JPS5817424A - Liquid crystal optical device - Google Patents

Abstract

PURPOSE:To improve high-speed response characteristics, by setting a liquid crystal molecular array to 360 degree torsion, as to a liquid crystal panel using an optically activated nematic liquid crystal which generates dielectric transition by low frequency. CONSTITUTION:An optically activated nematic liquid crystal composition whose torsion pitch is about 4mum is used, and the surfaces of the upper and lower substrates are orientation-treated in parallel with each other. In this case, when thickness of a liquid crystal layer is set to 3-5mum, the liquid crystal takes a 360 degree torsion structure. A molecular array a-1 and a-2 in this case are those which have been seen from the side and the upper direction, respectively, and 30-34 are patterns of the liquid crystal molecules. On both the upper and lower sides, 2 polarization plates crossing at right angles to each other are placed at 45 degrees with respect to the orientation direction of the substrate, and as a result of measurement of a response by applying a driving signal, a delay of start of transmission has annihilated entirely as compared with a conventional case, and a quick response has been shown.

Description

[Detailed description of the invention]

The present invention relates to a liquid crystal optical device atK, and more particularly to a liquid crystal optical device that uses an optically active nematic liquid crystal that undergoes dielectric relaxation at low frequencies and has a high-speed response characteristic. Regarding liquid crystal panels, driving methods, and applications of liquid crystal optical devices using optically active nematic liquid crystals that cause dielectric relaxation at low frequencies One of the present inventions described in detail in Section 7047 makes the effects of the above invention more effective by twisting the crystal molecular arrangement f: 560°. - Table 1 lists the nematic liquid crystal compositions used in the present invention that generate dielectric relaxation tubes at low frequencies. By adding an optically active substance 4-(4-hexyloxypensyloxy)-benzoic acid-d-2-octyl ester to this liquid crystal composition, an optically active nematic liquid crystal composition can be obtained. . A liquid crystal composition to which t-2.2 weight percent of the above optically active substance was added was referred to as [Liquid Crystal-1]. Generally, the dielectric constant of liquid crystal is different between the direction of the liquid crystal molecular axis and the direction perpendicular to this.
41 persons are represented on C. Further, the difference between C and C, ie, #, 1-11, is defined as dielectric anisotropy, and is expressed as Δ8. Δa>O and Δ8<O
l- are called positive and negative dielectric anisotropy, respectively. In the liquid crystal composition used in the present invention, ΔC changes greatly depending on the wave number, and at frequencies lower than the cross frequency (hereinafter abbreviated as fc), ΔC is 6 g)0. At frequencies higher than fe, Δresistance becomes <0. FIG. 1 shows the frequency characteristics of the dielectric anisotropy of [Liquid Crystal-1]. IffF is 130°C. The same wave number t-fe is lower than the crossing same wave number fc, the same wave number is higher than the same wave number '
(1-fh, and the corresponding dielectric anisotropic tubes are Δ#2 and Δξξ, respectively.) When an application is applied between the opposing electrodes of the signal tube of fh, the liquid crystal molecules are aligned parallel to the electric field direction, f
When a signal h is applied, a vertical alignment force is applied. FIG. 2 shows a cross-sectional view of a liquid crystal panel constituting the present invention. Liquid crystal layer It! , a substrate 2 comprising an electrode 4 and an electrode 5
The substrate 50 is sealed with a seal 6 at a distance of a thickness d shown by 9. the surface of the board,
It was treated with alignment treatment agents 10 and 11 and rubbed with absorbent cotton. Polarizing plates 8 and 7 are electrically distributed on both sides of the two substrates. Here, the dt liquid crystal layer thickness and naming will be used hereinafter. The alignment treatment agents 10 and 11 are epoxy silane resins, polyide resins, etc., but without using these treatment agents,
The present invention can be satisfied with just friction. Further, as a method of alignment treatment, silicon oxide may be vapor-deposited once obliquely to the substrate so that the liquid crystal molecules are aligned horizontally on the substrate surface. [Liquid Crystal-1] is an optically active nematic liquid crystal composition, and its liquid crystal molecular arrangement has a twisted structure.

