DE2157144C3 - Circuit arrangement for influencing the ratio of the display intensity of the various fluorescent colors of a single-beam color picture tube - Google Patents

Description

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zpiiräum changed in the sense of the desired Farb.nten-SSälmisses, and that this beam intensity modulation circuit is connected to a transistor emitter follower (Q4) to which the color image * o signal is supplied, connected diode clamping circuit (D 1, AS. * 6, C3) for clamping the The peaks of the blanking pulses become one with. As is well known

Aode "s ^ ^Wl " ⁿ for the color- _translucent screen carrier _inside te different fluorescent _{bombardment must} light up the electron beam ^ ,, _{colors , arranged according to} the total number of luminous

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speaking is supplied to the desired color intensity ratio, and that the Diode clamping circuit, the transistor emitter follower and the attenuation network with one of the both control electrodes (grid or cathode) of the picture tube are galvanically coupled in such a way that that the DC bias on the control path of the picture tube is dependent on the bias the diode (Dl) changes in the sense of a brightness setting with a stable black level.

2. Circuit arrangement according to claim 1 for use for a color picture tube whose screen has blue, green and red fluorescent elements, in which the luminous efficiency of the blue and green fluorescent elements is greater than that of the red fluorescent elements, characterized in that the damping network (Al, Rl , Ql, A3, Ql, Q3) is synchronized with the scanning movement of the electron beam in such a way that the amplitude of the color television signal is reduced only during those periods of time during which the electron beam sweeps over the blue and green phosphor elements. 3. Circuit arrangement according to claim 1 and 2, 1 \ - _ .. i, a ^ .p, r, <. T HaR the damping network

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Sequence red, blue, green, can be detected, the individual fluorescent elements are sometimes made sufficiently and placed at a sufficiently close distance from one another, one can achieve that stana ^VO " ^C1 ". . _Groups , which are detected by the electron-SS £ Äo ^G nXlauf , can be regarded as I in picture element, since the color of the three successive phosphors are integrated by the eye of the observer who is at the normal distance from each other. It is also known that the color that the eye sees depends on the brightness of the light emitted by the three phosphor components, so that the component is 5 seconds _{when the green} .

The light emitted individually is approximately twice as bright as the light S emitted by the red fluorescent substance, and six to ten times as bright as the light emitted by the blue fluorescent substance appears. There are also different degrees of "white" depending on the de. Mi chung of the colors red, green and blue, as well as according to the different efficiencies of the individual phosphors themselves. This allows _59/0 Grun 30 / _o Roi NND 11 "'Blue at a certain Wirkungsgrac and _11/0 mau _{a White ff the Deit}

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contains the time periods and that these resistors are switched on by transistor switches (ρ 1, Ql) synchronously with the application of the blue and green fluorescent elements in the new damping mechanism.

6,

The invention relates to a circuit arrangement as it is assumed in claim 1.

^{rul (} j ⁿ . _us .p _{S 35 2} 4 013 is a circuit ^{arrangement, J n} ° ^Lr ^ _{flow of the} ratio of the reproduction to the '** ™ different fluorescent colors a ^ ™ ^ _{color tube is} described, in which _{three elreniUe} damping networks for Justierun of Strahlstromcinsatzes and balancing the Untei differences are required in the luminous efficiency of different dye elements. the three different "Ηρπρπ Dämrjfunesnetzwerke necessary, we dene ⁿ ^ _'ra ^g _instell mainly By J

The screen grid voltage is changed. A further development of the invention is characterized in the sub-adjustment of the screen grid voltage but requires claims

a subsequent adjustment of the control voltage. In the drawings, an exemplary embodiment is shown in FIG

and the video signal amplitude. It must therefore be explained in more detail for each invention. It shows

Phosphor at the same time the screen grid voltage, the 5 F i g. 1 shows the block diagram of an embodiment

Control grid voltage and the video signal amplitude of the circuit arrangement according to the invention,

be adjusted. F i g. 2 shows a simplified equivalent circuit diagram of a part

The object of the invention consists in the combination of the circuit arrangement according to FIG. 1,

increase the white balance over the entire gray F i g. 3 a detailed diagram of the circuit

already through a circuit-wise compensation arrangement according to FIG. 1 and 2 and

the differences in the efficiency of the three luminous F i g. 4 is a circuit diagram of the input amplifier of FIG

fabrics. This object is achieved by the features of the circuit arrangement according to FIG. 3.

