KR20060127672A - Led lens structure capable of providing uniform upward illumination, led module and backlight apparatus incorporating the same - Google Patents

Abstract

An LED lens structure for uniform upward illumination, and an LED module and a backlight device employing the same are provided to disperse light, advancing from an inner lens to an outer lens, from a vertical axial line to the outside in the radial direction, thereby realizing uniform upward illumination. An LED lens structure for uniform upward illumination includes an upper hemispherical inner lens(110) receiving an LED chip(C) inside, and an outer lens(120) surrounding the inner lens. The LED chip is positioned in a concave portion of the inner lens. The outer lens has an inner surface formed with fine scattering patterns(130) at a predetermined area with respect to an axial line(A), which is perpendicular to the surface of the inner lens securing the LED chip, and a focus of the LED chip is disposed on the axial line. Therefore, light(L1,L2), which is generated in a focus of the LED chip and advancing from the inner lens to the outer lens in the predetermined range with respect to the axial line(A), is uniformly emitted to the peripheries of the axial line.

Description

LED LENS STRUCTURE CAPABLE OF PROVIDING UNIFORM UPWARD ILLUMINATION, LED MODULE AND BACKLIGHT APPARATUS INCORPORATING THE SAME}

1 is a cross-sectional view showing an example of a conventional side-emitting type LED lens used in an LCD backlight device.

FIG. 2 is a cross-sectional view illustrating an example of a backlight device employing an LED having the lens of FIG. 1.

3 is a cross-sectional view of the LED lens structure according to the present invention.

4 is a cross-sectional view illustrating an operation of equalizing light in the lens structure of FIG. 3.

FIG. 5 is a perspective view illustrating various examples of the fine protrusion pattern employed in the lens structure of the present invention separately from the lens structure.

6 is a cross-sectional view showing an LED module employing a lens structure according to the present invention.

7 is a graph comparing the light emission pattern of the lens structure according to the present invention and the light emission pattern of the conventional lens.

8 is a cross-sectional view of a modification of the LED lens structure according to the present invention.

9 is a cross-sectional view illustrating an operation of equalizing light in the lens structure of FIG. 8.

10 is a cross-sectional view showing an example of a backlight device employing an LED module according to the present invention.

11 is a cross-sectional view showing another example of a backlight device employing an LED module according to the present invention.

<Explanation of symbols of main parts in drawings>

110: internal lens 120: external lens

128: convex portion 130: protrusion pattern

F: focus of LED chip

The present invention relates to an LED lens, an LED module and a backlight device including the same. More specifically, the present invention provides an LED lens structure and LED module including the LED lens structure that can provide uniform upward illumination by spreading the light traveling from the inner lens to the outer lens within a predetermined range from the vertical axis to the radial outward from the vertical axis. And a backlight device.

As the electronic device industry develops, liquid crystal displays (LCDs) are attracting attention as next generation display devices. Since the LCD does not spontaneously generate light, it usually has a backlight module or device that generates light on the back of the LCD panel.

1 is a cross-sectional view showing an example of a conventional side-emitting type LED lens used in an LCD backlight device.

Referring to FIG. 1, the lens 10 disclosed in the document is divided into an upper portion having a reflecting surface 12 and a first refractive surface 14 and a lower portion having a second refractive surface 16. In addition, when viewed in three dimensions, the optical axis A has a symmetrical shape.

In this lens, the light L1 emitted at the focal point F of the LED chip (not shown) is reflected on the reflecting surface 12 to be emitted to the outside through the first refractive surface 14 or directly to the second refractive surface 16. Is emitted to the outside through.

However, some light L2 is not reflected to the outside through the first refracting surface 14 but is reflected internally and emitted upward through the reflecting surface 12. This light L2 generates unwanted noise in the illumination using the LED.

In order to prevent the unwanted light L2, that is, noise from being projected upward, the reflective paper 20 may be attached to the upper surface of the lens 10. In this way, the light emitted to the upper portion of the lens 10 is completely blocked to easily implement side emission.

However, since the connection portion between the lens 10 and the reflective paper 20 is formed at the upper end of the reflective surface 12, the area is narrow and the adhesive strength is weak. Thus, some form of package 10 needs to be modified for smooth and stable adhesion.

In addition, such reflective paper attachment requires a sophisticated manual work of the operator and difficult to automate, which increases the manufacturing time and cost of the backlight device. Moreover, the attached reflective paper is likely to fall off, degrading the reliability of the backlight device.

