JP4783675B2 - Reflective display device - Google Patents

Description

  The present invention relates to a reflective display device that displays an image corresponding to an image signal on a display board by selectively driving the actuator unit according to an attribute of the input image signal.

  Conventionally, display devices such as a cathode ray tube (CRT) and a liquid crystal display device are known as display devices.

  As a cathode ray tube, an ordinary television receiver, a monitor device for a computer, and the like are known. However, although the screen is bright, the power consumption is large and the depth of the entire display device is larger than the screen size. There is a problem that becomes larger.

  On the other hand, the liquid crystal display device has the advantages that the entire device can be reduced in size and consumes less power, but there are problems that the screen brightness is poor and the screen viewing angle is narrow.

  Further, in these cathode ray tubes and liquid crystal display devices, when a color screen is used, the number of pixels must be three times that of a monochrome screen, which complicates the device itself, increases power consumption, and avoids an increase in cost. There was also a problem that it was not possible.

  Therefore, the present applicant has proposed a new display device in order to solve the above-mentioned problem (for example, see Patent Document 1). As shown in FIG. 16, this display device has an actuator unit 400 arranged for each pixel, and each actuator unit 400 is formed on the piezoelectric / electrostrictive layer 402 and the upper and lower surfaces of the piezoelectric / electrostrictive layer 402. An actuator body 408 having an upper electrode 404 and a lower electrode 406 formed respectively, and an actuator substrate 414 composed of a vibration part 410 and a fixing part 412 disposed below the actuator body 408. It is configured. The lower electrode 406 of the actuator unit body 408 is in contact with the vibration unit 410, and the actuator unit body 408 is supported by the vibration unit 410.

  The actuator substrate 414 is made of ceramics by integrating the vibrating portion 410 and the fixing portion 412. Further, the actuator substrate 414 has a recess 416 so that the vibrating portion 410 is thin.

  Further, a displacement transmission unit 420 for making the contact area with the optical waveguide plate 418 a predetermined size is connected to the upper electrode 404 of the actuator unit main body 408. In the example of FIG. 16, the displacement transmission unit 420 is disposed close to the optical waveguide plate 418 in the off-selected state or the non-selected state where the actuator unit 400 is stationary, and in the on-selected state, the optical waveguide plate 418. Are arranged so as to be in contact with each other at a distance shorter than the wavelength of light.

  Then, light 422 is introduced from, for example, an end of the optical waveguide plate 418. In this case, by adjusting the refractive index of the optical waveguide plate 418, all the light 422 is totally reflected inside without being transmitted through the front and back surfaces of the optical waveguide plate 418. In this state, a voltage signal corresponding to the attribute of the image signal is selectively applied to the actuator unit 400 through the upper electrode 404 and the lower electrode 406, and various displacements of on-selection, off-selection and non-selection are applied to the actuator unit 400. By performing the operation, contact / separation of the displacement transmission unit 420 with respect to the optical waveguide plate 418 is controlled, whereby scattered light (leakage light) 424 at a predetermined portion of the optical waveguide plate 418 is controlled, An image corresponding to the image signal is displayed on the optical waveguide plate 418.

  And when performing color display with this display device, for example, the light source of the three primary colors is switched, and the contact time between the optical waveguide plate and the displacement transmission plate is synchronized with the period of color development to control the light emission time of the three primary colors, or The contact time between the optical waveguide plate and the displacement transmission plate is controlled in synchronism with the period in which the light emission times of the three primary colors are developed.

  Therefore, the display device according to the proposed example has an advantage that the number of pixels does not need to be increased as compared with the case of a monochrome screen even when applied to a color display method.

JP 7-287176 A

  The present invention improves the configuration of the display device according to the proposed example, and simplifies the configuration for introducing external light or light from the light source, improves the brightness, improves the contrast, and improves the image quality of the display image. An object of the present invention is to provide a reflective display device that can be used.

A reflective display device according to the present invention includes a display panel on which light is incident, an actuator substrate provided to face one plate surface of the display panel, and one of the display boards among the actuator boards. A plurality of actuator units arranged on a surface facing the plate surface, each actuator unit being provided so as to be opposed to one plate surface of the display plate, and each pixel structure having at least a light reflection unit, A light-absorbing liquid filled between the display panel and the actuator substrate, and the actuator unit includes a shape-retaining layer and at least a pair of electrodes formed in the shape-retaining layer. It has a body, and a vibration unit which supports the actuator body, the actuator substrate includes a substrate layer, are formed on the substrate layer, versus the main actuator element A spacer layer having a void in a portion to be formed, and a thin plate layer formed on the spacer layer so as to block the void, and a thin portion of the thin plate layer corresponding to the void is the vibrating portion And the cavity has a thickness of 20 μm or less, and an on signal or an off signal is applied to the pair of electrodes of the actuator unit to drive the actuator unit, so that the actuator unit corresponds to the actuator unit. By bending and displacing the actuator part so as to displace the pixel structure in a direction approaching or separating from the display plate, and controlling the light absorption between the display plate and the pixel structure, An image is displayed on the display board. In addition, it is preferable that the said display board has transparency.

  As a result, it is not necessary to introduce external light or light from the light source so as to be totally reflected within the display board, but it is only necessary to apply external light or light from the light source to the display board. The structure for introducing the light can be greatly simplified.

Then, the pixel structure is displaced in a direction approaching the display plate, thereby reducing the thickness of the light-absorbing liquid between the display plate and the pixel structure, thereby causing the pixel structure to emit light. When the body is displaced in a direction away from the display panel, the thickness of the light-absorbing liquid between the display panel and the pixel structure is increased, so that the light is extinguished.

The displacement of the pixel structure is preferably 0.1 μm to 10 μm. Further, a plurality of the pixel structures may exist in a space filled with the light absorbing liquid, and a plurality of bars may be provided between the display plate and the actuator substrate .

The pixel structure may have a colored layer. In this case, the light reflecting portion constituting the pixel structure may also serve as a colored layer.

  Further, for example, a three primary color filter, a complementary color filter, or a colored scatterer may be used as the colored layer. Here, the colored scatterer is an opaque body in which a pigment or other pigment is dispersed in a resin, for example.

