KR20200069156A - Lens for wide diffusion light - Google Patents

Abstract

According to an embodiment of the present invention, a light diffusing lens comprises: a lower surface; an incident surface concavely formed from the lower surface to the inside thereof; and an exit surface for emitting light incident through the incident surface and including planar long and short axes. The exit surface includes: an upper surface formed in a curved surface; and first and second side surfaces disposed to face each other between the upper and lower surfaces. The height (H1) in a short axial direction of each of the first and second side surfaces is smaller than the height (H2) of a long axial direction. Accordingly, an upper light diffusing lens is formed to have the planar long and short axes, the height of the long axis is designed to be higher than that of the long axis and thus, generation of leakage of light from the long axis can be prevented.

Description

Light diffusion lens {LENS FOR WIDE DIFFUSION LIGHT}

The embodiment relates to a light diffusing lens. More specifically, it relates to a light diffusion lens used in a backlight module of a liquid crystal display device to improve light uniformity.

The demand for flat panel display devices with improved performance has been explosively increased due to their small size and light weight, centering on rapidly developing semiconductor technologies.

Among these flat panel display devices, a liquid crystal display (LCD), which has recently been spotlighted, has advantages such as miniaturization, light weight, and low power consumption, so that it can overcome the disadvantages of the conventional cathode ray tube (CRT). As an alternative means, it has been gradually attracting attention, and it is currently installed and used in almost all information processing devices requiring display devices.

Since a liquid crystal display panel in a liquid crystal display device is a light-receiving element that cannot emit light by itself, a backlight unit is provided under the liquid crystal display panel to provide light to the liquid crystal display panel. Here, the backlight unit includes a lamp, a light guide plate, a reflective sheet, and optical sheets. In addition, the lamp has a relatively small amount of heat, generates white light close to natural light, and uses a long-life cold cathode ray tube type lamp or a light-emitting diode (hereinafter referred to as'LED') that has good color reproducibility and consumes low power. Anticorrosion lamps are used. In the past, a cold cathode ray tube type lamp was used, but since the LED type lamp has the advantage of good color reproducibility and low power consumption, LED type lamp products have begun to be used.

1 is a view showing the arrangement and light distribution of a plurality of lenses having isotropic surface irradiation characteristics.

Referring to FIG. 1, a plurality of conventional lenses 2 having isotropic surface irradiation characteristics may be disposed on the substrate 20 at equal intervals. At this time, the lens 2 may be disposed to cover a light source mounted on the substrate 20.

As illustrated in FIG. 1, there is a problem in that a mura in the form of a dark portion occurs in a diagonal direction with respect to one lens 2. For example, when an LED is used as the light source, the light emitted by the LED tends to concentrate in the front direction of the LED because of its strong straightness. Accordingly, there is an increasing demand for a technique for effectively and uniformly diffusing the light of a plurality of LEDs.

Therefore, the lens technology that can improve the uniformity of light by designing the incident surface where light enters and the emitting surface through which light is emitted to implement an anisotropic surface irradiation, and minimizing the dark portion generated in the diagonal direction of the lens based on this, The demand for the situation is also increasing.

An embodiment provides a light diffusion lens having an incident surface on which light is incident and an emitting surface on which light is emitted so as to minimize dark portions generated in a diagonal direction of the plurality of light diffusion lenses.

It is formed to have a long axis and a short axis on a flat surface, and provides a light diffusion lens that prevents leakage light from being generated on the long axis side by designing a height of the long axis side higher than the height of the short axis side.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned herein will be clearly understood by those skilled in the art from the following description.

The subject, according to the embodiment, the lower surface; An incident surface concavely formed from the lower surface to the inside; And an emission surface through which the light incident through the incident surface is emitted and includes a long axis and a short axis on a plane, and the emission surface is disposed to face each other between the upper surface formed by the curved surface and the upper surface and the lower surface. It includes one side surface and a second side surface, and the height H1 in the short axis direction of each of the first side surface and the second side surface is achieved by a light diffusion lens smaller than the height H2 in the long axis direction.

Here, the first side surface and the second side surface may further include an edge formed to meet, and the edges disposed to face each other in the long axis direction may be disposed parallel to the optical axis.

In addition, the absolute value of the tangential slope of the upper surface with respect to the curved surface may increase from the edge toward the optical axis.

