Lighting device, display device and television receiver

An object of the present invention is to reduce the tendency that local deformation occurs in an extending member in a backlight unit. A backlight unit 12 of the present invention includes LEDs 17 as light sources, a chassis 14 that stores the LEDs 17, a reflection sheet 21 and an LED substrate 18 as extending members extending along an inner surface of the chassis 14 and a holding member 20 that holds the reflection sheet 21 and the LED substrate 18 with the chassis 14 such that the reflection sheet 21 and the LED substrate 18 are sandwiched between the holding member 20 and the chassis 14. The holding member 20 is fixed to the chassis 14. The holding member 20 includes contact portions 26 that protrude toward the reflection sheet 21 and the LED substrate 18. The contact portions 26 are in contact with the reflection sheet 21 and the LED substrate 18.

TECHNICAL FIELD

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

BACKGROUND ART

For example, a liquid crystal panel used for a liquid crystal display device such as a liquid crystal television set does not emit light by itself, and therefore, requires a separate backlight unit as a lighting device. The backlight unit is installed on a back side of the liquid crystal panel (side opposite to a display surface) and includes a chassis, a surface of which is opened on the side of the liquid crystal panel, a light source stored in the chassis, a reflection sheet that is arranged along an inner surface of the chassis and reflects light on the side of the opening of the chassis, and an optical member (diffuser sheet, etc.) that is arranged on the opening side of the chassis and efficiently discharges light emitted from the light source to the liquid crystal panel. Among the above-mentioned constituents of the backlight unit, the light source adopts, for example, an LED, and in such case, an LED substrate that mounts the LED thereon is stored in the chassis.

An example of the backlight unit using the LED as the light source is described in Patent Document 1.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: Japanese Unexamined Patent Publication 2007-317423

Problem to be Solved by the Invention

In the backlight unit with the above-mentioned configuration, the LED substrate arranged in the chassis together with the reflection sheet may be fixed to the chassis by means of a screw. At this time, when the LED substrate and the reflection sheet are fixed to multiple positions with the screws, following problems can occur.

That is, when thermal environment in the backlight unit changes, the LED substrate and the reflection sheet may expand or contract due to thermal expansion or thermal contraction. Here, when the LED substrate and the reflection sheet are strongly fixed to multiple positions with the screws, since expansion and contraction are restricted at the fixed places, local deformation such as warp and flexure is easy to be generated at unfixed places. When the reflection sheet has such deformation, irregularity in reflected light easily occurs, thereby exerting a negative effect on display quality. When the LED substrate has such deformation, a contact failure occurs at a connecting portion with an external circuit or the like, thereby possibly causing a deficiency in performing lighting control of the LED.

DISCLOSURE OF THE PRESENT INVENTION

The present invention was made in view of the forgoing circumstances, and the object is to reduce the tendency to generate local deformation in an extending member.

Means for Solving the Problem

A lighting device according to the present invention includes a light source, a chassis storing the light source therein, an extending member, and a holding member. The extending member extends along an inner surface of the chassis. The holding member is fixed to the chassis and holds the extending member to the chassis such that the extending member is sandwiched between the holding member and the chassis. The holding member includes a contact portion that protrudes toward the extending member and is in contact with the extending member.

With this configuration, when the holding member is fixed to the chassis, the extending member is sandwiched between the holding member and the chassis. Since the holding member includes the contact portion that protrudes toward the extending member and is in contact with the extending member, as compared to the case where the entire surface of the holding member, which is opposite to the extending member, is in contact with the extending member, the contact area of the holding member with the extending member can be reduced. Conversely speaking, in the extending member, the area of the part that is not in contact with the holding member and thus, is not pressed by the holding member increases. When thermal expansion or thermal contraction occurs due to change in the thermal environment, the unpressed part is easier to expand or contract than the part that is in contact with the holding member and is pressed by the holding member. When the area of the unpressed part increases, the degree of flexibility in expansion or contraction of the entirety of the extending member is enhanced, thereby preventing local deformation such as flexure or warp due to expansion or contraction.

By reducing the contact area of the holding member with the extending member as described above, the thermally expanded or contracted extending member can easily slide with respect to the contact place (contact portion) of the holding member, resulting in that the degree of flexibility in expansion or contraction of the extending member can be improved.

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment

A first embodiment of the present invention will be described with reference toFIGS. 1 to 17. In this embodiment, a liquid crystal display device10is used as an example. A part of each figure shows an X-axis, a Y-axis and Z-axis, and a direction of each axis is represented in each figure. It is given that an upper side inFIGS. 4 and 5is a front side and a lower side in these figures is a back side.

A television receiver TV according to this embodiment includes, as shown inFIG. 1, the liquid crystal display device10, front and back cabinets Ca, Cb that store the liquid crystal display device10therebetween, a power source P, a tuner T and a stand S. The liquid crystal display device (display device)10is shaped like an oblong quadrangle as a whole (rectangular) and is stored in a longitudinally mounted state. The liquid crystal display device10includes, as shown inFIG. 2, a liquid crystal panel11as a display panel and a backlight unit (lighting device)12as an external light source, and these constituents are integrally held by a frame-like bezel13or the like. In this embodiment, it is assumed that a screen size is 42 inches and an aspect ratio is 16:9.

Next, the liquid crystal panel11and the backlight unit12that constitute the liquid crystal display device10will be successively described. The liquid crystal panel (display panel)11among them is rectangular in a plan view, and is formed by sticking a pair of glass substrates to each other with a predetermined gap therebetween and filling a liquid crystal between both the glass substrates. One glass substrate is provided with a switching component (for example, TFT) connected to a source wiring and a gate wiring that are orthogonal to each other, a pixel electrode connected to the switching component and an alignment film, and the other glass substrate is provided with a color filter in which color sections of R (red), G (green), B (blue) are arranged in a predetermined pattern, a counter electrode and an alignment film and the like. Polarizing plates are provided outer of both the substrates.

Subsequently, the backlight unit12will be described in detail. The backlight unit12includes, as shown inFIG. 2, a substantially box-like chassis14having openings14bon the side of a light emitting surface (the side of the liquid crystal panel11), an optical member group15(a diffuser (light diffusing member)15a, and a plurality of optical sheets15barranged between the diffuser15aand the liquid crystal panel11) arranged so as to cover the openings14bof the chassis14, and a frame16that is arranged along an outer edge of the chassis14and holds an outer edge of the optical member group15between the frame16and the chassis14. In the chassis14, as shown inFIGS. 3 to 5, LEDs17(Light Emitting Diode) as light sources, LED substrates18(extending member) that mount the LEDs17thereon and diffuser lenses19attached at positions corresponding to the LEDs17on the LED substrates18are provided. In the chassis14, holding members20capable of holding the LED substrates18between the holding members20and the chassis14, and a reflection sheet21(extending member) reflecting light in the chassis14toward the optical member15are provided. In the backlight unit12, the side of the optical member15, not the LEDs17, is set as a light emitting side. Hereinafter, each constituent of the backlight unit12will be described in detail.

The chassis14is made of metal, and as shown inFIGS. 3 to 5, is constituted of a rectangular bottom plate14alike the liquid crystal panel11, side plates14crising from outer ends of sides of the bottom plate14aand receiving plates14dextending outward from rising ends of the respective side plates14c, and is shaped like a shallow box (substantially shallow dish) opened toward the front side8as a whole. In the chassis14, its long-side direction corresponds to the X-axis direction (horizontal direction) and its short-side direction corresponds to the Y-axis direction (vertical direction). The frame16and the below-mentioned optical member15can be mounted on each of the receiving plates14dof the chassis14from the front side. The frame16is secured to each of the receiving plates14dwith a screw. Attachment holes14efor attaching the holding members20are provided in the bottom plate14aof the chassis14. The plurality of attachment holes14ecorresponding to attachment positions of the holding members20is distributed on the bottom plate14a.

As shown inFIG. 2, like the liquid crystal panel11and the chassis14, the optical member15is shaped like an oblong quadrangle (rectangular) in a plan view. As shown inFIGS. 4 and 5, the optical member15covers the openings14bof the chassis14by placing its outer edge on the receiving plates14d, and is interposed between the liquid crystal panel11and the LEDs17. The optical member15is constituted of the diffuser15aarranged on the back side (the side of the LEDs17, the side opposite to the light-emitting side) and the optical sheets15barranged on the front side (the side of the liquid crystal panel11, the light-emitting side). The diffuser15ais formed by dispersing multiple diffusing particles in a substantially transparent resin base member having a predetermined thickness and has a function of diffusing transmitted light. The optical sheet15bis shaped like a thinner sheet than the diffuser15aand two sheets are laminated (FIGS. 7 to 9). Specific examples of the optical sheets15bincludes diffuser sheets, lens sheets, reflection type polarizing sheets, and it is possible to select and use any of these sheets as appropriate.

As shown inFIG. 2, the frame16is shaped like a frame along outer circumferences of the liquid crystal panel11and the optical member15. An outer edge of the optical member15can be pinched between the frame16and each of the receiving plates14d(FIGS. 4 and 5). The frame16can receive the outer edge of the liquid crystal panel11from the back side and pinch the outer edge of the liquid crystal panel11between the frame16and the bezel13arranged on the front side (FIGS. 4 and 5).

Next, the LEDs17and the LED substrates18that mount the LEDs17thereon will be described in detail. As shown inFIG. 7,FIG. 8andFIG. 10, each of the LED17is formed by sealing an LED chip on a substrate portion fixedly attached to the LED substrate18with a resin material. The LED chip mounted on the substrate portion has one type of main light-emitting wavelength, and specifically, emits only blue light. Meanwhile, phosphors converting blue light emitted by the LED chip into white light are dispersedly mixed in the resin material sealing the LED chip. Thereby, the LED17can emit white light. This LED17is a so-called top type in which a surface on the side opposite to the mounting surface of the LED substrate18acts as a light-emitting surface17a. An optical axis LA in the LED17substantially corresponds to the Z-axis direction (the direction orthogonal to the liquid crystal panel11and a main plate surface of the optical member15.) Light emitted from the LEDs17extends radially to some extent about the optical axis LA within a predetermined angular range in a three-dimensional way, and has a higher directivity than light from a cold cathode tube. That is, the light emission intensity of the LED17becomes remarkably high in a direction along the optical axis LA and rapidly lowers as inclination angle relative to the optical axis LA is larger.

Each of the LED substrates18has, as shown inFIG. 10, a base member shaped like a rectangle in a plan view, and is stored in the chassis14while extending along the bottom plate14ain the state where its long-side direction corresponds to the X-axis direction and its short-side direction corresponds to the Y-axis direction (FIG. 3). The base member of the LED substrate18is made of metal such as aluminum material that is the same as the material for the chassis14, and has a surface on which a wiring pattern formed of a metal film such as a copper foil is formed via an insulating layer. Insulating materials such as ceramic can be used as the material for the base member of the LED substrate18. As shown inFIG. 7,FIG. 8andFIG. 10, the LEDs17having the above-mentioned configuration are mounted on a surface facing the front side (surface facing the optical member15side) among surfaces of the base member of the LED substrate18. The plurality of LEDs17is linearly arranged along the long-side direction of the LED substrates18(X-axis direction) in parallel, and are serially connected according to the wiring pattern formed on the LED substrates18. The alignment pitch of the LEDs17is almost constant, that is, the LEDs17are arranged at regular intervals. A connector portion18ais provided at both ends of each the LED substrates18in the long-side direction.

