JPS62270990A - El 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] 3. Detailed description of the invention Industrial applications The present invention relates to an EL display device.

2. Description of the Related Art A sectional view of a panel portion of a conventional thin film EL display device is shown in FIG. In FIG. 4, 23 is a glass substrate, 24 is an ITO electrode on the data side, 25 is a first dielectric layer, 26 is an EL light emitting layer, 2 is a second dielectric layer, and 28 is an aluminum electrode on the scanning side. A block diagram of the drive circuit configuration is shown in FIG. In FIG. 5, 29 is an effective display area of the EL display panel, 30.degree. and 31 are drivers on the data side and scanning side, respectively, and 32 and 33 are logic circuits such as shift registers, respectively.

In the EL display device configured as shown in FIGS. 4 and 6, the data side logic circuit 32 selects a plurality of data side drivers 30 at the same time, and the scanning side logic circuit 33 selects the scanning side drivers 31 sequentially. Line-sequential writing drive is performed, and a matrix display is performed by causing the intersections of the scan-side electrodes 28 and the data-side electrodes 24 to emit or not emit light. In an EL display device that performs such a matrix display, it is of course impossible to emit light in an area where no matrix exists, and the area is visually different from the non-light emitting part of the effective display area. There isn't.

In recent years, with the aim of improving visibility and reducing fatigue during VDT work, negative displays, which have traditionally been the majority of
It is hoped that positive display (selected pixel does not emit light) will become a more common display method in the future, in place of positive display (selected pixel does not emit light). The phenomena that appear are described below.

FIG. 6 is a diagram in which the alphabets H and T are displayed in the upper left corner of the screen in positive display. Since each pixel at the upper end, lower end, left end, and right end of the effective display area 29 contacts the outside of the display area 34, it is easy to recognize the selected pixel that emits light in negative display. On the other hand, in the positive display, as shown in FIG. 6, the non-emitting selected pixels shown on the left side of H and above T cannot be recognized.

Problems to be Solved by the Invention When performing positive display with the above configuration, there is a problem in that non-emitting selected pixels at the top, bottom, left, and right ends of the effective display area are recognized as apparent missing characters. Ta. Furthermore, if an attempt is made to ensure a border area that always emits light within the effective display area in order to prevent this, there are problems such as a decrease in display capacity and a complicated configuration of the control system including the control circuit. In view of this, the present invention forms a part of the border made of the second display layer around the effective display area, and makes it emit light during positive display, thereby selecting whether or not the upper end, lower end, left end, and right end of the effective display area do not emit light. An object of the present invention is to provide an EL display device in which pixels can be clearly recognized.

Means for Solving the Problems The present invention provides a first display layer provided on a glass substrate with a scanning side electrode and a data side electrode that are perpendicular to each other and sandwiching a first EL light emitting layer, and an effective display layer of the first display layer. This is an EL display device in which a second display layer including electrodes facing each other with a second EL light emitting layer sandwiched therebetween is formed in an area adjacent to the periphery of the area.

According to the above-described configuration, the present invention causes the border region of the second display layer to emit light during positive display, and changes the appearance of non-emissive selected pixels at the upper end, lower end, left end, and right end of the effective display area adjacent to the border region. Prevents text from missing on the top and improves visibility.

Embodiment FIG. 1 shows a sectional view of a panel portion of an EL display device in an embodiment of the present invention. 1 is a glass substrate, and a first display layer 13 and a second display layer 14 are formed on this glass substrate.
Form each layer. 2 is the data side ITO electrode, 3 is the first
A dielectric layer, 4 is a first EL light emitting layer, 6 is a second dielectric layer, 6
is a scanning side ITO electrode, 7 is an insulating layer separating the first display layer and second display layer, 8 is an ITO electrode, 9 is a third dielectric layer, 1
0 is a second EL light emitting layer, 11 is a fourth dielectric layer, 12 is an aluminum electrode, 13 is a first display layer, and 14 is a second display layer. FIG. 2 is a block diagram showing the panel portion and drive circuit configuration of an EL display device in an embodiment of the present invention.

