WO2007073629A1

WO2007073629A1 - An ink-jet type cholesterol liquid crystal device/ color filter and its manufacturing method

Info

Publication number: WO2007073629A1
Application number: PCT/CN2005/002378
Authority: WO
Inventors: Zaoheng Huang; Zhiping Lv
Original assignee: Shanghai Direct Corporation., Ltd.
Priority date: 2005-12-29
Filing date: 2005-12-29
Publication date: 2007-07-05

Abstract

An ink-jet type cholesterol liquid crystal device/ color filter and its manufacturing method, the ink-jet type cholesterol liquid crystal device includes in sequence: an upper substrate, an upper orientation layer, a lower orientation layer, a lower substrate, an upper transparence electrode provided between the upper substrate and the upper orientation layer , a lower transparence electrode and an absorb layer both provided between the lower substrate and the lower orientation layer. Using the ink-jet mode, red, blue, green color cholesterol liquid crystal are jetted respectively to each of the partition walls which is formed on the lower orientation layer to form pixels. Before the ink-jet, the temperature of the cholesterol liquid crystal should be increased in order to decrease the glutinousness of the liquid crystal to a desired range.

Description

Inkjet cholesteric liquid crystal display / color filter and manufacturing method thereof

The present invention relates to a liquid crystal display and a color filter, and more particularly to a high-color-quality full-color cholesterol liquid crystal display using a cholesteric liquid crystal ink-jet method and a high-efficiency color filter using a cholesteric liquid crystal ink-jet method. Background technique

Cholesterol liquid crystal display has bistable characteristics (Bistability). Liquid crystal molecules can exist stably in two states. No continuous voltage is needed to maintain the picture, and it has power saving effect. Therefore, the user only needs to supply voltage when updating the picture. can. Cholesterol liquid crystal display is more energy efficient than general reflective STN or TFT, so it is very suitable for any static display, including large displays (such as advertising billboards, price lists), portable displays (such as electronics). Books, electronic photo frames) and wrap-around displays (electronic paper) and so on.

Cholesterol-type liquid crystals have a storage effect, so the power loss of this display will be lower than that of STN or TN liquid crystal displays. Table 1 summarizes the VGA, 6. 3 吋 full color display in different display technologies for the same battery (5.4 watt-hour). It can be clearly seen from Table 1 that with different reading rates, the battery of the bistable cholesteric liquid crystal display requires different recharging time, and the battery life can reach 1350 hours at a rate of 5 minutes/page. The active matrix addressing, 50% pixel conversion reflective bistable cholesteric liquid crystal display can reach 3200 hours, which is much higher than the real-time update display. Therefore, although cholesterol liquid crystal is not suitable for dynamic picture display, it is excellent in power saving characteristics for displays that are applied to static pictures, and has better performance than STN and active matrix liquid crystal displays in reading e-books. Table 1. A VGA, 6. 3吋 full color display with different display technologies, the required recharge time of the battery

Display Technology Recharge time required for batteries at different reading rates

1 minute / page 2 minutes / page 5 minutes / page

Real-time update of the screen with backlight 2 hours 2 hours 2 hours

Display (such as STN or active matrix STN)

Reflective screen update display in real time 18 hours 18 hours 18 hours

(with power saving electrode)

Reflective bistable cholesteric liquid crystal 270 hours 540 hours 1350 hours

Display (passive matrix addressing)

Reflective bistable cholesteric liquid crystal 640 hours 1280 hours 3200 hours

Display (active matrix addressing, 50%

Pixel conversion) Although cholesteric liquid crystals have many advantages, they are very suitable for use on static screen displays. However, most conventional cholesterol displays are monochromatic, so liquid crystal displays that are inferior to active matrix in display color are rarely used in the market.

〜 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Therefore, red, blue, and green monochromatic cholesteric liquid crystals reflecting specific wavelengths have been developed. Although cholesteric liquid crystals can reflect specific wavelengths, the technology for making full-color displays is complicated and expensive, and is not suitable for the cost considerations of low-cost cholesterol displays.

