LIGHT EMITTING PACKAGE STRUCTURE

A light emitting package structure includes a light emitting unit, a reflective layer, a reflective element and an optical layer. The light emitting unit has a top surface, a bottom surface and sidewall surfaces. The bottom surface and the top surface are opposing to each other. The sidewall surfaces are between the top surface and the bottom surface. The light emitting unit further has an electrode portion on the bottom surface. The reflective layer encloses the sidewall surfaces of the light emitting unit. The reflective element is disposed on the light emitting unit and the reflective layer. The optical layer includes a phosphor layer, a light diffusion layer or a combination thereof. The optical layer is disposed between the top surface of the light emitting unit and the reflective element.

BACKGROUND

Technical Field

The disclosure relates to a light emitting package structure.

Description of the Related Art

The packaging technology for a light-emitting diode (LED) is one of the key development technologies of the semiconductor industry at present. The developing trends of the lateral LED and the vertical LED which apply the wire-bonding packaging technology, and the flip-chip LED which applies the flip-chip packaging technology both are brightness improvement, volume reduction, and reliability improvement.

For the flip-chip packaging technology, a chip scale light-emitting diode packaging structure has been developed, which can achieve the purpose of miniaturization of the whole volume through appropriate structural designs. However, for the light-emitting diode package structure fabricated with the chip scale packaging technology, there are still great demands of improving the performances in terms of brightness, volume, light emitting angle, etc.

SUMMARY

The present invention relates to a light emitting package structure.

According to a concept of the present invention, a light emitting package structure is provided, which comprises a light emitting unit, a reflective layer, a reflective element and an optical layer. The light emitting unit has a top surface, a bottom surface and sidewall surfaces. The bottom surface and the top surface are opposing to each other. The sidewall surfaces are between the top surface and the bottom surface. The light emitting unit further has an electrode portion on the bottom surface. The reflective layer encloses the sidewall surfaces of the light emitting unit. The reflective element is disposed on the light emitting unit and the reflective layer. The optical layer comprises a phosphor layer, a light diffusion layer or a combination thereof. The optical layer is disposed between the top surface of the light emitting unit and the reflective element.

According to an embodiment, the electrode portion of the light emitting unit is exposed by an external surface of the light emitting package structure.

According to an embodiment, a top surface of the reflective layer is substantially level with the top surface of the light emitting unit.

According to an embodiment, the light emitting package structure further comprises a light blocking layer disposed on the reflective element.

According to an embodiment, the reflective element has one or more reflective extension portions covering a portion of a sidewall surface of the optical layer and a portion of a sidewall surface of the reflective layer.

According to an embodiment, the one or more reflective extension portions cover one surface, two surfaces or three sidewall surfaces of the optical layer.

According to an embodiment, the light blocking layer has one or more light blocking extension portions covering the one or more reflective extension portions.

According to an embodiment, a lateral size of the light blocking layer and the reflective element becomes smaller gradually along a direction from a bottom of the reflective element to a top of the light blocking layer.

According to an embodiment, the light emitting unit comprises a blue LED chip.

According to an embodiment, the light emitting package structure further comprises one or more additional light emitting units.

According to an embodiment, the one or more additional light emitting units are a red LED chip, a green LED chip or a combination thereof.

According to an embodiment, the reflective layer encloses sidewall surfaces of the one or more additional light emitting units.

According to an embodiment, a transmittance of the light diffusion layer is 99% or higher.

According to an embodiment, the reflective element and the reflective layer have a light reflectance of 95% or higher.

According to another concept of the present invention, a light emitting package structure is provided, which comprises a light emitting unit, a reflective layer, an optical layer and a light blocking layer. The light emitting unit has a top surface, a bottom surface and sidewall surfaces. The bottom surface and the top surface are opposing to each other. The sidewall surfaces are disposed between the top surface and the bottom surface. The light emitting unit further has an electrode portion on the bottom surface. The reflective layer encloses the sidewall surfaces of the light emitting unit. The optical layer comprises a phosphor layer, a light diffusion layer or a combination thereof. The optical layer is disposed on the top surface of the light emitting unit. The light blocking layer encloses a sidewall surface of the optical layer.

