Abstract:
A projection display device includes a screen for having projected images displayed thereon, a main frame overlaying the top edge and the bottom edge of the screen, a pair of side frames adjustably secured to opposite two sides of the main frame to change transverse distances between the side frames, each of the side frames holding one of the side edges of the screen, and a pair of securing members selectively securing the side frames to the main frame at different positions so as to adjust a viewable size of the screen to present different aspect ratios. An electronic apparatus utilizing the projection display device is also disclosed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention generally relates to display devices, and in particular to a projection type display device and an electronic apparatus using the projection display device.  
         [0003]     2. Description of Related Art  
         [0004]     Various kinds of display devices in existence can be sorted into two types, flat panel type display and non-flat panel type display. A cathode-ray tube (CRT) display is a typical non-flat panel display, and trends indicate it will become obsolete due to its relatively large volume. A liquid crystal display (LCD) is a typical flat panel display.  
         [0005]     A liquid crystal display screen is a thin, flat display made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is prized by engineers because it uses very small amounts of electric power, and is therefore suitable for use in battery-powered electronic apparatuses. Each pixel consists of a layer of liquid crystal molecules suspended between two transparent electrodes, and two polarizing filters, the axes of polarity of which are perpendicular to each other. The LCD screen is popular due to its compact volume and low power-consumption.  
         [0006]     However, the LCD screen is complex in structure, and expensive in cost.  
         [0007]     What is needed is a display screen with compact volume and low cost.  
       SUMMARY OF THE INVENTION  
       [0008]     A projection display device includes a screen for having projected images displayed thereon, a main frame overlaying the top edge and the bottom edge of the screen, a pair of side frames adjustably secured to two opposite sides of the main frame to change transverse distances between the side frames, each of the side frames holding one of the side edges of the screen, and a pair of securing members selectively securing the side frames to the main frame at different positions thereby adjusting a viewable size of the screen to present different aspect ratios.  
         [0009]     An electronic apparatus includes a base and a display device pivotably attached to the base. The display device includes an outer casing and a screen received in the outer casing. The screen defines a transverse direction and a longitudinal direction. The outer casing includes a main frame overlaying a back of the screen, and a side frame attaching a side of the screen thereto and reeling in the screen along the transverse direction, the side frame selectively secured to the main frame at at least two different positions along the transverse direction so as to adjust a transverse length of viewable screen to present different aspect ratios.  
         [0010]     Other systems, methods, features, and advantages of the present projection display device and the present electronic apparatus will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present apparatus, and be protected by the accompanying claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     Many aspects of the present projection display device and the present electronic apparatus can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present device. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.  
         [0012]      FIG. 1  is an exploded, isometric view of an outer casing for a display device in accordance with an exemplary embodiment, the outer casing including a main frame and two side frames, and two securing members, and each of the side frame including an engaging member, a reel  40 , and a side margin  50 ;  
         [0013]      FIG. 2  is an enlarged view of a circled portion  11  of the main frame in  FIG. 1 ;  
         [0014]      FIG. 3  is an enlarged view of the engaging member in  FIG. 1 ;  
         [0015]      FIG. 4  is an enlarged view of the securing member in  FIG. 4 ;  
         [0016]      FIG. 5  is similar to  FIG. 5 , but viewed from another aspect;  
         [0017]      FIG. 6  is an assembled, isometric view of the outer casing;  
         [0018]      FIG. 7  is an enlarged view of a circled portion VII in  FIG. 6 ;  
         [0019]      FIG. 8  is an isometric view of a notebook computer in a first aspect ratio according to an exemplary embodiment; and  
         [0020]      FIG. 9  is an isometric view of the notebook computer in a second aspect ratio. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     Reference will now be made to the drawings to describe the embodiments of the present projection display device and the present electronic apparatus, in detail.  
         [0022]     The aspect ratio of an image is a ratio of its display width to its height (usually expressed as “x:y”). For instance, the aspect ratio of a traditional television screen is 4:3, or 1.33:1. High definition television uses an aspect ratio of 16:9, or about 1.78:1. Aspect ratios of 2.39:1 or 1.85:1 are frequently used in cinematography, while the aspect ratio of a sync-sound 35 mm film frame is 1.37:1 (also known as “Academy Aperture” ratio). Silent films, which used the full frame, were shot in 1.33:1.  
