Cholesteric liquid crystal display device of mixed driving type, microprocessor and mixed driving method

Abstract

To provide a hybrid-driven cholesteric liquid crystal display, a micro processor, and a method for hybrid driving.SOLUTION: A cholesteric liquid crystal display 30 comprises a display panel and a microprocessor 34. A grayscale threshold value is set for a screen displayed on the display panel 32. The micro microprocessor 34 first changes a numerical value exceeding the grayscale threshold value to a grayscale value displayed with a bright state color, and then displays the screen by driving the display panel 32 in a DDS driving mode. Further, the microprocessor 34 drives the display panel 32 in a PWM driving mode. This can greatly improve the color level and contrast display effect of the screen.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a cholesteric liquid crystal display device of a mixed driving mode, a microprocessor, and a mixed driving method, and more particularly to a cholesteric liquid crystal display device that displays a screen by a mixed driving mode of a DDS driving mode and a PWM driving mode, a microprocessor, and a mixed driving method. [Background technology]

[0002] Cholesteric Liquid Crystal Displays (Ch-LCDs) are bi-stable and can maintain the displayed content without consuming power, so they are often used in products such as temperature sensor displays, e-books, e-paper, and e-whiteboards. Summary of the Invention [Problem to be solved by the invention]

[0003] The screen display portion of a cholesteric liquid crystal display device is called a display panel, which includes a plurality of display units that display a common screen, and which displays the screen by driving the display panel in a DDS driving mode and a PWM driving mode.

[0004] The characteristics of the PWM driving mode are poor contrast display effect and good gradation display effect. This is because the reflection effect is poor when displaying the color in the dark state, the general reflectance is 6%. The gray scale depth of the PWM driving mode is high, and it is generally represented by 16 gray scales. The characteristics of the DDS driving mode are good contrast display effect and not ideal gradation display effect. This is because the reflection rate is low when displaying the color in the dark state, and it is generally represented by only 4.5%. The gray scale depth of the DDS driving mode is low, and it is generally represented by only 4 to 8 gray scales.

[0005] Referring to Figures 1 and 2, Figure 1 is a schematic diagram of a standard screen display in the prior art, and Figure 2 is a schematic diagram of a screen display in the PWM driving mode in the prior art. In order to display a screen with high gray scale, it is common to adopt the PWM driving mode as the driving mode, but the result of directly displaying the screen using the PWM driving mode with the standard screen display shown in Figure 1 as the target is as shown in Figure 2, which is a higher gray scale depth expression, but as a result, the display of the color part in the dark state is insufficiently dark, and the contrast effect of the screen is poor, as shown in the cloudy state in the right half of Figure 2.

[0006] Therefore, in order to solve the problem of difficulty in achieving both screen contrast and gradation expression in a cholesteric liquid crystal display device, the main object of the present invention is to provide a cholesteric liquid crystal display device, a microprocessor and a mixed driving method of a mixed driving type, thereby solving the above problem with an ideal technology. [Means for solving the problem]

[0007] The objective of the present invention is to provide a mixed driving cholesteric liquid crystal display device, a microprocessor and a mixed driving method, which displays a screen by mixed driving of the DDS driving mode and the PWM driving mode, thereby greatly improving the display effect of the gray scale and contrast of the screen.

[0008] The present invention relates to a mixed driving type cholesteric liquid crystal display device that improves the display effect of gray scale and contrast, and the cholesteric liquid crystal display device includes a display panel and a microprocessor.

[0009] The display panel includes a plurality of display units displaying a common screen, and the screen is set to a predetermined grayscale depth so that each display unit has a corresponding grayscale value, and the grayscale depth requires a preset threshold value.

[0010] The microprocessor may be a timing controller (TCON). The microprocessor first prepares grayscale values ​​to be displayed on multiple display units of the screen, changes the values ​​exceeding the grayscale threshold to grayscale values ​​to be displayed in bright colors, then drives the display panel in the DDS driving mode to display the screen, and further drives the display panel in the PWM driving mode based on the range of grayscale depth to display the screen. This can greatly improve the display effect of the gradation and contrast of the screen.

