CN111856813A

CN111856813A - Area light source module for backlight device

Info

Publication number: CN111856813A
Application number: CN201910935150.4A
Authority: CN
Inventors: 河枝锡
Original assignee: Heesung Electronics Co Ltd
Current assignee: Heesung Electronics Co Ltd
Priority date: 2019-04-30
Filing date: 2019-09-29
Publication date: 2020-10-30
Also published as: WO2020222359A1; KR20200127083A; TW202041935A

Abstract

The present invention relates to an LED module for backlight of a display device which can be applied to a highly transparent substrate to simplify the structure and manufacturing process, the surface light source module of the present embodiment includes: a substrate printed with a circuit; a casting part which provides a plurality of cavities and is combined on the substrate; a light emitting element mounted on the substrate inside the cavity; a sealing layer for sealing the light emitting element and filling the cavity; and a diffusion member having a plurality of light-shielding patterns formed at positions corresponding to the plurality of light-emitting elements one-to-one and laminated on an upper surface of the sealing layer such that vertical center axes of the corresponding light-emitting elements and the light-shielding patterns coincide with each other, wherein light emitted from the light-emitting elements is reflected and diffused by the light-shielding patterns, and is mixed in a region of the diffusion member and emitted.

Description

Area light source module for backlight device

Technical Field

The present invention relates to a display device, and more particularly, to an LED module for a backlight of a display device, which can simplify a structure and a manufacturing process by applying a highly transparent base material.

Background

In general, a Display Device includes a Television (TV) or a monitor as a Device for receiving and displaying a video signal, and various devices such as a Liquid crystal Display Device (LCD), an Organic Light Emitting Device (OLED), and a Plasma Display Device (PDP) are used as a means for displaying a video.

Unlike other display devices, a liquid crystal display device (LCD) cannot emit light by itself, and thus an additional external light source must be provided if it is desired to display a high-quality image. Therefore, the liquid crystal display device includes a backlight device of a surface light source in addition to the liquid crystal panel, so that the backlight device uniformly supplies a high-luminance light source to the liquid crystal panel, thereby embodying a high-quality image. As described above, the backlight device is a surface Lighting device for realizing an image of a display device such as a liquid crystal display device, and is classified into a Direct Lighting type (Direct Lighting type) or an Edge Lighting type (Edge Lighting type) backlight device according to a position where a light source is arranged. As a Light source of the backlight device, a Light Emitting Diode (hereinafter, referred to as "LED") having advantages such as small size, low power consumption, and high reliability is mainly used.

The LED element widely used in the direct illumination type backlight device can disperse light generated at the LED element for the first time in a large area by the secondary lens, so that not only the thickness of the backlight device can be reduced but also the light can be uniformly irradiated.

However, the conventional backlight device has a problem that the total thickness of the product is increased by inserting a specific mechanism such as a secondary lens, and there is a limit in realizing an ultra-thin and lightweight product or manufacturing a flexible product, and moldability is lowered. In order to solve such a problem, Korean laid-open patent No. 10-2015-0050655 describes a "surface light source display device".

As shown in fig. 1, the conventional surface light source display device based on the above-mentioned conventional document includes a substrate 11, a plurality of light emitting elements 12 formed thereon with a predetermined interval, and a first reflective layer 13 and a second reflective layer 14 formed on the lower surface and the upper surface of each of the light emitting elements 12. The space between the light emitting elements 12 is filled with a transparent resin layer 15, and a wavelength conversion sheet 16 is bonded to the light emitting elements 12 and the upper portion of the transparent resin layer 15.

In the surface light source display device, light emitted from the light emitting element 12 is reflected by the first reflective layer 13 and the second reflective layer 14, is emitted to the transparent resin layer 15 on the side surface, and is then emitted upward.

The conventional surface light source display device as described above exhibits advantages advantageous for ultra-thinning and weight reduction. However, in the conventional surface light source display device, since light of the light emitting element is guided to the side surface by the first reflective layer and the second reflective layer and is emitted, there is a disadvantage that the total luminance is not favorable.

Further, in the conventional surface light source display device, since the reflective layer is formed on the upper surface of the light emitting element, light cannot be sufficiently mixed (misting) in a dark region by the reflective layer and a light region therebetween, and there is a problem that uniformity of light is degraded.

In addition, in the conventional surface light source display device, when the light emitting element of the top view system is used to improve the luminance, a hot spot (hot spot) by the light emitting element may be observed, and the light characteristics may be degraded.

