JPH10288966A - Led display unit and its driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize the LED display unit which can be made thin on the whole and have the optical axes of respective LED elements easily aligned with one another and hardly generates display unevenness and is excellent in visibility from the right and left. SOLUTION: This LED display unit is equipped with a substrate 16 which has a wiring pattern 42 and recessed parts 18 formed on its surface, metallic reflecting members 38 which are arranged on the internal wall surfaces of the recessed parts 18 and connected to the wiring pattern 42, an LED modules 22 having LED chips 20a and 20b which each have one end connected to a reflecting member 38 and the other end connected to the wiring pattern 42 through a bonding wire 40, and a transparent cover member 26 which have semielliptic spherical lens cap parts 24 formed. So that the array direction of the LED chips 20a and 20b in the recessed parts 18 matches the major- diameter side center axis (X) of the elliptic opening part of the lens cap part, the cover member 26 and LED module 22 are positioned, resin 28 is charged inside, and the LED elements 14 are formed between the respective lens parts 24 and recessed parts 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED display, and more particularly to an LED display having a structure in which a plurality of LED elements are arranged on a display surface and integrated.

[0002]

2. Description of the Related Art As a conventional LED display, for example, as shown in FIG. 11, each terminal 72 of a plurality of LED elements 70 is inserted into a through hole of a substrate 74 having a predetermined wiring pattern on the back surface. Some are fixed to the back surface of the substrate 74 via the solder 76. The LED display 78 is housed in a case 82 having eaves 80, for example, and is attached to a wall surface to be used as one element constituting a collective display panel such as a large outdoor display. The above substrate 74
Is filled with a resin material 84 for waterproofing. Further, a rear end surface 86 of the case 82 forms an appropriate inclined surface, and a positioning projection 88 is formed. For this reason,
When the rear end face 86 of this case is brought into contact with a vertical wall surface, the optical axis of each LED element 70 is slightly downward, so that a display suitable for looking up outdoors from below can be configured.

As shown in FIG. 12, the above-mentioned LED element 70 has a so-called hat-shaped envelope 90, and an LED element 70 is provided on the bottom surface of a concave portion 92 formed at the tip of one terminal 72a.
One end of the chip 94 is connected and the LED chip 94
Is connected to the tip of the other terminal 72b via a bonding wire (gold wire) 96. The front ends of the terminals 72a and 72b are molded with epoxy resin. In addition, a lens portion 98 for condensing light is integrally formed at a distal end portion of the envelope 90. The concave portion 92 has a funnel shape whose diameter increases from the bottom surface to the opening, and the wall surface forms a reflecting mirror.

[0004]

SUMMARY OF THE INVENTION A conventional LED display 78
In the above, a plurality of individually independent LEDs as described above
Since the elements 70 are assembled and the respective terminals 72 are inserted and mounted on the substrate 74, the overall thickness is inevitably increased by the amount of the terminals 72, which is a factor that hinders the thinning of outdoor displays and the like. Was. When soldering the terminal 72 of each LED element 70 by inserting the terminal 72 into the substrate,
The orientation of the lens portion 98 of each LED element 70 is likely to vary due to the inclination, warpage, or bending of the LED element 70, and it has been difficult to align the optical axes of the LED elements 70 in a certain direction. Moreover, each LE
The D element 70 was filled with molten resin in a hat-shaped resin envelope 90, and a terminal 72a having a concave portion 92 also serving as a reflecting mirror at a tip portion and the other terminal 72b were inserted into the hat. After that, since it is formed by curing the resin, it has been difficult to maintain high positional accuracy between the reflecting mirror (recess 92) and the lens 98. Therefore, even if each LE
Even if the lens portions 98 of the D elements 70 are aligned in a certain direction, the optical axes of the individual LED elements 70 are not aligned. There is a problem that brightness unevenness occurs and high display quality cannot be realized. Moreover,
The lens part 98 of each LED element 70 is substantially hemispherical,
Since it is desired to provide only one chip 94, there is a problem that visibility from the left and right directions is poor, irrespective of display properties in the front direction.

The present invention has been devised to solve such a conventional problem, and it is possible to reduce the thickness as a whole and easily align the optical axes of the LED elements. Therefore, it is an object to realize an LED display in which display unevenness hardly occurs and visibility from the left and right is good.

