KR20090016155A

KR20090016155A - Magnetic field controlled active reflector and magnetic display panel empolying the same

Info

Publication number: KR20090016155A
Application number: KR1020070080601A
Authority: KR
Inventors: 조승래
Original assignee: 삼성전자주식회사
Priority date: 2007-08-10
Filing date: 2007-08-10
Publication date: 2009-02-13

Abstract

An active reflector and a magnetic display panel adopting the same are provided to determine whether to pass or reflect the light by the magnetic field. A magnetic display panel(100) comprises the followings: a magnetic layer(130) which passes the light when the external magnetic field is applied and prevents the transmission of the light when the external magnetic field is not applied; a reflector(131) which is arranged at a lower part of the magnetic layer to reflect the light penetrating the magnetic layer; the first electrode(120) arranged at a lower part of the reflector; the second electrode(125) arranged at an upper part of the magnetic layer; and a spacer(123) which is arranged at one side of the magnetic layer to electrically connect the first and second electrodes.

Description

Active reflector and magnetic display panel employing the same {Magnetic field controlled active reflector and magnetic display panel empolying the same}

The present invention relates to an active reflector and a magnetic display panel employing the same, and more particularly, to an active reflector that is controlled by a magnetic field to transmit or reflect light, and a magnetic display panel employing the same.

Currently, liquid crystal display (LCD) panels and plasma display panels (PDP) are mainly used as flat panel display panels. In addition, OLED (Organic Light Emitting Diode) has been studied as the next flat panel display panel.

In the case of the liquid crystal display panel, since it is not a self-emission type, an optical shutter that transmits / blocks the light emitted from the backlight unit or external light should be used. As is known, the optical shutter used in the liquid crystal display panel consists of two polarizing plates and a liquid crystal layer disposed between the two polarizing plates. By the way, when the said polarizing plate is an absorption type polarizing plate, there exists a problem that light utilization efficiency falls significantly. Accordingly, research for using a reflective polarizer instead of an absorption polarizer is being conducted, but in this case, manufacturing costs increase and it is difficult to realize a large area display panel.

In addition, the plasma display panel does not require an optical shutter as a self-luminous type, but has a problem in that power consumption is large and heat is generated. In addition, OLEDs are also self-luminous and do not require optical shutters. OLEDs are still in the development stage, which is problematic in that manufacturing costs are high and their lifetime is not long enough.

Meanwhile, in the case of a dual-sided LCD currently being developed, a reflective structure that utilizes external light may be employed in the pixel to improve outdoor visibility. There is no control to transmit or reflect. Therefore, in the current double-sided display device, the brightness of both sides of the display may vary according to the position of the external light source.

The present invention is to improve the above-mentioned conventional problems, it is an object of the present invention to provide an active reflector that can be controlled whether the transmission or reflection of light by a magnetic field.

Another object of the present invention is to provide a magnetic display panel employing the principle of the active reflector described above.

Further, another object of the present invention is to provide a double-sided display panel employing the principle of the active reflector described above.

An active reflector according to one type of the present invention includes a magnetic material layer in which magnetic particles are embedded in a transparent insulating medium, and the light incident surface of the magnetic material layer has a convex parabolic shape having a central axis of symmetry and And an array of hybrid curved surfaces having a focus on the axis of symmetry of the central plane and comprising a concave parabolic surface extending from the central plane.

The magnetic material layer may reflect all light when the external magnetic field is not applied, and transmit the light in the first polarization direction when the external magnetic field is applied, and reflect light in the second polarization direction perpendicular to the first polarization direction.

Here, the thickness of the magnetic material layer is preferably larger than the magnetic attenuation length of the magnetic material layer.

The magnetic material layer may be one in which magnetic particles of the core-shell structure and color absorbing particles of the core-shell structure are mixed and distributed in one medium.

The magnetic particles of the core-shell structure may include a magnetic core made of a conductive magnetic body and an insulating shell around the magnetic core.

The insulating shell may be made of a transparent insulating material surrounding the magnetic core.

Alternatively, the insulating cell may be made of a transparent insulating surfactant in the form of a polymer surrounding the magnetic core.

According to the present invention, one magnetic core may form one single magnetic domain.

For example, the conductive magnetic body forming the magnetic core is cobalt, iron, iron oxide, nickel, Co-Pt alloy, Fe-Pt alloy, titanium, aluminum, barium, platinum, sodium, strontium, magnesium, dysprosium, manganese, gadolinium , Silver, copper and chromium may be made of any one material or an alloy thereof.

When the magnetic attenuation length of the magnetic core at the wavelength of the incident light is s and the diameter of the magnetic core is d, the number of magnetic cores needed along the path of light traveling in the thickness direction of the inside of the magnetic material layer is n is n. May be ≥ s / d.

According to the present invention, the size of the color absorbing particles is preferably smaller than or equal to the size of the magnetic particles.

In addition, the color-absorbing particles of the core-shell structure may be composed of a core made of a dielectric and a shell made of metal.

According to the present invention, color absorbing particles having different radius ratios of the core and the shell may be distributed in the magnetic material layer.

The magnetic material layer may be formed by immersing magnetic particles having a core-shell structure in a solution together with a dye and then coating and curing the same on a transparent substrate.

The active reflector according to the present invention further includes magnetic field applying means for applying a magnetic field to the magnetic material layer, wherein the magnetic field applying means includes a plurality of wires and the plurality of wires arranged in parallel with each other around the magnetic material layer. It characterized in that it comprises a power supply for providing a current to the field.

Here, the wires may be arranged to surround the circumference of the magnetic material layer.

In addition, the wires may be disposed on any one of an upper surface and a lower surface of the magnetic material layer.

For example, the wire may be made of any one material selected from ITO, aluminum, copper, silver, platinum, gold and iodine doped polyacetylene.

The active reflector according to the present invention further includes magnetic field applying means for applying a magnetic field to the magnetic material layer, wherein the magnetic field applying means is a plate-shaped transparent electrode disposed on the surface of the magnetic material layer and a current to the transparent electrode. It characterized in that it comprises a power supply to provide.

For example, the plate-shaped transparent electrode may be made of a conductive metal having a thickness thinner than ITO or surface depth.

On the other hand, the magnetic display pixel according to another type of the present invention, a magnetic material layer that transmits the light when the external magnetic field is applied, and does not transmit the light when the external magnetic field is not applied; A reflector disposed under the magnetic material layer to reflect light transmitted through the magnetic material layer; A first electrode disposed below the reflector; A second electrode disposed on the magnetic material layer; And a spacer disposed at a side of the magnetic material layer to electrically connect the first electrode and the second electrode, wherein the dye or color absorbing particles are mixed in the magnetic material layer.

In addition, the magnetic display pixel according to the present invention may further include a transparent front substrate disposed on the first electrode and a rear substrate disposed on the second electrode.

According to the present invention, the magnetic material layer transmits light in a first polarization direction when an external magnetic field is applied, reflects light in a second polarization direction perpendicular to the first polarization direction, and transmits all light when no external magnetic field is applied. Can reflect.

The magnetic material layer may have a structure in which magnetic particles are embedded in a transparent insulating medium without agglomeration with each other.

According to the present invention, the thickness of the magnetic material layer is preferably larger than the magnetic attenuation length of the magnetic material layer.

For example, the magnetic material layer may be a core-shell structured magnetic particles and color absorbing particles are mixed and distributed in one medium.

In addition, the insulating cell may be made of a transparent insulating surfactant in the form of a polymer surrounding the magnetic core.

According to the invention, it is preferred that one magnetic core forms one single magnetic domain.

According to the present invention, when the magnetic attenuation length of the magnetic core at the wavelength of the incident light is s and the diameter of the magnetic core is d, the magnetic core required along the path of the light traveling in the thickness direction inside the magnetic material layer in the thickness direction. The number n of may be n ≥ s / d.

The size of the color absorbing particles is preferably less than or equal to the size of the magnetic particles.

For example, the color absorbing particles may be composed of a core made of a dielectric and a shell made of a metal.

In addition, the magnetic material layer may be formed by immersing the magnetic particles of the core-shell structure in a solution together with a dye, and then coating the cured material on a front or rear substrate.

The magnetic display pixel may further include an antireflective coating formed on at least one of the optical surfaces from the magnetic material layer to the outer surface of the front substrate.

In addition, the magnetic display pixel may further include an absorption type polarizer disposed on any one surface of the optical surface from the magnetic material layer to the outer surface of the front substrate.

According to the present invention, the reflecting surface of the reflecting plate includes a convex parabolic center surface having an axis of symmetry in the center and a hybrid curved surface including a concave parabolic surface extending from the center surface with a focus on the axis of symmetry of the center plane. It may have an array form of these.

In addition, the first electrode, the second electrode, and the conductive spacer may be made of any one material of aluminum, copper, silver, platinum, gold, and iodine doped polyacetylene.

In this case, a plurality of first holes are formed in the first electrode so that light can pass through the first electrode, and a plurality of wires extending in a direction in which current flows may be formed between the first holes. have.

A light transmissive material may be formed in the first hole region between the wires.

In addition, a second hole may be formed in a region of the second electrode that faces the magnetic material layer so that light may pass through the second electrode.

A light transmissive material may be formed in the second hole region of the second electrode.

The second electrode may be a wire of mesh or lattice structure electrically connected to the conductive spacer.

In addition, the first electrode and the second electrode may be made of a transparent conductive material.

