Patent Document

CLAIM OF PRIORITY 
     This application is a continuation of, and claims priority from, application Ser. No. 12/074,370, filed on Mar. 3, 2008, now U.S. Pat. No. 7,690,806 titled: ILLUMINATING HEADLAMP PROVIDING SUBSTANTIALLY UNIFORM ILLUMINATION, and claims the benefit of the earlier filing date, pursuant to 35 USC §119(e), to that patent application entitled “Illuminating Headlamp and Method of Illumination,” filed in the US Patent and Trademark Office, on Mar. 30, 2007, and afforded Ser. No. 60/921,150 and pursuant to 35 USC §120 to that patent application entitled “Illumination Assembly,” filed on Oct. 18, 2007 and afforded Ser. No. 11/975,194, the contents of each of which are hereby incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     Illumination devices are employed in a wide variety of contexts. Various types of fine work require high intensity illumination over a small area at a relatively short distance from the eyes of a user. Examples of such fine work include surgery, dentistry and watch and jewelry repair. Illuminating headsets are suited for these types of work as they allow a light to be projected at an area while leaving the hands free to manipulate tools or surgical equipment. 
     Prior art headsets typically have a remote source of illumination connected by a fiber optic cable to the headset. The remote source of illumination is typically a bulb, which may be, for example, a metal halide or a xenon bulb. A suitable lens is provided to couple the bulb output to a fiber optic cable, in the headset. While the fiber optical cable attached to the headset is cumbersome and may be inconvenient to the user, the power requirements and heat output of metal halide and xenon bulbs make it impractical for these illumination sources to be mounted on the headset. 
     In the prior art, the use of light-emitting diodes as a light source has been suggested. U.S. Pat. No. 6,955,444, to Gupta, discloses the use of a headlamp with two LEDs. Each LED is mounted relative to a reflector to provide sufficient illumination on a target region. However, reflectors typically provide a diffuse illuminated region. The use of two LEDs also adds weight, cost and complexity to the device. 
     US Published Patent Application serial no. 2005/0099824, to Dowling, also discloses the general concept of integrating an LED into a headlamp. However, this patent application provides little detail as to implementation. Another example in the prior art is the Zeon® LED Portable High-Definition Light, available from Orascoptic, 3225 Deming Way, Suite 190, Middleton, Wis. 53562. This device incorporates a LED mounted in front of reflectors. A collimator captures the light from the LED. The use of the collimator captures a maximum percentage of the light emitted by the LED. However, illumination is not uniform over the target area. Rather the intensity of illumination peaks at the center and then gradually decreases with distance from the center of the illuminated area. 
     However, this decrease in the illumination from the center of the target area is disconcerting as it limits the illuminated field of view. Hence, there is a need in the industry for an illuminated headset that provides a target area or zone of substantially uniform illumination. 
     SUMMARY THE INVENTION 
     An illuminating headlamp consisting of a headband and at least one optical device providing illumination at a known distance from said optical device attached to said headband. Each optical device consists of a housing having an open first end and an open second end. There is a light emitting device attached to a mounting which is attached to the second end causing said light emitting device to be orientated at a known angle to an axis of said housing. At least one optically transparent lens is incorporated into said first end, and a means for adjusting said optically transparent lens in order to cause a focal point of the lens to be positioned behind said light emitting device, wherein a zone of substantially uniform illumination is projected at said known distance. 
    
    
     
       BRIEF DESCRIPTIONS OF THE FIGURES 
       The advantages, nature, and various additional features of the invention will appear more fully upon consideration of the illustrative embodiments now to of the described in detail in connection with accompanying drawings where like reference numeral to identify like element throughout the drawings: 
         FIG. 1  represents a perspective view of an illuminating headset. 
