JPH07104280A - Filter and liquid crystal display - Google Patents

Abstract

(57) [Summary] [Construction] A filter 20 characterized in that a plastic film 22 having an antireflection film 24 formed on the surface thereof is adhered to a colored glass 21 having wavelength selectivity in transmittance, and A liquid crystal display device, wherein the filter 20 is arranged on the observer side of the liquid crystal panel 10. [Effect] Plastic film 22 on colored glass 21
The colored glass 21
Even if the glass breaks, it is possible to suppress the scattering of glass fragments. Further, reflection of light on the surface can be suppressed by the antireflection film 24. Further, the colored glass 21 allows light having a wavelength necessary for display to pass therethrough, and absorbs light in other wavelength regions to make it bright. It is possible to provide a liquid crystal display device that is easy to see without reducing the contrast even in a place.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a filter having an antiglare property and a structure of a liquid crystal display device which is improved in visibility in a bright place by using the filter.

[0002]

2. Description of the Related Art When a liquid crystal display device is used in a bright place where sunlight or the like is incident, the contrast is lowered and the image becomes difficult to see. This is because external light such as sunlight is reflected by the display device and enters the eyes together with the display image.

A technique for improving the contrast by absorbing the light reflected inside the liquid crystal display device is disclosed in Japanese Patent Laid-Open No. 3-1160.
No. 21 publication. Here, a technique of disposing colored glass on the front surface of a liquid crystal panel or a technique of using colored glass as a substrate of a liquid crystal panel is disclosed.

[0004]

However, liquid crystal display devices such as liquid crystal televisions, which are often used for portable use, are
It must be strong against drops and impacts. The above-mentioned publication discloses a liquid crystal display device in which a colored glass filter is exposed on the surface, but this configuration has a problem that glass fragments are easily scattered when the glass is broken by an impact.

The present invention solves such a problem, and provides a filter having a structure that prevents scattering of the glass even when the glass is broken due to impact on the colored glass, and using the filter Improve the contrast in
An object of the present invention is to provide a liquid crystal display device having excellent impact resistance and visibility.

[0006]

The filter of the present invention comprises:
A plastic film having a reflection reducing means formed on the surface is adhered to glass containing a coloring material.

The first liquid crystal display device of the present invention is characterized in that the filter is arranged on the observer side of a liquid crystal panel for forming an image.

In the second liquid crystal display device of the present invention, of the glass substrates constituting the liquid crystal panel for forming an image, the reflection reducing means is formed on the viewer side surface of the glass substrate on the viewer side. It is characterized in that a plastic film is adhered.

[0009]

The filter of the present invention comprises colored glass and a plastic film having reflection reducing means formed on the surface thereof, and the plastic film is adhered to the colored glass. Even if the colored glass is broken by the impact of this filter, the broken pieces are adhered to the plastic film, so that the scattered glass pieces can be prevented.

The liquid crystal display device of the present invention has this filter on the front surface.

When a liquid crystal display device such as a liquid crystal television is viewed in a bright place such as outdoors, the contrast is lowered and the screen becomes difficult to see. This is because external light such as sunlight is reflected on the surface or inside of the liquid crystal display device and overlaps the display image.

On the surface of the plastic film which is a constituent element of the filter of the present invention, an antireflection film, a light diffusing layer, or a reflection reducing means composed of a laminated structure of both is formed. The reflected light of is reduced.

On the other hand, the colored glass, which is a constituent element of the filter of the present invention, selectively absorbs light having a wavelength that does not contribute to display among the light reflected from the inside of the liquid crystal display device. In order to impart this wavelength selectivity, a plurality of rare earth elements are added to the glass.

[0014]

EXAMPLES The present invention will be described below based on examples.

(Embodiment 1) FIG. 1 is a sectional view showing a schematic structure of a filter and a liquid crystal display device in this embodiment.

Cold cathode fluorescent tube 16 serving as a light source, diffuser plate 1
7. Liquid crystal layer 11 and electrode 12 sandwiched between glass substrates 13
Liquid crystal panel 10 and phase difference compensator 1
4, a polarizing plate 15, a filter 20, and other elements.

The filter 20 has a laminated structure of an acrylic transparent resin layer 23 having a thickness of 10 μm and an antireflection film 24 composed of a dielectric multilayer film formed on the surface, and has a thickness of 0.1 mm.
The polyethylene terephthalate plastic film 22 is attached to a colored glass having a thickness of 1 mm. In this embodiment, the plastic film 22 is adhered to the colored glass 21 using an adhesive. In this case, since the adhesive forms the adhesive layer 25, it is desirable that the refractive index of the adhesive be close to that of both the plastic film and the colored glass in order to reduce light reflection at the interface of the adhesive layer.

The transparent resin layer 23 improves the hardness of the surface and reduces scratches, and at the same time, the plastic film 22.
And has a function of improving the adhesion between the antireflection film 24 and the antireflection film 24. Depending on the material and structure of the antireflection film, the transparent resin layer 23 may be omitted and the antireflection film 24 may be directly formed on the surface of the plastic film 22.

