JP3225094U - Reflective liquid crystal cell - Google Patents

Abstract

An object of the present invention is to provide a reflection type liquid crystal cell which can reduce distortion of a reflection image when used as a mirror. The reflective liquid crystal cell includes a first polarizing plate 2 that transmits one of orthogonal polarization components and reflects the other, and a liquid crystal unit 3 disposed on the front surface 2a side of the first polarizing plate. A second polarizing plate 4 disposed on the front surface 3a side of the liquid crystal unit and transmitting a predetermined polarization component of incident light to the liquid crystal unit and transmitting incident light from the liquid crystal unit; and a front surface 4a of the second polarizing plate And a transparent undulation layer 5 made of resin and a cover glass 6 arranged on the front surface 5a of the undulation layer, and the undulation layer bonds the second polarizing plate and the cover glass. At the same time, it absorbs the undulation on the front surface of the second polarizing plate. [Selection] Figure 2

Description

  The present invention relates to a reflection type liquid crystal cell.

  Patent Literature 1 discloses a liquid crystal anti-glare mirror that can be used as a monitor when the power is on and can be used as a mirror when the power is off. The liquid crystal anti-glare mirror includes a first polarizing plate (reflection type polarizing plate) for reflecting incident light, a liquid crystal unit disposed on the front side of the first polarizing plate, and a second polarizing plate formed on the front side of the liquid crystal unit. And a polarizing plate (absorption-type polarizing plate).

JP 2009-8881 A

  In the invention described in Patent Literature 1, since the front surface of the second polarizing plate has large undulation, there is a problem that, when the power is turned off and used as a mirror, the distortion of the reflected image is larger than that of a normal mirror. .

  The present invention has been made in view of such a point, and an object of the present invention is to provide a reflection type liquid crystal cell which can reduce distortion of a reflection image when used as a mirror.

  In order to solve the problem of the distortion described above, the present invention provides a first polarizing plate that reflects incident light, a liquid crystal unit disposed on the front side of the first polarizing plate, and a liquid crystal unit disposed on the front side of the liquid crystal unit. A second polarizing plate that transmits a predetermined polarization component to the liquid crystal unit and transmits incident light from the liquid crystal unit, and a transparent undulation layer made of resin, which is disposed on a front surface of the second polarizing plate. And a cover glass disposed on the front surface of the undulation layer, wherein the undulation layer adheres the second polarizing plate and the cover glass and undulates the front surface of the second polarizing plate. Is absorbed.

  According to this configuration, the undulation on the front surface of the second polarizing plate is absorbed by the undulation layer, and the front surface of the undulation layer is flattened by the cover glass. Thereby, the distortion of the reflected image when used as a mirror can be reduced.

  The present invention also provides a first polarizing plate that reflects incident light, a liquid crystal unit disposed on the front side of the first polarizing plate, and a liquid crystal unit disposed on the front side of the liquid crystal unit, and converts a predetermined polarization component into the liquid crystal. A second polarizer that transmits incident light from the liquid crystal unit, and a transparent undulation layer made of a resin, which is disposed on the front surface of the second polarizer. The layer has a flat front surface and absorbs undulations of the front surface of the second polarizing plate.

  According to such a configuration, the undulation on the front surface of the second polarizing plate is absorbed by the undulation absorption layer, and the front surface of the undulation absorption layer is flat. Thereby, the distortion of the reflected image when used as a mirror can be reduced.

  According to the reflective liquid crystal cell of the present invention, the distortion of the reflected image when used as a mirror can be reduced.

FIG. 1 is a perspective view showing a reflective liquid crystal cell and a liquid crystal monitor according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a reflective liquid crystal cell and a liquid crystal monitor according to the first embodiment. It is an expanded sectional view showing the 2nd polarizing plate concerning a first embodiment. It is a figure which shows the comparative example of contrast observation, (a) is a top view and (b) is sectional drawing. It is a figure which shows the model example of contrast observation, (a) is a top view and sectional drawing. It is sectional drawing which shows the reflective liquid crystal cell which concerns on 2nd embodiment.

