CN109856881B

CN109856881B - High-brightness liquid crystal writing device

Info

Publication number: CN109856881B
Application number: CN201910294348.9A
Authority: CN
Inventors: 郑明炜
Original assignee: Guangzhou Lindeng Technology Co ltd
Current assignee: Guangzhou Lindeng Technology Co ltd
Priority date: 2019-04-12
Filing date: 2019-04-12
Publication date: 2021-09-21
Anticipated expiration: 2039-04-12
Also published as: CN109856881A; WO2020207346A1

Abstract

A high brightness liquid crystal writing apparatus comprising: at least two layers of display material, the layers of display material comprising cholesteric liquid crystals; at least one intermediate support layer disposed between each two display material layers; the two sides of each display material layer are respectively provided with an erasing conductive layer, when at least one part of each erasing conductive layer at the two sides of the display material layer is respectively connected with an erasing voltage signal, an electric field is formed between the connected parts of the two erasing conductive layers, and writing traces of the area of the display material layer which is relatively covered by the electric field are erased. Therefore, the invention reserves the scheme of double-layer display material layers in the prior art (but the invention is not limited to double layers), and two erasing conductive layers positioned at two sides of each display material layer are respectively arranged to erase the display material layers independently so as to solve the problem of overlarge erasing voltage, and meanwhile, incident light can be doubly reflected by two or more display material layers so as to achieve the effect of enhancing brightness.

Description

High-brightness liquid crystal writing device

Technical Field

The invention relates to a liquid crystal writing device.

Background

At present, cholesteric liquid crystal is mostly adopted as a liquid crystal display material for a liquid crystal writing screen. The cholesteric liquid crystal is formed by adding a chiral agent in a proper proportion to the nematic liquid crystal, and the chiral agent makes the long axis direction of each layer of molecules of the multilayer nematic liquid crystal gradually rotate by an angle to form a spiral shape. This structure is similar to the cholesterol molecules in animals, so it is called cholesterol liquid crystal, also called cholesteric liquid crystal. Cholesteric liquid crystals have 3 different molecular alignment structures, the first of which is a planar Texture (P-state); the second is Focal Cone Texture (FC) state; the third is a vertical Texture (Homeotropic Texture) called H-state. In the P state, the cholesteric liquid crystal reflects light with specific wavelength to generate Bragg reflection, the wavelength of the reflected light is controlled by the pitch, and the pitch can be controlled by the variety and the adding proportion of the chiral agent. The color of the reflected light can be adjusted by adjusting the variety and proportion of the chiral agent. When a predetermined electric field is applied to the cholesteric liquid crystal in the P state by an electronic circuit, the cholesteric liquid crystal is switched from the P state to the FC state. The cholesteric liquid crystal in the FC state is a multi-domain structure, the distribution of the spiral shaft is disordered, and the scattering is generated on incident light. When an object with certain hardness, such as a nail, a pen and the like, is used for writing on the first substrate layer, the liquid crystal is locally displaced at the writing position, the writing position is converted from the FC state to the P state through the flow generated in the liquid crystal, and Bragg reflection is generated to display the writing strokes. The cholesteric liquid crystal can be changed from a P state to an FC state by methods of electric field, heating or illumination and the like, so that the cholesteric liquid crystal is scattered without reflecting light, thereby erasing strokes and writing information.

In order to enhance the brightness, chinese patent application No. CN201810687273.6 discloses a liquid crystal writing device, and in the second embodiment, it discloses that the display material layer is composed of an upper display material layer, a liquid crystal isolation layer and a lower display material layer which are sequentially stacked, and its purpose is to make the reflected light have a left-handed component and a right-handed component at the same time by the arrangement of the upper and lower display material layers, and enhance the brightness by the complementation of the reflected light in different vibration directions, thereby enhancing the brightness of the written strokes. Under the technical idea, in order to eliminate the writing marks displayed by the upper display material layer and the lower display material layer, the technical scheme is that an erasing conductive layer is respectively arranged above and below the upper display material layer and the lower display material layer to form an erasing electric field. However, since the liquid crystal isolation layer is used as an isolation and support substrate between the upper display material layer and the lower display material layer, it needs to have a certain hardness (in this application, a PET film or a half-wave plate is used), and the thickness of the liquid crystal isolation layer is often large, so that a large erasing voltage needs to be applied between the upper display material layer and the lower display material layer to form a sufficient electric field for erasing, and the erasing voltage is too large, which brings great disadvantages to the whole scheme of the liquid crystal writing device.

Disclosure of Invention

It is an object of the present invention to provide a high brightness liquid crystal writing device to solve the above problems.

According to an aspect of the present invention, there is provided a high brightness liquid crystal writing apparatus including:

at least two layers of display material, the layers of display material comprising cholesteric liquid crystals;

at least one intermediate support layer disposed between each two display material layers;

the two sides of each display material layer are respectively provided with an erasing conductive layer, so that the display material layer and the two erasing conductive layers on the two sides of the display material layer form a liquid crystal writing layer, when at least one part of each erasing conductive layer on the two sides of the display material layer is respectively connected with an erasing voltage signal, an electric field is formed between the connected parts of the two erasing conductive layers, and writing traces of the area of the display material layer which is relatively covered by the electric field are erased.

Therefore, in the invention, under the scheme of reserving two display material layers in the prior art (but the invention is not limited to double layers), two erasing conductive layers positioned on two sides of each display material layer are respectively arranged for each display material layer to independently erase the display material layers, namely, a supporting layer which is positioned in one liquid crystal writing layer and influences erasing voltage in the prior art is removed or transferred, so that the problem of overlarge erasing voltage is solved, and meanwhile, incident light can be doubly reflected by two or more display material layers to achieve the effect of enhancing brightness.

In some embodiments, all of the layers of display material are either the same left-handed cholesteric liquid crystal having the same reflective wavelength or the same right-handed cholesteric liquid crystal having the same reflective wavelength.