Here, the light-absorbing liquid (hereinafter referred to as a light absorber for convenience) is not limited to black. For example, a blue light absorber may be used. In this case, for example, when it is assumed that no color filter is used, a white point can be displayed on a blue background. If a red color filter is used in combination, a red dot can be displayed on a blue background.

In this way, the color combination of the color filter and the light absorber, Ru can select any of the background color and the display color.

  As the light absorber, a liquid in which pigments or dyes are dispersed, an emulsion, a gel, a flexible resin material, or a combination thereof can be used. Moreover, what impregnated the said liquid in sponge etc. can also be used.

  As the liquid, a low vapor pressure organic solvent, a pigment dispersed in oil / water, or a colored dye can be used. For example, carbon black is dispersed in silicone oil having high electrical insulation. Can be mentioned. As the silicone oil, it is preferable to select a low-viscosity oil because image display can be switched quickly. In addition, carbon black having a surface coating applied to improve electrical insulation is more preferably used.

As a method for controlling the light transmittance of the light absorber , it is preferable to change the thickness of the light absorber (the distance between the display panel and the pixel structure) by the displacement operation of the actuator unit. The value of the thickness and the amount of change are not particularly limited, but those of 0.1 μm or more and 10 μm or less are particularly preferably used.

Also, among the picture element assembly may be provided with irregularities in the portion facing the optical absorber. Since the unevenness of this forms the flow path of the light absorber, the effect of improving the response of the light emission / quenching. Moreover, it is also preferable that it is a convex type.

In addition, it is also preferable to provide a transparent layer in a portion of the pixel structure that faces the light absorber. The transparent layer, the combined height of the picture element assembly, for example, has a function of actuator unit is made to be a uniform thickness of the light absorber in the natural state. Of course, you may form the said unevenness | corrugation and convex surface shape in the said transparent layer.

  Further, by irradiating the display panel with light from the light source, light emission luminance and contrast can be improved, and visibility can be improved. As the gradation expression method, any one of area gradation, time gradation, voltage gradation, or a combination thereof is preferably used.

  By the way, the reflective display device according to the present invention has a feature that an ultra-thin and low-power display can be advantageously configured. Therefore, for example, the present invention is effective for a large screen display configured by arranging a plurality of the display devices in the vertical direction and the horizontal direction. Compared with a projector, no projection space is required, and the projector can be installed even in a narrow space.

  Moreover, by arbitrarily changing the arrangement number of the display device, it is possible to form a screen having various shapes such as a horizontal, vertical, and circular shape in addition to a normal rectangular display. In addition, a curved display can be formed by arranging in a curved manner.

  Applications of this large screen display include displays for public use in waiting rooms, lobbies, corridors, etc. in stations, hospitals, airports, libraries, department stores, hotels, wedding halls, etc., taking advantage of the features of thin, large screen and wide viewing angle. Can be mentioned. It can also be used in cinema complex screens, karaoke boxes, and mini theaters. Moreover, you may use not only indoors but outdoors.

  In the case of having a colored layer as the pixel structure, the colored layer may be formed on the light reflecting portion constituting the pixel structure, or may be formed on the front surface or the back surface of the display plate. Also good. In particular, when a large screen display is configured by arranging a large number of reflective display devices according to the present invention on a large display plate or frame (including a lattice frame), the front and back surfaces of the large display plate are colored. A layer may be formed. Further, a plate or a film having a colored layer may be provided on the display plate. In addition, when providing a colored layer in a display board, it is preferable that it is a color filter. In this case, the pixel structure may use any of a white scatterer, a colored scatterer, and a color filter as the colored layer, but a white scatterer is particularly preferable.

  As described above, according to the reflective display device of the present invention, the configuration for introducing light from the light source can be simplified, the luminance can be improved, the contrast can be improved, and the display image quality can be improved. .

  Several embodiments of the reflective display device according to the present invention will be described below with reference to FIGS.

  As shown in FIG. 1, the reflective display device 10A according to the first embodiment includes external light, light from a light source (not shown), or a combination thereof (hereinafter referred to as light 18 for convenience). And a drive unit 24 provided opposite to the back surface of the display plate 20 and arranged in a matrix or a staggered manner corresponding to the pixels. It is configured.

  For example, as shown in FIG. 2, one dot 26 is formed by two actuator sections 22 arranged in the vertical direction, and three dots 26 arranged in the horizontal direction (red dots 26R, green dots 26G and One pixel 28 is composed of blue dots 26B). Further, in the reflective display device 10A, the arrangement of the pixels 28 is 16 (48 dots) to 32 (96 dots) in the horizontal direction, and 16 (16 dots) to 32 (32 dots) in the vertical direction. Yes. One actuator 26 may constitute one dot 26, or two or more actuators 22 may constitute one dot 26.

  Further, in the reflective display device 10A, as shown in FIG. 1, the pixel structures 30 are laminated on the actuator portions 22, respectively. The pixel structure 30 has a function of increasing the contact area with the display panel 20 to an area corresponding to the pixel.

  The drive unit 24 includes an actuator substrate 32 made of, for example, ceramics, and the actuator unit 22 is disposed at a position corresponding to each pixel 28 of the actuator substrate 32. The actuator substrate 32 is disposed so that one principal surface faces the back surface of the display panel 20, and the one principal surface is a continuous surface (the same surface). Inside the actuator substrate 32, a void 34 is provided for forming a vibration section described later at a position corresponding to each pixel 28. Each void 34 communicates with the outside through a through hole 36 having a small diameter provided on the other end surface of the actuator substrate 32.

  Of the actuator substrate 32, the portion where the void 34 is formed is thin, and the other portion is thick. The thin portion functions as the vibrating portion 38 with a structure that is susceptible to vibration against external stress, and the portion other than the void 34 is thick and functions as the fixing portion 40 that supports the vibrating portion 38. It is like that.

  That is, the actuator substrate 32 is a laminate of the substrate layer 32A as the lowermost layer, the spacer layer 32B as the intermediate layer, and the thin plate layer 32C as the uppermost layer, and the portion corresponding to the actuator portion 22 in the spacer layer 32B. It can be grasped as an integral structure in which a void 34 is formed. The substrate layer 32A functions not only as a reinforcing substrate but also as a wiring substrate. The actuator substrate 32 may be integrally fired or retrofitted.

