JPH03216996A - Image display device - Google Patents

Abstract

PURPOSE:To dispence with conventional scanning ICs added later, to save a part mounting process resulting in decrease in a manufacturing cost and miniaturization of an image display device on the whole by manufacturing picture elements and scanning circuits on the same substrate. CONSTITUTION:On a translucent substrate 10, a picture element part 29 of thin film EL elements, and a vertical scanning circuit 30 and horizontal scanning circuit 31 which drive the picture element parts 29 are formed in a monolithic state. As the vertical and horizontal scanning circuits 30, 31 for driving the parts 29 are mounted on the same translucent substrate 10 with the picture element parts 29, a miniaturized image display device can be realized comparing with the conventional case where scanning ICs have to be added afterwards. The vertical and horizontal scanning circuits 30, 31 both can be produced at the same time as the picture element parts 29 eliminating the conventional mounting process.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an image display device using a thin INIEL element. BACKGROUND TECHNOLOGY In recent years, an image display device 1 using a thin film EL element has been developed as a flat panel display having characteristics such as light weight, thinness, and low power consumption.
It is attracting a lot of attention because it can be used in fields that cannot be covered by tubes, for example, as image display devices for portable meters. Figure 4 shows the basic structure of the pixel section of an image display device using conventionally used thin IIEL elements. This is made by sequentially forming a transparent electrode 42 made of indium tin mixed crystal oxide (hereinafter referred to as ITO) on one surface of a glass substrate 41 using a DC sputtering device, and a transparent electrode 42 made using a high frequency sputtering device. A first dielectric layer 43 made of Si02, a light emitting layer 44 made of ZnSiMn manufactured using an electron beam evaporation method, a second dielectric layer 45 made of AQ203 manufactured using a high frequency sputtering device, and a second dielectric layer 45 made of AQ203 manufactured using an evaporation device. The transparent electrode 42 and the back electrode 46 are each formed using the manufactured Aρ. At this time, the transparent electrode 42 and the back electrode 46 are formed in a stripe shape using photolithography so as to intersect with each other. As shown in FIG. 5, a vertical scanning IC 48 and a horizontal scanning IC 49 are externally mounted on a pixel section 47 using a thin film EL element, thereby manufacturing an image display device.

