WO2021256729A1

WO2021256729A1 - Diffusion plate-supporting type lens

Info

Publication number: WO2021256729A1
Application number: PCT/KR2021/006716
Authority: WO
Inventors: 함승우; 김지운; 고석채
Original assignee: 주식회사 에이치엘옵틱스
Priority date: 2020-06-19
Filing date: 2021-05-31
Publication date: 2021-12-23
Also published as: KR102152649B1

Abstract

The present relates to a diffusion plate-supporting type lens comprising: an upper surface including a concave upper reflective surface positioned in a center portion, a supporting surface positioned on the circumference of the upper reflective surface and being in parallel to an installation surface and thus in contact with a lower surface of a diffusion plate to support the diffusion plate, and an edge surface positioned on the circumference of the supporting surface; a side surface extending downwards from the tip of the edge surface of the upper surface; and a lower surface disposed to be parallel to the upper surface in a range defined by the side surface and including an incident surface in which light of LED is incident to the center thereof, and a lower reflective surface positioned on the circumference of the incident surface to re-reflect the light reflected by the upper reflective surface and cause the light to be incident to the diffusion plate through the supporting surface.

Description

diffuser plate supported lens

The present invention relates to a diffuser plate supported lens, and more particularly, to a diffuser plate supported lens capable of reducing the thickness of a backlight unit of a display device.

A backlight unit (BLU) using an LED applies a secondary lens individually to each LED for the purpose of light diffusion.

The lens applied to the LED backlight unit diffuses the emitted light of the LED so that it is incident on the incident surface of the diffusion plate.

In this case, most of the LED backlight units use a support pin that supports the diffusion plate and separates it from the lens in order to secure a sufficient optical distance.

For example, Patent Registration No. 10-2002546 (backlight unit for image generating device, registered on July 16, 2019) describes a support structure in which a lens and a diffusion plate are spaced apart and a side surface is a reflective surface.

As such, the conventional structure in which the diffuser plate is supported and spaced apart from the lens is characterized in that a sufficient optical distance can be secured to obtain uniform surface light emission.

However, it is necessary to reduce the thickness of the backlight unit according to the market demand for the reduction in the thickness of the display device, and according to this need, a method in which the diffuser plate directly contacts the lens has been proposed.

Patent Publication No. 10-2017-0013698 (a light diffusion lens, a backlight unit and a display including the same, published on February 7, 2017) discloses that in order to reduce an optical gap, the lens protrudes from the upper center of the lens. A lens is disclosed that further includes a diffuser plate support.

That is, a method of reducing the optical gap has been proposed by further including a diffuser plate support part protruding from the center of the upper surface of the existing lens and contacting the bottom surface of the diffuser plate to support the diffuser plate without using a support pin.

However, since the diffuser plate-supported lens of the prior art publication as described above further includes a diffuser plate support protruding from the top of the lens, it is difficult to see that the diffuser plate is actually supported directly by the lens, and the diffuser plate is directly supported by the lens. There is room for improvement as it has a larger optical gap compared to the structure being used.

In addition, since the lower surface of the diffusion plate is supported using a structure protruding from the center of the upper surface of the lens rather than the upper surface of the lens, the relatively thin diffusion plate support may be damaged and reliability may be deteriorated.

The reason for forming the support part of the protrusion structure in the center of the conventional diffuser plate-supported lens is that it is difficult to secure a sufficient optical distance when the diffuser plate directly contacts the upper surface of the lens. because it does

An object of the present invention to be solved in consideration of the above problems is to provide a diffuser plate-supported lens capable of stably supporting the diffuser plate using the upper surface of the lens and improving the diffusion uniformity.

In order to solve the above technical problems, the diffuser plate-supported lens of the present invention has a concave upper reflective surface located in the center, and a periphery of the upper reflective surface, which is parallel to the installation surface and in contact with the lower surface of the diffuser plate. A support surface for supporting the diffusion plate, an upper surface having an edge surface positioned around the support surface, a side surface extending downward from the edge surface end of the upper surface, and the side surface within the range defined by the side surface. It is arranged parallel to the upper surface, the light of the LED is incident on the center of the incident surface, and located around the incident surface to re-reflect the light reflected from the upper reflective surface to be incident on the diffusion plate through the support surface and a bottom surface having a lower reflective surface.

In an embodiment of the present invention, the edge surface may be a curved surface.

In an embodiment of the present invention, the bottom surface includes a first flat surface between the incident surface and the lower reflective surface, and a second flat surface between the lower reflective surface and the side surface, the lower reflective surface, A first reflective surface that is defined by a groove formed on the bottom and extends upward from the first flat surface to re-reflect light reflected from the upper reflective surface, and extends downward from the upper end of the first reflective surface. It may include a second reflective surface connected to the second flat surface.

