the following will describe in detail a light source device and a display apparatus including the light source device according to the present invention with reference to the drawings illustrating some embodiments thereof . fig3 is a front view of a display apparatus according to embodiment 1 , fig4 is an exploded perspective view illustrating a configuration of major components of the display apparatus according to embodiment 1 , and fig5 is a longitudinal sectional view taken on line v - v in fig3 . the display apparatus of embodiment 1 is a liquid crystal display apparatus including a rectangular plate - shaped liquid crystal panel ( display panel ) 1 and an edge light type light source device . the light source device of embodiment 1 includes a light source unit 2 , a light guide plate 3 , a panel chassis ( frame member ) 5 , bl chassis ( holding member ) 6 , a heat spreader ( heat dissipator ) 7 , and the like . the light source unit 2 has a strip - shaped substrate 21 and a light source 20 mounted on the substrate 21 . the light source 20 is , for example , a plurality of light emitting diodes ( leds ) mounted on the substrate 21 in a longitudinal direction thereof . the light source unit 2 may be a cold cathode fluorescent lamp ( ccfl ), an external electrode fluorescent lamp ( eefl ), a hot cathode fluorescent lamp ( hcfl ), or the like . the light guide plate 3 is made of a high transparency synthetic resin such as an acrylic resin or a polycarbonate resin , and is formed in a rectangular plate shape . the light guide plate 3 has an optical sheet 31 adhered to one surface thereof , and a reflection sheet 32 adhered to the other surface thereof . the reflection sheet 32 is a sheet made of a synthetic resin having high reflection properties . the optical sheet 31 is a sheet in which a diffusion sheet , a prism sheet , a polarizing sheet and the like are laminated , for example . the diffusion sheet is , for example , a film made of polyethylene terephthalate ( pet ) or a film made of a polycarbonate resin , and has a function to diffuse the incident light . the prism sheet is formed by , for example , molding regular prism patterns with an acryl resin on one surface of a sheet material made of polyester . the polarizing sheet is , for example , a film made of polyethylene terephthalate , and has a function to convert the incident light into a linearly polarized light . the optical sheet 31 may be held with a state of being spaced appropriately from one surface of the light guide plate 3 , in addition to the configuration of being adhered to the one surface of the light guide plate 3 . the light source unit 2 having the above - described configuration is , for example , disposed to face a lower end surface of the light guide plate 3 so that the light from the light source 20 is made incident thereon . the light source device may include two light source units 2 , and in the case of including two light source units 2 , for example , the light source units 2 may be respectively disposed to face right and left end surfaces of the light guide plate 3 , or may be respectively disposed to face upper and lower end surfaces of the light guide plate 3 . the bl chassis 6 is a metallic member having a shape in which one sidewall ( a sidewall on a front long side in fig4 ) and a part of a bottom plate connecting to the one sidewall are cut from a dish - shape . the bl chassis 6 has the bottom plate which is a rectangular flat plate having a slightly smaller length in a short side direction than the light guide plate 3 on which the optical sheet 31 and the reflection sheet 32 are adhered ( hereinafter , briefly referred to as the light guide plate 3 ), and a protrusion plate 60 which vertically stands from one long side and two short sides of the bottom plate to the same direction as each other . further , the protrusion plates which stand from the two short sides are provided so as to be slightly longer than the short sides of the bottom plate . the heat spreader 7 is a metallic member which has a rectangular support plate 70 , and protrusive plates 71 and 72 protruding in the same direction as each other from two long sides of the support plate 70 , and has a cross - section formed in substantially a u - shape at a plane orthogonal to the long side . one protrusive plate 72 protrudes longer than the other protrusive plate 71 , and has a light guide plate pressing portion 73 which abuts against the light guide plate 3 as described below at a place facing a protruded end of the other protrusive plate 71 . in addition , the protrusive plate 72 has a recess 72 a along the protruded end at an outer surface on the protruded end side thereof . it is preferable that the heat spreader 7 is made of metal having a high thermal conductivity such as aluminum or cupper , so as to efficiently release heat . the light source unit 2 disposed to face a lower end surface of the light guide plate 3 is supported in such a way that a back surface of the substrate 21 ( a rear surface of a mounding surface