MXPA99007501A - Apparatus for generating parallel radiation for curing photosensitive resin - Google Patents

Abstract

An apparatus of parallel radiation for curing a resin to produce a resinous framework of a papermaking belt is provided. The apparatus comprises a source of radiation (20) and an elongate reflector (30) having an outer surface (32), an inner surface (31), a longitudinal axis (37), and two ends spaced apart along the longitudinal axis (37). The inner surface is comprised of a plurality of reflective facets (35) oriented parallel to the longitudinal axis (37). In its cross section, the reflector (30) has a concave shape having a cross-sectional axis (33) perpendicular the longitudinal axis. The reflective facets (35) have a common focal point (F) in the cross section. The reflective facets (35) direct radiation substantially parallel to the cross-sectional axis (33). Preferably, the plurality of reflective facets (35) form the reflector's inner surface (31) having a parabolic or circular macro-scale shape in the cross section.

Description

APPARATUS FOR GENERATING A PARALLEL RADIATION FOR THE CURING OF PHOTOSENSIBLE RESIN FIELD OF THE INVENTION The present is related to processes for manufacturing papermaking bands, which comprise a reinforcement structure attached to a resinous framework. More particularly, the present invention relates to an apparatus for curing a photosensitive resin to produce the resinous reinforcement of a band for the manufacture of paper, the apparatus generates a reflected radiation in a practically parallel manner.

BACKGROUND OF THE INVENTION Paper products are used for a variety of purposes. Paper towels, disposable tissues, toilet paper and the like are in constant use in modern industrialized societies. The high demand for these paper products has created the demand for improved versions of the products. In general, the paper manufacturing process includes several steps. An aqueous dispersion of the paper fibers is transformed into an embryonic web on a foraminate member, such as. example a Fourdrinier mesh or a twin mesh paper machine, in P875 where the initial dewatering and the rearrangement of the fibers occurs. In a through-air drying process, after initial dewatering, the embryonic web is transported to a pass-through drying band comprising an air-permeable deflection member. The deflection member may comprise a resinous armature having a pattern or mold, which has a plurality of deflection conduits through which air can flow under a differential pressure. The resinous armature is attached to a woven reinforcement structure and extends outwardly therefrom. The papermaking fibers of the embryonic web are flexed or deflected into the deflection conduits and the water was removed through the deflection conduits to form an intermediate web. The resulting intermediate web is then dried in the final drying step, in which the portion of the web in register with the resinous web can be subjected to printing to form a multi-region structure. The papermaking webs for air-pass drying comprising a reinforcing structure and a resinous reinforcement are described in United States Patent Serial No. 4,514,345 issued to Johnson et al. on April 30 P875 1985; U.S. Patent No. 4,528,239 issued to Trokhan on July 9, 1985; U.S. Patent No. 4,529,480 issued to Trokhan on July 16, 1985; U.S. Patent No. 4,637,859 issued to Trokhan on January 20, 1987; U.S. Patent No. 5,334,289 issued to Trokhan et al on August 2, 1994. The foregoing patents are incorporated herein by reference for the purpose of showing preferred web constructions for the manufacture of paper for drying with through air. These bands have been used to produce commercially successful products, such as Bounty paper towels and Charmin Ultra toilet paper, both produced and sold by the present assignee. Presently, the resinous armor of a band for the manufacture of paper for the drying with passing air is manufactured by processes that include the curing of a photosensitive resin with UV radiation, in accordance with a desired pattern or pattern. The United States Patent assigned jointly, No. 5,514,523, granted on May 7, 1996 to Trokhan et al. and incorporated herein by reference, discloses a method for manufacturing the web for papermaking using differential light transmission techniques. In order to manufacture this band, a coating is applied to the reinforcement structure.