The above and other embodiments of the disclosure will become better understood with regard to the following detailed description of the non-limiting embodiment(s). The following description is made with reference to the accompanying drawings.

DETAILED DESCRIPTION

The illustrations may not be necessarily drawn to scale, and there may be other embodiments of the present disclosure which are not specifically illustrated. Thus, the specification and the drawings are to be regard as an illustrative sense rather than a restrictive sense. Moreover, the descriptions disclosed in the embodiments of the disclosure such as detailed construction, manufacturing steps and material selections are for illustration only, not for limiting the scope of protection of the disclosure. The steps and elements in details of the embodiments could be modified or changed according to the actual needs of the practical applications. The disclosure is not limited to the descriptions of the embodiments. The illustration uses the same/similar symbols to indicate the same/similar elements. The term “substantially level with” described herein permits an industry-accepted tolerance such as within 10%, or within 5%, or within 3%, or within 2%, or within 1%, or within 0.5%.

As shown inFIG. 1, a light emitting package structure comprises a light emitting unit110, a reflective layer220, an optical layer330and a light blocking layer440.

The light emitting unit110has a top surface111, a bottom surface112and sidewall surfaces113. The sidewall surfaces113are between the top surface111and the bottom surface112. The light emitting unit110may be a flip chip, and has electrode portions114on the bottom surface112. In an embodiment, the light emitting unit110comprises a light emitting diode (LED) chip such as a blue LED chip.

In embodiments, the light emitting package structure is a chip scale package (CSP) structure. The electrode portions114of the light emitting unit110may be exposed by an external surface of the light emitting package structure. The electrode portions114of the light emitting unit110are not covered by a substrate. The electrode portions114are an electrode pair used for providing an electrical connection to an external circuit for driving the light emitting unit110.

In embodiments, the light emitting package structure is not limited to a chip scale package structure. In another embodiment, the light emitting package structure may further comprise a substrate (not shown), and the light emitting unit110and the reflective layer220are disposed on a top surface of the substrate. The electrode portions114of the light emitting unit110may be electrically connected to an external circuit through conductive elements of the substrate so as to drive the light emitting unit110.

The reflective layer220encloses the sidewall surfaces113of the light emitting unit110. The reflective layer220may enclose all of the sidewall surfaces113of the light emitting unit110. For example, the light emitting unit110of a rectangular shape has four sidewall surfaces113, and the reflective layer220is disposed on the four sidewall surfaces113of the light emitting unit110. A top surface221of the reflective layer220and the top surface111of the light emitting unit110are substantially level with each other. The reflective layer220may be a resin mixture having a reflective particle, for example. In a preferred embodiment, the reflective layer220has a reflectance of 95% or higher to a light emitted from the light emitting unit110, and therefore can effectively reflect a lateral light from the light emitting unit110to provide a better light collecting effect.

The optical layer330may be disposed on the top surface111of the light emitting unit110and the top surface221of the reflective layer220. The optical layer330may comprise a phosphor layer, a light diffusion layer or a combination thereof. The phosphor layer can provide a wavelength converting effect to a light emitted from the light emitting unit110so as to provide a light having various colors different from a color of the light emitted from the light emitting unit110for the light emitting package structure. The light diffusion layer can provide a light equalizing effect. In an embodiment, the optical layer330is the phosphor layer. In another embodiment, the optical layer330is the phosphor layer and the light diffusion layer, wherein the phosphor layer is on the top surface111of the light emitting unit110, and the light diffusion layer is on a top surface of the phosphor layer. In embodiments, the light diffusion layer of the optical layer330may have a transmittance of 99% or higher. A material of the light diffusion layer of the optical layer330may comprise silicon dioxide, titanium dioxide, boron nitride, etc.