In the prior art, two display material layers adopt different-rotation cholesteric liquid crystals (namely, left-rotation cholesteric liquid crystals and right-rotation cholesteric liquid crystals respectively), during production, liquid crystals with specific reflection wavelengths in one rotation direction need to be prepared to obtain liquid crystals which are consistent with the reflection wavelengths of the original liquid crystals and opposite in rotation direction, the preparation process has extremely high operation requirements, and left-rotation and right-rotation liquid crystals with completely consistent reflection wavelengths (the error of +/-3 nanometers can be allowed) are difficult to obtain, so that a large short plate exists in industrial manufacturing. The invention adopts the homotropic liquid crystal (namely, the homotropic liquid crystal is the cholesteric liquid crystal which is homotropic or homotropic), can greatly simplify the process, improves the feasibility on industrial manufacture, and simultaneously, because the double reflection is carried out on incident light by adopting the double layers or more than the double layers of display material layers, the brightness can also be ensured.

In some embodiments of the present invention, the substrate is,

the middle supporting layer is a non-conductive layer;

the erasing conductive layers on two sides of each display material layer are respectively a first erasing conductive layer and a second erasing conductive layer, when at least one part of the first erasing conductive layer is connected with a first erasing voltage signal, and at least one part of the second erasing conductive layer is connected with a second erasing voltage signal, an electric field is formed between the connected part of the first erasing conductive layer and the connected part of the second erasing conductive layer, and writing marks of the area of the display material layer which is relatively covered are erased.

Under the scheme, the arrangement position of the supporting layer in the prior art is equivalently transferred, the middle supporting layer is prevented from influencing erasing voltage, and the middle supporting layer does not bear the erasing conductive function but only bears the supporting function, so that the freedom degree of selecting materials and thickness arrangement of the middle supporting layer is enlarged, the feasibility of industrial manufacturing is increased, and the supporting effect is enhanced.

In some embodiments of the present invention, the substrate is,

the middle supporting layer is a middle conducting layer;

at least one of the erase conductive layers on both sides of each display material layer is implemented as a middle conductive layer.

Under the scheme, the support layer in the prior art is replaced by the erasing conductive layer, the liquid crystal writing layer is respectively formed by the support layer and the other two erasing conductive layers of the two display material layers, the middle support layer plays a role in erasing conductive function and plays a certain supporting function (cholesteric liquid crystals in the two display material layers are isolated and do not permeate into each other, the writing pressure borne by the liquid crystal writing device is played, and the stable structure of the two display material layers is kept under the writing pressure).

In some embodiments, the intermediate support layer is a PET film.

Therefore, the supporting effect of the middle supporting layer is better.

In some embodiments, the liquid crystal display further comprises a first substrate layer and a second substrate layer arranged on two sides of the liquid crystal writing layer and the middle support layer.

Therefore, the liquid crystal display device is supported by the first base material layer, the second base material layer and the middle supporting layer together to form a stable structure.

In some embodiments, the erasing conductive layer is formed on the surface of the first substrate layer, the intermediate support layer and the second substrate layer respectively.

Thus, the manufacture of the erasing conductive layer is facilitated.

In some embodiments, an insulating layer is further disposed between the first erase conductive layer and/or the second erase conductive layer and the display material layer.

This can enhance the insulation between the first erase conductive layer and the second erase conductive layer.

In some embodiments, the insulating layer comprises any one of polyimide, polyimide acid or polyvinyl alcohol, and is rubbed to form a liquid crystal alignment layer;

or, the insulating layer comprises a first insulating sub-layer and a second insulating sub-layer which are laminated; the first insulating sublayer comprises any one or more of silicon dioxide, gelatin, polyvinyl acetate and polyurethane three-proofing paint; coating a second insulating sublayer on the first insulating sublayer; the second insulating sub-layer comprises polyimide, which is rubbed to form a liquid crystal alignment layer.

Thus, the brightness of the liquid crystal writing device can be further increased by forming the liquid crystal alignment layer.

In some embodiments, a plurality of conductive blocks insulated from each other are disposed in at least one of the first erasing conductive layer and the second erasing conductive layer of each liquid crystal writing layer to form a conductive block array;

when at least one conductive block is connected with the second erasing voltage signal, and the conductive block of the other erasing conductive layer opposite to the conductive block or the whole erasing conductive layer is connected with the first erasing voltage signal, an electric field is formed between the conductive block and the conductive block of the other erasing conductive layer or the whole erasing conductive layer, and the writing trace of the area of the display material layer covered by the conductive block is erased.

Thus, the local erasing function of the liquid crystal writing device can be realized through the conductive block array.

In some embodiments, the conductive blocks are uniformly arranged, equally sized blocks of square, rectangular, parallelogram, or hexagonal shape.

Therefore, the conductive block with the shape is convenient to manufacture and easy to realize a local erasing function.

In some embodiments, the first erasing conductive layer of each liquid crystal writing layer is provided with a plurality of first conductive strips which are arranged in parallel and insulated from each other, the second erasing conductive layer of each liquid crystal writing layer is provided with a plurality of second conductive strips which are arranged in parallel and insulated from each other, and the first conductive strips and the second conductive strips are staggered from each other;

when at least one first conductive strip is connected with a first erasing voltage signal, and at least one second conductive strip is connected with a second erasing voltage signal, an electric field is formed between the first conductive strips and the second conductive strips, and writing traces of the area of the display material layer which is covered relatively are erased.

Therefore, the local erasing function of the liquid crystal writing device is realized through the first conductive strips and the second conductive strips which are mutually staggered.

In some embodiments, the first conductive strip and the second conductive strip are perpendicular to each other.

Therefore, the first conductive strips and the second conductive strips in the shape are convenient to manufacture, and the local erasing function is easy to realize.

In some embodiments of the present invention, the substrate is,

the first base material layer is a transparent PET film with a frosted effect;

the middle supporting layer is a transparent PET film without frosting effect;

the second substrate layer is a black film without a frosting effect.

This can improve the display effect of the liquid crystal writing device and the comfort of the user.

In some embodiments, the erase voltage signal is a fixed voltage value voltage signal, a periodic voltage pulse signal with uniform amplitude, or a voltage pulse signal with non-uniform amplitude and time interval.

Thereby, it is possible to facilitate application of the erasing voltage signal to the erasing conductive layer to effect the erasing.

