JP2009069307A - Optical writing type display medium and scanning type optical writing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical writing type display medium capable of generating voltage synchronizing with exposure scanning with a simple construction and to provide a scanning type optical writing device. <P>SOLUTION: The optical writing type display medium 2 is provided with a layered body including a liquid crystal layer and an optical conductive layer, a pair of electrodes provided on both sides of the layered body and an insulating layer provided on at least one electrode of the pair of electrodes and having a plurality of rows of a plurality of aperture patterns each having a plurality of apertures formed in a sub scanning direction as one unit. The scanning type optical writing device is provided with a conveying means relatively conveying the optical writing type display medium 2 in the sub scanning direction, a first power supplying terminal supplying power to an electrode on which the insulating layer of the display medium 2 is not provided, a plurality of second power supplying terminals supplying power to the electrode on which the insulating layer of the display medium 2 is provided via the apertures, a voltage applying means applying voltage having a prescribed potential to the first power supplying terminal and applying voltages having potentials different from each other to the plurality of second power supplying terminals and an exposure means performing exposure scanning in a main scanning direction based on image data. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical writing display medium and a scanning optical writing apparatus.

  From the viewpoint of reducing the environmental burden, a recording element called rewritable (re-recording) type electronic paper and a recording apparatus for recording an image on the recording element have been proposed (for example, see Patent Document 1). .

  The recording element disclosed in Patent Document 1 is an optical writable display medium in which a display layer and a photoconductive layer are arranged between a solid electrode and a plurality of sub-electrodes, and an image is recorded on the recording element. The recording apparatus includes a first light source composed of an LED array or a laser array arranged in a line shape, and a second light source that generates light in a planar shape, and the pulse voltage generated by the voltage generator is a solid electrode. And a pulse voltage generated by the voltage generator after erasing the image recorded on the recording element by moving the second light source relative to the recording element. Is applied between the solid electrode and the sub electrode, and the first light source is scanned relative to the recording element so that light is irradiated to the portion corresponding to the sub electrode to which the pulse voltage is applied. Write an image on the recording element.

According to this configuration, in the recording element portion corresponding to the sub-electrode to which no voltage is applied, writing is not performed even when exposed to external light, so that a clear image without noise can be obtained.
International Publication No. WO 2004/068230 A1 Pamphlet

  An object of the present invention is to provide an optical writable display medium and a scanning optical writing apparatus capable of generating a voltage synchronized with exposure scanning with a simple configuration.

  In order to achieve the above object, an aspect of the present invention provides the following optical writing display medium and scanning optical writing apparatus.

[1] A laminate composed of a laminated liquid crystal layer and a photoconductive layer, a pair of electrodes provided on both sides of the laminate, and a power receiving terminal provided on at least one electrode of the pair of electrodes, One or two or more switches formed in a predetermined direction are provided between the one electrode and the power receiving terminal, and are connected to the one electrode and the power receiving terminal by performing a switching operation by an external stimulus. An optical writable display medium comprising a switch pattern holder having a plurality of switch patterns as a unit.

[2] A laminated body composed of a laminated liquid crystal layer and a photoconductive layer, a pair of electrodes provided on both sides of the laminated body, at least one of which is divided in a predetermined direction, and the plurality of electrodes A power receiving terminal provided on the divided electrode; and the predetermined electrode provided between the plurality of divided electrodes and the power receiving terminal and connected to the divided electrode and the power receiving terminal by performing a switching operation by an external stimulus. An optical writing type display medium comprising: a switch pattern holding body having a plurality of switch patterns each having one or two or more switches formed in a direction as one unit for each divided electrode.

[3] The optical writing type display medium according to [1] or [2], wherein the switch pattern holding body has a plurality of rows of the plurality of switch patterns.

[4] The optical writing type display medium according to [1] or [2], wherein the switch pattern holding body includes a conductive elastic body whose resistance value decreases as a result of pressure as the external stimulus.

[5] The optical writing display medium according to [1] or [2], wherein the switch pattern holding body includes a photoconductor whose resistance value is reduced by light as the external stimulus as the switch.

[6] The optical writing display medium according to [1] or [2], wherein the switch pattern holding body includes a thermal resistor whose resistance value is reduced by heating as the external stimulus.

[7] The optical writing display medium according to [4], [5], or [6], wherein the switch pattern holding body has an opening that limits a portion that receives the external stimulus.

[8] A laminated body composed of laminated liquid crystal layers and photoconductive layers, a pair of electrodes provided on both sides of the laminated body, and a plurality of rows of power receiving terminals provided on at least one electrode of the pair of electrodes And 1 or 2 formed in the sub-scanning direction, which is provided between the one electrode and the plurality of rows of power receiving terminals, and is switched by an external stimulus to connect the one electrode and the power receiving terminal. Conveying means for relatively conveying in the sub-scanning direction an optical writable display medium provided with a switch pattern holder having a plurality of switch patterns each having the above switch as a unit, and the optical writable type A first feeding terminal for feeding power to the electrode on which the switch pattern holding body of the display medium is not provided, and a front electrode on the electrode on which the switch pattern holding body of the optical writing type display medium is provided. A plurality of second power supply terminals that supply power via a switch, and a voltage application that applies a voltage having a predetermined potential to the first power supply terminals and applies voltages having different potentials to the plurality of second power supply terminals. Means, an adding means for adding an external stimulus to the switch pattern so that the voltage applied by the voltage applying means is applied to the electrode through the switch pattern, and the voltage applying means and the adding means. A scanning optical writing apparatus comprising exposure means for performing exposure scanning in the main scanning direction based on image data when the voltage is applied between the pair of electrodes.

[9] The scanning optical writing device according to [8], wherein the voltage application unit includes a voltage generator that generates a DC voltage to be applied to the second power supply terminal.

[10] The scanning optical writing device according to [8], wherein the voltage application unit includes a voltage generation unit that generates an AC voltage applied to the second power supply terminal.

  According to the optical writing type display medium of the first aspect, it is possible to generate a voltage synchronized with the exposure scanning with a simple configuration.

