Video display device, backlight unit, and electronic device

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2010-288061, filed Dec. 24, 2010, the entire contents of which are incorporated herein by reference.

Embodiments described herein relate generally to a video display device, a backlight unit, and an electronic device.

There have been known video display devices provided with a light guide plate and a plurality of light emitting diodes (LEDs) as a backlight. The light guide plate is located behind the display module, while the LEDs are located to face the side edge of the light guide plate.

If this type of video display device is provided with a plurality of components each having a plurality of LEDs, and if the components have different structures (specifications) depending on their locations, this may arise some inconvenience such as an increase in the number of components and manufacturing process.

A general architecture that implements the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention.

FIG. 1 is an exemplary front view of a video display device according to an embodiment;

FIG. 2 is an exemplary side view of the video display device in the embodiment;

FIG. 3 is an exemplary back view of the video display device without a back cover in the embodiment;

FIG. 4 is an exemplary schematic exploded perspective view of a portion of the main body of the video display device in the embodiment;

FIG. 5 is an exemplary schematic back view illustrating the arrangement of a light guide and a plurality of components of the video display device in the embodiment;

FIG. 6 is an exemplary perspective view of a component of the video display device in the embodiment;

FIG. 7 an exemplary schematic diagram for explaining the circuit structure and the arrangement of connector terminals in the components in the embodiment;

FIG. 8 is an exemplary schematic back view illustrating the arrangement of the fourth connector in a circuit board of the video display device in the embodiment;

FIG. 9 is another exemplary schematic back view illustrating the arrangement of the light guide and the components of the video display device in the embodiment;

FIG. 10 is another exemplary schematic back view illustrating the arrangement of the fourth connector in the circuit board of the video display device in the embodiment; and

FIG. 11 is an exemplary schematic cross-sectional view of a plurality of flat cables overlapped in the thickness direction of the video display device according to a modification of the embodiment.

In general, according to one embodiment, a video display device comprises a housing, a display module, a light guide, two first components, and two second components. The display module comprises a display screen and is configured to be at least partly housed in the housing. The light guide is located opposite the display screen with respect to the display module. The two first components each comprise a base portion, a plurality of light emitters, and a connector. The base portion is arranged along an edge of the light guide. The light emitters are arranged on the base portion to face the edge of the light guide. The connector comprises a plurality of terminals including anode and cathode configured to be electrically connected to the light emitters. The terminals are arranged in an identical sequence in the first components. The two second components each comprise a base portion, a plurality of light emitters, and a connector. The base portion is arranged along an edge of the light guide. The light emitters are arranged on the base portion to face the edge of the light guide. The connector comprises a plurality of terminals including anode and cathode configured to be electrically connected to the light emitters. The terminals are arranged in an identical sequence in the second components.

Exemplary embodiments will be described in detail below with reference to the accompanying drawings, in which, for the sake of convenience, directions are defined as follows: X direction indicates the left direction in the front view of the display screen (the right direction in the back view); Y direction indicates the up direction; and Z direction indicates the normal direction of the display screen.

As illustrated in FIGS. 1 and 2 , a video display device 1 of an embodiment will be described by way of example as a television receiver. The video display device 1 comprises a base 3 and a relatively thin flat rectangular main body 2 . The main body 2 is supported on the base 3 via a leg 5 and an attachment portion 6 . The main body 2 comprises a housing 2 c on a front surface 2 a of which is provided a rectangular opening 2 e . The housing 2 c houses therein a display module 4 (a display unit 8 ) having a display screen 4 a that is exposed from the opening 2 e . The display module 4 may be, for example, a liquid crystal display (LCD) panel or an organic electroluminescent display (GELD) panel.

For example, the housing 2 c is formed of a combination of parts such as a front mask 2 d on the front surface 2 a side and a back cover 2 f on the side of a back surface 2 b . The attachment portion 6 protrudes from the back surface 2 b toward the back, and is supported by the leg 5 to be rotatable about the rotation axis C.

As illustrated in FIG. 3 , a plurality of circuit boards 7 ( 7 A to 7 D) are attached by fasteners such as screws (not illustrated) onto a back surface 8 a of the display unit 8 including the display module 4 . The circuit boards 7 are each fixed on a boss (not illustrated) protruding on the back surface 8 a . Thus, there is a space between the circuit boards 7 and the back surface 8 a.