As shown inFIG. 3, the plurality of LED substrates18having the above-mentioned configuration is arranged in the chassis14in each of the X-axis direction and the Y-axis direction so that the LED substrates18are aligned in the long-side direction and the short-side direction in parallel. That is, the LED substrates18and the LEDs17mounted thereon are arranged in the chassis14in a matrix having the X-axis direction (the long-side direction of the chassis14and the LED substrate18) as a row direction and the Y-axis direction (the short-side direction of the chassis14and the LED substrate18) as the column direction. Specifically, the three LED substrates18in the X-axis direction×the nine LED substrates18in the Y-axis direction, that is, 27 LED substrates18in total are arranged in the chassis14in parallel. In this embodiment, two types of LED substrates18having different long-side dimensions and the number of mounted LEDs17are used. Specifically, a six-mounted type of the LED substrate18that mounts the six LEDs17thereon and has a relatively long long-side dimension and a five-mounted type of the LED substrate18that mounts the six LEDs17thereon and has a relatively short long-side dimension are used as the LED substrates18, and the six-mounted type of the LED substrate18is arranged at each end of the chassis14in the X-axis direction and the five-mounted type of the LED substrate18is arranged at the center in the same direction. As described above, the LED substrates18aligned in one row in the X-axis direction are electrically connected to each other by fitting the adjacent connector portions18awith each other, and the connector portions18alocated at both ends of the chassis14in the X-axis direction are each electrically connected to an external control circuit not shown. Thereby, the LEDs17arranged on the LED substrate18forming one row are serially connected to one another, so that lighting-on and off of the lot of LEDs17contained in the one row can be controlled together by one control circuit, which enables reduction in costs. Even the different types of LED substrates18having different long-side dimensions and the number of mounted LEDs17have the substantially identical short-side dimension and alignment pitch of the LEDs17.

By preparing plural types of LED substrates18having different long-side dimensions and the number of mounted LEDs17and appropriately using the different types of LED substrates18in combination, following effects can be obtained. That is, plural types of liquid crystal display device10having different screen sizes can be manufactured by appropriately changing the appropriateness of use of each type of LED substrate18and the number of LED substrates18of each type according to each screen size, and as compared to the case where a dedicated LED substrate having the same long-side dimension as the long-side dimension of the chassis14is prepared for each screen size, the number of types of necessary LED substrates18can be greatly reduced, which enables reduction in costs. Specifically, by adding an eight-mounted type LED substrate that mounts eight LEDs17thereon to the above-mentioned two types of LED substrates18(the five-mounted type and the six-mounted type) and appropriately using the three types of LED substrates18in combination, each of the liquid crystal display devices10having the screen size of 26 inches, 32 inches, 37 inches, 40 inches, 42 inches, 46 inches, 52 inches and 65 inches can be easily manufactured.

The diffuser lenses19are made of a synthetic resin material (e.g. polycarbonate and acrylic) that is substantially transparent (highly light transmissive) and has a higher refractive index than air. As shown inFIG. 7,FIG. 8andFIG. 11, the diffuser lenses19each have a predetermined thickness, are formed to be substantially circular in a plan view, and are attached so as to cover the respective LEDs17from the front side of the LED substrate18, that is, to overlap the respective LEDs17in a plan view. The diffuser lenses19can emit highly directive light from the LEDs17while diffusing the light. That is, since directivity of the light emitted from the LEDs17is reduced through the diffuser lenses19, even when the interval of the adjacent LEDs17is set large, a region between the LEDs17is hard to be visually recognized as a dark place. Thereby, the number of installed LEDs17can be reduced. Each diffuser lens19is located to be substantially concentric with each LED17in a plan view. Each diffuser lens19has sufficiently larger dimensions in the X-axis direction and in the Y-axis direction than each LED17. Although the diffuser lens19has a smaller dimension in the X-axis direction than the LED substrate18, the diffuser lens19has a larger dimension Y-axis direction than the LED substrate18. Accordingly, both ends of the diffuser lens19in the Y-axis direction each protrude outward by a predetermined dimension from the LED substrate18in the Y-axis direction.

In each of the diffuser lenses19, a surface that faces the back side and is opposite to the LED substrate18is a light incidence surface19aon which light from the LED17is incident, while a surface that faces the front side and is opposite to the optical member15is a light emitting surface19b. As shown inFIGS. 7 and 8, the light incidence surface19aextends in parallel to a plate surface of the LED substrate18(the X-axis direction and the Y-axis direction) as a whole, but has an inclined surface obtained by forming a light incidence-side concave portion19cin a region where the light incidence surface19aand the LED17overlap each other in a plan view. The light incidence-side concave portion19cis substantially conical, is located to be almost concentric with the diffuser lens19and is opened toward the back side, that is, the LED17. The light incidence-side concave portion19chas the largest diameter at its opened end facing the LED17, which is larger than the diameter of the LED17, and becomes smaller toward the front side in diameter continually and gradually, and finally becomes the smallest at its end of the front side. The light incidence-side concave portion19chas a substantially inverted V-shaped cross section and a circumferential surface thereof is inclined relative to the Z-axis direction. The inclined surface is inclined so that the end of the front side crosses the optical axis LA of the LED17. Accordingly, light emitted from the LED17and entering into the light incidence-side concave portion19cis incident into the diffuser lens19through the inclined surface. At this time, the incident light is refracted away from the center, that is, with a wide angle, by an inclined angle of the inclined surface relative to the optical axis LA and is incident into the diffuser lens19.

Attachment shaft portions19dthat protrude toward the LED substrate18and serve as attachment structure of the diffuser lens19to the LED substrate18are provided at positions outer of the light incidence-side concave portion19cin the radial direction, on the light incidence surface19ain the diffuser lens19. The three attachment shaft portions19dare located closer to an outer edge than the light incidence-side concave portion19cin the diffuser lens19, and a line connecting the attachment portions is substantially equilateral-triangular in a plan view. By fixing each of front ends of the attachment shaft portions19dto the LED substrate18with an adhesive or the like, the diffuser lens19can be fixedly attached to the LED substrate18. The diffuser lens19is fixed to the LED substrate18through the attachment shaft portions19dso as to have a predetermined gap between the light incidence surface19aand the LED substrate18. This gap allows incidence of light from space outer of the diffuser lens19in a plan view. In the above-mentioned attachment state, a front end of the LED17protruding from the LED substrate18enters into the light incidence-side concave portion19c.

The light emitting surface19bin the diffuser lens19is shaped like a substantially flat spherical surface. Thereby, the diffuser lens19can emit light while refracting the light on an interface with an external air layer in a direction away from the center, that is, with a wide angle. A light-emitting side concave portion19eis formed in a region where the light emitting surface19boverlaps the LED17in a plan view. The light-emitting side concave portion19eis substantially bowl-like and is shaped like a substantially flat sphere having a circumferential surface inclined downward toward the center. An angle that a tangent line to the circumferential surface of the light-emitting side concave portion19eforms with the optical axis LA of the LED17is set to be larger than an angle that the inclined surface of the light incidence-side concave portion19cforms with the optical axis LA. The region where the light emitting surface19boverlaps the LED17in a plan view receives extremely larger light amount from the LED17than the other region and therefore, its brightness tends to locally become high. However, by forming the light-emitting side concave portion19ein the region, it becomes possible to emit most of light from the LED17while refracting the light with a wide angle, or reflect a part of the light from the LED17toward the LED substrate18. Thereby, it is possible to prevent the brightness of the region where the light emitting surface19boverlaps the LED17from locally becoming high, which is suitable for prevention of uneven brightness.

Next, the reflection sheet21will be described. The reflection sheet21is constituted of a first reflection sheet22that covers the substantially entire range of the inner surface of the chassis14and a second reflection sheet23that covers each of the LED substrates18. Both the reflection sheets22,23each are made of synthetic resin and have a white surface with excellent light reflectance. Both the reflection sheets22,23extend along the bottom plate14a(the LED substrate18) in the chassis14.

First, the first reflection sheet22will be described. As shown inFIG. 3, most of the first reflection sheet22on the center side, which extends along the bottom plate14aof the chassis14, is a body portion22a. A lens insertion hole22bthat can insert each LED17arranged in the chassis14as well as each diffuser lens19covering the LED17thereinto is formed through the body portion22a. The plurality of lens insertion holes22bis arranged in parallel at positions where the holes22boverlap the LEDs17and diffuser lenses19on the body portion22ain a plan view in a matrix. As shown inFIG. 6, each lens insertion hole22bis circular in a plan view and has a larger diameter than the diffuser lens19. Thereby, when the first reflection sheet22is installed in the chassis14, the diffuser lenses19can be inserted into the respective lens insertion holes22birrespective of presence or absence of dimensional error. Since the first reflection sheet22covers regions between adjacent diffuser lenses19and regions on the outer circumferential side in the chassis14as shown inFIG. 3, light toward each of the regions can be reflected toward the optical member15. Further, as shown inFIGS. 4 and 5, outer circumferential portions of the first reflection sheet22rise so as to cover the side plates14cand the receiving plates14dof the chassis14, and portions placed on the receiving plates14dare sandwiched between the chassis14and the optical member15. A portion connecting the body portion22aof the first reflection sheet22to each of the portions placed on the receiving plates14dis inclined.

Meanwhile, the second reflection sheet23has, as shown inFIG. 11, the almost same appearance as the LED substrate18, that is, is rectangular in a plan view. As shown inFIGS. 7 and 8, the second reflection sheet23is arranged so as to overlap the front side surface of the LED substrate18, and is opposite to the diffuser lens19. That is, the second reflection sheet23is interposed between the diffuser lens19and the LED substrate18. Accordingly, light returned from the diffuser lens19to the LED substrate18and light entering from space outer of the diffuser lens19in a plan view into space between the diffuser lens19and the LED substrate18can be reflected toward the diffuser lens19by the second reflection sheet23again. As a result, light utilization efficiency can be enhanced, thereby increasing brightness. In other words, even when the number of installed LEDs17is reduced to cut costs, sufficient brightness can be obtained.

As shown inFIG. 11, the second reflection sheet23has the almost same long-side dimension as the LED substrate18and has a larger short-side dimension than the LED substrate18. Further, as shown inFIGS. 6 and 8, the short-side dimension of the second reflection sheet23is set to be larger than the diameter of the diffuser lens19and the lens insertion hole22bof the first reflection sheet22. Accordingly, the edge of the lens insertion hole22bof the first reflection sheet22can be placed on the second reflection sheet23on the front side. Thereby, the first reflection sheet22and the second reflection sheet23are continuously arranged in the chassis14without any gap in a plan view, so that the chassis14or the LED substrate18is hardly exposed from the lens insertion hole22btoward the front side. Therefore, light in the chassis14can be efficiently reflected toward the optical member15, which is extremely preferable for improvement of brightness. LED insertion holes23athat insert the respective LEDs17therethrough and shaft portion insertion holes23bthat insert the respective attachment shaft portions19dof the diffuser lens19therethrough are formed in the second reflection sheet23at overlapping positions in a plan view.

