DE1811022C3 - Device for regulating the color temperature of an object by means of two radiation currents - Google Patents

Description

The invention relates to a device for regulating the color temperature of an object by means of two radiation streams of different spectral composition with radiation modulator in the form of a shutter which has light filters in the radiation-permeable zones, radiation receiver and output stage.

From the specialist literature, for example the book "Temperaturmessage" by Lieneweg, Leipzig 1950, page 104, automatic photocell color pyrometers are known according to the color wedge method, the Via a modulator in the form of a rotating shutter, a radiation receiver and a Phase output stage. The color temperature is determined by measuring the position of the Color wedge determined.

The present invention has for its object to provide a device for controlling the color temperature of an object, which the color temperature of the object with a degree of accuracy of the order of 10 "to IO ~ ⁴ to keep constant in a wide temperature range 'allows using Farbpyrometern .

This is achieved according to the invention by the combination of those characterized in the patent claim Characteristics.

The invention will now be described on the basis of the description of an exemplary embodiment with reference to FIG the drawings explained in more detail. It shows

1 shows the scheme of the device for regulating of color.

F i g. 2 the graphs for the Struhlungsströmc with spectral radiation intensities b _M and /) ₂ , for three positions of the setpoint adjuster in the on F i g. I reproduced facility,

Fi g. 3 the graphs of the impulses at the output of the various elements of the FIG. 1 reproduced Furnishings.

The device for regulating the color temperature of the object according to its radiation consists of

ίο arranged one behind the other: optical input element 1 (Fig. 1), which the object absorbs emitted radiation current; optical setpoint adjuster 2 for specifying the ratio between the radiation currents, aligned for tine certain color temperature, which must be kept constant is by means of the adjusting device 3 with the scale 4; the monochromator 5, which consists of the total radiation fades out the currents of the predetermined spectral composition; the modulator 6 of the Radiant flow; the radiation receiver 7 with the transmitter (photo and thermoelectric or bolometric Transmitter), which converts the radiation currents of a corresponding spectral composition into electrical Convert signals; the amplifier 8 with minimum value limiter, the supply source 9; the phase output stage 10 with terminals 11 from which the control signals are removed.

The control signal passes from the terminals 11 via a connecting line 14 to a device 16, which controls the supply of energy from a source 16 to a furnace heater 17, which has a body 18, the Radiant current is captured by the lens 1, heated.

The operation of the device can be as follows explained.

Let us set the radiation intensity values (brightness values) for two spectral intervals, which the monochromator 5 fades out with effective wavelengths I _x and X ₁ , as Vi and b ₂ .i, ^ obei <j _Xi and r / _2. , The corresponding permeability constants of the setpoint adjuster 2 for the given temperature variable T ₁ .

The signals at the output of the Emp-Tangers 7 corresponding to the above-mentioned radiation intensity variables are designated as U _x = 7L ₁ ^{ViVi un} <l U ₁ = ¹ HjYIb ₂ J, where y, and y _{2 are} coefficients that are determined by the permeability behavior of the monochromator 5 and the spectral sensitivity of the receiver 7 can be determined. By adjusting the setpoint adjuster 2, the temperature Tj, which must be kept constant, is set for intervals with λ and X ₁ , where X _x <X ₁ .

Let us set the transmission coefficients of the amplifier 8 as K ₁ and K ₂ and the voltage on his

55Output as V _x and U ₂ , then U [- K _x U _x and U ₂ = K ₂ U ₂ results.

If the temperature _{variable T x of} the object is equal to the specified temperature (TV = Tjj.soistl /, = U ₂ , U ' _x = U ₂ , where K ₁ = K ₁ ; the voltage variable on

to the output terminals 11 then results in I (J = U [- U ₁ = 0. But since; ■, and y _{2 are} constant, then ² = const. Then '"·' = const, ² '

' ¹ ^ Vj.i Vi

on the other hand is

- f [T _ri ), where T. is the color

tempering door, which is derived from the spectral ratio J ' is determined.

The following applies: 'ti --- · - = / "(T ₁ ,), that is to say that every / -th

Vj.ι

The position of the setpoint adjuster 2 corresponds to the size of the color temperature menu.

