JPH0245846Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Technical Field of the Invention] This invention relates to a liquid crystal device including a liquid crystal shutter that controls transmission of light from a light source. [Prior Art] In recent years, liquid crystal devices have been known in which a liquid crystal shutter is driven at high speed using a dual frequency drive method. In other words, a liquid crystal shutter using a dual-frequency driving method uses a dual-frequency driving liquid crystal whose dielectric anisotropy is reversed depending on the driving frequency. The dielectric anisotropy is positive at low frequencies below the crossover frequency, and negative at high frequencies. In a dual-frequency drive liquid crystal having such characteristics, the opening and closing of the liquid crystal shutter is controlled by applying a low frequency signal and a high frequency signal. This type of liquid crystal device is used, for example, in an exposure section of an electrophotographic printing device. That is, a strip-shaped liquid crystal shutter section including a plurality of minute shutters arranged along the axial direction of the photosensitive drum is provided near the photosensitive drum, and this liquid crystal shutter section is used to control the transmission of light from the light source. It is used in electrophotographic printers that form an image on the surface of a photosensitive drum and transfer this image to paper. [Problems with the Prior Art] In general, liquid crystal devices are affected by changes in external temperature, and when the temperature is high, the internal pressure of the liquid crystal cell increases, causing the cell container to swell outward. Sometimes, as the internal pressure of the liquid crystal cell decreases, the shape of the cell container changes so that the cell container dents inward, so changes in external temperature
It can be absorbed by changing the cell container.
However, in the device using the elongated strip-shaped liquid crystal shutter section described above, the width of the liquid crystal layer is narrow, so the cell container cannot be sufficiently deformed in response to changes in external temperature, and as a result, the inside of the cell container cannot be deformed sufficiently. However, there was a problem in that there was a risk of air bubbles being generated or liquid leakage, which significantly reduced reliability. [Purpose of the invention] This invention was made against the background of the above-mentioned circumstances, and its purpose is to ensure that changes in external temperature can be reliably absorbed even if the liquid crystal shutter section is formed into a long and narrow strip. An object of the present invention is to provide a liquid crystal device that can improve reliability against changes in external temperature. [Main points of the invention] In order to achieve the above-mentioned purpose, this invention
The main point is that a liquid crystal reservoir section is provided which communicates with the liquid crystal shutter section. [Configuration of Embodiment] This embodiment is applied to a guest-host effect type liquid crystal device, and this liquid crystal device is configured as shown in FIGS. 1 and 2. In the figure, 1 is a liquid crystal shutter section in which a plurality of minute shutters Sn (for example, 1≦n≦1500) are formed. The minute shutter Sn is
It has a square dot shape arranged in a zigzag pattern, and in this example, dichroic dye (guest)
By using a liquid crystal composition in which is added to the liquid crystal material (host), it is constructed as a guest-host effect type liquid crystal element that utilizes the light absorption anisotropy of the dye. That is, in FIG. 2, among a pair of glass substrates 3 and 4 that face each other vertically with a liquid crystal layer 2 formed by adding dichroic dye added to a liquid crystal for dual-frequency driving, the inner surface of the lower glass substrate 3 is A plurality of scanning electrodes 5, 5 (two in this embodiment) extending in the horizontal direction are formed, and a plurality of scanning electrodes (650 in this embodiment) extending in the vertical direction are formed on the inner surface of the upper glass substrate 4. Signal electrodes 6, 6, . . . are formed, and each liquid crystal shutter Sn is formed of a part of a portion where a plurality of scanning electrodes 5, 5 and signal electrodes 6, 6, . . Moreover, on the inner surfaces of the upper and lower glass substrates 3 and 4,
On the transparent conductive films 7 and 8 constituting the scanning electrode 5 and the signal electrode 6, a metal conductive layer (chromium thin film) is formed on the other parts except for the part constituting the minute shutter Sn.
9 and 10 are formed, and on these metal conductive layers 9 and 10, insulating layers (polyimide resin) 11 and 12 are formed so as to cover the transparent conductive films 7 and 8. Here, the metal conductive layers 9 and 10 are for optically masking parts other than the minute shutter Sn, and the insulating layers 11 and 12 are for controlling liquid crystal molecules by horizontal alignment treatment applied to their surfaces. This is for homogeneous arrangement. Note that the other parts of the transparent conductive film 8 constituting the signal electrode 6 are the lead wire part 13 and the connection terminal part 1.
