Abstract:
A fabricating apparatus for a light tunnel is provided, which comprises a core rod, a fixing block and a moving block. The light tunnel comprises a plurality of reflecting sheets, and each reflecting sheet leans on both a plurality of first bumps of the fixing block and a plurality of second bumps of the moving block to define a first inner profile and a second inner profile of the light tunnel, respectively. Thereby, the fabricating apparatus defines the inner scope of the light tunnel, and the inner scope of the light tunnel can be easily and stably controlled. Furthermore, a fabricating method for fabricating the light tunnel is also provided.

Description:
[0001]    This application claims priority to Chinese Utility Model Application No. 201120063843.8 filed on Feb. 23, 2011. 
       CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to a fabricating apparatus for a light tunnel and a fabricating method for fabricating a light tunnel, and more particularly, to a fabricating apparatus and a fabricating method that use inner dimensions of a light tunnel as a reference for fabricating the light tunnel. 
         [0005]    2. Descriptions of the Related Art 
         [0006]    With continuous advancement of projection technologies, the applications of projectors have become wider and consumers now have more options in purchasing projectors. Accordingly, the imaging quality requirements of the projectors have become increasingly heightened. A projector comprises a lot of optical components, and the characteristics of the individual optical components have different effects on the imaging quality of the projector. Projection luminance is known to be an important indicator of imaging quality, so most projection optics researches spend their research and development resources on improving projection luminance. A usual practice for improving the projection luminance adopted in this industry is to enhance the reliability of components of the projector&#39;s illumination system, to reduce the overall volume of the illumination system and to improve efficiency of the light source. 
         [0007]    The illumination system usually comprises a light source module, a lens, a light tunnel and the like. Generally, the light tunnel is used to uniformize the projection light, so it is able to control the projection luminance. Therefore, usually in practice, various parameters and the quality of the light tunnel are adjusted to improve the efficiency of the light source to improve the luminance of the images obtained. 
         [0008]    In more detail, the light tunnel is able to uniformize the light transmitted therethrough and project the light onto an active region of a spatial light modulation device to effectively avoid non-uniformity of luminance in a specific light path of the optical projection system. However, the control of the projector luminance is significantly affected by inner profile dimensions of the light tunnel. 
         [0009]    Most conventional fabricating processes of light tunnels fabricate a light tunnel through external positioning.  FIG. 1A  shows a schematic view of a fabricating apparatus  1  that uses outer dimensions of a light tunnel to position the light tunnel. During the fabrication process, a reflecting sheet stopping device  11  of the fabrication apparatus  1  is first adjusted to an appropriate position. Next, in reference to  FIG. 1B , reflecting sheets  12  for forming the light tunnel are placed in sequence, and an inhaling switch (not shown) is opened to adsorb the reflecting sheets  12  onto ports of corresponding inhaling pipes  13  as shown in  FIG. 1C . In reference to  FIG. 1D , a pressing block  15  is placed on the top of the light tunnel  14  and an external pressure that is exerted by an elastic pressing head  16  is adjusted, then the elastic pressuring head  16  is lowered to fix the reflecting sheets  12  of the light tunnel  14  together, and finally the reflecting sheets  12  are glued into form. 
         [0010]    For the fabricating process described above, a corresponding fabricating apparatus is first designed according to the outer dimensions of the light tunnel, and then the light tunnel is assembled by adjusting the fabricating apparatus, so that the inner profile dimensions of the light tunnel are guaranteed indirectly by use of the outer dimensions. However, this practice of fabricating a light tunnel through external positioning has several problems. Especially, because the inner profile dimensions of the light tunnel are determined through external positioning in the aforesaid practice, there are too many factors that have an effect on the inner profile dimensions, e.g., thicknesses of the reflecting sheets, inhaling forces of the inhaling pipes when the reflecting sheets are positioned, the operation mode and the flow process of adjusting the fabricating apparatus. Furthermore, this fabricating process is complex and makes it difficult to control the inner dimensions, which renders the product quality unstable in mass production. 
         [0011]    Accordingly, an urgent need exists in the art to provide a fabricating apparatus for a light tunnel which can improve the imaging luminance by effectively controlling the inner dimensions of the light tunnel. 
       SUMMARY OF THE INVENTION 
       [0012]    The primary objective of the present invention is to provide a fabricating apparatus for a light tunnel and a fabricating method for fabricating a light tunnel. The fabricating apparatus and the fabricating method of the present invention can effectively define inner dimensions of the light tunnel by defining an inner profile of the light tunnel to stabilize the quality of the light tunnels in mass production. 
