WO2014051308A1 - Led illuminating lens and illuminating device using same and applied to backlight unit - Google Patents

Description

LED lighting lens and lighting device applied to the backlight unit using the same

The present invention relates to an illumination lens for an LED (LED) and a lighting device applied to the backlight unit using the same, and more particularly, easy to manufacture, minimizing tolerances during assembly, and slimming of the backlight unit structure, The present invention relates to a lighting lens for LED (LED) capable of realizing light weight and to providing a uniform light distribution and a backlight device using the same.

As the electronics industry develops, liquid crystal displays (LCDs) are attracting attention as next generation display devices. Since the liquid crystal display does not spontaneously generate light, the liquid crystal display generally includes a backlight unit that generates light on the back of the LCD panel.

Recently, the LED light source is mainly used as the light source of the backlight unit, and its application range is gradually expanded as the display device becomes slim, large, and high brightness.

In general, an LED (Light Emitting Diode) light source is a photoelectric conversion element that emits light using a junction structure of a P-type semiconductor and an N-type semiconductor as a semiconductor light source, and has a feature that light emitted from the light source is emitted. According to the present invention, light of various wavelengths can be obtained, and small size, long life, and low power consumption are used as compared to the conventional light source, and thus it is utilized as various display elements or next generation alternative lighting sources.

As a light emitting device using such an LED as a light source, for example, in Patent Publication No. 2009-15854, as shown in FIG. 1, an illumination lens 10 is disposed on the side from which light of the LED 1 is emitted. . The illumination lens 10 is configured as a concave surface whose slope is reduced when the shape of the first lens surface 2a is less than 60 ° in a specific condition and the optical axis, and the shape of the second lens surface 2b is The surface adjacent to the concave shape is characterized by a double structure having a convex shape when spaced apart from the optical axis by a certain distance, and the LED (1) through the prism shape or wrinkle processing on the base 2c of the first lens surface. It is characterized in that the light emitted from the light source is suppressed from directly incident to the bottom portion.

However, in the related art, as described above, since the second lens surface 2b has a dual structure, there is a problem that the mold manufacturing of the lens is very difficult.

In addition, there is a problem that the symmetry of the beam shape is misaligned when the error of the optical axis is misaligned when mounted to the LED light source, which adversely affects the quality and reliability of the entire device.

In order to solve the above problems, in the present invention, it is formed in a simple structure of a general lens shape, not only easy to manufacture a mold, but also has a degree of freedom to reduce the error in the configuration when mounted on the LED light source LED lighting lens The purpose is to provide.

In addition, an object of the present invention is to provide an illumination device capable of providing a uniform light distribution in the front surface of the backlight unit by configuring the illumination lens applied to the LED backlight unit such as a flat panel display.

In the present invention to achieve the above object, in the LED illumination lens for emitting light emitted from the LED light source at a constant emission angle, provided in the upper portion of the receiving portion for receiving the LED light source is emitted from the LED light source A first lens surface having an arbitrary ellipse shape in which light is incident and two focal points exist on the optical axis Z, and an agent having an arbitrary aspherical shape for emitting light incident through the first lens surface. An LED illumination lens comprising a two lens surface, wherein the shape Z which is spaced apart from the optical axes of the first lens surface and the second lens surface is determined by the following equation.

Where h is the radius, C is the center of curvature, K is the conical constant, and A ₄ to A ₁₀ are lens surface coefficients.

In the present invention, the second lens surface is characterized in that the light incident through the first lens surface by the Fesnel reflection to focus on the base portion of the first lens surface to form a conjugate point with respect to the LED light source.

Here, the base portion of the first lens surface may be formed in a plane or may be formed as a curved surface having a three-dimensional shape for diffusing and reflecting the focused light focused on the second lens surface.

The curved surface may be formed by continuously forming recesses having a predetermined size in a lattice form.

In the present invention, the two focal points of the first lens surface may have a value between −1 <K <−0.5 as a factor limiting the elliptical image.

In addition, the second lens surface may include a vertical surface formed from the base of the first lens surface to a predetermined height H, and an aspherical surface having an arbitrary curvature radius R, and the vertical surface H and the radius of curvature ( R) may be made at a ratio of | R |> H.

The light reflected by the Fresnel from the second lens surface may be focused on the base of the first lens surface.

