WO2006083110A1

WO2006083110A1 - Side view type led package

Info

Publication number: WO2006083110A1
Application number: PCT/KR2006/000356
Authority: WO
Inventors: Chan Ik Park
Original assignee: LUXPIA CO
Current assignee: LUXPIA CO
Priority date: 2005-02-02
Filing date: 2006-02-01
Publication date: 2006-08-10
Anticipated expiration: 2007-08-02
Also published as: KR100659173B1; KR20060088942A

Abstract

The present invention relates to a side-view type LED plastic package which is thin and has the enhanced heat-sinking ability. The side-view-type LED package includes an LED chip, a lead frame for mounting the LED chip thereon, and a plastic body for enclosing the lead frame and the LED chip, wherein the plastic body has a front plane (51a) having a cavity serving as a light-emitting window for exposing bonding portions (53) and (52) of the lead frame there through, a rear plane (51b) for exposing a bottom surface of the lead frame, three side planes (51c) and (5Id) sloped and defined by a mold, and a flat plane (5Ie) defined by a saw-cutting method, which would be in contact with a board-mounting surface, in which the lead frame includes a lead (56) serving as an electrical terminal, which extends from a wire bonding pad (52) in the cavity, and comes into contact with the rear plane (51b) and the flat plane (5Ie) of the plastic body, and a multi-function lead (57) serving as an electrical terminal and a heat-sink pad, which extends from a chip bonding pad (53) on which the LED chip is mounted and protrudes from both sides of the plastic body.

Description

SIDE-VIEW-TYPE LED PACKAGE

Technical Field

[1] The present invention relates to a side-view-type plastic package for a light-emitting diode (LED), and more particularly to a side-view-type plastic LED package in which a plastic body with a cavity for light reflection and collection is pre-molded before an LED chip is mounted onto a lead frame, a board mounting surface of the package is formed by a saw-cutting method for realizing a thin package and precise mounting, a chip-bonding pad extends outside the plastic body in which an extension of the chip- bonding pad protrudes from a side of the plastic body and is in contact with the board- mounting surface to enhance heat-sinking, and a bottom of the lead frame is exposed on a rear surface of the plastic body to easily dissipate heat, so that the Eutetic chip- bonding method is easily applied. In order to realize these, the package has a lead frame arrangement in which a red-light LED chip, a green-light LED chip, and a blue- light LED chip can be mounted thereon, and has a lead frame which is thicker than general lead frames. Background Art

[2] As shown in FIG. 1 and FIG. 2, there are two types of general side-view-type LED packages: One encloses only one LED chip therein as shown in FIG. 1, and the other encloses three red/green/blue primary light LED chips therein, as shown in FIG. 2.

[3] The side-view-type LED package shown in FIG. 1 has a plastic body having a cavity 11 for collecting and reflecting light, the cavity 11 being formed to avoid a wire bonding portion and a LED chip-mounted portion of a lead frame. The plastic body 10 has a cavity 11 serving as a light-emitting window and has an appearance which is defined by a mold. The plastic body 10 has a front plane through which the bonding portion of the lead frame is exposed, a rear plane having a trace of a gate through which plastic is injected into a mold, and four side planes which are slightly sloped so that a package can be easily separated from a mold after a plastic molding process, in which all six planes are defined by a mold.

[4] Leads 12 serving as electrical terminals extend out of the plastic body 10 and are exposed at the left and right sides of the plastic body 10. The leads 12 are trimmed and bent, so that end portions thereof are in contact with lower portions of both sides (board-mounting surfaces) of the plastic body 10. Considering trimming and forming processes, the leads 12 are formed as thin as possible.

[5] By the way, the forming process of the leads 12, which is a process to bend the leads 12, causes a variety of problems. First, the plastic body 10, formed to be thin to realize a thin package, comes to have a crevice or to be deformed by mechanical force exerted on the leads during the bending process. Second, due to the bent leads 12, the total thickness of the package becomes larger. Third, differences in the total thickness of the packages and horizontality of the packages depend on reproducibility of the bending process.

[6] The side-view-type LED package serves as a light source of a back-light of a small-size liquid crystal display unit. In this instance, the LED package emits light to a light guide plate disposed below a liquid crystal panel, and the light is diffused onto and reflected from the liquid guide plate, thereby lighting up the liquid crystal panel.

[7] The light emitting plate must dissipate light from the LED, which is a point light source, uniform in a perpendicular direction, so that a dark space or a luminescent line is not formed in the liquid crystal panel. Accordingly, the light guide plate has a special light diffusion and reflection pattern at a light-incident portion being in contact with the LED package so as to accommodate the light orientation characteristic of the LED package. Due to this reason, the LED package should be mounted with a predetermined angle at a predetermined position without inclination or deviation. Accordingly, the reproducibility of the lead bending process is very important.