The light blocking layer440is disposed on the top surface221of the reflective layer220. The light blocking layer440encloses a sidewall surface333of the optical layer330. A sidewall surface443of the light blocking layer440and a sidewall surface223of the reflective layer220are substantially level with each other. A top surface441of the light blocking layer440and a top surface331of the optical layer330are substantially level with each other. The light blocking layer may be a light absorbing element having a dark color or a black color, etc. The light blocking layer may have a light transmittance of 5% or lower. A material of the light blocking layer440may be a mixture of a resin and carbon black, for example. The light blocking layer440can block an emitting light of large angle, by which a contrast ratio of the arrayed light emitting package structures can be increased.

FIG. 2illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 1with the following description. The light emitting package structure further comprises a light emitting unit120and a light emitting unit130. The light emitting unit120and the light emitting unit130may comprise light emitting diode chips. In an embodiment, the light emitting unit110is a blue LED chip, the light emitting unit120is a green LED chip, and the light emitting unit130is a red LED chip. Structures of the light emitting unit120and the light emitting unit130may be similar with the structure of the light emitting unit110. For example, the light emitting unit120and the light emitting unit130may be flip chips, and have the electrode portions114on bottom surfaces of the light emitting unit120and the light emitting unit130. In embodiments, the light emitting package structure is a chip scale package structure. The electrode portions114of the light emitting unit120and the light emitting unit130may be electrode pairs exposed by an external surface of the light emitting package structure, for providing an electrical connection to an external circuit for driving the light emitting unit120and the light emitting unit130. The reflective layer220encloses the light emitting unit110, the light emitting unit120and the light emitting unit130. The light emitting unit110, the light emitting unit120and the light emitting unit130are separated from each other by the reflective layer220. The reflective layer220has a low light transmittance (such as lower than 5%), and can block light penetrating. Therefore, the reflective layer220can prevent from light interference between the light emitting unit110, the light emitting unit120and the light emitting unit130. The light emitting units of the light emitting package structure may have other quantities or other color arrangements for the light emitting chips. The optical layer330is disposed on the light emitting unit110, the light emitting unit120, the light emitting unit130and the reflective layer220. In an embodiment, the optical layer330is the light diffusion layer. In another embodiment, the optical layer330is the phosphor layer and the light diffusion layer, wherein the phosphor layer is on the light emitting unit110, the light emitting unit120, the light emitting unit130and the reflective layer220, and the light diffusion layer is on the top surface of the phosphor layer.

FIG. 3illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 1with the following description. The light emitting package structure further comprises a reflective element550. The reflective element550may be adjoined on the reflective layer220. The reflective element550is disposed between the sidewall surface333of the optical layer330and a sidewall surface444of the light blocking layer440. Light extraction can be further increased by disposing the reflective element550, and at the same time contrast ratio can be increased by the light blocking layer440. A lateral cross-section area of the optical layer330becomes larger gradually from the bottom up. The sidewall surface333of the optical layer330may be a convex curved surface, and a sidewall surface554of the reflective element550may be a concave curved surface. By which a cup-shaped reflection effect can be generated to further increase light extraction.

In embodiments, the reflective layer220and the reflective element550are high-reflectance elements. Light reflectance of the reflective layer220and the reflective element550may be 95% or higher. A composition of the reflective layer220may be different from a composition of the reflective element550. A material of the reflective layer220may comprise nano-scale titanium compound, or silicon compound, etc. A material of the reflective element550may comprise nano-scale titanium compound or silicon compound, etc.

FIG. 4illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 3with the following description. Besides the light emitting unit110, the light emitting package structure further comprises the light emitting unit120and the light emitting unit130. The other similar concepts may be referred to the descriptions illustrated with referring toFIG. 2and not repeated herein.

FIG. 5illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 3with the following description. A lateral cross-section area of the optical layer330becomes smaller from the bottom up. The sidewall surface333of the optical layer330may be a concave curved surface, and the sidewall surface554of the reflective element550may be a convex curved surface. By which, an area of an emitting light can be reduced, and an effect as a point light source can be approached.

FIG. 6illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 5with the following description. Besides the light emitting unit110, the light emitting package structure further comprises the light emitting unit120and the light emitting unit130. The other similar concepts may be referred to the descriptions illustrated with referring toFIG. 2and not repeated herein.

