JP6689727B2 - Backlight device and display device including the same - Google Patents

Description

  Embodiments of the present invention relate to a backlight device and a display device including the backlight device.

In recent years, liquid crystal display devices have been widely used as display devices for smartphones, personal assistant devices (PADs), tablet computers, car navigation systems, and the like. In general, a liquid crystal display device includes a liquid crystal display panel and a planar illumination device (backlight device) that is disposed so as to overlap the back surface of the liquid crystal display panel and illuminates the liquid crystal display panel. A conventional backlight device has a reflective layer, a light guide plate (light guide), an optical sheet, an LED as a light source, and a resin-made rectangular frame-shaped frame. The reflective layer, the light guide plate, and the optical sheet are laminated and arranged on top of each other and arranged in the frame. As a result, the reflective layer, the light guide plate, and the optical sheet are held and positioned by the frame.
Further, there has been proposed a configuration in which a frame is fitted in a housing (backlight cover) made of a metal plate, and a reflective layer, a light guide plate, and an optical sheet are arranged in the hollow portion of the frame.

JP, 2010-26216, A Japanese Patent No. 5122657 JP, 10-170919, A

2. Description of the Related Art In recent years, liquid crystal display devices have been required to have a further narrower frame and thinner thickness as the display area becomes larger. However, the dimensions such as the width and the thickness of the frame of the above-described backlight device are approaching the limit dimensions that can be formed by injection molding, and it is difficult to meet such a request.
Further, as the frame becomes narrower, the tolerance between the effective illumination area of the backlight device and the effective area of the liquid crystal display becomes smaller. Therefore, when the backlight device is attached to the liquid crystal display device, the liquid crystal display effective area may be shifted out of the effective illumination area, and as a result, the display quality may be degraded.
An object of the embodiment described here is to provide a backlight device capable of further thinning and narrowing a frame while avoiding such a deterioration in display quality, and a display device including the same.

  The backlight device according to the embodiment includes a frame-shaped frame formed of a transparent resin, a first diffusion adhesive layer provided on the first surface of the frame and having a light diffusion property, and the first frame of the frame. A second diffusion adhesive layer provided on the second surface opposite to the surface and having a light diffusing property, a reflection sheet attached to the frame via the first diffusion adhesive layer, and the reflection sheet in the frame The light guide plate mounted on the top and the light source which is arrange | positioned in the said frame and injects light into the said light guide plate are provided.

FIG. 1 is a perspective view showing a display surface side of a liquid crystal display device according to an embodiment. FIG. 2 is a perspective view showing the back side of the liquid crystal display device. FIG. 3 is an exploded perspective view of the liquid crystal display device. FIG. 4 is a cross-sectional view of the liquid crystal display device taken along line AA of FIG. 1. FIG. 5 is a cross-sectional view of the liquid crystal display device taken along line BB of FIG. 1. FIG. 6A is a diagram schematically showing the distribution of diffusivity of the diffusive pressure-sensitive adhesive layer provided on the frame. FIG. 6B is a diagram schematically showing the distribution of diffusivity of the diffusive pressure-sensitive adhesive layer provided on the frame. FIG. 7 is a diagram schematically showing an example of a manufacturing apparatus of a backlight device. FIG. 8: is a perspective view which shows the sheet base material in the manufacturing process of a backlight device. FIG. 9 is a perspective view showing a state in which diffusion adhesive layers are respectively formed on the first surface and the second surface of the sheet base material in the manufacturing process. FIG. 10 is a perspective view showing a state where the inner window (inner hole) of the frame is punched out in the manufacturing process. FIG. 11: is a perspective view which shows the state which attached the reflection sheet to one diffusion adhesive layer in the said manufacturing process. FIG. 12 is a perspective view showing a backlight device having an outer shape formed by punching in the manufacturing process. FIG. 13 is a cross-sectional view of the liquid crystal display device according to the second embodiment. FIG. 14 is a vertical cross-sectional view of the liquid crystal display device according to the second embodiment. FIG. 15 is a cross-sectional view of the liquid crystal display device according to the third embodiment. FIG. 16 is a vertical cross-sectional view of the liquid crystal display device according to the third embodiment. FIG. 17 is a cross-sectional view of the liquid crystal display device according to the fourth embodiment. FIG. 18 is a vertical cross-sectional view of the liquid crystal display device according to the fourth embodiment. FIG. 19 is a perspective view showing the display surface side of the liquid crystal display device according to the fifth embodiment. 20 is a cross-sectional view of the liquid crystal display device taken along the line CC of FIG. FIG. 21 is a sectional view of a liquid crystal display device according to a first modification. FIG. 22 is a cross-sectional view of a liquid crystal display device according to the second modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
It should be noted that the disclosure is merely an example, and those skilled in the art can appropriately modify the invention while keeping the gist of the invention and easily conceived of the invention are naturally included in the scope of the invention. Further, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part as compared with the actual mode, but this is merely an example, and the interpretation of the present invention will be understood. It is not limited. In the specification and the drawings, the same elements as those described above with reference to the drawings already described are denoted by the same reference numerals, and detailed description thereof may be appropriately omitted.

(First embodiment)
1 and 2 are perspective views respectively showing a display surface side and a back surface side of the liquid crystal display device according to the first embodiment, and FIG. 3 is an exploded perspective view of the liquid crystal display device.
The liquid crystal display device 10 can be used by incorporating it into various electronic devices such as a smartphone, a tablet terminal, a mobile phone, a notebook type PC, a portable game machine, an electronic dictionary, a television device, and a car navigation system.

  As shown in FIG. 1 to FIG. 3, the liquid crystal display device 10 is arranged so as to overlap an active matrix type liquid crystal display panel 12 and a display surface 12 a which is one flat surface of the liquid crystal display panel 12. A cover panel 14 that covers the entire display surface and a backlight unit (backlight device) 20 that is arranged to face the back surface, which is the other flat plate surface of the liquid crystal display panel 12, are provided.

  4 is a cross-sectional view of the liquid crystal display device taken along line AA of FIG. 1, and FIG. 5 is a cross-sectional view of the liquid crystal display device taken along line BB of FIG. As shown in FIGS. 3 to 5, the liquid crystal display panel 12 includes a first substrate SUB1 having a rectangular flat plate shape, a second substrate SUB2 having a rectangular flat plate shape facing the first substrate SUB1, and a first substrate SUB1. The liquid crystal layer LQ provided between the second substrate SUB2 and the second substrate SUB2. The peripheral portion of the second substrate SUB2 is attached to the first substrate SUB1 with the sealing material SE. The polarizing plate PL1 is attached to the surface of the second substrate SUB2 to form the display surface 12a of the liquid crystal display panel 12. A polarizing plate PL2 is attached to the surface of the first substrate SUB1 (back surface of the liquid crystal display panel 12). The polarizing plate PL2 has a dimension slightly larger than the outer dimension of the first substrate SUB1 in a plan view (a state in which the liquid crystal display panel is viewed from the normal direction of the surface of the liquid crystal display panel. The same applies hereinafter). And covers the entire surface of the first substrate SUB1.

  In the liquid crystal display panel 12, a rectangular display area (active area) DA is provided in an area inside the sealing material SE in a state where the display surface 12a is viewed in a plan view, and an image is displayed in the display area. Further, a rectangular frame-shaped frame area (non-display area) ED is provided around the display area DA. The liquid crystal display panel 12 is a transmissive type having a transmissive display function of displaying an image by selectively transmitting light from the backlight unit 20 to the display area DA. The liquid crystal display panel 12 may have a configuration corresponding to a lateral electric field mode in which an electric field substantially parallel to the main surface of the substrate is mainly used as a display mode, or an electric field substantially perpendicular to the main surface of the substrate is mainly used. You may have the structure corresponding to a longitudinal electric field mode.

