Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
Title of the Invention
APPAR~'~US ~O~ T~ TR4N~1~IO~i AND
DISTRIBU~IOi~ O~ LIG~T P~DIATIO-l~T
~ield of the Art
The invention rel~tes to high-volta~e conversion
equipment and deals with optical control systems for con-
trollin~ ~eries connected thyristor3, and more pvarticular-
ly, the invention rel~tes to Qpparatus for the trnn~mis-
sion and distribution of light r~diation.
An app~ratus for the trancmission and distribution
of li~lt radiation may be used in converting bridge cir-
cuits of direct current ~ower transmission lines, in sta-
tic co~pens~tors for reactive ~o-~er, as well as in vari-
OU5 vehicles and in the mechanical en~ineering equipment
for illuminating the ~cale~ of instruments and for light
indic~tion of light display boards.
~acl~roud of -the Invention
One of important problems arising in the transmis-
sion of ~adiation from one or several sources and distri-
bution of the r~diation among a number of identical recei-
vers is the provision of uniform distribution of lig~t ra
diation from each sollrce among -the receivers.
~ rith a substantial non-uni~ormity of radiation s~pp-
lied, e.g. to converter~ opticQl control systams ror
controllin~ high-voltage thyristor rectifiers either high
output sources should be used which ensure sufficient ~ ~,
7~
radintlon at the least powerful output of t~Ae a?paratus
for tke tr~nsmis3ion and distribution of lig~t radiation,
or senqitivity of receivers must be imp-oved. ~ot~. facili-
ties result in lower reliabilitJr of systems. .;oreover7
non-uniform glo;:ing of points at a light disnlay board
fol light indication and non-unifol~it~ of illumination
of various in~truments are unfavourable for the perfor-
~nce of an operator.
A po-tential cause of non-uniforrnity of distribu^tion
of radiation resides in optical radiation sources the~-
selves. Non-uniformity of their brightness nnd of the di-
rectional dia~ram of radiation results in difficulties in
the development of optical control systems, systems of
illumination and di~play with distribution of radiation
among a nu~ber of individual outputs and requires special
technical solutions in such systems aimed at eliminatin~
disadv~ntages.
Non-uniformity of source radiation al~o results in
certain difficulties in providing in optical control sys-
terns circuits for radiation control ~ith sampling of a
part of radiation power. T~lese difficulties are due to
the complexity of sarnDling a part of the power from the
total radiation over the whole directional diagram of
each source and frorn the entire useful surface of lumi-
nous body of the source. ~nly in case a part of the total
radiation is ~a~led, the control circuit can give reli-
able indication of changes in parameters of the ~ource or
-- 3
sources of radiation and of respective ch~nge in li~ht
radiatiorl at the outputs of the apparatus.
Known in the art is a starter derice for controlled
rectifiers (cf. US patent ~Jo.3355600, Cl. 3~7-88.5), com~
prising Q plurality of li~ht-sensitivf3 controlled recti-
fiers inserted in control circuits of respective power
rectifiers. The device al50 comprise3 a lig~t source
which is cor~mon for all light-sensitive controlled rectl-
fiers generating and transmitting light energy ~Jhich i9
fed concurrently to all said recti-fiers in the iorm of
light si~nals to ensure firing of the rectifiers. ~ight
radiation is transmitted from the light source to light-
-sensitive rectifiers using light guide~, each rectilier
having its own light guide.
Owin~ to non-tmiformity OI radiation of the light
source in this device, a large scatter OL light energy
fed to each rectifier occurq. In order to ensure firing
o~ rectifiers at mini~.lum energy at one of the light gui-
des, a powerful ~as-dischar~e light source - a flash lamp
is used. Such sources normally consu.-ne high electric po-
wer and are rather unreliable. There is no source radia-
tion control in this ~levice so ~hat adrni~sible level of
lowering of the 30tlrce radiation ener~y during operation
,cannot be assessed, and skipping and misactuations o~ the
source are possible, which i9 very critica~y when such
~ystems are u~ed un powerful converterQ where high relia-
bility of the starter device i~ desirable.
