JP2016213365A - Light emitting device, display device, and manufacturing method of light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device which prevents all external light from being reflected in the same direction when the external light enters into the light emitting device, and to provide a display device which makes the visibility of images less likely to deteriorate even when the external light enters into a display screen.SOLUTION: A light emitting device 10 includes: an element substrate 11 having a surface which is formed in a dark color; light sources 12r, 12g, 12b disposed on the surface of the element substrate 11; and a sealing part 13 which is disposed on the element substrate 11 so as to cover the light sources 12r, 12g, 12b and includes a boarder surface 13a which is a border with an exterior part and a convex curved surface expanding in a direction facing the element substrate 11.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a light emitting device, a display device including the light emitting device, and a method for manufacturing the light emitting device.

  Display devices are used in various places to provide information, whether indoors or outdoors. The display device generally constitutes a display screen by arranging a plurality of light emitting devices in a matrix form in the vertical and horizontal directions. The display device displays characters, figures, and other images that are visible to the user on the display screen by changing the luminance and emission color of each light-emitting device in accordance with an externally input signal.

  As a light emitting device of a display device, an SMD (surface mount device) configured by mounting a light source such as an LED (light emitting diode) on an element substrate and sealing with a transparent resin so as to cover the light source. : Surface mount device) type light emitting devices are often used. The light emitted from the light source of the light emitting device is transmitted through the transparent resin and emitted to the outside. In the SMD type light emitting device, since the boundary surface where the transparent resin is in contact with the external space is formed flat, a wide viewing angle can be realized (for example, Patent Document 1).

JP 2015-26871 A

  When the display device is installed outdoors such as a wall surface of a sports facility or a commercial facility, external light such as sunlight or external illumination light may enter the display device and be reflected on the display screen of the display device. When the external light is reflected on the display screen in this way, the light emission of the light emitting device is buried in the reflected light, so that the contrast of the image displayed on the display screen is reduced, and the user visually recognizes the image on the display screen. It becomes difficult. Such an event may be caused by external light such as indoor illumination light even when the display device is installed indoors.

  In particular, when a display device is configured using an SMD type light emitting device as in Patent Document 1, the boundary surface with the outer space in the sealing portion of the light emitting device is formed flat, so that the light is incident in parallel. All external light is reflected in the same direction. When the user is in the direction in which the external light is reflected, all the reflected light is incident on the user's eyes, so the light emission of the light emitting device is buried in the reflected light, and the contrast of the image is significantly reduced. Further, in order to improve the luminous efficiency of normal LEDs, a reflective material is disposed around the LED chip, and the contrast is also reduced by external light reflection by the reflective material.

  In recent years, the resolution of display devices has been increasing, and the number of light emitting devices per unit area has increased. For this reason, the characteristic of the reflected light reflected by the boundary surface of the sealing part provided in the light emitting device has a great influence on the contrast of the image on the display screen.

  The present invention has been made based on such a background, and an object thereof is to provide a light emitting device in which all external light is not reflected in the same direction when external light is incident on the light emitting device. To do. It is another object of the present invention to provide a display device in which the visibility of an image on the display screen is unlikely to deteriorate even when external light is incident on the display screen.

  In order to achieve the above object, a light-emitting device according to the present invention includes an element substrate, a light source disposed on the surface of the element substrate, an element substrate so as to cover the light source, and a boundary surface with the outside. And a sealing portion that is a convex curved surface that swells in a direction facing the element substrate, and the surface of the element substrate is formed in a dark color.

  According to the present invention, the external light incident on the light emitting device is reflected by the convex curved surface formed on the boundary surface of the sealing portion and diverges in various directions. Therefore, the light emission of the light emitting device is not buried in the reflected light, and a decrease in image contrast in the display device can be suppressed.

It is a side view of the light-emitting device which concerns on Embodiment 1 of this invention. It is a front view of the light-emitting device which concerns on Embodiment 1 of this invention. It is sectional drawing which looked at the light-emitting device shown in FIG. 2 by the AA line. It is a front view of the display apparatus which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the reflected light of the light-emitting device which concerns on Embodiment 1 of this invention. It is a side view of the light-emitting device which concerns on Embodiment 2 of this invention. It is sectional drawing which looked at the light-emitting device which concerns on Embodiment 2 of this invention by the AA line of FIG. 2 similarly to FIG. It is a front view of the display apparatus which concerns on Embodiment 2 of this invention. It is a side view of the display apparatus which concerns on Embodiment 2 of this invention. It is a schematic diagram which shows the reflected light of the display apparatus which concerns on Embodiment 2 of this invention.