  Further, the light absorber 14 is filled between the display panel 20 and the actuator substrate 32. In this example, a light absorbing liquid is used as the light absorber 14.

  Here, specific examples of the actuator unit 22 and the pixel structure 30 will be described with reference to FIGS. 3 to 8 show a case where a light shielding layer 44 is provided between a crosspiece 42 and a display panel 20 described later.

  First, as shown in FIG. 3, the actuator unit 22 maintains the shape of the piezoelectric / electrostrictive layer, the antiferroelectric layer, etc. directly formed on the vibrating unit 38 in addition to the vibrating unit 38 and the fixed unit 40. The actuator unit body 23 includes a layer 46 and a pair of electrodes 48 (row electrode 48 a and column electrode 48 b) formed on the upper and lower surfaces of the shape retaining layer 46.

  As shown in FIG. 3, the pair of electrodes 48 may have a structure formed above and below the shape retaining layer 46 or a structure formed only on one side, or the pair of electrodes 48 are formed only on the shape retaining layer 46. You may make it do.

  When the pair of electrodes 48 is formed only on the shape retaining layer 46, the planar shape of the pair of electrodes 48 may be a shape in which a number of comb teeth are complementary to each other as shown in FIG. As disclosed in JP-A-10-78549, a spiral shape, a multi-branch shape, or the like can be adopted.

  When the planar shape of the shape-retaining layer 46 is, for example, elliptical, and the pair of electrodes 48 are formed in a comb shape, as shown in FIGS. 5A and 5B, a pair of electrodes is formed along the long axis of the shape-retaining layer 46. For example, 48 comb teeth are arranged, and as shown in FIGS. 6A and 6B, the comb teeth of the pair of electrodes 48 are arranged along the short axis of the shape retaining layer 46.

  Then, as shown in FIGS. 5A and 6A, the comb-tooth portions of the pair of electrodes 48 are included in the planar shape of the shape retaining layer 46, or as shown in FIGS. 5B and 6B, the pair of electrodes 48 For example, the comb teeth may protrude from the planar shape of the shape retaining layer 46. The configuration shown in FIGS. 5B and 6B is more advantageous in bending displacement of the actuator portion 22.

  As shown in FIG. 3, when a row electrode 48a, for example, is formed on the upper surface of the shape retention layer 46 and a column electrode 48b is formed on the lower surface of the shape retention layer 46 as a pair of electrodes 48, FIG. As shown, it is possible to bend and displace the actuator portion 22 in the other direction so as to be convex toward the display board 20 side, and although not shown, the actuator portion 22 may be protruded toward the space 34 side. It is also possible to bend and displace in the direction.

  On the other hand, for example, as shown in FIG. 1, the pixel configuration body 30 can be configured by a laminated body of a light reflection layer 50 and a color filter 52 as a displacement transmission section formed on the actuator section main body 23. In this example, a case where a white scatterer is used as the light reflecting layer 50 is shown. A colored scatterer may be used instead of the color filter 52. Moreover, you may use a colored scatterer as a light reflection layer. Of course, when the color filter 52 and the colored scatterer are not formed, the pixel structure 30 is constituted by the light reflecting layer 50.

  Further, in the reflective display device 10A, as shown in FIG. 1, the reflective display device 10A includes a crosspiece 42 formed in a portion other than the pixel structure 30 between the display panel 20 and the actuator substrate 32. The material of the crosspiece 42 is preferably one that does not deform with respect to heat and pressure.

  The crosspieces 42 can be formed on, for example, four sides of the pixel structure 30. Here, as shown in FIG. 7, the four sides of the pixel structure 30 include, for example, positions corresponding to the respective corners if the pixel structure 30 is substantially rectangular or oval in a plane. Shows a form shared with the adjacent pixel structure 30.

  As another example of the crosspiece 42, as shown in FIG. 8, the crosspiece 42 may be configured to have a window portion 42 a surrounding at least one pixel configuration body 30. As a typical configuration example, for example, the crosspiece 42 itself is formed in a plate shape, and a window portion (opening) 42 a having a shape similar to the outer shape of the pixel configuration body 30 is formed at a position corresponding to the pixel configuration body 30. To do. As a result, the entire side surface of the pixel structure 30 is surrounded by the crosspieces 42, and the adhesion between the actuator substrate 32 and the display panel 20 is further strengthened.

  Here, selection of each constituent member of the reflective display device 10A, particularly the material of each constituent member, will be described.

  First, the light 18 applied to the display panel 20 may be in the ultraviolet region, visible region, or infrared region. Light sources not shown include incandescent bulbs, deuterium discharge lamps, fluorescent lamps, mercury lamps, metal halide lamps, halogen lamps, xenon lamps, tritium lamps, light emitting diodes, lasers, plasma light sources, hot cathode tubes (or their filament-like hot cathodes). In place of the carbon nanotube-field emitter), a cold cathode tube or the like.

  The vibration part 38 is preferably a high heat resistant material. The reason for this is that when the actuator unit 22 has a structure in which the vibration unit 38 is directly supported by the fixing unit 40 without using a material having poor heat resistance such as an organic adhesive, at least when the shape retaining layer 46 is formed, the vibration unit In order to prevent the quality of 38 from changing, the vibration part 38 is preferably made of a high heat resistant material.

  In addition, the vibration unit 38 is electrically connected to the wirings connected to the row electrodes 48a and the wirings connected to the column electrodes 48b (for example, data lines) in the pair of electrodes 48 formed on the actuator substrate 32. An insulating material is preferred.

  Therefore, the vibration part 38 may be a high heat-resistant metal or a material such as enamel whose metal surface is coated with a ceramic material such as glass, but ceramic is optimal.

  As the ceramic constituting the vibration part 38, for example, stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, aluminum nitride, silicon nitride, glass, a mixture thereof, or the like can be used. Stabilized zirconium oxide has high mechanical strength, high toughness even when the vibration portion 38 is thin, high chemical toughness, low chemical reactivity with the shape retention layer 46 and the pair of electrodes 48, etc. Particularly preferred. Stabilized zirconium oxide includes stabilized zirconium oxide and partially stabilized zirconium oxide. Stabilized zirconium oxide has a crystal structure such as a cubic crystal and thus does not cause a phase transition.

