CA2001758A1 - Apparatus for the simultaneous non-contacting testing of a plurality of points on a test material, as well as the use thereof - Google Patents

Abstract

ABSTRACT
The apparatus comprises at least one light source (3) and a plurality of test channels with in each case one optoelectronic converter (4a, 4b). In the light path between the light source and the converter is provided at least one light channel (5a, 5b) and the test material (1), The light channels are constructed as optical elements for bounding or defining light bundle. A plurality of light channel is juxtaposed in a common casing (6a, 6b) on at least part of the light path. In each light channel can be provided a beam splitter element (12) and together form a single beam splitter (12) removably arranged in the casing. The converters (4a) can be juxtaposed on the same casing as the beam splitter (12) find each is associated with a light channel (5a). Two casigns (6a, 6b) can be provided, the light source (3) in the first casing and the converters (4b) in the second casing (6b) are juxtaposed and associated with in each case one light channel (5a, 5b). At least one part (5b) of each light channel can be arranged in the second casing (6b). The light channel (5a, 5b) can have a common plane of symmetry (7a, 7b) and a casing (6a, 6b) can be constructed in two parts with parts (8a, 9a; 8b, 9b) separable from one another in the plane of symmetry. The light sources (3) and converters (4a, 4b) can be positioned remotely of casing (6a, 6b) and can be connected to the light channels (a) via light guides.

(Fig. 1)

Description

7l15 FO~ ~HF ~L~r~ VS ~)N-OONrACT ~ T~rl~G 0~ A P W RALrl'Y
OF ~O~nS ON ~ L, AS WELL AS IHE USE '~ ~R~

The in~eIltion rel~tes to ~n app~atus for the s~lt~)eous non-contacting~esting of ~ s~u~c~e OL~ m ternAl .inteLf~e of a test material by mean~ of ~lci~ent light or a layer or spatiul portion of the ~est material by means oE back-3~atter~d or ~ack-r~Electr~d tr~lsmitt~ liyht, m whieh the app~r-~tus cuI~)rises at lea5~ one light so~-ce ~n~l a pl~rality of test channel~, each test channel c~npris1ng ~ optoe1ectronic converter and at leaat cne ~ght ch~nne1 arrc~lged 1n th~ ht pa~h bet~een the 1ight source and the ccnverter ~nd in ~hich is pos1tioned a beam sp1itter e1em~lt, e~ch light c}~mne1 i~ ca~st.ructed a~ un optic~1 e~ t ~or ~sf~ling ~ 1ight ~undl~, cn at 1east Ex~rt of the 1ight path 10cate~ within the sane the light channels are juxt~po.~ed in a ccrron casing ~r~ constructed a~ r~cen~e~
passmg throu~h sa~ sing ~n~ the t~t materi~ arranged in the li~ht path bsthe~n ths light qource ~d the ~onverter.

Ths inv~ntion also re1~tes to the u~e of thi~ ~pp~ratu~ for testing a sup$osedly ~nooth or r~gu1arly ~tructured ~urface f~r i~re~u1arities t~eneofr or for testing a light tran~mitting, ~uppos~d1y homogeneous or regularly structured layer for lrreyu1arities or inhcn~geneities thereof and inc1u~ions, or for testing a ~upposedly station~ry ~urface or intern~1 inte~face oE the test mate~ial for position ~hanges to sa1d ~rface, or for testiny a 1ight tran~1tting, ~uppo~e~1y station~ry ~p~ti~1 portion of the test materia1' ~o.r m~vement~ alx1 in pa~ti~u1ar vibrations of lnhomogeneitle~
or incl~lsions ~ the test material, as well ae particles f~o~ting or suspenaed in tl~e latter, or foI~ testing the concentricity ~ a gh~ft for cancen~rici~y e~ors, p~ticul~rly vib~a~lonQ.

T~se ~2 ~ses which ~re in p~ the R~ne as in t}Le l~ser scanne~ in~pec-tion ~yst~n~ (ISIS). The latter r~u~e a r~ech~)ic~lly ~ ted scann~ng syst~n, su~ll as e.~. a rot~tiny m~ polygon, as well as a light collec-devlce, ~uch aa e.y. a light guide ~or gui1.ing the f2c~nning li~t ~e~m to an cptQelestr~ic con~erte~. They are th~ ore e~ive, ~ul)y ~nd ~uscspti~1e to fau1ts, p~rticu ~ rly due to ~eDr, because they do not q?er-ate in a gtatic mann~r. They ul~o do not penl~ the uninterrupted or continu~ test~ng of a f~e n~viny pas~ ~l a ~elative mcvenent o~ a ~urEace of a rotating ~h~ft mc~rin~ past in a re1~tive MW~ment~ The c~nbin~tion cf th~ ~ring pe~t of the te8t m~teri~1 in the longitudinal ct.i~ n1ld Ll!* s~ ]r~ o:E t.l~e l~tt~r ir1 t21e trans~rec~e ~ tion, or the ct~nb~lat.itl of the r~ tlon clrx:~ scannin~ of the t~st ~e~rial glves on the latt~.r a zi~-2~3 test~l surace, whic~ s the max~fn~on spee~ with W]UCII it earl pASS ~sldel t21e LSIS if its enti~ ~ace is to be uninterr-y t~o~tR~ d suc1l as is n~ces~y wheJ~ testin~ t2~e concentricitS~ of a sl~rlEt. 1~1u~, ~tanda~d t~tile webs wit:h a wi~th 01~ ~I rn in the ca~e o~
~he E~ently sta1~ar~l p~s~ye ~pe~ds oE 600 m/min and ~tanda~l rotational spe~s of r~pldly I~t~tin~ ~hafts ~f appI~xm1ately lO m/s are t~o ~st tv ~e tesesd contin~c~lsly ~ith LSI~. Morec~er, ~f not only the concentricity tl1e s~ft, ~1t aL~o its rap~ly sup~ri~ s~ vi~ra~lon~ are to be to~ted, ~u~h a te~t er inspecti~ i~ not possihle with [~IS.

hO-87J3957 di~close~ ~n el~nent~y ~ptoele~tronic testing d~ice, ~hi~h c~nDr~ses a light source ~nd a te~t channel Wi~ll an cptoelectronic con-~ter ~nd a light ch~nel arranged ~n the ligh~ path between the light source ~l~ th~ ccnverter. T~ te~t material is ar~an~d in the lig~t path between th~ h~ m~ n~ h~ ~ r~ . Th~ 1;oh1~ rh~ l h~
WhiC}I 5UpportS a hal~nirroc and ~he ccnverte~ ~d therefor~ a ce~taln thie~ness in order to give t~e necess~ry str~lgth. ~ certain amount ~f sp~ce is al~o requlre~ by ~1e ~lders for the halF~mLr~or and the converter on the light channel, It iB ~d~lttedly obvio~ to atte~pt to ~ss~mble an ~pparatus of the a~Pre-mentioned ~ype fxon those el~m~ntary te ting device~ accor~ing to ~37/03957, l~ tt~sing the s~ne. Hc~ever, this is not possible, because the te~tin~ deviçe~ ~ccordin~ to ~87-03357 cannot be su~fici~tly closely juxt~sed ~l o~ler t~ continuously test a test mate~al rnavitn~
past (relAtive mav~nent, vib:~tion, ro~ation). Even if tlle te~'cin~ de~rices ~re arranged ~n one or two ~tag~ered r~ws, th~ wall thi~hles~ and ~ld~
will take up too much ~ce ~ pelmit the desi~ packing derl~ity of ~
11ght channel~ onse~u~tly the te~ting device~. The de~ d result ou~ only ~ attainable with mc~Il3 than two ai~l~ced rows, which would involve correspond~ y incr~a~ed co~t~.

