JPS6237351Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field This invention relates to an electroluminescent device, and specifically relates to an improvement in a sealing structure for sealing a plate-shaped light emitting element with a flexible outer film.

BACKGROUND TECHNOLOGY Electroluminescent devices (EL devices), which are widely used as backlights in liquid crystal displays for watches, calculators, and various measuring instruments, are generally of the type in which a light emitting element is covered with a flexible outer film. A conventional example thereof will be explained with reference to FIGS. 1 to 3. Reference numeral 1 denotes a strip-shaped light emitting element, and numerals 2 and 3 denote a pair of transparent outer films for sealing the light emitting element 1.
The light-emitting element 1 has a transparent electrode 5 made of Sno ₂ or the like, an electroluminescent layer 6 in which phosphor particles are dispersed, an insulating layer 7 made of BaTio ₃ or the like, and a back electrode 8 made of Al vapor deposition or the like, which are sequentially formed on one side of a transparent substrate 4. It is a layered product. Appropriate current collectors (not shown) are connected to the upper and lower electrodes 5 and 8.
External lead wires 9, 9 are led out through the
When an alternating current voltage is applied thereto, the electroluminescent layer 6 emits light. The outer films 2 and 3 are made of fluorine-based resin material and have a shape slightly larger than the light emitting element 1.
The light-emitting element 1 is sandwiched between the two in a sandwich-like manner, and the peripheral edges protruding from the four sides of the light-emitting element 1 are overlapped and sealed by hot pressing to hermetically seal the light-emitting element 1. Such an EL device is used as a backlight by disposing a liquid crystal display 10 thereon and illuminating the liquid crystal display 10 from the back side.

By the way, since the outer skin films 2 and 3 have a structure in which the light emitting element 1 is sealed by sealing the peripheral edges thereof,
In order to seal the light emitting element 1 sufficiently hermetically, the width of both peripheral sealing portions is required to be at least 1.5 to 2.0 mm. The peripheral sealing portions of the outer skin films 2 and 3 are
This is the non-emissive portion of the EL device, and in order to increase the effective light emitting surface of the EL device, it is desirable to make the peripheral sealing portion as small as possible, but there is a limit due to the width of 1.5 to 2.0 mm. Especially for an EL device used as a backlight for a small liquid crystal display 10,
If the width _d1 of the peripheral sealing parts m and m in the longitudinal direction of the outer skin films 2 and 3 is as much as 1.5 to 2.0 mm, the upper and lower parts of the liquid crystal display surface tend to become dark, which is a factor that greatly impairs the quality. Further, if the two outer films 2 and 3 have pinholes in areas other than the peripheral sealing portions, outside air may enter the interior through the pinholes, which may impair moisture resistance. To prevent this, the outer skin film 2,
3 is quite thick for this kind of film at 300 μm.
However, the effect of preventing deterioration of moisture resistance due to pinholes is not sufficient, and thicker outer films 2 and 3 are more difficult and expensive to manufacture than thin ones, which reduces the cost of EL equipment. This has become the biggest factor in raising prices.

Disclosure of the invention This invention was made in view of the above problems.
It has a structure in which a rectangular plate-shaped light emitting element is wrapped and sealed with two outer films that are folded in half.
Provides EL equipment.

The feature of this invention is to use the above-mentioned two outer films folded in half, to wrap the light emitting element from the two opposing sides, and to polymerize the overlapping parts of both films together using a heat press. This structure hermetically seals the light emitting element. In this way, the width of the non-emissive area created by the outer film along at least two sides of the light-emitting element in the direction in which the outer film is wrapped will be the thickness of one outer film, and the effective light emitting surface of the EL device will be significantly reduced. Expansion can be achieved. Furthermore, since the two outer skin films are almost entirely joined together to seal the inside, the influence of pinholes in the outer skin films can be ignored, making it possible to make the film thinner and significantly improving the sealing performance.

