KR100691178B1 - Side-view led having led chip placed behind lead frame - Google Patents

Abstract

The present invention relates to a side type LED. The LED has a lead frame; An LED chip attached to one surface of the lead frame and electrically connected to the lead frame; And a package body formed on the opposite side of the LED chip from the lead frame to surround the lead frame and at least a portion of the LED chip so that light of the LED chip enters the recess through the lead frame. do. Therefore, miniaturization of the LED can be achieved without lowering reliability or losing performance.

LED, Side Type, Leadframe, Opening, Die Bonding

Description

Side-side light emitting diode with light emitting diode chip placed behind lead frame {SIDE-VIEW LED HAVING LED CHIP PLACED BEHIND LEAD FRAME}

1 is a side view of a backlight device equipped with a side type LED.

2 is a front view showing an example of the LED of the prior art.

3 is a cross-sectional view taken along the line III-III of FIG. 2.

4 is a front view of a side type LED according to the first embodiment of the present invention.

5 is a cross-sectional view taken along the line V-V of FIG. 4.

Figure 6 is a plan view showing a state in which the LED chip is mounted on the lead frame in the side type LED according to the present invention.

FIG. 7 is a cross-sectional view illustrating a modification of the side LED of FIG. 5.

8 is a plan view illustrating a state in which an LED chip is mounted on a lead frame in a side type LED according to a second exemplary embodiment of the present invention.

9 is a plan view illustrating a state in which an LED chip is mounted on a lead frame in a side type LED according to a third exemplary embodiment of the present invention.

10A to 10J are cross-sectional views illustrating a side type LED manufacturing process according to a first embodiment of the present invention.

<Explanation of symbols of main parts in drawings>

100: side type LED 110: package body

112: recess 120, 120-2, 120-3, 122: lead frame

124: opening 124-2: indentation

130: LED chip 132: adhesive

132-1: adhesive film 140: transparent resin

The present invention relates to a side light emitting diode (LED), and more particularly to a side LED that can achieve miniaturization without deteriorating reliability or performance by placing the LED chip behind the lead frame.

Small LCDs such as mobile phones and PDAs use side-by-side LEDs as the light source for their backlight devices. Such side type LEDs are typically mounted on a backlight device as shown in FIG. 1.

Referring to FIG. 1, in the backlight device 50, a flat light guide plate 54 is disposed on a substrate 52, and a plurality of side type LEDs 1 (shown only one side) are arranged in an array form on the side of the light guide plate 54. Is placed. The light L incident from the LED 1 to the light guide plate 54 is reflected upward by a fine reflection pattern or a reflective sheet 56 provided on the bottom surface of the light guide plate 54 and exited from the light guide plate 54, and then the light guide plate ( 54) The backlight is provided to the upper LCD panel 58.

FIG. 2 is a front view showing an example of the LED 1 of the prior art as shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line III-III of FIG.

2 and 3, the LED 1 includes a package body 10, a pair of lead frames 20 and 22 disposed in the package body 10, and an LED chip mounted on the lead frame 20 ( 30).

The package body 10 is usually formed by molding a high reflectance resin, and can be divided into a front half portion 10a and a second half portion 10b around the lead frames 20 and 22. The first part 10a is formed with a recess 12 and a wall 14 around it. The recess 12 has a V-shape with a flat bottom and widening forwardly, i.e., the upper direction of FIG. This is to guide the light generated from the LED chip 30 in the direction of the arrow (A) of FIG. Due to the shape of the recesses 12, the wall 14 becomes narrower toward the tip 16.

In addition, the inside of the recess 12 is filled with a transparent resin 40 to seal the LED chip 30 from the outside. On the other hand, the resin may contain a fluorescent material for converting the light or ultraviolet light generated by the LED chip 30 to, for example, white light.

Meanwhile, the LED chip 30 is electrically connected to the lead frames 20 and 22 by wires W, and some of the lead frames 20 and 22 extend outside the package body 10 to form external terminals. .

The mounting height of these side type LEDs is gradually decreasing, and it is expected that a dimension of 0.5 mm or less will be required in the future. In addition, the side-type LED must secure high reliability, and should realize high brightness by minimizing light loss.

At present, a method for reducing the thickness reduction of the side-side LED is focused on reducing the thickness of the upper and lower portions of the recess 12 (shown in FIG. 2) of the wall 14. However, if the thickness of the wall 14 is reduced, in particular, the tip 16a of the upper and lower portions of the recess 12 is extremely thin, which tends to cause a problem such as brittleness and an unmolded portion.