         [0013]    To achieve the aforesaid objective, the present invention provides a fabricating apparatus for a light tunnel. The light tunnel has a first end portion and a second end portion that have a first inner profile and a second inner profile respectively; the first end portion and the second end portion define an axial length. The fabricating apparatus comprises a core rod, a fixing block and a moving block. The core rod has an inner axial portion and an adjustment portion. The inner axial portion has a first length, and the adjustment portion is adapted to make the first length equal to the axial length of the light tunnel. The fixing block is disposed at one end of the inner axial portion, and has a first surface and a plurality of first bumps disposed on the first surface. The plurality of first bumps defines the first inner profile. The moving block is disposed between the inner axial portion and the adjustment portion, and has a second surface and a plurality of second bumps disposed on the second surface. The plurality of second bumps defines the second inner profile, and the second surface is opposite to the first surface. 
         [0014]    To achieve the aforesaid objective, the present invention further provides a fabricating method for fabricating a light tunnel. The fabricating method adopts the fabricating apparatus described above. In detail, the fabricating method comprises: adjusting the adjustment portion of the fabricating apparatus to make the first length of the core rod equal to the axial length of the light tunnel; leaning a plurality of reflecting sheets on the first bumps and the second bumps; and fixing and connecting the reflecting sheets. 
         [0015]    The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIGS. 1A to 1D  are schematic views illustrating a conventional process of fabricating a light tunnel through external positioning; 
           [0017]      FIG. 2A  is a schematic view of an assembling apparatus according to a preferred embodiment of the present invention; 
           [0018]      FIG. 2B  is a schematic exploded view of the assembling apparatus shown in  FIG. 2A ; 
           [0019]      FIG. 3  is a schematic structural view of a light tunnel fabricated by use of the assembling apparatus shown in  FIG. 2A ; 
           [0020]      FIG. 4A  is a schematic view of a whole fabricating apparatus shown in  FIG. 2A ; and 
           [0021]      FIG. 4B  is a schematic view of the fabricating apparatus shown in  FIG. 2A  with a light tunnel being loaded thereon. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    In the following descriptions, the present invention will be explained with reference to embodiments thereof. However, these embodiments are not intended to limit the present invention to any specific environment, applications or particular implementations described in these embodiments. Therefore, the descriptions of these embodiments are only for purpose of illustration rather than to limit the present invention. It should be appreciated that in the following embodiments and the attached drawings, elements unrelated to the present invention are omitted from depiction; and dimensional relationships among individual elements in the attached drawings are illustrated only for ease of understanding, but not to limit the actual scale. 
         [0023]    A first preferred embodiment of the present invention is an assembling apparatus  2  for a light tunnel.  FIGS. 2A and 2B  illustrate a schematic assembled view and a schematic exploded view of the assembling apparatus  2  respectively, and  FIG. 3  shows a light tunnel fabricated by the assembling apparatus  2 .  FIG. 4A  is a schematic view of a whole fabricating apparatus  4  of this embodiment, and  FIG. 4B  is a schematic view, from another viewing angle, of the whole fabricating apparatus of this embodiment with an assembled light tunnel  3  being loaded thereon. 
         [0024]    In brief, the assembling apparatus  2  comprises a fabricating apparatus  4  and a support platform  6 . The light tunnel  3  has a first end portion  31  and a second end portion  32  located at two ends of the light tunnel  3  respectively. The first end portion  31  and the second end portion  32  has a first inner profile  311  and a second inner profile  321  respectively; and in this embodiment, both the first inner profile  311  and the second inner profile  321  are of a rectangular form and have equal dimensions. The first end portion  31  and the second end portion  32  located at the two ends of the light tunnel  3  define an axial length  33  of the light tunnel  3 . Generally, the light tunnel consists of a plurality of reflecting sheets, and in this embodiment, consists of four reflecting sheets  30 . Each of the reflecting sheets  30  is made of glass and plated with a highly reflective film on an inner surface thereof. Because the first inner profile  311  of the light tunnel  3  is the same as the second inner profile  321 , the four reflecting sheets  30  are rectangular reflecting sheets that are disposed in parallel in groups of two to form the light tunnel  3  with a hollow rectangular passage. As will be appreciated by those skilled in the art, the material, the number and the positions of the reflecting sheets may be altered depending on the practical design; and in other embodiments, the first inner profile may also be smaller than the second inner profile, i.e., the first inner profile and the second inner profile are both of a rectangular form but the first inner profile is smaller in area than the second inner profile to result in a tapered light tunnel. 
