Abstract:
An assembly is provided that allows construction of a watch that includes multifunctional illumination options. The assembly of the present invention provides a means for illuminating the watch face, a high intensity flashlight and a watch locator beacon. The assembly overcomes the drawbacks associated with filament lamps by using LED lamps that provide greater brightness with less power consumption. Further, the present invention relies on a unique feature of LED&#39;s, whereby they are only illuminated by DC power at the right polarity to provide a compact assembly that utilized a minimum amount of space.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is related to and claims priority from earlier filed provisional patent application No. 60/459,343, filed Apr. 1, 2003, and is a continuation in part of U.S. application Ser. No. 10/360,781, filed Jul. 23, 2003, now U.S. Pat. No. 7,023,763, issued Apr. 4, 2006. 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to illumination devices for incorporation into wristwatches. More specifically, this invention relates to a multifunction illumination assembly for incorporation into wristwatches whereby LED lighting elements are provided for use to illuminate the watch face, to act as a watch locator and to serve as a flashlight. 
   In the prior art, various types of illumination devices have been proposed for wristwatches to enable reading the time under poor light conditions. Primarily, the application of phosphorescent materials to watch dials has been employed with varying degrees of success and all suffering from the well-known shortcoming of being difficult to see particularly with the passage of time as the potency of the phosphorescent material decreases. In addition, the phosphorescent material requires periodic recharging through exposure to light in order for the level of phosphorescent output to be maintained. Finally, the luminous materials used in dials of the foregoing watches also lose their light emitting capacity with age and generally provide substantially less than fully satisfactory performance over time as the watch ages. 
   As an alternative to the use of phosphors, electric devices for watch illumination have also been employed with some limited success. Such devices usually take the form of small incandescent bulbs powered by a battery and arranged inside the case of the wristwatch. Typically the placement and arrangement of these batteries and bulbs is assisted by the further implementation of light pipes or reflectors that redirect the light output towards the watch dial thereby enabling the numerals on the dial to be seen. In other assemblies, it has been proposed to provide a small auxiliary battery outside the watchcase in a special attachment connected to the watchband. In this case, an incandescent bulb is provided in the watch crystal, which is connected to the auxiliary battery by lead wires and a switching means. Alternately, the prior art discloses an incandescent bulb installed in the exterior of the watchcase in a housing on the watchband and connected to a battery also disposed within the housing. A deformable or flexible wall allows the circuit to be closed to illuminate the dial by pressing the flexible wall. 
   In all of the foregoing arrangements, the lead wires passing between the power source in the watchband attachment and the incandescent bulb in the case or crystal are subject to possible malfunction, due to breakage caused by the constant and repetitive movement between the case and the attachment. Also, the arrangements described are not easily utilized as a flashlight, wherein the light is directed away from the watch dial, if such functionality is desired by the user. 
   Another shortcoming of many of the prior art devices is that they inefficiently rely upon a relatively powerful illumination source, which attempts to illuminate the entire area of the dial by a flood of visible light output from the source. When illuminated in this manner, the nature of the light output causes portions of the dial nearest the light source to become overly illuminated in order to provide sufficient output so that the portions of the dial that are spaced from the light source receive adequate illumination. Additionally, this approach tends to cause shadows across the watch dial that are especially pronounced when the dial includes curved surfaces or three-dimensional objects thereon. Other drawbacks of the prior known devices for providing dial illumination include the fact that they are bulky and are frequently both delicate and expensive. In general, these devices employing incandescent filament operated bulbs have not been accepted for portable devices due to the fact that they require substantial battery capacity for their operation due to their substantial power requirement. Further, these filament bulbs have a relatively short useful life span as compared to the life of the watch thereby making it necessary to provide for replacement of the bulb in the event that it burns out. 
   BRIEF SUMMARY OF THE INVENTION 
   In accordance with the present invention, an assembly is provided that allows construction of a watch, which includes multifunctional illumination options. The assembly of the present invention provides a multi functional means for illuminating the watch face, directing a high intensity flashlight beam outwardly from the watch and locating the watch via a locator beacon. The assembly overcomes the drawbacks associated with filament lamps by using LED lamps that provide greater brightness with less power consumption. 
   The watch face illumination function utilizes a relatively short wavelength light source to illuminate the face of the watch. The use of a short wavelength emitter has two useful purposes in the context of the present invention. First, short wavelength emitters are more effective in energizing phosphorescent materials, thereby causing a higher output of illumination of the features on the watch face for a smaller expenditure of energy input. Second, an emitter in this range is on the borderline of the visible light spectrum and has a lower impact on the users visual accommodation when the emitter is activated. Specifically, the activation of the emitter has a reduced impact on the user&#39;s “night vision”. 