In an embodiment of the present invention, a virtual first line segment connecting the contact point between the support surface and the edge surface from the contact point of the first reflective surface and the first flat surface, and the first reflective surface and the first flat surface Considering a second virtual line segment connecting the edge surface and the side contact point from the contact point of , the angle between the first line segment and the second line segment may be greater than 0 degrees and less than or equal to 15 degrees.

In an embodiment of the present invention, the incident surface extends from the central point, which is the center of the bottom surface, to the side surface, and the first surface of the upwardly convex curvature, and extends from the first surface to the side surface, the downwardly convex curvature may include the second side of

In an embodiment of the present invention, when the height from the installation surface to the central point is the minor radius, and considering an imaginary ellipse passing through the contact point of the first surface and the second surface, the first surface and the second surface are each It may be located outside the virtual ellipse.

In an embodiment of the present invention, the first surface includes a first incident surface on the central point side and a second incident surface on the second surface side based on the vertex of the convex curvature, and the first incident surface includes: It may be parallel to the installation surface or inclined by 5 degrees or less.

The lens of the present invention supports the diffuser plate with a relatively flat upper surface in contact with the lower surface of the diffuser plate, thereby making it more stable and increasing reliability.

In addition, according to the present invention, the optical gap can be further reduced by supporting the diffusion plate using the lens itself rather than a separate structure protruding from the upper surface of the lens, and thus the thickness of the backlight unit and the display device can be reduced.

In addition, the present invention has the effect of providing a uniform diffusion characteristic despite the disadvantage that the optical distance is short by directly supporting the diffusion plate with the lens by proposing a partial and unique shape of the lens.

1 is a top side perspective view of a diffuser plate supported lens according to a preferred embodiment of the present invention.

FIG. 2 is a bottom side perspective view of FIG. 1 ;

3 is a cross-sectional view of the front side of FIG. 1 .

4 is an installation state diagram of the present invention.

5 is a schematic diagram of light reflected by the upper reflective surface and the first reflective surface of the present invention.

6 is a light distribution simulation of the present invention.

7 and 8 are schematic views for explaining the characteristics of the curved edge surface of the present invention in comparison with the angled edge surface, respectively.

FIG. 9 is a light distribution simulation of FIG. 8 .

10 is another exemplary configuration diagram of the lower reflective surface.

11 is a light distribution simulation result of the lens in which θ is 16 degrees in FIG. 10 .

12 is a detailed cross-sectional configuration view of an incident surface.

* Explanation of symbols *

1: diffuser plate supported lens 2: substrate

3: diffuser plate 100: top surface

110: upper reflective surface 120: support surface

130: edge 200: side

300: bottom 310: entrance side

320: groove 330: lower reflective surface

340: first flat surface 350: second flat surface

In order to fully understand the configuration and effect of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be embodied in various forms and various modifications may be made. However, the description of the present embodiment is provided so that the disclosure of the present invention is complete, and to fully inform those of ordinary skill in the art to which the present invention belongs, the scope of the invention. In the accompanying drawings, components are enlarged in size from reality for convenience of description, and ratios of each component may be exaggerated or reduced.

Terms such as 'first' and 'second' may be used to describe various elements, but the elements should not be limited by the above terms. The above term may be used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a 'first component' may be termed a 'second component', and similarly, a 'second component' may also be termed a 'first component'. can Also, the singular expression includes the plural expression unless the context clearly dictates otherwise. Unless otherwise defined, terms used in the embodiments of the present invention may be interpreted as meanings commonly known to those of ordinary skill in the art.

Hereinafter, a diffuser plate supported lens according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.

1 is a perspective view of a lens according to a preferred embodiment of the present invention, FIG. 2 is a bottom side perspective view of FIG. 1, and FIG. 3 is a front side cross-sectional view of FIG.

1 to 3 , the diffuser plate supported lens 1 according to a preferred embodiment of the present invention is a single medium, and the upper surface 100 has a geometrically curved edge, and the side surface of the upper surface 100 A side surface 200 extending downward from the side 200 and a bottom surface 300 positioned parallel to the upper surface 100 in the lower portion of the side surface 200,

The upper surface 100 has a concave upper reflective surface 110 that primarily reflects the light of the LED incident from the lower surface 300 side in the center, and is disposed around the upper reflective surface 110 . As a flat surface, it includes a support surface 120 that is supported in contact with a bottom surface of a diffusion plate (not shown), and a corner surface 130 that is a curved surface connecting the side surface 200 from the circumference of the support surface 120 . do.

