Cholesteric liquid crystal display and driving method thereof
By adding ghosting elimination voltage to the scanning sequence of the cholesterol liquid crystal display, the image quality problem caused by scanning sequence signal interference is solved, and a more stable imaging effect is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- IRIS OPTRONICS INC
- Filing Date
- 2023-05-17
- Publication Date
- 2026-05-29
AI Technical Summary
In existing cholesterol-based liquid crystal displays, the selection stage signal of the (N+1)th scan sequence is directly connected to the selection stage signal of the Nth scan sequence, which interferes with the voltage of the evolution stage of the Nth scan sequence and affects the image quality.
Ghosting elimination voltages are applied during the selection phases of the Nth and Mth scan sequences for a duration of T, in order to eliminate the presence of the image from the Mth scan sequence at the image position of the Nth scan sequence.
Effectively eliminates ghosting and improves the image quality of cholesterol-free LCD monitors.
Smart Images
Figure CN119007671B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of liquid crystal display technology, and in particular to a cholesterol liquid crystal display and its driving method. Background Technology
[0002] Cholesterol liquid crystal displays are a type of liquid crystal display. Cholesterol liquid crystals have bistable characteristics, meaning that they have two stable states when no external force is applied. This is the biggest difference between them and the commonly used TFT liquid crystal displays and OLED displays.
[0003] Cholesterol liquid crystal molecules exhibit two stable states, thus possessing bistable characteristics. This means that cholesterol liquid crystals can maintain their original molecular arrangement without requiring external energy. When a voltage is applied, the arrangement of cholesterol liquid crystal molecules can be controlled to switch between the two stable states: a focal conical arrangement and a planar arrangement.
[0004] Cholesterol liquid crystal displays (LCDs) are typically driven using the DDS (Dynamic Driving Scheme). DDS is a three-phase driving method that utilizes the relatively fast transition speed of cholesterol liquid crystals between the homeotropic and transient planar states and the hysteresis between the focal-conic and homeotropic states. Figure 1 As shown, the phases are preparation, selection, evolution, and non-selection. The preparation phase converts the cholesteric liquid crystal into a vertically aligned state. The selection phase determines whether the selected state is a focal-conic state or a planar state. To transition to a planar state, the vertical alignment is maintained; to transition to a focal-conic state, a transient planar state is maintained. The evolution phase utilizes the hysteresis between the vertical alignment and focal-conic states to achieve rapid conversion to either the planar or focal-conic state. The remaining time is spent in the non-selection phase.
[0005] like Figure 2 As shown, Figure 2 The horizontal axis represents time, and from top to bottom, they represent the Column, the Nth scan timing sequence, the (N+1)th scan timing sequence, and the (N+2)th scan timing sequence, respectively. Figure 2 The fluctuation patterns at each stage and Figure 1 The stages shown are the same. The inventors discovered that, currently, because the selection stage signal of the (N+1)th scan sequence is directly followed by the selection stage signal of the Nth scan sequence, it interferes with the evolution stage voltage of the Nth scan sequence during imaging, causing the image of the N+1th scan sequence to appear in the image presented by the Nth scan sequence, which seriously affects the image presentation quality of the cholesteric liquid crystal display.
[0006] Therefore, the main objective of this invention is to provide a cholesterol liquid crystal display and its driving method to solve the above-mentioned problems.
[0007] It should be noted that the information disclosed in this background section is intended only to enhance the understanding of the overall background of the present invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention
[0008] The purpose of this invention is to provide a cholesterol liquid crystal display and its driving method. By applying a ghosting elimination voltage for a time T during the selection stages of the Nth and Mth scan sequences, the image of the Mth scan sequence is eliminated from being displayed at the image position of the Nth scan sequence. This allows the liquid crystal of the Nth scan sequence to stabilize before the imaging of the Mth scan sequence begins.
[0009] To achieve at least one or more of the aforementioned advantages, an embodiment of the present invention provides a driving method for a cholesteric liquid crystal display, comprising: using a liquid crystal driving unit to output a row driving voltage to a corresponding row circuit structure; the liquid crystal driving unit outputs a column driving voltage and sequentially outputs it to a corresponding column circuit structure in a scanning manner, wherein scanning a column circuit structure requires a scanning sequence; when the Nth scanning sequence of a pixel is started to present an image, a ghosting elimination voltage is applied to eliminate the image of the Mth scanning sequence from being presented at the image position of the Nth scanning sequence, wherein M = N + 1, and the application time of the ghosting elimination voltage is T.