[8] Further, since the plastic body 10 has a rough rear surface including a trace of a gate through which plastic resin is introduced into a mold not to expose a lead frame, it is difficult to transfer a process temperature. Accordingly, in the case of using the plastic body 10, there is difficulty in application of the Eutetic die-bonding process, in which the LED chip is bonded to a bonding portion of a lead frame.

[9] The Eutetic die-bonding is a die-bonding process to bond a LED chip onto a lead frame by melting a metal deposited on a rear surface of the LED chip, and can more highly reduce heat resistance with respect to a conductive epoxy adhesive bonding, thereby being in useful for stabilizing performance of LED devices emitting a large amount of heat.

[10] FIG. 2 illustrates a side-view-type LED package according to another conventional art.

[11] A plastic body of the LED package shown in FIG. 2 is similar to the plastic body of the above-described LED package shown in FIG. 1. However, lead frame structures of the LED packages shown in FIG. 1 and FIG. 2 are different from each other. That is, a lead frame of the package shown in FIG. 2 has a plurality of bonding portions, the number of which is in proportional to the number of chips to be enclosed in one package and has a larger number of leads than that of the lead frame of the package shown in FIG. 1. Since the number of leads 23 serving as external terminals is large, the leads 23 should be exposed on a bottom surface (board-mounting surface) of the plastic package 20, particularly along both side edges of the bottom surface. Further, since a cavity wall of the LED package is formed to so thin in order to realize a thin plastic body 20, the bonding portion should preferably occupy a large area in the plastic body 20 to ensure a secure physical fix. However, the leads 23 protruding from the plastic body 20 must be thinner, particularly at a border of the inside and outside of the plastic body 20, than at the other portions, for hermetic sealing at the interface of the plastic body 20 and the lead frame.

[12] Accordingly, due to a relatively large amount of heat accumulated in the package which enclose a plurality of chips, a relatively small size of bonding pad, and a relatively thin lead 23, heat-sinking of the package is hindered, resulting in degradation of performance and reliability of the LED chip.

[13] FIGS. 3 and 4 illustrate a package array and a lead frame array to explain an individualizing process of LED packages by using a saw-cutting method.

[14] FIG. 3 is a package array illustrating the whole arrangement structure of the packages in which four sides of the package should be trimmed. Packages are individualized by the following method.

[15] The package array is attached and fixed to an adhesive film. Both opposing sides of the packages are sawed in one direction, thereby producing package array bars. Next, the other opposing sides of the packages are sawed in a perpendicular direction to the previous direction, so that the package array bar is divided into individual packages.

[16] The above described method has the following problems. After the first direction sawing, the package array is separated into a plurality of package array bars as attached on the adhesive film. During the second direction sawing, the packages may move due to a force exerted when a saw blade pushes the package array bars to saw the package array bars along target sawing lines, so that the packages can be cut at a portion which deviates from the target sawing lines.

[17] Further, the target sawing lines can deviate from their predetermined places in the case in which the adhesive film is partially cut, or due to change of elasticity, which is caused by friction heat generated during the sawing process.

[18] These problems can cause fatal damage to very small LED packages such as side-view-type LED package.

[19] Still further, the sawing method takes a long process time and requires high cost due to frequent replacements of saw blades, which are worn while the method is employed for cutting small size packages and ensuring hermetic sealing of packages by removing mechanical impact generally caused when trimming leads.

[20] FIG. 4 illustrates a lead frame array used for producing the package array in which opposing sides of packages should be cut to individualize the packages. This package array improves the problems of the package array of FlG. 3 but doesn't make a big difference. Disclosure of Invention Technical Problem

[21] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art and to solve the problems, and an object of the present invention is to provide a side-view-type package that is capable of downsizing packages or maintaining the downsizing stream of packages, improving heat-sinking ability, making the Eutetic bonding process easy, improving problems of a conventional package individualizing process which is a sawing method, enhancing board- mounting quality by preventing deviation or inclination of packages when the package are mounted on a board, and enhancing reliability of hermetic sealing.

