DE2023739A1 - - Google Patents

Description

PATENT ADVOCATE!

DR. M0LLER-BOR6 DR. MANlTZ. DR. DlUf ⁵ IL DlPL-ING. RNSTERWALD D1PL.-ING. GRÄMKOW - SMONCHEN 22, ROBERT-KOCH-STR. 1 - TELEPHONE 225 110 -

Ή. May 1970 Hl / th - C 2184

COMPAGHIE GENERALS D'ELECTEICTTE 54-, Hue la Beetie,
75 Paris 8 / France

Device for collecting light in a cylinder

The invention relates to the collection of light along a rectilinear section «It concerns, among other things, the drilling of cylindrical holes by means of a laser in translucent, particularly hard materials such as diamond or corundum.

It is known that the collection or concentration of light takes place by means of lenses or curved mirrors and goes by Light source. with high energy concentration on an extremely limited surface aue. Eb so become tools that allow the precision machining of certain parts of dielectric material by an electrical Breakdown can be generated} A triggered laser is used as a light source. The breakthrough sets a when a certain threshold of the electric field dea light © »is achieved and runs in a very" restricted Time; away·

003848/1253

A known device _? which ensures the collection of light bundles is aas Cassegrain * = !? ernrohr ξ a large concave mirror reflects the light beams onto a convex mirror, dsr the rays through a central opening of the large _mirror's reflected behind the? an eyepiece lens is arranged »This device allows the reduction of the aberration»

In the Sanai & lung "dzi / o Consumption of the Lieht

The known devices © »form a conical Energy package => whose power density is very high in the area of the focal point, the vertex of the cone

Weaa © s is desired to be a. The electrical Dareteehlag does not measure "a hole to be drilled with a relatively large 5? Depth"

also, in a certain i'ostand "toh diasesi". can be obtained. Bas hole obtained has dans © ine allgemin conical © form on which "it is · often desirable is wide _& Hun" example "in the Fäh © & Θ & focus narrow and ia distance iron this b @ £ machining nozzle, one in essential sylinäriachas hole au preserved ». . . ;

The aim of the Krfindumg is the elimination of the above-mentioned section wA di © Schaffujog © ia © s Iasisg © ®og © a.e3a Zons of the Riergiekonseatratioas, d © r @ a for® practically syliadriscb. and in which the löergieclicht © practically uniform along the Syiinderactisö is "The Bolaren ^ l'rlsen and Sctuieiden a material came with increased Präaision be executed = 35s ie-t siöglich _s a 3Düs ©

BATH

to be carried out in a very hard material such as diamond ' or corundum. The breakdown in the dielectric material is triggered by a laser in a a very short time along a practically cylindrical Receive channel

To this end, the invention provides a device for collecting von Lieht in the volume surrounding a straight line segment that uses a light source illuminating an optical system because β is coaxial with the portion and focuses the light in the vicinity of the section and * is characterized in that the optical system an exit pupil or exit aperture comprising the Has the shape of a bing enclosed between an inner and an outer coaxial circle, wherein the focal point of the systems beyond the straight line committee The diameter of the inner circle is chosen to limit the area of the Tangential caustic and on the side of the focal point a limitation of the area of the sagittal focal point is generated · The diameter of the outer circle is chosen so that a delimitation of the area of the sagittal focal point is produced on the side of the optical system is · The two diameters are chosen so that the two areas mentioned above are mutually exclusive.

The optical system can have a concave mirror provided with a central hole through which the from The rays emitted by the source go to one Convex mirror, which reflects the emitters on the concave mirror, which the reflected rays to hit sent back the straight section

■ - 3 -

009848/1253

Invention becomes old in the following described for example} in this E © igt4

Pig »1 schematize the geometrical Lichtstrafclen · - run in a light receiver device two mirrors »one convex and one concave mirror,

Pig * 2 and 3 a detail of the attachment of the umbrellas on a tear saver (embossing,

Pig · 4 · the detail of another way of fastening the ' Bchinae by means of rods in steraform and

Pig «. 5 ^ an enlargement of the energy conaeation «= Zone.