The colored glass 21 contains 6% by weight of Nd ₂ O ₃ which is a rare earth oxide, 6% by weight of Er ₂ O ₃ and ₃ % by weight of Pr ₆ O ₁₁ when the glass is melted. The transmittance spectrum 26 of this colored glass is shown in FIG. Light in the wavelength region peculiar to each rare earth ion is absorbed.

The raw materials added for imparting wavelength selectivity to the transmittance of glass are not limited to these raw materials, and other rare earth oxides, metal oxides, pigments or the like may be used.

Next, the operation of the filter 20 will be described with reference to FIG.

The light 30 emitted from the cold-cathode fluorescent tube 16 is modulated by the liquid crystal panel 10 to form a display image, and then passes through the phase difference compensating plate 14, the polarizing plate 15 and the filter 20 to be observed by the observer. When entering the eye, the observer can observe the displayed image.

On the other hand, external light 31 such as sunlight is reflected and observed at the surface of the liquid crystal display device, the interface between each optical element inside the liquid crystal display device, the interface between the electrode 12 and the glass substrate 13 inside the liquid crystal panel, and the like. Enter the eyes of the person.

Surface reflection light 32 on the surface of the liquid crystal display device can be reduced by the antireflection film 24. Although the reflectance is about 4% on the surface where the antireflection film is not formed,
The reflectance can be reduced to about 1% by the antireflection film 24 made of a two-layer dielectric film.

The antireflection film 24 is not limited to a two-layer film,
An antireflection film composed of a single layer film or a multilayer film can be used.

On the other hand, the internally reflected light 33 reflected inside the liquid crystal display device and entering the eyes of the observer can be reduced by the colored glass 21.

FIG. 2 shows an emission spectrum 27 of the cold cathode fluorescent lamp 16 together with a transmittance spectrum 26 of the colored glass 21.
Is also overlaid. The transmittance of the colored glass for light of three main wavelengths of the cold cathode fluorescent tube is high, while the transmittance of light of wavelengths other than the emission wavelength of the cold cathode fluorescent tube is low. Especially 510-540 nm and 560-610
Light with a wavelength of nm is selectively and largely absorbed. These wavelength regions are wavelength regions in which the human eye has high relative luminous efficiency, and absorption of light in these wavelength regions brings about an effect of reducing glare.

The filter 20 of the present invention reduces the reflection on the surface and absorbs little light from the cold cathode fluorescent tubes involved in display, while it is unnecessary for the external light to the display and causes no glare. The light in the wavelength range to be introduced passes through the colored glass 21 twice before being reflected inside the liquid crystal display device and entering the eyes of the observer, and is greatly attenuated.

Therefore, the brightness of the displayed image is less attenuated, while unnecessary reflected light is largely attenuated by the antireflection film 24 and the colored glass 21, so that the image with little contrast reduction can be seen even in a bright place such as outdoors. It is possible to configure a liquid crystal display device capable of

Further, since the plastic film 22 is adhered to the colored glass 21, even if the colored glass is broken by dropping or hitting the liquid crystal display device, scattering of glass fragments can be suppressed.

(Second Embodiment) A second embodiment of the filter according to the present invention will be described with reference to FIG.

A light diffusion layer 28 is formed on the surface of a polyethylene terephthalate plastic film 22 having a thickness of 0.1 mm.
Are formed. The light diffusion layer 28 is formed by processing the surface of the resin applied to the surface of the plastic film 22 into a satin finish. This light diffusion layer 28 can reduce gloss reflection on the surface and make the background reflected on the surface of the liquid crystal display device inconspicuous.

This plastic film 22 is adhered to the colored glass 21 similar to that of the first embodiment.

Even if the filter of this embodiment is used instead of the filter in the liquid crystal display device described in the first embodiment, a liquid crystal display device which is easy to see even in a bright place and has little influence on impact can be constructed.

(Embodiment 3) A third embodiment of the filter according to the present invention will be described with reference to FIG.

A transparent resin layer 40 having silica fine particles 41 dispersed therein is formed on a polyethylene terephthalate plastic film 22 having a thickness of 0.1 mm, and an antireflection film 24 is formed on the surface thereof. With this configuration,
It is possible to reduce the reflection on the surface and the reflection of the background.

This plastic film 22 is adhered to the colored glass 21 similar to that of the first embodiment.

Even when the filter of this embodiment is used in place of the filter in the liquid crystal display device described in Embodiment 1, it is possible to construct a liquid crystal display device which is easy to see even in a bright place and has little influence on impact.

(Embodiment 4) The liquid crystal display device according to the present embodiment is a reflective liquid crystal display device, and is a liquid crystal display device in which display is performed by light incident from the outside of the liquid crystal display device. The filter described in Example 1 is used as the filter.

FIG. 5 shows a sectional view of the reflective liquid crystal display device of this embodiment. External light 31 is filter 20, polarizing plate 1
5, the phase difference compensating plate 14, the liquid crystal panel 10 and the polarizing plate 15 are transmitted, the light is reflected by the reflecting plate 50, and again passes through the liquid crystal panel 10 to enter the eyes of the observer as display light 51, and an image is recognized.