A test~ng device ~ tlle s~ne type ~s ~IlQC~ kn~ frcm FR-24~1515. Test~ng de~ices lcnawn e.~ f~cm DE-342~43S, GB-20250~1, US-3736065 and L~-5~0~9 c~r~ate acco~ )y to ti~e s~rle p~ ci~1e. I~c~ever, nc~ e vf the afore-n~tion~l d(~ul1erlt~ In~es ~n~ f3L~nce to the ~olution of the aEore-n~ntlon~:l p3c)cin~ ~iensity ~robl~ll. A testincl cle~vice ~lc~n ~rcm SU-666418 Ik~s ~ rc~ CE photc~ c~illC3, ~ut provi~e~ no infonnation a~ to h~ on~ o.r It~o~ S of e~ nel-taL~ te~;~lny (levices o~l ~e hausf~ with a higll pa~killg dcnsity in a c~fiin(3.

ThC pr~bl~n of the pr~sent .~nvcntio~ 3 to prav~de ~n ~ppar~ of the ~for~mentionf~ type wi.th which it i~ le to achif~re ~UC21 a packing de~sity of juxt~posed testirl(3 ~levices ~t a continuou~ or ~minter~upte~
testing or inspection o~ the ~est or inspe~tion materi~ attalnable~
In the case Qf a test material moving pc~st ~relativ~ ~c~ment, vlbraticn, r~tation), it mu3t ~e pos~ble to achieve unLnter~upted testin~ wlth a r~axim~n of two rows of testing devi~es. Fo~ ~le uninterl~pt~ testin~ of stati~lary, flat te~t r~texlal or a supposedly statlonary ~urface o~ ~
internal interf~oe, or a light ~xan~nitting, supposedly stationary ~patial Lortion of the test m~terlal, or f~.r the unlnterIupted testln~ of the con~ntric~ty of a Bh~t, Yeveral rC~'B 0~ test~lg device~, which are ootionally ~e~.ipro&ally st~gered, must be juxtc~posable with t~e necessary pa~king density. This probl~n i~ 801ved ;n th~t the light channel~ h~ve a ccmmon plane of ~ymmetry, the c~sing is constr~¢ted in two past~ with parts sep~r~ble ~ran ~n~
an~ther ln the pl~le of ~ymmet~y, the besn splitter elements ~r~ constructed as parts of a beam ~plittar orming ~ s-ngle subassembly and renov~bly arr~nged in the c~sing, an~
the ~nverte~ Are a~ranyed on the 6~e c~s mg as tl~ be~n ~plitters ln juxtapose~ manner ~nd in each c~se corre~ponding to a li~ht channel.

Preferably the teQt mater~31-~ide ends of ~he lig~t Ghannels are congruent wi~h a ~urfac~ which i~ cons~ruct~1 ~nd ~rranged parallel to a ~urface of the te~t materl~l. The light B~UrCeS aIe p~e~erably fo~ned by ligh~
amitting diodee or l~yex diodeg corre~ ~ ~ing in each ca~e to on~ ht Ghannel, whi~h are po~itioned ~emot~ fr~m the cae~lg ~nd connected vla ligh~ guide~ to the light oha~el~ Ths oonverters a~ p~eferably fo~med by p~otodicdes oorre~onclmg in each c~e to one li~ht channel, which are posi~loned ~te fr~n the ca~ing and are conn~et~d to the llght channelfi &

via l.ight ~i~les, W~liC~I irl tUlll l~an be ~t leflst p.~:~tly ~rranged in at leflst ~rt of a light cl~ el, The ~o pat~ of the cas~)y a~e prefer.qbly prwid~ wlth cor~e~s7pon~ ss~s which, on ~v~ning together the y~rts, ~o~n a l~'~S~; foI~ receivu~ th~ indivictu(~l ~ubass~nbly of thc be~3n splitter.~he l:L921t cl~nn~?ls can cvntain po.l~rizat;ion ancl~or colour filtcr el~ne~ts,.!~hich are c~lstmctecl a~ par~s of a pol~riz~ti~ ~cl/or colour filt~r r~novably ~L~ran~ in the c~sing ~ld Pvnning a s~ngle ~-ubass~nbly a~xt the ~ o part3 o~ the c3s~3y Catl l:x~ p:l~Vi.de~ with corresporld~ng r~esseæ, which orl jo~ ng together the ~arts -tc~et~ler f~lm a recess ~or r~eiv~ny the individual E;ubassonbly o~ t~ iltex. ~ n spl.itte~ el~n~ts ~re pL~fe~bly censtrueted as ~trip m.~L~r elements and tllen in each light channel c~n ~ a~arlged a ~ cnd str~p m~ror element, wh~e ~tr~?s ~e ~n$transmitting ~nd subst~nti~31y corLe~po~ld to t}~ s~rips oP th3 be~sn s~litter elen~ cor~atru~t~d ~s a str.~p m~r el~nent. ~he ~tri~ m~rror el~nentS are co~t~ct~ ~ e c~a ~CsT~itr~ ttv~ ~tr~ mi~
f~lminy a s$ngle subaa~elnbly an~ vably ~ the cacing. Pr~f e~bly each ligh'c c}~nnel contains ~ s~cond 1~ plitter el~n~nt. The sec~ld bean splitter el~T~ents ~ construct~ a~ parts c~f a second ~e~
~plitter fo~ning an individual ~ub~ss~nbly and r~ab~y arran~ed in the c:asing. In each csse a seeond con~rerte~ sitioned ~ppo~ite to the ~cGnd beam splitt~r element m the same way ~s the first conv~rter is positi~ned ~cing ths ~irst beam ~plitter el~nent, AS a re~lt oP the lnv~2tive arr~l~en~nt o~ the light ch~nnel~ in juxta-po ~d manner ~n A commcn ca~in~, ~he pack.ing densi~y oE the j~xt~po8ed te~tin~ dev~ce~ can be ircrea~ed to such an extent th~2t it i~ possible to attain an unlnteI~upte~ testmg or in~pection o~ the test materi~l movin~ ~
p~2s~ (ral~tiv~ mcvenent, vibr~tion, r~t~2t1on3 with ~2 maxiMun o~ two row~
of li~ht channel~. ~s a`funct~on o~ the collim~tion achiev~d ~n the light ~hannels, it is ~ten possible to schl~te an uninte¢rupted te~ting o~ th~
te6t m~tex.ial with ~ ~inyle xow o~ lig~t ~hannels. Thus, the inventive ~pparatu~ tatic, ~ma~l, robu~t ~nd inexpensive t~ n~nu~acture, 8~ that ~t can be ~sed in pl~ce o~ LSIS.

T~rough repl~cin~ LSIS by the inventive sppAr~tu~ in ths ca~e bf uninter~ ~
IUptel tes~ing o~ th~ test m~terial, its passage ~peed (rel~ive mc~ment, vibr~tion, rotation) can be si~nifican~y increased eonpared with what 7 5 ~;3J

-- S --~L!n3 ~}ee~ t~J-L-~.C~ ~chievabl~ use the ~scl~ievable ~ it ~or the pass~ge, vibral~ or n~ati~ al spe~rl of the l:est mal:erial i~ nc~ only ~ete~n~-~ ~y the optoeleetmni~ ~ign~l proeessirlg and the pa.5Eir3ge ~peed cc~n e.g. be 1000 m~nlm and ~le vibrAtion~l vr rot~tion~l speed can e.~
nP~ th~m lO m/s. I.~n1ike in the ca~ of I51S, the length of the rcx~ of light cl~-ne].s iE unlimitel :~n the inventive apparatu~;, so that in the case o~ the latter t:her~ is ~lso no ~estriction to the si~e of the te~t m~ter~l mov~ng past ~ lt ~n e.g. }~ve a width of 10 m. Even in the ~ase of ~uch a wide and rapi~ly p~s;ing or ~a~e and rapi~ly vibratln~ or r~tating testlna~L~l, the non~lal de~e~tl~) ~an~e Or 10 to 500 ~
re~ulting ~r~n the me~sur my principle in the e~se of ~ ~patial errDr resolutlon o~ 2.5 n~ is 6till attainable and it is pos~ible to dete~t 5 um holes, In the ca~e of constructing the inventive app~ratus with a plur~lity o~llght ~ources, which in ~ch c~e corre~pond to a light channel and which are formed f~om llght emittin~ dio~a~ or laser diodes, if a l~yht &ource fail~, only cne channel and not the complete apparatus f~ils, 60 th~t during ~he ~reahdch~ only a very ~nall part of the test m~teri~l rem~ns unte.~t~d~