On the other hand, it is also possible to reduce the thickness of the side-shaped LED (1) by reducing the width of the LED chip (30). However, when the width of the LED chip 30 is reduced and lengthened, there is a problem that the efficiency is lowered.

Further, even if the width of the LED chip 30 is reduced, the width of the recesses 12, in particular the bottom 18 of the wall 14, becomes narrower as the thickness of the side-shaped LEDs 1 decreases. In this case, the operation of attaching the LED chip 30 to the lead frame 20 after the package body 10 forming operation should be performed in a narrower space. As a result, the task becomes difficult and the available equipment must be further miniaturized. Considering that the total thickness currently required for side-side LEDs is currently 0.7 mm or less, which will be further reduced, it can be seen that even if the width of the LED chip is reduced, difficult problems still occur.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a side type LED that can be easily manufactured by placing the LED chip behind the lead frame.

It is another object of the present invention to provide a side type LED which can be miniaturized without reducing the reliability of reducing the wall thickness around the recess of the LED by placing the LED chip behind the lead frame.

Another object of the present invention is to provide a side type LED that can be miniaturized without losing performance by reducing the width of the LED chip by placing the LED chip behind the lead frame.

In order to achieve the above object of the present invention, the present invention provides a pair of lead frames; An LED chip attached to one surface of the pair of lead frames and electrically connected to the lead frame; And a package body formed on the opposite side of the LED chip from the lead frame to surround the lead frame and at least a portion of the LED chip, wherein the lead frame to which the LED chip is attached exposes a portion of the LED chip. An exposed space is formed to provide a side type light emitting diode configured to allow light of the LED chip to enter the recess through the lead frame.

The exposed space may be formed as an opening through which light of the LED chip passes through the recess. In this case, the opening is formed in a region corresponding to the LED chip, it characterized in that the area is smaller than the LED chip. In addition, the edge of the opening is characterized in that it partially overlaps with the bottom edge of the recess.

In addition, the exposure space may be formed in a shape that is indented in a region corresponding to the LED chip to pass a light of the LED chip while supporting a portion of the edge of the LED chip. At this time, the edge of the exposed space is characterized in that it partially overlaps with the bottom edge of the recess.

In addition, the pair of lead frames may be configured to support both ends of the LED chip apart from each other shorter than the length of the LED chip so that the light of the LED chip passes.

In addition, the width of the LED chip is larger than the width of the bottom surface of the recess of the package body.

Meanwhile, the side type light emitting diode may further include a reflective coating formed on an opposite surface of the LED chip.

In addition, the side light emitting diode may further include a transparent adhesive provided between the LED chip and the lead frame. At this time, the adhesive is characterized in that the adhesive film.

On the other hand, the package body is characterized in that consisting of a reflector.

The side light emitting diode may further include a second lead frame disposed adjacent to the LED chip at a distance from the lead frame and electrically connected to the LED chip.

In addition, the side type light emitting diode may further include a transparent resin provided in a recess of the package body.

In the LED chip, a p-electrode is formed on a surface opposite to the lead frame opening, and the p-electrode may be made of Ag, Al, Pd, Rh, and an alloy thereof.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a front view of a side type LED according to a first embodiment of the present invention, FIG. 5 is a cross-sectional view taken along the line VV of FIG. 4, and FIG. 6 is a lead frame of the LED chip in the side type LED according to the present invention. This is a plan view showing the state of being mounted on.

4 to 6, the side type LED 100 according to the present invention is connected to a package body 110, a pair of lead frames 120 and 122 and a lead frame 120 disposed in the package body 110. It includes an LED chip 130 mounted.

The package body 110 is usually formed by molding a high reflectance polymer, and may be divided into a first half 110a and a second half 110b around the lead frames 120 and 122. In the first half 110a, a recess 112 and a wall 114 around the recess 112 are formed. The recess 112 has a flat V-shape with a flat bottom and widening in the forward direction, i.e., the upper direction of FIG. This is to guide the light generated from the LED chip 130 to the upper direction of FIG. Due to the shape of the recess 112, the wall 114 decreases in thickness toward the tip 116.

The LED chip 130 is attached to a surface opposite the recess 112 of the lead frame 120, and a portion of the LED chip 130 is exposed to a region corresponding to the LED chip 130 to expose the LED chip 130. An exposed space is formed to allow light to pass through. In the present embodiment, a case in which the exposed space is applied to the through hole opening 124 will be described. The opening 124 is formed to pass light generated in the LED chip 130 in the direction of arrow A of FIG. 5, and a part of the lead frame 120 around the opening 124 is formed of the LED chip 130. It is supporting the edge.

