JP2004280055A - Structure of optical incident electrode of optical interference display plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new structure and a material of an optical incident electrode which has a high quality of plate of an optical interference display and is manufactured at an excellent yield. <P>SOLUTION: The optical incident electrode 302 is a translucent electrode composed of a substrate 3021 and a dielectric layer 3022. A part of light is absorbed by the optical incident electrode 302 when incident light passes through the optical incident electrode 302. A substrate 3021 is manufactured from such conductive transparent materials as ITO, indium IZO, ZO and IO, for example, and a combinations of them. Material used for forming the dielectric layer 3022 is silicon oxide, silicon nitride or a metal oxide. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to optical interference displays. More particularly, the present invention relates to color variable pixels of an optical interference display.

  Due to their light weight and small size, display plates hold promise in the market for portable displays and displays with limited space. So far, modules for optical interference displays have been studied in addition to liquid crystal displays (LCDs), organic electroluminescent displays (OLEDs) and plasma display panels (PDPs).

  With reference to U.S. Patent No. 6,064,064, an array of visible light modulations that can be used in a display plate is disclosed. FIG. 1 shows a cross-sectional view of a modulation known in the art. Each modulation 100 consists of two walls 102 and 104. These two walls are supported by columns 106, after which a cavity 108 is formed. The distance between these two walls, the length of cavity 108, is D. The wall 102 having a certain absorptance is a translucent layer that partially absorbs visible light. The wall 104 is a light reflecting layer that can be deformed when a voltage is applied. The wall 102 includes a substrate 1021, a light absorbing layer 1022, and a dielectric layer 1023. When the incident light reaches the cavity 108 through the wall 102 or 104, only visible light with a wavelength that matches Equation 1 may be output.

  2D = Nλ (1.1)

  In the formula, N is a natural number.

  If the length D of the cavity 108 is equal to half the wavelength times any natural number, constructive interference is created and a sharp light wave is emitted. Meanwhile, if the observer follows the direction of the incident light, the reflected light having the wavelength λ1 will be observable. Thus, modulation 100 is "open."

  FIG. 2 shows a cross-sectional view of the modulation after the voltage has been applied. As shown in FIG. 2, the voltage causes the wall 104 to deform and collapse toward the wall 102. The distance between walls 102 and 104, ie, the length of cavity 108, is not exactly zero. It is d and d can be 0. If d is used instead of D in Equation 1.1, only visible light with wavelength λ2 that satisfies Equation 1.1 can create constructive interference and pass through. Due to the high absorption of the wall 102 for light with wavelength λ2, all incident visible light should be filtered, so that an observer following the direction of the incident light will see any reflected visible light. I can't. At this time, the modulation is "closed."

  Display panels with arrays of modulation require low energy, have short response times, and are bistable. It is practical for applications in display plates, especially for portable products such as mobile phones, PDAs, portable computers.

U.S. Pat. No. 5,835,255

There are several problems with conventional manufacturing methods for manufacturing modulation. Product quality is often not stable and yields are not high. These challenges increase with increasing plate size. The critical thing is the light incident electrode (prior art modulation wall 102). The light incident electrode includes a substrate, an absorption layer, and a dielectric layer. The absorbent layer is made from a metal that is less than 100 Å thick. The reason for using metal is that if the metal layer is sufficiently thin, it is translucent.
Therefore, it is essential to control the thickness of the metal layer to, for example, less than 100 angstroms. It is not difficult to form a metal layer thinner than 100 angstroms. It can be realized by a physical vapor deposition method or a sputtering method. Nevertheless, it is difficult to form a metal layer with a uniform thickness and stable properties. Due to such difficulties, the quality of the prior art modulation is usually not stable and the yield of the manufacturing process is low. The present invention provides a new material and a new structure of the absorbent layer, which can be used to solve the problem.

  One object of the present invention is to provide an optical interference display in which a novel material is used to form an absorbing layer. The quality of the optical interference display is stable, and the yield of the manufacturing process is high.

  It is a second object of the present invention to provide an optical interference display having a non-metallic absorbing layer. The quality of the optical interference display is stable, and the yield of the manufacturing process is high.

  It is a third object of the present invention to provide an optical interference display having a non-metallic multilayer absorbing layer. The quality of the optical interference display is stable, and the yield of the manufacturing process is high.

  According to the object of the present invention, which modifies the material and structure of the absorbing layer as described for the purpose of the present invention, a modulation used in an optical interference display is provided in a first embodiment. This modulation includes at least a light incident electrode and a light reflection electrode. The light incident electrode includes a substrate and a dielectric layer. The substrate is a conductive transparent layer with lower transparency (or higher absorption) than known metal absorbing layers. The thickness of the conductive substrate or the content of impurities in the conductive substrate can be increased to reduce transparency.

