JP2001092383A - Terminal for electronic book - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection type liquid crystal display of high display quality suitable for an electronic book terminal. SOLUTION: In the electronic book terminal having a display device which displays digital information recorded in an external recording medium housed in the device, the display device is a liquid crystal display device using a polymer film as a substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor memory device, a PC card, a smart media, a CD
An electronic book terminal having a display device for displaying digital information recorded on an external recording medium such as an optical storage disk such as a ROM and a magnetic storage disk such as an MO, and a liquid crystal display device in which the substrate is a plastic substrate, particularly as a display device The present invention relates to an e-book terminal using the same. The PC card refers to the Japan Electronics Industry Promotion Association (JEIDA) and the United States PC Memory Card International.
Tional Association (PCMCI
PC Card Stan, enacted by A)
Dard (JEIDA / PCMCIA).

[0002] An electronic book is a general term for a digitalized version of a book. At present, only books that have been recorded on a recording medium such as a CD-ROM have become widespread. There is also. However, in recent years, the information communication system has also changed dramatically, such as the explosive spread of the Internet, the performance improvement of personal computers, the spread of cable television, and the start of communication satellite services. It is said that such a change in the social environment may cause a change in the distribution form of conventional magazines and books. In the fall of last year, an e-book consortium (E-Book Japan) consisting of hundreds of companies in Japan was established, and the contents of e-books and terminal devices for displaying e-books are being studied.

[0003]

2. Description of the Related Art In a conventional electronic book, a personal computer or a dedicated display terminal is used to display information recorded in the electronic book. CD-ROM
Dedicated terminals with playback devices are very heavy and have poor portability. In addition, a dedicated terminal without a CD-ROM playback device requires a personal computer to store data in the terminal, which is inconvenient. In many cases, a monochrome simple matrix type liquid crystal display is used for the display unit of the dedicated terminal, and the display quality is not satisfactory. For this reason, most books sold as electronic books are limited to contents such as dictionaries or games.

[0004]

A notebook personal computer uses a transmission type active matrix type liquid crystal display device, but a transmission type panel requires a backlight and is used for electronic books where portability is important. Not suitable for terminals. For this reason, most of the conventional electronic book terminal devices use a reflection type liquid crystal display device for the display unit. FIG. 1 shows a sectional structural view of a conventional reflective liquid crystal display device. In a reflection type liquid crystal display device, since a glass substrate of a liquid crystal cell exists between a liquid crystal layer serving as an optical shutter and a reflection plate, parallax is generated between a real image by the liquid crystal and a virtual image by the reflection plate, so that a display image is generated. Shadows will occur.
Further, there is a viewing angle characteristic peculiar to the liquid crystal display device, and there is a disadvantage that the display contrast greatly changes depending on the angle between the display screen and the user's line of sight. As a result,
The display quality of the conventional electronic book terminal device is not satisfactory to the user. An object of the present invention is to provide a reflective liquid crystal display device of high display quality suitable for an electronic book terminal.

[0005]

A display device for an electronic book terminal device is required to be thin, light in weight, small in power consumption, and excellent in display quality.
Liquid crystal, electroluminescence (EL), electrochromic (EC), thermochromic (TC), field emission (FED) as thin display devices
Etc. At present, none of the above requirements are completely satisfied, and a liquid crystal display device is considered to be the most suitable. However, as described above, the display quality of the conventional reflective liquid crystal display device is still insufficient.

In a liquid crystal panel, a glass substrate provided with electrodes is opposed, and a liquid crystal is held between two substrates. Members such as a polarizing plate, a retardation plate, and a reflecting plate (a backlight in the case of a transmission type) are attached to both sides of the glass panel. The thickness of the glass substrate used here is generally 0.5
mm to 1.1 mm. Further, the thickness of the plastic member such as a polarizing plate is about 0.2 to 0.5 mm, and an optical path difference is generated between the reflection plate and the liquid crystal layer. As a result, a shadow is generated on a display image. Therefore, the thickness of the substrate of the liquid crystal display device has been considered to be reduced. However, when the thickness of the glass is reduced, a problem in strength or a problem in manufacturing occurs. Therefore, as a result of using a polymer film of 0.1 to 0.4 mm as the substrate of the liquid crystal panel, parallax due to the thickness of the substrate is reduced, and a displayed image can be made clear. Also,
By using a substrate having a polarizing function or using a polarizing reflector such as a prism array, the optical path difference of the conventional polarizing plate can be reduced. Further, by adopting a polymer dispersion type liquid crystal display mode which does not require a polarizing plate, an easy-to-view display independent of a viewing angle becomes possible. Further, by using an active matrix system in which display pixels are switched by a thin film transistor (TFT) or a thin film diode (TFD), a larger amount of information can be displayed.

