Abstract:
A supporting unit ( 11 ) makes a reflection sheet ( 41 ) having a relatively low rigidity sag toward the side surface ( 13 S) of a base section ( 13 ) by supporting the reflection sheet ( 41 ) on a hem section ( 15 ), and at the same time, supports a diffusion sheet ( 43 ) having a relatively high rigidity on the leading edge of a shaft section ( 12 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a supporting unit for supporting a sheet, and to a sheet set which is a set of a sheet supported by such a supporting unit and the supporting unit itself. The invention also relates to an illuminating device (such as a backlight unit) provided with a sheet set, and to a display device (such as a liquid crystal display device) provided with such an illuminating device. 
       BACKGROUND ART 
       [0002]    When a liquid crystal display panel of a non-luminous type is used, a backlight unit (illuminating device) for supplying light to the liquid crystal display panel is provided in a liquid crystal display device. The backlight unit may adopt one of various types of light sources. For example, as a light source, a plurality of fluorescent lamps arranged side by side are provided 
         [0003]    In such a case, uneven distribution of light, called a “lamp image,” is observed in the light from the backlight unit. A lamp image denotes uneven distribution of light which makes the linear shapes of fluorescent lamps visible as a result of there being a large difference between the amount of light supplied to about right above the fluorescent lamps and the amount of light supplied to about right above the intervals between the fluorescent lamps. 
         [0004]    Some backlight units are designed to make the lamp image less visible, one example being the one disclosed in Patent Publication 1 listed below. In this backlight unit, as shown in  FIG. 15 , between adjacent fluorescent lamps  151 , a reflective member  191  having a triangular cross-sectional shape is fitted on a reflective surface  141  (in  FIG. 15 , the reference sign  143  represents a diffuser sheet). 
         [0005]    In this design provided with the reflective member  191 , part of the light from the fluorescent lamps  151  is reflected on the reflective member  191 , so that light is supplied to about right above the intervals between the fluorescent lamps  151  (see the solid-line arrows). This reduces the difference between the amount of light supplied to about right above the fluorescent lamps  151  and the amount of light supplied to about right above the intervals between the fluorescent lamps  151 , and thus makes the lamp image less visible. 
       LIST OF CITATIONS 
     Patent Literature 
       [0006]    Patent Publication 1: JP-A-2002-122863 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0007]    There are many kinds of reflective members like the reflective member  191 . To name a few, in one example, a reflective member  191  is formed as a separate piece from a reflective sheet as is conventionally provided; in another example, part of a metal chassis, covered by a reflective sheet, of a backlight unit is raised to form a reflective member  191 . 
         [0008]    Inconveniently, however, a reflective member  191  formed as a separate piece counts as an extra component, and thus leads to increased cost. On the other band, raising part of a metal backlight chassis requires a modification or the like to a comparatively large mold, and thus leads to increased cost. 
         [0009]    The present invention is made to overcome the inconveniences mentioned above, and it is an object of the invention to provide a component that is suitable to suppress, at low cost, uneven distribution of light in the light from an illuminating device, and to provided an illuminating device and a display device provided with such a component. 
       Solution to Problem 
       [0010]    The component that is suitable to suppress uneven distribution of light in the light from an illuminating device is a supporting unit that supports a sheet. The supporting unit includes a shaft portion and a base portion which supports the shaft portion. In this supporting unit, part of the shaft portion or part of the base portion supports, out of a first sheet (for example, a reflective sheet) and a second sheet (for example, an optical sheet), the first sheet having lower rigidity so as to let the first sheet sag toward the side face of the base portion, and the tip end of the shaft portion supports, out of the first and second sheets, the second sheet having higher rigidity. 
         [0011]    When this supporting unit is disposed between adjacent fluorescent lamps in an illuminating device, the fluorescent lamps are located by the side of the sagging part of the first sheet. When the first sheet is a reflective sheet, the light from the fluorescent lamps is reflected on the sagging part of the reflective sheet so as to travel to about right above the intervals between the fluorescent lamps. This reduces the difference between the amount of light supplied to about right above the fluorescent lamps and the amount of light supplied to about right above the intervals between the fluorescent lamps, and thus suppresses uneven light distribution such as a lamp image. 
         [0012]    An illuminating device is conventionally provided with a supporting member for supporting an optical sheet. Therefore, when the second sheet is an optical sheet, it can be said that the supporting unit is a modified version of a supporting member that is conventionally provided in an illuminating device. Thus, the illuminating device does not require an increased number of components, and this suppresses an increase in the cost of the illuminating device. Moreover, since the supporting unit is a comparatively small component, its modification can be achieved at comparatively low cost. 
         [0013]    It is preferable that the supporting unit, for example when the first sheet includes a hole, support the first and second sheets in the following manner: the shaft portion sticks through the hole in the first sheet so as to support, at its tip end, the second sheet, and the part of the shaft portion or the part of the base portion supports the edge of the hole so as to support the first sheet. 
         [0014]    The part of the shaft portion may be its tip end, or may be a first supporting portion which is formed as a protrusion that protrudes from the side face of the shaft portion. 
         [0015]    The part of the base portion may be a second supporting portion which is formed as a protrusion that protrudes from the side face of the base portion, or may be a fixing portion which supports the base end of the shaft portion and which is larger than the outer circumference of the base end. 
         [0016]    The base portion may support a plurality of such shaft portions. This design helps reduce the number of components, and helps reduce the cost of the illuminating device. 
