JPS6169026A - Liquid crystal element - Google Patents

Abstract

PURPOSE:To measure the electrooptic characteristic of a liquid crystal element easily and accurately by forming shutter parts for test besides many minute arranged shutter parts. CONSTITUTION:Many segment electrodes S1 and S2 are formed and arranged on the inside face of a substrate 21 out of a pair of substrates 21 and 22 which are arranged to face each other, and band-shaped common electrodes C1 and C2 are formed a minute gap apart from each other on the inside face of the substrate 22 so that these common electrodes face segment electrode rows respectively, and shutter parts (a) where transmission of light is controlled are formed in parts where segment electrodes S1 and S2 and common electrodes C1 and C2 face each other. Segment electrodes St and St for test are formed on the outside of auxiliary segment electrodes S0 and S0, and shutter parts for test are formed in parts where segment electrodes St and St face common electrodes C1 and C2 on the substrate 22 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a liquid crystal device in which a large number of minute shutter portions are arranged.

[Technical background of the invention]

Recently, liquid crystal elements have been used for image display in television receivers and computer displays, and for optical writing in optical writing printers used as computer terminals and office equipment. .

Such optical writing printers print letters, numbers, figures, etc. at 240 dots per inch, or 100 dots per inch! am, which is extremely small.

However, the liquid crystal element used for image display, optical writing, etc. has a large number of minute shutter parts arranged at close intervals to control the transmission of light, and the shutter parts sandwich a liquid crystal layer. The shutter part is formed in an extremely small area corresponding to the dot to be written, and the shutter part is formed in an extremely small area corresponding to the dot to be written, and the shutter part is formed in an extremely small area corresponding to the dot to be written. An extremely large number of them are arranged according to their size. Since the multiple dots that make up characters, etc. must be written one dot line at a time for one page, the shutter section is operated at an extremely high speed (1 msec per shutter section).
is driven by.

Therefore, this liquid crystal element is required to have electro-optical characteristics such as excellent high-speed response characteristics, high contrast, and a large absolute transmitted view.

By the way, to determine whether a liquid crystal element for optical writing satisfies the electro-optical characteristics described above, it is determined by actually driving the liquid crystal element and using a measuring device to detect the light that passes through its shutter section. are being measured.

However, since the shutter part of such conventional liquid crystal elements is extremely small, the ratio (S/N ratio) between the light controlled by the liquid crystal element button and other leaked light is small, and accurate characteristics cannot be obtained. cannot be measured. In addition, it is extremely difficult to align the photodetection section of the measurement device and the shutter section of the liquid crystal element, and errors in photodetection due to alignment errors have a large effect, making it impossible to accurately measure electro-optical characteristics. There was a problem.

('Q BJJ Ol.) The present invention was made in view of the above-mentioned circumstances,
The purpose is to provide a liquid crystal element whose electro-optical characteristics can be easily and accurately measured.

[Summary of the invention]

In order to achieve the above-mentioned object, the main feature of the present invention is to form a test shutter section in addition to the many arrayed minute shutter sections, and use this test shutter section to display a liquid crystal display. This makes it possible to measure the electro-optical characteristics of elements.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings, taking as an example a liquid crystal element used for optical writing in an optical writing printer.

First, let me explain the configuration of an optical writing printer.
In FIG. 2, 1 is a photoconductive photosensitive drum, 2 is a band 1 device that uniformly divides the surface of the photosensitive drum 1, and 3 is an optical recording unit that performs optical writing on the surface of the photosensitive drum 10 that has been banded. This optical recording section 3 is driven by a recording control section 4 that controls the timing etc. based on recorded information such as a picture book, and irradiates light onto the surface of the photosensitive drum 10, thereby controlling the irradiated portion of the surface of the photosensitive drum 10. Optical writing is performed by erasing the electric charge.

The electrostatic latent image formed on the surface of the photosensitive drum by the optical writing trap of the optical recording section 3 is developed with toner by the developing device 5.

