Patent Publication Number: US-2012026427-A1

Title: Image display apparatus and method of assembling the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2010-173073, which was filed on Jul. 30, 2010, the contents of which are incorporated herein by reference in its entirety. 
     BACKGROUND OF THE TECHNOLOGY 
     1. Field of the Technology The present technology relates to an image display apparatus including a diffusing plate that diffuses a light from the light source and an optical sheet, and a method of assembling the image display apparatus. 
     2. Description of the Related Art 
     In an image display apparatus such as a liquid crystal display apparatus are overlapped a diffusing plate, an optical sheet and the like between a display panel and a light source, and light which is illuminated to the display panel from the light source is controlled to improve image quality of an display image. 
     A display apparatus described in Japanese Unexamined Patent Publication JP-A 2006-24483 includes a diffusing plate and an optical sheet, and projections are provided on outer perimeters of the diffusing plate and the optical sheet. 
     A display apparatus described in Japanese Unexamined Patent Publication JP-A 2008-103334 includes a light source unit, a plurality of optical sheets and a mould frame, and each of the optical sheets includes a main body section and a sheet guide section that projects to an outer perimeter. The mould frame is provided with a sheet guide groove where the sheet guide section of the optical sheet is accommodated. 
     Since the diffusing plate and the optical sheet are made of resin, these members are easily expanded and deformed by heat generated from the light source. Thus, the diffusing plate and the optical sheet are not fixed to a frame using a fixing member. The diffusing plate and the optical sheet are provided with projecting sections and the projecting sections are fitted into holes that are provided in the frame so that the diffusing plate and the optical sheet are retained on the frame as described in JP-A 2006-24483 and JP-A 2008-103334. 
     Specifically, in a display apparatus of which widths of a bezel and a frame when viewed from a display surface side are made as small as possible, since a projection length of the projecting sections is required to be short, outer perimeter dimensions of the body section of the optical sheet and the diffusing plate, and a dimension of an inner perimeter surface of the frame are required to be precisely concordant with each other to be retained the optical sheet on the frame. 
     As in the display apparatus described in JP-A 2006-24483, in a case where the projecting sections are provided at four sides of the diffusing plate and the optical sheet, the assembling of the display apparatus is difficult. If the projecting sections of the optical sheet are fitted into the holes that are provided in the frame, an operation that deforms the optical sheet and fits all projections into the holes is required. However, the operation that fits the projections that are provided at four sides into the holes is difficult. Also, if, in a state where the diffusing plate and the optical sheet are overlapped with each other, it is tried to slide these members and fit the projecting sections of the diffusing plate and the projections of the optical sheet into the holes, it is difficult to fit the projections into the holes simultaneously since the diffusing plate is heavy and the optical sheet is light. 
     SUMMARY OF THE TECHNOLOGY 
     An object of the technology is to provide an image display apparatus and a method of assembling the same capable of easily assembling without causing degradation of image quality. 
     The technology provides an image display apparatus, comprising: 
     a liquid crystal panel having a liquid crystal element, the liquid crystal panel displaying an image on one surface side thereof by the liquid crystal element; 
     a base arranged on another surface side of the liquid crystal panel; 
     a light source provided in the base, the light source illuminating light to the liquid crystal panel from the other surface side of the liquid crystal panel; 
     a diffusing plate provided between the light source and the liquid crystal panel, the diffusing plate diffusing light that is outputted from the light source, and having a body section of a rectangular shape, and diffusing plate projecting sections that project to an outside in parallel with a main surface of the body section at four sides of the rectangular shape when the body section is viewed in a thickness direction thereof; 
     a plurality of optical sheets provided between the diffusing plate and the liquid crystal panel, the plurality of optical sheets changing optical characteristics of light that has passed through the diffusing plate, and including a first optical sheet having a first sheet body section of a rectangular thin plate shape and first sheet projecting sections projected to an outside in parallel with a main surface of the first sheet body section only at two long sides parallel to each other, among four sides that make a rectangular shape when the first sheet body section is viewed from a thickness direction thereof, and a second optical sheet having a second sheet body section of a rectangular thin plate shape and second sheet projecting sections projected to an outside in parallel with a main surface of the second sheet body section only at two short sides parallel to each other, among four sides that make a rectangular shape when the second sheet body section is viewed from a thickness direction thereof; and 
     a fixing structure of a frame shape contacting and retaining the liquid crystal panel, the diffusing plate and the optical sheet from an outside in a planar direction thereof, respectively, the fixing structure including fit holes which are opened in an inner perimeter surface thereof and into which the diffusing plate projecting sections and the sheet projecting sections are fitted. 
     The diffusing plate is provided between the light source and the liquid crystal panel and the light that is outputted from the light source is diffused at the diffusing plate. Also, the diffusing plate has a body section of a rectangular shape and diffusing plate projecting sections that project to the outside in parallel with the main surface of the body section at four sides that have a rectangular shape when the body section is viewed from the thickness direction thereof. 
     The optical sheet is provided between the diffusing plate and the liquid crystal panel and changes the optical characteristics of the light that has passed through the diffusing plate. The first optical sheet has a first sheet body section of a rectangular thin plate shape and first sheet projecting sections that project to the outside in parallel with the main surface of the first sheet body section only at two long sides parallel to each other, among four sides that have a rectangular shape when the first sheet body section is viewed from the thickness direction thereof. The second optical sheet has a second sheet body section of a rectangular thin plate shape and second sheet projecting sections that project to the outside in parallel with the main surface of the second sheet body section only at two short sides parallel to each other, among four sides that have a rectangular shape when the second sheet body section is viewed from the thickness direction thereof. The fixing structure includes the fit holes which are opened in the inner perimeter surface and into which the diffusing plate projecting sections and the sheet projecting sections are fitted. 