  According to the optical writable display medium according to the second aspect, a high-resolution image can be written.

  According to the optical writable display medium according to the third aspect, voltages having different potentials can be applied.

  According to the optical writing type display medium of the fourth aspect, it is possible to reliably apply the voltage based on the switch pattern by pressurization.

  According to the optical writable display medium of the fifth aspect, it is possible to apply a voltage based on the switch pattern with non-contact light.

  According to the optical writable display medium of the sixth aspect, it is possible to apply a voltage based on the switch pattern by non-contact heating.

  According to the optical writing type display medium of the seventh aspect, it becomes possible to drive with a light source and a heat source which cannot be modulated at high speed, and complicated control becomes unnecessary.

  According to the scanning optical writing apparatus of the eighth aspect, it is possible to generate a voltage synchronized with the exposure scanning with a simple configuration.

  According to the scanning optical writing device of the ninth aspect, a DC voltage can be used for the power source.

  According to the scanning optical writing device of the tenth aspect, an AC voltage can be used for the power source.

[First Embodiment]
FIG. 1 is a perspective view showing a schematic configuration of a writing apparatus according to the first embodiment of the present invention. The writing apparatus 1 is a scanning optical writing apparatus, and includes a substantially rectangular apparatus main body 3 having an insertion port 3g into which the display medium 2 is inserted and a discharge port 3h through which the display medium 2 is discharged. The display medium 2 inserted into the opening 3g is provided with a writing head (to be described later) that scans in the main scanning direction X and the sub-scanning direction Y to write an image.

  The apparatus body 3 has a substantially rectangular shape having an upper surface 3a, a lower surface 3b, and side surfaces 3c to 3f, has the insertion port 3g on the side surface 3c, and has the discharge port 3h on the side surface 3e.

(Display medium)
The display medium 2 has a substantially thin rectangular shape, has a memory property of holding a display image with no power supply, and includes a laminated body composed of a laminated cholesteric liquid crystal or the like and a photoconductive layer, An optical writable display medium having a pair of electrodes provided on both sides and writing an image by applying a voltage between the pair of electrodes and irradiating light. Of the pair of electrodes, the electrode on the back surface 2b side is composed of a plurality of divided electrodes divided in the sub-scanning direction Y. The display medium 2 includes a front writing type in which light is applied to the front surface 2a for displaying an image and a back writing type in which light is applied to the back surface 2b. In the present embodiment, a reverse writing type is used.

(Characteristics of liquid crystal layer)
FIG. 2 is a diagram showing the relationship between the molecular orientation of the cholesteric liquid crystal and the optical characteristics. The planar phase indicated by the cholesteric liquid crystal in the liquid crystal layer divides light incident parallel to the helical axis into right-handed rotation and left-handed rotation, Bragg-reflects the circularly polarized light component that matches the twisted direction of the helix, and transmits the remaining light. Causes a selective reflection phenomenon. The central wavelength λ and the reflection wavelength width Δλ of the reflected light are λ = n · p and Δλ =, where p is the helical pitch, n is the average refractive index in the plane orthogonal to the helical axis, and Δn is the birefringence. The light reflected by the cholesteric liquid crystal layer in the planar phase expressed by Δn · p exhibits a bright color depending on the helical pitch.

  As shown in FIG. 2A, the cholesteric liquid crystal having a positive dielectric anisotropy has a planar phase in which the spiral axis is perpendicular to the cell surface and causes the above-described selective reflection phenomenon with respect to incident light. As shown in (b), the helical axis is substantially parallel to the cell surface and allows the incident light to pass through while being slightly scattered, and the helical structure is unwound as shown in FIG. The director shows three states: a homeotropic phase in which the director is directed in the direction of the electric field and almost completely transmits the incident light.

  Among the above three states, the planar phase and the focal conic phase can exist bistable without an electric field. Therefore, the phase state of the cholesteric liquid crystal is not uniquely determined with respect to the electric field strength applied to the liquid crystal layer. When the planar phase is in the initial state, the planar phase and the focal conic phase are increased as the electric field strength increases. When the focal conic phase is in the initial state, the focal conic phase and the homeotropic phase change in this order as the electric field strength increases.

  On the other hand, when the electric field strength applied to the liquid crystal layer is suddenly reduced to zero, the planar phase and the focal conic phase are maintained as they are, and the homeotropic phase is changed to the planar phase.

  In particular, in a liquid crystal layer having a PNLC (Polymer-Networked Liquid Crystal) structure or a PCLC (Polymer-Dispersed Liquid Crystal) structure in which a polymer is added to the cholesteric liquid crystal (anchoring effect) The bistability of the planar phase and the focal conic phase in the absence of an electric field is improved, and the state immediately after the application of the pulse signal can be maintained for a long time.

  FIG. 3 shows the switching behavior of the liquid crystal layer with respect to the voltage applied between the pair of electrodes (externally applied voltage). The solid line shows the behavior at the time of exposure, and the broken line shows the behavior at the time of non-exposure.

  The threshold voltage of the change from the planar phase to the focal conic phase of the liquid crystal layer during exposure is Vpfe, the threshold voltage of the change from the planar phase to the focal conic phase of the liquid crystal layer during non-exposure is Vpfu, and the focal of the liquid crystal layer during exposure The threshold voltage for the change from the conic phase to the planar phase is Vfpe, and the threshold voltage for the change from the focal conic phase to the planar phase of the liquid crystal layer during non-exposure is Vfpu.

On reset, by applying a voltage VH ₁ for more reset VFPU, cholesteric liquid crystal in the liquid crystal layer becomes planar phase. After that, even if the application of the voltage VH ₁ is stopped, the liquid crystal layer maintains a high reflectance because the planar phase has a memory property.

Next, in writing, more VPFE, but it applies a voltage VH ₂ for following the write Vpfu, until the exposure begins, the planar texture is maintained, showing the selective reflection.

