Lighting device, display device and television device

A backlight device includes an LED, a light guide plate having one edge surface as a light entrance surface, one plate surface as a light exit surface and another plate surface as an opposite plate surface, further includes a chassis having a bottom plate portion that includes a light guide plate support portion supporting the light guide plate from a side of the opposite plate surface and a light guide plate non-support portion not supporting the light guide plate from the side of the opposite plate surface, and further includes a reflection sheet having an extended reflection portion that extends closer to the LED than the light entrance surface of the light guide plate and having a cutout portion that is formed by cutting out at least a part of a portion of the extended reflection portion overlapping with the light guide plate non-support portion.

TECHNICAL FIELD

The present invention relates to a lighting device, a display device and a television device.

BACKGROUND ART

Displays in image display devices, such as television devices, are now being shifted from conventional cathode-ray tube displays to thin displays, such as liquid crystal displays and plasma displays. With the thin displays, the thicknesses of the image display devices can be reduced. Liquid crystal panels included in the liquid crystal display devices do not emit light, and thus backlight devices are required as separate lighting devices. The backlight devices are classified broadly into a direct type and an edge-light type according to mechanisms thereof. For realizing further reduction in thicknesses of the liquid crystal display devices, the edge-light type backlight devices including light guide plates are preferably used, and one described in PTL 1 below is known as one example thereof.

CITATION LIST

Patent Literature

Technical Problem

An edge-light type backlight unit described in PTL 1 above includes a light guide plate, cold cathode fluorescent lamps arranged on a side-surface side of the light guide plate, a reflection sheet arranged on a back-surface side of the light guide plate, and a reflector that supports the reflection sheet from a back surface thereof and covers the cold cathode fluorescent lamps to reflect light from the cold cathode fluorescent lamps onto the light guide plate. The reflector is provided with a convex portion, by which the reflection sheet is forced to come into contact with an edge of the light guide plate, and thus diffuse reflection of light on the edge of the light guide plate is suppressed.

However, there is a case where the convex portion as described above is difficult to be provided in the reflector due to a design, and if a hole portion or a concave portion is formed in the reflector because of the design to the contrary, the light guide plate and the reflection sheet are not supported partially. Then, a part of the reflection sheet, which overlaps with the hole portion or the concave portion, is separated from the light guide plate and the light from the cold cathode fluorescent lamps reflects off the separated part of the reflection sheet and directly enters the back surface of the light guide plate, and exits the light guide plate through a front surface thereof as it is, so that a bright region is locally generated and luminance unevenness may be caused.

SUMMARY OF INVENTION

The invention has been completed based on circumstances as described above, and aims to suppress luminance unevenness.

Solution to Problem

A lighting device of the invention includes: a light source; a light guide plate having a plate shape and including at least one edge surface as a light entrance surface through which light from the light source enters, one plate surface as a light exit surface through which the light exits the light guide plate, and another plate surface as an opposite plate surface being opposite to the light exit surface; a chassis having a bottom plate portion that includes a light guide plate support portion supporting the light guide plate from a side of the opposite plate surface and a light guide plate non-support portion not supporting the light guide plate from the side of the opposite plate surface; and a reflection member that is disposed between the opposite plate surface of the light guide plate and the bottom plate portion of the chassis and reflects the light travelling through the light guide plate toward the light exit surface, the reflection member having an extended reflection portion that extends closer to the light source than the light entrance surface of the light guide plate and having a cutout portion that is formed by cutting out at least a part of a portion of the extended reflection portion overlapping with the light guide plate non-support portion.

According to such a configuration, light emitted from the light source enters the light guide plate through the light entrance surface, and is then, for example, reflected toward the light exit surface by the reflection member that is disposed between the opposite plate surface opposite to the light exit surface and the bottom plate portion of the chassis, and thereby propagating in the light guide plate and then exits through the light exit surface. Since the reflection member has the extended reflection portion that extends so as to be closer to the light source than the light entrance surface of the light guide plate, by reflecting the light from the light source by the extended reflection portion, light entering efficiency for the light entrance surface is enhanced. On the other hand, since the bottom plate portion of the chassis has the light guide plate support portion that supports the light guide plate from the side of the opposite plate surface and the light guide plate non-support portion that does not support the light guide plate from the side of the opposite plate surface, if the portion overlapping with the light guide plate non-support portion is included in the extended reflection portion, the overlapping portion may be separated from the opposite plate surface and the separated portion reflects the light from the light source to cause the light to enter the opposite plate surface, so that the entering light is likely to directly exit from the light exit surface to cause a locally bight region, that is, luminance unevenness.

Since the cutout portion is formed in the reflection member by cutting out at least a part of the portion of the extended reflection portion overlapping with the light guide plate non-support portion, so that a portion of the extended reflection portion is less likely to be separated from the opposite plate surface of the light guide plate due to the light guide plate non-support portion, and light from the light source is less likely to reflect off the extended reflection portion and less likely to directly enter through the opposite plate surface. Thereby, the light that has entered through the opposite plate surface is less likely to directly exit the light guide plate through the light exit surface, so that luminance unevenness is hard to be caused in the light output through the light exit surface.

As aspects of the lighting device of the invention, the following preferable configurations are provided.

(1) The reflection member may include the cutout portion having a cutout edge that is flush with the light entrance surface or opposite to the light source with respect to the light entrance surface. According to such a configuration, compared to a configuration that the cutout edge of the cutout portion is closer to the light source than the light entrance surface, a portion of the extended reflection portion is less likely to be separated from the opposite plate surface of the light guide plate due to the light guide plate non-support portion, and light from the light source is less likely to reflect off the extended reflection portion and is less likely to directly enter through the opposite plate surface, thus making it possible to suppress luminance unevenness more suitably.

(2) The cutout edge of the cutout portion may be arranged opposite to the light source with respect to the light entrance surface. According to such a configuration, compared to a configuration that the cutout edge of the cutout portion is flush with the light entrance surface, the cutout edge is less likely to be closer to the light source than the light entrance surface even if positional errors may be caused in arrangement of the cutout edge of the cutout portion because of tolerance of a dimension, tolerance of attachment or the like, thus making it possible to suppress occurrence of luminance unevenness more suitably.

(3) The light guide plate non-support portion may have an edge that is opposite to the light source with respect to the light entrance surface, and the cutout edge of the cutout portion of the reflection member may be closer to the light entrance surface than the edge of the light guide plate non-support portion. According to such a configuration, reflection light reflecting off the reflection member is sufficiently secured and use efficiency of light is less likely to be lowered, compared to a configuration that the cutout edge of the cutout portion is flush with the edge of the light guide plate non-support portion and an amount of reflection light reflecting off the reflection member decreases so that use efficiency of light is lowered. Note that, when the cutout edge of the cutout portion is disposed so as to be closer to the light entrance surface than the edge of the light guide plate non-support portion, a portion of the extended reflection portion may be separated from the opposite plate surface of the light guide plate due to the light guide plate non-support portion. However, the cutout edge of the cutout portion is flush with the light entrance surface or opposite to the light source with respect to the light entrance surface and therefore, reflection light reflecting off the extended reflection portion extending closer to the light source than the light entrance surface is less likely to directly enter the light guide plate through the opposite plate surface, so that luminance unevenness is hard to occur surely.

(4) The cutout portion of the reflection member may have an opening size in a direction along the light entrance surface continuously decreasing as is farther away from the light source. According to such a configuration, an area of the reflection member, that is, an amount of reflection light reflecting off the reflection member in the direction along the light entrance surface continuously changes, so that compared to a configuration that a dimension of the cutout portion in the direction along the light entrance surface is constant or a configuration that the dimension decreases in a stepwise manner as being farther away from the light source, a dark region that may be caused in the light exit surface due to the cutout portion is less likely to be visually recognized, which is more suitable for suppressing occurrence of luminance unevenness.

(5) The cutout portion of the reflection member may have a formation range in the direction along the light entrance surface greater than a formation range of the light guide plate non-support portion in the direction along the light entrance surface. According to such a configuration, since the cutout portion extends to have a formation range overlapping with the light guide plate support portion in the direction along the light entrance surface, an amount of reflection light changes continuously between the portion of the extended reflection portion overlapping with the light guide plate non-support portion, and the portion of the extended reflection portion overlapping with the light guide plate support portion. Thereby, a dark region that may be caused in the light exit surface due to the cutout portion is less likely to be visually recognized, which is further suitable for suppressing occurrence of luminance unevenness. Even if positional errors may be caused in arrangement of the cutout portion because of tolerance of a dimension, tolerance of attachment, or the like, the cutout portion is likely to be disposed so as to appropriately overlap with the light guide plate non-support portion in the direction along the light entrance surface, so that an effect of suppressing luminance unevenness by the cutout portion is achieved more reliably.

(6) The cutout portion of the reflection member may have a formation range in the direction along the light entrance surface greater than a formation range of the cutout portion extending in the direction from the light source to the light entrance surface. According to such a configuration, even if positional errors may be caused in arrangement of the cutout portion in the direction along the light entrance surface because of tolerance of a dimension, tolerance of attachment, or the like, the cutout portion is likely to be disposed so as to appropriately overlap with the light guide plate non-support portion in the direction along the light entrance surface, so that an effect of suppressing luminance unevenness by the cutout portion is achieved more reliably. In this case, if the formation range of the cutout portion in the direction from the light source to the light entrance surface is greater than or same as the formation range of the cutout portion in the direction along the light entrance surface with dealing with the positional errors that may be caused as described above in the arrangement of the cutout portion, a formation range of the cutout portion in the direction from the light source to the light entrance surface tends to be excessively large and an amount of reflection light reflecting off the reflection member decreases, so that use efficiency of light is likely to be lowered. Compared to this, if the formation range of the cutout portion in the direction along the light entrance surface is set to be wider than the formation range at the cutout portion in the direction from the light source to the light entrance surface, an effect of suppressing luminance unevenness by the cutout portion as described above is achieved more reliably while sufficiently ensuring use efficiency of light.

(7) The light guide plate non-support portion may include an opening that is in the bottom plate portion. According to such a configuration, compared to a configuration that the light guide plate non-support portion has a recessed portion which is formed by recessing the bottom plate portion, a portion of the extended reflection portion may be likely to be separated from the opposite plate surface of the light guide plate due to the opening, which is the light guide plate non-support portion, and a distance of the separation tends to be greater. However, the reflection member including the cutout portion is less likely to have such a problem, thus making it possible to effectively suppress luminance unevenness.

(8) The lighting device may further include a light source board on which the light source is mounted and a power feed portion for feeding power to the light source on the light source board. The power feed portion may be exposed to outside through the opening of the bottom plate portion. According to such a configuration, when the opening is formed so that the opening causes the power feed portion to be exposed to outside, it is possible to cause the power feed portion to pass through the opening easily. In this manner, the opening which allows passing the power feed portion is disposed near the light source board and the light entrance surface of the light guide plate in the bottom plate portion, and thus is easy to be disposed necessarily so as to overlap also with the extended reflection portion of the reflection member. However, in the reflection member having the cutout portion, a portion of the extended reflection portion is less likely to be separated from the opposite plate surface of the light guide plate due to the opening, which is the light guide plate non-support portion, and light from the light source is less likely to reflect off the extended reflection portion and is less likely to directly enter through the opposite plate surface, thus making it possible to effectively suppress luminance unevenness.

(9) The light source board may have a light source mounting portion on which the light source is mounted, and a protrusion for power feeding protruding from the light source mounting portion in a direction from the light exit surface to the opposite plate surface, the protrusion for power feeding may have the power feed portion thereon. The power feed portion and the protrusion for power feeding may be exposed to outside through the opening of the bottom plate portion. According to such a configuration, compared to a configuration that the power feed portion is arranged in a part of the light source mounting portion and the light source mounting portion includes a portion having no light source, with a configuration including the protrusion for power feeding where the power feed portion is disposed so as to be projected from the light source mounting portion along the direction from the side of the light exit surface to the side of the opposite plate surface, the light source mounting portion may not include the portion having no light source thereon, so that a portion in which an amount of irradiated light from the light source decreases locally is less likely to be generated in the light entrance surface of the light guide plate. Thereby, even if a frame of the lighting device is increasingly narrowed and the light source and the light entrance surface have a closer positional relation, a dark region is less likely to be generated in light output from the light exit surface, thus making it possible to suppress occurrence of luminance unevenness associated with narrowing of the frame. In addition, since the protrusion for power feeding protruding from the light source mounting portion along the direction from the side of the light exit surface to the side of the opposite plate surface, and the power feed portion disposed thereon are exposed to outside through the opening that is formed in the bottom plate portion, so that sufficiently enhanced workability is also achieved when the power feed portion is passed through the opening.

(10) The opening of the bottom plate portion may have an opening edge that is opposite to the light source with respect to the light entrance surface. Thereby, even if a protrusion dimension by which the protrusion for power feeding protrudes from the light source mounting portion is small, a sufficiently large formation range of the opening is ensured so that the opening edge is disposed so as to be opposite to the light source with respect to the light entrance surface, and thus excellent workability is achieved for working of passing the power feed portion through the opening. When the protrusion dimension by which the protrusion for power feeding protrudes from the light source mounting portion is reduced, reduction in thickness of the lighting device is accomplished.