The back surface 8 a of the display unit 8 corresponds to a back plate 8 b that is provided with two frames 9 A and a frame 9 B. The frames 9 A are spaced apart in the horizontal direction and extend in the vertical direction. The frame 9 B is a bridge between the vertical centers of the frames 9 A and extends in the horizontal direction. The frames 9 A and 9 B protrude toward the opposite of the display screen 4 a , i.e., on the back surface 8 a . The frames 9 A and 9 B are portions (reinforcement portions, frame portions) that structurally reinforce the display unit 8 . The frames 9 A and 9 B may be formed by partly bending the back plate 8 b by pressing or the like, or by adding other parts. The frames 9 A and 9 B may also be formed by partly bending the back plate 8 b and then adding other parts.

In the example of FIG. 3 , the frames 9 A and 9 B are connected in an H-shape. The frames 9 A and 9 B divide the back surface 8 a of the display unit 8 into areas A 1 to A 4 . In the back view (i.e., in the view of FIG. 3 ), the area A 1 is located on the right side of the right frame 9 A, the areas A 2 and A 3 are located below and above the frame 9 B, respectively, in the horizontal center, and the area A 4 is located on the left side of the left frame 9 A. In FIG. 3 , the circuit boards 7 A to 7 D are installed in the areas A 1 to A 4 , respectively. Incidentally, as illustrated in FIG. 4 , each of the circuit boards 7 may be covered with a shield case 22 .

The circuit board 7 A in the right area A 1 is provide with, for example, a tuner, a connector for external connection, and the like (all not illustrated). The circuit of the circuit board 7 A processes a signal received via the tuner, the connector, or the like, and outputs video data, audio data, and the like.

The circuit board 7 B in the lower horizontal center area A 2 is provided with a frame rate control (FRC) circuit, a timing control (TCON) circuit, and the like. In the circuit board 7 B, the FRC circuit is arranged above the TCON circuit. Although not illustrated, a gate drive circuit that drives the display module 4 is provided at a position along the lower edge of the display module 4 below the circuit board 7 B.

The circuit board 7 C in the upper horizontal center area A 3 is provided with a power source circuit and the like. The arrangement of the power source circuit in the horizontal center area achieves a shorter power supply cable (not illustrated) that is routed between the circuit board 7 C and the circuit boards 7 A, 7 B, and 7 D. Further, the arrangement of the circuit board 7 C on the upper side allows heat generated by the power source circuit to be discharged upward easier compared to the case where the circuit board 7 C is arranged on the lower side. This facilitates to suppress the influence of the heat on other parts (for example, the circuit boards 7 A, 7 B, and 7 D).

The circuit board 7 D in the left area A 4 is provide with a drive circuit that controls the light emission of a plurality of light emitters 10 such as, for example, light emitting diodes (LEDs) and the like (see FIG. 6 ). The circuit board 7 D is also provided with connectors 12 d . Flat cables 11 that may be, for example, flexible printed circuits (FPC) or flexible flat cables (FFCs) have connectors 12 c configured to be connected to the connectors 12 d , respectively. The use of the flat cables 11 as wiring between the light emitters 10 and the circuit board 7 D facilitates to reduce the manufacturing process and cost compared to the use of individually independent wirings, twisted wires, or the like.

Components 13 are arranged above and below the circuit board 7 D, respectively. To avoid interference between the components 13 and the flat cables 11 , the connectors 12 d are provided not to upper and lower edges 7 a and 7 b of the circuit board 7 D but to left and right edges 7 c and 7 d thereof.

As illustrated in FIG. 4 , in the embodiment, the housing 2 c comprises the front mask 2 d and the back cover 2 f . The housing 2 c houses therein the display unit 8 comprising the display module 4 and a backlight 14 . After the backlight 14 is assembled into a backlight unit, the backlight unit (the backlight 14 ) may be assembled with the display module 4 to form the display unit 8 . Parts are assembled with screws 21 .

The display module 4 comprises a base portion 4 b , a panel 4 c , a source board 4 d , a source chip-on-film (COF) 4 e , a gate COF 4 f , and the like.

The backlight 14 comprises the back plate 8 b , a reflective layer 14 a , a light guide 15 , a prism layer 14 b , a polarization layer 14 c , a frame 14 d , components 16 , and the like. All the back plate 8 b , the reflective layer 14 a , the light guide 15 , the prism layer 14 b , and the polarization layer 14 c have a flat rectangular shape in the front view, and are layered in the order as illustrated in FIG. 4 .