  Thereafter, when exposure is started, the voltage distributed to the liquid crystal layer increases, and the liquid crystal layer changes from the planar phase to the focal conic phase. Thereafter, even after the exposure, the focal conic phase has a memory property, so that the liquid crystal layer retains a low reflectance.

On the other hand, in the portion not subjected to exposure, the planar phase formed by applying the voltage VH ₁ equal to or higher than Vfpu is maintained until the end and continues to exhibit selective reflection.

(Configuration of writing device)
4 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 5 is a plan view of the writing device of FIG. 4 as viewed from below. As shown in FIG. 4, the apparatus main body 3 is provided with a receiving plate 5 for receiving the back surface 2b of the display medium 2 between the insertion port 3g and the discharge port 3h. Transport rollers 4A, 4A, reference power supply terminals 144A, (144B), reset power supply terminal 142, reset light source 6, a pair of reset pressurizers 7A, 7A, a write power supply terminal 143, a write head 8, A pair of writing pressurizers 7B, 7B and a pair of transport rollers 4B, 4B are provided.

  One of the pair of conveying rollers 4A and 4A on the insertion port 3g side is a driving roller driven by a motor (not shown), and the other is a driven roller that rotates according to the driving roller. One of the pair of transport rollers 4B and 4B on the discharge port 3h side is connected to the drive roller of the transport roller 4A by a belt, and the other is a driven roller that rotates according to the drive roller.

  Reference power supply terminals 144 </ b> A and (144 </ b> B) shown in FIG. 4 are in contact with a reference power receiving terminal (to be described later) of the display medium 2 so that a reference voltage is applied.

  The reset power supply terminal 142 shown in FIGS. 4 and 5 is in contact with the reset power receiving terminals 210 </ b> A to 210 </ b> C of the display medium 2 so that a reset voltage is applied.

  The writing power supply terminal 143 shown in FIGS. 4 and 5 is in contact with writing power receiving terminals 211A to 211F (to be described later) of the display medium 2 so that a writing voltage is applied.

  The power supply terminals 144, 142, 143 are formed using a spring material having conductivity such as copper alloy such as phosphor bronze and beryllium copper, and stainless steel, and for example, a bending process is performed on the letter “J”. The bulging point is configured to elastically contact each power receiving terminal of the display medium 2.

  As the reset light source 6, for example, an EL (electroluminescence) panel, a light emitting diode panel in which light emitting diodes are two-dimensionally arranged, or the like can be used.

  The pair of resetting pressurizers 7A and 7A and the pair of writing pressurizers 7B and 7B are formed of an elastic member such as rubber and are pressed in a direction in which they come into contact with each other by a biasing member such as a spring. When the display medium 2 enters between the pair of resetting pressurizers 7A and 7A and between the pair of writing pressurizers 7B and 7B, the axes of the pressurizers 7A and 7B are rotated so as to rotate according to the movement of the display medium 2. It is supported. As shown in FIG. 3, the pair of reset pressurizers 7A are arranged at positions to press the reset power receiving terminals 210A to 210C as external stimuli, and the pair of writing pressurizers 7B are as shown in FIG. The power receiving terminals 211A to 211F for writing are arranged at positions to pressurize.

(Write head)
As shown in FIG. 4, the writing head 8 includes a light emitting element array 80 having a plurality of light emitting elements 80 a arranged one-dimensionally in the main scanning direction X, and a lens provided on the light output side of the light emitting element array 80. And an array 81.

  The light emitting element array 80 can be a light emitting element 80a such as a laser or a light emitting diode. In this embodiment, for example, a light-emitting diode array having a resolution of 1600 dpi is used.

  6A is a diagram illustrating a light output surface of the light emitting element array, and FIGS. 6B and 6C are diagrams illustrating a light output surface of the light emitting element array according to the modification. In the writing head 8 of the present embodiment, as shown in FIG. 6A, the light emitting elements 80a are arranged one-dimensionally in the main scanning direction X, but are arranged two-dimensionally in the main scanning direction X. Also good. As a two-dimensional arrangement, for example, as shown in FIG. Specifically, a plurality (for example, three) may be arranged in a diagonal direction at a predetermined angle, and the diagonal array may be arranged in the main scanning direction X at a predetermined pitch. The intervals d in the main scanning direction X of the light emitting elements 80a shown in FIG. As another example of the two-dimensional arrangement, as shown in FIG. 6C, a relatively short one-dimensional arrangement may be arranged in a plurality of rows and shifted in the sub-scanning direction Y by a minute width. Specifically, a plurality (e.g., 8) are arranged in the main scanning direction X as a set, but the first set and the second set are arranged with a slight shift in the sub-scanning direction Y. Similarly, the second group and the third group are also shifted by a minute width, but the first group and the third group are arranged without any deviation in the sub-scanning direction Y by reversing the direction of deviation. That is, the odd-numbered and even-numbered groups are arranged with a slight deviation in the sub-scanning direction Y, but the even-numbered and odd-numbered groups are arranged without deviation in the sub-scanning direction Y. The intervals d in the main scanning direction X of the light emitting elements 80a shown in FIG. Further, the intervals in the sub-scanning direction Y of the light emitting elements 80a are also equal to d. The arrangement shown in FIG. 6C is a device for preventing the plastic packages that fix and support the light emitting elements 80a in units of 8 from interfering with each other.

(Display medium power receiving terminal)
FIG. 7 is a plan view showing the surface of the display medium. In the display medium 2, two reference power receiving terminals 207A and 207B to which a reference voltage is applied along the sub-scanning direction Y are formed on the left and right side surfaces 2c and 2c ′ of the surface 2a.

  FIG. 8 is a plan view showing the back surface of the display medium. In the display medium 2, three reset power receiving terminals 210A to 210C are formed along the sub-scanning direction Y on one side surface 2c side of the back surface 2b, and six writing power receiving terminals are formed on the other side surface 2c ′ of the back surface 2b. 211A to 211F are formed.

A positive voltage (+ HV ₁ ), 0 V (GND), and a negative voltage (−HV ₁ ) are applied to the reset power receiving terminals 210 </ b> A to 210 </ b> C, respectively.