  On the other hand, zirconium oxide undergoes a phase transition between monoclinic and tetragonal crystals at around 1000 ° C., and cracks may occur during this phase transition. Stabilized zirconium oxide contains 1 to 30 mol% of a stabilizer such as calcium oxide, magnesium oxide, yttrium oxide, scandium oxide, ytterbium oxide, cerium oxide, or an oxide of rare earth metal. In order to increase the mechanical strength of the vibration part 38, the stabilizer preferably contains yttrium oxide. At this time, yttrium oxide is preferably contained in an amount of 1.5 to 6 mol%, more preferably 2 to 4 mol%, and further 0.1 to 5 mol% of aluminum oxide. Is preferred.

  The crystal phase may be a cubic + monoclinic mixed phase, a tetragonal + monoclinic mixed phase, a cubic + tetragonal + monoclinic mixed phase, or the like. A tetragonal crystal or a mixed phase of tetragonal crystal + cubic crystal is most preferable from the viewpoint of strength, toughness, and durability.

  When the vibration part 38 is made of ceramics, a large number of crystal grains constitute the vibration part 38. In order to increase the mechanical strength of the vibration part 38, the average grain size of the crystal grains may be 0.05 to 2 μm. Preferably, it is 0.1-1 micrometer.

  The fixing part 40 is preferably made of ceramics, but may be the same ceramic as the material of the vibration part 38 or may be different. As the ceramics constituting the fixed portion 40, for example, stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, aluminum nitride, silicon nitride, glass, and the like, similar to the material of the vibrating portion 38. A mixture of the above can be used.

  In particular, the actuator substrate 32 used in the reflective display device 10A is preferably made of a material mainly composed of zirconium oxide, a material mainly composed of aluminum oxide, or a material mainly composed of a mixture thereof. The Among these, those mainly composed of zirconium oxide are more preferable.

  In addition, although clay etc. may be added as a sintering auxiliary agent, it is necessary to adjust an auxiliary | assistant component so that what is easy to vitrify, such as a silicon oxide and a boron oxide, is not included excessively. This is because these materials that are easily vitrified are advantageous in bonding the actuator substrate 32 and the shape-retaining layer 46, but promote the reaction between the actuator substrate 32 and the shape-retaining layer 46, and This is because it is difficult to maintain the composition, and as a result, the device characteristics are deteriorated.

  That is, silicon oxide or the like in the actuator substrate 32 may be limited to 3% or less, more preferably 1% or less by weight. Here, the main component refers to a component present at a ratio of 50% or more by weight.

  As described above, a piezoelectric / electrostrictive layer, an antiferroelectric layer, or the like can be used as the shape retention layer 46. When a piezoelectric / electrostrictive layer is used as the shape retention layer 46, the piezoelectric / electrostrictive layer is used. For example, lead zirconate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, lead manganese niobate, lead magnesium tantalate, lead nickel tantalate, lead antimony stannate, lead titanate, titanate Examples include ceramics containing barium, lead magnesium tungstate, lead cobalt niobate, or the like, or any combination thereof.

  It goes without saying that the main component may contain 50% by weight or more of these compounds. Among the ceramics, a ceramic containing lead zirconate is most frequently used as a constituent material of the piezoelectric / electrostrictive layer constituting the shape retention layer 46.

  Further, when the piezoelectric / electrostrictive layer is composed of ceramics, the ceramics may further include oxides such as lanthanum, calcium, strontium, molybdenum, tungsten, barium, niobium, zinc, nickel, manganese, or any of these. A combination of the above or other ceramics appropriately added may be used.

  For example, it is preferable to use a ceramic containing, as a main component, a component composed of lead magnesium niobate, lead zirconate and lead titanate, and further containing lanthanum or strontium.

  The piezoelectric / electrostrictive layer may be dense or porous, and in the case of being porous, the porosity is preferably 40% or less.

  When an antiferroelectric layer is used as the shape-retaining layer 46, the antiferroelectric layer is mainly composed of lead zirconate or a component composed of lead zirconate and lead stannate. Further, it is desirable to add lead lanthanum oxide to lead zirconate, or add lead zirconate or lead niobate to a component composed of lead zirconate and lead stannate.

  In particular, when an antiferroelectric film containing a component composed of lead zirconate and lead stannate as in the following composition is applied as a film-type element such as the actuator unit 22, it can be driven at a relatively low voltage. Therefore, it is particularly preferable.

Pb _0.99 Nb _0.02 [(Zr _x Sn _1-x ) _1-y Ti _y ] _0.98 O ₃
However, 0.5 <x <0.6, 0.05 <y <0.063, 0.01 <Nb <0.03
The antiferroelectric film may be porous, and in the case of being porous, the porosity is preferably 30% or less.

  As a method for forming the shape retaining layer 46 on the vibrating portion 38, various thick film forming methods such as a screen printing method, a dipping method, a coating method, and an electrophoresis method, an ion beam method, a sputtering method, and vacuum deposition are used. Various thin film forming methods such as a method, an ion plating method, a chemical vapor deposition method (CVD), and plating can be used.

  In this embodiment, a thick film forming method such as a screen printing method, a dipping method, a coating method, an electrophoresis method, or the like is suitably employed for forming the shape retaining layer 46 on the vibration part 38.

  These methods can be formed using paste, slurry, suspension, emulsion, sol or the like mainly composed of piezoelectric ceramic particles having an average particle diameter of 0.01 to 5 μm, preferably 0.05 to 3 μm. This is because good piezoelectric operation characteristics can be obtained.

  In particular, the electrophoretic method is capable of forming a film with high density and high shape accuracy, as well as “electrochemistry and industrial physical chemistry Vol. 53, No. 1 (1985), p 63-68 Kazuo Anzai. The authors have the characteristics described in the technical literature such as “Hirotsu” or “The 1st Electrophoresis Method for High-Order Forming of Ceramics Research Discussion (1998), p5-6, p23-24”. Accordingly, it is preferable to select and use a method as appropriate in consideration of required accuracy, reliability, and the like.