Due to ~he small d~mensions o~ the app~ratus accolding to the inv~nti~n, lt c~n be housed in cfls~g~ under re~tricted spat~al cundition~. e.g. in v~uum b~ of v~pour d~pos~tion ~y~tems, spraying sy~tems and the like, w~ich is not posqi~le Wi~l LSI5 due to the dlmen~ions ~f -~uch syst~n~ ~u~
to the small d~nen~ions oE th~ inventive apparatus, it eAn also be housea withln pipes and sections, ~hich i~ not p~ible wi~h LSI$ due to the dimensions of su~h sy~tYms.

Under th~se oircun~t~nces ~nd due to ~hese adv~ntage~, th~ inv~tive ~ppa~atus c~n be u~d for testing a s~pposedly ~tationa~y surface or internal interface oP the te~ m~terial ~or po~itional ch3n~es thereo~, which are e.g~ oaused ~y movem~nt, ~ fltion, e~pan~on, shr~nkage, gro~th, deposits, etc., ~r for testing the cc~entricity 0~ ~ ~hs~t for concen-tricity error~, part.icularly vibrations, ~ptiorlally ag a ~unction oP the ~otation~l ~peed of the ~ft, or for testin~ a light tran~mitting, su~posedly sta~ional~r l~yer V~ a lig~t tran~mittlng, ~uppo~edly ~t~tionary L 7~.3 spatial portioll oE tl~e tbst mat~t~ l for moYHne~lts ~d ~n p~ ul~r vl~rati.olls ~F lrll~ml;x3~ne1ti~s or ~lclllYiolls ~- th~ te~t m~3teri~1, a~ well p~rticler ~uspend~ Gr flo~tu~g in the te~t Inateri~l]..

~ n~le~ o~ ~uch u~es a~ COl~ di~ks ar2d gl~ss pr~ cts su~h a~ mir~r~3, dis~;s c~nd pip~3s, in the s~nifini~h~ or ~i~ish~ 6~ e. ~r~ , ie has not hiths~rto been ~ppro?r1ate for p~ e rea~s to te~t c~(pact dis1~ both ~e~ore and ~fter coatiny the bl~nk, so t~t it was ne~e~s~ry to ;~ke do with testing follc~ng C:Oflti313, The inventive appar~tus makes it po~sible to carIy out both te~ts ~1 ~duce costs. Other e~ le~ relate to te~3t~
on the behaviour of mechanical ~t~ such ~ a~craft ~ing~, ~r t~e advance of plysical p~esses, such as e~ sicn, sh~in1~e, condensation, p~ipieatlon, evcqpor~tion, phase c~ge6, c~stallization, polarization changes oE areas, sl~ chaTical re~ctions, ~uch a~ co~ion or rapid ch~nical r~actions, such a~ explos~ons, biologi~;:al proces~ uch ~s the g ~ th of microbiolo~ical c~ltures, pl~nt~, etc. or tests on stationary or flo~in~ gase~ or liaUi~8, ~mulsion~, ~uspensions, etc., e.g. with r~spect to oh~ni~al ef~ect~, su~l~ a~ col~1r, polOEi7.Htion br d~ity ch~nges, h~ dynamic or ~coustic e~ects, fo~mation o v~pcu~ bubbles, flow rate~, ~ontent of entr~in~d p~rticle~ o~ bubble~t atc.

It is stress~d that ~cceler~meters and ~esistan~e strain yau~es oE the conv~ntional type require c~ecting wires, whereas tha invent~e appar~t~s cperates in non-cont~tin~ m~ler.

Acccrding to a Yariant of ~he ~e, it 1~ pos~ible to u~e on ona slde o~ tha test ma~erial an apparatu~ ~or te&ting by mean~ o~ ~nci~en~ light or b~ck-sca~tered trdn~mi~te~ liyht and on the other side ~f ~he test materlal a retrvreflec~or ~or the tr~nsmitted l~gh~. In anot~er ~$~ var~ant it i8 possible to pro~ide on one ~id~ of ~he test matex~al an apparatu~ $or testin~ by m~ans o incident lig~t or back-soatte~ed tran6nitted lig~t and on ~he oeher ~ide thereof an ~bsorber for th~ tran~nit-te~ liyht.

~s, the ~ppaxatus ~coording to the inYention e~n te~t in different ways different types v~ ~k~egularitie~, inhomo~enelties, inclu8ions and m~vqment~
~nd supply e espcn~ingly dif~erent~ted results ena~ling ~onc~usi4ns t~

7~j~J

b~ dr~n regal~lng their c~u4es, ~no"g tl)e use~ of th~ appaLat:us accor~in~3 to the im~ention over and beyond those all~x3y merltioned, re~e~nce iQ e.g. m~le to the test~g of ~ oat~
or ~netal-coated or colwr~co~t~ polymer foils *nd fi~ns, metallic or met~l~
coate~l objects such as ccng?act disks, unco~t~, coat~ or coloured papsr in web or sh~et ~o~n, unco~ted or metal-coated or col~-coa~ lat ~lass, unc~ated or coat~d textile a~ticles Qn . I~aces or c~t~ defects ~uch as irregul~srities, deposits, scratohe~, duril: pArtlcles, holes, cavitie~, inclu~;ion~Q, colcur or optlcal di~f~rences, rough points, ~rocve~, etc., a~;
~ell ~5 st m ctural var.t~tions ~e~a~d~ng the crossl~nking or pattern or printin~ quality.

In an exampllfi~ ccn~tructi~l o~ ~n inventive appal-a~us int~ded ~or testing pa~sing ~Yebs with a width of 250 mm, in both c~sing~ there are g6 light ch~nnels with a cros~ ction of ~.54 x 2.54 ~n in t~Yo ~taggered rcw~
of ln each case 48 light ~hAnnel~

In another ex~mplified con~t~u~tion of an invent~v~ apparatu~ u~ed ~or testin~ compact ~i~X~ wi~h a ~ibne~er of 130 mn at ~ rate of max R seconds pe~ plate, in one or two ca~ing3 ~re provlded 32 li~ht ch~lQls with a cro~s-section of 2.54 x 2.54 mn in th~o staggered ~5 c~E in e~h case 16 light charulels. In both ~ s, ~ully refle~ting æur~aceæ can be te~tsd in th~ reflection mode.

F~r testir~g partl~r reflecting s~rfaces o~ transpa:rent tes~ material, ~t ~s ~ossible to pl~re ,~ black light ~b-Qor~r under l:lle s~e. F~r te~ting the interior of t~ansparent or li~ht-tran~rnitting test material a m~r ~n ~e placed under the seme and when u~lng a half~ni~Tor the partly re~lecting ~faces and the intQXior can be 8imultar~ sly te~ted.