In addition, this device cannot ensure complete uti-
lization of radiation of tne source by the light-sen~iti-
ve controlled rectifier3.
This proble~ wa4 partially 30l~red in a modular 03ti-
cal control 3ystem for controlling thyristor un~t~ (cf.
~R I~ve~tor'~ Certificate No.540337, H 02 P 13/16, 1~72,
Off.Bull., ~o~7, 1~76). The 3ystem comprises radiation
30urces and recelver~ provided with a desired ~edundancy,
Q lencle system, and a hi~h-voltage distributin~ ~iber
li~ht guide of the collector type having end faces of its
~trands coupled to the radiation receivers. Source radia-
tion i3 focus ed by means of an optical system to an in-
put orifice of a light concentrator such as a cone coup-
led to a collector-type light ~uide, which is installed
in a high-voltage thyristor unit 9 and is distributed by
strand3 of the li~ht guide among photocells of each modu-
le of the unit,
Although all radiation from the sources i9 put into
the system and is concentrated at the input of the collec-
tor-type lig~t gruide, owing to non-uniformity of source
radiation the uniformity of distribution of li~ht radia
tion a~ong the outpu-t 3trands of the light ~uide proves
insdequate for reliable operation of the apparatus. This
lowers the efficiency of utilization of radiatlon source3.
The syste~ is also prone to the influence of duqt
deposits on exposed elements of the optical path. The in-
fluence of spurious expo3ure is not eli~inated either.
5 -
s
During installation of the ~ystem relative optic~l ad~ust-
ment of its elements should be made ~ith reference to
both earth potential and potential of the high-voltage
thyri3tor uni-t. In operation, a disruption of adju3tment
of the op-tical system m~y occur u~er the action of vib-
ration3 or mechanical factors.
The system 1~ 3tructuraly hardly suitable for hi~h-
-volta~e thyristor rectifiers made i~ a sealed c~sin~
with the employment of a liquid or ~seous insulating ma-
terial owing to the difficulties in admitting source ra-
diation to the sealed casing by means of a lense system
and complicated adjustment of the system, as well as due
to the possibility o ab~orption of a part of the li~ht
radi~tion with liquid or ~aseou~ insulating material
within the zone of the lense system.
Most 3imilar to the invention i~ an a~paratus for
the transmission and distribu-tion o~ light radiation (cf.
US patent No.3541341, Cl. 250-227), comprising at least
one radiation source ~lavin~ an output optically coupled
to an input of a di~tributing light ~uide throu~h a fi~er
matrix. The output~ of the li~ht ~uides on the receiving
side are coupled~ via light radiation-to-electric signal
converters, to inputs of actuator members.
The ~iber matri~ i3 made in such a ~anner that Laht radi-
atio~ from e~ch source i8 tran3mitted -to each output o-E
the distributing li~h-t guide. The consequence of this is
the possibility for redundRncy of radiation sources and
receivers .
~8~
The apparatu5 also provides for radi3tion sources
con~rol.
Tt should be noted that the ~anufacture of the fiber
r~tri~ is very complicPted, especially for a system h~-
ving a large number of radiation sources and recei-rers,
and the uniformity of di~tribution of li~-ht radiat~on
from each source among the receivers in the ap~aratu3 is
rather 10N due to non-unifoI~ity of radi~ti.on o~ the
sources. I'his result3 in non-uniform illuminQtion of the
end faces of the in~ut stran~s of the matri~ which lowers
the reliability of control Ynd efficiency of utillzation
of radiation sources. ~he ~ource radiation control in
this apparatus i3 based on samplin~ a part of radiation
at the ed~e of the ~irectional diagram ~hich cannot ensu-
re reliable control during operation upon degradation of
the emitter, especially in case a multiple emitter i9
used.