Further, the refractive power P of the illumination lens composed of the first lens surface and the second lens surface satisfies the condition -5 <P <-1.

On the other hand, in order to achieve the above object in the present invention, in the LED illumination lens for emitting light emitted from the LED light source at a constant emission angle, provided in the upper portion of the receiving portion for receiving the LED light source in the LED light source A first lens surface having an arbitrary circular curvature radius in which the emitted light is incident and the center point of the circle exists on the optical axis Z, and an arbitrary aspherical surface for emitting the light incident through the first lens surface. A shape Z including a second lens surface having a shape, and spaced apart from an optical axis of the first lens surface and the second lens surface, is determined by the following equation. Can be.

Where h is the radius, C is the center of curvature, K is the conical constant, and A ₄ to A ₁₀ are lens surface coefficients.

In addition, in order to achieve the above object, in the present invention, there is provided an illumination device in which the above-described LED illumination lens is configured as an illumination light source of the backlight unit by an array configuration on a fixed panel.

Here, the LED illumination lens of the array may be set within a change range of the luminance distribution of about ± 20% based on the light diffusion distance (FWHM).

The present invention is configured as described above is easy to manufacture the product, can not only minimize the tolerance in the assembly, but also can realize the slimmer, lighter weight of the backlight unit structure, and also has the advantage of increasing the degree of freedom of product configuration have.

In addition, it is possible to diffusely reflect the light from the LED light source while minimizing the loss of light due to reflection on the lens surface, to provide a uniform light distribution when applied to various types of array type, and array the illumination lens without any additional deformation It is possible to apply lens for type lighting.

1 is a cross-sectional view showing an LED illumination lens according to the prior art.

2 is a cross-sectional view showing an embodiment of the LED illumination lens according to the present invention.

3 is a cross-sectional view illustrating a light scattering line in the LED illumination lens of FIG. 2.

4 is a cross-sectional view showing another embodiment of the LED illumination lens according to the present invention.

FIG. 5 is a diagram for illustrating the distribution of light reaching the liquid crystal display when the LED illumination lens of the present invention is used.

6 is a diagram illustrating a case in which the LED illumination lens of the present invention is applied as an array type.

FIG. 7 is a light distribution diagram illustrating a luminance distribution of light reaching a liquid crystal display when an LED illumination lens is used according to the present invention.

8 is a light distribution diagram showing a luminance distribution of light by a one-dimensional array type illumination lens using the LED illumination lens according to the present invention.

In the LED illumination lens of the present invention, in the LED illumination lens for emitting light emitted from the LED light source at a constant exit angle, the light emitted from the LED light source is provided above the receiving portion for receiving the LED light source And a first lens surface having an arbitrary ellipse shape in which two foci exist on the optical axis Z, and a second lens surface having an arbitrary aspherical shape in order to emit light incident through the first lens surface. The shape Z which is spaced apart from the optical axes of the first lens surface and the second lens surface is determined by the following equation.

Where h is the radius, C is the center of curvature, K is the conical constant, and A ₄ to A ₁₀ are lens surface coefficients.

Hereinafter, a preferred embodiment of the LED illumination lens according to the present invention with reference to the accompanying drawings in detail as follows.

[First Embodiment]

2 is a cross-sectional view showing an embodiment of the LED illumination lens according to the present invention, Figure 3 is a cross-sectional view showing a light scattering line in the LED illumination lens of FIG.

In the present invention, the LED light source (1) as a light emitting element, and is provided to cover the periphery of the LED light source 1, the LED illumination lens for emitting light emitted from the LED light source 1 at a predetermined exit angle (20) ).

The illumination lens 20 is made of a transparent acrylic (synthetic resin) or plastic material, and has a shape of rotational symmetry around the optical axis Z of the light emitted from the LED light source 1.

The direction of the optical axis Z refers to the direction vertically upward from the LED light source 1, and refers to the traveling direction of the light at the center of the three-dimensional output light flux of the light emitted from the LED light source 1.

The illumination lens 20 changes the direction of the light (L) emitted from the LED light source 1, the illumination lens 20 in the present invention is provided above the receiving portion for receiving the LED light source (1) The first lens surface 22 to which light emitted from the LED light source 1 is incident, and the second lens surface 24 having an arbitrary aspherical shape for emitting light incident through the first lens surface 22. ).