Subsequently, the holding member20will be described. The holding member20includes two types: a complex function-type holding member20B having both a holding function of holding the LED substrate18and a supporting function of supporting the optical member15, and a single function-type holding member20A having the holding function and no supporting function. Hereinafter, when the holding member20is discriminated, a subscript A is added to the single function-type and a subscript B is added to the complex function-type. When the holding member20is collectively called without being discriminated, no subscript is added to the reference numeral.

First, arrangement of the holding member20in the chassis14will be described. As shown inFIG. 3, multiple holding members20are arranged on the bottom plate14aof the chassis14. Describing in detail, given that the X-axis direction (the long-side direction of the chassis14and the LED substrate18) is the row direction and the Y-axis direction (the short-side direction of the chassis14and the LED substrate18) in the bottom plate14a, the holding members20are arranged in the row and column directions (arranged in a matrix). Each of the holding members20is located at a position where the holding member overlaps each LED substrate18in a plan view and between adjacent diffuser lenses19(LEDs17). Accordingly, the holding members20are arranged like the above-mentioned diffuser lenses19and the LEDs17. Since one holding member20is arranged in a region between the adjacent diffuser lenses19(LEDs17) on the LED substrate18, the diffuser lenses19(LEDs17) and the holding members20are alternately arranged in the substantially X-axis direction. Specifically, the four holding members20are attached to each LED substrate18. On the six-mounted type of LED substrate18, the holding members20are arranged at positions other than the central position in the long-side direction in the regions between the adjacent diffuser lenses19(LEDs17), and in the five-mounted type of LED substrate18, the holding members20are arranged in all of the regions between the adjacent diffuser lenses19(LEDs17).

As shown inFIG. 3, the a lot of holding members20arranged as described above are the single function-type holding members20A except for later-described two complex function-type holding member20B. The two complex function-type holding member20B each are arranged at a position that is central in the short-side direction and closer to the center than an outer end in the long-side direction in the chassis14. Describing the arrangement in the long-side direction in detail, the complex function-type holding members20B are arranged symmetrically about the central LED substrate18among the three LED substrates18aligned in parallel in the X-axis direction.

Subsequently, specific configuration of the holding member20will be described. Although two types of holding members20exist as described above, the holding members20have mainly a common structure and the common structure will be described first. The holding member20is made of synthetic resin such as polycarbonate, and has a white surface with excellent light reflectance. The holding member20is substantially circular in a plan view as a whole. As shown inFIGS. 7 and 9, the holding member20includes a body portion24along the bottom plate14aof the chassis14and the plate surface of the LED substrate18, and a fixed portion25that protrudes from the body portion24toward the back side, that is, the chassis14and is fixed to the chassis14. The holding member20is shaped symmetrically about a central axis in the Z-axis direction as a whole.

As shown inFIGS. 12 to 15, the body portion24is substantially circular in a plan view, and is shaped like an almost straight plate extending in the X-axis direction and the Y-axis direction. As shown inFIG. 6, the body portion24has the almost same diameter as the short-side dimension (dimension in the Y-axis direction) of the LED substrate18. The body portion24is attached to the LED substrate18so as to overlap the LED substrate18in a plan view, thereby holding the LED substrate18between the body portion and the bottom plate14aof the chassis14. Since the body portion24is attached in the state where the reflection sheets22,23are arranged beforehand on the front side of the LED substrate18, the reflection sheets22,23together with the LED substrate18can be sandwiched (FIGS. 7 and 9).

Describing in detail, as shown inFIG. 6, the body portion24is arranged so that its center corresponds to the center of the LED substrate18in the short-side direction. Accordingly, the body portion24can pinch the LED substrate18between the body portion and the chassis14over the entire length in the short-side direction. At this time, both outer ends of the body portion24in the Y-axis direction substantially coincide with both outer ends of the LED substrate18in the short-side direction. That is, the body portion24overlaps the LED substrate18almost entirely in a plan view, thereby being prevented from extending outside of the LED substrate18. The diameter of the body portion24is set to be smaller than the interval (alignment pitch) between the adjacent diffuser lenses19(LEDs17) in the X-axis direction. Thereby, the body portion24is arranged in a region between the adjacent diffuser lenses19(LEDs17) on the LED substrate18in the X-axis direction, that is, in a non-luminous portion of the LED substrate18and thus, does not overlap the LED17in a plan view. That is, it is possible to prevent the body portion24from disturbing light emission from the LED17. In this embodiment, since the interval between the LEDs17is made sufficiently large by using the diffuser lens19as described above, the holding member20is arranged in the space to fix the LED substrate18.

As shown inFIG. 9, the fixed portion25can be engaged with the bottom plate14aof the chassis14through the attachment holes14eformed at the attachment position of the holding member20on the bottom plate14a. Hereinafter, detailed configuration of the fixed portion25will be described. As shown inFIGS. 13 and 15, the fixed portion25is arranged on the center side of the body portion24. Describing in detail, the fixed portion25is arranged to be concentric with the body portion24. The fixed portion25protrudes, as shown inFIG. 9, from the back side surface of the body portion24(surface opposite to the chassis14) toward the back side, and a grooved portion25cis formed at a front end of the fixed portion25to form elastic engaged portions25b. In other words, the fixed portion25is constituted of a bottom portion25aprotruding from the body portion24toward the back side, and the elastic engaged portions25bprotruding a protruding front end of the bottom portion25afurther toward the back side. The bottom portion25ais substantially cylindrical and has a diameter that is smaller than that of the attachment holes14eof the chassis14so as to allow insertion into the attachment holes14e.

As shown inFIGS. 13 and 15, the elastic engaged portions25bare four portions divided by the substantially crosswise grooved portion25cin a plan view. Each of the elastic engaged portions25bcantilevers as shown inFIGS. 7 and 9, and is elastically deformable using a protruding bottom end part of the bottom portion25aas a fulcrum while forming a hollow into the grooved portion25c. That is, the grooved portion25cserves as flexure space for the elastic engaged portions25b. Engaging portion25dswelling outward, that is, to the side opposite to the grooved portion25c, are provided on outer side surfaces of the elastic engaged portions25b. Each of the engaging portions25dprotrudes outward further than the outer circumferential surface of the bottom portion25a, and the diameter of the fixed portion25at the swelled ends (the largest diameter) is larger than the diameter of the attachment hole14e. In other words, the swelled ends of the engaging portion25dare located outer of the inner circumferential surface of the attachment holes14e. Accordingly, the engaging portions25dcan be engaged with the edge of the attachment hole14eof the chassis14, that is, the part adjacent to the fixed portion25in the chassis14, from the back side. When the fixed portion25is inserted into the attachment hole14eof the chassis14in this manner, each elastic engaged portion25bpasses through the attachment hole14eand is elastically engaged with the edge of the attachment hole14efrom the back side. In this manner, the holding member20can be fixedly attached to the chassis14. The plurality of attachment holes14eis arranged in parallel at the attachment positions of the holding members20on the bottom plate14aof the chassis14in the X-axis direction and the Y-axis direction in a matrix.

As shown inFIG. 6, the body portion24provided with the fixed portion25entirely overlaps the LED substrate18in a plan view. Accordingly, since the fixed portion25also overlaps the LED substrate18in a plan view, a through hole18bthat passes the fixed portion25therethrough is formed in the LED substrate18. As shown in FIG.10, the through hole18bis located between the adjacent LEDs17(diffuser lenses19) on the LED substrate18, that is, at the non-overlapping position with the LED17(diffuser lens19) in a plan view. The through hole18bis elongated in the X-axis direction in a plan view, and its both short-side edges are formed to be a circular arc. The through hole18bhas a short-side dimension that allows insertion of the fixed portion25and a long-side dimension that is larger than the short-side dimension. As shown inFIGS. 7 and 9, since the through hole18bpasses through the LED substrate18in the Z-axis direction, the fixed portion25can pass through the LED substrate18. Accordingly, the LED substrate18can be positioned in the X-axis direction and the Y-axis direction by the fixed portion25passing through the through hole18b. As shown inFIG. 7,FIG. 9andFIG. 11, communicating holes22c,23cthat communicate with the through hole18band can pass the fixed portion25therethrough are formed at positions overlapping with the through hole18bin a plan view on the reflection sheets22,23sandwiched between the body portion24and the LED substrate18, respectively.

As shown inFIGS. 7 and 9, the body portion25of the holding member20according to this embodiment is provided with contact portions26that protrude toward the back side, that is, toward the reflection sheet21(LED substrate18, chassis14) and are contacted with the reflection sheet21. The contact portions26can contact the first reflection sheet22of the reflection sheet21to directly press the first reflection sheet22from the front side and indirectly press the second reflection sheet23and the LED substrate18from the front side via the first reflection sheet22. Since the contact portions26are partially protruded from the back side surface (surface opposite to the first reflection sheet22) of the body portion24, as compared to the case where the entire back side surface of the body portion is in contact with the first reflection sheet22, the contact area with the first reflection sheet22is reduced. In the state where the contact portions26are in contact with the first reflection sheet22, the back side surface of the body portion24floats from the first reflection sheet22in a non-contact state, and a gap C corresponding to the protruding dimension of the contact portion26is ensured between the back side surface of the body portion24and the front side surface of the first reflection sheet22.

As shown inFIGS. 13 and 15, the contact portions26are located at a position in the body portion24away from the fixed portion25, specifically, at an outer edge of the body portion24. It means that the contact portions26are arranged at positions that are farthest from the fixed portion25located at the center of the body portion24. A part of the body portion24according to this embodiment from the fixed portion25to the contact portions26has predetermined elasticity, and is elastically deformable according to stress applied. Two pairs of the contact portions26are each located at the body portion24across the fixed portion25, that is, four contact portions26in total are arranged. Describing in detail, the contact portions26are arranged at body portion24at intervals of about 90 degrees, that is, on two straight lines that pass the center of the body portion24and the fixed portion25and are orthogonal to each other. In other words, the contact portions26are located at the body portion24to be symmetrical about the fixed portion25. Accordingly, the distance between the fixed portion25and each of the contact portions26is equal. Each contact portion26is point when viewing the plate surface of the body portion24in a plan view. Thus, since contact points of the holding member20with the first reflection sheet22are dispersed on the plate surface of the body portion24at regular intervals in a well-balanced manner, the holding member20can be stably supported on the first reflection sheet22without any unsteadiness (FIG. 6).

As shown inFIGS. 7 and 9, each contact portion26is substantially hemispherical as a whole, and its circumferential surface (contact surface with the first reflection sheet22) is a spherical surface. Accordingly, each contact portion26is in point contact with the first reflection sheet22. Thereby, the contact area of each contact portion26with the first reflection sheet22becomes minimum.