         FIG. 2A  represents an isometric drawing of an exemplary LED holding device in accordance with the principles of the invention; 
         FIG. 2B  represents an exploded view of the device shown in  FIG. 2A ; 
         FIGS. 3A-3C  represent simplified exemplary ray diagrams associated with the device shown in  FIG. 1 ; 
         FIG. 4  represents a top view of a LED shown in an array shape suitable for use in the device shown in  FIG. 1 ; 
         FIG. 5  represents a process flow diagram of a method of operation of the device shown in  FIG. 1 ; 
         FIGS. 6A and 6B  represent exemplary illuminated areas associated with focus-ed and defocus-ed operation of the device shown in  FIG. 1 ; 
         FIGS. 7A and 7B  represent exemplary orientation of emitter arrays relative to a single optical device and an assembly as shown in  FIG. 1 ; 
         FIG. 8  illustrates an exemplary emitter mount of use in the assembly shown in  FIG. 2  in accordance with the principles of invention; 
         FIGS. 9A-9C  illustrate views of the relationship of the light-emitting array in the mounting shown in  FIG. 8 ; and 
         FIGS. 10A-10D  illustrate views of an alternate emitter for use in the assembly shown in  FIG. 2  in accordance with the principles of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     It is to be understood that the figures and descriptions of the present invention described herein have been simplified to illustrate the elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity many other elements found in illuminating headsets. However, because these elements are well-known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such element is not provided herein. The disclosure herein is directed to also variations and modifications known to those skilled in the art. 
       FIG. 1  represents an illuminating headset assembly. Headband assembly  10  includes generally two light emitting units, or illumination devices,  100 ,  200  within housing  300 . Illumination devices  100 ,  200  are supported relative to one another with housing  300 , which is attached to assembly  10  by bar  400 . Illumination devices  100 ,  200  are adapted to emit light in relatively narrow beams that intersect and entirely or substantially overlap at a selected distance from the illumination devices. Headband  500  supports housing  300  including illumination devices  100 ,  200 . 
     Although headband assembly  10  is shown to include two light-emitting devices, it would be appreciated that assembly  10  may also be constructed to include only a single light-emitting device. As the principles of operation of the light-emitting devices  100 ,  200  are generally identical; a description of only one of the devices will be described in detail herein. 
       FIG. 2A  represents a single one of the light-emitting devices  100 ,  200  of an illuminated headset in accordance with the principles of the invention.  FIG. 2B  represents an exploded view of the device  100  (or  200 ) shown in  FIG. 2A . 
     Referring to  FIG. 2A , device  100  is an illuminating device having an opaque housing  105  having a distal end  106  and a proximal end  107 , an opening  110  at the distal end  106  and a tapering portion  112  intermediate the distal end  106  and the proximal end  107 . Referring to  FIG. 2B , a light emitting diode  120  is mounted within a mounting  150  that is positioned in housing  105  near the proximal end  107 . The light emitting diode is positioned to emit light toward opening  110 . Lenses  131 ,  132  are positioned in housing  105  distally from the light emitting diode  120  to receive and retransmit through opening  110  a portion of the emitted light. Lenses  131 ,  132  allow the focusing or defocusing of light emitted from light emitting diode  120 . Lenses  131 ,  132  may be adjusted to provide a zone of substantially uniform illumination at a known distance from the distal end of device  100 . 
     Referring to  FIG. 2B , lenses  131 ,  132  may be held in place by sleeve  133 , o-ring  134  and closing-ring  135 . Lenses  131 ,  132  may be spherical or aspherical and may be of a glass composition with or without a plastic coating. Epoxy may be employed to fix lenses  131 ,  132  to sleeve  133 . Although only two lenses are illustrated, it would be recognized that the number and selection of lenses may be varied without altering the scope of the invention. 
     Mounting bracket  140  is attached to housing  105  near the proximal end of assembly  100 . Mounting bracket  140  is an example of a bracket adapted to be attached to a headband  500  ( FIG. 1 ) so that device  100  may be mounted on the head of a user. Mounting bracket  140  is shown having a body with an opening therethrough to receive the proximal end  107  of housing  105 . 
     Mounting pin  142  may be inserted into bore  146  and into corresponding bores in housing  110  and a bore  144  in LED mount  150  (see  FIG. 8 ) to secure housing  105 , mounting bracket  140  and LED mount  150  relative to one another. 
