Patent Description:
Light emitting diode (LED) has the advantages of small size, high luminous efficiency, low energy consumption and environmental protection, and can emit visible or invisible light. LED light sources are now widely used in various vehicle lamps and electronic products. However, the same type of LEDs may have different characteristics such as in brightness and color. Indeed, even LEDs manufactured in the same batch exhibit such differences. Thus, a white balance shift may occur when a plurality of light sources each having red, green and blue LEDs are lit.

In addition, with the increase in number of the light source, an illumination system would require a more complicated layout for IC chip(s) and a large number of transmission wires, for example, a complex circuit layout design in which an IC chip is used to control a plurality of LED light sources. Thus, a resulting circuit board is difficult to be reduced in size; furthermore, any malfunction of the IC chip may also cause a light emitting area to be reduced.

Recently, LED package structures, in which an IC chip and a plurality of LED light sources are packaged together, are provided. However, once packaged, such LED package structures do not allow for characteristic parameters of the LED light sources to be calibrated. As a result, even if the LED light sources have the same color and are driven under the same condition, they may have an undesirable shift in brightness or color temperature.

<CIT> discloses an LED package including a substrate, a lid, a recess between the substrate and the lid, and an LED mounted in the recess. Test contacts are provided on the top surface of the substrate and covered by a package unit.

<CIT> discloses a substrate for an LED package including a multilayered circuit base and external electrical contacts used to establish a temporary connection to power and calibration control wires. External electrical contacts are provided on the top surface of the substrate near a package unit.

In response to the above-referenced technical inadequacies, the present invention provides an LED package structure according to independent claim <NUM>, which is capable of calibrating color balance. The dependent claims show further embodiments of claim <NUM>.

In another aspect, the present invention provides a light source module including a controller and the plurality of LED package structures as mentioned above. The LED package structures are electrically connected to the controller. In each of the plurality of LED package structures, the control unit stores calibration data, and the control unit can calibrate the driving conditions of the lighting elements according to the calibration data.

One of the advantages of the present invention is that the LED package structure, in which the lighting elements, after being packaged and before practical applications, can be tested for obtaining respective characteristic parameter values to be written into the control unit. Accordingly, the control unit can calibrate the driving condition of each of the lighting elements according to the corresponding characteristic parameter value. Therefore, the lighting elements can produce respective target lighting characteristics and the LED package structure can achieve the best color balance.

These and other aspects of the present invention will become apparent from the following description of the embodiment taken in conjunction with the following drawings and their captions, although variations and modifications therein may be affected without departing from the scope of the invention as defined by the claims.

The present invention will become more fully understood from the following detailed description and accompanying drawings.

The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Titles or subtitles can be used herein for the convenience of a reader, which shall have no influence on the scope of the present invention.

The use of examples anywhere in this specification including examples of any terms is illustrative only, and in no way limits the scope and meaning of the present invention or of any exemplified term. Likewise, the present invention is not limited to various embodiments given herein.

Referring to <FIG>, a first embodiment of the present invention provides an LED package structure <NUM> including a multilayered circuit board <NUM>, a lighting unit <NUM>, a control unit <NUM>, a reflecting unit <NUM> and a package unit <NUM>. It should be noted that, the lighting unit <NUM> and the control unit <NUM> can be integrated in a single package structure by the multilayered circuit board <NUM>. Accordingly, the lighting unit <NUM> can be tested to obtain its electrical and optical characteristics by the lamination design of the multilayered circuit board <NUM> before use, and the color balance (e.g., white balance) thereof can be calibrated by the control unit <NUM>. However, the above description is merely exemplary, and is not intended to limit the present invention.

In the present embodiment, as shown in <FIG>, the multilayered circuit board <NUM> includes an internal connecting circuit IW and a plurality of testing pads. The internal connecting circuit IW includes a plurality of electrical transferring interfaces CI. The electrical transferring interfaces CI are respectively and electrically connected to the testing pads. The lighting unit <NUM> is disposed on the multilayered circuit board <NUM> and includes a plurality of lighting elements. The lighting elements are respectively and electrically connected to the electrical transferring interfaces CI, such that an outside electrical connection can be provided to each of the lighting elements by the corresponding testing pad. The control unit <NUM> is disposed within the multilayered circuit board <NUM> and separated from the lighting unit <NUM>. The control unit <NUM> is respectively and electrically connected to the lighting elements of the lighting unit <NUM> by the electrical transferring interfaces CI. The reflecting unit <NUM> is disposed on the multilayered circuit board <NUM> and surrounds the lighting unit <NUM>. The package unit <NUM> covers the lighting unit <NUM>.

