DE2061074A1 - Color television display - Google Patents

Description

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Worshipers: NV KIU.! * ¹ GLUElLAf ₁ ] PENFABRiEKEN

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Registration from: December 10th. 197O

"Color Television Display".

The invention also relates to line-sequential picture reproduction and normalization by a number of lines in the same color during a line trace and one during a subsequent line trace reproduce the same number of lines in a different color, which circuit arrangement a delay circuit for maintenance at the same time contains information to be displayed from successive lines in each line to be displayed during a line trace.

From the British patent 020.796 a picture reproduction ^ abeanordnung of the above type known, whereby to avoid a extensive delay circuit delayed a part of the information to be reproduced for simultaneous reproduction in the delay circuit so that this information is available on a picture display tube for lines to be written at the same time. So this gives

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a loss of information because only part of the information is available at a time becomes available for simultaneous display of a number of consecutive lines.

The invention aims to eliminate this disadvantage.

A line-sequential picture display device according to the invention has the characteristic that the image display device has a video signal input for supplying a coded color television signal, the luminance and color information contains, to which input an input of the delay circuit is coupled, while a Number of outputs, with a delay time of practically one line time between each other, the delay circuit, what number of the number corresponds to lines to be written at the same time, each with a decoding circuit is coupled to maintain the luminance and color information in a form suitable for reproduction, while each of the encoding positions has a corresponding group of outputs, which are per group via a line-sequential switch with a control electrode system a picture display tube is coupled.

The fact that the complete video information is sent in coded form through the delay circuit and that this signal is decoded in different places, a simple Delay switching suffice while the complete information becomes available for each of the lines to be written at the same time.

The stored video signals are preferably of two receive delay arrangements connected in hot air, with each arrangement

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Order is a delay equal to one line period of the clocking system generated and wherein said arrangements are preferably delay lines are.

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The line-sequential display tube i pt preferably a cathode ray tube with a white phosphor screen. Such a tube can, of course, basically be a tube with three KlektrongegenerationsSystems, but preferably a tube with only one electron gun is used together with beam sweep deflection means, which allow the single beam to write three adjacent lines of the field at the same time.

The line on which the incoming signals are displayed can be referred to as a "main" line of the 3-line group, in the sense that it is in the front position with respect to the direction of the image scanning. This line is indicated below as line η and the two preceding lines are referred to as lines (n - 2) and {n - 4) due to an example in which lines {n - 1), (n - 3) etc. belong to another (interlaced) field.

The invention creates the video information required to be stored in a simple and economical manner in that only two delay arrangements are present and which can consist of delay lines. In practice, the collated incoming color video signal can be applied to two such series-connected line delay elements. If the incoming composite color video signal corresponds to line η , the signals at the outputs of the two delay lines will correspond to lines (n - 2) and (n - 4) respectively (with the interlace method, lines (n - 1) and (n - 3 ) received only during the changing fields, as explained above).

During the defrosting time of the line ri it is possible to simultaneously display three lines n, (n - 2}

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and (ii - 4) to write according to the video signals of the one three colors (in the case of a tube with only one electron gun can this by "wobbling" the beam with a high frequency, e.g. that of the ink carrier, can be made over the required width). At the appropriate times, those video signals that e.g. correspond to red lines 11, (n - 2) and (n - 4), in the signal fed to the control grid of the cathode ray tube is blended in. During this entire line time, the switchable filter in front of the white phosphor screen is in red reception mode.

During the following line, (n + 2) the same is repeated, but now the green video signal is combined with the incoming one Color signal and the signals at the outputs of the delay lines taken, the latter now corresponding to lines _n and (ri - 2). At the same time the filter transmits green light.

This process is repeated again during the next line, (n + 4), the display device now displaying the lines (n + 4) »(n + 2) and ri of the blue image, and the filter emitting blue light. During the next line time, the sequence starts from the beginning, producing red lines (n_ + 6), (n + · 4) and (ri + 2), and so on.

In this way, a full color picture can be obtained without any loss any video information.