Surnm~ry of the Invention
It is an object of tke invention to provide an appa-
ratus for the transmission and distribution of li~ht 1~-
diation which ensures uni.fo~ distribution of radiation
over the illuminated surface or among pho-tocells of recei-
vers, hence an improved reliability of the receivers.
Another object of the invention is to provide an ap-
paratu9 for -the transmi~sion and distribution of light
radiation ~hich ensures sim~lified methods of assembly
when used in a high-voltage thyriqtor rectifier optical
-- 7 --
75`
control system
Still another object of the invention is
to provide an apparatus for the transmission and
distribution of light radiation wherein the life of
radiation sources is prolonged.
These objects are accomplished by that an
apparatus for the transmission and distribution of
light radiation, comprising at least one source of
light radiation having an output which is optically
coupled to an input of a distributing light guide,
according to the invention, comprises an optical
mixer in the form of a prism which is made with
parameters enabling multiple reflection of light
radiation of each source from the side faces of the
prism which is optically coupled with one end face
to the output of each light radiation source and
with the other end face to the input of the dis-tri-
buting light guide, namely, the prism is elongated
and has a square cross-section.
In case light radiation-to-electric signal
converters are used having their inputs optically
coupled to respective outputs of the distributing
light guide and accommodated in a sealed casing
filled with a liquid or gaseous insulating material,
the prism is preferably installed in the casing, and
the apparatus comprises a rigid light guide in the
form of a rod for optically coupling each light
radiation source to the prism, the cross-sectional
area of the rod being equal to, or smaller than, the
area of the end face of the prism, and the prism is pro-
vided with a guide member installed on its end face fa-
- 8 -
~?'''~
, ` i ,~,.~"
t~
cing the rod, the end of the rod moving along the guide
~ember .:he.~ the rod is installed in the ca~in~.
In ca~e ~ ht I~diation control circuit is used
~hich h3s an input optically eoupled to the output o~ the
light guide for sampli~ a 2art of the radiation, the in-
put of the li~lt ~ide i9 preferably optically coupled to
the end face of the prism fqcing the light radiation
source.
The apparatus Ior the -tr~nsmission and distribution
of li~lt radiation according to the invention is sirnple
in structure and makes it possible to obtain in the prae-
tice high uniforrnity of distribution of radiation from
one or several sources ~mong outputs of the distributlng
light ~uide so as ~o improve the e~ficieney of utili~a-
tion of th~ sources. ~oreover, this makes it pos~ible to
use identical converters at the outputs of the apparatus,
~with a simplified electrical configuration forming sub-
stanti~lly identical electrie signals so as to ensure
high reliabilit~ of optical control system. The apparatus
also ensures identical brightness and illumin~tion of
illurninatecl portions of display boards and panels in dis-
play and illumination systems, respectively.
The inven-tion vlill now be de~cribed with reference
to specific ernbodiments illu~-trated in the ~ecornpanying
drawlng~, in which:
Fi~ure 1 is a diagrammatic view of an app~ratus for
the tr~nsmi~sion and distribution of li~ht radiation ae-
_ 9 _
s
cording to the inventiol~ in a system for illuminating thescales of instrument 3;
~ i~ure 2 is a diagra~matic view of an apparatu9 ~or
the transmi~sion and distrubution of light radiation ac-
cording to the invention in a system for optical control
of a high-voltage thyristor rectifier, having a control
circuit provided with a li~ht ~uide directly connected to
the end face of a prism, and a collector-type light guide
for optically coupling sources to the pri~m;
~ igure 3 is an embodiment of an apparatus for the
transmi~sion and distribution of light radiation accor-
ding to the in~ention, having a prism, a distributing
light guide, and actuator elements enclosed in a sealed
casing, and a control circuit having ~ light ~uide which
i3 optically coupled to the prism by means of a rigid
light guide in the form of a rod.
Detailed Description of the Invention
An apparatu3 for the transmis~ion and di~tribution
of light radiation compri3es at leaqt one source of light
radiation: sources 1, 2 (Fig. 1) in thi~ embodiment, and
an optical miY.er in the form of a pri~m 3 having an end
face optically coupled to the outputs of the sources 1, 2.