[0007]

EXAMPLES The present invention will be further described below with reference to examples.

Example 1 A transparent conductive film having a thickness of 120 nm was formed on a polycarbonate film having a thickness of 100 μm by a sputtering method. continue,
This transparent conductive film was processed into a stripe shape having a pitch of about 300 μm and a width of 270 μm by a usual photolithography method. After washing this film substrate, the liquid crystal alignment film AL3 made of Nippon Synthetic Rubber
046 was applied and dried, and then a rotary rubbing treatment was performed. After washing again, spherical spacers were sprayed on one of the substrates, and then bonded so that the transparent electrode patterns were orthogonal to each other. After injecting nematic liquid crystal into this cell by a vacuum injection method, a 300 μm thick
A polarizing plate having a thickness of 200 μm and a reflecting plate having a thickness of
A polarizing plate with a retardation plate of 00 μm was stuck to produce an STN type liquid crystal panel. The display area of this liquid crystal display is 96 mm x 72 mm, and the display capacity is 320 x 240
It is a dot, and the distance between the liquid crystal layer and the reflector is 400 μm. FIG. 2 shows a configuration diagram of this liquid crystal panel, and FIG. 3 shows an example in which the liquid crystal panel is mounted on an electronic book terminal. It is impossible to produce such a thin liquid crystal display panel using a conventional glass substrate. This e-book has a PC card slot,
The recorded information can be displayed on the liquid crystal display.

Example 2 After a liquid crystal cell was produced in the same manner as in Example 1, a polarizing reflection sheet (RDF manufactured by Sumitomo 3M Limited) was placed on the back side of the cell.
A phase difference plate having a thickness of 100 μm and a polarizing plate having a thickness of 200 μm were adhered to the front surface side to produce an STN (B / W mode) liquid crystal panel. In this panel, the distance between the liquid crystal layer and the reflection plate could be reduced to the substrate thickness of 100 μm because the polarizing plate on the back side was eliminated. Further, by using this polarizing reflection plate, it was possible to obtain a display that was about 40% brighter than that of Example 1. FIG. 4 shows a configuration diagram of the panel of this embodiment.

Example 3 A transparent conductive film of 100 nm was formed on a 120 μm thick polyethylene terephthalate film (Polar Solar, manufactured by Mitsui Chemicals) having a polarizing function by a sputtering method. continue,
A liquid crystal cell was manufactured in the same manner as in Example 1. STN method (B / W mode) with a reflector attached to the back side of this cell
Was manufactured. In this panel, since a polarizing plate was not required between the reflector and the liquid crystal cell, the distance between the liquid crystal layer and the reflector could be reduced to the substrate thickness of 100 μm.
FIG. 5 shows a configuration diagram of the panel of this embodiment. The transparent conductive film was processed by a normal photolithography method to form specific numbers and pictogram patterns. A film obtained by dissolving nematic liquid crystal, a monomer and a reaction initiator in this film substrate is 8 μm thick.
m, and bonded to a counter film substrate having a transparent electrode pattern corresponding to the above-mentioned substrate, and then irradiated with ultraviolet rays to produce a polymer dispersed liquid crystal (PDLC) panel.

Example 4 An SiOx film (x: 1 to 3) 50 was formed on both surfaces of a polyether sulfone film having a thickness of 100 μm by sputtering.
nm was formed. Subsequently, a transparent conductive film having a thickness of 50 nm was formed on only one surface by the same sputtering method. Subsequently, after processing this transparent conductive film by a normal photolithography method, 80 nm
The chromium film was formed by sputtering and then processed by a normal photolithography method. Subsequently, after an aluminum nitride film and an aluminum film were formed to 100 nm and 150 nm, respectively, by a sputtering method, the aluminum film was processed by a normal photolithography method to obtain an MI.
M (Metal Insulator Metal) type thin film diode (Thin Film Diode)
The devices were fabricated in an array. This film substrate and a counter film substrate having transparent electrodes in the form of stripes were bonded to each other to produce a TN liquid crystal display panel. The provision of the active element makes it possible to increase the display capacity and the display speed. The pixel pitch of the manufactured panel is about 170 μm, the display range is 136 × 102 mm, and the display capacity is 800 × 600 dots. FIG. 6 shows a configuration diagram of the liquid crystal display device of this embodiment.