         [0023]     The 4:3 ratio for standard television has been in use since television&#39;s origins and many computer monitors use the same aspect ratio. 4:3 is the aspect ratio defined by the Academy of Motion Picture Arts and Sciences as a standard after the advent of optical sound-on-film. Matching this aspect ratio meant that films previously photographed on film could be satisfactorily viewed on TV in the early days of the medium. When cinema attendance dropped, Hollywood created widescreen aspect ratios to immerse the viewer in a more realistic experience and, possibly, to make the cinema experience more of a spectacle than what could not be achieved at home on a regular TV set. 16:9 is the international standard format of HDTV as used in Australia, Japan, and America, as well as in Europe.  
         [0024]     Recently, a move towards widescreen display systems is proceeding. If such systems are realized, a display screen with an aspect ratio of 4:3 will co-exist with an aspect ratio of 16:9.  
         [0025]     Referring to  FIG. 1 , an outer casing  100  in accordance with an exemplary embodiment is illustrated. The outer casing  100  is used to mount and secure a flexible screen  90  (as shown in  FIG. 8  and  FIG. 9 ) therein, and includes a main frame  10  and two side frames  20 . Each of two lateral sides of the screen  90  is attached to the corresponding side frame  20 . The side frames  20  are secured to two lateral sides of the main frame  10 , and each of the side frames  20  is securable at two different positions with respect to the main frame  10  to define different aspect ratios of a viewable size of the screen  90 .  
         [0026]     The main frame  10  includes a back plate  11 , a top margin  13 , and a bottom margin  15 . The back plate  11  is a rectangular plate backing the screen  90 . The top margin  13  and the bottom margin  15  are respectively bent from a top and a bottom of the back plate  11  to overlay a top edge and a bottom edge of the screen  90 .  
         [0027]     For ease of description, a transverse direction is defined along the top margin  13  and the bottom margin  15 , and a longitudinal direction is defined along a direction perpendicular to the top margin  13  and the bottom margin  15 . In addition, as the outer casing  100  is symmetrical with respect to an axis along the longitudinal direction thereof, hereunder only a left half of the outer casing  100  is described.  
         [0028]     The back plate  11  includes a stopping rib  111 , a first guiding rib  113 , a second guiding rib (not shown), a third guiding rib  114 , and a resisting block  116 . The stopping rib  111  is formed along the longitudinal direction of the outer casing  100 , and the first guiding rib  113 , the second guiding rib, and the third guiding rib  114  are formed along the transverse direction. The second guiding rib is located in a vicinity of the bottom margin  15 .  
         [0029]     Referring to  FIG. 2 , a detailed structure of a corner of the outer casing  100  is illustrated. A pair of mounting pieces  117 ,  118  is formed under the top margin  13 , and an opening  138  is defined in the top margin  13  between the mounting pieces  117 ,  118 . The mounting piece  118  is located in a vicinity of the third guiding rib  114 , and the mounting piece  117  is spaced away from the mounting piece  118 . Referring back to  FIG. 1 , a securing member  60  can be slideably received between the mounting pieces  117 ,  118 , with a first compression spring  67  sandwiched between the securing member  60  and the back plate  11  to provide a first restoration force along the longitudinal direction of the outer casing  100  when the securing member  60  is moved towards the top margin  13 .  
         [0030]     The side frame  20  includes an engaging member  30 , a reel  40 , and a side margin  50 . The reel  40  is mounted in the engaging member  30 , and sealed by the side margin  50 . The engaging member  30  is securable to the main frame  10  at two different positions to mount the screen  90  to the main frame  10  to define different viewable aspect ratios of the screen  90 .  
