JPS60203916A - Curved liquid crystal cell and antidazzle type reflection mirror using said cell - Google Patents

Abstract

PURPOSE:To prevent the fluctuation of the shadow pattern in the stage of preventing and not preventing dazzle by holding a pair of glass substrates having electrode layers on the inside end face and different thicknesses at a specified space by means of a spacer, interposing a liquid crystal between the substrates and impressing a voltage thereto to change the transmittance of light. CONSTITUTION:A curved liquid crystal cell provided to a frame body 2 of an antidazzle type reflection mirror has a glass substrate 4 having the curved surface shape deformed to 1.1mm. thickness and 1,800mm. radius of curvature. A transparent electrode layer 6 and an oriented film 8 are formed to the end face in the recess of the substrate 4. On the other hand, a glass substrate 16 deformed to 0.55mm. thickness and 1,900mm. radius of curvature is provided to face the substrate 4 and a transparent electrode layer 14 and an oriented film 12 are formed to the end face in the projecting part. A metallic reflecting layer 20 is formed on the other end face of the substrate 16. A spacer 30 formed by dispersing spherical glass beads in ethanol and coating the same by a spinner is provided in the cell. A liquid crystal is injected into the cell and the peripheral part of the substrates 4, 16 is adhered by an adhesive agent 24. An electric field is applied to the electrode layers 6, 14 in the stage of preventing dazzle. The fluctuation in the shade pattern in the stage of preventing and not preventing the dazzle is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a curved liquid crystal cell and an anti-glare reflector using the curved liquid crystal cell. The present invention can be used for curved liquid crystal display panels and automobile rearview mirrors such as door mirrors and fender mirrors.

[Prior Art] Liquid crystal cells conventionally used in liquid crystal displays have generally been parallel plate-shaped using glass substrates, and liquid crystal cells with a certain curvature have not been manufactured very often. . This is due to the following reason. That is, when creating a curved liquid crystal cell, a glass substrate is polished or thermally deformed to create a curved surface with a certain curvature, and a pair of curved glass plates created in this way are They are arranged parallel to each other to form a curved liquid crystal cell. However, the interval between injections of liquid crystal in a liquid crystal cell is extremely narrow, approximately 10 μm, and it is necessary to form a uniform curved surface. However, with the above method, even if a pair of glass substrates are deformed to the same curvature, when they are joined into a cell shape, distortion occurs due to the rigidity of the glass, making it difficult to form a uniform width across all gaps. was difficult. This uneven spacing is particularly important for TN
This has been a major drawback in terms of display quality when using liquid crystals such as liquid crystals and field-controlled birefringence effect liquid crystals whose characteristics are affected by the distance between electrodes.

In order to improve these drawbacks, a device was invented in which one substrate was made of glass and the other was made of a flexible thin plastic film (Japanese Patent Publication No. 58-58).
5487). Point 5: If the other substrate is made of plastic, there will be a problem with the sealing properties of the liquid crystal layer, and moisture will penetrate into the liquid crystal from the outside, causing rust and deteriorating the performance and life of the liquid crystal element. There is.

On the other hand, a liquid crystal element is used in the rearview mirror of a car to electrically control the light transmittance, and when the headlight beam from the following car enters the rearview mirror directly, the liquid crystal element A liquid crystal anti-glare type reflector has been devised which has an anti-glare function by reducing the transmittance of the reflector. However, in such a liquid crystal anti-glare reflector, a liquid crystal cell using parallel flat glass substrates is used as a liquid crystal element.

When forming a door mirror or fender mirror as a liquid crystal anti-glare reflector, it was devised to form it as shown in Figure 1 using a liquid crystal hill with a pair of parallel glass substrates. There is. That is, the fender mirror has a frame 2, and the frame 2 has a liquid crystal cell. The liquid crystal cell includes a transparent glass substrate 4 formed on the light incident side, a transparent electrode layer 6 made of ITO formed on the end surface of the glass substrate 4, an alignment treatment film 8 formed on the end surface, and a glass substrate 4. It has a glass substrate 16 provided on the side opposite to the substrate 4, a transparent electrode layer 14 formed on the end surface thereof, and an alignment treatment film 12 formed on the end surface. The glass substrates 4 and 16 are held parallel to each other with a constant width of 10 μm by a spacer 24 made of epoxy resin, and the liquid crystal 10 is mixed into the formed gap. Further, the other end surface of the glass substrate 16 is curved in a convex shape when viewed from the light incident direction, and a metal reflective layer 20 is formed on the surface thereof.