The power receiving terminals 211A to 211C for writing are for odd-numbered divided electrodes from the exposure scanning start side, and the power receiving terminals 211A to 211C for writing have positive voltages (+ HV ₂ ), 0 V (GND), and negative, respectively. (−HV ₂ ) is applied.

The power receiving terminals 211D to 211F for writing are for even-numbered divided electrodes 201B from the exposure scanning start side, and the power receiving terminals 211D to 211F for writing have positive voltages (+ HV ₂ ), 0 V (GND), A negative voltage (−HV ₂ ) is applied.

  The power receiving terminals 210A, 210C, 211A, 211C, 211D, and 211F to which a high voltage is applied are divided into predetermined lengths to prevent electric shock.

(Layer structure of display medium)
9A is a diagram showing a layer structure of the display medium 2, and is a cross-sectional view taken along the line BB in FIG. 8, and FIG. 9B is a cross-sectional view of the main part of FIG. 9A. FIG. 10 is an exploded perspective view of the display medium 2.

  The display medium 2 includes transparent first and second substrates 200A and 200B made of PET (polyethylene terephthalate) and the like disposed opposite to each other, and ITO (indium tin oxide) inside the first substrate 200A. A transparent whole surface electrode (first electrode) 201A formed from, etc., a plurality of transparent divided electrodes (second electrodes) 201B formed from ITO or the like inside the second substrate 200B, and a whole surface electrode 201A And a liquid crystal layer 202 made of cholesteric liquid crystal whose reflectivity changes according to the applied voltage, and light which is arranged with respect to the liquid crystal layer 202 through the light absorption layer 205 and has a resistance value reduced by light irradiation. An opening pattern holder (switch pattern holder) 208 that holds the conductive layer 204 and an opening pattern (switch pattern) 230 formed of an insulator; A conductive elastic body 209 disposed in the opening 200a of the second substrate 200B, the reference power receiving terminals 207A and 207B shown in FIG. 7 formed on the surface 2a and connected to the entire surface electrode 201A via the through holes 206, Reset power receiving terminals 210A to 210C and 211A to 211F shown in FIG. 8 formed on the back surface 2b of the second substrate 200B, and a writing power receiving terminal shown in FIG. 8 formed on the back surface 2b of the second substrate 200B. 211.

  The photoconductive layer 204 includes a charge transport layer and a pair of charge generation layers stacked on both sides of the charge transport layer. As a result, an AC voltage can be applied to the liquid crystal layer 202, so that the deterioration of the liquid crystal layer 202 can be suppressed, and the drive voltage can be lowered and the display medium 2 can have a long life.

  When the display medium 2 enters between the writing pressurizers 7B and 7B, as shown in FIG. 7B, the conductive elastic body 209 is deformed inward, enters the opening pattern 230, and is written as divided electrodes 201B. The incoming power receiving terminal 211 is in a conductive state. This movement is the same when the display medium 2 enters between the reset pressurizers 7A and 7A.

(Divided electrode)
As shown in FIG. 10, the divided electrode 201 </ b> B is provided on the parallel portion 210 and one side surface 2 c side of the parallel portion 210, and contacts the conductive elastic body 209 through the opening 230 of the opening pattern holder 208 </ b> A. The contact part 222 is connected to the part 220a and the other side surface 2c ′ side of the parallel part 210 via the connection part 221, and the conductive elastic body 209 contacts via the opening pattern 230 of the opening pattern holding bodies 208B and 208C. Is provided.

  The contact part 222 provided on the other side of the parallel part 220 is longer than the contact part 220a provided on one side of the parallel part 220 in order to make the application period of the writing voltage longer than the application time of the reset voltage. The length in the sub-scanning direction Y is increased.

  Further, in the divided electrode 201B, the odd-numbered connection portions 221 are formed short from the right side (exposure scanning start side) in FIG. 10, the even-numbered connection portions 221 are formed long, and the contact portions 222 are arranged in a staggered manner. I try to do it.

(Relationship between opening pattern and divided electrode)
FIG. 11 is a plan view of a principal part showing the relationship between the opening pattern and the divided electrodes as seen from the back side of the display medium.

  The opening pattern holding member 208A includes opening patterns 230A and 230C each including a plurality of (for example, four) short openings 231 in the sub-scanning direction Y and a plurality (for example, two) long openings 232 for each divided electrode 201B. An opening pattern 230A as one unit is formed. When the display medium 2 passes through the reset pressurizer 7A, the conductive elastic body 209 is deformed inward and enters into the short openings 231 and the long openings 232 of the opening patterns 230A to 230C, and the power reception for reset shown in FIG. The terminals 210A to 210C and the contact part 220a of the divided electrode 201B are brought into conduction.

  The opening pattern holders 208B and 208C include opening patterns 230D and 230F each including a plurality of (for example, six) short openings 231 in the sub-scanning direction Y and a plurality of (for example, two) long openings for each divided electrode 201B. An opening pattern 230E having 232 as one unit is formed. When the display medium 2 passes through the writing pressurizer 7B, as shown in FIG. 9B, the conductive elastic body 209 is deformed inward and the short openings 231 and the long openings 232 of the opening patterns 230D to 230F. The power receiving terminals 211A to 211F for writing and the contact portion 222 of the divided electrode 201B are brought into conduction.

  The lengths, pitches, and numbers in the sub-scanning direction Y of the short openings 231 and the long openings 232 constituting the opening patterns 230A to 230F formed in the opening pattern holders 208A to 208C are not limited to those shown in FIG.

  FIG. 12 is a block diagram showing a control system of the writing apparatus according to the first embodiment of the present invention. The writing device 1 includes a control unit 10 that controls the entire writing device 1, a roller driving unit 11 that drives the transport rollers 4 </ b> A and 4 </ b> B by a motor, and a reset light source driving unit 12 that drives a reset light source 6. The power supply terminals 142A to 142C and 143A to 143F are provided between the light emitting element array driving unit 13 that drives each light emitting element 80a of the light emitting element array 80 of the writing head 8 and the entire surface electrode 201A and the divided electrode 201B of the display medium 2. , 144A, 144B, and power receiving terminals 207A, 207B, 210A to 210C, and 211A to 211F, and a voltage application unit 14 for applying voltage, and an image storage unit 15 for storing image data.

