JP2000206523A - Liquid crystal device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to embody a display form of a transmission type using an illumination device 5 of a liquid crystal device of a both surface display type. SOLUTION: This liquid crystal device of the both surface display type is the liquid crystal device having a pair of substrates 3a and 3b facing each other across liquid crystals 6 and displays images from both sides of a pair of these substrates 3a and 3b. Part or the whole of the flanks of a pair of the substrates 3a and 3b is provided with the illumination device 5 for irradiating the same with light. The light from the illumination device 5 propagates in the substrates 3a and 3b and flatly spreads. The images are displayed on both front and rear surfaces of the liquid crystal panel 1A by utilizing the light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling characters or numerals,
The present invention relates to a liquid crystal device that displays an image such as a picture. The present invention also relates to an electronic device including the liquid crystal device.

[0002]

2. Description of the Related Art At present, liquid crystal devices are widely used in electronic devices such as portable telephones and portable information terminals. In many cases, the liquid crystal device is used to display information such as characters, numbers, and patterns.

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 a voltage applied to the liquid crystal. This alignment control modulates light incident on the liquid crystal to perform display. In this liquid crystal device, in many cases, a light reflection layer or a backlight is provided on the back surface of one of the pair of substrates,
An image is displayed on the surface of the substrate facing the image. That is, in many cases, the single-sided display method is used.

Further, as a conventional liquid crystal device, a so-called double-sided display type liquid crystal device has been known, for example, as disclosed in Japanese Patent Application Laid-Open No. Hei 10-198291, in which a display is performed on both front and rear sides of a liquid crystal panel.

[0005]

With respect to the liquid crystal device of the double-sided display method, it is difficult to provide a lighting device because the display is performed using both the front and rear surfaces of the liquid crystal panel.
Only a reflection type using external light such as sunlight or the like can be considered, but a transmission type using an illumination device has not been considered.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to realize a display mode using a lighting device in a double-sided display type liquid crystal device.

[0007]

Means for Solving the Problems (1) In order to achieve the above object, a liquid crystal device according to the present invention is a liquid crystal device having a pair of substrates facing each other with a liquid crystal interposed therebetween. In the liquid crystal device of the double-sided display method of performing display on both sides, illumination means for irradiating light to the side surfaces of the pair of substrates is provided.

In this liquid crystal device, light applied to the side surface of the substrate propagates inside the substrate and spreads in a plane, and display is performed by modulating the light with liquid crystal. Thus, a two-sided transmission type liquid crystal device is realized.

(2) In the liquid crystal device having the above-described structure, the illumination means can be configured to irradiate, for example, light incident from an end face in a line by a light guide member or the like. More specifically, the illumination means can be configured by a light source that emits light, and a light guide member that guides light from the light source to the side surfaces of the pair of substrates. By using this light guide member, uniform light can be supplied to the liquid crystal panel. Also, as lighting means,
It is also possible to use a cold-cathode tube, a device in which LEDs are arranged in a line, and can emit light in a plane.

Regarding each of the above-mentioned lighting means,
It is desirable that the thickness and width of the end face of the liquid crystal panel be equal to or less than the dimension of the light emitting portion. Further, when the light emission dimension on the illumination means side is larger, it is desirable to narrow the emitted light by a slit or a lens.

If the size of the light emitted from the illuminating means is regulated as described above, there is obtained an effect that light does not leak to a portion other than the end face of the glass, light utilization efficiency is increased, and troubles due to stray light do not occur.

(3) In the liquid crystal device having the above configuration,
A light reflection layer can be provided on a surface of the pair of substrates opposite to a surface into which light is introduced. In this way, it is possible to prevent light propagating inside the substrate from meaninglessly radiating outside without contributing to display.

(4) Regarding the liquid crystal device having the above configuration,
Light can be applied to the entire periphery of the side surfaces of the pair of substrates by the illumination means. In this case, a very bright display can be performed in the liquid crystal device of the double-sided display method.

