CN113467119A - Local erasing pretreatment method for liquid crystal writing device - Google Patents

Local erasing pretreatment method for liquid crystal writing device Download PDF

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CN113467119A
CN113467119A CN202111035829.1A CN202111035829A CN113467119A CN 113467119 A CN113467119 A CN 113467119A CN 202111035829 A CN202111035829 A CN 202111035829A CN 113467119 A CN113467119 A CN 113467119A
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illumination
erasing
area
liquid crystal
induced current
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CN113467119B (en
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李清波
杨猛训
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Shandong Lanbeisite Educational Equipment Group
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Shandong Lanbeisite Educational Equipment Group
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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/13306—Circuit arrangements or driving methods for the control of single liquid crystal cells
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/136—Liquid crystal cells structurally associated with a semi-conducting layer or substrate, e.g. cells forming part of an integrated circuit
    • G02F1/1362—Active matrix addressed cells
    • G02F1/1368—Active matrix addressed cells in which the switching element is a three-electrode device
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/137—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
    • G02F1/139—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
    • G02F1/1391—Bistable or multi-stable liquid crystal cells
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0412—Digitisers structurally integrated in a display
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0416—Control or interface arrangements specially adapted for digitisers

Abstract

The invention provides a local erasing pretreatment method for a liquid crystal writing device, belonging to the technical field of liquid crystal writing boards, and the method comprises the following steps: acquiring a first illumination induced current of an illumination area caused by the light emission of the optical erasing piece and a second illumination induced current of an area with the same area as the illumination area in the non-erasing area and caused by ambient light; when the second illumination induction current value is larger than the set current value, adjusting the luminous intensity of the erasing piece so as to enable the proportion of the first illumination induction current to the second illumination induction current to be within a preset range; when the luminous intensity of the optical erasing piece reaches the upper regulation limit, the discharge frequency between the substrate layer and the conducting layer is controlled according to the proportion of the first illumination induced current and the second illumination induced current, so that the influence of ambient light is avoided; when the second illumination induction current value is smaller than or equal to the set current value, the voltage difference between the substrate layer and the conductive layer is controlled within a set range in the electrified non-erasing state, and the erasing speed is improved.

Description

Local erasing pretreatment method for liquid crystal writing device
Technical Field
The invention relates to the technical field of liquid crystal writing boards, in particular to a local erasing pretreatment method for a liquid crystal writing device.
Background
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The invention patent of patent number CN112684618B discloses a technical scheme for realizing local erasing of a liquid crystal writing device by illumination, which comprises a conductive layer, a bistable liquid crystal layer and a substrate layer sequentially arranged from top to bottom; a plurality of pixel units are arranged on the basal layer in an array mode, and each pixel unit is internally provided with a pixel electrode and a thin film field effect transistor TFT (TFT for short) connected with the pixel electrode; applying a set control voltage to the gate electrode of the TFT and applying a set input voltage to the source electrode of the TFT so that the TFT is in a critical cut-off state; applying a set voltage to the conductive layer; at this time, an erasing device (hereinafter referred to as an optical erasing member) applies light within a set intensity range to an area to be erased, so that the TFT in the area receiving the light is turned on, a set voltage is input to the corresponding pixel electrode, and when the voltage between the pixel electrode and the conductive layer reaches an erasing voltage of the liquid crystal, partial erasing can be performed.
In the scheme, if the illumination induced current of the TFT is large under the set light intensity, the voltage difference between the pixel electrode and the conducting layer in the non-erasing area caused by the ambient light can easily reach the erasing starting voltage more quickly, so that the handwriting in the non-erasing area can be lightened more quickly, the user experience is reduced, the illumination intensity of the existing optical erasing piece is fixed, the illumination intensity adjustment of the illumination intensity by the size of the adaptive illumination induced current and the ambient light intensity can not be realized, and the user experience is reduced; if the light induced current of the TFT is small under the set light intensity, the voltage change between the substrate layer and the liquid crystal layer is slow, and the set voltage difference between the pixel electrode and the conductive layer can reach the erasing voltage of the liquid crystal only by long time of light irradiation, so that the erasing time is long, and the erasing efficiency is reduced.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a local erasing pretreatment method of a liquid crystal writing device, when the intensity of ambient light is larger, the luminous intensity of an optical erasing piece is self-adaptively adjusted along with the intensity of the ambient light, when the luminous intensity of the optical erasing piece reaches the upper limit of adjustment, the adjustment of discharge frequency is carried out, and the problem of fast fading of the handwriting of a non-erasing area caused by the ambient light is effectively avoided; when the ambient light intensity is small, the voltage difference between the substrate layer and the conductive layer is controlled within a set range in the non-erasing state of electrification, and the erasing speed is improved.
