KR101355815B1 - Light emitting device and lighting device having the same - Google Patents

Abstract

The present invention relates to a light emitting device and a lighting device including the same. The light emitting device according to the embodiment of the present invention includes an optical source and an optical lens. The optical lens includes a light incident surface to input the light from the optical source to the optical lens and a light output surface to which the light inputted to the light incident surface is emitted from the optical lens. The light incident surface includes a flat side and a convex curved side which are axially symmetrical based on a reference light axis. The light output surface includes two convex curved sides which are axially symmetrical based on the reference light axis.

Description

TECHNICAL FIELD [0001] The present invention relates to a light emitting device,

The present invention relates to a light emitting device and a lighting device having the same.

Recently, demand for flat panel display devices, which have been improved in size and weight and have improved performance, has been explosively increasing, centering on semiconductor technology which is rapidly developing.

Among these flat panel display devices, a liquid crystal display (LCD), which has been popular in recent years, has advantages such as miniaturization, light weight, and low power consumption, and is an alternative means to overcome the shortcomings of conventional cathode ray tubes And has been used in almost all information processing apparatuses requiring a display device at present.

A liquid crystal display device generally has a liquid crystal material injected between an upper substrate on which a common electrode and a color filter are formed, a lower substrate on which a thin film transistor and an electrode are formed, An electric field is formed by applying electric potential to deform the arrangement of liquid crystal molecules, thereby controlling the transmittance of light to thereby display an image. Since the liquid crystal display panel in the liquid crystal display device is a non-light emitting element that can not emit light by itself, it has a light emitting device such as a backlight unit for providing light to the liquid crystal display panel under the liquid crystal display panel.

The backlight unit includes a lamp, a light guide plate, a reflective sheet, an optical sheet, and the like. The lamp uses a cold-cathode tube type lamp having a relatively low calorific value and generating white light close to natural light, a long-life cold cathode tube type lamp, or an LED type lamp using a light-emitting diode (LED) with good color reproducibility and low power consumption. Conventionally, cold-cathode tube type lamps have been used, but LED type lamps have been used because of their excellent color reproducibility and low power consumption.

However, such a LED-type lamp has a problem in that light can not be uniformly dispersed throughout the liquid crystal display panel due to strong directivity of light.

SUMMARY OF THE INVENTION The present invention is directed to a light emitting device that emits light emitted from the same light source at a wide angle and does not generate bright spots and dark areas, and a lighting device having the same.

A light emitting device according to an embodiment of the present invention includes a light source and an optical lens, wherein the optical lens is a light incident surface in which light emitted from the light source is incident on the optical lens and the light incident on the light incident surface is the optical A light exit plane exiting the lens, the light entrance plane including a flat surface and a convex surface axially symmetrical with respect to the reference optical axis, the light exit surface being two convex curved surfaces axially symmetrical with respect to the reference optical axis It includes.

Here, the intersection of the light emitted from the light source and the reference optical axis as a reference point, θ1, an arbitrary angle formed by a straight line connecting an arbitrary point on the light incident surface and the reference point and the reference optical axis When the distance between the arbitrary point on the incident surface and the straight line connecting the reference point is R1, the specific angle formed between the specific point on the light incident surface and the straight line connecting the reference point and the reference optical axis is a1, 0≤θ1≤a1 In the range, R1 increases with the increase of θ1, and R1 decreases with the increase of θ1 in the range of a1 <θ1≤π / 2, and the straight line connecting the arbitrary point and the reference point on the light exit surface and the reference The angle formed by the optical axis is θ2, the distance between the arbitrary point on the light exit surface and the straight line connecting the reference point is R2, the straight line connecting the specific point on the light exit surface and the reference point and the reference optical axis When the constant angle a2, is within the range of 0≤θ2≤a2 R2 is reduced with the increase of θ2 and, a2 <θ2≤π in the range of / 2 is characterized in that R2 is increased with the increase of θ2.