The twist pitch of [Liquid Crystal-1] is approximately 4 gm at room temperature. In this specification, the twist pitch is defined as the cycle of one rotation. Furthermore, the twist direction of [Liquid Crystal-1] is clockwise from the back to the front. This is the optically active substance 4 used.
-(4-hexyloxypensyloxy)-benzoic acid-11-2-octyl ester has a left-handed twist structure. , [Liquid Crystal-1] has a twisted structure opposite to that of [Liquid Crystal-1]. In this specification, [Liquid Crystal-1] is used to describe t, but the present invention is effective regardless of whether the system is right-handed or left-handed. . FIGS. 3(a) and 3(b) show the orientation treatment direction of the present invention. 20, 21, 22.2! S is the friction direction, which is the orientation treatment direction. FIG. 3 shows the liquid crystal panel viewed from above. In Figure 5-), the friction direction is 2.
0 and 21 are in opposite directions. One side of the upper board and the lower board 20
, and the other in the direction of 21. Here, in correspondence with the explanation below, the friction direction is defined as 20 tube lower substrate 21t-upper substrate. s3 diagram (b) shows the upper and lower boards and 42
2 and 25. 24,
25°26.27 indicates the polarization direction of the polarizing plate. The polarization direction is arranged at a position of ±45@ with respect to the orientation direction as shown in the figure. By carrying out the above-mentioned special alignment treatment, a liquid crystal panel using a [Liquid Crystal-1] tube and having a liquid crystal layer thickness of about 45 to 481 mm was prepared, and the response was measured. FIG. 94 is a diagram schematically showing the arrangement structure of liquid crystal molecules at this time. As mentioned above, the inherent helical pitch of [Liquid Crystal-1] is approximately 4 μm. When this liquid crystal composition is subjected to the special orientation treatment shown in FIG. 3, it takes on a 340@ twisted structure for a liquid crystal layer thickness of 3 to 511 m. 1 for 1 to 3 μm
80@, 540@ twist at 5-7 pm. At a liquid crystal layer thickness of 4.5 to 4.8jm, it has a 360" twisted structure. At this time, the molecular arrangement gold collection 4yA (
a1)-(a2)*(b-1)*(b2)
K: Shown. Figures 4 (a-1) and (a-2) show the fifth
This is an arrangement corresponding to the orientation treatment shown in FIG. (a-1)
(IL-2) is observed from the side, and (IL-2) is observed from above. 2
There is friction in the direction indicated by 0.21. It is a model of 30-5aFi liquid crystal molecules, and the hour hand is oriented in the direction from 30 to 34. # is the tilt angle at the substrate surface. 30 and 54Fi, tilted in the same direction @
fm' Figures (b-1) and (1)-2) are shown in Figure 3 (
This is an arrangement corresponding to the orientation treatment of b). (b-1) is observed from the side, (b-23 is observed from above. 22. Friction is observed in the direction shown in 26. 40 ~
44 is a liquid crystal molecule, which is oriented clockwise from 40 to 44 as in (a). The difference from (IL) is that 40 and 44 are tilted in opposite directions. The difference in response characteristics between these two arrangements will be described later. The liquid crystal drive signal is shown in the SS diagram, and the signal shown in the diagram is repeated at the sampling period T1 as indicated by so. T2 denoted by 51 is the opening time, and RTS denoted by 52 is the closing signal. 7tfh signal shown as 53 between 〒2, T3
During this period, a signal 7'2:fe indicated by 54 is applied. ss
F! The voltage is +/-aV. This signal is applied between the opposing II electrodes. The fh signal causes light to pass through, that is, the aperture, and the fe signal causes light to pass through.
In other words, it shuts down. 70 shows the light transmission response characteristic 1 of the liquid crystal optical device of the present invention which has been subjected to the alignment treatment tm shown in FIG. The panel configuration is shown in Figure 2.The signal (a-2
87) The temperature applied between the opposing electrodes (S and 6) is 40°C, 1150KHz, ! @-2KH
It is 2. The horizontal axis shows time in seconds, and the vertical axis shows transmittance t percent. The transmittance was set to 11oo1 when only two polarizing plates were arranged in parallel. @7 FIG. 71 shows the case where the alignment treatment shown in FIG. 6 was performed. 60,451fl,
The upper and lower substrates are aligned in the direction of Kt, and are orthogonal to each other. 62.65Fi is the polarization direction of the polarizing plate,