[0006]

In order to achieve the above object, an LED display according to the present invention comprises a substrate having a predetermined wiring pattern formed on a surface thereof, a plurality of recesses formed on the surface of the substrate, A plurality of metal reflecting members arranged on the inner wall surface of each recess and connected to the wiring pattern, a pair of LED chips arranged in each recess and having one end connected to the reflecting member, and the other end of each LED chip and An LED module having a bonding wire for connecting to a wiring pattern; and a cover member made of a light-transmitting material having a plurality of substantially semi-elliptical spherical lens cap portions formed thereon. Each concave portion of the module is covered, and the direction of the arrangement of the LED chips in each concave portion and the direction of the central axis on the major diameter side of the substantially elliptical opening of each lens cap portion are substantially the same. As to the cover member and the LED
The module is positioned, and the inner surface of the cover member and L
An LED element is formed between each lens cap portion and the concave portion by filling a resin material with the surface of the ED module.

This LED display is manufactured, for example, by the following steps. First, a predetermined wiring pattern is formed in advance on the surface of the substrate, a plurality of metal reflection patterns connected to the wiring pattern are formed, and a drawing process is performed on the reflection pattern forming portion.
A plurality of concave portions are formed on the surface of the substrate, and a plurality of reflective members are formed at the same time. Next, a pair of LED chips is arranged in each recess of the substrate, one end of each LED chip is connected to the reflection member, and the other end of each LED chip is connected to the wiring pattern via a bonding wire. To form an LED module. Next, a predetermined resin material is filled inside a cover member made of a translucent material in which a plurality of substantially semi-elliptical spherical lens cap portions are formed, and the LED chip arrangement surface of the LED module is turned downward. The cover member and the LED module are positioned so that the arrangement direction of the LED chips in the concave portion and the direction of the central axis on the long diameter side of the substantially elliptical opening of each lens cap portion substantially match. Finally, after the LED module is inserted into the cover member, the resin material is cured to form an LED element between each lens cap and the recess.

In this LED display, a plurality of LED elements are integrally formed from the beginning without assembling independent individual LED elements, and a terminal is provided for each LED element. Therefore, the overall shape can be reduced in thickness. In addition, each LED
As long as there is no terminal for each element, it is unlikely that the optical axes of each LED element will be irregular due to terminal failure,
Along with accurately setting the formation position of the lens cap portion in the cover member and the formation position of the concave portion in the substrate, as long as the positioning between the cover member and the substrate is accurately performed, the reflection member and the lens cap portion in the concave portion Can be aligned with high positional accuracy. At least, when a resin mold is applied to the distal end of the terminal, the lens cap portion needs to be aligned with the concave portion also serving as a reflecting mirror formed at the distal end of the terminal and the lens portion. The position accuracy between the mirror and the reflecting member can be dramatically improved. Further, each LED element has a pair of LEs.
Since a D chip is provided, and each LED chip is arranged along the longitudinal direction of the lens cap portion having a substantially semi-elliptical sphere, light distribution characteristics in the horizontal direction are improved, and visibility from the left and right can be improved. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. As shown in FIG.
Has a total of nine LED elements 14 formed integrally with the display surface 12 and arranged in a matrix.
Further, as shown in FIG.
An LED module 22 in which concave portions 18 are formed at nine locations on the surface of the LED chip 16 and LED chips 20 are disposed therein, and a cover member 26 having nine lens cap portions 24 for condensing light over the concave portions 18 And an epoxy resin 28 containing a light scattering material (glass beads) filled between the cover member 26 and the LED module 22 (FIG. 2 is a sectional view,
Although only three pieces 18 and three lens cap parts 24 are shown, actually nine pieces each are formed corresponding to the number of the LED elements 14). LED module 22 above
From the first external terminal 30, the second external terminal 32 and the third
The external terminal 34 is derived.

The substrate 16 of the LED module 22 is made of epoxy resin or the like, and the surface of the substrate 16 is subjected to drawing to form the concave portion 18 (as a result of the drawing, the backside of the substrate 16 is formed). Is formed with a convex portion 36 corresponding to the concave portion 18). FIG. 3 is an enlarged cross-sectional view showing the periphery of the concave portion 18. The concave portion 18 has a funnel shape whose diameter increases from the bottom side toward the opening side, and its inner surface is covered by a reflecting member 38. .

The reflection member 38 is made of a conductive metal such as copper, and its surface is plated with gold. A pair of LED chips 20a and 20b are arranged at a predetermined interval on the surface of the reflecting member 38.
One end of each 20b is electrically connected to the reflection member 38. The other end of each of the LED chips 20a and 20b is connected to a wiring pattern 42 provided in advance on the surface of the substrate 16 via a bonding wire 40 made of a gold wire or the like. Also,
Although not shown, each reflection member 38 is also connected to the wiring pattern 42.

