TWI823625B - Cholesteric liquid crystal display panel - Google Patents

Abstract

A cholesteric liquid crystal display panel including a first substrate, a second substrate, a first electrode, a second electrode, a third electrode, a fourth electrode and a cholesteric liquid crystal layer is provided. The first substrate overlaps the second substrate. The first electrode and the second electrode are disposed on the first substrate, and are electrically independent from each other. The first electrode has a plurality of first combs. The third electrode and the fourth electrode are disposed on the second substrate, and are electrically independent from each other. The third electrode has a plurality of third combs. An extending direction of the first combs of the first electrode intersects an extending direction of the third combs of the third electrode. The cholesteric liquid crystal layer is disposed between the first substrate and the second substrate, and is suitable for switching between a first state and a second state.

Description

Cholesterol LCD panel

The present invention relates to a liquid crystal panel, and in particular to a cholesteric liquid crystal panel.

In recent years, flexible displays, electronic paper, and e-books have been booming. The display technologies used include cholesteric liquid crystal display technology, electrophoretic display technology, and electrochromic display technology. Compared with other display technologies, cholesteric liquid crystal display technology has the advantages of passive driving characteristics and better brightness and contrast performance, so it has become one of the mainstream technologies for electronic paper applications.

Generally speaking, the molecular alignment state of cholesterol liquid crystals can include two stable alignment states, namely planar state and focal-conic state. When the cholesteric liquid crystal wants to switch from the focal conic state to the planar state, a critical voltage greater than 40 volts must be provided to drive the cholesteric liquid crystal. In addition, since the cholesteric liquid crystal switches from the focal conic state to the planar state, it must first switch to the homeotropic state before it can form a planar state arrangement, resulting in a long switching time between bistable states. In order to make cholesteric liquid crystal suitable for active driving architecture, reducing its bistable switching voltage and switching time is an important issue that needs to be solved.

The invention provides a cholesteric liquid crystal panel, in which the liquid crystal molecules are arranged at a fast switching speed between different stable states and the switching voltage is also low.

The cholesteric liquid crystal panel of the present invention includes a first substrate, a second substrate, a first electrode, a second electrode, a third electrode, a fourth electrode and a cholesteric liquid crystal layer. The first substrate and the second substrate are overlapped with each other. The first electrode and the second electrode are disposed on the first substrate and are electrically independent of each other. The first electrode has a plurality of first comb-shaped parts. The third electrode and the fourth electrode are disposed on the second substrate and are electrically independent of each other. The third electrode has a plurality of third comb-shaped portions. The extending direction of the first comb-shaped portions of the first electrode intersects with the extending direction of the third comb-shaped portions of the third electrode. The cholesteric liquid crystal layer is disposed between the first substrate and the second substrate and is adapted to switch between the first state and the second state.

Based on the above, in the cholesteric liquid crystal panel according to an embodiment of the present invention, a first electrode including a plurality of first comb-shaped parts is provided on the first substrate, and a first electrode including a plurality of second comb-shaped parts is provided on the second substrate. the second electrode. The extending direction of the first comb-shaped parts intersects the extending direction of the second comb-shaped parts. When the first electrode, the second electrode, the third electrode and the fourth electrode are enabled, the horizontal electric field and the vertical electric field formed between these electrodes allow the cholesteric liquid crystal panel to switch between bistable arrangements without going through an intermediate State driven. Therefore, the driving voltage required when the cholesteric liquid crystal panel switches between bistable states can be effectively reduced, and the switching time can also be greatly reduced.

As used herein, "about," "approximately," "substantially," or "substantially" includes the stated value and an average within an acceptable range of deviations from a particular value as determined by one of ordinary skill in the art, taking into account that Discuss the measurement and the specific amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or within ±30%, ±20%, ±15%, ±10%, ±5%, for example. Furthermore, the terms "approximately", "approximately", "substantially" or "substantially" used in this article can be used to select a more acceptable deviation range or standard deviation based on the measurement properties, cutting properties or other properties, and can Not one standard deviation applies to all properties.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. It will be understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element, or Intermediate elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. As used herein, "connected" may refer to physical and/or electrical connections. Furthermore, "electrical connection" can be the presence of other components between the two components.

Additionally, relative terms, such as "lower" or "bottom" and "upper" or "top," may be used herein to describe one element's relationship to another element as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation illustrated in the figures. For example, if the device in one of the figures is turned over, elements described as "lower" than other elements would then be oriented "above" the other elements. Thus, the exemplary term "lower" may include both "lower" and "upper" orientations, depending on the particular orientation of the drawing. Similarly, if the device in one of the figures is turned over, elements described as "below" or "beneath" other elements would then be oriented "above" the other elements. Thus, the exemplary terms "upper" or "lower" may include both upper and lower orientations.

Example embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments. Accordingly, variations in the shapes illustrated in the illustrations are to be expected as a result of, for example, manufacturing techniques and/or tolerances. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, regions shown or described as flat may typically have rough and/or non-linear characteristics. Additionally, the acute angles shown may be rounded. Accordingly, the regions shown in the figures are schematic in nature and their shapes are not intended to illustrate the precise shapes of the regions and are not intended to limit the scope of the claims.

Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numbers are used in the drawings and descriptions to refer to the same or similar parts.

