JP2001210467A - Display device with organic el backlight - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device with an organic EL back light which is integrated into a thin and compact structure at the preceding stage of mounting it on the information equipment and the like, by improving the installing structure of an organic EL back light and a liquid crystal. SOLUTION: The organic EL backlight 3 is formed by covering the organic EL element 22 with an enclosing plate 26 formed by press molding of metal plate. The enclosing plate 26 has nails 27 protruding sideward in more than two places and the nails are bent at right angles. The liquid crystal display device 3 is laid so as to abut on pawls 27 that are bent so as to hold the liquid crystal display device 3. Thus, a liquid crystal display device with organic EL backlight 1 positioned and fixed by the nail 27 is composed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-light-emitting display device such as a liquid crystal display device, and more particularly to a structure for fixing a non-light-emitting display device and an organic EL backlight used for the same.

[0002]

2. Description of the Related Art A liquid crystal display device made by sandwiching a liquid crystal compound between a pair of substrates with electrodes does not emit light by itself, but can perform various displays by power-saving driving. It is used in various devices such as computer display devices.

Conventionally, in a backlight unit used in a non-light emitting display device such as a liquid crystal display device, a cold cathode tube, a hot cathode tube, and a light emitting diode are used as a light source, and light from the light source is passed through a light guide section. Lead to the reflective diffuser,
A device that irradiates light from the back side of a liquid crystal display device is generally employed. When such a backlight unit is used, the number of components is large, and it has been difficult to reduce the weight and thickness.

Further, an inorganic E is used as a backlight unit.
An L element may be used in some cases. By using a thin-film EL element using an inorganic phosphor thin film such as ZnS or a dispersion-type EL element in which inorganic phosphor particles are dispersed in a resin binder having a high dielectric constant to form a sheet, the above-described cold cathode tube and the like can be used. The backlight unit can be made thinner than a backlight unit using the same. However, in order for these inorganic EL elements to emit light,
Since the liquid crystal display device is driven by a low voltage of 10 V or less, each drive control circuit must be provided, while the AC drive requiring a high voltage of approximately 00 V or more is required. The size was large and the cost was high.

Further, there has been proposed an organic electroluminescence device (hereinafter referred to as an organic EL device) having a backlight. It is considered that the light emission of the organic EL element is such that holes and electrons injected from the electrodes are recombined in the light emitting layer, thereby exciting the molecules of the light emitting material constituting the light emitting layer to obtain electroluminescence light emission. ing. For example, in Japanese Patent Application Laid-Open No. 5-34692, a backlight unit composed of an organic electroluminescent element in which a transparent anode, a hole transport layer, a light emitting layer, and a cathode are sequentially laminated on a glass substrate is provided on both sides of a liquid crystal display device. It is described to be disposed so as to surround the side surface. Also, JP-A-9-50
In No. 031, a diffuser plate having a light scattering function is arranged behind a liquid crystal display device, and an organic EL planar illuminant is arranged behind the liquid crystal display device. It is described that a liquid crystal display device that can be illuminated, does not require an inverter circuit, and can freely select a light emission color can be provided.

[0006]

However, the organic E
Although the use of the L element as a backlight unit of a liquid crystal display device is described, there is no description on a fixing method thereof. If they are separately fixed when they are attached to the device, it is necessary to separately perform the alignment, and a space for the alignment and the fixing is required. In particular, in the case of attaching to a device such as a portable terminal, further reduction in thickness, weight, and cost have been demanded, and it was necessary to solve such a point.

In view of the above, the present invention provides an organic EL using a novel fixing structure between an organic EL backlight and a display device.
It is an object to provide a display device with a backlight.

[0008]

According to a first embodiment of the present invention, there is provided a display device using a light-transmitting substrate and the display device through a light-transmitting organic EL element substrate. An organic EL backlight having an organic EL backlight irradiated from the back side, wherein the organic EL backlight includes an organic EL element having at least a pair of electrodes and an organic light emitting layer on the organic EL element substrate. In addition to the above, a sealing plate covering the organic EL element is provided on the back side facing the organic EL element substrate, and the sealing plate has claws at at least two places in a side direction, and
The object is achieved by providing a display device with an organic EL backlight, wherein the display device is fixed with the display device sandwiched from the back side of the display device.