     LED mount  150  may be in physical contact with housing  105  or otherwise configured to provide good heat conduction from mount  150  to housing  105 . LED mount  150  may be selected from a material that is a good heat conductor. For example, mount  150  may be a copper or a tellurium copper alloy. Housing  105  may be made of a similarly good heat conductor, e.g., copper or aluminum. In one aspect, an uneven outer surface of housing  105  may be provided, as illustrated. Such uneven surface may be represented as grooves defined in the outer surface of housing  105 . The uneven surface increases the surface area and, hence, the spread the heat over a greater surface area. In any event, the surface can also be smooth. 
     Although device  100  shown in  FIGS. 2A and 2B  is shown having a conical shape, it would be recognized by those skilled in the art that this illustrates a preferred embodiment of the invention and that other shapes, e.g., cylindrical, are currently contemplated and considered to be within the scope of the invention. 
       FIGS. 3A-3C  represent simplified exemplary ray diagrams associated with the device shown in  FIGS. 2A and 2B . It will be appreciated that lenses associated with lens  130  are merely schematic and may include a plurality of lenses and/or reflectors. Emitter  120  represents a plurality of light emitting diodes arranged in an array  605 . Array  605  may have a pattern as shown in, and described in further detail with regard to a discussion of,  FIG. 4 . 
     Referring to  FIG. 3A , lens  130  is positioned relative to array  605  with its focal point on array  605  so as to project a focused image of array  605  on an incident or target area  330 . Because of the placement of array  605  at the focal point of lens  130 , details of the array may be seen in within the target image. This focused image is undesirable as it fails to provide a substantially uniform illumination within the target area. 
     Referring to  FIG. 3B , lens  130  is configured so that its focal point, identified as  332  is behind array  605 . In this case, the defocusing of the light generated by array  605  causes a defocused image  331  to be projected on a target area at the same distance as shown in  FIG. 3A . The defocused image provides a distinct zone of substantially uniform illumination without displaying the pattern of array  605 . The illuminated area of image  331  is larger than the focused image  330  shown in  FIG. 3A  and has a higher intensity of illumination. Image  331  has a generally rectangular form, as array  605  is generally rectangular, in this illustrated example. Examples of a focused image of an array and a defocused image of an array projected on a target area are shown in  FIGS. 6A and 6B , respectively. 
       FIG. 3C  illustrates a configuration wherein the focal point  332  of lens  130  is positioned in front of array  605 . This arrangement provides a blurred image of the array with indistinct edges and great variation in intensity. The image provides less uniformity and lower intensity than the defocused image shown in  FIG. 3B . 
     As shown in  FIGS. 3A-3C  and  FIGS. 6A and 6B , a defocused image has a larger area, a more even illumination and a higher intensity of illumination when compared to a focused image of emitter array  605 . It will be appreciated that superposition of defocused images of multiple arrays results in both higher illumination intensity and better uniformity of illumination across the illuminated area. In an exemplary embodiment shown, an intensity of about 7,000 foot-candles may be obtained across a field. Devices for providing such intensity are manufactured by Cree with headquarters located in Durham, N.C. The device is sold as the Cree P3 LED: P/N XREWHTL1-0000-07-01 which provides intensity of 7,000 fc at 13″ working distance. The intensity is measured with a Gossen Panlux Light Meter. P/N 3B14095 (Gossen is located in Germany). 
       FIG. 4  represents an exemplary LED emitter assembly  600  incorporated into the optical device shown in  FIG. 2A . Individual LEDs maybe a Cree XLamp High-Power LED, available from Arrow Electronics, Manalapan, N.J. Array  605  is a two-dimensional array having an overall generally rectangular shape. The array  605  may be on a single die or on more than one die. Generally rectangular sub-arrays  610 ,  612 ,  614  and elongated sub-array  616 ,  618  emit light. These sub-arrays may include individual diode elements that are relatively closely spaced together. For example, the diodes may be spaces at 400 dots per inch (dpi) or 1200 dpi. Relatively narrow areas  620 , which may contain controllers and other devices, for example do not emit light. 