If the temperature of the object exceeds the specified value, i.e. if T _x > T ₁ , then the following applies

V,

and the voltage I U < O.

If the temperature of the object is below the specified size, that is, if T _x > T _h then applies

_V _i> V,

V, Vi

and the voltage I U < 0.

The voltage I U is also used to control the heater of the object to be examined, which brings the temperature of the object to the specified size.

The setpoint adjuster 2 consists of a non-selective absorber 13 with location-dependent permeability and a color wedge 12 rigidly connected to it and having a different spectral Permeability for the two radiation currents.

The farther from the tip of the wedge 12 lies the point in which the wedge is traversed by the radiation currents, the more the size of the ratio of the radiation currents transmitted by the absorber changes with the radiation intensities fr ₁ and b 2, so that for all three Positions (I. II and III in Fig. 2) of the currents with respect to the setpoint adjuster 2 the relationship

required dynamic range of the receiver operation Lowie of the electrical circuit and deterioration of the control accuracy.

In graphs I, II and III (Fig. 2) are the .ϊ Radiant currents with the radiation intensities Vi and Vi door the three (I, II and III) from the operator or the program device reproduces the positions of the setpoint adjuster 2 to be closed, the three sizes of the given

ίο Temperature of the control _{correspond to T 1} , T ₁ , and 7 " _ln , where T ₁ <T ₁ , <T _m .

The aforementioned construction of the setpoint adjuster practically ensures the precise setting of the temperature to be controlled with a high degree of accuracy (in the order of magnitude of 10 ~ ³ ~ 10 ~ ⁴ ) and in a fairly wide temperature range.

High sensitivity and accuracy of the setup becomes sufficiently simple both due to the very high stability of the setpoint adjuster 2 as well due to the small impulse behavior of the blocking period to the opening time for the radiation ensures that is generated at the output of the modulator 6 and the radiation receiver 7. How the Modulator 6 and the amplifier 8 with minimum value be ^ enzer is shown with the help of voltage curves in FIG. 3 clarifies. In this case the modulator is 6 as a shutter with openings which allow the radiation to pass through and the radiation does not permeable webs executed.

ίο The pulse ratio is derived from the size of the Bridges

Ratio, = -

γ, * determined. The smaller this one

openings

Ratio to 1, the more effective the minimum value limitation and the higher the Sensitivity of the establishment. This is illustrated by the graphs in FIG. 3 illustrates; included are

20th

4 °

is applicable. But since / 1, </. ₂ . consequently, the increase in the ratio γ corresponds to the increase in the color temperature T _ci . With the rise in temperature, however, the absolute values of the spectral radiation intensities for, and for _{2 increase} very rapidly (approximately in the 5th power) (according to the Wienschen-Planksee law).

This in turn leads to a strong expansion of the voltage pulses at the output of the radiation receiver 7;

Voltage pulses in amplifier 8 with minimum value limiter (U ₁ , - the limitation level after the minimum value);
Voltage pulses after the minimum value limitation and amplification:
the variable constant in the phase output stage 10;

Voltage pulses at the output of the phase output stage 10 when U ₂ > U ₁ .

To do this, 3 sheets of Zciclinuimen

Claims (1)

Claim: Device for regulating the color temperature of an object by means of two radiation currents different spectral composition with radiation modulator in the form of a shutter, which has light fields in the radiation-permeable zones, radiation receiver and Output stage, characterized by the combination of features that are used for setpoint adjustment the required ratio between the radiation currents according to the constant temperature to be maintained in front of the radiation receiver (7) by means of an adjusting device (3) adjustable setpoint adjuster (2) is provided, which consists of a non-selective Absorber (13) with location-dependent permeability and a color wedge rigidly connected to it (12) with a different spectral transmittance for the two radiation currents, so that the size of the ratio of the transmitted radiations according to the color temperature changes that the radiation modulator (6) for a low pulse ratio of blocking duration is designed to the opening time for the radiation and that between the radiation receiver (7) and the output stage (10) directly delivering the control signal in the form of a voltage difference Amplifier (8) is arranged with minimum value limiter.