JPH0385515A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To allow highlighting which varies in the color and contrast of the specific region of a display surface with simple constitution by varying the double refraction value of the phase difference film of the prescribed region from the double refraction value of the remaining regions. CONSTITUTION:The region which varies in the double refraction value (retardation) is provided on the phase difference film 3 interposed between an analyzer 4 and a glass plate 7. The change in the axis of polarization of the light transmitted through this region is varied from the change in the axis of polarization of the light transmitted through to other regions exclusive of this region. Namely, the degree of the change in the axis of polarization in this region is eventually different from the value in the other regions if the double refraction value of the specific region of the phase difference film 3 is different from the value of the other regions. The light transmitted through the analyzer is colored to colors exclusive of white or black according to the value of n.d of the phase difference film of this region. The display of this region is thus highlighted.

Description

[Detailed description of the invention]

[Summary] Regarding liquid crystal display devices, and in particular regarding liquid crystal panel structures that enable highlighting of specific areas on the display screen, we have developed a new highlighting means that uses a simple configuration to vary the color and contrast of specific areas on the display screen. A super twisted nematic liquid crystal layer is sandwiched between a pair of insulating substrates, and a polarizer is placed on the outside of one of the insulating substrates.
In the configuration of a liquid crystal display device in which a retardation film for color compensation having birefringence and an analyzer are laminated on the outside of the other insulating substrate, and display is performed using the birefringence effect of the liquid crystal layer, a predetermined By making the birefringence value of the retardation film in a region different from that of the remaining regions, the chromaticity and contrast of the region are changed from those of the remaining regions except for the region, and the display is highlighted. [Industrial Field of Application] The present invention relates to a liquid crystal display device, and particularly to a liquid crystal panel structure that enables highlighted display of a specific area on a display screen. [Prior Art] For some time now, characters have been highlighted on a display screen by displaying them in reverse or blinking. In the case of color display devices, this highlighted display has a method of changing the color of the highlighted area to make it easier to identify, but in the case of monochrome LCD panels, it is limited to inverted or blinking display only. . In addition to this, it is also possible to change the chromaticity using a color filter, but this method has the disadvantage that the brightness decreases and the background color and text color change in the same way. This problem similarly exists in FSTN type liquid crystal display devices capable of displaying black and white images. FSTN type liquid crystal display devices use super twisted nematic type liquid crystal (STN type liquid crystal) in which the molecular axes of liquid crystal molecules are twisted in the range of 180 degrees to 270 degrees along the cell layer, and this STN type liquid crystal is attached to a pair of glass plates. A polarizing plate called a polarizer is placed on the outside of one glass plate, and a retardation film and a polarizing plate called an analyzer are laminated on the outside of the other glass plate. The polarization axis of the light that passes through the polarizer rotates before it passes through the liquid crystal and reaches the retardation film, but since the birefringence value of STN liquid crystal is wavelength dependent, red R, green The degree of change in the polarization axis differs between the three primary colors G and blue B. Therefore, if left as is, the display will be colored depending on whether it is on or off. The retardation film is provided to compensate for this difference in changes in polarization axes, and prevents coloring by aligning changes in polarization axes between the three primary colors. Therefore, by adopting the FSTN configuration, a liquid crystal display device with black and white display can be realized. [Problems to be Solved by the Invention] However, even in the above-mentioned FSTN type liquid crystal display device, the emphasis display means is practically limited to inversion or blinking display, and other methods such as color filters are used to display chromaticity. The method of changing the font has the disadvantage that the brightness decreases and the background color and text color change in the same way, so it is not practical. An object of the present invention is to provide a novel highlighting means with a simple configuration. [Means for Solving the Problems] Therefore, the present invention provides a retardation film interposed between an analyzer and a glass plate in an FSTN type liquid crystal display panel, by providing regions with different birefringence values (retardation).
By making the change in the polarization axis of light that passes through this area different from the change in the polarization axis of light that passes through other areas other than this area, the color and contrast of this area can be changed from the color and contrast of other areas. Make it different and highlight it. [Function] The polarization axis of the light that has passed through the polarizer or liquid crystal changes as it passes through the retardation film. Since the degree of change in the polarization axis varies depending on the wavelength of the light, the chromaticity and contrast of the light transmitted through the analyzer change. The value of birefringence is the product Δn-d of the refractive index anisotropy Δn and the thickness d
It is expressed as The degree of change in the polarization axis while light passes through the retardation film differs depending on the wavelength of the light, and also differs depending on the Δn-d of the retardation film. Therefore, if the birefringence value of a specific region of the retardation film is different from that of other regions, the degree of change in the polarization axis of that region will be different from that of the other regions. Therefore, the light transmitted through the analyzer is colored white or a color outside the blackboard depending on the value of Δn-d of the retardation film in that area, so that the display in that area can be emphasized. [Examples] Examples of the present invention will be described in detail below with reference to the drawings.

