JP3993884B2 - Display device and image display method thereof - Google Patents

Description

  The present invention relates to a display device for writing and displaying an image with a heating and discharging type print head on a display medium capable of being repeatedly recorded on which a visible image appears by the action of discharge, and an image display method thereof.

In recent years, with the practical use of high-luminance blue light-emitting diodes, display devices using light-emitting diodes (LEDs) of three primary colors (R, G, B) are becoming widespread for advertising displays installed outdoors. However, a display device using a light-emitting diode can be easily enlarged, but is not suitable for high-definition because the pixels are rough. On the other hand, a display device using a liquid crystal (LCD) with extremely fine pixels can be made highly fine, but is not suitable for an advertisement display installed outdoors because it is difficult to increase the screen size.
Thus, as for the display medium used for the screen of the conventional display device, those suitable for enlargement are not suitable for high-definition, and conversely, those suitable for high-definition are not suitable for enlargement. For this reason, there has been a problem that a large screen and a high-definition have a contradiction.
Further, in a conventional display device, it is necessary to energize to display an image on a screen, whether it is a moving image or a still image. For this reason, even if it is sufficient to display still images while rewriting them sequentially as necessary, there is a problem in terms of power saving that consumes the same power as in the case of displaying moving images.

On the other hand, the present applicant filed (Patent Document 1), “An ion generator selectively irradiates a recording medium rewritable by an electric field to form an electrostatic latent image on the surface of the recording medium. An image forming apparatus formed and selectively displayed is disclosed. "
An application of an electrostatic latent image forming method using an ion irradiation method, which is one form of such a heating and discharging method, is a static image in which a visible image appears inside due to the action of the electric charge of the electrostatic latent image formed on the surface. Since an electrostatic latent image can be directly formed on an electro-development type recording medium by ion irradiation, it can be written in a non-contact manner on an electro-development type recording medium generally called a digital paper. Is an optimal image forming apparatus that can be considered at present.
In FIG. 4 of (Patent Document 1), the ion generator for performing ion irradiation is fixed, and the recording medium is used as printing paper by transporting the recording medium, so this is an image forming apparatus (printer). . However, if rewriting is performed repeatedly with an ion generator without replacing the recording medium (not used as printing paper), this is a kind of display device. As described above, a display device using a recording medium as a display medium for a screen can display a still image while sequentially rewriting it as necessary. It can also be used as an advertising display or the like installed outdoors.
Incidentally, as a digital paper at the present time, a minute ball is color-coded into two colors (for example, black and white), and a twist ball system that displays an arbitrary color by rotating the ball according to the difference in electrical characteristics of each color, a minute ball An electrophoretic system in which fine powders of two colors (for example, black and white) are mixed in, and only one color is floated and displayed depending on the electrical characteristics of the fine powders of each color. There is a liquid crystal system that displays the background color of the part where the shutter is opened.
JP 2003-326756 A

  However, (Patent Document 1) discloses a basic concept of an image forming apparatus compatible with digital paper having an ion generator and an image forming apparatus compatible with plain paper of an electrostatic latent image forming system that does not require an optical system. No specific configuration for use as a display device, an image forming method, a display method, or the like has been disclosed. In particular, there has been a demand for specific studies on a configuration for color display, a display screen switching method, and the like.

  The present invention solves the above-mentioned conventional problems, and it is possible to achieve both a large display screen and a high-definition display screen, which is excellent in practicality and visibility, and does not require energization when displaying a still image. It is an object of the present invention to provide a display device that is excellent in energy saving and an image display method for a display device that is excellent in functionality that can reduce the time required for switching the display screen.

In order to solve the above problems, a display device and an image display method thereof according to the present invention have the following configurations.
The display device according to claim 1 of the present invention includes: (a) a discharge part having a discharge electrode; and heating means having a heat generating part for heating the discharge electrode, wherein the discharge generation part of the discharge electrode The arrangement surface of the driver IC and the arrangement surface of the driver IC for controlling the heat generation of the heat generating part are not on the same plane, and the generation of discharge is controlled by controlling the temperature of each discharge electrode to which a discharge control voltage is applied. It has a configuration including a printing unit equipped with a heat discharge type print head, and (b) a display medium on which a visible image appears by discharge from the heat discharge type print head.
This configuration has the following effects.
(1) Since a printing unit equipped with a heat discharge type print head is provided, an image can be formed and displayed on a display medium such as digital paper on which a visible image appears by discharge.
(2) An image written on a display medium with a heat-discharge type print head can be held without any power consumption as in the case of printing on printing paper, and is excellent in energy saving.
(3) In a heat-discharge type print head, a discharge electrode to which a discharge control voltage (a voltage range in which discharge is not generated only by application due to low voltage but discharge occurs when heated) is applied by a heating means By controlling the heating, thermoelectrons are emitted from the discharge generating portion of the heated discharge electrode , and discharge and light emission occur. In an atmosphere where ions can be generated, the amount of generated ions can be controlled, and electrostatic development can be performed. Recording can be performed on a display medium such as digital paper.
(4) Since the amount of ions generated and the emission intensity associated with the discharge from the heat-discharge type print head can be controlled by the heating control, the area gradation on the display medium is facilitated, and the image quality can be improved.
(5) Even when the heat-discharge type print head is arranged so that the surface of the discharge generating portion of the discharge electrode is substantially parallel to the display medium, the display medium does not interfere with the driver IC or IC cover.
(6) The substrate may be formed in a substantially L shape or a square shape by bending the end surface portion of the substrate toward the surface side of the substrate.

Here, the discharge part of the heat discharge type print head has a ladder shape in which one end of a plurality of discharge electrodes divided into comb teeth is connected by a common electrode, or both ends of a plurality of discharge electrodes are connected by a common electrode. Can be formed. By providing a common electrode in the vicinity of the discharge electrode, the discharge electrode's heat dissipation area is increased and the heat capacity is increased, so that the cooling effect of the discharge electrode and the response to heating stop are improved, and the resistance value is always stable. Since a voltage can be applied, the stability of discharge can be further improved.
In particular, when the width of the common electrode is wider than the width of the discharge electrode, the cooling effect of the discharge electrode that is temporarily heated to 200 to 300 ° C. can be improved and the heat can be prevented. It is possible to quickly stop the discharge in response to this, and to shorten the discharge time interval and switch the presence or absence of the discharge in a short time. In addition, the resistance value of the common electrode can be reduced, and the potential difference generated between the discharge electrodes connected by the common electrode can be suppressed as much as possible. Excellent stability.
Further, a conductive material layer may be formed on at least the surface of the common electrode in the discharge part. As a result, the resistance value of the common electrode can be further reduced, the potential difference generated between the respective discharge electrodes can be reliably reduced, and the discharge stability is excellent. The conductive material layer only needs to have conductivity superior to that of the discharge part, and can be easily formed by screen printing of silver paste or silver plating. By increasing the thickness of the conductive material layer, the resistance value of the common electrode can be reduced, and the discharge stability can be improved.

When the discharge electrode is formed in a comb shape, the discharge electrode can be formed in a substantially rectangular shape, a trapezoidal shape, a shell shape, a semicircular shape, or a combination thereof. Further, the peripheral length of the periphery of the discharge electrode can be increased by dividing a part of the discharge electrode with a slit or the like or by forming an uneven portion on the peripheral edge. Since the discharge electrode has a large amount of discharge from the periphery of the edge, it is possible to increase the amount of discharge from the discharge electrode by increasing the circumference of the periphery of the edge, and to increase the amount of irradiated ions and the emission intensity The discharge control device is excellent in energy saving and efficiency. Moreover, since the voltage applied to the discharge electrode can be set small, the life of the discharge electrode is excellent.
Instead of dividing the end portion of the discharge electrode or forming the uneven portion on the peripheral edge portion, the discharge hole portion may be formed in correspondence with the heating position of the heating element. Thereby, discharge can be generated from the periphery of the edge of the discharge hole portion, and the same effect as dividing the end portion of the discharge electrode can be obtained. The shape of the discharge hole portion can be formed in various shapes such as a substantially circular shape, a substantially elliptical shape, a polygon such as a quadrangle and a hexagon, and a star shape. Further, the number and size of the discharge hole portions per one heating place can be appropriately selected and combined.

As the discharge electrode, a metal such as gold, silver, copper, or aluminum formed by vapor deposition, sputtering, printing, etc., and then etched to form a pattern is suitably used. In addition, a conductive material such as carbon may be used.
Since the discharge control voltage is applied to the discharge electrode and the generation of the discharge can be controlled by heating, it is possible to easily generate the discharge selectively from any discharge electrode by selecting the heating location by the heating means. it can.
The thickness when the discharge electrode is formed of aluminum is preferably 0.1 μm to 100 μm. As the discharge electrode becomes thinner than 0.1 μm, it tends to be affected by wear, and the life of the discharge electrode tends to be shortened. As the discharge electrode becomes thicker than 100 μm, the heat capacity increases and the response to heating on / off decreases. There is a tendency to become easy and neither is preferable.

The discharge electrodes of the discharge unit can be arranged in a plurality of rows in a unit of a plurality of discharge electrodes formed at the same basic pitch. By arranging in a staggered manner so as to interpolate between the basic pitches, the minimum pitch between the discharge electrodes can be made narrower than the basic pitch, and the overall resolution can be improved. Since the basic pitch between the discharge electrodes in each column can be formed widely, processing is easy, the mass productivity is excellent, and the yield can be improved.
When a common electrode for connecting a plurality of discharge electrodes is provided, the common electrode may be independent for each column arranged in parallel, or may be common to a plurality of columns.
In addition, when the entire row of discharge electrodes formed at the basic pitch is inclined, the pitch in the arrangement direction of the discharge electrodes projected on the horizontal plane (pitch at the time of image formation) may be narrower than the basic pitch. In addition, the resolution can be improved by mounting with high density without being restricted in processing.

When an induction electrode is provided that is separated from the discharge electrode and insulated from the discharge electrode, the gap between the discharge electrode and the induction electrode is always kept constant, so a voltage must be applied between the discharge electrode and the induction electrode. Thus, it is possible to efficiently generate a discharge. In addition, by covering the induction electrode with the induction electrode insulating film, the induction electrode can be reliably insulated, and the occurrence of a short circuit can be prevented. As a material for the induction electrode insulating film, glass, ceramic, mica, synthetic resin, or the like can be preferably used, and can be formed by screen printing, vapor deposition, sputtering, or the like.
Also, on the back side of the display medium on which recording is performed by irradiation of ions accompanying discharge from the heat discharge type print head, a ground electrode portion or a positive voltage for applying an electric field between the discharge electrode of the heat discharge type print head and the display medium It is preferable to provide a positive voltage application unit for applying. By providing the ground electrode portion, it is possible to irradiate ions from the discharge generation portion of the discharge electrode of the heat discharge type print head toward the display medium regardless of the presence or absence of the induction electrode. In addition, when irradiating negative ions, by providing a positive voltage application unit, a positive voltage can be applied to the display medium side, and the same effect can be obtained. Thereby, unit dots in the printing unit of the display device can be miniaturized, the irradiation position accuracy can be improved, and high-definition recording can be performed.
In addition, when the induction electrode is not provided, the formation process of the induction electrode and the like can be omitted, and the productivity can be improved, and the discharge control device can be miniaturized and mounted with high density. The resolution can be increased.