In addition, the lens 10 described above has a disadvantage in that molding is difficult. That is, it is difficult to precisely form internal peaks P formed by connecting the connecting portion 18 and the reflecting surface 12 that connect between the first refractive surface 14 and the second refractive surface 16 through molding. Lines may be formed on the surface of the lens 10, such as 18 or its periphery.

In addition, when the resin is filled in the recess R which receives the LED chip indicated by the focal point F, further work for preventing bubbles is required. That is, the LED chip is mounted on a substrate (not shown), the substrate is coupled with the lens 10 so that the LED chip is positioned in the recess R of the lens 10, and then a transparent resin is injected into the recess R. . However, in this case, the resin is not completely filled in the recess R, and there is a risk of bubbles. Therefore, there is a need for additional work, such as removing bubbles through the air outlet, as well as the risk of deterioration of the optical properties of the LED package due to bubbles remaining in such additional work.

2 is a cross-sectional view showing an example of a backlight device employing an LED having the lens described above.

The backlight device 30 of FIG. 2 is also commonly referred to as a direct type backlight device, and includes a flat reflector 32, a plurality of LED modules 34 disposed on the reflector 32, and the LED module 34. A reflective sheet 36 and a transparent plate 38 disposed at a predetermined distance G1 from the reflective sheet 36, and a liquid crystal panel (G2) at a predetermined interval G2 from the transparent plate 38. 40) is arranged.

In this case, the LED module 34 employs the lens 10 of FIG. 1 as described above, and the reflective paper 36 is also substantially the same as the reflective paper 20 of FIG. 1.

On the other hand, the lights L1 and L2 are emitted from the module 34 in the lateral or planar direction. Among them, the light L1 is reflected by the reflecting plate 32 and passes through the upper transparent plate 38 to provide a backlight to the liquid crystal panel 40 on the upper side. The other light L2 strikes the underside of the transparent plate 38 so that some L21 enters into the transparent plate 38 to provide a backlight to the liquid crystal panel 40 thereon. On the other hand, the other part L22 of the light L2 is reflected from the transparent plate 38 to the reflecting plate 32 and then reflected from the reflecting plate 32 through the transparent plate 38 in the same manner as the light L1. The backlight is provided to the liquid crystal panel 40.

Since the backlight device 30 having the above structure can install a plurality of bar-shaped LED modules 34 under the liquid crystal panel 40, there is an advantage that the backlight can be effectively provided to the large screen LCD.

However, since the predetermined distance G1 is required between the LED module 34 and the transparent plate 38 and the transparent plate 38 and the liquid crystal panel 40 must also be maintained at the predetermined interval G2, The backlight device 30 has a disadvantage that the thickness is increased.

In detail, since the light L generated by the LED module 34 is mainly reflected upward through the light blocking plate 36, the dark dark portion DA covered by the light blocking plate 36 is formed. In order to remove the dark part DA and the bright line, the transparent plate 38 and the liquid crystal panel 40 are mixed with each other until the light passes through the transparent plate 38 and enters the liquid crystal panel 40. There should be enough space (G2) more than a certain value between).

As described above, in order to make the light propagating from the reflecting plate 32 to the liquid crystal panel 40 as a whole to be uniform, the above-described distances G1 and G2 must be maintained at a predetermined value or more. Increasing thickness is inevitable.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to uniformly spread light radially outward from the vertical axis from the vertical axis to a range within the predetermined range from the vertical axis. The present invention provides an LED lens structure capable of providing an upward illumination and an LED module including the lens structure.

Another object of the present invention is to provide a backlight device that can minimize the thickness by employing an LED module having the lens structure described above.

In order to achieve the above object of the present invention, the present invention includes an upper hemispherical inner lens for accommodating the LED chip therein; And an outer lens surrounding the inner lens, the inner lens of the outer lens to scatter light traveling from the inner lens to the outer lens within a predetermined range about an axis perpendicular to the surface on which the LED chip is placed. By forming a fine scattering pattern on the surface, it is characterized in that to provide an LED lens structure for uniformly emitting light generated from the LED chip around the axis.

In the LED lens structure, the scattering pattern is characterized in that the uneven structure.

In the LED lens structure, the scattering pattern is formed in a predetermined range around the axis on the inner surface of the external lens.

