JP2006010851A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device which effectively cools the image display medium, without increase in the weight or in size, and which is prevented from deteriorating in the display quality. <P>SOLUTION: A transparent plate 13 is fitted to the front of the body 12 of the image display device 1, and the image display medium 100, where an image can be written by applying a voltage and can be displayed without power source is fitted in a longitudinal position to the transparent plate 13 at a prescribed interval. A cavity part 14, where outside air can flow is formed of the gap formed between the transparent plate 13 and image display medium 100, and by flowing air in the cavity part 14, the image display medium 100 is cooled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device including an image display medium in which an image is written by application of a voltage and can be displayed without a power source, and in particular, cooling of the image display medium is effective without causing an increase in weight and an increase in size. The present invention relates to an image display apparatus that can be performed automatically and prevents deterioration in display quality.

  Conventionally, a liquid crystal display or a plasma display is used as a flat type display device. However, since these have no memory property, the display contents are lost when the power is turned off. In view of this, an image display medium has been proposed that has a memory property and that allows the display contents to be viewed without applying a power supply once the image is written to the image display medium.

  As such a conventional image display medium, for example, a toner-type image display medium that performs image display by moving colored particles by an electric field is known (for example, see Patent Document 1).

  The image display medium has a translucent surface substrate in which column electrodes formed on a surface substrate member are protected by a dielectric film, and a back surface in which row electrodes formed on the back substrate member are protected by a dielectric film. A substrate, a partition member that forms a plurality of cells by partitioning the substrates in a direction parallel to the substrate, and a negatively charged white particle group and a positively charged black particle A group is enclosed in each cell.

  In this image display medium, when a DC voltage is applied between the row electrode and the column electrode, an electric field is formed in the pixel between the electrodes, and white particles and black particles move toward the front substrate or the rear substrate depending on the direction of the electric field. Due to the contrast between the white particles and the black particles that have moved and adhered to the inner surface of the surface substrate, black and white image display is performed through the surface substrate. According to this configuration, since the display does not disappear unless the electric field is changed, the image can be held without a power source after the image is written.

  When an image display device having such an image display medium is installed outdoors and used for an advertising tower, a signboard, etc., the image display medium, internal circuits, etc. are affected by the ambient temperature. The temperature rises markedly compared to. In particular, the particles have a sealed structure in order to avoid the influence of moisture and the like and to prevent the particles from scattering, and the temperature of the particles is likely to rise. In particular, black particles easily absorb heat, and a change in voltage threshold due to a change in particle charging characteristics due to a temperature rise causes density defects, image defects, and the like, and display quality deteriorates. In addition, the particle charging characteristics change depending on the outgas generated from the adhesive, the substrate, and the like. Furthermore, when the temperature in the housing rises, the operation of the LSI mounted on the control circuit board or the like tends to become unstable.

  On the other hand, Patent Document 2 discloses a cooling device that has a high possibility of using an image display medium, a control circuit board, and the like for cooling.

In the cooling device described in Patent Document 2, a flow path having an intake port and an exhaust port is piped in the apparatus, an electronic component is brought into close contact with the outer peripheral surface of the pipe, and a temperature difference between the inner surface and the outer surface of the pipe is caused. A structure for generating an air flow from the intake port to the exhaust port in the pipe, and heat of the air in the flow path is converted into electric energy by an energy converter, and a fan provided at the exhaust port is rotated by this electric energy, It has a configuration to dissipate heat from the electronic component.
Japanese Patent Laying-Open No. 2002-99002 ([0008], FIG. 23, FIG. 24) JP 2003-249612 A ([0028] to [0032], [0042] to [0044], FIGS. 1 and 8)

  However, according to the conventional image display device, when the cooling device as described in Patent Document 2 is applied, the image display medium has a large surface area, and thus the size of the pipe becomes extremely large. Since a metal must be used, an increase in weight and size is inevitable.

  Accordingly, an object of the present invention is to provide an image display apparatus that can effectively cool an image display medium without causing an increase in weight and an increase in size, and that prevents deterioration in display quality.

  In order to achieve the above-described object, the present invention achieves the above-described object, and an image is written by applying a voltage and an image display medium capable of displaying by a non-power source; A circuit unit that is provided in the main body and applies the voltage to the image display medium; and provided on a front surface or a rear surface of the image display medium, having an intake port on a lower side and an exhaust port on an upper side; There is provided an image display device comprising a cavity capable of circulating outside air from the opening toward the exhaust port.

  According to the image display device of the present invention, the heat generated by the image display medium and the circuit can be radiated to the outside through the cavity, so that the image display medium can be effectively cooled without increasing the weight or size. Thus, it is possible to prevent display quality from deteriorating.