In order to achieve the above object, according to a first aspect of the present invention, there is provided a local erasing preprocessing method of a liquid crystal writing apparatus, comprising:
acquiring a first illumination induced current of an illumination area caused by the light emission of the optical erasing piece and a second illumination induced current of an area with the same area as the illumination area in the non-erasing area and caused by ambient light;
when the second illumination induction current value is larger than the set current value, adjusting the luminous intensity of the erasing piece so as to enable the proportion of the first illumination induction current to the second illumination induction current to be within a preset range;
when the luminous intensity of the optical erasing piece reaches the upper regulation limit, controlling the discharge frequency between the substrate layer and the conducting layer according to the ratio of the first illumination induced current to the second illumination induced current;
and when the second illumination induction current value is less than or equal to the set current value, controlling the voltage difference between the substrate layer and the conductive layer within a set range in the electrified non-erasing state.
According to a second aspect of the present invention, there is provided a liquid crystal writing apparatus partial erasure preprocessing method including:
acquiring a first illumination induced current of an illumination area caused by the light emission of the optical erasing piece and a second illumination induced current of an area with the same area as the illumination area in the non-erasing area and caused by ambient light;
adjusting the luminous intensity of the erasing piece so that the ratio of the first illumination induction current to the second illumination induction current is within a preset range;
and when the luminous intensity of the optical erasing piece reaches the upper regulation limit, controlling the discharge frequency between the substrate layer and the conductive layer according to the ratio of the first illumination induced current and the second illumination induced current.
According to a third aspect of the present invention, there is provided an erasing control method of a liquid crystal writing apparatus adaptive to light induced current, comprising:
and controlling all or a set part of the TFTs on the substrate layer to be in a critical state, irradiating the TFTs by using light within a set intensity range emitted by the light erasing piece to realize local erasing, and executing the preprocessing method before the local erasing.
According to a fourth aspect of the present invention, there is provided a controller for loading and executing the above-mentioned local erasing preprocessing method for the liquid crystal writing apparatus; or the controller loads and executes the local erasing control method of the liquid crystal writing device.
According to a fifth aspect of the present invention, there is provided a liquid crystal writing apparatus, comprising a controller, the controller loading and executing the above-mentioned local erasing pre-processing method of the liquid crystal writing apparatus; or the local erasing control method of the liquid crystal writing device is loaded and executed by the controller to realize local erasing.
Compared with the prior art, the invention has the beneficial effects that:
1. when the second illumination induction current value is larger than the set current value, the light emitting intensity of the erasing piece is adjusted, so that the ratio of the first illumination induction current to the second illumination induction current is in a preset range, the illumination intensity adjustment of the light erasing piece self-adaptive illumination induction current is realized, and the erasing speed is improved.
2. When the luminous intensity of the optical erasing piece reaches the upper regulation limit, the discharge time interval between the substrate layer and the conducting layer is controlled according to the first illumination induction current and the second illumination induction current, and the problem of fading of the handwriting of a non-target erasing area caused by strong ambient light is effectively avoided.
3. When the second illumination induction current value is smaller than or equal to the set current value, the voltage difference between the substrate layer and the conductive layer is controlled within the set range in the power-up non-erasing state, and the erasing efficiency is improved.
Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
Fig. 1 is a schematic flow chart of a local erasing preprocessing method for a liquid crystal writing device according to embodiment 1 of the present invention.
Fig. 2 is a first TFT connection diagram provided in embodiment 1 of the present invention.
Fig. 3 is a second schematic connection diagram of a TFT according to embodiment 1 of the present invention.
