HERMETICALLY SEALED LED LIGHT AND METHOD FOR MANUFACTURING A HERMETICALLY SEALED LED LIGHT

Abstract

A hermetically sealed LED light is provided that includes a ceramic base with a plurality of LEDs and a metal cap soldered thereto and a channel for introducing an electrical, optical, or mechanical component.

Claims

1. A method for manufacturing a hermetically sealed LED light, comprising: first, assembling at least one LED on a base made of ceramic; and soldering a metal cap to the base using a metal solder.

2. The method of claim 1, wherein the metal solder comprises a gold-tin solder is used for soldering the metal cap to the base.

3. The method of claim 1, further comprising providing a window in the metal cap prior to the soldering the metal cap to the base.

4. The method of claim 3, wherein the step of providing the window comprises melting a glass into a respective channel of the metal cap.

5. The method of claim 3, wherein the metal cap and the window have coefficients of thermal expansion that differ by less than 5 ppm/K.

6. The method of claim 3, wherein the metal cap and the window have coefficients of thermal expansion that differ by less than 1 ppm/K.

7. The method of claim 1, wherein the metal cap is coated with a nickel and/or gold containing coating.

8. A method for manufacturing a hermetically sealed LED light, comprising: providing a metal cap having an end face at one end, an opening at an opposite end, and a hollow channel therebetween; melting a glass into the metal cap at the opening to form a hermetically sealed window in the opening; providing a base made of a ceramic material; disposing an LED chip on an upper surface of the base; arranging the metal cap with respect to the base so that the base is not arranged within the hollow channel but is mounted to the end face of the metal cap with the LED chip in the hollow channel; and soldering, with a solder, an outer edge of the end face and the upper surface of the base to one another to hermetically seal the metal cap and the base to one another.

9. The method of claim 8, wherein the metal cap and the window have coefficients of thermal expansion that differ by less than 5 ppm/K.

10. The method of claim 8, wherein the metal cap and the window have coefficients of thermal expansion that differ by less than 1 ppm/K.

11. The method of claim 8 further comprising arranging a converter in the hollow channel between the window and the LED chip.

12. The method of claim 11, wherein the converter is an inorganic matrix.

13. The method of claim 11, wherein the converter is silicone matrix comprising embedded fluorescent particles.

14. The method of claim 11, further comprising adhesively bonding the converter into the hollow channel.

15. The method of claim 11, wherein the step of arranging the converter in the hollow channel comprises arranging the converter as close as possible to the window.

16. The method of claim 8, wherein the window is a lens.

17. The method of claim 8, further comprising: beveling the outer edge of the end face; and arranging the metal cap with respect to the base so that the beveling of the outer edge results in a gap between the outer edge and the upper surface; and filling the gap with the solder.

18. The method of claim 8, wherein the ceramic material is made of a material selected from a group consisting of aluminum oxide, aluminum nitride, and combinations thereof.

19. The method of claim 8, wherein the metal cap is a stainless-steel metal cap.

20. The method of claim 8, wherein the solder is gold-tin solder.

21. The method of claim 8, wherein the step of melting the glass into the metal cap at the opening comprises: inserting a glass rod into the hollow channel; and melting the glass rod.

22. The method of claim 8, wherein the step of melting the glass into the metal cap at the opening further comprises forming the window with a lenticular shape due to surface tension of the glass.

23. The method of claim 8, wherein the window does not extend beyond the opposite end of the metal cap.

24. The method of claim 8, wherein the step of providing the metal cap further comprises providing a peripheral depression at the opposite end, and wherein the step of melting the glass into the metal cap at the opening comprises melting so that the window does not protrude beyond the opposite end of the metal cap.

25. The method of claim 24, wherein the step of melting the glass into the metal cap at the opening further comprises forming the window with a lenticular shape due to surface tension of the glass, wherein the lenticular shape does not protrude beyond the opposite end of the metal cap.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The subject matter of the invention will now be explained with reference to exemplary embodiments.

[0063] FIG. 1 shows a plan view of an exemplary embodiment of a hermetically sealed LED light.

[0064] FIG. 2 is a sectional view of FIG. 1.

[0065] FIG. 3 illustrates a detail of FIG. 2.

[0066] FIG. 4 shows a bottom plan view.

[0067] FIG. 5 is a schematic view illustrating the use of the hermetically sealed LED light according to the invention in conjunction with an image sensor.

[0068] FIG. 6 is a schematic view of a medical instrument with a hermetically sealed LED light according to the invention integrated therein.

[0069] FIG. 7 shows another exemplary embodiment of a hermetically sealed LED light that is not annular.

DETAILED DESCRIPTION

[0070] FIG. 1 shows a plan view of an exemplary embodiment of a hermetically sealed LED light 1 according to the invention.

[0071] In this embodiment, the LED light 1 has an annular shape. On the top, metal cap 2 can be seen which has a plurality of windows 3 through which the light from the underlying LEDs is emitted.

[0072] LED light 1 can be connected via supply line 4.

[0073] The six windows 3 illustrated in this exemplary embodiment are distributed circumferentially across the LED light 1.

[0074] Furthermore, a central channel 5 with a circular cross section can be seen, which is intended to accommodate an electrical, optical, or mechanical component.

[0075] FIG. 2 shows a sectional view of the LED light illustrated in FIG. 1.

[0076] It can be seen that the metal cap 2 which is made of a stainless steel, is cup-shaped.

[0077] A base 6 made of a ceramic material, in particular of aluminum oxide, is mounted in the cup-shaped metal cap 2 from the bottom side and is soldered to the metal cap by means of a gold-tin solder.