(11) The light guide plate non-support portion may include a recessed portion that is recessed in the bottom plate portion so as to be farther away from the light guide plate, and a deformation portion that is adjacent to the recessed portion in the bottom plate portion, the deformation portion may be away from the opposite plate surface of the light guide plate by a distance that is relatively greater than a distance between the opposite plate surface of the light guide plate support portion and the light guide plate support portion. If the recessed portion that is recessed so as to be farther away from the light guide plate is formed in the bottom plate portion, the deformation portion may be generated by warpage or bending in the bottom plate portion, and such a deformation portion is in a portion of the bottom plate portion adjacent to the recessed portion. Thus, for example, even if the recessed portion is formed not overlapping with the extended reflection portion of the reflection member, the deformation portion may be formed in a portion of the bottom plate portion overlapping with the extended reflection portion of the reflection member. The deformation portion is away from the opposite plate surface of the light guide plate with a distance relatively greater than a distance between the opposite plate surface and the light guide plate support portion. In the reflection member having the cutout portion, a portion of the extended reflection portion is less likely to be separated from the opposite plate surface of the light guide plate due to the deformation portion, which is the light guide plate non-support portion, and light from the light source is less likely to reflect off the extended reflection portion and is less likely to directly enter the opposite plate surface, thus making it possible to effectively suppress luminance unevenness.

(12) The lighting device may further include a board that is opposite to the light guide plate with respect to the bottom plate portion and is attached to the recessed portion. This makes it possible to attach the board, which is provided so as to be opposite to the light guide plate with respect to the bottom plate portion, by using the recessed portion. In other words, even if the deformation portion may be formed in the bottom plate portion according to the formation of the recessed portion in the bottom plate portion in order to attach the board, the reflection member including the cutout portion effectively suppresses luminance unevenness resulting from the deformation portion.

A display device of the invention includes the lighting device above, and a display panel which displays an image by using light from the lighting device. With such a display device, luminance unevenness of the lighting device is suppressed. Thus, the display device of the invention has excellent display quality associated with the image displayed on the display panel and is suitable for an increase in screen size.

A television device of the invention includes the display device above. With such a television device, luminance unevenness of the lighting device included in the display device is suppressed. Thus, the display device of the invention has excellent display quality associated with a television image displayed on the display panel and is suitable for an increase in screen size.

Advantageous Effects of Invention

According to the invention, luminance unevenness is able to be suppressed.

DESCRIPTION OF EMBODIMENTS

Embodiment 1 of the invention will be described with reference toFIG. 1toFIG. 9. In the present embodiment, a liquid crystal display device10will be exemplified. Note that, X-axes, Y-axes and Z-axes are provided in portions of the drawings, respectively, and the axes in each drawing correspond to the respective axes in other drawings. InFIG. 3,FIG. 7andFIG. 8, the upper side and the lower side correspond to the front side and the rear side, respectively.

As illustrated inFIG. 1, a television device TV according to the present embodiment includes the liquid crystal display device10, front and rear cabinets Ca, Cb that hold the liquid crystal display device10therebetween, a power source P, a tuner T, and a stand S. An overall shape of the liquid crystal display device (display device)10is a landscape rectangular, and, as illustrated inFIG. 2, includes at least a liquid crystal panel11which is a display panel, a backlight device (lighting device)12which is a lighting device for supplying illumination light to the liquid crystal panel11, and a first frame13that supports the liquid crystal panel11from the front side and holds the liquid crystal panel11between the first frame13and the backlight device12. Among them, the liquid crystal panel11is attached to the liquid crystal display device10with a posture in which a display screen for displaying an image thereon faces the front side. The first frame13is made of metal (for example, made of aluminum), and is entirely formed in a frame shape extending along an outer peripheral end of the liquid crystal panel11. The first frame13has a first frame main body (frame portion)13awhich extends along the outer peripheral end of the liquid crystal panel11and has a rectangular frame shape in a plan view, and a first frame surrounding portion (cylindrical portion)13bthat is connected to an outer peripheral end of the first frame main body13aand surrounds the backlight device12from an outer peripheral side.

The liquid crystal panel11will be described first. As illustrated inFIG. 2, the liquid crystal panel11includes a pair of glass substrates having a landscape rectangular shape in a plan view and having high light transmission capability. The glass substrates are bonded together with a predetermined gap therebetween. The liquid crystal layer is sealed between the substrates. On one of the substrates (array substrates), switching components (e.g., TFTs) connected to source lines and gate lines that are perpendicular to each other, pixel electrodes connected to the switching components, an alignment film, and the like are provided. On the other substrate, a color filter having color sections such as R (red), G (green) and B (blue) color sections arranged in a predetermined pattern, counter electrodes, an alignment film, and the like are provided. The liquid crystal panel11is sectioned into a display area that is in a center area of a screen and allows display of an image (active area) and a non-display area that is in an outer peripheral end area of the screen and has a frame shape surrounding the periphery of the display area (non-active area). Note that, a pair of front and rear polarizing plates are attached to outer surfaces of the pair of glass substrates.

Next, the backlight device12will be described. As illustrated inFIG. 2andFIG. 3, the backlight device12includes at least a chassis14having a bottom plate portion14a, an LED unit (light source unit) LU including LEDs (Light Emitting Diodes)16that are light sources, a light guide plate19that is placed on the bottom plate portion14aof the chassis14and guides light from the LED unit LU, a reflection sheet (reflection member)20that is arranged between the light guide plate19and the bottom plate portion14a, a second frame21that supports the light guide plate19from the front side and sandwiches and holds the light guide plate19and the reflection sheet20between the chassis14and the second frame21, and an optical sheet (optical member)15that is arranged between the liquid crystal panel11and the light guide plate19. The LED unit LU includes the LEDs16, an LED board (light source board)17on which the LEDs16are mounted, and a heat dissipation member18on which the LED board17is mounted. In the backlight device12, a pair of LED units LU are arranged at one of both long-side edges thereof (on an upper side inFIG. 2, on a right side inFIG. 3), and the LEDs16that are provided on each of the LED units LU are positioned closer to the one long-side edge of the liquid crystal panel11. In this manner, the backlight device12according to the present embodiment is a single edge light type (side light type) in which light enters the light guide plate19through only one surface. The pair of LED units LU are arranged so as to be adjacent to each other along a long-side direction of the light guide plate19. Each component of the backlight device12will be specifically described below.

The chassis14is made of metal, for example, aluminum, and has higher thermal conductivity compared to a chassis made of synthetic resin. As illustrated inFIG. 2andFIG. 3, the chassis14has the bottom plate portion14athat is able to cover substantially overall areas of the light guide plate19and the reflection sheet20from the rear side. The bottom plate portion14ahas a substantially flat plate shape extending along a plate surface of the light guide plate19and is formed in a landscape rectangular shape similarly to the light guide plate19and the reflection sheet20, and has a size in a plan view (a long-side dimension and a short-side dimension) larger than those of the light guide plate19and the reflection sheet20. The bottom plate portion14ahas a posture in which a long-side direction, a short-side direction, and a thickness direction correspond to an X-axis direction, a Y-axis direction, and a Z-axis direction, respectively. Among a pair of long-side outer edges of the bottom plate portion14a, from the outer edge on the LED unit LU side (the upper side inFIG. 2, the right side inFIG. 3), a first side plate portion14bis provided so as to extend to the rear side along the Z-axis direction, and from the outer edge on the opposite side to the LED unit LU side (a lower side inFIG. 2, a left side inFIG. 3), a second side plate portion14cis provided so as to upstand to the front side (opposite side to that of the first side plate portion14b) along the Z-axis direction. Each of the first side plate portion14band the second side plate portion14cis bent substantially at right angle from each long-side outer edge of the bottom plate portion14a, and has a plate surface orthogonal to the plate surface of the bottom plate portion14aand in parallel to the long-side direction (X-axis direction) of the bottom plate portion14a. Further, since the first side plate portion14band the second side plate portion14care arranged so as to extend an almost full length (as to the first side plate portion14b, excluding a chassis-side opening28, which will described below) along the long-side direction in the bottom plate portion14a, mechanical strength of the bottom plate portion14amay be increased, in particular, deformation such as bending or warpage along a short-side direction is less likely to be caused in the bottom plate portion14a.

As illustrated inFIG. 2andFIG. 3, optical sheets15have a landscape rectangular shape in a plan view similarly to the liquid crystal panel11, and have a size in a plan view (a short-side dimension and a long-side dimension) slightly smaller than that of the liquid crystal panel11. The optical sheets15are arranged so as to be positioned between the liquid crystal panel11and the light guide plate19to thereby transmit light output from the light guide plate19and output the transmission light to the liquid crystal panel11while applying predetermined optical actions thereto. The optical sheets15have a sheet shape whose thickness is thinner than that of the light guide plate19and form a group of the optical sheets15by laminating a plurality of sheets (two sheets in the present embodiment) with almost no gap therebetween, and the group of the optical sheets15is positioned with a predetermined space from each of a rear-side plate surface of the liquid crystal panel11and a front-side plate surface of the light guide plate19(light exit surface19a). Examples of a specific type of the optical sheets15include a diffuser sheet, a lens sheet, and a reflecting type polarizing sheet, and the optical sheets may be selected appropriately therefrom for usage.

Next, configurations of the LEDs16, the LED boards17, and the heat dissipation members18, which form the LED units LU, will be described. As illustrated inFIG. 2andFIG. 3, each of the LEDs16is configured so as to seal an LED chip with a resin material on a board portion fixed to the LED board17. The LED chip mounted on the board portion has one main light emission wavelength, and specifically, the LED chip that emits light in a single color of blue is used. On the other hand, the resin material that seals the LED chip contains phosphors dispersed therein, and the phosphors emit light in a predetermined color when excited by blue light emitted from the LED chip. The phosphors may be selected as appropriate from yellow phosphors that emit yellow light, green phosphors that emit green light, and red phosphors that emit red light, to be used in combination, or one of them may be used alone. Each of the LEDs16is in a so-called top-surface-emitting type in which a surface opposite to a mounting surface on the LED board17serves as a main light-emitting surface16a. The main light-emitting surface16aof the LED16has a substantially rectangular shape which is landscape in a front view (long and narrow along the X-axis direction) (refer toFIG. 8), and has a short-side dimension which is the same as or slightly smaller than a dimension of plate thickness of the light guide plate19.

One LED board17is provided on each of the pair of LED units LU as illustrated inFIG. 2andFIG. 3. The LED board17has a long and narrow plate shape that entirely extends along a long-side direction of the chassis14(the X-axis direction, a longitudinal direction of a light entrance surface19bin the light guide plate19), and is attached to the heat dissipation member18and housed in the backlight device12with a posture in which a plate surface thereof is in parallel to the X-axis direction and the Z-axis direction, that is, a posture in which the plate surface is orthogonal to the plate surfaces of the liquid crystal panel11and the light guide plate19(optical sheets15). The LED board17is attached so that a plate surface opposite to the mounting surface on which the LEDs16are mounted is in contact with the heat dissipation member18and is arranged on the right side inFIG. 3with a predetermined arrangement distance from the long-side edge (light entrance surface19b) of the light guide plate19. Accordingly, the direction in which the LEDs16and the LED board17are arrayed in line with the light guide plate19almost corresponds to the Y-axis direction, and an optical axis in each of the LEDs16, that is, an advancing direction of light that has the highest light emission intensity almost corresponds to the Y-axis direction (direction in parallel to the plate surface of the liquid crystal panel11).

Specifically, as illustrated inFIG. 2andFIG. 3, the LED board17has an LED mounting portion (light source mounting portion)17awhich extends along the X-axis direction and on which a plurality of LEDs16are mounted, and a protrusion for power feeding17b. The protrusion for power feeding17bprotrudes toward the rear side from the LED mounting portion17aalong the Z-axis direction and includes a board-side connector (power feed portion)22used for feeding power to the LEDs16. The LED mounting portion17ahas a posture in which a long-side direction (length direction) and a short-side direction (width direction) thereof correspond to the X-axis direction and the Z-axis direction, respectively, and further, a plate thickness direction orthogonal to the plate surface corresponds to the Y-axis direction, and while a length dimension of the LED mounting portion17ais about a half of the long-side dimension of the light guide plate19, a width dimension thereof is slightly larger than a dimension of the plate thickness of the light guide plate19. In the LED mounting portion17a, an inner side thereof, that is, a plate surface facing the light guide plate19side (surface opposite to the light guide plate19) is a mounting surface on which the LEDs16are surface-mounted. A plurality of LEDs16are arranged in a row (linearly) along the length direction (X-axis direction) on the mounting surface of the LED mounting portion17aat a predetermined arrangement interval. That is, it may be said that the plurality of LEDs16are arranged intermittently along the long-side direction at one long-side edge of the back light device12. Accordingly, a direction in which the LEDs16are arranged matches the length directions (X-axis direction) of the LED board17and the light guide plate19. Intervals between the adjacent LEDs16in the X-axis direction which is the direction in which the LEDs16are arranged, that is, array intervals (array pitches) of the LEDs16are almost equal. A wiring pattern (not illustrated) that is made of a metal film (copper foil or the like) and extends along the X-axis direction is connected to terminals of the respective LEDs16is formed on the mounting surface of the LED mounting portion17a.

