JP2013033619A - Light source module and liquid crystal display equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source module and liquid crystal display equipped with the same that can restrain luminance unevenness, even when a plurality of light source substrates with a plurality of light sources aligned are arrayed in series.SOLUTION: In order that LED chips 23a are arranged on each LED substrate 24a at a light source density in which N pieces of the LED chips 23a are arranged for a unit length L of the LED substrate 24a, an interval LM/N between center positions of LED element groups G when the LED element groups G collecting the LED chips 23a by M pieces are equally arranged on the LED substrate 24a is to be nearer to an interval between the LED chips 23a, 23a as between the LED substrates 24a, 24a, than an interval L/N between the LED chips 23a, 23a when N pieces of LED chips 23a are equally arranged on the LED substrate 24a at the above light source density.

Description

  The present invention relates to a light source module and a liquid crystal display device including the light source module. Specifically, the optical device includes an optical member and a plurality of light sources arranged along the optical member, and the optical member from the light source. The present invention relates to a light source module that emits light incident on the optical member while being guided through the surface of the optical member, and a liquid crystal display device including the light source module.

  Liquid crystal display devices are used in various fields because they can be thin and lightweight. In a liquid crystal display device such as a liquid crystal television, a backlight including a light guide plate that emits light from a light source in a planar shape by the light guide plate is often used. Further, an LED (Light Emitting Diode) is used as a light source of the backlight.

  The arrangement of the light source of the backlight includes a direct type and a side edge type (also referred to as a side light type). A general direct type is a system in which LEDs are arranged in a matrix under a liquid crystal panel to uniformly irradiate the liquid crystal panel. In addition, the direct type includes a method in which light emitted from the LED is spread using a LED and a diffusion lens (a lens that diffuses light) to uniformly irradiate the liquid crystal panel.

  In such a backlight, various forms of LED light sources can be used.

  Specifically, for example, the planar illumination device disclosed in Patent Document 1 is a linear light source device in which LED chips 102 are linearly arranged on a substrate 101 as shown in FIGS. 100 is an edge light type backlight that emits light from the end of the light guide plate 103.

  When the linear light source device 100 is used, there is a merit that the complexity of wiring for supplying power to the LED chip 102 can be reduced as compared with the method of arranging the LED chips 102 individually. However, particularly in a large liquid crystal display device, since the light guide plate 103 is large, when the single linear light source device 100 is arranged according to the size of the light guide plate 103, the size of the linear light source device 100 is large. As a result, the manufacturing cost increases, and there is a problem that the assembling property is reduced, for example, a large assembling device is required when the linear light source device 100 is assembled to the liquid crystal display device. Further, in such a large linear light source device 100, there is a problem of thermal expansion due to heat generation of the LED chip 102. For example, there is a problem that the substrate 101 is likely to be distorted and warped due to heat generation of the LED chip 102. .

JP 2010-15709 A (published January 21, 2010) JP 2000-91646 A (published July 19, 2000)

  As a method for solving the above problem, for example, a method in which a plurality of small linear light sources are arranged in series instead of a large linear light source can be considered. When a plurality of small linear light sources are used, the cost can be reduced and the assemblability can be improved as compared with the case where a large linear light source is used. In addition, since the influence of strain and warpage is dispersed for each small substrate in terms of thermal expansion, it is possible to prevent large strain and warpage from occurring as a whole.

  However, the above method has the following problems.

  First, in the linear light source, in order to arrange the LED chips in series on the substrate so as to reduce the luminance unevenness, it is desirable to arrange them so that the intervals between the LED chips are equal. That is, the luminance is uneven because the luminance is high at a location where the density of the LED chip is high and the luminance is low at a location where the density of the LED chip is low. In addition, when the regularity such as the LED arrangement interval is suddenly changed, the luminance changes abruptly, resulting in luminance unevenness. Therefore, the LED chips are arranged so that the intervals are uniform. Thereby, since the density with respect to the whole board | substrate in an LED chip is disperse | distributed uniformly, said brightness | luminance unevenness can be reduced.

  However, since it is necessary to form a sealing resin, a dam structure that blocks the sealing resin, and a peripheral structure such as wiring around the LED chip, the LED chip cannot be disposed up to the end of the substrate. For this reason, the LED chip needs to be arranged at a distance from the end to such an extent that the above peripheral structure can be formed. As a result, the LED element cannot be arranged at the end of the substrate of the linear light source, and in the method of arranging a plurality of small linear light sources in series, the dark part where the LED element cannot be arranged at the joint of the linear light source Thus, there is a problem that uneven brightness occurs.

  In addition, since the substrates of the linear light source expand to some extent due to the heat generated by the LED chips, it is desirable that the substrates are arranged so that the substrates do not collide when thermally expanded. However, in that case, the dark area where the LED elements are not disposed further increases, and the luminance unevenness is further increased.

  In view of this problem, Patent Document 2 discloses a method of increasing the LED density at the end of the LED substrate 201 as shown in FIG. When this method is applied to a composite linear light source in which a plurality of small linear light sources are arranged in series, the brightness of the LED element high-density part at the end of the LED substrate 201 and the part where the LED element at the joint of the board is not arranged is sufficient. It is effective only when light is emitted to the outside in a mixed and uniform state. If the light is emitted to the outside without mixing the brightness between the above parts, the bright part of the LED element high-density part appears adjacent to the dark part of the LED seam, and the brightness unevenness increases. . In order to solve the above problem, generally, it is necessary to diffuse the emitted light of the LED elements and sufficiently mix the emitted lights of the adjacent LED elements. For this purpose, a mixed space of the emitted light in the light source device. There is a problem that the light source device is increased in size. In a liquid crystal display device, since the thickness and the width of the frame are generally limited, it is particularly difficult to provide the above space, and the above method has a problem that it is difficult to eliminate luminance unevenness. doing.

  The present invention has been made in view of the above-described conventional problems, and the object thereof is to obtain luminance even when a plurality of light source substrates in which a plurality of light sources are arranged side by side are arranged in series. It is an object of the present invention to provide a light source module capable of suppressing unevenness and a liquid crystal display device including the light source module.

In order to solve the above problems, a light source module of the present invention includes an optical member and a plurality of light sources disposed along the optical member, and light incident on the optical member from the light source is the optical member. In the light source module that guides the inside of the light source and emits light from the surface of the optical member, a plurality of light source substrates in which the plurality of light sources are arranged are arranged in series with each other, and each of the light source substrates A light source group in which a plurality of light sources are collected and arranged in close proximity is formed at the end of the light source, and the light sources are arranged on the light source substrate at a light source density at which N light sources are arranged per unit length L of the light source substrate. As described above, when the light source group, in which M light sources are collected, is arranged evenly on the light source substrate, the distance LM / N between the center positions of the light source groups is determined by the N light sources at the light source density. Between light sources when arranged evenly Than L / N, it is characterized in that has a value close to the interval of the light source between the light source substrate.

  According to the above invention, a plurality of light source substrates on which a plurality of light sources are arranged side by side are arranged in series. In such a case, at each end of the light source substrate, the light source cannot be disposed because it is necessary to form a peripheral structure such as a wiring, and as a result, it becomes a dark part and luminance unevenness occurs. Has a problem.

  Therefore, in the present invention, a light source group in which a plurality of light sources are gathered and arranged close to each other is formed at the end of each light source substrate, and the light source density at which N light sources are arranged per unit length L of the light source substrate. The distance LM / N between the center positions of the light source groups when the light source group in which M light sources are collected in a uniform manner is arranged on the light source substrate so that the light sources are arranged on the light source substrate is N pieces. It is a value closer to the interval between the light sources between the light source substrates than the interval L / N between the light sources when the light sources are evenly arranged on the light source substrate with the light source density.

  That is, even in a structure in which a plurality of light source substrates are arranged, discontinuity of the light source arrangement between the light source substrates can be reduced by arranging the light source groups evenly rather than simply arranging the light sources equally. And uneven brightness can be improved.

  Therefore, it is possible to provide a light source module that can suppress the occurrence of uneven brightness even when a plurality of light source substrates in which a plurality of light sources are arranged side by side are arranged in series.

  In the light source module of the present invention, the distance between the light source groups at the end of each light source substrate can be made uniform.

  Thereby, according to the space | interval of the light source group between light source substrates, the light source group in a light source substrate can be arrange | positioned at equal intervals. As a result, it is possible to suppress the occurrence of luminance unevenness due to the non-continuous change of the light source substrate and the light source array at the end of the light source substrate.

  In the light source module of the present invention, the density of the light sources in each light source group at the end of each light source substrate can be set to increase stepwise from the center side to the end of the light source substrate. It is.

  As a result, a state in which a plurality of light sources in the vicinity of the edge of the light source substrate are collected and arranged for each closely arranged light source group is continuously changed from a state in which the light sources in the center of the light source substrate are individually arranged for each one. be able to.

  Therefore, in the light source module of the present invention, the plurality of light sources are arranged in series in the center of each light source substrate, and the intervals between the light sources can be made uniform.

  Thereby, uneven brightness due to the arrangement of the light source for each light source group can be prevented. Further, since the arrangement state gradually changes to the light source arrangement state for each light source group at the end portion of the light source substrate, luminance unevenness does not occur during the change of the arrangement state.

  In the light source module of the present invention, in the central portion of each light source substrate, the plurality of light sources are arranged in series in a row, and the intervals between the light sources are uniform with each other. it can.

  That is, the central portion of the light source substrate is not affected by luminance unevenness due to a discontinuous change between the light source substrates. For this reason, in the central portion of each light source substrate, a plurality of light sources are arranged in series in a line, and the intervals between the light sources are made uniform so that complex brightness control is performed. Even if it is not, the occurrence of uneven brightness can be suppressed.