Meanwhile, a transparent adhesive 132 is provided in the contact surface and the opening 124 of the lead frame 120 and the LED chip 130 to couple the lead frame 120 and the LED chip 130 to each other. Since the adhesive 132 is transparent, light emitted from the LED chip 130 is passed in the direction of arrow A of FIG. 5.

At this time, the LED chip 130 is electrically connected to the lead frames 120 and 122 by the wire (W), the lead frame 120, 122 is partially extended outside the package body 22 is connected to the external power source Form an external terminal.

In addition, the inside of the recess 112 is filled with a transparent resin 140 such as epoxy to seal the LED chip 130 from the outside.

In this configuration, the light generated from the LED chip 130 passes through the transparent adhesive 132 filled in the opening 124 of the lead frame 120 and the transparent resin 140 of the recess 112. Is emitted in the direction.

At this time, the light generated from the LED chip 130 is reflected by the p-electrode (not shown) formed on the bottom surface of the LED chip 130, that is, the area opposite to the arrow A, in the direction of the arrow A. Proceed. Since the p-electrode of the LED chip 130 is made of a high reflectance metal, preferably Ag, Al, Pd, Rh and alloys thereof, the light generated in the LED chip 130 can be effectively reflected in the direction of the arrow A. have.

Of course, a high reflectivity coating may be formed on the bottom surface of the LED chip 130 to improve efficiency.

On the other hand, making the package body 110 a high reflectance polymer may further improve the light induction function by the wall 114 while further improving the above reflection efficiency. Examples of high reflectivity polymers include the product names NM114WA and NM04WA from Otsuka Chemical Co., Ltd. These materials are suitable as the material of the package main body 110 of the present invention because they exhibit high reflectance even at a high temperature of approximately 180 ° C.

The side type LED 100 of the present invention may be used as a monochromatic light source, but may also be used as a white light source. In this case, it may be advantageous to convert the light of the LED 100 to white light using a fluorescent material rather than to obtain a white light source by combining RGB LEDs.

In this case, it is preferable to add a fluorescent material and / or an ultraviolet absorber for converting light generated from the LED chip 130 to the transparent resin 140. Alternatively, the fluorescent material and / or ultraviolet absorber may be coated or applied to the surface of the LED chip 130. As another method, it is also possible to add one of the fluorescent material and the ultraviolet absorber to the transparent resin 140 and provide the other to the surface of the LED chip 130.

On the other hand, as shown in FIG. 4, the opening 124 of the lead frame 120 has a long side surface having a predetermined distance G from the bottom edge 118 of the recess 112. This gap G can be reduced, and as the gap G is reduced, the opening 124 becomes larger, thereby increasing the area where the LED chip 130 is exposed. Most preferably, the edge of the opening 124 is formed to coincide with the bottom edge of the recess 112.

In addition, referring to FIG. 6, the width of the LED chip 130 may also increase as the gap G is reduced. In this case, the width of the LED chip 130 may be larger than the bottom edge of the recess 112.

That is, the exposure width of the LED chip 130 may be increased by reducing the gap G as described above. In other words, this means that the thickness of the side type LED 100 can be further reduced when the width of the LED chip 130 is constant.

As such, when the LED chip 130 is disposed behind the lead frame 120 from the recess 112, there are advantages as follows.

Conventionally, after molding a package main body using a metal mold | die, the LED chip was put into the recessed part, and it mounted in the lead frame. Therefore, it is cumbersome to perform the LED chip mounting work in the narrow recesses. However, the side type LED 100 of the present invention forms the package body 110 in a state where the LED chip 130 is first mounted on the lead frame 120, thereby solving the problems of the prior art.

In addition, in the related art, in order to reduce the thickness of the side LED while maintaining the width of the recess, the thickness of the upper and lower walls of the recess must be reduced, which lowers the reliability of the side LED. On the other hand, according to the present invention, since the package body 110 is formed in the state in which the LED chip 130 is first mounted on the lead frame 120, it is not necessary to reduce the thickness of the wall 114 above and below the recess 112. Therefore, in the molding operation, the resin is smoothly supplied to the upper and lower front ends 116a of the wall 114, thereby solving the conventional molding problem.

