JPH0792642B2 - Light emitting diode display - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a light emitting diode display device used for digital display, bar graph display, and various other displays.

(Prior Art) Generally, in a light emitting diode display device 1, as shown in FIG. 4, a light transmitting hole 3 which is a segment of a desired display pattern is formed on a display surface of a case 2 made of opaque plastic, and this hole is formed. 3 is filled with a translucent resin 4 of an appropriate color mixed with a light diffusing material, and a light emitting diode element 6 on a lead frame 5 mounted from the back of the case 2 is placed inside each translucent hole 3. The lead frame 5 is engaged with the formed small hole 7, and the lead frame 5 is fixed with the resin 11 filled in the back portion thereof.

In this case, since the small hole 7 is configured to be slightly larger than the light emitting diode element 6, the light emitted from the light emitting diode element 6 is emitted between the element 6 and the small hole 7 and between the inner leads of the lead frame 5. There was a case where the material leaked to the back of the lead frame 5 through the gap and entered into the segment that was not in the light emitting operation, resulting in an erroneous display.

Therefore, in order to prevent such erroneous display, a structure has been considered in which the back resin 11 of the lead frame 5 is made of black resin to prevent light leakage.

(Problems to be Solved by the Invention) As described above, the means for changing the back resin 11 to the black resin exhibits the initial function by properly filling the back resin 11 on the back surface of the lead frame 5 as shown in the drawing. If the amount of the translucent resin 4 to be initially filled is large and the resin 4 may go around the back of the lead frame 5, the light shielding effect becomes insufficient. Met.

In other words, the above-mentioned light-shielding means has a problem that a high resin injection accuracy of the light-transmissive resin is required for quality improvement and two resin injection steps are required, which lowers productivity.

An object of the present invention is to solve the problems found in the above conventional means by improving the light shielding means.

(Means for Solving Problems) In order to achieve the above object, in the present invention, a lead frame in which a light emitting diode element is incorporated is provided with a case where a light transmitting hole corresponding to the light emitting diode element is formed. While being mounted to the case from behind, the light absorbing material is closely fixed to the back surface of the lead frame, and the case is filled with a translucent resin for embedding the lead frame and the light absorbing material. A light emitting diode display device was constructed.

(Operation) According to the above configuration, an appropriate amount of the translucent resin in a molten state is injected into the translucent hole in the case and the lead frame mounting space,
Next, insert the lead frame into the injection resin from the back of the case so that the light emitting diode element fits into the small hole of each light-transmitting hole, and at the same time as or after inserting the lead frame, the light absorbing material is inserted from the back of the case. The assembly is completed by embedding it in a resin, attaching it to the back surface of the lead frame, and heating and curing the resin in the case.

The light emitting diode display device manufactured in this way is
Since the light absorbing material is attached to the back surface of the lead frame, light leakage between adjacent segments is surely prevented.

(Example) Below, the Example of this invention is described in full detail based on drawing.

FIG. 2 shows a light emitting diode digital display device 1 as an example of the light emitting diode display device. As shown in FIG. 1, a case 2 made of opaque plastic is provided with a group of light-transmitting holes 3 forming a segment of a known digital pattern. The hole 3 is filled with a transparent resin 4 of a desired color in which a light diffusing material is mixed.
On the lead frame 5 mounted from the back of the case 2,
A group of light emitting diode elements 6 is incorporated. And
These light emitting diode elements 6 are inserted and mounted in the small holes 7 formed in the inner depths of the respective light transmitting holes 4.
The back portion of the lead frame 5 is filled with a resin 4'of the same material as the resin 4 filled in the light transmitting hole 3, and a group of lead terminals 8 led out from the lead frame 5 is provided on the rear surface of the case so as to project.

In the above basic structure, in the present invention, the light absorbing material 9 made of a dark black plastic plate (for example, Bakelite plate) attached to the back surface of the lead frame 5 is further provided on the back resin 4 '.
It is a structure buried inside.

Next, a process of assembling the light emitting diode display device 1 will be described with reference to FIG.

First, the case 2 is turned over and the tape 10 is attached to the display surface.

Next, the molten translucent resin 4 is poured into the lead frame mounting space.

Next, the lead frame 5 incorporating the light emitting diode elements 6 is inserted into the injection resin 4 from the back of the case 2 and
Each light emitting diode element 6 is fitted into the small hole 7 of each segment.

Next, the light absorbing material 9 is inserted and embedded in the injection resin 4 and brought into close contact with the back surface of the lead frame 5.

After the resin 4 is cured, the tape 10 is peeled off.

Through the above steps, the light emitting diode display device 1 is completed.

(Other Example) The light absorbing material 9 may be adhered to the back surface of the lead frame 5 in advance, and may be embedded in the injection resin 4 together with the lead frame 5.

The light-absorbing material 9 may be implemented by a paper material or a sheet-shaped material such as a plastic sheet.
However, in this case, it is desirable that the light absorbing material 9 is bonded to the back surface of the lead frame 5 in advance as described above.

The light absorbing material 9 is formed in a block shape, and the back resin 4 '
It is also possible to embody it in a form in which a part of the light absorbing material 9 is exposed to the back of the case when it is buried inside.

As the display device 1 itself, digital display type, bar graph display type, dot display type, and other types of display patterns can be applied.

(Effect) As described above, according to the present invention, since the light absorbing material that is in close contact with the back surface of the lead frame is embedded in the resin filled in the back portion of the lead frame, the light is absorbed by the light absorbing material regardless of the injection amount of the resin. It is not blocked and does not reach the back side of the lead frame, and thus it is possible to reliably prevent light from leaking to the adjacent segment due to light sneaking into the filling resin on the back side of the lead frame. Further, by blocking the light at the lead frame portion, it is possible to reduce the light loss and increase the luminous intensity of each segment portion.

In addition, like a two-layer filling means of translucent resin and black resin,
Since the resin filling step is not required twice, the processing time can be reduced and the productivity is improved.

Further, unlike the two-layer filling means, it is not necessary to increase the precision of the injection amount of the translucent resin, so that the workability is improved and the efficiency is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a light emitting diode display device according to the present invention, FIG. 2 is an external perspective view showing an example of a light emitting diode digital display device, and FIG. 3 is a vertical sectional view showing one state of an assembly process. FIG. 4 is a vertical sectional view of a conventional example. 2 ... Case, 3 ... Translucent hole, 4 ... Translucent resin, 4 '... Back resin, 5 ... Lead frame, 6 ... Light emitting diode element, 7 ... Small hole, 9 ... Light absorber

Claims (1)

[Claims] 1. A lead frame in which a light emitting diode element is incorporated is attached to the case from behind a case in which a light transmitting hole corresponding to the light emitting diode element is formed, and a light absorbing material is provided on the back surface of the lead frame. And a light-transmitting resin for embedding the lead frame and the light-absorbing material in the case.