  In the light source module of the present invention, the optical member has a flat plate shape, and is provided on the lower side of the light guide plate that emits light from the upper surface while guiding incident light by totally reflecting the light inside. And a light coupling member that couples light so that light is incident on the light guide plate from an incident portion on a lower surface of the light guide plate, and the light source is formed from the lower side of the light coupling member. It is preferable that the coupling member is disposed so as to emit incident light.

  Thereby, the light emitted from the light source below the light guide plate enters the light guide plate via the optical coupling member, and a part of the light propagates to the end of the light guide plate while totally reflecting the inside of the light guide plate. At the same time, the total reflection condition is broken by the optical path conversion element as appropriate, and the light is emitted from the upper surface of the light guide plate.

  As a result, unlike the conventional side edge type light guide plate, since it is a backlight directly under the light guide plate, a light source and a light guide plate for avoiding thermal expansion required in the side edge type light guide plate, Thus, the coupling efficiency from the light source to the light guide plate can be increased, and the light utilization efficiency can be improved.

  Further, in the present invention, since the light coupling member separate from the light guide plate is provided so that light is incident from the incident portion on the lower surface of the flat light guide plate, the incident light is totally reflected inside the light guide plate. Light is guided. As a result, it is not necessary to process the light guide plate, the coupling efficiency from the light source to the light guide plate can be increased, the light utilization efficiency can be improved, and the manufacturing cost is also reduced.

  In order to solve the above-described problems, a liquid crystal display device according to the present invention includes the light source module described above as a backlight.

  According to the above invention, the liquid crystal display device including the light source module capable of suppressing the occurrence of luminance unevenness even when a plurality of light source substrates in which a plurality of light sources are arranged side by side are arranged in series with each other. Can be provided.

  In the light source module of the present invention, as described above, a plurality of light source substrates in which a plurality of light sources are arranged side by side are arranged in series with each other, and a plurality of light sources are arranged at the end of each light source substrate. A group of light sources that are gathered and arranged in close proximity is formed, and M light sources are collected one by one so that the light sources are arranged on the light source substrate at a light source density at which N light sources are arranged per unit length L of the light source substrate. The distance LM / N between the center positions of the light source groups when the light source groups are evenly arranged on the light source substrate is the distance between the light sources when N light sources are evenly arranged on the light source substrate at the light source density. It is a value closer to the interval of the light sources between the light source substrates than L / N.

  As described above, the liquid crystal display device of the present invention includes the light source module described above as a backlight.

  Therefore, even when a plurality of light source substrates in which a plurality of light sources are arranged side by side are arranged in series with each other, a light source module capable of suppressing the occurrence of luminance unevenness and a liquid crystal display device including the light source module There is an effect of providing.

(A) shows one Embodiment of the light source module in this invention, Comprising: It is a top view which shows the structure of the LED chip arranged on the LED board with which the light source module was equipped, (b) It is a figure which shows the luminance distribution of the X-axis direction by LED chip arrangement | sequence. It is a disassembled perspective view which shows the structure of the liquid crystal display device provided with the said light source module. (A) is sectional drawing which shows the whole structure of the said liquid crystal display device, (b) is sectional drawing which shows the structure of the light source unit in the liquid crystal display device shown to (a). It is a perspective view which shows the structure of the light source module in the said liquid crystal display device. It is a disassembled perspective view which shows the structure of the light source unit in the said light source module. It is a top view which shows the structure of the LED board in the said light source unit. (A) is sectional drawing which shows the optical path when the light radiate | emitted from the LED chip injects into a light-guide plate via the optical coupling member which has a paraboloid, (b) is principal part sectional drawing which shows the LED chip vicinity. It is. (A) is sectional drawing which shows the optical path when the light radiate | emitted from the LED chip injects into a light-guide plate via the optical coupling member which has an elliptical surface, (b) is principal part sectional drawing which shows LED chip vicinity. is there. It is a perspective view which shows the structure of the light source module which removed the said light-guide plate. It is sectional drawing cut | disconnected by the cut surface S in FIG. It is sectional drawing which expands and shows the principal part structure by the side of A of FIG. It is a top view which shows the structure of the LED board in a light source unit. (A) is a top view which shows the structure of the comparative example of the LED chip arranged in the LED board, (b) is a figure which shows the luminance distribution of the X-axis direction by the LED chip arrangement | sequence of the said comparative example. (A) is a top view which shows the structure of the other comparative example in the LED chip arranged on the LED board, (b) is a figure which shows the luminance distribution of the X-axis direction by the LED chip arrangement | sequence of the said other comparative example. is there. (A) is a principal part top view which shows the structure of the modification in the LED chip arranged in the LED board, (b) is a top view which shows the structure of the modification in the LED chip arranged in the LED board. (A) is a front view which shows the structure of a liquid crystal display device, (b) is the side view. FIG. 5 is a cross-sectional view showing a configuration of a light source unit according to another embodiment of the present invention and a liquid crystal display device including the light source module, the LED unit including two rows of LED chips. It is sectional drawing which shows a light path when it has a light source unit in an edge part, and the light radiate | emitted from two LED chips injects into a light-guide plate through the optical coupling member which has a paraboloid or an elliptical surface. It is principal part sectional drawing which shows the structure of the edge part of the said liquid crystal display device. (A) (b) is sectional drawing which shows the optical coupling member and light source which are located below the light-guide plate holding surface of a chassis. (A) shows further another embodiment of the light source module in this invention, and the liquid crystal display device provided with the light source module, Comprising: It is a disassembled perspective view which shows the structure of a liquid crystal display device, (b). It is sectional drawing which shows the structure of the principal part of the said liquid crystal display device. It is sectional drawing which shows an optical path when the light radiate | emitted from two LED chips injects into a light-guide plate through the optical coupling member which has a paraboloid or an elliptical surface. (A) is sectional drawing which shows the structure of a liquid crystal display device, (b) is a graph which shows the luminance distribution of a light-guide plate. FIG. 5 is a side view showing still another embodiment of the light source module according to the present invention and showing an edge light type backlight. (A) shows the structure of the conventional backlight, Comprising: It is a perspective view which shows the structure of a light source unit, (b) is the sectional drawing. (A) is a front view which shows the structure of the other conventional backlight, Comprising: The structure of the backlight which raised the density in the LED chip of the edge part side of an LED board is shown.

[Embodiment 1]
One embodiment of the present invention is described below with reference to FIGS.

(Overall configuration of liquid crystal display device)
A configuration of a liquid crystal display device including the light source module of the present embodiment will be described with reference to FIG. FIG. 2 is an exploded perspective view showing the configuration of the liquid crystal display device of the present embodiment.

  As shown in FIG. 2, the liquid crystal display device 1 of the present embodiment includes a backlight 10 as a light source module, a diffusion plate 2A, a prism sheet 3, a diffusion sheet 2B, a liquid crystal panel 4, and a bezel 5 stacked in this order. Has been placed. In the liquid crystal display device 1, the light emitted from the backlight 10 passes through the diffusion plate 2 </ b> A, the prism sheet 3, and the diffusion sheet 2 </ b> B and enters the liquid crystal panel 4. A desired image is displayed by partially changing the light transmittance in the liquid crystal panel 4. The liquid crystal panel 4 has a rectangular flat plate shape, and the diffusion plate 2A, the prism sheet 3 and the diffusion sheet 2B have substantially the same shape as the liquid crystal panel 4. Here, the direction parallel to the long side of the liquid crystal panel 4 is defined as the X direction, the direction parallel to the short side of the liquid crystal panel 4 is defined as the Y direction, and the direction perpendicular to both the X direction and the Y direction is defined as the Z direction. To do. The X direction is also referred to as the longitudinal direction. The Z direction can also be said to be the normal direction of the liquid crystal panel 4.

(Configuration of light source module)
As shown in FIG. 2, the backlight 10 as the light source module is similar to the light source unit 20, the chassis 11 having a single opening 11 a, and the chassis 11 in order from the bottom, that is, from the far side from the liquid crystal panel 4. It is composed of a reflection sheet 12 having a single opening 12a and a light guide plate 13 as an optical member. The chassis 11 is made of, for example, a material such as iron, and increases the strength of the backlight 10. The chassis 11 is formed in a rectangular shape that is substantially the same size as the liquid crystal panel 4.

  The light source unit 20 includes a light source holder 21 having a recess 21a. The recess 21a is a long or strip-like groove extending in the X direction. The light source holder 21 is disposed on the end side along the long side direction of the liquid crystal panel 4.

  The reflection sheet 12 is provided to reflect the light leaking from the light guide plate 13 and return it to the light guide plate 13. The reflection sheet 12 is divided into two parts at a portion where an optical coupling member 30 as an optical member, which will be described later, in the light source unit 20 contacts the light guide plate 13, and a single opening 12 a is formed between the two divided reflection sheets. Is formed. That is, on the lower surface of the light guide plate 13 on the light source unit 20 side, there are a region in contact with the optical coupling member 30 and a region in which the reflection sheet 12 is provided. Then, the light enters the light guide plate 13 through a region of the light guide plate 13 that contacts the optical coupling member 30.

  The light guide plate 13 is for guiding incident light to the liquid crystal panel 4 side, and has a flat plate shape.

  The light source module of the present invention only needs to include at least the light source unit 20 and the light guide plate 13.

