JP2003031854A - Seven segment led figure indicating unit and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a figure indicating unit is reduced in quality and reliability due that various troubles such as damage to an LED chip, entrainment of air bubbles and the like occur when a lamp house is built in, where the lamp house is required to be built in a conventional method of manufacturing this kind of a figure indicating units. SOLUTION: A combination of LED chips 2 forming seven segments is arranged on a board 1, a transparent part 3 of transparent epoxy resin is formed on the board 1 through a primary transfer molding process so as to cover the segments, light shading grooves 3a each having an optional width are provided to the transparent part 3 so as to isolate the segments from each other, segment demarcating parts 4 of opaque epoxy resin are each provided in the light shading grooves 3a through a secondary transfer molding process, and then a seven segment LED figure indicating unit is capable of indicating the number of optional-numbered figures by optionally dividing the transparent part 3 in this manufacturing method. A lamp house assembly operation damaging an LED chip can be dispersed with, so that the problem can be solved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is referred to as a 7-segment numeral display, and seven substantially rectangular segments are combined into an eight-character shape to form a one-digit display. A number from 0 to 9 can be displayed by turning on a predetermined object, and more specifically, it relates to a number display device using an LED lamp as a light source of the segment. In addition to the above seven segments, there is also a segment in which a substantially circular segment representing a decimal point is added, but in the present invention, the segment is also referred to as a 7-segment numeral display.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show an example of a method of manufacturing a conventional 7-segment LED numeral display device of this kind (hereinafter, abbreviated as a numeral display device). First, the numerals shown in FIG. In the manufacturing method of the display device 90, one digit of LED
Chip 92, ie 7 or 8 LED chips 9
A lamp house 93 having a hollow segment 93a is attached to a predetermined position by adhesion or the like (see FIG. 7 (A)) on a substrate 91 on which 2 is mounted as a predetermined position, and
A thermosetting resin 94 such as a transparent epoxy resin is injected into the segment 93a as shown in FIG. 7 (B) and cured to complete a numeral display 90 as shown in FIG. 7 (C). It

Further, in the method of manufacturing the numeral display device 80 shown in FIG. 8, first, as shown in FIG. 8A, the lamp house 83 is pasted on the tape 85 with a predetermined space facing down, An appropriate amount of thermosetting resin 84 such as liquid transparent epoxy resin is filled. Then, as shown in FIG. 8B, the lead frame 81 holding a predetermined number of the LED chips 82 at a predetermined position when the resin 84 is in a liquid state is dipped. Then, when the resin 84 is hardened, the lead frame 81 is shaped and cut as shown in FIG.
As shown in (D), the numerical display 80 can be obtained. In the manufacturing method shown in FIG. 8, the lead frame 81 may be replaced with a substrate having a shape substantially similar to that shown in FIG.

[0004]

However, in the above-mentioned conventional manufacturing method shown in FIG. 7, in the step of adhering the lamp house 93 to the substrate 91, the LED chip 92 which is still in an exposed state, Alternatively, although not shown, there is a high possibility that the lamp house 93 will be brought into contact with and damaged by the bonding wire for wiring that is performed on the LED chip 92, and therefore careful work is required and the production efficiency is reduced. Giving rise to points.

Further, a resin 94 is placed in the segment 93a.
When injecting, the injection amount is likely to be excessive or insufficient, the directional characteristics at the time of lighting may be varied, or the display performance may be deteriorated such as uneven brightness, and the appearance may be deteriorated. There is a problem that the value is reduced.

Further, in the manufacturing method shown in FIG. 8, the resin 84 is injected from the rear surface in a state where the front surface of the lamp house 83 is covered with the tape 85 so that the front surface is flush with the tape 85. It does not appear on the display surface side. However, since the lead frame 81 is pushed into the already injected resin 84, the resin 84
It is easy for air bubbles to be trapped in the air bubbles, which can be seen from the display surface and impair the display quality.
When located near the chip 82, the LED chip 82
However, there is a problem in that the deterioration of the device is promoted and the reliability is lowered.