Further, among the light irradiated on the upper surface, light irradiated toward the long axis at a predetermined angle (θ) with respect to the optical axis may be refracted to the corner by the upper surface.

Alternatively, the light irradiated toward the long axis at a predetermined angle (θ) with respect to the optical axis among the light irradiated to the upper surface is an area where the first and second exit surfaces meet by the upper surface. Can be refracted.

Here, the angle θ may be 52.5 degrees or less.

Further, the height of the short axis direction H1 of each of the first side surface and the second side surface may be 0.5 or more and less than 1 compared to the height H2 of the long axis direction.

Here, the upper end of the first side surface and the second side surface may be formed to have a predetermined curvature.

In addition, the height (H1) in the minor axis direction of the first side surface and the second side surface may be 2.8 to 3.0 times the height (H3) of the vertex (P2) which is one point of the upper surface disposed on the optical axis (C) line. have.

On the other hand, the length of the long axis may be more than 1.1 times the length of the short axis.

In addition, the lower surface may be formed in an oval shape.

The light diffusion lens according to the embodiment is formed to have a long axis and a short axis on a plane, and a height of the long axis is designed to be higher than the height of the short axis, thereby preventing leakage of light from the long axis. Accordingly, light uniformity is improved at the edge of the long axis side and asymmetric light distribution can be realized.

At this time, the upper surface may be formed as a curved surface to reflect light irradiated below 52.5 degrees based on the optical axis.

Various and beneficial advantages and effects of the embodiments are not limited to the above, and may be more easily understood in the process of describing specific embodiments of the embodiments.

1 is a view showing the arrangement and light distribution of a plurality of lenses having isotropic surface irradiation characteristics,
2 is a perspective view showing a light diffusing lens according to the first embodiment,
3 is a plan view showing a light diffusion lens according to the first embodiment,
4 is a bottom view showing a light diffusing lens according to the first embodiment,
5 is a front view showing a light diffusing lens according to the first embodiment,
6 is a side view showing a light diffusing lens according to the first embodiment,
7 is a cross-sectional view of a short axis direction based on an upper surface of the light diffusing lens according to the first embodiment,
8 is a cross-sectional view of a long axis direction based on an upper surface of the light diffusion lens according to the first embodiment,
9 is a view showing light distribution according to a long axis length compared to a short axis length of the light diffusion lens according to the first embodiment,
10 is a view showing experimental results of a conventional light diffusing lens and a light diffusing lens according to the first embodiment,
11 is a view showing light diffusion in a long axis direction and a short axis direction of the light diffusion lens according to the first embodiment,
12 is a view showing a light source irradiating light to the incident surface of the light diffusing lens according to the embodiment,
13 is a perspective view showing a light diffusing lens according to a second embodiment,
14 is a plan view showing a light diffusing lens according to a second embodiment,
15 is a bottom view showing a light diffusing lens according to the second embodiment,
16 is a front view showing a light diffusing lens according to the second embodiment,
17 is a side view showing a light diffusing lens according to a second embodiment,
18 is a cross-sectional view of a short axis direction based on an upper surface of a light diffusing lens according to a second embodiment,
19 is a cross-sectional view of a long axis direction based on an upper surface of a light diffusion lens according to a second embodiment.

The present invention can be applied to various changes and can have various embodiments, and specific embodiments will be illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as second and first may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, the second component may be referred to as a first component without departing from the scope of the present invention, and similarly, the first component may also be referred to as a second component. The term and/or includes any combination of a plurality of related described items or any of a plurality of related described items.

When an element is said to be "connected" to or "connected" to another component, it is understood that other components may be directly connected to or connected to the other component, but may exist in the middle. It should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that no other component exists in the middle.

In the description of the embodiment, when one component is described as being formed "on (up) or down (down)" (on or under) of the other component, the upper (up) or lower (down) (on or under) includes both two components directly contacting each other or one or more other components formed indirectly between the two components. In addition, when expressed as'on (up) or down (on or under)', it may include the meaning of the downward direction as well as the upward direction based on one component.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, but the same or corresponding components are assigned the same reference numbers regardless of reference numerals, and redundant descriptions thereof will be omitted.