         [0017]    It is preferable that the base portion be increasingly thick toward its bottom end opposite from its end supporting the shaft portion. With this design, the center of gravity of the supporting unit is closer to the base end of the base portion, and thus the first and second sheets are supported more stably. 
         [0018]    It is preferable that the shaft portion be increasingly thin toward its tip end. With this design, when the user views, for example, a display device provided with an illuminating device including the supporting unit, the tip end of the shaft portion is less visible. 
         [0019]    Also within the scope of the invention is a sheet set that includes: a supporting unit as described above; as the first said sheet, a reflective sheet which reflects received light; and as the second said sheet, an optical sheet which transmits received light. 
         [0020]    It is preferable that the reflective sheet be subjected to processing (for example, kiss-cutting or slitting) to allow the reflective sheet to bend along the boundary between the part of the reflective sheet that is supported by the part of the shaft portion or the part of the base portion and the part of the reflective sheet that sags toward the side face of the base portion. 
         [0021]    With this design, when the supporting unit is disposed, for example, between adjacent fluorescent lamps in an illuminating device, the reflective sheet easily sags toward the side face of the base portion. This ensures that the fluorescent lamps are located by the side of the sagging part of the reflective sheet, and that part of the light from the fluorescent lamps travels to about right above the intervals between the fluorescent lamps. This suppresses uneven light distribution in the illuminating device. 
         [0022]    Also within the scope of the invention is an illuminating device that includes: a sheet set as described above; a chassis to the bottom face of which the base portion of the supporting unit is fitted; and a light source (for example, a linear light source or a point light source) provided between the first and second said sheets to emit light. 
         [0023]    Also within the scope of the invention is a display device that includes: an illuminating device as described above; and a display panel to receive the light from the illuminating device. 
       ADVANTAGEOUS EFFECTS OF THE INVENTION 
       [0024]    According to the present invention, a supporting unit which is a small and hence inexpensive component is provided between adjacent fluorescent lamps so as to let a reflective sheet sag to be located by the side of the fluorescent lamps. Thus, the light reflected from the sagging part of the reflective sheet reaches about right above the intervals between the fluorescent lamps. As a result, the light from the illuminating device is free from uneven light distribution called lamp unevenness. It can thus be said that the supporting unit is a component that can suppress uneven light distribution in an illuminating device at low cost. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0025]    [ FIG. 1 ] is a partial perspective view showing a lamp clip gripping a fluorescent lamp and supporting units supporting a reflective sheet; 
           [0026]    [ FIG. 2 ] is a two-view diagram consisting of a plan view showing different members disposed on a backlight chassis and a sectional view cut along line A 1 -A 1 ′ in the plan view as seen from the direction of arrows; 
           [0027]    [ FIG. 3 ] is a two-view diagram consisting of a plan view showing different members disposed on a backlight chassis and a sectional view cut along line B 1 -B 1 ′ in the plan view as seen from the direction of arrows; 
           [0028]    [ FIG. 4 ] is a perspective view of a lamp clip; 
           [0029]    [ FIG. 5 ] is a perspective view of a supporting unit; 
           [0030]    [ FIG. 6 ] is a plan view of a backlight chassis; 
           [0031]    [ FIG. 7 ] is a plan view of a reflective sheet; 
           [0032]    [ FIG. 8 ] is a perspective view of a supporting unit; 
           [0033]    [ FIG. 9 ] is a two-view diagram showing how the supporting unit in  FIG. 8  supports the reflective sheet (the sectional view being one cut along line A 2 -A 2 ′ in the plan view as seen from the direction of arrows); 
           [0034]    [ FIG. 10 ] is an exploded perspective view of a liquid crystal display device; 
           [0035]    [ FIG. 11 ] is a perspective view of a supporting unit different from those in  FIGS. 5  and  8 ; 
           [0036]    [ FIG. 12 ] is a perspective view of a supporting unit different from those in  FIGS. 5 ,  8 , and  11 ; 
           [0037]    [ FIG. 13 ] is a perspective view of a supporting unit different from those in  FIGS. 5 ,  8 ,  11 , and  12 ; 
           [0038]    [ FIG. 14 ] is an exploded perspective view of a liquid crystal display device; and 
           [0039]    [ FIG. 15 ] is a sectional view of a conventional backlight unit. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiment 1 
       [0040]    An embodiment (Embodiment 1) of the present invention will be described below with reference to the accompanying drawings. For convenience&#39; sake, hatching and reference signs will occasionally be omitted, in which case reference should be made to other drawings. In the drawings, a black dot represents the direction perpendicular to the plane of paper. 
         [0041]      FIG. 14  is an exploded perspective view of a liquid crystal display device  89  as an example of a display device. As shown there, the liquid crystal display device  89  includes a liquid crystal display panel (display panel)  79 , a backlight unit (illuminating device)  69 , and a bezel BZ. 
         [0042]    The liquid crystal display panel  79  is composed of an active matrix substrate  71 , which includes switching elements such as TFTs (thin-film transistors), and a counter substrate  72 , which faces the active matrix substrate  71 , bonded together with a sealing member (not shown). The gap between the two substrates  71  and  72  is filled with liquid crystal (not shown) (in addition, polarizer films  73  and  73  are fitted to the active matrix substrate  71  and the counter substrate  72  so as to sandwich these from opposite sides). 
         [0043]    The liquid crystal display panel  79  is of a non-luminous type, and therefore performs its displaying function by receiving the light (backlight) from the backlight unit  69 . Thus, making the light from the backlight unit  69  illuminate the entire surface of the liquid crystal display panel  79  as evenly as possible helps improve the display quality of the liquid crystal display panel  79 . 