(Prior art document)

(patent document)

Korean laid-open patent No. 10-2015-0050655 (2015, 05, 11, published by application)

Disclosure of Invention

Problems to be solved

The invention aims to provide a surface light source module beneficial to ultra-thinning of a backlight device.

Another object of the present invention is to provide a surface light source module of a direct-illumination type backlight device that can exhibit high luminance and improve light uniformity by preventing hot spots.

Means for solving the problems

The surface light source module of the present embodiment for achieving the object as described above includes: a substrate printed with a circuit; a casting part which provides a plurality of cavities and is combined on the substrate; a light emitting element mounted on the substrate inside the cavity; a sealing layer for sealing the light emitting element and filling the cavity; and a diffusion member having a plurality of light-shielding patterns formed at positions corresponding to the plurality of light-emitting elements one-to-one and laminated on an upper surface of the sealing layer such that vertical center axes of the corresponding light-emitting elements and the light-shielding patterns coincide with each other, wherein light emitted from the light-emitting elements is reflected and diffused by the light-shielding patterns, and is mixed in a region of the diffusion member and emitted.

The sealing layer may be made of a silicon material having an adhesive force.

The light-shielding pattern may be formed on an upper surface of the diffusion member and may have a hemispherical, semi-elliptical, or polygonal pyramid-shaped three-dimensional structure.

The casting portion may have a first reflecting surface on a side surface of the cavity and a second reflecting surface on an upper surface of the cavity.

The first reflecting surface may be formed in an inclined surface or a convex curved surface.

ADVANTAGEOUS EFFECTS OF INVENTION

The invention has the following effects: the light uniformity is controlled by the diffusion component of the transparent resin raw material and the light shielding component formed on one surface of the diffusion component, so that an additional structure such as a light diffusion lens is not needed, and the ultra-thinning of the backlight device is facilitated, and the structure is simplified.

In addition, the present invention can fill the transparent resin in the cavity through the screen printing process, and can laminate the diffusion member without an additional bonding process, thereby simplifying the manufacturing process and saving the manufacturing time.

Drawings

Fig. 1 is a sectional view showing a related art surface light source display device,

fig. 2 is an exploded perspective view showing a main structure of a surface light source module of an embodiment of the present invention,

Fig. 3 is an I-I sectional view illustrating the surface light source module of fig. 2,

fig. 4 is a process diagram showing a process of manufacturing the surface light source module of the present embodiment,

fig. 5 is a sectional view showing a surface light source module according to another embodiment of the present invention.

Description of reference numerals

100: a substrate; 200: an LED element; 300: a casting section; 310: a cavity;

320: a first reflective surface; 330: a second reflective surface; 400: a sealing layer;

500: a diffusion member; 510: shading pattern

Detailed Description

The present invention and the technical problems to be solved by the present invention will be made apparent from the following description of preferred embodiments. Preferred embodiments of the present invention will be observed in detail with reference to the accompanying drawings, which follow.

The differences in the present embodiment described later are to be understood as matters not mutually exclusive. That is, it is to be understood that the features, structures, and characteristics described may be embodied in one embodiment as another embodiment without departing from the technical spirit and scope of the present invention, the positions or arrangements of individual constituent elements in each disclosed embodiment may be changed, similar reference numerals in the drawings refer to the same or similar functions in many respects, and the length, area, thickness, and the like and the forms thereof may be exaggerated for convenience of explanation.

Fig. 2 is an exploded perspective view showing a main structure of a surface light source module according to an embodiment of the present invention, and fig. 3 is an I-I sectional view showing the surface light source module of fig. 2.

As shown in these drawings, the surface light source module of the present embodiment includes: a substrate 100 printed with a circuit; a plurality of LED elements 200 mounted on the substrate 100; a molding portion 300 formed at a predetermined height to form a cavity (cavity)310 for disposing the LED element 200 on the substrate 100; a sealing layer 400 which fills the cavity 310 and seals the LED element 200; and a diffusion member 500 having a light-shielding pattern 510 and laminated on the sealing layer 400.

Specifically, as will be seen below, the substrate 100 may be printed with a prescribed circuit for driving the LED element 200, and the substrate 100 may include a Printed Circuit Board (PCB), a Flexible Printed Circuit Board (FPCB), or the like.

The LED element 200 is mounted on the substrate 100 as a light emitting source of the surface light source module by die bonding or wire bonding, and is electrically connected thereto. The LED elements 200 are mounted in a plurality in the horizontal, vertical, and arbitrary directions at predetermined intervals. The LED element 200 may be a top view (top view) type element emitting light toward the upper side or a multi-surface light emitting element including an upper light emitting surface.