Drawings

Fig. 1 is a schematic structural diagram of a liquid crystal writing screen according to a first embodiment of the present invention;

fig. 2 is a schematic connection diagram of an electronic circuit and a liquid crystal writing screen according to a first embodiment of the invention;

FIG. 3 is a schematic diagram of light reflection according to a first embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a conductive block and an external contact point according to a second embodiment of the present invention;

fig. 5 is a schematic structural view of a liquid crystal writing screen according to a second embodiment of the present invention;

FIG. 6 is a schematic diagram of the connection between the electronic circuit and the LCD writing panel according to the second embodiment of the present invention;

fig. 7 is a schematic structural diagram of a liquid crystal writing screen and a key input device according to a third embodiment of the present invention;

fig. 8 is a schematic structural diagram of a liquid crystal writing screen and a key input device according to a third modified embodiment of the present invention;

fig. 9 is a schematic structural diagram of a key input device according to a third modified embodiment of the present invention;

fig. 10 is a schematic structural view of a liquid crystal writing panel according to a fourth embodiment of the present invention;

fig. 11 is a schematic structural diagram of a first conductive strip, a second conductive strip and a display material layer according to a fourth embodiment of the invention.

Fig. 12 is a schematic structural diagram of a first conductive strip, a second conductive strip and an external electrode according to a fourth embodiment of the present invention;

fig. 13 is a schematic connection diagram of an electronic circuit and a liquid crystal writing panel according to a fourth embodiment of the present invention.

Fig. 14 is a schematic structural view of a liquid crystal writing panel according to a fifth embodiment of the present invention;

fig. 15 is a schematic structural diagram of a liquid crystal writing panel according to a fifth modified embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Example one

The liquid crystal writing device of the first embodiment includes a liquid crystal writing panel 100 and an electronic circuit 180. The liquid crystal writing screen 100 is shown in fig. 1, and includes three substrate layers and two liquid crystal writing layers, specifically, a first substrate layer 110, a first liquid crystal writing layer, a middle support layer 170, a second liquid crystal writing layer, and a second substrate layer 190, which are stacked in sequence.

The first liquid crystal writing layer and the second liquid crystal writing layer have the same structure, and respectively include a display material layer, two erasing conductive layers located on the upper and lower sides of the display material layer, and two insulating layers respectively located between the erasing conductive layers and the display material layer, specifically, a first erasing conductive layer 120, a first insulating layer 130, a display material layer 140, a second insulating layer 150, and a second erasing conductive layer 160, which are sequentially stacked. In this embodiment, the order of the layered structures of the first liquid crystal writing layer and the second liquid crystal writing layer is a mirror image structure with reference to the middle support layer 170, but in other embodiments, a completely uniform structure may be used.

The first erase conductive layer 120 and the second erase conductive layer 160 are complete conductive layers, and have conductive synapses protruding from their edges for connection to the electronic circuit 180 for receiving the first erase voltage signal and the second erase voltage signal, respectively, to form an electric field between the first erase conductive layer 120 and the second erase conductive layer 160, thereby erasing the written trace in the display material layer 140.

The first insulating layer 130 and the second insulating layer 150 function to enhance the insulation between the erase conductive layer and the liquid crystal display layer, and in other embodiments, the first insulating layer 130 and the second insulating layer 150 or both of them may be omitted. Preferably, each of the insulating layers includes any one of PI (Polyimide), PA (polyamide Acid), or PVA (Polyvinyl alcohol), and has a function of a liquid crystal alignment layer after rubbing alignment; alternatively, the insulating layer includes a first insulating sublayer and a second insulating sublayer stacked; the first insulating sublayer comprises any one or more of silicon dioxide, gelatin, polyvinyl acetate and polyurethane three-proofing paint; coating a second insulating sublayer on the first insulating sublayer; the second insulating sub-layer comprises PI (Polyimide), which after rubbing alignment has the role of a liquid crystal alignment layer. The liquid crystal alignment can further increase the brightness.

In this embodiment, the middle support layer 170 is specifically an insulating middle substrate layer, and is similar to the material of the first substrate layer 110 and the second substrate layer 190. Because the liquid crystal writing screen needs to be used for writing, the first substrate layer 110, the middle support layer 170 and the second substrate layer 190 cannot be made of rigid materials, and flexible materials are needed to realize partial pressing of strokes, liquid crystal is allowed to flow, meanwhile, the pressure of the written strokes can be borne, the stability of the structure of each layer of the liquid crystal writing screen is kept under the pressure of the strokes, and therefore the insulating substrate with certain hardness needs to be used to play a supporting role. In this embodiment, the first substrate layer 110, the middle support layer 170 and the second substrate layer 190 are all PET (polyethylene terephthalate) films, wherein the thickness of the first substrate layer 110 is 20 to 200 μm, the thickness of the middle support layer 170 is 20 to 150 μm, and the thickness of the second substrate layer 190 is 20 to 300 μm. The first substrate layer 110 is a light source incident direction and is also a side on which a user reads and writes, and thus the first substrate layer 110 is provided as a transparent film, preferably with a frosted antiglare effect, while being reinforced to extend the service life. Since the hard tip is frequently rubbed on the first substrate layer 110 during writing, it is quickly worn and cannot be used without being subjected to a strengthening treatment. The middle support layer 170 is a pure transparent film, without frosting or antiglare effect. The second substrate layer 190 is used for displaying the ground color of the liquid crystal writing device, is made of a light-proof material, can be a black film, and has no frosting or anti-dazzle effect.

The erasing conductive layer is distributed on the surface of the substrate layer, specifically, the first erasing conductive layer 120 of the first liquid crystal writing layer, the second erasing conductive layer 160 of the second liquid crystal writing layer, and the first erasing conductive layer 120 of the second liquid crystal writing layer are respectively formed on the lower surface of the first substrate layer 110, the upper surface of the middle support layer 170, the lower surface of the middle support layer 170, and the upper surface of the second substrate layer 190, preferably, a transparent ITO (indium tin oxide) coating layer is formed on the surface of the substrate layer by sputtering, the thickness is 200 to 1800 angstroms, and the sheet resistance is 100 Ω to 1K Ω. Then, a transparent insulating ink is printed on the ITO-plated layer by screen printing or jet printing to form insulating layers having a thickness of 0.5 to 20 μm, i.e., the first insulating layer 130 and the second insulating layer 150 of the first liquid crystal writing layer and the second liquid crystal writing layer.

And finally, uniformly coating liquid crystal with the thickness of 2.5-5 μm between the first insulating layer 130 and the second insulating layer 150 of the first liquid crystal writing layer and the second liquid crystal writing layer in an extrusion coating mode to form a display material layer 140, wherein the liquid crystal adopts polymer dispersed cholesteric liquid crystal.

