Internal envelope infrastructure for electrical devices

Abstract

The invention relates to a housing (1) for an electrical device wherein an inner surface (2) of said housing has a conductive pattern (3) providing at least one conductive track, said track being arranged to provide local electric interconnection from the housing to at least one enclosed electrical component of said electrical device and/or vice versa, wherein the conductive pattern is fixedly fastened to said inner surface (2) of said housing so that said conductive pattern will break if the housing wall is broken where the conductive pattern is fastened.

Claims

1. An electrical device comprising: a tubular shaped housing wherein a conductive pattern, comprising at least one conductive track, is attached on an inner surface of the tubular shaped housing; a sheet arranged in the tubular shaped housing as a roll; and at least one light source comprising electrical terminals and arranged on the sheet and enclosed in the tubular shaped housing, wherein the conductive pattern is a discontinuous coating and the electric terminals of the at least one light source are electrically connected to the conductive pattern of the housing, thereby providing an electric routing for driving the at least one light source, wherein said conductive track provides a local electric bridging interconnection between the housing and the at least one light source and wherein the conductive pattern is structured such that breakage of the housing causes breakage of the conductive pattern.

2. The electrical device according to claim 1, wherein the sheet provides a spring force that presses the electrical terminals against the conductive pattern.

3. The electrical device according to claim 1, wherein the electric terminals are provided on a side of the sheet that is opposite to a side of the sheet where the at least one light source is provided.

4. The electrical device according to claim 1, wherein the at least one conductive track is a plurality of conductive tracks that are respectively disposed on the inner surface of the tubular shaped housing and wherein each conductive track of the plurality of conductive tracks is electrically isolated from each other conductive track of the plurality of conductive tracks.

5. The electrical device according to claim 4, wherein the at least one light source comprises a series of isolated light sources, each of the isolated light sources including respective electric terminals, and wherein the electric terminals of the series of light sources are aligned with and in contact with the plurality of electrically isolated conductive tracks, which form the electric routing for driving the series of light sources.

6. The electrical device according to claim 1, wherein the sheet is made of a transparent or diffuse material.

7. The electrical device according to claim 1, wherein the housing is transparent.

8. The electrical device according to claim 1, wherein the housing is made of glass.

9. The electrical device according to claim 1, wherein the housing is made of plastic.

10. The electrical device according to claim 1, wherein said conductive track is made of at least one material selected from the group consisting of: chromium, copper, silver, gold, aluminum, or a conductive composite or paste.

11. The electrical device according to claim 1, wherein said at least one conductive track(s) is arranged to provide at least one of heat-spreading or heat-sinking for said light source.

12. The electrical device according to claim 1, wherein the at least one light source is at least one LED-unit.

13. The electrical device according to claim 1, wherein the at least one light source is configured as an electrical bridge for at least one downstream light source such that any loss of electrical connection to the conductive track by the at least one light source induces a loss of power to the at least one downstream light source.

14. The electrical device according to claim 13, wherein the at least one conductive track is a plurality of conductive tracks, wherein each of the conductive tracks is electrically isolated from each other conductive track of the plurality of conductive tracks in said conducive pattern, wherein a first electric terminal of the electric terminals is directly coupled to a first track of the plurality of conductive tracks, wherein a second electric terminal of the electric terminals is directly coupled to a second track of the plurality of conductive tracks, and wherein the at least one downstream light source includes a third electric terminal that is distinct from said first and second electric terminals and is directly coupled to said second track.

15. A method for producing an electrical device comprising a housing for at least one light source comprising the steps of: discontinuously coating an inner surface of said housing with a conductive pattern coating providing at least one conductive track, wherein said conductive track is arranged to provide a local electric bridging interconnection between the housing and said light source, wherein the conductive pattern is structured such that breakage of the housing causes breakage of the conductive pattern; providing the at least one light source on a sheet; and inserting the sheet as a roll in said tubular shaped housing such that electric terminals of the at least one light source are electrically connected to the conductive pattern coating, thereby providing an electric routing for driving the at least one light source.

