JPH1152345A - Reflection type liquid crystal panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody the reduction in the thickness of a reflection type liquid crystal panel by incorporating light storable phosphors into protective films themselves holding polarizing films of a reflection type liquid crystal panel. SOLUTION: This liquid crystal panel comprises liquid crystal substrates A, a pair of upper and lower polarizing plates B, C which hold the liquid crystal substrates A from both sides and a reflection plate D which is disposed on the rear surface of the lower polarizing plate C. In addition, the lower polarizing plate C is so constituted as to consist of a three-layered structure composed of the polarizing film 16 and the protective films 17a, 17b arranged on both sides thereof. In such a case, the light storable phosphors are incorporated into at least the protective film of one side of the protective films 17a, 17b constituting the lower polarizing plate C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal panel comprising a liquid crystal substrate, a pair of polarizing plates sandwiching the liquid crystal substrate from both sides, and a reflecting plate disposed on the lower surface of the lower polarizing plate. It is about.

[0002]

2. Description of the Related Art A liquid crystal panel generally has a structure in which a liquid crystal substrate A is sandwiched between an upper polarizing plate B and a lower polarizing plate C from above and below as shown in FIG. In particular, in a reflection type liquid crystal panel having no backlight, a reflection plate D made of a reflection film or the like is provided on the lower surface of the lower polarizing plate C,
A method of illuminating a liquid crystal panel surface by reflecting incident light is often used, but in indoors where external light does not sufficiently hit due to light loss caused by passing through a polarizing plate, reflected light is weak and sufficient. Brightness may not be obtained. Accordingly, the applicant of the present application has proposed a method of increasing the luminous efficiency by utilizing not only reflected light but also accumulated light,
A reflective liquid crystal panel having both a reflective film and a luminous fluorescent film has already been proposed in Japanese Patent Application No. 7-346675.

As shown in FIG. 3, this reflection type liquid crystal panel has a phosphorescent phosphor film 3 between a lower deflecting plate C and a reflecting plate D.
The phosphorescent film 3 is formed to a predetermined thickness by printing on one of the protective films 2a and 2b sandwiching the polarizing film 1 from both sides. In addition to printing, as shown in FIG. 4, the phosphorescent phosphor film 3 and the adhesive 6 are integrally provided on the reflection plate D, and the release sheet 7 is peeled off and attached to the lower surface of the lower polarizing plate C. There is also a way to attach.

[0004]

However, in the above case, since the amount of light stored in the luminous phosphor film 3 depends on its thickness, it takes several times to form the luminous phosphor film 3 to a predetermined thickness. However, there is a problem that printing must be repeated, which increases the number of printing steps and manufacturing costs. When the thickness of the phosphorescent phosphor film 3 is increased to increase the amount of accumulated light,
As a result, the entire liquid crystal panel becomes thicker, which hinders the thinning.

Accordingly, the present invention provides a reflection type liquid crystal panel which can omit a printing step and realize a thin liquid crystal panel by incorporating a phosphorescent phosphor into a protective film itself sandwiching a polarizing film. .

[0006]

In order to solve the above problems, a reflection type liquid crystal panel according to the present invention comprises a liquid crystal substrate, a pair of upper and lower polarizing plates sandwiching the liquid crystal substrate from both sides, and a lower polarizing plate. A liquid crystal panel having a three-layer structure of a polarizing plate and a protective film disposed on both sides of the polarizing film. Of these, at least one of the protective films contains a phosphorescent phosphor.

[0007] The reflection type liquid crystal panel according to the present invention comprises:
It is characterized in that a phosphorescent phosphor is blended in an amount of 5 to 10% by weight in a protective film made of triacetyl cellulose.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a reflection type liquid crystal panel according to the present invention.
FIG. 1 shows a cross-sectional configuration of a reflective liquid crystal panel according to the present invention, in which a liquid crystal substrate A, an upper polarizing plate B and a lower polarizing plate C sandwiching both the upper and lower sides thereof, and a lower polarizing plate C are formed. And a reflection plate D disposed on the lower surface side.

The liquid crystal substrate A has a pair of transparent glass substrates 8 and 10 arranged vertically, and the transparent glass substrates 8 and 10 are fixed by a spacer 13 formed of fiber glass, glass powder or the like. Spacing, for example 5-15μ
They are arranged in parallel with an interval of m. A segment electrode 9 and a common electrode 11 are formed on the opposing inner surfaces of the transparent glass substrates 8 and 10, respectively. The segment electrodes 9 and the common electrodes 11 are used to arrange liquid crystal molecules to be sealed thereon in a desired fixed direction. Each of the alignment films 12 is formed.
The transparent glass substrate 8 of the liquid crystal substrate A thus configured,
A liquid crystal substance 14 is injected between the gaps 10, and the periphery of the transparent glass substrates 8, 10 is sealed with a sealing member made of frit glass, an organic adhesive or the like.