(Configuration of light source unit)
Next, the configuration of the light source unit 20 will be described with reference to FIGS. 3 (a) and 3 (b), FIG. 4 and FIG. FIG. 3A is a cross-sectional view showing the overall configuration of the liquid crystal display device 1, and FIG. 3B is a cross-sectional view showing the configuration of the light source unit in the liquid crystal display device 1. FIG. 4 is a perspective view showing the configuration of the backlight in the liquid crystal display device 1. FIG. 5 is an exploded perspective view showing the configuration of the light source unit in the backlight. FIG. 6 is a plan view showing the configuration of the LED substrate in the light source unit.

  As shown in FIGS. 3A and 3B, the light source unit 20 includes an LED substrate 24a as a light source substrate on which an LED (Light Emitting Diode) chip as a light source is mounted, and a long shape. The optical coupling member 30 and the heat sink 22 are provided. The light coupling member 30 is an optical element for coupling light emitted from the LED chip and causing the light to enter the light guide plate 13 at a predetermined angle. Moreover, the LED board 24a and the optical coupling member 30 are mounted on the heat sink 22 as a plate-like member. Further, the light guide plate 13, the optical coupling member 30, the LED substrate 24a, and the heat sink 22 are arranged in this order. Since the semiconductor LED chip has a very fine size, the description for preventing the complexity of the drawings is omitted in FIGS.

  As shown in FIG. 4, the optical coupling member 30 is made of a translucent member having a bifurcated cross section in the X direction. And one side of this forked shape is arrange | positioned on LED board 24a. Moreover, the optical coupling member 30 has a top flat surface on the opposite side to the LED substrate 24a, and the light guide plate 13 is fixed to the top flat surface.

  The light emitted from the LED chip on the LED substrate 24 a enters from one of the bifurcated light incident surfaces of the optical coupling member 30, propagates through the optical coupling member 30, and is a top portion that is a fixed portion with the light guide plate 13. It is optically coupled to the light guide plate 13 on a flat surface. That is, the light enters the light guide plate 13. The light incident on the light guide plate 13 propagates in the Y direction while being totally reflected inside the light guide plate 13, and a part of the light is transmitted by a light scatterer as a light extraction means formed on the back surface of the light guide plate 13. The total reflection condition is broken, and the light is emitted from the surface of the unit light guide plate 13 to the arrow La that is above the Z direction. The light scatterer is a minute pattern formed on the back surface of the light guide plate 13 by printing or the like. Thus, since the light source unit 20 can emit light from the LED chip from almost the entire surface of the light guide plate 13, it can be used as a surface light emitting device. The detailed behavior of light from the LED chip to the light guide plate 13 in the light source unit 20 will be described later.

  In this embodiment, an LED chip is used as a light source. However, since a semiconductor chip-shaped LED is smaller in size and can be arranged in a narrow area, even when an inexpensive low-power LED chip is used. This is because it is preferable in that a large number of LEDs are arranged at close intervals to improve illuminance and to be used as a light source for a highly functional backlight. However, the present invention is not limited to this. For example, an LED housed in a package may be used, and an organic EL light emitting element or an inorganic EL light emitting element may be used.

As shown in FIG. 5, a dam 26a made of a white resin is formed on the surface of the LED substrate 24a. As shown in FIG. 6, the dam 26 a is formed long in the width direction (longitudinal direction) of the liquid crystal display device 1. Moreover, the dam 26a is formed in the recessed shape (refer FIG. 11 mentioned later). In the dam 26a, as shown in FIG. 6, the LED chips 23a are arranged in a row at intervals of, for example, several mm in the longitudinal direction of the dam 26a. An alignment mark 27a for adjusting the position with the optical coupling member 30 is provided on the outer periphery of the dam 26a. The alignment mark 27a is prepared in advance on the LED substrate 24a in order to define the mounting position of the LED chip 23a. The LED board 24a is a so-called printed wiring board, and is made of a material such as alumina, ceramic, or glass epoxy resin. The thickness of the LED substrate 24a is 2 mm, for example.

  Further, although not shown in FIG. 6, the dam 26a is filled with a transparent resin for sealing the plurality of LED chips 23a. And this transparent resin contains the fluorescent substance. The same type of phosphor is used for each LED chip 23a.

  Also, boss holes 28a and 28a are formed in the LED substrate 24a. The boss holes 28a and 28a are holes for inserting bosses 35a and 35a described later (see FIG. 9 described later).

  As shown in FIGS. 4 and 5, the optical coupling member 30 has a substantially U-shaped cross section perpendicular to the X direction, that is, a tunnel shape or an arch shape, and is a rod-like body that is long in the X direction. And it is provided between the light guide plate 13 and the LED chip 23a.

  As a result, the liquid crystal display device 1 of the present embodiment includes a liquid crystal panel 4, a light guide plate 13 that irradiates light to the liquid crystal panel 4, an optical coupling member 30 as an optical member that couples light to the light guide plate 13, The light coupling member 30 includes an LED chip 23a that emits incident light, and the liquid crystal panel 4, the light guide plate 13, the light coupling member 30, and the LED chip 23a are arranged in this order. The backlight 10 in the liquid crystal display device 1 is a backlight 10 directly under the light source in which the LED chip 23 a is provided below the light guide plate 13. The LED chips 23 a are arranged so that the optical axis direction of the emitted light, that is, the direction with the highest luminance in the incident light is orthogonal to the flat light guide plate 13.

  As shown in FIGS. 3A and 3B, the light source unit 20 is provided as a protruding portion at the end on the back side of the liquid crystal display device 1. The light coupling member 30 and the LED chip 23a are stored inside the light source unit 20. Further, the light source unit 20 is formed in a strip shape in the longitudinal direction (X direction) of the liquid crystal display device 1, and the optical coupling member 30 housed therein is also formed in a strip shape in the X direction. That is, it can be said that the “projection” is composed of the light coupling member 30, the LED chip 23 a, the cover thereof, and the like among the members constituting the light source unit 20.

  In the present embodiment, the light source unit 20 that is the protruding portion is formed in a rectangular cross section protruding from the flat surface of the chassis 11, but is not limited to this, and the cross section is semicircular or semielliptical It may be a polygon other than a quadrangle such as a triangle. In other words, the protruding portion is not intended only for a configuration having a convex shape with a square cross section, and various shapes and sizes are allowed as long as it has a function capable of storing an optical coupling member or a light source inside. The

  Moreover, in this Embodiment, the liquid crystal display device 1 raises the optical coupling efficiency from the LED chip 23a as a light source to the light-guide plate 13, without accompanying the technical idea of processing of a light-guide plate, and improves light utilization efficiency. obtain. Hereinafter, the detailed structure and optical path of the optical coupling member 30 will be described.

  As described above, the optical coupling member 30 is formed of a strip-like body having a substantially U-shaped cross section, that is, a rod-like body, provided between the light guide plate 13 and the LED chip 23a. The material of the optical coupling member 30 is made of the same resin as that of the light guide plate 13. Since the refractive index can be made the same if they are the same material, the light is smoothly incident on the light guide plate 13 from the optical coupling member 30. The refractive index of the light guide plate 13 may be slightly higher than the refractive index of the optical coupling member 30. Further, the material is not limited to resin, and a material such as glass may be used.

Specifically, as shown in FIG. 7A, the surface of the optical coupling member 30 on the light guide plate 13 side has a top flat surface 31 as an incident portion that contacts the flat light guide plate 13 and curved surfaces 32 a and 32 b. It is made up of. The curved surfaces 32a and 32b are formed as reflecting surfaces that extend away from the light guide plate 13 from the top flat surface 31 to both ends.

  The curved surfaces 32a and 32b can be, for example, a cross-sectional parabola shown in FIG. That is, the curved surfaces 32a and 32b form a parabola in the cross-sectional shape of the optical coupling member 30 perpendicular to the longitudinal direction (X direction) of the liquid crystal panel 4. However, the shape is not necessarily limited thereto, and may be a curved shape such as an elliptical cross section or a bow shape, or a flat surface inclined obliquely from the top flat surface 31 as long as it can effectively couple light to the light guide plate. Absent. Thereby, the optical coupling member 30 functions to propagate the light emitted from the light source while being bent inside the optical coupling member and to make the light incident on the flat light guide plate 13 obliquely. For this reason, most of the light from the light source can be coupled to the light guide plate 13.

  The surface of the optical coupling member 30 opposite to the light guide plate 13 side, that is, the lower end of the optical coupling member 30 is two lower flat surfaces. One of the two lower flat surfaces is a light incident surface 33a for receiving light from the LED chip 23a. The LED chip 23a is disposed directly below the light incident surface 33a. A spacer 25a having a height of about 0.5 mm is formed on a part of the light incident surface 33a to prevent the LED chip 23a from being damaged due to the collision between the LED chip 23a and the optical coupling member 30. The LED chip 23a is bonded to the LED substrate 24a. That is, the LED chip 23a is bonded and fixed to the LED substrate 24a by applying an adhesive or the like in the vicinity of the spacer 25a.

  Further, a recess 34 is formed in the central portion on the lower end side of the optical coupling member 30. However, the present invention is not necessarily limited to this, and a cross-sectionally semi-cylindrical shape or a semicircular cross-sectional shape in which the recess 34 does not exist may be used. That is, in the present embodiment, it is only necessary to secure an optical path to the light guide plate 13 for the light reflected by the reflecting surfaces 32 a and 32 b, so that the portion that does not become the optical path can be cut out as a recess 34. Thereby, cost reduction can be aimed at. In addition, it is also possible to provide reflection means such as a reflection sheet (not shown) in the recess 34. Thereby, even if the stray light generated in the vicinity of the top flat surface 31 may occur, a part of the stray light can be reflected to the light guide plate 13 side to improve the irradiation to the liquid crystal panel 4.

