JP2002250916A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device in which picture display can be efficiently performed by using both of the external light and an internal light source. SOLUTION: In the liquid crystal display device having a transparent substrate and at least a diffusing layer, a reflecting layer or the like formed on the transparent substrate, a back light is disposed in the lower side of the transparent substrate and further microlenses are disposed above the back light and below the diffusing layer in the position between non-reflective layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device capable of efficiently displaying a screen by using both external light and an internal light source.

[0002]

2. Description of the Related Art For example, a liquid crystal display device generally includes a pair of opposing electrode substrates on which a polarizing film and a transparent electrode are respectively disposed, a liquid crystal substance sealed between these electrode substrates, and a color on one of the electrode substrates. The main part is constituted by the filter layer. These liquid crystal display devices are used in portable display devices such as mobile devices, which are characterized by low power consumption.

[0003] As a liquid crystal display device used for these,
2. Description of the Related Art A transmissive liquid crystal display device in which a backlight is disposed on the back side of an electrode substrate on the back side and a light source irradiated from a built-in light source is incident on the back side substrate to obtain a display screen has been widely used.

However, the transmissive liquid crystal display device incorporating the above light source has a drawback that it is difficult to use it for a long time because the power consumption by the light source is large, and it cannot make full use of its characteristics as a portable device.

Therefore, a reflection type liquid crystal display device utilizing external light has been developed. In a reflection type liquid crystal display device, external light is made to enter into the device (from a non-pixel portion) from a substrate on the viewing side, and is reflected by a metallic (Ag / Pd, Al, etc.) reflective film provided on the back substrate side. The screen display is performed using the reflected light. This reflective film has a light scattering property to scatter reflected light by providing irregularities on the surface.

[0006]

However, in the above-mentioned conventional reflection type liquid crystal display device, although a part of the light incident on the non-pixel portion is used, the reflection film improves the viewing angle as the display device. Therefore, there is a problem that image display cannot be appropriately performed when external light is weak or absent.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display device which can enhance the use efficiency of a backlight and can be used as a reflection type.

[0008]

That is, the present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 comprises a transparent substrate, a diffusion layer and a reflection layer provided on the transparent substrate. In a liquid crystal display device including a color filter layer and the like, a backlight is provided below the transparent substrate,
Further, a micro lens is provided above the backlight and below the diffusion layer so as to be located between the non-reflection layers.

[0009] More specifically, as described in claim 2, the microlens is arranged in such a manner that light is condensed on a transmission portion between non-reflection layers.

Further, as described in claim 3, the microlenses are arranged so as to be in contact with each other according to the configuration of the color filter.

[0011]

The present invention adopts a method of displaying an image by using external light in the daytime or a place where a light source is present, and adopts a method of using a backlight which is an internal light source in the case of darkness.

Therefore, when external light is used, there is an advantage that an image can be displayed efficiently by making the external light incident from the outer transparent substrate and scattering the light by the internal reflection layer. Further, when a backlight is used, there is an advantage that an image can be displayed efficiently by arranging the light from the backlight with a microlens so as to be condensed on a transmissive portion between non-reflective layers.

Further, the microlenses can be used in all liquid crystal display devices by arranging the microlenses so as to be in contact with each other in accordance with the configuration of the color filters individually arranged.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, one embodiment of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing one embodiment of the liquid crystal display device of the present invention, and FIG. 2 is a schematic cross-sectional view in which the microlens portion of FIG. 1 is enlarged.

The liquid crystal display device of the present invention is, specifically, a transflective liquid crystal provided with a backlight (not shown) mechanism as a transmissive liquid crystal display device and a reflective film as a reflective liquid crystal display device. The display device 1.

In this apparatus 1, a micro lens 3 is provided on a transparent substrate 2, a diffusion layer 4 is provided on the micro lens 3 via a flattening layer, and an Ag / p
d, a metallic reflective film 5 made of Al or the like, an ITO film 6 provided on the reflective film 5, a color filter (red (R),
The pixel unit 7 includes green (G) and blue (B)), an undercoat layer 8 provided on the pixel unit 7, and a transparent substrate 9.

The surface of the reflective film 5 is provided with irregularities and has a light scattering property for scattering reflected light.

The microlenses 3 are arranged between the reflective films 5 (between the non-reflective portions, hereinafter referred to as a transmitting portion 5a) so as to continuously contact vertically and horizontally according to the structure of the color filter. It is provided so as to condense light from the provided backlight 10 to the transmission part 5a. As a result, an image can be displayed using a small amount of light or a small amount of light without waste, thereby enabling use with low power consumption.

Next, an example of use of the transflective liquid crystal display device 1 will be described. FIG. 3 is a schematic test diagram showing an external light incident and an image display state by a backlight.

When there is external light in the daytime or the like, the external light passes through the transparent substrate 9 and the pixel section 7 and is reflected while being scattered by the reflection film 5, thereby displaying an image.

In the case of nighttime (dark night), light is transmitted through the microlens 3 using the backlight 10 and the transmitting portion 5.
After being condensed on a, the light is incident on the pixel unit 6 and an image can be displayed without waste. Therefore, unlike a conventional transmissive liquid crystal display device, the structure does not always use a backlight, so that it consumes less power and can be used for a long time. In addition, it is possible to make up for the disadvantage that it cannot be used in a place without light.

The microlens 3 used is preferably one having a high light transmittance and a high refractive index. As the material, for example, a polycarbonate resin, a polyester resin, an acrylic ethoxy resin and the like are applicable.

Further, the material of the flat layer formed on the microlens 3 is preferably a material having a low refractive index, for example, an organic silicate having a refractive index of about 1.46 or fluorine having a refractive index of about 1.40. A system resin or the like is appropriate.

The material of the reflection layer includes aluminum, silver and the like. In other words, silver has a higher reflectance than aluminum at a light wavelength in the visible region, and can provide a bright display screen. However, silver is apt to cause migration, and the durability is significantly reduced in the presence of moisture, alkali metal, and the like. In order to stabilize silver, an alloy obtained by adding a metal such as gold or copper to silver is preferable.

[0025]

The liquid crystal display device according to the present invention has the characteristics of a reflection type liquid crystal display device and a transmission type liquid crystal display device. However, when there is no external light, an image can always be displayed by the internal light source, so that there is a special effect that the utilization efficiency is good.

Further, when an image is displayed by an internal light source, the use of a microlens has the effect that an image can be displayed by condensing even a small amount of light.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a schematic cross-sectional view in which a microlens portion in FIG. 1 is enlarged.

FIG. 3 is a schematic diagram illustrating an image display state by a backlight when external light is incident.

[Explanation of symbols]

 1: Liquid crystal display

Claims (3)

[Claims] 1. A liquid crystal display device having at least a transparent substrate and a diffusion layer and a reflective layer provided on the transparent substrate, wherein a backlight is provided below the transparent substrate,
A liquid crystal display device, wherein a microlens is arranged above the backlight and below the diffusion layer so as to be located between the non-reflection layers. 2. The liquid crystal display device according to claim 1, wherein the microlenses are arranged so that light is condensed on a transmission portion between the non-reflection layers. 3. The liquid crystal display device according to claim 1, wherein the microlenses are arranged so as to be in contact with each other according to the configuration of the color filter.