In another ex6~ fi~1 c~tmction O;e an inventive ~pp~ratu~ ~ntendsd ~o~
te~ting the concentricity ~ a s~ t witl~ ~ length of 250 mn, the l:wo ~as~ngs conta~ 9~ ligh~ channels with a cr~q-section of 2.54 x ~.54 mT
in two ~taggere~ ~5 of~ in each ca~e 48 light channel~. In the ~a~e of a n~r ~oth su~Ea~le, test~ng c~n taks place in the reflection mode, Tll ttnoLS~er e.~npl~fi~cl ool-lstl~lctiorl c~f an inverltive ~palcttur-t uae~ for te5tin~ tr~tS~Clrellt l:i(~til.l or gas ln a pipe ~ith ~3n ~nspection gl~lss with a width of loo Inn, ir) one or two C~ln9E; are p~ovic~ 40 light ~:~rmels ~l th ,~ rmc~ e,~ D~ a_v ~ A. ~J~ t~ Lvl o~-h c~se 20 li~ht chLtru~els. F~r t~'liB p~pose testing can b~ c~rried ou'c in i:h~
~ran~tnitted light In~xle with a llght ~our~e-side casing and a ste&ond c:on~,~e:rter-side cat~ g or on one ~ide in the inc:iden~ lighk n~de wi~h ~t facin~ mirrOr.

The ir.lventlon is de6crib~:1 ~n greater d~tail here~lafter relative to non-l~rtit~ttive etil~odi~nts and wit~ ~fererltca to tlle ~ttta~led drawir~tgs, wherein 8hc~:

F~g. 1 A d~agr~rtlrt~ttic ~i~e v.i~w of a cons~i~ctiOn 0:~ sn ioventi~e apparatuict w~th a 11ght source-~tlde, t~o-part c~tsin~ and a se~or~, t~7o-part C~t6inE~ ea~ case for 6 light: chartne1s~

Fig. 2 A diflyr~m~atic fIont view of the light 80 lrce-side ca~lrtg p~
of the apparat~t~ tn 1:he left irit fig~ 1.

Fig. 3 A ~ tgra mati~ reL~r view o~ the ll~hl: sollrce-si~le ca~ir.tg of the ap~ratuEt of ~ig. 1.

Flg. 4 A dietgr~nnati~ riew of the Fte~ond castiny o~ the ~ t of f ig . 1.

Fi~. 5 A d~agrarlTatic view fr~n belc~ of the l~ht sc~urce~ le ca~
o~ the ~pparatus of fi~. 1.

Fig. 6 A di~granrnat1c plan view o~ the ~ecend ~asin~ of the aE~ra~u~
o~ f~g. 1.

Fig. 7 A diagr~matic rear vie~ of the cas~g p~rt ~n to th* left in fig. 1 of the li~ht ~aurce-s~:le e~ng o~ the ~paratu~
thereo~, Fiy. 8 A d~r~ tic front view of the ca~ p~rt of the ~e¢ond c~:Lng 6ha~l to the right in f~g. 1.

3 ~ .

~ig, g A di~-amnatic view o~ the o~lti.cally esselltla~ nt~ o~ ~n inventive a~paratu~ in a UBe ~or testincJ a ~ac~ or an in-te~n~l ~u)t~rf~ce of the te~t m~teri~l ~y meanY o~ light, or a la;~e~ or ~ ~;patlal portion of th~ te~;t mater.tal ~ me~s of back-scat~e~e~ trarl~nitted li.ght.

Fi~ 10 A diagr~nmatic view c>~ the optic~ly ess~ntial el~nents of an inventive appparatus in a u~;e for testing a l~yer ~ a portlon of tl~e test m~t~rial by mean~ transmitt~ light.

~iy. 11 A di~ nnati~ view of the optically ~ssenti~l el~nents of an apparatus b~sed on tl~t o~ f~g. 1 for testin~ ~ curved te~
material, in whlch light ~uides and a ~ngle light ~ourt:e us~d, Fig. 12 A diaçlr~rrmati~ vie~ of the optlc~ly e~Qenti~l el~nent~ of an apparatus deriv~d fr~m that of P~. 1 for test~y a ~ved test materl~l, in which cert~ln opt~l elements h~e been mc~v~ to the ~ecand c~ing.

~ig. 13 A d~gr~mati~ plan vi~w o~ tho second ca~ing of t~e appa~at~
of fiy. 1 in the ~as~ ~ a constn~ction wit~l two recip~c~lly di~placed r~Y o~ test c els, Fig. ~ of an invent~ve aEpa~a~uY in a d~agr~nnatic ~i~e view. This flpparatus i~ interx~ o~ ~he ~nn.llt~ nosl~co~tactlng te~tin~ of poiJ~t~ o~ A surface or spati~l portlon ~ a test materi~l 1 and ~unctions aceording to the 8ane principle a8 the ~paratus hna~n f~n t~a7~03~57 and Gcns~uerltly ref~ence sh~ld be ma~e to the latt~r for further det~ s.

T2~ appara~ls c~?ri3es e~x test char~els 2 with which ~r~ as~wiated in each case one light ~ e ~, which is cen~tructed as a li~h'c emitting diode, a~d thr~e optoelectr~.lc C:CInVOEte~3 4ar 4b arx~ ~c. ~n the light path ~etween th~ light sou~e 3 an~ the ca~verter~ 4a ~r~l 4c a light channel 5a ~s arran~od in each te~t c:~el. In the light path be~eeJn light s~urce 3 and con~rer~c;r ~ is prwlded a ~wo-part light channel 5a, 5~, 75~ !

rrhe te~.t mate~ p~iti~)f~ th,~ light path between llght cource 3 an~ c~verte~ 4a, ~b or 4c, Strictly 6pel~ing the light ch~nnel 5~ betwe~n liyht ~c~rce ~ .3~1 con~erter 4a i8 al~o ~1 a two-p~rt fonn, becAu3e the lig1~t fi~stly passes t1~rou~h it fr~ light sc~ce 3 to te~t rnat~ri~ nd th~n ~er part of its length a~in fxcm t~3st ~aterlal 1 to eon~erter 4b, Th~ function o~ light ch~lel 5a, 5b is to l~nit the liyht bun~le oF thellght p~ss mg fr~n light ~olr~e 3 to testrnaterl1l l, i.e. to keep the divel~ence between individu~ ht be3m~ of the llght bt~r~le ~maller th~n a predeternine~ le~ In t~s 6~nse llght cha~el 5a, Sb is u1 optical elernent.

In the repIes~nt~d constructlon this ~ptlcal el~nent is constructe~ as a paralleleplpe~ic c~vity, whioh i~ provided in casing 6a~ 6b and in the represented c~n~truction 8iX such cavitie~ ~re juxt~posel in in each case cne c~nnon first casing 6a o~ ~e~ond ca~in~ 6b.

As sho~n, casing 6a, 6b c~n ~e construct~d in two-part f~n, in onder tofacllitate the m~nuE~ure of the li~ht channels Sa, 5b, e.g. by milling.
This two-part fonm o~ the e~s mg i~ vi8ible in fiys~ 5 and 6, fig. 5 being a diagrannatic view fr~n ~el~ the light source-~ide c~ing 6a ~nd fig. 6 ~ diagr~lmatic plan view of the second cas~g 6b. Figs. 1 and 5 ~how th~
interface 7~ be~ween the tWQ casing parts 8a, 9a o~ ca~ing 6a, whilst 1 ~nd 6 shcw the interface 7b between the ~wo ce~ parts 8b, 9b of ca~ing 6b. Figs, 5 ~nd ~ ~how the construetion of the li~ht channels 5a, 5b on the qu~d~angular ~oss-~ection of tha p~rallel~pipedic c~vities 5e, 5b, whereo~ 5iX ar~ ~uxtapossd ~nd i~entical to one another, ~o th~t when de~cribing the test channels hereinafter (i~e. everything llnk~d with an indiv~ual light channel), only one of the~e need be de6cribed. The in~icA~ed intex~ace 7~ or 7b a~vantagecu~ly fo~ms a plane of syrnnet~y of the p~rticuLAr light chennel 5a, 5b.

