DE2729402A1 - CIRCUIT ARRANGEMENT FOR TEMPERATURE COMPENSATION OF DARK CURRENT CHANGES, PREFERABLY WITH A SENSITIVE AREA OF SEMI-CONDUCTOR MATERIAL PROVIDED FOR IMAGE RECORDING DEVICES IN TELEVISION IMAGE GENERATING SYSTEMS - Google Patents

Description

SCHALTUIiGSANORDmJlKJ FOR TEMPERAiUIlKOiiPElTSATIOH FROM DOHKElSTROMMLIDERUIIQEN VOJi PREFERABLY IiLIT BEAVER FROM SEMI-LEAD FILATERIAL EMP-PIM) LICHEIf PDiCHE VSRSBHENBIT 2I1DAUPN / JMEMI2TEUI IN PERHSEH PICTURE GENERATION PLANTS

The invention is based on a maintenance arrangement for the Tampsraturkonpenaation of dark current changes of preferably with a semiconductor material besides sensitive surfaces provided on sensitive surfaces in close image generation systems.

The known ones with a sensitive plush made of semiconductor material (e.g. silicon) vereohenec picture A 1133-1131Λ2 - Co

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Aufnahir.mittel also have numerous advantages has a major disadvantage, and that the dark atmosphere depends on the tension of the sensitive surface (Target) and depends to a considerable extent on the temperature

The target voltage can be selected by the user within a given range, while the image decomposition system must be operated between the specified temperature limits (ζ · Β. O - 5 ° ^c °).

A small target voltage has a longer memory time (inertia) and a smaller one Dark red while to a greater target tension a shorter reminder time and

heard. a much larger dark atmosphere / in practice the short memory time is very important, which depends on the type and design of the tube Dark Stroin is inevitably associated with it.

The sensitive surface of the image recording medium consists of a plurality of reverse-biased diodes whose reverse current, d »h · the dark storm, from the temperature with depends exponentially to a fairly good approximation

The change in the dark current can be so significant that it is a multiple of the useful signal current achieved * As a result, and because of the automatic The liability rule is reduced

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the amplitude of the useful Vidao signal, or where applicable The video signal completely disappears. If ζ · Β · There is no sensitivity control in the image splitting system provided iat, enlarged

essential

calibrate the amplitude of the output video signals / ζ thereby the image generated by the image display device shows that the quality is deteriorated.

For a known! Compensations proceed η does the video signal from the studio cameras contain a referencing black level at an appropriately determined point » The level restoration stage is matched to the reference black level. The limiter stage must be calibrated in accordance with the characteristic?: independent black level can be set, d, h

the signal / is independent of the dark current changes.

The reference black level is in the video signal installed in this way, on the sensitive surface of the image recording device, to which an optical sight Image is projected, an opaque cover perpendicular to the direction of the line catfish Scanning, in front of the beginning of the lines, is arranged «

The above solution requires a high level of accuracy or, if necessary, special selection rules, around a corresponding centering and tolerances of the deflection coil, the receiving means and the projected optical image

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to be able to.

The division of the position and the on the distraction-related temporal position of the impermeable Coverage requires very precise, stable, i.e. expensive tempier, deflector and Focus activities. In certain cases there are readjustments necessary, which is not permitted with a simple (e.g. industrial) television camera is. It follows from the above that a narrowed line blanking signal deviating from the usual one and a control signal generated by an additional circuit for the level restoration stage necessary is. Another disadvantage is that this solution is used for those with an image intensifier provided receiving devices (e.g. EIC tubes) not applicable it <t, because with light regulation the accelerating voltage of the photocatodo has to be changed, causing a slight distortion of the image and an incorrect one Level restoration comes about

With the invention, the state !.! angel adhering to the technology must be eliminated.

The invention is based on the knowledge that the level voltage of the level restoration and .limiter stage with the help of a temperature-compensating Monitoring unit (of a monitoring element), the control signal temperature of which is characteristic

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. 2729A02

line alt der Dunkels fcroai-Temperatur Kennlinia dos Aufnahnenlttele Ubereins ^ isaat, gaündart cordon can.