BEST MODE FOR CARRYING OUT THE INVENTION FIGS. 4 to 6 show examples in which the present invention is applied to the sealing structure of the rectangular plate-shaped light emitting element 1 shown in FIGS. 1 to 3 above, and are identical to each other. Reference numerals indicate the same content and details will be omitted. The following two outer skin films 11 and 11 are different from each other.
12, both films 11 and 12 are transparent films made of, for example, fluorine-based resin, and the first outer film 11 has a two-fold shape that only wraps the light emitting element 1 on its upper and lower surfaces and one end surface in the longitudinal direction. and the second
The outer skin film 12 has a two-fold shape that wraps the first outer skin film 11 surrounding the light emitting element 1 from the opposite direction. A thin layer of transparent adhesive 13, such as polyethylene, is applied to the outer surface of the first outer film 11 and the inner surface of the second outer film 12 in advance to ensure good and reliable adhesion between the two films 11, 12. It has become a habit.

With the lead wires 9 and 9 led out, the light emitting element 1 is first wrapped in the upper and lower surfaces and one end surface with the first outer film 11, and then the first outer film 11 is wrapped in the opening with the second outer film 12. Wrap from the end. The length of this second outer skin film 12 is sufficiently larger than the length in the longitudinal direction of the light emitting element 1, and when it wraps around the first outer skin film 11, both ends 12', 1
2' is made to stick out a little. Light emitting element 1
Press the inner surfaces of the bent portions of both films 11 and 12 against both end faces in the longitudinal direction of the films 11 and 12.
The two are overlapped on the upper and lower surfaces of the light emitting element 1, and the overlapped portions of the two are heat-pressed and integrated.
At the same time, the protruding ends 12', 12' of the second outer film 12 are also hot pressed to completely hermetically seal the light emitting element 1.

According to the above configuration, the width of the part from which the lead wires 9, 9 are drawn out and the part facing the lead wires in the film peripheral sealing part, which is the non-emission part of the EL device, is the same as before, but the width of the two parts in the longitudinal direction is the same as before. The width d ₂ of n and n is the same as the thickness of the outer skin films 11 and 12, respectively, and the thickness of the outer skin films 11 and 12 is made sufficiently thin to half or less than the conventional 300 μm for reasons described later. Therefore, the width _d2 can be significantly reduced, and the effective light emitting surface of the EL device can be greatly increased, making it effective as a backlight. Even if there is a pinhole in either of the films 11, 12, this pinhole will be sealed with the other film due to the almost entire bonding and integration of both films 11, 12, so the pinhole will not degrade the moisture resistance. There is almost no need to worry about the lower part, so both films 11 and 12
This makes it possible to use thin materials that are easy to manufacture and inexpensive.

It should be noted that the present invention is not limited to the above-mentioned embodiment. For example, as shown in FIG. It is also possible to easily commercialize a so-called EL device with a shield plate by interposing the shield plate 14.

As described above, according to the present invention, it is possible to improve the quality of a liquid crystal backlight by increasing the occupancy of the effective light emitting surface by reducing the size of the non-emitting part, and it is also possible to reduce the cost of the EL device by making the outer film thinner. Furthermore, by overlapping and sealing the two outer films on almost the entire surface, the airtightness is greatly improved, and a high-quality EL device with good moisture resistance can be provided.

[Brief explanation of drawings]

1 and 2 are a plan view and a front view of a conventional electroluminescent device, FIG. 3 is an enlarged sectional view taken along line A-A in FIG. 1, and FIG. 4 is an embodiment of the electroluminescent device of the present invention. FIG. 5 is an enlarged sectional view taken along the line B-B in FIG. 4, FIG. 6 is an exploded perspective view of FIG. 4, and FIG. 7 is a sectional view showing another embodiment of the present invention. . 1... Light emitting element, 11, 12... Outer film.

Claims (1)

[Scope of utility model registration request] An electroluminescent device characterized in that a plate-shaped light emitting element is folded in half and wrapped in two outer films from opposite directions, and the two outer films are overlapped and sealed.