JPS5927915B2 - liquid crystal display device - Google Patents

Description

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

Conventionally, in XY matrix liquid crystal display devices in which groups of parallel conductors are arranged in the horizontal and vertical directions, and elements are sequentially selected at their intersections for display, the contrast of the screen decreases due to crosstalk, and the middle part of the image It had a serious drawback that it was difficult to display the scale and color. The present invention provides a flat liquid crystal display device that eliminates the influence of crosstalk and enables halftone display and color display.
The basic configuration of the present invention is shown in FIG. In FIG. 1, a first liquid crystal cell 1 has a structure as shown in FIG. That is, MBBA (MethoxyBen2ilidenp
, nButylAniline) to EBBA (Etho
xyBen2ilidenp, nButylAniln
The nematic liquid crystal 2 mixed with e) is surrounded by a spacer T between the glass substrate 4 on which the transparent flat electrode 3 of sno2 is attached and the glass substrate 6 on which the horizontal parallel bar-shaped transparent electrode 5 of sno2 is attached. I'm trapped. The second liquid crystal cell 14 shown in FIG. 1 has the same structure as that shown in FIG. 2, but includes a vertical parallel bar-shaped transparent electrode 16 instead of the horizontal parallel bar-shaped transparent electrode 5. In FIG. 1, light emitted from a light source 9 is converted into parallel light by a lens 10, and converted into linearly polarized light in a certain polarization direction by a polarizer 11. The light that has been linearly polarized by the polarizer 11 passes through the first liquid crystal cell 1 and reaches the first analyzer 12 . Since the polarization direction of the first analyzer 12 is arranged to be perpendicular to the polarizer 11,
The light that has passed through the liquid crystal cell 1 cannot pass through the first analyzer 12. Now, as shown in FIG. 3 among the horizontal parallel bar-shaped transparent electrodes 5 of the first liquid crystal cell 1, when a voltage is applied to the liquid crystal between one horizontal parallel bar-shaped transparent electrode 13 and the entire transparent electrode 3, the electric field strength increases. Linearly polarized light incident from the electrode surface at a certain angle and long axis of the molecule in accordance with Light arises. Further, by changing the voltage, the intensity of transmitted light of a specific wavelength can be controlled, and since the light source 9 is a white light source, light of a specific wavelength will be transmitted at a specific voltage. When the voltage reaches about 5 V in the dark and the voltage is further increased, the hue of the light passing through the first analyzer 12 changes in the order of gray → white → orange → red → blue → green. When voltage VR is now applied to the horizontal parallel bar-shaped transparent electrode 13, red light with a constant light intensity passes through the first analyzer 12 from the horizontal parallel bar-shaped transparent electrode 13 of the first liquid crystal cell 1.

This red light passes through the second liquid crystal cell 14 and reaches the second analyzer 15. The polarization direction of the second analyzer 15 is the first
Since the second liquid crystal cell 14 is arranged at right angles to the polarization direction of the analyzer 12, the red light that has passed through the second liquid crystal cell 14 cannot pass through the analyzer 15. Now, when a voltage VVR corresponding to the red signal of the color video signal is applied to the vertical parallel bar-shaped transparent electrode 16 of the second liquid crystal cell 14, with the aforementioned voltage of 5V as a reference to darkness, a red color with a luminous intensity corresponding to the red signal is applied. The light passes through the second analyzer 15 and reaches the screen 17. At this time, since liquid crystals generally have a slow response speed, 1H of the red signal is sampled and held, and line scanning is performed in which a voltage corresponding to the 1H signal is simultaneously applied to each of the vertical parallel bar-shaped transparent electrodes 16. At the time of the next line, voltage VB is applied to the horizontal parallel bar-shaped transparent electrode 18 as shown in FIG. of light is obtained through the first analyzer 12. At this time, this blue light is produced by applying a voltage VVB corresponding to the blue signal at this line to the vertical parallel bar-shaped transparent electrode 16 of the second liquid crystal cell 14, so that the luminous intensity is adjusted according to the blue signal at this line. The blue light passes through the second analyzer 15 and onto the screen 17.
reach. Furthermore, at the time of the next line, voltage VG is applied to the horizontal parallel bar-shaped transparent electrode 19, and green light with a constant light intensity is emitted from the horizontal parallel bar-shaped transparent electrode 19 of the first liquid crystal cell 1 to the first detection line. Obtained via photon 12.

