Light emitting diode array and method of manufacturing

0001The invention relates to a light-emitting diode array having a plurality arranged in a matrix of rows and columns of light emitting diodes, with a dome-shaped housing having a top side and provided with a base plate are led out of the terminal pins are. The invention further relates to a method for Preparation of light-emitting diode array, and a use of Light diode array for generating an illumination of a plane Surface.

0002Light diode array of the type mentioned for illumination purposes known. They are used with simple and inexpensive, in their luminous intensity LEDs limited a relatively high to produce light intensity in which the light of the plurality of Light-emitting diodes is used, for example to an area to illuminate. The advantage of such light diode array consists that LEDs are easily controllable and high have life, by switching on and off is not impaired. With the known light-emitting diode arrays is a lighting problem then realized when only arrives to the broadcasting of a certain amount of light, wherein certain irregularities have to be accepted.

0003A precision lighting with a high uniformity of Illumination fails because the light-emitting diodes, which by Soldering be connected to a control board, after Soldering are not exactly aligned. It is known that individually employ light-emitting diodes in a housing and thereby exact alignment to allow. This arrangement has, however, the disadvantage that the LEDs in this case only some distance can be spaced from each other, so that a high intensity of illumination is no longer accessible.

0004The present invention is thus based on the problem, a to create light-emitting diode array, both the uniform Illumination and a high illumination density possible.

0005To solve this problem according to the invention is a light emitting diode array of the aforementioned type characterized in that the LEDs with their base plates on a mounting-hole plate ring lie flat and with buckles and the connecting wires on the underside of the base plate in a corresponding Hole of the base plate protrude and in the matrix with a minimum distance are arranged to each other.

0006In the light-emitting diode array according to the invention are the light emitting diodes thus arranged virtually no distance apart, encounter So with its housing or base plates together. you are yet aligned exactly parallel to the light emitting diode array to each other, because they have their base plates on a mounting-hole plate annular surface contact. This arrangement provides the advantage that the regularly on the underside in the region the pins existing domes by regularly leaked epoxy occur the surface support and not disturb alignment of the LEDs by means of the base plates. They protrude along with the terminal pins into or through the associated hole of the mounting-hole plate so that the terminal pins on the underside of the mounting-hole plate with the associated Connections, for example on a printed circuit board, are soldered and thus the light emitting diode array is attached. This ensures that all LEDs maintaining the desired angle and not by different Beam resulting unevenness occur.

0007The inventive light-emitting diode array allows first precision illuminations with high uniformity. Accordingly, in which light-emitting diode array according to the invention it be useful, that the LEDs in rows connected in series to each other are in rows and controllable in brightness.

0008This embodiment of the invention is particularly useful, when the light emitting diode array for generating an oblique incident Lighting a flat surface used such is noted that the problem in each row LEDs a have the same distance to the surface, wherein the rows of the LEDs with increasing distance from the surface of increasingly be brightened.

0009In this way can be carried with an oblique incident light the light diode array a the oblique incident light compensating uniform illumination of a field of the planar surface to accomplish. Such an arrangement is particularly useful for the examination of a surface for the presence of Error with a dark field illumination in which a regularly oblique incident light with a camera monitoring by means of a Matrix camera is substantially perpendicular to the surface stands. can through the line at a controlled brightness for all possible angle of the LED arrays for illuminated surface uniform intensity of the Surface reflected radiation can be achieved.

0010The orientation of the light-emitting diodes may thereby yet stabilized be that the dome-like tops of the LEDs in holes an upper perforated plate project. This achieves a parallel Alignment of the LEDs. If, according to one preferred Embodiment, at least the points towards the mounting plate surface and preferably also the insides of the holes of the upper Perforated plate absorbing the radiation of the light-emitting diodes is formed, the upper perforated plate the emission prevented from side lobes of the LEDs, so that by the emitted light diode array only substantially parallel radiation is because non-parallel ray absorbing the hit areas of the upper perforated plate and thus not as reflected rays can pass through the holes. In this way it is possible paralelles, smooth and flat Light with the light-emitting diode array according to the invention produce.