  Hereinafter, embodiments of a light emitting device and a display device according to the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals are given to the same or equivalent parts.

  In the embodiment of the light emitting device and the display device according to the present invention, the dark color refers to a color obtained by performing a process of reducing the reflectance (hereinafter simply referred to as “reflectance”) and lightness to sunlight. . This dark color includes black. For example, a material containing a colorant having a reflectance and brightness lower than that of the base is formed on the base, or a base material containing a colorant having a reflectance and brightness lower than that of the base material. By forming the element substrate, a dark surface can be realized. Specifically, examples of the dark color include, in addition to black, gray, dark blue, dark brown, dark purple, dark blue, dark green, and the like. The dark color may be an achromatic color or a chromatic color. As a result of the visual test, the dark color is preferably a color with a brightness of 4 or less in the Munsell color system, and more preferably 2 or less. As a result of the visual test, the dark color reflectance is preferably 30% or less, and more preferably 20% or less.

  Note that in the embodiment of the light emitting device and the display device according to the present invention, the external light is light emitted outside the display device. The external light includes not only light emitted outdoors such as sunlight and external illumination light but also light emitted indoors such as internal illumination light.

(Embodiment 1)
With reference to FIGS. 1-5, the light-emitting device 10 and the display apparatus 20 which concern on Embodiment 1 of this invention are demonstrated.

  As shown in FIGS. 1 and 2, the light emitting device 10 is mounted on an element substrate 11 and a mounting surface 11 a of the element substrate 11, and three LED chips 12 r and 12 g that emit red light, green light, and blue light, respectively. , 12b and a sealing portion 13 which is disposed on the element substrate 11 so as to cover the LED chips 12r, 12g and 12b and seals the LED chips 12r, 12g and 12b with the element substrate 11.

  The light emission intensities of the three LED chips 12r, 12g, and 12b are independently adjusted by electric power supplied from a drive IC (not shown) via the wiring of the element substrate 11 described in detail below. Thereby, the light-emitting device 10 can emit light of an arbitrary color with an arbitrary intensity. The three LED chips 12r, 12g, and 12b are arranged in the order of LED chips that emit red light, green light, and blue light from the left side as shown in FIGS. 1 and 2, but can be arranged in an appropriate order. It is. Further, the three LED chips 12r, 12g, and 12b may be arranged in a direction perpendicular to the element substrate 11 instead of being arranged in the horizontal direction on the element substrate 11.

  As shown in FIGS. 1 to 3, the element substrate 11 is made of an insulating material, and wirings 14 r and 15 r for supplying power to the LED chip 12 r are mounted on the mounting surface 11 a on which the LED chips 12 r, 12 g and 12 b are mounted. Wirings 14g and 15g for supplying power to the LED chip 12g and wirings 14b and 15b for supplying power to the LED chip 12b are provided. The wiring 14r and the wiring 15r are electrically connected to the cathode electrode and the anode electrode of the LED chip 12r through the bonding wires 16, respectively. Similarly to the LED chip 12r and the wirings 14r and 15r, the wirings 14g and 15g are electrically connected to the cathode electrode and the anode electrode of the LED chip 12g through the bonding wires 16, respectively, and the wirings 14b and 15b are connected. Is also electrically connected to the cathode electrode and the anode electrode of the LED chip 12b via the bonding wire 16.

  The light emitting device 10 according to the first embodiment may be configured such that a member that blocks light emitted from the LED chips 12r, 12g, and 12b does not exist around the boundary surface 13a of the sealing portion 13. In such a configuration, light rays from the LED chips 12r, 12g, and 12b can be emitted not only in a direction perpendicular to the element substrate 11 but also in a direction substantially horizontal to the element substrate 11, and thus a wide viewing angle can be realized.

  The sealing part 13 is comprised from translucent resin materials, such as an epoxy resin, a polyester resin, and an acrylic resin. The sealing part 13 contains LED chip 12r, 12g, 12b and the bonding wire 16, and is closely_contact | adhered to these. The sealing portion 13 is in close contact with the mounting surface 11a of the element substrate 11 and the wirings 14r, 15r, 14g, 15g, 14b, and 15b. Since the sealing part 13 should just have translucency, it may be formed from a transparent material or may be formed from a translucent material. Further, the sealing portion 13 is not limited to a resin material, and may be made of a glass material.