[First embodiment]
A reflective liquid crystal cell according to a first embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the reflective liquid crystal cell 1 according to the present embodiment includes a first polarizer 2, a liquid crystal unit 3, a second polarizer 4, a swell absorbing layer 5, a cover glass 6. It is mainly composed of

  The reflection type liquid crystal cell 1 is a plate-like member having a rectangular shape in a plan view. The reflection type liquid crystal cell 1 becomes substantially transparent when the liquid crystal unit 3 is energized, and functions as a mirror when the energization to the liquid crystal unit 3 is cut off. On the back surface of the reflection type liquid crystal cell 1, for example, a liquid crystal monitor M is arranged. A monitor image of a camera or the like can be displayed via the reflective liquid crystal cell 1 while the power of the reflective liquid crystal cell 1 and the liquid crystal monitor M is turned on. By arranging the liquid crystal monitor M on the back surface, the reflective liquid crystal cell 1 can be used for, for example, a smartphone, a vehicle electronic mirror, a game machine, and the like. Further, the reflection type liquid crystal cell 1 can be used as an anti-glare mirror for a vehicle whose reflectance can be adjusted. Note that another display device may be provided instead of the liquid crystal monitor M. The surface of the reflective liquid crystal cell 1 that is visible to the user is referred to as “front”, and the surface opposite to “front” is referred to as “back”.

  The first polarizing plate (reflection-type polarizing plate) 2 is a thin film in a rectangular shape in a plan view that transmits one of orthogonal polarization components and reflects the other. The first polarizing plate 2 is arranged at the rearmost side in the reflective liquid crystal cell 1. As the first polarizing plate 2, for example, a DBEF series reflective polarizing film manufactured by 3M can be used. The plate thickness of the first polarizing plate 2 can be appropriately set, for example, between about 50 to 300 μm. In the present embodiment, the thickness of the first polarizing plate 2 is set to 100 μm.

  The size of the waviness (unevenness) of the front surface 2a of the first polarizing plate 2 (difference between the most protruded portion and the most recessed portion in a predetermined length in the plane direction of the polarizing plate) is, for example, less than 1.0 μm. . Since the first polarizing plate 2 has a function of reflecting incident light, the magnitude of the undulation on the front surface 2a affects the reflected image. That is, if the front surface 2a of the first polarizing plate 2 has a large undulation, a problem that the contour of the reflected image is blurred occurs. However, since the first polarizing plate 2 is a softer material than the second polarizing plate 4, the first polarizing plate 2 has a property that the undulation is easily reduced.

  The liquid crystal unit 3 is a plate-shaped member arranged on the front surface 2a of the first polarizing plate 2. The liquid crystal unit 3 has a substantially same planar shape as the first polarizing plate 2. The liquid crystal unit 3 functions as a shutter for transmitting light. The liquid crystal unit 3 is configured by sealing liquid crystal between a pair of glass substrates (not shown). The type of the liquid crystal unit 3 is not particularly limited. For example, a TN (Twisted nematic) liquid crystal can be used. When no voltage is applied between the transparent electrodes of the glass substrate (no voltage is applied), the liquid crystal unit 3 exhibits optical rotation with respect to incident light. On the other hand, the liquid crystal alignment is such that the optical rotatory power that is exhibited when a voltage is applied (applied) between the transparent electrodes is eliminated.

  The second polarizing plate (absorption type polarizing plate) 4 is a thin film member disposed on the front surface 3 a of the liquid crystal unit 3. The second polarizing plate 4 emits a specific polarization component of the incident light incident from the front side to the liquid crystal unit 3 as transmitted light, and transmits a specific polarization component of the incident light incident from the liquid crystal unit 3 to the front side. Let it. The second polarizing plate 4 has substantially the same planar shape as the first polarizing plate 2. As the second polarizing plate 4, for example, a polarizing plate manufactured by PORA TECHNO can be used. An undulation (unevenness) is formed on the front surface 4a of the second polarizing plate 4.

  As shown in FIG. 3, the front surface 4a of the second polarizing plate 4 is formed with a relatively large undulation. Further, the front surface 4a is formed with "roughness" which becomes minute unevenness. In addition, for convenience of explanation, the undulation in each drawing is drawn larger than the actual size. The magnitude h of the undulation of the front surface 4a of the second polarizing plate 4 (the difference between the most protruding portion and the most recessed portion in a predetermined length in the plane direction of the polarizing plate) is about 1.0 to 2.5 μm. The back surface 4b of the second polarizing plate 4 is flattened by being bonded to the glass substrate of the liquid crystal unit 3 via an adhesive layer (PSA: Pressure Sensitive Adhesive not shown) and pressed.

