LIGHT SOURCE SUBSTRATE, BACKLIGHT DEVICE, AND DISPLAY DEVICE

A light source substrate includes a substrate portion; a plurality of light sources mounted on the substrate portion in a row; a first terminal portion that is included in any of the plurality of light sources; a second terminal portion that is included in a light source, which is adjacent to the light source including the first terminal portion, of the plurality of light sources and that is fitted to the first terminal portion to be coupled to the first terminal portion; and a common pad that is disposed at a position at which the common pad overlaps the first terminal portion and the second terminal portion which fit each other on the substrate portion and that is connected to the first terminal portion and the second terminal portion which fit each other.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light source substrate, a backlight device, and a display device.

2. Description of the Related Art

In recent years, there has been a strong demand to increase the display area of a liquid crystal display device while maintaining the external size of the liquid crystal display device. In addition, to improve design, there has been a strong demand for picture-frame narrowing in which a picture-frame portion of a liquid crystal display device is reduced. One problem with picture-frame narrowing is generation of hot spots (luminance unevenness in which luminance is locally high in part of an area of a screen) which is the result of short distances, to the display area, from chip LEDs, which are mounted at an interval on a picture-frame portion. In a case where the distance from the chip LEDs to the display area is constant, when the chip LEDs are mounted at a narrower interval, it is possible to suppress generation of hot spots. Accordingly, to prevent generation of the hot spot while achieving picture-frame narrowing, it is necessary to mount the chip LEDs on the picture-frame portion at a narrow pitch, and, as a technique therefor, techniques described in Japanese Unexamined Patent Application Publication No. 2015-165525 and International Publication No. 2009/028612 below are known.

According to Japanese Unexamined Patent Application Publication No. 2015-165525, electronic components are connected by a wire that passes outside of an area between pads to which adjacent electronic components are respectively connected, and a good solder fillet is thereby formed on each terminal, such that it is possible to provide a flexible printed circuit board on which the electronic components are able to be mounted at a narrower pitch while sufficient bonding strength is secured. Further, International Publication No. 2009/028612 describes that a light emitting device in which an interval between adjacent chip LEDs is decreased and which is able to prevent short circuit is able to be provided by providing mounting bases, on which the chip LEDs are respectively mounted, on an insulating base material.

SUMMARY OF THE INVENTION

According to Japanese Unexamined Patent Application Publication No. 2015-165525 described above, the flexible printed circuit board on which chip LEDs to be connected to each other are mounted adjacently is provided with a land to which a terminal of one chip LED on a side of the other chip LED is connected and a land to which a terminal of the other chip LED on a side of the one chip LED is connected. The two lands are connected by a wire passing outside of an area that has an approximately strip shape formed by connecting end portions of the two lands in a width direction or end portions of the two lands in a thickness direction with a straight line. In this manner, even in a case where an interval between the two lands is narrow, when a terminal is soldered, it is possible to suppress flow of molten solder from one land to the other land along the wire, thus making it possible to secure sufficient bonding strength in each of the lands. It is described that an interval between two chip LEDs is thus able to be further narrowed, while maintaining sufficient bonding strength.

Further, it is described that, according to the light emitting device described in International Publication No. 2009/028612 above, by forming the mounting bases on a wiring substrate and mounting the chip LEDs thereon, generation of voids in a bonding section between a chip LED and a metal layer is suppressed and pitch reduction is enabled while short circuit between the chip LEDs is prevented. However, neither Japanese Unexamined Patent Application Publication No. 2015-165525 nor International Publication No. 2009/028612 refers to a technique by which, among chip LEDs that are mounted on a substrate and adjacent to each other, a terminal portion of one chip LED and a terminal portion of the other chip LED, which is adjacent to the one chip LED, on a side of the one chip LED are mounted on the same pad on the substrate while also achieving pitch reduction.

An aspect of the invention has been completed on the basis of such circumstances and aims to enable light sources to be mounted on a light source substrate at a narrow pitch and achieve picture-frame narrowing while suppressing luminance unevenness (generation of a hot spot).

(1) An embodiment of the invention is a light source substrate including: a substrate portion; a plurality of light sources mounted on the substrate portion in a row; a first terminal portion that is included in any of the plurality of light sources; a second terminal portion that is included in a light source, which is adjacent to the light source including the first terminal portion, of the plurality of light sources and that is fitted to the first terminal portion to be coupled to the first terminal portion; and a common pad that is disposed at a position at which the common pad overlaps the first terminal portion and the second terminal portion which fit each other on the substrate portion and that is connected to the first terminal portion and the second terminal portion which fit each other.