Of the discharge part, the vicinity of the heating position by the heat generating part of the heating means becomes the discharge generation part, but it is preferable to cover the discharge part except for the discharge generation part. When the discharge part has a common electrode and a discharge electrode, the coating film is covered on the common electrode and on the discharge electrode excluding the discharge generation part. By forming the coating film excluding the discharge generation portion of the discharge electrode, a step can be formed between the surface of the discharge generation portion and the surface of the coating film. Therefore, it is possible to keep the gap between the discharge generating portion of the discharge generating portion and disposed opposite the display medium such as a discharge electrode of the discharge electrode constant to stabilize the discharge from the discharge generating portion of the discharge electrode be able to. In addition, the display medium can be prevented from coming into contact with the discharge generation portion of the discharge electrode.
More specifically, the coating film has an opening formed in a substantially circular shape, a substantially elliptical shape, a substantially rectangular shape, or the like in a discharge generating portion of the discharge portion (near the heating position by the heat generating portion of the heating means). The opening may be formed independently for each of the plurality of discharge generation portions, or may be formed in a long hole shape so as to extend over the plurality of discharge generation portions.
Coating film is formed of an insulating material, glass, synthetic resin such as aramid or polyimide, ceramics such as SiO _2, is a material such as mica is preferably used. The coating film can be formed by screen printing, vapor deposition, sputtering, or the like.
In addition, when an uneven | corrugated | grooved part is formed in the surface of a coating film, the surface distance of a coating film can be extended and surface resistance can be increased. For this reason, since it is possible to prevent leakage of electricity from the discharge generation portion of the discharge electrode to the surroundings, the adverse effect on the driver IC of the heating means does not occur, and the stability of discharge control can be improved. Moreover, since there is no leakage, the applied voltage applied to the discharge electrode does not decrease, and the discharge is stable and efficient.

According to the heat-discharge type print head, it is possible to form an electrostatic latent image or an image by oxidation-reduction reaction. In addition, according to the light emission of discharge, digital paper using a photochromic compound that forms an image with ultraviolet rays, visible light, or the like can be used as a display medium.
When the display device has either one of the printing unit moving unit that moves the printing unit or the display medium conveyance unit that conveys the display medium, the image is displayed with respect to the display medium by moving the printing unit and the display medium relatively. Can be written.
As the display medium, a medium formed in an endless loop (closed loop) shape or a finite length sheet (open loop) in which both ends of the sheet are connected can be used. When the display medium has a sheet (open loop) shape, the display medium is not limited to a flat shape, and may be arranged in a curved shape. When the display medium is in an endless loop (closed loop) shape, the cylindrical shape can be arranged in various shapes at the beginning.
In addition, when a display medium holding unit for detachably holding the display medium is provided as the display device, a user or the like can easily attach and detach the display medium and replace it, and the maintenance is excellent. Even if the display device is not equipped with a display medium from the beginning, an arbitrary display medium capable of forming an image can be selected by the heating / discharge type print head and can be mounted later. It can be widened and has excellent versatility as a display device.

The heating part of the heating means may be any one that can selectively heat a plurality of discharge electrodes, may be heated in close contact with the discharge electrodes, or may be heated separately from the discharge electrodes.
When the heating means is provided with a heat generating part insulating film that is covered with the heat generating part and is in close contact with the discharge electrode, the heat generating part of the heating means can be formed in close contact with the discharge electrode through the heat generating part insulating film. The unit can be handled integrally, the heat discharge type print head is easy to handle, and the display device is easy to assemble. Further, by covering the heat generating portion insulating film with the heat generating portion of the heating means, the heat generating portion can be brought into close contact with the discharge electrode, power consumption required for image recording can be reduced, and energy saving is excellent.

As a heating means having a heat generating part that is heated in close contact with the discharge electrode, the same configuration as that of a thermal print head used in a conventional thermal facsimile can be suitably used. Specifically, the heat generation of the heating element is controlled by a driver IC electrically connected to the heating unit having the heating element. For example, one that selectively heats an arbitrary portion of one heating element disposed across a plurality of discharge electrodes or a plurality of heating elements that are individually disposed corresponding to a plurality of discharge electrodes are selectively used. Some generate heat.
By electrically connecting the heating elements with electrodes formed in a comb-like or matrix pattern, a portion corresponding to an arbitrary discharge electrode in one heating element or a plurality corresponding to individual discharge electrodes Any of the heating elements can be selectively energized to generate heat.
As the heating element, TaSiO ₂ , RuO ₂ or the like is preferably used.
A heat-generating part insulating film is formed to protect and insulate the heating element and the electrodes connected to the heating element. The material of the heat generating part insulating film is preferably a highly heat conductive material that can efficiently transfer the heat of the heat generating element to the discharge electrode, and SiAl, SiO ₂ , SiC, lead glass, mica, etc. are preferably used. The heat generating portion insulating film is formed by screen printing, vapor deposition, sputtering, or the like.

  When the heat generating portion insulating film is formed of glass, the film thickness is suitably 2 μm to 50 μm, preferably 4 μm to 40 μm. As the thickness of the heat generating part insulating film becomes thinner than 4 μm, the insulating property tends to decrease, and as it becomes thicker than 40 μm, it is necessary to increase the applied voltage applied to the discharge electrode and the amount of heat generated by the heating element. Tends to decrease. Also, heat diffusion tends to occur, and the resolution tends to decrease. In particular, as the thickness of the heat generating part insulating film becomes thinner than 2 μm, the surface of the heating element and the electrode connected to the heating element cannot be reliably covered, and pinholes are likely to be generated and reliability tends to be lacking. As the thickness becomes thicker than 50 μm, the stability of discharge tends to be lowered and the mass productivity tends to be lacking. By setting the film thickness of the heat generating part insulating film to 2 μm to 50 μm, preferably 4 μm to 40 μm, both the insulation and the thermal conductivity can be harmonized and both are excellent and the discharge stability is excellent. In particular, even if pinholes occur after each application, the possibility of pinholes overlapping can be reduced by forming the heat-generating part insulating film by multiple application in multiple steps. In addition, the heat generating part can be insulated, so that the reliability is excellent.

When the above-mentioned induction electrode is formed on the heat generating portion insulating film by being horizontally spaced (offset) from the end (edge) on the heat generating portion side of the discharge electrode, instead of forming the discharge electrode on the heat generating portion insulating film. Alternatively, the induction electrode insulating film covering the induction electrode may be extended to the heat generating portion insulating film, and the discharge electrode may be formed thereon. In addition, the induction electrode can be formed by being laminated on the discharge electrode via an induction electrode insulating film.
A head substrate is formed by forming a discharge part and a heating part of a heating means on a hard substrate such as ceramic. A head IC is electrically connected to a driver IC for controlling heat generation. It is a control device. Since the heating means includes a driver IC that selectively energizes the heating element to control the heat generation of the heating element, the heating of the heating element can be controlled at a low voltage, and the voltage applied to the discharge electrode itself Can be reduced, and the heat discharge type print head can be reduced in size and extended in life. Further, it is excellent in mass productivity and reliability as a display device.

The driver IC is wire-bonded to the lead pattern extending from the heat generating portion with a gold wire, and the connecting portion is sealed with an IC protective resin such as an epoxy resin. The print head is obtained by disposing a printed wiring board having a connector for electrically connecting to the outside together with a discharge control device on a heat sink formed of a material such as aluminum. Since the heat generated in the heat generating part can be quickly absorbed by the heat radiating plate and radiated from the heat radiating plate, the heat generating part can be rapidly cooled. For this reason, the responsiveness of the discharge stop corresponding to a heating stop can be improved. In addition, the driver IC can be protected from heat and has excellent reliability. When irregularities are formed on the surface of the heat sink by grooves or the like, the surface area of the heat sink can be increased, and the efficiency of heat dissipation can be improved.
An IC cover may be provided on the surface of the driver IC to protect the driver IC. Thereby, it is possible to reliably prevent the driver IC and the display medium from coming into contact with each other, and the reliability is excellent.

In addition to forming the discharge generation portion of the discharge electrode on the same plane as the substrate on which the driver IC is disposed, the end surface portion of the substrate substantially orthogonal to the surface of the substrate on which the driver IC is disposed, It can be placed on a raised portion of a mold or the like, an edge of the substrate that forms an obtuse angle with the surface of the substrate, or the like.
When the arrangement of the discharge generation part of the discharge electrode is an end face type in which the discharge generation part of the discharge electrode is arranged on the end face part of the substrate on which the driver IC is arranged, the driver IC and the discharge generation part of the discharge electrode are substantially perpendicular to each other. This is preferable because the display medium can be conveyed in a straight line without interfering with the driver IC. Note that the substrate may be formed in a substantially L shape, a substantially rectangular shape, or the like by bending the end surface portion of the substrate toward the surface side of the substrate.
When the arrangement of the discharge generation part of the discharge electrode is an edge type in which the discharge generation part of the discharge electrode is arranged at the edge of the substrate on which the driver IC is arranged, the discharge electrode is arranged at the edge of the substrate chamfered in an inclined manner By disposing the discharge generation portion , the driver IC and the discharge generation portion of the discharge electrode form an obtuse angle, and the same effect as that of the end face type can be obtained without being bulky in the height direction.
When the arrangement of the discharge generation part of the discharge electrode is a raised type in which the discharge electrode is arranged on the raised surface of the raised part formed on the surface of the substrate on which the driver IC is arranged, the vicinity of the top of the raised part and the driver IC By disposing the discharge generation part of the discharge electrode on the opposite raised surface, the same action as that of the end face type or edge type can be obtained without being bulky in the height direction.

When the heat generating part is arranged away from the discharge electrode, the discharge part and the heating means can be manufactured and assembled separately, so that the manufacturing yield can be improved and easy when trouble occurs. It is possible to disassemble the battery, and it is possible to easily repair or replace a worn electrode (discharge part). In addition, since the heat generating part and the discharge electrode are spaced apart to ensure insulation, there is no need to form a heat generating part insulating film or the like for insulating the heat generating part and the discharge electrode. Reduces head man-hours and excels in mass productivity.
In a heating means having a heat generating part that heats away from the discharge electrode, a method of irradiating laser light, a method of irradiating infrared rays, or the like can be suitably used as the heat generating part.
A second aspect of the present invention is the display device according to the first aspect, wherein the discharge generating portion of the discharge electrode is disposed on an end surface portion of the substrate on which the driver IC is disposed . an end face type positioning the discharge generating portion, edge type positioning the discharge generating portion of the discharge electrode to the edge of the substrate, the discharge of the discharge electrode on the raised surface of the raised portion formed on the surface of the substrate It has the structure which is any one of the protruding type | mold which arrange | positions a generation | occurrence | production part .
With this configuration, in addition to the operation of the first aspect, the following operation is provided.
(1) When the arrangement method of the discharge generation part of the discharge electrode is an end face type in which the discharge generation part of the discharge electrode is arranged on the end face part of the substrate on which the driver IC is arranged, the driver IC and the discharge generation part of the discharge electrode By making substantially a right angle, the display medium can be conveyed linearly without interfering with the driver IC.
(2) When the arrangement of the discharge generation part of the discharge electrode is an edge type in which the discharge generation part of the discharge electrode is arranged at the edge of the substrate on which the driver IC is arranged, the edge of the substrate chamfered in an inclined manner By disposing the discharge generation part of the discharge electrode in the driver electrode and the discharge generation part of the discharge electrode form an obtuse angle, the same action as the end face type can be obtained without being bulky in the height direction.
(3) When the arrangement method of the discharge generation part of the discharge electrode is a raised type in which the discharge generation part of the discharge electrode is arranged on the raised surface of the raised part formed on the surface of the substrate on which the driver IC is arranged By disposing the discharge generating portion of the discharge electrode in the vicinity of the top portion or on the raised surface opposite to the driver IC, the same action as that of the end face type or the edge type can be obtained without being bulky in the height direction.
Here, as a heating means having a heat generating portion that is heated in close contact with the discharge electrode, a configuration similar to that of a thermal print head used in a conventional thermal facsimile can be suitably used.
According to a third aspect of the present invention, the display device according to the first or second aspect has a configuration in which a head substrate having the heat generating portion and the discharge portion is disposed on a heat radiating plate .
With this configuration, in addition to the operation of the first or second aspect, the following operation is provided.
(1) By disposing the heat radiating plate on the head substrate, the heat generated in the heat generating portion can be quickly absorbed by the heat radiating plate and radiated from the heat radiating plate. As a result, the heat generating portion can be rapidly cooled to improve the responsiveness to the heating stop. In addition, the driver IC can be protected from heat and excellent in reliability.