16. The method according to claim 15, wherein the at least one light source is configured as an electrical bridge for at least one downstream light source such that any loss of electrical connection to the conductive track by the at least one light source induces a loss of power to the at least one downstream light source.

17. An electrical device comprising: a tubular shaped housing wherein a conductive pattern, comprising at least one conductive track, is attached on an inner surface of the tubular shaped housing; a sheet arranged in the tubular shaped housing as a roll; and at least one light source comprising electrical terminals and arranged on the sheet and enclosed in the tubular shaped housing, wherein the conductive pattern is a discontinuous coating and the electric terminals of the at least one light source are electrically connected to the conductive pattern of the housing, thereby providing an electric routing for driving the at least one light source, wherein said conductive track provides a local electric bridging interconnection between the housing and the at least one light source, wherein a surface area of a side of said conductive track that provides the interconnection is larger than a light emitting surface area of said at least one light source, and wherein the conductive pattern is structured such that breakage of the housing causes breakage of the conductive pattern.

18. The electrical device according to claim 17, wherein the at least one light source is configured as an electrical bridge for at least one downstream light source such that any loss of electrical connection to the conductive track by the at least one light source induces a loss of power to the at least one downstream light source.

19. The electrical device according to claim 18, wherein the at least one conductive track is a plurality of conductive tracks, wherein each of the conductive tracks is electrically isolated from each other conductive track of the plurality of conductive tracks in said conducive pattern, wherein a first electric terminal of the electric terminals is directly coupled to a first track of the plurality of conductive tracks, wherein a second electric terminal of the electric terminals is directly coupled to a second track of the plurality of conductive tracks, and wherein the at least one downstream light source includes a third electric terminal that is distinct from said first and second electric terminals and is directly coupled to said second track.

20. The method according to claim 16, wherein the at least one conductive track is a plurality of conductive tracks, wherein each of the conductive tracks is electrically isolated from each other conductive track of the plurality of conductive tracks in said conducive pattern, wherein a first electric terminal of the electric terminals is directly coupled to a first track of the plurality of conductive tracks, wherein a second electric terminal of the electric terminals is directly coupled to a second track of the plurality of conductive tracks, and wherein the at least one downstream light source includes a third electric terminal that is distinct from said first and second electric terminals and is directly coupled to said second track.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above objects, as well as additional objects, features and advantages of the present invention, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, when taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1a is a perspective view of the housing according to the present invention having a coated conductive pattern on the inside of the housing wall.

(3) FIG. 1b is a perspective view of one embodiment of the LED-device adapted to be fitted in the housing shown in FIG. 1a.

(4) FIG. 2 is a perspective view of the LED device of FIG. 1b in the housing of FIG. 1a, where the bridging interconnection between the housing and the LED-device can be seen.

(5) As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout.

DETAILED DESCRIPTION

(6) The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

(7) FIG. 1a shows one embodiment of a housing 1 according to the present invention. The housing has a coated conductive pattern 3 on the inside of the housing wall 2. The coated conductive pattern 3 is designed to provide the missing pieces or electrical bridging to an electrical device that is inserted into the housing. The conductive pattern 3 alone thus does not provide a continuous electrical interconnection but comprises a pattern of electrically separated or isolated electrical tracks or bridges. The housing 1 in FIG. 1a is intended as a lighting device and the tube is therefore made of a transparent material, preferably glass or a clear plastic material.

