Abstract:
An illumination device has at least one fluorescent tube, a lower frame supporting the fluorescent tube, a light diffusion plate which opposes the lower frame with the fluorescent tube being interposed therebetween for forward diffusion of output light of the fluorescent tube, a reflection sheet disposed along the fluorescent tube side of the lower frame for reflecting the fluorescent light toward the light diffuser plate, and an upside reflector covering an electrode of the fluorescent tube for reflecting the light toward the light diffuser. When letting a direction along a length of the fluorescent tube be a horizontal direction, a distance between the fluorescent tube and the reflection sheet at at least one of nearby portions of right and left ends of the illuminator is greater than such distance at a central portion thereof. A liquid crystal display (LCD) apparatus using the illuminator is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to an illumination device using one or more fluorescent tubes, and also relates to a liquid crystal display (LCD) apparatus using the illumination device. 
         [0002]      FIG. 12A  shows a front view of one prior known LCD television (TV) receiver  101 , and  FIG. 12B  is a back view showing main parts of the LCD TV shown in  FIG. 12A  on a backface thereof. 
         [0003]    In addition,  FIG. 13A  is an enlarged cross-sectional view of the LCD TV as taken along a line E-E of  FIG. 12A , and  FIG. 13B  is its enlarged cross-sectional view taken along a line F-F of  FIG. 12A . 
         [0004]    As shown in  FIG. 12A , the prior art LCD TV  101  has a display screen G for visual display of video images thereon. When displaying a video image on this display screen G, light is emitted for transmission to an LCD panel  102  (see  FIGS. 13A and 13B ) from its backside, and the panel is voltage-controlled in accordance with the video image, resulting in the image being displayed on the screen. 
         [0005]    As shown in  FIGS. 13A and 13B , this LCD TV  101  is generally made up of the LCD panel  102  and an illumination device  101 S which is placed behind the LCD panel  102  for supplying light to the LCD panel  102  from its backside (rear surface side of drawing sheet of  FIG. 12A ). The LCD panel  102  is rigidly attached to the illumination device  101 S by an upper frame  103 . 
         [0006]    The LCD panel  102  changes the transmissivity of the light that passes through a liquid crystal (LC) layer in a way corresponding to respective pixels constituting the image to be displayed, thereby controlling the transmission and non-transmission of the light from the illumination device  101 S for displaying the image on the display screen G (see  FIG. 12A ) by a transmission degree of the light of a color filter. 
         [0007]      FIG. 14  is an exploded view of the LCD TV  101  shown in  FIG. 12A  when looking at from its front side (top face side of drawing sheet of  FIG. 12A ). 
         [0008]    As shown in  FIG. 14 , the illumination device  101 S (see  FIGS. 13A and 13B ) has a plurality of fluorescent tubes  104  for use as a light source unit, an inverter  105  for driving the fluorescent tubes  104 , a lower frame  106  for disposing the fluorescent tubes  104 , a reflection sheet  106   h  which is disposed along a front face of the lower frame  106  for reflecting light rays of the fluorescent tubes  104  toward the LCD panel  102  side, a light diffusion plate  107  for diffusing the light as output from the fluorescent tubes  104 , an optical sheet  108  for control of an angular distribution or the like of the light that enters the LCD panel  102 , an intermediate mold frame  109  which fastens the optical sheet  108  and light diffusion plate  107  to the lower frame  106  and which mounts thereon the LCD panel  102 , and an upside mold  110  which functions as a light shield wall of right and left end portions of the display screen. 
         [0009]    Note here that  FIG. 14  shows main parts or components only, and there are many other members. 
         [0010]    As shown in  FIG. 12B , several structural members are disposed on the non-display plane side of the LCD TV  101 , and the members include circuit components, such as a timing controller Tcon, the inverter  105 , a power supply unit  111  and others. 
         [0011]    Additionally, prior art bulletins of the invention in relation to this application include JP-A-2007-59406 (in its paragraphs [0022] to [0024]) and JP-A-2007-18423. 
         [0012]    JP-A-2007-59406 discloses therein a display apparatus of the type using an external electrode fluorescent lamp as a back-light thereof. JP-A-2007-18423 teaches a display device which uses an internal electrode fluorescent lamp as its backlight: in  FIG. 8  of this Japanese patent bulletin, a similar arrangement to that shown in  FIG. 13A  of the present application is depicted. 
       SUMMARY OF THE INVENTION 
       [0013]    Incidentally,  FIG. 13A  shows an illumination device  103  which is equivalent in structure to a thickness-reduced or “thinned” version of the prior art illumination device, i.e., an arrangement with a light diffusion distance being shortened. 
         [0014]    As indicated by arrows in  FIG. 13A , output light emitted from the fluorescent tubes  104  enters the reflection sheet  106   h  and light diffusion plate  107 , and undergoes diffused reflection; further, such light enters the reflection sheet  106   h  or the light diffusion plate  107 . By repeating this procedure, the light expands within a light diffusion space K which is surrounded by the light diffusion plate  107 , upside mold  110  and reflection sheet  106   h.    
         [0015]    It should be noted that the diffused reflection denotes that incident light from a given direction is reflected at every possible angle. On the contrary, regular reflection refers to a phenomenon that incoming light at an angle of incidence is reflected at a specific angle which is the same as the angle of incidence. 
         [0016]    As both the reflection sheet  106   h  and the light diffusion plate  107  have diffused reflection planes, each of them undergoes diffused reflection. In particular, the light diffusion plate  107  functions to cause the incident light to undergo diffused reflection to return to inside of the light diffusion space K while at the same time permitting a certain amount of light to pass therethrough to the LCD panel  102  side. 
         [0017]    In  FIG. 13A , a route along which the light that emitted from a point “A” of the fluorescent tube  104  travels from a point B of the light diffusion plate up to the surface of LCD panel  102  is indicated by arrows, wherein the width or “fatness” of an arrow corresponds to the intensity of the light. 
         [0018]    As previously stated, light undergoes diffused reflection, so that this is not simply representable by such a single arrow. However,  FIG. 13A  shows, for purposes of convenience in illustration herein, a light ray that is emitted at an angle of 45 degrees chosen or “picked up” from those light rays that have emitted from the point A and are incident on the reflection sheet  106   h  at the angle of 45 degrees and then undergo the diffused reflection. Similarly, since the light as reflected from the reflection sheet  106   h  at the angle of 45 degrees is incident on the light diffusion plate  107  at the angle of 45 degrees, a light ray which is reflected at 45 degrees is picked up from those rays which are diffused and reflected at the light diffusion plate  107 . 