For traditional color filters, not only is it expensive to manufacture, the cost of moving reticle is millions, and the light-emitting efficiency is about 28% due to its own loss, and the loss of the upper and lower polarizers is about 50%, so the conventional liquid crystal display Only 7% of the light output efficiency. The cholesteric liquid crystal itself has a polarity, so that no additional polarizer is required, so the light extraction efficiency can reach 26.8%, which is much higher than that of the conventional liquid crystal display.

For the prior art of liquid crystal displays, as in US 6,377, 321, it is mainly a liquid crystal layer in which three primary colors of red, green and blue are stacked. However, the parallax will limit the resolution of the device. In order to reduce the parallax, the thickness of the substrate must be less than 0.3 cm. In addition, the size of the pixel is another factor to consider. This superimposed step undoubtedly increases the time and cost of the process. For example, US 6,061,107 uses the different UV light intensity on the liquid crystal layer to control the pitch of the liquid crystal molecules to achieve the three primary colors mixed. This — the process is complex and cannot be done on a single reticle. The third, such as US5, 949, 513, uses the addition of different spins to achieve the effect of mixing light. It can be seen that this method is doping different rotators into the liquid crystal layer to change the pitch of the liquid crystal molecules. However, it is necessary to construct a partition between different color blocks and add different rotators. For example, the Chinese Patent Publication No. 578925 uses a high birefringence diff erence (Δη) liquid crystal material and a simple color filter to set up a full-color cholesteric liquid crystal display. . However, the conventional color filter process is expensive and the liquid crystal having a high birefringence difference is not easily obtained and is more expensive than the conventional single-frequency liquid crystal.

Therefore, it is desired to obtain a cholesteric liquid crystal display and a high-efficiency color filter which are inexpensive, easy to manufacture, and capable of achieving full color. The present invention achieves this object. Summary of the invention

It is an object of the present invention to provide a method for easily coating the desired red, green and blue cholesterol patterns A device and method for producing a high-brightness, power-saving full-color liquid crystal display and a light-efficiency color filter quickly and inexpensively on a glass or plastic substrate that is not limited in size.

The inkjet cholesteric liquid crystal display of the present invention sequentially includes an upper substrate, an upper alignment layer, a lower alignment layer, a lower substrate, and an upper transparent electrode between the upper substrate and the upper alignment layer, and the lower alignment layer and the lower alignment layer a lower transparent electrode and an absorbing layer between the lower substrates. The full-color cholesteric liquid crystal display of the present invention is characterized in that, by means of an ink-jet method, cholesteric liquid crystals of different materials are respectively sprayed out of respective barrier regions on the lower alignment layer to form pixels.

The inkjet cholesteric liquid crystal color filter of the present invention comprises a lower alignment layer, a lower substrate, an upper substrate and an upper alignment layer in sequence, which is characterized in that the cholesterol liquid of different materials is obtained by an inkjet method at an inexpensive price. Phenolic liquid crystal display crystals which are easy and capable of achieving full color purpose are respectively sprayed into the respective barrier regions on the lower alignment layer to form pixels.

The present invention raises the temperature of the cholesteric liquid crystal to lower the viscosity to a desired range before ejecting the cholesteric liquid crystal.

The present invention has two particular advantages: One is that the main feature of the ink jet technology is that it does not require any conventional semiconductor process, and only a computer program is required to control a specific ink-jet area to achieve the desired range of ink ejection. The reduction in the number of masks and the cost of conventional processes represents a significant reduction in the cost of the process; in addition, inkjet technology allows for the most efficient and reliable manufacturing of large-sized substrates and the efficient use of spray materials. The second is that according to the Bragg Reflection principle, the cholesteric liquid crystal itself has optical rotation, so that no polarizer is needed, so that the light-emitting efficiency and the light-emitting brightness are improved, and in terms of color, the cholesteric liquid crystal can pass through the mechanism of the liquid crystal itself. By adjusting the viscosity of the liquid crystal liquid crystal, the color of different reflection wavelengths is exhibited, that is, the color of the liquid crystal liquid crystal can be exhibited from the infrared light band to the visible light band to the ultraviolet light band, so the color performance is excellent. BRIEF abstract

The above and other advantages of the present invention will become more apparent from the detailed description of the appended claims.