The first Example

2 is a perspective view showing a light diffusing lens according to the first embodiment, FIG. 3 is a plan view showing the light diffusing lens according to the first embodiment, and FIG. 4 is a bottom view showing the light diffusing lens according to the first embodiment , Fig. 5 is a front view showing the light diffusing lens according to the first embodiment, Fig. 6 is a side view showing the light diffusing lens according to the first embodiment, and Fig. 7 is an upper part of the light diffusing lens according to the first embodiment 8 is a cross-sectional view of the minor axis direction with respect to the surface, and FIG. 8 is a cross-sectional view of the long axis direction with respect to the upper surface of the light diffusing lens according to the first embodiment. Here, FIG. 7 is a cross-sectional view showing the A-A line in FIG. 3, and FIG. 8 is a cross-sectional view showing the B-B line in FIG. 3. In Fig. 2, the x-direction is the minor axis direction of the exit surface, the y-direction is the major axis direction of the exit surface, and the z-direction indicates the optical axis direction.

Meanwhile, the optical axis C is the center of light irradiated from the light source, and may coincide with the center of the light diffusion lens 1.

The light diffusing lens 1 according to the first embodiment can be used in a liquid crystal display. In this case, the liquid crystal display device may include a substrate and a plurality of light sources mounted on the substrate. In addition, the light diffusion lens 1 may be arranged to cover the light source to implement asymmetric light distribution. Accordingly, the liquid crystal display in which the light diffusion lens 1 is disposed can form an asymmetrical light distribution through the light diffusion lens 1 to prevent the formation of a conventional dark region (see FIG. 1 ).

2 to 8, the light diffusing lens 1 according to the first embodiment includes a lower surface 100, an incident surface 200 through which light is incident, and light incident through the incident surface 200. It may include an exit surface 300 that is emitted.

Here, the light diffusing lens 1 may diffuse light incident through the incident surface 200 by using the aspherical incidence surface 200 and the exit surface 300. In addition, the exit surface 300 may include a pair of side surfaces 320 and 330 disposed to face the upper surface 310 and each other.

In addition, the light diffusion lens 1 may include a pair of corners 340 formed by the side surfaces 320 and 330 meeting. At this time, the corners 340 may be arranged to face each other in the long axis direction.

The light diffusing lens 1 may be formed using a material of polycarbonate or polymethacrylate. Here, the refractive index of the polycarbonate is 1.58, and the refractive index of the polymethmethylacrylate is 1.49.

The lower surface 100 may be disposed on the lower side of the upper surface 310. At this time, the lower surface 100 through the side surfaces 320 and 330 may be spaced apart from the upper surface 310. Here,'upper side' and'lower side' are relative expressions, and unless otherwise defined below, the direction from the lower surface 100 to the upper surface 310 is defined as the upper side (upper), and vice versa. In 310), the direction toward the lower surface 100 is determined as the lower side (downward).

The lower surface 100 may be formed in a convex or planar shape toward the lower side. At this time, the lower surface 100 having a convex shape toward the lower side may be a curved surface having a predetermined curvature.

The lower surface 100 is formed as a curved surface having a convex shape in the downward direction as an example, but is not limited thereto. For example, the lower surface 100 may have a plane formed from the edge to a predetermined length in the center direction, and a lower convex surface may be formed from the point where the plane ends to the center side. That is, the lower surface 100 has a curvature of 0 for a certain length from the edge to the center direction, but may be a shape in which the curvature increases from the predetermined length or more to the center and then decreases again.

Compared with the lower surface composed of only the flat surface, in the case of the lower surface 100 having the lower convex surface, light emitted from the light source to the lower side may be totally reflected to the upper side.

Here, the plane disposed on the lower surface 100 so that the light is preferentially reflected by the lower convex surface is preferably disposed outside the lower convex surface.

As illustrated in FIG. 4, the lower surface 100 may be formed in a rugby ball shape in which a circular inlet 210 is disposed in the center, but is not limited thereto. For example, the lower surface 100 may be formed in an elliptical shape having a long axis and a short axis.

The incident surface 200 is a portion of the surface from which light emitted from the light source located at the entrance 210 is incident into the light diffusing lens 1.

The incident surface 200 may be formed concave from the center of the lower surface 100 to the inside. Accordingly, the entrance port 210 may be formed in the center of the lower surface 100. In addition, a light source for irradiating light toward the incident surface 200 may be disposed in the entrance port 210.

An air layer may be disposed between the light source and the incident surface 200. Therefore, in the case of the light emitted from the light source to the air layer, the refractive index of the light diffusing lens 1 having a different refractive index may be further refracted.