P875 liquid photosensitive resin. Then, a mask in which opaque regions and transparent regions define a preselected pattern or model, it is placed between the coating and a radiation source, such as UV light. The curing is carried out by exposing the liquid photosensitive resin coating to the UV radiation coming from the radiation source, through the mask. The curing UV radiation passing through the transparent regions of the mask, cure (i.e., solidify) the exposed areas to form knuckles extending from the reinforced structure. The unexposed areas (ie, the areas corresponding to the opaque regions of the mask) remain fluid, that is, not cured, and will subsequently be removed. The angle of incidence of irradiation has an important effect on the presence or absence of inclination in the walls of the conduits of the band for the manufacture of paper. The radiation that has a greater parallelism produces duct walls with less inclination or inclination (or almost vertical walls). As the ducts become more vertical, the papermaking band has a greater air permeability, to a certain knuckle area, with respect to a papermaking band having more sloping walls.

P87S Common devices for curing resin produce papermaking belts comprising the reinforcing structure and the resinous reinforcement include a radiation source (i.e., a light bulb) and a reflector having an elliptical shape. The bulbs of commonly used appliances need microwave energy to function. The elliptical shape for the reflector has been chosen, because the elliptical shape and its accompanying volume help to maximize the coupling of the microwave energy necessary for the bulbs to operate in the most efficient way. While the elliptical shape of the reflectors of the prior art is efficient with respect to the microwave coupling, the elliptical shape of the reflector generates non-parallel and very off-axis or "scattered" radiation rays. The elliptical shape is thus inefficient for the curing of the photosensitive resin comprising the framework. Until now, equipment manufacturers have not been able to design a reflector that maximizes microwave energy and, at the same time, generates parallel radiation for more efficient curing of the resin. In some cases, space limitations can also influence the shape of the reflector. Therefore, a means is required to control the angle of incidence of the curing radiation independent of the geometry of the reflector.

One of the means to control the angle of incidence of the radiation is a subtractive collimator. The subtractive collimator is, in effect, an angular distribution filter that blocks the rays of UV radiation in other directions than desired. A common subtractive collimator comprises a dark colored metallic device, formed in the form of a series of channels through which the light rays can pass in the desired direction. U.S. Patent No. 5,514,523 cited above and incorporated herein by reference, discloses the method for manufacturing a papermaking web using the subtractive collimator. While the collimator. Subtractive helps to direct the radiation rays in the desired direction, the total energy of radiation reaching the photosensitive resin to be cured is reduced, due to the loss of radiant energy in the subtractive collimator. Therefore, it is an object of the present invention to provide an improved apparatus for curing a photosensitive resin and producing a papermaking band having the resinous armature, this apparatus significantly reduces curing energy losses. It is also an object of the present invention to provide an apparatus for curing a photosensitive resin, the apparatus generates practically parallel curing radiation. It is a further object of the present invention to eliminate the mutual influence or interdependence, between the shape of the reflector and the optical conditions that produce the reflected radiation in parallel, ie, to decouple the shape of the reflector from its optical effect.

SUMMARY OF THE INVENTION The apparatus for generating the parallel radiation of the present invention can be used to cure a resin and produce the resinous reinforcement of a band for the manufacture of through-air drying paper. The apparatus comprises a radiation source and an elongated reflector having an external surface and an internal surface. The reflector also has a longitudinal axis and two ends spaced in longitudinal direction parallel to the longitudinal axis. The cross section of the baffle has a concave shape having a cross sectional axis perpendicular to the longitudinal axis. The internal surface of the reflector is comprised of a plurality of reflective facets oriented in the longitudinal direction. In the cross section of the reflector, the reflective facets have a common focal point, preferably located on the cross section axis. In a preferred embodiment, the inner surface comprised of the plurality of reflecting facets have a macroscopic essentially parabolic shape in cross section. In another preferred embodiment, the internal surface of the reflector comprised of the plurality of reflective facets has a macroscopic shape essentially circular in a region for axial cross section. Reflective facets can be integrated. Alternatively, the reflecting facets may be attached. The source of radiation, preferably an elongated bulb, is oriented in the longitudinal direction and juxtaposed with, and preferably located at, the common focal point of the cross section. In cross-section, the plurality of facets directs most of the radiation rays reflected in a direction substantially parallel to the cross-sectional axis. A liquid photosensitive resin, radiation curable and having a surface oriented towards radiation, is located in the direction of. the radiation. A reinforcing structure is located in the direction of the radiation and adjacent to the liquid resin, which will be attached to the resinous reinforcement when the resin is cured. Preferably, the surface of the radiation-oriented resin is generally perpendicular to the axis of the reflector. A mask, which has opaque regions and transparent regions that define a preselected pattern, is placed between the radiation source and the resin surface facing the radiation. A collimator, preferably a subtractive collimator, can be located intermediate to the radiation source and to the surface of the resin oriented towards the radiation.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of the apparatus of the present invention. Figure 2 is a schematic cross-sectional view of the apparatus shown in Figure 1, showing a reflector having a plurality of integrated reflective facets and also showing a bath containing the liquid photosensitive resin and the reinforcing structure that will be enclosed in the resin. Figure 3 is a schematic cross-sectional view of the apparatus comprising an elliptical reflector of the prior art. Figure 4 is a schematic cross-sectional view showing the comparison of a circular mirror and a parabolic mirror.