.~bave the test mater.i~ f ~ . 1 shcws a ConBtruction 10 of the invent~e ~pparatus used for testing the uppe~ sur~ace 11 of test materi~l 1 by ~e~n~
of inc~lent light ox the car~lete layer thlck~ss, or the c~lete thlcl~ess of the spatial portion o~ the test materi~l 1 by mean~ of back-scattered Z~

tr~l~nitt~ ht. Th3 parallel~pip~ic eavity 5a passes th~c~gh cct~tg ~a. ~rhe li~ht emitt~lg dio~e 3 i8 inserted. thereln at it~ end. At lts othex el~, it t~nninates wi~ the o~ting Sa visibl& in fig. 5 facin~ the surface 11 of test materi~l 1.

A bec~m splitter el~nent 12 con~ ~tcted ~s A h~f~mirror ie arranged ~t an angle o 45 to ti~ longl~tdinal axi~ of c~ity 5a therein, an oLder to deEle~t the ligh~ refle~ed or ~ack-scatt~xed 4y test materi~1 1 to ths cptoelectronlc co.t~verter 4a. The be~n splitter eleme~t 12 .t8 con~tlu~t~d as a sent$reflecting glac~ plate, whlch extends in one piece, i~e. a~ ~
6ingle sub~s~enbly oY~r the ~ix light channel~ Sa ~nd the ent~re w;~th of ca~ing 6a. This glass pl~te 1~ ls inserted in corresponding slots 13 or 14 of e~sin~ p~rt S~ or ~a~ the slOes 13 and 14 to~ether forming a reee~s for ~eeeiving the ~la~ pl~te 12 when c~sing part~ 8a ~nd ~a are joined ts~ether. The slot 13 in easing part 8a i~ mora partic~larly vi~lbls in fi~. 7, as well ~s the half of c~vity ~a loeated in casing par~ 8a. Thc 510t 14 in cas~ng part ~a i5 more particul~ly visible in ~ , as we~l as the hal~ of c~vlty 5a lce~ted in e~sing part 9~, It is clear that the aforenentioned divid m g into two of the easing 6a into parts 8a, 9a ~ d litates signlf~cantly the man~fa~tu~e o~ slot~ 13, 14 ~nd that, i nece~a~y, the glas~ pla~e 12 can be r~nov~d fron casing 6a by 81i~in~ out of xlot~ 13, 1~.

A light p~ e 15 for each te~t channel ~s pr~vided in c~sing pa~t 9~
~figs. 1 ~nd 2~ and lea~s frcm c~vity Sa to the out~lde. The light pa~age 15 enables the light of li~ht ~mitting diode deflecte~ by gl~s plat~ 12 to pass to the out~;fle ~nd i~ not ~catteled back ~y the wall o~ c~vlty Sa to the glas8 plate~ For ~xample, the unae~i~e~ ht o~ liyht enitting diode 3 deflected by the glYq~ plate 12 can pa88 through the l~ght pa~eag~
15 to ~ light absor~er~ It ~ould also be ~os~ble to con6truct the w~ll ~.~ o~ C~ ~ 1'9~ ~o~g ~
emitting diode 3 de~lected by ~l~s3 plate 12 ~eturn~ to ~he lattex and through t~e la~ter to photcdicd~ 4~.
cn5ing p~rt 8a ha~ a light passage 1~ ~or each te~t c}~nnel tfigs. 1 ~n~ 7), wl~ic~l lec~:ls f~ n the ca~l1ty 5tl to tll~ optoelectL~nic converter 4a. The liql~t pas3a~1e 16 pellnit~ the liy~ cc~ning fr~n the te.st materl~
rieflectecl by the c31..~ys plate to reach th~ optoelectr~nic c~lverter 4a. The latter ls an apE)l~ximately qu~rlranc~ lar photodicde, whose photosenriitive side is counter~ k ~n a slot 17 provi~ecl for tllls p~lrpose in casing part 8a (:Eiys. 1, 3 ~r-d 5). ~ prir~ted circui~ 18 ~i~. 1) carries the electronic c~it for ~lle photcdiode 4a a~ supp~rt~d by me~ of carr~e~ el~ents 1~, 20 on c~siny p~t B~l. The P~sten~g el~nents which can be UBed, such a~ 13CI~b and tapholes are not shawn. By means o~ a cc~estor 21~, 21b th~ prlnt~l ci~it bx~Ld 1~ ls elec h ically connected to a plu~-in ~onnection 22, whlch can recei~e a cable conn~ction, In tu~n, the light e~ltting di~de 3 i~ a~ran~ed on a pr m tel circuit ~oard 23, which ~R suppo~ted in ~boves 24 or 25 o ~a~ing p~rts Ba or 9a (fig~. 1, 2 and 7). The pr m t~ circuit bcaxd 23 alRo carries a pl~g-in eonneatlon 26, which can receive a cable connection.

A~ i~ apparent, on the one 2~nd the eix light enlitt m g dio~e~ 3 and on the other the six photodiodes 4a can be arran~ed in ~uxt~osed manner on the s~e casing ~ as t~e be~m ~plitter 12 and in each c~e one light amit~in~
dio~e 3 and one photodiode 4a is associatQd with e~ch light channel 5~, whllst the bean ~plltter 12 i6 cunmon to ~U six ll~ht channel8 5~

~r testing th~ uEper ~ ace ll of te~t m~terial 1 by meana ~ incident llght, i~ is possible t~ diLe~tl~ u~e the de~cribed ~pparatu~ 10. In ~ach te~t channel th9 photodlode 4a l~ceives t~e porti~n of the light which i~
re~lected or ~catte~ back ~f the te~t mate~ nd which p~sses ~rc n light emitting diode 3 vi~ l~ht ch~nnel 521 to te5t mate~ial l, 60 that l:he latter i8 located in the light ~?ath ~etween li~ht ~ource 3 and conv~rter 4a.
f ~he te~t mater3~1 iR trar~spnrent, it i8 pos~ible to ~rrang~ it (l.e. on the other side oÇ th~ test materi~l 1 coTpared with the ~pp~ratu~
10) an optical el~nent 20a, w~ch ~or tast~ng tha complete layer thickne~
of test m~terial 1 by means o~ bacx-s~atterbd tran~mitted li~ht can be a lighl: ab~orber, or ~or testing th~ entire layer or the entire thickne~ o~
the ~patial portion of the te~t material 1 by means of t~an~mitted li~h~
a mirror~ The optically es~enti~l el~ne~lt~ oE ~his ~rang~nent are d~agr~-matica~ly shvwn in ~ig. g, the cptical el~ent 28 beLn~ ~hown ~5 a l~ht ~17~3 absorber Ar~ th~ llght be~n is desigllated 3a.

~1 anoth r variant oE ~his con3t~lction ~he bean splitter elenent 12 13 censtlucte~ a~ a stlip m~r~.~or el~nent, ~o th~t, ~g ~lown Prom w~-B7/039S7, a str~aked effect i~ obtaine~.

Fig. 1 sh~ws bel~Y the test mate~i~1 1 thAt pal-t ~9 oE the inventive apparatus, ~Yhich i assocl~ted wi~h the ~esting of a l~yer or a ~patial portion of the test materihl 1 by mean6 of tran0nitted light. The second part 5b of th~ two-p~rt 1ight charulel Sa, 5b is c~onst~ cted a8 ~
p3rallelepipedic cavity 5b and passes thrcu~h the sec~-d ca~ng 6b.

At one end of the parallelepipedic cavity Sb is arranged a second opto-elec~ronic eonverter 4b which, like ~he optoelectLvnlc ocn~ter 4a, i~ ~n ~pprvxim~tely qu~drangular pho~c~ode, who~e pho~osensitiv~ 6ide i~ ca~ter-sunk in a Ylot 30 ~ig5, 1, 4 and 8) provlded for thls purpo~e in the t~o casing parts 8b and ~b, A printe~ circult bcard 31 (flg, 1) carries ths electronic GirCUit for the photod~od~ 4b and $~ ~upported by mean~ of ~
carrier element 32 on casing part ~b, the fastening elements u~able such as sorews and tqpholes not ~ein~ shown. ~y me~ns of a connector 33a, 33b the printed circ~lit bcar~ 31 i~ electrically connected to a plug~in ct~on 34, ~,Yh:;oh c~n rcocl~c ;~ o;~b:Lc conn~e.tlon .