Next, difference between the two types of holding members20in configuration will be described. As shown inFIG. 9, an inclined surface24ais formed on an outer circumferential end surface of the body portion24in the single function-type holding member20A. The inclined surface24ais inclined downward from the center toward the outer end of the body portion24, thereby eliminating or reducing possible step from the first reflection sheet22. As a result, the outer circumference (boundary with the reflection sheet21) of the body portion24is hard to be visually recognized as uneven brightness through the optical member15. Although not shown, the inclined surface24amay be provided at the complex function-type holding member20B.

As shown inFIGS. 7 and 9, the complex function-type holding member20B includes a supporting portion27that protrudes the body portion24toward the front side and can support the optical member15from the back side. The supporting portion27is conical as a whole. Describing in detail, the supporting portion27has a circular cross section cut along the plate surface of the body portion24and is tapered so that its diameter becomes smaller from a protruding bottom end toward a protruding front end. The supporting portion27can contact the diffuser15alocated closest to the back side (LED17side) in the optical member15, thereby supporting the diffuser15aat a predetermined position. That is, the supporting portion27can restrict positional relationship between the optical member15and the LED17in the Z-axis direction (the direction orthogonal to the surface of the optical member15) to be constant.

The outer diameter of a protruding bottom end of the supporting portion27is set to be smaller than both the short-side dimension of the body portion24and the short-side dimension of the LED substrate18. That is, the supporting portion27is point in a plan view, while the body portion24is sheet-like in a plan view over a wider scope than the supporting portion27. The protruding dimension of the supporting portion27is almost equal to the distance between the front side surface of the body portion24and the back side surface of the diffuser15a, which is almost straight in the X-axis direction and the Y-axis direction. Accordingly, the supporting portion27is in contact with the almost straight diffuser15a. The protruding front end of the supporting portion27as the contact place with the diffuser15ais rounded. Since the supporting portion27is an only portion in the complex function-type holding member20B, which protrudes from the body portion24toward the front side, in attaching the complex function-type holding member20B to the chassis14, the operator can use the supporting portion27as an operating portion. Thereby, attachment workability of the complex function-type holding member20B can be improved.

As shown inFIGS. 14 and 15, the supporting portion27is located substantially at the center of the body portion24. That is, the supporting portion27is located at such a position as to overlap the fixed portion25arranged on the back side in a plan view. Describing in more detail, the supporting portion27and the fixed portion25are located at such a position as to be concentric with each other in a plan view. With such arrangement, in attaching the complex function-type holding member20B to the chassis14, when the operator uses the supporting portion27as the operating portion, the operator can easily know the position of the fixed portion25hidden on the back side by visually recognizing the supporting portion27exposed on the front side. Accordingly, workability in inserting the fixed portion25into the communicating holes22c,23c, through hole18b, and attachment hole14ecan be improved.

This embodiment has the above-mentioned configuration, and its action will be described. The liquid crystal display device10shown inFIGS. 4 and 5is manufactured by separately manufacturing the liquid crystal panel11and the backlight unit12and assembling them by use of the bezel13or the like. Especially, the assembling operation in manufacturing the backlight unit12will be described in detail.

In this embodiment, prior to assembling of each constituent to the chassis14, LEDs17, the second reflection sheet23and the diffuser lenses19are attached to the LED substrate18. Describing in detail, first, as shown inFIG. 10, after the LEDs17are mounted at predetermined positions on the LED substrate18, the second reflection sheet23is attached to cover the front side. At this time, the LEDs17on the second reflection sheet23are inserted into the respective LED insertion holes23a, and the through holes18b,23cin the LED substrate18and the second reflection sheet23are aligned and communicated to each other. After that, as shown inFIG. 11, the diffuser lenses19are attached to the LED substrate18so as to cover the respective LEDs17. At this time, the attachment shaft portions19dof the diffuser lenses19are fixedly adhered to the LED substrate18with an adhesive through the respective shaft portion insertion holes23bin the second reflection sheet23. In this manner, a so-called light source unit U formed by uniting the LEDs17, the second reflection sheet23and the diffuser lenses19is manufactured on the LED substrate18.

Subsequently, an assembling operation of each constituent to the chassis14will be described. First, the light source units U are stored from the front side of the chassis14through the openings14band are arranged at predetermined attachment positions on the bottom plate14a. At this time, each through hole18bon the LED substrate18in each light source unit U is aligned and communicated with each attachment hole14eon the chassis14.

Here, the adjacent LED substrates18in the X-axis direction are electrically connected to each other by fitting the adjacent connector portions18awith each other. The operation of connecting the LED substrates18aligned in the X-axis direction to each other is not necessarily performed within the chassis14, and may be performed outside of the chassis14. When arrangement of all of the light source units U is completed, an operation of arranging the first reflection sheet22in the chassis14is performed. At this time, while positioning the lens insertion holes22bof the first reflection sheet22with respect to the respective diffuser lenses19in each light source unit U, the diffuser lens19are passed through the respective lens insertion holes22b(FIG. 3). When the first reflection sheet22is attached, the first reflection sheet22is placed from the front side onto almost all portions of the second reflection sheet23other than the overlapping portion with the diffuser lens19in a plan view (FIGS. 7 and 8). Especially, the edge of the lens insertion hole22bof the first reflection sheet22is entirely placed on the front side of the second reflection sheet23. Here, as shown inFIG. 16, the communicating hole22con the first reflection sheet22is aligned and communicated with the communicating hole23con the second reflection sheet23, the through hole18bon the LED substrate18and the attachment hole14eon the chassis14in the X-axis direction. After that, the assembling operation of the holding member20is performed.

In assembling the holding member20to the chassis14, for the complex function-type holding member20B of the holding member20, the supporting portion27can be used as an operating portion. With this configuration, in assembling the complex function-type holding member20B, the operator can operate the complex function-type holding member20B while holding the supporting portion27. The complex function-type holding member20B is stored from the front side of the chassis14through the opening14b, and the fixed portion25hidden across the body portion24on the back side is inserted into the corresponding communicating holes22c,23c, through the hole18band the attachment hole14e. At this time, since the supporting portion27and the fixed portion25are located so as to overlap and be concentric with each other in a plan view, the operator can easily recognize the position of the fixed portion25. Accordingly, the fixed portion25can be smoothly inserted into each of the holes14e,18b,22cand23c. Matters related to assembling to the chassis14, which are common to all holding members20including the single function-type holding member20A, will be described below.

In assembling each holding member20(including the single function-type holding member20A), when the fixed portion25is being inserted into each of the holes14e,18b,22cand23c, each elastic engaged portion25bis elastically deformed once in such a manner as to be recessed in the grooved portion25c. After that, when the fixed portion25is inserted until each elastic engaged portion25breaches the back side of the chassis14, as shown inFIGS. 7 and 9, each elastic engaged portion25belastically returns and the engaging portion25dis engaged with the edge of the attachment hole14efrom the back side. Thereby, the holding member20is prevented from being detached from the chassis14and is fixed to the attached state. In this state, the LED substrate18and the reflection sheets22,23are sandwiched together between the body portion24of the holding member20and the bottom plate14aof the chassis14.

During the process in which the holding member20returns to the attached state as described above, when each elastic engaged portion25belastically returns, each contact portion26provided at the body portion24contacts the front side surface of the first reflection sheet22. Accordingly, in the attached state, the spherical circumferential surface of each contact portion26is in point contact with the first reflection sheet22, while the back side surface of the body portion24(surface opposite to the first reflection sheet22) floats from the first reflection sheet22in the non-contact state, and the gap C corresponding to the protruding dimension of the contact portion26is held between the front side surface of the body portion24and the front side surface of the first reflection sheet22. Accordingly, the contact area of the holding member20with the first reflection sheet22is very small and as compared to the case where the entire back side surface of the body portion is in contact, the contact area is reduced. Conversely speaking, this means that the area of the non-contact part of the first reflection sheet22with the holding member20(the part that is not pressed by the holding member20) increases. In the attached state, the holding member20is stably supported by the four contact portions26located at symmetrical positions at intervals of about 90 degrees. Describing in more detail, since the contact portions26is arranged at the outer edge of the body portion24, the contact portions26are located at a position overlapping the outer edge of the LED substrate18in the short-side direction in a plan view. Accordingly, the outer edge of the LED substrate18in the short-side direction is pressed from the front side by the contact portions26. The first reflection sheet22is directly pressed by the contact portions26and the second reflection sheet23and the LED substrate18are indirectly pressed by the contact portion26through the first reflection sheet22.

Since the fixed portion25passes through the reflection sheets22,23and the LED substrate18, the reflection sheets22,23and the LED substrate18are prevented from carelessly moving in the X-axis direction and the Y-axis direction, thereby being positioned in these directions. Further, since the fixed portion25achieves fixation by passing through the attachment hole14eformed on the chassis14and mechanically engaging there, as compared to the case of adopting fixing means such as the adhesive, fixation can be achieved more easily at lower costs and the holding member20can be detached at the time of maintenance and disposal.

As shown inFIG. 3, the holding members20thus attached are arranged at different plural places in the long-side direction (X-axis direction) on each LED substrate18. Thereby, each LED substrate18can be stably held. Further, the body portion24of the holding member20is arranged so as to pass between the adjacent LEDs17(the diffuser lenses19) on the LED substrate18as shown in FIG.7, it is prevented to disturb light emitted from the LED17.

After that, the optical member15is attached to the chassis14so as to cover the openings14b. According to the specific attaching order of the optical member15, the diffuser15a, and then, the optical sheets15bare attached. The optical member15, as shown inFIGS. 4 and 5, is received by the receiving plates14dof the chassis14at its outer circumference, and is supported by the supporting portion27of the complex function-type holding member20B at its central part. Then, when the frame16is attached to the chassis14, the outer circumference of the optical member15is pinched between the frame16and the receiving plates14d. Thereby, manufacturing of the backlight unit12is completed. In assembling the manufactured backlight unit12and the liquid crystal panel11, the liquid crystal panel11is placed on the frame16and then, the bezel13is covered on the front side, and they are screwed together. Thereby, the liquid crystal panel11is pinched between the frame16and bezel13and becomes integral with the backlight unit12, resulting in that manufacturing of the liquid crystal display device10is completed.

In using the liquid crystal display device10manufactured as described above, each of the LEDs17provided in the backlight unit12is lighted and an image signal is supplied to the liquid crystal panel11, thereby displacing a predetermined image on a display screen of the liquid crystal panel11. As shown inFIGS. 7 and 8, light emitted to light each of the LEDs17is first incident on the light incidence surface19aof the diffuser lens19. At this time, most of light is incident on an inclined surface of the light incidence-side concave portion19cof the light incidence surface19aand thus, into the diffuser lens19while being refracted with a wide angle according to the inclined angle. Then, the incident light propagates in the diffuser lens19and is emitted from the light emitting surface19b. However, since the light emitting surface19bis a substantially flat spherical surface, light is emitted while being further refracted at a boundary with the external air layer with a wider angle. Moreover, since the substantially bowl-like light-emitting side concave portion19eis formed in a region where the amount of light from the LED17is the largest in the light emitting surface19b, and its circumferential surface is a substantially flat spherical surface, light can be emitted while being refracted at the circumferential surface of the light-emitting side concave portion19ewith a wide angle, or can be reflected toward the LED substrate18. Since light returned to the LED substrate18is reflected toward the diffuser lens19by the second reflection sheet23and is incident on the diffuser lens19once, high brightness can be obtained.

