JP3731362B2 - Liquid crystal device and electronic device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal device that displays images such as letters, numbers, and patterns by controlling the orientation of liquid crystal sealed between a pair of substrates. The present invention also relates to an electronic apparatus configured using the liquid crystal device.
[0002]
[Prior art]
Currently, liquid crystal devices are widely used in electronic devices such as mobile phones and portable information terminals. In many cases, the liquid crystal device is used to display information such as letters, numbers, and pictures.
[0003]
This liquid crystal device generally has a liquid crystal sandwiched between a pair of substrates, and controls the orientation of the liquid crystal by controlling the voltage applied to the liquid crystal, thereby modulating the light incident on the liquid crystal. Some liquid crystal devices display information such as characters in color. In such a liquid crystal device, a color filter is provided on one surface of a pair of substrates. In a conventional liquid crystal device having a structure using a color filter, in many cases, the color filter is provided over the entire surface of the substrate.
[0004]
Further, as a conventional liquid crystal device, a liquid crystal device having a structure in which a color filter is provided in a partial region of the entire planar area of a liquid crystal panel is known as disclosed in, for example, JP-A-10-198291.
[0005]
[Problems to be solved by the invention]
A conventional liquid crystal device having a structure in which a color filter is provided on the entire surface of a substrate has a problem that both a color display area and a black and white display area cannot be displayed on the surface of one liquid crystal panel.
[0006]
In addition, regarding a conventional liquid crystal device having a structure in which a color filter is provided in a partial area of a liquid crystal panel, it seems that black and white display can be performed in addition to color display by setting an area where no color filter is provided. However, in reality, the actual situation is that the monochrome display cannot be performed properly. The reason is considered that a difference occurs in the cell gap between the region where the color filter is provided and the region where the color filter is not provided, so that the driving conditions relating to the liquid crystal are different between these regions. For example, a change occurs in the appropriate amount of the chiral agent mixed in the liquid crystal between a plurality of regions having a difference in the cell gap, so that the liquid crystal cannot be driven properly in all the regions.
[0007]
The present invention has been made in view of the above problems, and an object of the present invention is to ensure that both color display and monochrome display can be realized with a single liquid crystal panel.
[0008]
[Means for Solving the Problems]
(1) In order to achieve the above object, a liquid crystal device according to the present invention includes a pair of substrates facing each other with a liquid crystal interposed therebetween, and at least one of the substrates has a colored layer and a transparent layer in the same plane. The colored layer and the transparent layer have substantially the same height, and the liquid crystal device is a double-sided display type liquid crystal device, which displays through the colored layer on one substrate side and on the other substrate side Display is performed through the transparent layer, and a first reflective layer provided in a partial region on either the inside or outside of the first substrate of the pair of substrates, and the first reflection of the outside of the first substrate. A first polarizing plate provided in a region where no layer is provided, and a second reflective layer provided to face the first polarizing plate either inside or outside the second substrate facing the first substrate And on the outside of the second substrate It has the 2nd polarizing plate provided facing the 1st reflection layer, It is characterized by the above-mentioned.
[0009]
Here, “substantial” means that even if a slight error occurs due to a manufacturing error or the like, such an error is included when the same effect can be obtained.
[0010]
According to the liquid crystal device having the above-described configuration, even when the colored layer is provided in a partial region of the substrate and the colored layer is not provided in another region, the transparent layer having the same height as the colored layer is provided in that region. Therefore, the cell gap can be maintained uniformly over the entire surface of the liquid crystal panel. As a result, the driving conditions relating to the liquid crystal can be maintained at the same conditions between the colored layer and the non-colored layer, so that both color display and monochrome display can be realized on one liquid crystal panel without any problem.