FIG. 1 is a schematic top view of a cholesteric liquid crystal panel according to the first embodiment of the present invention. FIG. 2 is a schematic diagram of some film layers of the cholesteric liquid crystal panel of FIG. 3 . 3 is a schematic cross-sectional view of the cholesteric liquid crystal panel maintained in the first state according to the first embodiment of the present invention. 4 is a schematic cross-sectional view of a cholesteric liquid crystal panel electrically switched from a first state to a second state according to the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of the cholesteric liquid crystal panel maintained in the second state according to the first embodiment of the present invention. 6A and 6B are schematic cross-sectional views of a cholesteric liquid crystal panel electrically switched from a second state to a first state according to the first embodiment of the present invention. 7 is a schematic diagram of the driving waveform when the cholesteric liquid crystal panel is electronically switched from the first state to the second state according to the first embodiment of the present invention. 8A and 8B are schematic diagrams of driving waveforms when the cholesteric liquid crystal panel is electronically switched from the second state to the first state according to the first embodiment of the present invention. For clarity of presentation, the second substrate 102, the cholesteric liquid crystal layer 150 and the spacer 180 of FIG. 3 are omitted from FIG. 1 .

Referring to FIGS. 1 to 3 , the cholesteric liquid crystal panel 10 includes a first substrate 101 , a second substrate 102 , a first electrode E1 , a second electrode E2 , a third electrode E3 , a fourth electrode E4 and a cholesteric liquid crystal layer 150 . The cholesteric liquid crystal layer 150 is disposed between the first substrate 101 and the second substrate 102 and is suitable for switching between the first state and the second state. The first electrode E1 and the second electrode E2 are disposed on the first substrate 101 and are electrically independent of each other. The third electrode E3 and the fourth electrode E4 are disposed on the second substrate 102 and are electrically independent of each other. The first electrode E1 and the second electrode E2 overlap the third electrode E3 and the fourth electrode E4 along the stacking direction of the first substrate 101 and the second substrate 102 (eg, direction D3). In this embodiment, the first electrode E1 and the second electrode E2 may be of the same film layer, and the third electrode E3 and the fourth electrode E4 may be of the same film layer, but are not limited thereto.

In this embodiment, the first electrode E1, the second electrode E2, the third electrode E3 and the fourth electrode E4 are all comb-shaped electrodes, for example. For example, the first electrode E1 has a plurality of first comb-shaped portions E1c, the second electrode E2 has a plurality of second comb-shaped portions E2c, the third electrode E3 has a plurality of third comb-shaped portions E3c, and the fourth electrode E4 It has a plurality of fourth comb portions E4c. However, the present invention is not limited to this. In other embodiments, the first electrode E1 or the second electrode E2 may not have a comb-shaped portion, and the third electrode E3 or the fourth electrode E4 may not have a comb-shaped portion.

In this embodiment, the plurality of first comb-shaped portions E1c of the first electrode E1 and the plurality of second comb-shaped portions E2c of the second electrode E2 may be alternately arranged along the direction D1 (ie, the first direction), and the third electrode The plurality of third comb-shaped portions E3c of E3 and the plurality of fourth comb-shaped portions E4c of the fourth electrode E4 may be alternately arranged along the direction D2 (ie, the second direction), wherein the direction D1 may be selectively perpendicular to the direction D2. From another perspective, the extending directions of the first comb-shaped portion E1c and the second comb-shaped portion E2c intersect (for example, are perpendicular to) the extending directions of the third comb-shaped portion E3c and the fourth comb-shaped portion E4c.

Through the above electrode configuration, the diversity of the electric field directions of the plurality of liquid crystal molecules LC used by the cholesteric liquid crystal panel 10 to drive the cholesteric liquid crystal layer 150 can be increased.

Each of the plurality of first comb-shaped portions E1c and the plurality of second comb-shaped portions E2c has a first width W1 along the direction D1, and any two adjacent ones thereof have a first spacing S1 along the direction D1. For example, in this embodiment, the sum of the first width W1 and the first spacing S1 is 8 microns. Preferably, the first width W1 is in the range of 3.0 microns to 3.2 microns, and the first spacing S1 is in the range of 4.8 microns to 5.0 microns. Optimally, the first width W1 is 3.1 microns, and the first spacing S1 is 4.9 microns.

Similarly, each of the plurality of third comb-shaped portions E3c and the plurality of fourth comb-shaped portions E4c has a second width W2 along the direction D2, and any two adjacent ones thereof have a second spacing S2 along the direction D2. For example, in this embodiment, the sum of the second width W2 and the second spacing S2 is 8 microns. Preferably, the second width W2 is in the range of 3.0 microns to 3.2 microns, and the second spacing S2 is in the range of 4.8 microns to 5.0 microns. Optimally, the second width W2 is 3.1 microns, and the second spacing S2 is 4.9 microns.

It should be noted that the preferred ranges of the width and arrangement spacing of the comb-shaped portions can be adjusted according to different thicknesses and liquid crystal materials of the cholesteric liquid crystal layer 150, and are not limited by the present invention. For example, the width and arrangement pitch of the comb-shaped portions are optimal values when the thickness of the cholesteric liquid crystal layer 150 is 3.7 microns.

On the other hand, the first electrode E1, the second electrode E2, the third electrode E3 and the fourth electrode E4 are, for example, light-transmitting electrodes, and the material of the light-transmitting electrodes includes metal oxides, such as indium tin oxide. , indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, or other suitable oxides, or a stacked layer of at least two of the above.

However, the present invention is not limited to this. In other embodiments, the materials of the first electrode E1, the second electrode E2, the third electrode E3 and the fourth electrode E4 can also be selectively different, for example: the first electrode E1 and the second electrode E2 (or the third electrode E2). The materials of the electrode E3 and the fourth electrode E4) may include metals, alloys, nitrides of metal materials, oxides of metal materials, oxynitrides of metal materials, or other suitable materials, or a combination of metal materials and other conductive materials. Stack layers.

