JPH0362032B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of manufacturing a light emitting display that uses a light emitting element such as a light emitting diode (LED) to emit light from the front of a case. .

[Conventional technology]

A light emitting display 1 using a light emitting element such as a light emitting diode (LED) has the light emitting element part at the tip of the lead parts 2, 2 placed inside an opaque cylinder 3 made of synthetic resin or the like and having an open end and a rectangular cylinder in plan view. At least after curing, it is sealed in a transparent thermosetting synthetic resin 4, and one end of both the lead parts 2, 2 is exposed to the outside, and when an appropriate voltage is applied to the two lead parts 2, 2, The light emitted from the light emitting element portion passes through the transparent synthetic resin 4, but is reflected by the opaque cylinder, so that it exits only from the front of the case of the light emitting display 1 (see FIG. 4).

As shown in FIGS. 5 and 6, a conventional method for manufacturing such a light emitting display 1 is to use an adhesive tape 6 coated with a pressure-sensitive adhesive 5 on the top surface, and a flat surface with open upper and lower ends. A temporary bottom is completed by press-bonding the lower end surface of the cylinder 3, which is square in appearance, and sealing the lower end opening of the cylinder 3 with an adhesive tape 6, and then the upper end of the cylinder 3. While holding the tips of the lead parts 2, 2 together with the light emitting element in the opening, inject a transparent thermosetting synthetic resin 4 in the form of a fluid into the cylinder 3, and heat it for an appropriate period of time. After curing the adhesive tape 6
Alternatively, although not shown, an appropriate amount of transparent thermosetting synthetic resin 4 is injected into the cylinder 3 to which adhesive tape 6 has been temporarily attached, and the resin is cured by heating for an appropriate period of time. The adhesive tape 6
A bottom is formed at the lower end of the cylindrical body 3 by peeling off the cylindrical body 3, and the bottom is chosen to be free of foreign matter and air bubbles, and the tips of the lead parts 2 and 2 are exposed to the inside together with the light emitting element part. The transparent thermosetting synthetic resin 4 is again injected into the cylinder 3 in a fluid state.
It was completed by heating and curing.

[Problem that the invention seeks to solve]

However, there are burrs etc. on the lower end surface of the cylinder, and as the area of the lower end surface of the cylinder decreases as the light emitting display Y becomes smaller, the adhesion with the pressure-sensitive adhesive 5 in the adhesive tape 6 is reduced. tends to be incomplete,
The fluid resin 4 leaks from this incompletely bonded portion and adheres to the outer wall of the cylindrical body and hardens, resulting in the part having a defective appearance. On the other hand, if the wall thickness of the cylindrical body 3 is increased in order to increase the area of the lower end surface of the cylindrical body 3 while maintaining a constant light emitting area, the external shape of the light emitting display 1 will become large.

In addition, when the adhesive tape 6 is strongly pressed from the back side to ensure complete adhesion, the adhesive tape 6 at the lower end opening of the cylinder 3 is deformed into a curve, and after the synthetic resin 4 has hardened, its lower end surface, that is, the light emitting surface, becomes curved. This also causes defects. Moreover, this adhesive tape 6
The problem was that it was disposable and the manufacturing cost was high.

[Means and actions for solving problems]

Therefore, in the present invention, after sealing the lower end opening of the cylindrical body with a fluid thermosetting synthetic resin injected along the inner surface of the cylindrical body whose upper and lower ends are open,
A method for manufacturing a case with a bottom for a light emitting display by heating and curing, and then cutting the lower end of the cylindrical body and the lower end of the cured resin to an appropriate thickness, the method comprising: Taking advantage of the high viscosity and surface tension of fluid resin, when this resin is injected along the inner surface of the cylinder, the bottom opening of the cylinder is closed with resin, and the resin is heated and cured in that state. A bottom is made of transparent resin at the bottom opening of the cylinder. By cutting off the lower end of this cured resin and the lower end of the cylindrical body by an appropriate thickness, it is possible to form a light-emitting display with a flat light-emitting surface at that portion.

Furthermore, since impurities and foreign matter settle at the bottom during pouring and hardening of the fluid resin, these impurities can be removed during the cutting process.

〔Example〕

Next, an embodiment of the present invention will be described. As shown in FIG. 1, a cylindrical body 1 made of an opaque thermosetting synthetic resin and having a rectangular cylindrical shape in a plan view or the like is opened at the upper and lower ends.
0 are arranged at appropriate intervals, and each cylinder 10
The left and right outer surfaces of the cylinder body 10 are held between the chucks 11, 11, and the resin injector 12 is faced to the upper end opening of each cylinder body 10, from which a thermosetting synthetic resin is flowable and has translucency after curing. The resin 13 is caused to flow down along the inner wall surface of each cylindrical body 10 at room temperature.
By utilizing the high viscosity and high surface tension of the resin 13, the lower end opening of each cylindrical body 10 is closed with the fluid resin 13. In this state, the upper surface of the resin 13 has a downwardly convex curved shape, and the lower surface has an upwardly convex curved shape (see FIG. 1).