Since the highly directive light emitted from the LED17can be diffused with a wide angle by the diffuser lens19, in-plane distribution of the light reaching the optical member15can be made uniform. In other words, since the region between the adjacent LEDs17becomes hard to be visually recognized as the dark place by using the diffuser lens19, the interval between the LEDs17can be increased, thereby reducing the number of installed LEDs17while suppressing uneven brightness. Then, since the interval between the adjacent LEDs17can be increased by reducing the number of installed LEDs17, the holding member20can be located in the wider region, and furthermore, the holding member20can fix the LED substrate18.

Each LED17generates heat during lighting. Most of heat emitted from the LEDs17is propagated to the chassis14through the LED substrate18that mounts the LEDs17thereon, and then, is radiated to air outside of the liquid crystal display device10. Considering heat radiation efficiency at this time, as closeness between the LED substrate18and the chassis14is higher, their heat transfer property improves. Conversely, as closeness between the LED substrate18and the chassis14is lower, their heat transfer property lowers, resulting in a tendency of lower heat radiation efficiency. In this embodiment, in order to improve heat radiation efficiency, the LED substrate18is fixed to the chassis14by means of the holding member20and the following configuration is adopted. That is, since the outer edge of the LED substrate18in the short-side direction is pressed from the front side by the contact portions26of the holding member20, the LED substrate18is stably held in close contact with the chassis14. Moreover, since the holding member20has the fixed portion25at the center of the body portion24and the contact portions26at the outer edge of the body portion24, the LED substrate18is pressed by the central fixed portion25from the back side as well as by the contact portions26at the outer edge from the front side and thus, is stably held in a well-balanced manner. Further, since the contact portions26are located at the body portion24at regular intervals, the LED substrate18can be stably pressed in a well-balanced manner. As described above, since the LED substrate18is stably fixed to the chassis14in close contact with each other by means of the holding member20, heat transfer property to the chassis14is extremely high and therefore, heat can be efficiently radiated. Accordingly, since temperature inside the backlight unit12is hard to become high, light emission efficiently of the LEDs17is prevented from lowering and thus, high brightness can stably be obtained.

In using the liquid crystal display device10as described above, since each of the LEDs17in the backlight unit12is lighted on or off, internal temperature environment changes and thus, each constituent of the liquid crystal display device10may be thermally expanded or thermally contracted. In the case where the first reflection sheet22and the second reflection sheet23among the constituents are thermally expanded or thermally contracted, when local deformation such as wrinkle or flexure is generated, unevenness is easy to occur in reflected light and uneven brightness occurs in light emitted from the backlight unit12, possibly exerting a negative effect on display quality. Further, in the case where the LED substrate is thermally expanded or thermally contracted, when local deformation such as warp and flexure is generated, contact failure occurs in the connector portions18a, resulting in deficiency in controlling of lighting of the LED17. Such local deformation that can occur in the reflection sheets22,23and the LED substrate18is easy to occur in proportion to magnitude of the pressing forces acted by the chassis14and the holding member20and the pressed area (contact area), and in order to suppress such local deformation, it is preferable to reduce the pressing forces or the pressed area.

Thus, in this embodiment, as shown inFIG. 9, by providing the contact portions26at the holding member20and bringing the contact portions26of the holding member20into point contact with the first reflection sheet22, the contact area with the first reflection sheet22is reduced. When the contact area is reduced, in the reflection sheets22,23and the LED substrate18, a part that is pressed by the holding member20(part overlapping with the contact points of the contact portions26in a plan view) decreases and a part that is not pressed by the holding member20(part that is not in overlap with the contact points of the contact portions26in a plan view) increases. The part pressed by the holding member20is relatively easy to be restricted in expansion or contraction due to thermal expansion or thermal contraction (the degree of flexibility in expansion or contraction is low), while the part that is not pressed by the holding member20is relatively easy to be allowed in expansion or contraction due to thermal expansion or thermal contraction (the degree of flexibility in expansion or contraction is high). In this embodiment, since the unpressed area is increased, the reflection sheets22,23and the LED substrate18as a whole are easy to thermally expand or contract, and flexure or warp that can be caused by expansion or contraction is preferably absorbed by the unpressed part. As a result, flatness as a whole is kept and thus, local flexure or warp in the reflection sheets22,23and the LED substrate18is suppressed.

Moreover, the contact portions26are located at a position in the body portion24away from the fixed portion25. The contact portions26apply the pressing forces to the reflection sheets22,23and the LED substrate18from the front side (body portion24), while the fixed portion25applies the pressing forces to the reflection sheets22,23and the LED substrate18from the back side (chassis14side). Accordingly, by locating the contact portions26and the fixed portion25so as to be shifted (offset) from each other in a plan view, in the reflection sheets22,23and the LED substrate18, the position where the pressing forces are applied from the front side (positions of the contact portions26) and the positions where the pressing forces are applied from the back side (position of the engaging portion25d) are similarly shifted from each other. Accordingly, it is prevented that stress applied to the reflection sheets22,23and the LED substrate18from the front side and the back side is concentrated. Thus, since the pressing forces exerted on the reflection sheets22,23and the LED substrate18are prevented from increasing, the phenomenon that the degree of flexibility in expansion or contraction of the part pressed by the holding member20becomes extremely low can be prevented, and the degree of flexibility in expansion or contraction of the reflection sheets22,23and the LED substrate18can be improved.

Furthermore, by locating the contact portions26at a position in the body portion24away from the fixed portion25, following functions and effects can be obtained. That is, when dimensional error occurs in manufacturing of the holding member20, for example, when the protruding dimension of each contact portion26from the body portion24exceeds a set value or the length of the fixed portion25falls below a set value, the pressing forces exerted on the reflection sheets22,23and the LED substrate18may excessively become large (than required). Then, in this embodiment, since some elasticity is imparted to the part of the body portion24from the fixed portion25to each contact portion26, as shown inFIG. 17, the part of the body portion24from the fixed portion25to each contact portion26is elastically deformed to accommodate possible increasing pressing forces. Thereby, it can be prevented that excessive pressing forces are applied from the contact portions26to the reflection sheets22,23and the LED substrate18. Thus, the degree of flexibility in expansion or contraction of the reflection sheets22,23and the LED substrate18can be ensured.

As described above, the backlight unit12according to this embodiment includes the LEDs17as light sources, the chassis14that stores the LEDs17, the reflection sheet21and the LED substrate18as the extending members extending along the inner surface of the chassis14and the holding member20that sandwiches the reflection sheet21and the LED substrate18between the holding member20and the chassis14and is fixed to the chassis14, and the holding member20is provided with the contact portions26that protrude toward the reflection sheet21and the LED substrate18and are in contact with the reflection sheet21and the LED substrate18.

With this configuration, when the holding member20is fixed to the chassis14, the reflection sheet21and the LED substrate18are held with being sandwiched between the holding member20and the chassis14. Since the holding member20is provided with the contact portions26protruding toward the reflection sheet21and the LED substrate18, and the contact portions26are in contact with the reflection sheet21and the LED substrate18, as compared to the case where the entire opposite surface of the holding member to the reflection sheet21contacts the reflection sheet21, the contact area of the holding member20with the reflection sheet21can be reduced. Conversely speaking, since the reflection sheet21and the LED substrate18are not in contact with the holding member20, the area of the part that is not pressed by the holding member20increases. The unpressed part is easier to expand or contract when thermal expansion or thermal contraction occurs due to change in the thermal environment than the part that is in contact with the holding member20and is pressed by the holding member20. When the area of the unpressed part increases, the degree of flexibility in expansion or contraction of the reflection sheet21and the LED substrate18as a whole is improved, thereby preventing local deformation such as flexure or warp due to expansion or contraction.

By reducing the contact area of the holding member20with the reflection sheet21as described above, the thermally expanded or contacted reflection sheet21and LED substrate18can easily slide with respect to the contact parts (contact portions26) of the holding member20and thus, the degree of flexibility in expansion or contraction of the reflection sheet21and the LED substrate18can be improved.

The holding member20includes the body portion24that sandwiches the reflection sheet21and the LED substrate18between the body portion24and the chassis14and the fixed portion25that protrudes from the body portion24toward the chassis14and is fixed to the chassis14, and the contact portions26are provided at the body portion24. With this configuration, when the fixed portion25is fixed to the chassis14, the reflection sheet21and the LED substrate18, which are sandwiched between the body portion24and the chassis14, are preferably held. At this time, the contact portions26are in contact with the reflection sheet21, thereby preventing contact of the entire opposite surface of the body portion24to the reflection sheet21.

The contact portions26are located at a position in the body portion24away from the fixed portion25. With this configuration, when the holding member20is fixed to the chassis14, pressing forces from both the chassis14and the body portion24act on the reflection sheet21and the LED substrate18. Here, the position in the reflection sheet21and the LED substrate18, on which the pressing force from the chassis14acts, and the position in the reflection sheet21and the LED substrate18, on which the pressing force from the body portion24acts, depend on positional relationship between the contact portion26and the fixed portion25. In this embodiment, since the contact portions26are located at a position in the body portion24away from the fixed portion25, the position in the reflection sheet21and the LED substrate18, on which the pressing force from the chassis14acts, and the position in the reflection sheet21and the LED substrate18, on which the pressing force from the body portion24acts, are shifted (offset) from each other in a plan view. Accordingly, for example, as compared to the case where the positions of the reflection sheet21and the LED substrate18, on which the pressing forces act, are the same in a plan view, stress exerted on the reflection sheet21and the LED substrate18can be dispersed, and stress concentration can be mitigated. Thereby, the degree of flexibility in expansion or contraction of the reflection sheet21and the LED substrate18can be improved.

In the case where the dimensional error occurs in manufacturing of the holding member20, for example, when the protruding dimension of the contact portions26from the body portion24exceeds the set value, the pressing forces exerted on the reflection sheet21and the LED substrate18may become excessively large. Even in such case, since the contact portions26are located at a position in the body portion24away from the fixed portion25, the part of the body portion24from the fixed portion25to the contact portions26is elastically deformable to accommodate the possibly increasing pressing forces. As a result, it can be prevented that excessive pressing forces are applied from the contact portions26to the reflection sheet21and the LED substrate18and thus, the degree of flexibility in expansion or contraction of the reflection sheet21and the LED substrate18can be ensured.

The fixed portion25is located at the center of the body portion24, while the contact portions26are located at outer edge of the body portion24. With this configuration, by locating the fixed portion25at the center of the body portion24, the holding member20can be stably fixed to the chassis14. In addition, since the distance between the fixed portion25and each contact portion26can be ensured to be maximum by locating the contact portions26at the outer edge of the body portion24, stress concentration can be mitigated more suitably and thus, the degree of flexibility in expansion or contraction of the reflection sheet21and the LED substrate18can be improved further. Further, since the body portion24is elastically deformable more easily by ensuring the distance between the fixed portion25and each contact portion26, the range for accommodating the dimensional error occurring in manufacturing of the holding member20can be increased and thus, the degree of flexibility in expansion or contraction of the reflection sheet21and the LED substrate18can be ensured more stably.