2, 7 and 8, the incident surface 200 includes a first region 220 formed in a planar circle and a second region 230 concavely formed inward from the first region 220. It can contain.

The first region 220 may be disposed under the second region 230. In addition, as the first region 220 is formed in a cylindrical shape, the entrance sphere 210 may also be formed in a circular shape. Accordingly, the entrance sphere 210 may have a predetermined radius based on the optical axis C. In addition, the light source may be disposed at the center of the entrance port 210.

Light emitted from the light source to the side surfaces 320 and 330 may be incident on the first region 220.

The second region 230 may extend from the upper side of the first region 220. At this time, the second region 230 may be concave to the upper side so that the vertex P1 is formed on the optical axis C. 7 and 8, the second region 230 may include a curved surface. Further, the curved surface may be convex toward the optical axis C to have a predetermined curvature, but is not limited thereto. For example, the curved surface may be formed in an ellipse or a parabolic shape.

The second region 230 may be located on the upper side of the light source. At this time, the absolute value of the tangential slope of the curved surface of the second region 230 may gradually decrease from the top to the bottom of the curved surface.

Here, although the incident surface 200 includes the first region 220 and the second region 230 having different shapes, for example, it is not limited thereto. For example, the vertical cross section of the incidence surface 200 may be formed in a hemispherical shape, a semi-elliptical shape, a rugby ball shape, or a parabolic shape. Accordingly, the incident surface 200 may be formed as an aspherical surface.

On the other hand, when viewed in the direction of the optical axis of the light source, the light diffusion lens 1 may be formed to have a long axis and a short axis on a plane. At this time, the height H1 of each of the first side surface 320 and the second side surface 330 of the light diffusion lens 1 is smaller than the height of the long axis direction H2. Here, the first side surface 320 and the second side surface 330 may be formed symmetrically with respect to the long axis.

2 to 4, when viewed from the optical axis C, the light diffusion lens 1 may be formed in a planar rugby ball shape.

As shown in FIG. 3, when viewed in the direction of the optical axis, the light diffusion lens 1 may include a short axis formed of a predetermined length Lx and a long axis formed of a predetermined length Ly. In detail, a short axis of the upper surface 310 of the emission surface 300 of the light diffusion lens 1 may be formed with a predetermined length Lx, and a long axis may be formed with a predetermined length Ly. At this time, the length (Ly) of the long axis is greater than the length (Lx) of the short axis. Therefore, the light diffusion lens 1 can increase the amount of light diffusion in the long axis direction.

Here, the long axis and the short axis of the light diffusion lens 1 are vertically arranged in a plane, and at an imaginary point where the long axis and the short axis meet, an optical axis C is disposed as shown in FIG. 3. . Accordingly, when viewed from the optical axis C, the light diffusion lens 1 may be formed symmetrically with respect to the long axis and the short axis.

The length of the long axis of the light diffusion lens 1 may be 1.1 times or more and 2.0 times or less of the length of the short axis. Here, the length (Ly) of the long axis of the light diffusing lens 1 may be referred to as the width of the light diffusing lens (1) with respect to the long axis direction, and the length (Lx) of the short axis of the light diffusing lens (1) ) May be referred to as the width of the light diffusion lens 1 with respect to the minor axis direction.

When the length of the long axis compared to the length of the short axis of the light diffusing lens 1 is less than 1.1 times, it is difficult to remove the above-described dark area, and when it exceeds 2.0 times, light uniformity and production efficiency are affected.

FIG. 9 is a view showing light distribution according to a long axis length compared to a short axis length of the light diffusion lens according to the first embodiment, and FIG. 9A shows light distribution when the short axis length and the long axis length of the light diffusion lens are the same. 9(b) shows light distribution when the major axis length of the light diffusion lens is shorter than 1.1 times, and FIG. 9(c) shows light distribution when the major axis length of the light diffusion lens is 1.1 times or more. Shows.

As shown in FIG. 9(a), when the short and long axes of the light diffusion lens are the same, the dark region (see FIG. 1) cannot be removed.

As shown in FIG. 9(b), even when the short axis length and the long axis length of the light diffusion lens are less than 1.1 times, the dark region (see FIG. 1) cannot be removed.

As shown in FIG. 9C, when the length of the long axis of the light diffusion lens 1 is 1.1 times or more of the length of the short axis, an asymmetrical light distribution may be formed to remove the dark region.