     As discussed with regard to  FIG. 3A , a focused projection of array  605  will result in an image with projections of sub-arrays  610 ,  612 ,  614 ,  616  and  618  being bright with dark lines corresponding to areas  620 . Furthermore, variations in light output intensity within sub-array areas may occur. Such variation may occur as a result of errors in manufacturing of the LED sub-arrays. As a result of the pattern of variations in intensity, when a focused image of array  605  is projected onto an incident or target area, noticeable variations in illumination intensity occur (see  FIG. 6A ). 
     However, when a defocused image, as discussed with regard to  FIG. 3B , is projected onto a target area, variations in illumination intensity are reduced so as to create a zone of substantially uniform illumination as seen in  FIG. 6B . 
       FIG. 5  illustrates a method for providing a zone of substantially uniform illumination utilizing the optical devices as shown in  FIG. 2A  when incorporated into the illuminated headset shown in  FIG. 1 . In this exemplary process, an incident plane, such as an opaque sheet, is placed at a desired distance from the illuminated headset  10 . The illumination device  100  ( 200 ) is activated and an image projected onto the incident place is paced into focus. The projected image of the emitting array may appear to include at least one distinct illuminated area and may have relatively sharp edges. (block  705 ). The lens or lenses ( 130 ,  132 ) are then adjusted until a defocused image is obtained, as indicated by block  710  and fixed at block  715 . Lens adjustment may include changing the distance between the lens  130  ( FIG. 2A ) and the array  605 , changing the distance between lenses  131  and  132 , substituting different lenses or adding or removing lenses. As shown n  FIG. 3B , the adjustment causes the focal point of the lenses to be behind the array  605  (defocused). 
     In one aspect, a light meter may be positioned at the desired distance and the lenses may be adjusted until the illumination intensity detected by the light meter is substantially at a maximum. With each lens adjustment, the area of illumination at the selected distance may also be checked to determine when the area is a minimum desired size. It will also be appreciated that different LEDs may be selected. 
       FIG. 6A  illustrates the projection  900  of a focused image of array  605  onto a target area at a desired distance from optical device  100 . As discussed previously, narrow, non-light emitting regions  910  of array  605  are discernable from the illuminated area  905 . In addition, the edges of the illuminated area are less intense than that of the center region. 
       FIG. 6B  illustrates the projection  920  of a defocused image of array  605  onto a target area at a desired distance from optical device  100 . As discussed previously, the illumination across the target area is substantially uniform as denoted by the intensity at the center point  922  and edge point  924 . 
       FIG. 7A  illustrates a front view of the exemplary optical device  100  shown in  FIG. 2A . In this exemplary illustration, the orientation of emitter array  605  is preferably selected be to at an angle of substantially 45 degrees to a transverse axis (not shown) of the devices. The angle of 45 degrees is selected to illuminate an area at a selected distance from the assembly to project an image that is substantially square. Otherwise, the projected illumination may have a wider range in one direction (e.g., horizontal) as opposed to another direction (e.g., vertical). If the angle is changed, then other geometric configurations can be accommodated. For example, at an angle of 90 degrees, the configuration would be a square. 
       FIG. 7B  illustrates a front view of the incorporation of the optical device shown in  FIG. 2A  in an assembly  300  shown in  FIG. 1 . In this embodiment, the optical devices  100 ,  200  are oriented along a horizontal axis of assembly  300 . In this illustrated embodiment, the diode arrays  605 ,  606  are shown having the same orientation to the horizontal axis of assembly  300 . The preferred orientation of the array  605  with regard to an axis of assembly  300  is selected for the reasons similar to that discussed above. Although, the arrays  605 ,  606  are shown in the same orientation, it would be understand that the orientation of the arrays  605 ,  606  may be independently selected and that other orientations, as well as other emitter array shapes, within the optical device have been contemplated and considered to be within the scope of the invention. 