  The thickness of the vibrating portion 38 and the thickness of the shape retaining layer 46 are preferably the same dimension. This is because, when the thickness of the vibration part 38 is extremely larger than the thickness of the shape holding layer 46 (if it is different by one digit or more), the vibration part 38 works to prevent the shrinkage of the shape holding layer 46 against the firing shrinkage. The stress at the interface between the shape-retaining layer 46 and the actuator substrate 32 is increased and is easily peeled off. On the contrary, if the thickness dimension is approximately the same, the actuator substrate 32 (vibrating portion 38) can easily follow the firing shrinkage of the shape retaining layer 46, which is preferable for integration. Specifically, the thickness of the vibration part 38 is preferably 1 to 100 μm, more preferably 3 to 50 μm, and still more preferably 5 to 20 μm. On the other hand, the shape-retaining layer 46 has a thickness of preferably 5 to 100 μm, more preferably 5 to 50 μm, and still more preferably 5 to 30 μm.

  The row electrode 48a and the column electrode 48b formed on the upper and lower surfaces of the shape retaining layer 46, or the pair of electrodes 48 formed on the shape retaining layer 46 have an appropriate thickness depending on the application. The thickness is preferably from 01 to 50 μm, more preferably from 0.1 to 5 μm. The row electrode 48a and the column electrode 48b are preferably made of a conductive metal that is solid at room temperature. For example, simple metals or alloys containing aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, etc. Can be mentioned. Needless to say, these elements may be contained in any combination.

  The material of the display panel 20 is not limited as long as it has transparency. Specifically, for example, a multi-layer structure of light-transmitting plastics such as glass, quartz, and acrylic, light-transmitting ceramics, or materials having different refractive indexes. A body or a surface provided with a coating layer is a general one.

  The colored layers such as the color filter 52 and the colored scatterer included in the pixel structure 30 are layers used to extract only light in a specific wavelength region, for example, absorb, transmit, and reflect light of a specific wavelength. There are those that develop color by scattering, and those that convert incident light into another wavelength. A transparent body, a translucent body, and an opaque body can be used individually or in combination.

  For example, dyes, pigments, ions and other pigments and phosphors are dispersed and dissolved in rubber, organic resins, translucent ceramics, glass, liquids, etc. Includes a powder obtained by sintering or pressing a powder such as the above-described dye or phosphor. About a material and a structure, these may be used independently and may be used in combination.

  The difference between the color filter 52 and the colored scatterer is that the luminance of leaked light due to reflection and scattering only by the colored layer when the pixel structure 30 is displaced in the direction approaching the display panel 20 to make it emit light. If the value is 0.5 times or more of the luminance value of leakage light due to reflection and scattering of all components including the pixel component 30 and the actuator unit 22, the colored layer is defined as a colored scatterer, If it is less than 0.5 times, the colored layer is defined as the color filter 52.

  As a specific example of the measurement method, when the colored layer alone is brought into contact with the back surface of the display plate 20 irradiated with the light 18, the light that has passed through the display plate 20 from the colored layer and leaked to the front surface. When the pixel structure 30 is further brought into contact with the opposite surface of the colored layer that contacts the display panel 20, the front luminance of the light leaking to the front surface is B (nt). nt), the colored layer is a colored scatterer when A ≧ 0.5 × B is satisfied, and the color filter 52 when A <0.5 × B is satisfied.

  The above-mentioned front luminance means that the luminance meter is arranged so that the line connecting the luminance meter for measuring luminance and the colored layer is perpendicular to the surface of the display panel 20 in contact with the colored layer (of the luminance meter). The detection surface is brightness measured in parallel with the plate surface of the display panel 20.

  The advantage of the colored scatterer is that the color tone and brightness hardly change depending on the thickness of the layer, and as a layer formation method for that purpose, it is difficult to strictly control the layer thickness, but various applications such as screen printing with low cost are possible. Is possible.

  In addition, since the colored scatterer also serves as a displacement transmission unit, the layer formation process can be simplified, and since the overall layer thickness can be reduced, the overall thickness of the reflective display device 10A can be reduced. Further, it is possible to prevent a decrease in the amount of displacement of the actuator section 22 and improve the response speed.

  The advantage of the color filter 52 is that the display panel 20 is flat and has high surface smoothness. Therefore, when a layer is formed on the display panel 20 side, the layer formation is easy, the range of process selection is widened, and the cost is low. In addition, it is easy to control the layer thickness that affects the color tone and luminance.

  In addition, there is no restriction | limiting in particular as film forming methods, such as the light reflection layer 50, the color filter 52, and a colored scatterer, Various well-known film forming methods are applicable. For example, in addition to a film attaching method in which a chip-like or film-like colored layer is directly attached on the surface of the display plate 20 or the actuator unit 22, a color filter 52, a light reflecting layer 50 (in this example, a white scatterer), or the like. Raw material powder, paste, liquid, gas, ions, etc., thick film formation techniques such as screen printing, photolithography, spray dipping, coating, ion beam, sputtering, vacuum deposition, ion plating, CVD, plating There is a method of forming the light reflecting layer 50 and the color filter 52 by forming a film by a thin film forming method such as the above.

  In addition, a light emitting layer may be provided on all or part of the pixel structure 30. An example of the light emitting layer is a phosphor layer. This phosphor layer may be excited by invisible light (ultraviolet light or infrared light) to emit visible light, or may be excited by visible light to emit visible light.

  Moreover, a fluorescent pigment can also be used as the light emitting layer. When this fluorescent pigment is used, the color of the pigment itself, that is, the one that adds fluorescence with a wavelength that almost matches the reflected color, has a large color stimulus and emits vivid light. And a general daylight fluorescent pigment is preferably used.

  In addition, photostimulable phosphors, phosphors, and phosphorescent pigments are also used as the light emitting layer. These materials may be either organic materials or inorganic materials.

  And what formed the light emitting layer using the above-mentioned light emitting material independently, what formed the light emitting layer using what disperse | distributed these light emitting materials in resin, or dissolved these light emitting materials in resin. What formed the light emitting layer with what is used is preferably used.

  The afterglow time of the luminescent material is preferably 1 second or less, more preferably 30 milliseconds. More preferably, it is several milliseconds or less.

