JP2020102341A - Integrated light emitting device - Google Patents

Abstract

To provide an integrated light emitting device suitable for a local dimming operation.SOLUTION: An integrated light emitting device comprises: a substrate; plural light emission elements 120 two-dimensionally aligned on a substrate upper face 110a in first and second directions; plural first inclined faces 131 extending in the first direction and plural second inclined faces 132 extending in the second direction, being transparent partition members having plural inclined faces. Each of them has plural light emission parts CP including one of the plural light emission elements, and the first inclined face 131 and the second inclined face 132 surrounding the light emission element. Each of the first inclined faces 131 and each of the second inclined faces 132 included in each of the light emission part CP in a rectangular form have one or more first regions 131a, 132a, and second regions 131b, 132b indicating permeability lower than the first regions. The second region 131b of each first inclined face is positioned at a center part in the first direction, and the second region 132b of each second inclined face is positioned at a center part in the second direction.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to an integrated light emitting device including a plurality of light emitting elements.

A direct type light emitting device is known as a backlight used in a liquid crystal display device or the like (see, for example, Patent Documents 1, 2 and 3 below). The direct type light emitting device has a structure in which a plurality of light sources are arranged two-dimensionally, and it is easier to obtain a high contrast ratio than an edge type light emitting device in which light is incident from the side surface of the light guide plate. Taking advantage of this feature, it has also been proposed to divide the light emitting surface into a plurality of light emitting regions and obtain a higher contrast ratio by a local dimming operation in which lighting and extinguishing in these light emitting regions are individually controlled.

JP 2012-216762 A JP, 2007-207759, A JP, 2014-203675, A

In the field of display devices, there is a demand for improving the contrast ratio.

An integrated light emitting device of the present disclosure includes a substrate having an upper surface, and a plurality of light emitting elements arranged two-dimensionally on the upper surface side of the substrate along a first direction and a second direction orthogonal to the first direction. A translucent partition member located on the upper surface side of the substrate and having a plurality of inclined surfaces, wherein the plurality of inclined surfaces each include a plurality of first inclined surfaces extending in the first direction; A partitioning member each including a plurality of second inclined surfaces extending in the second direction, and a wiring located between the upper surface of the substrate and the partitioning member and electrically connected to the plurality of light emitting elements. A layer, each including one of the plurality of light emitting elements, and a set of the first inclined surface and a set of the second inclined surface that surrounds the one light emitting element in a rectangular shape in a top view. Each of the first inclined surfaces and each of the second inclined surfaces included in each light emitting portion has a plurality of light emitting portions, and each of the first and second first inclined surfaces includes one or more first regions and the one or more first inclined surfaces for light from the light emitting element. A second region showing a lower transmittance than the region, and the second region of each first inclined surface included in each light emitting unit has a central portion in the first direction when viewed from the upper surface side of the substrate. And the second region of each second inclined surface included in each light emitting unit is located at the central portion in the second direction when viewed from the upper surface side of the substrate.

According to the embodiments of the present disclosure, an integrated light emitting device particularly suitable for local dimming operation is provided.

FIG. 3 is an exploded perspective view schematically showing a liquid crystal display device including a part of the integrated light emitting device according to the embodiment of the present disclosure. FIG. 3 is a schematic cross-sectional view showing an enlarged cross-section when one of the light emitting parts CP shown in FIG. 1 is cut perpendicularly to an upper surface 110 a of a substrate 110. FIG. 6 is a schematic perspective view showing one of a plurality of light emitting parts CP taken out and enlarged. FIG. 6 is a diagram showing an example of a wiring pattern of a wiring layer 140. FIG. 6 is a schematic top view showing an example of the external appearance of a plurality of light emitting parts CP of the integrated light emitting device 100 when viewed from the normal direction of the substrate 110. In a backlight unit of a comparative example having a plurality of light emitting areas divided by a grid-like reflecting member, it is a diagram schematically showing a block-shaped light emitting pattern that occurs when one of the light emitting areas is turned on. .. FIG. 4 is a schematic cross-sectional view for explaining the mechanism of block-shaped noise generation. It is a typical sectional view for explaining an example of composition of a division member. It is a typical perspective view showing other examples of arrangement of the 1st field 131a in the 1st slope 131, and the 1st field 132a in the 2nd slope 132. FIG. 16 is a schematic cross-sectional view showing a modified example of the integrated light emitting device according to the embodiment of the present disclosure. FIG. 16 is a schematic cross-sectional view showing another modified example of the integrated light emitting device according to the embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following embodiments are examples, and the integrated light emitting device according to the present disclosure is not limited to the following embodiments. For example, the numerical values, shapes, materials, steps, order of the steps, and the like shown in the following embodiments are merely examples, and various modifications are possible as long as there is no technical contradiction.

The dimensions, shapes, etc. of the components shown in the drawings may be exaggerated for the sake of clarity, and may not reflect the dimensions, shapes, and size relationships between the components in an actual integrated light-emitting device. .. In addition, in order to avoid making the drawings excessively complicated, some elements may not be shown.

