JP2000012214A - Manufacture of electroluminescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing for an inexpensive thing electroluminescent lamp suitable for a backlight of a liquid crystal display used for compact hand-held electronics, etc., and provided with a noise prevention function and an electromagnetic shield. SOLUTION: A transparent electrode 1b, a luminous layer 2, a reflective insulating layer 3, a backside electrode 4, a electrode pad 5 for the transparent electrode, and an overcoating layer 7 are formed on the backside of a transparent film 1a. A transparent third electrode 1c and an electrode pad 6 are formed on the front surface of the transparent film 1a. Then, an electrode sheet 10 in which leads 8a, 8b, 8c are connected on a heat sealing tape 9 is folded to sandwich the EL element, thus the respective leads 8a, 8b, 8c are contacted with the respective electrode pads 5, 6. After that, they are heated and pressured from both sides to connect the leads in a lump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electroluminescent lamp, and more particularly to a method for connecting leads of a thin electroluminescent lamp provided with noise prevention, electromagnetic shielding and the like suitable for a backlight of a liquid crystal display. .

[0002]

2. Description of the Related Art In recent years, portable telephones equipped with a liquid crystal display,
Various electronic devices such as HSs, pagers, digital watches, and portable personal computers have rapidly become widespread, and the demand for thin, surface-emitting electroluminescent lamps for backlighting liquid crystal displays has been increasing. When an AC high voltage is applied to cause the electroluminescent lamp to emit light,
Alternatively, noise may be generated due to electrostatic coupling between the electroluminescent lamp and the liquid crystal display unit. Further, noise generated from an inverter circuit for driving the electroluminescent lamp and the like may adversely affect the liquid crystal display unit and the electronic device via the electroluminescent lamp. For this reason, a three-electrode electroluminescent lamp provided with noise prevention, electromagnetic shielding and the like has been developed.

As shown in an enlarged sectional view of a main portion of FIG. 7, this type of electroluminescent lamp 50 is a transparent conductive film having transparent electrodes 40b and 40c such as ITO formed on both sides of a transparent film 40a by vapor deposition or the like. The light emitting layer 41, the reflective insulating layer 42, the back electrode 43, and the electrode pad 44 are formed on one surface of the transparent electrode 40b using the substrate 40 as a base material, and the electrode pad 45 (not shown) is formed on the other surface of the transparent electrode 40c. ), After forming the electrode pads on both sides
Leads 46, 47, 48 are connected to 44, 45 and back electrode 43, respectively, and the thickness is reduced by fixing with heat seal tape (not shown). Some are omitted. Then, the lead 47 of the transparent electrode 40c as the third electrode is connected to the lead 4 of the back electrode 43.
By electrically connecting to the electrode 8, the transparent electrode 40c, which is the third electrode located on both sides of the transparent electrode 40b, and the back electrode 43 have the same potential, so that noise during AC driving can be prevented. If grounded, an electromagnetic shield can be formed. Therefore, when the three-electrode-structured electroluminescent lamp 50 is used for a backlight of a liquid crystal, an AC high voltage applied to the EL element is shielded, so that electromagnetic noise is reduced and electrostatic coupling with the liquid crystal is cut off. As a result, mutual attraction force is reduced and noise is reduced.

[0004]

In recent years, with the rapid progress of miniaturization and weight reduction of electronic equipment having a liquid crystal display, a thin electric field provided with noise prevention and electromagnetic shielding for a backlight of a liquid crystal display has been developed. The demand for light emitting lamps is increasing. However, the above three-electrode electroluminescent lamp
In the 50, since the third electrode lead and the EL element lead were connected to each other on the front and back in separate steps and fixed individually with heat seal tape or the like, it took a lot of man-hours to connect and reinforce the lead, resulting in cost reduction. There was a problem of getting high. In addition, there is also a problem that the leads are led out from both sides, so that the leads become thick.

Accordingly, an object of the present invention is to provide a method for inexpensively manufacturing a thin electroluminescent lamp provided with noise prevention and electromagnetic shielding suitable for use as a backlight for a liquid crystal display used in small portable electronic equipment and the like. It is to provide.

