Abstract:
A projection device is disclosed, wherein the projection device includes a first circuit board, a second circuit board positioned in a spaced-apart relation to the first circuit board, a first connector extending from the first circuit board generally linearly toward the second circuit board, and a second connector extending from the second circuit board generally linearly toward the first circuit board, wherein the first connector and the second connector are coupled together to form an electrically conductive pathway between the first circuit board and the second circuit board.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present application claims priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application Ser. No. 60/475,568, which was filed on Jun. 2, 2003. The disclosure of that application is hereby incorporated by reference in its entirety for all purposes. 
     
    
     
       TECHNICAL FIELD  
         [0002]    The present invention relates generally to the electrical connection of one circuit board to another circuit board in a projection device. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0003]    The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which the like references indicate similar elements and in which:  
         [0004]    [0004]FIG. 1 is a schematic illustration of an embodiment of a projection device.  
         [0005]    [0005]FIG. 2 is an isometric view of an assembly of electrical and optical components of an embodiment of a projection device, showing an embodiment of a board-to-board connector for connecting spaced-apart first and second circuit boards.  
         [0006]    [0006]FIG. 3 is a magnified isometric view of a first connector of the embodiment of FIG. 2.  
         [0007]    [0007]FIG. 4 is a magnified isometric view of a second connector of the embodiment of FIG. 2  
         [0008]    [0008]FIG. 5 is a magnified isometric view of the first connector of the embodiment of FIG. 2, showing a schematic outline of an alternate shroud configuration. 
     
    
     DETAILED DESCRIPTION  
       [0009]    A projection device or image-generating device  10  is illustrated schematically in FIG. 1. The projection device  10  may be adapted to project an image on a display surface, including, but not limited to, a screen, a wall, or other viewing surface or area. As used herein, a projection device or image-generating device may include any suitable display device or image projector, including, but not limited to, a digital projector, a liquid crystal display (LCD) projector, a digital light processing projector, etc.  
         [0010]    In its most basic form, the projection device  10  includes a light source (or lamp)  12  and an optical engine (or image engine)  14  contained within an enclosure, such as a casing  13 . The light source  12  may be adapted to produce a beam of light and project the light towards the optical engine  14 , which may be configured to generate an image. The light source  12  typically includes a lamp (not shown) positioned within a reflector (not shown) that is configured to direct most of the emitted light along the optical path of the projection device  10 . The light source  12  may include any suitable type of lamp. Examples include, but are not limited to, metal halide lamps and ultra-high-pressure (UHP) arc lamps, etc. The emitted light may also pass through one or more filters (not shown), such as an infrared (IR) or ultraviolet (UV) filter, to filter out unwanted parts of the emission spectra of the lamp.  
         [0011]    Light produced from the light source  12  may be channeled through an interface tube or spacer  16  to optical engine  14 . The optical engine  14  may include filters, color wheels, lenses, mirrors, integrators, condensers, and other optical elements (not shown).  
         [0012]    The optical engine  14  may include an image-producing element  18 . Any suitable image-producing element may be used. Examples include, but are not limited to, digital micromirror devices (DMD) and LCD panels. The image-producing element  18  may be configured to project light toward one or more mirrors, lenses and/or other optics, such as a projection lens  22 , which, in turn, may be configured to reflect light toward a display surface.  
         [0013]    The projection device  10  typically includes one or more power sources  20 . The power source  20  is typically at least partially disposed on a power source circuit board, and may be linked to the light source  12 , the image-producing element  18 , and other components, such as a control circuit board within the projection device to provide power to these components.  
         [0014]    Operation of light source  12  and other electronic components in projection device  10  may increase the temperature of the projection device  10  during use. If the temperature of the projection device  10  exceeds critical limits, portions of the device may malfunction and/or have a shorter life span. Maintaining temperatures within the device at operating levels thus may prevent the device from malfunctioning and/or increase the lifespan of components and parts. A blower system  24  may thus be provided to circulate ambient air through the projection device and eject circulated air, as depicted by lines  26 , thus helping to cool projection device components. The blower system  24  may include a blower portion, such as a fan, wheel, or similar air mover, powered by a blower motor.  
