JPH11329747A - Electroluminescent lamp and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroluminescent lamp which is thin and less expensive, has a three-electrode structure and is suitable for a back light of a liquid crystal display used for a small portable electronic apparatus or the like and to which noise prevention and electromagnetic shielding are applied. SOLUTION: In this thin electroluminescent lamp 10, an EL element is formed on a nearly half part 1c of a transparent electrode 1b formed on a transparent film 1a, the other nearly half part 1d is used as a third electrode, the boundary of the transparent electrodes 1c, 1d is separated by cutting half-and-half, the transparent film 1a is folded along the half-and-half cutting line, the third electrode 1d is superposed on the EL element and thus, a three-electrode structure is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent lamp and a method of manufacturing the same, and more particularly to a thin three-electrode electroluminescent lamp provided with a noise prevention and electromagnetic shield suitable for a backlight of a liquid crystal display, and a method of manufacturing the same. It is about the method.

[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.

An electroluminescent lamp 30 of this type is described, for example, in Japanese Utility Model Laid-Open Publication No. 3-37795, and is a non-light-emitting side of an electroluminescent lamp 40 as shown in an enlarged sectional view of a main part of FIG. It has a structure in which the third electrode sheet 50 is adhered to the back side with an adhesive or the like. The electroluminescent lamp 40 includes a back electrode 41 such as an aluminum foil, a reflective insulating layer 42 in which barium titanate powder is dispersed in a resin binder, a light emitting layer 43 in which zinc sulfide phosphor is dispersed in a resin binder, and a transparent film. An EL element 45 formed by laminating a transparent electrode 44 made of ITO or the like formed thereon is generally sealed with moisture-proof outer skin films 48 and 49 from above and below with lead electrodes 46 and 47 led out from both electrodes. It is a target.

[0004] The third electrode sheet 50 is formed by applying a metal foil 51 such as aluminum to a resin film 52 from above and below.
Insulation by sealing with 53
Is derived. Then, the lead 54 of the third electrode sheet 50 is connected to the lead electrode 4 of the transparent electrode 44 of the electroluminescent lamp 40.
6, the transparent electrode 44 and the third electrode 51 located on both sides of the back electrode 41 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 electroluminescent lamp 40 is used for a liquid crystal backlight,
Since the AC high voltage applied to the EL element is shielded, electromagnetic noise is reduced, and at the same time, the electrostatic coupling with the liquid crystal is cut off, so that the mutual attraction force is reduced and the noise is reduced.

[0005]

In recent years, as electronic devices having a liquid crystal display unit have been rapidly reduced in size and weight, 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, in the conventional electroluminescent lamp 30 having a three-electrode structure, the third electrode sheet 50 uses a metal foil 51 made of aluminum or the like sealed with resin sheets 52 and 53 from above and below. There is a problem that a design is required every time, an adhesive layer is required for attaching the third electrode sheet 50, a large number of man-hours are required for alignment, and the cost is extremely high.

Further, transparent electrodes (I) are provided on both sides of the transparent film.
A light emitting layer, a reflective insulating layer, a back surface electrode, and an electrode pad are formed on a transparent electrode on one side of a transparent conductive film on which a transparent conductive film formed with TO or the like is formed to form an EL element, and the transparent electrode on the other side is formed. After an electrode pad is formed thereon as the third electrode, leads are connected to the electrode pads on both surfaces and the back electrode and fixed with a heat seal tape to reduce the thickness, and further, the third electrode is aligned and mounted. Although there is an electroluminescent lamp having a three-electrode structure in which man-hours are omitted, there is a problem that a large number of man-hours are required for attaching the leads and attaching the heat seal tape since the leads need to be led out from both sides.

An object of the present invention is to provide a thin, three-electrode-structured electroluminescent lamp which is suitable for use as a backlight of a liquid crystal display used in a small portable electronic device or the like and which is provided with an electromagnetic shield. It is to provide to.

[0008]

An electroluminescent lamp according to the present invention comprises:
An EL element is formed by using a part of the transparent electrode formed on the transparent film as a transparent electrode for an EL element, and the other part of the transparent electrode is used as a third electrode. The third electrode is bent to form the EL element. It is characterized by being polymerized.

The transparent electrode is divided, one of the transparent electrodes is used for an EL element, the other is used for a third electrode, and the transparent electrode for the third electrode is provided via a transparent film. Characterized by being polymerized on the outside of a transparent electrode for use.

Further, the transparent electrode for the third electrode is electrically connected to the transparent electrode for the EL element, and is superposed on the outside of the back electrode of the EL element via an insulating overcoat layer.

Further, the transparent electrode is electrically separated by half-cut, and is folded and polymerized along the half-cut line.

The manufacturing method includes a step of sequentially laminating a light emitting layer, a reflective insulating layer, and a back electrode on a part of a transparent electrode formed on a transparent film to form an EL element; Forming a lead, connecting a lead to an electrode pad, dividing the transparent electrode, and folding another portion of the transparent electrode along the dividing line to overlap the EL element. I do.