As illustrated inFIG. 7andFIG. 8, the protrusion for power feeding17bis provided so as to be in continuous to a center portion of the LED mounting portion17ain a length direction and protrudes along a direction extending from the LED mounting portion17ato a bottom wall portion18a2of the heat dissipation member18described below (a direction extending from the light exit surface19ato an opposite plate surface19cin the light guide plate19). That is, the LED board17has a substantially T-shape in a front view. The protrusion for power feeding17bhas a landscape rectangular shape in a front view, and has a posture in which a long-side direction and a short-side direction (direction of protruding from the LED mounting portion17a) correspond to the X-axis direction and the Z-axis direction, respectively, and further, a plate thickness direction orthogonal to the plate surface corresponds to the Y-axis direction, and a length dimension of the LED protrusion for power feeding17bis sufficiently smaller than that of the LED mounting portion17a. The protrusion for power feeding17bhas a plate surface facing an inner side thereof, that is, a plate surface on the same side as the mounting surface in the LED mounting portion17a, and the plate surface is a mounting surface on which the board-side connector22is surface-mounted. On the mounting surface of the protrusion for power feeding17b, the wiring pattern formed on the mounting surface of the LED mounting portion17ais formed continuously and the board-side connector22is mounted being positioned at an end of the wiring pattern. The board-side connector22includes a board-side housing22athat is made of synthetic resin and has a substantially cylindrical shape having one end (right side inFIG. 8) in the X-axis direction being opened, and a board-side terminal fitting (not illustrated) that is housed in the board-side housing22aand connected to the end of the wiring pattern. A wiring-side connector (power feed portion)23that is provided at an end of a wiring member24connected to an LED driving circuit board, which is not illustrated, is able to be connected to the board-side connector22by fitting with each other, and a fitting direction thereof corresponds to the X-axis direction. Specifically, the wiring-side connector23, when being connected, is fitted with the board-side connector22from the right side to the left side inFIG. 8along the X-axis direction, and, when being disconnected, the wiring-side connector23is removed from the board-side connector22, to the contrary, from the left side to the right side inFIG. 8along the X-axis direction. When the wiring-side connector23is connected to the board-side connector22by fitting with each other in this manner, power from the LED driving circuit board is able to be supplied to each of the LEDs16. The wiring-side connector23that is connected to the board-side connector22by fitting with each other includes a wiring-side housing23athat has a substantially block shape with the X-axis direction as a length direction and is made of synthetic resin, and a wiring-side terminal fitting (not illustrated) that is housed in the wiring-side housing23aand connected to an end of the wiring member24. Note that, a base member of the LED board17is made of metal, for example, such as aluminum, has the wiring pattern described above formed on the surface of the base member through an insulating layer. Note that, an insulating material such as synthetic resin or ceramic is also able to be used as the material used for the base member of the LED board17.

The wiring pattern of the LED board17will be described in detail. That is, a group of the LEDs16mounted on the LED mounting portion17aof the LED board17according to the present embodiment is divided into right and left two groups illustrated inFIG. 8in a parallel direction thereof (X-axis direction) and is connected to two lines of wiring patterns which run according to each of the groups. This makes is possible to reduce a voltage value required for driving the group of the LEDs16included in each group, compared to a case where the number of lines is set as one. To describe specific running routes of the wiring patterns, each of the two lines of wiring patterns sets an end connected to the board-side connector22as a start point, and from the start point, runs so as to be separated to one side and the other side of the length direction of the LED mounting portion17afrom a center portion of the LED mounting portion17ain the length direction, which is continuous to the protrusion for power feeding17b, so that the LEDs16that are included in each of the groups are connected in parallel. The protrusion for power feeding17bis configured to be continuous to the center portion of the LED mounting portion17awith respect to the length direction, and the two lines of wiring patterns run so as to be branched into the two sides from the center portion of the LED mounting portion17awith respect to the length direction (X-axis direction). Accordingly, each of the wiring patterns is prevented from being arrayed along a width direction (Z-axis direction) of the LED mounting portion17a, thus making it possible to reduce a width dimension of the LED mounting portion17a. This makes it possible to reduce thickness of the backlight device12and the liquid crystal display device10.

The heat dissipation members18are made of metal having high thermal conductivity, for example, such as aluminum, and are provided by each one in the pair of LED units LU as illustrated inFIG. 3andFIG. 4. The heat dissipation member18entirely extends along the long-side direction of the light guide plate19and has a length dimension that is almost same as the length dimension of the LED board17and is about a half of the long-side dimension of the light guide plate19. The heat dissipation member18is attached to one long-side end of the chassis14and is arranged so as to be exposed to an outside of the backlight device12, and is thereby allowed to promote heat dissipation of heat from the LEDs16by transferring heat transferred from the LEDs16via the LED board17to the bottom plate portion14aof the chassis14or to the outside air which exists outside the backlight device12.

As illustrated inFIG. 3, the heat dissipation member18includes a board housing portion18ain which the LED board17is housed, and a chassis-side heat dissipation portion18bwhich extends so as to be closer to the bottom plate portion14aof the chassis14than the board housing portion18aand makes contact with the bottom plate portion14a. Among them, the board housing portion18aincludes a board attachment portion18a1to which the LED board17is attached, the bottom wall portion18a2that protrudes to the chassis14side from a rear-side end of the board attachment portion18a1, and a side wall portion18a3that upstands from the end protruding from the board attachment portion18a1in the bottom wall portion18a2to the front side and faces the board attachment portion18a1with a predetermined interval therebetween. The LED board17is housed in a space formed between the board attachment portion18a1and the side wall portion18a3which form the board housing portion18a, and is attached to the board attachment portion18a1. The board attachment portion18a1has a plate surface having a plate shape in parallel to the plate surface of the LED board17, and a length direction, a width direction, and a plate thickness direction thereof correspond to the X-axis direction, the Z-axis direction, and the Y-axis direction, respectively. The bottom wall portion18a2is bent substantially at right angle from the board attachment portion18a1and has a plate surface formed in a plate shape in parallel to the plate surface of the bottom plate portion14aof the chassis14. The side wall portion18a3is bent substantially at right angle from the bottom wall portion18a2and has a plate surface formed in a plate shape in parallel to each plate surface of the board attachment portion18a1and the LED board17. A width dimension of the side wall portion18a3(stand-up dimension from the bottom wall portion18a2) is smaller than a width dimension of the board attachment portion18a1. The first side plate portion14bof the chassis14is housed in a space formed between the side wall portion18a3and the LED board17, and a plate surface of the first side plate portion14b, which is opposite to the LED board17, is arranged so as to be in contact with or proximate to the side wall portion18a3.

As illustrated inFIG. 3, the chassis-side heat dissipation portion18bhas a plate surface formed in a plate shape in parallel to plate surfaces of the bottom plate portion14aof the chassis14and the bottom wall portion18a2, and a length direction, a width direction, and a plate thickness direction thereof correspond to the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively. A width dimension of the chassis-side heat dissipation portion18b(protruding dimension from the side wall portion18a) is larger than each width dimension of the bottom wall portion18a2and the side wall portion18a3. Further, the chassis-side heat dissipation portion18bcovers one long-side end of the bottom plate portion14aof the chassis14from the rear side and has a plate surface on the front side thereof made in surface-contact with the rear-side plate surface of the bottom plate portion14aover a substantially overall area, and is therefore able to efficiently transfer heat, which is transferred from the LEDs16through the LED board17and the board housing portion18a, to the bottom plate portion14a, thus making it possible to promote heat dissipation of the LEDs16. In addition, since the overall area of the chassis-side heat dissipation portion18bis exposed to an outside on the rear side of the backlight device12and a large part of the board housing portion18a(part excluding a part of the board attachment portion18a1) is exposed to the outside on the rear side of the backlight device12, they are air-cooled with the outside air, thus making it possible to further promote heat dissipation of the LEDs16.

The light guide plate19is made of a substantially transparent (high light transmissivity) synthetic resin material (e.g. acrylic resin or polycarbonate such as PMMA) which has a refractive index sufficiently higher than that of the air. As illustrated inFIG. 2andFIG. 3, the light guide plate19has a landscape rectangular shape in a plan view similarly to the liquid crystal panel11and the optical sheet15, and a long-side direction and a short-side direction in the plate surface thereof correspond to the X-axis direction and the Y-axis direction, respectively, and a plate thickness direction that is perpendicular to the plate surface corresponds to the Z-axis direction. The light guide plate19is disposed on the rear side of the optical sheet15with a predetermined interval so as to face with each other. The light guide plate19is positioned behind the liquid crystal panel11and the optical sheet15in the chassis14, and one long-side end surface among outer peripheral end surfaces thereof faces the LEDs16of the LED unit LU. Accordingly, the direction in which the LEDs16(LED board17) and the light guide plate19are arranged corresponds to the Y-axis direction, while a direction in which the optical sheet15(liquid crystal panel11) and the light guide plate19are arranged corresponds to the Z-axis direction, and both of the arrangement directions are perpendicular to each other. The light guide plate19has a function of guiding light, which is emitted from the LEDs16along the Y-axis direction, from the long-side end surface and outputting the light from the plate surface by setting it up to be directed toward the optical sheet15side (front side, light exit side) while propagating the light inside thereof.

As illustrated inFIG. 3, one plate surface facing the front side (a surface facing the optical sheet15) among a pair of front and rear plate surfaces of the light guide plate19is the light exit surface19athrough which the inside light exits toward the optical sheet15and the liquid crystal panel11. Among a pair of long-side end surfaces having elongated shapes along the X-axis direction (the direction in which the LEDs16are arranged, the long-side direction of the LED board17) of outer peripheral end surfaces adjacent to the plate surface of the light guide plate19, one end surface (on the upper side inFIG. 2, on the right side inFIG. 3) faces the LEDs16(LED board17) with a predetermined space and serves as the light entrance surface19bthat the light emitted from the LEDs16enters. With such a gap between the light entrance surface19band the LEDs16, it is possible to prevent a situation that the light entrance surface19binterferes the LEDs16when the light guide plate19causes thermal expansion by heat from the LEDs16or the like. Distances between the light entrance surface19band the respective facing LEDs16are substantially the same. It. may be also said that the light entrance surface19bforms an “end surface facing LEDs (end surface facing light sources)” because of facing the LEDs16. On the other hand, among outer peripheral surfaces adjacent to the plate surface of the light guide plate19, each of other three end surfaces excluding the light entrance surface19bdescribed above (a long-side end surface opposite to the light entrance surface19b, and a pair of short-side both end surfaces) is an end surface not facing LEDs (end surface not facing light sources), which does not face the LEDs16. The light entrance surface19bis a surface in parallel to the X-axis direction (the direction in which the LEDs16are arranged) and the Z-axis direction, that is, the plate surface of the LED board17, and is a surface which is almost perpendicular to the light exit surface19a. A direction in which the LEDs16and the light entrance surface19bare arranged matches the Y-axis direction and is in parallel to the light exit surface19a.

As illustrated inFIG. 3, the reflection sheet20is disposed so as to cover the rear side of the light guide plate19, that is, the opposite plate surface19copposite to the light exit surface19a(a surface facing the bottom plate portion14aof the chassis14), and is allowed to reflect light, that exits toward the outside of the rear side through the opposite plate surface19c, and set up the light toward the front side. In other words, the reflection sheet20is disposed so as to be sandwiched between the bottom plate portion14aof the chassis14and the light guide plate19. The reflection sheet20has a slightly larger size in a plan view than that of the light guide plate19, and is able to cover the opposite plate surface19cof the light guide plate19over an almost overall area (in detail, a large part of a portion overlapping with a light guide plate non-support portion30described below, excluding a part of the portion). The reflection sheet20has a slightly larger size (a long-side dimension and a short-side dimension) in a plan view than that of the light guide plate19. In particular, an end of the reflection sheet20on the light entrance surface19bside of the light guide plate19(one long-side end) is an extended reflection portion20awhich extends outward from the light entrance surface19b, that is, toward the LEDs16side. The extended reflection portion20ais provided so as to extend over an almost full length of the reflection sheet20in a long-side direction (X-axis direction) thereof and, in other words, is arranged across LED arranged areas in which the LEDs16are arranged and LED non-arranged areas in which no LED16is arranged, in the direction in which the LEDs16are arranged. By reflecting light which exists in a space formed between the LED board17and the light entrance surface19btoward the front side, the extended reflection portion20aachieves high light entering efficiency for the light entrance surface19b. The light which is reflected by the extended reflection portion20aand enters the light entrance surface19bis reflected totally by the light exit surface19aand propagated through the light guide plate19toward a direction away from the LEDs16(refer to a light path represented by a long dashed short dashed line inFIG. 3), because even if being directed to the light exit surface19adirectly, an incidence angle on the light exit surface19aexceeds a critical angle. A light reflection pattern (not illustrated) formed of a light reflection portion for reflecting light in the light guide plate19toward the light exit surface19ato thereby exit the light from the light exit surface19ais formed in the opposite plate surface19cof the light guide plate19. The light reflection portion forming the light reflection pattern includes a large number of dots which are formed by printing a light reflective material (for example, ink having a white color, which contains metallic oxide such as titanium oxide) on the opposite plate surface19cof the light guide plate19, and the light reflection pattern is formed with such a distribution that a distribution density of the dots (an area ratio per a unit area in the opposite plate surface19c) increases as being closer from the end of the light guide plate19on the light entrance surface19bside to the end on the opposite side in the Y-axis direction.

The second frame21is made of synthetic resin and is entirely formed, as illustrated inFIG. 2andFIG. 3, in a frame shape extending along the outer peripheral end of the liquid crystal panel11. The second frame21has a second frame main body (frame portion)21awhich extends along the outer peripheral end of the light guide plate19and has a rectangular frame shape in a plan view, and a second frame surrounding portion (cylindrical portion)21bwhich runs with an outer peripheral end of the second frame main body21aand surrounds the chassis14and the heat dissipation member18attached thereto from an outer peripheral side. The second frame main body21ais disposed facing the front side of the outer peripheral end of the light guide plate19, and is able to support an almost whole circumference of the outer peripheral end of the light guide plate19from the front side. On the rear side of the second frame main body21a, that is, a surface facing the light guide plate19, a cushion material for the light guide plate25is provided so as to be positioned between the rear side of the second frame main body21aand the outer peripheral end of the light guide plate19, thus making it possible to achieve cushioning for the light guide plate19. One long side portion of the second frame main body21a, which faces the LED unit LU, is disposed so as to cover a space formed between the LED unit LU and the light guide plate19from the front side over a substantially overall area and has the cushion material for the light guide plate25so as to be positioned between the second frame main body21aand the one long side portion of the light guide plate19, in which the light entrance surface19bis provided, and therefore able to block light which is emitted from the LEDs16and directed toward the front side and prevent the light leakage caused by the light directly entering the optical sheet15and the liquid crystal panel11without passing through the light guide plate19.

