KR100765469B1 - Led package for optical efficiency - Google Patents

Abstract

An LED(Light Emitting Diode) package is provided to enhance photo efficiency of a light emitting device by obtaining enhanced light extraction capability and predetermined directivity from the LED package itself using an encapsulating member filled in a portion between an LED light source and a lens without an air gap between the encapsulating member and the lens. An LED package includes an LED light source(203), a lens and an encapsulating member. The lens(202) is located on an upper portion of the LED light source. The lens has a hole which is formed around the light axis of the LED light source. The encapsulating member(201) is filled in a predetermined portion between the LED light source and the lens through the hole. The diameter of the hole is in a range of 0.2 mm or more. The lens is made of a plastic material.

Description

LED package for improving light efficiency {LED PACKAGE FOR OPTICAL EFFICIENCY}

1 is a perspective view and a side view of an LED package according to an embodiment of the prior art.

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

Figure 3 is an exploded view of the components of the LED package according to an embodiment of the present invention.

4 to 6 are perspective and side views of the LED package according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100,200,300: Mold portion 101,201,301,401,501: Encapsulant

202,302,402,502: Lens 203,403,503: LED light emitting part

204,404,504: lead portion 410,510: substrate

The present invention relates to an LED package having improved light efficiency, and more particularly, a lens having an LED light source unit and a hole positioned above the LED light source unit and formed around an optical axis of the LED light source, and between the LED light source unit and the lens through the hole. It includes an encapsulant to be filled.

The present invention relates to an LED package which satisfies both the improvement of the light extraction efficiency and the directivity at the same time by configuring the blocking that can be filled with the encapsulation lens and the optimal design of the shape of the lens according to the required specifications.

Efforts to improve the luminous efficiency of LEDs continue to progress from chip to package.

In the package stage, it is possible to construct a thermally stable structure even when a relatively high current is applied using a material having good heat dissipation efficiency using a heat sink, or to increase the light extraction efficiency by an optimal design considering the optical structure and characteristics of the package. Efforts are underway.

However, much of this effort is gaining some effect at the laboratory level, and there are cases where it is difficult to apply it in the actual manufacturing process.

Therefore, there is a need for a proposal of a light emitting device that can be applied to a structure or cost cost competitiveness in an actual manufacturing process.

As a result, some development needs to be considered in consideration of the environment and purpose of use.

The best way to improve light extraction efficiency in LED packages is to create curvature in the shape of the encapsulation material to minimize the total amount of light emitted from the LED chip into the interior at the interface between the encapsulant and the air.

There is a known process equipment developed for this purpose, but the corresponding quality level is still not satisfactory, and the price of the equipment is also very expensive.

Most of the light emitting diodes are formed by filling an encapsulant in a cup-shaped mold part, wherein the encapsulant is formed almost close to a plane, and the amount of light that is dissipated in total reflection on the surface thereof is about 20-30%.

1 is a perspective view and a side view of an LED package according to an embodiment of the prior art.

The embodiment is an LED package filled with an encapsulant on the LED light source, and as shown in FIG. 1, the curvature and the height of the encapsulant may be slightly adjusted by adjusting the encapsulant discharge amount and curing time, but it is difficult to control the curvature and the height of a certain shape. .

Rather than forming the concave curvature in the form of shrinkage of the central portion rather than the shape as shown in FIG. 1, in this case, there is a problem that the relative decrease in light extraction efficiency is severe.

In an effort to improve such a problem, studies are being conducted to improve light extraction efficiency through micro patterning on the surface of an encapsulation layer formed near a plane.

In addition, efforts have been made to improve the light extraction efficiency by forming a natural weak curvature by adjusting the discharge amount and the curing time using a high viscosity sealing material.

However, the light extraction efficiency that can be improved by these efforts is usually between 5% and 10%. Therefore, considering the additional costs and processing time in the process, it is still difficult to apply in reality.

An object of the present invention has been made to solve the problems of the prior art as described above, using an optical lens in the LED package and manufacturing the outer shape of the optical lens in a curvature form to improve the light extraction efficiency, It is to provide a configuration of the LED package having a high light efficiency and a specific direction angle by having a convenience.

Another object of the present invention is to provide a light emitting device having high economical value added by improving the reliability of the electrical characteristics of the LED without having to spend a lot of additional cost or additional time in the process.

Still another object of the present invention is to provide a light emitting device having a configuration in which the height of the LED package is minimized so that the optical effect and the satisfaction of the design can be simultaneously obtained.

In order to achieve the above object, an LED package for improving light efficiency of the present invention includes a lens having an LED light source unit, a hole positioned on the LED light source unit and formed around an optical axis of the LED light source, and the LED light source unit and the lens through the hole. It includes an encapsulant filled in between.