On the other hand, although the LED chip can be made thinner in order to reduce the thickness of the side-side LED, this reduces the chip performance. However, the present invention can reduce the thickness of the side type LED 100 without reducing the width of the LED chip 130. Therefore, the performance of the LED chip 130 does not fall.

Of course, some of the LED chip 130 may have a disadvantage that is covered by the lead frame 120, but this is insignificant compared to the degradation of the LED chip 130. In particular, as described above, the area covered by the LED chip 130 can be reduced by minimizing the gap G between the edge of the lead frame opening 124 and the bottom edge 118 of the recess 112. Can be minimized. In addition, as described above, since the package body 110 surrounding the bottom and side surfaces of the LED chip 130 is made of a high reflectivity polymer, light generated at the edge of the LED chip 130 is also reflected by the package body 110. Proceed in the direction of the arrow (A). Therefore, it can be seen that the light loss is not large.

As another advantage of the present invention, the transparent resin 140 of the recess 112 can be omitted. That is, since the electrode side and the wire W of the LED chip 130 are encapsulated by the package body 110, the LED chip 130 and the wire W may be protected from the outside even without the transparent resin 140. have.

In addition, even if the transparent resin 140 is provided only at the bottom of the recess 112, a desired effect can be achieved.

FIG. 7 is a cross-sectional view illustrating a modification of the side LED of FIG. 5.

Referring to FIG. 7, the side type LED 100a may include an LED chip 130 attached to the lead frame 120 by an adhesive film 132-1 and a transparent resin (eg, an opening 124 in the lead frame 120). It is substantially the same as the side type LED 100 of the first embodiment of FIG. 5 except that 140 is filled. Therefore, the remaining matters are the same as those of the side type LED 100 of the first embodiment described above, and further description thereof will be omitted.

8 is a plan view illustrating a state in which an LED chip is mounted on a lead frame in a side type LED according to a second exemplary embodiment of the present invention.

Referring to FIG. 8, the exposure space formed in the lead frame 120-2 is different from the first embodiment described above in that the exposed space is applied to the indentation 124-2. The edge of the indent 124-2 is coupled to and supports the edge of the LED chip 130, and a part of the indent 124-2 (lower direction in the drawing) is open. In this way, the indentation 124-2 exposes more area of the LED chip 130 toward the recess of the package body (see reference numeral 112 in FIGS. 4 and 5) than the opening 124 of the first embodiment. do. Therefore, the amount of light traveling toward the recess of the package body in the LED chip 130 can be increased.

The rest of the configuration except for the indentation 124-2 is substantially the same as that of the side type LED 100 of the first embodiment of FIG. 5. Therefore, the remaining matters are the same as those of the side type LED 100 of the first embodiment described above, and further description thereof will be omitted.

9 is a plan view illustrating a state in which an LED chip is mounted on a lead frame in a side type LED according to a third embodiment of the present invention.

Referring to FIG. 9, the pair of lead frames 120-3 and 122 are coupled to both ends of the LED chip 130 at intervals shorter than the length of the LED chip 130. The LED chip 130 may be fixedly attached to the lead frames 120-3 and 122 using the adhesive described above in the first embodiment. In addition, the LED chip 130 is electrically connected to the lead frames 120-3 and 122 by the wire (W). In addition, the part shown with the double-dashed line shows the bottom edge of the recessed part (refer to 112 of FIGS. 4 and 5).

The third embodiment of such a configuration has a larger area of the LED chip 130 than the opening 124 of the first embodiment or the indentation 124-2 of the second embodiment, so that the recess of the package body (Fig. 4 and (See reference numeral 112 of FIG. 5). Therefore, the amount of light traveling toward the recess of the package body in the LED chip 130 can be increased.

Except for this, the rest of the configuration is substantially the same as the side type LED 100 of the first embodiment of FIG. Therefore, the remaining matters are the same as those of the side type LED 100 of the first embodiment described above, and further description thereof will be omitted.

Hereinafter, a side type LED manufacturing process of the present invention will be described with reference to FIGS. 10A to 10J with reference to the side type LED 100 according to the first embodiment shown in FIGS. 4 to 6.

First, as shown in FIGS. 1A and 1B, the first and second lead frames 120 and 122 are disposed on the pad 160. Although these lead frames 120a and 120b are shown separately in the figures, they may be provided integrally as part of one large frame sheet.

Subsequently, as illustrated in FIG. 1C, a transparent adhesive 132 is injected into the opening 124 of the first lead frame 120. The adhesive 132 discharges an appropriate amount using, for example, a precision syringe.