As illustrated inFIG. 3, the second frame main body21ahas a substantially three-step shape in a cross-sectional shape, in which a first step portion21a1on the top supports the first frame main body13aof the first frame13from the rear side, a second step portion21a2at a middle height supports the outer peripheral end of the liquid crystal panel11from the rear side, and a third step portion21a3on the bottom supports the outer peripheral end of the optical sheet15from the rear side. Among them, on a front side of the second step portion21a2, that is, a surface on the side facing the liquid crystal panel11, a cushion material for the liquid crystal panel26is provided so as to be positioned between the front side of the second step portion21a2and the outer peripheral end of the liquid crystal panel11, thus making it possible to achieve cushioning for the liquid crystal panel11. On a front side of the third step portion21a3, that is, a surface on the side facing the optical sheet15, a cushion material for the optical sheet27is provided so as to be positioned between the front side of the third step portion21a3and the outer peripheral end of the optical sheet15, thus making it possible to achieve cushioning for the optical sheet15.

In the backlight device12configured as described above, as illustrated inFIG. 5,FIG. 7andFIG. 8, in order to insert, from outside, the wiring-side connector23which is connected to the board-side connector22of the LED board17by fitting with each other, a chassis-side opening28and a heat dissipation member-side opening29are respectively formed in the chassis14and the heat dissipation member18so as to communicate with each other and be opened facing the rear side. The chassis-side opening28and the heat dissipation member-side opening29are able to cause the board-side connector22and the wiring-side connector23which are connected by fitting with each other in the backlight device12to be exposed to the outside of the rear side. The chassis-side opening28and the heat dissipation member-side opening29are disposed at positions overlapping with the board-side connector22and the wiring-side connector23in a plan view. On the other hand, one set of the board-side connector22and the wiring-side connector23is provided in each LED unit LU so that two sets of them are provided in total. Accordingly, each one set of the chassis-side opening28and the heat dissipation member-side opening29is arranged at a substantially middle position between a center position and each of positions of both ends in the chassis14in the X-axis direction. Moreover, the chassis-side opening28and the heat dissipation member-side opening29are disposed at an end of the chassis14in the Y-axis direction, which is on the LED unit LU side.

Among them, the chassis-side opening28is formed by cutting out a part of portions of the bottom plate portion14aand the first side plate portion14bof the chassis14, which overlap with the heat dissipation member18and each of the connectors22and23in a plan view (when viewed from a normal direction with respect to the plate surface of the bottom plate portion14a) and has a rectangular shape in a plan view, as illustrated inFIG. 5,FIG. 7andFIG. 8. Specifically, as illustrated inFIG. 7, the chassis-side opening28is formed in a range across the long-side portion of the bottom plate portion14ain the Y-axis direction, which is on the LED unit LU side, and the first side plate portion14b, to thereby open to the front and rear sides along the Z-axis direction and also to the LED unit LU side along the Y-axis direction. The chassis-side opening28is disposed so that an opening edge in the Y-axis direction is recessed so as to be farther away from the LEDs16with respect to the light entrance surface19bof the light guide plate19. As illustrated inFIG. 8, the chassis-side opening28is formed in a wider range than that of the protrusion for power feeding17bof the LED board17in the X-axis direction, and, specifically, formed so that an overall area in the X-axis direction in a front view of the protrusion for power feeding17band the board-side connector22(when viewed from a normal direction with respect to the plate surface of the LED board17) overlaps with the protrusion for power feeding17band the board-side connector22and the protrusion for power feeding17band the board-side connector22are positioned being closer to the left inFIG. 8(closer to an end opposite to a direction in which the board-side connector22opens). In other words, the chassis-side opening28is formed so that the opening edge on the right side inFIG. 8in the X-axis direction is disposed at a position between the protrusion for power feeding17band the board-side connector22with a fixed interval (interval to an extent that the wiring-side connector23described below is allowed to be arranged). It may be said that a portion of the bottom plate portion14aof the chassis14, in which the chassis-side opening28is formed, forms the light guide plate non-support portion30which is not able to support the light guide plate19and the reflection sheet20from the rear side. In other words, an opening non-forming portion in which the chassis-side opening28is not formed (substantially overall area excluding the chassis-side opening28) in the bottom plate portion14aof the chassis14forms a light guide plate support portion31which is able to support the light guide plate19and the reflection sheet20from the rear side.

The heat dissipation member-side opening29is a through hole and has a rectangular shape in a plan view, as illustrated inFIG. 5,FIG. 7andFIG. 8. A part of portions of the bottom wall portion18a2, the side wall portion18a3and the chassis-side heat dissipation portion18bof the heat dissipation member18overlapping with the chassis14and each of the connectors22and23in a plan view is inserted in the heat dissipation member-side opening29. Specifically, as illustrated inFIG. 7, the heat dissipation member-side opening29is formed in a range extending from the bottom wall portion18a2of the heat dissipation member18to the chassis-side heat dissipation portion18bin the Y-axis direction, and an outside opening edge thereof is substantially flush with the mounting surface of the LED board17, while an inside opening edge thereof is disposed so as to be recessed to be farther away from the LEDs16with respect to the light entrance surface19bof the light guide plate19and is flush with an inside opening edge of the chassis-side opening28. The heat dissipation member-side opening29is formed in a wider range than that of the protrusion for power feeding17bof the LED board17in the X-axis direction, and has an opening edge which is substantially flush with the inside opening edge of the chassis-side opening28. Accordingly, the heat dissipation member-side opening29is formed so that an overall area in the X-axis direction in a front view of the protrusion for power feeding17band the board-side connector22overlaps with the protrusion for power feeding17band the board-side connector22and the protrusion for power feeding17band the board-side connector22are positioned being closer to the left inFIG. 8. In other words, the chassis-side opening28is formed so that the opening edge on the right side inFIG. 8in the X-axis direction is disposed at a position between the protrusion for power feeding17band the board-side connector22with a fixed interval. The heat dissipation member-side opening29is formed in the hole shape as described above, so that an opening edge thereof has an endless ring shape.

By setting a formation range of the chassis-side opening28and the heat dissipation member-side opening29in a plan view (a formation range in the X-axis direction and the Y-axis direction) as described above, it is possible to ensure an arrangement space in which the wiring-side connector23before being fitted to the board-side connector22is arranged in the X-axis direction (space for fitting work) as illustrated inFIG. 8, and to allow a finger of an operator to enter the chassis-side opening28and the heat dissipation member-side opening29when inserting the wiring-side connector23into the chassis-side opening28and the heat dissipation member-side opening29in the Y-axis direction as illustrated inFIG. 7. In this case, if a protrusion for power feeding in an LED board is formed so as to protrude to the outside on the rear side of the heat dissipation member18, the formation range of the chassis-side opening28and the heat dissipation member-side opening29is able to be reduced. However, a problem is thereby caused that thickness (dimension in the Z-axis direction) of the backlight device and the liquid crystal display device increases by an amount of protrusion of the protrusion for power feeding to the outside on the rear side of the heat dissipation member18. Thus, for decreasing thickness of the backlight device12and the liquid crystal display device10, it is useful to expand the formation range of the chassis-side opening28and the heat dissipation member-side opening29in a plan view compared to the arrangement range of the board-side connector22and the wiring-side connector23which are being fitted to each other.

Meanwhile, the chassis-side opening28as described above is formed in the bottom plate portion14aof the chassis14, and the portion of the bottom plate portion14ahaving the chassis-side opening28is the light guide plate non-support portion30that is not able to support the light guide plate19. Therefore, a portion of the reflection sheet20that is disposed between the light guide plate19and the bottom plate portion14aand overlaps with the light guide plate non-support portion30may be deformed so as to be away from the opposite plate surface19cof the light guide plate19. In particular, in order to cause the board-side connector22and the wiring-side connector23on the LED board17to be exposed to the outside and allow work for fitting the wiring-side connector23, the chassis-side opening28, which is the light guide plate non-support portion30, is formed in a range extending from the mounting surface of the LEDs16on the LED board17to a position opposite to the LEDs16with respect to the light entrance surface19bin the Y-axis direction, and as a result thereof, disposed so as to overlap with a part of the extended reflection portion20ain a plan view, in addition to a part of a main body part of the reflection sheet20(a part excluding the extended reflection portion20a). Therefore, as illustrated in a comparative example ofFIG. 9, if a portion of the reflection sheet20overlapping with the chassis-side opening28, which is the light guide plate non-support portion30(including the extended reflection portion20a), is deformed so as to be away from the opposite plate surface19cof the light guide plate19, light from the LEDs16is reflected particularly by the extended reflection portion20aof the separated portion. Accordingly, the reflection light enters the light guide plate19from the rear side thereof (through a gap between the light guide plate19and the separated portion of the reflection sheet20) and easily enters the light guide plate19through the opposite plate surface19c(refer to a light path represented by a long dashed short dashed line inFIG. 9). If the light directly incident on the opposite plate surface19cfrom the rear side of the light guide plate19without passing through the light entrance surface19bin this manner travels within the light guide plate19toward the light exit surface19a, an incidence angle on the light exit surface19adoes not exceed a critical angle. Therefore, the light directly exits the light guide plate19through the light exit surface19a(refer to the light path represented by a long dashed short dashed line inFIG. 9), and a bright region is may be locally generated on the light exit surface19aand may be visually recognized as luminance unevenness by a user (observer) of the backlight device12and the liquid crystal display device10. Note that,FIG. 9is a cross-sectional view of the liquid crystal display device10according to the comparative example in which the reflection sheet20in which the “cutout portion32” as a characteristic structure described below according to the present embodiment is not formed is included, and the same reference signs as those of other figures (FIG. 1toFIG. 8) according to the present embodiment are described inFIG. 9for convenience of description.

Thus, in the present embodiment, the cutout portion32is formed by cutting out at least a part of a portion of the extended reflection portion20aoverlapping with the chassis-side opening28, which is the light guide plate non-support portion30, in a plan view (when viewed from a normal direction with respect to the light exit surface19a), as illustrated inFIG. 6andFIG. 7. By forming such a cutout portion32in the reflection sheet20, a portion of the extended reflection portion20ais less likely to be separated from the opposite plate surface19cof the light guide plate19due to the chassis-side opening28, which is the light guide plate non-support portion30, and it is hardly occurred that light from the LEDs16is reflected by the extended reflection portion20aand directly enters the light guide plate19through the opposite plate surface19c. Thereby, the light entering the light guide plate19through the opposite plate surface19cis less likely to directly exit from the light guide plate19through the light exit surface19adirectly. Therefore, a bright region is less likely to be generated locally on the light exit surface19aand luminance unevenness is less likely to be caused in the light from the light exit surface19a.

Specifically, the reflection sheet20is formed, as illustrated inFIG. 6, so that an opening size of the cutout portion32in the X-axis direction changes according to a position in the Y-axis direction and continuously decreases as being farther away from the LEDs16and, to the contrary, continuously increases as being closer to the LEDs16. In other words, the cutout portion32is formed so that a distance from a cutout edge thereof to the LEDs16in the Y-axis direction continuously increases as being closer to a center of the cutout portion32in the X-axis direction and, to the contrary, continuously decreases as being closer to both end sides of the cutout portion32in the X-axis direction. That is, an overall shape of the cutout portion32is triangular in a plan view and has a pair of cutout edges having an inclined shape. Each of the cutout edges is inclined with respect to both of the X-axis direction and the Y-axis direction and the pair cutout edges is a pair of inclined portions33. The pair of inclined portions33has a symmetrical shape and has a substantially V-shape, so that a plan shape of the cutout portion32is an isosceles triangle shape. In the reflection sheet20having the cutout portion32, an amount of reflection light locally decreases in the cutout portion32, so that an amount of light output through the light exit surface19aof the light guide plate19may locally decrease and cause a dark region locally, and a great difference of luminance may be caused between the bright region and the dark region and visually recognized as luminance unevenness. As described before, in the reflection sheet20including the cutout portion32having the inclined portions33as the cutout edges, an area of the reflection sheet20, that is, an amount of reflection light reflecting off the reflection sheet20continuously changes in the X-axis direction. Therefore, compared to a configuration that a dimension of the cutout portion in the X-axis direction is constant or decreases in a stepwise manner as being farther away from the LEDs16, a dark region that may be caused in the light exit surface19aof the light guide plate19by forming of the cutout portion32is less likely to be visually recognized. This is more suitable for suppressing occurrence of luminance unevenness. Note that, in each of the inclined portions33which are cutout edges of the cutout portion32, an intermediate portion intersects the light entrance surface19bof the light guide plate19in a plan view, and the intersect part is disposed outside the chassis-side opening28(light guide plate non-support portion30) in the X-axis direction and arranged without overlapping.