In the LED lens structure, the inner surface of the outer lens coincides with the outer surface of the inner lens, the outer surface of the outer lens is characterized in that consisting of the upper surface and the cylindrical surface extending downward from the sphere. In this case, it is preferable that the outer lens has a thick portion between the spherical surface and the cylindrical surface to form an annular convex portion. Moreover, it is preferable that the said cylindrical surface spreads upwardly about the said axis line.

In the LED lens structure, the inner lens is characterized in that the recessed portion is formed in the portion accommodating the LED chip.

In addition, the present invention to achieve the above object of the present invention is the above-described LED lens structure; The LED chip disposed inside the inner lens; A substrate coupled to the lens structure with the LED chip seated thereon; And a terminal for connecting the LED chip to an external power source.

The LED module may further include a transparent resin encapsulating the LED chip inside the inner lens.

In addition, the present invention in order to achieve the above object of the present invention; It provides a backlight device comprising the above-described LED module arranged in a plurality on the top surface of the bottom plate to uniformly send light to the other side of the bottom plate.

In the backlight device, the LED module may further include a transparent resin encapsulating the LED chip inside the inner lens.

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

3 is a cross-sectional view of the LED lens structure according to the present invention, Figure 4 is a cross-sectional view for explaining the function of equalizing the light in the lens structure of FIG.

As shown in FIG. 3, the LED lens structure 100 according to the present invention includes an inner lens 110 having an upper hemisphere and an outer lens 120 covered by the inner lens 110.

The inner lens 110 is in the shape of an upper hemisphere with its bottom seated on a plane (not shown), and has a hollow recess R inside. LED chip C is arrange | positioned in this recessed part R, and focal point F of LED chip C is arrange | positioned so that the axis A perpendicular | vertical to the mounting plane of LED chip C may pass. In addition, the internal lens 110 is composed of a spherical upper portion 112 and a cylindrical lower portion 114, preferably has a uniform thickness as a whole.

The outer lens 120 is disposed to cover the inner lens 110. In this case, the external lens 120 may be disposed around the internal lens 110 at predetermined intervals or may be in physical contact with the internal lens 110.

The inner surface 122 of the outer lens 120 is formed to coincide with the outer surface of the inner lens 110. On the other hand, the outer surface of the external lens 120 is composed of a spherical upper outer surface 124 and a cylindrical outer surface 126. At this time, the upper outer surface 124 of the outer lens 120 is preferably farther from the inner lens 110 in the radial direction from the axis (A) to form a ring-shaped convex portion 128 at the edge.

In addition, the minute protrusion pattern 130 is formed in a predetermined region of the inner surface 122 of the external lens 120, specifically, a predetermined region around the axis A. FIG. The fine protrusion pattern 130 scatters the light L1 and L2 passing through as shown in FIG. 4 so that the light L1 and L2 are uniformly spread radially outwardly about the axis A. As shown in FIG.

This fine protrusion pattern 130 is preferably formed in the form of concentric circles, for example, around the axis A. As shown in FIG. That is, when the fine mountains and valleys are formed concentrically, it is possible to spread the light passing uniformly radially. In addition, the smaller the dimension of the pattern 130, the more evenly it can spread the light. Therefore, the smaller the height of the mountain (that is, the depth of the valley) is better, but considering the workability, about 70 to 300 µm is preferable.

On the other hand, the fine projection pattern 130 is not necessarily a protrusion or serration (serration) form. For example, it is also possible to form a scattering layer by coating a corresponding region of the inner surface 122 of the outer lens 120. Such a scattering layer may be formed by printing a metal at minute widths and intervals, or may be formed by depositing fine particles. In addition, it may be formed by applying a scattering material such as SiO ₂ , TiO ₂ in the form of fine particles.

Referring to FIG. 4, among the lights generated at the focal point F of the LED chip C, the lights L1 and L2 traveling upwardly adjacent to the axis A are spread out radially outwardly by the pattern 130. At this time, as described above, since the pattern 130 is formed to have a minute dimension, the lights L1 and L2 are spread with uniform illuminance.

Meanwhile, the other lights L3 and L4 converge toward each other while passing through the convex portion 128 of the external lens 120. Specifically, light L3 is refracted in a direction away from axis A, and light L4 is refracted toward axis A and emitted. That is, it can be seen that the convex portion 128 performs a convex lens function.