Figure 5 is a schematic cross-sectional view similar to that shown in Figure 2 and showing a plurality of attached reflector facets, mounted on a frame attached to the reflector; Figure 6 is a schematic cross-sectional view of the apparatus; of the present invention, comprising a reflector having an essentially planar geometric cross-section and an inner surface comprised of a plurality of reflective facets having a common focal point.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows in schematic form an apparatus for generating the parallel radiation 10 of the present invention. The apparatus 10 can be used to cure a photosensitive resin used to produce the resinous armor of the bands for the manufacture of through-air drying paper. The apparatus 10 of the present invention comprises two primary elements: an elongated reflector 30 and a radiation source 20. As illustrated in Figure 1, the elongated reflector or, simply, the "reflector" 30, has a longitudinal axis 37 and a pair of ends: a first end 34 and a second end 36. The "longitudinal axis 37" will be defined later. Ends 34 and 36 are mutually opposed P875 and separated from each other in the longitudinal direction. As used herein, the "longitudinal direction" is any direction parallel to the longitudinal axis 37 of the reflector 30. Figure 2 shows that the reflector 30 has a concave cross section. The concave cross section of the reflector 30 has a cross-sectional axis 33. As used herein, the cross-sectional axis 33 is an imaginary straight line with respect to which, the cross section of the concave reflector 30 is bilaterally symmetrical . The cross-sectional axis 33 is perpendicular to the longitudinal axis 37. Those skilled in the art will recognize that an imaginary cross-sectional plane is also perpendicular to the longitudinal axis 37. The reflector 30 has an internal surface 31 and an external surface 32. The surface external 32 may comprise a frame and mounting means for the reflector 30. The internal surface 31 is the reflector surface of the reflector 30. The internal surface 31 is comprised of a plurality of reflective facets 35 oriented in the longitudinal direction. Each reflective facet 35 has its own reflecting surface 35a. Observed in transverse direction, the reflecting facets or, simply, the "facets" 35 are located or arranged in such a way that the facets 35 have a common focal point "F", P875 as illustrated in Figure 2. As used herein, the term "common focal point" or "common focus" "F" defines the point in cross section, at which point most of the rays reflected from facets 35 converge or intersect, if these reflected rays are created by the reflection of the rays parallel to the axis of cross section 33. This situation is not illustrated but can be • easily visualized by inverting the directions of the directional arrows D (direct rays) and R (reflected rays), which schematically represent the rays in Figure 2. Preferably, the focus F is juxtaposed to the axis of cross section 33. More preferred, the focus F 'is located on the axis of cross section 33. In accordance with the law of reflection, if the direction of a reflected beam ee reverses, the reflected beam will geometrically match the original direct input beam but, will have direction opposite. Paul A. Tipler, Physics, p. 646, Copyright ® 1976 by Worth Publishers, Inc. This book is incorporated herein by reference for the purpose of describing the law of reflection. Therefore, the common focus F, in other words, is a point at which the radiation source 20 must be located in order to cause the original direct rays D generated by the radiation source 20 to be reflected from the facets 35, in such a way that the rays P875 R are substantially parallel to the axis of cross section 33. This situation is illustrated in Figure 2. Now, the longitudinal axis 37 can be defined as an imaginary line running through the common focal point F and perpendicular to the section plane imaginary cross Preferably, the longitudinal axis 37 is generally parallel to the internal surface 31 of the reflector 30. Preferably, the plurality of the facets 35 form the internal surface 31 having a cross-sectional configuration comprising a macroscopic essentially parabolic or circular shape. For the purposes of the present invention, the difference between the macroscopic parabolic shape and the circular macroscopic shape is essentially indistinguishable, as will be explained below. It should be noted that in the present application, references to the "cross-sectional axis", "common focal point", shape of the inner surface 31, direct rays D, reflected rays R and similar elements that are particularly relevant when viewed in section transverse, normally should be considered in the context of the cross section shown in Figures 2, 3, and 4, unless otherwise indicated. As used herein, the terms "essentially circular macroscopic shape" or "form P875 essentially parabolic macroscopic ", indicate a total cross-sectional shape of the inner surface 31 of the reflector 30, when the cross section of the inner surface 31 is observed or considered as a whole with respect to its optical effect. even if the overall geometrical cross-sectional shape of the inner surface 31 is not "essentially parabolic / circular", the inner surface 31 may still have the essentially parabolic / circular macroscopic shape (i.e., the inner surface 31 can still function as if However, this does not exclude the internal surface having an essentially parabolic / circular geometric shape in cross-section, and it must also be recognized that deviations from the total absolutely spherical or parabolic form are tolerable, although they are not preferred, as long as the deviations are not important enough to adversely affect the performance of the reflector 30. Similarly, it should be recognized what possible transition areas between two or more adjacent facets are also tolerable, if these transition areas do not adversely affect the performance of the reflector 30. By contrast with the "macroscopic shape" in cross-section of the inner surface 31, the cross-sectional shape of the individual facet 35, P875 in particular, the shape of its reflecting surface 35a, defines a "microscopic shape" of the inner surface 31. As described above, in cross-section, the plurality of facets 35 reflects the radiation (direct rays D) of the source radiation 20, such that most of the reflected rays R are substantially parallel to the axis of cross section 33. As shown in Figure 1, the facets 35 are oriented in the longitudinal direction and are practically parallel to it (ie , the facets 35 are substantially parallel to the longitudinal axis 37). Those skilled in the art will readily understand that the number and shape of the facets 35 is dictated primarily by the desired resolution or by the fidelity of the plurality of facets 35 to the macroscopic parabolic or circular cross-sectional shape. In Figure 2, it is schematically shown that each individual facet 35 is planar (ie, having a planar reflective surface 35a). However, the facets 35 may have other shapes, for example, a curvilinear shape. Any suitable means can be used to join the facets 35 to the reflector 30, to mount the facets 35 and form the internal surface 31. For example, the facets 35 can be formed directly on the reflector 30 to be an integral part of the reflector body 35, according to P875 is shown schematically in Figure 2. These reflective facets 35 are "integral or integrated" facets and can be formed during a molding operation, mechanically or by any other method