[0011] As in the above-mentioned cholesteric LCD device, the predetermined grayscale depth range of the screen is a grayscale value of 0 to 255, the grayscale threshold value can be set to 16, and the grayscale value of the light state color can be set to 240 or more.

[0012] Furthermore, the display unit of the screen may have three primary colors R, G, and B, each with a corresponding grayscale value.

[0013] The present invention is not only a cholesteric liquid crystal display device, but also a microprocessor for a mixed driving method used in the cholesteric liquid crystal display device, the microprocessor can improve the display effect of gray scale and contrast of the screen of the cholesteric liquid crystal display device, the screen has a predetermined gray scale depth so that each display unit has a corresponding gray scale value, and the microprocessor includes a DDS driving module and a PWM driving module.

[0014] A grayscale threshold value needs to be preset for the grayscale values ​​in the grayscale depth range. First, the DDS driving module changes the grayscale values ​​that exceed the grayscale threshold value among the grayscale values ​​to be displayed by the multiple display units of the screen to grayscale values ​​that are displayed in a bright state color, and then drives the display panel in a DDS driving mode to display the screen.

[0015] After the DDS driving module changes the display units on the screen that exceed the grayscale value threshold to a bright color display, the PWM driving module then drives the display panel in PWM driving mode according to the grayscale depth range to display the screen. After being driven by the DDS driving module, when driven by the PWM driving module, the gray scale and contrast of the displayed screen are improved, and the overall display effect is improved.

[0016] Like the microprocessor described above, the microprocessor may also be a Timing Controller (TCON).

[0017] To further explain, as in the microprocessor described above, the predetermined greyscale depth range of the screen is a greyscale value of 0 to 255, the greyscale threshold value can be set to 16, and the greyscale value of the light state colour can be set to 240 or greater.

[0018] The present invention is not only a mixed driving cholesteric liquid crystal display device and a microprocessor, but also a mixed driving method. The mixed driving method is for driving a cholesteric liquid crystal display device to improve the display effect of gray scale and contrast of a screen of a display panel, the screen has a predetermined gray scale depth, and a threshold value needs to be preset for the gray scale depth, so that each display unit has a corresponding gray scale value. The mixed driving method includes the following steps:

[0019] First, among the gray scale values ​​to be displayed by a plurality of display units of a screen, values ​​exceeding the gray scale threshold value are changed to gray scale values ​​to be displayed in a bright state color.

[0020] Next, the display panel is driven in the DDS drive mode to display the screen.

[0021] Furthermore, the display panel is driven in a PWM driving mode based on the range of gray scale depth to display the screen.

[0022] In this way, after the bright state color correction is performed, the gray scale and contrast of the screen displayed first in the DDS driving mode and then in the PWM driving mode are greatly improved, and the display effect of the entire screen is improved.

[0023] Additionally, as in the above-mentioned mixed driving method, the predetermined grayscale depth range of the screen is a grayscale value of 0 to 255, the grayscale threshold value can be set to 16, and the grayscale value of the light state color can be set to 240 or more.

[0024] To further explain, the driving time ratio between the DDS driving mode and the PWM driving mode is preferably 1:4, so that the display effect of the screen is ideal.

[0025] Therefore, the cholesteric liquid crystal display device, microprocessor and mixed driving method of the present invention use a microprocessor such as a timing controller to control the display panel to display a screen, preset the gray scale threshold, sequentially mix and drive the DDS driving mode and the PWM driving mode, and perform color correction in the bright state after driving in the DDS driving mode, which can greatly improve the display effect of the gray scale and contrast of the screen.