         [0019]    As the incoming light from a certain direction is reflected to all possible directions, reflection light at a specific angle decreases in light intensity with respect to its corresponding incident light (i.e., arrow becomes slimmer). In other words, the thinner the illumination device  101 S, the greater the frequency of reflection: the more the frequency of reflection, the less the light intensity. 
         [0020]    In  FIG. 13A , five reflections undergo repeatedly for traveling from the point A to reach the point B. As previously stated, the incoming light from the center side becomes weaker at the right and left end portions including the point B; thus, there is a problem that it becomes darker. 
         [0021]    When the illumination device  101 S gets darker at its ends, this poses a problem that the right and left end portions Gr, Gl (see  FIG. 12A ) of the display screen G for displaying video images on the LCD panel  102  become darker. 
         [0022]    One known approach to solving this problem is to enlarge the illumination device  101 S for increasing its lateral size to thereby exclude such dark portions in the right and left part regions of the illumination device  101 S from the display screen G. Unfortunately, this approach is faced with a problem that right and left bezel parts  101   g,    101   g  (see  FIG. 12A ) become larger, resulting in significant failure of design properties and also in degradation of commodity values. 
         [0023]    Similarly,  FIG. 13B  shows a route along which the output light that emitted from a point “C” of the fluorescent tube  104  travels from a point D of the light diffusion plate to the surface of LCD panel  102  is indicated by arrows, wherein the width of each arrow corresponds to the intensity of light. 
         [0024]    The thinner the illumination device  101 S, the greater the frequency of reflection at the reflection sheet  106   h  and light diffusion plate  107 : the more the reflection frequency, the less the light intensity. In  FIG. 13B , five reflections are repeated for traveling from the point C to the point D. This causes a problem that the point D-containing upper end and lower end become darker because of the fact that the incoming light from the center side becomes weaker. 
         [0025]    When the illumination device  101 S gets darker at these ends, this poses a problem that regions of the upper and lower end portions Gv, Gs (see  FIG. 12A ) of the display screen G for displaying video images on the LCD panel  102  become darker. 
         [0026]    As stated above, in the case of reducing the body thickness of the illumination device  101 S of the LCD TV  101 , there is a technical problem to be solved: the right and left ends Gr, Gl and upper and lower ends Gv, Gs of the display screen G, which is an image display area, decrease in brightness. 
         [0027]    This invention has been made in view of the above-stated background, and its object is to provide an illumination device capable of improving the brightness or luminance of the upper and lower end portions and/or the right and left end part regions without having to increase the width of bezel part around the display screen, and also provide a display apparatus using the illumination device. 
         [0028]    To attain the foregoing object, in accordance with a first aspect of this invention, an illumination device is provided, which includes at least one fluorescent tube, a lower frame member supporting the fluorescent tube, a light diffusion plate disposed to oppose the lower frame member with the fluorescent tube being interposed therebetween for diffusing light of the fluorescent tube toward an anterior object to be illuminated, a reflection sheet member disposed along the fluorescent tube side of the lower frame member for reflecting the light of the fluorescent tube toward the light diffusion plate, and an upside reflection member for covering an electrode of the fluorescent tube and for reflecting the light of the fluorescent tube to the light diffusion plate, wherein when letting a lengthwise direction of the fluorescent tube be a transverse direction, a distance between the fluorescent tube and the reflection sheet member at at least one of portions adjacent to the right and left ends of the illumination device is greater than such distance at a central portion thereof. 
         [0029]    In accordance with a second aspect of this invention, an illumination device includes at least one fluorescent tube, a lower frame member supporting the fluorescent tube, a light diffusion plate disposed to oppose the lower frame member with the fluorescent tube being interposed therebetween for diffusing light of the fluorescent tube toward an anterior object to be illuminated, a reflection sheet member disposed along the fluorescent tube side of the lower frame member for reflecting the light of the fluorescent tube toward the light diffusion plate, and an upside reflection member for covering an electrode of the fluorescent tube and for reflecting the light of the fluorescent tube to the light diffusion plate, wherein when letting a direction along an extending surface direction of the reflection sheet member and perpendicular to a lengthwise direction of the fluorescent tube be an up-and-down direction, a distance between the fluorescent tube and the reflection sheet member at at least one of portions adjacent to the upper and lower ends of the illumination device is greater than the distance at a central portion thereof. 
         [0030]    In accordance with a third aspect of the invention, an illumination device has at least one fluorescent tube, a lower frame member supporting the fluorescent tube, a light diffusion plate disposed to oppose the lower frame member with the fluorescent tube being interposed therebetween for diffusing light of the fluorescent tube toward an anterior object to be illuminated, a reflection sheet member disposed along the fluorescent tube side of the lower frame member for reflecting the light of the fluorescent tube toward the light diffusion plate, and an upside reflection member for covering an electrode of the fluorescent tube and for reflecting the light of the fluorescent tube to the light diffusion plate, wherein when letting a lengthwise direction of the fluorescent tube be a transverse direction and letting a direction along an extending surface direction of the reflection sheet member and perpendicular to the lengthwise direction of the fluorescent tube be an up-and-down direction, a distance between the fluorescent tube and the reflection sheet member at any one of portions adjacent to the upper and lower ends and the right and left ends of the illumination device is greater than the distance at a central portion thereof. 
         [0031]    In accordance with a fourth aspect of this invention, a display apparatus is provided, which is arranged to use any one of the above-stated illumination devices incorporating the principles of the invention. 
         [0032]    According to this invention, it is possible to make brighter the right and left end portions or the upper and lower ends of the illumination device without increasing the width of the bezel part around the display screen. 
         [0033]    Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1A  is a diagram showing a front view of a liquid crystal display (LCD) television (TV) receiver in accordance with a first embodiment of this invention,  FIG. 1B  is an enlarged cross-sectional view of the LCD TV as taken along a line G-G of  FIG. 1A , and  FIG. 1C  is an enlarged cross-sectional view of the LCD TV as taken along a line H-H of  FIG. 1A . 
           [0035]      FIG. 2  is an exploded view of the LCD TV shown in  FIG. 1A  when looking at from its front side. 
           [0036]      FIG. 3  is a back view for showing main part of the LCD TV shown in  FIG. 1A  on a back face thereof. 
           [0037]      FIG. 4A  is a diagram showing a front view of an LCD TV in accordance with a second embodiment of the invention,  FIG. 4B  is an enlarged cross-sectional view of the LCD TV as taken along a line I-I of  FIG. 4A , and  FIG. 4C  is an enlarged cross-sectional view of the LCD TV taken along a line J-J of  FIG. 4A . 
           [0038]      FIG. 5  is a back view showing main part of the LCD TV of the second embodiment shown in  FIG. 4A  on its back face. 
