LU80320A1 - METHOD AND DEVICE FOR PRODUCING AN INTERMITTENT LIGHT BEAM - Google Patents

Description

AT ALL ~ ^ GRAND-DUCHY OF LUXEMBOURG BL-2478 / EM / vd of the Minister _ .. ...., 1¾¾¾¾ of the National Economy and the Middle Classes

Industrial Property Service

Ij ^ eman <^ e ^ dream ^ of invention I. Request

The METALLURGICAL RESEARCH CENTER, CENTRUM VOOR RESEARCH IN DE METALLURGE non-profit association, vereniqlng zonder winstoogmerk .__________________________________________ (u 47 ..... rue..MontOYer, ...... B „-..... 1040 Brussels, Belgium............................................... ..............................

re ^ réiB.ein.tê-p.ar .... M "Ern & s.fc .... J! ŒYERS.". ^ ngL ".cQn.s ^^ aM ^ PJ ^^^ ____________________________ (2) ' 21 bd ...... Joseph II, LUXEMBOURG, acting as authorized representative ooaêP ° se ........ this three October one thousand nine hundred seventy-eight at ........ 1.5 ................ hours, at the Ministry of National Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent for invention : "..... Method and device for producing a light beam .................. (4) ........ intermittent" .... .................................................. .................................................. .................................................. ..................................................

declares, assuming responsibility for this declaration, that the inventor (s) is (are): MQnsis.ur ..... J.e.a.n ..... CBÂmif.,. 314 .... J.fc.er, B ....- 4..8ia ... ZBMO.QRCHMP.S „.................... ............... © 2. the delegation of power, dated _____......................... ................. on .... 2.9 ..._ segtCTi) re;., ... 197i 3. description in language ........ .... Î. £ & DÇai.se ............................... of the invention in two copies; 4 ............ 3 .................. drawing boards, in two copies; 5. the receipt of the fees paid to the Luxembourg Registration Office, on October 3, one thousand nine hundred and seventy-eight ....................... ......................................

claims for the above patent application the priority of one (s) application (s) of (6) _______________________________ / ......................... ................................... filed in (7) ------- ---------------------------------------------------------- ---------------------------------------------------------- -------------------- the ............................. .......... i --------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- --------------- (8) on behalf of ____________ L ............................ .................................................. .................................................. .................................................. ............................................ (¾ chooses domicile for him (it) and, if appointed, for its representative, in Luxembourg ------------------------------------ - ..... Joseph ..... II ..................................... ..... .................................................. .................................................. .................................................. ..ao) requests the issuance of a patent for the subject described and represented in the abovementioned appendices, - with postponement of this grant to ..... diX. “hUit ........ month.

The agent..................................

......................- ·· W * ~~ / 1 Π. Deposit Minutes

The aforementioned patent application has been filed with the Ministry of National Economy. and the Middle Classes, Industrial Property Service in Luxembourg, dated: October 3, 1978 OO. ·· "Pr · the Minister to ............ 15 ....... .. hours / // ^^ v) ° ^ ï ^ onomie Nationale / QkdjKTClasses averages,

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A 68007_ \ ', v ...... X' / _ / 7 / _ t * BL-2478: C 1905/7810.

PATENT

= c = 3Sncs = c = a = sass: as: =: sBsaB3assâE: = B3 & sax j METALLURGICAL RESEARCH CENTER - 'CENTRUM VOOR RESEARCH IN DE METALLURGIE,,' Non-profit association - | Vereniging zonder winstoogmerk in BRUXELLES, (Belgium) '.

| Method and device for producing an intermittent light beam.

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The present invention relates to a method! ; and a device for producing at least one light beam. intermittent by transformation of a continuous light beam.

It is known to carry out such a transformation by placing, periodically, on the path of the continuous light beam, an opaque screen possibly carrying a slot or an appropriate orifice. In this way, the intermittent light beam is obtained, either by periodic interruption by means of the opaque screen or by periodic passage through the slit jdL.

2.- *, or the opening of the said screen. A type of device generally used for this purpose consists of a rotating disc carrying notches at regular intervals over the entire length of its periphery. By rotating this disc at an appropriate speed, the desired frequency of the intermittent beam can be ensured.

The applicant has sought to apply this technique with a light beam, such as for example a suf- laser | powerful enough to engrave a chosen design on the surface | of a rolling mill cylinder by local destruction of the material! constituting said surface. He was thus confronted with the i \ | - following difficulties. The interruption of the continuous beam, which generally occurs during half of the total time of use, constitutes a significant loss of power in the l | case of the application envisaged by the applicant. In addition, such an interruption is accompanied by phenomena such as heating of the interceptor screen and reflection of stray beams .m which pose problems which are always costly to solve.

3 The present invention relates to a method making it possible to remedy the difficulties set out above.

The method, object of the present invention, in which a continuous light beam is interrupted by periodically moving an opaque screen transversely to the path of said continuous beam, is essentially characterized in that the said screen is provided, on at least one from its two faces and at preferably regular intervals, reflecting zones of possibly different and in this case alternately different specific characteristics, in that by means of the reflecting zone receiving the impact of the beam, the latter is deflected towards an auxiliary optical circuit with which the deflected beam is given, directly or indirectly, a predetermined final position and direction and in that the number of reflecting zones of different characteristics is fixed according to the number j of intermittent beams to be formed .

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According to a first embodiment of the invention, the two faces of the interceptor screen are provided with reflecting zones and by means of the auxiliary optical circuit, the position deflected by the reflecting zone receiving the impact of the continuous beam is given and a predetermined final direction by returning this beam to a reflecting area on the opposite face.

According to a second form of the invention, the. ’Reflective zones are separated at intervals, preferably regular, by a notch which allows the continuous light beam to pass through, without deviation.

According to another embodiment of the invention, the reflective zones have identical characteristics and are separated by) #; rees from each other by a notch allowing the continuous light beam to pass, which allows two intermittent beams to be obtained.

According to the invention, the translation and / or rotation of at least one element of the auxiliary optical circuit advantageously makes it possible to adjust the position and / or the direction of the intermittent light beams relative to the beam; continuous light.

Also according to the invention, the duration of each intermittent beam depends on the size of the reflecting zone and on the speed of movement of the screen.

In the case where the intermittent beam or beams are projected onto a moving surface, the movement of the interceptor screen and that of this surface are advantageously synchronized so as to have the relative rest between said surface j and the beam interceptions.

i! j According to a particularly advantageous method I of the invention, the movement of the interceptor screen is a ‘rotation about an axis, preferably parallel to the direction; of the continuous light beam.

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In the latter case of a rotational movement, the screen is advantageously given the shape of a disc, the reflective zones and any notches are concentrated at the periphery of this disc which is placed so that during its rotation, only the peripheral strip of the disc intercepts the continuous light beam.

According to the invention, the continuous light beam can be a coherent light beam, such as for example a laser, with a power possibly greater than 100 watts.

The transition from one position to the other of the intermittent beam takes place gradually as the discontinuity between reflecting surfaces or between reflecting surfaces and notches enters the continuous beam.

After a complete revolution of the circular screen, the situation becomes identical to what it was at the start, the frequency of passage from one position to another of the intermittent beam being equal to the product of the number of surfaces reflected -] health of similar characteristics lining the periphery of the disc by the speed of rotation expressed in revolutions per second.

The present invention also relates to a device for implementing the method described above.

The device, object of the present invention, is essentially characterized in that it comprises: a) a continuous light source, the emission of which is preferably | concentrated by appropriate means in a particular direction, b) a rigid screen, of circular shape, able to rotate around; an axis preferably parallel to the direction of the continuous light beam, so that only the peripheral strip of this screen intercepts this light beam, said peripheral strip carrying on at least one of its two faces, 1 of the zones reflecting the beam intercepted and possible-

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9 i 5.- 1 st between notches alternating with these reflecting zones, these notches allowing the continuous light beam to pass without deflecting it, c) an auxiliary optical circuit associated with the intercepting screen comprising at least one reflecting element for receiving the deflected beam and give it, directly or not, a predetermined final position and direction, the said reflecting element being able to be displaced in a translation, for example parallel to the direction of the continuous beam and / or a rotation around an axis, for example vertical and perpendicular to the direction of the continuous beam.

According to a variant of the invention, the interceptor screen carries reflecting zones on its two faces and 1 auxiliary optical circuit comprises at least one pair of reflecting elements for receiving the beam deflected by the reflecting zone receiving the impact of the beam continuous and return it to a reflecting zone on the opposite face of the interceptor screen, this last reflecting zone being intended to give the beam thus deflected a predetermined final position and direction.

According to one embodiment of the invention, the auxiliary optical circuit associated with the interceptor screen is advantageously composed of mirrors.

According to another embodiment of the invention, the reflecting zones are advantageously made of polished metal (for example aluminum) or covered with a layer of polished material (for example a layer of polished gold).

It is obviously not beyond the scope of the present invention to combine several devices of this type, for example several screens and auxiliary optical circuits in series, to increase the number of intermittent beams and / or equalize their intensity (in the case where successive reflections alter the intensity of the beams).

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Figures 1 to 4 appended are given by way of nonlimiting example, to make the object of the invention clear.

Figure 1 is a block diagram showing the transformation of a continuous light ray into intermittent light rays, by means of a circular screen and an optical circuit | as auxiliary, in accordance with the invention.

Figure 2 is a block diagram of a variant; .Figure 1: the circular screen carries reflective zones on one side and the auxiliary optical circuit comprises a single mirror ·.

Figure 3 relates to the translation of the auxiliary optical cir-cuit parallel to the direction of the continuous light beam, in order to change the position of the intermittent beams by a desired distance.

FIG. 4 relates to the rotation of a mirror of the auxiliary optical circuit around a vertical axis perpendicular to the direction of the continuous light beam, with the aim of modifying the direction of the intermittent beam.

According to FIG. 1 a, the interceptor screen is a disk 1 which can rotate around an axis 2 parallel to the direction of the continuous light beam 3.

View 1b of the interceptor screen 1 shows that the. . periphery of the disc, is provided, on its two faces, with N zones

; , bending '4 of' identical characteristics, separated by N

• indentations 5. The reflecting zones of one face of the disc 1 make an angle of 90 ° with the reflective zones of the opposite face of this disc.

Figure la. also represents the auxiliary optical circuit 6 associated with the interceptor screen 1. This circuit is composed of two oblique mirrors 7 and 8 at right angles to one another.

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Two situations arise when the continuous light beam 3 is emitted towards the screen 1.

When the beam 3 reaches the screen 1 at the moment when a notch 5 is on its trajectory, this beam is not deflected and continues its path beyond the screen 1 according to 9-

When the beam 3 reaches the screen 1 at the moment when a reflective zone 4 is on its trajectory, this beam is | deflected towards the mirror 7 which reflects it on the mirror 8! which to its all refers to the reflective zone 4 'located on! the opposite face of the screen 1. This zone 4 'then reflects the! deflected beam, in such a way that its final position and direction 10 are different from those of the extension of the continuous light beam 3. This possibility of modifying the position! and the direction of the beam is due to an adequate use of the auxiliary optical circuit 6 which will be detailed in the comments relating to FIGS. 3 and 4.

If the periphery of screen 1 has 100 zones; reflective 4, of similar characteristics separated by 100 notches 5 and if the screen 1 rotates at a speed of 100 revolutions per second, the frequency of passage of a beam not! deflected to a deflected beam is 10,000 Hz.

According to FIG. 2, the interceptor screen is a disc 11 which can rotate around an axis 12 parallel to the direction of the continuous light beam 13. Unlike the dis- | as 1 in FIG. 1, the periphery of the disc 11 is provided on: a single face with N reflecting zones 14 with characteristics j! i identical separated by N notches 15. The auxiliary optical circuit 16 associated with the disc 11 is composed of a mirror 17.

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The beam 12 continues its path at 18 without deflection when it encounters a notch 15 in the disc 11 and is deflected at 19 when it encounters a reflecting zone 14 and the mirror 17.

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According to FIG. 3, the auxiliary system 6 composed of the two perpendicular mirrors 7 and 8 is offset by a distance d relative to the circular screen 1 provided, on its two faces, with reflective zones 4 and 4 ′ and notches 5.

When the continuous light beam 3 reaches the screen 1 at the moment when a notch 5 is on its trajectory, this beam is not deflected and continues its following path 9 beyond the screen 1.

When the continuous light beam 3 reaches the screen when a reflective zone 4 is in its path, it is deflected towards the mirrors 7 and 8 and then onto the reflective zone 4 ′ which directs it in a final direction parallel to the direction 9 of the beam not deflected, but distant from the latter by a distance e. The offset d of the auxiliary optical circuit 6 caused the parallel displacement of the deflected beam by a distance e such that e = 2 d. This offset d can be made in both directions relative to the plane of the screen 1 which represents the neutral position of the circuit 6 and the displacement e can therefore take place in both directions relative to the j direction 9 of the non-deflected beam . The offset d of the optical circuit 6 can be adjusted very finely, for example by means of a micrometric screw.

i According to FIG. 4, the mirror 8 forming part of l. auxiliary optical circuit 6 is offset by an angle · # with respect to its normal position with respect to the mirror 7 (right angle).

The screen 1 is provided, on its two faces, with reflective zones 4 and 4 ′ and notches 5.

When the continuous light beam 3 reaches 1 ′, screen 1 at the moment when a notch 5 is on its trajectory, this beam is not deflected and continues on its next path 9, beyond screen 1.

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When the continuous light beam 3 reaches the screen. j 1 when a reflective zone 4 is on its trajectory,! it is deflected towards the mirrors 7 and 8 and then towards the reflective zone 4 ′ which directs it in a final direction 21 that is forgotten only with respect to the direction 9 of the non-deflected beam. The rotation of the mirror 8 by an angle cr with respect to its normal position: (perpendicular to the mirror 7) therefore had the effect of displacing the deflected beam 21 by an angle a = 2 a with respect to the non-deflected beam 9. The relationship between a and oc * obviously depends on the shape of the auxiliary optical circuit 6. The offsets! a and a 'are obviously feasible in both directions and can be adjusted very finely by an appropriate means.

! The method and the device for its implementation described above therefore have the following advantages: 1) when the intermittent beams are projected onto a moving surface, the speeds of said surface and of the interceptor screen can be adjusted for have the relative rest between this surface and the beam interceptions.

2) elimination of the loss of power and of the problems of heating and reflection of parasitic beams due to the use of a screen carrying only notches generally practiced until now, 3) possibility of shifting the beams intermittent either in parallel translation or in rotation of a very small quantity compared to the non-deflected beam.

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Claims (11)

10.-; claims î ______________________________ 1. Method for producing at least one beam; intermittent, in which a continuous light beam is interrupted by periodically moving an opaque screen transversely | to the trajectory of said continuous beam, characterized in that one | provides the said screen on at least one of its two faces, and inter-; preferably regular valleys, reflective areas of character; possibly different and in this case, alternatively different specific characteristics, in that by means of the reflecting zone receiving the impact of the beam, the latter is deflected towards an auxiliary optical circuit with which one gives, directly or not, to the deflected beam a predetermined final position and direction and in that the number of reflecting zones of different characteristics is fixed according to the number of intermittent beams to be formed. 2. Method according to claim 1, character- | laughed at by having both sides of the interceptor screen! reflective zones and by means of the auxiliary optical circuit, the beam deflected by the reflective zone receiving the impact of the continuous beam is given a predetermined position and direction by returning this beam to a reflected zone! from the opposite side. 3. Method according to either of Claims 1 and 2, characterized in that the reflecting zones; are separated at preferably regular intervals by a swap! tarure which allows the continuous light beam to pass without deflection. 1 è ~> t ”! J 11.- V 9 *% I '4. Method according to claim 3, characterized 0 1. in that the reflecting zones have identical characteristics and are separated from each other by a notch allowing the beam to pass continuous light. 5. Method according to either of claims 1 to 4, characterized in that the translation and / or the rota- | tion of at least one element of the auxiliary optical circuit allows; ; adjust the position and / or direction of the light beams! : intermittent with respect to the continuous light beam. 6. Method according to either of claims 1 to 5, characterized in that the duration of each intermittent beam depends on the size of the reflecting zone and on the speed of movement of the screen. 7. Method according to one or other of the claims; tions 1 to 6, characterized in that, in the case where the intermittent beam or beams are projected onto a moving surface, the movement of the interceptor screen and that of this surface are synchronized to have the relative rest between said surface and beam interceptions_ 8. Method according to either of claims 1 to 7, characterized in that the displacement of the interceptor screen is a rotation about an axis preferably parallel to the direction of the continuous light beam. 9. Method according to claim 8, characterized in that the screen is given the shape of a disc, in that one concentrates the reflective zones and possible indentations at the periphery of this disc as the it is placed so that during its rotation, the only peripheral strip of the disc | intercepts the continuous light beam. - • "“ 'N _ "fi /' fl '12 · - {10. Process according to either of Claims 1 to 9, characterized in that the continuous light beam j ^ ·! is a beam of coherent light, such as for example a laser, Η Ί with a power possibly greater than 100 watts. !! 11. Device for implementing the process described in either of claims 1 to 10, characterized in that it comprises: a) a continuous light source whose emission is preferably concentrated by appropriate means in a particular direction, b) a rigid screen, of circular shape, capable of rotating around an axis, preferably parallel to the direction of the continuous light beam, so that only the peripheral band of this screen intercepts this light beam, said peripheral strip carrying on at least one of its two faces reflective zones - the intercepted beam and possibly notches alternating with these reflective zones, these notches allowing the continuous light beam to pass without deflecting it, c ) an auxiliary optical circuit associated with the interceptor screen comprising at least one reflecting element for receiving the deflected beam and giving it, directly or not, a position and a direct predetermined final ions, said reflective elements being able to be displaced in a translation by! ^ * jj example parallel to the direction of the continuous beam and / or one, * rotation around an axis for example vertical and perpendicular '5 j to the direction of the continuous beam. i; j · ^. 12. Device according to claim ll, charac-! : terized in that the interceptor screen carries healthy reflected zones on its two faces and the auxiliary optical circuit includes two reflective elements for receiving the beam deflected by the reflective zone receiving the impact of the continuous beam and returning it to a reflective zone from the opposite side t · * * Æ 13.-! y i, u of the interceptor screen, this last reflecting area being I, intended to give the beam thus deflected a predetermined final position and direction. 13. Device according to either of the following | claims 11 and 12, characterized in that the auxiliary optical circuit associated with the interceptor screen is composed of mirrors. I. ' ). 14. Device according to one or other of the re- | sales 11 to 13, characterized in that the reflective zones | 'your are polished metal (eg aluminum) or covered with a layer of polished material (eg a layer of polished gold). j: | . \ \! i i! t ’f I. j