  In the illustrated example, the flexible printed circuit board (FPC) 22 is joined to the end portion on the short side of the first substrate SUB1 and extends outward from the liquid crystal display panel 12. A semiconductor element such as the drive IC chip 21 is mounted on the FPC 22 as a signal supply source that supplies a signal necessary for driving the liquid crystal display panel 12.

  As shown in FIGS. 1 to 5, the cover panel 14 is formed in a rectangular flat plate shape by a glass plate or an acrylic transparent resin, for example. The cover panel 14 has a width and a length that are larger than the dimensions (width and length) of the liquid crystal display panel 12. As a result, the cover panel 14 has a larger area than the liquid crystal display panel 12 in a plan view. A frame-shaped light-shielding layer RS is formed on the peripheral portion of the back surface of the cover panel 14 (the surface on the liquid crystal display panel 12 side or the surface opposite to the surface facing the viewer). Areas of the cover panel 14 other than the area facing the display area DA are shielded by the light shielding layer RS. The light shielding layer RS may be formed on the upper surface (display surface) of the cover panel 14.

The back surface (back surface) of the cover panel 14 is attached to the polarizing plate PL1 of the liquid crystal display panel 12 with a light-transmitting or transparent adhesive or pressure-sensitive adhesive, for example, a pressure-sensitive adhesive sheet AD made of an optical transparent resin. ing. As a result, the cover panel 14 covers the entire display surface 12a of the liquid crystal display panel 12. The adhesive sheet AD is formed in the same size as the polarizing plate PL1 and is aligned and attached to the polarizing plate PL1. Note that, instead of the adhesive sheet AD, it is also possible to adopt a configuration in which an adhesive is applied to the polarizing plate PL1 and its periphery.
The peripheral edge of the cover panel 14 projects outward from the outer peripheral edge of the liquid crystal display panel 12. The long sides of the cover panel 14 and the long sides of the liquid crystal display panel 12 are in a substantially parallel state with a predetermined gap. The short sides of the cover panel 14 and the short sides of the liquid crystal display panel 12 are substantially parallel to each other with a predetermined gap. In the present embodiment, the distance between the long side of the cover panel 14 and the long side of the liquid crystal display panel 12, that is, the width of the long side peripheral portion of the cover panel 14 is the short side of the cover panel 14 and the liquid crystal display panel 12. It is formed to be smaller than the distance to the short side, that is, the width of the short side peripheral portion of the cover panel.

  As shown in FIGS. 3 to 5, the backlight unit 20 includes a rectangular frame-shaped frame 16 attached to the back surface of the liquid crystal display panel 12, a reflection sheet RE attached to the back surface of the frame 16, and a frame 16. A plurality of optical members arranged inside and a light source unit 30 for supplying light incident on the optical members are provided.

  The frame 16 having a frame shape is made of a sheet material having a thickness T1 of 0.40 mm (400 μm) or less, for example, 0.10 to 0.25 mm (100 to 255 μm). The frame 16 has outer dimensions (width, length) slightly larger than the outer shape of the liquid crystal display panel 12 and smaller than the outer shape of the cover panel 14. As the sheet material, a light-transmissive or transparent resin sheet, for example, a polyethylene terephthalate (PET) sheet can be used. The resin sheet material used here includes a sheet having a thickness of about 100 to 300 μm, a film having a thickness smaller than 100 μm, a thin film, and the like.

As will be described later, the frame 16 is formed by punching a resin sheet material and has a predetermined dimension. Further, the frame 16 is formed to have a uniform thickness T1 over the entire circumference, and there is no unevenness in the thickness direction (Z direction when viewed in cross section). In the present embodiment, the thickness T1 (thickness of the sheet material) of the frame 16 is 0.188 mm (188 μm) or 0.25 mm (250 μm). The frame 16 has a second surface (upper surface) SF2 on the liquid crystal display panel 12 side and a first surface (lower surface) SF1 on the side opposite to the second surface SF2.
The frame 16 has a pair of long side portions 16a and 16b facing each other and a pair of short side portions 16c and 16d facing each other. The width W1 of each long side portion 16a, 16b is formed to be 0.6 mm (600 μm) or less, for example, 0.4 to 0.5 mm (400 to 500 μm). The width W2 of the one short side portion 16c is equal to or less than 0.6 mm (600 μm), for example, 0.4 to 0.5 mm (400 to 500 μm), like the width W1. Further, W3 of the other short side portion 16d is formed to be equal to or less than 0.6 mm (600 μm) like the width W2, for example, 0.4 to 0.5 mm (400 to 500 μm). The width W3 of the short side portion 16d may be formed wider than W2. Further, a plurality of recesses 17 are provided on the inner edge side of the other short side portion 16d.

The first diffusion adhesive layer 24a is formed on the lower surface (first surface) SF1 of the frame 16. Further, the second diffusion adhesive layer 24b is formed on the upper surface (second surface) SF2 of the frame 16. As shown in FIG. 4, the first diffusing adhesive layer 24a and the second diffusing adhesive layer 24b each have a light diffusive property in which a large number of minute beads B having a refractive index different from that of the transparent adhesive are mixed. It is made of adhesive. As the adhesive, for example, an acrylic adhesive, an epoxy adhesive, a UV curing adhesive, etc. can be used. As the fine beads B, light-transmissive hollow silica particles, glass particles, or synthetic resin particles can be used. The diffusivity of the diffusion adhesive layer can be appropriately adjusted by adjusting the content of the micro beads B, the refractive index of the micro beads B, and the like. In the present embodiment, the diffusivity da of the first diffusion adhesive layer 24a is larger than the diffusivity db of the second diffusion adhesive layer 24b. Here, db is the diffusivity of the second diffusion adhesive layer 24b in the long side portions 16a, 16b and the short side portion 16c, and it does not matter how many layers the second diffusion adhesive layer 24b in the portion is composed of.
The thickness T2 of the first diffusion adhesive layer 24a is, for example, 0.01 to 0.06 mm (10 to 60 μm), and the thickness of the second diffusion adhesive layer 24b in the long side portions 16a, 16b and the short side portion 16c. The thickness T3 is formed to be 0.01 to 0.06 mm (10 to 60 μm). Accordingly, the total thickness of the frame 16, the first diffusion adhesive layer 24a, and the second diffusion adhesive layer 24b is, for example, 0.32 to 0 on the long side portions 16a and 16b and the short side portion 16c side, which are the maximum thickness. It is formed to 0.52 mm (320 to 520 μm).

  In at least the long side portions 16a and 16b of the frame 16, the first diffusion adhesive layer 24a has the same width as the width W1 of the long side portions 16a and 16b, and at least the outer surface (outer edge) of the frame 16 and the first side. The outer surface (outer edge) of the diffusion adhesive layer 24a is flush. In the present embodiment, the inner side surface (inner edge) side of the first diffusion adhesive layer 24a is also flush with the inner side surface (inner edge) of the frame 16. Alternatively, when viewed at intervals between the long side portions 16a and 16b of the frame 16, the inner dimension between the long side portions 16a and 16b and the first diffusion adhesive layer 24a provided on the long side portion 16a and the long side portion 16b are The inner dimension with the provided first diffusion adhesive layer 24a is equal. Similarly, the outer dimension of the long side portions 16a and 16b is equal to the outer dimension of the first diffusion adhesive layer 24a provided on the long side portion 16a and the first diffusion adhesive layer 24a provided on the long side portion 16b. .