A pair of LED chips 20a and 20b arranged in each recess 18 are selected to have the same luminescent color, and the LED module 22 as a whole emits red LED chips 20a and 20b. Are formed at four places, and five recesses 18 are provided with LED chips 20a and 20b for emitting green light. FIG. 4 is a circuit diagram showing a connection state of the LED chips 20a and 20b included in the LED module 22.
a and 20b are connected in parallel, and L for red emission is used.
The ED chips 20a and 20b are connected in series to form a group R, and the LED chips 20a and 20b for green light emission are also connected in series to form a group G. The other end is connected to the second external terminal 32, and the other end is connected to the third
Are commonly connected to an external terminal 34 of The wiring pattern 42 is drawn on the surface of the substrate 16 so as to realize such a circuit configuration. In the case of this LED module 22, all the LED chips 20a, 20
When b is turned on, a red display is realized, and when all the LED chips 20a and 20b belonging to the group G are turned on, a green display is realized. Further, all the LED chips 20 belonging to the groups R and G
By lighting a and 20b, a mixed color display of red and green can be realized.

The cover member 26 is, as shown in FIG.
It is formed in a shallow square shape, and on its bottom surface 26a, nine substantially semi-elliptical spherical lens cap portions 24 and four circular spacers 44 are integrally formed. This cover member 26
Is formed of a transparent weather-resistant acrylic resin or the like.
FIG. 6 is an AA sectional view of such a case member, and FIG. 7 is a BB sectional view. As shown in the figure, the opening 46 of the lens cap portion 24 has a central axis X that appears in the AA cross-sectional view thereof.
Has an elliptical shape longer than the central axis Y appearing in the BB cross-sectional view, and the LED chip in the concave portion 18 of the substrate 16
20a and 20b are arranged along the major axis X of the elliptical opening 46.

Next, a method of manufacturing the LED display 10 will be described. First, the substrate 16 with copper foil on one side
By selectively etching the surface, a required wiring pattern 42 is formed in advance, and nine circular reflection patterns connected to the wiring pattern 42 are formed. The surfaces of the wiring pattern 42 and the reflection pattern are plated with nickel, and further plated with gold. Next, a drawing process is performed on the reflection pattern forming portion to form the concave portion 18 and, at the same time, finish the reflection pattern on the reflection member 38. Next, a pair of LED chips 20a, 20b
Of the LED chips 20a, 20b
Is connected via the bonding wire 40 to the other end of the wiring pattern 42 and the wiring pattern 42 to realize the above circuit configuration.

After the LED module 22 is formed as described above, as shown in FIG. 8, the interior of the cover member 26 is filled with a molten epoxy resin 28, and the LED module 22 is turned upside down. 26 into the opening 26b. At this time, the distance between the LED chips 20a, 20b and the inner surface of the lens cap portion 24 is kept constant since the surface of the substrate 16 is in contact with the end surface of the spacer 44. In addition, through the through hole 48 formed in the substrate 16, excess resin
28 is released to the back side of the substrate 16.

Thereafter, the LED display 10 is completed by curing the resin 28, and the display surface 12 has the lens cap portion 24 of the cover member 26, the concave portion 18 of the substrate 16, the reflection member
38, nine LED elements 14 including a pair of LED chips 20a and 20b, bonding wires 40, and the like are provided (FIG. 1). Incidentally, in the case of the LED display 10 shown in FIG. 1, a green light emitting LED element is provided at the center and four corners.
14 are arranged, and L for red emission is provided in the remaining four places.
The ED element 14 is provided.

In the LED display 10, the substrate
The shape and size of the cover 16 and the shape and size of the opening 26b of the cover member are made uniform, and the concave portion 18 of the substrate 16 and the lens cap portion 24 of the cover member 26 are accurately formed at predetermined positions. For example, the LED module 22 and the cover member
When engaging with 26, the reflecting member 38 and the lens cap 24
And the positional accuracy of the position can be maintained at a high level.

As shown in FIG. 9, the LED display 10 is housed in a case 52 having an eaves 50 and then assembled in a dot matrix on a wall surface to be used as one element of an electric display panel. Is done. Front of case 52
Reference numeral 53 denotes a rectangular shape that matches the shape of the LED display 10, and the LED display 10 is housed in the opening of the front surface 53. The rear portion of the case 52 is connected to a cylindrical body portion 54 having a rear end surface 54a formed as an inclined surface. Also,
A projection 56 for positioning is formed on the rear end face 54a. Further, from the rear end face 54a, a power supply connection cord 58 connected to a power supply for lighting the LED element 14 is led out.