Claim 1 solved. rj _as block diagram according to FIG. 1 illustrates

While the circuit according to US-PS 35 24 013 an embodiment of the invention in application no getreinte control in the three color channels 15 on a color television receiver, in which either, this is possible with the invention, where the three different colored fields or three verAmplitude des Color picture signal in which the reproduction different colored lines on the screen of the time periods corresponding to the individual colors are written one after the other and each of the fluorescent colors are set separately, the amplitude of the video signal is changed. That can. In addition, the invention enables the overall image to be controlled without affecting the video signal mixture with negatively directed synchronization impairment of the once set ratio Brightness at a stable black level over that of the point of the receiver at which the blanking impulses, the diode clamping circuit applied bias voltage. Furthermore, in the known circuit, each of the luminance signals and color difference signals are present and is capacitive on the fluorescent material at the same time screen grid voltage, control terminal stage 10 coupled, which changes the most negative part of the grid voltage and video signal amplitude of the blanking pulse signal clamps to a potential, needs to be in the case of the invention in which the correct direct current level is found of the video circuit only the video signal amplitude changed 30 signal results. The output signal of the clamp stage 10 to become. At the same time, an emitter follower stage 20 is fed in a very simple manner, which is used to reduce the brightness of the image via that supplied to the clamping diode, to reduce the loading effects of the shunt bias voltage, since the circuit components in the downstream signal damping circuit are galvanically coupled to the picture tube network. A to the output of the are, the bias voltage so in addition to their function 35 emitter follower stage 20 connected resistor .R ₁ clamps the black level directly on the control of the picture tube is part of the signal attenuation network with the sub-electrode is effective. In the known video signal controlling the color picture tube, the white-circuit resistors, which serve to balance the amplitude over the gray area, change through switching despite the greater expense there.

the two damping networks more critical than with 40. Blocks 30, 40 and 50 are the shunts

according to the circuit, which represent considerably less, each of which by working one of three

Adjustment settings required. Pulse generators 60, 70 and 80 between the resistors

The compensation is preferably carried out if the level R ₁ and a reference potential point 75 (for example different phosphor efficiencies by sequencing ground) can be switched. The pulse generator 60 generates a resistance control, so that the amplitude of the 45 a pulse when the red fluorescent elements of the video signal control voltage for the single-beam single-beam color picture tube are excited to light up the color picture tube in successive scanning lines, and is connected to the shunt 30. or scanning rasters (fields) according to the NTSC, which is changed together with the resistor R ₁ as a system. The various resistances attenuator act that the video signal control can be switched electronically in parallel to the signal path when the electron beam changes, so that a variable shunt resistor detects red fluorescent elements. Correspondingly, the result is created by changing the video signal pulse generator 70 during the scanning of the blue light amplitude and the relative cathode ray intensity of the material elements, in that it controls the secondary light output of the individual phosphors in the same way. Terminal 40 switches on, so that the video signal control is particularly suitable for the activation during the detection of the blue fluorescent element in a color television receiver for hermening through the electron beam. The desired proportionality of the white pulse generator 80 is changed switches the shunt 5C playback; However, it can be used quite generally in order to control the video signal during those cases where, during color reproduction, scanning the green fluorescent elements with a single-beam cathode ray tube changes the amplification Colors are desired to pulse sequentially, depending on which one is used. For example, with a single-beam picture tube, switching mode either with the line or with the raster, the red and white images as output information alternating frequency, so that at a given time in each electronic data processing system only one of the shunts 30, 40, 5C generates, with the help of the damping 65 according to the invention is switched into the damping network and the switching of the electron beam of the picture tube is controlled in its intensity by switching on the individual shunts so that the red proceeds correctly,
would be amplified compared to the white rendering. In this way the pulse generator 6 generates (

its the red shunt 30 in the attenuation that switch that is currently on the screen

Network switching pulse corresponds to essentially reproduced color. The initial

at the same time when the red signal information comes to the signal of the attenuation network then as at

Input terminal 51 reached. In the next line of the arrangement according to FIG. 1 to video amplifier 90,

or the next raster ends this pulse, and 5 where the signal voltage on the level for the control

the pulse generator 70 generates its value required for the blue plane of the single-beam color picture tube

final 40 switching-on pulse is essentially strengthened.

the same time that the blue signal information for the circuit diagram of FIG. 3 contains an integrated

Input terminal 51 reached. On the next line, integrated input amplifier circuit of the RCA type

or the next grid ends that of the Impulse io CA 3001. Such an input amplifier, its

generator 70 generated pulse, and the pulse generator 80 is a circuit diagram in FIG. 4 is suitable for the

produces its green shunt 50 enabling use in conjunction with that described herein