10 is a view showing the experimental results of the conventional light diffusing lens and the light diffusing lens according to the first embodiment, Figure 10 (a) is a view showing the experimental results of the conventional light diffusing lens, Figure 10 ( b) is a diagram showing the experimental results of the light diffusing lens according to the first embodiment.

Referring to FIG. 10, it can be seen that the light diffusion amount of the light diffusion lens 1 is increased in the long axis direction compared to the conventional lens 2.

As shown in FIG. 10B, the light diffusion lens 1 implements anisotropic light diffusion. Further, when comparing the area A1 of FIG. 10(a) and the area A2 of FIG. 10(b), the light diffusion lens 1 has an area A2 (edges in the long axis direction of the light diffusion lens 1). Is embodying even light.

The top surface 310 of the exit surface 300 may be formed in a shape recessed in the center direction from the edge. At this time, the upper surface 310 may be a convex curved surface projecting toward the upper side.

The upper surface 310 may reflect light refracted by the incident surface 200 to the side surfaces 320 and 330 and the corners 340. For example, among the light irradiated from the light source to the upper surface 310, light irradiated toward the long axis at a predetermined angle θ based on the optical axis C is refracted to the corner by the upper surface 310. Can be. Accordingly, the light diffusion lens 1 can prevent the generation of leakage light in the long axis direction. Here, the upper surface 310 may be referred to as a reflective surface.

Since the light diffusing lens 1 is made of a material having a higher density than air, it is possible to totally reflect light incident on the upper surface 310 at a predetermined angle θ based on the optical axis C. Here, the angle θ is an angle formed by the optical axis C and the light irradiated from the light source, and may be an acute angle, as shown in FIG. 11. Further, the angle θ is a virtual line connecting the upper edge with respect to the shortening direction of the side surfaces 320 and 330 and the center (optical axis vertex 11a) of the upper light emitting surface of the light source and the optical axis C. It may be an angle.

In addition, the angle θ may be 52.5 degrees or less. If the angle θ is more than 52.5 degrees and is incident on the upper surface 310 formed as a curved surface, light leakage may occur in the long axis direction.

11 is a view showing light diffusion in a long axis direction and a short axis direction of the light diffusion lens according to the first embodiment, and FIG. 11(a) is a leakage occurring in the short direction of the light diffusion lens according to the first embodiment FIG. 11B is a view showing effective light in which leakage light is prevented in the long axis direction of the light diffusion lens according to the first embodiment.

As shown in (a) of FIG. 11, leakage light is generated in the minor axis direction of the light diffusion lens 1. Here, the leakage light may mean light that is not irradiated to the side surfaces 320 and 330. In particular, the leakage light may mean light irradiated upward from the side surfaces 320 and 330.

Accordingly, as shown in the area A3 of FIG. 10B, light sag may occur in the minor axis direction of the light diffusion lens 1.

As shown in (b) of FIG. 11, the length of the upper surface 310 in the long axis direction of the light diffusion lens 1 is longer than that in the short axis direction, and the height is higher than that in the short axis direction. The leaked light is converted to effective light.

Accordingly, light is uniformly distributed as in the area A2 of FIG. 10B.

Referring to FIG. 11, the light diffusing lens 1 of the light irradiated below 52.5 degrees based on the optical axis C among the light irradiated on the upper surface 310 increases the leakage light toward the short axis direction. . That is, with respect to the light irradiated to the upper surface 310 at an angle of 52.5 degrees or less based on the optical axis C, the light diffusion lens 1 may reduce leakage light as it goes from the short axis direction to the long axis direction on a plane.

Therefore, the light diffusing lens 1 forms the upper surface 310 formed as a curved surface by adjusting the length Ly and height H2 in the long axis direction, thereby preventing the generation of leakage light in the long axis direction. have. In addition, the light diffusion lens 1 enlarges the coverage of light with respect to the long axis direction, and asymmetric light distribution can be derived by the expanded coverage.

The curved surface of the upper surface 310 may increase as the absolute value of the slope of the tangent line goes from the edge toward the optical axis C. In addition, since the length of the curved surface of the light diffusion lens 1 is longer than the length Lx in the short axis direction, the first side surface 320 and the second of the light diffusion lens 1 are longer. The height H1 of each of the side surfaces 330 is shorter than the height H2 of the long axes. Here, the height H2 in the long axis direction may be the height of the edge 340. Further, the reference for the height may be a lower edge of each of the lower surface 100 or the first side surface 320 and the second side surface 330.