  In accordance with the purpose of the present invention, a second embodiment discloses a modulation used in an optical interference display. This modulation comprises at least a light incident electrode and a light reflecting electrode, and the light incident electrode comprises a substrate, an absorbing layer and a dielectric layer. The substrate is a first conductive transparent layer. A first dielectric layer is formed on a first conductive transparent layer, for example, a substrate, and then a second conductive transparent layer is formed on the first dielectric layer by sputtering. Thereafter, a second dielectric layer is deposited on the second conductive layer. The absorption layer includes a first dielectric layer and a second conductive transparent layer. The light is actually absorbed by the first (substrate) and the second conductive transparent layer, where the axis of the first conductive transparent layer and the axis and lattice of the second conductive transparent layer may be different. .

  According to the purpose of the present invention, a third embodiment provides a modulation used in an optical interference display. This modulation comprises at least a light incident electrode and a light reflecting electrode, and the light incident electrode comprises a substrate, an absorbing layer and a dielectric layer. The substrate is a first conductive transparent layer. On the substrate, at least two dielectric layers and two conductive transparent layers are alternately formed. The absorption layer consists of all layers except the top dielectric layer and the substrate. The light is actually absorbed by the substrate and the conductive transparent layer, where the axes and axis grids of all adjacent conductive transparent layers may be different.

  Based on the modulation disclosed herein, the absorber layer is not made from a well-known thin film metal layer (less than 100 Angstroms) due to the challenge of forming a uniform ultra-thin metal layer. In the present invention, the absorbing layer is made of a metal oxide or a multilayer comprising a conductive metal oxide layer and another dielectric layer. Since the optical transparency of the conductive metal oxide layer and the dielectric material is higher than the transparency of the metal, multilayers that are typically greater than 300 Angstroms are assumed to be thicker than metal layers known in the art. The use of multiple layers of conductive metal oxide layers and other dielectric layers offers several benefits. First, quality is improved, and manufacturing is more stable, especially when large plates are involved in the manufacturing process. And secondly, since a thick layer of metal oxide is used, it can function as both a conductive layer and an absorbing layer. There is no need to manufacture an extra conductive layer.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to clarify the principles of the invention.

  In order to provide further information on the structure of the optical interference display, three examples are shown here to illustrate the structure of the light entrance electrode of all modulations in the present invention.

  Please refer to FIG. FIG. 3 shows a cross-sectional view of the modulation of the first embodiment disclosed in the present invention. The modulation 303 includes at least a light incident electrode 302 and a light reflection electrode 304. The light incident electrode 302 and the light reflection electrode 304 are arranged in parallel. These two electrodes are supported by columns 308, where a cavity 310 is formed. Light incident electrode 302 and light reflective electrode 304 are selected from the group consisting of narrow band mirrors, broad band mirrors, non-metallic mirrors, metal mirrors, and combinations thereof.

  Referring to FIG. 4, FIG. 4 shows a cross-sectional view of the modulated light incident electrode disclosed in the first embodiment of the present invention. The light incident electrode 302 is a translucent electrode including the substrate 3021 and the dielectric layer 3022. As the incident light passes through the light incident electrode 302, a portion of the light is absorbed by the light incident electrode 302. The substrate 3021 is made of a conductive transparent material such as, for example, ITO, IZO, ZO, IO, and a combination thereof. The material used to form the dielectric layer 3022 is silicon oxide, silicon nitride or metal oxide.

  The transparency of the conductive transparent material is typically high, ie, greater than 80%, while the ideal transparency of the light incident electrode 302 is between about 20% to 70%. Methods for reducing the transparency of the substrate 3021 include increasing the thickness of the substrate 3021, adjusting manufacturing parameters to reduce the purity of the substrate, and the like. The thicker the substrate, the lower the achievable transparency. Therefore, increasing the thickness of the substrate decreases the transparency. Further, adjusting the manufacturing parameters to produce a substrate with a disordered grid that produces a variety of axes in all parts of the substrate is another way to reduce the transparency of the substrate. In addition, low purity substrates can be created by increasing the impurities in the substrate (> 100 ppm) to reduce the transparency of the substrate. It makes the grid of the substrate irregular. Also, impurities in the substrate are usually of low transparency. It also helps reduce overall clarity. The three methods discussed here can be used alone or in combination.

  Referring to FIG. 5, FIG. 5 shows a cross-sectional view of a modulation light incident electrode disclosed in the second embodiment. Similar to the light incident electrode 302 of the modulation 300 of FIG. 3, the light incident electrode 502 includes a substrate 5021, one first dielectric layer 5022, one conductive transparent layer 5023, and one second dielectric layer 5024. . Incident light passing through the light incident electrode 502 is partially absorbed. The substrate 5021 and the conductive transparent layer 5023 are made of a conductive transparent material such as ITO, IZO, ZO, and IO. The dielectric layer 5022 is made of silicon oxide, silicon nitride, or metal oxide.