         [0044]    The backlight unit  69  includes fluorescent lamps (light sources, linear light sources)  51 , lamp holders  52 , a backlight chassis  53 , a reflective sheet  41 , and an optical sheet stack  42  (a diffuser sheet  43  and lens sheets  44  and  45 ). 
         [0045]    Although not shown in  FIG. 14 , the backlight unit  69  further includes lamp clips  21 , which grip the fluorescent lamps  51  and fit them to the backlight chassis  53 , and support units  11 , which on one hand support the optical sheet stack  42  and on the other hand also support the reflective sheet  41  (see  FIG. 1 , which will be discussed later). 
         [0046]    The fluorescent lamps  51  are linear (bar-shaped, cylindrical, etc.) light sources, and a plurality of them are provided inside the backlight unit  69  (for convenience&#39;s sake, however, not all of them are necessarily shown in all the relevant drawings). 
         [0047]    The fluorescent lamps  51  may be of any type; they may be, for example, cold cathode lamps or hot cathode lamps. In the following description, the direction in which the fluorescent lamps  51  are arranged side by side will be referred to as X direction, the direction in which the fluorescent lamps  51  extend will be referred to as Y direction, and the direction perpendicular to both X and Y directions will be referred to as Z direction. 
         [0048]    The lamp holders  52  are a pair of block-like members, and hold the fluorescent lamps  51  and the optical sheet stack  42 . More specifically, the lamp holders  52  support the fluorescent lamps  51 , each of the former at a different end of the latter, and thereby permit the fluorescent lamps  51  to be provided in the backlight unit  69 . Moreover, the lamp holders  52  support, at their face facing the liquid crystal display panel  79 , the diffuser sheet  43 , on top of which the lens sheets  44  and  45  are provided; thus, the diffuser sheet  43  and the lens sheets  44  and  45  are provided in the backlight unit  69 . 
         [0049]    The backlight chassis (chassis)  53  is a housing member having a bottom face  53 B and walls (opposite walls) SW and SW, the latter rising from the former and being opposite each other. The backlight chassis  53  houses the fluorescent lamps  51  and other components. 
         [0050]    The backlight chassis  53  has holes (chassis holes  53 L) for the fitting of lamp clips  21  and holes (chassis holes  53 U) for the fitting of support units  11 . The chassis holes  53 L and  53 U will be discussed in detail later. 
         [0051]    The reflective sheet  41  is a reflective member which covers the bottom face  53 B of the backlight chassis  53 . The reflective sheet  41  reflects the light from the fluorescent lamps  51  disposed inside the backlight chassis  53 . More specifically, the reflective sheet  41  reflects part of the light emanating radially from the fluorescent lamps  51  (the light traveling radially from each fluorescent lamp  51  as a center) so as to direct it to the open face of the backlight chassis  53 . 
         [0052]    The reflective sheet  41  is supported by support units  11 , which will be discussed later, and as a result sags from place to place. For convenience&#39; sake, these sags are not shown in  FIG. 14 . The reflective sheet  41  has two kinds of holes  41 U and  41 L, one kind (sheet holes  41 U) corresponding to support units  11 , and the other kind (sheet holes  41 L) corresponding to lamp clips  21 . Details will be discussed later. 
         [0053]    The optical sheet stack  42  transmits the light from the fluorescent lamps  51 , and includes a diffuser sheet  43  and lens sheets  44  and  45 . 
         [0054]    The diffuser sheet  43  is a member formed of a resin that has the functions of scattering and diffusing light, examples of such resins including polyethylene terephthalate. The diffuser sheet (optical sheet)  43  is disposed so as to cover the fluorescent lamps  51  arranged side by side on the bottom face  53 B of the backlight chassis  53 . Thus, when the light from the fluorescent lamps  51  enters the diffuser sheet  43 , the light is scattered and diffused so as to distribute evenly across the plane of the sheet. 
         [0055]    The lens sheet  44  is, for example, an optical sheet that has the shape of prisms on the sheet surface to narrow the directivity of light, and is disposed so as to cover the diffuser sheet  43 . Thus, the lens sheet (optical sheet)  44  condenses the light emanating from the diffuser sheet  43  and thereby increases the luminance. 
         [0056]    The lens sheet  45  is disposed so as to cover the lens sheet  44 , and is an optical sheet that transmits a light component polarized in one direction and reflects a light component polarized in the direction perpendicular to the direction in which the transmitted polarized light component is polarized. The lens sheet (optical sheet)  45  reflects, for reuse, the polarized component absorbed by the diffuser film  73 , and thereby increases the luminance on the liquid crystal display panel  79 . 
         [0057]    The bezel BZ serves as part of the exterior of the liquid crystal display device  89 , and is a member that houses the backlight unit  69  and the liquid crystal display panel  79  disposed on top of the backlight unit  69 . 
         [0058]    In the backlight unit  69  designed as described above, the fluorescent lamps  51  arranged side by side emit light by being supplied with an alternating-current signal from an inverter (not shown). The light reaches the diffuser sheet  43  directly or after being reflected on the reflective sheet  41 . The light that has reached the diffuser sheet  43  then, while being diffused, passes through the lens sheets  44  and  45  so as to leave them as backlight with increased luminance. The backlight then reaches the liquid crystal display panel  79 , which displays an image. 
         [0059]    Now, how lamp clips  21  and support units  11 , which are omitted in  FIG. 14 , support (hold) the reflective sheet  41  will be described with reference to  FIGS. 1 to 7  (the support units  11  along with the reflective sheet and the diffuser sheet  43  may be collectively called a sheet set). 