The magnetic display pixel may be disposed on a side surface of the magnetic material layer between the front substrate and the substrate, and may further include a control circuit for switching a current flow between the first electrode and the second electrode.

The magnetic display pixel may further include a black matrix disposed between the front substrate and the common electrode in an area facing the control circuit and the conductive spacer.

A magnetic display panel according to another type of the invention is characterized by having an array of magnetic display pixels of the above-described structure.

According to the present invention, the magnetic display panel may be a flexible display panel made of a flexible material of the back substrate, the front substrate, the first electrode, and the second electrode.

In this case, the front and rear substrates may be made of a transparent resin material, and the first and second electrodes may be made of a conductive polymer material.

The magnetic display panel may be disposed on a side of the magnetic material layer between the front and rear substrates, and may further include an organic thin film transistor configured to switch current flow between the first electrode and the second electrode.

The magnetic display panel may include a display unit in which a plurality of pixels are arranged and a separate controller for individually switching current flow between the first electrode and the second electrode for each pixel.

According to the present invention, a plurality of pixels share one common front substrate, back substrate, and second electrode, and a magnetic material layer and a first electrode for applying a magnetic field to the magnetic material layer may be disposed one for each pixel. have.

On the other hand, the double-sided display panel according to another type of the invention is characterized in that the first and second magnetic display panel having the above-described structure is arranged in a symmetrical configuration with each other facing the rear substrate.

In this case, it is preferable that the said back substrate is transparent.

According to the present invention, the reflecting plates of the first and second magnetic display panels are composite reflectors in which active reflectors and inactive reflectors are alternately arranged, and the active reflector includes a magnetic material layer in which magnetic particles are embedded in a transparent insulating medium. And reflects all light when the external magnetic field is not applied, and transmits the light in the first polarization direction and reflects the light in the second polarization direction perpendicular to the first polarization direction when the external magnetic field is applied.

According to the present invention, a backlight unit may be further disposed between the first magnetic display panel and the second magnetic display panel.

In addition, an electronic device according to another type of the present invention may employ a magnetic display panel having the above-described structure.

The active reflector according to the present invention can control reflection or transmission of incident light depending on whether a magnetic field is applied. When the active reflector according to the present invention is used in a double-sided display panel, it is possible to improve outdoor visibility.

In addition, in the case of the magnetic display panel according to the present invention, it is not necessary to use the color filter, the front polarizer and the back polarizer which are essential for the conventional liquid crystal display panel. Therefore, the transmission / blocking of light can be controlled even with much fewer components compared with the conventional liquid crystal display panel, and thus it is possible to manufacture the display panel simply and inexpensively as compared with the conventional liquid crystal display panel. In addition, by using an active reflector, external light can be used more efficiently.

In addition, the magnetic display panel according to the present invention can use most of the existing manufacturing process of the liquid crystal display panel, it is possible to utilize the current production line of the liquid crystal display panel as it is.

Furthermore, since the magnetic display panel according to the present invention does not require a high temperature process, the magnetic display panel can be applied to a flexible display.

The magnetic display panel according to the present invention is easy to manufacture not only in a small area but also in a large area. Therefore, the magnetic display panel according to the present invention can be widely applied to electronic devices of various sizes in which an image is provided, such as a TV, a PC, a notebook, a mobile phone, a PMP, a game machine, and the like.

FIG. 1 exemplarily shows a schematic structure of an active reflector 10 according to a preferred embodiment of the present invention, and FIG. 2 shows a cross-sectional view of the active reflector 10 shown in FIG. 1 and 2, the active reflector 10 includes a transparent substrate 11 and a magnetic material layer 12 formed on the transparent substrate 11. The magnetic material layer 12 may be, for example, a structure in which a plurality of magnetic particles 13 are embedded in the transparent insulating medium 15. 1 and 2 illustrate that magnetic particles 13 in the magnetic material layer 12 are densely distributed for convenience. In practice, however, the magnetic particles 13 are very densely packed in the magnetic material layer 12.

Here, the magnetic particles 13 made of a conductive magnetic core are preferably embedded in the transparent insulating medium 15 without agglomeration or electrical contact with each other. As enlarged in FIGS. 1 and 2, the magnetic particles 13 are formed of conductive magnetic cores 13a so that the magnetic particles 13 made of conductive magnetic cores do not agglomerate or electrically contact with each other. It may be made of a transparent nonmagnetic, insulating shell 13b surrounding it. In addition, the region between the magnetic particles 13 may also be filled with a transparent insulating dielectric material having a nonmagnetic similarity to the insulating shell 13b.

As a material that can be used as the core 13a of the magnetic particles 13, any material can be used as long as it has both a conductor and a magnetic property. For example, ferromagnetic or superparamagnetic metals or alloys such as cobalt, iron, nickel, Co-Pt alloys or Fe-Pt alloys may be used, or titanium, aluminum, barium, platinum, sodium, strontium, magnesium, dysprosium, manganese and Use of paramagnetic metals or alloys such as gadolinium, diamagnetic metals or alloys such as silver and copper, or use of antiferromagnetic metals such as chromium that turn paramagnetic above Neel temperature It is possible. In addition to the metals, materials such as dielectrics, semiconductors, polymers, and the like can be used as long as they have properties as conductors and magnetic materials. In addition, ferrimagnetic materials having low conductivity but high magnetic susceptibility can also be used as the core 13a. Examples of such materials include MnZn (Fe ₂ O ₄ ) ₂ and MnFe ₂ O _4. Iron oxides such as Fe ₃ O ₄ and Fe ₂ O ₃ , and Sr ₈ CaRe ₃ Cu ₄ O ₂₄ .

The diameter of this core 26a should be small enough that one core 26a can form a single magnetic domain. Therefore, the diameter of the core 26a of the magnetic particles 26 can be from several nm to several tens nm depending on the material used. For example, the diameter of the core 26a may vary depending on the material used, but may be about 1 nm to 100 nm.

In addition, the role of the shell 13b is to prevent the electrical contact between the cores 13a by preventing the cores 13a of the magnetic particles 13 from sticking together or directly touching each other, as described above. To this end, a shell 13b made of a non-magnetic transparent insulating dielectric material such as SiO ₂ or ZrO ₂ may surround the core 13a. In addition, as shown in FIG. 3, a shell 13b ′ made of a surfactant in the form of a polymer may surround the core 13a. Here, the surface active agent in the polymer form should be transparent, insulating and nonmagnetic. The thickness of the shells 13b and 13b 'is sufficient so that the cores 13a of the magnetic particles 13 adjacent to each other are not electrically conductive to each other.

The magnetic material layer 12 may be, for example, by immersing the core-shell structured magnetic particles 13 in a solution, and then thinly spin coating or deep coating the transparent substrate 11 on the transparent substrate 11. It can be formed by curing. In addition, if the magnetic particles 13 can be present in the magnetic material layer 12 without being agglomerated or electrically contacted with each other, various other methods may be used.

4 schematically shows the orientation of the magnetic moments in the magnetic material layer 12 when no external magnetic field is applied. When no external magnetic field is applied, the overall magnetic moments in the magnetic material layer 12 are randomly oriented in various directions as indicated by arrows in FIG. 4. In Fig. 4, '·' represents a magnetic moment in the + x direction on the x-y plane, and 'x' represents a magnetic moment in the -x direction on the x-y plane. 4, the magnetic moments in the magnetic material layer 12 are randomly oriented not only in the x-y plane but also in the vertical direction (that is, the -z direction). Therefore, when no external magnetic field is applied, the total magnetization in the magnetic material layer 12 becomes zero (M = 0).

5 illustrates a case where a magnetic field is applied around the magnetic material layer 12. In order to apply a magnetic field around the magnetic material layer 12, as shown in FIG. 5, a plurality of wires 16 may be arranged around the magnetic material layer 12 as a magnetic field applying means. Here, the wires 16 may use a transparent conductive material such as, for example, ITO. However, if the spacing between the wires 16 is much greater than the width of the wires 16, then the opaque, low resistance, such as aluminum, copper, silver, platinum, gold, barium, chromium, sodium, strontium, magnesium, etc., instead of ITO Metals may also be used. In addition to the metal, it is also possible to use a conductive polymer such as iodine-doped polyacetylene as the material of the wire 16. Although the wire 16 is illustrated as being disposed on the bottom surface of the magnetic material layer 12 in FIG. 5, the wire 16 may be disposed on the top surface of the magnetic material layer 12 or may be arranged to surround the magnetic material layer 12. have.

In addition, although not shown, a plate-shaped electrode made of a transparent conductive material such as ITO may be formed on the entire surface of the magnetic material layer 12 instead of the wire 16. Recently, a technology for coating a metal very thin, such as several nm or less, has been developed. When the conductive metal is formed to a thickness less than or equal to the skin depth of the metal, light transmission is possible. Therefore, the electrode may be formed by thinly coating the conductive metal on the entire surface of the magnetic material layer 12 to a thickness smaller than the surface depth.

When a magnetic field is applied around the magnetic material layer 12 using the magnetic field applying means, the magnetic moments in the magnetic material layer 12 are aligned in one direction along the magnetic field. For example, as shown in FIG. 5, when current flows along the wires 16 in the -y direction, the magnetic moments in the magnetic material layer 12 are oriented in the -x direction. Thus, the magnetic material layer 12 is magnetized in the -x direction.

