JPS60230117A - Storage capacity incorporated type liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal display device which has a relatively high aperture rate by forming storage capacity in such a multilayered structure that a minus electrode side is sandwiched from both sides. CONSTITUTION:A transparent conductive film 4 for a picture element electrode is deposited selectively on an insulating substrate 1, an insulating film 3 with thickness corresponding to the capacity value of the storage capacity is deposited over the entire surface, and a counter electrode 9 extending from the gate line of the front stage is formed thereupon to form the storage capacity. Then, when a transistor TR element part 6 is formed successively, a conductive film 10 for connecting the conductive film 4 to the source terminal of the TR element is formed so as to cover the counter electrode 9 extending from the gate line of the front stage across a gate insulating film 5. Consequently, larger storage capacity is formed within the same area. Thus, the aperture rate of the picture element part is increased greatly and the bright, excellent liquid crystal display deivce is obtained.

Description

Detailed Description of the Invention The present invention provides a selection transistor and a storage capacity flt for each pixel.
- A method for increasing the storage capacity in a matrix device type liquid crystal image display device without drastically reducing the aperture ratio of pixels.

In a liquid crystal display device using a transistor array using a thin film, an image signal written by turning on the pixel selection transistor of each pixel is written by δN of the transistor, and after turning off the transistor, the image signal written is written in the next cycle. It is necessary to hold it until a new image signal is written. At this time, if there is not sufficient storage capacity between the pixel and the common potential or ground potential, there will be no capacity to hold the image signal, resulting in problems such as poor black-and-white contrast ratio in the entire image.

For this reason, when actually manufacturing a matrix type liquid crystal display device, it is common to create a storage capacity of several hundred fP to several PF between a pixel and a common potential or ground potential.

What is shown in Figure 1 is a plan view of a pixel section of a liquid crystal display device that incorporates a storage capacity formed between a conventional pixel and a gate region in the previous stage (which settles at ground potential when the pixel is driven). Similarly, FIG. 2 is a sectional view thereof. After selectively depositing a transparent conductive film 4C for pixel electrodes, e.g. ITOM, on the insulating substrate 1, an insulating film 8 (e.g. silicon oxide) having a thickness corresponding to the capacitance value of the storage capacitor is deposited on the entire surface, A counter electrode 9 extending from the previous gate line is formed thereon to form a storage capacitor, and then a transistor element section 6 is sequentially formed.

In a liquid crystal display device having this unique structure, the portion where the storage capacity is formed does not transmit light, and the aperture ratio is sacrificed in order to obtain a sufficient storage capacity.

SUMMARY OF THE INVENTION In order to eliminate these drawbacks, it is an object of the present invention to provide a liquid crystal display device having a structure capable of incorporating sufficient storage capacity without drastically reducing the aperture ratio.

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 8 is a plan view of a pixel portion of a liquid crystal display device showing one embodiment of the present invention, and FIG. 4 is a sectional view thereof as well. On the insulating substrate 1, a transparent conductive film 4 for pixel electrodes (for example, -TTO is selectively deposited, and then an insulating film 8C, for example, silicon oxide, having a thickness corresponding to the capacitance value of the storage capacitor) is deposited on the entire surface. A storage capacitor is created by forming a counter electrode 9 extending from the previous nogate line thereon, but when the transistor element section 6 is subsequently formed, the transparent conductive film 4 for pixel electrode and the transistor are formed. A conductive film 10 (e.g., At-5<]) for connecting the source terminal of the element is formed of a counter electrode 9 extending from the previous gate line across a t-gate insulating film or a thin film layer thereof. In a liquid crystal display device with such a structure, it is possible to create a larger storage capacity within the same planar area than in a conventional structure.For this reason, the aperture ratio of the pixel portion is It can be made relatively large and provides a bright and good quality liquid crystal display device as a whole.

Further, FIG. 5 is a plan view of a pixel portion of a liquid crystal display device showing another embodiment of the present invention, and FIG. 6 is a sectional view thereof as well. After sequentially forming each layer on the insulating substrate 1 in the same manner as shown in FIG. 4 to form the transistor element part 6, the glabella insulation M1
1 is deposited on the entire surface, and a light-shielding conductive film I2 is formed thereon. At this time, the light-shielding film 12i is selectively formed so as to overlap in plane the portion where the storage capacitor t' is formed. The light shielding film '12 is electrically connected to the gate line at the previous stage. In a liquid crystal display device having such a structure, although the process is somewhat more complicated than the structure of the liquid crystal display device according to an embodiment of the present invention shown in FIGS. 8 and 4, A larger storage capacity ft can be built in the same planar shape. Therefore, the aperture ratio of the pixel portion can be set sufficiently large, and the system as a whole provides a bright and good quality liquid crystal display device.

As described above, according to the present invention, it is possible to form a sufficient storage capacity with a smaller area, and as a result, it is possible to provide a liquid crystal display device a' with a relatively good aperture ratio.

[Brief explanation of drawings]

FIG. 1 is a plan view of a pixel section in a conventional liquid crystal display device with built-in storage capacity, and FIG. 2 is a sectional view thereof as well. FIG. 8 is a plan view of a pixel portion of a liquid crystal display device with a built-in storage capacity according to an embodiment of the present invention, and FIG. 4 is a sectional view thereof as well. Further, FIG. 5 shows the storage capacity R in another embodiment of the present invention.
FIG. 6 is a plan view of a pixel portion of a type of liquid crystal display device, and FIG. 6 is a sectional view thereof as well. 10. Insulating substrate 8°, insulating film 400 for storage capacitor, transparent conductive film 5 for pixel electrode. Gate insulating film 6°, transistor element 7. Gate line 8, drain bus 90. Counter electrode for storage capacitor 1019 Pixel electrode, conductive film for connecting source terminal 1111 Interlayer P3 green film 120. Light-shielding film and above Applicant: Seiko Electronics Industries Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A matrix layout liquid crystal display device with a built-in storage capacity, characterized in that the structure of the storage capacity is a multilayer structure in which one electrode is sandwiched between two electrodes from both sides. . (2) The storage capacity built-in liquid crystal display device according to claim 1, wherein the multilayer structure is composed of five or more laminated layers.