The upper polarizing plate B is disposed on the upper surface side of the transparent glass substrate 8 and converts the incident natural light into linearly polarized light and emits the light. The pair of upper and lower polarizing films 16 cover the polarizing film 16 from above and below. Transparent protective films 15a, 15b
And is bonded to the transparent glass substrate 8 via an adhesive 19. On the other hand, the lower polarizing plate C disposed on the lower surface side of the transparent glass substrate 10 is composed of the polarizing film 16 and the transparent protective films 17a and 17b covering the upper and lower surfaces thereof, like the upper polarizing plate B. However, the lower protective film 17b contains a phosphorescent phosphor.

The protective film 17b containing the luminous phosphor is mainly made of triacetylcellulose having excellent heat resistance and hot water resistance. It is formed in. In particular, the protective film 17 is prepared by mixing and dispersing a phosphorescent phosphor in a triacetyl cellulose resin in an amount of 5 to 10% by weight.
In the case of b, the balance between the light emission luminance and the film strength is maintained, and the light accumulated in the luminous phosphor is efficiently emitted to illuminate the liquid crystal panel surface brighter and pass through the polarizing film 16. Can be sufficiently compensated for, and strong reflected light can be obtained even indoors where external light is not sufficiently applied.
If the amount of the phosphorescent phosphor is more than this, the triacetyl cellulose film may be fragile,
On the other hand, if it is less than this, the emission luminance and the afterglow time are undesirably reduced.

As the phosphorescent phosphor, a long-persistence phosphor is preferable, for example, aluminum strontium oxide,
A phosphor obtained by firing a fluorescent substrate such as calcium aluminum oxide or an activator of europium is most suitable.
Triacetyl cellulose is also used for the protective films 15a, 15b, and 17a at other portions. However, as a protective film using any other material, an acrylic resin that improves moisture resistance and transparency is used as a raw material. Alternatively, an acetylcellulose containing an ultraviolet (UV) absorber as a raw material can be used. Further, the polarizing film 16 used for the upper polarizing plate B and the lower polarizing plate C is manufactured by a known method, is stretched while heating a thin film of polyvinyl alcohol, and is coated with an H ink containing a large amount of iodine. When brought into contact with a so-called solution, the polyvinyl alcohol film absorbs iodine in the H ink, and the above-mentioned polarizing film 16 having a polarizing ability can be obtained.

A reflecting plate D is provided on the lower surface of the phosphorescent phosphor-containing protective film 17b having the above-described structure. The reflection plate D is constituted by a reflection film 18 formed by printing or applying a white paint ink containing barium titanate on the entire lower surface of the protective film 17b containing the luminous phosphor. The material of the reflection film 18 is preferably a material having a higher reflection effect, and is not particularly limited to the material shown in the present embodiment. However, except for the barium titanate, SiO, SiO2, Zr2O
3, MgF2 and the like are also suitable. Further, a metal film having a high reflectance may be formed by vapor deposition or sputtering, or a metal foil film having a high reflectance may be formed by bonding.

In the above embodiment, the case where the phosphorescent substance is contained in the protective film 17b disposed on the lower surface side of the lower polarizing plate C has been described, but the protective film 17a on the upper surface side of the lower polarizing plate C has been described. It is also possible to include a phosphorescent phosphor in the phosphor. Further, those contained in both protective films may be used.

[0015]

As described above, according to the reflection type liquid crystal panel of the present invention, since the phosphorescent substance is contained in the protective film which is a component of the polarizing plate, the entire liquid crystal panel can be made thinner. can do.

Further, triacetyl cellulose is used as a raw material for the protective film, and the compounding ratio of the phosphorescent phosphor is 5%.
Since the content is set to 10 to 10% by weight, the strength as a polarizing plate can be secured, and the light storage and light emission effects can be maintained.

Further, since the luminous phosphor is contained in the protective film which is a component of the polarizing plate, it is not necessary to finish the luminous phosphor film to a predetermined thickness by a conventional printing step or coating step. In addition, the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a reflection type liquid crystal panel according to the present invention.

FIG. 2 is a basic configuration diagram of a liquid crystal panel.

FIG. 3 is a cross-sectional view of a conventional reflector having a reflection film and a light storage film.

FIG. 4 is a cross-sectional view of a sheet-like reflecting plate to be attached to a conventional polarizing plate.

[Explanation of symbols]

 Reference Signs List A Liquid crystal substrate B Upper polarizing plate C Lower polarizing plate D Reflector 15a Protective film 15b Protective film 16 Polarizing film 17a Protective film 17b Protective film containing phosphorescent phosphor 18 Reflective film

Claims (2)

[Claims] 1. A liquid crystal substrate, comprising a pair of upper and lower polarizing plates sandwiching the liquid crystal substrate from both sides, and a reflecting plate disposed on a lower surface of a lower polarizing plate, wherein the polarizing plate includes a polarizing film and a polarizing film. In a liquid crystal panel having a three-layer structure with protective films disposed on both sides, of the protective films constituting the lower polarizing plate, at least one of the protective films contains a phosphorescent phosphor. Type liquid crystal panel. 2. The reflection type liquid crystal panel according to claim 1, wherein said protective film is made of triacetyl cellulose as a raw material and contains 5 to 10% by weight of a luminous phosphor.