Hereinafter, the operation principle of the magnetic material layer 12 having the above-described structure will be described.

The magnetic field of the electromagnetic wave incident on the magnetic material layer 12 may be decomposed into a component H _⊥ and a horizontal component H _|| perpendicular to the magnetization direction of the magnetic material layer 12. When a component H _|| parallel to the magnetization direction is incident on the magnetic material layer 12, an induced magnetic moment is generated by interacting with magnetic moments oriented in the magnetization direction. The induced magnetic moments thus change with time as the amplitude of the magnetic field of the horizontal component H _|| changes with time. As a result, according to the general principle of electromagnetic radiation, electromagnetic waves are generated by time-varying induced magnetic moments. The electromagnetic waves thus generated can propagate in all directions. However, electromagnetic waves traveling in the magnetic material layer 12 (that is, electromagnetic waves traveling in the -z direction) are attenuated by the magnetic material layer 12. If the thickness t of the magnetic material layer 12 is larger than the magnetic decay length, a concept similar to the skin depth length of an electric field, the magnetic material layer ( Most of the electromagnetic waves propagating in the inside of 12) are attenuated and only the electromagnetic waves traveling in the + z direction remain. Thus, the component H _|| parallel to the magnetization direction can be considered to be reflected by the magnetic material layer 12.

On the other hand, when the component H _수직 perpendicular to the magnetization direction is incident on the magnetic material layer 12, the vertical component H _하지 does not interact with the magnetic moment, and thus no induced magnetic moment occurs. As a result, the component H _수직 perpendicular to the magnetization direction passes through the magnetic material layer 12 without attenuation.

As a result, in the magnetic field of the electromagnetic wave incident on the magnetic material layer 12, the component H _|| parallel to the magnetization direction is reflected by the magnetic material layer 12, while the component H perpendicular to the magnetization direction is reflected. _Iii ) is transmitted through the magnetic material layer 12. Thus, the light energy ( S _|| = E _|| × H _|| ) associated with the magnetic field of the component parallel to the magnetization direction is reflected by the magnetic material layer 12 and associated with the magnetic field of the component perpendicular to the magnetization direction Light energy ( S _⊥ = E _⊥ × H _⊥ ) passes through the magnetic material layer 12.

As shown in FIG. 4, when no external magnetic field is applied to the magnetic material layer 12, the magnetic moments in the magnetic material layer 12 are randomly oriented not only in the xy plane but also in the depth direction (ie, the -z direction). It is. Therefore, all light incident on the magnetic material layer 12 to which no external magnetic field is applied is reflected. On the other hand, as shown in FIG. 5, when an external magnetic field is applied to the magnetic material layer 12, the magnetic moments in the magnetic material layer 12 are aligned in one direction. Therefore, among the light incident on the magnetic material layer 12, the light of the polarization component related to the magnetic field component parallel to the magnetization direction is reflected by the magnetic material layer 12, and the polarization associated with the magnetic field component perpendicular to the magnetization direction The light of the component is transmitted through the magnetic material layer 12. In this regard, the magnetic material layer 12 includes an active optical shutter or an active reflector that reflects all incident light when no external magnetic field is applied, and partially transmits incident light when an external magnetic field is applied. reflector).

On the other hand, in order for the magnetic material layer 12 to sufficiently reflect the incident light, the magnetic material layer 12 should have a thickness capable of sufficiently attenuating the electromagnetic waves propagating inside the magnetic material layer 12. That is, as described above, the thickness of the magnetic material layer 12 should be greater than the magnetic attenuation length of the magnetic material layer 12. In particular, when the magnetic particles of the magnetic material layer 12 are made of magnetic cores dispersed in the medium, a sufficient number of magnetic cores must exist in the magnetic material layer 12 along the path of light propagation. For example, assuming that the magnetic material layers 12 are formed by stacking layers on the xy plane in which magnetic cores are uniformly distributed in a single layer in the z direction, the number of magnetic cores required along the path of light traveling in the -z direction. n may be given by the following equation.

n ≥ s / d

Where s is the magnetic attenuation length of the magnetic core at the wavelength of the incident light and d is the diameter of the magnetic core. For example, when the diameter of the magnetic core is 7 nm and the magnetic attenuation length of the magnetic core at the wavelength of incident light is 35 nm, at least five magnetic cores are required along the path of the light. Accordingly, when the magnetic material layer 12 is formed of a plurality of magnetic cores dispersed in a medium, the magnetic material layer may be formed such that at least n magnetic cores exist in the thickness direction of the magnetic material layer 12 in consideration of the density of the magnetic core. The thickness of (12) can be determined.

6 and 7 show simulation results for confirming the characteristics of the active reflector 10 according to the present invention. FIG. 6 is a graph showing the intensity (A / m) of the time-varying magnetic field passing through the active reflector 10 in the state where an external magnetic field is applied, and FIG. 7 is an enlarged graph of a portion of FIG. 6. 6 and 7 show results obtained when titanium is used as the magnetic material of the magnetic material layer 12 and the incident light has a wavelength of 550 nm. Titanium has a magnetic susceptibility of about 18 × 10 ⁻⁵ and an electrical conductivity of about 2.38 × 10 ⁶ S (Siemens) at room temperature of 20 ° C., as is known. 6 and 7, in the case of a magnetic field perpendicular to the magnetization direction of the magnetic material layer 12, the magnetic material layer 12 passes through the magnetic material layer 12 without attenuation loss even when the thickness of the magnetic material layer 12 increases. . On the other hand, the magnetic field parallel to the magnetization direction of the magnetic material layer 12 is greatly attenuated and the amplitude becomes close to zero at about 60 nm. Therefore, when titanium is used as the magnetic material of the magnetic material layer 12 of the active reflector 10 according to the present invention, it is appropriate that the thickness of the magnetic material layer 12 is about 60 nm or more.

8A and 8B exemplarily illustrate another possible structure of the magnetic material layer 12, in which FIG. 8A shows a horizontal cross section and FIG. 8B shows a vertical cross section. The magnetic material layer 12 shown in FIGS. 8A and 8B has a structure in which magnetic particles 17 in the form of cylinder pillars are embedded in a transparent insulating dielectric material 15 such as SiO ₂ instead of the core-shell. Even in this case, each of the magnetic particles 17 has a size enough to form one single magnetic domain, and can be formed using the magnetic material described above. Such a structure can be made by, for example, forming a dielectric template having fine pores by using an anodizing method, and filling the magnetic material with a sputtering method or the like.

1 and 2, in the case of the active reflector 10 according to the preferred embodiment of the present invention, the magnetic material layer may be used to simultaneously perform a function of a color filter for transmitting light to have a specific color. 12 may further include a plurality of color absorbing particles 14. In this case, the magnetic material layer 12 may have a structure in which the plurality of color absorbing particles 14 together with the plurality of magnetic particles 13 are embedded in one transparent insulating medium 15.

Here, the color absorbing particles 14 may be formed in a core-shell structure similarly to the magnetic particles 13 as shown in an enlarged view in FIGS. 1 and 2. In the case of the magnetic particles 13, the core 13a is made of metal and the shell 13b is made of a dielectric, whereas in the case of the color absorbing particles 14, the core 14a is made of a dielectric and the shell 14b is made of metal. There is a difference in that it is made. For example, gold, silver or aluminum may be mainly used as the shell 14b of the color absorbing particles 14, and SiO ₂ may be mainly used as the core 14a of the color absorbing particles 14. The core-shell structured color absorbing particles 14 are widely used in filters for absorbing wavelengths in specific bands. As is generally known, when light is incident on a thin metal film formed on a dielectric, surface plasmon resonance occurs at the interface between the dielectric and the metal film to absorb light of a specific wavelength band. Here, the resonance wavelength is independent of the size of the core-shell structure, only determined by the ratio of the radius of the core and the shell. However, in order for surface plasmon resonance to occur, it is suitable that the diameter of the color absorbing particle 14 is about 50 nm or less.

1 and 2 illustrate that the same type of color absorbing particles 14 are distributed in the magnetic material layer 12, but various types of color absorbing particles 14 may be mixed and distributed. For example, when the green is to be realized, the color absorbing particles absorbing the red band light and the color absorbing particles absorbing the blue band light may be mixed together in the magnetic material layer 12. In addition, when red is to be realized, color absorbing particles absorbing wavelengths of the green band and color absorbing particles absorbing light of the blue band may be mixed together and distributed in the magnetic material layer 12. Accordingly, the color absorbing particles 14 distributed in the magnetic material layer 12 may have different ratios of radii of the core and the shell.

In addition, the color absorbing particles 14 need not necessarily be spherical, and may be in the form of nanorods. Even if the color absorbing particles 14 are in the form of nanorods, light of a specific wavelength band can be absorbed by surface plasmon resonance, in which case the resonance wavelength is determined by the aspect ratio of the nanorods. Therefore, the color absorbing particles 14 in the magnetic material layer 12 may be mixed with those having the shape of nanorods having different aspect ratios and those having the shape of spheres having different ratios of the radius of the core and the shell.

The active reflector 10 according to the present invention having the magnetic material layer 12 in which the color absorbing particles 14 are mixed serves as a mirror when no external magnetic field is applied, and serves as a color filter when an external magnetic field is applied. can do. Here, the size of the core-shell structure of the color absorbing particles 14 is preferably smaller than or similar to that of the core-shell structure of the magnetic particles 13. This is because when the size of the color absorbing particles 14 is too large than the size of the magnetic particles 13, the function of the active reflector 10 may be degraded.