They are orthogonal to each other, and furthermore, they are distributed parallel to or perpendicular to the force distribution processing direction. The response characteristics of 70 of the present invention, which differ from the present invention in the structure and driving conditions of the liquid crystal panel only in the above-mentioned orientation processing direction and arrangement of the polarizing plate, are as follows.
Compared to the conventional response of 71, the delay in the start of permeation shown in 72 and 73 completely disappears, resulting in a faster response. 7
4 friends 75Fi, maximum transmittance of 70 and 71 respectively. Although it transmits up to 75tj1004j, the transmittance of 74 of the present invention is slightly lowered. This is thought to be because the J5@ polarized light was incident on the liquid crystal molecules, causing a phase difference between the extraordinary light and the ordinary light. When the alignment treatment shown in Figure 4(b) is performed, the liquid crystal molecules are arranged as shown in Figures 4(b-1) and 4(b-1). In this case, since the tilt direction of the liquid crystal molecules on the substrate surface is opposite to the upper and lower substrates K, when one drive signal is applied and the operation is performed, the response is similar to that shown in Fig. 70 when stable. However, the method of voltage application, l1lI
! This results in unstable behavior due to changes in . However, in a stable state, there is no inferiority compared to the case of the 3rd@k) orientation treatment. As described above, the present invention provides a liquid crystal optical device using a nematic liquid crystal composition that is optically active and generates a dielectric relaxation tube at low frequency, and achieves a faster response by arranging the liquid crystal molecules fs60@twisted. This is an epoch-making product that achieves these characteristics. Next, an application example that makes use of the present invention will be described. Application Example 1> An application example in which the present invention is used as a micro-shutter array for optical writing/transmission. FIGS. 8 and 9 show the configuration of a liquid crystal panel. The liquid crystal panel has common signal electrodes 919 and 92.
0 glass substrate 917 and signal electrodes 9゛21 and 9
A glass substrate comprising 22. 918 and spacer 926, and polarizing plates 923 and '1 are placed on both sides of the glass substrate.
It consists of 24 meetings. The common signal number consists of a transparent electrode 919 and an optically opaque metal electrode 920, and the signal electrode 92
1 and 922 are 11 transparent poles. The light is modulated by the transparent portion 919 of the common II pole and the microshutter formed as the signal electrode. 2000 micro shutters were made in a straight line with a length of 20a* at a pitch of 100μm. The orientation treatment direction and the polarization direction of the polarizing plate were as shown in FIG. 5(a). The liquid crystal molecular arrangement contains a 360° twisted structure. As for the driving method, we prototyped a driving IC that could open and close the micro-shutter tube in response to time-series pixel data, and mounted it on the panel. Each drive IO has 50 output drivers, so for the 200011 micro-shutter, we installed 20 on each side of the panel, for a total of 40. The timing chart of various signal waveforms necessary for driving and the circuit block diagram to realize it are shown at t141.
This is shown in Figure 0 and Figure 11. 1ooted operation start reset signal, 1002Fi
Line start signal indicating the start of one line of data, 1
The oo3Fi data tube request clock sends 2000 pulses for 1 line in synchronization with the line start signal, and the data tube is picked up in synchronization with this clock. 1004 is the ninth shift clock for transferring data to the shift register of the liquid crystal driving IC, and 1005 is a latch pulse for latching all data immediately after data transfer is completed. 1006.1007.1 is the drive waveform applied to the ooaFi liquid crystal, 100B is the common electrode signal, the liquid crystal micro shutter opens when the 1006 ON signal is applied, and 100B is the common electrode signal.
Closes when the OFF signal of 7 is received. The ON signal and the common electrode signal are composed of a combination of a high frequency fl and a low frequency f-, and their phases are inverted from each other. oy
The y signal is a low frequency that is in phase with fL of the ON signal. Also O
The period of the high frequency fl among the 115 periods of the N signal is called the opening time, and the circuit configuration that realizes this is 4.2M.
A Hz reference clock 1010 is divided by a divider 1011 to create various waveforms. 1015 in 2 m5ec 1I1