The invention is to be explained in more detail below using table games.

Pig _# 1 shows the block diagram as an example

of the invention and ^ Lg ₉ 2 the general picture of an execution case

The essence of the invention-based solution according to Pig · 1 1st * that in dan Vldso-Veraiäricar a Blldzerlsgungsanlage the level voltage of a? Sgelwloderherstall and 33greaserstufβ h with HiLfa dJ.o Toaperatur filled with and with "cutar iTäharung i; 2? Onentlella" characteristic curve nbaprenhend dor nit

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The entrance B23 is JPegalwied

^ is the first picture recording

vsraitirlcta Vldeo-Sl ^ nnl sugefeit · In

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ORIGINAL INSPECTED

the Stuf3 4 becomes dloaoa signal through level restoration and limit processed.

At the output Kl the level recovery rate11- and limiter level 4 appears a compensated Video signal that is free from the dark current changes of the recording by means of

In Pig. 2 is an embodiment the circuit arrangement according to the invention illustrated The temperature sensor of the monitoring unit is a diode D1 through which a 'temperature convergence dor dark current and compensation characteristics is guaranteed.

The input of the temperature compensation probe Stauaraisnalo, i.e. the reverse current of the diode Dl, in the Pagelwiedarhsratell- und Limiter do;? ο 4 will with the help of a simple temperature-stable Stoll switch performed. The setting of the basic value of the compensation and the Pogel voltage is practically independent of each other, although the level adjustment before the stolling takes place »

The temperature-sensitive diode Dl is in Blocking direction switched. The diode Dl has a Pdlckatrom-temperature characteristic curve which is exponential to a good approximation and is placed next to the sensitive surface d ^ 3 image recording means, around a to ensure a good repair run

The Ka-tsaona tension, i.e. the bias of the

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Llodo Dl switched in the reverse direction is first Line through the size of the dark current change, the type of diode and the size of the reverse current change the diode determines * The cathode voltage of the diode Dl can even have a voltage of several hundred volts reach"

The current limiting resistor Rl, whose resistance value is orders of magnitude smaller than the blocking resistance of the diode Dl, is used

for protection purposes

just like the diode D2 / Should there be an overvoltage (e.g. short circuit voltage) at the anode of the diode Dl appear, the resistance Rl

certain Kurzschlusa-Stroin abolßies over the diode D2

be tet and / ka.tne could echädlicho overvoltage, of the field effect Tranoistors Tl occur at the terminal G.

The diode D2 is connected in the reverse direction to the connections G and D of the field effect transistor T1,

But because the reverse voltage of the diode D2 is much smaller than the reverse voltage of the diode D1, the reverse current of the diode D2 is orders of magnitude smaller than the reverse current of the diode D1 ₉ whereby the compensation of the diode D2 is practically not influenced.

Since the above-mentioned overvoltage occurs only with a very low probability, you can

the Strotabbegrenzerjtfiderstand Rl and the protective diode

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D2 at a-ar oi> 'acbjr ^ n • u ^ fiihrunpf.for; n nus dor Circuit wegöölaaa'n «become. In this pail is the anode of the diode W. directly at the connection G connected.

The field effect transistor T1, which is connected as an emitter follower, is operated in a temperature-stable circuit. The temperature-dependent voltage change dee Anachluoaes S dee field effect Tranaistora Tl is in a wide temperature range within several mV · The stability and Arbeitspunlctstroni is by the value of the resistor R2 and the type pt of the field effect transistor Tl l ^o 3tiv "The V7idarstandswert of the potentiometer Pl , the zv; 3ckraäs3ige: rvraise is at most 1 Mohta, plays no role in setting the operating point of the field effect transistor T1, because the voltage generated by the gate current at the potentiometer P1 is negligible. A filter capacitor C1 is connected to the connection G «

As a temperature-dependent generator, the diode D1 generates a voltage on the potentiometer Pl and at connection G This voltage is followed proportionally by the field effect transistor Tl at connection S The voltage of the connection S is the respective, nlso also dependent on the temperature Pe ge! Voltage * The connection S is connected to the level