     Accordingly, after center sections of the side not containing the sheet projecting sections are in a bending state, the first optical sheet and the second optical sheet are returned to a planar state, and it is possible to fit the first sheet projecting sections and the second sheet projecting sections into the fit holes. 
     Also, the first sheet projecting sections and the second sheet projecting sections are fitted into the fit holes along with the diffusing plate projecting sections, and the light that has passed through only the diffusing plate is not outputted, so that unevenness of brightness is generated. 
     Accordingly, it is possible to assemble the image display apparatus easily without deteriorating image quality. 
     Further, it is preferable that opposite end portions of the diffusing plate projecting sections and the sheet projecting sections in a projection direction thereof are formed in a taper shape. 
     Opposite end portions of the diffusing plate projecting sections and the sheet projecting sections in the projection direction thereof are formed in a taper shape, so that it is possible to prevent generation of deformation or damage of the projecting sections due to contact with the fit holes when the projections are fitted into the fit holes. 
     Further, it is preferable that the first optical sheet is provided on the liquid crystal panel side with respect to the second optical sheet. 
     The first optical sheet is provided on the liquid crystal panel side with respect to the second optical sheet. 
     Since the sheet projecting sections are provided at the long sides, the first optical sheet is bent a little in a using state and it is also possible to prevent contact with the liquid crystal panel. 
     Further, it is preferable that at least one of the first sheet projecting sections and the second sheet projecting sections of the first optical sheet and the second optical sheet is provided at asymmetrical positions in two sides parallel to each other. 
     At least one of the first sheet projecting sections and the second sheet projecting sections of the first optical sheet and the second optical sheet is provided at asymmetrical positions in two sides parallel to each other. 
     There is a case where surface states of the optical sheet are different between the back surface and the front surface, and in this case, directions of arrangement of the optical sheets are predetermined. The sheet projecting sections are at the asymmetrical positions, whereby it is possible to prevent a failure of an operation in which the front and the back surfaces are arranged differently. 
     Further, it is preferable that the fixing structure is formed of a plurality of fixing members. 
     The fixing structure is formed of a plurality of fixing members. For example, the diffusing plate can be arranged in a state where the fixing member of a portion of the fixing structure is separated. 
     Further, it is preferable that the optical sheet further includes a third optical sheet of a rectangular thin plate shape and third sheet projecting sections projected to an outside in parallel with a main surface of the third body section only at two long sides parallel to each other, among four sides that have a rectangular shape when the third sheet body section is viewed from a thickness direction thereof, and 
     the first sheet projecting sections of the first optical sheet are provided only in one side area of two sides in a longitudinal direction thereof, the third sheet projecting sections of the third optical sheet are provided only in the other side area of two sides in the longitudinal direction thereof, and the first optical sheet and the third optical sheet have rotational symmetry. 
     The first sheet projecting sections of the first optical sheet are provided only in one side area of two sides in the longitudinal direction thereof, the third sheet projecting sections of the third optical sheet are provided only in the other side area of two sides in longitudinal direction thereof. The first optical sheet and the third optical sheet are constituted so as to have rotational symmetry. 
     The first optical sheet and the third optical sheet are substantially identical to each other and may be used in a state of rotation of 180°. 
     Further, the technology provides a method of assembling the image display apparatus mentioned above, comprising: 
     a first step of arranging the diffusing plate on the fixing structure, 
     a second step of contacting the second sheet projecting sections with a surface of the diffusing plate that is arranged in a state where the second sheet body section is bent at a center of the long side, returning the bending state of the second sheet body section to a planar state, and fitting the second sheet projecting sections into the fit holes of the fixing structure, 
     a third step of contacting the first sheet projecting sections with a surface of the second optical sheet that is arranged in a state where the first sheet body section is bent at a center of the short side, returning the bending state of the first sheet body section to a planar state, and fitting the first sheet projecting sections into the fit holes of the fixing structure, and 
     a fourth step of arranging the liquid crystal panel on the fixing structure. 
     At the second step, the second projecting sections come in contact with the surface of the diffusing plate that is arranged in a state where the second sheet body section is bent at the center of the long side, the bending state of the second sheet body section returns to the planar state, and the second sheet projecting sections are fitted into the fit holes of the fixing structure. At the third step, the first sheet projecting sections come in contact with the surface of the second optical sheet that is arranged in a state where the first sheet body section is bent at the center of the short side, the bending state of the first sheet body section returns to the planar state, and the first sheet projecting sections are fitted into the fit holes of the fixing structure. 
     Accordingly, it is possible to assemble the image display apparatus easily assembled without deteriorating image quality. 
     Further, it is preferable that at the second step and the third step, shafts are arranged on lower sides of the first sheet body section and the second sheet body section, and the first optical sheet and the second optical sheet are in a bending state by the shafts, the shafts are then lowered, and the shafts are drawn out in an extending direction thereof, whereby the first projecting sections and the second projecting sections are fitted into the fit holes. 
     At the second step and the third step, shafts are arranged on lower sides of the first sheet body section and the second sheet body section, and the first optical sheet and the second optical sheet are in a bending state by the shafts, the shafts are then lowered, and the shafts are drawn out in the extending direction thereof, whereby the first sheet projecting sections and the second sheet projecting sections are fitted into the fit holes. 
