14 orthogonal back and forth oscillations are superimposed in the form of a beam wobble, as shown in Fig. J5b. The individual scan lines therefore run in essentially two directions, and the gaps or spaces between them Character segments 50 are filled in as shown in Figure 3a. Zelohen of uniform density are produced on these catfish.

The oscillator 52 generates a sine wave 62, as shown in FIG. 4. However, the oscillator 52 can also be so arranged be that it is a trapezoidal oscillation or some other suitable waveform that defines the spaces between adjacent Scan cells able to fill, generate. The oscillation frequency of the oscillator 52 is such that it is sufficient

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is large in order to cause the scanning spot 21 to write an overlapping track in the successive back-and-forth oscillations to prevent white spots from appearing in a black segment.

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ORIGINAL INSPECTED

Claims (8)

π rain claims 1.) Circuit arrangement for a character display system in which a scanning beam scanning a display device generates light, in order to project characters from the display device which are formed on it by a number of character segments, generated by a number of scan line segments, which essentially run in only one direction for characters of a certain point size by means (40, 42, 43, 44) for changing the Dot sizes of the characters by changing the length of the scan line segments and the spacing between adjacent scan lines; and a device (52, 57) "which oscillates the scan lines substantially orthogonally to this one direction superimposed, the amplitude of which corresponds to the point size of the character to be generated, so that the spaces be bridged between adjacent scan lines. 2.) Circuit arrangement according to claim 1, characterized in that the display device has a Cathode ray tube (12) having horizontal and vertical deflection stages (18, 20, 37, 46) for deflecting the scanning beam across the screen the tube contains. 3.) Circuit arrangement according to claim 2, characterized in that the vertical deflection stage a 109817/0639 177U02 Sawtooth generator (34) for the essentially linear Vertlkal-. contains deflection of the scanning beams. 4.) Circuit arrangement according to claim 3 # d a d u r oh characterized, that the horizontal deflection circuit has a counter (42) for generating digital count values and one with the counter-coupled digital-to-analog converter, which converts the digital counter values into invariable analog signals for horizontal adjustment of the scanning beam, as well as an Elnrlohtung (43), the counter for the deflection of the Abtaatstrahls in discrete Periodically advance horizontal steps. 5.) Circuit arrangement according to claim 4, characterized in that the characters dad by certain segments a plurality of the linear vertical deflections in the cathode ray tube are formed. 6.) Circuit arrangement according to claim 5, characterized by one coupled to the cathode ray tube Auxiliary deflection coil (57) and one coupled to the auxiliary deflection coil Interchangeable generator (50), which of the auxiliary deflection coil Alternating signal supplies in such a way that an alternating oscillation is superimposed on the scanning beam, which causes an orthogonal deflection of the scanning beam during the linear vertical deflections. 7.) Circuit arrangement according to claim 6, characterized by a modulator (54) with non-linear input 109817 / 0G39 Output characteristic and by means (52) which supplies the alternating signals to the modulator in such a way that alternating vibrations are generated with an amplitude that is dependent on the modulator will. 8.) Circuit arrangement according to claim 1, characterized by a device (4?) Which biases the modulator to different points of its input-output characteristics, such that the amplitude of the oscillations is changed according to m the point size of the character to be generated. Considered Druckschriftenι USA patent 3 109 10981 7/0639 Blank page