In this embodiment, the plurality of liquid crystal molecules LC of the cholesteric liquid crystal layer 150 can be maintained in two bistable states, which are the first state and the second state. For example, the first state is the focal-conic state 150FC shown in FIG. 3 , and the second state is the planar state 150PL shown in FIG. 5 , but is not limited thereto. The bistable state here means that the liquid crystal molecules LC of the cholesterol liquid crystal layer 150 can form two stable alignment states without applying any electric field. The cholesteric liquid crystal layer 150 is, for example, a nematic liquid crystal doped with a chiral dopant, so the liquid crystal molecules LC are twisted and arranged with a specific pitch.

Specifically, in these two bistable states, the cholesteric liquid crystal layer 150 can exhibit different optical properties. For example, when the cholesteric liquid crystal layer 150 is arranged in a focal cone state 150FC (as shown in FIG. 3 ), diffuse reflection of light will occur, causing the cholesteric liquid crystal layer 150 to appear in a hazy state. When the cholesteric liquid crystal layer 150 is arranged in a planar state 150PL (as shown in Figure 5), it will reflect light of a specific wavelength and allow light of other wavelengths to pass. Among them, the light that can be reflected by the cholesteric liquid crystal layer 150 in the planar state 150PL, Its wavelength depends on the pitch of the cholesteric liquid crystal layer 150 .

For example, the cholesteric liquid crystal panel 10 can be used as a transparent display, in which the wavelength of the reflected light of the cholesteric liquid crystal layer 150 in the planar state 150PL can be designed to be in the infrared band and suitable for allowing visible light to pass through (ie, the transparent state). Therefore, by showing the above-mentioned haze state in a part of the cholesteric liquid crystal layer 150 (for example, the cholesteric liquid crystal layer 150 in this part of the area is maintained in the focal conic state 150FC), and allowing the cholesteric liquid crystal layer 150 in other areas to show a transparent state, You can achieve the effect of transparent display.

The driving method for switching the cholesteric liquid crystal panel 10 between a bistable state (eg, the focal conic state 150FC in FIG. 3 and the planar state 150PL in FIG. 5 ) will be exemplarily described below.

Please refer to Figures 3, 4 and 7. When the cholesteric liquid crystal panel 10 is to switch from the focal conic state 150FC (ie the first state) to the planar state 150PL (ie the second state), the first electrode E1 and the third electrode E3 Being enabled to have a first voltage V1, the second electrode E2 and the fourth electrode E4 are enabled to have a second voltage V2, and the first voltage V1 is different from the second voltage V2. More specifically, the polarity of the driving signal E1_EN applied to the first electrode E1 and the driving signal E3_EN applied to the third electrode E3 will be opposite to the polarity of the driving signal E2_EN applied to the second electrode E2 and the driving signal E2_EN applied to the fourth electrode. The driving signals E4_EN on E4, and these driving signals are, for example, AC signals with a fixed period.

For example, in the time interval of half the cycle, the first voltage V1 is +20V, and the second voltage V2 is −20V; and in the time interval of the other half cycle, the first voltage V1 switches to −20V, and the second voltage V2 is −20V. The second voltage V2 is switched to +20V. Therefore, when the first electrode E1 and the third electrode E3 are respectively supplied with the same drive signal E1_EN and the drive signal E3_EN, and the second electrode E2 and the fourth electrode E4 are supplied with the same drive signal E2_EN and the drive signal E4_EN respectively, , there will be a voltage difference of 40V (ie |V1-V2|) between the second electrode E2 and the fourth electrode E4 and the first electrode E1 and the third electrode E3 respectively. Therefore, as shown in FIG. 4 , a horizontal electric field EFh1 closer to the first substrate 101 will be formed between the first electrode E1 and the second electrode E2, and a horizontal electric field EFh1 closer to the second substrate 102 will be formed between the third electrode E3 and the fourth electrode E4. A horizontal electric field (not shown), a vertical electric field EFv1 will be formed between the first electrode E1 and the fourth electrode E4, and a vertical electric field (not shown) will be formed between the second electrode E2 and the third electrode E3.

The horizontal electric field EFh1 between the first electrode E1 and the second electrode E2 and the horizontal electric field between the third electrode E3 and the fourth electrode E4 can pull the long axis of some liquid crystal molecules LC originally maintained in the focal conic state 150FC back to be more parallel to The orientation of the substrate surface is aligned (eg, the tilt angle relative to the substrate surface is less than 15 degrees). The vertical electric field EFv1 between the first electrode E1 and the fourth electrode E4 and the vertical electric field between the second electrode E2 and the third electrode E3 can pull the long axis of the other part of the liquid crystal molecules LC originally maintained in the focal conic state 150FC toward the longer axis. Arrange in a direction perpendicular to the substrate surface (for example, the tilt angle relative to the substrate surface is greater than 80 degrees). Different from the general switching voltage of 40V for switching from the focal conic state to the planar state, through the simultaneous action of the horizontal electric field and the vertical electric field, the cholesterol liquid crystal layer 150 can be effectively disturbed at a lower voltage (for example, 20V), and in After disabling these electrodes, the cholesterol liquid crystal layer 150 can be transformed into and maintained in a planar state 150PL (as shown in Figures 4 and 5).

From another point of view, in this embodiment, the process of switching the cholesteric liquid crystal panel 10 from the focal conic state 150FC to the planar state 150PL does not need to be driven to the homeotropic state by a high voltage (for example, 40V) first. Only then can it be converted to the planar state 150PL. Therefore, the switching time from the focal conic state 150FC to the planar state 150PL can be effectively reduced, which helps to speed up the update speed of the display screen.