The following will respectively describe the detail features of the elements, and subsequently describe the relative positional relationship between the elements.

Reference is made to <FIG> together with <FIG>. The multilayered circuit board <NUM> can be made by a general manufacturing process. The multilayered circuit board <NUM> serves as the foundation of the entire package structure for disposing the lighting unit <NUM>, the control unit <NUM>, the reflecting unit <NUM> and the package unit <NUM>. The multilayered circuit board <NUM> includes a base layer <NUM>, a first circuit layer <NUM>, an insulating layer <NUM>, a second circuit layer <NUM> and a third circuit layer <NUM>. The first circuit layer <NUM> is formed on a surface (e.g., a top surface) of the base layer <NUM>. The insulating layer <NUM> is formed on the first circuit layer <NUM>. The second circuit layer <NUM> is formed on the first circuit layer <NUM>. The third circuit layer <NUM> is formed on another surface (e.g., a bottom surface) of the base layer <NUM>. In the present embodiment, the base layer <NUM> and the insulating layer <NUM> may be formed from polymeric materials, and the first, second, and third circuit layers <NUM>, <NUM>, <NUM> may be formed from high conductivity metals or alloys, but the present invention is not limited thereto.

More specifically, the first circuit layer <NUM> and the second circuit layer <NUM> jointly form the internal connecting circuit IW. The second circuit layer <NUM> includes a common electrode <NUM> and a plurality of individual extracting electrodes <NUM>. The common electrode <NUM> may be strip-shaped and the extracting electrodes <NUM> may each be L-shaped. The third circuit layer <NUM> includes a plurality of individual testing pads that are exemplified by a first testing pad <NUM>, a second testing pad <NUM> and a third testing pad <NUM> in the present embodiment. In addition, the third circuit layer <NUM> further includes a plurality of individual electrical connecting pads that are exemplified by a first electrical connecting pad <NUM> and a plurality of second electrical connecting pads <NUM> in the present embodiment. In use, the control unit <NUM> can be buried within the base layer <NUM> to control the lighting unit <NUM>. The second circuit layer <NUM> can serve as the driving and controlling circuit of the lighting unit <NUM>. The first circuit layer <NUM> is configured to provide a downward and outward electrical connection path.

The first circuit layer <NUM> has a plurality of first transferring points P1, the insulating layer <NUM> has a plurality of first conductive vias <NUM>, and the second circuit layer <NUM> has a plurality of second transferring points P2. The first transferring points P1 correspond in position to the first conductive vias <NUM> and the second transferring points P2. The first transferring points P1 are electrically connected to the second transferring points P2 by the first conductive vias <NUM> to form the plurality of electrical transferring interfaces CI. In the present embodiment, each of the first conductive vias <NUM> includes a first through hole <NUM> passing through the insulating layer <NUM> and a conductive pillar <NUM> disposed in the first through hole <NUM>. The conductive pillar <NUM> maybe formed from high conductivity metals or alloys, but is not limited thereto.

The base layer <NUM> has a plurality of second conductive vias <NUM> that are electrically connected to the first circuit layer <NUM> and the testing pads. More specifically, the second conductive vias <NUM> correspond in position to the first, second, and third testing pads <NUM>, <NUM>, <NUM> of the third circuit layer <NUM>. The first, second, and third testing pads <NUM>, <NUM>, <NUM> are electrically connected to the first transferring points P1 of the first circuit layer <NUM>.

In the present embodiment, the base layer <NUM> can include an upper base section 11a and a lower base section 11b that are laminated together. The material of the upper base section 11a may be the same as or different from that of the lower base section 11b. The control unit <NUM> can be buried within the upper base section 11a without overlapping the second conductive vias <NUM>, and is electrically connected to the first circuit layer <NUM>. More specifically, the control unit <NUM> can be a driving IC. The upper base section 11a can have an open slot <NUM> for accommodating the control unit <NUM>, and a gap-filling colloid can be filled in a remaining space of the open slot <NUM>. In certain embodiments, the control unit <NUM> is suspended in the open slot <NUM> without contacting the third circuit layer <NUM>. Furthermore, the second conductive vias <NUM> pass through the upper base section 11a and the lower base section 11b. Each of the second conductive vias <NUM> can include a second through hole <NUM>, a hole wall metal layer <NUM> disposed on a hole wall of the second through hole <NUM>, and an insulating resin material <NUM> filled in the space surroundingly defined by the hole wall metal layer <NUM>. The hole wall metal layer <NUM> maybe formed from high conductivity metals or alloys, but is not limited thereto. According to practical requirements, the second through hole <NUM> can be completely filled with a suitable metal or alloy.

