KR100947440B1 - Orientation angle changing lens and light emitting device comprising the same - Google Patents

Abstract

Disclosed is a directed angle conversion lens of light positioned above the light emitting diode. The disclosed angle conversion lens is radially symmetric about a central axis, the outer surface of the central axis becomes a convex curved surface, and an outgoing surface having a concave shape inside the curved surface, and radially around the central axis. It comprises a light incident surface which is symmetrical and has a concave shape.

Direct Angle, Light Emitting Diode, Light Emitting Surface, Light Receiving Surface, Curved Surface, Package, LED

Description

ORIENTATION ANGLE CHANGING LENS AND LIGHT EMITTING DEVICE COMPRISING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens for converting a directivity angle of light generated in a light emitting diode, and more particularly, to a directivity conversion lens configured to widen a directivity angle of light and a light emitting device for a backlight including the same.

A light emitting diode (LED) is a semiconductor light emitting device in which electrons and holes meet and emit light at a PN junction by applying an electric current. A light emitting diode (LED) is typically a package structure including an LED chip (or a die). The light emitting device having such a structure is often referred to as an 'LED package'.

Typically, the LED package includes an encapsulant for protecting the LED chip from the outside. In addition, the LED package may include a housing on which the leadframe is supported for power application, or may include a PCB on which a circuit pattern for power application is formed. In the case of the LED package including the housing, the encapsulant is filled in the cavity formed in the housing, and when the LED chip is mounted on the PCB, the encapsulant is formed by transfer molding or the like to cover the LED chip on the PCB. In addition, there is an LED package of a lamp type structure.

A light emitting device having an LED package or similar function is mainly used as a light source of a backlight unit. In particular, the direct type backlight unit is configured such that a plurality of LED packages are arranged at regular intervals under an illumination object such as an LCD panel. In this case, the plurality of LED packages adjacent to each other may be to emit light of different colors or wavelengths to implement white light.

In the backlight unit as described above, in order to obtain high uniformity of light and reduce color deviation, light mixing between neighboring LED packages should be uniform. And, for such uniform light mixing, it is preferable that the light amount or light intensity outside the center of the LED package is larger than the light amount or light intensity at the center. For example, in a direct backlight unit having a structure in which a plurality of LED packages are spaced at 35 mm pitch intervals, the peak angle of the directivity angle curve is 67 degrees, and the light amount or light intensity at the center portion is the light amount at the peak angle. Alternatively, the inventors have found that the uniformity of light becomes very good when it is about 40% of the light intensity.

Accordingly, a technical object of the present invention is to provide a direct-angle conversion lens that is provided on an upper surface of a light emitting diode such as an LED package and changes the directivity angle of light emitted from the light-emitting diode so that the peak angle of the directivity curve is located outside the center. To provide.

In addition, another technical object of the present invention is to use a divergence angle conversion lens for varying the divergence angle of the light emitted from the light emitting diode such that the peak angle of the divergence angle curve is located outside the center, thereby increasing the uniformity (more, It is to provide a light emitting device capable of providing a backlight light source (which greatly reduces the deviation).

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According to an aspect of the present invention, there is provided a direct-angle conversion lens of light, which is located on top of the light emitting diode and is solid. The direct-angle conversion lens has a pair of circle components intersecting at the center axis when viewed in a vertical section passing through the center axis of the lens, the circle components being symmetrical with respect to the center axis line, the circle A light emitting surface having a concave shape between the components, and left and right with respect to the central axis when viewed in a vertical section passing through the central axis of the lens to symmetrically collect light from the light emitting diodes into each of the original components. And a light incident surface having a symmetrical concave shape. In this case, the orientation angle conversion lens is preferably made of a light-transmissive resin such as silicon or epoxy, and a phosphor may be included therein.
Preferably, the light incident surface is a conical surface whose vertex is located on the central axis, and the conical light incident surface is suitable for sending light to the convex surface of the light exiting surface deviating outside the central axis. In this case, the light incident surface is spaced apart from the light emitting diode, and an air layer is present between the light incident surface and the light emitting diode. In addition, the light exit surface is preferably determined by the rotational trajectory of the original component.