   The outwardly directed flashlight function utilizes a separate emitter with an output in the visible light range. To facilitate the creation of an easy to operate device, the same actuator that is used to operate the watch face illumination function is also used to activate the flashlight function. A logic chip is placed in the watch that monitors the duration and manner in which the actuator is depressed so that it can selectively activate the desired function. To this end, the present invention may also utilize a unique feature of LED&#39;s, whereby they are only illuminated by DC power at the right polarity to provide a compact assembly that utilized a minimum amount of space. 
   Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings which illustrate the best mode presently contemplated for carrying out the present invention: 
       FIG. 1  is a perspective view of the illuminated watch flashlight of the present invention; 
       FIG. 2  is a cross-sectional view thereof taken along the line  2 — 2  of  FIG. 1 ; 
       FIG. 3  is a bottom view of the illumination assembly for the illuminated watch of the present invention; 
       FIG. 4  is a top view of the illumination assembly for the illuminated watch of the present invention; 
       FIG. 5  is a detail view of the interface between the illumination assembly and the LED support member; and 
       FIG. 6  is a rear view of the LED support member. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings, in general, the present invention is directed to an assembly that is installed into a watch case to provide illumination functionality for the watch. The assembly includes two major components that are installed into a watch case to provide the required functionality by utilizing a dedicated power source while remaining completely segregated from the time keeping functions of the watch. 
   The first component is a small circuit board  2  assembly that has a battery  4 , a movable switch actuator  6  and a logic chip  8  mounted thereon. This circuit board assembly  2  is configured to fit within the back of a watch  20  without interfering with the main time keeping mechanism within the watch case. Further, a second assembly  10  is provided to support LED elements that provide the required illumination functions. 
   The primary assembly, seen best in  FIGS. 3 and 4 , is simply a circuit board  2  with the operative components mounted thereon. The required contact clips  12 ,  14 ,  16 ,  18  to engage the power source  4  as well as the LED support assembly  10  are clearly illustrated, as is the switch  6  in the form of a spring contact. As is best seen in the cross-sectional view of  FIG. 2 , the entire assembly is configured and sized so as to allow it to be mounted into a conventional type watch assembly  20 . While the preferred embodiment of present invention is shown to rely on a separate battery  4  power source, the present invention also anticipates that the assembly could also get the required power by piggybacking power from the main watch  20  power source. 
   The primary assembly is preferably formed as a printed circuit board  2  with all of the required circuitry mounted thereon. To this end, a logic chip  8  may be mounted onto the circuit board  2  to provide the overall assembly with multifunctionality. Further battery contacts  12 ,  14  are provided to retain the battery  4  and supply power to the lighting assembly. Interface clips  18 ,  16  are provided to create electrical connectivity between the primary assembly circuit board  2  and the LED mounting assembly  10 . 
   The LED mounting assembly  10  is configured to be placed in a side mount position in the side of the watch case  22 . The mounting assembly  10  has two LED emitters  24 ,  26  mounted thereon. The first LED emitter  24  is a high brightness LED suitable for use as a flashlight. The LED  24  may be any acceptable color for flashlight use including but not limited to red, white, blue or green. The LED  24  is mounted to the assembly  10  so that the optical element extends through a small opening in the side of the watch case  22  towards the exterior of the watch  20  thereby serving as a flashlight when energized. The second emitter  26  is a flat or surface mount emitter having a small form factor. In the preferred embodiment, the LED  26  is a near ultraviolet emitter, although the LED  26  may be any color emitter suitable for illuminating the watch face  28 . The second emitter  26  is placed onto the mounting assembly  10  opposite the first LED  24  and faces in towards the interior of the watch case  22 . The second emitter  26  is positioned adjacent to an opening in the wall  22  of the watch case  22  just above the face  28  and beneath the crystal  30 . 
   By providing the illumination assembly in two parts, the manufacturability of the watch  20  is enhanced. Since watches generally have a limited amount of available space within the case  22 , it is important to provide an illumination assembly that can be installed into the case  22  without disrupting the rest of the watch  20  mechanism  29 . This problem is further complicated by the fact that to provide a desirable flashlight function, the light output must be directed out the side of the watch  20  in an efficient manner. The present invention allows for a small LED mounting assembly  10  to be placed into the side of the watch case  22  before the watch mechanism  29  is installed. The primary circuit board assembly  2  is then installed into the back of the watch  20  after the watch mechanism is installed. Electrical contact between the primary circuit board  2  and the mounting board  10  is provided via spring clips  16 ,  18 . This assembly allows for enhanced serviceability of the entire watch  20  assembly and provides for a compact and fully contained device. Further the assembly of the present invention provides for easy replacement of the battery  4  used to energize the lighting assembly as it is likely that this battery  4  will be expended at a much higher rate than the primary battery used to power the timekeeping function. 