known in the art. Alternatively, as shown in Figure 5, the facets 35 may be mounted on a frame or housing 39, which may or may not have a global parabolic or circular / parabolic shape in cross section and the frame itself could be attached to the reflector 30. The reflector 30 may have a plurality of individual housings therein, each individual housing receiving each individual facet 35. These facets 35, either mounted on the frame 39 or individually joined to the reflector 30, are "attached" facets. It should be understood that the reflector 30 can have both types of facets 35: integrated and attached. The combination of the above means for forming and / or joining the facets to the reflector 35, as well as other means known in the art, may be feasible for the present invention. When the common focal point F is located on the cross-sectional axis 33, the cross-sectional axis 33 coincides with the optical axis of the parabolic or circular macroscopic shape of the internal surface 31 created by the plurality of reflective facets 35. The experienced ones in the art you will recognize that parallel paraxial rays P875 are normally reflected from a concave spherical mirror (ie, circular cross section) through the focal point, which is located on the optical axis of the mirror at a distance equal to half the radius of the mirror from the mirror surface . idem. , p . 645-646. As used herein, paraxial rays are those direct rays D generated by the radiation source 20 that arrive at comparatively shallow angles with respect to the optical axis or axis 33 of the reflector 30. Figure 4 illustrates what is meant by the term "paraxial rays". In Figure 4, the symbol "S" designates a circle (circular mirror) that has its center at point "C" and its origin at point "A". The symbol "P" designates a parabola (parabolic mirror) that has its focus at point "F" and its vertex at point "A". As illustrated in Figure 4, parabola P and circle S have very close (in fact, almost indistiguous) forms between points "Pl" and "P2". Beyond these points Pl and P2, the respective significant deviations of the forms of the parabolic mirror P and the circular mirror S begin. The subtended region defined by the lines interconnecting the points P1 - C - P2 is a " paraxial region "that is, the region in the immediate vicinity of the common optical axis of circle S and of parabola P, where the configuration of circle S and the configuration of the parabola P875 P are essentially indistinguishable for all practical purposes. The direct rays D that are within the paraxial region are the paraxial rays. Eugene Hecht, Optics, Second Edition, page 159, Copyright ® 1987, 1974 by Addison-Wesley Publishing Company, Inc. This book is incorporated herein by reference for the purpose of showing the comparison (graphical and mathematical) of parabolic mirrors and of particular mirrors. It should be noted that while Tipler and Hecht use a definition of "spherical mirror", the Applicant considers that in the present Application, especially in the context of the cross section, the definition "circular mirror" is more precise and more consistent with the definition of "parabolic mirror", the two figures, the "parabola" and the "circle", are plane geometric figures. As used herein, the term "circular mirror" includes a mirror, the cross section of which is formed by a circular arc of up to 180 degrees. However, it should be understood that three-dimensional spherical mirrors and three-dimensional paraboloid mirrors are also included in the scope of the present invention. In accordance with the present invention, in the paraxial region of cross section, the inner surface 31 formed by the plurality of reflective facets 35 has either a circular macroscopic shape or a macroscopic parabolic shape. External to the region Paraxial P875, inner region 31 has a macroscopic parabolic shape. In accordance with the present invention, the radiation source 20 is elongated in the longitudinal direction (Figure 1) and is preferably juxtaposed to the common focus F in cross section (Figure 2). More preferably, in cross-section, the radiation source 20 is located in the common focus F located on the cross-sectional axis 33- As shown above, when the radiation source 20 is located in the common focus F of the cross section, the concave reflector 30 directs the radiation emitted from the radiation source 20 and reflected from the plurality of facets 35 in a direction substantially parallel to the axis of cross section 33. The preferred radiation source 20 is an elongated exposure lamp or light bulb which extend between the first end 34 and the second end 36 of the reflector 30 and parallel to its longitudinal axis 37. Observed in cross section, the radiation source 20 emits UV rays in the directions indicated schematically by the directional arrows D ( direct rays) and R (reflected rays of Figure 2. The radiation source 20 is selected to supply primary radiation. mainly within the wavelength which causes the curing of a liquid photosensitive resin 43 to produce a resinous armature 48. That length of P875 wave is a characteristic of liquid photosensitive resin 43. As described above, when liquid photosensitive resin 43 is exposed to radiation of the appropriate wavelength, curing is induced in the exposed portions of resin 43. Curing It is usually manifested by the solidification of the resin in the exposed areas. Conversely, the unexposed regions remain fluid and will be removed after this (e.g., by trawl washing). Any suitable curing radiation source 20 may be used, such as mercury arc lamps, pulsed xenon lamps, without electrode and fluorescent lamps. The intensity of the radiation and its duration depends on the degree of curing required in the exposed areas. The absolute values of the intensity and time of exposure depend on the chemical nature of the resin, its photosensitivity characteristics, the thickness of the resin coating and the selected pattern. For the preferred resin, Merigrafh resin EPD 1616, this amount varies from about 100 to about 1,000 milijoules / cm2. For comparison, Figure 3 schematically shows the cross section of a prior art apparatus 100 for curing resin. The prior art apparatus 100 comprises a reflector 130 having a P875 elliptical inner surface 131 and a radiation source 120 located on an axis 133 of the reflector 130. The rays coming from the radiation source 120 are reflected from the elliptical surface 131 and converge at the point Fl. The reflected rays are then separated and most of the reflected rays collide with the subtractive collimator 47 which blocks a large amount of the reflected rays. It is estimated that in the existing apparatus 100, more than 50% of the total energy received by the resin being cured is reflected energy. Therefore, the elliptical shape of the reflector 130 of the prior art causes a significant loss of the total curing energy, due to the significant loss of energy reflected in the collimator. In contrast to the apparatus 100 of the prior art, in the apparatus 10 of the present invention, most of the reflected rays R are substantially parallel to the cross-sectional axis 33 and, therefore, neither converge / diverge before reaching the surface 45 facing the radiation of the resin 43. Consequently, most of the reflected rays R pass through the collimator 47 without being blocked by it and without losing excess energy. The collimator 47 is optional and can still be used to block scattered rays, especially direct rays scattered from the radiation source 20, which have other directions than those desired.