As described above, the distribution of the color absorbing particles 14 in the magnetic material layer 12 is for the active reflector 10 to have the function of a color filter. Therefore, the magnetic material layer 12 may be embodied in another form as long as it can simultaneously perform the function of the color filter without affecting the functions of the magnetic particles 13. For example, the magnetic material layer 12 may be formed by dispersing the core-shell structured magnetic particles 13 in a liquid or paste color filter medium and curing the core particles. In addition, the magnetic material layer 12 may be formed by immersing the core-shell structured magnetic particles 13 in a solution together with the color filter dye and then coating the thin particles on the transparent substrate 11 to cure.

On the other hand, the surface of the magnetic material layer 12 of the active reflector according to the present invention may have a predetermined shape in order to focus the reflected light or transmitted light uniformly in a specific area. 9 to 11 show the surface shape of the magnetic material layer 12 of the active reflector according to the present invention and various magnetic field application methods.

Referring to FIG. 9, the surface of the magnetic material layer 12 may be formed as an array of hybrid curved surfaces in which two types of curved surfaces are mixed. For example, the central plane 12a may have the form of a convex parabolic surface having an axis of symmetry in the center. The circumferential surface 12b around the center surface 12a is a concave curved surface, and may have a concave parabolic surface extending from the center surface 12a and having a focus on the axis of symmetry of the center surface 12a. . In this case, most of the light reflected or transmitted by the active reflector shown in FIG. 9 proceeds parallel to the axis of symmetry of the central plane 12a. Accordingly, the active reflector shown in FIG. 9 serves as a curved mirror that propagates most of the reflected light in a direction perpendicular to the reflector in the ON state, and transflectively propagates most of the reflected light and transmitted light in the direction perpendicular to the reflector in the OFF state. It can serve as a lens.

Here, a method of applying an external magnetic field to the magnetic material layer 12 may be variously implemented. For example, in the case of FIG. 9, the wire 16 is disposed under the magnetic material layer 12. However, as shown in FIG. 10, a transparent material layer 18 having a flat upper surface may be further formed on the magnetic material layer 12, and the wire 16 may be disposed on the upper surface of the transparent material layer 18. have. 11, it is also possible to arrange the wire 16 directly along the surface of the magnetic material layer 12 without the transparent material layer 18.

As described above, the active reflector 10 according to the present invention is used as an optical shutter because it reflects and blocks all light when no external magnetic field is applied, and partially transmits light when an external magnetic field is applied. It may be. Therefore, it is possible to manufacture the pixels of the display panel using the principle of the magnetic material layer 12 of the active reflector 10 described above.

Hereinafter, the structure and operation of the magnetic display panel according to the preferred embodiment of the present invention will be described in detail.

12 is a cross-sectional view schematically showing the structure of one sub-pixel 100 of the magnetic display panel according to the present invention. Referring to FIG. 10, one subpixel 100 of the magnetic display panel according to the present invention includes a magnetic material layer filled between the rear and front substrates 110 and 140 and the rear and front substrates 110 and 140 disposed to face each other. 130, the subpixel electrode 120 partially formed on the inner surface of the back substrate 110, the common electrode 125 disposed on the inner surface of the front substrate 140, the subpixel electrode 120 and the magnetic material. The reflective plate 131 disposed between the layers 130 and the side of the magnetic material layer 130 to seal the magnetic material layer 130 and electrically connect the subpixel electrode 120 and the common electrode 125. Conductive spacers 123 connected to each other.

Here, one common back and front substrates 110 and 140 and the common electrode 125 may be used for all the subpixels 100 of the magnetic display panel according to the present invention. In the case of the substrates 110 and 140, the front substrate 140 must use a transparent material, but the back substrate 110 may or may not be transparent.

According to the present invention, the magnetic material layer 130 has the same configuration as the magnetic material layer 12 of the active reflector 10 described above. That is, the magnetic material layer 130 may have a structure in which a plurality of magnetic particles and a plurality of color absorbing particles are embedded in one transparent insulating medium. Alternatively, the magnetic material layer 130 may be formed by mixing magnetic particles having a core-shell structure together with the color filter dye. However, in the magnetic material layer 130 of the subpixel 100 of the magnetic display panel according to the present invention, the ferromagnetic material must be in a superparamagnetic state in order to be used as a core of the magnetic particles. In the case of ferromagnetic materials, the alignment state does not tend to be disturbed once the magnetic particles are aligned in one direction. But ferromagnetics behave like paramagnetics in the superparamagnetic domain. In order for a ferromagnetic material to be superparamagnetic, the volume of the magnetic core needs to be smaller than that of a single magnetic domain.

Therefore, as the material of the core of the magnetic particles in the magnetic material layer 130 of the sub-pixel 100 of the magnetic display panel according to the present invention, for example, titanium, aluminum, barium, platinum, sodium, strontium, magnesium, dysprosium, Paramagnetic metals such as manganese and gadolinium or alloys thereof may be used, semimagnetic metals such as silver and copper or alloys thereof may be used, or antiferromagnetic metals such as chromium may be used. In addition, cobalt, iron, nickel, Co-Pt alloy or Fe-Pt a ferromagnetic material such as a portrait alloy may be used to convert a magnetic _{state, MnZn (Fe 2 O 4)} 2, MnFe 2 O 4, Fe 3 O 4, Iron oxides such as Fe ₂ O ₃ and ferrimagnetic materials such as Sr ₈ CaRe ₃ Cu ₄ O ₂₄ may also be used.

Meanwhile, between the back and front substrates 110 and 140, a control circuit 160 for switching the current flow between the subpixel electrode 120 and the common electrode 125 may be formed adjacent to the magnetic material layer 130. Can be. For example, the control circuit 160 may use a thin film transistor (TFT) commonly used in a liquid crystal display panel. In the case of using the thin film transistor, for example, when a voltage is applied to the gate electrode of the thin film transistor, a current flows between the subpixel electrode 120 and the common electrode 125 while the thin film transistor is turned on. In addition, in order to prevent the material forming the magnetic material layer 130 from diffusing to the control circuit 160 side, it is preferable to form a partition wall 175 between the control circuit 160 and the magnetic material layer 130. Do.

In addition, a vertical outer wall 170 is formed between the common electrode 125 and the rear substrate 110 along the edge of the subpixel. The outer wall 170, together with the conductive spacer 123, serves to completely seal the interior between the rear and front substrates 110 and 140 from the outside.

In addition, a black matrix 150 is formed between the front substrate 140 and the common electrode 125 in an area facing the control circuit 160, the outer wall 170, the partition wall 175, and the conductive spacer 123. do. The black matrix 150 serves to make the control circuit 160, the outer wall 170, the partition wall 175, and the conductive spacer 123 invisible from the outside.

The reflective plate 131 disposed between the subpixel electrode 120 and the magnetic material layer 130 is for reflecting external light passing through the magnetic material layer 130 to form an image. As shown in an enlarged view in the lower part of FIG. 12, the reflective plate 131 has a reflected light that forms an image by each pixel 100 of the magnetic display panel toward the front of each pixel of the magnetic display panel. It has a predetermined reflecting surface to proceed. For example, as described above, the surface of the reflective plate 131 may be formed in the form of an array of hybrid curved surfaces in which two types of curved surfaces are mixed. For example, the central plane of each hybrid curved surface of the reflector plate 131 may have the form of a convex parabolic plane having an axis of symmetry in the center, and a circumferential plane around the center plane has a focus on the axis of symmetry of the center plane and the center plane. It may have the form of a concave parabolic surface extending from.

Although not specifically shown in FIG. 12, an antireflective coating is applied to at least one of the optical surfaces from the magnetic material layer 130 to the top surface of the front substrate 140 to prevent glare due to reflection and scattering of external light. It may be formed. For example, an antireflective coating may be applied to at least one of a surface between the magnetic material layer 130 and the common electrode 125, a surface between the common electrode 125 and the front substrate 140, and a top surface of the front substrate 140. Can be formed. Instead of the antireflective coating, it is also possible to arrange an absorbing polarizing plate for absorbing the reflected light reflected from the magnetic material layer 130.

FIG. 13 exemplarily illustrates structures of the subpixel electrode 120, the conductive spacer 123, and the common electrode 125 illustrated in FIG. 12. Referring to FIG. 13, the subpixel electrode 120 faces the bottom surface of the magnetic material layer 130 shown in FIG. 12, and the common electrode 125 faces the top surface of the magnetic material layer 130 and is conductive. The spacer 123 is disposed on one side of the magnetic material layer 130 to electrically connect the subpixel electrode 120 and the common electrode 125.

The subpixel electrode 120, the conductive spacer 123, and the common electrode 125 may be, for example, aluminum (Al), copper (Cu), silver (Ag), platinum (Pt), gold (Au), or barium ( It may be made of an opaque metal having a small resistance such as Ba), chromium (Cr), sodium (Na), strontium (Sr), magnesium (Mg), and the like. In addition to the metal, it is also possible to use a conductive polymer such as iodine-doped polyacetylene as the material of the subpixel electrode 120, the conductive spacer 123, and the common electrode 125.