As shown inFIG. 1toFIG. 2, the light blocking layer440of the light emitting package structure is disposed on the sidewall surface333of the optical layer330. As shown inFIG. 3toFIG. 6, the reflective element550and the light blocking layer440of the light emitting package structure are disposed on the sidewall surface333of the optical layer330. The reflective element550and the light blocking layer440have low light transmittances (such as lower than 5%), by which a contrast ratio can be increased. Through this arrangement, a light emitted from the light emitting unit emits away the light emitting package structure mainly from the top surface331of the optical layer330. The light emitting package structure is a top view type light emitting package structure. In embodiments, the optical layer330has a rectangular shape having four sidewall surfaces333, and the light blocking layer440, or both the light blocking layer440and the reflective element550are disposed on the four sidewall surfaces333of the optical layer330. It can prevent a light emitted by the light emitting package structure from exciting a phosphor layer of an adjacent un-driven light emitting package structure that would affect a contrast ratio.

FIG. 7illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 1with the following description. The light emitting package structure further comprises the reflective element550. The reflective element550has a film structure, and is disposed on the top surface331of the optical layer330. The optical layer330and the reflective element550have a uniform lateral size. The reflective element550is a resin mixture having a reflective particle, preferably.

FIG. 8illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 7with the following description. The light emitting package structure further comprises the light blocking layer440. The light blocking layer440is disposed on a top surface551of the reflective element550. A lateral size of the light blocking layer440is identical with lateral sizes of the optical layer330and the reflective element550. Disposing the light blocking layer440can prevent exciting a phosphor powder in the light emitting package structure by an incident light from an adjacent light source that would cause a cross talk problem.

FIG. 9illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 8with the following description. Besides the light emitting unit110, the light emitting package structure further comprises the light emitting unit120and the light emitting unit130. The other similar concepts may be referred to the descriptions illustrated with referring toFIG. 2and not repeated herein.

FIG. 10illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 8with the following description. Lateral sizes of the light blocking layer440and the reflective element550may be smaller than a lateral size of the optical layer330. A lateral size of the light blocking layer440and the reflective element550becomes smaller gradually along a direction from a bottom of the reflective element550to a top of the light blocking layer440.

FIG. 11illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 10with the following description. Besides the light emitting unit110, the light emitting package structure further comprises the light emitting unit120and the light emitting unit130. The other similar concepts may be referred to the descriptions illustrated with referring toFIG. 2and not repeated herein.

As shown inFIG. 7, the light emitting package structure has the optical layer330disposed between the top surface of the light emitting unit (for example comprising the light emitting unit110, but not limited thereto) and the bottom surface of the reflective element550. As shown inFIG. 8toFIG. 11, the light emitting package structure has the optical layer330disposed between the top surface of the light emitting unit (for example comprising the light emitting unit110, the light emitting unit120, and/or the light emitting unit130) and the bottom surfaces of the reflective element550and the light blocking layer440. Through this arrangement, a light emitted from the light emitting unit emits away the light emitting package structure mainly from the sidewall surface333of the optical layer330, achieving a batwing type light distribution, as shown inFIG. 12. The light emitting package structure can have a big light emitting angle, such as about 170 degrees. In addition, the light emitting package structure may have a center luminous intensity of 30% to 70%. In an embodiment, the optical layer330has a rectangular shape having four sidewall surfaces333, and a light emitted from the light emitting unit emits away the light emitting package structure from the four sidewall surfaces333.

In other embodiments, the reflective element550may have a reflective extension portion560. The reflective extension portion560covers a portion of the sidewall surface333of the optical layer330and a portion of the sidewall surface223of the reflective layer220. Additionally/otherwise, the light blocking layer440may have a light blocking extension portion470. The light blocking extension portion470covers a portion of the sidewall surface333of the optical layer330and a portion of the sidewall surface223of the reflective layer220. The light blocking extension portion470of the light blocking layer440may cover the reflective extension portion560of the reflective element550. A light emitted from the light emitting unit may emit away the light emitting package structure from the sidewall surface333of the optical layer330not covered by the reflective extension portion560and/or the light blocking extension portion470. Light emitting package structures shown inFIG. 13,FIG. 14andFIG. 15are illustrated as examples.