[22] Further, another object of the present invention is to provide a side- view-type LED package capable of enclosing a plurality of chips such as red, green and blue of three primary light chips therein while maintaining left and right symmetry of a package, the package further capable of being a top- view type LED package as well as being a side-view-type LED package. Technical Solution

[23] In order to achieve the above objects, according to one aspect of the present invention, there is provided a side-view-type LED package, which is a pre-molded plastic package having a plastic body with a cavity which serves as a light reflection and collection cup and which is formed not to overlap with bonding portions of the lead frame, in which an LED chip is mounted on a lead frame, wherein the rectangular parallelepiped, wherein the plastic body comprises a front plane having a cavity which serves as a light-emitting window and through which the bonding portion of the lead frame is exposed, a rear plane for exposing a bottom surface of the lead frame, three side planes sloped and defined by a mold, and a flat plane defined by a saw-cutting method, which would be in contact with a board-mounting surface.

[24] Further the lead frame comprises a lead serving as an electrical terminal, which extends from a bonding pad for wire bonding in the cavity, and comes into contact with and is exposed on the rear plane and the saw-cutting plane of the plastic body, and a multi-function lead serving as an electrical terminal and a heat-sink pad, which extends from a chip-bonding pad on which the LED chip is mounted in the cavity and protrudes from both sides of a long axis of the plastic body.

[25] On the other hand, the lead frame may have no leads in contact with or exposed on the rear plane and the saw-cutting plane of the plastic body, and the chip- bonding pad which is partitioned, in which a portion of the chip-bonding pad is used as a wire-bonding pad, and an extension from the wire-bonding pad is used as a lead serving as an electrical terminal.

[26] Among upper, lower, left and right side planes of the plastic body, the upper and lower planes are formed by a saw-cutting method.

[27] In the package, bottom surfaces of the lead exposed on the rear plane and the multi-function lead extending from both sides of the plastic body are disposed in the horizontal plane with the rear plane of the plastic body, so that the package can be both a side-view-type and a top- view-type package, which uses the bottom surface of the plastic body as a mounting surface.

[28] Further, according to combination and driving method of LED chips to be enclosed in the package, arrangement of the chip bonding pads, the wire-bonding pads and other details of the lead frame are changed, but left-right symmetry structure of the package is maintained. Advantageous Effects

[29] As is apparent from the above descriptions, the side-view-type LED package according to the present invention have the advantages of capable of downsizing a package or maintaining a downsizing stream of a package, enhancing heat-sinking ability, making the Eutetic bonding process easy, improving and solving problems of a package individualizing process of a sawing method, simplifying the package individualizing process, improving board-mounting quality by preventing inclination or deviation of the package when mounting a package on a board, and enhancing reliability in hermetic sealing. Brief Description of the Drawings

[30] FIG. 1 is a perspective view illustrating a side-view-type LED package according to a related art;

[31] FIG. 2 is a perspective view illustrating a side-view-type LED package according to another related art;

[32] FIGS. 3 and 4 are plan views illustrating a package array and a lead frame array, respectively, to explain a sawing method used to separate the package array into a plurality of individual packages;

[33] FIG. 5 is a view illustrating a side-view-type LED package according to a first embodiment of the present invention;

[34] FIG. 6 is a view illustrating a lead frame for use in the side-view-type

LED package according to the first embodiment of the present invention;

[35] FIG. 7 is a view illustrating a plastic body of the side-view-type LED package according to the first embodiment of the present invention; [36] FIGS. 8 and 9 are views illustrating chip arrangement, and a pin-out structure, i.e. terminal configuration of the side-view-type LED package according to the first embodiment of the present invention; [37] FIG. 10 is a view illustrating a side-view-type LED package according to a second embodiment of the present invention; [38] FIG. 11 is a view illustrating a lead frame for use in the side-view-type

LED package according to the second embodiment of the present invention; [39] FIG. 12 is a view illustrating a side-view-type LED package according to a third embodiment of the present invention; [40] FIG. 13 is a view illustrating a lead frame for use in the side-view-type

LED package according to the third embodiment of the present invention; [41] FIG. 14 is a view illustrating a side-view-type LED package according to a fourth embodiment of the present invention; [42] FIG. 15 is a view illustrating a lead frame for use in the side-view-type

LED package according to the fourth embodiment of the present invention; [43] FIG. 16 is a view illustrating a side-view-type LED package according to a fifth embodiment of the present invention; [44] FIG. 17 is a view illustrating a lead frame for use in the side-view-type

LED package according to the fifth embodiment of the present invention; [45] FIG. 18 is a plan view illustrating a package array comprised of the packages shown in FIG. 16.

Best Mode for Carrying Out the Invention [46] Hereafter, embodiments of the present invention will be described with reference to the accompanying drawings. [47] The side-view-type LED package according to the present invention can enclose one or more LED chips therein, and can accommodate all arrangements in which the LED chips are arranged to be driven individually, in parallel or in series.