In addition, the bottom surface 300 is defined by the receiving groove 311 in which the LED is accommodated, the incident surface 310 on which the light of the LED is incident, and the incident surface 310 is spaced apart by a predetermined distance as the center. It is defined by the groove 320 and is disposed and includes a lower reflective surface 330 for re-reflecting the light reflected from the upper reflective surface (110).

Reference numeral 340 denotes a first flat surface between the incident surface 310 and the lower

reflective surface

330 , and 350 denotes a second flat surface between the lower reflective surface 330 and the side surface 200 .

Hereinafter, the configuration and operation of the diffusion plate supported lens 1 of the present invention configured as described above will be described in more detail.

First, the diffusion plate-supported lens 1 of the present invention reflects the light of the incident LED in a specific direction according to the geometric structure, diffuses it in the medium, and emits it through the upper surface 100 and the side surface 200 .

At this time, the diffuser plate-supported lens 1 of the present invention supports the bottom surface of the diffuser plate 3 on the top of the substrate 2 on which the LED is mounted, as shown in FIG. 4 .

Therefore, it is necessary to stably and reliably support the diffuser plate 3, and to have a uniform and controllable light distribution capable of providing uniform surface light emission through the diffuser plate 3 despite a short optical distance. it should be

The upper surface 100 of the diffuser plate-supported lens 1 of the present invention may be a square or rectangular shape in plan view, and the vertex portion is assumed to be a curved surface in order to prevent light aggregation.

Compared to a conventional lens having a conventional circular or elliptical top surface, the present invention has a structure with a short optical distance, and although the optical distance is short, when applied to a backlight unit in which LEDs are arranged in a grid type, a rectangular light distribution is provided so that dark spots do not occur. to have

The central portion of the upper surface 100 includes an upper reflective surface 110 having a structure that is lower in height toward the center where the LED is located on the lower side.

That is, the upper reflective surface 110 is a curved surface extending from the center 111 of the upper surface 100 to the boundary surface 112 located within a certain radius, and is a conical surface inverted up and down.

Outside of the boundary surface 112 , a flat support surface 120 is located horizontal to the ground (or installation surface). The support surface 120 is in contact with the bottom surface of the diffusion plate 3 , and can support the diffusion plate 3 relatively stably.

That is, since a partial area of the upper surface of the lens is used instead of a protruding structure compared to the conventional method, the area in contact with the diffusion plate 3 is increased, so that more stable support can be provided.

Light emitted through the diffuser plate 3 is directly incident on the diffuser plate 3 .

Another characteristic effect of the present invention of directly supporting the diffusion plate 3 by using the support surface 120, which is a flat surface of the upper surface 100, is that the thickness of the backlight unit can be further reduced compared to the prior art, and through this, the display device The overall thickness of the can also be reduced.

The edge surface 130, which is a boundary surface between the support surface 120 and the side surface 200, is assumed to be a curved surface. Features and actions of the curved edge surface 130 will be described later in more detail.

The bottom surface 300 has an upwardly concave incident surface 310 in its central portion, and the incident surface 310 has a shape defined by a receiving groove 311 for accommodating the LED.

The characteristics of the receiving groove 311 and the characteristic shape of the incident surface 310 defined by the receiving groove 311 will be described later in more detail.

A first flat surface 340 is positioned around the incident surface 310 , and the first flat surface 340 is assumed to be in close contact with the upper surface of the substrate 2 .

A lower reflective surface 330 whose shape is defined by a groove 320 is positioned around the first flat surface 340 .

The lower reflective surface 330 provides two reflective surfaces having different curvatures.

The first reflective surface 331 may be a curved surface, and the second reflective surface 332 may be a flat surface.

The first reflective surface 331 is a surface located closer to the incident surface 310 than the second reflective surface 332 , and the second reflective surface 332 from the interface with the first flat surface 340 . ) is a curved surface that slopes upward to the interface.

The first reflective surface 331 reflects a portion of the light reflected from the upper reflective surface 110 of the upper surface 100 and is emitted through the supporting surface 120 and the edge surface 130 of the upper surface 100 . .

As described above, the light emitted through the support surface 120 is directly incident on the diffusion plate 3 and is diffused.

At this time, in the absence of the first reflective surface 331 , it is difficult to emit light through the flat support surface 120 , and if light is not incident on the diffusion plate 3 through the support surface 120 , dark dark areas are This makes it impossible to provide uniform surface light emission.