The writing film made of the polymer dispersed cholesteric liquid crystal does not use ink or chalk, is easy and convenient to erase, can be erased and written repeatedly, and has extremely low power consumption, so that the writing film is widely popular. However, this type of product has the disadvantage of insufficient brightness. The problem of brightness is not particularly obvious when the liquid crystal display device is used in a short distance such as a hand-held or desktop, but when the liquid crystal display device is used in a long distance such as a conference room whiteboard or a classroom blackboard, the brightness is insufficient, and when the liquid crystal display device is located at a position other than about 8 meters, the content written on the liquid crystal writing film is not clearly seen.

In this embodiment, the display material layer 140 of the first liquid crystal writing layer and the display material layer 140 of the second liquid crystal writing layer are cholesteric liquid crystals with the same reflection wavelength, which are both left-handed cholesteric liquid crystals or right-handed cholesteric liquid crystals. Since the light reflected by the left-handed cholesteric liquid crystal is left-handed polarized light and the light reflected by the right-handed cholesteric liquid crystal is right-handed polarized light, when the two display material layers 140 are both left-handed or right-handed cholesteric liquid crystals, the reflected light is either left-handed polarized light or right-handed polarized light, and the vibration directions are the same. The applicant has found that the mutual superposition of polarized light with the same vibration direction as reflected by the left-handed or right-handed cholesteric liquid crystal can significantly enhance the brightness. Meanwhile, because the cholesteric liquid crystal which is left-handed or right-handed (same-handed) is selected as the display material layer 140, the liquid crystal does not need to be prepared, the process is greatly simplified, and the feasibility in industrial manufacturing is improved.

In addition, under the technical conception of the prior art of the hetero-rotation (both left-rotation and right-rotation) cholesteric liquid crystal, at least two layers of display material layers are required to be arranged for the simultaneous existence of the liquid crystal with two rotation directions, because the display material layers need to be mutually isolated, and the mutual permeation of the left-rotation liquid crystal and the right-rotation liquid crystal is prevented, so that the display effect is damaged. However, the applicant has found that the use of two (or more) layers of display material increases the reflectivity of incident light, thereby achieving the effect of enhancing brightness. As shown in fig. 3, the incident light is first incident on the display material layer 140 of the first liquid crystal writing layer, part of the light is reflected, and the rest of the light reaches the display material layer 140 of the second liquid crystal writing layer through the middle support layer 170 and is reflected. The arrangement of the double-layer display material layer can reflect the residual light which is not successfully reflected by the first display material layer through the second display material layer, and effectively increases the reflectivity of incident light. The applicant experiments prove that the brightness of the display material layer adopting two layers can be improved by 10 to 15 percent compared with the brightness of the display material layer adopting a single layer. Therefore, the proposal of the homorotation multilayer liquid crystal can also achieve the effect of enhancing the brightness, and simultaneously can greatly simplify the process and improve the feasibility on industrial manufacture.

Preferably, the liquid crystal is Polymer Dispersed Cholesteric Liquid Crystal (PDCLC) which is formed by mixing cholesteric liquid crystal and polymer. The polymer of the polymer cholesteric liquid crystal has a crosslinking reaction under ultraviolet irradiation or after being heated for a certain time, and has a certain adhesive force, so that the mixture of the cholesteric liquid crystal and the polymer can be coated between two layers of flexible substrates and still has sufficient firmness and stability.

The electronic circuit 180 is shown in fig. 2, and includes a main controller, a voltage boost circuit, a first switch 1821, a second switch 1822, a lock button, and a full erase button. The locking key and the full erasing key are respectively connected with a main controller, the main controller is connected with the booster circuit, the first switch 1821 and the second switch 1822, the booster circuit is controlled to output a first erasing voltage signal and a second erasing voltage signal, and the first switch 1821 and the second switch 1822 are controlled to be switched on and off. The voltage boost circuit is connected to the synapses 1201 of the first erase conductive layer 120 of the first and second liquid crystal writing layers, respectively, through a first switch 1821, and the voltage boost circuit is connected to the synapses 1601 of the second erase conductive layer 160 of the first and second liquid crystal writing layers, respectively, through a second switch 1822.

The working principle of the liquid crystal writing device is as follows: when the lock key is pressed down, the main controller sends control signals to the first switch 1821 and the second switch 1822 to enable the first switch 1821 and the second switch 1822 to keep a normally-off state, and at the moment, even if the full-erase key is touched by mistake, any erasing operation cannot be executed; when the locking button is released and the all-erasing button is pressed, the main controller sends a control signal to the first switch 1821 and the second switch 1822 to close the first switch 1821 and the second switch 1822, and simultaneously sends a control signal to the voltage boost circuit, the voltage boost circuit receives the control signal and then outputs an erasing voltage signal, specifically, the voltage boost circuit outputs a first erasing voltage signal to the first erasing conductive layer 120 of the first liquid crystal writing layer and the second liquid crystal writing layer, and outputs a second erasing voltage signal to the second erasing conductive layer 160 of the first liquid crystal writing layer and the second liquid crystal writing layer. The erase voltage signal may be a continuous voltage or a voltage pulse. An electric field is formed between the first erasing conductive layer 120 and the second erasing conductive layer 160 of each liquid crystal writing layer to erase the writing traces in the entire display material layer 140. In other embodiments, the erasing conductive layer of each liquid crystal writing layer can be controlled by an independent switch to control the erasing operation of each liquid crystal writing layer respectively.

In other embodiments, the liquid crystal writing layers may be provided with three, four, five or more layers, each two layers being separated and supported by the middle support layer 170, but in general, the liquid crystal writing layers are preferably provided with two or three layers in consideration of the overall thickness of the liquid crystal writing screen 100 and the limitation of the residual light received and reflected by the fourth, fifth or more liquid crystal writing layers far from the light source.

In addition, because each liquid crystal writing layer is provided with the first erasing conductive layer 120 and the second erasing conductive layer 160 which are independent for each display material layer 140, so as to erase the display material layer 140, different from the prior art, a base material layer which can influence erasing voltage is not arranged between the first erasing conductive layer 120 and the second erasing conductive layer 160 of each liquid crystal writing layer, so that writing traces in the display material layer 140 can be erased only by small erasing voltage, the whole technical scheme of the liquid crystal writing device is easy to realize, and the liquid crystal writing device is greatly favorable for industrial manufacturing.