(2) Further, an embodiment of the invention is the light source substrate, in which the first terminal portion includes a protrusion that protrudes in a row direction of the light sources and the second terminal portion includes a recess that accepts the protrusion, in addition to a configuration of (1) described above.

(3) Further, an embodiment of the invention is the light source substrate, in which the protrusion has a shape that protrudes in the row direction of the light sources in plan view and the recess has a recessed shape that accepts the protrusion in plan view, in addition to a configuration of (2) described above.

(4) Further, an embodiment of the invention is the light source substrate, in which the protrusion has a shape including a portion a width of which is wider at a location further from the light source than at a location closer to the light source in plan view and the recess has a recessed shape that accepts the protrusion in plan view, in addition to the configuration of (2) described above.

(5) Further, an embodiment of the invention is the light source substrate, in which the first terminal portion includes a first protruding portion that projects to a side of the second terminal portion and a first angled portion that is bent from a tip end of a projection of the first protruding portion and the second terminal portion includes a second protruding portion that projects to a side of the first terminal portion and a second angled portion that is bent from a tip end of a projection of the second protruding portion, in addition to the configuration of (1) described above.

(6) Further, an embodiment of the invention is the light source substrate, in which each of the plurality of light sources includes the first terminal portion at one end portion in a row direction and includes the second terminal portion at the other end portion, in addition to a configuration of any one of (1) described above to (5) described above.

(7) Further, an embodiment of the invention is a backlight device including: the light source substrate according to any one of (1) described above to (6) described above; and a light guide plate that includes a light entering end surface on which light emitted from the light sources is incident and a light emitting plate surface from which the light is emitted.

(8) Further, an embodiment of the invention is a display device including: the backlight device according to (7) described above; and a display panel that displays an image by utilizing the light emitted from the backlight device.

According to an aspect of the present invention, it is possible to achieve picture-frame narrowing while suppressing occurrence of luminance unevenness.

DETAILED DESCRIPTION OF THE INVENTION

Embodiment 1 of the invention will be described with reference toFIGS. 1 to 10. In Embodiment 1, a backlight device12that includes an LED substrate (light source substrate)22and a liquid crystal display device (display device)10that uses the backlight device12are exemplified. Note that, an X-axis, a Y-axis, and a Z-axis are indicated at part of each drawing, and the direction of each axis is illustrated so as to correspond to the same direction in the respective figures. Further,FIG. 2is a reference of an up-down direction, and an upper side of the figure is set as a front side and a lower side of the figure is set as a rear side.

As illustrated in an exploded perspective view ofFIG. 1, the liquid crystal display device10includes a liquid crystal panel (display panel)11that displays an image and the backlight device12that illuminates the liquid crystal panel11with light, and the liquid crystal panel11and the backlight device12are integrally held by, for example, a bezel13that has a frame shape.

Next, the liquid crystal panel11and the backlight device12that constitute the liquid crystal display device10will be described in order. Of the liquid crystal panel11and the backlight device12, the liquid crystal panel11has a quadrangular shape which is laterally elongated in plan view, and includes a pair of glass substrates bonded in a state of a predetermined gap provided therebetween, and a liquid crystal layer including molecules of a liquid crystal, which is a substance whose optical characteristics change in accordance with application of an electric field, is sealed between the two glass substrates. On an inner surface side of one glass substrate (array substrate, active matrix substrate), switching elements (for example, TFTs) which are connected to source wires and gate wires that are orthogonal to each other and pixel electrodes each of which is disposed in a quadrangular area surrounded by the source wires and the gate wires and which are connected to the switching elements are arranged in a planar matrix, and, in addition, an alignment film and the like are provided. On an inner surface side of the other glass substrate (counter substrate, CF substrate), a color filter in which coloring portions of R (red), G (green), B (blue), and the like are arranged in a planar matrix of a predetermined array is provided, and, in addition, a light shielding layer (black matrix) which is disposed between the coloring portions and has a lattice shape, a counter electrode in a solid state facing the pixel electrodes and, an alignment film, and the like are provided. Note that, inFIG. 2, on a front surface of the liquid crystal panel11, an area overlapping an opening of the bezel13is an AA (active area) in which an image is able to be displayed. Further, a long-side direction of the liquid crystal panel11coincides with an X-axis direction, a short-side direction coincides with a Y-axis direction, and a thickness direction coincides with a Z-axis direction.