  As shown in FIG. 2, the undulation layer 5 absorbs undulation and “roughness” of the front surface 4 a of the second polarizing plate 4, and is a transparent curable resin that adheres the second polarizing plate 4 to the cover glass 6. Layer. In other words, the swell absorbing layer 5 can improve the flatness by filling the undulations of the front surface 4a and the unevenness of “roughness”. As the swell absorption layer 5, for example, OCA (Optical Clear Adhesive): product number MHM = FWD100 manufactured by Niei Chemical Co., Ltd. can be used. As the OCA, any of a urethane-based material, an acrylic-based material, and an epoxy-based material can be used.

  The thickness of the undulation layer 5 can be appropriately set between 1 and 100 μm. If the thickness of the swell absorbing layer 5 is less than 1 μm, it becomes difficult to absorb the swell. On the other hand, if the thickness of the swell absorbing layer 5 exceeds 100 μm, refraction increases and distortion of a reflected image increases, which is not preferable. Preferably, the transmittance of the swell absorbing layer 5 is 92% or more. In the present embodiment, the undulation absorbing layer 5 is made of OCA. However, the undulation absorbing layer 5 may be a transparent resin layer that absorbs the undulation of the front surface 4 a of the second polarizing plate 4 and adheres the second polarizing plate 4 and the cover glass 6. Other materials may be used.

  The cover glass 6 is a plate-shaped glass disposed on the front surface 5 a of the swell absorption layer 5. The cover glass 6 has substantially the same shape as the first polarizing plate 2, the liquid crystal unit 3, the second polarizing plate 4, and the undulation absorbing layer 5. The plate thickness of the cover glass 6 can be appropriately set, for example, between about 0.5 to 2.0 mm. The size of the undulation on the front surface 6a and the undulation on the back surface 6b of the cover glass 6 are both less than about 1.0 μm. As shown in FIG. 1, a frame-shaped decorative portion K is formed at a peripheral portion of the front surface 6 a of the cover glass 6. The decorative portion K is colored (for example, black) by printing on the front surface 6a.

  The reflective liquid crystal cell 1 is formed by laminating each layer. After laminating the respective layers, the second polarizing plate 4, the undulation absorbing layer 5, and the cover glass 6 are integrated by a roller unit or a pressing unit (vacuum pressing unit). Further, when forming the undulation absorbing layer 5, a thin layered material may be formed by spraying with a spray so as to be flat.

<Contrast observation>
The reflection images were compared using a schematic example of the reflection type liquid crystal cell 1 and a comparative example. 4A and 4B are diagrams showing a comparative example of comparison observation, in which FIG. 4A is a plan view and FIG. 4B is a cross-sectional view.
FIG. 5 is a diagram showing a schematic example of comparative observation, in which (a) is a plan view and a cross-sectional view.

  As shown in FIGS. 4A and 4B, Comparative Example 10 is configured by laminating the first polarizing plate 2 and the second polarizing plate 4 from the back side. On the other hand, as shown in FIGS. 5A and 5B, in the schematic embodiment 20, the first polarizing plate 2, the second polarizing plate 4, the undulation absorbing layer 5, the cover glass 6, It is composed of For convenience of comparison observation, the liquid crystal unit 3 is not arranged in both the comparative example 10 and the schematic example 20.

  In the comparative observation, Comparative Example 10 and Schematic Example 20 were arranged side by side on a table, and a reflection image of a fluorescent lamp lit on the ceiling was observed. 4A and 5A, the vertically extending bands are the reflected images N1 and N2 of the fluorescent lamp. That is, the reflected images N1 and N2 appearing in Comparative Example 10 and Schematic Example 20 are images of the same fluorescent lamp.