The LED chip(s) enclosed in the side-view-type package is a single chip emitting a single color of light having the same wavelength, or a plurality of chips emitting different colors of light having different wavelengths. [48] FIG. 5 illustrates a side-view-type LED package according to a first embodiment of the present invention. [49] The LED package encloses red, green and blue of three primary light

LED chips which are driven under different driving conditions, so that the LED package needs at least six terminals to drive the three different kinds of chips individually. [50] From the respect of symmetry of lead arrangement in the LED package, the package includes four chips, in which two chips are the same kind. Further, the package has seven terminals exposed outside the package.

[51] The four chips in the package are arranged to easily realize white color of light when they are simultaneously driven. That is, the chips are preferably arranged in order of red, green, green and blue.

[52] The side-view-type LED package 50 according to the first embodiment of the present invention is a pre-molded plastic package comprising a plastic body 51 with a cavity, in which a light reflection and collection cup is formed not to overlap with bonding portions 52 and 53 for wire bonding of a LED frame, with an LED mounted on a lead frame.

[53] The plastic body 51 is a rectangular parallelepiped. The plastic body 51 comprises a front plane with a cavity 55, serving as a light-emitting window and through which the bonding portions 52 and 53 of the lead frame 60 are exposed, a rear plane through which a bottom of the lead frame 60 is exposed, three sloped side planes 51c and 5 Id defined by a mold, and a flat side plane 5 Ie which is defined by a saw- cutting method and will be in contact with a board-mounting surface.

[54] In order to reduce the size of a package and enhance the heat-sinking ability of the package, the package further comprises five leads 56 extending from wire-bonding pads 52 of the lead frame in the cavity 55, and exposed on and being in contact with the rear plane 51b and a saw-cutting plane 5 Ie of the plastic body 51, a chip-bonding pad bar 54 for mounting the three kinds of four chips in the cavity, and two multi-function leads 57 extending from the chip-bonding pad bar 54, being protruded from both sides 51c of the plastic body and serving as heat-sinking pads as well as electrical terminals.

[55] FIG. 6 illustrates a lead frame used in the side-view-type package according to the first embodiment of the present invention.

[56] The lead frame 60 comprises five leads 56 arranged at regular intervals in a single row, a chip-bonding pad bar 54 having four chip-bonding pads 53 disposed not to overlap with the five leads 56, thereby constituting a saw-tooth shape, two multifunction leads 57 serving as electrical terminals and heat-sinking pads and extending from both ends of the chip-bonding pad bar 54, and a section bar 59 formed in parallel with the chip-bonding pad bar 54 for fixing the five leads 56 and the two multifunction leads 57 in a single row.

[57] In this instance, in order to ensure hermetic sealing between the plastic body 51 and the lead frame 60, when molding the plastic body 51, a rear surface of the chip-bonding pad bar 54 is pressed or etched to a half-thickness thereof, except for portions of the multi-function leads 57. Further, the five leads 56 are also pressed or etched to a half-thickness except for portions exposed on a rear surface of the package as external terminals.

[58] Still further, in order to enhance the heat-sinking ability and to make the

Eutetic bonding process easy, an island 58 may be preferably formed on the pressed or etched rear surface of the chip-bonding pad bar 54 having a half thickness of an initially prepared lead frame, in which the island 58 has the same thickness of the initially prepared lead frame.

[59] FlG. 7 illustrates the plastic body 51 of the package 50.

[60] The plastic body 51 of the package 50 is pre-molded and has a cavity 55 defined by thin cavity walls. The plastic body 51 uncovers a portion of the rear surface of the lead frame, the portion having the original thickness of the lead frame, further uncovers top surfaces and side surfaces of the two multi-function leads 57, and exposes the bonding pads 52 and 53 including the chip-bonding pad 53 and the wire- bonding pad 52 through the cavity 55, and covers at least the section bar 59, the five leads 56 and sides of the chip-bonding pad bar 54

[61]

[62] A method of assembling the side-view-type LED package according to the first embodiment of the present invention comprises the steps of mounting an LED chip on the bonding pads 52 and 53 in the cavity of the pre-molded plastic body, performing wire bonding, filling the cavity 55 with a transparent sealing material, and hardening the transparent sealing material. The method further includes a step of separating the packages by sawing along cutting lines of a package array.

[63] Since the LED package according to the present invention is a side- view-type package, the saw-cutting surface serves as a board mounting-surface. That is, since the saw-cutting surface of the package is the board mounting-surface, the board-mounting surface can be tightly close to a surface of a board, and the package stays horizontal when the package is mounted on a board with high reproducibility.