At this time, the height of the short axis direction H1 of each of the first side surface 320 and the second side surface 330 is 0.5 or more and less than 1, compared to the height of the long axis direction H2. That is, the height H1 of each of the first side surface 320 and the second side surface 330 may be formed within a range of 0.5*H2 ≤ H1 <1*H2.

When the height in the minor axis direction H1 is less than 0.5 times the height in the major axis direction H2, leakage light may be generated in the first side surface 320 and the second side surface 330, and the height in the short axis direction H1 is When the height is equal to the height H2 in the long axis direction, a light transmission phenomenon may occur for light irradiated below 52.5 degrees from the upper surface 310 based on the optical axis C.

In addition, the curved surface of the upper surface 310 may be formed to have a predetermined curvature (1/R1). Referring to FIGS. 7 and 8, the curvature (1/R1) of the long axis direction and the short axis direction The curvature (1/R1) may be the same. At this time, the center of the curvature (1/R1) may be disposed outside the light diffusion lens (1).

That is, the upper surface 310 is formed to be rotationally symmetrical with respect to the optical axis C, but may be formed in a longer shape in the long axis direction. Here, the curvature of the upper surface 310 may be referred to as a first curvature. Therefore, the upper surface 310 may be formed to have a narrower radius and a recessed shape toward the optical axis C.

It is exemplified that the curved surface of the upper surface 310 is formed to have a predetermined curvature, but is not limited thereto. For example, the curved surface may be formed in a part shape of a parabola or an ellipse.

The side surface disposed between the lower surface 100 and the upper surface 310 may include a first side surface 320 and a second side surface 330.

The first side surface 320 and the second side surface 330 may be disposed to face each other with the optical axis C interposed therebetween. At this time, the first side surface 320 and the second side surface 330 may be formed in parallel with the optical axis (C).

At this time, the height of the short axis direction H1 of each of the first side surface 320 and the second side surface 330 is smaller than the height of the long axis direction H2.

Accordingly, a first side portion 321 of the first side surface 320 may be disposed in the short axis direction, and a second side portion 331 may be disposed on the second side surface 330. Accordingly, the height H1 in the short axis direction of the first side surface 320 and the second side surface 330 may be the height of the first side portion 321 and the second side portion 331.

In addition, the height (H1) in the minor axis direction of the first side surface 320 and the second side surface 330 is the height of the vertex P2 which is a point of the upper surface 310 disposed on the optical axis C line ( H3). At this time, the height (H1) of the first side surface 320 and the second side surface 330 in the short axis direction (H1) is the height (H3) of the vertex (P2), which is one point of the upper surface 310 disposed on the optical axis (C) line. ) May be 2.8 to 3.0 times. Preferably, the height (H1) of the first side surface 320 and the second side surface 330 in the minor axis direction (H3) is the height (H3) of the vertex (P2), which is one point of the upper surface 310 disposed on the optical axis (C) line. ).

Since the height H3 of the vertex P2 which is one point of the upper surface 310 is disposed on the optical axis C line, it can be formed at a constant height regardless of the long axis direction and the short axis direction.

In addition, as the height H3 of the vertex P2 is adjusted, an increase in the slope with respect to the tangent of the upper surface 310 formed as a curved surface may be adjusted. Accordingly, the height H1 in the short axis direction of the first side surface 320 and the second side surface 330 may also be adjusted in consideration of the height H3 of the vertex P2.

Accordingly, in consideration of total reflection and light transmission by the upper surface 310, the height of the short axis direction H1 of the first side surface 320 and the second side surface 330 is disposed on the optical axis C line. It may be formed to be 2.8 to 3.0 times the height (H3) of the vertex (P2) which is one point of the surface 310.

Meanwhile, as the height H1 of the first side surface 320 and the second side surface 330 is smaller than that of the height H2 of the corner 340, as illustrated in FIG. 6, The first side surface 320 and the upper side of the second side surface 330 may be formed to have a predetermined curvature (1/R2). Here, the curvature (1/R2) may be referred to as a second curvature.

3 and 4, the first side surface 320 and the second side surface 330 may be formed to be convex outward in a plane. Here, the outer side means the opposite direction of the direction toward the optical axis C. Accordingly, the first side surface 320 and the second side surface 330 may include an outwardly convex curved surface. In addition, the curved surfaces of the first side surface 320 and the second side surface 330 may be formed to have a predetermined curvature.