As illustrated inFIG. 1, the backlight device12includes at least the LED substrate (light source substrate)22that is constituted by a substrate portion20and chip LEDs (light sources)21mounted on the substrate portion20, a light guide plate23that guides light from the chip LEDs21to the liquid crystal panel11, and a reflective sheet24that is disposed on a rear side (side opposite to the liquid crystal panel11) of the light guide plate23. Further, the backlight device12includes a frame14in a frame shape that surrounds the light guide plate23, the LED substrate22, and the like, and a chassis15disposed on a rear side of the frame14. In the backlight device12in the present embodiment, the LED substrate22is disposed on one end portion (on a near side inFIG. 1) of a pair of end portions on the long sides of the backlight device12, and the respective chip LEDs21mounted on the substrate portion20of the LED substrate22are disposed unevenly close to one end portion on the long sides of the liquid crystal panel11. That is, the backlight device12according to the present embodiment is an edge light type (side light type) of a single-side light entering type in which light from the chip LEDs21enters the light guide plate23from a single side only. Next, each component of the backlight device12will be described in detail.

The light guide plate23is plate-shaped and is formed of a synthetic resin material (for example, acrylic resin such as PMMA, polycarbonate, or the like), a refractive index of which is sufficiently higher than that of air, and which is almost transparent (excellent in transparency). As illustrated inFIGS. 1 and 2, the light guide plate23has a quadrangular shape, a size of which is almost the same as that of the liquid crystal panel11in plan view, and which is elongated laterally, and a long-side direction and a short-side direction of a plate surface thereof coincide with the X-axis direction and the Y-axis direction, respectively. The light guide plate23has functions of introducing light (light emitted in the Y-axis direction) from light emitting surfaces21A of the chip LEDs21through a light entering end surface23A, which is a side surface facing the light emitting surfaces21A, changing the direction of light, which has entered the light entering end surface23A, toward the liquid crystal panel11side while transmitting the light inside, and emitting the light from a light emitting plate surface23B on a front side.

The reflective sheet24is disposed between the rear side of the light guide plate23, that is, a plate surface on a side opposite to the light emitting plate surface23B, and the chassis15so as to overlap the light guide plate23in plan view. A front surface of the reflective sheet24is white, a color having excellent light reflectivity, and, by reflecting light which has been transmitted in the light guide plate23and reached the surface on the rear side (side opposite to the light emitting plate surface23B) of the light guide plate23, the reflective sheet24changes the direction of light toward the front side, that is, the light emitting plate surface23B.

The chassis15is made of metal, resin, or the like and has a quadrangular shape which overlaps the frame14in plan view and which is elongated laterally. The LED substrate22and the reflective sheet24are fixed to the chassis15with double-sided tape or the like.

The frame14is made of metal, resin, or the like and has a frame shape, which is elongated laterally, so as to surround the liquid crystal panel11, the light guide plate23, the LED substrate22, and the like. The bezel13and the chassis15are fixed to the frame14with double-sided tape or the like.

Each of the chip LEDs21is a white LED that emits white light and is obtained by sealing a semiconductor element (blue LED chip) made from a compound semiconductor, such as, for example, InGaN within a package by using resin which contains a yellow phosphor, or the like. As illustrated inFIGS. 1 and 2, each chip LED21has an approximately parallelepiped shape, is arranged so that a bottom surface is in contact with the substrate portion20, and is a side light emitting type in which one surface of side surfaces adjacent to the bottom surface is a light emitting surface21A. Further, among the four side surfaces of the chip LED21, two parallel surfaces adjacent to the light emitting surface21A are provided with two terminal portions31in total (a first terminal portion31A and a second terminal portion31B) made of metal, which are electrically connected to the semiconductor element sealed inside, and the light emitting surface21A emits white light when a predetermined voltage is applied between the two terminal portions31.

