JP2006010850A - Image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display apparatus wherein a display unit is effectively cooled to prevent the deterioration of the display quality of the display unit by a simple construction. <P>SOLUTION: The display unit 100 of a toner system is built in a main body 11 in a state in which a transparent plate 12 and an intermediate member 13 are disposed on its front and rear surfaces, respectively. In order to increase a heat radiation area, a material having excellent thermal conductivity is used for a rear member 11A of the main body 11 and a projecting and recessed part 11B is provided at a part of the rear member 11A. Similarly, a projecting and recessed part 13A is provided at a part of a rear surface of the intermediate member 13. Thermal conduction grease 15 for transmitting heat from the intermediate member 13 to the rear member 11A is packed between the projecting and recessed part 13A and rear member 11A. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device including a display unit in which an image is written by application of a voltage and can be displayed without a power supply, and in particular, the display unit is effectively cooled with a simple configuration to display the display unit. The present invention relates to an image display apparatus that prevents deterioration of quality.

  Conventionally, a liquid crystal display or a plasma display has been used as a flat type display device. However, since these devices do not have a memory property, display contents disappear 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 with no power supply 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 tend to absorb heat, and a change in threshold voltage due to a change in particle charging characteristics due to a temperature rise causes a density defect, an image defect, and the like, resulting in a deterioration in display quality. In addition, the particle charging characteristics change depending on the outgas generated from the adhesive, the substrate, and the like.

On the other hand, as a cooling device that is highly likely to be used for cooling an image display medium, a control circuit board, and the like, there is a cooling device that uses a heat pipe and attaches a power supply unit or the like to the heat pipe for cooling (for example, Patent Document 2) reference).
Japanese Patent Laying-Open No. 2002-99002 ([0008], FIG. 23, FIG. 24) JP-A-8-69254 ([0023], [0024], FIGS. 1 and 2)

  However, according to the conventional image display device, when a cooling device as described in Patent Document 2 is applied, cooling is performed even when the temperature is low and cooling is not necessary. Also, since the heat pipe has a small cooling area, it is not suitable for cooling an image display medium having a large surface area. Furthermore, it is necessary to draw at least one end of the heat pipe into the main body, which restricts the layout.

  Accordingly, it is an object of the present invention to provide an image display device that effectively cools a display unit and prevents deterioration in display quality of the display unit with a simple configuration.

  In order to achieve the above object, the present invention provides a display unit in which an image is written by applying a voltage and display without a power source is possible, and the display unit is sealed in a sealed space so that the display surface of the display unit can be visually recognized from the outside. And a heat-dissipating means for dissipating heat generated from the display unit to the outside of the housing via the contact member. An image display device is provided.

  According to the image display device of the present invention, the heat generated from the display unit is conducted to the contact member and dissipated to the outside, so that the display unit can be effectively cooled with a simple configuration, and the display quality can be improved. Deterioration can be prevented.

[First Embodiment]
FIG. 1 shows an image display apparatus according to a first embodiment of the present invention. This image display device 1 is arranged in a vertical posture so that the display surface faces the front, is made in a box shape using a material having excellent thermal conductivity such as metal, and the uneven portion 11B is formed on the back member 11A. A main body 11 serving as a housing, and a transparent plate 12 that is mounted on the front surface of the main body 11 and that functions as a protective cover and is made of transparent plastic, glass, etc., and forms a sealed space with the main body 11 and the back member 11A; A predetermined gap is formed between the display unit 100 installed on the back surface of the transparent plate 12, the intermediate member 13 as a close contact member in close contact with the back surface of the display unit 100, and the transparent plate 12 and the surface of the display unit 100. Spacers 14 that prevent the occurrence of Newton's rings, and a silica filled in a predetermined range between the intermediate member 13 and the back surface of the main body 11 so as to fill the uneven portion 13A. Positioning of the intermediate member 13, the heat conductive grease 15 as a heat transfer medium such as a grease, the power source / control unit 16 for performing display control of the display unit 100, the air flow path 17 installed on the outer surface of the back member 11 A Adjustment screws 18A and 18B used in the above.