P875 As indicated in the background of the invention, the elliptical shape of the reflector 130 of the prior art can be essential to maximize the amount of energy necessary for the effective operation of the bulbs used in the existing apparatus 100. But at the same time, the elliptical shape of the reflector 130 of the prior art can not produce the desired parallel reflected rays. The present invention combines the geometrically elliptical shape of the reflector 30 with the optically macroscopic parabolic or circular shape of the inner surface 31 of the reflector 30. Thus, the present invention effectively eliminates the interdependence between the microwave energy essential for effectiveness of the radiation source 20 and the parallel radiation essential for the effectiveness of the curing process.

In other words, the apparatus of the present invention effectively decouples the geometrical cross-sectional shape of the reflector 30 from the optical effect of the reflector. Also, space restrictions can prevent a manufacturer of equipment from manufacturing a reflector having a geometrically parabolic or circular cross-sectional shape. Still, by eliminating the interdependence between the geometric shape of the reflector 30 and the optical effect of the reflector, the apparatus 10 of the present invention generates a parallel radiation without considering the particular overall shape P875 in cross section of the reflector 30. As an example, Figure 6 shows the reflector 30 having a geometric cross-section practically flat (as opposed to the concave). However, the inner surface 31 comprised of the plurality of reflective facets 35 having the common focus F has, in accordance with the present invention, a macroscopic parabolic or circular shape, as already explained above. Figure 2 illustrates schematically an arrangement in which the photosensitive resin 43, curable by the radiation of the apparatus 10, is located in a bath '40. The radiation-oriented surface 45 of the photosensitive resin 43 is practically perpendicular to the direction of the reflected rays R. This arrangement makes it possible to produce the armature 48 having ducts with walls that essentially bilaterally are symmetrically inclined. A reinforcing structure 50 is placed in the bath 40 filled with liquid photosensitive resin 43. During curing (ie, solidification) of the resin 43, the reinforcing structure 50 is attached to the resinous armature 48 or is encased therein. The same, which is comprised by the cured resin 43. In Figure 2, the dashed lines 44 indicate schematically what will be the walls of the ducts of what will be the resinous framework 48 comprised by the cured resin 43.

