JPH10333145A - Liquid crystal display device equipped with lighting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting mechanism on a liquid crystal display device(LCD), to unnecessitate a light source and to reduce the power consumption. SOLUTION: A reflection layer 16 is installed on the outside of a substrate 10 where a TFT(thin-film transistor) 14 is installed and a light guide layer 17 is installed between the reflection layer 16 and the substrate 10. The light introduced to the light guide layer 17 is reflected on the reflection layer 16, also, changed to linearly polarized light by a polarizing element 15 and the light is made incident to a liquid crystal 30. Since the liquid crystal 30 is controlled to desired orientation, a desired modulation is applied on the linearly polarized light made incident on the crystal 30 and a transmissivity is controlled by a polarizing plate 24 at every pixel to recognize the light as a displayed image.

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 (LCD) for performing display utilizing the electro-optical anisotropy of liquid crystal.
In particular, the present invention relates to a liquid crystal display device with a lighting mechanism, which has a lighting mechanism to reduce power consumption of a backlight.

[0002]

2. Description of the Related Art An LCD is constructed by sealing liquid crystal between electrode substrates having transparent electrodes formed on a transparent substrate. Since the liquid crystal has electro-optical anisotropy, by applying a desired voltage between the electrodes to form an electric field in the liquid crystal, the liquid crystal exhibits optical characteristics according to the electric field intensity. Therefore, by controlling the voltage for each pixel, a display image is created as an aggregate of pixels exhibiting a desired luminance. As described above, in the LCD, a display image is created by voltage control, and the LCD is small-sized,
It has advantages such as thinness and low power consumption, and has been put to practical use in fields such as OA equipment and AV equipment.

FIG. 5 shows a configuration diagram of an LCD. (1) is L
CD, (2) is a light guide, and (3) is a light source. The light guide section (2) includes a light guide layer (2a) made of an acrylic resin or the like, and a light reflection layer (2b) inside the outer surface thereof. As the light source (3), a fluorescent lamp or the like is used. Also, the light guide (2) is often
The back surface has been subjected to light reflection processing, and the exit surface has been subjected to light diffusion processing. Normally, the light guide section (2) and the light source (3) are integrated as a backlight unit to form a surface light source.

[0004]

Since a display screen created by an LCD cannot be observed as an image by itself, as shown in FIG. 5, it is used integrally with a backlight to transmit transmitted light. It is actually visualized in the form of an intensity distribution. Therefore, the power used for the backlight is large, and the advantage of the low power consumption of the LCD itself has not been fully utilized.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and a liquid crystal is provided between a pair of electrode substrates each having a liquid crystal driving electrode formed on first and second transparent substrates. Is sealed, a plurality of pixels comprising the electrode and liquid crystal are formed, while applying a predetermined voltage to the electrode, by irradiating light to the liquid crystal, in a liquid crystal display device with a lighting mechanism for creating a display image, An inward first light reflection surface is provided outside the first electrode substrate, and the first electrode substrate and / or the second electrode substrate have a pixel region other than the pixel region on the side facing the second electrode substrate. A liquid crystal display device with a lighting mechanism, wherein a second light reflecting surface facing the first light reflecting surface is provided, and external light is applied to the liquid crystal.

Thus, the first transparent substrate itself serves as a light guide layer to introduce light from the outside, and this light is further reflected by the first reflection surface and irradiated to the liquid crystal. Further, the light applied to the non-pixel area is reflected by the second reflection surface, returned to the first reflection surface, and applied again to the pixel area of the liquid crystal. A bright display screen is obtained.

In particular, a light guide layer having high photoconductivity is provided between the first electrode substrate and the first reflection surface. As a result, the amount of guided light is increased, and a bright display screen is obtained. In particular, the configuration is such that a polarizing element is provided on the surface of the first reflection surface. As a result, the light introduced from the outside is transformed into linearly polarized light and applied to the liquid crystal, so that it is rotated by the liquid crystal and controlled to a predetermined transmittance.

In particular, the first light reflecting surface is provided with a concave surface corresponding to each pixel, and external light is condensed on a pixel region and irradiated to the liquid crystal. As a result, the introduced light is efficiently radiated to the pixel region, so that the light use efficiency is further increased and a brighter display screen is obtained. In particular, the configuration is such that a light-shielding film is provided in a region other than the pixel region of the second transparent substrate.

As a result, reflection of the non-pixel area on the observation surface is prevented, so that the display quality is improved.

[0010]

FIG. 1 is a sectional view of an LCD with a daylighting mechanism according to a first embodiment of the present invention. (10)
Is a first transparent substrate made of glass or the like, (11) is a second light reflection layer at least downward in the figure such as Al or a mirror,
(12) is an insulating layer, and (13) is ITO (Indiumu Tin Ox).
ide) and other pixel electrodes for driving liquid crystal made of a transparent conductive film,
(14) is a switching element connected to the pixel electrode (13), for example, a TFT (Thin Film Transistor), (1)
5) is a first polarizing element such as a polarizing plate or a beam splitter, and (16) is a first light reflection layer such as Al and a mirror at least upward in the drawing. Further, (20) facing the first transparent substrate (10) is a second transparent substrate such as glass, (21) is a light shielding film, (22) is a second light reflection layer such as Al or a mirror, (23) is a common electrode for driving a liquid crystal made of ITO or the like. These substrates (10) and (20)
A liquid crystal (30) is provided between them. Further, a second polarizing plate (24) is provided above the transparent substrate (20).