The prism 3 i9 made with p~rameters enabling multiple re-
flection of li6ht radiation of the sources ~, 2 from the
side faces of the prism. The other end face of the priqm
3 is coupled to the input of a di~tributing light guide 4
--10 --
7~
It is preferred to use a rectangul~r sq~la-e-section
pri~ m~do of an opticrl glass as the op-tical mixer. ~he
~ide face of the prism may be :~ith or ~Jithout li~ht-insu-
l~ting co~ting. In the latter cRse the surface should ha-
ve mirlimum area of optical contact ~ th a protective ca-
sing (not s~.own), and the inde~ of relraction of th2
prism r~terial ~hould be greater th~n the inde~ of refrac-
tion of the ambient medium~
In this embodiment the pri~m 3 is mRdo of an optical
glass with the inde~ of refraction n=~.52 and with poli-
shed ~aces. The ratio of the edge length of the prism 3
to the length of the base side is 20~ ~en the input
end face of the prism 3 is illuminated with a conical
light be~m ~iith the ~pot diam-ter on the end face 2 mm
and with a~ ~ngle at the vertex 40, independent of the
position of the spot on the input end face, illumination
with non-uniformity of maximum 5~,~ is obtained at the out-
put end f~ce of the prism.
~ his property .~akes it possible to use such prism
for aading lig~t radiations from seve~l sources and for
uniform di3tributl0n of radiation over the illuminated
surface, in particular? for illumina-tin~ the scales of
instrurlent 9 5.
Sources 1, 2 of light radia-tion may comprise inca:-
descent lamps, gas-discharge lamps, light-emitting diodes,
la~ers.
Op'ical coupling of such sources of li~ht radiation
to the e~d f~e of the prism 3 may be effeeted in various
~,~Jay9. Thu3, in this embodiment o~ the apparatus the u~e
i~ made of a lense optical system conventionally sho-~Jn in
biconve~ lenses 6. ~ight flu~ from the ~ources 1, 2 i9
focused by means of the lenses 6 througn an electrically
insulating air grap directly at the input end f~ce of the
prism 3.
Optic~l coupling of the prism 3 to the lnput of the
distributing light guide 4 is effected through their di-
rect contact. Tne light guide 4 and the prism 3 may be
mhde in the form of an integral structure as an element
of the optical system. Their coupling m~y be effected in
any m~nner so ~s to ensure adequate light transmission
and mechanical strength. The number of outputs in the
form of output s~rands of the light guide 4 is chosen de-
pending on specific application, and the length thereof
should be minimum and sufficient for wiring.
Optic~l coupling of the light radiation sourees ~, 2
to the input end face of the prism 3 may be effeeted by
means of a collector-type li~ht guide 7 (Fig. 2) whieh i9
more preferable eompared to the abo~e-described lense op-
tieal system. The ero~s-seetional area of strands of the
light ~lide 7 is ehosen in sueh a manner as to focuse all
radiation from the sourees 1, 2 at their end faee~.
The len~th and design of the light guide 7 should be
chosen in ~uch a manner as to ensure a reliable eleetri-
- 12 -
cal insula~ion of a r.i~h-volt~ge thyristor rectifier 8
;~hich is controlled by mePns of the apparatus accordi~
to the invention. The output end face of the collector
light ~ide 7 may be of round or square section and i9
coupled to the end face of the prism 3 by means of a de-
tachable connector
~ or forming a signal for controlling -the high-volta-
ge thyri3tor 8, the radiation sources 1, ~ used iIl the
apparatus may comprlse gas-discharge lamps, li.ght-emit-
ting diode~, semiconductor lasers such as an injection-
-type gallium arsenide lasers functior.ing on the pUl8e
basis, snd there are provided li~lt radiation-to-electric
signal converter~ 9, The end faces of the output strands
of the ~i~tributing light guide 4 are optically coupled
each to a respective converter 9 which may be built
around photodiode, phototransi~tor or ~hotothyristor. In
such case the cross-~ection~l area of strands of the
light guide ~, the coupling of the strands to the conver-
ters 9, and parameters of lig~t radiation sources 1, 2
~hould be chosen in such a m~nner that the coefficient of
transmission of ligh-t radiation to a sensi.tive area of
each converter 9 be at maximum ~nd that radiation po~1er
at the end faces of the output strands be sufficient for
reliable functioning of the converters 9.