[64] The external surface of the leads 56 extending on the saw-cutting surface and the rear plane of the plastic body is stably soldered while a solder cream forms a fillet on the external surface. Further, since the multi-function leads 57 have a relatively large area, they are strongly attached over a large space. Accordingly, the multi-function leads 57 prevent the package 50 from being twisted during the soldering process.

[65] Further, due to the foregoing, heat generated from the LED chip can be effectively dissipated to the board. In order to more effectively dissipate heat, the islands 58 on the rear surface of the chip-bonding pad 53 preferably extend to the package mounting-surface and are soldered together with the leads.

[66] FIGS. 8 and 9 illustrate chip arrangement and pin-out structure, respectively, for bonding, according to the most commercially effective examples. [67] Referring to FlG. 8, LED chips emitting three primary colored lights are arranged in order of red, green, green and blue. A second lead and a third lead are used for wire bonding of the red-light LED chip 81, a fourth lead and a chip-bonding pad (a first lead and a seventh lead, respectively) are used for parallel connection of the two green-light LED chips 82, and a fifth lead and a sixth lead are used for wire bonding of the blue-light LED chip 83. By this bonding structure, a full color side- view-type LED package in which the red, green, green and blue-light LED chips can be driven individually can be realized.

[68] In this instance, regardless of the order of colors, two chips for enhancing one color among three colors are preferably disposed in the center of the package and preferably connected parallel to the fourth lead disposed at the center portion of the package and the first and sevenths lead which are the outermost leads, respectively.

[69] FIG. 9 illustrates a side-view-type multi-chip LED package enclosing four chips, which comprise a single type of chips or different types of chips to emit the same color or different colors, and in which the four chips 84 are connected in series by the method of connecting alternately the four chips 84 and wire bonding from second leads to sixth leads.

[70] In this case, the first lead and the seventh lead serving as the multifunction leads 57 function just as heat-sinking pads, but they do not function as electrical terminals.

[71] FIG. 10 illustrates a side-view-type LED package according to a second embodiment of the present invention.

[72] The package shown in FIG. 10 is a full color side-view-type LED package 100 having leads which are symmetrically arranged in left and right sides of the package and includes three different kinds of four chips 114 including red, green, green and blue-light LED chips, which are arranged to be driven parallel.

[73] A plastic body 101 of the package 100 has the feature described below.

[74] Three leads 106 extend from wire-bonding pads 102 disposed in a cavity and are into contact with a rear plane 101b and a saw-cutting plane lOle of the plastic body 101, thereby serving as external terminals. The package 100 further has a chip- bonding pad bar 104 for mounting the three kinds of four chips thereon in the cavity, and two multi-function leads 107 extending from both end portions of the chip- bonding pad bar 104 and protruding from both opposing sides of the plastic body 101 on a long axis of the plastic body 101. The two multi-function leads 107 serve as heat-sinking pads and electrical terminals.

[75] FIG. 11 illustrates an example of a lead frame 110 used to realize the side-view-type LED package according to the second embodiment of the present invention. [76] As shown in FlG. 11, the lead frame 110 comprises three leads 106 arranged in a single row at regular intervals, two chip-bonding pads 103 disposed not to overlap with the leads 106, in which each of the chip-bonding pads has a relatively large size so that two LED chips can be simultaneously mounted thereon, a chip- bonding pad bar 104 for connecting the chip-bonding pads 103, two multi-function leads 107 extending from both end portions of the chip-bonding pad bar 104 to be parallel with the chip-bonding pads 103 and disposed at more outer sides of the chip- bonding pads 103, and a section bar 109 disposed in parallel to the chip-bonding pad bar 104 for fixing and arranging three leads 106 and the two multi-function leads 107 in a single row at regular intervals.

[77] Thickness of the lead frame and contour of a rear surface of the lead frame are configured in the same way as the lead frame of the side-view-type LED package of the first embodiment.

[78] The side-view-type LED package according to the second embodiment of the present invention can be assembled by the following method.

[79] At the first, LED chips 114 are grouped: a first group including a red-light chip and a green-light chip and a second group including a green-light chip and a blue- light chip. Each group of the LED chips 114 are mounted on each chip-bonding pad 103. Then, wire bonding is performed.

[80] FIG. 12 illustrates a side-view-type LED package according to a third embodiment of the present invention.

[81] The LED package shown in FlG. 12 is a full-color side-view-type LED package including three LED chips, which are different kinds and are driven individually, in which leads are arranged symmetrically at left and right sides of the package.