Figure 2 is a graph showing the relationship between temperature and viscosity of cholesterol liquid crystal.

Fig. 3 shows a case where the cholesteric liquid crystal by the cholesteric liquid crystal inkjet method is smoothly ejected.

Fig. 4 is a dot pattern formed by a cholesteric liquid crystal inkjet method.

Fig. 5 is a line pattern formed by a cholesteric liquid crystal inkjet method. Figure 6 is a schematic illustration of an embodiment of the invention applied to a high efficiency color filter.

Fig. 7 is a (a) full color pattern formed by a cholesteric liquid crystal ink jet method and (b) a green (c) blue monochromatic cholester liquid crystal display. BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, three different color (red, green, blue) cholesteric liquid crystals are sprayed on a specific retaining wall on a glass or plastic substrate by means of ink jetting, thereby combining the characteristics of ink jet technology and the characteristics of cholesteric liquid crystal. The inkjet cholesteric liquid crystal technology was achieved to produce a full-color cholesteric liquid crystal display and a high-efficiency color filter.

The invention is applied to a cholesteric liquid crystal display, and the structure and principle of the embodiment are as shown in FIG. 1 , wherein 1 is a shower head (inkjet system), 2 is a retaining wall, 3 is a lower glass or plastic substrate, and 4 is a cholesteric liquid crystal. The material, 5 is the lower alignment layer, 6 is the absorption layer, 7 is the upper transparent electrode, 8 is the upper alignment layer, 9 is the upper glass or plastic substrate, and 10 is the lower transparent electrode. The upper transparent electrode 7 is located between the upper substrate 9 and the upper alignment layer 8. The respective barrier walls 2 are disposed on the lower substrate 3 to separate the pixel regions, and are stacked on the lower substrate 3 in the pixel region. The absorbing layer 6, the lower transparent electrode 10, and the lower alignment layer 5 are provided. In the present embodiment, cholesteric liquid crystals of different materials are respectively sprayed onto the lower alignment layer 5 in the respective retaining wall regions by means of an ink jet method.

In the inkjet system 1, a piezoelectric inkjet head is used, (for example, SE-128, and of course, a bubble jet method or a continuous inkjet method), and the reflection wavelength of the cholesteric liquid crystal material 4 for testing. First use a 550 nm green liquid crystal. In order to eject a stable and high-quality droplet of material, the spray head requires that the viscosity of the spray material be in the range of 1 to 15 cps. However, the viscosity of the cholesteric liquid crystal is too high and does not meet the requirements of the model SE-128 head. Therefore, we use the method of raising the temperature, the purpose is to reduce the viscosity of the liquid crystal of the cholesterol to the demand range, and then eject a stable and high-quality droplet material. It has been found from experiments that the viscosity of the liquid crystal of cholesterol and the heating temperature are inversely proportional. As shown in Fig. 2, as the temperature rises, the viscosity of the liquid crystal of the cholesterol drops from 5 to 10 cp _S. When 60 ° C is selected, the viscosity of the cholesteric liquid crystal is lOcps, which is in accordance with the viscosity range of the spray head. After the viscosity requirement is reached, the cholesteric liquid crystal can be smoothly ejected by using the ink jet system 1, as shown in Fig. 3, where la is a spout. This picture shows a snapshot every 15 microseconds. From the picture, the outline of the cholesterol liquid crystal droplets is very clear, and there is no residual image. Therefore, the inkjet head can eject high-stability cholesterol liquid crystal material by heating. . Figure 4 is a sprayed dot pattern of cholesteric liquid crystal having a diameter of 120 microns per dot and lateral and longitudinal spacing of 300 microns and 508 microns, respectively. Thereafter, by continuously ejecting the dot pattern of the cholesteric liquid crystal, a strip pattern as shown in Fig. 5 having a diameter of 120 μm and a longitudinal pitch of 508 μm was obtained. From Figure 4~ In 5, it can be seen that there is no satellite droplet around, so that the liquid crystal can be stably sprayed on the lower alignment layer 5 on the substrate 3 by ink jetting, without material and writing head. A compatible situation occurs.

