JPS61105583A - Color liquid crystal display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to color filters and liquid crystals, especially twisted
The present invention relates to a color liquid crystal display device that combines a nematic liquid crystal (hereinafter abbreviated as TN liquid crystal) and drives the liquid crystal from a switching element such as a thin film field effect transistor (hereinafter abbreviated as TPT).

(Conventional Structure and Problems thereof) Liquid crystal display devices are thin, driven at low voltage, and have low power consumption, and as a result, market needs for flat panel displays have been rapidly increasing recently. Conventionally, monochrome colors were mainstream, but red, green, and blue (hereinafter referred to as R, G)
A color liquid crystal display device capable of displaying full color using color filters (abbreviated as , B) is also about to be commercialized. In terms of drive, even if the number of scanning lines is increased to increase the resolution of the display, it is possible to display images with excellent contrast and visual dependence, so switching elements such as TPT (thin film transistors) are incorporated to drive the liquid crystal. An active matrix method is also being used.

Figure 1 is a sectional view of the channel part of a conventional color liquid crystal display device, where 1 is a TN liquid crystal, 2a and 2b are T when no voltage is applied.
An alignment film for controlling the initial alignment of the N liquid crystal 1, 3a,
3b is a transparent electrode. The transparent electrode 3b corresponds to a picture element electrode, and is electrically connected to a TPT drain electrode 4b, which will be described later.

4a is a source electrode, 4b is a drain electrode, 5 is a semiconductor,
Reference numeral 6 indicates dirt, and reference numeral 7 indicates an insulating film, and the TPT is constructed by these. The insulating film 7 serves as an r-) insulating layer of the TFT and an insulating layer for the source electrode 4a and r-) 6.

8a, 8b, and 8c are R, G, and B color filters, respectively;
9a and 9b are transparent substrates, 10 is a color filter 8a
, 8b + 8c.

The operation of the conventional color liquid crystal display device configured as described above will be explained.

First, when a scanning signal is applied to the dart 6, the TPT is turned on, conduction occurs between the source electrode 4a and the drain electrode 4b, and the video signal applied from the source electrode 4a charges the liquid crystal layer. Even if the scanning signal disappears, the TPT is turned off, so voltage continues to be applied to the liquid crystal layer between the transparent electrodes 3a and 3b. Since the amount of light transmitted through the liquid crystal layer changes depending on the voltage applied to the liquid crystal layer, it is possible to control the amount of light transmitted by the video signal voltage. The electric charge given to the liquid crystal layer is changed when the next scanning signal is applied to the gate, and the TPT becomes O.
Until the next video signal is applied, leakage occurs through the TPT's OFF resistance and the resistance of the liquid crystal layer, but if both the TPT and liquid crystal have sufficiently large resistances, the leakage will be slight.

The picture element electrodes and the TPTs connected to them are arranged in an IJ box shape, and a scanning signal applied to the gate 6 turns on the TFT groups in the lateral direction all at once to transmit the video signal from the source electrode 4a. It is possible to display an image by writing on it and sequentially scanning it in the vertical direction.

The R, G, and H color filters 8a, gb, and 8c are installed corresponding to the picture element electrodes, and the amount of light transmitted through each of the RlG and B picture elements can be arbitrarily controlled by the applied voltage. Full-color display is possible by additive color mixing of R, G, and H.

However, the conventional method requires a step of forming black stripes that partition the R, G, and B color filters, in addition to the step of forming the color filters. Blank drives are usually blackened and made of Taflom (chromium + chromium oxide) or black dye, but this has the drawbacks of increasing cost and decreasing yield.

Furthermore, when TPT is used as a switching element, it is necessary to provide a light shielding layer for the TPT in order to prevent the switching function from deteriorating due to the photoconductive effect, but this step is also required separately from the color filter forming step.

(Object of the Invention) An object of the present invention is to provide a color liquid crystal display device that eliminates the conventional drawbacks, simplifies the process of forming black stripes and TPT light-shielding layers that partition color filters, and can be manufactured with high yield. It is to be.

In addition, by proactively adopting such a configuration in a liquid crystal display device in which the thickness of the liquid crystal layer is different for R, G, and B, it is possible to provide a color liquid crystal display device with excellent contrast and color reproducibility. be.

