JPH11237850A - Led display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED display device with which luminance is more improved, the dispersion of luminance is reduced, an LED element is sufficiently protected as well, a production process is simplified and cost can be reduced. SOLUTION: Concerning an LED array 1, two pattern-wired printed wiring boards 30 and 31 in double layer structure are stuck, the display side substrate 31 is provided with an opening 27 and in that opening part 27, an LED element 32 is mounted. Then, the opening part 27 is sealed by filling the opening 27 with plastic resins 38 so as to cover the LED element 32 and a bonding wire 33 for mounting. Further, the opening 27 is filled with the plastic resins 38 so as to be projected in the shape of spherical surface up to a prescribed height on the surface of the display side substrate 31 and has a lens function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED display device in which LED elements suitable for being applied to a light source for sensors, a lighting device or a device for displaying a desired picture are two-dimensionally arranged.

[0002]

2. Description of the Related Art Display devices and lighting devices using LEDs are being widely used. In particular, a display device that sequentially displays desired characters and pictures on an LED array in which LED elements are two-dimensionally arranged is a simple advertising device.
Alternatively, it is widely used as a notification device for displaying various information.

FIGS. 8 to 10 show examples of a conventional LED array constituting such an apparatus. In the LED array 7 shown in FIG. 8, LED elements 72 are two-dimensionally arranged on a printed board 71, and the LED elements 72 are connected to circuits on the printed board 71 by bonding wires 73. Is protected by being coated with a resin coat 74. in this way,
By coating the surface of the LED element 72 with the resin coat 74, the LED element 72 can be protected from external chemical factors.

The LED array 8 shown in FIG. 9 also has a structure in which an LED element 72 is arranged on a printed circuit board 71 similarly to the LED array 7, but the LED element 72 including a bonding wire 73 is covered as a protection member. As
A hemispherical resin potting 75 is formed. By forming such resin potting 75, the LED element 7 can be effectively prevented from physical external factors.
2 and the bonding wire 73 can be protected.

In the LED array 9 shown in FIG. 10, the resin covering the LED elements 72 and the bonding wires 73 is formed in a predetermined shape (rectangular in FIG. 10).
By being formed in parallel with each other, the protection resin 76 protects the LED element 72 and the bonding wire 73 and also has an optical characteristic of appropriately emitting light from the LED element 72. It was done.

[0006]

However, since the LED array 7 as shown in FIG. 8 is not protected against a physical impact or the like, it is difficult to construct a display device or the like using the same. There is a problem that additional parts such as a protective case are required. Further, in such a configuration, there is a problem that the optical brightness cannot be improved by the resin, and the brightness of the light emitting unit depends on the brightness of the LED chip. Further, in the LED array 8 as shown in FIG. 9, since the height, spread, etc. of the resin potting 75 depend on the viscosity and amount of the resin, the height differs and varies depending on the production lot or potting. There is a problem that arises. Further, in the LED array 9 as shown in FIG. 10, since the protective resin 76 for each LED element 72 must be formed in the same shape and to have predetermined optical characteristics, a high precision There is also a problem that processing is required and the cost increases.

Accordingly, an object of the present invention is to provide an LED array on which a plurality of LED elements are mounted, which has higher luminance, has less variation in luminance, and protects the LED elements from both chemical and physical factors. Can be
An object of the present invention is to provide an LED display device whose manufacturing process is simple and cost-effective.

[0008]

In order to solve the above-mentioned problems, an LED display device according to the present invention comprises a first substrate on which pattern wiring is performed, and a plurality of first substrates arranged at predetermined positions on the first substrate. A plurality of LED elements and a substrate adhered to the first substrate, wherein a predetermined opening is provided at each of the locations corresponding to the LED elements arranged on the first substrate, A second substrate having a predetermined thickness for accommodating the LED element in the opening, and filling the opening of the second substrate attached to the first substrate; And a sealing member for sealing the LED element to be arranged.