In the invention of this embodiment, since the organic EL backlight and the display device are connected by the nail, the handleability of the backlight display device is improved. Further, the thickness can be easily reduced, and the installation space can be reduced.

According to another embodiment of the present invention, the sealing plate is formed of a metal plate integrally formed with a nail, and the display device is fixed by bending the nail. The above object is achieved by the above-described display device with an organic EL backlight or the above-mentioned display device with an organic EL backlight, wherein the claws are made of a resin having a hook structure. According to the invention using the metal plate in which the claws are integrally formed, the claws can be easily formed, and can be connected without increasing the number of parts. Further, according to the invention using the hook having the hook structure, the work of connecting the organic EL backlight and the display device can be simplified, and the cost can be reduced as a whole.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 4 show a configuration of an embodiment of a display device 1 with a backlight according to the present invention. In FIG. 1, a display device 1 with a backlight is composed of a liquid crystal display device 3 which is a non-light emitting display device, and an organic EL backlight 2 behind which a light emitting surface 2b is arranged as the liquid crystal display device 3 side. . On one of the four sides of the liquid crystal display device 3, a terminal extraction portion 31 a extending from the substrate 31 is provided, and a liquid crystal display device connection terminal 33 is arranged at the center of the terminal extraction portion 31 a so that it can be connected to an external power supply. Have been. On the other three sides, the liquid crystal display device 3 and the organic EL backlight 2 are fixed by a plurality of claws 27.

The liquid crystal display device 3 is formed by arranging a pair of glass substrates 31 and 32 to face each other as shown in FIG. 2, sandwiching a liquid crystal layer (not shown) therebetween, and sealing the peripheral portion with an adhesive. And a display area 34 and a seal area 35 around the display area 34. T for the liquid crystal layer
Liquid crystal molecules such as N liquid crystal and STN liquid crystal are used, and display is performed in a display mode such as TN according to the liquid crystal molecules. A polarizing plate (not shown) is provided outside the glass substrate as needed. In the case of performing dot matrix display, a common electrode and a segment electrode made of an ITO transparent electrode (not shown) linearly patterned are formed on the inner surfaces of the respective glass substrates 31 and 32.

At least one of the substrates 31 has a liquid crystal display terminal take-out portion 31a having one end extended from the other substrate 32.
A connection terminal section 33 for a liquid crystal display device formed by routing the common electrode and the segment electrode described above is formed at a. In this embodiment, the sealing region 3
In 5, the segment electrode or the common electrode is applied to both the segment electrode and the common electrode on the surface of the one substrate 31 by a known method such as conducting the segment electrode or the common electrode from the other substrate 32 side by anisotropic material for each pattern. A corresponding connection terminal portion 33 for the liquid crystal display device is formed, and this is provided at the center of the liquid crystal display device terminal extraction portion 31a.

The organic EL backlight 2 includes an organic EL element 22 formed on a transparent substrate 21 and an organic EL element 2.
2 is covered with the sealing plate 21 on which the claws 27 are formed. Also, as shown in FIG. 2, the organic EL element light-emitting surface 2b is disposed so as to overlap with the liquid crystal display device 3 side. At this time, claws 27 for sandwiching and fixing the liquid crystal display device 3 are provided on three sides of the organic EL backlight 2, and the positioning and fixing of both are performed by the claws 27.

The organic EL element 22 has at least a pair of electrodes and a light emitting layer made of an organic material, and holes and electrons injected from the electrodes are recombined in the light emitting layer, thereby forming the light emitting layer. It is considered that electroluminescence can be obtained by exciting molecules of a light emitting material, and may be referred to as an organic LED element or the like.