The voltage application unit 14 includes a reset voltage generation unit 140 that generates a reset voltage (+ HV ₁ , 0V, −HV ₁ ) in the reset mode, and a write voltage (+ HV ₂ ) in the write mode. , 0 V, −HV ₂ ).

  The control unit 10 includes a CPU, a ROM that stores a program for the CPU, a RAM, and the like, and executes the writing mode after executing the reset mode. In the reset mode, the controller 10 controls the reset voltage generator 140 so as to generate a reset voltage, and controls the reset light source driver 12 so that the reset light source 6 is lit. In the write mode, the controller 10 controls the write voltage generator 141 to generate a write voltage, and drives the light emitting element array so as to scan the light emitting element 80a in the main scanning direction X. The unit 13 is controlled.

(Operation of the first embodiment)
FIG. 13 is a diagram illustrating the voltage waveform applied to the display medium 2 and the timing of light irradiation to the display medium 2. Next, the operation of the writing apparatus 1 according to the first embodiment will be described with reference to FIG.

  When the user inserts the display medium 2 into the insertion port 3g of the apparatus main body 3, a photo sensor (not shown) detects the entry of the display medium 2, and based on this detection, the control unit 10 uses a motor (not shown) by the roller drive unit 11. Drive. The conveyance rollers 4A and 4B are rotated by driving the motor, and the display medium 2 is conveyed in the sub-scanning direction Y. While the display medium 2 is being conveyed in the sub-scanning direction Y, the control unit 10 executes the writing mode after executing the reset mode.

(1) Reset Mode In the reset mode, the control unit 10 generates a reset voltage from the reset voltage generation unit 140 of the voltage application unit 14 and supplies + HV ₁ , 0V, and −HV to the reset power supply terminals 142A to 142C, respectively. ₁ is applied, and 0 V is applied to the reference power supply terminal 144A.

The display medium 2 enters between the reset pressurizers 7A and 7A, and as shown in FIG. 13, the contact portion 220a of the divided voltage 201B comes into contact with the conductive elastic body 209 through the short opening 231 of the opening pattern 230A. In some cases, the divided electrode 201B is electrically connected to the reset power supply terminal 142A via the conductive elastic body 209 and the reset power receiving terminal 210A, and the potential becomes + HV ₁ .

  When the contact portion 220a of the divided electrode 201B comes into contact with the conductive elastic body 209 through the long opening 232 of the opening pattern 230B, the divided electrode 201B is reset via the conductive elastic body 209 and the reset power receiving terminal 210B. It is electrically connected to the power supply terminal 142B, and the potential becomes 0V.

When the contact portion 220a of the divided electrode 201B contacts the conductive elastic body 209 via the short opening 230B of the opening pattern 230C, the divided electrode 201B is reset via the conductive elastic body 209 and the reset power receiving terminal 210C. is electrically connected to the power supply terminal 142C, the potential is -HV _1. Therefore, the voltage waveform shown in FIG. 13 is applied to the divided electrode 201B.

  Subsequently, the control unit 10 causes the reset light source drive unit 12 to generate reset light from the reset light source 6. As shown in FIG. 13, the timing of irradiating the reset light is almost the same as the timing of voltage application. The controller 10 turns off the reset light source 6 after a predetermined time has elapsed.

  When the reset light is applied to the back surface 2b of the display medium 2, the reset light passes through the second substrate 200B and the divided electrode 201B and reaches the photoconductive layer 204. When the photoconductive layer 204 is irradiated with light, the resistance value decreases, and thereby the partial pressure of the liquid crystal layer 202 determined by the impedance ratio with the photoconductive layer 204 increases, and the liquid crystal layer 202 becomes a planar phase. The reflectance increases. In this way, the entire liquid crystal layer 202 of the display medium 2 is initialized as a planar phase.

(2) Write mode The control unit 10 reads the image data from the image storage unit 15, controls the voltage application unit 14 and the light emitting element array drive unit 13 based on the image data, and starts the write mode.

Control unit 10 generates a voltage for writing from the writing voltage generating unit 141, respectively to the write power supply terminal _{143A~143F + HV 2, 0V, -HV} 2, + HV 2, 0V, the -HV ₂ And 0 V is applied to the reference power supply terminal 144B.

  Further, the control unit 10 controls the light emitting element array driving unit 13 to perform lighting control of the light emitting elements 80 a of the light emitting element array 80 of the writing head 8 along the main scanning direction X. The light emitting element array 80 projects image light onto the back surface 2 b of the display medium 2.

The display medium 2 enters between the writing pressurizers 7B and 7B, and as shown in FIG. 13, the contact portion 222 of the divided voltage 201B contacts the conductive elastic body 209 through the short opening 231 of the opening pattern 230D. when the divided electrode 201B is electrically conductive elastic body 209 and the write power receiving terminals 211A, the write power supply terminal via the 211D 143A, is electrically connected to 143E, the potential + HV _2.

  When the contact portion 222 of the divided electrode 201B comes into contact with the conductive elastic body 209 through the long opening 232 of the opening pattern 230E, the divided electrode 201B passes through the conductive elastic body 209 and the write power receiving terminals 211B and 211E. Are electrically connected to the write power supply terminals 143B and 143E, and the potential becomes 0V.

When the contact portion 222 of the divided electrode 201B comes into contact with the conductive elastic body 209 via the short opening 231 of the opening pattern 230F, the divided electrode 201B passes through the conductive elastic body 209 and the write power receiving terminals 211C and 211F. Te write power supply terminal 143C, is electrically connected to 143F, the potential is _{-HV 12.} Therefore, the voltage waveform shown in FIG. 13 is applied to the divided electrode 201B.