In the present embodiment, also in the short side portions 16c and 16d of the frame 16, the first diffusion adhesive layer 24a has the same width as the widths W2 and W3 of the short side portions 16c and 16d, and the outer surface of the frame 16 and The inner side surface is flush with the outer side surface and the inner side surface of the first diffusion adhesive layer 24a. Alternatively, when viewed at intervals of the short side portions 16c and 16d of the frame 16, the inner dimension between the short side portions 16c and 16d and the first diffusion adhesive layer 24a and the short side portion 16d provided on the short side portion 16c are The inner dimension with the provided first diffusion adhesive layer 24a is equal. Similarly, the outer dimensions of the short side portions 16c and 16d and the outer dimensions of the first diffusion adhesive layer 24a provided on the short side portion 16c and the first diffusion adhesive layer 24a provided on the short side portion 16d are equal.
In the present embodiment, a double-sided tape having an adhesive layer on both surfaces of a translucent substrate is used as the first diffusion adhesive layer 24a and the second diffusion adhesive layer 24b. The thickness of each pressure-sensitive adhesive layer can be easily adjusted by changing the thickness of each base material.

  At least in the long side portions 16a and 16b of the frame 16, the second diffusion adhesive layer 24b has the same width as the width W1 of the long side portions 16a and 16b, and at least the outer surface (outer edge) of the frame 16 and the second side. The outer surface (outer edge) of the diffusion adhesive layer 24b is flush. In the present embodiment, the inner side surface (inner edge) side of the second diffusion adhesive layer 24b is also flush with the inner side surface (inner edge) of the frame 16. Alternatively, when viewed at intervals between the long side portions 16a and 16b of the frame 16, the inner dimension between the long side portions 16a and 16b and the second diffusion adhesive layer 24b and the long side portion 16b provided on the long side portion 16a are The inner dimension with the provided second diffusion adhesive layer 24b is equal. Similarly, the outer dimension of the long side portions 16a and 16b is equal to the outer dimension of the second diffusion adhesive layer 24b provided on the long side portion 16a and the second diffusion adhesive layer 24b provided on the long side portion 16b. .

  In the present embodiment, also in the short side portions 16c and 16d of the frame 16, the second diffusion adhesive layer 24b has the same width as the widths W2 and W3 of the short side portions 16c and 16d. The inner side surface is flush with the outer side surface and the inner side surface of the second diffusion adhesive layer 24a. Alternatively, when viewed at intervals of the short side portions 16c and 16d of the frame 16, the inner dimension between the short side portions 16c and 16d and the second diffusion adhesive layer 24b and the short side portion 16d provided on the short side portion 16c are different. The inner dimension with the provided second diffusion adhesive layer 24b is equal. Similarly, the outer dimensions of the short side portions 16c and 16d and the outer dimensions of the second diffusion adhesive layer 24b provided on the short side portion 16c and the second diffusion adhesive layer 24b provided on the short side portion 16d are the same. equal.

  The second diffusion adhesive layer 24b on the short side portion 16c and each of the long side portions 16a and 16b of the frame 16 is formed thicker than the second diffusion adhesive layer 24b on the short side portion 16d. Is formed to a thickness of. In this case, the second diffusion adhesive layer 24b in the long side portions 16a and 16b and the short side portion 16c is formed by laminating two adhesive layers having the same thickness as the second diffusion adhesive layer 24b in the short side portion 16d. can do. Further, by making the second diffusion adhesive layer 24b on the short side portion 16d on the light source side thinner than the second diffusion adhesive layer 24b on the long side portions 16a and 16b, the printed circuit board 32 of the light source unit 30 to be described later is provided. A gap is formed for passing.

Further, as schematically shown in FIG. 6A, in the first diffusion adhesive layer 24a, a portion provided on the short side portion 16c of the frame 16, that is, the short side portion 16c located on the opposite side of the light source unit 30. The content of the microbeads B may be adjusted so that the diffusivity of is smaller than the diffusivity of the portions provided on the long side portions 16a and 16b. Similarly, in the second diffusion adhesive layer 24b, the diffusivity of the portion provided on the short side portion 16c of the frame 16 is lower than the diffusivity of the portion provided on each of the long side portions 16a and 16b. The content of the micro beads B may be adjusted so that
Alternatively, as schematically shown in FIG. 6B, the diffusivity of the first diffusion adhesive layer 24a provided on each of the long side portions 16a and 16b gradually increases from the light source unit 30 side toward the short side portion 16c. The content of the microbeads B may be adjusted so as to be high. Similarly, the inclusion of microbeads such that the diffusivity of the second diffusion adhesive layer 24b provided on each of the long side portions 16a and 16b gradually increases from the light source unit 30 side toward the short side portion 16c. The amount may be adjusted.

6A and the configuration shown in FIG. 6B are combined, that is, the diffusivity of the first diffusion adhesive layer 24a and the second diffusion adhesive layer 24b of the short side portion 16c is set to the long side portions 16a and 16b. It may be adjusted to be less diffusive at any location. For example, a configuration is adopted in which the diffusivity of the short side portions 16c is lower than the diffusivity of the long side portions 16a and 16b at the position closest to the light source. Alternatively, a configuration is adopted in which the diffusivity of the short side portions 16c is lower than the diffusibility of the long side portions 16a and 16b at the position farthest from the light source. Furthermore, a configuration is adopted in which the long side portions 16a and 16b have the same diffusibility in the central portion in the length direction and the short side portion 16c.
In FIGS. 6A and 6B, the difference in the diffusivity in each diffusion adhesive layer is shown by the number of the micro beads B. However, the particle size and the particle size distribution of the micro beads B may be changed to make the diffusivity different. Means for changing the diffusivity, such as employing materials having different refractive indexes and transmittances, are appropriately adopted.
It is also possible to adjust the translucency of the frame 16 by performing white dot printing or the like on the back surface of the frame 16 facing the reflection sheet RE. In this case, the density of the dots of the white dot printing is gradually changed from the one close to the light source unit 30 to the one far from the light source unit 30, so that the frame 16 is translucent according to the distance from the light source unit 30. Can be provided.

  As shown in FIGS. 3 to 5, the reflection sheet RE is attached to the lower surface SF1 of the frame 16 by the first diffusion adhesive layer 24a and covers the lower surface side of the frame 16. The reflection sheet RE has a thickness of 200 μm or less, preferably 50 to 90 μm, and a reflectance of 90% or more, preferably 95% or more. Further, the reflection sheet RE has an outer shape of the frame 16 both when viewed at intervals between the long side portions 16a and 16b of the frame 16 and when viewed at intervals between the short side portions 16c and 16d of the frame 16. The reflective sheet RE is formed in a rectangular shape having a size equal to the dimension, and the outer surface (outer edge) of the reflection sheet RE is flush with the outer surface (outer edge) of the frame 16, and one of them projects toward the other. Not in a state of

  The backlight unit 20 has, as an optical member housed in the frame 16, a light guide plate LG having a rectangular shape in a plan view, and an optical sheet OS arranged on the light guide plate LG in an overlapping manner. Further, the backlight unit 20 includes a light source unit 30 that is provided along one side surface (incident surface) EF of the light guide plate LG and emits light toward the light guide plate LG.