In addition, the centers of curvature of each of the first side surface 320 and the second side surface 330 may be arranged to be spaced apart from the optical axis C on a plane. At this time, the center of curvature of the first side surface 320 may be formed on the second side surface 330 side, and the center of curvature of the second side surface 330 may be formed on the first side surface 320 side. Therefore, the light diffusion lens 1 may include a pair of corners 340 formed by meeting the first side surface 320 and the second side surface 330.

Referring to FIG. 12, the light source 10 irradiating light toward the incident surface 200 may include an upper light emitting surface 11 and four side light emitting surfaces 12. Accordingly, the light source 10 may implement five-sided light emission. At this time, the lower surface of the light source 10 may be disposed to contact the upper surface of the substrate 20.

Light irradiated from the upper light emitting surface 11 of the light source 10 is irradiated in the optical axis direction (z direction), and light irradiated from the side light emitting surface 12 is irradiated in the radial direction of the light diffusing lens 1 Can be.

In addition, an optical axis vertex 11a may be formed at the center of the upper light emitting surface 11. At this time, the optical axis vertex 11a may be disposed on the optical axis C line.

Here, an LED may be used as the light source 10. Also, a yellow phosphor may be applied to the LED.

Taken together, the light diffusion lens 1 includes the long axis and the short axis on a plane, and increases the length of the upper surface 310 formed as a curved surface in the long axis direction compared to the short axis direction, and at the same time, the side surfaces 320 and 330. ), the height H2 in the long axis direction may be larger than the height H1 in the short axis direction. Accordingly, the light diffusion lens 1 uses the upper surface 310 formed as a curved surface to totally reflect light incident therein to the edge 340 side.

Accordingly, the light diffusion lens 1 may increase light diffusivity in the long axis direction by the upper surface 310 whose length is increased in the long axis direction. Accordingly, the light diffusion lens 1 can prevent or minimize the presence of leakage light that may occur in the long axis direction side.

2nd Example

13 is a perspective view showing a light diffusing lens according to a second embodiment, FIG. 14 is a plan view showing a light diffusing lens according to a second embodiment, and FIG. 15 is a bottom view showing a light diffusing lens according to a second embodiment , Fig. 16 is a front view showing the light diffusing lens according to the second embodiment, Fig. 17 is a side view showing the light diffusing lens according to the second embodiment, and Fig. 18 is an upper part of the light diffusing lens according to the second embodiment 19 is a cross-sectional view of the minor axis direction with respect to the surface, and FIG. 19 is a cross-sectional view of the long axis direction with respect to the upper surface of the light diffusion lens according to the second embodiment. Here, FIG. 18 is a cross-sectional view showing line A1-A1 in FIG. 14, and FIG. 19 is a cross-sectional view showing line B1-B1 in FIG. In Fig. 13, the x-direction is the minor axis direction of the exit surface, the y-direction is the major axis direction of the exit surface, and the z-direction indicates the optical axis direction.

13 to 19, the light diffusing lens 1a according to the second embodiment includes a lower surface 100a, an incident surface 200 through which light is incident, and light incident through the incident surface 200. It may include an exit surface (300a) that is emitted. Here, the bottom surface (100a) and the top surface (310a) of the exit surface (300a) is a light diffusing lens (1) according to the first embodiment in that it is formed in an oval shape when viewed from the optical axis direction Have

The light diffusing lens 1a may diffuse light incident through the incident surface 200 using the aspherical incidence surface 200 and the exit surface 300a. In addition, the exit surface 300a may include an upper surface 310a and one side surface 350. Here, the light diffusing lens 1 according to the first embodiment includes a pair of corners 340 formed by meeting the side surfaces 320 and 330, so that it is formed in a rugby ball shape when viewed in the optical axis direction. , In the case of the light diffusing lens 1a according to the second embodiment, the light diffusing lens 1 according to the first embodiment rounds a pair of corners 340 formed by the side surfaces 320 and 330 meeting. It is formed in an oval shape.

The lower surface 100a may be disposed on the lower side of the upper surface 310a. At this time, the lower surface 100a through the side surface 350 may be arranged to be spaced apart from the upper surface 310a.

As illustrated in FIG. 15, the lower surface 100a may be formed in an elliptical shape in which a circular inlet 210 is disposed in the center.