Both ends of the cutout portion32in the X-axis direction, as illustrated inFIG. 6, or one ends of the respective inclined portions33in the X-axis direction are continuous to the outer edge of the extended reflection portion20ain the Y-axis direction at an obtuse angle, while another ends of the respective inclined portions33in the X-axis direction are continuous to each other at an obtuse angle in a center portion of the cutout portion32in the X-axis direction. As illustrated inFIG. 6andFIG. 7, the center portion of the cutout portion32in the X-axis direction (the other ends of both inclined portions33in the X-axis direction) has the cutout edge that is farthest from the LEDs16and is recessed so as to be farther away from the LEDs16with respect to the light entrance surface19bof the light guide plate19in the Y-axis direction. That is, the cutout portion32is formed in an area in the extended reflection portion20aand in a main body part of the reflection sheet20in the Y-axis direction. With such a configuration, compared to a configuration that the cutout edge of the cutout portion is closer to the LEDs16than the light entrance surface19b, a portion of the extended reflection portion20ais less likely to be separated from the opposite plate surface19cof the light guide plate19due to the chassis-side opening28that is the light guide plate non-support portion30, and light from the LEDs16is less likely to reflect off the extended reflection portion20aand directly enters the light guide plate19through the opposite plate surface19c. Accordingly, luminance unevenness is suppressed more suitably. Further, compared to a configuration that the cutout edge of the cutout portion is flush with the light entrance surface19b, the inclined portions33, which are the cutout edges, are less likely to be closer to the LEDs16than the light entrance surface19b, even if the inclined portions33, which are the cutout edges of the cutout portion32, are arranged with positional errors because of tolerance of a dimension, tolerance of attachment or the like. Accordingly, occurrence of luminance unevenness is suppressed more suitably. In addition, since the cutout portion32is formed so that the other ends of the respective inclined portions33in the X-axis direction are disposed closer to the LEDs16than the edge of the chassis-side opening28, which is the light guide plate non-support portion30, in the Y-axis direction, reflection light reflecting off the reflection sheet20is sufficiently secured and use efficiency of light is less likely to be lowered, compared to a configuration that the cutout edge of the cutout portion is flush with the edge of the chassis-side opening28, which is the light guide plate non-support portion30, and an amount of reflection light reflecting off the reflection sheet20decreases so that use efficiency of light is lowered. Note that, when the cutout edge of the cutout portion32is disposed closer to the light entrance surface19bthan the edge of the chassis-side opening28, which is the light guide plate non-support portion30, a portion of the extended reflection portion20amay be separated from the opposite plate surface19cof the light guide plate19due to the chassis-side opening28, which is the light guide plate non-support portion30. However, the cutout edge of the cutout portion32is flush with the light entrance surface19bor opposite to the LEDs16side with respect to the light entrance surface19b. Accordingly, reflection light reflecting off the extended reflection portion20athat extends so as to be closer to the LEDs16than the light entrance surface19bis less likely to directly enter the light guide plate19through the opposite plate surface19c, so that luminance unevenness is hard to be generated surely.

Moreover, the reflection sheet20is formed so as to have a formation range of the cutout portion32in the X-axis direction (direction along the light entrance surface19b) greater than a formation range of the chassis-side opening28, which is the light guide plate non-support portion30, in the X-axis direction, and the cutout portion32overlaps with the light guide plate support portion31in the X-axis direction. Therefore, an amount of reflection light changes continuously between the portion of the extended reflection portion20aoverlapping with the chassis-side opening28, which is the light guide plate non-support portion30, and the portion of the extended reflection portion20aoverlapping with the light guide plate support portion31. Thereby, a dark region that may be generated in the light exit surface19aof the light guide plate19due to the forming of the cutout portion32is hard to be visually recognized, and it is further suitable for suppressing occurrence of luminance unevenness. Even if the cutout portion32is formed with positional errors, for example, because of an influence of tolerance of a dimension, tolerance of attachment, or the like, the cutout portion32is likely to be disposed so as to appropriately overlap with the chassis-side opening28, which is the light guide plate non-support portion30, in the X-axis direction, so that an effect of suppressing luminance unevenness by the cutout portion32is achieved more reliably. Note that, the cutout portion32is formed so that the cutout edge is recessed so as to be farther away from the LEDs16with respect to the light entrance surface19bat a part adjacent to an overlapping portion with the chassis-side opening28, which is the light guide plate non-support portion30, among an overlapping portion with the light guide support portion31in the extended reflection portion20a, and the cutout edge is closer to the LEDs16than the light entrance surface19bat the remaining part. Further, the reflection sheet20is formed so as to have a formation range of the cutout portion32in the X-axis direction (largest dimension) greater than a formation range of the cutout portion32in the Y-axis direction (direction from the LEDs16to the light entrance surface19b) (largest dimension). Therefore, even if the cutout portion32is disposed with positional errors in the X-axis direction, for example, because of an influence of tolerance of a dimension, tolerance of attachment, or the like, the cutout portion32is likely to be disposed so as to appropriately overlap with the chassis-side opening28, which is the light guide plate non-support portion30, in the X-axis direction, thus an effect of suppressing luminance unevenness by the cutout portion32is achieved more reliably. If the formation range of the cutout portion in the Y-axis direction is greater than or same as the formation range of the cutout portion in the X-axis direction with dealing with the positional errors of the cutout portion that may be caused as described above, a formation range of the cutout portion in the Y-axis direction from the LEDs16tends to be excessively large. Accordingly, an amount of reflection light reflecting off the reflection sheet20may be decreased and use efficiency of light may be lowered. On the other hand, if the formation range of the cutout portion32in the X-axis direction is greater than the formation range of the cutout portion32in the Y-axis direction, an effect of suppressing luminance unevenness by the cutout portion32is achieved more reliably as described above while use efficiency of light is sufficiently ensured.

The liquid crystal display device10of the present embodiment has a structure as described above, and operations thereof will be described subsequently. For attachment of the liquid crystal display device10, the LED unit LU is attached by attaching the LED board17, on which the LEDs16and the board-side connector22is mounted in advance, to the heat dissipation member16. The reflection sheet20and the light guide plate19are housed in the chassis14and each LED unit LU is attached to a long-side end of the chassis14, in which the first side plate portion14bis provided. Thereafter, by attaching the second frame21to which each of the cushion materials25to27is attached to the chassis14in advance, the cushion material for the light guide plate25is disposed so as to be positioned between the second frame main body21aand the outer peripheral end of the light guide pate19and the light guide plate19is supported from the front side by the second frame21through the cushion material for the light guide plate25. Then, after the optical sheet15is placed on the third step portion21a3of the second frame main body21athrough the cushion material for the optical sheet27, the liquid crystal panel11is placed on the second step portion21a2through the cushion material for the liquid crystal panel26and the first frame13is further placed on the first step portion21a1. When the first frame13is attached to the second frame21, attachment of main components of the liquid crystal display device10is completed.

In the liquid crystal display device10to which attachment is performed as described above, work for connecting the wiring member24in order to feed power to the LED units LU of the backlight device12is carried out. An operator who carries out the work for connection, while holding the wiring-side connector23provided at an end of the wiring member24so as to sandwich with his/her finger, inserts the wiring-side connector23into the backlight device12through the chassis-side opening28and the heat dissipation member-side opening29that are respectively formed in the chassis14and the heat dissipation member18, which form the backlight device12, so as to open toward the outside of the rear side. At this time, in the chassis-side opening28and the heat dissipation member-side opening29, as illustrated inFIG. 7, the opening edges on the outside in the Y-axis direction are substantially flush with the mounting surface of the LED board17and the opening edges on the inner side are recessed so as to be farther away from the LEDs16side with respect to the light entrance surface19bof the light guide plate19, and as illustrated inFIG. 8, the opening edge on the right side in the X-axis direction has an interval to an extent that the wiring-side connector23is allowed to be arranged between the protrusion for power feeding17band the board-side connector22, so that work for fitting the wiring-side connector23to the board-side connector22from the right side to the left side inFIG. 8is able to be carried out while inserting the finger of the operator gripping the wiring-side connector23into the chassis-side opening28and the heat dissipation member-side opening29, thus workability becomes excellent.

When power of the liquid crystal display device10which is manufactured as described above is turned on, a signal associated with an image is supplied from a panel driving circuit board for driving the liquid crystal panel11to the liquid crystal panel11, and power is supplied from the LED driving circuit board to each of the LEDs16on the LED board17through the wiring member24, the wiring-side connector23and the board-side connector22, so that each of the LEDs16is turned on. As illustrated inFIG. 3, light emitted from each of the LEDs16is guided by the light guide plate19and transmitted through the optical sheet15, and thereby irradiated to the liquid crystal panel11after being converted into flat planar light, so that a predetermined image is displayed in a display area of the liquid crystal panel11.

To describe operations associated with the backlight device12in detail, when each of the LEDs16is turned on, as illustrated inFIG. 3, light emitted from each of the LEDs16enters the light guide plate19through the light entrance surface19b, and then, in a process of totally reflecting off an interface between the light guide plate19and an outside air layer or propagating in the light guide plate19with reflecting off the reflection sheet20, the light exit performance through the light exit surface19ais improved by a light reflection pattern. In this embodiment, the reflection sheet20has the extended reflection portion20awhich extends so as to be closer to the LEDs16side than the light entrance surface19band light that exists in a space between the LEDs16and the light entrance surface19breflects off the extended reflection portion20a. Therefore, the reflected light is able to enter through the light entrance surface19befficiently, thus making it possible to achieve high light entering efficiency for the light entrance surface19b. Thus, improvement in luminance and reduction in power consumption are accomplished.

On the other hand, as illustrated inFIG. 7, the chassis-side opening28is formed in the bottom plate portion14aof the chassis14in order to feed power to the LED board17and the formation part is the light guide plate non-support portion30which does not support the light guide plate19. Thus, a portion of the reflection sheet20overlapping with the chassis-side opening28, which is the light guide plate non-support portion30, is not supported from the rear side and is therefore easily deformed so as to be separated from the opposite plate surface19cof the light guide plate19. In particular, if the extended reflection portion20ais included in the overlapping portion of the reflection sheet20overlapping with the chassis-side opening28, the light reflected by the extended reflection portion20athat has been deformed so as to be separated from the opposite plate surface19cis directed to the rear side of the light guide plate19(a gap between the light guide plate19and the separated portion of the reflection sheet20) and directly enters through the opposite plate surface19cand then directly exits through the light exit surface19a, so that local bright region, that is, luminance unevenness may be caused (refer toFIG. 9). In the present embodiment, since the cutout portion32is formed in the reflection sheet20by cutting out at least a part of a portion of the extended reflection portion20aoverlapping with the chassis-side opening28, which is the light guide plate non-support portion30, a portion of the extended reflection portion20ais less likely to be separated from the opposite plate surface19cof the light guide plate19due to the chassis-side opening28, and light from the LEDs16is less likely to reflect off the extended reflection portion20aand less likely to directly enter through the opposite plate surface19c. Thereby, a bright region is hard to be locally generated on the light exit surface19a, so that luminance unevenness is less likely to be visually recognized by a user (observer) of the liquid crystal display device10. Note that, as illustrated with a long dashed double-short dashed line ofFIG. 7, even if the portion of the reflection sheet20overlapping with the chassis-side opening28, which is the light guide plate non-support portion30, is deformed so as to be separated from the opposite plate surface19cof the light guide plate19, the deformed portion does not include the extended reflection portion20a, so that the light from the LEDs16is hardly irradiated directly to the deformed portion without passing through the light guide plate19. Accordingly, the light from the LEDs16is less likely to reflect off the deformed portion and less likely to directly enter through the opposite plate surface19cof the light guide plate19, and even if the light enters, an amount thereof is quite small, so that a local bright region is hardly caused.

Furthermore, since the cutout edge of the cutout portion32is disposed so as to be recessed to be farther away from the LEDs16with respect to the light entrance surface19bof the light guide plate19as illustrated inFIG. 7, a portion of the extended reflection portion20ais further less likely to be separated from the opposite plate surface19cof the light guide plate19due to the chassis-side opening28, which is more suitable for suppression of luminance unevenness, and in addition thereto, the cutout edge of the cutout portion32is less likely to be disposed closer to the LEDs16than the light entrance surface19bbecause of an influence of tolerance of a dimension of the reflection sheet20, tolerance of attachment of the reflection sheet20to the chassis14, or the like, which is further suitable for suppression of luminance unevenness. Further, since a dimension (an opening size) of the cutout portion32in the X-axis direction continuously decreases as being farther away from the LEDs16as illustrated inFIG. 6, a dark region which may be caused in the light exit surface19adue to formation of the cutout portion32is less likely to be visually recognized by the user of the liquid crystal display device10, thus making it possible to further suitably suppress luminance unevenness. Then, since the formation range of the cutout portion32in the X-axis direction is greater than the formation range of the chassis-side opening28, which is the light guide plate non-support portion30, an amount of reflection light changes continuously between the portion of the extended reflection portion20aoverlapping with the chassis-side opening28and the portion of the extended reflection portion20aoverlapping with the light guide plate support portion31, thus a dark region that may be caused in the light exit surface19adue to formation of the cutout portion32is less likely to be visually recognized by the user of the liquid crystal display device10, thus making it possible to suppress luminance unevenness much further suitably. Moreover, since the formation range of the cutout portion32in the X-axis direction is greater than the formation range of the cutout portion32in the Y-axis direction, even if positional errors of the cutout portion32in the X-axis direction may be caused because of an influence of tolerance of a dimension of the reflection sheet20, tolerance of attachment of the reflection sheet20to the chassis14, or the like, the cutout portion32is likely to overlap with the chassis-side opening28, which is the light guide plate non-support portion30, in the X-axis direction, thus an effect of suppressing luminance unevenness by the cutout portion32is achieved more reliably.

As described above, the backlight device (lighting device)12of the present embodiment includes: the LED (light source)16; the light guide plate19having a plate shape and having at least one edge surface as the light entrance surface19bthrough which light from the LED16enters, one plate surface as the light exit surface19athrough which light exits the light guide plate, and another plate surface as the opposite plate surface19cbeing opposite to the light exit surface19a; the chassis14having the bottom plate portion14athat includes the light guide plate support portion31for supporting the light guide plate19from a side of the opposite plate surface19cand the light guide plate non-support portion30for not supporting the light guide plate19from the side of the opposite plate surface19c; and the reflection sheet (reflection member)20that is disposed between the opposite plate surface19cof the light guide plate19and the bottom plate portion14aof the chassis14and reflects light travelling through the light guide plate19toward the light exit surface19a, the reflection sheet20having the extended reflection portion20awhich extends closer to the LED16than the light entrance surface19bof the light guide plate19and having the cutout portion32that is formed by cutting out at least a part of a portion of the extended reflection portion20aoverlapping with the light guide plate non-support portion30.