Fig. 4 is a schematic diagram of an illuminated induced current detection circuit provided in embodiment 1 of the present invention.
Fig. 5 is a graph showing a variation relationship between the illumination time after the pre-applied voltage and the voltage difference between the substrate layer and the liquid crystal layer according to embodiment 1 of the present invention.
Fig. 6 is a graph showing a variation relationship between the illumination time without the pre-applied voltage and the voltage difference between the substrate layer and the liquid crystal layer according to embodiment 1 of the present invention.
Detailed Description
The invention is further described with reference to the following figures and examples.
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.
Example 1:
as shown in fig. 1, an embodiment 1 of the present invention provides a method for preprocessing a local erasure of a liquid crystal writing device, where the liquid crystal writing device includes: the liquid crystal display panel comprises a conducting layer, a bistable liquid crystal layer and a substrate layer which are sequentially arranged from top to bottom, wherein the conducting layer can be not divided, a plurality of pixel units are integrated on the substrate layer, the pixel units are arranged in an array mode, a pixel electrode and a TFT connected with the pixel electrode are arranged in each pixel unit, and the TFT can provide voltage for the pixel electrode connected with the TFT in a conducting mode.
Specifically, as shown in fig. 2 and fig. 3, wiring diagrams of the TFT are respectively given. In fig. 2, the first plate represents a pixel electrode region to which the TFT is connected on the base layer; the second plate represents a conductive layer; the drain electrode of the TFT can be also connected with a storage capacitor, the leading-out electrode wire of each storage capacitor is connected with the leading-out electrode wire of the conducting layer, and the TFT is switched on to charge the storage capacitors. In fig. 2, the storage capacitor C functions to prevent voltage abrupt change, but it is also possible to realize the function of the storage capacitor C by using a distributed capacitance formed between the conductive layer and the underlying layer itself, and in this case, the storage capacitor C may be omitted, as shown in fig. 3.
Light induced current of the thin film field effect transistor TFT:
I=f(area of light-transmitting opening, channel material and Process, storage capacitor C, intensity of light)
It can be seen that the illumination induced current of the TFT is determined by the area of the light-transmitting opening, the channel material and process, the storage capacitor C, and the intensity of light received, and different channel materials and processes, the storage capacitor C, the area of the light-transmitting opening, and the intensity of light received all cause the variation of the illumination induced current of the TFT.
The pretreatment method comprises the following steps:
and controlling all or a set part of the TFTs on the substrate layer to be in a critical state, and acquiring a first illumination induced current in an illumination area caused by the light emission of the optical erasing piece and a second illumination induced current caused by ambient light in an area with the same area as the illumination area in the non-erasing area.
Specifically, as shown in FIG. 4, a high potential V is first applied to the gate G of the TFTHAnd causes switch S to close, VDC=VCOMThen, the switch S is opened to give the gate G of the TFT a control point Vg，VsGrounding, wherein the TFT is in critical cut-off state, and when the TFT is simultaneously irradiated by the light erasing part and the ambient light, the light induced current I of the single TFT is caused by the light erasing part and the ambient light1Comprises the following steps:
I1=Ioptical erasing piece+IAmbient light=V0/R1
When the light of the light erasing part is closed, the change of the intensity of the ambient light can be ignored, and the single TFT light induced current I caused by the ambient light alone2Comprises the following steps:
I2=Iambient light=V0’/R1
The light induced current I of the single TFT caused by the light of the light erasing member alone3Comprises the following steps:
I3= I1- I2
in this example, V0And V0' are both R1Voltage across, R1First end of (1) and (V)sIs connected to R1With the second terminals of the TFT and the source and R of the TFT, respectively2Is connected to the first end of R by2Series-connected voltage-dividing resistor R3By mixing R2Second terminal of (2) and R3Is connected to a first end of R3Is grounded so that R2And R3In the readable range of the processor by reading R2Second terminal of (2) and R3To obtain V0And V0’。
The critical cutoff state specifically includes: applying a set voltage to the conductive layer, and applying a set control voltage and an input voltage to the TFT electrode respectively; when receiving illumination with set illumination intensity, the TFT is conducted; and when not irradiated by the light of the set light intensity, the TFT is in the off state.