In the following description, constituent elements having substantially the same function are designated by common reference numerals, and description thereof may be omitted. In the following description, terms indicating a particular direction or position (for example, “upper”, “lower”, “right”, “left” and other terms including those terms) may be used. However, those terms only use the relative orientation or position in the referenced figures for clarity. In the drawings other than the present disclosure, the actual product, the manufacturing apparatus, etc., the same as the referenced drawings, as long as the relative directions or positions in terms of “upper”, “lower”, etc. in the referenced drawings are the same. It does not have to be arranged. In the present disclosure, “parallel” includes a case where two straight lines, sides, surfaces, etc. are in the range of 0° to ±5° unless otherwise specified. Further, in the present disclosure, “vertical” or “orthogonal” includes the case where two straight lines, sides, surfaces, etc. are in the range of about 90° to ±5° unless otherwise specified.

(First embodiment)
FIG. 1 schematically illustrates a liquid crystal display device including an integrated light emitting device according to an embodiment of the present disclosure as a part thereof. For reference, arrows indicating the x-direction, the y-direction, and the z-direction that are orthogonal to each other are drawn in FIG. These arrows may also be shown in other drawings of the present disclosure.

The liquid crystal display device 300 illustrated in FIG. 1 schematically includes an integrated light emitting device 100 and a liquid crystal panel 200 arranged above the integrated light emitting device 100. The integrated light emitting device 100 includes a substrate 110 having an upper surface 110a, a plurality of light emitting elements 120 arranged on the upper surface 110a side of the substrate 110, and a partitioning member 130 having a plurality of inclined surfaces 130s. In this example, the integrated light emitting device 100 further includes a light diffusion sheet 150 located between the partition member 130 and the liquid crystal panel 200.

The plurality of light emitting elements 120 are two-dimensionally arranged on the upper surface 110a side of the substrate 110 along a certain first direction and a second direction orthogonal to the first direction. FIG. 1 shows an example in which a total of 16 light emitting devices 120 are arranged in four rows and four columns in order to avoid making the drawing excessively complicated. Although not shown in FIG. 1, the integrated light emitting device 100 also has a wiring layer that supplies a predetermined current to each of the plurality of light emitting elements 120.

In this example, the center of the light emitting element 120 is located on the lattice point of the square lattice. Needless to say, the number of light emitting elements 120 and their arrangement are not limited to the example shown in FIG. For example, the plurality of light emitting elements 120 may be arranged such that the centers of the light emitting elements 120 are located on the lattice points of the triangular lattice. A direction inclined by 60° with respect to the first direction may be selected as the second direction. That is, the plurality of light emitting elements 120 may be arranged on the upper surface 110a of the substrate 110 such that the centers of the light emitting elements 120 are located on the lattice points of the hexagonal lattice.

The partition member 130 has a substantially translucent structure, and is located on the upper surface 110a side of the substrate 110, like the plurality of light emitting elements 120. The partitioning member 130 has a plurality of inclined surfaces 130s and partitions a region on the upper surface 110a of the substrate 110 into a plurality of light emitting units CP each including at least one of the plurality of light emitting elements 120. In this specification, the terms "translucent" and "translucent" mean that at least a part of incident light is transmitted, and also includes exhibiting diffusibility with respect to incident light. As widely interpreted. That is, it is not limited to being “transparent”.

The integrated light emitting device 100 is housed in the back chassis of the liquid crystal display device 300, for example. The light diffusion sheet 150 is located above the light emitting device 120 and may be supported by the back chassis. The light diffusion sheet 150 may be in contact with the partition member 130 or may be separated from the partition member 130.

According to the embodiment of the present disclosure, since the partitioning member 130 that defines each light emitting unit CP includes a translucent portion, the light emitting unit in the xy plane in a direction different from the first direction and the second direction. Moderate light leakage from the CP can be tolerated. Further, as will be described later, the inclined surfaces 130s of the partition member 130 have a relatively low transmittance in the central portion in the first direction and the central portion in the second direction when viewed from the upper surface 110a side of the substrate 110. Has an area. By providing each inclined surface 130s with a region having a relatively low transmittance, light leakage to the closest light emitting unit CP is reduced. As a result, the block-shaped light emitting pattern caused by the leakage of light between the light emitting portions CP is relaxed, and the shape of the bright region on the light emitting surface can be made closer to a circle.

Hereinafter, each component of the integrated light emitting device 100 will be described in detail. FIG. 2 shows a cross section when one of the light emitting portions CP shown in FIG. 1 is cut perpendicularly to the upper surface 110 a of the substrate 110. FIG. 3 shows one of the plurality of light emitting units CP in an enlarged manner.

[Substrate 110]
The substrate 110 supports the plurality of light emitting elements 120 arranged on the upper surface 110a side. The substrate 110 may be a rigid substrate or a flexible substrate. The thickness of the substrate 110 can be appropriately selected.

As the material of the substrate 110, for example, resin and ceramics can be used. Examples of the resin include phenol resin, epoxy resin, polyimide resin, bismaleimide triazine resin (BT resin), polyphthalamide (PPA), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and the like. Examples of ceramics include alumina, mullite, forsterite, glass ceramics, nitrides (eg, AlN), carbides (eg, SiC), LTCC (Low Temperature Co-fired Ceramics), and the like. From the viewpoint of low cost and ease of molding, it is advantageous to select a resin as the material of the substrate 110, while ceramics have characteristics of excellent heat resistance and light resistance.