     Accordingly, an assembling process can be easily automated without operator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other and further objects, features, and advantages of the technology will be more explicit from the following detailed description taken with reference to the drawings wherein: 
         FIG. 1  is a cross-sectional view illustrating an image display apparatus according to an embodiment; 
         FIG. 2  is an exploded perspective view illustrating the construction of the image display apparatus; 
         FIGS. 3A to 3C  are plan views of an optical sheet and a diffusing plate; 
         FIGS. 4A and 4B  are exterior views illustrating the constitution of a displacement preventing member; 
         FIGS. 5A to 5C  are drawings illustrating an arrangement procedure of the diffusing plate; 
         FIGS. 6A to 6D  are drawings illustrating an arrangement procedure of the optical sheet; 
         FIG. 7  is a plan view illustrating an optical sheet according to another embodiment; 
         FIGS. 8A and 8B  are plan views illustrating two optical sheets in another embodiment in which three or more optical sheets are used; and 
         FIG. 9  is a drawing illustrating a sheet projecting section having a taper portion. 
     
    
    
     DETAILED DESCRIPTION 
     Now referring to the drawings, preferred embodiments are described detail below. 
       FIG. 1  is a cross-sectional view illustrating an image display apparatus  10  according to an embodiment. In  FIG. 1 , a light source and a lamp holder are omitted.  FIG. 2  is an exploded perspective view illustrating the construction of the image display apparatus  10 . 
     The image display apparatus  10  includes a liquid crystal panel  11  in the embodiment and is a liquid crystal display apparatus that displays an image. Referring to  FIGS. 1 and 2 , the image display apparatus  10  comprises the liquid crystal panel  11 , a chassis  12 , a fixing structure  13 , a frame section  16 , a connecting member  17 , an optical sheet  40  and a diffusing plate  41 . 
     In the first embodiment, the image display apparatus  10  is an apparatus that displays the image on a display screen by outputting image information in a television, a personal computer or the like. The liquid crystal panel  11  having a liquid crystal element forms the display screen and the liquid crystal panel  11  is formed in a plate shape. In the liquid crystal panel  11 , two directions of the thickness direction Z are defined as a front side Z 1  and a back side Z 2 . 
     The liquid crystal panel  11  has the liquid crystal element and displays the image on an one surface  18  side by the liquid crystal element. The chassis  12  is a base that is used to fix the liquid crystal panel  11  and is arranged on the other surface  19  side with respect to the liquid crystal panel  11 . One surface  18  side is the front side Z 1  and the other surface  19  side is the back side Z 2 . 
     The fixing structure  13  comprises a plurality of members that assists fixing of the liquid crystal panel  11  and it is desirable that the plurality of members is constituted by dividable members. The fixing structure  13  includes one or more displacement preventing members  21  and the displacement preventing member  21  has an opposing section  22  and a contacting section  24 . The opposing section  22  is opposed from the other surface  19  side to at least a portion of the outer perimeter portion of the liquid crystal panel  11  when the liquid crystal panel  11  is viewed from the thickness direction Z. The contacting section  24  contacts with the outer perimeter portion from the outside of the liquid crystal panel  11  in a planar direction thereof. The frame section  16  is opposed to the outer perimeter portion of the liquid crystal panel  11  on one surface  18  side and holds the outer perimeter portion in corporation with the fixing structure  13 . Accordingly, a relative displacement of the liquid crystal panel  11  toward one surface  18  side with respect to the frame section  16  is prevented. The connecting member  17  connects the displacement preventing member  21  to the chassis  12 . 
     The liquid crystal panel  11  is formed in a rectangular plate shape and the displacement preventing member  21  contacts with a portion that forms at least one side of the outer perimeter portion of the liquid crystal panel  11  from the outside of the liquid crystal panel  11  in the planar direction thereof. Accordingly, in a case where the displacement preventing member  21  is provided in the portion that forms the one side, the displacement preventing member  21  is separable from a member that constitutes the fixing structure  13  at the other three sides. 
     The portion that constitutes at least one side where the displacement preventing member  21  contacts with one side from the outside of the liquid crystal panel  11  in the planar direction thereof, includes one of a pair of end portions  26  that forms short sides of the liquid crystal panel  11 . 
     The displacement preventing member  21  has an engaging section that engages with the chassis  12 , and the chassis  12  has an engaged section that is engaged with the engaging section. In a state where the engaging section engages the engaged section and connection of the chassis  12  and the displacement preventing member  21  by the connecting member  17  is released, the contacting section  24  can be angularly displaced with respect to the chassis  12  about the engaged section as the fulcrum. Also, the contacting section  24  is close to and is apart from the liquid crystal panel  11  by an angular displacement. 
     The connecting member  17  is constituted by a screw member and connects the displacement preventing member  21  to the chassis  12  by screwing to the displacement preventing member  21 . Also, the screw member advances and retreats with respect to the displacement preventing member  21  according to an angular displacement with respect to the displacement preventing member  21 . The contacting section  24  of the displacement preventing member  21  angularly displaces according to the advancing and retreating of the screw member with respect to the displacement preventing member  21 . 
     The image display apparatus  10  displays an image visibly when viewed from the front side Z 1 . In the image display apparatus  10 , the terms “the front side” (Z 1 ) and “the back side” (Z 2 ) regarding plate shape components that are arranged in parallel with the liquid crystal panel  11  are used as indicating directions the same as those in the case of the liquid crystal panel  11 . In the image display apparatus  10 , the frame section  16  that surrounds the perimeter of the liquid crystal panel  11  from the outside of the planar direction thereof is a so-called thin bezel. For example, when the image display apparatus  10  is used in a multi-display system, a plurality of image display apparatuses  10  is arranged along one direction or in matrix. At this time, a portion that corresponds to a boundary line of the image display apparatuses  10  adjacent to each other, in other words, the frame section  16  is a non-display portion where the image is not displayed. In the multi-display, an image to be displayed on the image display apparatuses  10  adjacent to each other is originally a sequential image, however in a case where the width of the frame section  16  when viewed from the Z direction is large, the width of the non-display portion becomes large. In the image display apparatus  10  used for the multi-display system, in order to make the width of the non-display portion as small as possible, the frame section  16  having a small width, that is, thin bezel is required. The image display apparatus  10  of the first embodiment is a thin-bezel liquid crystal display apparatus in which a diagonal length of the liquid crystal panel  11  is 60 inches and an aspect ratio is 9:16. 