  When the light emitting layer is used as all or part of the pixel structure 30, the light source (not shown) includes light having a wavelength for exciting the light emitting layer and has a sufficient energy density for excitation. There is no particular limitation. For example, a cold cathode tube, a hot cathode tube (or a carbon nanotube-field emitter disposed in place of the filament-like hot cathode), a metal halide lamp, a xenon lamp, a laser including an infrared laser, a black light, a halogen lamp, an incandescent light bulb Deuterium discharge lamps, fluorescent lamps, mercury lamps, tritium lamps, light emitting diodes, plasma light sources, and the like are used.

  Next, the operation of the reflective display device 10A will be briefly described with reference to FIG. First, the light 18 is irradiated on the display panel 20.

  In this example, in the natural state of all the actuator units 22, the actuator units are in an off state, and the end surface of the pixel structure 30 is separated from the back surface of the display panel 20.

  Therefore, the light absorber 14 (light-absorbing liquid) exists between the end surfaces of all the pixel components 30 and the back surface of the display panel 20. As a result, the light 18 applied to the display panel 20 is absorbed by the light absorber 14 (light absorbing liquid), and the off state is realized in the form of quenching. That is, black is displayed from the screen of the reflective display device 10A.

  From this state, when an ON signal is applied to the actuator unit 22 corresponding to a certain dot 26, the actuator unit 22 is bent and displaced so as to protrude toward the display panel 20, as shown in FIG. The end surface of the pixel structure 30 is brought into contact with the back surface of the display panel 20 by being bent and displaced in the direction. At this time, the light-absorbing liquid 14 existing on the upper portion of the end surface of the pixel structure 30 is pushed outward (around) the pixel structure 30 so that the end surface of the pixel structure 30 is directly connected to the display plate 20. Will come into contact with the back of the.

  At this stage, the light 18 is reflected by the surface of the light reflection layer 50 in the pixel structure 30 and becomes scattered light 62. A part of the scattered light 62 is reflected again in the display board 20, but most of the scattered light 62 is not reflected by the display board 20 but is transmitted through the front surface (surface) of the display board 20. Become.

  Accordingly, the actuator unit 22 to which the ON signal is applied is turned on, and the on state is realized in the form of light emission, and the emission color corresponds to the color of the color filter 52 included in the pixel structure 30. It will be a thing.

  That is, the reflective display device 10 </ b> A is configured such that the light absorbing liquid 14 between the display plate 20 and the pixel structure 30 is moved by the displacement operation in the approaching or separating direction of the pixel structure 30 to the display plate 20. Permeability can be controlled.

  In particular, in the reflection type display device 10A, one unit in which one unit for moving the pixel structure 30 in the approaching / separating direction with respect to the display plate 20 is arranged in the vertical direction is defined as one dot. Since three pixels (red dots 26R, green dots 26G, and blue dots 26B) are arranged as one pixel and many pixels are arranged in a matrix or staggered with respect to each row, the input image signal By controlling the displacement operation at each pixel in accordance with the attribute, a color image (character or Graphics, etc.) can be displayed.

  Thus, in the reflective display device 10A according to the first embodiment, the light 18 from the external light or the light source is not introduced so as to be totally reflected in the display plate 20, but from the external light or the light source. Therefore, the configuration for introducing external light or light 18 from the light source can be greatly simplified.

  In addition, when the actuator unit 22 is off, the light absorber 14 (light absorbing liquid) exists between the end face of the pixel structure 30 corresponding to the actuator unit 22 and the display panel 20. Therefore, it is possible to surely extinguish the light, there is almost no crosstalk on the display, and it is possible to improve the brightness, improve the contrast, and improve the image quality of the display image.

  In the above-described example, the end face of the pixel structure 30 is separated from the display board 20 in the natural state of the actuator unit 22, and the end face of the pixel structure 30 is in contact with the display board 20 by applying an ON signal. In addition, as shown in the reflective display device 10Aa according to the first modified example of FIG. 9, in the natural state of the actuator unit 22, the end face of the pixel structure 30 contacts the display plate 20, and the off signal is applied. You may make it employ | adopt the form which the end surface of the pixel structure 30 separates from the display board 20. FIG.

  Further, as shown in the reflective display device 10Ab according to the second modified example of FIG. 10, the thickness of the spacer layer 32B constituting the actuator substrate 32 may be reduced.

  Specifically, the spacer layer 32 </ b> B only needs to be present as a space 34 in the actuator substrate 32, and the thickness thereof is not particularly limited. However, on the other hand, the thickness may be determined according to the purpose of use of the space 34, and among them, the actuator portion 22 does not have a thickness more than necessary to function, and is thin as shown in FIG. 10, for example. It is preferable to be configured in a state. That is, the thickness of the spacer layer 32B is preferably about the magnitude of the displacement of the actuator part 22 to be used. The thickness of the thin plate layer 32C is usually 50 μm or less and preferably about 3 to 20 μm in order to greatly displace the actuator portion 22.

  With such a configuration, the bending of the thin portion (vibration portion 38 portion) is limited by the substrate layer 32A close to the bending direction, and the destruction of the thin portion is prevented against unintended application of external force. The effect is obtained. In addition, it is also possible to stabilize the displacement of the actuator part 22 to a specific value by utilizing the effect of limiting the bending by the substrate layer 32A.

  Further, since the thickness of the actuator substrate 32 itself can be reduced and the bending rigidity can be reduced by making the spacer layer 32B thin, for example, when the actuator substrate 32 is bonded and fixed to a separate body, for example, a counterpart (for example, a display board) 20), it is possible to effectively correct the warpage of itself (in this case, the actuator substrate 32) and improve the reliability of adhesion and fixation.

  In addition, since the actuator substrate 32 is configured to be thin as a whole, the amount of raw materials used in manufacturing the actuator substrate 32 can be reduced, and this structure is advantageous from the viewpoint of manufacturing cost. Therefore, the specific thickness of the spacer layer 32B is preferably 3 to 5 μm, and more preferably 3 to 20 μm.

  On the other hand, the thickness of the substrate layer 32A is generally 50 μm, preferably about 80 to 300 μm, for the purpose of reinforcing the entire actuator substrate 32, because the spacer layer 32B described above is formed thin.

  Next, a reflective display device 10B according to a second embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the thing corresponding to FIG. 1, and the duplicate description is abbreviate | omitted.