Thereby, light emitted from the LEDs16enters the light guide plate19through the light entrance surface19b, and is then, for example, reflected toward the light exit surface19aby the reflection sheet20that is disposed between the opposite plate surface19copposite to the light exit surface19aand the bottom plate portion14aof the chassis14, and thereby propagating in the light guide plate19and then exits through the light exit surface19a. Since the reflection sheet20has the extended reflection portion20athat extends so as to be closer to the LEDs16than the light entrance surface19bof the light guide plate19, by reflecting the light from the LEDs16by the extended reflection portion20a, light entering efficiency for the light entrance surface19bis enhanced. On the other hand, since the bottom plate portion14aof the chassis14has the light guide plate support portion31that supports the light guide plate19from the side of the opposite plate surface19cand the light guide plate non-support portion30that does not support the light guide plate19from the side of the opposite plate surface19c, if the portion overlapping with the light guide plate non-support portion30is included in the extended reflection portion20a, the overlapping portion may be separated from the opposite plate surface19cand the separated portion reflects the light from the LEDs16to cause the light to enter the opposite plate surface19cdirectly, so that the entering light is likely to directly exit from the light exit surface19ato cause a locally bight region, that is, luminance unevenness.

In this embodiment, since the cutout portion32is formed in the reflection sheet20by cutting out at least a part of the portion of the extended reflection portion20aoverlapping with the light guide plate non-support portion30, so that a portion of the extended reflection portion20ais less likely to be separated from the opposite plate surface19cof the light guide plate19due to the light guide plate non-support portion30, and light from the LEDs16is less likely to reflect off the extended reflection portion20aand less likely to directly enter through the opposite plate surface19c. Thereby, the light which has entered through the opposite plate surface19cis less likely to directly exit through the light exit surface19a, so that luminance unevenness is hard to be caused in the light output through the light exit surface19a.

The reflection sheet20is formed so that the cutout edge of the cutout portion32is disposed so as to be opposite to the LEDs16with respect to the light entrance surface19b. According to such a configuration, compared to a configuration that the cutout edge of the cutout portion is closer to the LEDs16than the light entrance surface19b, a portion of the extended reflection portion20ais less likely to be separated from the opposite plate surface19cof the light guide plate19due to the light guide plate non-support portion30, and light from the LEDs16is less likely to reflect off the extended reflection portion20aand less likely to directly enter through the opposite plate surface19c, thus making it possible to suppress luminance unevenness more suitably. Further, compared to a configuration that the cutout edge of the cutout portion is flush with the light entrance surface19b, the cutout edge is less likely to be closer to the LEDs16than the light entrance surface19beven if positional errors may be caused in arrangement of the cutout edge of the cutout portion32because of tolerance of a dimension, tolerance of attachment or the like, thus making it possible to suppress occurrence of luminance unevenness more suitably.

The light guide plate non-support portion30is formed so that an edge thereof is disposed on an opposite side to the LEDs16with respect to the light entrance surface19b, and the reflection sheet20is formed so that the cutout edge of the cutout portion32is disposed so as to be closer to the light entrance surface19athan the edge of the light guide plate non-support portion30. Thereby, the reflection light reflecting off the reflection sheet20is sufficiently secured and use efficiency of light is less likely to be lowered, compared to a configuration that the cutout edge of the cutout portion is flush with the edge of the light guide plate non-support portion30and an amount of reflection light reflecting off the reflection sheet20decreases so that use efficiency of light is lowered. Note that, when the cutout edge of the cutout portion32is disposed so as to be closer to the light entrance surface19bthan the edge of the light guide plate non-support portion30, the portion of the extended reflection portion20amay be separated from the opposite plate surface19cof the light guide plate19due to the light guide plate non-support portion30. However, the cutout edge of the cutout portion32is flush with the light entrance surface19bor opposite to the LEDs16with respect to the light entrance surface19band therefore, the reflection light reflecting off the extended reflection portion20aextending closer to the LEDs16than the light entrance surface19bis less likely to directly enter the light guide plate19through the opposite plate surface19c, so that luminance unevenness becomes sufficiently hard to be caused.

The reflection sheet20is formed so that a dimension (an opening size) of the cutout portion32in the direction along the light entrance surface19bcontinuously decreases as being farther away from the LEDs16. Thereby, an area of the reflection sheet20, that is, an amount of reflection light reflecting off the reflection sheet20in the direction along the light entrance surface19bcontinuously changes, so that compared to a configuration that a dimension of the cutout portion in the direction along the light entrance surface19bis constant or a configuration that the dimension decreases in a stepwise manner as being farther away from the LEDs16, a dark region that may be caused in the light exit surface19adue to the cutout portion32is less likely to be visually recognized, which is more suitable for suppressing occurrence of luminance unevenness.

The reflection sheet20is formed so that a formation range of the cutout portion32in the direction along the light entrance surface19bbecomes greater than the formation range of the light guide plate non-support portion30in the direction. Thereby, since the cutout portion32extends to have a formation range overlapping with the light guide plate support portion31in the direction along the light entrance surface19b, an amount of reflection light changes continuously between the portion of the extended reflection portion20aoverlapping with the light guide plate non-support portion30and the portion of the extended reflection portion20aoverlapping with the light guide plate support portion31. Thereby, a dark region that may be caused in the light exit surface19adue to the cutout portion32is less likely to be visually recognized, which is further suitable for suppressing occurrence of luminance unevenness. Even if positional errors may be caused in arrangement of the cutout portion32because of tolerance of a dimension, tolerance of attachment, or the like, the cutout portion32is likely to be disposed so as to appropriately overlap with the light guide plate non-support portion30in the direction along the light entrance surface19b, so that an effect of suppressing luminance unevenness by the cutout portion32is achieved more reliably.

Moreover, the reflection sheet20is formed so as to have a formation range of the cutout portion32in the direction along the light entrance surface19bgreater than a formation range of the cutout portion32in the direction from the LEDs16to the light entrance surface19b. Thereby, even if positional errors may be caused in arrangement of the cutout portion32in the direction along the light entrance surface19bbecause of tolerance of a dimension, tolerance of attachment, or the like, the cutout portion32is likely to be disposed so as to appropriately overlap with the light guide plate non-support portion30in the direction along the light entrance surface19b, so that an effect of suppressing luminance unevenness by the cutout portion32is achieved more reliably. In this case, if the formation range of the cutout portion in the direction from the LEDs16to the light entrance surface19bis greater than or same as the formation range of the cutout portion in the direction along the light entrance surface19bwith dealing with the positional errors that may be caused as described above in the arrangement of the cutout portion, the formation range of the cutout portion in the direction from the LEDs16to the light entrance surface19btends to be excessively large and an amount of reflection light reflecting off the reflection sheet20decreases, so that use efficiency of light is likely to be lowered. Compared to this, if the formation range of the cutout portion32in the direction along the light entrance surface19bis greater than the formation range of the cutout portion32in the direction from the LEDs16to the light entrance surface19b, an effect of suppressing luminance unevenness by the cutout portion32as described above is achieved more reliably while sufficiently ensuring use efficiency of light.

The light guide plate non-support portion30includes the chassis-side opening (opening)28which opens toward the bottom plate portion14a. Thereby, compared to a configuration that the light guide plate non-support portion has a concave portion that is formed by recessing the bottom plate portion14a, a portion of the extended reflection portion20amay be likely to be separated from the opposite plate surface19cof the light guide plate19due to the chassis-side opening28, which is the light guide plate non-support portion30, and a distance of the separation tends to be greater. However, the reflection sheet20including the cutout portion32is less likely to have such a problem, thus making it possible to effectively suppress luminance unevenness.

The LED board (light source board)17on which the LED16is mounted, and the board-side connector22and the wiring-side connector23(power feed portion) for feeding power to the LED16on the LED board17are included, in which the bottom plate portion14ais formed so that the chassis-side opening28causes the board-side connector22and the wiring-side connector23to be exposed to outside. Thereby, when the chassis-side opening28is formed so as to cause the board-side connector22and the wiring-side connector23to be exposed to outside in the bottom plate portion14a, it is possible to pass the wiring-side connector23through the chassis-side opening28easily. In this manner, the chassis-side opening28which allows passing the wiring-side connector23therethrough is disposed near the LED board17and the light entrance surface19bof the light guide plate19in the bottom plate portion14a, and thus is easy to be disposed necessarily so as to overlap also with the extended reflection portion20aof the reflection sheet20. However, in the reflection sheet20having the cutout portion32, a portion of the extended reflection portion20ais less likely to be separated from the opposite plate surface19cof the light guide plate19due to the chassis-side opening28, which is the light guide plate non-support portion30, and light from the LEDs16is less likely to reflect off the extended reflection portion20aand is less likely to directly enter through the opposite plate surface19c, thus making it possible to effectively suppress luminance unevenness.

The LED board17has the LED mounting portion (light source mounting portion)17aon which the LEDs16are mounted, and the protrusion for power feeding17bwhich protrudes from the LED mounting portion17aalong a direction from a side of the light exit surface19ato a side of the opposite plate surface19cand in which the board-side connector22and the wiring-side connector23are disposed, in which the bottom plate portion14ais formed so that the board-side connector22, the wiring-side connector23, and the protrusion for power feeding17bare exposed to outside through the chassis-side opening28. Thereby, compared to a configuration that the board-side connector and the wiring-side connector are arranged in a part of the LED mounting portion17aand the LED mounting portion17aincludes a portion having no LED16, with a configuration including the protrusion for power feeding17bwhere the board-side connector22and the wiring-side connector23are disposed so as to be projected from the LED mounting portion17aalong the direction from the side of the light exit surface19ato the side of the opposite plate surface19c, the LED mounting portion17amay not include the portion having no LED16thereon, so that a portion in which an amount of irradiated light from the LEDs16decreases locally is less likely to be generated in the light entrance surface19bof the light guide plate19. Thereby, even if a frame of the backlight device12is increasingly narrowed and the LEDs16and the light entrance surface19bhave a closer positional relation, a dark region is less likely to be generated in light output from the light exit surface19a, thus making it possible to suppress generation of luminance unevenness associated with narrowing of the frame. In addition, since the protrusion for power feeding17bprotruding from the LED mounting portion17aalong the direction from the side of the light exit surface19ato the side of the opposite plate surface19c, and the board-side connector22and the wiring-side connector23disposed thereon are exposed to outside through the chassis-side opening28that is formed in the bottom plate portion14a, so that sufficiently enhanced workability when the wiring-side connector23is passed through the chassis-side opening28is also achieved.

The bottom plate portion14ais formed so that an opening edge of the chassis-side opening28is disposed so as to be opposite to the LEDs16with respect to the light entrance surface19b. Thereby, even if a protrusion dimension by which the protrusion for power feeding17bprotrudes from the LED mounting portion17ais small, a sufficiently large formation range of the chassis-side opening28is ensured so that the opening edge is disposed so as to be opposite to the LEDs16with respect to the light entrance surface19b, so that excellent workability is achieved for working of passing the wiring-side connector23through the chassis-side opening28. When the protrusion dimension by which the protrusion for power feeding17bprotrudes from the LED mounting portion17ais reduced, reduction in thickness of the backlight device12is accomplished.

The liquid crystal display device (display device)10according to the present embodiment includes the backlight device12, and the liquid crystal panel (display panel)11which displays an image by using light from the backlight device12. With such a liquid crystal display device10, luminance unevenness of the backlight device12is suppressed. Thus, the display device of the invention has excellent display quality associated with the image displayed on the liquid crystal panel11and is suitable for an increase in screen size.

A television device TV according to the present embodiment includes the liquid crystal display device10described above. With such a television device TV, luminance unevenness of the backlight device12included in the liquid crystal display device10is suppressed. Thus, the display device of the invention has excellent display quality associated with a television image displayed on the liquid crystal panel11and is suitable for an increase in screen size.

Embodiment 2 of the invention will be described withFIG. 10orFIG. 11. Embodiment 2 indicates a cutout portion132whose formation range in the Y-axis direction is changed. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 1 described above will be omitted.

As illustrated inFIG. 10andFIG. 11, a reflection sheet120according to the present embodiment is formed so that the cutout portion132has a center portion in the X-axis direction having a cutout edge with a greatest distance from the LEDs116and the cutout edge of the center portion is flush with a light entrance surface119bof a light guide plate119in the Y-axis direction. That is, the cutout portion132is selectively disposed only in an extended reflection portion120ain the Y-axis direction and is not formed in a main body portion (portion excluding the extended reflection portion120a) of the reflection sheet120. Even with such a configuration, compared to a configuration that the cutout edge of the cutout portion is formed so as to protrude to be closer to the LEDs116than the light entrance surface119b, a portion of the extended reflection portion120ais less likely to be separated from an opposite plate surface119cof the light guide plate119due to a chassis-side opening128, which is a light guide plate non-support portion130, and light from the LEDs116is less likely to reflect off the extended reflection portion120aand less likely to directly enter through the opposite plate surface119c, thus making it possible to suppress luminance unevenness more suitably.

According to the present embodiment described above, the reflection sheet120is formed so that the cutout edge of the cutout portion132is disposed so as to be flush with the light entrance surface119b. Thereby, compared to a configuration that the cutout edge of the cutout portion is formed so as to protrude to be closer to the LEDs116than the light entrance surface119b, a portion of the extended reflection portion120ais less likely to be separated from the opposite plate surface119cof the light guide plate119due to the light guide plate non-support portion130, and light from the LEDs116is less likely to reflect off the extended reflection portion120aand less likely to directly enter through the opposite plate surface119cr, thus making it possible to suppress luminance unevenness more suitably.

Embodiment 3 of the invention will be described withFIG. 12. Embodiment 3 indicates a cutout portion232whose plan shape is changed from that of Embodiment 1 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 1 described above will be omitted.