     The image display apparatus  10  includes a plurality of light sources  32  that are arranged on the back side with respect to the liquid crystal panel  11  (refer to  FIG. 2 ). The plurality of the light sources  32  are attached to the chassis  12 . Light outputted from the light source  32  passes through the diffusing plate  41  and the optical sheet  40 . Furthermore, the light is outputted on the front side with respect to the image display apparatus  10  through the liquid crystal panel  11  and is used as display light that performs the image display. As the light source  32 , various light emitting members such as a fluorescent tube or an LED (Light Emitting Diode) may be used. The frame section  16  constitutes a portion of a housing that accommodates the liquid crystal panel  11 , the chassis  12 , the fixing structure  13 , the connecting member  17  and the light source  32 . 
     The housing of the first embodiment has the frame section  16  and a back side member that constitutes the housing together with the frame section  16 . The frame section  16  is arranged so as to extend to the outside of the liquid crystal panel  11  in the planar direction viewed from the front side Z 1 , and the frame section  16  alone or together with the back side member defines an interior space. 
     The frame section  16  and the liquid crystal panel  11  are formed in the rectangular shape when the image display apparatus  10  is viewed from the front side Z 1 . The rectangular shape may be arranged in landscape orientation or arranged in portrait orientation as a usual posture when the image display apparatus  10  displays the image. In the first embodiment, the rectangular shape is arranged in landscape orientation. The frame section  16  includes a plate shape portion  36  that is perpendicular to the thickness direction Z and an outer perimeter portion  37  that surrounds the liquid crystal panel  11  from the outside in the planar direction thereof. The plate shape portion  36  holds the liquid crystal panel  11  in corporation with the fixing structure  13 . 
     The liquid crystal panel  11  includes two substrates  11   a  and is formed in the rectangular plate shape when the liquid crystal panel  11  is viewed from the thickness direction Z. The liquid crystal panel  11  includes switch elements such as TFTs (Thin Film Transistors), and the liquid crystal is injected into a gap between the two substrates  11   a . The liquid crystal display panel is irradiated with the light from the light source  32  of the back side as backlight so that the display function is exerted. A driver for controlling the driving of the pixel (a source driver) in the liquid crystal panel  11 , various elements and wirings are provided on the two substrates  11   a.    
     The fixing structure  13  is arranged on the back side with respect to the liquid crystal panel  11  and arranged on the front side with respect to the chassis  12 , and is attached to the chassis  12 . The structure of the fixing structure  13  is described below in detail. The optical sheet  40 , the diffusing plate  41 , the lamp holder  42 , the light source  32  and a reflecting sheet  43  are arranged between the fixing structure  13  and the chassis  12 . The light source  32  includes, for example, a plurality of fluorescent tubes  38  and the lamp holder  42  attaches the fluorescent tubes  38  to the chassis  12 . The diffusing plate  41  is arranged on the front side with respect to the fluorescent tubes  38  and the optical sheet  40  is arranged on the front side of the diffusing plate  41 . The diffusing plate  41  and the optical sheet  40  are arranged in parallel with the liquid crystal panel  11 . 
     The diffusing plate  41  diffuses light that is emitted from the fluorescent tubes  38  in the planar direction thereof so that brightness is prevented from being uneven locally. The optical sheet  40  comprises a plurality of optical sheets, and in the embodiment, is constituted by two optical sheets composed of an optical sheet  40   a  and an optical sheet  40   b . The optical sheet  40  is formed of a functional resin sheet that has various functions so as to enhance the display quality. For example, the optical sheet  40  has such a function that a traveling direction of light that arrives from the back side through the diffusing plate  41  is directed to the front side. The traveling direction of light includes many planar direction components as vector components in the diffusing plate  41  so as to prevent unevenness of brightness in the planar direction. Meanwhile, the optical sheet  40  converts the traveling direction of light that includes many vector components in the planar direction to the traveling direction of the light that includes many thickness direction Z components. Specifically, the optical sheet  40  forms a large number of portions that are formed in a lens or a prism shape side by side in the planar direction so that the degree of the diffusion of the light that is traveled in the thickness direction Z is reduced. Accordingly, in the display performed by the image display apparatus  10 , it is possible to enhance brightness. 
     The chassis  12  includes a plate-shaped bottom section  39  that is perpendicular to the thickness direction Z, a sidewall section  44  that continues to the bottom section  39  and is upright from the bottom section  39 , and a plate-shaped flange section  45  that continues to a portion that is opposed to the portion that continues to the bottom section  39  among the sidewall section  44 , and extends in parallel with the bottom section  39 . The bottom section  39  is formed in the rectangular shape when viewed from the thickness direction Z. The sidewall section  44  is formed upright to the front side from the two end portions  26  that form the short sides and two end portions  27  that form the long sides among the bottom section  39 . Accordingly, four plate-shaped sidewall sections  44  are formed on the perimeter of the bottom section  39 . 
     Each of the sidewall sections  44  is formed in a strip shape and is parallel with the thickness direction Z of the bottom section  39 . A flange section  45  is connected to the end portion on the front side of the sidewall sections  44 . The flange section  45  is formed so as to extend to the outside in the planar direction with respect to the bottom section  39  when the flange section  45  is viewed from the thickness direction Z. The flange section  45  is formed in an elongated strip shape that is perpendicular to the thickness direction Z of the bottom section  39 . Accordingly, the flange sections  45  are formed in four similarly to the sidewall sections  44 . 