  The back member 11A is made of a material having excellent thermal conductivity, such as copper and aluminum, and includes a concavo-convex portion 11B formed by providing long grooves in a direction perpendicular to the paper surface at regular intervals on the outside in order to improve heat dissipation efficiency. In addition, you may provide an uneven | corrugated | grooved part in the heat conductive grease 15 side. Thereby, the heat transfer efficiency from the heat conductive grease 15 can be increased.

  The main body 11 and the back member 11A may be made by weaving a material having high thermal conductivity, such as a metal wire, into a material such as plastic.

  The intermediate member 13 is made of a material having excellent thermal conductivity, such as copper and aluminum, and the uneven portion 13A is formed by providing long grooves in a direction perpendicular to the paper surface at a constant interval in a portion facing the uneven portion 11B of the back member 11A. Is provided.

  Radiating fins are formed by the uneven portions 11B and 13A provided on the back member 11A and the intermediate member 13. These concavo-convex portions 11B and 13A may be provided with grooves in a grid pattern to form concavo-convex portions.

  The air flow path 17 is attached to the outer surface of the back member 11A by attaching a heat radiating member 19 formed by bending or pressing a material having excellent thermal conductivity such as copper or aluminum into a “U” shape, and penetrating in the vertical direction. It is obtained by forming holes. An air intake port (not shown) is formed at the lower end portion of the through hole so as to take in outside air, and an exhaust port for exhausting internal heat is formed at the upper end portion of the through hole. In addition, a radiator or an electric fan may be attached to the air flow path 17, the air intake port, the exhaust port, or the surface of the heat radiating member 19 to form a forced air cooling configuration.

  The power supply / control unit 16 includes a control circuit, an image memory that stores write data, a display drive circuit that performs display drive, a communication interface, a power supply circuit that supplies DC power to each circuit and supplies pulse power to the display unit 100, etc. It is comprised including. The power supply circuit includes a rectifier circuit, a voltage regulator circuit for obtaining a stabilized voltage such as +5 V, +12 V, a pulse power supply circuit that generates a pulse voltage of about ± 140 V, and a battery. The power supply / control unit 16 may be provided outside the main body 11 or inside the main body 11.

  In addition, the structure which does not have the intermediate member 13 is also possible, and in this case, the heat conductive grease 15 is interposed between the back surface of the display unit 100 and the inner surface of the back member 11A.

(Configuration of display unit)
FIG. 2 shows a detailed configuration of the display unit 100 shown in FIG. The display unit 100 includes a pair of transparent substrates 101A and 101B disposed at a predetermined interval, a row electrode 102 disposed on the inner side of 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 black 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.

  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 with reference to FIG. 1 and FIG. First, when the power supply is turned on, power is supplied to the power supply circuit and pulse power supply circuit of the power supply / control unit 16. The predetermined DC voltage generated by the power supply circuit is supplied to a control circuit or the like in the power supply / control unit 16. The pulse voltage generated by the pulse power supply circuit is used as a pulse power supply when writing an image.

  When the image display device 1 is used outdoors on a sunny day, the temperature of the display unit 100 rises due to sunlight irradiated on the display surface, and the temperature is transferred to the back surface of the display unit 100 over time, and further to the middle. Heat is transferred to the member 13. Further, the heat of the intermediate member 13 is transferred to the back member 11 </ b> A through the heat conductive grease 15. Since the intermediate member 13 is provided with the concavo-convex portion 13A on the contact surface with the heat conductive grease 15, the contact area is increased and the thermal resistance of this portion can be reduced, so that the heat transfer efficiency is improved.

  In the back member 11A that functions as a heat sink, heat exchange with air in the atmosphere is performed in the concavo-convex portion 11B, the air flow path 17, and other flat portions. Since the portion where the concavo-convex portion 11B is formed has a larger heat radiation area than the plane portion, the heat from the thermal conductive grease 15 can be radiated more efficiently than the plane portion. Further, in the air flow path 17, the heat radiating member 19 functions as a heat sink, and air flows into the interior as the temperature in the heat radiating member 19 rises. It is cooled by air cooling.