[First Embodiment]
FIG. 1 shows an image display apparatus according to a first embodiment of the present invention. The image display device 1 includes a stand 11, a box-shaped main body 12 attached to the stand 11, a transparent plate 13 made of glass or plastic that is attached to the front surface of the main body 12 and functions as a protective cover, and a transparent plate 13 includes an image display medium 100 erected in a vertical position in the main body 12 through a cavity 14 secured by a spacer (not shown) on the back surface of the image display medium 13, a power supply circuit, a control circuit, a display drive circuit, and the like. Circuit unit 15 disposed adjacent to 100, air intake fan 16 disposed in the vicinity of air inlet 14 a at the bottom of cavity 14, and air outlet 14 b in the upper portion of cavity 14. And an exhaust fan 17.

(Layer structure of image display medium)
FIG. 2 shows a layer structure of the image display medium 100. The image display medium 100 includes a pair of transparent substrates 101A and 101B arranged at a predetermined interval, a row electrode 102 arranged inside the substrate 101A using ITO (indium tin oxide), and ITO. The column electrode 103 disposed inside the substrate 101B, the dielectric layers 104A and 104B disposed inside the row electrode 102 and the column electrode 103, the dielectric layer 104A and the dielectric layer 104B, respectively. A space portion 105 formed therebetween, and white particles 106A and black particles 106B enclosed in the space portion 105 are provided. Each of the row electrode 102 and the column electrode 103 is composed of a plurality of electrodes and is arranged in a matrix. The dielectric layers 104A and 104B are made of polycarbonate, polyester, polyimide, epoxy, or the like, and are provided to protect the row electrodes 102 and the column electrodes 103 and to stabilize the charging characteristics of the particles. Note that the column electrode 103 may be provided over the substrate 101A and the row electrode 102 may be provided over the substrate 101B.

  The white particles 106A can be obtained, for example, by externally adding 0.4 parts by weight of titania fine powder treated with isopropyltrimethoxysilane to 100 parts by weight of spherical fine particles of titanium oxide-containing crosslinked polymethyl methacrylate having a volume average particle size of 20 μm. Can do. Further, for example, spherical fine particles of carbon-containing crosslinked polymethyl methacrylate having a volume average particle diameter of 20 μm can be used as the black particles 106B.

(Operation of image display device)
Next, the operation of the image display device 1 will be described. When the power is turned on, a control circuit (not shown) in the circuit unit 15 enables writing of an image on the image display medium 100 and drives the intake fan 16 and the exhaust fan 17 to evacuate the outside air from the direction A. The air is sucked into the part 14. The air sucked into the cavity 14 rises up the flow path 14c of the cavity 14 and reaches the upper part, and is exhausted from the direction B to the atmosphere by the exhaust fan 17. The surface of the image display medium 100 facing the cavity portion 14 is cooled by the air flowing through the cavity portion 14, so that an increase in temperature of the image display medium 100 due to solar heat or heat generation in the main body 12 is suppressed.

(Write operation to image display media)
Next, an image writing operation to the image display medium 100 will be described. When writing to the image display medium 100, a predetermined voltage is applied to the row electrode 102 and the column electrode 103 that intersect pixel portions corresponding to image data. For example, a voltage of 0V is applied to the row electrode 102, and a positive or negative image voltage of, for example, about + 140V or −140V is applied to the column electrode 103 according to the image data for a predetermined time (for example). For example, 30 ms) is applied.

  The white particles 106A and the black particles 106B are charged to different polarities by frictional charging. For example, the white particles 106A are negatively charged and the black particles 106B are positively charged. When a voltage is applied to the row electrode 102 and the column electrode 103 based on the image data, the negatively charged white particles 106A move to the column electrode 103 side to which a positive voltage is applied and adhere to the inner surface of the dielectric layer 104B. The positively charged black particles 106B adhere to the inner surface of the dielectric layer 104A on the row electrode 102 side. In this way, the black and white image formed by the white particles 106A and the black particles 106B attached to the row electrode 102 side sees the display light 111 from the direction of the line of sight E through the substrate 101A when the illumination light 110 is irradiated. be able to.

  Even if the application of voltage to the row electrode 102 and the column electrode 103 is stopped, the electrostatic adhesion force between the white particles 106A and the black particles 106B and the dielectric layers 104A and 104B is maintained, so that the particles 106A and 106B. Is held attached to the inner surfaces of the dielectric layers 104A and 104B, and a black and white image is displayed for a long time.

