Asymmetric diffusion lens for LED backlight unit

Abstract

The present invention relates to an asymmetric diffusion lens for a backlight unit, comprising: a diffusion part having an elliptical upper surface having a long axis and a short axis and a circular bottom surface; the groove accommodating part is arranged at the center of the bottom surface of the diffusion part and provides a space for accommodating an LED package; the incident surface is an interface between the groove accommodating part and the diffusion part; and an emission surface which is a side surface and an upper surface of the diffusion part.

Description

Technical Field

[0001] The present invention relates to an asymmetric diffusion lens for LED backlight units, and more specifically, to a lens for LED backlight units that enables miniaturization. Background Technology

[0002] Recently, in order to improve the price competitiveness of LED-based backlight units (BLUs), methods have been proposed to increase the output of individual LEDs and reduce the number of LEDs per unit area.

[0003] The light emitted by an LED is concentrated in the center compared to the surrounding area. Therefore, it cannot be evenly distributed to the periphery; instead, the front of the LED is brighter, and it becomes dimmer with distance from the front.

[0004] To address this issue, research is underway on diffuser lenses of various shapes to more effectively and uniformly diffuse the light generated from LEDs.

[0005] On the other hand, while it is necessary to symmetrically and uniformly diffuse the light emitted from the LED, it is also necessary to diffuse more light only in a specific direction by configuring the LED.

[0006] For example, the vertical LED spacing of the backlight unit is wider than the horizontal LED spacing, or vice versa. In the example described above, this asymmetrical LED spacing is used to increase LED output while reducing the number of LEDs.

[0007] If the LEDs are arranged with a denser horizontal spacing than vertical spacing, then a uniform light distribution can only be achieved by diffusing more light vertically and less horizontally.

[0008] An example of an asymmetric lens having asymmetric light distribution characteristics as described above is the lens described in Figure 15 of Patent No. 10-1861233 (Light Emitting Unit Array and Suitable Light Diffusing Lens, Granted May 18, 2018).

[0009] This type of lens forms a long strip-shaped light pattern on the target surface along an axis perpendicular to the central axis, thus the shape of the lens itself has the same shape as the desired light distribution pattern.

[0010] In addition, the incident and exit parts are both asymmetrical in shape, which makes the design difficult, makes it hard to miniaturize the lens, and increases costs. Summary of the Invention

[0011] (The problem to be solved)

[0012] The technical problem to be solved by the present invention is to provide an asymmetric diffusion lens for LED backlight units that is easy to design and conducive to miniaturization.

[0013] (Solutions)

[0014] The present invention for solving the technical problems described above includes: a diffuser having an elliptical upper surface with a major axis and a minor axis, and a circular lower surface; a recess receiving portion disposed at the center of the lower surface of the diffuser, providing space for accommodating an LED package; an incident surface being the interface between the recess receiving portion and the diffuser; and an ejection surface being the side surface and the upper surface of the diffuser.

[0015] In an embodiment of the present invention, when the tilt angle of the side extending along the long axis of the diffuser (the angle formed by the virtual vertical line extending upward from the bottom edge of the diffuser and the side) is a first tilt angle, and the tilt angle of the side extending along the short axis is a second tilt angle, the tilt angles of the other sides can be tilted at an angle between the first tilt angle and the second tilt angle.

[0016] In an embodiment of the present invention, the ratio of the second tilt angle to the first tilt angle may be greater than 1.1 and less than 1.8.

[0017] In an embodiment of the present invention, the upper surface of the diffuser may be recessed to maximize the center depth.

[0018] (The effect of the invention)

[0019] This invention provides asymmetric light distribution by adjusting the side tilt angle without changing the overall size of the lens, thus offering advantages such as ease of design and miniaturization. Furthermore, it reduces the manufacturing cost of asymmetric diffusion lenses. Attached Figure Description

[0020] Figure 1 This is a structural diagram of an asymmetric diffusion lens for an LED backlight unit according to a preferred embodiment of the present invention.

[0021] Figure 2 yes Figure 1 Sectional view of AA.

[0022] Figure 3 yes Figure 1 Cross-sectional view of the middle section (BB).

[0023] Figure 4 It is Figure 2 and Figure 3 Overlapping cross-sectional views.

[0024] Figure 5 This is a plan view of the present invention.

[0025] Figure 6This is a photograph illustrating the light distribution characteristics of the present invention.