         [0025]    In references to both  FIGS. 4A and 4B  together, the fabricating apparatus  4  in this embodiment comprises a core rod  41 , a fixing block  42  and a moving block  43 . The core rod  41  has an inner axial portion  411  and an adjustment portion  412 . The inner axial portion  411  has a first length  413 , and the adjustment portion  412  can be adjusted to change the first length  413  of the inner axial portion  411  so that the first length  413  is equal to the axial length  33  of the light tunnel  3 . In this embodiment, the core rod  41  is made of a stainless steel. 
         [0026]    The fixing block  42  is disposed at one end of the axial portion  411 , and has a first surface  421  and two first bumps  422  disposed on the first surface  421 . The first bumps  422  abut against the reflecting sheets  30  of the light tunnel  3  to define the first inner profile  311 . 
         [0027]    The moving block  43  is disposed between the inner axial portion  411  and the adjustment portion  412  of the core rod  41 , and has a second surface  431  and two second bumps  432  disposed on the second surface  431 . The second bumps  432  abut against the reflecting sheets  30  of the light tunnel  3  to define the second inner profile  321 . Additionally, the second surface  431  is opposite to the first surface  421 . 
         [0028]    The adjustment portion  412  of the core rod  41  comprises a knob  412   a  and a first elastic device  412   b . In this embodiment, a spring is used as the first elastic device  412   b . One end of the first elastic device  412   b  abuts against the knob  412   a , and the other end thereof abuts against the moving block  43 . The knob  412   a  and the first elastic device  412   b  exert an axial force on the inner axial portion  411  to adjust and fix the position of the moving block  43  so that the first length  413  is equal to the axial length  33  of the light tunnel  3 . It shall be appreciated that the first elastic device is not limited to be a spring, but may also be some other elastic element depending on the practical needs. 
         [0029]    More specifically, the knob  412   a  may be turned to compress or release the first elastic device  412   b . When the first elastic device  412   b  is released, the moving block  43  is forced to move away from the fixing block  42  to increase the first length  413  of the inner axial portion  411 ; and conversely, when the first elastic device  412   b  is compressed, the moving block  43  moves towards the fixing block  42  to shorten the first length  413 . In this way, the adjustment portion  412  can be moved back and forth to change the first length  413  of the inner axial portion  411 . 
         [0030]    One end of the reflecting sheets  30  of the light tunnel  3  closely leans on the first bumps  422  of the first surface  421 , and the other end thereof closely leans on the second bumps  432  of the second surface  431 . The first bumps  422  and the second bumps  432  are designed and produced according to the inner dimensions of the light tunnel  3  so that the inner surfaces of the light tunnel  3  directly lean on both the first bumps  422  and the second bumps  432  to accurately control the inner dimensions of the light tunnel  3 . 
         [0031]    When a light tunnel is to be fabricated, the fabricating apparatus  4  and the support platform  6  of the assembling apparatus  2  are used at the same time. In references to both  FIGS. 2A and 2B , the fabricating apparatus  4  is fixed on the support platform  6 . The support platform  6  comprises a base plate  61 , a first leaning post  62 , a second leaning post  63  and four second elastic devices  64 . The base plate  61  has a bottom surface  611 . The first leaning post  62  is disposed at one end of the bottom surface  611  and abuts against the fixing block  42  of the fabricating apparatus  4 . The second leaning post  63  has a control shaft  631  and is disposed at the other end of the bottom surface  611 . The control shaft  631  of the second leaning post  63  abuts against the adjustment portion  412  of the fabricating apparatus  4  to adjust the first length  413  of the inner axial portion  411  (i.e., the axial length  33  of the light tunnel  3 ). 
         [0032]    The second elastic devices  64  are disposed on the first leaning post  62  to exert a normal force to the reflecting sheets  30  of the light tunnel  3  respectively so that the reflecting sheets  30  are fixed. Then, glue is applied to adhere the reflecting sheets  30  to each other so that they are fixedly connected together. In other embodiments, the second elastic devices  64  may also be disposed on the second leaning post  63 . In this embodiment, each of the second elastic devices  64  is a flat spring; of course, other implementations of the second elastic devices  64  will also be readily appreciated by those skilled in the art. 
         [0033]    According to the above descriptions, as compared to the conventional fabricating apparatus for a light tunnel, the fabricating apparatus of the present invention can accurately control and modulate the inner dimensions of the light tunnel through internal positioning so that the characteristics of the light tunnels can be controlled more easily to make the quality of the light tunnels more stable. 
         [0034]    The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.