At this time, a voltage VG corresponding to the green signal for this line is applied to the vertical parallel bar-shaped transparent electrode 16, and this green light is modulated according to the blue signal for this line and is projected onto the screen 17. . In addition, at the time of the next line, voltage VR is again applied to the horizontal parallel bar-shaped transparent electrode 20, and from this horizontal parallel bar-shaped transparent electrode 20 part of the first liquid crystal cell 1,
Also, red light with a constant light intensity is obtained via the first analyzer 12. At this time, a voltage VVR corresponding to the red signal at this line is applied to the vertical parallel column-shaped transparent electrode 16,
This red light is modulated and projected onto the screen 17 according to the red signal at this line. That is, for each - line, the horizontal parallel bar-shaped transparent electrodes 13 of the first liquid crystal cell 1
, 18, 19, 20, 21......... apply voltages R, VB, VG, R, VG...... in order, the first line is red, Blue light is obtained on the second line, green on the third line, red on the fourth line, etc. through the first analyzer 12.

Next, a voltage VVRl is applied to the vertical parallel bar-shaped transparent electrode 16 of the second liquid crystal cell 14, at the time of 1 line, a voltage VVR1 corresponding to the red signal at that line, and at the time of 2 lines, a voltage VVR1 corresponding to the blue signal at that line. When voltage VVB2 and 3 lines are applied, voltage VvG3 is applied according to the green signal for that line, and when 4 lines are applied, voltage VVR4 is applied according to the red signal for that line, and each color is applied according to the respective color video signals. The light is modulated and a color image is displayed on the screen 17. And in the next field, similarly - for each line, the first liquid crystal cell 1
horizontal parallel bar-shaped transparent electrodes 13, 18, 19, 20, 21
・・・・・・・・・Voltage B, VO, VR, VB...
...... is applied in order, the first line is blue, the second line is green, the third line is red, the fourth line is blue, etc.
The light of... is obtained through the first analyzer 12.

Next, at the time of one line, a voltage VVB is applied to the vertical parallel rod-shaped electrode 16 of the second liquid crystal cell 14 according to the blue signal at that line.
l.For 2 lines, voltage VVG2 corresponds to the green signal for that line; for 3 lines, voltage VVR3 corresponds to the red signal for that line; for 4 lines, voltage VVR3 corresponds to the blue signal for that line. By applying voltage VVB4, each color of light is modulated according to each color video signal, and a color video is displayed on the screen. Then, in the next field, voltages VG, VR, VB, VG, etc. are applied to the horizontal parallel bar-shaped transparent electrodes 13, 18, 19, 20, 21, etc. for each line. .
At line time, voltage V according to the red signal at that line time
At the time of VR2 and 3 lines, a voltage VVB3 corresponding to the blue signal for that line is applied, and at the time of 4 lines, a voltage VVO4 corresponding to the green signal for that line is applied, and a color image is also displayed on the screen 17. . This scanning is repeated to display a color image. Next, a signal processing method necessary to carry out the above-described scanning method of the present invention will be explained with reference to FIG.