Example two

The main difference between the second embodiment and the first embodiment is that the liquid crystal writing device of the second embodiment can achieve partial erasing.

The liquid crystal writing panel 100 of the present embodiment differs from the first embodiment as follows:

the first erasing conductive layers 120 of the first and second liquid crystal writing layers are all complete conductive layers, and a plurality of conductive blocks 143 insulated from each other are disposed on the second erasing conductive layers 160 of the first and second liquid crystal writing layers to form a conductive block array, as shown in fig. 4. The conductive blocks 143 may be square, rectangular, parallelogram, hexagonal, or other uniformly arranged blocks with equal size, or blocks with different sizes, as long as the display material layer 140 can be partially covered and the erasing of the writing traces in the corresponding covered area can be realized.

The total writing area of the liquid crystal writing panel 100 was 1.2m × 0.8m, and the second erase conductive layer 160 was divided into 5 × 6 × 30 blocks each having an area of about 320cm²(the actual area of each block is slightly less than 320cm due to the gaps between the conductive blocks 143²) The conductive bumps 143 are about 20cm by 16cm in size. Preferably, an outer contact point is provided at the edge of the second erase conductive layer 160. The outer contact points of the second erase conductive layer 160 of the first liquid crystal writing layer were 261-u1, 261-u2, …, and 261-u30, and the outer contact points of the second erase conductive layer 160 of the second liquid crystal writing layer were 261-d1,261-d2, … and 261-d 30. One part of the conductive blocks is located at the edge of the second erase conductive layer 160 (including the case of directly attaching to the edge of the second erase conductive layer 160, or being close to the edge of the second erase conductive layer 160 but still having a certain insulation gap), the part of the conductive blocks can be directly electrically connected to an external contact point and led out from the edge of the second erase conductive layer 160, the other part of the conductive blocks is located in the middle of the second erase conductive layer 160, and other conductive blocks are spaced from the edge of the second erase conductive layer 160 and cannot be directly electrically connected to the external contact point, and for the part of the conductive blocks, the conductive blocks are electrically connected to the external contact point through the conductive traces 262 disposed on the second erase conductive layer 160. The external contact is connected with the booster circuit to realize the transmission of the erasing voltage signal.

As shown in fig. 5, a touch panel 200 for detecting a writing trace and touch point coordinates is further provided above the first base material layer 110, i.e., on the surface of the first base material layer 110 facing the outside. In other embodiments, the touch screen may be an optical touch screen, a projection touch screen, or a laser radar touch screen, which is also disposed above the first substrate layer 110, or the touch screen may be a resistive touch screen or an electromagnetic touch screen, which is disposed below the second substrate layer 190, that is, a surface of the second substrate layer 190 facing the outside.

As shown in fig. 6, the electronic circuit 180 of this embodiment includes a main controller, a first switch 1821, a second switch 1822, and a boost circuit, a channel selection array circuit, a USB interface, a WIFI module, a bluetooth module, a storage module, an OLED display screen, the infrared touch screen 200, a network adapter, and an office erasing key, a locking key, and a full erasing key electrically connected to the main controller. The synapses 1201 of the first erase conduction layer 120 of the first and second liquid crystal writing layers are connected to a voltage boost circuit through a first switch 1821. The main controller controls the on/off of the first switch 1821 through a control signal sent by the fourth control signal line 1831, so that the voltage boost circuit outputs a first erasing voltage signal to the synapse 1201 of the first erasing conductive layer 120 through the first output electrode 1833. The external contact points of the second erasing conductive layer 160 of the first and second liquid crystal writing layers are electrically connected to the boosting circuit through a second switch 1822, and specifically, the second switch 1822 has a plurality of external contact points, which are denoted as 261-u1, 261-u2, …, 261-u30 for the second erasing conductive layer 160 of the first liquid crystal writing layer, and 261-d1, 261-d2, …, 261-d30 for the second erasing conductive layer 160 of the second liquid crystal writing layer, and each external contact point is connected to the boosting circuit through one second switch 1822. The channel selection array circuit controls the on/off of the second switch 1822 according to a control signal sent by the main controller through the second control signal line 1814, so that the voltage boosting circuit outputs a second erasing voltage signal to the outer contact point of the second erasing conductive layer 160 corresponding to the erasing area through the second output electrode 1834. The infrared touch screen 200 is connected to the main controller to receive coordinate information of an erasing position touched by a user.

The working principle and method of the embodiment are as follows:

the voltage boosting circuit is used for outputting an erasing voltage signal, wherein the erasing voltage signal comprises a first erasing voltage signal and a second erasing voltage signal, and the erasing voltage signal can be continuous voltage or voltage pulse. The main controller is configured to store a mapping relation between the conductive blocks 143 and the erasing position information, obtain coordinate information of the erasing position from the infrared touch screen 200, determine the corresponding conductive blocks 143 according to the erasing position information, and control the output voltage of the boost circuit by using the PWM provided by the main controller. Under the condition that the area of the liquid crystal writing screen 100 is large, the booster circuit can be not only one path, but also two or more paths, so that the erasing area borne by each path of booster circuit is smaller, the erasing effect and the erasing speed can be improved, and the erasing voltage can also be properly reduced.

The channel selection array circuit is used for receiving a control signal of the main controller and controlling whether the voltage boosting circuit and the conductive block 143 are conducted or not through the second switch 1822. The channel selection array circuit is specifically realized by a gate array circuit, and channel control signals TC0, TC1, … and TC60 output by the gate array circuit correspond to external contact points 261-u1, 261-u2, …, 261-u30, 261-d1, 261-d2, … and 261-d30 in a one-to-one mode and are used for controlling the on-off of the second switch 1822. The channel selection array circuit has 3 working modes: the main controller selects the working mode according to different working conditions and gives instructions to the channel selection array circuit through a second control signal line 1814. In the on-site mode of operation, the second switch 1822 may only be closed one at a time; in the paired mode of operation, the second switch 1822 is closed 2 switches at a time; in full screen mode of operation, all of the second switches 1822 are closed at the same time.