         [0031]     Referring also to  FIG. 3 , the engaging member  30  includes a main portion  31 , a guiding portion  32 , and an adjusting portion  33 . The guiding portion  32  and the adjusting portion  33  respectively extend perpendicularly from two ends of the main portion  31  to the main frame  10 . The main portion  31  is blockable by the stopping rib  111  to stop it moving across the stopping rib  111  once the side frame  20  is mounted to the main frame  10 . The main portion  31  defines a recess  316  to receive the reel  40  therein. The main portion  31  includes a pair of supporting plates  312 , and a locking piece  315 . The supporting plates  312  each with a notch  313  therein are formed next to each end of the main portion  31  respectively. The supporting plates  312  are used to support the reel  40 , and the notches  213  are used to accommodate the reel  40  therein. The locking piece  315  is formed next to one of the supporting plates  213 . A clasping hole  311  is defined in one distal end of the main portion  31  to engage with hooks (not shown) formed on the side margin  50  to mount the side margin  50  to the engaging member  30  and enclose the reel  40  in the recess  314  of the engaging member  30 . A cross section of the guiding portion  32  is in a reverse L shape, and can be coupled to the second guiding rib with a cross section in an L shape. The adjusting portion  33  is guided between the first guiding rib  113  and the third guiding rib  114  of the main frame  10 , and defines a first gap  331  and a second gap  332  along the transverse direction. The securing member  60  is selectively engageable in the first gap  331  or the second gap  332 . A housing  333  is formed at a distal end of the adjusting portion  33 . The housing  333  defines therein a void being used to receive a second compression spring  35  therein.  
         [0032]     Referring to  FIG. 4  and  FIG. 5 , the securing member  60  includes a main block  61 , a projecting block  63 , and a limiting arm  69 . The projecting block  63  is formed on the main block  61 , and the limiting arm  69  extends from a side of the main block  61  towards the longitudinal direction of the outer casing  100 . A pair of mounting grooves  613 ,  614  is defined at two lateral sides of the main block  61  respectively, to be engaged by the mounting pieces  117 ,  118  of the main frame  10 , to guide the securing member  60  to move along the longitudinal direction of the outer casing  100 . An operating piece  631  is formed on the projecting block  63  to extend through the opening  138 , in order to be reachable and moveable by a user. A mounting rod  651  extends through a hole  65  defined in the main block  61  and the projecting block  63 , along the longitudinal direction. The limiting arm  69  extends along the longitudinal direction to limit the adjusting portion  33  of the engaging member  30  between the limiting arm  69  and the back plate  11 . A wedging rod  691  extends backward from the limiting arm  69 . The wedging rod  691  can be selectively engaged in the first gap  331  or the second gap  332  to define the different viewable aspect ratios of the screen  90 .  
         [0033]     Referring to  FIG. 7 , the reel  40  includes a pair of positioning rings  41 , and a rollback mechanism  45 . The positioning rings  41  are sleeved on the reel  40 , and are respectively positioned next to the supporting plates  312  to stop the reel  40  moving along an axial direction of the reel  40 , i.e. the longitudinal direction of the outer casing  100 . The rollback mechanism  45  provides a rolling force that makes the reel  40  draw back the screen  90  once the reel  40  is rotated by an external force. The rollback mechanism  45  can be a mainspring for example. One end of the rollback mechanism  45  is attached to the reel  40 , and the other end of the rollback mechanism  45  is locked in place by the locking piece  315 .  
         [0034]     Referring to  FIG. 6 , an assembled structure of the outer casing  100  will be described in detail. The side frames  20  are attached to two opposite ends of the main frame  10 . The adjusting portion  33  of each side frame  20  is slideably engaged between the first guiding rib  113  and the third guiding rib  114  of the main frame  10  and the guiding portion  32  is slideably engaged with the second guiding rib. The second compression spring  35  is received in the housing  333  of the adjusting portion  33  and one end thereof abuts against the resisting block  116  to provide a second restoration force along the transverse direction. The securing member  60  is mounted between the mounting pieces  117  and  118  of the main frame  10 . The limiting arm  69  abuts on the adjusting portion  33  of the engaging member  30  to limit the adjusting portion  33  between the limiting arm  69  and the back plate  11 . The first compression spring  67  is received in the hole  65  of the securing member  60  with one end thereof being sleeved on the mounting rod  651  and the other end abutting against the joint between the top margin  13  and the back plate  11  of the main frame  10 . The operating piece  631  of the securing member  60  is received in the opening  138  in the top margin  13 . The wedging rod  691  of the securing member  60  is disengageable from the first gap  331  or the second gap  332  under an external force and engages into the first gap  331  or the second gap  332  under the first restoration force of the first compression spring  67 . Once the side frame  20  is released by the securing member  60 , the side frame  20  is forced to move in the transverse direction under the second restoration force of the second compression spring  35  until reaching and being blocked by the stopping rib  111 .  