An illumination apparatus according to an embodiment of the present invention includes a light emitting device having a light source and an optical lens, wherein the optical lens is incident on the light incident surface and the light incident surface in which light emitted from the light source is incident on the optical lens A light having a light exit surface exiting the optical lens, the light entrance plane comprising a flat surface and a convex curved surface axially symmetric with respect to a reference optical axis, the light exit surface being axial symmetric with respect to the reference optical axis It includes two convex surfaces.

The light emitting device and the lighting device including the light emitting device according to the embodiment of the present invention have the following effects.

First, the present invention spreads light emitted from a light source such as a light emitting diode at a wide angle, thereby preventing a bright spot and a dark portion from occurring.

Second, the present invention can effectively dissipate heat generated when a light source emits light.

1 is a cross-sectional view illustrating a light emitting device according to a first embodiment of the present invention.
2 is a view for explaining curvature design of an optical lens according to an embodiment of the present invention.
3 is a cross-sectional view illustrating a light emitting device according to a second embodiment of the present invention.
4 is a cross-sectional view illustrating a light emitting device according to a third embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, it is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It is intended that the disclosure of the present invention be limited only by the terms of the appended claims.

Also, terms used herein are for the purpose of illustrating embodiments and are not intended to limit the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. &Quot; comprises "and / or" comprising "used in the specification do not exclude the presence or addition of components other than the components mentioned. Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The angular representation in the parts not specifically mentioned in the present invention uses radians.

1 is a cross-sectional view illustrating a light emitting device according to a first embodiment of the present invention.

1, a light emitting device according to an embodiment of the present invention includes a light source 10 that emits light L and an optical lens 20 that is disposed so as to cover the outside of the light source 10.

In the present invention, the reference optical axis Z defines the reference optical axis Z as the vertical upward direction of the light source 10 in the sectional view of Fig. 1 in the traveling direction of the light at the center of the three-dimensional light emitted from the light source 10.

The reference point O in the present invention is a point at which a portion where light is emitted from the light source 10 and the reference optical axis Z intersects with the reference axis O when the bottom surface 20c of the optical lens 20 is an X- (Z) perpendicular to each other.

The light emitting device may have a rotationally symmetrical shape centering on the reference optical axis Z, but the light emitting device may have various shapes, and the present invention is not limited thereto.

The light source 10 is disposed inside the optical lens 20, and the direction of the light emitted from the light source 10 is changed by the optical lens 20. That is, the light emitted from the light source 10 is refracted by the optical lens 20 in the direction nearly perpendicular to the reference optical axis Z and diffused. For example, in the present invention, the light source 10 is a light emitting diode, and various types of light sources 10 are applicable.

The optical lens 20 diffuses the light emitted from the light source 10, and a transparent material having various refractive indices is possible. The optical lens may have a refractive index of between 1.45 and 1.60. For example, the transparent material of the optical lens 20 may be polymethyl methacrylate (PMMA), polycarbonate (PC), or the like.

The optical lens 20 has a space in which the light source 10 can be disposed and has a light incident surface 20a as an inner surface, a light outgoing surface 20b as an outer surface, a light incident surface 20a, And a bottom surface 20c connecting the exit surface 20b.

The light incident surface 20a is a portion where the light emitted from the light source 10 is incident on the optical lens 20. [ The light incident surface 20a has a shape that is axially symmetrical with respect to the reference optical axis Z. In particular, the portion near the reference optical axis Z is a flat surface, and the light incident surface 20a is a bottom surface 20c are connected to each other by a convex curved surface. That is, the light incident surface 20a intersects with the reference optical axis Z perpendicularly.

