The present invention relates to liquid crystal display (LCD) panels and liquid crystal display devices using LCD panels, and more particularly to a reflection/transmission type LCD device capable of providing a display both in a reflection mode and a transmission mode.
Among LCD products, there have been the following three types of LCD devices commercially available: a reflection type LCD device utilizing ambient light, a transmission type LCD device utilizing backlight, and a semi-transmission type LCD device equipped with a half mirror and a backlight. With a reflection type LCD device, a display becomes less visible in a poorly lit environment. In contrast, a display of a transmission type LCD device appears hazy in strong ambient light (e.g., outdoor sunlight). Thus researchers sought to provide an LCD device capable of functioning in both modes so as to yield a satisfactory display in any environment. In due course, a reflection/transmission type LCD device was developed.
Part of an LCD panel of a typical reflection/transmission type LCD device is shown in
The second electrode layer 16 includes a plurality of reflection portions 161 and a plurality of transmission portions 162 which are alternately arranged. The reflection portions 161 are made of highly reflective material, and the transmission portions 162 are made of transparent material.
In use, when the ambient light is strong enough, the liquid crystal display panel 10 is used in a reflection mode. Ambient light beams above the liquid crystal display panel 10 pass through the top polarizer 1, the color filter 5, and the liquid crystal layer 8 and irradiate the reflection portions 161. The ambient light beams are reflected by the reflection portions 161, and pass back through the color filter 5 and the top substrate 4 to display images.
When the ambient light is poor, the LCD panel 10 is used in a transmission mode. Light beams emitted by a backlight (not shown) below the liquid crystal display panel 10 pass through the transmission portions 162, the liquid crystal layer 8, the color filter 5, and the top substrate 4 to display images.
However, light beams pass through the color filter 5 twice in the reflection mode, but only once in the transmission mode. This causes the color saturation of displayed images to be different in the two modes. Moreover, when light beams pass through the color filter 5 twice in the reflection mode, some of the light beams are absorbed, and the quality of the displayed images is reduced.
What is needed, therefore, is a liquid crystal display panel and a liquid crystal display device that overcome the above-described deficiencies.
An exemplary liquid crystal display panel includes a first substrate, a second substrate opposite to the first substrate, a liquid crystal layer between the first and second substrates, and an electrode layer between the liquid crystal layer and the second substrate. The electrode layer includes a plurality of reflection portions and a plurality of transmission portions. A color filter is disposed between the electrode layer and the second substrate.
An exemplary liquid crystal display device includes a liquid crystal display panel and a backlight module. The liquid crystal display panel includes a first substrate, a second substrate opposite to the first substrate, a liquid crystal layer between the first and second substrates, and an electrode layer between the liquid crystal layer and the second substrate. The first electrode layer includes a plurality of reflection portions and transmission portions. A color filter is disposed between the electrode layer and the second substrate. The backlight module is disposed adjacent to the second substrate.
Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, all the views are schematic.
The second electrode layer 24 includes a multiplicity of reflection portions 241 and a multiplicity of transmission portions 242, which are alternately arranged. The reflection portions 241 are made of highly reflective material, such as aluminum, aluminum alloy, or a like material. The transmission portions 242 are made of transparent material, such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). The first electrode layer 26 is made of transparent material.
In use, when ambient light is strong enough, the liquid crystal display panel 20 is used in a reflection mode. Ambient light beams above the liquid crystal display panel 20 pass through the top substrate 22 and the first electrode layer 26, and irradiate the reflection portions 241. The ambient light beams are reflected by the reflection portions 241, and pass back through the first electrode layer 26 and the top substrate 22 to display images.
When the ambient light is poor, the liquid crystal display panel 20 is used in a transmission mode. Light beams emitted by a backlight (not shown) pass through the color filter 25, the transmission portions 242 and the liquid crystal layer 23, and then transmit out of the top substrate 22 to display images.
The color filter 25 is arranged between the second electrode layer 24 and the bottom substrate 21. The color filter 25 includes a multiplicity of red (R), green (G) and blue (B) portions which are alternately arranged, and a transparent overcoat layer covering and filling gaps between the red, green and blue portions. When the liquid crystal display panel 20 is used in the reflection mode, ambient light beams need not pass through the color filter 25. This decreases the loss of light beams and increases the efficiency of utilization of light beams. Moreover, in the reflection mode, images are display in black and white. This can improve visibility, especially in an environment of strong ambient light.
It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set out in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Number | Date | Country | Kind |
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94211605 | Jul 2005 | TW | national |