A fourth aspect of the present invention is the display device according to any one of the first to third aspects, wherein the printing unit initializes display contents of the display medium and performs a restoration process. It has the structure provided with.
With this configuration, in addition to the operation of any one of claims 1 to 3 , the following operation is provided.
(1) The display medium can be made blank with the restoring unit of the printing unit, and pre-processing when rewriting the display content of the display medium is easy and excellent in practicality.

As the restoring device, a charging roller, a charging brush, or the like is preferably used. As a result, the surface of the display medium on which a visible image appears due to the action of electric charges inside the device can be uniformly charged to initialize the display medium, and rewriting to the display medium can be repeated.
Instead of providing a restorer, unnecessary recording can be erased by irradiating a display medium on which an image has been formed from a heat discharge type print head with ions having a polarity opposite to that at the time of image formation.

A fifth aspect of the present invention is the display device according to any one of the first to fourth aspects, wherein the display medium is disposed on a surface opposite to a surface facing the heat-discharge type print head. It has a configuration including a ground electrode portion or a positive voltage application portion arranged.
With this configuration, in addition to the operation of any one of claims 1 to 4 , the following operation is provided.
(1) Between the discharge electrode of the heat discharge type print head and the display medium on the surface opposite to the surface of the display medium on which recording is performed by irradiating ions accompanying discharge from the heat discharge type print head (back side of the display medium). By providing a ground electrode part for applying an electric field or a positive voltage application part for applying a positive voltage, it is possible to reliably irradiate ions from the discharge electrode of the heat discharge type print head toward the display medium. In addition, since the ion irradiation position accuracy can be improved, high-definition image display can be performed by miniaturizing unit dots in the display medium.

  Here, when the ground electrode portion and the positive voltage application portion of the display medium are on the display screen side (the surface viewed by a person) of the display device, the ground electrode portion and the positive voltage application portion must be transparent. When the display medium has a liquid crystal shutter function, the ground electrode part and the positive voltage application part can be made transparent to respond to transmitted light instead of reflected light.

A sixth aspect of the present invention is the display device according to any one of the first to fifth aspects, wherein the light source is disposed on either the front side or the back side of the display medium. It has the structure provided with the part.
With this configuration, in addition to the operation of any one of claims 1 to 5 , the following operation is provided.
(1) When the display screen side (the surface viewed by a person) of the display device is on the surface (medium substrate) side of the display medium, the light source unit is disposed on the surface side of the display medium, so You can use it to display images.
(2) The display screen side (the surface viewed by a person) of the display device is the back surface (ground electrode part or positive voltage application part) side of the display medium, and the medium substrate has a liquid crystal shutter function (function to pass / block light). If the light source unit is provided on the surface side of the display medium, it can be used as a backlight, and the brightness of the display screen can be maintained at low power by using the transmitted light from the light source unit even at night. it can.
(3) The display screen side (the surface viewed by a person) of the display device is on the back surface (ground electrode portion or positive voltage application portion) side of the display medium, and the medium substrate has a liquid crystal shutter function (function to pass / block light). If not, by disposing the light source unit on the back side of the display medium, the display screen can be illuminated using the reflected light from the light source unit.

A seventh aspect of the present invention is the display device according to any one of the first to sixth aspects, wherein the display primary colors of the display medium are at least three primary colors (R, G, B) in an additive color mixing method. It has the composition which is.
With this configuration, in addition to the operation of any one of claims 1 to 6 , the following operation is provided.
(1) Since the display primary colors are at least the three primary colors (R, G, B) in the additive color mixture method, the display screen can be colorized by the additive color mixture method using transmitted light.

Here, when the medium substrate of the display medium has a liquid crystal shutter function and the ground electrode part and the positive voltage application part are transparent, it is possible to add using the transmitted light by providing a color filter having colors of the three primary colors. It can cope with colorization of the display screen by the color mixing method.
The display primary colors must be at least the three primary colors in the additive color mixing method, but black or the like may be included as necessary.

The invention according to claim 8 is the display device according to any one of claims 1 to 6 , wherein the display primary color of the display medium is at least the three primary colors (Y, M, C) in the subtractive color mixture method. It has the composition which is.
With this configuration, in addition to the operation of any one of claims 1 to 6 , the following operation is provided.
(1) By adopting a configuration in which the display primary colors are at least the three primary colors (Y, M, C) in the subtractive color mixture method, the display screen can be colorized by the subtractive color mixture method using reflected light.

Here, when the display medium includes a reflective layer having the colors of the three primary colors, reflected light can be used. Irrespective of the presence or absence of the liquid crystal shutter function on the medium substrate of the display medium, the display screen can be colored by subtractive color mixing using reflected light by irradiating light from the medium substrate side.
Since the medium substrate side is the display screen side of the display device (the surface viewed by a person), the ground electrode portion and the positive voltage application portion may be transparent or opaque.
The display primary colors must be at least the three primary colors in the subtractive color mixing method, but black or the like may be included as necessary.

A ninth aspect of the present invention is the display device according to the seventh or eighth aspect , wherein each of the display primary colors is arranged in a striped pattern on the display medium.
With this configuration, in addition to the operation of the seventh or eighth aspect , the following operation is provided.
(1) By disposing each display primary color in a striped pattern, it is possible to easily control the display color (by combining each color) in the display primary color pixel and prevent color misregistration.
Here, one pixel is divided into three, and the three primary colors (R, G, B) in the additive color mixing method or the three primary colors (Y, M, C) in the subtractive color mixing method are arranged in a striped pattern as a display primary color for colorization. Yes.

A tenth aspect of the present invention is the display device according to the ninth aspect , wherein the display medium is at least one of a direction parallel to or orthogonal to a longitudinal direction of the display primaries arranged in a striped pattern. It has the structure provided with the parameter | index arrange | positioned.
With this configuration, in addition to the operation of the ninth aspect , the following operation is provided.
(1) When an indicator is provided in a direction parallel to the longitudinal direction of the display primary color arranged in a striped pattern, the inclination of the stripe pattern of the display primary color can be known by reading the inclination of the indicator, The color shift can be reduced by strictly controlling the display color (by combining each color).
(2) When the indicators are provided in the direction perpendicular to the longitudinal direction of the display primary colors arranged in a striped pattern, the inclination of the tip of each display primary color can be known when serially scanning the heat discharge type print head. The occurrence of color misregistration due to serial scanning can be reduced.
(3) When both the indicator arranged in the direction parallel to the longitudinal direction of the display primary color and the indicator arranged in the direction orthogonal to the longitudinal direction of the display primary color are included, every time the serial scanning of the heat-discharge type print head is performed Control in consideration of the inclination of the stripe pattern of the display primary color can be performed, and the accuracy of preventing color misregistration can be improved.

Here, the index can be provided in a blank portion of the display medium.
Since the scanning of the heating discharge type print head is usually performed along the stripe pattern of the display primary color, the inclination of the index is read by moving the heating discharge type print head in advance prior to the scanning of the heating discharge type print head. For example, control in consideration of the inclination of the stripe pattern of the display primary color is possible at the actual scanning stage.
In order to read the inclination of the index, for example, a reading device such as a scanner may be provided so as to be interlocked with the movement of the heat-discharge type print head.

An eleventh aspect of the present invention is the display device according to any one of the first to sixth aspects, wherein a single color display is performed on the entire surface of the display medium or in units of blocks obtained by dividing the display medium. have.
With this configuration, in addition to the operation of any one of claims 1 to 6 , the following operation is provided.
(1) Instead of using a display color obtained by combining the colors of the display primary color pixels, a single color display (monocolor display) is performed on the entire surface of the display medium or in units of blocks obtained by dividing the display medium. The sharpness of the image can be improved as compared with the display color obtained by combining the colors.

Here, the display medium may perform monochromatic display on the entire surface of the display medium, or may perform monochromatic display of different colors in units of blocks obtained by dividing the display medium. The display color when performing monochromatic display is not limited to the display primary colors (R, G, B) in the additive color mixture method and the display primary colors (Y, M, C) in the subtractive color mixture method, and can be arbitrarily selected. Since the monochrome display includes black (monochrome) display, it can be said that the monochrome display is obtained by replacing the color of the black display with another color.
When performing monochromatic display in units of blocks, the display medium is divided into a plurality of blocks, and arbitrary display colors are assigned in units of blocks. For example, when the entire display medium is divided into three, the display primary colors (R, G, B) in the additive color mixture method, the display primary colors (Y, M, C) in the subtractive color mixture method, etc. are assigned to each block one by one. Monochromatic display can also be performed in units.

A twelfth aspect of the present invention is the display device according to any one of the first to eleventh aspects, wherein the printing unit moving unit moves the printing unit or the display medium conveyance unit conveys the display medium. It has the structure provided with at least any one of these.
With this configuration, in addition to the operation of any one of claims 1 to 11 , the following operation is provided.
(1) When the printing unit moving means is provided, it is possible to write an image at an arbitrary position on a fixed display medium by moving the printing unit.
(2) When the display medium is fixed and the printing unit is moved, the display device requires only a sheet-type display medium having the size of the display screen, so that the display medium can be saved.
(3) When the display medium transporting unit is provided, the image can be written while the display medium is moved, and the area where the new image is formed in the display medium is moved to the display screen to display the image. be able to.
(4) When both the printing unit moving unit and the display medium conveyance unit are provided, the relative conveyance speed can be improved by moving the printing unit and the display medium in the opposite directions, and the time required for image formation can be increased. It can be shortened.
(5) When both the printing unit moving unit and the display medium conveying unit are provided, switching of the image to be conveyed and displayed when the printing unit is moved and the writing of the image to the fixed display medium is completed. It can be performed. In particular, if a display medium formed in an endless loop (closed loop) shape of an infinite length or a finite length sheet (open loop) equal to or larger than the size of the display screen is used, while displaying an image on the display screen, The next image to be displayed can be written in the non-display area of the display medium.