When the projections 56 are inserted into the vertically recessed engaging recesses on the wall (not shown) and the rear end surface 54a of the body 54 contacts the wall, each LED element 14 of the LED display 10 is ,
The optical axis is inclined slightly downward. As a result, when the display is looked up from below in the field, display with sufficient brightness can be realized. Further, the lens portion at the tip of each LED element 14 is constituted by a lens cap portion 24 having a substantially semi-elliptical sphere extending in the lateral direction, and a pair of LED chips 20 is provided in each LED element 14.
Since a and 20b are arranged side by side in the horizontal direction, the visibility in the left and right horizontal directions is also good.

Since the body 54 of the case 52 is formed in a cylindrical shape, as shown in FIG.
When the display devices 10 are assembled, a gap is formed between the body portions 54 of the cases 52, and a space for mounting an appropriate coupling member 60 behind the front surface portion 53 can be secured. If four or more LED displays 10 are connected in advance by the connecting member 60 and then attached to the wall, work efficiency can be improved as compared with a case where a single LED display 10 is individually attached. Can be planned.

[0021]

In the LED display according to the present invention, the independent individual LED elements are not assembled.
Since a plurality of LED elements are integrally formed from the beginning, it is not necessary to provide a terminal for each LED element, so that the overall shape can be reduced in thickness and the optical axis of each LED element is relatively easy. Can be aligned. In addition, since each LED element has a pair of LED chips arranged along the longitudinal direction of the substantially semi-elliptical spherical lens cap portion, it has excellent light distribution characteristics in the lateral direction and enhances visibility from the left and right. be able to.

[Brief description of the drawings]

FIG. 1 is a front view showing a display surface of an LED display according to the present invention.

FIG. 2 is a cross-sectional view of the LED display.

FIG. 3 is an enlarged sectional view showing the periphery of a concave portion of the LED display.

FIG. 4 is a circuit diagram showing a connection state of an LED chip.

FIG. 5 is a perspective view showing a cover member.

6 is a sectional view taken along line AA of FIG.

FIG. 7 is a sectional view taken along line BB of FIG. 5;

FIG. 8 is an exploded view showing an engagement process between the LED module and the cover member.

FIG. 9 is a side view showing a state where the LED display is housed in a case.

FIG. 10 is a rear view showing an example in which four cases are assembled.

FIG. 11 is a partial sectional view showing a conventional LED display.

FIG. 12 is a side view showing a conventional LED element.

[Explanation of symbols]

 10 LED display 14 LED element 16 Substrate 18 Recess 20a LED chip 20b LED chip 22 LED module 24 Lens cap 26 Cover member 28 Resin 38 Reflective member 40 Bonding wire 42 Wiring pattern 46 Oval opening X Central axis on major axis

Claims (2)

[Claims] 1. A substrate having a predetermined wiring pattern formed on a surface thereof, a plurality of recesses formed on the surface of the substrate, and a plurality of metal members arranged on the inner wall surface of each recess and connected to the wiring pattern. A reflecting member, a pair of LED chips disposed in each recess and having one end connected to the reflecting member,
An LED module having a bonding wire connecting the other end of the chip and the wiring pattern; and a cover member made of a light-transmitting material formed with a plurality of substantially semi-elliptical spherical lens cap portions. LED above by lens cap
Each recess of the module is covered and the LE in each recess
The cover member and the LED module are positioned so that the arrangement direction of the D chips and the direction of the central axis on the major diameter side of the substantially elliptical opening of each lens cap portion substantially coincide with each other, and the inner surface of the cover member and the LED module surface An LED display is characterized in that an LED element is formed between each of the lens cap portions and the concave portion by filling a resin material between the two. 2. A predetermined wiring pattern is formed on the surface of the substrate, a plurality of metal reflection patterns connected to the wiring pattern are formed, and a drawing process is performed on the reflection pattern forming portion. By forming a plurality of recesses on the surface of the substrate and simultaneously forming a plurality of reflection members, a pair of LED chips are arranged in each recess of the substrate, and one end of each LED chip is connected to the reflection member. And
The other end of each LED chip is connected to the wiring pattern via a bonding wire to form an LED module, and a cover member made of a translucent material having a plurality of substantially semi-elliptical spherical lens cap portions formed thereon. The inside is filled with a predetermined resin material, and the LED chip arrangement surface of the LED module is directed downward, and the arrangement direction of the LED chips in each recess and the major axis side central axis of the substantially elliptical opening of each lens cap portion. By positioning the cover member and the LED module so that the directions substantially coincide with each other, and curing the resin material after inserting the LED module into the cover member, the space between each lens cap portion and the concave portion is obtained. A method for manufacturing an LED display, comprising forming an LED element.