(Effects of the first embodiment)
According to the first embodiment, the following effects can be obtained.
(A) Since the image display medium 100 is cooled by the outside air flowing through the hollow portion 14, the temperature rise of the image display medium 100 is suppressed, and display quality deterioration can be prevented. Since the heat generation of the image display medium 100 can be suppressed, the temperature rise in the main body 12 is suppressed, so that the operation of the circuit unit 15 can be stabilized.
(B) Since the cavity 14 has a structure formed by the image display medium 100 and the transparent plate 13, it is not necessary to form a flow path by using a separate part such as a copper material for the cavity 14, resulting in an increase in weight and an increase in size. There is nothing.
(C) Since a predetermined gap is provided between the image display medium 100 and the transparent plate 13, it is possible to suppress the occurrence of Newton rings and prevent the display image from becoming difficult to see.

[Second Embodiment]
FIG. 3 shows an image display apparatus according to the second embodiment of the present invention. The present embodiment is characterized in that, in the first embodiment, a spacer 18B is provided between the transparent plate 13 and the circuit unit 15, and the cavity 14 is provided between the image display medium 100 and the circuit unit 15. Other configurations are the same as those of the first embodiment. The cooling operation by the cavity 14 is different from that of the first embodiment in that the image display medium 100 is cooled from the back surface.

  According to the second embodiment, since the image display medium 100 and the circuit unit 15 are in contact with the cavity 14, the image display medium 100 and the circuit unit 15 can be cooled at the same time. Therefore, the display defect of the image display medium 100 can be prevented and the circuit unit 15 can be cooled, so that the operation of the circuit unit 15 can be stabilized.

[Third Embodiment]
FIG. 4 shows an image display apparatus according to the third embodiment of the present invention. In the second embodiment, as shown in FIG. 4A, the cross-sectional area of the cavity portion 14 is increased and the radiator 19 is disposed in the cavity portion 14 in the second embodiment. Other configurations are the same as those of the second embodiment. As shown in FIG. 4 (b), the radiator 19 includes a large number of fins 19a made of a metal material having excellent thermal conductivity, such as copper and aluminum, and a flow path 14c from the intake port 14a to the exhaust port 14b. It is arranged in the horizontal direction while ensuring. In addition, you may arrange | position the many fins 19a to the orthogonal | vertical direction, ensuring the flow path 14c.

  According to the third embodiment, by providing the radiator 19 in the cavity portion 14, the heat exchange efficiency in the cavity portion 14 can be enhanced as compared with the second embodiment.

[Fourth Embodiment]
FIG. 5 shows an image display apparatus according to the fourth embodiment of the present invention. In the second embodiment, the heat blocking film 20 is attached to the back surface of the transparent plate 13 in the second embodiment, and other configurations are the same as those in the second embodiment.

  As the heat blocking film 20, for example, a film having a characteristic of transmitting visible light and blocking infrared light, such as an acetate film, can be used. Since this heat shielding film 20 has translucency, it can be disposed on the front side of the image display medium 100. The heat shield film 20 may be attached to the surface of the transparent plate 13 or the front surface of the image display medium 100.

  According to the fourth embodiment, since the heat blocking film 20 is adhered to the transparent plate 13, infrared rays included in solar heat are blocked by the heat blocking film 20 and hardly reach the image display medium 100. The temperature rise from the front side can be suppressed, and the temperature rise of the image display medium 100 can be reduced as compared with the second embodiment.

[Fifth Embodiment]
FIG. 6 shows an image display apparatus according to the fifth embodiment of the present invention. In the present embodiment, the heat blocking film 20 is attached to the surface of the image display medium 100 in the first embodiment, and other configurations are the same as those in the first embodiment.

  According to the fifth embodiment, since the heat blocking film 20 is attached to the surface of the image display medium 100, the infrared rays contained in the solar heat are blocked by the heat blocking film 20 and reach the image display medium 100. Therefore, the temperature rise from the front side can be suppressed, and the temperature rise of the image display medium 100 can be reduced as compared with the first embodiment.

[Sixth Embodiment]
FIG. 7 shows an image display apparatus according to the sixth embodiment of the present invention. In the fifth embodiment, a UV (ultraviolet) cut film 21 is attached to the back surface of the transparent plate 13 in the fifth embodiment, and other configurations are the same as those in the fifth embodiment. .

  According to the sixth embodiment, ultraviolet light is blocked by the UV cut film 21, and infrared rays contained in the solar heat are blocked by the heat blocking film 20, so that the temperature rise of the image display medium 100 is the fifth. This can be further suppressed than in the embodiment.

