JPH0337291A - El lamp - Google Patents

Abstract

PURPOSE:To improve the light-emitting efficiency of an EL lamp at low costs by employing a specific binder in the lamp which has a light-emitting layer comprising phosphor particles bound together by a binder and electrodes on both sides of the light-emitting layer, in which at least one electrode on the front side of the light-emitting layer is light-transmitting and covered with a film to be air-tight on its outside. CONSTITUTION:An EL lamp which has a light-emitting layer comprising phosphor particles bound together with a binder and electrodes on both sides of the light-emitting layer, in which at least one electrode provided on the front side of the light-emitting layer is light-transmitting and covered with a film to be air-tight on its outside, wherein the binder is one comprising at least 50vol.% cyanoethylated pullulan, 5 to 35vol.% cyanoethylated polyvinyl alcohol, and cyanoethylated saccharose.

Description

[Detailed description of the invention] [Industrial application field]

The present invention places the light emitting layer between EL clamps that are hermetically closed with a skin film.

[Conventional techniques and theirs: t! M]

The EL clamp light emitting layer has phosphor particles bound together with a binder. Conventional EL clamps have the disadvantages of high manufacturing cost and low luminous efficiency. EL clamps have been developed that use a unique binder to bind phosphor particles with the aim of increasing light emission output. This EL clamp uses a mixture of cyanoethylated bullulan and cyanoethylated sucrose as a binder. This combination of binders is
It has disadvantages of poor adhesion and luminous efficiency. EL clamps have also been manufactured using cyanoethylated polyvinyl alcohol alone as a binder. However, this EL clamp has the drawback that it has a very poor dielectric loss tangent at high temperatures of 40° C. or higher and has a short lifespan. Furthermore, EL clamps using cyanoethylated bullulan alone as a binder have been used. This EL clamp can ensure a long life over a wide temperature range, but
It has the disadvantage of poor luminous efficiency. Furthermore, the low adhesion of cyanoethylated bullulan reduces the mass productivity of the EL clamp. The binder that binds the phosphor particles in the light-emitting layer has the following properties: ■ high dielectric constant, ■ small dielectric loss tangent, ■ low temperature dependence of dielectric loss tangent, ■ high dielectric breakdown voltage, ■ excellent adhesion, and ■ compatibility with organic solvents. Soluble properties are required. However, a binder that satisfies all these properties has not yet been developed. Cyanoethylated bulluran has excellent electrical properties at high temperatures, but has the drawbacks of poor adhesion, strict mass production conditions, and low work efficiency. Although cyanoethylated sucrose has excellent electrical properties and transparency, it has the disadvantage that it cannot be used alone as a binder because it is a sticky liquid. The inventors of the present invention have succeeded in achieving excellent properties that cannot be achieved with a single sialdin by creating a unique combination of multiple types of sialdin and specifying the amount of weiring of each sialdin. Therefore, an important object of the present invention is to provide an EL clamp that has excellent luminous efficiency and can be mass-produced simply, easily, and inexpensively.

[Means to solve conventional problems]

The EL clamp of the present invention has the following configuration to solve the conventional problems. Electrodes are provided on both sides of the EL clamp and the light emitting layer. The front electrode has translucency so that light from the light emitting layer can pass therethrough. The outside of the electrode is hermetically sealed with an outer skin film. The phosphor particles are combined with a binder to form a light-emitting layer. The binder contains three types: (1) cyanoethylated bullulan, (2) cyanoethylated polyvinyl alcohol, and (2) cyanoethylated sucrose. The amount of cyanethylated bullulan contained in the binder is adjusted to 5Qvol% or more. Further, the content of cyanoethylated polyvinyl alcohol contained in the binder is specified to be 5 to 35 vol%.

[effect]

Table 1 shows the EL clamp luminous efficiency of the present invention. This table shows how to adjust the frequency and voltage of the EL clamp dynamic power source to make the luminance of each EL clamp the same.
Adjusting the L clamp supply power. As shown in this table, the EL clamp of the present invention, 2.4c
It showed an extremely excellent luminous efficiency of d/W. This luminous efficiency was improved by 20% compared to the case where cyanoethylated bullulan was used alone as a binder. Table 1 also shows that a 9% higher luminous efficiency was achieved when compared with the EL clamp using a binder in which 10 vol% of cyanoethylated sucrose was mixed with cyanoethylated bullulan. However, in the EL clamp of the present invention, the binder contains ■ 60% cyanoethylated bulluran, ■ 20
vol% cyanoethylated sucrose, ■ 20vo
One containing 1% cyanoethylated polyvinyl alcohol was used. In the EL clamp and binder of Conventional Example 1, cyanoethylated bullulan was used alone. The EL lamp of Conventional Example 2 contains 90 vol% in the binder.
A mixture of cyanoethylated bullulan and 10 vol% cyanoethylated saccharose was used. In addition, the EL lamp of the present invention has the advantage that the binder has excellent adhesive properties and can be mass-produced simply, easily, efficiently, and inexpensively, although it exhibits excellent light emission characteristics.