[82] The LED package 120 includes a plastic body 121, four leads 127 serving as electrical terminals and being in contact with a rear plane and a saw-cutting plane of the plastic body 121 and exposed outside the plastic body 121, three chip-bonding pads 123, 124 and 125 in which the chip-bonding pad 123 is physically separated from the other chip-bonding pads 124 and 125, a chip-bonding pad bar 126 for connecting the chip-bonding pads 124 and 125, and two multi-function leads 128 extending from both end portions of the chip-bonding pad bar 126, being exposed outside the plastic body 121 and protruding from left and right sides of the plastic body 121, and serving as heat sink pads as well as electrical terminals.

[83] FIG. 13 illustrates a lead frame 130 for use in the side-view-type LED package according to the third embodiment of the present invention.

[84] As shown in FIG. 13, the lead frame comprises four leads 127, three chip- bonding pads 123, 124 and 125 formed not to overlap with the four leads 127, in which the chip-bonding pad 123 is separated from the other chip-bonding pads 124 and 125, a chip-bonding pad bar 126 connecting the two chip-bonding pads 124 and 125, two multi-function leads 128 extending from the chip-bonding pad 123 and one end portion of the chip-bonding pad bar 126, respectively, and being disposed at more outer sides of the four leads 127, and a section bar 129 for fixing the four leads 127 and two multifunction leads 128 as the four leads 127 and the two multi-function leads 128 are arranged in a single row, in which the section bar 129 is disposed below away from the chip-bonding pad bar 126 and the chip-bonding pad 123 by a distance.

[85] Here, thickness and contour of a rear surface of the lead frame are configured in the same way as the lead frame of the side-view-type LED packages according to the first and second embodiments of the present invention.

[86] The package according to the third embodiment of the present invention is assembled in the above described method.

[87] Here, the three different kinds of LED chips 131 are wire-bonded to be driven individually, as shown in FIG. 12.

[88] FIG. 14 illustrates a side-view-type LED package according to a fourth embodiment of the present invention.

[89] As shown in FIG. 14, the side-view-type LED package encloses a single

LED chip.

[90] The package 140 includes a chip-bonding pad 143 disposed in a cavity of a plastic body for mounting a LED chip thereon, a wire-bonding pad 142 disposed adjacent to the chip-bonding pad 143, a multi-function lead 147 extending from the chip-bonding pad, protruding from a side on a long axis of the plastic body and serving as a heat-sinking pad as well as an electrical terminal, and a lead 146 extending from the wire-bonding pad, protruding from the other side on the long axis of the plastic body and serving only as an electrical terminal.

[91] As shown in FIG. 15, the lead frame 150 for use in the package according to the fourth embodiment of the present invention comprises a chip-bonding pad 143 and a wire-bonding pad 142 which are arranged to be adjacent to each other, leads 147 and 146 extending in parallel from opposing edges of the chip-bonding pad 143 and the wire-bonding pad 142, respectively, and a section bar 149 for fixing the chip- bonding pad 143 and the wire-bonding pad 142 in a single row.

[92] Rear surfaces of the chip-bonding pad 143 and the wire-bonding pad 142 are pressed or etched to a half-thickness, so that thickness of the chip-bonding pad 143 and the wire-bonding pad 142 become a half of the original thickness of the lead frame. Further, islands 148 are preferably formed on the rear sides of the chip-bonding pad 143, so that the total thickness of the chip-bonding pad 143 including island is the same as the original thickness of the lead frame and this embodiment has the advantage of the Eutectic bonding process.

[93] FIG. 16 illustrates a side-view-type LED package according to a fifth embodiment of the present invention.

[94] The side-view-type LED package 160 shown in FIG. 16 includes a single

LED chip therein.

[95] The package(160) ,which is a pre-molded plastic package having a plastic body with a cavity which serves as a light reflection and collection cup and which is formed not to overlap with bonding portions of the lead frame, in which an LED chip is mounted on a lead frame(170), wherein the rectangular parallelepiped plastic body(161) comprises a front plane(161a) with a cavity which serves as a light-emitting window, and through which the bonding portions of the lead frame are exposed; a rear plane(161b) through which a bottom surface of the lead frame is exposed; a left-side plane and a right-side plane(161c) which are defined by a mold and sloped; and an upper side plane(161d) and a lower side plane(161e) which are horizontally flatted and defined by a saw-cutting method.

[96] Locations of leads of the lead frame are described in relation with the plastic body 161. That is, the lead frame comprises a chip-bonding pad 163 for mounting an LED chip thereon, which is disposed in the cavity, a wire-bonding pad 162 disposed next to the chip-bonding pad 163, a multi-function lead 167 extending from the chip-bonding pad 163, protruding from a side 161c on a long axis of the plastic body 161 and serving as an electrical terminal and a heat sink pad, and a lead 166 extending from the wire-bonding pad, protruding from the other side of the plastic body 161 on the long axis and serving as an electrical terminal.

