TWI792689B - Cholesterol liquid crystal display device - Google Patents

Abstract

A cholesteric liquid crystal display device includes writing terminals and scanning terminals. The writing terminals are arranged along the first direction and have a bright voltage and a dark voltage. The scanning terminals are arranged along the second direction and have a selected voltage and a non-selected voltage. The writing terminals and the scanning terminals cross each other to form a plurality of intersections. The electrical signal at each intersection is used to control the pixels. The absolute value of the difference between the bright voltage and the non-selected voltage in the same time period is defined as the first voltage difference. The absolute value of the difference between the dark voltage and the non-selected voltage in the same time period is defined as the second voltage difference. The second voltage difference is smaller than the first voltage difference. Thereby, the cholesteric liquid crystal display device can avoid the occurrence of Crosstalk on the cholesteric liquid crystal display device.

Description

Cholesteric liquid crystal display device

The invention relates to the technical field of liquid crystal display, in particular to a cholesteric liquid crystal display device.

Cholesteric liquid crystal display is a kind of liquid crystal display, in which cholesteric liquid crystal has bistable characteristics: that is to say, there are two stable states when no external force is applied, which is the biggest difference with the TFT liquid crystal display and OLED display commonly used today. difference.

The arrangement of cholesteric liquid crystal molecules has two stable states: focal conic state (Focal Conic State) and planar state (Planar State), so it has bistable characteristics, that is, cholesteric liquid crystals can maintain the original state without external energy. Alignment state of liquid crystal molecules. When a voltage is applied, the alignment state of the cholesteric liquid crystal molecules can be controlled to switch between the focal conic alignment state and the planar alignment state.

The current cholesteric liquid crystal display usually has a Crosstalk problem, which interferes with the display status of the picture. Crosstalk means that in the case of multi-channel voltage driving, when a voltage is applied to a selected pixel, the nearby unselected pixels will show a certain display state due to the influence of leakage current. That is to say, other pixels around the selected pixel will also show a certain display state, causing interference.

Therefore, the main purpose of the present invention is to provide a cholesteric liquid crystal display device to solve the above problems.

The object of the present invention is to provide a cholesteric liquid crystal display device, which can prevent Crosstalk from occurring on the cholesteric liquid crystal display device, prevent unselected pixels from displaying a display state, and ensure the display performance of the cholesteric liquid crystal display device.

In order to achieve at least one of the above advantages or other advantages, an embodiment of the present invention provides a cholesteric liquid crystal display device. The cholesteric liquid crystal display device includes a plurality of writing terminals and a plurality of scanning terminals.

The plurality of writing terminals are arranged along a first direction, and have a bright state voltage and a dark state voltage. The plurality of scanning terminals are arranged along a second direction, and have a selected state voltage and a non-selected state voltage. The writing terminals and the scanning terminals intersect each other to form a plurality of intersections, and the electrical signal at each intersection is used to control a pixel. Wherein, the absolute value of the difference between the bright state voltage and the non-selected state voltage in the same time period is defined as the first voltage difference, and the absolute value of the difference between the dark state voltage and the non-selected state voltage in the same time period is defined as is a second voltage difference, and the second voltage difference is smaller than the first voltage difference.

In some embodiments, the electrical signal at each intersection is used to control the pixel to be in a bright state or a dark state, when the bright state voltage and the selection state voltage are applied to the pixel, the pixel is in a bright state, and when the dark state is applied to the pixel When the state voltage is equal to the selected state voltage, the pixel is in a dark state.

In some embodiments, the first direction is perpendicular to the second direction.

In some embodiments, the cholesteric liquid crystal display device uses a dynamic driving method to drive voltage.

In some embodiments, a ratio of the second voltage difference to the first voltage difference ranges from 0.7 to 0.8.

In some embodiments, the cholesteric liquid crystal display device is driven by passive driving voltage.

In some embodiments, a ratio of the second voltage difference to the first voltage difference ranges from 0.8 to 0.95.