Further, the recording paper 6 is fed by a paper feed roll 7,
After being temporarily stopped by a standby roll 8, the toner image on the surface of the photosensitive drum is sent to a transfer section 9 in synchronization with the toner image on the surface of the photosensitive drum, and the toner image on the surface of the photosensitive drum is transferred onto the paper 6 at the transfer section 9. Ru. This paper 6 is separated by a separation unit 10.
The toner image is separated from the photosensitive drum 1 at a fixing device 11, and then sent out by a paper discharge roller 12.

Note that the photosensitive drum 1 on which the toner image has been transferred to the paper 6 is subjected to a cleaner 1 after the toner charge is neutralized by the static eliminator 13.
4, residual toner is cleaned, and surface charges are neutralized by an eraser 15.

As shown in FIG. 3, the optical recording section 3 includes a light source 16,
It consists of a liquid crystal element 20 for optical writing and an imaging lens 17, and is configured to irradiate light from a light source 16 onto the surface of the photosensitive drum via the liquid crystal element 20 and the imaging lens 17.

The liquid crystal element 20 is horizontally elongated along the axial direction of the photosensitive drum 1, and the liquid crystal element 20 has a large number of minute shutter parts arranged at close intervals along its length to control the transmission of light. It was formed.

That is, FIG. 1 and FIGS. 4 to 8 show the liquid crystal element 20, and here a GH type liquid crystal element is shown.

To explain the structure of this liquid crystal element 20, 21.22 in the figure
are a pair of upper and lower transparent substrates made of glass plates with a thickness of approximately Q, 7 sn, and the pair of transparent substrates 21 and 22 are the outer sealing material 23a of the oblong frame as shown in FIGS. 1 and 7. and 2 to both sides of this outer sealing material 23a.
They are bonded via a pair of mutually parallel inner sealing materials 23b, 23b, which are formed on the inner side with a distance d of about 100 mm from each other.

The distance e between the pair of inner sealing materials 23b123b is approximately 1 inch, and the length of the narrow gap between the inner sealing materials 23b123b is, for example, the maximum width of a liquid crystal element for a printer that records on B4 size paper. In some cases, it is said to be 249 ho. Further, both ends of the inner sealing materials 23b, 23b are connected to both side portions of the outer sealing material 23a, respectively.
A space 30.30 is defined between the substrates 21 and 22 by the inner seal members 23b, 23b and both sides of the outer seal member 23a. In addition, in Figure 1, 3
1.31 is an air hole for letting the air between the substrates 21.22 escape to the outside when the pair of substrates 21.22 is polymerized and bonded;
It is sealed with a sealing material 32.32 applied after adhesion. Therefore, in the spaces 30, 30, the substrates 21, 22
The air (clean air) left behind during bonding is sealed.

Further, a wide liquid crystal reservoir F surrounded by an outer sealing material 23a is formed at both ends of the narrow gap E between the inner sealing materials 23b, 23b, and communicating with the narrow width gap E. The narrow gap E between the substrates 21 and 22 and the liquid crystal reservoir F are filled with a liquid crystal composition 24 containing a dichroic dye. Note that 33 is a liquid crystal injection hole provided at one end of the outer sealing material 23a;
When the pair of substrates 21 and 22 are polymerized and bonded, the substrate 21
．． This liquid crystal injection hole 33, which also serves as an air hole for letting the air between 22 and 22 escape to the outside, is used to apply a sealing material 34 after the liquid crystal composition 24 is injected (injected using a vacuum injection method). It is sealed by

Further, one of the pair of substrates 21 and 22 is
1 (hereinafter referred to as segment substrate), the inner sealing materials 23b, 2
3b within the narrow gap E.

Over its entire length, a large number of substantially rectangular segment electrodes S1, Sl, ..., Sl with a side length of approximately 180 μm are provided.
, Sl, . Two strip-shaped common electrodes C1 and C2 each having a width of 3 mm are formed in parallel with a minute interval of about 30 μm.