         [0060]      FIG. 4  is a perspective view of a lamp clip  21 , and  FIG. 5  is a perspective view of a support unit  11 .  FIG. 6  is a plan view of the backlight chassis  53 , and  FIG. 7  is a plan view of the reflective sheet  41 . 
         [0061]      FIG. 1  is a partial perspective view showing a lamp clip  21  gripping a fluorescent lamp  51  and support units  11  supporting the reflective sheet  41 .  FIG. 2  is a two-view diagram consisting of a plan view of different members disposed on the backlight chassis  53  and a sectional view cut along line A 1 -A 1 ′ in the plan view as seen from the direction of arrows.  FIG. 3  is, like  FIG. 2 , a two-view diagram consisting of a plan view of different members disposed on the backlight chassis  53  and a sectional view cut along line B 1 -B 1 ′ in the plan view as seen from the direction of arrows. For convenience&#39; sake, in the sectional views in  FIGS. 2 and 3 , the diffuser sheet  43  is shown as well. Also for convenience&#39; sake, lines A 1 -A 1 ′ and B 1 -B 1 ′ are shown in  FIG. 1  as well. 
         [0062]    The lamp clips  21  are members that grip the fluorescent lamps  51  and fix them to the backlight chassis  53 , and as shown in  FIG. 4  each lamp clip  21  includes a clip portion  22 , a pillar portion  23 , and a clip anchor portion  24 . 
         [0063]    The clip portion  22  is a member that grips the side face of a fluorescent lamp  51 , which is bar-shaped (cylindrical, etc.). Accordingly, the clip portion  22  has the shape of a cylindrical pipe having a cut  22 C formed in the side face for the gripping of the cylindrical fluorescent lamp  51 . To enable the clip portion  22  to grip the fluorescent lamp  51 , the inner diameter of the clip portion  22  is made slightly larger than the outer diameter of the fluorescent lamp  51 . 
         [0064]    The clip portion  22  has outward-bent portions  22 P and  22 P which form the edges of the cut  22 C. The outward-bent portions  22 P and  22 P are increasingly apart from each other away from the inner-diameter center IC (see  FIG. 3 ) of the clip portion  22 . Thus, the width of the cut  22 C (the interval between the outward-bent portions  22 P and  22 P) is increasingly large away from the inner-diameter center IC (see  FIG. 3 ) of the clip portion  22 . 
         [0065]    The outward-bent portions  22 P and  22 P are formed of resin, and are thus elastic. Accordingly, when a fluorescent lamp  51  is pressed against them at the cut  22 C, the outward-bent portions  22 P and  22 P come farther apart from each other owing to their elasticity. This allows the fluorescent lamp  51  to fit into the clip portion  22  easily. 
         [0066]    Once the fluorescent lamp  51  fits into the clip portion  22 , the outward-bent portions  22 P and  22 P, which have just had the cut  22 C widened temporarily, restore their original state (the state in which they are not obstructed by the fluorescent lamp  51 ) owing to their elasticity. Now the outward-bent portions  22 P and  22 P come closer to each other, and press against the fluorescent lamp  51 . Thus, the fluorescent lamp  51  is stably gripped so as not to come off the clip portion  22 . 
         [0067]    The pillar portion  23 , at its tip end, supports the clip portion  22  and, at its base end, connects to the clip anchor portion  24 . 
         [0068]    The clip anchor portion  24  is, as shown in  FIG. 6 , a member that hooks on the edge of a hole (a chassis hole  53 L) formed in the bottom face  53 B of the backlight chassis  53 . Thus, by hooking on the edge of the chassis hole  53 L, the clip anchor portion  24  keeps the lamp clip  21  in fixed position not only in directions along the plane of the bottom face  53 B but also in the direction rising from (such as perpendicular to) the bottom face  53 B of the backlight chassis  53 . 
         [0069]    Next, the support units  11  will be described. The support units  11  serve to support the reflective sheet  41  while letting it sag from place to place, and also to support the optical sheet stack  42 . As shown in  FIG. 5 , the support units  11  each include a shaft portion  12 , a base portion  13 , and a unit anchor portion  14 . 
         [0070]    The shaft portion  12  is a conic bar-like member tapering off toward its tip end  12 T. The shaft portion  12 , at its tip end  12 T, supports the optical sheet stack  42 . The shaft portion  12  further includes, at its base end  12 B, a brim portion (a first supporting portion)  15  formed as a protrusion protruding from the side face  12 S of the shaft portion  12  itself. The brim portion  15  is formed so as to surround the outer circumference of the shaft portion  12 , and thus forms a ring-shaped disc. On this brim portion  15 , the shaft portion  12  (and hence the support unit  11 ) supports the reflective sheet  41  (details will be discussed later). 
         [0071]    The base portion  13  is a cylindrical bar-like member which supports the base end  12 B of the shaft portion  12 . As shown in  FIG. 5 , the size around the cylinder at the base portion  13  is smaller than the size around the outer circumference of the brim portion  15 , which has the shape of a disc hollow at the center (the diameter of the base portion  13  about its pillar direction is smaller than the diameter of the brim portion  15 ). On the other hand, the size around the cylinder at the base portion  13  is approximately equal to the size around the shaft at the base end  12 B of the shaft portion  12 . 