[0011]
(2) As a liquid crystal device, a single-sided display type liquid crystal device that performs display from only one side of a pair of substrates, a double-sided display type liquid crystal device that performs display from both of a pair of substrates, and the like are known. In a double-sided display type liquid crystal device, it is conceivable to adopt a display form in which color display is performed on one surface and monochrome display is performed on the opposite surface. When the present invention having the above-described configuration is applied to such a liquid crystal device, color display can be performed from one substrate through the colored layer, and monochrome display can be performed from the other substrate through the transparent layer. In this case, if the structure of the present invention is used, a constant cell gap can be maintained between the colored layer and the transparent layer, so that both color display and monochrome display can be clearly formed.
[0012]
(3) In the above-described double-sided display type liquid crystal device, for example, a polarizing plate is provided on each outer surface of a pair of substrates, and a partial region of the outer surface of the polarizing plate provided on one substrate is used. It can be configured by providing the first reflective layer and providing the second reflective layer in a region other than the region facing the first reflective layer on the outer surface of the polarizing plate provided on the other substrate.
[0013]
(4) In addition, the above-described liquid crystal device of the double-sided display type is configured, for example, by providing a reflective polarizer on each outer surface of a pair of substrates and further providing a polarizing plate outside the reflective polarizer. it can. When this reflective polarizer is used, a color display corresponding to the colored layer can be displayed on both the front and back surfaces, and a monochrome display corresponding to the transparent layer can also be displayed on both the front and back surfaces.
[0014]
The reflective polarizer will be described as follows. While a general polarizing plate has a function of transmitting linearly polarized light directed in one direction and not transmitting other polarized light by absorption, dispersion, etc., this reflective polarizer is linearly polarized light in a certain direction. And linearly polarized light other than that are reflected, and in particular, linearly polarized light in a direction perpendicular to the transmission polarization axis is totally reflected.
[0015]
Such reflective polarizers include: (1) a polarized light separation film having a structure in which a large number of thin films are laminated, as disclosed in an internationally published international application (international application number WO95 / 17692 or WO95 / 27919); 2) Polarization separation plate with a (1/4) λ plate on either side or one side of the cholesteric liquid crystal layer, and (3) A structure that separates into reflected and transmitted polarized light using the angle of Brewster. It can be configured using a polarized light separating member (SID 92 DIGEST, pages 427 to 429) or (4) a polarized light separating member using a hologram.
[0016]
For example, as shown in FIG. 5, the reflective polarizer has a multi-layer structure formed by alternately laminating two types of layers A and B, and the laminating direction of the multi-layers A and B is the same. In two layers adjacent to each other, the refractive index in one direction is set to be equal between the two layers, the refractive index in the direction perpendicular thereto is set to be different between the two layers, and the layer thickness of each layer varies. It is
[0017]
In FIG. 5, when considering XYZ orthogonal three-axis directions, two layers A and B are formed in a multilayer state by, for example, extrusion molding, and further stretched along one direction (for example, the X direction). It is not stretched in one direction (that is, the Y direction). That is, the X-axis direction is the stretching direction, and the Y-axis direction is the transverse direction thereto. B material has refractive index n _S (For example, n _S = 1.64), which is substantially unchanged by the stretching process. On the other hand, A material has the characteristic that a refractive index changes with extending | stretching processes. For example, when a sheet made of material A is stretched in a uniaxial direction, one refractive index n _{AX in the} stretching direction (that is, the X direction). (For example, n _AX = 1.88) with different refractive indices n _{AY in the} lateral direction (ie Y direction) (For example, n _AY = 1.64).
[0018]
If the laminated structure of FIG. 5 made of A and B materials is stretched in the X direction, a large refractive index difference Δn = 1.88−1.64 = 0.24 is generated in the stretching direction. On the other hand, with respect to the Y direction perpendicular thereto, the refractive index difference Δn = 1.64-1.64 = 0 between the A and B layers, and there is no difference in the refractive index. Due to such optical characteristics, when light is incident on the reflective polarizer, the polarization component (a) in the direction of the transmission axis E of the incident light is transmitted through the reflective polarizer. On the other hand, the polarization component (b) of the incident light in the direction of the absorption axis F faces the refractive index difference Δn, and is therefore reflected at that portion.