Please refer to Figure 5, Figure 6A and Figure 6B. When the cholesteric liquid crystal panel 10 wants to switch from the planar state 150PL (ie the second state) to the focal conic state 150FC (ie the first state), the first electrode E1 and the second electrode E2 , the third electrode E3 and the fourth electrode E4 can be enabled in two different time intervals in different driving modes.

For example, during the process of switching the cholesteric liquid crystal layer 150 from the second state to the first state, within the first time interval TP1 (as shown in FIG. 8A ), the first electrode E1 and the third electrode E3 are enabled. With the first voltage V1', the second electrode E2 and the fourth electrode E4 are enabled to have the second voltage V2', and the first voltage V1' is different from the second voltage V2'. More specifically, the polarity of the driving signal E1_EN' applied to the first electrode E1 and the driving signal E3_EN' applied to the third electrode E3 will be opposite to the polarity of the driving signal E2_EN' applied to the second electrode E2 and the driving signal E2_EN' applied to the second electrode E2. The driving signals E4_EN' on the fourth electrode E4, and these driving signals are, for example, AC signals with a fixed period.

For example, in the time interval of half the period, the first voltage V1' may be a positive bias voltage less than 10V, and the second voltage V2' may be a negative bias voltage less than 10V; and in the time interval of the other half period , the first voltage V1' may be a negative bias voltage less than 10V, and the second voltage V2' may be a positive bias voltage less than 10V. Therefore, when the first electrode E1 and the third electrode E3 are respectively applied with the same driving signal E1_EN' and the driving signal E3_EN', and the second electrode E2 and the fourth electrode E4 are respectively applied with the same driving signal E2_EN' and the driving signal When the signal E4_EN' is activated, the voltage difference between the second electrode E2 and the fourth electrode E4 and the first electrode E1 and the third electrode E3 is less than 20V (ie, |V1'-V2'|). Therefore, as shown in FIG. 6A , a horizontal electric field EFh2 closer to the first substrate 101 will be formed between the first electrode E1 and the second electrode E2, and a horizontal electric field EFh2 closer to the second substrate 102 will be formed between the third electrode E3 and the fourth electrode E4. horizontal electric field (not shown).

In the first time interval TP1, through the above-mentioned horizontal electric field, some of the liquid crystal molecules LC originally maintained in the planar state 150PL (especially the liquid crystal molecules LC closer to the first substrate 101 and the second substrate 102) are first disturbed to form Arrangements of focal conic states. In particular, in order to prevent the cholesteric liquid crystal panel 10 from being squeezed by an external force and causing the first substrate 101 and the second substrate 102 to come close to each other and thereby affecting the film thickness uniformity of the cholesteric liquid crystal layer 150 , the cholesteric liquid crystal panel 10 may also be provided with a gap 180 . In this embodiment, the spacer 180 may be disposed on the second substrate 102, but is not limited thereto. In another embodiment, the spacer 180 may also be disposed on the first substrate 101 .

Since some of the liquid crystal molecules LC between the spacer 180 and the first substrate 101 of the cholesterol liquid crystal layer 150 are difficult to be driven by the vertical electric field, even if other parts of the liquid crystal molecules LC are driven by the vertical electric field, they are arranged in a focal cone state (i.e., a fog state). When the liquid crystal molecules LC overlap with the gap 180 along the direction D3, they are still arranged in a planar state (ie, a transparent state), causing problems of light leakage and contrast reduction.

Therefore, unlike the known method that only uses a vertical electric field to switch from the planar state to the focal conic state, the cholesteric liquid crystal panel 10 of this embodiment first uses a horizontal electric field to disturb the cholesteric liquid crystal layer 150 with the interstitial object in the first time interval TP1 Some of the liquid crystal molecules LC between 180 and the first substrate 101 can effectively switch the arrangement of this part of the liquid crystal molecules LC from a planar state to a focal conic state (as shown in Figure 6A). In other words, the overall haze of the cholesteric liquid crystal panel 10 when maintained at the focal conic state 150FC can be improved, thereby increasing the display contrast.

Furthermore, during the process of switching the cholesteric liquid crystal layer 150 from the second state to the first state, within the second time interval TP2 (as shown in FIG. 8B ), the first electrode E1 and the second electrode E2 are enabled. With the third voltage V3, the third electrode E3 and the fourth electrode E4 are enabled to have the fourth voltage V4, and the third voltage V3 is different from the fourth voltage V4. For example, in the time interval of half the period, the third voltage V3 may be a positive bias voltage less than 20V, and in the time interval of the other half period, the third voltage V3 may be a negative bias voltage less than 20V. More specifically, the driving signal E1_EN" applied to the first electrode E1 and the driving signal E2_EN" applied to the second electrode E2 are AC signals with a fixed period. Different from the driving signal E1_EN" and the driving signal E2_EN", the driving signal E3_EN" applied to the third electrode E3 and the driving signal E4_EN" applied to the fourth electrode E4 are direct current signals with a fixed potential (eg, ground potential).

Therefore, when the first electrode E1 and the second electrode E2 are respectively applied with the same driving signal E1_EN" and the driving signal E2_EN", and the third electrode E3 and the fourth electrode E4 are respectively applied with the same driving signal E3_EN" and the driving signal When the signal E4_EN" is activated, the voltage difference between the first electrode E1 and the second electrode E2 and the third electrode E3 and the fourth electrode E4 is less than 20V (ie, |V3-V4|). Therefore, as shown in FIG. 6B , a vertical electric field EFv2 is formed between the first electrode E1 and the second electrode E2 and the third electrode E3 and the fourth electrode E4 respectively.