The light incident surface 20a has an angle formed by a straight line connecting an arbitrary point on the light incident surface 20a and the reference point O with the reference optical axis Z as? 1, an arbitrary point on the light incident surface 20a And the reference point O is R1 and the specific angle formed by the reference optical axis Z and the straight line connecting the reference point O with the point A which is a specific point on the light incident surface 20a is a1, In the range of 0?? 1? A1, R1 increases with increase of? 1, and in the range of a1 <? 1?? / 2 where the light incident surface 20a is connected to the bottom surface 20c at the point A, R1 is decreased according to. Here, the inclination in the range of a1 <? 1?? / 2, which is the portion where the light incident surface 20a is connected to the bottom surface 20c at the point A, becomes larger.

In this case, a1 means the maximum angle of? 1 in the range where R1 increases, and a1 can be angles of various sizes. For example, a1 may have an angle in the range of 0 <a1 <? / 15.

The point of intersection of the reference point O and the light incidence plane 20a and the intersection of the reference optical axis Z and the light incidence plane 20a are defined as three vertexes and R1 and the light incidence plane 20a ), The sides of the reference optical axis Z from the reference optical axis Z to the point A are connected to form a right triangle.

The light exit surface 20b is a portion where the light incident on the light incident surface 20a is emitted from the optical lens 20. The light exit surface 20b includes two convex surfaces that are axially symmetrical with respect to the reference optical axis Z. [ For example, the light exit surface 20b is formed into a convex curved surface with a small convex surface with reference to the reference optical axis Z, and a convex curved surface from a specific point B to a portion connected to the bottom surface 20c.

The light exit surface 20b has an angle formed by a straight line connecting an arbitrary point on the light exit surface 20b and the reference point O with the reference optical axis Z as? 2, an arbitrary point on the light exit surface 20b When the distance between the straight line connecting the reference point O and the straight line connecting the reference point O and the point B which is a specific point on the light exit surface 20b and the reference optical axis Z is a2, In a range of 0?? 2? A2, which is a specific B point that is the curvature of the light exit surface 20b, R2 decreases with an increase of? 2, and the bottom 20c at a specific B point, which is the curvature of the light exit surface 20b, R2 is increased in accordance with the increase of? 2 in the range of a2 <? 2?

In this case, a2 means a maximum angle of? 2 in a range where R2 decreases, and a2 can be angles of various sizes. For example, a2 may have an angle in the range of 0 < a2 <

2 is a view for explaining curvature design of an optical lens according to an embodiment of the present invention.

Referring to FIG. 2, the curvature of the optical lens 20 according to the embodiment of the present invention can be designed by dividing the light exit surface 20b by a sag.

The equation for designing the curvature of the light exit surface 20b of the optical lens 20 of the present invention is expressed by Equation 1 below. At this time, the curvature of the light exit surface 20b is a curvature in the range of a2 <? 2?? / 2 where the light exit surface 20b from the point B to the point where the light exit surface 20b is connected to the bottom surface 20c .

For example, the curvature of the light exit surface 20b of the optical lens 20 has a maximum value at a light distribution of 78 to 80 degrees after the light divided by n degrees is refracted by the light incident surface 20a, It is possible to design the light output surface 20b by dividing the light output surface 20b into segments so as to obtain a specific illuminance distribution.

The equation for designing the curvature of the light incident surface 20a of the optical lens 20 of the present invention is expressed by Equation 2 below. At this time, the curvature of the light incidence surface 20a is a curvature in a range of a1 <? 1?? / 2 where the light incidence surface 20a from the point A to the point where it is connected to the bottom surface 20c .

은 광학렌즈(20)의 굴절률,

는 공기의 굴절률,

는 x축과 광출사면(20b) 또는 광입사면(20a) 새그먼트가 이루는 각도,

은 광출사면(20b) 또는 광입사면(20a) 새그먼트의 법선과 광선이 이루는 입사각,

은 스넬의 법칙에 의해 굴절되어 나가는 광의 출사각,

는 광출사면(20b) 또는 광입사면(20a) 새그먼트에 대해 의 각도로 출사되는 빛이 리시버(Receiver, 40)에 도달할 때 리시버(40)의 법선과 이루는 각도를 의미한다.here,

The refractive index of the optical lens 20,

The refractive index of air,

Angle formed by the x-axis and the light emitting surface 20b or the light incident surface 20a,