     Thus, four flange sections  45  are formed in the rectangular shape when the flange sections  45  is viewed in the thickness direction Z. The term “perpendicular” includes both meanings of ‘ideally perpendicular’ and ‘substantially perpendicular’, and “parallel” includes both meanings of ‘ideally parallel’ and ‘substantially parallel’. 
     The liquid crystal panel  11 , the bottom section  39  of the chassis  12 , the optical sheet  40  and the diffusing plate  41  are formed in a rectangular shape when the liquid crystal panel  11  is viewed from the thickness direction Z. Their long side directions X are parallel to each other and their short side directions Y are parallel to each other. 
     In the first embodiment, there is formed a collar section  46  projecting to the front side from an end portion of the flange section  45  that is on an opposite side to the end portion where the sidewall section  44  connects and is located outwardly in the planar direction with respect to the bottom section  39 . The collar section  46  is formed in a strip shape parallel in the thickness direction Z. The collar sections  46  are formed corresponding to three flange sections  45  among four flange sections  45 . In the first embodiment, the collar sections  46  are formed corresponding to one among two flange sections  45  that form the short sides and two flange sections  45  that form the long sides. The collar section  46  is not formed at the other one among two flange sections  45  that form the short sides. 
     The reflecting sheet  43  is arranged in contact with at least a portion of a surface on the front side of the bottom section  39  and the flange sections  45 . The reflecting sheet  43  may be arranged in contact with or may be arranged in non-contact with the sidewall section  44 . A surface of the reflecting sheet  43  that faces at least front side has high reflectivity with respect to light from the light source  32 , and ideally reflectivity of 100%. 
     The plurality of fluorescent tubes  38  are arranged near to the front side with respect to the bottom section  39  and the reflecting sheet  43  that is arranged on the front side of the bottom section  39 . Each of the fluorescent tubes  38  is arranged to extend in the long side direction X of the bottom section  39 . The lamp holders  42  fix both end portions in the longitudinal direction of the plurality of fluorescent tubes  38  to the chassis  12 . A lamp holder  42  that is arranged on one side in the longitudinal direction of the fluorescent tubes  38  and a lamp holder  42  that is arranged on the other side in the longitudinal direction of the fluorescent tubes  38  are formed in substantially rectangular parallelepiped respectively, and a surface of the rectangular parallelepiped that faces the front side is arranged perpendicular to the thickness direction Z. 
     Each of the lamp holders  42  is arranged inside with respect to the sidewall section  44  and the surface of each of the lamp holders  42  that faces the front side is arranged within one plane along with the surface of the flange section  45  that faces the front side. The outer perimeter portion of the diffusing plate  41  is arranged in contact with these surfaces. The liquid crystal panel  11 , the fixing structure  13 , the optical sheet  40 , the diffusing plate  41 , the lamp holders  42 , the fluorescent tubes  38 , the reflecting sheet  43  and the chassis  12  are arranged inside the planar direction regarding the liquid crystal panel  11  with respect to the outer perimeter portion  37  of the frame section. 
     In the first embodiment, the fixing structure  13  includes the displacement preventing member  21  and a fit fixing member  48  that is fixed by fitting to the chassis  12 . The fit fixing member  48  is fixed by fitting at least to the collar section  46  of the chassis  12 . In the first embodiment, the fit fixing member  48  includes a fitting section  51  that forms a recessed groove  49  in which the collar section  46  is to be inserted, a flat section  52  that continues to the fitting section  51  and covers the front side of the flange section  45 , and an inside section  54  that covers the sidewall section  44  of the chassis  12  from an inside perimeter side. 
     On the front side of the fitting section  51 , the opposing section  22  and the contacting section  24  are formed. The opposing section  22  faces the front surface side and is opposed to the outer perimeter portion of the liquid crystal panel  11 . The contacting section  24  projects to the front side in the outside in the planar direction with respect to the opposing section  22  and contacts with the liquid crystal panel  11  from the outside in the planar direction thereof. The opposing section  22  is a portion that holds the outer perimeter portion of the liquid crystal panel  11  in corporation with the plate shape portion  36  of the frame section  16 . Accordingly, the opposing section  22  is required to be reliably opposed to the outer perimeter portion of the liquid crystal panel  11 . Also, the opposing section  22  can easily realize the thin bezel when the opposing section  22  is set as thin as possible. 
     Regarding the opposing section  22  that contacts with the end portion forming each side of the liquid crystal panel  11 , the dimension of the opposing section  22  in a direction that is perpendicular to both of the thickness direction Z and an extension direction of each side is called as “width dimension”. As an example of the image display apparatus  10 , in a case of the image display apparatus  10  of is 60 inches, with respect to an image display area of the liquid crystal panel  11 , the dimension in the long side direction X is about 133 cm and the dimension in the short side direction Y is about 75 cm. In this case, the dimension of the opposing section  22  is set to about 3 mm. 
     The fit fixing member  48  is integrally formed in a shape that forms three sides of the rectangular shape corresponding to three sides having the collar section  46 . Accordingly, the end portion on the front side of the inside section  54  is formed to continue to the inside end portion of the flat section  52  in the planar direction thereof. The inside section  54  includes three plate shape portions parallel in the thickness direction Z of the liquid crystal panel  11 . One or more through holes  53  are formed at a portion of each of plate shape portions. The connecting member  17  that is realized by the screw member is inserted into the through hole  53  perpendicular to each of the plate shape portions. 