           [0039]      FIG. 6A  is a front view of an LCD TV in accordance with a third embodiment of the invention,  FIG. 6B  is an enlarged cross-sectional view of the LCD TV as taken along a line K-K of  FIG. 6A , and  FIG. 6C  is an enlarged cross-sectional view of the LCD TV taken along a line L-L of  FIG. 6A . 
           [0040]      FIG. 7  is a back view showing main part of the LCD TV shown in  FIG. 6A  on its backface. 
           [0041]      FIG. 8A  is a front view of an LCD TV in accordance with a fourth embodiment of the invention,  FIG. 8B  is an enlarged cross-sectional view of the LCD TV as taken along a line M-M of  FIG. 8A , and  FIG. 8C  is an enlarged cross-sectional view of the LCD TV taken along a line N-N of  FIG. 8A . 
           [0042]      FIG. 9  is a back view showing main part of the LCD TV of the fourth embodiment shown in  FIG. 8A  on its backface. 
           [0043]      FIG. 10  is an enlarged cross-sectional illustration diagram along a line G-G of  FIG. 1A  while showing a relationship of the brightness of light versus position in the lateral direction of a display screen of an illumination device. 
           [0044]      FIG. 11A  is a diagram showing regions W 1  and W 2  with a print pattern being formed on a light diffusion plate or an optical sheet in the display screen shown in  FIG. 1A , and  FIG. 11B  is a diagram showing the print pattern of an “O” part of  FIG. 11A  and also showing the print pattern at “P” part of  FIG. 11A . 
           [0045]      FIG. 12A  is a front view of a prior known LCD TV, and  FIG. 12B  is a back view showing main part of the LCD TV shown in  FIG. 12A  on its backface. 
           [0046]      FIG. 13A  is an enlarged cross-sectional view of the prior art LCD TV as taken along a line E-E of  FIG. 12A , and  FIG. 13B  is an enlarged cross-sectional view of the LCD TV taken along a line F-F of  FIG. 12A . 
           [0047]      FIG. 14  is an exploded view of the prior art LCD TV shown in  FIG. 12A  when looking at from its front side. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0048]    Embodiments of this invention will be described with reference to the accompanying drawings below. 
       First Embodiment  
       [0049]    As shown in  FIG. 1A , a liquid crystal display (LCD) television (TV) receiver apparatus  1  in accordance with a first embodiment of this invention is arranged to have a display screen G, on which video images are to be visually displayed. When displaying images on this display screen G, light is emitted to pass through an LCD panel from its backside for displaying video images thereon. The LCD panel has a layer of liquid crystal (LC) material, which is voltage-controlled in accordance with a video image being displayed, and a color filter (not shown) having pixels. 
         [0050]    Note here that  FIG. 1A  is a diagram showing a front view of the LCD TV  1 ,  FIG. 1B  is an enlarged cross-sectional view of the LCD TV as taken along a line G-G of  FIG. 1A , and  FIG. 1C  is an enlarged cross-sectional view of the LCD TV as taken along a line H-H of  FIG. 1A .  FIG. 2  is an exploded view of the LCD TV  1  shown in  FIG. 1A  when looking at from its front side (top surface side of drawing sheet of  FIG. 1A ). 
       &lt;Arrangement of LCD TV Receiver  1 &gt; 
       [0051]    As shown in  FIGS. 1B and 1C , the LCD TV receiver  1  is generally made up of an LCD panel  2  and an illumination device  1 S, which is placed behind the LCD panel  2  for supplying light to the LCD panel  2  from its backside (rear surface of the drawing sheet of  FIG. 1A ). The LCD panel  2  is rigidly attached to an upper frame  3  (see  FIG. 2 ). 
         [0052]    As shown in  FIG. 2 , the upper frame  3  has a flat rectangular box-like shape having an opening at a part corresponding to the display screen G of the LCD panel  2 . 
         [0053]    The LCD panel  2  is such that a voltage is applied to the LC layer in a way corresponding to respective pixels constituting a video image to be displayed, for controlling transmission and non-transmission of the incoming light from backside of the illumination device  1 S to thereby visually display the video image on the display screen G (see  FIG. 1A ) by a transmission degree of the light at each pixel of the color filter. 
       &lt;Arrangement of Illumination Device  1 S in LCD TV  1 &gt; 
       [0054]    As shown in  FIGS. 1B and 1C , the illumination device  1 S which supplies light to the LCD panel  2  from its backside (rear face of the drawing sheet of  FIG. 1A ) is arranged to have a plurality of fluorescent tubes  4  for use as a light source unit, an inverter  5  which drives the fluorescent tubes  4 , a lower frame  6  which disposes and holds the fluorescent tubes  4 , a reflection sheet  6   h  which is disposed along a front face of the lower frame  6  for permitting reflection of light rays of the fluorescent tubes  4  toward the LCD panel  2  side, a light diffusion plate  7  for diffusing the light that is emitted from the fluorescent tubes  4  toward the LCD panel  2 , an optical sheet  8  (generally, more than two optical sheets  8  are present) for control of angular distribution or the like of the light incident on the LCD panel  2 , an intermediate frame  9  (see  FIG. 2 ) which is made of a rectangular frame-like resin material for mounting the LCD panel  2  thereon while pressing the optical sheet  8  and light diffusion plate  7  to the lower frame  6 , and an upside mold  9   a  which acts as a light shield wall of the right and left end portions. 
         [0055]    The light diffusion plate  7  is configured so that refractivity-different particles are contained therein for causing diffusion or dispersion of the light from the fluorescent tubes  4  which are for use as the light source, thereby preventing an occurrence of brightness irregularities of the illumination device  1 S. Note here that in some cases, a pattern which will be described later is formed on a surface of the light diffusion plate  7  for further prevention of such brightness irregularities. 
         [0056]    As shown in  FIGS. 1B-1C , the lower frame  6  is a reinforcement member which supports the LCD panel  2 , illumination device  1 S, fluorescent tubes  4  and others. For example, this is manufactured by using a steel plate with a thickness of about 1 mm. As better shown in  FIG. 2 , this plate is formed to have a low-profile rectangular box-like shape which covers the back surface side of the illumination device  1 S and which has an opening in one face on the LCD panel  2  side. 
         [0057]    As shown in  FIG. 2 , at both side portions on the right and left sides of this lower frame  6 , concave portions  6   o   1 ,  6   o   2  (see  FIGS. 1B-1C ) are formed by known press/emboss-machining techniques. Each concave portion is depressed toward the backside (rear face direction of the paper of  FIG. 1A ) and extends in an up-and-down direction (up-down direction of the paper of  FIG. 1A ) in such a manner as to allow the light from the fluorescent tubes  4  for use as the light source to reflect toward a reflection sheet  6   h  to be later described, which is within the concave portion  6   o   1 ,  6   o   2 , and reach the right and left ends of the display screen G shown in  FIG. 1A . 