The substrate 110 may be formed of a composite material, and for example, the above resin may be mixed with an inorganic filler such as glass fiber, SiO ₂ , TiO ₂ , or Al ₂ O ₃ . By mixing the filler, effects such as improvement of mechanical strength of the substrate 110, reduction of thermal expansion coefficient, and improvement of light reflectance can be obtained. For example, glass fiber reinforced resin (glass epoxy resin) or the like may be used as the material of the substrate 110.

[Light emitting element 120]
As the light emitting element 120, a known semiconductor light emitting element such as a semiconductor laser or an LED can be used. In this embodiment, an LED is exemplified as the light emitting element 120.

The light emitting element 120 has an upper surface 120a. The light emitting element 120 includes, for example, a transparent substrate, a semiconductor laminated structure on the transparent substrate, an n-side electrode, and a p-side electrode. The semiconductor laminated structure includes an active layer and n-type semiconductor layers and p-type semiconductor layers sandwiching the active layer. The semiconductor laminated structure may include a light emitting capable nitride semiconductor of ultraviolet to visible range _{(In x Al y Ga 1-} xy N, 0 ≦ x, 0 ≦ y, x + y ≦ 1). The n-side electrode is electrically connected to the n-type semiconductor layer, and the p-side electrode is electrically connected to the p-type semiconductor layer. In this example, the n-side electrode and the p-side electrode are located on the side opposite to the upper surface 120a.

As schematically shown in FIG. 2, the light emitting element 120 of each light emitting portion CP is electrically connected and fixed to the wiring layer 140 provided on the substrate 110 by the bonding member 160. That is, here, the light emitting element 120 of each light emitting portion CP is mounted on the substrate 110 by flip chip bonding. Typical examples of the material of the joining member 160 are Au-containing alloy, Ag-containing alloy, Pd-containing alloy, In-containing alloy, Pb-Pd-containing alloy, Au-Ga-containing alloy, Au-Sn-containing alloy, Sn-containing alloy, Sn-. It is a Cu-containing alloy, Sn-Cu-Ag-containing alloy, Au-Ge-containing alloy, Au-Si-containing alloy, Al-containing alloy, Cu-In-containing alloy, or a mixture of metal and flux.

Each light emitting element 120 may be in the form of being sealed with resin, or may be in the form of a bare chip. The light emitting element 120 may have a reflective layer such as a dielectric multilayer film or a metal film on the upper surface 120a. Further, the light emitting element 120 may have a lens or the like that expands the range of the emission angle of the light emitted from the upper surface 120a. It is advantageous that the light emitting element 120 has a bat wing type light distribution characteristic. Here, the batwing type light distribution characteristic refers to a light distribution characteristic defined by a light emission intensity distribution in which the light emission intensity is high at an angle where the absolute value of the light distribution angle is larger than 0° with the optical axis as 0°. ..

An arbitrary wavelength can be selected as the wavelength of the light emitted from the light emitting element 120. The wavelengths of emitted light need not be common between the plurality of light emitting elements 120. A plurality of types of LEDs having different colors of emitted light may be mixed and mounted on the substrate 110.

[Sorting member 130]
The partition member 130 typically has a base 130t provided with a plurality of through holes AP. As shown in FIGS. 2 and 3, the light emitting element 120 of each light emitting portion CP is electrically connected to the wiring layer 140 at the position of the through hole AP provided in the base portion 130t of the partition member 130.

The plurality of inclined surfaces 130s described above extend from the base 130t toward the upper side of the substrate 110, and here, the plurality of inclined surfaces 130s each include a plurality of first inclined surfaces extending in the first direction (for example, the x direction in the drawing). The surface 131 and a plurality of second inclined surfaces 132 each extending in the second direction (for example, the y direction in the drawing) are included.

As shown in FIG. 3, each light emitting unit CP includes a set of first inclined surfaces 131 facing each other with the light emitting element 120 interposed therebetween and a set of second inclined surfaces 132 facing each other with the light emitting element 120 interposed therebetween. That is, here, the set of the first inclined surface 131 and the set of the second inclined surface 132 of each light emitting unit CP surrounds the light emitting element 120 in a rectangular shape in a top view. By arranging the set of the first inclined surface 131 and the set of the second inclined surface 132 so as to surround the light emitting element 120, the light emitted from the light emitting element 120 located inside the light emitting section CP is transmitted to the first inclined surface 131. Alternatively, the light can be reflected upward of the substrate 110 at the position of the second inclined surface 132. That is, the light utilization efficiency can be improved.

The partition member 130 is typically formed of a translucent resin such as polycarbonate (PC), PET, polymethylmethacrylate (PMMA), polypropylene (PP), polystyrene (PS). The partitioning member 130 may be provided with a light diffusing function by dispersing a material having a refractive index different from that of the base material in a base material such as resin. For forming the partition member 130, molding using a mold such as injection molding, extrusion molding, compression molding, vacuum molding, pressure molding, press molding, or stereolithography can be applied. For example, by applying vacuum forming to a translucent sheet formed of PET or the like, a shape in which the base 130t and the plurality of inclined surfaces 130s are integrally formed can be obtained. The thickness of the translucent sheet is, for example, in the range of 100 μm or more and 500 μm or less.