  As shown in FIG. 4A, in Comparative Example 10 in which the undulation absorbing layer 5 and the cover glass 6 are not arranged, the contour of the reflected image N1 of the fluorescent lamp is distorted. In other words, the contour of the reflection image N1 is blurred and blurred. This is considered to be caused by distortion of the reflection image N1 due to undulation and “roughness” of the front surface 4a of the second polarizing plate 4 of Comparative Example 10.

  On the other hand, as shown in FIG. 5A, in the schematic embodiment 20 in which the undulation absorbing layer 5 and the cover glass 6 are arranged, the contour of the reflected image N2 of the fluorescent lamp is not distorted. In other words, the contour of the reflection image N1 is sharp. That is, the undulation and the “roughness” of the front surface 4 a of the second polarizing plate 4 are absorbed by the undulation absorption layer 5, and the front surface 5 a of the undulation absorption layer 5 is also flattened by the cover glass 6. It is considered that the distortion can be reduced.

  According to the reflective liquid crystal cell 1 described above, the undulation and the roughness of the front surface 4a of the second polarizing plate 4 are absorbed by the undulation layer 5, and the front surface 5a of the undulation layer 5 is bonded to the cover glass 6. Therefore, the surface becomes a small flat surface such as undulation. Accordingly, a clear image can be displayed when the reflection type liquid crystal cell 1 is used as a monitor, and distortion of a reflection image when the reflection type liquid crystal cell 1 is used as a mirror can be reduced.

  Further, in the present embodiment, since the frame-shaped decorative portion K is formed on the peripheral portion of the cover glass 6, the design of the reflective liquid crystal cell 1 can be improved. Further, the decorative portion K can cover a frame-shaped dam member provided on the outer peripheral edge of the liquid crystal portion 3, a power supply portion, and a liquid crystal inlet (not shown).

  In addition, the undulation of the second polarizing plate 4 of the present embodiment is larger than the undulation of the first polarizing plate 2. As described above, since the first polarizing plate 2 is a soft material and the undulation is easily reduced, the size of the undulation is less than 1.0 μm.

  On the other hand, the undulation on the front surface of the second polarizing plate (absorption type polarizing plate) is approximately 1.0 μm or more. When the second polarizing plate is simply used for a liquid crystal monitor, the undulation on the front surface of the second polarizing plate does not significantly affect the displayed image because the second polarizing plate only transmits the incident light. Therefore, if the current second polarizing plate is used only for a liquid crystal monitor, even if the undulation on the front surface of the second polarizing plate is 1.0 μm or more, there is no significant effect on the displayed image.

However, when the function as a mirror is realized as in the present embodiment, if the undulation of the second polarizing plate is large, the contour of the reflection image N1 is distorted as shown in FIG. There is a problem that it cannot be used as a mirror. In particular, when used as an electronic mirror of an inner mirror portion of a vehicle, it is desired to clarify a reflected image because it is related to confirmation of the rear of the vehicle.
Here, it is conceivable to reduce the undulation of the second polarizing plate by flattening the front surface and the back surface of the second polarizing plate (absorption-type polarizing plate) by, for example, pressing means or roller means. However, since the second polarizing plate is a harder material than the first polarizing plate, it is difficult to eliminate the undulation on the front surface by pressing means or the like.

  In view of such problems, the present invention has reached the idea of providing the undulation layer 5 to absorb the undulation of the front surface 4a of the second polarizing plate 4. That is, the undulation and the roughness of the front surface 4a of the second polarizing plate 4 are filled by the undulation layer 5. An object of the present invention is a problem peculiar to the present invention which occurs when a reflective liquid crystal cell is used as a mirror.

[Second embodiment]
Next, a reflective liquid crystal cell 1A according to a second embodiment of the present invention will be described. As shown in FIG. 6, the reflection type liquid crystal cell 1A includes a first polarizing plate 2, a liquid crystal unit 3, a second polarizing plate 4, and a swell absorbing layer 5A. That is, the reflective liquid crystal cell 1A differs from the first embodiment in that the cover glass 6 is not provided.

  The first polarizing plate 2, the liquid crystal unit 3, and the second polarizing plate 4 of the reflection type liquid crystal cell 1A are the same as those in the first embodiment. The undulation layer 5A is a transparent resin layer that absorbs the undulation of the front surface 4a of the second polarizing plate 4 and has a flat front surface 5a. The undulation absorbing layer 5A is adhered to the second polarizing plate 4. The front surface 5a of the swell absorbing layer 5A is flattened by eliminating swell by a roller means or a pressing means. The undulation of the front surface 5a is less than 1.0 μm.