  The light guide plate LG is made of a translucent resin in an extremely thin rectangular shape, and has a rectangular parallelepiped shape. The light guide plate LG has a first main surface S1 serving as an emission surface, a second main surface S2 opposite to the first main surface S1, and an incident surface EF connecting the first main surface S1 and the second main surface S2. And are equipped with. In the present embodiment, one side surface on the short side of the light guide plate LG is used as the incident surface EF. The light guide plate LG is formed to have an outer dimension (length, width) slightly smaller than the inner dimension of the frame 16 and a dimension slightly larger than the display area DA of the liquid crystal display panel 12 in plan view. There is. Regarding the plate thickness of the light guide plate LG, the thickness on one side face (incident surface) facing the light source unit 30 is the largest, and the thickness on the other side face that is the opposite side to the one side face is the smallest. In this embodiment, as the thickness of the light guide plate LG, the thickness of the other side surface is set to, for example, about 0.2 to 0.5 mm (200 to 500 μm). According to the present embodiment, the thickness T1 of the frame 16 is formed thinner than the thinnest portion of the light guide plate LG. Then, the total of the thickness of the light guide plate LG and the thickness of the optical sheets OS is substantially equal to the total of the thickness T1 of the frame 16 and the thicknesses T2 and T3 of the first diffusion adhesive layer and the second diffusion adhesive layer. Has become. That is, the total thickness of the light guide plate LG and the optical sheet OS is formed to be, for example, 0.36 to 0.52 mm (360 to 520 μm). Furthermore, it is also possible to use an extremely thin light guide plate LG having a plate thickness of 0.2 mm (200 μm) or less. The light guide plate LG is placed on the reflection sheet RE such that the second main surface S2 faces the reflection sheet RE. The incident surface EF of the light guide plate LG faces the short side portion 16d of the frame 16. The other side surface of the light guide plate LG faces the short side portion 16c and the long side portions 16a and 16b of the frame 16 with a slight gap of about 0.05 to 0.2 mm (50 to 200 μm).

  The optical sheet OS has a light-transmitting property and is placed on the first main surface S1 of the light guide plate LG in an overlapping manner. In this embodiment, as the optical sheet OS, for example, a diffusion sheet OS1 and a prism sheet OS2 formed of a synthetic resin such as polyethylene terephthalate are used. These optical sheets OS are sequentially stacked and placed on the first main surface S1 of the light guide plate LG. Each optical sheet OS is formed to have the same width as the width of the light guide plate LG and a length slightly shorter than the length of the light guide plate LG in plan view, and slightly smaller than the display area DA of the liquid crystal display panel 12. It has a large size. At least three side edges of the optical sheet OS excluding the side edge on the light source side directly face the frame 16 with a predetermined gap (0.1 to 0.5 mm). The optical sheet OS faces the back surface of the liquid crystal display panel 12 with a slight gap. As a result, the optical sheet OS faces the entire display area DA of the liquid crystal display panel 12.

  As shown in FIGS. 3 and 5, the light source unit 30 includes an elongated strip-shaped printed circuit board (FPC) 32 and a light source mounted on the printed circuit board 32. According to this embodiment, as the light source, for example, light emitting diodes (LEDs) 34, which are point light sources, are arranged at a predetermined interval. Each of the plurality of LEDs 34 has an emission surface 34a and a mounting surface 34b perpendicular to the emission surface 34a. The plurality of LEDs 34 are arranged side by side at predetermined intervals along the longitudinal direction of the printed circuit board 32 (direction parallel to the short side portion of the frame 16). Each LED 34 is mounted with the mounting surface 34b facing the printed circuit board 32. The printed circuit board 32 also has a connection end 32a extending from one side edge.

One long side portion of the printed circuit board 32 is overlapped with the short side portion 16d of the frame 16 by the second diffusion adhesive layer 24b, and the other long side portion is on the end portion of the light guide plate LG on the incident surface EF side. positioned. Thereby, the plurality of LEDs 34 are arranged between the short side portion 16d of the frame 16 and the incident surface EF of the light guide plate LG, and the emission surface 34a of each LED 34 faces the incident surface EF. In the present embodiment, the LED 34 is arranged in the recess 17 of the short side portion 16d. The height (thickness) Lh of each LED 34 is, for example, preferably 0.4 mm (400 μm) or less, and more preferably 0.3 mm (300 μm) or less.
As the light source, a fluorescent tube or a cathode ray tube as a line light source can be adopted. Alternatively, as the light source, a line light source or a surface light source in which a light source made of an organic EL is extremely densely arranged can be adopted.

As shown in FIG. 5, a fourth adhesive layer, for example, a double-sided tape 37 is attached to the end of the optical sheet OS2 on the light source side and the end of the printed circuit board 32 on the optical sheet side. . Further, one end portion of the lowermost optical sheet OS1 on the light source side extends beyond the one end portion of the optical sheet OS2 to the light source side and is attached to the double-sided tape 37. As a result, the optical sheets OS1 and OS2 are bonded to the printed circuit board 32 by the double-sided tape 37.
Further, as shown in FIGS. 3 and 5, a third strip-shaped third adhesive layer, for example, the double-sided tape 36 is laminated and attached on the printed circuit board 32 and the end portion of the optical sheet OS.

The backlight unit 20 configured as described above is disposed so as to face the back surface of the liquid crystal display panel 12, and is attached to the polarizing plate PL2 of the liquid crystal display panel 12 by the second diffusion adhesive layer 24b and the double-sided tape 36. There is.
That is, the pair of long side portions 16a and 16b of the frame 16 are respectively attached to the long side end portions of the back surface of the polarizing plate PL2 by the second diffusion adhesive layer 24b, whereby the long side portions of the polarizing plate PL2 are aligned. It becomes a state. The short side portion 16c of the frame 16 is affixed to the short side end portion of the back surface of the polarizing plate PL2 by the second diffusion adhesive layer 24b and is in a state along the short side of the polarizing plate PL2. As a result, the long side portions 16a and 16b and the short side portion 16c of the frame 16 are positioned in the thickness direction of the liquid crystal display panel 12, that is, in a plan view, overlapping the frame region ED of the liquid crystal display panel 12. At the same time, they are flush with the pair of long sides and one short side of the polarizing plate PL2.
In the present embodiment, on the three sides of the frame 16 excluding the light source side, the ends of the polarizing plate are flush with the ends of the liquid crystal display panel, or positioned inside the ends of the liquid crystal display panel. A configuration can be adopted.

  The printed circuit board 32 attached to the other short side portion 16d of the frame 16 is attached not to the polarizing plate PL2 but to the back surface side of the first insulating substrate SUB1 of the liquid crystal display panel 12 by the double-sided tape 36. As a result, the short side portion 16d of the frame 16 and the light source unit 30 are positioned so as to overlap the frame region ED of the liquid crystal display panel 12 and the light shielding layer RS of the cover panel 14.

  The optical sheets OS1 and OS2 and the light guide plate LG face the display area DA of the liquid crystal display panel 12. The printed circuit board 32 of the light source unit 30 is connected to the FPC 22 via the connection end 32a (see FIG. 2). As a result, the drive current is applied to the LED 34 via the FPC 22 and the printed circuit board 32. The light emitted from the LED 34 enters the light guide plate LG from the incident surface EF of the light guide plate LG and propagates in the light guide plate LG. This light is once emitted from the second main surface S2 of the light guide plate LG, is then reflected by the reflection sheet RE, and enters the light guide plate LG again. After passing through such an optical path, the light from the LED 34 is emitted from the first main surface (emission surface) S1 to the liquid crystal display panel 12 side. The emitted light is diffused by the optical sheet OS, and then applied to the display area DA of the liquid crystal display panel 12.