  The substrate 5021 and the conductive transparent layer 5023 function as an absorption layer. However, the substrate is formed on a glass plate (not shown) and the conductive transparent layer is formed on the dielectric layer 5022. The grid is irregular and each axis is different. Therefore, the transparency of the absorbing layer can be made similar to the transparency of a known absorbing layer.

  Also, the transparency of the conductive transparent layer is reduced by reducing the purity of the substrate.

  Please refer to FIG. FIG. 6 shows a cross-sectional view of the modulation disclosed in the third embodiment of the present invention. Like the light incident electrode 302 of the modulation 300, the light incident electrode 602 includes a substrate 6021, one first dielectric layer 6022, one first conductive transparent layer 6023, one second dielectric layer 6024, and one It is a semi-transparent electrode composed of the second conductive transparent layer 6025 and one third dielectric layer 6026. As the incident light passes through the light incident electrode 602, a portion of the light is absorbed. The substrate 6021 and the two conductive transparent layers 6023 and 6025 are made of a conductive transparent material such as ITO, IZO, ZO, IO, and combinations thereof. The material for forming the dielectric layer 6022 is silicon oxide, silicon nitride, or metal oxide.

  The substrate 6021, the first conductive transparent layer 6023, and the second conductive transparent layer 6025 function as an absorption layer. The first dielectric layer 6022 formed over the substrate 6021 affects the composition of the first conductive transparent layer 6023. Therefore, the grid is irregular. Also, the lattice of the second dielectric layer 6024 and the first dielectric layer 6022 are different due to different conditions during the deposition. The lattice of the second conductive transparent layer 6025 is different from that of the first dielectric layer 6023 and the substrate 6021. The composition of the gratings and axes of all parts of the conductive transparent layer are all different. In addition, the composition of the multilayer can also increase the thickness of the absorbing layer. Therefore, the transparency of the absorption layer can be the same as the transparency of a known absorption layer.

  Here, the transparency of the conductive transparent layer is also reduced by reducing the purity of the substrate.

  The number of layers is not limited. It is an object of the present invention to provide a multi-layer absorbing layer made from a metal oxide and a combination of a metal oxide and a dielectric material instead of an ultra-thin metal. Both the quality of the absorbent layer and the stability of the manufacturing process are improved.

  It will be apparent to those skilled in the art that various modifications and variations can be made in the structure of the present invention without departing from the scope or spirit of the invention. In view of the above, the present invention is intended to cover modifications and variations of this invention as long as they fall within the scope of the following claims and their equivalents.

1 is a cross-sectional view of a prior art modulation. FIG. 2 is a cross-sectional view of a prior art modulation after a voltage has been applied. FIG. 4 is a cross-sectional view of a modulation according to one preferred embodiment of the present invention. FIG. 4 is a cross-sectional view of a modulated light incidence electrode according to one preferred embodiment of the present invention. FIG. 5 is a cross-sectional view of a modulated light incidence electrode according to another preferred embodiment of the present invention. FIG. 9 is a cross-sectional view of a modulation light incident electrode disclosed in a third embodiment of the present invention according to one preferred embodiment of the present invention.

Explanation of reference numerals

REFERENCE SIGNS LIST 100 modulation 102 wall 1021 substrate 1022 light absorbing layer 1023 dielectric layer 104 wall 106 support 108 cavity 300 modulation 302 light incident electrode 3021 substrate 3022 dielectric layer 303 modulation 304 light reflective electrode 308 support 310 cavity 502 light incident electrode 5021 substrate 5022 dielectric layer 5023 Conductive transparent layer 5024 Dielectric layer 602 Light incident electrode 6021 Substrate 6022 First dielectric layer 6023 First conductive transparent layer 6024 Second dielectric layer 6025 Second conductive transparent layer 6026 Third dielectric layer

Claims (6)

An optical interference display having at least one conductive transparent layer and at least one dielectric layer located on the conductive transparent layer and alternately arranged with the conductive transparent layer,
An optical interference display, wherein the incident light is irradiated from one side of the conductive transparent layer, and the material of the conductive transparent layer and the thickness of the conductive transparent layer absorb at least 30% of the incident light.   The optical interference display of claim 1, wherein the material of the conductive transparent layer is selected from the group consisting of ITO, IZO, ZO, IO, and combinations thereof.   2. The optical interference display of claim 1, wherein the material of the dielectric layer comprises silicon oxide, silicon nitride or metal oxide.   The optical interference display of claim 1, wherein the grid of the conductive transparent layer is irregular.   The optical interference display of claim 1, wherein the axes of all portions of the conductive transparent layer are different.   The optical interference display of claim 1, wherein the conductive transparent layer further comprises more than 100 ppm of impurities.

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