JPH05299702A - Led array - Google Patents

Abstract

PURPOSE:To provide a LED array which makes it feasible to miniaturize the device in which the LED array is incorporated with the width of its mounting printed board reduced and at the same time to reduce its cost. CONSTITUTION:In a LED array in which a first conductive pattern 12 for mounting a plurality of LED chips provided along the direction of the length on a long printed board 11 and a second conductive pattern 13 for a plurality of connections provided along the direction of the length in close proximity to each first conductive pattern 12 are formed, and the other surface than the first and the second conductive pattern is coated with a resist, and then a LED chip 14 is mounted on the first conductive pattern 12 and then fixed by die- bonding, and the upper surface of each LED chip 14 and the second conductive pattern 13 corresponding thereto are connected by a bonding wire 15, a white resist 18 is used for the resist.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED array used as a line light source for an eraser of an electronic copying machine or a reading line light source for an LED printer, a facsimile machine or the like.

[0002]

2. Description of the Related Art Conventionally, such an LED array is shown in FIG.
It is configured as shown in. That is, the LED array 1
Is a plurality of first conductive patterns 3 for mounting LED chips arranged along the longitudinal direction of the long printed circuit board 2 and lateral to each first conductive pattern 3. And a plurality of second conductive patterns 4 for connection, which are arranged in the longitudinal direction of the printed circuit board 2 and are formed, and the first conductive pattern 3 and the second conductive pattern 4 are bonded. The resist chip 8 covers a region necessary for the LED chip 5 to be mounted on the first conductive pattern 3 and fixed by die bonding.
The upper surface of the chip 5 and the second conductive patterns 4 corresponding to these are electrically connected by bonding wires 6, and further, current limiting resistors 7 are arranged at predetermined intervals along the side edges of the printed board 2. Set up a certain number of LEDs
It was constructed by connecting the chip 5 to one current limiting resistor 7.

The second conductive pattern 4 for connection is arranged side by side with respect to the first conductive pattern 3 in a direction perpendicular to the longitudinal direction because of the warping of the printed circuit board 2. This is to prevent disconnection of the wire 6.

In the LED array 1 thus constructed, each LED chip 5 is caused to emit light by energizing each LED chip 5 through the current limiting resistor 7, and thus the line-shaped light source is generated. I was getting it.

[0005]

However, in the conventional LED array 1 having such a structure, the resist 8 covering the portions other than the areas such as the conductive patterns 3 and 4 on the surface of the printed board 2 has a high reflection efficiency. Since it was a bad black resist, gold plating was applied to the surfaces of the first conductive pattern 3 and the second conductive pattern 4 in order to increase the irradiation efficiency of the light emitted from each LED chip 5 to the original surface. By forming their areas relatively large, each LED
The reflection efficiency of the peripheral portion of the chip 5 was increased. Therefore,
Since the portions of the first conductive pattern 3 and the second conductive pattern 4 are large, the width of the printed circuit board 2 becomes relatively wide. For example, when the printed circuit board 2 is incorporated in an electronic copying machine, an LED printer, a facsimile machine, or the like, There is a problem that the installation space becomes large and these various devices become large in size. In addition, the second conductive pattern 4 for connection
However, since they are arranged side by side in the direction perpendicular to the longitudinal direction with respect to the first conductive pattern 3, the width of the printed circuit board 2 becomes wider, and the above-mentioned various devices become larger. There was a problem. Further, there is a problem that the cost is increased because the area to be plated with gold is relatively large.

In view of the above points, the present invention has an LED array in which the width of the printed circuit board of the LED array can be narrowed, the equipment in which the LED array is to be incorporated can be configured in a small size, and the cost can be reduced. Is intended to provide.

[0007]

According to the present invention, there is provided a first conductive pattern for mounting a plurality of LED chips arranged on a long printed circuit board in the longitudinal direction thereof. , Forming a plurality of connection second conductive patterns arranged along the longitudinal direction adjacent to each first conductive pattern, and applying a resist to the surface excluding the first and second conductive patterns. Apply and LE on the first conductive pattern
In an LED array in which a D chip is placed and fixed by die bonding, and the upper surface of each LED chip and the second conductive patterns corresponding to these are connected by bonding wires, the resist is white. This is achieved by an LED array characterized by being a resist.

[0008]

According to the above construction, since the surface of the printed circuit board is covered with the white resist and the reflectance thereof is relatively high, the light from the LED chip can be efficiently reflected by the surface of the white resist. The size of the first conductive pattern may be small enough to mount the LED chip, and the size of the second conductive pattern may be small. Therefore, since the width of the printed circuit board can be reduced, the LED
The array has a small installation space, resulting in LE
The device in which the D array is to be incorporated can be made compact. Further, the amount of gold plating on the first conductive pattern and the second conductive pattern can be small, and the cost can be reduced.

Preferably, if the second conductive pattern is arranged side by side with respect to the first conductive pattern in a direction along the longitudinal direction of the printed circuit board, the width of the printed circuit board can be further narrowed. As a result, the device into which the LED array is to be incorporated can be made more compact.

Further, preferably, if the LED and the bonding wire are covered with resin by potting, the disconnection of the bonding wire can be prevented, and the light collecting property is improved by the lens effect of the potting resin.