In this state, when heated next, each cylinder 1
The viscosity of the resin 13 in the resin 13 becomes slightly lower once, and its lower surface also becomes downwardly convexly curved, but the lower end opening of the cylinder remains closed and hardens as it is (see FIG. 2).

After this hardening is completed, an appropriate thickness is cut across the lower end of the cylinder 10 and the lower end of the resin 13 using a cutting tool (not shown) at the position indicated by the dashed line 14 in FIG. A case 15 is formed, and the cut surface is the light emitting display 1.
It becomes the front surface, that is, the light emitting surface.

On the other hand, a lead frame (not shown) is constructed by punching out a metal plate material and connecting a pair of cathode leads 16 and anode leads 17 constituting a light emitting diode at appropriate intervals, and the tips of each of the cathode leads 16 are By mounting a semiconductor chip on the part and performing wire bonding on the paired cathode lead 16 and anode lead 17,
The light emitting element section 18 is configured in advance.

Next, as shown in FIG.
Both lead portions 16, 1 are inserted from the upper end opening thereof into
7 and the light emitting element portion 18 are inserted, and a thermosetting synthetic resin 19 having the same fluidity as the resin 13 is filled into the case 15 and then heated and cured. As a result, the light emitting element section 18 is enclosed within the case 15.

Thereafter, while polishing the front surface, the lead frame is separated so that the cathode lead 16 and the anode lead 17 are separated.
As shown in the figure, the light emitting display 1 is completed which is held with one end of both lead parts 16 and 17 protruding to the outside.

[Efficacy of invention]

In this way, in the present invention, when fluid resin is injected along the inner wall of the cylinder whose upper and lower ends are open, the lower end opening of the cylinder is closed due to the high viscosity of the resin. By taking advantage of this fact, after heating and curing, the lower end of the resin and the lower end of the cylinder can be cut off to form a light-emitting surface, eliminating the need to use adhesive tape as in the past. The cost can be reduced by the amount of adhesive tape.

After the transparent resin is cured when forming the bottom of the case, the lower end is cut to an appropriate thickness to expose the transparent resin, so the area that will become the light emitting surface of the light emitting display is flat. In addition, foreign matter and impurities that get mixed in when resin is injected tend to accumulate at the bottom, but these can be removed at the same time during the cutting process, which also makes it possible to eliminate defective products. be effective.

Even if the wall thickness of the side plate portion of the case is reduced, the lower end opening can be sealed using the high viscosity of the fluid resin, so the shape of the light emitting display can be reduced in size.

Although this example shows a case in which the flowable synthetic resin is injected into two parts, in another example, the light emitting element part at the lower end of the lead is inserted in advance from above into a cylinder whose upper and lower ends are open. Then, when a fluid thermosetting synthetic resin is injected all at once along the inner surface of the cylinder until it reaches the top surface of the cylinder, the resin has high viscosity and surface tension, so the fluid resin flows into the cylinder. It stays inside the cylinder without leaking from the bottom end.

By heating and curing in this state and then cutting the lower end of the cylindrical body and the lower end of the cured resin to an appropriate thickness, the same effect as in the above embodiment is produced, and
The injection work of fluid synthetic resin can be completed in one go.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing a state in which fluid resin is injected into the cylinder along its inner wall surface, Fig. 2 is a side sectional view showing the state of heating and hardening, and Fig. 3 is a side sectional view showing the lead portion inside the cylinder. FIG. 4 is a perspective view of the finished product, FIG. 5 is a perspective view of a conventional example, and FIG. 6 is a sectional view taken along the - line of FIG. 5. . 1... Light emitting indicator, 2, 2... Lead section, 3...
... Cylinder, 4 ... Thermosetting resin, 5 ... Pressure sensitive adhesive, 6 ... Adhesive tape, 10 ... Cylinder, 11, 1
1...chuck, 12...syringe, 13, 19...
...Thermosetting resin, 15...Case, 16...Cathode lead, 17...Anode lead, 18...
Light emitting element part.

Claims (1)

[Claims] 1. After sealing the lower end opening of the cylinder with a fluid thermosetting synthetic resin injected into the inner surface of the cylinder whose upper and lower ends are opened, the resin is heated and cured, and then the lower end of the cylinder and the A method for manufacturing a light emitting display, comprising cutting a lower end of a cured resin to an appropriate thickness.