Fishing – trapping – and vermin destroying
Patent
1990-04-02
1991-08-27
Chaudhuri, Olik
Fishing, trapping, and vermin destroying
437205, 437906, H01L 2168, H01L 2158
Patent
active
050432966
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention is directed to an assembly process for producing LED rows, particularly for the character generator of a non-mechanical printer.
What is usually meant by LED rows is the arrangement of LEDs, i.e. of light-emitting diodes in row form. Originally, discrete individual components were assembled to form rows. A coarse grid of, for example, 1/10, 1/20 inches of completely encapsulated LEDs could only be realized therewith. Later, individually unencapsulated LED chips were assembled to form rows; significantly finer grids could be realized therewith. At present, integration on the semiconductor wafer makes it possible to arrange LEDs with an extremely high dot density, for example, 300 or 600 dpi (dots per inch).
Due to limitations in the semiconductor wafer size and for reasons of yield, it is only possible to manufacture smaller strip sections of LED rows integrated in such fashion. In order to manufacture long LED rows, for example, for printing purposes, a plurality of such sections must be assembled fitting very exactly to one another.
LEDs are usually employed for display purposes. DE-A 35 34 338, for example, also already discloses, however, to employ LEDs for printing purposes in a character generator for a non-mechanical printer. The character generator disclosed therein contains a plurality of light sources fashioned, for example, as light-emitting diodes in an illumination row. A latent, electrostatic image is produced on a transfer-printing drum upon employment of the light sources. In the known character generator, all of the components that form the illumination row such as the light-emitting diodes, the drive circuits and leads, are firmly mounted on a shared carrier, whereby the fastening of the light-emitting diodes and drive circuits is undertaken by gluing. The carrier thereby has a length that is at least as great as the width of the entire illumination row.
In character generators, the employment of LEDs as imaging elements requires that the strictest tolerances be observed in all three directions given the high dot density of up to 600 dpi, i.e. with respect to division spacing, trueness to line and surface planarity. On the other hand, an optimum, thermal coupling to a carrier composed of metal is required for eliminating the high dissipated heat from the LEDs. These demands, however, cannot be met without further ado in the manufacturing methods up to now. On the basis of a preceding adjustment, the gluing of LED chips onto a carrier in fact enables the required observation of strictest tolerances in all three directions; the glue, however, prevents the optimum thermal coupling required for eliminating the dissipated heat. On the other hand, a soldering of the LED chips to a metal carrier enables an optimum thermal coupling; when soldering a LED chip, however, the softening or re-melting of the soldered connection of the neighboring LED chip necessarily leads to the de-adjustment thereof.
SUMMARY OF THE INVENTION
The object of the invention is to create an assembly process for producing LED rows that, first, enables the observation of strictest tolerances in view of division spacing, trueness to line and surface planarity and, second, guarantees an elimination of the high dissipated heat from the LEDs on the basis of an optimum thermal coupling to a metal carrier.
In an assembly process of the species, this object is achieved by the method steps as follows: line form on a planar surface of an auxiliary carrier, are adjusted relative to one another and are releasably joined to the auxiliary carrier using a glue; positioned with backsides of the LED chips on a metal carrier; soldering; and
In the assembly process of the invention, in other words, the LEDs are applied onto the metal carrier via a transfer process. This transfer process enables, first, that the LEDs can be applied onto the auxiliary carrier in line-fashion with high precision in all three directions and, that, second a connection to the metal carrier that has good thermal conductiv
REFERENCES:
patent: 3658618 (1972-04-01), Gramann
patent: 3708851 (1973-01-01), Vladik
patent: 4305097 (1981-12-01), Doemens et al.
patent: 4432131 (1984-02-01), Sadamassa et al.
"Water Soluble Blister Packaging for Electrical Components", by E. G. Crosby, et al., IBM Technical Disclosure Bulletin, vol. 16, No. 6, Nov. 1973, p. 1749.
"High-Accuracy Die-Bonding Technology for LED Array", by Hiroshi Tanabe, et al., IEEE Transactions of Components, Hybrids & Manufacturing Technology, Dec., 1985, No. 4, New York, pp. 500-504.
Hacke Hans-Jurgen
Maier Manfred
Unger Gregor
Wirbser Oscar
Chaudhuri Olik
Graybill David E.
Siemens Aktiengesellschaft
LandOfFree
Method of manufacturing LED rows using a temporary rigid auxilia does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing LED rows using a temporary rigid auxilia, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing LED rows using a temporary rigid auxilia will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1413933