In the embodiment, among edges 15 a to 15 d of the light guide 15 , the components 16 each having the light emitters 10 (see FIG. 7 ) are located along the edges 15 c and 15 d facing each other on horizontally opposite sides such that they are spaced apart from the edges 15 c and 15 d , respectively. Among edges 4 g to 4 j of the display module 4 , the edges 15 c and 15 d extend along edges 4 i and 4 j facing each other on horizontally opposite sides, i.e., left and right sides (see FIG. 4 ). Accordingly, the components 16 also extend along the edges 4 i and 4 j of the display module 4 .

As illustrated in FIG. 6 , the light emitters 10 provided to each of the components 16 are arranged along a base portion 16 a of the component 16 . In other words, as can be seen from FIG. 5 , the light emitters 10 are arranged, for example, in a line along the edges 15 c and 15 d . The light emitters 10 are located on the base portion 16 a of the component 16 to face the edges 15 c and 15 d . Accordingly, the light emitted from the light emitters 10 enters the plate-like light guide 15 from the edges 15 c and 15 d thereof and is emitted from a front surface 15 e . The reflective layer 14 a is located on the side of a back surface 15 f . With this, the light emitted from the back surface 15 f is reflected on the reflective layer 14 a , returns into the light guide 15 , and is emitted from the front surface 15 e . The light emitted from the front surface 15 e passes though the prism layer 14 b and the polarization layer 14 c and illuminates the back surface of the display module 4 (the display screen 4 a ) as backlight. The frame 14 d is made of a material with relatively high rigidity (for example, metal material, etc.), and functions as the housing of the backlight 14 and the display unit 8 together with the back plate 8 b and the frames 9 A and 9 B.

As illustrated in FIGS. 4 and 5 , in the embodiment, the two components 16 are located along each of the edges 15 c and 15 d facing each other on horizontally opposite sides of the rectangular light guide 15 . Namely, there are provided a total of the four components 16 . As illustrated in FIG. 6 , the components 16 each comprise the base portion 16 a , the light emitters 10 , and a connector 12 a . The light emitters 10 and the connector 12 a are, for example, soldered onto a surface 16 b of the base portion 16 a that faces the edge 15 c or 15 d of the light guide 15 . The base portion 16 a is made of a material with relatively high thermal conductivity, such as, for example, aluminum alloy. On the base portion 16 a are layered an insulating layer and a conductive layer, which forms a conductor pattern (not illustrated). The conductor pattern forms a circuit 18 (see FIG. 7 ) in which terminals 17 p and 17 m of the connector 12 a are electrically connected to the light emitters 10 . The base portion 16 a is provided with a through hole 16 d for screwing at an end 16 c in the longitudinal direction.

The connector 12 a of the embodiment is located at the end 16 c of the base portion 16 a in the longitudinal direction. The connectors 12 a of the respective components 16 are arranged on both ends in the longitudinal direction of the edges 15 c and 15 d of the light guide 15 , along which the components 16 are arranged.

In the embodiment, at least components 16 A and 16 D located in diagonal positions in FIG. 5 have the same specifications, while components 16 B and 16 C have the same specifications. That is, in the embodiment, the video display device 1 is provided with the four components 16 of two specifications (types). Those with one of the specifications correspond to the first component, while those with the other specifications correspond to the second component. In this manner, according to the embodiment, the same components 16 are used at a plurality of positions. This reduces the number of the components 16 , and thereby reduces the manufacturing process of the components 16 , resulting in less manufacturing cost.

More specifically, with respect to the components 16 A and 16 D, the arrangement of the terminals 17 p and 17 m is the same in the connector 12 a (see FIG. 7 ), the arrangement of the light emitters 10 corresponding to the terminals 17 p and 17 m is the same in the base portion 16 a (see FIG. 7 ), and the position of the connector 12 a is the same relative to the base portion 16 a (see FIG. 5 ). With respect to the components 16 A and 16 D, also, the arrangement of the terminals 17 p and 17 m is the same in the connector 12 a , the arrangement of the light emitters 10 corresponding to the terminals 17 p and 17 m is the same in the base portion 16 a , and the position of the connector 12 a is the same relative to the base portion 16 a . By arranging the terminals 17 p and 17 m in the same manner in the plurality of components 16 , the flat cables 11 of the same specifications can be used, and the terminals can be arranged in the same sequence in the plurality of connectors 12 d of the circuit board 7 D.