As understood from FIG. 2, in this example, the two second inclined surfaces 132 are located between the two light emitting units CP that are adjacent to each other along the first direction. These two second inclined surfaces 132 form a triangular prism-shaped reflecting structure extending in the second direction, that is, the y direction in the drawing. Similarly, two first inclined surfaces 131 are located between two light emitting portions CP adjacent to each other along the second direction, and these first inclined surfaces 131 are also in the first direction, that is, the x direction in the drawing. Forming a triangular prism-shaped reflecting structure extending to the. In the example shown in FIG. 2, the space formed between the set of these two second inclined surfaces 132 extending in the y direction in the figure and the upper surface 110a of the substrate 110 is hollow. However, the present invention is not limited to this example, and the triangular prism shape formed from the two inclined surfaces (the set of the first inclined surface 131 or the set of the second inclined surface 132) may have a solid reflective structure.

In the present embodiment, each of the first inclined surface 131 and the second inclined surface 132 surrounding the light emitting element 120 has one or more first regions and a lower transmittance for light from the light emitting element 120 than the first region. And a second region indicating. In the configuration illustrated in FIGS. 2 and 3, for example, the first inclined surface 131 has two first regions 131a and a second region 131b located between these first regions 131a in the first direction. Similarly, the second inclined surface 132 has two first regions 132a and a second region 132b located between these first regions 132a in the second direction. Arranging a second region having a relatively low transmittance with respect to the light from the light emitting element 120 at a central portion of the first inclined surface 131 in the first direction and at a central portion of the second inclined surface 132 in the second direction. The effect of will be described later.

The second region 131b of the first inclined surface 131 and the second region 132b of the second inclined surface 132 are formed, for example, by a base material such as resin containing a reflective material such as light-reflective particles, or a resin or the like. This is a region where the transmittance of the light from the light emitting element 120 is relatively low in the partition member 130 by applying the composition containing the base material and the reflective material on the surface. The second region 131b and the second region 132b may be formed integrally with the first region 131a and the first region 132a, or by disposing a partially light-reflective film or the like on the inclined surface 130s, It may be provided on the partition member 130.

[Wiring layer 140]
The wiring layer 140 is located between the top surface 110 a of the substrate 110 and the partition member 130, and has a function of supplying a predetermined current to the light emitting element 120 on the substrate 110 by being connected to an external drive circuit or the like. Have. The material of the wiring layer 140 can be appropriately selected according to the material of the substrate 110, the manufacturing method, and the like. When ceramics is used as the material of the substrate 110, for example, a refractory metal such as tungsten or molybdenum that can be simultaneously fired with the ceramics of the substrate 110 can be used as the material of the wiring layer 140. If a glass epoxy resin is used as the material of the substrate 110, it is useful to select a material that is easy to process as the material of the wiring layer 140. For example, a metal layer of copper, nickel, or the like formed by plating, sputtering, vapor deposition, pasting with a press, or the like can be used as the wiring layer 140. By applying printing, photolithography, or the like as a method of forming the wiring layer 140, a metal layer having a predetermined wiring pattern can be formed relatively easily.

The wiring layer 140 may have a multilayer structure. For example, the wiring layer 140 includes a refractory metal pattern formed by the above-described method and a layer containing another metal such as nickel, gold, or silver formed on the pattern by plating, sputtering, vapor deposition, or the like. You may have.

FIG. 4 shows an example of the wiring pattern of the wiring layer 140. FIG. 4 shows an example of a wiring pattern for connecting the light emitting elements 120, which is four times the number shown in FIG. 1, to the driver 210. The driver 210 may be arranged on the substrate 110 or may be arranged on a substrate different from the substrate 110.

In the example shown in FIG. 4, the wiring layer 140 independently connects four groups each including 16 light emitting elements 120 to the driver 210. Focusing on each of the four groups including 16 light emitting elements 120, four series connections of four light emitting elements 120 are connected in parallel. With such a connection, the driver 210 can drive the integrated light emitting device 100 in units of the region DM including the 16 light emitting elements 120. That is, under such a circuit configuration, the local dimming operation can be performed in units of the region DM including the 16 light emitting elements 120. Of course, the connection of the plurality of light emitting elements 120 by the wiring layer 140 is not limited to the example shown in FIG. For example, the wiring layer 140 may connect these light emitting elements 120 so that each light emitting element 120 in the integrated light emitting device 100 can be driven independently.

[Light diffusion sheet 150]
Please refer to FIG. The light diffusion sheet 150 is an optical sheet that is disposed above the partition member 130 so as to face the upper surface 110a of the substrate 110 and the upper surface 120a of the light emitting element 120. In the example shown in FIG. 1, the partition member 130 is interposed between the upper surface 110 a of the substrate 110 and the light diffusion sheet 150. In the present specification, it may be expressed as “opposing”, including an arrangement in which another member is interposed between two members as in this example.

The light diffusion sheet 150 is typically formed of a resin material such as PC, PS, PMMA, polyethylene, etc., which absorbs less visible light. The structure for diffusing light is provided by providing unevenness on the surface of the light diffusing sheet 150 or dispersing a material having a refractive index different from that of the base material in the light diffusing sheet 150. As the light diffusion sheet 150, an optical sheet having a function of diffusing and transmitting incident light can be used without particular limitation. For example, a member commercially available under the name such as a diffuser film can be applied to the light diffusion sheet 150.