In the second time interval TP2, the liquid crystal molecules LC between the upper electrode (ie, the third electrode E3 or the fourth electrode E4) and the lower electrode (ie, the first electrode E1 or the second electrode E2) can be caused by the above-mentioned vertical electric field EFv2. is perturbed to form an arrangement of the focal cone state (as shown in Figure 6B). In this embodiment, the second time interval TP2 may be after the first time interval TP1, but is not limited to this. In another modified embodiment, the first time interval TP1 may also be after the second time interval TP2.

In particular, the absolute value of the difference between the first voltage V1 and the second voltage V2 in FIG. 7 (i.e., |V1-V2|) is greater than the difference between the third voltage V3 and the fourth voltage V4 in FIG. 8B. The absolute value (i.e. |V3-V4|), and the absolute value of the difference between the third voltage V3 and the fourth voltage V4 in Figure 8B is greater than the difference between the first voltage V1' and the second voltage V2' in Figure 8A The absolute value of (i.e. |V1'-V2'|).

Other embodiments will be enumerated below to describe the present invention in detail, in which the same components will be marked with the same symbols, and descriptions of the same technical content will be omitted. Please refer to the previous embodiments for the omitted parts, which will not be described again.

9 and 10 are schematic top views of the first electrode, the second electrode, the third electrode and the fourth electrode according to another modified embodiment of the present invention. Please refer to Figure 9. Different from the first electrode E1 to the fourth electrode E4 in Figure 1, in another modified embodiment, the first electrode E1-A has a first connection part E1m1, a second connection part E1m2, a plurality of One comb-shaped portion E1c1 and a plurality of first comb-shaped portions E1c2. In this embodiment, the first connection part E1m1 and the second connection part E1m2 are respectively disposed on opposite sides of the second electrode E2, and the plurality of first comb-shaped parts E1c1 are directed from the first connection part E1m1 toward the second electrode E2-A. extends out, and a plurality of first comb-shaped portions E1c2 extend from the second connection portion E1m2 toward the second electrode E2-A.

On the other hand, the second electrode E2-A has a connection part E2m, a plurality of second comb-shaped parts E2c1, and a plurality of second comb-shaped parts E2c2. These second comb-shaped portions E2c1 extend from the connection portion E2m toward the first connection portion E1m1 of the first electrode E1-A. These second comb-shaped portions E2c2 extend from the connection portion E2m toward the second connection portion E1m2 of the first electrode E1-A. More specifically, the plurality of first comb-shaped portions E1c1 of the first electrode E1-A and the plurality of second comb-shaped portions E2c1 of the second electrode E2-A are alternately arranged along the direction D1. A plurality of first comb-shaped portions E1c2 and a plurality of second comb-shaped portions E2c2 of the second electrode E2-A are alternately arranged along the direction D1. It is particularly noteworthy that the arrangement positions of the plurality of first comb-shaped portions E1c1 in the direction D1 are staggered to the plurality of first comb-like portions E1c2, and the arrangement positions of the plurality of second comb-like portions E2c1 in the direction D1 are staggered to the plurality of first comb-like portions E1c2. Second comb E2c2.

Referring to FIG. 10 , similarly, the fourth electrode E4 -A has a first connection part E4m1 , a second connection part E4m2 , a plurality of fourth comb-shaped parts E4c1 and a plurality of fourth comb-shaped parts E4c2 . In this embodiment, the first connection part E4m1 and the second connection part E4m2 of the fourth electrode E4-A are respectively disposed on opposite sides of the third electrode E3-A, and the plurality of fourth comb-shaped parts E4c1 are connected from the first The portion E4m1 extends toward the third electrode E3-A, and the plurality of fourth comb-shaped portions E4c2 extends from the second connection portion E4m2 toward the third electrode E3-A.

The third electrode E3-A has a connection part E3m, a plurality of third comb-shaped parts E3c1, and a plurality of third comb-shaped parts E3c2. These third comb-shaped portions E3c1 extend from the connection portion E3m toward the first connection portion E4m1 of the fourth electrode E4-A. These third comb-shaped portions E3c2 extend from the connection portion E3m toward the second connection portion E4m2 of the fourth electrode E4-A. More specifically, the plurality of third comb-shaped portions E3c1 of the third electrode E3-A and the plurality of fourth comb-shaped portions E4c1 of the fourth electrode E4-A are alternately arranged along the direction D2. A plurality of third comb-shaped portions E3c2 and a plurality of fourth comb-shaped portions E4c2 of the fourth electrode E4-A are alternately arranged along the direction D2. It is particularly noted that the arrangement positions of the plurality of third comb-shaped parts E3c1 in the direction D2 are staggered to the plurality of third comb-shaped parts E3c2, and the arrangement positions of the plurality of fourth comb-shaped parts E4c1 in the direction D2 are staggered to the plurality of third comb-like parts E3c2. The fourth comb E4c2.

Please refer to Figures 9 and 10. Similar to the first electrode E1 to the fourth electrode E4 in Figure 1, in this embodiment, the first comb-shaped portion E1c1 and the first comb-shaped portion E1c2 of the first electrode E1-A and The respective extension directions of the second comb-shaped portion E2c1 and the second comb-shaped portion E2c2 of the second electrode E2-A may intersect (eg, perpendicular to) the third comb-shaped portion E3c1 and the third comb-shaped portion of the third electrode E3-A. E3c2 and the respective extending directions of the fourth comb-shaped portions E4c1 and E4c2 of the fourth electrode E4-A.