The incident angle formed by the normal line of the light emitting surface 20b or the light incident surface 20a and the light ray,

The outgoing angle of the light refracted by Snell's law,

Refers to an angle formed by the normal to the receiver 40 when light emitted at an angle to the light emitting surface 20b or the light incident surface 20a reaches the receiver 40. [

In the present invention, the optical lens 20 has a curvature in a range of the light exit surface 20b a2 <? 2?? / 2 that is larger than a curvature in the range of the light incident surface 20a a1 <? 1? The light emitted from the light source 10 is incident on the light incident surface 20a and refracted so that the refracted light passes through the light exit surface 20b in contact with the outside and can be designed to have a wide directivity angle.

As described above, according to the present invention, the outgoing angle of light can be adjusted by adjusting the curvatures of the light incident surface 20a and the light outgoing surface 20b, thereby adjusting the light source 10's characteristics and the light- Can be controlled. By doing so, the light emitting device according to the embodiments of the present invention has the effect of reducing the number of bright spots and dark areas.

3 is a cross-sectional view illustrating a light emitting device according to a second embodiment of the present invention.

The light emitting device of FIG. 3 is different from the light emitting device of the first embodiment of FIG. 1 in that the bottom surface 20c is divided into two parts and includes the fixing part 30, Description of the same parts as in the first embodiment will be omitted.

Referring to FIG. 3, the bottom 20c can be divided into an inside and an outside. When the light source 10 side is directed to the inside and the other side is directed to the outside from the point C, And the outer surface of the protrusion is further protruded downward. This is advantageous in that the light emitted from the light source 10 can be efficiently emitted.

At this time, the inside of the bottom surface 20c can be corroded or patterned in a 3D shape.

The optical lens 20 may also include a fixing portion 30 that is coupled to the illumination device within the bottom surface 20c, e.g., the bottom surface 20c, wherein the fixing portion 30 has at least two can do

4 is a cross-sectional view illustrating a light emitting device according to a third embodiment of the present invention.

The light emitting device of Fig. 4 differs from the light emitting device of the second embodiment of Fig. 3 in the shape of the light emitting surface 200b.

Referring to FIG. 4, the light exit surface 200b includes a plane axially symmetric with the reference optical axis Z and parallel to the reference optical axis Z. That is, the light exit surface 200b of a specific length is parallel to the reference optical axis Z at the portion where the light exit surface 200b is connected to the bottom surface 200c.

The light exit surface 200b is an angle formed by a straight line connecting an arbitrary point on the light exit surface 200b and the reference point O and the reference optical axis Z, θ2, and an arbitrary point and reference point on the light exit surface 200b. The distance between the straight line connecting (O) is R2, and the first angle formed by the reference line (Z) and the straight line connecting the specific point B (first point) on the light exit surface 200b and the reference point O is a2, When the second angle formed by the straight line connecting the specific point D (second point) on the light exit surface 200b and the reference point O and the reference optical axis Z is a3, in the range of 0≤θ2≤a2, R2 decreases with increase, R2 increases with increase of θ2 in the range of a2 <θ2≤a3, and R2 decreases with increase of θ2 in the range of a3 <θ2≤π / 2.

In the present invention, the curvature design of the optical lens in the light emitting devices according to the second and third embodiments may be designed like the optical lens in the light emitting device of the first embodiment described with reference to FIG.

In the present invention, the radius or height of the body, such as the distance from the reference optical axis to the light incident surface, the distance from the reference optical axis to the light exit surface, etc., is changed and the curvature of the light incident surface and the light exit surface is designed, The present invention is also applicable to a light emitting device including a light emitting device.

Therefore, by using the optical lens of the present invention, it is possible to direct the light emitted from the light source toward the forward direction, and to transmit light to a desired region.