In addition, it can be seen that the light L5 passing through the cylindrical lower portion 114 of the inner lens 110 is also refracted toward the axis A when emitted from the outer lens 120.

As described above, the lens structure 100 of the present invention allows the light emitted upward about the axis A to be uniformly radially spread, but the light emitted laterally is refracted toward the axis A. Therefore, the light generated from the LED chip C is uniformly emitted as a whole around the axis A. FIG.

In other words, since the outer lens 120 is a concave lens structure that forms a convex portion 128 having a thick edge when viewed about the axis A, light passing through the outer lens 120 is concentrated toward the edge. Therefore, while reducing the intensity of the light propagating adjacent to the axis A, the illuminance on the edge side can be reinforced to make the illuminance uniform throughout.

5 is a perspective view illustrating various examples of the fine protrusion patterns 130 employed in the lens structure 100 of the present invention separately from the lens structure.

As shown in FIG. 5, examples of the projection patterns include the sawtooth protrusion patterns 130a of FIG. 5A, the sinusoidal protrusion patterns 130B of FIG. 5B, and the valleys of FIG. 5C. There are various types such as the flat serrated protrusion pattern 130c, the sinusoidal protrusion pattern 130d of which the valleys of FIG. 5 (d) are flat, and the serrated protrusion pattern 130e of which the hills and valleys of FIG. 5 (e) are flat. have. Besides these, many forms which can achieve the objective of this invention can be employ | adopted suitably.

6 is a cross-sectional view showing an LED module employing a lens structure according to the present invention.

Referring to FIG. 6, in the LED module according to the present invention, the heat transfer unit 152 and the terminals 154 and 156 are mounted on the substrate 150, and the LED chip C is mounted on the heat transfer unit 152. At this time, the LED chip C is electrically connected to the terminals 154 and 156 by, for example, a wire (not shown). On the other hand, the terminal 154 is integrally formed with the heat transfer unit 152 to perform a function of drawing heat from the LED chip C to a heat sink (not shown). Of course, the terminal 154 may perform only a heat transfer function, and the LED chip C may be connected to a power source by installing another terminal (not shown) together with the terminal 156.

Meanwhile, the lens structure 100 of the present invention is mounted on the substrate 150 while accommodating the LED chip C and the heat transfer part 152 in the recess R of the internal lens 110. At this time, Preferably, the recessed part R is filled with transparent resin, such as silicone and an epoxy.

In such an LED module, the LED chip C to which electricity is supplied emits light, and the generated light is uniformly emitted to the outside of the lens structure 100 in the pattern shown in FIG. 4.

7 is a graph comparing the light emission pattern of the lens structure according to the present invention and the light emission pattern of the conventional lens.

First, an LED chip having an output of 1 lumen was applied to the lens structure 100 of the present invention shown in FIG. 4, and illuminance was measured at a distance of 25 mm. The measured roughness was shown by the solid line in the graph of FIG. 7, and the full width half maximum (FWHM) was 80 mm.

On the other hand, the conventional lens structure was selected as the same as that of Figure 4 but the uneven pattern 130 is not formed, the illuminance was measured at a distance of 25mm. The measured roughness is shown by the dotted line in the graph of FIG. The illuminance of the conventional lens structure shows a high illuminance of about 360 lux about the center, that is, the axis A, but it can be seen that the illuminance drops sharply away from the center. That is, it provides extremely non-uniform illumination upwards.

Thus, it can be seen that, unlike the prior art which provides nonuniform illumination upwards, uniform illumination is achieved upwards by the present invention.

8 is a cross-sectional view of a modification of the LED lens structure according to the present invention, and FIG. 9 is a cross-sectional view illustrating an operation of equalizing light in the lens structure of FIG. 8.

Referring to FIG. 8, the LED lens structure 100-1 according to a modification of the present invention is the LED of FIG. 3 except that the lower outer surface 126-1 of the external lens 120 is open upward. It is substantially the same as the lens structure 100. Therefore, the same reference numerals are given to the same parts, and description thereof will be omitted.

In this way, as shown in FIG. 9, when the light L5 passes through the outer lens 120, the inclination of the lower outer surface 126-1 causes the convex portion 128 to be more oriented than in FIG. 4. It is refracted toward axis A. This configuration can improve the efficiency of the lens structure 100-1 by bringing more light beams toward the axis A. FIG.

10 is a cross-sectional view showing an example of a backlight device employing an LED module according to the present invention.