In the present invention, the LED light source portion is installed in the mold portion or the substrate having a predetermined shape and is characterized in that it is electrically connected through the lead portion.

In the present invention, the LED light source is installed on the substrate is characterized in that it is fixed by any one of the guide hole, intaglio irregularities, embossed irregularities.

In the present invention, the diameter of the hole is preferably 0.2 mm or more and 2/3 or less of the total diameter of the lens.

In the present invention, preferably, the material of the lens includes a plastic material.

In the present invention, the shape of the lens is preferably selected from the group consisting of spherical surface, aspherical surface, composite aspherical surface, fresnel, diffractive lens (DOE), fly eye lens, lenticular lens. It is one shape.

In the present invention, preferably, the material of the encapsulation material is selected from the group consisting of epoxy-based and silicon-based materials.

In the present invention, the encapsulant further includes a phosphor.

In the present invention, the lens further comprises one or more air vent passage on the lower contact boundary surface.

In order to achieve the above object, a method of manufacturing an LED package for improving light efficiency of the present invention includes installing an LED light source inside a mold having a predetermined shape or on a substrate and electrically connecting the lead to a hole in the center of the lens. And mounting the lens on which the hole is formed so that the optical axis of the hole and the LED light source unit coincide with each other, and mounting the encapsulant through the hole of the lens.

In the present invention, the encapsulant is characterized in that it is filled so that no air gap is formed on the light path between the LED light source and the stove.

In the present invention, in the step of filling the encapsulant, preferably the encapsulant comprises a phosphor, or at the beginning of the encapsulant, the phosphor contains a phosphor but does not contain a phosphor when filling the hole of the lens.

In order to achieve the above object, a method of manufacturing an LED package for improving light efficiency of the present invention includes installing an LED light source inside a mold part having a predetermined shape or on a substrate and electrically connecting the lead light source, and an encapsulant including a phosphor. And enclosing the LED light source unit, forming a hole in the center of the lens, and fixing the lens on the encapsulant layer so that the optical axis of the hole and the LED light source unit coincide with and positioned on the LED light source unit. Filling the encapsulant through the hole of the more.

According to the present invention, in the construction of an LED package used in a light emitting device, a blocking that can be filled with an encapsulant may be configured as a lens in order to simultaneously improve the light extraction efficiency and satisfy the directivity characteristic, and optimize the shape of the lens according to the required specifications. The present invention proposes a configuration in which a rotationally symmetrical hole is formed in the center of the lens corresponding to the optical axis of the LED light source to easily fill the encapsulating material from the outside.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to the components of the following drawings, the same components, even if displayed on the other drawings to have the same reference numerals as possible, it is determined that the subject matter of the present invention may unnecessarily obscure Detailed descriptions of well-known functions and configurations will be omitted.

2 is a cross-sectional view schematically showing the structure of an LED package according to an embodiment of the present invention.

In the above embodiment, the LED package is provided with an LED chip 203 inside the mold portion which is recessed inwardly, and uses this as the LED light source portion.

On the upper part of the structure where the lead part 204 for the electrical connection of the LED light source unit 203 is fixed, a lens 202 having a hole centered on the optical axis of the light source generated in the LED light source unit is formed therein. It is installed.

The lens may be a hemispherical plastic injection lens, but is not necessarily limited thereto, and may be formed of a known lens shape and lens material which can be known to those skilled in the art.

The diameter of the hole penetrating the central portion of the lens is preferably at least 0.2 mm and not larger than at least 2/3 of the diameter of the entire lens.

Preferably the diameter of the hole is 1 to 2 mm.

The shape of the hole may vary, but a circular shape is preferable.

When observing the side cross-sectional view of the lens as shown in Figure 1 can be formed so as to be inclined more toward the lower surface from the upper surface of the lens, the hole diameter of the lens lower than the hole diameter of the top of the lens may be larger.

As the hole penetrating the central portion of the lens is larger, bubbles generated during the filling of the encapsulant 201 can escape again through the hole so that bubbles do not occur after the filling, but the excessively large hole is the present invention. There is a difficulty in forming the LED package.

That is, if the diameter of the hole of the lens exceeds 50% of the inner diameter of the mold portion 200, the sealing material is formed in the hole flat as the sealing material is filled through the hole, the light extraction efficiency according to the present invention is improved LED Difficult to be implemented as a package

Therefore, according to an embodiment of the present invention, in addition to the holes included in the lens, one or more air bleeding passages may be additionally formed at the portion where the lens is mounted, that is, at the lower boundary of the lens to prevent bubbles.

Referring to FIG. 2, the lens 202 may have an air bleeding passage at a portion in contact with the mold 200. However, in another embodiment of the present invention to be described below, since the lens may be fixed on the substrate, not the mold portion, the air bleeding passage may be formed at the portion in contact with the substrate.