[Preferred embodiment]

The present invention will be explained in detail below. However, the embodiments shown below are illustrative of EL lamps for embodying the technical idea of the present invention.
The material, shape, structure, and arrangement of the L lamp are not limited to the following structures. The EL lamp of the present invention is
Various changes may be made within the scope of the claims. An EL lamp is composed of a light-emitting layer, an insulating layer located on the back side of the light-emitting layer, an electrode sandwiching the light-emitting layer and the insulating layer, and an outer film that airtightly surrounds the entire layer. The light-emitting layer has phosphor particles uniformly dispersed in a binder. As the binder for binding the phosphor particles, a mixture of 60 vol% cyanoethylated bullulan, 20 vol% cyanoethylated polyvinyl alcohol, and 20 vol% cyanoethylated sucrose is used. Phosphor particles are mixed into a binder solution, dried, and then thermocompressed to produce a sheet-like material in which phosphor particles are dispersed in a high dielectric material. The content of cyanoethylated polyvinyl alcohol contained in the binder is adjusted to a range of 5 to 35 voi%. If the content of cyanoethylated polyvinyl alcohol is too high, the dielectric loss at high temperatures will increase, and if it is too low, the adhesiveness of the binder will decrease and the working efficiency will decrease. Furthermore, if the content of cyanoethylated polyvinyl alcohol is too high or too low, the luminous efficiency at high temperatures will decrease. The amount of cyanoethylated polyvinyl alcohol to be mixed is usually determined as described above, taking into account the dielectric loss tangent, work efficiency, and luminous efficiency! preferably 10 to 25 vol.
Adjusted to a range of %. The content of cyanoethylated bullulan is 50 vol.
% or more. If the content of cyanoethylated bullulan is too small, the electrical properties at high temperatures will deteriorate, while if it is too large, the adhesiveness will be reduced and the work efficiency will be reduced. The above-mentioned range is specified in consideration of high-temperature electrical characteristics and work efficiency. For the binder in which three types of sialdins are mixed, the mixing ratio of cyanoethylated saccharose is determined by the mixing ratio of cyanoethylated polyvinyl alcohol and cyanoethylated bullulan. Since cyanoethylated sucrose has excellent electrical properties and transparency, increasing the mixing ratio improves the luminescent properties. However, if the mixing ratio of cyanoethylated sucrose is too high, the adhesiveness of the binder will decrease, resulting in a decrease in work efficiency. Therefore, preferably, the mixing ratio of cyanoethylated sucrose is adjusted to a range of 10 to 20 vol%. An insulating layer is provided on the lower surface of the light emitting layer. The insulating layer is made of, for example, Y2O3, TiO2, AQ203, ZnO1BaT.
Ferroelectric materials such as i03, PbTio3.5rTi03,
A mixture of cyanoethylated polyvinyl alcohol and cyanoethylated bullulan is mixed into a high dielectric organic agent, and this is applied to the light emitting layer and cured. For the electrode located on the lower surface of the insulating layer, a film, foil, or thin plate of copper, aluminum, etc. is used. This is because this electrode is not required to have translucency. The electrode located on the phosphor screen, which is the upper surface of the light emitting layer, is required to have translucency because light passes therethrough. For the front electrode, a transparent synthetic resin film with a conductive film attached to the lower surface is used. PET or polystyrene film can be used as the transparent synthetic resin film. The conductive film includes, for example, In2O3, SnO2,5
b2o3 etc. can be used. Typically, an EL lamp has a water retaining film provided on the inner surface of the outer skin film. A nylon film or the like is used as the water-retaining film, and absorbs moisture that has passed through the outer skin film to prevent deterioration of the luminescent layer due to moisture. The nylon films are connected at their peripheries to form a closed space, and the electrode, the light emitting layer, and the insulating layer are hermetically housed within the closed space. The electrodes are connected to lead wires. The lead wires are insulated from each other, airtightly sandwiched between the outer skin films, and led to the outside. The outer skin film is a film such as trifluorochloroethylene film whose inner surface is coated with polyethylene.
The peripheral edge is heat-sealed by heating. When an alternating current electric field is applied to the EL clamp and electrodes configured in this manner, the phosphor in the light emitting layer emits electroluminescence.

Claims (1)

[Claims] Electrodes are provided on both sides of the light-emitting layer, at least the front electrode is translucent, the outside of the electrode is hermetically sealed with an outer film, and the phosphor particles are bound with a binder. In the EL lamp, the binder is (1) cyanoethylated bullulane, (2) cyanoethylated polyvinyl alcohol, and (3)
The content of cyanoethylated bullulan is 50 vol% or more, and the content of cyanoethylated polyvinyl alcohol is 5 to 5% by volume.
An EL lamp characterized by having 35 vol%.