  Below the light incident surface 33a of the optical coupling member 30, an LED chip 23a bonded to the LED substrate 24a is provided in proximity. As shown in FIG. 7B, the LED chip 23a is preferably present on the end side with respect to the focal position F of the curved surface 32a made of a parabolic cross section, for example. 7A, for example, light emitted from the LED chip 23a enters the light incident surface 33a of the optical coupling member 30 and is reflected by the curved surface 32a having a parabolic cross section. Then, the reflected light reaches the top flat surface 31 of the optical coupling member 30 and enters the light guide plate 13 obliquely while maintaining the arrival direction. The light incident on the light guide plate 13 is reflected on the right side of the light guide plate 13 shown in FIG. The angle of traveling through the light guide plate 13 is changed by colliding with a light scatterer that is an optical path changing unit. And according to the advancing angle, it becomes the light by which the total reflection conditions were violated, and the light which satisfies the total reflection conditions. The light whose total reflection condition is broken is emitted from the surface of the light guide plate 13 on the liquid crystal panel 4 side, and travels toward the liquid crystal panel 4 through the diffusion sheet 2 and the prism sheet 3. On the other hand, light that satisfies the total reflection condition is not emitted from the light guide plate 13 but is reflected by the reflection sheet 12 and is reflected by the reflection sheet 12 and totally reflected inside the light guide plate 13 (Y direction in FIG. 4). The angle of traveling through the light guide plate 13 is changed by colliding with a light scatterer that is an optical path changing unit.

That is, the light incident on the light guide plate 13 is totally reflected inside the light guide plate 13 and travels toward the end portion, so that the light scattering body provided on the back surface of the light guide plate 13 acts on the liquid crystal panel 4 side of the light guide plate 13. Light with broken total reflection conditions on the surface is generated, and this light is emitted from the light guide plate 13. On the other hand, light satisfying the total reflection condition is totally reflected from the inside of the light guide plate 13 toward the end, and is emitted from the light guide plate 13 again by the action of the light scatterer provided on the back surface of the light guide plate 13 in this optical path. The light to be generated. As described above, in the light source unit 20, the light is reflected to the outside of the light guide plate 13 by changing the angle at which the incident light travels by providing a light scatterer in the optical path where the incident light is totally reflected and travels toward the end portion inside the light guide plate 13. Is emitted.

  Such an optical path is the same in the optical coupling member 30 having an elliptical cross section shown in FIG. As shown in FIG. 8B, in the optical coupling member 30 having an elliptical cross section, the LED chip 23a is preferably present on the end side with respect to the focal position F of the curved surface 32a having the elliptical cross section.

(Fixing of LED board and optical coupling member)
Next, fixing of the LED substrate 24a and the optical coupling member 30 according to the present embodiment will be described with reference to FIGS. FIG. 9 is a perspective view showing a configuration in which the light guide plate 13 in the light source unit 20 is removed. FIG. 10 is a cross-sectional view of the configuration of FIG. FIG. 11 is an enlarged cross-sectional view showing a main configuration of the A side in the configuration of FIG.

  As shown in FIGS. 9 to 11, the optical coupling member 30 is elongated in the X direction, and a cross section perpendicular to the X direction has a bifurcated shape (substantially U-shaped cross section) rooted at the top flat surface 31. Is the body. A crotch portion extending from the top flat surface 31 to the A side (one side) is disposed on the LED substrate 24a. The LED substrate 24a is screwed to the heat sink 22 by screws 34a.

  Two bosses 35a and 35a 'for fixing the light coupling member 30 and the LED substrate 24a are provided in a portion of the light coupling member 30 facing the LED substrate 24a. These bosses 35a and 35a 'are inserted into the boss holes 28a and 28a of the LED substrate 24a. The bosses 35a and 35a 'are assigned to a boss 35a bonded and fixed to the LED board 24a and a boss 35a' detachably attached to the LED board 24a. That is, of the bosses 35a and 35a ', only the boss 35a is inserted into the boss hole 28 of the LED substrate 24a and fixed with an adhesive or the like. On the other hand, the boss 35a 'is only inserted into the boss hole 28 of the LED substrate 24a.

  Further, as shown in FIG. 10, the heat sink 22 is provided with a through hole 22a communicating with the boss hole 28a of the LED substrate 24a thereon. The through hole 22a is a hole for accommodating the bosses 35a and 35a 'penetrating the boss hole 28a of the LED substrate 24a, and is a portion where excess adhesive is accumulated. The through hole 22a penetrates the heat sink 22 and is used for repair.

  No LED substrate is disposed on the B side (the other side) with respect to the top flat surface 31 of the optical coupling member 30. Two bosses 35 b and 35 b ′ for fixing the optical coupling member 30 and the heat sink 22 are provided in a portion facing the heat sink 22 at the crotch portion extending from the top flat surface 31 to the B side. As shown in FIG. 10, the heat sink 22 is provided with through holes 22b and 22b for inserting the bosses 35b and 35b '. The bosses 35 b and 35 b ′ are assigned to a boss 35 b that is bonded and fixed to the heat sink 22 and a boss 35 b ′ that is detachably attached to the heat sink 22. That is, of the bosses 35b and 35b ', only the boss 35b is inserted into the through hole 22b of the heat sink 22 and fixed with an adhesive. The through hole 22b of the heat sink 22 is used for repair.

A top flat surface 31 is formed at a portion of the optical coupling member 30 that faces the light guide plate 13. The light guide plate 13 is fixed in contact with the top flat surface 31. The top flat surface 31 is a portion that couples light from the LED substrate 24 a to the light guide plate 13.

  As shown in FIG. 9, a spacer 25 a is provided on the crotch portion of the optical coupling member 30 that extends from the top flat surface 31 toward the A side. The spacer 25a is provided to maintain a clearance between the light incident surface 33a of the light coupling member 30 and the LED substrate 24a. In addition, a spacer 25 b that contacts the heat sink 22 is provided at the crotch portion that extends from the top flat surface 31 to the B side. Since it is necessary to maintain the parallelism between the light incident surface 33a of the light coupling member 30 and the LED substrate 24a, the spacer 25b is higher than the spacer 25a by the thickness of the LED substrate 24a.

  Further, as shown in FIG. 11, a plurality of LED chips 23a are arranged inside the annular dam 26a at the joint portion of the LED substrate 24a and the optical coupling member 30. This LED chip is disposed outside the spacer 25a. The LED chip 23a is separated from the optical coupling member 30 by the spacer 25a. The spacer 23a prevents the LED chip 23a from being damaged by the collision between the LED chip 23a and the optical coupling member 30. That is, the presence of the spacer 25a makes it possible to dispose the LED chip 23a between the LED substrate 24a and the light incident surface 33a of the light coupling member 30 and to provide a gap that does not damage the LED chip 23a.

  Thus, the LED chip 23a is fixed to the optical coupling member 30 via the LED substrate 24a, the spacer 25a, and the adhesive. As a result, the LED chip 23a and the optical coupling member 30 are integrated.

  The transparent resin that seals the LED chip 23a is blocked by the dam 26, and the cured product forms the light emitting portion 23c. The light emitted from the LED chip 23a is wavelength-converted by the transparent resin cured product. For this reason, the whole light emission part 23c light-emits. The clearance between the light emitting part 23c and the light incident surface 33a of the optical coupling member 30 is set to 0.1 mm, for example. And this clearance is ensured by the above-mentioned spacer 25a. The light emitted from the LED chip 23 a enters the light incident surface 33 a, propagates through the optical coupling member 20, is totally reflected by the curved surface 32 a, reaches the top flat surface 31, and enters the light guide plate 13. An arrow Lb illustrated in FIG. 11 illustrates an example of a typical optical path from the LED chip 23a toward the light guide plate 13.

  Moreover, the following dimension is mentioned as an example of the dimension of the junction part in LED board 24a and the optical coupling member 30. FIG. That is, the width of the dam 26 in the Y direction is 1.5 mm, the thickness of the LED substrate 24 a is 2 mm, the width of the light emitting portion 23 c in the Y direction is 0.65 mm, the light incident portion 33 c and the light incident surface 33 a of the optical coupling member 30. The clearance between them is 0.1 mm.

(LED chip array on LED substrate)
By the way, in the present embodiment, as shown in FIG. 4, the light source unit 20 includes the LED chip 23 a, a rod-shaped optical coupling member 30 extending in one direction, and the light coupling unit 30 below the optical coupling member 30. The LED chip 23a is disposed along the coupling member 30, and the LED substrate 24a extends in one direction.

  In the light source unit 20 having the above configuration, the light coupling member 30 and the LED substrate 24a on which the LED chip 23a is mounted are thermally expanded by the light emission of the LED chip 23a. Here, in the present embodiment, the optical coupling member 30 is formed of, for example, acrylic resin, and a metal wiring pattern is disposed on the LED substrate 24a. For this reason, the optical coupling member 30 has a larger thermal expansion than the LED substrate 24a. As a result, when the optical coupling member 30 is tightly fixed to the LED substrate 24a, warpage occurs due to the difference in thermal expansion between them.

  Therefore, in the present embodiment, the light coupling member 30 and the LED substrate 24a are, for example, divided into eight pieces in the direction extending in parallel with the long side direction of the light guide plate 13, respectively. A seam as a gap is provided between each. For this reason, even if the optical coupling member 30 and the LED substrate 24a are thermally expanded, they expand and contract independently of each other. As a result, the optical coupling member 30 and the LED substrate 24a are not warped.

  Therefore, it is possible to provide the light source unit 20 that can suppress distortion and warpage between the optical coupling member 30 and the light source substrate due to thermal expansion in the extending direction of the optical coupling member 30.