[0006]

According to a method of manufacturing an electroluminescent lamp of the present invention, a transparent electrode, a light emitting layer, a reflective insulating layer, and a back electrode are laminated on a back side of an insulating transparent substrate to form an EL element. In the method for manufacturing an electroluminescent lamp in which a transparent third electrode is formed on the surface side of the insulating transparent substrate and leads are connected to the electrodes, a plurality of leads are connected on an insulating adhesive tape, Is folded in two with the lead inside, the EL element and the insulating transparent substrate on which the third electrode is formed are sandwiched, and the EL element lead provided on one folded piece is EL.
The third electrode lead is connected to the transparent electrode and the back electrode of the device, and the third electrode lead provided on the other folded piece is connected to the third electrode. By this means, all the leads are attached on the same surface of the insulating adhesive tape, so that the number of lead connection steps can be reduced, and the lead can be attached simultaneously to the front and back of the electroluminescent lamp by one heat seal. Man-hours can also be reduced.

Further, the end surface of the insulating adhesive tape to which a plurality of leads are connected on the lead lead-out side is protruded from the end surface of the EL element and is folded in two to form an insulating transparent substrate on which the EL element and the third electrode are formed. It is characterized by being pinched. By this means, the connection strength of the lead can be improved in addition to the above effects.

Further, a transparent electrode, a light emitting layer, a reflective insulating layer, and a back electrode are laminated on the back side of the insulating transparent substrate to form an EL element, and a transparent third electrode is formed on the front side of the insulating transparent substrate. In the method of manufacturing an electroluminescent lamp for forming and connecting a lead to the electrode, a conductive portion is formed on a part of an insulating adhesive tape, a lead for an EL element is connected to another part, and then the tape is connected to a lead. And the conductive part is folded inward, sandwiching the insulating transparent substrate on which the EL element and the third electrode are formed, and the leads arranged on one of the folded pieces are respectively connected to the transparent electrode and the back electrode of the EL element. And the conductive portion provided on the other folded piece is connected to the third electrode and the back electrode lead. By this means, since the lead for the back electrode also serves as the lead for the third electrode, the number of leads is reduced by one, and an electromagnetically shieldable electroluminescent lamp with a reduced number of lead connection steps can be provided. In addition, since the third electrode lead is not required, the thickness of the electroluminescent lamp can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a method for manufacturing an electroluminescent lamp according to the present invention will be described with reference to FIGS. The electroluminescent lamp 11 has a structure as shown in an enlarged perspective view of a main part in FIG. First, a transparent electrode 1b such as ITO is deposited on the inner surface of the transparent film 1a, and a transparent electrode 1c such as ITO is deposited as a third electrode on the outer surface of the transparent film 1a. In a shape avoiding the formation position of the power supply electrode pad on the transparent electrode 1b, the light emitting layer 2 in which a phosphor in which zinc sulfide is activated by copper is dispersed in a fluororesin is printed, and barium titanate or the like is printed thereon. A reflective insulating layer 3 in which a white high dielectric substance is dispersed in a fluororesin is printed, and then a back electrode 4 made of a conductive paste such as silver or carbon and an electrode pad 5 for a transparent electrode 1b are formed by printing. Next, an insulating overcoat layer 7 is printed using a melamine resin, an epoxy resin, or the like in a pattern excluding the power supply section of the back surface electrode 4 and the electrode pad 5. Further, the third electrode
Electrode pads 6 made of a conductive paste such as silver or carbon are printed on 1c to form EL elements.

Next, the lead connection method of the present invention will be described. First, as shown in FIG. 2, a heat-sealing tape 9 having a thermoplastic adhesive layer 9b provided on one side of a base film 9a.
Leads 8a, 8b, at predetermined intervals on insulating adhesive tape such as
The electrode sheet 10 connected to the base of 8c is formed. Next, the electrode sheet 10 is bent at a dotted line portion A between the lead 8a and the lead 8c, and the electrode pad 5 of the lead 8a and the transparent electrode 1b is sandwiched by the insulating transparent substrate on which the EL element and the third electrode are formed.
The lead 8b and the back electrode 4 and the lead 8c and the electrode pad 6 of the third electrode 1c are arranged so as to be in contact with each other. The obtained electroluminescent lamp 11 having a three-electrode structure is obtained.

