JP2000260558A - Fixing structure for electroluminescence element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing structure which makes vibration sound produced by an electroluminescence element completely inaudible. SOLUTION: In this fixing structure, an electroluminescence element 1 is adhesively fixed, at a plurality of portions to an upper surface 22a or an under surface of a fixed substrate 22 by means of an adhesive 23. The plurality of portions are provided at fixed intervals, and the fixed substrate 22 is a transmissive display body such as a liquid crystal panel. Thus, the frequency of vibration sound of the electroluminescence element 1 is turned into a vibration frequency in a high-frequency range and makes it inaudible to human ears.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing structure for electroluminescence, and more particularly to a fixing structure for preventing sound noise.

[0002]

2. Description of the Related Art Electroluminescence (hereinafter, referred to as EL) is used as a backlight of a liquid crystal panel used in electronic devices such as a portable timepiece and a cellular phone. This EL generally has a structure as shown in FIG. That is, the transparent electrode 3, the light emitting layer 4, the dielectric layer 5, and the back electrode 6 are sequentially laminated on the lower surface of the transparent substrate 2, and the insulating film 7 is provided so as to cover them, thereby constituting the EL1. . Although not shown, a part of the transparent electrode 3 and the back electrode 6 is extended to the outer edge, and a terminal for voltage application is provided at the extended end. .

[0003] Here, the transparent substrate 2 constituting the EL1 is provided.
Is glass or PET excellent in transparency, insulation, moisture resistance, etc.
(Polyethylene terephthalate) film or the like is used. The transparent electrode 3 is made of indium oxide (In ₂ O ₃ ).
Obtained by doping tin oxide (SnO ₂ ) into ITO
(Indium Tin Oxide) powder is formed by vacuum deposition. The light emitting layer 4 is made of zinc sulfide (ZnS).
A small amount of activator (metal or halogen element)
The phosphor powder obtained by doping is dispersed in a high dielectric resin binder such as a cyanoresin compound, and is formed by a printing method or the like. The dielectric layer 5 is formed by dispersing a high dielectric metal such as barium titanate in a high dielectric resin binder by a printing method or the like. The dielectric layer 5 also has a reflection function by barium titanate. The back electrode 6 is formed by printing silver powder or graphite powder into a paste. Further, the insulating film 7 is formed by printing with a resin having excellent moisture resistance and insulating properties, or a resin film is formed on the transparent substrate 2.
And thermocompression bonding.

When a predetermined voltage is applied to the transparent electrode 3 and the back electrode 6 of the EL 1 thus formed through an application terminal provided at an extended end thereof, the light emitting layer 4 emits light,
The emitted light passes through the transparent electrode 3 and the transparent substrate 2 and radiates to the outside, illuminating the surroundings brightly.

However, when the light emitting layer 4 emits light, a humming vibration sound appears, and the vibration sound is heard as sound noise. In particular, when the EL is used for a backlight of a liquid crystal panel used in a mobile phone, this sound noise is heard during a call, resulting in a very harsh sound, which affects the call.

One of the techniques for suppressing this noise is disclosed in Japanese Patent Application Laid-Open No. 10-215085. This has the structure shown in FIG. 6, and attaches the EL 13 provided below the liquid crystal panel 12 to the printed circuit board 11 via a foamed sponge 15 with a double-sided adhesive. The foam sponge 15 here has a function of absorbing the vibration of the EL 13 and suppressing the vibration, and plays a role of reducing the sound noise.

[0007]

However, the technique disclosed above absorbs the vibration of the EL by the vibration suppressing material to reduce the vibration, thereby reducing the sound noise, and completely eliminates the vibration sound. Not something. In addition, the effect is small when the vibration suppressing material such as foam sponge is thin, and the effect is more significant when the vibration suppressing material is thicker, so that the entire thickness including the liquid crystal panel and the like becomes thicker. Problems arise.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a fixing structure for completely preventing the vibration sound generated from EL from being heard. is there. And, in order to achieve this object, the present invention provides a transparent electrode, a luminescent layer,
A dielectric layer and a back electrode are sequentially laminated, and an EL formed by covering with an insulating film is bonded and fixed to an upper surface or a lower surface of a fixed base at a plurality of locations via an adhesive.

[0009] Further, the plurality of portions are provided at fixed intervals, respectively.

[0010] Further, the fixed base is a transmissive display.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An EL fixing structure according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main part showing an EL fixing structure according to a first embodiment of the present invention. In the drawings, the same members as those in the prior art are denoted by the same reference numerals.

In FIG. 1, the fixing structure of this embodiment is E
L <b> 1 is bonded and fixed at a plurality of locations on the upper surface of the fixed base 22 by the adhesive 23. E here
Since L1 has the same configuration as EL described in the related art, a cross-sectional view thereof is omitted. The upper surface 1a of the EL1 corresponds to the emission surface side of the emitted light, and the lower surface 1b corresponds to the surface side opposite to the emission surface side. The fixed base 22 is a rigid printed board, a rigid metal board provided specifically for fixing, or the like. The fixed base 22 is not particularly limited to a material or the like, and may be a rigid base. The adhesive 23 is an adhesive which adheres very strongly when the EL 1 and the fixed base 22 are adhered and fixed, and hardens naturally by itself. As such an adhesive, an epoxy resin adhesive or an acrylic resin adhesive is preferably selected.