         [0058]    As shown in  FIGS. 1B-1C , the reflection sheet  6   h  which is disposed on the fluorescent tube  4  side in close proximity to the lower frame  6  is fabricated by use of a sheet of white paper having a thickness of 0.3 mm and reflectivity of 99% or greater for achieving good reflection of the light from the fluorescent tubes  4 , for example. This reflection sheet  6   h  is formed to extend along the shape of the lower frame  6  and has concave portions  6   h   1 ,  6   h   2  along the concave portions  6   o   1 ,  6   o   2  of the lower frame  6 . 
         [0059]    As shown in  FIGS. 1B-1C  and  2 , the upside mold  9   a  is molded by using a white-colored resin material which is high in reflectivity and is arranged such that electrodes  4   a,    4   a  at the both ends of a fluorescent tube  4  where no output light rays is emitted are covered with the white resin, and light from the fluorescent tube  4  is reflected at a surface of the white resin having a shape of being slanted backward, i.e., toward the anti-LCD panel  2  side as it goes to the center while the electrodes  4   a,    4   a  are exposed to the LCD panel  2  side, thereby generation of dark brightness unevenness is prevented. 
         [0060]    Note here that  FIG. 2  depicts main constituent parts or components only, wherein various other members exist therein. 
       &lt;Traveling of Backlight Within Illumination Device  1 S&gt; 
       [0061]    As shown in  FIGS. 1B-1C , the light that was emitted from the fluorescent tubes  4  for use as the light source enters the reflection sheet  6   h  and the light diffusion plate  7  and undergoes diffused reflection and thereafter enters either the reflection sheet  6   h  or the light diffusion plate  7 . By repeating this procedure, the light expands within a light diffusion space which is surrounded by the light diffusion plate  7 , upside mold  9   a  and reflection sheet  6   h.    
         [0062]    As both the reflection sheet  6   h  and the light diffusion plate  7  are diffused reflection planes, diffused reflection occurs. The light diffusion plate  7  functions to permit the incident light to experience diffused reflection and to return it to the above-noted light diffusion space while simultaneously allowing a certain amount of light to pass through for output to the LCD panel  2  side. 
         [0063]    In  FIG. 1B , a route along which the light emitted from the fluorescent tubes  4  and output from a point A 1  is traveling from a point B 1  of the light diffusion plate  7  to the surface of the LCD panel  2  is indicated by arrows, wherein the width of an arrow corresponds to the intensity of such light. 
         [0064]    In  FIG. 1C , a route along which the light that was emitted from the fluorescent tubes  4  and output from a point C 1  is traveling from a point D 1  of the light diffusion plate  7  to the surface of LCD panel  2  is indicated by arrows, wherein the width of each arrow corresponds to the intensity of the light. 
         [0065]    As previously stated, light undergoes diffused reflection so that this is not simply representable by such a single arrow. However,  FIG. 1B  or  1 C shows, for purposes of convenience in illustration, a light ray that outputs at an angle of 45 degrees, which is “picked up” from those light rays that have output from the point A 1  or C 1  and are incident on the reflection sheet  6   h  at the angle of 45 degrees and then undergo the diffused reflection. 
         [0066]    Similarly, since the light as output from the reflection sheet  6   h  at the angle of 45 degrees enters the light diffusion plate  7  at the angle of 45 degrees, a light ray which is reflected at 45 degrees is picked up from those rays which are diffused and reflected at the light diffusion plate  7 . 
         [0067]    In  FIGS. 1B-1C , since the light that entered from a certain direction is reflected to all possible directions, reflected light at a specific angle decreases in light intensity as compared to the incident light (its corresponding arrow becomes slimmer). In short, the more the frequency of reflections, the less the light intensity. 
         [0068]    In  FIG. 1B , only three reflections are needed for light to travel from the point A 1  to the point B 1 . Similarly, in  FIG. 1C , only three reflections are needed for light to reach the point D 1  from the point C 1 . 
         [0069]    This is owing to the arrangement which follows: as shown in  FIG. 2 , the concave portions  6   o   1 ,  6   o   2  are formed in the lower frame  6  by press/emboss machining techniques to have the shape of being depressed backward, i.e., toward the non-display plane side; the concave portions  6   h   1 ,  6   h   2  are formed in the reflection sheet  6   h  so that each extends along the concave portions  6   o   1 ,  6   o   2 ; as shown in  FIGS. 1B-1C , the distance between the fluorescent tubes  4  and the reflection sheet  6   h  in the right and left part regions is increased to thereby reduce to three times the frequency of reflection of the light traveling from the point A 1  to the point B 1  shown in  FIG. 1B , while at the same time, to reduce to three times the frequency of reflection of the light traveling from the point C 1  to the point D 1  shown in  FIG. 1C , thereby enabling light to readily reach the right and left ends of the light diffusion plate  7  from the center side. 
         [0070]    With this arrangement, the problem that the right and left end part regions of the illumination device  1 S—i.e., the right and left end part regions of the display screen G (see FIG.  1 A)—are dark is solved without employing a design of extending the length of the fluorescent tubes  4  and increasing the width (concealing dark portions) of the right and left bezel parts  3   h,    3   m  of the upper frame  3  shown in  FIG. 1A  in order to cover the electrodes  4   a,    4   a  of such lengthened fluorescent tubes  4 . 
         [0071]      FIG. 3  is a back view showing the main part of the LCD TV  1  shown in  FIG. 1A . 
         [0072]    As shown in  FIGS. 1B-1C  and  3 , several constituent components are disposed on the non-display plane side of the LCD TV  1 , which include electrical circuit members, such as a timing controller Tcon which drives and controls the LCD panel  2 , the inverter  5  for driving the fluorescent tubes  4 , and a power supply unit E or the like, or other structural members, wherein these components are laid out on backside of the lower frame  6 , that is, in a region between the concave portions  6   o   1 ,  6   o   2  each having the shape of extending to the non-display plane side, i.e., in a surface area of the lower frame  6  which has no pressed/embossed portions. 
         [0073]    The press/emboss-machining depth of the concave portions  6   o   1 ,  6   o   2  of the lower frame  6  is specifically set to a value that is less than or equal to the thickness of these structural members, such as the inverter  5  and others, whereby it is possible to keep thin the entire body thickness of the LCD TV  1  while at the same time avoiding the darkness of the right and left end portions of the display screen G shown in  FIG. 1A , i.e., the right and left ends of the illumination device  1 S. 