[0078] The plate-shaped base 6 is likewise annular, so that channel 5 extends both through the base 6 and through the metal cap 2.

[0079] Base 6 has feedthroughs (not shown), through which current for driving the LEDs is supplied to the upper side, via supply line 4.

[0080] FIG. 3 illustrates a detail of FIG. 2, namely the region in which a window 3 is arranged.

[0081] It can be seen that below window 3 the base 6 is equipped with an LED 10. LED 10 is implemented in form of a chip, in particular as a surface mounted device (SMD).

[0082] On the upper side of base 6 supply lines may be provided, for example in the form of flat conductive traces (not shown) for electrically connecting the LED 10.

[0083] As can further be seen, window 3 is provided in form of a lens.

[0084] Window 3 is arranged in a channel 7 which in turn extends through metal cap 2.

[0085] The lenticular shape of window 3 is caused by the surface tension of the glass, being produced by inserting a glass rod into channel 7 and then melting it.

[0086] At the upper end of channel 7 a peripheral depression 8 is provided.

[0087] Due to depression 8, the window 3 in form of a lens does not protrude.

[0088] Optionally, depending on the light color that is desired, a converter 9 may be arranged in channel 7. This may in particular be a converter with a silicone matrix, which is adhesively bonded into channel 7.

[0089] It can furthermore be seen that the upper surface of base 6 is soldered to the lower surface of cup-shaped metal cap 2.

[0090] The edge of base 6 is spaced from metal cap 2 in this embodiment.

[0091] By connecting base 6 and metal cap 2 by soldering and by melting the window 3 into the channel, a hermetic seal of the LED 10 is provided.

[0092] Feedthroughs in the base 6 are preferably filled with a solder as well.

[0093] For assembling the LED light according to the invention, first the metal cap is produced with the windows fused into it, and separately therefrom the base 6 is equipped with LEDs 10.

[0094] These two main components are then soldered together using a gold-tin solder that has a melting temperature below 340 C., preferably below 325 C., more preferably below 300 C.

[0095] The method of the invention is not only suitable for the annular LED light illustrated herein, but also for other types of lights, in particular lights that do not have a central channel.

[0096] FIG. 4 shows a bottom plan view of LED light 1.

[0097] Annular base 6 can be seen which in this exemplary embodiment has feedthroughs 11 and 12 via which the LEDs on the upper surface are driven.

[0098] Base 6 is embedded in cup-shaped metal cap 2.

[0099] Further, central channel 5 can be seen, in which an electrical, optical, or mechanical component may be arranged.

[0100] Supply lines 4 extend around channel 5 on the bottom surface.

[0101] It will be understood that an LED light that has a plurality of separately controlled LEDs typically will comprise more than the two feedthroughs for the positive and negative terminals as illustrated herein. That is because the driver circuits for driving the LEDs are preferably not arranged in the hermetically sealed portion of the light illustrated herein, but are rather arranged externally.

[0102] FIG. 5 schematically shows a hermetically sealed LED light 1 which, again in this embodiment, comprises an annular ceramic base 6 to which a likewise annular metal cap is soldered, which has a plurality of windows 3 through which the light from LEDs 10 radiates to the outside.

[0103] In the central channel 5, an image sensor 13 and a lens 14 is arranged.

[0104] FIG. 6 is a schematic view of a medical instrument, especially of the head piece of a dental drilling device.

[0105] A receptacle 16 can be seen, into which the drills are inserted so as to be connected to a drive shaft.

[0106] A hermetically sealed LED light according to the invention is directly mounted on the head of the medical instrument 15, and the light therefrom is directly emitted to the outside, through windows 3.

[0107] Because of the good sealing of the housing of the inventive light it is not necessary for the LED light to be arranged in the housing of the medical instrument and to guide the emitted light to the front end by means of light guides.

[0108] FIG. 7 shows an embodiment of a hermetically sealed LED light which does not have an annular configuration but was produced by the method according to the invention.

[0109] The LED light 17 comprises a base 18 made of a ceramic material, in particular aluminum oxide, to which a metal cap 19 in particular made of stainless steel has been soldered using a gold-tin solder.

[0110] The base 18 is not arranged within the cap 19 but is mounted to an end face thereof.

[0111] Metal cap 19 has a beveled edge. The solder 23 in the resulting gap provides for a better bond between the components.

[0112] Inside the hermetically sealed LED light 19, an LED 22 configured as a chip is disposed, and the light therefrom is first incident on an overlying converter 21 which is arranged below window 20 in the form of a lens.

[0113] For manufacturing this LED light 17, again, a window 20 is first produced from glass by melting the glass into the metal cap 19. Optionally, converter 21 is additionally assembled in the metal cap 19.

[0114] Then, metal cap 19 is soldered to base 18 comprising the already assembled LED 22.

LIST OF REFERENCE NUMERALS

[0115] 1 LED light [0116] 2 Metal cap [0117] 3 Window [0118] 4 Supply line [0119] 5 Channel [0120] 6 Base [0121] 7 Channel [0122] 8 Depression [0123] 9 Converter [0124] 10 LED [0125] 11 Feedthrough [0126] 12 Feedthrough [0127] 13 Image Sensor [0128] 14 Lens [0129] 15 Medical instrument [0130] 16 Receptacle [0131] 17 LED light [0132] 18 Base [0133] 19 Metal cap [0134] 20 Window [0135] 21 Converter [0136] 22 LED [0137] 23 Solder