In the present invention, the lighting unit <NUM> can include a plurality of lighting elements. In the present embodiment, the lighting elements are exemplified by a first lighting element <NUM>, a second lighting element <NUM> and a third lighting element <NUM> which are disposed on the second circuit layer <NUM> and parallel to each other at intervals. In certain embodiments, the first lighting element <NUM>, the second lighting element <NUM> and the third lighting element <NUM> respectively emit red light, green light and blue light. Furthermore, the first, second, and third testing pads <NUM>, <NUM>, <NUM> can be respectively and electrically connected to the first, second, and third lighting elements <NUM>, <NUM>, <NUM> by the electrical transferring interfaces CI. More specifically, the multilayered circuit board <NUM> includes a plurality of test paths, each of which is in electrical connection with the corresponding lighting element and the corresponding testing pad. For example, the first testing pad <NUM> can be electrically connected to the first lighting element <NUM> by one of the electrical transferring interfaces CI. The second testing pad <NUM> can be electrically connected to the second lighting element <NUM> by another one of the electrical transferring interfaces CI. The third testing pad <NUM> can be electrically connected to the third lighting element <NUM> by still another one of the electrical transferring interfaces CI. It should be noted that, the number and type of the lighting element can be changed to achieve a desired illumination effect.

In the present invention, each of the lighting elements has a first electrode contact and a second electrode contact. For example, in the present embodiment, the first lighting element <NUM>, the second lighting element <NUM> and the third lighting element <NUM> are each a flip chip LED. The first lighting element <NUM> includes a first electrode contact <NUM> and a second electrode contact <NUM> which are substantially coplanar with each other. The second lighting element <NUM> includes a first electrode contact <NUM> and a second electrode contact <NUM> which are substantially coplanar with each other. The third lighting element <NUM> includes a first electrode contact <NUM> and a second electrode contact <NUM> which are substantially coplanar with each other. The first electrode contacts <NUM>, <NUM>, <NUM> have the same polarity, and all are bonded to the common electrode <NUM>. The second electrode contacts <NUM>, <NUM>, <NUM> have the same polarity, and are bonded to the extracting electrodes <NUM>, respectively. Accordingly, the first electrode contacts <NUM>, <NUM>, <NUM> can be electrically connected to the first electrical connecting pad <NUM> by the common electrode <NUM>. The second electrode contacts <NUM>, <NUM>, <NUM> can each be electrically connected to the control unit <NUM> by the corresponding extracting electrode <NUM> in a working stage. Furthermore, the second electrode contacts <NUM>, <NUM>, <NUM> can each be electrically connected to the first, second, or third testing pad <NUM>, <NUM>, <NUM> by the corresponding extracting electrode <NUM> in a testing stage.

In the present invention, each of the lighting elements can have a wavelength converting material thereon. In the circumstance that the first lighting element <NUM> emits red light, the first lighting element <NUM> can be a red LED chip or can include a blue LED chip and a wavelength converting layer formed on the blue LED chip. The wavelength converting layer may have a red phosphor. In the circumstance that the second lighting element <NUM> emits green light, the second lighting element <NUM> can be a green LED chip or can include a blue LED chip and a wavelength converting layer formed on the blue LED chip. The wavelength converting layer may have a green phosphor. In the circumstance that the third lighting element <NUM> emits blue light, the third lighting element <NUM> can be a blue LED chip. However, the above description is merely exemplary, and is not intended to limit the present invention. According to practical requirements, the colors and implementation manners of the lighting elements can be changed by persons skilled in the art.

In the LED package structure S of the present invention, the lighting elements can be tested for obtaining respective characteristic parameter values after being packaged and before use. As shown in <FIG>, the first, second, and third lighting elements <NUM>, <NUM>, <NUM> can be respectively tested by the test paths to obtain their electrical and optical characteristics such as voltages, wavelengths and brightness. The test paths are provided at least by the first circuit layer <NUM>, the second circuit layer <NUM>, the third circuit layer <NUM> and electrical conducting structures <NUM>. The characteristic parameter value of each of the lighting elements can be written into the control unit <NUM>.