As described above, the green cholesteric liquid crystal is ejected by spraying two kinds of (point and strip) patterns on the substrate, and other colors (for example, red and blue) can be ejected under different control conditions in the same manner. And any pattern (such as mosaic or triangle) of cholesteric liquid crystal. The cholesteric liquid crystal material is a high birefringence difference reflective cholesteric liquid crystal material which can reflect a wide band spectrum, and is also a reflective cholesteric liquid crystal material which can reflect a narrow band spectrum. The invention is a reflective cholesteric liquid crystal display, which is also a transmissive cholesterol liquid crystal display, or a trans-cholesterol liquid crystal display. The present invention achieves the goal of producing a full color cholesteric liquid crystal display which is efficient and cost effective, has high brightness, high contrast, power saving, storage, wide viewing angle, no flicker, and the like using the cholesterol ink jet technology.

In order to realize the new full-color reflective liquid crystal display process, after the initial substrate and retaining wall system, we successfully sprayed RGB three colors of cholesteric liquid crystal into the cells of the defined retaining wall, as shown in Figure 7. (a), and a panel of the same retaining wall design, printing a 16x160x3 pixels (pixels) 7x7cm ² monochrome panel, as shown in Figure 7. (b) (c). This result achieves our most basic full color concept.

The full-color cholesteric liquid crystal display made by using the cholesterol inkjet technology prepared by the above embodiment is not only cheap, but also simple in method, and its biggest advantage is to save energy, and the average power consumption only needs a penetrating liquid crystal panel. 1/50 or less, it is more power efficient than a general reflective full color STN or TFT. Because cholesterol liquid crystal has a storage function, an e-book made of cholesteric liquid crystal only needs to consume power when turning pages. When the screen is still, it does not need to use electricity. Even if the plug or battery is unplugged, the content of the page can be continuously presented. That is why the ink-jet type cholesterol full-color liquid crystal panel of the present invention is also very suitable for use as an outdoor billboard or a palm-type electronic product that requires power saving.

The invention is applied to a high-efficiency color filter, and its structure and principle are as shown in FIG. 6, wherein 11 is a shower head (inkjet system), 12 is a retaining wall, 13 is a lower alignment layer, 14 is a cholesteric liquid crystal material, 15 is an upper alignment layer, 16 is an upper substrate, and 17 is a lower substrate. In the present embodiment, the red, green, and blue cholesteric liquid crystals are sprayed on the lower aligning layer 13 on the lower substrate 17 of the glass or plastic using the ink jet system 11, and the spraying method is the same as the above-mentioned manufacturing. Color cholesteric liquid crystal display, so no longer repeat them. The dot configurations of the red, blue, and green structures sprayed may be square, triangular, line, or mosaic.

The existing color filter is the most expensive of the key components of the liquid crystal display, and the cost of the mask is turbulent. There are millions of them, but the light-emitting efficiency is about 28% due to the loss of light itself, and the loss of the upper and lower polarizers is about 50%. Therefore, the conventional liquid crystal display can only have a light output efficiency of 7%. Compared with the conventional color filter, the cholesteric liquid crystal itself has a polarity, so that no additional polarizer is required, so the light-emitting efficiency can reach 26.8%, and the estimation is as follows:

Transmittance (%) = backlight X inkjet cholesteric liquid crystal color filter X pixel circuit X lower polarizer

= 100 % X 30 % X 94% X 95 %

= 26. 8 % Industrial Applicability

In summary, the ink jet cholesteric liquid crystal display/color filter produced by the present invention has the following advantages:

1. The inkjet method can easily achieve the required pattern and is not limited to the size, and the traditional process is fast and cost-saving, such as without using the traditional semiconductor process (saving the cost of the mask), by computer program to achieve a specific spray Within the retaining wall of the ink range, the designed ink jet pattern is achieved.