The fixed portion25is located at the center of the body portion24, while at least a pair of contact portions26are located at the body portion24across the fixed portion25. With this configuration, by locating the fixed portion25at the center of the body portion24, the holding member20can be stably fixed to the chassis14. In addition, since at least a pair of contact portions26are located across the fixed portion25, pressing forces can be exerted on the reflection sheet21and the LED substrate18in a well-balanced manner and thus, the reflection sheet21and the LED substrate18can be properly held while improving the degree of flexibility in expansion or contraction of the reflection sheet21and the LED substrate18.

The contact portions26are located at positions symmetrical with each other about the fixed portion25. With this configuration, pressing forces can be exerted on the reflection sheet21and the LED substrate18in a more balanced manner.

The fixed portion25is fixed to the chassis14through the reflection sheet21and the LED substrate18. With this configuration, the reflection sheet21and the LED substrate18can be positioned in the direction along the plate surface by the fixed portion25passing through the reflection sheet21and the LED substrate18.

The fixed portion25passes through the reflection sheet21, the LED substrate18and the chassis14, and is engaged with the chassis14from the side opposite to the reflection sheet21and the LED substrate18. With this configuration, by engaging fixed portion25passing through the reflection sheet21, the LED substrate18and the chassis14with the chassis14, the holding member20, the reflection sheet21and the LED substrate18can be fixed and thus, fixation can be easily achieved at low costs without using other fixing means such as adhesive.

The optical member15is located opposite to each LED17, and the body portion24in the complex-type holding member20B is provided with the supporting portion27that protrudes toward the optical member15and supports the optical member15. With this configuration, the complex function-type holding member20B for fixing the reflection sheet21and the LED substrate18can also have a function of supporting the optical member15.

The fixed portion25and the supporting portion27are located at a position overlapping with each other in a plan view. With this configuration, when the operator attaches the complex function-type holding member20B while holding the supporting portion27, the position of the fixed portion25can be easily recognized, which is excellent in workability.

The fixed portion25and the supporting portion27are located at such a position as to be concentric with each other. With this configuration, workability is more excellent.

The contact portions26each are point in a plan view. With this configuration, the contact portions26are in point contact with the reflection sheet21, the contact area can be reduced to the minimum and thus, the degree of flexibility in expansion or contraction of the reflection sheet21and the LED substrate18can be improved.

The contact surface of each contact portion26with the reflection sheet21and the LED substrate18is formed of a curved surface. With this configuration, the reflection sheet21can easily slide with respect to the contact portions26and thus, the degree of flexibility in expansion or contraction can be improved further.

The contact surface of each contact portion26is formed of a spherical surface. With this configuration, the reflection sheet21and the LED substrate18can slide with respect to the contact portions26more easily and thus, the degree of flexibility in expansion or contraction can be improved further.

The extending member is the LED substrate18having the LEDs17. With this configuration, since the degree of flexibility in expansion or contraction caused by thermal expansion or thermal contraction of the LED substrate18is improved, a contact failure is hard to occur in a connection place with an external circuit or the like, and deficiency in controlling lighting of the LED17can be prevented.

The plurality of LED17is arranged on the LED substrate18in parallel. With this configuration, the plurality of LED17can be efficiently arranged on the LED substrate18, which is suitable for higher brightness.

The holding member20is arranged between the adjacent LEDs17. With this configuration, space between the adjacent LEDs17can be efficiently used. Further, it is prevented the holding member20from disturbing light emitted from the LEDs17.

The extending member is the reflection sheet21reflecting from the LED17. With this configuration, by reflecting light by the reflection sheet21, light can be effectively used, which is preferable to improvement of brightness. Since the degree of flexibility in expansion or contraction of the reflection sheet21due to thermal expansion or thermal contraction is improved, unevenness is hard to generate in the light reflected by the reflection sheet21.

The extending member is constituted of the LED substrate18having the LEDs17and the reflection sheet21reflecting light from the LEDs17, and the LED substrate18and the reflection sheet21are sandwiched between the holding member20and the chassis14in the laminated state. With this configuration, the LED substrate18and the reflection sheet21can be held together by the holding member20. In addition, the degree of flexibility in expansion or contraction of both the LED substrate18and the reflection sheet21due to thermal expansion or thermal contraction is improved.

The reflection sheet21is arranged on the LED substrates18on the side opposite to the chassis14, and has the lens insertion holes22band the LED insertion holes23a, into which the LEDs17are inserted, at positions where these holes overlap the LEDs17in a plan view. With this configuration, since light is reflected by the reflection sheet21located on the LED substrate18on the side opposite to the chassis14, light can be used more efficiently, which is suitable for improvement of brightness. Further, since the reflection sheet21includes the lens insertion hole22band the LED insertion hole23a, it is prevented to disturb light emission from the LED17.

The diffuser lenses19diffusing light from the LEDs17are located at such a position as to overlap the LEDs17in a plan view on the LED substrate18on the side opposite to the chassis14. With this configuration, light emitted from the LEDs17can be diffused by the diffuser lenses19and then, emitted. Thereby, unevenness in the emitted light is hard to occur.

The reflection sheet21is constituted of the first reflection sheet22including the lens insertion hole22bthat can pass the diffuser lens19therethrough, and the second reflection sheet23that is interposed between the LED substrate18and the diffuser lens19, is located at such a position as to overlap the lens insertion hole22bprovided in the first reflection sheet22in a plan view (arranged in the lens insertion hole22bin a plan view) and reflects light toward the diffuser lens19. With this configuration, even when the first reflection sheet22is provided with the lens insertion hole22bthat can pass the diffuser lens19therethrough, light can be reflected toward the diffuser lens19by the second reflection sheet23located at such a position as to overlap the lens insertion hole22b(arranged in the lens insertion hole22bin a plan view). As a result, light can be efficiently utilized, which is preferable for improvement of brightness.

The edge of the lens insertion hole22bof the first reflection sheet22and the second reflection sheet23are formed at a position overlapping with each other in a plan view. With this configuration, the edge of the lens insertion hole22bof the first reflection sheet22and the second reflection sheet23are connected to each other in a plan view without any gap. Thus, light can be used more efficiently.

Although the first embodiment of the present invention has been described, the present invention is not limited to this embodiment, and may include, for example, following modification examples. The same members in each of the following modification examples as those in the first embodiment are given the same reference numerals and illustration and description thereof may be omitted.

First Modification Example of First Embodiment

A first modification example of the first embodiment will be described with reference toFIGS. 18 to 20. Here, a contact portion26-1of modified shape is shown.

As shown inFIGS. 18 and 19, the contact portion26-1is annularly formed in such a manner as to surround the central fixed portion25in the body portion24. Describing in detail, the contact portion26-1is annular and extends along the outer edge of the body portion24. In other words, the contact portion26-1is a line forming a circle in a plan view and is shaped like an endless ring. The contact portion26-1has a semicircular cross section and its contact surface with the first reflection sheet22is a spherical surface. When the holding member20in a state shown inFIG. 19is attached to the chassis14, the holding member20is put into a state shown inFIG. 20. At this time, since the annular contact portion26-1entirely surrounds the gap C held between the body portion24and the first reflection sheet22, the gap C is prevented from being opened into the chassis14. Accordingly, light in the chassis14is prevented from leaking to the gap C, thereby preventing light from leaking outside of the chassis14from a small gap held between the fixed portion25and the attachment hole14eon the chassis14through the gap C.

As described above, in this modification example, the fixed portion25is located at the center of the body portion24, while the contact portion26-1is annularly in such a manner as to surround the fixed portion25. With this configuration, by locating the fixed portion25at the center of the body portion24, the holding member20can be stably fixed to the chassis14. In addition, since the annular contact portion26-1surrounding the fixed portion25is in contact with the first reflection sheet22, the reflection sheets22,23and the LED substrate18can be held more suitably in a balanced manner. Moreover, since the gap C held between the body portion24and the first reflection sheet22is surrounded by the annular contact portion26-1, the gap C is prevented from being opened into the chassis14. Accordingly, light in the chassis14can be prevented from leaking to the gap C. Further, for example, when the gap is formed between fixed portion25and the chassis14(attachment hole14e), light in the chassis14can be prevented from leaking outside of the chassis14through the gap C.

The contact portion26-1is linear in a plan view. With this configuration, since the contact portion26-1is in line contact with the first reflection sheet22, the reflection sheets22,23and the LED substrate18can be suitably held while reducing the contact area with the first reflection sheet22.

Second Modification Example of First Embodiment

A second modification example of the first embodiment will be described with reference toFIGS. 21 and 22. Here, a modification of the chassis14-2of is shown.

As shown inFIG. 21, a restricting member28that protrudes toward the front side and can be in contact with the body portion24from the back side is provided at an edge of an attachment hole14e-2on a chassis14-2. The restricting member28is arranged on the entirety of the edge of the attachment hole14e-2and is shaped like a short cylinder as a whole. The outer diameter of the restricting member28is larger than the fixed portion25, and each of the holes18b,22cand23con the reflection sheets22,23and the LED substrate18has such a dimension that allows insertion of the restricting member28. The protruding dimension of the restricting member28from a bottom plate14a-2is larger than a sum of thicknesses of the reflection sheets22,23and the LED substrate18. Accordingly, when the holding member20is attached to the chassis14-2, the body portion24and the contact portion26are supported away from the first reflection sheet22by the restricting member28. That is, positional relationship between the holding member20and the first reflection sheet22in the Z-axis direction is restricted by the restricting member28and the holding member20is kept so as not to be in contact with the first reflection sheet22. With this configuration, the pressing force from the holding member20does not directly act on the reflection sheets22,23and the LED substrate18and thus, the degree of flexibility in expansion or contraction of the reflection sheets22,23and the LED substrate18due to thermal expansion or thermal contraction can be made extremely high.

However, the result of the manufactured holding member20is not necessarily constant, causing some dimensional errors. Depending on the result, even when the restricting member28restricts positional relationship of the holding member20with respect to the first reflection sheet22, the holding member20can contact the first reflection sheet22. Even in such situation, in this embodiment, since the body portion24has the contact portion26, as shown inFIG. 22, only the contact portion26is in contact with the first reflection sheet22, and it is prevented that the body portion24is entirely in contact with the first reflection sheet22. Thereby, the degree of flexibility in expansion or contraction of the reflection sheets22,23and the LED substrate18due to thermal expansion or thermal contraction can be kept high.

As described above, in this modification example, the restricting member28restricting positional relationship of the holding member20with respect to the first reflection sheet22so that the gap C is ensured between the holding member20and the first reflection sheet22is provided. With this configuration, since the restricting member28restricts positional relationship of the holding member20with respect to the first reflection sheet22so that the gap is held between the holding member20and the first reflection sheet22, the reflection sheets22,23and the LED substrate18are easy to expand or contract due to thermal expansion or thermal contraction. However, although the gap cannot be held depending on the result of the manufactured holding member20, even in this case, the contact portion26is in contact with the first reflection sheet22, and therefore, as compared to the case where the entire opposite surface of the holding member to the first reflection sheet22is in contact with the first reflection sheet22, the degree of flexibility in expansion or contraction of the reflection sheets22,23and the LED substrate18can be kept higher.