  When the image light is projected onto the back surface 2b of the display medium 2 as described above, the image light passes through the second substrate 200B and the divided electrode 201B and reaches the photoconductive layer 204.

  In the photoconductive layer 204, a planar phase that reflects light is maintained in a region irradiated with light, and a region that is not irradiated with light changes from a planar phase to a focal conic phase that transmits light. Therefore, after the writing process is completed, the region irradiated with the light of the liquid crystal layer 202 maintains a planar phase and has a high reflectance, so that the illumination light is reflected and appears white. In the area where the light is not irradiated, the liquid crystal layer 202 changes from the planar phase to the focal conic phase, so that the illumination light passes through the liquid crystal layer 202 and is absorbed by the light absorption layer 205 and appears black. This black and white pattern is seen as an image from the surface 2a side of the display medium 2. This image is held for a long time even after the voltage application between the entire surface electrode 201A and the divided electrode 201B is stopped.

[Second Embodiment]
FIG. 14 is a diagram showing a power receiving terminal provided in the display medium according to the second embodiment of the present invention. In the first embodiment, a voltage generator that generates a DC voltage is used. However, in the present embodiment, a voltage generator that generates an AC voltage is used and formed on the back surface of the display medium 2. The power receiving terminal is changed to an AC voltage, and the others are configured in the same manner as in the first embodiment.

  The display medium 2 has two reset power receiving terminals 210A and 210B formed along the sub-scanning direction Y on one side surface 2c side of the back surface 2b, and four write power receiving terminals on the other side surface 2c ′ of the back surface 2b. 211A, 211B, 211D, 211E are formed.

An AC voltage (HV ₁ ) and 0 V (GND) are applied to the reset power receiving terminals 210A and 210B.

An AC voltage (HV ₂ ) is applied to each of the write power receiving terminals 211A and 211D, and 0V (GND) is applied to each of the write power receiving terminals 211B and 211E.

(Relationship between opening pattern and divided electrode)
FIG. 15 is a plan view of a principal part showing the relationship between the opening pattern and the divided electrodes as viewed from the back side of the display medium.

  In the opening pattern holder 208A, an opening pattern 230A including one long opening 232 and an opening pattern 230B including two short openings 231 are formed in the sub-scanning direction Y for each divided electrode 201B. When the display medium 2 passes through the reset pressurizer 7A, the conductive elastic body 209 is deformed inward and enters into the short openings 231 and the long openings 232 of the opening patterns 230A and 230B, and the reset power receiving terminals and the divided electrodes The contact portion 220a of 201B becomes conductive.

  In the opening pattern holders 208B and 208C, an opening pattern 230D including one long opening 232 and an opening pattern 230E including two short openings 231 are formed in the sub-scanning direction Y for each divided electrode 201B. When the display medium 2 passes through the writing pressurizer 7B, the conductive elastic body 209 is deformed inward and enters into the short openings 231 and the long openings 232 of the opening patterns 230D and 230E. The contact portion 222 of the divided electrode 201B becomes conductive.

  The lengths, pitches, and numbers in the sub-scanning direction Y of the short openings 231 and the long openings 232 constituting the opening patterns 230A, 230B, 230D, and 230E formed in each of the opening pattern holders 208A to 208C are the same as those in FIG. It is not limited to.

  FIG. 16 is a block diagram showing a control system of the writing apparatus according to the second embodiment of the present invention. As in the first embodiment, the writing device 1 according to the present embodiment includes a control unit 10, a roller driving unit 11, a reset light source driving unit 12, a light emitting element array driving unit 13, and an image storage unit 15. However, the voltage application unit 14 is different from that of the first embodiment.

  The voltage application unit 14 according to the present embodiment includes power supply terminals 142A, 142B, 143A, 143B, 143D, 143E, 144A, and 144B and power receiving terminals 207A and 207B between the entire surface electrode 201A and the divided electrode 201B of the display medium 2. , 210A, 210B, 211A, 211B, 211D, and 211E.

The voltage application unit 14 includes a reset voltage generator 140 that generates a reset voltage (AC HV ₁ , 0V) in the reset mode, and a write voltage (AC HV ₂ , 0V in the write mode). )) For generating a write voltage.

(Operation of Second Embodiment)
FIG. 17 is a diagram illustrating the voltage waveform applied to the display medium 2 and the timing of light irradiation to the display medium 2.

(1) Reset Mode In the reset mode, the control unit 10 generates a reset voltage from the reset voltage generation unit 140 of the voltage application unit 14, and supplies the AC voltages HV ₁ and 0V to the reset power supply terminals 142A and 142B, respectively. And 0 V is applied to the reference power supply terminal 144A.

The display medium 2 enters between the reset pressurizers 7A and 7A, and as shown in FIG. 17, the contact portion 220a of the divided voltage 201B comes into contact with the conductive elastic body 209 via the long opening 232 of the opening pattern 230A. In some cases, the divided electrode 201B is electrically connected to the reset power supply terminal 142A via the conductive elastic body 209 and the reset power receiving terminal 210A, and potentials + HV ₁ and -HV ₁ appear alternately.

  When the contact portion 220a of the divided electrode 201B comes into contact with the conductive elastic body 209 through the short opening 231 of the opening pattern 230B, the divided electrode 201B is reset via the conductive elastic body 209 and the reset power receiving terminal 210B. It is electrically connected to the power supply terminal 142B, and the potential becomes 0V.

  Subsequently, the control unit 10 causes the reset light source drive unit 12 to generate reset light from the reset light source 6. The timing of irradiating the reset light is almost the same as the timing of voltage application, as shown in FIG. The controller 10 turns off the reset light source 6 after a predetermined time has elapsed.

  When the reset light is applied to the back surface 2b of the display medium 2, the reset light passes through the second substrate 200B and the divided electrode 201B and reaches the photoconductive layer 204. When the photoconductive layer 204 is irradiated with light, the resistance value decreases, and thereby the partial pressure of the liquid crystal layer 202 determined by the impedance ratio with the photoconductive layer 204 increases, and the liquid crystal layer 202 becomes a planar phase. The reflectance increases. In this way, the entire liquid crystal layer 202 of the display medium 2 is initialized as a planar phase.

