JPH0261725B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a liquid crystal display device.

In a liquid crystal display device, for example, a flat type liquid crystal display device that displays television images, the so-called X-Y
Simple matrix method and switching MOS transistor (insulated gate field effect transistor)
An active matrix method with a built-in hold capacitor is generally known. Among these display devices, the latter active matrix method is superior in terms of gradations of displayed images and crosstalk. This type of active matrix type liquid crystal display device uses time division multiplex driving. This drive circuit has a configuration shown in FIG. 1, for example. In the figure, LC indicates each liquid crystal display section arranged in a matrix in the horizontal and vertical directions. One electrode of each of these liquid crystal display parts LC is set as a common electrode, for example, at a ground potential,
The other electrodes are independently derived as picture element electrodes. In the figure, 1 indicates a horizontal control circuit section including a horizontal shift register, buffer circuit input circuit, etc., and 2 indicates a vertical control circuit section including a vertical shift register, buffer circuit, etc. A display signal is applied to the control circuit section 1, and each liquid crystal display section is sequentially displayed by the switching MOS transistors. In addition, C is provided for each display section LC, for example, 1/6
It shows the capacitance for charge storage, ie, hold, during a field signal period of 0 seconds.

The present invention, in such an active matrix type liquid crystal display device, forms the liquid crystal display section and its driving circuit on a common substrate, thereby making the entire device compact and compact, and further extending the life of the liquid crystal display section. An object of the present invention is to provide a liquid crystal display device designed to achieve the following.

First, an example of applying the present invention to a reflective liquid crystal display device will be described with reference to FIGS. 2 and 3.

FIG. 2 is a schematic plan view of the device of the present invention, and FIG. 3 is an enlarged sectional view of a portion thereof. First, the schematic structure of the device of the present invention will be explained with reference to FIG. form. A liquid crystal display section E constituting each picture element is disposed in the center, and peripheral circuit sections S constituting the control circuits 1 and 2 described in FIG. 1 are disposed around it, for example, around the four circumferences.

For example, the substrate 11 has 100 crystal planes and has a specific resistance of 2.
It is made of a silicon semiconductor substrate of ~3 Ω·cm, and the transparent substrate 12 provided opposite thereto is made of, for example, quartz glass or float glass. A liquid crystal, for example a guest-host type liquid crystal 13, is sealed in the liquid-tight space formed between them. On the substrate 11, as shown in FIG. 3, a semiconductor circuit is provided which constitutes a control circuit for driving and controlling the liquid crystal display section and a drive circuit provided corresponding to each picture element. As mentioned above, the peripheral circuit section S that constitutes the control circuits 1 and 2 explained in FIG. They are arranged horizontally and vertically along the surface direction of the substrates 11 and 12, that is, in a matrix. On the side of the semiconductor substrate 11 where the liquid crystal 13 is arranged, N-type source and drain regions 14s and 14d, for example, are formed by ion implantation, diffusion, etc. corresponding to these display parts, and between these regions A gate insulating layer 15, such as a SiO ₂ layer, is formed on top of the gate insulating layer 15, and a gate electrode 16 is provided thereon to form the switching MOS transistor described in FIG. Furthermore, a conductive layer 17 is provided on the source region 14s and the drain region 14d, which are ohmicly connected to become a source electrode and a drain electrode, respectively, and also serve as a wiring portion from these. Further, a high concentration region 18 of the same conductivity type as the substrate 11 is provided on the surface of the substrate 11 adjacent to each of these MOSs, and on top of this is a thin dielectric material such as SiO ₂ formed at the same time as the gate insulating layer 15. layer 19 is formed;
A conductive layer 17 connected to the drain electrode of the MOS extends over this, and a first conductive layer 17 is connected to the high concentration region 18.
The capacitor C explained in the figure is configured. The conductive layer 17 is made of, for example, a low resistivity polycrystalline semiconductor layer, for example, an N-type polycrystalline silicon layer having the same conductivity type as the source, drain, and regions 14s and 14d, together with the conductive layer 20 such as wiring or electrodes in the peripheral circuit section S. can be formed. 21 is an insulating layer formed on the surface of the substrate 11, for example a thick SiO ₂ oxide layer. Further, an insulating layer 33 of phosphor glass or arsenic glass is formed on the entire surface including the conductive layers 17 and 20,
Windows are formed in predetermined parts on the conductive layers 17 and 20, and metal wiring is used to lead out terminals electrically connected to the conductive layers 17 and 20 or to connect the conductive layers 17 and 20 to each other. Layer e.g. Al
A layer 22 is formed in a predetermined pattern, and an insulating layer 23 made of so-called glass-flowed phosphor glass, polyimide resin, or the like is deposited on the layer 22 to smooth the surface. And this insulating layer 23
Above are electrodes for applying voltage to the liquid crystal 13, particularly the display section E, that is, the picture element electrodes 24 provided corresponding to each picture element, and the portion facing the peripheral circuit section S, in other words, other than the original display section. For example, a ring-shaped peripheral electrode 25 and a terminal portion 32 are arranged around the four circumferences of the liquid crystal 13. Each picture element electrode 24 has a conductive layer 1 below it, which becomes one electrode of a capacitor C, for example.
It is electrically connected to the gold layer wiring layer 22 connected to 7 through a window bored in the insulating layer 23. An alignment layer 26 that has been subjected to an alignment treatment to obtain an alignment effect of liquid crystal such as SiO ₂ over the entire surface of the electrodes 24 and 25 and the insulating layer 23 where these are not formed.
is completely covered.