The molding part 300 forms a cavity 310, and the cavity 310 is a space for mounting the LED element 200. Preferably, the casting part 300 for this is formed in a partition shape having a predetermined height on the substrate 100, and the height of the casting part 300 is at least higher than the height of the LED element 200, so that the LED element 200 can be protected. One or more LED elements 200 may be installed in one cavity 310 formed by the molding part 300. Such a casting portion 300 may be formed by bonding a resin of an insulating material to the substrate 100 after forming the resin into a plate shape, or may be formed by directly casting an insulating resin on the substrate 100 through a process such as insert molding.

The casting portion 300 functions as a reflecting member for reflecting light emitted from the LED element 200 while exposing the LED element 200 through the cavity 310. The casting part 300 for this may be composed of a raw material having a high reflectance. Thus, the casting part 300 includes: a first reflecting surface 320 formed at a side of the cavity 310 in a vertical direction; and a second reflecting surface 330 formed on an upper surface of the cavity 310. The first reflecting surface 320 forms a vertical reflecting surface to reflect light emitted from the LED element 200 to a side surface toward the light mixing space S, and the second reflecting surface 330 forms a horizontal reflecting surface to reflect light reflected from the light blocking pattern 510 or distributed to the light mixing space S to an upper side.

The sealing layer 400 functions to protect the LED element 200 by filling the inside of the cavity 310 with a transparent resin and to diffuse light emitted from the LED element 200. The sealing layer 400 used for this purpose may be made of a resin material having high transparency, and may be made of a transparent material including one or more of PS, PC, PMMA, PE, PET, PP, and MMA-styrene, for example, and the kind thereof is not limited as long as it has high transparency.

The sealing layer 400 may be formed by filling a transparent resin in a gel state into the cavity 310 through a Screen Printing process and curing the resin. Therefore, uniformity (uniformity) of the thickness, density, or the like of the sealing layer 400 can be improved. The sealing layer 400 may disperse the light scattering material in order to achieve light diffusion, as necessary. Further, a phosphor for converting the wavelength of light according to the type of the LED element 200 may be dispersed in the sealing layer 400.

The sealing layer 400 may be formed on the second reflecting surface 330 in order to effectively laminate the diffusion member 500 together with the space inside the cavity 310. In this case, the thickness of the sealing layer 400 formed on the second reflective surface 330 may be such that the diffusion member 500 can be bonded thereto, and a transparent resin may be printed on the surface of the second reflective surface 330 by screen printing. Therefore, the silicone resin constituting the sealing layer 400 has adhesiveness by itself, and thus the diffusion member 500 can be easily adhered even without using an additional adhering mechanism.

The diffusion member 500 is bonded to the upper surface of the sealing layer 400 to protect the sealing layer 400, and provides a light mixing space S for mixing light emitted from the LED element 200. The diffusion member 500 used for this purpose may be made of a highly transparent resin, and for example, a transparent sheet or plate such as PC, PS, PMMA, or the like may be used.

The diffusion member 500 has a thickness that ensures a minimum optical path OD in order to sufficiently mix light. Therefore, the surface light source device of the present embodiment can apply the diffusion member 500 having a predetermined thickness according to the emission characteristics of the LED element 200, and thus can provide a surface light source device exhibiting optimal light uniformity. In the present embodiment, the thickness of the diffusion member 500 may be 0.05mm to 4.5 mm.

The diffusion member 500 has a light-shielding pattern 510. The light blocking patterns 510 reflect and diffuse light emitted toward the upper surface of the LED device 200 toward the space between the LED devices, thereby improving the overall light uniformity of light emitted from the surface light source module. The light-shielding pattern 510 used for this purpose may be formed by applying ink or resin having a predetermined reflectance to the upper surface of the diffusion member 500.

The diameter of the light-shielding pattern 510 is at least larger than the diameter of the light-emitting surface of the LED element 200, and may have a three-dimensional structure in a hemispherical shape, a semi-elliptical shape, or a polygonal pyramid shape, for example. A plurality of light-shielding patterns 510 are formed at positions corresponding to the LED elements 200 at a one-to-one ratio. The diffusion member 500 having the light-shielding pattern 510 is directly bonded to the upper surface of the sealing layer 400 in a laminated manner. This is because, as the sealing layer 400 is formed of a resin material such as silicon, the diffusion member 500 can be easily bonded without an additional bonding member.