P875 The mask 46 having opaque regions 46a and transparent regions 46b with a preselected pattern is placed between the radiation source 20 and the radiation-facing surface 45 of the photosensitive resin 43. Preferably, the mask 46 is in a contacting ratio with the radiation-oriented surface 45 of the photosensitive resin 43. Alternatively, the mask 46 can be positioned at a finite distance from the radiation-facing surface 45 of the resin 43. The mask can be fabricated from any suitable material that can be provided with opaque regions 46a and with transparent regions 46b. While the preferred subtractive collimator 47, placed between the mask 46 and the radiation source 20 is shown in Figure 2, additional or alternatively other means can be used to control the direction and intensity of the curing radiation. Other means for controlling the intensity and direction of curing radiation include refractive devices (ie, lenses) and reflective devices (ie, mirrors). Although the arrangement shown in Figure 2 includes the bath 40 containing the liquid photosensitive resin 43 and the reinforcing structure 50, other arrangements utilizing the apparatus 10 of the present invention may be feasible and even preferred. A preferred example is a process Continuous P875, disclosed in the United States Patent, assigned jointly, No. 5,514,523, referred to above. In the continuous process, to the reinforcing structure 50, which preferably comprises a loop or endless cycle, a coating of a liquid photosensitive resin is preferably applied. Also, in the continuous process, the mask 46 preferably comprises a loop or endless cycle traveling in the same direction as the loop of the reinforcing structure 50. The photosensitive resins and suitable antioxidants are described in the above Patent 5,514,523, incorporated by reference herein. The apparatus 10 of the present invention can be used to cure the photosensitive resin 43 to produce different types of the resinous armature 48. For example, U.S. Patent No. 4,528,239 and U.S. Patent No. 4,529,480, before referred, reveal to the armor that has an essentially continuous network. At the same time, the United States Patent, assigned jointly, No. 5,245,025 granted to Trokhan et al. on September 14, 1993 and U.S. Patent No. 5,527,428 issued to Trokhan et al. on June 18, 1996, they reveal the armor comprised by a pattern arrangement of protuberances. The above patents are incorporated herein by reference with P875 in order to show different types of the armature 48, which could be produced using the apparatus 10 of the present invention.