     The displacement preventing member  21  is provided corresponding to the portion not containing the collar section  46 , among four flange sections  45 . Accordingly, the displacement preventing member  21  is formed to define one side among four sides that form the rectangular shape. The displacement preventing member  21  is provided so as to be angularly displaceable about the portion of the flange section  45  as the fulcrum. A portion that turns to the fulcrum when the displacement preventing member  21  is angularly displaced is formed in the flange section  45  not containing the collar section  46 . Specifically, one or more recesses  56  are formed in the flange section  45  not containing the collar section  46  at one or more positions and a portion of the displacement preventing member  21  is engaged with the one or more recesses  56 . 
     The displacement preventing member  21  includes a fulcrum contacting section  57 , a connected section  58  and an angular displacement section  62 . The fulcrum contacting section  57  covers the front side of the flange section  45  and contacts with a portion that turns to the fulcrum of the angular displacement of the flange section  45 . The connected section  58  continues the fulcrum contacting section  57 , covers the sidewall section  44  of the chassis  12  from the inside perimeter side and is connected to the chassis  12  by the connecting member  17 . The angular displacement section  62  is formed in a shape upright to the front side from the flat section  52 . 
     The fulcrum contacting section  57  is constituted by a plate shape portion  59  having a plate shape parallel with the bottom section  39  of the chassis  12  and a protruding portion  63  that protrudes to the back side from the plate shape portion  59 . The protruding portion  63  is an engaging section that engages with the recess  56  formed at the flange section  45 . The recess  56  that is formed in the flange section  45  is an engaged section that is engaged with the protruding portion  63  that is formed in the displacement preventing member  21 . Accordingly, the displacement preventing member  21  can be angularly displaced about the recess  56  of the flange sections  45  as the fulcrum. 
     In the displacement preventing member  21 , the connected section  58  is formed in parallel with the thickness direction Z of the liquid crystal panel  11 , continues to the end portion of the fulcrum contacting section  57  located inside the planar direction regarding the liquid crystal panel  11  and is formed to extend on the back side. Recess portions are formed in the connected section  58  and female screws are formed in the recess portions. The recess portion is formed without penetrating the connected section  58 . Accordingly, the light is prevented from penetrating the connected section  58 . 
     The angular displacement section  62  and the connected section  58  are formed parallel in the thickness direction Z of the liquid crystal panel  11 , continues to the end portion of the fulcrum contacting section  57  located outside the planar direction regarding the liquid crystal panel  11  and is formed to extend on the front side. On the front side of the angular displacement section  62 , the opposing section  22  and the contacting section  24  are formed. The opposing section  22  faces the front side and is opposed to the outer perimeter portion of the liquid crystal panel  11 . The contacting section  24  projects to the front side in the outside of the planar direction with respect to the opposing section  22  and contacts with the liquid crystal panel  11  from the outside in the planar direction. The opposing section  22  of the displacement preventing member  21  is also a portion that holds the outer perimeter portion of the liquid crystal panel  11  in corporation with the plate shape portion  36  of the frame section  16 . Accordingly, the opposing section  22  is required to be reliably opposed to the outer perimeter portion of the liquid crystal panel  11 , and the opposing section  22  can easily realize the thin bezel when the opposing section  22  is set as thin as possible. 
     In the thickness direction Z of the liquid crystal panel  11 , the dimension of the contacting section  24  is substantially identical to the dimension of the thickness of the liquid crystal panel  11  but is set to be slightly small. Accordingly, when the plate shape member of the frame section  16  is contacted from the front side of the outer perimeter portion of the liquid crystal panel  11  and holds the liquid crystal panel  11  in corporation with the opposing section  22 , the liquid crystal panel  11  can be prevented from rattling in the thickness direction Z. 
     The optical sheet  40  comprises a sheet body section  400  having a rectangular thin plate shape and sheet projecting sections  401  that project toward the outside in a direction parallel with a main surface of the sheet body section  400 . In the embodiment, the optical sheet  40  is constituted by two optical sheets composed of the optical sheet  40   a  and the optical sheet  40   b .  FIGS. 3A to 3C  are plan views illustrating the optical sheets  40   a  and  40   b , and the diffusing plate  41 .  FIG. 3A  is a plan view of the optical sheet  40   a ,  FIG. 3B  is a plan view of the optical sheet  40   b , and  FIG. 3C  is a plan view of the diffusing plate  41 . 
     The optical sheet  40   a  is constituted by a sheet body section  400   a  having a rectangular thin plate shape and sheet projecting sections  401   a  that project toward the outside in parallel with a main surface of the sheet body section  400   a . The optical sheet  40   b  is constituted by a sheet body section  400   b  having a rectangular thin plate shape and sheet projecting sections  401   b  that project toward the outside in parallel with a main surface of the sheet body section  400   b.    
     The diffusing plate  41  is constituted by a body section  410  having a rectangular shape and diffusing plate projecting sections  411  that project toward the outside in parallel with a main surface of the body section  410 . The diffusing plate projecting sections  411  are provided in the entire of the perimeter section that forms four sides that are a rectangular when the body section  410  is viewed from the thickness direction Z. 
     Meanwhile, in the optical sheet  40 , the sheet projecting sections  401  are provided in the perimeter section that forms two sides parallel to each other among four sides that are rectangular when the sheet body section  400  is viewed from the thickness direction Z. At this time, among the two optical sheets  40   a  and  40   b , for example, the optical sheet  40   a  is provided with the sheet projecting sections  401   a  in the perimeter section that forms two long sides of the sheet body section  400   a , and the optical sheet  40   b  is provided with the sheet projecting sections  401   b  in the perimeter section that forms two short sides of the sheet body section  400   b.    