In practice, as shown in <FIG>, electrical signals can be transmitted to the control unit <NUM> by the operation paths, such that the control unit <NUM> can control the first, second, and third lighting elements <NUM>, <NUM>, <NUM> according to such electrical signals. The operation paths are provided at least by the first circuit layer <NUM>, the second circuit layer <NUM>, the electrical conducting structures <NUM> and the control unit <NUM>. In the present invention, different driving signals can be respectively transmitted to the first, second, and third lighting elements <NUM>, <NUM>, <NUM> by the extracting electrodes <NUM>, such that the driving condition such as a driving current value of each of the first, second, and third lighting elements <NUM>, <NUM>, <NUM> can be independently controlled.

More specifically, in practice, the first, second, and third testing pads <NUM>, <NUM>, <NUM> in the LED package structure S do not serve any purpose. The first, second, and third testing pads <NUM>, <NUM>, <NUM> merely serve as testing points for testing the first, second, and third lighting elements <NUM>, <NUM>, <NUM> in the manufacturing process. The test results regarding the electrical and optical characteristics of the first, second, and third lighting elements <NUM>, <NUM>, <NUM> can be compared with desired results, so as to calculate the calibration data of the first, second, and third lighting elements <NUM>, <NUM>, <NUM> which can be inputted into the control unit <NUM>. Accordingly, the control unit <NUM> can adjust the driving conditions of the first, second, and third lighting elements <NUM>, <NUM>, <NUM> according to the calibration data. Therefore, different colored lights emitted from the first, second, and third lighting elements <NUM>, <NUM>, <NUM> can uniformly mix together to produce a colored or white light of a desired characteristic (e.g., a warm white or cold white light).

If necessary, the multilayered circuit board <NUM> can further include a first solder mask layer <NUM> and a second solder mask layer <NUM>. The first solder mask layer <NUM> can be formed on the second circuit layer <NUM> and a portion of the second circuit layer <NUM> can be exposed from the first solder mask layer <NUM>. The second solder mask layer <NUM> can be formed on another surface of the base layer <NUM> without overlapping the third circuit layer <NUM>. The second solder mask layer <NUM> is substantially coplanar with the third circuit layer <NUM>. A portion of the third circuit layer <NUM> including the first, second, and third testing pads <NUM>, <NUM>, <NUM> can be exposed from the second solder mask layer <NUM>. In the present embodiment, the areas of the first solder mask layer <NUM> corresponding in position to the first, second, and third lighting elements <NUM>, <NUM>, <NUM> can be hollowed out, so as to allow the first electrode contacts <NUM>, <NUM>, <NUM> to be connected to the common electrode <NUM> and allow the second electrode contacts <NUM>, <NUM>, <NUM> to be respectively connected to the extracting electrodes <NUM>.

Reference is made to <FIG> together with <FIG>. The outer periphery of the multilayered circuit board <NUM> can be formed with a plurality of electrical conducting structures <NUM> serving as signal transmitting interfaces or connecting interfaces for external devices. More specifically, the electrical conducting structures <NUM> are not only in electrical connection with the first, second, and third testing pads <NUM>, <NUM>, <NUM>, but also in electrical connection with the lighting unit <NUM> and the control unit <NUM>. The first circuit layer <NUM>, the second circuit layer <NUM>, the first conductive vias <NUM> and the second conductive vias <NUM> can jointly form a plurality of electrical connection paths such as test and operation paths. In the present embodiment, the electrical conducting structures <NUM> are arranged in pairs opposite to one another and pass through the base layer <NUM>, the first circuit layer <NUM> and the second circuit layer <NUM>. Each of the electrical conducting structures <NUM> is a conductive half hole located on an outer peripheral wall of the multilayered circuit board <NUM>, but is not limited thereto. Also, each of the electrical conducting structures <NUM> can be a conductive via passing through the multilayered circuit board <NUM>.

The reflecting unit <NUM> can be disposed on the multilayered circuit board <NUM>. In the present embodiment, the reflecting unit <NUM> is disposed upon the first solder mask layer <NUM>. Furthermore, the reflecting unit <NUM> surrounds the first, second, and third lighting elements <NUM>, <NUM>, <NUM>. More specifically, the reflecting unit <NUM> can be in the form of a closed frame and has an inner peripheral surface <NUM> facing the lighting unit <NUM> and a top surface <NUM> connected to the inner peripheral surface <NUM>. In order to increase light emitting efficiency and reliability, the inner peripheral surface <NUM> of the reflecting unit <NUM> can have a metal reflecting layer <NUM> covered thereon. If necessary, the metal reflecting layer <NUM> can extend onto a portion of the top surface <NUM>. In the present embodiment, the reflecting unit <NUM> may be formed from a white reflective material, and the metal reflecting layer <NUM> may be formed from an aluminum alloy, silver alloy or gold silver alloy. However, the above description is merely exemplary, and is not intended to limit the present invention. It should be noted that, in the presence of the metal reflecting layer <NUM>, the material of the reflecting unit <NUM> has a reduced water absorption rate, thereby increasing the reliability of the LED package structure S.