In order to ensure reliable operation of the hlgh-
-voltage thyri~tor rectifier 8, redund~nt converter~ 9
are provided at each module of the rectifier 8.
- 13 -
I~ t~e appara tus for +he t ran~mi~sion and distribu-
tion of light radiation there is plovided ~ circuit ~O
for controllin~ ht radiation. e,g. by radi~tion ?ower,
and a lig~i~ Guide 11 is provided for ~mpl~n~ a part of
the li~ht rsdiation. Output and input of the light Fuide
11 are opticnlly cou~led to an optical wirdow of a p~oto-
receptor at the input of the circuit 10 and -to the output
end face of t}le prism 3, respectively. Optical cou~ling
is effected by means of optical connector3 (not shown).
Sampling a part of light radiation for controlllng
radiation po~;er is effected owing to the backward reflec-
tion of a part of the radiation Irom the output end face
of the prism.
In case the collector li~ht ~uide 7 is used for opti-
cally coupling the sources 1, 2 to the prism 3, the light
guide may comprise a str~nd servinO as the light ~,uide 11
for s~mplin~7 a part of the light radiation.
It follo~s from the propert~`es of the prism 3 that
the circuit tO can ensure a general cGntrol ~ith the use
of one or several sourceY of light radiation. Owing to
the multiple reflection of rsdiation from the side faces
of the prism 3 with forward and bsckw~rd bealns, hig5h de-
gree of proportionality oE radiatio~ ~ampled for radi~-
tion control i5 ensured both with respect to total radia-
tion of one or several sources and -to the radiation at
the output strands of the light ~uide 4. Consequently,
the control circuit 10 may be ad just ed both to the total
- 14 -
raai~tioIl of the source3 and to the radiation from the
output of the apparatus. The la-tter cnpability of the
circuit is ~ue to the uniforr. distribution of the light
radiation among the ou~put strands of the light ~uide 4.
Independent of whPt kind of control (gener~l o~ out-
put) is effected, the control circuit 1~ rem?ins unchan-
~ed and r~y have a config~r~tion ~nown to those skilled
in the art.
In case the high-volta~e thyristor rectifier 8 is
accommod~ted in a sealed casinf,r 12 ( ig. 3~ filled ~Jith a
liquid or gaseous insulatinf,r material such as transformer
oil, the prism 3, distributing ligrht gui~e 4, and conver-
ters g are also installed in the casing 12. Optical coup-
ling ol the light radiation sources 1, 2 to the prism 3
i9 effected by ~eans of a rigid ligh~ ~ide in the form
of ~ rod 13 with the cross-3ectional area equal to, or
omaller tk~n, the area of the input end face of the prism
3. For an optical coupling of the rod 13 to the prism 3
in3talled in the casing 12, the prism 3 has a guide mem-
ber 14 inatalled on the lnput end face thereof, and for
the insertion of the rod 13 into the casing 12, there i3
provided a sealing bushin~ 15. The rod 13 haq a cross-
-section identical ~ith the cross-section of the output
end of the collector light guide 7 but equal to, or smal-
ler than; the cross-section of the prism 3.
It is most preferred to make the guide member 14
with -the im1er working surface in the form of -the 3urface
- 15 -
of truncate~ pyrPmide.