Specifically, in the bit operation mode, the output channel control signals TC0, TC1, … and TC60 can only be valid one bit at a time, and the second switch array corresponding to the channel control signals TC0, TC1, TC 3526 and TC60 can only have one switch on at a time, so that the second output electrode 1834 of the voltage boost circuit is only conducted to one external contact point at a time, and only the external contact point and the synapse 1201 of the first erase conductive layer are applied with the erase voltage, so that an electric field is formed between the conductive block corresponding to the external contact point and the first erase conductive layer 120, and only the written trace in the area of the display material layer 140 covered by the conductive block and the first erase conductive layer 120 is erased.

The difference between the operating mode and the bit operating mode is that for each erasing in the operating mode, there are two conductive bumps, namely 261-ui and 261-di, i ═ 1,2, …,30, located at the same coordinate position of the first liquid crystal writing layer and the second liquid crystal writing layer, respectively. The channel control signals TC0, TC1, … and TC60 are valid for 2 bits at a time, and the second switches 1822 corresponding to the channel control signals TC0, TC1, TC 3526 and TC60 are closed for 2 bits at a time, so that writing traces on the same coordinate position of the first liquid crystal writing layer and the second liquid crystal writing layer can be simultaneously erased.

In the full screen operation mode, the channel control signal TC0 … 60 is active for 60 signals simultaneously, so that the written contents at 60 positions of the conductive blocks are erased simultaneously, i.e. all written areas are erased simultaneously, and thus the full screen erase becomes faster.

The locking key, the local erasing key and the full erasing key are respectively and electrically connected with the main controller, a user can perform erasing control operation through the three keys, and state modes are configured for the liquid crystal writing device corresponding to the three keys, wherein the state modes comprise a locking mode, a local erasing mode and a full erasing mode. And acquiring the state mode of the liquid crystal writing device according to the key signals generated by the three keys.

The specific working principle and method are as follows: when the local erasing key is in an ON state (namely, enters a local erasing mode), the main controller obtains coordinate information of an erasing position from the infrared touch screen 200, and controls the boosting circuit to respectively output a first erasing voltage signal and a second erasing voltage signal to synapses 1201 of the first erasing conductive layer and external contact points 261-u1, 261-u2, …, 261-u30, 261-d1, 261-d2, … and 261-d30 of the second erasing conductive layer 160 corresponding to the coordinate information to realize local erasing; when the local erasing button is in the OFF state, the local erasing operation cannot be performed. When the full-erase button is in an ON state (i.e., enters a full-erase mode), the main controller controls the voltage boost circuit to output a first erase voltage signal to the synapse 1201 of the first erase conductive layer and a second erase voltage signal to the external contacts 261-u1, 261-u2, …, 261-u30, 261-d1, 261-d2, …, 261-d30 of all the second erase conductive layers 160; when the full-erase button is in the OFF state, the full-erase operation cannot be performed. When the lock button is in an ON state (i.e., enters a lock mode), the main controller sends control signals to the first switch 1821 and the second switch 1822 to keep the first switch 1821 and the second switch 1822 in a normally off state, or the main controller disables the output of the boost circuit through the first control signal line 1824 to shield all erasing operations, and at this time, even if the local erasing button or the full erasing button is touched by mistake, any erasing operation cannot be executed; when the lock button is in the OFF state (i.e., enters the non-lock mode), the main controller may send a control signal to the first switch 1821 and the second switch 1822 to control the closing thereof, or the main controller may unlock the boost circuit through the first control signal line 1824 to allow the boost circuit to output.

The storage module is used for recording and storing the writing track detected by the infrared touch screen 200, so that the writing track can be conveniently checked by a user. The stored content can be transmitted to other electronic equipment in a wired or wireless mode. The wired mode includes two types of USB interfaces and wired network, and the writing and drawing contents can be copied to a USB flash disk by using the USB interface or can be transmitted to other USB equipment connected with the USB flash disk through a USB communication protocol. When the writing device is transmitted by using a wired network, the writing device is connected with a router by using a network adapter; or the writing and drawing contents can be firstly connected to the hub, then connected to the router through the hub, connected to the local area network and the Internet through the router and transmitted to other terminals on the network. The wireless modes include Bluetooth and WIFI. The transmitting object in the Bluetooth mode is required to be provided with a Bluetooth interface, such as a mobile phone; the main controller transmits the content to be transmitted to the Bluetooth module, and the Bluetooth module wirelessly transmits the content to be transmitted to target equipment with a Bluetooth interface according to a Bluetooth communication protocol. Under the WIFI mode, the main controller sends the content to be transmitted to the WIFI module, the WIFI module wirelessly transmits the content to be transmitted to a router with a WIFI interface, the content is transmitted to a network in a wired or wireless mode through the router, and the content is transmitted to a terminal connected with the network through the network.

Optionally, setting an OLED display screen with a size of 5 inches to 15 inches and a driving circuit thereof to display historical writing and drawing information, current writing and drawing information, an operation interface and the like; the display screen can be provided with a capacitive touch screen, so that a user can input information and operation commands conveniently. In addition, the display screen may be an active display screen, a transmissive display screen, or a reflective display screen, such as a PDP, CRT, LCD, electronic ink screen, ChLCD, or the like.

EXAMPLE III

The third embodiment is substantially the same as the second embodiment, and the main differences are that:

first, the infrared touch screen 200 is replaced with a key input device. As shown in fig. 7, the key input device is provided with a key and an indicator light for indicating the state of the key at one side of the writing area corresponding to the row where each conductive block 143 is located, the key is pressed and the indicator light is on, otherwise, the indicator light is off; corresponding to the row of each conductive block 143, a key and an indicator light for indicating the state of the key are arranged on the upper side or the lower side of the writing area, the key is pressed down, the indicator light is on, otherwise, the indicator light is off. And when the row and the column of the position to be erased are seen, the corresponding keys of the row and the column are pressed respectively, and the written content on the position to be erased can be erased.

The key input device is electrically connected to the main controller, the main controller receives key information of the key input device, and the main controller is configured to store a mapping relationship between the key information and the conductive block 143. The key information may be coordinate information of a key position, such as coordinate information of the conductive block 143 corresponding to the key, or the erasing position information is number information of the erasing position, for example, the key is configured to include row keys and column keys, each row key corresponds to a row position of the conductive block 143, each column key corresponds to a column position of the conductive block 143, a combination of the row position and the column position corresponds to the conductive block 143 at the position, the key information is information of the row and column positions where the conductive block 143 at the position to be erased is located, the main controller receives the information of the row and column positions, and erases written content at the position of the conductive block 143 corresponding to the position information.