     The diffusing plate projecting sections  411  and the sheet projecting sections  401  of the optical sheet  40  are provided at positions corresponding to each other in the thickness direction Z in a state where the diffusing plate  41  and the optical sheet  40  are overlaid on each other. Also, the shape of the diffusing plate projecting section  411  and the shape of the sheet projecting section  401  of the optical sheet  40  are substantially identical to each other. The size of the sheet projecting section  401  of the optical sheet  40  and the size of the diffusing plate projecting section  411  are substantially identical to each other or the size of the sheet projecting section  401  of the optical sheet  40  is formed to be slightly larger than the size of the diffusing plate projecting section  411 . 
     The light that is outputted from the light source  32  enters not only the body section  410  but also the diffusing plate projecting section  411  of the diffusing plate  41  and passes through the diffusing plate  41  on the front side. Since the optical sheet  40  is arranged on the front side in the thickness direction with respect to the diffusing plate  41 , in a case where the sheet projecting sections  401  are not present at the positions that correspond to the diffusing plate projecting sections  411 , the light that has passed through the diffusing plate projecting sections  411  is illuminated to the liquid crystal panel  11  without passing through the sheet projecting sections  401 . Accordingly, the light that has passed through both of the diffusing plate  41  and the optical sheet  40 , and the light that has passed through only the diffusing plate  41  are present in the light that is illuminated to the liquid crystal panel  11 . The two types of illuminated lights generate unevenness of brightness. 
     In a case where the diffusing plate projecting sections  411  are provided in the entire of the perimeter that forms four sides of the body section  410  of the diffusing plate  41 , it is preferable that the sheet projecting sections  401  are provided in the entire of the perimeter that forms four sides of the sheet body section  400 , identical to the optical sheet  40 . However, when the sheet projecting sections  401  are provided in the entire of the perimeter of the optical sheet  40 , it is difficult to provide the optical sheet  40  during the assembling process. 
     The installation of the optical sheet  40  and the diffusing plate  41  to the fixing structure  13  is performed by fitting the sheet projecting sections  401  and the diffusing plate projecting sections  411  into the fit holes that are provided in the fixing structure  13 . 
       FIGS. 4A and 4B  are exterior views illustrating the constitution of the displacement preventing member  21 .  FIG. 4A  is a view illustrating the displacement preventing member  21  that is viewed from the inside perimeter side, and  FIG. 4B  is a sectional view taken along the line A-A in  FIG. 4A . Specifically, the sheet projecting sections  401  and the diffusing plate projecting sections  411  are fitted into fit holes  60  that are opened in the inside perimeter section of the fit fixing member  48  and the displacement preventing member  21 , respectively. The fit holes  60  are formed through the entire of the inside perimeter of the whole fixing structure  13 . The diffusing plate  41  is retained in the fixing structure  13  by fitting the diffusing plate projecting sections  411  that are provided in the entire of the perimeter section into the fit holes  60  and preventing the diffusing plate projecting sections  411  from loosing from the fit holes  60 . The optical sheet  40   a  is retained in the fixing structure  13  by fitting the sheet projecting sections  401   a  that are provided in the perimeter section that forms two long sides into the fit holes  60  and preventing the sheet projecting sections  401   a  from loosing from the fit holes  60 , and the optical sheet  40   b  is retained in the fixing structure  13  by fitting the sheet projecting sections  401   b  that are provided in the perimeter section that form two short sides into the fit holes  60  and preventing the sheet projecting sections  401   b  from loosing from the fit holes  60 . 
       FIGS. 5A to 5C  are drawings illustrating an arrangement procedure of the diffusing plate  41 . As shown in  FIG. 5A , the fit fixing member  48  is deformed so as to open to the outside. The diffusing plate projecting section  411  that are provided in the perimeter section that forms three sides of the diffusing plate  41  are fitted into the fit holes  60  that are provided in the fit fixing member  48 . Next, as shown in  FIG. 5B , the diffusing plate projecting sections  411  that are provided in the perimeter section that forms remained one side of the diffusing plate  41  are fitted into the fit holes  60  that are provided in the displacement preventing member  21 . Finally, as shown in  FIG. 50 , the displacement preventing member  21  is screwed the chassis  12  by the connecting members  17  and then the arrangement of the diffusing plate  41  is completed. At this time, the optical sheet  40  and the liquid crystal panel  11  are not provided. 
     Next, the procedure of setting the optical sheet  40  is described.  FIGS. 6A to 6D  are drawings illustrating an arrangement procedure of the optical sheet  40 . 
     The optical sheet  40   b  is arranged in a state where the diffusing plate  41  is arranged in the procedure as shown in  FIGS. 5A to 50 . 
     Since the optical sheet  40   b  provides the sheet projecting sections  401   b  only in the perimeter section that forms two short sides, in the operation in which the sheet projecting sections  401   b  are fitted into the fit holes  60 , as shown in  FIG. 6A , the sheet projecting sections  401   b  come in contact with the surface of the diffusing plate  41  that is arranged, in a state where the center portion of the sheet body section  400   b  in the long side is bent. Next, the bending state of the sheet body section  400   b  returns to the planar state and the sheet projecting sections  401   b  move along the surface of the body section  410 , whereby the sheet projecting sections  401   b  can be easily fitted into the fit holes  60  as shown in  FIG. 6B . 