The shape of the passageway can vary and a circle will be preferred.

However, even if an air bleeding passage is formed at the lower boundary surface of the lens, the encapsulant 201 is always filled through a hole formed in the central portion of the upper lens.

The encapsulant is preferably an epoxy-based material or a silicon-based material, but is not necessarily limited thereto, and a known material known to those skilled in the art may be used as the encapsulating material.

The degree of curvature, size, and shape of the lower surface of the lens are not limited to those shown in FIG. 2, and a known lens shape and size may be used.

That is, the light refractive direction change due to the difference in refractive index between the lens and the encapsulant and the shape in which the bubble does not occur may be changed to be optimized.

In one embodiment according to the present invention, a general spherical lens or an aspherical lens may be provided.

3 is an exploded view of representative components constituting the configuration of the LED package according to an embodiment of the present invention shown in FIG.

Referring to FIG. 3, the embodiment of the present invention includes a mold unit 200 including an LED light source unit therein, a lens 202 having a hole in a central portion thereof, and an encapsulant 201 filled through the hole of the lens. It is largely composed of

4 to 6 are perspective and side views of various LED packages according to an embodiment of the present invention.

Referring to FIG. 4, the basic shape of the LED light source unit is mounted in the mold unit 300 and includes a lens 302 including a hole thereon and an encapsulant 301 filled through the hole. The top of the lens has the shape of a compound aspheric surface, and the side surface of the lens may have an inclined surface to have a conical shape. The total reflection of the light occurs at the solid side of the lens, and the total efficiency of the light incident within the desired direction is increased through the total reflection.

The embodiment described in FIG. 4 may be referred to as a structure optimized to have a light extraction efficiency and a specific directivity shape. The light efficiency of a typical LED package depends on the amount of light incident into a desired direction angle through total reflection of light depending on the shape of the lens.

The specific orientation refers to a form in which the angle of inclination of the lens and the shape of the image side lens are adjusted to have a specific orientation.

In case of back light unit (BLU) use, it is designed to have a wide angle of view and in the case of a flash-like use, it is designed to have a small angle of view.

Referring to FIG. 4, the light extraction efficiency is lowered by about 5 to 10% compared to FIG. 2, but according to the lens shape of the composite aspherical surface, an arbitrary orientation angle within 5 to 100 degrees can be made.

5 is another embodiment of the present invention, referring to FIG. 5, the LED light source unit 403 is mounted on the substrate 410 without being mounted on the mold unit, and is electrically connected through the lead unit 404. The lens 402 is mounted on the top and the encapsulant 401 is filled through the hole, but the lens on the LED is directly fixed.

The LED light source part may be mounted inside the mold part, but the embodiment is configured to be mounted on the substrate without the mold part, so that the height of the entire package is lowered and the light efficiency of the lens is inhibited by the low reflectance by the mold part. It can be improved by using total reflection of the side part, so the light extraction efficiency of the whole package is relatively improved.

That is, since the reflectance of the inner side reflecting portion of the mold portion of the LED package is generally about 40 to 70%, the efficiency of light passing through this portion is very low. On the other hand, when the lens is totally reflected on the substrate as in the above embodiment without using the mold in forming the LED package, the loss is only about 5%, so the light gain can be remarkably improved.

Referring to FIG. 6, another embodiment of the present invention configures a lens 502 shape of an LED package mounted on the top of the fresnel to have directivity of light emitted while lowering the height of the package.

That is, the above embodiment is to mount the LED light source unit on the substrate 510, consisting of a layer of the encapsulant 501 and the Fresnel lens 502 thereon.

The formed Fresnel shape basically has a radius of curvature and an aspheric coefficient.

The embodiment can change the lens according to the utilization of various LED products, it is also possible to use a fly-eye lens or a lenticular lens sheet.

It can also be optimized for micro-level patterns, such as a diffractive lens (DOE).

Of course, the pattern formed does not necessarily have to be symmetrical.

For example, various types of optical lens patterns such as spherical, aspherical, compound aspherical, fresnel, diffractive lens (DOE), fly eye lens, and lenticular lens can be used in combination. The optical power of left, right and up and down can be different. By using an optical pattern in the form of a cylinder array (array) or using a Fresnel shape having only one portion of the power, the optical power can be implemented differently.

In an embodiment of the present invention according to the embodiment of FIG. 6, a vertical section is generated rather than an inclined portion of the pattern due to the Fresnel pattern, so that the light that experiences this section is totally reflected and re-reflected to the inside or double or Because of the high possibility of triple reflection, the light extraction efficiency may be reduced, but the advantage of reducing the height of the LED package to the minimum enables the use in various LED products.