In other embodiments, the keys are not necessarily mounted at physical positions corresponding to a certain row or a certain column in consideration of convenience of mounting, and the physical positions may be printed with labels corresponding to the rows and columns, and then all the keys may be collectively placed as shown in fig. 8. If the number of the rows and the columns is large, for example, 30 rows and 30 columns, 60 keys are required to be arranged, obviously, too many keys are required, and at this time, the scheme of fig. 9 can be adopted, and the numerical keyboard with 10 number keys is used for inputting the labels of the rows and the columns, so that the simplicity and the rapidness are realized; optional nixie tube 211 may display the number pressed. It can also be implemented with a single key press multiple times, with row 15 pressing 15 and then the ok key, which saves keys.

Second, the display material layer 140 of the first liquid crystal writing layer and the display material layer 140 of the second liquid crystal writing layer are respectively a left-handed cholesteric liquid crystal and a right-handed cholesteric liquid crystal having the same reflection wavelength, so that the reflected light contains both the left-handed light component and the right-handed light component.

Example four

The main difference between this embodiment and the second embodiment is that the scheme for implementing partial erase is different.

As shown in fig. 10, the first erasing conductive layer 120 of the first liquid crystal writing layer and the second liquid crystal writing layer of the present embodiment is provided with a plurality of first conductive strips 121 arranged in parallel and insulated from each other, the second erasing conductive layer 160 is provided with a plurality of second conductive strips 161 arranged in parallel and insulated from each other, and the first conductive strips 121 and the second conductive strips 161 are staggered from each other, so that at least one relatively covered area exists between each first conductive strip 121 and each second conductive strip 161. Preferably, the first conductive strips 121 and the second conductive strips 161 are perpendicular to each other. When at least one first conductive strip 121 is connected to a first erasing voltage signal and at least one second conductive strip 161 is connected to a second erasing voltage signal, an electric field is formed between the first conductive strip 121 and the second conductive strip 161, and the writing trace of the area of the display material layer 140 covered by the electric field is erased.

Specifically, as shown in fig. 11 and 12, the writing area size of the liquid crystal writing panel 100 is 120cmX80cm, the first erasing conductive layer 120 is etched into 80 transverse stripe-shaped conductive areas which are arranged in parallel and insulated from each other to form first conductive strips 121, each first conductive strip 121 has a width of 1cm, and 80X1cm is 80 cm; the second erase conduction layer 160 is etched into 120 parallel longitudinal stripe-shaped conduction regions which are insulated from each other to form second conduction stripes 161, each second conduction stripe 161 is also 1cm wide, and 120X1cm is 120 cm. First conductive strips 121 and second conductive strips 161 are located on first erase conductive layer 120 and second erase conductive layer 160, respectively, and fig. 12 forms an array to show the areas of first conductive strips 121 and second conductive strips 161 that overlap each other. Each of first conductive strips 121 and second conductive strips 161 has an external electrode 263 for connecting with electronic circuit 180. Wherein, the external electrodes of the first conductive strips 121 of the first liquid crystal writing layer are denoted as 263-a1, 263-a2, 263-a3, … …, 263-a 80; the external electrodes of the second conductive strips 161 of the first liquid crystal writing layer are denoted by 263-b1, 263-b2, 263-b3, … … and 263-b 120; the external electrodes of the second conductive strips 161 of the second liquid crystal writing layer are denoted by 263-B1, 263-B2, 263-B3, … … and 263-B120; the external electrodes of the first conductive strips 121 of the second liquid crystal writing layer are denoted by 263-A1, 263-A2, 263-A3, … …, 263-A80.

As shown in fig. 13, the electronic circuit 180 includes an office erasing button, a locking button, a full erasing button, a main controller, a voltage boosting circuit, and a docking circuit. The working principle of the local erasing key, the locking key and the full erasing key is the same as that of the embodiment, and the description is omitted.

Each of the first conductive strips 121 and the second conductive strips 161 is connected to a docking circuit through the external electrode 263, and the docking circuit is used to implement connection between the voltage boosting circuit and the first conductive strips 121 and the second conductive strips 161. The boost circuit outputs a first erase voltage signal and a second erase voltage signal according to a control signal sent by the main controller through a first control signal line 1824. The docking circuit connects the first conductive strip 121 corresponding to the area to be erased with the first erase voltage signal output by the voltage boost circuit and connects the second conductive strip 161 corresponding to the area to be erased with the second erase voltage signal output by the voltage boost circuit according to the control signal sent by the main controller through the third control signal line 1844, so that a voltage difference (specifically, the voltage difference can be realized through a pulse sequence) sufficient for erasing the writing trace is formed between the first conductive strip 121 and the second conductive strip 161 corresponding to the area to be erased, and simultaneously, a voltage difference between the first conductive strip 121 and the second conductive strip 161 corresponding to the non-erased area is insufficient for erasing the writing trace.

The embodiment divides the writing area with the size of 120cmX 3680 cm into 9600 small erasing blocks with the size of 1cmX1cm, so that the small erasing blocks cannot be erased block by block if a user does not observe carefully, and the partial erasing of the liquid crystal writing screen is perfectly realized.

EXAMPLE five

As shown in fig. 14, the liquid crystal writing panel of this embodiment is different from the first embodiment in that the intermediate support layer 170 is a conductive layer to form an intermediate conductive layer, and the intermediate conductive layer plays two roles:

first, as a middle support layer of the two display material layers 140, the cholesteric liquid crystals in the two display material layers are isolated from each other, so that the cholesteric liquid crystals do not permeate each other, and meanwhile, the writing pressure applied to the liquid crystal writing screen is born, and the structural stability of the two display material layers is maintained under the writing pressure. This places certain requirements on the thickness of the intermediate conductive layer, which typically needs to be formed to a thickness of 20 μm to provide support.

Second, the second erase conduction layer is used as the first liquid crystal writing layer and the second erase conduction layer of the second liquid crystal writing layer, that is, the two second erase conduction layers 160 in the first embodiment are combined into one conduction layer (and the non-conductive middle support layer in the first embodiment is omitted, that is, the three layers are integrated). The middle conductive layer, the display material layer 140 and the first erasing conductive layer 120 above the middle conductive layer form a first liquid crystal writing layer, the middle conductive layer, the display material layer 140 and the first erasing conductive layer 120 below the middle conductive layer form a second liquid crystal writing layer, and the middle conductive layer is used as the second erasing conductive layer of the first liquid crystal writing layer and also used as the second erasing conductive layer of the second liquid crystal writing layer. The structure of the middle conducting layer is also the structure of the erasing conducting layer, and the erasing conducting layer can be a complete conducting layer, a conducting block array or a conducting strip as long as the erasing can be realized.