[0009] The LED display device having such a configuration is the first type.
And a second substrate having an opening are adhered to form a concave portion, and an LED element is disposed here. Thereby, the light emitted from the LED element is reflected by the substrate on the bottom surface or the side surface and emitted to the front surface of the substrate. This also eliminates a physical impact or the like on the LED element from a lateral direction or a downward direction. Furthermore, the recess is filled with a member such as resin to seal the LED element,
This sealing member eliminates a chemical factor and a physical factor for the LED element. Further, since the sealing member is filled in the concave portion, the amount, height and surface shape thereof can be easily controlled, and a light emitting portion having desired optical characteristics can be formed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating an LED array 1 according to the first embodiment. As shown in the figure, the LED array 1 includes two printed wiring boards 30 having a two-layer structure, which are patterned and wired.
An opening 27 is provided in the display-side substrate 31, and an LED element 32 is mounted in the opening 27. The opening 27 is sealed with a plastic resin 38 so as to cover the LED element 32 and the bonding wire 33 for mounting. Further, the plastic resin 38 is filled in the opening 27 so that the surface of the display-side substrate 31 rises spherically to a predetermined height. In some applications, the opening 27 can be filled with a plastic resin 38 to a height substantially equal to the surface of the display-side substrate 31.

FIG. 2 is a sectional view of the LED mounting board 30 and the display-side board 31 for explaining the structure of the LED array 1 in more detail. As described above, the LED mounting board 30 is a printed circuit board having a two-layer structure in which a circuit pattern is formed on both sides by the copper foil 23 and the copper plating layer 22 and the insulating resist 21 is printed. In addition, LED
The mounting board 30 is provided with one or more buyer through holes 28. On the bonding surface of the LED mounting board 30 with the display side substrate 31, a bonding pad 29 for mounting the LED element 32 is formed on the same copper foil 23 and copper plating layer 22 as the circuit pattern and on the same. It is formed by a layer of the wire bonding plating layer 25.

Similarly to the LED mounting substrate 30, a pattern is formed on both sides of the display side substrate 31 and the insulating resist 2 is formed.
Reference numeral 1 denotes a printed circuit board having a two-layer structure on which printing is performed. The pattern formed on the display-side substrate 31 may be a normal circuit pattern. However, in the LED array 1 of the present embodiment, the surface of the display-side substrate 31 to be attached to the LED mounting substrate 30 is an LED element. A pattern for diffusing the generated heat is formed. That is, a pattern formed of a metal thin film having high thermal conductivity, having a relatively large width, and connected to a metal plating layer 24 on the side surface of the opening 27 described later is formed. Note that, in the present embodiment, this pattern is formed by the copper foil 23 and the copper plating layer 22, similarly to the LED mounting board 30.

At the position on the display side substrate 31 where the bonding pads 29 of the LED mounting substrate 30 are formed when they are adhered to the LED mounting substrate 30 as shown, an opening serving as a space for mounting an LED element is provided. 27 are provided. A glossy metal plating layer 24 is formed on the wall surface of the opening 27 to totally reflect the light from the LED element and dissipate the heat generated from the LED element to the heat diffusion of the display side substrate 31 described above. It plays a role in escaping into a pattern for use.

The LED mounting board 30 and the display-side board 31 are bonded to each other by press molding with an insulating adhesive sheet 26 interposed therebetween. The LED element 32 is mounted on the bonding pad 29 of the concave portion 27 formed by the bonded substrates 30 and 31, and its terminals are connected to the wire bonding plating layer 25 by wire bonding. By filling the resin 38, the LED array 1 as shown in FIG. 1 is formed.

Next, a method for manufacturing the LED mounting board 30 and the display-side board 31 of the LED array 1 will be specifically described with reference to FIG. FIG. 3 shows an LED array 1 including the LED mounting board 30 and the display-side board 31.
4 is a flowchart showing a manufacturing process of a substrate portion of FIG. First, the substrate is cut into a desired size (Step S1), and a hole is formed to form a buyer through hole 28 and an opening 27 in each substrate (Step S2). Next, pretreatment polishing for copper plating is performed (step S3), a copper foil 23 is formed by chemical copper plating (step S4), and a copper plating layer 22 is formed by electrolytic copper plating (step S3).
5). When the plating step is completed, pre-processing polishing for forming a circuit is performed (Step S6), and a circuit is formed (Step S7).

When the circuit formation is completed, pre-processing polishing for surface treatment is performed (step S8), and surface treatment is performed (step S9). At this time, specifically, NiAu plating treatment or NiPd
Au plating is performed, and the display side substrate 31 is N
Perform i-plating or NiPdAu plating. When the surface treatment is completed, the multi-layer press forming is performed with the processed insulating adhesive sheet 26 interposed between the LED mounting substrate 30 and the display side substrate 31 to form the substrate portion of the LED array 1 (step S1).
0). After the molding is completed, the outer shape is processed (step S1).
1) Cyan washing and pure water washing with ultrasonic waves are performed (step S12), and a final inspection is performed (step S1).
3) It is completed.