In the case of using an opaque material, as shown in FIG. 13, light may pass through the subpixel electrode 120 and the common electrode 125 so that light may pass through the subpixel electrode 120 and the common electrode 125. Holes 121 and 126 are formed in regions facing the magnetic material layer 130, respectively. In this case, in order to easily apply a magnetic field to the magnetic material layer 130, a plurality of relatively small holes 121 are formed side by side in the subpixel electrode 120, and a plurality of holes extending in the direction of current flow. Wires 122 are left between the holes 121. On the other hand, one relatively large hole 126 having the same size as the magnetic material layer 130 may be formed in the common electrode 125.

14A exemplarily illustrates a magnetic field formed around the wire 122 when a current is applied to the wires 122 thus formed. As can be seen through FIG. 14A, the magnetic fields do not cancel each other in the spaces between the wires 122, and the magnetic fields are formed in parallel as the distance from the wires 122 increases. Therefore, it is preferable that the magnetic material layer 130 does not penetrate the space between the wires 122. In addition, the magnetic material layer 130 may be disposed at a predetermined distance from the wire.

FIG. 14B is a cross-sectional view taken along the line AA ′ of FIG. 13, illustrating exemplary structures of the subpixel electrode 120, the magnetic material layer 130, the reflector 131, and the common electrode 125. Referring to FIG. 14B, light transmitting materials 121w and 126w may be filled in the holes 121 formed between the wires 122 of the subpixel electrode 120 and the holes 126 of the common electrode 125, respectively. . In addition, a light transmissive material 130p having a predetermined thickness may be interposed between an interface between the subpixel electrode 120 and the reflector 131 and an interface between the common electrode 125 and the magnetic material layer 130. . Instead of the interface between the subpixel electrode 120 and the reflecting plate 131, it is also possible to interpose a light transmissive material 130p at the interface between the reflecting plate 131 and the magnetic material layer 130. In this way, a uniform magnetic field may be applied to the magnetic material layer 130 as a whole, and the magnetic material layer 130 may be prevented from penetrating into the area of the hole 121 between the wires 122 having little or no magnetic field. can do.

However, as a material of the subpixel electrode 120 and the common electrode 125, a conductive material transparent to visible light, such as ITO, may be used. In this case, it is not necessary to separately form the holes in the subpixel electrode 120 and the common electrode 125. In addition, recently, a technology for coating a metal very thinly to several nm or less has been developed. When the conductive metal is formed to a thickness less than or equal to the skin depth of the metal, light transmission is possible. Accordingly, the subpixel electrode 120 and the common electrode 125 may be formed by thinly coating the conductive metal to a thickness smaller than the surface depth.

15 to 17 schematically illustrate various structures of an array of a plurality of subpixels 100 and a common electrode 125 common to the plurality of subpixels in the magnetic display panel according to the present invention.

First, referring to FIG. 15, the magnetic display panel 300 may be configured of a plurality of subpixel arrays two-dimensionally arranged on one common rear substrate 110, and subpixels having different colors of colors may be formed. One pixel can be formed. For example, as shown in FIG. 15, a subpixel 100R having a red color, a subpixel 100G having a green color, and a subpixel 100B having a blue color form one pixel. Can be. As described above, the color of each subpixel 100R, 100G, 100B may be determined according to color absorbing particles or dyes mixed in the magnetic material layer 130.

In addition, the subpixels of the magnetic display panel 300 according to the present invention have one common common electrode 125. In the case of FIG. 15, the common electrode 125 is a transparent electrode made of a transparent conductive material such as ITO. In this case, it is not necessary to form a hole for passing light through the common electrode 125. In this structure, current flows from the common electrode 125 to the subpixel electrode 120 of the corresponding subpixel through the conductive spacer 123 only when the control circuit 160 disposed in each subpixel is turned on. do. At this time, since the current flows along a very large area in the common electrode 125, the current flows along a very narrow area in the subpixel electrode 120, so that the current density in the subpixel electrode 120 is the common electrode 125. It is much greater than the current density in. Therefore, the magnetic material layer 130 is only affected by the subpixel electrode 120 and is hardly affected by the common electrode 125.

16 and 17 illustrate a case where the common electrode 125 is made of an opaque metal or a conductive polymer. In FIG. 16, as shown in FIG. 13, the common electrode 125 has holes 126 for transmitting light at positions corresponding to one subpixel. In FIG. 17, a larger hole 127 is formed in the common electrode 125 to transmit light at each position corresponding to one pixel of three subpixels. According to the present invention, the structure of the common electrode 125 is not limited to the form shown in FIGS. 15 to 17. 15 to 17, the common electrode 125 is shown as a plate, but may be formed of, for example, a wire having a mesh or grid structure. The common electrode 125 may be electrically connected to the conductive spacers 123 of the respective subpixels, regardless of the shape thereof. 15 to 17 illustrate that the common electrode 125 is disposed between the front substrate 140 and the magnetic material layer 130. However, when the common electrode 125 is formed of a wire having a mesh or lattice structure, It may be arranged in another location. For example, both the common electrode 125 and the subpixel electrode 120 may be formed on the same substrate.

Hereinafter, the operation of one sub-pixel 100 of the magnetic display panel according to the preferred embodiment of the present invention will be described in detail.

First, FIG. 18 shows a case where no current flows to the subpixel electrode 120 when the control circuit 160 (see FIG. 12) is OFF. In this case, since the magnetic field is not applied to the magnetic material layer 130, the magnetic moments in the magnetic material layer 130 are oriented in a random direction. Therefore, as described above, all light incident on the magnetic material layer 130 is reflected. As illustrated in FIG. 18, light S and P incident on the magnetic material layer 130 through the front substrate 140 from an external light source are all reflected by the magnetic material layer 130.

FIG. 19 shows a case where current flows to the subpixel electrode 120 when the control circuit 160 (see FIG. 12) is in the ON state. In this case, since an external magnetic field is applied to the magnetic material layer 130 through the subpixel electrode 120, all magnetic moments in the magnetic material layer 130 are oriented in one direction. Therefore, as described above, the light of the polarization component (hereinafter, the light of the P polarization component) associated with the magnetic field component parallel to the magnetization direction of the magnetic material layer 130 is reflected by the magnetic material layer 130, and is magnetized. Light of the polarization component (hereinafter referred to as S polarization component) associated with the magnetic field of the component perpendicular to the direction is transmitted through the magnetic material layer 130.

For example, as shown in FIG. 19, of the light incident from the external light source into the magnetic material layer 130 through the front substrate 140, the light S of the S-polarized light component is directly exposed to the magnetic material layer 130. Will pass. Thereafter, the light S of the S-polarized component is reflected by the reflecting plate 131 under the magnetic material layer 130, and then goes out through the magnetic material layer 130 and the front substrate 140 again. . In this process, the light S has a specific color according to the color absorbing particles or dyes in the magnetic material layer 130. Therefore, each subpixel of the magnetic display panel according to the present invention can implement a color image without a separate color filter. On the other hand, the light P of the P polarization component incident on the magnetic material layer 130 through the front substrate 140 is reflected on the surface of the magnetic material layer 130. The reflected light P does not contribute to image formation and may cause the observer's eyes to fatigue. Therefore, as described above, an absorption type polarizing plate for absorbing only the light P of the P polarization component or antireflection is disposed on at least one of the optical surfaces from the magnetic material layer 130 to the front substrate 140. A coating can be formed.

20 and 21 are cross-sectional views showing the schematic structure of the sub-pixels of the double-sided magnetic display panel using the sub-pixels of the magnetic display panel shown in FIG. 12, showing only two sub-pixels facing each other for convenience. First, referring to FIG. 20, one subpixel 100a of the first magnetic display panel and one subpixel of the second magnetic display panel are provided on both surfaces of a back light unit (BLU) 200 for providing light. 100b is arranged in a symmetrical configuration, with each back substrate 110a, 110b facing each other. 21, the subpixel 100a of the first magnetic display panel and the subpixel 100b of the second magnetic display panel are formed around one common back substrate 110 without using a backlight unit. Each is arranged in a symmetrical configuration. Here, the structures of the subpixels 100a and 100b of the first and second magnetic display panels are exactly the same as the subpixels 100 of the magnetic display panel illustrated in FIG. 12. That is, one subpixel 100a or 100b of the first and second magnetic display panels may be disposed to face the rear substrates 110a and 110b, the front substrates 140a and 140b, and the rear substrates 110a and The magnetic material layers 130a and 130b filled between the 110b and the front substrates 140a and 140b, the subpixel electrodes 120a and 120b partially formed on the inner surfaces of the back substrates 110a and 110b, and the front substrates 140a and 140b, respectively. The common electrodes 125a and 125b disposed on the inner surface of the 140b, the reflecting plates 131a and 131b disposed between the subpixel electrodes 120a and 120b and the magnetic material layers 130a and 130b, and the magnetic material layer Conductive spacers 123a and 123b disposed on side surfaces of the substrate 130a and 130b to seal the magnetic material layers 130a and 130b and electrically connect the subpixel electrodes 120a and 120b and the common electrodes 125a and 125b. It includes. The control circuits 160a and 160b, the outer walls 170a and 170b, the partition walls 175a and 175b, and the conductive spacers 123a and 123b are disposed between the front substrates 140a and 140b and the common electrodes 125a and 125b, respectively. Black matrices 150a and 150b are formed in the region facing the. In this case, however, the back substrates 110a, 110b, and 110 must be made of a transparent material.