  On the other hand, when formed in this way, the following problems occur.

  In other words, the distance between the LED chips 23a and 23a is larger between the LED boards 24a and 24a than in the LED board 24a, and cannot be more closely arranged. On the other hand, if the distance between the LED chips 23a between the LED boards 24a and 24a is applied to the distance inside the LED board 24a, the number of LED chips 23a cannot be increased.

  Specifically, for example, as shown in FIG. 13A, it is assumed that the LED chips 23a are evenly arranged on the LED substrate 24a at intervals of 2 mm. Here, the arrangement interval of the LED chips 23a may be set as appropriate according to the luminance required for the light source unit 20. For example, when higher luminance is required, the LED chips 23a may be arranged in order to increase the density of the LED chips 23a. What is necessary is just to make arrangement | positioning space | interval smaller. On the other hand, the distance between the LED chips 23a at the joint portion of the LED substrate 24a is 3 mm. The reason for this is that a margin distance from the end of the substrate that needs to be secured to form the peripheral structure of the LED chip 23a and a substrate interval for avoiding the LED substrates 24a from colliding with each other when the LED substrate 24a is thermally expanded. This is because the distance between the LED chips 23a needs to be kept at a minimum by a distance obtained by adding the distances. Therefore, for example, in FIG. 13A, it is assumed that the minimum distance required between the LED chips 23a and 23a at the joint is 3 mm. For this reason, in order to minimize the luminance unevenness, 3 mm, which is as close as possible to 2 mm of the interval in the LED chip 23a on the LED substrate 24a, is set as the interval between the LED chips 23a of the substrate joint. As a result. Since there is a gap between the LED substrates 24a and 24a, the distance between the LED chips 23a and 23a is increased by this amount.

  The luminance distribution in such a case will be described with reference to FIG. FIG. 13B is a luminance distribution diagram showing that the luminance distribution of each LED chip 23a is assumed to be a normal distribution, and the luminance distribution of each LED chip 23a is added to calculate the entire luminance distribution.

  As shown in FIG. 13 (b), at the joint of the LED substrate 24a, the interval between the LED chips 23a is large, and it can be seen that the luminance is reduced by about 30% compared to the region other than the joint. . That is, since the LED chip 23a is designed to have no unevenness at a pitch of 2 mm inside the LED board 24a, unevenness occurs between the LED boards 24a and 24a. In addition, in the center part of LED board 24a, since the LED chip 23a is 2 mm pitch, the whole brightness | luminance is uniform.

  Therefore, as shown in FIG. 14A, for example, it is conceivable to arrange a plurality of LED chips 23a in series on the LED substrate 24a so that the intervals are equal. Here, for example, the interval between the LED chips 23a on the LED substrate 24a is assumed to be 3 mm in accordance with the minimum interval distance of 3 mm at the substrate joint.

In the luminance distribution in this case, as shown in FIG. 14B, there is no portion that changes abruptly in the interval between the LED chips 23a, the fluctuation in luminance is reduced as a whole, and the luminance unevenness is reduced.

  However, as a result of the arrangement density of the LED chips 23a being smaller than in the case of FIGS. 13A and 13B, the overall luminance is reduced to 2/3, for example. As described above, the arrangement interval of the LED chips 23a is desirably set according to the luminance required for the light source unit 20, and the interval between the LED chips 23a needs to be 3 mm or less and high luminance is required to some extent. The configuration in which the LED chips 23a are simply arranged at equal intervals cannot be applied.

  Therefore, in the present embodiment, as shown in FIG. 1A, for example, two LED chips 23a are arranged in proximity to each other to constitute an LED element group G, and the intervals between the LED element groups G are equalized. Thus, the LED chip 23a is arranged. The number of LED chips 23a constituting the LED element group G need not be limited to two, and may be three or more.

  That is, for example, in the case where the luminance is required to arrange the LED chips 23a at a density of one LED chip 23a per 1.4 mm, the LED in which two or more LED chips 23a are arranged close to each other at intervals of 0.2 mm When forming the element group G, when the number of the LED chips 23a per LED element group G is two, as shown to Fig.1 (a), the space | interval of LED element group G will be 2.6 mm (LED The distance between the central positions of the element group G is 2.8 mm). When the number of LED chips 23a per LED element group G is three, the distance between the LED element groups G is 3.8 mm (not shown) (the distance between the central positions of the LED element groups G is 4.2 mm).

  Thus, it is preferable that the distance between the LED element groups G is closer to the distance between the LED chips 23a of the board joint, and as shown in FIG. 14A, the distance between the LED chips 23a at the LED joint is 3 mm. The distance between the center positions of the LED element group G composed of two LED chips 23a is preferably 2.8 mm. When the LED chips 23a are evenly arranged, the distance between the LED chips 23a needs to be 1.4 mm, whereas the distance between the center positions of the LED element groups G is 2.8 mm at the LED joint. The degree of discontinuity in the distance between the LED chips 23a can be reduced. Here, the continuity means a state in which the LED chips 23a are arranged according to a certain rule, and the regularity in which the LED element groups G are evenly arranged is hardly impaired even at the portion of the substrate joint. Therefore, the degree of discontinuity can be reduced as compared with the method in which the LED chips 23a are individually arranged.

  As a result, as shown in FIG. 1B, the luminance unevenness of the substrate seam can be greatly reduced. That is, as shown in FIG. 1B, it can be seen that the luminance of the substrate seam falls within about 10% of the luminance reduction compared to the region other than the substrate seam.

  The following generalizes the above effect.

First, the interval between the LED chips 23a at the joints of the LED substrates 24a is W, and the number of LED chips 23a arranged per unit length L on the LED substrate 24a is N. In this case, the distance between the LED chips 23a and 23a when the LED chips 23a are evenly arranged on the LED substrate 24a is L / N. On the other hand, the distance between the center positions of the LED element group G when the LED element group G in which M LED chips 23a are collected is evenly arranged is LM / N. Therefore, when LM / N is a value closer to W than L / N, it is easier to arrange the LED element group G evenly than to simply arrange the LED chips 23a evenly. The discontinuity of the arrangement of the chips 23a can be reduced, and the luminance unevenness can be improved.

Specifically, in FIG. 1A, the interval W between the LED chips 23a is 3.2 mm, the length L of one LED substrate 24a is 11.2 mm, and the number of single LED chips 23a is N. = 8, assuming that the LED chips 23a and 23a are evenly arranged in a line, the distance between the LED chips 23a and 23a is L / N = 11.2 / 8 = 1.4 mm. On the other hand, for example, M = 2
The distance between the center positions of the LED element groups G in the case where the LED element groups G collected one by one are evenly arranged with the arrangement number N = 8 of the LED chips 23a is LM / N = 11.2 × 2/8 = 2. .8.

As a result, when LM / N = 2.8 mm is closer to W = 3.2 mm than L / N = 1.4 mm, the LED element groups G are arranged evenly rather than simply arranging the LED elements 23a equally. This can reduce the discontinuity of the arrangement of the LED elements 23a at the joints of the substrates, and can improve luminance unevenness. In the above description, the LED element groups G are evenly arranged. The distance between the LED element groups G does not have to be completely constant. .

  In this case, it is conceivable that the variation in luminance at a portion other than the substrate joint becomes larger than in the method in which the LED chips 23a are simply arranged in a line. However, as shown in FIG. 1B, it can be seen that the variation in luminance is about ± 2%, which is suppressed to an extremely small level as compared with the luminance variation of the substrate seam.

  Here, in the present embodiment, as a modified example, it is possible to provide a more preferable arrangement of the LED chips 23a. This modification will be described with reference to FIGS. 15 (a) and 15 (b). 15 (a) and 15 (b), the vicinity of the substrate seam is arranged equally in the LED element group G described in FIG. 1 (a), and the central portion of the LED substrate 24a is arranged equally in a single LED chip 23a. An embodiment will be described.

  As shown in FIGS. 15A and 15B, the LED element group G in which the LED chips 23a are arranged close to each other only in the vicinity of the joint of the LED substrate 24a is arranged at equal intervals, and in the other parts, a single LED chip 23a is arranged. It is more desirable to arrange them at equal intervals.

  Here, as shown in FIGS. 15A and 15B, the distance between the LED chips 23a in the LED element group G is gradually increased from 0.1 mm toward the center of the LED substrate 24a. It is preferable to reduce the interval between the LED element groups G step by step. That is, the arrangement method of the LED chips 23a is changed stepwise from the joint portion of the substrate toward the central portion of the substrate while keeping the arrangement density of the LED chips 23a constant.

  That is, as the distance from the end of the LED substrate 24a increases, the pitch of the LED chips 23a and 23a in the LED element group G is gradually increased, that is, the arrangement density of the LED chips 23a in the LED element group G is reduced. As a result, the arrangement method can be gradually changed without changing the arrangement density of the LED chips 23. As described above, by gradually changing the pitch of the LED chips 23a in the LED element group G, the luminance distribution of the superposition can be gradually changed, and unevenness can be prevented.

  As described above, when the arrangement method of the LED chips 23a is abruptly changed, the luminance is abruptly changed at the changed portion, and the luminance unevenness is generated. However, the arrangement of the LED chips 23a over a long distance as described above. By gradually changing the method, it is possible to suppress a sudden change in luminance and reduce the occurrence of luminance unevenness.

  15A and 15B, if the size of the LED chip 23a is about 0.1 mm square, it is possible to arrange the chip intervals at 0.1 to 0.2 mm.