In the present invention, the first reflective surface is used to generate light incident in a direction perpendicular to and close to the support surface 120 so that light emission can be made smoothly through the support surface 120 using the flat support surface 120 . (331) is provided.

5 is a schematic diagram of light reflected by the upper reflective surface 110 and the first reflective surface 331 of the present invention.

As shown in this figure, the light of the LED accommodated in the receiving groove 311 is incident to the medium of the lens through the incident surface 310 , and a portion of the incident light is reflected by the upper reflective surface 110 .

At this time, the path of the reflected light is downward along the direction away from the center, and is reflected again from the first reflective surface 331 .

The reflection path of the light reflected from the first reflective surface 331 is upward along a direction away from the center, and the re-reflected light reflected from the first reflective surface 331 is the support surface 120 and the edge surface 130 . ) is released through

At this time, the re-reflected light forms an angle of 90 degrees to 70 degrees with respect to the support surface 120 , and the light incident close to 90 degrees is emitted without being reflected by the support surface 120 , and the diffusion plate is in contact with the support surface 120 . (3) is entered.

Therefore, in the present invention, it is possible to form a uniform light distribution while directly supporting the diffusion plate 3 with the support surface 120 , which is parallel and flat to the installation surface (or the ground).

6 shows a light distribution simulation result of the present invention.

As shown in FIG. 6 , the present invention can form a light distribution pattern close to a quadrangle according to its shape, and has a characteristic that the luminance change from the center is made gradually.

That is, it is possible to provide a rectangular uniform light distribution pattern.

7 and 8 are schematic diagrams for explaining the characteristics of the corner surface 130, which is a curved surface of the present invention, in comparison with the angled corner surface, respectively.

Referring to FIG. 7 , a portion of the light reflected from the first reflective surface 331 is emitted to the upper diffuser plate 3 through the curved edge surface 130 , and at this time, uniformly over the edge surface 130 . By allowing one light to be emitted, it is possible to prevent light aggregation from being concentrated.

If the corner surface 130 is an angled surface instead of a curved surface as shown in FIG. 8 , the light incident on the diffuser plate 3 through the corner surface 130 and the light incident on the diffuser plate 3 through the side surface 200 . The generated light may partially overlap each other, and it is difficult to expect a uniform light distribution pattern due to the occurrence of light aggregation.

FIG. 9 is a diagram illustrating a simulation result of light distribution when the upper surface 100 and the side surface 200 are in contact with each other by an angled edge surface as shown in FIG. 8 .

As shown in this figure, light aggregation occurs in some parts, so that a part with high luminance is partially generated, and when the curved edge surface 130 is applied as in the present invention, a uniform light distribution pattern can be formed.

10 shows a lower reflective surface 330 of another embodiment of the present invention.

The lower reflective surface 330 of the present invention is divided into a first reflective surface 331 and a second reflective surface 332 as described above, and the first reflective surface 331 is the first reflective surface 331b based on the reference point 331b. It can be divided into a first curvature reflective surface 331a extending up to the flat surface 340 and a second curvature reflective surface 331c extending up to the second reflective surface 332 .

That is, the first reflective surface 331 may include a plurality of surfaces having different curvatures.

In particular, centering on the boundary point between the first reflective surface 331 and the first flat surface 340 , the first line segment (a) passing through the boundary point between the support surface 120 and the edge surface 130 and the first line segment (a) Considering the second line segment b passing through the boundary point between the first reflection surface 331 and the second reflection surface 332 , the angle θ between the first line segment a and the second line segment b is 0 It shall exceed 15 degrees and be less than 15 degrees.

This may be understood as limiting the cross-sectional length of the second curvature reflective surface 331c, which becomes a factor determining the shape of the first reflective surface 331 .

As θ approaches 0 degrees, the length of the second curvature reflective surface 331c decreases, and as θ increases, the length increases.

Such limitation of the shape of the first reflective surface 331 is a factor determining the amount of reflected light reflected from the first reflective surface 331 and emitted through the support surface 120 and the edge surface 130, A satisfactory light distribution characteristic result was obtained in the angular range limited to the above θ value.

11 shows simulation results for the case where the θ value is 16 degrees.

As shown in this figure, light aggregation occurs in some parts, so that areas with higher luminance than the center are generated, and thus uniform light distribution cannot be provided.

In addition, when the value of θ is 0 degrees, the boundary between the first reflective surface 331 and the second reflective surface 332 becomes a cusp in the cross-section, and the product reproducibility may be lowered due to the optical path characteristics that are difficult to specify at the apex. have.

12 is an enlarged cross-sectional view of a part of the incident surface 310 .