At its ot~e~ en~ the p~rallelepipedic cavity 5b tenninates with the opening 5b vis~ble in ~lg. ~ opposit~ to the lc~er ~rface 35 of te6t material 1.

The ~pparatu~ accordiny ~o the invention comprise~ two casin~s 6a, 6b and ~or each light c~u~el t~e light emitting diode 3 $s in the fir3t ca~ing 6a and tl~e photo~iod~ 4b in the second casing 6b ln ~uxtaposed manner and a~n~d co~respond~ng to a li~ht channel. In the construction ~ in fig. 1 a p~rt 5b o~ e~ch ligllt cl~nnel iR arrAnged ir the sec~nd ca~ing ~.

In each test channel the ph~todi~de 4b recelves the light port~on tran~-mitt~d by the test materi~l 1 ~d this passes fran the li~ht ~nitting diode 3, via the light channel 5a to the te~t materlal 1 a~d fmn there v~ li~ht channel 5b to photcdio~e 4b. Thus, the te~t rnateri~ ated in the ~ 3~7~J

lig}~t p~th b~tween llght ~our~e 3 alx~ cooverter 4b. The optically e.~enti~l el~n~nt~ of tlli~; tlrr~l~]ernent arc di.~yr~nnatical.ly rep~erlte~l ln fig. 10.
In the llitherto describ~ co~l~truction the te~t materlal 1 is substantially plana~ ~ld th~ t~3st m~te~ial.-~ide endB ot.~ the li~ht cl~nnels 5a, 5b a~e congment with a plane parallel to the test Inaterial 1. Ii~ the test mate~ial has a pr~eterrn~ned r~ular cur~atll~e, e.g. i~ i~ i3 const~ct~d as ~ glass ~be, the appalatus c~n be ~pte~ l:o the shape o the teYt m~terial, ln thflt the test mat~3rial-si~ endY of the li~ht c~nnels 58, Sb are congruent with a sur~ce, which i~ construct~l ~nd positloned parallel to the su~E~ce of the test materl~l. In the case of a cylindric~lly or spherically curve~ test m~terial th~ fig~. 2, 3 and 7 th~ l~wer horlzon~l lin~ of the drawing would be an are lnstéad o a straight line.
In the C~se of a d;~ferently curved ~h~pe of the te~t ma~erl~l, the test materlal-side end~ oP the light ahannelb 5~, 5b would be congLuent with s~r~ace correspondingly ddapted to the test mate~i~l surf~ce, 80 as to be parallel thereto. The optlcally e~s~ntisl el~ment~ of sueh a construction are di~gr~nnatically shown in ~ig. 11, whlch will be descr~bed in detail hsreinafter.

The ~alls of the light channel~ 5a, 5b are advantageously blAckenod, 80 as to be able to better define the liy~t bundle of the light passing from the light source 3 to the test material 1 than if ~here were re~lections on the ~alls of the cavitie8 5a, 5b. In a variRnt, the canbination of light source 3 an~ light channel~ 5~, 5b can be con~tru~ed as a collimator, because a c~llirnatQr is al~o ~n optical element ~efininy the li~ht bundle of the light pas~mg ~om llght ~ource 3 to test material 1. The li~ht sour¢es ~ &an also be cons~LuCte~ as laser diodes ~nd m this case ~ho constructi~n ~f the ll~ht channels 5a, 5b and in particul~r the re~lection characterl6ti~ of the wall~ thereof ~e not as critlcal, because the ll~ht bundle f~m the ll~ht dicde is automat~c~lly well de~ined ~nd the entity $s ~ o~ r!~ y L~ y~lt ~ Or t~e lignc pas~lng ~rom light so~ce 3 to test material 1. In another ~arl~nt the light channels ~an be construc~ed as Winston ~ollectors 2nd further variant~ o~ an optical el~nent deining th~ ht b~ndle of the light p~8~1n~ fl~m the light source 3 to the test m~terial 1 a~e c~cei~able~

,, , ,,, , ,, , _ , ., "_ I i l~

ln ~ f~rth~r v~riane of the cp~ical el~)ent, which def~nes th~ ht bundle o~ tlle light passiny f~n t~e llght solrce 3 to the test m~t~rial 1, ~ iæ
diagr~ml~tically sl~n ln fig. 11, the liyht source ~ Ex)sition~
r~motely fran the cas.tn~ G~ ~ is cc~nected to the llg~t c2~el Sa v~ a liyht guide 36. The pho~iodes 4b are also po~ition~d ~notely of caslng 6b and are colmecte~ to the light ~h~nnel 5b via a light guide 37. Ths s~ns Applie~ ~lth re~s to the photcdio~es 4a in casin~ 6~, but t}~s is nvt shc~n ~n or~er to ~rg~ y figO 11, The light ~uide~ 36 at tl~ end the~of r~snote fn~ ght ~o~lrce 3 ox photodio~e 4a or 4b are ~ rted ~n the corre~ ling li~ht ch nnel o~ q certain length of light guide 36 or 37 ~nd light chennel 5~ o~ 5b. In thl6 sen~e, the li~ht guide6 a~ a~
least partly a~an~d in a~ least part of a light channel.

Fi/3. 11 al80 dlag~a!lmati~ally sl~ th~t the inver~tlve apparatus need only h~ve a s~ngle light sour~e e~r~non to all the te~t ~ els. Irl this va~iant all the light guides 36 ~ c~ptic~lly connect~d to said sinyle light source 3 at the light so~ce-side end th~e~ ~-d ~a~d light source rnust naturally illunin~te all the light guides 3~ d i~ c~ns~quently ~dvantageeusly a light emitting dio~.

It is cl~ar that the photodiode~ 42 o~ . 1 can also be connecte~ w~th their H~ocia~ed lig~t p~ssage6 16 ~ia light ~uides, as i~ ~hown in the l~wer part o~ f~3. 11 with re~p~ct to photodiodes 4b and light ch2nnel~ 5b.
The principle i~ the same and it~ Use can be g~thered ln an obvious manner ~rom flg. 11, SQ th~t th~r~ ~ no need for a more detailed de3cript~0n.

Fig. 1 also ~how~ that in the light ~nnel 5a of the part 10 af the inNentive apparatus 1QC~ted abCVe test materlal 1 can ~e prvvided a fiurthQr ~ptical element ~8, whiCh i~ con~tru~tei a~ ~ plate in the ~ame WAy a~
cptical element 12 and i6 in~erted in oaslng ~a by means of 510t6 3~, 40 m muc~ the s~me way as gla~s pl~te 12 by means o~ 610t3 13, 14. Slot~
3~ and 40 to~ether ~onn a re~e~ for reoeiving t~e plate 38, when thR
cas~ng par~ 8a, 9a are ~o~ned toge~he~ Liyht ~ sa~es 41, 42 a~e provided in the same way a~ ht pa~sageq 15 ~nd 16 ~nd onoe again there is no need for light p~nge 41 if the wall of c~vity 5~ i~ con~tru~ted in such R light-absor~lg mnnner that n~ undesired light ~rom llght emitting ~5 ~J

di~e 3 .~ deflecLed by pl~t~ 38 r~t~lrn~ to th~ laeter and through it to the photodiode 4a.