(8) FIG. 1b shows one embodiment of a LED-device adapted to be fitted in the housing 1 shown in FIG. 1a. The LED-device is formed on a carrier sheet 6, wherein the sheet has a series of isolated LEDs disposed as a string 8 along its longitudinal direction. This sheet is intended to be fitted inside and along the longitudinal direction of the housing 1. A number of LEDs 5 are placed as electrically isolated units along the LED-string 8. Electrical terminals 4 provide each LED 5 in the LED string 8 with two electric contacts 7 located on the backside of the sheet, which is the side opposite to a side of the sheet 6 where the LED string 8 is placed. Alternatively, the electrical terminals of the LEDs 5 may be located on the same side of the sheet 6 as on which the LEDs 5 are provided. The electrical contacts 4 establish the electrical contact between the neighbouring LEDs by means of the conductive tracks or bridges 3 at the inside surface of the tube housing 1 in FIG. 1a. In order to establish a properly functioning electrical connection the pattern of bridges 3 and electric contacts 4 have to be aligned with respect to each other. Thus by electrically interconnecting the conductive pattern 3, which comprises a pattern of electrically separated or isolated conductive tracks or bridges, with the series of isolated LEDs a continuous electrical circuit is created comprising the series of LEDs electrically interconnected via the pattern of electrically separated or isolated conductive tracks or bridges.

(9) The side parts 9, 10 are provided to enable the insertion of the LED-string as a roll into the housing 1 and to provide a spring force that presses the contacts 4 against the bridges 3 at the inner housing wall in FIG. 1a. The roll is rolled into a, in this case, tubular shape that fits and abuts a large part of the inner wall of the housing 1. One or both side parts 9, 10 may also be made of a transparent or diffuse material, e.g., a plastic foil. Alternatively, the tube may be made diffuse. Thus, light from the LEDs may leave the tube through the transparent housing. The LED-string 8 may be placed at any lateral position on the sheet 6 so that the parts 9, 10 may have different sizes and/or properties. If the LED-string 8 is placed at the outer edges of the sheet 6 one of the side parts 9, 10 may be omitted. One of the sides 9, 10, may also be made of a diffuse reflecting material. Combined with a diffuse part 9, 10 or a diffuse glass tube and a clear part 9, 10 a diffuse recycling optical cavity may be formed when the roll is inserted into the housing 1. FIG. 2 shows the LED device of FIG. 1b in the housing 1 of FIG. 1a, where the bridging interconnection 3 between the housing and the LED-device can be seen. The terminals 4 end at the contacts 7 at the backside of the sheet 6 and are in aligned electric contact with the coated conductive pattern 3 on the inside of the housing 1, thereby interconnecting the electrically isolated LEDs unit 5 of the LED string 8 as one electric device which can be powered by connecting the conductive pattern 3 that is electrically connected to the LED string 8 to a current or voltage source. As is seen in FIG. 2, this requires that the LED-string is correctly aligned inside the housing 1. The sheet 6 preferably has a size that fills the entire length of the housing and a design of the LED-string so that the alignment between the housing and the LED device is automatically achieved.

(10) If the housing 1 is broken, part of the housing and the coating 3 will disappear along some section of the housing 1 and thus also lose its corresponding electrical connection 7 of a LED 5 of the LED-string 8 with the result that the electrical connection is lost for all LEDs. In addition, due to the expanding roll diameter, resulting in warp, other bridging connections will also be interrupted such as those of the driver to mains power supply and driver to the LED string 8. Further, a glass tube can very easily be engineered to break in many (large or small sized) fragments. A broken device will accordingly stop working and therefore provide a reduced electrical hazard.

(11) Compared to previous solutions, the above described embodiment thus eliminates a large part of the cost issues associated with electrical safety regulations by deploying a traditional glass envelope in combination with LED based light engines without compromising on electrical safety, driver isolation, costs, energy usage, optical appearance, system efficacy and manufacturing.

(12) The skilled person understands that the principle shown in the described embodiment above is easily adjusted to also provide two or more conductive patterns or conductive tracks to facilitate the same safety feature for both of the power terminals of the electrical device, in this case a LED device. It is further understood that the electrical connection between the LEDs may be in series or in parallel while using at least one or more electrical terminals with interconnection to the housing's conductive pattern.

(13) It is understood that other variations in the present invention are contemplated, and in some instances, some features of the invention can be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly in a manner consistent with the scope of the invention.

(14) Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.