(Write operation to the display unit)
Next, an image writing operation to the display unit 100 will be described. A predetermined voltage generated by the pulse power supply circuit of the power supply / control unit 16 is applied to the row electrode 102 and the column electrode 103 that intersect the pixel portion corresponding to the 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, 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 composed of 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 heat from the intermediate member 13 is transferred to the back member 11A via the thermal conductive grease 15, and further dissipated into the atmosphere via the air flow path 17 and the uneven portion 11B, the display unit 100 Temperature rise is suppressed, and display quality deterioration can be prevented.
(B) Since a predetermined gap is formed between the display unit 100 and the transparent plate 12 by the spacer 14, it is possible to suppress the occurrence of Newton rings and prevent the display image from being difficult to see.
(C) Since the intermediate member 13 and the back member 11A only include the thermal conductive grease 15, the depth of the storage portion of the display unit 100 can be reduced, and the image display device 1 can be thinned. Become.

[Second Embodiment]
FIG. 3 shows an image display apparatus according to the second embodiment of the present invention. In the first embodiment, the image display device 1 is formed by removing the concavo-convex portions 11B and 13A, the heat conductive grease 15 and the heat radiating member 19, and Peltier elements 20A to 20D as cooling means, and the Peltier elements. A plurality of thermal wirings 21 that form a heat conduction path between 20A to 20D and the back member 11A and a power supply unit 22 that supplies power to the Peltier elements 20A to 20D are provided. This is the same as the embodiment. The power supply unit 22 may be included in the power supply circuit of the power supply / control unit 16. Further, the display unit 100 may be directly attached to the inner surface of the back member 11A without using the intermediate member 13.

  The Peltier elements 20A to 20D include, for example, a plurality of N-type and P-type semiconductors arranged in order as N, P, N, P, N, P,. By connecting the wires in series, and connecting the + terminal of the power supply unit 22 to the P-type semiconductor and connecting the-terminal to the N-type semiconductor, one side of the semiconductor group absorbs heat and the other side absorbs the heat. It is designed to be a heat source.

  The thermal wiring 21 is connected to the surface on the heat absorption side, and is made of a material having excellent thermal conductivity such as copper, and has forms such as a plate-like body, a rod-like body, a linear body, a pipe, and a block.

  The Peltier elements 20A to 20D may be provided so as to cover the entire surface of the back member 11A by using a large size or increasing the number of use. However, with such a configuration, the Peltier elements 20A to 20D are expensive, which is not a good idea. On the other hand, when the Peltier elements 20A to 20D are attached directly to the back member 11A with a gap between them, the display unit 100 is uneven in temperature between the part that contacts the Peltier elements 20A to 20D and the part that does not contact it. In part, the display quality varies. Therefore, as shown in FIG. 3, a plurality of thermal wirings 21 are connected to one Peltier element using small Peltier elements 20A to 20D, and thermal wiring 21 is connected to each Peltier element and the back member 11A. Are connected so as to be even.

  Further, when it is desired to use the Peltier elements 20A to 20D only when necessary, for example, when it is desired to operate only when the inside of the main body 11 is above a certain temperature, a temperature sensor is installed in the main body 11 to detect this temperature. The Peltier elements 20 </ b> A to 20 </ b> D may be configured to be turned on / off by the power source / control unit 16 based on the values.

(Operation of image display device)
Next, the operation of the second embodiment will be described with reference to FIG. When the image display apparatus 1 is used outdoors on a sunny day and the display surface is irradiated with sunlight, the temperature of the display unit 100 rises, and the temperature is transferred to the back surface of the display unit 100 over time. Heat is transferred to 11A, and the temperature of the back member 11A rises.

  On the other hand, under the control of the control circuit in the power supply / control unit 16, a predetermined direct current is applied to the Peltier elements 20 </ b> A to 20 </ b> D from the power supply unit 22, and the Peltier elements 20 </ b> A to 20 </ b> D Operates to lower the temperature. When the Peltier elements 20 </ b> A to 20 </ b> D cool the thermal wiring 21, the back member 11 </ b> A is cooled by the thermal wiring 21. In addition, the thermal wiring 21 can be heated by reversing the energizing direction to the Peltier elements 20A to 20D, and thereby the temperature of the back member 11A can be increased.