  The reflection-type liquid crystal cell 1A according to the second embodiment formed as described above can provide substantially the same effects as those of the first embodiment. That is, as in the second embodiment, the cover glass 6 may be omitted and the swell absorbing layer 5A may be exposed. Even in this case, since the undulation of the front surface 5a of the undulation absorption layer 5A is small and flat, the distortion of the reflected image when the reflective liquid crystal cell 1A is used as a mirror can be reduced. Also, since the second polarizing plate 4 is a relatively hard material, it is difficult to flatten the front surface 4a. However, since the undulation absorbing layer 5A is a relatively soft material, the undulation of the front surface 5a of the undulation absorbing layer 5A. And the flatness can be easily increased. Although not specifically illustrated, contrast observation was performed on the reflective liquid crystal cell 1A according to the second embodiment in the same manner as in the first embodiment, but the reflected image N2 ((a As in the case of)), the reflection image was small in distortion.

  Although the embodiments of the present invention have been described above, design changes can be made as appropriate without departing from the spirit of the present invention. For example, instead of the cover glass 6, a hard coat layer may be provided by applying a coating or the like for suppressing surface reflection.

1 reflective liquid crystal cell 2 first polarizer (reflective polarizer)
3 Liquid crystal part 4 Second polarizer (absorption polarizer)
5 Wave absorption layer 6 Cover glass

FIG. 1 is a perspective view showing a reflective liquid crystal cell and a liquid crystal monitor according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a reflective liquid crystal cell and a liquid crystal monitor according to the first embodiment. It is an expanded sectional view showing the 2nd polarizing plate concerning a first embodiment. It is a figure which shows the comparative example of contrast observation, (a) is a top view and (b) is sectional drawing. It is a figure which shows the model example of contrast observation, (a) is a top view and (b) is a sectional view. It is sectional drawing which shows the reflective liquid crystal cell which concerns on 2nd embodiment.

<Contrast observation>
The reflection images were compared using a schematic example of the reflection type liquid crystal cell 1 and a comparative example. 4A and 4B are diagrams showing a comparative example of comparison observation, in which FIG. 4A is a plan view and FIG. 4B is a cross-sectional view.
5A and 5B are diagrams showing a schematic example of comparative observation, in which FIG. 5A is a plan view and FIG. 5B is a cross-sectional view.

Claims (5)

A first polarizing plate that transmits one of the orthogonal polarization components and reflects the other,
A liquid crystal unit disposed on the front side of the first polarizing plate,
A second polarizing plate disposed on the front side of the liquid crystal unit and transmitting a predetermined polarization component of incident incident light to the liquid crystal unit, and transmitting incident light from the liquid crystal unit,
Disposed on the front surface of the second polarizing plate, a transparent undulation layer made of resin,
A cover glass disposed on the front surface of the swell absorption layer,
The reflection type liquid crystal cell, wherein the undulation layer adheres the second polarizing plate and the cover glass and absorbs undulation on the front surface of the second polarizing plate. A first polarizing plate that transmits one of the orthogonal polarization components and reflects the other,
A liquid crystal unit disposed on the front side of the first polarizing plate,
A second polarizing plate disposed on the front side of the liquid crystal unit and transmitting a predetermined polarization component of incident incident light to the liquid crystal unit, and transmitting incident light from the liquid crystal unit,
Disposed on the front surface of the second polarizing plate, and a transparent undulation layer made of resin,
The reflection type liquid crystal cell, wherein the undulation absorbing layer has a flat front surface and absorbs undulations on the front surface of the second polarizing plate.   3. The reflection type liquid crystal cell according to claim 1, wherein the undulation of the second polarizing plate is larger than the undulation of the first polarizing plate.   2. The reflective liquid crystal cell according to claim 1, wherein a peripheral portion of the cover glass is decorated in a frame shape.   3. The reflection type liquid crystal cell according to claim 1, wherein the undulation layer is formed to have a thickness of 1 to 100 [mu] m.

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