(5) Next, the electronic device according to the present invention
In an electronic apparatus including a liquid crystal device and a housing for accommodating the liquid crystal device, the liquid crystal device includes the liquid crystal device described in any one of (1) to (4). As such an electronic device, for example, a mobile phone, a portable information terminal, or the like can be considered.

[0015]

(First Embodiment) FIG. 1 shows an embodiment of a liquid crystal device according to the present invention. In this liquid crystal device, a lighting device 5 and a liquid crystal driving IC are provided on a liquid crystal panel 1A.
(Not shown). The liquid crystal panel 1A of the present embodiment is a simple matrix type liquid crystal panel that does not use an active element.

The liquid crystal panel 1A has a pair of substrates, the periphery of which is joined by a sealing material 2, that is, a common substrate 3A.
a and the segment substrate 3b. The spacing 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.

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 further formed thereon.
Is formed. On the outer surface of the material substrate 7a, a polarizing plate 11a is attached to almost the entire surface of the material substrate 7a, and further, a first reflection layer 12a is provided in a partial region of the surface of the material substrate 7a.

The segment substrate 3b facing the common substrate 3a has a transparent material substrate 7b. This material substrate 7b
A segment electrode 8b is patterned into a predetermined shape on the inner surface of the substrate, and an alignment film 9b is further formed thereon.
On the outer surface of the material substrate 7b, a polarizing plate 11b is adhered to almost the entire surface of the material substrate 7b.
The second reflective layer 12b is provided in a partial region of the surface of the second reflective layer. The second reflection layer 12b is provided corresponding to a region on the common substrate 3a side where the first reflection layer 12a is not provided.
That is, the first reflection layer 12a and the second reflection layer 12b
They are provided in a relationship complementing each other when viewed in a plan view.

A lighting device 5 is provided on a side surface of the liquid crystal panel 1A. For example, as shown in FIG. 2, the lighting device 5 is provided at a light guide member 13 provided corresponding to one of four sides of the liquid crystal panel 1 </ b> A, and at an end of the light guide member 13. It is formed by the light source 14. Light guide member 13
Has a structure in which light taken in from one end is emitted in a linear shape, and the light emitted in a linear shape is applied to the side surfaces of the pair of material substrates 7a and 7b. In such a structure, for example, in FIG. 1, an appropriate concavo-convex pattern for guiding light in the horizontal direction is formed in a portion 13a corresponding to the side surface of the liquid crystal panel 1A, and a reflective layer 17 is provided in other surface regions. Can be achieved by: In order to prevent the light from the illumination device 5 from being unnecessarily radiated to the outside, it is desirable to provide the light reflection layer 16 at the end opposite to the material substrates 7a and 7b.

The illuminating device 5 is connected to the liquid crystal panel 1A.
It can be arranged not only on the side but also on the entire circumference of the side surface, so that the entire surface of the liquid crystal panel 1A can be uniformly illuminated.

In the above structure, the material substrates 7a and 7
b is 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:
(Indium tin oxide). The alignment films 9a and 9b are formed of, for example, polyimide or the like. As is well known, the polarizing plates 11a and 11b are polarization separating elements having a function of transmitting linearly polarized light directed in a certain direction and not transmitting other polarized light by absorption or the like.

Since the first reflection layer 12a and the second reflection layer 12b are formed of a non-transparent material, in the liquid crystal panel 1A of the present embodiment, the front side of each reflection layer 12a and 12b is the observation side, and the observer The image is confirmed by observing the liquid crystal panel 1A from both the front and back sides indicated by the arrow C. That is, in the present embodiment, an image can be displayed on both the front and back sides of one liquid crystal panel 1A.

