Combination visible and infrared pipe

Information

  • Patent Grant
  • 6746162
  • Patent Number
    6,746,162
  • Date Filed
    Monday, July 14, 2003
    21 years ago
  • Date Issued
    Tuesday, June 8, 2004
    20 years ago
Abstract
Many device components included a printed circuit board supporting light-generating means along with a light pipe to conduct light from the light-generating means to a diffuser adjacent the surface of the components. The present invention offers an improvement whereby the light pipe can be utilized both for transmission of visible wavelengths and for transmission/reception of invisible (infrared) wavelengths. To accomplish this, a light pipe is constituted of two adjacent portions, and an infrared transceiver module is coupled into both portions.
Description




This invention relates generally to the handling of both infrared light and visible light, utilizing a single light pipe. More particularly, this invention provides a construction for a component, and a method of operation for the component, such that the function of transporting light from an optically inaccessible, light-generating location to an optically accessible region on the component can coexist with the infrared features of an appropriate transceiver device.




BACKGROUND OF THIS INVENTION




For various devices such as telephones, it is known to utilize light pipes extending from internal, optically inaccessible locations to external, optically accessible locations. Such light pipes are used to conduct visible light in products requiring visible status indicators. Typically, light pipes of this kind terminate at a light diffuser.




We have determined that it is possible to modify light pipes in such a way that status indication and infrared features can coexist within the same unit, thus leading to smaller product sizes and lower costs. These considerations are becoming increasingly important, as device portability because more desirable.




As a general principle, it is of advantage to have more integrated product designs, and also the ability to add new features to existing components.




PRIOR ART




It is known to utilize a light pipe to transfer light energy from a source such as one or more LEDs, located on a printed circuit board (PCB), up to a visually accessible surface of a product, where the light pipe typically ends at a light diffuser.




GENERAL DESCRIPTION OF THIS INVENTION




The present invention seeks to improve upon the prior art just mentioned, by allowing infrared energy and visible light to coexist and be handled within the same unit.




More particularly, this invention provides, for use with a component defining a surface, the component including a printed circuit board supporting light-generating means, along with light-transporting means for conducting light from the light-generating means to a light diffuser adjacent the surface, the improvement wherein the light-transporting means is in the form of two juxtaposed light pipe portions, and wherein an infrared transceiver module is coupled into both of the light pipe portions adjacent the light-generation means, the light pipe portions both transporting light to said light diffuser.




Further, this invention provides, in a component defining a surface and including a printed circuit board supporting light-generating means, and further including light-transporting means for conducting light from the light generating means to a light diffuser adjacent the surface, an improved method of operation wherein two juxtaposed light pipe portions transport light to said light diffuser, and where an infrared transceiver module is coupled into both of the light pipe portions adjacent the light-generating means.











GENERAL DESCRIPTION OF THE DRAWINGS




Three embodiments of this invention are illustrated in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which:





FIG. 1

is a sectioned, oblique view of a component representing the prior art;





FIG. 2

is a schematic elevation showing a major component representative of the prior art;





FIG. 3

is a further schematic diagram, useful to explain the theoretical background to this invention;





FIG. 4

is a schematic elevational view of a first embodiment of the major component which is the focus of this invention.





FIG. 5

is a schematic elevational view of a second embodiment;





FIG. 6

is a view similar to

FIG. 1

, but showing the incorporation of the inventive structure into a component; and





FIG. 7

is a schematic elevational view of a third embodiment.











DETAILED DESCRIPTION OF THE DRAWINGS





FIG. 1

illustrates how a light pipe


5


and a light diffuser


3


are currently used to direct light from two LEDs


6


located on a printed circuit board


8


(PCB) up to the surface


3




a


of a component


4


. The PCB supports various electronic components


7


facing in the opposite direction from the surface of a component


4


. An elastomeric strip


9


allows depression of a key button


2


to be sensed by detection circuitry on the PCB. The light pipe


5


performs the same function as the key buttons, in that both items bring product features out to convenient physical locations.





FIG. 2

shows the prior art light pipe


5


in greater detail. Two LEDs


6


direct light energy up to through light pipe


5


to the diffuser


3


where it can be viewed. In this instance, the light pipe is shown to be of substantial size, since it conveys important information to the user (i.e., message waiting indicator, etc.). The curved parts visible at


5




a


in

FIG. 1

have been “straightened out” in

FIG. 2

, in order to simplify the explanation of its use in an infrared context.




An important aspect of the present invention is the modification of the construction of the light pipe such that, using the concept known as wavelength division multiplexing (WDM), it is possible to use the light pipe for transmission of visible wavelengths and transmission/reception of invisible (infrared) wavelengths. For a better understanding of this concept, attention is directed to FIG.


3


.




Wavelength division multiplexing has its origins in the fiber optic communications field.

FIG. 3

shows two transmitting light sources


10


,


13


, and detectors


11


,


12


operating at spectral wavelengths coupled at


15


into a single fibre optical cable


14


(effectively reducing the number of fibres requires in an installation).




Internal reflections from the transmitter


10


travelling down the cable


14


and subsequently picked up by the receiver


12


are ignored because of the receiver's sensitivity to its optimal wavelength.




The unique aspect of the present invention is that by modifying the light pipe only, a new feature can be incorporated into a product, without requiring changes to the external plastics.




Illustrated in

FIG. 4

is a method of coupling an infrared transceiver into the previously described light pipe. An infrared transceiver module


16


is coupled into the light pipe


18


, which has been moulded to conform to the shape of the lenses of the transceiver. A slot


17


is provided within the light pipe material, in order to separate the infrared transmitter energy and prevent it from being reflected back to the receiver immediately adjacent to it. The top of the light pipe is moulded to provide a lenticular protuberance


19


so that it distributes/collects infrared energy over a wide code angle. For illustrative purposes, the drawings show transmitted energy at two separate spectral wavelengths as arrows at different lengths. The short arrows represent photons emitted by the visible red LEDs (approximately 660 nm) and the longer dashed arrows are photons emitted by the invisible infrared LEDs (approximately 890 nm).