FIG. 7 illustrates the arrangement of the terminals 17 p and 17 m of the connectors 12 a of the four components 16 A to 16 D arranged as illustrated in FIG. 5 . As illustrated in FIG. 7 , with respect to all the four components 16 A to 16 D, the anode terminals 17 p are located at the end sides in the longitudinal direction of the facing edges 15 c and 15 d in the connectors 12 a . More specifically, with respect to the components 16 A and 16 C, the anode terminals 17 p are located at the upper end sides of the edges 15 c and 15 d . With respect to the components 16 B and 16 D, the anode terminals 17 p are located at the lower end sides of the edges 15 c and 15 d . The cathode terminals 17 m are located on the opposite sides of the anode terminals 17 p . In the embodiment, the connectors 12 a of all the four components 16 each have, for example, the three anode terminals 17 p and the eight cathode terminals 17 m . The three anode terminals 17 p are electrically connected to one another. There are provided eight parallel wirings (conductor pattern) between the anode terminals 17 p and the respective cathode terminals 17 m . Each wiring is provided with the five light emitters 10 . That is, in the embodiment, the components 16 are each provided with the 40 light emitters 10 . The light emission (turning on/off) of the light emitters 10 is controlled with respect to each of the cathode terminals 17 m . Either one of the anode and the cathode corresponds to the first electrode and the other corresponds to the second electrode.

Since the components 16 A and 16 C have the same specifications (structure), the light emitters 10 corresponding to the terminals 17 p and 17 m are arranged in the same manner on the base portion 16 a . For example, in the case of the component 16 A, the light emitters 10 electrically connected to the cathode terminal 17 m with pin number 1 are arranged on the center side of the facing edge 15 c (i.e., in the vertical center of FIG. 5 ). The light emitters 10 corresponding to a larger pin number are arranged on the end side of the edge 15 c in the longitudinal direction (i.e., on the upper side of FIG. 5 ). In the case of the component 16 D also, the light emitters 10 electrically connected to the cathode terminal 17 m with pin number 1 are arranged on the center side of the facing edge 15 c (i.e., in the vertical center of FIG. 5 ). The light emitters 10 corresponding to a larger pin number are arranged on the end side of the edge 15 c in the longitudinal direction (i.e., on the lower side of FIG. 5 ).

In the embodiment, if the component 16 A is rotated 180° along the plane of FIG. 5 (i.e., the XY plane, the plane along the display screen 4 a and the back surface 8 a , the plane perpendicular to the surface of the base portion 16 a where the light emitters 10 are arranged and along the longitudinal direction of the base portion 16 a ), it matches the component 16 D. In other words, the components 16 A and 16 D are a pair of the components 16 that can be replaced with each other. The same applies to the components 16 B and 16 C. Namely, the components 16 B and 16 C are a pair of the components 16 that can be replaced with each other. It is effective to use the same components 16 in the state where they are rotated 180° with respect to each other along the XY plane at a plurality of positions if the components 16 cannot be used in the state where the front (front surface side) and back (back surface side) are reversed in the normal direction of the display screen 4 a , as, for example, if the components 16 are not symmetrical with respect to the XY plane. If the components 16 can be used in the state where the front (front surface side) and back (back surface side) are reversed in the normal direction of the display screen 4 a without any problem on the light emission of the light emitters 10 , connection between the flat cables 11 and the connectors 12 a , or the like, they can be used in different postures (the postures of FIG. 5 , the front and back may be reversed) at four positions illustrated in FIG. 5 .

FIG. 8 illustrates an example of the arrangement of the terminals (not illustrated) of the connectors 12 d provided to the circuit board 7 D. Regarding the two connectors 12 d located at the edge 7 c of the circuit board 7 D on the left side in FIG. 8 , the pin number increases from the bottom to the top. The terminals of upper one of the two connectors 12 d are connected to the terminals 17 p and 17 m of the connector 12 a on the lower left side in FIG. 7 via wiring (not illustrated) in the flat cable 11 . The terminals of the lower one of the connectors 12 d are connected to the terminals 17 p and 17 m of the connector 12 a on the lower right side in FIG. 7 via wiring in the flat cable 11 . As illustrated in FIG. 7 , in the lower left connector 12 a , the pin number increases from the bottom to the top. Meanwhile, in the lower right connector 12 a , the pin number increases from the top to the bottom. As illustrated in FIG. 3 , the flat cable 11 that is connected to the lower connector 12 d is routed in a U-shape such that the vertical order of wiring is reversed. Accordingly, it is possible to connect the terminals of the connector 12 d of the circuit board 7 D and the terminals 17 p and 17 m of the connector 12 a of the component 16 D where their arrangement sequence is vertically reversed. On the other hand, the flat cable 11 that is connected to the upper connector 12 d is routed in an S-shape or I-shape such that the vertical order of wiring is not reversed. Accordingly, it is possible to connect the terminals of the connector 12 d of the circuit board 7 D and the terminals 17 p and 17 m of the connector 12 a of the component 16 B where their arrangement sequence is vertically the same.