A line start signal for the first period is created, and everything is synchronized using this signal. At step 1012, 2000 pulse tubes are counted, and at step 1020, a request clock is generated and outputted together with a line start signal to a time-series pixel signal generator 1024, which is an external device. The data sent from the Ilil fluorine generator 024 in synchronization with the request clock is distributed to the data pipe 1019 in order to be sent to the driving xO 1022 implemented in an interdigital manner. Determined by opening time meeting 1016, ON signal at 1017, 01
Create F7 signal and common electrode signal. 101!1 and latch pulse 1014 to create shift Glock, ONN signal FF
The driving IC 1 is also output to 22 along with the signal data. Further, the common electrode signal is SOVK converted by the output buffer 1018 and applied to the common electrode 1025. IQ21 receives the reset signal sent from external device 1024 and starts each part. This is the control section that applies the stop. Next, the block diagram of the internal circuit of the driving integrated circuit is shown in FIG.
It is transferred by the 0-bit shift register 1030 in synchronization with the shift clock 1035. On one side, 20 IC shift registers are connected in cascade, and data output from the data mount 1040 is transferred to the shift register of the adjacent driving IC. 10 on each side like this
When 2,000 bits of data have been transferred to both sides of the panel, it is latched into a 50-bit latch 1031 at the timing of a latch pulse 1057. 105
2, the ON signal 10! corresponds to the latched data.
Switch between i8 and OFF signal 10i9, then convert logic level t drive voltage 5OVK with next level conversion 1053 and JIO! It is output from the drive buffer of i4 to the signal electrode. The micro-shutter array was driven in the manner described above, and a high-speed light valve array of 2 msec per line was realized. <Application example 2> The above application example 10 microshutter array was kept at 40°C, 7112 msec, '1'21 (15 msec). Placed behind the micro-shutter array,
When I applied transmitted light to the selenium-tellurium photoreceptor and used a magnetic roll to develop toner, the image was formed according to the print signal.The photoreceptor was moved at a speed of 5-7. Seconds. In this way, a high-speed optical writing printer could be obtained. As mentioned above in the application examples, if used in accordance with the present invention, a liquid crystal optical device with high-speed response characteristics can be realized.
Very useful applications have become possible. Moreover, the inherent advantages of liquid crystal devices include low cost, large area,
The effect of low power consumption, etc. is very large because it continues to live as it is.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the frequency properties of dielectric anisotropy of the liquid crystal composition used in the present invention. FIG. 2 is a schematic diagram of the structure of the liquid crystal panel used in the present invention. FIG. 3 is a diagram showing the orientation process direction of the present invention. FIG. 4 is a t-diagram illustrating the alignment of liquid crystal molecules when the alignment treatment of the present invention is performed. FIG. 5 is a diagram of liquid crystal drive signals. FIG. 6 is a diagram showing the direction of conventional alignment processing. FIG. 7 is a diagram showing the light transmission response characteristics of the liquid crystal optical device. FIGS. 8 and 9 are diagrams showing a liquid crystal panel 1 according to an applied example of the present invention. FIG. 10, FIG. 11, and FIG. 12 are diagrams showing the block configuration of a liquid crystal optical device driving circuit according to an applied example of the present invention. 1...Liquid crystal layer, 2.3-...Substrate 4.5-...Electrode 7.8...Polarizing plate 20-25...Orientation processing direction or more Applicant Suwa Seikosha Co., Ltd. Agent Patent attorney Tsutomu Shi Mogami Figure 3 Figure 4 Figure 8 Figure 9 Centroid 1-]-1111 Figure 10

Claims (1)

[Claims] two substrates each having at least one electrode tube facing each other,
During this period, the crossing frequency at which the dielectric anisotropy becomes zero is 1 at room temperature.
In a liquid crystal panel that encapsulates a liquid crystal layer made of an optically active nematic liquid crystal composition with a frequency of 0.00 KHz or less and is provided with a pair of polarizing plates on both sides of the substrate, the surfaces of the two substrates are A horizontal alignment process is applied to horizontally align the long axes of the liquid crystal molecules on the two surfaces in parallel, and the alignment of the liquid crystal molecules is twisted by 360 degrees between the two upper and lower substrates. Liquid crystal optical device written in 1-s.