Impulse that occurs with the arrival of the green signal information circuit. That fed to input 51 in FIG

mation at entrance 51 coincides. The mixed video signal passes through the capacitor C ₁

Stand R ₁ thus forms together with the secondary 15 to the connection contact 6 of the integrated circuit

Conclusions 30, 40 and 50 a damping network, CA 3001. The output generated at connection contact 11

This is done simply by changing the values of the three output signals via a capacitor C ₂

Shunts coupled in the appropriate order to the base of a transistor Q _t. To the base

independent of the desired level of the red, blue of the transistor Q ₄ are also connected to ground

or green signal level can be set. 20 resistor A ₄ as well as the cathode of a semiconductor

The output signal of the damping network rectifier D ₁ , the anode of which then reaches a video amplifier 90, where the capacitor C ₃ is connected to ground. The total signal modulation of the color picture tube (anode of the rectifier D ₁ is also increased at the connection through the output 100). Although not shown at the junction of two resistors A ₅ and A ₆ , the pulse generators 60, 70, 25 must be closed, which are coupled between a first supply voltage and 80 to the video source (+ 6 V) and ground at the input 51. The contradicting signal mixture must be synchronized so that the corresponding A ₅ can be adjusted for the purpose of setting the bias voltage of the pulses for red, blue or green in each case to the transistor Q ₄ . The arrangement can be generated with the times when the red, blue and green capacitors C ₂ and C ₃ , the resistors R _t , R $ video information is processed. 3 ° and R _B and the rectifier D ₁ forms the terminal

The simplified equivalent circuit according to FIG. 2 stage 10 in F i g. 1. The rectifier D ₁ clamps the

illustrates even better the operation of the negative peaks of the blanking pulses to the through the

Arrangement. _{The voltage divider resistors A 5} and R _s generated by the emitter follower stage 20 through

The clamped video signal supplied is fed to the resistor C ₃ filtered voltage.

stood R ₁ , which together with the resistors R ₂ , R ₃ 35 The transistor Q _t is connected as an emitter follower

and R _it the red shunt 30, the blue parallel and ensures that the effectiveness of the clamping stage

End 40 or the green shunt 50, if present, additionally in the signal processing

forms the damping network. The three oppositely switched shunts are retained.

states R ₂ , R ₃ and R _t can be switched by switches S ₁ , S _2. The transistor Q ₄ is connected to the collector with its collector

or S ₃ , the synchronized pulse generator 60, 40 first supply voltage source (+ 6 V in the shown

70 and 80 in FIG. 1 correspond to the attenuation transistor polarity) and mn its emitter via a

network must be switched on. When the synchronous resistor R _{7 is connected} to a second voltage source

Sized switches S ₁ , S ₂ and S _{3 are} open, have the opposite polarity (-4 V) connected.

Resistors R ₂ , R ₃ and i? ₄ essentially none The emitter follower transistor has a high resistance

Impact. However, switches S ₁ , S ₂ 45 become the base input during operation. Its emitter is above that as well

and S ₃ one after the other, always one each. Resistance R ₁ (which corresponds to resistor R ₁ in FIG. 1

closed so that when switch S _{1 is} closed, and 2 is comparable) with the shunt arrangement

the clamped video signal is connected by the amount ^ -% If negative ^ directed impulses change ^{6 6} ■ ^R i + ^R 2 high level with the video signal mixture is attenuated or weakened. If 50 output 51 is then coupled in, the arrangement adds the resistor A ₂ variable, so the output as far as described so far can add an output voltage of the damping network to a direct current component to the output signal, since the rectification value is between zero and the voltage of the ter D ₁ clamps on this instead of the blanking pulse, clamped video signal and thus the red signal- Since these direct current components are adjusted accordingly by the input level. Likewise 55 switched resistors in the same ratio as is, if the synchronization is such that the processed video signal is attenuated, the switch S ₂ supplies closed and the switches S ₁ and S ₃ arrangement a variable direct current control, are opened, the clamped video signal to which the modulation level of the video signal pro

Amount ^ f ^ attenuated and the blue _signal output 6q j ^^ f "° ^{ieS dieDt ah} brightness control ^dei

changed accordingly. If on the basis of the in FIG. 3 preferred embodiment shown

Synchronization then the switch S _{3 is} closed and the embodiment of the invention is intended to control the signal output

the switches S ₁ and S _{2 are} opened, this is done for the red fluorescent elements without any

clamped video signal damped by the amount ^ V _fi damping occurs because the efficiency of many of the