[0019]
Further, the layer thicknesses t1, t2, t3,... Between the layers A and B are slightly changed in size, and therefore light having different wavelengths (b) at the interface between the layers as shown in FIG. -1), (b-2),... Can be reflected. That is, A and B types of multilayer structures with different layer thicknesses can efficiently reflect light including all types of wavelengths.
[0020]
By the way, if the layer thicknesses t1, t2, t3,... Of each layer are combined to such a thickness that reflects light of all wavelengths, the finally obtained reflected light is white light. On the other hand, if the layer thicknesses t1, t2, t3,... Are set to an appropriate combination, only a desired wavelength, that is, light of a desired color can be selectively reflected by the reflective polarizer.
[0021]
(5) Further, the above-described double-sided display type liquid crystal device includes, for example, a first reflective layer provided in a partial region on the inner or outer surface of the first substrate of the pair of substrates. A first polarizing plate is provided in a region of the outer surface of one substrate where the first reflective layer is not provided, and the first polarizing plate is provided on the inner or outer surface of the second substrate facing the first substrate. A second reflective layer is provided so as to face the first substrate, and a second polarizing plate is provided on the outer surface of the second substrate so as to face the first reflective layer.
[0022]
(6) Next, an electronic apparatus according to the present invention is an electronic apparatus having a liquid crystal device and a housing for housing the liquid crystal device, wherein the liquid crystal device is configured by the liquid crystal devices having various configurations described above. Features. As such an electronic device, for example, a portable information terminal, a mobile phone, and the like can be considered.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
FIG. 1 shows an embodiment of a liquid crystal panel which is a main part of a liquid crystal device according to the present invention. The liquid crystal device is formed by attaching ancillary equipment such as a liquid crystal driving IC and a lighting device to the liquid crystal panel 1A. The liquid crystal panel 1A of the present embodiment is a simple matrix type liquid crystal panel that does not use active elements.
[0024]
The liquid crystal panel 1A includes a pair of substrates whose periphery is bonded by a sealing material 2, that is, a common substrate 3a and a segment substrate 3b. The distance between these substrates, the so-called cell gap G, is maintained at a constant size by the spacer 4, and the liquid crystal 6 is sealed in the cell gap.
[0025]
The common substrate 3a has a transparent material substrate 7a. A common electrode 8a is patterned into a predetermined shape on the inner surface of the material substrate 7a, and an alignment film 9a is formed thereon. Further, on the outer surface of the material substrate 7a, a polarizing plate 11a is attached to almost the entire surface, and a first reflective layer 12a is provided in a partial region of the surface of the material substrate 7a.
[0026]
The segment substrate 3b facing the common substrate 3a has a transparent material substrate 7b. A colored layer so-called color filter 13 is formed in a partial region of the inner surface of the material substrate 7b, and a transparent layer 16 is formed in the same plane as the color filter 13. The color filter 13 is formed in a region facing the first reflective layer 12 a formed on the common substrate 3 a facing the color filter 13, and between the color portions 17 arranged in a dot matrix and between the color portions 17. And the black matrix 18 arranged in the same manner. The color portion 17 is formed by arranging R (red), G (green), and B (blue) colors in a mosaic shape, a delta shape, a stripe shape, or the like.
[0027]
The transparent layer 16 is provided in an area on the inner surface of the segment substrate 3 b where the color filter 13 is not provided, and is arranged between the transparent portions 19 formed of a transparent material and the transparent portions 19. It is formed by the black matrix 18. The transparent layer 16 is formed so that its height is the same as that of the color filter 13.
[0028]
A smooth layer 14 is formed on the color filter 13 and the transparent layer 16, and a segment electrode 8b is patterned into a predetermined shape thereon, and an alignment film 9b is further formed thereon.