A step of forming an EL element by sequentially laminating a light emitting layer, a reflective insulating layer, and a back electrode on a part of the transparent electrode formed on the transparent film; and a step of forming an electrode pad on the transparent electrode. Forming an insulating overcoat layer, connecting a lead to the electrode pad, and bending another portion of the transparent electrode to overlap the back electrode of the EL element via the overcoat layer. Features.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an electroluminescent lamp according to the present invention will be described with reference to FIGS.
The electroluminescent lamp 10 according to the first embodiment has a structure as shown in an enlarged sectional view of a main part in FIG. That is, this electroluminescent lamp is provided with a transparent electrode 1 formed on a transparent film 1a.
b is electrically divided into two, an EL element is formed using one transparent electrode 1c as a transparent electrode for an EL element, and the other transparent electrode 1d is used as a third electrode, and a transparent film 1a is formed along the dividing line.
Is bent inward so that the third electrode is superposed on the outside of the transparent electrode 1c of the EL element.

The method for manufacturing the electroluminescent lamp 10 is as follows.
ITO formed on the transparent film 1a as shown in FIG.
On a substantially half (1c) of the transparent electrode 1b, a light emitting layer 2 in which a phosphor obtained by activating zinc sulfide with copper is dispersed in a resin, and a white high dielectric substance such as barium titanate is coated on the resin. The reflection insulating layer 3 dispersed therein is formed. Next, a back electrode 4 made of a conductive paste such as silver or carbon is formed on the reflective insulating layer 3.
The electrode pad 5 is formed on the transparent electrode 1c, and the electrode pad 6 for the third electrode is formed on the transparent electrode 1d by printing. Next, as shown in FIG. 2B, an insulating overcoat layer 7 is printed and formed on the back electrode 4 in a pattern excluding the power supply portion of the back electrode, the power supply portion of the electrode pad 5, and the third electrode portion. Next, the leads 8a, 8b and 8c are arranged on the power supply portion of the back electrode 4 and the electrode pads 5 and 6, and the heat seal tape 9
Fix with. Next, as shown in FIG. 2 (c), the position AA portion of substantially half of the transparent electrode 1b is half-cut with a Thomson blade or the like to be divided, and the left and right transparent electrodes 1c and 1d are electrically insulated. It is separated into a transparent electrode 1c for the element and a transparent electrode 1d for the third electrode. Next, the transparent film 1a is bent inward along the half-cut line as shown in the main part enlarged sectional view of FIG. 1, and the transparent electrode 1d for the third electrode is disposed outside the transparent electrode 1c for the EL element. Then, an electroluminescent lamp 10 having a three-electrode structure is obtained. The half-cut is not limited to the Thomson blade and may be any method such as laser or etching.

In this configuration, since three leads can be mounted on the same surface as shown in FIG. 2B, the man-hour for mounting the leads can be greatly reduced as compared with the conventional mounting from both surfaces. Installation by an automatic machine is also easy. Further, since the third electrode is bent on the basis of the half-cut line, the positional accuracy of the third electrode with respect to the EL element is significantly improved.

Next, as shown in FIG. 3, the above-described three-electrode-structured electroluminescent lamp 10 is fixed to a liquid crystal or a liquid crystal holder 13 with double-sided adhesive tapes 12, 12 via butyl rubber 11, and then the transparent electrode 1c and the back surface are fixed. Lead 8 to each power supply part of electrode 4
b, 8a (not shown) to supply AC power to emit light. At this time, a lead 8c (not shown) derived from the third electrode (transparent electrode 1d) is grounded. As a result, the AC high voltage applied to the transparent electrode 1c is shielded by the third electrode, so that the electrostatic coupling between the transparent electrode 1c and the liquid crystal or the liquid crystal holder 13 is cut off, and the mutual attractive force is reduced. Noise is reduced. The noise can also be reduced by connecting the third electrode to the back electrode 4 without grounding. The transparent electrode 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 according to the second embodiment has a structure as shown in an enlarged sectional view of a main part in FIG. That is, in this electroluminescent lamp, the transparent electrode is not divided, the third electrode transparent electrode 21d is electrically connected to the EL element transparent electrode 21c, and the back surface of the EL element is interposed via the insulating overcoat layer. It is characterized by being polymerized on the outside of the electrode 24.