         [0074]    Note here that if the size of extension of the concave portion  6   o   1 ,  6   o   2  of the lower frame  6  toward the non-display plane side is greater than thickness sizes of circuit members, such as the timing controller Tcon, the inverter  5  and the power supply E or other structural members, it is possible to determine the thickness size of the LCD TV  1  by the size of the concave portion  6   o   1 ,  6   o   2  of lower frame  6  extending to the non-display plane side. 
         [0075]    Adversely, if the size of extension of the concave portion  6   o   1 ,  6   o   2  of the lower frame  6  toward the non-display plane side is less than the thickness sizes of the circuit members, such as the timing controller Tcon, the inverter  5  and the power supply E, or other structural members, it is possible to define the thickness size of the LCD TV  1  by the thickness sizes of the circuit members, such as the timing controller Tcon, inverter  5  and power supply E, or the other structural members. 
         [0076]    Note that although in the first embodiment there is exemplified one specific case where the concave portions  6   o   1 ,  6   o   2  are formed by press/emboss machining methods at the right and left end portions of the lower frame  6 , it is also possible to form such concave portion only at at least either one of the right and left ends—for example, only the concave portion  6   o   1  is formed or, alternatively, only the concave portion  6   o   2  is formed. 
         [0077]    With this arrangement also, similar functions and effects to those of the above-stated first embodiment are achievable. 
         [0078]    Also note that although in the first embodiment the explanation was given for the example case where the right and left concave portions  6   o   1 ,  6   o   2  of the lower frame  6  are integrally formed in the lower frame  6  by press/emboss machining techniques, it is also possible to form a similar structure by a process having the steps of forming openings at portions corresponding to the right and left concave portions  6   o   1 ,  6   o   2  of lower frame  6 , forming concave portions  6   o   1 ,  6   o   2  by separate parts, and fastening them to the openings by welding or bolt-screwing methods in such a way as to block up these openings. 
       Second Embodiment  
       [0079]      FIG. 4A  is a diagram showing a front view of an LCD TV receiver  21  in accordance with a second embodiment of the invention,  FIG. 4B  is an enlarged cross-sectional view of the LCD TV as taken along a line I-I of  FIG. 4A , and  FIG. 4C  is an enlarged cross-sectional view of the LCD TV taken along a line J-J of  FIG. 4A . 
         [0080]    The LCD TV  21  which is the second embodiment (see  FIG. 4A ) is the one that has upper and lower concave portions  26   o   3 ,  26   o   4  (see  FIGS. 4B-4C ) which are formed at the upper and lower end portions of a lower frame  26  in place of the press/emboss-machined right and left concave portions  6   o   1 ,  6   o   2  in the lower frame  6  of the first embodiment, thereby avoiding the darkness of the upper and lower ends of an illumination device  21 S. 
         [0081]    This embodiment is similar to the first embodiment in arrangements other than the above-noted one, so, similar constituent elements marked with same reference numerals are indicated by numerals, adding 2 to each as a most significant digit, and similar elements marked with the same reference characters are indicated by such same characters, and their detailed explanations are omitted here. 
         [0082]    As shown in  FIG. 4B , a sidewall part  26   a   1  which extends toward the backside in the form of a plane is formed at the upper end portion of the lower frame  26 . In the case of disposing a reflection sheet  26   h  along this sidewall part  26   a   1 , light directed to the upper end of the illumination device  21 S becomes deficient, resulting in generation of a dark portion(s). 
         [0083]    To avoid this, as shown in  FIG. 4B , the reflection sheet  26   h  is formed to have a slanted or “sloped” portion  26   h   2  which is inclined toward the backside, i.e., to the anti-LCD panel  22  side, as it goes from its upper edge to the center side of the lower frame  26  in the form of being spaced apart from the sidewall part  26   a   1  of lower frame  26 . By forcing the light that is emitted from fluorescent tubes  24 ,  24 , . . . in a central area of the illumination device  21 S to be reflected from this sloped portion  26   h   2  to the upper end side, it is possible to increase the brightness of the illumination device  21 S at its upper end and prevent creation of dark portions, resulting in achievement of uniformization of light rays of the illumination device  21 S. 
         [0084]    Similarly, as shown in  FIG. 4C , a sidewall part  26   a   2  is formed at the lower end of the lower frame  26 , which extends planarly toward the backside. In case the reflection sheet  26   h  is provided along this sidewall part  26   a   2 , the light of the illumination device  21 S which approaches the lower end becomes deficient, resulting in occurrence of dark portions. 
         [0085]    To avoid this, as shown in  FIG. 4C , the reflection sheet  26   h  is formed to have a slanted portion  26   h   2  which is inclined toward the backside, i.e., to the anti-LCD panel  22  side, as it goes from its lower edge to the center side of the lower frame  26  in the form of being spaced apart from the sidewall part  26   a   2  of the lower frame  26 . By forcing the light that is emitted from the fluorescent tubes  24 ,  24 , . . . in the central area of the illumination device  21 S to be reflected at this sloped portion  26   h   2  to the lower end side, it is possible to increase the brightness of the illumination device  21 S at its lower end and prevent occurrence of dark portions, resulting in achievement of the uniformization of the light of the illumination device  21 S. 
         [0086]    As shown in  FIGS. 4B-4C , the light that emitted from the fluorescent tubes  24  enters the reflection sheet  26   h  and a light diffusion plate  27  and undergoes diffused reflection, and then enters either the reflection sheet  26   h  or the light diffusion plate  27 . By repeating this procedure, the light expands within a light diffusion space, which is surrounded by the light diffusion plate  27 , an upside mold  29   a  and the reflection sheet  26   h.    
         [0087]    As both the reflection sheet  26   h  and the light diffusion plate  27  are diffused reflection planes, diffused reflection occurs. The light diffusion plate  27  serves to cause incident light to undergo diffused reflection and to return it to the above-noted light diffusion space, and at the same time allows a certain amount of light to pass through for output to the LCD panel  22  side. 
         [0088]    In  FIG. 4B , a route along which the light that was emitted from the fluorescent tubes  24  for outputting from a point A 2  is traveling from a point B 2  of the light diffusion plate  27  toward the surface of the LCD panel  22  is indicated by arrows, wherein the width of an arrow corresponds to the intensity of such light. 
         [0089]    In  FIG. 4C , a route along which the light that was emitted from the fluorescent tubes  24  for outputting from a point C 2  is traveling from a point D 2  of the light diffusion plate  27  toward the surface of LCD panel  22  is indicated by arrows, wherein the width of each arrow corresponds to the intensity of the light. 