-,~en ~he rod 13 is in~talled, the bushing 1~ ensures
a rough guiding toward the prism 3 so that the end of the
rod will nece3sarlly get into the zone defined by the gui-
de mem~er 14. ;ihen the rod 13 i8 pushed hone, the end of
the rod 13 moves a1on~ the guide member-14 so as to en3u-
re its optical contact with the end face of the prisM 3.
The distributin~ light guide.4, pri~m 3, rod 13, and
converters 9 should be designed for operation ln oil.
In case the rod 13 i9 provided, a part of light radi-
ation iY ~ampled for the control circuit 10 by means o~
the light ~uide 11 by the direct contact of its input end
~vith the end ~ace o* the rod 13.
In operation of the apparatus for the transmission
and di~tribution of light guide, e.g. in a sy~tem for il-
lumination oE the scale~ of instrlments, the light radia-
tion sources ~, 2 (~ig. 1) 3uch as inca-descent l~ps sre
turned on by feeding electric supply thereto. The radia-
tion from the sources 1? 2 i3 focu~ed by means of the op-
tical lense sy3tem in the form of biconvex lenses 6 at
the input end face of the prism 3, High focusing accuracy
i9 not required. Thus, ~;hen the focused radiation spot
t~kes an araa smaller than the area of the end ~ace o~
the prism 3 a considerable unfocusing and displace~.ent o*
the spot over the end face are permitted, provided that
the focused radia-tion i9 within the area of the end face
of the prism 3.
-- 16 --
The li~nt r~diation incident upon the ~rism 3 subjec-
ted to multiple reflection from its side face3 passes
from the input end face toward the output face and ~ets
to the input of the distributin~ ht ~uide 4 ~hich is
in the direct contact ~ith the p~ism 3. Uniform illumin~-
tion from each ~ource 1, ~ is obt ined at the input end
face of the di~trihuting li~ht guide 4 ~ith any non-uni-
formity of radiation by area and an~le at the input end
face of the pI'i~m within the limit~ of the aperture of
the prism 3. Owing to this, e~ual po~,~er of radiation from
each source 1, 2 i9 achieved at the output strands of the
distributin~ light guide 4 with equal cro~-sectional
~rea~ and transmission coefficients of the strands.
This unifo~m rsdiation ~rom ihe output strand3 of
the light guide 4 is fed for illuminhtion of the scales
of instruments 51 each strands illuminating an individual
~cale.
In case the output strands of the light ~uide 4 are
of different length in accordance wi-th desi~n considera-
tions, coefficients of transmission of the 3trands may
by substantially dlfferent. In such case, in order to pro-
vide for identical radiation po~Jer at the output of the
strands of the li~ht ~uide 4, each strand should have the
cro~s-sectional area inversely propor-tional to it 9 coeffi-
cient of` transmission.
~ he apparatus for the tran~mis~ion and dlstribution
of li~ht radiation in a 9ystem for controllin~ a high-
- ,1? -
~ 7
-volt~ge thyristor rectifier functio~s sub3tanti~ similar
ly to the above-de3cribed a?~aratu3.
~ he ~pp~ratu3 is started by electric st~rting pul3e3
hich are fed simultnneously to the in?ut of the sources
1, 2 (Fi~. 1) such as ~emiconductor pul~e la~ers. Laser
radietion is focu3ed at the end faces of~,r~nd~ of the
collector light gu.ide 7 and is fed along the li~h-t guide
7 to the end face of the prism 3. ','/hen the radiation from
the sources 1, 2 pa~3e~ through the ?rism 3 it is psrtly
reflected from the output end face of the prism 3 to~Jqrd
its input end. A part of this reflected radiation gets
into the light guide 11 for ~ampling a part of the light
radiation and is fed to ~he photorece~tor of the control
circuit 10 controlling, e.g. radiation power. A signal
from the control circuit 10 is fed to a control board of
the higk-voltage -thyristor rectifier (not ~ho-~ in the
drawing).