  As shown in FIG. 11, the reflective display device 10B according to the second embodiment has substantially the same configuration as the reflective display device 10A according to the first embodiment described above. 30 differs from the point that the light reflection layer 50 formed on the actuator unit main body 23 is formed and the color filter 52 is formed on the surface of the display panel 20. A light shielding layer 44 is formed between the color filters 52 for the purpose of reducing crosstalk on the display and improving the contrast.

  The reflective display device 10B according to the second embodiment also has a configuration for introducing external light or light from a light source, similar to the reflective display device 10A according to the first embodiment described above. Simplification, improvement in luminance, improvement in contrast, and improvement in display image quality can be achieved.

  Further, as shown in the reflective display device 10Ba according to the modification of FIG. 12, in the natural state of the actuator unit 22, the end face of the pixel structure 30 contacts the display plate 20, and the pixel structure 30 is applied by applying an off signal. Alternatively, the end face may be separated from the display panel 20.

  In the above-described example, the example in which the shape of the pixel structure 30, particularly the shape of the end face of the color filter 52 and the light reflection layer 50 is made uniform has been shown. However, as shown in FIG. 13 and FIG. For example, the upper part of the light reflecting layer 50 of the body 30 may be formed in a parabolic shape, a conical shape, a sawtooth shape, or a dome shape. In these cases, it is preferable to stack the second light reflection layer 102 such as aluminum and the color filter 52 on the surface, and to further fill the transparent layer 104 with the end face flush.

  In the figure, the light absorber 14 is filled over the entire area between the actuator substrate 32 and the display panel 20. However, the light absorber 14 is localized in the vicinity of the back surface of the display panel 20 or the upper surface of the pixel structure 30. It may be.

  Next, a reflective display device 10C according to a third embodiment will be described with reference to FIG.

  As shown in FIG. 15, the reflective display device 10 </ b> C according to the third embodiment has substantially the same configuration as the reflective display device 10 </ b> B according to the second embodiment described above. 30 includes a light absorption layer 110 formed on the actuator unit main body 23 and a color filter 52 formed on the surface of the display panel 20, and a light reflector 112 is provided between the display panel 20 and the actuator substrate 32. It differs in that it is filled. In this example, a case where a light reflective liquid is used as the light reflector 112 is shown.

  In this case, contrary to the reflective display device 10B according to the second embodiment, the light reflector 112 is disposed on the back surface of the display plate 20 for dots whose end surfaces of the pixel structure 30 are separated from the display plate 20. Therefore, the light 18 is reflected by the surface of the light reflector 112 and becomes scattered light 62. Most of the scattered light 62 is not reflected by the display plate 20 but is transmitted through the front surface (front surface) of the display plate 20 to be in a light emitting state.

  On the other hand, for the dots whose end face of the pixel structure 30 is in contact with the back surface of the display plate 20, the light absorption layer 110 is in contact with the back surface of the display plate 20. The light is extinguished.

  In the reflective display device 10C according to the third embodiment, as in the reflective display device 10A according to the first embodiment described above, a configuration for introducing external light or light 18 from a light source is used. Can be simplified, the luminance can be improved, the contrast can be improved, and the quality of the display image can be improved.

  Further, as the light reflector 112, for example, a blue light reflector may be used. In this case, for example, black display can be performed on a blue background.

  Here, a preferable aspect in the reflective display devices 10A, 10B, and 10C according to the first to third embodiments will be described.

  First, the light absorber 14 in the reflective display devices 10A and 10B according to the first and second embodiments is not limited to black. For example, a blue light absorber may be used. In this case, for example, when it is assumed that the color filter 52 is not used, a white point can be displayed on a blue background. If a red color filter is used in combination, a red dot can be displayed on a blue background. In this way, an arbitrary background color or display color can be selected by a combination of the colors of the color filter 52 and the light absorber 14.

  Similarly, when the light absorption layer 110 is formed as a component of the pixel structure 30 as in the reflective display device 10C according to the third embodiment, for example, black display may be performed on a blue background. it can.

  As the light absorber 14, a black or colored liquid, a solution, a gel, a flexible resin material, or the like can be used. Moreover, what impregnated the said liquid in sponge etc. can be used.

  As the light reflector 112, white, silver or colored liquid, solution / gel / sponge, flexible resin material, mercury, or the like can be used. What impregnated the said liquid in sponge etc. is used.

  As a method for controlling the light transmittance of the light absorber 14 or the light reflector 112, the thickness of the light absorber 14 or the light reflector 112 (the distance between the display panel 20 and the pixel component 30) is determined by the displacement operation of the actuator unit. Is preferably used. The value of the thickness and the amount of change are not particularly limited, but those of 0.1 μm or more and 10 μm or less are particularly preferably used.

  Further, the pixel structure 30 may be provided with unevenness on the portion facing the light absorber 14 or the light reflector 112. In the case where the light absorber 14 and / or the light reflector 112 is a fluid, the unevenness forms a flow path, so that there is an effect of improving the response of light emission / quenching. Moreover, it is also preferable that it is a convex type.

  In addition, it is also preferable to provide a transparent layer in a portion of the pixel structure 30 that faces the light absorber 14 or the light reflector 112. This transparent layer matches the height of the pixel structure 30 and, for example, the actuator unit 22 makes the thickness of the light absorber 14 and / or the light reflector 112 between the display plate 20 and the pixel structure 30 in a natural state uniform. It has a function to become. Of course, you may form the said unevenness | corrugation and convex surface shape in the said transparent layer.

  Further, by irradiating the display plate 20 with light from the light source, light emission luminance and contrast can be improved, and visibility can be improved. As the gradation expression method, any one of area gradation, time gradation, voltage gradation, or a combination thereof is preferably used.

  By the way, the reflective display devices 10A to 10C according to the first to third embodiments have a feature that an ultra-thin and low-power display can be advantageously configured. Therefore, for example, it is effective for a large-screen display configured by arranging a plurality of reflective display devices 10A to 10C in the vertical and horizontal directions. Compared with a projector, no projection space is required, and the projector can be installed even in a narrow space.

  Moreover, by arbitrarily changing the number of arrangements of the reflective display devices 10A to 10C and the like, it is possible to form screens of various shapes such as horizontally long, vertically long, and circular shapes in addition to the normal rectangular display. . In addition, a curved display can be formed by arranging in a curved manner.