P875

Claims (10)

1. CLAIMS: 1. An apparatus for curing a photosensitive resin, the apparatus comprising: a radiation source; and an elongated reflector having a longitudinal axis, two ends spaced in the longitudinal direction parallel to the longitudinal axis and a concave cross section having a cross sectional axis perpendicular to the longitudinal axis, the reflector further has an internal surface and an external surface, the inner surface comprises a plurality of reflective facets oriented longitudinally and parallel to it, the reflective facets have a common focal point in cross section to direct radiation in a manner substantially parallel to the axis of cross section, the radiation source is oriented in longitudinal direction and juxtaposed to the common focal point in cross section. The apparatus according to claim 1, wherein the common focal point of the reflecting facets is located on the cross sectional axis of the reflector and the radiation source is located at the focal point of the cross section. 3. The apparatus according to claim 1 or 2, wherein the radiation source comprises a light bulb P875 elongated located between the first end and the second end of the reflector and parallel to the longitudinal axis of the reflector. The apparatus according to claims 1, 2 or 3, wherein the inner surface of the concave reflector has a macroscopic parabolic shape in cross section. The apparatus according to claims 1, 2 or 3, wherein the inner surface of the concave reflector has a circular macroscopic shape in a paraxial region of the cross section. The apparatus according to claims 4 or 5, wherein the plurality of reflecting facets comprise planar reflecting facets. The apparatus according to claims 4 or 5, wherein the plurality of reflecting facets comprise curvilinear reflective facets. 8. The apparatus according to claim 6 or 7, wherein the reflective facets are faceted or integrated facets. 9. An apparatus for curing a photosensitive resin, the apparatus comprising: a source of radiation; and an elongated reflector having a longitudinal axis, two ends separated in the direction P875 longitudinal parallel to the longitudinal axis and a concave cross section having a cross sectional axis perpendicular to the longitudinal axis, the reflector further has an internal surface formed by a plurality of reflective facets oriented in the longitudinal direction and an external surface, the inner surface has a macroscopic shape practically parabolic in cross section to direct the radiation practically parallel to the axis of cross section, the radiation source is oriented along the longitudinal axis. 10. An apparatus for curing a photosensitive resin, the apparatus comprising: a source of radiation; and an elongated reflector having a longitudinal axis, two ends spaced in the longitudinal direction parallel to the longitudinal axis and a concave cross section having a cross sectional axis perpendicular to the longitudinal axis, the reflector further has an internal surface and an external surface, the inner surface is formed by a plurality of reflective facets oriented in the longitudinal direction and has a common focal point in cross section to direct the radiation substantially parallel to the axis of cross section, at least part of the internal surface has a macroscopic shape practically Circular in cross section, the radiation source is oriented along the longitudinal axis. P875