  As shown in FIGS. 1 and 3, the sealing portion 13 swells toward the side facing the element substrate 11, and the boundary surface 13 a with the space outside the sealing portion 13 forms a convex lens-like curved surface. doing. The sealing portion 13 is disposed so that the central axis C, which is an axis perpendicular to the element substrate 11, is coaxial with the optical axis L of the LED chip 12g. The boundary surface 13a of the sealing portion 13 is farthest from the mounting surface 11a of the element substrate 11 at the intersection P between the optical axis L (center axis C) of the LED chip 12g and the boundary surface 13a. Further, the boundary surface 13 a of the sealing portion 13 is curved so as to approach the mounting surface 11 a of the element substrate 11 as it moves away from the intersection point P in the direction parallel to the element substrate 11.

  And as shown in FIG. 4, the display apparatus 20 which has a display screen is comprised by arrange | positioning many such light-emitting devices 10 in the matrix form to the vertical direction and a horizontal direction.

  The light emitting device 10 of the first embodiment is manufactured by the following process. First, the LED chips 12r, 12g, and 12b are arranged on the element substrate 11 provided with the wirings 14r, 15r, 14g, 15g, 14b, and 15b. Next, the wires 14 r and 15 r of the element substrate 11 are electrically connected to the cathode electrode and the anode electrode of the LED chip 12 r by the bonding wires 16. Similarly to the LED chip 12r and the wirings 14r and 15r, the wirings 14g and 15g of the element substrate 11 are electrically connected by the bonding wires 16 to the cathode electrode and the anode electrode of the LED chip 12g, and the cathode of the LED chip 12b. Wirings 14 b and 15 b of the element substrate 11 are electrically connected to the electrodes and the anode electrode by bonding wires 16. Thereafter, the LED chips 12r, 12g, and 12b mounted on the element substrate 11 are encapsulated in the concave portion of the molding die in which the concave curved surface corresponding to the convex curved surface formed on the boundary surface 13a of the sealing portion 13 is formed. Arrange as follows. Then, when a liquid resin material is injected into the concave portion of the mold and the resin material is cured, the sealing portion 13 whose boundary surface 13a with the outside is a convex curved surface is formed on the element substrate 11.

  The operation of the light emitting device 10 according to the first embodiment will be described. As shown in FIG. 5, in the light emitting device 10 according to the first embodiment, even if the external light R1 is incident on all the regions of the boundary surface 13a of the sealing portion 13 in parallel, the boundary surface 13a of the sealing portion 13 Is formed in a convex curved surface that swells in a direction facing the element substrate 11, the reflected light R2 diverges. For this reason, if the display device 20 is configured by arranging a large number of light emitting devices 10 according to the first embodiment in a matrix in the vertical and horizontal directions, the light emitted from the display device 20 is buried in the reflected light R2. Therefore, a decrease in image contrast can be effectively suppressed.

  Further, in the light emitting device 10 according to the first embodiment, the member that blocks the light emitted from the LED chips 12r, 12g, and 12b does not exist around the boundary surface 13a of the sealing portion 13, and therefore the LED chips 12r, 12g, and 12b. Can be emitted not only in a direction perpendicular to the element substrate 11 but also in a direction substantially horizontal to the element substrate 11. For this reason, even when the user views the display screen of the display device 20 from an angle deviated from the front, it is possible to suppress a decrease in the contrast of the image.

  And since the light-emitting device 10 of Embodiment 1 forms the sealing part 13 by pouring a liquid resin material with respect to a shaping | molding die and making it harden | cure, the boundary surface 13a of the sealing part 13 is made into a convex curve. It is easy to form. For this reason, the light-emitting device 10 whose boundary surface 13a of the sealing part 13 is a convex curve can be manufactured efficiently, and manufacturing cost can be reduced.

(Embodiment 2)
With reference to FIGS. 6-10, the light-emitting device 30 and the display apparatus 40 which concern on Embodiment 2 of this invention are demonstrated.

  In the first embodiment, the display device 20 is configured by arranging the light emitting devices 10 in a matrix, but in the second embodiment, the light emitting device 30 is mounted on the mounting surface 41a of the circuit board 41 with a gap. The display device 40 is configured by disposing the louver 42 in a gap provided between the adjacent light emitting devices 30. The display device 40 of the second embodiment is different from the display device 20 of the first embodiment in that it has the above-described configuration, but the other configurations are the same. Therefore, the same members are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 6, the light emitting device 30 according to the second embodiment includes an element substrate 31, three LED chips 12r, 12g, and 12b mounted on the element substrate 31, and LED chips 12r, 12g, and 12b. The sealing part 13 sealed on the element substrate 31 is provided.