  Applications of this large screen display include displays for public use in waiting rooms, lobbies, corridors, etc. in stations, hospitals, airports, libraries, department stores, hotels, wedding halls, etc., taking advantage of the features of thin, large screen and wide viewing angle. Can be mentioned. It can also be used in cinema complex screens, karaoke boxes, and mini theaters. Moreover, you may use not only indoors but outdoors.

  Further, in the above-described example, the example in which the colored layer such as the color filter 52 is formed on the top of the light reflection layer 50 constituting the pixel structure 30 or the surface of the display plate 20 is shown. You may make it form in a back surface. In particular, in the case of configuring a large screen display by arranging a large number of reflective display devices 10A to 10C according to the first to third embodiments on a large display board and frame (including a lattice frame) (not shown). A colored layer may be formed on the front surface or the back surface of the large display panel. Further, a plate or a film having a colored layer may be provided on the display plate 20 or a large display plate. In addition, when providing a colored layer in the display board 20 or a large sized display board, it is preferable that it is the color filter 52. FIG. In this case, the pixel structure 30 may use any of a white scatterer, a colored scatterer, and a color filter 52 as the colored layer, but a white scatterer is particularly preferable.

  Then, in order to display on the reflective display devices 10A to 10C according to the first to third embodiments, in order to supply a voltage to these reflective display devices 10A to 10C, an end portion of the actuator substrate 32 is used. This can be realized by connecting a lead wire, a connector, a printed circuit board, a flexible printed circuit board, or the like to the electrodes arranged near or on the back surface. Further, circuit elements may be formed or components may be mounted on the front and back surfaces of the actuator substrate 32. For example, a wiring board on which a connector, a driver IC, or the like is mounted is electrically and mechanically connected to the back side of the actuator substrate 32 (opposite the display surface) via a conductive adhesive or the like. Can be mentioned.

  As the wiring board, a printed board, a flexible printed board, a build-up board, a ceramic wiring board, or the like is preferably used. The wiring board may be a single layer or a multilayer. As an electrical connection method, in addition to the conductive adhesive, methods such as soldering, anisotropic conductive film, conductive rubber, wire bonding, lead frame, pin, spring, and crimping may be applied.

  Of course, the reflective display device according to the present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

It is a block diagram which shows the reflection type display apparatus which concerns on 1st Embodiment. It is explanatory drawing which shows the pixel structure of a reflection type display apparatus. It is explanatory drawing which shows the structure of an actuator part. It is a figure which shows an example of the planar shape of a pair of electrode formed in an actuator part. FIG. 5A is an explanatory view showing an example in which comb teeth of a pair of electrodes are arranged along the long axis of the shape-retaining layer, and FIG. 5B is an explanatory view showing another example. FIG. 6A is an explanatory view showing an example in which comb teeth of a pair of electrodes are arranged along the minor axis of the shape-retaining layer, and FIG. 6B is an explanatory view showing another example. It is explanatory drawing which shows a structure at the time of forming a crosspiece in the four directions of a pixel structure. It is explanatory drawing which shows the other structure of a crosspiece. It is a block diagram which shows the 1st modification of the reflection type display apparatus which concerns on 1st Embodiment. It is a block diagram which shows the 2nd modification of the reflection type display apparatus which concerns on 1st Embodiment. It is a block diagram which shows the reflection type display apparatus which concerns on 2nd Embodiment. It is a block diagram which shows the modification of the reflection type display apparatus which concerns on 2nd Embodiment. It is explanatory drawing which shows the example which made the upper part of the pixel structure the parabolic shape. It is explanatory drawing which shows the example which made the upper part of the pixel structure the conical shape. It is a block diagram which shows the reflection type display apparatus which concerns on 3rd Embodiment. It is a block diagram which shows the display apparatus which concerns on a proposal example.

Explanation of symbols

10A, 10Aa, 10Ab, 10B, 10Ba, 10C ... Reflective display device 14 ... Light absorber 20 ... Display board 22 ... Actuator part 23 ... Actuator part body 30 ... Pixel component 32 ... Actuator substrate 34 ... Empty 38 ... Vibration Numeral 42 ... Crosspiece 44 ... Light shielding layer 50 ... Light reflection layer 52 ... Color filter 110 ... Light absorption layer 112 ... Light reflector

Claims (5)

A display panel on which light is incident;
An actuator substrate provided to face one plate surface of the display plate;
Among the actuator substrates, a plurality of actuator units arranged on a surface facing one plate surface of the display plate,
Each actuator section is provided so as to face one plate surface of the display panel, and each pixel structure having at least a light reflection section,
A light-absorbing liquid filled between the display panel and the actuator substrate,
It said actuator portion includes an actuator body having at least a pair of electrodes formed on the shape-retaining layer and the shape-retaining layer, a vibrating section for supporting the main actuator element,
The actuator substrate includes a substrate layer, a spacer layer formed on the substrate layer, and having a space at a position corresponding to the actuator unit body, and a thin plate formed on the spacer layer so as to close the space. And having a layer
The thin portion of the thin plate layer corresponding to the void constitutes the vibrating portion,
The void has a thickness of 20 μm or less,
By applying an on signal or an off signal to the pair of electrodes of the actuator unit and driving the actuator unit, the pixel structure corresponding to the actuator unit is moved in a direction or separated from the display panel. A reflective display characterized in that an image is displayed on the display plate by controlling the light absorption between the display plate and the pixel structure by bending and displacing the actuator portion so as to displace apparatus. The reflective display device according to claim 1,
The reflection type display device, wherein the displacement of the pixel structure is 0.1 μm to 10 μm or less. The reflective display device according to claim 1 or 2,
In the space filled with the light-absorbing liquid, there are a plurality of the pixel structures,
A plurality of bars are provided between the display plate and the actuator substrate ,
The reflective display device , wherein the plurality of bars are provided at positions corresponding to respective vertices of a rectangle surrounding each of the plurality of pixel structures . The reflection type display device according to any one of claims 1 to 3 ,
The reflective display, wherein when the pixel structure is displaced in a direction away from the display plate, the vibrating portion is displaced inward of the space and contacts the substrate layer. apparatus. The reflection type display device according to any one of claims 1 to 4 ,
A reflective display device, wherein a portion of the pixel structure that faces the light-absorbing liquid has irregularities.

Images