2. High brightness and full color, this cholesterol liquid crystal does not need to use polarizing plate and can pass through the mechanism of liquid crystal itself, can display different wavelengths of color, so it can be used to achieve full cholesterol liquid crystal display (not only power saving) Its light extraction efficiency is superior to liquid crystal displays such as STN and TFT-LCD. In addition, in the color filter application, high light extraction efficiency can be achieved without using a polarizing plate, and the color of RGB can also be achieved by the liquid crystal itself.

All documents mentioned in the present application are hereby incorporated by reference in their entirety in their entireties in the the the the the the the the the In addition, it is to be understood that various modifications and changes may be made by those skilled in the art in the form of the appended claims.

Claims

Rights request

An ink-jet cholesteric liquid crystal display comprising, in order, an upper substrate, an upper alignment layer, a lower alignment layer, a lower substrate, and an upper transparent electrode between the upper substrate and the upper alignment layer, and The lower transparent electrode and the absorbing layer between the alignment layer and the lower substrate are characterized in that: cholesteric liquid crystals are respectively sprayed into the respective barrier regions on the lower alignment layer by inkjet to form pixels.

2. The ink-jet cholesteric liquid crystal display according to claim 1, wherein when the cholesteric liquid crystal of the different material is ejected in the retaining wall region, three narrow frequencies of red, blue and green are ejected. The chrome liquid crystal of the color band material, and the sub-pixels of red, blue and green colors are obtained in the region of the retaining wall, which is a full color cholesteric liquid crystal display.

3. The ink-jet cholesteric liquid crystal display according to claim 1, wherein the cholesteric liquid crystal is sprayed out of the retaining wall region by ejecting a cholesteric liquid crystal of a broadband or narrow-band color band, A sub-pixel of a broadband or narrow-band color band is obtained in the wall area to form a monochrome cholesterol liquid crystal display.

The ink-jet cholesteric liquid crystal display according to claim 1, wherein each of the barrier layer regions includes the lower alignment layer, the lower transparent electrode and the absorption layer, and different materials of cholesterol The liquid crystals are respectively ejected by an ink jet method onto a surface of the lower alignment layer that is not in contact with the lower transparent electrode.

The ink jet cholesteric liquid crystal display according to claim 1, wherein the cholesterol liquid crystal material is a high birefringence difference reflective cholesteric liquid crystal material which can reflect a wide band spectrum.

The ink jet cholesteric liquid crystal display according to claim 1, wherein the cholesteric liquid crystal material is a reflective cholesteric liquid crystal material that reflects a narrow band spectrum.

The ink jet cholesteric liquid crystal display according to claim 1, which is a reflective cholesteric liquid crystal display.

The ink-jet cholesteric liquid crystal display according to claim 1, which is a transmissive cholesteric liquid crystal display.

The ink-jet cholesteric liquid crystal display according to claim 1, which is a trans- cholesteric liquid crystal display.

10. An inkjet cholesteric liquid crystal color filter comprising, in order, a lower alignment layer, a lower substrate, an upper substrate, and an upper alignment layer, wherein: cholesteric liquid crystals of different materials are respectively ejected by the inkjet method Pixels are formed in the respective barrier regions on the alignment layer.

The inkjet cholesteric liquid crystal color filter according to claim 10, wherein the cholesteric liquid crystal of different materials is sprayed out of the retaining wall region by ejecting red, blue and green The cholesteric liquid crystal of the material obtains sub-pixels of three colors of red, blue and green in the region of the retaining wall.

