JPS58106595A - Scale display signal waveform - 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] The present invention relates to gradation display of a liquid crystal display device.

Conventional examples of gradation display using liquid crystal display devices include those using elements with non-linear characteristics, such as TPT (thin film transistor) and MOS transistors formed on a silicon substrate, or The gradation display was achieved by modifying the multiplex drive signal.

The processes for manufacturing transistors (TPT and MOS) are quite similar, but both require long processes and a large number of laminated layers. In addition, since it forms a transistor, the structure is complex, and wire breaks are likely to occur at points where signal lines, etc. intersect.
Furthermore, the destruction of the gate oxide film appears as a defect on the screen of the liquid crystal panel.

FIG. 1 is a cross-sectional view of the vicinity of a MO3 type transistor formed in a pixel using a silicon substrate. If we consider the process in this case, focusing on the photo process, we will see the following.

(1) Buttering the stopper 11 (2) Turning the bottom layer 5102 insulating film 12 (
3) Buttering the polysilicon layer 16 (4) Buttering the 5in2 insulating film 14 between the polysilicon layer 13 and the At layer 15 (5) Buttering the aluminum layer 15 (6) Buttering the aluminum layer 15 and the upper aluminum layer 16 S i between
Buttering of O2 insulating film 16 (7) - Upper aluminum layer 1
There was about 7T of 6 patterning, and the number of laminated layers was 6. In this way, when there are many processes using 7-otolithography, defects such as pattern defects introduced by photolithography become very large.

In other words, the yield from one photo process is A(0<A
<1), and if the number of photo steps is n, the yield in the entire process is A''.In the previous example, there are 7 steps, so the yield is likely to be very small.

FIG. 2 shows driving waveforms when performing gradation display using a conventional multiplex liquid crystal display device.

It can be seen that when the data signal 24 is applied to the selection signal 23, a voltage shown at 25 is applied to each pixel. The gradation is achieved by changing the pulse width of the data signal. This type of display device requires external memory, and in the case of TVs, it converts analog signals to digital.
The signal must be modulated into a pulse width and applied to the liquid crystal panel.

The present invention eliminates the above-mentioned drawbacks; the process is short, it can be driven at low voltage, the yield is good, and the structure is simple, so it is resistant to rubbing when making panels, and it is resistant to external damage. It also does not require memory.

FIG. 3 is an equivalent circuit diagram of the present invention, and FIG. 4 is an equivalent circuit diagram of the present invention.
This is an example of a signal waveform when a gradation signal is input to each pixel as shown in the figure. (α) is a waveform applied to the signal line 31, and (b) is a waveform applied to the signal line 35. The signal applied to the pixel 33 is injected from the signal line 51 in the section 411,
In the section 412, from the signal line 35 to the diode 34
injected through. (c) shows the change in the signal at the pixel and the voltage applied to the liquid crystal layer. By performing such driving, it is possible to construct an efficient panel that applies a large voltage to the liquid crystal even at a low voltage. In the case of gradation display, a voltage level 416 for the selection period is added, which has an intermediate value between the voltages of the OFF waveform 42 and the ON waveform 41. Similarly, in the case of (1,), the voltage waveform 414 corresponding to the intermediate tone of the gradation display has an intermediate value between the voltages of the OFF waveform 47 and the ON waveform 46. When a signal corresponding to the intermediate tone of the gradation display is applied, the voltage waveform applied to the liquid crystal layer becomes 415.416, which is an intermediate value between the waveform 44 when OFF and the waveform 43 when ON.

FIG. 5 depicts an example of signals applied to the scan signal line and the data signal line when actually performing gradation display. A signal (a) is sent to the selection signal line, and a data signal whose signal changes depending on the gradation level as shown in (b) is sent to the data signal line. Therefore, the signal applied between the signal 1i131 and the NESA electrode on the opposite substrate becomes 54. As described above, by simply changing the voltage level of the data signal, it is possible to realize a low-voltage driven liquid crystal panel that is simple, has high yield, and is resistant to rubbing.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the vicinity of a MO8 type transistor formed in a pixel using a silicon substrate. FIG. 2 shows a conventional example in which gradation display is performed by adding signals with different pulse widths to a multiplex panel. FIG. 6 is an equivalent circuit diagram near a pixel according to the present invention. FIG. 4 is a conceptual diagram of signal waveforms applied to the signal lines and pixels in FIG. 3. FIG. 5 shows signal waveforms of actual signal lines (scan signal line and data signal line). 11...Stopper 12...Lowermost layer 8102 layer 13...Borinlicon layer 14...Insulating film 15 between the Borinlicon layer and aluminum layer Aluminum 16...5102 Insulating film 17...-Aluminum 21...Selected section signal 22...Non-selected section signal 23...Select Signal 24 on the signal line...Signal 25 on the data signal line...
- Signal applied to each pixel 31... Signal line '52... Diode 33... Transparent electrode 34... Diode 35... Signal line 41...Selection signal (when ON), -42...
...Selection signal (077 hours) 46... Voltage applied to the liquid crystal layer (when ON) 44... Voltage applied to the liquid crystal layer (077 hours) 45...・Signal 46 of signal line 31 when signal is applied to signal line 35...Selection signal (when ON) 47...Selection signal (at 077) 48...
・Voltage applied to the liquid crystal (when ON) 49...Voltage applied to the liquid crystal (at 077) 410...Signal line 3
Signal 411 on the signal line 35 when the signal is applied to 1... Signal positive section 412... Signal eclipse section 413... Voltage waveform 41 corresponding to the intermediate tone of the gradation display
4... 415... Voltage waveform applied to the liquid crystal layer when a voltage corresponding to the intermediate tone of gradation display is applied 416... 51... Waveform 52 at the time of selection on the selection signal line・・・
...Waveform 56 on the selection signal line when not selected...
・Signal waveform 54 on the data signal line... Signal waveform applied between the selection signal line and the data signal line // 7151 Figure 2 Figure 5

Claims (1)

[Claims] (1) At least two elements having diode characteristics are formed for each pixel on one of the upper and lower glass substrates that sandwich the liquid crystal, and at least one diode is arranged in the direction from the signal line to the pixel electrode. In the same pixel, at least one of the diodes and another diode has a structure in which the direction of the signal line from the pixel electrode is in the forward direction, and the opposing substrate has a forward direction. In an IJ display device, the row signal line side is called the selection signal, and the column signal line side is called the data signal. The signal is a gradation display signal waveform characterized in that gradation is displayed by changing the voltage value of the data signal in accordance with the gradation level.