It should be understood that the circuit diagram shown in fig. 3 of this embodiment is only a preferred example, and those skilled in the art can select the circuit diagram to implement I according to specific operating conditions1、I2、I3The calculation of (a) may be performed as long as the corresponding current detection value can be obtained quickly, and a person skilled in the art may select the current detection value according to a specific working condition, which is not described herein again.
In this embodiment, the first illumination induced current is a product of an illumination induced current generated on the TFT by the light emission of the optical erasing member and the number of TFTs in the illumination area; alternatively, in some other embodiments, the first photo sense current is a sum of photo sense currents of the respective TFTs caused by the light emitting of the light erasing member at the light emitting region.
Assuming that the total writing area of the writing board is S, the light-irradiating area of the light-erasing member is S1The light induced current I caused by ambient light in the same area of the non-erasing area and the erasing area (i.e. the light irradiating area of the optical erasing member)Non-erasing area (illumination area)(i.e., the second illumination induced current) is:
Inon-erasing area (illumination area)=IAmbient light (general)*S1/S
At this time, IAmbient light (general)The light induced current generated by ambient light for the entire writing board when the light erasing member is not lighted, IIllumination areaLight induced current (i.e. first light induced current) caused by light emission of the light erasing member, INon-erasing area (illumination area)The light induced current (i.e. the second light induced current) in the non-erasing area and the erasing area caused by the ambient light.
When I isNon-erasing area (illumination area)When the light intensity is larger than the set value, the light intensity of the erasing piece is adjusted so as to enable the light intensity to be IIllumination areaAnd INon-erasing area (illumination area)Is within a preset multiple range.
The preset multiple range is determined according to the relationship between the TFT photocurrent and the illumination intensity, preferably, in this embodiment, the minimum value of the preset multiple range is selected to be 4 times, i.e. IIllumination area≥4INon-erasing area (illumination area)It can be understood that, in some other embodiments, the minimum value of the preset multiple may also be 2 times, 3 times, 5 times, or other integer or non-integer multiple greater than or equal to 2, and a person skilled in the art may select the minimum value according to a specific working condition, and details are not described here.
In this embodiment, when the light intensity of the optical erasing element reaches the upper adjustment limit, the current I is induced according to the first illumination currentIllumination areaAnd a second illumination induced current INon-erasing area (illumination area)The ratio of the voltage difference between the power-up and the erase start voltage caused by the ambient light in the non-erase region and the power-up and the discharge in the erase region is greater than a preset amount; i.e. the first illumination induced current IIllumination areaAnd a second illumination induced current INon-erasing area (illumination area)The smaller the ratio of (A), the shorter the discharge time interval, the higher the discharge frequency, the first illumination induced current IIllumination areaAnd a second illumination induced current INon-erasing area (illumination area)The larger the ratio of (a) is, the longer the discharge time interval is, and the lower the discharge frequency is.
The preset amount can ensure that under the condition that the erasing area of the optical erasing piece is completely erased, the non-erasing area does not generate visual character fading caused by the irradiation of ambient light, and the preset amount is determined by the relationship between the TFT photocurrent and the illumination intensity. In particular, the current I is induced according to the second illuminationNon-erasing area (illumination area)Obtaining the first time when the pixel electrode in the non-erasing area and the pixel electrode in the erasing area reach the erasing potentialT 1 Inducing a current I according to the first illuminationIllumination areaObtaining a second time when the pixel electrode reaches the erase potential in the erase regionT 2 The preset amount is less than the first timeT 1 And the second timeT 2 Difference of (2)
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Those skilled in the art can readily appreciate that the ratio of the total weight of the composition is less than
Figure 830968DEST_PATH_IMAGE002
Is selected within a predetermined range.
Similarly, the set values are determined by the relationship between the TFT photocurrent and the illuminance, so as to ensure that the non-erased area is not visibly lighter due to ambient light irradiation when the optical erasing element erased area is completely erased.