According to another aspect of the present invention, there is provided a light emitting device for a backlight, which is provided on the light emitting diode and above the light emitting diode, and comprises a solid angle conversion lens, wherein the direction angle conversion lens is a central axis of the lens. When viewed from the vertical section passing through a pair of circle components intersecting at the central axis, the circle components are symmetrical with respect to the central axis, and the light emitting surface having a concave shape between the circle components And a light incident surface having a concave shape that is symmetrical with respect to the center axis when viewed in a vertical section passing through the center axis of the lens to symmetrically collect light from the light emitting diodes into each of the original components. .
Preferably, the light emitting diode is an LED package including an LED chip and an encapsulant encapsulating the LED chip, wherein the light incident surface is spaced apart from an encapsulant of the LED package, and the encapsulant and the mouth are separated. It is preferable that an air layer exists between the light surfaces. Furthermore, it is preferable that the LED chip coincides with or is located around the central axis.

According to an embodiment of the present invention, by varying the directivity angle pattern of the light emitted from the light emitting diode such that the peak angle of the directivity curve is located outside the center, it is possible to provide a backlight light source that is more uniform and further reduces color deviation. can do.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to ensure that the spirit of the present invention can be fully conveyed to those skilled in the art. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. And, in the drawings, the width, length, thickness, etc. of the components may be exaggerated for convenience. Like numbers refer to like elements throughout.

1 is a perspective view showing a backlight light emitting device according to an embodiment of the present invention, Figure 2 is a cross-sectional view of the backlight light emitting device shown in FIG. 1 and 2, only the characteristic components of the present invention are shown and used in the operation or other functions of the light emitting device such as leadframes, electrical circuits or electrical wirings, but are not directly related to the spirit of the present invention. Few components have been omitted for simplicity of the drawings.

As shown in Fig. 1 and Fig. 2, the light emitting device 1 of the present embodiment includes an LED package 2 and a direction conversion lens 3. The directivity conversion lens 3 is disposed on top of the LED package 2, and is bonded to the top surface of the LED package 2 by, for example, an adhesive or the like, or in some other way, the LED package 2. It can be coupled to the upper surface of.

As shown in FIG. 1, the directivity conversion lens 3 is a structure formed of a spherical or aspherical curved surface in which the vicinity of the center is concave and the convex is contiguous, which will be described in more detail below. According to a preferred embodiment, the light emitting device 1 includes an LED package 2 as a light emitting diode, but it may also be considered to use an unpackaged LED chip instead of the LED package 2.

Referring to FIG. 2, the LED package 2 may include a housing 21 having a cavity formed at an upper center thereof, and an encapsulant 23 made of a light transmissive material (eg, silicon or epoxy material) formed in the cavity. Include. The LED chip 22 is located at the bottom of the cavity and is covered by the encapsulant 23 and protected from the outside. Although not shown, the LED chip 22 may be mounted on, for example, a lead frame to receive light from the lead frame to emit light. In addition, although only one LED chip 22 is shown in the figure, it is also within the scope of the present invention to use a plurality of LED chips.

The direction conversion lens 3 is formed of a light transmissive material such as, for example, silicon or epoxy. In addition, the directivity conversion lens 3 has a structure that is radially symmetric with respect to the central axis y with the light incident surface 31 and the light exit surface 32 (see FIG. 1). At this time, the light incident surface 31 is a surface into which light from the LED package 2, that is, light exiting from the LED chip 22 through the encapsulant 23, enters the light exit surface 32. Light passing through the lens 3 exits to the outside.

In the embodiment of the present invention, the light incident surface 31 is spaced apart from the top surface of the encapsulant 23 of the LED package 22. Therefore, an air layer 4 exists between the light incident surface 31 and the encapsulant 23. Further, the light incident surface 31 is a surface symmetrically radially about the central needle axis y, and as shown in FIG. 2, a vertex is a conical surface located on the center axis line y. . In addition, the light exit surface 32 is radially symmetric about the center axis y, and the outer surface of the center axis y is a convex curved surface, and the inside of the curved surface is concave.