The substrate portion20is a flexible printed circuit board (FPC) in which a pad32formed of a metal film (for example, a copper film) and a wiring pattern are appropriately formed on a film made of an insulating material, such as polyimide, which has flexibility. As illustrated inFIG. 1, the substrate portion20has a narrow elongated shape that extends in a long-side direction (X-axis direction) of the chassis15, and a front surface thereof is parallel to a plate surface of the chassis15and the plate surface of the light guide plate23. That is, the substrate portion20has an orientation in which a long-side direction (length direction) and a short-side direction (width direction) of the front surface coincide with the X-axis direction and the Y-axis direction, respectively, and, furthermore, a thickness direction orthogonal to the front surface coincides with the Z-axis direction. Accordingly, as illustrated inFIG. 2, the light emitting surface21A of the chip LED21of the side light emitting type mounted on the substrate portion20faces the light entering end surface23A of the light guide plate23. Further, an optical axis of each of the chip LEDs21, that is, a propagation direction of light whose light emission intensity is highest coincides approximately with a direction normal to the light emitting surface21A (direction normal to the light entering end surface23A in the Y-axis direction), and although light emission intensity decreases as the angle from the normal direction increases, light is diffused within a range demarcated by the light emitting surface21A and two one-dot chain lines extending from end portions of the light emitting surface21A inFIG. 3.

Further, as illustrated inFIG. 3, common pads33made of metal and connected to the terminal portions31A and31B of the chip LEDs21are provided on the front surface of the substrate portion20. Although details will be described later, the substrate portion20and the chip LEDs21are connected by applying solder paste onto a common pad33, thereafter mounting the chip LEDs21on the front surface of the substrate portion20so that a coupled terminal portion31E, which is formed of the terminal portions31A and31B, and the common pad33overlap, and thereafter performing a reflow process. Accordingly, the chip LEDs21are connected to the substrate portion20via solder, thereby forming the LED substrate22.

The two types of terminal portions31A and31B that are included in the chip LED21according to the present embodiment will be described in detail. When attention is paid to two chip LEDs21adjacent to each other mounted on the substrate portion20, and when the terminal portion31that is included in one chip LED21on a side of the other chip LED21is the first terminal portion31A and the terminal portion31that is included in the other chip LED21on a side of the one chip LED21is the second terminal portion31B, the shapes of the two terminal portions31A and31B are provided so as to fit each other as illustrated inFIG. 4. Specifically, the first terminal portion31A includes a protrusion31C that protrudes in a row direction of the chip LEDs21, and the second terminal portion31B has a shape including a recess31D that accepts the protrusion31C.

With such a configuration, as illustrated inFIGS. 5 and 6, when the two adjacent chip LEDs21are displaced in the row direction so as to be close to each other, the protrusion31C of the first terminal portion31A and the recess31D of the second terminal portion31B fit each other and are coupled, thereby forming the coupled terminal portion31E. Accordingly, the two chip LEDs21are also coupled, such that relative displacement is regulated between the adjacent chip LEDs21. Accordingly, occurrence of positional deviation between the adjacent chip LEDs21on the substrate portion20is suppressed.

Next, the common pad33provided on the front surface of the substrate portion20according to the present embodiment will be described with reference toFIGS. 7 and 8. As illustrated inFIG. 7, in the related art, when two chip LEDs21are mounted on the substrate portion20, pads32are provided so that each of the pads32corresponds to one terminal portion31on a one-to-one basis. In this manner, the chip LEDs21are mounted while occurrence of positional deviation is suppressed, but it is difficult to perform mounting at a pitch narrower than P1illustrated inFIG. 7.

On the other hand, with the configuration according to the present embodiment, as illustrated inFIG. 8, the first terminal portion31A and the second terminal portion31B that are included in the two adjacent chip LEDs21are fitted to form one coupled terminal portion31E, and the coupled terminal portion31E is soldered and connected to one common pad33which is disposed at a position of the substrate portion20at which the common pad33overlaps the coupled terminal portion31E.

Accordingly, the number of pads necessary for mounting two chip LEDs21adjacent to each other is able to be reduced by one from four in the case ofFIG. 7to three in the case ofFIG. 8. Accordingly, the distance (pitch) between the adjacent chip LEDs21is able to be further reduced from P1illustrated inFIG. 7to P2illustrated inFIG. 8.

Further, as illustrated inFIG. 5, each of the chip LEDs21according to the present embodiment includes the first terminal portion31A at one end portion in the row direction and the second terminal portion31B at the other end portion in the row direction. This makes it possible to couple the chip LEDs21in a row via coupled terminal portions31E as illustrated inFIG. 9.