In this embodiment, the powering up specifically includes:
applying set voltages to the gate and the source of all or a set part of TFTs on the substrate layer of the liquid crystal writing device respectively; the voltage can enable the TFT to be in a cut-off state when the TFT does not receive illumination within a set intensity range; the TFT can be conducted after receiving illumination within a set intensity range, and an erasing electric field can be formed between a voltage loaded on a pixel electrode connected with the TFT and the conducting layer, so that local erasing is realized;
the discharge between the substrate layer and the conductive layer is specifically as follows:
applying set voltages to the gate and the source of all or a set part of TFTs on the substrate layer of the liquid crystal writing device respectively; the voltage can turn on the TFT and cause a voltage difference formed between the base layer and the conductive layer to be zero or less than a voltage required for erasing the liquid crystal.
When I isNon-erasing area (illumination area)When the voltage is less than or equal to the set value, the voltage difference between the substrate layer and the conductive layer is controlled within the set voltage value range below the erasing voltage of the liquid crystal under the power-on non-erasing state.
When local erasing is carried out, all or a set part of TFTs on the substrate layer are controlled to be in a critical state, the TFTs are conducted when receiving illumination within a set intensity range, and the voltage difference between the corresponding pixel electrode and the conductive layer reaches the erasing voltage V of the liquid crystal on the basis of the value of the pre-charging voltageEThereby realizing the partial erase.
FIG. 5 is a graph showing the variation of the pre-charging light irradiation time and the voltage difference between the substrate layer and the liquid crystal layer, in this embodiment, the voltage difference between the substrate layer and the conductive layer is controlled to beThe voltage difference between the substrate layer and the conductive layer is within a set voltage range (such as voltage V) below the erase voltage of the liquid crystal0) On the basis, the voltage difference between the basal layer and the conducting layer is promoted, so that the time required from the illumination conduction of the TFT to the voltage difference between the basal layer and the conducting layer to reach the erasing voltage of the liquid crystal is greatly shortened, and the speed of local erasing is accelerated.
FIG. 6 is a graph showing the variation of the light irradiation time without pre-charging and the voltage difference between the substrate layer and the liquid crystal layer, comparing the voltage difference between the substrate layer and the conductive layer in FIG. 5 and FIG. 6 to the erasing voltage V of the liquid crystalEThe time required, it is evident that t0 < t1, is significantly shorter.
In this embodiment, the TFT is turned on by illumination, and a set voltage is input to the corresponding pixel electrode, so as to charge the storage capacitor, and when the voltage difference between the two ends of the storage capacitor reaches the erasing voltage of the liquid crystal, the local erasing in the region can be realized.
Specifically, firstly, applying set voltages to the gate electrode and the source electrode of the TFT respectively to enable all or set parts of the TFT on the substrate layer to be turned on, and applying set first voltages to corresponding pixel electrodes; applying a set second voltage to the conductive layer; thereby, a voltage difference between the base layer and the conductive layer is loaded to a set voltage range smaller than an erase voltage of the liquid crystal; since this voltage range is smaller than the erase voltage of the liquid crystal, the partial erase cannot be realized at this time.
The set voltage value range is determined by the erase voltage of the liquid crystal, the storage capacitor and the light conduction current; the setting can be performed according to actual needs.
Then, all the TFTs on the base layer are loaded to a critical state, a set third voltage value is applied to the conducting layer, so that when illumination within a set illumination intensity range is received, the TFTs can be conducted, and the voltage difference between the corresponding pixel electrode and the conducting layer can reach the erasing voltage of the liquid crystal, and local erasing is achieved.
And after the local erasing is finished, controlling the voltage difference between the substrate layer and the conductive layer to be within the set voltage value range.
It will be appreciated that in other embodiments, the voltage difference between the base layer and the conductive layer is discharged to zero after the partial erase is completed.
As a more specific embodiment, since the set erasing electric field is applied between the base layer and the conductive layer corresponding to the just erased area, these areas cannot be written again before the electric field is removed, which greatly affects the writing efficiency and writing experience.
Based on this, the present embodiment designs a local erase control method, which specifically includes the following processes:
defining the process of the erasing device from entering the writing area to leaving the writing area as an erasing process;
in the process of one-time erasing, the local erasing is realized by adopting the control method of the illumination erasing voltage of the liquid crystal writing device; and controlling the voltage difference between the substrate layer and the conductive layer to be within the set voltage range at set time intervals t, and then controlling all or a set part of the TFTs on the substrate layer to be in a critical state so as to realize local erasing again when receiving illumination within the set intensity range.