         [0015]    [0015]FIG. 2 further illustrates various components within an exemplary projection device. As illustrated, the projection device includes a power circuit board  30  and a control circuit board  32 . The power board  30  typically is an electronic circuit board configured to regulate DC power within the projection device. The control board  32  includes electrical components configured to control the operation of the projection device  10 , such as various logic components. The depicted power board  30  is configured to be positioned adjacent a first side of casing  13 , and the depicted control board  32  is configured to be positioned adjacent a second, opposing side of casing  13  in projection device  10 , such that the space between the power board  30  and the control board  32  may accommodate electrical and/or optical components, and/or may admit the passage of a flow of cooling air.  
         [0016]    The power board  30  is electrically connected to the control board  32  to supply power to the control board  32  via a board-to-board connector  36 . In many prior devices, the electrical connections between two spaced-apart circuit boards are achieved through the use of connection devices such as wire harnesses, spanning circuit boards and floating connectors. However, the wire harnesses, spanning circuit boards and floating connectors may be bulky, and thus difficult to physically accommodate within a small-sized projection device. Furthermore, such bulky connection devices may disrupt the airflow through the projection device.  
         [0017]    Further, in small devices, the distance between power board  30  and control board  32  may be less than the minimum manufacturable length for wire harnesses, even where the boards are separated as far apart as practical in the device. Manufacturing limitations may cause the wire harness to be bulkier than necessary. Such bulky harnesses may interrupt airflow and disrupt other components within the device. Similarly, stray wires within the wire bundle may disrupt various operating components, such as the color wheel, within the projection device.  
         [0018]    Additionally, such connection devices may be difficult to assemble within the confined space of the projection device. For example, the space around the location of the connection may be difficult to access or view during assembly. This may make it difficult to solder or otherwise connect the wires to each of the boards during assembly. Moreover, a partially-blind assembly process may make it difficult to adequately couple the wiring harness to each other, and/or to desired locations on the boards.  
         [0019]    Furthermore, the location of the two circuit boards within a projection device may be variable relative to each other due to manufacturing tolerances, thus potentially frustrating the use of precision mating connectors that are often used in spanning circuit boards. Moreover, it may be difficult due to the size of the projection device to allocate space to floating connectors having retention screws that may need to be tightened once the connection between the two boards is made.  
         [0020]    In contrast to wire harnesses, spanning circuit boards and floating harnesses, board-to-board connector  34 , board-to-board connector  34  may be adapted to minimize disruption of other components with the device and airflow within the device, while providing a precise connection of two electronic circuit boards. Further, the board-to-board connector may accommodate variations in the position of the electronic circuit boards relative to each other to accommodate manufacturing tolerances, shocks to the system such as being dropped onto a hard floor, etc.  
         [0021]    Referring again to FIG. 2, board-to-board connector  34  may include a first connector  36  and a second connector  38 . The first connector  36  may be coupled to the power board  30 , as shown in more detail in FIG. 3, and the second connector  38  may be coupled to the control board, as shown in more detail in FIG. 4.  
         [0022]    The first connector  36  includes a first plurality of leads  40 , and the second connector  38  includes a second plurality of leads  42 . The first plurality of leads  40  terminate at a first connecting structure  44 , and the second plurality of leads  42  terminate in a complementary second connecting structure  46  configured to connect to the first connecting structure  44 . Any suitable type of connecting structure may be used for the first connecting structure  44  and the second connecting structure  46 . Examples include, but are not limited to, male/female connecting structures.  
         [0023]    The plurality of leads  40  of the depicted first connector  36  extend away from the power board  30  in a generally linear manner, and in a direction generally orthogonal to an interior face  47  of the power board  30 . Likewise, the plurality of leads  42  of the depicted second connector  38  extends away from the control board  32  in a generally linear manner, and in a direction generally orthogonal to an interior face  48  of the control board  32 . In this configuration, the first connecting structure  44  and second connecting structure  46  easily connect to each other where power board  30  and control board  32  are arranged in a generally coplanar relationship. However, it will be appreciated that the first connector  36  and the second connector  38  may extend from the power board  30  and the control board  32 , respectively, at any other suitable angles, depending upon the relative orientations and positions of the power board  30  and control board  32  within projection device  10 .  
         [0024]    The linear configuration of the leads  40  and  42  of first connector  36  and second connector  38 , respectively, may occupy less space in the interior of projection device  10  than connectors such as wire harnesses, which typically includes at least some bends. Thus, the use of connector  34  may impede the flow of cooling air through the projection device  10  to a lesser extent than wire harnesses and similar connectors.  