[97] As shown in FIG. 17, the lead frame 170 for the package 160 comprises a plurality of unit frames which are arranged in parallel, and in which each unit frame comprises two opposing sections bars 169 disposed away from each other by a distance, a chip-bonding pad 163 extending from one section bar 169, called a first section bar, of the section bars 169 toward the other section bar 169, called a second section bar 169, a wire-bonding pad 162 extending from the second section bar 169 toward the first section bar 169, so that the chip-bonding pad 163 and the wire-bonding pad 162 are disposed between the two section bars 169 and adjacent to each other, in which the chip-bonding pad 163 and the wire-bonding pad 162 are called the bonding portions. Further the chip-bonding pad 163 and the wire-bonding pad 162 are pressed or partially etched on a rear surface thereof to a half-thickness.

[98] Here, an island 168 can be formed on the rear surface of the chip-bonding pad. In this case, the total thickness of the chip-bonding pad including the island is the same as the thickness of the original lead frame.

[99] FIG. 18 illustrates a package array 180 in which a plurality of packages are arranged on the lead frame 170 as they are not separated into individual packages.

[100] As shown in FlG. 18, the plastic body uncovers the entire lower surface of the lead frame, and further uncovers the front surface and external side surfaces of the two section bars 169. The plastic body is a pre-molded plastic body disposed between the section bars 169 to cover a plurality of unit frames of the lead frame, while exposing the bonding portions 162 and 163 of each package through each cavity.

[101] The packages shown in FlG. 16 are assembled such that each LED chip is mounted on the bonding portions 163 and 162 in each cavity, wire bonding is performed, each cavity is filled with a transparent liquid resin, the resin is hardened, and the packages in the package array are separated into individual packages by sawing the package array along cutting lines 181. Industrial Applicability

[102] The packages according to embodiments of the present invention can accommodate a variety of chip arrangements and have a saw-cutting plane as a board-mounting surface. In order to realize the foregoing, the thickness of the lead frame is technically the same as the thickness of a rear portion of the package, excluding a height of the cavity of a front portion of the package. The thickness is important from the viewpoint of reliability in mechanical strength, moisture absorption and heat-sink characteristics. Accordingly, as long as it is allowable in the respect of LED chip arrangements and technologies, the lead frame is preferably as thick as possible.

[103] The package according to the present invention can be used as a light source of a back-light to improve image quality of medium-sized and small-sized liquid crystal displays. Further, the package is excellent in heat-sinking and can accommodate multi-chip structure. Accordingly, the package according to the present invention can be applied diversely.

[ 104] Although preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claim.

Claims

[1] A side-view-type LED package, which is a pre-molded plastic package having a plastic body with a cavity which serves as a light reflection and collection cup and which is formed not to overlap with bonding portions of the lead frame, in which an LED chip is mounted on a lead frame, wherein the rectangular parallelepiped plastic body comprises: a front plane having a cavity which serves as a light-emitting window and through which the bonding portion of the lead frame is exposed; a rear plane for exposing a bottom surface of the lead frame; three side planes sloped and defined by a mold; and a flat plane defined by a saw-cutting method, which would be in contact with a board-mounting surface.

[2] The side-view-type LED package as claimed in claim 1, wherein the plastic body has an upper-side plane, a lower-side plane, a left-side plane, and a right-side plane, in which the upper- and lower-side planes are flat planes and a saw-cutting plane adds to the four side planes.

[3] The side-view-type LED package as claimed in claim 1, wherein the lead frame comprises: a lead serving as an electrical terminal, which extends from a bonding pad for wire bonding in the cavity, and comes into contact with and exposed on the rear plane and the saw-cutting plane of the plastic body; a multi-function lead serving as an electrical terminal and a heat sink pad, which extends from a chip-bonding pad on which the LED chip is mounted in the cavity and protrudes from both sides of a long axis of the plastic body.

[4] The side-view-type LED package as claimed in claim 1, wherein the lead frame comprises: a plurality of leads, serving as electrical terminals and being used for wire bonding, which are arranged in a single row; a chip-bonding pad bar for connecting chip-bonding pads disposed not to overlap with the leads, the chip-bonding pad bar having a saw-tooth shape; two multi-function leads serving as electrical terminals and heat-sink pads, which are formed to extend from both end portions of the chip-bonding pad bar; and a section bar for fixing the leads and the multi-function leads in a single row, the section bar being disposed in parallel with and below and away from the chip-bonding pad bar.