       FIG. 8  illustrates an exemplary mount  150  in accordance with the principles of the invention. Mount  150  is preferable selected from materials that act as a good heat conductor, e.g., copper or tellurium copper alloy. Mount  150  is generally a cylindrical hollow body, closed at one end by wall  1108 , which provides a platform for emitter array  605 , and open at the other end. Major cylindrical wall  123  has a bore  144  through a central axis and a corresponding opposite bore (not shown) along an axis through the central axis of end cylindrical wall  124 . End cylindrical wall  124  is coaxial with, and of lesser diameter than major cylindrical wall  123  and the two walls are joined by a shoulder. End wall  1108  has upstanding members  1105 ,  1106  at opposite sides, positioned to retain a LED array  605  at a selected orientation relative to bore  144 . End wall  1108  lies in a plane substantially parallel to the axis of bore  144 . Bore  125  provides for wiring that allows connection of array  605  (not shown) to a power source. 
     Upstanding members  1105 ,  1106  on surface  1108  are positioned to provide a selected orientation of a LED array (not shown) having a rectangular base and a generally rectangular shape, so that the sides of the LED array are parallel to the sides of the base and that the sides of the array are at an angle substantially 45 degrees relative to the central axis of bore  144  and the bore opposite thereto through major wall  123 . As a result of the orientation of pins  321 ,  322  ( FIG. 9A ) in bore  144  (and corresponding not shown opposite bore hole) of emitter mount  150 , the angle between the axis of bore  144  (and corresponding not shown opposite bore hole) and the sides of array  605  (not shown) when mounted on emitter mount  150 , is fixed at a substantially 45 degree angle relative to a horizontal axis. 
       FIGS. 9A-9C  illustrate views of the attachment of mount  150  within the optical device  100  shown in  FIG. 2A  and an exemplary orientation of the array  605  with regard to the vertical axis of optical device  100 . Pins  321 ,  322  provide means for attaching mount  150  to device  100  and setting the orientation of array  605 .  FIG. 9A  illustrates the insertion of mounting  150  in a distal end of the device  100  and is attachment by pins  321 ,  322 .  FIG. 9B  illustrates a front view of the positioning of array  605  on surface  1108  ( FIG. 8 ) at a preferred angle of substantially 45 degrees to the axis of pins  321 ,  322 .  FIG. 9C  illustrates a front view of a blueprint representation of the positioning of array  605  on surface  1108 .  FIG. 9C  further illustrates a preferred tolerance for the orientation angle of array  605 . 
       FIGS. 10A-10D  illustrate an alternative emitter mounting  1222 . Emitter mount  1222 , similar to mount  150  ( FIG. 8 ) is a good heat conductor. In this alterative embodiment, emitter mount  1222  is generally in the form of a hollow body, open at one end and closed at the other. Emitter mount  1222  has a major cylindrical wall  1223  at its open end and a bore hole  1244  through outer wall  1223 . Bore  1244  may be adapted to receive pins  321 ,  322  ( FIG. 9A ). Emitter mount  1222  has a generally rectangular hollow body  1232  defining the closed end of emitter mount  1222 . Hollow body  1232  is narrower than major cylindrical wall  1223  and the two are joined by a shoulder  1234 . Hollow body  1232  is centered on the axis of major cylindrical wall  1223 . A bore hole  1238  through rectangular hollow body  1232  accommodates wiring to an emitter array (not shown) positioned on surface  1236 . End wall  1236  is so oriented as to accommodate an emitter at a specified orientation relative to bore hole  1244 . In the illustrated example, as may be particularly shown in  FIG. 10D , the sides of end wall  1236  are at angle of substantially 45 degrees relative to bore  1244 . Similarly, bore  1238  in rectangular body  1236  is at an angle, which in the illustrated embodiment is oriented substantially 45 degrees from bore  1244  in main cylindrical wall  1223 . 
     While there has been shown, described, and pointed out fundamental novel features of the present invention as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the apparatus described, in the form and details of the devices disclosed, and in their operation, may be made by those skilled in the art without departing from the spirit of the present invention. 
     It is expressly intended that all combinations of those elements that perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated.

Technology Category: 2