Selective illumination device.

p0001The present invention relates to a device for the selective illumination of a flat surface to highlight the projections carried by said flat surface.

p0002A typical application of such a device is the inspection of printed circuit boards with through-hole by means of a camera and an image analysis system.

p0003The device according to the invention comprises an enclosure surrounded by an opaque side wall, a plurality of optical devices along and outside of the side wall, each optical device comprising means for generating a light flux concentrated in a slightly divergent thin brush with sharp edges, which creates an internal volume of air to separate strong illumination of a dark outer zone by a clear plan.

p0004According to a exemplary embodiment, the optical device comprises means for generating a concentrated light flux directed parallel to the side wall and a total reflection prism disposed so as to have a portion of a vertical face facing a window close and to receive said focused light flux and to reflect it into a slightly divergent thin brush directed substantially parallel to a plane perpendicular to the axis of the enclosure.

p0005The invention is described in the following on an exemplary embodiment with reference to the accompanying drawings in which:<ul><li>. Figure 1 is a schematic perspective view of an exemplary embodiment according to the invention,</li><li>. Figure 2 is a sectional view along the line II-II of Figure 1.</li></ul>

p0006Referring to FIG 1 shows a device or light box according to the invention, of parallelepipedal general shape, having side faces 2 opaque. The interior of the tank is to receive an observation appliance or any inspection. The lateral surfaces 2 are advantageously mounted so as to pivot about pivots 11 (visible in Figure 2).

p0007The object of the invention is to create a thin light beam with low divergence and edges to create a high brightness diffused air volume separated from a dark area outside by a clear plan. To do this, the side faces of the tray or some of them bear extérieu larly an optical device shown in Figure 2.

p00083 on a bracket carried by the opaque surface 2 is mounted a light source 4 consists for example of several tubes aligned along the focal line of a concave reflector 5. The light source 4 is connected to an appropriate power device (not shown ). The light sources distributed on the lateral faces can be ignited individually or in groups and can be switched on permanently or splinters. Above fluorescent tubes 4 is arranged a lens 6 for condensing the luminous flux reflected by the reflector 5 in a light beam that enters a total reflection prism 7 positioned such that its vertical face slightly beyond the upper edge 21 of the opaque wall 2, a portion of the vertical face of the prism being thus facing a narrow window 8. a thin beam of light weakly divergent and sharp edges is thus directed through the narrow aperture 8 substantially parallel to the plane 9 perpendicular to the axis I of the light box 1.

p0009The light of the aforementioned thin brush does not come out the light box and high luminous intensity, combined with a constant light density on the entire light field, can create a sharp transition zone, parallel to the plane 9, which separates interior space 1 high diffuse illumination with a dark outer zone 10.

p0010The thin high-intensity light beam is able to selectively illuminate the whole outgrowth carried by one planar surface extending in the separation plane 9 above, which allows to very simply identify visually growths or sensor. Thus, for example, by placing a printed circuit board with a face situated substantially in the plane 9, the through-hole electronic components mounted on the card they are selectively illuminated so that they can be easily detected and identified by relative to the surface of the card that is yet more reflective, and may be also identified with respect to pins engaged in their housing but which do not cross the map.

p0011It is understood that the application of the device according to the invention is not limited to the field of inspection of electronic cards.