In order to achieve at least one of the above advantages or other advantages, another embodiment of the present invention further provides a cholesteric liquid crystal display device. The cholesteric liquid crystal display device includes a plurality of writing terminals and a plurality of scanning terminals.

The plurality of writing terminals are arranged along a first direction, and have a bright state voltage and a dark state voltage. The plurality of scanning terminals are arranged along a second direction, and have a selected state voltage and a non-selected state voltage. The writing terminals and the scanning terminals intersect each other to form a plurality of intersections, and the electrical signal at each intersection is used to control a pixel. Wherein, the absolute value of the non-selected state voltage is greater than 1/2 of the sum of the absolute value of the bright state voltage and the absolute value of the dark state voltage.

In some embodiments, the absolute value of the non-selected state voltage is smaller than the absolute value of the dark state voltage.

In some embodiments, the absolute value of the dark-state voltage is greater than the absolute value of the bright-state voltage.

Therefore, using the cholesteric liquid crystal display device provided by the present invention, by setting the second voltage difference smaller than the first voltage difference, Crosstalk can be avoided on the cholesteric liquid crystal display device, and unselected pixels can also be prevented from displaying a display state. The display performance of the cholesteric liquid crystal display device is guaranteed.

In addition, by setting the absolute value of the non-selected state voltage to be greater than 1/2 of the sum of the absolute value of the bright state voltage and the absolute value of the dark state voltage, Crosstalk can be avoided on the cholesteric liquid crystal display device, and the non-selected state can be avoided. The pixels in the cholesteric liquid crystal display device also exhibit a display state, which ensures the display performance of the cholesteric liquid crystal display device.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the preferred embodiments are specifically cited below, together with the drawings, and detailed descriptions are as follows.

Specific structural and functional details disclosed herein are representative only and are for purposes of describing example embodiments of the invention. This invention may, however, be embodied in many alternative forms and should not be construed as limited to only the embodiments set forth herein.

In describing the present invention, it is to be understood that the terms "central", "lateral", "upper", "lower", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device or positional relationship. The components must have a particular orientation, be constructed, and operate in a particular orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. Additionally, the term "comprise" and any variations thereof, are intended to cover a non-exclusive inclusion.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the exemplary embodiments. As used herein, the singular forms "a", "an" and "an" are also intended to include the plural unless the context clearly dictates otherwise. It should also be understood that the term "comprises" and/or "comprises" as used herein specifies the presence of stated features, integers, steps, operations, units and/or components and does not exclude the presence or addition of one or more Other features, integers, steps, operations, units, components and/or combinations thereof.

Please refer to FIGS. 1 and 2 . FIG. 1 is a schematic diagram of the cholesteric liquid crystal display device 10 of the present invention, and FIG. 2 is a schematic diagram of the operation of the cholesteric liquid crystal display device 10 shown in FIG. 1 . In order to achieve at least one of the above advantages or other advantages, an embodiment of the present invention provides a cholesteric liquid crystal display device 10 . As shown in the figure, the cholesteric liquid crystal display device 10 includes a plurality of writing terminals 12 and a plurality of scanning terminals 14 .

The plurality of write-in terminals 12 are arranged along the first direction X, and have bright-state voltage W and dark-state voltage B. In FIG. The directions of the arrows and the arrows indicate that the bright state voltage W is applied to the write terminal 12 . The plurality of scan ends 14 are arranged along the second direction Z, and have a selected state voltage Y and a non-selected state voltage N. In FIG. The direction of the arrow indicates that the scanning terminal 14 is applied with the selected state voltage Y.

The writing terminals 12 and the scanning terminals 14 intersect each other to form a plurality of intersections, and the electrical signal at each intersection is used to control the pixels. Specifically, as shown in the figure, when the bright state voltage W and the selected state voltage Y are applied to the pixel A1 at the same time, the pixel A1 is in a bright state; when the dark state voltage B and the selected state voltage Y are applied to the pixel A2 at the same time, The pixel A2 is in a dark state; when the bright state voltage W and the non-selection state voltage N are applied to the pixel A3 at the same time, the pixel A3 will not change, and the original color will be maintained; when the dark state voltage B and the non-selection state voltage When the state voltage is N, the pixel A4 will not change, and will maintain the original color. In other words, the electrical signal at each intersection is used to control the pixel to be in a bright state or a dark state. When the bright state voltage W and the selection state voltage Y are applied to the pixel, the pixel is in a bright state, and when the dark state voltage is applied to the pixel When B and the selected state voltage Y, the pixel is in a dark state.