In addition to the light diffusion sheet 150, other commercially available optical members for backlight may be used in the integrated light emitting device 100. For example, a wavelength conversion layer, a prism array layer, a reflective polarization layer, or the like may be further interposed between the light diffusion sheet 150 and the liquid crystal panel 200. The wavelength conversion layer includes a wavelength conversion member such as a phosphor or a quantum dot that is excited by light emitted from the light emitting element 120. A surface light source having a desired chromaticity can be obtained depending on the combination of the wavelength of the light emitted from the light emitting element 120 and the wavelength conversion member. The prism array layer is arranged, for example, at a position farther from the light diffusion sheet 150 than the wavelength conversion layer, has a shape in which a plurality of prisms extending in a predetermined direction are arranged, and allows light incident from various directions to pass through the liquid crystal. Refraction is performed in the direction toward the panel 200 (here, the positive direction of z). The reflective polarization layer is disposed, for example, at a position more distant from the light diffusion sheet 150 than the prism array layer, and generally has a polarization axis whose electric field vector matches the transmission axis of a polarizing plate mounted on the backlight side of the liquid crystal panel 200. Polarized light, which is selectively transmitted and whose electric field vector is perpendicular to this direction, is reflected toward the substrate 110 side. A part of the return light from the reflective polarizing layer is reflected again by the prism array layer, the light diffusion sheet 150, the partition member 130, or the like. At this time, the plane of polarization changes, and the component of which the direction of the electric field vector is parallel to the transmission axis of the polarizing plate of the liquid crystal panel 200 enters the liquid crystal panel 200 through the reflective polarizing layer. That is, by providing the reflective polarization layer, the polarization of the light emitted from the light emitting element 120 is aligned, and the effect of improving the brightness can be obtained.

(Suppression of block emission pattern)
Next, the effect of providing regions having different transmittances on the partition member 130 will be described. FIG. 5 shows a plurality of light emitting parts CP of the integrated light emitting device 100 when viewed from the normal direction of the substrate 110.

As described with reference to FIGS. 2 and 3, in the embodiment of the present disclosure, each of the first inclined surface 131 and the second inclined surface 132 of each light emitting unit CP includes one or more first regions and light emitting portions. A second region having a lower transmittance for the light from the element 120 than the first region is included. When focusing on one light emitting part CP, as shown in FIG. 5, the second region 131b of each first inclined surface 131 has a center in the first direction, that is, in the x direction in the drawing when viewed from the upper surface 110a side of the substrate 110. Located in the department. Further, the second region 132b of each second inclined surface 132 is located in the central portion in the second direction, that is, the y direction in the drawing, when viewed from the upper surface 110a side of the substrate 110.

In each light emitting portion CP, a part of the light emitted from the light emitting element 120 enters the liquid crystal panel 200 directly or via the light diffusion sheet 150. Another part of the light emitted from the light emitting element 120 is also repeatedly reflected, for example, between the base portion 130t of the partition member 130 and the light diffusion sheet 150, and finally enters the liquid crystal panel 200. At this time, of the light emitted from the light emitting element 120, the light incident on the first inclined surface 131 or the second inclined surface 132 is reflected by the first inclined surface 131 and the second inclined surface 132 surrounding the light emitting element 120. By functioning as, it is reflected toward the upper side of the substrate 110. Therefore, for example, by selectively turning on the light emitting element 120 in one light emitting section CP of the plurality of light emitting sections CP and turning off the light emitting elements 120 of the other light emitting sections CP, the light emitting surface is, for example, A part of the upper surface of the light diffusion sheet 150 can be selectively made bright.

Here, according to the study by the present inventor, as in the backlight unit described in Patent Document 1, only by disposing the reflecting member so as to surround the LED chip, for example, the shape of the bright region on the upper surface of the diffuser plate is rectangular. May be too close to. For example, in the application of the local dimming operation, it is possible that a certain light emitting area on the printed board is turned on and a plurality of light emitting areas located around the light emitting area is turned off. Under such an operation, a light emitting pattern that is too close to a rectangle on the light emitting surface may disadvantageously display an image in combination with the liquid crystal panel.

For example, complex drive and/or image processing circuits may be required to display a desired high contrast ratio image. In particular, when the number of areas that can be independently turned on and off is relatively small, image processing cannot correct the discontinuous change in brightness between areas, and the image is displayed with natural brightness and contrast. It may not be possible. When a certain light emitting area is isolated and put into a lighting state, the tendency that the bright area on the light emitting surface approaches a rectangle is that the smaller the distance from the reflecting member to the liquid crystal panel is, and the upper surface of the printed circuit board in the reflecting member. The higher the reflectance of the inclined portion (the second reflecting portion in Patent Document 1), the more remarkable it can be.

Further, even when the liquid crystal panel is arranged at a position distant from the reflecting member to some extent, the light emitted from the LED chip is repeatedly reflected between the reflecting member and, for example, the diffuser plate, resulting in an unnecessary block shape. The noise of the light emitting pattern may be observed on the light emitting surface.