0011The inventive correct alignment of the LED array in the preparation of the light-emitting diode arrays by the use of the upper perforated plate ensures with their Holes aligned the dome-like tops of the LEDs and the LEDs with their base plates to the mounting-hole plate be pressed until the soldering of the pins is completed. Specifically, when the dome-like tops the LEDs with the light from the LEDs focusing Lenses are provided, it may be expedient, the upper perforated plate to left in the light-emitting diode array. However, it is also possible to remove the upper perforated plate after soldering, so that the light diode array toward the upper side by the LEDs housing is formed undisturbed. The use of the upper perforated plate causes the one hand, the correct alignment the individual light emitting diodes in parallel, since the LEDs with the dome-like tops in the associated Holes of the upper perforated plate center itself. Furthermore additionally causes the pressing of the lower lying flat Base plate of the LEDs on the perforated mounting plate that the light-emitting diodes with the centered orientation and fixed on the Mounting hole plate are resting stably fixed by soldering, so that the upper perforated plate after completion of the soldering process without disadvantages and without jeopardizing the correct alignment of the LEDs can be removed.

0012The invention will in the following with reference to a drawing in Embodiment shown in more detail. It show:<dl tsize="10"><dt>Figure 1 -</dt><dd>a schematic diagram of a section of a Light diode array</dd><dt>Figure 2 -</dt><dd>a schematic representation of radiation a light-emitting diode by an upper perforated plate therethrough.</dd></dl>

00131 shows LEDs 1, for the implementation of a dark field illumination preferably also can be infrared diodes. Each light-emitting diode 1 has a conventional, the radiation-passing Housing 2, which in itself from a base plate 3 substantially cylindrical extends upward and through a dome-shaped Buckle 4 is finished. protrude through the base plate 3 down two pins 5, which of the fixation LED 1 in respective seats, for example, Holes serve 12 a printed circuit board. 13 On the Underside of the base plate 3 are regularly in the field of the connection pins 5 protruding downwards, in the manufacture inevitable bulges 6, by leaked epoxy resin are formed.

0014The alignment of the plurality of light emitting diodes 1 parallel takes place in that the light emitting diodes 1 with its base plate 3 rest on a perforated mounting plate 7 for each Light-emitting diode 1 has a through opening 8 which is dimensioned is that the pins 5 through the hole 8 - and the bulges 6 can protrude into the hole 8 -, the base plate 3 However, on the edge of the hole 9 8 annular surface rests, namely undisturbed by the bulges. 6

0015For performing the soldering for the connection pins 5 is on the dome-shaped curvature 4 of the top of the light-emitting diodes 1 a mounting hole plate 7 resembling upper perforated plate 10 launched, which thus for each light-emitting diode 1 also has a through hole 11. Since the through hole 11 has a smaller has diameter as the housing 2 of the LED 1, extends the dome-shaped curvature of the upper surface 4 of the light-emitting diode 1 in the hole 11 in and centered there automatically when the top Perforated plate 10 exactly aligned with the mounting hole plate 7 is. The upper perforated plate 10 is mounted so that they the base plate 3 of the light-emitting diode 1 against the annular Supporting edge 9 of the mounting hole plate 7 pressed until the soldering process ends for the connection pins 5 and the light emitting diode 1 thus is permanently fixed. Thereafter, the upper perforated plate 10 be removed. The exact alignment of the LEDs 1 in the light-emitting diode array according to the invention allows uniform Illuminations, which is to simplify the interconnection of the LEDs can be useful, this line by line in series to turn and line by line controllable in brightness make, by each line of the LED arrays with a Brightness control is connected.

0016Figure 2 illustrates that conventional LEDs 1 not only a having substantially axially directed luminous maximum 14 but also obliquely radiated side lobes 15. To the Emitting diode array to achieve a possible parallel rays, it is expedient to only the radiation in the substantially axial luminous maximum exploit 14 through the opening 11 of the upper perforated plate 10 passes. The radiation the sidelobes 15 on the other hand is preferably through the upper Perforated plate 10 can not pass. For this purpose, it is advantageous when the mounting hole plate 7 facing surface 14 of the upper perforated plate 10 absorbing the radiation of the is formed light-emitting diode first