The light emitting package structure shown inFIG. 13is different from the light emitting package structure shown inFIG. 8with the following description.FIG. 13shows one reflective extension portion560A of the reflective extension portion560of the reflective element550.FIG. 13also shows one light blocking extension portion470A of the light blocking extension portion470of the light blocking layer440. The reflective extension portion560A is on one sidewall surface333(right sidewall surface) of the optical layer330. The light blocking extension portion470A is on a sidewall surface of the reflective extension portion560A. A light emitted from the light emitting unit110can emit away the light emitting package structure from the sidewall surface333(left sidewall surface) of the optical layer330not covered by the reflective extension portion560A and the light blocking extension portion470A.

The light emitting package structure shown inFIG. 14is different from the light emitting package structure shown inFIG. 13with the following description.FIG. 14shows two reflective extension portions (i.e. the reflective extension portion560A and a reflective extension portion560B) of the reflective extension portion560.FIG. 14also shows two light blocking extension portions (i.e. the light blocking extension portion470A and a light blocking extension portion470B) of the light blocking extension portion470. The reflective extension portion560A and the reflective extension portion560B are on the opposing sidewall surfaces333of the optical layer330respectively. The reflective extension portion560A and the reflective extension portion560B are on the sidewall surfaces223of the reflective layer220on the opposing sidewall surfaces of the light emitting unit (comprising the light emitting unit110, the light emitting unit120, and/or the light emitting unit130), respectively. The light blocking extension portion470A and the light blocking extension portion470B are on the sidewall surfaces of the reflective extension portion560A and the reflective extension portion560B, respectively.

FIG. 15illustrates a light emitting package structure, which is different from the light emitting package structure shown inFIG. 14with the following description. Besides the light emitting unit110, the light emitting package structure further comprises the light emitting unit120and the light emitting unit130. The other similar concepts may be referred to the descriptions illustrated with referring toFIG. 2and not repeated herein.

The present invention is not limited to the above. For example, as the reflective layer220and the optical layer330have a rectangular shape having four sidewall surfaces (outer sidewall surfaces), the reflective element550may have one reflective extension portion560covering on one sidewall surface of the reflective layer220and the optical layer330, and the light blocking layer440may have one light blocking extension portion470covering the sidewall surface of the one reflective extension portion560, through this arrangement, a light emitted from the light emitting unit (comprising the light emitting unit110, the light emitting unit120, and/or the light emitting unit130) may emit away the light emitting package structure from the other three sidewall surfaces333of the optical layer330not covered by the reflective extension portion560and the light blocking extension portion470. Otherwise, as the reflective layer220and the optical layer330have a rectangular shape having four sidewall surfaces, the reflective element550may have two reflective extension portions560respectively covering on arbitrary two sidewall surfaces of the reflective layer220and the optical layer330, and the light blocking layer440may have two light blocking extension portions470covering the sidewall surfaces of the two reflective extension portions560, through this arrangement, a light emitted from the light emitting unit may emit away the light emitting package structure from the other two sidewall surfaces333of the optical layer330not covered by the reflective extension portions560and the light blocking extension portions470. Alternatively, as the reflective layer220and the optical layer330have a rectangular shape having four sidewall surfaces, the reflective element550may have three reflective extension portions560respectively covering on arbitrary three sidewall surfaces of the reflective layer220and the optical layer330, and the light blocking layer440may have three light blocking extension portions470covering the sidewall surfaces of the three reflective extension portions560, through this arrangement, a light emitted from the light emitting unit may emit away the light emitting package structure from the other one sidewall surface333of the optical layer330not covered by the reflective extension portions560and the light blocking extension portions470, which may have a luminous condition as shown inFIG. 16. The present invention is not limited thereto. The light emitting package structure of the invention can be varied according to actual demands such as a light output configuration, an amount of light emitting surface, etc.