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Grenzeratufe 4 verbcn.ian,

With the help of the Poteni; are loiters Έ2 may constitute terminal S without modification of the operating point setting dee Feldoffekt-Tranaisijora Tl on a dependent from the image separation unit and the Ruhedunkelatroia level voltage adjusted · The switched in forward-biased diode D3, the Temperaturkompenaationsdiode the Pegelwiederherstell- and limiter 4 "let This Diode can be omitted depending on the version of the circuit In this case the photentiometer P2 is directly connected to the common point d ?? 3 TTidaratgndoa R2 and the potentiometer? 1 angösohloogen *

The Kompansation can be set as follows will be

First of all, the »pausing to rest at the Bijaugstemparatv ve listening. · Then the image decomposition system (Karaora) is placed in a TharooutAt» kept at temperature »and finally the dark disturbance is compensated by adjusting the potentiometer Pl.

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ORIGINAL INSPECTED

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ite

Claims (1)

Claim Circuit arrangement for temperature compensation of dark current changes on image recording means, preferably provided with a sensitive surface made of semiconductor material, in Pernaeh image generation systems, which circuit arrangement is contained in a Vidao circuit, characterized in that the level voltage input of a level restoration and Basrenserntstufe (h) with the output of a Stollechnltung (2) is varburden, and daaa a control unit (1) is connected to one input of the control circuit (2) and a level control unit (3) is connected to the other input of the control circuit (2). 2 * circuit arrangement according to claim 1, characterized in that s θ is the temperature characteristic of the control signal at the output of the monitoring unit (1) with the Dark current-temperature characteristic curve of the receptacle corresponds 3 · Circuit arrangement according to claim 1 or 2 »d α through 5 ο k 0 η η r. jich η st, 709881/1152 ORIGINAL INSPECTED d ι a Li α «üörv / achucgi» unit (1) or that Sensor element zw6ckmäaaigarjreii33 in the receiving means or placed near it let 4 »Circuit arrangement according to one of claims 1, 2, 3» characterized in that a connection of a temperature-sensing semiconductor monitoring element switched in the reverse direction, preferably a diode (Dl), directly or indirectly to the control input (G) of an amplifier stage, expediently sines Faldeffskt -Traneiators (Tl) connected i.at, and the output (S) determining the level voltage of the variable strength stage to a connection of a feedback and / or working point unit stage, preferably to a resistor (R2) and nn the level voltage input of the level restoring and limiter stage (4 ) and the supply voltage connection of the amplifier stage is connected to a supply voltage source, and that a connection of a Kompansationa setting level, preferably 3ln? is potenticmeterea (Pl) ₁ to the control input of the supply stage, preferably a pelde effect Trau3i? itor3 (Tl) > and the other connection of the Koapen-S3tlonaeinfltell3tufe to the common n point represents feedback and / odsr work i ta points ina tails fcuf e and d-3r? tJpj3leiTi3}: all3-i; iifa, zv / sclnnäggiger'.voise of a po- 709881/1152 tentlomatere (P2) and the other connection of the level setting stage, preferably the potentiometer (P2), connected directly or indirectly to the reference point iat _o 5 · Circuit arrangement according to Anapruoh 4t, characterized in that a connection of the temperature-sensing semiconductor monitoring element, preferably the diode (Dl), switched in the reverse direction, via a member of a protection stage, preferably via the resistor (Rl) »to the control input (G) of the amplifier stage , preferably a field-effect transformer (Tl) _{1 is} connected, and that a connection of another element of the protection stage, preferably a connection of a reverse-biased diode, is connected to the control input (G) and the other connection is connected to the supply voltage. 6 «circuit arrangement according to claim 4» characterized in that that the level adjustment stage, preferably that Potentiometer (P2), connected to the reference point via a forward-switched diode (D3) is" 7 «Circuit arrangement according to claim 4» 7 η τ 8 8 1 / ι S 2 dadaroh, in that to the control input stage amplifier is preferably of the field effect Traneistore (Tl), an interference suppression, preferably a capacitor (Cl) is connected · 709881/1152