Meanwhile, the method can also comprise the following steps: in the process of one-time erasing, if the current position of the erasing device is in the set voltage value range from the voltage difference between the last base layer and the last conducting layer, the shortest distance between the positions of the erasing device exceeds a set value W, the voltage difference between the base layer and the conducting layer is controlled to be in the set voltage range, and then all or a set part of TFTs on the base layer are controlled to be in a critical state, so that when illumination within the set intensity range is received, local erasing is realized again.
And when the erasing process is finished, discharging the voltage difference between the substrate layer and the conductive layer to zero.
In the erasing process, the voltage difference between the base layer and the conducting layer is controlled to the set voltage range every set time t, on one hand, the time required by next local erasing is shortened, on the other hand, the interval time for rewriting after local erasing can be shortened, the writing can be realized while erasing, the writing efficiency is improved, and the writing experience of a user is improved.
Example 2:
the embodiment 2 of the invention provides a local erasing pretreatment method for a liquid crystal writing device, which comprises the following steps:
acquiring a first illumination induced current of an illumination area caused by the light emission of the optical erasing piece and a second illumination induced current of an area with the same area as the illumination area in the non-erasing area and caused by ambient light;
adjusting the luminous intensity of the erasing piece so that the ratio of the first illumination induction current to the second illumination induction current is within a preset range;
and when the luminous intensity of the optical erasing piece reaches the upper regulation limit, controlling the discharge frequency between the substrate layer and the conductive layer according to the ratio of the first illumination induced current and the second illumination induced current.
The specific calculation method of the induced current, the adjustment method of the light emission intensity of the erasing member, and the adjustment strategy of the discharge frequency are the same as those in embodiment 1, and are not described again here.
Example 3:
the embodiment 3 of the invention provides an erasing control method of a liquid crystal writing device capable of adapting to illumination induced current, which comprises the following steps:
controlling all or a set part of TFTs on the substrate layer to be in a critical state, irradiating the TFTs with light within a set intensity range emitted by the light erasing piece to realize local erasing, and executing the preprocessing method described in embodiment 1 or embodiment 2 before the local erasing.
Example 4:
embodiment 4 of the present invention provides a controller, where the controller loads and executes the local erasing preprocessing method of the liquid crystal writing device described in embodiment 1 or embodiment 2; alternatively, the controller loads and executes the liquid crystal writing device local erasure control method described in embodiment 3.
Example 5:
embodiment 5 of the present invention provides a liquid crystal writing device, including a controller, where the controller loads and executes the local erasure preprocessing method of the liquid crystal writing device described in embodiment 1 or embodiment 2; or, the liquid crystal writing device comprises a controller, and the controller loads and executes the local erasing control method of the liquid crystal writing device in embodiment 3 to realize local erasing.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A local erasing pretreatment method for a liquid crystal writing device is characterized by comprising the following steps:
acquiring a first illumination induced current of an illumination area caused by the light emission of the optical erasing piece and a second illumination induced current of an area with the same area as the illumination area in the non-erasing area and caused by ambient light;
when the second illumination induction current value is larger than the set current value, adjusting the luminous intensity of the erasing piece so as to enable the proportion of the first illumination induction current to the second illumination induction current to be within a preset range;
when the luminous intensity of the optical erasing piece reaches the upper regulation limit, controlling the discharge frequency between the substrate layer and the conducting layer according to the ratio of the first illumination induced current to the second illumination induced current;
and when the second illumination induction current value is less than or equal to the set current value, controlling the voltage difference between the substrate layer and the conductive layer within a set range in the electrified non-erasing state.
2. A local erasing pretreatment method for a liquid crystal writing device is characterized by comprising the following steps:
acquiring a first illumination induced current of an illumination area caused by the light emission of the optical erasing piece and a second illumination induced current of an area with the same area as the illumination area in the non-erasing area and caused by ambient light;
adjusting the luminous intensity of the erasing piece so that the ratio of the first illumination induction current to the second illumination induction current is within a preset range;
and when the luminous intensity of the optical erasing piece reaches the upper regulation limit, controlling the discharge frequency between the substrate layer and the conductive layer according to the ratio of the first illumination induced current and the second illumination induced current.