[0007]

As a concrete means for solving the above-mentioned conventional problems, the present invention provides at least a segment portion on a substrate on which a plurality of combinations of LED chips constituting 7 segments are arranged. A transparent epoxy resin to a predetermined thickness to form a light-transmitting portion so that each of the segments can be independently formed in the light-transmitting portion. A 7-segment L characterized in that a light-shielding groove having a width is formed, and a secondary transfer molding with an opaque epoxy resin is performed in the light-shielding groove to form a segment partition portion, which is thereafter divided into an arbitrary number of digits.
The problem is solved by providing a method of manufacturing an ED numeral display and a 7-segment LED numeral display manufactured by this manufacturing method.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail based on the embodiments shown in the drawings. 1 to 4 show a method of manufacturing a 7-segment LED numeric display 10 (hereinafter abbreviated as numeric display 10) according to the present invention in the order of steps. First, as shown in FIG. LE on the printed wiring board 1 on which terminals, terminals, etc. are formed in a predetermined shape.
Seven or eight D chips 2 (in the case of having a decimal point) are mounted, and if necessary, wiring with a gold wire or the like is performed. At this time, according to the present invention, the printed wiring board 1 is provided with wirings corresponding to the plurality of numeral displays 10, and basically, the numeral display 10 is obtained by cutting every digit in the final step.

FIG. 2 shows an LED numeral display 1 according to the present invention.
2 shows a primary transfer molding step in the manufacturing method of No. 0. In this primary transfer molding step, the transparent portion 3 is formed of transparent epoxy resin so as to cover the LED chip 2. In forming the light-transmitting portion 3, the light-transmitting portion 3 is formed at least in a portion to be the segment 11 (see FIG. 5) as the numeral display 10, that is, in the vicinity of the LED chip 2. Be present.

The transparent epoxy resin does not necessarily have to be colorless and transparent. For example, if the LED chip 2 emits red light, it may have the same color as the emission color such as red transparent. good. Further, for example, a suitable amount of white powder may be mixed to appropriately diffuse the light from the LED chip 2 so that the entire segment 11 shines as a uniform brightness.

FIG. 3 also shows a dicing step in the manufacturing method according to the present invention. In the dicing step, the numeral display is provided on the translucent portion 3 described above by, for example, a semiconductor cutting cutter. Light-shielding groove 3a so that each of the 10 segments 11 is made independent
To form.

When forming the light shielding groove 3a,
The opaque epoxy resin that is injected in the subsequent step is set as an appropriate groove width that can ensure necessary and sufficient light-shielding properties, and the wiring laid on the printed wiring board 1 by the light-shielding groove 3a, Alternatively, the depth is set as an appropriate groove depth that does not damage mounted components.

FIG. 4 also shows a secondary transfer molding step in the manufacturing method according to the present invention.
A segment partition 4 is formed by injecting an opaque epoxy resin, which is made by mixing a pigment and the like into an epoxy resin, into the light-shielding groove 3a formed in the previous step to form one segment 11
When each segment is turned on, the other segments 11 will not appear to be turned on.
This is a process performed for the purpose of shielding the space.

By doing so, each segment 11 is surrounded on four sides by the segment partition portion 4 formed of the opaque resin, so that when one LED chip 2 is turned on, that LED chip 2 is turned on. Only the segment to which it belongs will be illuminated brightly, and the target number will be clearly displayed. In the secondary transfer molding step, the injection of the opaque epoxy resin is performed by using a mold having the same thickness as that when the transparent portion 3 is formed, and the segment partition portion 4 is projected on the transparent portion 3. Be careful not to cause this.

Here, if the color of the pigment or the like mixed with the epoxy resin is a dark color system such as black, which has a high light shielding effect, the groove width of the light shielding groove 3a can be set to be narrow. On the other hand, the segment partitioning portion 4 formed by being injected into the light shielding groove 3a hardly reflects light, and therefore, it is necessary to adopt a measure such as adopting a large amount of light for the LED chip 2. Further, when the color is dark such as black, it is easy to design the high contrast with the light transmitting portion 3.

If a light-colored system such as white, which has a high reflected light with respect to the light, the segment partitioning portion 4 reflects the light toward the inside of the segment 11 and the segment 1
Although it is possible to lighten the whole 1, on the other hand, the segment partitioning portion 4 tends to be inferior in the light shielding effect on the other hand, and therefore, the width of the light shielding groove 3a is widened as compared with the above black case. Is required. Further, in terms of design, the contrast with the transparent portion 3 tends to be low. Therefore, whether the segment partition section 4 is a dark color system or a light color system may be selected depending on the brightness at the time of lighting, the required design, or the like.