Here, as the printing unit moving means, the same moving means used in the conventional image forming apparatus is preferably used.
When the heat-discharge type print head or the restorer has a width that can correspond to the width of the display medium, the print section moving means scans the print section relative to the display medium in a direction that moves relative to the display medium. Images can be written. When the display screen of the display device is enlarged and the width of the heating / discharge type print head or the restoring device becomes narrower than the width of the display medium, the printing unit moving means can cause the printing unit to perform serial scanning. The problem of the width of the heating / discharge type print head and the restoring device can be solved, and an image can be formed over the entire width of the display medium.
Any display medium transporting unit may be used as long as the display medium can be moved relative to the printing unit. An image can be formed by rotating an endless loop (closed loop) display medium or sliding a finite-length sheet (open loop) display medium.

A thirteenth aspect of the present invention is the display device according to the twelfth aspect , wherein (a) the display medium conveying means rotates at least two rollers and at least one of the rollers. And (b) the display medium is wound around in an endless loop around the roller.
With this configuration, in addition to the operation of the twelfth aspect , the following operation is provided.
(1) Since the display medium transport means includes at least two rollers and a roller driving unit that rotates at least one of the rollers, the display medium conveying means rotates the endless loop-shaped display medium wound around the rollers. The image can be moved by being moved, and the image can be rewritten by the fixed printing unit and the formed image can be moved.
(2) Since the display medium is wound around the roller in an endless loop shape, when the print medium moving means for moving the print section is provided, the display medium is switched to the non-display area of the display medium during image display. Images can be written.

Here, as the display medium transporting means, one that can transport the display medium by an arbitrary amount of movement by rotating a roller by a roller driving unit such as a motor is preferably used. Since the display medium is arranged in an endless loop shape, an image can be written to the display medium on the back side of the display device or inside the ring of the endless loop display medium while an image is displayed on the display device. It can be performed.
Switching of images can be performed, for example, by a timer or in accordance with the end of writing by the heat discharge type print head. When the image is switched by the timer, the image can be automatically switched by setting an image switching interval that is longer than the time required for writing the image by the heat-discharge type print head. When switching the image at the end of writing of the heating and discharging type print head, if the movement of the heating and discharging type print head by the printing unit moving means is monitored, the image is immediately switched at the end of writing of the image. This can be done and the waiting time can be shortened.
The image can be switched by switching the entire display screen at once after the entire image has been written, or every time the heating / discharge type print head writes one or more lines, the portion where the writing has been completed. It is also possible to change the display screen little by little by moving only intermittently.

The image display method of the display device according to claim 14 includes: (a) an image forming step of writing an image for switching on the display medium during image display of the display device according to claim 13 ; and (b). An image switching step of switching between an image being displayed on the display device formed on the display medium and the image for switching.
This configuration has the following effects.
(1) Since there is an image forming step of writing an image for switching on the display medium while the display device is displaying an image, it is possible to write an image on the stopped display medium that is displaying the image.
(2) Since there is an image switching step of switching between the image being displayed on the display device formed on the display medium and the image for switching, the switching image formed in the image forming step of the previous step is displayed on the display screen of the display device. The image can be switched by moving to the side.
(3) By repeatedly performing the image forming process and the image switching process, it is possible to sequentially switch still images. Therefore, even when the display device has a large screen, power saving and quick switching of still images are performed. If it is used instead of a movie sign, a still image of a typical scene can be rewritten and displayed periodically or irregularly.

As described above, according to the display device and the image display method of the present invention, the following advantageous effects can be obtained.
According to invention of Claim 1, it has the following effects.
(1) It is possible to provide a display device excellent in energy saving that can hold an image written on a display medium with a heat-discharge type print head without causing power consumption at all as in the case of printing on a printing paper. it can.
(2) In a heat-discharge type print head, heating control is performed on a discharge electrode to which a discharge control voltage (a voltage range in which discharge does not occur when applied but occurs when heated) is applied by a heating means. As a result, thermoelectrons are emitted from the discharge generation part of the heated discharge electrode , and discharge and light emission occur. In an atmosphere where ions can be generated, the amount of generated ions can be controlled. It is possible to provide a display device excellent in energy saving that can perform recording on a display medium such as the above.
(3) Since the amount of ions generated and emission intensity associated with the discharge from the heat-discharge type print head can be easily controlled by heating control, the area gradation on the display medium can be easily performed, and the image quality of the display medium It is possible to provide a high-quality and highly reliable display device capable of improving the quality.
(4) Even when the heat-discharge type print head is arranged so that the surface of the discharge generating portion of the discharge electrode is substantially parallel to the display medium, the display medium does not interfere with the driver IC or IC cover.
According to invention of Claim 2, in addition to the effect of Claim 1, it has the following effects.
(1) When the arrangement method of the discharge generation part of the discharge electrode is an end face type in which the discharge generation part of the discharge electrode is arranged on the end face part of the substrate on which the driver IC is arranged, the driver IC and the discharge generation part of the discharge electrode By making substantially a right angle, the display medium can be conveyed linearly without interfering with the driver IC.
(2) When the arrangement method of the discharge generation part of the discharge electrode is an edge type in which the discharge generation part of the discharge electrode is arranged at the edge of the substrate on which the driver IC is arranged, the edge of the substrate chamfered in an inclined manner By disposing the discharge generation portion of the discharge electrode in the driver electrode and the discharge generation portion of the discharge electrode form an obtuse angle, the same effect as the end face type can be obtained without being bulky in the height direction.
(3) When the arrangement method of the discharge generation part of the discharge electrode is a raised type in which the discharge generation part of the discharge electrode is arranged on the raised surface of the raised part formed on the surface of the substrate on which the driver IC is arranged By arranging the discharge generating portion of the discharge electrode near the top of the electrode or on the raised surface on the opposite side of the driver IC, the same effect as that of the end face type or edge type can be obtained without being bulky in the height direction.
According to invention of Claim 3 , in addition to the effect of Claim 1 or 2, it has the following effects.
(1) By disposing the heat radiating plate on the head substrate, the heat generated in the heat generating portion can be quickly absorbed by the heat radiating plate and radiated from the heat radiating plate. As a result, the heat generating portion can be rapidly cooled to improve the responsiveness to the heating stop. In addition, the driver IC can be protected from heat and excellent in reliability.

According to invention of Claim 4 , in addition to the effect of any one of Claims 1 thru | or 3 , it has the following effects.
(1) It is possible to provide a display device excellent in practicality in which the display medium can be made blank with the restoring unit of the printing unit, and preprocessing when rewriting the display content of the display medium is easy.

According to invention of Claim 5 , in addition to the effect of any one of Claims 1 thru | or 4 , it has the following effects.
(1) Between the discharge electrode of the heat discharge type print head and the display medium on the surface opposite to the surface of the display medium on which recording is performed by irradiating ions accompanying discharge from the heat discharge type print head (back side of the display medium). By providing a ground electrode part for applying an electric field or a positive voltage application part for applying a positive voltage, it is possible to reliably irradiate ions from the discharge electrode of the heat discharge type print head toward the display medium. In addition, it is possible to provide a high-definition display device capable of improving the ion irradiation position accuracy and miniaturizing unit dots in the display medium.

According to invention of Claim 6 , in addition to the effect of any one of Claims 1 thru | or 5 , it has the following effects.
(1) Practicality of displaying an image using reflected light or transmitted light from the light source unit depending on the type of display medium and whether the display screen side (surface viewed by a person) is the front or back of the display medium It is possible to provide an excellent display device.

According to invention of Claim 7 , in addition to the effect of any one of Claims 1 thru | or 6 , it has the following effects.
(1) Providing a display device with excellent functionality capable of coping with colorization of a display screen by an additive color mixing method using transmitted light because the display primary color is at least the three primary colors (R, G, B) in the additive color mixture method can do.

According to invention of Claim 8 , in addition to the effect of any one of Claims 1 thru | or 6 , it has the following effects.
(1) The display primary color is at least the three primary colors (Y, M, C) in the subtractive color mixture method, and the display has excellent functionality that can cope with the colorization of the display screen by the subtractive color mixture method using reflected light. An apparatus can be provided.

According to invention of Claim 9 , in addition to the effect of Claim 7 or 8 , it has the following effects.
(1) By disposing each display primary color in a striped pattern, it is easy to control the display color (by combining each color) in the display primary color pixels, and display with excellent reliability and practicality that can prevent color misregistration. An apparatus can be provided.

According to the invention described in claim 10 , in addition to the effect of claim 9 , the following effect is obtained.
(1) The inclination of the stripe pattern of the display primary color can be known from an index provided in the direction parallel to the longitudinal direction of the display primary color arranged in a striped pattern, and the display color (by combining each color) of the display primary color pixel It is possible to provide a display device with excellent reliability and practicality capable of reducing color misregistration by strictly controlling.
(2) It is possible to know the inclination of the tip of each display primary color by an index provided in the direction perpendicular to the longitudinal direction of the display primary colors arranged in a striped pattern, and the occurrence of color misregistration due to serial scanning of the heat discharge type print head. It is possible to provide a display device with excellent reliability and practicality that can be reduced.
(3) When both the indicator arranged in the direction parallel to the longitudinal direction of the display primary color and the indicator arranged in the direction orthogonal to the longitudinal direction of the display primary color are included, every time the serial scanning of the heat discharge type print head is performed. It is possible to provide a display device with excellent reliability and functionality that can perform control in consideration of the inclination of the stripe pattern of the display primary color and can improve the accuracy of color misregistration prevention.

According to the invention described in claim 11 , in addition to the effect of any one of claims 1 to 6 , the following effect is obtained.
(1) By performing single color display (monocolor display) on the entire surface of the display medium or in units of blocks obtained by dividing the display medium, the display color can be compared with the display colors obtained by combining the colors in the display primary color pixels of the additive color mixture method and subtractive color mixture method. A display device with a clear image and excellent visibility can be provided.

According to invention of Claim 12 , in addition to the effect of any one of Claims 1 to 11 , it has the following effects.
(1) Practicality that the display medium can be moved relatively by driving at least one of the printing unit moving means and the display medium conveying means, and the image can be written on the display medium; A display device with excellent functionality can be provided.
(2) A display medium formed with an endless loop (closed loop) having an infinite length or a sheet (open loop) having a finite length equal to or larger than the size of the display screen when both the printing unit moving unit and the display medium conveying unit are provided. By using the, the image to be displayed next can be written in the non-display area of the display medium by moving the printing unit while the image is displayed on the display screen, and the display medium can be changed after the writing is completed. It is possible to provide a display device excellent in practicality and functionality that can be moved to switch images.

According to the invention described in claim 13 , in addition to the effect of claim 12 , the following effect is obtained.
(1) Since the display medium transport means can move the endless loop-shaped display medium, the switching image can be written in the non-display area of the display medium that is displaying the image, and the image writing is completed. At that time, it is possible to provide a display device excellent in practicality and versatility that can display a switching image by transporting the display medium.

According to the invention of the fourteenth aspect , the following effects can be obtained.
(1) By repeating the image forming process and the display medium moving process, it is possible to sequentially switch still images. Therefore, even if the display device has a large screen, power saving and quick switching of still images are possible. An image display method of a display device with excellent practicality and functionality that can be used to replace and display a still image of a representative scene periodically or irregularly if used instead of a movie signboard. Can be provided.