In the Aaeftthaingsfosm sung in Pig "1 there is a light falling in", the wavelength of which is 0.1 u and 200 u lie kana ,, d. 1bu which is ultraviolet, siclitibar or infrared, absorbed by a source with parallel bundles like a reader «, the bundle assumed to be parallel passes through a kffeie opening 1, which is provided in a spherical concave mirror 2 with © ines Kruramussg® ·· center Og Eb then meets a spherical convex mirror 3 with a point Q ₁ ^ and, for example, a parallel assumeddinfallomle tiert as if it were from dea Bre
would kofflmen «Eb is a so-called
mirror 2 reflected

The place of the center of curvature can be set so that th, at 4 · on the axis © des

is tric, grooved to the focal point®a

BATH ORIGINAL

9Q48 / 1253

For example, rays at a maximum distance. of the concave mirror 2 takes place approximately twice the distance ρ of the focal point J '^ from the concave mirror 2 corresponds to

In such a case, the angle & formed by the reflected beam with the system axis at F ^ is essentially equal to four times the angle of incidence i * The angle β formed by the normal of the concave mirror 2 with the system axis at Qg is then essentially equal to three times the angle of incidence i . Also in the _Λ same case, the angle of incidence formed by the focussed, reflected rays with the system axis at 4 is. Cutting angle X essentially equal to twice the angle of incidence i. It is therefore (λ ar 41, ß * 31, tfSf Se is a matter of simplifications that facilitate the explanations. The exact relation connecting the angles is <* «β + i» Γ + 2i, where «and ß in the general case are compiled functions of i.

Since an opening f / 1.4 is required for the convex mirror 5, the maximum angle is t *. substantially equal to 18 °. From this, a maximum angle of incidence i of essentially equal to 4.5 ° can be derived. The rays reflected at this angle are focused on the axis of the syete on a point that is closer to the vertex of the mirror than the points of the other rays corresponding to smaller openings. An outer screen 5 fades out the outer rays and thus limits the collection of rays on the mirror-side system axis. This outer position corresponds to an angle of intersection of essentially 9 °. The paraxial image of the

009848/1253

focused light is the farther yqb away from the mirror, Je kleiaei? the angles of incidence are "An inner screen 6 blinds the rays auej - the 'smallest opening eateprechea" ad in the Iah © of the focal point are focused "This © outermost position corresponds to an angle of intersection ei toja i® essentially equal to 6 ° and a« © Angle of incidence i on the loaksir mirror 2. of essentially equal to 3 ° B®3? reflective part of the concave mirror 2 corresponds to a sphere sone. which is enclosed between two angles, that is essentially Avian J χ 5 ° · 9 ° uM 3 χ 4.5 ° ^s 13 _? 5 ° lie-geao Ber reflexiereade feil dos SosFessp
Ball teeth _for the Bwis © h @ a sw @ i Wi ^ k «
s € ai eats that lie in the w © e © atal © a / 2 κ 5 ^{s »}

Sa the in de »Flg« 2 g 5
Bind der outer Schina 5 ¹ S ^ dd © r lsae ^ e screen 6 at height © dee convex mirror 3 angeordseto bubble screen © are on a (JlassMck 7 or the like a g © tragea. _S -that has a © low view © _s for the The flour used is permeable and only provokes a weak bundle of lightness
form. In Fig. 4 is «ine suader ·
Rods 8 low bend geseigti the io Foi »armed stem» arranged leg 'köiaiia <i Xh dieBea fall int the Olastrttger no longer required · »

Meanwhile, the position of the two screens is k "indsnr®g @ ~ 'yon Meaning. You can click on one or / and the other of the

009848/1263

Mirror or at each between the light source and the Be located in the area of the energy collection. (In fact, the maximum and minimum cutting angles white, for example with 9 ° and 6 °, the ends of the Geraaenabeehnitieß the energy collection and allow, the dimension of the opening of the outer screen 5 or the Dimensions of the inner screen 6 to be obtained.

The umbrellas can be detachable and interchangeable with others Umbrellas that are made with calculated dimensions to different cutting angles and lengths of the straight section to get the energy collection.