  The length of the LED board 24a in the present embodiment is 110 mm, for example, and in order to improve the luminance unevenness between the LED boards 24a and 24a, the LED chips for each LED element group G are arranged at 10 mm intervals on both ends of the LED board 24a. What is necessary is just to use the arrangement | sequence of 23a.

  In addition, the position of the LED chip 23a at the end of the LED board 24a can be mounted only at a position of about 1 mm from the end of the LED board 24a. For this reason, since the space between the LED substrates 24a and 24a is about 1 mm, the chip interval between the LED substrates 24a and 24a is actually about 3 mm at the minimum.

  Further, the unevenness between the LED boards 24a and 24a is visually recognized because there is a sudden increase / decrease in brightness of about ± 5 mm between the LED boards 24a and 24a. However, it is relatively difficult to visually recognize that the light gradually changes in the LED substrate 24a.

  In the present embodiment, for example, the number of chips in one LED substrate 24a is, for example, 72, and the pitch can be about 1.5 mm. 13A and 13B, there is a method in which the number of chips is increased only at the end of the LED substrate 24a. However, the increase in the number of chips increases the amount of light but increases the cost. For this reason, an unequal pitch arrangement that can reduce joint unevenness without changing the total chip amount is preferable.

(Application to liquid crystal display devices)
As described above, the light source unit 20 of the present embodiment can be applied to the liquid crystal display device 1 as shown in FIGS. In this case, the light source units 20 shown in FIG. 4 are arranged and used in the X direction. As a result, the light guide plate 13 is also configured with large dimensions in both the X direction and the Y direction. By adopting such a configuration, the area of the light guide plate 13 is increased corresponding to the increase in the area of the liquid crystal panel 4 of the liquid crystal display device, and a backlight suitable for practical use of the large-screen liquid crystal display device 1 is realized. can do.

  For example, eight heat sinks having a length of 110 mm, a width of 100 mm, and a thickness of 2 mm are used, and a set of eight heat sinks 22, an optical coupling member 30, and an LED substrate 24 a is arranged on the large heat guide 22. It is possible to constitute a surface light emitting device of a type that fixes the light plate 13 and a backlight type liquid crystal display device 1 that illuminates the liquid crystal panel 4 from the back side.

  In the present embodiment, the backlight 10 is applied to the liquid crystal display device 1. However, the present invention is not necessarily limited thereto, and for example, the backlight 10 can be applied to a lighting device. That is, the backlight 10 of the present embodiment can be applied to a large planar light source as it is. Further, since no member is required around the light guide plate 13, it can be applied to a larger planar light source by arranging them seamlessly.

  As described above, the backlight 10 of the present embodiment includes at least the light guide plate 13 as an optical member and the LED chips 23a as a plurality of light sources arranged along the light guide plate 13, and the LED chip 23a. The light incident on the light guide plate 13 is emitted from the surface of the light guide plate 13 while guiding the inside of the light guide plate 13. A plurality of LED substrates 24a as light source substrates on which a plurality of LED chips 23a are arranged are arranged in series.

In such a case, the LED chip 23a cannot be disposed at each end of the LED substrate 24a due to the necessity of forming a peripheral structure such as a wiring. It has a problem that it occurs.

  Therefore, in the present embodiment, an LED element group G in which a plurality of LED chips 23a are gathered and arranged close to each other is formed at the end of each LED substrate 24a, and the LED per unit length L of the LED substrate 24a. When the LED element group G, in which M pieces of LED chips 23a are collected, is arranged evenly on the LED board 24a so that the LED chips 23a are arranged on the LED board 24a with a light source density where N chips 23a are arranged The distance LM / N between the center positions of the LED element groups G in FIG. 2 is larger than the distance L / N between the LED chips 23a and 23a when N LED chips 23a are evenly arranged on the LED substrate 24a with the light source density. The value is close to the interval W between the LED chips 23a and 23a between the LED substrates 24a and 24a.

  That is, even in a structure in which a plurality of LED substrates 24a are arranged, the LED element group G is arranged evenly between the LED substrates 24a and 24a rather than simply arranging the LED chips 23a evenly. The discontinuity of the arrangement can be reduced and the luminance unevenness can be improved.

  Therefore, even when a plurality of LED substrates 24a in which a plurality of LED chips 23a are arranged side by side are arranged in series with each other, it is possible to provide the backlight 10 that can suppress the occurrence of luminance unevenness.

  Moreover, in the backlight 10 of this Embodiment, the space | interval of LED element group G in the edge part of each LED board 24a is mutually uniform.

  Thereby, according to the space | interval of the LED element group G between LED board 24a * 24a, the LED element group G in LED board 24a can be arrange | positioned at equal intervals. As a result, it is possible to suppress the occurrence of luminance unevenness due to the LED substrate 24a and the discontinuous change in the arrangement of the LED chips 23a at the ends of the LED substrate 24a.

  Moreover, in the backlight 10 of this Embodiment, the density of the LED chip 23a in each LED element group G in the edge part of each LED board 24a seems to increase in steps from the center side of this LED board 24a to the terminal. It can be assumed that

  Thereby, the LED chip 23a in the center of the LED substrate 24a is individually arranged for each one from the state in which the plurality of LED chips 23a in the vicinity of the end portion of the LED substrate 24a are collected and arranged for each LED element group G arranged in proximity. It can be continuously changed to the state to be.

  Therefore, in the backlight 10 of the present embodiment, the plurality of LED chips 23a are arranged in series in the center of each LED substrate 24a, and the intervals between the LED chips 23a are uniform with each other. can do.

  For this reason, it is possible to prevent uneven brightness due to the arrangement of the LED chip 23a for each LED element group G. Further, since the arrangement state gradually changes to the arrangement state of the LED chips 23a for each LED element group G at the end of the LED substrate 24a, luminance unevenness does not occur during the change of the arrangement state.

In the backlight 10 according to the present embodiment, the optical member has a flat plate shape, and the light guide plate 13 that emits light from the upper surface while guiding incident light by totally reflecting the light inside, and the light guide plate 13. And an optical coupling member 30 that couples light so that light enters the light guide plate 13 from the top flat surface 31 on the lower surface of the light guide plate 13. Further, the LED chip 23 a is disposed so as to emit incident light to the optical coupling member 30 from below the optical coupling member 30.

  Thereby, the light emitted from the LED chip 23a below the light guide plate 13 is incident on the light guide plate 13 via the optical coupling member 30, and a part of the light is reflected while totally reflecting the inside of the light guide plate 13. While propagating to the end of 13, the total reflection condition is broken by an optical path conversion element in the middle, and the light is emitted from the upper surface of the light guide plate 13.

  As a result, unlike the conventional side edge type light guide plate, the backlight is directly under the light guide plate. Therefore, the LED chip 23a and the light guide for avoiding the thermal expansion required in the side edge type light guide plate are provided. A gap with the light plate 13 becomes unnecessary, so that the coupling efficiency from the LED chip 23a to the light guide plate 13 can be increased, and the light utilization efficiency can be improved.

  Further, in the present embodiment, by providing the light coupling member 30 that is separate from the light guide plate 13, light is incident from the top flat surface 31 on the lower surface of the flat light guide plate 13. Then, the incident light is guided while being totally reflected. As a result, there is no need to process the light guide plate 13, the coupling efficiency from the LED chip 23a to the light guide plate 13 can be increased, the light utilization efficiency can be improved, and the manufacturing cost can be reduced.

  Further, the liquid crystal display device 1 of the present embodiment includes the light source module of the present embodiment as the backlight 10.

  Therefore, even when a plurality of LED substrates 24a each having a plurality of LED chips 23a arranged side by side are arranged in series with each other, a liquid crystal display provided with a light source module that can more appropriately suppress the occurrence of luminance unevenness A device 1 can be provided.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIGS. The configurations other than those described in the present embodiment are the same as those in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and explanation thereof is omitted.

  In the first embodiment, the LED chips 23a of the light source unit 20 are arranged in one row on the LED substrate 24a. However, in the present embodiment, the LED chips 23a of the light source unit are arranged in two rows. The point is different.

  That is, in the light source unit 20 ′ in the backlight 10 of the present embodiment, as shown in FIG. 17, the LED boards 24a and 24b are fixed to the two crotch portions extending from the top flat surface of the optical coupling member 30 to both sides. LED chips 23a and 23b are provided on the LED substrates 24a and 24b, respectively. These LED chips 23 a and 23 b are arranged so that the optical axis direction of the emitted light, that is, the direction with the highest luminance in the incident light is orthogonal to the flat light guide plate 13. As a result, the backlight 10 of the present embodiment is a backlight 10 directly under the light source in which the LED chips 23 a and 23 b are provided below the light guide plate 13.

Here, in the liquid crystal display device 1, the light source unit 20 ′ is provided at the end of the light guide plate 13 as shown in FIG. 17. Accordingly, the light from the LED chip 23a is incident on the right side of the light guide plate 13 via the optical coupling member 30 as shown in FIG. Don't head right. On the other hand, the light from the LED chip 23b is incident on the left side of the light guide plate 13 through the optical coupling member 30, as shown in FIG. However, as shown in FIG. 17, a positioning pin 14 is provided on the left side of the light guide plate 13 and immediately becomes the lower end portion 13 a of the light guide plate 13. For this reason, as shown in FIG. 18, the light incident in the left direction of the light guide plate 13 through the optical coupling member 30 immediately reaches the lower end portion 13a of the light guide plate 13, and at the lower end portion 13a. Reflected. As a result, the light reflected by the lower end portion 13a of the light guide plate 13 travels toward the right end of the light guide plate 13 while being totally reflected inside the light guide plate 13 like the light from the LED chip 23a. . Thus, when the LED chips 23a and 23b are arranged in two rows along the light incident surfaces 33a and 33b of the optical coupling member 30 formed of a belt-like body having a substantially U-shaped cross section, the LED chips 23a arranged in two rows are arranged. -Light can be guided by increasing the amount of light inside the light guide plate 13 by 23b.