In one c~stIuction o~ the cptical el~nent 38, the latt.er is ~n th~ foDm of a pvl~rization filter or a ~olo~ filter. A~ m the case of cptlcal el~nent 12, the polar.~zation or colour ~i.lte~ 38 asso~i~ted with the ~ndivid~lal test cl~annel~ tcgeth~r fo~n an .u ~iv.iiual subass~nbly, ~Yhlch i~
r~novably arrang~d in the casing. Such a ~o~arlzation o~ c~lo~r filtex pennits a pol~ri~ation or co~lr d~ff~r~ti~ted detection o~ ~he character-istic~ of the test m~terl~l to ~e tested. The light pn~a~ea 41 ~ld 42 enable the light reflected on the polarl7ation or colour filter 3B to pass cut o~ the light channel 5a and to be opticnally absorb~d, so a~ t~ a~oi~
a di turbance to the testing proeess by 8~id light. As thi~ take~ plA~e in much t~e ~me way as on light pa~sage 15 with ~espect to opt~eal ele~ent 12, it is not ~hawn in order not to overburden the d~win~. Here a~ain, light passage 41 ~n ~e obvi~ted, if the wall of the cavity 5~ ive~
co~respondin~ t-ab~orb~lg con~tLu~tion.

In another con4truc~ion o~ ~he qpt~cal element 38, ~he l~tter i8 con-structed as a secona be~m ~plitter, which i~ once ~ain in the ~orn o~ ~
s~mitran~mitt~ strip mirror fo~mng ~ single su~as6~n~1y and re~va~ly arran~ed in casing 6a~

In a Pir~t variant of thi~ c~stIuction the photodiod~ 4c i8 arranged oncasing ~a and on light pas~ge 42 in much the ~ane way ~s photodiode 4a on caSing 6a a~d on light pas6age 16. The lig~t refle~ted by bean split~er 38 reach~s the photodicdo 4c, in the s~ne way as the light re~lected by th~
beam ~plitter 12 in the c æ e ~ photodiode 4a.

In a 3eeond v~riant of th~ constnuction the photodiode ~c is ar~anged ~n casing 6a, but no~ on ligh't pa~age 4~ ~n mu~h th~ 6ame w~y a~ p~otodiode 4a on c~sing 6a and on llght pa~qe 16. The light reflected by be~
~plltter 38 rea~he~ the p~oto~io~e 40, but it i~ nqw a porticn o~ the light ~m~nating ~rcn light 80urce 3~ B0 that the ~hotcdiode 4c ~.~ u~ed f~r me~suring and option~lly regulating th~ light fru~ light ~our~e 3.

It i~ ~ulvalent to thi~ 6econd variant to le~ve ~he photodiode 4c, as in 5~

the first variant, o;~ ht passage ~2 and t:o so ~ymnet~lcally di~ ce the be~n ~ ter 38 wit:h ~spect to ;nterEace 7a, th~t it de~lect~ psrt of the light f~n light source 3 to ~ t~liale 4c.

~hese different v~ri~t~ of an intrincic~lly unitary construction ar~
mainly suitable for testing a ~;ur~ace of the test material b~ means of inc:ident light or a l~yer or ~ sp~tial portion of the t~st m~terial ~y means oE 'Df3ck- scattereA3 trw~smitted li~ht.

In yet another constmction of th~? cptic~l el~neslts 12 and 38, they are constituted by be~ plitter3, which a~ ~lso cons~ucte~ aq strip mirror el~mentc. T~y are constn~cte~ as par~s of a 6~nitran~n~tting strip mirror onning ~n individual suba~qembly and renovabl~ ~ranged in c~sin~ 6a. In each li~ht channel the str~ he qtrip mi~:ror elenents ar~ i;anitran~-mitting and es6ent~11y oo~rebpond to one another in the s~me w~y qo that, as h~ n fmn ~-~7/03957, to bring about a streaked effect~

In gel~eral it is optlcally s~uivalent to mo~e the ~cnstruction fo~n~ ~y optical elemen~ 12 and a$~tionally 38 fr~m casin1 6a to eas~ng 6b ~nd it i~ also eguivale~t to interchan~e light ~o~r¢~ 3 on cas~ng 6~ ~nd p~oto-diode 4~ on ~asing ~b. For ~his arrange~ent the opti¢ally es~ential element~ ~e di~gramm~tic~lly s~own in fig, 12, ~n additional bebn splittex 38l an~ its as~ociated photoflio~e 4c-be m g provided on c~sing ~a in on~er to permit ~ measurer.en~ ~nd cptlonally a reg~latlon of the light fron liyht source 3.

In the pre~ding description o~ the inventi~e ~pp~ u~ and in the asscci~ted dr~win~, for simpliication purpose~, in each ~ase a con-~tIuct~on with jux~apose1 test chAnnels ~rrang6d ~;n a single row haa been ~ho~en m ex~Tplified manner, The wall~ between the li~ht c~nels 5a or 5b ar~ not ~hcwn ln p~cportion to the other d m ension~ and are inatead ~de m~eh too ~hi~k. H~eve~, ~s the s~reng~h of the app~a~u6, due to the ~sing~ is not dependen~ on sai~ wall~, they ~re in re~làty of th~ ~hinne~s to ensure tl~t they ~e nc:t ~nsparent. Thu~, a pacXing denci~y of ~uxta-posed teRt ch~nels i~ achieved, ~ h pesm~ts an un~ntern~pted te6ting of the test material. Hawever, it i4 better ~na in ~act even neee~
the case of a ~tati~?n~, fl~t ~e~t material ~n o~er to ~chieve an S~
- lB -~nt~r~upted teC;tin;3 thol-evf to )~ve two or more t~s~ ch~nne~ rows in reelproc~lly displac~ uxtc~po~ed m~u)eu with the n~cessAry packing density. In the c~se of a c~st~uetion wi~h two recip~oc~lly ~ir~pl~c~d n~s o~ test charmels this is di~sgr~n~ti.sally shc~ll by means o~ the second cclsiny in ~ig. 1~, whi~h i~ der~vad fr3n fig. 6. El~nent8 5b, 6b, 7b and 8b of flg. 1~ are the ~ne as in fl~. ~. The equivalent of el~nr~nt 9b in fig. 6 is now constructed in two-pcl~t form ~n fi~. 13, BO that a ~econd row of light c~nnels 5b' c~n be ~rranged m the casin~ and n~nely pclrallel to the row o~ light channels 5b, but di~pl~cffd with re~pect thereto, a~ BhOWII
in fig. 13. Apar~ ~r~n the ec~Yequen~es of this di~placement, c~sing part 9b' is equlvalent to c~sing part 9b Ln fig. 6. Be~ween casing pRrt~ 8b and 9~' is Pr~i~d a casina ~Ar~ qh~, wh~P r~rti~n f~ln~ c~ng p~xt 8b, with re~pect to the latte~, .fulils the function of cas m~ part gb in ~i~. 6, ~hllst it~ portion f~oing e~m~ par~ gb', with respect to ~he latter, fulils the ~unction of c~sing part 8~ in fi~. 6, ~o t~t the inter~ace 7b of fig, 6 is ~epl~ced by two .Lnterfaces 7b' and 7~" in fig. 13.

The construc~ion o~ the i~ventive apparabus ra~ains essentifllly the ~ne ~s that de~cr~bed herein~e~o~e in the o~Ye of an ~rrangement of ~v~ral rch~s of te~t c~nnels ~r light chænnal~ 5b and 5b', ~u~h as i6 e.~. ~hcwn in fig. 13, i~e. the ne~e~saxy ~d~ptation~ ~ obvlous t~ the Expert ~nd ~here 1~ no need to go lnto these here. Fbr re~ns of clarity, $t i~
point~d out that ~ption~lly th~re ~xe no li~ht pa~s~ges identic~l to li~ht passages lS ~n~ 41, if n~ ~p~e i8 avail~ble and the~ ~unction ls then fulfilled by a light~bsorbillg ~n~txuction of ~he wall of the li~ht channel~. It is al~o pointe~ vut that the l;~ht ~hannel~ i~ fi~. 13 are shown with the Sbme prqportion~ ~ in ~ig. 6. In fact it wouJd b2 po~s~ble and even ~dvantageo~e to chco~e th~ ~pACing8 between the liyht chAnnels (i.e. th~ wi~th o~ the wall~ ~eparating th~m) ~he ~ame a~ the width ~f ~aid light ch2nnela, s~ that the ale~ o~ the ~est matel~a~ wh~h ~re detected by the light eh~nnels of the ~ir~t and ses ~ row do not overl~p and instead just join one another, BO that the 6nalle~t po~q~ble and th~refore mo~t economic nu~ber of test channel~ is obtained for det~ ng predetenmined ~re~ o:~ the te~t m~terial.

