JPS5915509Y2 - light emitting display device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a light emitting display device using light emitting diodes.

Conventional light emitting display devices of this type include a light emitting diode mounted on a substrate, wire bonding to wiring on the substrate,
placing and fixing a display board having through holes on the surface of the substrate;
At that time, the light emitting diode was positioned at the bottom of the through hole, and then the through hole was filled with an epoxy resin containing a scattering agent, and the whole was covered with a case.

According to this configuration, the contact surface between the epoxy resin filled in the through-hole and the substrate is limited to the bottom surface of the through-hole, and the area is small compared to the total amount of the epoxy resin filled.

As a result, stress due to the difference in thermal expansion of the constituent materials concentrates on the substrate and the portion where the light emitting diode is attached, causing the light emitting diode to come off the substrate or the wire to break.

Further, as described above, since the epoxy resin filled in the through hole is molded to envelop the light emitting diode and the wire, the amount of resin is large.

As a result, the resin expands and contracts significantly during use, which applies stress to the light emitting diode and the wire, causing the light emitting diode to come off or the wire to break as described above.

The purpose of this invention is to prevent stress from being applied to light emitting diodes and wires.

An embodiment of this invention will be described with reference to the drawings. Reference numeral 1 denotes a substrate made of epoxy resin, on the surface of which a required wiring pattern is formed.

Reference numeral 2 denotes a light emitting diode, which is attached to the surface of the substrate 1 by punching or other means, and a lead wire 3 led out from the light emitting diode and a wiring pattern on the substrate 1 are wire-bonded.

4 is a display board, for example made of thermoplastic (ABS, acrylic,
It is made of resin (Noryl or U polymer) and has a through hole 5 formed therein.

The through holes 5 are arranged and formed in accordance with the pattern of characters 9 and other shapes intended for the wheat culm.

6 is a transparent resin containing a scattering agent, and 7 is a case.

The configuration described so far is not particularly different from conventional devices of this type.

However, in this invention, in order to attach the display panel 4 to the substrate 1, the light-emitting diodes 2 and the wires 3 are first attached to the substrate 1 using a transparent epoxy resin 8 having a coefficient of linear expansion similar to the circumference of the substrate 1.
A thin coating is applied and these are solidified on the substrate 1.

Next, after attaching the display panel 4 to the substrate 1, a rubber-like silicone resin containing a scattering agent, which has poor pickling properties and has poor pickling properties, is placed in the through hole 5 as a resin 6 so as to overlap the surface of the resin 8. Fill it.

With this configuration, the light emitting diode 2 and the wire 3
Since the resin 8, that is, the epoxy resin that is in direct contact with the epoxy resin is merely a thin coating, the amount thereof is small compared to the conventional device, so this thermal expansion is extremely small.

Therefore, the stress caused by this expansion will not cause the light emitting diode 2 to separate from the substrate 1 or the wire 3 to be cut.

Even if thermal expansion occurs, the substrate 1 and the resin 8 will expand to the same extent because their linear expansion coefficients are the same as that of the substrate 1, so the stress on the light emitting diode 2 and wire 3 will be minimal. becomes.

On the other hand, when the resin 6 undergoes thermal expansion, since the resin 6 itself has poor adhesion to the resin 8, slippage only occurs at the interface between the two resins 8, 6, and even with the expansion of the resin 6, the light emitting diode 2 , no stress is applied to the wire 3.

It is convenient to interpose the resin 8 between the bottom surface of the display panel 4 and the front surface of the substrate 1 as shown in the figure, since the resin of the display panel 4 also prevents stress from being applied to the substrate 1.

As described above, according to this invention, the light emitting diodes and wires on the substrate are coated with a resin different from the resin containing the scattering agent, and then hardened on the substrate surface. This has the effect of avoiding the drawbacks of conventional devices, such as stress on the light emitting diode or wire, causing peeling or cutting.

[Brief explanation of the drawing]

The figure is a sectional view showing an embodiment of this invention. 1...Substrate, 2...Light emitting diode,
3...Wire, 4...Display board, 5...
...Through hole, 6...Resin containing scattering agent, 7.
...Case, 8...Resin for coating.

Claims (1)

[Scope of utility model registration request] A light emitting diode is attached to the surface of a substrate made of epoxy resin, and the light emitting diode and the wiring pattern on the substrate are connected with a lead wire, and the light emitting diode is attached to the surface of the substrate made of epoxy resin using an epoxy resin having a linear expansion coefficient similar to the circumference of the substrate. and a display board having a through hole, the display board being coated with a tingling wire, is attached to the surface of the substrate so that the light emitting diode and the wire are located at the bottom of the through hole, and the resin is in the through hole. A light emitting display device in which a silicone resin containing a scattering agent having poor adhesion is filled on top of the epoxy resin coating the light emitting diode and the wire.