The first lens surface 22 is formed to have an elliptic shape in which two focal points P1 and P2 exist on the optical axis Z.

That is, in the illumination lens 20 of the present invention, the first lens surface 22 to which light is incident is formed in an ellipse shape, and the focal points P1 and P2 of the ellipse are present on the optical axis Z. Will be.

In addition, the second lens surface 24 is for finally emitting light emitted from the light source 1 to the front, and is provided on the front surface of the illumination lens 20 to receive light that is directly refracted by the light source 1. In addition to diverging, the diffused reflection from the bottom surface is refracted in the optical axis (Z) direction to minimize the light loss, and has a rotational symmetry with respect to the optical axis (Z), easy to reduce processing and assembly tolerance It is.

Here, the expression representing the surface shape of the first lens surface 22 and the second lens surface 24 is determined by Equation 1 below.

Shape Z is spaced apart from the optical axis of the first lens surface and the second lens surface,

[Equation 1]

Where h is the radius, C is the center of curvature, K is the cone constant, and A ₄ to A ₁₀ are lens surface coefficients.

Here, K is -1 <K <0: prolate ellipse,

K = -1: parabola.

In the present invention, the second lens surface 24 has an aspherical surface shape, and light incident through the first lens surface 22 by Fesnel reflection is focused on the base portion 26 of the first lens surface 22. A conjugation point is formed with respect to the said LED light source 1 so that it may become.

Here, the base of the first lens surface 22 may be formed in a plane.

In the present invention, the two focal points P1 and P2 of the first lens surface 22 may have a value between −1 <K <−0.5 as a factor limiting the shape of the ellipse. According to the embodiment of the present invention, as shown in Table 1 below, when the angle 130, the K value is -0.80, when the angle 140, the K value is -0.98, the first lens in the present invention The two focal points P1 and P2 of the face 22 are factors limiting the shape of the ellipse, wherein the K value has a value between -1 <K <-0.5.

In addition, the second lens surface 24 is an aspherical surface 24a having a vertical surface 24b formed from a base portion 26 of the first lens surface 22 to a predetermined height H, and an arbitrary curvature radius R. )

Here, the vertical surface 24b and the curved surface 24a may be formed at a ratio of R | H.

As described above, in the illumination lens 20 of the present invention, the light L reflected by the Fresnel from the second lens surface 24 is focused on the base 26 of the first lens surface 22, as shown in FIG. 3. .

In addition, the refractive power P of the illumination lens including the first lens surface 22 and the second lens surface 24 satisfies a condition of P <−1. More preferably, the refractive power P satisfies the condition -5 <P <-1. This means that the shape of the lens in which the first lens surface 22 and the second lens surface 24 are combined has the shape of a concave lens. Due to the above range, the illumination lens of the present invention has a uniform light distribution. It has the best conditions to achieve.

Moreover, the illumination device provided with the same can be provided using the illumination lens which concerns on this embodiment.

5 is a view showing a light divergence angle when the distance to the liquid crystal display panel is 20 mm when the illumination lens of the present invention is applied.

When the illumination lens 20 is used as a backlight for a liquid crystal display device, as shown in FIG. 5, a uniform light distribution is displayed on the liquid crystal display panel 100.

The illumination lens described above may be configured as a plurality of arrays and applied to the illumination lens.

That is, as shown in FIG. 6, the illumination lens 20 of the present invention may be configured as an illumination light source of the backlight unit by an array configuration in a fixed panel.

Here, when the illumination lens 20 is configured in an array type according to the divergence angle, the number of array lenses is determined according to the degree of divergence angle, and has a uniform light distribution.

In addition, the illumination lens according to the present invention can be applied to the illumination to further emit the incident light of the LED light source, it can be applied to the illumination device of the backlight unit of various display devices by the array configuration of the various types using the illumination lens.

Here, the LED illumination lens of the array is preferably set within the range of the luminance distribution difference is about ± 20% based on the light diffusion distance (FWHM) the installation interval (I).

In the present invention, when a single illumination lens is applied to various types of array type (a plurality of illumination lenses are configured and applied) illumination lenses, each lens is separately diverged for controlling the light divergence angle (L) of the array type lens. The technical gist of the present invention is to provide an LED illumination lens with high ease of application without adjustment.