         [0072]    The unit anchor portion  14 , like the clip anchor portion  24  included in the lamp clip  21 , is a member that hooks on the edge of a hole (a chassis hole  53 U; see  FIG. 6 ) formed in the bottom face  53 B of the backlight chassis  53 . Thus, by hooking on the edge of the chassis hole  53 U, the unit anchor portion  14  keeps the support unit  11  in fixed position not only in directions along the plane of the bottom face  53 B but also in the direction rising from (such as perpendicular to) the bottom face  53 B of the backlight chassis  53 . 
         [0073]    Next, the backlight chassis  53  will be described with reference to  FIG. 6 . The backlight chassis  53  has chassis holes  53 L into which the clip anchor portions  24  of the lamp clips  21  are fitted and chassis holes  53 U into which the unit anchor portions  14  of the support units  11  are fitted. 
         [0074]    The chassis holes  53 L are, for example, holes for the fitting of the lamp clips  21  which grip the fluorescent lamps  51  at their opposite ends. Accordingly, as will be seen in  FIG. 6 , where the shapes of the fluorescent lamps  51  overlapping the bottom face  53 B of the backlight chassis  53  are indicated by broken lines (the reference sign for the fluorescent lamps  51  being used to identify their shapes as well), the chassis holes  53 L are formed in divided rows at one and the other ends of the fluorescent lamps  51 . 
         [0075]    Thus, the fluorescent lamps  51  are, near their opposite ends, gripped by the lamp clips  21  and are thereby fitted to the backlight chassis  53 . Here, the fluorescent lamps  51  are arranged in columns (side by side in X direction), and accordingly the chassis holes  53 L are arranged in a matrix. 
         [0076]    So that the support units  11  may not overlap the fluorescent lamps  51 , the chassis holes  53 U are formed at locations displaced from the chassis holes  53 L, for example between adjacent fluorescent lamps  51 . More specifically, a plurality of chassis holes  53 U are formed between adjacent fluorescent lamps  51  in X direction, along the direction in which the fluorescent lamps  51  extend (Y direction). Thus, the chassis holes  53 U too are arranged in a matrix (the outermost chassis holes  53 B in X direction are not arranged between adjacent fluorescent lamps  51 ). 
         [0077]    Next, the reflective sheet  41  will be described in detail with reference to  FIG. 7 . The reflective sheet  41  has two kinds of holes  41 U and  41 L and half-cut lines  41 N formed by kiss-cutting. 
         [0078]    The sheet holes  41 U of the first kind are sheet holes  41 U through which the shaft portions  12  of the support units  11  pass. What is particular about the sheet holes  41 U is that they have such a size (diameter) as to permit the shaft portions  12  to pass through them but not the brim portions  15 . 
         [0079]    Thus, the support units  11  are, as shown in  FIGS. 1 and 2 , so designed that the shaft portions  12  pass through the reflective sheet  41  from its non-reflective surface  41 V side and that the unit anchor portions  14  fit into the chassis holes  53 U in the backlight chassis  53 . Thus, the brim portions  15  support the edges of the sheet holes  41 U, and keep the reflective sheet  41  apart from the bottom face  53 B of the backlight chassis  53 . 
         [0080]    As shown in  FIGS. 6 and 7 , the number of sheet holes  41 U is equal to the number of chassis holes  53 U, and the sheet holes  41 U and the chassis holes  53 U are both arranged in a matrix. 
         [0081]    However, when the interval WB between adjacent chassis holes  53 U in X direction is compared with the interval WS between adjacent sheet holes  41 U, the interval WS is greater than the interval WB. With this design, the parts of the reflective sheet  41  that are located between adjacent sheet holes  41 U in X direction (the parts of the reflective sheet  41  each including the interval WU) tend to sag toward the backlight chassis  53  under self-weight (the rigidity of the reflective sheet  41  is comparatively low to allow it to sag, and is, for example, lower than the rigidity of the diffuser sheet  43 ). 
         [0082]    Such sagging of the reflective sheet  41  is ensured by the half-cut lines  41 N formed by kiss-cutting. The half-cut lines  41 N extend in Y direction, and are arranged side by side in X direction as if dividing between the sheet holes  41 U arranged in Y direction and the sheet holes  41 L likewise arranged in Y direction. The half-cut lines  41 N are formed by half-cutting from the reflective surface  41 R side (that is, no cutting is done on the non-reflective surface  41 V). 
         [0083]    This ensures that, as shown in  FIGS. 1 to 3 , the parts of the reflective sheet  41  that are located between adjacent sheet holes  41 U in X direction sag toward the backlight chassis  53  along the half-cut lines  41 N so as to form troughs VG. Thus, it may be said that the half-cut lines  41 N serve to bend the reflective sheet  41  along the boundaries between the parts of the reflective sheet  41  that are supported on the brim portions  15  and the parts of the reflective sheet  41  that sag toward the side faces  13 S of the base portions  13  of the support units  11 . 
         [0084]    The half-cut lines  41 N may be formed otherwise than by kiss-cutting; they may instead be formed by, for example, slit-cutting (perforation). 
         [0085]    The sheet holes  41 L of the second kind are sheet holes  41 L that are formed at the troughs VG formed in the reflective sheet  41  (that is, the intervals produced as a result of groups of sheet holes  41 U, each group consisting of sheet holes  41 U arranged in Y direction, being arranged in X direction). These sheet holes  41 L permit the clip anchor portions  24  of the lamp clips  21  to pass through them. What is particular about the sheet holes  41 L is that they have such a size as to permit the clip anchor portions  24  to pass through them but not the base portions  13 . 