If thexe are two raw~ o~ test o~nnels or l~ght channels, which are identical to one ano~her, i.e. h2ve the s~ne nunber of test ch~nnels and 5~

are subst~l~tiAlly par~llel ~nd clos~ly juxtaposed, thell one rvw can be associated with the light ~u~e-slde pa~t ~ the ot.her row wi~h the converter-slde part o~ tlle inv~ntlYe ~pp~rat~ls, ~o t~t both parts 10 ~nd 29 thereoE a~ locate~ on the same si~e of the te~t material 1. The len~th of the llght souree~side part or the con~erter side part of the light ~hannel can be ~ss~ntially reduced to ~aro and/or the ~all between the light source-side part and the c~lverter ~ide part of the light channel c~n in palt be o~viated, provi~ed that the r~ining par~ of the light channel ~lequately bounds the li~ht pasRing fran the light ;o~Lrce to the te~t n~ter~ al .

dimen~ion3 of the test channels nee~ not be the s~ne. It can ~e ~pprt7priate for variou~ applioation~ to enlarge the liyht ch~nnels a.g, frcm one end of the ru~ to the oth~r, or it can be apprqpriate to con3tmc-t t~e light sour~e-side part of ~he light channel wlth a d ilFfexent cro~s-sectional shape and/or cro~3-sectional ~ace to the conYertel~-side part of the light channel~ The l~ht channels need not nec~ssa~ y h~ve th~
describod qu ~rangular cross-sectivnal sh~ nd the latter can e.g. be circula~, ~hilst the corre~ponding ~vity can be cyl~3rical or e.~.
con~cal, pyrAnidal, etc~

~he rGw~ o~ tes~ channels need not ~e llnc3~ and it can also ba ~pprcpri~te to arrange them along a cuIve~ e.g. an arc for variou~ applic~tions,

Claims (21)

1. Apparatus for the simultaneous non-contacting testing of a surface or internal interface of a test material (1) by means of incident light or a layer or spatial portion of the test material (1) by means of back-scattered or back-reflected transmitted light, in which the apparatus comprises at least one light source (3) and a plurality of test channels, each test channel comprising an optoelectronic converter (4a) and at least one light channel (5a) arranged in the light path between the light source and the converter and in which is positioned a beam splitter element, each light channel (5a) is constructed as an optical element for defining a light bundle, on at least part of the light path located within the same the light channels (5a) are juxtaposed in a common casing (6a) and constructed as recesses passing through the said casing (6a) and the test material (1) is (4a), characterized in that the light channels (5a) have a common plane of symmetry (7a), the casing (6a) is constructed in two parts with parts (8a, 9a) separable from one another in the plane of symmetry, the beam splitter elements are constructed as parts of a beam splitter (12) forming a single subassembly and removably arranged in the casing, and the converters (4a) are arranged on the same casing (6a) as the beam splitters (12) in juxtaposed manner and in each case corresponding to a light channel (5a).

2. Apparatus according to claim 1, characterized in that test material-side ends of the light channels (5a) are congruent with a surface constructed and arranged parallel to a surface (11) of the test material.

3. Apparatus according to claim 1, characterized in that the light source (3) are formed from light emitting diodes or laser diodes corresponding in each case to one light channel (5a).

4. Apparatus according to claim 1, characterized in that the light sources (3) are positioned remotely of casing (6a) and are connected to the light channels (5a) via light guides (36).

5. Apparatus according to claim 1, characterized in that the converters (4a) are formed from photodiodes corresponding to in each case one light channel (5a), which are positioned remotely of casing (6a) and are connected to the light channels (5a) via light guides.

6. Apparatus according to one of the claims 4 and 5, characterized in that each light guide (36) is at least partly arranged in at least part of a light channel (5a).

7. Apparatus according to claim 1, characterized in that the two parts (8a, 9a) of casing (6a) are provided with corresponding recesses (13, 14;
39, 40), which from a recess for receiving the individual subassembly of the beam splitter (12) on joining together the parts (8a, 8b; 9a, 9b).

8. Apparatus according to claim 1, characterized in that polarization and/or colour filter elements (38) are located in the light channels (5a) and are constructed as parts of a polarization and/or colour filter (38) forming a single subassembly and removably arranged in casing (6a).

9. Apparatus according to claim 8, characterized in that the two parts (8a, 9a) of casing (6a) are provided with corresponding recesses (13, 14;
39, 40), which form a recess for receiving the individual subassembly of filter (38) on joining together parts (8a, 8b; 9a, 9b).

10. Apparatus according to claim 1, characterized in that the beam splitter elements (12) are constructed as strip mirror elements.

11. Apparatus according to claim 10, characterized in that in each light channel (5a) is arranged a second strip mirror element (38), whose strips are semitransmitting and essentially correspond to the strips of the beam splitter element (12) constructed as a strip mirror element, the strip mirror elements (38) being constructed as parts of a semitransmitting strip mirror forming a single subassembly and removably arranged in casing (6a).

12. Apparatus according to claim 1, characterized by a second beam splitter element (38) arranged in each light channel (5a), the second beam splitter elements (38) being constructed as parts of a beam splitter (38) forming a single subassembly and removably arranged in casing and by in each case a second converter (4c), which is positioned facing the second beam splitter element (38), in the same way as the first converter (4a) faces the first beam splitter element (12).

13. Use of the apparatus according to claim 1 for testing a supposedly smooth or regularly structured surface or internal interface of the test material for irregularities thereof.

14. Use of the apparatus according to claim 1 for testing a light trans-mitting, supposedly homogeneous or regularly structured layer or a light transmitting, supposedly homogeneous or regularly structured, spatial portion of the test material for irregularities therein, such as inhomo-geneities and inclusions.

15. Use of the apparatus according to claim 1 for testing a supposedly stationary surface or internal interface of the test material for position changes to said surface, which are e.g. caused by movement, vibration, expansion, shrinkage, growth, deposits and the like.

16. Use of the apparatus according to claim 1 for testing the concentricity of a shaft for concentricity errors, particularly vibrations, optionally as a function of the rotational speed of the shaft.

17. Use of the apparatus according to claim 1 for testing a light transmitting, supposedly stationary layer or a light transmitting, supposedly stationary spatial portion of the test material for movements and in particular vibrations of inhomogeneities or inclusions in the the material, as well as particles suspended or floating therein.

18. Use according to either of the claims 13 and 14, characterized in that on one side of the test material is located an apparatus for testing the test material by means of incident light or back-scattered transmitted light and on the other side thereof is provided a retroreflector for the transmitted light.

19. Use according to either of the claims 13, and 14, characterized in that on one side of the test material is provided an apparatus for testing the test material by means of incident light or back-scattered transmitted light and on the other side of the test material is positioned an absorber for the transmitted light.

20. Use according to one of the claims 15 to 17, characterized in that on one side of the test material is provided an apparatus for testing the test material by means of incident light or back-scattered transmitted light and on the other side of the test material is provided a retroreflector for the transmitted light.

21. Use according to one of the claims 15 to 17, characterized in that on one side of the test material is provided an apparatus for testing the test material by means of incident light or back-scattered transmitted light and on the other side of the test material is provided an absorber for the transmitted light.