[First Embodiment] The configuration of the first embodiment of the present invention is shown in FIGS. 1(a) and 1(b).
Shown below. FIG. 5A is a cross-sectional view of a main part, and FIG. 2B is a front view of the display screen. Note that (al indicates a cross section taken along arrow I-1 in (b). As seen in the figure, in this example, the retardation between the polarizer l and the analyzer 4 is 0.95 ±0. 1 μm S
A display STN type liquid crystal panel 2 in which a TN type liquid crystal layer 8 is sandwiched between a pair of glass substrates 7 and 7', and a retardation film 3 for color compensation which has been given birefringence by stretching are laminated,
Furthermore, a highlighting film 5 was interposed in a predetermined region between the color compensation retardation film 3 and the glass substrate 7. In the FSTN liquid crystal panel 2, when the direction that divides the rubbing direction 11 unique to the two glass substrates 7 and 7' into two is 00, the retardation of the color compensation retardation film 3 is 0.60±0. .05 μm, the stretching direction 12 was set at 45 ± 5°, the absorption axis direction 13 of the polarizer 1 was set at -5 ± 5°, and the absorption axis direction 14 of the analyzer 4 was set at 10 ± 5°. . In addition, in this example, according to the propagation of light, the polarizer L ST
An N-type liquid crystal panel 2, a retardation film for color compensation 3, and an analyzer 4 are laminated in this order to enable black and white display. In the FSTN type liquid crystal display device of this embodiment configured as described above, the highlighting film 5 disposed in the area 6 where highlighting is desired (hereinafter simply referred to as the highlighting area) has a retardation of 0.30±0. 02μm and
The stretching direction 15 was set to O±5°. With the configuration described above, in the highlighted display area 6, the characters are displayed in green and the background is displayed in pink. Since the display color of this embodiment is white or black, the highlighted display area 6 is very conspicuous, so that the display is sufficiently emphasized.

[Second Embodiment] Next, the configuration of a second embodiment of the present invention is shown in FIG. 2(a). Shown in (b). FIG. 5A is a cross-sectional view of a main part, and FIG. 2B is a front view of the display screen. In addition, (a) is ('b) ■−■
A cross section taken in the direction of arrows is shown. The embodiment of the wood brush 2 differs from the first embodiment described above only in the retardation film configuration of the highlighting area 6. That is, in this embodiment, the color compensation retardation film 3 is removed from the highlighting area 6, and only the highlighting film 5 is provided. This highlighting film 5 has a retardation of 0.3
0±0.02 μm, and the stretching direction is 12
The angle was 5±5°. With this configuration, in this embodiment, in the highlighted display area 6, the characters are displayed in light blue and the background is yellow, which is easier to identify than black and white display, and provides an effective highlighted display.

[Third Embodiment] Next, the third embodiment of the present invention is shown in FIG.
This is explained by: The same figure (al is a sectional view of the main part, (b) is a front view of the display screen.
A cross section taken in the direction of arrows is shown. This example also applies to the above-mentioned first example. The only difference from the second embodiment is the structure of the retardation film in the highlighted display area 6, and the other structures are the same. The highlighting film 5 used in this example had a retardation of 0.30±0.02 μm and a stretching direction of 125±5°. Furthermore, the highlighted display area 6 is divided into three areas, and in area B, the color compensation retardation film 3 and the above-mentioned emphasis film 5 are divided into three areas.
In the region C, only the highlighting film 5 was provided, and in the other regions, the color compensation retardation film 3 was left removed. Note that area A shown in (a) is the remaining area excluding the highlighted display area. That is, it shows a normal display area. With this configuration, while area A, which is a normal display area, displays black and white, area B, where the color compensation retardation film 3 and the emphasis display film 5 overlap, displays black and white.
In this case, in area C where the background color is purple and the text is yellow, and only the highlighting film 5 is displayed, the background is light blue and the text is yellow, and in the area where there is no retardation film, the background is white and the text is blue. will be displayed. In this embodiment, three types of highlighted display can be obtained in this way. [Effects of the Invention] As explained above, according to the present invention, very conspicuous highlighted display can be obtained with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of the first embodiment of the present invention, FIG. 2 is an explanatory diagram of the configuration of the second embodiment of the invention, and FIG. 3 is an explanatory diagram of the configuration of the third embodiment of the invention. Polarizer, 2 is STN liquid crystal channel, 3 is retardation film for color compensation, 4 is analyzer, 5 is film for highlighting, 6 is highlighting area, 7゜7
” indicates an insulating substrate (glass substrate), and 8 indicates an STN type liquid crystal layer. Pi I No. 11 + 1! Takumei Kaya 2- (Inubukisaka Meisen 2

Claims (4)

[Claims] (1) A super twisted nematic liquid crystal layer (8) is sandwiched between a pair of insulating substrates (7, 7'), a polarizer (1) is placed on the outside of one insulating substrate, and a polarizer (1) is placed on the outside of the other insulating substrate. Retardation film for color compensation with birefringence (3)
In the configuration of a liquid crystal display device in which a birefringence effect of the liquid crystal layer is laminated with an analyzer (4) and a display is performed using the birefringence effect of the liquid crystal layer, the birefringence value of the retardation film in a predetermined area (6) is determined by By making it different from the area, the chromaticity of the area,
1. A liquid crystal display device characterized in that the display is highlighted by changing the contrast of the remaining area except for the area. (2) The retardation film (3) for color compensation is disposed only in the remaining area excluding the predetermined area, so that the birefringence value of the predetermined area is made different from that of the remaining area. The liquid crystal display device according to claim 1. (3) By superimposing another retardation film on the color compensation retardation film in the predetermined area,
2. The liquid crystal display device according to claim 1, wherein the predetermined region has a birefringence value different from that of the remaining regions. (4) By disposing a retardation film in the predetermined region that is different from the retardation film for color compensation disposed in the remaining region excluding the predetermined region, the birefringence value of the predetermined region is A liquid crystal display device characterized by having different areas.