Since the first electrode E1 -A to the fourth electrode E4 -A of this embodiment can be used to replace the first electrode E1 to the fourth electrode E4 of FIG. 1 , regarding the driving method of these electrodes, please refer to the relevant paragraphs of the foregoing embodiment. This will not be repeated again.

11 and 12 are schematic top views of the first electrode, the second electrode, the third electrode and the fourth electrode according to another modified embodiment of the present invention. Please refer to FIG. 11 . Different from the previous embodiment, in this embodiment, the extending direction (for example, direction D2 ′) of the plurality of first comb-shaped portions E1c-B of the first electrode E1-B can be inclined to the connecting portion E1m- B (for example, direction D1), the extension direction (for example, direction D2') of the plurality of second comb-shaped portions E2c-B of the second electrode E2-B may be inclined to the extension direction (for example, direction D2') of the connecting portion E2m-B. D1). The alternating arrangement direction (for example, direction D1') of the plurality of first comb-shaped portions E1c-B and the plurality of second comb-shaped portions E2c-B is also inclined to the extending direction of the connecting portion E1m-B.

Referring to FIG. 12 , similarly, the extending direction (eg, direction D1 ′) of the plurality of third comb-shaped portions E3c-B of the third electrode E3-B may be inclined to the extending direction (eg, direction D2) of the connecting portion E3m-B. , the extension direction (for example, the direction D1') of the plurality of fourth comb-shaped portions E4c-B of the fourth electrode E4-B may be inclined to the extension direction (for example, the direction D2) of the connection portion E4m-B (or the connection portion E3m-B). ). The alternating arrangement direction (for example, direction D2') of the plurality of third comb-shaped portions E3c-B and the plurality of fourth comb-shaped portions E4c-B is also inclined to the extending direction of the connecting portion E4m-B (or the connecting portion E3m-B). (e.g. direction D2).

Since the first electrode E1 -B to the fourth electrode E4 -B of this embodiment can be used to replace the first electrode E1 to the fourth electrode E4 of FIG. 1 , regarding the driving method of these electrodes, please refer to the relevant paragraphs of the aforementioned embodiment. This will not be repeated again.

13 and 14 are schematic top views of the first electrode, the second electrode, the third electrode and the fourth electrode according to yet another modified embodiment of the present invention. Please refer to Figure 13. Different from the first electrode E1-A and the second electrode E2-A in Figure 9, the first electrode E1-C in this embodiment extends from the first connection part E1m1-C or the second connection part E1m2. The plurality of first comb-shaped portions of -C may have different extending directions, and the plurality of second comb-shaped portions of the second electrode E2-C extending from the connecting portion E2m-C may have different extending directions.

For example, the extension direction (for example, direction D2') of the first comb-shaped portion E1c11 extending from the first connecting portion E1m1-C and the extension direction (for example, direction D2") of the first comb-shaped portion E1c12 intersect with each other, and both Inclined to the extension direction (for example, direction D1) of the first connection part E1m1-C. The extension direction (for example, direction D2") of the first comb-shaped part E1c21 extending from the second connection part E1m2-C and the first comb-shaped part E1c22 The extension directions (for example, direction D2') of the second connecting portion E1m2-C intersect with each other, and are all inclined to the extension direction (for example, direction D1) of the second connecting portion E1m2-C. It is particularly noted that the first electrode E1-C also has a tapered portion E1c3 extending from the first connection portion E1m1-C and a tapered portion E1c4 extending from the second connection portion E1m2-C.

On the other hand, the extension direction of the second comb-shaped portion E2c11 (for example, direction D2') extending from the connection portion E2m-C toward the first connection portion E1m1-C and the extension direction of the second comb-shaped portion E2c12 (for example, the direction D2″ ) intersect with each other and are inclined to the extension direction (for example, direction D1) of the connecting portion E2m-C. The extension direction (for example, the direction D2") and the extension direction of the second comb-shaped portion E2c22 (for example, direction D2') intersect each other, and are both inclined to the extension direction of the connecting portion E2m-C (for example, direction D1).

Please refer to Figure 14. Different from the third electrode E3-A and the fourth electrode E4-A of Figure 10, the third electrode E3-C of this embodiment has a plurality of third combs extending from the first connection portion E3m-C. The comb-shaped portions may have different extending directions, and the plurality of second comb-shaped portions extending from the first connecting portion E4m1-C or the second connecting portion E4m2-C in the fourth electrode E4-C may have different extending directions.

For example, the extension direction of the third comb-shaped portion E3c11 extending from the connection portion E3m-C toward the first connection portion E4m1-C (for example, the direction D1″) and the extension direction of the third comb-shaped portion E3c12 (for example, the direction D1′ ) intersect with each other and are inclined to the extension direction (for example, direction D2) of the connecting portion E3m-C. The extension direction (for example, the direction D1') and the extension direction of the third comb-shaped portion E3c22 (for example, direction D1") intersect each other, and are both inclined to the extension direction of the connecting portion E3m-C (for example, direction D2). It is particularly noted that the third electrode E3-C also has a tapered portion E3c3 extending from the connecting portion E3m-C and toward the first connecting portion E4m1-C, and a tapered portion E3c3 extending from the connecting portion E3m-C and toward the second connecting portion E4m2- The cone of C is E3c4.