         [0035]     Referring to  FIG. 8  and  FIG. 9 , the outer casing  100  is utilized in an electronic apparatus, for example a notebook computer  200 , as a projection display device thereof. The notebook computer  200  includes a base  240  and a display device  220  pivotably attached to the base  240 . The base  240  accommodates a projector (not shown) therein for projecting images to be displayed on the screen  90 . The notebook computer  200  is able to shift between a first aspect ratio and a second aspect ratio, wherein the second aspect ratio is larger than the first aspect ratio. The notebook computer  200  with the first aspect ratio is illustrated in  FIG. 8 , and the notebook computer  200  with the second aspect ratio is illustrated in  FIG. 9 .  
         [0036]     In the first aspect ratio, the wedging rods  691  of the securing members  60  are wedged in the corresponding first gaps  331  of the engaging members  30 , under the first restoration forces of the first compression springs  67 .  
         [0037]     When shifting from the first aspect ratio to the second aspect ratio, the operating pieces  631  of the securing members  60  in the openings  138  are triggered by manipulation of a user in a direction along the mounting pieces  117  and  118 , and the first compression springs  67  are compressed. The wedging rods  691  of the securing members  60  gradually move out from the first gaps  331  in the engaging members  30 . As the wedging rods  691  completely leave the first gaps  331 , the side frame  20  is forced to move outward along the first guiding rib  113  and the third guiding rib  114  with the aid of the second restoration forces of the second compression springs  35 , and the reels  40  rotate in the notches  313  against the rolling-up force of the rollback mechanisms  45  thus unrolling portions of the screen  90  to locate at opposite sides of the main frame  10 , that is, the unrolled portions of the screen  90  are revealed. When the engaging member  30  of the side frame  20  is moved to be blocked by the stopping rib  111  and the second gaps  332  in the side frame  20  align with the respective wedging rods  691  of the corresponding securing members  60 , the operating pieces  631  of the securing members  60  are released and the wedging rods  691  of the securing members  60  wedge into the corresponding second gaps  332  under the first restoration forces of the first compression springs  67 . The side frames  20  stop moving, and are fixed by the securing members  60 . The rollback mechanisms  45  apply tension forces to the reels  40 , keeping surfaces of the screen  90  smooth once positioned in place.  
         [0038]     After the above procedure, the aspect ratio of the display device of the notebook computer  200  is the second aspect ratio as shown in  FIG. 9 .  
         [0039]     When shifting from the second aspect ratio to the first aspect ratio, the operating pieces  631  are triggered once again, and the first compression springs  67  are compressed. The wedging rods  691  of the securing members  60  gradually move out from the second gaps  331  in the engaging members  30 . As the wedging rods  691  completely leave the second gaps  331 , the side frame  20  is forced to move inward along the first guiding rib  113  and the third guiding rib  114 , and the reels  40  rotate in the notches  313  thus rolling up the portions of the screen  90  located at opposite sides of the main frame  10  under the aid of the rollback mechanisms  45 , that is, the portions of the screen  90  located at opposite sides of the main frame  10  are concealed. When the engaging member  30  of the side frame  20  is moved to be blocked by edge of the main frame  10  and the first gaps  332  in the side frame  20  aligns with the respective wedging rods  691  of the corresponding securing members  60 , the securing members  60  are released and the wedging rods  691  of the securing members  60  wedge into the corresponding first gaps  332  under the first restoration forces of the first compression springs  67 . The side frames  20  stop moving, and are fixed by the securing members  60 . The rollback mechanisms  45  apply tension forces to the reels  40 , keeping viewing surfaces of the screen  90  smooth once in position.  
         [0040]     After the above procedure, the aspect ratio of the display device of the notebook computer  200  is the first aspect ratio as shown in  FIG. 8 .  
         [0041]     As described above, the outer casing  100  can change transverse length thereof to change the aspect ratio of the viewable surface of the screen  90 . Users can choose any desired aspect ratio. When needed, the adjusting portion  33  can define gaps in different positions thereof to change the length of the outer casing  100  along the transverse direction to present different sizes of viewable surfaces of the screen  90  thereby presenting different aspect ratios.  
         [0042]     The above outer casing  100  and the display device of the notebook computer  200  are symmetrical with respect to the axis along the longitudinal direction, and both of the side frames  20  are movable along the transverse direction to change the aspect ratio. An asymmetrical structure is an alternative modification of the above embodiment to carry out aspect ratio switch.  
         [0043]     The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to enable others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.