Third Modification Example of First Embodiment

A third modification example of the first embodiment will be described with reference toFIG. 23. Here, a restricting member28-3modified from the restricting member in the second modification example is shown. Configuration, functions and effects of the restricting member28-3are the same as those in second modification example and thus, overlapping description thereof is omitted.

As shown inFIG. 23, the restricting member28-3is provided integrally with the holding member20. Describing in detail, the restricting member28-3is located adjacent to the fixed portion25of the body portion24in the holding member20. The restricting member28-3is connected to the body portion24and a bottom portion25aof the fixed portion25. The restricting member28-3surrounds the bottom portion25a. When the holding member20is attached to the chassis14, an opposite surface of the restricting member28-3to the chassis14is in contact with the edge of the attachment hole14eon the chassis14, so that the body portion24and the contact portion26are supported at the position away from the first reflection sheet22(non-contact position). As described above, positional relationship between the holding member20and the first reflection sheet22in the Z-axis direction is restricted by the restricting member28-3.

Second Embodiment

A second embodiment of the present invention will be described with reference toFIG. 24orFIG. 25. In the second embodiment, a contact portion126having modified structure is shown. Description of the same configuration, actions and effects as those in the first embodiment is omitted.

As shown inFIGS. 24 and 25, the contact portion126is located adjacent to the fixed portion25of the body portion24. The contact portion126entirely surrounds the bottom portion25aof the fixed portion25and is coupled to the bottom portion25a. That is, in the bottom portion25aof the fixed portion25, a coupling bottom end to the body portion24is partially enlarged in diameter with the contact portion126. Thereby, the fixed portion25is reinforced. The back side surface of the contact portion126is in surface contact with the first reflection sheet22. Although the contact portion126is rectangular in a plan view, its specific shape may be changed as appropriate, for example, to a circle or ellipse. In the reflection sheets22,23and the LED substrate18, the position pressed by the contact portion126from the front side is the almost same as the position pressed by the engaging portion25dfrom the back side in a plan view.

As described above, according to this embodiment, the contact portion126is connected to the fixed portion25. With this configuration, as compared to the case where the contact portion is independent from the fixed portion25, strength of the contact portion126and the fixed portion25can be increased. The contact portion126surrounds the fixed portion25. The intensity of the contact portion126and the fixed portion25can be further increased.

Although the second embodiment of the present invention has been described, the present invention is not limited to this embodiment and for example, may include the following modification examples. In each of the following modification examples, the same members as those in the above-mentioned embodiment are given the same reference numerals and illustration and description thereof may be omitted.

First Modification Example of Second Embodiment

A first modification example of the second embodiment will be described with reference toFIG. 26. Here, contact portion126-1and a first reflection sheet22-1that have modified configuration are shown.

As shown inFIG. 26, the diameter of a communicating hole22c-1on the first reflection sheet22-1is extended in such a manner as to allow even insertion of the contact portion126-1. That is, the communicating hole on the first reflection sheet22-1has a larger diameter than the communicating hole23con the second reflection sheet23and the through hole18bon the LED substrate18. The protruding dimension of the contact portion126-1from the body portion24is larger than that in the second embodiment by the thickness of the first reflection sheet22-1. Accordingly, when the holding member20is attached to the chassis14, the contact portion126-1is in contact with the edge of the communicating hole23con the second reflection sheet23. Thereby, the pressing force from the contact portion26acts on only the second reflection sheet23and the LED substrate18and does not act on the first reflection sheet22-1. Accordingly, the degree of flexibility in expansion or contraction of the first reflection sheet22-1due to thermal expansion or thermal contraction is improved further.

Second Modification Example of Second Embodiment

A second modification example of the second embodiment will be described with reference toFIG. 27. Here, a contact portion126-2and a second reflection sheet23-2that are modified from those in the first modification example are shown.

As shown inFIG. 27, the diameter of a communicating hole23c-2on the second reflection sheet23-2is enlarged in such a manner as to allow even insertion of the contact portion126-2. That is, the diameter of the communicating hole23c-2on the second reflection sheet23-2is equal to that of the communicating hole22c-1on the first reflection sheet22-1and is larger than that of the through hole18bon the LED substrate18. The protruding dimension of the contact portion126-2from the body portion24is larger than that in the first modification example by the thickness of the second reflection sheet23-2. Accordingly, when the holding member20is attached to the chassis14, the contact portion126-2is in contact with the edge of the through hole18bon the LED substrate18. Thereby, the pressing force from the contact portion126-2acts on only the LED substrate18and does not act on the first reflection sheet22-1and the second reflection sheet23-2. Accordingly, the degree of flexibility in expansion or contraction of the first reflection sheet22-1and the second reflection sheet23-2due to thermal expansion or thermal contraction is enhanced further.

Third Embodiment

A third embodiment of the present invention will be described below with reference toFIGS. 28 to 30. In the third embodiment, a holding member220is modified in shape from that in the second embodiment. Overlapping description of the same configuration, actions and effects as those in the first and second embodiments is omitted.

The holding member220, as shown inFIG. 28, is configured of two components: a first component29including a body portion224and a fixed portion225and a second component30attachably and detachably assembled to the first component29from the front side. The first component29is provided with an attaching opening29afor attaching the second component30, which is opened on the front side. The attaching opening29apasses through the body portion224of the first component29, and has a depth over the entire length of a bottom portion225aof the fixed portion225. Accordingly, the attaching opening29ais connected to a grooved portion225cformed on the fixed portion225. That is, the attaching opening29ais also opened to the back side through the grooved portion225c. The attaching opening29ahas a circular cross section. An inclined surface29bfacing the attaching opening29ais provided on an inner surface of each elastic engaged portion225bforming the fixed portion225. The inclined surface29bis arranged at a protruding bottom end of the elastic engaged portion225b. The inclined surface29bis gradually inclined inward from the protruding bottom end of the elastic engaged portion225btoward the protruding front end, so that the protruding bottom end of the elastic engaged portion225bbecomes narrower toward the protruding front end side and becomes wider toward the protruding front end side. The diameter of a fixed portion225is substantially constant over the entire length, and is slightly smaller than each of the holes14e,18b,22cand23con the reflection sheets22,23, LED substrate18and the chassis14. Each elastic engaged portion225bis not provided with the engaging portion25das shown in the first embodiment.

The second component30has a substantially T-shaped cross section, and includes a bottom portion30aextending in parallel to the body portion224of the first component29and a shaft portion30bprotruding from the bottom portion30atoward the back side. The bottom portion30ais substantially circular in a plan view, and has the almost same dimension of the body portion224of the first component29. The shaft portion30bis shaped like a cylinder having a substantially constant diameter over the entire length, and has the protruding dimension from the bottom portion30a, which is the almost same as the dimension of the first component29in the Z-axis direction. The shaft portion30bhas the diameter that is slightly smaller than the attaching opening29aof the first component29and thus, can be inserted into or pulled out of the attaching opening29a.

Subsequently, the operation of attaching the holding member220with the above-mentioned configuration to the chassis14will be described. First, as shown inFIG. 29, first, the first component29is attached to the chassis14. At this time, the fixed portion225of the first component29is inserted into each of the holes14e,18b,22cand23con the reflection sheets22,23, the LED substrate18and the chassis14, respectively. In this state, the fixed portion225is not engaged with the chassis14. Next, the second component30is attached to the first component29from the front side. When the shaft portion30bof the second component30is inserted into the attaching opening29aof the first component29from the front side and reaches a predetermined depth, a front end of the shaft portion30bcontacts the inclined surface29bof each elastic engaged portion225b. When the second component30is further inserted in this state, as shown inFIG. 30, the inclined surface29bis pressed by the front end of the shaft portion30b, and each elastic engaged portion225bis elastically deformed along the inclination so as to extend outward. That is, each elastic engaged portion225bis extended by the shaft portion30bto be elastically deformed and is engaged with the edge of the attachment hole14e. Each elastic engaged portion225bis restricted from being elastically returned inward (deformed to be closed) by the shaft portion30barranged inside of the elastic engaged portion225b. This can prevent the phenomenon that the holding member220is carelessly detached from the chassis14. When each elastic engaged portion225bis pressed by the shaft portion30b, each elastic engaged portion225bmay be subjected to plastic deformation.

As described above, in this embodiment, the holding member220includes the body portion224that sandwiches the reflection sheets22,23and the LED substrate18between the body portion224and the chassis14and the fixed portion225that protrudes from the body portion224toward the chassis14and is fixed to the chassis14, the fixed portion225has the elastic engaged portion225bthat is elastically deformable and is engaged on the side opposite to the reflection sheets22,23and the LED substrate18through the chassis14, and the holding member220is constituted of the first component29having the body portion224and the fixed portion225and the second component30that is attached to the first component29and restricts elastic deformation of the elastic engaged portion225b. With this configuration, when the second component30is attached to the first component29in the state where the first component29is attached to the chassis14, elastic deformation of the elastic engaged portion225bthat is engaged on the side opposite to the reflection sheets22,23and the LED substrate18through the chassis14is restricted. Thereby, the holding member220can be strongly prevented from being detached from the chassis14.

Fourth Embodiment

A fourth embodiment of the present invention will be described with reference toFIG. 31orFIG. 32. In the fourth embodiment, the second reflection sheet23in the first embodiment is omitted. Overlapping description of the same configuration, actions and effects as those in the first embodiment is omitted.

In this embodiment, the second reflection sheet23according to the first embodiment is omitted, and as shown inFIG. 31, a reflecting layer318din place of the second reflection sheet23is formed on the front side surface of an LED substrate318. The reflecting layer318dassumes a white color having excellent light reflectivity, and is formed, for example, by printing paste containing a metal oxide on the surface of the LED substrate318. Screen printing and ink jet printing are preferable as printing means. Although the reflecting layer318dcan be formed on the almost all of the front side surface of the LED substrate318, the reflecting layer318dmay be formed on a part opposite to the diffuser lenses19on the LED substrate318. The reflecting layer318dcan reflect light returned from the diffuser lenses19toward the diffuser lenses19again. As shown inFIG. 32, only the first reflection sheet22is sandwiched between the body portion24of the holding member20and the LED substrate318.

Fifth Embodiment

A fifth embodiment of the present invention will be described below with reference toFIG. 33. In the fifth embodiment, the diffuser lenses19and the second reflection sheet23in the first embodiment are omitted. Overlapping description of the same configuration, actions and effects as those in the first embodiment is omitted.

In this embodiment, since the diffuser lenses19and the second reflection sheet23in the first embodiment are omitted, light emitted from each of the LEDs17, as shown inFIG. 33, directly reaches the optical member15. A first reflection sheet422is provided with an opened LED insertion hole422ethat can pass each of the LEDs17therethrough (is smaller than the lens insertion hole22bin the first embodiment) and can be placed directly on the LED substrate18. In adopting this embodiment, since the region between the LEDs17is easy to be visually recognized as a dark place, in order to prevent uneven brightness, it is preferred that the alignment pitch of the LEDs17in the X-axis direction and the Y-axis direction is smaller than that in the first embodiment.