(2) Write mode The control unit 10 reads the image data from the image storage unit 15, controls the voltage application unit 14 and the light emitting element array drive unit 13 based on the image data, and starts the write mode.

The controller 10 generates a write voltage from the write voltage generator 141, applies AC HV ₂ to the write power supply terminals 143A and 143D, and applies 0V to the write power supply terminals 143B and 143E, respectively. And 0 V is applied to the reference power supply terminal 144B.

  Further, the control unit 10 controls the light emitting element array driving unit 13 to perform lighting control of the light emitting elements 80 a of the light emitting element array 80 of the writing head 8 along the main scanning direction X. The light emitting element array 80 projects image light onto the back surface 2 b of the display medium 2.

The display medium 2 enters between the writing pressurizers 7B and 7B, and as shown in FIG. 17, the contact portion 222 of the divided voltage 201B contacts the conductive elastic body 209 through the long opening 232 of the opening pattern 230D. In this case, the divided electrode 201B is electrically connected to the write power supply terminals 143A and 143D via the conductive elastic body 209 and the write power receiving terminals 211A and 211D, and the potentials + HV ₂ and -HV ₂ are alternately switched. appear.

  When the contact portion 222 of the divided electrode 201B contacts the conductive elastic body 209 through the short opening 231 of the opening pattern 230E, the divided electrode 201B passes through the conductive elastic body 209 and the write power receiving terminals 211B and 211E. Are electrically connected to the write power supply terminals 143B and 143E, and the potential becomes 0V. Accordingly, the voltage waveform shown in FIG. 16 is applied to the divided electrode 201B.

[Third Embodiment]
FIG. 18 is a cross-sectional view of the main part showing the layer structure of the display medium according to the third embodiment of the present invention. In the first and second embodiments, switching is performed using the opening pattern holding body 208 having the opening pattern 230 and the conductive elastic body 209. However, in this embodiment, the photoconductor and the opening pattern holding are performed. Switching is performed using a body, and the rest is configured in the same manner as in the first embodiment.

  Similar to the first embodiment, the display medium 2 includes the first and second substrates 200A and 200B, the entire surface electrode 201A, the plurality of divided electrodes 201B, the liquid crystal layer 202, the photoconductive layer 204, A light absorbing layer 205, a reference power receiving terminal 207, and a writing power receiving terminal 211 are provided, and further, a photoconductor (switch) 240 disposed in the opening 200a of the second substrate 200B and has a light shielding property. An opening pattern holder (switch pattern holder) 208 formed of a material and having the same opening pattern (switch pattern) 230 as that of the first embodiment is provided.

  The power receiving terminal 211 for writing is made of light-transmitting ITO or the like. The power receiving terminal for reset is configured in the same manner as the power receiving terminal for writing.

  By irradiating the back surface 2b of the display medium 2 from the switch light source 41 as an external stimulus, the light is irradiated to the photoconductor 240 through the opening pattern 230, and the resistance value of the photoconductor 240 is lowered. The divided electrode 201B and the power receiving terminal 211 for writing become conductive, and a pulsed voltage can be applied to the display medium 2 as in the first embodiment.

[Fourth Embodiment]
FIG. 19 is a cross-sectional view of the main part showing the layer structure of the display medium according to the fourth embodiment of the present invention. In the first and second embodiments, switching is performed using the opening pattern holding body 208 having the opening pattern 230 and the conductive elastic body 209. However, in this embodiment, the temperature sensitive resistor and the opening pattern are used. Switching is performed using a holding body, and the rest is configured in the same manner as in the first embodiment.

  Similar to the first embodiment, the display medium 2 includes the first and second substrates 200A and 200B, the entire surface electrode 201A, the plurality of divided electrodes 201B, the liquid crystal layer 202, the photoconductive layer 204, A light absorbing layer 205, a reference power receiving terminal 207, a writing power receiving terminal 211, and a photoconductor 240 disposed in the opening 200a of the second substrate 200B, and a heat insulating material. And an opening pattern holder 208 having the same opening pattern 230 as in the first embodiment.

  The power receiving terminal 211 for writing is formed from copper or the like having high thermal conductivity. The power receiving terminal for reset is configured in the same manner as the power receiving terminal for writing.

  By heating the back surface 2b of the display medium 2 as an external stimulus by the thermal head 42, the heat is applied to the thermal resistor 250 through the opening pattern 230, and the resistance value of the thermal resistor 250 becomes low, and the divided electrode 201B. Then, the power receiving terminal 211 for writing becomes conductive, and a pulse voltage can be applied to the display medium 2 as in the first embodiment.

[Other embodiments]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention, and between the embodiments without departing from the spirit of the present invention. The components can be arbitrarily combined.

  In each of the above embodiments, the display medium 2 is moved with respect to the apparatus main body 3. However, the display medium 2 may be fixed and the writing head 8 may be moved.

  The display medium may be a front writing type. In this case, the light absorption layer 205 is disposed between the photoconductive layer 204 and the back surface 2b, and a separation layer is disposed between the liquid crystal layer 202 and the photoconductive layer 204.

  In each of the above embodiments, the opening pattern is used. However, the conductive elastic body, the photoconductor, and the temperature sensitive resistor that connect the divided electrode and the power receiving terminal by an external stimulus may be formed in the size of the opening. Good.