         [0086]    Thus, the lamp clips  21  are so designed that the clip anchor portions  24  pass through the reflective sheet  41  from its reflective surface  41 R side and that the clip anchor portions  24  fit into the chassis holes  53 L in the backlight chassis  53 . Thus, the clip portions  22  of the lamp clips  21  are located above the reflective surface  41 R of the reflective sheet  41 , and the fluorescent lamps  51  are gripped in the clip portions  22 . 
         [0087]    The lamp clips  21 , by being located above the reflective surface  41 R, presses the reflective sheet  41 . This is achieved in the following manner. First, the unit anchor portions  14  are fitted into the chassis hole  53 U so that the support units  11  are kept in fixed position on the bottom face  53 B of the backlight chassis  53 . Next, the reflective sheet  41  is placed over the bottom face  53 B of the backlight chassis  53 , where now the support units  11  are arranged all across, with the non-reflective surface  41 V of the reflective sheet  41  facing the bottom face  53 B of the backlight chassis  53 . 
         [0088]    More specifically, the reflective sheet  41  is placed over the bottom face  53 B of the backlight chassis  53  with the shaft portions  12  of the support units  11  passing through the sheet holes  41 U in the reflective sheet  41 . Then, since the interval (interval WS) between adjacent sheet holes  41 U is greater than the interval (interval WB) between adjacent support units  11  in X direction, when the sheet holes  41 U fit around the shaft portions  12  of the support units  11 , a force acts on the parts of the reflective sheet  41  corresponding to the interval WS. 
         [0089]    Then, those parts of the reflective sheet  41  sag along the half-cut lines  41 N formed from the reflective surface  41 R side. More specifically, those parts of the reflective sheet  41  sink toward the backlight chassis  53  so as to form troughs VG. In these troughs VG, the sheet holes  41 L are formed. 
         [0090]    Then, the clip anchor portions  24  of the lamp clips  21  are passed through the reflective sheet  41  from its reflective surface  41 R side, and are then fitted into the chassis holes  53 L in the backlight chassis  53 . Now, the clip portions  22  of the lamp clips  21  are located above the reflective surface  41 R of the reflective sheet  41 , and then the fluorescent lamps  51  are gripped in the clip portions  22 . 
         [0091]    With this design, as shown in  FIG. 2 , the parts of the optical sheet stack  42  about right above the fluorescent lamps  51  (the regions of the optical sheet stack  42  that overlap the fluorescent lamps  51  in Z direction) are supplied with light (direct light) directly from the fluorescent lamps  51  without a detour via the reflective sheet  41  (see light L 1 ). 
         [0092]    On the other hand, the parts of the reflective sheet  41  that sag toward the side faces  13 S of the base portions  13  are located by the side of the fluorescent lamps  51 . Thus, the light reflected from those sagging parts of the reflective sheet  41  is supplied to the parts of the optical sheet stack  42  about right above the support units  11  (see light L 2 ). More specifically, part of the light from the fluorescent lamp  51  strikes and is then reflected from the parts of the reflective sheet  41  that are located between adjacent support units  11  and sag to form troughs VG. The reflected light then travels toward the parts of the optical sheet stack  42  about right above the support units  11 . 
         [0093]    Then, on the plane of the optical sheet stack  42 , both the regions overlapping the fluorescent lamps  51  and the regions overlapping the intervals between the fluorescent lamps  51  are supplied with light. Thus, uneven light distribution (visibility of the linear shapes of the lamp holders  52 ; a lamp image) resulting from excessive light being supplied to the parts overlapping the fluorescent lamps  51  on the plane of the optical sheet stack  42  is suppressed. 
         [0094]    As described above, the support units  11 , which make the reflective sheet  41  sag for the prevention of uneven light distribution, not only support the reflective sheet  41  but also support the optical sheet stack  42  (directly, the diffuser sheet  43 ). That is, on one hand, the support units  11 , at their brim portions  15 , support the reflective sheet  41 , which has relatively low rigidity, to make it sag toward the side faces  13 S of the base portions  13 ; on the other hand, the support units  11 , at the tips of their shaft portions  12 , support the diffuser sheet  43 , which has relatively high rigidity. 
         [0095]    In other words, it can be said that, here, the support units  11 , which are generally provided to support the optical sheet stack  42  including the diffuser sheet  43 , has been improved to include a new part (the brim portions  15 ) to support the reflective sheet  41 . Accordingly, the backlight unit  69  does not need to be provided with a separate reflective member for supplying light to about right above the support units  11  in order to suppress uneven light distribution such as a lamp image. This reduces the cost of the backlight unit  69 , and hence the cost of the liquid crystal display device  89 . 
         [0096]    Moreover, to make the reflective sheet  41  sag so as to enclose the fluorescent lamps  51 , the support units  11  raise, at their brim portions  15 , the edges of the sheet holes  41 U in the reflective sheet  41 . Thus, the support units  11  only touch parts of the reflective sheet  41  (the edges of the sheet holes  41 U), and do not make planer contact across a large area; likewise, the lamp clips  21  only touch parts of the reflective sheet  41  (the edges of the sheet holes  41 L), and do not make planer contact across a large area. 
         [0097]    That is, the fixing of the reflective sheet  41  with respect to the bottom face  53 B of the backlight chassis  53  is achieved by the contact of the lamp clips  21  with the bottom face  53 B of the backlight chassis  53  via the reflective sheet  41  and the contact of the support units  11 , which are fixed to the backlight chassis  53 , with the reflective sheet  41 . With this design, even when there is a change in the size of the reflective sheet  41  (due to variations in the dimensions of the reflective sheet  41 , or temperature-induced contraction or the like of the reflective sheet  41 ), the reflective sheet  41  is surely fixed with respect to the bottom face  53 B of the backlight chassis  53  (that is, various factors for variations in the reflective sheet  41  can be tolerated). In addition, the reflective sheet  41  is less prone to become wrinkled. 