Venn, however, the cutting angle and the length one for everyone Once set, it is possible to limit the pupils by machining the optical surfaces of the Execute concave mirror 2 and the convex mirror 3. The optical surfaces are then based on the dimensions of the outer and the inner screen are defined »the would be positioned at the location of the mirrors. In this case the screens are no longer required.

5 shows an enlargement of the (^ collection zone obtained along a straight line section 4 according to the example set out above.

A sagittal collection is obtained along a straight line ~ * Section 4, with the (tangential caustic 9 at the height the sagittal plane is suppressed due to the presence of the inner screen 6.

Thus, if, for example, ρ «240 mm and p ¹ ·« 2p * 460 mm, the radius of curvature R _{2 of} the concave mirror would be 2

009848/1253

be approximately 360 mm. The angles of incidence i iron 3 ° and 4.5 ° correspond to a pupil or «. BXend of concave mirror 2 with a radius of imgefäin? 5 ^ »and 8 cm» In this case, the slope of the 3 and 4 arranged screen® wipe the basement iros approximately 28 ram and 44 rain bordered. One obtains in relation to inen Point P, which corresponds to a very small angle of incidence i and for which p * «480 mm, is a straight section AB, its Abftzisso 'approximately between 1.3 »Ε and 3 * 3 sam in is on point F

According to FIG. 5, the point of contact 10 is the tangential caustic ^ "with the reflected ray, its angle of intersection 6 °, di® tangential caustic feet, since the inner ßcfeirm 6 the rays with smaller, ßchnittwinkel holding back. The same screen intersects the sagittal area at B about 1.3 saa before F from »The outer® screen 5 limits the sagittal area at A »

At large angles of incidence, the same change is in favor of this angle the focused reflected rays iramer more distant from each other; however, they v / ground the Luminous flux reflecting optical surfaces are also larger. These two effects compensate for the calibration and the energy contamination takes place with a practically constant density over the entire length of the Oevodenebechalttäe, d · Iu in a practically cylindrical Voltwsea ^ that. Lungs little " stone ten times larger than the diameter iet «

In the device according to the invention, certain Arrangements changed or certain arrangements made equivalent facilities are to be erected,

π α? ι * .; 8/12 ο 3

The light source can be a quaci point source like be an arc.

Instead of the two mirrors described above, the concave and the convex mirror can also have two lenses, a diverging and a converging lens, their exit pupils have a ring shape, also produce a practically constant energy concentration along a straight line section.

In the Fay. a point source allows a simple one as well Concave mirror with a large opening, which has an outer pupil in the shape of a ring, to obtain the same result.

The invention is applicable to drilling by means of a laser of transparent and hard materials like diamond »It is particularly important in areas where the Regularity of a hole with respect to the depth must be guaranteed. This regularity is with the invention Device that realizes a concentration of energy with constant density ensures

-Fatentan claims-

- 9.-009848/1263 SAO

Claims (3)

Claims Device for collecting light with a substantially constant density in a substantially cylindrical Volume »especially for drilling holes with laser beams in a transparent material ^ with a optical focusing system whose optical axis with coincides with the axis of the volume and its focal point lies beyond the point furthest from the volume, characterized in that that it comprises a bing diaphragm or singhole disk arranged coaxially with the optical system, which between the System and the position of the room is arranged »in which calibrate the volume, where the .internal diameter the diaphragm is dimensioned in such a way that the tangential focal point of the device formed in this way is at the same height of a point is limited »the ¥ or the volume on closest point is located, and the outside diameter the diaphragm is dimensioned in such a way that the sagittal focus of the device thus formed is bounded by the point which is located in front of the point closest to the volume 2. Device according to claim 1, characterized in that g e k e η η eeichnet, that the optical system has a concave mirror provided with a central hole, its reflective surface facing the reflective surface of an equiaxed convex mirror is. 3. Apparatus according to claim 1, characterized in that the annular aperture on one transparent carrier is attached «, - 10 ~
009848/1253 Device according to claim 1, characterized in that the annular aperture diaphragm is made up of an opaque circular disk and an opaque plate perforated by a circular hole
is formed, the circumference of the disc and the opening defining the edges of the annular disc and the plate and the disc connected by means of rigid radial rods feet "ind. ORIGINAL 0Ο98Α8 / Ί2Β3