The amount of sampled radiation fed to the control
circui-t 10 depends on the coefficient of reflection of
-the output end face of the prism 3 on the cross-sectional
area of the light Ouide 11 and its coefficisnt of trans-
mission tfor the coated end face the coefficlent of re-
flection i9 ~bout 0.5~o and for uncoated -nd face this co-
efficient i~ about 4~).
Li~ht sigrlals of radiation o-f both sources 1, 2 uni-
formly distributed among the output strands of the light
~ide 4 are fed to the sen3itive areas of the converters
_ ~8 _
9. Li~ht ei ~19 of ra1iation are converted into electric
control pulsDs in the converter 9 to be le~ to the high-
-volta~e th~ristor rectifier 8.
Redunda-lt converter3 9 are ?rovi~ed at each module
of the rectifier ~ ~nd the sensitivity of the converters
9 i9 such ag to ;~or~ no~lally in case of the t~o sources
1, 2 ~ails. This systcm of redundancy of the eources 1, 2
and converters 9 cro~s-redundanc~ makes it possible to
ensure high reliability o-f the high-volta~e thyristor
rectifier optical control sys-tem.
~ he embodiment of the apparatus according to the ln-
vention works along the same line~ as the ystem sho~m in
~i~ 2 and de~cribed above in a system of optical control
of a hi~h-volt~ge th~ristor rectifier enclosed in the se~-
led casing 12 (~ig. 3) filled with a liquid or gsseous
insulating m~terial such as tran3former oil. The only dif-
ference resides in that in operation of the apparatus the
coefficient of tran~mis3ion of the rod 13 should be taken
i~t~ hccount ~ince the rod 13 will somelvhat lolver both ra
diation ~ed to the converters 9 from the li~ht r~diation
sources 1, 2 ~nd radiaiion reflected from -the output end
face of the prism 3 and fed to the control circui-t 10.
In all three above-de~cribed embodiments of the appa-
ratus according to the invention th~ st~lcture and ~qnu-
facture of the op-tical mlxer in -the form of a prism Pre
much ~ir.~pler compared to the ~iber matri~ disclosed in
the prior art. At the 3ame time, better uniformity of
- 19 -
s
light splitting is ach~ eve , unirorm illu.nir~tio~ of the
input end faces of strands of the collector light gu de
is not re~uired, the r2quirements to the sources of li,~ht
r~diation and to their coupling to the li~ht gu-de
strands are lo~er.
As dif~eLred from the concentrator descri~ed in the
analogous art, the optic~l mixer made in the ~ol~ of a
prism ensures ~uaranteed uniformity of splittin~ of light
radiation.
The employment of the apparatus Pccor~lng to the in-
vention makes it possible to i~.prove reliability of opti-
cal con-trol of hi~h-voltage thyrlstor rectifiers o1~in~ to
a necessary deg~ee of redundanc~ achieved by simple means;
eliminate the influence of e~posure and dust deposits on
working surfaces of elements of the o~tical path based on
light-emitting diodes installed in the direct optical con-
tact with the prism, radiation sources, and converter~.
.loreover, the possibility of disruption of adjustment of
the optical path i9 eliminated, first, owing to the above-
-mentioned direct contact between e].ement3 of the optical
path; second, because the lig~t spot can move ~ithin the
input end face of the prlsm; third, ouing to the use of a
mechanical meana (~uide member) for ensuring complete op-
tic~l contact of the rod with the input end race of the
prism.
Reliability of optical control i9 al90 improved
o~ing -to uniform di~tribution of light si~lal among the
- 20 -
7~
cc~ve. er_ and absence of speci~l ad"ust,.ents or the 91'-
..~er.ts of opticsl path ~Jhich, in a~diti~nl Ir~kes it ~ossi-
ble to sir.~pliLy the r~alnten nce o. the apnaratus, especi-
~lly in hi,,~-v~l-ta~,e thyristor rectiIier control syste"ls.
In adc~iti~n, the appara-tu9 has a prolon;,ed ~ervice
li~e vJithout pre-~entive r~ni~ten~nce.