In addition, although the reflective plate 131 used in the subpixel 100 of the magnetic display panel of FIG. 12 is a conventional non-active reflector rather than an active reflector, the reflective plate 131a of the subpixels of the double-sided magnetic display panel of FIGS. 20 and 21 is shown. 131b) uses an active reflector as shown in FIGS. 9 to 11. In this case, since the magnetic material layers 130a and 130b and the reflecting plates 131a and 131b are both applied with the magnetic field by the subpixel electrodes 125a and 125b, they are simultaneously turned on / off. Meanwhile, according to the present invention, the subpixels 100a and 100b of the first and second magnetic display panels may be individually turned on and off.

FIG. 22 is a cross-sectional view schematically illustrating an operation of a subpixel of the double-sided display panel illustrated in FIG. 20, and illustrates a case in which the subpixels 100a and 100b of the first and second magnetic display panels are both in an ON state. . Here, it is assumed that an external light source such as, for example, a sun or an indoor lamp is located on the subpixel 100a side of the first magnetic display panel.

When both of the subpixels 100a and 100b of the first and second magnetic display panels are in an ON state, the magnetic material layers 130a and 130b both transmit light of the S polarization component and reflect light of the P polarization component, The reflecting plates 131a and 131b both act as lenses for the light of the S polarization component and act as reflecting plates for the light of the P polarization component. To this end, the refractive indexes of the magnetic material layers 130a and 130b and the reflecting plates 131a and 131b should be different from each other. This may be achieved using other materials as the transparent medium of the magnetic material layers 130a and 130b and the reflecting plates 131a and 131b, and the magnetic material layer even when the magnetic material layers 130a and 130b are given a color filter function. The refractive indices of the 130a and 130b and the reflecting plates 131a and 131b may vary.

First, among the light emitted from the backlight unit 200, the light of the S-polarized component passes through the reflecting plates 131a and 131b and the magnetic material layers 130a and 130b to allow the sub-pixels 100a and 1 of the first and second magnetic display panels to pass through. Contribute to image formation of 100b). The light of the P polarization component repeats reflection between the two reflecting plates 131a and 131b. In this case, when the diffusion plate is provided inside the backlight unit 200, part of the light of the P-polarized component is changed to light in a non-polarized state, and thus finally, all the light emitted from the backlight unit 200 is used for image formation. Can be.

On the other hand, the external light S of the S-polarized component incident on the magnetic material layer 130a through the front substrate 140a of the sub-pixel 100a of the first magnetic display panel passes through the magnetic material layer 130a as it is. . Subsequently, the external light S of the S-polarized component is converged by the reflecting plates 131a and 131b, and then passes through the magnetic material layer 130b of the sub-pixel 100b of the second magnetic display panel, and thereby the second magnetic display. Contributes to the image formation of the sub-pixels 100b of the panel. On the other hand, the external light P of the P polarization component incident on the magnetic material layer 130a through the front substrate 140a of the sub-pixel 100a of the first magnetic display panel is reflected by the magnetic material layer 130a. . The external light P of the reflected P polarization component may be absorbed by, for example, an absorption type polarizing plate.

FIG. 23 is a cross-sectional view schematically illustrating an operation of a subpixel of the double-sided display panel illustrated in FIG. 20, wherein the subpixel 100a of the first magnetic display panel is in an ON state and the subpixel 100b of the second magnetic display panel is shown. Shows the case in the OFF state. Here too, it is assumed that an external light source, such as a sun or an indoor lamp, is on the subpixel 100a side of the first magnetic display panel.

In this case, a part of the light of the S-polarized component among the light emitted from the backlight unit 200 passes through the first reflecting plate 131a and the first magnetic material layer 130a to sub-pixel 100a of the first magnetic display panel. Contributes to the image formation. After the remaining part of the light of the S polarization component is reflected by the second reflecting plate 131b, the sub-pixels of the first magnetic display panel may also pass through the first reflecting plate 131a and the first magnetic material layer 130a. Contributes to the image formation of 100a). Light of the P polarization component repeats reflection between the first and second reflecting plates 131a and 131b. In this case, when the diffusion plate is provided inside the backlight unit 200, a part of the light of the P polarization component is changed to the light in the unpolarized state, so that finally all the light emitted from the backlight unit 200 is displayed in the first magnetic display. It may be used to form an image of the sub-pixel 100a of the panel.

In addition, the external light S of the S-polarized component incident on the first magnetic material layer 130a through the front substrate 140a of the sub-pixel 100a of the first magnetic display panel is the first magnetic material layer 130a. After passing through the first reflecting plate 131a, the light is reflected by the second reflecting plate 131b and passes through the first magnetic material layer 130a again. Therefore, the external light S of the S-polarized component contributes to the image formation of the sub-pixel 100a of the first magnetic display panel. On the other hand, the external light P of the P polarization component incident on the magnetic material layer 130a through the front substrate 140a of the sub-pixel 100a of the first magnetic display panel is reflected by the magnetic material layer 130a. . As described above, the external light P of the reflected P polarization component may be absorbed by, for example, an absorption type polarizing plate.

However, as described with reference to FIG. 22, when both of the subpixels 100a and 100b of the first and second magnetic display panels are in an ON state and the external light is located only on one of the magnetic display panels, the external light is It only contributes to the image formation of the sub-pixels of the opposite magnetic display panel. FIG. 24 illustrates an embodiment and operation for allowing external light to contribute to image formation of both subpixels of two magnetic display panels. As magnified below in FIG. 24, in the present exemplary embodiment, the reflecting plate 131a of the sub-pixel 100a of the first magnetic display panel is alternately arranged with the active reflecting plate 131a_a and the inactive reflecting plate 131a_i. It is a composite reflector. In addition, although not shown, the reflecting plate 131b of the sub-pixel 100b of the second magnetic display panel is also a composite reflector in which an active reflector and an inactive reflector are mixed.

FIG. 25 is a diagram for separately describing only the action of the composite reflector on external light. Referring to FIG. 25, the two reflectors 131a and 131b are composite reflectors having both active reflectors 131a_a and 131b_a and inactive reflectors 131a_i and 131b_i, and the active reflectors 131a_a and 131b_a face each other and are inactive. The reflecting plates 131a_i and 131b_i are disposed to face each other. When the two active reflectors 131a_a and 131b_a are both in the ON state and the external light source is located toward the first reflector 131a, some of the external light is reflected by the inactive reflector 131a_i of the first reflector 131a. The remaining part passes through both the first and second active reflectors 131a_a and 131b_a. Therefore, the external light may be evenly distributed to the first reflecting plate 131a and the second reflecting plate 131b.

Referring again to FIG. 24, when the subpixels 100a and 100b of the first and second magnetic display panels are both in the ON state, the light emitted from the backlight unit 200 is, as described with reference to FIG. 22, Contributes to image formation of the subpixels 100a and 100b of the first and second magnetic display panels. In addition, the external light S of the S-polarized component incident on the magnetic material layer 130a through the front substrate 140a of the sub-pixel 100a of the first magnetic display panel passes through the magnetic material layer 130a. . A part of the external light S of the S-polarized component passing through the magnetic material layer 130a is reflected by the inactive reflector 131a_i to contribute to the image formation of the sub-pixel 100a of the first magnetic display panel. The remaining portion of the external light S of the S-polarized component passing through the magnetic material layer 130a is converged by the first and second active reflecting plates 131a_a and 131b_a and then sub-pixels of the second magnetic display panel. Passing through the magnetic material layer 130b of (100b), it contributes to the image formation of the sub-pixel (100b) of the second magnetic display panel.

FIG. 26 is a cross-sectional view schematically illustrating an operation of a subpixel of the double-sided magnetic display panel illustrated in FIG. 21, and illustrates a case where both of the subpixels 100a and 100b of the first and second magnetic display panels are in an ON state. have. Here, it is assumed that an external light source such as a sun or an indoor lamp is on the side of the first magnetic display panel. The double-sided magnetic display panel shown in FIG. 21 uses only external light purely without the backlight unit. Accordingly, in order to distribute the external light evenly to the sub-pixels 100a and 100b of the first and second magnetic display panels in the double-sided magnetic display panel shown in FIG. 21, as described above, the reflecting plates 131a and 131b are It is preferable that it is a composite reflector having an active reflector 131a_a, 131b_a and an inactive reflector 131a_i, 131b_i.

In this case, referring to FIG. 26, the external light S of the S-polarized component incident on the magnetic material layer 130a through the front substrate 140a of the sub-pixel 100a of the first magnetic display panel is the magnetic material as it is. Pass through layer 130a. A part of the external light S of the S-polarized component passing through the magnetic material layer 130a is reflected by the inactive reflector 131a_i to contribute to the image formation of the sub-pixel 100a of the first magnetic display panel. Then, the remaining part of the external light S of the S-polarized component passing through the magnetic material layer 130a is converged by the active reflection plates 131a_a and 131b_a, and then the sub-pixel 100b of the second magnetic display panel is Passing through the magnetic material layer 130b may contribute to image formation of the sub-pixel 100b of the second magnetic display panel.

Meanwhile, the present invention can be applied not only to rigid flat display panels that are not bent, but also to flexible display panels that can be easily bent. In the case of the conventional liquid crystal display panel, since a high temperature process is required during a manufacturing process, the flexible substrate which is weak at high temperature cannot be used, and application to the flexible display was difficult. However, since the magnetic material layer 130, which is the core of the present invention, can be manufactured by a low temperature process of about 130 degrees, the magnetic material layer 130 can be applied to manufacturing a flexible display panel.