As illustrated inFIG. 12, a reflection sheet220according to the present embodiment is formed so that a plan shape of the cutout portion232is substantially trapezoid shape (specifically, even-leg trapezoid). Accordingly, a cutout edge of the cutout portion232includes a pair of inclined portions233, and a straight portion34that connects center-side ends of the pair of inclined portions233of the cutout portion232and is almost straight along the X-axis direction. The cutout portion232is formed so that a distance from the cutout edge to LEDs216in the Y-axis direction continuously increases as being closer to the straight portion34in the X-axis direction and, to the contrary, continuously decreases as being farther away from the straight portion34in the X-axis direction in a formation rage of each of the inclined portion233. On the other hand, the cutout portion232has a formation range of the straight portion34in which a distance from the cutout edge to the LEDs216in the Y-axis direction is constant over an entire area. The distance is longer than a distance from a light entrance surface219bto the LEDs216in the Y-axis direction. With such a configuration, since an area of the cutout portion232formed in an extended reflection portion220ais relatively larger than what is described in Embodiment 1 above, a portion of the extended reflection portion220ais further less likely to be separated from an opposite plate surface of a light guide plate219due to a chassis-side opening228, which is a light guide plate non-support portion230, thus making it possible to suppress luminance unevenness more suitably.

Embodiment 4 of the invention will be described withFIG. 13. Embodiment 4 indicates a cutout portion332whose plan shape is changed from that of Embodiment 1 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 1 described above will be omitted.

As, illustrated inFIG. 13, a reflection sheet320according to the present embodiment is formed so that a plan shape of the cutout portion332is a substantially bow shape and a cutout edge thereof is a circular arc portion35. The cutout portion332is formed so that the circular arc portion35, which is the cutout edge, is recessed so as to be farther away from LEDs316and any tangent lines thereof have an inclined shape to the X-axis direction and the Y-axis direction (in which, a contact line to a center portion of the circular arc portion35in the X-axis direction is excluded). That is, the cutout portion332is formed so that a center of a circle including the circular arc portion35which forms the cutout edge is positioned so as to be closer to the LEDs316with respect to the cutout edge in the Y-axis direction. In such a configuration as well, similarly to Embodiment 1 described above, the cutout portion332is formed so that a dimension in the X-axis direction continuously decreases as being farther away from the LEDs316, thus making it possible to achieve effect of suppressing luminance unevenness similar to Embodiment 1.

Embodiment 5 of the invention will be described withFIG. 14. Embodiment 5 indicates a cutout portion432whose plan shape is further changed from that of Embodiment 4 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 4 described above will be omitted.

As illustrated inFIG. 14, a reflection sheet420according to the present embodiment is formed so that a plan shape in the cutout portion432is a substantially V-shape and a cutout edge thereof includes a pair of circular arc portions435. The cutout edge432is formed so that the pair of circular arc portions435, which is the cutout edge, each projects to LEDs416side, and any tangent lines thereof have an inclined shape to the X-axis direction and the Y-axis direction. That is, the cutout portion432is formed so that a center of a circle including each circular arc portion435which forms the cutout edge is positioned so as to be opposite to the LEDs416with respect to the cutout edge in the Y-axis direction.

Embodiment 6 of the invention will be described withFIG. 15. Embodiment 6 indicates a cutout portion532whose plan shape is changed from that of Embodiment 1 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 1 described above will be omitted.

As illustrated inFIG. 15, a reflection sheet520according to the present embodiment is formed so as to have a configuration in which inclined portions533that form a cutout edge of the cutout portion532are bent in the middle so that inclination angles to the X-axis direction and the Y-axis direction change in the middle. Each of the inclined portions533includes a first inclined portion36that is disposed in the center side of the cutout portion532in the X-axis direction and a second inclined portion37that is disposed in the end side of the cutout portion532in the X-axis direction, and is configured so that the inclination angles to the X-axis direction and the Y-axis direction change in two steps. The first inclined portion36is formed so that an inclination angle formed with respect to the Y-axis direction is smaller than an inclination angle formed with respect to the Y-axis direction of the second inclined portion37and an inclination angle formed with respect to the X-axis direction is larger than an inclination angle formed with respect to the X-axis direction of the second inclined portion37. In such a configuration as well, similarly to Embodiment 1 described above, the cutout portion532is formed so that a dimension in the X-axis direction continuously decreases as being farther away from LEDs516, thus making it possible to achieve effect of suppressing luminance unevenness similar to Embodiment 1.

Embodiment 7 of the invention will be described withFIG. 16orFIG. 17. Embodiment 7 indicates a cutout portion632whose formation range in the Y-axis direction is further changed from that of Embodiment 2 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 2 described above will be omitted.

As illustrated inFIG. 16andFIG. 17, a reflection sheet620according to the present embodiment is formed so that a cutout edge of a center portion of the cutout portion632in the X-axis direction has a longest distance from LEDs616and the cutout edge is arranged closer to the LEDs616than a light entrance surface619bof a light guide plate619in the Y-axis direction. Even with such a configuration, since a portion of an extended reflection portion620a, which is the closest to the LEDs616, is cut out by forming the cutout portion632, compared to a configuration without having a cutout portion, a portion of the extended reflection portion620ais less likely to be separated from an opposite plate surface619cof the light guide plate619due to a chassis-side opening628, which is a light guide plate non-support portion630, and light from the LEDs616is less likely to reflect off the extended reflection portion620aand less likely to directly enter through the opposite plate surface619c, thus making it possible to suppress luminance unevenness more suitably.

Embodiment 8 of the invention will be described withFIG. 18orFIG. 19. Embodiment 8 indicates a bottom plate portion714aof a chassis714in which a reinforcement rib38is formed compared to Embodiment 1 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 1 described above will be omitted.

As illustrated inFIG. 18andFIG. 19, the bottom plate portion714aforming the chassis714according to the present embodiment is provided with the reinforcement rib (recessed portion)38that is partially recessed to the rear side. The reinforcement rib38is formed integrally with the bottom plate portion714aby performing drawing, and has a cross-sectional shape in a substantially trapezoid shape in which a bottom portion is disposed behind the bottom plate portion714a. The reinforcement rib38is formed so as to be disposed in the bottom plate portion714aat a position of being adjacent to a chassis-side opening728and so that a formation range in the X-axis direction is larger than a formation range in the X-axis direction of the chassis-side opening728. Specifically, the reinforcement rib38includes a first reinforcement portion38a, a pair of second reinforcement portions38b, and a pair of third reinforcement portions38c. The first reinforcement portion38ais formed so as to surround the chassis-side opening728in a plan view and extends along the X-axis direction and has a length dimension greater than a dimension of the chassis-side opening728in the X-axis direction. The pair of second reinforcement portions38bextends toward LEDs716from respective ends of the first reinforcement portion38ain a length direction. The pair of third reinforcement portions38cextends so as to be mutually away from an extended end of each of the second reinforcement portions38balong the X-axis direction. Among them, the first reinforcement portion38ais arranged to overlap with an entire area of the chassis-side opening728in the X-axis direction, while the second reinforcement portions38band the third reinforcement portions38care arranged to partially overlap with the chassis-side opening728in the Y-axis direction. When such a reinforcement rib38is formed in the bottom plate portion714a, reduction in strength, which is caused in the bottom plate portion714aas the chassis-side opening728is formed, is able to be compensated for.

However, if the reinforcement rib38as described above is formed in the bottom plate portion714a, according to processing thereof, a deformation portion39caused by warpage or bending may be formed in a portion of the bottom plate portion714aadjacent to the reinforcement rib38, and the deformation portion39may be likely to be formed particularly at a position closer to an outer edge of the bottom plate portion714awith respect to the reinforcement rib38. If the deformation portion39is formed at the position closer to the outer edge of the bottom plate portion714awith respect to the reinforcement rib38, the deformation portion39is likely to be arranged so as to overlap with an extended reflection portion720aof the reflection sheet720in a plan view. The deformation portion39has a distance from an opposite plate surface719cof a light guide plate719relatively greater than a distance between the opposite plate surface719cof the light guide plate719and a light guide plate support portion731, so that the reinforcement rib38and the deformation portion39constitute a second light guide plate non-support portion40that does not support the light guide plate719. On the other hand, in the present embodiment, a cutout portion732of the reflection sheet720is formed in a range of the extended reflection portion720aoverlapping not only with the chassis-side opening728, which is a light guide plate non-support portion730, but also with the deformation portion39included in the second light guide plate non-support portion40in a plan view. Thereby, a portion of the extended reflection portion720ais less likely to be separated from the opposite plate surface719cof the light guide plate719due to the deformation portion39, which forms the second light guide plate non-support portion40, and light from the LEDs716is less likely to reflect off the extended reflection portion720aand less likely to directly enter through the opposite plate surface719c. Thereby, a bright region becomes hard to be locally generated in the light exit surface719a, thus luminance unevenness is hard to be caused.

According to the present embodiment, as described above, the light guide plate non-support portion730includes the reinforcement rib (recessed portion)38that is formed by recessing the bottom plate portion714aso as to be farther away from the light guide plate719, and the deformation portion39adjacent to the reinforcement rib38in the bottom plate portion714aand having a distance from the opposite plate surface719cof the light guide plate719relatively greater than a distance between the opposite plate surface719cof the light guide plate719and the light guide plate support portion731. If the reinforcement rib38that is recessed so as to be farther away from the light guide plate719is formed in the bottom plate portion714a, the deformation portion39may be generated by warpage or bending in the bottom plate portion714aand such a deformation portion39is in a portion of the bottom plate portion714aadjacent to the reinforcement rib38. Thus, for example, even if the reinforcement rib38is formed not overlapping with the extended reflection portion720aof the reflection sheet720, the deformation portion39may be formed in a portion of the bottom plate portion714aoverlapping with the extended reflection portion720aof the reflection sheet720. The deformation portion39is away from the opposite plate surface719cof the light guide plate719with a distance relatively greater than a distance between the opposite plate surface719cof the light guide plate719and the light guide plate support portion731. In the reflection sheet720having the cutout portion732, a portion of the extended reflection portion720ais less likely to be separated from the opposite plate surface719cof the light guide plate719due to the deformation portion39, which is the light guide plate non-support portion730, and light from the LEDs716is less likely to reflect off the extended reflection portion720aand is less likely to directly enter through the opposite plate surface719c, thus making it possible to effectively suppress luminance unevenness.

Embodiment 9 of the invention will be described withFIG. 20orFIG. 21. Embodiment 9 indicates a bottom plate portion814aof a chassis814in which a board attachment portion41is provided compared to Embodiment 1 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 1 described above will be omitted.

As illustrated inFIG. 20andFIG. 21, the bottom plate portion814aforming the chassis814according to the present embodiment is provided with the board attachment portion (recessed portion)41so as to be partially recessed to the rear side. The board attachment portion41is formed integrally with the bottom plate portion814aby performing drawing, and has a cross-sectional shape such that the bottom portion is disposed behind the bottom plate portion814aand the bottom portion has a substantially trapezoid shape larger than that of the reinforcement rib38described in Embodiment 8 described above. A board42disposed behind the bottom plate portion814ais attached to the board attachment portion41by a screw member SM. The board42includes a panel driving circuit board for driving a liquid crystal panel811, an LED driving circuit board for supplying power to LEDs816, and the like. Note that, in the present embodiment, provided is a configuration in which the chassis-side opening28described in Embodiment 1 above is not formed in the chassis814.

When the board attachment portion41as described above is formed in the bottom plate portion814a, according to processing thereof, a deformation portion839may be formed in a portion of the bottom plate portion814aadjacent to the board attachment portion41by warpage or bending, and the deformation portion839is likely to be formed particularly at a position closer to an outer edge of the bottom plate portion814awith respect to the board attachment portion41. If the deformation portion839is formed at the position closer to the outer end of the bottom plate portion814awith respect to the board attachment portion41, the deformation portion839is likely to be arranged so as to overlap with an extended reflection portion820aof the reflection sheet820in a plan view. The deformation portion839has a distance from an opposite plate surface819cof a light guide plate819relatively longer than a distance between the opposite plate surface819cof the light guide plate819and a light guide plate support portion831, and thus the deformation portion839and the board attachment portion41constitute a light guide plate non-support portion830which does not support the light guide plate819. On the other hand, in the present embodiment, a cutout portion832of the reflection sheet820is formed in a range of the extended reflection portion820aoverlapping with the deformation portion839included in the light guide plate non-support portion830in a plan view. Thereby, a portion of the extended reflection portion820ais less likely to be separated from the opposite plate surface819cof the light guide plate819due to the deformation portion839included in the light guide plate non-support portion830, and light from the LEDs816is less likely to reflect off the extended reflection portion820aand less likely to directly enter through the opposite plate surface819c. Thereby, a bright region is hard to be locally generated in the light exit surface819a, thus luminance unevenness is hard to be caused.

As described above, according to the present embodiment, the board42which is provided so as to be opposite to the light guide plate819with respect to the bottom plate portion814aand is attached to the board attachment portion (recessed portion)41. This makes it possible to attach the board42, which is provided so as to be opposite to the light guide plate819with respect to the bottom plate portion814a, by using the board attachment portion41. In other words, even if the deformation portion839may be formed in the bottom plate portion814aaccording to the formation of the board attachment portion41in the bottom plate portion814ain order to attach the board42, the reflection sheet820including the cutout portion832effectively suppresses luminance unevenness resulting from the deformation portion839.

Embodiment 10 of the invention will be described withFIG. 22. Embodiment 10 indicates a double edge type backlight device912which is changed from one in Embodiment 1 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 1 described above will be omitted.

In the backlight device912according to the present embodiment, as illustrated inFIG. 22, two sets of LED units LU are arranged so as to hold a light guide plate919from both sides in a short-side direction (Y-axis direction), so that both long-side end surfaces of the light guide plate919are light entrance surfaces919b. Accordingly, only both short-side end surfaces of the light guide plate919form end surfaces not facing LEDs which do not face LEDs916. Each of the LED units LU is attached to each of the both long-side ends of a chassis914, and accordingly, chassis-side openings928are formed so that one of them is disposed so as to cross a first side plate portion914bfrom one long-side end of the bottom plate portion914a, and the other of them is disposed so as to cross a second side plate portion914cfrom the other long-side end of the bottom plate portion914a. The second side plate portion914cis formed so as to protrude toward a rear side from the bottom plate portion914asimilarly to the first side plate portion914b. In a reflection sheet920, each of both long-side ends thereof serves as an extended reflection portion920a, and each cutout portion932is formed at a portion overlapping with the chassis-side opening928in a plan view (including the extended reflection portion920a).