  As shown in FIGS. 6 and 7, the element substrate 31 may have a size that allows the three LED chips 12r, 12g, and 12b to be mounted on the mounting surface 31a. Similar to the element substrate 11 in the first embodiment, the element substrate 31 is provided with wirings 14r, 15r, 14g, 15g, 14b, and 15b on the mounting surface on which the LED chips 12r, 12g, and 12b are mounted.

  As shown in FIG. 7, the element substrate 31 has wirings 14r, 15r, 14g, 15g, 14b, 15b on the surface facing the mounting surface 31a through the through holes 32 provided in the element substrate 31, respectively. And six electrodes 33 that are electrically connected to each other. Each of the six electrodes 33 is also electrically connected to the wiring of the circuit board 41. Therefore, the LED chips 12r, 12g, and 12b are connected to the circuit board 41 via the wiring (not shown) of the circuit board 41, the electrode 33, the wirings 14r, 15r, 14g, 15g, 14b, and 15b, and the bonding wire 16, respectively. The drive IC (not shown) is electrically connected.

  In the light emitting device 30 according to the second embodiment, as in the light emitting device 10 according to the first embodiment, three LED chips 12r, 12g, and 12b are mounted on the mounting surface 31a of the element substrate 31, and the LED chips 12r, 12g, and 12b are mounted. The mounting surface 31a is covered with a sealing portion 13 having translucency. As described above, the sealing portion 13 may be configured such that the boundary surface 13a with the outside is a convex curved surface.

  As shown in FIG. 8, a plurality of light emitting devices 30 configured as described above are arranged in a matrix in the vertical and horizontal directions while being spaced from each other on the mounting surface 41a of the circuit board 41, thereby displaying the display device. 40 is configured.

  As shown in FIGS. 8 and 9, a louver 42 for diffusing the external light R <b> 1 is provided so as to cover the gap formed between the adjacent light emitting devices 30 on the circuit board 41. By installing the louver 42 between the adjacent light emitting devices 30, the reflected light R2 can be diffused not only in the boundary surface 13a of the sealing portion 13 in the light emitting device 30 but also in the region where the light emitting device 30 does not exist. become. For this reason, it is possible to further improve the contrast of the image on the display screen as compared with the display device 20 of the first embodiment.

  Surface treatment for scattering the reflected light R2 on the surface 42a of the louver 42 may be performed so that the reflected light R2 from the surface 42a of the louver 42 is effectively diffused. As a surface treatment for scattering the reflected light R2, the surface 42a of the louver 42 may be coated to diffuse the external light R1. In order to obtain a paint suitable for coating that diffuses the external light R1, it is conceivable to mix fine particles in the paint. By applying such paint to the surface 42a of the louver 42, irregularities can be formed on the surface 42a of the louver 42, and the reflected light R2 can be effectively scattered.

  Further, as the surface processing for scattering the reflected light R2, the surface 42a of the louver 42 may be textured. Since the unevenness is provided on the surface 42a of the louver 42 by the texture processing, the reflected light R2 can be diffused more effectively. These surface treatments may be performed not on the entire surface 42 a of the louver 42 but only on a part of the surface 42 a of the louver 42.

  The louver 42 according to the second embodiment may have a structure that blocks external light R1 from entering the light emitting device 30 and the circuit board 41. Instead of scattering the reflected light R2 by the louver 42, the louver 42 may be made of a black matrix material so as to absorb the external light R1.

  The operation of the light emitting device 30 and the display device 40 of the second embodiment will be described. As shown in FIG. 10, the display device 40 according to the second embodiment has the light emitting device 30 in which the LED chips 12r, 12g, and 12b are mounted on the mounting surface 31a of the element substrate 31 mounted on the mounting surface 41a of the circuit board 41. Since the louver 42 is arranged between the adjacent light emitting devices 30, not only the boundary surface 13 a of the sealing portion 13 of the light emitting device 30 but also the surface 42 a of the louver 42 arranged between the light emitting devices 30. Also, the reflected light R2 can be diffused. For this reason, since it becomes possible to diffuse the reflected light R2 over the entire display device 40, it is possible to suppress a decrease in the contrast of the image when the display device 40 is viewed from any direction. Can be improved.