In the above-described embodiment, the erasing conductive layer on one side of each display material layer is implemented as the intermediate conductive layer, and in other embodiments, as shown in fig. 15, when three or more display material layers are provided to form three or more liquid crystal writing layers, the erasing conductive layers on both sides of the display material layer located in the middle are implemented as the intermediate conductive layers, that is, the upper and lower adjacent intermediate conductive layers and the display material layer therebetween form a liquid crystal writing layer, and the erasing conductive layer on one side of the topmost and bottommost display material layers is implemented as the intermediate conductive layer.

What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made, or combinations of the above-described embodiments can be made without departing from the spirit of the invention, and the scope of the invention is to be determined by the appended claims.

Claims

1. A high brightness liquid crystal writing apparatus comprising:

at least two layers of display material (140), the layers of display material (140) comprising cholesteric liquid crystals;

at least one intermediate support layer (170), the intermediate support layer (170) being disposed between each two of the display material layers (140);

erasing conductive layers are respectively arranged on two sides of each display material layer (140), so that the display material layer (140) and the two erasing conductive layers on the two sides of the display material layer form a liquid crystal writing layer, when at least one part of each erasing conductive layer on the two sides of the display material layer (140) is respectively connected with an erasing voltage signal, an electric field is formed between the connected parts of the two erasing conductive layers, and writing traces of the area of the display material layer (140) which is relatively covered are erased;

all the display material layers (140) are the same as left-handed cholesteric liquid crystals with the consistent reflection wavelength or the same as right-handed cholesteric liquid crystals with the consistent reflection wavelength, and a half-wave plate is not arranged between the display material layers (140);

the middle supporting layer (170) is a non-conductive layer, a PET film is adopted, and the thickness is 20-150 mu m;

the erasing conductive layers on two sides of each display material layer (140) are respectively a first erasing conductive layer (120) and a second erasing conductive layer (160), and the display material layer (140), the first erasing conductive layer (120) and the second erasing conductive layer (160) form a liquid crystal writing layer; when at least one part of the first erasing conductive layer (120) is connected with a first erasing voltage signal, and at least one part of the second erasing conductive layer (160) is connected with a second erasing voltage signal, an electric field is formed between the connected part of the first erasing conductive layer (120) and the connected part of the second erasing conductive layer (160), and writing traces of the area of the display material layer (140) which is covered by the electric field are erased.

2. A high brightness liquid crystal writing apparatus according to claim 1, wherein: the middle support layer (170) is a PET film.

3. A high brightness liquid crystal writing apparatus according to claim 1, wherein: the liquid crystal display further comprises a first substrate layer (110) and a second substrate layer (190) which are arranged on two sides of the liquid crystal writing layer and the middle supporting layer (170).

4. A high brightness liquid crystal writing apparatus according to claim 3, wherein: the erasing conductive layers are correspondingly formed on the surfaces of the first base material layer (110), the middle supporting layer (170) and the second base material layer (190).

5. A high brightness liquid crystal writing apparatus according to claim 1, wherein: an insulating layer is further arranged between the first erasing conductive layer (120) and/or the second erasing conductive layer (160) and the display material layer (140).

6. The high brightness liquid crystal writing apparatus of claim 5, wherein:

the insulating layer comprises any one of polyimide, polyimide acid or polyvinyl alcohol, and a liquid crystal alignment layer is formed through rubbing alignment;

or, the insulating layer comprises a first insulating sub-layer and a second insulating sub-layer which are laminated; the first insulating sublayer comprises any one or more of silicon dioxide, gelatin, polyvinyl acetate and polyurethane three-proofing paint; coating a second insulating sublayer on the first insulating sublayer; the second insulating sublayer comprises polyimide that is rubbed to form a liquid crystal alignment layer.

7. A high brightness liquid crystal writing apparatus according to claim 1, wherein: at least one of the first erasing conductive layer (120) and the second erasing conductive layer (160) of each liquid crystal writing layer is provided with a plurality of conductive blocks (143) which are mutually insulated, so that a conductive block array is formed;

when at least one conductive block (143) is connected with a second erasing voltage signal, and a conductive block (143) or the whole erasing conductive layer of another erasing conductive layer opposite to the conductive block (143) is connected with a first erasing voltage signal, an electric field is formed between the conductive block (143) and the conductive block (143) or the whole erasing conductive layer of the other erasing conductive layer, and a writing trace of an area of the display material layer (140) which is covered by the electric field is erased.

8. A high brightness liquid crystal writing apparatus according to claim 7, wherein: the conductive blocks (143) are square, rectangular, parallelogram or hexagonal blocks of uniform size.

9. A high brightness liquid crystal writing apparatus according to claim 1, wherein: the first erasing conductive layer (120) of each liquid crystal writing layer is provided with a plurality of first conductive strips (121) which are arranged in parallel and are mutually insulated, the second erasing conductive layer (160) of each liquid crystal writing layer is provided with a plurality of second conductive strips (161) which are arranged in parallel and are mutually insulated, and the first conductive strips (121) and the second conductive strips (161) are mutually staggered;

when at least one first conductive strip (121) is connected with a first erasing voltage signal, and at least one second conductive strip (161) is connected with a second erasing voltage signal, an electric field is formed between the first conductive strip (121) and the second conductive strip (161), and writing traces of the area of the display material layer (140) which is covered relatively are erased.

10. The high brightness liquid crystal writing apparatus of claim 9, wherein: the first conductive strip (121) and the second conductive strip (161) are perpendicular to each other.

11. A high brightness liquid crystal writing apparatus according to claim 3, wherein:

the first base material layer (110) is a transparent PET film with a frosted effect;

the middle supporting layer (170) is a transparent PET film without frosting effect;

the second base material layer (190) is a black film without a frosting effect.

12. A high brightness liquid crystal writing apparatus according to claim 1, wherein: the erasing voltage signal is a voltage signal with a fixed voltage value, a periodic voltage pulse signal with consistent amplitude or a voltage pulse signal with incompletely consistent amplitude and time interval.