  Further, the light leaked from the pair of long side surfaces of the light guide plate LG and the short side surface opposite to the incident surface EF is incident on the long side portions 16 a and 16 b and the short side portion 16 c of the frame 16. And propagates in the frame 16. Further, this light is emitted from the lower surface SF1 of the frame 16 to the first diffusion adhesive layer 24a, is then reflected by the reflection sheet RE, and is incident on the first diffusion adhesive layer 24a and the frame 16 again. After passing through such an optical path, the light incident on the frame 16 is diffused by the second diffusion adhesive layer 24b, emitted from the second diffusion adhesive layer 24b to the liquid crystal display panel 12 side, and the periphery of the liquid crystal display panel 12 is emitted. The area is irradiated. Thus, the frame 16 and the first and second diffusion adhesive layers 24a and 24b function as an auxiliary light source unit that irradiates the liquid crystal display panel 12 side with the light leaked to the periphery of the light guide plate LG. As described above, the backlight unit 20 can irradiate the liquid crystal display panel 12 with light from the entire first major surface S1 of the light guide plate LG and the frame 16 located around the light guide plate LG. Therefore, for example, even when the display surface of the liquid crystal display panel 12 is viewed from an oblique direction, it is possible to prevent a problem such as the peripheral portion of the display area DA becoming dark.

Next, an example of a method of manufacturing the backlight unit (backlight device) 20 having the above configuration will be described. FIG. 7 is a diagram schematically showing an example of a manufacturing apparatus and all manufacturing steps, and FIGS. 8 to 12 are perspective views each schematically showing a state of a sheet in each manufacturing step.
As shown in FIG. 7, the manufacturing apparatus includes a plurality of rolls RP, RA1, RA2a, RA2b, RS1, RS2, RR, each of which is formed by winding a long sheet-shaped material, and a sheet material drawn from these rolls. A pair of first transport rollers 80a and 80b that transport along the transport path CP, a pair of second transport rollers 82a and 82b, a recovery roll RC that winds and collects the separator, and a sheet material that moves along the transport path CP are punched. A first punching machine P1 and a second punching machine P2 are provided.

  The plurality of rolls include a sheet material for forming a frame, for example, a roll RP wound with a PET sheet 50, a roll RA1 wound with a first diffusion adhesive layer, and a roll RA2a wound with a second diffusion adhesive layer. , RA2b, and rolls RS1 and RS2 wound with separators, respectively. In the present embodiment, as the first diffusion adhesive layer and the second diffusion adhesive layer, only the diffusion adhesive layer or the substrate + adhesive is used. A double-sided tape may be used as the diffusion adhesive layer. The width of each roll is equal to the outer dimension between the short sides of the backlight unit. Only the roll RA2b has a width slightly smaller than the other rolls.

  As shown in FIG. 7, first, a sheet material drawn from rolls RP, RA1, RA2a, RA2b, RS1, RS2, for example, PET sheet 50, first diffusion adhesive layer 24a, second diffusion adhesive layer 24b1, second sheet. The diffusion adhesive layer 24b2 and the separator are conveyed between the pair of conveying rollers 80a and 80b to be laminated and attached to each other. That is, as shown in FIGS. 8 and 9, the first diffusion adhesive layer 24a is attached to the entire lower surface (first surface) of the PET sheet 50. Further, on the upper surface (second surface) of the PET sheet 50, the second diffusion adhesive layer 24b1 is stuck on the entire surface, and further, the second diffusion adhesive layer 24b2 is formed on the area except the predetermined area along one side portion. Affix. The first diffusion pressure-sensitive adhesive layer 24a and the second diffusion pressure-sensitive adhesive layer 24b2 are covered with a separator on the surface opposite to the surface attached to the PET sheet 50.

  Next, as shown in FIGS. 7 and 10, the first punching machine (die etc.) P1 is used to bring together the first diffusion adhesive layer 24a, the sheet material 50, the second diffusion adhesive layers 24b1, 24b2 and the separator. Punching is performed to sequentially form rectangular inner holes 52a and 52b corresponding to the inner shape (inner hole) of the frame. Subsequently, the separator on the first diffusion adhesive layer 24a is peeled off and wound by a collecting roll RC to be collected. In this state, as shown in FIGS. 7 and 11, the reflection sheet RE pulled out from the roll RR is attached to the entire surface of the first diffusion adhesive layer 24a. The sheet material 50, the diffusion adhesive layer, and the reflection sheet RE are conveyed between the pair of conveying rollers 82a and 82b along the conveying path CP.

  After that, as shown in FIGS. 7 and 12, the second punching machine (die etc.) P2 is used for the first diffusion adhesive layer 24a, the sheet material 50, the second diffusion adhesive layers 24b1, 24b2, and the second diffusion adhesive layer. The separator on 24b2 and the reflection sheet RE are punched together, and the outer shapes of the frame 16, the reflection sheet RE, and the first and second diffusion adhesive layers are collectively formed. As a result, the frame 16 provided with the reflection sheet RE and the diffusion adhesive layer is sequentially produced. Subsequently, as shown in FIG. 7, the light guide plate LG, the optical sheet OS, and the light source unit 30 are mounted and fixed to the formed frame 16, so that the backlight unit 20 is obtained. The light guide plate LG, the optical sheet OS, and the light source unit 30 may be unitized in advance by bonding them to each other with a diffusion adhesive layer, for example, a double-sided tape.

  According to the liquid crystal display device 10 and the backlight unit 20 according to the present embodiment configured as described above, the frame 16 located around the light guide plate LG serves as an auxiliary light source unit that emits light to the liquid crystal display panel 12 side. It can be made to function, and it becomes possible to irradiate the effective display area DA of the liquid crystal display panel 12 and the frame area (non-display area) ED around the effective display area DA. Therefore, for example, even when the liquid crystal display panel 12 is viewed from an oblique direction, it is possible to suppress a defect such as the peripheral portion of the display area DA becoming dark. As a result, it is possible to realize a liquid crystal display device having a narrower frame than the conventional one. That is, in the three side portions other than the side portion adjacent to the light source unit 30, the effective illumination area can be substantially the outer shape of the backlight unit 20 including the frame 16, and the liquid crystal display device 10 having a narrower frame. Can be realized.

  Further, according to the present embodiment, a thin sheet material having a thickness of 0.4 mm (400 μm) or less, for example, a thickness of 0.15 to 0.25 mm (150 to 255 μm) is punched to form the backlight frame 16. As a result, it is possible to obtain the frame 16 that is thin and has a small side width, which is difficult to produce by injection molding. By using this frame 16, a backlight device and a liquid crystal display device which are thinner and have a narrower frame can be realized at low cost. For example, the thickness of the frame 16 can be set to 0.2 mm or less and the width of the side portion can be set to 0.45 mm or less, and a thin and narrow frame can be easily realized. Further, by making the frame 16 thin, it becomes possible to use an extremely thin light guide plate having a plate thickness of 0.2 mm or less, and a thinner backlight device can be obtained.