As an example according to the present invention, r values, K values, and A values of the first lens surface 22 and the second lens surface 24 according to the divergence angle are shown in Table 1 below.

Peak Intensity Beam Orientation Angle angle 130 angle 140 First lens surface Second lens surface First lens surface Second lens surface R -0.68 -9.9206 -0.52 -17.2439 K -0.80 +1.1305 -0.98 -0.8572 A4 + 3.6885E-4 + 2.6361E-4 A6 -5.4877E-5 -3.2612E-5 A8 + 1.6811E-6 + 6.4134E-7 A10 -1.9021E-8 -5.1714E-9

The illumination lens 20 according to the present invention can be applied as a single product or an array type, using a single illumination lens whose orientation angle is determined through the lens surface coefficient value, and using such a single lens of a linear or various shapes It can be used as a diffused light source of various lighting devices by configuring in an array form.

Meanwhile, the first lens surface 22 has an elliptical shape and has rotational symmetry with respect to the optical axis. The first lens surface 22 primarily dissipates the light emitted from the LED light source 1, and the second lens surface 24. The incident light is incident on the divergent light, and the incident divergent light has an aspheric concave structure to make the divergent light even more, and has a structure of focusing light by Fresnel reflection on the base portion 26 of the first lens surface.

The second lens surface 24 has a structure that continuously changes without rotational symmetry and inflection point with respect to the optical axis.

Therefore, the light emitted from the LED light source 1 is incident on the first lens surface 22 and is further diverged and the diverged light is refracted by the second lens surface 24 and then diverged further and exits forward.

FIG. 7 is a light distribution diagram illustrating a luminance distribution of light reaching a liquid crystal display when a single LED illumination lens is used, wherein light emitted from a light source is emitted by a first lens surface and a second lens surface. It is possible to have a uniform luminance distribution in a wide area other than this locally focused shape.

8 is a light distribution diagram showing the brightness distribution of light by the one-dimensional array type illumination lens using the LED illumination lens according to the present invention, the light distribution in a plane with a luminance distribution difference within ± 20% apart from a certain distance from the lens As shown in FIG. 5, the array configuration can be used as an illumination light source of the backlight unit.

Second Embodiment

Another embodiment of the present invention will be described with reference to FIG. 4 as follows. In addition, the structure except having demonstrated in this embodiment is the same as that of said 1st Embodiment.

In another embodiment of the present invention, the illumination lens 30 includes a first lens surface 32 provided above the accommodating part accommodating the LED light source 1 and to which light emitted from the LED light source 1 is incident; It includes a second lens surface 34 having any aspherical shape for emitting light incident through the first lens surface 32. The first lens surface 32 is formed to have an elliptic shape in which two focal points P1 and P2 exist on the optical axis Z.

In addition, the second lens surface 34 is a vertical surface 34b formed from the base portion 36 of the first lens surface 32 to a predetermined height H, and an aspherical surface 34a having an arbitrary curvature radius R. )

The base portion 36 of the first lens surface 32 may be formed in a three-dimensional shape in order to diffusely reflect the focused light as a focusing surface of the Fresnel reflected light.

In the LED illumination lens 30 according to the second embodiment of the present invention, the base portion 36 of the first lens surface 32 is three-dimensional in order to diffusely reflect the focused light focused on the second lens surface 34. It may be formed as a curved surface of the shape.

The curved surface is preferably formed by a continuous groove in a predetermined size in the form of a lattice, in addition, it may be made through a continuous wrinkle processing or made in the shape of a groove.

As such, the base portion 36 of the first lens surface 32 is formed as a curved surface having a three-dimensional shape, thereby diffusing and reflecting the focused light focused on the second lens surface 34.

[Third Embodiment]

In the present invention, in the LED illumination lens for emitting light emitted from the LED light source at a constant emission angle, the arbitrary lens shape of the circular shape that the center of the circle is present on the optical axis (Z) the first lens surface on which light is incident It may be formed to have a radius of curvature.