  As a result, in the present embodiment, by providing the strip-shaped light source unit 20 ′ across the edge of the screen of the liquid crystal display device 1, it is possible to obtain a uniform and smooth luminance distribution in the liquid crystal panel 4. Become.

  In the backlight 10, light from the LED chips 23 a and 23 b is introduced from below the light guide plate 13. For this reason, the light use efficiency of the conventional side edge type backlight is about 75%, for example, whereas the light use efficiency of the backlight 10 of the present embodiment is about 88%. Therefore, the light use efficiency is superior to the conventional side edge type backlight.

  Further, unlike the conventional side edge type backlight, the backlight 10 does not have a light source at the end of the liquid crystal panel 4. For this reason, as shown in FIG. 19, the frame 6 can be provided directly at the end of the liquid crystal panel 4. As a result, the frame size can be reduced to, for example, 6 mm or less, and the frame can be narrowed.

  Thus, in the liquid crystal display device 1 of this Embodiment, the liquid crystal panel 4, the light guide plate 13, the optical coupling member 30, and LED chip 23a * 23b are arrange | positioned in this order. That is, in the liquid crystal display device 1, the LED chips 23a and 23b are provided below the light guide plate 13, and light emitted from the LED chips 23a and 23b is guided between the light guide plate 13 and the LED chips 23a and 23b. An optical coupling member 30 that couples light so that light enters from the top flat surface 31 on the lower surface of the optical plate 13 is provided. For this reason, the light emitted from the LED chips 23 a and 23 b below the light guide plate 13 is incident on the light guide plate 13 via the optical coupling member 30, and is reflected from the end of the light guide plate 13 while totally reflecting the inside of the light guide plate 13. The total reflection condition is broken by an optical path conversion element (not shown) in the middle of the movement, and the light is emitted from the light guide plate 13, reflected by the reflection sheet 12, and further passed through the light guide plate 13. The light exits from the surface of the liquid crystal panel 4 and travels toward the liquid crystal panel 4 through the diffusion sheet 2 and the prism sheet 3.

  As a result, unlike the conventional side edge type light guide plate, the backlight is directly under the light guide plate, so that the frame size can be reduced and the design effect can be improved. Further, since the gap between the LED chips 23a and 23b and the light guide plate 13 for avoiding the thermal expansion necessary for the side edge type light guide plate is not required, light does not leak from the gap. That is, in the liquid crystal display device 1, since the light coupling member 30 and the LED chips 23a and 23b are disposed below the light guide plate 13, the thickness direction of the light guide plate 13 is smaller in thermal expansion than the long or short planar direction. . Therefore, the expansion and contraction of the light guide plate 13 is small, and the optical coupling member 30 and the LED chips 23a and 23b can be brought close to each other. For example, the gap between the optical coupling member 30 and the LED chips 23a and 23b can be set to 0.5 mm or less, for example. Since the optical coupling member 30 is in contact with the light guide plate 13, there is no gap. For this reason, the coupling efficiency from LED chip 23a * 23b to the light-guide plate 13 can be improved, and light utilization efficiency can be improved.

In the present embodiment, by providing the light coupling member 30 that is separate from the light guide plate 13, light is incident on the flat light guide plate 13 at an angle, so that incident light is incident inside the light guide plate 13. The light is guided while being totally reflected.

  In other words, in this embodiment, the optical coupling member 30 is a strip-like body having a substantially U-shaped cross section in which the top flat surface 31 contacts the light guide plate 13.

  As a result, incident light from the LED chips 23a and 23b via the optical coupling member 30 can be guided inside the light guide plate 13 without processing the light guide plate. For this reason, since light guide plate 13 itself is sufficient with a simple flat plate, processing for large light guide plate 13 is not required. Moreover, although it is difficult to process the light guide plate 13, the processing of the optical coupling member 30 is easier than that, and the manufacturing cost can be reduced.

  In the liquid crystal display device 1, the optical coupling member 30 is provided at the end of the light guide plate 13. As a result, light from the LED chips 23a and 23b is incident on the end of the light guide plate 13, so that the light guide plate 13 guides light in one direction, and the light is extracted from the entire surface of the light guide plate 13. The entire surface of the liquid crystal panel 4 can be irradiated.

  Therefore, the backlight 10 and the liquid crystal display device 1 that can increase the coupling efficiency from the LED chips 23a and 23b to the light guide plate 13 and improve the light utilization efficiency without processing the light guide plate 13 can be provided.

  Further, in the backlight 10 of the present embodiment, the light coupling member 30 causes light to enter the light guide plate 13 obliquely. Accordingly, light is incident on the flat light guide plate 13 at an angle, so that the incident light is guided inside the light guide plate 13 while being totally reflected. As a result, it is not necessary to process the light guide plate, the coupling efficiency from the LED chips 23a and 23b to the light guide plate 13 can be increased, the light utilization efficiency can be improved, and the manufacturing cost can be reduced.

  Moreover, in the backlight 10 of this Embodiment, the optical coupling member 30 has the curved surfaces 32a and 32b which are reflective surfaces, and the incident light from LED chip 23a and 23b is reflected by the curved surfaces 32a and 32b, and is guide | induced. Light is incident on the light plate 13. Thereby, the light radiate | emitted from LED chip 23a * 23b injects into the optical coupling member 30, and reflects on the curved surfaces 32a * 32b. The light reflected by the curved surfaces 32 a and 32 b is coupled so as to enter the light guide plate 13 from the top flat surface 31 on the lower surface of the light guide plate 13.

  As a result, the light from the LED chips 23a and 23b can be efficiently coupled and incident on the light guide plate 13 by the light coupling member 30 having the curved surfaces 32a and 32b without processing the light guide plate 13.

  Moreover, in the backlight 10 of this Embodiment, the optical coupling member 30 makes light inject into the light guide plate 13 so that it may be totally reflected within the light guide plate 13. Thereby, the backlight 10 which can improve light utilization efficiency can be provided.

  Further, in the present embodiment, the LED chips 23 a and 23 b are arranged so that the optical axis direction of the incident light to the optical coupling member 30 is orthogonal to the flat light guide plate 13. For this reason, since it is not necessary to make LED chip 23a * 23b arrangement | positioning with respect to the flat light-guide plate 13, arrangement | positioning of LED chip 23a * 23b is also easy and a structure and an assembly method are simple.

  Therefore, it is possible to provide the backlight 10 and the liquid crystal display device 1 that can increase the coupling efficiency from the LED chips 23a and 23b to the light guide plate 13 and improve the light utilization efficiency without processing the light guide plate 13. .

  Moreover, in the backlight 10 of this Embodiment, LED chip 23a * 23b is provided in 2 rows along the longitudinal direction of the optical coupling member 30. FIG. Specifically, the LED chips 23a and 23b are provided in two rows in parallel along the center line immediately below both ends of the lower end chord in the optical coupling member 30 having a substantially U-shaped cross section.

  As a result, when the light is incident on the light guide plate 13, the two rows of LED chips 23a and 23b emit light in opposite directions, so that the line passing through the midpoint between the two rows is axially symmetric and both sides of the optical coupling member 30. That is, the light can be guided to both ends of the light guide plate 13. Therefore, the luminance distribution can be made uniform in the light guide plate 13 with a simple structure.

  Moreover, in the backlight 10 of this Embodiment, the light source consists of several LED chip 23a * 23b. The LED chips 23a and 23b are small in shape and can be densely arranged at a minute interval. As a result, the LED chips 23a and 23b are small in shape and large in illuminance, and thus are suitable as a light source for the backlight 10.

  In the present embodiment, the light guide plate 13 is not processed and light is incident from below, so that the liquid crystal display device 1 can be thinned. Specifically, a certain amount of thickness is required for processing the light guide plate 13. In this case, the conventional edge light system has a limit in reducing the thickness because the light coupling rate decreases when the light guide plate is made thinner than the width of the light source. In this respect, in the present embodiment, if the light guide plate 13 is thinned, the television is thinned and lightened. Moreover, since the material of the light guide plate 13 can be saved, the cost can be reduced from the point that processing is unnecessary. Further, since the LED chips 23a and 23b may be mounted upward, the assembly direction of the member groups constituting the liquid crystal display device 1 including the LED chips 23a and 23b may be one assembling direction. As a result, the assembly manufacturing apparatus configuration and the assembly work are simplified.

  That is, in the case of the conventional edge light, since it is necessary to attach the light source from the side, the liquid crystal display device as a whole is one direction of incorporation, and manufacturing is somewhat difficult.

  Moreover, in this Embodiment, the optical coupling member 30 is provided in strip | belt shape. Further, the optical coupling member 30 provided in the belt shape is provided in parallel to the longitudinal direction of the light guide plate 13 having a rectangular flat plate shape.

  Thereby, it is not necessary to make the relationship between the optical coupling member 30 and the plurality of LED chips 23a and 23b 1: 1, and the plurality of LED chips 23a and 23b are covered with one optical member. It can be simplified. Moreover, since LED chip 23a * 23b can also be provided along the optical coupling member 30, the wiring of LED chip 23a * 23b becomes easy.

  In addition, the optical coupling member 30 may be composed of a single linear member in the longitudinal or lateral direction, that is, the longitudinal direction or the lateral direction in the rectangular flat light guide plate 13. The separated pieces of the optical coupling member may be arranged in a straight line in a strip shape.