[0029]
A polarizing plate 11b is attached to the outer surface of the material substrate 7b constituting the segment substrate 3b, and a second reflective layer 12b is provided in a partial region of the surface of the material substrate 7b. The second reflective layer 12b is provided corresponding to the transparent layer 16, and as a result, provided corresponding to a region where the first reflective layer 12a on the common substrate 3a side is not provided. That is, the first reflective layer 12a and the second reflective layer 12b are provided so as to complement each other in plan view.
[0030]
In the above configuration, the material substrates 7a and 7b are formed of a transparent material such as glass or plastic. The common electrode 8a and the segment electrode 8b are made of, for example, ITO (Indium Tin Oxide). The alignment films 9a and 9b are made of, for example, polyimide. Further, as is well known, the polarizing plates 11a and 11b are polarization separation elements having a function of transmitting linearly polarized light directed in one direction and not transmitting other polarized light by absorption or the like.
[0031]
Since the first reflective layer 12a and the second reflective layer 12b are formed of a non-transparent material, in the liquid crystal panel 1A of the present embodiment, the front side of each reflective layer 12a and 12b is the observation side, and the observer is in the direction of arrow C The image is confirmed by observing the liquid crystal panel 1A. That is, in this embodiment, images can be displayed on both the front and back sides of one liquid crystal panel 1A.
[0032]
Specifically, as shown in FIG. 2, an image is displayed by the contrast between the light reflected by the first reflective layer 12a and the second reflective layer 12b and the light absorbed by the polarizing plates 11a and 11b. In particular, color display is performed in the region CL where the color filter 13 is provided, while monochrome display is performed in the region MN where the transparent layer 16 is provided.
[0033]
In this embodiment, since the height of the color filter 13 and the height of the transparent layer 16 are set to be equal to each other, the cell gap G is maintained uniformly over the entire surface of the liquid crystal panel 1A. For this reason, the conditions required when driving the liquid crystal, such as the appropriate amount of the chiral agent, can be kept constant over the entire surface of the liquid crystal panel 1A. Therefore, both color display and black and white display are clearly displayed under appropriate conditions. it can.
[0034]
(Second Embodiment)
FIG. 3 shows another embodiment of the liquid crystal panel which is the main part of the liquid crystal device according to the present invention. In this figure, the same members as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The liquid crystal panel 1B according to the present embodiment is different from the liquid crystal panel 1A shown in FIG. 1 in that the entire outer surface of the material substrate 7a constituting the common substrate 3a and the entire outer surface of the material substrate 7b constituting the segment substrate 3b. In addition, the reflective polarizers 21a and 21b are provided, and the polarizing plates 22a and 22b are attached to the entire outer surfaces of the reflective polarizers 21a and 21b, respectively. As the reflective polarizers 21a and 21b, film-like reflective polarizers having the structures shown in FIGS. 5 and 6 can be used.
[0035]
In the present embodiment, as shown in FIG. 4, regardless of which region is the region CL where the color filter 13 is provided or the region MN where the transparent layer 16 is provided, the light is reflected by the reflective polarizers 21a and 21b. The image can be displayed on both the front and back sides over the entire surface of the liquid crystal panel 1B by the contrast between the light to be transmitted and the light transmitted through the liquid crystal panel 1B. Of course, color display is performed in the region CL where the color filter 13 is provided, while monochrome display is performed in the region MN where the transparent layer 16 is provided.
[0036]
Also in this embodiment, the height of the color filter 13 and the height of the transparent layer 16 are set to be equal to each other, so that the cell gap G is maintained uniformly over the entire surface of the liquid crystal panel 1B. For this reason, the conditions required when driving the liquid crystal, such as the appropriate amount of chiral agent, can be kept constant over the entire surface of the liquid crystal panel 1B. Therefore, both color display and monochrome display are clearly displayed under appropriate conditions. it can.