The method of manufacturing the electroluminescent lamp 20 is as follows.
On a substantially half 21c of a transparent electrode 21b such as ITO formed on a transparent film 21a, a luminescent layer 22 in which a phosphor obtained by activating zinc sulfide with copper is dispersed in a resin, and a luminescent layer 22 such as barium titanate or the like is formed thereon. A reflective insulating layer 23 in which a white high dielectric substance is dispersed in a resin is formed. Next, a back electrode 24 made of a conductive paste such as silver or carbon is formed on the reflective insulating layer 23, an electrode pad 25 is formed on the transparent electrode 21c, and an electrode pad 26 for a third electrode is formed on the transparent electrode 21d at the same time. . Next, an overcoat layer (not shown) for insulation is
On the third electrode 21d, a pattern is formed by printing except for the electrode pads 25, 26 and the power supply portion of the back electrode, and the leads 28a, 28b, 28c are arranged on the power supply portion of the back electrode 24, the electrode pads 25, 26. Then, it is fixed with a heat seal tape 29 from above. Next, it is bent at a position approximately half of the transparent film 21a, and the third electrode 21d is arranged outside the overcoat layer.
Get. With this configuration, the same effects as those of the first embodiment can be obtained. Further, since the transparent films 21a and 21a are used on both sides, there is no fear of damaging the EL element.

Further, as a modification of the second embodiment,
As shown in FIG. 5, the electrode pads 25 and 26 are combined to form the common electrode pad 30 for the transparent electrode 21c and the third electrode 21d, so that there is no need to provide a lead for the third electrode, and the number of leads is reduced by one. And the number of manufacturing steps can be further reduced.

[0021]

According to the electroluminescent lamp of the present invention, an EL element is formed on substantially half of a transparent electrode formed on a transparent film,
Since the other half is bent and overlapped with the EL element to form the third electrode, the leads can be mounted collectively on the same surface, and the man-hour for mounting the leads can be greatly reduced. Further, since the transparent electrode is bent on the basis of a half-cut line that substantially divides the transparent electrode into two parts, the positional accuracy of the third electrode with respect to the EL element is significantly improved. Further, by bending the third electrode toward the back electrode, the front and back surfaces are covered with the transparent film, and the EL element can be protected. Further, by forming an electrode pad common to the transparent electrode and the third electrode, it is not necessary to provide a lead for the third electrode, and the number of manufacturing steps can be further reduced. An electroluminescent lamp can be provided.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part of a three-electrode structure electroluminescent lamp according to a first embodiment of the present invention.

FIG. 2 is a plan view for explaining a method of manufacturing an electroluminescent lamp having a three-electrode structure according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing an example in which a three-electrode structure electroluminescent lamp according to the first embodiment of the present invention is mounted as a liquid crystal backlight.

FIG. 4 is an enlarged sectional view of a main part of an electroluminescent lamp having a three-electrode structure showing a second embodiment of the present invention.

FIG. 5 shows a modification 3 of the second embodiment of the present invention.
Enlarged sectional view of main part of electroluminescent lamp with electrode structure

FIG. 6 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 Transparent electrode 1d, 21d for EL element Transparent electrode for third electrode 2,22 Light emitting layer 3,23 Reflective insulating layer 4,24 Back surface Electrode 5, 6, 25, 26, 30 Electrode pad 7, 27 Overcoat layer 8a, 8b, 8c, 28a, 28b, 28c Lead 10, 20 Electroluminescent lamp 9, 29 Heat seal tape

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[Procedure amendment]

[Submission date] May 20, 1998

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

The present invention relates to an electroluminescent lamp and a method for manufacturing the same.

Claims (6)

[Claims] An EL element is formed by using a part of a transparent electrode formed on a transparent film as a transparent electrode for an EL element, and the other part of the transparent electrode is used as a third electrode, and the third electrode is bent. An electroluminescent lamp having a three-electrode structure formed by polymerizing the EL element. 2. A transparent electrode is divided, and one of the transparent electrodes is E
The other transparent electrode for the L element is used for the third electrode, and the transparent electrode for the third electrode is polymerized outside the transparent electrode for the EL element via a transparent film. Item 3. An electroluminescent lamp having a three-electrode structure according to Item 1. 3. The transparent electrode for the third electrode is electrically connected to the transparent electrode for the EL element, and is superposed on the outside of the back electrode of the EL element via an insulating overcoat layer. Item 3. An electroluminescent lamp having a three-electrode structure according to Item 1. 4. An electroluminescent lamp having a three-electrode structure according to claim 2, wherein the transparent electrodes are electrically separated by half-cutting, and are folded and polymerized along the half-cut line. 5. An EL device in which a light emitting layer, a reflective insulating layer, and a back electrode are sequentially laminated on a part of a transparent electrode formed on a transparent film.
A step of forming an element, a step of forming an electrode pad on the transparent electrode, a step of connecting a lead to the electrode pad, a step of dividing the transparent electrode, and bending another portion of the transparent electrode along the division line by EL 3) including a step of superimposing on the element.
A method for manufacturing an electroluminescent lamp having an electrode structure. 6. An EL device in which a light emitting layer, a reflective insulating layer and a back electrode are sequentially laminated on a part of a transparent electrode formed on a transparent film.
A step of forming an element, a step of forming an electrode pad on the transparent electrode, and a step of forming an insulating overcoat layer,
A method for manufacturing an electroluminescent lamp having a three-electrode structure, comprising a step of connecting a lead to an electrode pad and a step of folding another part of the transparent electrode and overlapping the back electrode of the EL element via an overcoat layer.