[0026] The advantages and spirit of the present invention can be further understood from the following detailed description and drawings. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a schematic diagram of a standard screen display in the prior art. [Diagram 2] FIG. 2 is a schematic diagram of a screen display in a PWM driving mode in the prior art. [Diagram 3] 1 is a schematic diagram of a functional element of a mixed driving cholesteric liquid crystal display device of the present invention; [Figure 4A]FIG. 2 is a schematic diagram showing a display screen when driven in the DDS driving mode of the present invention. [Figure 4B] FIG. 2 is a schematic diagram of the present invention in which the DDS driving mode is followed by the PWM driving mode to display a screen. [Diagram 5] 1 is a schematic diagram of the functional modules of the mixed drive microprocessor of the present invention; [Figure 6] 2 is a flow chart of the mixed driving method of the present invention. [Figure 7] FIG. 4 is a comparison diagram of the screen display effect of different driving time ratios of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The present invention relates to a mixed driving cholesteric liquid crystal display device, a microprocessor and a mixed driving method, and the display effect of gray scale and contrast of the screen can be greatly improved by sequentially mixing and driving the DDS driving mode and the PWM driving mode. Please refer to Fig. 3. Fig. 3 is a schematic diagram of the functional elements of the mixed driving cholesteric liquid crystal display device of the present invention. The present invention relates to a mixed driving cholesteric liquid crystal display device 30 that improves the display effect of gray scale and contrast, and the cholesteric liquid crystal display device 30 includes a display panel 32 and a microprocessor 34.

[0029] The display panel 32 includes a plurality of display units (not shown) displaying a common screen, the screen has a predetermined grayscale depth, and a specific threshold needs to be set within the grayscale depth range, so that each display unit has a corresponding grayscale value. The predetermined grayscale depth range of the screen is a grayscale value of 0 to 255, and the grayscale value range of 0 to 255 is a general definition of the grayscale depth range, where the higher the grayscale value, the brighter the display, and when the grayscale value is 255, it is almost bright white, and when the grayscale value is lower, it is almost dark black. According to the results of repeated experiments by the inventor, the grayscale threshold value of 16 can provide an ideal display effect, and the test results and evidence are shown in the following diagram.

[0030] When the display panel 32 starts to be driven to display a screen, the microprocessor 34 first changes the grayscale values ​​that exceed the grayscale threshold value among the grayscale values ​​to be displayed by the multiple display units of the screen to grayscale values ​​that are displayed in a bright state color, and then drives the display panel 32 in the DDS driving mode to display the screen. The grayscale value of the bright state color can be 240 or more, or directly adopt 255, which means that it is displayed in almost bright white color.

[0031] Next, the microprocessor 34 drives the display panel based on the range of grayscale depth in the PWM driving mode to display the screen. That is, it displays a specific grayscale value to be displayed within the grayscale depth range of 0 to 255. In this way, the numerical value exceeding the grayscale threshold is changed to a grayscale value that is displayed in a bright state color, and then the screen is displayed in the DDS driving mode, and then the screen is displayed in the PWM driving mode, thereby greatly improving the display effect of the gradation and contrast of the screen. In addition, the above-mentioned microprocessor 34 can adopt a timing controller (Timing Controller, TCON).

[0032] Furthermore, like the above-mentioned cholesteric liquid crystal display device 30, the display unit of the screen may be a pure black, gray, white display mode, or a display mode of the three primary colors of R, G, B. The pure black, gray, white display mode has a grayscale depth range of 0-255, and the R, G, B primary colors display mode has a grayscale value corresponding to the grayscale depth range of 0-255 for the three primary colors of R, G, B.

[0033] Please refer to FIG. 4A according to the above. FIG. 4A is a schematic diagram of the present invention being driven in the DDS driving mode to display a screen. According to the above embodiment, the microprocessor 34 first changes the grayscale value of the display unit in the screen that exceeds the grayscale threshold value of 16 to a bright state color of 240 or more for display, or directly changes the grayscale value to a bright state color of 255 for display. As shown in FIG. 4A, the center and left halves of the screen are both changed to a bright state color of 255 for display, because their default grayscale values ​​exceed the grayscale threshold value of 16. The grayscale value of the right half of the screen is lower than the grayscale threshold value of 16, so the display state of the original grayscale value remains unchanged. Thus, the display of the entire screen is as shown in the figure.