A plurality of places are bonded and fixed by the adhesive 23. In particular, it is preferable to provide the fixed portions with a constant interval m in a dot matrix shape as shown in FIG. FIG. 2 is a plan view of a main part showing a bonding and fixing portion.

Further, it is preferable that the interval m for bonding and fixing is so small that adjacent fixing points are not connected to each other.

The interval m of the adhesive fixation can be set in advance so that the vibration sound frequency of the EL1 becomes a frequency exceeding a human audible range, that is, a frequency in a high frequency region. Although the frequency in the human audible range varies slightly from person to person, it is hardly audible in a high frequency region of about 15 kHz or more.

In the method of bonding and fixing with the above-mentioned adhesive, an adhesive 23 is formed on the upper surface 1a of the fixed base 22 by printing or the like, and the EL1 and the fixed base 22 are bonded to each other by a heat curing method, an ultraviolet curing method, or the like. It can be firmly fixed by adhesive fixing.

By adopting the above fixing structure, the EL
Is firmly fixed to a rigid fixed base with an adhesive. Moreover, it is firmly fixed with a large number of fixing points at fixed small intervals. Therefore, E at the fixed point
The vibration of L almost disappears, and the vibration appears within a small distance between the fixed point and the adjacent fixed point. Moreover, since the vibration sound appears as vibration having a frequency in a high frequency range, it can hardly be heard by human ears.

Further, since a large number of fixed points are arranged at a fixed interval, the same frequency is obtained as the frequency appearing between the fixed points, so that no audible vibration sound appears.

In this embodiment, the bonding and fixing portions are provided in a dot matrix shape. However, the same effect can be obtained by a grid-like bonding and fixing provided at regular intervals as shown in FIG.

In this embodiment, the structure for bonding and fixing the EL and the fixed base is shown. However, the present invention can be applied to equipment and devices in which a liquid crystal panel, a transmissive display panel, and the like are provided above the EL. is there.

Next, a fixing structure according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a sectional view showing a fixing structure according to the second embodiment of the present invention. This embodiment shows a fixing structure in which a liquid crystal panel which is a transmissive display is used as a fixing base and EL is provided as a backlight of the liquid crystal panel.

In the fixing structure of the present embodiment, the EL 1 is firmly bonded and fixed to the lower surface 12 b of the liquid crystal panel 12 at a plurality of positions with an adhesive 23. The liquid crystal panel 22 here is formed by laminating two glass substrates and is rigid. The upper surface 12a corresponds to the display side, and the lower surface 12b corresponds to the opposite side of the front surface. In addition, the EL 1 is bonded and fixed with the upper surface 1a corresponding to the light emitting surface facing the liquid crystal panel 22 side.

The EL1 and the liquid crystal panel 12 are bonded and fixed firmly at a large number of points in a dot matrix like in the first embodiment, and each bonded point is fixed at a fixed interval. It is provided in.

Further, the fixed interval is set so that the vibration sound frequency of EL1 becomes a frequency in a high frequency region, as in the first embodiment.

Here, as the adhesive 23, a transparent epoxy resin adhesive or a transparent acrylic resin adhesive is selected.

Under the above-mentioned fixed structure, the vibration sound of the EL has a frequency in a high frequency range and is hardly audible to human ears.

Also, since the EL and the liquid crystal panel are bonded on many small surfaces, the adhesive can escape to the surrounding air space at the time of bonding, and the gap between the EL and the liquid crystal panel can be made uniform. Can be laminated. When this uniform gap is obtained, the occurrence of moire fringes can be prevented.

In this embodiment, a liquid crystal panel is used as a fixed base as a transmissive display. However, the present invention is applicable to various transmissive displays such as a transmissive timepiece dial or a transmissive signboard or nameplate. The above fixing structure can be applied.

[0029]

As described in detail above, according to the present invention. Since the vibration sound of the EL becomes a vibration frequency in a high frequency region, the sound cannot be heard by human ears, and the call has no influence as sound noise at all.

Further, when used in a backlight structure of a liquid crystal panel, generation of moire fringes can be prevented.

Further, since the manufacturing method is simple and can be performed in a small number of working steps, the manufacturing can be performed at low cost.

Further, since the fixing structure of the present invention is a structure in which the EL is firmly bonded and fixed at a plurality of locations, the thickness of the adhesive is not so required. Therefore, it can contribute to the effect of thinning.

[Brief description of the drawings]

FIG. 1 is an essential part cross-sectional view showing a fixing structure of electroluminescence according to a first embodiment of the present invention.

FIG. 2 is a plan view of a main part showing a bonding and fixing point in FIG. 1;

FIG. 3 is a plan view of a main part showing another adhesive fixing place.

FIG. 4 is a sectional view showing an electroluminescence fixing structure according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a structure of a conventional electroluminescence.

FIG. 6 is an essential part cross-sectional view showing a conventional structure for fixing electroluminescence.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electroluminescence 12 Liquid crystal panel 12a Upper surface 12b Lower surface 22 Fixed base 22a Upper surface 23 Adhesive

Claims (3)

[Claims] 1. A transparent electrode, a luminous body layer,
Electroluminescence fixed by sequentially laminating a dielectric layer and a back electrode, and covering and fixing the electroluminescence formed by covering with an insulating film at a plurality of locations via an adhesive on the upper or lower surface of the fixed base. Construction. 2. The structure for fixing electroluminescence according to claim 1, wherein said plurality of portions are provided at fixed intervals. 3. The fixing structure for electroluminescence according to claim 1, wherein the fixing base is a transmissive display.