[5] The side-view-type LED package as claimed in claim 4, wherein a rear surface of the chip-bonding pad bar is partially pressed or etched to a half- thickness except for portions where the multi-function leads are formed, and rear surfaces of bonding portions of the leads are pressed or etched to a half thickness thereof, except for portions exposed on a rear surface of the package as external terminals.

[6] The side-view-type LED package as claimed in claim 5, wherein an island is formed on the pressed or etched rear surface of the chip-bonding pad bar having a half thickness of an initially prepared lead frame, in which the island has the same thickness of the initially prepared lead frame.

[7] The side-view-type LED package as claimed in claim 1, wherein no leads are either in contact with or exposed on the rear plane and the saw-cutting plane of the plastic body, and the chip-bonding pad is partitioned, so that a portion of the chip-bonding pad is used as a wire-bonding pad, and an extension from the other portion of the chip-bonding pad is used as a lead serving as an electrical terminal, in the case in which the package includes a single LED chip therein.

[8] The side-view-type LED package as claimed in claim 1, wherein leads exposed on the rear plane of the plastic body and a bottom surface of a multifunction lead protruding from the sides of the plastic body are in a horizontal plane with a rear surface of a body of the package, so that the rear surface of the package body is used as the board-mounting surface, wherein in this case, the package are used as both top-view type and side-view-type packages.

[9] The side-view-type LED package as claimed in claim 4, wherein in the case in which the package encloses a set of three different kinds of four LED chips, the set including a red-light LED chip, a green-light LED chip, a green- light LED chip and a blue-light LED chip, or a set of a single kind of four chips, and the set of chips are driven individually or in series, the lead frame comprises: five leads arranged in a single row at regular intervals; a chip-bonding pad bar connecting four chip bonding pads disposed not to overlap with the five leads and having a shape of teeth of a saw; and two multi-function leads extending from both end portions of the chip- bonding pad bar and disposed at more outer sides of the outermost leads among the leads, respectively.

[10] The side-view-type LED package as claimed in claim 4, wherein, in the case in which the package encloses a set of three different kinds of four LED chips, the set including a red-light LED chip, a green-light LED chip, a green- light LED chip and a blue-light LED chip, and the set of chips are driven parallel, the lead frame comprises: three leads arranged in a single line at regular intervals; a chip-bonding pad bar for connecting two chip-bonding pads disposed not to overlap with the three leads, in which each of the two chip-bonding pads has a large size so that two chips can be mounted thereon; and two multi-function leads extending from both end portions of the chip- bonding pad bar and disposed at more outer sides of the outermost leads, respectively.

[11] The side-view type LED package as claimed in claim 4, wherein in the case in which the package encloses a set of three different kinds of three LED chips, the set including a red-light LED chip, a green-light LED chip, and a blue- light LED chip, and the set of chips are driven individually, the lead frame comprises: four leads arranged in a single line at regular intervals; a separate chip bonding pad among three chip bonding pads disposed not to overlap with the four leads; a chip-bonding pad bar for connecting two chip-bonding pads except for the separate chip bonding pad disposed not to overlap with the three leads, the chip-bonding pad bar having a saw tooth shape; and two multi-function leads extending from both end portions ofthe separate chip bonding pad and the chip bonding pad bar and disposed at more outer sides of the outermost leads, respectively.

[12] A side-view-type LED package, which is a pre-molded plastic package having a plastic body with a cavity which serves as a light reflection and collection cup and which is formed not to overlap with bonding portions of the lead frame, in which an LED chip is mounted on a lead frame, wherein the rectangular parallelepiped plastic body comprises: a front plane with a cavity which serves as a light-emitting window, and through which the bonding portions of the lead frame are exposed; a rear plane through which a bottom surface of the lead frame is exposed; a left-side plane and a right-side plane which are defined by a mold and sloped; and an upper side plane and a lower side plane which are horizontally flatted and defined by a saw-cutting method.

[13] The side-view-type LED package as claimed in claim 12, wherein the lead frame comprises: two section bars arranged in parallel; and two bonding portions extending from the two section bars, respectively to be disposed between the two section bars and adjacent to each other, in which the bonding portions are divided into a chip-bonding pad and a wire-bonding pad, and are pressed or etched at a rear surface thereof to a half thickness, wherein the bonding portions constitute a set, and a plurality of the bonding portion sets is arranged in parallel at regular intervals. [14] The side-view-type LED package as claimed in claim 13, further comprising an island on the rear side of the chip-bonding pad, and the island has an initial thickness of the lead frame.