FIG. 3 is a main part schematic diagram illustrating a structure of a display device in Embodiment 1; (A) Schematic side view showing a heat discharge type print head of a display device in Embodiment 1 (b) A schematic perspective view of a main part showing a heat discharge type print head of a display device in Embodiment 1. FIG. 3 is a plan development view of a main part of a head substrate of a heat discharge type print head of the display device in the first embodiment. (A) AA sectional view taken along the line AA in FIG. 3 (b) A sectional view taken along the line B-B in FIG. 3. FIG. 3 is an exploded perspective view of the main part of the head substrate of the heat discharge type print head of the display device in the first embodiment. FIG. 3 is a configuration diagram of a discharge control device for a heat discharge type print head of the display device in the first embodiment. FIG. 5 is a perspective view showing a heating part forming step of the head substrate of the heat discharge type print head of the display device in the first embodiment. FIG. 6 is a perspective view showing a discharge part forming step of the head substrate of the heat discharge type print head of the display device in the first embodiment. FIG. 3 is a schematic cross-sectional view showing a main part of the display device in the first embodiment. (A) Main part schematic exploded view showing the configuration of one pixel of the display medium of the display device in the first embodiment (b) Plane perspective view showing the arrangement of display primary colors and indices of the display medium of the display device in the first embodiment It is. FIG. 10 is a schematic exploded view of a main part of one pixel showing a first modification of the display medium of the display device in the first embodiment. 10 is a schematic plan view illustrating a second modification of the display medium of the display device in Embodiment 1. FIG. FIG. 10 is a schematic rear view of a main part showing a modification of the display device in the first embodiment. (A) Schematic cross-sectional view of relevant parts showing a display device in a second embodiment (b) A schematic exploded view of relevant parts showing a configuration of one pixel of a display medium of a display device in a second embodiment. FIG. 10 is a schematic cross-sectional view showing a main part of a display device in a third embodiment. FIG. 10 is a schematic cross-sectional view showing a main part of a display device in a fourth embodiment. FIG. 10 is a schematic cross-sectional view of a relevant part showing a modification of the display device in the fourth embodiment.

Explanation of symbols

1, 1a, 1b, 1c, 1d, 1e Display device 2 Printing unit 3 Heating discharge type print head 4 Restorer 5, 5a, 5b, 5c Display medium 6 Medium substrate 6a Medium substrate surface 6b Medium substrate body 6c Color filter 6d Reflection Layer 7, 7b Ground electrode portion 7a Ground electrode portion surface 8a, 8b Index 10 Heat sink 11 Substrate 11a End surface portion 12 Head substrate 13 Discharge portion 13a Discharge electrode 13b Common electrode 14 Driver IC
DESCRIPTION OF SYMBOLS 15 Discharge control apparatus 16 Printed wiring board 17 Connector 18 IC cover 18a High voltage board 19 Heating common conductor pattern 19a Heating comb-tooth electrode 19b Heating common electrode 20 Heating individual electrode 20a Bonding pad 21 Heating part 21a Heating element 21b Heating part Insulating film 22 Discharge generating unit 23 Heating means 24a, 24b Light source unit 25a, 25b Roller 26 Control unit

(Embodiment 1)
A display device and an image display method thereof according to Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a main part schematic diagram showing the configuration of the display device in the first embodiment.
In FIG. 1, 1 is a display device according to Embodiment 1 of the present invention, 2 is a printing unit of the display device 1, 3 is a heat-discharge type print head of the printing unit 2, and 4 is a medium substrate 6 of the display medium 5 described later. A restorer 5 for the printing unit 2 that uniformly charges the medium substrate surface 6a, a display medium 5 for a display device 1 such as a digital paper on which a visible image appears due to the action of electric charges generated by the discharge of the heat-discharge type print head 3, Is disposed on the back side of the display medium 5 (the surface opposite to the surface facing the heating / discharge type print head 3), and is a ground electrode portion for applying an electric field between the heating / discharge type print head 3 and the display medium 5; This is the surface of the ground electrode part.

The heat discharge type print head 3 forms an image by moving relative to the display medium 5. However, if the display medium 5 is in the form of a finite length sheet (open loop), the heat discharge type print head 3 and the restoration are used. It is preferable to move the display medium 4 if the display medium 4 is moved and the display medium 4 is in an endless loop (closed loop) of infinite length. Although FIG. 1 shows the case where the display medium 5 has a sheet (open loop) shape and the heating / discharge type print head 3 moves, an image is formed on the display medium 5 even when the display medium 5 is moved. The principle to do is the same.
Depending on the polarity of the applied voltage, the heating / discharge type print head 3 can irradiate either positive or negative ions during discharge, but here, writing is performed from the medium substrate surface 6a side of the display medium 5 by negative ion irradiation. Will be described.
According to the heat-discharge type print head 3, it is possible to form an image by oxidation-reduction reaction in addition to the formation of the electrostatic latent image. In addition, light emission accompanying discharge can be recorded on digital paper using a photochromic compound that forms an image with ultraviolet rays or visible rays.

Next, a procedure for rewriting an image written on the display medium 5 will be described.
First, the restorer 4 of the printing unit 2 uniformly charges the surface of the display medium 5 with a polarity opposite to that at the time of image writing. As a result, it is possible to perform a restoration process that erases and initializes all the display contents of the display medium 5 (returns to a blank sheet state). As the restoring device 4, a charging roller, a charging brush, or the like is preferably used.
Next, when ion irradiation is performed by the heating / discharging type print head 3, a visible image appears on the display medium 5 due to the action of electric charges.
In order to apply an electric field to the display medium 5 in connection with the heat-discharge type print head 3, a ground electrode portion 7 is provided on the back surface side of the display medium 5 (the side opposite to the image writing side). It is considered that applying an electric field promotes the action due to the electric charge, and a visible image can be surely appeared on the display medium 5 by using the energy of the electric charge in the portion where the electric field of the display medium 5 is applied.

As described above, it is necessary to restore the display medium 5 as a pre-processing when rewriting the display contents of the display medium 5. However, instead of using the restorer 4, the heating / discharge type print head 3 can be used for image formation. The display medium 5 may be traced by irradiating positive ions with the opposite polarity. Thereby, the image being displayed on the display medium 5 can be blanked (initialized) and erased.
In addition, as a measure for preventing misalignment when the heat discharge type print head 3 is used for tracing, a reverse polarity is applied to an area wider than the area of the image once written, for example, an extended tracing area widened by a certain width. You can trace it.

Next, details of the heat-discharge type print head will be described.
FIG. 2A is a schematic side view showing a heat discharge type print head of the display device in the first embodiment, and FIG. 2B is a main part showing the heat discharge type print head of the display device in the first embodiment. It is a model perspective view.
In FIG. 2, 10 is a heat radiating plate of the heat-discharge type print head 3 formed of a material such as aluminum, and 12 is a heat radiating plate and a discharge portion 13 which are laminated on a substrate 11 made of ceramic or the like. The head substrate of the heat-discharge type print head 3, 13 a is a plurality of discharge electrodes of the discharge unit 13 formed in a comb shape, 13 b is a common electrode of the discharge unit 13 connecting one end of the discharge electrode 13 a, and 15 is the head substrate. 12 is a discharge control device for the heat discharge type print head 3 provided with a driver IC 14, 16 is a printed wiring board provided on the heat sink 10 with a connector 17 for electrical connection to the outside, 18 is a driver IC 14 and An IC cover 18a, which is provided to protect the printed wiring board 16, is disposed on the back surface of the IC cover 18, and is connected to the common electrode 13b of the discharge unit 13 by electric wiring (not shown). A voltage board for supplying a high voltage to the discharge electrode 13a is.

Next, details of the structure of the head substrate will be described.
3 is a plan development view of a main part of the head substrate of the heat-discharge type print head of the display device according to the first embodiment, and FIG. 4 (a) is a cross-sectional view taken along the line AA in FIG. FIG. 5B is a cross-sectional view taken along the line B-B in FIG. 3, and FIG. 5 is an exploded perspective view of the main part of the head substrate of the heat discharge type print head of the display device in the first embodiment.
3 to 5, reference numeral 19 denotes a heat generating common conductor pattern formed on the upper surface of the substrate 11 connected to the plurality of heat generating comb-tooth electrodes 19a, and 19b denotes heat generated on the upper surface of the heat generating common conductor pattern 19. Common electrode, 20 is a heating individual electrode formed on the upper surface of the substrate 11 alternately with the heating comb electrode 19a, 20a is a bonding pad formed at the end of the heating individual electrode 20, and 21 is a discharge control device. 15 is a heat generating element of the heat generating part 21 formed by being electrically connected to the upper portion of the heat generating comb-tooth electrode 19a and the heat generating individual electrode 20, and 21b is a heat generating common electrode 19b and a heat generating individual electrode 20. A heat generating portion insulating film 22 covered on the upper surface of the substrate 11 except for the end portion of the substrate is a discharge generating portion of the discharge electrode 13a that generates a discharge when heated by the heat generating element 21a.
The above-described discharge part 13 is insulated from the heat generating element 21a by the heat generating part insulating film 21b, and a plurality of discharge electrodes 13a are formed opposite to the heat generating element 21a corresponding to the positions of the individual electrodes 20 for heat generation.

Next, the configuration of the discharge control device will be described in detail.
FIG. 6 is a configuration diagram of a discharge control device for the heat discharge type print head of the display device according to the first embodiment.
In FIG. 6, the head substrate 12 has a discharge part 13 and a heat generating part 21. The heating means 23 controls the heat generation of the heat generating element 21a of the heat generating portion 21 by the driver IC 14 electrically connected to the heat generating portion 21. It is the discharge control device 15 of the heat discharge type print head 3 that controls the discharge from the discharge generation part 22 of the discharge electrode 13 a by controlling the heating of the discharge part 13 to the discharge electrode 13 a by the heating means 23.
In addition, by disposing the heat radiating plate 10 on the head substrate 12, the heat generated in the heat generating portion 21 can be quickly absorbed by the heat radiating plate 10 and radiated from the heat radiating plate 10. Thereby, rapid cooling of the heat generating part 21 is enabled, and the responsiveness with respect to a heating stop is improved. Further, the driver IC 14 and the like can be protected from heat and excellent in reliability. When irregularities are formed on the surface of the heat radiating plate 10 by grooves or the like, the surface area of the heat radiating plate 10 can be increased, and the efficiency of heat radiation can be improved.

Next, a method for manufacturing the head substrate will be described in detail.
FIG. 7 is a perspective view showing a heat generating portion forming process of the head substrate of the heat discharge type print head of the display device in the first embodiment, and FIG. 8 is a head substrate of the heat discharge type print head of the display device in the first embodiment. It is a perspective view which shows the discharge part formation process of this.
First, the heating part forming step will be described.
In FIG. 7, after a conductor such as a gold paste is printed on the surface of a substrate 11 formed of a ceramic or the like into a long plate shape, a plurality of heating comb electrodes 19a connected by a heating common conductor pattern 19 by etching. And the individual electrode 20 for heat_generation | fever is formed. Thereafter, a belt-like heating element 21a is formed by printing TaSiO ₂ , RuO ₂ or the like on the heating comb electrode 19 a and the heating individual electrode 20. Further, the heat generating common electrode 19b is formed on the upper surface of the heat generating common conductor pattern 19 by printing silver paste or the like.