The package unit <NUM> covers the first lighting element <NUM>, the second lighting element <NUM> and the third lighting element <NUM> of the lighting unit <NUM> and may be a light-permeable colloid. In the present embodiment, the package unit <NUM> may be formed from light-permeable materials such as epoxy and silicone. In other embodiments (not shown), the package unit <NUM> may be a light-permeable cover such as a glass cover, or may include a light-permeable cover and a light-permeable colloid. However, the above description is merely exemplary, and is not intended to limit the present invention.

In order to make the purpose, technical solution and advantages of the present invention clearer, the following will further describe the electrical connection relationship between the multilayered circuit board <NUM>, the lighting unit <NUM> and the control unit <NUM>.

As shown in <FIG>, the control unit <NUM> has an upper surface provided with a plurality of electrical contacts <NUM>. In use, three of the electrical contacts <NUM> (e.g., three electrical contacts <NUM> located on the upper right half section of the upper surface) can be respectively and electrically connected to the first, second, and third lighting elements <NUM>, <NUM>, <NUM>. More specifically, said three electrical contacts <NUM> can be respectively and electrically connected to the corresponding three of the first transferring points P1 of the first circuit layer <NUM>. Accordingly, said three electrical contacts <NUM> can be respectively and electrically connected to the second electrode contacts <NUM>, <NUM>, <NUM> of the first, second, and third lighting elements <NUM>, <NUM>, <NUM> by the corresponding three of the electrical transferring interfaces CI.

Furthermore, a number of the electrical contacts <NUM> (e.g., four electrical contacts <NUM> located on the left half section of the upper surface) can be respectively and electrically connected to the number of the electrical conducting structures <NUM>. More specifically, said electrical contacts <NUM> can be respectively and electrically connected to the corresponding first transferring points P1 of the first circuit layer <NUM>. Accordingly, said electrical contacts <NUM> can be respectively and electrically connected to the electrical conducting structures <NUM> located on an outer peripheral wall of the multilayered circuit board <NUM> by the corresponding electrical transferring interfaces CI. In the present embodiment, such electrical conducting structures <NUM> can respectively serve as a programming signal input terminal (also called "PROG terminal"), a data signal input terminal (also called "DAI" terminal), a clock signal input terminal (also called "CKI" terminal) and a power supply terminal (also called "LED VDD" terminal) of the light emitting unit <NUM>, but are not limited thereto.

In addition, another number of the electrical contacts <NUM> (e.g., three electrical contacts <NUM> located on the lower right half section of the upper surface) can be respectively and electrically connected to another number of the electrical conducting structures <NUM>. More specifically, said electrical contacts <NUM> can be respectively and electrically connected to the corresponding first transferring points P1 of the first circuit layer <NUM>. Accordingly, said electrical contacts <NUM> can be respectively and electrically connected to the electrical conducting structures <NUM> located on another opposite outer peripheral wall of the multilayered circuit board <NUM> by the corresponding electrical transferring interfaces CI. In the present embodiment, such electrical conducting structures <NUM> can respectively serve as a data signal output terminal (also called "DAO" terminal), a ground terminal (also called "GND" terminal), a clock signal output terminal (also called "CKO" terminal) and another power supply terminal (also called "VDD" terminal), but are not limited thereto.

Reference is now made to <FIG> and <FIG>. As mentioned above, the LED package structure S of the present invention, before practical applications, can be tested for obtaining respective original lighting characteristics (e.g., original brightness) of the first, second, and third lighting elements <NUM>, <NUM>, <NUM> by a testing device <NUM> and via the test paths that are at least formed by the first, second, and third testing pads <NUM>, <NUM>, <NUM>. The testing device <NUM> can generate calibration data according to a proportional relationship between the original lighting characteristics and target lighting characteristics (e.g., target brightness), and the calibration data can be written into the control unit <NUM> by the electrical conducting structure <NUM> serving as the PROG terminal. In practice, the control unit <NUM> can respectively calibrate the driving conditions of the first, second, and third lighting elements <NUM>, <NUM>, <NUM> according to the calibration data, so as to allow the first, second, and third lighting elements <NUM>, <NUM>, <NUM> to respectively produce the target lighting characteristics. Therefore, the color calibration of the LED package structure S of the present invention can be completed.