of the light source 20 ) is attached to the support plate 70 of the heat spreader 7 . further , the light source unit 2 is attached to a surface of the support plate 70 on a side in which the protrusive plates 71 and 72 protrude , and is in a state of being covered with the support plate 70 and the protrusive plates 71 and 72 . the protruded ends of the protrusive plates 71 and 72 overlap with the end edge parts of the light guide plate 3 on the light source unit 2 side , and the light guide plate pressing portion 73 provided on the protrusive plate 72 abuts against an end edge part of the reflection sheet 32 on the light source unit 2 side . as illustrated in fig5 , the bl chassis 6 is provided with a recess on an upper surface of the bottom plate along an end surface of the bottom plate , which is configured to be engaged with the recess 72 a of the heat spreader 7 . thereby , the heat spreader 7 engages with the recess of the bl chassis 6 by the recess 72 a while holding the light source unit 2 , and supports the light guide plate 3 together with the bl chassis 6 from the reflection sheet 32 side . the panel chassis 5 is a rectangular frame - shaped resin member slightly larger than the light guide plate 3 , and has a light guide plate pressing portion 51 which abuts against the light guide plate 3 and is formed along an opening portion of the panel chassis 5 . the panel chassis 5 covers the peripheral edge of the light guide plate 3 from the optical sheet 31 side . further , the panel chassis 5 covers the peripheral edge of the light guide plate 3 , in a state in which the light source unit 2 and the light guide plate 3 are supported by the heat spreader 7 and the bl chassis 6 as described above . thereby , the light source unit 2 is supported by the bl chassis 6 and the panel chassis 5 through the heat spreader 7 . when the panel chassis 5 covers the peripheral edge of the light guide plate 3 , the light guide plate pressing portion 51 abuts against the peripheral edge of the optical sheet 31 , and an inner peripheral surface of the panel chassis 5 abuts against outer peripheral surfaces of the support plate 70 and the protrusive plate 71 of the heat spreader 7 . specifically , the support plate 70 abuts against the inner surface of one sidewall ( a lower sidewall ) of the panel chassis 5 , and the protrusive plate 71 abuts against the inner surface of the panel chassis 5 on a front side thereof . thereby , a lower end edge part of the light guide plate 3 are clamped by the light guide plate pressing portion 51 of the panel chassis 5 and the light guide plate pressing portion 73 of the heat spreader 7 . further , the peripheral edge parts other than the lower end side of the light guide plate 3 are clamped by the light guide plate pressing portion 51 of the panel chassis 5 and the bl chassis 6 . by the above - described configuration , the light source unit 2 and the light guide plate 3 are supported by the panel chassis 5 , the heat spreader 7 and the bl chassis 6 . thereby , the light source device which irradiates the liquid crystal panel 1 with light is achieved by the light source unit 2 , the light guide plate 3 , the optical sheet 31 , the reflection sheet 32 , the panel chassis 5 , the heat spreader 7 and the bl chassis 6 . the liquid crystal panel 1 is formed by arranging a plurality of liquid crystal elements in a two - dimensional matrix shape , for example . the liquid crystal panel 1 is formed in a rectangular plate shape having a size substantially the same as the light guide plate 3 , and is placed on the panel chassis 5 in a state where one surface thereof faces the light guide plate 3 ( optical sheet 31 ). the bezel 4 is a frame - shaped metallic member formed in the same shape and having substantially the same size as the panel chassis 5 , and has a panel pressing portion 41 which abuts against the liquid crystal panel 1 and is formed along an opening portion of the bezel 4 . the bezel 4 covers a peripheral edge of the liquid crystal panel 1 placed on the light source device ( panel chassis 5 ) from an outside ( a display screen side ). further , the bezel 4 covers the liquid crystal panel 1 by abutting against the peripheral edge of the display screen of the liquid crystal panel 1 with the panel pressing portion 41 and abutting against the outer peripheral surface of the panel chassis 5 with an inner peripheral surface thereof . thus , the liquid crystal panel 1 is clamped by the panel pressing portion 41 of the bezel 4 and the peripheral edge part of the opening portion of the panel chassis 5 . thereby , the display apparatus illustrated in fig3 to 5 is formed . in the display apparatus having the above - described configuration , light emitted from the light source unit 2 ( the light source 20 ) is made incident in the light guide plate 3 through the lower end surface thereof , and is reflected by the reflection sheet 32 , then passes through the light guide plate 3 and the optical sheet 31 to irradiate the liquid crystal panel 1 with flat light . further , the light guide plate 3 may have patterns formed on a surface thereof on which the optical sheet 31 is provided , so as to appropriately direct the emitted light in the liquid crystal panel 1 direction . in this case , the light emitted from the light guide plate 3 can be transferred to the optical sheet 31 more uniformly . in embodiment 1 , a space in which the light source unit 2 is disposed is covered with the heat spreader 7 . specifically , the protrusive plate 71 and the support plate 70 of the heat spreader 7 are provided between the light source unit 2 and the inner surface of the panel chassis 5 facing the light source unit 2 . the heat spreader 7 is made of a metal , and does not allow the light from the light source unit 2 to be transmitted therethrough , such that the light from the light source unit 2 does not reach the panel chassis 5 side by the protrusive plate ( a light shielding portion ) 71 . that is , the light from the light source unit 2 does not reach the front side ( the display screen side of the display apparatus ) of the panel chassis 5 . conventionally , the light from the light source unit 2 is transmitted through the panel chassis 5 , and passes through a gap between the bezel 4 and the liquid crystal panel 1 , such that light leakage occurs , as well as , the light transmitted through the panel chassis 5 is made incident in the liquid crystal panel 1 , such that luminance at one end part of the liquid crystal panel 1 is increased . however , in embodiment 1 , since the light from the light source unit 2 is shielded ( light shielded ) by the protrusive plate 71 of the heat spreader 7 , it does not reach the panel chassis 5 , and as a result , the light does not pass through between the bezel 4 and the liquid crystal panel 1 . thereby , according to embodiment 1 , in the liquid crystal panel 1 , the light leakage does not occur at the end part ( the lower end part in the example of embodiment 1 ) in which the light source unit 2 is provided , and thus the luminance at the end part is not increased . in addition , in embodiment 1 , since the light source device is formed by using the heat spreader 7 which is originally required in the display apparatus , an increase of manufacturing and assembling processes or an increase of costs do not occur . hereinafter , a display apparatus according to embodiment 2 will be described . the display apparatus of embodiment 2 is different from the above - described display apparatus of embodiment 1 in terms of only the configuration of a heat spreader 7 . accordingly , only the heat spreader 7 will be described , and the other components thereof will be denoted by the same reference numerals as embodiment 1 , and will not be described . fig6 is a perspective view of a heat spreader 7 according to embodiment 2 , and fig7 is a longitudinal sectional view taken on line v - v in fig3 . the heat spreader 7 of embodiment 2 has the same configuration as the above - described heat spreader 7 of embodiment 1 , and further has a groove 74 formed in an upper surface ( a surface facing the light source unit 2 ) of the protrusive plate 72 at a place connecting to the support plate 70 . by such the configuration , when sliding the substrate 21 of the light source unit 2 along the groove 74 , the light source unit 2 can be attached at an appropriate position with respect to the support plate 70 of the heat spreader 7 . by the above - described configuration , also in embodiment 2 , since the light from the light source unit 2 is shielded ( light shielded ) by the protrusive plate 71 of the heat spreader 7 , it does not reach the panel chassis 5 . thereby , in the liquid crystal panel 1 , the light leakage does not occur at the end part on a side in which the light source unit 2 is provided , and thus the luminance at the end part is not increased . in addition , also in embodiment 2 , an increase of manufacturing and assembling processes or an increase of costs do not occur . in the above - described embodiments 1 and 2 , for the light source device according to the present invention , the light source device for the liquid crystal display apparatus has been described as an example , but the present invention may be applied , for example , to other light source device such as a light source device ( lighting device ) for indoor lighting . as this description may be embodied in several forms without departing from the spirit of essential characteristics thereof , the present embodiments are therefore illustrative and not restrictive , since the scope is defined by the appended claims rather than by the description preceding them , and all changes that fall within metes and bounds of the claims , or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims . in addition , technical features described in each embodiment may be combined with each other . it is noted that , as used herein and in the appended claims , the singular forms “ a ”, “ an ”, and “ the ” include plural referents unless the context clearly dictates otherwise .