FIGS. 3 and 4 show an example of the organic EL backlight 2 of the present embodiment, and FIG.
FIG. 4B is a sectional view taken along the line AA of FIG.
3 shows a cross section. The organic EL element 22 has a light-transmissive electrode 23 having a large work function such as ITO formed on the upper surface of a transparent substrate 21 made of, for example, glass or plastic. After forming the organic EL layer 24, the cathode layer 2 having a small work function such as Al-Li is formed.
The liquid crystal display device 3 is irradiated from the back side through the transparent substrate 21. Further, the organic EL element terminal surface 2 on the opposite side of the light emitting surface 2b of the transparent substrate 21
In a, a pair of organic EL electrode terminals 23a and 25a for causing the organic EL element 22 to emit light are formed on both end surfaces of one side of the transparent substrate 21. The electrode terminal 23a is connected to the anode 23, and the electrode terminal 25a is connected to the cathode 25.

The organic EL layer 24 is not limited to the two-layer structure described above, but may be a hole injection layer / a hole transport layer / a light emitting layer / an electron transport layer, a hole injection layer / a hole transport layer / a light emitting layer. Alternatively, a multilayered structure such as a hole transporting layer / a light emitting layer / an electron transporting layer or a single layered structure may be used. Further, as the hole transport layer, for example, N, N'-diphenyl-
N, N'-bis (3-methylphenyl) 1,1'-biphenyl-4,4'-diamine (Triphenyldiamine, hereinafter T
A low molecular compound such as PD (abbreviated as PD) can be used. As the organic light emitting layer, tris (8-hydroxyquinolinato) aluminum (Tris (8-hydroxyquinolinato) Alum
inium, hereinafter abbreviated as AlQ).

Since the life of the organic EL element 22 tends to be shortened due to the influence of moisture or the like, a sealing plate 26 made of a metal plate covering these laminated structures is disposed so as to face the transparent substrate 21 and its periphery. By forming a sealing structure in which the portions are bonded and fixed with the adhesive 28, the sealing performance is improved and the element life is extended. The gap 29 between the sealing plate 26 and the organic EL element 22 may be provided with an adsorbent for adsorbing moisture or the like contained in the element or the like, or may be filled with silicon oil or the like.

The sealing plate 26 is made of stainless steel, aluminum,
A metal plate made of copper, an alloy thereof, or the like is formed in a predetermined shape, and a claw 27 is formed on at least one side.
As shown in a development view of FIG. 3A, the claw 27 is provided so as to be bendable by a method such as punching and forming integrally with the sealing plate 26, and when the liquid crystal display device 3 is clamped and fixed. In addition, the tip portion is the display area 34 of the liquid crystal display device.
Is not reached.

When the sealing plate 26 is formed by punching out of a metal plate, as shown in FIG.
It is preferable to form a shape having a concave portion 26a for forming a space 29 for accommodating the inside thereof and to form the claw 27 integrally. By forming the concave portion 26a, a convex portion 26b is formed around the sealing plate 26, and the convex portion 26b is bonded and fixed to the transparent substrate 21 with an adhesive 28. At this time, since the periphery of the sealing plate 26 is a convex portion 26b and the concave portion 26a is a flat surface, the mechanical strength of the sealing plate 26 is improved as compared with the case where the sealing plate 26 is a flat surface. Further, when a bent portion (not shown) is formed in the region of the concave portion 26a, or when a space 29 for accommodating the organic EL element 22 is formed by forming a further concave portion, the strength of the space 29 is further improved. , Which is preferable.

As described above, the nail 27 is formed on the side surface of the liquid crystal display device 3 with the organic EL backlight so as to extend from the sealing plate 26 of the organic EL backlight 2 to the side.
By bending the claws 27 and holding the liquid crystal display device 3 therebetween, the organic EL backlight 2 and the liquid crystal display device 3 can be fixed and aligned.

The claw 27 is for positioning and fixing from the side of the liquid crystal display device 3, so that it is necessary to provide at least one claw. When provided on at least three sides in a rectangular display device, the organic EL backlight 2 and the liquid crystal display device 3 can be fixed without causing a shift.