Other Embodiment

The present invention is not limited to the embodiments described in the above description and figures, and for example, following embodiments fall within the technical scope of the present invention.

(1) Also in embodiments other than each of the above-mentioned embodiments, specific shape of the contact portion can be changed as appropriate. For example, a cylindrical, prismatic, conical or pyramid contact portion, or a contact portion having an angular (triangular) and elliptic cross section also falls within the scope of the present invention. When the contact portion is cylindrical or prismatic, the contact portion is in surface contact with the extending member (each reflection sheet or the LED substrate), and when the contact portion is conical or pyramid, the top of the contact portion is in point contact with the extending member. Further, for example, the contact portion shaped like a straight line having a predetermined length in a plan view, an elliptic endless ring, a rectangular endless ring or a ring having an end (C-like) in a plan view also falls within the scope of the present invention.

(2) Although the contact portions located away from the fixed portion are provided at the outer edge of the body portion in the first embodiment (including each of the modification examples) and the third to fifth embodiments, the contact portions can be arranged at positions other than the outer edge of the body portion, specifically, between the outer edge of the body portion and the fixed portion. In this case, the contact portions can be arranged at both the outer edge of the body portion and the other position.

(3) Although the plurality of point contact portions are located at the body portion to be symmetrical in a plan view in the first embodiment, as a matter of course, the plurality of contact portions may be located at asymmetrical positions of the body portion.

(4) Although the four point contact portions in a plan view are provided at the body portion in the first embodiment, as a matter of course, the number of contact portions may be three or smaller or five or larger.

(5) Although the part of the body portion between the fixed portion and the contact portion has elasticity in the first embodiment (including each of the modification examples) and the third to fifth embodiments, the body portion does not necessarily have elasticity and the body portion that is hardly elastically deformed or is not elastically deformed at all also falls within the present invention. Even in this case, since positions where the pressing forces are applied from the front side and the back side from the extending member (each reflection sheet or the LED substrate) are shifted from each other in a plan view, concentration of stress on the extending member can be preferably mitigated and the effect of improving the degree of flexibility in expansion or contraction can be obtained.

(6) Contrary to (5) above, in order to impart elasticity to the part of the body portion between the fixed portion and the contact portion, for example, it may be configured such that flexure is facilitated and that, by increasing the protruding dimension of the contact portion from the body portion, the body portion can be elastically deformed even when no dimensional error occurs.

(7) Although the fixed portion is located at such a position as to be concentric with the body portion in each of the above-mentioned embodiments, the fixed portion located at such a position as to be eccentric with the body portion also falls within the present invention. For example, the fixed portion can be located at the outer edge of the body portion. In this case, in locating the contact portion at the outer edge of the body portion, it is preferred that the contact portion is located on a straight line connecting the center of the fixed portion to the center of the body portion, thereby ensuring the maximum distance between the contact portion and the fixed portion.

(8) Although the contact portion connected to the fixed portion surrounds the fixed portion in the second embodiment (including each of the modification examples), the contact portion connected to the fixed portion, which does not surround the fixed portion, that is, the contact portion connected to only a part of the bottom portion also falls within the present invention.

(9) As a matter of course, the configuration shown in the second and third modification examples of the first embodiment can be applied to the configuration described in the second to fifth embodiments.

(10) As in the same manner as (9) above, as a matter of course, the configuration shown in the first and second modification example of the second embodiment can be applied to the first embodiment. In such case, a hole that passes the contact portion therethrough, separately from a communicating hole that passes the fixed portion therethrough, may be formed on the first reflection sheet or the second reflection sheet.

(11) Also in embodiments other than each of the above-mentioned embodiments, the shape of the body portion of the holding member can be changed as appropriate. Specifically, the body portion shaped to be elliptic or quadrate (rectangular or square) in a plan view also falls within the scope of the present invention.

(12) Although the holding member is arranged between the adjacent LEDs on the LED substrate in each of the above-mentioned embodiments, the holding member located in a region overlapping the LED on the LED substrate in a plan view falls within the scope of the present invention. In this case, it is preferable to provide an insertion hole on the overlapping position of the holding member with the LED.

(13) Also in embodiments other than each of the above-mentioned embodiments, attachment position and the number of attached holding members with respect to each LED substrate can be changed as appropriate. Similarly, attachment position and the number of attached holding members with respect to chassis can be changed as appropriate.

(14) Although the plug-in type fixed portion is adopted as the attachment structure of the holding member to the chassis in each of the above-mentioned embodiments, slide-type may be adopted as the attachment structure. In an example of the slide-type attachment structure, by adopting a hook-type fixed portion, pushing the body portion toward the bottom plate of the chassis and then, sliding the body portion along the bottomplate, the hooked part of the fixed portion is engaged with the edge of the attachment hole.

(15) Although the fixed portion of the holding member is engaged passing through the chassis in each of the above-mentioned embodiments, the specific fixing method of the fixed portion to the chassis can be changed as appropriate. For example, configuration in which the attachment hole and the elastic engaged portion are omitted and a bottom part passing through the through hole of the LED substrate is fixedly attached to the inner wall surface of the chassis with the adhesive or the like falls within the scope of the present invention. In this case, means such as deposition and welding other than the adhesive can be adopted.

(16) Although the supporting portion and the body portion are located in the complex function-type holding member so as to be concentric with each other in each of the above-mentioned embodiments, the supporting portion located eccentric with the body portion also falls within the scope of the present invention. Further, arrangement in which the supporting portion and the fixed portion do not overlap each other in a plan view also falls within the scope of the present invention.

(17) Although the supporting portion of the complex function-type holding member is shaped like a tapered cone in each of the above-mentioned embodiments, for example, the supporting portion shaped like a tapered pyramid falls within the scope of the present invention. Further, the supporting portion is not necessarily tapered and the supporting portion shaped like a cylinder or prismatic column having a constant diameter also falls within the scope of the present invention.

(18) Although the supporting portion of the complex function-type holding member is in contact with the diffuser plate extending straight in the X-axis direction and the Y-axis direction in each of the above-mentioned embodiments, the supporting portion that is not in contact with the straight diffuser plate (specifically, the protruding front end of the supporting portion is located closer to the LED than the surface of the diffuser plate on the LED side) falls within the scope of the present invention. With such configuration, for example, even when the diffuser plate thermally expands due to change in the thermal environment in the backlight unit, the diffuser plate is allowed to be deformed so as to warp toward the LED in a clearance held between the diffuser plate and the supporting portion. Thereby, wrinkle or flexure is hard to occur in the diffuser plate and thus, uneven brightness is also hard to occur in illumination light emitted from the diffuser plate.

(19) Although the supporting portion of the complex function-type holding member is point in the plane of the optical member in each of the above-mentioned embodiments, a linear or sheet-like supporting portion in the plane of the optical member also falls within the scope of the present invention.

(20) Although the single function-type holding member and the complex function-type holding member are concurrently used in each of the above-mentioned embodiments, configuration using only the single function-type holding member and configuration using only the complex function-type holding member falls within the scope of the present invention. Further, in concurrently using the single function-type holding member and the complex function-type holding member, the ratio of these members can be changed as appropriate.

(21) Although the color of the surface of the holding member is white in each of the above-mentioned embodiments, the color of the surface of the holding member may be, for example, creamy white or silver. Further, the color of the surface can be set by coating the surface of the holding member with a paint of desired color.

(22) Although the reflection sheets are provided as the “extending members” in each of the above-mentioned embodiments, the configuration having no reflection sheet also falls within the present invention.

(23) Although the LED substrate is provided as the “extending member” in each of the above-mentioned embodiments, configuration having no LED substrate also falls within the present invention. In this case, a discharge lamp such as a cold cathode tube (linear light source) or a sheet-like light source such as an organic EL may be used as the light source.

(24) Although the reflection sheet and the LED substrate are used as the “extending member” in each of the above-mentioned embodiments, for example, when a sheet-like heat radiating member is interposed between the LED substrate and the chassis, the heat radiating member may be used as the “extending member”.

(25) Although the five-mounted type, the six-mounted type and the eight-mounted type of LED substrates are combined as appropriate in each of the above-mentioned embodiments, an LED substrate that mounts the number of LEDs other than five, six and eight LEDs falls within the scope of the present invention.

(26) Although the LED that includes the LED chip emitting only blue light and emits white light by means of the phosphor is used in each of the above-mentioned embodiments, an LED that includes the LED chip emitting only ultraviolet light and emits white light by means of the phosphor falls within the scope of the present invention.

(27) Although the LED that includes the LED chip emitting only blue light and emits white light by means of the phosphor is used in each of the above-mentioned embodiments, an LED that has three types of LED chips emitting R, G, B, respectively, falls within the scope of the present invention. Moreover, an LED that has three types of LED chips emitting C (cyan), M (magenta), Y (yellow), respectively, also falls within the scope of the present invention.

(28) Although the LED that emits white light in each of the above-mentioned embodiments, an LED that emits red light, an LED that emits blue light and an LED that emits green light may be combined as appropriate.

(29) Although the LED is used as the light source in each of the above-mentioned embodiments, a point light source other than the LED also falls within the scope of the present invention.

(30) Although the diffuser lens diffusing light from the LED is used in the first to fourth embodiments, an optical lens other than the diffuser lens (for example, a collective lens) falls within the scope of the present invention.

(31) Also in embodiments other than each of the above-mentioned embodiments, screen size and aspect ratio of the liquid crystal display device can be changed as appropriate.

(32) Although the liquid crystal panel and the chassis are arranged in the longitudinally mounted state so that the short-side direction matches the vertical direction in each of the above-mentioned embodiments, configuration in which the liquid crystal panel and the chassis are arranged in the longitudinally mounted state so that the long-side direction matches the vertical direction also falls within the scope of the present invention.

(33) Although the TFT is used as the switching component of the liquid crystal display device in each of the above-mentioned embodiments, the present invention can also be applied to a liquid crystal display device using a switching component (for example, a thin film diode (TFD)) other than TFT and the monochrome liquid crystal display device other than the color liquid crystal display device.

(34) Although the liquid crystal display device using the liquid crystal panel as the display panel is illustrated in each of the above-mentioned embodiments, the present invention can be applied to a display device using the other type of display panel.

(35) Although the television receiver provided with a tuner is illustrated in each of the above-mentioned embodiments, the present invention can be applied to a display device having no tuner.

(36) Although the two types of holding members are distinguished as the “single function-type” and the “complex function-type” in each of the above-mentioned embodiments, the “single function-type” does not mean that the holding member has no function other than the function of holding the extending member. The terms “single function-type” and “complex function-type” are made on the basis of presence or absence of the function of supporting the optical member for convenience of explanation, and the “single function-type” holding member can have any function accompanying the above-mentioned holding function (e.g. a function of positioning with respect to the extending member) and other additional functions.