This segment electrode 81. Sl,..., Sl, Sl,
. . . and the common electric signs C1, C2 are all transparent electrodes, and the segment electrodes Sl, S1. ..., S
Shutter parts a, a, which control the transmission of light at the parts where common electrodes C1, C2 face each other.
... is formed.

The two rows of segment electrodes S1, Sl,..., Sl,
Segment electrode S1 of one column among Sl,...
Sl, . . . are segment electrodes S2, Sl of the other column.
, .

The reason why each shutter section a% a1... is arranged in two rows with a 1/2 pitch shift is that the light that has passed through the shutter sections a, a, ... of one row is irradiated in a single row. Between the rows of irradiation points on the surface of the photosensitive drum, the shutter section a of the other row
This is to form an electrostatic image with high dot density on the surface of the photosensitive drum by irradiating it with light that has passed through a, . Note that this shutter section a%a1... is for a liquid crystal element for a printer that records on a maximum of B4 size paper, and 1174 pieces are arranged in one column, and the shutter section a of each column is
, a, . The distance between the centers of parts a, a,... is approximately 2
It is said to be 60am.

Also, segment polarization S1 of one column. Sl, . . . and segment electrodes S2, Sl, . . . in the other column are 1
/2 Adjacent ones with a pitch deviation are common connection electrodes that are almost circular with the segment electrodes 25.25,...
The segment electrode drive circuit connection leads 26, 26, . Thus segments of one column) [pole S
1, Sl,... and the segment electrodes S2, S of the other column
The reason why the drive circuit connection leads are individually connected to the segment electrodes 81, 81, ..., Sl, Sl, ... of each column is that the drive circuit This is because the number of connection leads becomes extremely large, making it difficult to route these leads.For this reason, in this liquid crystal element, segment electrodes S1, Sl,... in one column and segment electrodes in the other column are separated. S2, Sl, . . . are commonly connected, and a common electrode C1 is connected to each segment electrode column.
, C2 are arranged to face each other to time-divisionally drive the liquid crystal element.

viscosity, the segment electrodes 81, 81. ..., S
l, Sl,... and common connection electrodes 25.25,...
and the drive circuit connection leads 26, 26, . . . are integrally formed of a transparent conductive material such as indium oxide.

Also, in Figures 1 and 7, 27.27,...
. is a low-resistance metal film made of chromium, gold, etc. deposited on the common connection electrodes 25, 25, . . . and the drive circuit connection leads 26, 26, . .27,... are common connection electrodes 25.25,...
... Part and drive circuit connection lead 26.26, ...
This is provided to reduce the electrical resistance of the part.

Note that the drive circuit connection leads 26, 26, . . .
(a) which protrudes outward from the outer sealing material 23a)
The electric circuit connection leads 26, 26, . . . are covered with metal films 27, 27, .
,... drive circuit connection terminal portions 26a, 26a,...
Covered except for.

In addition, in FIGS. 5 and 8, 28.28 is a seven-layered portion a1a on the common electrodes C1 and C2, . . .
This metal film 2 is a low resistance metal film deposited except for
8.28 is provided to reduce the electrical resistance of the common electrodes C14F, C2 and to regulate the light transmission area of the shutter portions a, a, .

28a, 28a, . . . indicate light transmitting portions (portions where the transparent common electrodes CI, C2 are exposed) regulated by the metal films 28.28, and the light transmitting portions 28a, 28a, .
28a, - is the vertical and horizontal length 11, Jz (see Figure 7)
are each approximately 90 μm square.

Note that the segment electrodes Sl, Sl, ..., Sl,
The film thickness of Sl,... and common electrodes C1 and C2 is 20
0 to 300 A, metal film 27.27, ... and 28
．． The thickness of 28 is approximately 170 OA.

Reference numeral 29.29 is a liquid crystal alignment film formed on the inner surface of the side substrate 21.22, and the film thickness of this alignment film 29.29 is 200~200mm.
It is 400A.