Bonding pads 20 a were formed at the ends of the individual heating electrodes 20. Thereby, connection with the driver IC 14 by wire bonding can be easily performed.
The heating unit 23 preferably has the same configuration as a thermal print head used in a conventional thermal facsimile. In this case, the manufacturing process of the existing thermal print head can be followed, and the discharge control device 15 can be manufactured at low cost by using the manufacturing device.
In the present embodiment, the heating element 21a of the heating part 21 is formed in a band shape, the heating comb-tooth electrodes 19a and the heating individual electrodes 20 are alternately arranged, and one heating individual electrode 20 at each center and By energizing between the heat generating comb electrodes 19a on both sides, an arbitrary portion of the heat generating element 21a corresponding to the position of the discharge generating portion 22 of each discharge electrode 13a is selectively heated, and the discharge electrode 13a is However, the present invention is not limited to this, and any structure that can selectively heat the discharge generating portion 22 of each discharge electrode 13a may be used. In addition to the heating means 23 that heats the heat generating part 21 by insulating and closely contacting the discharge electrode 13a, a heating means that uses a laser, infrared rays, or the like that is heated away from the discharge electrode 13a as the heat generating part 21 can also be used. .

Next, the discharge part forming process will be described.
In FIG. 8, the heat generating portion insulating film 21b is formed by printing an insulator such as glass, ceramic, mica, or synthetic resin on the surface of the substrate 11 except for the end portions of the heat generating common electrode 19b and the heat generating individual electrode 20. Form. The heat generating part insulating film 21b may be any film that can protect and insulate the heat generating common electrode 19b, the heat generating individual electrode 20, the heat generating element 21a, etc., but efficiently transfer the heat of the heat generating element 21a to the discharge electrode 13a. High thermal conductivity materials such as SiAl, SiO ₂ , SiC, polyimide, and aramid that can be used are preferably used.
The optimum film thickness of the heat generating portion insulating film 21b depends on the material, but when it is formed of glass, it is formed to 4 μm to 40 μm. As the film thickness of the heat generating part insulating film 21b becomes thinner than 4 μm, the insulation tends to be lowered. As the film thickness becomes larger than 40 μm, it is necessary to increase the applied voltage applied to the discharge part 13 and the heat generation amount of the heat generating element 21a. This is because it has been found that there is a tendency that the energy saving property tends to be lowered. By setting the film thickness of the heat generating portion insulating film 21b to 4 μm to 40 μm, the insulation and thermal conductivity can be harmonized and both are excellent and the discharge stability is excellent.
In addition, when the printing of the heat generating portion insulating film 21b is performed in a plurality of times, even if pinholes are generated by each coating, the possibility of pinholes overlapping can be reduced, and heat generation is reliably performed. Since the part 21 can be insulated, it is excellent in reliability.

Next, a plurality of discharge electrodes 13a facing the heat generating individual electrodes 20 of the heating means 23 and a common electrode 13b connecting them are formed on the heat generating portion insulating film 21b. For forming the discharge electrode 13a and the common electrode 13b, a metal such as gold, silver, copper, or aluminum formed by vapor deposition, sputtering or printing and then etched to form a pattern is suitably used. In addition, a conductive material such as carbon may be used.
Although the discharge electrode 13a is formed in a substantially rectangular shape in the present embodiment, it can be formed in a trapezoidal shape, a shell shape, a semicircular shape, or a combination thereof. Further, since the discharge generating portion 22 of the discharge electrode 13a has a large amount of discharge from the periphery of the edge, a plurality of uneven portions may be formed on the outer peripheral edge of the discharge electrode 13a so that the peripheral length of the periphery of the edge becomes long. The amount of ion irradiation can be increased by increasing the amount of discharge from the discharge generator 22, and the discharge controller 15 is excellent in energy saving and efficiency. Moreover, since the voltage applied to the discharge electrode 13a can be set small, the long life of the discharge electrode 13a is also excellent.

Of the discharge part 13, the vicinity of the heating position by the heat generating part 21 of the heating means 23 becomes the discharge generation part 22, but the discharge part 13 may be covered with a coating film except for the discharge generation part 22. By forming the coating film excluding the discharge generation part 22 of the discharge electrode 13a, a step can be formed between the surface of the discharge generation part 22 and the surface of the coating film. Therefore, since the gap between the display medium 5 which is opposed to the discharge generating portion 22 of the discharge electrode 13a can be kept constant, the discharge from the discharge generating portion 22 of the discharge electrode 13a can be stabilized. In addition, the display medium 5 can be prevented from coming into contact with the discharge generating portion 22 of the discharge electrode 13a, and the reliability is excellent.

The end face type heat discharge type print head 3 shown in FIG. 2 is characterized in that the discharge generating portion 22 of the discharge electrode 13a is located on the end face portion 11a of the substrate 11 on which the driver IC 14 is disposed. Even when the heat-discharge type print head 3 is arranged so that the surface of the discharge generating portion 22 of the discharge electrode 13a is substantially parallel to the display medium 5, the display medium 5 and the driver IC 14 or IC cover 18 do not interfere with each other. Since an image can be written in a state orthogonal to the display medium 5, it can be said that it has an optimum shape for use in the display device 1.
Further, when the heating discharge type print head 3 is scanned to form an image, the heating discharge type print head 3 and the high voltage substrate 18a can be moved together, so that it is difficult to apply a load to the electric wiring and the conduction failure. Generation can be reduced.
In the present embodiment, the substrate 11 is formed in a flat plate shape. However, the substrate 11 is formed in a substantially L shape or a square shape by bending the end surface portion 11a of the substrate 11 to the surface side of the substrate 11 or the like. Also good. Further, the arrangement of the discharge generation part 22 of the discharge electrode 13a may be an edge type in which the discharge generation part 22 of the discharge electrode 13a is arranged at the edge of the substrate 11 on which the driver IC 14 is arranged. Since the discharge generation part 22 of the discharge electrode 13a is arranged at the edge of the substrate 11 that is chamfered in an inclined manner, the manufacture is easy and the productivity is excellent, and the driver IC 14 and the discharge generation part 22 of the discharge electrode 13a form an obtuse angle. Therefore, the same action as that of the end face type can be obtained without being bulky in the height direction.

Next, details of the display device will be described.
FIG. 9 is a schematic cross-sectional view of a main part showing the display device in the first embodiment.
In FIG. 9, 24 a is a light source unit disposed on the medium substrate 6 side of the display medium 5, and 24 b is a light source unit disposed on the ground electrode unit 7 side of the display medium 5.
The display device 1 shown in FIG. 9 has a configuration in which an image is formed on the display medium 5 by fixing the sheet type display medium 5 and moving the printing unit 2. When the display medium 5 is fixed as described above, a display medium transport unit for transporting the display medium 5 is not required, and the display device 1 can be downsized, and a display having a size approximately equal to the display screen of the display device 1 can be achieved. Images can be written using the entire medium 5 effectively without waste, and the display medium 5 can be saved.
In the display device 1, since the ground electrode portion 7 of the display medium 5 is on the display screen side (a surface viewed by a person) of the display device 1, the ground electrode portion 7 must be transparent. As will be described later, when the medium substrate 6 has a liquid crystal shutter function (function of passing / blocking light), the light source unit 24a is placed behind the display screen of the display medium 5 (medium substrate 6 side) as indicated by a solid line. When installed and used as a backlight, the brightness of the display screen can be maintained with low power consumption by using the transmitted light from the light source unit 24a even at night. When the display medium 5 does not have a liquid crystal shutter function, the light source unit 24b is installed on the display screen side (ground electrode unit 7 side) of the display medium 5 as shown by a broken line, and reflection from the light source unit 24b. The display screen can be illuminated using light.
In addition, since the printing unit 2 is arranged on the back side of the display screen of the display device 1 (the side opposite to the surface seen by a person), the printing unit 2 can be hidden inside the display device 1 so that it cannot be seen from the outside. The appearance of the display device 1 can be improved.

Next, details of the display medium will be described.
First, the configuration of the pixels of the display medium will be described.
FIG. 10A is a main part schematic exploded view showing the configuration of one pixel of the display medium of the display device in the first embodiment.
In FIG. 10A, 6b is a substrate body of a medium substrate 6 having a liquid crystal shutter function, and 6c is a striped pattern of three primary colors (R, G, B) in an additive color mixing method as a display primary color by dividing one pixel into three. This is a color filter of the arranged medium substrate 6. The ground electrode portion 7 is transparent.
Since the ground electrode part 7 is transparent, the liquid crystal shutter function of the substrate body 6b can be utilized to control the passage and blocking of light in the entire display medium 5. This is the same as the colorization method of the liquid crystal, and a desired color can be displayed using the transmitted light from the light source unit 24a in units of pixels.
When transmitted light is used, at least the three primary colors in the additive color mixing method are necessary as display primary colors, but black or the like may be included as necessary. Of course, if the color becomes four colors, the pixels on the medium substrate 6 are divided into four and correspond to the color filters on which the four display primary colors are arranged.
In the present embodiment, the display primary colors are arranged in a striped pattern to facilitate control of the display colors (by combining the colors) in the display primary color pixels and prevent color misregistration. This arrangement is not limited to this, and other arrangement methods such as a staggered pattern may be used.

Next, the arrangement of display primary colors and indices on the display medium will be described.
FIG. 10B is a perspective plan view showing the arrangement of display primary colors and indices on the display medium of the display device in the first exemplary embodiment.
In FIG. 10B, 8a and 8b are arranged in the marginal part of the substrate surface 6a of the substrate body 6b in the display medium 5 in the direction parallel to the longitudinal direction of the display primary color of the color filter 6c and in the direction orthogonal to the longitudinal direction of the display primary color, respectively. This is an index for alignment of the provided heat discharge type print head 3.
Here, the three primary colors (R, G, B) in the additive color mixing method are taken up as display primary colors. However, in the case of four primary colors including black, the three primary colors (Y, M, C) in the subtractive color mixing method are used. In the case of the above, the arrangement of the indicators 8a and 8b is the same.
The reason why the indicator 8a is provided along the stripe pattern of the display primary color in the margin of the substrate surface 6a of the display medium 5 is to know the inclination of the stripe pattern of the display primary color by reading the inclination of the indicator 8a. In order to read the inclination of the index 8a, for example, a scanner may be provided so as to be interlocked with the movement of the heat discharge type print head 3.

The scanning of the heat-discharge type print head 3 for writing an image on the display medium 5 is usually performed along a stripe pattern of display primary colors. Prior to the scanning of the heating / discharge type print head 3, if the inclination of the index 8a is read by moving the heating / discharge type print head 3 in advance, control in consideration of the inclination of the stripe pattern of the display primary color is performed at the actual scanning stage. It becomes possible. Since the display color (by combining each color) can be strictly controlled in the display primary pixel, color shift can be prevented as much as possible.
By providing the index 8b orthogonal to the stripe pattern of the display primary colors, the inclination of the tip of each display primary color can be corrected when the heating / discharge type print head 3 is serially scanned.
By providing both the indicators 8a and 8b, it is possible to perform control in consideration of the inclination of the stripe pattern of the display primary color for each serial scanning of the heating and discharging type print head 3, and to improve the accuracy of preventing color misregistration. Can do.