On the other hand, in the fourth electrode E4-C, the extending direction of the fourth comb-shaped portion E4c11 extending from the first connection portion E4m1-C (for example, the direction D1″) and the extending direction of the fourth comb-shaped portion E4c12 (for example, the direction D1 ') intersect each other and are inclined to the extension direction (for example, direction D2) of the first connection portion E4m1-C. The extension of the fourth comb-shaped portion E4c21 of the fourth electrode E4-C extending from the second connection portion E4m2-C The direction (eg, direction D1 ′) and the extension direction (eg, direction D1 ″) of the fourth comb-shaped portion E4c22 intersect each other, and are both inclined to the extension direction (eg, direction D2 ) of the second connecting portion E4m2 -C.

Since the first electrode E1 -C to the fourth electrode E4 -C of this embodiment can be used to replace the first electrode E1 to the fourth electrode E4 of FIG. 1 , for the driving method of these electrodes, please refer to the relevant paragraphs of the aforementioned embodiment. This will not be repeated again.

FIG. 15 is a schematic cross-sectional view of a cholesteric liquid crystal panel according to the second embodiment of the present invention. FIG. 16 is a schematic top view of some film layers of the cholesteric liquid crystal panel of FIG. 15 . Please refer to Figures 15 and 16. Different from the cholesteric liquid crystal panel 10 of Figure 3, the first electrode E1-D and the second electrode E2-D of the cholesteric liquid crystal panel 20 of this embodiment belong to different film layers, and the third electrode E3 -D and the fourth electrode E4-D belong to different film layers. For the sake of clarity, FIG. 16 only shows the first substrate 101, the first electrode E1-D, the second electrode E2-D, the third electrode E3-D and the fourth electrode E4-D of FIG. 15 .

In detail, the first electrode E1-D and the third electrode E3-D are surface electrodes, and overlap with the second electrode E2-D and the fourth electrode E4-D along the direction D3. In order to ensure the electrical independence between the first electrode E1-D and the second electrode E2-D, an insulating layer INS1 may be provided between the first electrode E1-D and the second electrode E2-D. Similarly, an insulating layer INS2 may be disposed between the third electrode E3-D and the fourth electrode E4-D to ensure electrical independence between them.

Since the first electrode E1 -D to the fourth electrode E4 -D of this embodiment can be used to replace the first electrode E1 to the fourth electrode E4 of FIG. 1 , regarding the driving method of these electrodes, please refer to the relevant paragraphs of the foregoing embodiment. This will not be repeated again.

To sum up, in the cholesteric liquid crystal panel according to an embodiment of the present invention, the first electrode including a plurality of first comb-shaped portions is provided on the first substrate, and the second substrate is provided with a plurality of second comb-shaped portions. The second electrode of the shape part. The extending direction of the first comb-shaped parts intersects the extending direction of the second comb-shaped parts. When the first electrode, the second electrode, the third electrode and the fourth electrode are enabled, the horizontal electric field and the vertical electric field formed between these electrodes allow the cholesteric liquid crystal panel to switch between bistable arrangements without going through an intermediate State driven. Therefore, the driving voltage required when the cholesteric liquid crystal panel switches between bistable states can be effectively reduced, and the switching time can also be greatly reduced.

10, 20: Cholesterol LCD panel 101: First substrate 102: Second substrate 150: Cholesterol liquid crystal layer 150FC: Focus cone state 150PL: Planar state 180: Gap D1, D2, D3, D1’, D2’, D1”, D2”: direction E1, E1-A, E1-B, E1-C, E1-D: first electrode E1c, E1c1, E1c2, E1c-B, E1c11, E1c12, E1c21, E1c22: first comb E1c3, E1c4, E3c3, E3c4: Cone E1m-B, E2m-B, E3m-B, E4m-B, E2m, E2m-C, E3m, E3m-C: Connection part E1m1, E1m1-C, E4m1-C: first connection part E1m2, E1m2-C, E4m2-C: second connection part E1_EN, E2_EN, E3_EN, E4_EN, E1_EN’, E2_EN’, E3_EN’, E4_EN’, E1_EN”, E2_EN”, E3_EN”, E4_EN”: drive signal E2, E2-A, E2-B, E2-C, E2-D: second electrode E2c, E2c1, E2c2, E2c-B, E2c11, E2c12, E2c21, E2c22: second comb E3, E3-A, E3-B, E3-C, E3-D: third electrode E3c, E3c1, E3c2, E3c-B, E3c11, E3c12, E3c21, E3c22: third comb E4, E4-A, E4-B, E4-C, E4-D: fourth electrode E4c, E4c1, E4c2, E4c-B, E4c11, E4c12, E4c21, E4c22: the fourth comb E4m1: First connection part E4m2: Second connection part EFh1, EFh2: horizontal electric field EFv1, EFv2: vertical electric field INS1, INS2: insulation layer S1: first spacing S2: second spacing TP1: first time interval TP2: The second time interval V1, V1’: first voltage V2, V2’: second voltage V3: The third voltage V4: fourth voltage W1: first width W2: second width