Example 5 In the same manner as in Example 4, a 100 μm-thick polyethersulfone film was subjected to MIM (Metal Insulation).
Later Metal) thin-film diode (Thi
n Film Diode) elements were fabricated in an array. Nematic liquid crystal, monomer,
A solution in which a reaction initiator was dissolved was applied to a thickness of 8 μm, bonded to a counter film substrate having a transparent electrode in the form of stripes, and irradiated with ultraviolet rays to polymer-dispersed liquid crystal (P).
DLC) panel. This polymer-dispersed liquid crystal has a T
Unlike the N and STN systems, no polarizing plate is required. For this reason, the thickness of the panel can be reduced because the polarizing plate is not used, and a paper-like white with little viewing angle dependence can be expressed. The polymer-dispersed liquid crystal has a more gradual change in optical characteristics with respect to the applied voltage than the liquid crystal of the STN mode, and it is difficult to display a large capacity by simple matrix driving as in the STN mode. Thus, the display capacity can be increased.

Embodiment 6 A prism reflection sheet (BEF film manufactured by Sumitomo 3M) is provided on the back side of the MIM-driven PDLC panel in Embodiment 5.
Was placed. As a result, the brightness of the polymer-dispersed liquid crystal in the scattering state could be significantly improved, and as a result, the display contrast could be increased. FIG. 7 shows a panel configuration of this embodiment.

Example 7 Two prism reflecting sheets (BEF film manufactured by Sumitomo 3M) were provided on the back side of the MIM-driven PDLC panel in Example 6 so that the directions of the prisms were orthogonal to each other. As a result, the brightness and display contrast of the polymer-dispersed liquid crystal could be further increased.

[0015]

[Effect] 1. Claims 1 to 3 An electronic book terminal with high display quality can be realized. 2. Claim 4 In addition to the effects of Claims 1 to 3, the display capacity of the electronic book terminal can be increased. 3. Claim 5 In addition to the effects of Claims 1 to 3, an electronic book terminal with a display that is easy to read, such as paper, can be obtained. 4. Claim 6 The display of the electronic book terminal can be brightened and the display contrast can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conventional liquid crystal display device.

FIG. 2 is a diagram showing a liquid crystal display device using a polymer film for a substrate.

FIG. 3 is a diagram illustrating an example of an electronic book terminal equipped with a liquid crystal display device.

FIG. 4 is a view showing a polymer film liquid crystal display device using a reflective polarizing plate.

FIG. 5 is a view showing a liquid crystal display device using a polymer film substrate having a polarizing function.

FIG. 6 is a diagram showing a polymer film liquid crystal display device driven by an active matrix.

FIG. 7 is a diagram showing a polymer-dispersed polymer film liquid crystal display device having a prism reflection sheet on the back surface side of the substrate.

Claims (6)

[Claims] 1. An electronic book terminal having a display device for displaying digital information recorded on a built-in external recording medium, wherein the display device is a liquid crystal display device using a polymer film as a substrate. E-book terminal. 2. The electronic book terminal according to claim 1, wherein the liquid crystal display device has a polarizing reflection film disposed on the back side of the liquid crystal panel. 3. The electronic book terminal according to claim 1, wherein the liquid crystal display device is a liquid crystal display device using a polymer film having a polarizing function as a substrate. 4. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is an active matrix drive type liquid crystal display device in which a voltage applied to a liquid crystal layer by a switching element is controlled.
An electronic book terminal according to any one of the above. 5. The liquid crystal display device according to claim 1, wherein the light modulating layer made of a mixture of a liquid crystal material and a polymer material exhibits a light scattering layer state and a transparent state by an electric signal. 4. The electronic book terminal according to any one of 4. 6. The electronic book terminal according to claim 5, wherein the polymer dispersed liquid crystal display device has at least one prism array sheet disposed on the back side of the liquid crystal panel.