         [0098]    For example, in some designs, planar contact across a large area between the reflective sheet and the bottom face of the backlight chassis is exploited to fix the reflective sheet to the bottom face of the backlight chassis. In other designs, parts of the backlight chassis located between adjacent fluorescent lamps are raised, and the reflective sheet is fixed in close contact with those raised parts, so that the parts of the reflective sheet fixed in close contact function as a reflective member which supplies light to about right above the intervals between adjacent fluorescent lamps. 
         [0099]    In these designs, if there is a change in the size of the reflective sheet, that makes it difficult to fix the reflective sheet with respect to the bottom face of the backlight chassis. In addition, the reflective sheet is prone to become wrinkled. 
         [0100]    These inconveniences, however, are less likely to occur in a design where the fixing of the reflective sheet  41  with respect to the bottom face  53 B of the backlight chassis  53  is achieved by local contact, namely the contact of the lamp clips  21  with the bottom face  53 B of the backlight chassis  53  via the reflective sheet  41  and the contact between the support units  11  fixed to the backlight chassis  53  with the reflective sheet  41 . 
       Embodiment 2  
       [0101]    Another embodiment (Embodiment 2) of the invention will be described below. Such members in Embodiment 2 as have similar functions to the corresponding members in Embodiment 1 will be identified by the same reference signs, and no overlapping description will be repeated. 
         [0102]    In Embodiment 1, the reflective sheet  41  includes the sheet holes  41 U, and the support units  11 , by sticking the shaft portions  12  through sheet holes  41 U, support, at the tip ends  12 T of the shaft portions  12 , the optical sheet stack  42  including the diffuser sheet  43 . On the other hand, the support units  11 , at the brim portions  15 , which are parts of the shaft portions  12 , support the edges of the sheet holes  41 U and thereby support the reflective sheet  41 . 
         [0103]    Instead, the support units  11  may, at parts of the shaft portions  12  other than the brim portions  15 , support the reflective sheet  41 . Specifically, the support units  11  can, at the tip ends  12 T of the shaft portions  12 , support the reflective sheet  41 . Such a design will now be described with reference to  FIGS. 8 to 10 . 
         [0104]      FIG. 8  is a perspective view of a support unit  11 .  FIG. 9  is a two-view diagram showing how the support unit  11  in  FIG. 8  supports the reflective sheet  41  (the two views are presented in a similar manner as in  FIG. 2 ). 
         [0105]    As shown in  FIG. 8 , the support unit  11  here has no brim portion  15 . As shown in  FIG. 9 , the support units  11 , at the tip ends  12 T of their shaft portions  12 , support the reflective sheet  41  from its non-reflective surface  41 V side, and in addition, via the reflective sheet  41 , support the diffuser sheet  43  as well. Also with this design, the support units  11  support the reflective sheet  41 , which has comparatively low rigidity, and makes it sag toward the side faces  13 S of the base portions  13 . In addition, the support units  11 , at the tip ends of their shaft portions  12 , also support the diffuser sheet  43 , which has relatively high rigidity. 
         [0106]    Thus, also with this design, as shown in  FIG. 9 , the parts of the optical sheet stack  42  located about right above the fluorescent lamps  51  are supplied with light (direct light L 1 ) from the fluorescent lamps  51  directly without a detour via the reflective sheet  41 , and the parts of the optical sheet stack  42  about right above the support units  11  are supplied with reflected light L 2  from the fluorescent lamps  51  via the reflective sheet  41 . 
         [0107]    Then, on the plane of the optical sheet stack  42 , both the regions overlapping the fluorescent lamps  51  and the regions overlapping the intervals between the fluorescent lamps  51  are supplied with light, and thus uneven light distribution is suppressed. 
         [0108]    In a case where, as shown in  FIG. 9 , the support units  11 , at the tip ends  12 T of the shaft portions  12 , support the reflective sheet  41 , the parts of the reflective sheet  41  that sag toward the side faces  13 S of the base portions  13  of the support units  11  make contact with the diffuser sheet  43 , and spaces are formed that are surrounded by the diffuser sheet  43  and the reflective sheet  41 . When the fluorescent lamps  51  as light sources are disposed in those spaces, the light from one fluorescent lamp  51  is less likely to reach the space in which another fluorescent lamp  51  is housed. 
         [0109]    Accordingly, when this phenomenon is exploited, it is preferable that the backlight unit  69  be one in which, as shown in  FIG. 10 , a plurality of LEDs (point light sources, light-emitting elements)  55  are arranged all across in a matrix. The reason is that, with such a backlight unit  69 , the emitted light can be controlled for each LED  55 , and thus it is possible to partly illuminate the display region of the liquid crystal display device  89  (a backlight unit  79  of this type is called a backlight unit  79  of an active area type). 
         [0110]    Then, to partly illuminate the display region of the liquid crystal display device  89  more accurately, it is preferable that the light from one LED  55  not reach the region illuminated by another LED  55 . Thus, in a backlight unit  69  of an active area type, it is preferable that, with support units  11  like that shown in  FIG. 8 , the reflective sheet  41  be raised to divide the regions illuminated by the light of the individual LEDs  55 . 