Embodiment 11 of the invention will be described withFIG. 23orFIG. 24. Embodiment 11 indicates one in which the heat dissipation member18is omitted and a chassis1014has a different structure, compared to Embodiment 1 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 1 described above will be omitted.

As illustrated inFIG. 23, in the chassis1014according to the present embodiment, an LED board housing portion43in which an LED board1017is housed is provided at one long-side end of a bottom plate portion1014a. The LED board housing portion43includes a first side portion43athat protrudes toward a rear side from the long-side end of the bottom plate portion1014a, a bottom portion43bthat extends so as to be farther away from the bottom plate portion1014awith respect to an protruding end of the first side portion43aalong the Y-axis direction, and a second side portion43cthat upstands to the front side from an extending end of the bottom portion43b. The LED board1017on which LEDs1016are mounted is housed in an inner space of the LED board housing portion43. The LED board1017is attached so as to be in contact with the second side portion43cwhich forms the LED board housing portion43.

As illustrated inFIG. 24, the bottom plate portion1014aand the LED board housing portion43include a chassis-side opening1028through which a board-side connector1022and a wiring-side connector1023are exposed to outside on a rear side thereof. The chassis-side opening1028is formed in a range over entire areas of the first side portion43aand the bottom portion43bof the LED board housing portion43in the Y-axis direction and a long-side end of the bottom plate portion1014a, which is adjacent to the LED board housing portion43. In such a configuration, the chassis-side opening1028, which is a light guide plate non-support portion1030, is arranged to overlap with a part of an extended reflection portion1020aof a reflection sheet1020. On the other hand, in the present embodiment, a cutout portion1032formed in the reflection sheet1020is formed in a range of the extended reflection portion1020aoverlapping with the chassis-side opening1028forming the light guide plate non-support portion1030in a plan view. Thereby, a portion of the extended reflection portion1020ais less likely to be separated from an opposite plate surface1019cof a light guide plate1019due to the chassis-side opening1028that forms the light guide plate non-support portion1030, and light from the LEDs1016is less likely to reflect off the extended reflection portion1020aand is less likely to directly enter through the opposite plate surface1019c. Thereby, a bright region is hard to be locally generated in a light exit surface1019a, thus luminance unevenness is hard to be caused.

Embodiment 12 of the invention will be described withFIG. 25. Embodiment 12 indicates one in which a reinforcement rib1138described in Embodiment 8 above is formed in a bottom plate portion1114adescribed in Embodiment 11 above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiments 8 and 11 described above will be omitted.

As illustrated inFIG. 25, the bottom plate portion1114aforming a chassis1114according to the present embodiment is provided with the reinforcement rib1138for reinforcing the bottom plate portion1114a. As the reinforcement rib1138is formed, a deformation portion1138is formed in the bottom plate portion1114a, and the deformation portion1139forms a second light guide plate non-support portion1140, which does not support a light guide plate1119, with the reinforcement rib1138. On the other hand, in the present embodiment, a cutout portion1132formed in a reflection sheet1120is formed in a range of an extended reflection portion1120aoverlapping with the deformation portion1139included in the second light guide plate non-support portion1140in a plan view. Thereby, a portion of the extended reflection portion1120ais less likely to be separated from an opposite plate surface1119cof a light guide plate1119due to the deformation portion1139included in the second light guide plate non-support portion1140, and light from LEDs1116is less likely to reflect off the extended reflection portion1120aand is less likely to directly enter through the opposite plate surface1119c. Thereby, a bright region is hard to be locally generated in a light exit surface1119a, thus luminance unevenness is hard to be caused.

Embodiment 13 of the invention will be described withFIG. 26. Embodiment 13 indicates one in which a board attachment portion1241described in Embodiment 9 above is formed in a bottom plate portion1214adescribed in Embodiment 11 above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiments 9 and 11 described above will be omitted.

As illustrated inFIG. 26, the board attachment portion1241to which a board1242disposed behind the bottom plate portion1214ais attached is formed in the bottom plate portion1214aforming a chassis1214according to the present embodiment. As the board attachment portion1241is formed, a deformation portion1239is formed in the bottom plate portion1214a, and the deformation portion1239and the board attachment portion1241constitute a light guide plate non-support portion1230that does not support a light guide plate1219. On the other hand, in the present embodiment, a cutout portion1232formed in a reflection sheet1220is formed in a range of an extended reflection portion1120a, which overlaps with the deformation portion1239forming the light guide plate non-support portion1230in a plan view. Thereby, a portion of an extended reflection portion1220ais less likely to be separated from an opposite plate surface1219cof the light guide plate1219due to the deformation portion1239included in the light guide plate non-support portion1230, and light from LEDs1216is less likely to reflect off the extended reflection portion1220aand is less likely to directly enter through the opposite plate surface1219c. Thereby, a bright region is hard to be locally generated in a light exit surface1219a, thus luminance unevenness is hard to be caused.

Embodiment 14 of the invention will be described withFIG. 27. Embodiment 14 indicates one in which a chassis1314has a structure which is further changed compared to one in Embodiment 11 described above. Note that, overlapping description for structures, actions, and effects similar to those of Embodiment 11 described above will be omitted.

In the chassis1314according to the present embodiment, as illustrated inFIG. 27, a first side plate portion1314bis formed so as to upstand toward a front side from an end of a bottom plate portion1314aon an LED board1317side, and the LED board1317is attached so as to be in contact with the first side plate portion1314b. A chassis-side opening1328which is formed in the bottom plate portion1314ahas an outer opening edge formed so as to be flush with a surface of the first side plate portion1314bto which the LED board1317is attached, and is thus allowed to pass a protrusion for power feeding1317bof the LED board1317and a board-side connector1322therethrough. The protrusion for power feeding1317band board-side connector1322are disposed so as to protrude to outside on a rear side of the bottom plate portion1314athrough the chassis-side opening1328, and a wiring-side connector1323is allowed to be connected to the board-side connector1322by fitting with each other.

The invention is not limited to the embodiments explained in the aforementioned description and drawings, and the following embodiments are included in a technical scope of the invention, for example.

(1) As a modified example of Embodiment 3 described above, as illustrated inFIG. 28, it may be configured so that a straight portion1434which forms a cutout edge of a cutout portion1432is flush with a light entrance surface1419aof a light guide plate1419.

(2) As a modified example of Embodiment 4 described above, as illustrated inFIG. 29, it may be configured so that a portion of a circular arc portion1535forming a cutout edge of a cutout portion1532, which has a longest distance from LEDs1516in the Y-axis direction, is flush with a light entrance surface1519bof a light guide plate1519.

(3) Configurations described in Embodiments 2 and 7 above may be, of course, combined appropriately with ones described in Embodiments 5, 6 and 8 to 14 above.

(4) A configuration described in Embodiment 7 above may be, of course, combined appropriately with ones described in Embodiments 3 and 4 above.

(5) Though Embodiment 8 above indicates a case where the deformation portion is formed in the end of the bottom plate portion as the reinforcement rib is formed, even when such a reinforcement rib is not formed, the deformation portion is formed in some cases due to generation of warpage or bending at the end of the bottom plate portion, and also when such a deformation portion is formed, by forming a cutout portion of a reflection sheet, it is possible to suppress luminance unevenness resulting from the deformation portion.

(6) In addition to each embodiment described above, plan shapes of the cutout portion and the cutout edge thereof may be changed appropriately. Specifically, the plan shape of the cutout portion may be aright angled triangle, a right angled triangle, an inequilateral triangle, an uneven-leg trapezoid, an ellipse or the like.

(7) In addition to each embodiment described above, arrangement in the X-axis direction, the installation number of cutout portions in the reflection sheet, and the like may be changed appropriately. A formation range in the X-axis direction and a formation range in the Y-axis direction in the cutout portion may be changed appropriately. Specifically, for example, it may be configured so that the cutout edge in the cutout portion, which has a longest distance from the LEDs, is flush with an end of the light guide plate non-support portion. Further, a formation range in which the cutout portion overlaps with an entire area of the light guide plate non-support portion may be provided. When it is configured so that the cutout edge of the cutout portion intersects with the light entrance surface of the light guide plate in a plan view, the intersection part may be arranged so as to be disposed in and overlap with the light guide plate non-support portion, and further, the intersection part may be arranged so as to intersect with an edge of the light guide plate non-support portion.

(8) Embodiments 8 and 12 above indicate a case where the reinforcement rib is provided in the chassis in which the chassis-side opening is formed, the invention may be applied also to a configuration in which the reinforcement rib is provided in a chassis in which a chassis-side opening is not formed as Embodiments 9 and 13 above.

(9) Though Embodiments 8, 9, 12 and 13 above indicate a case where the reinforcement rib or the board attachment portion which is a recessed portion is arranged so as not to overlap with the extended reflection portion of the reflection sheet in a plan view, arranging the reinforcement rib or the board attachment portion which is the recessed portion so as to overlap with the extended reflection portion of the reflection sheet in a plan view is also included in the invention.

(10) Though each embodiment above indicates a case where the wiring-side connector is fitted with the board-side connector along the X-axis direction, a direction in which the wiring-side connector is fitted with the board-side connector may be matched with the Z-axis direction or matched with the Y-axis direction.

(11) Though each embodiment above exemplifies a configuration in which the board-side connector is provided in the LED board, it may be configured so that when the board side connector is omitted, for example, a terminal portion for power feeding is provided in the protrusion for power feeding of the LED board and the wiring-side connector is attached to the protrusion for power feeding, the wiring-side connector is electrically connected to the terminal portion for power feeding.

(12) Though each embodiment above indicates a case where LED groups belonging to each group are connected in parallel by each wiring pattern formed in the LED board, it may be configured so that the LED groups belonging to each group are connected in series by each wiring pattern.

(13) Though each embodiment above indicates a case where two lines of wiring patterns are formed in the LED board, three or more lines of wiring patterns or only one line of wiring pattern may be formed in the LED board.

(14) Though each embodiment above indicates a configuration in which the protrusion for power feeding is connected to the center position in the length direction of the LED mounting portion, a position at which the protrusion for power feeding is connected to the LED mounting portion may be changed appropriately, so that it may be configured so that the protrusion for power feeding is connected to, for example, an end of the LED mounting portion in the length direction. In this case, as arrangement of the protrusion for power feeding is changed, arrangement of the chassis-side opening, the heat dissipation member-side opening, and the cutout portion of the reflection sheet may be changed.

(15) Though each embodiment above indicates a configuration in which only one protrusion for power feeding is connected to the LED mounting portion, it may be configured so that a plurality of protrusions for power feeding are connected to the LED mounting portion. In this case, as the installation number of protrusions for power feeding is changed, the installation number of chassis-side openings, heat dissipation member-side openings, and cutout portions of the reflection sheet may be changed.

(16) Though each embodiment above indicates a case where the chassis-side opening and the heat dissipation member-side opening are formed in a range of overlapping with entire areas of the board-side connector and the wiring-side connector in a plan view, forming the chassis-side opening and the heat dissipation member-side opening in a range of overlapping with only a part of the board-side connector and the wiring-side connector in a plan view is also included in the invention. Further, forming the chassis-side opening and the heat dissipation member-side opening in a range of not overlapping with the board-side connector or the wiring-side connector in a plan view is also included in the invention.

(17) Though each embodiment above exemplifies the liquid crystal display device including a single edge type or double edge type backlight device in which the LED board (LED, LED unit) is disposed facing a long-side end of the light guide pate, the invention may be applied also to a liquid crystal display device including a single edge type or double edge type backlight device in which the LED board is disposed facing a short-side end of the light guide plate. Additionally, the invention may be applied also to one disposing the LED board facing any three facing surfaces of the light guide plate or one disposing the LED board facing all end surfaces of the light guide plate.

(18) Though each embodiment above indicates a case where the first frame is made of metal, the first frame may be made of synthetic resin. Similarly, the second frame may be made of metal.

(19) Though each embodiment above exemplifies a case where two LED boards (LED units) are arranged so as to face one end surface of the light guide plate, one LED board or three or more LED boards may be arranged so as to face one end surface of the light guide plate.

(20) Though each embodiment above indicates a case where the LED is used as the light source, other light sources such as organic EL, a cold-cathode tube and a hot-cathode tube may be used.

(21) Though each embodiment above exemplifies a case where the liquid crystal panel has color sections of a color filter in three colors i.e., R, G and B, color sections of four or more colors may be used.

(22) Though TFT is used as a switching component of the liquid crystal display device in each embodiment above, the invention may be applied also to a liquid crystal display device using a switching component other than the TFT (for example, Thin Film Diode (TFD)), and may be applied also to a liquid crystal display device which performs monochrome display in addition to a liquid crystal display device which performs color display.

(23) Though each embodiment above exemplifies the liquid crystal display device using the liquid crystal panel as a display panel, the invention may be applied also to a display device using a display panel of other type.

(24) Though each embodiment above exemplifies the television device including a tuner, the invention may be also applied to a display device not including a tuner. Specifically, the invention may be applied also to a liquid crystal display device used as an electronic signboard (digital signage) or an electronic blackboard.

REFERENCE SIGNS LIST

14a,714a,814a,914a,1014a,1114a,1214a,1314abottom plate portion

17b,1317bprotrusion for power feeding

19,119,219,619,719,819,919,1019,1119,1219,1419,1519light guide plate

19a,719a,819a,1019a,1119a,1219alight exit surface

19b,119b,219b,619b,919b,1419b,1519blight entrance surface

19c,119c,619c,719c,819c,1019c,1119c,1219copposite plate surface

31,731,831light guide plate support portion

42,1242board TV television device