Next, a modification of the display medium will be described.
FIG. 11 is a schematic exploded view of a main part of one pixel showing a first modification of the display medium of the display device in the first embodiment.
The display medium 5a of the first modified example in FIG. 11 is different from that of the first embodiment in that the medium substrate 6 is not provided with a liquid crystal shutter function (function of passing / blocking light) and the medium substrate 6 has one. One pixel is divided into three, and the three primary colors (Y, M, C) in the subtractive color mixing method are arranged in a striped pattern as display primary colors. The ground electrode portion 7 may be transparent or opaque as in the first embodiment.
The display medium 5a displays the color of the entire display medium 5a using the reflected light of the medium substrate 6. The display primary colors (Y, M, C) of the medium substrate 6 are formed by, for example, a twist ball capsule or an electrophoretic capsule having the colors of the three primary colors. And the desired color using the reflected light from the light source part 24b is displayed per pixel.

When using reflected light, at least the three primary colors in the subtractive color mixing method are necessary as the display primary color, but black or the like may be included as necessary. Of course, if the color becomes four colors, the pixels on the medium substrate 6 are divided into four to correspond to the medium substrate on which the four display primary colors are arranged.
If the resolution of the heat discharge type print head 3 is coarser than the size of one color pixel such as a twist ball capsule or an electrophoretic capsule having the colors of the three primary colors, the resolution and display of the heat discharge type print head 3 are displayed. A plurality of twist ball capsules, electrophoretic capsules, or the like may be arranged per pixel so that the size of the pixel of the medium 5a matches.

FIG. 12 is a schematic plan view showing a second modification of the display medium of the display device in the first embodiment.
The display medium 5b of the second modified example in FIG. 12 is different from the first modified example in that the entire display medium 5b is divided into three blocks instead of using the display color by combining the colors of the display primary color pixels. As shown by hatching, different display colors for monochromatic display (monocolor display) are assigned to the entire pixels of each block. Black display (monochrome display) is a kind of monochromatic display, and it can be said that the monochromatic display is obtained by replacing the black of the black display (monochrome display) with another color.
By making the entire pixel a single color display, the sharpness can be improved as compared with the display color obtained by combining the colors of the display primary color pixels.
In FIG. 12, the display medium 5b is divided into three blocks and different display colors are arranged for each block. However, the number of divisions of the display medium 5b and the display color displayed in each divided block are arbitrarily selected. Can do. For example, each block unit is assigned the same display color (Y, M, C) as the display primary color in the subtractive color mixture method, or the same display color (R, G, B) as the display primary color in the additive color mixture method. Mono-color display can also be performed in block units. Moreover, you may make it perform the monochromatic display by the same display color on the display medium 5b whole surface.

Next, a modification of the display device will be described.
FIG. 13 is a schematic rear view of a main part showing a modification of the display device in the first embodiment.
The display device 1a of the modified example in FIG. 13 is different from the first embodiment in that it includes two printing units 2.
By providing the two printing units 2, writing can be performed in parallel by the plurality of heat-discharge type print heads 3, and the writing speed of the image on the display medium 5 can be improved.
The time required to rewrite the display screen of the display device 1a can be shortened, and the still image switching time can be shortened.
Also, one of the heat discharge type print heads 3 can be used for writing an image, and the other type of heat discharge type print head 3 can be used for erasing an image. In that case, the restorer 4 can be dispensed with.

As described above, the display device according to Embodiment 1 has the following operations.
(1) Since the print unit 2 includes the heat-discharge type print head 3, an image can be recorded on a display medium 5 such as digital paper on which a visible image appears due to the action of discharge.
(2) The image written on the display medium 5 by the heat-discharge type print head 3 can be held without any power consumption as in the case of printing on the printing paper, and is excellent in energy saving.
(3) In the heat-discharge type print head 3, the heating means 23 heats the discharge electrode 13 a to which a discharge control voltage (which means a voltage range in which discharge does not occur but is generated by heating) is applied. By controlling, thermoelectrons are emitted from the discharge generation part 22 of the heated discharge electrode 13a , and discharge and light emission occur. In an atmosphere where ions can be generated, the amount of generated ions can be controlled. Recording can be performed on a display medium 5 such as a developing type digital paper.
(4) Since the amount of ions generated and the light emission intensity associated with the discharge from the heating / discharge type print head 3 can be controlled by the heating control, the area gradation on the display medium 5 is facilitated and the image quality can be improved. .
(5) Since the heating means 23 includes the heat generating part 21 having the heat generating element 21a and the driver IC 14 for controlling the heat generation of the heat generating element 21a, the heat generating element 21a that generates heat by controlling the heat generation of the heat generating element 21a with a low voltage is provided. Corresponding discharge electrodes 13a can be heated, and image recording is easily controlled and practical.
(6) Since the heat generating portion 21 of the heating means 23 is in close contact with the discharge electrode 13a via the heat generating portion insulating film 21b, the heating means 23 and the discharge portion 13 can be handled integrally, and the heat discharge type print head 3 Is easy to handle, and the assembly workability of the display device 1 is excellent.
(7) Since the heat generating part insulating film 21b is covered with the heat generating part 21 of the heating means 23, the heat generating part 21 can be brought into close contact with the discharge electrode 13a, and the power consumption required for image recording can be reduced, thereby saving energy. Excellent.
(8) Since the heating means 23 is provided, it is possible to discharge by applying a discharge control voltage to the discharge unit 13 at all times and applying a low heat generation temperature of the heat generating element 21a to the discharge electrode 13a, thereby saving energy during image formation. Excellent in properties.
(9) By having the high voltage substrate 18a electrically connected to the discharge part 13, the electrical wiring for applying the discharge control voltage can be shortened, and the reliability can be improved. In particular, when an image is formed by scanning the heat-discharge type print head 3, the heat-discharge type print head 3 and the high-voltage board 18a can be moved together, so that it is difficult for a load to be applied to the electric wiring, resulting in poor conduction. Generation can be reduced.
(10) The high-voltage board 18a can be handled integrally with the heat-discharge type print head 3, and since it is not necessary to handle the electrical wiring, it can be easily incorporated into the display device 1 and has excellent mass productivity.
(11) The restorer 4 of the printing unit 2 can make the display medium 5 blank, and the preprocessing when rewriting the display content of the display medium 5 is easy and has excellent practicality.
(12) Since the ground electrode portion 7 on the back side of the display medium 5 on the image writing side is made transparent, the ground electrode portion 7 side can be made the front side of the display screen. It can be hidden inside the display device 1 so that it cannot be seen from, and is excellent in functionality and practicality.
(13) Since the display medium 5 is fixed and the heat-discharge type print head 3 is moved to write an image on the display medium 5, only the display medium 5 having the size of the display screen is required, and the entire display device 1 is also downsized. It is excellent in productivity and space saving.
(14) When the substrate body 6b of the display medium 5 has a liquid crystal shutter function and the ground electrode portion 7 is transparent, the transmitted light can be used with the light source portion 24a provided in the display device 1 as a backlight.
(15) When the substrate body 6b of the display medium 5 has a liquid crystal shutter function and the ground electrode portion 7 is transparent, the display medium 5 includes a color filter 6c having at least three primary colors (R, G, B) in the additive color mixing method. Accordingly, it is possible to cope with colorization of the display screen by an additive color mixing method using transmitted light.
(16) When the color filter 6c in which one pixel is divided into three and the display primaries are arranged in a striped pattern, the display color (by combining each color) in the display primaries can be easily controlled and the color shift can be reduced. A high-quality display screen can be obtained.
(17) By having the index 8a disposed in the direction parallel to the longitudinal direction of the display primary color of the color filter 6c and the index 8b disposed in the direction orthogonal to the longitudinal direction of the display primary color, the heat discharge type print head can be easily provided. 3 can be aligned and the coloration of each display primary color can be strictly controlled, so that the accuracy of preventing color misregistration can be improved and the reliability is excellent.
(18) When the display medium 5a that does not have the liquid crystal shutter function is used, reflected light from the light source unit 24b can be used.
(19) In the case of the display medium 5a that does not have the liquid crystal shutter function, the display primary color is at least the three primary colors (Y, M, C) in the subtractive color mixture method, thereby displaying by the subtractive color mixture method using reflected light. It can correspond to the colorization of the screen.
(20) When the display medium 5b capable of monochromatic display in each divided block unit is used, monocolor display is possible in each divided block unit.
(21) When the printing unit 2 includes a plurality of heating / discharging printheads 3, each heating / discharging printhead 3 can write an image on the display medium 5 in parallel, and rewrites the display screen. Can be shortened.

(Embodiment 2)
A display device according to Embodiment 2 of the present invention will be described below with reference to the drawings.
FIG. 14A is a schematic cross-sectional view of a main part showing the display device in the second embodiment.
In FIG. 14A, the display device 1b according to the second embodiment of the present invention is different from the first embodiment in that the printing unit 2 is opposite the display screen side outside the display medium 5c formed in an endless loop shape. The display medium 5c is wound around the rollers 25a and 25b of the display medium transporting means and is rotatably disposed on the side (the back side of the display device 1b).
In addition, a roller driving unit (not shown) of a display medium transport unit for rotating the rollers 25a and 25b is connected to one of the rollers 25a and 25b.

The printing unit 2 is fixed so as to face the substrate surface 6a of the medium substrate 6, but the display medium 5c is moved by the rollers 25a and 25b of the display medium conveying means to write the image and to form the formed image. Can be moved and displayed on the display screen side.
By disposing the display medium 5c in an endless loop shape, the ground electrode portion 7b is disposed inside the ring of the display medium 5c (the side positioned on the back side of the display screen), so that the medium substrate 6 side is the display screen side of the display device 1b. The ground electrode portion 7b may be opaque because it becomes (a surface seen by a person).
Since light is not transmitted if the ground electrode portion 7b is opaque, the light source portion 24a is installed on the display screen side of the display medium 4 (the front side of the display device 1b), and incident light from the light source portion 24a is reflected by the medium substrate 4a. The display screen may be illuminated with reflected light.

Next, details of the display medium will be described.
Figure 14 (b) is a main part schematic exploded diagram showing a configuration of a pixel of a display medium of the display device in the second embodiment.
In FIG. 14B, the display medium 5c of the display device in the second embodiment is different from the display medium 5 of the display device in the first embodiment in that the medium substrate 6 has one pixel instead of the color filter 6c. This is the point that a reflective layer 6d is provided in which the three primary colors (Y, M, C) in the subtractive color mixing method are arranged in a striped pattern as display primary colors.

Although the substrate main body 6b of the display medium 5c has a liquid crystal shutter function (function to pass / block light), since the ground electrode portion 7b is opaque, the passage / blocking of light in the entire display medium 5c cannot be controlled. . Therefore, the display screen is on the substrate surface 6a side of the same medium substrate 6 as the image writing side. Since the liquid crystal shutter function of the substrate body 6b can be utilized in the display medium 5c, the color of the entire display medium 5c is displayed using the reflected light of the medium substrate 6.
The light incident on the medium substrate 6 from the light source unit 24a is reflected inside the substrate body 6b when the shutter of the substrate body 6b is closed, and displays white, and when the shutter is opened, the light behind the substrate body 6b is displayed. The color of the reflected light reflected by the reflective layer 6d is displayed. Since the medium substrate 6 includes the reflective layer (background color) 6d having the colors of the three primary colors in units of pixels, a desired color using reflected light from the light source unit 24a can be displayed in units of pixels.
The display primary colors must be at least the three primary colors in the subtractive color mixing method, but black or the like may be included as necessary. Of course, if the four colors are used, the pixels on the medium substrate 6 are divided into four to correspond to the reflective layers of the four display primary colors.