In addition, in this embodiment, the shutter parts a, a, .
Each segment electrode S1, Sl,... forming...
Inner sealing material 2 is placed on both sides of the array part of Sl, Sl,...
3b and 23b are set to narrow the liquid crystal filling area in the segment electrode array portion.
..., Sl, Sl, ... lead 26.26, ...
・The common electrodes CI and C2 are also connected via the liquid crystal composition 24.
This is because a high-frequency current flows through the common electrodes CI and C2, promoting heat generation in the common electrodes CI and C2.As mentioned above, by narrowing the liquid crystal filling area, the segments are separated into poles S1, Sl,..., Sl, Sl.
,...'s leads 26, 26,... and the common electrode C1
If the liquid crystal composition is not interposed as much as possible in the portion where the common electrodes CI and C2 face each other, the heat generation of the common electrodes CI and C2 can be reduced. In addition, in this example, segment) K pole S1.81. ..., Sl, Sl,...
Since both sides of the liquid crystal filled part where the liquid crystals are arranged have a double wall structure consisting of an inner sealing material 23b and an outer sealing material 23a, fine dust, moisture, etc. cannot enter into the liquid crystal layer from the outside. can be completely prevented.

On the other hand, in FIG. 1, 5O1So is a horizontally long auxiliary segment' electrode formed on both ends of the array portion of the segment electrodes S1, Sl, . . . , Sl, Sl, . The electrode 5O1So faces the common electrodes CI and C2 of the common substrate 22 and forms a margin erasing shutter section. This margin erasing shutter section includes the two rows of shutter sections a, a, . . . used for optical writing.
By irradiating light onto both ends of the photosensitive drum (corresponding to the margins on both sides of the recording paper) that are not irradiated by the light that has passed through it, and erasing the electrical charges on both ends of the photosensitive drum, the margins on both sides of the recording paper can be removed. This margin erasing shutter section is driven to 5 so that it is always open (light transmission). In addition, in FIG. 1, St%S is a test segment sleep pole formed outside the auxiliary segment electrodes SO, SO, and the test segment electrodes st, s
t also faces the common electrodes CI and C2 of the common board 22 to form a test shutter section. 23c123c
is a spacer which is provided with pressure on both sides of the test segment electrodes st and st and maintains the distance between the side substrates 21 and 22.

In addition, in order to make the poles So, So and the test segments 'hidden poles st and st face the common electrodes C1 and C2 of the common board 22, the buttons and the common board 22
The metal film 28.2 deposited on the common electrodes C1 and C2 of
8 is an auxiliary segment electrode So of the common electrodes C1 and C2.
, So and test segment electrodes st and portions 28b, 28b and 28c, 28c facing st are exposed (see FIG. 5).

Further, in FIG. 7, 35 is a polarizing plate.

This liquid crystal element 20 is a liquid crystal element 20 as shown in FIG.
From the drive circuit 40 connected to each segment electrode S1, S
l,..., S2, S2,... and common electrodes CI, C
A driving signal is applied between the two and the two frequencies, and the pivoting is performed at two frequencies in a time r division.

This two-frequency drive method utilizes the dielectric dispersion phenomenon of liquid crystal,
A high frequency electric field is applied to the liquid crystal to align the liquid crystal molecules perpendicular to the electric field, and a low frequency electric field is applied to align the liquid crystal molecules between the electric fields C1 and C2 (Fig. 9).
When a driving voltage having a waveform as shown at is applied to close (non-transparent) the shutter parts a, a, . . . , each segment electrode S1, Sl, . . . , S2, S2, . A drive voltage having a waveform as shown in FIG. 9 0))K is applied between the common electrodes C1 and C2. Note that FIG. 9 shows a waveform of one cycle T1 for controlling the shutter sections a, a, . . . , and this drive waveform is set to the following conditions.