FIG. 3 is a view for explaining the directivity conversion lens 3 in more detail. Referring to FIG. 3, the conical light incident surface 31 may have a difference in refractive index with air of the resin constituting the lens 3. The light is refracted in the direction away from the central axis y by its inclined angle. And, the refracted light is mainly directed to the convex curved surface outside of the central axis y.

The light exit surface 32 is formed to be concave around the central axis y and convex on the outside thereof, thereby allowing more light to be emitted at the outer side, that is, the convex curved surface than near the central axis y. . This greatly reduces the amount of light or light intensity near the center of the lens and increases the amount of light or light intensity near the outside of the lens, thereby greatly contributing to widening the directing angle of the light. More preferably, the light exit surface 32 is a curved surface determined by a rotational trajectory of a curve including a pair of original components c1 and c2 intersecting at the central axis y. By designing the light exit surface 32 using a pair of original components c1 and c2, it is possible to easily obtain a lens with a lot of light emission from the outer side rather than the center.

FIG. 4 is a diagram illustrating a direction in which light is changed by the aforementioned angle conversion lens 3, and FIG. 5 is a graph of a direction angle curve of a light emitting device using the angle conversion lens 3.

4 and 5, it can be seen that when the direction conversion lens 3 is used, the light intensity is relatively decreased at the center of the glen, while the light intensity is greatly increased outside the lens. In particular, referring to FIG. 5, it can be seen that the peak angle of the directivity angle curve is 67 degrees, and the light intensity at the center portion is about 40% of the light intensity at the peak angle. At this time, when a directivity conversion lens for creating a directivity angle curve as shown in FIG. 5 is used for a backlight unit having a pitch interval of 35 mm between neighboring light emitting devices, light uniformity of 85% or more can be obtained.

1 is a perspective view of a light emitting device for a backlight according to an embodiment of the present invention.

2 is a cross-sectional view of the light emitting device for a backlight shown in FIG.

FIG. 3 is a view for explaining in detail a direction conversion lens that is a part of the light emitting device for backlight shown in FIGS. 1 and 2;

FIG. 4 is a view illustrating a direction in which the directivity conversion lens illustrated in FIG. 3 converts a directivity angle of light.

5 is a directed angle curve graph of a light emitting device for a backlight according to an embodiment of the present invention.

Claims (9)

Located in the upper portion of the light emitting diode, and a solid-angle conversion lens of the light, When viewed in a vertical section passing through the center axis of the lens, it has a pair of circle components intersecting at the center axis line, the circle components are symmetrical with respect to the center axis line, the concave shape between the circle components A light emitting surface having; A light incident surface having a concave shape that is symmetrical with respect to the center axis when viewed in a vertical section passing through the center axis of the lens to symmetrically collect light from the light emitting diodes into each of the original components, And the light incident surface is a conical surface in which a vertex is located on the center axis line. delete The directional conversion lens of claim 1, wherein the light incident surface is spaced apart from the light emitting diode, and an air layer is present between the light incident surface and the light emitting diode. The lens of claim 1, wherein the light exit surface is determined by a rotational trajectory of the original components. A light emitting device for a backlight comprising a light emitting diode and a solid-angle direct conversion lens provided on an upper portion of the light emitting diode, wherein the direct conversion angle conversion lens comprises: When viewed in a vertical section passing through the center axis of the lens, it has a pair of circle components intersecting at the center axis line, the circle components are symmetrical with respect to the center axis line, the concave shape between the circle components A light emitting surface having; A light incident surface having a concave shape that is symmetrical with respect to the center axis when viewed in a vertical section passing through the center axis of the lens to symmetrically collect light from the light emitting diodes into each of the original components, And the light incident surface is a conical surface having a vertex located on the center axis. The light emitting device of claim 5, wherein the light emitting diode is an LED package including an LED chip and an encapsulant for encapsulating the LED chip. The light emitting device of claim 5, wherein the light emitting surface is determined by a rotational trajectory of the original components. The light emitting device of claim 6, wherein the light incident surface is spaced apart from the encapsulant of the LED package, and an air layer is present between the encapsulant and the light incident surface. The light emitting device of claim 6, wherein the LED chip coincides with the center axis or is positioned around the center axis.

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