An embodiment of the invention is in the drawings and is described in more detail below. Show Ee

1 shows a block diagram of a line sequential according to the invention Display,

2 shows an illustration of the writing process in a display tube in a circuit arrangement according to FIG. 1,

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3 shows a display device according to the invention in which simultaneous reproduction of several lines is obtained by beam wobbling »

4 shows the function of a line-sequential filter for Preservation of a line-sequential color reproduction with a monochromatic tube,

5 shows the characteristics of a suitable line-sequential Type of filter according to Fig. 4

Fig. 1 shows the circuit arrangement ait a video input VI, to which a non-decoded composite broad color video information, which is modulated, for example, on a carrier of 10 MHs, is fed. This signal is sent to a first delay line DL1 and then fed to a second delay line DL2 connected in series to ait DL1, each delay line having a delay time which corresponds to only one line period.

The tri-color video input signal becomes immediately one supplied to the first color decoder DC1. The delayed color signal from the output the I) L 1 is fed to a second color deoder DC2 and the twice delayed signal from the delay line DL2 is fed to a third Color decoder DC3 supplied.

Each of the three decoders can be of a conventional form and each has three RQB outputs, which are continuously or almost continuously red, green or blue signals are supplied. Any set of ROB outputs forms part of a · three stables-counter, which is on sohematic Way for the Decodtr DC1 is indicated as SW1, while the switch SW2 and SW3 for the decoders DC2 bsw. DC3 are provided. These switches are operated with the line frequency and at the same time (as by a

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dashed line indicated) by a line synchronous unit LS, see above that the three switches with the red connectors during only one line are connected, then switched to the green connections during the next line period and then to the blue connections during a third line period, etc. The unit LS also controls switchable color filter, which is designated as F.

Of switches SW1 to SW5 is the circuit shown

arrangement by the requirement that the display tube is a special tube with three electron beam generation systems G1, G2, G5, the write three lines of images at the same time, with three beams of the above-mentioned generation systems at the same time through a common deflection system are distracted, shown in simplified form. In the simplified illustration of FIG. 1, the three electron guns fed with red signals during a certain line period ri, but only the electron beam generating system G1 actually gives red Information again, while the electron gun G2 the red information which corresponds to the previous line (n - 2) and the electron beam generating system G3 the red information which belongs to the line (n - 4) which precedes the line (n - 2) reproduces. In the next Line period give the three electron guns green Information again and in the subsequent line period are given by the three Electron gun blue information again. After that, will the cycle repeats with the reproduction of the red information from the three electron beam generation systems.

The system is advantageous in that the image scanning can take place continuously as in a known display system, without any need for a gradual waiting movement of the jet

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len. At the same time, all information belonging to all lines is reproduced and no loss occurs. This should emerge more clearly from Fig. 2, which initially shows a set of three successive lines in red and iwar n, (n - 2), (n - 4) · This is followed by a set of three green lines, which are shown decreased by one line »Ground and this group is followed in the next line period by a group of three blue lines, which are also shifted by another line. These blue lines are followed by a new set of red lines {n + ö), (n + 4) ι (fi. + 2). It should therefore be evident that the first group of lines is in red η to (n_ - 4) and the following group of red lines (n + 6) to (n + 2), so that all six lines under consideration are reproduced in red without any repetition or any omission. The same goes for the green lines, since the first group ends at (n + 2) and the next group starts at (n + 4), and so on.

The circuit arrangement according to FIG. 3 corresponds to that of FIG. with the exception that the more practical solution is a display tube with only one beam generation system is used. Instead of the three beam generating systems according to Fig * 1 the simple beam between three successive rows of lines wobbled. You wobble frequency wira generated by a unit W, which unit a further switch SW4 controls and also a soheaatically represented as BW designated Deflection system gives a vertical beam wobble.

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So the change of the signal from DC1 to DC2 and from DC2 to DC3 becomes carried out at the same time when the simple ray from one line position to another within the group of three lines to be reproduced. ' len is distracted. The switch SW4 is shown schematically as a rotary switch with the same dwell times for all three lines and it is

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possible to obtain such an effect that for sinusoidal fundamental wave W at DW one or more suitable harraonsiche Components are added, so that the wobble deflection signal at DW a Almost corresponds to the shape of the saw tooth.

If the norm of the received color transmission is the NTSC system

each of the three Dacoders in Figs. 1 and 3 can be changed from the normal NTSC

Be type. If the system used is the PAL system, everyone can Decoder the usual phase reversal stage with oscillating synchronous signal

^ Contain transmissions or such a phase inversion stage can be used for

the three decoders must be present together.