Further, as illustrated inFIG. 3, by connecting the coupled terminal portion31E to the common pad33, it is possible to omit one pad in each space between the chip LEDs21, thus making it possible to reduce the distances between adjacent chip LEDs21by an amount corresponding to one pad. As a result, although the chip LEDs21are mounted at the pitch P1in the related art as illustrated inFIG. 10, according to the present embodiment, it is possible to mount the chip LEDs21at the narrower pitch P2.

As described above, the LED substrate22according to the present embodiment includes the substrate portion20, the chip LEDs21that are mounted on the substrate portion20in a row, the first terminal portion31A that is included in any of the chip LEDs21, the second terminal portion31B that is included in a chip LED21of the chip LEDs21, which is adjacent to the chip LED21including the first terminal portion31A, and that is fitted to the first terminal portion31A to thereby be coupled to the first terminal portion31A, and the common pad33that is disposed at a position at which the common pad33overlaps the first terminal portion31A and the second terminal portion31B which fit each other on the substrate portion20and that is connected to the first terminal portion31A and the second terminal portion31B which fit each other.

Accordingly, the first terminal portion31A included in one chip LED21and the second terminal portion31B included in the other chip LED21adjacent to the one chip LED21are fitted and the two terminal portions31A and31B are coupled, and the two chip LEDs21are also coupled accordingly. Subsequently, relative displacement is regulated between the adjacent chip LEDs21. Accordingly, occurrence of positional deviation of the adjacent chip LEDs21is suppressed on the substrate portion20. If positional deviation occurs, directions of the chip LEDs21are not stably maintained, and a direction of light (optical axis) to be emitted varies regarding each of the chip LEDs21, resulting in a deterioration in the uniformity of light emitted from the whole LED substrate22. However, such malfunctioning is able to be prevented in the present embodiment.

Further, relative displacement of the coupled first terminal portion31A and second terminal portion31B is regulated, and the first terminal portion31A and the second terminal portion31B form one coupled terminal portion31E that is coupled and are able to be collectively connected to one common pad33that is disposed at a position at which the common pad33overlaps the coupled terminal portion31E on the substrate portion20. As illustrated inFIG. 7, in the related art, when two chip LEDs21are mounted on the substrate portion20, the pads32are provided so that each of the pads32corresponds to one terminal portion31on a one-to-one basis. This is because, when one pad32corresponds to one terminal portion31, at a time of a reflow process, occurrence of positional deviation of the chip LEDs21is suppressed by a self-alignment effect.

However, when mounting the chip LEDs21at a narrower pitch is intended, it is not desirable to mount two terminal portions31on one pad32as they are. This is because, at the time of a reflow process, the two terminal portions31move around without restriction on molten solder on the one pad32and may interfere with each other, and it is therefore anticipated that positional deviation may occur between the adjacent chip LEDs21. Thus, as illustrated inFIG. 7, the number of pads32necessary for mounting two chip LEDs21on the substrate portion20is four in the related art, which is the same as the total number of the terminal portions31.

On the other hand, with the configuration according to the present embodiment, as illustrated inFIG. 8, the first terminal portion31A and the second terminal portion31B that are included in two adjacent chip LEDs21fit each other and form the coupled terminal portion31E. As a result, the coupled terminal portion31E acts as a single terminal and is therefore able to be soldered and connected to a single common pad33that is disposed at a position at which the common pad33overlaps the coupled terminal portion31E on the substrate portion20. That is, with the configuration according to the present embodiment, the total number of pads necessary for mounting two chip LEDs21on the substrate portion20is three (two pads32and one common pad33).

Accordingly, it is possible to reduce the number of pads necessary for mounting two chip LEDs21adjacent to each other by one from four in the case ofFIG. 7to three in the case ofFIG. 8. Accordingly, the distance (pitch) between the adjacent chip LEDs21is able to be further reduced from P1illustrated inFIG. 7to P2illustrated inFIG. 8, and thus mounting at a narrow pitch is enabled.

When the distance between the chip LEDs21is able to be reduced, it is possible to reduce the size of an area in the vicinity of the LED substrate22not reached by the light from the chip LED21, thus making it possible to make light emitted from the whole LED substrate22more uniform. As above, according to the present embodiment, it is possible to realize the LED substrate22in which the chip LEDs21are mounted at a narrow pitch and which is capable of more uniform light emission.