[0037]
(Third embodiment)
FIG. 7 shows still another embodiment of a liquid crystal panel which is a main part of the liquid crystal device according to the present invention. In this figure, the same members as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0038]
The liquid crystal panel 1C according to the present embodiment differs from the liquid crystal panel 1A shown in FIG. 1 in the following points. That is, the inner surface electrode 23a is formed of Al (aluminum) or the like on the inner surface of the common substrate 3a corresponding to the region CL where the color filter 13 is provided, and the segment substrate corresponding to the region MN where the transparent layer 16 is provided. Similarly, an inner surface electrode 23b is formed of Al or the like on the inner surface of 3b. Then, the polarizing plate 11b is attached to the color filter region CL on the outer surface of the segment substrate 3b, and further, the polarizing plate 11a is attached to the transparent layer region MN on the outer surface of the common substrate 3a.
[0039]
In this embodiment, since the inner surface electrodes 23a and 23b are partially provided for the substrates 3a and 3b, a step corresponding to the cell gap G is formed. However, in this embodiment as well, the color filter 13 and the transparent layer 16 are set at the same height, so the size of the cell gap G itself is maintained constant over the entire surface of the liquid crystal panel 1C.
[0040]
In the embodiment shown in FIG. 1, two polarizing plates 11a and 11b exist in both the color filter region CL and the transparent layer region MN. On the other hand, in this embodiment shown in FIG. 7, one polarizing plate 11b exists in the color filter region CL, and one polarizing plate 11a also exists in the transparent layer region MN. According to this panel structure, the attenuation of light passing through this panel can be reduced by the amount corresponding to the reduction of the number of polarizing plates by 1, so that a bright display can be obtained.
[0041]
In the present embodiment, the side facing the inner surface electrodes 23a and 23b is the observation side, and the observer can confirm the display from both the front and back sides according to the arrow C. In the present embodiment, as shown in FIG. 8, in the region CL where the color filter 13 is provided, the light reflected by the inner surface electrode 23a and transmitted through the polarizing plate 11b, and the light absorbed by the polarizing plate 11b Color display is performed by the contrast between the two. On the other hand, in the region MN provided with the transparent layer 16, monochrome display is performed by the contrast between the light reflected by the inner surface electrode 23b and transmitted through the polarizing plate 11a and the light absorbed by the polarizing plate 11a. .
[0042]
Also in this embodiment, the height of the color filter 13 and the height of the transparent layer 16 are set to be equal to each other, so that the cell gap G is maintained uniformly over the entire surface of the liquid crystal panel 1C. For this reason, the conditions required when driving the liquid crystal, such as the appropriate amount of chiral agent, can be kept constant over the entire surface of the liquid crystal panel 1C. Therefore, both color display and monochrome display are clearly displayed under appropriate conditions. it can.
[0043]
(Fourth embodiment)
FIG. 9 shows a portable information terminal as an embodiment of the electronic apparatus according to the present invention. The portable information terminal 26 has a first housing 27 and a second housing 28. As shown in FIGS. 10 and 9, the second housing 28 can be opened and closed with respect to the first housing 27, and the liquid crystal device 29 is accommodated in the second housing 28. The liquid crystal device 29 can be configured using, for example, any one of the liquid crystal panel 1A (FIG. 1), the liquid crystal panel 1B (FIG. 3), and the liquid crystal panel 1C (FIG. 7).
[0044]
As shown in FIG. 9, an opening, that is, a window 31 is formed on the surface of the second housing 28, and a part of the surface side of the liquid crystal device 29, for example, the transparent layer region MN is exposed to the outside through the window 31. As shown in FIG. 10, an opening, that is, a window 32 is also formed on the back surface of the second housing 28, and a part of the back surface side of the liquid crystal device 29, for example, the color filter region CL is exposed outside through the window 32. To do. Reference numeral 33 denotes a keyboard switch.
[0045]
If the 7-segment display is performed in the transparent layer region MN and the dot matrix display is performed in the color filter region CL, the 7-segment monochrome display can be visually recognized through the window 31 with the portable information terminal 26 closed. Further, the color display of the dot matrix display can be visually recognized through the window 32 with the portable information terminal 26 opened.