Also, an optical sensor 22 is installed on the outer periphery of the frame 2 to detect the intensity of incident light, and in response to the signal detected by the optical sensor 22, the transparent electrode layers 6 and 14 of the liquid crystal cell are driven. By applying a voltage, the transmittance of light passing through the liquid crystal layer 10 can be reduced to provide an anti-glare effect. Here, when the glare is not on, the light passes through the liquid crystal layer 10 and the metal reflective layer 2.
0 and thus an image reflected by a convex mirror is obtained. However, since the light is blocked by the liquid crystal layer 10 and does not reach the metal reflective layer 20, the image obtained during anti-glare is reflected by the light incident end surface 4a of the glass substrate 4. Therefore, during -C anti-glare, the image becomes a reflected image by a plane mirror. Therefore, if such parallel liquid crystal cells are used in the fender mirror to form an anti-glare reflector, the light reflecting surface will switch between a flat surface and a curved surface when anti-glare and non-anti-glare, resulting in an image The disadvantage is that it fluctuates.

In addition, when the glare is not on, the convex surface effect allows a wide rear field of view, but when the glare is off, there is a drawback that the rear field of view is narrowed due to reflection from the plane mirror. Furthermore, some of the light that has passed through the liquid crystal layer is reflected by the convex metal reflective layer, and the combined image is created by these layers, resulting in a ghost image, making it impossible to obtain a clear image. There are drawbacks.

[Object of the Invention] That is, the present invention has been made to improve the above-mentioned drawbacks, and the first invention is directed to a general liquid crystal display which has excellent moisture resistance and is capable of displaying three-dimensional images. The second invention aims to provide a curved liquid crystal cell used in a display device, and the second invention
An object of the present invention is to provide an anti-glare reflector for convex or concave mirrors such as fender mirrors of automobiles.

[Structure of the Invention] That is, the first invention provides a pair of curved glass substrates having an electrode layer on their inner end surfaces, a spacer that holds the pair of curved glass substrates at a constant interval, and a spacer that holds the pair of curved glass substrates at a constant interval. and a liquid crystal interposed therebetween, wherein one of the glass substrates is thinner than the other glass substrate.

The pair of glass substrates used in this liquid crystal cell can be made of borosilicate glass, soda glass, or the like.

Furthermore, a hot press method can be used to deform the pair of glass substrates to a constant curvature. A spacer is provided to hold the pair of curved glass substrates at a constant distance. This spacer can be made of spherical or columnar glass fiber, glass beads, alumina powder, or the like. Further, the particle size used is determined according to the gap between the liquid crystal cells. This spacer can be formed by blowing the above-mentioned spherical or columnar glass fiber onto the glass substrate with compressed air, or by dispersing it in ethanol and applying it with a spinner. One of the pair of glass substrates is thinner than the other glass substrate. The thickness of the thinner glass substrate is 0.
It is desirable to exist in the range of 4 to 0.6. In this way, the present invention allows the thicker glass substrate to have a defined curvature of the liquid crystal cell, and the other glass substrate to be thinner than it, i.e., the thickness (relative to one glass substrate) By reducing the rigidity of the glass substrate and making the curvature of the thinner glass substrate follow the curvature of the thicker glass substrate, a curved liquid crystal cell with a uniform width throughout can be obtained. The radius of curvature of the thicker glass substrate is desirably larger than the radius of curvature of the thicker glass substrate.