Referring to <FIG>, a second embodiment of the present invention provides an LED package structure S that uses wire bonding technology. The LED package structure S includes a multilayered circuit board <NUM>, a lighting unit <NUM>, a control unit <NUM>, a reflecting unit <NUM> and a package unit <NUM>.

The multilayered circuit board <NUM> includes an internal connecting circuit IW and a plurality of testing pads (i.e., a first testing pad <NUM>, a second testing pad <NUM> and a third testing pad <NUM>). The internal connecting circuit IW includes a plurality of electrical transferring interfaces CI that are respectively and electrically connected to the testing pads. The lighting unit <NUM> is disposed on the multilayered circuit board <NUM> and includes a plurality of lighting elements (i.e., a first lighting element <NUM>, a second lighting element <NUM> and a third lighting element <NUM>). The lighting elements are respectively and electrically connected to the electrical transferring interfaces CI, such that an outside electrical connection can be provided to each of the lighting elements by the corresponding testing pad. The control unit <NUM> is disposed on the multilayered circuit board <NUM> and is separated from the lighting unit <NUM>. Furthermore, the control unit <NUM> is electrically connected to the first, second, and third lighting elements <NUM>, <NUM>, <NUM> of the lighting unit <NUM> by the electrical transferring interfaces CI. The reflecting unit <NUM> is disposed on the multilayered circuit board <NUM> and surrounds the lighting unit <NUM>. The package unit <NUM> covers the lighting unit <NUM>. The technical details of the multilayered circuit board <NUM>, the lighting unit <NUM>, the control unit <NUM>, the reflecting unit <NUM> and the package unit <NUM> can be referred to in the description of the first embodiment, and will not be reiterated herein.

The main differences between the present embodiment and the first embodiment are the structure of the multilayered circuit board <NUM> and the relative positional relationship between the multilayered circuit board <NUM>, the lighting unit <NUM> and the control unit <NUM>. In the present embodiment, both the lighting unit <NUM> and the control unit <NUM> are disposed upon the multilayered circuit board <NUM>. The control unit <NUM> is surrounded by the reflecting unit <NUM> and covered by the package unit <NUM>. More specifically, as shown in <FIG> and <FIG>, the second circuit layer <NUM> of the multilayered circuit board <NUM> mainly includes a common electrode <NUM> and a plurality of extracting electrodes <NUM>, and if necessary, further includes a chip mounting pad <NUM> and a plurality of transferring pads <NUM>. The common electrode <NUM> is separated from the chip mounting pad <NUM> by a distance. The extracting electrodes <NUM> and the transferring pads <NUM> are surroundingly disposed around the chip mounting pad <NUM>. Also, the common electrode <NUM> corresponds in position to the extracting electrodes <NUM>. In the present invention, a number of the extracting electrodes <NUM> are arranged between the chip mounting pad <NUM> and the common electrode <NUM>. Therefore, wires W used between the lighting unit <NUM> and the control unit <NUM> can be reduced in length, thereby reducing the risk of the wires W breaking.

In use, the lighting elements of the lighting unit <NUM> such as the first lighting element <NUM>, the second lighting element <NUM> and the third lighting element <NUM> can be entirely disposed on the common electrode <NUM>. The control unit <NUM> can be disposed on the chip mounting pad <NUM>, and be respectively and electrically connected to the first lighting element <NUM>, the second lighting element <NUM> and the third lighting element <NUM> by the extracting electrodes <NUM>. The transferring pads <NUM> are configured to form electrical connection paths between a plurality of electrical conducting structures <NUM> of the multilayered circuit board <NUM> and the control unit <NUM>.

In the present embodiment, the first lighting element <NUM> is a vertical type red LED chip, in which a first and second electrode contacts <NUM>, <NUM> are not coplanar with each other. The first electrode contact <NUM> is located at the bottom surface of the red LED chip and is connected to the common electrode <NUM>. The second electrode contact <NUM> is located at the top surface of the red LED chip and is electrically connected to one of the extracting electrodes <NUM> by a wire W. The second lighting element <NUM> is a horizontal type green LED chip, in which first and second electrode contacts <NUM>, <NUM> are located at the top surface of the green LED chip. The first electrode contact <NUM> is electrically connected to the common electrode <NUM> by a wire W, and the second electrode contact <NUM> is electrically connected to another one of the extracting electrodes <NUM> by a wire W. The third lighting element <NUM> is a horizontal type blue LED chip, in which a first and second electrode contacts <NUM>, <NUM> are located at the top surface of the blue LED chip. The first electrode contact <NUM> is electrically connected to the common electrode <NUM> by a wire W, and the second electrode contact <NUM> is electrically connected to the remaining one of the extracting electrodes <NUM> by a wire W. However, the above description is merely exemplary, and is not intended to limit the present invention.