As can be seen from the transmittance spectrum 26 of the colored glass 21 shown in FIG. 2, 430 nm and 550 n
Light with wavelengths near m and 610 nm, that is, blue, green, and red, is attenuated little, and light with wavelengths required for color reproduction of a display is little attenuated in both black and white images and color images.

On the other hand, light in the wavelength region not required for color reproduction of the display is greatly attenuated by absorption by rare earth ions. Therefore, it is possible to configure a reflective liquid crystal display device that is less affected by impact and has improved contrast and excellent visibility.

(Embodiment 5) The liquid crystal display device of this embodiment is a reflection type liquid crystal display device, but unlike the reflection type liquid crystal display device of embodiment 4, it utilizes the scattering of light at the interface between the liquid crystal and the polymer. It is a reflection type liquid crystal display device that performs display.

FIG. 6 is a sectional view showing the structure of the reflection type liquid crystal display device in this embodiment.

A liquid crystal layer 61 sandwiched between the glass substrates 13,
The liquid crystal panel 60 is composed of the electrode 12, the reflective layer 62 also serving as the electrode, and the like. On the viewer side of the liquid crystal panel 60, the filter 20 similar to that of the first embodiment is arranged.

(Embodiment 6) FIG. 7 is a sectional view of the reflection type liquid crystal display device according to this embodiment. Of the two glass substrates constituting the liquid crystal panel 70, the glass substrate on the observer side is colored glass. Doubles as The liquid crystal panel 70 performs display by utilizing light scattering at the interface between the liquid crystal and the polymer.

The colored glass substrate 71 is glass containing a rare earth oxide as in Example 1, and has wavelength selectivity in transmittance. Elements such as electrodes 12 for driving liquid crystals are formed on this substrate. Depending on the composition of the glass substrate, it is necessary to form a protective film on the surface of the glass substrate on the liquid crystal side to prevent the elution of impurities.

A transparent resin layer 23 and an antireflection film 24 are provided on the surface.
The laminated plastic film 22 is adhered to the colored glass substrate 71.

By using colored glass for the glass substrate of the liquid crystal panel as in the present embodiment, it is not necessary to newly provide colored glass, so that the liquid crystal display device can be made thin.

[0050]

The filter of the present invention comprises a plastic film on which a reflection reducing means such as an antireflection film is formed.
It is adhered to colored glass having wavelength selectivity in transmittance, and has the effect of suppressing the scattering of glass fragments even if the glass breaks due to impact.

Further, the liquid crystal display device of the present invention equipped with the above filter has an effect that it is easy to see even in a bright place because unnecessary unnecessary reflected light is small, and scattering of glass fragments is suppressed even if the glass is broken by an impact. Therefore, it is possible to provide a liquid crystal display device which can be used in a portable manner without anxiety and is particularly excellent in visibility outdoors.

Further, in another liquid crystal display device of the present invention in which a glass substrate constituting a liquid crystal panel is colored and a plastic film having antireflection means is adhered to the surface thereof, it is not necessary to newly provide colored glass. Therefore, there is an effect that it is possible to reduce the thickness of the liquid crystal display device which is excellent in visibility and less affected by impact.

[Brief description of drawings]

FIG. 1 shows a first filter and liquid crystal display device according to the present invention.
FIG.

FIG. 2 is a diagram showing a transmittance spectrum of a colored glass which is a constituent element of the filter of the present invention and an emission spectrum of a cold cathode fluorescent tube which is a constituent element of a liquid crystal display device.

FIG. 3 is a sectional view showing a second embodiment of the filter of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the filter of the present invention.

FIG. 5 is a sectional view showing a second embodiment of the liquid crystal display device of the present invention.

FIG. 6 is a sectional view showing a third embodiment of the liquid crystal display device of the present invention.

FIG. 7 is a sectional view showing a fourth embodiment of the liquid crystal display device of the present invention.

[Explanation of symbols]

 10, 60, 70 Liquid crystal panel 11, 61 Liquid crystal layer 12 Electrode 13 Glass substrate 14 Phase difference compensating plate 15 Polarizing plate 16 Cold cathode fluorescent tube 17 Diffusing plate 20 Filter 21 Colored glass 22 Plastic film 23, 40 Transparent resin layer 24 Antireflection Film 25 Adhesive layer 26 Transmittance spectrum of colored glass 27 Emission spectrum of cold cathode fluorescent tube 28 Light diffusion layer 30 Light from cold cathode fluorescent tube 31 External light 32 Surface reflected light 33 Internal reflected light 41 Fine particles 50 Reflector 51 Display light 62 reflective layer 71 colored glass substrate

Claims (3)

[Claims] 1. A filter characterized in that a plastic film having a reflection reducing means formed on the surface thereof is adhered to glass containing a coloring material. 2. A liquid crystal display device, wherein the filter according to claim 1 is arranged on the observer side of a liquid crystal panel for forming an image. 3. A glass film constituting a liquid crystal panel for forming an image, wherein a plastic film having antireflection means is adhered to the surface of the glass substrate on the viewer side on the viewer side. Characteristic liquid crystal display device.