FIG. 1 is a schematic top view of a cholesteric liquid crystal panel according to the first embodiment of the present invention. FIG. 2 is a schematic diagram of some film layers of the cholesteric liquid crystal panel of FIG. 3 . 3 is a schematic cross-sectional view of the cholesteric liquid crystal panel maintained in the first state according to the first embodiment of the present invention. 4 is a schematic cross-sectional view of a cholesteric liquid crystal panel electrically switched from a first state to a second state according to the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of the cholesteric liquid crystal panel maintained in the second state according to the first embodiment of the present invention. 6A and 6B are schematic cross-sectional views of a cholesteric liquid crystal panel electrically switched from a second state to a first state according to the first embodiment of the present invention. 7 is a schematic diagram of the driving waveform when the cholesteric liquid crystal panel is electronically switched from the first state to the second state according to the first embodiment of the present invention. 8A and 8B are schematic diagrams of driving waveforms when the cholesteric liquid crystal panel is electronically switched from the second state to the first state according to the first embodiment of the present invention. 9 and 10 are schematic top views of the first electrode, the second electrode, the third electrode and the fourth electrode according to another modified embodiment of the present invention. 11 and 12 are schematic top views of the first electrode, the second electrode, the third electrode and the fourth electrode according to another modified embodiment of the present invention. 13 and 14 are schematic top views of the first electrode, the second electrode, the third electrode and the fourth electrode according to yet another modified embodiment of the present invention. FIG. 15 is a schematic cross-sectional view of a cholesteric liquid crystal panel according to the second embodiment of the present invention. FIG. 16 is a schematic top view of some film layers of the cholesteric liquid crystal panel of FIG. 15 .

10: Cholesterol LCD panel

101: First substrate

D1, D2, D3: direction

E1: first electrode

E1c: first comb

E2: second electrode

E2c: Second comb

E3: The third electrode

E3c: third comb

E4: The fourth electrode

E4c: fourth comb

S1: first spacing

S2: second spacing

W1: first width

W2: second width

Claims (12)

A cholesteric liquid crystal panel includes: a first substrate and a second substrate, which are arranged to overlap each other; a first electrode and a second electrode, which are arranged on the first substrate and are electrically independent of each other, and the first electrode has A plurality of first comb-shaped parts; a third electrode and a fourth electrode, which are disposed on the second substrate and are electrically independent of each other; the third electrode has a plurality of third comb-shaped parts, wherein the first electrode The extension direction of the first comb-shaped parts intersects the extension direction of the third comb-shaped parts of the third electrode; and a cholesteric liquid crystal layer is provided between the first substrate and the second substrate, the The cholesteric liquid crystal layer is adapted to switch between a first state and a second state, wherein the first state is a focal conic state and the second state is a planar state. When the first electrode and the third electrode are enabled When there is a first voltage V1 and the second electrode and the fourth electrode are enabled to have a second voltage V2, the cholesteric liquid crystal layer switches from the first state to the second state, the first voltage V1 is different from the second voltage V2. The cholesteric liquid crystal panel according to claim 1, wherein the second electrode has a plurality of second comb-shaped parts, the fourth electrode has a plurality of fourth comb-shaped parts, and the first comb-shaped parts and the second comb-shaped parts are The comb-shaped parts are alternately arranged along a first direction, the third comb-shaped parts and the fourth comb-shaped parts are alternately arranged along a second direction, and the first direction is perpendicular to the second direction. The cholesteric liquid crystal panel of claim 2, wherein the first electrode and the second electrode are in the same film layer, and the third electrode and the fourth electrode are in the same film layer. The cholesteric liquid crystal panel of claim 1, wherein when the first electrode, the second electrode, the third electrode and the fourth electrode are disabled, the cholesteric liquid crystal layer remains in the second state. The cholesteric liquid crystal panel as claimed in claim 1, wherein during the switching of the cholesteric liquid crystal layer from the second state to the first state, the first electrode and the third electrode are connected within a first time interval. The second electrode and the fourth electrode are enabled to have a first voltage V1', and the second electrode and the fourth electrode are enabled to have a second voltage V2', and the first voltage V1' is different from the second voltage V2'. The cholesteric liquid crystal panel of claim 5, wherein during the switching of the cholesteric liquid crystal layer from the second state to the first state, within a second time interval, the first electrode and the second electrode are The third electrode and the fourth electrode are enabled to have a third voltage V3, and the third electrode and the fourth electrode are enabled to have a fourth voltage V4, and the third voltage V3 is different from the fourth voltage V4. The cholesteric liquid crystal panel of claim 6, wherein the absolute value of the difference between the first voltage V1 and the second voltage V2 is greater than the absolute value of the difference between the third voltage V3 and the fourth voltage V4, and the The absolute value of the difference between the third voltage V3 and the fourth voltage V4 is greater than the absolute value of the difference between the first voltage V1' and the second voltage V2'. The cholesteric liquid crystal panel of claim 6, wherein the second time interval is after the first time interval. The cholesteric liquid crystal panel of claim 6, wherein when the first electrode, the second electrode, the third electrode and the fourth electrode are disabled, the cholesteric liquid crystal layer remains in the first state. The cholesteric liquid crystal panel of claim 2, wherein each of the first comb-shaped portions and the second comb-shaped portions has a first width along the first direction, and the first comb-shaped portions and the second comb-shaped portions have a first width along the first direction. Any two adjacent ones of the second comb-shaped parts have a first spacing along the first direction, the sum of the first width and the first spacing is 8 microns, and the first width is between 3.0 microns and 3.2 microns. range, and the first pitch is in the range of 4.8 microns to 5.0 microns. The cholesteric liquid crystal panel of claim 10, wherein each of the third comb-shaped parts and the fourth comb-shaped parts has a second width along the second direction, and the third comb-shaped parts and the fourth comb-shaped parts have a second width along the second direction. Any two adjacent ones of the fourth comb-shaped parts have a second spacing along the second direction, the sum of the second width and the second spacing is 8 microns, and the second width is between 3.0 microns and 3.2 microns. range, and the second pitch is in the range of 4.8 microns to 5.0 microns. The cholesteric liquid crystal panel of claim 1, wherein the first electrode and the second electrode belong to different film layers, the third electrode and the fourth electrode belong to different film layers, and the first electrode and the third electrode Each overlaps the second electrode and the fourth electrode.