As described above, the display device according to the second embodiment has the following operation in addition to the first embodiment.
(1) By arranging the display medium 5c in an endless loop shape, the ground electrode portion 7b side is arranged inside the ring of the display medium 5c (the side located on the back side of the display screen), and outside the ring of the display medium 5c (image) Since the display medium 5c can be written from the surface exposed on the display screen side during display), the transparency of the ground electrode portion 7b is not necessarily required, and the selection range of the material of the ground electrode portion 7b can be widened. Excellent design flexibility and productivity.
(2) Since the medium substrate 6 includes the reflective layer 6d in which one pixel is divided into three and the three primary colors (Y, M, C) in the subtractive color mixing method are arranged as a display primary color in a striped pattern, the reflected light is used. The display screen can be colorized by the subtractive color mixing method.
(3) An image can be written while the display medium 5c is moved by the rollers 25a and 25b of the display medium conveying means, and an area where a new image (switching image) is formed in the display medium 5c. The image can be displayed by moving to the display screen.

(Embodiment 3)
A display device according to Embodiment 3 of the present invention will be described below with reference to the drawings.
FIG. 15 is a schematic cross-sectional view of a main part showing the display device in the third embodiment.
In FIG. 15, the display device 1c according to the third embodiment of the present invention differs from the second embodiment in that the printing unit 2 and the light source unit 24a are fixed inside the ring of the display medium 5 formed in an endless loop shape. And the medium substrate 6 side of the display medium 5 is disposed inside the ring, and the ground electrode portion 7 side is disposed outside the ring.
Note that the configuration of the display medium 5 is the same as that of the first embodiment and is as shown in FIG.
Since the ground electrode portion 7 is transparent and the medium substrate 6 also has a liquid crystal shutter function, the light source portion 24a is installed inside the ring of the endless loop-shaped display medium 5c together with the printing portion 2, and transmitted light from the light source portion 24a Just illuminate the display screen.

As described above, the display device according to the third embodiment has the following operation in addition to the first or second embodiment.
(1) Since the printing unit 2 and the light source unit 24a can be installed inside the ring of the endless loop-shaped display medium 5c, the display device 1c can be made compact, and the display device 1c has no irregularities and is easy to handle. Excellent installation flexibility.

(Embodiment 4)
A display device according to Embodiment 4 of the present invention will be described below with reference to the drawings.
FIG. 16 is a schematic cross-sectional view of a main part showing the display device in the fourth embodiment.
In FIG. 16, the display device 1d according to the fourth embodiment of the present invention differs from the second embodiment in that the printing unit 2 is arranged so as to be rotatable with respect to the display medium 5c by a printing unit moving means (not shown). It is a point that has been established. Reference numeral 26 denotes a control unit of the display device 1d.
The configuration of the display medium 5c is the same as that of the second embodiment and is as shown in FIG.

Since the printing unit 2 is movable with respect to the display medium 5c, the control unit 26 moves the printing unit 2 on the back side of the display device 1d while displaying an image on the display screen side of the display device 1d. It is possible to write a switching image to be displayed next by the heating / discharge type print head 3.
After the image writing by the heating / discharge type print head 3 is completed, the control unit 26 rotates the rollers 25a and 25b of the display medium conveying means to move the area where the image for switching the display medium 5c is formed to the display screen side. The image can be switched.
The image can be switched by a timer of the control unit 26 or in accordance with the end of writing of the heating / discharge type print head 3. When the image is switched by the timer, the image can be automatically switched by setting an image switching interval that is longer than the time required for writing the image by the heat-discharge type print head 3.
When the image is switched in accordance with the end of writing of the heating / discharge type print head 3, the image can be switched immediately at the end of the image writing, and the waiting time can be shortened.
Note that the image switching can be performed so that the entire image is switched at once after the writing of the entire image for switching is completed, and writing is performed each time the heating / discharge type print head 3 performs writing of one line or plural lines. It is also possible to change the image little by little by intermittently moving only the finished part to the display screen side.

An image display method of the display device 1d according to Embodiment 4 of the present invention configured as described above will be described.
First, in the image forming process, the image for switching is written by the heat-discharge type print head 3 while moving the printing unit 2 during the image display of the display device 1d. If an image has already been formed on the display medium 5c, the image for switching is written after initialization by the decompressor 4.
When the printing unit 2 is moved in the direction of the arrow shown by the broken line in FIG. 16, the image for switching can be written by the heating and discharging type print head 3 following the initialization by the restoring unit 4. The printing unit 2 can move in the direction opposite to the direction of the arrow shown by the broken line, and at that time, the image can be written by the heating / discharge type print head 3 and can be initialized by the restoring unit 4.
Next, in the image switching step, one of the rollers 25a and 25b is rotated by a roller driving unit (not shown) of the display medium transport means, and the display medium 5c is transported in the direction of the arrow indicated by the solid line. The image being displayed on the display device 1d and the image for switching formed in the previous image forming process are switched.
By repeatedly performing the image forming process and the image switching process by the control unit 26, it is possible to sequentially switch the still image and display the image on the display device 1d.

Next, a modification of the display device will be described.
FIG. 17 is a schematic cross-sectional view of an essential part showing a modification of the display device in the fourth embodiment.
In FIG. 17, the display device 1e according to the fourth embodiment of the present invention differs from the fourth embodiment in that the printing unit 2 and the light source unit 24a are fixed inside the ring of the display medium 5 formed in an endless loop shape. And the medium substrate 6 side of the display medium 5 is disposed inside the ring, and the ground electrode portion 7 side is disposed outside the ring.
Note that the configuration of the display medium 5 is the same as that of the first embodiment and is as shown in FIG.
Further, since the image display method of the display device 1e is the same as that of the fourth embodiment, detailed description thereof is omitted.
The control unit 26 can also be disposed inside the ring of the display medium 5 together with the printing unit 2 and the light source unit 24a, and the display device 1e can be made compact.

When the heat-discharge type print head 3 and the restoring device 4 have a width that can correspond to the width of the display media 5 and 5c, scanning is performed only in the direction of the arrow that moves the print unit 2 relative to the display media 5 and 5c. It is possible to write an image on the display media 5 and 5c simply by making them. When the display screens of the display devices 1d and 1e are enlarged, when the width of the heat-discharge type print head 3 or the restoring device 4 becomes narrower than the width of the display media 5 and 5c, the print unit moving means causes the print unit to move. By performing the serial scanning in the image 2, the image can be rewritten with respect to the entire width of the display media 5 and 5c.
In the display devices 1d and 1e using the image display method for switching still images by repeatedly performing the image forming process and the image switching process, it is only necessary to complete writing of the image for switching before switching the image. Even when an image is formed while performing serial scanning with the small heating discharge type print head 3, the waiting time does not become a problem. The heat discharge type print head 3 can be reduced in size and is excellent in mass productivity.

As described above, the display device according to the fourth embodiment has the following operation in addition to the second or third embodiment.
(1) By moving the heat-discharge type print head 3 and the restoring device 4 by the printing unit moving means, it is possible to perform image writing and restoration processing on the stopped display media 5 and 5c.
(2) A switching image can be written to the display media 5 and 5c in a portion hidden from the display screen side (the front side of the display devices 1d and 1e) during the image display of the display devices 1d and 1e. At the time of switching, only the endless loop display mediums 5 and 5c are moved by the rollers 25a and 25b of the display medium conveying means, so that still images can be switched quickly as if they were picture-story shows.
(3) The control unit 26 can automatically repeat the image writing and restoration processing by the printing unit 2 and the conveyance of the display media 5 and 5c by the rollers 25a and 25b, and can be performed regularly or irregularly on the display screen. The displayed image can be switched.

As described above, according to the image display method of the display device in the fourth embodiment, the following effects are obtained.
(1) Since there is an image forming step of writing a switching image on the display mediums 5 and 5c during the display of the display devices 1d and 1e, the display mediums 5 and 5c that are displaying images are stopped. Images can be written.
(2) Since there is an image switching step of switching between the image being displayed on the display devices 1d and 1e formed on the display media 5 and 5c and the image for switching, the switching image formed in the image forming step of the previous step is displayed. Images can be switched by moving to the display screen side of the display devices 1d and 1e.
(3) Since the still image can be switched sequentially by repeatedly performing the image forming process and the display medium moving process, even when the display devices 1d and 1e are large screens, power saving and still image switching are possible. If it is used instead of a movie signboard, a still image of a typical scene can be rewritten and displayed periodically or irregularly.

  The present invention provides a display device that can achieve both a large display screen and a high-definition display screen, and is excellent in practicality and visibility, and does not require energization when displaying a still image, and is excellent in energy saving. In addition, it is possible to provide an image display method of a display device with excellent functionality that can shorten the time required for switching the display screen, and it can be suitably used as an advertisement display medium.

Claims (14)

(A) a driver comprising a discharge part having a discharge electrode and a heating means having a heat generating part for heating the discharge electrode, wherein the driver controls an arrangement surface of the discharge generating part of the discharge electrode and heat generation of the heat generating part A printing unit equipped with a heating and discharging type print head that controls the generation of discharge by controlling the temperature of each of the discharge electrodes to which a discharge control voltage is applied, and the IC placement surface is not on the same plane; and b) a display medium on which a visible image appears by discharge from the heat-discharge type print head. Arrangement scheme of the discharge generating portion of the discharge electrode, the end face type positioning the discharge generating portion of the discharge electrode on the end face of the substrate on which the driver IC is disposed, the said discharge electrode to the edge of the substrate 2. An edge type in which a discharge generating part is arranged, or a raised type in which the discharge generating part of the discharge electrode is arranged on a raised surface of a raised part formed on the surface of the substrate. Item 4. The display device according to Item 1. The display device according to claim 1, wherein a head substrate having the heat generating part and the discharge part is disposed on a heat radiating plate. 4. The display device according to claim 1 , wherein the printing unit includes a restorer that initializes display contents of the display medium and performs a restoration process. 5. Wherein the display medium, either the heat-discharge type print head which faces and further comprising a side opposite the ground electrode portion is disposed on the surface of or a positive voltage application unit and said of claims 1 to 4 Item 1. A display device according to item 1. 6. The display device according to claim 1 , further comprising a light source unit disposed on either the front surface side or the back surface side of the display medium. The display device according to any one of claims 1 to 6 , wherein display colors of the display medium are at least three primary colors (R, G, B) in an additive color mixing method. The display device according to any one of claims 1 to 6 , wherein the display primary color of the display medium is at least three primary colors (Y, M, C) in a subtractive color mixture method. The display device according to claim 7 or 8 , wherein each color of the display primary colors is arranged in a striped pattern on the display medium. The display according to claim 9 , wherein the display medium includes an indicator disposed in at least one of a direction parallel to or orthogonal to a longitudinal direction of the display primary colors arranged in a striped pattern. apparatus. 7. The display device according to claim 1 , wherein monochromatic display is performed on the entire surface of the display medium or in units of blocks obtained by dividing the display medium. The display device according to claim 1 , further comprising at least one of a printing unit moving unit that moves the printing unit and a display medium transport unit that transports the display medium. . (A) The display medium conveying means includes at least two rollers and a roller driving unit that rotates at least one of the rollers, and (b) the display medium includes the rollers. The display device according to claim 12 , wherein the display device is wound in an endless loop shape. (A) an image forming step of writing an image for switching on the display medium during image display of the display device according to claim 13 ; and (b) an image being displayed on the display device formed on the display medium. And an image switching process for switching between the images for switching.

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