FIG. 6 schematically shows a block-shaped light emitting pattern generated on a light emitting surface of a backlight unit of a comparative example having a plurality of light emitting regions partitioned by a reflecting member like the backlight unit described in Patent Document 1. .. FIG. 6 schematically shows the outer appearance of the light emitting surface of the backlight unit when the light emitting section, which is one of the plurality of light emitting areas partitioned by the reflecting member, is turned on.

In the example shown in FIG. 6, not only the portion of the light emitting surface of the backlight unit (for example, the upper surface of the diffusion plate) corresponding to the central light emitting region CP1 where the LED chip is turned on, but also the LED chip is turned off. Even the portions corresponding to the plurality of light emitting areas surrounding the light emitting area CP1 are bright. At this time, a bright portion that appears in a portion that should originally be a dark area on the light emitting surface has a substantially rectangular shape because the reflecting member of each light emitting area surrounds the LED chip in a rectangular shape. Is perceived as block noise by the observer.

FIG. 7 also shows a state of reflection of light emitted from the LED chip of the backlight unit of the comparative example having a reflection member having no light transmission property and a schematic luminance distribution on the light emitting surface. The backlight unit 400 of the comparative example shown in FIG. 7 has a plurality of LED chips 420 arranged on a printed circuit board 410. Further, a reflecting member 430 having a triangular cross section is arranged on the printed circuit board 410 so as to surround the LED chip 420.

In FIG. 7, “H” and “L” schematically show the luminance distribution on the light emitting surface. Specifically, “H” represents an area where the luminance tends to be relatively high on the light emitting surface, and “L” represents an area where the luminance tends to be relatively low on the light emitting surface. .. In this example, as shown by a dotted arrow QL in FIG. 7, light emitted from the LED chip 420 in a certain light emitting region and reflected by the lower surface 450b of the diffusion plate 450 is another light emission adjacent to the light emitting region. It is further reflected by the inclined surface of the reflection member 430 in the region and passes through the diffusion plate 450. Therefore, in the upper surface 450a of the diffusion plate 450, not only the portion centered on the light emitting area including the LED chip 420 drawn in the center of FIG. 7, but also immediately above the reflecting member 430 in the light emitting area adjacent to the light emitting area. The brightness at is also high. As a result, block-like noise as shown in FIG. 6 occurs on the light emitting surface.

By disposing the diffusion plate 450 above the printed circuit board 410 so that the lower surface 450b of the diffusion plate 450 contacts the top of the reflection member 430, the light leaking from the light emitting region where the LED chip 420 is turned on to another light emitting region is reduced. be able to. However, although the luminance of the noise portion is slightly lowered, it is inevitable that the noise generated on the light emitting surface becomes blocky in this case as well. In the case where there is noise in which an unintended portion shines brightly, it is generally difficult to eliminate the influence of noise by image processing if the noise is particularly block-shaped.

The situation in which block-shaped noise is generated on the light emitting surface is, as in the technique described in Patent Document 2 or 3, an area where light is partially transmitted above the triangular prismatic partition member or the light amount correction member (Patent Document 2). The same applies to the case where the second partition wall portion or the first reflection region of Patent Document 3) is provided over all of these members along the direction in which these members extend. Further, even if the diffusion plate 450 is arranged above the printed circuit board 410 so as to be in contact with the top of the partition member or the light amount correction member, the light transmitting region closest to the light emitting region where the LED chip 420 is turned on is light-transmissive. More light is incident through the area. Therefore, in particular, the brightness of the position immediately above the partition member or the light amount correction member in the closest light emitting region becomes large. That is, the block noise appears more clearly on the light emitting surface.

On the other hand, in the embodiment of the present disclosure, the first inclined surface 131 of each light emitting unit CP has the second region 131b whose transmittance is lower than that of the first region 131a, and the second region 131b. 131b is located at the center of the first inclined surface 131 in the first direction when viewed from the upper surface 110a side of the substrate 110. In addition, the second inclined surface 132 of each light emitting unit CP has a second region 132b whose transmittance is lower than that of the first region 132a, and the second region 132b is on the upper surface 110a side of the substrate 110. It is located at the central portion of the second inclined surface 132 in the second direction when viewed from above. In other words, the second regions 131b and 132b having a low transmittance are located in regions of the plurality of inclined surfaces 130s that partition the light emitting unit CP that are relatively small in distance from the light emitting element 120. Therefore, it is possible to reduce the leakage of light to the light emitting unit CP closest to the light emitting unit CP and reflect more light toward the upper side of the substrate 110 at the positions of the second regions 131b and 132b.

Further, in the embodiment of the present disclosure, in the four corners of each of the rectangular light-emitting portions CP in a top view, for example, as shown in FIG. 5, for example, the first region 131a of the first inclined surface 131 or the second inclination is formed. The first area 132a of the surface 132 is located. The first regions 131a and 132a can transmit a larger part of the incident light as compared with the second region 131b or 132b. That is, the partitioning member 130 has a direction different from the first direction and the second direction (in the example of FIG. 5, in the plane of the integrated light emitting device 100) as schematically shown by a thick dotted arrow LR in FIG. It is possible to allow appropriate light leakage in the diagonal direction. As a result, the generation of block noise due to the leakage of light between the light emitting portions CP is mitigated, and the shape of the bright portion can be approximated to a circle. Therefore, according to the embodiments of the present disclosure, it is possible to advantageously apply the local dimming operation to display a natural image with a high contrast ratio while avoiding complication of the drive circuit.