Further, the sheet, the diffusion adhesive layers 24a and 24b formed on or affixed to the sheet, and the reflection sheet RE are punched together with the frame 16 so that the width of the diffusion adhesive layer and the external dimensions of the reflection sheet RE can be determined. Can be matched with high precision.
In the case of the comparative example in which the diffusion adhesive layer is post-applied or post-applied to the frame 16 as compared with the present embodiment, it is difficult to provide the diffusion adhesive layer on the upper and lower surfaces of the frame so as to match the frame width because the frame width is extremely narrow. Yes, the diffusion adhesive layer will stick out. Such an adhesive that sticks out not only adversely affects the subsequent process, but also adheres to other components of the backlight device, which leads to a reduction in the light emitting performance of the backlight device. On the other hand, in the backlight device of the present embodiment, the widths of the diffusion adhesive layers 24a and 24b are matched with the widths of the side portions of the frame 16, and the side surfaces (side edges) of the diffusion adhesive layers 24a and 24b are set to the frame 16. Can be flush with the side surface (side edge) of. As a result, in this embodiment, the dimensional accuracy of the backlight device is improved. Further, after the sheet 50, the diffusion adhesive layers 24a and 24b, and the reflection sheet RE are integrated by a so-called roll-to-roll manufacturing method, they are collectively punched. With such a manufacturing method, the manufacturing process can be simplified and mass production can be realized, the accuracy of each member can be improved, and further, the tolerance between the respective members which is required when these are separately formed is reduced. As a result, the present embodiment can contribute to thinning and narrowing of the frame.

  Although the frame 16 is made of the resin sheet material in the above-described first embodiment, the frame 16 is not limited to this, and a transparent resin mold frame may be used. Even in this case, the frame 16 can be used as an auxiliary light source.

  Next, a liquid crystal display device and a backlight device according to another embodiment or modification will be described. In other embodiments and modifications described below, the same parts as those in the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted or simplified, and the first embodiment will be described. A detailed description will be given centering on portions different from the embodiment.

(Second embodiment)
FIG. 13 is a horizontal cross-sectional view of the liquid crystal display device according to the second embodiment, and FIG. 14 is a vertical cross-sectional view of the liquid crystal display device according to the second embodiment.
As shown in FIGS. 13 and 14, according to the present embodiment, in the liquid crystal display device 10, the optical sheet OS of the backlight unit 20 is provided on the second surface SF2 of the frame 16 via the second diffusion adhesive layer 24b. It is attached. The optical sheet OS faces the light guide plate LG with a gap. The optical sheet OS includes a diffusion sheet OS1 attached to the upper surface SF2 of the frame 16 via the second diffusion adhesive layer 24b, and a prism sheet OS2 arranged so as to overlap the diffusion sheet OS1. The prism sheet OS2 is in contact with the polarizing plate PL2 of the liquid crystal display panel 12, that is, in surface contact with the entire surface of the polarizing plate PL2. The polarizing plate PL2 is attached to the back surface of the second substrate SUB2 by the diffusion adhesive layer 40 containing fine beads.

In the long side portions 16a and 16b and the short side portion 16c of the frame 16, the outer surface (outer edge) of the frame 16 and the outer surfaces of the diffusion sheet OS and the prism sheet OS2 are flush with each other. Further, at the long side portions 16a and 16b and the short side portion 16c of the frame 16, the outer surface (outer edge) of the frame 16 and the outer surface of the polarizing plate PL2 of the liquid crystal display panel 12 and the first and second insulating substrates SUB1, The outer surface of the SUB2 is flush with the outer surface. The width W1 of the long side portions 16a and 16b and the width W2 of the short side portion 16c of the frame 16 match the width of the frame area ED of the liquid crystal display panel 12, respectively. As a result, the long side portions 16 a and 16 b and the short side portion 16 c of the frame 16 are positioned so as to overlap the entire frame region ED of the liquid crystal display panel 12 in the thickness direction of the liquid crystal display panel 12.
The unevenness of the diffusion sheet OS1 is filled with the second diffusion adhesive layer 24b, the difference in refractive index is small at the interface between the diffusion sheet OS1 and the second diffusion adhesive layer 24b, and light diffusion at the interface is reduced. However, due to the diffusivity of the second diffusion adhesive layer 24b, light can be favorably diffused from the frame 16 to the diffusion sheet OS2 and the prism sheet OS1 side via the second diffusion adhesive layer 24b.

  According to the second embodiment configured as described above, it is not necessary to consider the tolerance between the frame and the optical sheet. As a result, it becomes possible to dispose the frame 16 functioning as a light source inside the liquid crystal display panel 12, that is, at a position closer to the effective display area DA than in the above-described first embodiment. As a result, the frame of the liquid crystal display device can be further narrowed. Further, even when the diffusion sheet and the prism sheet are integrated with the polarizing plate PL2 of the liquid crystal display panel 12, the light diffusion function is provided to the diffusion adhesive layer 40 between the polarizing plate PL2 and the second insulating substrate SUB2 of the liquid crystal display panel 12. By having the diffusion sheet OS1, the reduction of the diffusion function of the diffusion sheet OS1 can be offset, and the display unevenness when visually recognized from the cover panel 14 side can be reduced. The diffusion adhesive layer 40 has a size that does not extend beyond the polarizing plate PL2 to prevent unwanted light from wrapping around. In addition, also in the second embodiment, it is possible to obtain the same effect as that of the first embodiment described above.

(Third Embodiment)
FIG. 15 is a horizontal cross-sectional view of the liquid crystal display device according to the third embodiment, and FIG. 16 is a vertical cross-sectional view of the liquid crystal display device according to the third embodiment.
As shown in FIGS. 15 and 16, according to the present embodiment, the frame 16 functioning as a light source is arranged further inside the liquid crystal display panel 12, that is, up to the effective display area DA side. The pair of long side portions 16a and 16b of the frame 16 and the short side portion 16c on the side opposite to the light source unit 30 overlap the frame region (non-display region) ED of the liquid crystal display panel 12 in the thickness direction of the liquid crystal display panel 12. In addition, the inner edge portion facing the light guide plate LG overlaps the effective display area DA.
In the third embodiment, other configurations of the liquid crystal display device 10 are the same as those of the liquid crystal display device 10 according to the second embodiment described above.
According to the third embodiment configured as described above, by using the frame 16 functioning as a light source, the frame 16 is arranged inside the liquid crystal display panel 12 to a position overlapping the effective display area DA. It becomes possible. As a result, the frame of the liquid crystal display device can be further narrowed. Further, since the frame 16 and the effective display area DA may be provided so as to overlap with each other, when the liquid crystal display device is manufactured, it is possible to allow a certain amount of misalignment of the backlight unit 20 to the liquid crystal display panel 12. Thereby, the assembling property or the manufacturability of the liquid crystal display device can be improved. In addition, also in the third embodiment, it is possible to obtain the same effects as those of the first embodiment described above.

(Fourth Embodiment)
FIG. 17 is a horizontal cross-sectional view of the liquid crystal display device according to the fourth embodiment, and FIG. 18 is a vertical cross-sectional view of the liquid crystal display device according to the fourth embodiment.
As shown in FIGS. 17 and 18, according to the present embodiment, the reflection sheet RE of the backlight unit 20 has a plurality of extension end portions REE extending outward beyond the outer peripheral edge of the frame 16. ing. These extended end portions REE are bent toward the cover panel 14 side and attached to the outer surface of the frame 16 and the outer surface of the liquid crystal display panel 12. In the present embodiment, at the pair of long side portions 16a, 16b and short side portion 16c of the frame 16, the outer surface of the frame 16, the outer surface of the first and second diffusion adhesive layers 24a, 24b, and the liquid crystal display panel. The outer surface of 12 is covered with the extended end portion REE of the reflection sheet RE. Thus, the light leaked from the outer surface of the frame 16, the outer surfaces of the first and second diffusion adhesive layers 24a and 24b, and the outer surface of the optical sheet OS is reflected by the extended end portion REE of the reflection sheet RE. The liquid crystal display panel 12 side can be irradiated with the light by returning it to the inside of the frame 16 and the inside of the first and second diffusion adhesive layers 24a and 24b. Thereby, the light utilization efficiency of the backlight unit 20 can be improved.
In addition, in the fourth embodiment, the other configuration of the liquid crystal display device 10 is the same as that of the second embodiment or the third embodiment described above.