In the present invention, if the lens pattern of the upper portion is configured in various ways or designed and matched as necessary, the optical effect and the design effect can be achieved simultaneously.

Typically, as in the case of the LED module for camera flash, it is possible to minimize the height and obtain the optical effect and design satisfaction at the same time.

One embodiment of the present invention proposes a method of constructing the above-mentioned various LED packages with improved light efficiency.

In particular, the present invention is characterized in that the hole is formed in the central portion of the lens and the sealing material is filled in the upper portion of the LED light source through the hole.

However, the encapsulant may be filled after the lens is mounted, or may be filled in the upper part of the LED light source before the lens is mounted, and then the encapsulant of the remaining portion is filled through the hole after the lens is fixed thereon.

The filling of the encapsulant is filled while being careful not to generate bubbles between the LED light source and the lens, so as to be filled, it is preferable that the light emitted from the LED is refracted due to the air gap so that extraction efficiency is not lowered.

The encapsulant may include a phosphor, so that the light emitted from the LED light source may change its wavelength due to various phosphors, thereby inducing various colors in addition to the color of the original light.

When the encapsulant includes a phosphor, the distribution of the phosphor may be variously adjusted. In particular, the encapsulant filled in the hole of the lens may be adjusted so that the phosphor is not included.

In the present invention, the portion in which the LED light source unit is mounted or fixed is not limited to its shape or material, and the fixing method may be fixed by various known chip attachment methods such as wire bonding or flip chip bonding.

As described above, the present invention has been described with reference to a preferred embodiment of the present invention, but those skilled in the art can 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 appreciated that modifications and variations can be made.

As described above, according to the present invention, it is possible to manufacture an LED single package that can adjust the orientation angle by improving the light efficiency of the LED through the application of various package configurations or by optimizing the surface shape of the optical lens used. have.

In addition, the present invention proposes a package consisting of an optical lens integrated with the LED while having a hole in the center, and thus almost all products have a direct angle of about 120 degrees due to the low light efficiency and the flat encapsulation layer of the conventional LED package. It has the effect of solving the problem.

In addition, using the configuration according to the present invention has the effect of increasing the light extraction efficiency by more than 20% while satisfying the convenience of the process, there is an effect that can easily implement a product capable of LED single-piece package according to the desired orientation angle.

Claims (13)

An LED light source unit; A lens positioned above the LED light source and having a hole formed around an optical axis of the LED light source; And LED package for improving light efficiency, characterized in that it comprises an encapsulant filled between the LED light source and the lens through the hole. The LED package of claim 1, wherein the LED light source unit is installed inside a mold unit or a substrate having a predetermined shape and is electrically connected through a lead unit. The LED package of claim 2, wherein the LED light source unit installed on the substrate is fixed by any one of a guide hole, an intaglio recessed portion, and an embossed recessed portion. The LED package of claim 1, wherein the hole has a diameter of 0.2 mm or more and 2/3 or less of the entire diameter of the lens. The LED package of claim 1, wherein the lens is made of a plastic material. According to claim 1, wherein the shape of the lens is any one selected from the group consisting of spherical, aspherical, compound aspherical, fresnel, diffractive lens (DOE), fly eye lens, lenticular lens LED package for improving the light efficiency, characterized in that one shape. The method of claim 1, wherein the material of the encapsulation material LED package for improving the light efficiency, characterized in that at least one selected from the group consisting of epoxy-based, silicon-based material. The LED package of claim 1 or 7, wherein the encapsulant further comprises a phosphor. The LED package of claim 1, wherein the lens further comprises one or more air bleeding passages on the lower contact boundary surface.  Installing an LED light source unit in a mold unit or a substrate having a predetermined shape and electrically connecting the LED light source unit through a lead unit; Forming a hole in the center of the lens; Mounting the lens on which the hole is formed so that the optical axis of the hole and the LED light source unit coincide with each other; And Method of manufacturing an LED package with improved light efficiency, characterized in that it comprises the step of filling the sealing material through the hole of the lens. The method of claim 10, wherein the encapsulant is filled so that no air gap is formed on a light propagation path between the LED light source and the stove. The method according to claim 10, wherein in the filling of the encapsulant, the encapsulant includes a phosphor or a phosphor at the beginning of filling but does not include a phosphor at the time of filling the hole of the lens. Improved method of manufacturing LED packages.  Installing an LED light source unit in a mold unit or a substrate having a predetermined shape and electrically connecting the LED light source unit through a lead unit; Surrounding the LED light source with an encapsulant including a phosphor; Forming a hole in the center of the lens, and fixing the lens on the encapsulant layer such that the optical axis of the hole and the LED light source unit coincide with each other and positioned above the LED light source unit; And The method of manufacturing an LED package with improved light efficiency, characterized in that it comprises the step of further filling the encapsulant through the hole of the lens.

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