[0046]
(Other embodiments)
The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the embodiments, and various modifications can be made within the scope of the invention described in the claims.
[0047]
For example, each of the liquid crystal panels shown in FIGS. 1, 3 and 7 is a double-sided display type liquid crystal panel having a structure for displaying on both sides, but the present invention is an ordinary liquid crystal panel having a structure for displaying on one side. It can also be applied to.
[0048]
Further, the present invention is not limited to a simple matrix type liquid crystal panel, and is also applied to an active matrix type liquid crystal panel having a structure in which a nonlinear element such as a TFT (Thin Film Transistor), a TFD (Thin Film Diode), or the like is used as an active element. it can.
[0049]
The electronic device according to the present invention is not limited to a portable information terminal, and may be a mobile phone or any other electronic device.
[0050]
【The invention's effect】
According to the liquid crystal device and the electronic apparatus according to the present invention, in the liquid crystal device having a structure in which a colored layer is provided on a part of the substrate surface of the liquid crystal panel, the transparent layer is provided in a region where the colored layer is not provided, and Since the height of the colored layer is the same as the height of the colored layer, the size of the cell gap can be made uniform over the entire surface of the liquid crystal panel. As a result, both color display and black and white display can be reliably realized by one liquid crystal panel.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of an embodiment of a liquid crystal device according to the present invention.
2 is a cross-sectional view schematically showing a display state related to the liquid crystal device of FIG. 1. FIG.
FIG. 3 is a cross-sectional view showing a main part of another embodiment of the liquid crystal device according to the present invention.
4 is a cross-sectional view schematically showing a display state related to the liquid crystal device of FIG. 3. FIG.
FIG. 5 is a perspective view schematically showing a structure of an example of a reflective polarizer.
6 is a diagram for explaining the function of the reflective polarizer of FIG. 5;
FIG. 7 is a cross-sectional view showing a main part of still another embodiment of the liquid crystal device according to the present invention.
8 is a cross-sectional view schematically showing a display state related to the liquid crystal device of FIG.
FIG. 9 is a perspective view showing a portable information terminal which is an embodiment of the electronic apparatus according to the invention.
10 is a perspective view illustrating a state in which a housing of the portable information terminal of FIG. 9 is opened.
[Explanation of symbols]
1A, 1B, 1C Liquid crystal panel 2 Sealing material 3a Common substrate 3b Segment substrate 4 Spacer 6 Liquid crystal 7a, 7b Material substrate 8a Common electrode 8b Segment electrodes 9a, 9b Alignment films 11a, 11b Polarizing plate 12a First reflection layer 12b Second reflection Layer 13 Color filter (colored layer)
16 Transparent layer 17 Color portion 18 Black matrix 19 Transparent portions 21a and 21b Reflective polarizers 22a and 22b Polarizing plates 23a and 23b Inner surface electrode E Transmission axis F Absorption axis G Cell gap

Claims (2)

In a liquid crystal device having a pair of substrates facing each other across the liquid crystal, at least one substrate has a colored layer and a transparent layer in the same plane, and the colored layer and the transparent layer are substantially the same height,
The liquid crystal device is a double-sided display type liquid crystal device, performs display through the colored layer on one substrate side, performs display through the transparent layer on the other substrate side,
A first reflective layer provided in a partial region on either the inside or the outside of the first substrate of the pair of substrates;
A first polarizing plate provided in a region of the outside of the first substrate where the first reflective layer is not provided;
A second reflective layer provided opposite to the first polarizer on either the inside or outside of the second substrate facing the first substrate;
A liquid crystal device comprising: a second polarizing plate provided on the outer side of the second substrate so as to face the first reflective layer. In an electronic apparatus having a liquid crystal device and a housing for housing the liquid crystal device,
An electronic apparatus comprising the liquid crystal device according to claim 1.

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