The second invention is an anti-glare reflecting mirror using the curved liquid crystal cell according to the first invention as an element for electrically changing light transmittance. Generally, such anti-glare reflectors are
The curved liquid crystal cell has a frame, and a metal reflective layer is formed on one end surface of the glass substrate by vapor deposition. Further, this metal reflective layer can also be formed on the side where the liquid crystal is present and can also be used as an electrode layer. The liquid crystal used in this curved liquid crystal cell can be any one such as DSM liquid crystal or TN type liquid crystal. Furthermore, a half mirror may be used instead of the metal reflective layer, and an optical sensor may be provided inside the frame of the anti-glare reflecting mirror to detect the light transmitted through the half mirror. Furthermore, an electronic circuit for driving the curved liquid crystal cell may be provided within the frame. The present invention will be explained in detail below based on specific examples.

[Example] FIG. 2 is a cross-sectional view showing the configuration of a curved liquid crystal cell according to a specific example of the first invention. Thickness 1.1
A glass substrate 16 made of borosilicate glass with a diameter of 1.0 mm is deformed by heat pressing to have a radius of curvature of 1500 mm, a transparent electrode 14 made of ITO is deposited on it by sputtering, and then a photoresist is applied and a portion of the light is shielded with a photomask. After exposure to ultraviolet rays, etching was performed to form the transparent electrode ff114 into a predetermined segment shape. Next, a glass substrate 4 made of borosilicate glass with a thickness of 0.55 mm was deformed by hot pressing to a radius of curvature of 1800 mm, and then ITO was similarly sputtered to form a transparent electrode layer 4.
was formed, and then etched by a predetermined process to form a segment-shaped transparent electrode layer 6. After that, polyimide was applied so that the nematic liquid crystals formed a twisted alignment, and then the alignment treatment was performed by rubbing.Alignment treatment II!
8 and 12 were formed. After that, diameter 12μ, length 30~
A columnar glass fiber of 40 μm is blown onto the glass substrate 16 using compressed air, the opposing glass substrates 4 are aligned in a predetermined position, and the periphery is coated with an epoxy adhesive 24.
It was sealed with. A nematic liquid crystal was mixed into the gap between the substrates, and a polarizer 35 and an analyzer 36 were arranged on the outer end surface of the glass substrate 14.4 to form a TN type liquid crystal cell. Then, light was irradiated from a light source 40 placed on the back side of the glass substrate 16 to form a transmissive liquid crystal display. By forming the display in this way, the distance between the liquid crystal cells became constant and uniform at 12 μm, preventing uneven display brightness and providing a three-dimensional display.

FIG. 3 is a cross-sectional view showing the structure of an anti-glare reflecting mirror according to a specific embodiment of the second invention.

This anti-glare reflecting mirror has a frame 2, inside which a curved liquid crystal cell is arranged. The curved liquid crystal cell has a thickness of i, In+
The glass substrate 4 has a convex curved surface deformed by heat pressing to have a radius of curvature of 1800 mm. A transparent electrode layer 6 made of ITO is formed on the end face of the concave portion of the glass substrate 4 to a thickness of 1000 nm by sputtering. On top of that, an alignment treatment film 8 is formed to a thickness of 1200 mm, which is formed by applying polyimide and then rubbing it. On the other hand, thickness 0.551111111 radius of curvature 1900+n
A glass substrate 16 made of soda glass, which is formed by deforming with a press 1 through a press, is placed opposite the glass substrate 4, and a transparent electrode layer 14 made of ITO is formed on the end surface of the convex portion to a thickness of Furthermore, an alignment film 12 made of polyimide is formed on the end face to a thickness of 1,200 mm. Further, on the other end surface of the glass substrate 16, a metal reflective layer 20 is formed by vapor depositing chromium. A curved liquid crystal cell is formed by holding the pair of glass substrates 4 and 16 formed in this manner in parallel. In addition, spacers 3 were formed by dispersing spherical glass beads with a diameter of 10 μm in ethanol and applying them using a spinner.
0 is set. This spacer 30 is used to maintain a gap for injecting liquid crystal at a constant interval. The peripheral portions of the pair of glass substrates were bonded together with an epoxy adhesive 24, and the glass substrate 4 was matched to the curvature of the glass substrate 16 to form a curved liquid crystal cell.