(Structure of the Invention) The color liquid crystal display device of the present invention includes a first substrate on which one or more transparent electrodes are formed, and an electrode corresponding to a pixel electrode or a transparent electrode on one principal surface. The electrode group and a second substrate on which a switching element group provided for each picture element electrode for driving the picture element electrodes are formed, facing each other so that the main surface on which the electrodes are formed is the opposing inner surface. A liquid crystal layer is sandwiched in the opposing space, and three types of color filters, red, green, and blue, are arranged on the opposing inner surface of the first substrate in a predetermined manner, corresponding to one type of pixel electrode. The red color filter has a red colored layer, the green color filter has a green colored layer, and the blue color filter has a blue colored layer. Each of the species color filters has two
A light-absorbing layer is defined by light-absorbing stripes formed by overlapping colored layers of different types, and a light-absorbing layer formed of three colored layers and overlapping colored layers in a portion facing the switching element. are formed, and the thickness of the liquid crystal layer corresponding to the red, green, and blue color filters is different, and a voltage is applied to the liquid crystal layer to modulate light.

Further, the thickness of the color filter is different for red, green, and blue.

(Description of Embodiment) An embodiment of the present invention will be described based on FIGS. 2 to 7.

FIG. 2 shows R, G,
FIG. 2 is a configuration diagram of a color filter of H. As can be seen from the figure, the R color filter consists of a layer colored with a red (abbreviated as R in the figure) dye or pigment, and the G color filter consists of a layer colored with a red (abbreviated as R in the figure) dye or pigment. The B color filter consists of two layers: a colored layer made of a yellow (abbreviated as Ye in the figure) dye or pigment, etc., and a colored layer made of a cyan dye or pigment, etc., and a colored layer made of a cyan dye or pigment, etc. It consists of two colored layers made of dyes or pigments (abbreviated).

FIG. 3 is a spectral transmission characteristic diagram of the R, G, and B color filters configured as described above.

Figure 4 shows the arrangement of picture elements, where 11 is the TPT light-shielding part 2 is the picture element part, 13 is the black stripe part, and R, G, H color filters are applied to the picture elements arranged in this way. are installed as shown by R, G, and B in the same figure.

FIG. 5 is a sectional view showing the process of forming a color filter.

First, as shown in Figure 5(,), the R picture element area and the TFT
A colored layer of R is selectively formed on the rack stripe portion at the base of the light shielding portion. The area in which it is formed is shown by a hatched area surrounded by a large frame in the figure, and this is common to a) to d).

Next, as shown in (b), a colored layer of cy is selectively formed on the G picture element part and the B picture element part, and then, as shown in (C), the G picture element part and the TFT A colored layer of the fi light source portion Ye is selectively formed. Finally, a colored layer of B is selectively formed on the B picture element area, the TFT J base area, and the black stripe area (d
). As a result, the black stripe portion has a two-layer structure of overlapping R and B colored layers, and the portion facing the TPT has a three-layer structure of overlapping R, Ye, and B colored layers. In addition, B
A transparent layer may be used in place of the cyan colored layer in the picture element portion.

At this time, the thickness of each colored layer must be adjusted so that the thickness dR, d, , d, of the liquid crystal layer corresponding to each picture element of R, G, and H becomes an optically optimized value. Furthermore, a color filter with excellent optical properties can be obtained. This is to compensate for the optical rotational dispersion of the TN liquid crystal, as stated in Japanese Patent Application No. 16552/1982.

FIG. 6 shows the spectral transmission characteristics of two layers of R and B and three layers of R, Ye, and B. As you can see from this diagram, R and B
The overlapping portion of the two layers is exposed to visible light (400 to 700
The ripples have a light transmittance of 3 μm or less over the entire area, and have excellent light blocking properties, and fully function as a black stripe that improves color separation and contrast. In addition, as shown in the figure, the overlapping portion of the three layers of R, Ye, and B has excellent light speed properties with a light transmittance of 0.5% or less across the entire visible light range, and can be used as a light shielding layer for TPT. Therefore, it is possible to prevent the switching function of the TPT from deteriorating due to the photoconductive effect and ensure good display performance.