16 is an effective display area consisting of the first display layer, 16 is a border area consisting of the second display layer, and 17 and 18 are the respective first display areas.
Drivers are connected to the data side electrode and the scanning side electrode of the display layer, 19 and 20 are logic circuits such as shift registers, and 21 is a high-voltage AC pulse generating circuit that drives the border region 1e of the second EL layer. FIG. 3 is a display image in which the alphabets H and T are displayed in the upper left corner of the effective display area in the embodiment of the present invention.

The operation of the EL display device of this embodiment configured as shown in FIGS. 1 and 2 will be described below.

In the effective display area 16 consisting of the first display layer 13,
The data side logic circuit 19 simultaneously selects a plurality of data side drivers 17, and the scanning side logic circuit 2° selects the scanning side drivers 18.
A line-sequential writing drive is performed to select the data-side electrode 6 and the data-side electrode 2, and the intersection point where the scanning side electrode 6 and the data side electrode 2 intersect is made to emit or not emit light, thereby performing a mask display. In the border region 16 consisting of the second display layer 14, the aluminum electrode 1
2 to the high voltage AC pulse generation circuit 21 and the ITO electrode 8
A high voltage alternating current pulse is applied between the border region 16 and the border region 16 to emit light. In the embodiment, the ITO electrode 8 is fixed at ground potential to prevent high-voltage AC pulses generated in the second display layer from being guided to the first display layer.

Since the driving of this border area is independent of the driving of the first display layer, both layers are driven without being restricted by each other.

Further, the shape of the counter electrode composed of the ITO electrode 8 and the aluminum electrode 12 is as follows: the effective display area 15 and the border area 1.
The aluminum electrode 12 is used as an X-direction electrode, and the ITO electrode 8 is used as a Y-direction electrode so that the electrodes 6 and 6 cannot be distinguished from each other.

As described above, according to this embodiment, the effective display area 16 is formed in the first display layer 13 and the border area 16 that emits light during positive display is formed in the second display layer 14. Non-emitting selected pixels at the upper end, lower end, left end, and right end of the effective display area 16 can be clearly recognized without reducing the display capacity. In the embodiment, the shape of the counter electrode of the second display layer 14 is the same as that of the matrix of the effective display area 16, but the average brightness of the border area 16 is equal to the average brightness of the effective display area 15 when the entire surface is emitted. Once set, the shape of the electrode may be a solid electrode modeled after the shape of the border region 16, and there are no particular restrictions.

As described in detail, according to the present invention, the border area of the second display layer emits light during positive display, and the non-emissive areas at the upper, lower, left, and right ends of the effective display area adjacent to the border area emit light. It is possible to prevent apparent missing characters in selected pixels and improve visibility, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a panel portion of an EL display device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the panel portion and drive circuit configuration of an EL display device according to the same embodiment, and FIG. 3 is a block diagram of the same embodiment. 4 is a cross-sectional view of a panel portion of a conventional EL display device, FIG. 5 is a block diagram showing the panel portion and drive circuit configuration of the device, and FIG. 6 is a diagram for explaining the effective display area and border area. The figure shows apparent missing characters that occur at the top, bottom, left, and right ends of the effective display area of the device. 16... Valid display area, 16... Border area, 17... Data side driver, 18...
. . . Scanning side driver, 21 . . . High voltage AC pulse generation circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3.
22----1-T4 page area 4rIII

Claims (1)

[Claims] a first display layer provided on a glass substrate with a scanning side electrode and a data side electrode that are orthogonal to each other and sandwiching the first EL light emitting layer;
A second display layer is formed in a region adjacent to the periphery of the effective display area of the first display layer, and includes electrodes facing each other with a second EL light emitting layer sandwiched therebetween, and causes the second display layer to emit light when performing positive display. An EL display device characterized by the following.