In order to apply the magnetic display panel according to the present invention to a flexible display panel, the components must be made of a flexible material. For example, referring to FIG. 12, as the material of the back and front substrates 110 and 140, transparent resin materials such as polyethylene naphthalate (PEN), polycarbonate (PC) and polyethylene terephthalate (PET) may be used. In addition, as the subpixel electrode 120 and the common electrode 125, for example, a conductive polymer material such as iodine-doped polyacetylene may be used. Iodine-doped polyacetylene is not used in conventional liquid crystal display panels because its conductivity is very high, similar to silver, but opaque. However, as described above, in the present invention, the subpixel electrode 120 and the common electrode 125 do not necessarily need to be transparent. In addition, in the case of the control circuit 160, a well-known organic TFT which is mainly used in a conventional flexible organic EL display (or flexible OLED display) can be used.

The backlight unit may also be configured by using the flexible light guide plate made of the above-described flexible light-transmissive material in the case of the edge type backlight unit, and may be configured by arranging light sources on the flexible substrate in the case of the direct backlight unit. In addition, when the magnetic display panel according to the present invention is applied to a paper like flexible display that can be viewed and discarded once like a newspaper, a glow material may be used as a light source instead of a backlight unit. For example, a luminous material such as copper-activated zinc sulfide (ZnS: Cu) or copper and magnesium activated zinc sulfide (Mg) may be used as a light source instead of a backlight.

In addition, even if an inorganic TFT is used instead of the organic TFT, it is possible to implement a flexible display. Since the inorganic thin film transistor has a hard structure and a high temperature process is required, separate flexible transistors and a control unit are manufactured by separating only the transistor part in the subpixel structure. FIG. 27 shows one sub-pixel 100 'of such a flexible magnetic display panel. The subpixel 100 ′ of the flexible magnetic display panel illustrated in FIG. 27 differs from the subpixel 100 of the magnetic display panel illustrated in FIG. 12 when the control circuit 160 is removed in the subpixel. have. The rest of the configuration of the subpixel 100 ′ of the flexible magnetic display panel illustrated in FIG. 27 is the same as that of the subpixel 100 of the magnetic display panel illustrated in FIG. 12. The flexible materials described above are used as materials for the back and front substrates 110 and 140, the subpixel electrode 120, and the common electrode 125.

According to the present embodiment, as shown in FIG. 28, the controller 30 made of inorganic thin film transistors for driving the respective subpixels and a separate control circuit 160 such as a transistor in the subpixels are removed. The flexible display unit 40 is provided. The controller 30 includes a plurality of inorganic thin film transistors corresponding to the respective subpixels, and includes a first connector 34 for connecting to the flexible display unit 40. The first connector 34 is electrically connected to the control side subpixel electrodes 33 extending from the drains of the plurality of inorganic thin film transistors and the control side common electrode 31 extending from the source. In addition, the flexible display unit 40 includes a second connector 41 coupled to the first connector 34 of the controller 30. The second connector 41 is electrically connected to the subpixel electrodes 120 and the common electrode 125 of the flexible display unit 40. Therefore, when the first connector 34 and the second connector 41 are coupled, it is possible to control ON / OFF of each subpixel in the flexible display unit 40 through the control unit 30.

To date, exemplary embodiments have been described and illustrated in the accompanying drawings in order to facilitate understanding of the present invention. However, it should be understood that such embodiments are merely illustrative of the invention and do not limit it. And it is to be understood that the invention is not limited to the illustrated and described description. This is because various other modifications may occur to those skilled in the art.

1 shows a schematic structure of an active reflector according to the invention.

FIG. 2 is a cross-sectional view of the active reflector shown in FIG. 1.

FIG. 3 shows an exemplary structure of magnetic particles of core-shell type used in the magnetic material layer of the active reflector shown in FIG. 1.

4 schematically shows a case where the active reflector according to the present invention is in the OFF state.

5 schematically shows a case where the active reflector according to the present invention is in the ON state.

6 and 7 are graphs showing transmission of a magnetic field in an active reflector according to the present invention.

8A and 8B exemplarily illustrate another structure of the magnetic material layer of the active reflector according to the present invention.

9 to 11 are cross-sectional views showing the surface shape of the active reflector according to the present invention and various magnetic field applying methods.

12 is a cross-sectional view schematically showing the structure of one sub-pixel of the magnetic display panel using the principle of an active reflector according to the present invention.

FIG. 13 exemplarily illustrates structures of a subpixel electrode, a conductive spacer, and a common electrode of one subpixel of the magnetic display panel according to the present invention shown in FIG. 12.

Fig. 14A schematically shows the magnetic field distribution formed around the wire of the subpixel electrode.

14B is a cross-sectional view illustrating a cross-sectional structure of a subpixel electrode, a magnetic material layer, and a common electrode cut along the line AA ′ of FIG. 13.

FIG. 15 schematically illustrates a structure of a subpixel array and a common electrode of a magnetic display panel according to an exemplary embodiment of the present invention.

FIG. 16 schematically illustrates a subpixel arrangement and a structure of a common electrode of a magnetic display panel according to another exemplary embodiment of the present invention.

FIG. 17 schematically illustrates a subpixel arrangement and a structure of a common electrode of a magnetic display panel according to another exemplary embodiment of the present invention.

18 is a cross-sectional view schematically showing the operation when the sub-pixel of the magnetic display panel according to the present invention is in the OFF state.

19 is a cross-sectional view schematically showing the operation when the sub-pixel of the magnetic display panel according to the present invention is in the ON state.

20 is a cross-sectional view illustrating a schematic structure of a subpixel of a double-sided magnetic display panel according to an embodiment of the present invention.

21 is a cross-sectional view illustrating a schematic structure of a subpixel of a double-sided magnetic display panel according to another embodiment of the present invention.

22 is a cross-sectional view schematically showing an operation when both sub-pixels of the double-sided magnetic display panel shown in FIG. 20 are in an ON state.

FIG. 23 is a cross-sectional view schematically illustrating an operation when one subpixel of the double-sided magnetic display panel shown in FIG. 21 is in an ON state and the other subpixel is in an OFF state.

FIG. 24 is a cross-sectional view schematically illustrating an operation of using a composite reflector in which an active reflector and an inactive reflector are mixed in one subpixel of the double-sided magnetic display panel shown in FIG. 20.

FIG. 25 illustrates the reflection / transmission principle of the composite reflector of FIG. 24.

FIG. 26 is a cross-sectional view schematically illustrating an operation when both sub-pixels of the double-sided magnetic display panel shown in FIG. 21 are in an ON state.

27 is a schematic cross-sectional view of a subpixel structure of the magnetic display panel according to another exemplary embodiment of the present invention.

28 is a conceptual diagram schematically illustrating a connection structure between a controller and a display unit.

※ Explanation of code about main part of drawing ※

10 .... active reflector 11 .... transparent board

12 .... magnetic material layer 13 .... magnetic particles

14 .... color absorbing particles 15 ...... transparent media

16 ... wire 18 ... transparent material layer

30 .... Control section 34, 41 .... Connector

40 .... flexible display unit

100 .... one subpixel on the magnetic display panel

110,140 ... substrate 120 .... subpixel electrode

121,126,127 .... hole 122 .... wire

123 .... conductive spacer 125 .... common electrode

130 .... magnetic layer 131 .... reflective plate

150 .... black matrix 160 ... control circuit

170 .... Outer wall 175 .... Bulk

200 .... Backlight Unit 300 .... Magnetic Display Panel

Claims

A magnetic material layer having magnetic particles embedded in a transparent insulating medium, wherein the light incident surface of the magnetic material layer has a convex parabolic shape having a symmetry axis in the center and a focus on the symmetry axis of the center plane. And an array of hybrid curved surfaces comprising a circumferential surface in the form of a concave parabolic surface extending from the surface.

The method of claim 1,

The magnetic material layer reflects all light unless an external magnetic field is applied, and transmits light in a first polarization direction when the external magnetic field is applied, and reflects light in a second polarization direction perpendicular to the first polarization direction. Active reflector.

The method of claim 1,

The thickness of the magnetic material layer is an active reflection plate, characterized in that greater than the magnetic attenuation length of the magnetic material layer.

The method of claim 1,

The magnetic material layer is an active reflector, characterized in that the magnetic particles of the core-shell structure and the color absorbing particles of the core-shell structure are mixed and distributed in one medium.

The method of claim 4, wherein

And wherein the magnetic particles of the core-shell structure include a magnetic core made of a conductive magnetic body and an insulating shell around the magnetic core.

The method of claim 5, wherein

And the insulating shell is made of a transparent insulating material surrounding the magnetic core.

The method of claim 5, wherein

And said insulating cell comprises a transparent insulating surfactant in the form of a polymer surrounding said magnetic core.

The method of claim 5, wherein

An active reflector, wherein one magnetic core forms one single magnetic domain.

The method of claim 5, wherein

The conductive magnetic body forming the magnetic core is cobalt, iron, iron oxide, nickel, Co-Pt alloy, Fe-Pt alloy, titanium, aluminum, barium, platinum, sodium, strontium, magnesium, dysprosium, manganese, gadolinium, silver , An active reflector comprising any one material selected from copper and chromium or an alloy thereof.