[0034] Next, referring to FIG. 4A, we will further refer to FIG. 4B. FIG. 4B is a schematic diagram of the present invention, in which the display unit is driven in the PWM driving mode after the DDS driving mode to display a screen. The gray scale value of the display unit in the screen of FIG. 4A, which exceeds the gray scale threshold value of 16, is changed to a bright state color of 240 or more, and then the display panel 32 is driven in the PWM driving mode to display a screen. As a result, as shown in FIG. 4B, not only is the gray scale display of the screen more complete, but the contrast effect is also greatly improved, and the defects shown in FIG. 2 are avoided.

[0035] Please refer to FIG. 5. FIG. 5 is a schematic diagram of the functional modules of the mixed driving mode microprocessor of the present invention. The present invention is not only a cholesteric liquid crystal display device 30, but also a mixed driving mode microprocessor 34 for improving the display effect of gray scale and contrast of the display panel 32 in the cholesteric liquid crystal display device 30. The microprocessor 34 may adopt a timing controller. The microprocessor 34 of this embodiment further includes a DDS driving module 42 and a PWM driving module 44.

[0036] The screen has a predetermined grayscale depth so that each display unit has a corresponding grayscale value, and the grayscale depth range is, for example, a grayscale value of 0 to 255. The grayscale value range of 0 to 255 is a general definition of the grayscale depth range, where a higher grayscale value is displayed brighter, a grayscale value of 255 is almost bright white, a lower grayscale value is displayed darker, and a grayscale value of 0 is almost dark black.

[0037] First, a grayscale threshold value needs to be preset for the grayscale values ​​in the grayscale depth range, and the DDS driving module 42 changes the grayscale values ​​that exceed the grayscale threshold value among the grayscale values ​​to be displayed by the multiple display units of the screen to grayscale values ​​to be displayed in the bright state color, and then drives the display panel 32 in the DDS driving mode to display the screen. According to the results of repeated experiments by the inventor, the grayscale threshold value can be 16, and the grayscale value of the bright state color can be 240 or more, or directly 255.

[0038] After the DDS driving module 42 changes the display units in the screen that exceed the grayscale value threshold to a bright color display, the PWM driving module then drives the display panel 32 in the PWM driving mode based on the grayscale depth range to display the screen, i.e., displays a specific grayscale value to be displayed within the grayscale depth range of 0 to 255. In this way, the numerical value that exceeds the grayscale threshold is changed to a grayscale value that is displayed in a bright color, and then the screen is displayed in the DDS driving mode, and then the screen is displayed in the PWM driving mode, thereby greatly improving the display effect of the gradation and contrast of the screen.

[0039] Like the microprocessor 34 described above, the display unit of the screen may be in pure black, grey, white display mode, or in the R, G, B three primary color display mode. The pure black, grey, white display mode has a greyscale depth range of 0-255, and the R, G, B three primary color display mode has the R, G, B three primary colors each having a greyscale value corresponding to the greyscale depth range of 0-255.

[0040] Please refer to Fig. 6. Fig. 6 is a flow chart of the mixed driving method of the present invention. In addition to the above-mentioned mixed driving cholesteric liquid crystal display device 30 or the mixed driving microprocessor 34, the present invention may also be a mixed driving method for improving the display effect of grayscale and contrast of the display panel 32 in the cholesteric liquid crystal display device 30, or using the microprocessor 34 to improve the display effect of grayscale and contrast of the display panel 32.

[0041] The screen has a predetermined grayscale depth, and a specific grayscale threshold is preset for the grayscale depth, so that each display unit has a corresponding grayscale value. The mixed driving method includes the following steps.

[0042] First step (S01): First, among the grayscale values ​​to be displayed by a plurality of display units of a screen, values ​​exceeding a grayscale threshold are changed to grayscale values ​​to be displayed in a bright state color.