Considering the case where a display is made as a reflection type liquid crystal panel using external light such as sunlight, FIG.
As shown in FIG. 1, the first reflection layer 12a and the second reflection layer 12b
Of the liquid crystal panel 1A due to the contrast between the light reflected by the liquid crystal panel and the light absorbed by the polarizing plates 11a and 11b.
The image is displayed on both sides.

In a dark place where external light cannot be used, the light emitted from the illuminating device 5 and guided by the material substrates 7a and 7b in the plane direction causes the liquid crystal panel 1A to emit light.
The image is displayed on both sides.

(Second Embodiment) FIG. 4 shows another embodiment 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 area of the outer surface of the material substrate 7a forming the common substrate 3a and the entire area of the outer surface of the material substrate 7b forming the segment substrate 3b. , Respectively, the reflection polarizer 2
1a, 21b and their reflective polarizers 21
a, a polarizing plate 22
a, 22b were stuck.

The following is a description of the reflective polarizers 21a and 21b. While a general polarizing plate has a function of transmitting linearly polarized light directed in a certain direction and not transmitting other polarized light by absorption or dispersion, etc., these reflective polarizers 21a and 21b are
It has the function of transmitting linearly polarized light in one direction and reflecting the other linearly polarized light. In particular, linearly polarized light perpendicular to the transmission polarization axis is totally reflected.

Such reflective polarizers are disclosed in international published applications (International Application No. WO 95/17692 or W
O95 / 27919), a polarization separation film having a structure in which a number of thin films are stacked, a polarization separation plate having a structure in which a (1/4) λ plate is disposed on both sides or one side of a cholesteric liquid crystal layer, A polarization separation member (SID 92 DIGEST, pp. 427 to 42) that separates reflected polarized light and transmitted polarized light using Brewster's angle.
9) or a polarization separating member using a hologram.

The reflective polarizers 21a and 21b have a multilayer structure formed by alternately laminating two types of layers A and B, as shown in FIG. 5, for example. , B, the two layers adjacent to each other in the laminating direction have the same refractive index in one direction between them, and the refractive index in the direction perpendicular thereto is different between the two layers. The thickness of the layer varies.

In FIG. 5, when considering the three orthogonal XYZ directions, the two layers A and B are formed in a multilayer state by, for example, extrusion molding, and are further formed in one direction (for example, the X direction).
, And not in the other direction (ie, the Y direction). That is, the X-axis direction is the stretching direction, and the Y-axis direction is the transverse direction to it. B
The material has a refractive index n _S (eg, n _S = 1.64);
This is not substantially changed by the stretching process. on the other hand,
The material A has a characteristic that the refractive index changes by the stretching process. For example, when a sheet made of the material A is stretched in a uniaxial direction, the sheet has one refractive index n _AX (for example, n _AX = 1.88) in the stretching direction (that is, the X direction), and has a transverse direction (that is, Y Direction) has a different refractive index n _AY (eg, n _AY = 1.64).

When the laminated structure of FIG. 5 made of the materials A and B 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, in the Y direction perpendicular to the direction, 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 enters the reflective polarizer, the polarized component (a) in the direction of the transmission axis E of the incident light passes through the reflective polarizer. On the other hand,
The polarization component (b) of the incident light in the direction of the light absorption axis F faces the refractive index difference Δn, and is therefore reflected at that part.

Further, the layer thicknesses t1, t2, A, B between the respective layers
At t3,……… the dimensions are changed little by little,
Therefore, as shown in FIG. 6, light (b-1), (b-2),... Having different wavelengths can be reflected at the boundary surface between the layers. That is, A, B having different layer thicknesses
With two types of multilayer structures, it is possible to efficiently reflect light including all types of wavelengths.

Incidentally, the layer thicknesses t1, t2, t3 of each layer
... Are combined so as to reflect light of all wavelengths, the finally obtained reflected light becomes white light. On the other hand, the layer thicknesses t1, t2, t3,.
Is set to an appropriate combination, only light of a desired wavelength, that is, light of a desired color can be selectively reflected by the reflective polarizer.