         [0090]    As previously stated, light undergoes diffused reflection so that this is not simply representable by such a single arrow, However,  FIG. 4B  or  4 C shows, for purposes of convenience in illustration, a light ray that outputs at an angle of 45 degrees, which is “picked up” from those light rays that have output from the point A 2  or C 2  and are incident on the reflection sheet  26   h  at the angle of 45 degrees and then undergo the diffused reflection. Similarly, since the light as output from the reflection sheet  26   h  at the angle of 45 degrees behaves to enter the light diffusion plate  27  at the angle of 45 degrees, a light ray which is reflected at 45 degrees is picked up from those rays which are diffused and reflected at the light diffusion plate  27 . 
         [0091]    In  FIGS. 4B-4C , the incident light that enters from a certain direction is reflected to all possible directions; so, reflected light at a specific angle decreases in light intensity as compared to the incident light (its arrow becomes slimmer). In brief, the more the frequency of reflection, the less the light intensity. 
         [0092]    In  FIG. 4B , only three reflections are needed for light to travel from the point A 2  to the point B 2 . Similarly, in  FIG. 4C , only three reflections are needed for the light to reach the point D 2  from the point C 2 . 
         [0093]    This is owing to the arrangement which follows: as shown in  FIGS. 4B-4C , the concave portions  26   o   3 ,  26   o   4  are formed by press/emboss machining methods at the upper and lower ends of the lower frame  26 , respectively, wherein each concave portion is depressed to the backside, i.e., the non-display plane side; a concave portion  26   h   3  is formed in the reflection sheet  26   h  so that it extends along the concave portion  26   o   3  of the upper end of the lower frame  26 ; and, a concave portion  26   h   4  is formed, which is along the concave portion  26   o   4  of the lower end of lower frame  26 . 
         [0094]    By increasing the distance between the fluorescent tubes  24  and the lower frame  26  in the upper and lower end part regions in this way, the frequency of reflection of the light that travels from the point A 2  to the point B 2  shown in  FIG. 4B  is reduced to three times and, simultaneously, the frequency of reflection of the light that progresses from the point C 2  to the point D 2  shown in  FIG. 4C  is reduced to three times, thereby enabling the light to readily reach the upper and lower ends of the light diffusion plate  27  from the center side. 
         [0095]    With this arrangement, the problem that the upper and lower end regions of the illumination device  21 S are dark is avoidable without increasing the fluorescent tubes  24  in number and increasing the width sizes (concealing dark portions) of an upper bezel part  23   u  and a lower bezel part  23   s  of the upper frame  23 , which are at upper and lower positions of the display screen G shown in  FIG. 4A . 
         [0096]      FIG. 5  is a back view showing main part of the LCD TV  21  shown in  FIG. 4A . 
         [0097]    As shown in  FIGS. 4B-4C  and  5 , several constituent components are disposed on the non-display plane side of the LCD TV  21 , which include electrical circuit members, such as a timing controller Tcon, an inverter  25  and a power supply unit E or the like, or other structural members, wherein these components are situated on backside of the lower frame  26 , that is, in a region between the concave portions  26   o   3 ,  26   o   4  each having the shape of extending to the non-display plane side (top surface side of paper of  FIG. 5 ), i.e., in a surface area of the lower frame  26  which has no embossed portions. 
         [0098]    The embossing depth of the concave portions  26   o   3 ,  26   o   4  of the lower frame  26  is set to a value that is less than or equal to the thickness of these structural members, such as the inverter  25  and others, whereby it is possible to keep thin the entire body thickness of the LCD TV  21 . This avoids the darkness of the upper and lower ends of the display screen G shown in  FIG. 4A , i.e., the upper and lower ends of the illumination device  21 S. 
         [0099]    Note that it is possible to determine the thickness size of the LCD TV  21  by any longer one of the size of extension of the concave portion  26   o   3 ,  26   o   4  of the lower frame  26  toward the non-display plane side and the thickness size of electrical circuit members, such as the timing controller Tcon, inverter  25  and power supply E, or other structural members. 
         [0100]    Also note that although in the second embodiment there is indicated one exemplary case where the concave portions  26   o   3 ,  26   o   4  are formed by press/emboss machining methods at the upper and lower ends of the lower frame  26 , it is also possible to form such concave portion at at least either one of these upper and lower ends—for example, only the upper concave portion  26   o   3  (see  FIGS. 4B and 5 ) or, alternatively, only the lower concave portion  26   o   4  (see  FIGS. 4C and 5 ) is formed. 
         [0101]    With this arrangement also, similar functions and effects to those of the above-stated second embodiment are achieved. 
         [0102]    Also note that although in the second embodiment the explanation was given for the example case where the upper and lower concave portions  26   o   3 ,  26   o   4  of the lower frame  26  are integrally formed in the lower frame  26  by press/emboss machining techniques, it is also possible to form a similar structure by a process having the steps of forming openings at portions corresponding to the upper and lower concave portions  26   o   3 ,  26   o   4  of lower frame  26 , forming concave portions  26   o   3 ,  26   o   4  by separate parts, and rigidly attaching them to the openings by welding or bolt-screwing methods in such a way as to block up these openings. 
       Third Embodiment  
       [0103]      FIG. 6A  is a front view of an LCD TV receiver  31  in accordance with a third embodiment of the invention,  FIG. 6B  is an enlarged cross-sectional view of the LCD TV as taken along a line K-K of  FIG. 6A , and  FIG. 6C  is an enlarged cross-sectional view of the LCD TV taken along a line L-L of  FIG. 6A . 
         [0104]    The LCD TV  31  (see  FIG. 6A ) which is a display apparatus of the third embodiment is the one that forms, in a lower frame  36  of the third embodiment, the embossed concave portions  6   o   1 ,  6   o   2  (see  FIGS. 1A-1C  and  3 ) of the right and left ends of the lower frame  6  of the first embodiment and the embossed concave portions  26   o   3 ,  26   o   4  (see  FIGS. 4A-4C  and  5 ) of the upper and lower ends of the lower frame  26  of the second embodiment as embossed right and left concave portions  36   o   1 ,  36   o   2  and embossed upper and lower concave portions  36   o   3 ,  36   o   4  (see  FIGS. 6B and 6C ). 
         [0105]    The third embodiment is similar to the first and second embodiments in arrangements other than the above-noted arrangement, so, similar constituent elements with identical reference numerals are indicated by numerals, adding 3 to each as a most significant digit, and similar elements marked with the same reference characters are indicated by such same characters, with detailed explanations being omitted here. 
         [0106]    In  FIG. 6B , a route along which the light that was emitted from fluorescent tubes  34  for outputting from a point A 3  is output from a point B 3  of a light diffusion plate  37  toward the surface of an LCD panel  32  is indicated by arrows, wherein the width of an arrow corresponds to the intensity of such light. 