Referring to FIG. 12 , the incident surface 310 of the present invention has a special shape for providing an incident path suitable for a structure in which a part of the upper surface 100 is formed of a flat support surface 120 .

The incident surface 310 is configured to include a first surface 314 and a second surface 315 having different curvatures while going outward with respect to the central point 312 .

A height from the substrate 2 to the central point 312 of the incident surface 310 is defined as y.

Considering an ellipse with a minor radius of y and an unknown major radius of x, the first surface 314 is a surface convex upward based on the contact point 313 between the ellipse and the incident surface 310, and the second surface 315 is It becomes a convex face downward.

At this time, when both the first surface 314 and the second surface 315 are based on the above-described ellipse having a minor radius of y and a major radius of x, the first surface 314 and the second surface 315 are both ellipses. The curvature is determined so that it is located outside of .

In particular, the first surface 314 includes a first incident surface 314a close to the central point 312 with respect to the vertex and a second incident surface 314b opposite to the central point 312, and the first incident surface 314a is horizontal. On the surface close to the light, the light emitted in the vertical direction from the LED is incident, and is also incident in the vertical direction.

As such, the light incident through the first incident surface 314a is reflected again at the central portion of the upper reflective surface 110 described above, and then is re-reflected through the lower reflective surface 330 and diffused through the supporting surface 120 . It is incident on the plate (3).

Accordingly, since the amount of light incident on the diffusion plate 3 through the support surface 120 is finally determined by the shape of the first surface 314 , the first incident surface 314a is parallel to the installation surface or installed. It may be inclined within the range of 5 degrees from the plane.

As such, the present invention stably supports the diffusion plate using a relatively wide support surface, and uses the shape of the incident surface and the shape of the lower reflective surface of the bottom to inject a sufficient amount of light into the diffusion plate through the support surface. It becomes possible to form a uniform light distribution.

Although the embodiments according to the present invention have been described above, these are merely exemplary, and those of ordinary skill in the art will understand that various modifications and equivalent ranges of embodiments are possible therefrom. Accordingly, the true technical protection scope of the present invention should be defined by the following claims.

The present invention is more stable in supporting the diffuser plate by changing the structure of the lens supporting the diffuser plate using the laws of nature, and has industrial applicability as it can increase reliability.

Claims

A concave upper reflective surface located in the center, a support surface positioned around the upper reflective surface and parallel to the installation surface, in contact with the bottom surface of the diffuser plate to support the diffuser plate, and the support surface located around the support surface an upper surface having a corner surface;

a side surface extending downward from the edge surface end of the upper surface; and

An incident surface arranged parallel to the upper surface within a range defined by the side surface, on which the light of the LED is incident in the center, and the light reflected from the upper reflective surface located around the incident surface are re-reflected and the A diffuser plate-supported lens including a bottom surface having a lower reflective surface that is incident on the diffuser plate through the supporting surface.
According to claim 1,

The edge surface is a diffuser plate supported lens, characterized in that the curved surface.
3. The method of claim 2,

The bottom is

a first flat surface between the incident surface and the lower reflective surface, and a second flat surface between the lower reflective surface and the side surface,

The lower reflective surface includes a first reflective surface that is defined by a groove formed in the bottom surface and extends upward from the first flat surface to re-reflect light reflected from the upper reflective surface, and A diffuser plate supported lens including a second reflective surface extending downward from the top and connected to the second flat surface.
4. The method of claim 3,

An imaginary first line segment connecting the contact point of the support surface and the edge surface from the contact point of the first reflective surface and the first flat surface, and the edge surface from the contact point of the first reflection surface and the first flat surface Considering the imaginary second line segment connecting the contact points of the side surfaces,

An angle between the first line segment and the second line segment is greater than 0 degrees and less than or equal to 15 degrees.
5. The method according to any one of claims 1 to 4,

The incident surface is

A diffuser plate-supported lens extending from a central point that is the center of the bottom to the side surface, the first surface having an upwardly convex curvature, and a second surface extending from the first surface to the side surface and having a downwardly convex curvature .
6. The method of claim 5,

Considering an imaginary ellipse passing the contact point of the first surface and the second surface with the height from the installation surface to the central point as the short radius,

The first surface and the second surface are respectively located outside the virtual ellipse of the diffuser plate supported lens.
6. The method of claim 5,

The first side is

Based on the vertex of the convex curvature, comprising a first incident surface on the side of the central point and a second incident surface on the side of the second surface,

The first incident surface is a diffuser plate supported lens, characterized in that parallel to the installation surface or inclined at 5 degrees or less.