The common electrode (23) and the liquid crystal (30) are partitioned by the pixel electrode (13), and constitute a pixel composed of a capacitor using the liquid crystal as a dielectric layer. A predetermined signal voltage is supplied to the common electrode (23), and a TFT is applied to the pixel electrode (13).
A data signal voltage for driving the liquid crystal is supplied via (14). The orientation of the liquid crystal changes depending on the strength of the electric field formed by the voltage applied between the common electrode (23) and the pixel electrode (13).

In the present invention, external light such as sunlight or indoor lighting is introduced from the side of the first transparent substrate (10),
Is reflected by the light reflection layer (16). This reflected light is the first
The liquid crystal (30) is transformed into linearly polarized light by the polarizing element (15). The first transparent substrate (10) is 1 mm to 5 mm thicker than the conventional one so that daylighting can be performed.
A degree is desirable.

The liquid crystal (30) has its orientation controlled for each pixel, rotates the incident linearly polarized light, and this is narrowed down by the second polarizing plate (24) at the time of emission to adjust the liquid crystal to a desired transmittance. Is done. Thus, in the LCD using the TFT, the transmittance is controlled for each pixel by the voltage control.
Low power consumption. However, since it is necessary to irradiate light to actually view the screen of the LCD, the power consumption of the light source is large, and the advantage of low power consumption of the LCD itself has been lost as a whole.

For this reason, according to the present invention, the light source is unnecessary by illuminating the liquid crystal with external light.
Reduced power consumption. In addition, on the first transparent substrate (10) and / or the second transparent substrate (20), in a non-pixel region, a second light reflection layer (11) facing the first light reflection layer is provided.
Or / and (22), the first light reflecting layer (16)
Out of the irradiated light, the light in the non-pixel region
By returning the light to the light reflection layer (16) and irradiating the pixel region again, the light use efficiency is increased and a bright display screen is obtained.

FIG. 2 is a sectional view of an LCD with a lighting mechanism according to a second embodiment of the present invention. In the present embodiment, a light guide layer (1) made of a high light guide material such as an acrylic resin is provided between the first transparent substrate (10) and the first reflective layer (16).
7) is provided. External light, such as sunlight and indoor lighting, is introduced from the light guide layer (17), is transmitted uniformly in the LCD panel, is reflected by the first light reflection layer, and irradiates the liquid crystal (30). Is done. This reflected light is changed to linearly polarized light by the first polarizing element, enters the liquid crystal (30),
The light is modulated by the liquid crystal (30) and emitted from the second polarizing plate (24) with the transmittance controlled for each pixel.

In the present embodiment, the amount of light collected is increased by the light guide layer (17), so that a brighter display screen can be obtained. FIG. 3 is a cross-sectional view of an LCD with a lighting mechanism according to a third embodiment of the present invention. In the present embodiment, the reflection surface of the first light reflection layer (16) is processed into a concave shape corresponding to each pixel. Therefore, the first transparent substrate (10)
The external light introduced into the pixel is reflected by these concave surfaces (18) and is collected on the pixel area. For this reason, the efficiency of use of light from daylighting to illumination is enhanced, and a brighter display screen is obtained.

FIG. 4 is a sectional view of an LCD with a lighting mechanism according to a fourth embodiment of the present invention. In the present embodiment, a light guide layer (17) made of a light guide material such as an acrylic resin is provided between a first light reflection layer (16) having a concave surface processing and a first transparent substrate (10). Have been. For this reason,
A large amount of external light such as sunlight and indoor lighting is introduced into the light guide layer (17), reflected by the concave surface (18) formed in the first light reflection layer (16), and collected into pixels. . For this reason, since both the amount of collected light and the efficiency of use of light from lighting to illumination are improved, a brighter display screen can be obtained.

[0018]

As is apparent from the above description, by providing the liquid crystal display device with the lighting mechanism, even if there is no light source,
A sufficiently bright display screen was obtained, and low power consumption was realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an LCD with a daylighting mechanism according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an LCD with a lighting mechanism according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an LCD with a lighting mechanism according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of an LCD with a daylighting mechanism according to a fourth embodiment of the present invention.

FIG. 5 is a side view of a conventional LCD.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LCD 2 Light guide part 3 Light source 10,20 Transparent substrate 11,16,22 Light reflection layer 13 Pixel electrode 14 TFT 15,24 Polarizer 17 Light guide layer 18 Concave surface 21 Light shielding film 23 Common electrode

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Makoto Shimizu 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Tokuo Koma 2-chome, Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Ryuji Nishikawa 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (5)

[Claims] A liquid crystal is sealed between a pair of electrode substrates each having a liquid crystal driving electrode formed on a first and a second transparent substrate, and a plurality of pixels including the electrodes and the liquid crystal are formed.
A liquid crystal display device with a lighting mechanism for creating a display image by applying a predetermined voltage to the electrode and irradiating the liquid crystal with light, wherein an inward first light is provided outside the first electrode substrate. A reflection surface is provided, and a second light reflection surface facing the first light reflection surface is provided in a region other than the pixel region on the side facing the first electrode substrate and / or the second electrode substrate. A liquid crystal display device with a lighting mechanism, characterized in that external light is applied to the liquid crystal. 2. A liquid crystal display with a lighting mechanism according to claim 1, wherein a light guide layer having high photoconductivity is provided between said first electrode substrate and said first reflection surface. apparatus. 3. The liquid crystal display device with a daylighting mechanism according to claim 1, wherein a polarizing element is provided on a surface of said first reflection surface. 4. The liquid crystal display according to claim 1, wherein the first light reflection surface is provided with a concave surface corresponding to each pixel, and external light is condensed on a pixel region and irradiated to a liquid crystal. Liquid crystal display with lighting mechanism. 5. A light-shielding film is provided in a region other than the pixel region of the second transparent substrate.
The liquid crystal display device with the lighting mechanism according to the above.