As shown in FIG. 10, the backlight device employing the LED module according to the present invention includes a flat bottom plate 150, a plurality of LED modules 100 and C disposed on the bottom plate 150, and the LED module. And a transparent plate 152 on the upper side of the chamber 100. The transparent plate 152 is disposed at a predetermined distance G3 from the LED lens structure 100. In addition, the liquid crystal panel 160 is disposed at a predetermined interval G4 from the transparent plate 152. The bottom plate 150 is preferably configured as a reflector plate, and the light reflected directly from the LED module 100 or C or by the transparent plate 152 to be projected onto the bottom plate 150 again is the transparent plate 152. Can be reflected toward).

In this way, the light generated from the LED chip C enters the transparent plate 152 at a predetermined angle α around the axis A. As shown in FIG. At this time, the light within this range proceeds to a uniform illuminance as described above with reference to FIG. Therefore, since the illuminance of light incident from the lower portion to the transparent plate 152 and the liquid crystal panel 160 thereon is uniform, the backlight device according to the present invention can properly perform the function of the surface light source.

On the other hand, since the backlight device of the present invention does not use the reflective paper 36, unlike the backlight device 30 shown in FIG. 2, the dark portion DA does not occur. Therefore, the gap G2 for eliminating the dark portion DA is not necessary, so that the gap G4 between the transparent plate 152 and the LCD panel 160 above it can be minimized or eliminated. In this way, the thickness of the backlight device can be reduced, thereby meeting the market demand of thinning.

11 is a cross-sectional view showing another example of a backlight device employing an LED module according to the present invention.

As shown in FIG. 11, the backlight device according to the present invention may omit the transparent plate unlike the configuration of FIG. 10. This is possible by emitting light upward from the LED module 100 (C) at a predetermined angle β about the axis A so that light of uniform intensity is incident on the predetermined area of the LCD panel 160. That is, the light emitted upward through the LED lens structure 100 of the present invention may be configured to have a uniform illuminance in a state of traveling by a predetermined distance (d).

As such, if the transparent plate is omitted, an advantage of reducing the weight occupied by the transparent plate as well as reducing the thickness as described with reference to FIG. 10 may also be obtained.

As described above, the present invention provides an LED lens structure and an LED module employing the same to provide uniform upward illumination by spreading the light traveling from the inner lens to the outer lens within a certain range from the vertical axis radially outward from the vertical axis. Can be. In addition, it is possible to minimize the thickness of the backlight device by employing the LED module having the lens structure described above. In addition, the weight of the device can be reduced by omitting the transparent plate from the backlight device.

Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art may vary the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be understood that modifications and variations can be made.

Claims (11)

An upper hemispherical inner lens for accommodating the LED chip therein; And An outer lens surrounding the inner lens, the inner lens of the outer lens to scatter light traveling from the inner lens to the outer lens within a predetermined range about an axis perpendicular to the surface on which the LED chip is placed; By forming a fine scattering pattern, LED lens structure, characterized in that for uniformly emitting light generated from the LED chip around the axis. The LED lens structure of claim 1, wherein the scattering pattern has an uneven structure. The LED lens structure of claim 1, wherein the scattering pattern is formed within a predetermined range around the axis on the inner surface of the external lens. The LED lens structure according to claim 1, wherein an inner surface of the outer lens coincides with an outer surface of the inner lens, and an outer surface of the outer lens is formed of an upper spherical surface and a cylindrical surface extending downward from the spherical surface. 5. The LED lens structure according to claim 4, wherein the outer lens has a portion between the spherical surface and the cylindrical surface thickened to form an annular convex portion. 5. The LED lens structure according to claim 4, wherein the cylindrical surface is spread upwardly about the axis. The LED lens structure of claim 1, wherein the internal lens has a recess formed in a portion accommodating the LED chip. The LED lens structure of any one of Claims 1-7; The LED chip disposed inside the inner lens; A substrate coupled to the lens structure with the LED chip seated thereon; And LED module comprising a terminal for connecting the LED chip to an external power source. The LED module of claim 8, further comprising a transparent resin encapsulating the LED chip inside the inner lens. Bottom plate; A backlight device comprising the plurality of LED modules of claim 8 arranged on an upper surface of the bottom plate so as to uniformly send light to the other side of the bottom plate. The backlight device of claim 10, wherein the LED module further comprises a transparent resin encapsulating the LED chip inside the inner lens.

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