The ink jet cholesteric liquid crystal color filter according to claim 10, wherein the cholesteric liquid crystal of the different material is sprayed on the lower alignment layer which is not in surface contact with the lower substrate.

The ink-jet cholesteric liquid crystal color filter according to claim 10, wherein the red, blue, and green structures of the color filter are arranged in a square shape.

The ink-jet cholesteric liquid crystal color filter according to claim 10, wherein the red, blue, and green structures of the color filter are arranged in a dot shape in a triangular shape.

The ink-jet cholesteric liquid crystal color filter according to claim 10, wherein the red, blue, and green structures of the color filter are arranged in a dot shape in a dot shape.

The ink-jet cholesteric liquid crystal color filter according to claim 10, wherein the red, blue, and green structures of the color filter are arranged in a mosaic shape in a dot shape.

17. A method of manufacturing an ink jet cholesteric liquid crystal display, comprising the steps of:

(1) setting a pixel of each pixel of the liquid crystal display;

(2) first forming an absorbing layer in the area of the retaining wall;

(3) A wide-frequency or narrow-frequency color cholesteric liquid crystal is ejected separately in the retaining wall region by an ink jet method to present a full-color or monochrome image.

18. The method of manufacturing an inkjet cholesteric liquid crystal display according to claim 17, wherein the inkjet method is to spray red, blue, and green cholesterol liquid crystals in the retaining wall region, respectively. Contains the following steps:

(a) raising the temperature to lower the viscosity of the cholesteric liquid crystal to a desired range;

(b) ejecting the viscous liquid crystal of the appropriate viscosity in the area of the retaining wall to present a full-color image.

19. The method of manufacturing an ink-jet cholesteric liquid crystal display according to claim 17, wherein the chromatic liquid crystal of a narrow-band color band or a wide-band color band is ejected in the retaining wall region by an inkjet method. Inside, it also contains the following steps:

(b) ejecting the viscous liquid crystal of the appropriate viscosity in the area of the retaining wall to present a monochromatic image.

A method of manufacturing an ink jet cholesteric liquid crystal display according to claim 17, wherein the display is a wide ribbon cholesteric liquid crystal display.

The method of manufacturing an ink jet cholesteric liquid crystal display according to claim 17, wherein the ink jet method is to eject the cholesteric liquid crystal material by a bubble jet method.

The method of manufacturing an ink jet cholesteric liquid crystal display according to claim 17, wherein the ink jet method is to eject the cholesteric liquid crystal material by a continuous ink jet method.

The method of manufacturing an ink jet cholesteric liquid crystal display according to claim 17, wherein the ink jet method is to eject the cholesteric liquid crystal material by a piezoelectric ink jet method.

24. A method of making an ink jet cholesteric liquid crystal color filter comprising the steps of:

(1) setting pixels on the substrate to a retaining wall;

(2) The red, blue, and green cholesterol liquid crystals are respectively ejected in the respective retaining wall regions by an inkjet method to present a full-color image.

The method of manufacturing an inkjet cholesteric liquid crystal color filter according to claim 24, wherein the red, blue and green cholesteric liquid crystals are respectively ejected in the retaining wall region by an inkjet method , which also includes the following steps:

(2a) raising the temperature, reducing the viscosity of the cholesterol liquid crystal to a range of demand;

(2b) ejecting the viscous liquid crystal of the appropriate viscosity in the area of the retaining wall to present a full-color image.

The method of producing an ink jet cholesteric liquid crystal color filter according to claim 24, wherein the ink jet method is to eject the cholesteric liquid crystal material by a bubble jet method.

The method of producing an ink jet cholesteric liquid crystal color filter according to claim 24, wherein the ink jet method is to eject the cholesteric liquid crystal material by a continuous ink jet method.

The method of producing an ink jet cholesteric liquid crystal color filter according to claim 24, wherein the ink jet method is to eject the cholesteric liquid crystal material by a piezoelectric ink jet method.