4. Furthermore, inner seal members 15 are provided on both sides of the liquid crystal shutter section 1 between the upper and lower glass substrates 3 and 4 and on the scanning electrodes 5 and 5. Furthermore, an outer seal member 16 disposed outside the inner seal member 5 is provided on the scanning electrodes 5, 5 near the peripheral edge between the upper and lower glass substrates 3, 4. That is, the liquid crystal device of this embodiment has a double seal structure, and air spaces 17 and 18 are provided on both sides of the liquid crystal shutter section 1 in the width direction, respectively. Note that the air layers 17 and 18 are
The space between the upper and lower glass substrates 3 and 4 is sealed by inner and outer seal members 15 and 16. In addition, liquid crystal reservoir portions 19 communicating with the liquid crystal shutter portion 1 are provided at both ends in the length direction of the liquid crystal shutter portion 1.
20 are provided. This liquid crystal reservoir 19, 20
is surrounded by inner and outer seal members 15 and 16 between the upper and lower glass substrates 3 and 4, and has a wide rectangular box shape as a whole. Also, one of the liquid crystal reservoirs 19 and 20, in this embodiment, the liquid crystal reservoir 19 on the right side in FIG.
A liquid crystal injection port 21 is formed in the. In this case, the liquid crystal injection port 21 is provided in the outer seal member 16 on the center line in the width direction of the liquid crystal shutter section 1, and is sealed after the liquid crystal is injected. It should be noted that the liquid crystal reservoirs 19 and 20 are not directly involved in driving the liquid crystal shutter section 1, but merely serve to store liquid crystal. Further, the liquid crystal reservoir 19 is provided with test electrodes T for testing the transmittance, operability, etc. of the liquid crystal material. This test electrode T is formed on the inner surface of the upper glass substrate 4 and faces the scanning electrodes 5, 5, respectively. Note that seal members 22, 22 are provided near both sides of the test electrode T. The seal members 22, 22 are provided on an extension line of the inner seal members 15, 15 forming both side walls of the liquid crystal shutter section 1, and the distance between the inner walls matches the width of the liquid crystal shutter section 1. [Operation of the Embodiment] According to the liquid crystal device configured as described above, liquid crystal reservoirs 1 are provided at both longitudinal ends of the liquid crystal shutter section 1, respectively, and the liquid crystal reservoirs 1 communicate with the liquid crystal shutter section 1.
9 and 20 are provided, a change in the volume of the liquid crystal caused by a change in external temperature can be absorbed by the liquid crystal reservoir 19. That is, at high temperatures, the liquid crystal reservoir 1
As the internal pressure of the liquid crystal reservoirs 9 and 20 increases, the upper and lower glass substrates 3 and 4 of the liquid crystal reservoir 19 swell outward, and at low temperatures, as the internal pressure of the liquid crystal reservoirs 19 and 20 decreases, the liquid crystal reservoir 19 expands outward. The upper and lower glass substrates 3 and 4 of the portion 19 are recessed inward. Therefore,
Even in the case where the elongated strip-shaped liquid crystal shutter section 1 is used, by providing the liquid crystal reservoir sections 19 and 20 that communicate with the liquid crystal shutter section 1, the influence of external temperature changes can be reduced to the area where the liquid crystal reservoir section 19 is formed. This can be absorbed by deformation of the upper and lower glass substrates 3 and 4. As a result, there is no risk of bubbles occurring in the cell container or liquid leakage, and reliability against changes in external temperature is improved. Here, a test was conducted to confirm the effectiveness of the liquid crystal device.
This effect confirmation test was conducted by selecting various sizes of the liquid crystal reservoirs 19 and 20 for the liquid crystal shutter part 1 of a certain size, and conducting each of them under the following conditions.
That is, first, the following five types of liquid crystal reservoirs 19 and 20 for the liquid crystal shutter section 1 were used.

[Effect of idea]

As explained in detail above, this invention has a liquid crystal reservoir that communicates with the liquid crystal shutter, so even if the liquid crystal shutter is formed into a long and narrow strip, the liquid crystal reservoir will not be affected by fluctuations in external temperature. Changes in the volume of the liquid crystal can be absorbed, and as a result, there is no risk of bubbles being generated in the cell container or liquid leakage, and reliability against temperature changes can be significantly improved.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention, and FIG.
is a sectional view taken along the line A-A in Figure 2, and Figure 1B is a cross-sectional view taken along the line A-A in Figure 2.
An enlarged view of the X part shown in Figure 2 is B-B in Figure 1A.
FIG. 1...Liquid crystal shutter section, 19, 20...Liquid crystal reservoir section.

Claims (1)

[Scope of utility model registration request] a liquid crystal shutter portion having a predetermined width for controlling transmission of light from a light source between a pair of opposing substrates;
A liquid crystal device comprising: a liquid crystal reservoir portion having a width wider than the width of the liquid crystal shutter portion, communicating with the liquid crystal shutter portion, and being filled with liquid crystal.