(Effect of the second embodiment)
According to the second embodiment, the following effects can be obtained.
(A) Since the cooling points are dispersed by connecting the Peltier elements 20A to 20D and the back member 11A by the plurality of thermal wirings 21, the temperature rise of the display unit 100 is suppressed and the display unit 100 is extremely The temperature gradient is eliminated and display quality can be prevented from deteriorating.
(B) Since the cooling capacity can be increased by increasing the size of the Peltier elements 20A to 20D or increasing the number of the Peltier elements 20A to 20D, the occurrence of insufficient cooling can be prevented.
(C) Since the display unit 100 can be heated via the thermal wiring 21 and the back member 11A by reversing the energization direction to the Peltier elements 20A to 20D, the temperature is too low in a cold district or severe winter season. Therefore, it is possible to prevent the display from becoming unstable.
(D) By over-energizing the Peltier elements 20A to 20D, overcooling can be prevented.
(E) Since the Peltier elements 20A to 20D and the thermal wiring 21 are attached to the outside, restrictions on the layout can be eliminated.

[Third Embodiment]
FIG. 4 shows an image display apparatus according to the third embodiment of the present invention. Moreover, FIG. 5 shows the AA line cross section of FIG. The image display device 1 is installed in a box-shaped main body 11, a transparent plate 12 made of transparent plastic, glass or the like that is attached to the front surface of the main body 11 and functions as a protective cover, and a rear surface of the transparent plate 12. Display unit 100, a spacer 14 for preventing a Newton ring from being formed by forming a predetermined gap between the transparent plate 12 and the surface of the display unit 100, and copper or the like installed at the rear of the display unit 100 A mounting plate 23 as a close contact member made of a metal material, an evaporator 31 made of a copper pipe or the like meanderingly attached to the mounting plate 23, and a ceramic fiber, glass wool, foamed product coated so as to cover the evaporator 31 A heat insulating material 32, etc., pipes 33A and 33B connected to both ends of the evaporator 31, a throttle 34 provided in the middle of the pipe 33A, 33A and includes a condenser 35 provided between the pipe 33B, and a compressor 36 provided in the middle of the pipe 33B.

  Here, the evaporator 31, the constrictor 34, the condenser 35 and the compressor 36 constitute a heat pump as a cooling means and as a heat exchanger of a pipe circulation system. The evaporator 31, the constrictor 34, the condensation The circulation system connecting the compressor 35 and the compressor 36 is filled with refrigerant, and a throttle 34 is provided to control the flow rate. In addition, it can replace with a heat pump and can also use the heat exchanger of the pipeline circulation system by another operating principle.

(Operation of image display device)
Next, the operation of the third embodiment will be described with reference to FIG. 4 and FIG. When the image display device 1 is used outdoors on a clear day and the display surface is irradiated with sunlight, the temperature of the display unit 100 rises. The temperature on the front side of the display unit 100 is transferred to the back surface of the display unit 100 over time, and further transferred to the mounting plate 23.

  On the other hand, when the compressor 36 is driven so that the refrigerant flows from the condenser 35 to the constrictor 34, the refrigerant passes through the path of the compressor 36, the condenser 35, the constrictor 34, the evaporator 31, and the compressor 36. It circulates, heat is absorbed by the evaporator 31, and heat is radiated by the condenser 35. As a result, the mounting plate 23 is cooled, and further, the space between the mounting plate 23 and the display unit 100 is cooled by the mounting plate 23, whereby the display unit 100 is cooled from the back.

  In addition, if the flow of the refrigerant | coolant by the compressor 34 is reversed and it is made to flow from the evaporator 31 to the expansion device 34, the attachment plate 23 can be heated and, thereby, the temperature of the display unit 100 can be raised.