Before use, as shown in <FIG>, the first, second, and third lighting elements <NUM>, <NUM>, <NUM> can be respectively tested by the test paths to obtain their electrical and optical characteristics such as voltages, wavelengths and brightness. The test paths are provided at least by the first circuit layer <NUM>, the second circuit layer <NUM>, the third circuit layer <NUM> and the electrical conducting structures <NUM>. In use, as shown in <FIG>, electrical signals can be transmitted to the first, second, and third lighting elements <NUM>, <NUM>, <NUM> by the operation paths. The operation paths are provided at least by the first circuit layer <NUM>, the second circuit layer <NUM>, the electrical conducting structures <NUM> and the control unit <NUM>.

More specifically, as shown in <FIG>, each of the extracting electrodes <NUM> has a first wiring area R1 and a second transferring point P2 near the first wiring area R1. The second electrode contacts <NUM>, <NUM>, <NUM> of the first, second, and third lighting elements <NUM>, <NUM>, <NUM> are respectively and electrically connected to the first wiring areas R1 of the extracting electrodes <NUM> by wires R. Also, three of the electrical contacts <NUM> of the control unit <NUM> (e.g., three electrical contacts <NUM> located on the upper right half section of the upper surface) are respectively and electrically connected to the first wiring areas R1 of the extracting electrodes <NUM> by the wires R. In addition, each of the transferring pads <NUM> has a second wiring area R2 and a second transferring point P2 near the second wiring area R2. The remaining electrical contacts <NUM> of the control unit <NUM> (e.g., two electrical contacts <NUM> located on the lower right half section of the upper surface and five electrical contacts <NUM> located on the left half section of the upper surface) can be respectively and electrically connected to the second wiring area R2 of the transferring pads <NUM> by the wires R and further electrically connected to the electrical conducting structures <NUM> and a plurality of second electrical connecting pads <NUM>.

In the present embodiment, as shown in <FIG>, a first solder mask layer <NUM> can be formed on an insulating layer <NUM> without overlapping the second circuit layer <NUM>. The first solder mask layer <NUM> is coplanar with the second circuit layer <NUM>. Accordingly, the common electrode <NUM>, the extracting electrodes <NUM>, the chip mounting pad <NUM> and the transferring pads <NUM> can be exposed from the first solder mask layer <NUM>.

Referring to <FIG>, which is to be read in conjunction with <FIG> and <FIG>, the present invention further provides a light source module Z that includes a controller C and a plurality of LED package structures S as mentioned above. The controller C is electrically connected to the LED package structures S, and generates a series of signals to control the LED package structures S. More specifically, each of the LED package structures S has a first electrical connecting pad <NUM>, which is jointly connected to a power supply end, and a plurality of second electrical connecting pads <NUM>, one of which is at a specific location and is jointly grounded. Furthermore, one of the second electrical connecting pads <NUM> of the frontmost LED package structure S which serves as a signal input end can be electrically connected to the control unit <NUM>. The adjacent two of the LED package structures S can be electrically connected to each other by respective electrical conducting structures <NUM> each serving as a signal output end.

When the light source module Z of the present invention is in use, the controller C can sequentially transmit data signals and clock signals to the LED package structures S. It should be noted that, in each of the LED package structures S, a lighting unit <NUM> can be tested for obtaining calibration data such as proportional factors relative to driving currents of first, second, and third lighting elements <NUM>, <NUM>, <NUM> and the calibration data can be written into a control unit <NUM> before practical applications. Accordingly, in each of the LED package structures S, the control unit <NUM> can respectively adjust the driving conditions of the first, second, and third lighting elements <NUM>, <NUM>, <NUM> according to the calibration data, so as to allow the first, second, and third lighting elements <NUM>, <NUM>, <NUM> to respectively produce desired colors and brightness. Therefore, the light source module Z can achieve the best color balance.

More specifically, the LED package structure S of the present invention having the above-mentioned structure is capable of performing a feedback control on the driving condition of each of the lighting elements according to its lighting characteristic. In the circumstance that the plurality of LED package structures S are used together, although the lighting elements thereof have different characteristic parameter values, they still can produce the same target lighting characteristic based on a feedback control. As shown in <FIG>, the chromaticity coordinates of the plurality of different LED package structures S all fall within a tolerance range A. In contrast, as shown in <FIG>, a plurality of LED package structures that use the same optical design but do not include any test pad cannot be tested for characteristic parameters of their lighting elements. As a result, most of the chromaticity coordinates of such LED package structures do not fall within the tolerance range A, and thus such LED package structures cannot meet the requirements of color balance required for specific applications.