Further, the LED substrate22according to the present embodiment is provided with the first terminal portion31A including the protrusion31C that protrudes in the row direction of the chip LEDs21and the second terminal portion31B including the recess31D that accepts the protrusion31C.

Accordingly, in a case where the chip LED21including the first terminal portion31A and the chip LED21including the second terminal portion31B are coupled, when at least one of the two chip LEDs21on the substrate portion20is displaced in a direction of mutual approach in the row direction and the protrusion31C of the first terminal portion31A is fitted into the recess31D of the second terminal portion31B, the first terminal portion31A and the second terminal portion31B fit each other and the two terminal portions31A and31B and the two chip LEDs21are coupled. Accordingly, relative displacement of the adjacent chip LEDs21is regulated, and occurrence of positional deviation particularly in a direction perpendicular to the row direction on the substrate portion20is able to be suppressed, such that a positional relationship between the respective chip LEDs21is able to be stably maintained. As above, it is possible to realize the LED substrate22that is capable of more uniform light emission.

Further, in the LED substrate22according to the present embodiment, each of the chip LEDs21includes the first terminal portion31A at one end portion in the row direction and the second terminal portion31B at the other end portion.

Accordingly, as illustrated inFIGS. 3 and 9, when the chip LEDs21are mounted on the substrate portion20in a row, the terminal portion31A included in one chip LED21is fitted and coupled to the second terminal portion31B included in an adjacent chip LED21. Further, the first terminal portion31A included in the adjacent chip LED21on a side opposite to the second terminal portion31B is further fitted and coupled to the second terminal portion31B included in an adjacent chip LED21. By repeating this, it is possible to couple the chip LEDs21in a row via coupled terminals (coupled terminal portions31E). Accordingly, relative displacement of each of the chip LEDs21with respect to the chip LED21adjacent thereto is regulated by the coupled terminal portion31E, and occurrence of positional deviation on the substrate portion20is suppressed, such that it is possible to stably maintain the positional relationship between the respective chip LEDs21.

Further, as illustrated inFIG. 3, when the coupled terminal portion31E is connected to the common pad33, it is possible to omit one pad in each space between the chip LEDs21, such that each distance between adjacent chip LEDs21is able to be reduced by an amount corresponding to one pad and P2is the resultant pitch. Although the chip LEDs21are mounted at the pitch P1in the related art as illustrated inFIG. 10, with the configuration according to the present embodiment, it is possible to mount the chip LEDs21, which are to be mounted in a row, at the pitch P2which is narrower, while stably maintaining the positional relationship. Therefore, it is possible to realize the LED substrate22that emits more uniform light.

Further, the backlight device12according to the present embodiment includes the LED substrate22and the light guide plate23that includes the light entering end surface23A on which light emitted from the chip LEDs21is incident and the light emitting plate surface23B from which the incident light is emitted.

Accordingly, the light emitted by the light emitting surfaces21A of the chip LEDs21is incident on the light entering end surface23A of the light guide plate23, repeatedly reflected within the light guide plate23, and then emitted from the light emitting plate surface23B. InFIGS. 3 and 10, each area which is demarcated by the light emitting surface21A of the chip LED21and the two one-dot chain lines extending obliquely from two ends of the light emitting surface21A is an area to which emitted light reaches directly, and the other areas are areas to which no emitted light reaches directly. That is, inFIG. 10illustrating an embodiment according to the related art, when D1is a distance from the light emitting surface21A to a point at which the one-dot chain lines intersect in a normal direction, an area to which light from the light emitting surface21A does not reach at all corresponds to a position which is not apart from the light emitting surface21A by D1or more. When the size of areas of the light guide plate23to which no emitted light directly reaches increases, luminance unevenness of the light emitting plate surface23B is generated in the vicinity of the light emitting surfaces21A, such that it is necessary to move the AA from the light emitting surfaces21A to a position at which luminance unevenness is not generated. In this case, a picture-frame portion of the backlight device12is not able to be narrowed.