As in the liquid crystal display device 10 with an organic EL backlight shown in FIG. 5, a connection terminal 33 for the liquid crystal display device of the liquid crystal display device 3 is connected to a flexible printed circuit (FPC).
cuit), TCP (Tape Carrier Package), COF (Ch
Claws 27a may be provided on the sides of the liquid crystal display device terminal extraction portion 31a connected before fixing the flexible substrate 4 such as ip on flexible printed circuitry to the organic EL backlight 2. In this case, the size of the sealing plate 26 that covers the organic EL element 22 is increased, and the sealing plate 26 is attached so that the organic EL electrode terminals 23a and 25a are not provided at the bonding locations. As a result, fixing is performed more firmly and mounting is performed before mounting to a portable device or the like, so that it is not necessary to perform positioning or the like in a narrow device, and mounting work is improved. In addition, the displacement due to vibration after being attached to these devices can be reduced.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments will be described with reference to the drawings. Example 1 (Preparation of an organic EL backlight) As shown in FIGS. 3 and 4, an ITO transparent electrode 23, a TP
D hole transport layer (50 nm) and AlQ3 light emitting layer (50
nm) and an aluminum-lithium alloy cathode 25 (150 nm) were continuously deposited to form an organic EL element 22. Thereafter, under a dry nitrogen atmosphere, the organic EL element 22 is formed by a gap 29 between the stainless steel sealing plate 26 in which a concave portion 26 a provided with a desiccant exhibiting a chemical adsorption action (not shown) is formed and the glass substrate 21. The organic EL backlight 2 was sealed by adhering the peripheral projections 26b with an adhesive 28 made of an ultraviolet curable resin so as to be positioned inside. At this time, a stainless steel plate having a thickness of 1 mm was used as the sealing plate 26, and a plurality of claws 2 extending in the side direction with respect to three sides were used for the three sides.
7 was formed integrally by press molding. (Preparation of Liquid Crystal Display Device) A pair of glass substrates 31 and 32 are provided with ITO transparent electrodes that are patterned in stripes, and the transparent electrodes provided on the respective substrates are arranged so as to be orthogonal to each other while maintaining a predetermined gap. Then, the periphery thereof was bonded with a sealant, and STN liquid crystal molecules were injected into the inner gap to seal. A pair of deflecting plates (not shown) is provided outside the glass substrates 31 and 32 to provide a reflection type ST.
An N liquid crystal mode dot matrix liquid crystal display device 3 was produced. (Mounting of Liquid Crystal Display and Organic EL Backlight) As shown in FIGS. 1 and 2, after the nail 27 of the organic EL backlight 2 is bent at a substantially right angle to the light emitting surface 2b side,
The L backlights were superposed such that the light emitting surface 2b of the L backlight was on the liquid crystal display device 3 side. At this time, the liquid crystal display device 3 was brought into contact with the bent claws 27 to achieve alignment. Then, the liquid crystal display device 3 of the nail 27 of the organic EL backlight 2
The portion protruding in the thickness direction from was bent, and the liquid crystal display device 3 was sandwiched and fixed in the seal region 35 of the liquid crystal display device.

The liquid crystal display device 1 with the backlight thus produced has the organic EL backlight 2 and the liquid crystal display device 3 connected to each other, and can be easily attached to other information equipment in this state. Was completed. In addition, when a liquid crystal display device 3 was scanned and driven at a duty of, for example, 1/240 by connecting a flexible substrate (not shown), a favorable reflection type due to the high reflection characteristics of the cathode layer 25 of the organic EL backlight 2 was obtained. A display was obtained. When an external power supply was connected to the pair of organic EL electrode terminals 23a and 25a of the organic EL backlight 2, a transmissive display by backlight illumination was obtained by emission of the organic EL backlight 2.

Organic EL backlight 2 and liquid crystal display 3
Is integrated in the process before mounting it on the information equipment, and special extra parts for it are not required, so that the number of parts can be reduced and the installation space can be saved.

In the above-described embodiment, the liquid crystal display device 3 and the organic EL backlight 2 are directly superimposed. However, as shown in FIG. 6, a diffusion plate or a diffusible material is dispersed between the two. An intermediate layer 16 such as a resin layer may be provided. As the intermediate layer 16, a semi-transmissive film (RDF polarized light, manufactured by 3M) having different transmission polarization axes and reflection polarization axes.
When a reflective film is used, the backlight is OF
In the case of the reflective display set to F, the display is viewed as a normal reflective type, and in the case of the transmissive display with the backlight turned on, the display of the liquid crystal driving portion is obtained by the function of the film, in which the display of the liquid crystal drive portion is negative-positive. . 1/4 with the film
When a wave plate is inserted, the cathode layer 25 of the organic EL element is used.
Since the direction of the circularly polarized light by the reflection on the surface is reversed, the light emitted by the backlight can be more efficiently introduced into the liquid crystal display device 3, and a display approximately 1.5 times brighter can be obtained.