In this embodiment, as shown in FIG. 7, the reflective polarizers 21a and 21a extend over the entire surface of the liquid crystal panel 1B.
By contrast between the light reflected by b and the light transmitted by the liquid crystal panel 1B, an image can be displayed on both the front and back surfaces over the entire surface of the liquid crystal panel 1B. In a dark place where external light cannot be used, an image is displayed on both the front and back surfaces of the liquid crystal panel 1B by light emitted from the lighting device 5 and guided in a plane direction by the material substrates 7a and 7b.

(Third Embodiment) FIG. 8 shows still another embodiment 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 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 electrode 23a is formed of Al (aluminum) or the like in a partial area of the inner surface of the common substrate 3a, and A is formed in a partial area of the inner surface of the segment substrate 3b.
The inner electrode 23b is formed by l or the like. Inner electrode 23
a and 23b are provided in a region where no opponent is provided, that is, in a relationship in which the positions complement each other when viewed in plan.

Then, the polarizing plate 11b is attached to the outer surface of the segment substrate 3b so as to face the inner electrode 23a on the mating substrate 3a. Further, a polarizing plate 11a is attached on the outer surface of the common substrate 3a so as to face the inner electrode 23b on the counterpart substrate 3b.

In this embodiment, since the inner electrodes 23a and 23b are partially provided for the respective substrates 3a and 3b, a step corresponding to the inner electrodes 23a and 23b is formed in the cell gap G. However, the size of the cell gap G itself is kept constant over the entire surface of the liquid crystal panel 1C.

In the embodiment shown in FIG. 1, the liquid crystal panel 1
There are two polarizing plates 11a and 11b in total, one on each of the front and back surfaces of A. On the other hand, in the present embodiment shown in FIG. 8, one polarizing plate 1 is provided for one inner surface electrode 23a.
1b, and one polarizing plate 11a exists for the other inner surface electrode 23b. According to this panel structure, the attenuation of light passing through this panel can be reduced by an amount equal to the number of polarizing plates reduced by one in each region, and thus a bright display can be obtained.

In this embodiment, the inner electrodes 23a and 23b
Is the observation side, and the observer can check the display from both the front and back sides of the liquid crystal panel 1C according to the arrow C.
In a case where external light is used in the present embodiment, as shown in FIG.
The display on one of the front and back sides is performed by the contrast between the light reflected by a and transmitted through the polarizing plate 11b and the light absorbed by the polarizing plate 11b.

On the other hand, in the other area shown on the left side of the drawing, the contrast between the light reflected by the inner electrode 23b and transmitted through the polarizing plate 11a and the light absorbed by the polarizing plate 11a causes the other side to be opposite. Is displayed.

In a dark place where external light cannot be used, the light emitted from the illuminating device 5 and guided by the material substrates 7a and 7b in the plane direction causes the liquid crystal panel 1C to emit light.
Are displayed on both sides.

(Fourth Embodiment) FIG. 10 shows a portable information terminal which is an embodiment of an electronic apparatus according to the present invention. The portable information terminal 26 has a first housing 27 and a second housing 28. The second housing 28 can be opened and closed with respect to the first housing 27 as shown in FIGS. 11 and 10, and a liquid crystal device 29 is housed inside 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. 4), and the liquid crystal panel 1C (FIG. 8).

As shown in FIG. 10, an opening, that is, a window 31 is formed on the surface of the second housing 28, and a part of the surface of the liquid crystal device 29 is exposed to the outside through the window 31. As shown in FIG. 11, 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 is exposed to the outside through the window 32. Reference numeral 33 indicates a keyboard switch.

If a 7-segment display is performed on the front side of the liquid crystal device 29 and a dot matrix display is performed on the back side of the liquid crystal device 29, the 7-segment display is performed through the window 31 with the portable information terminal 26 closed. The display is visible. Further, the dot matrix display can be visually recognized through the window 32 with the portable information terminal 26 opened.