The surface light source module of the present embodiment controls the uniformity of light by the diffusion member as a transparent material and the light blocking member formed on one surface thereof, and thus does not require an additional structure such as a light diffusion lens, thereby facilitating ultra-thinning of the backlight device, being effective in simplifying the structure, and being manufactured by a process of directly laminating the diffusion member without an additional bonding member, thereby simplifying the manufacturing process.

Fig. 4 is a process diagram showing a manufacturing process of the surface light source module according to the present embodiment.

Referring to fig. 4, the surface light source module of the present embodiment prepares a substrate 100, mounts an LED element 200 on the substrate 100, and forms a casting 300 along the periphery of the LED element 200. The casting part 300 may be formed by fabricating a plate formed with the cavity 310 to be combined with the substrate 100 or by directly casting an insulating resin on the substrate 100. After preparing the substrate 100, as shown in the figure, the inside of the cavity 310 is filled with a transparent resin by screen printing. The filling of the transparent resin can be sufficiently performed only by about 1 to 2 screen printing, so that the process time can be shortened, and the filled transparent resin can have excellent uniformity. The filled transparent resin is cured under conditions to form a sealing layer.

Then, the diffusion member 500 having the light-shielding pattern 510 formed on one surface thereof is manufactured and disposed in an additional process, and the diffusion member 500 is laminated on the upper surface of the sealing layer 400 by using a rolling device. At this time, the plurality of light shielding patterns 510 and the LED elements 200 correspond in a one-to-one ratio, and are laminated in such a manner that the vertical central axes of the corresponding light shielding patterns 510 and the LED elements 200 coincide. The diffusion member 500 is bonded by the adhesive force of the sealing layer 400, and thus, an additional casting process for bonding may be omitted.

After the diffusion member 500 is laminated, the protective paper 500' for protecting the light-shielding pattern 510 is removed, thereby completing the surface light source module.

In the surface light source module of the present embodiment, the first reflecting surface 320 provided to the casting part 300 has an inclined surface structure. That is, the cavity 310 inclines the first reflection surface 320 upward such that the width increases toward the upper side. The first reflective surface 320 of such an inclined structure may disperse light emitted from the LED element 200 toward a space between the LED elements, so that light uniformity may be more improved.

Although not shown, the first reflecting surface 320 may have a convex curved surface shape. The curved first reflective surface 320 does not form a curved edge at the connection portion of the first reflective surface 320 and the second reflective surface 330, thereby relieving surface tension that may occur at the surface of the connection portion of the first reflective surface 320 and the second reflective surface 330. Accordingly, when the transparent resin for forming the sealing layer 400 is cured, the first reflective surface 320 of the convexly curved shape minimizes the occurrence of reflow (reflow) based on surface tension, so that it is possible to prevent the degradation of optical characteristics caused by the reflow.

As described above, although the illustrative embodiments of the present invention have been shown and described, many modifications and other embodiments may be made by one of ordinary skill in the art to which the present invention pertains. Such variations and other embodiments are contemplated and encompassed by the claimed invention, as deemed within the true spirit and scope of the invention.

Claims

1. A surface light source module for a backlight device is characterized in that,

the method comprises the following steps:

a substrate printed with a circuit;

a casting part which provides a plurality of cavities and is combined on the substrate;

a light emitting element mounted on the substrate inside the cavity;

a sealing layer for sealing the light emitting element and filling the cavity; and

a diffusion member having a plurality of light-shielding patterns formed at positions corresponding to the plurality of light-emitting elements one-to-one and laminated on an upper surface of the sealing layer such that vertical center axes of the corresponding light-emitting elements and the light-shielding patterns coincide with each other,

the light emitted from the light emitting element is reflected and diffused by the light shielding pattern, and is mixed in the region of the diffusion member and emitted.

2. The surface light source module for a backlight according to claim 1, wherein the sealing layer is made of a silicon material having an adhesive force.

3. The surface light source module for a backlight unit according to claim 1, wherein the light shielding pattern is formed on an upper surface of the diffusion member and has a three-dimensional structure in a shape of a hemispherical, semi-elliptical or polygonal pyramid.

4. The surface light source module of claim 1, wherein the casting portion has a first reflecting surface on a side surface of the cavity and a second reflecting surface on an upper surface of the cavity.

5. The surface light source module of claim 4, wherein the first reflecting surface is formed in an inclined surface or a convex curved surface.