The method of claim 5, wherein

When the magnetic attenuation length of the magnetic core is s at the wavelength of incident light and the diameter of the magnetic core is d, the number n of magnetic cores required along the path of light traveling in the thickness direction of the inside of the magnetic material layer is

n ≥ s / d

An active reflector, characterized in that.

The method of claim 4, wherein

The size of the color absorbing particles is an active reflector, characterized in that less than or equal to the size of the magnetic particles.

The method of claim 4, wherein

The color absorbing particles of the core-shell structure is an active reflection plate, characterized in that consisting of a core made of a dielectric and a shell made of a metal.

The method of claim 12,

An active reflection plate, characterized in that the color absorbing particles having a different radius ratio of the core and the shell are distributed in the magnetic material layer.

The method of claim 1,

The magnetic material layer is formed by immersing magnetic particles having a core-shell structure in a solution together with a dye, and then coating and curing the magnetic particles on a transparent substrate.

The method according to any one of claims 1 to 14,

And magnetic field applying means for applying a magnetic field to the magnetic material layer, wherein the magnetic field applying means provides a plurality of wires arranged in parallel with each other around the magnetic material layer and a power source for providing a current to the plurality of wires. An active reflector comprising a.

The method of claim 15,

And the wires are arranged to surround a circumference of the magnetic material layer.

The method of claim 15,

And the wires are disposed on any one of an upper surface and a lower surface of the magnetic material layer.

The method of claim 15,

The wire is an active reflector, characterized in that made of any one material selected from ITO, aluminum, copper, silver, platinum, gold and iodine doped polyacetylene.

The method according to any one of claims 1 to 14,

Magnetic field applying means for applying a magnetic field to the magnetic material layer, wherein the magnetic field applying means includes a plate-shaped transparent electrode disposed on the surface of the magnetic material layer and a power source for supplying current to the transparent electrode. An active reflector characterized in that.

The method of claim 19,

The plate-shaped transparent electrode is an active reflector, characterized in that made of a conductive metal having a thickness thinner than ITO or surface depth.

A magnetic material layer that transmits light when an external magnetic field is applied and does not transmit light when an external magnetic field is not applied;

A reflector disposed under the magnetic material layer to reflect light transmitted through the magnetic material layer;

A first electrode disposed below the reflector;

A second electrode disposed on the magnetic material layer; And

And a spacer disposed on a side of the magnetic material layer to electrically connect the first electrode and the second electrode.

And a dye or color absorbing particles are mixed in the magnetic material layer.

The method of claim 21,

The magnetic material layer transmits light in a first polarization direction when an external magnetic field is applied, reflects light in a second polarization direction perpendicular to the first polarization direction, and reflects all light when no external magnetic field is applied. Magnetic display pixel.

The method of claim 21,

The magnetic material layer is a magnetic display pixel, characterized in that the magnetic particles are embedded in a transparent insulating medium without agglomeration with each other.

The method of claim 23,

And a thickness of the magnetic material layer is greater than a magnetic attenuation length of the magnetic material layer.

The method of claim 23,

The magnetic material layer is a magnetic display pixel, characterized in that the magnetic particles of the core-shell structure and the color absorbing particles are mixed and distributed in one medium.

The method of claim 25,

The magnetic particle of the core-shell structure includes a magnetic core made of a conductive magnetic body and an insulating shell around the magnetic core.

The method of claim 26,

And the insulating cell is made of a transparent insulating surfactant in the form of a polymer surrounding the magnetic core.

The method of claim 26,

A magnetic display pixel, wherein one magnetic core forms one single magnetic domain.

The method of claim 26,

The conductive magnetic body forming the magnetic core is cobalt, iron, iron oxide, nickel, Co-Pt alloy, Fe-Pt alloy, titanium, aluminum, barium, platinum, sodium, strontium, magnesium, dysprosium, manganese, gadolinium, silver And a material selected from the group consisting of copper and chromium or an alloy thereof.

The method of claim 26,

n ≥ s / d

The magnetic display pixel which is characterized by the above-mentioned.

The method of claim 25,

And the size of the color absorbing particles is less than or equal to the size of the magnetic particles.

The method of claim 25,

And the color absorbing particles are formed of a core made of a dielectric and a shell made of a metal.

The method of claim 33, wherein

And color absorbing particles having different radius ratios of a core and a shell from each other in the magnetic material layer.

The method of claim 21,

The magnetic material layer is formed by immersing magnetic particles having a core-shell structure in a solution together with a dye and then curing the magnetic display pixel.

The method of claim 21,

And a transparent front substrate disposed on the first electrode and a rear substrate disposed on the second electrode.

The method of claim 36,

And an antireflective coating formed on at least one of the optical surfaces from the magnetic material layer to the outer surface of the front substrate.

The method of claim 36,

And an absorption type polarizer disposed on any one of the optical surfaces from the magnetic material layer to the outer surface of the front substrate.

The method of claim 21,

The reflecting surface of the reflector has an array of hybrid curved surfaces comprising a convex parabolic surface having a central axis of symmetry and a concave parabolic surface extending from the center surface with a focus on the axis of symmetry of the central surface. Magnetic display pixel, characterized in that.

The method according to any one of claims 21 to 39,

And the first electrode, the second electrode, and the conductive spacer are made of any one of aluminum, copper, silver, platinum, gold, and iodine-doped polyacetylene.

The method of claim 40,

In order to allow light to pass through the first electrode, a plurality of first holes are formed in the first electrode, and a plurality of wires extending in a direction in which current flows are formed between the first holes. Magnetic display pixel.

42. The method of claim 41 wherein

And a light-transmissive material is formed in the first hole region between the wires.

The method of claim 40,

And a second hole formed in a region of the second electrode that faces the magnetic material layer so that light can pass through the second electrode.

The method of claim 43,

A light transmissive material is formed in the second hole region of the second electrode.

The method of claim 40,

The second electrode is a magnetic display pixel, characterized in that the wire of the mesh or grid structure electrically connected to the conductive spacer.

The method according to any one of claims 21 to 39,

And the first electrode and the second electrode are made of a transparent conductive material.

39. The method of any of claims 21-38,

And a control circuit disposed on a side of the magnetic material layer, and configured to switch a current flow between the first electrode and the second electrode.

The method of claim 47,

And a black matrix disposed on an area of the upper surface of the second electrode that faces the control circuit and the conductive spacer.

36. A magnetic display panel comprising a plurality of magnetic display pixels according to any one of claims 21 to 35.

The method of claim 49,

The magnetic display panel further comprises a transparent front substrate disposed on the first electrode and a back substrate disposed on the second electrode.

51. The method of claim 50,

The method of claim 49,

The reflecting surface of the reflector has an array of hybrid curved surfaces comprising a convex parabolic surface having a central axis of symmetry and a concave parabolic surface extending from the center surface with a focus on the axis of symmetry of the central surface. Magnetic display panel, characterized in that.

The method of claim 49,

The method of claim 54, wherein

In order to allow light to pass through the first electrode, a plurality of first holes are formed in the first electrode, and a plurality of wires extending in a direction in which current flows are formed between the first holes. Magnetic display panel.

The method of claim 55,

And a light-transmissive material is formed in the first hole area between the wires.

The method of claim 54, wherein

The method of claim 57,

A light transmissive material is formed in the second hole area of the second electrode.

The method of claim 54, wherein

The second electrode is a magnetic display panel, characterized in that the wire of the mesh or grid structure electrically connected to the conductive spacer.

The method of claim 49,

And a control circuit disposed on a side of the magnetic material layer, the control circuit switching a current flow between the first electrode and the second electrode.

62. The method of claim 61,

51. The method of claim 50,

The magnetic display panel is a flexible display panel comprising a flexible material of the front substrate, the back substrate, the first electrode and the second electrode.

The method of claim 63, wherein

And the front and back substrates are made of a transparent resin material, and the first and second electrodes are made of a conductive polymer material.

The method of claim 53 wherein

And an organic thin film transistor disposed on a side of the magnetic material layer between the front substrate and the rear substrate, the organic thin film transistor switching a current flow between the first electrode and the second electrode.

The method of claim 63, wherein

The magnetic display panel includes a display unit in which a plurality of pixels are arranged, and a separate control unit for individually switching current flow between the first electrode and the second electrode for each pixel.

51. The method of claim 50,

A plurality of pixels share one common front substrate, back substrate, and second electrode, and a magnetic material layer and a first electrode for applying a magnetic field to the magnetic material layer are arranged one by one for each pixel. panel.

A double-sided display panel, wherein the first and second magnetic display panels having a plurality of magnetic display pixels according to any one of claims 21 to 39 are arranged in a symmetrical configuration while facing each other.

The method of claim 68, wherein

And a transparent rear substrate disposed between the first magnetic display panel and the second magnetic display panel.

The method of claim 69,

Reflectors of the first and second magnetic display panels are composite reflectors in which active reflectors and inactive reflectors are alternately arranged. The active reflector includes a magnetic material layer in which magnetic particles are embedded in a transparent insulating medium, and an external magnetic field. If not applied, reflects all light, and if an external magnetic field is applied, transmits light in a first polarization direction and reflects light in a second polarization direction perpendicular to the first polarization direction.

The method of claim 69,

And a backlight unit further disposed between the first magnetic display panel and the second magnetic display panel.

40. An electronic device employing a magnetic display panel having a plurality of magnetic display pixels according to any one of claims 21 to 39.