The printed wiring board 1 on which the light transmitting portion 3 and the segment partition portion 4 are formed as described above is cut and individually divided as shown in FIG. 5, whereby the present invention is realized. The numerical display 10 is obtained. still,
If necessary, as shown in FIG. 6, it may be divided into a state in which two or more numbers are connected, and the multi-digit numeral display 20 of arbitrary digits may be used.

Next, the operation and effect of the numeral display device 10 of the present invention having the above structure will be described. First, the light-shielding groove 3a is formed in the light-transmitting portion 3, and the segment partitioning portion 4 is formed in the light-shielding groove 3a by the secondary transfer molding process. This is caused by the conventional manual potting mold. The occurrence of light unevenness on the segment surface due to insufficient or excessive injection amount is prevented. Further, at the same time, it is possible to improve the appearance as the translucent portion 3 and the segment partition portion 4 are always aligned on the same surface.

Further, since both the transparent portion 3 and the segment partition portion 4 can be formed by transfer molding,
No entrapment of bubbles during molding
It is possible to diffuse the light without any disturbance, and it is possible to improve the moisture resistance of the LED chip and improve the reliability.

Further, a light shielding groove 3a is formed in the light transmitting portion 3,
In the conventional method, the segment partitioning portion 4 corresponding to the lamp house is formed in the light-shielding groove 3a. In the conventional example, the LED chips and the like may be damaged when they are attached, so that careful attention is required. Eliminating the complicated lamp house installation process makes it possible to improve productivity.

[0021]

As described above, according to the present invention, 7
On a substrate on which a plurality of combinations of LED chips constituting a segment are arranged, a transparent transfer resin is formed to a predetermined thickness so as to cover at least the segment portion to form a transparent portion, and then the transparent portion is formed on the transparent portion. Forming a light-shielding groove having an appropriate groove width within the range of the thickness of the light-transmitting portion so that each of the segments is independent,
Damage to the LED chip is achieved by forming a segment partition by performing secondary transfer molding with an opaque epoxy resin in the light-shielding groove, and then forming a 7-segment LED numeral display that is divided by an arbitrary number of digits. It is extremely effective in improving productivity by eliminating the need to install the lamp house, which is a factor of, and also in improving the display quality by preventing air bubbles from being mixed into the encapsulating resin. It will play. In addition, the prevention of the inclusion of air bubbles also improves the moisture resistance of the LED chip and has an extremely excellent effect on the improvement of reliability.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a first step of a method for manufacturing a 7-segment LED numeral display device according to the present invention.

FIG. 2 is an explanatory view showing a second step of the method for manufacturing the 7-segment LED numeral display device according to the present invention.

FIG. 3 is an explanatory view showing a third step of the method of manufacturing the 7-segment LED numeral display device according to the present invention.

FIG. 4 is an explanatory view showing a fourth step of the method of manufacturing the 7-segment LED numeral display device according to the present invention.

FIG. 5 is a perspective view showing a 7-segment LED numeric display formed by the manufacturing method according to the present invention.

FIG. 6 is a perspective view showing another form of a 7-segment LED numeral display device similarly formed by the manufacturing method according to the present invention.

FIG. 7 is an explanatory diagram showing a manufacturing method in a conventional example.

FIG. 8 is an explanatory view showing another manufacturing method in the conventional example.

[Explanation of symbols]

1 ... Printed wiring board 2 ... LED chip 3 ... Translucent part 3a ... Shading groove 4 segment segment 10 …… 7-segment LED number display 11 …… Segment 20 ... Multi-digit 7-segment LED number display

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5C094 AA42 AA43 BA26 CA16 ED15                       GB01                 5F041 AA43 DA13 DA20 DA44 DA57                       DA92 DB05

Claims (2)

[Claims] 1. A light-transmitting portion is formed on a substrate on which a plurality of combinations of LED chips constituting 7 segments are arranged by performing a primary transfer molding with a transparent epoxy resin to a predetermined thickness so as to cover at least the segment portion, Then, a light-shielding groove having an appropriate groove width within the range of the thickness of the light-transmitting portion is formed in the light-transmitting portion so that each of the segments is independent, and a secondary transfer mold made of an opaque epoxy resin is formed in the light-shielding groove. A method for manufacturing a 7-segment LED numerical display, characterized in that a segment partition portion is formed by performing the step and then divided into an arbitrary number of digits. 2. A 7-segment LED numeric display manufactured by the manufacturing method according to claim 1.