On the other hand, on the inner surface of the transparent substrate 12, an electrode 27 having a light-shielding property is arranged opposite to the peripheral electrode 25 provided on the substrate 11 side, for example, an electrode in which a Cr layer and an Au layer are laminated, or an electrode in which a Ti layer and an Au layer are laminated. electrodes are formed. On this electrode 27, an alignment layer 28 made of SiO ₂ or the like is formed and similarly subjected to an alignment treatment to obtain the alignment effect of the liquid crystal. Further, on the inner surface of the portion of the transparent substrate 12 constituting the display section E, a transparent electrode, such as a SnO ₂ or TiO ₃ layer, which serves as a common counter electrode 29 for each picture element electrode 24 is deposited. This counter electrode 29 is electrically connected to the light-shielding electrode 27 through, for example, a window formed in the alignment layer 28, so that, for example, a ground potential is supplied thereto. Further, the surface of the counter electrode 29 is also subjected to alignment treatment to obtain a liquid crystal alignment effect.

30 is a spacer that regulates the distance between the substrate 11 and the transparent substrate 12 to regulate the thickness of the space where the liquid crystal 13 is sealed, and a barrier that keeps the space where the liquid crystal is sealed liquid-tight; and 31 is made of Ag paste, In bumps, etc. For example, the light-shielding electrode 27 and the corresponding terminal portion 32 are electrically connected using a conductor.

An electrode layer 53, such as a Ti layer with a thickness of 300 Å and an Au layer with a thickness of 300 Å, is laminated and deposited on the back surface of the substrate 11, and is applied with, for example, a ground potential.

Particularly in the present invention, a ground potential that is the same as that of the light-shielding electrode 27 is applied to the peripheral electrode 25 so that the liquid crystal in the peripheral circuit section other than the display section of the liquid crystal 13 is brought into a state of no electric field.

A display device with such a configuration includes the control circuits 1 and 2 described in FIG.
Since they are formed integrally on a common substrate, it is possible to achieve compactness and compactness, as well as to simplify assembly and manufacturing, thereby facilitating mass production. Since the same potential is applied to the peripheral electrode 25 and the light-shielding electrode 27 that face each other, no electric field is applied to these parts, and this prevents fatigue of the liquid crystal here. It is possible to avoid the inconvenience that deterioration of the characteristics of the liquid crystal due to fatigue extends to other original display parts.

In the above-described example, when the common counter electrode 29 in the liquid crystal display section E is also given a ground potential, the counter electrode 29 and the light-shielding electrode 27 are electrically separated and are connected to a terminal independently from the counter electrode 29. It goes without saying that a derivation will be made.

In the device of the present invention described above, a signal voltage corresponding to the video display signal is sequentially applied to the picture element electrode 24 of each picture element of the liquid crystal display section E by the drive control circuit provided on the substrate 11. An optical change is obtained by applying a predetermined voltage to the liquid crystal of each picture element in cooperation with the opposing electrode 29, and this is transmitted from the transparent substrate 12 side to the opposing electrode 29 made of a transparent electrode. The desired optical display can be obtained through observation.

In the above example, the present invention is applied to a reflective liquid crystal display device, but the present invention can also be applied to a transmissive liquid crystal display device. An example of this case will be explained with reference to FIG. FIG. 4 shows an enlarged cross-sectional view of essential parts of this transparent type liquid crystal display device, and parts corresponding to those in FIG. 3 are given the same reference numerals and redundant explanation will be omitted. That is, in this example as well, the substrate 11 and the transparent substrate 12 are provided facing each other as described above. A liquid crystal, for example, a nematic twist type liquid crystal 13, is arranged in the liquid-tight space formed between the two, and a liquid crystal display section E, which constitutes each picture element, is formed in the center, and the surrounding areas, for example, in the four circumferences, are arranged as shown in FIG. It constitutes the peripheral circuit section S that constitutes the control circuit sections 1 and 2 explained in .
Particularly in this example, the substrate 11 is made of a transparent substrate such as a sapphire substrate, and a semiconductor layer 41 is formed on the sapphire substrate 11 by, for example, epitaxial growth. Form a semiconductor circuit. That is, a peripheral circuit section S constituting the control circuits 1 and 2 explained in FIG. Correspondingly, drive circuits, ie, MOS and C, corresponding to each picture element explained in FIG. 1 are arranged.