In this configuration, since all the leads are previously mounted on the same surface of the heat seal tape, the number of lead connection steps can be reduced. In addition, the lead can be simultaneously attached to the front and back of the electroluminescent lamp by one heat seal, so that the man-hour for attaching the lead can be reduced. As a modification, as shown in FIG.
Are arranged so as to protrude from the end face of the EL element in the lead take-out direction, and the leads 8a, 8b, 8c are covered with the protruding portions on the front and back of the heat seal tape 9, whereby the adhesive layer 9b of the protruding portion is formed. By bonding, the tensile strength of the lead can be improved.

Next, this three-electrode-structured electroluminescent lamp 11 is
As shown in FIG. 4, double-sided adhesive tapes 13, 1
After fixing to liquid crystal or liquid crystal holder 14 with 3, transparent electrode 1
AC power is supplied to the power supply portions b and the back electrode 4 via the leads 8a and 8b to emit light. At this time, the lead 8c derived from the third electrode 1c is grounded. As a result, the alternating high voltage applied to the transparent electrode 1b is shielded by the third electrode 1c, so that the electrostatic coupling between the transparent electrode 1b and the liquid crystal or the liquid crystal holder 14 is cut off, and the mutual attractive force is reduced. The noise will be reduced. Also, the third electrode 1c is not grounded and the back electrode 4
The noise can also be reduced by connecting with. The transparent electrodes 1b and 1c of the electroluminescent lamp may be formed by printing a paste in which a transparent conductive powder is dispersed in a resin.

Next, a second embodiment of an electroluminescent lamp having a three-electrode structure according to the present invention will be described with reference to FIG.
The electroluminescent lamp 20 of the second embodiment has a structure as shown in an enlarged perspective view of a main part of FIG. The electroluminescent lamp 20 first has a transparent electrode 21b such as ITO on the inner surface of a transparent film 21a.
On a transparent electrode 21b of a transparent conductive film 21 in which a transparent electrode 21c of ITO or the like is deposited as a third electrode on the outer surface,
A light emitting layer 22 in which a phosphor obtained by activating zinc sulfide with copper is dispersed in a fluororesin, and a reflective insulating layer 23 in which a white high dielectric substance such as barium titanate is dispersed in a resin are formed by printing. Next, a back electrode 24 made of a conductive paste such as silver or carbon and an electrode pad 25 for a power supply portion to the transparent electrode 21b are formed by printing. Next, the overcoat layer 27 for insulation is
It is formed by printing in a pattern excluding 24 and the electrode pads 25.
Further, an electrode element 26 is printed on the third electrode 21c using a conductive paste to form an EL element.

Next, a method of connecting leads will be described. As shown in FIG. 6, a conductive portion 30 is provided on a heat seal tape 29 having a thermoplastic adhesive layer 29b disposed on one surface of a base film 29a, and leads 28a, 28b are provided at other predetermined positions.
Is formed, the dotted line portion B of the electrode sheet 31 is bent, the insulating transparent substrate on which the EL element and the third electrode are formed is sandwiched, and the electrode pad 25 of the lead 28a and the transparent electrode 21b is connected to the lead. 28b and the back electrode 24, and the conductive portion 30 and the electrode pad 26 of the third electrode 21c and the lead 28b are arranged so as to be connected to each other. And the third electrode 21c
And an electroluminescent lamp 20 having a three-electrode structure in which the back electrode 24 is conducted. A part of the conductive portion 30 is the third portion via the electrode pad 26.
The other portion protrudes from the end face of the EL element and is connected to the back electrode lead 28b. By forming the protruding portion, conduction between the back electrode lead 28b and the third electrode can be easily achieved. Conductive part 30 is connected to back electrode lead 28b
At the time of connection, the end face may be subjected to insulation treatment so that the conductive portion 30 does not contact the end face of the transparent electrode 21b. In this electroluminescent lamp 20, since the third electrode 21c and the back electrode 24 having the same potential sandwich the transparent electrode 21b, noise during AC driving can be prevented. With this configuration, the same effect as in the first embodiment can be obtained, and the lead mounting portion can be made thinner because the leads are arranged on the same surface. The conductive portion 30 provided on the heat seal tape 29 is formed by means of printing a conductive paste, depositing a conductive material, attaching a conductive tape, or the like.