[Seventh Embodiment]
FIG. 8 shows an image display apparatus according to the seventh embodiment of the present invention. In this embodiment, in the second or fourth embodiment, the substrate 101B of the display recording medium 100 is provided with a plurality of recesses 112 extending in the horizontal direction at predetermined intervals in the vertical direction. This is the same as in the second or fourth embodiment. The recess 112 may be provided with a plurality of recesses extending in the vertical direction at predetermined intervals in the horizontal direction.

  According to the seventh embodiment, the recess 112 exposed in the cavity portion 14 functions as a heat radiating fin, and the image display medium 100 is effectively cooled. Therefore, the second and fourth embodiments. As compared with the above, the heat exchange efficiency of the image display medium 100 can be improved.

[Other embodiments]
Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention, and combinations of components can be arbitrarily performed between the embodiments. For example, although the hollow portion 14 is disposed at a position in contact with the image display medium 100, the hollow portion 14 may be provided on a back portion or the like in the main body 12. Moreover, although the intake fan 16 and the exhaust fan 17 are installed in the cavity 14, either one may be used. Moreover, although it was set as the structure which flows air up and down, you may make it the structure flowed in the left-right direction. Further, a temperature sensor may be installed inside the main body, and the intake fan or the exhaust fan may be driven when the temperature becomes higher than the set temperature, and stopped when the temperature becomes lower than the set temperature.

  Further, a heat insulating material may be provided between the image display medium 100 or the cavity 14 and the circuit unit 15. Thereby, it is possible to prevent heat generated in the circuit unit 15 from being transmitted to the image display medium 100.

  In addition to the above, as an image display medium having a memory property, a heat-sensitive recording medium using a leuco dye, a liquid crystal having a memory property represented by a ferroelectric liquid crystal, or a charged particle is moved to switch a display. Other image display media such as an electrophoresis system, a particle rotation system in which charged particles are rotated to switch the display, and a magnetophoresis system in which the particles are moved by magnetism to switch the display may be used.

1 is a cross-sectional view showing an image display device according to a first embodiment of the present invention. It is sectional drawing which shows the layer structure of the image display medium of FIG. It is sectional drawing which shows the image display apparatus which concerns on the 2nd Embodiment of this invention. (A) is sectional drawing which shows the image display apparatus concerning the 3rd Embodiment of this invention, (b) is principal part sectional drawing which shows the detail of a heat radiator. It is sectional drawing which shows the image display apparatus which concerns on the 4th Embodiment of this invention. It is sectional drawing which shows the image display apparatus which concerns on the 5th Embodiment of this invention. It is sectional drawing which shows the image display apparatus which concerns on the 6th Embodiment of this invention. It is sectional drawing which shows the image display apparatus which concerns on the 7th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display apparatus 11 Stand 12 Main body 13 Transparent plate 14 Cavity part 14a Inlet 14b Exhaust 14c Flow path 15 Circuit unit 16 Intake fan 17 Exhaust fan 19 Radiator 19a Fin 20 Heat blocking film 21 UV cut film 100 Image display medium 101A , 101B Substrate 102 Row electrode 103 Column electrode 104A, 104B Dielectric layer 105 Space 106A White particle 106B Black particle 110 Illumination light 111 Display light 112 Recess A Direction B Direction E Line of sight

Claims (11)

An image display medium in which an image is written by applying a voltage and can be displayed without a power source;
A main body that supports the image display medium in a posture different from a horizontal posture;
A circuit unit that is provided in the main body and applies the voltage to the image display medium;
Provided on the front surface or the rear surface of the image display medium, having an air intake port below, an air exhaust port above, and a cavity capable of circulating outside air from the air intake port toward the air exhaust port An image display device characterized by that.   The image display device according to claim 1, wherein the hollow portion is provided on the rear surface of the image display medium and between the image display medium and the circuit unit.   The image display device according to claim 1, wherein the hollow portion has a surface area that covers substantially the entire front surface or the rear surface of the image display medium.   The image display device according to claim 1, wherein the main body includes a fan in at least one of the intake port and the exhaust port.   The image display device according to claim 1, wherein the main body includes a radiator in the hollow portion.   The image display device according to claim 1, wherein the image display medium includes a transparent plate on the front surface through the cavity.   The image display device according to claim 6, wherein the main body includes a heat shielding film attached to a surface of the transparent plate or the image display medium.   The image display device according to claim 6, wherein the main body includes an ultraviolet cut film attached to a surface of the transparent plate or the image display medium.   The image display device according to claim 1, wherein the main body includes a heat insulating material between the image display medium or the cavity and the circuit unit. The image display medium has a plurality of concave portions or convex portions on the rear surface,
The image display device according to claim 1, wherein the hollow portion is provided on the rear surface of the image display medium. The image display device according to claim 1, wherein the image display medium is a toner system that displays an image by moving colored particles by an electric field.