In this example, the capacitance C is connected to a conductive layer 18 provided in the semiconductor layer 41, which is ohmicly connected to the drain region 14d of the MOS, with a thin insulating layer 19 formed on the N-type high concentration region in this example. The capacitance formed between the conductive layer 17 and the electrode layer 42 made of Ta, for example, which extends over the conductive layer 17 via the insulating layer 33 and is ohmicly connected to the high concentration region 18. The electrostatic capacitance formed between the electrode layer 42 and the electrode layer 42 is electrically connected to the drain region 14d by extending thereon through an insulating layer made of Ta ₂ O ₅ in which the Ta surface of the electrode layer 42 is oxidized. This is a case in which a capacitor is connected in parallel with a capacitor formed between the capacitor and the metal conductive layer 22 connected to the capacitor.

Also in this example, each picture element electrode 24
is made of a transparent electrode such as SnO ₂ or TiO ₃ .

Further, on the transparent substrate 12 side, a conductive layer 43 having a laminated structure of Cr layer-Au layer or Ti layer-Au layer is coated in a lattice or net shape so as to separate each picture element. wear it. This light-shielding conductive layer 43
is a light-shielding electrode 2 provided around the transparent substrate 12
7 and may be formed to be interconnected, ie, electrically connected to each other. The transparent counter electrode 29 is deposited within a lattice or mesh on which at least the light-shielding conductive layer 43 is not formed, and is made of an insulating layer 28 of SiO ₂ or the like as in the above-mentioned example.
The light shielding electrode 27 is connected to the light shielding electrode 27 through a window formed in the window.

On the back surface of the substrate 11, a light-shielding layer 45, for example, a black silicone resin, epoxy resin, black metal, or carbon layer, is adhered, and a window 44 is formed in a portion facing the grid or mesh portion of the light-shielding conductive layer 43. For example, a metal layer 47 of Al or the like is formed on one side edge of the metal layer 47 in direct contact with the back surface of the substrate 11 with a polycrystalline silicon layer 46 interposed therebetween. Alternatively, the light shielding layer 45 is made of these polycrystalline silicon layer 46 and metal layer 47.
It can also be constructed from a laminate of.

In this way, the light shielding layer 45 of the substrates 11 and 12
The lattices or meshes 43 and 43 are used as light transmitting parts, and these are used as picture element parts of the display part E, and each MOS is arranged in the light-shielded parts where the light-shielding layers 45 and 43 are arranged.

In the above, the light-shielding electrode 27 and the light-shielding conductive layer 4
3 can be constituted by a Cr layer or W layer having low light reflectance. In the peripheral area of the transparent substrate 12, an alignment mark for bonding with the substrate 11 can be formed by the cutout pattern of the light-shielding electrode 27, and in the vicinity of the scribe line of the transparent substrate 12, the light-shielding electrode 27 and the transparent By not forming the counter electrode 29, it is possible to prevent a short circuit with the substrate 11 due to these electrodes being turned over by scribing.

In such a configuration, a signal voltage corresponding to the video display signal is sequentially applied to the transparent picture element electrode 24 of each picture element of the liquid crystal display section E by the drive control circuit provided on the substrate 11 as in the above-mentioned example. A predetermined voltage is applied to the liquid crystal of each picture element by the cooperation of the counter electrode 29, which controls the optical rotation as well-known, and transmits the transmitted light from the substrate 11 or 12 side. Observation of the optical display is performed as a change.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a drive control circuit of a liquid crystal display device used for explaining the present invention, FIG. 2 is a schematic plan view of an example of a liquid crystal display device according to the present invention, and FIG. 3 is an enlarged cross-sectional view of the main parts thereof. 4 are enlarged sectional views of main parts of another example of the device of the present invention. 11 is a substrate, 12 is a transparent substrate, 13 is a liquid crystal, 2
4 is a liquid crystal electrode, 29 is a counter electrode, 27 and 25 are light shielding electrodes, and peripheral electrodes facing the light shielding electrodes.

Claims (1)

[Claims] 1. A semiconductor circuit is provided on the surface of a substrate or a substrate, a transparent plate is provided opposite to the side of the substrate having the semiconductor circuit, and the opposing portion of the transparent plate and the substrate is maintained liquid-tight. A liquid crystal is sealed in a liquid-tight space, and a plurality of pixel electrodes for applying voltage to the liquid crystal of the display section and their counter electrodes are provided on the substrate side and the transparent plate side, and the liquid crystals other than the display section are A liquid crystal display device comprising: a light-shielding electrode that applies substantially the same potential to the transparent plate and an electrode opposing the light-shielding electrode on the transparent plate side and the substrate side.