Drive voltage Vop = 25V (constant) Tl = 2ms T2 = T3: 1ms low frequency drive frequency = 5KHz High frequency drive frequency = 320I (Hz) Therefore, each shutter section a of the liquid crystal element 20 shown in FIG.
, a... are low frequency or high frequency starting voltages (T
The open or closed state is maintained by a continuous voltage (signal in the Ta time period) with a waveform in which the voltage at the high frequency and the voltage at the high frequency are superimposed. The arranged shutter parts a, a,...
Each shutter section a is driven in a time-division manner with T1 as one cycle for each column.

A, . . . are independently controlled to open and close.

By the way, during the manufacturing process, this liquid crystal element 20 has an absolute amount of transmitted light when the shutter parts a, a, . . . Electro-optical characteristics such as light intensity ratio (contrast) and response speed are inspected.

The electro-optical characteristics are measured using test segment electrodes formed in the liquid crystal reservoirs F and F of the liquid crystal element 20.
, st is used.

That is, the test shutter section K and the photodetector section of the measuring device are made to correspond to each other, and the test segment electrodes St, St.
The above-mentioned I
By applying a 'lJ voltage to control the opening and closing of the test shutter section and detecting the transmitted light at that time,
It is possible to measure various electro-optical properties of.

In this case, the test shutter section can be provided at any location on the liquid crystal element in relation to the measuring device.

In addition, this test shutter section includes shutter sections a, a,...
-・Can be formed into a larger area. Therefore, the ratio of the light controlled by the liquid crystal element 20 to other leakage light (
The S/N ratio) becomes large, and high accuracy in alignment between the detection area of the liquid crystal element and the light detection area of the measuring device is not required, making measurement easy and accurate.

In addition, since the test shutter section can be set at any position, even when manufacturing liquid crystal elements with different shapes, etc., the test shutter section can be set at a position that corresponds to the measuring device. , it is possible to accurately and easily measure various characteristics of different liquid crystal elements.

In the above-described embodiment, the test shutter sections are arranged in rows formed in both liquid crystal reservoir sections F, F, which are provided at both ends of the narrow gap E in which the shutter sections a, a, . . . are arranged. However, the present invention is not limited to this, and the liquid crystal reservoir portions may be formed only in one of the liquid crystal reservoir portions F, F. Furthermore, the test shutter section of the present invention may be formed at any position between opposing substrates in which liquid crystal is sealed.

〔Effect of the invention〕

In addition to a large number of minute shutter sections, the present invention forms a test shutter section for measuring the electro-optic characteristics of a liquid crystal element, and this test shutter section can be any suitable for the measurement. Since the electro-optical characteristics of each liquid crystal element can be easily and accurately measured, there is an advantage that the electro-optic characteristics of each liquid crystal element can be easily and accurately measured.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show one embodiment of the present invention, in which FIG. 1 is a cross-sectional view of a liquid crystal element showing the sealing material cut along a plane parallel to the segment substrates, FIG. Figure 3 is a schematic diagram of an optical writing printer that performs optical writing using a liquid crystal element, and a configuration diagram of its optical recording section. Figure 4 is a plan view of the liquid crystal element. Figure 5 is a common view of the liquid crystal element. A plan view of the substrate, FIG. 6 is an enlarged plan view of the segment electrode forming portion of the segment substrate, FIG. 7 is a cross-sectional view of the liquid crystal element along line A-A in FIG. 6, and FIG. 8 is a cross-sectional view of the liquid crystal element in FIG. FIG. 9, which is an enlarged view of the shutter portion, is a drive waveform diagram of the liquid crystal element. 21.22... Substrate, Sl, S2... Segment electrode, CI, C2... Common electrode, a... Shutter section, St... Test electrode, E... Narrow gap, F・・・
・Liquid crystal reservoir.

Claims (1)

[Claims] In a liquid crystal element, a plurality of micro shutters are formed by a plurality of shutter electrodes arranged to face each other on the inner surfaces of a pair of substrates arranged opposite to each other, and a liquid crystal interposed between the pair of substrates. 1. A liquid crystal device comprising: a test electrode formed on the inner surface of at least one of the substrates, the test electrode facing an electrode formed on the inner surface of the other substrate.