On the other hand, a lead wire 26 for supplying power from outside the frame 3 is connected to the transparent electrode layers 6 and 14. Furthermore, a photodiode 22 for detecting the intensity of light incident from the front of the frame body 2 is installed (KJI), and the signal detected by the photodiode is provided on the vehicle body side via a signal line (not shown). The electronic circuit processes the signal from the photodiode 22, and when the signal reaches a certain level or higher, applies an AC voltage to the transparent electrode layers 6 and 14, and controls the light in the liquid crystal layer. By reducing the transmittance, the reflectance of light can be reduced.In this way, in this embodiment, when non-glare is
An image reflected by a metal reflective layer 20 made of chromium formed on the end face of the glass substrate 16 is obtained. Further, during anti-glare, an image is obtained by the light reflected from the end surface 4a of the glass substrate 4 on the light incident side. Therefore, since the curvature of the end face 4a and the metal reflective layer 20 are made equal, there is no problem that the pattern of the statue changes between the anti-glare and non-anti-glare states. Further, during anti-glare operation, a part of the incident light 11 is reflected by the metal reflective layer 20, but since the curvature of the plane of incidence of both layers is equal, the ghost of the image can be suppressed to a small level.

[Effects of the Invention] In summary, the first invention is a curved liquid crystal cell in which one glass substrate is formed thinner than the other glass substrate. Therefore, since the thinner glass substrate with lower rigidity can be easily deformed along the curved surface of the thicker glass substrate, a gap of uniform width can be formed over the entire curved surface. Therefore, display unevenness can be prevented. Also, since both substrates are made of glass, they have excellent moisture resistance.

Therefore, deterioration of the display of the liquid crystal cell can be prevented and the field can be lengthened. Moreover, the second invention is an anti-glare reflecting mirror using the above curved liquid crystal cell. Therefore, even in the anti-glare mode and in the non-glare mode, the light is reflected by the reflecting surface having the same radius of curvature, so that no image fluctuation occurs when the anti-glare switch is made. Furthermore, since both substrates of the curved liquid crystal cell are made of glass, it has excellent moisture resistance and can be used as a fender mirror for automobiles, etc.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of an anti-glare fender mirror using a conventional liquid crystal cell. FIG. 2 is a cross-sectional view showing the structure of a curved liquid crystal cell according to a specific embodiment of the first invention. FIG. 3 is a cross-sectional view showing the structure of an anti-glare reflector using a curved liquid crystal cell according to a specific embodiment of the second invention. 4.16...Glass substrate 6.14...Transparent electrode layer 8.12...Alignment treatment film 10...Liquid crystal 30...Spacer 40...Light source Fig. 1

Claims (1)

[Scope of Claims] (1) A pair of curved glass substrates having electrode layers on their inner end surfaces, a spacer that holds the pair of curved glass substrates at a constant distance, and a spacer interposed between the pair of glass substrates. Consisting of a liquid crystal and
A curved liquid crystal cell in which one of the glass substrates is thinner than the other glass substrate. (2) The thickness of the thinner glass substrate is within a range of 0.4 to 0.6 with respect to the thickness of the thicker glass substrate. curved liquid crystal cell. (3) The curved liquid crystal cell according to claim 1, wherein the radius of curvature of the thinner glass substrate is larger than the radius of curvature of the thicker glass substrate. (4) Application of electric field In a liquid crystal anti-glare reflector having a liquid crystal cell that changes light transmittance according to Consisting of a spacer that holds the substrates at a constant interval, and a liquid crystal interposed between the pair of glass substrates,
An anti-glare reflecting mirror characterized in that one of the glass substrates is composed of a curved liquid crystal cell that is thinner than the other glass substrate. (5) The thickness of the thinner glass substrate is within a range of 0.4 to 0.6 with respect to the thickness of the thicker glass substrate. anti-glare reflector. (6) The anti-glare reflector according to claim 4, wherein the radius of curvature of the thinner glass substrate is larger than the radius of curvature of the thicker glass substrate.