         [0107]    In  FIG. 6C , a route along which the light that was emitted from the fluorescent tubes  34  for outputting from a point C 3  is traveling from a point D 3  of the light diffusion plate  37  toward the surface of LCD panel  32  is indicated by arrows, wherein the width of each arrow corresponds to the intensity of the light. 
         [0108]    As previously stated, light undergoes diffused reflection so that this is not simply representable by such a single arrow. However,  FIG. 6B  or  6 C shows, for purposes of convenience in illustration, a light ray that outputs at an angle of 45 degrees, which is “picked up” from those light rays that have output from the point C 3  or C 4  and are incident on a reflection sheet  36   h  at the angle of 45 degrees and then undergo the diffused reflection. 
         [0109]    Similarly, since the light as output from the reflection sheet  36   h  at the angle of 45 degrees enters the light diffusion plate  37  at the angle of 45 degrees, a light ray which is reflected at 45 degrees is picked up from those rays which are diffused and reflected from the light diffusion plate  37 . 
         [0110]    In  FIG. 6B , only three reflections are needed for light to travel from the point A 3  to the point B 3 . Similarly, in  FIG. 6C , only three reflections are needed for the light to reach the point D 3  from the point C 3 . 
         [0111]    Regarding this feature, the case of the left end and upper end of the illumination device  31 S was explained. However, the right end and lower end of the illumination device  31 S are arranged in a similar way thereto. 
         [0112]      FIG. 7  is a back view showing main part of the LCD TV shown in  FIG. 6A  on its backface. 
         [0113]    As shown in  FIGS. 6B-6C  and  7 , the concave portions  36   o   1 ,  36   o   2 ,  36   o   3 ,  36   o   4  are formed by press/emboss machining methods at the right and left ends and the upper and lower ends of the lower frame  36 , respectively, wherein each has a shape of being depressed toward the backside, i.e., the non-display plane side, while forming in the reflection sheet  36   h  a set of concave portions  36   h   1 ,  36   h   2 ,  36   h   3 ,  36   h   4  which are along the concave portions  36   o   1 ,  36   o   2 ,  36   o   3 ,  36   o   4  to thereby increase the distance between fluorescent tubes  34  and the reflection sheet  36   h  in the right and left end part regions as shown in  FIGS. 6B-6C , thus enabling the light of the fluorescent tubes  34  on the center side to easily reach the right and left ends and the upper and lower ends of the light diffusion plate  37 . 
         [0114]    With this arrangement, the problem that the right and left end part regions of the illumination device  31 S are dark is solvable without employing a design of extending the length of the fluorescent tubes and increasing the width of the right and left bezel parts  33   h,    33   m  (see  FIG. 6A ) of an upper frame  33  in order to cover the electrode parts of the lengthened fluorescent tubes. 
         [0115]    In addition, the problem that the upper and lower end part regions of the illumination device  31 S are dark is avoidable without increasing the fluorescent tubes  34  in number and increase the width sizes of an upper bezel part  33   u  and a lower bezel part  33   s  of the upper frame  33  shown in  FIG. 6A . 
         [0116]    As shown in  FIGS. 6B-6C  and  7 , structural members are laid out on the non-display plane side of the LCD TV  31  in a surface area between the concave portions  36   o   1 ,  36   o   2 ,  36   o   3 ,  36   o   4  each having the shape of extending toward the backside of the lower frame  36 , i.e., the non-display plane side (top surface side of drawing sheet of  FIG. 7 ), that is, in a region of the lower frame  36  which is free from the emboss machining, wherein the structural members include electrical circuit components, such as a timing controller Tcon, an inverter  35 , a power supply E and others. 
         [0117]    By causing an emboss-machining depth of the concave portion  36   o   1 ,  36   o   2 ,  36   o   3 ,  36   o   4  of the lower frame  36  to be less than or equal to the thickness of these circuit components, such as the inverter  35  or else, it is possible to permit the LCD TV  31  to stay less in its entire thickness. It is also possible to avoid the darkness of the right and left ends and the upper and lower ends of display screen G, i.e., the darkness of the right and left ends and upper and lower ends of the illumination device  31 S. 
         [0118]    Note here that it is possible to determine the thickness size of the LCD TV  31  by any longer one of the size of the concave portion  36   o   1 ,  36   o   2 ,  36   o   3 ,  36   o   4  of the lower frame  36  extending to the backside, i.e., the non-display plane side, and the thickness size of the circuit members, such as the timing controller Tcon, inverter  35 , and power supply E, or other structural components. 
         [0119]    Also note that although in the third embodiment the explanation was given for the example case where the concave portions  36   o   1 ,  36   o   2 ,  36   o   3 ,  36   o   4  at the upper/lower and right/left ends of the lower frame  36  are integrally formed in the lower frame  36  by press/emboss machining techniques, it is also possible to form a similar structure by a method having the steps of forming a main body of the lower frame  36  and the concave portions  36   o   1 ,  36   o   2 ,  36   o   3 ,  36   o   4  by separate parts and fastening together the main body of lower frame  36  and the concave portions  36   o   1 ,  36   o   2 ,  36   o   3 ,  36   o   4  by welding or bolt-screwing techniques. 
       Fourth Embodiment  
       [0120]      FIG. 8A  is a front view of an LCD TV  41  of a fourth embodiment of the invention,  FIG. 8B  is an enlarged cross-sectional view of the LCD TV as taken along a line M-M of  FIG. 8A , and  FIG. 8C  is an enlarged cross-sectional view of the LCD TV taken along a line N-N of  FIG. 8A . 
         [0121]      FIG. 9  is a back view showing main part of the LCD TV  41  of the fourth embodiment shown in  FIG. 8A  on its backface. 
         [0122]    The LCD TV  41  (see  FIG. 8A ) which is a display apparatus of the fourth embodiment is arranged to define openings at the same locations as the emboss-machined concave portions  6   o   1 ,  6   o   2  at the right and left ends of the lower frame  6  in the first embodiment to thereby form openings  46   a   1 ,  46   a   2 . 
         [0123]    Then, a reflection sheet  46   h  is formed to have a protrusion portion  46   h   1  which is protruded from the opening  46   a   1  toward the backside, i.e., anti-LCD panel  42  side; simultaneously, a protrusion  46   h   2  that is protruded from the opening  46   a   2  to the backside is formed. 
         [0124]    Whereby, an arrangement is provided for expanding the distance between fluorescent tubes  44  and the reflection sheet  46   h,  i.e., the distance between the fluorescent tubes  44  and the protrusion  46   h   1  of reflection sheet  46   h  and also the distance between the fluorescent tubes  44  and the protrusion  46   h   2  of the reflection sheet  46   h.    