The bright state and dark state refer to the brightness of the pixel. For example, dark colors such as dark red and dark green belong to the dark state of the pixel, and bright colors such as bright red and bright green belong to the bright state of the pixel. In one embodiment, the first direction X is perpendicular to the second direction Z to form intersections arranged in a matrix, which is convenient for applying voltage and controlling pixels.

As shown in the figure, the absolute value of the difference between the bright state voltage W and the non-selected state voltage N in the same time period is defined as the first voltage difference V1, and the dark state voltage B and the non-selected state voltage N in the same time period The absolute value of the difference is defined as the second voltage difference V2. By setting the second voltage difference V2 smaller than the first voltage difference V1, the occurrence of Crosstalk on the cholesteric liquid crystal display device 10 can be effectively reduced, ensuring that the cholesteric liquid crystal display The display performance of the device 10. For example, the forward voltage VP1 of the bright state voltage W=10V, the forward voltage VP2 of the non-selected state voltage N=15V, and the forward voltage VP3 of the dark state voltage B=18V, then the first voltage difference V1=|VP1 -VP2|=5V, the second voltage difference V2=|VP3-VP2|=3V, that is, V2<V1, effectively reducing the occurrence of Crosstalk on the cholesteric liquid crystal display device 10 .

In addition, the absolute value of the non-selected state voltage N is greater than 1/2 of the sum of the absolute value of the bright state voltage W and the absolute value of the dark state voltage B to ensure that the second voltage difference is smaller than the first voltage difference, Crosstalk on the cholesteric liquid crystal display device 10 is avoided. For example, if the forward voltage VP1 of the bright state voltage W is 10V, and the forward voltage VP3 of the dark state voltage B is 18V, then the forward voltage VP2 of the non-selected state voltage N should be greater than 14V. Assuming VP2=15V, the first The first voltage difference V1=|VP1-VP2|=5V, the second voltage difference V2=|VP3-VP2|=3V, satisfying V2<V1, can effectively reduce the occurrence of Crosstalk on the cholesteric liquid crystal display device 10 . It is supplemented that, in this manner, the absolute value of the non-selected state voltage N should be smaller than the absolute value of the dark state voltage B; the absolute value of the dark state voltage B should be greater than the absolute value of the bright state voltage W.

Further, when the cholesteric liquid crystal display device 10 uses a dynamic driving method to drive the voltage, such as DDS (Dynamic Driving Scheme) dynamic driving method, it is preferable to control the ratio range of the second voltage difference V2 to the first voltage difference V1 within 0.7~0.8 . When the cholesteric liquid crystal display device 10 is driven by a dynamic driving method, such as a PWM (Pulse Width Modulation) driving method of PM (Passive Matrix), it is preferable to control the ratio range of the second voltage difference V2 to the first voltage difference V1 within 0.8~0.95.

In summary, using the cholesteric liquid crystal display device 10 provided by the present invention, by setting the second voltage difference V2 smaller than the first voltage difference V1, Crosstalk can be avoided on the cholesteric liquid crystal display device 10, and unselected The pixels also exhibit a display state, which ensures the display performance of the cholesteric liquid crystal display device 10 . In addition, by setting the absolute value of the non-selected state voltage N greater than 1/2 of the sum of the absolute value of the bright state voltage W and the absolute value of the dark state voltage B, Crosstalk on the cholesteric liquid crystal display device 10 can be avoided. The display performance of the cholesteric liquid crystal display device 10 is guaranteed by preventing the unselected pixels from changing the display state.

Through the above detailed description of the preferred embodiments, it is hoped that the characteristics and spirit of the present invention can be described more clearly, and the scope of the present invention is not limited by the preferred embodiments disclosed above. On the contrary, the intention is to cover various changes and equivalent arrangements within the scope of the claimed patent scope of the present invention.