[0010] In some embodiments, the scan timing sequence includes a preparation phase, a selection phase, an evolution phase, and a non-selection phase, and a ghost elimination voltage is applied during the selection phase of the Nth scan timing sequence.
[0011] In some embodiments, the column drive voltage has a preparation phase, a selection phase, an evolution phase and a non-selection phase according to the scan timing sequence, the Nth scan timing sequence and the Mth scan timing sequence have a selection phase of the same duration, and the application time T is at least 10% of the duration of the selection phase.
[0012] In some embodiments, the application time T is 100% of the duration of the selection phase.
[0013] In some embodiments, the pixel rendering is updated by scanning the timing in a dynamically driven manner.
[0014] In some embodiments, the number of pixels is multiple, and the multiple pixels are arranged in a passive matrix.
[0015] To achieve at least one or more of the aforementioned advantages, an embodiment of the present invention also provides a cholesteric liquid crystal display, comprising a liquid crystal display panel and a liquid crystal driving unit. The liquid crystal display panel has a plurality of pixels. The liquid crystal driving unit is coupled to the liquid crystal display panel, and drives the pixels on the liquid crystal display panel to display an image. The liquid crystal driving unit outputs a row driving voltage to the corresponding row circuit structure, and sequentially outputs a column driving voltage to the corresponding column circuit structure in a scanning manner. A scanning sequence is required when scanning a column circuit structure. Specifically, the liquid crystal driving unit first initiates the Nth scanning sequence of the pixel to display the image. Subsequently, the liquid crystal driving unit applies a ghosting elimination voltage to eliminate the image of the Mth scanning sequence from being displayed at the image position of the Nth scanning sequence, where M = N + 1, and the application time of the ghosting elimination voltage is T.
[0016] In some embodiments, the column drive voltage has a preparation phase, a selection phase, an evolution phase and a non-selection phase according to the scan timing sequence, wherein the Nth scan timing sequence and the Mth scan timing sequence have a selection phase of the same duration, and the application time T is at least 10% of the duration of the selection phase.
[0017] In some embodiments, the application time T is 100% of the duration of the selection phase.
[0018] In some embodiments, the liquid crystal driving unit updates the display image of the pixels by scanning the timing in a dynamic driving manner.
[0019] In some embodiments, the plurality of pixels are arranged in a passive matrix.
[0020] Therefore, by utilizing the cholesteric liquid crystal display and its driving method provided by the present invention, by applying a ghosting elimination voltage for a duration of T during the selection stages of the Nth and Mth scan sequences, the image of the Mth scan sequence is eliminated from being displayed at the image position of the Nth scan sequence. This allows the liquid crystal of the Nth scan sequence to be displayed more stably before the imaging of the Mth scan sequence begins, effectively improving the ghosting phenomenon on the cholesteric liquid crystal display and enhancing the imaging quality of the cholesteric liquid crystal display.
[0021] Other features and beneficial effects of the invention will be set forth in the following description, and some of these features and beneficial effects may be apparent from the description or learned by practicing the invention. The objects of the invention and other beneficial effects may be realized and obtained through the structures specifically pointed out in the description and other contents. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 This is a schematic diagram of the four stages of a cholesterol liquid crystal display in DDS mode;
[0024] Figure 2 This is a schematic diagram of the scanning timing during the operation of a cholesterol liquid crystal display.
[0025] Figure 3 This is a schematic diagram of the scanning timing of a cholesterol liquid crystal display after the selection phase, when the cholesterol liquid crystal display driving method of the present invention is used during operation.
[0026] Figure 4 This is a schematic diagram of the scanning timing of a cholesterol liquid crystal display (CLCD) operating after using the CLCD driving method of the present invention, prior to the selection phase. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0028] In the description of this invention, it should be understood that the terms "center," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Additionally, the term "comprising" and any variations thereof mean "at least comprising."
[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integrally formed connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0030] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.
