JPS6159388A - Display unit - 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 (Field of Industrial Application) The present invention relates to a 7-trix type display device for displaying characters, figures, images, etc. The present invention relates to a matrix type display device which has a high - and is capable of displaying with high brightness.

(Structure of a conventional example and its problems) A conventional high-contrast matrix type display device will be explained with reference to FIG. 1, taking as an example a device using an electroluminescent element in a light emitting part.

In the figure, on the second side of a glass substrate 1, there are a plurality of transparent electrodes 2 perpendicular to the plane of the paper, a first insulating layer 3, a light emitting layer 4 using an electroluminescent element, and a second insulating layer 5. After sequentially laminating the above, a black insulating layer 6 was further formed.Secondly, a plurality of back electrodes 7 made of aluminum were formed perpendicularly to the transparent electrode 2 described in 1. When attempting to obtain high contrast using the black insulating layer 6 as described above, there is a problem in that the luminance of the emitted light decreases by 20 to 60%.

In addition, in cathode ray tubes, the light transmittance on the display surface is between 20 and 6.
A 0% filter was installed to improve image contrast. Therefore, although the contrast can be improved by installing such a filter in a matrix type display device, there is still a problem in that the luminance of the emitted light is reduced.

(Object of the Invention) The present invention aims to eliminate the above-mentioned drawbacks and provides a matrix type display device that can obtain both high contrast and high brightness in a bright environment.

(Structure of the Invention) A display device in which a matrix-type display portion is formed on a transparent insulating substrate, in which a light-emitting layer is laminated with an insulating layer interposed between a plurality of mutually orthogonal transparent electrodes and a back electrode. In this method, at least two types of regions having different refractive indexes are formed in a transparent insulating substrate, and a plurality of columnar convex lenses arranged in parallel at the same pitch are formed on one electrode of the matrix display section. A columnar convex lens converges the light from the light emitter to obtain high brightness. Furthermore, the convergence effect is increased by forming the light emitter layer with a thin film electroluminescent element.

(Explanation of Examples) Embodiments of the present invention will be explained with reference to FIGS. 2 to 4.

In FIG. 2, the Rix type display device 71 has a plurality of transparent electrodes 9 parallel to the paper surface on a transparent insulating substrate 8 composed of a low refractive index region 8a and a high refractive index region 8b, First insulator layer 10, light emitter layer 11, second insulator layer 12
After these are sequentially laminated, a plurality of back electrodes 13 are formed so as to be orthogonal to the transparent electrode 9 described in 1.

Note that among the two regions constituting the above-mentioned transparent insulating substrate 8, the low refractive index region 8a is made of borosilicate glass with a refractive index of 1.47, and is made of columnar convex lenses parallel to the above-mentioned back electrode 13 at the same pitch. The high refractive index region 8b forming the refractive index 2
．． 00 rare element borate glass.

This transparent insulating substrate 8 is made by forming a plurality of striped grooves on the surface of a borosilicate glass substrate using photolithography, thermocompressing a rare element borate glass plate onto the grooves, and then grinding the surface. It is processed into a flat surface, and the pitch of the stripes is 20 μm.

The transparent electrodes 9 are formed by forming a tin-doped indium oxide film on the surface of the transparent insulating substrate 8 using a high frequency sputtering method, and then forming a spacing of 40 mm between the electrodes using photolithography.
It is a cotton-like electrode with a width of 160 μm and a width of 160 μm.

Further, a first insulating layer 10 mainly composed of strontium titanate with a thickness of 600 nm, a manganese-activated zinc sulfide luminescent layer 11 with a thickness of 400 nm, and a second insulating layer 12 consisting of yttrium oxide with a thickness of 1100 nm. , high refractive index region 8
The spacing between the parallel electrodes is 40 μm, which is the same as the cotton-like groove in b.
A back electrode 1 made of aluminum with a width of 160 μm
3 forms a thin film electroluminescent element.

By selectively applying an AC pulse voltage of 120 Vn-p to the electrodes 9 and 13 of the display device configured in this manner, the portion of the luminescent layer 11 sandwiched between the selected electrodes emits light. It was possible to display text, figures, and images.

FIGS. 3 and 4 show the results of investigating the relationships between environmental illuminance and contrast, and between applied voltage and brightness, respectively, for a display device according to the present invention and a display device using a conventional glass substrate.

In FIG. 3, the horizontal axis represents the illuminance of the environment where the display device is installed, and the vertical axis represents the contrast 1-, qualitatively using arbitrary scales. Curve A shows the display device according to the present invention, and curve B shows the conventional display device, showing that the contrast improves as the ambient illuminance becomes brighter.

FIG. 4 qualitatively shows the applied voltage VO-F on the horizontal axis and the emission brightness on the vertical axis using arbitrary scales. Curves A and B are similar to those in Figure 3, and the applied voltage is 100V.
When the brightness exceeds , it shows that the brightness of the display device of the present invention exhibits better performance than the conventional display device.

6- This is an environment in which the columnar lenses formed on the transparent insulating substrate 8 not only converge the light of the light emitting layer 11 and project it from the surface of the substrate 8, but also enter the light from the surface of the transparent insulating substrate 8. Light is diffused at the interface of the low, high refractive index region, and passes through the substrate 8.
This is thought to be due to the reduction of the reflection rate from the surface of the

In this example, the high refractive index region 8b is made of rare element borate glass, but even if the glass contains barium oxide, lead oxide, tantalum oxide, thorium oxide, zirconium oxide, etc. If the refractive index is greater than the low refractive index region, it can be used in the display device of the present invention.

In addition, in this example, rare element borate glass was adhered to the surface of the low refractive index region 8a in which the striped grooves were formed by thermocompression bonding, and then the surface was ground to form the high refractive index region 8b.
A display device according to the present invention was also obtained by bonding a high refractive index material such as lithium niobate or titania using the CVD method and then performing surface grinding in the same manner.

(Effects of the Invention) As explained above, according to the present invention, both high contrast and high brightness were obtained in a bright environment, and a remarkable effect was obtained in improving the performance of a 7-trix display device.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional matrix type display device;
The figure is a sectional view of a matrix type display device according to the present invention, and FIG. 3 is a characteristic diagram showing the relationship between environmental illuminance and contrast.
FIG. 4 is a characteristic diagram showing the relationship between applied voltage and brightness. 1...Glass substrate, 2,9...Transparent electrode, 3
．． DESCRIPTION OF SYMBOLS 10... 1st insulator layer, 4, 11... Luminous body layer, 5, 12... 2nd insulator layer, 6... Black insulator layer, 7, 13... Back electrode, 8a...Low refractive index region, 8b...High refractive index region, A...Characteristic curve according to the present invention, B...Characteristic curve of conventional example. Patent Applicant Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 2 a 44 reduction degree (Take, Kuwacho 1 Inkaro 噸噸行斤-(VO-P)

Claims (3)

[Claims] (1) In a display device in which a matrix display section is formed on a transparent insulating substrate, in which a luminescent layer is laminated with an insulator layer interposed between a plurality of mutually orthogonal transparent electrodes and a back electrode, At least two types of regions having different refractive indexes are formed in a transparent insulating substrate, and a plurality of columnar convex lenses arranged in parallel at the same pitch are formed on one electrode of the matrix display section. Display device. (2) The display device according to claim (1), wherein the matrix type display section is formed of a thin film electroluminescent element. (3) The high refractive index region within the transparent insulating substrate is made of rare earth element oxide, barium oxide, lead oxide, tantalum oxide,
The display device according to claim 1, wherein the display device is made of Gaussian material containing 10% or more of at least one of thorium oxide and zirconium oxide.