As described above, according to the LED array 1 of the first embodiment, since the metal plating layer 24 is formed on the side surface of the concave portion (opening) 27, the light from the LED element 32 is reflected. , Can be emitted to the front surface of the LED array 1. Therefore, the brightness of the light emitting section (opening 27) can be improved. Further, the LED element 32 and the bonding wire 33 in the concave portion 27 are sealed by pouring a plastic resin 38 into the concave portion 27, and the conventional resin potting illustrated with reference to FIG. Compared with the protective resin 76 illustrated with reference,
The LED element 32 and the bonding wire 33 can be protected by a simple method. Further, according to such a sealing method, the sealing can be stably performed with a uniform amount of resin, so that the variation in the brightness of each light emitting portion of the LED array 1 is reduced, and the uniformity of the light amount is improved. Na L
An ED array 1 can be provided.

Further, in this LED array 1,
The amount of the plastic resin 38 to be filled is increased so that the sealing material protrudes in a dome shape from the surface of the display-side substrate 31. As a result, the directional angle of the light emitted from the light emitting unit is widened, and a light emitting unit that can be appropriately viewed from anywhere is formed. Also, by arbitrarily changing the shape of the projection having the lens function, it is possible to form a light emitting portion having directivity in an arbitrary direction, or to improve the brightness by concentrating light in a predetermined direction. It becomes possible.

Further, the bonding surface of the display-side substrate 31 with the LED mounting substrate 30 is formed of a metal thin film having high thermal conductivity and a pattern for thermal diffusion is formed. Therefore, heat from the LED elements 32 can be quickly transmitted and diffused to the outside, and the temperature of the LED array 1 can be reduced. FIG. 4 shows the characteristics of the temperature of the LED array 1. As shown in FIG. 4, the LED array 1 of the present embodiment is always 5 times smaller than a conventional equivalent LED array regardless of the ambient temperature.
It can be seen that the temperature is lower by about ° C. In addition, since such cooling can be performed efficiently, a large amount of current can be applied to the LED element 32, and the luminance of the LED element 32 can be further increased.

Second Embodiment A second embodiment of the present invention will be described with reference to FIG.
The LED array 2 according to the second embodiment is different from the LED array 1 according to the first embodiment in that each light emitting unit (opening 2)
7) A display device equipped with a lens array in which a lens is formed for each.

In the LED array 2 according to the second embodiment, the recess 27 formed by the LED mounting board 30 and the display-side substrate 31 is filled with a plastic resin 38 so as not to protrude from the surface of the display-side substrate 31. I do. Then, a lens array 40 in which a glass or plastic lens is formed for each recess 27 is attached to the display side substrate 31 on the side opposite to the LED mounting substrate 30. The entire lens array 40 may be integrally formed of glass or plastic, or a hole may be formed in the substrate similarly to the LED mounting substrate 30 and the display-side substrate 31, and a glass or plastic lens may be formed here. It may have a configuration in which it is fitted.

According to the LED array 2 having such a configuration, it is possible to provide the LED array 2 that emits light that is more uniform and has no variation. And the lens array 4
By changing the lens shape of 0, it is possible to precisely realize a light emitting portion having various optical characteristics and directional characteristics,
An LED display device having desired characteristics can be provided.

Third Embodiment A third embodiment of the present invention will be described with reference to FIG.
As a third embodiment of the present invention, an LED chip having one light emitting unit will be described. FIG. 6 shows the LED chip 3
It is a figure showing the composition of (3a, 3b).

The basic configuration of this LED chip is the same as that of the LED array 1 of the first embodiment and the LE array of the second embodiment, except that each LED chip has one light emitting portion.
Same as D array 2. That is, the first substrate LED
In this configuration, a display-side substrate 31 having an opening is stuck on a mounting substrate 30, an LED element 32 and a bonding wire 33 are housed in a formed recess, and a plastic resin 38 is filled and sealed. Therefore, the LED chip 3 has the same effect as the LED arrays 1 and 2. The LED chip 3a is
The concave portion is filled with a plastic resin 38 until the height thereof is substantially the same as or slightly lower than the surface of the display-side substrate 31. It is formed by filling so as to protrude into a shape.