The light emitting device described above includes one optical lens in one light source, and a plurality of light emitting devices can form one lighting device. It is noted that the present invention is also applied to a lighting apparatus provided with the light emitting device of the various embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be appreciated that one embodiment is possible. Accordingly, the true scope of the present invention should be determined by the technical idea of the claims.

10, 100: light source
20, 200: Optical lens
20a, 200a: light incidence plane
20b, 200b: light emitting surface
20c, 200c: bottom surface
30, 300:
O: Reference point
Z: reference optical axis

Claims (8)

A light emitting device comprising a light source and an optical lens,
Wherein the optical lens has a light incident surface on which light emitted from the light source is incident on the optical lens and a light exit surface on which light incident on the light incident surface is emitted from the optical lens,
The light incidence surface includes a flat surface and a convex surface that are axisymmetric with respect to a reference optical axis,
The light exit surface includes two convex curved surfaces axially symmetric with respect to the reference optical axis,
Wherein a reference point is defined as an intersection point between a portion where light is emitted from the light source and the reference optical axis,
A distance between a straight line connecting an arbitrary point on the light incidence surface and the reference point and an arbitrary angle formed by the reference optical axis is? 1, a straight line connecting an arbitrary point on the light incidence surface and the reference point is R1, When a specific angle formed by a straight line connecting a specific point on the plane and the reference point and the reference optical axis is a1, R1 increases with increase of? 1 in the range of 0?? 1? A1, In the range, R1 decreases with increase of? 1,
Θ2 is the angle formed by a straight line connecting the arbitrary point on the light exit surface and the reference point and the reference optical axis is θ2, and the distance between the arbitrary point on the light exit plane and the straight line connecting the reference point is R2, on the light exit surface When a specific angle formed by a straight line connecting a specific point and the reference point and the reference optical axis is a2, in the range of 0≤θ2≤a2, R2 decreases with increasing θ2, and in the range of a2 <θ2≤π / 2 Light emitting device characterized in that R2 increases with the increase of θ2. delete The method of claim 1,
Wherein a1 is an angle within a range of 0 <a1 <π / 15 and a2 is an angle within a range of 0 <a2 <2π / 45. The method of claim 3,
The optical lens further comprises a bottom surface connecting the light incident surface and the light exit surface, wherein the bottom surface is a light emitting device characterized in that the outside protrudes further down than the inside. 5. The method of claim 4,
The optical lens further comprises at least two fixing parts on the bottom surface. A light emitting device comprising a light source and an optical lens,
Wherein the optical lens has a light incident surface on which light emitted from the light source is incident on the optical lens and a light exit surface on which light incident on the light incident surface is emitted from the optical lens,
The light incidence surface includes a flat surface and a convex surface that are axisymmetric with respect to a reference optical axis,
The light emitting surface includes two convex curved surfaces axially symmetrical with respect to the reference optical axis and a surface axially symmetrical with respect to the reference optical axis and parallel to the reference optical axis,
Wherein a reference point is defined as an intersection point between a portion where light is emitted from the light source and the reference optical axis,
A distance between a straight line connecting an arbitrary point on the light incidence surface and the reference point and an arbitrary angle formed by the reference optical axis is? 1, a straight line connecting an arbitrary point on the light incidence surface and the reference point is R1, When a specific angle formed by a straight line connecting a specific point on the plane and the reference point and the reference optical axis is a1, R1 increases with increase of? 1 in the range of 0?? 1? A1, In the range, R1 decreases with increase of? 1,
Θ2 is the angle formed by a straight line connecting the arbitrary point on the light exit surface and the reference point and the reference optical axis is θ2, and the distance between the arbitrary point on the light exit plane and the straight line connecting the reference point is R2, on the light exit surface When a specific angle formed by a straight line connecting a specific point and the reference point and the reference optical axis is a2, in the range of 0≤θ2≤a2, R2 decreases with the increase of θ2, and in the range of a2 <θ2≤π / 2 Light emitting device characterized in that R2 increases with the increase of θ2. delete An illuminating device comprising the light emitting device according to claim 1.

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