^{0 6} R ₁ + Rj ^{6 F} 65 time-available red fluorescent substances are considerably low

and as a result, the green signal modulation is corresponding to the corresponding efficiency of blue and unc

changed, at a given time each green phosphors. So although the invention c

always only one switch is closed, namely the circuit in general for changing the signal

7 8

level achieved with both red and blue as well (with the arrangement shown). The Tran-Grün is set up, with the special output resistors Q ₁ to Q ₃ , as mentioned above, with the guide form according to FIG. 3 only the blue and these positively directed pulses are sequentially attenuated by the green signal modulation. Namely, they are not driven with either line or grid change frequency in shunts 40 and 50 for blue or green according to FIG. 5 in such a way that they are sequentially F i g. 1 in FIG. 2 alternately conduct as variable resistors R _2. If the transistor switch after and R ₃ present, while in F i g. 3 are not made conductive to each other, the bypass circuit 30 according to FIG. 1 corresponding contradicting resistance R ₂ , R ₃ (and the red side stand is present. End, if present) switched on and thereby the

The variable resistor R ₂ is changed between the io degree of damping. The end of the resistor R _{1 video signal facing away from the transistor Q 4} attenuated in this way is then fed to the video amplifier with the and the collector of a further transistor Q _1, transistors Q ₅ and Q _6,
switched. The base of the transistor Q ₁ receives via The transistor Q ₅ is connected with its base to the one resistor A ₉ , which connects this base to the end of the resistor R _{1 remote from the first transistor Q 4} , a supply voltage source (+ 6 V). 15 and with its emitter through a resistor A ₁₄ voltage. At the base of the transistor Q ₁ are also connected to ground. The collector of the transistor C ₁ and a resistor R _{s anstors Q 5} is connected directly to the emitter of the transistor Q ₆ , which is an input circuit for the connected whose base is directly connected to the first feed pulse generator 70 according to F i G. 1 is connected to the RCB voltage source + 6 V connection. The KoI-ruled impulses form. Finally, the 20 lektor of the transistor Q ₆ is connected to a ß + voltage emitter of the transistor Q ₁ via a source (+ 250V with the polarity shown) and capacitor C ₇ on the one hand and via a half to the cathode of the single beam Color picture tube ladder rectifier D ₂ with its cathode to ground. closed. The video amplifier is used to provide an

The size bypass 50 in FIG. 1 corresponds to the sufficient signal level as well as the correct signal variable resistor R ₃ , which provides the _{end of the resistor A 1} with the collector that is _{reversed from the transistor Q 1} for the control of the color picture tube. The capacitor C ₇ and the like of another transistor Q ₂ connect. The base converter D ₂ , both of which receive the emitter of the transistor _{circuit of this transistor via a resistor A 10} , connect to ground, serve to shift the ground point of this switch mixed with the first supply voltage source + 6 V, a Bias voltage, where the 3 ° around the base-emitter voltage drop of the Tran pulse generator 80 in FIG. 1 to compensate via a terminal RCG sistors Q ₅ , so that the transistors Q ₅ and the series connection of a resistor R ₁₁ and and Q ₆ at lower signal voltages can conduct a capacitor C _{5 of} the base of the transistor Q ₂ , as it would be without z. B. the rectifier D _{2 can} be supplied. The emitter of transistor Q ₂ is would.

directly to the emitter of transistor Q ₁ and 35 die through the connections RCB, RCG and RCR

connected to the emitter of another transistor Q ₃ . in Fig. 3 indicated pulse generators deliver the

The transistor Q ₃ belongs to the pulse generator 60 successively occurring pulses. These pulses according to FIG. 1 to regulate the red signal modulation, multivibrator stages or ring counters and its base, which are obtained via a resistor R _12, operate at the frequency with which the circuit connected to the first supply voltage source + 6 V 40 works (e.g. line- or raster change, the pulses from the pulse generator 60 are frequency), pulse-controlled and fed synchronously by horizontal via a connection RCR and the series connection or vertical scanning signals of the television receiver of a resistor R ₁₃ and a capacitor C ₆ according to the selected deflection frequency. The transistors Q ₁ , Q ₂ and Q ₃ are also nized. The setting via switches S ₁ , S ₂ or S ₃ supplied by the resistor R _s with the respective bias voltage is not only used to set the end of the resistor R _{1 facing away from the transistor Q 4} Tranbunden, so that one or more of the sequential sistor Q ₄ , but also changes the preamble video control signals as an aid after grounding shortening of the picture tube during the outward movement, as can be closed. The switches S ₁ , S ₂ and S ₃ amplifier transistor Q _{4 are} galvanically connected to the picture tubes in FIG. 3 is coupled as a blue, green and red grid switch 50 cathode. As can be seen without further ado, the video signal polarities at the input 51 can be designated and have a different function than that indicated by the numbered switches in FIG. 2. can also be reversed, so that with the corresponding 1