The color video signal applied through the terminal 22 is applied to a sync separation circuit 23 to obtain a horizontal sync signal (H signal) and a vertical sync signal (signal). These synchronization signals are applied to a counter circuit 24 to obtain a color selection control signal. This color selection control signal is applied to the color selection voltage conversion circuit 25 to obtain color selection voltages R, VB, and VG, and these voltages are applied to each horizontal parallel bar-shaped transparent electrode 5 as described above. One terminal 22
The color video signal is processed by the well-known color video signal processing circuit 2.
6 to obtain a color signal (R.B.G signal). These color signals and the color selection control signal obtained from the counter circuit 24 are added to the color signal selection circuit 27, and the horizontal parallel bar-shaped transparent electrode 5
A color signal (R signal, B signal, or G signal) synchronized with the color selection voltage applied to is obtained. That is, since this color signal is delayed by one line time in the sample and hold circuit 28, when the voltage applied to the horizontal parallel bar-shaped transparent electrode 5 is 8, the color signal selection circuit 2
7 to select the B signal. Hereinafter, when the voltages applied to the horizontal parallel bar-shaped transparent electrodes 5 are VB and O, the color signal selection circuit 27 selects the G signal and the R signal, respectively. This selected color signal is applied to a sample and hold circuit 28. In addition, the horizontal synchronization signal obtained from the synchronization separation circuit 23 (
H signal) is applied to a sample pulse generation circuit 29 to obtain a sampling pulse. This sampling pulse is also applied to the sample and hold circuit 28 to sample and hold the selected color signal. At this time, the signal between one line of the selected color signal is sampled and held, and the drive circuit 30 synchronizes the voltage corresponding to the signal for one line with the color selection voltage applied to the horizontal parallel bar-shaped transparent electrode 5. Then, it is added to the vertical parallel bar-shaped transparent electrode 16. That is, for example, when a color selection voltage VR is applied to the horizontal parallel bar-shaped transparent electrode 5, a voltage VR corresponding to one line of sampled red signal is applied to the vertical parallel bar-shaped transparent electrode 16. What has been explained above is that both the first liquid crystal cell 1 and the second liquid crystal cell 14 are
This uses the Olled Birefrigence (ECB) effect, but as another configuration, the first liquid crystal cell 1
is the ECB effect, and the second liquid crystal cell 14 is the Dyrlami effect.
There is a method using the cScatterirg (DS) effect.

In this case, the second analyzer 15 becomes unnecessary with the configuration shown in FIG. In addition, as another arrangement of the present invention, in the arrangement shown in FIG. It is obvious that they may be arranged interchangeably.

At this time, the second liquid crystal cell DS effect is used (if the polarizer 1
0 becomes unnecessary. As described above, by displaying images using the liquid crystal of the present invention, crosstalk, which is the biggest problem, can be completely eliminated, and halftone display can also be performed without problems.

Furthermore, it is of course possible to display color images, and provides a liquid crystal display device that is superior to any conventional device.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the basic structure of a liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a perspective view showing the structure of a liquid crystal cell, and FIG. 3 is a perspective view showing the horizontal parallel bar-shaped transparent electrode 5 and the colors applied FIG. 3 is a diagram showing the relationship between selection voltages. 1...First liquid crystal cell, 14...Second liquid crystal cell, 11...Polarizer, 12, 15...
...Analyzer.

Claims (1)

[Claims] 1. A white surface light source, a polarizer, a first liquid crystal cell having a plurality of first parallel bar-shaped transparent electrodes, an analyzer, and a color of light passing through the analyzer, Means for applying a color selection voltage to the first parallel bar-shaped transparent electrode such that the color selection voltage is sequentially changed for each line to perform vertical scanning, and the color of the light in the same line is also sequentially changed for each vertical scan. and a second liquid crystal cell having a plurality of second parallel bar-shaped transparent electrodes perpendicular to the first parallel bar-shaped transparent electrodes of the first liquid crystal cell, into which the light passing through the analyzer is incident; Means for applying a voltage corresponding to the color signal to the second parallel bar-shaped transparent electrode to modulate the brightness so as to modulate the color signal in synchronization with the color of light selected by the means for applying the color selection voltage. A liquid crystal display device having: 2 The color of the light passing through the analyzer is R, B, G for each line.
The liquid crystal display device according to claim 1, characterized in that the liquid crystal display device changes between.