         [0025]    The first plurality of leads  40  and second plurality of leads  42  each have sufficient length for the combined length of the plurality of leads  40  and the plurality of leads  42  to bridge the space between the power board  30  and the control board  32  when first connecting structure  44  is coupled with second connecting structure  46 . The first and second pluralities of leads  40 ,  42  may be made of a material rigid enough to support the first and second connecting structures  44 ,  46  in generally fixed positions when the connecting structures are detached, yet flexible enough to allow the first and second pluralities of leads  40 ,  42  to absorb variations in positions due to thermal expansion/contraction, manufacturing tolerances, etc. It should be noted that although each connector set in the illustrated embodiments include ten leads, either more or fewer leads may be used.  
         [0026]    The first and second pluralities of leads  40 ,  42  may be further supported through an alignment shroud. The alignment shroud may guide the connection of the power board to the control board, and also may provide additional insulation and protection to first and second connectors  36 ,  38 . The alignment shroud may include a first shroud segment, shown at  50  in FIG. 3, that partially or fully encloses first connector  36 , and a second shroud segment, shown at  52  in FIG. 4, that partially or fully encloses second connector  38 . The first and second shroud segments  50 ,  52  may be configured to attach together, for example, via a snap connection, when first connector  36  and second connector  38  are coupled together. Such alignment shrouds may help to ensure precise alignment of the first connecting structure  44  with the second connecting structure  46  during assembly of projection device  10 . Such alignment shrouds may further allow for positive engagement the first and second connecting structures  44 ,  46  regardless of the ease/difficulty of viewing the connection of the connecting structures  44 ,  46  during assembly.  
         [0027]    In some embodiments, the use of board-to-board connector  34  to join two spaced-apart circuit boards enables the first connector  36  and second connector  38  to be easily connected even where the connection process is a blind or semi-blind process. For example, after placing the power board  30  in a desired location and after installing any other desired projector components, the control board  32  may be positioned over the power board  30  such that the second connecting structure  46  is positioned directly opposite the first connecting structure  44 . Then, second and first connecting structure  46  and  44  may be joined simply by pushing the control board  32  toward the power board  30 . Therefore, first connector  36  may be coupled to second connector  38  in a fast and efficient manner, even where the connectors are located in areas that are partially or totally obscured by other components, or difficult to access. Furthermore, as mentioned above, the first and second pluralities of leads  40 ,  42  may be configured to have sufficient flexibility to accommodate positional variation of circuit boards of different devices during the assembly process. For example, once the alignment shrouds are interlocked, the leads may adapt and bend in accordance with the positions of the connected boards.  
         [0028]    [0028]FIG. 5 shows an alternate shroud configuration, generally at  150 . Instead of having two separate shroud portions, such as the shroud shown in FIGS. 3-4, shroud  150  has a single-piece construction configured to hold both first connector  36  and second connector  38  within its interior. Shroud  150  may help to aid the alignment of the first connector  36  with the second connector  38  during projector device assembly. For example, the second connector  38  may be simply inserted into shroud  150  as the second connector  38  is lowered toward the first connector  36 . Shroud  150  then may function to guide the second connector  38  into correct alignment with the first connector  36 , even in situations in which the second connector  38  and first connector  36  are in blind locations within projection device  10 .  
         [0029]    The depicted connector  34  may occupy a minimum footprint within the projection device compared to other connectors. The compactness of connector  34  enables reduction of the overall size of the projection device  10  to sizes that may be difficult to achieve using ribbons or wire harnesses, spanning circuit boards and/or floating connectors. Furthermore, the use of connector  34  may allow separate circuit boards to be placed at spaced-apart locations in a device to make room for other components between the boards. For example, in the depicted embodiment, the separation of power board  30  and control board  32  allows various optical and/or electrical components, such as projection lens  22 , to be located between the boards. Additionally, the configuration of the board-to-board connector may offer less of an impediment to a flow of cooling air through the projection device than the other types of connectors discussed above.  
         [0030]    Although the present exemplary embodiments illustrate the use of a board-to board connector in a projection device, it should be appreciated that the board-to-board connector described herein may be used in any suitable device requiring compact and precise alignment of two circuit boards. Furthermore, although the present disclosure includes specific embodiments, specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.