Although the above-described embodiment is a preferred specific example of the present invention, various technically preferable limitations are given. However, the scope of the present invention is not limited to these embodiments. 7, an example using a TFT liquid crystal display device, an example using a resin plate provided with a nail 27 having a tip portion 27a of a hook structure as shown in FIG. As shown in (1), various changes have been made, such as an example in which the front substrate 32 of the liquid crystal display device is formed smaller than the other substrate 31, and a stack 27 is disposed around the periphery to reduce the protrusion amount. The case is also included in the present invention.

[0029]

As described above, according to the present invention, the alignment and fixing between the organic EL backlight and the display device can be performed before the display device is mounted on a device such as a portable device. The assemblability can be improved. In addition, it is possible to provide a mounting method in which a space for mounting the display device with the organic EL backlight on information equipment or the like can be reduced, and connection performance is remarkably improved.

Further, since the backlight and the display device can be fixed and supplied with electric power in a simple manner, the number of components can be reduced, and the area occupied for fixing and connecting the display device with the backlight can be reduced. Thus, a display device with an organic EL backlight, which is reduced in size and weight can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an embodiment of a display device with a backlight according to the present invention.

FIG. 2 is an exploded perspective view for explaining a method of attaching the display device with the backlight in FIG. 1;

FIG. 3 is an explanatory view of the organic EL backlight of FIG. 1;
(A) is a plan view illustrating a sealing plate, and (b) is an organic E.
It is a rear view of L backlight.

FIG. 4 is an explanatory sectional view of the organic EL backlight of FIG. 3;
(A) is a sectional view of an AA section, and (b) is a sectional view of a BB section.

FIG. 5 is a perspective view showing another embodiment of the display device with the backlight according to the present invention.

FIG. 6 is a cross-sectional view showing a main part of another embodiment of the liquid crystal display device with a backlight according to the present invention.

FIG. 7 is a cross-sectional view showing a main part of still another embodiment of a liquid crystal display device with a backlight according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 display device with backlight 2 organic EL backlight 3 liquid crystal display device 4 flexible substrate 16 intermediate layer 21 transparent substrate 22 organic EL element 23 translucent electrode (anode) 24 organic EL layer 25 cathode layer 26 sealing plate 27 nail 28 Adhesive 29 Void 31, 32 Glass substrate 33 Connection terminal for liquid crystal display device 34 Display area 35 Seal area

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Satoru Sakai 1-3-1 Edanishi, Aoba-ku, Yokohama-shi, Kanagawa Pref. Stanley Electric Co., Ltd. F-term (reference) LA12 LA30 3K007 AB00 AB13 AB18 BB01 BB05 CA01 CA05 CB01 DA00 DB03 EB00 FA01 FA02 5G435 AA00 AA17 AA18 BB05 BB12 BB15 EE25 KK05 LL07

Claims (3)

[Claims] 1. An organic EL device comprising: a display device using a light-transmitting substrate; and an organic EL backlight that irradiates the display device from the back side through a light-transmitting organic EL element substrate.
In a display device with a backlight, the organic EL backlight includes an organic EL having at least a pair of electrodes and an organic light emitting layer on the organic EL element substrate.
A device is provided, and a sealing plate that covers the organic EL element is provided on the back side facing the organic EL element substrate. The sealing plate has claws at at least two places in a lateral direction. A display device with an organic EL backlight, wherein the display device is fixed with the display device sandwiched from the back side of the display device. 2. The organic EL back according to claim 1, wherein the sealing plate is made of a metal plate formed integrally with the nail, and the display device is fixed by bending the nail. Display with light. 3. The display device with an organic EL backlight according to claim 1, wherein the nail is made of a resin having a hook structure.