With the configuration according to the present embodiment, as illustrated inFIG. 3, the chip LEDs21are mounted on the LED substrate22at the pitch P2which is narrower than the pitch P1illustrated inFIG. 10, such that a distance D2at which the one-dot chain lines intersect is narrower than D1illustrated inFIG. 10. Accordingly, even in the vicinity of the light emitting surfaces21A, it is possible to reduce an area to which no emitted light reaches directly, such that occurrence of luminance unevenness of the light emitting plate surface23B in the vicinity of the light emitting surfaces21A is able to be suitably suppressed. As a result, even when the AA is close to the vicinity of the light emitting surfaces21A, luminance unevenness is less likely to be generated in the AA, and the picture-frame portion of the backlight device12is able to be further narrowed.

Accordingly, with such a configuration, even when a distance between the light emitting surfaces21A of the chip LEDs21and the AA in plan view is reduced, occurrence of luminance unevenness on the light emitting plate surface23B is suitably suppressed. It is thereby possible to narrow the picture-frame portion of the backlight device12while suppressing occurrence of luminance unevenness.

Further, the liquid crystal display device10according to the present embodiment includes the backlight device12and the liquid crystal panel (display panel)11that displays an image by utilizing light emitted from the backlight device12.

Accordingly, light emitted from the light emitting plate surface23B of the backlight device12illuminates a rear surface of the liquid crystal panel11, and the liquid crystal panel11is able to display an image in the display area AA in a visually recognizable state by utilizing the light. Here, since occurrence of luminance unevenness on the light emitting plate surface23B is suitably suppressed in the backlight device12, the backlight device12emits uniform light to the rear surface of the liquid crystal panel11, and the liquid crystal panel11is thereby able to display a high-quality image on the front surface thereof. In addition, since the picture-frame portion of the backlight device12is narrowed, it is also possible to achieve picture-frame narrowing of the liquid crystal display device10including the backlight device12.

Embodiment 2 of the invention will be described with reference toFIGS. 11 and 12. The present embodiment is an embodiment having a configuration which is different from that of Embodiment 1 in shapes of a first terminal portion131A and a second terminal portion131B. Specifically, a protrusion131C included in the first terminal portion131A has a shape that protrudes in a row direction of chip LEDs121in plan view, and a recess131D included in the second terminal portion131B has a recessed shape that accepts the protrusion131C in plan view. Note that, an element that has a configuration similar to that of Embodiment 1 described above will be given the same reference sign, and redundant description of a structure, an action, and an effect thereof will be omitted.

As illustrated inFIG. 12, one chip LED121that includes the first terminal portion131A and a different chip LED121that is adjacent thereto and includes the second terminal portion131B are able to be coupled when the different chip LED121is brought close to the one chip LED121so that the first terminal portion131A of the one chip LED121and the second terminal portion131B of the different chip LED121overlap.

In the present embodiment, as in a case of Embodiment 1, by displacing the two adjacent chip LEDs121in the row direction so as to come close to each other, it is possible to fit the two terminal portions131A and131B to each other, and, in addition, also when the two terminal portions131A and131B included in the two chip LEDs121are brought close so as to overlap, it is possible to fit the two terminal portions131A and131B to each other, such that it is possible to select a fitting method as appropriate in response to a situation at a time of mounting. Generally, when an electronic component is mounted on a surface of a substrate by using a chip mounter, the electronic component is brought close to a pad on the substrate in a direction perpendicular to the surface of the substrate and is mounted on the substrate in many cases. Thus, the present embodiment is advantageous particularly in such a case. Further, relative displacement of the adjacent chip LEDs121, in particular, occurrence of positional deviation in a direction perpendicular to the row direction is suppressed on the substrate portion20.

Embodiment 3 of the invention will be described with reference toFIGS. 13 to 15. The present embodiment is an embodiment having a configuration which is different from that of Embodiment 1 in a shape of each of a first terminal portion231A and a second terminal portion231B. Specifically, as illustrated inFIG. 13, a protrusion231C included in the first terminal portion231A has a shape that includes a portion a width of which is wider at a location further from the a chip LED221than at a location closer to the chip LED221in plan view.

Further, a recess231D included in the second terminal portion231B has a recessed shape that accepts the protrusion231C in plan view. Specifically, the recess231D of the second terminal portion231B includes two protruding portions, which extend in a row direction, at two ends in a width direction of the recess231D in plan view, and forms the recessed shape as a whole. An area between the two protruding portions of the recess231D has a portion a width of which is narrower at a location further from the chip LED221than at a location closer to the chip LED221. Note that, an element that includes a configuration similar to that of Embodiment 1 described above will be given the same reference sign, and redundant description of a structure, an action, and an effect thereof will be omitted.