(Fifth Embodiment)
19 is a perspective view showing the liquid crystal display device according to the fifth embodiment, and FIG. 20 is a cross-sectional view of the liquid crystal display device taken along the line CC of FIG.
Since the liquid crystal display device of this embodiment is extremely thin, at least a part of the liquid crystal display device can be curved in the out-of-plane direction. As shown in FIGS. 19 and 20, in the fifth embodiment, both ends on the long side of the liquid crystal display device 10 form a curved portion CA that is curved downward, that is, on the backlight device 20 side. There is.

  In one example, both ends of the cover panel 14 on the long side are curved and formed in advance on the backlight device 20 side. The liquid crystal display panel 12 including the polarizing plates PL1 and PL2 is attached to the cover panel 14 with an adhesive sheet AD made of an optical transparent resin. As a result, both ends on the long side of the liquid crystal display panel 12 are curved along the cover panel 14. In the present embodiment, both ends on the long side of the liquid crystal display panel 12 extend to positions flush with both ends on the long side of the cover panel 14. The degree of bending of the bending portion CA, for example, the radius of curvature can be arbitrarily adjusted.

  In the backlight unit 20, the optical sheet (diffusion sheet) OS1 is placed on the light guide plate LG and arranged inside the frame 16. The optical sheet (prism sheet) OS2 is placed on the optical sheet OS1, and the peripheral portion of the optical sheet OS2 is attached to the second surface SF2 of the frame 16 via the second diffusion adhesive layer 24b. In the present embodiment, the outer dimensions of the optical sheet OS2 are formed slightly smaller than the outer dimensions of the frame 16. As a result, the side edges on the long side of the optical sheet OS2 are located inside the outer edges of the long side portions 16a and 16b of the frame 16.

The backlight unit 20 is provided so as to face the flat portion of the liquid crystal display panel 12. The light guide plate LG and the optical sheet OS1 face the display area DA of the liquid crystal display panel 12. The peripheral portion of the optical sheet OS2, that is, the portion overlapping the frame 16 is attached to the polarizing plate PL2 by the transparent diffusion adhesive layer 40. As a result, the backlight unit 20 is attached to the liquid crystal display panel 12. The diffusion adhesive layer 40 contains fine beads and has a light diffusing property. The diffusion adhesive layer 40 is provided on the surface of the polarizing plate PL2 in the deflecting plate PL2 from a position facing the frame 16 to a position facing the inner edge of the seal material SE.
The curved portion CA of the cover panel 14 and the liquid crystal display panel 12 extends outward beyond both side edges on the long side of the frame 16 to cover the outer side surface 16f of the frame 16 and is oblique to the outer side surface 16f. Facing each other. The backlight unit 20 is also formed in a flat plate shape and does not project to the curved portion CA. By mounting the backlight unit 20 in this state, the edge portion of the frame 16 of the backlight unit 20 faces the curved portion CA. That is, the edge portion of the frame 16 that functions as an auxiliary light source of the backlight unit 20 faces the curved portion CA.

According to the fifth embodiment configured as described above, by bending both ends on the long side of the liquid crystal display panel 12 to form the curved portions CA, the panel design can be diversified. Therefore, it is possible to expand the range of use of the liquid crystal display device. Further, by extending both side edges of the liquid crystal display panel 12 beyond the frame 16 to the side edges of the cover panel 14, the effective display area DA of the liquid crystal display panel 12 can be expanded by the area DA2. That is, according to the present embodiment, the frame 16 located around the light guide plate LG can function as an auxiliary light source unit that irradiates the liquid crystal display panel 12 side with light, so that the display located outside the light guide plate LG can be displayed. It is also possible to irradiate the area DA2 with light from the frame 16. Therefore, the display area DA2 can be used as an effective display area to display an image. In this way, the effective illumination area can be set up to the outside of the backlight unit 20 substantially including the frame 16 at both side edges on the long side of the liquid crystal display panel 12, and the liquid crystal display device with a narrower frame. 10 can be realized.
In addition, also in the fifth embodiment, it is possible to obtain the same effects as the first embodiment described above. In addition, in the fifth embodiment, the bending portion is not limited to the both side portions on the long side, and the entire liquid crystal display device may be bent.

(First modification)
FIG. 21 is a cross-sectional view showing a part of the liquid crystal display device according to the first modification.
In the fifth embodiment described above, the frame 16 of the backlight unit 20 may be wide and a part of the frame 16 may be curved along the liquid crystal display panel 12.
As shown in FIG. 21, in the first modification, the long side portions 16a and 16b of the frame 16 are formed to be wide, respectively, from the vicinity of the side edge of the light guide plate LG to the vicinity of the inner edge of the seal material SE of the liquid crystal display panel 12. It has been extended. The peripheral portion of the reflection sheet RE is attached to the lower surface SF1 of the frame 16 by the first diffusion adhesive layer 24a and covers the lower surface SF1 of the frame 16. The peripheral portion of the optical sheet (prism sheet) OS2 is attached to the upper surface SF2 of the frame 16 by the second diffusion adhesive layer 24b and covers the upper surface SF2 of the frame 16. In this modification, the side edge of the reflection sheet RE and the side edge of the optical sheet OS2 are flush with the outer surface of the frame 16.

The peripheral portions of the frame 16 and the optical sheet OS2 are attached to the polarizing plate PL2 of the liquid crystal display panel 12 by a light-diffusing diffusion adhesive layer 40. As a result, the frame 16, the peripheral edge of the reflective sheet RE, and the peripheral edge of the optical sheet OS2 are curved along the liquid crystal display panel 12 and face the curved portion CA of the liquid crystal display panel 12 and the display area DA2.
According to the first modified example, by providing the frame 16 functioning as an auxiliary light source over the entire curved portion CA and the display area DA2, it is possible to irradiate the display area DA2 with more light. Even in this case, since the frame 16 functions as an auxiliary light source, it does not hinder the narrowing of the frame of the liquid crystal display device. Further, since the display area DA2 is irradiated with the light from the auxiliary light source, it is considered that the brightness is slightly lower than that of the display area DA. On the other hand, it is assumed that the display area DA2 including the curved portion CA is used for auxiliary use such as a sub window when the display area DA is the main window. When the display area DA2 is used as such an auxiliary use, it is effectively used even in a state where the brightness is lower than that of the display area DA.

(Second modified example)
FIG. 22 is a sectional view showing a part of the liquid crystal display device according to the second modification.
In this modification, only the peripheral edge of the optical sheet OS2 extends to the vicinity of the seal material SE of the liquid crystal display panel 12, and is attached to the polarizing plate PL2 by the diffusion adhesive layer 40. The long side portions 16a and 16b of the frame 16, the first diffusion adhesive layer 24a, the second diffusion adhesive layer 24b, and the peripheral portion of the reflection sheet RE are formed to be slightly shorter than the optical sheet OS2 and extend to the front of the seal material SE. Existence
Even in such a configuration, the light emitted from the frame 16 can be diffused by the optical sheet OS2 and the diffusion adhesive layer 40 and can be applied to the entire display area DA2. Moreover, since the width of the backlight unit 20 can be reduced, it contributes to downsizing of the entire liquid crystal display device.