(Effect of the third embodiment)
According to the third embodiment, the following effects can be obtained.
(A) Since the mounting plate 23 is cooled by the heat pump and the display unit 100 is cooled by the mounting plate 23, the temperature rise of the display unit 100 is suppressed, and the display quality can be prevented from deteriorating.
(B) Since the cooling capacity can be increased by changing each part of the evaporator or the like, it is possible to prevent the occurrence of insufficient cooling.
(C) Since the attachment plate 23 can be heated by reversing the flow of the refrigerant, it is possible to prevent the display from becoming unstable due to the low temperature in a severe winter season or the like.
(D) Supercooling can be prevented by stopping the operation of the heat pump.

[Other embodiments]
In addition, this invention is not limited to said each embodiment, A various deformation | transformation is possible within the range which does not change the summary, and the component of each embodiment can be combined arbitrarily.
For example, the Peltier element shown in FIG. 3 may be connected to the back member 11A shown in FIG. 1 via a thermal wiring.

  In addition to the above, as a display recording medium having a memory property, a thermal recording medium using a leuco dye, a liquid crystal having a memory property represented by a ferroelectric liquid crystal, and a charged particle are moved to switch a display. Other display recording media such as an electrophoretic method, a particle rotation method in which charged particles are rotated to switch the display, and a magnetophoresis method in which the particles are moved by magnetism to switch the display may be used.

1 is a cross-sectional plan view showing an image display device according to a first embodiment of the present invention. It is sectional drawing which shows the detailed structure of the display unit shown in FIG. It is a plane sectional view showing an image display device concerning a 2nd embodiment of the present invention. It is a top view which shows the image display apparatus which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the AA line cross section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display apparatus 11 Main body 11A Back surface member 11B, 13A Concavity and convexity part 12 Transparent plate 13 Intermediate member 14 Spacer 15 Thermal conduction grease 16 Power supply / control unit 17 Air flow path 18A, 18B Adjustment screw 19 Heat radiation member 20A-20D Peltier element 21 Heat Wiring 22 Power supply portion 23 Mounting plate 31 Evaporator 32 Heat insulating material 33A, 33B Piping 34 Restrictor 35 Condenser 36 Compressor 100 Display unit 101A, 101B Substrate 102 Row electrode 103 Column electrode 104A, 104B Dielectric layer 105 Space portion 106A White Particle 106B Black particle 110 Illumination light 111 Display light E Line of sight

Claims (14)

An image is written by applying a voltage, and a display unit capable of displaying with no power supply,
A housing that holds the display unit in a sealed space so that the display surface of the display unit is visible from the outside;
An image display device comprising: a close contact member that is in close contact with the back surface of the display unit; and a heat radiating unit that dissipates heat generated from the display unit to the outside of the housing via the close contact member. .   The heat dissipating means is provided on the back side of the housing, and dissipates heat generated from the display unit to the outside via the contact member, and is interposed between the contact member and the back member. The image display device according to claim 1, further comprising a thermal conductive grease.   The image display device according to claim 2, wherein the contact member has an uneven shape on the heat conductive grease side.   The image display device according to claim 2, wherein the back member has an uneven shape on the heat conductive grease side.   The image display device according to claim 2, wherein the back member has an uneven shape on the outside side.   The image display device according to claim 2, wherein the back member has a concavo-convex shape on the heat conductive grease side and the external side.   The image display apparatus according to claim 2, wherein the heat radiating means includes a conduit through which air flows through the back member.   The image display device according to claim 7, wherein the air is forced to flow through the pipe by a fan.   The image display apparatus according to claim 1, wherein the heat dissipating unit includes a plurality of cooling elements that cool the heat generated from the display unit through the contact member.   The image display apparatus according to claim 9, wherein the plurality of cooling elements are connected to a plurality of locations of the contact member via a plurality of thermal wirings so that heat conduction is uniformly performed.   The image display device according to claim 9, wherein the cooling element is a Peltier element.   2. The image according to claim 1, wherein the heat dissipating means includes a heat exchanger of a type in which a refrigerant pipe is thermally connected to the contact member and the refrigerant is circulated in the refrigerant pipe. Display device.   The image display device according to claim 12, wherein the heat exchanger is a heat pump. The display unit is a toner-type image display medium that displays the image by moving colored particles in a space between a front substrate and a rear substrate according to an electric field formed by applying the voltage. The image display device according to claim 1.