         [0111]    In such a backlight unit  69 , the LEDs  55  are mounted, through the sheet holes  41 L, on a mounting circuit board  56  covered with the reflective sheet  41 . Thus, the LEDs  55  directly press the reflective sheet  41  (in the backlight unit  69  of Embodiment 1, the fluorescent lamps  51  indirectly press the reflective sheet  41  via the lamp clips  21 . 
       Other Embodiments 
       [0112]    It should be understood that the present invention is not limited by the embodiments described above and accommodate many modifications and variations without departing from the spirit of the invention. 
         [0113]    For example, the shape of the support unit  11  is not limited to that shown in  FIG. 5  where part of the shaft portion  12  is formed into a brim portion  15 . For example, as shown in  FIG. 11 , the top face  13 U of the base portion  13  supporting the base end  12 B of the shaft portion  12  may have a larger size than the outer circumference of the base end  12 B of the shaft portion  12 . With this design, the top face  13 U (a fixing portion), which is part of the base portion  13  and which keeps the base end  12 B of the shaft portion  12  in fixed position, can support the edge of the sheet hole  41 U in the reflective sheet  41 . 
         [0114]    The outer circumference does not necessarily have to be circular like the brim portion  15  of the shaft portion  12  in  FIG. 5  and the top face  13 U of the base portion  13  in  FIG. 11 . For example, as shown in  FIG. 12 , part of the shaft portion  12  near its base end  12 B may be formed into a block-shaped projection  16  (a first supporting portion). 
         [0115]    In short, it is at least necessary that, when the tip end  12 T of the shaft portion  12  has passed through the sheet hole  41 U in the reflective sheet  41  and the base end  12 B is now about to pass through the sheet hole  41 U, a brim portion  15  or a projection portion  16  formed as a protrusion protruding from the side face  12 S of the shaft portion  12  support the edge of the sheet hole  41 U. 
         [0116]    In the above description, the brim portion  15  and the projection portion  16  are formed by part of the shaft portion  12  near its base end  12 B. This should not be understood as a limitation. For example, the brim portion  15  and the projection portion  16  may be formed of part of the base portion  13  near its top face  13 U. In short, the brim portion  15  and the projection portion  16  may instead be formed as a protrusion protruding from the side face  13 S of the base portion  13  (the brim portion  15  and the projection portion  16  so formed are called a second supporting portion). 
         [0117]    In the support unit  11 , the shaft portion  12  and the base portion  13  may be formed as a single piece together, or as separate pieces to be combined together. The brim portion  15  or the projection portion  16  may be formed as a single piece with, or a separate piece to be combined with, the shaft portion  12 . Likewise, the brim portion  15  or the projection portion  16  may be formed as a single piece with, or a separate piece to be combined with, the base portion  13 . 
         [0118]    The support unit  11  may be composed of, as shown in  FIG. 13 , a base portion  13  that extends linearly like the fluorescent lamp  51  and a plurality of shaft portions  12  that are fitted to it. This design helps reduce the number of components, and thus facilitates the production of the backlight unit  69  (and hence the liquid crystal display device  89 ). 
         [0119]    As shown in  FIGS. 11 and 13 , the base portion  13  may be increasingly thick toward its bottom face (bottom end)  13 B opposite from its top face (end)  13 U supporting the shaft portion  12 . With this design, the center of gravity of the support unit  11  is closer to the bottom face  53 B of the backlight chassis  53  (that is, the center of gravity of the support unit  11  is closer to the bottom face  13 B of the base portion  13 ), and thus the optical sheet stack  42  and the reflective sheet  41  can be supported more stably. 
         [0120]    The shaft portion  12  of the support unit  11  may be increasingly thin toward its tip end  12 T. With this design, when the user views the liquid crystal display panel  79  from the front, the tip end  12 T of the shaft portion  12  is less visible. 
         [0121]    Although in the above description the shaft portion  12  of the support unit  11  has a circular cross-sectional shape in XY directions, this should not be understood as a limitation. For example, the shaft portion  12  may be formed in the shape of a rectangular prism or the like with a polygonal, such as rectangular, cross-sectional shape. The shape of the sheet hole  41 U through which the shaft portion  12  is passed is not limited to circular but may instead be polygonal. 
       LIST OF REFERENCE SIGNS 
       [0000]    
       
           11  support unit 
           12  shaft portion 
           12 T shaft portion&#39;s tip end 
           12 S shaft portion&#39;s side face 
           12 B shaft portion&#39;s base end 
           13  base portion 
           13 U base portion&#39;s top face 
           13 S base portion&#39;s side face 
           13 B base portion&#39;s bottom face 
           14  unit anchor portion 
           15  brim portion (first supporting portion, second supporting portion) 
           16  projection portion (first supporting portion, second supporting portion) 
           21  lamp clip 
           22  clip portion 
           23  pillar portion 
           24  clip anchor portion 
           41  reflective sheet 
           41 R reflective sheet&#39;s reflective surface 
           41 V reflective sheet&#39;s non-reflective surface 
           41 N half-cut line 
           41 U support unit sheet hole 
           41 L lamp clip sheet hole 
           42  optical sheet stack 
           43  diffuser sheet 
           51  fluorescent lamp (linear light source, light source) 
           53  backlight chassis (chassis) 
           53 U support unit chassis hole 
           53 L lamp clip chassis hole 
           55  LED (linear light source, light source) 
           69  backlight unit (illuminating device) 
           79  liquid crystal display panel (display panel) 
           89  liquid crystal display device (display device)