The specific configurations of the second region 131b of the first inclined surface 131 and the second region 132b of the second inclined surface 132 are not limited to a specific configuration. For example, when the partitioning member 130 contains a base material and particles of a reflective material having a refractive index different from that of the base material, the central portion of the first inclined surface 131 in the first direction and the second inclined surface 132 of the first inclined surface 131. The second region 131b and the second region 132b may be formed by selectively increasing the number density of particles in the central portion in the two directions. As the particles of the reflecting material, for example, oxide particles of titanium oxide, aluminum oxide, silicon oxide or the like can be used.

For example, when the shape of the partition member 130 is formed from a light-transmitting sheet, unevenness is partially provided on the first inclined surface 131 and the second inclined surface 132 by surface texturing or the like, or the shape of the partition member 130 is obtained. After sandblasting, it may be carried out. Thereby, the haze value of a part of the first inclined surface 131 and the second inclined surface 132 can be increased, for example, as compared with other parts. When the haze value of a part of the first inclined surface 131 and the second inclined surface 132 is increased when the shape of the partition member 130 is obtained by cutting out from the bulk, the second region 131b and the second region 132b are formed. It may be formed.

Alternatively, like the partitioning member 130A illustrated in FIG. 8, light is reflected on the surface of the partitioning member 130A at the central portion of the first inclined surface 131 in the first direction and the central portion of the second inclined surface 132 in the second direction. The second region 131b and the second region 132b may be formed by disposing the member 134. By disposing the light reflection member 134 on the inclined surface 130s, the reflectances of the first inclined surface 131 and the second inclined surface 132 as the light reflection surface are partially improved, so that the second region 131b and the second region 132b. It is possible to relatively reduce the transmittance.

As the light reflecting member 134, a film of silver, gold, aluminum, or an alloy containing one or more of these can be used. A dielectric multilayer film or the like may be used as the light reflecting member 134. For forming the light reflecting member 134, vapor deposition, plating, coating, etc. may be applied without particular limitation. The second region 131b and the second region 132b may have a specular reflection surface or a diffuse reflection surface. As the light reflecting member 134, a semi-transmissive dichroic film exhibiting a metallic luster, or a light diffusing sheet cut out in a predetermined shape, which is commercially available from Toray Industries, Inc. under the name of "PICASSUS (registered trademark)". A sheet piece or the like may be used.

A typical example of the arrangement of the second region 131b on the first inclined surface 131 and the second region 132b on the second inclined surface 132 will be described with reference to FIG. 5 again. In FIG. 5, a distance from the second region 131b or the second region 132b of the light emitting unit CP to the light emitting element 120 is indicated by a thin solid arrow Ds. At this time, when the minimum value of the distance Ds from the second region 131b or the second region 132b to the light emitting element 120 is D, the second region 131b of the first inclined surface 131 of each light emitting unit CP has the first inclined surface 131. The distance Ds is provided in a region where the distance Ds is, for example, 100% or more and 120% or less of the minimum value D. Similarly, the second region 132b of the second inclined surface 132 of each light emitting unit CP is provided in the region of the second inclined surface 132 where the distance Ds is, for example, 100% or more and 120% or less of the minimum value D.

However, the range of the second region 131b of the first inclined surface 131 and the range of the second region 131b of the second inclined surface 132 are the specifications of the light emitting element 120 and the arrangement of the plurality of light emitting units CP. It can be appropriately determined according to the above. The arrangement pitch of the light emitting elements 120, that is, the distance between the centers of the light emitting elements 120 adjacent to each other may be, for example, in the range of 0.1 mm or more and less than 5 mm. The arrangement pitch of the light emitting elements 120 in the first direction and the arrangement pitch in the second direction may be equal to or different from each other.

FIG. 9 shows another example of the arrangement of the first region 131a on the first inclined surface 131 and the first region 132a on the second inclined surface 132. In the examples described so far, each of the two first inclined surfaces 131 defining each light emitting unit CP is located between the two first regions 131a and the first regions 131a in the first direction. It has two second regions 131b. Further, each of the two second inclined surfaces 132 that define each light emitting unit CP also has two first regions 132a and one second region 132b located between these first regions 132a in the second direction. Have

Similar to the examples described so far, in the configuration illustrated in FIG. 9 as well, the partitioning member 130B includes a set of first inclined surfaces 131 and a set of second inclined surfaces 132 that define the light emitting portion CP. However, in this example, each first inclined surface 131 includes one first area 131a and one second area 131b, and each second inclined surface 132 includes one first area 132a and one second area 131a. The second region 132b is included.

Also in the example shown in FIG. 9, the points where the second region 131b and the second region 132b are respectively located at the central portion of the first inclined surface 131 in the first direction and the central portion of the second inclined surface 132 in the second direction are The same as the examples described so far. As shown in the figure, here, the portions of the first region 131a of the first inclined surface 131 located on the left and right of the second region 131b are connected to each other near the base 130t of the partition member 130B. Similarly, portions of the first region 132a of the second inclined surface 132 located on the left and right of the second region 132b are connected to each other near the base 130t of the partition member 130B. In the embodiment of the present disclosure, it is not essential to provide each of the first inclined surface 131 and each of the second inclined surfaces 132 with two first regions.