[0031] Combination Figure 1 , Figure 2 Please see Figure 3 , Figure 3 This is a schematic diagram of the scanning timing of a cholesterol liquid crystal display (CLCD) operating using the CLCD driving method of the present invention. Figure 3 The horizontal axis represents time, and from top to bottom, they represent the Column, the Nth scan timing sequence, the (N+1)th scan timing sequence, and the (N+2)th scan timing sequence, respectively. Figure 2 The fluctuation patterns at each stage and Figure 1 The stages shown are the same.
[0032] To achieve at least one or more of the aforementioned advantages, an embodiment of the present invention provides a driving method for a cholesterol liquid crystal display, the driving method comprising the following steps:
[0033] S1. Use a liquid crystal driving unit to output a row driving voltage to the corresponding row circuit structure, and output a column driving voltage to the corresponding column circuit structure in a scanning manner. A scanning timing is required when scanning a column circuit structure.
[0034] S2, Start the Nth scan sequence of the pixel to display the image;
[0035] S3. Apply a ghosting elimination voltage for a time of T to eliminate the image of the Mth scan sequence from appearing at the image position of the Nth scan sequence, where M = N + 1.
[0036] by Figure 3 For example, the horizontal axis represents time, and from top to bottom, they represent the Column, the Nth scan timing sequence, the (N+1)th scan timing sequence, and the (N+2)th scan timing sequence. Figure 2 The fluctuation patterns at each stage and Figure 1 The stages shown are the same. The (N+1)th scan timing sequence is the Mth scan timing sequence relative to the Nth scan timing sequence, and the (N+2)th scan timing sequence is the Mth scan timing sequence relative to the (N+1)th scan timing sequence. As can be seen from the figure, both the Nth and Mth scan timing sequence display screens have selection stages of the same duration. The increased ghosting elimination voltage is applied for a time T, where T is 100% of the selection stage duration. Figure 3 The areas circled in each scan sequence represent the ghosting removal time, which can be compared. Figure 2 and Figure 3 (To understand this). By increasing the ghosting elimination voltage and applying it for a time T, the LCD in the Nth scan sequence is made relatively stable before the imaging of the Mth scan sequence begins. In other words, the voltage of the evolution stage circled in the Nth scan sequence is not interfered with by the selection stage of the next scan sequence (N+1th scan sequence) (even though the data of the N+1th scan sequence will no longer affect the imaging quality of the Nth scan sequence). Since the imaging of the evolution stage is the most critical, this method can effectively improve the ghosting phenomenon on cholesteric LCDs and enhance the imaging quality of cholesteric LCDs.
[0037] In some embodiments, the increased ghosting elimination voltage is applied for a time T that is at least 10% of the duration of the selection phase. Preferably, the application time T is 100% of the duration of the selection phase. Preferably, the application time T is at most 300% of the duration of the selection phase. The increased ghosting elimination voltage can range from the voltage of the evolution phase to the preparation phase.
[0038] In some embodiments, the rendering of pixels is updated using a dynamically driven scanning sequence (DDS).
[0039] In some embodiments, the number of pixels is multiple, and the multiple pixels form a passive matrix.
[0040] Furthermore, the ghosting elimination voltage can be inserted before or after the selection phase. Both insertion points can effectively improve the ghosting phenomenon on cholesteric LCDs and enhance their image quality. For example... Figure 4 As shown, the ghosting elimination voltage is a scanning timing diagram of the cholesterol liquid crystal display during operation when the selection stage is inserted before startup.
[0041] An embodiment of the present invention also proposes a cholesteric liquid crystal display, comprising a liquid crystal display panel and a liquid crystal driving unit. The liquid crystal display panel has a plurality of pixels. The liquid crystal driving unit is coupled to the liquid crystal display panel, and drives the pixels on the liquid crystal display panel to display an image. The liquid crystal driving unit outputs a row driving voltage to the corresponding row circuit structure, and sequentially outputs a column driving voltage to the corresponding column circuit structure in a scanning manner. A scanning sequence is required when scanning a column circuit structure. Specifically, the liquid crystal driving unit first initiates the Nth scanning sequence of the pixel to display the image. Subsequently, the liquid crystal driving unit applies a ghosting elimination voltage to eliminate the image of the Mth scanning sequence from being displayed at the image position of the Nth scanning sequence, where M = N + 1, and the application time of the ghosting elimination voltage is T.
[0042] In some embodiments, the column drive voltage has a preparation phase, a selection phase, an evolution phase and a non-selection phase according to the scan timing sequence, wherein the Nth scan timing sequence and the Mth scan timing sequence have a selection phase of the same duration, and the application time T is at least 10% of the duration of the selection phase.