     As described above, the optical sheet  40   b  is arranged in such a procedure. The arrangement of the optical sheet  40   a  is performed in a state where the optical sheet  40   b  is arranged. Since the optical sheet  40   a  has the sheet projecting sections  401   a  only in the perimeter section that forms two long sides, in the operation in which the sheet projecting sections  401   a  are fitted into the fit holes  60 , as shown in  FIG. 6C , the sheet projecting sections  401   a  come in contact with the surface of the optical sheet  40   b  that is arranged, in a state where the center portion of the sheet body section  400   a  in the short side is bent. Next, the bending state of the sheet body section  400   a  returns to the planar state and the sheet projecting sections  401   a  move along the surface of the sheet body section  400   b , whereby the sheet projecting sections  401   a  can be easily fitted into the fit holes  60  as shown in  FIG. 6D . 
     Furthermore, as shown in  FIG. 6A , in order to bring the sheet body section  400   b  in a bending state, a shaft  80   b  is arranged on the lower surface side of the sheet body section  400   b  and the optical sheet  40   b  is placed on the shaft  80   b . After that, the shaft  80   b  is lowered and approaches to the diffusing plate  41 , and the shaft  80   b  is drawn out in the extending direction thereof. Thus, the sheet projecting sections  401   b  can be fitted into the fit holes  60 . 
     Similarly, as shown in  FIG. 6C , in order to bring the sheet body section  400   a  in a bending state, a shaft  80   a  is arranged on the lower surface side of the sheet body section  400   a  and the optical sheet  40   b  is placed on the shaft  80   a . After that, the shaft  80   a  is lowered and approaches to the optical sheet  40   b , and the shaft  80   a  is drawn out in the extending direction thereof. Thus, the sheet projecting sections  401   a  can be fitted into the fit holes  60 . 
     Note that, in the arrangement procedure, the use of the shafts  80   a  and  80   b  is not essential. When an exterior force from two directions that are opposite to each other with respect to the optical sheet  40  are given and the sheet body section  400  is in a bending state of being convex upward, other members may be used or the operator may perform the operation manually. 
       FIG. 7  is a plan view illustrating an optical sheet  40   a  according to another embodiment. 
     In above embodiment, in the optical sheet  40   a , the sheet projecting sections  401   a  are provided at symmetrical positions at two long sides. Here, when the optical sheet  40  is arranged, the state of the front surface of the optical sheet  40  differs from the state of the back surface, so that the direction of the arrangement surface is decided in advance. Accordingly, even when the optical sheet  40   a  is arranged in a wrong state where the front surface and the back surface are reversed, the sheet projecting sections  401  can be fitted into the fit holes  60  in a case where the positions of the sheet projecting sections  401  are symmetrical, and therefore it is required that the operator confirms with their eyes at the time of arrangement or a mark is attached so as to recognize the front and the back surfaces. However, the operation error in which the front and the back surfaces are arranged differently cannot be prevented. 
     In the embodiment, as shown in  FIG. 7 , the positions in which the sheet projecting sections  402   a  are provided at two long sides are asymmetrical. In a case where the sheet projecting sections  402   a  are provided in asymmetrical, even though the front and the back surfaces are provided in reverse, the positions of the sheet projecting sections  402   a  and the engaging holes  60  are not identical to each other, the arrangement cannot be performed. Accordingly, the failure of the arrangement in which the front and the back surfaces are arranged differently can be prevented. 
     Also, the number of the optical sheets  40  of the embodiment is not limited to two, and three or more of the optical sheets may be used. At this time, as above embodiment, the sheet projecting sections may be provided at two long sides or two short sides, and for example, in two optical sheets, the sheet projecting sections are provided at the parallel two sides as the above-described embodiment, but the arrangement positions are not required to be identical to each other.  FIGS. 8A and 8B  are plan views illustrating two optical sheets  40   a  in another embodiment in which three or more optical sheets are used. 
     In the two optical sheets  40   a , the sheet projecting sections  403   a  and  404   a  are provided in the perimeter section that forms two long sides. Here, in one of the optical sheets  40   a , the sheet projecting sections  403   a  are provided in only one area in the longitudinal direction of the perimeter section that forms two long sides. In the other of the optical sheets  40   a , the sheet projecting sections  404   a  are provided in only the other area in the longitudinal direction of the perimeter section that forms two long sides. In a state where the two optical sheets  40   a  are overlaid, all of the diffusing plate projecting sections  411  and the sheet projecting sections  403   a  and  404   a  of the two optical sheets  40   a  are formed so as to correspond to each other. In the embodiment, the two optical sheets  40   a  are formed such that the positions of the sheet projecting sections  403   a  and  404   a  have rotational symmetry. Accordingly, the two optical sheets  40   a  are only different by 180° in the orientation of the planar direction, and the optical sheets  40   a  are substantially identical to each other. In other words, two optical sheets of one type are prepared and one optical sheet is rotated, whereby they may be used as the optical sheets of two types. 
     The plate shape viewed from the thickness direction of the projecting sections of the diffusing plate and the sheet projecting sections of the optical sheet may be the rectangular shape for example, however it is preferable that the plate shape is the rectangular shape having a taper portion.  FIG. 9  is a drawing illustrating a sheet projecting section  401   a  having a taper portion  405   a . The taper portion  405   a  is provided on opposite sides in the projecting direction of the sheet projecting section  401   a . The dimension in the width in the projecting direction has little gap between the fit holes  60  and the sheet projecting sections  401   a , so that it is concerned that the sheet projecting sections  401   a  come in contact with the perimeter of the fit holes  60  and then the sheet projecting section  401   a  is cracked or broken when the sheet projecting sections  401   a  are fitted into the fit holes  60 . As described above, by providing the taper portion  405   a , the contact thereof can be avoid when the sheet projecting sections  401   a  are fitted into the fit holes  60 , and after fitting, the gap between the sheet projecting sections  401   a  and the fit holes  60  can be sufficiently small. 
     The technology may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the technology being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein.