A PROCESS FOR THE COLD REALIZATION AND HOT COINAGE OF PRISMS ONTO METHACRYLATE OPTIC CONDUCTORS, AND DERIVED PRODUCT

Abstract: A process for cold- and hot-working of methacrylate optic conductors (M), of cylindric or of any other shape, that allows a beam of light, inserted into said conductors, to be totally inwardly reflected according to the angles contained in the limit angle of the total internal reflection, and determines the emission according to beam angles until - in theory - 180 DEG amplitude but, in the practical industrial realizations, of 30 DEG or 56 DEG , from the section of the conductor opposed to the one carrying the reflection means (2).

Description: "A PROCESS FOR THE COLD REALIZATION AND HOT COINAGE OF PRISMS ONTO METHACRYLATE OPTIC CONDUCTORS, AND DERIVED PRODUCT" The present invention concerns a cold realization and hot coinage process of prisms onto methacrylate optic conductors, and derived products. It is well known that methacrylate optic conductors conduct the light radiation according to the principle of the limit angle and of the total reflection. It is the aim of the present invention to realize a working process for said optic conductors, of cylindric or of any other shape, that allows a beam of light, inserted into said conductors, to be totally inwardly reflected according to the angles contained in the limit angle of the total internal reflection, and such as to determine the emission according to beam angles until - in theory - 1 80° amplitude but, in the practical industrial realizations, of 30° or 56°, from the section of the conductor opposed to the one carrying the reflection means. The aim set forth is reached, according to the present invention, by a cold-working, comprising one or more constant pitch millers for the realization of a plurality of parallel specular prisms with a perfectly plane and bright surface, engraved onto the surface of the optic methacrylate conductor; or by hot-working, with a tool consisting of a copper parallelepiped, inside crossed by resistances and thermostats which allow a controlled heating, and of an engraving area that coins the micro-prisms onto the bar. The advantages deriving from the present invention are many and considerable: - with the hot- or cold engraving of prisms onto conductors with round square section, beam emissions may be obtained according to adjustments of 30° and 56° from the section of the conductor opposed to the one being worked; - with the same engraving of the prisms onto plates or conductors with prism shapen said workings allow emissions orthogonal to th light source; The present invention will be explained more in detail hereinbelow relating to the enclosed drawings in which some embodiments are shown. Figures 1 and 2 show an axonometric view of a device for the hot-realization of two variants of the process according to the present invention. Figures 3 and 4 show the miller for the cold-realization of prisms with emission angles of 30° and 56°, onto methacrylate bars M. Figures 5, 6, 7 and 8 show some variants of methacrylate bars worked according to the present invention, with prisms characterized in emission angles of 30° and 56° and with great arrows showing the light inlets. The enclosed figures show a cold- and hot-realization process of prisms coined onto methacrylate optic conductors and derived products, performed onto a vertical working centre with a useful run of 1 .300 mm and with a reference system that may move the methacrylate bar M without errors of re-placing, allowing to work also onto bars longer than the machine's run, and onto which an angular head of 90° is mounted which allows a cold- working with a disc miller 1 and then with a circular saw with a diameter of 125 mm, modified at 100°, and to polish with a cbn (borazon) grinding-wheel for allowing a wall of parallel optic prisms 2, realized onto a bar M, as specular as possible. In a possible variant, the coupling of n constant pitch millers may be introduced for increasing the industrial production times, with the following milling parameters: revolutions s = 470 rev/min advancing f = 370 mm/min These parameters have been determined by way of experiment so as to avoid micro-vibrations of the miller that might make the surface of the micro-prisms not perfectly plane and bright: without this condition, the efficiency of the device experiences a drastic falling off. Besides the already described details, figures 3 and 4 furthermore show the rotation sense C of miller 1 and its excursions D, E and A - respectively longitudinal, vertical and angular - of said miller. For what concerns the process for the realization of the methacrylate optic conductor by means of hot-working, the methacrylte bar M is placed onto a tool-carrying structure D, fixed to the base B by means of supports 4 for allowing the contact with said bar and the vertical sliding of the tool, consisting of a copper parallelepiped crossed inside by resistances and thermostats which allow the controlled heating thereof, and of an engraving area that engraves the micro-prisms 2 onto the bar. The vertical descent of the tool is controlled by a comparator which determines the exact depth of the prisms and produces an engraving in a section of 500 mm length so as to allow a horizontal excursion controlled by stops which determine the pitch of the new prisms which are to be coined onto the methacrylate. According to the present invention, prisms 2 realized onto the methacrylate bars M may be of different kinds, according to the amplitude of the light emission to be obtained. Even if - in theory - it is possible to realize workings which may obtain emissions until 1 80° amplitude, the industry produces two kinds of prisms, which determine respectively the amplitude of 30° and 56°: - for the emission angle of 30°, the prisms are obtained by means of a miller with 1 25 mm diameter and forty theeth; the advancing of the miller takes place with a linear movement, touching the surface of t h e methacrylate bar, as shown in figure 3, so as t o determine a prism-like engraving with 1 ,25 mm depth and 1 2 mm length; the faces of the obtained prism are at an angle of 95° and the pitch is of 3 mm, as such angle allows the light beam introduced into the optic conductor to be totally reflected inside the same , acocrding to angles contined in the limit, total internal reflection angle, and such as to allow the emission according to a beam emission of 30° from the conductor section opposite to the worked one; or the 56° emission angle, the prisms are obtained by means of a miller with 125 mm diameter and forty teeth; the advancing of the miller takes place with a revolution movement around the methacrylate bar, as shown in figure 4, such as to determine a prism-shaped engraving onto a circular section, 1 ,25 mm deep and 19,1 mm long, so that said angle allows the light beam introduced into the optic conductor to be totally reflected inside the same according to angles contained in the internal total reflection limit angle and such as to allow the emission according to a beam angle of 56° from the section of the conductor opposite to the worked one.

Claims: CLAIMS 1. A process for the cold-realization and hot-coinage of prisms onto methacrylate optic conductors, and derived products, characterized in a cold-working which comprises one or more constant pitch millers ( 1 ) for the realization of a plurality of parallel specular prisms (2) with a perfectly plane and bright surface, engraved onto the surface of the optic methacrylate conductor (M); or by hot-working, with a tool consisting of a copper parallelepiped, inside crossed by resistances and thermostats which allow a controlled heating, and of an engraving area that coins the micro-prisms onto the bar, the ends whereof are then perfectly polished with a grinding- wheel. 2. A process according to claim 1 , characterized in that it is performed onto a vertical working centre with a useful run of 1 .300 mm and with a reference system that may move the methacrylate bar (M) without errors of replacing, allowing to work also onto bars longer than the machine's run, and onto which an angular head of 90° is mounted which allows a cold-working with a disc miller (1 ) and polished with a cbn (borazon) grinding-wheel, and then with a circular saw with a diameter of 1 25 mm, modified at 100°, for allowing a wall of parallel optic prisms (2), realized onto a bar (M), as specular as possible. 3. A hot-working process according to claim 1 , characterized in that the methacrylate bar (M) is placed onto a tool- carrying structure (D), fixed to the base (B) by means of supports (4) for allowing the contact with said bar and the vertical sliding of the tool. 4. A hot-working process according to claim 1 , characterized in that the vertical descent of the tool is controlled by a comparator which determines the exact depth of the prisms and produces an engraving in a section of 500 m m length so as to allow a horizontal excursion controlled by stops which determine the pitch of the new prisms (2) which are to be coined onto the methacrylate (M). 5. A product derived by the process according to claim 1 , characterized in prisms (2) with an emission angle of 30° obtained by means of a miller with 1 25 mm of diameter and forty teeth, with a linear movement advancing of the miller (1 ) touching the surface of the methacrylate bar, so as to determine prism-shaped engravings with 1 ,25 mm depth and 1 2 mm length and with the faces of each prism at a 95° angle and with a pitch of 3 mm. A product derived from the process according to claim 1 , characterized in prisms (2) with a 56° emission angle, realized by means of a miller with a diameter of 125 mm and forty teeth, and with a revolution movement advancing of the miller around the methacrylate bar (M) so as to determine a prism-shaped engraving onto a circular section, with 1 ,25 mm depth and 19, 1 mm length.

Inventors: DE SISTI FABIO, DE SISTI, FABIO
Applicants: SISTI FABIO DE, SISTI LIGHTING S P A DE, DE SISTI LIGHTING S.P.A., DE SISTI, FABIO
Application year: 1998
Main classification: G02B5
IPC codes: B23C3, B29C59, B29D11, F21V8, G02B5, G02B6