The LED chip 3 is manufactured by cutting and dividing the LED array 1 of the first embodiment described above for each light emitting portion. If the circuit patterns of the LED mounting board 30 and the display-side board 31 are changed to patterns for each light emitting unit, the LED array 1 manufactured by the exactly same configuration and method as shown in the first embodiment can be used. Only by cutting, a large number of such LED chips 3 can be manufactured. In other words, when manufacturing an LED chip that has higher brightness, less variation in brightness, can protect the device from both chemical and physical factors, and has a simple manufacturing process and can be manufactured at low cost. May be manufactured by dividing the LED array 1, and the LED chip 3 manufactured in this manner is also within the scope of the present invention.

Fourth Embodiment A fourth embodiment of the present invention will be described with reference to FIG.
The LED array 4 of the fourth embodiment is an LED array having the same configuration as the LED array 1 of the first embodiment, except that three LED elements 32a to 32c are provided in each recess 27.
Is arranged. If three bonding pads 29 are formed on the LED mounting board 30 corresponding to the opening 27, the LED array 4 having such a configuration can be easily configured.

With such a configuration, the brightness of each light emitting unit can be further increased, and a high-brightness LED array can be provided. Note that the number of LED elements 32 arranged in the opening 27 is not limited to three. It may be two or four or more, and any number may be arranged as long as space, heat generation, power consumption, and the like allow.

Fifth Embodiment A fifth embodiment of the present invention will be described. Although not shown, the LED array according to the fifth embodiment has substantially the same configuration as the LED array according to the fourth embodiment.
7, three LED elements 32a to 32c are arranged. However, in the LED array 1 of the fifth embodiment, these three LED elements 32a to 32a
32c has different wavelengths of light. That is, the configuration is such that three color LED elements of red (R), green (G) and blue (B) are arranged in one opening 27. According to the LED array having such a configuration, it is possible to configure a color LED display device capable of displaying a desired color for each pixel.

Modifications The present invention is not limited to the above-described first to fifth embodiments, and various modifications are possible. For example, the hole formed in the display-side substrate is a circular hole in any case, but may be a rectangular hole, and the shape is arbitrary. Also, the number of layers of the substrate can be arbitrarily changed depending on the application, for example, four layers, six layers, and the like. Also,
The LED element is mounted on the substrate using wire bonding, but the mounting means is not limited to this, and may be changed as appropriate. Further, the number of light emitting portions (openings) provided as an LED array may be arbitrarily changed according to the use of the display device.

[0030]

As described above, according to the present invention,
LED with higher brightness, less variation in brightness, protection of LED elements from both chemical and physical factors, simple manufacturing process and low cost
A display device can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an LED array according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an LED mounting board and a display-side board for describing the structure of the LED array shown in FIG. 1 in more detail.

3 is a flowchart showing a manufacturing process of a substrate portion of the LED array shown in FIG. 1 including the LED mounting substrate and the display side substrate shown in FIG. 2;

FIG. 4 is a diagram showing temperature characteristics of the LED array shown in FIG.

FIG. 5 is a diagram illustrating an LED array according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating an LED chip according to a third embodiment of the present invention.

FIG. 7 is a diagram illustrating an LED array according to a fourth embodiment of the present invention.

FIG. 8 is a diagram for explaining a conventional LED array.

FIG. 9 is a diagram for explaining another conventional LED array.

FIG. 10 is a diagram for explaining still another conventional LED array.

[Explanation of symbols]

1, 2 LED array 3 LED chip 21 Insulating resist 22 Copper plating layer 23 Copper foil 24 Metal plating layer 25 Wire bonding plating layer 26 Insulating adhesive sheet 27 Opening 28 Buyer through hole 29 bonding pad 30 LED mounting board 31 display substrate 32 LED element 33 bonding wire 40 lens array 7, 8, 9 LED array 71 printed board 72 LED element 73 bonding wire 74 resin coating 75: Resin potting 76: Protective resin

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Nakamura Takanori ▼ 2-17-7 Akitsucho, Higashimurayama-shi, Tokyo Inside Yoshimitsu Rika Co., Ltd. (72) Kenichi Okawa 2-17- Akitsucho, Higashimurayama-shi, Tokyo 7. Yoshimitsu Rika Co., Ltd.

Claims (1)

[Claims] A first substrate, a plurality of LED elements respectively arranged at predetermined positions on the first substrate, and a substrate adhered to the first substrate; A predetermined opening is provided at each of the locations corresponding to the LED elements arranged on the substrate, and a second substrate having a predetermined thickness such that the LED elements are accommodated in the openings; An LED display device comprising: a first substrate; and a sealing member that fills the opening of the second substrate attached to the second substrate and seals the LED element disposed in the opening.