FIG. 7 is a sectional view of the 74th channel part of the color liquid crystal display device of the present invention, in which 8d is a red colored layer, 8e is a cyan colored layer, 8
The numbers of each part are the same as in FIG. 1 except that f is a yellow colored layer and 8g is a blue colored layer.

Since its operation is also the same as that of the conventional example, the explanation will be omitted.

Although only a color liquid crystal display device in combination with TPT has been described here, it is also applicable to a case in which it is combined with a nonlinear element such as a MOS-FET. Further, a color liquid crystal display device, which is a combination of a color filter and a liquid crystal, regardless of whether it is a transmissive type or a reverse type, is also included within the scope of the present invention.

(Effects of the Invention) According to the present invention, the black stripes that partition the R, G, and B color filters and the TPT light-shielding layer are arranged in the R, G, and B color filters.
Formed in the same process as the color filter of
This has the effect of simplifying the process, reducing an increase in cost, and suppressing a decrease in yield.

In addition, the black stripe part has a two-layer structure of R and B colored layers, so it has excellent light absorption across the entire visible light range, improves one color separation, and improves contrast. It fully combines the functions of

However, the FET light-shielding part has a three-layer structure of R, Ye, and B colored layers, which has excellent light absorption over the entire visible light range. This has the effect of preventing deterioration of the switching function of the TPT due to this and ensuring good display performance.

Furthermore, with such a configuration, by appropriately adjusting the thickness of the colored layer, the thickness of the liquid crystal layer corresponding to each picture element of R, G, and B can be set to an optically optimum value, and the thickness of the liquid crystal layer corresponding to each picture element of R, G, and B can be set to an optically optimum value. It has the effect of compensating for optical rotation dispersion and providing excellent contrast and color reproducibility.

[Brief explanation of drawings]

Figure 1 is a partial cross-sectional view of the A' channel of a conventional color liquid crystal display device. Figure 2 is a configuration diagram of the R, G, and H color filters. Figure 3 is the spectral transmission of the R, G, and H color filters. Characteristic diagram,
Figure 4 is a pixel arrangement diagram, Figure 5 is a color filter manufacturing process diagram, Figure 6 is a spectral transmission characteristic diagram of two layers of R and B and three layers of R, Ye, and B, and Figure 7 is a diagram of the color filter manufacturing process. 1 is a sectional view of a panel portion of a color liquid crystal display device of the invention. L/TN liquid crystal, 2a, 2b-alignment film, 3a,
3b...Transparent electrode, 4a...Source electrode, 4b...
・Drain electrode, 4d...R colored layer, 4e...cy
Colored layer, 4f...Ye colored layer, 4g...B colored layer,
5... Semiconductor, 6... Dirt, 7... Insulating film, 3
a, 3b, 3a...color filter, 8d, 8e
, 8f, 8g" colored layer, 9a+9b...
・Transparent substrate, 10.13...Black stripe, 1
1...TFT light shielding part, 12...Picture element part. Figure 2

Claims (2)

[Claims] (1) A first substrate on which one or more transparent electrodes are formed on one principal plane, an electrode or a transparent electrode group corresponding to a picture element electrode on one principal plane, and a drive for driving the picture element electrode. and a second substrate on which a switching element group provided for each picture element electrode is formed, are opposed to each other such that the main surface on which the electrodes are formed is the opposing inner surface, and a liquid crystal layer is in the opposing space. A large number of three types of color filters, red, green, and blue, are arranged in a predetermined repetition on the opposing inner surface of the first substrate, one type corresponding to each of the picture element electrodes, The color filter has a red colored layer, the green color filter has a green colored layer, the blue color filter has a blue colored layer,
Each of the three types of color filters, red, green, and blue, is divided by a light-absorbing stripe formed by overlapping two types of colored layers, and the portion facing the switching element has three types of colored layers and a colored layer. A light-absorbing layer composed of overlapping layers is formed, the liquid crystal layers corresponding to the red, green, and blue color filters have different thicknesses, and a voltage is applied to the liquid crystal layer to modulate light. A color liquid crystal display device. (2) The color liquid crystal display device according to claim (1), wherein the color filters have different thicknesses for red, green, and blue.