[0043] Second step (S02): Drive the display panel 32 in the DDS driving mode to display the screen. As mentioned above, the microprocessor 34 may be used to drive the display panel 32. Generally, the microprocessor 34 changes the grayscale value to a bright color display and resets the screen before driving the display panel 32 in the DDS driving mode, so there is no need to provide a step to reset the screen. The display result of the screen is as shown in FIG. 4A.

[0044] Third step (S03): Further, the display panel 32 is driven in the PWM driving mode based on the range of gray scale depth to display the screen, and the display result of the screen is as shown in FIG. 4B.

[0045] In this way, the numerical value exceeding the grayscale threshold is changed to a grayscale value that is displayed in a bright state color, and then the screen is displayed in DDS drive mode, and then in PWM drive mode, thereby greatly improving the display effect of the gradation and contrast of the screen.

[0046] The mixed driving method can be driven by the above-mentioned mixed driving cholesteric liquid crystal display device 30 or the above-mentioned mixed driving microprocessor 34, and the microprocessor 34 can be a timing controller.

[0047] As in the above-mentioned mixed driving method, the screen may be in a pure black, gray, white display mode, or in a display mode of the three primary colors of R, G, B. The pure black, gray, white display mode has a grayscale depth range of 0 to 255, and the R, G, B primary colors display mode has a grayscale value corresponding to the grayscale depth range of 0 to 255 for each of the three primary colors of R, G, B.

[0048] In the flow chart of the mixed driving method of the above embodiment, the predetermined grayscale depth range of the screen may be a grayscale value of 0 to 255, the grayscale value range of 0 to 255 is a general definition of a grayscale depth range, the higher the grayscale value, the brighter the display, the grayscale value of 255 is almost bright white, the lower the grayscale value, the darker the display, the grayscale value of 0 is almost dark black. According to the results of repeated experiments by the inventor, the grayscale threshold value can be 16, and the grayscale value of the bright state color can be 240 or more, or directly 255.

[0049] Please refer to Fig. 7. Fig. 7 is a comparison diagram of the screen display effect of different driving time ratios of the present invention. As in the above-mentioned mixed driving cholesteric liquid crystal display device 30, microprocessor 34, or mixed driving method, the driving time ratio of the DDS driving mode and the PWM driving mode can be 1:4, and it has been confirmed by experiment that the display effect of this driving time ratio is preferable.

[0050] The upper screen in Figure 7 is a display screen obtained when the drive time ratio between the DDS drive mode and the PWM drive mode is 1:4, and the lower screen in Figure 7 is a display screen obtained when the drive time ratio between the DDS drive mode and the PWM drive mode is 1:8. The display effect of the upper screen is obviously better than that of the lower screen, and the gradation and contrast are also more perfect.

[0051] Therefore, the mixed driving cholesteric liquid crystal display device 30, microprocessor 34 and mixed driving method provided by the present invention use the microprocessor 34, such as a timing controller, to control the display panel 32 to display a screen, preset the gray scale threshold, sequentially mix and drive the DDS driving mode and the PWM driving mode, and perform color correction in the bright state after driving in the DDS driving mode, thereby greatly improving the display effect of the gray scale and contrast of the screen.

[0052] The detailed description of the preferred embodiment above is intended to more clearly describe the features and spirit of the present invention, rather than to limit the scope of the present invention to the above-mentioned preferred embodiment, and the purpose is to include various modifications and equivalent configurations within the scope of the claims of the present invention. [Explanation of symbols]

[0053] 30: Cholesteric liquid crystal display device 32: Display panel 34: Microprocessor 42: DDS drive module 44: PWM drive module