[0026] Figure 7 and Figure 8 These are photographs showing the light distribution characteristics based on the ratio of the second tilt angle to the first tilt angle.

[0027] (Explanation of reference numerals in the attached diagram)

[0028] 11: Diffusion section 12: Incident surface

[0029] 13: Injection surface 14: Recessed receiving groove

[0030] 15a, 15b: Side view Detailed Implementation

[0031] To fully understand the structure and effects of the present invention, preferred embodiments are described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and with various modifications. However, this description of embodiments is provided to fully disclose the invention and to fully inform those skilled in the art of the scope of the invention. For ease of explanation, components are shown enlarged beyond their actual size in the drawings, and the proportions of individual components may be exaggerated or reduced.

[0032] The terms "first," "second," etc., may be used to describe various components, but the components shall not be limited to these terms. These terms are used only for the purpose of distinguishing one component from another. For example, "first component" may be named "second component" without departing from the scope of this invention, and similarly, "second component" may be named "first component." Furthermore, singular expressions include plural expressions unless explicitly stated otherwise in the text. Terms used in embodiments of this invention, unless otherwise defined, can be interpreted in the meaning known to those skilled in the art.

[0033] Hereinafter, an asymmetric diffusion lens for an LED backlight unit according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0034] Figure 1 This is a structural diagram of an asymmetric diffusion lens for an LED backlight unit according to a preferred embodiment of the present invention; Figure 2 yes Figure 1 Sectional view of AA in the middle; Figure 3 yes Figure 1 Cross-sectional view of the middle section (BB); Figure 4 It is Figure 2 and Figure 3 A diagram showing the overlapping of the cross-sectional outlines; Figure 5 This is a plan view of the present invention.

[0035] Refer to each Figures 1 to 5 According to a preferred embodiment of the present invention, an asymmetric diffusion lens 10 for an LED backlight unit includes: a diffusion portion 11, which is formed as a disk with a height smaller than its diameter; a groove receiving portion 14, which is disposed at the center of the bottom surface of the diffusion portion 11 and provides space for accommodating an LED package (not shown in the figure); an incident surface 12, which is the interface between the groove receiving portion 14 and the diffusion portion 11; and an ejection surface 13, which is the side surface and the top surface of the diffusion portion 11.

[0036] The top and bottom surfaces of the diffuser 11 are respectively elliptical and circular.

[0037] The structure and function of the preferred embodiments of the present invention as described above will be explained in more detail below.

[0038] First, the diffuser 11 actually constitutes the shape of the asymmetric diffuser lens 10 of the present invention, and diffuses the light incident through the incident surface 12 using various materials and shapes, so as to release the light through the exit surface 13 with an asymmetric light distribution.

[0039] The attached drawings show the upper ejection surface 13 as a recessed shape as an example of the diffuser 11, but a flat or convex shape can also be used.

[0040] However, the present invention is characterized in that, in order to provide a light distribution that is close to a right quadrilateral rather than a circular light distribution on a plane, as shown in the example in the figure, it is preferable to use a diffuser 11 with a groove shape on the upper emission surface 13.

[0041] This is because the light from the LED package incident through the incident surface 12 is released through the recessed upper emission surface 13 while being reflected to be released through the side emission surface 13.

[0042] As described above, since the upper surface of the diffuser 11 is elliptical and the lower surface is circular, the side surface connecting the elliptical upper surface and the circular lower surface has the characteristic of having different lengths and inclinations at each position.

[0043] exist Figure 2 In the middle, the first tilt angle Θ1 of the side 15a is characterized by being more than Figure 3 The second tilt angle Θ2 of the side 15b is smaller and the length is also shorter.

[0044] The first tilt angle Θ1 and the second tilt angle Θ2 are the angles formed by the virtual vertical line at the end of the bottom surface and the side surfaces 15a and 15b, respectively.

[0045] Figure 2 and Figure 3It is a cross-sectional view used to show the position of the second tilt angle Θ2 with the largest angle and the first tilt angle Θ1 with the smallest angle to clearly show the difference in tilt angles. The tilt angles of the sides of other regions are tilt angles with the angle between the first tilt angle Θ1 and the second tilt angle Θ2.

[0046] exist Figure 4 Lieutenant General Figure 2 and Figure 3 The cross-sectional views shown are superimposed to illustrate the characteristics of the invention, by Figure 5 The shape of the diffuser 11 of the present invention can be easily confirmed by the plan view.