Regarding the two connectors 12 d located at the edge 7 d of the circuit board 7 D on the right side in FIG. 8 , the pin number increases from the top to the bottom. The terminals of upper one of the two connectors 12 d are connected to the terminals 17 p and 17 m of the connector 12 a on the upper left side in FIG. 7 via wiring (not illustrated) in the flat cable 11 . The terminals of the lower one of the connectors 12 d are connected to the terminals 17 p and 17 m of the connector 12 a on the upper right side in FIG. 7 via wiring in the flat cable 11 . As illustrated in FIG. 7 , in the upper left connector 12 a , the pin number increases from the bottom to the top. Meanwhile, in the upper right connector 12 a , the pin number increases from the top to the bottom. As illustrated in FIG. 3 , the flat cable 11 that is connected to the upper connector 12 d is routed in a U-shape such that the vertical order of wiring is reversed. Accordingly, it is possible to connect the terminals of the connector 12 d of the circuit board 7 D and the terminals 17 p and 17 m of the connector 12 a of the component 16 A where their arrangement sequence is vertically reversed. On the other hand, the flat cable 11 that is connected to the lower connector 12 d is routed in an S-shape or I-shape such that the vertical order of wiring is not reversed. Accordingly, it is possible to connect the terminals of the connector 12 d of the circuit board 7 D and the terminals 17 p and 17 m of the connector 12 a of the component 16 C where their arrangement sequence is vertically the same. As described above, according to the embodiment, the flat cables 11 are arranged as being bent in the in-plane direction along the back surface 8 a without twisted. With this, the connectors 12 a and 12 d with reverse terminal arrangement sequence can be connected by the flat cable 11 . Besides, according to the embodiment, the components 16 A and 16 D having the same specifications are located in diagonal positions. Meanwhile, the components 16 B and 16 C having the same specifications with the arrangement sequence of the terminals 17 p and 17 m being reversed from that of the components 16 A and 16 D are located in diagonal positions. Further, the flat cables 11 are arranged as being bent in the in-plane direction. Thus, the plurality of flat cables 11 can be arranged not to overlap each other.

As a modification illustrated in FIG. 9 , the components 16 may be arranged to face the upper and lower edges 15 a and 15 b of the light guide 15 . In addition, the number of the components 16 is not limited to four, there may be a different number of them. In the modification illustrated in FIG. 9 , the components 16 A and 16 D have the same specifications, while the components 16 B and 160 have the same specifications. This reduces the number of the components 16 , and thereby reduces the manufacturing process of the components 16 , resulting in less manufacturing cost.

As a modification illustrated in FIG. 10 , the connectors 12 d may be arranged at the upper edge 7 a of the circuit board 7 D, or may be arranged at the other edge 7 b , 7 c , or 7 d . Further, the connectors 12 d may be arranged separately at the plurality of edges 7 a to 7 d . In the example of FIG. 10 , terminal arrangement sequence is the same in all the connectors 12 d . In this case, for example, the leftmost connector 12 d in FIG. 10 is connected to the connector 12 a of the lower right component 16 D in FIG. 7 via the flat cable 11 . The second connector 12 d from the left in FIG. 10 is connected to the connector 12 a of the lower left component 16 B in FIG. 7 via the flat cable 11 . The second connector 12 d from the right in FIG. 10 is connected to the connector 12 a of the upper left component 16 A in FIG. 7 via the flat cable 11 . The rightmost connector 12 d in FIG. 10 is connected to the connector 12 a of the upper right component 16 C in FIG. 7 via the flat cable 11 .

Referring to a modification illustrated in FIG. 11 , the plurality of flat cables 11 overlap in the thickness direction with an insulator (shield) 19 as an interposer between them. If the flat cables 11 are overlapped in the thickness direction because of the location of the connectors 12 d , the layout of the components in the housing 2 c , or the like, the insulator 19 is interposed between them as illustrated in FIG. 11 . With this, it is possible to avoid the malfunction of the light emitters 10 due to signal leakage or the like.

While the above embodiment is described as being applied to the video display device as an electronic device provided with a display unit comprising a display module and a backlight unit, it may also be applied to other electronic devices such as a personal computer provided with the same display unit. Besides, regarding the video display device, the electronic device, the backlight unit, the housing, the display module, the light guide, the component, the light emitter, the connector, the circuit board, and the like, the specifications (structure, shape, size, length, width, thickness, height, number, arrangement, location, material, etc.) can be suitably modified.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.