   In operation, when the emitter  26  is energized, it floods  26  the face  28  of the watch with energy for a short period of time. In the preferred embodiment, the case  22  is flooded with near UV energy at a wavelength of approximately between 405 nm and 435 nm. The near UV energy energizes the phosphors deposited on the watch face  28  and the operational components such as watch hands to cause the watch  20  to illuminate. The phosphor material is selected to be particularly suited for energization by near UV energy to enhance the speed and intensity at which it energizes. While near UV is disclosed, this manner of illumination may work equally well with other LED emitter colors and other matched phosphor colors. In general principal, the phosphor simply must be matched to the output wavelength of the emitter energy used to energize it. In operation, phosphors charge up meaning that a phosphor is charged by an emitter that emits at a shorter wavelength than the output wavelength of the phosphor. Blue emitters charge green and yellow phosphors, yellow emitters charge red phosphors, etc. Therefore, in the preferred embodiment a yellow-green phosphor is utilized on the indicia while a near UV emitter is used to charge the phosphor. 
   The use of a near UV emitter  26  to energize and illuminate the watch dial  28  is also important as it relates to the manner in which the near UV energy impacts the user&#39;s visual system. In particular, the need for illuminating the face  28  of the watch  20  arises when the user wants to view the watch  20  in a low light environment. The user&#39;s vision in this environment is typically adjusted for some level of viewing even though the lighting may not be sufficient for viewing the indicia on the watch face  28 . If the watch  20  included a means for illuminating the face  28  that utilized white light, the burst of white light, even if momentary, would disrupt the user&#39;s “night vision” adjustment. The present invention utilizes an emitter  26  to illuminate the watch face  28  that emits energy at the low end of the visual spectrum. Specifically, by emitting near UV energy, the light output is principally directed to energizing the phosphor on the watch face  28  and providing a low level of visible background illumination of the watch face  28 . In this manner, the illumination function of the present invention has a low impact on the user&#39;s “night.vision” while clearly allowing the user to identify the relevant features on the watch face  28 . 
   Another important feature of the present invention is that the particular property of LED&#39;s that causes them only to illuminate when DC current is applied in one direction allows the multifunctional feature of the watch to be achieved in a compact space. The first  24  and second  26  emitters are mounted onto a small board  10  where the positive and negative leads of each are connected in parallel in opposition to one another. In other words, the negative lead of the first LED  24  is connected to the positive lead of the second LED  26  and the positive lead of the first LED  24  is connected to the negative lead of the second LED  26 . In this manner, when voltage is applied to the LED assembly  10  with one polarity, the first LED  24  will illuminate, hen the polarity is reversed the second LED  26  will illuminate. This allows the LED support assembly  20  to be connected to the circuit board  2  with only two connection leads  16 , 18 . The logic chip  8  on the primary circuit board  2  controls the polarity in response to input from the switch  6 . For example, if the switch  6  is simply pressed and released, the chip  8  may activate the UV emitter  26  to energize the watch face  28 . If the switch  6  is held for more than momentary contact, the chip  8  may activate the high intensity LED  24 . In this manner, any range of operational configurations may be obtained. 
   While the present invention discloses the most efficient manner to provide contact between the primary circuit board  2  and the LED mounting board  10 , other configurations would also be anticipated within the present invention. Clearly, rather than providing two contacts  18 ,  16  and utilizing reverse polarity, three contacts could be provided by sharing a common negative terminal and providing two separate positive terminals. Similarly, four terminals may be provided wherein each LED contact is made discreetly. 
   Finally, the present invention includes a third small LED element  32  that protrudes to the exterior of the watch  20  either in the face  28  of the side of the casing  22 . The third LED  32  will blink at a predetermined interval to act as a locator beacon. 
   Clearly, the present invention is novel in that it exploits the intrinsic operational differences between LED&#39;s and traditional filament type lamps. Previously, where package size, durability and power consumption was an issue, LED&#39;s can be incorporated to allow the enhanced functionality described herein. In particular, the low energy consumption of the LED&#39;s the long lamp life and the small size provides for a durable and compact device that could not be achieved in the prior art. 
   While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.