Claims

1. A cholesteric liquid crystal display device for a mixed driving method for improving a display effect of gray scale and contrast, comprising: A display panel including a plurality of display units for displaying a common screen, the screen being preset with a predetermined range of grayscale depth so that each display unit has a corresponding unit corresponding grayscale value, and a grayscale threshold value corresponding to the range of grayscale depth is preset; a microprocessor, which prepares a plurality of display grayscale values ​​to be displayed on the plurality of display units according to a range of the grayscale depth, changes a display grayscale value among the plurality of display grayscale values ​​that exceeds the grayscale threshold value to a modified grayscale value that is displayed in a light state color, drives the display panel in a DDS drive mode to display the screen, and then drives the display panel in a PWM drive mode based on the plurality of display grayscale values ​​to display the screen, thereby improving a display effect of gradation and contrast of the screen; A cholesteric liquid crystal display device comprising:

2. 2. The cholesteric liquid crystal display device according to claim 1, wherein the display units of the screen have three primary colors of R, G and B, each having a corresponding gray scale value.

3. 2. The cholesteric liquid crystal display device according to claim 1, wherein the microprocessor is a timing controller (TCON).

4. 2. The cholesteric liquid crystal display device of claim 1, wherein the predetermined grayscale depth range of the screen is set to have the unit corresponding grayscale value of 0 to 255, the grayscale threshold value is 16, and the modified grayscale value is 240 or more.

5. A microprocessor of a mixed driving method used for improving the display effect of gray scale and contrast of one screen of one display panel screen of a cholesteric liquid crystal display device, comprising: The cholesteric liquid crystal display device includes a display panel including a plurality of display units for displaying the screen, A predetermined range of grayscale depth is preset on the screen so that each of the plurality of display units has a unit corresponding grayscale value corresponding to the display unit, and a grayscale threshold value corresponding to the range of grayscale depth is preset on the screen; The microprocessor includes: a DDS driving module that changes a display grayscale value that exceeds the grayscale threshold value among a plurality of display grayscale values ​​prepared for display on the plurality of display units according to the range of the grayscale depth to a modified grayscale value that is displayed in a light state color, and drives the display panel in a DDS driving mode to display the screen; a PWM driving module, which drives the display panel in a PWM driving mode based on the plurality of display grayscale values ​​to display the screen after the display panel is driven in the DDS driving mode by the DDS driving module, thereby improving the display effect of the gradation and contrast of the screen; A microprocessor comprising:

6. 6. The microprocessor of claim 5, wherein the microprocessor is a Timing Controller (TCON).

7. 6. The microprocessor of claim 5, wherein the predetermined grayscale depth range of the screen is set to have the unit corresponding grayscale values ​​of 0 to 255, the grayscale threshold value is 16, and the modified grayscale value is 240 or greater.

8. A hybrid driving method for driving a cholesteric liquid crystal display device to improve a display effect of gray scale and contrast of a screen of a display panel, comprising: The cholesteric liquid crystal display device includes a plurality of display units for displaying the screen, A predetermined range of grayscale depth is preset on the screen so that each of the plurality of display units has a unit corresponding grayscale value corresponding to the display unit, and a grayscale threshold value corresponding to the range of grayscale depth is preset on the screen; The mixed driving method includes: preparing a plurality of display grayscale values ​​to be displayed on the plurality of display units in accordance with the range of the grayscale depth, and changing the display grayscale values ​​that exceed the grayscale threshold value among the plurality of display grayscale values ​​to modified grayscale values ​​that are displayed in a light state color; driving the display panel based on the plurality of display grayscale values ​​changed by the changing step in a DDS driving mode to display the screen; a step of driving the display panel in a PWM drive mode based on the plurality of display grayscale values ​​before being changed in the changing step, to display the screen, after the display panel has been driven in the DDS drive mode; having The mixed driving method, wherein the PWM driving mode improves the display effect of gray scale and contrast of the screen.

9. 9. The mixed driving method according to claim 8, wherein the predetermined grayscale depth range of the screen is set to have the unit corresponding grayscale value of 0 to 255, the grayscale threshold value is 16, and the modified grayscale value is 240 or more.

10. 9. The mixed driving method according to claim 8, wherein a driving time ratio between the DDS driving mode and the PWM driving mode is 1:4.

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