As illustrated inFIG. 14, one chip LED221that includes the first terminal portion231A and a different chip LED221that is adjacent thereto and includes the second terminal portion231B are able to be coupled when the different chip LED221is brought close to the one chip LED221so that the first terminal portion231A of the one chip LED221and the second terminal portion231B of the different chip LED221overlap.

In this case, the protrusion231C according to the present embodiment has the portion the width of which is wider at a location further from the chip LED221than at a location closer to the chip LED221. Accordingly, when the first terminal portion231A and the second terminal portion231B fit each other, relative displacement in a direction perpendicular to the row direction on the substrate portion20is regulated, and, in addition, relative displacement in a direction parallel to the row direction, in particular, in a direction in which the two adjacent chip LEDs221move away from each other is regulated. Accordingly, in addition to the direction perpendicular to the row direction on the substrate portion20, occurrence of positional deviation in the direction parallel to the row direction is also able to be suppressed, such that it is possible to realize an LED substrate222that is capable of more uniform light emission (FIG. 15).

Embodiment 4 of the invention will be described with reference toFIGS. 16 to 18. The present embodiment is an embodiment having a configuration which is different from that of Embodiment 1 in shapes of a first terminal portion331A and a second terminal portion331B. Specifically, as illustrated inFIG. 16, the first terminal portion331A included in one chip LED321of two adjacent chip LEDs321includes a first protruding portion41A that projects to a side of the second terminal portion331B and a first angled portion42A that is bent from a tip end of the projection of the first protruding portion41A. Further, the second terminal portion331B included in the other chip LED321includes a second protruding portion41B that projects to a side of the first terminal portion331A and a second angled portion42B that is bent from a tip end of the projection of the second protruding portion41B. Note that, an element that includes a configuration similar to that of Embodiment 1 described above will be given the same reference sign, and redundant description of a structure, an action, and an effect thereof will be omitted.

As illustrated inFIG. 17, in one chip LED321that includes the first terminal portion331A and a different chip LED321that is adjacent thereto and includes the second terminal portion331B, the two terminal portions331A and331B are coupled when the different chip LED321is brought close to the one chip LED321so that the first terminal portion331A of the one chip LED321and the second terminal portion331B of the different chip LED321overlap, and the adjacent two chip LEDs321are also coupled.

Accordingly, relative displacement of the adjacent chip LEDs321on the substrate portion20, in particular, occurrence of positional deviation in a direction in which the chip LEDs321come close to each other and in a direction in which the chip LEDs321move away from each other is able to be suppressed, such that a positional relationship of the respective chip LEDs321is able to be stably maintained, thus making it possible to realize an LED substrate322that is capable of more uniform light emission.

OTHER EMBODIMENTS

The invention is not limited to the embodiments described based on the description above and the drawings, and, for example, the following embodiments are also included in the technical scope of the invention.

(1) Although a case where the liquid crystal panel having the quadrangular shape is used as the display device has been described in each of the above-described embodiments, a shape of the liquid crystal panel according to the invention is not limited to the quadrangular shape, and may be a circular shape, an elliptical shape, a polygonal shape, or other shapes. In any case, an LED substrate is disposed along part of an outer periphery of the liquid crystal panel.

(2) Although a case where the backlight of the edge light type is used as the backlight device has been described in each of the above-described embodiments, the invention may also be applied to a case where chip LEDs are mounted on a rear side of a liquid crystal panel at a narrow pitch in a direct backlight.

(3) Although a case where the chip LEDs of the side light emitting type are used has been exemplified in each of the above-described embodiments, the invention may also be applied to chip LEDs of a top light emitting type. In this case, a substrate portion on which the chip LEDs are mounted is disposed so as to be parallel to an XZ plane.

(4) Although a case where the flexible printed circuit board (FPC) is used as the substrate portion on which the chip LEDs are mounted has been exemplified in each of the above-described embodiments, the invention may also be applied to a case where a rigid printed circuit board is used as a substrate portion.

(5) Although a case where the LED substrate is disposed along the long side of the liquid crystal panel has been exemplified in each of the above-described embodiments, a configuration in which an LED substrate is disposed along a short side may be provided.