  Accordingly, it is not necessary to provide one optical element for one light source, and a plurality of light sources are covered with one optical member, so that the structure of the optical system can be simplified. In addition, the light source may be of the type housed in a package, but a semiconductor chip shape can also be applied. The light source is disposed along the optical coupling member, and wiring of the light source is facilitated.

By the way, in the backlight 10, as shown in FIG. 17, the flat chassis 11 which hold | maintains the light-guide plate 13 in a plane is provided under the light-guide plate 13. As shown in FIG. And chassis 11
The light guide plate holding surface has an opening (opening 11 a in FIG. 2) in the vicinity of the position where the optical coupling member 30 contacts the light guide plate 13. The optical coupling member 30 and the LED chips 23 a and 23 b are located below the light guide plate holding surface of the chassis 11. That is, in the present embodiment, as shown in FIG. 20A, a separate light source holder 21 is joined to the chassis 11 having the opening 11a, whereby the light coupling member 30 and the LED chips 23a and 23b are joined. Is located below the light guide plate holding surface 11 b of the chassis 11. However, the present invention is not necessarily limited to this. For example, as shown in FIG. 20B, it is possible to provide a recess in the chassis 11 and mount the LED chips 23 a and 23 b and the optical coupling member 30 in the recess. Also in this case, the optical coupling member 30 and the LED chips 23 a and 23 b are located below the light guide plate holding surface 11 b of the chassis 11.

  With such a configuration, only the optical coupling member 30 and the LED chips 23a and 23b protrude on the back side of the light guide plate 13. Accordingly, it is possible to reduce the thickness of portions other than the optical coupling member 30 and the LED chips 23a and 23b. For this reason, the overall thickness can be reduced. Furthermore, by setting it as such a structure, it becomes the thing excellent also in the surface of heat dissipation of LED chip 23a * 23b. Further, by connecting the light source unit 20 ′ to the chassis 11, the chassis 11 functions as a heat radiating plate, so that high heat radiating performance can be obtained. As a result, the light emission efficiency of the LED chips 23a and 23b is also improved.

[Embodiment 3]
The following will describe still another embodiment of the present invention with reference to FIGS. The configurations other than those described in the present embodiment are the same as those in the first embodiment and the second embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiment 1 and Embodiment 2 are given the same reference numerals, and explanation thereof is omitted.

  In the backlight 10 of the first embodiment and the second embodiment, the light source unit 20 is provided at the end of the light guide plate 13. However, in the backlight of the present embodiment, the light source unit 20 ′ is the light guide plate 13. The point provided on the center line is different.

  That is, the backlight 10 ′ as the light source module in the liquid crystal display device 1 of the present embodiment is arranged just below the center of the liquid crystal panel 4 as shown in FIGS. 17 is different from the liquid crystal display device 1 shown in FIG.

  As shown in FIGS. 21A and 21B, the liquid crystal display device 1 includes a VESA frame 40, a backlight 10 ′, a diffusion plate 2A, a prism sheet 3, a diffusion sheet 2B, a liquid crystal panel 4 and a bezel 5 in this order. They are placed one on top of the other.

  The backlight 10 ′ is composed of a chassis 11, a reflection sheet 12, and a light guide plate 13 to which the light source unit 20 ′ is attached in order from the bottom, that is, in order from the far side from the liquid crystal panel 4.

  The chassis 11 increases the strength of the backlight 10 '. The chassis 11 is substantially the same size as the liquid crystal panel 4 and has a flat plate shape excluding the recess 11a. A plane of the flat plate-like portion of the chassis 11 on the light guide plate 13 side is a light guide plate holding surface that holds the reflection sheet 12 and the light guide plate 13.

The recess 11 a is a long (strip-shaped) groove extending in a direction parallel to the long side of the liquid crystal panel 4, and is formed at a position facing the central portion of the liquid crystal panel 4 in the short side direction. That is,
The recess 21 a is disposed along the longitudinal direction, which is the horizontal direction of the liquid crystal panel 4, and so as to face the center line in the short direction, which is the vertical direction of the liquid crystal panel 4.

  Then, on the bottom surface of the recess 21a, which is a stepped portion, for example, a light source unit 20 'composed of a plurality of LED substrates and the light coupling member 30 is arranged in a line along the longitudinal direction of the recess 21a. Installed.

  In addition, as described in the second embodiment, the light source unit 20 ′ includes the two LED substrates 24a and 24b on which the LED chips 23a and 23b as the light sources are mounted, the long optical coupling member 30, and the like. And a heat sink 22.

  In the backlight 10 ′ having the above configuration, as shown in FIG. 22, the light emitted from the LED chip 23 b is reflected by a curved surface 32 a such as a cross-sectional ellipse of the optical coupling member 30, and the reflected light is reflected by the optical coupling member 30. It reaches the top flat surface 31 and enters the light guide plate 13 obliquely while maintaining the direction of arrival. Then, the light incident on the light guide plate 13 travels through the light guide plate 13 by colliding with a light scatterer which is an optical path changing unit (not shown) while being totally reflected on the inner right side of the light guide plate 13 shown in FIG. The advancing angle is changed, the total reflection condition is broken, the light is emitted from the light guide plate 13, is reflected by the reflection sheet 12, further passes through the light guide plate 13, and is emitted from the surface of the light guide plate 13 on the liquid crystal panel 4 side, It goes to the liquid crystal panel 4 through the diffusion sheet 2 and the prism sheet 3. On the other hand, the light emitted from the LED chip 23b also proceeds symmetrically with the light from the LED chip 23a in the light guide plate 13, as shown in FIG.

  As a result, in the backlight 10 ′ in the liquid crystal display device 1 of the present embodiment, the strip-shaped light source unit 20 ′ is provided across the central portion of the screen of the liquid crystal display device 1, so that FIGS. The light emitted from the light guide plate 13 having the luminance distribution shown in FIG. The luminance distribution that the center of the screen is bright matches the luminance distribution for displaying the liquid crystal display device 1 appropriately. For this reason, in the present embodiment, it is possible to obtain a uniform and smooth luminance distribution. As a result, it can be said that it is superior to the conventional side edge type backlight.

[Embodiment 4]
The following will describe still another embodiment of the present invention with reference to FIG. The configurations other than those described in the present embodiment are the same as those in the first to third embodiments. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiments 1 to 3 are given the same reference numerals, and descriptions thereof are omitted.

  In the first to third embodiments, the light source unit 20 is provided below the light guide plate 13.

  However, the light source module of the present invention is characterized in that the LED element group G composed of a plurality of LED chips 23a is arranged on the LED substrate 24a at equal intervals. Therefore, the light source module of the present invention includes only the light guide plate 13 as an optical member even though the light guide plate 13 and the optical coupling member 30 are not provided as the optical members shown in the first to third embodiments. Even so, it can be applied.

  That is, as shown in FIG. 24, the backlight 10 ″ as the light source module of the present embodiment has a dam 26a made of a white resin formed on the surface of the LED substrate 24a. An LED chip 23a is disposed inside.

  As described above, in the backlight 10 '' as the light source module of the present embodiment, the LED substrate 24a is disposed to face the side surface of the light guide plate 13, and light is directly emitted from the LED chip 23a to the side surface of the light guide plate 13. Is incident.

  Therefore, the backlight 10 ″ of the present embodiment can be applied to a conventional general edge light system.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  The present invention can be used for a backlight of a liquid crystal display device such as a television or a monitor, and is particularly applicable to a backlight directly under the light source. The backlight can be applied to a lighting device as a large planar light source.

1 Liquid crystal display device 10 Backlight (light source module)
10 'backlight (light source module)
10 '' backlight (light source module)
13 Light guide plate (optical member)
20 Light source unit 20 ′ Light source unit 23a / 23b LED chip (light source)
24a / 24b LED board (light source board)
30 Optical coupling member (optical member)
31 Top flat surface (incident part)
32a and 32b Curved surfaces 33a and 33b Light incident surface G LED element group (light source group)

Claims (6)

An optical member, and a plurality of light sources arranged along the optical member, and light incident on the optical member from the light source is emitted from the surface of the optical member while guiding the inside of the optical member. In the light source module
A plurality of light source substrates in which the plurality of light sources are arranged side by side are arranged in series with each other,
A light source group in which a plurality of light sources are gathered and arranged close to each other is formed at the end of each light source substrate, and the light source density is such that N light sources are arranged per unit length L of the light source substrate. The distance LM / N between the central positions of the light source group when the light source group, in which M light sources are collected M, is evenly arranged on the light source substrate so that the light sources are arranged, The light source module is characterized in that it has a value closer to the interval between the light sources between the light source substrates than the interval L / N between the light sources when evenly arranged on the light source substrate.   The light source module according to claim 1, wherein the distance between the light source groups at the end of each light source substrate is uniform.   2. The light source module according to claim 1, wherein the density of the light sources in each light source group at the end of each light source substrate is set to increase stepwise from the center side to the end of the light source substrate. .   The plurality of light sources are arranged in a line in a central portion of each of the light source substrates, and the intervals between the light sources are uniform with each other. 3. The light source module according to 3. The optical member has a flat plate shape, and is provided on the lower side of the light guide plate, the light guide plate that emits light from the upper surface while totally reflecting incident light inside and guiding the light. It is composed of an optical coupling member that couples light so that light is incident on the light guide plate from the incident portion on the lower surface,
The light source module according to claim 1, wherein the light source is disposed so as to emit incident light to the optical coupling member from a lower side of the optical coupling member.   A liquid crystal display device comprising the light source module according to claim 1 as a backlight.

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