Problems to be Solved by the Invention However, in the above conventional configuration, the vertical scanning IC 48
Also, since the horizontal scanning IC 49 is externally mounted outside the glass substrate 41, the image display device 1 becomes larger than the pixel section 47, and the manufacturing cost also increases. The present invention solves the above-mentioned problems, and aims to provide an image display device using a thin film EL element, which is small in size and has a reduced manufacturing cost. Means for Solving the Problems In order to solve the above problems, the present invention provides an image display device using a thin film EL element, in which a pixel portion formed by a monolithic thin JflEL element and the pixel are monolithically formed on the same light-transmitting substrate. This device includes a vertical scanning circuit and a horizontal scanning circuit for driving the parts. Effects According to the above configuration, since both scanning circuits for driving are manufactured on the same substrate, the area of the entire image display device can be made smaller compared to a case where the scanning circuit is externally attached to the outside of the substrate.
Additionally, since the mounting process can be omitted, manufacturing costs can be reduced. Embodiment An embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a plan view showing a circuit configuration diagram of an image display device according to an embodiment of the present invention, FIG. 2 is an enlarged plan view of a main part of the pixel section in FIG. 1, and FIG. This is a cross-sectional view of F. First, the configuration of the pixel section 29 and its manufacturing method will be explained. As shown in FIG. 3, low pressure CVD (Chel
Iical Vapor Deposition; hereinafter referred to as CVD. >>A polysilicon layer 14 with a thickness of about 0.2 μm is formed by the method. Then, using a photoresist as a mask, a transistor region is formed by plasma etching, and then thermal oxidation is performed to form a silicon oxide (Si0
2) Form layer 11. On top of this, a polysilicon layer 12 with a thickness of about 0.3 μm is formed by low-pressure CVD, and the polysilicon layer 12 is patterned by plasma etching using a photoresist as a mask.
A gate electrode and a gate signal layer 13 shown in FIG. 2 are formed. After this, using the 7-year-old resist as a mask, wet etching is performed to form a silicon oxide layer 11 on the channel region.
is buttered to form a gate oxide film. Next, using the photoresist as a mask, a P+
Alternatively, As+ ions are implanted into the polysilicon layer 14 to form a source region 14a and a drain region 14b, which are n+ regions.
A thin film transistor is formed by forming .
Then, on the transparent substrate 10, a thickness of 1
An SIO2 layer 16 of approximately μm thickness is formed, and a glabellar insulating layer having a source contact window and a train contact window is formed by reactive ion etching using a photoresist as a mask. Further, an Aρ-SL alloy film with a thickness of about 1 μm is formed on the transparent substrate 10 by DC bias sputtering, and a source electrode 17 and a drain electrode 18 are formed by wet etching using a photoresist as a mask. A signal line 19 and a bonding pad 20 shown in FIG. 1 are formed. Here, a silicon nitride layer with a thickness of about 0.3 μm is formed on the quartz substrate 10 by plasma CVD, and a pixel electrode window and a train contact window are formed by reactive ion etching using a photoresist as a mask. A second glabellar insulation J]ll21 is formed. Since an oxide film such as ITO is used as the pixel electrode 23, for example, Crt! is used to prevent the Aρ-St alloy of the drain t[i18 from being oxidized during the fabrication of the oxide film. Metals that are difficult to oxidize, such as I and Ni films, are sputtered to a thickness of 0.2 μm using high-frequency magnetron sputtering.
After forming the contact 1122 so as to cover the train electrode 18 by about m, a contact 1122 is formed by wet etching using a photoresist as a mask. After that, a thickness of 0.1 was obtained using the DC magnetron scattering method.
After forming an ITO film with a thickness of approximately μm, a pixel electrode 23 is formed by wet etching using a photoresist as a mask. Thereafter, in an EL process, the first dielectric layer 24 in S102, the light emitting layer 25 in ZnSiMn, and the A1
A second dielectric layer 26 made of A.203 and a back electrode 27 made of A.rho.S1 are formed. Finally, a protective film 28 made of silicon nitride is formed for moisture-proofing purposes using a plasma CVD apparatus, and a pixel portion 29 is formed as shown in FIG. In addition, CMOS (Com
plementary Metal OxideSen
A vertical scanning circuit 30 and a horizontal scanning circuit 31 are formed on a transparent substrate 10 by a process (conductor),
This creates a monolithic image display device using thin-film EL elements! Manufacture and dispatch. Note that in consideration of the withstand voltage of the thin film transistor of the pixel portion 29, it is desirable that the light emitting layer 25 emit light at a low threshold voltage, for example, about 30 cm. As in this embodiment, the light emitting layer 2
5. ZnS such as ZnSIMn, CaS or SrS
When using an inorganic thin-film EL element using materials such as MBE (Molecular beam epi
taxi) equipment and MOVPE (Metal
(nic vapor phase epitaxy) equipment can be used. With the above configuration, the driving vertical and horizontal scanning circuit 30
．． 31 is manufactured on the same transparent substrate 10 as the pixel section 29, it is possible to realize a smaller image display device compared to the conventional case where an external scanning IC is used. Scanning circuit 30. 31 can be manufactured at the same time as the pixel section 29, and the conventional mounting process can be omitted. In this embodiment, an n-type transistor into which P+ or As+ was ion-implanted was used as the thin film transistor of the pixel portion 29, but a P-type transistor into which B+ was ion-implanted may also be used. That is, the structures of the pixel section 29, the vertical scanning circuit 30, the horizontal scanning circuit 31, and the thin film transistors are not limited to the above embodiments. In this example, EL
In the process, two dielectric layers are used, but it is also possible to use only one layer, or aluminoquinoline《81h
yclroxy quinoline Alriinu
An organic thin IglEL element such as 1) may also be used.

That is, as long as the threshold voltage of the light emitting layer is about 30V, it goes without saying that there are no particular limitations on the structure or material of the thin film EL element. Effects of the Invention As described above, according to the image display device of the present invention, since the pixel portion and the scanning circuit are fabricated on the same substrate, there is no need to use an external scanning IC as in the conventional case. Therefore, the mounting process can be omitted and manufacturing costs can be reduced, and the overall size of the image display device 1 relative to the pixel portion can be reduced. can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the circuit configuration of a pixel display device according to an embodiment of the present invention, FIG. 2 is an enlarged plan view of essential parts of a pixel section of the image display device, and FIG. 3 is an E--E in FIG. 4 is a cross-sectional view of a main part of a pixel portion of a conventional image display device, and FIG. 5 is a plan view of the conventional image display device.

Claims (1)

[Claims] 1. Thin film E arranged in a matrix on a transparent substrate
a pixel portion formed by an L element and a thin film transistor;
A vertical scanning circuit and a horizontal scanning circuit are provided for driving the pixel section, and the vertical scanning circuit and the horizontal scanning circuit are formed in a step of forming a thin film transistor of the pixel section on the light-transmitting substrate. Image display device.