Referring to <FIG>, the present invention further provides a method for manufacturing a multilayered circuit board <NUM>, which includes the following steps. Firstly, a base layer <NUM> is processed to have an open slot <NUM>. The open slot <NUM> may be formed by laser processing, but is not limited thereto. Next, the processed base layer <NUM> is attached to a temporary carrier T such as a polyimide film and a control unit <NUM> is disposed within the open slot <NUM> by the temporary carrier T. Next, a gap-filling colloid <NUM> is filled in a remaining space of the open slot <NUM> to fix the control unit <NUM> in position, and a first metal clad substrate L1 is attached to one side of the processed base layer <NUM>. The first metal clad substrate L1 includes a first resin layer L11 and a first metal layer L12 such as a copper layer formed on the first resin layer L11. Next, the temporary carrier T is removed, and a second metal clad substrate L2 is attached to the other side of the processed base layer <NUM>. The second metal clad substrate L2 includes a second resin layer L21 and a second metal layer L22 such as a copper layer formed on the first resin layer L11. Next, the first metal layer L12 is removed and a plurality of through holes L211 passing through the first resin layer L11 are formed. Finally, each of the through holes L211 is filled with an electrical conducting material M such as a copper pillar, and a circuit layer (not numbered) is formed on the first resin layer L11. If necessary, the second metal layer L22 can be formed into another circuit layer.

One of the advantages of the present invention is that by the technical features of "the lighting is disposed on the multilayered circuit board and includes a plurality of lighting elements that are respectively and electrically connected to the electrical transferring interfaces of the multilayered circuit board, such that an outside electrical connection can be provided to each of the lighting elements by the corresponding testing pad of the multilayered circuit board," and "the control unit is electrically connected to the lighting elements by the electrical transferring interfaces", the LED package structure can be tested for obtaining original lighting characteristics of the lighting elements to accordingly produce calibration data that are written into the control unit before application. Accordingly, the control unit can calibrate the driving condition of each of the lighting elements according to the calibration data, and therefore, the lighting elements can produce respective target lighting characteristics. Furthermore, the light source module using the LED package structure of the present invention can achieve the best color balance.

The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed.

Claim 1:
An LED package structure (S), comprising:
a multilayered circuit board (<NUM>) including a base layer (<NUM>), a plurality of testing pads (<NUM>, <NUM>, <NUM>), a first electrical connecting pad (<NUM>), a plurality of second electrical connecting pads (<NUM>) and a solder mask layer (<NUM>) disposed on a bottom surface of the base layer (<NUM>),
a plurality of lighting elements (<NUM>, <NUM>, <NUM>) disposed on a top surface of the base layer (<NUM>);
a control unit (<NUM>) embedded in the base layer (<NUM>) and electrically connected to the lighting elements (<NUM>, <NUM>, <NUM>);
a reflecting unit (<NUM>) disposed on a top surface of the multilayered circuit board (<NUM>) and surrounding the lighting elements (<NUM>, <NUM>, <NUM>);
a package unit (<NUM>) covering the lighting elements (<NUM>, <NUM>, <NUM>);
a plurality of test paths each in electrical connection with the first electrical connecting pad (<NUM>), one of the lighting elements (<NUM>, <NUM>, <NUM>) and one of the testing pads (<NUM>, <NUM>, <NUM>); and
a plurality of operation paths each in electrical connection with the first electrical connecting pad (<NUM>), the control unit (<NUM>), one of the lighting elements (<NUM>, <NUM>, <NUM>) and one of the second electrical connecting pads (<NUM>),
wherein a portion of the testing pads (<NUM>, <NUM>, <NUM>) is exposed from the solder mask layer (<NUM>) to provide an outside electrical connection to each of the lighting elements (<NUM>, <NUM>, <NUM>) by the corresponding testing pad (<NUM>, <NUM>, <NUM>), such that the LED package structure (S) is configured to be tested for obtaining respective characteristic parameter values of the lighting elements (<NUM>, <NUM>, <NUM>) after being packaged; and
wherein the control unit (<NUM>) is configured to record the characteristic parameter values of each of the lighting elements (<NUM>, <NUM>, <NUM>) and to calibrate the driving condition of each of the lighting elements (<NUM>, <NUM>, <NUM>) accordingly.