(Embodiment 3)
A feature of the light emitting device of the third embodiment is that a diffusion layer 13b is provided on the boundary surface 13a of the sealing portion 13 of the first and second embodiments. The light emitting device of the third embodiment is different from the light emitting devices 10 and 30 of the first and second embodiments in that it has the above configuration, but the other configurations are the same. Accordingly, the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  In the light emitting device of Embodiment 3, the diffusion layer 13b is provided on the boundary surface 13a of the sealing portion 13, and the reflected light R2 is diffused by the diffusion layer 13b. The sealing portion 13 of the third embodiment is similar to the sealing portion 13 of the first and second embodiments, in addition to the boundary surface 13a being formed in a convex curved surface, Since the diffusion layer 13b is provided on the boundary surface 13a, the reflected light R2 can be more effectively scattered. For this reason, the display device according to the third embodiment can further suppress the reduction in the contrast of the image than the display devices 20 and 40 according to the first and second embodiments.

(Modification)
The above embodiment is an example of a specific embodiment of the present invention, and the technical scope of the present invention is not limited by the description of the above embodiment. The present invention can be freely modified or improved within the scope of the technical idea shown in the claims. In addition, it is optional to add components that are not disclosed in the above embodiment.

  In the said embodiment, although the number of LED chips 12r, 12g, and 12b with which the light-emitting devices 10 and 30 are provided is three, the number of LED chips is not limited to three. One or two may be sufficient, and four or more may be sufficient. Moreover, the light emission color of the light-emitting devices 10 and 30 is not limited. The combination of luminescent colors is arbitrary.

  In the above embodiment, the central axis C of the sealing portion 13 and the optical axis L of the LED chip 12g are arranged coaxially, but the optical axis L of the LED chip 12g is shifted from the central axis C of the sealing portion 13. You may arrange in. In the above embodiment, the convex curved surface provided on the boundary surface 13a of the sealing portion 13 is a convex lens-shaped three-dimensional curved surface. However, the convex curved surface is not limited to a three-dimensional curved surface and is not a two-dimensional curved surface. It may be a spherical surface.

  In the said embodiment, although the manufacturing method which has the process of forming the sealing part 13 by shaping | molding using a shaping | molding die was shown as an example, the manufacturing method of the sealing part 13 is not limited to this. For example, the sealing portion manufactured in another process may be fitted into the element substrates 11 and 31 so as to cover the light emitting devices 10 and 30.

  In manufacturing the light emitting devices 10 and 30, an additional member having a convex curved surface may be provided on the upper surface of the sealing portion 13 after finishing the upper surface of the sealing portion 13 to be flat. Alternatively, an additional member molded in advance may be placed on the upper surface of the sealing portion 13 and attached by adhesion or the like.

  The additional member may be formed by dripping and curing a liquid resin material little by little so as to form a convex curved surface on the upper surface of the sealing portion 13. The sealing portion 13 may be covered with a molding die, and an additional member may be formed by injecting a liquid resin material into the molding die.

10, 30 Light-emitting device, 11, 31 Element substrate, 11a, 31a, 41a Mounting surface, 12r LED chip, 12g LED chip, 12b LED chip, 13 Sealing portion, 13a Boundary surface, 13b Diffusion layer, 14r, 14g, 14b , 15r, 15g, 15b wiring, 16 bonding wire, 20, 40 display device, 32 through-hole, 33 electrode, 41 circuit board, 42 louver, 42a surface, C central axis, L optical axis, P intersection, R1 external light, R2 reflected light

Claims (7)

An element substrate having a dark surface, and
A light source disposed on the surface of the element substrate;
A sealing portion that is disposed on the element substrate so as to cover the light source, and is a convex curved surface in which a boundary surface with the outside swells in a direction facing the element substrate;
A light emitting device comprising: The sealing portion is molded by a molding die having a concave curved surface corresponding to the shape of the boundary surface.
The light emitting device according to claim 1. A diffusion layer for diffusing light is provided on the boundary surface of the sealing portion.
The light emitting device according to claim 1. The light emitting device according to any one of claims 1 to 3,
A circuit board on which a plurality of the light emitting devices are arranged at intervals;
A louver disposed between the light emitting devices adjacent to each other;
A display device comprising: The display device according to claim 4, wherein the surface of the louver is subjected to surface processing for diffusing light. The display device according to claim 5, wherein the surface processing is painting or embossing for diffusing light. Attaching a light source to the element substrate;
Arranging the light source attached to the element substrate so as to be enclosed in a concave portion of a mold having a concave curved surface;
Injecting a liquid resin material into the recess and curing the resin material;
A method for manufacturing a light-emitting device including:

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