10: Cholesterol liquid crystal display device 12: Write terminal 14: Scanning end A1, A2, A3, A4: pixels B: dark state voltage W: bright state voltage N: Non-selection state voltage Y: select state voltage X: first direction Z: the second direction V1: first voltage difference V2: second voltage difference

The included drawings are used to provide a further understanding of the embodiments of the present application, which constitute a part of the specification, are used to illustrate the implementation of the present application, and explain the principle of the present application together with the text description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative efforts. In the schema: [ Fig. 1 ] is a schematic diagram of a cholesteric liquid crystal display device of the present invention. [ FIG. 2 ] is a schematic diagram of the operation of the cholesteric liquid crystal display device shown in FIG. 1 .

10: Cholesterol liquid crystal display device

12: Write terminal

14: Scanning end

A1, A2, A3, A4: pixels

B: dark state voltage

W: bright state voltage

N: Non-selection state voltage

Y: select state voltage

X: first direction

Z: the second direction

Claims (10)

A cholesteric liquid crystal display device, comprising: a plurality of writing terminals arranged along a first direction and having a bright state voltage and a dark state voltage; a plurality of scanning terminals arranged along a second direction and having a selection state voltage and a dark state voltage A non-selected state voltage, the writing terminals and the scanning terminals cross each other to form a plurality of crossing points, and the electrical signal at each crossing point is used to control a pixel; wherein, the bright state voltage and the The absolute value of the difference of the non-selected state voltage is defined as the first voltage difference, and the absolute value of the difference between the dark state voltage and the non-selected state voltage in the same time period is defined as the second voltage difference, and the second voltage difference is less than The first voltage difference; wherein, the writing end only applies the bright state voltage or the dark state voltage to the pixel at the same time, and the scanning end only applies the selected state voltage or the non-selected state voltage to the pixel at the same time state voltage. The cholesteric liquid crystal display device as claimed in claim 1, wherein the electrical signal at each cross point is used to control the pixel to be in a bright state or a dark state, and when the bright state voltage and the selection state voltage are applied to the pixel, the pixel appears bright state, when the dark state voltage and the selection state voltage are applied to the pixel, the pixel is in a dark state. The cholesteric liquid crystal display device as claimed in claim 1, wherein the first direction is perpendicular to the second direction. The cholesteric liquid crystal display device as claimed in Claim 1, wherein the cholesteric liquid crystal display device uses a dynamic driving method to drive voltage. The cholesteric liquid crystal display device according to claim 4, wherein the ratio of the second voltage difference to the first voltage difference ranges from 0.7 to 0.8. The cholesteric liquid crystal display device as claimed in Claim 1, wherein the cholesteric liquid crystal display device uses passive driving mode to drive voltage. The cholesteric liquid crystal display device according to claim 6, wherein the ratio of the second voltage difference to the first voltage difference ranges from 0.8 to 0.95. A cholesteric liquid crystal display device, comprising: a plurality of writing terminals arranged along a first direction and having a bright state voltage and a dark state voltage; a plurality of scanning terminals arranged along a second direction and having a selection state voltage and a dark state voltage A non-selected state voltage, the writing terminals and the scanning terminals cross each other to form a plurality of crossing points, and the electrical signal at each crossing point is used to control a pixel; wherein, the absolute value of the non-selecting state voltage is greater than the bright 1/2 of the sum of the absolute value of the absolute value of the state voltage and the absolute value of the dark state voltage; wherein, the writing terminal only applies the bright state voltage or the dark state voltage to the pixel at the same time, and the scanning terminal applies the Only the selected state voltage or the non-selected state voltage is applied to the pixel at the same time. The cholesteric liquid crystal display device as claimed in claim 8, wherein the absolute value of the non-selected state voltage is smaller than the absolute value of the dark state voltage. The cholesteric liquid crystal display device as claimed in Claim 8, wherein the absolute value of the dark state voltage is greater than the absolute value of the bright state voltage.

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