JPS5814183A - El display panel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention is an electroluminescent device.

In recent years, EL display panels in which an EL layer is sandwiched between dielectric layers have been developed and put into practical use. As a means of achieving lower voltage driving of the EL display panel, the dielectric layer is formed of a ferroelectric layer such as lead titanate (PbTi08), thereby substantially increasing the voltage applied to the EL layer. The method is being adopted.

The structure of this EL display panel generally uses an insulating substrate 1 made of a transparent glass plate as shown in FIG.
) are arranged in parallel, and the surface of the insulating substrate 1 including the surface of these front electrodes 2 is coated with PbTi, O
An EL layer 4 made of a strong EL material of zinc sulfide (ZnS:Mn) doped with manganese is formed through a first dielectric layer 8 made of A, and yttrium oxide (Y20B) is further formed on the EL layer 4. A linear back electrode 6 made of, for example, aluminum (Al) is arranged in parallel with orthogonal to the front electrode 2 via a second dielectric layer 5 made of the same material. Light from each intersection cell between the front electrode 2 and the back electrode 6 is observed from the insulating substrate 1 side.

By the way, the transparent glass plate used as the insulating substrate 1 of the EL display panel configured as described above is required to have a predetermined heat resistance and thermal expansion coefficient.

That is, when forming the PbTiO3 film that will become the first dielectric layer 8, high frequency sputtering is performed while the substrate temperature is maintained at about 600° C., so a heat-resistant transparent Galanic plate that does not deform at that temperature is required. Also ELM
After forming No. 4, the EL layer is heat-treated at about 580°C and subjected to cyanyl treatment, so the thermal expansion coefficient is 40 to 90 (XIQ-7) to prevent cracks in the EL layer at that time.
℃-1) is required. A special transparent glass plate having such a coefficient of thermal expansion and heat resistance is extremely expensive, and has been a major obstacle to reducing the price of EL display panels that are driven at low voltages.

The present invention has been made in view of the above-mentioned points, and its purpose is to provide an EL display panel that uses an inexpensive insulating substrate and can be driven at low voltage. An EL comprising an ELM provided between a front electrode having a predetermined shape and a back electrode placed oppositely on the front electrode, and a light emitting cell being defined in an area where the front electrode and the back electrode face each other.
On the display panel, 1! ? The J memory R substrate is constituted by a multilayer insulating substrate in which a glass layer is laminated on an alumina base, and the alumina base in the area corresponding to the light emitting cell is partially removed.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a top view of essential parts for explaining the structure of the EL display panel according to the present invention, and FIG.
It is an A' sectional view, and the same parts as in FIG. 1 are given the same reference numerals.

In both figures, a transparent front electrode 2 made of ITO is disposed on a multilayer insulating substrate 7, and the surface of the multilayer insulating substrate 7 including the front electrode 2 surface is coated with PbTi0d-(D first (Z
) Dielectric NJB, ZnS: An ELM 4 made of Mn and a second dielectric layer 5 made of Y2O3 are sequentially laminated, and a back electrode 6 made of Ad is further provided on the dielectric layer 51. The EL display panel of the present invention is different from the conventional EL display panel in that the light emitting cells are defined at the intersections of the opposing regions of the back electrode 6 and the front electrode 2, as follows. This is the point. That is, the multilayer insulating substrate 7 is used instead of using an expensive glass plate as the insulating substrate. This multilayer insulating substrate 7 has a glass layer 7a laminated on an alumina base 7b, and is called a craze-coated alumina substrate and is widely used as a substrate for hybrid integrated circuits.

Glaze-coated alumina substrates such as those with excellent heat resistance and thermal expansion coefficients of 40 to 90 (XIO"-7℃-1) are commercially available, and compared to glass plates with such characteristics, It can be obtained cheaply.

Therefore, in the present invention, the above-mentioned glaze-coated alumina substrate, which has extremely advantageous characteristics in manufacturing an EL display panel, is used as the multilayer insulating substrate 7. However, although the glass layer 7a of such a multilayer insulating substrate 7 is transparent, light from the alumina-based light emitting cells cannot be extracted from the substrate side. Therefore, the area 8 portion of the alumina base 7b corresponding to each light emitting cell is removed, and the removed area 8 is removed.
The light from each light emitting cell is extracted through the multilayer insulating substrate 7 and observed from the side of the multilayer insulating substrate 7. The portions of the alumina substrate 7b corresponding to the light emitting cells 8 can be easily and accurately removed by photolithography using, for example, a caustic soda solution as the etching solution.

Thus, by using the inexpensive multilayer insulating substrate 7 as an insulating substrate instead of an expensive glass plate, it is possible to easily manufacture an EL display panel that can be driven at a low voltage at a low cost without changing the conventional manufacturing process. This also contributes to improving the display contrast as an additional effect.

In the above embodiment, the first dielectric layer 8 is made of PbT108.
We have described the case where YgO is formed, but this is limited to YgO,
It may also be formed with other dielectric layers such as (, t7'cEL
Layer 4 is sandwiched between dielectric layers 8 and 5 and 7' (not limited to KL display panels, the same effect can be obtained even when applied to DC drive type EL display panels in which the EL layer is directly sandwiched between the front electrode and the back electrode). Furthermore, the method is not limited to the method of removing the alumina substrate in a one-to-one correspondence with each light-emitting cell as in the above-mentioned embodiment, but it is also possible to remove the alumina substrate in a region that corresponds commonly to a plurality of light-emitting cells. It is also possible to remove the alumina substrate.

As is clear from the above description, the present invention provides an EL layer between a front electrode of a predetermined shape disposed on an insulating substrate and a back electrode placed opposite to the front electrode ball, and provides an EL layer between the front electrode and the back surface. In an EL display panel in which a light emitting cell is defined in a region facing an electrode, the insulating substrate is composed of a multilayer insulating substrate in which a glass layer is laminated on an alumina base, and by removing the region of the alumina base corresponding to the light emitting cell. ,
The light emitted from the light emitting cell is taken out from the substrate side through the removed portion, and by using an inexpensive multilayer insulating substrate instead of the conventional expensive glass substrate, it is an EL device that can be driven at low voltage. This has the advantage that the display panel can be realized at low cost.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the main part for explaining the structure of a conventional EL display panel, FIG. 2 is a top view of the main part for explaining the structure of the KL display panel according to the present invention, and FIG. It is an AA' sectional view in a figure. 1: Insulating substrate, 2: Front electrode, 3.5: Dielectric layer, 6:
Back electrode, 7: multilayer insulating substrate, 7a mini glass, 7'b
; Alumina base; 8: Area where the alumina base was removed. Figure 1 Figure 21 Figure 3

Claims (1)

[Claims] An EL layer is provided between a front electrode of a predetermined shape disposed on an insulating substrate and a back electrode disposed opposite to the front electrode,
In the EL display panel formed by both light-emitting cells in the area facing the front electrode and the back electrode, the insulating substrate is constituted by a multilayer insulating substrate in which a glass layer is laminated on an alumina substrate, and the above-mentioned luminescence upper μ corresponds to An EL display panel characterized in that an alumina substrate in a region is partially removed.