(Other Embodiments) Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the embodiments, and various modifications may be made within the scope of the invention described in the claims. Can be modified.

For example, the present invention is not limited to a simple matrix type liquid crystal panel, but includes a TFT (Thin Film Transistor).
r), an active matrix type liquid crystal panel having a structure in which a non-linear element such as TFD (Thin Film Diode) is used as an active element. Further, the electronic device according to the present invention is not limited to a portable information terminal, but may be a mobile phone or any other electronic device.

[0047]

According to the liquid crystal device and the electronic apparatus according to the present invention, the light applied to the side surface of the substrate propagates inside the substrate and spreads in a plane, and this light is modulated by the liquid crystal to display. It can be performed. Thereby, a double-sided transmission type liquid crystal device having a structure in which images are displayed on both front and rear surfaces of the liquid crystal panel using light from the illumination device can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a cross-sectional structure of an embodiment of a liquid crystal device according to the present invention.

FIG. 2 is a perspective view showing the overall appearance of the liquid crystal device of FIG.

FIG. 3 is a cross-sectional view schematically showing a display state of the liquid crystal device of FIG.

FIG. 4 is a sectional view showing a sectional structure of another embodiment of the liquid crystal device according to the present invention.

FIG. 5 is a perspective view schematically showing an example of the structure of a reflective polarizer.

FIG. 6 is a diagram for explaining the function of the reflective polarizer of FIG. 5;

7 is a cross-sectional view schematically illustrating a display state of the liquid crystal device of FIG.

FIG. 8 is a sectional view showing a sectional structure of still another embodiment of the liquid crystal device according to the present invention.

9 is a cross-sectional view schematically illustrating a display state of the liquid crystal device of FIG.

FIG. 10 is a perspective view showing a portable information terminal which is an embodiment of the electronic device according to the present invention.

FIG. 11 is a perspective view showing a state where a housing of the portable information terminal of FIG. 10 is opened.

[Explanation of symbols]

 1A, 1B, 1C Liquid crystal panel 2 Sealing material 3a Common substrate 3b Segment substrate 4 Spacer 5 Lighting device 6 Liquid crystal 7a, 7b Material substrate 8a Common electrode 8b Segment electrode 9a, 9b Alignment film 11a, 11b Polarizing plate 12a First reflection layer 12b Second reflective layer 13 Light guide member 13a Light scattering portion 14 Light source 16 Light reflective layer 17 Light reflective layer 21a, 21b Reflective polarizer 22a, 22b Polarizer 23a, 23b Inner electrode E Transmission axis F Absorption axis G Cell gap

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Seichi Iino 3-3-5 Yamato, Suwa-shi, Nagano F-term in Seiko Epson Corporation (reference) 2H091 FA08X FA08Z FA14Z FA23Z FA41Z FC08 FD08 FD15 GA01 GA13 KA01 LA13 LA30

Claims (5)

[Claims] 1. A double-sided display type liquid crystal device having a pair of substrates opposed to each other with a liquid crystal interposed therebetween and performing display on both surfaces of the pair of substrates, and illuminating means for irradiating side surfaces of the pair of substrates with light. A liquid crystal device comprising: 2. The liquid crystal device according to claim 1, wherein the illuminating means includes a light source that emits light, and a light guide member that guides light from the light source to side surfaces of the pair of substrates. 3. The liquid crystal device according to claim 1, wherein a light reflecting layer is provided on a side surface of the pair of substrates opposite to a surface on which light is introduced. 4. The liquid crystal device according to claim 1, wherein the illuminating unit irradiates the entire periphery of the side surfaces of the pair of substrates with light. 5. An electronic apparatus having a liquid crystal device and a housing for accommodating the liquid crystal device, wherein the liquid crystal device is constituted by the liquid crystal device according to at least one of claims 1 to 4. Electronic equipment characterized by the above.