Then, the LED chip 130 is deposited on the adhesive 132, and the adhesive 132 is cured to fix the LED chip 130 to the lead frame 120 (FIGS. 1D and 1E). At this time, preferably, the LED chip 130 may be bonded to the lead frame 120 by pressing in a die bonding manner, that is, at an appropriate pressure.

Subsequently, as shown in FIGS. 10F and 10G, the LED frame 130 and the lead frames 120 and 122 may be electrically connected to each other by a wire W to combine the lead frames 120 and 122 and the LED chip 130, respectively. Get

Then, as shown in FIG. 10H, the pads 160 are removed from the lead frame 124, 122-LED chip 130 combination in the direction of the arrow A. FIG.

Subsequently, the lead frame 124, 122-LED chip 130 combination is put into a mold and resin is injected to obtain a package body 110 as shown in Fig. 10I.

Then, as shown in FIG. 10J, the transparent resin 140 is filled and cured in the recess 112 of the package body 110. The transparent resin 140 can be preferably formed by transfer molding. Alternatively, the transparent resin 140 may be formed by discharging an appropriate amount of resin into the recess 112 by using a precision syringe or the like.

After this step, the outer ends of the first and second lead frames 120 and 122 are bent to obtain side type LEDs 100 as shown in FIGS. 4 and 5. Of course, when using the frame sheets provided with the first and second lead frames 120 and 122 integrally as described above, these lead frames 120 and 122 are cut from the frame sheets and then the above bending operation is performed. do.

When the molding operation is performed in the state in which the LED chip 130 is attached to the lead frame 120 as described above, after the molding of the package body as in the prior art, a complicated operation of putting the LED chip in the narrow recess to mount the lead chip on the lead frame is performed. You do not have to do. Therefore, the work process is easy and the productivity is improved.

As described above, the side type LED of the present invention can be easily manufactured by placing the LED chip behind the lead frame. Further, by arranging the LED chip behind the lead frame, it is possible to miniaturize the side type LED without reducing the reliability of reducing the wall thickness around the recess of the LED. In addition, side LEDs can be miniaturized without compromising the performance of reducing the width of the LED chip.

Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art may vary the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be understood that modifications and variations can be made.

Claims (15)

A pair of lead frames; An LED chip attached to one surface of the pair of lead frames and electrically connected to the lead frame; And A recess formed on the opposite side of the LED chip from the lead frame, the package body surrounding at least a portion of the lead frame and the LED chip; The lead frame to which the LED chip is attached is formed with an exposed space for exposing a portion of the LED chip, so that the light of the LED chip is configured to enter the recess through the lead frame. The side type light emitting diode of claim 1, wherein the exposure space is an opening through which light of the LED chip passes through the recess. The side type light emitting diode of claim 2, wherein the opening is formed in a region corresponding to the LED chip and has a smaller area than the LED chip. The side type light emitting diode of claim 2, wherein an edge of the opening partially overlaps a bottom edge of the recess. The method of claim 1, wherein the exposure space, the lead frame is formed in a shape that is indented in a region corresponding to the LED chip to pass the light of the LED chip while supporting a portion of the edge of the LED chip. Side type light emitting diode. The side light emitting diode of claim 5, wherein an edge of the exposed space partially overlaps a bottom edge of the recess. A pair of lead frames; An LED chip attached to one surface of the pair of lead frames and electrically connected to the lead frame; And A recess formed on the opposite side of the LED chip from the lead frame, the package body surrounding at least a portion of the lead frame and the LED chip; And the pair of lead frames support both ends of the LED chip apart from each other shorter than the length of the LED chip so that light of the LED chip passes therethrough. The side type light emitting diode according to claim 1 or 7, wherein a width of the LED chip is larger than a width of a bottom surface of the recess of the package body. The side type light emitting diode of claim 1, further comprising a reflective coating formed on an opposite surface of the LED chip. The side type light emitting diode according to claim 1 or 7, further comprising a transparent adhesive provided between the LED chip and the lead frame. The side type light emitting diode of claim 10, wherein the transparent adhesive is an adhesive film. The side type light emitting diode of claim 1 or 7, wherein the package body is formed of a reflector. delete 8. The side light emitting diode according to any one of claims 1 to 7, further comprising a transparent resin provided in a recess of the package body. 8. The LED chip of claim 1 or 7, wherein the LED chip has a p-electrode formed on a surface opposite the lead frame opening, and the p-electrode is composed of Ag, Al, Pd, Rh, and alloys thereof. Side type light emitting diode.

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