In

FIG. 4

, the light pipe consists of two separate pieces joined together by the upper light diffuser


3


. As an alternative to this approach, the embodiment illustrated in

FIG. 5

incorporates an intermittent slot


20


into the light pipe, so that a single light pipe provides optical separation between the halves. The narrow aperture provided by the slots minimizes energy coupling between the halves, and yet allows the piece to be manufactured as a single unit.

FIG. 5

also shows alignment pins


21


moulded into the light pipe


18


. These pins


21


fit into holes drilled in the PCB


8


, and allow accurate positioning of the light pipe


18


over the optical devices


6


.




It is expected that the increased separation between the infrared transceiver and the front of the product created by using the inventive light pipe


18


will result in greater ESD immunity.





FIG. 6

shows how an infrared transceiver


16


could be incorporated with a specially modified light pipe into the prior art product shown in FIG.


1


.




Further variations of this invention are possible. For example,

FIG. 7

shows the concept of a single piece moulded plastic light pipe


18




a


with a number of slots, potentially simplifying the design of LED arrays within products.




While several embodiments of this invention have been illustrated in the accompanying drawings and described hereinabove, it will be evident to those skilled in the art that changes and modification may be made therein without departing from the essence of this invention, as set forth in the appended claims.



Claims
  • 1. For use with a component defining a surface, the component including a printed circuit board supporting light-generating means, along with light-transporting means for conducting light from the light-generating means to a light diffuser adjacent the surface, the improvement wherein the light-transporting means is in the form of two juxtaposed light pipe portions, and wherein an infrared transceiver module is coupled into both of the light pipe portions adjacent the light-generating means, each light pipe portion transporting visible light to the diffuser and a first one of said light pipe portions transporting invisible infrared light from transceiver, a second one of said light pipe portions transporting invisible infrared light to said transceiver.
  • 2. The improvement claimed in claim 1, in which an elongate, rectilinear slot separates the light pipe portions.
  • 3. The improvement claimed in claim 2, in which the slot has spaced-apart bridges, and in which both light pipe portions are integrally molded together.
  • 4. The improvement claimed in claim 3, in which the light diffuser is shaped to define at least one lenticular protuberance, whereby light is distributed or collected over a wider cone angle that would occur if the diffuser were without such protuberance.
  • 5. The improvement claimed in claim 4, in which alignment pins are molded into the light pipe portions, the pins being adapted to fit into holes provided in the printed circuit board, thus allowing accurate positioning of the light pipe portions with respect to the said light-generating means.
  • 6. The improvement claimed in claim 3, in which alignment pins are molded into the light pipe portions, the pins being adapted to fit into holes provided in the printed circuit board, thus allowing accurate positioning of the light pipe portions with respect to the said light-generating means.
  • 7. The improvement claimed in claim 1, in which the light diffuser is shaped to define at least one lenticular protuberance, whereby light is distributed or collected over a wider cone angle than would occur if the diffuser were without such protuberance.
  • 8. In a component defining a surface and including a printed circuit board supporting light-generating means, and further including light-transporting means for conducting light from the light-generating means to a light diffuser adjacent the surface, an improved method of operation wherein an infrared transceiver module is coupled into both of the light pipe portions adjacent the light-generating means, each light pipe portion transporting visible light to the diffuser and a first one of said light pipe portions transporting visible light to the diffuser and a first one of said light pipe portions transporting invisible infrared light from said transceiver while a second one of said light pipe portions transports invisible infrared light to said transceiver.
  • 9. The method claimed in claim 8, in which an elongate, rectilinear slot separates the light pipe portions.
  • 10. The method claimed in claim 9, in which the slot has spaced-apart bridges, and in which both light pipe portions are integrally molded together.
  • 11. The method claimed in claim 10, in which the light diffuser is shaped to define at least one lenticular protuberance, whereby light is distributed or collected over a wider cone angle than would occur if the diffuser were without such protuberance.
  • 12. The method claimed in claim 11, in which alignment pins are molded into the light pipe portions, the pins fitting into holes provided in the printed circuit board, thus accurately positioning the light pipe portions with respect to the said light-generating means.
  • 13. The method claimed in claim 10, in which alignment pins are molded into the light pipe portions, the pins fitting into holes provided in the printed circuit board, thus accurately positioning the light pipe portions with respect to the said light-generating means.
  • 14. The method claimed in claim 8, in which the light diffuser is shaped to define at least one lenticular protuberance, whereby light is distributed or collected over a wider cone angle than would occur if the diffuser were without such protuberance.
Priority Claims (1)
Number Date Country Kind
0011877 May 2000 GB
Parent Case Info

This application is a continuation of U.S. patent application Ser. No. 09/861,207 filed May 18, 2001 now U.S. Pat. No. 6,641,309 and claims priority of U.K. Patent Application Ser. No. 001877.8 filed May 18, 2000.

US Referenced Citations (8)
Number Name Date Kind
4764984 Franke et al. Aug 1988 A
5347601 Ade et al. Sep 1994 A
5410410 Yamazaki et al. Apr 1995 A
5785404 Wiese Jul 1998 A
5901261 Wach May 1999 A
4876446 Kambe et al. Oct 1999 A
5963349 Norte Oct 1999 A
6327412 Kakui et al. Dec 2001 B1
Continuations (1)
Number Date Country
Parent 09/861207 May 2001 US
Child 10/619306 US