         [0125]    The fourth embodiment is similar to the first embodiment in arrangements other than the above-noted one, so, similar constituent elements with same reference numerals are indicated by numerals, adding  4  to each as a most significant digit, and similar elements marked with the same reference characters are indicated by such same characters, with their detailed explanations being omitted. 
         [0126]    Actually, in the case of defining the openings in the lower frame  46  to form the openings  46   a   1 ,  46   a   2 , electromagnetic waves are generated by discharge of the fluorescent tubes  44  to come and go through these openings  46   a   1 ,  46   a   2 . This will possibly affect operations of the circuit components mounted on the non-display plane shown in  FIG. 9 , such as the inverter  45 , timing controller Tcon, etc. 
         [0127]    One known remedy for this electromagnetic interference (EMI) is to overlay an electrical conductive sheet  41   d   1  on the backface side, i.e., rear side, of the protrusion  46   h   1  of the reflection sheet  46   h  for covering the opening  46   a   1  defined in the lower frame  46  as shown in  FIGS. 8B and 9  to thereby shield inside/outside spaces of the opening  46   a   1 . 
         [0128]    Similarly, as shown in  FIGS. 8C and 9 , a conductive sheet  41   d   2  is overlaid on the backface side, i.e., rear side, of the protrusion  46   h   2  of the reflection sheet  46   h  to cover the opening  46   a   2  defined in the lower frame  46  as shown in  FIGS. 8C and 9 , thereby shielding internal/external spaces of the opening  46   a   2 . 
         [0129]    By providing the conductive sheets  41   d   1 ,  41   d   2  in this way, it is possible to prevent or at least greatly suppress external leakage of electromagnetic waves due to the discharge of the fluorescent tubes  44 . This makes it possible to avoid bad influence on the circuit components, such as the inverter  45 , timing controller Tcon or the like. 
         [0130]    Except this arrangement, the fourth embodiment is similar in structure to the first embodiment, so that it offers similar functions and effects to those of the first embodiment. 
         [0131]    Note that although in the fourth embodiment the structural design for providing the above-stated arrangements at the right and left ends of the illumination device  41 S has been described, such arrangements may alternatively be provided at the upper and lower ends of the illumination device  41 S, rather than the right and left ends thereof. 
         [0132]    In addition, the arrangement may be provided at only one of the right and left ends or the upper and lower ends of the illumination device  41 S. Alternatively, the arrangements may be provided at the right/left ends and the upper/lower ends of the illumination device  41 S. 
         [0133]    In these cases also, the above-stated functions and effects are achievable in a similar way. 
       Fifth Embodiment  
       [0134]      FIG. 10  is an enlarged cross-sectional illustration along a line G-G of  FIG. 1A  for showing a relationship of the brightness of light versus position along the lateral direction (horizontal direction of the drawing sheet of  FIG. 1A ) of the display screen G in the illumination device  1 S. 
         [0135]    It is apparent from viewing  FIG. 10  that the brightness of light rapidly falls down as indicated by a dash-and-dot line in a region expanding from a boundary position x 1  between the center side of the lower frame  6  and the concave portion  6   o   1  up to the concave portion  6   o   1  of lower frame  6 . 
         [0136]    To cope with this phenomenon, a white-dot print pattern that uses white color ink shown in  FIG. 11B  is formed in a region W 1  (see  FIGS. 10 and 11A ) which is from a left-side end portion x 0  of the display screen G on either a surface  7   a  on the fluorescent tube  4  side of the light diffusion plate  7  shown in  FIG. 10  or a surface  8   a   1  on the light diffusion plate  7  side of the optical sheet  8  up to a center-side position x 2  which exceeds the center-side boundary x 1  of the concave portions  6   o   1  of lower frame  6 . 
         [0137]    This white-dot print pattern is the one that partially suppresses the light of the fluorescent tubes  4  due to reflection and, at the same time, illuminates dark portions by such reflected light to thereby prevent rapid change in brightness of the light. 
         [0138]    Additionally,  FIG. 11A  is a diagram showing regions W 1  and W 2  with the print pattern being formed on the light diffusion plate  7  or the optical sheet  8  at the display screen G shown in  FIG. 1A , and  FIG. 11B  is a diagram showing a print pattern of an O portion of  FIG. 11A  and also showing a print pattern at P portion of  FIG. 11A . 
         [0139]    As shown in  FIG. 11B , the white-dot print pattern is such that middle-sized white dots are formed in an area extending from the center-side position x 2  to the terminate end side, wherein the position x 2  is more closer to the center side than the center-side boundary x 1  of the concave portion  6   o   1  of the lower frame  6  shown in  FIG. 10 ; large-size white dots are formed in an area of from a nearby position of the center-side boundary x 1  of the concave portion  6   o   1  of the lower frame  6  up to the end part side; and, small-size white dots are formed in an area covering from an almost mid location of the concave portion  6   o   1  region of lower frame  6  up to the terminate end side. The formation of these small-size white dots is stopped on near side of the left end position x 0  of the display screen G. 
         [0140]    By forming this white-dot print pattern, it becomes possible to moderate the change in light brightness as indicated by a solid line of  FIG. 10 . 
         [0141]    Note here that as shown in  FIGS. 11A and 11B , similar effects are obtainable by forming a similar white-dot print pattern in a region W 2  on the display screen G, which region is bilaterally symmetrical with the region W 1 . 
         [0142]    Also note that in the case of forming the concave portions  26   o   3 ,  26   o   4  at the upper and lower ends of the lower frame  26  as shown in  FIGS. 4A-4C  of the second embodiment, it is possible, in a similar manner to the solid line of  FIG. 10 , to moderate the change in light brightness by forming similar white-dot print patterns at the upper and lower end parts. 
         [0143]    Obviously, it is also possible to form the above-stated print pattern at at least either one of the right and left ends or the upper and lower ends. 
         [0144]    Although in the fifth embodiment the case of using the white ink is explained as an example, any available ink of other colors except the white-color ink may be used as far as this ink is high in reflectivity. 
         [0145]    Additionally, although in the fifth embodiment the explanation was given by taking as an example the case of forming the white-dot print pattern on either the surface  7   a  on the fluorescent tube  4  side of the light diffusion plate  7  or the surface  8   a   1  on the light diffusion plate  7  side of the optical sheet  8 , certain effects are obtainable even when forming the white-dot print pattern at other locations; for example, on a surface  7   b  on the fluorescent tube  4  side of the light diffusion plate  7  or a surface  8   a   2  of the optical sheet  8   a  or on an optical sheet(s)  8   b,    8   c.    
         [0146]    While the first to fifth embodiments have been explained individually, arrangements of any ones of the first to fifth embodiments may be selected appropriately for use in combination when the need arises. 
         [0147]    It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.