[0047] refer to Figure 5 , Figure 2 This is a cross-sectional view of the major axis A of the ellipse-shaped diffuser 11. Figure 3 It is a cross-sectional view of the minor axis B of the ellipse.

[0048] The diameter of the regions other than the major axis A and the minor axis B has the length between the minor axis B and the major axis A, and the inclination angle of the side surface connected to the bottom surface of the circular diffuser 11 has an inclination angle between the first inclination angle Θ1 and the second inclination angle Θ2.

[0049] As described above, due to the difference in tilt angle of the sides, the light emitted through the sides of the diffuser 11 has different emission angles, and so on. Figure 6 The diagram illustrates the light distribution characteristics that form a near-long right-angled quadrilateral to one side.

[0050] With the light distribution characteristics described above, the LED package is suitable for backlight units 20 arranged with unequal spacing, which can form an overall uniform light distribution pattern.

[0051] exist Figure 6 In the example, the shape of the light distribution pattern can be changed according to the ratio of the upper major axis A to the minor axis B of the diffuser 11 or the ratio of the first tilt angle Θ1 to the second tilt angle Θ2.

[0052] The ratio of the second tilt angle Θ2 to the first tilt angle Θ1 can be defined by the following mathematical formula 1:

[0053] (Mathematical Formula 1)

[0054] 1.8>Θ2 / Θ1>1.1.

[0055] In the above mathematical formula 1, the ratio of the second tilt angle Θ2 to the first tilt angle Θ1 is used not only for the shape of the light distribution but also to prevent image quality degradation.

[0056] Figure 7 This is a photograph showing the light distribution pattern when the ratio of the second tilt angle Θ2 to the first tilt angle Θ1 is 1.1; Figure 8This is a photograph showing the light distribution pattern when the ratio of the second tilt angle Θ2 to the first tilt angle Θ1 is 1.2.

[0057] As from Figure 7 and Figure 8 It can be confirmed that 1.1 has a critical characteristic, and the desired light distribution pattern cannot be formed below 1.1.

[0058] In addition, at resolutions above 1.8, there are severe optical path differences in light emitted from the sides, which can lead to image quality degradation.

[0059] Therefore, preferably, the present invention limits the ratio of the first tilt angle Θ1 to the second tilt angle Θ2 to the range defined by the above mathematical formula 1.

[0060] As described above, a groove with its center at the lowest position can be formed on the upper part of the diffuser 11. Preferably, the upper part is elliptical and the groove on the upper part has a circular structure.

[0061] The structure described above can be achieved through Figure 2 and Figure 3 We can confirm this through comparison.

[0062] A cross-section showing the direction of the major axis A. Figure 2 The upper edge has a plane, as shown in the cross-section along the minor axis B. Figure 3 The groove described herein extends to the upper edge.

[0063] As described above, the groove on the diffuser of reflected and refracted light is made into a circle, thereby allowing light to diffuse regardless of the overall elliptical shape of the upper part.

[0064] The following describes embodiments of the present invention; however, these are merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments can be implemented therein. Therefore, the true scope of protection of the present invention should be defined by the scope of the claims.

Claims

1. An asymmetric diffusion lens for an LED backlight unit, comprising: The diffuser section has an ellipse with a major axis and a minor axis on the top and a circle on the bottom. A recessed receiving portion, disposed at the center of the bottom surface of the diffuser, provides space for accommodating an LED package; The incident surface is the interface between the groove receiving portion and the diffuser portion; and The ejection surface is the side and top of the diffuser.

2. The asymmetric diffusion lens for an LED backlight unit according to claim 1, characterized in that, When the tilt angle of the side extending along the long axis of the diffuser (the angle formed by the virtual vertical line extending upward from the bottom edge of the diffuser and the side) is the first tilt angle, and the tilt angle of the side extending along the short axis is the second tilt angle, the tilt angles of the other sides are tilted at an angle between the first tilt angle and the second tilt angle.

3. The asymmetric diffusion lens for an LED backlight unit according to claim 2, characterized in that, The ratio of the second tilt angle to the first tilt angle is greater than 1.1 and less than 1.

8.

4. The asymmetric diffusion lens for an LED backlight unit according to any one of claims 1 to 3, characterized in that, A groove is formed on the top of the diffuser, recessed to maximize the center depth.

5. The asymmetric diffusion lens for an LED backlight unit according to claim 4, characterized in that, The edge of the groove is circular.

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