As for the durable color filter, it is possible to use the electro-optic effect of pointed crystals. The ideal Characteristic curves of suitable crystal filters are ι

a) low electrical capacitance and low losses;

b) large-angle opening;

c) The electro-optic effect must be longitudinal so that it can be effective over a large area;

d) Effect at low voltage, φ e) Easy to manufacture.

The wide angle requirement limits the materials to cubic crystals, of which the i) n class is a practical example. Hexaain (hexamethylenetetramine (CH ₂ ), N.) Can be used for this purpose using the linear "Pockels" effect.

Such an arrangement is shown in FIG. 4 and can can be used as a source of a light with a variable frequency if the source 2 is broadband, with parts 3, 4 and 5 then as filters with a variable frequency of passage effectively let. If the preferred

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It can be shown (see, for example, "Light" by RWDitohburn, edited by Blackie (1952) volume 12 ( 43) page 386) that the light intensity E, which is emitted by the analyzer 5, is given by E - a ³⁴ cos ² Ca - S) sl ^z sin2 <*. a2 .3 ain * fc & where a divides the amplitude of the light ton of the source 2 at the wavelength \ in air dare, and £. is given through

where e is the thickness of the crystal 4 and / U .. and i ^ _{o are} the refractive indices of the crystal 4 in the fast and long direction, respectively.

When the polarizer and analyzer are crossed, the first term in the equation for E becomes zero and

E - -a ² sin 2 <X sin 2 β. sin * -Hr ^ (. ***, - ^) So provided that the polarization directions of the

Polarizer and analyzer (crossed) not with the preferred directions 2 '1 ν

dfts crystals 4 meet, E is proportional to sin \ /

This change with ^ is a maximum though

Sin 2 c <- sin 2/3 - 1 i.e. if cA. and .3 - 45 "» 135 * · · · · etc.

Then E - -a * sin * (- ~ - ^: ---) TTe.

^ 2/1 ι 3 And E is a maximum if nr β «g, ^, etc.

i.e. if / ^ ₂ - / *, - ^ »I ^ 'ie ^" ^uew ' ^iat *

Similarly, E is zero if / * - .Ut - 0, - · | - ^, etc.

ι e e

So if / ^ n ~ / ** is changed by changing the potential on the electrodes 7 and θ in Fig. 4, the values of \, the

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are transmitted and the values of Λ »which are given by the parts 5, 4, S.
Fig. 4 are stopped, so these parts form a filter, whose pass band (band) for the light from the source
2 in this way can change his (her) position in the spectrum.

There is also the advantage that such crystals do not need to be simple crystals, so that the limitations of the filter format a are much less severe than they are for other switchable color filters which require simple crystals; in some cases it is even desirable to limit the diameter of the cubic crystal color filter to 1-2 inches and a correspondingly small one
To use cathode ray tubes which have been developed for high light intensity so that they can project the color image onto a larger screen with normal dimensions. Such an application of the
The invention offers the advantage of a low power consumption when switching the filter and, in particular, of utilizing the wide-angle properties of cubic crystals.

Appropriate line sequential display can also be used
with an electronic filter system in a display tube with a strip-like phosphor screen and a deflection system in the vicinity of this screen, with one or more electron beams on
these phosphor streaks of the hue to be reproduced during this line scan are deflected. A described line sequential
A display system with a monochromatic tube is also suitable for a projection system for color television display.

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Claims (2)

-11- FHB. 32,021. UIE If ASSPHDCHE ι \ 1. / Line-sequential picture display order during a \ / Line trace a number of lines in the same hue and during a subsequent line trace an equal number of lines in another, which circuit arrangement contains a delay; that the üildwiedergabeanordnung a video signal input for supplying a coded color television signal with luminance and color information includes, which input is coupled to an input of the Verzögerungeachaltung with &, while a number of outputs, with one another a Verzögerungazeit from virtually a line time, the VerzSgerungsschaltung what number the number of simultaneously corresponds to the lines to be written, each is coupled to a decoding circuit to maintain the luminance and color information in a form suitable for reproduction, while each of the encoding circuits has a corresponding group of outputs which are coupled for each group via a line-sequential switch to a control electrode system of a picture display tube. 2, line-sequential picture display device according to claim 1, characterized in that the input and a first output of the delay circuit are coupled via an instantaneous signal path / continue output with the first via a first delay line and am third output with the second via a second delay line. 1 0 9 8 2 ^{6/1 r} 7 5