FIG. 1 is a perspective view showing a schematic configuration of a writing apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the molecular orientation of the cholesteric liquid crystal and the optical characteristics. FIG. 3 is a diagram illustrating the switching behavior of the liquid crystal layer with respect to the voltage applied between the pair of electrodes. FIG. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is a plan view of the writing device of FIG. 4 as viewed from below. FIG. 6A is a diagram illustrating a light output surface of the light emitting element array, and FIGS. 6B and 6C are diagrams illustrating a light output surface of the light emitting element array of the modification. FIG. 7 is a plan view showing the surface of the display medium. FIG. 8 is a plan view showing the back surface of the display medium. 9A is a diagram showing a layer structure of the display medium, and is a cross-sectional view taken along line BB of FIG. 8, and FIG. 9B is a cross-sectional view of a main part of FIG. 9A. FIG. 10 is an exploded perspective view of the display medium. FIG. 11 is a plan view of a principal part showing the relationship between the opening pattern and the divided electrodes as seen from the back side of the display medium. FIG. 12 is a block diagram showing a control system of the writing apparatus according to the embodiment of the present invention. FIG. 13 is a diagram illustrating the voltage waveform applied to the display medium and the timing of light irradiation on the display medium. FIG. 14 is a diagram showing a power receiving terminal provided in the display medium according to the second embodiment of the present invention. FIG. 15 is a plan view of a principal part showing the relationship between the opening pattern and the divided electrodes as viewed from the back side of the display medium. FIG. 16 is a block diagram showing a control system of the writing apparatus according to the second embodiment of the present invention. FIG. 17 is a diagram illustrating a voltage waveform applied to the display medium and timing of light irradiation to the display medium. FIG. 18 is a cross-sectional view of the main part showing the layer structure of the display medium according to the third embodiment of the present invention. FIG. 19 is a cross-sectional view of the main part showing the layer structure of the display medium according to the fourth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Writing device 2 Display medium 2a Front surface 2b Back surface 2c, 2c 'Side surface 3 Main body 3a Upper surface 3b Lower surface 3c-3f Side surface 3g Insertion port 3h Discharge port 4A, 4B Conveyance roller 5 Receiving plate 6 Reset light source 7A Reset pressurizer 7B Pressurizer for writing 8 Writing head 10 Control unit 11 Roller driving unit 12 Reset light source driving unit 13 Light emitting element array driving unit 14 Voltage applying unit 15 Image storage unit 41 Switch light source 42 Thermal head 80 Light emitting element array 80a Light emission Element 81 Lens array 140 Reset voltage generator 141 Write voltage generator 142A to 142C Reset power supply terminals 143A to 143F Write power supply terminals 144A and 144B Reference power supply terminal 200A First substrate 200B Second substrate 200a Opening 201A Whole surface electrode 201B Split electrode 202 Liquid crystal layer 204 Light Layer 205 Light absorption layer 206 Through-holes 207A and 207B Reference power receiving terminals 208A to 208C Opening pattern holder 209 Conductive elastic bodies 210A to 210C Reset power receiving terminals 211A to 211F Power receiving terminals 220 Parallel part 220a Contact part 221 Connection Part 222 contact part 230A-230F opening pattern 240 photoconductor 250 temperature sensitive resistor

Claims (10)

A laminate comprising a laminated liquid crystal layer and a photoconductive layer;
A pair of electrodes provided on both sides of the laminate;
A power receiving terminal provided on at least one of the pair of electrodes;
One or two or more switches formed in a predetermined direction are provided between the one electrode and the power receiving terminal, and are connected to the one electrode and the power receiving terminal by performing a switching operation by an external stimulus. An optical writable display medium comprising a switch pattern holder having a plurality of switch patterns as a unit. A laminate comprising a laminated liquid crystal layer and a photoconductive layer;
A pair of electrodes provided on both sides of the laminate, at least one of which is a plurality of divided electrodes divided in a predetermined direction;
A power receiving terminal provided on the plurality of divided electrodes;
One or two or more switches formed in the predetermined direction are provided between the plurality of divided electrodes and the power receiving terminal, and are switched by an external stimulus to connect the divided electrodes and the power receiving terminal. An optical writable display medium comprising a switch pattern holding body having a plurality of switch patterns as one unit for each divided electrode.   The optical writing type display medium according to claim 1, wherein the switch pattern holding body has a plurality of rows of the plurality of switch patterns.   The optical writing type display medium according to claim 1, wherein the switch pattern holding body includes a conductive elastic body whose resistance value is reduced by pressurization as the external stimulus.   3. The optical writing display medium according to claim 1, wherein the switch pattern holding body has a photoconductor whose resistance value is reduced by light as the external stimulus as the switch. 4.   The optical writing type display medium according to claim 1, wherein the switch pattern holding body includes a thermal resistor whose resistance value is reduced by heating as the external stimulus.   The optical writing type display medium according to claim 4, wherein the switch pattern holding body has an opening for limiting a portion to receive the external stimulus. A laminate composed of a laminated liquid crystal layer and a photoconductive layer, a pair of electrodes provided on both sides of the laminate, and a plurality of rows of power receiving terminals provided on at least one electrode of the pair of electrodes; One or two or more switches formed in the sub-scanning direction, which are provided between one electrode and the plurality of rows of power receiving terminals, and are switched by an external stimulus to connect the one electrode and the power receiving terminal. Conveying means for relatively conveying the optical writing type display medium provided with a switch pattern holder having a plurality of switch patterns each having a plurality of switch patterns in the sub-scanning direction;
A first power supply terminal for supplying power to the electrode on which the switch pattern holder of the optical writing type display medium is not provided;
A plurality of second power supply terminals for supplying power to the electrode on which the switch pattern holding body of the optical writing type display medium is provided via the switch;
Voltage applying means for applying a voltage of a predetermined potential to the first power supply terminal and applying voltages of different potentials to the plurality of second power supply terminals;
An adding means for applying an external stimulus to the switch pattern such that the voltage applied by the voltage applying means is applied to the electrode through the switch pattern;
A scanning optical writing apparatus comprising: an exposure unit that performs exposure scanning in a main scanning direction based on image data when the voltage is applied between the pair of electrodes by the voltage applying unit and the adding unit.   The scanning optical writing apparatus according to claim 8, wherein the voltage application unit includes a voltage generation unit that generates a DC voltage to be applied to the second power supply terminal.   The scanning optical writing apparatus according to claim 8, wherein the voltage application unit includes a voltage generation unit that generates an AC voltage to be applied to the second power supply terminal.

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