[0043] In some embodiments, the increased ghosting elimination voltage is applied for a time T equal to 100% of the duration of the selection phase.
[0044] In some embodiments, the liquid crystal driving unit updates the pixel display by scanning the timing sequence in a dynamic driving manner.
[0045] In some embodiments, the plurality of pixels are arranged in a passive matrix.
[0046] In summary, by utilizing the cholesteric liquid crystal display and its driving method provided by this invention, and by applying a ghosting elimination voltage for a duration of T during the Nth and Mth selection stages of the scanning sequence, the image of the Mth scanning sequence is eliminated from appearing at the image position of the Nth scanning sequence. This allows the liquid crystal of the Nth scanning sequence to stabilize before the imaging of the Mth scanning sequence begins, effectively improving the ghosting phenomenon on the cholesteric liquid crystal display and enhancing its imaging quality.
[0047] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.
[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A driving method for a cholesterol liquid crystal display, characterized in that: The driving method includes: A liquid crystal driving unit outputs a row of driving voltages to the corresponding row of circuit structures. The liquid crystal driving unit outputs a column of driving voltages and sequentially outputs them to the corresponding column of circuit structures in a scanning manner. Scanning a column of circuit structures requires a scanning timing sequence. When the image is presented in the Nth scan sequence of the starting pixel, a ghosting elimination voltage is applied to eliminate the image of the Mth scan sequence from being presented at the image position of the Nth scan sequence, where M=N+1, and the application time of the ghosting elimination voltage is T; The scanning timing sequence includes a preparation phase, a selection phase, an evolution phase, and a non-selection phase. The ghost elimination voltage is applied during the selection phase of the Nth scanning timing sequence, and the insertion point of the ghost elimination voltage is before or after the selection phase.
2. The driving method for a cholesterol liquid crystal display according to claim 1, characterized in that: The Nth scan timing sequence and the Mth scan timing sequence have selection phases of the same duration, and the application time T is at least 10% of the duration of the selection phase.
3. The driving method for a cholesterol liquid crystal display according to claim 1, characterized in that: The application time T is 100% of the duration of the selection phase.
4. The driving method for a cholesterol liquid crystal display according to claim 1, characterized in that: The pixel rendering is updated by scanning the timing in a dynamic driving manner.
5. The driving method for a cholesterol liquid crystal display according to claim 1, characterized in that: The number of pixels is multiple, and the multiple pixels form a passive matrix.
6. A cholesterol liquid crystal display, characterized in that: The cholesterol liquid crystal display includes: A liquid crystal display panel having a plurality of pixels; A liquid crystal driving unit is coupled to the liquid crystal display panel. The liquid crystal driving unit drives the pixels on the liquid crystal display panel to display an image. The liquid crystal driving unit outputs a row of driving voltage to the corresponding row circuit structure and sequentially outputs a column of driving voltage to the corresponding column circuit structure in a scanning manner. Scanning a column circuit structure requires a scanning timing sequence. The liquid crystal driving unit first starts the Nth scan sequence of the pixel to present the image. During the selection phase of the Nth scan sequence, a ghosting elimination voltage is applied to the liquid crystal driving unit to eliminate the image of the Mth scan sequence from being presented at the image position of the Nth scan sequence. Here, M=N+1, and the application time of the ghosting elimination voltage is T. The scan timing sequence includes a preparation phase, a selection phase, an evolution phase, and a non-selection phase. A ghost elimination voltage is applied during the selection phase of the Nth scan timing sequence, and the insertion point of the ghost elimination voltage is before or after the selection phase.
7. The cholesterol liquid crystal display according to claim 6, characterized in that: The Nth scan timing sequence and the Mth scan timing sequence have selection phases of the same duration, and the application time T is at least 10% of the duration of the selection phase.
8. The cholesterol liquid crystal display according to claim 6, characterized in that: The application time T is 100% of the duration of the selection phase.
9. The cholesterol liquid crystal display according to claim 6, characterized in that: The liquid crystal driving unit updates the display image of the pixels by scanning the timing in a dynamic driving manner.
10. The cholesterol liquid crystal display according to claim 6, characterized in that: The plurality of pixels form a passive matrix.