As can be seen without further ado from the drawing, changes in polarity in the circuit of the picture tube

form the resistances i? ₈ to A ₁₃ , the condensate is displayed on its control grid instead of its cathode

gates C ₄ to C ₆ and the transistors Q ₁ to Q ₃ syn- 55 can be controlled.

chronized switch, which the resistors R ₂ , R ₃ The arrangement described here is also suitable

and in general that rheostat that is good for those receiver controls that are used in a

the collector of transistor Q ₃ with the cons-color television receiver are usually present

stood .R ₁ connects when a certain attenuation of As mentioned above, a Helligkeitsregelun:

Red signal modulation is desired, shunt. 60 take place in that one pulses adjustable height

With the polarities shown, the transistors Q ₁ turn on before the Klemrrstufe with the transistor Q ₄

up to Q ₃ only if a positive contrast control can take place at their bases, if:

Directed impulse is applied, so that these transistors, one the luminance inserted before this stage

when they are conductive, their collectors change the bnnach- component of the video signal. A fart

The bare ends of the shunts above the condenser can also be preserved in this way

Connect the C ₇ to ground in an alternating current fashion. The fact that the Fart inserted before the clamping step

adjustable attenuation of the video signal modulation, the differential signal component is changed. Since an Eir

Then by adjusting the variable resistors R ₂ and R ₃ beam picture tube is used, is no Greni

ίο

or application regulation is required other than the bias setting given by the resistance /.

The arrangement according to FIG. 3 has been successfully investigated for its suitability for line-sequential single-beam picture tube color television sets. However, it can also be used with advantage in many cases where an output signal amplitude is to be changed regularly in discrete, individually adjustable steps. For example, other transmission systems come into consideration in which the synchronized pulses of the pulse generator have variable width in order to control the signal amplification remotely or by hand, so that the output signal amplitude can be changed at a regular frequency. In such and other cases, slight changes in the circuitry can be made, for example, instead of the bipolar transistors, the field effect transistors are used for the synchronized switches Q ₁ to Q ₂ . The ring counter or other multivibrator for generating the synchronized pulses can be integrated with these transistors in a single integrated circuit board. Furthermore, with a suitable dimensioning of the resistance Λ and the shunts for blue, green and red, the load on the terminal stage rectifier Z) ₁ can be reduced to such an extent that the emitter follower transistor Qi can be omitted. If the input signal level of the arrangement is sufficiently high, the integrated input amplifier CA 3001 is superfluous, since in the arrangement described it essentially only serves to amplify the video signal. As already mentioned, the arrangement of the output amplifiers Q ₅ and Q _(can be modified so that the picture tube is controlled at the control grid.

The arrangement described above is the preferred embodiment; she can, however can also be modified in other respects without deviating from the essential characteristic that different resistance values can be switched on one after the other in a damping network,

ίο to control the energy supply to the color phosphor elements of a single-beam color picture tube so that differences in the phosphor efficiency are compensated. The arrangement according to FIG. 3 to the effect that one connects the variable resistors for green, blue and red in series between a negative voltage source and the control grid of the picture tube and the video signal either directly or via an amplifier arrangement such as the amplifier with the transistors Q _h and Q _R to the cathode the picture tube couples. With the synchronizing control pulses supplied via the connections RCB, RCG and RCR, the desired resistor can then be switched on one after the other in the manner described, in order to change the DC bias of the picture tube. By selectively setting each of these variable resistances, in this case, exactly as in the case of the arrangement according to FIG. 3, the beam current of the picture tube can be adjusted and thus the resulting light output of one or all of the scanned phosphors can be changed.

For this purpose 2 sheets of drawings

Claims (1)

- r Pa ^ claims: e, ^ ßbldh Pa ^ claims: SJÄe% n, be, ^ 1. A circuit arrangement for influencing the sp-ge "™ _Onschlc" Weißabgldch emgestell, ratio of Wiedergabeintensitat the comparable S j ^spr, "wondere this one Differentialmit the Abtaslbewegung the electron is g.uer _hands" V of the Ro.slrahl