On the other hand, when viewed in the optical axis direction of the light source, the light diffusion lens 1a may be formed to have a long axis and a short axis on a plane. At this time, the height H1 in the short axis direction of the side surface 350 of the light diffusion lens 1a is smaller than the height H2 in the long axis direction.

14, when viewed in the optical axis direction, the light diffusion lens 1a may include a short axis formed of a predetermined length Lx and a long axis formed of a predetermined length Ly. In detail, a short axis of the upper surface 310a among the exit surfaces 300a of the light diffusion lens 1a may be formed with a predetermined length Lx, and a long axis may be formed with a predetermined length Ly. At this time, the length (Ly) of the long axis is greater than the length (Lx) of the short axis. Therefore, the light diffusion lens 1a can increase the amount of light diffusion in the long axis direction.

Here, the long axis and the short axis of the light diffusion lens 1a are vertically arranged in a plane, and at an imaginary point where the long axis and the short axis meet, an optical axis C is disposed as shown in FIG. 14. .

The top surface 310a of the exit surface 300a may be formed in a shape recessed from the edge toward the center. At this time, the upper surface 310a may be a convex curved surface projecting toward the upper side. As shown in FIG. 5, the light diffusing lens 1 according to the first embodiment may have a vertex formed by an edge 340, but as shown in FIG. 16, light diffusing according to the second embodiment The vertex of the lens 1a may be deleted by a rounding process.

At this time, the upper surface 310a may reflect light refracted by the incident surface 200 to the side surface 350.

Therefore, the light diffusion lens 1a forms the upper surface 310a formed as a curved surface by adjusting the length Ly and height H2 in the long axis direction, thereby preventing the generation of leakage light in the long axis direction. have. Accordingly, the light diffusion lens 1a enlarges the coverage of light with respect to the long axis direction, and can derive an asymmetric light distribution by the expanded coverage.

The side surface 350 disposed between the lower surface 100a and the upper surface 310a may be symmetrically formed based on the long and short axes. At this time, the side surface 350 may be formed parallel to the optical axis (C).

Although described above with reference to embodiments of the present invention, those skilled in the art can variously modify the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that you can change it. And, it should be interpreted that the differences related to the modifications and changes are included in the scope of the present invention defined in the appended claims.

1, 1a: light diffusing lens
100, 100a: lower surface
200: entrance surface 210: entrance
300, 300a: exit surface
310, 310a: upper surface 320, 330, 350: side surface
321: first side 322: second side
C: Optical axis

Claims (10)

Lower side;
An incident surface concavely formed from the lower surface to the inside; And
Light incident through the incident surface is emitted and includes an exit surface including a long axis and a short axis on a plane,
The exit surface is
The upper surface formed of a curved surface,
It includes a first side surface and a second side surface disposed to face each other between the upper surface and the lower surface,
A light diffusing lens having a height in the minor axis direction H1 of each of the first side surface and the second side surface is smaller than the height in the long axis direction H2. According to claim 1,
Further comprising an edge formed by the first side surface and the second side surface meet,
The corners facing each other in the long axis direction are light diffusing lenses arranged parallel to the optical axis. According to claim 2,
A light diffusing lens in which an absolute value of the tangential slope of the upper surface with respect to the curved surface increases from the edge toward the optical axis. According to claim 3,
A light diffusing lens in which light irradiated toward the long axis at a predetermined angle (θ) based on the optical axis among the light irradiated on the upper surface is refracted to the corner by the upper surface. The method of claim 4,
The angle (θ) is 52.5 degrees or less light diffusing lens. According to claim 1,
A light diffusion lens having a height in the minor axis direction H1 of each of the first side surface and the second side surface is greater than or equal to 0.5 and less than 1 compared to the height in the long axis direction H2. The method of claim 6,
The first side surface and the upper side end portion of the second side surface is formed to have a predetermined curvature light diffusion lens. The method of claim 6,
The light diffusing lens is 2.8 to 3.0 times the height (H3) of the vertex (P2) which is one point of the upper surface disposed on the line of the optical axis (C), the height (H1) of the first side surface and the second side surface in the minor axis direction. . According to claim 1,
The length of the long axis is 1.1 times or more of the length of the short axis light diffusing lens. According to claim 1,
The lower surface is a light diffusion lens formed in an oval shape.

Images