Further, preferably, if all of the LED and the bonding wire are uniformly covered with resin, the disconnection of the bonding wire can be prevented and the light collecting property is improved by the lens effect of the resin. There is also an advantage that uneven illumination is eliminated as compared with the case of potted resin.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 shows an embodiment of an LED array according to the present invention. This LED array 10
Is a first conductive pattern 12 on which a plurality of LED chips arranged along the longitudinal direction of the long printed circuit board 11 are to be mounted, and adjacent to each first conductive pattern 12. And a second conductive pattern 13 for connection, which is arranged along the longitudinal direction, and forms the first conductive pattern 12
The LED chip 14 is placed on the LED chip 14 and fixed by die bonding, and the upper surface of each LED chip 14 and the second conductive patterns 13 corresponding to these are electrically connected by a bonding wire 15. Further, the current limiting resistors 16 are arranged at predetermined intervals along the side edge of the printed circuit board 11, and a predetermined number of LED chips 14 are connected to one current limiting resistor 16.

The above-mentioned structure is the conventional LED shown in FIG.
LED having the same structure as the array 1 but according to the present invention
In the array 10, the white resist 1 is formed on the surface of the printed circuit board 11 except for the conductive patterns 12 and 13.
8 is applied, and the second conductive pattern 13 for connection is arranged adjacent to the first conductive pattern 12 for mounting the LED chip 14 in the longitudinal direction of the printed circuit board 11. Has been done. In this case, each LE
The D chip 14 and the bonding wire 15 are completely surrounded and protected by a transparent resin 17 formed by potting.

The LED array 10 according to the present invention is configured as described above, and each L is connected via the current limiting resistor 16.
By energizing the ED chip 14, each LED chip 14 is caused to emit light, which is collected by the transparent resin 17 and emitted to the outside, and a part of the light is reflected by the white resist 18, thus, the line Light source is available. At this time, the printed circuit board 11
Since the reflectance of the white resist 18 covering the surface of the LED chip is relatively high, the light emitted from the LED chip 14 can be efficiently reflected by the surface of the white resist, so that the first conductive pattern 12 mounts the LED chip 14 thereon. The second conductive pattern 13 may be small in size as long as it can be placed. Therefore, the width of the printed circuit board 11 can be small, and L
Since the width of the entire ED may be narrow, the installation space is small, and as a result, the device in which the LED array 10 is to be installed can be configured in a small size. Further, the amount of gold used for gold plating on the conductive patterns 12 and 13 is reduced, and the cost can be reduced. Further, since the second conductive pattern 13 is disposed adjacent to the first conductive pattern 12 in the longitudinal direction, the width of the printed circuit board 11 can be further reduced, and therefore the LED array 10 is incorporated. The device to be used can be further miniaturized. Furthermore, since each LED chip 14 is covered with the transparent resin 17, the bonding wire 15 can be protected, and the strength of the printed circuit board 11 against bending, warping, etc. is increased, and as a result, the bonding wire 15 is not broken. It can be surely prevented. Further, the lens effect of the transparent resin 17, that is, the light-collecting action also improves the light-collecting property.

FIG. 3 shows another embodiment of the LED array according to the present invention, in this case the LED array 20.
Is each LED chip 14 and bonding wire 15
However, the LED chips 14 and the bonding wires 15 are not integrally covered with the individually potted transparent resin, but are integrally covered with one transparent resin 21 uniformly formed along the longitudinal direction. The LED array 10 has the same configuration as that of the LED array 10 of FIG.

In this embodiment, each LED chip 1
Since 4 is covered with the integral transparent resin 21 extending in the longitudinal direction, it is possible to obtain a linear light source with no illumination unevenness. Further, in this case, since the second conductive pattern 13 is arranged adjacent to the first conductive pattern 12 in the longitudinal direction, the first and second conductive patterns are provided as in the conventional example. Compared with the case where the patterns are arranged in the direction orthogonal to the longitudinal direction, the transparent resin 2 that covers them is provided.
The quantity of 1 is also small, and the manufacturing cost is further reduced.

[0017]

As described above, LE according to the present invention is used.
According to the D array, the width of the printed circuit board of the LED array can be narrowed, the device in which the LED array is to be incorporated can be configured in a small size, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an embodiment of an LED array according to the present invention.

2 is a side view of the LED array of FIG. 1. FIG.

FIG. 3 shows another embodiment of the LED array according to the present invention, (A) is a schematic plan view thereof, and (B) is a side view thereof.

FIG. 4 is a schematic plan view of an example of a conventional LED array.

[Explanation of symbols]

 10 LED Array 11 Printed Circuit Board 12 First Conductive Pattern 13 Second Conductive Pattern 14 LED Chip 15 Bonding Wire 16 Current Limiting Resistor 17 Transparent Resin 18 White Resist 20 LED Array 21 Transparent Resin

Claims (4)

[Claims] 1. A first printed circuit board for mounting a plurality of LED chips arranged on a long printed circuit board along the longitudinal direction thereof, and adjacent to each of the first conductive patterns in the longitudinal direction. A plurality of second conductive patterns for connection arranged along with is formed, a resist is applied to the surface excluding the first and second conductive patterns, and an LED chip is mounted on the first conductive pattern. In an LED array configured to be placed and fixed by die bonding, and a bonding wire connects between the upper surface of each LED chip and the second conductive pattern corresponding to each of them.
LE wherein the resist is a white resist
D array. 2. The LED array according to claim 1, wherein the second conductive pattern is arranged side by side with respect to the first conductive pattern in a direction along the longitudinal direction of the printed circuit board. .. 3. The LED array according to claim 1, wherein the LED and the bonding wire are covered with resin by potting. 4. The LED and the bonding wire are all uniformly covered with resin.
The LED array according to item 2.