[0015]

According to the present invention, since the lead for emitting light from the EL element and the lead for the third electrode are mounted on the same surface of an insulating adhesive tape such as a heat sealing tape, the number of steps for connecting the leads can be greatly reduced. In addition, the lead can be attached to the front and back of the electroluminescent lamp at the same time with one heat seal, so the man-hour for mounting the lead can be reduced, the manufacturing man-hour has been greatly reduced, and the inexpensive electroluminescent lamp with noise prevention and electromagnetic shielding has been applied. Can be provided. In addition, a conductive portion is provided on an insulating adhesive tape such as a heat seal tape, and the third electrode and the lead for the back surface electrode are electrically connected using the conductive portion, so that the lead mounting portion of the electroluminescent lamp is provided. It is possible to provide an inexpensive electroluminescent lamp that can be reduced in thickness and electromagnetically shielded.

[Brief description of the drawings]

FIG. 1 is an enlarged perspective view of a main part of an electroluminescent lamp having a three-electrode structure for explaining a first embodiment of the present invention.

FIG. 2 is a perspective view of an electrode sheet for explaining a lead connection method according to the first embodiment of the present invention.

FIG. 3 is an enlarged perspective view of a main part of an electroluminescent lamp having a three-electrode structure for describing a modification of the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of a structure manufactured according to the first embodiment of the present invention.
Cross-sectional view of an electroluminescent lamp with an electrode structure mounted on a liquid crystal display

FIG. 5 is a partially cut-away enlarged perspective view of a three-electrode structure electroluminescent lamp for explaining a second embodiment of the present invention.

FIG. 6 is a perspective view of an electrode sheet for describing a lead connection method according to a second embodiment of the present invention.

FIG. 7 is an enlarged sectional view of a main part of a conventional three-electrode structure electroluminescent lamp.

[Explanation of symbols]

 1,21 Transparent conductive film 1a, 21a Transparent film 1b, 21b Transparent electrode 1c, 21c Third electrode 2,22 Light emitting layer 3,23 Reflective insulating layer 4,24 Back electrode 5,6,25,26 Electrode pad 7,27 Overcoat layer 8a, 8b, 8c, 28a, 28b Lead 9, 29 Heat seal tape 10, 31 Electrode sheet 11, 20 Electroluminescent lamp 30 Conductive part

Claims (4)

[Claims] 1. An EL element is formed by laminating a transparent electrode, a light emitting layer, a reflective insulating layer, and a back electrode on the back side of an insulating transparent substrate, and a transparent third electrode is formed on the front side of the insulating transparent substrate. In the method of manufacturing an electroluminescent lamp in which a lead is connected to the electrode, a plurality of leads are connected to an insulating adhesive tape, and then the tape is folded in two with the lead inside and the EL element and the third An insulative transparent substrate on which electrodes are formed is sandwiched, a lead provided on one of the folded pieces is connected to the transparent electrode and the back electrode of the EL element, and a lead provided on the other folded piece is connected to the third electrode. A method for manufacturing an electroluminescent lamp. 2. An EL element is formed by laminating a transparent electrode, a light emitting layer, a reflective insulating layer, and a back electrode on the back side of an insulating transparent substrate, and forming a transparent third electrode on the front side of the insulating transparent substrate. In the method of manufacturing an electroluminescent lamp for forming and connecting a lead to the electrode, a conductive portion is formed on a part of an insulating adhesive tape, a lead is connected to another portion, and then the tape is connected to the lead and the conductive portion. Is folded inward with an insulated transparent substrate on which the EL element and the third electrode are formed, and the lead provided on one of the folded pieces is connected to the transparent electrode and the back electrode of the EL element, respectively. The conductive portion provided on the other folded piece is
A method for manufacturing an electroluminescent lamp, comprising connecting to an electrode and a back electrode lead. 3. An insulative transparent substrate on which an EL element and a third electrode are formed is formed by projecting an end face of a lead-out side of an insulative adhesive tape to which a plurality of leads are connected from an end face of an EL element and folding it into two. The method for manufacturing an electroluminescent lamp according to claim 1, wherein the lamp is sandwiched. 4. The method according to claim 2, wherein a part of the conductive portion protrudes from an end face of the EL element and is connected to the back electrode lead.