3. The local erasing pretreatment method of the liquid crystal writing apparatus as set forth in claim 1 or 2,
the first illumination induced current is: the product of the illumination induced current generated on the TFT by the light emitted by the optical erasing part and the number of the TFTs in the illumination area; alternatively, the light erasing member emits light to cause addition of light induced currents of the respective TFTs in the light emitting region.
4. The local erasing pretreatment method of the liquid crystal writing apparatus as set forth in claim 1 or 2,
the second illumination induced current is: the product of the total illumination induced current generated by the ambient light on the liquid crystal writing device and the illumination area of the optical erasing part is divided by the total writing area of the liquid crystal writing device.
5. The local erasing pretreatment method of the liquid crystal writing apparatus as set forth in claim 1 or 2,
the first illumination induced current of the illumination area caused by the light emission of the optical erasing part is as follows: the difference value of the illumination induced current generated when the light erasing piece emits light and the ambient light simultaneously irradiates the illumination area and the illumination induced current generated when the ambient light singly irradiates the illumination area.
6. The local erasing pretreatment method of the liquid crystal writing apparatus as set forth in claim 1 or 2,
the preset range is as follows: the ratio of the first photo-induced current to the second photo-induced current is greater than or equal to 2.
7. An erasing control method of a liquid crystal writing device adaptive to illumination induced current is characterized by comprising the following steps:
controlling all or a set part of TFTs on the substrate layer to be in a critical state, utilizing illumination within a set intensity range emitted by the optical erasing piece to realize local erasing, and executing the preprocessing method in claim 1 or 2 before the local erasing.
8. A controller, characterized in that the controller loads and executes the liquid crystal writing device partial erasure preprocessing method of claim 1 or 2.
9. A controller, wherein the controller loads and executes the method for controlling erasing of a liquid crystal writing device with adaptive illumination induced current of claim 7.
10. A liquid crystal writing apparatus, comprising a controller which loads and executes the liquid crystal writing apparatus partial erasure preprocessing method of claim 1 or 2;
or, a controller is included, and the controller loads and executes the liquid crystal writing device local erasing control method of claim 7 to realize local erasing.
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JPH0915571A (en) * 1995-06-28 1997-01-17 Sharp Corp Optical writing type liquid crystal light valve
US5608666A (en) * 1993-03-24 1997-03-04 Semiconductor Energy Laboratory Co., Ltd. Optical memory apparatus using first and second illuminating lights for writing and reading
CN102639329A (en) * 2010-09-10 2012-08-15 株式会社理光 Laser erasing apparatus and laser erasing method
CN106935219A (en) * 2017-03-31 2017-07-07 山东蓝贝易书信息科技有限公司 A kind of key of luminous energy liquid crystal writing plate one erasing control circuit system
CN112684618A (en) * 2020-11-30 2021-04-20 山东蓝贝思特教装集团股份有限公司 Liquid crystal writing device and method for realizing local erasing by utilizing illumination
CN113284471A (en) * 2021-06-28 2021-08-20 山东蓝贝思特教装集团股份有限公司 Local erasing control method and system for liquid crystal writing device based on illumination erasing

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5608666A (en) * 1993-03-24 1997-03-04 Semiconductor Energy Laboratory Co., Ltd. Optical memory apparatus using first and second illuminating lights for writing and reading
JPH0915571A (en) * 1995-06-28 1997-01-17 Sharp Corp Optical writing type liquid crystal light valve
CN102639329A (en) * 2010-09-10 2012-08-15 株式会社理光 Laser erasing apparatus and laser erasing method
CN106935219A (en) * 2017-03-31 2017-07-07 山东蓝贝易书信息科技有限公司 A kind of key of luminous energy liquid crystal writing plate one erasing control circuit system
CN112684618A (en) * 2020-11-30 2021-04-20 山东蓝贝思特教装集团股份有限公司 Liquid crystal writing device and method for realizing local erasing by utilizing illumination
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