  Although some embodiments and modifications of the present invention have been described, these embodiments and modifications are presented as examples and are not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. The embodiments and modifications thereof are included in the scope and the gist of the invention, and are also included in the invention described in the claims and an equivalent range thereof.

Based on the configurations and manufacturing steps described above as the embodiments of the present invention, all configurations and manufacturing steps that can be implemented by those skilled in the art by appropriately changing the design are also included in the scope of the present invention as long as they include the gist of the present invention. Belong to. For example, it is possible to adopt a configuration in which the liquid crystal display panel is not first attached to the cover panel, but is housed in the housing case housing the backlight unit and then mounted to the cover panel together with the flange of the housing case. It is also possible to adopt a configuration in which the liquid crystal display panel is not adhered to the cover panel and can be slightly moved within the housing case. Further, it is also possible to adopt a configuration in which the liquid crystal display panel is fixed to the backlight unit and the backlight unit and the liquid crystal display panel fixed to each other are housed in a housing case.
Further, it is understood that other actions and effects which are brought about by the above-described embodiments are apparent from the description of the present specification, or those which can be appropriately conceived by those skilled in the art, are brought about by the present invention.

  The number of optical sheets of the backlight unit is not limited to two, and may be increased or decreased as necessary. The outer shape and the inner shape of the liquid crystal display panel, the constituent members of the backlight unit, and the frame are not limited to the rectangular shape, and either one or both of the outer shape and the inner diameter may be formed. Other shapes such as a polygonal shape in plan view, a circle, an ellipse, and a combination thereof may be used. The materials of the constituent members are not limited to the above-mentioned examples, and various selections can be made.

10 ... Liquid crystal display device, 12 ... Liquid crystal display panel, 14 ... Cover panel,
16 ... Frame, 20 ... Backlight unit (backlight device),
22 ... Flexible printed circuit board (FPC), 24a ... First diffusion adhesive layer,
24b ... 2nd diffusion adhesive layer, 30 ... Light source unit, 32 ... Printed circuit board (FPC),
34 ... LED, 36 ... Double-sided tape (third adhesive layer), 50 ... Sheet material,
SUB1 ... First substrate, SUB2 ... Second substrate, LQ ... Liquid crystal layer, DA ... Display area,
ED ... Frame area (non-display area), 24 ... Double-sided tape, LG ... Light guide plate,
OS ... Optical sheet, PL1, PL2 ... Polarizing plate

Claims (22)

A frame-shaped frame made of transparent resin,
A first diffusion adhesive layer provided on the first surface of the frame and having a light diffusing property;
A second diffusing adhesive layer provided on the second surface of the frame opposite to the first surface and having a light diffusing property;
A reflection sheet attached to the frame via the first diffusion adhesive layer;
A light guide plate placed on the reflection sheet in the frame,
A backlight device comprising: a light source that is disposed in the frame and that allows light to enter the light guide plate.   The backlight device according to claim 1, further comprising an optical sheet disposed on the light guide plate in the frame.   The backlight device according to claim 1, further comprising an optical sheet that is attached to the frame via the second diffusion adhesive layer and faces the light guide plate.   The backlight device according to claim 3, wherein the optical sheet includes a diffusion sheet attached to the frame via the second diffusion adhesive layer, and a prism sheet provided so as to overlap the diffusion sheet. .   The first diffusion pressure-sensitive adhesive layer and the second diffusion pressure-sensitive adhesive layer are formed of a pressure-sensitive adhesive containing fine beads having a refractive index different from that of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer. Backlight device described.   The backlight device according to claim 5, wherein the first diffusion adhesive layer has a higher diffusivity than the second diffusion adhesive layer.   The frame is formed of a transparent resin sheet material, and the width of the frame and the width of the first diffusion adhesive layer are the same in at least a part of the frame, and at least the outer surface of the frame and the first diffusion adhesive layer. The backlight device according to claim 1, wherein the outer surface of the layer is flush with the outer surface.   The backlight device according to claim 7, wherein an outer surface of the reflection sheet is flush with the outer surface of the first diffusion adhesive layer and the frame in at least a part of the first diffusion adhesive layer.   The backlight device according to claim 7, wherein the frame has a thickness of 0.4 mm or less. The frame has at least four sides,
The diffusivity of the first diffusion adhesive layer provided on the side portion opposite to the side portion adjacent to the light source is higher than the diffusivity of the first diffusion adhesive layer provided on the other side portion. The backlight device according to claim 1, wherein the backlight device is high.   The backlight device according to claim 1, wherein the reflection sheet has an extended end portion that covers an outer surface of the frame and outer surfaces of the first and second diffusion adhesive layers. LCD display panel,
The backlight device according to claim 1, which is arranged so as to face the liquid crystal display panel, and a liquid crystal display device.   The frame of the backlight device is attached to the liquid crystal display panel via the second diffusion adhesive layer, and the backlight device includes an optical sheet arranged on the light guide plate in the frame. The liquid crystal display device according to claim 12.   The liquid crystal display device according to claim 12, wherein the backlight device includes an optical sheet attached to the frame via the second diffusion adhesive layer, and the optical sheet is in contact with the liquid crystal display panel.   The optical sheet includes a diffusion sheet attached to the frame via the second diffusion adhesive layer, and a prism sheet provided so as to overlap the diffusion sheet, and the prism sheet is provided on the liquid crystal display panel. The liquid crystal display device according to claim 14, which is in contact with the liquid crystal display device.   The liquid crystal display panel has an effective display area and a non-display area located around the effective display area, and the frame of the backlight device has the non-display area in a thickness direction of the liquid crystal display panel. 16. The liquid crystal display device according to claim 12, wherein the liquid crystal display device is located so as to overlap with the area and at least partly overlaps with the effective display area.   The liquid crystal display device according to claim 12, wherein the first diffusion adhesive layer is formed of an adhesive containing microbeads having a different refractive index from the adhesive forming the adhesive layer.   The second diffusion pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive containing fine beads having a different refractive index from the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, and the first diffusion pressure-sensitive adhesive layer has a higher diffusion than the second diffusion pressure-sensitive adhesive layer. The liquid crystal display device according to claim 17, which has a property.   The frame is formed of a transparent resin sheet material, and the width of the frame and the width of the first diffusion adhesive layer are the same in at least a part of the frame, and at least the outer surface of the frame and the first diffusion adhesive layer. The liquid crystal display device according to claim 12, wherein the outer surface of the layer is flush with the outer surface of the layer.   20. The liquid crystal display device according to claim 12, wherein at least a part of the liquid crystal display panel has a curved portion that is curved toward the backlight device. The liquid crystal display panel has a pair of long sides facing each other and a pair of short sides facing each other, and a side edge portion of the liquid crystal display panel on the long side is a curved portion curved toward the backlight device. To form
The liquid crystal display device according to claim 20, wherein the frame has a long side portion facing the curved portion.   22. The liquid crystal display device according to claim 21, wherein the long side portion of the frame is attached to the curved portion via an optical sheet and a diffusion adhesive layer, and is curved along the curved portion.

Images