That is, the illumination lens of the third embodiment of the present invention emits a first lens surface having a circular curvature radius in which a center point of a circle exists on the optical axis Z, and light incident through the first lens surface. In order to include a second lens surface having an arbitrary aspherical surface shape, and spaced apart from the optical axis of the first lens surface and the second lens surface, the form Z is determined by the following equation An illumination lens may be provided.

Where h is the radius, C is the center of curvature, K is the cone constant, and A ₄ to A ₁₀ are lens surface coefficients.

In the said 3rd Embodiment, since the structure of that excepting the above is the same as that of the said 1st Embodiment, the description is abbreviate | omitted.

Although described and shown in connection with a preferred embodiment for illustrating the principles of the invention, the invention is not limited to the configuration and operation as it is shown and described, but rather variously within the scope of the appended claims It may be changed.

Industrial Applicability The present invention is easy to manufacture a product, can minimize the tolerance in the assembly, can realize the slimmer, lighter weight of the backlight unit structure, and also has the advantage of increasing the degree of freedom of product configuration, industrial use It is a possibility invention.

Claims (15)

In the LED illumination lens for emitting light emitted from the LED light source at a constant exit angle,
A first lens surface provided above the accommodating part accommodating the LED light source and having an elliptic shape in which light emitted from the LED light source is incident, and two focal points exist on the optical axis Z;
A second lens surface having an aspherical surface shape for emitting light incident through the first lens surface;
And a shape Z spaced apart from the optical axes of the first lens surface and the second lens surface is determined by the following equation.

Where h is the radius, C is the center of curvature, K is the conical constant, and A ₄ to A ₁₀ are lens surface coefficients. The method according to claim 1,
And the second lens surface forms a conjugation point with respect to the LED light source by causing light incident through the first lens surface to be focused on the base of the first lens surface by Fesnel reflection. The method according to claim 1,
The base portion of the first lens surface is a planar or LED illumination lens, characterized in that formed in a curved surface of a three-dimensional shape for diffusing and reflecting the focused light focused on the second lens surface. The method according to claim 3,
The curved surface of the LED illumination lens, characterized in that the groove of a predetermined size is formed continuously in a lattice form. The method according to claim 1,
Two focal points of the first lens surface are factors limiting an elliptical image,
An LED illumination lens having a value in the range of -1 <K <-0.5. The method according to claim 1,
The second lens surface includes a vertical surface formed from the base of the first lens surface to a predetermined height (H), and an aspherical surface having an arbitrary curvature radius (R). The method according to claim 6,
The vertical surface (H) and the radius of curvature (R) is an LED illumination lens, characterized in that consisting of a ratio of | R |> H. The method according to claim 1,
The light reflected by the Fresnel from the second lens surface is focused on the base of the first lens surface, the illumination lens for the LED. The method according to claim 1,
An LED illumination lens, characterized in that the refractive power of the illumination lens consisting of the first lens surface and the second lens surface satisfies the condition -5 <P <-1. In the LED illumination lens for emitting light emitted from the LED light source at a constant exit angle,
A first lens surface disposed above the accommodating part accommodating the LED light source, the light incident from the LED light source is incident, and having a circular curvature radius in which a center point of the circle exists on the optical axis Z;
A second lens surface having an aspherical surface shape for emitting light incident through the first lens surface;
Wherein the shape Z spaced apart from the optical axes of the first lens surface and the second lens surface is determined by the following equation.

Where h is the radius, C is the center of curvature, K is the conical constant, and A ₄ to A ₁₀ are lens surface coefficients. The method according to claim 10,
The second lens surface has an aspheric shape, and the light incident through the first lens surface by the Fesnel reflection is focused on the base of the first lens surface to form a conjugate point with respect to the LED light source. LED light lens. The method according to claim 10,
The base portion of the first lens surface is a planar or LED illumination lens, characterized in that formed in a curved surface of a three-dimensional shape for diffusing and reflecting the focused light focused on the second lens surface. The method according to claim 12,
The curved surface of the LED illumination lens, characterized in that the groove of a predetermined size is formed continuously in a lattice form. An illumination device according to any one of claims 1 to 13, wherein the LED illumination lens is configured as an illumination light source of a backlight unit by an array configuration on a fixed panel. The method according to claim 14,
The LED illumination lens of the array is a lighting device, characterized in that the installation interval is the difference in luminance distribution ± 20% range based on the light diffusion distance.

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