FIG. 10 illustrates a modification of the integrated light emitting device according to the embodiment of the present disclosure. The integrated light emitting device 100A shown in FIG. 10 further includes a reflective layer 171 located between the base 130t of the partition member 130 and the wiring layer 140. As illustrated in FIG. 10, by disposing the reflection layer 171 between the partition member 130 and the wiring layer 140, light directed toward the upper surface 110 a of the substrate 110 is directed in the direction opposite to the substrate 110, that is, above the substrate 110. Since it can be reflected toward, it is possible to improve the light utilization efficiency.

For example, epoxy resin, urethane resin, acrylic resin, polycarbonate resin, polyimide resin, oxetane resin, silicone resin, modified silicone resin, and other base materials, titanium oxide, aluminum oxide, a resin in which oxide particles such as silicon oxide are dispersed A layer can be applied to the reflective layer 171. The reflective layer 171 may have a reflectance of 70% or more with respect to the light from the light emitting element 120. A resist layer formed on the wiring layer 140 may be used as the reflective layer 171.

FIG. 11 illustrates another modification of the integrated light emitting device according to the embodiment of the present disclosure. The integrated light emitting device 100B illustrated in FIG. 11 includes a partition member 130C, and the partition member 130C further includes a reflective layer 172 located on the base 130t. By arranging the reflection layer 172 on the base 130t, the effect of improving the light utilization efficiency can be expected, as in the case where the reflection layer 171 is arranged between the partition member 130 and the wiring layer 140. As the reflective layer 172, for example, a resin layer similar to the above-described reflective layer 171 can be applied. As the reflection layer 172, a metal or alloy film, a dielectric multilayer film, or the like may be applied.

The integrated light emitting device according to the embodiment of the present disclosure can be used as a surface light emitting device, and can be used, for example, in a backlight of a liquid crystal display device, various illumination light sources, vehicle light sources, and the like. Embodiments of the present disclosure are particularly advantageous for local dimming operation applications.

100, 100A, 100B Integrated light emitting device 110 Substrate 120 Light emitting element 130, 130A to 130C Sorting member 130s Sloping surface of sorting member 130t Base of sorting member 131 First slanted surface of sorting member 131a First region of first slanting surface 131b Second region 132 of first inclined surface 132 Second inclined surface of partition member 132a First region of second inclined surface 132b Second region of second inclined surface 134 Light reflection member 140 Wiring layer 150 Light diffusion sheet 171, 172 Reflection layer 200 liquid crystal panel 300 liquid crystal display device CP light emitting unit

Claims (8)

A substrate having an upper surface,
A plurality of light emitting elements two-dimensionally arranged on the upper surface side of the substrate along a first direction and a second direction orthogonal to the first direction;
A translucent partitioning member that is located on the upper surface side of the substrate and has a plurality of inclined surfaces, wherein the plurality of inclined surfaces each include a plurality of first inclined surfaces extending in the first direction, and Partitioning members each including a plurality of second inclined surfaces extending in the second direction;
A wiring layer located between the upper surface of the substrate and the partition member and electrically connected to the plurality of light emitting elements;
A plurality of light emitting units each including one of the plurality of light emitting elements and a set of the first inclined surface and a set of the second inclined surface that surrounds the one light emitting element in a rectangular shape in a top view. Have,
Each of the first inclined surface and each of the second inclined surface included in each light emitting unit exhibits one or more first regions and a lower transmittance for light from the light emitting element than the one or more first regions. And a second region,
The second region of each first inclined surface included in each light emitting unit is located at a central portion in the first direction when viewed from the upper surface side of the substrate,
The integrated light emitting device, wherein the second region of each second inclined surface included in each light emitting unit is located at a central portion in the second direction when viewed from the upper surface side of the substrate. The one or more first regions include two first regions,
The second region of each first inclined surface included in each light emitting unit is located between the two first regions in the first direction,
The integrated light emitting device according to claim 1, wherein the second region of each second inclined surface included in each light emitting unit is located between the two first regions in the second direction. The integrated light emitting device according to claim 1, wherein the plurality of inclined surfaces have a light reflecting member arranged in each second region. The partition member has a base portion provided with a plurality of through holes,
The integrated light emitting device according to claim 1, wherein the plurality of light emitting elements are electrically connected to the wiring layer at positions of the plurality of through holes in a top view. The integrated light emitting device according to claim 4, further comprising a reflective layer disposed between the base portion of the partition member and the wiring layer. The integrated light emitting device according to claim 4, wherein the partition member has a second light reflecting member on the base portion. The integrated light emitting device according to claim 1, further comprising a light diffusion sheet that is located above the partition member and faces the upper surface of the substrate. When the minimum value of the distance from the one light emitting element to the first inclined surface or the second inclined surface in each light emitting unit is D,
Each second region of each light emitting portion is arranged in a region of the first inclined surface and the second inclined surface, the distance from the light emitting element being in the range of 100% or more and 120% or less of D. The integrated light emitting device according to claim 1.

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